Initial import

1 files changed, 1330 insertions, 0 deletions

diff --git a/fs/ext3/xattr.c b/fs/ext3/xattr.c
new file mode 100644
index 000000000..7cf36501c
--- /dev/null
+++ b/fs/ext3/xattr.c
@@ -0,0 +1,1330 @@
+/*
+ * linux/fs/ext3/xattr.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ *
+ * Fix by Harrison Xing <harrison@mountainviewdata.com>.
+ * Ext3 code with a lot of help from Eric Jarman <ejarman@acm.org>.
+ * Extended attributes for symlinks and special files added per
+ *  suggestion of Luka Renko <luka.renko@hermes.si>.
+ * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
+ *  Red Hat Inc.
+ * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
+ *  and Andreas Gruenbacher <agruen@suse.de>.
+ */
+
+/*
+ * Extended attributes are stored directly in inodes (on file systems with
+ * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
+ * field contains the block number if an inode uses an additional block. All
+ * attributes must fit in the inode and one additional block. Blocks that
+ * contain the identical set of attributes may be shared among several inodes.
+ * Identical blocks are detected by keeping a cache of blocks that have
+ * recently been accessed.
+ *
+ * The attributes in inodes and on blocks have a different header; the entries
+ * are stored in the same format:
+ *
+ *   +------------------+
+ *   | header           |
+ *   | entry 1          | |
+ *   | entry 2          | | growing downwards
+ *   | entry 3          | v
+ *   | four null bytes  |
+ *   | . . .            |
+ *   | value 1          | ^
+ *   | value 3          | | growing upwards
+ *   | value 2          | |
+ *   +------------------+
+ *
+ * The header is followed by multiple entry descriptors. In disk blocks, the
+ * entry descriptors are kept sorted. In inodes, they are unsorted. The
+ * attribute values are aligned to the end of the block in no specific order.
+ *
+ * Locking strategy
+ * ----------------
+ * EXT3_I(inode)->i_file_acl is protected by EXT3_I(inode)->xattr_sem.
+ * EA blocks are only changed if they are exclusive to an inode, so
+ * holding xattr_sem also means that nothing but the EA block's reference
+ * count can change. Multiple writers to the same block are synchronized
+ * by the buffer lock.
+ */
+
+#include "ext3.h"
+#include <linux/mbcache.h>
+#include <linux/quotaops.h>
+#include "xattr.h"
+#include "acl.h"
+
+#define BHDR(bh) ((struct ext3_xattr_header *)((bh)->b_data))
+#define ENTRY(ptr) ((struct ext3_xattr_entry *)(ptr))
+#define BFIRST(bh) ENTRY(BHDR(bh)+1)
+#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#define IHDR(inode, raw_inode) \
+	((struct ext3_xattr_ibody_header *) \
+		((void *)raw_inode + \
+		 EXT3_GOOD_OLD_INODE_SIZE + \
+		 EXT3_I(inode)->i_extra_isize))
+#define IFIRST(hdr) ((struct ext3_xattr_entry *)((hdr)+1))
+
+#ifdef EXT3_XATTR_DEBUG
+# define ea_idebug(inode, f...) do { \
+		printk(KERN_DEBUG "inode %s:%lu: ", \
+			inode->i_sb->s_id, inode->i_ino); \
+		printk(f); \
+		printk("\n"); \
+	} while (0)
+# define ea_bdebug(bh, f...) do { \
+		char b[BDEVNAME_SIZE]; \
+		printk(KERN_DEBUG "block %s:%lu: ", \
+			bdevname(bh->b_bdev, b), \
+			(unsigned long) bh->b_blocknr); \
+		printk(f); \
+		printk("\n"); \
+	} while (0)
+#else
+# define ea_idebug(f...)
+# define ea_bdebug(f...)
