Initial import

24 files changed, 20785 insertions, 0 deletions

diff --git a/fs/ceph/Kconfig b/fs/ceph/Kconfig
new file mode 100644
index 000000000..264e9bf83
--- /dev/null
+++ b/fs/ceph/Kconfig
@@ -0,0 +1,40 @@
+config CEPH_FS
+	tristate "Ceph distributed file system"
+	depends on INET
+	select CEPH_LIB
+	select LIBCRC32C
+	select CRYPTO_AES
+	select CRYPTO
+	default n
+	help
+	  Choose Y or M here to include support for mounting the
+	  experimental Ceph distributed file system.  Ceph is an extremely
+	  scalable file system designed to provide high performance,
+	  reliable access to petabytes of storage.
+
+	  More information at http://ceph.newdream.net/.
+
+	  If unsure, say N.
+
+if CEPH_FS
+config CEPH_FSCACHE
+	bool "Enable Ceph client caching support"
+	depends on CEPH_FS=m && FSCACHE || CEPH_FS=y && FSCACHE=y
+	help
+	  Choose Y here to enable persistent, read-only local
+	  caching support for Ceph clients using FS-Cache
+
+endif
+
+config CEPH_FS_POSIX_ACL
+	bool "Ceph POSIX Access Control Lists"
+	depends on CEPH_FS
+	select FS_POSIX_ACL
+	help
+	  POSIX Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  To learn more about Access Control Lists, visit the POSIX ACLs for
+	  Linux website <http://acl.bestbits.at/>.
+
+	  If you don't know what Access Control Lists are, say N
diff --git a/fs/ceph/Makefile b/fs/ceph/Makefile
new file mode 100644
index 000000000..85a4230b9
--- /dev/null
+++ b/fs/ceph/Makefile
@@ -0,0 +1,13 @@
+#
+# Makefile for CEPH filesystem.
+#
+
+obj-$(CONFIG_CEPH_FS) += ceph.o
+
+ceph-y := super.o inode.o dir.o file.o locks.o addr.o ioctl.o \
+	export.o caps.o snap.o xattr.o \
+	mds_client.o mdsmap.o strings.o ceph_frag.o \
+	debugfs.o
+
+ceph-$(CONFIG_CEPH_FSCACHE) += cache.o
+ceph-$(CONFIG_CEPH_FS_POSIX_ACL) += acl.o
diff --git a/fs/ceph/acl.c b/fs/ceph/acl.c
new file mode 100644
index 000000000..64fa24834
--- /dev/null
+++ b/fs/ceph/acl.c
@@ -0,0 +1,263 @@
+/*
+ * linux/fs/ceph/acl.c
+ *
+ * Copyright (C) 2013 Guangliang Zhao, <lucienchao@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/ceph/ceph_debug.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/posix_acl.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "super.h"
+
+static inline void ceph_set_cached_acl(struct inode *inode,
+					int type, struct posix_acl *acl)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	spin_lock(&ci->i_ceph_lock);
+	if (__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 0))
+		set_cached_acl(inode, type, acl);
+	spin_unlock(&ci->i_ceph_lock);
+}
+
+struct posix_acl *ceph_get_acl(struct inode *inode, int type)
+{
+	int size;
+	const char *name;
+	char *value = NULL;
+	struct posix_acl *acl;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name = POSIX_ACL_XATTR_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name = POSIX_ACL_XATTR_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+
+	size = __ceph_getxattr(inode, name, "", 0);
+	if (size > 0) {
+		value = kzalloc(size, GFP_NOFS);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		size = __ceph_getxattr(inode, name, value, size);
+	}
+
+	if (size > 0)
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
+	else if (size == -ERANGE || size == -ENODATA || size == 0)
+		acl = NULL;
+	else
+		acl = ERR_PTR(-EIO);
+
+	kfree(value);
+
+	if (!IS_ERR(acl))
+		ceph_set_cached_acl(inode, type, acl);
+
+	return acl;
+}
+
+int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	int ret = 0, size = 0;
+	const char *name = NULL;
+	char *value = NULL;
+	struct iattr newattrs;
+	umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
+	struct dentry *dentry;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name = POSIX_ACL_XATTR_ACCESS;
+		if (acl) {
+			ret = posix_acl_equiv_mode(acl, &new_mode);
+			if (ret < 0)
+				goto out;
+			if (ret == 0)
+				acl = NULL;
+		}
+		break;
+	case ACL_TYPE_DEFAULT:
+		if (!S_ISDIR(inode->i_mode)) {
+			ret = acl ? -EINVAL : 0;
+			goto out;
+		}
+		name = POSIX_ACL_XATTR_DEFAULT;
+		break;
+	default:
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (acl) {
+		size = posix_acl_xattr_size(acl->a_count);
+		value = kmalloc(size, GFP_NOFS);
+		if (!value) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+		if (ret < 0)
+			goto out_free;
+	}
+
+	dentry = d_find_alias(inode);
+	if (new_mode != old_mode) {
+		newattrs.ia_mode = new_mode;
+		newattrs.ia_valid = ATTR_MODE;
+		ret = ceph_setattr(dentry, &newattrs);
+		if (ret)
+			goto out_dput;
+	}
+
+	ret = __ceph_setxattr(dentry, name, value, size, 0);
+	if (ret) {
+		if (new_mode != old_mode) {
+			newattrs.ia_mode = old_mode;
+			newattrs.ia_valid = ATTR_MODE;
+			ceph_setattr(dentry, &newattrs);
+		}
+		goto out_dput;
+	}
+
+	ceph_set_cached_acl(inode, type, acl);
+
+out_dput:
+	dput(dentry);
+out_free:
+	kfree(value);
+out:
+	return ret;
+}
+
+int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
+		       struct ceph_acls_info *info)
+{
+	struct posix_acl *acl, *default_acl;
+	size_t val_size1 = 0, val_size2 = 0;
+	struct ceph_pagelist *pagelist = NULL;
+	void *tmp_buf = NULL;
+	int err;
+
+	err = posix_acl_create(dir, mode, &default_acl, &acl);
+	if (err)
+		return err;
+
+	if (acl) {
+		int ret = posix_acl_equiv_mode(acl, mode);
+		if (ret < 0)
+			goto out_err;
+		if (ret == 0) {
+			posix_acl_release(acl);
+			acl = NULL;
+		}
+	}
+
+	if (!default_acl && !acl)
+		return 0;
+
+	if (acl)
+		val_size1 = posix_acl_xattr_size(acl->a_count);
+	if (default_acl)
+		val_size2 = posix_acl_xattr_size(default_acl->a_count);
+
+	err = -ENOMEM;
+	tmp_buf = kmalloc(max(val_size1, val_size2), GFP_NOFS);
+	if (!tmp_buf)
+		goto out_err;
+	pagelist = kmalloc(sizeof(struct ceph_pagelist), GFP_NOFS);
+	if (!pagelist)
+		goto out_err;
+	ceph_pagelist_init(pagelist);
+
+	err = ceph_pagelist_reserve(pagelist, PAGE_SIZE);
+	if (err)
+		goto out_err;
+
+	ceph_pagelist_encode_32(pagelist, acl && default_acl ? 2 : 1);
+
+	if (acl) {
+		size_t len = strlen(POSIX_ACL_XATTR_ACCESS);
+		err = ceph_pagelist_reserve(pagelist, len + val_size1 + 8);
+		if (err)
+			goto out_err;
+		ceph_pagelist_encode_string(pagelist, POSIX_ACL_XATTR_ACCESS,
+					    len);
+		err = posix_acl_to_xattr(&init_user_ns, acl,
+					 tmp_buf, val_size1);
+		if (err < 0)
+			goto out_err;
+		ceph_pagelist_encode_32(pagelist, val_size1);
+		ceph_pagelist_append(pagelist, tmp_buf, val_size1);
+	}
+	if (default_acl) {
+		size_t len = strlen(POSIX_ACL_XATTR_DEFAULT);
+		err = ceph_pagelist_reserve(pagelist, len + val_size2 + 8);
+		if (err)
+			goto out_err;
+		err = ceph_pagelist_encode_string(pagelist,
+						  POSIX_ACL_XATTR_DEFAULT, len);
+		err = posix_acl_to_xattr(&init_user_ns, default_acl,
+					 tmp_buf, val_size2);
+		if (err < 0)
+			goto out_err;
+		ceph_pagelist_encode_32(pagelist, val_size2);
+		ceph_pagelist_append(pagelist, tmp_buf, val_size2);
+	}
+
+	kfree(tmp_buf);
+
+	info->acl = acl;
+	info->default_acl = default_acl;
+	info->pagelist = pagelist;
+	return 0;
+
+out_err:
+	posix_acl_release(acl);
+	posix_acl_release(default_acl);
+	kfree(tmp_buf);
+	if (pagelist)
+		ceph_pagelist_release(pagelist);
+	return err;
+}
+
+void ceph_init_inode_acls(struct inode* inode, struct ceph_acls_info *info)
+{
+	if (!inode)
+		return;
+	ceph_set_cached_acl(inode, ACL_TYPE_ACCESS, info->acl);
+	ceph_set_cached_acl(inode, ACL_TYPE_DEFAULT, info->default_acl);
+}
+
+void ceph_release_acls_info(struct ceph_acls_info *info)
+{
+	posix_acl_release(info->acl);
+	posix_acl_release(info->default_acl);
+	if (info->pagelist)
+		ceph_pagelist_release(info->pagelist);
+}
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
new file mode 100644
index 000000000..e162bcd10
--- /dev/null
+++ b/fs/ceph/addr.c
@@ -0,0 +1,1599 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/backing-dev.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>	/* generic_writepages */
+#include <linux/slab.h>
+#include <linux/pagevec.h>
+#include <linux/task_io_accounting_ops.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include "cache.h"
+#include <linux/ceph/osd_client.h>
+
+/*
+ * Ceph address space ops.
+ *
+ * There are a few funny things going on here.
+ *
+ * The page->private field is used to reference a struct
+ * ceph_snap_context for _every_ dirty page.  This indicates which
+ * snapshot the page was logically dirtied in, and thus which snap
+ * context needs to be associated with the osd write during writeback.
+ *
+ * Similarly, struct ceph_inode_info maintains a set of counters to
+ * count dirty pages on the inode.  In the absence of snapshots,
+ * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
+ *
+ * When a snapshot is taken (that is, when the client receives
+ * notification that a snapshot was taken), each inode with caps and
+ * with dirty pages (dirty pages implies there is a cap) gets a new
+ * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
+ * order, new snaps go to the tail).  The i_wrbuffer_ref_head count is
+ * moved to capsnap->dirty. (Unless a sync write is currently in
+ * progress.  In that case, the capsnap is said to be "pending", new
+ * writes cannot start, and the capsnap isn't "finalized" until the
+ * write completes (or fails) and a final size/mtime for the inode for
+ * that snap can be settled upon.)  i_wrbuffer_ref_head is reset to 0.
+ *
+ * On writeback, we must submit writes to the osd IN SNAP ORDER.  So,
+ * we look for the first capsnap in i_cap_snaps and write out pages in
+ * that snap context _only_.  Then we move on to the next capsnap,
+ * eventually reaching the "live" or "head" context (i.e., pages that
+ * are not yet snapped) and are writing the most recently dirtied
+ * pages.
+ *
+ * Invalidate and so forth must take care to ensure the dirty page
+ * accounting is preserved.
+ */
+
+#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
+#define CONGESTION_OFF_THRESH(congestion_kb)				\
+	(CONGESTION_ON_THRESH(congestion_kb) -				\
+	 (CONGESTION_ON_THRESH(congestion_kb) >> 2))
+
+static inline struct ceph_snap_context *page_snap_context(struct page *page)
+{
+	if (PagePrivate(page))
+		return (void *)page->private;
+	return NULL;
+}
+
+/*
+ * Dirty a page.  Optimistically adjust accounting, on the assumption
+ * that we won't race with invalidate.  If we do, readjust.
+ */
+static int ceph_set_page_dirty(struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode;
+	struct ceph_inode_info *ci;
+	struct ceph_snap_context *snapc;
+	int ret;
+
+	if (unlikely(!mapping))
+		return !TestSetPageDirty(page);
+
+	if (PageDirty(page)) {
+		dout("%p set_page_dirty %p idx %lu -- already dirty\n",
+		     mapping->host, page, page->index);
+		BUG_ON(!PagePrivate(page));
+		return 0;
+	}
+
+	inode = mapping->host;
+	ci = ceph_inode(inode);
+
+	/*
+	 * Note that we're grabbing a snapc ref here without holding
+	 * any locks!
+	 */
+	snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
+
+	/* dirty the head */
+	spin_lock(&ci->i_ceph_lock);
+	if (ci->i_head_snapc == NULL)
+		ci->i_head_snapc = ceph_get_snap_context(snapc);
+	++ci->i_wrbuffer_ref_head;
+	if (ci->i_wrbuffer_ref == 0)
+		ihold(inode);
+	++ci->i_wrbuffer_ref;
+	dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
+	     "snapc %p seq %lld (%d snaps)\n",
+	     mapping->host, page, page->index,
+	     ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
+	     ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
+	     snapc, snapc->seq, snapc->num_snaps);
+	spin_unlock(&ci->i_ceph_lock);
+
+	/*
+	 * Reference snap context in page->private.  Also set
+	 * PagePrivate so that we get invalidatepage callback.
+	 */
+	BUG_ON(PagePrivate(page));
+	page->private = (unsigned long)snapc;
+	SetPagePrivate(page);
+
+	ret = __set_page_dirty_nobuffers(page);
+	WARN_ON(!PageLocked(page));
+	WARN_ON(!page->mapping);
+
+	return ret;
+}
+
+/*
+ * If we are truncating the full page (i.e. offset == 0), adjust the
+ * dirty page counters appropriately.  Only called if there is private
+ * data on the page.
+ */
+static void ceph_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length)
+{
+	struct inode *inode;
+	struct ceph_inode_info *ci;
+	struct ceph_snap_context *snapc = page_snap_context(page);
+
+	inode = page->mapping->host;
+	ci = ceph_inode(inode);
+
+	if (offset != 0 || length != PAGE_CACHE_SIZE) {
+		dout("%p invalidatepage %p idx %lu partial dirty page %u~%u\n",
+		     inode, page, page->index, offset, length);
+		return;
+	}
+
+	ceph_invalidate_fscache_page(inode, page);
+
+	if (!PagePrivate(page))
+		return;
+
+	/*
+	 * We can get non-dirty pages here due to races between
+	 * set_page_dirty and truncate_complete_page; just spit out a
+	 * warning, in case we end up with accounting problems later.
+	 */
+	if (!PageDirty(page))
+		pr_err("%p invalidatepage %p page not dirty\n", inode, page);
+
+	ClearPageChecked(page);
+
+	dout("%p invalidatepage %p idx %lu full dirty page\n",
+	     inode, page, page->index);
+
+	ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
+	ceph_put_snap_context(snapc);
+	page->private = 0;
+	ClearPagePrivate(page);
+}
+
+static int ceph_releasepage(struct page *page, gfp_t g)
+{
+	struct inode *inode = page->mapping ? page->mapping->host : NULL;
+	dout("%p releasepage %p idx %lu\n", inode, page, page->index);
+	WARN_ON(PageDirty(page));
+
+	/* Can we release the page from the cache? */
+	if (!ceph_release_fscache_page(page, g))
+		return 0;
+
+	return !PagePrivate(page);
+}
+
+/*
+ * read a single page, without unlocking it.
+ */
+static int readpage_nounlock(struct file *filp, struct page *page)
+{
+	struct inode *inode = file_inode(filp);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_osd_client *osdc =
+		&ceph_inode_to_client(inode)->client->osdc;
+	int err = 0;
+	u64 off = page_offset(page);
+	u64 len = PAGE_CACHE_SIZE;
+
+	if (off >= i_size_read(inode)) {
+		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+		SetPageUptodate(page);
+		return 0;
+	}
+
+	if (ci->i_inline_version != CEPH_INLINE_NONE) {
+		/*
+		 * Uptodate inline data should have been added
+		 * into page cache while getting Fcr caps.
+		 */
+		if (off == 0)
+			return -EINVAL;
+		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+		SetPageUptodate(page);
+		return 0;
+	}
+
+	err = ceph_readpage_from_fscache(inode, page);
+	if (err == 0)
+		goto out;
+
+	dout("readpage inode %p file %p page %p index %lu\n",
+	     inode, filp, page, page->index);
+	err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
+				  off, &len,
+				  ci->i_truncate_seq, ci->i_truncate_size,
+				  &page, 1, 0);
+	if (err == -ENOENT)
+		err = 0;
+	if (err < 0) {
+		SetPageError(page);
+		ceph_fscache_readpage_cancel(inode, page);
+		goto out;
+	}
+	if (err < PAGE_CACHE_SIZE)
+		/* zero fill remainder of page */
+		zero_user_segment(page, err, PAGE_CACHE_SIZE);
+	else
+		flush_dcache_page(page);
+
+	SetPageUptodate(page);
+	ceph_readpage_to_fscache(inode, page);
+
+out:
+	return err < 0 ? err : 0;
+}
+
+static int ceph_readpage(struct file *filp, struct page *page)
+{
+	int r = readpage_nounlock(filp, page);
+	unlock_page(page);
+	return r;
+}
+
+/*
+ * Finish an async read(ahead) op.
+ */
+static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
+{
+	struct inode *inode = req->r_inode;
+	struct ceph_osd_data *osd_data;
+	int rc = req->r_result;
+	int bytes = le32_to_cpu(msg->hdr.data_len);
+	int num_pages;
+	int i;
+
+	dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
+
+	/* unlock all pages, zeroing any data we didn't read */
+	osd_data = osd_req_op_extent_osd_data(req, 0);
+	BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
+	num_pages = calc_pages_for((u64)osd_data->alignment,
+					(u64)osd_data->length);
+	for (i = 0; i < num_pages; i++) {
+		struct page *page = osd_data->pages[i];
+
+		if (rc < 0)
+			goto unlock;
+		if (bytes < (int)PAGE_CACHE_SIZE) {
+			/* zero (remainder of) page */
+			int s = bytes < 0 ? 0 : bytes;
+			zero_user_segment(page, s, PAGE_CACHE_SIZE);
+		}
+ 		dout("finish_read %p uptodate %p idx %lu\n", inode, page,
+		     page->index);
+		flush_dcache_page(page);
+		SetPageUptodate(page);
+		ceph_readpage_to_fscache(inode, page);
+unlock:
+		unlock_page(page);
+		page_cache_release(page);
+		bytes -= PAGE_CACHE_SIZE;
+	}
+	kfree(osd_data->pages);
+}
+
+static void ceph_unlock_page_vector(struct page **pages, int num_pages)
+{
+	int i;
+
+	for (i = 0; i < num_pages; i++)
+		unlock_page(pages[i]);
+}
+
+/*
+ * start an async read(ahead) operation.  return nr_pages we submitted
+ * a read for on success, or negative error code.
+ */
+static int start_read(struct inode *inode, struct list_head *page_list, int max)
+{
+	struct ceph_osd_client *osdc =
+		&ceph_inode_to_client(inode)->client->osdc;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct page *page = list_entry(page_list->prev, struct page, lru);
+	struct ceph_vino vino;
+	struct ceph_osd_request *req;
+	u64 off;
+	u64 len;
+	int i;
+	struct page **pages;
+	pgoff_t next_index;
+	int nr_pages = 0;
+	int ret;
+
+	off = (u64) page_offset(page);
+
+	/* count pages */
+	next_index = page->index;
+	list_for_each_entry_reverse(page, page_list, lru) {
+		if (page->index != next_index)
+			break;
+		nr_pages++;
+		next_index++;
+		if (max && nr_pages == max)
+			break;
+	}
+	len = nr_pages << PAGE_CACHE_SHIFT;
+	dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
+	     off, len);
+	vino = ceph_vino(inode);
+	req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len,
+				    0, 1, CEPH_OSD_OP_READ,
+				    CEPH_OSD_FLAG_READ, NULL,
+				    ci->i_truncate_seq, ci->i_truncate_size,
+				    false);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	/* build page vector */
+	nr_pages = calc_pages_for(0, len);
+	pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
+	ret = -ENOMEM;
+	if (!pages)
+		goto out;
+	for (i = 0; i < nr_pages; ++i) {
+		page = list_entry(page_list->prev, struct page, lru);
+		BUG_ON(PageLocked(page));
+		list_del(&page->lru);
+
+ 		dout("start_read %p adding %p idx %lu\n", inode, page,
+		     page->index);
+		if (add_to_page_cache_lru(page, &inode->i_data, page->index,
+					  GFP_NOFS)) {
+			ceph_fscache_uncache_page(inode, page);
+			page_cache_release(page);
+			dout("start_read %p add_to_page_cache failed %p\n",
+			     inode, page);
+			nr_pages = i;
+			goto out_pages;
+		}
+		pages[i] = page;
+	}
+	osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
+	req->r_callback = finish_read;
+	req->r_inode = inode;
+
+	ceph_osdc_build_request(req, off, NULL, vino.snap, NULL);
+
+	dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
+	ret = ceph_osdc_start_request(osdc, req, false);
+	if (ret < 0)
+		goto out_pages;
+	ceph_osdc_put_request(req);
+	return nr_pages;
+
+out_pages:
+	ceph_unlock_page_vector(pages, nr_pages);
+	ceph_release_page_vector(pages, nr_pages);
+out:
+	ceph_osdc_put_request(req);
+	return ret;
+}
+
+
+/*
+ * Read multiple pages.  Leave pages we don't read + unlock in page_list;
+ * the caller (VM) cleans them up.
+ */
+static int ceph_readpages(struct file *file, struct address_space *mapping,
+			  struct list_head *page_list, unsigned nr_pages)
+{
+	struct inode *inode = file_inode(file);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	int rc = 0;
+	int max = 0;
+
+	if (ceph_inode(inode)->i_inline_version != CEPH_INLINE_NONE)
+		return -EINVAL;
+
+	rc = ceph_readpages_from_fscache(mapping->host, mapping, page_list,
+					 &nr_pages);
+
+	if (rc == 0)
+		goto out;
+
+	if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE)
+		max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1)
+			>> PAGE_SHIFT;
+
+	dout("readpages %p file %p nr_pages %d max %d\n", inode,
+		file, nr_pages,
+	     max);
+	while (!list_empty(page_list)) {
+		rc = start_read(inode, page_list, max);
+		if (rc < 0)
+			goto out;
+		BUG_ON(rc == 0);
+	}
+out:
+	ceph_fscache_readpages_cancel(inode, page_list);
+
+	dout("readpages %p file %p ret %d\n", inode, file, rc);
+	return rc;
+}
+
+/*
+ * Get ref for the oldest snapc for an inode with dirty data... that is, the
+ * only snap context we are allowed to write back.
+ */
+static struct ceph_snap_context *get_oldest_context(struct inode *inode,
+						    u64 *snap_size)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_snap_context *snapc = NULL;
+	struct ceph_cap_snap *capsnap = NULL;
+
+	spin_lock(&ci->i_ceph_lock);
+	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
+		dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
+		     capsnap->context, capsnap->dirty_pages);
+		if (capsnap->dirty_pages) {
+			snapc = ceph_get_snap_context(capsnap->context);
+			if (snap_size)
+				*snap_size = capsnap->size;
+			break;
+		}
+	}
+	if (!snapc && ci->i_wrbuffer_ref_head) {
+		snapc = ceph_get_snap_context(ci->i_head_snapc);
+		dout(" head snapc %p has %d dirty pages\n",
+		     snapc, ci->i_wrbuffer_ref_head);
+	}
+	spin_unlock(&ci->i_ceph_lock);
+	return snapc;
+}
+
+/*
+ * Write a single page, but leave the page locked.
+ *
+ * If we get a write error, set the page error bit, but still adjust the
+ * dirty page accounting (i.e., page is no longer dirty).
+ */
+static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
+{
+	struct inode *inode;
+	struct ceph_inode_info *ci;
+	struct ceph_fs_client *fsc;
+	struct ceph_osd_client *osdc;
+	struct ceph_snap_context *snapc, *oldest;
+	loff_t page_off = page_offset(page);
+	long writeback_stat;
+	u64 truncate_size, snap_size = 0;
+	u32 truncate_seq;
+	int err = 0, len = PAGE_CACHE_SIZE;
+
+	dout("writepage %p idx %lu\n", page, page->index);
+
+	if (!page->mapping || !page->mapping->host) {
+		dout("writepage %p - no mapping\n", page);
+		return -EFAULT;
+	}
+	inode = page->mapping->host;
+	ci = ceph_inode(inode);
+	fsc = ceph_inode_to_client(inode);
+	osdc = &fsc->client->osdc;
+
+	/* verify this is a writeable snap context */
+	snapc = page_snap_context(page);
+	if (snapc == NULL) {
+		dout("writepage %p page %p not dirty?\n", inode, page);
+		goto out;
+	}
+	oldest = get_oldest_context(inode, &snap_size);
+	if (snapc->seq > oldest->seq) {
+		dout("writepage %p page %p snapc %p not writeable - noop\n",
+		     inode, page, snapc);
+		/* we should only noop if called by kswapd */
+		WARN_ON((current->flags & PF_MEMALLOC) == 0);
+		ceph_put_snap_context(oldest);
+		goto out;
+	}
+	ceph_put_snap_context(oldest);
+
+	spin_lock(&ci->i_ceph_lock);
+	truncate_seq = ci->i_truncate_seq;
+	truncate_size = ci->i_truncate_size;
+	if (!snap_size)
+		snap_size = i_size_read(inode);
+	spin_unlock(&ci->i_ceph_lock);
+
+	/* is this a partial page at end of file? */
+	if (page_off >= snap_size) {
+		dout("%p page eof %llu\n", page, snap_size);
+		goto out;
+	}
+	if (snap_size < page_off + len)
+		len = snap_size - page_off;
+
+	dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
+	     inode, page, page->index, page_off, len, snapc);
+
+	writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
+	if (writeback_stat >
+	    CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
+		set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
+
+	ceph_readpage_to_fscache(inode, page);
+
+	set_page_writeback(page);
+	err = ceph_osdc_writepages(osdc, ceph_vino(inode),
+				   &ci->i_layout, snapc,
+				   page_off, len,
+				   truncate_seq, truncate_size,
+				   &inode->i_mtime, &page, 1);
+	if (err < 0) {
+		dout("writepage setting page/mapping error %d %p\n", err, page);
+		SetPageError(page);
+		mapping_set_error(&inode->i_data, err);
+		if (wbc)
+			wbc->pages_skipped++;
+	} else {
+		dout("writepage cleaned page %p\n", page);
+		err = 0;  /* vfs expects us to return 0 */
+	}
+	page->private = 0;
+	ClearPagePrivate(page);
+	end_page_writeback(page);
+	ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
+	ceph_put_snap_context(snapc);  /* page's reference */
+out:
+	return err;
+}
+
+static int ceph_writepage(struct page *page, struct writeback_control *wbc)
+{
+	int err;
+	struct inode *inode = page->mapping->host;
+	BUG_ON(!inode);
+	ihold(inode);
+	err = writepage_nounlock(page, wbc);
+	unlock_page(page);
+	iput(inode);
+	return err;
+}
+
+
+/*
+ * lame release_pages helper.  release_pages() isn't exported to
+ * modules.
+ */
+static void ceph_release_pages(struct page **pages, int num)
+{
+	struct pagevec pvec;
+	int i;
+
+	pagevec_init(&pvec, 0);
+	for (i = 0; i < num; i++) {
+		if (pagevec_add(&pvec, pages[i]) == 0)
+			pagevec_release(&pvec);
+	}
+	pagevec_release(&pvec);
+}
+
+/*
+ * async writeback completion handler.
+ *
+ * If we get an error, set the mapping error bit, but not the individual
+ * page error bits.
+ */
+static void writepages_finish(struct ceph_osd_request *req,
+			      struct ceph_msg *msg)
+{
+	struct inode *inode = req->r_inode;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_osd_data *osd_data;
+	unsigned wrote;
+	struct page *page;
+	int num_pages;
+	int i;
+	struct ceph_snap_context *snapc = req->r_snapc;
+	struct address_space *mapping = inode->i_mapping;
+	int rc = req->r_result;
+	u64 bytes = req->r_ops[0].extent.length;
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	long writeback_stat;
+	unsigned issued = ceph_caps_issued(ci);
+
+	osd_data = osd_req_op_extent_osd_data(req, 0);
+	BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
+	num_pages = calc_pages_for((u64)osd_data->alignment,
+					(u64)osd_data->length);
+	if (rc >= 0) {
+		/*
+		 * Assume we wrote the pages we originally sent.  The
+		 * osd might reply with fewer pages if our writeback
+		 * raced with a truncation and was adjusted at the osd,
+		 * so don't believe the reply.
+		 */
+		wrote = num_pages;
+	} else {
+		wrote = 0;
+		mapping_set_error(mapping, rc);
+	}
+	dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
+	     inode, rc, bytes, wrote);
+
+	/* clean all pages */
+	for (i = 0; i < num_pages; i++) {
+		page = osd_data->pages[i];
+		BUG_ON(!page);
+		WARN_ON(!PageUptodate(page));
+
+		writeback_stat =
+			atomic_long_dec_return(&fsc->writeback_count);
+		if (writeback_stat <
+		    CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
+			clear_bdi_congested(&fsc->backing_dev_info,
+					    BLK_RW_ASYNC);
+
+		ceph_put_snap_context(page_snap_context(page));
+		page->private = 0;
+		ClearPagePrivate(page);
+		dout("unlocking %d %p\n", i, page);
+		end_page_writeback(page);
+
+		/*
+		 * We lost the cache cap, need to truncate the page before
+		 * it is unlocked, otherwise we'd truncate it later in the
+		 * page truncation thread, possibly losing some data that
+		 * raced its way in
+		 */
+		if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
+			generic_error_remove_page(inode->i_mapping, page);
+
+		unlock_page(page);
+	}
+	dout("%p wrote+cleaned %d pages\n", inode, wrote);
+	ceph_put_wrbuffer_cap_refs(ci, num_pages, snapc);
+
+	ceph_release_pages(osd_data->pages, num_pages);
+	if (osd_data->pages_from_pool)
+		mempool_free(osd_data->pages,
+			     ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
+	else
+		kfree(osd_data->pages);
+	ceph_osdc_put_request(req);
+}
+
+/*
+ * initiate async writeback
+ */
+static int ceph_writepages_start(struct address_space *mapping,
+				 struct writeback_control *wbc)
+{
+	struct inode *inode = mapping->host;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_vino vino = ceph_vino(inode);
+	pgoff_t index, start, end;
+	int range_whole = 0;
+	int should_loop = 1;
+	pgoff_t max_pages = 0, max_pages_ever = 0;
+	struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
+	struct pagevec pvec;
+	int done = 0;
+	int rc = 0;
+	unsigned wsize = 1 << inode->i_blkbits;
+	struct ceph_osd_request *req = NULL;
+	int do_sync = 0;
+	u64 truncate_size, snap_size;
+	u32 truncate_seq;
+
+	/*
+	 * Include a 'sync' in the OSD request if this is a data
+	 * integrity write (e.g., O_SYNC write or fsync()), or if our
+	 * cap is being revoked.
+	 */
+	if ((wbc->sync_mode == WB_SYNC_ALL) ||
+		ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
+		do_sync = 1;
+	dout("writepages_start %p dosync=%d (mode=%s)\n",
+	     inode, do_sync,
+	     wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
+	     (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
+
+	if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
+		pr_warn("writepage_start %p on forced umount\n", inode);
+		return -EIO; /* we're in a forced umount, don't write! */
+	}
+	if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
+		wsize = fsc->mount_options->wsize;
+	if (wsize < PAGE_CACHE_SIZE)
+		wsize = PAGE_CACHE_SIZE;
+	max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
+
+	pagevec_init(&pvec, 0);
+
+	/* where to start/end? */
+	if (wbc->range_cyclic) {
+		start = mapping->writeback_index; /* Start from prev offset */
+		end = -1;
+		dout(" cyclic, start at %lu\n", start);
+	} else {
+		start = wbc->range_start >> PAGE_CACHE_SHIFT;
+		end = wbc->range_end >> PAGE_CACHE_SHIFT;
+		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+			range_whole = 1;
+		should_loop = 0;
+		dout(" not cyclic, %lu to %lu\n", start, end);
+	}
+	index = start;
+
+retry:
+	/* find oldest snap context with dirty data */
+	ceph_put_snap_context(snapc);
+	snap_size = 0;
+	snapc = get_oldest_context(inode, &snap_size);
+	if (!snapc) {
+		/* hmm, why does writepages get called when there
+		   is no dirty data? */
+		dout(" no snap context with dirty data?\n");
+		goto out;
+	}
+	if (snap_size == 0)
+		snap_size = i_size_read(inode);
+	dout(" oldest snapc is %p seq %lld (%d snaps)\n",
+	     snapc, snapc->seq, snapc->num_snaps);
+
+	spin_lock(&ci->i_ceph_lock);
+	truncate_seq = ci->i_truncate_seq;
+	truncate_size = ci->i_truncate_size;
+	if (!snap_size)
+		snap_size = i_size_read(inode);
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (last_snapc && snapc != last_snapc) {
+		/* if we switched to a newer snapc, restart our scan at the
+		 * start of the original file range. */
+		dout("  snapc differs from last pass, restarting at %lu\n",
+		     index);
+		index = start;
+	}
+	last_snapc = snapc;
+
+	while (!done && index <= end) {
+		unsigned i;
+		int first;
+		pgoff_t next;
+		int pvec_pages, locked_pages;
+		struct page **pages = NULL;
+		mempool_t *pool = NULL;	/* Becomes non-null if mempool used */
+		struct page *page;
+		int want;
+		u64 offset, len;
+		long writeback_stat;
+
+		next = 0;
+		locked_pages = 0;
+		max_pages = max_pages_ever;
+
+get_more_pages:
+		first = -1;
+		want = min(end - index,
+			   min((pgoff_t)PAGEVEC_SIZE,
+			       max_pages - (pgoff_t)locked_pages) - 1)
+			+ 1;
+		pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+						PAGECACHE_TAG_DIRTY,
+						want);
+		dout("pagevec_lookup_tag got %d\n", pvec_pages);
+		if (!pvec_pages && !locked_pages)
+			break;
+		for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
+			page = pvec.pages[i];
+			dout("? %p idx %lu\n", page, page->index);
+			if (locked_pages == 0)
+				lock_page(page);  /* first page */
+			else if (!trylock_page(page))
+				break;
+
+			/* only dirty pages, or our accounting breaks */
+			if (unlikely(!PageDirty(page)) ||
+			    unlikely(page->mapping != mapping)) {
+				dout("!dirty or !mapping %p\n", page);
+				unlock_page(page);
+				break;
+			}
+			if (!wbc->range_cyclic && page->index > end) {
+				dout("end of range %p\n", page);
+				done = 1;
+				unlock_page(page);
+				break;
+			}
+			if (next && (page->index != next)) {
+				dout("not consecutive %p\n", page);
+				unlock_page(page);
+				break;
+			}
+			if (wbc->sync_mode != WB_SYNC_NONE) {
+				dout("waiting on writeback %p\n", page);
+				wait_on_page_writeback(page);
+			}
+			if (page_offset(page) >= snap_size) {
+				dout("%p page eof %llu\n", page, snap_size);
+				done = 1;
+				unlock_page(page);
+				break;
+			}
+			if (PageWriteback(page)) {
+				dout("%p under writeback\n", page);
+				unlock_page(page);
+				break;
+			}
+
+			/* only if matching snap context */
+			pgsnapc = page_snap_context(page);
+			if (pgsnapc->seq > snapc->seq) {
+				dout("page snapc %p %lld > oldest %p %lld\n",
+				     pgsnapc, pgsnapc->seq, snapc, snapc->seq);
+				unlock_page(page);
+				if (!locked_pages)
+					continue; /* keep looking for snap */
+				break;
+			}
+
+			if (!clear_page_dirty_for_io(page)) {
+				dout("%p !clear_page_dirty_for_io\n", page);
+				unlock_page(page);
+				break;
+			}
+
+			/*
+			 * We have something to write.  If this is
+			 * the first locked page this time through,
+			 * allocate an osd request and a page array
+			 * that it will use.
+			 */
+			if (locked_pages == 0) {
+				BUG_ON(pages);
+				/* prepare async write request */
+				offset = (u64)page_offset(page);
+				len = wsize;
+				req = ceph_osdc_new_request(&fsc->client->osdc,
+							&ci->i_layout, vino,
+							offset, &len, 0,
+							do_sync ? 2 : 1,
+							CEPH_OSD_OP_WRITE,
+							CEPH_OSD_FLAG_WRITE |
+							CEPH_OSD_FLAG_ONDISK,
+							snapc, truncate_seq,
+							truncate_size, true);
+				if (IS_ERR(req)) {
+					rc = PTR_ERR(req);
+					unlock_page(page);
+					break;
+				}
+
+				if (do_sync)
+					osd_req_op_init(req, 1, CEPH_OSD_OP_STARTSYNC);
+
+				req->r_callback = writepages_finish;
+				req->r_inode = inode;
+
+				max_pages = calc_pages_for(0, (u64)len);
+				pages = kmalloc(max_pages * sizeof (*pages),
+						GFP_NOFS);
+				if (!pages) {
+					pool = fsc->wb_pagevec_pool;
+					pages = mempool_alloc(pool, GFP_NOFS);
+					BUG_ON(!pages);
+				}
+			}
+
+			/* note position of first page in pvec */
+			if (first < 0)
+				first = i;
+			dout("%p will write page %p idx %lu\n",
+			     inode, page, page->index);
+
+			writeback_stat =
+			       atomic_long_inc_return(&fsc->writeback_count);
+			if (writeback_stat > CONGESTION_ON_THRESH(
+				    fsc->mount_options->congestion_kb)) {
+				set_bdi_congested(&fsc->backing_dev_info,
+						  BLK_RW_ASYNC);
+			}
+
+			set_page_writeback(page);
+			pages[locked_pages] = page;
+			locked_pages++;
+			next = page->index + 1;
+		}
+
+		/* did we get anything? */
+		if (!locked_pages)
+			goto release_pvec_pages;
+		if (i) {
+			int j;
+			BUG_ON(!locked_pages || first < 0);
+
+			if (pvec_pages && i == pvec_pages &&
+			    locked_pages < max_pages) {
+				dout("reached end pvec, trying for more\n");
+				pagevec_reinit(&pvec);
+				goto get_more_pages;
+			}
+
+			/* shift unused pages over in the pvec...  we
+			 * will need to release them below. */
+			for (j = i; j < pvec_pages; j++) {
+				dout(" pvec leftover page %p\n",
+				     pvec.pages[j]);
+				pvec.pages[j-i+first] = pvec.pages[j];
+			}
+			pvec.nr -= i-first;
+		}
+
+		/* Format the osd request message and submit the write */
+
+		offset = page_offset(pages[0]);
+		len = min(snap_size - offset,
+			  (u64)locked_pages << PAGE_CACHE_SHIFT);
+		dout("writepages got %d pages at %llu~%llu\n",
+		     locked_pages, offset, len);
+
+		osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
+							!!pool, false);
+
+		pages = NULL;	/* request message now owns the pages array */
+		pool = NULL;
+
+		/* Update the write op length in case we changed it */
+
+		osd_req_op_extent_update(req, 0, len);
+
+		vino = ceph_vino(inode);
+		ceph_osdc_build_request(req, offset, snapc, vino.snap,
+					&inode->i_mtime);
+
+		rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
+		BUG_ON(rc);
+		req = NULL;
+
+		/* continue? */
+		index = next;
+		wbc->nr_to_write -= locked_pages;
+		if (wbc->nr_to_write <= 0)
+			done = 1;
+
+release_pvec_pages:
+		dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
+		     pvec.nr ? pvec.pages[0] : NULL);
+		pagevec_release(&pvec);
+
+		if (locked_pages && !done)
+			goto retry;
+	}
+
+	if (should_loop && !done) {
+		/* more to do; loop back to beginning of file */
+		dout("writepages looping back to beginning of file\n");
+		should_loop = 0;
+		index = 0;
+		goto retry;
+	}
+
+	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+		mapping->writeback_index = index;
+
+out:
+	if (req)
+		ceph_osdc_put_request(req);
+	ceph_put_snap_context(snapc);
+	dout("writepages done, rc = %d\n", rc);
+	return rc;
+}
+
+
+
+/*
+ * See if a given @snapc is either writeable, or already written.
+ */
+static int context_is_writeable_or_written(struct inode *inode,
+					   struct ceph_snap_context *snapc)
+{
+	struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
+	int ret = !oldest || snapc->seq <= oldest->seq;
+
+	ceph_put_snap_context(oldest);
+	return ret;
+}
+
+/*
+ * We are only allowed to write into/dirty the page if the page is
+ * clean, or already dirty within the same snap context.
+ *
+ * called with page locked.
+ * return success with page locked,
+ * or any failure (incl -EAGAIN) with page unlocked.
+ */
+static int ceph_update_writeable_page(struct file *file,
+			    loff_t pos, unsigned len,
+			    struct page *page)
+{
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
+	loff_t page_off = pos & PAGE_CACHE_MASK;
+	int pos_in_page = pos & ~PAGE_CACHE_MASK;
+	int end_in_page = pos_in_page + len;
+	loff_t i_size;
+	int r;
+	struct ceph_snap_context *snapc, *oldest;
+
+retry_locked:
+	/* writepages currently holds page lock, but if we change that later, */
+	wait_on_page_writeback(page);
+
+	/* check snap context */
+	BUG_ON(!ci->i_snap_realm);
+	down_read(&mdsc->snap_rwsem);
+	BUG_ON(!ci->i_snap_realm->cached_context);
+	snapc = page_snap_context(page);
+	if (snapc && snapc != ci->i_head_snapc) {
+		/*
+		 * this page is already dirty in another (older) snap
+		 * context!  is it writeable now?
+		 */
+		oldest = get_oldest_context(inode, NULL);
+		up_read(&mdsc->snap_rwsem);
+
+		if (snapc->seq > oldest->seq) {
+			ceph_put_snap_context(oldest);
+			dout(" page %p snapc %p not current or oldest\n",
+			     page, snapc);
+			/*
+			 * queue for writeback, and wait for snapc to
+			 * be writeable or written
+			 */
+			snapc = ceph_get_snap_context(snapc);
+			unlock_page(page);
+			ceph_queue_writeback(inode);
+			r = wait_event_interruptible(ci->i_cap_wq,
+			       context_is_writeable_or_written(inode, snapc));
+			ceph_put_snap_context(snapc);
+			if (r == -ERESTARTSYS)
+				return r;
+			return -EAGAIN;
+		}
+		ceph_put_snap_context(oldest);
+
+		/* yay, writeable, do it now (without dropping page lock) */
+		dout(" page %p snapc %p not current, but oldest\n",
+		     page, snapc);
+		if (!clear_page_dirty_for_io(page))
+			goto retry_locked;
+		r = writepage_nounlock(page, NULL);
+		if (r < 0)
+			goto fail_nosnap;
+		goto retry_locked;
+	}
+
+	if (PageUptodate(page)) {
+		dout(" page %p already uptodate\n", page);
+		return 0;
+	}
+
+	/* full page? */
+	if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
+		return 0;
+
+	/* past end of file? */
+	i_size = inode->i_size;   /* caller holds i_mutex */
+
+	if (page_off >= i_size ||
+	    (pos_in_page == 0 && (pos+len) >= i_size &&
+	     end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
+		dout(" zeroing %p 0 - %d and %d - %d\n",
+		     page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
+		zero_user_segments(page,
+				   0, pos_in_page,
+				   end_in_page, PAGE_CACHE_SIZE);
+		return 0;
+	}
+
+	/* we need to read it. */
+	up_read(&mdsc->snap_rwsem);
+	r = readpage_nounlock(file, page);
+	if (r < 0)
+		goto fail_nosnap;
+	goto retry_locked;
+fail_nosnap:
+	unlock_page(page);
+	return r;
+}
+
+/*
+ * We are only allowed to write into/dirty the page if the page is
+ * clean, or already dirty within the same snap context.
+ */
+static int ceph_write_begin(struct file *file, struct address_space *mapping,
+			    loff_t pos, unsigned len, unsigned flags,
+			    struct page **pagep, void **fsdata)
+{
+	struct inode *inode = file_inode(file);
+	struct page *page;
+	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	int r;
+
+	do {
+		/* get a page */
+		page = grab_cache_page_write_begin(mapping, index, 0);
+		if (!page)
+			return -ENOMEM;
+		*pagep = page;
+
+		dout("write_begin file %p inode %p page %p %d~%d\n", file,
+		     inode, page, (int)pos, (int)len);
+
+		r = ceph_update_writeable_page(file, pos, len, page);
+		if (r < 0)
+			page_cache_release(page);
+		else
+			*pagep = page;
+	} while (r == -EAGAIN);
+
+	return r;
+}
+
+/*
+ * we don't do anything in here that simple_write_end doesn't do
+ * except adjust dirty page accounting and drop read lock on
+ * mdsc->snap_rwsem.
+ */
+static int ceph_write_end(struct file *file, struct address_space *mapping,
+			  loff_t pos, unsigned len, unsigned copied,
+			  struct page *page, void *fsdata)
+{
+	struct inode *inode = file_inode(file);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+	int check_cap = 0;
+
+	dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
+	     inode, page, (int)pos, (int)copied, (int)len);
+
+	/* zero the stale part of the page if we did a short copy */
+	if (copied < len)
+		zero_user_segment(page, from+copied, len);
+
+	/* did file size increase? */
+	/* (no need for i_size_read(); we caller holds i_mutex */
+	if (pos+copied > inode->i_size)
+		check_cap = ceph_inode_set_size(inode, pos+copied);
+
+	if (!PageUptodate(page))
+		SetPageUptodate(page);
+
+	set_page_dirty(page);
+
+	unlock_page(page);
+	up_read(&mdsc->snap_rwsem);
+	page_cache_release(page);
+
+	if (check_cap)
+		ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
+
+	return copied;
+}
+
+/*
+ * we set .direct_IO to indicate direct io is supported, but since we
+ * intercept O_DIRECT reads and writes early, this function should
+ * never get called.
+ */
+static ssize_t ceph_direct_io(struct kiocb *iocb, struct iov_iter *iter,
+			      loff_t pos)
+{
+	WARN_ON(1);
+	return -EINVAL;
+}
+
+const struct address_space_operations ceph_aops = {
+	.readpage = ceph_readpage,
+	.readpages = ceph_readpages,
+	.writepage = ceph_writepage,
+	.writepages = ceph_writepages_start,
+	.write_begin = ceph_write_begin,
+	.write_end = ceph_write_end,
+	.set_page_dirty = ceph_set_page_dirty,
+	.invalidatepage = ceph_invalidatepage,
+	.releasepage = ceph_releasepage,
+	.direct_IO = ceph_direct_io,
+};
+
+
+/*
+ * vm ops
+ */
+static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct inode *inode = file_inode(vma->vm_file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_file_info *fi = vma->vm_file->private_data;
+	struct page *pinned_page = NULL;
+	loff_t off = vmf->pgoff << PAGE_CACHE_SHIFT;
+	int want, got, ret;
+
+	dout("filemap_fault %p %llx.%llx %llu~%zd trying to get caps\n",
+	     inode, ceph_vinop(inode), off, (size_t)PAGE_CACHE_SIZE);
+	if (fi->fmode & CEPH_FILE_MODE_LAZY)
+		want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
+	else
+		want = CEPH_CAP_FILE_CACHE;
+	while (1) {
+		got = 0;
+		ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want,
+				    -1, &got, &pinned_page);
+		if (ret == 0)
+			break;
+		if (ret != -ERESTARTSYS) {
+			WARN_ON(1);
+			return VM_FAULT_SIGBUS;
+		}
+	}
+	dout("filemap_fault %p %llu~%zd got cap refs on %s\n",
+	     inode, off, (size_t)PAGE_CACHE_SIZE, ceph_cap_string(got));
+
+	if ((got & (CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO)) ||
+	    ci->i_inline_version == CEPH_INLINE_NONE)
+		ret = filemap_fault(vma, vmf);
+	else
+		ret = -EAGAIN;
+
+	dout("filemap_fault %p %llu~%zd dropping cap refs on %s ret %d\n",
+	     inode, off, (size_t)PAGE_CACHE_SIZE, ceph_cap_string(got), ret);
+	if (pinned_page)
+		page_cache_release(pinned_page);
+	ceph_put_cap_refs(ci, got);
+
+	if (ret != -EAGAIN)
+		return ret;
+
+	/* read inline data */
+	if (off >= PAGE_CACHE_SIZE) {
+		/* does not support inline data > PAGE_SIZE */
+		ret = VM_FAULT_SIGBUS;
+	} else {
+		int ret1;
+		struct address_space *mapping = inode->i_mapping;
+		struct page *page = find_or_create_page(mapping, 0,
+						mapping_gfp_mask(mapping) &
+						~__GFP_FS);
+		if (!page) {
+			ret = VM_FAULT_OOM;
+			goto out;
+		}
+		ret1 = __ceph_do_getattr(inode, page,
+					 CEPH_STAT_CAP_INLINE_DATA, true);
+		if (ret1 < 0 || off >= i_size_read(inode)) {
+			unlock_page(page);
+			page_cache_release(page);
+			ret = VM_FAULT_SIGBUS;
+			goto out;
+		}
+		if (ret1 < PAGE_CACHE_SIZE)
+			zero_user_segment(page, ret1, PAGE_CACHE_SIZE);
+		else
+			flush_dcache_page(page);
+		SetPageUptodate(page);
+		vmf->page = page;
+		ret = VM_FAULT_MAJOR | VM_FAULT_LOCKED;
+	}
+out:
+	dout("filemap_fault %p %llu~%zd read inline data ret %d\n",
+	     inode, off, (size_t)PAGE_CACHE_SIZE, ret);
+	return ret;
+}
+
+/*
+ * Reuse write_begin here for simplicity.
+ */
+static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct inode *inode = file_inode(vma->vm_file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_file_info *fi = vma->vm_file->private_data;
+	struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
+	struct page *page = vmf->page;
+	loff_t off = page_offset(page);
+	loff_t size = i_size_read(inode);
+	size_t len;
+	int want, got, ret;
+
+	if (ci->i_inline_version != CEPH_INLINE_NONE) {
+		struct page *locked_page = NULL;
+		if (off == 0) {
+			lock_page(page);
+			locked_page = page;
+		}
+		ret = ceph_uninline_data(vma->vm_file, locked_page);
+		if (locked_page)
+			unlock_page(locked_page);
+		if (ret < 0)
+			return VM_FAULT_SIGBUS;
+	}
+
+	if (off + PAGE_CACHE_SIZE <= size)
+		len = PAGE_CACHE_SIZE;
+	else
+		len = size & ~PAGE_CACHE_MASK;
+
+	dout("page_mkwrite %p %llx.%llx %llu~%zd getting caps i_size %llu\n",
+	     inode, ceph_vinop(inode), off, len, size);
+	if (fi->fmode & CEPH_FILE_MODE_LAZY)
+		want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
+	else
+		want = CEPH_CAP_FILE_BUFFER;
+	while (1) {
+		got = 0;
+		ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, off + len,
+				    &got, NULL);
+		if (ret == 0)
+			break;
+		if (ret != -ERESTARTSYS) {
+			WARN_ON(1);
+			return VM_FAULT_SIGBUS;
+		}
+	}
+	dout("page_mkwrite %p %llu~%zd got cap refs on %s\n",
+	     inode, off, len, ceph_cap_string(got));
+
+	/* Update time before taking page lock */
+	file_update_time(vma->vm_file);
+
+	lock_page(page);
+
+	ret = VM_FAULT_NOPAGE;
+	if ((off > size) ||
+	    (page->mapping != inode->i_mapping))
+		goto out;
+
+	ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
+	if (ret == 0) {
+		/* success.  we'll keep the page locked. */
+		set_page_dirty(page);
+		up_read(&mdsc->snap_rwsem);
+		ret = VM_FAULT_LOCKED;
+	} else {
+		if (ret == -ENOMEM)
+			ret = VM_FAULT_OOM;
+		else
+			ret = VM_FAULT_SIGBUS;
+	}
+out:
+	if (ret != VM_FAULT_LOCKED)
+		unlock_page(page);
+	if (ret == VM_FAULT_LOCKED ||
+	    ci->i_inline_version != CEPH_INLINE_NONE) {
+		int dirty;
+		spin_lock(&ci->i_ceph_lock);
+		ci->i_inline_version = CEPH_INLINE_NONE;
+		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
+		spin_unlock(&ci->i_ceph_lock);
+		if (dirty)
+			__mark_inode_dirty(inode, dirty);
+	}
+
+	dout("page_mkwrite %p %llu~%zd dropping cap refs on %s ret %d\n",
+	     inode, off, len, ceph_cap_string(got), ret);
+	ceph_put_cap_refs(ci, got);
+
+	return ret;
+}
+
+void ceph_fill_inline_data(struct inode *inode, struct page *locked_page,
+			   char	*data, size_t len)
+{
+	struct address_space *mapping = inode->i_mapping;
+	struct page *page;
+
+	if (locked_page) {
+		page = locked_page;
+	} else {
+		if (i_size_read(inode) == 0)
+			return;
+		page = find_or_create_page(mapping, 0,
+					   mapping_gfp_mask(mapping) & ~__GFP_FS);
+		if (!page)
+			return;
+		if (PageUptodate(page)) {
+			unlock_page(page);
+			page_cache_release(page);
+			return;
+		}
+	}
+
+	dout("fill_inline_data %p %llx.%llx len %zu locked_page %p\n",
+	     inode, ceph_vinop(inode), len, locked_page);
+
+	if (len > 0) {
+		void *kaddr = kmap_atomic(page);
+		memcpy(kaddr, data, len);
+		kunmap_atomic(kaddr);
+	}
+
+	if (page != locked_page) {
+		if (len < PAGE_CACHE_SIZE)
+			zero_user_segment(page, len, PAGE_CACHE_SIZE);
+		else
+			flush_dcache_page(page);
+
+		SetPageUptodate(page);
+		unlock_page(page);
+		page_cache_release(page);
+	}
+}
+
+int ceph_uninline_data(struct file *filp, struct page *locked_page)
+{
+	struct inode *inode = file_inode(filp);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_osd_request *req;
+	struct page *page = NULL;
+	u64 len, inline_version;
+	int err = 0;
+	bool from_pagecache = false;
+
+	spin_lock(&ci->i_ceph_lock);
+	inline_version = ci->i_inline_version;
+	spin_unlock(&ci->i_ceph_lock);
+
+	dout("uninline_data %p %llx.%llx inline_version %llu\n",
+	     inode, ceph_vinop(inode), inline_version);
+
+	if (inline_version == 1 || /* initial version, no data */
+	    inline_version == CEPH_INLINE_NONE)
+		goto out;
+
+	if (locked_page) {
+		page = locked_page;
+		WARN_ON(!PageUptodate(page));
+	} else if (ceph_caps_issued(ci) &
+		   (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) {
+		page = find_get_page(inode->i_mapping, 0);
+		if (page) {
+			if (PageUptodate(page)) {
+				from_pagecache = true;
+				lock_page(page);
+			} else {
+				page_cache_release(page);
+				page = NULL;
+			}
+		}
+	}
+
+	if (page) {
+		len = i_size_read(inode);
+		if (len > PAGE_CACHE_SIZE)
+			len = PAGE_CACHE_SIZE;
+	} else {
+		page = __page_cache_alloc(GFP_NOFS);
+		if (!page) {
+			err = -ENOMEM;
+			goto out;
+		}
+		err = __ceph_do_getattr(inode, page,
+					CEPH_STAT_CAP_INLINE_DATA, true);
+		if (err < 0) {
+			/* no inline data */
+			if (err == -ENODATA)
+				err = 0;
+			goto out;
+		}
+		len = err;
+	}
+
+	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
+				    ceph_vino(inode), 0, &len, 0, 1,
+				    CEPH_OSD_OP_CREATE,
+				    CEPH_OSD_FLAG_ONDISK | CEPH_OSD_FLAG_WRITE,
+				    ci->i_snap_realm->cached_context,
+				    0, 0, false);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+
+	ceph_osdc_build_request(req, 0, NULL, CEPH_NOSNAP, &inode->i_mtime);
+	err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
+	if (!err)
+		err = ceph_osdc_wait_request(&fsc->client->osdc, req);
+	ceph_osdc_put_request(req);
+	if (err < 0)
+		goto out;
+
+	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
+				    ceph_vino(inode), 0, &len, 1, 3,
+				    CEPH_OSD_OP_WRITE,
+				    CEPH_OSD_FLAG_ONDISK | CEPH_OSD_FLAG_WRITE,
+				    ci->i_snap_realm->cached_context,
+				    ci->i_truncate_seq, ci->i_truncate_size,
+				    false);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+
+	osd_req_op_extent_osd_data_pages(req, 1, &page, len, 0, false, false);
+
+	{
+		__le64 xattr_buf = cpu_to_le64(inline_version);
+		err = osd_req_op_xattr_init(req, 0, CEPH_OSD_OP_CMPXATTR,
+					    "inline_version", &xattr_buf,
+					    sizeof(xattr_buf),
+					    CEPH_OSD_CMPXATTR_OP_GT,
+					    CEPH_OSD_CMPXATTR_MODE_U64);
+		if (err)
+			goto out_put;
+	}
+
+	{
+		char xattr_buf[32];
+		int xattr_len = snprintf(xattr_buf, sizeof(xattr_buf),
+					 "%llu", inline_version);
+		err = osd_req_op_xattr_init(req, 2, CEPH_OSD_OP_SETXATTR,
+					    "inline_version",
+					    xattr_buf, xattr_len, 0, 0);
+		if (err)
+			goto out_put;
+	}
+
+	ceph_osdc_build_request(req, 0, NULL, CEPH_NOSNAP, &inode->i_mtime);
+	err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
+	if (!err)
+		err = ceph_osdc_wait_request(&fsc->client->osdc, req);
+out_put:
+	ceph_osdc_put_request(req);
+	if (err == -ECANCELED)
+		err = 0;
+out:
+	if (page && page != locked_page) {
+		if (from_pagecache) {
+			unlock_page(page);
+			page_cache_release(page);
+		} else
+			__free_pages(page, 0);
+	}
+
+	dout("uninline_data %p %llx.%llx inline_version %llu = %d\n",
+	     inode, ceph_vinop(inode), inline_version, err);
+	return err;
+}
+
+static struct vm_operations_struct ceph_vmops = {
+	.fault		= ceph_filemap_fault,
+	.page_mkwrite	= ceph_page_mkwrite,
+};
+
+int ceph_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct address_space *mapping = file->f_mapping;
+
+	if (!mapping->a_ops->readpage)
+		return -ENOEXEC;
+	file_accessed(file);
+	vma->vm_ops = &ceph_vmops;
+	return 0;
+}
diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c
new file mode 100644
index 000000000..834f9f372
--- /dev/null
+++ b/fs/ceph/cache.c
@@ -0,0 +1,402 @@
+/*
+ * Ceph cache definitions.
+ *
+ *  Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
+ *  Written by Milosz Tanski (milosz@adfin.com)
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include "super.h"
+#include "cache.h"
+
+struct ceph_aux_inode {
+	struct timespec	mtime;
+	loff_t          size;
+};
+
+struct fscache_netfs ceph_cache_netfs = {
+	.name		= "ceph",
+	.version	= 0,
+};
+
+static uint16_t ceph_fscache_session_get_key(const void *cookie_netfs_data,
+					     void *buffer, uint16_t maxbuf)
+{
+	const struct ceph_fs_client* fsc = cookie_netfs_data;
+	uint16_t klen;
+
+	klen = sizeof(fsc->client->fsid);
+	if (klen > maxbuf)
+		return 0;
+
+	memcpy(buffer, &fsc->client->fsid, klen);
+	return klen;
+}
+
+static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
+	.name		= "CEPH.fsid",
+	.type		= FSCACHE_COOKIE_TYPE_INDEX,
+	.get_key	= ceph_fscache_session_get_key,
+};
+
+int ceph_fscache_register(void)
+{
+	return fscache_register_netfs(&ceph_cache_netfs);
+}
+
+void ceph_fscache_unregister(void)
+{
+	fscache_unregister_netfs(&ceph_cache_netfs);
+}
+
+int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
+{
+	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
+					      &ceph_fscache_fsid_object_def,
+					      fsc, true);
+
+	if (fsc->fscache == NULL) {
+		pr_err("Unable to resgister fsid: %p fscache cookie", fsc);
+		return 0;
+	}
+
+	fsc->revalidate_wq = alloc_workqueue("ceph-revalidate", 0, 1);
+	if (fsc->revalidate_wq == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static uint16_t ceph_fscache_inode_get_key(const void *cookie_netfs_data,
+					   void *buffer, uint16_t maxbuf)
+{
+	const struct ceph_inode_info* ci = cookie_netfs_data;
+	uint16_t klen;
+
+	/* use ceph virtual inode (id + snaphot) */
+	klen = sizeof(ci->i_vino);
+	if (klen > maxbuf)
+		return 0;
+
+	memcpy(buffer, &ci->i_vino, klen);
+	return klen;
+}
+
+static uint16_t ceph_fscache_inode_get_aux(const void *cookie_netfs_data,
+					   void *buffer, uint16_t bufmax)
+{
+	struct ceph_aux_inode aux;
+	const struct ceph_inode_info* ci = cookie_netfs_data;
+	const struct inode* inode = &ci->vfs_inode;
+
+	memset(&aux, 0, sizeof(aux));
+	aux.mtime = inode->i_mtime;
+	aux.size = inode->i_size;
+
+	memcpy(buffer, &aux, sizeof(aux));
+
+	return sizeof(aux);
+}
+
+static void ceph_fscache_inode_get_attr(const void *cookie_netfs_data,
+					uint64_t *size)
+{
+	const struct ceph_inode_info* ci = cookie_netfs_data;
+	const struct inode* inode = &ci->vfs_inode;
+
+	*size = inode->i_size;
+}
+
+static enum fscache_checkaux ceph_fscache_inode_check_aux(
+	void *cookie_netfs_data, const void *data, uint16_t dlen)
+{
+	struct ceph_aux_inode aux;
+	struct ceph_inode_info* ci = cookie_netfs_data;
+	struct inode* inode = &ci->vfs_inode;
+
+	if (dlen != sizeof(aux))
+		return FSCACHE_CHECKAUX_OBSOLETE;
+
+	memset(&aux, 0, sizeof(aux));
+	aux.mtime = inode->i_mtime;
+	aux.size = inode->i_size;
+
+	if (memcmp(data, &aux, sizeof(aux)) != 0)
+		return FSCACHE_CHECKAUX_OBSOLETE;
+
+	dout("ceph inode 0x%p cached okay", ci);
+	return FSCACHE_CHECKAUX_OKAY;
+}
+
+static void ceph_fscache_inode_now_uncached(void* cookie_netfs_data)
+{
+	struct ceph_inode_info* ci = cookie_netfs_data;
+	struct pagevec pvec;
+	pgoff_t first;
+	int loop, nr_pages;
+
+	pagevec_init(&pvec, 0);
+	first = 0;
+
+	dout("ceph inode 0x%p now uncached", ci);
+
+	while (1) {
+		nr_pages = pagevec_lookup(&pvec, ci->vfs_inode.i_mapping, first,
+					  PAGEVEC_SIZE - pagevec_count(&pvec));
+
+		if (!nr_pages)
+			break;
+
+		for (loop = 0; loop < nr_pages; loop++)
+			ClearPageFsCache(pvec.pages[loop]);
+
+		first = pvec.pages[nr_pages - 1]->index + 1;
+
+		pvec.nr = nr_pages;
+		pagevec_release(&pvec);
+		cond_resched();
+	}
+}
+
+static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
+	.name		= "CEPH.inode",
+	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
+	.get_key	= ceph_fscache_inode_get_key,
+	.get_attr	= ceph_fscache_inode_get_attr,
+	.get_aux	= ceph_fscache_inode_get_aux,
+	.check_aux	= ceph_fscache_inode_check_aux,
+	.now_uncached	= ceph_fscache_inode_now_uncached,
+};
+
+void ceph_fscache_register_inode_cookie(struct ceph_fs_client* fsc,
+					struct ceph_inode_info* ci)
+{
+	struct inode* inode = &ci->vfs_inode;
+
+	/* No caching for filesystem */
+	if (fsc->fscache == NULL)
+		return;
+
+	/* Only cache for regular files that are read only */
+	if ((ci->vfs_inode.i_mode & S_IFREG) == 0)
+		return;
+
+	/* Avoid multiple racing open requests */
+	mutex_lock(&inode->i_mutex);
+
+	if (ci->fscache)
+		goto done;
+
+	ci->fscache = fscache_acquire_cookie(fsc->fscache,
+					     &ceph_fscache_inode_object_def,
+					     ci, true);
+	fscache_check_consistency(ci->fscache);
+done:
+	mutex_unlock(&inode->i_mutex);
+
+}
+
+void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
+{
+	struct fscache_cookie* cookie;
+
+	if ((cookie = ci->fscache) == NULL)
+		return;
+
+	ci->fscache = NULL;
+
+	fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
+	fscache_relinquish_cookie(cookie, 0);
+}
+
+static void ceph_vfs_readpage_complete(struct page *page, void *data, int error)
+{
+	if (!error)
+		SetPageUptodate(page);
+}
+
+static void ceph_vfs_readpage_complete_unlock(struct page *page, void *data, int error)
+{
+	if (!error)
+		SetPageUptodate(page);
+
+	unlock_page(page);
+}
+
+static inline int cache_valid(struct ceph_inode_info *ci)
+{
+	return ((ceph_caps_issued(ci) & CEPH_CAP_FILE_CACHE) &&
+		(ci->i_fscache_gen == ci->i_rdcache_gen));
+}
+
+
+/* Atempt to read from the fscache,
+ *
+ * This function is called from the readpage_nounlock context. DO NOT attempt to
+ * unlock the page here (or in the callback).
+ */
+int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int ret;
+
+	if (!cache_valid(ci))
+		return -ENOBUFS;
+
+	ret = fscache_read_or_alloc_page(ci->fscache, page,
+					 ceph_vfs_readpage_complete, NULL,
+					 GFP_KERNEL);
+
+	switch (ret) {
+		case 0: /* Page found */
+			dout("page read submitted\n");
+			return 0;
+		case -ENOBUFS: /* Pages were not found, and can't be */
+		case -ENODATA: /* Pages were not found */
+			dout("page/inode not in cache\n");
+			return ret;
+		default:
+			dout("%s: unknown error ret = %i\n", __func__, ret);
+			return ret;
+	}
+}
+
+int ceph_readpages_from_fscache(struct inode *inode,
+				  struct address_space *mapping,
+				  struct list_head *pages,
+				  unsigned *nr_pages)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int ret;
+
+	if (!cache_valid(ci))
+		return -ENOBUFS;
+
+	ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
+					  ceph_vfs_readpage_complete_unlock,
+					  NULL, mapping_gfp_mask(mapping));
+
+	switch (ret) {
+		case 0: /* All pages found */
+			dout("all-page read submitted\n");
+			return 0;
+		case -ENOBUFS: /* Some pages were not found, and can't be */
+		case -ENODATA: /* some pages were not found */
+			dout("page/inode not in cache\n");
+			return ret;
+		default:
+			dout("%s: unknown error ret = %i\n", __func__, ret);
+			return ret;
+	}
+}
+
+void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int ret;
+
+	if (!PageFsCache(page))
+		return;
+
+	if (!cache_valid(ci))
+		return;
+
+	ret = fscache_write_page(ci->fscache, page, GFP_KERNEL);
+	if (ret)
+		 fscache_uncache_page(ci->fscache, page);
+}
+
+void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	if (!PageFsCache(page))
+		return;
+
+	fscache_wait_on_page_write(ci->fscache, page);
+	fscache_uncache_page(ci->fscache, page);
+}
+
+void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
+{
+	if (fsc->revalidate_wq)
+		destroy_workqueue(fsc->revalidate_wq);
+
+	fscache_relinquish_cookie(fsc->fscache, 0);
+	fsc->fscache = NULL;
+}
+
+static void ceph_revalidate_work(struct work_struct *work)
+{
+	int issued;
+	u32 orig_gen;
+	struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
+						  i_revalidate_work);
+	struct inode *inode = &ci->vfs_inode;
+
+	spin_lock(&ci->i_ceph_lock);
+	issued = __ceph_caps_issued(ci, NULL);
+	orig_gen = ci->i_rdcache_gen;
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (!(issued & CEPH_CAP_FILE_CACHE)) {
+		dout("revalidate_work lost cache before validation %p\n",
+		     inode);
+		goto out;
+	}
+
+	if (!fscache_check_consistency(ci->fscache))
+		fscache_invalidate(ci->fscache);
+
+	spin_lock(&ci->i_ceph_lock);
+	/* Update the new valid generation (backwards sanity check too) */
+	if (orig_gen > ci->i_fscache_gen) {
+		ci->i_fscache_gen = orig_gen;
+	}
+	spin_unlock(&ci->i_ceph_lock);
+
+out:
+	iput(&ci->vfs_inode);
+}
+
+void ceph_queue_revalidate(struct inode *inode)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	if (fsc->revalidate_wq == NULL || ci->fscache == NULL)
+		return;
+
+	ihold(inode);
+
+	if (queue_work(ceph_sb_to_client(inode->i_sb)->revalidate_wq,
+		       &ci->i_revalidate_work)) {
+		dout("ceph_queue_revalidate %p\n", inode);
+	} else {
+		dout("ceph_queue_revalidate %p failed\n)", inode);
+		iput(inode);
+	}
+}
+
+void ceph_fscache_inode_init(struct ceph_inode_info *ci)
+{
+	ci->fscache = NULL;
+	/* The first load is verifed cookie open time */
+	ci->i_fscache_gen = 1;
+	INIT_WORK(&ci->i_revalidate_work, ceph_revalidate_work);
+}
diff --git a/fs/ceph/cache.h b/fs/ceph/cache.h
new file mode 100644
index 000000000..5ac591bd0
--- /dev/null
+++ b/fs/ceph/cache.h
@@ -0,0 +1,182 @@
+/*
+ * Ceph cache definitions.
+ *
+ *  Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
+ *  Written by Milosz Tanski (milosz@adfin.com)
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#ifndef _CEPH_CACHE_H
+#define _CEPH_CACHE_H
+
+#ifdef CONFIG_CEPH_FSCACHE
+
+extern struct fscache_netfs ceph_cache_netfs;
+
+int ceph_fscache_register(void);
+void ceph_fscache_unregister(void);
+
+int ceph_fscache_register_fs(struct ceph_fs_client* fsc);
+void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc);
+
+void ceph_fscache_inode_init(struct ceph_inode_info *ci);
+void ceph_fscache_register_inode_cookie(struct ceph_fs_client* fsc,
+					struct ceph_inode_info* ci);
+void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci);
+
+int ceph_readpage_from_fscache(struct inode *inode, struct page *page);
+int ceph_readpages_from_fscache(struct inode *inode,
+				struct address_space *mapping,
+				struct list_head *pages,
+				unsigned *nr_pages);
+void ceph_readpage_to_fscache(struct inode *inode, struct page *page);
+void ceph_invalidate_fscache_page(struct inode* inode, struct page *page);
+void ceph_queue_revalidate(struct inode *inode);
+
+static inline void ceph_fscache_update_objectsize(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	fscache_attr_changed(ci->fscache);
+}
+
+static inline void ceph_fscache_invalidate(struct inode *inode)
+{
+	fscache_invalidate(ceph_inode(inode)->fscache);
+}
+
+static inline void ceph_fscache_uncache_page(struct inode *inode,
+					     struct page *page)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	return fscache_uncache_page(ci->fscache, page);
+}
+
+static inline int ceph_release_fscache_page(struct page *page, gfp_t gfp)
+{
+	struct inode* inode = page->mapping->host;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	return fscache_maybe_release_page(ci->fscache, page, gfp);
+}
+
+static inline void ceph_fscache_readpage_cancel(struct inode *inode,
+						struct page *page)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	if (fscache_cookie_valid(ci->fscache) && PageFsCache(page))
+		__fscache_uncache_page(ci->fscache, page);
+}
+
+static inline void ceph_fscache_readpages_cancel(struct inode *inode,
+						 struct list_head *pages)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	return fscache_readpages_cancel(ci->fscache, pages);
+}
+
+#else
+
+static inline int ceph_fscache_register(void)
+{
+	return 0;
+}
+
+static inline void ceph_fscache_unregister(void)
+{
+}
+
+static inline int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
+{
+	return 0;
+}
+
+static inline void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
+{
+}
+
+static inline void ceph_fscache_inode_init(struct ceph_inode_info *ci)
+{
+}
+
+static inline void ceph_fscache_register_inode_cookie(struct ceph_fs_client* parent_fsc,
+						      struct ceph_inode_info* ci)
+{
+}
+
+static inline void ceph_fscache_uncache_page(struct inode *inode,
+					     struct page *pages)
+{
+}
+
+static inline int ceph_readpage_from_fscache(struct inode* inode,
+					     struct page *page)
+{
+	return -ENOBUFS;
+}
+
+static inline int ceph_readpages_from_fscache(struct inode *inode,
+					      struct address_space *mapping,
+					      struct list_head *pages,
+					      unsigned *nr_pages)
+{
+	return -ENOBUFS;
+}
+
+static inline void ceph_readpage_to_fscache(struct inode *inode,
+					    struct page *page)
+{
+}
+
+static inline void ceph_fscache_update_objectsize(struct inode *inode)
+{
+}
+
+static inline void ceph_fscache_invalidate(struct inode *inode)
+{
+}
+
+static inline void ceph_invalidate_fscache_page(struct inode *inode,
+						struct page *page)
+{
+}
+
+static inline void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
+{
+}
+
+static inline int ceph_release_fscache_page(struct page *page, gfp_t gfp)
+{
+	return 1;
+}
+
+static inline void ceph_fscache_readpage_cancel(struct inode *inode,
+						struct page *page)
+{
+}
+
+static inline void ceph_fscache_readpages_cancel(struct inode *inode,
+						 struct list_head *pages)
+{
+}
+
+static inline void ceph_queue_revalidate(struct inode *inode)
+{
+}
+
+#endif
+
+#endif
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
new file mode 100644
index 000000000..be5ea6af8
--- /dev/null
+++ b/fs/ceph/caps.c
@@ -0,0 +1,3456 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+#include <linux/writeback.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include "cache.h"
+#include <linux/ceph/decode.h>
+#include <linux/ceph/messenger.h>
+
+/*
+ * Capability management
+ *
+ * The Ceph metadata servers control client access to inode metadata
+ * and file data by issuing capabilities, granting clients permission
+ * to read and/or write both inode field and file data to OSDs
+ * (storage nodes).  Each capability consists of a set of bits
+ * indicating which operations are allowed.
+ *
+ * If the client holds a *_SHARED cap, the client has a coherent value
+ * that can be safely read from the cached inode.
+ *
+ * In the case of a *_EXCL (exclusive) or FILE_WR capabilities, the
+ * client is allowed to change inode attributes (e.g., file size,
+ * mtime), note its dirty state in the ceph_cap, and asynchronously
+ * flush that metadata change to the MDS.
+ *
+ * In the event of a conflicting operation (perhaps by another
+ * client), the MDS will revoke the conflicting client capabilities.
+ *
+ * In order for a client to cache an inode, it must hold a capability
+ * with at least one MDS server.  When inodes are released, release
+ * notifications are batched and periodically sent en masse to the MDS
+ * cluster to release server state.
+ */
+
+
+/*
+ * Generate readable cap strings for debugging output.
+ */
+#define MAX_CAP_STR 20
+static char cap_str[MAX_CAP_STR][40];
+static DEFINE_SPINLOCK(cap_str_lock);
+static int last_cap_str;
+
+static char *gcap_string(char *s, int c)
+{
+	if (c & CEPH_CAP_GSHARED)
+		*s++ = 's';
+	if (c & CEPH_CAP_GEXCL)
+		*s++ = 'x';
+	if (c & CEPH_CAP_GCACHE)
+		*s++ = 'c';
+	if (c & CEPH_CAP_GRD)
+		*s++ = 'r';
+	if (c & CEPH_CAP_GWR)
+		*s++ = 'w';
+	if (c & CEPH_CAP_GBUFFER)
+		*s++ = 'b';
+	if (c & CEPH_CAP_GLAZYIO)
+		*s++ = 'l';
+	return s;
+}
+
+const char *ceph_cap_string(int caps)
+{
+	int i;
+	char *s;
+	int c;
+
+	spin_lock(&cap_str_lock);
+	i = last_cap_str++;
+	if (last_cap_str == MAX_CAP_STR)
+		last_cap_str = 0;
+	spin_unlock(&cap_str_lock);
+
+	s = cap_str[i];
+
+	if (caps & CEPH_CAP_PIN)
+		*s++ = 'p';
+
+	c = (caps >> CEPH_CAP_SAUTH) & 3;
+	if (c) {
+		*s++ = 'A';
+		s = gcap_string(s, c);
+	}
+
+	c = (caps >> CEPH_CAP_SLINK) & 3;
+	if (c) {
+		*s++ = 'L';
+		s = gcap_string(s, c);
+	}
+
+	c = (caps >> CEPH_CAP_SXATTR) & 3;
+	if (c) {
+		*s++ = 'X';
+		s = gcap_string(s, c);
+	}
+
+	c = caps >> CEPH_CAP_SFILE;
+	if (c) {
+		*s++ = 'F';
+		s = gcap_string(s, c);
+	}
+
+	if (s == cap_str[i])
+		*s++ = '-';
+	*s = 0;
+	return cap_str[i];
+}
+
+void ceph_caps_init(struct ceph_mds_client *mdsc)
+{
+	INIT_LIST_HEAD(&mdsc->caps_list);
+	spin_lock_init(&mdsc->caps_list_lock);
+}
+
+void ceph_caps_finalize(struct ceph_mds_client *mdsc)
+{
+	struct ceph_cap *cap;
+
+	spin_lock(&mdsc->caps_list_lock);
+	while (!list_empty(&mdsc->caps_list)) {
+		cap = list_first_entry(&mdsc->caps_list,
+				       struct ceph_cap, caps_item);
+		list_del(&cap->caps_item);
+		kmem_cache_free(ceph_cap_cachep, cap);
+	}
+	mdsc->caps_total_count = 0;
+	mdsc->caps_avail_count = 0;
+	mdsc->caps_use_count = 0;
+	mdsc->caps_reserve_count = 0;
+	mdsc->caps_min_count = 0;
+	spin_unlock(&mdsc->caps_list_lock);
+}
+
+void ceph_adjust_min_caps(struct ceph_mds_client *mdsc, int delta)
+{
+	spin_lock(&mdsc->caps_list_lock);
+	mdsc->caps_min_count += delta;
+	BUG_ON(mdsc->caps_min_count < 0);
+	spin_unlock(&mdsc->caps_list_lock);
+}
+
+void ceph_reserve_caps(struct ceph_mds_client *mdsc,
+		      struct ceph_cap_reservation *ctx, int need)
+{
+	int i;
+	struct ceph_cap *cap;
+	int have;
+	int alloc = 0;
+	LIST_HEAD(newcaps);
+
+	dout("reserve caps ctx=%p need=%d\n", ctx, need);
+
+	/* first reserve any caps that are already allocated */
+	spin_lock(&mdsc->caps_list_lock);
+	if (mdsc->caps_avail_count >= need)
+		have = need;
+	else
+		have = mdsc->caps_avail_count;
+	mdsc->caps_avail_count -= have;
+	mdsc->caps_reserve_count += have;
+	BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
+					 mdsc->caps_reserve_count +
+					 mdsc->caps_avail_count);
+	spin_unlock(&mdsc->caps_list_lock);
+
+	for (i = have; i < need; i++) {
+		cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
+		if (!cap)
+			break;
+		list_add(&cap->caps_item, &newcaps);
+		alloc++;
+	}
+	/* we didn't manage to reserve as much as we needed */
+	if (have + alloc != need)
+		pr_warn("reserve caps ctx=%p ENOMEM need=%d got=%d\n",
+			ctx, need, have + alloc);
+
+	spin_lock(&mdsc->caps_list_lock);
+	mdsc->caps_total_count += alloc;
+	mdsc->caps_reserve_count += alloc;
+	list_splice(&newcaps, &mdsc->caps_list);
+
+	BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
+					 mdsc->caps_reserve_count +
+					 mdsc->caps_avail_count);
+	spin_unlock(&mdsc->caps_list_lock);
+
+	ctx->count = need;
+	dout("reserve caps ctx=%p %d = %d used + %d resv + %d avail\n",
+	     ctx, mdsc->caps_total_count, mdsc->caps_use_count,
+	     mdsc->caps_reserve_count, mdsc->caps_avail_count);
+}
+
+int ceph_unreserve_caps(struct ceph_mds_client *mdsc,
+			struct ceph_cap_reservation *ctx)
+{
+	dout("unreserve caps ctx=%p count=%d\n", ctx, ctx->count);
+	if (ctx->count) {
+		spin_lock(&mdsc->caps_list_lock);
+		BUG_ON(mdsc->caps_reserve_count < ctx->count);
+		mdsc->caps_reserve_count -= ctx->count;
+		mdsc->caps_avail_count += ctx->count;
+		ctx->count = 0;
+		dout("unreserve caps %d = %d used + %d resv + %d avail\n",
+		     mdsc->caps_total_count, mdsc->caps_use_count,
+		     mdsc->caps_reserve_count, mdsc->caps_avail_count);
+		BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
+						 mdsc->caps_reserve_count +
+						 mdsc->caps_avail_count);
+		spin_unlock(&mdsc->caps_list_lock);
+	}
+	return 0;
+}
+
+struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
+			      struct ceph_cap_reservation *ctx)
+{
+	struct ceph_cap *cap = NULL;
+
+	/* temporary, until we do something about cap import/export */
+	if (!ctx) {
+		cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
+		if (cap) {
+			spin_lock(&mdsc->caps_list_lock);
+			mdsc->caps_use_count++;
+			mdsc->caps_total_count++;
+			spin_unlock(&mdsc->caps_list_lock);
+		}
+		return cap;
+	}
+
+	spin_lock(&mdsc->caps_list_lock);
+	dout("get_cap ctx=%p (%d) %d = %d used + %d resv + %d avail\n",
+	     ctx, ctx->count, mdsc->caps_total_count, mdsc->caps_use_count,
+	     mdsc->caps_reserve_count, mdsc->caps_avail_count);
+	BUG_ON(!ctx->count);
+	BUG_ON(ctx->count > mdsc->caps_reserve_count);
+	BUG_ON(list_empty(&mdsc->caps_list));
+
+	ctx->count--;
+	mdsc->caps_reserve_count--;
+	mdsc->caps_use_count++;
+
+	cap = list_first_entry(&mdsc->caps_list, struct ceph_cap, caps_item);
+	list_del(&cap->caps_item);
+
+	BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
+	       mdsc->caps_reserve_count + mdsc->caps_avail_count);
+	spin_unlock(&mdsc->caps_list_lock);
+	return cap;
+}
+
+void ceph_put_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap)
+{
+	spin_lock(&mdsc->caps_list_lock);
+	dout("put_cap %p %d = %d used + %d resv + %d avail\n",
+	     cap, mdsc->caps_total_count, mdsc->caps_use_count,
+	     mdsc->caps_reserve_count, mdsc->caps_avail_count);
+	mdsc->caps_use_count--;
+	/*
+	 * Keep some preallocated caps around (ceph_min_count), to
+	 * avoid lots of free/alloc churn.
+	 */
+	if (mdsc->caps_avail_count >= mdsc->caps_reserve_count +
+				      mdsc->caps_min_count) {
+		mdsc->caps_total_count--;
+		kmem_cache_free(ceph_cap_cachep, cap);
+	} else {
+		mdsc->caps_avail_count++;
+		list_add(&cap->caps_item, &mdsc->caps_list);
+	}
+
+	BUG_ON(mdsc->caps_total_count != mdsc->caps_use_count +
+	       mdsc->caps_reserve_count + mdsc->caps_avail_count);
+	spin_unlock(&mdsc->caps_list_lock);
+}
+
+void ceph_reservation_status(struct ceph_fs_client *fsc,
+			     int *total, int *avail, int *used, int *reserved,
+			     int *min)
+{
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+
+	if (total)
+		*total = mdsc->caps_total_count;
+	if (avail)
+		*avail = mdsc->caps_avail_count;
+	if (used)
+		*used = mdsc->caps_use_count;
+	if (reserved)
+		*reserved = mdsc->caps_reserve_count;
+	if (min)
+		*min = mdsc->caps_min_count;
+}
+
+/*
+ * Find ceph_cap for given mds, if any.
+ *
+ * Called with i_ceph_lock held.
+ */
+static struct ceph_cap *__get_cap_for_mds(struct ceph_inode_info *ci, int mds)
+{
+	struct ceph_cap *cap;
+	struct rb_node *n = ci->i_caps.rb_node;
+
+	while (n) {
+		cap = rb_entry(n, struct ceph_cap, ci_node);
+		if (mds < cap->mds)
+			n = n->rb_left;
+		else if (mds > cap->mds)
+			n = n->rb_right;
+		else
+			return cap;
+	}
+	return NULL;
+}
+
+struct ceph_cap *ceph_get_cap_for_mds(struct ceph_inode_info *ci, int mds)
+{
+	struct ceph_cap *cap;
+
+	spin_lock(&ci->i_ceph_lock);
+	cap = __get_cap_for_mds(ci, mds);
+	spin_unlock(&ci->i_ceph_lock);
+	return cap;
+}
+
+/*
+ * Return id of any MDS with a cap, preferably FILE_WR|BUFFER|EXCL, else -1.
+ */
+static int __ceph_get_cap_mds(struct ceph_inode_info *ci)
+{
+	struct ceph_cap *cap;
+	int mds = -1;
+	struct rb_node *p;
+
+	/* prefer mds with WR|BUFFER|EXCL caps */
+	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
+		cap = rb_entry(p, struct ceph_cap, ci_node);
+		mds = cap->mds;
+		if (cap->issued & (CEPH_CAP_FILE_WR |
+				   CEPH_CAP_FILE_BUFFER |
+				   CEPH_CAP_FILE_EXCL))
+			break;
+	}
+	return mds;
+}
+
+int ceph_get_cap_mds(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int mds;
+	spin_lock(&ci->i_ceph_lock);
+	mds = __ceph_get_cap_mds(ceph_inode(inode));
+	spin_unlock(&ci->i_ceph_lock);
+	return mds;
+}
+
+/*
+ * Called under i_ceph_lock.
+ */
+static void __insert_cap_node(struct ceph_inode_info *ci,
+			      struct ceph_cap *new)
+{
+	struct rb_node **p = &ci->i_caps.rb_node;
+	struct rb_node *parent = NULL;
+	struct ceph_cap *cap = NULL;
+
+	while (*p) {
+		parent = *p;
+		cap = rb_entry(parent, struct ceph_cap, ci_node);
+		if (new->mds < cap->mds)
+			p = &(*p)->rb_left;
+		else if (new->mds > cap->mds)
+			p = &(*p)->rb_right;
+		else
+			BUG();
+	}
+
+	rb_link_node(&new->ci_node, parent, p);
+	rb_insert_color(&new->ci_node, &ci->i_caps);
+}
+
+/*
+ * (re)set cap hold timeouts, which control the delayed release
+ * of unused caps back to the MDS.  Should be called on cap use.
