Initial import

1 files changed, 1599 insertions, 0 deletions

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;
+}