+#endif
+
+static void ext3_xattr_cache_insert(struct buffer_head *);
+static struct buffer_head *ext3_xattr_cache_find(struct inode *,
+						 struct ext3_xattr_header *,
+						 struct mb_cache_entry **);
+static void ext3_xattr_rehash(struct ext3_xattr_header *,
+			      struct ext3_xattr_entry *);
+static int ext3_xattr_list(struct dentry *dentry, char *buffer,
+			   size_t buffer_size);
+
+static struct mb_cache *ext3_xattr_cache;
+
+static const struct xattr_handler *ext3_xattr_handler_map[] = {
+	[EXT3_XATTR_INDEX_USER]		     = &ext3_xattr_user_handler,
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	[EXT3_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
+	[EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
+#endif
+	[EXT3_XATTR_INDEX_TRUSTED]	     = &ext3_xattr_trusted_handler,
+#ifdef CONFIG_EXT3_FS_SECURITY
+	[EXT3_XATTR_INDEX_SECURITY]	     = &ext3_xattr_security_handler,
+#endif
+};
+
+const struct xattr_handler *ext3_xattr_handlers[] = {
+	&ext3_xattr_user_handler,
+	&ext3_xattr_trusted_handler,
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	&posix_acl_access_xattr_handler,
+	&posix_acl_default_xattr_handler,
+#endif
+#ifdef CONFIG_EXT3_FS_SECURITY
+	&ext3_xattr_security_handler,
+#endif
+	NULL
+};
+
+static inline const struct xattr_handler *
+ext3_xattr_handler(int name_index)
+{
+	const struct xattr_handler *handler = NULL;
+
+	if (name_index > 0 && name_index < ARRAY_SIZE(ext3_xattr_handler_map))
+		handler = ext3_xattr_handler_map[name_index];
+	return handler;
+}
+
+/*
+ * Inode operation listxattr()
+ *
+ * d_inode(dentry)->i_mutex: don't care
+ */
+ssize_t
+ext3_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+	return ext3_xattr_list(dentry, buffer, size);
+}
+
+static int
+ext3_xattr_check_names(struct ext3_xattr_entry *entry, void *end)
+{
+	while (!IS_LAST_ENTRY(entry)) {
+		struct ext3_xattr_entry *next = EXT3_XATTR_NEXT(entry);
+		if ((void *)next >= end)
+			return -EIO;
+		entry = next;
+	}
+	return 0;
+}
+
+static inline int
+ext3_xattr_check_block(struct buffer_head *bh)
+{
+	int error;
+
+	if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
+	    BHDR(bh)->h_blocks != cpu_to_le32(1))
+		return -EIO;
+	error = ext3_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
+	return error;
+}
+
+static inline int
+ext3_xattr_check_entry(struct ext3_xattr_entry *entry, size_t size)
+{
+	size_t value_size = le32_to_cpu(entry->e_value_size);
+
+	if (entry->e_value_block != 0 || value_size > size ||
+	    le16_to_cpu(entry->e_value_offs) + value_size > size)
+		return -EIO;
+	return 0;
+}
+
+static int
+ext3_xattr_find_entry(struct ext3_xattr_entry **pentry, int name_index,
+		      const char *name, size_t size, int sorted)
+{
+	struct ext3_xattr_entry *entry;
+	size_t name_len;
+	int cmp = 1;
+
+	if (name == NULL)
+		return -EINVAL;
+	name_len = strlen(name);
+	entry = *pentry;
+	for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
+		cmp = name_index - entry->e_name_index;
+		if (!cmp)
+			cmp = name_len - entry->e_name_len;
+		if (!cmp)
+			cmp = memcmp(name, entry->e_name, name_len);
+		if (cmp <= 0 && (sorted || cmp == 0))
+			break;
+	}
+	*pentry = entry;
+	if (!cmp && ext3_xattr_check_entry(entry, size))
+			return -EIO;
+	return cmp ? -ENODATA : 0;
+}
+
+static int
+ext3_xattr_block_get(struct inode *inode, int name_index, const char *name,
+		     void *buffer, size_t buffer_size)
+{
+	struct buffer_head *bh = NULL;
+	struct ext3_xattr_entry *entry;
+	size_t size;
+	int error;
+
+	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
+		  name_index, name, buffer, (long)buffer_size);
+
+	error = -ENODATA;
+	if (!EXT3_I(inode)->i_file_acl)
+		goto cleanup;
+	ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
+	bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
+	if (!bh)
+		goto cleanup;
+	ea_bdebug(bh, "b_count=%d, refcount=%d",
+		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
+	if (ext3_xattr_check_block(bh)) {
+bad_block:	ext3_error(inode->i_sb, __func__,
+			   "inode %lu: bad block "E3FSBLK, inode->i_ino,
+			   EXT3_I(inode)->i_file_acl);
+		error = -EIO;
+		goto cleanup;
+	}
+	ext3_xattr_cache_insert(bh);
+	entry = BFIRST(bh);
+	error = ext3_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
+	if (error == -EIO)
+		goto bad_block;
+	if (error)
+		goto cleanup;
+	size = le32_to_cpu(entry->e_value_size);
+	if (buffer) {
+		error = -ERANGE;
+		if (size > buffer_size)
+			goto cleanup;
+		memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
+		       size);
+	}
+	error = size;
+
+cleanup:
+	brelse(bh);
+	return error;
+}
+
+static int
+ext3_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
+		     void *buffer, size_t buffer_size)
+{
+	struct ext3_xattr_ibody_header *header;
+	struct ext3_xattr_entry *entry;
+	struct ext3_inode *raw_inode;
+	struct ext3_iloc iloc;