+ */
+static void __cap_set_timeouts(struct ceph_mds_client *mdsc,
+			       struct ceph_inode_info *ci)
+{
+	struct ceph_mount_options *ma = mdsc->fsc->mount_options;
+
+	ci->i_hold_caps_min = round_jiffies(jiffies +
+					    ma->caps_wanted_delay_min * HZ);
+	ci->i_hold_caps_max = round_jiffies(jiffies +
+					    ma->caps_wanted_delay_max * HZ);
+	dout("__cap_set_timeouts %p min %lu max %lu\n", &ci->vfs_inode,
+	     ci->i_hold_caps_min - jiffies, ci->i_hold_caps_max - jiffies);
+}
+
+/*
+ * (Re)queue cap at the end of the delayed cap release list.
+ *
+ * If I_FLUSH is set, leave the inode at the front of the list.
+ *
+ * Caller holds i_ceph_lock
+ *    -> we take mdsc->cap_delay_lock
+ */
+static void __cap_delay_requeue(struct ceph_mds_client *mdsc,
+				struct ceph_inode_info *ci)
+{
+	__cap_set_timeouts(mdsc, ci);
+	dout("__cap_delay_requeue %p flags %d at %lu\n", &ci->vfs_inode,
+	     ci->i_ceph_flags, ci->i_hold_caps_max);
+	if (!mdsc->stopping) {
+		spin_lock(&mdsc->cap_delay_lock);
+		if (!list_empty(&ci->i_cap_delay_list)) {
+			if (ci->i_ceph_flags & CEPH_I_FLUSH)
+				goto no_change;
+			list_del_init(&ci->i_cap_delay_list);
+		}
+		list_add_tail(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
+no_change:
+		spin_unlock(&mdsc->cap_delay_lock);
+	}
+}
+
+/*
+ * Queue an inode for immediate writeback.  Mark inode with I_FLUSH,
+ * indicating we should send a cap message to flush dirty metadata
+ * asap, and move to the front of the delayed cap list.
+ */
+static void __cap_delay_requeue_front(struct ceph_mds_client *mdsc,
+				      struct ceph_inode_info *ci)
+{
+	dout("__cap_delay_requeue_front %p\n", &ci->vfs_inode);
+	spin_lock(&mdsc->cap_delay_lock);
+	ci->i_ceph_flags |= CEPH_I_FLUSH;
+	if (!list_empty(&ci->i_cap_delay_list))
+		list_del_init(&ci->i_cap_delay_list);
+	list_add(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
+	spin_unlock(&mdsc->cap_delay_lock);
+}
+
+/*
+ * Cancel delayed work on cap.
+ *
+ * Caller must hold i_ceph_lock.
+ */
+static void __cap_delay_cancel(struct ceph_mds_client *mdsc,
+			       struct ceph_inode_info *ci)
+{
+	dout("__cap_delay_cancel %p\n", &ci->vfs_inode);
+	if (list_empty(&ci->i_cap_delay_list))
+		return;
+	spin_lock(&mdsc->cap_delay_lock);
+	list_del_init(&ci->i_cap_delay_list);
+	spin_unlock(&mdsc->cap_delay_lock);
+}
+
+/*
+ * Common issue checks for add_cap, handle_cap_grant.
+ */
+static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
+			      unsigned issued)
+{
+	unsigned had = __ceph_caps_issued(ci, NULL);
+
+	/*
+	 * Each time we receive FILE_CACHE anew, we increment
+	 * i_rdcache_gen.
+	 */
+	if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
+	    (had & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0) {
+		ci->i_rdcache_gen++;
+	}
+
+	/*
+	 * if we are newly issued FILE_SHARED, mark dir not complete; we
+	 * don't know what happened to this directory while we didn't
+	 * have the cap.
+	 */
+	if ((issued & CEPH_CAP_FILE_SHARED) &&
+	    (had & CEPH_CAP_FILE_SHARED) == 0) {
+		ci->i_shared_gen++;
+		if (S_ISDIR(ci->vfs_inode.i_mode)) {
+			dout(" marking %p NOT complete\n", &ci->vfs_inode);
+			__ceph_dir_clear_complete(ci);
+		}
+	}
+}
+
+/*
+ * Add a capability under the given MDS session.
+ *
+ * Caller should hold session snap_rwsem (read) and s_mutex.
+ *
+ * @fmode is the open file mode, if we are opening a file, otherwise
+ * it is < 0.  (This is so we can atomically add the cap and add an
+ * open file reference to it.)
+ */
+void ceph_add_cap(struct inode *inode,
+		  struct ceph_mds_session *session, u64 cap_id,
+		  int fmode, unsigned issued, unsigned wanted,
+		  unsigned seq, unsigned mseq, u64 realmino, int flags,
+		  struct ceph_cap **new_cap)
+{
+	struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_cap *cap;
+	int mds = session->s_mds;
+	int actual_wanted;
+
+	dout("add_cap %p mds%d cap %llx %s seq %d\n", inode,
+	     session->s_mds, cap_id, ceph_cap_string(issued), seq);
+
+	/*
+	 * If we are opening the file, include file mode wanted bits
+	 * in wanted.
+	 */
+	if (fmode >= 0)
+		wanted |= ceph_caps_for_mode(fmode);
+
+	cap = __get_cap_for_mds(ci, mds);
+	if (!cap) {
+		cap = *new_cap;
+		*new_cap = NULL;
+
+		cap->issued = 0;
+		cap->implemented = 0;
+		cap->mds = mds;
+		cap->mds_wanted = 0;
+		cap->mseq = 0;
+
+		cap->ci = ci;
+		__insert_cap_node(ci, cap);
+
+		/* add to session cap list */
+		cap->session = session;
+		spin_lock(&session->s_cap_lock);
+		list_add_tail(&cap->session_caps, &session->s_caps);
+		session->s_nr_caps++;
+		spin_unlock(&session->s_cap_lock);
+	} else {
+		/*
+		 * auth mds of the inode changed. we received the cap export
+		 * message, but still haven't received the cap import message.
+		 * handle_cap_export() updated the new auth MDS' cap.
+		 *
+		 * "ceph_seq_cmp(seq, cap->seq) <= 0" means we are processing
+		 * a message that was send before the cap import message. So
+		 * don't remove caps.
+		 */
+		if (ceph_seq_cmp(seq, cap->seq) <= 0) {
+			WARN_ON(cap != ci->i_auth_cap);
+			WARN_ON(cap->cap_id != cap_id);
+			seq = cap->seq;
+			mseq = cap->mseq;
+			issued |= cap->issued;
+			flags |= CEPH_CAP_FLAG_AUTH;
+		}
+	}
+
+	if (!ci->i_snap_realm) {
+		/*
+		 * add this inode to the appropriate snap realm
+		 */
+		struct ceph_snap_realm *realm = ceph_lookup_snap_realm(mdsc,
+							       realmino);
+		if (realm) {
+			spin_lock(&realm->inodes_with_caps_lock);
+			ci->i_snap_realm = realm;
+			list_add(&ci->i_snap_realm_item,
+				 &realm->inodes_with_caps);
+			spin_unlock(&realm->inodes_with_caps_lock);
+		} else {
+			pr_err("ceph_add_cap: couldn't find snap realm %llx\n",
+			       realmino);
+			WARN_ON(!realm);
+		}
+	}
+
+	__check_cap_issue(ci, cap, issued);
+
+	/*
+	 * If we are issued caps we don't want, or the mds' wanted
+	 * value appears to be off, queue a check so we'll release
+	 * later and/or update the mds wanted value.
+	 */
+	actual_wanted = __ceph_caps_wanted(ci);
+	if ((wanted & ~actual_wanted) ||
+	    (issued & ~actual_wanted & CEPH_CAP_ANY_WR)) {
+		dout(" issued %s, mds wanted %s, actual %s, queueing\n",
+		     ceph_cap_string(issued), ceph_cap_string(wanted),
+		     ceph_cap_string(actual_wanted));
+		__cap_delay_requeue(mdsc, ci);
+	}
+
+	if (flags & CEPH_CAP_FLAG_AUTH) {
+		if (ci->i_auth_cap == NULL ||
+		    ceph_seq_cmp(ci->i_auth_cap->mseq, mseq) < 0) {
+			ci->i_auth_cap = cap;
+			cap->mds_wanted = wanted;
+		}
+	} else {
+		WARN_ON(ci->i_auth_cap == cap);
+	}
+
+	dout("add_cap inode %p (%llx.%llx) cap %p %s now %s seq %d mds%d\n",
+	     inode, ceph_vinop(inode), cap, ceph_cap_string(issued),
+	     ceph_cap_string(issued|cap->issued), seq, mds);
+	cap->cap_id = cap_id;
+	cap->issued = issued;
+	cap->implemented |= issued;
+	if (ceph_seq_cmp(mseq, cap->mseq) > 0)
+		cap->mds_wanted = wanted;
+	else
+		cap->mds_wanted |= wanted;
+	cap->seq = seq;
+	cap->issue_seq = seq;
+	cap->mseq = mseq;
+	cap->cap_gen = session->s_cap_gen;
+
+	if (fmode >= 0)
+		__ceph_get_fmode(ci, fmode);
+}
+
+/*
+ * Return true if cap has not timed out and belongs to the current
+ * generation of the MDS session (i.e. has not gone 'stale' due to
+ * us losing touch with the mds).
+ */
+static int __cap_is_valid(struct ceph_cap *cap)
+{
+	unsigned long ttl;
+	u32 gen;
+
+	spin_lock(&cap->session->s_gen_ttl_lock);
+	gen = cap->session->s_cap_gen;
+	ttl = cap->session->s_cap_ttl;
+	spin_unlock(&cap->session->s_gen_ttl_lock);
+
+	if (cap->cap_gen < gen || time_after_eq(jiffies, ttl)) {
+		dout("__cap_is_valid %p cap %p issued %s "
+		     "but STALE (gen %u vs %u)\n", &cap->ci->vfs_inode,
+		     cap, ceph_cap_string(cap->issued), cap->cap_gen, gen);
+		return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * Return set of valid cap bits issued to us.  Note that caps time
+ * out, and may be invalidated in bulk if the client session times out
+ * and session->s_cap_gen is bumped.
+ */
+int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented)
+{
+	int have = ci->i_snap_caps;
+	struct ceph_cap *cap;
+	struct rb_node *p;
+
+	if (implemented)
+		*implemented = 0;
+	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
+		cap = rb_entry(p, struct ceph_cap, ci_node);
+		if (!__cap_is_valid(cap))
+			continue;
+		dout("__ceph_caps_issued %p cap %p issued %s\n",
+		     &ci->vfs_inode, cap, ceph_cap_string(cap->issued));
+		have |= cap->issued;
+		if (implemented)
+			*implemented |= cap->implemented;
+	}
+	/*
+	 * exclude caps issued by non-auth MDS, but are been revoking
+	 * by the auth MDS. The non-auth MDS should be revoking/exporting
+	 * these caps, but the message is delayed.
+	 */
+	if (ci->i_auth_cap) {
+		cap = ci->i_auth_cap;
+		have &= ~cap->implemented | cap->issued;
+	}
+	return have;
+}
+
+/*
+ * Get cap bits issued by caps other than @ocap
+ */
+int __ceph_caps_issued_other(struct ceph_inode_info *ci, struct ceph_cap *ocap)
+{
+	int have = ci->i_snap_caps;
+	struct ceph_cap *cap;
+	struct rb_node *p;
+
+	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
+		cap = rb_entry(p, struct ceph_cap, ci_node);
+		if (cap == ocap)
+			continue;
+		if (!__cap_is_valid(cap))
+			continue;
+		have |= cap->issued;
+	}
+	return have;
+}
+
+/*
+ * Move a cap to the end of the LRU (oldest caps at list head, newest
+ * at list tail).
+ */
+static void __touch_cap(struct ceph_cap *cap)
+{
+	struct ceph_mds_session *s = cap->session;
+
+	spin_lock(&s->s_cap_lock);
+	if (s->s_cap_iterator == NULL) {
+		dout("__touch_cap %p cap %p mds%d\n", &cap->ci->vfs_inode, cap,
+		     s->s_mds);
+		list_move_tail(&cap->session_caps, &s->s_caps);
+	} else {
+		dout("__touch_cap %p cap %p mds%d NOP, iterating over caps\n",
+		     &cap->ci->vfs_inode, cap, s->s_mds);
+	}
+	spin_unlock(&s->s_cap_lock);
+}
+
+/*
+ * Check if we hold the given mask.  If so, move the cap(s) to the
+ * front of their respective LRUs.  (This is the preferred way for
+ * callers to check for caps they want.)
+ */
+int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
+{
+	struct ceph_cap *cap;
+	struct rb_node *p;
+	int have = ci->i_snap_caps;
+
+	if ((have & mask) == mask) {
+		dout("__ceph_caps_issued_mask %p snap issued %s"
+		     " (mask %s)\n", &ci->vfs_inode,
+		     ceph_cap_string(have),
+		     ceph_cap_string(mask));
+		return 1;
+	}
+
+	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
+		cap = rb_entry(p, struct ceph_cap, ci_node);
+		if (!__cap_is_valid(cap))
+			continue;
+		if ((cap->issued & mask) == mask) {
+			dout("__ceph_caps_issued_mask %p cap %p issued %s"
+			     " (mask %s)\n", &ci->vfs_inode, cap,
+			     ceph_cap_string(cap->issued),
+			     ceph_cap_string(mask));
+			if (touch)
+				__touch_cap(cap);
+			return 1;
+		}
+
+		/* does a combination of caps satisfy mask? */
+		have |= cap->issued;
+		if ((have & mask) == mask) {
+			dout("__ceph_caps_issued_mask %p combo issued %s"
+			     " (mask %s)\n", &ci->vfs_inode,
+			     ceph_cap_string(cap->issued),
+			     ceph_cap_string(mask));
+			if (touch) {
+				struct rb_node *q;
+
+				/* touch this + preceding caps */
+				__touch_cap(cap);
+				for (q = rb_first(&ci->i_caps); q != p;
+				     q = rb_next(q)) {
+					cap = rb_entry(q, struct ceph_cap,
+						       ci_node);
+					if (!__cap_is_valid(cap))
+						continue;
+					__touch_cap(cap);
+				}
+			}
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Return true if mask caps are currently being revoked by an MDS.
+ */
+int __ceph_caps_revoking_other(struct ceph_inode_info *ci,
+			       struct ceph_cap *ocap, int mask)
+{
+	struct ceph_cap *cap;
+	struct rb_node *p;
+
+	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
+		cap = rb_entry(p, struct ceph_cap, ci_node);
+		if (cap != ocap &&
+		    (cap->implemented & ~cap->issued & mask))
+			return 1;
+	}
+	return 0;
+}
+
+int ceph_caps_revoking(struct ceph_inode_info *ci, int mask)
+{
+	struct inode *inode = &ci->vfs_inode;
+	int ret;
+
+	spin_lock(&ci->i_ceph_lock);
+	ret = __ceph_caps_revoking_other(ci, NULL, mask);
+	spin_unlock(&ci->i_ceph_lock);
+	dout("ceph_caps_revoking %p %s = %d\n", inode,
+	     ceph_cap_string(mask), ret);
+	return ret;
+}
+
+int __ceph_caps_used(struct ceph_inode_info *ci)
+{
+	int used = 0;
+	if (ci->i_pin_ref)
+		used |= CEPH_CAP_PIN;
+	if (ci->i_rd_ref)
+		used |= CEPH_CAP_FILE_RD;
+	if (ci->i_rdcache_ref || ci->vfs_inode.i_data.nrpages)
+		used |= CEPH_CAP_FILE_CACHE;
+	if (ci->i_wr_ref)
+		used |= CEPH_CAP_FILE_WR;
+	if (ci->i_wb_ref || ci->i_wrbuffer_ref)
+		used |= CEPH_CAP_FILE_BUFFER;
+	return used;
+}
+
+/*
+ * wanted, by virtue of open file modes
+ */
+int __ceph_caps_file_wanted(struct ceph_inode_info *ci)
+{
+	int want = 0;
+	int mode;
+	for (mode = 0; mode < CEPH_FILE_MODE_NUM; mode++)
+		if (ci->i_nr_by_mode[mode])
+			want |= ceph_caps_for_mode(mode);
+	return want;
+}
+
+/*
+ * Return caps we have registered with the MDS(s) as 'wanted'.
+ */
+int __ceph_caps_mds_wanted(struct ceph_inode_info *ci)
+{
+	struct ceph_cap *cap;
+	struct rb_node *p;
+	int mds_wanted = 0;
+
+	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
+		cap = rb_entry(p, struct ceph_cap, ci_node);
+		if (!__cap_is_valid(cap))
+			continue;
+		if (cap == ci->i_auth_cap)
+			mds_wanted |= cap->mds_wanted;
+		else
+			mds_wanted |= (cap->mds_wanted & ~CEPH_CAP_ANY_FILE_WR);
+	}
+	return mds_wanted;
+}
+
+/*
+ * called under i_ceph_lock
+ */
+static int __ceph_is_any_caps(struct ceph_inode_info *ci)
+{
+	return !RB_EMPTY_ROOT(&ci->i_caps);
+}
+
+int ceph_is_any_caps(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int ret;
+
+	spin_lock(&ci->i_ceph_lock);
+	ret = __ceph_is_any_caps(ci);
+	spin_unlock(&ci->i_ceph_lock);
+
+	return ret;
+}
+
+static void drop_inode_snap_realm(struct ceph_inode_info *ci)
+{
+	struct ceph_snap_realm *realm = ci->i_snap_realm;
+	spin_lock(&realm->inodes_with_caps_lock);
+	list_del_init(&ci->i_snap_realm_item);
+	ci->i_snap_realm_counter++;
+	ci->i_snap_realm = NULL;
+	spin_unlock(&realm->inodes_with_caps_lock);
+	ceph_put_snap_realm(ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc,
+			    realm);
+}
+
+/*
+ * Remove a cap.  Take steps to deal with a racing iterate_session_caps.
+ *
+ * caller should hold i_ceph_lock.
+ * caller will not hold session s_mutex if called from destroy_inode.
+ */
+void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release)
+{
+	struct ceph_mds_session *session = cap->session;
+	struct ceph_inode_info *ci = cap->ci;
+	struct ceph_mds_client *mdsc =
+		ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
+	int removed = 0;
+
+	dout("__ceph_remove_cap %p from %p\n", cap, &ci->vfs_inode);
+
+	/* remove from session list */
+	spin_lock(&session->s_cap_lock);
+	/*
+	 * s_cap_reconnect is protected by s_cap_lock. no one changes
+	 * s_cap_gen while session is in the reconnect state.
+	 */
+	if (queue_release &&
+	    (!session->s_cap_reconnect ||
+	     cap->cap_gen == session->s_cap_gen))
+		__queue_cap_release(session, ci->i_vino.ino, cap->cap_id,
+				    cap->mseq, cap->issue_seq);
+
+	if (session->s_cap_iterator == cap) {
+		/* not yet, we are iterating over this very cap */
+		dout("__ceph_remove_cap  delaying %p removal from session %p\n",
+		     cap, cap->session);
+	} else {
+		list_del_init(&cap->session_caps);
+		session->s_nr_caps--;
+		cap->session = NULL;
+		removed = 1;
+	}
+	/* protect backpointer with s_cap_lock: see iterate_session_caps */
+	cap->ci = NULL;
+	spin_unlock(&session->s_cap_lock);
+
+	/* remove from inode list */
+	rb_erase(&cap->ci_node, &ci->i_caps);
+	if (ci->i_auth_cap == cap)
+		ci->i_auth_cap = NULL;
+
+	if (removed)
+		ceph_put_cap(mdsc, cap);
+
+	/* when reconnect denied, we remove session caps forcibly,
+	 * i_wr_ref can be non-zero. If there are ongoing write,
+	 * keep i_snap_realm.
+	 */
+	if (!__ceph_is_any_caps(ci) && ci->i_wr_ref == 0 && ci->i_snap_realm)
+		drop_inode_snap_realm(ci);
+
+	if (!__ceph_is_any_real_caps(ci))
+		__cap_delay_cancel(mdsc, ci);
+}
+
+/*
+ * Build and send a cap message to the given MDS.
+ *
+ * Caller should be holding s_mutex.
+ */
+static int send_cap_msg(struct ceph_mds_session *session,
+			u64 ino, u64 cid, int op,
+			int caps, int wanted, int dirty,
+			u32 seq, u64 flush_tid, u32 issue_seq, u32 mseq,
+			u64 size, u64 max_size,
+			struct timespec *mtime, struct timespec *atime,
+			u64 time_warp_seq,
+			kuid_t uid, kgid_t gid, umode_t mode,
+			u64 xattr_version,
+			struct ceph_buffer *xattrs_buf,
+			u64 follows, bool inline_data)
+{
+	struct ceph_mds_caps *fc;
+	struct ceph_msg *msg;
+	void *p;
+	size_t extra_len;
+
+	dout("send_cap_msg %s %llx %llx caps %s wanted %s dirty %s"
+	     " seq %u/%u mseq %u follows %lld size %llu/%llu"
+	     " xattr_ver %llu xattr_len %d\n", ceph_cap_op_name(op),
+	     cid, ino, ceph_cap_string(caps), ceph_cap_string(wanted),
+	     ceph_cap_string(dirty),
+	     seq, issue_seq, mseq, follows, size, max_size,
+	     xattr_version, xattrs_buf ? (int)xattrs_buf->vec.iov_len : 0);
+
+	/* flock buffer size + inline version + inline data size */
+	extra_len = 4 + 8 + 4;
+	msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, sizeof(*fc) + extra_len,
+			   GFP_NOFS, false);
+	if (!msg)
+		return -ENOMEM;
+
+	msg->hdr.tid = cpu_to_le64(flush_tid);
+
+	fc = msg->front.iov_base;
+	memset(fc, 0, sizeof(*fc));
+
+	fc->cap_id = cpu_to_le64(cid);
+	fc->op = cpu_to_le32(op);
+	fc->seq = cpu_to_le32(seq);
+	fc->issue_seq = cpu_to_le32(issue_seq);
+	fc->migrate_seq = cpu_to_le32(mseq);
+	fc->caps = cpu_to_le32(caps);
+	fc->wanted = cpu_to_le32(wanted);
+	fc->dirty = cpu_to_le32(dirty);
+	fc->ino = cpu_to_le64(ino);
+	fc->snap_follows = cpu_to_le64(follows);
+
+	fc->size = cpu_to_le64(size);
+	fc->max_size = cpu_to_le64(max_size);
+	if (mtime)
+		ceph_encode_timespec(&fc->mtime, mtime);
+	if (atime)
+		ceph_encode_timespec(&fc->atime, atime);
+	fc->time_warp_seq = cpu_to_le32(time_warp_seq);
+
+	fc->uid = cpu_to_le32(from_kuid(&init_user_ns, uid));
+	fc->gid = cpu_to_le32(from_kgid(&init_user_ns, gid));
+	fc->mode = cpu_to_le32(mode);
+
+	p = fc + 1;
+	/* flock buffer size */
+	ceph_encode_32(&p, 0);
+	/* inline version */
+	ceph_encode_64(&p, inline_data ? 0 : CEPH_INLINE_NONE);
+	/* inline data size */
+	ceph_encode_32(&p, 0);
+
+	fc->xattr_version = cpu_to_le64(xattr_version);
+	if (xattrs_buf) {
+		msg->middle = ceph_buffer_get(xattrs_buf);
+		fc->xattr_len = cpu_to_le32(xattrs_buf->vec.iov_len);
+		msg->hdr.middle_len = cpu_to_le32(xattrs_buf->vec.iov_len);
+	}
+
+	ceph_con_send(&session->s_con, msg);
+	return 0;
+}
+
+void __queue_cap_release(struct ceph_mds_session *session,
+			 u64 ino, u64 cap_id, u32 migrate_seq,
+			 u32 issue_seq)
+{
+	struct ceph_msg *msg;
+	struct ceph_mds_cap_release *head;
+	struct ceph_mds_cap_item *item;
+
+	BUG_ON(!session->s_num_cap_releases);
+	msg = list_first_entry(&session->s_cap_releases,
+			       struct ceph_msg, list_head);
+
+	dout(" adding %llx release to mds%d msg %p (%d left)\n",
+	     ino, session->s_mds, msg, session->s_num_cap_releases);
+
+	BUG_ON(msg->front.iov_len + sizeof(*item) > PAGE_CACHE_SIZE);
+	head = msg->front.iov_base;
+	le32_add_cpu(&head->num, 1);
+	item = msg->front.iov_base + msg->front.iov_len;
+	item->ino = cpu_to_le64(ino);
+	item->cap_id = cpu_to_le64(cap_id);
+	item->migrate_seq = cpu_to_le32(migrate_seq);
+	item->seq = cpu_to_le32(issue_seq);
+
+	session->s_num_cap_releases--;
+
+	msg->front.iov_len += sizeof(*item);
+	if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
+		dout(" release msg %p full\n", msg);
+		list_move_tail(&msg->list_head, &session->s_cap_releases_done);
+	} else {
+		dout(" release msg %p at %d/%d (%d)\n", msg,
+		     (int)le32_to_cpu(head->num),
+		     (int)CEPH_CAPS_PER_RELEASE,
+		     (int)msg->front.iov_len);
+	}
+}
+
+/*
+ * Queue cap releases when an inode is dropped from our cache.  Since
+ * inode is about to be destroyed, there is no need for i_ceph_lock.
+ */
+void ceph_queue_caps_release(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct rb_node *p;
+
+	p = rb_first(&ci->i_caps);
+	while (p) {
+		struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
+		p = rb_next(p);
+		__ceph_remove_cap(cap, true);
+	}
+}
+
+/*
+ * Send a cap msg on the given inode.  Update our caps state, then
+ * drop i_ceph_lock and send the message.
+ *
+ * Make note of max_size reported/requested from mds, revoked caps
+ * that have now been implemented.
+ *
+ * Make half-hearted attempt ot to invalidate page cache if we are
+ * dropping RDCACHE.  Note that this will leave behind locked pages
+ * that we'll then need to deal with elsewhere.
+ *
+ * Return non-zero if delayed release, or we experienced an error
+ * such that the caller should requeue + retry later.
+ *
+ * called with i_ceph_lock, then drops it.
+ * caller should hold snap_rwsem (read), s_mutex.
+ */
+static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
+		      int op, int used, int want, int retain, int flushing,
+		      unsigned *pflush_tid)
+	__releases(cap->ci->i_ceph_lock)
+{
+	struct ceph_inode_info *ci = cap->ci;
+	struct inode *inode = &ci->vfs_inode;
+	u64 cap_id = cap->cap_id;
+	int held, revoking, dropping, keep;
+	u64 seq, issue_seq, mseq, time_warp_seq, follows;
+	u64 size, max_size;
+	struct timespec mtime, atime;
+	int wake = 0;
+	umode_t mode;
+	kuid_t uid;
+	kgid_t gid;
+	struct ceph_mds_session *session;
+	u64 xattr_version = 0;
+	struct ceph_buffer *xattr_blob = NULL;
+	int delayed = 0;
+	u64 flush_tid = 0;
+	int i;
+	int ret;
+	bool inline_data;
+
+	held = cap->issued | cap->implemented;
+	revoking = cap->implemented & ~cap->issued;
+	retain &= ~revoking;
+	dropping = cap->issued & ~retain;
+
+	dout("__send_cap %p cap %p session %p %s -> %s (revoking %s)\n",
+	     inode, cap, cap->session,
+	     ceph_cap_string(held), ceph_cap_string(held & retain),
+	     ceph_cap_string(revoking));
+	BUG_ON((retain & CEPH_CAP_PIN) == 0);
+
+	session = cap->session;
+
+	/* don't release wanted unless we've waited a bit. */
+	if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0 &&
+	    time_before(jiffies, ci->i_hold_caps_min)) {
+		dout(" delaying issued %s -> %s, wanted %s -> %s on send\n",
+		     ceph_cap_string(cap->issued),
+		     ceph_cap_string(cap->issued & retain),
+		     ceph_cap_string(cap->mds_wanted),
+		     ceph_cap_string(want));
+		want |= cap->mds_wanted;
+		retain |= cap->issued;
+		delayed = 1;
+	}
+	ci->i_ceph_flags &= ~(CEPH_I_NODELAY | CEPH_I_FLUSH);
+
+	cap->issued &= retain;  /* drop bits we don't want */
+	if (cap->implemented & ~cap->issued) {
+		/*
+		 * Wake up any waiters on wanted -> needed transition.
+		 * This is due to the weird transition from buffered
+		 * to sync IO... we need to flush dirty pages _before_
+		 * allowing sync writes to avoid reordering.
+		 */
+		wake = 1;
+	}
+	cap->implemented &= cap->issued | used;
+	cap->mds_wanted = want;
+
+	if (flushing) {
+		/*
+		 * assign a tid for flush operations so we can avoid
+		 * flush1 -> dirty1 -> flush2 -> flushack1 -> mark
+		 * clean type races.  track latest tid for every bit
+		 * so we can handle flush AxFw, flush Fw, and have the
+		 * first ack clean Ax.
+		 */
+		flush_tid = ++ci->i_cap_flush_last_tid;
+		if (pflush_tid)
+			*pflush_tid = flush_tid;
+		dout(" cap_flush_tid %d\n", (int)flush_tid);
+		for (i = 0; i < CEPH_CAP_BITS; i++)
+			if (flushing & (1 << i))
+				ci->i_cap_flush_tid[i] = flush_tid;
+
+		follows = ci->i_head_snapc->seq;
+	} else {
+		follows = 0;
+	}
+
+	keep = cap->implemented;
+	seq = cap->seq;
+	issue_seq = cap->issue_seq;
+	mseq = cap->mseq;
+	size = inode->i_size;
+	ci->i_reported_size = size;
+	max_size = ci->i_wanted_max_size;
+	ci->i_requested_max_size = max_size;
+	mtime = inode->i_mtime;
+	atime = inode->i_atime;
+	time_warp_seq = ci->i_time_warp_seq;
+	uid = inode->i_uid;
+	gid = inode->i_gid;
+	mode = inode->i_mode;
+
+	if (flushing & CEPH_CAP_XATTR_EXCL) {
+		__ceph_build_xattrs_blob(ci);
+		xattr_blob = ci->i_xattrs.blob;
+		xattr_version = ci->i_xattrs.version;
+	}
+
+	inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
+
+	spin_unlock(&ci->i_ceph_lock);
+
+	ret = send_cap_msg(session, ceph_vino(inode).ino, cap_id,
+		op, keep, want, flushing, seq, flush_tid, issue_seq, mseq,
+		size, max_size, &mtime, &atime, time_warp_seq,
+		uid, gid, mode, xattr_version, xattr_blob,
+		follows, inline_data);
+	if (ret < 0) {
+		dout("error sending cap msg, must requeue %p\n", inode);
+		delayed = 1;
+	}
+
+	if (wake)
+		wake_up_all(&ci->i_cap_wq);
+
+	return delayed;
+}
+
+/*
+ * When a snapshot is taken, clients accumulate dirty metadata on
+ * inodes with capabilities in ceph_cap_snaps to describe the file
+ * state at the time the snapshot was taken.  This must be flushed
+ * asynchronously back to the MDS once sync writes complete and dirty
+ * data is written out.
+ *
+ * Unless @again is true, skip cap_snaps that were already sent to
+ * the MDS (i.e., during this session).
+ *
+ * Called under i_ceph_lock.  Takes s_mutex as needed.
+ */
+void __ceph_flush_snaps(struct ceph_inode_info *ci,
+			struct ceph_mds_session **psession,
+			int again)
+		__releases(ci->i_ceph_lock)
+		__acquires(ci->i_ceph_lock)
+{
+	struct inode *inode = &ci->vfs_inode;
+	int mds;
+	struct ceph_cap_snap *capsnap;
+	u32 mseq;
+	struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
+	struct ceph_mds_session *session = NULL; /* if session != NULL, we hold
+						    session->s_mutex */
+	u64 next_follows = 0;  /* keep track of how far we've gotten through the
+			     i_cap_snaps list, and skip these entries next time
+			     around to avoid an infinite loop */
+
+	if (psession)
+		session = *psession;
+
+	dout("__flush_snaps %p\n", inode);
+retry:
+	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
+		/* avoid an infiniute loop after retry */
+		if (capsnap->follows < next_follows)
+			continue;
+		/*
+		 * we need to wait for sync writes to complete and for dirty
+		 * pages to be written out.
+		 */
+		if (capsnap->dirty_pages || capsnap->writing)
+			break;
+
+		/*
+		 * if cap writeback already occurred, we should have dropped
+		 * the capsnap in ceph_put_wrbuffer_cap_refs.
+		 */
+		BUG_ON(capsnap->dirty == 0);
+
+		/* pick mds, take s_mutex */
+		if (ci->i_auth_cap == NULL) {
+			dout("no auth cap (migrating?), doing nothing\n");
+			goto out;
+		}
+
+		/* only flush each capsnap once */
+		if (!again && !list_empty(&capsnap->flushing_item)) {
+			dout("already flushed %p, skipping\n", capsnap);
+			continue;
+		}
+
+		mds = ci->i_auth_cap->session->s_mds;
+		mseq = ci->i_auth_cap->mseq;
+
+		if (session && session->s_mds != mds) {
+			dout("oops, wrong session %p mutex\n", session);
+			mutex_unlock(&session->s_mutex);
+			ceph_put_mds_session(session);
+			session = NULL;
+		}
+		if (!session) {
+			spin_unlock(&ci->i_ceph_lock);
+			mutex_lock(&mdsc->mutex);
+			session = __ceph_lookup_mds_session(mdsc, mds);
+			mutex_unlock(&mdsc->mutex);
+			if (session) {
+				dout("inverting session/ino locks on %p\n",
+				     session);
+				mutex_lock(&session->s_mutex);
+			}
+			/*
+			 * if session == NULL, we raced against a cap
+			 * deletion or migration.  retry, and we'll
+			 * get a better @mds value next time.
+			 */
+			spin_lock(&ci->i_ceph_lock);
+			goto retry;
+		}
+
+		capsnap->flush_tid = ++ci->i_cap_flush_last_tid;
+		atomic_inc(&capsnap->nref);
+		if (!list_empty(&capsnap->flushing_item))
+			list_del_init(&capsnap->flushing_item);
+		list_add_tail(&capsnap->flushing_item,
+			      &session->s_cap_snaps_flushing);
+		spin_unlock(&ci->i_ceph_lock);
+
+		dout("flush_snaps %p cap_snap %p follows %lld tid %llu\n",
+		     inode, capsnap, capsnap->follows, capsnap->flush_tid);
+		send_cap_msg(session, ceph_vino(inode).ino, 0,
+			     CEPH_CAP_OP_FLUSHSNAP, capsnap->issued, 0,
+			     capsnap->dirty, 0, capsnap->flush_tid, 0, mseq,
+			     capsnap->size, 0,
+			     &capsnap->mtime, &capsnap->atime,
+			     capsnap->time_warp_seq,
+			     capsnap->uid, capsnap->gid, capsnap->mode,
+			     capsnap->xattr_version, capsnap->xattr_blob,
+			     capsnap->follows, capsnap->inline_data);
+
+		next_follows = capsnap->follows + 1;
+		ceph_put_cap_snap(capsnap);
+
+		spin_lock(&ci->i_ceph_lock);
+		goto retry;
+	}
+
+	/* we flushed them all; remove this inode from the queue */
+	spin_lock(&mdsc->snap_flush_lock);
+	list_del_init(&ci->i_snap_flush_item);
+	spin_unlock(&mdsc->snap_flush_lock);
+
+out:
+	if (psession)
+		*psession = session;
+	else if (session) {
+		mutex_unlock(&session->s_mutex);
+		ceph_put_mds_session(session);
+	}
+}
+
+static void ceph_flush_snaps(struct ceph_inode_info *ci)
+{
+	spin_lock(&ci->i_ceph_lock);
+	__ceph_flush_snaps(ci, NULL, 0);
+	spin_unlock(&ci->i_ceph_lock);
+}
+
+/*
+ * Mark caps dirty.  If inode is newly dirty, return the dirty flags.
+ * Caller is then responsible for calling __mark_inode_dirty with the
+ * returned flags value.
+ */
+int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask)
+{
+	struct ceph_mds_client *mdsc =
+		ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
+	struct inode *inode = &ci->vfs_inode;
+	int was = ci->i_dirty_caps;
+	int dirty = 0;
+
+	if (!ci->i_auth_cap) {
+		pr_warn("__mark_dirty_caps %p %llx mask %s, "
+			"but no auth cap (session was closed?)\n",
+			inode, ceph_ino(inode), ceph_cap_string(mask));
+		return 0;
+	}
+
+	dout("__mark_dirty_caps %p %s dirty %s -> %s\n", &ci->vfs_inode,
+	     ceph_cap_string(mask), ceph_cap_string(was),
+	     ceph_cap_string(was | mask));
+	ci->i_dirty_caps |= mask;
+	if (was == 0) {
+		if (!ci->i_head_snapc)
+			ci->i_head_snapc = ceph_get_snap_context(
+				ci->i_snap_realm->cached_context);
+		dout(" inode %p now dirty snapc %p auth cap %p\n",
+		     &ci->vfs_inode, ci->i_head_snapc, ci->i_auth_cap);
+		BUG_ON(!list_empty(&ci->i_dirty_item));
+		spin_lock(&mdsc->cap_dirty_lock);
+		list_add(&ci->i_dirty_item, &mdsc->cap_dirty);
+		spin_unlock(&mdsc->cap_dirty_lock);
+		if (ci->i_flushing_caps == 0) {
+			ihold(inode);
+			dirty |= I_DIRTY_SYNC;
+		}
+	}
+	BUG_ON(list_empty(&ci->i_dirty_item));
+	if (((was | ci->i_flushing_caps) & CEPH_CAP_FILE_BUFFER) &&
+	    (mask & CEPH_CAP_FILE_BUFFER))
+		dirty |= I_DIRTY_DATASYNC;
+	__cap_delay_requeue(mdsc, ci);
+	return dirty;
+}
+
+/*
+ * Add dirty inode to the flushing list.  Assigned a seq number so we
+ * can wait for caps to flush without starving.
+ *
+ * Called under i_ceph_lock.
+ */
+static int __mark_caps_flushing(struct inode *inode,
+				 struct ceph_mds_session *session)
+{
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int flushing;
+
+	BUG_ON(ci->i_dirty_caps == 0);
+	BUG_ON(list_empty(&ci->i_dirty_item));
+
+	flushing = ci->i_dirty_caps;
+	dout("__mark_caps_flushing flushing %s, flushing_caps %s -> %s\n",
+	     ceph_cap_string(flushing),
+	     ceph_cap_string(ci->i_flushing_caps),
+	     ceph_cap_string(ci->i_flushing_caps | flushing));
+	ci->i_flushing_caps |= flushing;
+	ci->i_dirty_caps = 0;
+	dout(" inode %p now !dirty\n", inode);
+
+	spin_lock(&mdsc->cap_dirty_lock);
+	list_del_init(&ci->i_dirty_item);
+
+	if (list_empty(&ci->i_flushing_item)) {
+		ci->i_cap_flush_seq = ++mdsc->cap_flush_seq;
+		list_add_tail(&ci->i_flushing_item, &session->s_cap_flushing);
+		mdsc->num_cap_flushing++;
+		dout(" inode %p now flushing seq %lld\n", inode,
+		     ci->i_cap_flush_seq);
+	} else {
+		list_move_tail(&ci->i_flushing_item, &session->s_cap_flushing);
+		dout(" inode %p now flushing (more) seq %lld\n", inode,
+		     ci->i_cap_flush_seq);
+	}
+	spin_unlock(&mdsc->cap_dirty_lock);
+
+	return flushing;
+}
+
+/*
+ * try to invalidate mapping pages without blocking.
+ */
+static int try_nonblocking_invalidate(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	u32 invalidating_gen = ci->i_rdcache_gen;
+
+	spin_unlock(&ci->i_ceph_lock);
+	invalidate_mapping_pages(&inode->i_data, 0, -1);
+	spin_lock(&ci->i_ceph_lock);
+
+	if (inode->i_data.nrpages == 0 &&
+	    invalidating_gen == ci->i_rdcache_gen) {
+		/* success. */
+		dout("try_nonblocking_invalidate %p success\n", inode);
+		/* save any racing async invalidate some trouble */
+		ci->i_rdcache_revoking = ci->i_rdcache_gen - 1;
+		return 0;
+	}
+	dout("try_nonblocking_invalidate %p failed\n", inode);
+	return -1;
+}
+
+/*
+ * Swiss army knife function to examine currently used and wanted
+ * versus held caps.  Release, flush, ack revoked caps to mds as
+ * appropriate.
+ *
+ *  CHECK_CAPS_NODELAY - caller is delayed work and we should not delay
+ *    cap release further.
+ *  CHECK_CAPS_AUTHONLY - we should only check the auth cap
+ *  CHECK_CAPS_FLUSH - we should flush any dirty caps immediately, without
+ *    further delay.
+ */
+void ceph_check_caps(struct ceph_inode_info *ci, int flags,
+		     struct ceph_mds_session *session)
+{
+	struct ceph_fs_client *fsc = ceph_inode_to_client(&ci->vfs_inode);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct inode *inode = &ci->vfs_inode;
+	struct ceph_cap *cap;
+	int file_wanted, used, cap_used;
+	int took_snap_rwsem = 0;             /* true if mdsc->snap_rwsem held */
+	int issued, implemented, want, retain, revoking, flushing = 0;
+	int mds = -1;   /* keep track of how far we've gone through i_caps list
+			   to avoid an infinite loop on retry */
+	struct rb_node *p;
+	int tried_invalidate = 0;
+	int delayed = 0, sent = 0, force_requeue = 0, num;
+	int queue_invalidate = 0;
+	int is_delayed = flags & CHECK_CAPS_NODELAY;
+
+	/* if we are unmounting, flush any unused caps immediately. */
+	if (mdsc->stopping)
+		is_delayed = 1;
+
+	spin_lock(&ci->i_ceph_lock);
+
+	if (ci->i_ceph_flags & CEPH_I_FLUSH)
+		flags |= CHECK_CAPS_FLUSH;
+
+	/* flush snaps first time around only */
+	if (!list_empty(&ci->i_cap_snaps))
+		__ceph_flush_snaps(ci, &session, 0);
+	goto retry_locked;
+retry:
+	spin_lock(&ci->i_ceph_lock);
+retry_locked:
+	file_wanted = __ceph_caps_file_wanted(ci);
+	used = __ceph_caps_used(ci);
+	want = file_wanted | used;
+	issued = __ceph_caps_issued(ci, &implemented);
+	revoking = implemented & ~issued;
+
+	retain = want | CEPH_CAP_PIN;
+	if (!mdsc->stopping && inode->i_nlink > 0) {
+		if (want) {
+			retain |= CEPH_CAP_ANY;       /* be greedy */
+		} else if (S_ISDIR(inode->i_mode) &&
+			   (issued & CEPH_CAP_FILE_SHARED) &&
+			    __ceph_dir_is_complete(ci)) {
+			/*
+			 * If a directory is complete, we want to keep
+			 * the exclusive cap. So that MDS does not end up
+			 * revoking the shared cap on every create/unlink
+			 * operation.
+			 */
+			want = CEPH_CAP_ANY_SHARED | CEPH_CAP_FILE_EXCL;
+			retain |= want;
+		} else {
+
+			retain |= CEPH_CAP_ANY_SHARED;
+			/*
+			 * keep RD only if we didn't have the file open RW,
+			 * because then the mds would revoke it anyway to
+			 * journal max_size=0.
+			 */
+			if (ci->i_max_size == 0)
+				retain |= CEPH_CAP_ANY_RD;
+		}
+	}
+
+	dout("check_caps %p file_want %s used %s dirty %s flushing %s"
+	     " issued %s revoking %s retain %s %s%s%s\n", inode,
+	     ceph_cap_string(file_wanted),
+	     ceph_cap_string(used), ceph_cap_string(ci->i_dirty_caps),
+	     ceph_cap_string(ci->i_flushing_caps),
+	     ceph_cap_string(issued), ceph_cap_string(revoking),
+	     ceph_cap_string(retain),
+	     (flags & CHECK_CAPS_AUTHONLY) ? " AUTHONLY" : "",
+	     (flags & CHECK_CAPS_NODELAY) ? " NODELAY" : "",
+	     (flags & CHECK_CAPS_FLUSH) ? " FLUSH" : "");
+
+	/*
+	 * If we no longer need to hold onto old our caps, and we may
+	 * have cached pages, but don't want them, then try to invalidate.
+	 * If we fail, it's because pages are locked.... try again later.
+	 */
+	if ((!is_delayed || mdsc->stopping) &&
+	    ci->i_wrbuffer_ref == 0 &&               /* no dirty pages... */
+	    inode->i_data.nrpages &&                 /* have cached pages */
+	    (file_wanted == 0 ||                     /* no open files */
+	     (revoking & (CEPH_CAP_FILE_CACHE|
+			  CEPH_CAP_FILE_LAZYIO))) && /*  or revoking cache */
+	    !tried_invalidate) {
+		dout("check_caps trying to invalidate on %p\n", inode);
+		if (try_nonblocking_invalidate(inode) < 0) {
+			if (revoking & (CEPH_CAP_FILE_CACHE|
+					CEPH_CAP_FILE_LAZYIO)) {
+				dout("check_caps queuing invalidate\n");
+				queue_invalidate = 1;
+				ci->i_rdcache_revoking = ci->i_rdcache_gen;
+			} else {
+				dout("check_caps failed to invalidate pages\n");
+				/* we failed to invalidate pages.  check these
+				   caps again later. */
+				force_requeue = 1;
+				__cap_set_timeouts(mdsc, ci);
+			}
+		}
+		tried_invalidate = 1;
+		goto retry_locked;
+	}
+
+	num = 0;
+	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
+		cap = rb_entry(p, struct ceph_cap, ci_node);
+		num++;
+
+		/* avoid looping forever */
+		if (mds >= cap->mds ||
+		    ((flags & CHECK_CAPS_AUTHONLY) && cap != ci->i_auth_cap))
+			continue;
+
+		/* NOTE: no side-effects allowed, until we take s_mutex */
+
+		cap_used = used;
+		if (ci->i_auth_cap && cap != ci->i_auth_cap)
+			cap_used &= ~ci->i_auth_cap->issued;
+
+		revoking = cap->implemented & ~cap->issued;
+		dout(" mds%d cap %p used %s issued %s implemented %s revoking %s\n",
+		     cap->mds, cap, ceph_cap_string(cap->issued),
+		     ceph_cap_string(cap_used),
+		     ceph_cap_string(cap->implemented),
+		     ceph_cap_string(revoking));
+
+		if (cap == ci->i_auth_cap &&
+		    (cap->issued & CEPH_CAP_FILE_WR)) {
+			/* request larger max_size from MDS? */
+			if (ci->i_wanted_max_size > ci->i_max_size &&
+			    ci->i_wanted_max_size > ci->i_requested_max_size) {
+				dout("requesting new max_size\n");
+				goto ack;
+			}
+
+			/* approaching file_max? */
+			if ((inode->i_size << 1) >= ci->i_max_size &&
+			    (ci->i_reported_size << 1) < ci->i_max_size) {
+				dout("i_size approaching max_size\n");
+				goto ack;
+			}
+		}
+		/* flush anything dirty? */
+		if (cap == ci->i_auth_cap && (flags & CHECK_CAPS_FLUSH) &&
+		    ci->i_dirty_caps) {
+			dout("flushing dirty caps\n");
+			goto ack;
+		}
+
+		/* completed revocation? going down and there are no caps? */
+		if (revoking && (revoking & cap_used) == 0) {
+			dout("completed revocation of %s\n",
+			     ceph_cap_string(cap->implemented & ~cap->issued));
+			goto ack;
+		}
+
+		/* want more caps from mds? */
+		if (want & ~(cap->mds_wanted | cap->issued))
+			goto ack;
+
+		/* things we might delay */
+		if ((cap->issued & ~retain) == 0 &&
+		    cap->mds_wanted == want)
+			continue;     /* nope, all good */
+
+		if (is_delayed)
+			goto ack;
+
+		/* delay? */
+		if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0 &&
+		    time_before(jiffies, ci->i_hold_caps_max)) {
+			dout(" delaying issued %s -> %s, wanted %s -> %s\n",
+			     ceph_cap_string(cap->issued),
+			     ceph_cap_string(cap->issued & retain),
+			     ceph_cap_string(cap->mds_wanted),
+			     ceph_cap_string(want));
+			delayed++;
+			continue;
+		}
+
+ack:
+		if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
+			dout(" skipping %p I_NOFLUSH set\n", inode);
+			continue;
+		}
+
+		if (session && session != cap->session) {
+			dout("oops, wrong session %p mutex\n", session);
+			mutex_unlock(&session->s_mutex);
+			session = NULL;
+		}
+		if (!session) {
+			session = cap->session;
+			if (mutex_trylock(&session->s_mutex) == 0) {
+				dout("inverting session/ino locks on %p\n",
+				     session);
+				spin_unlock(&ci->i_ceph_lock);
+				if (took_snap_rwsem) {
+					up_read(&mdsc->snap_rwsem);
+					took_snap_rwsem = 0;
+				}
+				mutex_lock(&session->s_mutex);
+				goto retry;
+			}
+		}
+		/* take snap_rwsem after session mutex */
+		if (!took_snap_rwsem) {
+			if (down_read_trylock(&mdsc->snap_rwsem) == 0) {
+				dout("inverting snap/in locks on %p\n",
+				     inode);
+				spin_unlock(&ci->i_ceph_lock);
+				down_read(&mdsc->snap_rwsem);
+				took_snap_rwsem = 1;
+				goto retry;
+			}
+			took_snap_rwsem = 1;
+		}
+
+		if (cap == ci->i_auth_cap && ci->i_dirty_caps)
+			flushing = __mark_caps_flushing(inode, session);
+		else
+			flushing = 0;
+
+		mds = cap->mds;  /* remember mds, so we don't repeat */
+		sent++;
+
+		/* __send_cap drops i_ceph_lock */
+		delayed += __send_cap(mdsc, cap, CEPH_CAP_OP_UPDATE, cap_used,
+				      want, retain, flushing, NULL);
+		goto retry; /* retake i_ceph_lock and restart our cap scan. */
+	}
+
+	/*
+	 * Reschedule delayed caps release if we delayed anything,
+	 * otherwise cancel.
+	 */
+	if (delayed && is_delayed)
+		force_requeue = 1;   /* __send_cap delayed release; requeue */
+	if (!delayed && !is_delayed)
+		__cap_delay_cancel(mdsc, ci);
+	else if (!is_delayed || force_requeue)
+		__cap_delay_requeue(mdsc, ci);
+
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (queue_invalidate)
+		ceph_queue_invalidate(inode);
+
+	if (session)
+		mutex_unlock(&session->s_mutex);
+	if (took_snap_rwsem)
+		up_read(&mdsc->snap_rwsem);
+}
+
+/*
+ * Try to flush dirty caps back to the auth mds.
+ */
+static int try_flush_caps(struct inode *inode, unsigned *flush_tid)
+{
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int flushing = 0;
+	struct ceph_mds_session *session = NULL;
+
+retry:
+	spin_lock(&ci->i_ceph_lock);
+	if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
+		dout("try_flush_caps skipping %p I_NOFLUSH set\n", inode);
+		goto out;
+	}
+	if (ci->i_dirty_caps && ci->i_auth_cap) {
+		struct ceph_cap *cap = ci->i_auth_cap;
+		int used = __ceph_caps_used(ci);
+		int want = __ceph_caps_wanted(ci);
+		int delayed;
+
+		if (!session || session != cap->session) {
+			spin_unlock(&ci->i_ceph_lock);
+			if (session)
+				mutex_unlock(&session->s_mutex);
+			session = cap->session;
+			mutex_lock(&session->s_mutex);
+			goto retry;
+		}
+		if (cap->session->s_state < CEPH_MDS_SESSION_OPEN)
+			goto out;
+
+		flushing = __mark_caps_flushing(inode, session);
+
+		/* __send_cap drops i_ceph_lock */
+		delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH, used, want,
+				     cap->issued | cap->implemented, flushing,
+				     flush_tid);
+		if (!delayed)
+			goto out_unlocked;
+
+		spin_lock(&ci->i_ceph_lock);
+		__cap_delay_requeue(mdsc, ci);
+	}
+out:
+	spin_unlock(&ci->i_ceph_lock);
+out_unlocked:
+	if (session)
+		mutex_unlock(&session->s_mutex);
+	return flushing;
+}
+
+/*
+ * Return true if we've flushed caps through the given flush_tid.
+ */
+static int caps_are_flushed(struct inode *inode, unsigned tid)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int i, ret = 1;
+
+	spin_lock(&ci->i_ceph_lock);
+	for (i = 0; i < CEPH_CAP_BITS; i++)
+		if ((ci->i_flushing_caps & (1 << i)) &&
+		    ci->i_cap_flush_tid[i] <= tid) {
+			/* still flushing this bit */
+			ret = 0;
+			break;
+		}
+	spin_unlock(&ci->i_ceph_lock);
+	return ret;
+}
+
+/*
+ * Wait on any unsafe replies for the given inode.  First wait on the
+ * newest request, and make that the upper bound.  Then, if there are
+ * more requests, keep waiting on the oldest as long as it is still older
+ * than the original request.
+ */
+static void sync_write_wait(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct list_head *head = &ci->i_unsafe_writes;
+	struct ceph_osd_request *req;
+	u64 last_tid;
+
+	spin_lock(&ci->i_unsafe_lock);
+	if (list_empty(head))
+		goto out;
+
+	/* set upper bound as _last_ entry in chain */
+	req = list_entry(head->prev, struct ceph_osd_request,
+			 r_unsafe_item);
+	last_tid = req->r_tid;
+
+	do {
+		ceph_osdc_get_request(req);
+		spin_unlock(&ci->i_unsafe_lock);
+		dout("sync_write_wait on tid %llu (until %llu)\n",
+		     req->r_tid, last_tid);
+		wait_for_completion(&req->r_safe_completion);
+		spin_lock(&ci->i_unsafe_lock);
+		ceph_osdc_put_request(req);
+
+		/*
+		 * from here on look at first entry in chain, since we
+		 * only want to wait for anything older than last_tid
+		 */
+		if (list_empty(head))
+			break;
+		req = list_entry(head->next, struct ceph_osd_request,
+				 r_unsafe_item);
+	} while (req->r_tid < last_tid);
+out:
+	spin_unlock(&ci->i_unsafe_lock);
+}
+
+int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	unsigned flush_tid;
+	int ret;
+	int dirty;
+
+	dout("fsync %p%s\n", inode, datasync ? " datasync" : "");
+	sync_write_wait(inode);
+
+	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (ret < 0)
+		return ret;
+	mutex_lock(&inode->i_mutex);
+
+	dirty = try_flush_caps(inode, &flush_tid);
+	dout("fsync dirty caps are %s\n", ceph_cap_string(dirty));
+
+	/*
+	 * only wait on non-file metadata writeback (the mds
+	 * can recover size and mtime, so we don't need to
+	 * wait for that)
+	 */
+	if (!datasync && (dirty & ~CEPH_CAP_ANY_FILE_WR)) {
+		dout("fsync waiting for flush_tid %u\n", flush_tid);
+		ret = wait_event_interruptible(ci->i_cap_wq,
+				       caps_are_flushed(inode, flush_tid));
+	}
+
+	dout("fsync %p%s done\n", inode, datasync ? " datasync" : "");
+	mutex_unlock(&inode->i_mutex);
+	return ret;
+}
+
+/*
+ * Flush any dirty caps back to the mds.  If we aren't asked to wait,
+ * queue inode for flush but don't do so immediately, because we can
+ * get by with fewer MDS messages if we wait for data writeback to
+ * complete first.
+ */
+int ceph_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	unsigned flush_tid;
+	int err = 0;
+	int dirty;
+	int wait = wbc->sync_mode == WB_SYNC_ALL;
+
+	dout("write_inode %p wait=%d\n", inode, wait);
+	if (wait) {
+		dirty = try_flush_caps(inode, &flush_tid);
+		if (dirty)
+			err = wait_event_interruptible(ci->i_cap_wq,
+				       caps_are_flushed(inode, flush_tid));
+	} else {
+		struct ceph_mds_client *mdsc =
+			ceph_sb_to_client(inode->i_sb)->mdsc;
+
+		spin_lock(&ci->i_ceph_lock);
+		if (__ceph_caps_dirty(ci))
+			__cap_delay_requeue_front(mdsc, ci);
+		spin_unlock(&ci->i_ceph_lock);
+	}
+	return err;
+}
+
+/*
+ * After a recovering MDS goes active, we need to resend any caps
+ * we were flushing.
+ *
+ * Caller holds session->s_mutex.
+ */
+static void kick_flushing_capsnaps(struct ceph_mds_client *mdsc,
+				   struct ceph_mds_session *session)
+{
+	struct ceph_cap_snap *capsnap;
+
+	dout("kick_flushing_capsnaps mds%d\n", session->s_mds);
+	list_for_each_entry(capsnap, &session->s_cap_snaps_flushing,
+			    flushing_item) {
+		struct ceph_inode_info *ci = capsnap->ci;
+		struct inode *inode = &ci->vfs_inode;
+		struct ceph_cap *cap;
+
+		spin_lock(&ci->i_ceph_lock);
+		cap = ci->i_auth_cap;
+		if (cap && cap->session == session) {
+			dout("kick_flushing_caps %p cap %p capsnap %p\n", inode,
+			     cap, capsnap);
+			__ceph_flush_snaps(ci, &session, 1);
+		} else {
+			pr_err("%p auth cap %p not mds%d ???\n", inode,
+			       cap, session->s_mds);
+		}
+		spin_unlock(&ci->i_ceph_lock);
+	}
+}
+
+void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
+			     struct ceph_mds_session *session)
+{
+	struct ceph_inode_info *ci;
+
+	kick_flushing_capsnaps(mdsc, session);
+
+	dout("kick_flushing_caps mds%d\n", session->s_mds);
+	list_for_each_entry(ci, &session->s_cap_flushing, i_flushing_item) {
+		struct inode *inode = &ci->vfs_inode;
+		struct ceph_cap *cap;
+		int delayed = 0;
+
+		spin_lock(&ci->i_ceph_lock);
+		cap = ci->i_auth_cap;
+		if (cap && cap->session == session) {
+			dout("kick_flushing_caps %p cap %p %s\n", inode,
+			     cap, ceph_cap_string(ci->i_flushing_caps));
+			delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
+					     __ceph_caps_used(ci),
+					     __ceph_caps_wanted(ci),
+					     cap->issued | cap->implemented,
+					     ci->i_flushing_caps, NULL);
+			if (delayed) {
+				spin_lock(&ci->i_ceph_lock);
+				__cap_delay_requeue(mdsc, ci);
+				spin_unlock(&ci->i_ceph_lock);
+			}
+		} else {
+			pr_err("%p auth cap %p not mds%d ???\n", inode,
+			       cap, session->s_mds);
+			spin_unlock(&ci->i_ceph_lock);
+		}
+	}
+}
+
+static void kick_flushing_inode_caps(struct ceph_mds_client *mdsc,
+				     struct ceph_mds_session *session,
+				     struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_cap *cap;
+	int delayed = 0;
+
+	spin_lock(&ci->i_ceph_lock);
+	cap = ci->i_auth_cap;
+	dout("kick_flushing_inode_caps %p flushing %s flush_seq %lld\n", inode,
+	     ceph_cap_string(ci->i_flushing_caps), ci->i_cap_flush_seq);
+
+	__ceph_flush_snaps(ci, &session, 1);
+
+	if (ci->i_flushing_caps) {
+		spin_lock(&mdsc->cap_dirty_lock);
+		list_move_tail(&ci->i_flushing_item,
+			       &cap->session->s_cap_flushing);
+		spin_unlock(&mdsc->cap_dirty_lock);
+
+		delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
+				     __ceph_caps_used(ci),
+				     __ceph_caps_wanted(ci),
+				     cap->issued | cap->implemented,
+				     ci->i_flushing_caps, NULL);
+		if (delayed) {
+			spin_lock(&ci->i_ceph_lock);
+			__cap_delay_requeue(mdsc, ci);
+			spin_unlock(&ci->i_ceph_lock);
+		}
+	} else {
+		spin_unlock(&ci->i_ceph_lock);
+	}
+}
+
+
+/*
+ * Take references to capabilities we hold, so that we don't release
+ * them to the MDS prematurely.
+ *
+ * Protected by i_ceph_lock.
+ */
+static void __take_cap_refs(struct ceph_inode_info *ci, int got)
+{
+	if (got & CEPH_CAP_PIN)
+		ci->i_pin_ref++;
+	if (got & CEPH_CAP_FILE_RD)
+		ci->i_rd_ref++;
+	if (got & CEPH_CAP_FILE_CACHE)
+		ci->i_rdcache_ref++;
+	if (got & CEPH_CAP_FILE_WR)
+		ci->i_wr_ref++;
+	if (got & CEPH_CAP_FILE_BUFFER) {
+		if (ci->i_wb_ref == 0)
+			ihold(&ci->vfs_inode);
+		ci->i_wb_ref++;
+		dout("__take_cap_refs %p wb %d -> %d (?)\n",
+		     &ci->vfs_inode, ci->i_wb_ref-1, ci->i_wb_ref);
+	}
+}
+
+/*
+ * Try to grab cap references.  Specify those refs we @want, and the
+ * minimal set we @need.  Also include the larger offset we are writing
+ * to (when applicable), and check against max_size here as well.
+ * Note that caller is responsible for ensuring max_size increases are
+ * requested from the MDS.
+ */
+static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
+			    loff_t endoff, int *got, int *check_max, int *err)
+{
+	struct inode *inode = &ci->vfs_inode;
+	int ret = 0;
+	int have, implemented;
+	int file_wanted;
+
+	dout("get_cap_refs %p need %s want %s\n", inode,
+	     ceph_cap_string(need), ceph_cap_string(want));
+
+	spin_lock(&ci->i_ceph_lock);
+
+	/* make sure file is actually open */
+	file_wanted = __ceph_caps_file_wanted(ci);
+	if ((file_wanted & need) == 0) {
+		dout("try_get_cap_refs need %s file_wanted %s, EBADF\n",
+		     ceph_cap_string(need), ceph_cap_string(file_wanted));
+		*err = -EBADF;
+		ret = 1;
+		goto out_unlock;
+	}
+
+	/* finish pending truncate */
+	while (ci->i_truncate_pending) {
+		spin_unlock(&ci->i_ceph_lock);
+		__ceph_do_pending_vmtruncate(inode);
+		spin_lock(&ci->i_ceph_lock);
+	}
+
+	have = __ceph_caps_issued(ci, &implemented);
+
+	if (have & need & CEPH_CAP_FILE_WR) {
+		if (endoff >= 0 && endoff > (loff_t)ci->i_max_size) {
+			dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
+			     inode, endoff, ci->i_max_size);
+			if (endoff > ci->i_requested_max_size) {
+				*check_max = 1;
+				ret = 1;
+			}
+			goto out_unlock;
+		}
+		/*
+		 * If a sync write is in progress, we must wait, so that we
+		 * can get a final snapshot value for size+mtime.
+		 */
+		if (__ceph_have_pending_cap_snap(ci)) {
+			dout("get_cap_refs %p cap_snap_pending\n", inode);
+			goto out_unlock;
+		}
+	}
+
+	if ((have & need) == need) {
+		/*
+		 * Look at (implemented & ~have & not) so that we keep waiting
+		 * on transition from wanted -> needed caps.  This is needed
+		 * for WRBUFFER|WR -> WR to avoid a new WR sync write from
+		 * going before a prior buffered writeback happens.
+		 */
+		int not = want & ~(have & need);
+		int revoking = implemented & ~have;
+		dout("get_cap_refs %p have %s but not %s (revoking %s)\n",
+		     inode, ceph_cap_string(have), ceph_cap_string(not),
+		     ceph_cap_string(revoking));
+		if ((revoking & not) == 0) {
+			*got = need | (have & want);
+			__take_cap_refs(ci, *got);
+			ret = 1;
+		}
+	} else {
+		int session_readonly = false;
+		if ((need & CEPH_CAP_FILE_WR) && ci->i_auth_cap) {
+			struct ceph_mds_session *s = ci->i_auth_cap->session;
+			spin_lock(&s->s_cap_lock);
+			session_readonly = s->s_readonly;
+			spin_unlock(&s->s_cap_lock);
+		}
+		if (session_readonly) {
+			dout("get_cap_refs %p needed %s but mds%d readonly\n",
+			     inode, ceph_cap_string(need), ci->i_auth_cap->mds);
+			*err = -EROFS;
+			ret = 1;
+			goto out_unlock;
+		}
+
+		dout("get_cap_refs %p have %s needed %s\n", inode,
+		     ceph_cap_string(have), ceph_cap_string(need));
+	}
+out_unlock:
+	spin_unlock(&ci->i_ceph_lock);
+
+	dout("get_cap_refs %p ret %d got %s\n", inode,
+	     ret, ceph_cap_string(*got));
+	return ret;
+}
+
+/*
+ * Check the offset we are writing up to against our current
+ * max_size.  If necessary, tell the MDS we want to write to
+ * a larger offset.
+ */
+static void check_max_size(struct inode *inode, loff_t endoff)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int check = 0;
+
+	/* do we need to explicitly request a larger max_size? */
+	spin_lock(&ci->i_ceph_lock);
+	if (endoff >= ci->i_max_size && endoff > ci->i_wanted_max_size) {
+		dout("write %p at large endoff %llu, req max_size\n",
+		     inode, endoff);
+		ci->i_wanted_max_size = endoff;
+	}
+	/* duplicate ceph_check_caps()'s logic */
+	if (ci->i_auth_cap &&
+	    (ci->i_auth_cap->issued & CEPH_CAP_FILE_WR) &&
+	    ci->i_wanted_max_size > ci->i_max_size &&
+	    ci->i_wanted_max_size > ci->i_requested_max_size)
+		check = 1;
+	spin_unlock(&ci->i_ceph_lock);
+	if (check)
+		ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
+}
+
+/*
+ * Wait for caps, and take cap references.  If we can't get a WR cap
+ * due to a small max_size, make sure we check_max_size (and possibly
+ * ask the mds) so we don't get hung up indefinitely.
+ */
+int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
+		  loff_t endoff, int *got, struct page **pinned_page)
+{
+	int _got, check_max, ret, err = 0;
+
+retry:
+	if (endoff > 0)
+		check_max_size(&ci->vfs_inode, endoff);
+	_got = 0;
+	check_max = 0;
+	ret = wait_event_interruptible(ci->i_cap_wq,
+				try_get_cap_refs(ci, need, want, endoff,
+						 &_got, &check_max, &err));
+	if (err)
+		ret = err;
+	if (ret < 0)
+		return ret;
+
+	if (check_max)
+		goto retry;
+
+	if (ci->i_inline_version != CEPH_INLINE_NONE &&
+	    (_got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
+	    i_size_read(&ci->vfs_inode) > 0) {
+		struct page *page = find_get_page(ci->vfs_inode.i_mapping, 0);
+		if (page) {
+			if (PageUptodate(page)) {
+				*pinned_page = page;
+				goto out;
+			}
+			page_cache_release(page);
+		}
+		/*
+		 * drop cap refs first because getattr while holding
+		 * caps refs can cause deadlock.
+		 */
+		ceph_put_cap_refs(ci, _got);
+		_got = 0;
+
+		/* getattr request will bring inline data into page cache */
+		ret = __ceph_do_getattr(&ci->vfs_inode, NULL,
+					CEPH_STAT_CAP_INLINE_DATA, true);
+		if (ret < 0)
+			return ret;
+		goto retry;
+	}
+out:
+	*got = _got;
+	return 0;
+}
+
+/*
+ * Take cap refs.  Caller must already know we hold at least one ref
+ * on the caps in question or we don't know this is safe.
+ */
+void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps)
+{
+	spin_lock(&ci->i_ceph_lock);
+	__take_cap_refs(ci, caps);
+	spin_unlock(&ci->i_ceph_lock);
+}
+
+/*
+ * Release cap refs.
+ *
+ * If we released the last ref on any given cap, call ceph_check_caps
+ * to release (or schedule a release).
+ *
+ * If we are releasing a WR cap (from a sync write), finalize any affected
+ * cap_snap, and wake up any waiters.
+ */
+void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
+{
+	struct inode *inode = &ci->vfs_inode;
+	int last = 0, put = 0, flushsnaps = 0, wake = 0;
+	struct ceph_cap_snap *capsnap;
+
+	spin_lock(&ci->i_ceph_lock);
+	if (had & CEPH_CAP_PIN)
+		--ci->i_pin_ref;
+	if (had & CEPH_CAP_FILE_RD)
+		if (--ci->i_rd_ref == 0)
+			last++;
+	if (had & CEPH_CAP_FILE_CACHE)
+		if (--ci->i_rdcache_ref == 0)
+			last++;
+	if (had & CEPH_CAP_FILE_BUFFER) {
+		if (--ci->i_wb_ref == 0) {
+			last++;
+			put++;
+		}
+		dout("put_cap_refs %p wb %d -> %d (?)\n",
+		     inode, ci->i_wb_ref+1, ci->i_wb_ref);
+	}
+	if (had & CEPH_CAP_FILE_WR)
+		if (--ci->i_wr_ref == 0) {
+			last++;
+			if (!list_empty(&ci->i_cap_snaps)) {
+				capsnap = list_first_entry(&ci->i_cap_snaps,
+						     struct ceph_cap_snap,
+						     ci_item);
+				if (capsnap->writing) {
+					capsnap->writing = 0;
+					flushsnaps =
+						__ceph_finish_cap_snap(ci,
+								       capsnap);
+					wake = 1;
+				}
+			}
+			/* see comment in __ceph_remove_cap() */
+			if (!__ceph_is_any_caps(ci) && ci->i_snap_realm)
+				drop_inode_snap_realm(ci);
+		}
+	spin_unlock(&ci->i_ceph_lock);
+
+	dout("put_cap_refs %p had %s%s%s\n", inode, ceph_cap_string(had),
+	     last ? " last" : "", put ? " put" : "");
+
+	if (last && !flushsnaps)
+		ceph_check_caps(ci, 0, NULL);
+	else if (flushsnaps)
+		ceph_flush_snaps(ci);
+	if (wake)
+		wake_up_all(&ci->i_cap_wq);
+	if (put)
+		iput(inode);
+}
+
+/*
+ * Release @nr WRBUFFER refs on dirty pages for the given @snapc snap
+ * context.  Adjust per-snap dirty page accounting as appropriate.
+ * Once all dirty data for a cap_snap is flushed, flush snapped file
+ * metadata back to the MDS.  If we dropped the last ref, call
+ * ceph_check_caps.
+ */
+void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
+				struct ceph_snap_context *snapc)
+{
+	struct inode *inode = &ci->vfs_inode;
+	int last = 0;
+	int complete_capsnap = 0;
+	int drop_capsnap = 0;
+	int found = 0;
+	struct ceph_cap_snap *capsnap = NULL;
+
+	spin_lock(&ci->i_ceph_lock);
+	ci->i_wrbuffer_ref -= nr;
+	last = !ci->i_wrbuffer_ref;
+
+	if (ci->i_head_snapc == snapc) {
+		ci->i_wrbuffer_ref_head -= nr;
+		if (ci->i_wrbuffer_ref_head == 0 &&
+		    ci->i_dirty_caps == 0 && ci->i_flushing_caps == 0) {
+			BUG_ON(!ci->i_head_snapc);
+			ceph_put_snap_context(ci->i_head_snapc);
+			ci->i_head_snapc = NULL;
+		}
+		dout("put_wrbuffer_cap_refs on %p head %d/%d -> %d/%d %s\n",
+		     inode,
+		     ci->i_wrbuffer_ref+nr, ci->i_wrbuffer_ref_head+nr,
+		     ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
+		     last ? " LAST" : "");
+	} else {
+		list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
+			if (capsnap->context == snapc) {
+				found = 1;
+				break;
+			}
+		}
+		BUG_ON(!found);
+		capsnap->dirty_pages -= nr;
+		if (capsnap->dirty_pages == 0) {
+			complete_capsnap = 1;
+			if (capsnap->dirty == 0)
+				/* cap writeback completed before we created
+				 * the cap_snap; no FLUSHSNAP is needed */
+				drop_capsnap = 1;
+		}
+		dout("put_wrbuffer_cap_refs on %p cap_snap %p "
+		     " snap %lld %d/%d -> %d/%d %s%s%s\n",
+		     inode, capsnap, capsnap->context->seq,
+		     ci->i_wrbuffer_ref+nr, capsnap->dirty_pages + nr,
+		     ci->i_wrbuffer_ref, capsnap->dirty_pages,
+		     last ? " (wrbuffer last)" : "",
+		     complete_capsnap ? " (complete capsnap)" : "",
+		     drop_capsnap ? " (drop capsnap)" : "");
+		if (drop_capsnap) {
+			ceph_put_snap_context(capsnap->context);
+			list_del(&capsnap->ci_item);
+			list_del(&capsnap->flushing_item);
+			ceph_put_cap_snap(capsnap);
+		}
+	}
+
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (last) {
+		ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
+		iput(inode);
+	} else if (complete_capsnap) {
+		ceph_flush_snaps(ci);
+		wake_up_all(&ci->i_cap_wq);
+	}
+	if (drop_capsnap)
+		iput(inode);
+}
+
+/*
+ * Invalidate unlinked inode's aliases, so we can drop the inode ASAP.
+ */
+static void invalidate_aliases(struct inode *inode)
+{
+	struct dentry *dn, *prev = NULL;
+
+	dout("invalidate_aliases inode %p\n", inode);
+	d_prune_aliases(inode);
+	/*
+	 * For non-directory inode, d_find_alias() only returns
+	 * hashed dentry. After calling d_invalidate(), the
+	 * dentry becomes unhashed.
+	 *
+	 * For directory inode, d_find_alias() can return
+	 * unhashed dentry. But directory inode should have
+	 * one alias at most.
+	 */
+	while ((dn = d_find_alias(inode))) {
+		if (dn == prev) {
+			dput(dn);
+			break;
+		}
+		d_invalidate(dn);
+		if (prev)
+			dput(prev);
+		prev = dn;
+	}
+	if (prev)
+		dput(prev);
+}
+
+/*
+ * Handle a cap GRANT message from the MDS.  (Note that a GRANT may
+ * actually be a revocation if it specifies a smaller cap set.)
+ *
+ * caller holds s_mutex and i_ceph_lock, we drop both.
+ */
+static void handle_cap_grant(struct ceph_mds_client *mdsc,
+			     struct inode *inode, struct ceph_mds_caps *grant,
+			     u64 inline_version,
+			     void *inline_data, int inline_len,
+			     struct ceph_buffer *xattr_buf,
+			     struct ceph_mds_session *session,
+			     struct ceph_cap *cap, int issued)
+	__releases(ci->i_ceph_lock)
+	__releases(mdsc->snap_rwsem)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int mds = session->s_mds;
+	int seq = le32_to_cpu(grant->seq);
+	int newcaps = le32_to_cpu(grant->caps);
+	int used, wanted, dirty;
+	u64 size = le64_to_cpu(grant->size);
+	u64 max_size = le64_to_cpu(grant->max_size);
+	struct timespec mtime, atime, ctime;
+	int check_caps = 0;
+	bool wake = false;
+	bool writeback = false;
+	bool queue_trunc = false;
+	bool queue_invalidate = false;
+	bool queue_revalidate = false;
+	bool deleted_inode = false;
+	bool fill_inline = false;
+
+	dout("handle_cap_grant inode %p cap %p mds%d seq %d %s\n",
+	     inode, cap, mds, seq, ceph_cap_string(newcaps));
+	dout(" size %llu max_size %llu, i_size %llu\n", size, max_size,
+		inode->i_size);
+
+
+	/*
+	 * auth mds of the inode changed. we received the cap export message,
+	 * but still haven't received the cap import message. handle_cap_export
+	 * updated the new auth MDS' cap.
+	 *
+	 * "ceph_seq_cmp(seq, cap->seq) <= 0" means we are processing a message
+	 * that was sent before the cap import message. So don't remove caps.
+	 */
+	if (ceph_seq_cmp(seq, cap->seq) <= 0) {
+		WARN_ON(cap != ci->i_auth_cap);
+		WARN_ON(cap->cap_id != le64_to_cpu(grant->cap_id));
+		seq = cap->seq;
+		newcaps |= cap->issued;
+	}
+
+	/*
+	 * If CACHE is being revoked, and we have no dirty buffers,
+	 * try to invalidate (once).  (If there are dirty buffers, we
+	 * will invalidate _after_ writeback.)
+	 */
+	if (((cap->issued & ~newcaps) & CEPH_CAP_FILE_CACHE) &&
+	    (newcaps & CEPH_CAP_FILE_LAZYIO) == 0 &&
+	    !ci->i_wrbuffer_ref) {
+		if (try_nonblocking_invalidate(inode)) {
+			/* there were locked pages.. invalidate later
+			   in a separate thread. */
+			if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
+				queue_invalidate = true;
+				ci->i_rdcache_revoking = ci->i_rdcache_gen;
+			}
+		}
+
+		ceph_fscache_invalidate(inode);
+	}
+
+	/* side effects now are allowed */
+	cap->cap_gen = session->s_cap_gen;
+	cap->seq = seq;
+
+	__check_cap_issue(ci, cap, newcaps);
+
+	if ((newcaps & CEPH_CAP_AUTH_SHARED) &&
+	    (issued & CEPH_CAP_AUTH_EXCL) == 0) {
+		inode->i_mode = le32_to_cpu(grant->mode);
+		inode->i_uid = make_kuid(&init_user_ns, le32_to_cpu(grant->uid));
+		inode->i_gid = make_kgid(&init_user_ns, le32_to_cpu(grant->gid));
+		dout("%p mode 0%o uid.gid %d.%d\n", inode, inode->i_mode,
+		     from_kuid(&init_user_ns, inode->i_uid),
+		     from_kgid(&init_user_ns, inode->i_gid));
+	}
+
+	if ((newcaps & CEPH_CAP_AUTH_SHARED) &&
+	    (issued & CEPH_CAP_LINK_EXCL) == 0) {
+		set_nlink(inode, le32_to_cpu(grant->nlink));
+		if (inode->i_nlink == 0 &&
+		    (newcaps & (CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL)))
+			deleted_inode = true;
+	}
+
+	if ((issued & CEPH_CAP_XATTR_EXCL) == 0 && grant->xattr_len) {
+		int len = le32_to_cpu(grant->xattr_len);
+		u64 version = le64_to_cpu(grant->xattr_version);
+
+		if (version > ci->i_xattrs.version) {
+			dout(" got new xattrs v%llu on %p len %d\n",
+			     version, inode, len);
+			if (ci->i_xattrs.blob)
+				ceph_buffer_put(ci->i_xattrs.blob);
+			ci->i_xattrs.blob = ceph_buffer_get(xattr_buf);
+			ci->i_xattrs.version = version;
+			ceph_forget_all_cached_acls(inode);
+		}
+	}
+
+	/* Do we need to revalidate our fscache cookie. Don't bother on the
+	 * first cache cap as we already validate at cookie creation time. */
+	if ((issued & CEPH_CAP_FILE_CACHE) && ci->i_rdcache_gen > 1)
+		queue_revalidate = true;
+
+	if (newcaps & CEPH_CAP_ANY_RD) {
+		/* ctime/mtime/atime? */
+		ceph_decode_timespec(&mtime, &grant->mtime);
+		ceph_decode_timespec(&atime, &grant->atime);
+		ceph_decode_timespec(&ctime, &grant->ctime);
+		ceph_fill_file_time(inode, issued,
+				    le32_to_cpu(grant->time_warp_seq),
+				    &ctime, &mtime, &atime);
+	}
+
+	if (newcaps & (CEPH_CAP_ANY_FILE_RD | CEPH_CAP_ANY_FILE_WR)) {
+		/* file layout may have changed */
+		ci->i_layout = grant->layout;
+		/* size/truncate_seq? */
+		queue_trunc = ceph_fill_file_size(inode, issued,
+					le32_to_cpu(grant->truncate_seq),
+					le64_to_cpu(grant->truncate_size),
+					size);
+		/* max size increase? */
+		if (ci->i_auth_cap == cap && max_size != ci->i_max_size) {
+			dout("max_size %lld -> %llu\n",
+			     ci->i_max_size, max_size);
+			ci->i_max_size = max_size;
+			if (max_size >= ci->i_wanted_max_size) {
+				ci->i_wanted_max_size = 0;  /* reset */
+				ci->i_requested_max_size = 0;
+			}
+			wake = true;
+		}
+	}
+
+	/* check cap bits */
+	wanted = __ceph_caps_wanted(ci);
+	used = __ceph_caps_used(ci);
+	dirty = __ceph_caps_dirty(ci);
+	dout(" my wanted = %s, used = %s, dirty %s\n",
+	     ceph_cap_string(wanted),
+	     ceph_cap_string(used),
+	     ceph_cap_string(dirty));
+	if (wanted != le32_to_cpu(grant->wanted)) {
+		dout("mds wanted %s -> %s\n",
+		     ceph_cap_string(le32_to_cpu(grant->wanted)),
+		     ceph_cap_string(wanted));
+		/* imported cap may not have correct mds_wanted */
+		if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT)
+			check_caps = 1;
+	}
+
+	/* revocation, grant, or no-op? */
+	if (cap->issued & ~newcaps) {
+		int revoking = cap->issued & ~newcaps;
+
+		dout("revocation: %s -> %s (revoking %s)\n",
+		     ceph_cap_string(cap->issued),
+		     ceph_cap_string(newcaps),
+		     ceph_cap_string(revoking));
+		if (revoking & used & CEPH_CAP_FILE_BUFFER)
+			writeback = true;  /* initiate writeback; will delay ack */
+		else if (revoking == CEPH_CAP_FILE_CACHE &&
+			 (newcaps & CEPH_CAP_FILE_LAZYIO) == 0 &&
+			 queue_invalidate)
+			; /* do nothing yet, invalidation will be queued */
+		else if (cap == ci->i_auth_cap)
+			check_caps = 1; /* check auth cap only */
+		else
+			check_caps = 2; /* check all caps */
+		cap->issued = newcaps;
+		cap->implemented |= newcaps;
+	} else if (cap->issued == newcaps) {
+		dout("caps unchanged: %s -> %s\n",
+		     ceph_cap_string(cap->issued), ceph_cap_string(newcaps));
+	} else {
+		dout("grant: %s -> %s\n", ceph_cap_string(cap->issued),
+		     ceph_cap_string(newcaps));
+		/* non-auth MDS is revoking the newly grant caps ? */
+		if (cap == ci->i_auth_cap &&
+		    __ceph_caps_revoking_other(ci, cap, newcaps))
+		    check_caps = 2;
+
+		cap->issued = newcaps;
+		cap->implemented |= newcaps; /* add bits only, to
+					      * avoid stepping on a
+					      * pending revocation */
+		wake = true;
+	}
+	BUG_ON(cap->issued & ~cap->implemented);
+
+	if (inline_version > 0 && inline_version >= ci->i_inline_version) {
+		ci->i_inline_version = inline_version;
+		if (ci->i_inline_version != CEPH_INLINE_NONE &&
+		    (newcaps & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)))
+			fill_inline = true;
+	}
+
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (le32_to_cpu(grant->op) == CEPH_CAP_OP_IMPORT) {
+		kick_flushing_inode_caps(mdsc, session, inode);
+		up_read(&mdsc->snap_rwsem);
+		if (newcaps & ~issued)
+			wake = true;
+	}
+
+	if (fill_inline)
+		ceph_fill_inline_data(inode, NULL, inline_data, inline_len);
+
+	if (queue_trunc) {
+		ceph_queue_vmtruncate(inode);
+		ceph_queue_revalidate(inode);
+	} else if (queue_revalidate)
+		ceph_queue_revalidate(inode);
+
+	if (writeback)
+		/*
+		 * queue inode for writeback: we can't actually call
+		 * filemap_write_and_wait, etc. from message handler
+		 * context.
+		 */
+		ceph_queue_writeback(inode);
+	if (queue_invalidate)
+		ceph_queue_invalidate(inode);
+	if (deleted_inode)
+		invalidate_aliases(inode);
+	if (wake)
+		wake_up_all(&ci->i_cap_wq);
+
+	if (check_caps == 1)
+		ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_AUTHONLY,
+				session);
+	else if (check_caps == 2)
+		ceph_check_caps(ci, CHECK_CAPS_NODELAY, session);
+	else
+		mutex_unlock(&session->s_mutex);
+}
+
+/*
+ * Handle FLUSH_ACK from MDS, indicating that metadata we sent to the
+ * MDS has been safely committed.
+ */
+static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
+				 struct ceph_mds_caps *m,
+				 struct ceph_mds_session *session,
+				 struct ceph_cap *cap)
+	__releases(ci->i_ceph_lock)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+	unsigned seq = le32_to_cpu(m->seq);
+	int dirty = le32_to_cpu(m->dirty);
+	int cleaned = 0;
+	int drop = 0;
+	int i;
+
+	for (i = 0; i < CEPH_CAP_BITS; i++)
+		if ((dirty & (1 << i)) &&
+		    (u16)flush_tid == ci->i_cap_flush_tid[i])
+			cleaned |= 1 << i;
+
+	dout("handle_cap_flush_ack inode %p mds%d seq %d on %s cleaned %s,"
+	     " flushing %s -> %s\n",
+	     inode, session->s_mds, seq, ceph_cap_string(dirty),
+	     ceph_cap_string(cleaned), ceph_cap_string(ci->i_flushing_caps),
+	     ceph_cap_string(ci->i_flushing_caps & ~cleaned));
+
+	if (ci->i_flushing_caps == (ci->i_flushing_caps & ~cleaned))
+		goto out;
+
+	ci->i_flushing_caps &= ~cleaned;
+
+	spin_lock(&mdsc->cap_dirty_lock);
+	if (ci->i_flushing_caps == 0) {
+		list_del_init(&ci->i_flushing_item);
+		if (!list_empty(&session->s_cap_flushing))
+			dout(" mds%d still flushing cap on %p\n",
+			     session->s_mds,
+			     &list_entry(session->s_cap_flushing.next,
+					 struct ceph_inode_info,
+					 i_flushing_item)->vfs_inode);
+		mdsc->num_cap_flushing--;
+		wake_up_all(&mdsc->cap_flushing_wq);
+		dout(" inode %p now !flushing\n", inode);
+
+		if (ci->i_dirty_caps == 0) {
+			dout(" inode %p now clean\n", inode);
+			BUG_ON(!list_empty(&ci->i_dirty_item));
+			drop = 1;
+			if (ci->i_wrbuffer_ref_head == 0) {
+				BUG_ON(!ci->i_head_snapc);
+				ceph_put_snap_context(ci->i_head_snapc);
+				ci->i_head_snapc = NULL;
+			}
+		} else {
+			BUG_ON(list_empty(&ci->i_dirty_item));
+		}
+	}
+	spin_unlock(&mdsc->cap_dirty_lock);
+	wake_up_all(&ci->i_cap_wq);
+
+out:
+	spin_unlock(&ci->i_ceph_lock);
+	if (drop)
+		iput(inode);
+}
+
+/*
+ * Handle FLUSHSNAP_ACK.  MDS has flushed snap data to disk and we can
+ * throw away our cap_snap.