+	size_t size;
+	void *end;
+	int error;
+
+	if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
+		return -ENODATA;
+	error = ext3_get_inode_loc(inode, &iloc);
+	if (error)
+		return error;
+	raw_inode = ext3_raw_inode(&iloc);
+	header = IHDR(inode, raw_inode);
+	entry = IFIRST(header);
+	end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
+	error = ext3_xattr_check_names(entry, end);
+	if (error)
+		goto cleanup;
+	error = ext3_xattr_find_entry(&entry, name_index, name,
+				      end - (void *)entry, 0);
+	if (error)
+		goto cleanup;
+	size = le32_to_cpu(entry->e_value_size);
+	if (buffer) {
+		error = -ERANGE;
+		if (size > buffer_size)
+			goto cleanup;
+		memcpy(buffer, (void *)IFIRST(header) +
+		       le16_to_cpu(entry->e_value_offs), size);
+	}
+	error = size;
+
+cleanup:
+	brelse(iloc.bh);
+	return error;
+}
+
+/*
+ * ext3_xattr_get()
+ *
+ * Copy an extended attribute into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+int
+ext3_xattr_get(struct inode *inode, int name_index, const char *name,
+	       void *buffer, size_t buffer_size)
+{
+	int error;
+
+	down_read(&EXT3_I(inode)->xattr_sem);
+	error = ext3_xattr_ibody_get(inode, name_index, name, buffer,
+				     buffer_size);
+	if (error == -ENODATA)
+		error = ext3_xattr_block_get(inode, name_index, name, buffer,
+					     buffer_size);
+	up_read(&EXT3_I(inode)->xattr_sem);
+	return error;
+}
+
+static int
+ext3_xattr_list_entries(struct dentry *dentry, struct ext3_xattr_entry *entry,
+			char *buffer, size_t buffer_size)
+{
+	size_t rest = buffer_size;
+
+	for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
+		const struct xattr_handler *handler =
+			ext3_xattr_handler(entry->e_name_index);
+
+		if (handler) {
+			size_t size = handler->list(dentry, buffer, rest,
+						    entry->e_name,
+						    entry->e_name_len,
+						    handler->flags);
+			if (buffer) {
+				if (size > rest)
+					return -ERANGE;
+				buffer += size;
+			}
+			rest -= size;
+		}
+	}
+	return buffer_size - rest;
+}
+
+static int
+ext3_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	struct inode *inode = d_inode(dentry);
+	struct buffer_head *bh = NULL;
+	int error;
+
+	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
+		  buffer, (long)buffer_size);
+
+	error = 0;
+	if (!EXT3_I(inode)->i_file_acl)
+		goto cleanup;
+	ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
+	bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
+	error = -EIO;
+	if (!bh)
+		goto cleanup;
+	ea_bdebug(bh, "b_count=%d, refcount=%d",
+		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
+	if (ext3_xattr_check_block(bh)) {
+		ext3_error(inode->i_sb, __func__,
+			   "inode %lu: bad block "E3FSBLK, inode->i_ino,
+			   EXT3_I(inode)->i_file_acl);
+		error = -EIO;
+		goto cleanup;
+	}
+	ext3_xattr_cache_insert(bh);
+	error = ext3_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
+
+cleanup:
+	brelse(bh);
+
+	return error;
+}
+
+static int
+ext3_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ext3_xattr_ibody_header *header;
+	struct ext3_inode *raw_inode;
+	struct ext3_iloc iloc;
+	void *end;
+	int error;
+
+	if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
+		return 0;
+	error = ext3_get_inode_loc(inode, &iloc);
+	if (error)
+		return error;
+	raw_inode = ext3_raw_inode(&iloc);
+	header = IHDR(inode, raw_inode);
+	end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
+	error = ext3_xattr_check_names(IFIRST(header), end);
+	if (error)
+		goto cleanup;
+	error = ext3_xattr_list_entries(dentry, IFIRST(header),
+					buffer, buffer_size);
+
+cleanup:
+	brelse(iloc.bh);
+	return error;
+}
+
+/*
+ * ext3_xattr_list()
+ *
+ * Copy a list of attribute names into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+static int
+ext3_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	int i_error, b_error;
+
+	down_read(&EXT3_I(d_inode(dentry))->xattr_sem);
+	i_error = ext3_xattr_ibody_list(dentry, buffer, buffer_size);
+	if (i_error < 0) {
+		b_error = 0;
+	} else {
+		if (buffer) {
+			buffer += i_error;
+			buffer_size -= i_error;
+		}
+		b_error = ext3_xattr_block_list(dentry, buffer, buffer_size);
+		if (b_error < 0)
+			i_error = 0;
+	}
+	up_read(&EXT3_I(d_inode(dentry))->xattr_sem);
+	return i_error + b_error;
+}
+
+/*
+ * If the EXT3_FEATURE_COMPAT_EXT_ATTR feature of this file system is
+ * not set, set it.
+ */
+static void ext3_xattr_update_super_block(handle_t *handle,
+					  struct super_block *sb)
+{
+	if (EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR))
+		return;
+
+	if (ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh) == 0) {
+		EXT3_SET_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR);
+		ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
+	}
+}
+
+/*
+ * Release the xattr block BH: If the reference count is > 1, decrement
+ * it; otherwise free the block.
+ */
+static void
+ext3_xattr_release_block(handle_t *handle, struct inode *inode,
+			 struct buffer_head *bh)
+{
+	struct mb_cache_entry *ce = NULL;
+	int error = 0;
+
+	ce = mb_cache_entry_get(ext3_xattr_cache, bh->b_bdev, bh->b_blocknr);
+	error = ext3_journal_get_write_access(handle, bh);
+	if (error)
+		 goto out;
+
+	lock_buffer(bh);
+
+	if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
+		ea_bdebug(bh, "refcount now=0; freeing");
+		if (ce)
+			mb_cache_entry_free(ce);
+		ext3_free_blocks(handle, inode, bh->b_blocknr, 1);
+		get_bh(bh);
+		ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
+	} else {
+		le32_add_cpu(&BHDR(bh)->h_refcount, -1);
+		error = ext3_journal_dirty_metadata(handle, bh);
+		if (IS_SYNC(inode))
+			handle->h_sync = 1;
+		dquot_free_block(inode, 1);
+		ea_bdebug(bh, "refcount now=%d; releasing",
+			  le32_to_cpu(BHDR(bh)->h_refcount));
+		if (ce)
+			mb_cache_entry_release(ce);
+	}
+	unlock_buffer(bh);
+out:
+	ext3_std_error(inode->i_sb, error);
+	return;
+}
+
+struct ext3_xattr_info {
+	int name_index;
+	const char *name;
+	const void *value;
+	size_t value_len;
+};
+
+struct ext3_xattr_search {
+	struct ext3_xattr_entry *first;
+	void *base;
+	void *end;
+	struct ext3_xattr_entry *here;
+	int not_found;
+};
+
+static int
+ext3_xattr_set_entry(struct ext3_xattr_info *i, struct ext3_xattr_search *s)
+{
+	struct ext3_xattr_entry *last;
+	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
+
+	/* Compute min_offs and last. */
+	last = s->first;
+	for (; !IS_LAST_ENTRY(last); last = EXT3_XATTR_NEXT(last)) {
+		if (!last->e_value_block && last->e_value_size) {
+			size_t offs = le16_to_cpu(last->e_value_offs);
+			if (offs < min_offs)
+				min_offs = offs;
+		}
+	}
+	free = min_offs - ((void *)last - s->base) - sizeof(__u32);
+	if (!s->not_found) {
+		if (!s->here->e_value_block && s->here->e_value_size) {
+			size_t size = le32_to_cpu(s->here->e_value_size);
+			free += EXT3_XATTR_SIZE(size);
+		}
+		free += EXT3_XATTR_LEN(name_len);
+	}
+	if (i->value) {
+		if (free < EXT3_XATTR_LEN(name_len) +
+			   EXT3_XATTR_SIZE(i->value_len))
+			return -ENOSPC;
+	}
+
+	if (i->value && s->not_found) {
+		/* Insert the new name. */
+		size_t size = EXT3_XATTR_LEN(name_len);
+		size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
+		memmove((void *)s->here + size, s->here, rest);
+		memset(s->here, 0, size);
+		s->here->e_name_index = i->name_index;
+		s->here->e_name_len = name_len;
+		memcpy(s->here->e_name, i->name, name_len);
+	} else {
+		if (!s->here->e_value_block && s->here->e_value_size) {
+			void *first_val = s->base + min_offs;
+			size_t offs = le16_to_cpu(s->here->e_value_offs);
+			void *val = s->base + offs;
+			size_t size = EXT3_XATTR_SIZE(
+				le32_to_cpu(s->here->e_value_size));
+
+			if (i->value && size == EXT3_XATTR_SIZE(i->value_len)) {
+				/* The old and the new value have the same
+				   size. Just replace. */
+				s->here->e_value_size =
+					cpu_to_le32(i->value_len);
+				memset(val + size - EXT3_XATTR_PAD, 0,
+				       EXT3_XATTR_PAD); /* Clear pad bytes. */
+				memcpy(val, i->value, i->value_len);
+				return 0;
+			}
+
+			/* Remove the old value. */
+			memmove(first_val + size, first_val, val - first_val);
+			memset(first_val, 0, size);
+			s->here->e_value_size = 0;
+			s->here->e_value_offs = 0;
+			min_offs += size;
+
+			/* Adjust all value offsets. */
+			last = s->first;
+			while (!IS_LAST_ENTRY(last)) {
+				size_t o = le16_to_cpu(last->e_value_offs);
+				if (!last->e_value_block &&
+				    last->e_value_size && o < offs)
+					last->e_value_offs =
+						cpu_to_le16(o + size);
+				last = EXT3_XATTR_NEXT(last);
+			}
+		}
+		if (!i->value) {
+			/* Remove the old name. */
+			size_t size = EXT3_XATTR_LEN(name_len);
+			last = ENTRY((void *)last - size);
+			memmove(s->here, (void *)s->here + size,
+				(void *)last - (void *)s->here + sizeof(__u32));
+			memset(last, 0, size);