+ *
+ * Caller hold s_mutex.
+ */
+static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
+				     struct ceph_mds_caps *m,
+				     struct ceph_mds_session *session)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	u64 follows = le64_to_cpu(m->snap_follows);
+	struct ceph_cap_snap *capsnap;
+	int drop = 0;
+
+	dout("handle_cap_flushsnap_ack inode %p ci %p mds%d follows %lld\n",
+	     inode, ci, session->s_mds, follows);
+
+	spin_lock(&ci->i_ceph_lock);
+	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
+		if (capsnap->follows == follows) {
+			if (capsnap->flush_tid != flush_tid) {
+				dout(" cap_snap %p follows %lld tid %lld !="
+				     " %lld\n", capsnap, follows,
+				     flush_tid, capsnap->flush_tid);
+				break;
+			}
+			WARN_ON(capsnap->dirty_pages || capsnap->writing);
+			dout(" removing %p cap_snap %p follows %lld\n",
+			     inode, capsnap, follows);
+			ceph_put_snap_context(capsnap->context);
+			list_del(&capsnap->ci_item);
+			list_del(&capsnap->flushing_item);
+			ceph_put_cap_snap(capsnap);
+			drop = 1;
+			break;
+		} else {
+			dout(" skipping cap_snap %p follows %lld\n",
+			     capsnap, capsnap->follows);
+		}
+	}
+	spin_unlock(&ci->i_ceph_lock);
+	if (drop)
+		iput(inode);
+}
+
+/*
+ * Handle TRUNC from MDS, indicating file truncation.
+ *
+ * caller hold s_mutex.
+ */
+static void handle_cap_trunc(struct inode *inode,
+			     struct ceph_mds_caps *trunc,
+			     struct ceph_mds_session *session)
+	__releases(ci->i_ceph_lock)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int mds = session->s_mds;
+	int seq = le32_to_cpu(trunc->seq);
+	u32 truncate_seq = le32_to_cpu(trunc->truncate_seq);
+	u64 truncate_size = le64_to_cpu(trunc->truncate_size);
+	u64 size = le64_to_cpu(trunc->size);
+	int implemented = 0;
+	int dirty = __ceph_caps_dirty(ci);
+	int issued = __ceph_caps_issued(ceph_inode(inode), &implemented);
+	int queue_trunc = 0;
+
+	issued |= implemented | dirty;
+
+	dout("handle_cap_trunc inode %p mds%d seq %d to %lld seq %d\n",
+	     inode, mds, seq, truncate_size, truncate_seq);
+	queue_trunc = ceph_fill_file_size(inode, issued,
+					  truncate_seq, truncate_size, size);
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (queue_trunc) {
+		ceph_queue_vmtruncate(inode);
+		ceph_fscache_invalidate(inode);
+	}
+}
+
+/*
+ * Handle EXPORT from MDS.  Cap is being migrated _from_ this mds to a
+ * different one.  If we are the most recent migration we've seen (as
+ * indicated by mseq), make note of the migrating cap bits for the
+ * duration (until we see the corresponding IMPORT).
+ *
+ * caller holds s_mutex
+ */
+static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
+			      struct ceph_mds_cap_peer *ph,
+			      struct ceph_mds_session *session)
+{
+	struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
+	struct ceph_mds_session *tsession = NULL;
+	struct ceph_cap *cap, *tcap, *new_cap = NULL;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	u64 t_cap_id;
+	unsigned mseq = le32_to_cpu(ex->migrate_seq);
+	unsigned t_seq, t_mseq;
+	int target, issued;
+	int mds = session->s_mds;
+
+	if (ph) {
+		t_cap_id = le64_to_cpu(ph->cap_id);
+		t_seq = le32_to_cpu(ph->seq);
+		t_mseq = le32_to_cpu(ph->mseq);
+		target = le32_to_cpu(ph->mds);
+	} else {
+		t_cap_id = t_seq = t_mseq = 0;
+		target = -1;
+	}
+
+	dout("handle_cap_export inode %p ci %p mds%d mseq %d target %d\n",
+	     inode, ci, mds, mseq, target);
+retry:
+	spin_lock(&ci->i_ceph_lock);
+	cap = __get_cap_for_mds(ci, mds);
+	if (!cap || cap->cap_id != le64_to_cpu(ex->cap_id))
+		goto out_unlock;
+
+	if (target < 0) {
+		__ceph_remove_cap(cap, false);
+		goto out_unlock;
+	}
+
+	/*
+	 * now we know we haven't received the cap import message yet
+	 * because the exported cap still exist.
+	 */
+
+	issued = cap->issued;
+	WARN_ON(issued != cap->implemented);
+
+	tcap = __get_cap_for_mds(ci, target);
+	if (tcap) {
+		/* already have caps from the target */
+		if (tcap->cap_id != t_cap_id ||
+		    ceph_seq_cmp(tcap->seq, t_seq) < 0) {
+			dout(" updating import cap %p mds%d\n", tcap, target);
+			tcap->cap_id = t_cap_id;
+			tcap->seq = t_seq - 1;
+			tcap->issue_seq = t_seq - 1;
+			tcap->mseq = t_mseq;
+			tcap->issued |= issued;
+			tcap->implemented |= issued;
+			if (cap == ci->i_auth_cap)
+				ci->i_auth_cap = tcap;
+			if (ci->i_flushing_caps && ci->i_auth_cap == tcap) {
+				spin_lock(&mdsc->cap_dirty_lock);
+				list_move_tail(&ci->i_flushing_item,
+					       &tcap->session->s_cap_flushing);
+				spin_unlock(&mdsc->cap_dirty_lock);
+			}
+		}
+		__ceph_remove_cap(cap, false);
+		goto out_unlock;
+	} else if (tsession) {
+		/* add placeholder for the export tagert */
+		int flag = (cap == ci->i_auth_cap) ? CEPH_CAP_FLAG_AUTH : 0;
+		ceph_add_cap(inode, tsession, t_cap_id, -1, issued, 0,
+			     t_seq - 1, t_mseq, (u64)-1, flag, &new_cap);
+
+		__ceph_remove_cap(cap, false);
+		goto out_unlock;
+	}
+
+	spin_unlock(&ci->i_ceph_lock);
+	mutex_unlock(&session->s_mutex);
+
+	/* open target session */
+	tsession = ceph_mdsc_open_export_target_session(mdsc, target);
+	if (!IS_ERR(tsession)) {
+		if (mds > target) {
+			mutex_lock(&session->s_mutex);
+			mutex_lock_nested(&tsession->s_mutex,
+					  SINGLE_DEPTH_NESTING);
+		} else {
+			mutex_lock(&tsession->s_mutex);
+			mutex_lock_nested(&session->s_mutex,
+					  SINGLE_DEPTH_NESTING);
+		}
+		ceph_add_cap_releases(mdsc, tsession);
+		new_cap = ceph_get_cap(mdsc, NULL);
+	} else {
+		WARN_ON(1);
+		tsession = NULL;
+		target = -1;
+	}
+	goto retry;
+
+out_unlock:
+	spin_unlock(&ci->i_ceph_lock);
+	mutex_unlock(&session->s_mutex);
+	if (tsession) {
+		mutex_unlock(&tsession->s_mutex);
+		ceph_put_mds_session(tsession);
+	}
+	if (new_cap)
+		ceph_put_cap(mdsc, new_cap);
+}
+
+/*
+ * Handle cap IMPORT.
+ *
+ * caller holds s_mutex. acquires i_ceph_lock
+ */
+static void handle_cap_import(struct ceph_mds_client *mdsc,
+			      struct inode *inode, struct ceph_mds_caps *im,
+			      struct ceph_mds_cap_peer *ph,
+			      struct ceph_mds_session *session,
+			      struct ceph_cap **target_cap, int *old_issued)
+	__acquires(ci->i_ceph_lock)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_cap *cap, *ocap, *new_cap = NULL;
+	int mds = session->s_mds;
+	int issued;
+	unsigned caps = le32_to_cpu(im->caps);
+	unsigned wanted = le32_to_cpu(im->wanted);
+	unsigned seq = le32_to_cpu(im->seq);
+	unsigned mseq = le32_to_cpu(im->migrate_seq);
+	u64 realmino = le64_to_cpu(im->realm);
+	u64 cap_id = le64_to_cpu(im->cap_id);
+	u64 p_cap_id;
+	int peer;
+
+	if (ph) {
+		p_cap_id = le64_to_cpu(ph->cap_id);
+		peer = le32_to_cpu(ph->mds);
+	} else {
+		p_cap_id = 0;
+		peer = -1;
+	}
+
+	dout("handle_cap_import inode %p ci %p mds%d mseq %d peer %d\n",
+	     inode, ci, mds, mseq, peer);
+
+retry:
+	spin_lock(&ci->i_ceph_lock);
+	cap = __get_cap_for_mds(ci, mds);
+	if (!cap) {
+		if (!new_cap) {
+			spin_unlock(&ci->i_ceph_lock);
+			new_cap = ceph_get_cap(mdsc, NULL);
+			goto retry;
+		}
+		cap = new_cap;
+	} else {
+		if (new_cap) {
+			ceph_put_cap(mdsc, new_cap);
+			new_cap = NULL;
+		}
+	}
+
+	__ceph_caps_issued(ci, &issued);
+	issued |= __ceph_caps_dirty(ci);
+
+	ceph_add_cap(inode, session, cap_id, -1, caps, wanted, seq, mseq,
+		     realmino, CEPH_CAP_FLAG_AUTH, &new_cap);
+
+	ocap = peer >= 0 ? __get_cap_for_mds(ci, peer) : NULL;
+	if (ocap && ocap->cap_id == p_cap_id) {
+		dout(" remove export cap %p mds%d flags %d\n",
+		     ocap, peer, ph->flags);
+		if ((ph->flags & CEPH_CAP_FLAG_AUTH) &&
+		    (ocap->seq != le32_to_cpu(ph->seq) ||
+		     ocap->mseq != le32_to_cpu(ph->mseq))) {
+			pr_err("handle_cap_import: mismatched seq/mseq: "
+			       "ino (%llx.%llx) mds%d seq %d mseq %d "
+			       "importer mds%d has peer seq %d mseq %d\n",
+			       ceph_vinop(inode), peer, ocap->seq,
+			       ocap->mseq, mds, le32_to_cpu(ph->seq),
+			       le32_to_cpu(ph->mseq));
+		}
+		__ceph_remove_cap(ocap, (ph->flags & CEPH_CAP_FLAG_RELEASE));
+	}
+
+	/* make sure we re-request max_size, if necessary */
+	ci->i_wanted_max_size = 0;
+	ci->i_requested_max_size = 0;
+
+	*old_issued = issued;
+	*target_cap = cap;
+}
+
+/*
+ * Handle a caps message from the MDS.
+ *
+ * Identify the appropriate session, inode, and call the right handler
+ * based on the cap op.
+ */
+void ceph_handle_caps(struct ceph_mds_session *session,
+		      struct ceph_msg *msg)
+{
+	struct ceph_mds_client *mdsc = session->s_mdsc;
+	struct super_block *sb = mdsc->fsc->sb;
+	struct inode *inode;
+	struct ceph_inode_info *ci;
+	struct ceph_cap *cap;
+	struct ceph_mds_caps *h;
+	struct ceph_mds_cap_peer *peer = NULL;
+	struct ceph_snap_realm *realm;
+	int mds = session->s_mds;
+	int op, issued;
+	u32 seq, mseq;
+	struct ceph_vino vino;
+	u64 cap_id;
+	u64 size, max_size;
+	u64 tid;
+	u64 inline_version = 0;
+	void *inline_data = NULL;
+	u32  inline_len = 0;
+	void *snaptrace;
+	size_t snaptrace_len;
+	void *p, *end;
+
+	dout("handle_caps from mds%d\n", mds);
+
+	/* decode */
+	end = msg->front.iov_base + msg->front.iov_len;
+	tid = le64_to_cpu(msg->hdr.tid);
+	if (msg->front.iov_len < sizeof(*h))
+		goto bad;
+	h = msg->front.iov_base;
+	op = le32_to_cpu(h->op);
+	vino.ino = le64_to_cpu(h->ino);
+	vino.snap = CEPH_NOSNAP;
+	cap_id = le64_to_cpu(h->cap_id);
+	seq = le32_to_cpu(h->seq);
+	mseq = le32_to_cpu(h->migrate_seq);
+	size = le64_to_cpu(h->size);
+	max_size = le64_to_cpu(h->max_size);
+
+	snaptrace = h + 1;
+	snaptrace_len = le32_to_cpu(h->snap_trace_len);
+	p = snaptrace + snaptrace_len;
+
+	if (le16_to_cpu(msg->hdr.version) >= 2) {
+		u32 flock_len;
+		ceph_decode_32_safe(&p, end, flock_len, bad);
+		if (p + flock_len > end)
+			goto bad;
+		p += flock_len;
+	}
+
+	if (le16_to_cpu(msg->hdr.version) >= 3) {
+		if (op == CEPH_CAP_OP_IMPORT) {
+			if (p + sizeof(*peer) > end)
+				goto bad;
+			peer = p;
+			p += sizeof(*peer);
+		} else if (op == CEPH_CAP_OP_EXPORT) {
+			/* recorded in unused fields */
+			peer = (void *)&h->size;
+		}
+	}
+
+	if (le16_to_cpu(msg->hdr.version) >= 4) {
+		ceph_decode_64_safe(&p, end, inline_version, bad);
+		ceph_decode_32_safe(&p, end, inline_len, bad);
+		if (p + inline_len > end)
+			goto bad;
+		inline_data = p;
+		p += inline_len;
+	}
+
+	/* lookup ino */
+	inode = ceph_find_inode(sb, vino);
+	ci = ceph_inode(inode);
+	dout(" op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op), vino.ino,
+	     vino.snap, inode);
+
+	mutex_lock(&session->s_mutex);
+	session->s_seq++;
+	dout(" mds%d seq %lld cap seq %u\n", session->s_mds, session->s_seq,
+	     (unsigned)seq);
+
+	if (op == CEPH_CAP_OP_IMPORT)
+		ceph_add_cap_releases(mdsc, session);
+
+	if (!inode) {
+		dout(" i don't have ino %llx\n", vino.ino);
+
+		if (op == CEPH_CAP_OP_IMPORT) {
+			spin_lock(&session->s_cap_lock);
+			__queue_cap_release(session, vino.ino, cap_id,
+					    mseq, seq);
+			spin_unlock(&session->s_cap_lock);
+		}
+		goto flush_cap_releases;
+	}
+
+	/* these will work even if we don't have a cap yet */
+	switch (op) {
+	case CEPH_CAP_OP_FLUSHSNAP_ACK:
+		handle_cap_flushsnap_ack(inode, tid, h, session);
+		goto done;
+
+	case CEPH_CAP_OP_EXPORT:
+		handle_cap_export(inode, h, peer, session);
+		goto done_unlocked;
+
+	case CEPH_CAP_OP_IMPORT:
+		realm = NULL;
+		if (snaptrace_len) {
+			down_write(&mdsc->snap_rwsem);
+			ceph_update_snap_trace(mdsc, snaptrace,
+					       snaptrace + snaptrace_len,
+					       false, &realm);
+			downgrade_write(&mdsc->snap_rwsem);
+		} else {
+			down_read(&mdsc->snap_rwsem);
+		}
+		handle_cap_import(mdsc, inode, h, peer, session,
+				  &cap, &issued);
+		handle_cap_grant(mdsc, inode, h,
+				 inline_version, inline_data, inline_len,
+				 msg->middle, session, cap, issued);
+		if (realm)
+			ceph_put_snap_realm(mdsc, realm);
+		goto done_unlocked;
+	}
+
+	/* the rest require a cap */
+	spin_lock(&ci->i_ceph_lock);
+	cap = __get_cap_for_mds(ceph_inode(inode), mds);
+	if (!cap) {
+		dout(" no cap on %p ino %llx.%llx from mds%d\n",
+		     inode, ceph_ino(inode), ceph_snap(inode), mds);
+		spin_unlock(&ci->i_ceph_lock);
+		goto flush_cap_releases;
+	}
+
+	/* note that each of these drops i_ceph_lock for us */
+	switch (op) {
+	case CEPH_CAP_OP_REVOKE:
+	case CEPH_CAP_OP_GRANT:
+		__ceph_caps_issued(ci, &issued);
+		issued |= __ceph_caps_dirty(ci);
+		handle_cap_grant(mdsc, inode, h,
+				 inline_version, inline_data, inline_len,
+				 msg->middle, session, cap, issued);
+		goto done_unlocked;
+
+	case CEPH_CAP_OP_FLUSH_ACK:
+		handle_cap_flush_ack(inode, tid, h, session, cap);
+		break;
+
+	case CEPH_CAP_OP_TRUNC:
+		handle_cap_trunc(inode, h, session);
+		break;
+
+	default:
+		spin_unlock(&ci->i_ceph_lock);
+		pr_err("ceph_handle_caps: unknown cap op %d %s\n", op,
+		       ceph_cap_op_name(op));
+	}
+
+	goto done;
+
+flush_cap_releases:
+	/*
+	 * send any full release message to try to move things
+	 * along for the mds (who clearly thinks we still have this
+	 * cap).
+	 */
+	ceph_add_cap_releases(mdsc, session);
+	ceph_send_cap_releases(mdsc, session);
+
+done:
+	mutex_unlock(&session->s_mutex);
+done_unlocked:
+	iput(inode);
+	return;
+
+bad:
+	pr_err("ceph_handle_caps: corrupt message\n");
+	ceph_msg_dump(msg);
+	return;
+}
+
+/*
+ * Delayed work handler to process end of delayed cap release LRU list.
+ */
+void ceph_check_delayed_caps(struct ceph_mds_client *mdsc)
+{
+	struct ceph_inode_info *ci;
+	int flags = CHECK_CAPS_NODELAY;
+
+	dout("check_delayed_caps\n");
+	while (1) {
+		spin_lock(&mdsc->cap_delay_lock);
+		if (list_empty(&mdsc->cap_delay_list))
+			break;
+		ci = list_first_entry(&mdsc->cap_delay_list,
+				      struct ceph_inode_info,
+				      i_cap_delay_list);
+		if ((ci->i_ceph_flags & CEPH_I_FLUSH) == 0 &&
+		    time_before(jiffies, ci->i_hold_caps_max))
+			break;
+		list_del_init(&ci->i_cap_delay_list);
+		spin_unlock(&mdsc->cap_delay_lock);
+		dout("check_delayed_caps on %p\n", &ci->vfs_inode);
+		ceph_check_caps(ci, flags, NULL);
+	}
+	spin_unlock(&mdsc->cap_delay_lock);
+}
+
+/*
+ * Flush all dirty caps to the mds
+ */
+void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
+{
+	struct ceph_inode_info *ci;
+	struct inode *inode;
+
+	dout("flush_dirty_caps\n");
+	spin_lock(&mdsc->cap_dirty_lock);
+	while (!list_empty(&mdsc->cap_dirty)) {
+		ci = list_first_entry(&mdsc->cap_dirty, struct ceph_inode_info,
+				      i_dirty_item);
+		inode = &ci->vfs_inode;
+		ihold(inode);
+		dout("flush_dirty_caps %p\n", inode);
+		spin_unlock(&mdsc->cap_dirty_lock);
+		ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_FLUSH, NULL);
+		iput(inode);
+		spin_lock(&mdsc->cap_dirty_lock);
+	}
+	spin_unlock(&mdsc->cap_dirty_lock);
+	dout("flush_dirty_caps done\n");
+}
+
+/*
+ * Drop open file reference.  If we were the last open file,
+ * we may need to release capabilities to the MDS (or schedule
+ * their delayed release).
+ */
+void ceph_put_fmode(struct ceph_inode_info *ci, int fmode)
+{
+	struct inode *inode = &ci->vfs_inode;
+	int last = 0;
+
+	spin_lock(&ci->i_ceph_lock);
+	dout("put_fmode %p fmode %d %d -> %d\n", inode, fmode,
+	     ci->i_nr_by_mode[fmode], ci->i_nr_by_mode[fmode]-1);
+	BUG_ON(ci->i_nr_by_mode[fmode] == 0);
+	if (--ci->i_nr_by_mode[fmode] == 0)
+		last++;
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (last && ci->i_vino.snap == CEPH_NOSNAP)
+		ceph_check_caps(ci, 0, NULL);
+}
+
+/*
+ * Helpers for embedding cap and dentry lease releases into mds
+ * requests.
+ *
+ * @force is used by dentry_release (below) to force inclusion of a
+ * record for the directory inode, even when there aren't any caps to
+ * drop.
+ */
+int ceph_encode_inode_release(void **p, struct inode *inode,
+			      int mds, int drop, int unless, int force)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_cap *cap;
+	struct ceph_mds_request_release *rel = *p;
+	int used, dirty;
+	int ret = 0;
+
+	spin_lock(&ci->i_ceph_lock);
+	used = __ceph_caps_used(ci);
+	dirty = __ceph_caps_dirty(ci);
+
+	dout("encode_inode_release %p mds%d used|dirty %s drop %s unless %s\n",
+	     inode, mds, ceph_cap_string(used|dirty), ceph_cap_string(drop),
+	     ceph_cap_string(unless));
+
+	/* only drop unused, clean caps */
+	drop &= ~(used | dirty);
+
+	cap = __get_cap_for_mds(ci, mds);
+	if (cap && __cap_is_valid(cap)) {
+		if (force ||
+		    ((cap->issued & drop) &&
+		     (cap->issued & unless) == 0)) {
+			if ((cap->issued & drop) &&
+			    (cap->issued & unless) == 0) {
+				int wanted = __ceph_caps_wanted(ci);
+				if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0)
+					wanted |= cap->mds_wanted;
+				dout("encode_inode_release %p cap %p "
+				     "%s -> %s, wanted %s -> %s\n", inode, cap,
+				     ceph_cap_string(cap->issued),
+				     ceph_cap_string(cap->issued & ~drop),
+				     ceph_cap_string(cap->mds_wanted),
+				     ceph_cap_string(wanted));
+
+				cap->issued &= ~drop;
+				cap->implemented &= ~drop;
+				cap->mds_wanted = wanted;
+			} else {
+				dout("encode_inode_release %p cap %p %s"
+				     " (force)\n", inode, cap,
+				     ceph_cap_string(cap->issued));
+			}
+
+			rel->ino = cpu_to_le64(ceph_ino(inode));
+			rel->cap_id = cpu_to_le64(cap->cap_id);
+			rel->seq = cpu_to_le32(cap->seq);
+			rel->issue_seq = cpu_to_le32(cap->issue_seq);
+			rel->mseq = cpu_to_le32(cap->mseq);
+			rel->caps = cpu_to_le32(cap->implemented);
+			rel->wanted = cpu_to_le32(cap->mds_wanted);
+			rel->dname_len = 0;
+			rel->dname_seq = 0;
+			*p += sizeof(*rel);
+			ret = 1;
+		} else {
+			dout("encode_inode_release %p cap %p %s\n",
+			     inode, cap, ceph_cap_string(cap->issued));
+		}
+	}
+	spin_unlock(&ci->i_ceph_lock);
+	return ret;
+}
+
+int ceph_encode_dentry_release(void **p, struct dentry *dentry,
+			       int mds, int drop, int unless)
+{
+	struct inode *dir = d_inode(dentry->d_parent);
+	struct ceph_mds_request_release *rel = *p;
+	struct ceph_dentry_info *di = ceph_dentry(dentry);
+	int force = 0;
+	int ret;
+
+	/*
+	 * force an record for the directory caps if we have a dentry lease.
+	 * this is racy (can't take i_ceph_lock and d_lock together), but it
+	 * doesn't have to be perfect; the mds will revoke anything we don't
+	 * release.
+	 */
+	spin_lock(&dentry->d_lock);
+	if (di->lease_session && di->lease_session->s_mds == mds)
+		force = 1;
+	spin_unlock(&dentry->d_lock);
+
+	ret = ceph_encode_inode_release(p, dir, mds, drop, unless, force);
+
+	spin_lock(&dentry->d_lock);
+	if (ret && di->lease_session && di->lease_session->s_mds == mds) {
+		dout("encode_dentry_release %p mds%d seq %d\n",
+		     dentry, mds, (int)di->lease_seq);
+		rel->dname_len = cpu_to_le32(dentry->d_name.len);
+		memcpy(*p, dentry->d_name.name, dentry->d_name.len);
+		*p += dentry->d_name.len;
+		rel->dname_seq = cpu_to_le32(di->lease_seq);
+		__ceph_mdsc_drop_dentry_lease(dentry);
+	}
+	spin_unlock(&dentry->d_lock);
+	return ret;
+}
diff --git a/fs/ceph/ceph_frag.c b/fs/ceph/ceph_frag.c
new file mode 100644
index 000000000..bdce8b1fb
--- /dev/null
+++ b/fs/ceph/ceph_frag.c
@@ -0,0 +1,22 @@
+/*
+ * Ceph 'frag' type
+ */
+#include <linux/module.h>
+#include <linux/ceph/types.h>
+
+int ceph_frag_compare(__u32 a, __u32 b)
+{
+	unsigned va = ceph_frag_value(a);
+	unsigned vb = ceph_frag_value(b);
+	if (va < vb)
+		return -1;
+	if (va > vb)
+		return 1;
+	va = ceph_frag_bits(a);
+	vb = ceph_frag_bits(b);
+	if (va < vb)
+		return -1;
+	if (va > vb)
+		return 1;
+	return 0;
+}
diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
new file mode 100644
index 000000000..31f831471
--- /dev/null
+++ b/fs/ceph/debugfs.c
@@ -0,0 +1,321 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include <linux/ceph/libceph.h>
+#include <linux/ceph/mon_client.h>
+#include <linux/ceph/auth.h>
+#include <linux/ceph/debugfs.h>
+
+#include "super.h"
+
+#ifdef CONFIG_DEBUG_FS
+
+#include "mds_client.h"
+
+static int mdsmap_show(struct seq_file *s, void *p)
+{
+	int i;
+	struct ceph_fs_client *fsc = s->private;
+
+	if (fsc->mdsc == NULL || fsc->mdsc->mdsmap == NULL)
+		return 0;
+	seq_printf(s, "epoch %d\n", fsc->mdsc->mdsmap->m_epoch);
+	seq_printf(s, "root %d\n", fsc->mdsc->mdsmap->m_root);
+	seq_printf(s, "session_timeout %d\n",
+		       fsc->mdsc->mdsmap->m_session_timeout);
+	seq_printf(s, "session_autoclose %d\n",
+		       fsc->mdsc->mdsmap->m_session_autoclose);
+	for (i = 0; i < fsc->mdsc->mdsmap->m_max_mds; i++) {
+		struct ceph_entity_addr *addr =
+			&fsc->mdsc->mdsmap->m_info[i].addr;
+		int state = fsc->mdsc->mdsmap->m_info[i].state;
+
+		seq_printf(s, "\tmds%d\t%s\t(%s)\n", i,
+			       ceph_pr_addr(&addr->in_addr),
+			       ceph_mds_state_name(state));
+	}
+	return 0;
+}
+
+/*
+ * mdsc debugfs
+ */
+static int mdsc_show(struct seq_file *s, void *p)
+{
+	struct ceph_fs_client *fsc = s->private;
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	struct rb_node *rp;
+	int pathlen;
+	u64 pathbase;
+	char *path;
+
+	mutex_lock(&mdsc->mutex);
+	for (rp = rb_first(&mdsc->request_tree); rp; rp = rb_next(rp)) {
+		req = rb_entry(rp, struct ceph_mds_request, r_node);
+
+		if (req->r_request && req->r_session)
+			seq_printf(s, "%lld\tmds%d\t", req->r_tid,
+				   req->r_session->s_mds);
+		else if (!req->r_request)
+			seq_printf(s, "%lld\t(no request)\t", req->r_tid);
+		else
+			seq_printf(s, "%lld\t(no session)\t", req->r_tid);
+
+		seq_printf(s, "%s", ceph_mds_op_name(req->r_op));
+
+		if (req->r_got_unsafe)
+			seq_puts(s, "\t(unsafe)");
+		else
+			seq_puts(s, "\t");
+
+		if (req->r_inode) {
+			seq_printf(s, " #%llx", ceph_ino(req->r_inode));
+		} else if (req->r_dentry) {
+			path = ceph_mdsc_build_path(req->r_dentry, &pathlen,
+						    &pathbase, 0);
+			if (IS_ERR(path))
+				path = NULL;
+			spin_lock(&req->r_dentry->d_lock);
+			seq_printf(s, " #%llx/%pd (%s)",
+				   ceph_ino(d_inode(req->r_dentry->d_parent)),
+				   req->r_dentry,
+				   path ? path : "");
+			spin_unlock(&req->r_dentry->d_lock);
+			kfree(path);
+		} else if (req->r_path1) {
+			seq_printf(s, " #%llx/%s", req->r_ino1.ino,
+				   req->r_path1);
+		} else {
+			seq_printf(s, " #%llx", req->r_ino1.ino);
+		}
+
+		if (req->r_old_dentry) {
+			path = ceph_mdsc_build_path(req->r_old_dentry, &pathlen,
+						    &pathbase, 0);
+			if (IS_ERR(path))
+				path = NULL;
+			spin_lock(&req->r_old_dentry->d_lock);
+			seq_printf(s, " #%llx/%pd (%s)",
+				   req->r_old_dentry_dir ?
+				   ceph_ino(req->r_old_dentry_dir) : 0,
+				   req->r_old_dentry,
+				   path ? path : "");
+			spin_unlock(&req->r_old_dentry->d_lock);
+			kfree(path);
+		} else if (req->r_path2) {
+			if (req->r_ino2.ino)
+				seq_printf(s, " #%llx/%s", req->r_ino2.ino,
+					   req->r_path2);
+			else
+				seq_printf(s, " %s", req->r_path2);
+		}
+
+		seq_puts(s, "\n");
+	}
+	mutex_unlock(&mdsc->mutex);
+
+	return 0;
+}
+
+static int caps_show(struct seq_file *s, void *p)
+{
+	struct ceph_fs_client *fsc = s->private;
+	int total, avail, used, reserved, min;
+
+	ceph_reservation_status(fsc, &total, &avail, &used, &reserved, &min);
+	seq_printf(s, "total\t\t%d\n"
+		   "avail\t\t%d\n"
+		   "used\t\t%d\n"
+		   "reserved\t%d\n"
+		   "min\t%d\n",
+		   total, avail, used, reserved, min);
+	return 0;
+}
+
+static int dentry_lru_show(struct seq_file *s, void *ptr)
+{
+	struct ceph_fs_client *fsc = s->private;
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_dentry_info *di;
+
+	spin_lock(&mdsc->dentry_lru_lock);
+	list_for_each_entry(di, &mdsc->dentry_lru, lru) {
+		struct dentry *dentry = di->dentry;
+		seq_printf(s, "%p %p\t%pd\n",
+			   di, dentry, dentry);
+	}
+	spin_unlock(&mdsc->dentry_lru_lock);
+
+	return 0;
+}
+
+static int mds_sessions_show(struct seq_file *s, void *ptr)
+{
+	struct ceph_fs_client *fsc = s->private;
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_auth_client *ac = fsc->client->monc.auth;
+	struct ceph_options *opt = fsc->client->options;
+	int mds = -1;
+
+	mutex_lock(&mdsc->mutex);
+
+	/* The 'num' portion of an 'entity name' */
+	seq_printf(s, "global_id %llu\n", ac->global_id);
+
+	/* The -o name mount argument */
+	seq_printf(s, "name \"%s\"\n", opt->name ? opt->name : "");
+
+	/* The list of MDS session rank+state */
+	for (mds = 0; mds < mdsc->max_sessions; mds++) {
+		struct ceph_mds_session *session =
+			__ceph_lookup_mds_session(mdsc, mds);
+		if (!session) {
+			continue;
+		}
+		mutex_unlock(&mdsc->mutex);
+		seq_printf(s, "mds.%d %s\n",
+				session->s_mds,
+				ceph_session_state_name(session->s_state));
+
+		ceph_put_mds_session(session);
+		mutex_lock(&mdsc->mutex);
+	}
+	mutex_unlock(&mdsc->mutex);
+
+	return 0;
+}
+
+CEPH_DEFINE_SHOW_FUNC(mdsmap_show)
+CEPH_DEFINE_SHOW_FUNC(mdsc_show)
+CEPH_DEFINE_SHOW_FUNC(caps_show)
+CEPH_DEFINE_SHOW_FUNC(dentry_lru_show)
+CEPH_DEFINE_SHOW_FUNC(mds_sessions_show)
+
+
+/*
+ * debugfs
+ */
+static int congestion_kb_set(void *data, u64 val)
+{
+	struct ceph_fs_client *fsc = (struct ceph_fs_client *)data;
+
+	fsc->mount_options->congestion_kb = (int)val;
+	return 0;
+}
+
+static int congestion_kb_get(void *data, u64 *val)
+{
+	struct ceph_fs_client *fsc = (struct ceph_fs_client *)data;
+
+	*val = (u64)fsc->mount_options->congestion_kb;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
+			congestion_kb_set, "%llu\n");
+
+
+void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)
+{
+	dout("ceph_fs_debugfs_cleanup\n");
+	debugfs_remove(fsc->debugfs_bdi);
+	debugfs_remove(fsc->debugfs_congestion_kb);
+	debugfs_remove(fsc->debugfs_mdsmap);
+	debugfs_remove(fsc->debugfs_mds_sessions);
+	debugfs_remove(fsc->debugfs_caps);
+	debugfs_remove(fsc->debugfs_mdsc);
+	debugfs_remove(fsc->debugfs_dentry_lru);
+}
+
+int ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
+{
+	char name[100];
+	int err = -ENOMEM;
+
+	dout("ceph_fs_debugfs_init\n");
+	BUG_ON(!fsc->client->debugfs_dir);
+	fsc->debugfs_congestion_kb =
+		debugfs_create_file("writeback_congestion_kb",
+				    0600,
+				    fsc->client->debugfs_dir,
+				    fsc,
+				    &congestion_kb_fops);
+	if (!fsc->debugfs_congestion_kb)
+		goto out;
+
+	snprintf(name, sizeof(name), "../../bdi/%s",
+		 dev_name(fsc->backing_dev_info.dev));
+	fsc->debugfs_bdi =
+		debugfs_create_symlink("bdi",
+				       fsc->client->debugfs_dir,
+				       name);
+	if (!fsc->debugfs_bdi)
+		goto out;
+
+	fsc->debugfs_mdsmap = debugfs_create_file("mdsmap",
+					0600,
+					fsc->client->debugfs_dir,
+					fsc,
+					&mdsmap_show_fops);
+	if (!fsc->debugfs_mdsmap)
+		goto out;
+
+	fsc->debugfs_mds_sessions = debugfs_create_file("mds_sessions",
+					0600,
+					fsc->client->debugfs_dir,
+					fsc,
+					&mds_sessions_show_fops);
+	if (!fsc->debugfs_mds_sessions)
+		goto out;
+
+	fsc->debugfs_mdsc = debugfs_create_file("mdsc",
+						0600,
+						fsc->client->debugfs_dir,
+						fsc,
+						&mdsc_show_fops);
+	if (!fsc->debugfs_mdsc)
+		goto out;
+
+	fsc->debugfs_caps = debugfs_create_file("caps",
+						   0400,
+						   fsc->client->debugfs_dir,
+						   fsc,
+						   &caps_show_fops);
+	if (!fsc->debugfs_caps)
+		goto out;
+
+	fsc->debugfs_dentry_lru = debugfs_create_file("dentry_lru",
+					0600,
+					fsc->client->debugfs_dir,
+					fsc,
+					&dentry_lru_show_fops);
+	if (!fsc->debugfs_dentry_lru)
+		goto out;
+
+	return 0;
+
+out:
+	ceph_fs_debugfs_cleanup(fsc);
+	return err;
+}
+
+
+#else  /* CONFIG_DEBUG_FS */
+
+int ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
+{
+	return 0;
+}
+
+void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)
+{
+}
+
+#endif  /* CONFIG_DEBUG_FS */
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
new file mode 100644
index 000000000..4248307fe
--- /dev/null
+++ b/fs/ceph/dir.c
@@ -0,0 +1,1411 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/spinlock.h>
+#include <linux/fs_struct.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+
+#include "super.h"
+#include "mds_client.h"
+
+/*
+ * Directory operations: readdir, lookup, create, link, unlink,
+ * rename, etc.
+ */
+
+/*
+ * Ceph MDS operations are specified in terms of a base ino and
+ * relative path.  Thus, the client can specify an operation on a
+ * specific inode (e.g., a getattr due to fstat(2)), or as a path
+ * relative to, say, the root directory.
+ *
+ * Normally, we limit ourselves to strict inode ops (no path component)
+ * or dentry operations (a single path component relative to an ino).  The
+ * exception to this is open_root_dentry(), which will open the mount
+ * point by name.
+ */
+
+const struct dentry_operations ceph_dentry_ops;
+
+/*
+ * Initialize ceph dentry state.
+ */
+int ceph_init_dentry(struct dentry *dentry)
+{
+	struct ceph_dentry_info *di;
+
+	if (dentry->d_fsdata)
+		return 0;
+
+	di = kmem_cache_alloc(ceph_dentry_cachep, GFP_NOFS | __GFP_ZERO);
+	if (!di)
+		return -ENOMEM;          /* oh well */
+
+	spin_lock(&dentry->d_lock);
+	if (dentry->d_fsdata) {
+		/* lost a race */
+		kmem_cache_free(ceph_dentry_cachep, di);
+		goto out_unlock;
+	}
+
+	if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_NOSNAP)
+		d_set_d_op(dentry, &ceph_dentry_ops);
+	else if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_SNAPDIR)
+		d_set_d_op(dentry, &ceph_snapdir_dentry_ops);
+	else
+		d_set_d_op(dentry, &ceph_snap_dentry_ops);
+
+	di->dentry = dentry;
+	di->lease_session = NULL;
+	dentry->d_time = jiffies;
+	/* avoid reordering d_fsdata setup so that the check above is safe */
+	smp_mb();
+	dentry->d_fsdata = di;
+	ceph_dentry_lru_add(dentry);
+out_unlock:
+	spin_unlock(&dentry->d_lock);
+	return 0;
+}
+
+struct inode *ceph_get_dentry_parent_inode(struct dentry *dentry)
+{
+	struct inode *inode = NULL;
+
+	if (!dentry)
+		return NULL;
+
+	spin_lock(&dentry->d_lock);
+	if (!IS_ROOT(dentry)) {
+		inode = d_inode(dentry->d_parent);
+		ihold(inode);
+	}
+	spin_unlock(&dentry->d_lock);
+	return inode;
+}
+
+
+/*
+ * for readdir, we encode the directory frag and offset within that
+ * frag into f_pos.
+ */
+static unsigned fpos_frag(loff_t p)
+{
+	return p >> 32;
+}
+static unsigned fpos_off(loff_t p)
+{
+	return p & 0xffffffff;
+}
+
+static int fpos_cmp(loff_t l, loff_t r)
+{
+	int v = ceph_frag_compare(fpos_frag(l), fpos_frag(r));
+	if (v)
+		return v;
+	return (int)(fpos_off(l) - fpos_off(r));
+}
+
+/*
+ * When possible, we try to satisfy a readdir by peeking at the
+ * dcache.  We make this work by carefully ordering dentries on
+ * d_child when we initially get results back from the MDS, and
+ * falling back to a "normal" sync readdir if any dentries in the dir
+ * are dropped.
+ *
+ * Complete dir indicates that we have all dentries in the dir.  It is
+ * defined IFF we hold CEPH_CAP_FILE_SHARED (which will be revoked by
+ * the MDS if/when the directory is modified).
+ */
+static int __dcache_readdir(struct file *file,  struct dir_context *ctx,
+			    u32 shared_gen)
+{
+	struct ceph_file_info *fi = file->private_data;
+	struct dentry *parent = file->f_path.dentry;
+	struct inode *dir = d_inode(parent);
+	struct list_head *p;
+	struct dentry *dentry, *last;
+	struct ceph_dentry_info *di;
+	int err = 0;
+
+	/* claim ref on last dentry we returned */
+	last = fi->dentry;
+	fi->dentry = NULL;
+
+	dout("__dcache_readdir %p v%u at %llu (last %p)\n",
+	     dir, shared_gen, ctx->pos, last);
+
+	spin_lock(&parent->d_lock);
+
+	/* start at beginning? */
+	if (ctx->pos == 2 || last == NULL ||
+	    fpos_cmp(ctx->pos, ceph_dentry(last)->offset) < 0) {
+		if (list_empty(&parent->d_subdirs))
+			goto out_unlock;
+		p = parent->d_subdirs.prev;
+		dout(" initial p %p/%p\n", p->prev, p->next);
+	} else {
+		p = last->d_child.prev;
+	}
+
+more:
+	dentry = list_entry(p, struct dentry, d_child);
+	di = ceph_dentry(dentry);
+	while (1) {
+		dout(" p %p/%p %s d_subdirs %p/%p\n", p->prev, p->next,
+		     d_unhashed(dentry) ? "!hashed" : "hashed",
+		     parent->d_subdirs.prev, parent->d_subdirs.next);
+		if (p == &parent->d_subdirs) {
+			fi->flags |= CEPH_F_ATEND;
+			goto out_unlock;
+		}
+		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
+		if (di->lease_shared_gen == shared_gen &&
+		    !d_unhashed(dentry) && d_really_is_positive(dentry) &&
+		    ceph_snap(d_inode(dentry)) != CEPH_SNAPDIR &&
+		    ceph_ino(d_inode(dentry)) != CEPH_INO_CEPH &&
+		    fpos_cmp(ctx->pos, di->offset) <= 0)
+			break;
+		dout(" skipping %p %pd at %llu (%llu)%s%s\n", dentry,
+		     dentry, di->offset,
+		     ctx->pos, d_unhashed(dentry) ? " unhashed" : "",
+		     !d_inode(dentry) ? " null" : "");
+		spin_unlock(&dentry->d_lock);
+		p = p->prev;
+		dentry = list_entry(p, struct dentry, d_child);
+		di = ceph_dentry(dentry);
+	}
+
+	dget_dlock(dentry);
+	spin_unlock(&dentry->d_lock);
+	spin_unlock(&parent->d_lock);
+
+	/* make sure a dentry wasn't dropped while we didn't have parent lock */
+	if (!ceph_dir_is_complete_ordered(dir)) {
+		dout(" lost dir complete on %p; falling back to mds\n", dir);
+		dput(dentry);
+		err = -EAGAIN;
+		goto out;
+	}
+
+	dout(" %llu (%llu) dentry %p %pd %p\n", di->offset, ctx->pos,
+	     dentry, dentry, d_inode(dentry));
+	if (!dir_emit(ctx, dentry->d_name.name,
+		      dentry->d_name.len,
+		      ceph_translate_ino(dentry->d_sb, d_inode(dentry)->i_ino),
+		      d_inode(dentry)->i_mode >> 12)) {
+		if (last) {
+			/* remember our position */
+			fi->dentry = last;
+			fi->next_offset = fpos_off(di->offset);
+		}
+		dput(dentry);
+		return 0;
+	}
+
+	ctx->pos = di->offset + 1;
+
+	if (last)
+		dput(last);
+	last = dentry;
+
+	spin_lock(&parent->d_lock);
+	p = p->prev;	/* advance to next dentry */
+	goto more;
+
+out_unlock:
+	spin_unlock(&parent->d_lock);
+out:
+	if (last)
+		dput(last);
+	return err;
+}
+
+/*
+ * make note of the last dentry we read, so we can
+ * continue at the same lexicographical point,
+ * regardless of what dir changes take place on the
+ * server.
+ */
+static int note_last_dentry(struct ceph_file_info *fi, const char *name,
+			    int len)
+{
+	kfree(fi->last_name);
+	fi->last_name = kmalloc(len+1, GFP_NOFS);
+	if (!fi->last_name)
+		return -ENOMEM;
+	memcpy(fi->last_name, name, len);
+	fi->last_name[len] = 0;
+	dout("note_last_dentry '%s'\n", fi->last_name);
+	return 0;
+}
+
+static int ceph_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct ceph_file_info *fi = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	unsigned frag = fpos_frag(ctx->pos);
+	int off = fpos_off(ctx->pos);
+	int err;
+	u32 ftype;
+	struct ceph_mds_reply_info_parsed *rinfo;
+
+	dout("readdir %p file %p frag %u off %u\n", inode, file, frag, off);
+	if (fi->flags & CEPH_F_ATEND)
+		return 0;
+
+	/* always start with . and .. */
+	if (ctx->pos == 0) {
+		dout("readdir off 0 -> '.'\n");
+		if (!dir_emit(ctx, ".", 1, 
+			    ceph_translate_ino(inode->i_sb, inode->i_ino),
+			    inode->i_mode >> 12))
+			return 0;
+		ctx->pos = 1;
+		off = 1;
+	}
+	if (ctx->pos == 1) {
+		ino_t ino = parent_ino(file->f_path.dentry);
+		dout("readdir off 1 -> '..'\n");
+		if (!dir_emit(ctx, "..", 2,
+			    ceph_translate_ino(inode->i_sb, ino),
+			    inode->i_mode >> 12))
+			return 0;
+		ctx->pos = 2;
+		off = 2;
+	}
+
+	/* can we use the dcache? */
+	spin_lock(&ci->i_ceph_lock);
+	if ((ctx->pos == 2 || fi->dentry) &&
+	    ceph_test_mount_opt(fsc, DCACHE) &&
+	    !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
+	    ceph_snap(inode) != CEPH_SNAPDIR &&
+	    __ceph_dir_is_complete_ordered(ci) &&
+	    __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
+		u32 shared_gen = ci->i_shared_gen;
+		spin_unlock(&ci->i_ceph_lock);
+		err = __dcache_readdir(file, ctx, shared_gen);
+		if (err != -EAGAIN)
+			return err;
+		frag = fpos_frag(ctx->pos);
+		off = fpos_off(ctx->pos);
+	} else {
+		spin_unlock(&ci->i_ceph_lock);
+	}
+	if (fi->dentry) {
+		err = note_last_dentry(fi, fi->dentry->d_name.name,
+				       fi->dentry->d_name.len);
+		if (err)
+			return err;
+		dput(fi->dentry);
+		fi->dentry = NULL;
+	}
+
+	/* proceed with a normal readdir */
+
+	if (ctx->pos == 2) {
+		/* note dir version at start of readdir so we can tell
+		 * if any dentries get dropped */
+		fi->dir_release_count = atomic_read(&ci->i_release_count);
+		fi->dir_ordered_count = ci->i_ordered_count;
+	}
+
+more:
+	/* do we have the correct frag content buffered? */
+	if (fi->frag != frag || fi->last_readdir == NULL) {
+		struct ceph_mds_request *req;
+		int op = ceph_snap(inode) == CEPH_SNAPDIR ?
+			CEPH_MDS_OP_LSSNAP : CEPH_MDS_OP_READDIR;
+
+		/* discard old result, if any */
+		if (fi->last_readdir) {
+			ceph_mdsc_put_request(fi->last_readdir);
+			fi->last_readdir = NULL;
+		}
+
+		dout("readdir fetching %llx.%llx frag %x offset '%s'\n",
+		     ceph_vinop(inode), frag, fi->last_name);
+		req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
+		if (IS_ERR(req))
+			return PTR_ERR(req);
+		err = ceph_alloc_readdir_reply_buffer(req, inode);
+		if (err) {
+			ceph_mdsc_put_request(req);
+			return err;
+		}
+		/* hints to request -> mds selection code */
+		req->r_direct_mode = USE_AUTH_MDS;
+		req->r_direct_hash = ceph_frag_value(frag);
+		req->r_direct_is_hash = true;
+		if (fi->last_name) {
+			req->r_path2 = kstrdup(fi->last_name, GFP_NOFS);
+			if (!req->r_path2) {
+				ceph_mdsc_put_request(req);
+				return -ENOMEM;
+			}
+		}
+		req->r_readdir_offset = fi->next_offset;
+		req->r_args.readdir.frag = cpu_to_le32(frag);
+
+		req->r_inode = inode;
+		ihold(inode);
+		req->r_dentry = dget(file->f_path.dentry);
+		err = ceph_mdsc_do_request(mdsc, NULL, req);
+		if (err < 0) {
+			ceph_mdsc_put_request(req);
+			return err;
+		}
+		dout("readdir got and parsed readdir result=%d"
+		     " on frag %x, end=%d, complete=%d\n", err, frag,
+		     (int)req->r_reply_info.dir_end,
+		     (int)req->r_reply_info.dir_complete);
+
+		if (!req->r_did_prepopulate) {
+			dout("readdir !did_prepopulate");
+			/* preclude from marking dir complete */
+			fi->dir_release_count--;
+		}
+
+		/* note next offset and last dentry name */
+		rinfo = &req->r_reply_info;
+		if (le32_to_cpu(rinfo->dir_dir->frag) != frag) {
+			frag = le32_to_cpu(rinfo->dir_dir->frag);
+			if (ceph_frag_is_leftmost(frag))
+				fi->next_offset = 2;
+			else
+				fi->next_offset = 0;
+			off = fi->next_offset;
+		}
+		fi->frag = frag;
+		fi->offset = fi->next_offset;
+		fi->last_readdir = req;
+
+		if (req->r_reply_info.dir_end) {
+			kfree(fi->last_name);
+			fi->last_name = NULL;
+			if (ceph_frag_is_rightmost(frag))
+				fi->next_offset = 2;
+			else
+				fi->next_offset = 0;
+		} else {
+			err = note_last_dentry(fi,
+				       rinfo->dir_dname[rinfo->dir_nr-1],
+				       rinfo->dir_dname_len[rinfo->dir_nr-1]);
+			if (err)
+				return err;
+			fi->next_offset += rinfo->dir_nr;
+		}
+	}
+
+	rinfo = &fi->last_readdir->r_reply_info;
+	dout("readdir frag %x num %d off %d chunkoff %d\n", frag,
+	     rinfo->dir_nr, off, fi->offset);
+
+	ctx->pos = ceph_make_fpos(frag, off);
+	while (off >= fi->offset && off - fi->offset < rinfo->dir_nr) {
+		struct ceph_mds_reply_inode *in =
+			rinfo->dir_in[off - fi->offset].in;
+		struct ceph_vino vino;
+		ino_t ino;
+
+		dout("readdir off %d (%d/%d) -> %lld '%.*s' %p\n",
+		     off, off - fi->offset, rinfo->dir_nr, ctx->pos,
+		     rinfo->dir_dname_len[off - fi->offset],
+		     rinfo->dir_dname[off - fi->offset], in);
+		BUG_ON(!in);
+		ftype = le32_to_cpu(in->mode) >> 12;
+		vino.ino = le64_to_cpu(in->ino);
+		vino.snap = le64_to_cpu(in->snapid);
+		ino = ceph_vino_to_ino(vino);
+		if (!dir_emit(ctx,
+			    rinfo->dir_dname[off - fi->offset],
+			    rinfo->dir_dname_len[off - fi->offset],
+			    ceph_translate_ino(inode->i_sb, ino), ftype)) {
+			dout("filldir stopping us...\n");
+			return 0;
+		}
+		off++;
+		ctx->pos++;
+	}
+
+	if (fi->last_name) {
+		ceph_mdsc_put_request(fi->last_readdir);
+		fi->last_readdir = NULL;
+		goto more;
+	}
+
+	/* more frags? */
+	if (!ceph_frag_is_rightmost(frag)) {
+		frag = ceph_frag_next(frag);
+		off = 0;
+		ctx->pos = ceph_make_fpos(frag, off);
+		dout("readdir next frag is %x\n", frag);
+		goto more;
+	}
+	fi->flags |= CEPH_F_ATEND;
+
+	/*
+	 * if dir_release_count still matches the dir, no dentries
+	 * were released during the whole readdir, and we should have
+	 * the complete dir contents in our cache.
+	 */
+	spin_lock(&ci->i_ceph_lock);
+	if (atomic_read(&ci->i_release_count) == fi->dir_release_count) {
+		if (ci->i_ordered_count == fi->dir_ordered_count)
+			dout(" marking %p complete and ordered\n", inode);
+		else
+			dout(" marking %p complete\n", inode);
+		__ceph_dir_set_complete(ci, fi->dir_release_count,
+					fi->dir_ordered_count);
+	}
+	spin_unlock(&ci->i_ceph_lock);
+
+	dout("readdir %p file %p done.\n", inode, file);
+	return 0;
+}
+
+static void reset_readdir(struct ceph_file_info *fi, unsigned frag)
+{
+	if (fi->last_readdir) {
+		ceph_mdsc_put_request(fi->last_readdir);
+		fi->last_readdir = NULL;
+	}
+	kfree(fi->last_name);
+	fi->last_name = NULL;
+	if (ceph_frag_is_leftmost(frag))
+		fi->next_offset = 2;  /* compensate for . and .. */
+	else
+		fi->next_offset = 0;
+	if (fi->dentry) {
+		dput(fi->dentry);
+		fi->dentry = NULL;
+	}
+	fi->flags &= ~CEPH_F_ATEND;
+}
+
+static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct ceph_file_info *fi = file->private_data;
+	struct inode *inode = file->f_mapping->host;
+	loff_t old_offset = ceph_make_fpos(fi->frag, fi->next_offset);
+	loff_t retval;
+
+	mutex_lock(&inode->i_mutex);
+	retval = -EINVAL;
+	switch (whence) {
+	case SEEK_END:
+		offset += inode->i_size + 2;   /* FIXME */
+		break;
+	case SEEK_CUR:
+		offset += file->f_pos;
+	case SEEK_SET:
+		break;
+	default:
+		goto out;
+	}
+
+	if (offset >= 0) {
+		if (offset != file->f_pos) {
+			file->f_pos = offset;
+			file->f_version = 0;
+			fi->flags &= ~CEPH_F_ATEND;
+		}
+		retval = offset;
+
+		/*
+		 * discard buffered readdir content on seekdir(0), or
+		 * seek to new frag, or seek prior to current chunk.
+		 */
+		if (offset == 0 ||
+		    fpos_frag(offset) != fi->frag ||
+		    fpos_off(offset) < fi->offset) {
+			dout("dir_llseek dropping %p content\n", file);
+			reset_readdir(fi, fpos_frag(offset));
+		}
+
+		/* bump dir_release_count if we did a forward seek */
+		if (fpos_cmp(offset, old_offset) > 0)
+			fi->dir_release_count--;
+	}
+out:
+	mutex_unlock(&inode->i_mutex);
+	return retval;
+}
+
+/*
+ * Handle lookups for the hidden .snap directory.
+ */
+int ceph_handle_snapdir(struct ceph_mds_request *req,
+			struct dentry *dentry, int err)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
+	struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */
+
+	/* .snap dir? */
+	if (err == -ENOENT &&
+	    ceph_snap(parent) == CEPH_NOSNAP &&
+	    strcmp(dentry->d_name.name,
+		   fsc->mount_options->snapdir_name) == 0) {
+		struct inode *inode = ceph_get_snapdir(parent);
+		dout("ENOENT on snapdir %p '%pd', linking to snapdir %p\n",
+		     dentry, dentry, inode);
+		BUG_ON(!d_unhashed(dentry));
+		d_add(dentry, inode);
+		err = 0;
+	}
+	return err;
+}
+
+/*
+ * Figure out final result of a lookup/open request.
+ *
+ * Mainly, make sure we return the final req->r_dentry (if it already
+ * existed) in place of the original VFS-provided dentry when they
+ * differ.
+ *
+ * Gracefully handle the case where the MDS replies with -ENOENT and
+ * no trace (which it may do, at its discretion, e.g., if it doesn't
+ * care to issue a lease on the negative dentry).
+ */
+struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
+				  struct dentry *dentry, int err)
+{
+	if (err == -ENOENT) {
+		/* no trace? */
+		err = 0;
+		if (!req->r_reply_info.head->is_dentry) {
+			dout("ENOENT and no trace, dentry %p inode %p\n",
+			     dentry, d_inode(dentry));
+			if (d_really_is_positive(dentry)) {
+				d_drop(dentry);
+				err = -ENOENT;
+			} else {
+				d_add(dentry, NULL);
+			}
+		}
+	}
+	if (err)
+		dentry = ERR_PTR(err);
+	else if (dentry != req->r_dentry)
+		dentry = dget(req->r_dentry);   /* we got spliced */
+	else
+		dentry = NULL;
+	return dentry;
+}
+
+static int is_root_ceph_dentry(struct inode *inode, struct dentry *dentry)
+{
+	return ceph_ino(inode) == CEPH_INO_ROOT &&
+		strncmp(dentry->d_name.name, ".ceph", 5) == 0;
+}
+
+/*
+ * Look up a single dir entry.  If there is a lookup intent, inform
+ * the MDS so that it gets our 'caps wanted' value in a single op.
+ */
+static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
+				  unsigned int flags)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	int op;
+	int err;
+
+	dout("lookup %p dentry %p '%pd'\n",
+	     dir, dentry, dentry);
+
+	if (dentry->d_name.len > NAME_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	err = ceph_init_dentry(dentry);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	/* can we conclude ENOENT locally? */
+	if (d_really_is_negative(dentry)) {
+		struct ceph_inode_info *ci = ceph_inode(dir);
+		struct ceph_dentry_info *di = ceph_dentry(dentry);
+
+		spin_lock(&ci->i_ceph_lock);
+		dout(" dir %p flags are %d\n", dir, ci->i_ceph_flags);
+		if (strncmp(dentry->d_name.name,
+			    fsc->mount_options->snapdir_name,
+			    dentry->d_name.len) &&
+		    !is_root_ceph_dentry(dir, dentry) &&
+		    ceph_test_mount_opt(fsc, DCACHE) &&
+		    __ceph_dir_is_complete(ci) &&
+		    (__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
+			spin_unlock(&ci->i_ceph_lock);
+			dout(" dir %p complete, -ENOENT\n", dir);
+			d_add(dentry, NULL);
+			di->lease_shared_gen = ci->i_shared_gen;
+			return NULL;
+		}
+		spin_unlock(&ci->i_ceph_lock);
+	}
+
+	op = ceph_snap(dir) == CEPH_SNAPDIR ?
+		CEPH_MDS_OP_LOOKUPSNAP : CEPH_MDS_OP_LOOKUP;
+	req = ceph_mdsc_create_request(mdsc, op, USE_ANY_MDS);
+	if (IS_ERR(req))
+		return ERR_CAST(req);
+	req->r_dentry = dget(dentry);
+	req->r_num_caps = 2;
+	/* we only need inode linkage */
+	req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INODE);
+	req->r_locked_dir = dir;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	err = ceph_handle_snapdir(req, dentry, err);
+	dentry = ceph_finish_lookup(req, dentry, err);
+	ceph_mdsc_put_request(req);  /* will dput(dentry) */
+	dout("lookup result=%p\n", dentry);
+	return dentry;
+}
+
+/*
+ * If we do a create but get no trace back from the MDS, follow up with
+ * a lookup (the VFS expects us to link up the provided dentry).
+ */
+int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry)
+{
+	struct dentry *result = ceph_lookup(dir, dentry, 0);
+
+	if (result && !IS_ERR(result)) {
+		/*
+		 * We created the item, then did a lookup, and found
+		 * it was already linked to another inode we already
+		 * had in our cache (and thus got spliced). To not
+		 * confuse VFS (especially when inode is a directory),
+		 * we don't link our dentry to that inode, return an
+		 * error instead.
+		 *
+		 * This event should be rare and it happens only when
+		 * we talk to old MDS. Recent MDS does not send traceless
+		 * reply for request that creates new inode.
+		 */
+		d_drop(result);
+		return -ESTALE;
+	}
+	return PTR_ERR(result);
+}
+
+static int ceph_mknod(struct inode *dir, struct dentry *dentry,
+		      umode_t mode, dev_t rdev)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	struct ceph_acls_info acls = {};
+	int err;
+
+	if (ceph_snap(dir) != CEPH_NOSNAP)
+		return -EROFS;
+
+	err = ceph_pre_init_acls(dir, &mode, &acls);
+	if (err < 0)
+		return err;
+
+	dout("mknod in dir %p dentry %p mode 0%ho rdev %d\n",
+	     dir, dentry, mode, rdev);
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_MKNOD, USE_AUTH_MDS);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+	req->r_dentry = dget(dentry);
+	req->r_num_caps = 2;
+	req->r_locked_dir = dir;
+	req->r_args.mknod.mode = cpu_to_le32(mode);
+	req->r_args.mknod.rdev = cpu_to_le32(rdev);
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
+	if (acls.pagelist) {
+		req->r_pagelist = acls.pagelist;
+		acls.pagelist = NULL;
+	}
+	err = ceph_mdsc_do_request(mdsc, dir, req);
+	if (!err && !req->r_reply_info.head->is_dentry)
+		err = ceph_handle_notrace_create(dir, dentry);
+	ceph_mdsc_put_request(req);
+out:
+	if (!err)
+		ceph_init_inode_acls(d_inode(dentry), &acls);
+	else
+		d_drop(dentry);
+	ceph_release_acls_info(&acls);
+	return err;
+}
+
+static int ceph_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+		       bool excl)
+{
+	return ceph_mknod(dir, dentry, mode, 0);
+}
+
+static int ceph_symlink(struct inode *dir, struct dentry *dentry,
+			    const char *dest)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	int err;
+
+	if (ceph_snap(dir) != CEPH_NOSNAP)
+		return -EROFS;
+
+	dout("symlink in dir %p dentry %p to '%s'\n", dir, dentry, dest);
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SYMLINK, USE_AUTH_MDS);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+	req->r_path2 = kstrdup(dest, GFP_NOFS);
+	if (!req->r_path2) {
+		err = -ENOMEM;
+		ceph_mdsc_put_request(req);
+		goto out;
+	}
+	req->r_locked_dir = dir;
+	req->r_dentry = dget(dentry);
+	req->r_num_caps = 2;
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
+	err = ceph_mdsc_do_request(mdsc, dir, req);
+	if (!err && !req->r_reply_info.head->is_dentry)
+		err = ceph_handle_notrace_create(dir, dentry);
+	ceph_mdsc_put_request(req);
+out:
+	if (err)
+		d_drop(dentry);
+	return err;
+}
+
+static int ceph_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	struct ceph_acls_info acls = {};
+	int err = -EROFS;
+	int op;
+
+	if (ceph_snap(dir) == CEPH_SNAPDIR) {
+		/* mkdir .snap/foo is a MKSNAP */
+		op = CEPH_MDS_OP_MKSNAP;
+		dout("mksnap dir %p snap '%pd' dn %p\n", dir,
+		     dentry, dentry);
+	} else if (ceph_snap(dir) == CEPH_NOSNAP) {
+		dout("mkdir dir %p dn %p mode 0%ho\n", dir, dentry, mode);
+		op = CEPH_MDS_OP_MKDIR;
+	} else {
+		goto out;
+	}
+
+	mode |= S_IFDIR;
+	err = ceph_pre_init_acls(dir, &mode, &acls);
+	if (err < 0)
+		goto out;
+
+	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+
+	req->r_dentry = dget(dentry);
+	req->r_num_caps = 2;
+	req->r_locked_dir = dir;
+	req->r_args.mkdir.mode = cpu_to_le32(mode);
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
+	if (acls.pagelist) {
+		req->r_pagelist = acls.pagelist;
+		acls.pagelist = NULL;
+	}
+	err = ceph_mdsc_do_request(mdsc, dir, req);
+	if (!err &&
+	    !req->r_reply_info.head->is_target &&
+	    !req->r_reply_info.head->is_dentry)
+		err = ceph_handle_notrace_create(dir, dentry);
+	ceph_mdsc_put_request(req);
+out:
+	if (!err)
+		ceph_init_inode_acls(d_inode(dentry), &acls);
+	else
+		d_drop(dentry);
+	ceph_release_acls_info(&acls);
+	return err;
+}
+
+static int ceph_link(struct dentry *old_dentry, struct inode *dir,
+		     struct dentry *dentry)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	int err;
+
+	if (ceph_snap(dir) != CEPH_NOSNAP)
+		return -EROFS;
+
+	dout("link in dir %p old_dentry %p dentry %p\n", dir,
+	     old_dentry, dentry);
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LINK, USE_AUTH_MDS);
+	if (IS_ERR(req)) {
+		d_drop(dentry);
+		return PTR_ERR(req);
+	}
+	req->r_dentry = dget(dentry);
+	req->r_num_caps = 2;
+	req->r_old_dentry = dget(old_dentry);
+	req->r_locked_dir = dir;
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
+	/* release LINK_SHARED on source inode (mds will lock it) */
+	req->r_old_inode_drop = CEPH_CAP_LINK_SHARED;
+	err = ceph_mdsc_do_request(mdsc, dir, req);
+	if (err) {
+		d_drop(dentry);
+	} else if (!req->r_reply_info.head->is_dentry) {
+		ihold(d_inode(old_dentry));
+		d_instantiate(dentry, d_inode(old_dentry));
+	}
+	ceph_mdsc_put_request(req);
+	return err;
+}
+
+/*
+ * For a soon-to-be unlinked file, drop the AUTH_RDCACHE caps.  If it
+ * looks like the link count will hit 0, drop any other caps (other
+ * than PIN) we don't specifically want (due to the file still being
+ * open).
+ */
+static int drop_caps_for_unlink(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
+
+	spin_lock(&ci->i_ceph_lock);
+	if (inode->i_nlink == 1) {
+		drop |= ~(__ceph_caps_wanted(ci) | CEPH_CAP_PIN);
+		ci->i_ceph_flags |= CEPH_I_NODELAY;
+	}
+	spin_unlock(&ci->i_ceph_lock);
+	return drop;
+}
+
+/*
+ * rmdir and unlink are differ only by the metadata op code
+ */
+static int ceph_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct inode *inode = d_inode(dentry);
+	struct ceph_mds_request *req;
+	int err = -EROFS;
+	int op;
+
+	if (ceph_snap(dir) == CEPH_SNAPDIR) {
+		/* rmdir .snap/foo is RMSNAP */
+		dout("rmsnap dir %p '%pd' dn %p\n", dir, dentry, dentry);
+		op = CEPH_MDS_OP_RMSNAP;
+	} else if (ceph_snap(dir) == CEPH_NOSNAP) {
+		dout("unlink/rmdir dir %p dn %p inode %p\n",
+		     dir, dentry, inode);
+		op = d_is_dir(dentry) ?
+			CEPH_MDS_OP_RMDIR : CEPH_MDS_OP_UNLINK;
+	} else
+		goto out;
+	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+	req->r_dentry = dget(dentry);
+	req->r_num_caps = 2;
+	req->r_locked_dir = dir;
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
+	req->r_inode_drop = drop_caps_for_unlink(inode);
+	err = ceph_mdsc_do_request(mdsc, dir, req);
+	if (!err && !req->r_reply_info.head->is_dentry)
+		d_delete(dentry);
+	ceph_mdsc_put_request(req);
+out:
+	return err;
+}
+
+static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
+		       struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(old_dir->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	int op = CEPH_MDS_OP_RENAME;
+	int err;
+
+	if (ceph_snap(old_dir) != ceph_snap(new_dir))
+		return -EXDEV;
+	if (ceph_snap(old_dir) != CEPH_NOSNAP) {
+		if (old_dir == new_dir && ceph_snap(old_dir) == CEPH_SNAPDIR)
+			op = CEPH_MDS_OP_RENAMESNAP;
+		else
+			return -EROFS;
+	}
+	dout("rename dir %p dentry %p to dir %p dentry %p\n",
+	     old_dir, old_dentry, new_dir, new_dentry);
+	req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	ihold(old_dir);
+	req->r_dentry = dget(new_dentry);
+	req->r_num_caps = 2;
+	req->r_old_dentry = dget(old_dentry);
+	req->r_old_dentry_dir = old_dir;
+	req->r_locked_dir = new_dir;
+	req->r_old_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_old_dentry_unless = CEPH_CAP_FILE_EXCL;
+	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
+	/* release LINK_RDCACHE on source inode (mds will lock it) */
+	req->r_old_inode_drop = CEPH_CAP_LINK_SHARED;
+	if (d_really_is_positive(new_dentry))
+		req->r_inode_drop = drop_caps_for_unlink(d_inode(new_dentry));
+	err = ceph_mdsc_do_request(mdsc, old_dir, req);
+	if (!err && !req->r_reply_info.head->is_dentry) {
+		/*
+		 * Normally d_move() is done by fill_trace (called by
+		 * do_request, above).  If there is no trace, we need
+		 * to do it here.
+		 */
+
+		d_move(old_dentry, new_dentry);
+
+		/* ensure target dentry is invalidated, despite
+		   rehashing bug in vfs_rename_dir */
+		ceph_invalidate_dentry_lease(new_dentry);
+
+		/* d_move screws up sibling dentries' offsets */
+		ceph_dir_clear_complete(old_dir);
+		ceph_dir_clear_complete(new_dir);
+
+	}
+	ceph_mdsc_put_request(req);
+	return err;
+}
+
+/*
+ * Ensure a dentry lease will no longer revalidate.
+ */
+void ceph_invalidate_dentry_lease(struct dentry *dentry)
+{
+	spin_lock(&dentry->d_lock);
+	dentry->d_time = jiffies;
+	ceph_dentry(dentry)->lease_shared_gen = 0;
+	spin_unlock(&dentry->d_lock);
+}
+
+/*
+ * Check if dentry lease is valid.  If not, delete the lease.  Try to
+ * renew if the least is more than half up.
+ */
+static int dentry_lease_is_valid(struct dentry *dentry)
+{
+	struct ceph_dentry_info *di;
+	struct ceph_mds_session *s;
+	int valid = 0;
+	u32 gen;
+	unsigned long ttl;
+	struct ceph_mds_session *session = NULL;
+	struct inode *dir = NULL;
+	u32 seq = 0;
+
+	spin_lock(&dentry->d_lock);
+	di = ceph_dentry(dentry);
+	if (di->lease_session) {
+		s = di->lease_session;
+		spin_lock(&s->s_gen_ttl_lock);
+		gen = s->s_cap_gen;
+		ttl = s->s_cap_ttl;
+		spin_unlock(&s->s_gen_ttl_lock);
+
+		if (di->lease_gen == gen &&
+		    time_before(jiffies, dentry->d_time) &&
+		    time_before(jiffies, ttl)) {
+			valid = 1;
+			if (di->lease_renew_after &&
+			    time_after(jiffies, di->lease_renew_after)) {
+				/* we should renew */
+				dir = d_inode(dentry->d_parent);
+				session = ceph_get_mds_session(s);
+				seq = di->lease_seq;
+				di->lease_renew_after = 0;
+				di->lease_renew_from = jiffies;
+			}
+		}
+	}
+	spin_unlock(&dentry->d_lock);
+
+	if (session) {
+		ceph_mdsc_lease_send_msg(session, dir, dentry,
+					 CEPH_MDS_LEASE_RENEW, seq);
+		ceph_put_mds_session(session);
+	}
+	dout("dentry_lease_is_valid - dentry %p = %d\n", dentry, valid);
+	return valid;
+}
+
+/*
+ * Check if directory-wide content lease/cap is valid.
+ */
+static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
+{
+	struct ceph_inode_info *ci = ceph_inode(dir);
+	struct ceph_dentry_info *di = ceph_dentry(dentry);
+	int valid = 0;
+
+	spin_lock(&ci->i_ceph_lock);
+	if (ci->i_shared_gen == di->lease_shared_gen)
+		valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
+	spin_unlock(&ci->i_ceph_lock);
+	dout("dir_lease_is_valid dir %p v%u dentry %p v%u = %d\n",
+	     dir, (unsigned)ci->i_shared_gen, dentry,
+	     (unsigned)di->lease_shared_gen, valid);
+	return valid;
+}
+
+/*
+ * Check if cached dentry can be trusted.
+ */
+static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	int valid = 0;
+	struct inode *dir;
+
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	dout("d_revalidate %p '%pd' inode %p offset %lld\n", dentry,
+	     dentry, d_inode(dentry), ceph_dentry(dentry)->offset);
+
+	dir = ceph_get_dentry_parent_inode(dentry);
+
+	/* always trust cached snapped dentries, snapdir dentry */
+	if (ceph_snap(dir) != CEPH_NOSNAP) {
+		dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry,
+		     dentry, d_inode(dentry));
+		valid = 1;
+	} else if (d_really_is_positive(dentry) &&
+		   ceph_snap(d_inode(dentry)) == CEPH_SNAPDIR) {
+		valid = 1;
+	} else if (dentry_lease_is_valid(dentry) ||
+		   dir_lease_is_valid(dir, dentry)) {
+		if (d_really_is_positive(dentry))
+			valid = ceph_is_any_caps(d_inode(dentry));
+		else
+			valid = 1;
+	}
+
+	dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");
+	if (valid) {
+		ceph_dentry_lru_touch(dentry);
+	} else {
+		ceph_dir_clear_complete(dir);
+	}
+	iput(dir);
+	return valid;
+}
+
+/*
+ * Release our ceph_dentry_info.
+ */
+static void ceph_d_release(struct dentry *dentry)
+{
+	struct ceph_dentry_info *di = ceph_dentry(dentry);
+
+	dout("d_release %p\n", dentry);
+	ceph_dentry_lru_del(dentry);
+	if (di->lease_session)
+		ceph_put_mds_session(di->lease_session);
+	kmem_cache_free(ceph_dentry_cachep, di);
+	dentry->d_fsdata = NULL;
+}
+
+static int ceph_snapdir_d_revalidate(struct dentry *dentry,
+					  unsigned int flags)
+{
+	/*
+	 * Eventually, we'll want to revalidate snapped metadata
+	 * too... probably...
+	 */
+	return 1;
+}
+
+/*
+ * When the VFS prunes a dentry from the cache, we need to clear the
+ * complete flag on the parent directory.
+ *
+ * Called under dentry->d_lock.
+ */
+static void ceph_d_prune(struct dentry *dentry)
+{
+	dout("ceph_d_prune %p\n", dentry);
+
+	/* do we have a valid parent? */
+	if (IS_ROOT(dentry))
+		return;
+
+	/* if we are not hashed, we don't affect dir's completeness */
+	if (d_unhashed(dentry))
+		return;
+
+	/*
+	 * we hold d_lock, so d_parent is stable, and d_fsdata is never
+	 * cleared until d_release
+	 */
+	ceph_dir_clear_complete(d_inode(dentry->d_parent));
+}
+
+/*
+ * read() on a dir.  This weird interface hack only works if mounted
+ * with '-o dirstat'.
+ */
+static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
+			     loff_t *ppos)
+{
+	struct ceph_file_info *cf = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int left;
+	const int bufsize = 1024;
+
+	if (!ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb), DIRSTAT))
+		return -EISDIR;
+
+	if (!cf->dir_info) {
+		cf->dir_info = kmalloc(bufsize, GFP_NOFS);
+		if (!cf->dir_info)
+			return -ENOMEM;
+		cf->dir_info_len =
+			snprintf(cf->dir_info, bufsize,
+				"entries:   %20lld\n"
+				" files:    %20lld\n"
+				" subdirs:  %20lld\n"
+				"rentries:  %20lld\n"
+				" rfiles:   %20lld\n"
+				" rsubdirs: %20lld\n"
+				"rbytes:    %20lld\n"
+				"rctime:    %10ld.%09ld\n",
+				ci->i_files + ci->i_subdirs,
+				ci->i_files,
+				ci->i_subdirs,
+				ci->i_rfiles + ci->i_rsubdirs,
+				ci->i_rfiles,
+				ci->i_rsubdirs,
+				ci->i_rbytes,
+				(long)ci->i_rctime.tv_sec,
+				(long)ci->i_rctime.tv_nsec);
+	}
+
+	if (*ppos >= cf->dir_info_len)
+		return 0;
+	size = min_t(unsigned, size, cf->dir_info_len-*ppos);
+	left = copy_to_user(buf, cf->dir_info + *ppos, size);
+	if (left == size)
+		return -EFAULT;
+	*ppos += (size - left);
+	return size - left;
+}
+
+/*
+ * an fsync() on a dir will wait for any uncommitted directory
+ * operations to commit.
+ */
+static int ceph_dir_fsync(struct file *file, loff_t start, loff_t end,
+			  int datasync)
+{
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct list_head *head = &ci->i_unsafe_dirops;
+	struct ceph_mds_request *req;
+	u64 last_tid;
+	int ret = 0;
+
+	dout("dir_fsync %p\n", inode);
+	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (ret)
+		return ret;
+	mutex_lock(&inode->i_mutex);
+
+	spin_lock(&ci->i_unsafe_lock);
+	if (list_empty(head))
+		goto out;
+
+	req = list_entry(head->prev,
+			 struct ceph_mds_request, r_unsafe_dir_item);
+	last_tid = req->r_tid;
+
+	do {
+		ceph_mdsc_get_request(req);
+		spin_unlock(&ci->i_unsafe_lock);
+
+		dout("dir_fsync %p wait on tid %llu (until %llu)\n",
+		     inode, req->r_tid, last_tid);
+		if (req->r_timeout) {
+			unsigned long time_left = wait_for_completion_timeout(
+							&req->r_safe_completion,
+							req->r_timeout);
+			if (time_left > 0)
+				ret = 0;
+			else
+				ret = -EIO;  /* timed out */
+		} else {
+			wait_for_completion(&req->r_safe_completion);
+		}
+		ceph_mdsc_put_request(req);
+
+		spin_lock(&ci->i_unsafe_lock);
+		if (ret || list_empty(head))
+			break;
+		req = list_entry(head->next,
+				 struct ceph_mds_request, r_unsafe_dir_item);
+	} while (req->r_tid < last_tid);
+out:
+	spin_unlock(&ci->i_unsafe_lock);
+	mutex_unlock(&inode->i_mutex);
+
+	return ret;
+}
+
+/*
+ * We maintain a private dentry LRU.
+ *
+ * FIXME: this needs to be changed to a per-mds lru to be useful.
+ */
+void ceph_dentry_lru_add(struct dentry *dn)
+{
+	struct ceph_dentry_info *di = ceph_dentry(dn);
+	struct ceph_mds_client *mdsc;
+
+	dout("dentry_lru_add %p %p '%pd'\n", di, dn, dn);
+	mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
+	spin_lock(&mdsc->dentry_lru_lock);
+	list_add_tail(&di->lru, &mdsc->dentry_lru);
+	mdsc->num_dentry++;
+	spin_unlock(&mdsc->dentry_lru_lock);
+}
+
+void ceph_dentry_lru_touch(struct dentry *dn)
+{
+	struct ceph_dentry_info *di = ceph_dentry(dn);
+	struct ceph_mds_client *mdsc;
+
+	dout("dentry_lru_touch %p %p '%pd' (offset %lld)\n", di, dn, dn,
+	     di->offset);
+	mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
+	spin_lock(&mdsc->dentry_lru_lock);
+	list_move_tail(&di->lru, &mdsc->dentry_lru);
+	spin_unlock(&mdsc->dentry_lru_lock);
+}
+
+void ceph_dentry_lru_del(struct dentry *dn)
+{
+	struct ceph_dentry_info *di = ceph_dentry(dn);
+	struct ceph_mds_client *mdsc;
+
+	dout("dentry_lru_del %p %p '%pd'\n", di, dn, dn);
+	mdsc = ceph_sb_to_client(dn->d_sb)->mdsc;
+	spin_lock(&mdsc->dentry_lru_lock);
+	list_del_init(&di->lru);
+	mdsc->num_dentry--;
+	spin_unlock(&mdsc->dentry_lru_lock);
+}
+
+/*
+ * Return name hash for a given dentry.  This is dependent on
+ * the parent directory's hash function.
+ */
+unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
+{
+	struct ceph_inode_info *dci = ceph_inode(dir);
+
+	switch (dci->i_dir_layout.dl_dir_hash) {
+	case 0:	/* for backward compat */
+	case CEPH_STR_HASH_LINUX:
+		return dn->d_name.hash;
+
+	default:
+		return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
+				     dn->d_name.name, dn->d_name.len);
+	}
+}
+
+const struct file_operations ceph_dir_fops = {
+	.read = ceph_read_dir,
+	.iterate = ceph_readdir,
+	.llseek = ceph_dir_llseek,
+	.open = ceph_open,
+	.release = ceph_release,
+	.unlocked_ioctl = ceph_ioctl,
+	.fsync = ceph_dir_fsync,
+};
+
+const struct file_operations ceph_snapdir_fops = {
+	.iterate = ceph_readdir,
+	.llseek = ceph_dir_llseek,
+	.open = ceph_open,
+	.release = ceph_release,
+};
+
+const struct inode_operations ceph_dir_iops = {
+	.lookup = ceph_lookup,
+	.permission = ceph_permission,
+	.getattr = ceph_getattr,
+	.setattr = ceph_setattr,
+	.setxattr = ceph_setxattr,
+	.getxattr = ceph_getxattr,
+	.listxattr = ceph_listxattr,
+	.removexattr = ceph_removexattr,
+	.get_acl = ceph_get_acl,
+	.set_acl = ceph_set_acl,
+	.mknod = ceph_mknod,
+	.symlink = ceph_symlink,
+	.mkdir = ceph_mkdir,
+	.link = ceph_link,
+	.unlink = ceph_unlink,
+	.rmdir = ceph_unlink,
+	.rename = ceph_rename,
+	.create = ceph_create,
+	.atomic_open = ceph_atomic_open,
+};
+
+const struct inode_operations ceph_snapdir_iops = {
+	.lookup = ceph_lookup,
+	.permission = ceph_permission,
+	.getattr = ceph_getattr,
+	.mkdir = ceph_mkdir,
+	.rmdir = ceph_unlink,
+	.rename = ceph_rename,
+};
+
+const struct dentry_operations ceph_dentry_ops = {
+	.d_revalidate = ceph_d_revalidate,
+	.d_release = ceph_d_release,
+	.d_prune = ceph_d_prune,
+};
+
+const struct dentry_operations ceph_snapdir_dentry_ops = {
+	.d_revalidate = ceph_snapdir_d_revalidate,
+	.d_release = ceph_d_release,
+};
+
+const struct dentry_operations ceph_snap_dentry_ops = {
+	.d_release = ceph_d_release,
+	.d_prune = ceph_d_prune,
+};
diff --git a/fs/ceph/export.c b/fs/ceph/export.c
new file mode 100644
index 000000000..fe02ae7f0
--- /dev/null
+++ b/fs/ceph/export.c
@@ -0,0 +1,250 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/exportfs.h>
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+
+#include "super.h"
+#include "mds_client.h"
+
+/*
+ * Basic fh
+ */
+struct ceph_nfs_fh {
+	u64 ino;
+} __attribute__ ((packed));
+
+/*
+ * Larger fh that includes parent ino.
+ */
+struct ceph_nfs_confh {
+	u64 ino, parent_ino;
+} __attribute__ ((packed));
+
+static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
+			  struct inode *parent_inode)
+{
+	int type;
+	struct ceph_nfs_fh *fh = (void *)rawfh;
+	struct ceph_nfs_confh *cfh = (void *)rawfh;
+	int connected_handle_length = sizeof(*cfh)/4;
+	int handle_length = sizeof(*fh)/4;
+
+	/* don't re-export snaps */
+	if (ceph_snap(inode) != CEPH_NOSNAP)
+		return -EINVAL;
+
+	if (parent_inode && (*max_len < connected_handle_length)) {
+		*max_len = connected_handle_length;
+		return FILEID_INVALID;
+	} else if (*max_len < handle_length) {
+		*max_len = handle_length;
+		return FILEID_INVALID;
+	}
+
+	if (parent_inode) {
+		dout("encode_fh %llx with parent %llx\n",
+		     ceph_ino(inode), ceph_ino(parent_inode));
+		cfh->ino = ceph_ino(inode);
+		cfh->parent_ino = ceph_ino(parent_inode);
+		*max_len = connected_handle_length;
+		type = FILEID_INO32_GEN_PARENT;
+	} else {
+		dout("encode_fh %llx\n", ceph_ino(inode));
+		fh->ino = ceph_ino(inode);
+		*max_len = handle_length;
+		type = FILEID_INO32_GEN;
+	}
+	return type;
+}
+
+static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
+{
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
+	struct inode *inode;
+	struct dentry *dentry;
+	struct ceph_vino vino;
+	int err;
+
+	vino.ino = ino;
+	vino.snap = CEPH_NOSNAP;
+	inode = ceph_find_inode(sb, vino);
+	if (!inode) {
+		struct ceph_mds_request *req;
+
+		req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
+					       USE_ANY_MDS);
+		if (IS_ERR(req))
+			return ERR_CAST(req);
+
+		req->r_ino1 = vino;
+		req->r_num_caps = 1;
+		err = ceph_mdsc_do_request(mdsc, NULL, req);
+		inode = req->r_target_inode;
+		if (inode)
+			ihold(inode);
+		ceph_mdsc_put_request(req);
+		if (!inode)
+			return ERR_PTR(-ESTALE);
+	}
+
+	dentry = d_obtain_alias(inode);
+	if (IS_ERR(dentry)) {
+		iput(inode);
+		return dentry;
+	}
+	err = ceph_init_dentry(dentry);
+	if (err < 0) {
+		dput(dentry);
+		return ERR_PTR(err);
+	}
+	dout("__fh_to_dentry %llx %p dentry %p\n", ino, inode, dentry);
+	return dentry;
+}
+
+/*
+ * convert regular fh to dentry
+ */
+static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
+					struct fid *fid,
+					int fh_len, int fh_type)
+{
+	struct ceph_nfs_fh *fh = (void *)fid->raw;
+
+	if (fh_type != FILEID_INO32_GEN  &&
+	    fh_type != FILEID_INO32_GEN_PARENT)
+		return NULL;
+	if (fh_len < sizeof(*fh) / 4)
+		return NULL;
+
+	dout("fh_to_dentry %llx\n", fh->ino);
+	return __fh_to_dentry(sb, fh->ino);
+}
+
+static struct dentry *__get_parent(struct super_block *sb,
+				   struct dentry *child, u64 ino)
+{
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
+	struct ceph_mds_request *req;
+	struct inode *inode;
+	struct dentry *dentry;
+	int err;
+
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
+				       USE_ANY_MDS);
+	if (IS_ERR(req))
+		return ERR_CAST(req);
+
+	if (child) {
+		req->r_inode = d_inode(child);
+		ihold(d_inode(child));
+	} else {
+		req->r_ino1 = (struct ceph_vino) {
+			.ino = ino,
+			.snap = CEPH_NOSNAP,
+		};
+	}
+	req->r_num_caps = 1;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	inode = req->r_target_inode;
+	if (inode)
+		ihold(inode);
+	ceph_mdsc_put_request(req);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	dentry = d_obtain_alias(inode);
+	if (IS_ERR(dentry)) {
+		iput(inode);
+		return dentry;
+	}
+	err = ceph_init_dentry(dentry);
+	if (err < 0) {
+		dput(dentry);
+		return ERR_PTR(err);
+	}
+	dout("__get_parent ino %llx parent %p ino %llx.%llx\n",
+	     child ? ceph_ino(d_inode(child)) : ino,
+	     dentry, ceph_vinop(inode));
+	return dentry;
+}
+
+static struct dentry *ceph_get_parent(struct dentry *child)
+{
+	/* don't re-export snaps */
+	if (ceph_snap(d_inode(child)) != CEPH_NOSNAP)
+		return ERR_PTR(-EINVAL);
+
+	dout("get_parent %p ino %llx.%llx\n",
+	     child, ceph_vinop(d_inode(child)));
+	return __get_parent(child->d_sb, child, 0);
+}
+
+/*
+ * convert regular fh to parent
+ */
+static struct dentry *ceph_fh_to_parent(struct super_block *sb,
+					struct fid *fid,
+					int fh_len, int fh_type)
+{
+	struct ceph_nfs_confh *cfh = (void *)fid->raw;
+	struct dentry *dentry;
+
+	if (fh_type != FILEID_INO32_GEN_PARENT)
+		return NULL;
+	if (fh_len < sizeof(*cfh) / 4)
+		return NULL;
+
+	dout("fh_to_parent %llx\n", cfh->parent_ino);
+	dentry = __get_parent(sb, NULL, cfh->ino);
+	if (IS_ERR(dentry) && PTR_ERR(dentry) == -ENOENT)
+		dentry = __fh_to_dentry(sb, cfh->parent_ino);
+	return dentry;
+}
+
+static int ceph_get_name(struct dentry *parent, char *name,
+			 struct dentry *child)
+{
+	struct ceph_mds_client *mdsc;
+	struct ceph_mds_request *req;
+	int err;
+
+	mdsc = ceph_inode_to_client(d_inode(child))->mdsc;
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
+				       USE_ANY_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	mutex_lock(&d_inode(parent)->i_mutex);
+
+	req->r_inode = d_inode(child);
+	ihold(d_inode(child));
+	req->r_ino2 = ceph_vino(d_inode(parent));
+	req->r_locked_dir = d_inode(parent);
+	req->r_num_caps = 2;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+
+	mutex_unlock(&d_inode(parent)->i_mutex);
+
+	if (!err) {
+		struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
+		memcpy(name, rinfo->dname, rinfo->dname_len);
+		name[rinfo->dname_len] = 0;
+		dout("get_name %p ino %llx.%llx name %s\n",
+		     child, ceph_vinop(d_inode(child)), name);
+	} else {
+		dout("get_name %p ino %llx.%llx err %d\n",
+		     child, ceph_vinop(d_inode(child)), err);
+	}
+
+	ceph_mdsc_put_request(req);
+	return err;
+}
+
+const struct export_operations ceph_export_ops = {
+	.encode_fh = ceph_encode_fh,
+	.fh_to_dentry = ceph_fh_to_dentry,
+	.fh_to_parent = ceph_fh_to_parent,
+	.get_parent = ceph_get_parent,
+	.get_name = ceph_get_name,
+};
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
new file mode 100644
index 000000000..3b6b522b4
--- /dev/null
+++ b/fs/ceph/file.c
@@ -0,0 +1,1344 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/writeback.h>
+#include <linux/falloc.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include "cache.h"
+
+/*
+ * Ceph file operations
+ *
+ * Implement basic open/close functionality, and implement
+ * read/write.