+		}
+	}
+
+	if (i->value) {
+		/* Insert the new value. */
+		s->here->e_value_size = cpu_to_le32(i->value_len);
+		if (i->value_len) {
+			size_t size = EXT3_XATTR_SIZE(i->value_len);
+			void *val = s->base + min_offs - size;
+			s->here->e_value_offs = cpu_to_le16(min_offs - size);
+			memset(val + size - EXT3_XATTR_PAD, 0,
+			       EXT3_XATTR_PAD); /* Clear the pad bytes. */
+			memcpy(val, i->value, i->value_len);
+		}
+	}
+	return 0;
+}
+
+struct ext3_xattr_block_find {
+	struct ext3_xattr_search s;
+	struct buffer_head *bh;
+};
+
+static int
+ext3_xattr_block_find(struct inode *inode, struct ext3_xattr_info *i,
+		      struct ext3_xattr_block_find *bs)
+{
+	struct super_block *sb = inode->i_sb;
+	int error;
+
+	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
+		  i->name_index, i->name, i->value, (long)i->value_len);
+
+	if (EXT3_I(inode)->i_file_acl) {
+		/* The inode already has an extended attribute block. */
+		bs->bh = sb_bread(sb, EXT3_I(inode)->i_file_acl);
+		error = -EIO;
+		if (!bs->bh)
+			goto cleanup;
+		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
+			atomic_read(&(bs->bh->b_count)),
+			le32_to_cpu(BHDR(bs->bh)->h_refcount));
+		if (ext3_xattr_check_block(bs->bh)) {
+			ext3_error(sb, __func__,
+				"inode %lu: bad block "E3FSBLK, inode->i_ino,
+				EXT3_I(inode)->i_file_acl);
+			error = -EIO;
+			goto cleanup;
+		}
+		/* Find the named attribute. */
+		bs->s.base = BHDR(bs->bh);
+		bs->s.first = BFIRST(bs->bh);
+		bs->s.end = bs->bh->b_data + bs->bh->b_size;
+		bs->s.here = bs->s.first;
+		error = ext3_xattr_find_entry(&bs->s.here, i->name_index,
+					      i->name, bs->bh->b_size, 1);
+		if (error && error != -ENODATA)
+			goto cleanup;
+		bs->s.not_found = error;
+	}
+	error = 0;
+
+cleanup:
+	return error;
+}
+
+static int
+ext3_xattr_block_set(handle_t *handle, struct inode *inode,
+		     struct ext3_xattr_info *i,
+		     struct ext3_xattr_block_find *bs)
+{
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *new_bh = NULL;
+	struct ext3_xattr_search *s = &bs->s;
+	struct mb_cache_entry *ce = NULL;
+	int error = 0;
+
+#define header(x) ((struct ext3_xattr_header *)(x))
+
+	if (i->value && i->value_len > sb->s_blocksize)
+		return -ENOSPC;
+	if (s->base) {
+		ce = mb_cache_entry_get(ext3_xattr_cache, bs->bh->b_bdev,
+					bs->bh->b_blocknr);
+		error = ext3_journal_get_write_access(handle, bs->bh);
+		if (error)
+			goto cleanup;
+		lock_buffer(bs->bh);
+
+		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
+			if (ce) {
+				mb_cache_entry_free(ce);
+				ce = NULL;
+			}
+			ea_bdebug(bs->bh, "modifying in-place");
+			error = ext3_xattr_set_entry(i, s);
+			if (!error) {
+				if (!IS_LAST_ENTRY(s->first))
+					ext3_xattr_rehash(header(s->base),
+							  s->here);
+				ext3_xattr_cache_insert(bs->bh);
+			}
+			unlock_buffer(bs->bh);
+			if (error == -EIO)
+				goto bad_block;
+			if (!error)
+				error = ext3_journal_dirty_metadata(handle,
+								    bs->bh);
+			if (error)
+				goto cleanup;
+			goto inserted;
+		} else {
+			int offset = (char *)s->here - bs->bh->b_data;
+
+			unlock_buffer(bs->bh);
+			journal_release_buffer(handle, bs->bh);
+
+			if (ce) {
+				mb_cache_entry_release(ce);
+				ce = NULL;
+			}
+			ea_bdebug(bs->bh, "cloning");
+			s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
+			error = -ENOMEM;
+			if (s->base == NULL)
+				goto cleanup;
+			memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
+			s->first = ENTRY(header(s->base)+1);
+			header(s->base)->h_refcount = cpu_to_le32(1);
+			s->here = ENTRY(s->base + offset);
+			s->end = s->base + bs->bh->b_size;
+		}
+	} else {
+		/* Allocate a buffer where we construct the new block. */
+		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
+		/* assert(header == s->base) */
+		error = -ENOMEM;
+		if (s->base == NULL)
+			goto cleanup;
+		header(s->base)->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