+ *
+ * We implement three modes of file I/O:
+ *  - buffered uses the generic_file_aio_{read,write} helpers
+ *
+ *  - synchronous is used when there is multi-client read/write
+ *    sharing, avoids the page cache, and synchronously waits for an
+ *    ack from the OSD.
+ *
+ *  - direct io takes the variant of the sync path that references
+ *    user pages directly.
+ *
+ * fsync() flushes and waits on dirty pages, but just queues metadata
+ * for writeback: since the MDS can recover size and mtime there is no
+ * need to wait for MDS acknowledgement.
+ */
+
+
+/*
+ * Prepare an open request.  Preallocate ceph_cap to avoid an
+ * inopportune ENOMEM later.
+ */
+static struct ceph_mds_request *
+prepare_open_request(struct super_block *sb, int flags, int create_mode)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	int want_auth = USE_ANY_MDS;
+	int op = (flags & O_CREAT) ? CEPH_MDS_OP_CREATE : CEPH_MDS_OP_OPEN;
+
+	if (flags & (O_WRONLY|O_RDWR|O_CREAT|O_TRUNC))
+		want_auth = USE_AUTH_MDS;
+
+	req = ceph_mdsc_create_request(mdsc, op, want_auth);
+	if (IS_ERR(req))
+		goto out;
+	req->r_fmode = ceph_flags_to_mode(flags);
+	req->r_args.open.flags = cpu_to_le32(flags);
+	req->r_args.open.mode = cpu_to_le32(create_mode);
+out:
+	return req;
+}
+
+/*
+ * initialize private struct file data.
+ * if we fail, clean up by dropping fmode reference on the ceph_inode
+ */
+static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
+{
+	struct ceph_file_info *cf;
+	int ret = 0;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFREG:
+		/* First file open request creates the cookie, we want to keep
+		 * this cookie around for the filetime of the inode as not to
+		 * have to worry about fscache register / revoke / operation
+		 * races.
+		 *
+		 * Also, if we know the operation is going to invalidate data
+		 * (non readonly) just nuke the cache right away.
+		 */
+		ceph_fscache_register_inode_cookie(mdsc->fsc, ci);
+		if ((fmode & CEPH_FILE_MODE_WR))
+			ceph_fscache_invalidate(inode);
+	case S_IFDIR:
+		dout("init_file %p %p 0%o (regular)\n", inode, file,
+		     inode->i_mode);
+		cf = kmem_cache_alloc(ceph_file_cachep, GFP_NOFS | __GFP_ZERO);
+		if (cf == NULL) {
+			ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
+			return -ENOMEM;
+		}
+		cf->fmode = fmode;
+		cf->next_offset = 2;
+		file->private_data = cf;
+		BUG_ON(inode->i_fop->release != ceph_release);
+		break;
+
+	case S_IFLNK:
+		dout("init_file %p %p 0%o (symlink)\n", inode, file,
+		     inode->i_mode);
+		ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
+		break;
+
+	default:
+		dout("init_file %p %p 0%o (special)\n", inode, file,
+		     inode->i_mode);
+		/*
+		 * we need to drop the open ref now, since we don't
+		 * have .release set to ceph_release.
+		 */
+		ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
+		BUG_ON(inode->i_fop->release == ceph_release);
+
+		/* call the proper open fop */
+		ret = inode->i_fop->open(inode, file);
+	}
+	return ret;
+}
+
+/*
+ * If we already have the requisite capabilities, we can satisfy
+ * the open request locally (no need to request new caps from the
+ * MDS).  We do, however, need to inform the MDS (asynchronously)
+ * if our wanted caps set expands.
+ */
+int ceph_open(struct inode *inode, struct file *file)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	struct ceph_file_info *cf = file->private_data;
+	struct inode *parent_inode = NULL;
+	int err;
+	int flags, fmode, wanted;
+
+	if (cf) {
+		dout("open file %p is already opened\n", file);
+		return 0;
+	}
+
+	/* filter out O_CREAT|O_EXCL; vfs did that already.  yuck. */
+	flags = file->f_flags & ~(O_CREAT|O_EXCL);
+	if (S_ISDIR(inode->i_mode))
+		flags = O_DIRECTORY;  /* mds likes to know */
+
+	dout("open inode %p ino %llx.%llx file %p flags %d (%d)\n", inode,
+	     ceph_vinop(inode), file, flags, file->f_flags);
+	fmode = ceph_flags_to_mode(flags);
+	wanted = ceph_caps_for_mode(fmode);
+
+	/* snapped files are read-only */
+	if (ceph_snap(inode) != CEPH_NOSNAP && (file->f_mode & FMODE_WRITE))
+		return -EROFS;
+
+	/* trivially open snapdir */
+	if (ceph_snap(inode) == CEPH_SNAPDIR) {
+		spin_lock(&ci->i_ceph_lock);
+		__ceph_get_fmode(ci, fmode);
+		spin_unlock(&ci->i_ceph_lock);
+		return ceph_init_file(inode, file, fmode);
+	}
+
+	/*
+	 * No need to block if we have caps on the auth MDS (for
+	 * write) or any MDS (for read).  Update wanted set
+	 * asynchronously.
+	 */
+	spin_lock(&ci->i_ceph_lock);
+	if (__ceph_is_any_real_caps(ci) &&
+	    (((fmode & CEPH_FILE_MODE_WR) == 0) || ci->i_auth_cap)) {
+		int mds_wanted = __ceph_caps_mds_wanted(ci);
+		int issued = __ceph_caps_issued(ci, NULL);
+
+		dout("open %p fmode %d want %s issued %s using existing\n",
+		     inode, fmode, ceph_cap_string(wanted),
+		     ceph_cap_string(issued));
+		__ceph_get_fmode(ci, fmode);
+		spin_unlock(&ci->i_ceph_lock);
+
+		/* adjust wanted? */
+		if ((issued & wanted) != wanted &&
+		    (mds_wanted & wanted) != wanted &&
+		    ceph_snap(inode) != CEPH_SNAPDIR)
+			ceph_check_caps(ci, 0, NULL);
+
+		return ceph_init_file(inode, file, fmode);
+	} else if (ceph_snap(inode) != CEPH_NOSNAP &&
+		   (ci->i_snap_caps & wanted) == wanted) {
+		__ceph_get_fmode(ci, fmode);
+		spin_unlock(&ci->i_ceph_lock);
+		return ceph_init_file(inode, file, fmode);
+	}
+
+	spin_unlock(&ci->i_ceph_lock);
+
+	dout("open fmode %d wants %s\n", fmode, ceph_cap_string(wanted));
+	req = prepare_open_request(inode->i_sb, flags, 0);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+	req->r_inode = inode;
+	ihold(inode);
+
+	req->r_num_caps = 1;
+	if (flags & O_CREAT)
+		parent_inode = ceph_get_dentry_parent_inode(file->f_path.dentry);
+	err = ceph_mdsc_do_request(mdsc, parent_inode, req);
+	iput(parent_inode);
+	if (!err)
+		err = ceph_init_file(inode, file, req->r_fmode);
+	ceph_mdsc_put_request(req);
+	dout("open result=%d on %llx.%llx\n", err, ceph_vinop(inode));
+out:
+	return err;
+}
+
+
+/*
+ * Do a lookup + open with a single request.  If we get a non-existent
+ * file or symlink, return 1 so the VFS can retry.
+ */
+int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
+		     struct file *file, unsigned flags, umode_t mode,
+		     int *opened)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	struct dentry *dn;
+	struct ceph_acls_info acls = {};
+	int err;
+
+	dout("atomic_open %p dentry %p '%pd' %s flags %d mode 0%o\n",
+	     dir, dentry, dentry,
+	     d_unhashed(dentry) ? "unhashed" : "hashed", flags, mode);
+
+	if (dentry->d_name.len > NAME_MAX)
+		return -ENAMETOOLONG;
+
+	err = ceph_init_dentry(dentry);
+	if (err < 0)
+		return err;
+
+	if (flags & O_CREAT) {
+		err = ceph_pre_init_acls(dir, &mode, &acls);
+		if (err < 0)
+			return err;
+	}
+
+	/* do the open */
+	req = prepare_open_request(dir->i_sb, flags, mode);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out_acl;
+	}
+	req->r_dentry = dget(dentry);
+	req->r_num_caps = 2;
+	if (flags & O_CREAT) {
+		req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
+		req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
+		if (acls.pagelist) {
+			req->r_pagelist = acls.pagelist;
+			acls.pagelist = NULL;
+		}
+	}
+	req->r_locked_dir = dir;           /* caller holds dir->i_mutex */
+	err = ceph_mdsc_do_request(mdsc,
+				   (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
+				   req);
+	err = ceph_handle_snapdir(req, dentry, err);
+	if (err)
+		goto out_req;
+
+	if (err == 0 && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
+		err = ceph_handle_notrace_create(dir, dentry);
+
+	if (d_unhashed(dentry)) {
+		dn = ceph_finish_lookup(req, dentry, err);
+		if (IS_ERR(dn))
+			err = PTR_ERR(dn);
+	} else {
+		/* we were given a hashed negative dentry */
+		dn = NULL;
+	}
+	if (err)
+		goto out_req;
+	if (dn || d_really_is_negative(dentry) || d_is_symlink(dentry)) {
+		/* make vfs retry on splice, ENOENT, or symlink */
+		dout("atomic_open finish_no_open on dn %p\n", dn);
+		err = finish_no_open(file, dn);
+	} else {
+		dout("atomic_open finish_open on dn %p\n", dn);
+		if (req->r_op == CEPH_MDS_OP_CREATE && req->r_reply_info.has_create_ino) {
+			ceph_init_inode_acls(d_inode(dentry), &acls);
+			*opened |= FILE_CREATED;
+		}
+		err = finish_open(file, dentry, ceph_open, opened);
+	}
+out_req:
+	if (!req->r_err && req->r_target_inode)
+		ceph_put_fmode(ceph_inode(req->r_target_inode), req->r_fmode);
+	ceph_mdsc_put_request(req);
+out_acl:
+	ceph_release_acls_info(&acls);
+	dout("atomic_open result=%d\n", err);
+	return err;
+}
+
+int ceph_release(struct inode *inode, struct file *file)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_file_info *cf = file->private_data;
+
+	dout("release inode %p file %p\n", inode, file);
+	ceph_put_fmode(ci, cf->fmode);
+	if (cf->last_readdir)
+		ceph_mdsc_put_request(cf->last_readdir);
+	kfree(cf->last_name);
+	kfree(cf->dir_info);
+	dput(cf->dentry);
+	kmem_cache_free(ceph_file_cachep, cf);
+
+	/* wake up anyone waiting for caps on this inode */
+	wake_up_all(&ci->i_cap_wq);
+	return 0;
+}
+
+enum {
+	CHECK_EOF = 1,
+	READ_INLINE = 2,
+};
+
+/*
+ * Read a range of bytes striped over one or more objects.  Iterate over
+ * objects we stripe over.  (That's not atomic, but good enough for now.)
+ *
+ * If we get a short result from the OSD, check against i_size; we need to
+ * only return a short read to the caller if we hit EOF.
+ */
+static int striped_read(struct inode *inode,
+			u64 off, u64 len,
+			struct page **pages, int num_pages,
+			int *checkeof, bool o_direct,
+			unsigned long buf_align)
+{
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	u64 pos, this_len, left;
+	int io_align, page_align;
+	int pages_left;
+	int read;
+	struct page **page_pos;
+	int ret;
+	bool hit_stripe, was_short;
+
+	/*
+	 * we may need to do multiple reads.  not atomic, unfortunately.
+	 */
+	pos = off;
+	left = len;
+	page_pos = pages;
+	pages_left = num_pages;
+	read = 0;
+	io_align = off & ~PAGE_MASK;
+
+more:
+	if (o_direct)
+		page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
+	else
+		page_align = pos & ~PAGE_MASK;
+	this_len = left;
+	ret = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),
+				  &ci->i_layout, pos, &this_len,
+				  ci->i_truncate_seq,
+				  ci->i_truncate_size,
+				  page_pos, pages_left, page_align);
+	if (ret == -ENOENT)
+		ret = 0;
+	hit_stripe = this_len < left;
+	was_short = ret >= 0 && ret < this_len;
+	dout("striped_read %llu~%llu (read %u) got %d%s%s\n", pos, left, read,
+	     ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");
+
+	if (ret >= 0) {
+		int didpages;
+		if (was_short && (pos + ret < inode->i_size)) {
+			int zlen = min(this_len - ret,
+				       inode->i_size - pos - ret);
+			int zoff = (o_direct ? buf_align : io_align) +
+				    read + ret;
+			dout(" zero gap %llu to %llu\n",
+				pos + ret, pos + ret + zlen);
+			ceph_zero_page_vector_range(zoff, zlen, pages);
+			ret += zlen;
+		}
+
+		didpages = (page_align + ret) >> PAGE_CACHE_SHIFT;
+		pos += ret;
+		read = pos - off;
+		left -= ret;
+		page_pos += didpages;
+		pages_left -= didpages;
+
+		/* hit stripe and need continue*/
+		if (left && hit_stripe && pos < inode->i_size)
+			goto more;
+	}
+
+	if (read > 0) {
+		ret = read;
+		/* did we bounce off eof? */
+		if (pos + left > inode->i_size)
+			*checkeof = CHECK_EOF;
+	}
+
+	dout("striped_read returns %d\n", ret);
+	return ret;
+}
+
+/*
+ * Completely synchronous read and write methods.  Direct from __user
+ * buffer to osd, or directly to user pages (if O_DIRECT).
+ *
+ * If the read spans object boundary, just do multiple reads.
+ */
+static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i,
+				int *checkeof)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
+	struct page **pages;
+	u64 off = iocb->ki_pos;
+	int num_pages, ret;
+	size_t len = iov_iter_count(i);
+
+	dout("sync_read on file %p %llu~%u %s\n", file, off,
+	     (unsigned)len,
+	     (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
+
+	if (!len)
+		return 0;
+	/*
+	 * flush any page cache pages in this range.  this
+	 * will make concurrent normal and sync io slow,
+	 * but it will at least behave sensibly when they are
+	 * in sequence.
+	 */
+	ret = filemap_write_and_wait_range(inode->i_mapping, off,
+						off + len);
+	if (ret < 0)
+		return ret;
+
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		while (iov_iter_count(i)) {
+			size_t start;
+			ssize_t n;
+
+			n = iov_iter_get_pages_alloc(i, &pages, INT_MAX, &start);
+			if (n < 0)
+				return n;
+
+			num_pages = (n + start + PAGE_SIZE - 1) / PAGE_SIZE;
+
+			ret = striped_read(inode, off, n,
+					   pages, num_pages, checkeof,
+					   1, start);
+
+			ceph_put_page_vector(pages, num_pages, true);
+
+			if (ret <= 0)
+				break;
+			off += ret;
+			iov_iter_advance(i, ret);
+			if (ret < n)
+				break;
+		}
+	} else {
+		num_pages = calc_pages_for(off, len);
+		pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
+		if (IS_ERR(pages))
+			return PTR_ERR(pages);
+		ret = striped_read(inode, off, len, pages,
+					num_pages, checkeof, 0, 0);
+		if (ret > 0) {
+			int l, k = 0;
+			size_t left = ret;
+
+			while (left) {
+				size_t page_off = off & ~PAGE_MASK;
+				size_t copy = min_t(size_t,
+						    PAGE_SIZE - page_off, left);
+				l = copy_page_to_iter(pages[k++], page_off,
+						      copy, i);
+				off += l;
+				left -= l;
+				if (l < copy)
+					break;
+			}
+		}
+		ceph_release_page_vector(pages, num_pages);
+	}
+
+	if (off > iocb->ki_pos) {
+		ret = off - iocb->ki_pos;
+		iocb->ki_pos = off;
+	}
+
+	dout("sync_read result %d\n", ret);
+	return ret;
+}
+
+/*
+ * Write commit request unsafe callback, called to tell us when a
+ * request is unsafe (that is, in flight--has been handed to the
+ * messenger to send to its target osd).  It is called again when
+ * we've received a response message indicating the request is
+ * "safe" (its CEPH_OSD_FLAG_ONDISK flag is set), or when a request
+ * is completed early (and unsuccessfully) due to a timeout or
+ * interrupt.
+ *
+ * This is used if we requested both an ACK and ONDISK commit reply
+ * from the OSD.
+ */
+static void ceph_sync_write_unsafe(struct ceph_osd_request *req, bool unsafe)
+{
+	struct ceph_inode_info *ci = ceph_inode(req->r_inode);
+
+	dout("%s %p tid %llu %ssafe\n", __func__, req, req->r_tid,
+		unsafe ? "un" : "");
+	if (unsafe) {
+		ceph_get_cap_refs(ci, CEPH_CAP_FILE_WR);
+		spin_lock(&ci->i_unsafe_lock);
+		list_add_tail(&req->r_unsafe_item,
+			      &ci->i_unsafe_writes);
+		spin_unlock(&ci->i_unsafe_lock);
+	} else {
+		spin_lock(&ci->i_unsafe_lock);
+		list_del_init(&req->r_unsafe_item);
+		spin_unlock(&ci->i_unsafe_lock);
+		ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
+	}
+}
+
+
+/*
+ * Synchronous write, straight from __user pointer or user pages.
+ *
+ * If write spans object boundary, just do multiple writes.  (For a
+ * correct atomic write, we should e.g. take write locks on all
+ * objects, rollback on failure, etc.)
+ */
+static ssize_t
+ceph_sync_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_snap_context *snapc;
+	struct ceph_vino vino;
+	struct ceph_osd_request *req;
+	struct page **pages;
+	int num_pages;
+	int written = 0;
+	int flags;
+	int check_caps = 0;
+	int ret;
+	struct timespec mtime = CURRENT_TIME;
+	size_t count = iov_iter_count(from);
+
+	if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
+		return -EROFS;
+
+	dout("sync_direct_write on file %p %lld~%u\n", file, pos,
+	     (unsigned)count);
+
+	ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + count);
+	if (ret < 0)
+		return ret;
+
+	ret = invalidate_inode_pages2_range(inode->i_mapping,
+					    pos >> PAGE_CACHE_SHIFT,
+					    (pos + count) >> PAGE_CACHE_SHIFT);
+	if (ret < 0)
+		dout("invalidate_inode_pages2_range returned %d\n", ret);
+
+	flags = CEPH_OSD_FLAG_ORDERSNAP |
+		CEPH_OSD_FLAG_ONDISK |
+		CEPH_OSD_FLAG_WRITE;
+
+	while (iov_iter_count(from) > 0) {
+		u64 len = iov_iter_single_seg_count(from);
+		size_t start;
+		ssize_t n;
+
+		snapc = ci->i_snap_realm->cached_context;
+		vino = ceph_vino(inode);
+		req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
+					    vino, pos, &len, 0,
+					    2,/*include a 'startsync' command*/
+					    CEPH_OSD_OP_WRITE, flags, snapc,
+					    ci->i_truncate_seq,
+					    ci->i_truncate_size,
+					    false);
+		if (IS_ERR(req)) {
+			ret = PTR_ERR(req);
+			break;
+		}
+
+		osd_req_op_init(req, 1, CEPH_OSD_OP_STARTSYNC);
+
+		n = iov_iter_get_pages_alloc(from, &pages, len, &start);
+		if (unlikely(n < 0)) {
+			ret = n;
+			ceph_osdc_put_request(req);
+			break;
+		}
+
+		num_pages = (n + start + PAGE_SIZE - 1) / PAGE_SIZE;
+		/*
+		 * throw out any page cache pages in this range. this
+		 * may block.
+		 */
+		truncate_inode_pages_range(inode->i_mapping, pos,
+				   (pos+n) | (PAGE_CACHE_SIZE-1));
+		osd_req_op_extent_osd_data_pages(req, 0, pages, n, start,
+						false, false);
+
+		/* BUG_ON(vino.snap != CEPH_NOSNAP); */
+		ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
+
+		ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
+		if (!ret)
+			ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
+
+		ceph_put_page_vector(pages, num_pages, false);
+
+		ceph_osdc_put_request(req);
+		if (ret)
+			break;
+		pos += n;
+		written += n;
+		iov_iter_advance(from, n);
+
+		if (pos > i_size_read(inode)) {
+			check_caps = ceph_inode_set_size(inode, pos);
+			if (check_caps)
+				ceph_check_caps(ceph_inode(inode),
+						CHECK_CAPS_AUTHONLY,
+						NULL);
+		}
+	}
+
+	if (ret != -EOLDSNAPC && written > 0) {
+		iocb->ki_pos = pos;
+		ret = written;
+	}
+	return ret;
+}
+
+
+/*
+ * Synchronous write, straight from __user pointer or user pages.
+ *
+ * If write spans object boundary, just do multiple writes.  (For a
+ * correct atomic write, we should e.g. take write locks on all
+ * objects, rollback on failure, etc.)
+ */
+static ssize_t
+ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_snap_context *snapc;
+	struct ceph_vino vino;
+	struct ceph_osd_request *req;
+	struct page **pages;
+	u64 len;
+	int num_pages;
+	int written = 0;
+	int flags;
+	int check_caps = 0;
+	int ret;
+	struct timespec mtime = CURRENT_TIME;
+	size_t count = iov_iter_count(from);
+
+	if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
+		return -EROFS;
+
+	dout("sync_write on file %p %lld~%u\n", file, pos, (unsigned)count);
+
+	ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + count);
+	if (ret < 0)
+		return ret;
+
+	ret = invalidate_inode_pages2_range(inode->i_mapping,
+					    pos >> PAGE_CACHE_SHIFT,
+					    (pos + count) >> PAGE_CACHE_SHIFT);
+	if (ret < 0)
+		dout("invalidate_inode_pages2_range returned %d\n", ret);
+
+	flags = CEPH_OSD_FLAG_ORDERSNAP |
+		CEPH_OSD_FLAG_ONDISK |
+		CEPH_OSD_FLAG_WRITE |
+		CEPH_OSD_FLAG_ACK;
+
+	while ((len = iov_iter_count(from)) > 0) {
+		size_t left;
+		int n;
+
+		snapc = ci->i_snap_realm->cached_context;
+		vino = ceph_vino(inode);
+		req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
+					    vino, pos, &len, 0, 1,
+					    CEPH_OSD_OP_WRITE, flags, snapc,
+					    ci->i_truncate_seq,
+					    ci->i_truncate_size,
+					    false);
+		if (IS_ERR(req)) {
+			ret = PTR_ERR(req);
+			break;
+		}
+
+		/*
+		 * write from beginning of first page,
+		 * regardless of io alignment
+		 */
+		num_pages = (len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+
+		pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
+		if (IS_ERR(pages)) {
+			ret = PTR_ERR(pages);
+			goto out;
+		}
+
+		left = len;
+		for (n = 0; n < num_pages; n++) {
+			size_t plen = min_t(size_t, left, PAGE_SIZE);
+			ret = copy_page_from_iter(pages[n], 0, plen, from);
+			if (ret != plen) {
+				ret = -EFAULT;
+				break;
+			}
+			left -= ret;
+		}
+
+		if (ret < 0) {
+			ceph_release_page_vector(pages, num_pages);
+			goto out;
+		}
+
+		/* get a second commit callback */
+		req->r_unsafe_callback = ceph_sync_write_unsafe;
+		req->r_inode = inode;
+
+		osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
+						false, true);
+
+		/* BUG_ON(vino.snap != CEPH_NOSNAP); */
+		ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
+
+		ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
+		if (!ret)
+			ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
+
+out:
+		ceph_osdc_put_request(req);
+		if (ret == 0) {
+			pos += len;
+			written += len;
+
+			if (pos > i_size_read(inode)) {
+				check_caps = ceph_inode_set_size(inode, pos);
+				if (check_caps)
+					ceph_check_caps(ceph_inode(inode),
+							CHECK_CAPS_AUTHONLY,
+							NULL);
+			}
+		} else
+			break;
+	}
+
+	if (ret != -EOLDSNAPC && written > 0) {
+		ret = written;
+		iocb->ki_pos = pos;
+	}
+	return ret;
+}
+
+/*
+ * Wrap generic_file_aio_read with checks for cap bits on the inode.
+ * Atomically grab references, so that those bits are not released
+ * back to the MDS mid-read.
+ *
+ * Hmm, the sync read case isn't actually async... should it be?
+ */
+static ssize_t ceph_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *filp = iocb->ki_filp;
+	struct ceph_file_info *fi = filp->private_data;
+	size_t len = iov_iter_count(to);
+	struct inode *inode = file_inode(filp);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct page *pinned_page = NULL;
+	ssize_t ret;
+	int want, got = 0;
+	int retry_op = 0, read = 0;
+
+again:
+	dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
+	     inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len, inode);
+
+	if (fi->fmode & CEPH_FILE_MODE_LAZY)
+		want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
+	else
+		want = CEPH_CAP_FILE_CACHE;
+	ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, -1, &got, &pinned_page);
+	if (ret < 0)
+		return ret;
+
+	if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
+	    (iocb->ki_flags & IOCB_DIRECT) ||
+	    (fi->flags & CEPH_F_SYNC)) {
+
+		dout("aio_sync_read %p %llx.%llx %llu~%u got cap refs on %s\n",
+		     inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len,
+		     ceph_cap_string(got));
+
+		if (ci->i_inline_version == CEPH_INLINE_NONE) {
+			/* hmm, this isn't really async... */
+			ret = ceph_sync_read(iocb, to, &retry_op);
+		} else {
+			retry_op = READ_INLINE;
+		}
+	} else {
+		dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
+		     inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len,
+		     ceph_cap_string(got));
+
+		ret = generic_file_read_iter(iocb, to);
+	}
+	dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
+	     inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
+	if (pinned_page) {
+		page_cache_release(pinned_page);
+		pinned_page = NULL;
+	}
+	ceph_put_cap_refs(ci, got);
+	if (retry_op && ret >= 0) {
+		int statret;
+		struct page *page = NULL;
+		loff_t i_size;
+		if (retry_op == READ_INLINE) {
+			page = __page_cache_alloc(GFP_NOFS);
+			if (!page)
+				return -ENOMEM;
+		}
+
+		statret = __ceph_do_getattr(inode, page,
+					    CEPH_STAT_CAP_INLINE_DATA, !!page);
+		if (statret < 0) {
+			 __free_page(page);
+			if (statret == -ENODATA) {
+				BUG_ON(retry_op != READ_INLINE);
+				goto again;
+			}
+			return statret;
+		}
+
+		i_size = i_size_read(inode);
+		if (retry_op == READ_INLINE) {
+			BUG_ON(ret > 0 || read > 0);
+			if (iocb->ki_pos < i_size &&
+			    iocb->ki_pos < PAGE_CACHE_SIZE) {
+				loff_t end = min_t(loff_t, i_size,
+						   iocb->ki_pos + len);
+				end = min_t(loff_t, end, PAGE_CACHE_SIZE);
+				if (statret < end)
+					zero_user_segment(page, statret, end);
+				ret = copy_page_to_iter(page,
+						iocb->ki_pos & ~PAGE_MASK,
+						end - iocb->ki_pos, to);
+				iocb->ki_pos += ret;
+				read += ret;
+			}
+			if (iocb->ki_pos < i_size && read < len) {
+				size_t zlen = min_t(size_t, len - read,
+						    i_size - iocb->ki_pos);
+				ret = iov_iter_zero(zlen, to);
+				iocb->ki_pos += ret;
+				read += ret;
+			}
+			__free_pages(page, 0);
+			return read;
+		}
+
+		/* hit EOF or hole? */
+		if (retry_op == CHECK_EOF && iocb->ki_pos < i_size &&
+		    ret < len) {
+			dout("sync_read hit hole, ppos %lld < size %lld"
+			     ", reading more\n", iocb->ki_pos,
+			     inode->i_size);
+
+			read += ret;
+			len -= ret;
+			retry_op = 0;
+			goto again;
+		}
+	}
+
+	if (ret >= 0)
+		ret += read;
+
+	return ret;
+}
+
+/*
+ * Take cap references to avoid releasing caps to MDS mid-write.
+ *
+ * If we are synchronous, and write with an old snap context, the OSD
+ * may return EOLDSNAPC.  In that case, retry the write.. _after_
+ * dropping our cap refs and allowing the pending snap to logically
+ * complete _before_ this write occurs.
+ *
+ * If we are near ENOSPC, write synchronously.
+ */
+static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct ceph_file_info *fi = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_osd_client *osdc =
+		&ceph_sb_to_client(inode->i_sb)->client->osdc;
+	ssize_t count, written = 0;
+	int err, want, got;
+	loff_t pos;
+
+	if (ceph_snap(inode) != CEPH_NOSNAP)
+		return -EROFS;
+
+	mutex_lock(&inode->i_mutex);
+
+	/* We can write back this queue in page reclaim */
+	current->backing_dev_info = inode_to_bdi(inode);
+
+	err = generic_write_checks(iocb, from);
+	if (err <= 0)
+		goto out;
+
+	pos = iocb->ki_pos;
+	count = iov_iter_count(from);
+	err = file_remove_suid(file);
+	if (err)
+		goto out;
+
+	err = file_update_time(file);
+	if (err)
+		goto out;
+
+	if (ci->i_inline_version != CEPH_INLINE_NONE) {
+		err = ceph_uninline_data(file, NULL);
+		if (err < 0)
+			goto out;
+	}
+
+retry_snap:
+	if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) {
+		err = -ENOSPC;
+		goto out;
+	}
+
+	dout("aio_write %p %llx.%llx %llu~%zd getting caps. i_size %llu\n",
+	     inode, ceph_vinop(inode), pos, count, inode->i_size);
+	if (fi->fmode & CEPH_FILE_MODE_LAZY)
+		want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
+	else
+		want = CEPH_CAP_FILE_BUFFER;
+	got = 0;
+	err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, pos + count,
+			    &got, NULL);
+	if (err < 0)
+		goto out;
+
+	dout("aio_write %p %llx.%llx %llu~%zd got cap refs on %s\n",
+	     inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
+
+	if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
+	    (iocb->ki_flags & IOCB_DIRECT) || (fi->flags & CEPH_F_SYNC)) {
+		struct iov_iter data;
+		mutex_unlock(&inode->i_mutex);
+		/* we might need to revert back to that point */
+		data = *from;
+		if (iocb->ki_flags & IOCB_DIRECT)
+			written = ceph_sync_direct_write(iocb, &data, pos);
+		else
+			written = ceph_sync_write(iocb, &data, pos);
+		if (written == -EOLDSNAPC) {
+			dout("aio_write %p %llx.%llx %llu~%u"
+				"got EOLDSNAPC, retrying\n",
+				inode, ceph_vinop(inode),
+				pos, (unsigned)count);
+			mutex_lock(&inode->i_mutex);
+			goto retry_snap;
+		}
+		if (written > 0)
+			iov_iter_advance(from, written);
+	} else {
+		loff_t old_size = inode->i_size;
+		/*
+		 * No need to acquire the i_truncate_mutex. Because
+		 * the MDS revokes Fwb caps before sending truncate
+		 * message to us. We can't get Fwb cap while there
+		 * are pending vmtruncate. So write and vmtruncate
+		 * can not run at the same time
+		 */
+		written = generic_perform_write(file, from, pos);
+		if (likely(written >= 0))
+			iocb->ki_pos = pos + written;
+		if (inode->i_size > old_size)
+			ceph_fscache_update_objectsize(inode);
+		mutex_unlock(&inode->i_mutex);
+	}
+
+	if (written >= 0) {
+		int dirty;
+		spin_lock(&ci->i_ceph_lock);
+		ci->i_inline_version = CEPH_INLINE_NONE;
+		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
+		spin_unlock(&ci->i_ceph_lock);
+		if (dirty)
+			__mark_inode_dirty(inode, dirty);
+	}
+
+	dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
+	     inode, ceph_vinop(inode), pos, (unsigned)count,
+	     ceph_cap_string(got));
+	ceph_put_cap_refs(ci, got);
+
+	if (written >= 0 &&
+	    ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) ||
+	     ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
+		err = vfs_fsync_range(file, pos, pos + written - 1, 1);
+		if (err < 0)
+			written = err;
+	}
+
+	goto out_unlocked;
+
+out:
+	mutex_unlock(&inode->i_mutex);
+out_unlocked:
+	current->backing_dev_info = NULL;
+	return written ? written : err;
+}
+
+/*
+ * llseek.  be sure to verify file size on SEEK_END.
+ */
+static loff_t ceph_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	int ret;
+
+	mutex_lock(&inode->i_mutex);
+
+	if (whence == SEEK_END || whence == SEEK_DATA || whence == SEEK_HOLE) {
+		ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE, false);
+		if (ret < 0) {
+			offset = ret;
+			goto out;
+		}
+	}
+
+	switch (whence) {
+	case SEEK_END:
+		offset += inode->i_size;
+		break;
+	case SEEK_CUR:
+		/*
+		 * Here we special-case the lseek(fd, 0, SEEK_CUR)
+		 * position-querying operation.  Avoid rewriting the "same"
+		 * f_pos value back to the file because a concurrent read(),
+		 * write() or lseek() might have altered it
+		 */
+		if (offset == 0) {
+			offset = file->f_pos;
+			goto out;
+		}
+		offset += file->f_pos;
+		break;
+	case SEEK_DATA:
+		if (offset >= inode->i_size) {
+			ret = -ENXIO;
+			goto out;
+		}
+		break;
+	case SEEK_HOLE:
+		if (offset >= inode->i_size) {
+			ret = -ENXIO;
+			goto out;
+		}
+		offset = inode->i_size;
+		break;
+	}
+
+	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
+
+out:
+	mutex_unlock(&inode->i_mutex);
+	return offset;
+}
+
+static inline void ceph_zero_partial_page(
+	struct inode *inode, loff_t offset, unsigned size)
+{
+	struct page *page;
+	pgoff_t index = offset >> PAGE_CACHE_SHIFT;
+
+	page = find_lock_page(inode->i_mapping, index);
+	if (page) {
+		wait_on_page_writeback(page);
+		zero_user(page, offset & (PAGE_CACHE_SIZE - 1), size);
+		unlock_page(page);
+		page_cache_release(page);
+	}
+}
+
+static void ceph_zero_pagecache_range(struct inode *inode, loff_t offset,
+				      loff_t length)
+{
+	loff_t nearly = round_up(offset, PAGE_CACHE_SIZE);
+	if (offset < nearly) {
+		loff_t size = nearly - offset;
+		if (length < size)
+			size = length;
+		ceph_zero_partial_page(inode, offset, size);
+		offset += size;
+		length -= size;
+	}
+	if (length >= PAGE_CACHE_SIZE) {
+		loff_t size = round_down(length, PAGE_CACHE_SIZE);
+		truncate_pagecache_range(inode, offset, offset + size - 1);
+		offset += size;
+		length -= size;
+	}
+	if (length)
+		ceph_zero_partial_page(inode, offset, length);
+}
+
+static int ceph_zero_partial_object(struct inode *inode,
+				    loff_t offset, loff_t *length)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_osd_request *req;
+	int ret = 0;
+	loff_t zero = 0;
+	int op;
+
+	if (!length) {
+		op = offset ? CEPH_OSD_OP_DELETE : CEPH_OSD_OP_TRUNCATE;
+		length = &zero;
+	} else {
+		op = CEPH_OSD_OP_ZERO;
+	}
+
+	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
+					ceph_vino(inode),
+					offset, length,
+					0, 1, op,
+					CEPH_OSD_FLAG_WRITE |
+					CEPH_OSD_FLAG_ONDISK,
+					NULL, 0, 0, false);
+	if (IS_ERR(req)) {
+		ret = PTR_ERR(req);
+		goto out;
+	}
+
+	ceph_osdc_build_request(req, offset, NULL, ceph_vino(inode).snap,
+				&inode->i_mtime);
+
+	ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
+	if (!ret) {
+		ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
+		if (ret == -ENOENT)
+			ret = 0;
+	}
+	ceph_osdc_put_request(req);
+
+out:
+	return ret;
+}
+
+static int ceph_zero_objects(struct inode *inode, loff_t offset, loff_t length)
+{
+	int ret = 0;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	s32 stripe_unit = ceph_file_layout_su(ci->i_layout);
+	s32 stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
+	s32 object_size = ceph_file_layout_object_size(ci->i_layout);
+	u64 object_set_size = object_size * stripe_count;
+	u64 nearly, t;
+
+	/* round offset up to next period boundary */
+	nearly = offset + object_set_size - 1;
+	t = nearly;
+	nearly -= do_div(t, object_set_size);
+
+	while (length && offset < nearly) {
+		loff_t size = length;
+		ret = ceph_zero_partial_object(inode, offset, &size);
+		if (ret < 0)
+			return ret;
+		offset += size;
+		length -= size;
+	}
+	while (length >= object_set_size) {
+		int i;
+		loff_t pos = offset;
+		for (i = 0; i < stripe_count; ++i) {
+			ret = ceph_zero_partial_object(inode, pos, NULL);
+			if (ret < 0)
+				return ret;
+			pos += stripe_unit;
+		}
+		offset += object_set_size;
+		length -= object_set_size;
+	}
+	while (length) {
+		loff_t size = length;
+		ret = ceph_zero_partial_object(inode, offset, &size);
+		if (ret < 0)
+			return ret;
+		offset += size;
+		length -= size;
+	}
+	return ret;
+}
+
+static long ceph_fallocate(struct file *file, int mode,
+				loff_t offset, loff_t length)
+{
+	struct ceph_file_info *fi = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_osd_client *osdc =
+		&ceph_inode_to_client(inode)->client->osdc;
+	int want, got = 0;
+	int dirty;
+	int ret = 0;
+	loff_t endoff = 0;
+	loff_t size;
+
+	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+		return -EOPNOTSUPP;
+
+	if (!S_ISREG(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	mutex_lock(&inode->i_mutex);
+
+	if (ceph_snap(inode) != CEPH_NOSNAP) {
+		ret = -EROFS;
+		goto unlock;
+	}
+
+	if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL) &&
+		!(mode & FALLOC_FL_PUNCH_HOLE)) {
+		ret = -ENOSPC;
+		goto unlock;
+	}
+
+	if (ci->i_inline_version != CEPH_INLINE_NONE) {
+		ret = ceph_uninline_data(file, NULL);
+		if (ret < 0)
+			goto unlock;
+	}
+
+	size = i_size_read(inode);
+	if (!(mode & FALLOC_FL_KEEP_SIZE))
+		endoff = offset + length;
+
+	if (fi->fmode & CEPH_FILE_MODE_LAZY)
+		want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
+	else
+		want = CEPH_CAP_FILE_BUFFER;
+
+	ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, endoff, &got, NULL);
+	if (ret < 0)
+		goto unlock;
+
+	if (mode & FALLOC_FL_PUNCH_HOLE) {
+		if (offset < size)
+			ceph_zero_pagecache_range(inode, offset, length);
+		ret = ceph_zero_objects(inode, offset, length);
+	} else if (endoff > size) {
+		truncate_pagecache_range(inode, size, -1);
+		if (ceph_inode_set_size(inode, endoff))
+			ceph_check_caps(ceph_inode(inode),
+				CHECK_CAPS_AUTHONLY, NULL);
+	}
+
+	if (!ret) {
+		spin_lock(&ci->i_ceph_lock);
+		ci->i_inline_version = CEPH_INLINE_NONE;
+		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
+		spin_unlock(&ci->i_ceph_lock);
+		if (dirty)
+			__mark_inode_dirty(inode, dirty);
+	}
+
+	ceph_put_cap_refs(ci, got);
+unlock:
+	mutex_unlock(&inode->i_mutex);
+	return ret;
+}
+
+const struct file_operations ceph_file_fops = {
+	.open = ceph_open,
+	.release = ceph_release,
+	.llseek = ceph_llseek,
+	.read_iter = ceph_read_iter,
+	.write_iter = ceph_write_iter,
+	.mmap = ceph_mmap,
+	.fsync = ceph_fsync,
+	.lock = ceph_lock,
+	.flock = ceph_flock,
+	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
+	.unlocked_ioctl = ceph_ioctl,
+	.compat_ioctl	= ceph_ioctl,
+	.fallocate	= ceph_fallocate,
+};
+
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
new file mode 100644
index 000000000..e876e1944
--- /dev/null
+++ b/fs/ceph/inode.c
@@ -0,0 +1,2016 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/namei.h>
+#include <linux/writeback.h>
+#include <linux/vmalloc.h>
+#include <linux/posix_acl.h>
+#include <linux/random.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include "cache.h"
+#include <linux/ceph/decode.h>
+
+/*
+ * Ceph inode operations
+ *
+ * Implement basic inode helpers (get, alloc) and inode ops (getattr,
+ * setattr, etc.), xattr helpers, and helpers for assimilating
+ * metadata returned by the MDS into our cache.
+ *
+ * Also define helpers for doing asynchronous writeback, invalidation,
+ * and truncation for the benefit of those who can't afford to block
+ * (typically because they are in the message handler path).
+ */
+
+static const struct inode_operations ceph_symlink_iops;
+
+static void ceph_invalidate_work(struct work_struct *work);
+static void ceph_writeback_work(struct work_struct *work);
+static void ceph_vmtruncate_work(struct work_struct *work);
+
+/*
+ * find or create an inode, given the ceph ino number
+ */
+static int ceph_set_ino_cb(struct inode *inode, void *data)
+{
+	ceph_inode(inode)->i_vino = *(struct ceph_vino *)data;
+	inode->i_ino = ceph_vino_to_ino(*(struct ceph_vino *)data);
+	return 0;
+}
+
+struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino)
+{
+	struct inode *inode;
+	ino_t t = ceph_vino_to_ino(vino);
+
+	inode = iget5_locked(sb, t, ceph_ino_compare, ceph_set_ino_cb, &vino);
+	if (inode == NULL)
+		return ERR_PTR(-ENOMEM);
+	if (inode->i_state & I_NEW) {
+		dout("get_inode created new inode %p %llx.%llx ino %llx\n",
+		     inode, ceph_vinop(inode), (u64)inode->i_ino);
+		unlock_new_inode(inode);
+	}
+
+	dout("get_inode on %lu=%llx.%llx got %p\n", inode->i_ino, vino.ino,
+	     vino.snap, inode);
+	return inode;
+}
+
+/*
+ * get/constuct snapdir inode for a given directory
+ */
+struct inode *ceph_get_snapdir(struct inode *parent)
+{
+	struct ceph_vino vino = {
+		.ino = ceph_ino(parent),
+		.snap = CEPH_SNAPDIR,
+	};
+	struct inode *inode = ceph_get_inode(parent->i_sb, vino);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	BUG_ON(!S_ISDIR(parent->i_mode));
+	if (IS_ERR(inode))
+		return inode;
+	inode->i_mode = parent->i_mode;
+	inode->i_uid = parent->i_uid;
+	inode->i_gid = parent->i_gid;
+	inode->i_op = &ceph_snapdir_iops;
+	inode->i_fop = &ceph_snapdir_fops;
+	ci->i_snap_caps = CEPH_CAP_PIN; /* so we can open */
+	ci->i_rbytes = 0;
+	return inode;
+}
+
+const struct inode_operations ceph_file_iops = {
+	.permission = ceph_permission,
+	.setattr = ceph_setattr,
+	.getattr = ceph_getattr,
+	.setxattr = ceph_setxattr,
+	.getxattr = ceph_getxattr,
+	.listxattr = ceph_listxattr,
+	.removexattr = ceph_removexattr,
+	.get_acl = ceph_get_acl,
+	.set_acl = ceph_set_acl,
+};
+
+
+/*
+ * We use a 'frag tree' to keep track of the MDS's directory fragments
+ * for a given inode (usually there is just a single fragment).  We
+ * need to know when a child frag is delegated to a new MDS, or when
+ * it is flagged as replicated, so we can direct our requests
+ * accordingly.
+ */
+
+/*
+ * find/create a frag in the tree
+ */
+static struct ceph_inode_frag *__get_or_create_frag(struct ceph_inode_info *ci,
+						    u32 f)
+{
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+	struct ceph_inode_frag *frag;
+	int c;
+
+	p = &ci->i_fragtree.rb_node;
+	while (*p) {
+		parent = *p;
+		frag = rb_entry(parent, struct ceph_inode_frag, node);
+		c = ceph_frag_compare(f, frag->frag);
+		if (c < 0)
+			p = &(*p)->rb_left;
+		else if (c > 0)
+			p = &(*p)->rb_right;
+		else
+			return frag;
+	}
+
+	frag = kmalloc(sizeof(*frag), GFP_NOFS);
+	if (!frag) {
+		pr_err("__get_or_create_frag ENOMEM on %p %llx.%llx "
+		       "frag %x\n", &ci->vfs_inode,
+		       ceph_vinop(&ci->vfs_inode), f);
+		return ERR_PTR(-ENOMEM);
+	}
+	frag->frag = f;
+	frag->split_by = 0;
+	frag->mds = -1;
+	frag->ndist = 0;
+
+	rb_link_node(&frag->node, parent, p);
+	rb_insert_color(&frag->node, &ci->i_fragtree);
+
+	dout("get_or_create_frag added %llx.%llx frag %x\n",
+	     ceph_vinop(&ci->vfs_inode), f);
+	return frag;
+}
+
+/*
+ * find a specific frag @f
+ */
+struct ceph_inode_frag *__ceph_find_frag(struct ceph_inode_info *ci, u32 f)
+{
+	struct rb_node *n = ci->i_fragtree.rb_node;
+
+	while (n) {
+		struct ceph_inode_frag *frag =
+			rb_entry(n, struct ceph_inode_frag, node);
+		int c = ceph_frag_compare(f, frag->frag);
+		if (c < 0)
+			n = n->rb_left;
+		else if (c > 0)
+			n = n->rb_right;
+		else
+			return frag;
+	}
+	return NULL;
+}
+
+/*
+ * Choose frag containing the given value @v.  If @pfrag is
+ * specified, copy the frag delegation info to the caller if
+ * it is present.
+ */
+static u32 __ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
+			      struct ceph_inode_frag *pfrag, int *found)
+{
+	u32 t = ceph_frag_make(0, 0);
+	struct ceph_inode_frag *frag;
+	unsigned nway, i;
+	u32 n;
+
+	if (found)
+		*found = 0;
+
+	while (1) {
+		WARN_ON(!ceph_frag_contains_value(t, v));
+		frag = __ceph_find_frag(ci, t);
+		if (!frag)
+			break; /* t is a leaf */
+		if (frag->split_by == 0) {
+			if (pfrag)
+				memcpy(pfrag, frag, sizeof(*pfrag));
+			if (found)
+				*found = 1;
+			break;
+		}
+
+		/* choose child */
+		nway = 1 << frag->split_by;
+		dout("choose_frag(%x) %x splits by %d (%d ways)\n", v, t,
+		     frag->split_by, nway);
+		for (i = 0; i < nway; i++) {
+			n = ceph_frag_make_child(t, frag->split_by, i);
+			if (ceph_frag_contains_value(n, v)) {
+				t = n;
+				break;
+			}
+		}
+		BUG_ON(i == nway);
+	}
+	dout("choose_frag(%x) = %x\n", v, t);
+
+	return t;
+}
+
+u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
+		     struct ceph_inode_frag *pfrag, int *found)
+{
+	u32 ret;
+	mutex_lock(&ci->i_fragtree_mutex);
+	ret = __ceph_choose_frag(ci, v, pfrag, found);
+	mutex_unlock(&ci->i_fragtree_mutex);
+	return ret;
+}
+
+/*
+ * Process dirfrag (delegation) info from the mds.  Include leaf
+ * fragment in tree ONLY if ndist > 0.  Otherwise, only
+ * branches/splits are included in i_fragtree)
+ */
+static int ceph_fill_dirfrag(struct inode *inode,
+			     struct ceph_mds_reply_dirfrag *dirinfo)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_inode_frag *frag;
+	u32 id = le32_to_cpu(dirinfo->frag);
+	int mds = le32_to_cpu(dirinfo->auth);
+	int ndist = le32_to_cpu(dirinfo->ndist);
+	int diri_auth = -1;
+	int i;
+	int err = 0;
+
+	spin_lock(&ci->i_ceph_lock);
+	if (ci->i_auth_cap)
+		diri_auth = ci->i_auth_cap->mds;
+	spin_unlock(&ci->i_ceph_lock);
+
+	mutex_lock(&ci->i_fragtree_mutex);
+	if (ndist == 0 && mds == diri_auth) {
+		/* no delegation info needed. */
+		frag = __ceph_find_frag(ci, id);
+		if (!frag)
+			goto out;
+		if (frag->split_by == 0) {
+			/* tree leaf, remove */
+			dout("fill_dirfrag removed %llx.%llx frag %x"
+			     " (no ref)\n", ceph_vinop(inode), id);
+			rb_erase(&frag->node, &ci->i_fragtree);
+			kfree(frag);
+		} else {
+			/* tree branch, keep and clear */
+			dout("fill_dirfrag cleared %llx.%llx frag %x"
+			     " referral\n", ceph_vinop(inode), id);
+			frag->mds = -1;
+			frag->ndist = 0;
+		}
+		goto out;
+	}
+
+
+	/* find/add this frag to store mds delegation info */
+	frag = __get_or_create_frag(ci, id);
+	if (IS_ERR(frag)) {
+		/* this is not the end of the world; we can continue
+		   with bad/inaccurate delegation info */
+		pr_err("fill_dirfrag ENOMEM on mds ref %llx.%llx fg %x\n",
+		       ceph_vinop(inode), le32_to_cpu(dirinfo->frag));
+		err = -ENOMEM;
+		goto out;
+	}
+
+	frag->mds = mds;
+	frag->ndist = min_t(u32, ndist, CEPH_MAX_DIRFRAG_REP);
+	for (i = 0; i < frag->ndist; i++)
+		frag->dist[i] = le32_to_cpu(dirinfo->dist[i]);
+	dout("fill_dirfrag %llx.%llx frag %x ndist=%d\n",
+	     ceph_vinop(inode), frag->frag, frag->ndist);
+
+out:
+	mutex_unlock(&ci->i_fragtree_mutex);
+	return err;
+}
+
+static int ceph_fill_fragtree(struct inode *inode,
+			      struct ceph_frag_tree_head *fragtree,
+			      struct ceph_mds_reply_dirfrag *dirinfo)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_inode_frag *frag;
+	struct rb_node *rb_node;
+	int i;
+	u32 id, nsplits;
+	bool update = false;
+
+	mutex_lock(&ci->i_fragtree_mutex);
+	nsplits = le32_to_cpu(fragtree->nsplits);
+	if (nsplits) {
+		i = prandom_u32() % nsplits;
+		id = le32_to_cpu(fragtree->splits[i].frag);
+		if (!__ceph_find_frag(ci, id))
+			update = true;
+	} else if (!RB_EMPTY_ROOT(&ci->i_fragtree)) {
+		rb_node = rb_first(&ci->i_fragtree);
+		frag = rb_entry(rb_node, struct ceph_inode_frag, node);
+		if (frag->frag != ceph_frag_make(0, 0) || rb_next(rb_node))
+			update = true;
+	}
+	if (!update && dirinfo) {
+		id = le32_to_cpu(dirinfo->frag);
+		if (id != __ceph_choose_frag(ci, id, NULL, NULL))
+			update = true;
+	}
+	if (!update)
+		goto out_unlock;
+
+	dout("fill_fragtree %llx.%llx\n", ceph_vinop(inode));
+	rb_node = rb_first(&ci->i_fragtree);
+	for (i = 0; i < nsplits; i++) {
+		id = le32_to_cpu(fragtree->splits[i].frag);
+		frag = NULL;
+		while (rb_node) {
+			frag = rb_entry(rb_node, struct ceph_inode_frag, node);
+			if (ceph_frag_compare(frag->frag, id) >= 0) {
+				if (frag->frag != id)
+					frag = NULL;
+				else
+					rb_node = rb_next(rb_node);
+				break;
+			}
+			rb_node = rb_next(rb_node);
+			rb_erase(&frag->node, &ci->i_fragtree);
+			kfree(frag);
+			frag = NULL;
+		}
+		if (!frag) {
+			frag = __get_or_create_frag(ci, id);
+			if (IS_ERR(frag))
+				continue;
+		}
+		frag->split_by = le32_to_cpu(fragtree->splits[i].by);
+		dout(" frag %x split by %d\n", frag->frag, frag->split_by);
+	}
+	while (rb_node) {
+		frag = rb_entry(rb_node, struct ceph_inode_frag, node);
+		rb_node = rb_next(rb_node);
+		rb_erase(&frag->node, &ci->i_fragtree);
+		kfree(frag);
+	}
+out_unlock:
+	mutex_unlock(&ci->i_fragtree_mutex);
+	return 0;
+}
+
+/*
+ * initialize a newly allocated inode.
+ */
+struct inode *ceph_alloc_inode(struct super_block *sb)
+{
+	struct ceph_inode_info *ci;
+	int i;
+
+	ci = kmem_cache_alloc(ceph_inode_cachep, GFP_NOFS);
+	if (!ci)
+		return NULL;
+
+	dout("alloc_inode %p\n", &ci->vfs_inode);
+
+	spin_lock_init(&ci->i_ceph_lock);
+
+	ci->i_version = 0;
+	ci->i_inline_version = 0;
+	ci->i_time_warp_seq = 0;
+	ci->i_ceph_flags = 0;
+	ci->i_ordered_count = 0;
+	atomic_set(&ci->i_release_count, 1);
+	atomic_set(&ci->i_complete_count, 0);
+	ci->i_symlink = NULL;
+
+	memset(&ci->i_dir_layout, 0, sizeof(ci->i_dir_layout));
+
+	ci->i_fragtree = RB_ROOT;
+	mutex_init(&ci->i_fragtree_mutex);
+
+	ci->i_xattrs.blob = NULL;
+	ci->i_xattrs.prealloc_blob = NULL;
+	ci->i_xattrs.dirty = false;
+	ci->i_xattrs.index = RB_ROOT;
+	ci->i_xattrs.count = 0;
+	ci->i_xattrs.names_size = 0;
+	ci->i_xattrs.vals_size = 0;
+	ci->i_xattrs.version = 0;
+	ci->i_xattrs.index_version = 0;
+
+	ci->i_caps = RB_ROOT;
+	ci->i_auth_cap = NULL;
+	ci->i_dirty_caps = 0;
+	ci->i_flushing_caps = 0;
+	INIT_LIST_HEAD(&ci->i_dirty_item);
+	INIT_LIST_HEAD(&ci->i_flushing_item);
+	ci->i_cap_flush_seq = 0;
+	ci->i_cap_flush_last_tid = 0;
+	memset(&ci->i_cap_flush_tid, 0, sizeof(ci->i_cap_flush_tid));
+	init_waitqueue_head(&ci->i_cap_wq);
+	ci->i_hold_caps_min = 0;
+	ci->i_hold_caps_max = 0;
+	INIT_LIST_HEAD(&ci->i_cap_delay_list);
+	INIT_LIST_HEAD(&ci->i_cap_snaps);
+	ci->i_head_snapc = NULL;
+	ci->i_snap_caps = 0;
+
+	for (i = 0; i < CEPH_FILE_MODE_NUM; i++)
+		ci->i_nr_by_mode[i] = 0;
+
+	mutex_init(&ci->i_truncate_mutex);
+	ci->i_truncate_seq = 0;
+	ci->i_truncate_size = 0;
+	ci->i_truncate_pending = 0;
+
+	ci->i_max_size = 0;
+	ci->i_reported_size = 0;
+	ci->i_wanted_max_size = 0;
+	ci->i_requested_max_size = 0;
+
+	ci->i_pin_ref = 0;
+	ci->i_rd_ref = 0;
+	ci->i_rdcache_ref = 0;
+	ci->i_wr_ref = 0;
+	ci->i_wb_ref = 0;
+	ci->i_wrbuffer_ref = 0;
+	ci->i_wrbuffer_ref_head = 0;
+	ci->i_shared_gen = 0;
+	ci->i_rdcache_gen = 0;
+	ci->i_rdcache_revoking = 0;
+
+	INIT_LIST_HEAD(&ci->i_unsafe_writes);
+	INIT_LIST_HEAD(&ci->i_unsafe_dirops);
+	spin_lock_init(&ci->i_unsafe_lock);
+
+	ci->i_snap_realm = NULL;
+	INIT_LIST_HEAD(&ci->i_snap_realm_item);
+	INIT_LIST_HEAD(&ci->i_snap_flush_item);
+
+	INIT_WORK(&ci->i_wb_work, ceph_writeback_work);
+	INIT_WORK(&ci->i_pg_inv_work, ceph_invalidate_work);
+
+	INIT_WORK(&ci->i_vmtruncate_work, ceph_vmtruncate_work);
+
+	ceph_fscache_inode_init(ci);
+
+	return &ci->vfs_inode;
+}
+
+static void ceph_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	kmem_cache_free(ceph_inode_cachep, ci);
+}
+
+void ceph_destroy_inode(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_inode_frag *frag;
+	struct rb_node *n;
+
+	dout("destroy_inode %p ino %llx.%llx\n", inode, ceph_vinop(inode));
+
+	ceph_fscache_unregister_inode_cookie(ci);
+
+	ceph_queue_caps_release(inode);
+
+	/*
+	 * we may still have a snap_realm reference if there are stray
+	 * caps in i_snap_caps.
+	 */
+	if (ci->i_snap_realm) {
+		struct ceph_mds_client *mdsc =
+			ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
+		struct ceph_snap_realm *realm = ci->i_snap_realm;
+
+		dout(" dropping residual ref to snap realm %p\n", realm);
+		spin_lock(&realm->inodes_with_caps_lock);
+		list_del_init(&ci->i_snap_realm_item);
+		spin_unlock(&realm->inodes_with_caps_lock);
+		ceph_put_snap_realm(mdsc, realm);
+	}
+
+	kfree(ci->i_symlink);
+	while ((n = rb_first(&ci->i_fragtree)) != NULL) {
+		frag = rb_entry(n, struct ceph_inode_frag, node);
+		rb_erase(n, &ci->i_fragtree);
+		kfree(frag);
+	}
+
+	__ceph_destroy_xattrs(ci);
+	if (ci->i_xattrs.blob)
+		ceph_buffer_put(ci->i_xattrs.blob);
+	if (ci->i_xattrs.prealloc_blob)
+		ceph_buffer_put(ci->i_xattrs.prealloc_blob);
+
+	call_rcu(&inode->i_rcu, ceph_i_callback);
+}
+
+int ceph_drop_inode(struct inode *inode)
+{
+	/*
+	 * Positve dentry and corresponding inode are always accompanied
+	 * in MDS reply. So no need to keep inode in the cache after
+	 * dropping all its aliases.
+	 */
+	return 1;
+}
+
+/*
+ * Helpers to fill in size, ctime, mtime, and atime.  We have to be
+ * careful because either the client or MDS may have more up to date
+ * info, depending on which capabilities are held, and whether
+ * time_warp_seq or truncate_seq have increased.  (Ordinarily, mtime
+ * and size are monotonically increasing, except when utimes() or
+ * truncate() increments the corresponding _seq values.)
+ */
+int ceph_fill_file_size(struct inode *inode, int issued,
+			u32 truncate_seq, u64 truncate_size, u64 size)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int queue_trunc = 0;
+
+	if (ceph_seq_cmp(truncate_seq, ci->i_truncate_seq) > 0 ||
+	    (truncate_seq == ci->i_truncate_seq && size > inode->i_size)) {
+		dout("size %lld -> %llu\n", inode->i_size, size);
+		inode->i_size = size;
+		inode->i_blocks = (size + (1<<9) - 1) >> 9;
+		ci->i_reported_size = size;
+		if (truncate_seq != ci->i_truncate_seq) {
+			dout("truncate_seq %u -> %u\n",
+			     ci->i_truncate_seq, truncate_seq);
+			ci->i_truncate_seq = truncate_seq;
+
+			/* the MDS should have revoked these caps */
+			WARN_ON_ONCE(issued & (CEPH_CAP_FILE_EXCL |
+					       CEPH_CAP_FILE_RD |
+					       CEPH_CAP_FILE_WR |
+					       CEPH_CAP_FILE_LAZYIO));
+			/*
+			 * If we hold relevant caps, or in the case where we're
+			 * not the only client referencing this file and we
+			 * don't hold those caps, then we need to check whether
+			 * the file is either opened or mmaped
+			 */
+			if ((issued & (CEPH_CAP_FILE_CACHE|
+				       CEPH_CAP_FILE_BUFFER)) ||
+			    mapping_mapped(inode->i_mapping) ||
+			    __ceph_caps_file_wanted(ci)) {
+				ci->i_truncate_pending++;
+				queue_trunc = 1;
+			}
+		}
+	}
+	if (ceph_seq_cmp(truncate_seq, ci->i_truncate_seq) >= 0 &&
+	    ci->i_truncate_size != truncate_size) {
+		dout("truncate_size %lld -> %llu\n", ci->i_truncate_size,
+		     truncate_size);
+		ci->i_truncate_size = truncate_size;
+	}
+
+	if (queue_trunc)
+		ceph_fscache_invalidate(inode);
+
+	return queue_trunc;
+}
+
+void ceph_fill_file_time(struct inode *inode, int issued,
+			 u64 time_warp_seq, struct timespec *ctime,
+			 struct timespec *mtime, struct timespec *atime)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int warn = 0;
+
+	if (issued & (CEPH_CAP_FILE_EXCL|
+		      CEPH_CAP_FILE_WR|
+		      CEPH_CAP_FILE_BUFFER|
+		      CEPH_CAP_AUTH_EXCL|
+		      CEPH_CAP_XATTR_EXCL)) {
+		if (timespec_compare(ctime, &inode->i_ctime) > 0) {
+			dout("ctime %ld.%09ld -> %ld.%09ld inc w/ cap\n",
+			     inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
+			     ctime->tv_sec, ctime->tv_nsec);
+			inode->i_ctime = *ctime;
+		}
+		if (ceph_seq_cmp(time_warp_seq, ci->i_time_warp_seq) > 0) {
+			/* the MDS did a utimes() */
+			dout("mtime %ld.%09ld -> %ld.%09ld "
+			     "tw %d -> %d\n",
+			     inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
+			     mtime->tv_sec, mtime->tv_nsec,
+			     ci->i_time_warp_seq, (int)time_warp_seq);
+
+			inode->i_mtime = *mtime;
+			inode->i_atime = *atime;
+			ci->i_time_warp_seq = time_warp_seq;
+		} else if (time_warp_seq == ci->i_time_warp_seq) {
+			/* nobody did utimes(); take the max */
+			if (timespec_compare(mtime, &inode->i_mtime) > 0) {
+				dout("mtime %ld.%09ld -> %ld.%09ld inc\n",
+				     inode->i_mtime.tv_sec,
+				     inode->i_mtime.tv_nsec,
+				     mtime->tv_sec, mtime->tv_nsec);
+				inode->i_mtime = *mtime;
+			}
+			if (timespec_compare(atime, &inode->i_atime) > 0) {
+				dout("atime %ld.%09ld -> %ld.%09ld inc\n",
+				     inode->i_atime.tv_sec,
+				     inode->i_atime.tv_nsec,
+				     atime->tv_sec, atime->tv_nsec);
+				inode->i_atime = *atime;
+			}
+		} else if (issued & CEPH_CAP_FILE_EXCL) {
+			/* we did a utimes(); ignore mds values */
+		} else {
+			warn = 1;
+		}
+	} else {
+		/* we have no write|excl caps; whatever the MDS says is true */
+		if (ceph_seq_cmp(time_warp_seq, ci->i_time_warp_seq) >= 0) {
+			inode->i_ctime = *ctime;
+			inode->i_mtime = *mtime;
+			inode->i_atime = *atime;
+			ci->i_time_warp_seq = time_warp_seq;
+		} else {
+			warn = 1;
+		}
+	}
+	if (warn) /* time_warp_seq shouldn't go backwards */
+		dout("%p mds time_warp_seq %llu < %u\n",
+		     inode, time_warp_seq, ci->i_time_warp_seq);
+}
+
+/*
+ * Populate an inode based on info from mds.  May be called on new or
+ * existing inodes.
+ */
+static int fill_inode(struct inode *inode, struct page *locked_page,
+		      struct ceph_mds_reply_info_in *iinfo,
+		      struct ceph_mds_reply_dirfrag *dirinfo,
+		      struct ceph_mds_session *session,
+		      unsigned long ttl_from, int cap_fmode,
+		      struct ceph_cap_reservation *caps_reservation)
+{
+	struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
+	struct ceph_mds_reply_inode *info = iinfo->in;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int issued = 0, implemented, new_issued;
+	struct timespec mtime, atime, ctime;
+	struct ceph_buffer *xattr_blob = NULL;
+	struct ceph_cap *new_cap = NULL;
+	int err = 0;
+	bool wake = false;
+	bool queue_trunc = false;
+	bool new_version = false;
+	bool fill_inline = false;
+
+	dout("fill_inode %p ino %llx.%llx v %llu had %llu\n",
+	     inode, ceph_vinop(inode), le64_to_cpu(info->version),
+	     ci->i_version);
+
+	/* prealloc new cap struct */
+	if (info->cap.caps && ceph_snap(inode) == CEPH_NOSNAP)
+		new_cap = ceph_get_cap(mdsc, caps_reservation);
+
+	/*
+	 * prealloc xattr data, if it looks like we'll need it.  only
+	 * if len > 4 (meaning there are actually xattrs; the first 4
+	 * bytes are the xattr count).
+	 */
+	if (iinfo->xattr_len > 4) {
+		xattr_blob = ceph_buffer_new(iinfo->xattr_len, GFP_NOFS);
+		if (!xattr_blob)
+			pr_err("fill_inode ENOMEM xattr blob %d bytes\n",
+			       iinfo->xattr_len);
+	}
+
+	spin_lock(&ci->i_ceph_lock);
+
+	/*
+	 * provided version will be odd if inode value is projected,
+	 * even if stable.  skip the update if we have newer stable
+	 * info (ours>=theirs, e.g. due to racing mds replies), unless
+	 * we are getting projected (unstable) info (in which case the
+	 * version is odd, and we want ours>theirs).
+	 *   us   them
+	 *   2    2     skip
+	 *   3    2     skip
+	 *   3    3     update
+	 */
+	if (ci->i_version == 0 ||
+	    ((info->cap.flags & CEPH_CAP_FLAG_AUTH) &&
+	     le64_to_cpu(info->version) > (ci->i_version & ~1)))
+		new_version = true;
+
+	issued = __ceph_caps_issued(ci, &implemented);
+	issued |= implemented | __ceph_caps_dirty(ci);
+	new_issued = ~issued & le32_to_cpu(info->cap.caps);
+
+	/* update inode */
+	ci->i_version = le64_to_cpu(info->version);
+	inode->i_version++;
+	inode->i_rdev = le32_to_cpu(info->rdev);
+	inode->i_blkbits = fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1;
+
+	if ((new_version || (new_issued & CEPH_CAP_AUTH_SHARED)) &&
+	    (issued & CEPH_CAP_AUTH_EXCL) == 0) {
+		inode->i_mode = le32_to_cpu(info->mode);
+		inode->i_uid = make_kuid(&init_user_ns, le32_to_cpu(info->uid));
+		inode->i_gid = make_kgid(&init_user_ns, le32_to_cpu(info->gid));
+		dout("%p mode 0%o uid.gid %d.%d\n", inode, inode->i_mode,
+		     from_kuid(&init_user_ns, inode->i_uid),
+		     from_kgid(&init_user_ns, inode->i_gid));
+	}
+
+	if ((new_version || (new_issued & CEPH_CAP_LINK_SHARED)) &&
+	    (issued & CEPH_CAP_LINK_EXCL) == 0)
+		set_nlink(inode, le32_to_cpu(info->nlink));
+
+	if (new_version || (new_issued & CEPH_CAP_ANY_RD)) {
+		/* be careful with mtime, atime, size */
+		ceph_decode_timespec(&atime, &info->atime);
+		ceph_decode_timespec(&mtime, &info->mtime);
+		ceph_decode_timespec(&ctime, &info->ctime);
+		ceph_fill_file_time(inode, issued,
+				le32_to_cpu(info->time_warp_seq),
+				&ctime, &mtime, &atime);
+	}
+
+	if (new_version ||
+	    (new_issued & (CEPH_CAP_ANY_FILE_RD | CEPH_CAP_ANY_FILE_WR))) {
+		ci->i_layout = info->layout;
+		queue_trunc = ceph_fill_file_size(inode, issued,
+					le32_to_cpu(info->truncate_seq),
+					le64_to_cpu(info->truncate_size),
+					le64_to_cpu(info->size));
+		/* only update max_size on auth cap */
+		if ((info->cap.flags & CEPH_CAP_FLAG_AUTH) &&
+		    ci->i_max_size != le64_to_cpu(info->max_size)) {
+			dout("max_size %lld -> %llu\n", ci->i_max_size,
+					le64_to_cpu(info->max_size));
+			ci->i_max_size = le64_to_cpu(info->max_size);
+		}
+	}
+
+	/* xattrs */
+	/* note that if i_xattrs.len <= 4, i_xattrs.data will still be NULL. */
+	if ((ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL))  &&
+	    le64_to_cpu(info->xattr_version) > ci->i_xattrs.version) {
+		if (ci->i_xattrs.blob)
+			ceph_buffer_put(ci->i_xattrs.blob);
+		ci->i_xattrs.blob = xattr_blob;
+		if (xattr_blob)
+			memcpy(ci->i_xattrs.blob->vec.iov_base,
+			       iinfo->xattr_data, iinfo->xattr_len);
+		ci->i_xattrs.version = le64_to_cpu(info->xattr_version);
+		ceph_forget_all_cached_acls(inode);
+		xattr_blob = NULL;
+	}
+
+	inode->i_mapping->a_ops = &ceph_aops;
+
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFIFO:
+	case S_IFBLK:
+	case S_IFCHR:
+	case S_IFSOCK:
+		init_special_inode(inode, inode->i_mode, inode->i_rdev);
+		inode->i_op = &ceph_file_iops;
+		break;
+	case S_IFREG:
+		inode->i_op = &ceph_file_iops;
+		inode->i_fop = &ceph_file_fops;
+		break;
+	case S_IFLNK:
+		inode->i_op = &ceph_symlink_iops;
+		if (!ci->i_symlink) {
+			u32 symlen = iinfo->symlink_len;
+			char *sym;
+
+			spin_unlock(&ci->i_ceph_lock);
+
+			err = -EINVAL;
+			if (WARN_ON(symlen != inode->i_size))
+				goto out;
+
+			err = -ENOMEM;
+			sym = kstrndup(iinfo->symlink, symlen, GFP_NOFS);
+			if (!sym)
+				goto out;
+
+			spin_lock(&ci->i_ceph_lock);
+			if (!ci->i_symlink)
+				ci->i_symlink = sym;
+			else
+				kfree(sym); /* lost a race */
+		}
+		break;
+	case S_IFDIR:
+		inode->i_op = &ceph_dir_iops;
+		inode->i_fop = &ceph_dir_fops;
+
+		ci->i_dir_layout = iinfo->dir_layout;
+
+		ci->i_files = le64_to_cpu(info->files);
+		ci->i_subdirs = le64_to_cpu(info->subdirs);
+		ci->i_rbytes = le64_to_cpu(info->rbytes);
+		ci->i_rfiles = le64_to_cpu(info->rfiles);
+		ci->i_rsubdirs = le64_to_cpu(info->rsubdirs);
+		ceph_decode_timespec(&ci->i_rctime, &info->rctime);
+		break;
+	default:
+		pr_err("fill_inode %llx.%llx BAD mode 0%o\n",
+		       ceph_vinop(inode), inode->i_mode);
+	}
+
+	/* were we issued a capability? */
+	if (info->cap.caps) {
+		if (ceph_snap(inode) == CEPH_NOSNAP) {
+			unsigned caps = le32_to_cpu(info->cap.caps);
+			ceph_add_cap(inode, session,
+				     le64_to_cpu(info->cap.cap_id),
+				     cap_fmode, caps,
+				     le32_to_cpu(info->cap.wanted),
+				     le32_to_cpu(info->cap.seq),
+				     le32_to_cpu(info->cap.mseq),
+				     le64_to_cpu(info->cap.realm),
+				     info->cap.flags, &new_cap);
+
+			/* set dir completion flag? */
+			if (S_ISDIR(inode->i_mode) &&
+			    ci->i_files == 0 && ci->i_subdirs == 0 &&
+			    (caps & CEPH_CAP_FILE_SHARED) &&
+			    (issued & CEPH_CAP_FILE_EXCL) == 0 &&
+			    !__ceph_dir_is_complete(ci)) {
+				dout(" marking %p complete (empty)\n", inode);
+				__ceph_dir_set_complete(ci,
+					atomic_read(&ci->i_release_count),
+					ci->i_ordered_count);
+			}
+
+			wake = true;
+		} else {
+			dout(" %p got snap_caps %s\n", inode,
+			     ceph_cap_string(le32_to_cpu(info->cap.caps)));
+			ci->i_snap_caps |= le32_to_cpu(info->cap.caps);
+			if (cap_fmode >= 0)
+				__ceph_get_fmode(ci, cap_fmode);
+		}
+	} else if (cap_fmode >= 0) {
+		pr_warn("mds issued no caps on %llx.%llx\n",
+			   ceph_vinop(inode));
+		__ceph_get_fmode(ci, cap_fmode);
+	}
+
+	if (iinfo->inline_version > 0 &&
+	    iinfo->inline_version >= ci->i_inline_version) {
+		int cache_caps = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
+		ci->i_inline_version = iinfo->inline_version;
+		if (ci->i_inline_version != CEPH_INLINE_NONE &&
+		    (locked_page ||
+		     (le32_to_cpu(info->cap.caps) & cache_caps)))
+			fill_inline = true;
+	}
+
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (fill_inline)
+		ceph_fill_inline_data(inode, locked_page,
+				      iinfo->inline_data, iinfo->inline_len);
+
+	if (wake)
+		wake_up_all(&ci->i_cap_wq);
+
+	/* queue truncate if we saw i_size decrease */
+	if (queue_trunc)
+		ceph_queue_vmtruncate(inode);
+
+	/* populate frag tree */
+	if (S_ISDIR(inode->i_mode))
+		ceph_fill_fragtree(inode, &info->fragtree, dirinfo);
+
+	/* update delegation info? */
+	if (dirinfo)
+		ceph_fill_dirfrag(inode, dirinfo);
+
+	err = 0;
+out:
+	if (new_cap)
+		ceph_put_cap(mdsc, new_cap);
+	if (xattr_blob)
+		ceph_buffer_put(xattr_blob);
+	return err;
+}
+
+/*
+ * caller should hold session s_mutex.
+ */
+static void update_dentry_lease(struct dentry *dentry,
+				struct ceph_mds_reply_lease *lease,
+				struct ceph_mds_session *session,
+				unsigned long from_time)
+{
+	struct ceph_dentry_info *di = ceph_dentry(dentry);
+	long unsigned duration = le32_to_cpu(lease->duration_ms);
+	long unsigned ttl = from_time + (duration * HZ) / 1000;
+	long unsigned half_ttl = from_time + (duration * HZ / 2) / 1000;
+	struct inode *dir;
+
+	/* only track leases on regular dentries */
+	if (dentry->d_op != &ceph_dentry_ops)
+		return;
+
+	spin_lock(&dentry->d_lock);
+	dout("update_dentry_lease %p duration %lu ms ttl %lu\n",
+	     dentry, duration, ttl);
+
+	/* make lease_rdcache_gen match directory */
+	dir = d_inode(dentry->d_parent);
+	di->lease_shared_gen = ceph_inode(dir)->i_shared_gen;
+
+	if (duration == 0)
+		goto out_unlock;
+
+	if (di->lease_gen == session->s_cap_gen &&
+	    time_before(ttl, dentry->d_time))
+		goto out_unlock;  /* we already have a newer lease. */
+
+	if (di->lease_session && di->lease_session != session)
+		goto out_unlock;
+
+	ceph_dentry_lru_touch(dentry);
+
+	if (!di->lease_session)
+		di->lease_session = ceph_get_mds_session(session);
+	di->lease_gen = session->s_cap_gen;
+	di->lease_seq = le32_to_cpu(lease->seq);
+	di->lease_renew_after = half_ttl;
+	di->lease_renew_from = 0;
+	dentry->d_time = ttl;
+out_unlock:
+	spin_unlock(&dentry->d_lock);
+	return;
+}
+
+/*
+ * splice a dentry to an inode.
+ * caller must hold directory i_mutex for this to be safe.
+ *
+ * we will only rehash the resulting dentry if @prehash is
+ * true; @prehash will be set to false (for the benefit of
+ * the caller) if we fail.
+ */
+static struct dentry *splice_dentry(struct dentry *dn, struct inode *in,
+				    bool *prehash)
+{
+	struct dentry *realdn;
+
+	BUG_ON(d_inode(dn));
+
+	/* dn must be unhashed */
+	if (!d_unhashed(dn))
+		d_drop(dn);
+	realdn = d_splice_alias(in, dn);
+	if (IS_ERR(realdn)) {
+		pr_err("splice_dentry error %ld %p inode %p ino %llx.%llx\n",
+		       PTR_ERR(realdn), dn, in, ceph_vinop(in));
+		if (prehash)
+			*prehash = false; /* don't rehash on error */
+		dn = realdn; /* note realdn contains the error */
+		goto out;
+	} else if (realdn) {
+		dout("dn %p (%d) spliced with %p (%d) "
+		     "inode %p ino %llx.%llx\n",
+		     dn, d_count(dn),
+		     realdn, d_count(realdn),
+		     d_inode(realdn), ceph_vinop(d_inode(realdn)));
+		dput(dn);
+		dn = realdn;
+	} else {
+		BUG_ON(!ceph_dentry(dn));
+		dout("dn %p attached to %p ino %llx.%llx\n",
+		     dn, d_inode(dn), ceph_vinop(d_inode(dn)));
+	}
+	if ((!prehash || *prehash) && d_unhashed(dn))
+		d_rehash(dn);
+out:
+	return dn;
+}
+
+/*
+ * Incorporate results into the local cache.  This is either just
+ * one inode, or a directory, dentry, and possibly linked-to inode (e.g.,
+ * after a lookup).
+ *
+ * A reply may contain
+ *         a directory inode along with a dentry.
+ *  and/or a target inode
+ *
+ * Called with snap_rwsem (read).
+ */
+int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
+		    struct ceph_mds_session *session)
+{
+	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
+	struct inode *in = NULL;
+	struct ceph_vino vino;
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+	int err = 0;
+
+	dout("fill_trace %p is_dentry %d is_target %d\n", req,
+	     rinfo->head->is_dentry, rinfo->head->is_target);
+
+#if 0
+	/*
+	 * Debugging hook:
+	 *
+	 * If we resend completed ops to a recovering mds, we get no
+	 * trace.  Since that is very rare, pretend this is the case
+	 * to ensure the 'no trace' handlers in the callers behave.
+	 *
+	 * Fill in inodes unconditionally to avoid breaking cap
+	 * invariants.
+	 */
+	if (rinfo->head->op & CEPH_MDS_OP_WRITE) {
+		pr_info("fill_trace faking empty trace on %lld %s\n",
+			req->r_tid, ceph_mds_op_name(rinfo->head->op));
+		if (rinfo->head->is_dentry) {
+			rinfo->head->is_dentry = 0;
+			err = fill_inode(req->r_locked_dir,
+					 &rinfo->diri, rinfo->dirfrag,
+					 session, req->r_request_started, -1);
+		}
+		if (rinfo->head->is_target) {
+			rinfo->head->is_target = 0;
+			ininfo = rinfo->targeti.in;
+			vino.ino = le64_to_cpu(ininfo->ino);
+			vino.snap = le64_to_cpu(ininfo->snapid);
+			in = ceph_get_inode(sb, vino);
+			err = fill_inode(in, &rinfo->targeti, NULL,
+					 session, req->r_request_started,
+					 req->r_fmode);
+			iput(in);
+		}
+	}
+#endif
+
+	if (!rinfo->head->is_target && !rinfo->head->is_dentry) {
+		dout("fill_trace reply is empty!\n");
+		if (rinfo->head->result == 0 && req->r_locked_dir)
+			ceph_invalidate_dir_request(req);
+		return 0;
+	}
+
+	if (rinfo->head->is_dentry) {
+		struct inode *dir = req->r_locked_dir;
+
+		if (dir) {
+			err = fill_inode(dir, NULL,
+					 &rinfo->diri, rinfo->dirfrag,
+					 session, req->r_request_started, -1,
+					 &req->r_caps_reservation);
+			if (err < 0)
+				goto done;
+		} else {
+			WARN_ON_ONCE(1);
+		}
+
+		if (dir && req->r_op == CEPH_MDS_OP_LOOKUPNAME) {
+			struct qstr dname;
+			struct dentry *dn, *parent;
+
+			BUG_ON(!rinfo->head->is_target);
+			BUG_ON(req->r_dentry);
+
+			parent = d_find_any_alias(dir);
+			BUG_ON(!parent);
+
+			dname.name = rinfo->dname;
+			dname.len = rinfo->dname_len;
+			dname.hash = full_name_hash(dname.name, dname.len);
+			vino.ino = le64_to_cpu(rinfo->targeti.in->ino);
+			vino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
+retry_lookup:
+			dn = d_lookup(parent, &dname);
+			dout("d_lookup on parent=%p name=%.*s got %p\n",
+			     parent, dname.len, dname.name, dn);
+
+			if (!dn) {
+				dn = d_alloc(parent, &dname);
+				dout("d_alloc %p '%.*s' = %p\n", parent,
+				     dname.len, dname.name, dn);
+				if (dn == NULL) {
+					dput(parent);
+					err = -ENOMEM;
+					goto done;
+				}
+				err = ceph_init_dentry(dn);
+				if (err < 0) {
+					dput(dn);
+					dput(parent);
+					goto done;
+				}
+			} else if (d_really_is_positive(dn) &&
+				   (ceph_ino(d_inode(dn)) != vino.ino ||
+				    ceph_snap(d_inode(dn)) != vino.snap)) {
+				dout(" dn %p points to wrong inode %p\n",
+				     dn, d_inode(dn));
+				d_delete(dn);
+				dput(dn);
+				goto retry_lookup;
+			}
+
+			req->r_dentry = dn;
+			dput(parent);
+		}
+	}
+
+	if (rinfo->head->is_target) {
+		vino.ino = le64_to_cpu(rinfo->targeti.in->ino);
+		vino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
+
+		in = ceph_get_inode(sb, vino);
+		if (IS_ERR(in)) {
+			err = PTR_ERR(in);
+			goto done;
+		}
+		req->r_target_inode = in;
+
+		err = fill_inode(in, req->r_locked_page, &rinfo->targeti, NULL,
+				session, req->r_request_started,
+				(!req->r_aborted && rinfo->head->result == 0) ?
+				req->r_fmode : -1,
+				&req->r_caps_reservation);
+		if (err < 0) {
+			pr_err("fill_inode badness %p %llx.%llx\n",
+				in, ceph_vinop(in));
+			goto done;
+		}
+	}
+
+	/*
+	 * ignore null lease/binding on snapdir ENOENT, or else we
+	 * will have trouble splicing in the virtual snapdir later
+	 */
+	if (rinfo->head->is_dentry && !req->r_aborted &&
+	    req->r_locked_dir &&
+	    (rinfo->head->is_target || strncmp(req->r_dentry->d_name.name,
+					       fsc->mount_options->snapdir_name,
+					       req->r_dentry->d_name.len))) {
+		/*
+		 * lookup link rename   : null -> possibly existing inode
+		 * mknod symlink mkdir  : null -> new inode
+		 * unlink               : linked -> null
+		 */
+		struct inode *dir = req->r_locked_dir;
+		struct dentry *dn = req->r_dentry;
+		bool have_dir_cap, have_lease;
+
+		BUG_ON(!dn);
+		BUG_ON(!dir);
+		BUG_ON(d_inode(dn->d_parent) != dir);
+		BUG_ON(ceph_ino(dir) !=
+		       le64_to_cpu(rinfo->diri.in->ino));
+		BUG_ON(ceph_snap(dir) !=
+		       le64_to_cpu(rinfo->diri.in->snapid));
+
+		/* do we have a lease on the whole dir? */
+		have_dir_cap =
+			(le32_to_cpu(rinfo->diri.in->cap.caps) &
+			 CEPH_CAP_FILE_SHARED);
+
+		/* do we have a dn lease? */
+		have_lease = have_dir_cap ||
+			le32_to_cpu(rinfo->dlease->duration_ms);
+		if (!have_lease)
+			dout("fill_trace  no dentry lease or dir cap\n");
+
+		/* rename? */
+		if (req->r_old_dentry && req->r_op == CEPH_MDS_OP_RENAME) {
+			struct inode *olddir = req->r_old_dentry_dir;
+			BUG_ON(!olddir);
+
+			dout(" src %p '%pd' dst %p '%pd'\n",
+			     req->r_old_dentry,
+			     req->r_old_dentry,
+			     dn, dn);
+			dout("fill_trace doing d_move %p -> %p\n",
+			     req->r_old_dentry, dn);
+
+			d_move(req->r_old_dentry, dn);
+			dout(" src %p '%pd' dst %p '%pd'\n",
+			     req->r_old_dentry,
+			     req->r_old_dentry,
+			     dn, dn);
+
+			/* ensure target dentry is invalidated, despite
+			   rehashing bug in vfs_rename_dir */
+			ceph_invalidate_dentry_lease(dn);
+
+			/* d_move screws up sibling dentries' offsets */
+			ceph_dir_clear_ordered(dir);
+			ceph_dir_clear_ordered(olddir);
+
+			dout("dn %p gets new offset %lld\n", req->r_old_dentry,
+			     ceph_dentry(req->r_old_dentry)->offset);
+
+			dn = req->r_old_dentry;  /* use old_dentry */
+		}
+
+		/* null dentry? */
+		if (!rinfo->head->is_target) {
+			dout("fill_trace null dentry\n");
+			if (d_really_is_positive(dn)) {
+				ceph_dir_clear_ordered(dir);
+				dout("d_delete %p\n", dn);
+				d_delete(dn);
+			} else {
+				dout("d_instantiate %p NULL\n", dn);
+				d_instantiate(dn, NULL);
+				if (have_lease && d_unhashed(dn))
+					d_rehash(dn);
+				update_dentry_lease(dn, rinfo->dlease,
+						    session,
+						    req->r_request_started);
+			}
+			goto done;
+		}
+
+		/* attach proper inode */
+		if (d_really_is_negative(dn)) {
+			ceph_dir_clear_ordered(dir);
+			ihold(in);
+			dn = splice_dentry(dn, in, &have_lease);
+			if (IS_ERR(dn)) {
+				err = PTR_ERR(dn);
+				goto done;
+			}
+			req->r_dentry = dn;  /* may have spliced */
+		} else if (d_really_is_positive(dn) && d_inode(dn) != in) {
+			dout(" %p links to %p %llx.%llx, not %llx.%llx\n",
+			     dn, d_inode(dn), ceph_vinop(d_inode(dn)),
+			     ceph_vinop(in));
+			have_lease = false;
+		}
+
+		if (have_lease)
+			update_dentry_lease(dn, rinfo->dlease, session,
+					    req->r_request_started);
+		dout(" final dn %p\n", dn);
+	} else if (!req->r_aborted &&
+		   (req->r_op == CEPH_MDS_OP_LOOKUPSNAP ||
+		    req->r_op == CEPH_MDS_OP_MKSNAP)) {
+		struct dentry *dn = req->r_dentry;
+		struct inode *dir = req->r_locked_dir;
+
+		/* fill out a snapdir LOOKUPSNAP dentry */
+		BUG_ON(!dn);
+		BUG_ON(!dir);
+		BUG_ON(ceph_snap(dir) != CEPH_SNAPDIR);
+		dout(" linking snapped dir %p to dn %p\n", in, dn);
+		ceph_dir_clear_ordered(dir);
+		ihold(in);
+		dn = splice_dentry(dn, in, NULL);
+		if (IS_ERR(dn)) {
+			err = PTR_ERR(dn);
+			goto done;
+		}
+		req->r_dentry = dn;  /* may have spliced */
+	}
+done:
+	dout("fill_trace done err=%d\n", err);
+	return err;
+}
+
+/*
+ * Prepopulate our cache with readdir results, leases, etc.
+ */
+static int readdir_prepopulate_inodes_only(struct ceph_mds_request *req,
+					   struct ceph_mds_session *session)
+{
+	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
+	int i, err = 0;
+
+	for (i = 0; i < rinfo->dir_nr; i++) {
+		struct ceph_vino vino;
+		struct inode *in;
+		int rc;
+
+		vino.ino = le64_to_cpu(rinfo->dir_in[i].in->ino);
+		vino.snap = le64_to_cpu(rinfo->dir_in[i].in->snapid);
+
+		in = ceph_get_inode(req->r_dentry->d_sb, vino);
+		if (IS_ERR(in)) {
+			err = PTR_ERR(in);
+			dout("new_inode badness got %d\n", err);
+			continue;
+		}
+		rc = fill_inode(in, NULL, &rinfo->dir_in[i], NULL, session,
+				req->r_request_started, -1,
+				&req->r_caps_reservation);
+		if (rc < 0) {
+			pr_err("fill_inode badness on %p got %d\n", in, rc);
+			err = rc;
+			continue;
+		}
+	}
+
+	return err;
+}
+
+int ceph_readdir_prepopulate(struct ceph_mds_request *req,
+			     struct ceph_mds_session *session)
+{
+	struct dentry *parent = req->r_dentry;
+	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
+	struct qstr dname;
+	struct dentry *dn;
+	struct inode *in;
+	int err = 0, ret, i;
+	struct inode *snapdir = NULL;
+	struct ceph_mds_request_head *rhead = req->r_request->front.iov_base;
+	struct ceph_dentry_info *di;
+	u64 r_readdir_offset = req->r_readdir_offset;
+	u32 frag = le32_to_cpu(rhead->args.readdir.frag);
+
+	if (rinfo->dir_dir &&
+	    le32_to_cpu(rinfo->dir_dir->frag) != frag) {
+		dout("readdir_prepopulate got new frag %x -> %x\n",
+		     frag, le32_to_cpu(rinfo->dir_dir->frag));
+		frag = le32_to_cpu(rinfo->dir_dir->frag);
+		if (ceph_frag_is_leftmost(frag))
+			r_readdir_offset = 2;
+		else
+			r_readdir_offset = 0;
+	}
+
+	if (req->r_aborted)
+		return readdir_prepopulate_inodes_only(req, session);
+
+	if (le32_to_cpu(rinfo->head->op) == CEPH_MDS_OP_LSSNAP) {
+		snapdir = ceph_get_snapdir(d_inode(parent));
+		parent = d_find_alias(snapdir);
+		dout("readdir_prepopulate %d items under SNAPDIR dn %p\n",
+		     rinfo->dir_nr, parent);
+	} else {
+		dout("readdir_prepopulate %d items under dn %p\n",
+		     rinfo->dir_nr, parent);
+		if (rinfo->dir_dir)
+			ceph_fill_dirfrag(d_inode(parent), rinfo->dir_dir);
+	}
+
+	/* FIXME: release caps/leases if error occurs */
+	for (i = 0; i < rinfo->dir_nr; i++) {
+		struct ceph_vino vino;
+
+		dname.name = rinfo->dir_dname[i];
+		dname.len = rinfo->dir_dname_len[i];
+		dname.hash = full_name_hash(dname.name, dname.len);
+
+		vino.ino = le64_to_cpu(rinfo->dir_in[i].in->ino);
+		vino.snap = le64_to_cpu(rinfo->dir_in[i].in->snapid);
+
+retry_lookup:
+		dn = d_lookup(parent, &dname);
+		dout("d_lookup on parent=%p name=%.*s got %p\n",
+		     parent, dname.len, dname.name, dn);
+
+		if (!dn) {
+			dn = d_alloc(parent, &dname);
+			dout("d_alloc %p '%.*s' = %p\n", parent,
+			     dname.len, dname.name, dn);
+			if (dn == NULL) {
+				dout("d_alloc badness\n");
+				err = -ENOMEM;
+				goto out;
+			}
+			ret = ceph_init_dentry(dn);
+			if (ret < 0) {
+				dput(dn);
+				err = ret;
+				goto out;
+			}
+		} else if (d_really_is_positive(dn) &&
+			   (ceph_ino(d_inode(dn)) != vino.ino ||
+			    ceph_snap(d_inode(dn)) != vino.snap)) {
+			dout(" dn %p points to wrong inode %p\n",
+			     dn, d_inode(dn));
+			d_delete(dn);
+			dput(dn);
+			goto retry_lookup;
+		} else {
+			/* reorder parent's d_subdirs */
+			spin_lock(&parent->d_lock);
+			spin_lock_nested(&dn->d_lock, DENTRY_D_LOCK_NESTED);
+			list_move(&dn->d_child, &parent->d_subdirs);
+			spin_unlock(&dn->d_lock);
+			spin_unlock(&parent->d_lock);
+		}
+
+		/* inode */
+		if (d_really_is_positive(dn)) {
+			in = d_inode(dn);
+		} else {
+			in = ceph_get_inode(parent->d_sb, vino);
+			if (IS_ERR(in)) {
+				dout("new_inode badness\n");
+				d_drop(dn);
+				dput(dn);
+				err = PTR_ERR(in);
+				goto out;
+			}
+		}
+
+		if (fill_inode(in, NULL, &rinfo->dir_in[i], NULL, session,
+			       req->r_request_started, -1,
+			       &req->r_caps_reservation) < 0) {
+			pr_err("fill_inode badness on %p\n", in);
+			if (d_really_is_negative(dn))
+				iput(in);
+			d_drop(dn);
+			goto next_item;
+		}
+
+		if (d_really_is_negative(dn)) {
+			struct dentry *realdn = splice_dentry(dn, in, NULL);
+			if (IS_ERR(realdn)) {
+				err = PTR_ERR(realdn);
+				d_drop(dn);
+				dn = NULL;
+				goto next_item;
+			}
+			dn = realdn;
+		}
+
+		di = dn->d_fsdata;
+		di->offset = ceph_make_fpos(frag, i + r_readdir_offset);
+
+		update_dentry_lease(dn, rinfo->dir_dlease[i],
+				    req->r_session,
+				    req->r_request_started);
+next_item:
+		if (dn)
+			dput(dn);
+	}
+	if (err == 0)
+		req->r_did_prepopulate = true;
+
+out:
+	if (snapdir) {
+		iput(snapdir);
+		dput(parent);
+	}
+	dout("readdir_prepopulate done\n");
+	return err;
+}
+
+int ceph_inode_set_size(struct inode *inode, loff_t size)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int ret = 0;
+
+	spin_lock(&ci->i_ceph_lock);
+	dout("set_size %p %llu -> %llu\n", inode, inode->i_size, size);
+	inode->i_size = size;
+	inode->i_blocks = (size + (1 << 9) - 1) >> 9;
+
+	/* tell the MDS if we are approaching max_size */
+	if ((size << 1) >= ci->i_max_size &&
+	    (ci->i_reported_size << 1) < ci->i_max_size)
+		ret = 1;
+
+	spin_unlock(&ci->i_ceph_lock);
+	return ret;
+}
+
+/*
+ * Write back inode data in a worker thread.  (This can't be done
+ * in the message handler context.)
+ */
+void ceph_queue_writeback(struct inode *inode)
+{
+	ihold(inode);
+	if (queue_work(ceph_inode_to_client(inode)->wb_wq,
+		       &ceph_inode(inode)->i_wb_work)) {
+		dout("ceph_queue_writeback %p\n", inode);
+	} else {
+		dout("ceph_queue_writeback %p failed\n", inode);
+		iput(inode);
+	}
+}
+
+static void ceph_writeback_work(struct work_struct *work)
+{
+	struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
+						  i_wb_work);
+	struct inode *inode = &ci->vfs_inode;
+
+	dout("writeback %p\n", inode);
+	filemap_fdatawrite(&inode->i_data);
+	iput(inode);
+}
+
+/*
+ * queue an async invalidation
+ */
+void ceph_queue_invalidate(struct inode *inode)
+{
+	ihold(inode);
+	if (queue_work(ceph_inode_to_client(inode)->pg_inv_wq,
+		       &ceph_inode(inode)->i_pg_inv_work)) {
+		dout("ceph_queue_invalidate %p\n", inode);
+	} else {
+		dout("ceph_queue_invalidate %p failed\n", inode);
+		iput(inode);
+	}
+}
+
+/*
+ * Invalidate inode pages in a worker thread.  (This can't be done
+ * in the message handler context.)
+ */
+static void ceph_invalidate_work(struct work_struct *work)
+{
+	struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
+						  i_pg_inv_work);
+	struct inode *inode = &ci->vfs_inode;
+	u32 orig_gen;
+	int check = 0;
+
+	mutex_lock(&ci->i_truncate_mutex);
+	spin_lock(&ci->i_ceph_lock);
+	dout("invalidate_pages %p gen %d revoking %d\n", inode,
+	     ci->i_rdcache_gen, ci->i_rdcache_revoking);
+	if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
+		if (__ceph_caps_revoking_other(ci, NULL, CEPH_CAP_FILE_CACHE))
+			check = 1;
+		spin_unlock(&ci->i_ceph_lock);
+		mutex_unlock(&ci->i_truncate_mutex);
+		goto out;
+	}
+	orig_gen = ci->i_rdcache_gen;
+	spin_unlock(&ci->i_ceph_lock);
+
+	truncate_pagecache(inode, 0);
+
+	spin_lock(&ci->i_ceph_lock);
+	if (orig_gen == ci->i_rdcache_gen &&
+	    orig_gen == ci->i_rdcache_revoking) {
+		dout("invalidate_pages %p gen %d successful\n", inode,
+		     ci->i_rdcache_gen);
+		ci->i_rdcache_revoking--;
+		check = 1;
+	} else {
+		dout("invalidate_pages %p gen %d raced, now %d revoking %d\n",
+		     inode, orig_gen, ci->i_rdcache_gen,
+		     ci->i_rdcache_revoking);
+		if (__ceph_caps_revoking_other(ci, NULL, CEPH_CAP_FILE_CACHE))
+			check = 1;
+	}
+	spin_unlock(&ci->i_ceph_lock);
+	mutex_unlock(&ci->i_truncate_mutex);
+out:
+	if (check)
+		ceph_check_caps(ci, 0, NULL);
+	iput(inode);
+}
+
+
+/*
+ * called by trunc_wq;
+ *
+ * We also truncate in a separate thread as well.
+ */
+static void ceph_vmtruncate_work(struct work_struct *work)
+{
+	struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
+						  i_vmtruncate_work);
+	struct inode *inode = &ci->vfs_inode;
+
+	dout("vmtruncate_work %p\n", inode);
+	__ceph_do_pending_vmtruncate(inode);
+	iput(inode);
+}
+
+/*
+ * Queue an async vmtruncate.  If we fail to queue work, we will handle
+ * the truncation the next time we call __ceph_do_pending_vmtruncate.
+ */
+void ceph_queue_vmtruncate(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	ihold(inode);
+
+	if (queue_work(ceph_sb_to_client(inode->i_sb)->trunc_wq,
+		       &ci->i_vmtruncate_work)) {
+		dout("ceph_queue_vmtruncate %p\n", inode);
+	} else {
+		dout("ceph_queue_vmtruncate %p failed, pending=%d\n",
+		     inode, ci->i_truncate_pending);
+		iput(inode);
+	}
+}
+
+/*
+ * Make sure any pending truncation is applied before doing anything
+ * that may depend on it.
+ */
+void __ceph_do_pending_vmtruncate(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	u64 to;
+	int wrbuffer_refs, finish = 0;
+
+	mutex_lock(&ci->i_truncate_mutex);
+retry:
+	spin_lock(&ci->i_ceph_lock);
+	if (ci->i_truncate_pending == 0) {
+		dout("__do_pending_vmtruncate %p none pending\n", inode);
+		spin_unlock(&ci->i_ceph_lock);
+		mutex_unlock(&ci->i_truncate_mutex);
+		return;
+	}
+
+	/*
+	 * make sure any dirty snapped pages are flushed before we
+	 * possibly truncate them.. so write AND block!
+	 */
+	if (ci->i_wrbuffer_ref_head < ci->i_wrbuffer_ref) {
+		dout("__do_pending_vmtruncate %p flushing snaps first\n",
+		     inode);
+		spin_unlock(&ci->i_ceph_lock);
+		filemap_write_and_wait_range(&inode->i_data, 0,
+					     inode->i_sb->s_maxbytes);
+		goto retry;
+	}
+
+	/* there should be no reader or writer */
+	WARN_ON_ONCE(ci->i_rd_ref || ci->i_wr_ref);
+
+	to = ci->i_truncate_size;
+	wrbuffer_refs = ci->i_wrbuffer_ref;
+	dout("__do_pending_vmtruncate %p (%d) to %lld\n", inode,
+	     ci->i_truncate_pending, to);
+	spin_unlock(&ci->i_ceph_lock);
+
+	truncate_pagecache(inode, to);
+
+	spin_lock(&ci->i_ceph_lock);
+	if (to == ci->i_truncate_size) {
+		ci->i_truncate_pending = 0;
+		finish = 1;
+	}
+	spin_unlock(&ci->i_ceph_lock);
+	if (!finish)
+		goto retry;
+
+	mutex_unlock(&ci->i_truncate_mutex);
+
+	if (wrbuffer_refs == 0)
+		ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
+
+	wake_up_all(&ci->i_cap_wq);
+}
+
+/*
+ * symlinks
+ */
+static void *ceph_sym_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct ceph_inode_info *ci = ceph_inode(d_inode(dentry));
+	nd_set_link(nd, ci->i_symlink);
+	return NULL;
+}
+
+static const struct inode_operations ceph_symlink_iops = {
+	.readlink = generic_readlink,
+	.follow_link = ceph_sym_follow_link,
+	.setattr = ceph_setattr,
+	.getattr = ceph_getattr,
+	.setxattr = ceph_setxattr,
+	.getxattr = ceph_getxattr,
+	.listxattr = ceph_listxattr,
+	.removexattr = ceph_removexattr,
+};
+
+/*
+ * setattr
+ */
+int ceph_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	const unsigned int ia_valid = attr->ia_valid;
+	struct ceph_mds_request *req;
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(dentry->d_sb)->mdsc;
+	int issued;
+	int release = 0, dirtied = 0;
+	int mask = 0;
+	int err = 0;
+	int inode_dirty_flags = 0;
+
+	if (ceph_snap(inode) != CEPH_NOSNAP)
+		return -EROFS;
+
+	err = inode_change_ok(inode, attr);
+	if (err != 0)
+		return err;
+
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETATTR,
+				       USE_AUTH_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	spin_lock(&ci->i_ceph_lock);
+	issued = __ceph_caps_issued(ci, NULL);
+	dout("setattr %p issued %s\n", inode, ceph_cap_string(issued));
+
+	if (ia_valid & ATTR_UID) {
+		dout("setattr %p uid %d -> %d\n", inode,
+		     from_kuid(&init_user_ns, inode->i_uid),
+		     from_kuid(&init_user_ns, attr->ia_uid));
+		if (issued & CEPH_CAP_AUTH_EXCL) {
+			inode->i_uid = attr->ia_uid;
+			dirtied |= CEPH_CAP_AUTH_EXCL;
+		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
+			   !uid_eq(attr->ia_uid, inode->i_uid)) {
+			req->r_args.setattr.uid = cpu_to_le32(
+				from_kuid(&init_user_ns, attr->ia_uid));
+			mask |= CEPH_SETATTR_UID;
+			release |= CEPH_CAP_AUTH_SHARED;
+		}
+	}
+	if (ia_valid & ATTR_GID) {
+		dout("setattr %p gid %d -> %d\n", inode,
+		     from_kgid(&init_user_ns, inode->i_gid),
+		     from_kgid(&init_user_ns, attr->ia_gid));
+		if (issued & CEPH_CAP_AUTH_EXCL) {
+			inode->i_gid = attr->ia_gid;
+			dirtied |= CEPH_CAP_AUTH_EXCL;
+		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
+			   !gid_eq(attr->ia_gid, inode->i_gid)) {
+			req->r_args.setattr.gid = cpu_to_le32(
+				from_kgid(&init_user_ns, attr->ia_gid));
+			mask |= CEPH_SETATTR_GID;
+			release |= CEPH_CAP_AUTH_SHARED;
+		}
+	}
+	if (ia_valid & ATTR_MODE) {
+		dout("setattr %p mode 0%o -> 0%o\n", inode, inode->i_mode,
+		     attr->ia_mode);
+		if (issued & CEPH_CAP_AUTH_EXCL) {
+			inode->i_mode = attr->ia_mode;
+			dirtied |= CEPH_CAP_AUTH_EXCL;
+		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
+			   attr->ia_mode != inode->i_mode) {
+			inode->i_mode = attr->ia_mode;
+			req->r_args.setattr.mode = cpu_to_le32(attr->ia_mode);
+			mask |= CEPH_SETATTR_MODE;
+			release |= CEPH_CAP_AUTH_SHARED;
+		}
+	}
+
+	if (ia_valid & ATTR_ATIME) {
+		dout("setattr %p atime %ld.%ld -> %ld.%ld\n", inode,
+		     inode->i_atime.tv_sec, inode->i_atime.tv_nsec,
+		     attr->ia_atime.tv_sec, attr->ia_atime.tv_nsec);
+		if (issued & CEPH_CAP_FILE_EXCL) {
+			ci->i_time_warp_seq++;
+			inode->i_atime = attr->ia_atime;
+			dirtied |= CEPH_CAP_FILE_EXCL;
+		} else if ((issued & CEPH_CAP_FILE_WR) &&
+			   timespec_compare(&inode->i_atime,
+					    &attr->ia_atime) < 0) {
+			inode->i_atime = attr->ia_atime;
+			dirtied |= CEPH_CAP_FILE_WR;
+		} else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
+			   !timespec_equal(&inode->i_atime, &attr->ia_atime)) {
+			ceph_encode_timespec(&req->r_args.setattr.atime,
+					     &attr->ia_atime);
+			mask |= CEPH_SETATTR_ATIME;
+			release |= CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_RD |
+				CEPH_CAP_FILE_WR;
+		}
+	}
+	if (ia_valid & ATTR_MTIME) {
+		dout("setattr %p mtime %ld.%ld -> %ld.%ld\n", inode,
+		     inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
+		     attr->ia_mtime.tv_sec, attr->ia_mtime.tv_nsec);
+		if (issued & CEPH_CAP_FILE_EXCL) {
+			ci->i_time_warp_seq++;
+			inode->i_mtime = attr->ia_mtime;
+			dirtied |= CEPH_CAP_FILE_EXCL;
+		} else if ((issued & CEPH_CAP_FILE_WR) &&
+			   timespec_compare(&inode->i_mtime,
+					    &attr->ia_mtime) < 0) {
+			inode->i_mtime = attr->ia_mtime;
+			dirtied |= CEPH_CAP_FILE_WR;
+		} else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
+			   !timespec_equal(&inode->i_mtime, &attr->ia_mtime)) {
+			ceph_encode_timespec(&req->r_args.setattr.mtime,
+					     &attr->ia_mtime);
+			mask |= CEPH_SETATTR_MTIME;
+			release |= CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_RD |
+				CEPH_CAP_FILE_WR;
+		}
+	}
+	if (ia_valid & ATTR_SIZE) {
+		dout("setattr %p size %lld -> %lld\n", inode,
+		     inode->i_size, attr->ia_size);
+		if ((issued & CEPH_CAP_FILE_EXCL) &&
+		    attr->ia_size > inode->i_size) {
+			inode->i_size = attr->ia_size;
+			inode->i_blocks =
+				(attr->ia_size + (1 << 9) - 1) >> 9;
+			inode->i_ctime = attr->ia_ctime;
+			ci->i_reported_size = attr->ia_size;
+			dirtied |= CEPH_CAP_FILE_EXCL;
+		} else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
+			   attr->ia_size != inode->i_size) {
+			req->r_args.setattr.size = cpu_to_le64(attr->ia_size);
+			req->r_args.setattr.old_size =
+				cpu_to_le64(inode->i_size);
+			mask |= CEPH_SETATTR_SIZE;
+			release |= CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_RD |
+				CEPH_CAP_FILE_WR;
+		}
+	}
+
+	/* these do nothing */
+	if (ia_valid & ATTR_CTIME) {
+		bool only = (ia_valid & (ATTR_SIZE|ATTR_MTIME|ATTR_ATIME|
+					 ATTR_MODE|ATTR_UID|ATTR_GID)) == 0;
+		dout("setattr %p ctime %ld.%ld -> %ld.%ld (%s)\n", inode,
+		     inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
+		     attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec,
+		     only ? "ctime only" : "ignored");
+		inode->i_ctime = attr->ia_ctime;
+		if (only) {
+			/*
+			 * if kernel wants to dirty ctime but nothing else,
+			 * we need to choose a cap to dirty under, or do
+			 * a almost-no-op setattr
+			 */
+			if (issued & CEPH_CAP_AUTH_EXCL)
+				dirtied |= CEPH_CAP_AUTH_EXCL;
+			else if (issued & CEPH_CAP_FILE_EXCL)
+				dirtied |= CEPH_CAP_FILE_EXCL;
+			else if (issued & CEPH_CAP_XATTR_EXCL)
+				dirtied |= CEPH_CAP_XATTR_EXCL;
+			else
+				mask |= CEPH_SETATTR_CTIME;
+		}
+	}
+	if (ia_valid & ATTR_FILE)
+		dout("setattr %p ATTR_FILE ... hrm!\n", inode);
+
+	if (dirtied) {
+		inode_dirty_flags = __ceph_mark_dirty_caps(ci, dirtied);
+		inode->i_ctime = CURRENT_TIME;
+	}
+
+	release &= issued;
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (inode_dirty_flags)
+		__mark_inode_dirty(inode, inode_dirty_flags);
+
+	if (ia_valid & ATTR_MODE) {
+		err = posix_acl_chmod(inode, attr->ia_mode);
+		if (err)
+			goto out_put;
+	}
+
+	if (mask) {
+		req->r_inode = inode;
+		ihold(inode);
+		req->r_inode_drop = release;
+		req->r_args.setattr.mask = cpu_to_le32(mask);
+		req->r_num_caps = 1;
+		err = ceph_mdsc_do_request(mdsc, NULL, req);
+	}
+	dout("setattr %p result=%d (%s locally, %d remote)\n", inode, err,
+	     ceph_cap_string(dirtied), mask);
+
+	ceph_mdsc_put_request(req);
+	if (mask & CEPH_SETATTR_SIZE)
+		__ceph_do_pending_vmtruncate(inode);
+	return err;
+out_put:
+	ceph_mdsc_put_request(req);
+	return err;
+}
+
+/*
+ * Verify that we have a lease on the given mask.  If not,
+ * do a getattr against an mds.
+ */
+int __ceph_do_getattr(struct inode *inode, struct page *locked_page,
+		      int mask, bool force)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req;
+	int err;
+
+	if (ceph_snap(inode) == CEPH_SNAPDIR) {
+		dout("do_getattr inode %p SNAPDIR\n", inode);
+		return 0;
+	}
+
+	dout("do_getattr inode %p mask %s mode 0%o\n",
+	     inode, ceph_cap_string(mask), inode->i_mode);
+	if (!force && ceph_caps_issued_mask(ceph_inode(inode), mask, 1))
+		return 0;
+
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	req->r_inode = inode;
+	ihold(inode);
+	req->r_num_caps = 1;
+	req->r_args.getattr.mask = cpu_to_le32(mask);
+	req->r_locked_page = locked_page;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	if (locked_page && err == 0) {
+		u64 inline_version = req->r_reply_info.targeti.inline_version;
+		if (inline_version == 0) {
+			/* the reply is supposed to contain inline data */
+			err = -EINVAL;
+		} else if (inline_version == CEPH_INLINE_NONE) {
+			err = -ENODATA;
+		} else {
+			err = req->r_reply_info.targeti.inline_len;
+		}
+	}
+	ceph_mdsc_put_request(req);
+	dout("do_getattr result=%d\n", err);
+	return err;
+}
+
+
+/*
+ * Check inode permissions.  We verify we have a valid value for
+ * the AUTH cap, then call the generic handler.
+ */
+int ceph_permission(struct inode *inode, int mask)
+{
+	int err;
+
+	if (mask & MAY_NOT_BLOCK)
+		return -ECHILD;
+
+	err = ceph_do_getattr(inode, CEPH_CAP_AUTH_SHARED, false);
+
+	if (!err)
+		err = generic_permission(inode, mask);
+	return err;
+}
+
+/*
+ * Get all attributes.  Hopefully somedata we'll have a statlite()
+ * and can limit the fields we require to be accurate.
+ */
+int ceph_getattr(struct vfsmount *mnt, struct dentry *dentry,
+		 struct kstat *stat)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int err;
+
+	err = ceph_do_getattr(inode, CEPH_STAT_CAP_INODE_ALL, false);
+	if (!err) {
+		generic_fillattr(inode, stat);
+		stat->ino = ceph_translate_ino(inode->i_sb, inode->i_ino);
+		if (ceph_snap(inode) != CEPH_NOSNAP)
+			stat->dev = ceph_snap(inode);
+		else
+			stat->dev = 0;
+		if (S_ISDIR(inode->i_mode)) {
+			if (ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb),
+						RBYTES))
+				stat->size = ci->i_rbytes;
+			else
+				stat->size = ci->i_files + ci->i_subdirs;
+			stat->blocks = 0;
+			stat->blksize = 65536;
+		}
+	}
+	return err;
+}
diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
new file mode 100644
index 000000000..f851d8d70
--- /dev/null
+++ b/fs/ceph/ioctl.c
@@ -0,0 +1,295 @@
+#include <linux/ceph/ceph_debug.h>
+#include <linux/in.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include "ioctl.h"
+
+
+/*
+ * ioctls
+ */
+
+/*
+ * get and set the file layout
+ */
+static long ceph_ioctl_get_layout(struct file *file, void __user *arg)
+{
+	struct ceph_inode_info *ci = ceph_inode(file_inode(file));
+	struct ceph_ioctl_layout l;
+	int err;
+
+	err = ceph_do_getattr(file_inode(file), CEPH_STAT_CAP_LAYOUT, false);
+	if (!err) {
+		l.stripe_unit = ceph_file_layout_su(ci->i_layout);
+		l.stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
+		l.object_size = ceph_file_layout_object_size(ci->i_layout);
+		l.data_pool = le32_to_cpu(ci->i_layout.fl_pg_pool);
+		l.preferred_osd = (s32)-1;
+		if (copy_to_user(arg, &l, sizeof(l)))
+			return -EFAULT;
+	}
+
+	return err;
+}
+
+static long __validate_layout(struct ceph_mds_client *mdsc,
+			      struct ceph_ioctl_layout *l)
+{
+	int i, err;
+
+	/* validate striping parameters */
+	if ((l->object_size & ~PAGE_MASK) ||
+	    (l->stripe_unit & ~PAGE_MASK) ||
+	    ((unsigned)l->stripe_unit != 0 &&
+	     ((unsigned)l->object_size % (unsigned)l->stripe_unit)))
+		return -EINVAL;
+
+	/* make sure it's a valid data pool */
+	mutex_lock(&mdsc->mutex);
+	err = -EINVAL;
+	for (i = 0; i < mdsc->mdsmap->m_num_data_pg_pools; i++)
+		if (mdsc->mdsmap->m_data_pg_pools[i] == l->data_pool) {
+			err = 0;
+			break;
+		}
+	mutex_unlock(&mdsc->mutex);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static long ceph_ioctl_set_layout(struct file *file, void __user *arg)
+{
+	struct inode *inode = file_inode(file);
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+	struct ceph_mds_request *req;
+	struct ceph_ioctl_layout l;
+	struct ceph_inode_info *ci = ceph_inode(file_inode(file));
+	struct ceph_ioctl_layout nl;
+	int err;
+
+	if (copy_from_user(&l, arg, sizeof(l)))
+		return -EFAULT;
+
+	/* validate changed params against current layout */
+	err = ceph_do_getattr(file_inode(file), CEPH_STAT_CAP_LAYOUT, false);
+	if (err)
+		return err;
+
+	memset(&nl, 0, sizeof(nl));
+	if (l.stripe_count)
+		nl.stripe_count = l.stripe_count;
+	else
+		nl.stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
+	if (l.stripe_unit)
+		nl.stripe_unit = l.stripe_unit;
+	else
+		nl.stripe_unit = ceph_file_layout_su(ci->i_layout);
+	if (l.object_size)
+		nl.object_size = l.object_size;
+	else
+		nl.object_size = ceph_file_layout_object_size(ci->i_layout);
+	if (l.data_pool)
+		nl.data_pool = l.data_pool;
+	else
+		nl.data_pool = ceph_file_layout_pg_pool(ci->i_layout);
+
+	/* this is obsolete, and always -1 */
+	nl.preferred_osd = le64_to_cpu(-1);
+
+	err = __validate_layout(mdsc, &nl);
+	if (err)
+		return err;
+
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETLAYOUT,
+				       USE_AUTH_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	req->r_inode = inode;
+	ihold(inode);
+	req->r_num_caps = 1;
+
+	req->r_inode_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_EXCL;
+
+	req->r_args.setlayout.layout.fl_stripe_unit =
+		cpu_to_le32(l.stripe_unit);
+	req->r_args.setlayout.layout.fl_stripe_count =
+		cpu_to_le32(l.stripe_count);
+	req->r_args.setlayout.layout.fl_object_size =
+		cpu_to_le32(l.object_size);
+	req->r_args.setlayout.layout.fl_pg_pool = cpu_to_le32(l.data_pool);
+
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	ceph_mdsc_put_request(req);
+	return err;
+}
+
+/*
+ * Set a layout policy on a directory inode. All items in the tree
+ * rooted at this inode will inherit this layout on creation,
+ * (It doesn't apply retroactively )
+ * unless a subdirectory has its own layout policy.
+ */
+static long ceph_ioctl_set_layout_policy (struct file *file, void __user *arg)
+{
+	struct inode *inode = file_inode(file);
+	struct ceph_mds_request *req;
+	struct ceph_ioctl_layout l;
+	int err;
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+
+	/* copy and validate */
+	if (copy_from_user(&l, arg, sizeof(l)))
+		return -EFAULT;
+
+	err = __validate_layout(mdsc, &l);
+	if (err)
+		return err;
+
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETDIRLAYOUT,
+				       USE_AUTH_MDS);
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	req->r_inode = inode;
+	ihold(inode);
+	req->r_num_caps = 1;
+
+	req->r_args.setlayout.layout.fl_stripe_unit =
+			cpu_to_le32(l.stripe_unit);
+	req->r_args.setlayout.layout.fl_stripe_count =
+			cpu_to_le32(l.stripe_count);
+	req->r_args.setlayout.layout.fl_object_size =
+			cpu_to_le32(l.object_size);
+	req->r_args.setlayout.layout.fl_pg_pool =
+			cpu_to_le32(l.data_pool);
+
+	err = ceph_mdsc_do_request(mdsc, inode, req);
+	ceph_mdsc_put_request(req);
+	return err;
+}
+
+/*
+ * Return object name, size/offset information, and location (OSD
+ * number, network address) for a given file offset.
+ */
+static long ceph_ioctl_get_dataloc(struct file *file, void __user *arg)
+{
+	struct ceph_ioctl_dataloc dl;
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_osd_client *osdc =
+		&ceph_sb_to_client(inode->i_sb)->client->osdc;
+	struct ceph_object_locator oloc;
+	struct ceph_object_id oid;
+	u64 len = 1, olen;
+	u64 tmp;
+	struct ceph_pg pgid;
+	int r;
+
+	/* copy and validate */
+	if (copy_from_user(&dl, arg, sizeof(dl)))
+		return -EFAULT;
+
+	down_read(&osdc->map_sem);
+	r = ceph_calc_file_object_mapping(&ci->i_layout, dl.file_offset, len,
+					  &dl.object_no, &dl.object_offset,
+					  &olen);
+	if (r < 0) {
+		up_read(&osdc->map_sem);
+		return -EIO;
+	}
+	dl.file_offset -= dl.object_offset;
+	dl.object_size = ceph_file_layout_object_size(ci->i_layout);
+	dl.block_size = ceph_file_layout_su(ci->i_layout);
+
+	/* block_offset = object_offset % block_size */
+	tmp = dl.object_offset;
+	dl.block_offset = do_div(tmp, dl.block_size);
+
+	snprintf(dl.object_name, sizeof(dl.object_name), "%llx.%08llx",
+		 ceph_ino(inode), dl.object_no);
+
+	oloc.pool = ceph_file_layout_pg_pool(ci->i_layout);
+	ceph_oid_set_name(&oid, dl.object_name);
+
+	r = ceph_oloc_oid_to_pg(osdc->osdmap, &oloc, &oid, &pgid);
+	if (r < 0) {
+		up_read(&osdc->map_sem);
+		return r;
+	}
+
+	dl.osd = ceph_calc_pg_primary(osdc->osdmap, pgid);
+	if (dl.osd >= 0) {
+		struct ceph_entity_addr *a =
+			ceph_osd_addr(osdc->osdmap, dl.osd);
+		if (a)
+			memcpy(&dl.osd_addr, &a->in_addr, sizeof(dl.osd_addr));
+	} else {
+		memset(&dl.osd_addr, 0, sizeof(dl.osd_addr));
+	}
+	up_read(&osdc->map_sem);
+
+	/* send result back to user */
+	if (copy_to_user(arg, &dl, sizeof(dl)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ceph_ioctl_lazyio(struct file *file)
+{
+	struct ceph_file_info *fi = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	if ((fi->fmode & CEPH_FILE_MODE_LAZY) == 0) {
+		spin_lock(&ci->i_ceph_lock);
+		ci->i_nr_by_mode[fi->fmode]--;
+		fi->fmode |= CEPH_FILE_MODE_LAZY;
+		ci->i_nr_by_mode[fi->fmode]++;
+		spin_unlock(&ci->i_ceph_lock);
+		dout("ioctl_layzio: file %p marked lazy\n", file);
+
+		ceph_check_caps(ci, 0, NULL);
+	} else {
+		dout("ioctl_layzio: file %p already lazy\n", file);
+	}
+	return 0;
+}
+
+static long ceph_ioctl_syncio(struct file *file)
+{
+	struct ceph_file_info *fi = file->private_data;
+
+	fi->flags |= CEPH_F_SYNC;
+	return 0;
+}
+
+long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	dout("ioctl file %p cmd %u arg %lu\n", file, cmd, arg);
+	switch (cmd) {
+	case CEPH_IOC_GET_LAYOUT:
+		return ceph_ioctl_get_layout(file, (void __user *)arg);
+
+	case CEPH_IOC_SET_LAYOUT:
+		return ceph_ioctl_set_layout(file, (void __user *)arg);
+
+	case CEPH_IOC_SET_LAYOUT_POLICY:
+		return ceph_ioctl_set_layout_policy(file, (void __user *)arg);
+
+	case CEPH_IOC_GET_DATALOC:
+		return ceph_ioctl_get_dataloc(file, (void __user *)arg);
+
+	case CEPH_IOC_LAZYIO:
+		return ceph_ioctl_lazyio(file);
+
+	case CEPH_IOC_SYNCIO:
+		return ceph_ioctl_syncio(file);
+	}
+
+	return -ENOTTY;
+}
diff --git a/fs/ceph/ioctl.h b/fs/ceph/ioctl.h
new file mode 100644
index 000000000..c77028afb
--- /dev/null
+++ b/fs/ceph/ioctl.h
@@ -0,0 +1,100 @@
+#ifndef FS_CEPH_IOCTL_H
+#define FS_CEPH_IOCTL_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define CEPH_IOCTL_MAGIC 0x97
+
+/*
+ * CEPH_IOC_GET_LAYOUT - get file layout or dir layout policy
+ * CEPH_IOC_SET_LAYOUT - set file layout
+ * CEPH_IOC_SET_LAYOUT_POLICY - set dir layout policy
+ *
+ * The file layout specifies how file data is striped over objects in
+ * the distributed object store, which object pool they belong to (if
+ * it differs from the default), and an optional 'preferred osd' to
+ * store them on.
+ *
+ * Files get a new layout based on the policy set on the containing
+ * directory or one of its ancestors.  The GET_LAYOUT ioctl will let
+ * you examine the layout for a file or the policy on a directory.
+ *
+ * SET_LAYOUT will let you set a layout on a newly created file.  This
+ * only works immediately after the file is created and before any
+ * data is written to it.
+ *
+ * SET_LAYOUT_POLICY will let you set a layout policy (default layout)
+ * on a directory that will apply to any new files created in that
+ * directory (or any child directory that doesn't specify a layout of
+ * its own).
+ */
+
+/* use u64 to align sanely on all archs */
+struct ceph_ioctl_layout {
+	__u64 stripe_unit, stripe_count, object_size;
+	__u64 data_pool;
+
+	/* obsolete.  new values ignored, always return -1 */
+	__s64 preferred_osd;
+};
+
+#define CEPH_IOC_GET_LAYOUT _IOR(CEPH_IOCTL_MAGIC, 1,		\
+				   struct ceph_ioctl_layout)
+#define CEPH_IOC_SET_LAYOUT _IOW(CEPH_IOCTL_MAGIC, 2,		\
+				   struct ceph_ioctl_layout)
+#define CEPH_IOC_SET_LAYOUT_POLICY _IOW(CEPH_IOCTL_MAGIC, 5,	\
+				   struct ceph_ioctl_layout)
+
+/*
+ * CEPH_IOC_GET_DATALOC - get location of file data in the cluster
+ *
+ * Extract identity, address of the OSD and object storing a given
+ * file offset.
+ */
+struct ceph_ioctl_dataloc {
+	__u64 file_offset;           /* in+out: file offset */
+	__u64 object_offset;         /* out: offset in object */
+	__u64 object_no;             /* out: object # */
+	__u64 object_size;           /* out: object size */
+	char object_name[64];        /* out: object name */
+	__u64 block_offset;          /* out: offset in block */
+	__u64 block_size;            /* out: block length */
+	__s64 osd;                   /* out: osd # */
+	struct sockaddr_storage osd_addr; /* out: osd address */
+};
+
+#define CEPH_IOC_GET_DATALOC _IOWR(CEPH_IOCTL_MAGIC, 3,	\
+				   struct ceph_ioctl_dataloc)
+
+/*
+ * CEPH_IOC_LAZYIO - relax consistency
+ *
+ * Normally Ceph switches to synchronous IO when multiple clients have
+ * the file open (and or more for write).  Reads and writes bypass the
+ * page cache and go directly to the OSD.  Setting this flag on a file
+ * descriptor will allow buffered IO for this file in cases where the
+ * application knows it won't interfere with other nodes (or doesn't
+ * care).
+ */
+#define CEPH_IOC_LAZYIO _IO(CEPH_IOCTL_MAGIC, 4)
+
+/*
+ * CEPH_IOC_SYNCIO - force synchronous IO
+ *
+ * This ioctl sets a file flag that forces the synchronous IO that
+ * bypasses the page cache, even if it is not necessary.  This is
+ * essentially the opposite behavior of IOC_LAZYIO.  This forces the
+ * same read/write path as a file opened by multiple clients when one
+ * or more of those clients is opened for write.
+ *
+ * Note that this type of sync IO takes a different path than a file
+ * opened with O_SYNC/D_SYNC (writes hit the page cache and are
+ * immediately flushed on page boundaries).  It is very similar to
+ * O_DIRECT (writes bypass the page cache) excep that O_DIRECT writes
+ * are not copied (user page must remain stable) and O_DIRECT writes
+ * have alignment restrictions (on the buffer and file offset).
+ */
+#define CEPH_IOC_SYNCIO _IO(CEPH_IOCTL_MAGIC, 5)
+
+#endif
diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
new file mode 100644
index 000000000..4347039ec
--- /dev/null
+++ b/fs/ceph/locks.c
@@ -0,0 +1,381 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/random.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include <linux/ceph/pagelist.h>
+
+static u64 lock_secret;
+static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
+                                         struct ceph_mds_request *req);
+
+static inline u64 secure_addr(void *addr)
+{
+	u64 v = lock_secret ^ (u64)(unsigned long)addr;
+	/*
+	 * Set the most significant bit, so that MDS knows the 'owner'
+	 * is sufficient to identify the owner of lock. (old code uses
+	 * both 'owner' and 'pid')
+	 */
+	v |= (1ULL << 63);
+	return v;
+}
+
+void __init ceph_flock_init(void)
+{
+	get_random_bytes(&lock_secret, sizeof(lock_secret));
+}
+
+/**
+ * Implement fcntl and flock locking functions.
+ */
+static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,
+			     int cmd, u8 wait, struct file_lock *fl)
+{
+	struct inode *inode = file_inode(file);
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+	struct ceph_mds_request *req;
+	int err;
+	u64 length = 0;
+	u64 owner;
+
+	if (operation != CEPH_MDS_OP_SETFILELOCK || cmd == CEPH_LOCK_UNLOCK)
+		wait = 0;
+
+	req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	req->r_inode = inode;
+	ihold(inode);
+	req->r_num_caps = 1;
+
+	/* mds requires start and length rather than start and end */
+	if (LLONG_MAX == fl->fl_end)
+		length = 0;
+	else
+		length = fl->fl_end - fl->fl_start + 1;
+
+	owner = secure_addr(fl->fl_owner);
+
+	dout("ceph_lock_message: rule: %d, op: %d, owner: %llx, pid: %llu, "
+	     "start: %llu, length: %llu, wait: %d, type: %d", (int)lock_type,
+	     (int)operation, owner, (u64)fl->fl_pid, fl->fl_start, length,
+	     wait, fl->fl_type);
+
+	req->r_args.filelock_change.rule = lock_type;
+	req->r_args.filelock_change.type = cmd;
+	req->r_args.filelock_change.owner = cpu_to_le64(owner);
+	req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid);
+	req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start);
+	req->r_args.filelock_change.length = cpu_to_le64(length);
+	req->r_args.filelock_change.wait = wait;
+
+	if (wait)
+		req->r_wait_for_completion = ceph_lock_wait_for_completion;
+
+	err = ceph_mdsc_do_request(mdsc, inode, req);
+
+	if (operation == CEPH_MDS_OP_GETFILELOCK) {
+		fl->fl_pid = le64_to_cpu(req->r_reply_info.filelock_reply->pid);
+		if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
+			fl->fl_type = F_RDLCK;
+		else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type)
+			fl->fl_type = F_WRLCK;
+		else
+			fl->fl_type = F_UNLCK;
+
+		fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start);
+		length = le64_to_cpu(req->r_reply_info.filelock_reply->start) +
+						 le64_to_cpu(req->r_reply_info.filelock_reply->length);
+		if (length >= 1)
+			fl->fl_end = length -1;
+		else
+			fl->fl_end = 0;
+
+	}
+	ceph_mdsc_put_request(req);
+	dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
+	     "length: %llu, wait: %d, type: %d, err code %d", (int)lock_type,
+	     (int)operation, (u64)fl->fl_pid, fl->fl_start,
+	     length, wait, fl->fl_type, err);
+	return err;
+}
+
+static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
+                                         struct ceph_mds_request *req)
+{
+	struct ceph_mds_request *intr_req;
+	struct inode *inode = req->r_inode;
+	int err, lock_type;
+
+	BUG_ON(req->r_op != CEPH_MDS_OP_SETFILELOCK);
+	if (req->r_args.filelock_change.rule == CEPH_LOCK_FCNTL)
+		lock_type = CEPH_LOCK_FCNTL_INTR;
+	else if (req->r_args.filelock_change.rule == CEPH_LOCK_FLOCK)
+		lock_type = CEPH_LOCK_FLOCK_INTR;
+	else
+		BUG_ON(1);
+	BUG_ON(req->r_args.filelock_change.type == CEPH_LOCK_UNLOCK);
+
+	err = wait_for_completion_interruptible(&req->r_completion);
+	if (!err)
+		return 0;
+
+	dout("ceph_lock_wait_for_completion: request %llu was interrupted\n",
+	     req->r_tid);
+
+	intr_req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETFILELOCK,
+					    USE_AUTH_MDS);
+	if (IS_ERR(intr_req))
+		return PTR_ERR(intr_req);
+
+	intr_req->r_inode = inode;
+	ihold(inode);
+	intr_req->r_num_caps = 1;
+
+	intr_req->r_args.filelock_change = req->r_args.filelock_change;
+	intr_req->r_args.filelock_change.rule = lock_type;
+	intr_req->r_args.filelock_change.type = CEPH_LOCK_UNLOCK;
+
+	err = ceph_mdsc_do_request(mdsc, inode, intr_req);
+	ceph_mdsc_put_request(intr_req);
+
+	if (err && err != -ERESTARTSYS)
+		return err;
+
+	wait_for_completion(&req->r_completion);
+	return 0;
+}
+
+/**
+ * Attempt to set an fcntl lock.
+ * For now, this just goes away to the server. Later it may be more awesome.
+ */
+int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
+{
+	u8 lock_cmd;
+	int err;
+	u8 wait = 0;
+	u16 op = CEPH_MDS_OP_SETFILELOCK;
+
+	if (!(fl->fl_flags & FL_POSIX))
+		return -ENOLCK;
+	/* No mandatory locks */
+	if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
+		return -ENOLCK;
+
+	dout("ceph_lock, fl_owner: %p", fl->fl_owner);
+
+	/* set wait bit as appropriate, then make command as Ceph expects it*/
+	if (IS_GETLK(cmd))
+		op = CEPH_MDS_OP_GETFILELOCK;
+	else if (IS_SETLKW(cmd))
+		wait = 1;
+
+	if (F_RDLCK == fl->fl_type)
+		lock_cmd = CEPH_LOCK_SHARED;
+	else if (F_WRLCK == fl->fl_type)
+		lock_cmd = CEPH_LOCK_EXCL;
+	else
+		lock_cmd = CEPH_LOCK_UNLOCK;
+
+	err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl);
+	if (!err) {
+		if (op != CEPH_MDS_OP_GETFILELOCK) {
+			dout("mds locked, locking locally");
+			err = posix_lock_file(file, fl, NULL);
+			if (err && (CEPH_MDS_OP_SETFILELOCK == op)) {
+				/* undo! This should only happen if
+				 * the kernel detects local
+				 * deadlock. */
+				ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
+						  CEPH_LOCK_UNLOCK, 0, fl);
+				dout("got %d on posix_lock_file, undid lock",
+				     err);
+			}
+		}
+	}
+	return err;
+}
+
+int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
+{
+	u8 lock_cmd;
+	int err;
+	u8 wait = 0;
+
+	if (!(fl->fl_flags & FL_FLOCK))
+		return -ENOLCK;
+	/* No mandatory locks */
+	if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
+		return -ENOLCK;
+
+	dout("ceph_flock, fl_file: %p", fl->fl_file);
+
+	if (IS_SETLKW(cmd))
+		wait = 1;
+
+	if (F_RDLCK == fl->fl_type)
+		lock_cmd = CEPH_LOCK_SHARED;
+	else if (F_WRLCK == fl->fl_type)
+		lock_cmd = CEPH_LOCK_EXCL;
+	else
+		lock_cmd = CEPH_LOCK_UNLOCK;
+
+	err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
+				file, lock_cmd, wait, fl);
+	if (!err) {
+		err = flock_lock_file_wait(file, fl);
+		if (err) {
+			ceph_lock_message(CEPH_LOCK_FLOCK,
+					  CEPH_MDS_OP_SETFILELOCK,
+					  file, CEPH_LOCK_UNLOCK, 0, fl);
+			dout("got %d on flock_lock_file_wait, undid lock", err);
+		}
+	}
+	return err;
+}
+
+/*
+ * Fills in the passed counter variables, so you can prepare pagelist metadata
+ * before calling ceph_encode_locks.
+ */
+void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
+{
+	struct file_lock *lock;
+	struct file_lock_context *ctx;
+
+	*fcntl_count = 0;
+	*flock_count = 0;
+
+	ctx = inode->i_flctx;
+	if (ctx) {
+		spin_lock(&ctx->flc_lock);
+		list_for_each_entry(lock, &ctx->flc_posix, fl_list)
+			++(*fcntl_count);
+		list_for_each_entry(lock, &ctx->flc_flock, fl_list)
+			++(*flock_count);
+		spin_unlock(&ctx->flc_lock);
+	}
+	dout("counted %d flock locks and %d fcntl locks",
+	     *flock_count, *fcntl_count);
+}
+
+/**
+ * Encode the flock and fcntl locks for the given inode into the ceph_filelock
+ * array. Must be called with inode->i_lock already held.
+ * If we encounter more of a specific lock type than expected, return -ENOSPC.
+ */
+int ceph_encode_locks_to_buffer(struct inode *inode,
+				struct ceph_filelock *flocks,
+				int num_fcntl_locks, int num_flock_locks)
+{
+	struct file_lock *lock;
+	struct file_lock_context *ctx = inode->i_flctx;
+	int err = 0;
+	int seen_fcntl = 0;
+	int seen_flock = 0;
+	int l = 0;
+
+	dout("encoding %d flock and %d fcntl locks", num_flock_locks,
+	     num_fcntl_locks);
+
+	if (!ctx)
+		return 0;
+
+	spin_lock(&ctx->flc_lock);
+	list_for_each_entry(lock, &ctx->flc_flock, fl_list) {
+		++seen_fcntl;
+		if (seen_fcntl > num_fcntl_locks) {
+			err = -ENOSPC;
+			goto fail;
+		}
+		err = lock_to_ceph_filelock(lock, &flocks[l]);
+		if (err)
+			goto fail;
+		++l;
+	}
+	list_for_each_entry(lock, &ctx->flc_flock, fl_list) {
+		++seen_flock;
+		if (seen_flock > num_flock_locks) {
+			err = -ENOSPC;
+			goto fail;
+		}
+		err = lock_to_ceph_filelock(lock, &flocks[l]);
+		if (err)
+			goto fail;
+		++l;
+	}
+fail:
+	spin_unlock(&ctx->flc_lock);
+	return err;
+}
+
+/**
+ * Copy the encoded flock and fcntl locks into the pagelist.
+ * Format is: #fcntl locks, sequential fcntl locks, #flock locks,
+ * sequential flock locks.
+ * Returns zero on success.
+ */
+int ceph_locks_to_pagelist(struct ceph_filelock *flocks,
+			   struct ceph_pagelist *pagelist,
+			   int num_fcntl_locks, int num_flock_locks)
+{
+	int err = 0;
+	__le32 nlocks;
+
+	nlocks = cpu_to_le32(num_fcntl_locks);
+	err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
+	if (err)
+		goto out_fail;
+
+	err = ceph_pagelist_append(pagelist, flocks,
+				   num_fcntl_locks * sizeof(*flocks));
+	if (err)
+		goto out_fail;
+
+	nlocks = cpu_to_le32(num_flock_locks);
+	err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
+	if (err)
+		goto out_fail;
+
+	err = ceph_pagelist_append(pagelist,
+				   &flocks[num_fcntl_locks],
+				   num_flock_locks * sizeof(*flocks));
+out_fail:
+	return err;
+}
+
+/*
+ * Given a pointer to a lock, convert it to a ceph filelock
+ */
+int lock_to_ceph_filelock(struct file_lock *lock,
+			  struct ceph_filelock *cephlock)
+{
+	int err = 0;
+	cephlock->start = cpu_to_le64(lock->fl_start);
+	cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
+	cephlock->client = cpu_to_le64(0);
+	cephlock->pid = cpu_to_le64((u64)lock->fl_pid);
+	cephlock->owner = cpu_to_le64(secure_addr(lock->fl_owner));
+
+	switch (lock->fl_type) {
+	case F_RDLCK:
+		cephlock->type = CEPH_LOCK_SHARED;
+		break;
+	case F_WRLCK:
+		cephlock->type = CEPH_LOCK_EXCL;
+		break;
+	case F_UNLCK:
+		cephlock->type = CEPH_LOCK_UNLOCK;
+		break;
+	default:
+		dout("Have unknown lock type %d", lock->fl_type);
+		err = -EINVAL;
+	}
+
+	return err;
+}
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
new file mode 100644
index 000000000..84f37f34f
--- /dev/null
+++ b/fs/ceph/mds_client.c
@@ -0,0 +1,3871 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/fs.h>
+#include <linux/wait.h>
+#include <linux/slab.h>
+#include <linux/gfp.h>
+#include <linux/sched.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/utsname.h>
+
+#include "super.h"
+#include "mds_client.h"
+
+#include <linux/ceph/ceph_features.h>
+#include <linux/ceph/messenger.h>
+#include <linux/ceph/decode.h>
+#include <linux/ceph/pagelist.h>
+#include <linux/ceph/auth.h>
+#include <linux/ceph/debugfs.h>
+
+/*
+ * A cluster of MDS (metadata server) daemons is responsible for
+ * managing the file system namespace (the directory hierarchy and
+ * inodes) and for coordinating shared access to storage.  Metadata is
+ * partitioning hierarchically across a number of servers, and that
+ * partition varies over time as the cluster adjusts the distribution
+ * in order to balance load.
+ *
+ * The MDS client is primarily responsible to managing synchronous
+ * metadata requests for operations like open, unlink, and so forth.
+ * If there is a MDS failure, we find out about it when we (possibly
+ * request and) receive a new MDS map, and can resubmit affected
+ * requests.
+ *
+ * For the most part, though, we take advantage of a lossless
+ * communications channel to the MDS, and do not need to worry about
+ * timing out or resubmitting requests.
+ *
+ * We maintain a stateful "session" with each MDS we interact with.
+ * Within each session, we sent periodic heartbeat messages to ensure
+ * any capabilities or leases we have been issues remain valid.  If
+ * the session times out and goes stale, our leases and capabilities
+ * are no longer valid.
+ */
+
+struct ceph_reconnect_state {
+	int nr_caps;
+	struct ceph_pagelist *pagelist;
+	bool flock;
+};
+
+static void __wake_requests(struct ceph_mds_client *mdsc,
+			    struct list_head *head);
+
+static const struct ceph_connection_operations mds_con_ops;
+
+
+/*
+ * mds reply parsing
+ */
+
+/*
+ * parse individual inode info
+ */
+static int parse_reply_info_in(void **p, void *end,
+			       struct ceph_mds_reply_info_in *info,
+			       u64 features)
+{
+	int err = -EIO;
+
+	info->in = *p;
+	*p += sizeof(struct ceph_mds_reply_inode) +
+		sizeof(*info->in->fragtree.splits) *
+		le32_to_cpu(info->in->fragtree.nsplits);
+
+	ceph_decode_32_safe(p, end, info->symlink_len, bad);
+	ceph_decode_need(p, end, info->symlink_len, bad);
+	info->symlink = *p;
+	*p += info->symlink_len;
+
+	if (features & CEPH_FEATURE_DIRLAYOUTHASH)
+		ceph_decode_copy_safe(p, end, &info->dir_layout,
+				      sizeof(info->dir_layout), bad);
+	else
+		memset(&info->dir_layout, 0, sizeof(info->dir_layout));
+
+	ceph_decode_32_safe(p, end, info->xattr_len, bad);
+	ceph_decode_need(p, end, info->xattr_len, bad);
+	info->xattr_data = *p;
+	*p += info->xattr_len;
+
+	if (features & CEPH_FEATURE_MDS_INLINE_DATA) {
+		ceph_decode_64_safe(p, end, info->inline_version, bad);
+		ceph_decode_32_safe(p, end, info->inline_len, bad);
+		ceph_decode_need(p, end, info->inline_len, bad);
+		info->inline_data = *p;
+		*p += info->inline_len;
+	} else
+		info->inline_version = CEPH_INLINE_NONE;
+
+	return 0;
+bad:
+	return err;
+}
+
+/*
+ * parse a normal reply, which may contain a (dir+)dentry and/or a
+ * target inode.
+ */
+static int parse_reply_info_trace(void **p, void *end,
+				  struct ceph_mds_reply_info_parsed *info,
+				  u64 features)
+{
+	int err;
+
+	if (info->head->is_dentry) {
+		err = parse_reply_info_in(p, end, &info->diri, features);
+		if (err < 0)
+			goto out_bad;
+
+		if (unlikely(*p + sizeof(*info->dirfrag) > end))
+			goto bad;
+		info->dirfrag = *p;
+		*p += sizeof(*info->dirfrag) +
+			sizeof(u32)*le32_to_cpu(info->dirfrag->ndist);
+		if (unlikely(*p > end))
+			goto bad;
+
+		ceph_decode_32_safe(p, end, info->dname_len, bad);
+		ceph_decode_need(p, end, info->dname_len, bad);
+		info->dname = *p;
+		*p += info->dname_len;
+		info->dlease = *p;
+		*p += sizeof(*info->dlease);
+	}
+
+	if (info->head->is_target) {
+		err = parse_reply_info_in(p, end, &info->targeti, features);
+		if (err < 0)
+			goto out_bad;
+	}
+
+	if (unlikely(*p != end))
+		goto bad;
+	return 0;
+
+bad:
+	err = -EIO;
+out_bad:
+	pr_err("problem parsing mds trace %d\n", err);
+	return err;
+}
+
+/*
+ * parse readdir results
+ */
+static int parse_reply_info_dir(void **p, void *end,
+				struct ceph_mds_reply_info_parsed *info,
+				u64 features)
+{
+	u32 num, i = 0;
+	int err;
+
+	info->dir_dir = *p;
+	if (*p + sizeof(*info->dir_dir) > end)
+		goto bad;
+	*p += sizeof(*info->dir_dir) +
+		sizeof(u32)*le32_to_cpu(info->dir_dir->ndist);
+	if (*p > end)
+		goto bad;
+
+	ceph_decode_need(p, end, sizeof(num) + 2, bad);
+	num = ceph_decode_32(p);
+	info->dir_end = ceph_decode_8(p);
+	info->dir_complete = ceph_decode_8(p);
+	if (num == 0)
+		goto done;
+
+	BUG_ON(!info->dir_in);
+	info->dir_dname = (void *)(info->dir_in + num);
+	info->dir_dname_len = (void *)(info->dir_dname + num);
+	info->dir_dlease = (void *)(info->dir_dname_len + num);
+	if ((unsigned long)(info->dir_dlease + num) >
+	    (unsigned long)info->dir_in + info->dir_buf_size) {
+		pr_err("dir contents are larger than expected\n");
+		WARN_ON(1);
+		goto bad;
+	}
+
+	info->dir_nr = num;
+	while (num) {
+		/* dentry */
+		ceph_decode_need(p, end, sizeof(u32)*2, bad);
+		info->dir_dname_len[i] = ceph_decode_32(p);
+		ceph_decode_need(p, end, info->dir_dname_len[i], bad);
+		info->dir_dname[i] = *p;
+		*p += info->dir_dname_len[i];
+		dout("parsed dir dname '%.*s'\n", info->dir_dname_len[i],
+		     info->dir_dname[i]);
+		info->dir_dlease[i] = *p;
+		*p += sizeof(struct ceph_mds_reply_lease);
+
+		/* inode */
+		err = parse_reply_info_in(p, end, &info->dir_in[i], features);
+		if (err < 0)
+			goto out_bad;
+		i++;
+		num--;
+	}
+
+done:
+	if (*p != end)
+		goto bad;
+	return 0;
+
+bad:
+	err = -EIO;
+out_bad:
+	pr_err("problem parsing dir contents %d\n", err);
+	return err;
+}
+
+/*
+ * parse fcntl F_GETLK results
+ */
+static int parse_reply_info_filelock(void **p, void *end,
+				     struct ceph_mds_reply_info_parsed *info,
+				     u64 features)
+{
+	if (*p + sizeof(*info->filelock_reply) > end)
+		goto bad;
+
+	info->filelock_reply = *p;
+	*p += sizeof(*info->filelock_reply);
+
+	if (unlikely(*p != end))
+		goto bad;
+	return 0;
+
+bad:
+	return -EIO;
+}
+
+/*
+ * parse create results
+ */
+static int parse_reply_info_create(void **p, void *end,
+				  struct ceph_mds_reply_info_parsed *info,
+				  u64 features)
+{
+	if (features & CEPH_FEATURE_REPLY_CREATE_INODE) {
+		if (*p == end) {
+			info->has_create_ino = false;
+		} else {
+			info->has_create_ino = true;
+			info->ino = ceph_decode_64(p);
+		}
+	}
+
+	if (unlikely(*p != end))
+		goto bad;
+	return 0;
+
+bad:
+	return -EIO;
+}
+
+/*
+ * parse extra results
+ */
+static int parse_reply_info_extra(void **p, void *end,
+				  struct ceph_mds_reply_info_parsed *info,
+				  u64 features)
+{
+	if (info->head->op == CEPH_MDS_OP_GETFILELOCK)
+		return parse_reply_info_filelock(p, end, info, features);
+	else if (info->head->op == CEPH_MDS_OP_READDIR ||
+		 info->head->op == CEPH_MDS_OP_LSSNAP)
+		return parse_reply_info_dir(p, end, info, features);
+	else if (info->head->op == CEPH_MDS_OP_CREATE)
+		return parse_reply_info_create(p, end, info, features);
+	else
+		return -EIO;
+}
+
+/*
+ * parse entire mds reply
+ */
+static int parse_reply_info(struct ceph_msg *msg,
+			    struct ceph_mds_reply_info_parsed *info,
+			    u64 features)
+{
+	void *p, *end;
+	u32 len;
+	int err;
+
+	info->head = msg->front.iov_base;
+	p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
+	end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
+
+	/* trace */
+	ceph_decode_32_safe(&p, end, len, bad);
+	if (len > 0) {
+		ceph_decode_need(&p, end, len, bad);
+		err = parse_reply_info_trace(&p, p+len, info, features);
+		if (err < 0)
+			goto out_bad;
+	}
+
+	/* extra */
+	ceph_decode_32_safe(&p, end, len, bad);
+	if (len > 0) {
+		ceph_decode_need(&p, end, len, bad);
+		err = parse_reply_info_extra(&p, p+len, info, features);
+		if (err < 0)
+			goto out_bad;
+	}
+
+	/* snap blob */
+	ceph_decode_32_safe(&p, end, len, bad);
+	info->snapblob_len = len;
+	info->snapblob = p;
+	p += len;
+
+	if (p != end)
+		goto bad;
+	return 0;
+
+bad:
+	err = -EIO;
+out_bad:
+	pr_err("mds parse_reply err %d\n", err);
+	return err;
+}
+
+static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
+{
+	if (!info->dir_in)
+		return;
+	free_pages((unsigned long)info->dir_in, get_order(info->dir_buf_size));
+}
+
+
+/*
+ * sessions
+ */
+const char *ceph_session_state_name(int s)
+{
+	switch (s) {
+	case CEPH_MDS_SESSION_NEW: return "new";
+	case CEPH_MDS_SESSION_OPENING: return "opening";
+	case CEPH_MDS_SESSION_OPEN: return "open";
+	case CEPH_MDS_SESSION_HUNG: return "hung";
+	case CEPH_MDS_SESSION_CLOSING: return "closing";
+	case CEPH_MDS_SESSION_RESTARTING: return "restarting";
+	case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
+	default: return "???";
+	}
+}
+
+static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
+{
+	if (atomic_inc_not_zero(&s->s_ref)) {
+		dout("mdsc get_session %p %d -> %d\n", s,
+		     atomic_read(&s->s_ref)-1, atomic_read(&s->s_ref));
+		return s;
+	} else {
+		dout("mdsc get_session %p 0 -- FAIL", s);
+		return NULL;
+	}
+}
+
+void ceph_put_mds_session(struct ceph_mds_session *s)
+{
+	dout("mdsc put_session %p %d -> %d\n", s,
+	     atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1);
+	if (atomic_dec_and_test(&s->s_ref)) {
+		if (s->s_auth.authorizer)
+			ceph_auth_destroy_authorizer(
+				s->s_mdsc->fsc->client->monc.auth,
+				s->s_auth.authorizer);
+		kfree(s);
+	}
+}
+
+/*
+ * called under mdsc->mutex
+ */
+struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
+						   int mds)
+{
+	struct ceph_mds_session *session;
+
+	if (mds >= mdsc->max_sessions || mdsc->sessions[mds] == NULL)
+		return NULL;
+	session = mdsc->sessions[mds];
+	dout("lookup_mds_session %p %d\n", session,
+	     atomic_read(&session->s_ref));
+	get_session(session);
+	return session;
+}
+
+static bool __have_session(struct ceph_mds_client *mdsc, int mds)
+{
+	if (mds >= mdsc->max_sessions)
+		return false;
+	return mdsc->sessions[mds];
+}
+
+static int __verify_registered_session(struct ceph_mds_client *mdsc,
+				       struct ceph_mds_session *s)
+{
+	if (s->s_mds >= mdsc->max_sessions ||
+	    mdsc->sessions[s->s_mds] != s)
+		return -ENOENT;
+	return 0;
+}
+
+/*
+ * create+register a new session for given mds.
+ * called under mdsc->mutex.
+ */
+static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
+						 int mds)
+{
+	struct ceph_mds_session *s;
+
+	if (mds >= mdsc->mdsmap->m_max_mds)
+		return ERR_PTR(-EINVAL);
+
+	s = kzalloc(sizeof(*s), GFP_NOFS);
+	if (!s)
+		return ERR_PTR(-ENOMEM);
+	s->s_mdsc = mdsc;
+	s->s_mds = mds;
+	s->s_state = CEPH_MDS_SESSION_NEW;
+	s->s_ttl = 0;
+	s->s_seq = 0;
+	mutex_init(&s->s_mutex);
+
+	ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);
+
+	spin_lock_init(&s->s_gen_ttl_lock);
+	s->s_cap_gen = 0;
+	s->s_cap_ttl = jiffies - 1;
+
+	spin_lock_init(&s->s_cap_lock);
+	s->s_renew_requested = 0;
+	s->s_renew_seq = 0;
+	INIT_LIST_HEAD(&s->s_caps);
+	s->s_nr_caps = 0;
+	s->s_trim_caps = 0;
+	atomic_set(&s->s_ref, 1);
+	INIT_LIST_HEAD(&s->s_waiting);
+	INIT_LIST_HEAD(&s->s_unsafe);
+	s->s_num_cap_releases = 0;
+	s->s_cap_reconnect = 0;
+	s->s_cap_iterator = NULL;
+	INIT_LIST_HEAD(&s->s_cap_releases);
+	INIT_LIST_HEAD(&s->s_cap_releases_done);
+	INIT_LIST_HEAD(&s->s_cap_flushing);
+	INIT_LIST_HEAD(&s->s_cap_snaps_flushing);
+
+	dout("register_session mds%d\n", mds);
+	if (mds >= mdsc->max_sessions) {
+		int newmax = 1 << get_count_order(mds+1);
+		struct ceph_mds_session **sa;
+
+		dout("register_session realloc to %d\n", newmax);
+		sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
+		if (sa == NULL)
+			goto fail_realloc;
+		if (mdsc->sessions) {
+			memcpy(sa, mdsc->sessions,
+			       mdsc->max_sessions * sizeof(void *));
+			kfree(mdsc->sessions);
+		}
+		mdsc->sessions = sa;
+		mdsc->max_sessions = newmax;
+	}
+	mdsc->sessions[mds] = s;
+	atomic_inc(&mdsc->num_sessions);
+	atomic_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
+
+	ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds,
+		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
+
+	return s;
+
+fail_realloc:
+	kfree(s);
+	return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * called under mdsc->mutex
+ */
+static void __unregister_session(struct ceph_mds_client *mdsc,
+			       struct ceph_mds_session *s)
+{
+	dout("__unregister_session mds%d %p\n", s->s_mds, s);
+	BUG_ON(mdsc->sessions[s->s_mds] != s);
+	mdsc->sessions[s->s_mds] = NULL;
+	ceph_con_close(&s->s_con);
+	ceph_put_mds_session(s);
+	atomic_dec(&mdsc->num_sessions);
+}
+
+/*
+ * drop session refs in request.
+ *
+ * should be last request ref, or hold mdsc->mutex
+ */
+static void put_request_session(struct ceph_mds_request *req)
+{
+	if (req->r_session) {
+		ceph_put_mds_session(req->r_session);
+		req->r_session = NULL;
+	}
+}
+
+void ceph_mdsc_release_request(struct kref *kref)
+{
+	struct ceph_mds_request *req = container_of(kref,
+						    struct ceph_mds_request,
+						    r_kref);
+	destroy_reply_info(&req->r_reply_info);
+	if (req->r_request)
+		ceph_msg_put(req->r_request);
+	if (req->r_reply)
+		ceph_msg_put(req->r_reply);
+	if (req->r_inode) {
+		ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
+		iput(req->r_inode);
+	}
+	if (req->r_locked_dir)
+		ceph_put_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
+	iput(req->r_target_inode);
+	if (req->r_dentry)
+		dput(req->r_dentry);
+	if (req->r_old_dentry)
+		dput(req->r_old_dentry);
+	if (req->r_old_dentry_dir) {
+		/*
+		 * track (and drop pins for) r_old_dentry_dir
+		 * separately, since r_old_dentry's d_parent may have
+		 * changed between the dir mutex being dropped and
+		 * this request being freed.
+		 */
+		ceph_put_cap_refs(ceph_inode(req->r_old_dentry_dir),
+				  CEPH_CAP_PIN);
+		iput(req->r_old_dentry_dir);
+	}
+	kfree(req->r_path1);
+	kfree(req->r_path2);
+	if (req->r_pagelist)
+		ceph_pagelist_release(req->r_pagelist);
+	put_request_session(req);
+	ceph_unreserve_caps(req->r_mdsc, &req->r_caps_reservation);
+	kfree(req);
+}
+
+/*
+ * lookup session, bump ref if found.
+ *
+ * called under mdsc->mutex.
+ */
+static struct ceph_mds_request *__lookup_request(struct ceph_mds_client *mdsc,
+					     u64 tid)
+{
+	struct ceph_mds_request *req;
+	struct rb_node *n = mdsc->request_tree.rb_node;
+
+	while (n) {
+		req = rb_entry(n, struct ceph_mds_request, r_node);
+		if (tid < req->r_tid)
+			n = n->rb_left;
+		else if (tid > req->r_tid)
+			n = n->rb_right;
+		else {
+			ceph_mdsc_get_request(req);
+			return req;
+		}
+	}
+	return NULL;
+}
+
+static void __insert_request(struct ceph_mds_client *mdsc,
+			     struct ceph_mds_request *new)
+{
+	struct rb_node **p = &mdsc->request_tree.rb_node;
+	struct rb_node *parent = NULL;
+	struct ceph_mds_request *req = NULL;
+
+	while (*p) {
+		parent = *p;
+		req = rb_entry(parent, struct ceph_mds_request, r_node);
+		if (new->r_tid < req->r_tid)
+			p = &(*p)->rb_left;
+		else if (new->r_tid > req->r_tid)
+			p = &(*p)->rb_right;
+		else
+			BUG();
+	}
+
+	rb_link_node(&new->r_node, parent, p);
+	rb_insert_color(&new->r_node, &mdsc->request_tree);
+}
+
+/*
+ * Register an in-flight request, and assign a tid.  Link to directory
+ * are modifying (if any).
+ *
+ * Called under mdsc->mutex.
+ */
+static void __register_request(struct ceph_mds_client *mdsc,
+			       struct ceph_mds_request *req,
+			       struct inode *dir)
+{
+	req->r_tid = ++mdsc->last_tid;
+	if (req->r_num_caps)
+		ceph_reserve_caps(mdsc, &req->r_caps_reservation,
+				  req->r_num_caps);
+	dout("__register_request %p tid %lld\n", req, req->r_tid);
+	ceph_mdsc_get_request(req);
+	__insert_request(mdsc, req);
+
+	req->r_uid = current_fsuid();
+	req->r_gid = current_fsgid();
+
+	if (dir) {
+		struct ceph_inode_info *ci = ceph_inode(dir);
+
+		ihold(dir);
+		spin_lock(&ci->i_unsafe_lock);
+		req->r_unsafe_dir = dir;
+		list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
+		spin_unlock(&ci->i_unsafe_lock);
+	}
+}
+
+static void __unregister_request(struct ceph_mds_client *mdsc,
+				 struct ceph_mds_request *req)
+{
+	dout("__unregister_request %p tid %lld\n", req, req->r_tid);
+	rb_erase(&req->r_node, &mdsc->request_tree);
+	RB_CLEAR_NODE(&req->r_node);
+
+	if (req->r_unsafe_dir) {
+		struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
+
+		spin_lock(&ci->i_unsafe_lock);
+		list_del_init(&req->r_unsafe_dir_item);
+		spin_unlock(&ci->i_unsafe_lock);
+
+		iput(req->r_unsafe_dir);
+		req->r_unsafe_dir = NULL;
+	}
+
+	complete_all(&req->r_safe_completion);
+
+	ceph_mdsc_put_request(req);
+}
+
+/*
+ * Choose mds to send request to next.  If there is a hint set in the
+ * request (e.g., due to a prior forward hint from the mds), use that.
+ * Otherwise, consult frag tree and/or caps to identify the
+ * appropriate mds.  If all else fails, choose randomly.
+ *
+ * Called under mdsc->mutex.
+ */
+static struct dentry *get_nonsnap_parent(struct dentry *dentry)
+{
+	/*
+	 * we don't need to worry about protecting the d_parent access
+	 * here because we never renaming inside the snapped namespace
+	 * except to resplice to another snapdir, and either the old or new
+	 * result is a valid result.
+	 */
+	while (!IS_ROOT(dentry) && ceph_snap(d_inode(dentry)) != CEPH_NOSNAP)
+		dentry = dentry->d_parent;
+	return dentry;
+}
+
+static int __choose_mds(struct ceph_mds_client *mdsc,
+			struct ceph_mds_request *req)
+{
+	struct inode *inode;
+	struct ceph_inode_info *ci;
+	struct ceph_cap *cap;
+	int mode = req->r_direct_mode;
+	int mds = -1;
+	u32 hash = req->r_direct_hash;
+	bool is_hash = req->r_direct_is_hash;
+
+	/*
+	 * is there a specific mds we should try?  ignore hint if we have
+	 * no session and the mds is not up (active or recovering).
+	 */
+	if (req->r_resend_mds >= 0 &&
+	    (__have_session(mdsc, req->r_resend_mds) ||
+	     ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
+		dout("choose_mds using resend_mds mds%d\n",
+		     req->r_resend_mds);
+		return req->r_resend_mds;
+	}
+
+	if (mode == USE_RANDOM_MDS)
+		goto random;
+
+	inode = NULL;
+	if (req->r_inode) {
+		inode = req->r_inode;
+	} else if (req->r_dentry) {
+		/* ignore race with rename; old or new d_parent is okay */
+		struct dentry *parent = req->r_dentry->d_parent;
+		struct inode *dir = d_inode(parent);
+
+		if (dir->i_sb != mdsc->fsc->sb) {
+			/* not this fs! */
+			inode = d_inode(req->r_dentry);
+		} else if (ceph_snap(dir) != CEPH_NOSNAP) {
+			/* direct snapped/virtual snapdir requests
+			 * based on parent dir inode */
+			struct dentry *dn = get_nonsnap_parent(parent);
+			inode = d_inode(dn);
+			dout("__choose_mds using nonsnap parent %p\n", inode);
+		} else {
+			/* dentry target */
+			inode = d_inode(req->r_dentry);
+			if (!inode || mode == USE_AUTH_MDS) {
+				/* dir + name */
+				inode = dir;
+				hash = ceph_dentry_hash(dir, req->r_dentry);
+				is_hash = true;
+			}
+		}
+	}
+
+	dout("__choose_mds %p is_hash=%d (%d) mode %d\n", inode, (int)is_hash,
+	     (int)hash, mode);
+	if (!inode)
+		goto random;
+	ci = ceph_inode(inode);
+
+	if (is_hash && S_ISDIR(inode->i_mode)) {
+		struct ceph_inode_frag frag;
+		int found;
+
+		ceph_choose_frag(ci, hash, &frag, &found);
+		if (found) {
+			if (mode == USE_ANY_MDS && frag.ndist > 0) {
+				u8 r;
+
+				/* choose a random replica */
+				get_random_bytes(&r, 1);
+				r %= frag.ndist;
+				mds = frag.dist[r];
+				dout("choose_mds %p %llx.%llx "
+				     "frag %u mds%d (%d/%d)\n",
+				     inode, ceph_vinop(inode),
+				     frag.frag, mds,
+				     (int)r, frag.ndist);
+				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
+				    CEPH_MDS_STATE_ACTIVE)
+					return mds;
+			}
+
+			/* since this file/dir wasn't known to be
+			 * replicated, then we want to look for the
+			 * authoritative mds. */
+			mode = USE_AUTH_MDS;
+			if (frag.mds >= 0) {
+				/* choose auth mds */
+				mds = frag.mds;
+				dout("choose_mds %p %llx.%llx "
+				     "frag %u mds%d (auth)\n",
+				     inode, ceph_vinop(inode), frag.frag, mds);
+				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
+				    CEPH_MDS_STATE_ACTIVE)
+					return mds;
+			}
+		}
+	}
+
+	spin_lock(&ci->i_ceph_lock);
+	cap = NULL;
+	if (mode == USE_AUTH_MDS)
+		cap = ci->i_auth_cap;
+	if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
+		cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
+	if (!cap) {
+		spin_unlock(&ci->i_ceph_lock);
+		goto random;
+	}
+	mds = cap->session->s_mds;
+	dout("choose_mds %p %llx.%llx mds%d (%scap %p)\n",
+	     inode, ceph_vinop(inode), mds,
+	     cap == ci->i_auth_cap ? "auth " : "", cap);
+	spin_unlock(&ci->i_ceph_lock);
+	return mds;
+
+random:
+	mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
+	dout("choose_mds chose random mds%d\n", mds);
+	return mds;
+}
+
+
+/*
+ * session messages
+ */
+static struct ceph_msg *create_session_msg(u32 op, u64 seq)
+{
+	struct ceph_msg *msg;
+	struct ceph_mds_session_head *h;
+
+	msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), GFP_NOFS,
+			   false);
+	if (!msg) {
+		pr_err("create_session_msg ENOMEM creating msg\n");
+		return NULL;
+	}
+	h = msg->front.iov_base;
+	h->op = cpu_to_le32(op);
+	h->seq = cpu_to_le64(seq);
+
+	return msg;
+}
+
+/*
+ * session message, specialization for CEPH_SESSION_REQUEST_OPEN
+ * to include additional client metadata fields.
+ */
+static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u64 seq)
+{
+	struct ceph_msg *msg;
+	struct ceph_mds_session_head *h;
+	int i = -1;
+	int metadata_bytes = 0;
+	int metadata_key_count = 0;
+	struct ceph_options *opt = mdsc->fsc->client->options;
+	void *p;
+
+	const char* metadata[][2] = {
+		{"hostname", utsname()->nodename},
+		{"kernel_version", utsname()->release},
+		{"entity_id", opt->name ? opt->name : ""},
+		{NULL, NULL}
+	};
+
+	/* Calculate serialized length of metadata */
+	metadata_bytes = 4;  /* map length */
+	for (i = 0; metadata[i][0] != NULL; ++i) {
+		metadata_bytes += 8 + strlen(metadata[i][0]) +
+			strlen(metadata[i][1]);
+		metadata_key_count++;
+	}
+
+	/* Allocate the message */
+	msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h) + metadata_bytes,
+			   GFP_NOFS, false);
+	if (!msg) {
+		pr_err("create_session_msg ENOMEM creating msg\n");
+		return NULL;
+	}
+	h = msg->front.iov_base;
+	h->op = cpu_to_le32(CEPH_SESSION_REQUEST_OPEN);
+	h->seq = cpu_to_le64(seq);
+
+	/*
+	 * Serialize client metadata into waiting buffer space, using
+	 * the format that userspace expects for map<string, string>
+	 *
+	 * ClientSession messages with metadata are v2
+	 */
+	msg->hdr.version = cpu_to_le16(2);
+	msg->hdr.compat_version = cpu_to_le16(1);
+
+	/* The write pointer, following the session_head structure */
+	p = msg->front.iov_base + sizeof(*h);
+
+	/* Number of entries in the map */
+	ceph_encode_32(&p, metadata_key_count);
+
+	/* Two length-prefixed strings for each entry in the map */
+	for (i = 0; metadata[i][0] != NULL; ++i) {
+		size_t const key_len = strlen(metadata[i][0]);
+		size_t const val_len = strlen(metadata[i][1]);
+
+		ceph_encode_32(&p, key_len);
+		memcpy(p, metadata[i][0], key_len);
+		p += key_len;
+		ceph_encode_32(&p, val_len);
+		memcpy(p, metadata[i][1], val_len);
+		p += val_len;
+	}
+
+	return msg;
+}
+
+/*
+ * send session open request.
+ *
+ * called under mdsc->mutex
+ */
+static int __open_session(struct ceph_mds_client *mdsc,
+			  struct ceph_mds_session *session)
+{
+	struct ceph_msg *msg;
+	int mstate;
+	int mds = session->s_mds;
+
+	/* wait for mds to go active? */
+	mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
+	dout("open_session to mds%d (%s)\n", mds,
+	     ceph_mds_state_name(mstate));
+	session->s_state = CEPH_MDS_SESSION_OPENING;
+	session->s_renew_requested = jiffies;
+
+	/* send connect message */
+	msg = create_session_open_msg(mdsc, session->s_seq);
+	if (!msg)
+		return -ENOMEM;
+	ceph_con_send(&session->s_con, msg);
+	return 0;
+}
+
+/*
+ * open sessions for any export targets for the given mds
+ *
+ * called under mdsc->mutex
+ */
+static struct ceph_mds_session *
+__open_export_target_session(struct ceph_mds_client *mdsc, int target)
+{
+	struct ceph_mds_session *session;
+
+	session = __ceph_lookup_mds_session(mdsc, target);
+	if (!session) {
+		session = register_session(mdsc, target);
+		if (IS_ERR(session))
+			return session;
+	}
+	if (session->s_state == CEPH_MDS_SESSION_NEW ||
+	    session->s_state == CEPH_MDS_SESSION_CLOSING)
+		__open_session(mdsc, session);
+
+	return session;
+}
+
+struct ceph_mds_session *
+ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target)
+{
+	struct ceph_mds_session *session;
+
+	dout("open_export_target_session to mds%d\n", target);
+
+	mutex_lock(&mdsc->mutex);
+	session = __open_export_target_session(mdsc, target);
+	mutex_unlock(&mdsc->mutex);
+
+	return session;
+}
+
+static void __open_export_target_sessions(struct ceph_mds_client *mdsc,
+					  struct ceph_mds_session *session)
+{
+	struct ceph_mds_info *mi;
+	struct ceph_mds_session *ts;
+	int i, mds = session->s_mds;
+
+	if (mds >= mdsc->mdsmap->m_max_mds)
+		return;
+
+	mi = &mdsc->mdsmap->m_info[mds];
+	dout("open_export_target_sessions for mds%d (%d targets)\n",
+	     session->s_mds, mi->num_export_targets);
+
+	for (i = 0; i < mi->num_export_targets; i++) {
+		ts = __open_export_target_session(mdsc, mi->export_targets[i]);
+		if (!IS_ERR(ts))
+			ceph_put_mds_session(ts);
+	}
+}
+
+void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
+					   struct ceph_mds_session *session)
+{
+	mutex_lock(&mdsc->mutex);
+	__open_export_target_sessions(mdsc, session);
+	mutex_unlock(&mdsc->mutex);
+}
+
+/*
+ * session caps
+ */
+
+/*
+ * Free preallocated cap messages assigned to this session
+ */
+static void cleanup_cap_releases(struct ceph_mds_session *session)
+{
+	struct ceph_msg *msg;
+
+	spin_lock(&session->s_cap_lock);
+	while (!list_empty(&session->s_cap_releases)) {
+		msg = list_first_entry(&session->s_cap_releases,
+				       struct ceph_msg, list_head);
+		list_del_init(&msg->list_head);
+		ceph_msg_put(msg);
+	}
+	while (!list_empty(&session->s_cap_releases_done)) {
+		msg = list_first_entry(&session->s_cap_releases_done,
+				       struct ceph_msg, list_head);
+		list_del_init(&msg->list_head);
+		ceph_msg_put(msg);
+	}
+	spin_unlock(&session->s_cap_lock);
+}
+
+static void cleanup_session_requests(struct ceph_mds_client *mdsc,
+				     struct ceph_mds_session *session)
+{
+	struct ceph_mds_request *req;
+	struct rb_node *p;
+
+	dout("cleanup_session_requests mds%d\n", session->s_mds);
+	mutex_lock(&mdsc->mutex);
+	while (!list_empty(&session->s_unsafe)) {
+		req = list_first_entry(&session->s_unsafe,
+				       struct ceph_mds_request, r_unsafe_item);
+		list_del_init(&req->r_unsafe_item);
+		pr_info(" dropping unsafe request %llu\n", req->r_tid);
+		__unregister_request(mdsc, req);
+	}
+	/* zero r_attempts, so kick_requests() will re-send requests */
+	p = rb_first(&mdsc->request_tree);
+	while (p) {
+		req = rb_entry(p, struct ceph_mds_request, r_node);
+		p = rb_next(p);
+		if (req->r_session &&
+		    req->r_session->s_mds == session->s_mds)
+			req->r_attempts = 0;
+	}
+	mutex_unlock(&mdsc->mutex);
+}
+
+/*
+ * Helper to safely iterate over all caps associated with a session, with
+ * special care taken to handle a racing __ceph_remove_cap().