+		header(s->base)->h_blocks = cpu_to_le32(1);
+		header(s->base)->h_refcount = cpu_to_le32(1);
+		s->first = ENTRY(header(s->base)+1);
+		s->here = ENTRY(header(s->base)+1);
+		s->end = s->base + sb->s_blocksize;
+	}
+
+	error = ext3_xattr_set_entry(i, s);
+	if (error == -EIO)
+		goto bad_block;
+	if (error)
+		goto cleanup;
+	if (!IS_LAST_ENTRY(s->first))
+		ext3_xattr_rehash(header(s->base), s->here);
+
+inserted:
+	if (!IS_LAST_ENTRY(s->first)) {
+		new_bh = ext3_xattr_cache_find(inode, header(s->base), &ce);
+		if (new_bh) {
+			/* We found an identical block in the cache. */
+			if (new_bh == bs->bh)
+				ea_bdebug(new_bh, "keeping");
+			else {
+				/* The old block is released after updating
+				   the inode. */
+				error = dquot_alloc_block(inode, 1);
+				if (error)
+					goto cleanup;
+				error = ext3_journal_get_write_access(handle,
+								      new_bh);
+				if (error)
+					goto cleanup_dquot;
+				lock_buffer(new_bh);
+				le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
+				ea_bdebug(new_bh, "reusing; refcount now=%d",
+					le32_to_cpu(BHDR(new_bh)->h_refcount));
+				unlock_buffer(new_bh);
+				error = ext3_journal_dirty_metadata(handle,
+								    new_bh);
+				if (error)
+					goto cleanup_dquot;
+			}
+			mb_cache_entry_release(ce);
+			ce = NULL;
+		} else if (bs->bh && s->base == bs->bh->b_data) {
+			/* We were modifying this block in-place. */
+			ea_bdebug(bs->bh, "keeping this block");
+			new_bh = bs->bh;
+			get_bh(new_bh);
+		} else {
+			/* We need to allocate a new block */
+			ext3_fsblk_t goal = ext3_group_first_block_no(sb,
+						EXT3_I(inode)->i_block_group);
+			ext3_fsblk_t block;
+
+			/*
+			 * Protect us agaist concurrent allocations to the
+			 * same inode from ext3_..._writepage(). Reservation
+			 * code does not expect racing allocations.
+			 */
+			mutex_lock(&EXT3_I(inode)->truncate_mutex);
+			block = ext3_new_block(handle, inode, goal, &error);
+			mutex_unlock(&EXT3_I(inode)->truncate_mutex);
+			if (error)
+				goto cleanup;
+			ea_idebug(inode, "creating block %d", block);
+
+			new_bh = sb_getblk(sb, block);
+			if (unlikely(!new_bh)) {
+getblk_failed:
+				ext3_free_blocks(handle, inode, block, 1);
+				error = -ENOMEM;
+				goto cleanup;
+			}
+			lock_buffer(new_bh);
+			error = ext3_journal_get_create_access(handle, new_bh);
+			if (error) {
+				unlock_buffer(new_bh);
+				goto getblk_failed;
+			}
+			memcpy(new_bh->b_data, s->base, new_bh->b_size);
+			set_buffer_uptodate(new_bh);
+			unlock_buffer(new_bh);
+			ext3_xattr_cache_insert(new_bh);
+			error = ext3_journal_dirty_metadata(handle, new_bh);
+			if (error)
+				goto cleanup;
+		}
+	}
+
+	/* Update the inode. */
+	EXT3_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
+
+	/* Drop the previous xattr block. */
+	if (bs->bh && bs->bh != new_bh)
+		ext3_xattr_release_block(handle, inode, bs->bh);
+	error = 0;
+
+cleanup:
+	if (ce)
+		mb_cache_entry_release(ce);
+	brelse(new_bh);
+	if (!(bs->bh && s->base == bs->bh->b_data))
+		kfree(s->base);
+
+	return error;
+
+cleanup_dquot:
+	dquot_free_block(inode, 1);
+	goto cleanup;
+
+bad_block:
+	ext3_error(inode->i_sb, __func__,
+		   "inode %lu: bad block "E3FSBLK, inode->i_ino,
+		   EXT3_I(inode)->i_file_acl);
+	goto cleanup;
+
+#undef header
+}
+
+struct ext3_xattr_ibody_find {
+	struct ext3_xattr_search s;
+	struct ext3_iloc iloc;
+};
+
+static int
+ext3_xattr_ibody_find(struct inode *inode, struct ext3_xattr_info *i,
+		      struct ext3_xattr_ibody_find *is)
+{
+	struct ext3_xattr_ibody_header *header;
+	struct ext3_inode *raw_inode;
+	int error;
+
+	if (EXT3_I(inode)->i_extra_isize == 0)
+		return 0;
+	raw_inode = ext3_raw_inode(&is->iloc);
+	header = IHDR(inode, raw_inode);
+	is->s.base = is->s.first = IFIRST(header);
+	is->s.here = is->s.first;
+	is->s.end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
+	if (ext3_test_inode_state(inode, EXT3_STATE_XATTR)) {