+ *
+ * Caller must hold session s_mutex.
+ */
+static int iterate_session_caps(struct ceph_mds_session *session,
+				 int (*cb)(struct inode *, struct ceph_cap *,
+					    void *), void *arg)
+{
+	struct list_head *p;
+	struct ceph_cap *cap;
+	struct inode *inode, *last_inode = NULL;
+	struct ceph_cap *old_cap = NULL;
+	int ret;
+
+	dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
+	spin_lock(&session->s_cap_lock);
+	p = session->s_caps.next;
+	while (p != &session->s_caps) {
+		cap = list_entry(p, struct ceph_cap, session_caps);
+		inode = igrab(&cap->ci->vfs_inode);
+		if (!inode) {
+			p = p->next;
+			continue;
+		}
+		session->s_cap_iterator = cap;
+		spin_unlock(&session->s_cap_lock);
+
+		if (last_inode) {
+			iput(last_inode);
+			last_inode = NULL;
+		}
+		if (old_cap) {
+			ceph_put_cap(session->s_mdsc, old_cap);
+			old_cap = NULL;
+		}
+
+		ret = cb(inode, cap, arg);
+		last_inode = inode;
+
+		spin_lock(&session->s_cap_lock);
+		p = p->next;
+		if (cap->ci == NULL) {
+			dout("iterate_session_caps  finishing cap %p removal\n",
+			     cap);
+			BUG_ON(cap->session != session);
+			list_del_init(&cap->session_caps);
+			session->s_nr_caps--;
+			cap->session = NULL;
+			old_cap = cap;  /* put_cap it w/o locks held */
+		}
+		if (ret < 0)
+			goto out;
+	}
+	ret = 0;
+out:
+	session->s_cap_iterator = NULL;
+	spin_unlock(&session->s_cap_lock);
+
+	iput(last_inode);
+	if (old_cap)
+		ceph_put_cap(session->s_mdsc, old_cap);
+
+	return ret;
+}
+
+static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
+				  void *arg)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int drop = 0;
+
+	dout("removing cap %p, ci is %p, inode is %p\n",
+	     cap, ci, &ci->vfs_inode);
+	spin_lock(&ci->i_ceph_lock);
+	__ceph_remove_cap(cap, false);
+	if (!ci->i_auth_cap) {
+		struct ceph_mds_client *mdsc =
+			ceph_sb_to_client(inode->i_sb)->mdsc;
+
+		spin_lock(&mdsc->cap_dirty_lock);
+		if (!list_empty(&ci->i_dirty_item)) {
+			pr_info(" dropping dirty %s state for %p %lld\n",
+				ceph_cap_string(ci->i_dirty_caps),
+				inode, ceph_ino(inode));
+			ci->i_dirty_caps = 0;
+			list_del_init(&ci->i_dirty_item);
+			drop = 1;
+		}
+		if (!list_empty(&ci->i_flushing_item)) {
+			pr_info(" dropping dirty+flushing %s state for %p %lld\n",
+				ceph_cap_string(ci->i_flushing_caps),
+				inode, ceph_ino(inode));
+			ci->i_flushing_caps = 0;
+			list_del_init(&ci->i_flushing_item);
+			mdsc->num_cap_flushing--;
+			drop = 1;
+		}
+		spin_unlock(&mdsc->cap_dirty_lock);
+	}
+	spin_unlock(&ci->i_ceph_lock);
+	while (drop--)
+		iput(inode);
+	return 0;
+}
+
+/*
+ * caller must hold session s_mutex
+ */
+static void remove_session_caps(struct ceph_mds_session *session)
+{
+	dout("remove_session_caps on %p\n", session);
+	iterate_session_caps(session, remove_session_caps_cb, NULL);
+
+	spin_lock(&session->s_cap_lock);
+	if (session->s_nr_caps > 0) {
+		struct super_block *sb = session->s_mdsc->fsc->sb;
+		struct inode *inode;
+		struct ceph_cap *cap, *prev = NULL;
+		struct ceph_vino vino;
+		/*
+		 * iterate_session_caps() skips inodes that are being
+		 * deleted, we need to wait until deletions are complete.
+		 * __wait_on_freeing_inode() is designed for the job,
+		 * but it is not exported, so use lookup inode function
+		 * to access it.
+		 */
+		while (!list_empty(&session->s_caps)) {
+			cap = list_entry(session->s_caps.next,
+					 struct ceph_cap, session_caps);
+			if (cap == prev)
+				break;
+			prev = cap;
+			vino = cap->ci->i_vino;
+			spin_unlock(&session->s_cap_lock);
+
+			inode = ceph_find_inode(sb, vino);
+			iput(inode);
+
+			spin_lock(&session->s_cap_lock);
+		}
+	}
+	spin_unlock(&session->s_cap_lock);
+
+	BUG_ON(session->s_nr_caps > 0);
+	BUG_ON(!list_empty(&session->s_cap_flushing));
+	cleanup_cap_releases(session);
+}
+
+/*
+ * wake up any threads waiting on this session's caps.  if the cap is
+ * old (didn't get renewed on the client reconnect), remove it now.
+ *
+ * caller must hold s_mutex.
+ */
+static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
+			      void *arg)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	wake_up_all(&ci->i_cap_wq);
+	if (arg) {
+		spin_lock(&ci->i_ceph_lock);
+		ci->i_wanted_max_size = 0;
+		ci->i_requested_max_size = 0;
+		spin_unlock(&ci->i_ceph_lock);
+	}
+	return 0;
+}
+
+static void wake_up_session_caps(struct ceph_mds_session *session,
+				 int reconnect)
+{
+	dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
+	iterate_session_caps(session, wake_up_session_cb,
+			     (void *)(unsigned long)reconnect);
+}
+
+/*
+ * Send periodic message to MDS renewing all currently held caps.  The
+ * ack will reset the expiration for all caps from this session.
+ *
+ * caller holds s_mutex
+ */
+static int send_renew_caps(struct ceph_mds_client *mdsc,
+			   struct ceph_mds_session *session)
+{
+	struct ceph_msg *msg;
+	int state;
+
+	if (time_after_eq(jiffies, session->s_cap_ttl) &&
+	    time_after_eq(session->s_cap_ttl, session->s_renew_requested))
+		pr_info("mds%d caps stale\n", session->s_mds);
+	session->s_renew_requested = jiffies;
+
+	/* do not try to renew caps until a recovering mds has reconnected
+	 * with its clients. */
+	state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
+	if (state < CEPH_MDS_STATE_RECONNECT) {
+		dout("send_renew_caps ignoring mds%d (%s)\n",
+		     session->s_mds, ceph_mds_state_name(state));
+		return 0;
+	}
+
+	dout("send_renew_caps to mds%d (%s)\n", session->s_mds,
+		ceph_mds_state_name(state));
+	msg = create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
+				 ++session->s_renew_seq);
+	if (!msg)
+		return -ENOMEM;
+	ceph_con_send(&session->s_con, msg);
+	return 0;
+}
+
+static int send_flushmsg_ack(struct ceph_mds_client *mdsc,
+			     struct ceph_mds_session *session, u64 seq)
+{
+	struct ceph_msg *msg;
+
+	dout("send_flushmsg_ack to mds%d (%s)s seq %lld\n",
+	     session->s_mds, ceph_session_state_name(session->s_state), seq);
+	msg = create_session_msg(CEPH_SESSION_FLUSHMSG_ACK, seq);
+	if (!msg)
+		return -ENOMEM;
+	ceph_con_send(&session->s_con, msg);
+	return 0;
+}
+
+
+/*
+ * Note new cap ttl, and any transition from stale -> not stale (fresh?).
+ *
+ * Called under session->s_mutex
+ */
+static void renewed_caps(struct ceph_mds_client *mdsc,
+			 struct ceph_mds_session *session, int is_renew)
+{
+	int was_stale;
+	int wake = 0;
+
+	spin_lock(&session->s_cap_lock);
+	was_stale = is_renew && time_after_eq(jiffies, session->s_cap_ttl);
+
+	session->s_cap_ttl = session->s_renew_requested +
+		mdsc->mdsmap->m_session_timeout*HZ;
+
+	if (was_stale) {
+		if (time_before(jiffies, session->s_cap_ttl)) {
+			pr_info("mds%d caps renewed\n", session->s_mds);
+			wake = 1;
+		} else {
+			pr_info("mds%d caps still stale\n", session->s_mds);
+		}
+	}
+	dout("renewed_caps mds%d ttl now %lu, was %s, now %s\n",
+	     session->s_mds, session->s_cap_ttl, was_stale ? "stale" : "fresh",
+	     time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
+	spin_unlock(&session->s_cap_lock);
+
+	if (wake)
+		wake_up_session_caps(session, 0);
+}
+
+/*
+ * send a session close request
+ */
+static int request_close_session(struct ceph_mds_client *mdsc,
+				 struct ceph_mds_session *session)
+{
+	struct ceph_msg *msg;
+
+	dout("request_close_session mds%d state %s seq %lld\n",
+	     session->s_mds, ceph_session_state_name(session->s_state),
+	     session->s_seq);
+	msg = create_session_msg(CEPH_SESSION_REQUEST_CLOSE, session->s_seq);
+	if (!msg)
+		return -ENOMEM;
+	ceph_con_send(&session->s_con, msg);
+	return 0;
+}
+
+/*
+ * Called with s_mutex held.
+ */
+static int __close_session(struct ceph_mds_client *mdsc,
+			 struct ceph_mds_session *session)
+{
+	if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
+		return 0;
+	session->s_state = CEPH_MDS_SESSION_CLOSING;
+	return request_close_session(mdsc, session);
+}
+
+/*
+ * Trim old(er) caps.
+ *
+ * Because we can't cache an inode without one or more caps, we do
+ * this indirectly: if a cap is unused, we prune its aliases, at which
+ * point the inode will hopefully get dropped to.
+ *
+ * Yes, this is a bit sloppy.  Our only real goal here is to respond to
+ * memory pressure from the MDS, though, so it needn't be perfect.
+ */
+static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
+{
+	struct ceph_mds_session *session = arg;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int used, wanted, oissued, mine;
+
+	if (session->s_trim_caps <= 0)
+		return -1;
+
+	spin_lock(&ci->i_ceph_lock);
+	mine = cap->issued | cap->implemented;
+	used = __ceph_caps_used(ci);
+	wanted = __ceph_caps_file_wanted(ci);
+	oissued = __ceph_caps_issued_other(ci, cap);
+
+	dout("trim_caps_cb %p cap %p mine %s oissued %s used %s wanted %s\n",
+	     inode, cap, ceph_cap_string(mine), ceph_cap_string(oissued),
+	     ceph_cap_string(used), ceph_cap_string(wanted));
+	if (cap == ci->i_auth_cap) {
+		if (ci->i_dirty_caps | ci->i_flushing_caps)
+			goto out;
+		if ((used | wanted) & CEPH_CAP_ANY_WR)
+			goto out;
+	}
+	if ((used | wanted) & ~oissued & mine)
+		goto out;   /* we need these caps */
+
+	session->s_trim_caps--;
+	if (oissued) {
+		/* we aren't the only cap.. just remove us */
+		__ceph_remove_cap(cap, true);
+	} else {
+		/* try to drop referring dentries */
+		spin_unlock(&ci->i_ceph_lock);
+		d_prune_aliases(inode);
+		dout("trim_caps_cb %p cap %p  pruned, count now %d\n",
+		     inode, cap, atomic_read(&inode->i_count));
+		return 0;
+	}
+
+out:
+	spin_unlock(&ci->i_ceph_lock);
+	return 0;
+}
+
+/*
+ * Trim session cap count down to some max number.
+ */
+static int trim_caps(struct ceph_mds_client *mdsc,
+		     struct ceph_mds_session *session,
+		     int max_caps)
+{
+	int trim_caps = session->s_nr_caps - max_caps;
+
+	dout("trim_caps mds%d start: %d / %d, trim %d\n",
+	     session->s_mds, session->s_nr_caps, max_caps, trim_caps);
+	if (trim_caps > 0) {
+		session->s_trim_caps = trim_caps;
+		iterate_session_caps(session, trim_caps_cb, session);
+		dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
+		     session->s_mds, session->s_nr_caps, max_caps,
+			trim_caps - session->s_trim_caps);
+		session->s_trim_caps = 0;
+	}
+
+	ceph_add_cap_releases(mdsc, session);
+	ceph_send_cap_releases(mdsc, session);
+	return 0;
+}
+
+/*
+ * Allocate cap_release messages.  If there is a partially full message
+ * in the queue, try to allocate enough to cover it's remainder, so that
+ * we can send it immediately.
+ *
+ * Called under s_mutex.
+ */
+int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
+			  struct ceph_mds_session *session)
+{
+	struct ceph_msg *msg, *partial = NULL;
+	struct ceph_mds_cap_release *head;
+	int err = -ENOMEM;
+	int extra = mdsc->fsc->mount_options->cap_release_safety;
+	int num;
+
+	dout("add_cap_releases %p mds%d extra %d\n", session, session->s_mds,
+	     extra);
+
+	spin_lock(&session->s_cap_lock);
+
+	if (!list_empty(&session->s_cap_releases)) {
+		msg = list_first_entry(&session->s_cap_releases,
+				       struct ceph_msg,
+				 list_head);
+		head = msg->front.iov_base;
+		num = le32_to_cpu(head->num);
+		if (num) {
+			dout(" partial %p with (%d/%d)\n", msg, num,
+			     (int)CEPH_CAPS_PER_RELEASE);
+			extra += CEPH_CAPS_PER_RELEASE - num;
+			partial = msg;
+		}
+	}
+	while (session->s_num_cap_releases < session->s_nr_caps + extra) {
+		spin_unlock(&session->s_cap_lock);
+		msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE, PAGE_CACHE_SIZE,
+				   GFP_NOFS, false);
+		if (!msg)
+			goto out_unlocked;
+		dout("add_cap_releases %p msg %p now %d\n", session, msg,
+		     (int)msg->front.iov_len);
+		head = msg->front.iov_base;
+		head->num = cpu_to_le32(0);
+		msg->front.iov_len = sizeof(*head);
+		spin_lock(&session->s_cap_lock);
+		list_add(&msg->list_head, &session->s_cap_releases);
+		session->s_num_cap_releases += CEPH_CAPS_PER_RELEASE;
+	}
+
+	if (partial) {
+		head = partial->front.iov_base;
+		num = le32_to_cpu(head->num);
+		dout(" queueing partial %p with %d/%d\n", partial, num,
+		     (int)CEPH_CAPS_PER_RELEASE);
+		list_move_tail(&partial->list_head,
+			       &session->s_cap_releases_done);
+		session->s_num_cap_releases -= CEPH_CAPS_PER_RELEASE - num;
+	}
+	err = 0;
+	spin_unlock(&session->s_cap_lock);
+out_unlocked:
+	return err;
+}
+
+static int check_cap_flush(struct inode *inode, u64 want_flush_seq)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int ret;
+	spin_lock(&ci->i_ceph_lock);
+	if (ci->i_flushing_caps)
+		ret = ci->i_cap_flush_seq >= want_flush_seq;
+	else
+		ret = 1;
+	spin_unlock(&ci->i_ceph_lock);
+	return ret;
+}
+
+/*
+ * flush all dirty inode data to disk.
+ *
+ * returns true if we've flushed through want_flush_seq
+ */
+static void wait_caps_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
+{
+	int mds;
+
+	dout("check_cap_flush want %lld\n", want_flush_seq);
+	mutex_lock(&mdsc->mutex);
+	for (mds = 0; mds < mdsc->max_sessions; mds++) {
+		struct ceph_mds_session *session = mdsc->sessions[mds];
+		struct inode *inode = NULL;
+
+		if (!session)
+			continue;
+		get_session(session);
+		mutex_unlock(&mdsc->mutex);
+
+		mutex_lock(&session->s_mutex);
+		if (!list_empty(&session->s_cap_flushing)) {
+			struct ceph_inode_info *ci =
+				list_entry(session->s_cap_flushing.next,
+					   struct ceph_inode_info,
+					   i_flushing_item);
+
+			if (!check_cap_flush(&ci->vfs_inode, want_flush_seq)) {
+				dout("check_cap_flush still flushing %p "
+				     "seq %lld <= %lld to mds%d\n",
+				     &ci->vfs_inode, ci->i_cap_flush_seq,
+				     want_flush_seq, session->s_mds);
+				inode = igrab(&ci->vfs_inode);
+			}
+		}
+		mutex_unlock(&session->s_mutex);
+		ceph_put_mds_session(session);
+
+		if (inode) {
+			wait_event(mdsc->cap_flushing_wq,
+				   check_cap_flush(inode, want_flush_seq));
+			iput(inode);
+		}
+
+		mutex_lock(&mdsc->mutex);
+	}
+
+	mutex_unlock(&mdsc->mutex);
+	dout("check_cap_flush ok, flushed thru %lld\n", want_flush_seq);
+}
+
+/*
+ * called under s_mutex
+ */
+void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
+			    struct ceph_mds_session *session)
+{
+	struct ceph_msg *msg;
+
+	dout("send_cap_releases mds%d\n", session->s_mds);
+	spin_lock(&session->s_cap_lock);
+	while (!list_empty(&session->s_cap_releases_done)) {
+		msg = list_first_entry(&session->s_cap_releases_done,
+				 struct ceph_msg, list_head);
+		list_del_init(&msg->list_head);
+		spin_unlock(&session->s_cap_lock);
+		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
+		dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
+		ceph_con_send(&session->s_con, msg);
+		spin_lock(&session->s_cap_lock);
+	}
+	spin_unlock(&session->s_cap_lock);
+}
+
+static void discard_cap_releases(struct ceph_mds_client *mdsc,
+				 struct ceph_mds_session *session)
+{
+	struct ceph_msg *msg;
+	struct ceph_mds_cap_release *head;
+	unsigned num;
+
+	dout("discard_cap_releases mds%d\n", session->s_mds);
+
+	if (!list_empty(&session->s_cap_releases)) {
+		/* zero out the in-progress message */
+		msg = list_first_entry(&session->s_cap_releases,
+					struct ceph_msg, list_head);
+		head = msg->front.iov_base;
+		num = le32_to_cpu(head->num);
+		dout("discard_cap_releases mds%d %p %u\n",
+		     session->s_mds, msg, num);
+		head->num = cpu_to_le32(0);
+		msg->front.iov_len = sizeof(*head);
+		session->s_num_cap_releases += num;
+	}
+
+	/* requeue completed messages */
+	while (!list_empty(&session->s_cap_releases_done)) {
+		msg = list_first_entry(&session->s_cap_releases_done,
+				 struct ceph_msg, list_head);
+		list_del_init(&msg->list_head);
+
+		head = msg->front.iov_base;
+		num = le32_to_cpu(head->num);
+		dout("discard_cap_releases mds%d %p %u\n", session->s_mds, msg,
+		     num);
+		session->s_num_cap_releases += num;
+		head->num = cpu_to_le32(0);
+		msg->front.iov_len = sizeof(*head);
+		list_add(&msg->list_head, &session->s_cap_releases);
+	}
+}
+
+/*
+ * requests
+ */
+
+int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
+				    struct inode *dir)
+{
+	struct ceph_inode_info *ci = ceph_inode(dir);
+	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
+	struct ceph_mount_options *opt = req->r_mdsc->fsc->mount_options;
+	size_t size = sizeof(*rinfo->dir_in) + sizeof(*rinfo->dir_dname_len) +
+		      sizeof(*rinfo->dir_dname) + sizeof(*rinfo->dir_dlease);
+	int order, num_entries;
+
+	spin_lock(&ci->i_ceph_lock);
+	num_entries = ci->i_files + ci->i_subdirs;
+	spin_unlock(&ci->i_ceph_lock);
+	num_entries = max(num_entries, 1);
+	num_entries = min(num_entries, opt->max_readdir);
+
+	order = get_order(size * num_entries);
+	while (order >= 0) {
+		rinfo->dir_in = (void*)__get_free_pages(GFP_NOFS | __GFP_NOWARN,
+							order);
+		if (rinfo->dir_in)
+			break;
+		order--;
+	}
+	if (!rinfo->dir_in)
+		return -ENOMEM;
+
+	num_entries = (PAGE_SIZE << order) / size;
+	num_entries = min(num_entries, opt->max_readdir);
+
+	rinfo->dir_buf_size = PAGE_SIZE << order;
+	req->r_num_caps = num_entries + 1;
+	req->r_args.readdir.max_entries = cpu_to_le32(num_entries);
+	req->r_args.readdir.max_bytes = cpu_to_le32(opt->max_readdir_bytes);
+	return 0;
+}
+
+/*
+ * Create an mds request.
+ */
+struct ceph_mds_request *
+ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
+{
+	struct ceph_mds_request *req = kzalloc(sizeof(*req), GFP_NOFS);
+
+	if (!req)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&req->r_fill_mutex);
+	req->r_mdsc = mdsc;
+	req->r_started = jiffies;
+	req->r_resend_mds = -1;
+	INIT_LIST_HEAD(&req->r_unsafe_dir_item);
+	req->r_fmode = -1;
+	kref_init(&req->r_kref);
+	INIT_LIST_HEAD(&req->r_wait);
+	init_completion(&req->r_completion);
+	init_completion(&req->r_safe_completion);
+	INIT_LIST_HEAD(&req->r_unsafe_item);
+
+	req->r_stamp = CURRENT_TIME;
+
+	req->r_op = op;
+	req->r_direct_mode = mode;
+	return req;
+}
+
+/*
+ * return oldest (lowest) request, tid in request tree, 0 if none.
+ *
+ * called under mdsc->mutex.
+ */
+static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
+{
+	if (RB_EMPTY_ROOT(&mdsc->request_tree))
+		return NULL;
+	return rb_entry(rb_first(&mdsc->request_tree),
+			struct ceph_mds_request, r_node);
+}
+
+static u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
+{
+	struct ceph_mds_request *req = __get_oldest_req(mdsc);
+
+	if (req)
+		return req->r_tid;
+	return 0;
+}
+
+/*
+ * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
+ * on build_path_from_dentry in fs/cifs/dir.c.
+ *
+ * If @stop_on_nosnap, generate path relative to the first non-snapped
+ * inode.
+ *
+ * Encode hidden .snap dirs as a double /, i.e.
+ *   foo/.snap/bar -> foo//bar
+ */
+char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
+			   int stop_on_nosnap)
+{
+	struct dentry *temp;
+	char *path;
+	int len, pos;
+	unsigned seq;
+
+	if (dentry == NULL)
+		return ERR_PTR(-EINVAL);
+
+retry:
+	len = 0;
+	seq = read_seqbegin(&rename_lock);
+	rcu_read_lock();
+	for (temp = dentry; !IS_ROOT(temp);) {
+		struct inode *inode = d_inode(temp);
+		if (inode && ceph_snap(inode) == CEPH_SNAPDIR)
+			len++;  /* slash only */
+		else if (stop_on_nosnap && inode &&
+			 ceph_snap(inode) == CEPH_NOSNAP)
+			break;
+		else
+			len += 1 + temp->d_name.len;
+		temp = temp->d_parent;
+	}
+	rcu_read_unlock();
+	if (len)
+		len--;  /* no leading '/' */
+
+	path = kmalloc(len+1, GFP_NOFS);
+	if (path == NULL)
+		return ERR_PTR(-ENOMEM);
+	pos = len;
+	path[pos] = 0;	/* trailing null */
+	rcu_read_lock();
+	for (temp = dentry; !IS_ROOT(temp) && pos != 0; ) {
+		struct inode *inode;
+
+		spin_lock(&temp->d_lock);
+		inode = d_inode(temp);
+		if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
+			dout("build_path path+%d: %p SNAPDIR\n",
+			     pos, temp);
+		} else if (stop_on_nosnap && inode &&
+			   ceph_snap(inode) == CEPH_NOSNAP) {
+			spin_unlock(&temp->d_lock);
+			break;
+		} else {
+			pos -= temp->d_name.len;
+			if (pos < 0) {
+				spin_unlock(&temp->d_lock);
+				break;
+			}
+			strncpy(path + pos, temp->d_name.name,
+				temp->d_name.len);
+		}
+		spin_unlock(&temp->d_lock);
+		if (pos)
+			path[--pos] = '/';
+		temp = temp->d_parent;
+	}
+	rcu_read_unlock();
+	if (pos != 0 || read_seqretry(&rename_lock, seq)) {
+		pr_err("build_path did not end path lookup where "
+		       "expected, namelen is %d, pos is %d\n", len, pos);
+		/* presumably this is only possible if racing with a
+		   rename of one of the parent directories (we can not
+		   lock the dentries above us to prevent this, but
+		   retrying should be harmless) */
+		kfree(path);
+		goto retry;
+	}
+
+	*base = ceph_ino(d_inode(temp));
+	*plen = len;
+	dout("build_path on %p %d built %llx '%.*s'\n",
+	     dentry, d_count(dentry), *base, len, path);
+	return path;
+}
+
+static int build_dentry_path(struct dentry *dentry,
+			     const char **ppath, int *ppathlen, u64 *pino,
+			     int *pfreepath)
+{
+	char *path;
+
+	if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_NOSNAP) {
+		*pino = ceph_ino(d_inode(dentry->d_parent));
+		*ppath = dentry->d_name.name;
+		*ppathlen = dentry->d_name.len;
+		return 0;
+	}
+	path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	*ppath = path;
+	*pfreepath = 1;
+	return 0;
+}
+
+static int build_inode_path(struct inode *inode,
+			    const char **ppath, int *ppathlen, u64 *pino,
+			    int *pfreepath)
+{
+	struct dentry *dentry;
+	char *path;
+
+	if (ceph_snap(inode) == CEPH_NOSNAP) {
+		*pino = ceph_ino(inode);
+		*ppathlen = 0;
+		return 0;
+	}
+	dentry = d_find_alias(inode);
+	path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
+	dput(dentry);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	*ppath = path;
+	*pfreepath = 1;
+	return 0;
+}
+
+/*
+ * request arguments may be specified via an inode *, a dentry *, or
+ * an explicit ino+path.
+ */
+static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
+				  const char *rpath, u64 rino,
+				  const char **ppath, int *pathlen,
+				  u64 *ino, int *freepath)
+{
+	int r = 0;
+
+	if (rinode) {
+		r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
+		dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
+		     ceph_snap(rinode));
+	} else if (rdentry) {
+		r = build_dentry_path(rdentry, ppath, pathlen, ino, freepath);
+		dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
+		     *ppath);
+	} else if (rpath || rino) {
+		*ino = rino;
+		*ppath = rpath;
+		*pathlen = rpath ? strlen(rpath) : 0;
+		dout(" path %.*s\n", *pathlen, rpath);
+	}
+
+	return r;
+}
+
+/*
+ * called under mdsc->mutex
+ */
+static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
+					       struct ceph_mds_request *req,
+					       int mds, bool drop_cap_releases)
+{
+	struct ceph_msg *msg;
+	struct ceph_mds_request_head *head;
+	const char *path1 = NULL;
+	const char *path2 = NULL;
+	u64 ino1 = 0, ino2 = 0;
+	int pathlen1 = 0, pathlen2 = 0;
+	int freepath1 = 0, freepath2 = 0;
+	int len;
+	u16 releases;
+	void *p, *end;
+	int ret;
+
+	ret = set_request_path_attr(req->r_inode, req->r_dentry,
+			      req->r_path1, req->r_ino1.ino,
+			      &path1, &pathlen1, &ino1, &freepath1);
+	if (ret < 0) {
+		msg = ERR_PTR(ret);
+		goto out;
+	}
+
+	ret = set_request_path_attr(NULL, req->r_old_dentry,
+			      req->r_path2, req->r_ino2.ino,
+			      &path2, &pathlen2, &ino2, &freepath2);
+	if (ret < 0) {
+		msg = ERR_PTR(ret);
+		goto out_free1;
+	}
+
+	len = sizeof(*head) +
+		pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64)) +
+		sizeof(struct timespec);
+
+	/* calculate (max) length for cap releases */
+	len += sizeof(struct ceph_mds_request_release) *
+		(!!req->r_inode_drop + !!req->r_dentry_drop +
+		 !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
+	if (req->r_dentry_drop)
+		len += req->r_dentry->d_name.len;
+	if (req->r_old_dentry_drop)
+		len += req->r_old_dentry->d_name.len;
+
+	msg = ceph_msg_new(CEPH_MSG_CLIENT_REQUEST, len, GFP_NOFS, false);
+	if (!msg) {
+		msg = ERR_PTR(-ENOMEM);
+		goto out_free2;
+	}
+
+	msg->hdr.version = cpu_to_le16(2);
+	msg->hdr.tid = cpu_to_le64(req->r_tid);
+
+	head = msg->front.iov_base;
+	p = msg->front.iov_base + sizeof(*head);
+	end = msg->front.iov_base + msg->front.iov_len;
+
+	head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
+	head->op = cpu_to_le32(req->r_op);
+	head->caller_uid = cpu_to_le32(from_kuid(&init_user_ns, req->r_uid));
+	head->caller_gid = cpu_to_le32(from_kgid(&init_user_ns, req->r_gid));
+	head->args = req->r_args;
+
+	ceph_encode_filepath(&p, end, ino1, path1);
+	ceph_encode_filepath(&p, end, ino2, path2);
+
+	/* make note of release offset, in case we need to replay */
+	req->r_request_release_offset = p - msg->front.iov_base;
+
+	/* cap releases */
+	releases = 0;
+	if (req->r_inode_drop)
+		releases += ceph_encode_inode_release(&p,
+		      req->r_inode ? req->r_inode : d_inode(req->r_dentry),
+		      mds, req->r_inode_drop, req->r_inode_unless, 0);
+	if (req->r_dentry_drop)
+		releases += ceph_encode_dentry_release(&p, req->r_dentry,
+		       mds, req->r_dentry_drop, req->r_dentry_unless);
+	if (req->r_old_dentry_drop)
+		releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
+		       mds, req->r_old_dentry_drop, req->r_old_dentry_unless);
+	if (req->r_old_inode_drop)
+		releases += ceph_encode_inode_release(&p,
+		      d_inode(req->r_old_dentry),
+		      mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
+
+	if (drop_cap_releases) {
+		releases = 0;
+		p = msg->front.iov_base + req->r_request_release_offset;
+	}
+
+	head->num_releases = cpu_to_le16(releases);
+
+	/* time stamp */
+	{
+		struct ceph_timespec ts;
+		ceph_encode_timespec(&ts, &req->r_stamp);
+		ceph_encode_copy(&p, &ts, sizeof(ts));
+	}
+
+	BUG_ON(p > end);
+	msg->front.iov_len = p - msg->front.iov_base;
+	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
+
+	if (req->r_pagelist) {
+		struct ceph_pagelist *pagelist = req->r_pagelist;
+		atomic_inc(&pagelist->refcnt);
+		ceph_msg_data_add_pagelist(msg, pagelist);
+		msg->hdr.data_len = cpu_to_le32(pagelist->length);
+	} else {
+		msg->hdr.data_len = 0;
+	}
+
+	msg->hdr.data_off = cpu_to_le16(0);
+
+out_free2:
+	if (freepath2)
+		kfree((char *)path2);
+out_free1:
+	if (freepath1)
+		kfree((char *)path1);
+out:
+	return msg;
+}
+
+/*
+ * called under mdsc->mutex if error, under no mutex if
+ * success.
+ */
+static void complete_request(struct ceph_mds_client *mdsc,
+			     struct ceph_mds_request *req)
+{
+	if (req->r_callback)
+		req->r_callback(mdsc, req);
+	else
+		complete_all(&req->r_completion);
+}
+
+/*
+ * called under mdsc->mutex
+ */
+static int __prepare_send_request(struct ceph_mds_client *mdsc,
+				  struct ceph_mds_request *req,
+				  int mds, bool drop_cap_releases)
+{
+	struct ceph_mds_request_head *rhead;
+	struct ceph_msg *msg;
+	int flags = 0;
+
+	req->r_attempts++;
+	if (req->r_inode) {
+		struct ceph_cap *cap =
+			ceph_get_cap_for_mds(ceph_inode(req->r_inode), mds);
+
+		if (cap)
+			req->r_sent_on_mseq = cap->mseq;
+		else
+			req->r_sent_on_mseq = -1;
+	}
+	dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
+	     req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
+
+	if (req->r_got_unsafe) {
+		void *p;
+		/*
+		 * Replay.  Do not regenerate message (and rebuild
+		 * paths, etc.); just use the original message.
+		 * Rebuilding paths will break for renames because
+		 * d_move mangles the src name.
+		 */
+		msg = req->r_request;
+		rhead = msg->front.iov_base;
+
+		flags = le32_to_cpu(rhead->flags);
+		flags |= CEPH_MDS_FLAG_REPLAY;
+		rhead->flags = cpu_to_le32(flags);
+
+		if (req->r_target_inode)
+			rhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
+
+		rhead->num_retry = req->r_attempts - 1;
+
+		/* remove cap/dentry releases from message */
+		rhead->num_releases = 0;
+
+		/* time stamp */
+		p = msg->front.iov_base + req->r_request_release_offset;
+		{
+			struct ceph_timespec ts;
+			ceph_encode_timespec(&ts, &req->r_stamp);
+			ceph_encode_copy(&p, &ts, sizeof(ts));
+		}
+
+		msg->front.iov_len = p - msg->front.iov_base;
+		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
+		return 0;
+	}
+
+	if (req->r_request) {
+		ceph_msg_put(req->r_request);
+		req->r_request = NULL;
+	}
+	msg = create_request_message(mdsc, req, mds, drop_cap_releases);
+	if (IS_ERR(msg)) {
+		req->r_err = PTR_ERR(msg);
+		complete_request(mdsc, req);
+		return PTR_ERR(msg);
+	}
+	req->r_request = msg;
+
+	rhead = msg->front.iov_base;
+	rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
+	if (req->r_got_unsafe)
+		flags |= CEPH_MDS_FLAG_REPLAY;
+	if (req->r_locked_dir)
+		flags |= CEPH_MDS_FLAG_WANT_DENTRY;
+	rhead->flags = cpu_to_le32(flags);
+	rhead->num_fwd = req->r_num_fwd;
+	rhead->num_retry = req->r_attempts - 1;
+	rhead->ino = 0;
+
+	dout(" r_locked_dir = %p\n", req->r_locked_dir);
+	return 0;
+}
+
+/*
+ * send request, or put it on the appropriate wait list.
+ */
+static int __do_request(struct ceph_mds_client *mdsc,
+			struct ceph_mds_request *req)
+{
+	struct ceph_mds_session *session = NULL;
+	int mds = -1;
+	int err = -EAGAIN;
+
+	if (req->r_err || req->r_got_result) {
+		if (req->r_aborted)
+			__unregister_request(mdsc, req);
+		goto out;
+	}
+
+	if (req->r_timeout &&
+	    time_after_eq(jiffies, req->r_started + req->r_timeout)) {
+		dout("do_request timed out\n");
+		err = -EIO;
+		goto finish;
+	}
+
+	put_request_session(req);
+
+	mds = __choose_mds(mdsc, req);
+	if (mds < 0 ||
+	    ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
+		dout("do_request no mds or not active, waiting for map\n");
+		list_add(&req->r_wait, &mdsc->waiting_for_map);
+		goto out;
+	}
+
+	/* get, open session */
+	session = __ceph_lookup_mds_session(mdsc, mds);
+	if (!session) {
+		session = register_session(mdsc, mds);
+		if (IS_ERR(session)) {
+			err = PTR_ERR(session);
+			goto finish;
+		}
+	}
+	req->r_session = get_session(session);
+
+	dout("do_request mds%d session %p state %s\n", mds, session,
+	     ceph_session_state_name(session->s_state));
+	if (session->s_state != CEPH_MDS_SESSION_OPEN &&
+	    session->s_state != CEPH_MDS_SESSION_HUNG) {
+		if (session->s_state == CEPH_MDS_SESSION_NEW ||
+		    session->s_state == CEPH_MDS_SESSION_CLOSING)
+			__open_session(mdsc, session);
+		list_add(&req->r_wait, &session->s_waiting);
+		goto out_session;
+	}
+
+	/* send request */
+	req->r_resend_mds = -1;   /* forget any previous mds hint */
+
+	if (req->r_request_started == 0)   /* note request start time */
+		req->r_request_started = jiffies;
+
+	err = __prepare_send_request(mdsc, req, mds, false);
+	if (!err) {
+		ceph_msg_get(req->r_request);
+		ceph_con_send(&session->s_con, req->r_request);
+	}
+
+out_session:
+	ceph_put_mds_session(session);
+out:
+	return err;
+
+finish:
+	req->r_err = err;
+	complete_request(mdsc, req);
+	goto out;
+}
+
+/*
+ * called under mdsc->mutex
+ */
+static void __wake_requests(struct ceph_mds_client *mdsc,
+			    struct list_head *head)
+{
+	struct ceph_mds_request *req;
+	LIST_HEAD(tmp_list);
+
+	list_splice_init(head, &tmp_list);
+
+	while (!list_empty(&tmp_list)) {
+		req = list_entry(tmp_list.next,
+				 struct ceph_mds_request, r_wait);
+		list_del_init(&req->r_wait);
+		dout(" wake request %p tid %llu\n", req, req->r_tid);
+		__do_request(mdsc, req);
+	}
+}
+
+/*
+ * Wake up threads with requests pending for @mds, so that they can
+ * resubmit their requests to a possibly different mds.
+ */
+static void kick_requests(struct ceph_mds_client *mdsc, int mds)
+{
+	struct ceph_mds_request *req;
+	struct rb_node *p = rb_first(&mdsc->request_tree);
+
+	dout("kick_requests mds%d\n", mds);
+	while (p) {
+		req = rb_entry(p, struct ceph_mds_request, r_node);
+		p = rb_next(p);
+		if (req->r_got_unsafe)
+			continue;
+		if (req->r_attempts > 0)
+			continue; /* only new requests */
+		if (req->r_session &&
+		    req->r_session->s_mds == mds) {
+			dout(" kicking tid %llu\n", req->r_tid);
+			list_del_init(&req->r_wait);
+			__do_request(mdsc, req);
+		}
+	}
+}
+
+void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
+			      struct ceph_mds_request *req)
+{
+	dout("submit_request on %p\n", req);
+	mutex_lock(&mdsc->mutex);
+	__register_request(mdsc, req, NULL);
+	__do_request(mdsc, req);
+	mutex_unlock(&mdsc->mutex);
+}
+
+/*
+ * Synchrously perform an mds request.  Take care of all of the
+ * session setup, forwarding, retry details.
+ */
+int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
+			 struct inode *dir,
+			 struct ceph_mds_request *req)
+{
+	int err;
+
+	dout("do_request on %p\n", req);
+
+	/* take CAP_PIN refs for r_inode, r_locked_dir, r_old_dentry */
+	if (req->r_inode)
+		ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
+	if (req->r_locked_dir)
+		ceph_get_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
+	if (req->r_old_dentry_dir)
+		ceph_get_cap_refs(ceph_inode(req->r_old_dentry_dir),
+				  CEPH_CAP_PIN);
+
+	/* issue */
+	mutex_lock(&mdsc->mutex);
+	__register_request(mdsc, req, dir);
+	__do_request(mdsc, req);
+
+	if (req->r_err) {
+		err = req->r_err;
+		__unregister_request(mdsc, req);
+		dout("do_request early error %d\n", err);
+		goto out;
+	}
+
+	/* wait */
+	mutex_unlock(&mdsc->mutex);
+	dout("do_request waiting\n");
+	if (req->r_timeout) {
+		err = (long)wait_for_completion_killable_timeout(
+			&req->r_completion, req->r_timeout);
+		if (err == 0)
+			err = -EIO;
+	} else if (req->r_wait_for_completion) {
+		err = req->r_wait_for_completion(mdsc, req);
+	} else {
+		err = wait_for_completion_killable(&req->r_completion);
+	}
+	dout("do_request waited, got %d\n", err);
+	mutex_lock(&mdsc->mutex);
+
+	/* only abort if we didn't race with a real reply */
+	if (req->r_got_result) {
+		err = le32_to_cpu(req->r_reply_info.head->result);
+	} else if (err < 0) {
+		dout("aborted request %lld with %d\n", req->r_tid, err);
+
+		/*
+		 * ensure we aren't running concurrently with
+		 * ceph_fill_trace or ceph_readdir_prepopulate, which
+		 * rely on locks (dir mutex) held by our caller.
+		 */
+		mutex_lock(&req->r_fill_mutex);
+		req->r_err = err;
+		req->r_aborted = true;
+		mutex_unlock(&req->r_fill_mutex);
+
+		if (req->r_locked_dir &&
+		    (req->r_op & CEPH_MDS_OP_WRITE))
+			ceph_invalidate_dir_request(req);
+	} else {
+		err = req->r_err;
+	}
+
+out:
+	mutex_unlock(&mdsc->mutex);
+	dout("do_request %p done, result %d\n", req, err);
+	return err;
+}
+
+/*
+ * Invalidate dir's completeness, dentry lease state on an aborted MDS
+ * namespace request.
+ */
+void ceph_invalidate_dir_request(struct ceph_mds_request *req)
+{
+	struct inode *inode = req->r_locked_dir;
+
+	dout("invalidate_dir_request %p (complete, lease(s))\n", inode);
+
+	ceph_dir_clear_complete(inode);
+	if (req->r_dentry)
+		ceph_invalidate_dentry_lease(req->r_dentry);
+	if (req->r_old_dentry)
+		ceph_invalidate_dentry_lease(req->r_old_dentry);
+}
+
+/*
+ * Handle mds reply.
+ *
+ * We take the session mutex and parse and process the reply immediately.
+ * This preserves the logical ordering of replies, capabilities, etc., sent
+ * by the MDS as they are applied to our local cache.
+ */
+static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
+{
+	struct ceph_mds_client *mdsc = session->s_mdsc;
+	struct ceph_mds_request *req;
+	struct ceph_mds_reply_head *head = msg->front.iov_base;
+	struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
+	struct ceph_snap_realm *realm;
+	u64 tid;
+	int err, result;
+	int mds = session->s_mds;
+
+	if (msg->front.iov_len < sizeof(*head)) {
+		pr_err("mdsc_handle_reply got corrupt (short) reply\n");
+		ceph_msg_dump(msg);
+		return;
+	}
+
+	/* get request, session */
+	tid = le64_to_cpu(msg->hdr.tid);
+	mutex_lock(&mdsc->mutex);
+	req = __lookup_request(mdsc, tid);
+	if (!req) {
+		dout("handle_reply on unknown tid %llu\n", tid);
+		mutex_unlock(&mdsc->mutex);
+		return;
+	}
+	dout("handle_reply %p\n", req);
+
+	/* correct session? */
+	if (req->r_session != session) {
+		pr_err("mdsc_handle_reply got %llu on session mds%d"
+		       " not mds%d\n", tid, session->s_mds,
+		       req->r_session ? req->r_session->s_mds : -1);
+		mutex_unlock(&mdsc->mutex);
+		goto out;
+	}
+
+	/* dup? */
+	if ((req->r_got_unsafe && !head->safe) ||
+	    (req->r_got_safe && head->safe)) {
+		pr_warn("got a dup %s reply on %llu from mds%d\n",
+			   head->safe ? "safe" : "unsafe", tid, mds);
+		mutex_unlock(&mdsc->mutex);
+		goto out;
+	}
+	if (req->r_got_safe && !head->safe) {
+		pr_warn("got unsafe after safe on %llu from mds%d\n",
+			   tid, mds);
+		mutex_unlock(&mdsc->mutex);
+		goto out;
+	}
+
+	result = le32_to_cpu(head->result);
+
+	/*
+	 * Handle an ESTALE
+	 * if we're not talking to the authority, send to them
+	 * if the authority has changed while we weren't looking,
+	 * send to new authority
+	 * Otherwise we just have to return an ESTALE
+	 */
+	if (result == -ESTALE) {
+		dout("got ESTALE on request %llu", req->r_tid);
+		req->r_resend_mds = -1;
+		if (req->r_direct_mode != USE_AUTH_MDS) {
+			dout("not using auth, setting for that now");
+			req->r_direct_mode = USE_AUTH_MDS;
+			__do_request(mdsc, req);
+			mutex_unlock(&mdsc->mutex);
+			goto out;
+		} else  {
+			int mds = __choose_mds(mdsc, req);
+			if (mds >= 0 && mds != req->r_session->s_mds) {
+				dout("but auth changed, so resending");
+				__do_request(mdsc, req);
+				mutex_unlock(&mdsc->mutex);
+				goto out;
+			}
+		}
+		dout("have to return ESTALE on request %llu", req->r_tid);
+	}
+
+
+	if (head->safe) {
+		req->r_got_safe = true;
+		__unregister_request(mdsc, req);
+
+		if (req->r_got_unsafe) {
+			/*
+			 * We already handled the unsafe response, now do the
+			 * cleanup.  No need to examine the response; the MDS
+			 * doesn't include any result info in the safe
+			 * response.  And even if it did, there is nothing
+			 * useful we could do with a revised return value.
+			 */
+			dout("got safe reply %llu, mds%d\n", tid, mds);
+			list_del_init(&req->r_unsafe_item);
+
+			/* last unsafe request during umount? */
+			if (mdsc->stopping && !__get_oldest_req(mdsc))
+				complete_all(&mdsc->safe_umount_waiters);
+			mutex_unlock(&mdsc->mutex);
+			goto out;
+		}
+	} else {
+		req->r_got_unsafe = true;
+		list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
+	}
+
+	dout("handle_reply tid %lld result %d\n", tid, result);
+	rinfo = &req->r_reply_info;
+	err = parse_reply_info(msg, rinfo, session->s_con.peer_features);
+	mutex_unlock(&mdsc->mutex);
+
+	mutex_lock(&session->s_mutex);
+	if (err < 0) {
+		pr_err("mdsc_handle_reply got corrupt reply mds%d(tid:%lld)\n", mds, tid);
+		ceph_msg_dump(msg);
+		goto out_err;
+	}
+
+	/* snap trace */
+	realm = NULL;
+	if (rinfo->snapblob_len) {
+		down_write(&mdsc->snap_rwsem);
+		ceph_update_snap_trace(mdsc, rinfo->snapblob,
+				rinfo->snapblob + rinfo->snapblob_len,
+				le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP,
+				&realm);
+		downgrade_write(&mdsc->snap_rwsem);
+	} else {
+		down_read(&mdsc->snap_rwsem);
+	}
+
+	/* insert trace into our cache */
+	mutex_lock(&req->r_fill_mutex);
+	err = ceph_fill_trace(mdsc->fsc->sb, req, req->r_session);
+	if (err == 0) {
+		if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
+				    req->r_op == CEPH_MDS_OP_LSSNAP))
+			ceph_readdir_prepopulate(req, req->r_session);
+		ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
+	}
+	mutex_unlock(&req->r_fill_mutex);
+
+	up_read(&mdsc->snap_rwsem);
+	if (realm)
+		ceph_put_snap_realm(mdsc, realm);
+out_err:
+	mutex_lock(&mdsc->mutex);
+	if (!req->r_aborted) {
+		if (err) {
+			req->r_err = err;
+		} else {
+			req->r_reply = msg;
+			ceph_msg_get(msg);
+			req->r_got_result = true;
+		}
+	} else {
+		dout("reply arrived after request %lld was aborted\n", tid);
+	}
+	mutex_unlock(&mdsc->mutex);
+
+	ceph_add_cap_releases(mdsc, req->r_session);
+	mutex_unlock(&session->s_mutex);
+
+	/* kick calling process */
+	complete_request(mdsc, req);
+out:
+	ceph_mdsc_put_request(req);
+	return;
+}
+
+
+
+/*
+ * handle mds notification that our request has been forwarded.
+ */
+static void handle_forward(struct ceph_mds_client *mdsc,
+			   struct ceph_mds_session *session,
+			   struct ceph_msg *msg)
+{
+	struct ceph_mds_request *req;
+	u64 tid = le64_to_cpu(msg->hdr.tid);
+	u32 next_mds;
+	u32 fwd_seq;
+	int err = -EINVAL;
+	void *p = msg->front.iov_base;
+	void *end = p + msg->front.iov_len;
+
+	ceph_decode_need(&p, end, 2*sizeof(u32), bad);
+	next_mds = ceph_decode_32(&p);
+	fwd_seq = ceph_decode_32(&p);
+
+	mutex_lock(&mdsc->mutex);
+	req = __lookup_request(mdsc, tid);
+	if (!req) {
+		dout("forward tid %llu to mds%d - req dne\n", tid, next_mds);
+		goto out;  /* dup reply? */
+	}
+
+	if (req->r_aborted) {
+		dout("forward tid %llu aborted, unregistering\n", tid);
+		__unregister_request(mdsc, req);
+	} else if (fwd_seq <= req->r_num_fwd) {
+		dout("forward tid %llu to mds%d - old seq %d <= %d\n",
+		     tid, next_mds, req->r_num_fwd, fwd_seq);
+	} else {
+		/* resend. forward race not possible; mds would drop */
+		dout("forward tid %llu to mds%d (we resend)\n", tid, next_mds);
+		BUG_ON(req->r_err);
+		BUG_ON(req->r_got_result);
+		req->r_attempts = 0;
+		req->r_num_fwd = fwd_seq;
+		req->r_resend_mds = next_mds;
+		put_request_session(req);
+		__do_request(mdsc, req);
+	}
+	ceph_mdsc_put_request(req);
+out:
+	mutex_unlock(&mdsc->mutex);
+	return;
+
+bad:
+	pr_err("mdsc_handle_forward decode error err=%d\n", err);
+}
+
+/*
+ * handle a mds session control message
+ */
+static void handle_session(struct ceph_mds_session *session,
+			   struct ceph_msg *msg)
+{
+	struct ceph_mds_client *mdsc = session->s_mdsc;
+	u32 op;
+	u64 seq;
+	int mds = session->s_mds;
+	struct ceph_mds_session_head *h = msg->front.iov_base;
+	int wake = 0;
+
+	/* decode */
+	if (msg->front.iov_len != sizeof(*h))
+		goto bad;
+	op = le32_to_cpu(h->op);
+	seq = le64_to_cpu(h->seq);
+
+	mutex_lock(&mdsc->mutex);
+	if (op == CEPH_SESSION_CLOSE)
+		__unregister_session(mdsc, session);
+	/* FIXME: this ttl calculation is generous */
+	session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
+	mutex_unlock(&mdsc->mutex);
+
+	mutex_lock(&session->s_mutex);
+
+	dout("handle_session mds%d %s %p state %s seq %llu\n",
+	     mds, ceph_session_op_name(op), session,
+	     ceph_session_state_name(session->s_state), seq);
+
+	if (session->s_state == CEPH_MDS_SESSION_HUNG) {
+		session->s_state = CEPH_MDS_SESSION_OPEN;
+		pr_info("mds%d came back\n", session->s_mds);
+	}
+
+	switch (op) {
+	case CEPH_SESSION_OPEN:
+		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
+			pr_info("mds%d reconnect success\n", session->s_mds);
+		session->s_state = CEPH_MDS_SESSION_OPEN;
+		renewed_caps(mdsc, session, 0);
+		wake = 1;
+		if (mdsc->stopping)
+			__close_session(mdsc, session);
+		break;
+
+	case CEPH_SESSION_RENEWCAPS:
+		if (session->s_renew_seq == seq)
+			renewed_caps(mdsc, session, 1);
+		break;
+
+	case CEPH_SESSION_CLOSE:
+		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
+			pr_info("mds%d reconnect denied\n", session->s_mds);
+		cleanup_session_requests(mdsc, session);
+		remove_session_caps(session);
+		wake = 2; /* for good measure */
+		wake_up_all(&mdsc->session_close_wq);
+		break;
+
+	case CEPH_SESSION_STALE:
+		pr_info("mds%d caps went stale, renewing\n",
+			session->s_mds);
+		spin_lock(&session->s_gen_ttl_lock);
+		session->s_cap_gen++;
+		session->s_cap_ttl = jiffies - 1;
+		spin_unlock(&session->s_gen_ttl_lock);
+		send_renew_caps(mdsc, session);
+		break;
+
+	case CEPH_SESSION_RECALL_STATE:
+		trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
+		break;
+
+	case CEPH_SESSION_FLUSHMSG:
+		send_flushmsg_ack(mdsc, session, seq);
+		break;
+
+	case CEPH_SESSION_FORCE_RO:
+		dout("force_session_readonly %p\n", session);
+		spin_lock(&session->s_cap_lock);
+		session->s_readonly = true;
+		spin_unlock(&session->s_cap_lock);
+		wake_up_session_caps(session, 0);
+		break;
+
+	default:
+		pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
+		WARN_ON(1);
+	}
+
+	mutex_unlock(&session->s_mutex);
+	if (wake) {
+		mutex_lock(&mdsc->mutex);
+		__wake_requests(mdsc, &session->s_waiting);
+		if (wake == 2)
+			kick_requests(mdsc, mds);
+		mutex_unlock(&mdsc->mutex);
+	}
+	return;
+
+bad:
+	pr_err("mdsc_handle_session corrupt message mds%d len %d\n", mds,
+	       (int)msg->front.iov_len);
+	ceph_msg_dump(msg);
+	return;
+}
+
+
+/*
+ * called under session->mutex.
+ */
+static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
+				   struct ceph_mds_session *session)
+{
+	struct ceph_mds_request *req, *nreq;
+	struct rb_node *p;
+	int err;
+
+	dout("replay_unsafe_requests mds%d\n", session->s_mds);
+
+	mutex_lock(&mdsc->mutex);
+	list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item) {
+		err = __prepare_send_request(mdsc, req, session->s_mds, true);
+		if (!err) {
+			ceph_msg_get(req->r_request);
+			ceph_con_send(&session->s_con, req->r_request);
+		}
+	}
+
+	/*
+	 * also re-send old requests when MDS enters reconnect stage. So that MDS
+	 * can process completed request in clientreplay stage.
+	 */
+	p = rb_first(&mdsc->request_tree);
+	while (p) {
+		req = rb_entry(p, struct ceph_mds_request, r_node);
+		p = rb_next(p);
+		if (req->r_got_unsafe)
+			continue;
+		if (req->r_attempts == 0)
+			continue; /* only old requests */
+		if (req->r_session &&
+		    req->r_session->s_mds == session->s_mds) {
+			err = __prepare_send_request(mdsc, req,
+						     session->s_mds, true);
+			if (!err) {
+				ceph_msg_get(req->r_request);
+				ceph_con_send(&session->s_con, req->r_request);
+			}
+		}
+	}
+	mutex_unlock(&mdsc->mutex);
+}
+
+/*
+ * Encode information about a cap for a reconnect with the MDS.
+ */
+static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
+			  void *arg)
+{
+	union {
+		struct ceph_mds_cap_reconnect v2;
+		struct ceph_mds_cap_reconnect_v1 v1;
+	} rec;
+	size_t reclen;
+	struct ceph_inode_info *ci;
+	struct ceph_reconnect_state *recon_state = arg;
+	struct ceph_pagelist *pagelist = recon_state->pagelist;
+	char *path;
+	int pathlen, err;
+	u64 pathbase;
+	struct dentry *dentry;
+
+	ci = cap->ci;
+
+	dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
+	     inode, ceph_vinop(inode), cap, cap->cap_id,
+	     ceph_cap_string(cap->issued));
+	err = ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
+	if (err)
+		return err;
+
+	dentry = d_find_alias(inode);
+	if (dentry) {
+		path = ceph_mdsc_build_path(dentry, &pathlen, &pathbase, 0);
+		if (IS_ERR(path)) {
+			err = PTR_ERR(path);
+			goto out_dput;
+		}
+	} else {
+		path = NULL;
+		pathlen = 0;
+	}
+	err = ceph_pagelist_encode_string(pagelist, path, pathlen);
+	if (err)
+		goto out_free;
+
+	spin_lock(&ci->i_ceph_lock);
+	cap->seq = 0;        /* reset cap seq */
+	cap->issue_seq = 0;  /* and issue_seq */
+	cap->mseq = 0;       /* and migrate_seq */
+	cap->cap_gen = cap->session->s_cap_gen;
+
+	if (recon_state->flock) {
+		rec.v2.cap_id = cpu_to_le64(cap->cap_id);
+		rec.v2.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
+		rec.v2.issued = cpu_to_le32(cap->issued);
+		rec.v2.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
+		rec.v2.pathbase = cpu_to_le64(pathbase);
+		rec.v2.flock_len = 0;
+		reclen = sizeof(rec.v2);
+	} else {
+		rec.v1.cap_id = cpu_to_le64(cap->cap_id);
+		rec.v1.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
+		rec.v1.issued = cpu_to_le32(cap->issued);
+		rec.v1.size = cpu_to_le64(inode->i_size);
+		ceph_encode_timespec(&rec.v1.mtime, &inode->i_mtime);
+		ceph_encode_timespec(&rec.v1.atime, &inode->i_atime);
+		rec.v1.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
+		rec.v1.pathbase = cpu_to_le64(pathbase);
+		reclen = sizeof(rec.v1);
+	}
+	spin_unlock(&ci->i_ceph_lock);
+
+	if (recon_state->flock) {
+		int num_fcntl_locks, num_flock_locks;
+		struct ceph_filelock *flocks;
+
+encode_again:
+		ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks);
+		flocks = kmalloc((num_fcntl_locks+num_flock_locks) *
+				 sizeof(struct ceph_filelock), GFP_NOFS);
+		if (!flocks) {
+			err = -ENOMEM;
+			goto out_free;
+		}
+		err = ceph_encode_locks_to_buffer(inode, flocks,
+						  num_fcntl_locks,
+						  num_flock_locks);
+		if (err) {
+			kfree(flocks);
+			if (err == -ENOSPC)
+				goto encode_again;
+			goto out_free;
+		}
+		/*
+		 * number of encoded locks is stable, so copy to pagelist
+		 */
+		rec.v2.flock_len = cpu_to_le32(2*sizeof(u32) +
+				    (num_fcntl_locks+num_flock_locks) *
+				    sizeof(struct ceph_filelock));
+		err = ceph_pagelist_append(pagelist, &rec, reclen);
+		if (!err)
+			err = ceph_locks_to_pagelist(flocks, pagelist,
+						     num_fcntl_locks,
+						     num_flock_locks);
+		kfree(flocks);
+	} else {
+		err = ceph_pagelist_append(pagelist, &rec, reclen);
+	}
+
+	recon_state->nr_caps++;
+out_free:
+	kfree(path);
+out_dput:
+	dput(dentry);
+	return err;
+}
+
+
+/*
+ * If an MDS fails and recovers, clients need to reconnect in order to
+ * reestablish shared state.  This includes all caps issued through
+ * this session _and_ the snap_realm hierarchy.  Because it's not
+ * clear which snap realms the mds cares about, we send everything we
+ * know about.. that ensures we'll then get any new info the
+ * recovering MDS might have.
+ *
+ * This is a relatively heavyweight operation, but it's rare.
+ *
+ * called with mdsc->mutex held.
+ */
+static void send_mds_reconnect(struct ceph_mds_client *mdsc,
+			       struct ceph_mds_session *session)
+{
+	struct ceph_msg *reply;
+	struct rb_node *p;
+	int mds = session->s_mds;
+	int err = -ENOMEM;
+	int s_nr_caps;
+	struct ceph_pagelist *pagelist;
+	struct ceph_reconnect_state recon_state;
+
+	pr_info("mds%d reconnect start\n", mds);
+
+	pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
+	if (!pagelist)
+		goto fail_nopagelist;
+	ceph_pagelist_init(pagelist);
+
+	reply = ceph_msg_new(CEPH_MSG_CLIENT_RECONNECT, 0, GFP_NOFS, false);
+	if (!reply)
+		goto fail_nomsg;
+
+	mutex_lock(&session->s_mutex);
+	session->s_state = CEPH_MDS_SESSION_RECONNECTING;
+	session->s_seq = 0;
+
+	dout("session %p state %s\n", session,
+	     ceph_session_state_name(session->s_state));
+
+	spin_lock(&session->s_gen_ttl_lock);
+	session->s_cap_gen++;
+	spin_unlock(&session->s_gen_ttl_lock);
+
+	spin_lock(&session->s_cap_lock);
+	/* don't know if session is readonly */
+	session->s_readonly = 0;
+	/*
+	 * notify __ceph_remove_cap() that we are composing cap reconnect.
+	 * If a cap get released before being added to the cap reconnect,
+	 * __ceph_remove_cap() should skip queuing cap release.
+	 */
+	session->s_cap_reconnect = 1;
+	/* drop old cap expires; we're about to reestablish that state */
+	discard_cap_releases(mdsc, session);
+	spin_unlock(&session->s_cap_lock);
+
+	/* trim unused caps to reduce MDS's cache rejoin time */
+	if (mdsc->fsc->sb->s_root)
+		shrink_dcache_parent(mdsc->fsc->sb->s_root);
+
+	ceph_con_close(&session->s_con);
+	ceph_con_open(&session->s_con,
+		      CEPH_ENTITY_TYPE_MDS, mds,
+		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
+
+	/* replay unsafe requests */
+	replay_unsafe_requests(mdsc, session);
+
+	down_read(&mdsc->snap_rwsem);
+
+	/* traverse this session's caps */
+	s_nr_caps = session->s_nr_caps;
+	err = ceph_pagelist_encode_32(pagelist, s_nr_caps);
+	if (err)
+		goto fail;
+
+	recon_state.nr_caps = 0;
+	recon_state.pagelist = pagelist;
+	recon_state.flock = session->s_con.peer_features & CEPH_FEATURE_FLOCK;
+	err = iterate_session_caps(session, encode_caps_cb, &recon_state);
+	if (err < 0)
+		goto fail;
+
+	spin_lock(&session->s_cap_lock);
+	session->s_cap_reconnect = 0;
+	spin_unlock(&session->s_cap_lock);
+
+	/*
+	 * snaprealms.  we provide mds with the ino, seq (version), and
+	 * parent for all of our realms.  If the mds has any newer info,
+	 * it will tell us.
+	 */
+	for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
+		struct ceph_snap_realm *realm =
+			rb_entry(p, struct ceph_snap_realm, node);
+		struct ceph_mds_snaprealm_reconnect sr_rec;
+
+		dout(" adding snap realm %llx seq %lld parent %llx\n",
+		     realm->ino, realm->seq, realm->parent_ino);
+		sr_rec.ino = cpu_to_le64(realm->ino);
+		sr_rec.seq = cpu_to_le64(realm->seq);
+		sr_rec.parent = cpu_to_le64(realm->parent_ino);
+		err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
+		if (err)
+			goto fail;
+	}
+
+	if (recon_state.flock)
+		reply->hdr.version = cpu_to_le16(2);
+
+	/* raced with cap release? */
+	if (s_nr_caps != recon_state.nr_caps) {
+		struct page *page = list_first_entry(&pagelist->head,
+						     struct page, lru);
+		__le32 *addr = kmap_atomic(page);
+		*addr = cpu_to_le32(recon_state.nr_caps);
+		kunmap_atomic(addr);
+	}
+
+	reply->hdr.data_len = cpu_to_le32(pagelist->length);
+	ceph_msg_data_add_pagelist(reply, pagelist);
+	ceph_con_send(&session->s_con, reply);
+
+	mutex_unlock(&session->s_mutex);
+
+	mutex_lock(&mdsc->mutex);
+	__wake_requests(mdsc, &session->s_waiting);
+	mutex_unlock(&mdsc->mutex);
+
+	up_read(&mdsc->snap_rwsem);
+	return;
+
+fail:
+	ceph_msg_put(reply);
+	up_read(&mdsc->snap_rwsem);
+	mutex_unlock(&session->s_mutex);
+fail_nomsg:
+	ceph_pagelist_release(pagelist);
+fail_nopagelist:
+	pr_err("error %d preparing reconnect for mds%d\n", err, mds);
+	return;
+}
+
+
+/*
+ * compare old and new mdsmaps, kicking requests
+ * and closing out old connections as necessary
+ *
+ * called under mdsc->mutex.
+ */
+static void check_new_map(struct ceph_mds_client *mdsc,
+			  struct ceph_mdsmap *newmap,
+			  struct ceph_mdsmap *oldmap)
+{
+	int i;
+	int oldstate, newstate;
+	struct ceph_mds_session *s;
+
+	dout("check_new_map new %u old %u\n",
+	     newmap->m_epoch, oldmap->m_epoch);
+
+	for (i = 0; i < oldmap->m_max_mds && i < mdsc->max_sessions; i++) {
+		if (mdsc->sessions[i] == NULL)
+			continue;
+		s = mdsc->sessions[i];
+		oldstate = ceph_mdsmap_get_state(oldmap, i);
+		newstate = ceph_mdsmap_get_state(newmap, i);
+
+		dout("check_new_map mds%d state %s%s -> %s%s (session %s)\n",
+		     i, ceph_mds_state_name(oldstate),
+		     ceph_mdsmap_is_laggy(oldmap, i) ? " (laggy)" : "",
+		     ceph_mds_state_name(newstate),
+		     ceph_mdsmap_is_laggy(newmap, i) ? " (laggy)" : "",
+		     ceph_session_state_name(s->s_state));
+
+		if (i >= newmap->m_max_mds ||
+		    memcmp(ceph_mdsmap_get_addr(oldmap, i),
+			   ceph_mdsmap_get_addr(newmap, i),
+			   sizeof(struct ceph_entity_addr))) {
+			if (s->s_state == CEPH_MDS_SESSION_OPENING) {
+				/* the session never opened, just close it
+				 * out now */
+				__wake_requests(mdsc, &s->s_waiting);
+				__unregister_session(mdsc, s);
+			} else {
+				/* just close it */
+				mutex_unlock(&mdsc->mutex);
+				mutex_lock(&s->s_mutex);
+				mutex_lock(&mdsc->mutex);
+				ceph_con_close(&s->s_con);
+				mutex_unlock(&s->s_mutex);
+				s->s_state = CEPH_MDS_SESSION_RESTARTING;
+			}
+		} else if (oldstate == newstate) {
+			continue;  /* nothing new with this mds */
+		}
+
+		/*
+		 * send reconnect?
+		 */
+		if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
+		    newstate >= CEPH_MDS_STATE_RECONNECT) {
+			mutex_unlock(&mdsc->mutex);
+			send_mds_reconnect(mdsc, s);
+			mutex_lock(&mdsc->mutex);
+		}
+
+		/*
+		 * kick request on any mds that has gone active.
+		 */
+		if (oldstate < CEPH_MDS_STATE_ACTIVE &&
+		    newstate >= CEPH_MDS_STATE_ACTIVE) {
+			if (oldstate != CEPH_MDS_STATE_CREATING &&
+			    oldstate != CEPH_MDS_STATE_STARTING)
+				pr_info("mds%d recovery completed\n", s->s_mds);
+			kick_requests(mdsc, i);
+			ceph_kick_flushing_caps(mdsc, s);
+			wake_up_session_caps(s, 1);
+		}
+	}
+
+	for (i = 0; i < newmap->m_max_mds && i < mdsc->max_sessions; i++) {
+		s = mdsc->sessions[i];
+		if (!s)
+			continue;
+		if (!ceph_mdsmap_is_laggy(newmap, i))
+			continue;
+		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
+		    s->s_state == CEPH_MDS_SESSION_HUNG ||
+		    s->s_state == CEPH_MDS_SESSION_CLOSING) {
+			dout(" connecting to export targets of laggy mds%d\n",
+			     i);
+			__open_export_target_sessions(mdsc, s);
+		}
+	}
+}
+
+
+
+/*
+ * leases
+ */
+
+/*
+ * caller must hold session s_mutex, dentry->d_lock
+ */
+void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
+{
+	struct ceph_dentry_info *di = ceph_dentry(dentry);
+
+	ceph_put_mds_session(di->lease_session);
+	di->lease_session = NULL;
+}
+
+static void handle_lease(struct ceph_mds_client *mdsc,
+			 struct ceph_mds_session *session,
+			 struct ceph_msg *msg)
+{
+	struct super_block *sb = mdsc->fsc->sb;
+	struct inode *inode;
+	struct dentry *parent, *dentry;
+	struct ceph_dentry_info *di;
+	int mds = session->s_mds;
+	struct ceph_mds_lease *h = msg->front.iov_base;
+	u32 seq;
+	struct ceph_vino vino;
+	struct qstr dname;
+	int release = 0;
+
+	dout("handle_lease from mds%d\n", mds);
+
+	/* decode */
+	if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
+		goto bad;
+	vino.ino = le64_to_cpu(h->ino);
+	vino.snap = CEPH_NOSNAP;
+	seq = le32_to_cpu(h->seq);
+	dname.name = (void *)h + sizeof(*h) + sizeof(u32);
+	dname.len = msg->front.iov_len - sizeof(*h) - sizeof(u32);
+	if (dname.len != get_unaligned_le32(h+1))
+		goto bad;
+
+	/* lookup inode */
+	inode = ceph_find_inode(sb, vino);
+	dout("handle_lease %s, ino %llx %p %.*s\n",
+	     ceph_lease_op_name(h->action), vino.ino, inode,
+	     dname.len, dname.name);
+
+	mutex_lock(&session->s_mutex);
+	session->s_seq++;
+
+	if (inode == NULL) {
+		dout("handle_lease no inode %llx\n", vino.ino);
+		goto release;
+	}
+
+	/* dentry */
+	parent = d_find_alias(inode);
+	if (!parent) {
+		dout("no parent dentry on inode %p\n", inode);
+		WARN_ON(1);
+		goto release;  /* hrm... */
+	}
+	dname.hash = full_name_hash(dname.name, dname.len);
+	dentry = d_lookup(parent, &dname);
+	dput(parent);
+	if (!dentry)
+		goto release;
+
+	spin_lock(&dentry->d_lock);
+	di = ceph_dentry(dentry);
+	switch (h->action) {
+	case CEPH_MDS_LEASE_REVOKE:
+		if (di->lease_session == session) {
+			if (ceph_seq_cmp(di->lease_seq, seq) > 0)
+				h->seq = cpu_to_le32(di->lease_seq);
+			__ceph_mdsc_drop_dentry_lease(dentry);
+		}
+		release = 1;
+		break;
+
+	case CEPH_MDS_LEASE_RENEW:
+		if (di->lease_session == session &&
+		    di->lease_gen == session->s_cap_gen &&
+		    di->lease_renew_from &&
+		    di->lease_renew_after == 0) {
+			unsigned long duration =
+				msecs_to_jiffies(le32_to_cpu(h->duration_ms));
+
+			di->lease_seq = seq;
+			dentry->d_time = di->lease_renew_from + duration;
+			di->lease_renew_after = di->lease_renew_from +
+				(duration >> 1);
+			di->lease_renew_from = 0;
+		}
+		break;
+	}
+	spin_unlock(&dentry->d_lock);
+	dput(dentry);
+
+	if (!release)
+		goto out;
+
+release:
+	/* let's just reuse the same message */
+	h->action = CEPH_MDS_LEASE_REVOKE_ACK;
+	ceph_msg_get(msg);
+	ceph_con_send(&session->s_con, msg);
+
+out:
+	iput(inode);
+	mutex_unlock(&session->s_mutex);
+	return;
+
+bad:
+	pr_err("corrupt lease message\n");
+	ceph_msg_dump(msg);
+}
+
+void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
+			      struct inode *inode,
+			      struct dentry *dentry, char action,
+			      u32 seq)
+{
+	struct ceph_msg *msg;
+	struct ceph_mds_lease *lease;
+	int len = sizeof(*lease) + sizeof(u32);
+	int dnamelen = 0;
+
+	dout("lease_send_msg inode %p dentry %p %s to mds%d\n",
+	     inode, dentry, ceph_lease_op_name(action), session->s_mds);
+	dnamelen = dentry->d_name.len;
+	len += dnamelen;
+
+	msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, GFP_NOFS, false);
+	if (!msg)
+		return;
+	lease = msg->front.iov_base;
+	lease->action = action;
+	lease->ino = cpu_to_le64(ceph_vino(inode).ino);
+	lease->first = lease->last = cpu_to_le64(ceph_vino(inode).snap);
+	lease->seq = cpu_to_le32(seq);
+	put_unaligned_le32(dnamelen, lease + 1);
+	memcpy((void *)(lease + 1) + 4, dentry->d_name.name, dnamelen);
+
+	/*
+	 * if this is a preemptive lease RELEASE, no need to
+	 * flush request stream, since the actual request will
+	 * soon follow.
+	 */
+	msg->more_to_follow = (action == CEPH_MDS_LEASE_RELEASE);
+
+	ceph_con_send(&session->s_con, msg);
+}
+
+/*
+ * Preemptively release a lease we expect to invalidate anyway.
+ * Pass @inode always, @dentry is optional.
+ */
+void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc, struct inode *inode,
+			     struct dentry *dentry)
+{
+	struct ceph_dentry_info *di;
+	struct ceph_mds_session *session;
+	u32 seq;
+
+	BUG_ON(inode == NULL);
+	BUG_ON(dentry == NULL);
+
+	/* is dentry lease valid? */
+	spin_lock(&dentry->d_lock);
+	di = ceph_dentry(dentry);
+	if (!di || !di->lease_session ||
+	    di->lease_session->s_mds < 0 ||
+	    di->lease_gen != di->lease_session->s_cap_gen ||
+	    !time_before(jiffies, dentry->d_time)) {
+		dout("lease_release inode %p dentry %p -- "
+		     "no lease\n",
+		     inode, dentry);
+		spin_unlock(&dentry->d_lock);
+		return;
+	}
+
+	/* we do have a lease on this dentry; note mds and seq */
+	session = ceph_get_mds_session(di->lease_session);
+	seq = di->lease_seq;
+	__ceph_mdsc_drop_dentry_lease(dentry);
+	spin_unlock(&dentry->d_lock);
+
+	dout("lease_release inode %p dentry %p to mds%d\n",
+	     inode, dentry, session->s_mds);
+	ceph_mdsc_lease_send_msg(session, inode, dentry,
+				 CEPH_MDS_LEASE_RELEASE, seq);
+	ceph_put_mds_session(session);
+}
+
+/*
+ * drop all leases (and dentry refs) in preparation for umount
+ */
+static void drop_leases(struct ceph_mds_client *mdsc)
+{
+	int i;
+
+	dout("drop_leases\n");
+	mutex_lock(&mdsc->mutex);
+	for (i = 0; i < mdsc->max_sessions; i++) {
+		struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
+		if (!s)
+			continue;
+		mutex_unlock(&mdsc->mutex);
+		mutex_lock(&s->s_mutex);
+		mutex_unlock(&s->s_mutex);
+		ceph_put_mds_session(s);
+		mutex_lock(&mdsc->mutex);
+	}
+	mutex_unlock(&mdsc->mutex);
+}
+
+
+
+/*
+ * delayed work -- periodically trim expired leases, renew caps with mds
+ */
+static void schedule_delayed(struct ceph_mds_client *mdsc)
+{
+	int delay = 5;
+	unsigned hz = round_jiffies_relative(HZ * delay);
+	schedule_delayed_work(&mdsc->delayed_work, hz);
+}
+
+static void delayed_work(struct work_struct *work)
+{
+	int i;
+	struct ceph_mds_client *mdsc =
+		container_of(work, struct ceph_mds_client, delayed_work.work);
+	int renew_interval;
+	int renew_caps;
+
+	dout("mdsc delayed_work\n");
+	ceph_check_delayed_caps(mdsc);
+
+	mutex_lock(&mdsc->mutex);
+	renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
+	renew_caps = time_after_eq(jiffies, HZ*renew_interval +
+				   mdsc->last_renew_caps);
+	if (renew_caps)
+		mdsc->last_renew_caps = jiffies;
+
+	for (i = 0; i < mdsc->max_sessions; i++) {
+		struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
+		if (s == NULL)
+			continue;
+		if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
+			dout("resending session close request for mds%d\n",
+			     s->s_mds);
+			request_close_session(mdsc, s);
+			ceph_put_mds_session(s);
+			continue;
+		}
+		if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
+			if (s->s_state == CEPH_MDS_SESSION_OPEN) {
+				s->s_state = CEPH_MDS_SESSION_HUNG;
+				pr_info("mds%d hung\n", s->s_mds);
+			}
+		}
+		if (s->s_state < CEPH_MDS_SESSION_OPEN) {
+			/* this mds is failed or recovering, just wait */
+			ceph_put_mds_session(s);
+			continue;
+		}
+		mutex_unlock(&mdsc->mutex);
+
+		mutex_lock(&s->s_mutex);
+		if (renew_caps)
+			send_renew_caps(mdsc, s);
+		else
+			ceph_con_keepalive(&s->s_con);
+		ceph_add_cap_releases(mdsc, s);
+		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
+		    s->s_state == CEPH_MDS_SESSION_HUNG)
+			ceph_send_cap_releases(mdsc, s);
+		mutex_unlock(&s->s_mutex);
+		ceph_put_mds_session(s);
+
+		mutex_lock(&mdsc->mutex);
+	}
+	mutex_unlock(&mdsc->mutex);
+
+	schedule_delayed(mdsc);
+}
+
+int ceph_mdsc_init(struct ceph_fs_client *fsc)
+
+{
+	struct ceph_mds_client *mdsc;
+
+	mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
+	if (!mdsc)
+		return -ENOMEM;
+	mdsc->fsc = fsc;
+	fsc->mdsc = mdsc;
+	mutex_init(&mdsc->mutex);
+	mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
+	if (mdsc->mdsmap == NULL) {
+		kfree(mdsc);
+		return -ENOMEM;
+	}
+
+	init_completion(&mdsc->safe_umount_waiters);
+	init_waitqueue_head(&mdsc->session_close_wq);
+	INIT_LIST_HEAD(&mdsc->waiting_for_map);
+	mdsc->sessions = NULL;
+	atomic_set(&mdsc->num_sessions, 0);
+	mdsc->max_sessions = 0;
+	mdsc->stopping = 0;
+	init_rwsem(&mdsc->snap_rwsem);
+	mdsc->snap_realms = RB_ROOT;
+	INIT_LIST_HEAD(&mdsc->snap_empty);
+	spin_lock_init(&mdsc->snap_empty_lock);
+	mdsc->last_tid = 0;
+	mdsc->request_tree = RB_ROOT;
+	INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
+	mdsc->last_renew_caps = jiffies;
+	INIT_LIST_HEAD(&mdsc->cap_delay_list);
+	spin_lock_init(&mdsc->cap_delay_lock);
+	INIT_LIST_HEAD(&mdsc->snap_flush_list);
+	spin_lock_init(&mdsc->snap_flush_lock);
+	mdsc->cap_flush_seq = 0;
+	INIT_LIST_HEAD(&mdsc->cap_dirty);
+	INIT_LIST_HEAD(&mdsc->cap_dirty_migrating);
+	mdsc->num_cap_flushing = 0;
+	spin_lock_init(&mdsc->cap_dirty_lock);
+	init_waitqueue_head(&mdsc->cap_flushing_wq);
+	spin_lock_init(&mdsc->dentry_lru_lock);
+	INIT_LIST_HEAD(&mdsc->dentry_lru);
+
+	ceph_caps_init(mdsc);
+	ceph_adjust_min_caps(mdsc, fsc->min_caps);
+
+	return 0;
+}
+
+/*
+ * Wait for safe replies on open mds requests.  If we time out, drop
+ * all requests from the tree to avoid dangling dentry refs.
+ */
+static void wait_requests(struct ceph_mds_client *mdsc)
+{
+	struct ceph_mds_request *req;
+	struct ceph_fs_client *fsc = mdsc->fsc;
+
+	mutex_lock(&mdsc->mutex);
+	if (__get_oldest_req(mdsc)) {
+		mutex_unlock(&mdsc->mutex);
+
+		dout("wait_requests waiting for requests\n");
+		wait_for_completion_timeout(&mdsc->safe_umount_waiters,
+				    fsc->client->options->mount_timeout * HZ);
+
+		/* tear down remaining requests */
+		mutex_lock(&mdsc->mutex);
+		while ((req = __get_oldest_req(mdsc))) {
+			dout("wait_requests timed out on tid %llu\n",
+			     req->r_tid);
+			__unregister_request(mdsc, req);
+		}
+	}
+	mutex_unlock(&mdsc->mutex);
+	dout("wait_requests done\n");
+}
+
+/*
+ * called before mount is ro, and before dentries are torn down.
+ * (hmm, does this still race with new lookups?)
+ */
+void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
+{
+	dout("pre_umount\n");
+	mdsc->stopping = 1;
+
+	drop_leases(mdsc);
+	ceph_flush_dirty_caps(mdsc);
+	wait_requests(mdsc);
+
+	/*
+	 * wait for reply handlers to drop their request refs and
+	 * their inode/dcache refs
+	 */
+	ceph_msgr_flush();
+}
+
+/*
+ * wait for all write mds requests to flush.
+ */
+static void wait_unsafe_requests(struct ceph_mds_client *mdsc, u64 want_tid)
+{
+	struct ceph_mds_request *req = NULL, *nextreq;
+	struct rb_node *n;
+
+	mutex_lock(&mdsc->mutex);
+	dout("wait_unsafe_requests want %lld\n", want_tid);
+restart:
+	req = __get_oldest_req(mdsc);
+	while (req && req->r_tid <= want_tid) {
+		/* find next request */
+		n = rb_next(&req->r_node);
+		if (n)
+			nextreq = rb_entry(n, struct ceph_mds_request, r_node);
+		else
+			nextreq = NULL;
+		if ((req->r_op & CEPH_MDS_OP_WRITE)) {
+			/* write op */
+			ceph_mdsc_get_request(req);
+			if (nextreq)
+				ceph_mdsc_get_request(nextreq);
+			mutex_unlock(&mdsc->mutex);
+			dout("wait_unsafe_requests  wait on %llu (want %llu)\n",
+			     req->r_tid, want_tid);
+			wait_for_completion(&req->r_safe_completion);
+			mutex_lock(&mdsc->mutex);
+			ceph_mdsc_put_request(req);
+			if (!nextreq)
+				break;  /* next dne before, so we're done! */
+			if (RB_EMPTY_NODE(&nextreq->r_node)) {
+				/* next request was removed from tree */
+				ceph_mdsc_put_request(nextreq);
+				goto restart;
+			}
+			ceph_mdsc_put_request(nextreq);  /* won't go away */
+		}
+		req = nextreq;
+	}
+	mutex_unlock(&mdsc->mutex);
+	dout("wait_unsafe_requests done\n");
+}
+
+void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
+{
+	u64 want_tid, want_flush;
+
+	if (mdsc->fsc->mount_state == CEPH_MOUNT_SHUTDOWN)
+		return;
+
+	dout("sync\n");
+	mutex_lock(&mdsc->mutex);
+	want_tid = mdsc->last_tid;
+	mutex_unlock(&mdsc->mutex);
+
+	ceph_flush_dirty_caps(mdsc);
+	spin_lock(&mdsc->cap_dirty_lock);
+	want_flush = mdsc->cap_flush_seq;
+	spin_unlock(&mdsc->cap_dirty_lock);
+
+	dout("sync want tid %lld flush_seq %lld\n", want_tid, want_flush);
+
+	wait_unsafe_requests(mdsc, want_tid);
+	wait_caps_flush(mdsc, want_flush);
+}
+
+/*
+ * true if all sessions are closed, or we force unmount
+ */
+static bool done_closing_sessions(struct ceph_mds_client *mdsc)
+{
+	if (mdsc->fsc->mount_state == CEPH_MOUNT_SHUTDOWN)
+		return true;
+	return atomic_read(&mdsc->num_sessions) == 0;
+}
+
+/*
+ * called after sb is ro.
+ */
+void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
+{
+	struct ceph_mds_session *session;
+	int i;
+	struct ceph_fs_client *fsc = mdsc->fsc;
+	unsigned long timeout = fsc->client->options->mount_timeout * HZ;
+
+	dout("close_sessions\n");
+
+	/* close sessions */
+	mutex_lock(&mdsc->mutex);
+	for (i = 0; i < mdsc->max_sessions; i++) {
+		session = __ceph_lookup_mds_session(mdsc, i);
+		if (!session)
+			continue;
+		mutex_unlock(&mdsc->mutex);
+		mutex_lock(&session->s_mutex);
+		__close_session(mdsc, session);
+		mutex_unlock(&session->s_mutex);
+		ceph_put_mds_session(session);
+		mutex_lock(&mdsc->mutex);
+	}
+	mutex_unlock(&mdsc->mutex);
+
+	dout("waiting for sessions to close\n");
+	wait_event_timeout(mdsc->session_close_wq, done_closing_sessions(mdsc),
+			   timeout);
+
+	/* tear down remaining sessions */
+	mutex_lock(&mdsc->mutex);
+	for (i = 0; i < mdsc->max_sessions; i++) {
+		if (mdsc->sessions[i]) {
+			session = get_session(mdsc->sessions[i]);
+			__unregister_session(mdsc, session);
+			mutex_unlock(&mdsc->mutex);
+			mutex_lock(&session->s_mutex);
+			remove_session_caps(session);
+			mutex_unlock(&session->s_mutex);
+			ceph_put_mds_session(session);
+			mutex_lock(&mdsc->mutex);
+		}
+	}
+	WARN_ON(!list_empty(&mdsc->cap_delay_list));
+	mutex_unlock(&mdsc->mutex);
+
+	ceph_cleanup_empty_realms(mdsc);
+
+	cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
+
+	dout("stopped\n");
+}
+
+static void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
+{
+	dout("stop\n");
+	cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
+	if (mdsc->mdsmap)
+		ceph_mdsmap_destroy(mdsc->mdsmap);
+	kfree(mdsc->sessions);
+	ceph_caps_finalize(mdsc);
+}
+
+void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
+{
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+
+	dout("mdsc_destroy %p\n", mdsc);
+	ceph_mdsc_stop(mdsc);
+
+	/* flush out any connection work with references to us */
+	ceph_msgr_flush();
+
+	fsc->mdsc = NULL;
+	kfree(mdsc);
+	dout("mdsc_destroy %p done\n", mdsc);
+}
+
+
+/*
+ * handle mds map update.
+ */
+void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
+{
+	u32 epoch;
+	u32 maplen;
+	void *p = msg->front.iov_base;
+	void *end = p + msg->front.iov_len;
+	struct ceph_mdsmap *newmap, *oldmap;
+	struct ceph_fsid fsid;
+	int err = -EINVAL;
+
+	ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
+	ceph_decode_copy(&p, &fsid, sizeof(fsid));
+	if (ceph_check_fsid(mdsc->fsc->client, &fsid) < 0)
+		return;
+	epoch = ceph_decode_32(&p);
+	maplen = ceph_decode_32(&p);
+	dout("handle_map epoch %u len %d\n", epoch, (int)maplen);
+
+	/* do we need it? */
+	ceph_monc_got_mdsmap(&mdsc->fsc->client->monc, epoch);
+	mutex_lock(&mdsc->mutex);
+	if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
+		dout("handle_map epoch %u <= our %u\n",
+		     epoch, mdsc->mdsmap->m_epoch);
+		mutex_unlock(&mdsc->mutex);
+		return;
+	}
+
+	newmap = ceph_mdsmap_decode(&p, end);
+	if (IS_ERR(newmap)) {
+		err = PTR_ERR(newmap);
+		goto bad_unlock;
+	}
+
+	/* swap into place */
+	if (mdsc->mdsmap) {
+		oldmap = mdsc->mdsmap;
+		mdsc->mdsmap = newmap;
+		check_new_map(mdsc, newmap, oldmap);
+		ceph_mdsmap_destroy(oldmap);
+	} else {
+		mdsc->mdsmap = newmap;  /* first mds map */
+	}
+	mdsc->fsc->sb->s_maxbytes = mdsc->mdsmap->m_max_file_size;
+
+	__wake_requests(mdsc, &mdsc->waiting_for_map);
+
+	mutex_unlock(&mdsc->mutex);
+	schedule_delayed(mdsc);
+	return;
+
+bad_unlock:
+	mutex_unlock(&mdsc->mutex);
+bad:
+	pr_err("error decoding mdsmap %d\n", err);
+	return;
+}
+
+static struct ceph_connection *con_get(struct ceph_connection *con)
+{
+	struct ceph_mds_session *s = con->private;
+
+	if (get_session(s)) {
+		dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref));
+		return con;
+	}
+	dout("mdsc con_get %p FAIL\n", s);
+	return NULL;
+}
+
+static void con_put(struct ceph_connection *con)
+{
+	struct ceph_mds_session *s = con->private;
+
+	dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref) - 1);
+	ceph_put_mds_session(s);
+}
+
+/*
+ * if the client is unresponsive for long enough, the mds will kill
+ * the session entirely.
+ */
+static void peer_reset(struct ceph_connection *con)
+{
+	struct ceph_mds_session *s = con->private;
+	struct ceph_mds_client *mdsc = s->s_mdsc;
+
+	pr_warn("mds%d closed our session\n", s->s_mds);
+	send_mds_reconnect(mdsc, s);
+}
+
+static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
+{
+	struct ceph_mds_session *s = con->private;
+	struct ceph_mds_client *mdsc = s->s_mdsc;
+	int type = le16_to_cpu(msg->hdr.type);
+
+	mutex_lock(&mdsc->mutex);
+	if (__verify_registered_session(mdsc, s) < 0) {
+		mutex_unlock(&mdsc->mutex);
+		goto out;
+	}
+	mutex_unlock(&mdsc->mutex);
+
+	switch (type) {
+	case CEPH_MSG_MDS_MAP:
+		ceph_mdsc_handle_map(mdsc, msg);
+		break;
+	case CEPH_MSG_CLIENT_SESSION:
+		handle_session(s, msg);
+		break;
+	case CEPH_MSG_CLIENT_REPLY:
+		handle_reply(s, msg);
+		break;
+	case CEPH_MSG_CLIENT_REQUEST_FORWARD:
+		handle_forward(mdsc, s, msg);
+		break;
+	case CEPH_MSG_CLIENT_CAPS:
+		ceph_handle_caps(s, msg);
+		break;
+	case CEPH_MSG_CLIENT_SNAP:
+		ceph_handle_snap(mdsc, s, msg);
+		break;
+	case CEPH_MSG_CLIENT_LEASE:
+		handle_lease(mdsc, s, msg);
+		break;
+
+	default:
+		pr_err("received unknown message type %d %s\n", type,
+		       ceph_msg_type_name(type));
+	}
+out:
+	ceph_msg_put(msg);
+}
+
+/*
+ * authentication
+ */
+
+/*
+ * Note: returned pointer is the address of a structure that's
+ * managed separately.  Caller must *not* attempt to free it.
+ */
+static struct ceph_auth_handshake *get_authorizer(struct ceph_connection *con,
+					int *proto, int force_new)
+{
+	struct ceph_mds_session *s = con->private;
+	struct ceph_mds_client *mdsc = s->s_mdsc;
+	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
+	struct ceph_auth_handshake *auth = &s->s_auth;
+
+	if (force_new && auth->authorizer) {
+		ceph_auth_destroy_authorizer(ac, auth->authorizer);
+		auth->authorizer = NULL;
+	}
+	if (!auth->authorizer) {
+		int ret = ceph_auth_create_authorizer(ac, CEPH_ENTITY_TYPE_MDS,
+						      auth);
+		if (ret)
+			return ERR_PTR(ret);
+	} else {
+		int ret = ceph_auth_update_authorizer(ac, CEPH_ENTITY_TYPE_MDS,
+						      auth);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+	*proto = ac->protocol;
+
+	return auth;
+}
+
+
+static int verify_authorizer_reply(struct ceph_connection *con, int len)
+{
+	struct ceph_mds_session *s = con->private;
+	struct ceph_mds_client *mdsc = s->s_mdsc;
+	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
+
+	return ceph_auth_verify_authorizer_reply(ac, s->s_auth.authorizer, len);
+}
+
+static int invalidate_authorizer(struct ceph_connection *con)
+{
+	struct ceph_mds_session *s = con->private;
+	struct ceph_mds_client *mdsc = s->s_mdsc;
+	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
+
+	ceph_auth_invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
+
+	return ceph_monc_validate_auth(&mdsc->fsc->client->monc);
+}
+
+static struct ceph_msg *mds_alloc_msg(struct ceph_connection *con,
+				struct ceph_msg_header *hdr, int *skip)
+{
+	struct ceph_msg *msg;
+	int type = (int) le16_to_cpu(hdr->type);
+	int front_len = (int) le32_to_cpu(hdr->front_len);
+
+	if (con->in_msg)
+		return con->in_msg;
+
+	*skip = 0;
+	msg = ceph_msg_new(type, front_len, GFP_NOFS, false);
+	if (!msg) {
+		pr_err("unable to allocate msg type %d len %d\n",
+		       type, front_len);
+		return NULL;
+	}
+
+	return msg;
+}
+
+static int sign_message(struct ceph_connection *con, struct ceph_msg *msg)
+{
+       struct ceph_mds_session *s = con->private;
+       struct ceph_auth_handshake *auth = &s->s_auth;
+       return ceph_auth_sign_message(auth, msg);
+}
+
+static int check_message_signature(struct ceph_connection *con, struct ceph_msg *msg)
+{
+       struct ceph_mds_session *s = con->private;
+       struct ceph_auth_handshake *auth = &s->s_auth;
+       return ceph_auth_check_message_signature(auth, msg);
+}
+
+static const struct ceph_connection_operations mds_con_ops = {
+	.get = con_get,
+	.put = con_put,
+	.dispatch = dispatch,
+	.get_authorizer = get_authorizer,
+	.verify_authorizer_reply = verify_authorizer_reply,
+	.invalidate_authorizer = invalidate_authorizer,
+	.peer_reset = peer_reset,
+	.alloc_msg = mds_alloc_msg,
+	.sign_message = sign_message,
+	.check_message_signature = check_message_signature,
+};
+
+/* eof */
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
new file mode 100644
index 000000000..1875b5d98
--- /dev/null
+++ b/fs/ceph/mds_client.h
@@ -0,0 +1,406 @@
+#ifndef _FS_CEPH_MDS_CLIENT_H
+#define _FS_CEPH_MDS_CLIENT_H
+
+#include <linux/completion.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+
+#include <linux/ceph/types.h>
+#include <linux/ceph/messenger.h>
+#include <linux/ceph/mdsmap.h>
+#include <linux/ceph/auth.h>
+
+/*
+ * Some lock dependencies:
+ *
+ * session->s_mutex
+ *         mdsc->mutex
+ *
+ *         mdsc->snap_rwsem
+ *
+ *         ci->i_ceph_lock
+ *                 mdsc->snap_flush_lock
+ *                 mdsc->cap_delay_lock
+ *
+ */
+
+struct ceph_fs_client;
+struct ceph_cap;
+
+/*
+ * parsed info about a single inode.  pointers are into the encoded
+ * on-wire structures within the mds reply message payload.
+ */
+struct ceph_mds_reply_info_in {
+	struct ceph_mds_reply_inode *in;
+	struct ceph_dir_layout dir_layout;
+	u32 symlink_len;
+	char *symlink;
+	u32 xattr_len;
+	char *xattr_data;
+	u64 inline_version;
+	u32 inline_len;
+	char *inline_data;
+};
+
+/*
+ * parsed info about an mds reply, including information about
+ * either: 1) the target inode and/or its parent directory and dentry,
+ * and directory contents (for readdir results), or
+ * 2) the file range lock info (for fcntl F_GETLK results).
+ */
+struct ceph_mds_reply_info_parsed {
+	struct ceph_mds_reply_head    *head;
+
+	/* trace */
+	struct ceph_mds_reply_info_in diri, targeti;
+	struct ceph_mds_reply_dirfrag *dirfrag;
+	char                          *dname;
+	u32                           dname_len;
+	struct ceph_mds_reply_lease   *dlease;
+
+	/* extra */
+	union {
+		/* for fcntl F_GETLK results */
+		struct ceph_filelock *filelock_reply;
+
+		/* for readdir results */
+		struct {
+			struct ceph_mds_reply_dirfrag *dir_dir;
+			size_t			      dir_buf_size;
+			int                           dir_nr;
+			char                          **dir_dname;
+			u32                           *dir_dname_len;
+			struct ceph_mds_reply_lease   **dir_dlease;
+			struct ceph_mds_reply_info_in *dir_in;
+			u8                            dir_complete, dir_end;
+		};
+
+		/* for create results */
+		struct {
+			bool has_create_ino;
+			u64 ino;
+		};
+	};
+
+	/* encoded blob describing snapshot contexts for certain
+	   operations (e.g., open) */
+	void *snapblob;
+	int snapblob_len;
+};
+
+
+/*
+ * cap releases are batched and sent to the MDS en masse.
+ */
+#define CEPH_CAPS_PER_RELEASE ((PAGE_CACHE_SIZE -			\
+				sizeof(struct ceph_mds_cap_release)) /	\
+			       sizeof(struct ceph_mds_cap_item))
+
+
+/*
+ * state associated with each MDS<->client session
+ */
+enum {
+	CEPH_MDS_SESSION_NEW = 1,
+	CEPH_MDS_SESSION_OPENING = 2,
+	CEPH_MDS_SESSION_OPEN = 3,
+	CEPH_MDS_SESSION_HUNG = 4,
+	CEPH_MDS_SESSION_CLOSING = 5,
+	CEPH_MDS_SESSION_RESTARTING = 6,
+	CEPH_MDS_SESSION_RECONNECTING = 7,
+};
+
+struct ceph_mds_session {
+	struct ceph_mds_client *s_mdsc;
+	int               s_mds;
+	int               s_state;
+	unsigned long     s_ttl;      /* time until mds kills us */
+	u64               s_seq;      /* incoming msg seq # */
+	struct mutex      s_mutex;    /* serialize session messages */
+
+	struct ceph_connection s_con;
+
+	struct ceph_auth_handshake s_auth;
+
+	/* protected by s_gen_ttl_lock */
+	spinlock_t        s_gen_ttl_lock;
+	u32               s_cap_gen;  /* inc each time we get mds stale msg */
+	unsigned long     s_cap_ttl;  /* when session caps expire */
+
+	/* protected by s_cap_lock */
+	spinlock_t        s_cap_lock;
+	struct list_head  s_caps;     /* all caps issued by this session */
+	int               s_nr_caps, s_trim_caps;
+	int               s_num_cap_releases;
+	int		  s_cap_reconnect;
+	int		  s_readonly;
+	struct list_head  s_cap_releases; /* waiting cap_release messages */
+	struct list_head  s_cap_releases_done; /* ready to send */
+	struct ceph_cap  *s_cap_iterator;
+
+	/* protected by mutex */
+	struct list_head  s_cap_flushing;     /* inodes w/ flushing caps */
+	struct list_head  s_cap_snaps_flushing;
+	unsigned long     s_renew_requested; /* last time we sent a renew req */
+	u64               s_renew_seq;
+
+	atomic_t          s_ref;
+	struct list_head  s_waiting;  /* waiting requests */
+	struct list_head  s_unsafe;   /* unsafe requests */
+};
+
+/*
+ * modes of choosing which MDS to send a request to
+ */
+enum {
+	USE_ANY_MDS,
+	USE_RANDOM_MDS,
+	USE_AUTH_MDS,   /* prefer authoritative mds for this metadata item */
+};
+
+struct ceph_mds_request;
+struct ceph_mds_client;
+
+/*
+ * request completion callback
+ */
+typedef void (*ceph_mds_request_callback_t) (struct ceph_mds_client *mdsc,
+					     struct ceph_mds_request *req);
+/*
+ * wait for request completion callback
+ */
+typedef int (*ceph_mds_request_wait_callback_t) (struct ceph_mds_client *mdsc,
+						 struct ceph_mds_request *req);
+
+/*
+ * an in-flight mds request
+ */
+struct ceph_mds_request {
+	u64 r_tid;                   /* transaction id */
+	struct rb_node r_node;
+	struct ceph_mds_client *r_mdsc;
+
+	int r_op;                    /* mds op code */
+
+	/* operation on what? */
+	struct inode *r_inode;              /* arg1 */
+	struct dentry *r_dentry;            /* arg1 */
+	struct dentry *r_old_dentry;        /* arg2: rename from or link from */
+	struct inode *r_old_dentry_dir;     /* arg2: old dentry's parent dir */
+	char *r_path1, *r_path2;
+	struct ceph_vino r_ino1, r_ino2;
+
+	struct inode *r_locked_dir; /* dir (if any) i_mutex locked by vfs */
+	struct inode *r_target_inode;       /* resulting inode */
+
+	struct mutex r_fill_mutex;
+
+	union ceph_mds_request_args r_args;
+	int r_fmode;        /* file mode, if expecting cap */
+	kuid_t r_uid;
+	kgid_t r_gid;
+	struct timespec r_stamp;
+
+	/* for choosing which mds to send this request to */
+	int r_direct_mode;
+	u32 r_direct_hash;      /* choose dir frag based on this dentry hash */
+	bool r_direct_is_hash;  /* true if r_direct_hash is valid */
+
+	/* data payload is used for xattr ops */
+	struct ceph_pagelist *r_pagelist;
+
+	/* what caps shall we drop? */
+	int r_inode_drop, r_inode_unless;
+	int r_dentry_drop, r_dentry_unless;
+	int r_old_dentry_drop, r_old_dentry_unless;
+	struct inode *r_old_inode;
+	int r_old_inode_drop, r_old_inode_unless;
+
+	struct ceph_msg  *r_request;  /* original request */
+	int r_request_release_offset;
+	struct ceph_msg  *r_reply;
+	struct ceph_mds_reply_info_parsed r_reply_info;
+	struct page *r_locked_page;
+	int r_err;
+	bool r_aborted;
+
+	unsigned long r_timeout;  /* optional.  jiffies */
+	unsigned long r_started;  /* start time to measure timeout against */
+	unsigned long r_request_started; /* start time for mds request only,
+					    used to measure lease durations */
+
+	/* link unsafe requests to parent directory, for fsync */
+	struct inode	*r_unsafe_dir;
+	struct list_head r_unsafe_dir_item;
+
+	struct ceph_mds_session *r_session;
+
+	int               r_attempts;   /* resend attempts */
+	int               r_num_fwd;    /* number of forward attempts */
+	int               r_resend_mds; /* mds to resend to next, if any*/
+	u32               r_sent_on_mseq; /* cap mseq request was sent at*/
+
+	struct kref       r_kref;
+	struct list_head  r_wait;
+	struct completion r_completion;
+	struct completion r_safe_completion;
+	ceph_mds_request_callback_t r_callback;
+	ceph_mds_request_wait_callback_t r_wait_for_completion;
+	struct list_head  r_unsafe_item;  /* per-session unsafe list item */
+	bool		  r_got_unsafe, r_got_safe, r_got_result;
+
+	bool              r_did_prepopulate;
+	u32               r_readdir_offset;
+
+	struct ceph_cap_reservation r_caps_reservation;
+	int r_num_caps;
+};
+
+/*
+ * mds client state
+ */
+struct ceph_mds_client {
+	struct ceph_fs_client  *fsc;
+	struct mutex            mutex;         /* all nested structures */
+
+	struct ceph_mdsmap      *mdsmap;
+	struct completion       safe_umount_waiters;
+	wait_queue_head_t       session_close_wq;
+	struct list_head        waiting_for_map;
+
+	struct ceph_mds_session **sessions;    /* NULL for mds if no session */
+	atomic_t		num_sessions;
+	int                     max_sessions;  /* len of s_mds_sessions */
+	int                     stopping;      /* true if shutting down */
+
+	/*
+	 * snap_rwsem will cover cap linkage into snaprealms, and
+	 * realm snap contexts.  (later, we can do per-realm snap
+	 * contexts locks..)  the empty list contains realms with no
+	 * references (implying they contain no inodes with caps) that
+	 * should be destroyed.
+	 */
+	struct rw_semaphore     snap_rwsem;
+	struct rb_root          snap_realms;
+	struct list_head        snap_empty;
+	spinlock_t              snap_empty_lock;  /* protect snap_empty */
+
+	u64                    last_tid;      /* most recent mds request */
+	struct rb_root         request_tree;  /* pending mds requests */
+	struct delayed_work    delayed_work;  /* delayed work */
+	unsigned long    last_renew_caps;  /* last time we renewed our caps */
+	struct list_head cap_delay_list;   /* caps with delayed release */
+	spinlock_t       cap_delay_lock;   /* protects cap_delay_list */
+	struct list_head snap_flush_list;  /* cap_snaps ready to flush */
+	spinlock_t       snap_flush_lock;
+
+	u64               cap_flush_seq;
+	struct list_head  cap_dirty;        /* inodes with dirty caps */
+	struct list_head  cap_dirty_migrating; /* ...that are migration... */
+	int               num_cap_flushing; /* # caps we are flushing */
+	spinlock_t        cap_dirty_lock;   /* protects above items */
+	wait_queue_head_t cap_flushing_wq;
+
+	/*
+	 * Cap reservations
+	 *
+	 * Maintain a global pool of preallocated struct ceph_caps, referenced
+	 * by struct ceph_caps_reservations.  This ensures that we preallocate
+	 * memory needed to successfully process an MDS response.  (If an MDS
+	 * sends us cap information and we fail to process it, we will have
+	 * problems due to the client and MDS being out of sync.)
+	 *
+	 * Reservations are 'owned' by a ceph_cap_reservation context.
+	 */
+	spinlock_t	caps_list_lock;
+	struct		list_head caps_list; /* unused (reserved or
+						unreserved) */
+	int		caps_total_count;    /* total caps allocated */
+	int		caps_use_count;      /* in use */
+	int		caps_reserve_count;  /* unused, reserved */
+	int		caps_avail_count;    /* unused, unreserved */
+	int		caps_min_count;      /* keep at least this many
+						(unreserved) */
+	spinlock_t	  dentry_lru_lock;
+	struct list_head  dentry_lru;
+	int		  num_dentry;
+};
+
+extern const char *ceph_mds_op_name(int op);
+
+extern struct ceph_mds_session *
+__ceph_lookup_mds_session(struct ceph_mds_client *, int mds);
+
+static inline struct ceph_mds_session *
+ceph_get_mds_session(struct ceph_mds_session *s)
+{
+	atomic_inc(&s->s_ref);
+	return s;
+}
+
+extern const char *ceph_session_state_name(int s);
+
+extern void ceph_put_mds_session(struct ceph_mds_session *s);
+
+extern int ceph_send_msg_mds(struct ceph_mds_client *mdsc,
+			     struct ceph_msg *msg, int mds);
+
+extern int ceph_mdsc_init(struct ceph_fs_client *fsc);
+extern void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc);
+extern void ceph_mdsc_destroy(struct ceph_fs_client *fsc);
+
+extern void ceph_mdsc_sync(struct ceph_mds_client *mdsc);
+
+extern void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc,
+				    struct inode *inode,
+				    struct dentry *dn);
+
+extern void ceph_invalidate_dir_request(struct ceph_mds_request *req);
+extern int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
+					   struct inode *dir);
+extern struct ceph_mds_request *
+ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode);
+extern void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
+				     struct ceph_mds_request *req);
+extern int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
+				struct inode *dir,
+				struct ceph_mds_request *req);
+static inline void ceph_mdsc_get_request(struct ceph_mds_request *req)
+{
+	kref_get(&req->r_kref);
+}
+extern void ceph_mdsc_release_request(struct kref *kref);
+static inline void ceph_mdsc_put_request(struct ceph_mds_request *req)
+{
+	kref_put(&req->r_kref, ceph_mdsc_release_request);
+}
+
+extern int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
+				 struct ceph_mds_session *session);
+extern void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
+				   struct ceph_mds_session *session);
+
+extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);
+
+extern char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
+				  int stop_on_nosnap);
+
+extern void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry);
+extern void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
+				     struct inode *inode,
+				     struct dentry *dentry, char action,
+				     u32 seq);
+
+extern void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc,
+				 struct ceph_msg *msg);
+
+extern struct ceph_mds_session *
+ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target);
+extern void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
+					  struct ceph_mds_session *session);
+
+#endif
diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
new file mode 100644
index 000000000..261531e55
--- /dev/null
+++ b/fs/ceph/mdsmap.c
@@ -0,0 +1,189 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <linux/ceph/mdsmap.h>
+#include <linux/ceph/messenger.h>
+#include <linux/ceph/decode.h>
+
+#include "super.h"
+
+
+/*
+ * choose a random mds that is "up" (i.e. has a state > 0), or -1.
+ */
+int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m)
+{
+	int n = 0;
+	int i;
+
+	/* special case for one mds */
+	if (1 == m->m_max_mds && m->m_info[0].state > 0)
+		return 0;
+
+	/* count */
+	for (i = 0; i < m->m_max_mds; i++)
+		if (m->m_info[i].state > 0)
+			n++;
+	if (n == 0)
+		return -1;
+
+	/* pick */
+	n = prandom_u32() % n;
+	i = 0;
+	for (i = 0; n > 0; i++, n--)
+		while (m->m_info[i].state <= 0)
+			i++;
+
+	return i;
+}
+
+/*
+ * Decode an MDS map
+ *
+ * Ignore any fields we don't care about (there are quite a few of
+ * them).
+ */
+struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
+{
+	struct ceph_mdsmap *m;
+	const void *start = *p;
+	int i, j, n;
+	int err = -EINVAL;
+	u16 version;
+
+	m = kzalloc(sizeof(*m), GFP_NOFS);
+	if (m == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	ceph_decode_16_safe(p, end, version, bad);
+	if (version > 3) {
+		pr_warn("got mdsmap version %d > 3, failing", version);
+		goto bad;
+	}
+
+	ceph_decode_need(p, end, 8*sizeof(u32) + sizeof(u64), bad);
+	m->m_epoch = ceph_decode_32(p);
+	m->m_client_epoch = ceph_decode_32(p);
+	m->m_last_failure = ceph_decode_32(p);
+	m->m_root = ceph_decode_32(p);
+	m->m_session_timeout = ceph_decode_32(p);
+	m->m_session_autoclose = ceph_decode_32(p);
+	m->m_max_file_size = ceph_decode_64(p);
+	m->m_max_mds = ceph_decode_32(p);
+
+	m->m_info = kcalloc(m->m_max_mds, sizeof(*m->m_info), GFP_NOFS);
+	if (m->m_info == NULL)
+		goto badmem;
+
+	/* pick out active nodes from mds_info (state > 0) */
+	n = ceph_decode_32(p);
+	for (i = 0; i < n; i++) {
+		u64 global_id;
+		u32 namelen;
+		s32 mds, inc, state;
+		u64 state_seq;
+		u8 infoversion;
+		struct ceph_entity_addr addr;
+		u32 num_export_targets;
+		void *pexport_targets = NULL;
+		struct ceph_timespec laggy_since;
+		struct ceph_mds_info *info;
+
+		ceph_decode_need(p, end, sizeof(u64)*2 + 1 + sizeof(u32), bad);
+		global_id = ceph_decode_64(p);
+		infoversion = ceph_decode_8(p);
+		*p += sizeof(u64);
+		namelen = ceph_decode_32(p);  /* skip mds name */
+		*p += namelen;
+
+		ceph_decode_need(p, end,
+				 4*sizeof(u32) + sizeof(u64) +
+				 sizeof(addr) + sizeof(struct ceph_timespec),
+				 bad);
+		mds = ceph_decode_32(p);
+		inc = ceph_decode_32(p);
+		state = ceph_decode_32(p);
+		state_seq = ceph_decode_64(p);
+		ceph_decode_copy(p, &addr, sizeof(addr));
+		ceph_decode_addr(&addr);
+		ceph_decode_copy(p, &laggy_since, sizeof(laggy_since));
+		*p += sizeof(u32);
+		ceph_decode_32_safe(p, end, namelen, bad);
+		*p += namelen;
+		if (infoversion >= 2) {
+			ceph_decode_32_safe(p, end, num_export_targets, bad);
+			pexport_targets = *p;
+			*p += num_export_targets * sizeof(u32);
+		} else {
+			num_export_targets = 0;
+		}
+
+		dout("mdsmap_decode %d/%d %lld mds%d.%d %s %s\n",
+		     i+1, n, global_id, mds, inc,
+		     ceph_pr_addr(&addr.in_addr),
+		     ceph_mds_state_name(state));
+
+		if (mds < 0 || mds >= m->m_max_mds || state <= 0)
+			continue;
+
+		info = &m->m_info[mds];
+		info->global_id = global_id;
+		info->state = state;
+		info->addr = addr;
+		info->laggy = (laggy_since.tv_sec != 0 ||
+			       laggy_since.tv_nsec != 0);
+		info->num_export_targets = num_export_targets;
+		if (num_export_targets) {
+			info->export_targets = kcalloc(num_export_targets,
+						       sizeof(u32), GFP_NOFS);
+			if (info->export_targets == NULL)
+				goto badmem;
+			for (j = 0; j < num_export_targets; j++)
+				info->export_targets[j] =
+				       ceph_decode_32(&pexport_targets);
+		} else {
+			info->export_targets = NULL;
+		}
+	}
+
+	/* pg_pools */
+	ceph_decode_32_safe(p, end, n, bad);
+	m->m_num_data_pg_pools = n;
+	m->m_data_pg_pools = kcalloc(n, sizeof(u64), GFP_NOFS);
+	if (!m->m_data_pg_pools)
+		goto badmem;
+	ceph_decode_need(p, end, sizeof(u64)*(n+1), bad);
+	for (i = 0; i < n; i++)
+		m->m_data_pg_pools[i] = ceph_decode_64(p);
+	m->m_cas_pg_pool = ceph_decode_64(p);
+
+	/* ok, we don't care about the rest. */
+	dout("mdsmap_decode success epoch %u\n", m->m_epoch);
+	return m;
+
+badmem:
+	err = -ENOMEM;
+bad:
+	pr_err("corrupt mdsmap\n");
+	print_hex_dump(KERN_DEBUG, "mdsmap: ",
+		       DUMP_PREFIX_OFFSET, 16, 1,
+		       start, end - start, true);
+	ceph_mdsmap_destroy(m);
+	return ERR_PTR(err);
+}
+
+void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
+{
+	int i;
+
+	for (i = 0; i < m->m_max_mds; i++)
+		kfree(m->m_info[i].export_targets);
+	kfree(m->m_info);
+	kfree(m->m_data_pg_pools);
+	kfree(m);
+}
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
new file mode 100644
index 000000000..a97e39f09
--- /dev/null
+++ b/fs/ceph/snap.c
@@ -0,0 +1,977 @@
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/sort.h>
+#include <linux/slab.h>
+
+#include "super.h"
+#include "mds_client.h"
+
+#include <linux/ceph/decode.h>
+
+/*
+ * Snapshots in ceph are driven in large part by cooperation from the
+ * client.  In contrast to local file systems or file servers that
+ * implement snapshots at a single point in the system, ceph's
+ * distributed access to storage requires clients to help decide
+ * whether a write logically occurs before or after a recently created
+ * snapshot.
+ *
+ * This provides a perfect instantanous client-wide snapshot.  Between
+ * clients, however, snapshots may appear to be applied at slightly
+ * different points in time, depending on delays in delivering the
+ * snapshot notification.
+ *
+ * Snapshots are _not_ file system-wide.  Instead, each snapshot
+ * applies to the subdirectory nested beneath some directory.  This
+ * effectively divides the hierarchy into multiple "realms," where all
+ * of the files contained by each realm share the same set of
+ * snapshots.  An individual realm's snap set contains snapshots
+ * explicitly created on that realm, as well as any snaps in its
+ * parent's snap set _after_ the point at which the parent became it's
+ * parent (due to, say, a rename).  Similarly, snaps from prior parents
+ * during the time intervals during which they were the parent are included.
+ *
+ * The client is spared most of this detail, fortunately... it must only
+ * maintains a hierarchy of realms reflecting the current parent/child
+ * realm relationship, and for each realm has an explicit list of snaps
+ * inherited from prior parents.
+ *
+ * A snap_realm struct is maintained for realms containing every inode
+ * with an open cap in the system.  (The needed snap realm information is
+ * provided by the MDS whenever a cap is issued, i.e., on open.)  A 'seq'
+ * version number is used to ensure that as realm parameters change (new
+ * snapshot, new parent, etc.) the client's realm hierarchy is updated.
+ *
+ * The realm hierarchy drives the generation of a 'snap context' for each
+ * realm, which simply lists the resulting set of snaps for the realm.  This
+ * is attached to any writes sent to OSDs.
+ */
+/*
+ * Unfortunately error handling is a bit mixed here.  If we get a snap
+ * update, but don't have enough memory to update our realm hierarchy,
+ * it's not clear what we can do about it (besides complaining to the
+ * console).
+ */
+
+
+/*
+ * increase ref count for the realm
+ *
+ * caller must hold snap_rwsem for write.
+ */
+void ceph_get_snap_realm(struct ceph_mds_client *mdsc,
+			 struct ceph_snap_realm *realm)
+{
+	dout("get_realm %p %d -> %d\n", realm,
+	     atomic_read(&realm->nref), atomic_read(&realm->nref)+1);
+	/*
+	 * since we _only_ increment realm refs or empty the empty
+	 * list with snap_rwsem held, adjusting the empty list here is
+	 * safe.  we do need to protect against concurrent empty list
+	 * additions, however.
+	 */
+	if (atomic_inc_return(&realm->nref) == 1) {
+		spin_lock(&mdsc->snap_empty_lock);
+		list_del_init(&realm->empty_item);
+		spin_unlock(&mdsc->snap_empty_lock);
+	}
+}
+
+static void __insert_snap_realm(struct rb_root *root,
+				struct ceph_snap_realm *new)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
+	struct ceph_snap_realm *r = NULL;
+
+	while (*p) {
+		parent = *p;
+		r = rb_entry(parent, struct ceph_snap_realm, node);
+		if (new->ino < r->ino)
+			p = &(*p)->rb_left;
+		else if (new->ino > r->ino)
+			p = &(*p)->rb_right;
+		else
+			BUG();
+	}
+
+	rb_link_node(&new->node, parent, p);
+	rb_insert_color(&new->node, root);
+}
+
+/*
+ * create and get the realm rooted at @ino and bump its ref count.
+ *
+ * caller must hold snap_rwsem for write.
+ */
+static struct ceph_snap_realm *ceph_create_snap_realm(
+	struct ceph_mds_client *mdsc,
+	u64 ino)
+{
+	struct ceph_snap_realm *realm;
+
+	realm = kzalloc(sizeof(*realm), GFP_NOFS);
+	if (!realm)
+		return ERR_PTR(-ENOMEM);
+
+	atomic_set(&realm->nref, 1);    /* for caller */
+	realm->ino = ino;
+	INIT_LIST_HEAD(&realm->children);
+	INIT_LIST_HEAD(&realm->child_item);
+	INIT_LIST_HEAD(&realm->empty_item);
+	INIT_LIST_HEAD(&realm->dirty_item);
+	INIT_LIST_HEAD(&realm->inodes_with_caps);
+	spin_lock_init(&realm->inodes_with_caps_lock);
+	__insert_snap_realm(&mdsc->snap_realms, realm);
+	dout("create_snap_realm %llx %p\n", realm->ino, realm);
+	return realm;
+}
+
+/*
+ * lookup the realm rooted at @ino.
+ *
+ * caller must hold snap_rwsem for write.
+ */
+static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc,
+						   u64 ino)
+{
+	struct rb_node *n = mdsc->snap_realms.rb_node;
+	struct ceph_snap_realm *r;
+
+	while (n) {
+		r = rb_entry(n, struct ceph_snap_realm, node);
+		if (ino < r->ino)
+			n = n->rb_left;
+		else if (ino > r->ino)
+			n = n->rb_right;
+		else {
+			dout("lookup_snap_realm %llx %p\n", r->ino, r);
+			return r;
+		}
+	}
+	return NULL;
+}
+
+struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
+					       u64 ino)
+{
+	struct ceph_snap_realm *r;
+	r = __lookup_snap_realm(mdsc, ino);
+	if (r)
+		ceph_get_snap_realm(mdsc, r);
+	return r;
+}
+
+static void __put_snap_realm(struct ceph_mds_client *mdsc,
+			     struct ceph_snap_realm *realm);
+
+/*
+ * called with snap_rwsem (write)
+ */
+static void __destroy_snap_realm(struct ceph_mds_client *mdsc,
+				 struct ceph_snap_realm *realm)
+{
+	dout("__destroy_snap_realm %p %llx\n", realm, realm->ino);
+
+	rb_erase(&realm->node, &mdsc->snap_realms);
+
+	if (realm->parent) {
+		list_del_init(&realm->child_item);
+		__put_snap_realm(mdsc, realm->parent);
+	}
+
+	kfree(realm->prior_parent_snaps);
+	kfree(realm->snaps);
+	ceph_put_snap_context(realm->cached_context);
+	kfree(realm);
+}
+
+/*
+ * caller holds snap_rwsem (write)
+ */
+static void __put_snap_realm(struct ceph_mds_client *mdsc,
+			     struct ceph_snap_realm *realm)
+{
+	dout("__put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
+	     atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
+	if (atomic_dec_and_test(&realm->nref))
+		__destroy_snap_realm(mdsc, realm);
+}
+
+/*
+ * caller needn't hold any locks
+ */
+void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
+			 struct ceph_snap_realm *realm)
+{
+	dout("put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
+	     atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
+	if (!atomic_dec_and_test(&realm->nref))
+		return;
+
+	if (down_write_trylock(&mdsc->snap_rwsem)) {
+		__destroy_snap_realm(mdsc, realm);
+		up_write(&mdsc->snap_rwsem);
+	} else {
+		spin_lock(&mdsc->snap_empty_lock);
+		list_add(&realm->empty_item, &mdsc->snap_empty);
+		spin_unlock(&mdsc->snap_empty_lock);
+	}
+}
+
+/*
+ * Clean up any realms whose ref counts have dropped to zero.  Note
+ * that this does not include realms who were created but not yet
+ * used.
+ *
+ * Called under snap_rwsem (write)
+ */
+static void __cleanup_empty_realms(struct ceph_mds_client *mdsc)
+{
+	struct ceph_snap_realm *realm;
+
+	spin_lock(&mdsc->snap_empty_lock);
+	while (!list_empty(&mdsc->snap_empty)) {
+		realm = list_first_entry(&mdsc->snap_empty,
+				   struct ceph_snap_realm, empty_item);
+		list_del(&realm->empty_item);
+		spin_unlock(&mdsc->snap_empty_lock);
+		__destroy_snap_realm(mdsc, realm);
+		spin_lock(&mdsc->snap_empty_lock);
+	}
+	spin_unlock(&mdsc->snap_empty_lock);
+}
+
+void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc)
+{
+	down_write(&mdsc->snap_rwsem);
+	__cleanup_empty_realms(mdsc);
+	up_write(&mdsc->snap_rwsem);
+}
+
+/*
+ * adjust the parent realm of a given @realm.  adjust child list, and parent
+ * pointers, and ref counts appropriately.
+ *
+ * return true if parent was changed, 0 if unchanged, <0 on error.
+ *
+ * caller must hold snap_rwsem for write.
+ */
+static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc,
+				    struct ceph_snap_realm *realm,
+				    u64 parentino)
+{
+	struct ceph_snap_realm *parent;
+
+	if (realm->parent_ino == parentino)
+		return 0;
+
+	parent = ceph_lookup_snap_realm(mdsc, parentino);
+	if (!parent) {
+		parent = ceph_create_snap_realm(mdsc, parentino);
+		if (IS_ERR(parent))
+			return PTR_ERR(parent);
+	}
+	dout("adjust_snap_realm_parent %llx %p: %llx %p -> %llx %p\n",
+	     realm->ino, realm, realm->parent_ino, realm->parent,
+	     parentino, parent);
+	if (realm->parent) {
+		list_del_init(&realm->child_item);
+		ceph_put_snap_realm(mdsc, realm->parent);
+	}
+	realm->parent_ino = parentino;
+	realm->parent = parent;
+	list_add(&realm->child_item, &parent->children);
+	return 1;
+}
+
+
+static int cmpu64_rev(const void *a, const void *b)
+{
+	if (*(u64 *)a < *(u64 *)b)
+		return 1;
+	if (*(u64 *)a > *(u64 *)b)
+		return -1;
+	return 0;
+}
+
+
+static struct ceph_snap_context *empty_snapc;
+
+/*
+ * build the snap context for a given realm.
+ */
+static int build_snap_context(struct ceph_snap_realm *realm)
+{
+	struct ceph_snap_realm *parent = realm->parent;
+	struct ceph_snap_context *snapc;
+	int err = 0;
+	u32 num = realm->num_prior_parent_snaps + realm->num_snaps;
+
+	/*
+	 * build parent context, if it hasn't been built.
+	 * conservatively estimate that all parent snaps might be
+	 * included by us.
+	 */
+	if (parent) {
+		if (!parent->cached_context) {
+			err = build_snap_context(parent);
+			if (err)
+				goto fail;
+		}
+		num += parent->cached_context->num_snaps;
+	}
+
+	/* do i actually need to update?  not if my context seq
+	   matches realm seq, and my parents' does to.  (this works
+	   because we rebuild_snap_realms() works _downward_ in
+	   hierarchy after each update.) */
+	if (realm->cached_context &&
+	    realm->cached_context->seq == realm->seq &&
+	    (!parent ||
+	     realm->cached_context->seq >= parent->cached_context->seq)) {
+		dout("build_snap_context %llx %p: %p seq %lld (%u snaps)"
+		     " (unchanged)\n",
+		     realm->ino, realm, realm->cached_context,
+		     realm->cached_context->seq,
+		     (unsigned int) realm->cached_context->num_snaps);
+		return 0;
+	}
+
+	if (num == 0 && realm->seq == empty_snapc->seq) {
+		ceph_get_snap_context(empty_snapc);
+		snapc = empty_snapc;
+		goto done;
+	}
+
+	/* alloc new snap context */
+	err = -ENOMEM;
+	if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
+		goto fail;
+	snapc = ceph_create_snap_context(num, GFP_NOFS);
+	if (!snapc)
+		goto fail;
+
+	/* build (reverse sorted) snap vector */
+	num = 0;
+	snapc->seq = realm->seq;
+	if (parent) {
+		u32 i;
+
+		/* include any of parent's snaps occurring _after_ my
+		   parent became my parent */
+		for (i = 0; i < parent->cached_context->num_snaps; i++)
+			if (parent->cached_context->snaps[i] >=
+			    realm->parent_since)
+				snapc->snaps[num++] =
+					parent->cached_context->snaps[i];
+		if (parent->cached_context->seq > snapc->seq)
+			snapc->seq = parent->cached_context->seq;
+	}
+	memcpy(snapc->snaps + num, realm->snaps,
+	       sizeof(u64)*realm->num_snaps);
+	num += realm->num_snaps;
+	memcpy(snapc->snaps + num, realm->prior_parent_snaps,
+	       sizeof(u64)*realm->num_prior_parent_snaps);
+	num += realm->num_prior_parent_snaps;
+
+	sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL);
+	snapc->num_snaps = num;
+	dout("build_snap_context %llx %p: %p seq %lld (%u snaps)\n",
+	     realm->ino, realm, snapc, snapc->seq,
+	     (unsigned int) snapc->num_snaps);
+
+done:
+	ceph_put_snap_context(realm->cached_context);
+	realm->cached_context = snapc;
+	return 0;
+
+fail:
+	/*
+	 * if we fail, clear old (incorrect) cached_context... hopefully
+	 * we'll have better luck building it later
+	 */
+	if (realm->cached_context) {
+		ceph_put_snap_context(realm->cached_context);
+		realm->cached_context = NULL;
+	}
+	pr_err("build_snap_context %llx %p fail %d\n", realm->ino,
+	       realm, err);
+	return err;
+}
+
+/*
+ * rebuild snap context for the given realm and all of its children.
+ */
+static void rebuild_snap_realms(struct ceph_snap_realm *realm)
+{
+	struct ceph_snap_realm *child;
+
+	dout("rebuild_snap_realms %llx %p\n", realm->ino, realm);
+	build_snap_context(realm);
+
+	list_for_each_entry(child, &realm->children, child_item)
+		rebuild_snap_realms(child);
+}
+
+
+/*
+ * helper to allocate and decode an array of snapids.  free prior
+ * instance, if any.
+ */
+static int dup_array(u64 **dst, __le64 *src, u32 num)
+{
+	u32 i;
+
+	kfree(*dst);
+	if (num) {
+		*dst = kcalloc(num, sizeof(u64), GFP_NOFS);
+		if (!*dst)
+			return -ENOMEM;
+		for (i = 0; i < num; i++)
+			(*dst)[i] = get_unaligned_le64(src + i);
+	} else {
+		*dst = NULL;
+	}
+	return 0;
+}
+
+
+/*
+ * When a snapshot is applied, the size/mtime inode metadata is queued
+ * in a ceph_cap_snap (one for each snapshot) until writeback
+ * completes and the metadata can be flushed back to the MDS.
+ *
+ * However, if a (sync) write is currently in-progress when we apply
+ * the snapshot, we have to wait until the write succeeds or fails
+ * (and a final size/mtime is known).  In this case the
+ * cap_snap->writing = 1, and is said to be "pending."  When the write
+ * finishes, we __ceph_finish_cap_snap().
+ *
+ * Caller must hold snap_rwsem for read (i.e., the realm topology won't
+ * change).
+ */
+void ceph_queue_cap_snap(struct ceph_inode_info *ci)
+{
+	struct inode *inode = &ci->vfs_inode;
+	struct ceph_cap_snap *capsnap;
+	int used, dirty;
+
+	capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
+	if (!capsnap) {
+		pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode);
+		return;
+	}
+
+	spin_lock(&ci->i_ceph_lock);
+	used = __ceph_caps_used(ci);
+	dirty = __ceph_caps_dirty(ci);
+
+	/*
+	 * If there is a write in progress, treat that as a dirty Fw,
+	 * even though it hasn't completed yet; by the time we finish
+	 * up this capsnap it will be.
+	 */
+	if (used & CEPH_CAP_FILE_WR)
+		dirty |= CEPH_CAP_FILE_WR;
+
+	if (__ceph_have_pending_cap_snap(ci)) {
+		/* there is no point in queuing multiple "pending" cap_snaps,
+		   as no new writes are allowed to start when pending, so any
+		   writes in progress now were started before the previous
+		   cap_snap.  lucky us. */
+		dout("queue_cap_snap %p already pending\n", inode);
+		kfree(capsnap);
+	} else if (ci->i_snap_realm->cached_context == empty_snapc) {
+		dout("queue_cap_snap %p empty snapc\n", inode);
+		kfree(capsnap);
+	} else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL|
+			    CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) {
+		struct ceph_snap_context *snapc = ci->i_head_snapc;
+
+		/*
+		 * if we are a sync write, we may need to go to the snaprealm
+		 * to get the current snapc.
+		 */
+		if (!snapc)
+			snapc = ci->i_snap_realm->cached_context;
+
+		dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n",
+		     inode, capsnap, snapc, ceph_cap_string(dirty));
+		ihold(inode);
+
+		atomic_set(&capsnap->nref, 1);
+		capsnap->ci = ci;
+		INIT_LIST_HEAD(&capsnap->ci_item);
+		INIT_LIST_HEAD(&capsnap->flushing_item);
+
+		capsnap->follows = snapc->seq;
+		capsnap->issued = __ceph_caps_issued(ci, NULL);
+		capsnap->dirty = dirty;
+
+		capsnap->mode = inode->i_mode;
+		capsnap->uid = inode->i_uid;
+		capsnap->gid = inode->i_gid;
+
+		if (dirty & CEPH_CAP_XATTR_EXCL) {
+			__ceph_build_xattrs_blob(ci);
+			capsnap->xattr_blob =
+				ceph_buffer_get(ci->i_xattrs.blob);
+			capsnap->xattr_version = ci->i_xattrs.version;
+		} else {
+			capsnap->xattr_blob = NULL;
+			capsnap->xattr_version = 0;
+		}
+
+		capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
+
+		/* dirty page count moved from _head to this cap_snap;
+		   all subsequent writes page dirties occur _after_ this
+		   snapshot. */
+		capsnap->dirty_pages = ci->i_wrbuffer_ref_head;
+		ci->i_wrbuffer_ref_head = 0;
+		capsnap->context = snapc;
+		ci->i_head_snapc =
+			ceph_get_snap_context(ci->i_snap_realm->cached_context);
+		dout(" new snapc is %p\n", ci->i_head_snapc);
+		list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
+
+		if (used & CEPH_CAP_FILE_WR) {
+			dout("queue_cap_snap %p cap_snap %p snapc %p"
+			     " seq %llu used WR, now pending\n", inode,
+			     capsnap, snapc, snapc->seq);
+			capsnap->writing = 1;
+		} else {
+			/* note mtime, size NOW. */
+			__ceph_finish_cap_snap(ci, capsnap);
+		}
+	} else {
+		dout("queue_cap_snap %p nothing dirty|writing\n", inode);
+		kfree(capsnap);
+	}
+
+	spin_unlock(&ci->i_ceph_lock);
+}
+
+/*
+ * Finalize the size, mtime for a cap_snap.. that is, settle on final values
+ * to be used for the snapshot, to be flushed back to the mds.
+ *
+ * If capsnap can now be flushed, add to snap_flush list, and return 1.
+ *
+ * Caller must hold i_ceph_lock.
+ */
+int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
+			    struct ceph_cap_snap *capsnap)
+{
+	struct inode *inode = &ci->vfs_inode;
+	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+
+	BUG_ON(capsnap->writing);
+	capsnap->size = inode->i_size;
+	capsnap->mtime = inode->i_mtime;
+	capsnap->atime = inode->i_atime;
+	capsnap->ctime = inode->i_ctime;
+	capsnap->time_warp_seq = ci->i_time_warp_seq;
+	if (capsnap->dirty_pages) {
+		dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
+		     "still has %d dirty pages\n", inode, capsnap,
+		     capsnap->context, capsnap->context->seq,
+		     ceph_cap_string(capsnap->dirty), capsnap->size,
+		     capsnap->dirty_pages);
+		return 0;
+	}
+	dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
+	     inode, capsnap, capsnap->context,
+	     capsnap->context->seq, ceph_cap_string(capsnap->dirty),
+	     capsnap->size);
+
+	spin_lock(&mdsc->snap_flush_lock);
+	list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);
+	spin_unlock(&mdsc->snap_flush_lock);
+	return 1;  /* caller may want to ceph_flush_snaps */
+}
+
+/*
+ * Queue cap_snaps for snap writeback for this realm and its children.
+ * Called under snap_rwsem, so realm topology won't change.
+ */
+static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
+{
+	struct ceph_inode_info *ci;
+	struct inode *lastinode = NULL;
+	struct ceph_snap_realm *child;
+
+	dout("queue_realm_cap_snaps %p %llx inodes\n", realm, realm->ino);
+
+	spin_lock(&realm->inodes_with_caps_lock);
+	list_for_each_entry(ci, &realm->inodes_with_caps,
+			    i_snap_realm_item) {
+		struct inode *inode = igrab(&ci->vfs_inode);
+		if (!inode)
+			continue;
+		spin_unlock(&realm->inodes_with_caps_lock);
+		iput(lastinode);
+		lastinode = inode;
+		ceph_queue_cap_snap(ci);
+		spin_lock(&realm->inodes_with_caps_lock);
+	}
+	spin_unlock(&realm->inodes_with_caps_lock);
+	iput(lastinode);
+
+	list_for_each_entry(child, &realm->children, child_item) {
+		dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n",
+		     realm, realm->ino, child, child->ino);
+		list_del_init(&child->dirty_item);
+		list_add(&child->dirty_item, &realm->dirty_item);
+	}
+
+	list_del_init(&realm->dirty_item);
+	dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
+}
+
+/*
+ * Parse and apply a snapblob "snap trace" from the MDS.  This specifies
+ * the snap realm parameters from a given realm and all of its ancestors,
+ * up to the root.
+ *
+ * Caller must hold snap_rwsem for write.
+ */
+int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
+			   void *p, void *e, bool deletion,
+			   struct ceph_snap_realm **realm_ret)
+{
+	struct ceph_mds_snap_realm *ri;    /* encoded */
+	__le64 *snaps;                     /* encoded */
+	__le64 *prior_parent_snaps;        /* encoded */
+	struct ceph_snap_realm *realm = NULL;
+	struct ceph_snap_realm *first_realm = NULL;
+	int invalidate = 0;
+	int err = -ENOMEM;
+	LIST_HEAD(dirty_realms);
+
+	dout("update_snap_trace deletion=%d\n", deletion);
+more:
+	ceph_decode_need(&p, e, sizeof(*ri), bad);
+	ri = p;
+	p += sizeof(*ri);
+	ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) +
+			    le32_to_cpu(ri->num_prior_parent_snaps)), bad);
+	snaps = p;
+	p += sizeof(u64) * le32_to_cpu(ri->num_snaps);
+	prior_parent_snaps = p;
+	p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps);
+
+	realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino));
+	if (!realm) {
+		realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino));
+		if (IS_ERR(realm)) {
+			err = PTR_ERR(realm);
+			goto fail;
+		}
+	}
+
+	/* ensure the parent is correct */
+	err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent));
+	if (err < 0)
+		goto fail;
+	invalidate += err;
+
+	if (le64_to_cpu(ri->seq) > realm->seq) {
+		dout("update_snap_trace updating %llx %p %lld -> %lld\n",
+		     realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));
+		/* update realm parameters, snap lists */
+		realm->seq = le64_to_cpu(ri->seq);
+		realm->created = le64_to_cpu(ri->created);
+		realm->parent_since = le64_to_cpu(ri->parent_since);
+
+		realm->num_snaps = le32_to_cpu(ri->num_snaps);
+		err = dup_array(&realm->snaps, snaps, realm->num_snaps);
+		if (err < 0)
+			goto fail;
+
+		realm->num_prior_parent_snaps =
+			le32_to_cpu(ri->num_prior_parent_snaps);
+		err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps,
+				realm->num_prior_parent_snaps);
+		if (err < 0)
+			goto fail;
+
+		/* queue realm for cap_snap creation */
+		list_add(&realm->dirty_item, &dirty_realms);
+
+		invalidate = 1;
+	} else if (!realm->cached_context) {
+		dout("update_snap_trace %llx %p seq %lld new\n",
+		     realm->ino, realm, realm->seq);
+		invalidate = 1;
+	} else {
+		dout("update_snap_trace %llx %p seq %lld unchanged\n",
+		     realm->ino, realm, realm->seq);
+	}
+
+	dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino,
+	     realm, invalidate, p, e);
+
+	/* invalidate when we reach the _end_ (root) of the trace */
+	if (invalidate && p >= e)
+		rebuild_snap_realms(realm);
+
+	if (!first_realm)
+		first_realm = realm;
+	else
+		ceph_put_snap_realm(mdsc, realm);
+
+	if (p < e)
+		goto more;
+
+	/*
+	 * queue cap snaps _after_ we've built the new snap contexts,
+	 * so that i_head_snapc can be set appropriately.
+	 */
+	while (!list_empty(&dirty_realms)) {
+		realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,
+					 dirty_item);
+		queue_realm_cap_snaps(realm);
+	}
+
+	if (realm_ret)
+		*realm_ret = first_realm;
+	else
+		ceph_put_snap_realm(mdsc, first_realm);
+
+	__cleanup_empty_realms(mdsc);
+	return 0;
+
+bad:
+	err = -EINVAL;
+fail:
+	if (realm && !IS_ERR(realm))
+		ceph_put_snap_realm(mdsc, realm);
+	if (first_realm)
+		ceph_put_snap_realm(mdsc, first_realm);
+	pr_err("update_snap_trace error %d\n", err);
+	return err;
+}
+
+
+/*
+ * Send any cap_snaps that are queued for flush.  Try to carry
+ * s_mutex across multiple snap flushes to avoid locking overhead.
+ *
+ * Caller holds no locks.
+ */
+static void flush_snaps(struct ceph_mds_client *mdsc)
+{
+	struct ceph_inode_info *ci;
+	struct inode *inode;
+	struct ceph_mds_session *session = NULL;
+
+	dout("flush_snaps\n");
+	spin_lock(&mdsc->snap_flush_lock);
+	while (!list_empty(&mdsc->snap_flush_list)) {
+		ci = list_first_entry(&mdsc->snap_flush_list,
+				struct ceph_inode_info, i_snap_flush_item);
+		inode = &ci->vfs_inode;
+		ihold(inode);
+		spin_unlock(&mdsc->snap_flush_lock);
+		spin_lock(&ci->i_ceph_lock);
+		__ceph_flush_snaps(ci, &session, 0);
+		spin_unlock(&ci->i_ceph_lock);
+		iput(inode);
+		spin_lock(&mdsc->snap_flush_lock);
+	}
+	spin_unlock(&mdsc->snap_flush_lock);
+
+	if (session) {
+		mutex_unlock(&session->s_mutex);
+		ceph_put_mds_session(session);
+	}
+	dout("flush_snaps done\n");
+}
+
+
+/*
+ * Handle a snap notification from the MDS.
+ *
+ * This can take two basic forms: the simplest is just a snap creation
+ * or deletion notification on an existing realm.  This should update the
+ * realm and its children.
+ *
+ * The more difficult case is realm creation, due to snap creation at a
+ * new point in the file hierarchy, or due to a rename that moves a file or
+ * directory into another realm.
+ */
+void ceph_handle_snap(struct ceph_mds_client *mdsc,
+		      struct ceph_mds_session *session,
+		      struct ceph_msg *msg)
+{
+	struct super_block *sb = mdsc->fsc->sb;
+	int mds = session->s_mds;
+	u64 split;
+	int op;
+	int trace_len;
+	struct ceph_snap_realm *realm = NULL;
+	void *p = msg->front.iov_base;
+	void *e = p + msg->front.iov_len;
+	struct ceph_mds_snap_head *h;
+	int num_split_inos, num_split_realms;
+	__le64 *split_inos = NULL, *split_realms = NULL;
+	int i;
+	int locked_rwsem = 0;
+
+	/* decode */
+	if (msg->front.iov_len < sizeof(*h))
+		goto bad;
+	h = p;
+	op = le32_to_cpu(h->op);
+	split = le64_to_cpu(h->split);   /* non-zero if we are splitting an
+					  * existing realm */
+	num_split_inos = le32_to_cpu(h->num_split_inos);
+	num_split_realms = le32_to_cpu(h->num_split_realms);
+	trace_len = le32_to_cpu(h->trace_len);
+	p += sizeof(*h);
+
+	dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds,
+	     ceph_snap_op_name(op), split, trace_len);
+
+	mutex_lock(&session->s_mutex);
+	session->s_seq++;
+	mutex_unlock(&session->s_mutex);
+
+	down_write(&mdsc->snap_rwsem);
+	locked_rwsem = 1;
+
+	if (op == CEPH_SNAP_OP_SPLIT) {
+		struct ceph_mds_snap_realm *ri;
+
+		/*
+		 * A "split" breaks part of an existing realm off into
+		 * a new realm.  The MDS provides a list of inodes
+		 * (with caps) and child realms that belong to the new
+		 * child.
+		 */
+		split_inos = p;
+		p += sizeof(u64) * num_split_inos;
+		split_realms = p;
+		p += sizeof(u64) * num_split_realms;
+		ceph_decode_need(&p, e, sizeof(*ri), bad);
+		/* we will peek at realm info here, but will _not_
+		 * advance p, as the realm update will occur below in
+		 * ceph_update_snap_trace. */
+		ri = p;
+
+		realm = ceph_lookup_snap_realm(mdsc, split);
+		if (!realm) {
+			realm = ceph_create_snap_realm(mdsc, split);
+			if (IS_ERR(realm))
+				goto out;
+		}
+
+		dout("splitting snap_realm %llx %p\n", realm->ino, realm);
+		for (i = 0; i < num_split_inos; i++) {
+			struct ceph_vino vino = {
+				.ino = le64_to_cpu(split_inos[i]),
+				.snap = CEPH_NOSNAP,
+			};
+			struct inode *inode = ceph_find_inode(sb, vino);
+			struct ceph_inode_info *ci;
+			struct ceph_snap_realm *oldrealm;
+
+			if (!inode)
+				continue;
+			ci = ceph_inode(inode);
+
+			spin_lock(&ci->i_ceph_lock);
+			if (!ci->i_snap_realm)
+				goto skip_inode;
+			/*
+			 * If this inode belongs to a realm that was
+			 * created after our new realm, we experienced
+			 * a race (due to another split notifications
+			 * arriving from a different MDS).  So skip
+			 * this inode.
+			 */
+			if (ci->i_snap_realm->created >
+			    le64_to_cpu(ri->created)) {
+				dout(" leaving %p in newer realm %llx %p\n",
+				     inode, ci->i_snap_realm->ino,
+				     ci->i_snap_realm);
+				goto skip_inode;
+			}
+			dout(" will move %p to split realm %llx %p\n",
+			     inode, realm->ino, realm);
+			/*
+			 * Move the inode to the new realm
+			 */
+			spin_lock(&realm->inodes_with_caps_lock);
+			list_del_init(&ci->i_snap_realm_item);
+			list_add(&ci->i_snap_realm_item,
+				 &realm->inodes_with_caps);
+			oldrealm = ci->i_snap_realm;
+			ci->i_snap_realm = realm;
+			spin_unlock(&realm->inodes_with_caps_lock);
+			spin_unlock(&ci->i_ceph_lock);
+
+			ceph_get_snap_realm(mdsc, realm);
+			ceph_put_snap_realm(mdsc, oldrealm);
+
+			iput(inode);
+			continue;
+
+skip_inode:
+			spin_unlock(&ci->i_ceph_lock);
+			iput(inode);
+		}
+
+		/* we may have taken some of the old realm's children. */
+		for (i = 0; i < num_split_realms; i++) {
+			struct ceph_snap_realm *child =
+				__lookup_snap_realm(mdsc,
+					   le64_to_cpu(split_realms[i]));
+			if (!child)
+				continue;
+			adjust_snap_realm_parent(mdsc, child, realm->ino);
+		}
+	}
+
+	/*
+	 * update using the provided snap trace. if we are deleting a
+	 * snap, we can avoid queueing cap_snaps.
+	 */
+	ceph_update_snap_trace(mdsc, p, e,
+			       op == CEPH_SNAP_OP_DESTROY, NULL);
+
+	if (op == CEPH_SNAP_OP_SPLIT)
+		/* we took a reference when we created the realm, above */
+		ceph_put_snap_realm(mdsc, realm);
+
+	__cleanup_empty_realms(mdsc);
+
+	up_write(&mdsc->snap_rwsem);
+
+	flush_snaps(mdsc);
+	return;
+
+bad:
+	pr_err("corrupt snap message from mds%d\n", mds);
+	ceph_msg_dump(msg);
+out:
+	if (locked_rwsem)
+		up_write(&mdsc->snap_rwsem);
+	return;
+}
+
+int __init ceph_snap_init(void)
+{
+	empty_snapc = ceph_create_snap_context(0, GFP_NOFS);
+	if (!empty_snapc)
+		return -ENOMEM;
+	empty_snapc->seq = 1;
+	return 0;
+}
+
+void ceph_snap_exit(void)
+{
+	ceph_put_snap_context(empty_snapc);
+}
diff --git a/fs/ceph/strings.c b/fs/ceph/strings.c
new file mode 100644
index 000000000..89e6bc321
--- /dev/null
+++ b/fs/ceph/strings.c
@@ -0,0 +1,125 @@
+/*
+ * Ceph fs string constants
+ */
+#include <linux/module.h>
+#include <linux/ceph/types.h>
+
+
+const char *ceph_mds_state_name(int s)
+{
+	switch (s) {
+		/* down and out */
+	case CEPH_MDS_STATE_DNE:        return "down:dne";
+	case CEPH_MDS_STATE_STOPPED:    return "down:stopped";
+		/* up and out */
+	case CEPH_MDS_STATE_BOOT:       return "up:boot";
+	case CEPH_MDS_STATE_STANDBY:    return "up:standby";
+	case CEPH_MDS_STATE_STANDBY_REPLAY:    return "up:standby-replay";
+	case CEPH_MDS_STATE_REPLAYONCE: return "up:oneshot-replay";
+	case CEPH_MDS_STATE_CREATING:   return "up:creating";
+	case CEPH_MDS_STATE_STARTING:   return "up:starting";
+		/* up and in */
+	case CEPH_MDS_STATE_REPLAY:     return "up:replay";
+	case CEPH_MDS_STATE_RESOLVE:    return "up:resolve";
+	case CEPH_MDS_STATE_RECONNECT:  return "up:reconnect";
+	case CEPH_MDS_STATE_REJOIN:     return "up:rejoin";
+	case CEPH_MDS_STATE_CLIENTREPLAY: return "up:clientreplay";
+	case CEPH_MDS_STATE_ACTIVE:     return "up:active";
+	case CEPH_MDS_STATE_STOPPING:   return "up:stopping";
+	}
+	return "???";
+}
+
+const char *ceph_session_op_name(int op)
+{
+	switch (op) {
+	case CEPH_SESSION_REQUEST_OPEN: return "request_open";
+	case CEPH_SESSION_OPEN: return "open";
+	case CEPH_SESSION_REQUEST_CLOSE: return "request_close";
+	case CEPH_SESSION_CLOSE: return "close";
+	case CEPH_SESSION_REQUEST_RENEWCAPS: return "request_renewcaps";
+	case CEPH_SESSION_RENEWCAPS: return "renewcaps";
+	case CEPH_SESSION_STALE: return "stale";
+	case CEPH_SESSION_RECALL_STATE: return "recall_state";
+	case CEPH_SESSION_FLUSHMSG: return "flushmsg";
+	case CEPH_SESSION_FLUSHMSG_ACK: return "flushmsg_ack";
+	}
+	return "???";
+}
+
+const char *ceph_mds_op_name(int op)
+{
+	switch (op) {
+	case CEPH_MDS_OP_LOOKUP:  return "lookup";
+	case CEPH_MDS_OP_LOOKUPHASH:  return "lookuphash";
+	case CEPH_MDS_OP_LOOKUPPARENT:  return "lookupparent";
+	case CEPH_MDS_OP_LOOKUPINO:  return "lookupino";
+	case CEPH_MDS_OP_LOOKUPNAME:  return "lookupname";
+	case CEPH_MDS_OP_GETATTR:  return "getattr";
+	case CEPH_MDS_OP_SETXATTR: return "setxattr";
+	case CEPH_MDS_OP_SETATTR: return "setattr";
+	case CEPH_MDS_OP_RMXATTR: return "rmxattr";
+	case CEPH_MDS_OP_SETLAYOUT: return "setlayou";
+	case CEPH_MDS_OP_SETDIRLAYOUT: return "setdirlayout";
+	case CEPH_MDS_OP_READDIR: return "readdir";
+	case CEPH_MDS_OP_MKNOD: return "mknod";
+	case CEPH_MDS_OP_LINK: return "link";
+	case CEPH_MDS_OP_UNLINK: return "unlink";
+	case CEPH_MDS_OP_RENAME: return "rename";
+	case CEPH_MDS_OP_MKDIR: return "mkdir";
+	case CEPH_MDS_OP_RMDIR: return "rmdir";
+	case CEPH_MDS_OP_SYMLINK: return "symlink";
+	case CEPH_MDS_OP_CREATE: return "create";
+	case CEPH_MDS_OP_OPEN: return "open";
+	case CEPH_MDS_OP_LOOKUPSNAP: return "lookupsnap";
+	case CEPH_MDS_OP_LSSNAP: return "lssnap";
+	case CEPH_MDS_OP_MKSNAP: return "mksnap";
+	case CEPH_MDS_OP_RMSNAP: return "rmsnap";
+	case CEPH_MDS_OP_RENAMESNAP: return "renamesnap";
+	case CEPH_MDS_OP_SETFILELOCK: return "setfilelock";
+	case CEPH_MDS_OP_GETFILELOCK: return "getfilelock";
+	}
+	return "???";
+}
+
+const char *ceph_cap_op_name(int op)
+{
+	switch (op) {
+	case CEPH_CAP_OP_GRANT: return "grant";
+	case CEPH_CAP_OP_REVOKE: return "revoke";
+	case CEPH_CAP_OP_TRUNC: return "trunc";
+	case CEPH_CAP_OP_EXPORT: return "export";
+	case CEPH_CAP_OP_IMPORT: return "import";
+	case CEPH_CAP_OP_UPDATE: return "update";
+	case CEPH_CAP_OP_DROP: return "drop";
+	case CEPH_CAP_OP_FLUSH: return "flush";
+	case CEPH_CAP_OP_FLUSH_ACK: return "flush_ack";
+	case CEPH_CAP_OP_FLUSHSNAP: return "flushsnap";
+	case CEPH_CAP_OP_FLUSHSNAP_ACK: return "flushsnap_ack";
+	case CEPH_CAP_OP_RELEASE: return "release";
+	case CEPH_CAP_OP_RENEW: return "renew";
+	}
+	return "???";
+}
+
+const char *ceph_lease_op_name(int o)
+{
+	switch (o) {
+	case CEPH_MDS_LEASE_REVOKE: return "revoke";
+	case CEPH_MDS_LEASE_RELEASE: return "release";
+	case CEPH_MDS_LEASE_RENEW: return "renew";
+	case CEPH_MDS_LEASE_REVOKE_ACK: return "revoke_ack";
+	}
+	return "???";
+}
+
+const char *ceph_snap_op_name(int o)
+{
+	switch (o) {
+	case CEPH_SNAP_OP_UPDATE: return "update";
+	case CEPH_SNAP_OP_CREATE: return "create";
+	case CEPH_SNAP_OP_DESTROY: return "destroy";
+	case CEPH_SNAP_OP_SPLIT: return "split";
+	}
+	return "???";
+}
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
new file mode 100644
index 000000000..4e9905374
--- /dev/null
+++ b/fs/ceph/super.c
@@ -0,0 +1,1059 @@
+
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/backing-dev.h>
+#include <linux/ctype.h>
+#include <linux/fs.h>
+#include <linux/inet.h>
+#include <linux/in6.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/parser.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/statfs.h>
+#include <linux/string.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include "cache.h"
+
+#include <linux/ceph/ceph_features.h>
+#include <linux/ceph/decode.h>
+#include <linux/ceph/mon_client.h>
+#include <linux/ceph/auth.h>
+#include <linux/ceph/debugfs.h>
+
+/*
+ * Ceph superblock operations
+ *
+ * Handle the basics of mounting, unmounting.
+ */
+
+/*
+ * super ops
+ */
+static void ceph_put_super(struct super_block *s)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(s);
+
+	dout("put_super\n");
+	ceph_mdsc_close_sessions(fsc->mdsc);
+}
+
+static int ceph_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct ceph_fs_client *fsc = ceph_inode_to_client(d_inode(dentry));
+	struct ceph_monmap *monmap = fsc->client->monc.monmap;
+	struct ceph_statfs st;
+	u64 fsid;
+	int err;
+
+	dout("statfs\n");
+	err = ceph_monc_do_statfs(&fsc->client->monc, &st);
+	if (err < 0)
+		return err;
+
+	/* fill in kstatfs */
+	buf->f_type = CEPH_SUPER_MAGIC;  /* ?? */
+
+	/*
+	 * express utilization in terms of large blocks to avoid
+	 * overflow on 32-bit machines.
+	 *
+	 * NOTE: for the time being, we make bsize == frsize to humor
+	 * not-yet-ancient versions of glibc that are broken.
+	 * Someday, we will probably want to report a real block
+	 * size...  whatever that may mean for a network file system!
+	 */
+	buf->f_bsize = 1 << CEPH_BLOCK_SHIFT;
+	buf->f_frsize = 1 << CEPH_BLOCK_SHIFT;
+	buf->f_blocks = le64_to_cpu(st.kb) >> (CEPH_BLOCK_SHIFT-10);
+	buf->f_bfree = le64_to_cpu(st.kb_avail) >> (CEPH_BLOCK_SHIFT-10);
+	buf->f_bavail = le64_to_cpu(st.kb_avail) >> (CEPH_BLOCK_SHIFT-10);
+
+	buf->f_files = le64_to_cpu(st.num_objects);
+	buf->f_ffree = -1;
+	buf->f_namelen = NAME_MAX;
+
+	/* leave fsid little-endian, regardless of host endianness */
+	fsid = *(u64 *)(&monmap->fsid) ^ *((u64 *)&monmap->fsid + 1);
+	buf->f_fsid.val[0] = fsid & 0xffffffff;
+	buf->f_fsid.val[1] = fsid >> 32;
+
+	return 0;
+}
+
+
+static int ceph_sync_fs(struct super_block *sb, int wait)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+
+	if (!wait) {
+		dout("sync_fs (non-blocking)\n");
+		ceph_flush_dirty_caps(fsc->mdsc);
+		dout("sync_fs (non-blocking) done\n");
+		return 0;
+	}
+
+	dout("sync_fs (blocking)\n");
+	ceph_osdc_sync(&fsc->client->osdc);
+	ceph_mdsc_sync(fsc->mdsc);
+	dout("sync_fs (blocking) done\n");
+	return 0;
+}
+
+/*
+ * mount options
+ */
+enum {
+	Opt_wsize,
+	Opt_rsize,
+	Opt_rasize,
+	Opt_caps_wanted_delay_min,
+	Opt_caps_wanted_delay_max,
+	Opt_cap_release_safety,
+	Opt_readdir_max_entries,
+	Opt_readdir_max_bytes,
+	Opt_congestion_kb,
+	Opt_last_int,
+	/* int args above */
+	Opt_snapdirname,
+	Opt_last_string,
+	/* string args above */
+	Opt_dirstat,
+	Opt_nodirstat,
+	Opt_rbytes,
+	Opt_norbytes,
+	Opt_asyncreaddir,
+	Opt_noasyncreaddir,
+	Opt_dcache,
+	Opt_nodcache,
+	Opt_ino32,
+	Opt_noino32,
+	Opt_fscache,
+	Opt_nofscache,
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+	Opt_acl,
+#endif
+	Opt_noacl
+};
+
+static match_table_t fsopt_tokens = {
+	{Opt_wsize, "wsize=%d"},
+	{Opt_rsize, "rsize=%d"},
+	{Opt_rasize, "rasize=%d"},
+	{Opt_caps_wanted_delay_min, "caps_wanted_delay_min=%d"},
+	{Opt_caps_wanted_delay_max, "caps_wanted_delay_max=%d"},
+	{Opt_cap_release_safety, "cap_release_safety=%d"},
+	{Opt_readdir_max_entries, "readdir_max_entries=%d"},
+	{Opt_readdir_max_bytes, "readdir_max_bytes=%d"},
+	{Opt_congestion_kb, "write_congestion_kb=%d"},
+	/* int args above */
+	{Opt_snapdirname, "snapdirname=%s"},
+	/* string args above */
+	{Opt_dirstat, "dirstat"},
+	{Opt_nodirstat, "nodirstat"},
+	{Opt_rbytes, "rbytes"},
+	{Opt_norbytes, "norbytes"},
+	{Opt_asyncreaddir, "asyncreaddir"},
+	{Opt_noasyncreaddir, "noasyncreaddir"},
+	{Opt_dcache, "dcache"},
+	{Opt_nodcache, "nodcache"},
+	{Opt_ino32, "ino32"},
+	{Opt_noino32, "noino32"},
+	{Opt_fscache, "fsc"},
+	{Opt_nofscache, "nofsc"},
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+	{Opt_acl, "acl"},
+#endif
+	{Opt_noacl, "noacl"},
+	{-1, NULL}
+};
+
+static int parse_fsopt_token(char *c, void *private)
+{
+	struct ceph_mount_options *fsopt = private;
+	substring_t argstr[MAX_OPT_ARGS];
+	int token, intval, ret;
+
+	token = match_token((char *)c, fsopt_tokens, argstr);
+	if (token < 0)
+		return -EINVAL;
+
+	if (token < Opt_last_int) {
+		ret = match_int(&argstr[0], &intval);
+		if (ret < 0) {
+			pr_err("bad mount option arg (not int) "
+			       "at '%s'\n", c);
+			return ret;
+		}
+		dout("got int token %d val %d\n", token, intval);
+	} else if (token > Opt_last_int && token < Opt_last_string) {
+		dout("got string token %d val %s\n", token,
+		     argstr[0].from);
+	} else {
+		dout("got token %d\n", token);
+	}
+
+	switch (token) {
+	case Opt_snapdirname:
+		kfree(fsopt->snapdir_name);
+		fsopt->snapdir_name = kstrndup(argstr[0].from,
+					       argstr[0].to-argstr[0].from,
+					       GFP_KERNEL);
+		if (!fsopt->snapdir_name)
+			return -ENOMEM;
+		break;
+
+		/* misc */
+	case Opt_wsize:
+		fsopt->wsize = intval;
+		break;
+	case Opt_rsize:
+		fsopt->rsize = intval;
+		break;
+	case Opt_rasize:
+		fsopt->rasize = intval;
+		break;
+	case Opt_caps_wanted_delay_min:
+		fsopt->caps_wanted_delay_min = intval;
+		break;
+	case Opt_caps_wanted_delay_max:
+		fsopt->caps_wanted_delay_max = intval;
+		break;
+	case Opt_readdir_max_entries:
+		fsopt->max_readdir = intval;
+		break;
+	case Opt_readdir_max_bytes:
+		fsopt->max_readdir_bytes = intval;
+		break;
+	case Opt_congestion_kb:
+		fsopt->congestion_kb = intval;
+		break;
+	case Opt_dirstat:
+		fsopt->flags |= CEPH_MOUNT_OPT_DIRSTAT;
+		break;
+	case Opt_nodirstat:
+		fsopt->flags &= ~CEPH_MOUNT_OPT_DIRSTAT;
+		break;
+	case Opt_rbytes:
+		fsopt->flags |= CEPH_MOUNT_OPT_RBYTES;
+		break;
+	case Opt_norbytes:
+		fsopt->flags &= ~CEPH_MOUNT_OPT_RBYTES;
+		break;
+	case Opt_asyncreaddir:
+		fsopt->flags &= ~CEPH_MOUNT_OPT_NOASYNCREADDIR;
+		break;
+	case Opt_noasyncreaddir:
+		fsopt->flags |= CEPH_MOUNT_OPT_NOASYNCREADDIR;
+		break;
+	case Opt_dcache:
+		fsopt->flags |= CEPH_MOUNT_OPT_DCACHE;
+		break;
+	case Opt_nodcache:
+		fsopt->flags &= ~CEPH_MOUNT_OPT_DCACHE;
+		break;
+	case Opt_ino32:
+		fsopt->flags |= CEPH_MOUNT_OPT_INO32;
+		break;
+	case Opt_noino32:
+		fsopt->flags &= ~CEPH_MOUNT_OPT_INO32;
+		break;
+	case Opt_fscache:
+		fsopt->flags |= CEPH_MOUNT_OPT_FSCACHE;
+		break;
+	case Opt_nofscache:
+		fsopt->flags &= ~CEPH_MOUNT_OPT_FSCACHE;
+		break;
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+	case Opt_acl:
+		fsopt->sb_flags |= MS_POSIXACL;
+		break;
+#endif
+	case Opt_noacl:
+		fsopt->sb_flags &= ~MS_POSIXACL;
+		break;
+	default:
+		BUG_ON(token);
+	}
+	return 0;
+}
+
+static void destroy_mount_options(struct ceph_mount_options *args)
+{
+	dout("destroy_mount_options %p\n", args);
+	kfree(args->snapdir_name);
+	kfree(args);
+}
+
+static int strcmp_null(const char *s1, const char *s2)
+{
+	if (!s1 && !s2)
+		return 0;
+	if (s1 && !s2)
+		return -1;
+	if (!s1 && s2)
+		return 1;
+	return strcmp(s1, s2);
+}
+
+static int compare_mount_options(struct ceph_mount_options *new_fsopt,
+				 struct ceph_options *new_opt,
+				 struct ceph_fs_client *fsc)
+{
+	struct ceph_mount_options *fsopt1 = new_fsopt;
+	struct ceph_mount_options *fsopt2 = fsc->mount_options;
+	int ofs = offsetof(struct ceph_mount_options, snapdir_name);
+	int ret;
+
+	ret = memcmp(fsopt1, fsopt2, ofs);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(fsopt1->snapdir_name, fsopt2->snapdir_name);
+	if (ret)
+		return ret;
+
+	return ceph_compare_options(new_opt, fsc->client);
+}
+
+static int parse_mount_options(struct ceph_mount_options **pfsopt,
+			       struct ceph_options **popt,
+			       int flags, char *options,
+			       const char *dev_name,
+			       const char **path)
+{
+	struct ceph_mount_options *fsopt;
+	const char *dev_name_end;
+	int err;
+
+	if (!dev_name || !*dev_name)
+		return -EINVAL;
+
+	fsopt = kzalloc(sizeof(*fsopt), GFP_KERNEL);
+	if (!fsopt)
+		return -ENOMEM;
+
+	dout("parse_mount_options %p, dev_name '%s'\n", fsopt, dev_name);
+
+	fsopt->sb_flags = flags;
+	fsopt->flags = CEPH_MOUNT_OPT_DEFAULT;
+
+	fsopt->rsize = CEPH_RSIZE_DEFAULT;
+	fsopt->rasize = CEPH_RASIZE_DEFAULT;
+	fsopt->snapdir_name = kstrdup(CEPH_SNAPDIRNAME_DEFAULT, GFP_KERNEL);
+	if (!fsopt->snapdir_name) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	fsopt->caps_wanted_delay_min = CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT;
+	fsopt->caps_wanted_delay_max = CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT;
+	fsopt->cap_release_safety = CEPH_CAP_RELEASE_SAFETY_DEFAULT;
+	fsopt->max_readdir = CEPH_MAX_READDIR_DEFAULT;
+	fsopt->max_readdir_bytes = CEPH_MAX_READDIR_BYTES_DEFAULT;
+	fsopt->congestion_kb = default_congestion_kb();
+
+	/*
+	 * Distinguish the server list from the path in "dev_name".
+	 * Internally we do not include the leading '/' in the path.
+	 *
+	 * "dev_name" will look like:
+	 *     <server_spec>[,<server_spec>...]:[<path>]
+	 * where
+	 *     <server_spec> is <ip>[:<port>]
+	 *     <path> is optional, but if present must begin with '/'
+	 */
+	dev_name_end = strchr(dev_name, '/');
+	if (dev_name_end) {
+		/* skip over leading '/' for path */
+		*path = dev_name_end + 1;
+	} else {
+		/* path is empty */
+		dev_name_end = dev_name + strlen(dev_name);
+		*path = dev_name_end;
+	}
+	err = -EINVAL;
+	dev_name_end--;		/* back up to ':' separator */
+	if (dev_name_end < dev_name || *dev_name_end != ':') {
+		pr_err("device name is missing path (no : separator in %s)\n",
+				dev_name);
+		goto out;
+	}
+	dout("device name '%.*s'\n", (int)(dev_name_end - dev_name), dev_name);
+	dout("server path '%s'\n", *path);
+
+	*popt = ceph_parse_options(options, dev_name, dev_name_end,
+				 parse_fsopt_token, (void *)fsopt);
+	if (IS_ERR(*popt)) {
+		err = PTR_ERR(*popt);
+		goto out;
+	}
+
+	/* success */
+	*pfsopt = fsopt;
+	return 0;
+
+out:
+	destroy_mount_options(fsopt);
+	return err;
+}
+
+/**
+ * ceph_show_options - Show mount options in /proc/mounts
+ * @m: seq_file to write to
+ * @root: root of that (sub)tree
+ */
+static int ceph_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(root->d_sb);
+	struct ceph_mount_options *fsopt = fsc->mount_options;
+	size_t pos;
+	int ret;
+
+	/* a comma between MNT/MS and client options */
+	seq_putc(m, ',');
+	pos = m->count;
+
+	ret = ceph_print_client_options(m, fsc->client);
+	if (ret)
+		return ret;
+
+	/* retract our comma if no client options */
+	if (m->count == pos)
+		m->count--;
+
+	if (fsopt->flags & CEPH_MOUNT_OPT_DIRSTAT)
+		seq_puts(m, ",dirstat");
+	if ((fsopt->flags & CEPH_MOUNT_OPT_RBYTES) == 0)
+		seq_puts(m, ",norbytes");
+	if (fsopt->flags & CEPH_MOUNT_OPT_NOASYNCREADDIR)
+		seq_puts(m, ",noasyncreaddir");
+	if ((fsopt->flags & CEPH_MOUNT_OPT_DCACHE) == 0)
+		seq_puts(m, ",nodcache");
+	if (fsopt->flags & CEPH_MOUNT_OPT_FSCACHE)
+		seq_puts(m, ",fsc");
+
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+	if (fsopt->sb_flags & MS_POSIXACL)
+		seq_puts(m, ",acl");
+	else
+		seq_puts(m, ",noacl");
+#endif
+
+	if (fsopt->wsize)
+		seq_printf(m, ",wsize=%d", fsopt->wsize);
+	if (fsopt->rsize != CEPH_RSIZE_DEFAULT)
+		seq_printf(m, ",rsize=%d", fsopt->rsize);
+	if (fsopt->rasize != CEPH_RASIZE_DEFAULT)
+		seq_printf(m, ",rasize=%d", fsopt->rasize);
+	if (fsopt->congestion_kb != default_congestion_kb())
+		seq_printf(m, ",write_congestion_kb=%d", fsopt->congestion_kb);
+	if (fsopt->caps_wanted_delay_min != CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT)
+		seq_printf(m, ",caps_wanted_delay_min=%d",
+			 fsopt->caps_wanted_delay_min);
+	if (fsopt->caps_wanted_delay_max != CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT)
+		seq_printf(m, ",caps_wanted_delay_max=%d",
+			   fsopt->caps_wanted_delay_max);
+	if (fsopt->cap_release_safety != CEPH_CAP_RELEASE_SAFETY_DEFAULT)
+		seq_printf(m, ",cap_release_safety=%d",
+			   fsopt->cap_release_safety);
+	if (fsopt->max_readdir != CEPH_MAX_READDIR_DEFAULT)
+		seq_printf(m, ",readdir_max_entries=%d", fsopt->max_readdir);
+	if (fsopt->max_readdir_bytes != CEPH_MAX_READDIR_BYTES_DEFAULT)
+		seq_printf(m, ",readdir_max_bytes=%d", fsopt->max_readdir_bytes);
+	if (strcmp(fsopt->snapdir_name, CEPH_SNAPDIRNAME_DEFAULT))
+		seq_printf(m, ",snapdirname=%s", fsopt->snapdir_name);
+
+	return 0;
+}
+
+/*
+ * handle any mon messages the standard library doesn't understand.
+ * return error if we don't either.
+ */
+static int extra_mon_dispatch(struct ceph_client *client, struct ceph_msg *msg)
+{
+	struct ceph_fs_client *fsc = client->private;
+	int type = le16_to_cpu(msg->hdr.type);
+
+	switch (type) {
+	case CEPH_MSG_MDS_MAP:
+		ceph_mdsc_handle_map(fsc->mdsc, msg);
+		return 0;
+
+	default:
+		return -1;
+	}
+}
+
+/*
+ * create a new fs client
+ */
+static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
+					struct ceph_options *opt)
+{
+	struct ceph_fs_client *fsc;
+	const u64 supported_features =
+		CEPH_FEATURE_FLOCK |
+		CEPH_FEATURE_DIRLAYOUTHASH |
+		CEPH_FEATURE_MDS_INLINE_DATA;
+	const u64 required_features = 0;
+	int page_count;
+	size_t size;
+	int err = -ENOMEM;
+
+	fsc = kzalloc(sizeof(*fsc), GFP_KERNEL);
+	if (!fsc)
+		return ERR_PTR(-ENOMEM);
+
+	fsc->client = ceph_create_client(opt, fsc, supported_features,
+					 required_features);
+	if (IS_ERR(fsc->client)) {
+		err = PTR_ERR(fsc->client);
+		goto fail;
+	}
+	fsc->client->extra_mon_dispatch = extra_mon_dispatch;
+	fsc->client->monc.want_mdsmap = 1;
+
+	fsc->mount_options = fsopt;
+
+	fsc->sb = NULL;
+	fsc->mount_state = CEPH_MOUNT_MOUNTING;
+
+	atomic_long_set(&fsc->writeback_count, 0);
+
+	err = bdi_init(&fsc->backing_dev_info);
+	if (err < 0)
+		goto fail_client;
+
+	err = -ENOMEM;
+	/*
+	 * The number of concurrent works can be high but they don't need
+	 * to be processed in parallel, limit concurrency.