+		error = ext3_xattr_check_names(IFIRST(header), is->s.end);
+		if (error)
+			return error;
+		/* Find the named attribute. */
+		error = ext3_xattr_find_entry(&is->s.here, i->name_index,
+					      i->name, is->s.end -
+					      (void *)is->s.base, 0);
+		if (error && error != -ENODATA)
+			return error;
+		is->s.not_found = error;
+	}
+	return 0;
+}
+
+static int
+ext3_xattr_ibody_set(handle_t *handle, struct inode *inode,
+		     struct ext3_xattr_info *i,
+		     struct ext3_xattr_ibody_find *is)
+{
+	struct ext3_xattr_ibody_header *header;
+	struct ext3_xattr_search *s = &is->s;
+	int error;
+
+	if (EXT3_I(inode)->i_extra_isize == 0)
+		return -ENOSPC;
+	error = ext3_xattr_set_entry(i, s);
+	if (error)
+		return error;
+	header = IHDR(inode, ext3_raw_inode(&is->iloc));
+	if (!IS_LAST_ENTRY(s->first)) {
+		header->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
+		ext3_set_inode_state(inode, EXT3_STATE_XATTR);
+	} else {
+		header->h_magic = cpu_to_le32(0);
+		ext3_clear_inode_state(inode, EXT3_STATE_XATTR);
+	}
+	return 0;
+}
+
+/*
+ * ext3_xattr_set_handle()
+ *
+ * Create, replace or remove an extended attribute for this inode.  Value
+ * is NULL to remove an existing extended attribute, and non-NULL to
+ * either replace an existing extended attribute, or create a new extended
+ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
+ * specify that an extended attribute must exist and must not exist
+ * previous to the call, respectively.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext3_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
+		      const char *name, const void *value, size_t value_len,
+		      int flags)
+{
+	struct ext3_xattr_info i = {
+		.name_index = name_index,
+		.name = name,
+		.value = value,
+		.value_len = value_len,
+
+	};
+	struct ext3_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext3_xattr_block_find bs = {
+		.s = { .not_found = -ENODATA, },
+	};
+	int error;
+
+	if (!name)
+		return -EINVAL;
+	if (strlen(name) > 255)
+		return -ERANGE;
+	down_write(&EXT3_I(inode)->xattr_sem);
+	error = ext3_get_inode_loc(inode, &is.iloc);
+	if (error)
+		goto cleanup;
+
+	error = ext3_journal_get_write_access(handle, is.iloc.bh);
+	if (error)
+		goto cleanup;
+
+	if (ext3_test_inode_state(inode, EXT3_STATE_NEW)) {
+		struct ext3_inode *raw_inode = ext3_raw_inode(&is.iloc);
+		memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
+		ext3_clear_inode_state(inode, EXT3_STATE_NEW);
+	}
+
+	error = ext3_xattr_ibody_find(inode, &i, &is);
+	if (error)
+		goto cleanup;
+	if (is.s.not_found)
+		error = ext3_xattr_block_find(inode, &i, &bs);
+	if (error)
+		goto cleanup;
+	if (is.s.not_found && bs.s.not_found) {
+		error = -ENODATA;
+		if (flags & XATTR_REPLACE)
+			goto cleanup;
+		error = 0;
+		if (!value)
+			goto cleanup;
+	} else {
+		error = -EEXIST;
+		if (flags & XATTR_CREATE)
+			goto cleanup;
+	}
+	if (!value) {
+		if (!is.s.not_found)
+			error = ext3_xattr_ibody_set(handle, inode, &i, &is);
+		else if (!bs.s.not_found)
+			error = ext3_xattr_block_set(handle, inode, &i, &bs);
+	} else {
+		error = ext3_xattr_ibody_set(handle, inode, &i, &is);
+		if (!error && !bs.s.not_found) {
+			i.value = NULL;
+			error = ext3_xattr_block_set(handle, inode, &i, &bs);
+		} else if (error == -ENOSPC) {
+			if (EXT3_I(inode)->i_file_acl && !bs.s.base) {
+				error = ext3_xattr_block_find(inode, &i, &bs);
+				if (error)
+					goto cleanup;
+			}
+			error = ext3_xattr_block_set(handle, inode, &i, &bs);
+			if (error)
+				goto cleanup;
+			if (!is.s.not_found) {
+				i.value = NULL;
+				error = ext3_xattr_ibody_set(handle, inode, &i,
+							     &is);
+			}
+		}
+	}
+	if (!error) {
+		ext3_xattr_update_super_block(handle, inode->i_sb);
+		inode->i_ctime = CURRENT_TIME_SEC;
+		error = ext3_mark_iloc_dirty(handle, inode, &is.iloc);
+		/*
+		 * The bh is consumed by ext3_mark_iloc_dirty, even with
+		 * error != 0.