+	 */
+	fsc->wb_wq = alloc_workqueue("ceph-writeback", 0, 1);
+	if (fsc->wb_wq == NULL)
+		goto fail_bdi;
+	fsc->pg_inv_wq = alloc_workqueue("ceph-pg-invalid", 0, 1);
+	if (fsc->pg_inv_wq == NULL)
+		goto fail_wb_wq;
+	fsc->trunc_wq = alloc_workqueue("ceph-trunc", 0, 1);
+	if (fsc->trunc_wq == NULL)
+		goto fail_pg_inv_wq;
+
+	/* set up mempools */
+	err = -ENOMEM;
+	page_count = fsc->mount_options->wsize >> PAGE_CACHE_SHIFT;
+	size = sizeof (struct page *) * (page_count ? page_count : 1);
+	fsc->wb_pagevec_pool = mempool_create_kmalloc_pool(10, size);
+	if (!fsc->wb_pagevec_pool)
+		goto fail_trunc_wq;
+
+	/* setup fscache */
+	if ((fsopt->flags & CEPH_MOUNT_OPT_FSCACHE) &&
+	    (ceph_fscache_register_fs(fsc) != 0))
+		goto fail_fscache;
+
+	/* caps */
+	fsc->min_caps = fsopt->max_readdir;
+
+	return fsc;
+
+fail_fscache:
+	ceph_fscache_unregister_fs(fsc);
+fail_trunc_wq:
+	destroy_workqueue(fsc->trunc_wq);
+fail_pg_inv_wq:
+	destroy_workqueue(fsc->pg_inv_wq);
+fail_wb_wq:
+	destroy_workqueue(fsc->wb_wq);
+fail_bdi:
+	bdi_destroy(&fsc->backing_dev_info);
+fail_client:
+	ceph_destroy_client(fsc->client);
+fail:
+	kfree(fsc);
+	return ERR_PTR(err);
+}
+
+static void destroy_fs_client(struct ceph_fs_client *fsc)
+{
+	dout("destroy_fs_client %p\n", fsc);
+
+	ceph_fscache_unregister_fs(fsc);
+
+	destroy_workqueue(fsc->wb_wq);
+	destroy_workqueue(fsc->pg_inv_wq);
+	destroy_workqueue(fsc->trunc_wq);
+
+	bdi_destroy(&fsc->backing_dev_info);
+
+	mempool_destroy(fsc->wb_pagevec_pool);
+
+	destroy_mount_options(fsc->mount_options);
+
+	ceph_fs_debugfs_cleanup(fsc);
+
+	ceph_destroy_client(fsc->client);
+
+	kfree(fsc);
+	dout("destroy_fs_client %p done\n", fsc);
+}
+
+/*
+ * caches
+ */
+struct kmem_cache *ceph_inode_cachep;
+struct kmem_cache *ceph_cap_cachep;
+struct kmem_cache *ceph_dentry_cachep;
+struct kmem_cache *ceph_file_cachep;
+
+static void ceph_inode_init_once(void *foo)
+{
+	struct ceph_inode_info *ci = foo;
+	inode_init_once(&ci->vfs_inode);
+}
+
+static int __init init_caches(void)
+{
+	int error = -ENOMEM;
+
+	ceph_inode_cachep = kmem_cache_create("ceph_inode_info",
+				      sizeof(struct ceph_inode_info),
+				      __alignof__(struct ceph_inode_info),
+				      (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD),
+				      ceph_inode_init_once);
+	if (ceph_inode_cachep == NULL)
+		return -ENOMEM;
+
+	ceph_cap_cachep = KMEM_CACHE(ceph_cap,
+				     SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (ceph_cap_cachep == NULL)
+		goto bad_cap;
+
+	ceph_dentry_cachep = KMEM_CACHE(ceph_dentry_info,
+					SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (ceph_dentry_cachep == NULL)
+		goto bad_dentry;
+
+	ceph_file_cachep = KMEM_CACHE(ceph_file_info,
+				      SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (ceph_file_cachep == NULL)
+		goto bad_file;
+
+	if ((error = ceph_fscache_register()))
+		goto bad_file;
+
+	return 0;
+bad_file:
+	kmem_cache_destroy(ceph_dentry_cachep);
+bad_dentry:
+	kmem_cache_destroy(ceph_cap_cachep);
+bad_cap:
+	kmem_cache_destroy(ceph_inode_cachep);
+	return error;
+}
+
+static void destroy_caches(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+
+	kmem_cache_destroy(ceph_inode_cachep);
+	kmem_cache_destroy(ceph_cap_cachep);
+	kmem_cache_destroy(ceph_dentry_cachep);
+	kmem_cache_destroy(ceph_file_cachep);
+
+	ceph_fscache_unregister();
+}
+
+
+/*
+ * ceph_umount_begin - initiate forced umount.  Tear down down the
+ * mount, skipping steps that may hang while waiting for server(s).
+ */
+static void ceph_umount_begin(struct super_block *sb)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+
+	dout("ceph_umount_begin - starting forced umount\n");
+	if (!fsc)
+		return;
+	fsc->mount_state = CEPH_MOUNT_SHUTDOWN;
+	return;
+}
+
+static const struct super_operations ceph_super_ops = {
+	.alloc_inode	= ceph_alloc_inode,
+	.destroy_inode	= ceph_destroy_inode,
+	.write_inode    = ceph_write_inode,
+	.drop_inode	= ceph_drop_inode,
+	.sync_fs        = ceph_sync_fs,
+	.put_super	= ceph_put_super,
+	.show_options   = ceph_show_options,
+	.statfs		= ceph_statfs,
+	.umount_begin   = ceph_umount_begin,
+};
+
+/*
+ * Bootstrap mount by opening the root directory.  Note the mount
+ * @started time from caller, and time out if this takes too long.
+ */
+static struct dentry *open_root_dentry(struct ceph_fs_client *fsc,
+				       const char *path,
+				       unsigned long started)
+{
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req = NULL;
+	int err;
+	struct dentry *root;
+
+	/* open dir */
+	dout("open_root_inode opening '%s'\n", path);
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
+	if (IS_ERR(req))
+		return ERR_CAST(req);
+	req->r_path1 = kstrdup(path, GFP_NOFS);
+	if (!req->r_path1) {
+		root = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	req->r_ino1.ino = CEPH_INO_ROOT;
+	req->r_ino1.snap = CEPH_NOSNAP;
+	req->r_started = started;
+	req->r_timeout = fsc->client->options->mount_timeout * HZ;
+	req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INODE);
+	req->r_num_caps = 2;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	if (err == 0) {
+		struct inode *inode = req->r_target_inode;
+		req->r_target_inode = NULL;
+		dout("open_root_inode success\n");
+		if (ceph_ino(inode) == CEPH_INO_ROOT &&
+		    fsc->sb->s_root == NULL) {
+			root = d_make_root(inode);
+			if (!root) {
+				root = ERR_PTR(-ENOMEM);
+				goto out;
+			}
+		} else {
+			root = d_obtain_root(inode);
+		}
+		ceph_init_dentry(root);
+		dout("open_root_inode success, root dentry is %p\n", root);
+	} else {
+		root = ERR_PTR(err);
+	}
+out:
+	ceph_mdsc_put_request(req);
+	return root;
+}
+
+
+
+
+/*
+ * mount: join the ceph cluster, and open root directory.
+ */
+static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc,
+		      const char *path)
+{
+	int err;
+	unsigned long started = jiffies;  /* note the start time */
+	struct dentry *root;
+	int first = 0;   /* first vfsmount for this super_block */
+
+	dout("mount start\n");
+	mutex_lock(&fsc->client->mount_mutex);
+
+	err = __ceph_open_session(fsc->client, started);
+	if (err < 0)
+		goto out;
+
+	dout("mount opening root\n");
+	root = open_root_dentry(fsc, "", started);
+	if (IS_ERR(root)) {
+		err = PTR_ERR(root);
+		goto out;
+	}
+	if (fsc->sb->s_root) {
+		dput(root);
+	} else {
+		fsc->sb->s_root = root;
+		first = 1;
+
+		err = ceph_fs_debugfs_init(fsc);
+		if (err < 0)
+			goto fail;
+	}
+
+	if (path[0] == 0) {
+		dget(root);
+	} else {
+		dout("mount opening base mountpoint\n");
+		root = open_root_dentry(fsc, path, started);
+		if (IS_ERR(root)) {
+			err = PTR_ERR(root);
+			goto fail;
+		}
+	}
+
+	fsc->mount_state = CEPH_MOUNT_MOUNTED;
+	dout("mount success\n");
+	mutex_unlock(&fsc->client->mount_mutex);
+	return root;
+
+out:
+	mutex_unlock(&fsc->client->mount_mutex);
+	return ERR_PTR(err);
+
+fail:
+	if (first) {
+		dput(fsc->sb->s_root);
+		fsc->sb->s_root = NULL;
+	}
+	goto out;
+}
+
+static int ceph_set_super(struct super_block *s, void *data)
+{
+	struct ceph_fs_client *fsc = data;
+	int ret;
+
+	dout("set_super %p data %p\n", s, data);
+
+	s->s_flags = fsc->mount_options->sb_flags;
+	s->s_maxbytes = 1ULL << 40;  /* temp value until we get mdsmap */
+
+	s->s_xattr = ceph_xattr_handlers;
+	s->s_fs_info = fsc;
+	fsc->sb = s;
+
+	s->s_op = &ceph_super_ops;
+	s->s_export_op = &ceph_export_ops;
+
+	s->s_time_gran = 1000;  /* 1000 ns == 1 us */
+
+	ret = set_anon_super(s, NULL);  /* what is that second arg for? */
+	if (ret != 0)
+		goto fail;
+
+	return ret;
+
+fail:
+	s->s_fs_info = NULL;
+	fsc->sb = NULL;
+	return ret;
+}
+
+/*
+ * share superblock if same fs AND options
+ */
+static int ceph_compare_super(struct super_block *sb, void *data)
+{
+	struct ceph_fs_client *new = data;
+	struct ceph_mount_options *fsopt = new->mount_options;
+	struct ceph_options *opt = new->client->options;
+	struct ceph_fs_client *other = ceph_sb_to_client(sb);
+
+	dout("ceph_compare_super %p\n", sb);
+
+	if (compare_mount_options(fsopt, opt, other)) {
+		dout("monitor(s)/mount options don't match\n");
+		return 0;
+	}
+	if ((opt->flags & CEPH_OPT_FSID) &&
+	    ceph_fsid_compare(&opt->fsid, &other->client->fsid)) {
+		dout("fsid doesn't match\n");
+		return 0;
+	}
+	if (fsopt->sb_flags != other->mount_options->sb_flags) {
+		dout("flags differ\n");
+		return 0;
+	}
+	return 1;
+}
+
+/*
+ * construct our own bdi so we can control readahead, etc.
+ */
+static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
+static int ceph_register_bdi(struct super_block *sb,
+			     struct ceph_fs_client *fsc)
+{
+	int err;
+
+	/* set ra_pages based on rasize mount option? */
+	if (fsc->mount_options->rasize >= PAGE_CACHE_SIZE)
+		fsc->backing_dev_info.ra_pages =
+			(fsc->mount_options->rasize + PAGE_CACHE_SIZE - 1)
+			>> PAGE_SHIFT;
+	else
+		fsc->backing_dev_info.ra_pages =
+			VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE;
+
+	err = bdi_register(&fsc->backing_dev_info, NULL, "ceph-%ld",
+			   atomic_long_inc_return(&bdi_seq));
+	if (!err)
+		sb->s_bdi = &fsc->backing_dev_info;
+	return err;
+}
+
+static struct dentry *ceph_mount(struct file_system_type *fs_type,
+		       int flags, const char *dev_name, void *data)
+{
+	struct super_block *sb;
+	struct ceph_fs_client *fsc;
+	struct dentry *res;
+	int err;
+	int (*compare_super)(struct super_block *, void *) = ceph_compare_super;
+	const char *path = NULL;
+	struct ceph_mount_options *fsopt = NULL;
+	struct ceph_options *opt = NULL;
+
+	dout("ceph_mount\n");
+
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+	flags |= MS_POSIXACL;
+#endif
+	err = parse_mount_options(&fsopt, &opt, flags, data, dev_name, &path);
+	if (err < 0) {
+		res = ERR_PTR(err);
+		goto out_final;
+	}
+
+	/* create client (which we may/may not use) */
+	fsc = create_fs_client(fsopt, opt);
+	if (IS_ERR(fsc)) {
+		res = ERR_CAST(fsc);
+		destroy_mount_options(fsopt);
+		ceph_destroy_options(opt);
+		goto out_final;
+	}
+
+	err = ceph_mdsc_init(fsc);
+	if (err < 0) {
+		res = ERR_PTR(err);
+		goto out;
+	}
+
+	if (ceph_test_opt(fsc->client, NOSHARE))
+		compare_super = NULL;
+	sb = sget(fs_type, compare_super, ceph_set_super, flags, fsc);
+	if (IS_ERR(sb)) {
+		res = ERR_CAST(sb);
+		goto out;
+	}
+
+	if (ceph_sb_to_client(sb) != fsc) {
+		ceph_mdsc_destroy(fsc);
+		destroy_fs_client(fsc);
+		fsc = ceph_sb_to_client(sb);
+		dout("get_sb got existing client %p\n", fsc);
+	} else {
+		dout("get_sb using new client %p\n", fsc);
+		err = ceph_register_bdi(sb, fsc);
+		if (err < 0) {
+			res = ERR_PTR(err);
+			goto out_splat;
+		}
+	}
+
+	res = ceph_real_mount(fsc, path);
+	if (IS_ERR(res))
+		goto out_splat;
+	dout("root %p inode %p ino %llx.%llx\n", res,
+	     d_inode(res), ceph_vinop(d_inode(res)));
+	return res;
+
+out_splat:
+	ceph_mdsc_close_sessions(fsc->mdsc);
+	deactivate_locked_super(sb);
+	goto out_final;
+
+out:
+	ceph_mdsc_destroy(fsc);
+	destroy_fs_client(fsc);
+out_final:
+	dout("ceph_mount fail %ld\n", PTR_ERR(res));
+	return res;
+}
+
+static void ceph_kill_sb(struct super_block *s)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(s);
+	dev_t dev = s->s_dev;
+
+	dout("kill_sb %p\n", s);
+
+	ceph_mdsc_pre_umount(fsc->mdsc);
+	generic_shutdown_super(s);
+	ceph_mdsc_destroy(fsc);
+
+	destroy_fs_client(fsc);
+	free_anon_bdev(dev);
+}
+
+static struct file_system_type ceph_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "ceph",
+	.mount		= ceph_mount,
+	.kill_sb	= ceph_kill_sb,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE,
+};
+MODULE_ALIAS_FS("ceph");
+
+static int __init init_ceph(void)
+{
+	int ret = init_caches();
+	if (ret)
+		goto out;
+
+	ceph_flock_init();
+	ceph_xattr_init();
+	ret = ceph_snap_init();
+	if (ret)
+		goto out_xattr;
+	ret = register_filesystem(&ceph_fs_type);
+	if (ret)
+		goto out_snap;
+
+	pr_info("loaded (mds proto %d)\n", CEPH_MDSC_PROTOCOL);
+
+	return 0;
+
+out_snap:
+	ceph_snap_exit();
+out_xattr:
+	ceph_xattr_exit();
+	destroy_caches();
+out:
+	return ret;
+}
+
+static void __exit exit_ceph(void)
+{
+	dout("exit_ceph\n");
+	unregister_filesystem(&ceph_fs_type);
+	ceph_snap_exit();
+	ceph_xattr_exit();
+	destroy_caches();
+}
+
+module_init(init_ceph);
+module_exit(exit_ceph);
+
+MODULE_AUTHOR("Sage Weil <sage@newdream.net>");
+MODULE_AUTHOR("Yehuda Sadeh <yehuda@hq.newdream.net>");
+MODULE_AUTHOR("Patience Warnick <patience@newdream.net>");
+MODULE_DESCRIPTION("Ceph filesystem for Linux");
+MODULE_LICENSE("GPL");
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
new file mode 100644
index 000000000..fa20e1318
--- /dev/null
+++ b/fs/ceph/super.h
@@ -0,0 +1,946 @@
+#ifndef _FS_CEPH_SUPER_H
+#define _FS_CEPH_SUPER_H
+
+#include <linux/ceph/ceph_debug.h>
+
+#include <asm/unaligned.h>
+#include <linux/backing-dev.h>
+#include <linux/completion.h>
+#include <linux/exportfs.h>
+#include <linux/fs.h>
+#include <linux/mempool.h>
+#include <linux/pagemap.h>
+#include <linux/wait.h>
+#include <linux/writeback.h>
+#include <linux/slab.h>
+#include <linux/posix_acl.h>
+
+#include <linux/ceph/libceph.h>
+
+#ifdef CONFIG_CEPH_FSCACHE
+#include <linux/fscache.h>
+#endif
+
+/* f_type in struct statfs */
+#define CEPH_SUPER_MAGIC 0x00c36400
+
+/* large granularity for statfs utilization stats to facilitate
+ * large volume sizes on 32-bit machines. */
+#define CEPH_BLOCK_SHIFT   22  /* 4 MB */
+#define CEPH_BLOCK         (1 << CEPH_BLOCK_SHIFT)
+
+#define CEPH_MOUNT_OPT_DIRSTAT         (1<<4) /* `cat dirname` for stats */
+#define CEPH_MOUNT_OPT_RBYTES          (1<<5) /* dir st_bytes = rbytes */
+#define CEPH_MOUNT_OPT_NOASYNCREADDIR  (1<<7) /* no dcache readdir */
+#define CEPH_MOUNT_OPT_INO32           (1<<8) /* 32 bit inos */
+#define CEPH_MOUNT_OPT_DCACHE          (1<<9) /* use dcache for readdir etc */
+#define CEPH_MOUNT_OPT_FSCACHE         (1<<10) /* use fscache */
+
+#define CEPH_MOUNT_OPT_DEFAULT    (CEPH_MOUNT_OPT_RBYTES | \
+				   CEPH_MOUNT_OPT_DCACHE)
+
+#define ceph_set_mount_opt(fsc, opt) \
+	(fsc)->mount_options->flags |= CEPH_MOUNT_OPT_##opt;
+#define ceph_test_mount_opt(fsc, opt) \
+	(!!((fsc)->mount_options->flags & CEPH_MOUNT_OPT_##opt))
+
+#define CEPH_RSIZE_DEFAULT             0           /* max read size */
+#define CEPH_RASIZE_DEFAULT            (8192*1024) /* readahead */
+#define CEPH_MAX_READDIR_DEFAULT        1024
+#define CEPH_MAX_READDIR_BYTES_DEFAULT  (512*1024)
+#define CEPH_SNAPDIRNAME_DEFAULT        ".snap"
+
+struct ceph_mount_options {
+	int flags;
+	int sb_flags;
+
+	int wsize;            /* max write size */
+	int rsize;            /* max read size */
+	int rasize;           /* max readahead */
+	int congestion_kb;    /* max writeback in flight */
+	int caps_wanted_delay_min, caps_wanted_delay_max;
+	int cap_release_safety;
+	int max_readdir;       /* max readdir result (entires) */
+	int max_readdir_bytes; /* max readdir result (bytes) */
+
+	/*
+	 * everything above this point can be memcmp'd; everything below
+	 * is handled in compare_mount_options()
+	 */
+
+	char *snapdir_name;   /* default ".snap" */
+};
+
+struct ceph_fs_client {
+	struct super_block *sb;
+
+	struct ceph_mount_options *mount_options;
+	struct ceph_client *client;
+
+	unsigned long mount_state;
+	int min_caps;                  /* min caps i added */
+
+	struct ceph_mds_client *mdsc;
+
+	/* writeback */
+	mempool_t *wb_pagevec_pool;
+	struct workqueue_struct *wb_wq;
+	struct workqueue_struct *pg_inv_wq;
+	struct workqueue_struct *trunc_wq;
+	atomic_long_t writeback_count;
+
+	struct backing_dev_info backing_dev_info;
+
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *debugfs_dentry_lru, *debugfs_caps;
+	struct dentry *debugfs_congestion_kb;
+	struct dentry *debugfs_bdi;
+	struct dentry *debugfs_mdsc, *debugfs_mdsmap;
+	struct dentry *debugfs_mds_sessions;
+#endif
+
+#ifdef CONFIG_CEPH_FSCACHE
+	struct fscache_cookie *fscache;
+	struct workqueue_struct *revalidate_wq;
+#endif
+};
+
+
+/*
+ * File i/o capability.  This tracks shared state with the metadata
+ * server that allows us to cache or writeback attributes or to read
+ * and write data.  For any given inode, we should have one or more
+ * capabilities, one issued by each metadata server, and our
+ * cumulative access is the OR of all issued capabilities.
+ *
+ * Each cap is referenced by the inode's i_caps rbtree and by per-mds
+ * session capability lists.
+ */
+struct ceph_cap {
+	struct ceph_inode_info *ci;
+	struct rb_node ci_node;          /* per-ci cap tree */
+	struct ceph_mds_session *session;
+	struct list_head session_caps;   /* per-session caplist */
+	int mds;
+	u64 cap_id;       /* unique cap id (mds provided) */
+	int issued;       /* latest, from the mds */
+	int implemented;  /* implemented superset of issued (for revocation) */
+	int mds_wanted;
+	u32 seq, issue_seq, mseq;
+	u32 cap_gen;      /* active/stale cycle */
+	unsigned long last_used;
+	struct list_head caps_item;
+};
+
+#define CHECK_CAPS_NODELAY    1  /* do not delay any further */
+#define CHECK_CAPS_AUTHONLY   2  /* only check auth cap */
+#define CHECK_CAPS_FLUSH      4  /* flush any dirty caps */
+
+/*
+ * Snapped cap state that is pending flush to mds.  When a snapshot occurs,
+ * we first complete any in-process sync writes and writeback any dirty
+ * data before flushing the snapped state (tracked here) back to the MDS.
+ */
+struct ceph_cap_snap {
+	atomic_t nref;
+	struct ceph_inode_info *ci;
+	struct list_head ci_item, flushing_item;
+
+	u64 follows, flush_tid;
+	int issued, dirty;
+	struct ceph_snap_context *context;
+
+	umode_t mode;
+	kuid_t uid;
+	kgid_t gid;
+
+	struct ceph_buffer *xattr_blob;
+	u64 xattr_version;
+
+	u64 size;
+	struct timespec mtime, atime, ctime;
+	u64 time_warp_seq;
+	int writing;   /* a sync write is still in progress */
+	int dirty_pages;     /* dirty pages awaiting writeback */
+	bool inline_data;
+};
+
+static inline void ceph_put_cap_snap(struct ceph_cap_snap *capsnap)
+{
+	if (atomic_dec_and_test(&capsnap->nref)) {
+		if (capsnap->xattr_blob)
+			ceph_buffer_put(capsnap->xattr_blob);
+		kfree(capsnap);
+	}
+}
+
+/*
+ * The frag tree describes how a directory is fragmented, potentially across
+ * multiple metadata servers.  It is also used to indicate points where
+ * metadata authority is delegated, and whether/where metadata is replicated.
+ *
+ * A _leaf_ frag will be present in the i_fragtree IFF there is
+ * delegation info.  That is, if mds >= 0 || ndist > 0.
+ */
+#define CEPH_MAX_DIRFRAG_REP 4
+
+struct ceph_inode_frag {
+	struct rb_node node;
+
+	/* fragtree state */
+	u32 frag;
+	int split_by;         /* i.e. 2^(split_by) children */
+
+	/* delegation and replication info */
+	int mds;              /* -1 if same authority as parent */
+	int ndist;            /* >0 if replicated */
+	int dist[CEPH_MAX_DIRFRAG_REP];
+};
+
+/*
+ * We cache inode xattrs as an encoded blob until they are first used,
+ * at which point we parse them into an rbtree.
+ */
+struct ceph_inode_xattr {
+	struct rb_node node;
+
+	const char *name;
+	int name_len;
+	const char *val;
+	int val_len;
+	int dirty;
+
+	int should_free_name;
+	int should_free_val;
+};
+
+/*
+ * Ceph dentry state
+ */
+struct ceph_dentry_info {
+	struct ceph_mds_session *lease_session;
+	u32 lease_gen, lease_shared_gen;
+	u32 lease_seq;
+	unsigned long lease_renew_after, lease_renew_from;
+	struct list_head lru;
+	struct dentry *dentry;
+	u64 time;
+	u64 offset;
+};
+
+struct ceph_inode_xattrs_info {
+	/*
+	 * (still encoded) xattr blob. we avoid the overhead of parsing
+	 * this until someone actually calls getxattr, etc.
+	 *
+	 * blob->vec.iov_len == 4 implies there are no xattrs; blob ==
+	 * NULL means we don't know.
+	*/
+	struct ceph_buffer *blob, *prealloc_blob;
+
+	struct rb_root index;
+	bool dirty;
+	int count;
+	int names_size;
+	int vals_size;
+	u64 version, index_version;
+};
+
+/*
+ * Ceph inode.
+ */
+struct ceph_inode_info {
+	struct ceph_vino i_vino;   /* ceph ino + snap */
+
+	spinlock_t i_ceph_lock;
+
+	u64 i_version;
+	u64 i_inline_version;
+	u32 i_time_warp_seq;
+
+	unsigned i_ceph_flags;
+	int i_ordered_count;
+	atomic_t i_release_count;
+	atomic_t i_complete_count;
+
+	struct ceph_dir_layout i_dir_layout;
+	struct ceph_file_layout i_layout;
+	char *i_symlink;
+
+	/* for dirs */
+	struct timespec i_rctime;
+	u64 i_rbytes, i_rfiles, i_rsubdirs;
+	u64 i_files, i_subdirs;
+
+	struct rb_root i_fragtree;
+	struct mutex i_fragtree_mutex;
+
+	struct ceph_inode_xattrs_info i_xattrs;
+
+	/* capabilities.  protected _both_ by i_ceph_lock and cap->session's
+	 * s_mutex. */
+	struct rb_root i_caps;           /* cap list */
+	struct ceph_cap *i_auth_cap;     /* authoritative cap, if any */
+	unsigned i_dirty_caps, i_flushing_caps;     /* mask of dirtied fields */
+	struct list_head i_dirty_item, i_flushing_item;
+	u64 i_cap_flush_seq;
+	/* we need to track cap writeback on a per-cap-bit basis, to allow
+	 * overlapping, pipelined cap flushes to the mds.  we can probably
+	 * reduce the tid to 8 bits if we're concerned about inode size. */
+	u16 i_cap_flush_last_tid, i_cap_flush_tid[CEPH_CAP_BITS];
+	wait_queue_head_t i_cap_wq;      /* threads waiting on a capability */
+	unsigned long i_hold_caps_min; /* jiffies */
+	unsigned long i_hold_caps_max; /* jiffies */
+	struct list_head i_cap_delay_list;  /* for delayed cap release to mds */
+	struct ceph_cap_reservation i_cap_migration_resv;
+	struct list_head i_cap_snaps;   /* snapped state pending flush to mds */
+	struct ceph_snap_context *i_head_snapc;  /* set if wr_buffer_head > 0 or
+						    dirty|flushing caps */
+	unsigned i_snap_caps;           /* cap bits for snapped files */
+
+	int i_nr_by_mode[CEPH_FILE_MODE_NUM];  /* open file counts */
+
+	struct mutex i_truncate_mutex;
+	u32 i_truncate_seq;        /* last truncate to smaller size */
+	u64 i_truncate_size;       /*  and the size we last truncated down to */
+	int i_truncate_pending;    /*  still need to call vmtruncate */
+
+	u64 i_max_size;            /* max file size authorized by mds */
+	u64 i_reported_size; /* (max_)size reported to or requested of mds */
+	u64 i_wanted_max_size;     /* offset we'd like to write too */
+	u64 i_requested_max_size;  /* max_size we've requested */
+
+	/* held references to caps */
+	int i_pin_ref;
+	int i_rd_ref, i_rdcache_ref, i_wr_ref, i_wb_ref;
+	int i_wrbuffer_ref, i_wrbuffer_ref_head;
+	u32 i_shared_gen;       /* increment each time we get FILE_SHARED */
+	u32 i_rdcache_gen;      /* incremented each time we get FILE_CACHE. */
+	u32 i_rdcache_revoking; /* RDCACHE gen to async invalidate, if any */
+
+	struct list_head i_unsafe_writes; /* uncommitted sync writes */
+	struct list_head i_unsafe_dirops; /* uncommitted mds dir ops */
+	spinlock_t i_unsafe_lock;
+
+	struct ceph_snap_realm *i_snap_realm; /* snap realm (if caps) */
+	int i_snap_realm_counter; /* snap realm (if caps) */
+	struct list_head i_snap_realm_item;
+	struct list_head i_snap_flush_item;
+
+	struct work_struct i_wb_work;  /* writeback work */
+	struct work_struct i_pg_inv_work;  /* page invalidation work */
+
+	struct work_struct i_vmtruncate_work;
+
+#ifdef CONFIG_CEPH_FSCACHE
+	struct fscache_cookie *fscache;
+	u32 i_fscache_gen; /* sequence, for delayed fscache validate */
+	struct work_struct i_revalidate_work;
+#endif
+	struct inode vfs_inode; /* at end */
+};
+
+static inline struct ceph_inode_info *ceph_inode(struct inode *inode)
+{
+	return container_of(inode, struct ceph_inode_info, vfs_inode);
+}
+
+static inline struct ceph_fs_client *ceph_inode_to_client(struct inode *inode)
+{
+	return (struct ceph_fs_client *)inode->i_sb->s_fs_info;
+}
+
+static inline struct ceph_fs_client *ceph_sb_to_client(struct super_block *sb)
+{
+	return (struct ceph_fs_client *)sb->s_fs_info;
+}
+
+static inline struct ceph_vino ceph_vino(struct inode *inode)
+{
+	return ceph_inode(inode)->i_vino;
+}
+
+/*
+ * ino_t is <64 bits on many architectures, blech.
+ *
+ *               i_ino (kernel inode)   st_ino (userspace)
+ * i386          32                     32
+ * x86_64+ino32  64                     32
+ * x86_64        64                     64
+ */
+static inline u32 ceph_ino_to_ino32(__u64 vino)
+{
+	u32 ino = vino & 0xffffffff;
+	ino ^= vino >> 32;
+	if (!ino)
+		ino = 2;
+	return ino;
+}
+
+/*
+ * kernel i_ino value
+ */
+static inline ino_t ceph_vino_to_ino(struct ceph_vino vino)
+{
+#if BITS_PER_LONG == 32
+	return ceph_ino_to_ino32(vino.ino);
+#else
+	return (ino_t)vino.ino;
+#endif
+}
+
+/*
+ * user-visible ino (stat, filldir)
+ */
+#if BITS_PER_LONG == 32
+static inline ino_t ceph_translate_ino(struct super_block *sb, ino_t ino)
+{
+	return ino;
+}
+#else
+static inline ino_t ceph_translate_ino(struct super_block *sb, ino_t ino)
+{
+	if (ceph_test_mount_opt(ceph_sb_to_client(sb), INO32))
+		ino = ceph_ino_to_ino32(ino);
+	return ino;
+}
+#endif
+
+
+/* for printf-style formatting */
+#define ceph_vinop(i) ceph_inode(i)->i_vino.ino, ceph_inode(i)->i_vino.snap
+
+static inline u64 ceph_ino(struct inode *inode)
+{
+	return ceph_inode(inode)->i_vino.ino;
+}
+static inline u64 ceph_snap(struct inode *inode)
+{
+	return ceph_inode(inode)->i_vino.snap;
+}
+
+static inline int ceph_ino_compare(struct inode *inode, void *data)
+{
+	struct ceph_vino *pvino = (struct ceph_vino *)data;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	return ci->i_vino.ino == pvino->ino &&
+		ci->i_vino.snap == pvino->snap;
+}
+
+static inline struct inode *ceph_find_inode(struct super_block *sb,
+					    struct ceph_vino vino)
+{
+	ino_t t = ceph_vino_to_ino(vino);
+	return ilookup5(sb, t, ceph_ino_compare, &vino);
+}
+
+
+/*
+ * Ceph inode.
+ */
+#define CEPH_I_DIR_ORDERED	1  /* dentries in dir are ordered */
+#define CEPH_I_NODELAY		4  /* do not delay cap release */
+#define CEPH_I_FLUSH		8  /* do not delay flush of dirty metadata */
+#define CEPH_I_NOFLUSH		16 /* do not flush dirty caps */
+
+static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
+					   int release_count, int ordered_count)
+{
+	atomic_set(&ci->i_complete_count, release_count);
+	if (ci->i_ordered_count == ordered_count)
+		ci->i_ceph_flags |= CEPH_I_DIR_ORDERED;
+	else
+		ci->i_ceph_flags &= ~CEPH_I_DIR_ORDERED;
+}
+
+static inline void __ceph_dir_clear_complete(struct ceph_inode_info *ci)
+{
+	atomic_inc(&ci->i_release_count);
+}
+
+static inline bool __ceph_dir_is_complete(struct ceph_inode_info *ci)
+{
+	return atomic_read(&ci->i_complete_count) ==
+		atomic_read(&ci->i_release_count);
+}
+
+static inline bool __ceph_dir_is_complete_ordered(struct ceph_inode_info *ci)
+{
+	return __ceph_dir_is_complete(ci) &&
+		(ci->i_ceph_flags & CEPH_I_DIR_ORDERED);
+}
+
+static inline void ceph_dir_clear_complete(struct inode *inode)
+{
+	__ceph_dir_clear_complete(ceph_inode(inode));
+}
+
+static inline void ceph_dir_clear_ordered(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	spin_lock(&ci->i_ceph_lock);
+	ci->i_ordered_count++;
+	ci->i_ceph_flags &= ~CEPH_I_DIR_ORDERED;
+	spin_unlock(&ci->i_ceph_lock);
+}
+
+static inline bool ceph_dir_is_complete_ordered(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	bool ret;
+	spin_lock(&ci->i_ceph_lock);
+	ret = __ceph_dir_is_complete_ordered(ci);
+	spin_unlock(&ci->i_ceph_lock);
+	return ret;
+}
+
+/* find a specific frag @f */
+extern struct ceph_inode_frag *__ceph_find_frag(struct ceph_inode_info *ci,
+						u32 f);
+
+/*
+ * choose fragment for value @v.  copy frag content to pfrag, if leaf
+ * exists
+ */
+extern u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
+			    struct ceph_inode_frag *pfrag,
+			    int *found);
+
+static inline struct ceph_dentry_info *ceph_dentry(struct dentry *dentry)
+{
+	return (struct ceph_dentry_info *)dentry->d_fsdata;
+}
+
+static inline loff_t ceph_make_fpos(unsigned frag, unsigned off)
+{
+	return ((loff_t)frag << 32) | (loff_t)off;
+}
+
+/*
+ * caps helpers
+ */
+static inline bool __ceph_is_any_real_caps(struct ceph_inode_info *ci)
+{
+	return !RB_EMPTY_ROOT(&ci->i_caps);
+}
+
+extern int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented);
+extern int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int t);
+extern int __ceph_caps_issued_other(struct ceph_inode_info *ci,
+				    struct ceph_cap *cap);
+
+static inline int ceph_caps_issued(struct ceph_inode_info *ci)
+{
+	int issued;
+	spin_lock(&ci->i_ceph_lock);
+	issued = __ceph_caps_issued(ci, NULL);
+	spin_unlock(&ci->i_ceph_lock);
+	return issued;
+}
+
+static inline int ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask,
+					int touch)
+{
+	int r;
+	spin_lock(&ci->i_ceph_lock);
+	r = __ceph_caps_issued_mask(ci, mask, touch);
+	spin_unlock(&ci->i_ceph_lock);
+	return r;
+}
+
+static inline int __ceph_caps_dirty(struct ceph_inode_info *ci)
+{
+	return ci->i_dirty_caps | ci->i_flushing_caps;
+}
+extern int __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask);
+
+extern int __ceph_caps_revoking_other(struct ceph_inode_info *ci,
+				      struct ceph_cap *ocap, int mask);
+extern int ceph_caps_revoking(struct ceph_inode_info *ci, int mask);
+extern int __ceph_caps_used(struct ceph_inode_info *ci);
+
+extern int __ceph_caps_file_wanted(struct ceph_inode_info *ci);
+
+/*
+ * wanted, by virtue of open file modes AND cap refs (buffered/cached data)
+ */
+static inline int __ceph_caps_wanted(struct ceph_inode_info *ci)
+{
+	int w = __ceph_caps_file_wanted(ci) | __ceph_caps_used(ci);
+	if (w & CEPH_CAP_FILE_BUFFER)
+		w |= CEPH_CAP_FILE_EXCL;  /* we want EXCL if dirty data */
+	return w;
+}
+
+/* what the mds thinks we want */
+extern int __ceph_caps_mds_wanted(struct ceph_inode_info *ci);
+
+extern void ceph_caps_init(struct ceph_mds_client *mdsc);
+extern void ceph_caps_finalize(struct ceph_mds_client *mdsc);
+extern void ceph_adjust_min_caps(struct ceph_mds_client *mdsc, int delta);
+extern void ceph_reserve_caps(struct ceph_mds_client *mdsc,
+			     struct ceph_cap_reservation *ctx, int need);
+extern int ceph_unreserve_caps(struct ceph_mds_client *mdsc,
+			       struct ceph_cap_reservation *ctx);
+extern void ceph_reservation_status(struct ceph_fs_client *client,
+				    int *total, int *avail, int *used,
+				    int *reserved, int *min);
+
+
+
+/*
+ * we keep buffered readdir results attached to file->private_data
+ */
+#define CEPH_F_SYNC     1
+#define CEPH_F_ATEND    2
+
+struct ceph_file_info {
+	short fmode;     /* initialized on open */
+	short flags;     /* CEPH_F_* */
+
+	/* readdir: position within the dir */
+	u32 frag;
+	struct ceph_mds_request *last_readdir;
+
+	/* readdir: position within a frag */
+	unsigned offset;       /* offset of last chunk, adjusted for . and .. */
+	unsigned next_offset;  /* offset of next chunk (last_name's + 1) */
+	char *last_name;       /* last entry in previous chunk */
+	struct dentry *dentry; /* next dentry (for dcache readdir) */
+	int dir_release_count;
+	int dir_ordered_count;
+
+	/* used for -o dirstat read() on directory thing */
+	char *dir_info;
+	int dir_info_len;
+};
+
+
+
+/*
+ * A "snap realm" describes a subset of the file hierarchy sharing
+ * the same set of snapshots that apply to it.  The realms themselves
+ * are organized into a hierarchy, such that children inherit (some of)
+ * the snapshots of their parents.
+ *
+ * All inodes within the realm that have capabilities are linked into a
+ * per-realm list.
+ */
+struct ceph_snap_realm {
+	u64 ino;
+	atomic_t nref;
+	struct rb_node node;
+
+	u64 created, seq;
+	u64 parent_ino;
+	u64 parent_since;   /* snapid when our current parent became so */
+
+	u64 *prior_parent_snaps;      /* snaps inherited from any parents we */
+	u32 num_prior_parent_snaps;   /*  had prior to parent_since */
+	u64 *snaps;                   /* snaps specific to this realm */
+	u32 num_snaps;
+
+	struct ceph_snap_realm *parent;
+	struct list_head children;       /* list of child realms */
+	struct list_head child_item;
+
+	struct list_head empty_item;     /* if i have ref==0 */
+
+	struct list_head dirty_item;     /* if realm needs new context */
+
+	/* the current set of snaps for this realm */
+	struct ceph_snap_context *cached_context;
+
+	struct list_head inodes_with_caps;
+	spinlock_t inodes_with_caps_lock;
+};
+
+static inline int default_congestion_kb(void)
+{
+	int congestion_kb;
+
+	/*
+	 * Copied from NFS
+	 *
+	 * congestion size, scale with available memory.
+	 *
+	 *  64MB:    8192k
+	 * 128MB:   11585k
+	 * 256MB:   16384k
+	 * 512MB:   23170k
+	 *   1GB:   32768k
+	 *   2GB:   46340k
+	 *   4GB:   65536k
+	 *   8GB:   92681k
+	 *  16GB:  131072k
+	 *
+	 * This allows larger machines to have larger/more transfers.
+	 * Limit the default to 256M
+	 */
+	congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
+	if (congestion_kb > 256*1024)
+		congestion_kb = 256*1024;
+
+	return congestion_kb;
+}
+
+
+
+/* snap.c */
+struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
+					       u64 ino);
+extern void ceph_get_snap_realm(struct ceph_mds_client *mdsc,
+				struct ceph_snap_realm *realm);
+extern void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
+				struct ceph_snap_realm *realm);
+extern int ceph_update_snap_trace(struct ceph_mds_client *m,
+				  void *p, void *e, bool deletion,
+				  struct ceph_snap_realm **realm_ret);
+extern void ceph_handle_snap(struct ceph_mds_client *mdsc,
+			     struct ceph_mds_session *session,
+			     struct ceph_msg *msg);
+extern void ceph_queue_cap_snap(struct ceph_inode_info *ci);
+extern int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
+				  struct ceph_cap_snap *capsnap);
+extern void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc);
+extern int ceph_snap_init(void);
+extern void ceph_snap_exit(void);
+
+/*
+ * a cap_snap is "pending" if it is still awaiting an in-progress
+ * sync write (that may/may not still update size, mtime, etc.).
+ */
+static inline bool __ceph_have_pending_cap_snap(struct ceph_inode_info *ci)
+{
+	return !list_empty(&ci->i_cap_snaps) &&
+		list_entry(ci->i_cap_snaps.prev, struct ceph_cap_snap,
+			   ci_item)->writing;
+}
+
+/* inode.c */
+extern const struct inode_operations ceph_file_iops;
+
+extern struct inode *ceph_alloc_inode(struct super_block *sb);
+extern void ceph_destroy_inode(struct inode *inode);
+extern int ceph_drop_inode(struct inode *inode);
+
+extern struct inode *ceph_get_inode(struct super_block *sb,
+				    struct ceph_vino vino);
+extern struct inode *ceph_get_snapdir(struct inode *parent);
+extern int ceph_fill_file_size(struct inode *inode, int issued,
+			       u32 truncate_seq, u64 truncate_size, u64 size);
+extern void ceph_fill_file_time(struct inode *inode, int issued,
+				u64 time_warp_seq, struct timespec *ctime,
+				struct timespec *mtime, struct timespec *atime);
+extern int ceph_fill_trace(struct super_block *sb,
+			   struct ceph_mds_request *req,
+			   struct ceph_mds_session *session);
+extern int ceph_readdir_prepopulate(struct ceph_mds_request *req,
+				    struct ceph_mds_session *session);
+
+extern int ceph_inode_holds_cap(struct inode *inode, int mask);
+
+extern int ceph_inode_set_size(struct inode *inode, loff_t size);
+extern void __ceph_do_pending_vmtruncate(struct inode *inode);
+extern void ceph_queue_vmtruncate(struct inode *inode);
+
+extern void ceph_queue_invalidate(struct inode *inode);
+extern void ceph_queue_writeback(struct inode *inode);
+
+extern int __ceph_do_getattr(struct inode *inode, struct page *locked_page,
+			     int mask, bool force);
+static inline int ceph_do_getattr(struct inode *inode, int mask, bool force)
+{
+	return __ceph_do_getattr(inode, NULL, mask, force);
+}
+extern int ceph_permission(struct inode *inode, int mask);
+extern int ceph_setattr(struct dentry *dentry, struct iattr *attr);
+extern int ceph_getattr(struct vfsmount *mnt, struct dentry *dentry,
+			struct kstat *stat);
+
+/* xattr.c */
+extern int ceph_setxattr(struct dentry *, const char *, const void *,
+			 size_t, int);
+int __ceph_setxattr(struct dentry *, const char *, const void *, size_t, int);
+ssize_t __ceph_getxattr(struct inode *, const char *, void *, size_t);
+int __ceph_removexattr(struct dentry *, const char *);
+extern ssize_t ceph_getxattr(struct dentry *, const char *, void *, size_t);
+extern ssize_t ceph_listxattr(struct dentry *, char *, size_t);
+extern int ceph_removexattr(struct dentry *, const char *);
+extern void __ceph_build_xattrs_blob(struct ceph_inode_info *ci);
+extern void __ceph_destroy_xattrs(struct ceph_inode_info *ci);
+extern void __init ceph_xattr_init(void);
+extern void ceph_xattr_exit(void);
+extern const struct xattr_handler *ceph_xattr_handlers[];
+
+/* acl.c */
+struct ceph_acls_info {
+	void *default_acl;
+	void *acl;
+	struct ceph_pagelist *pagelist;
+};
+
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+
+struct posix_acl *ceph_get_acl(struct inode *, int);
+int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
+		       struct ceph_acls_info *info);
+void ceph_init_inode_acls(struct inode *inode, struct ceph_acls_info *info);
+void ceph_release_acls_info(struct ceph_acls_info *info);
+
+static inline void ceph_forget_all_cached_acls(struct inode *inode)
+{
+       forget_all_cached_acls(inode);
+}
+
+#else
+
+#define ceph_get_acl NULL
+#define ceph_set_acl NULL
+
+static inline int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
+				     struct ceph_acls_info *info)
+{
+	return 0;
+}
+static inline void ceph_init_inode_acls(struct inode *inode,
+					struct ceph_acls_info *info)
+{
+}
+static inline void ceph_release_acls_info(struct ceph_acls_info *info)
+{
+}
+static inline int ceph_acl_chmod(struct dentry *dentry, struct inode *inode)
+{
+	return 0;
+}
+
+static inline void ceph_forget_all_cached_acls(struct inode *inode)
+{
+}
+
+#endif
+
+/* caps.c */
+extern const char *ceph_cap_string(int c);
+extern void ceph_handle_caps(struct ceph_mds_session *session,
+			     struct ceph_msg *msg);
+extern struct ceph_cap *ceph_get_cap(struct ceph_mds_client *mdsc,
+				     struct ceph_cap_reservation *ctx);
+extern void ceph_add_cap(struct inode *inode,
+			 struct ceph_mds_session *session, u64 cap_id,
+			 int fmode, unsigned issued, unsigned wanted,
+			 unsigned cap, unsigned seq, u64 realmino, int flags,
+			 struct ceph_cap **new_cap);
+extern void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release);
+extern void ceph_put_cap(struct ceph_mds_client *mdsc,
+			 struct ceph_cap *cap);
+extern int ceph_is_any_caps(struct inode *inode);
+
+extern void __queue_cap_release(struct ceph_mds_session *session, u64 ino,
+				u64 cap_id, u32 migrate_seq, u32 issue_seq);
+extern void ceph_queue_caps_release(struct inode *inode);
+extern int ceph_write_inode(struct inode *inode, struct writeback_control *wbc);
+extern int ceph_fsync(struct file *file, loff_t start, loff_t end,
+		      int datasync);
+extern void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
+				    struct ceph_mds_session *session);
+extern struct ceph_cap *ceph_get_cap_for_mds(struct ceph_inode_info *ci,
+					     int mds);
+extern int ceph_get_cap_mds(struct inode *inode);
+extern void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps);
+extern void ceph_put_cap_refs(struct ceph_inode_info *ci, int had);
+extern void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
+				       struct ceph_snap_context *snapc);
+extern void __ceph_flush_snaps(struct ceph_inode_info *ci,
+			       struct ceph_mds_session **psession,
+			       int again);
+extern void ceph_check_caps(struct ceph_inode_info *ci, int flags,
+			    struct ceph_mds_session *session);
+extern void ceph_check_delayed_caps(struct ceph_mds_client *mdsc);
+extern void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc);
+
+extern int ceph_encode_inode_release(void **p, struct inode *inode,
+				     int mds, int drop, int unless, int force);
+extern int ceph_encode_dentry_release(void **p, struct dentry *dn,
+				      int mds, int drop, int unless);
+
+extern int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
+			 loff_t endoff, int *got, struct page **pinned_page);
+
+/* for counting open files by mode */
+static inline void __ceph_get_fmode(struct ceph_inode_info *ci, int mode)
+{
+	ci->i_nr_by_mode[mode]++;
+}
+extern void ceph_put_fmode(struct ceph_inode_info *ci, int mode);
+
+/* addr.c */
+extern const struct address_space_operations ceph_aops;
+extern int ceph_mmap(struct file *file, struct vm_area_struct *vma);
+
+/* file.c */
+extern const struct file_operations ceph_file_fops;
+
+extern int ceph_open(struct inode *inode, struct file *file);
+extern int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
+			    struct file *file, unsigned flags, umode_t mode,
+			    int *opened);
+extern int ceph_release(struct inode *inode, struct file *filp);
+extern void ceph_fill_inline_data(struct inode *inode, struct page *locked_page,
+				  char *data, size_t len);
+int ceph_uninline_data(struct file *filp, struct page *locked_page);
+/* dir.c */
+extern const struct file_operations ceph_dir_fops;
+extern const struct file_operations ceph_snapdir_fops;
+extern const struct inode_operations ceph_dir_iops;
+extern const struct inode_operations ceph_snapdir_iops;
+extern const struct dentry_operations ceph_dentry_ops, ceph_snap_dentry_ops,
+	ceph_snapdir_dentry_ops;
+
+extern int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry);
+extern int ceph_handle_snapdir(struct ceph_mds_request *req,
+			       struct dentry *dentry, int err);
+extern struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
+					 struct dentry *dentry, int err);
+
+extern void ceph_dentry_lru_add(struct dentry *dn);
+extern void ceph_dentry_lru_touch(struct dentry *dn);
+extern void ceph_dentry_lru_del(struct dentry *dn);
+extern void ceph_invalidate_dentry_lease(struct dentry *dentry);
+extern unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn);
+extern struct inode *ceph_get_dentry_parent_inode(struct dentry *dentry);
+
+/*
+ * our d_ops vary depending on whether the inode is live,
+ * snapshotted (read-only), or a virtual ".snap" directory.
+ */
+int ceph_init_dentry(struct dentry *dentry);
+
+
+/* ioctl.c */
+extern long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
+
+/* export.c */
+extern const struct export_operations ceph_export_ops;
+
+/* locks.c */
+extern __init void ceph_flock_init(void);
+extern int ceph_lock(struct file *file, int cmd, struct file_lock *fl);
+extern int ceph_flock(struct file *file, int cmd, struct file_lock *fl);
+extern void ceph_count_locks(struct inode *inode, int *p_num, int *f_num);
+extern int ceph_encode_locks_to_buffer(struct inode *inode,
+				       struct ceph_filelock *flocks,
+				       int num_fcntl_locks,
+				       int num_flock_locks);
+extern int ceph_locks_to_pagelist(struct ceph_filelock *flocks,
+				  struct ceph_pagelist *pagelist,
+				  int num_fcntl_locks, int num_flock_locks);
+extern int lock_to_ceph_filelock(struct file_lock *fl, struct ceph_filelock *c);
+
+/* debugfs.c */
+extern int ceph_fs_debugfs_init(struct ceph_fs_client *client);
+extern void ceph_fs_debugfs_cleanup(struct ceph_fs_client *client);
+
+#endif /* _FS_CEPH_SUPER_H */
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
new file mode 100644
index 000000000..cd7ffad40
--- /dev/null
+++ b/fs/ceph/xattr.c
@@ -0,0 +1,1117 @@
+#include <linux/ceph/ceph_debug.h>
+#include <linux/ceph/pagelist.h>
+
+#include "super.h"
+#include "mds_client.h"
+
+#include <linux/ceph/decode.h>
+
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/slab.h>
+
+#define XATTR_CEPH_PREFIX "ceph."
+#define XATTR_CEPH_PREFIX_LEN (sizeof (XATTR_CEPH_PREFIX) - 1)
+
+static int __remove_xattr(struct ceph_inode_info *ci,
+			  struct ceph_inode_xattr *xattr);
+
+/*
+ * List of handlers for synthetic system.* attributes. Other
+ * attributes are handled directly.
+ */
+const struct xattr_handler *ceph_xattr_handlers[] = {
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+	&posix_acl_access_xattr_handler,
+	&posix_acl_default_xattr_handler,
+#endif
+	NULL,
+};
+
+static bool ceph_is_valid_xattr(const char *name)
+{
+	return !strncmp(name, XATTR_CEPH_PREFIX, XATTR_CEPH_PREFIX_LEN) ||
+	       !strncmp(name, XATTR_SECURITY_PREFIX,
+			XATTR_SECURITY_PREFIX_LEN) ||
+	       !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
+	       !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
+	       !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
+}
+
+/*
+ * These define virtual xattrs exposing the recursive directory
+ * statistics and layout metadata.
+ */
+struct ceph_vxattr {
+	char *name;
+	size_t name_size;	/* strlen(name) + 1 (for '\0') */
+	size_t (*getxattr_cb)(struct ceph_inode_info *ci, char *val,
+			      size_t size);
+	bool readonly, hidden;
+	bool (*exists_cb)(struct ceph_inode_info *ci);
+};
+
+/* layouts */
+
+static bool ceph_vxattrcb_layout_exists(struct ceph_inode_info *ci)
+{
+	size_t s;
+	char *p = (char *)&ci->i_layout;
+
+	for (s = 0; s < sizeof(ci->i_layout); s++, p++)
+		if (*p)
+			return true;
+	return false;
+}
+
+static size_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
+				   size_t size)
+{
+	int ret;
+	struct ceph_fs_client *fsc = ceph_sb_to_client(ci->vfs_inode.i_sb);
+	struct ceph_osd_client *osdc = &fsc->client->osdc;
+	s64 pool = ceph_file_layout_pg_pool(ci->i_layout);
+	const char *pool_name;
+	char buf[128];
+
+	dout("ceph_vxattrcb_layout %p\n", &ci->vfs_inode);
+	down_read(&osdc->map_sem);
+	pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, pool);
+	if (pool_name) {
+		size_t len = strlen(pool_name);
+		ret = snprintf(buf, sizeof(buf),
+		"stripe_unit=%lld stripe_count=%lld object_size=%lld pool=",
+		(unsigned long long)ceph_file_layout_su(ci->i_layout),
+		(unsigned long long)ceph_file_layout_stripe_count(ci->i_layout),
+	        (unsigned long long)ceph_file_layout_object_size(ci->i_layout));
+		if (!size) {
+			ret += len;
+		} else if (ret + len > size) {
+			ret = -ERANGE;
+		} else {
+			memcpy(val, buf, ret);
+			memcpy(val + ret, pool_name, len);
+			ret += len;
+		}
+	} else {
+		ret = snprintf(buf, sizeof(buf),
+		"stripe_unit=%lld stripe_count=%lld object_size=%lld pool=%lld",
+		(unsigned long long)ceph_file_layout_su(ci->i_layout),
+		(unsigned long long)ceph_file_layout_stripe_count(ci->i_layout),
+	        (unsigned long long)ceph_file_layout_object_size(ci->i_layout),
+		(unsigned long long)pool);
+		if (size) {
+			if (ret <= size)
+				memcpy(val, buf, ret);
+			else
+				ret = -ERANGE;
+		}
+	}
+	up_read(&osdc->map_sem);
+	return ret;
+}
+
+static size_t ceph_vxattrcb_layout_stripe_unit(struct ceph_inode_info *ci,
+					       char *val, size_t size)
+{
+	return snprintf(val, size, "%lld",
+			(unsigned long long)ceph_file_layout_su(ci->i_layout));
+}
+
+static size_t ceph_vxattrcb_layout_stripe_count(struct ceph_inode_info *ci,
+						char *val, size_t size)
+{
+	return snprintf(val, size, "%lld",
+	       (unsigned long long)ceph_file_layout_stripe_count(ci->i_layout));
+}
+
+static size_t ceph_vxattrcb_layout_object_size(struct ceph_inode_info *ci,
+					       char *val, size_t size)
+{
+	return snprintf(val, size, "%lld",
+	       (unsigned long long)ceph_file_layout_object_size(ci->i_layout));
+}
+
+static size_t ceph_vxattrcb_layout_pool(struct ceph_inode_info *ci,
+					char *val, size_t size)
+{
+	int ret;
+	struct ceph_fs_client *fsc = ceph_sb_to_client(ci->vfs_inode.i_sb);
+	struct ceph_osd_client *osdc = &fsc->client->osdc;
+	s64 pool = ceph_file_layout_pg_pool(ci->i_layout);
+	const char *pool_name;
+
+	down_read(&osdc->map_sem);
+	pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, pool);
+	if (pool_name)
+		ret = snprintf(val, size, "%s", pool_name);
+	else
+		ret = snprintf(val, size, "%lld", (unsigned long long)pool);
+	up_read(&osdc->map_sem);
+	return ret;
+}
+
+/* directories */
+
+static size_t ceph_vxattrcb_dir_entries(struct ceph_inode_info *ci, char *val,
+					size_t size)
+{
+	return snprintf(val, size, "%lld", ci->i_files + ci->i_subdirs);
+}
+
+static size_t ceph_vxattrcb_dir_files(struct ceph_inode_info *ci, char *val,
+				      size_t size)
+{
+	return snprintf(val, size, "%lld", ci->i_files);
+}
+
+static size_t ceph_vxattrcb_dir_subdirs(struct ceph_inode_info *ci, char *val,
+					size_t size)
+{
+	return snprintf(val, size, "%lld", ci->i_subdirs);
+}
+
+static size_t ceph_vxattrcb_dir_rentries(struct ceph_inode_info *ci, char *val,
+					 size_t size)
+{
+	return snprintf(val, size, "%lld", ci->i_rfiles + ci->i_rsubdirs);
+}
+
+static size_t ceph_vxattrcb_dir_rfiles(struct ceph_inode_info *ci, char *val,
+				       size_t size)
+{
+	return snprintf(val, size, "%lld", ci->i_rfiles);
+}
+
+static size_t ceph_vxattrcb_dir_rsubdirs(struct ceph_inode_info *ci, char *val,
+					 size_t size)
+{
+	return snprintf(val, size, "%lld", ci->i_rsubdirs);
+}
+
+static size_t ceph_vxattrcb_dir_rbytes(struct ceph_inode_info *ci, char *val,
+				       size_t size)
+{
+	return snprintf(val, size, "%lld", ci->i_rbytes);
+}
+
+static size_t ceph_vxattrcb_dir_rctime(struct ceph_inode_info *ci, char *val,
+				       size_t size)
+{
+	return snprintf(val, size, "%ld.09%ld", (long)ci->i_rctime.tv_sec,
+			(long)ci->i_rctime.tv_nsec);
+}
+
+
+#define CEPH_XATTR_NAME(_type, _name)	XATTR_CEPH_PREFIX #_type "." #_name
+#define CEPH_XATTR_NAME2(_type, _name, _name2)	\
+	XATTR_CEPH_PREFIX #_type "." #_name "." #_name2
+
+#define XATTR_NAME_CEPH(_type, _name)					\
+	{								\
+		.name = CEPH_XATTR_NAME(_type, _name),			\
+		.name_size = sizeof (CEPH_XATTR_NAME(_type, _name)), \
+		.getxattr_cb = ceph_vxattrcb_ ## _type ## _ ## _name, \
+		.readonly = true,				\
+		.hidden = false,				\
+		.exists_cb = NULL,			\
+	}
+#define XATTR_LAYOUT_FIELD(_type, _name, _field)			\
+	{								\
+		.name = CEPH_XATTR_NAME2(_type, _name, _field),	\
+		.name_size = sizeof (CEPH_XATTR_NAME2(_type, _name, _field)), \
+		.getxattr_cb = ceph_vxattrcb_ ## _name ## _ ## _field, \
+		.readonly = false,				\
+		.hidden = true,			\
+		.exists_cb = ceph_vxattrcb_layout_exists,	\
+	}
+
+static struct ceph_vxattr ceph_dir_vxattrs[] = {
+	{
+		.name = "ceph.dir.layout",
+		.name_size = sizeof("ceph.dir.layout"),
+		.getxattr_cb = ceph_vxattrcb_layout,
+		.readonly = false,
+		.hidden = true,
+		.exists_cb = ceph_vxattrcb_layout_exists,
+	},
+	XATTR_LAYOUT_FIELD(dir, layout, stripe_unit),
+	XATTR_LAYOUT_FIELD(dir, layout, stripe_count),
+	XATTR_LAYOUT_FIELD(dir, layout, object_size),
+	XATTR_LAYOUT_FIELD(dir, layout, pool),
+	XATTR_NAME_CEPH(dir, entries),
+	XATTR_NAME_CEPH(dir, files),
+	XATTR_NAME_CEPH(dir, subdirs),
+	XATTR_NAME_CEPH(dir, rentries),
+	XATTR_NAME_CEPH(dir, rfiles),
+	XATTR_NAME_CEPH(dir, rsubdirs),
+	XATTR_NAME_CEPH(dir, rbytes),
+	XATTR_NAME_CEPH(dir, rctime),
+	{ .name = NULL, 0 }	/* Required table terminator */
+};
+static size_t ceph_dir_vxattrs_name_size;	/* total size of all names */
+
+/* files */
+
+static struct ceph_vxattr ceph_file_vxattrs[] = {
+	{
+		.name = "ceph.file.layout",
+		.name_size = sizeof("ceph.file.layout"),
+		.getxattr_cb = ceph_vxattrcb_layout,
+		.readonly = false,
+		.hidden = true,
+		.exists_cb = ceph_vxattrcb_layout_exists,
+	},
+	XATTR_LAYOUT_FIELD(file, layout, stripe_unit),
+	XATTR_LAYOUT_FIELD(file, layout, stripe_count),
+	XATTR_LAYOUT_FIELD(file, layout, object_size),
+	XATTR_LAYOUT_FIELD(file, layout, pool),
+	{ .name = NULL, 0 }	/* Required table terminator */
+};
+static size_t ceph_file_vxattrs_name_size;	/* total size of all names */
+
+static struct ceph_vxattr *ceph_inode_vxattrs(struct inode *inode)
+{
+	if (S_ISDIR(inode->i_mode))
+		return ceph_dir_vxattrs;
+	else if (S_ISREG(inode->i_mode))
+		return ceph_file_vxattrs;
+	return NULL;
+}
+
+static size_t ceph_vxattrs_name_size(struct ceph_vxattr *vxattrs)
+{
+	if (vxattrs == ceph_dir_vxattrs)
+		return ceph_dir_vxattrs_name_size;
+	if (vxattrs == ceph_file_vxattrs)
+		return ceph_file_vxattrs_name_size;
+	BUG_ON(vxattrs);
+	return 0;
+}
+
+/*
+ * Compute the aggregate size (including terminating '\0') of all
+ * virtual extended attribute names in the given vxattr table.
+ */
+static size_t __init vxattrs_name_size(struct ceph_vxattr *vxattrs)
+{
+	struct ceph_vxattr *vxattr;
+	size_t size = 0;
+
+	for (vxattr = vxattrs; vxattr->name; vxattr++)
+		if (!vxattr->hidden)
+			size += vxattr->name_size;
+
+	return size;
+}
+
+/* Routines called at initialization and exit time */
+
+void __init ceph_xattr_init(void)
+{
+	ceph_dir_vxattrs_name_size = vxattrs_name_size(ceph_dir_vxattrs);
+	ceph_file_vxattrs_name_size = vxattrs_name_size(ceph_file_vxattrs);
+}
+
+void ceph_xattr_exit(void)
+{
+	ceph_dir_vxattrs_name_size = 0;
+	ceph_file_vxattrs_name_size = 0;
+}
+
+static struct ceph_vxattr *ceph_match_vxattr(struct inode *inode,
+						const char *name)
+{
+	struct ceph_vxattr *vxattr = ceph_inode_vxattrs(inode);
+
+	if (vxattr) {
+		while (vxattr->name) {
+			if (!strcmp(vxattr->name, name))
+				return vxattr;
+			vxattr++;
+		}
+	}
+
+	return NULL;
+}
+
+static int __set_xattr(struct ceph_inode_info *ci,
+			   const char *name, int name_len,
+			   const char *val, int val_len,
+			   int flags, int update_xattr,
+			   struct ceph_inode_xattr **newxattr)
+{
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+	struct ceph_inode_xattr *xattr = NULL;
+	int c;
+	int new = 0;
+
+	p = &ci->i_xattrs.index.rb_node;
+	while (*p) {
+		parent = *p;
+		xattr = rb_entry(parent, struct ceph_inode_xattr, node);
+		c = strncmp(name, xattr->name, min(name_len, xattr->name_len));
+		if (c < 0)
+			p = &(*p)->rb_left;
+		else if (c > 0)
+			p = &(*p)->rb_right;
+		else {
+			if (name_len == xattr->name_len)
+				break;
+			else if (name_len < xattr->name_len)
+				p = &(*p)->rb_left;
+			else
+				p = &(*p)->rb_right;
+		}
+		xattr = NULL;
+	}
+
+	if (update_xattr) {
+		int err = 0;
+		if (xattr && (flags & XATTR_CREATE))
+			err = -EEXIST;
+		else if (!xattr && (flags & XATTR_REPLACE))
+			err = -ENODATA;
+		if (err) {
+			kfree(name);
+			kfree(val);
+			return err;
+		}
+		if (update_xattr < 0) {
+			if (xattr)
+				__remove_xattr(ci, xattr);
+			kfree(name);
+			return 0;
+		}
+	}
+
+	if (!xattr) {
+		new = 1;
+		xattr = *newxattr;
+		xattr->name = name;
+		xattr->name_len = name_len;
+		xattr->should_free_name = update_xattr;
+
+		ci->i_xattrs.count++;
+		dout("__set_xattr count=%d\n", ci->i_xattrs.count);
+	} else {
+		kfree(*newxattr);
+		*newxattr = NULL;
+		if (xattr->should_free_val)
+			kfree((void *)xattr->val);
+
+		if (update_xattr) {
+			kfree((void *)name);
+			name = xattr->name;
+		}
+		ci->i_xattrs.names_size -= xattr->name_len;
+		ci->i_xattrs.vals_size -= xattr->val_len;
+	}
+	ci->i_xattrs.names_size += name_len;
+	ci->i_xattrs.vals_size += val_len;
+	if (val)
+		xattr->val = val;
+	else
+		xattr->val = "";
+
+	xattr->val_len = val_len;
+	xattr->dirty = update_xattr;
+	xattr->should_free_val = (val && update_xattr);
+
+	if (new) {
+		rb_link_node(&xattr->node, parent, p);
+		rb_insert_color(&xattr->node, &ci->i_xattrs.index);
+		dout("__set_xattr_val p=%p\n", p);
+	}
+
+	dout("__set_xattr_val added %llx.%llx xattr %p %s=%.*s\n",
+	     ceph_vinop(&ci->vfs_inode), xattr, name, val_len, val);
+
+	return 0;
+}
+
+static struct ceph_inode_xattr *__get_xattr(struct ceph_inode_info *ci,
+			   const char *name)
+{
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+	struct ceph_inode_xattr *xattr = NULL;
+	int name_len = strlen(name);
+	int c;
+
+	p = &ci->i_xattrs.index.rb_node;
+	while (*p) {
+		parent = *p;
+		xattr = rb_entry(parent, struct ceph_inode_xattr, node);
+		c = strncmp(name, xattr->name, xattr->name_len);
+		if (c == 0 && name_len > xattr->name_len)
+			c = 1;
+		if (c < 0)
+			p = &(*p)->rb_left;
+		else if (c > 0)
+			p = &(*p)->rb_right;
+		else {
+			dout("__get_xattr %s: found %.*s\n", name,
+			     xattr->val_len, xattr->val);
+			return xattr;
+		}
+	}
+
+	dout("__get_xattr %s: not found\n", name);
+
+	return NULL;
+}
+
+static void __free_xattr(struct ceph_inode_xattr *xattr)
+{
+	BUG_ON(!xattr);
+
+	if (xattr->should_free_name)
+		kfree((void *)xattr->name);
+	if (xattr->should_free_val)
+		kfree((void *)xattr->val);
+
+	kfree(xattr);
+}
+
+static int __remove_xattr(struct ceph_inode_info *ci,
+			  struct ceph_inode_xattr *xattr)
+{
+	if (!xattr)
+		return -ENODATA;
+
+	rb_erase(&xattr->node, &ci->i_xattrs.index);
+
+	if (xattr->should_free_name)
+		kfree((void *)xattr->name);
+	if (xattr->should_free_val)
+		kfree((void *)xattr->val);
+
+	ci->i_xattrs.names_size -= xattr->name_len;
+	ci->i_xattrs.vals_size -= xattr->val_len;
+	ci->i_xattrs.count--;
+	kfree(xattr);
+
+	return 0;
+}
+
+static int __remove_xattr_by_name(struct ceph_inode_info *ci,
+			   const char *name)
+{
+	struct rb_node **p;
+	struct ceph_inode_xattr *xattr;
+	int err;
+
+	p = &ci->i_xattrs.index.rb_node;
+	xattr = __get_xattr(ci, name);
+	err = __remove_xattr(ci, xattr);
+	return err;
+}
+
+static char *__copy_xattr_names(struct ceph_inode_info *ci,
+				char *dest)
+{
+	struct rb_node *p;
+	struct ceph_inode_xattr *xattr = NULL;
+
+	p = rb_first(&ci->i_xattrs.index);
+	dout("__copy_xattr_names count=%d\n", ci->i_xattrs.count);
+
+	while (p) {
+		xattr = rb_entry(p, struct ceph_inode_xattr, node);
+		memcpy(dest, xattr->name, xattr->name_len);
+		dest[xattr->name_len] = '\0';
+
+		dout("dest=%s %p (%s) (%d/%d)\n", dest, xattr, xattr->name,
+		     xattr->name_len, ci->i_xattrs.names_size);
+
+		dest += xattr->name_len + 1;
+		p = rb_next(p);
+	}
+
+	return dest;
+}
+
+void __ceph_destroy_xattrs(struct ceph_inode_info *ci)
+{
+	struct rb_node *p, *tmp;
+	struct ceph_inode_xattr *xattr = NULL;
+
+	p = rb_first(&ci->i_xattrs.index);
+
+	dout("__ceph_destroy_xattrs p=%p\n", p);
+
+	while (p) {
+		xattr = rb_entry(p, struct ceph_inode_xattr, node);
+		tmp = p;
+		p = rb_next(tmp);
+		dout("__ceph_destroy_xattrs next p=%p (%.*s)\n", p,
+		     xattr->name_len, xattr->name);
+		rb_erase(tmp, &ci->i_xattrs.index);
+
+		__free_xattr(xattr);
+	}
+
+	ci->i_xattrs.names_size = 0;
+	ci->i_xattrs.vals_size = 0;
+	ci->i_xattrs.index_version = 0;
+	ci->i_xattrs.count = 0;
+	ci->i_xattrs.index = RB_ROOT;
+}
+
+static int __build_xattrs(struct inode *inode)
+	__releases(ci->i_ceph_lock)
+	__acquires(ci->i_ceph_lock)
+{
+	u32 namelen;
+	u32 numattr = 0;
+	void *p, *end;
+	u32 len;
+	const char *name, *val;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int xattr_version;
+	struct ceph_inode_xattr **xattrs = NULL;
+	int err = 0;
+	int i;
+
+	dout("__build_xattrs() len=%d\n",
+	     ci->i_xattrs.blob ? (int)ci->i_xattrs.blob->vec.iov_len : 0);
+
+	if (ci->i_xattrs.index_version >= ci->i_xattrs.version)
+		return 0; /* already built */
+
+	__ceph_destroy_xattrs(ci);
+
+start:
+	/* updated internal xattr rb tree */
+	if (ci->i_xattrs.blob && ci->i_xattrs.blob->vec.iov_len > 4) {
+		p = ci->i_xattrs.blob->vec.iov_base;
+		end = p + ci->i_xattrs.blob->vec.iov_len;
+		ceph_decode_32_safe(&p, end, numattr, bad);
+		xattr_version = ci->i_xattrs.version;
+		spin_unlock(&ci->i_ceph_lock);
+
+		xattrs = kcalloc(numattr, sizeof(struct ceph_inode_xattr *),
+				 GFP_NOFS);
+		err = -ENOMEM;
+		if (!xattrs)
+			goto bad_lock;
+
+		for (i = 0; i < numattr; i++) {
+			xattrs[i] = kmalloc(sizeof(struct ceph_inode_xattr),
+					    GFP_NOFS);
+			if (!xattrs[i])
+				goto bad_lock;
+		}
+
+		spin_lock(&ci->i_ceph_lock);
+		if (ci->i_xattrs.version != xattr_version) {
+			/* lost a race, retry */
+			for (i = 0; i < numattr; i++)
+				kfree(xattrs[i]);
+			kfree(xattrs);
+			xattrs = NULL;
+			goto start;
+		}
+		err = -EIO;
+		while (numattr--) {
+			ceph_decode_32_safe(&p, end, len, bad);
+			namelen = len;
+			name = p;
+			p += len;
+			ceph_decode_32_safe(&p, end, len, bad);
+			val = p;
+			p += len;
+
+			err = __set_xattr(ci, name, namelen, val, len,
+					  0, 0, &xattrs[numattr]);
+
+			if (err < 0)
+				goto bad;
+		}
+		kfree(xattrs);
+	}
+	ci->i_xattrs.index_version = ci->i_xattrs.version;
+	ci->i_xattrs.dirty = false;
+
+	return err;
+bad_lock:
+	spin_lock(&ci->i_ceph_lock);
+bad:
+	if (xattrs) {
+		for (i = 0; i < numattr; i++)
+			kfree(xattrs[i]);
+		kfree(xattrs);
+	}
+	ci->i_xattrs.names_size = 0;
+	return err;
+}
+
+static int __get_required_blob_size(struct ceph_inode_info *ci, int name_size,
+				    int val_size)
+{
+	/*
+	 * 4 bytes for the length, and additional 4 bytes per each xattr name,
+	 * 4 bytes per each value
+	 */
+	int size = 4 + ci->i_xattrs.count*(4 + 4) +
+			     ci->i_xattrs.names_size +
+			     ci->i_xattrs.vals_size;
+	dout("__get_required_blob_size c=%d names.size=%d vals.size=%d\n",
+	     ci->i_xattrs.count, ci->i_xattrs.names_size,
+	     ci->i_xattrs.vals_size);
+
+	if (name_size)
+		size += 4 + 4 + name_size + val_size;
+
+	return size;
+}
+
+/*
+ * If there are dirty xattrs, reencode xattrs into the prealloc_blob
+ * and swap into place.
+ */
+void __ceph_build_xattrs_blob(struct ceph_inode_info *ci)
+{
+	struct rb_node *p;
+	struct ceph_inode_xattr *xattr = NULL;
+	void *dest;
+
+	dout("__build_xattrs_blob %p\n", &ci->vfs_inode);
+	if (ci->i_xattrs.dirty) {
+		int need = __get_required_blob_size(ci, 0, 0);
+
+		BUG_ON(need > ci->i_xattrs.prealloc_blob->alloc_len);
+
+		p = rb_first(&ci->i_xattrs.index);
+		dest = ci->i_xattrs.prealloc_blob->vec.iov_base;
+
+		ceph_encode_32(&dest, ci->i_xattrs.count);
+		while (p) {
+			xattr = rb_entry(p, struct ceph_inode_xattr, node);
+
+			ceph_encode_32(&dest, xattr->name_len);
+			memcpy(dest, xattr->name, xattr->name_len);
+			dest += xattr->name_len;
+			ceph_encode_32(&dest, xattr->val_len);
+			memcpy(dest, xattr->val, xattr->val_len);
+			dest += xattr->val_len;
+
+			p = rb_next(p);
+		}
+
+		/* adjust buffer len; it may be larger than we need */
+		ci->i_xattrs.prealloc_blob->vec.iov_len =
+			dest - ci->i_xattrs.prealloc_blob->vec.iov_base;
+
+		if (ci->i_xattrs.blob)
+			ceph_buffer_put(ci->i_xattrs.blob);
+		ci->i_xattrs.blob = ci->i_xattrs.prealloc_blob;
+		ci->i_xattrs.prealloc_blob = NULL;
+		ci->i_xattrs.dirty = false;
+		ci->i_xattrs.version++;
+	}
+}
+
+ssize_t __ceph_getxattr(struct inode *inode, const char *name, void *value,
+		      size_t size)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int err;
+	struct ceph_inode_xattr *xattr;
+	struct ceph_vxattr *vxattr = NULL;
+
+	if (!ceph_is_valid_xattr(name))
+		return -ENODATA;
+
+	/* let's see if a virtual xattr was requested */
+	vxattr = ceph_match_vxattr(inode, name);
+	if (vxattr && !(vxattr->exists_cb && !vxattr->exists_cb(ci))) {
+		err = vxattr->getxattr_cb(ci, value, size);
+		return err;
+	}
+
+	spin_lock(&ci->i_ceph_lock);
+	dout("getxattr %p ver=%lld index_ver=%lld\n", inode,
+	     ci->i_xattrs.version, ci->i_xattrs.index_version);
+
+	if (ci->i_xattrs.version == 0 ||
+	    !__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1)) {
+		spin_unlock(&ci->i_ceph_lock);
+		/* get xattrs from mds (if we don't already have them) */
+		err = ceph_do_getattr(inode, CEPH_STAT_CAP_XATTR, true);
+		if (err)
+			return err;
+		spin_lock(&ci->i_ceph_lock);
+	}
+
+	err = __build_xattrs(inode);
+	if (err < 0)
+		goto out;
+
+	err = -ENODATA;  /* == ENOATTR */
+	xattr = __get_xattr(ci, name);
+	if (!xattr)
+		goto out;
+
+	err = -ERANGE;
+	if (size && size < xattr->val_len)
+		goto out;
+
+	err = xattr->val_len;
+	if (size == 0)
+		goto out;
+
+	memcpy(value, xattr->val, xattr->val_len);
+
+out:
+	spin_unlock(&ci->i_ceph_lock);
+	return err;
+}
+
+ssize_t ceph_getxattr(struct dentry *dentry, const char *name, void *value,
+		      size_t size)
+{
+	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return generic_getxattr(dentry, name, value, size);
+
+	return __ceph_getxattr(d_inode(dentry), name, value, size);
+}
+
+ssize_t ceph_listxattr(struct dentry *dentry, char *names, size_t size)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_vxattr *vxattrs = ceph_inode_vxattrs(inode);
+	u32 vir_namelen = 0;
+	u32 namelen;
+	int err;
+	u32 len;
+	int i;
+
+	spin_lock(&ci->i_ceph_lock);
+	dout("listxattr %p ver=%lld index_ver=%lld\n", inode,
+	     ci->i_xattrs.version, ci->i_xattrs.index_version);
+
+	if (ci->i_xattrs.version == 0 ||
+	    !__ceph_caps_issued_mask(ci, CEPH_CAP_XATTR_SHARED, 1)) {
+		spin_unlock(&ci->i_ceph_lock);
+		err = ceph_do_getattr(inode, CEPH_STAT_CAP_XATTR, true);
+		if (err)
+			return err;
+		spin_lock(&ci->i_ceph_lock);
+	}
+
+	err = __build_xattrs(inode);
+	if (err < 0)
+		goto out;
+	/*
+	 * Start with virtual dir xattr names (if any) (including
+	 * terminating '\0' characters for each).
+	 */
+	vir_namelen = ceph_vxattrs_name_size(vxattrs);
+
+	/* adding 1 byte per each variable due to the null termination */
+	namelen = ci->i_xattrs.names_size + ci->i_xattrs.count;
+	err = -ERANGE;
+	if (size && vir_namelen + namelen > size)
+		goto out;
+
+	err = namelen + vir_namelen;
+	if (size == 0)
+		goto out;
+
+	names = __copy_xattr_names(ci, names);
+
+	/* virtual xattr names, too */
+	err = namelen;
+	if (vxattrs) {
+		for (i = 0; vxattrs[i].name; i++) {
+			if (!vxattrs[i].hidden &&
+			    !(vxattrs[i].exists_cb &&
+			      !vxattrs[i].exists_cb(ci))) {
+				len = sprintf(names, "%s", vxattrs[i].name);
+				names += len + 1;
+				err += len + 1;
+			}
+		}
+	}
+
+out:
+	spin_unlock(&ci->i_ceph_lock);
+	return err;
+}
+
+static int ceph_sync_setxattr(struct dentry *dentry, const char *name,
+			      const char *value, size_t size, int flags)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
+	struct inode *inode = d_inode(dentry);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_mds_request *req;
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_pagelist *pagelist = NULL;
+	int err;
+
+	if (size > 0) {
+		/* copy value into pagelist */
+		pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
+		if (!pagelist)
+			return -ENOMEM;
+
+		ceph_pagelist_init(pagelist);
+		err = ceph_pagelist_append(pagelist, value, size);
+		if (err)
+			goto out;
+	} else if (!value) {
+		flags |= CEPH_XATTR_REMOVE;
+	}
+
+	dout("setxattr value=%.*s\n", (int)size, value);
+
+	/* do request */
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETXATTR,
+				       USE_AUTH_MDS);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto out;
+	}
+
+	req->r_args.setxattr.flags = cpu_to_le32(flags);
+	req->r_path2 = kstrdup(name, GFP_NOFS);
+	if (!req->r_path2) {
+		ceph_mdsc_put_request(req);
+		err = -ENOMEM;
+		goto out;
+	}
+
+	req->r_pagelist = pagelist;
+	pagelist = NULL;
+
+	req->r_inode = inode;
+	ihold(inode);
+	req->r_num_caps = 1;
+	req->r_inode_drop = CEPH_CAP_XATTR_SHARED;
+
+	dout("xattr.ver (before): %lld\n", ci->i_xattrs.version);
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	ceph_mdsc_put_request(req);
+	dout("xattr.ver (after): %lld\n", ci->i_xattrs.version);
+
+out:
+	if (pagelist)
+		ceph_pagelist_release(pagelist);
+	return err;
+}
+
+int __ceph_setxattr(struct dentry *dentry, const char *name,
+			const void *value, size_t size, int flags)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ceph_vxattr *vxattr;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int issued;
+	int err;
+	int dirty = 0;
+	int name_len = strlen(name);
+	int val_len = size;
+	char *newname = NULL;
+	char *newval = NULL;
+	struct ceph_inode_xattr *xattr = NULL;
+	int required_blob_size;
+
+	if (!ceph_is_valid_xattr(name))
+		return -EOPNOTSUPP;
+
+	vxattr = ceph_match_vxattr(inode, name);
+	if (vxattr && vxattr->readonly)
+		return -EOPNOTSUPP;
+
+	/* pass any unhandled ceph.* xattrs through to the MDS */
+	if (!strncmp(name, XATTR_CEPH_PREFIX, XATTR_CEPH_PREFIX_LEN))
+		goto do_sync_unlocked;
+
+	/* preallocate memory for xattr name, value, index node */
+	err = -ENOMEM;
+	newname = kmemdup(name, name_len + 1, GFP_NOFS);
+	if (!newname)
+		goto out;
+
+	if (val_len) {
+		newval = kmemdup(value, val_len, GFP_NOFS);
+		if (!newval)
+			goto out;
+	}
+
+	xattr = kmalloc(sizeof(struct ceph_inode_xattr), GFP_NOFS);
+	if (!xattr)
+		goto out;
+
+	spin_lock(&ci->i_ceph_lock);
+retry:
+	issued = __ceph_caps_issued(ci, NULL);
+	dout("setxattr %p issued %s\n", inode, ceph_cap_string(issued));
+	if (ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL))
+		goto do_sync;
+	__build_xattrs(inode);
+
+	required_blob_size = __get_required_blob_size(ci, name_len, val_len);
+
+	if (!ci->i_xattrs.prealloc_blob ||
+	    required_blob_size > ci->i_xattrs.prealloc_blob->alloc_len) {
+		struct ceph_buffer *blob;
+
+		spin_unlock(&ci->i_ceph_lock);
+		dout(" preaallocating new blob size=%d\n", required_blob_size);
+		blob = ceph_buffer_new(required_blob_size, GFP_NOFS);
+		if (!blob)
+			goto out;
+		spin_lock(&ci->i_ceph_lock);
+		if (ci->i_xattrs.prealloc_blob)
+			ceph_buffer_put(ci->i_xattrs.prealloc_blob);
+		ci->i_xattrs.prealloc_blob = blob;
+		goto retry;
+	}
+
+	err = __set_xattr(ci, newname, name_len, newval, val_len,
+			  flags, value ? 1 : -1, &xattr);
+
+	if (!err) {
+		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_XATTR_EXCL);
+		ci->i_xattrs.dirty = true;
+		inode->i_ctime = CURRENT_TIME;
+	}
+
+	spin_unlock(&ci->i_ceph_lock);
+	if (dirty)
+		__mark_inode_dirty(inode, dirty);
+	return err;
+
+do_sync:
+	spin_unlock(&ci->i_ceph_lock);
+do_sync_unlocked:
+	err = ceph_sync_setxattr(dentry, name, value, size, flags);
+out:
+	kfree(newname);
+	kfree(newval);
+	kfree(xattr);
+	return err;
+}
+
+int ceph_setxattr(struct dentry *dentry, const char *name,
+		  const void *value, size_t size, int flags)
+{
+	if (ceph_snap(d_inode(dentry)) != CEPH_NOSNAP)
+		return -EROFS;
+
+	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return generic_setxattr(dentry, name, value, size, flags);
+
+	if (size == 0)
+		value = "";  /* empty EA, do not remove */
+
+	return __ceph_setxattr(dentry, name, value, size, flags);
+}
+
+static int ceph_send_removexattr(struct dentry *dentry, const char *name)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct inode *inode = d_inode(dentry);
+	struct ceph_mds_request *req;
+	int err;
+
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_RMXATTR,
+				       USE_AUTH_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	req->r_path2 = kstrdup(name, GFP_NOFS);
+	if (!req->r_path2)
+		return -ENOMEM;
+
+	req->r_inode = inode;
+	ihold(inode);
+	req->r_num_caps = 1;
+	req->r_inode_drop = CEPH_CAP_XATTR_SHARED;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	ceph_mdsc_put_request(req);
+	return err;
+}
+
+int __ceph_removexattr(struct dentry *dentry, const char *name)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ceph_vxattr *vxattr;
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int issued;
+	int err;
+	int required_blob_size;
+	int dirty;
+
+	if (!ceph_is_valid_xattr(name))
+		return -EOPNOTSUPP;
+
+	vxattr = ceph_match_vxattr(inode, name);
+	if (vxattr && vxattr->readonly)
+		return -EOPNOTSUPP;
+
+	/* pass any unhandled ceph.* xattrs through to the MDS */
+	if (!strncmp(name, XATTR_CEPH_PREFIX, XATTR_CEPH_PREFIX_LEN))
+		goto do_sync_unlocked;
+
+	err = -ENOMEM;
+	spin_lock(&ci->i_ceph_lock);
+retry:
+	issued = __ceph_caps_issued(ci, NULL);
+	dout("removexattr %p issued %s\n", inode, ceph_cap_string(issued));
+
+	if (ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL))
+		goto do_sync;
+	__build_xattrs(inode);
+
+	required_blob_size = __get_required_blob_size(ci, 0, 0);
+
+	if (!ci->i_xattrs.prealloc_blob ||
+	    required_blob_size > ci->i_xattrs.prealloc_blob->alloc_len) {
+		struct ceph_buffer *blob;
+
+		spin_unlock(&ci->i_ceph_lock);
+		dout(" preaallocating new blob size=%d\n", required_blob_size);
+		blob = ceph_buffer_new(required_blob_size, GFP_NOFS);
+		if (!blob)
+			goto out;
+		spin_lock(&ci->i_ceph_lock);
+		if (ci->i_xattrs.prealloc_blob)
+			ceph_buffer_put(ci->i_xattrs.prealloc_blob);
+		ci->i_xattrs.prealloc_blob = blob;
+		goto retry;
+	}
+
+	err = __remove_xattr_by_name(ceph_inode(inode), name);
+
+	dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_XATTR_EXCL);
+	ci->i_xattrs.dirty = true;
+	inode->i_ctime = CURRENT_TIME;
+	spin_unlock(&ci->i_ceph_lock);
+	if (dirty)
+		__mark_inode_dirty(inode, dirty);
+	return err;
+do_sync:
+	spin_unlock(&ci->i_ceph_lock);
+do_sync_unlocked:
+	err = ceph_send_removexattr(dentry, name);
+out:
+	return err;
+}
+
+int ceph_removexattr(struct dentry *dentry, const char *name)
+{
+	if (ceph_snap(d_inode(dentry)) != CEPH_NOSNAP)
+		return -EROFS;
+
+	if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return generic_removexattr(dentry, name);
+
+	return __ceph_removexattr(dentry, name);
+}