+		 */
+		is.iloc.bh = NULL;
+		if (IS_SYNC(inode))
+			handle->h_sync = 1;
+	}
+
+cleanup:
+	brelse(is.iloc.bh);
+	brelse(bs.bh);
+	up_write(&EXT3_I(inode)->xattr_sem);
+	return error;
+}
+
+/*
+ * ext3_xattr_set()
+ *
+ * Like ext3_xattr_set_handle, but start from an inode. This extended
+ * attribute modification is a filesystem transaction by itself.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext3_xattr_set(struct inode *inode, int name_index, const char *name,
+	       const void *value, size_t value_len, int flags)
+{
+	handle_t *handle;
+	int error, retries = 0;
+
+retry:
+	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
+	if (IS_ERR(handle)) {
+		error = PTR_ERR(handle);
+	} else {
+		int error2;
+
+		error = ext3_xattr_set_handle(handle, inode, name_index, name,
+					      value, value_len, flags);
+		error2 = ext3_journal_stop(handle);
+		if (error == -ENOSPC &&
+		    ext3_should_retry_alloc(inode->i_sb, &retries))
+			goto retry;
+		if (error == 0)
+			error = error2;
+	}
+
+	return error;
+}
+
+/*
+ * ext3_xattr_delete_inode()
+ *
+ * Free extended attribute resources associated with this inode. This
+ * is called immediately before an inode is freed. We have exclusive
+ * access to the inode.
+ */
+void
+ext3_xattr_delete_inode(handle_t *handle, struct inode *inode)
+{
+	struct buffer_head *bh = NULL;
+
+	if (!EXT3_I(inode)->i_file_acl)
+		goto cleanup;
+	bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
+	if (!bh) {
+		ext3_error(inode->i_sb, __func__,
+			"inode %lu: block "E3FSBLK" read error", inode->i_ino,
+			EXT3_I(inode)->i_file_acl);
+		goto cleanup;
+	}
+	if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
+	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
+		ext3_error(inode->i_sb, __func__,
+			"inode %lu: bad block "E3FSBLK, inode->i_ino,
+			EXT3_I(inode)->i_file_acl);
+		goto cleanup;
+	}
+	ext3_xattr_release_block(handle, inode, bh);
+	EXT3_I(inode)->i_file_acl = 0;
+
+cleanup:
+	brelse(bh);
+}
+
+/*
+ * ext3_xattr_put_super()
+ *
+ * This is called when a file system is unmounted.
+ */
+void
+ext3_xattr_put_super(struct super_block *sb)
+{
+	mb_cache_shrink(sb->s_bdev);
+}
+
+/*
+ * ext3_xattr_cache_insert()
+ *
+ * Create a new entry in the extended attribute cache, and insert
+ * it unless such an entry is already in the cache.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+static void
+ext3_xattr_cache_insert(struct buffer_head *bh)
+{
+	__u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
+	struct mb_cache_entry *ce;
+	int error;
+
+	ce = mb_cache_entry_alloc(ext3_xattr_cache, GFP_NOFS);
+	if (!ce) {
+		ea_bdebug(bh, "out of memory");
+		return;
+	}
+	error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
+	if (error) {
+		mb_cache_entry_free(ce);
+		if (error == -EBUSY) {
+			ea_bdebug(bh, "already in cache");
+			error = 0;
+		}
+	} else {
+		ea_bdebug(bh, "inserting [%x]", (int)hash);
+		mb_cache_entry_release(ce);
+	}
+}
+
+/*
+ * ext3_xattr_cmp()
+ *
+ * Compare two extended attribute blocks for equality.
+ *
+ * Returns 0 if the blocks are equal, 1 if they differ, and
+ * a negative error number on errors.
+ */
+static int
+ext3_xattr_cmp(struct ext3_xattr_header *header1,
+	       struct ext3_xattr_header *header2)
+{
+	struct ext3_xattr_entry *entry1, *entry2;
+
+	entry1 = ENTRY(header1+1);
+	entry2 = ENTRY(header2+1);
+	while (!IS_LAST_ENTRY(entry1)) {
+		if (IS_LAST_ENTRY(entry2))
+			return 1;
+		if (entry1->e_hash != entry2->e_hash ||
+		    entry1->e_name_index != entry2->e_name_index ||
+		    entry1->e_name_len != entry2->e_name_len ||
+		    entry1->e_value_size != entry2->e_value_size ||
+		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
+			return 1;
+		if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
+			return -EIO;
+		if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
+			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
+			   le32_to_cpu(entry1->e_value_size)))
+			return 1;
+
+		entry1 = EXT3_XATTR_NEXT(entry1);
+		entry2 = EXT3_XATTR_NEXT(entry2);
+	}
+	if (!IS_LAST_ENTRY(entry2))
+		return 1;
+	return 0;
+}
+
+/*
+ * ext3_xattr_cache_find()
+ *
+ * Find an identical extended attribute block.
+ *
+ * Returns a pointer to the block found, or NULL if such a block was
+ * not found or an error occurred.
+ */
+static struct buffer_head *
+ext3_xattr_cache_find(struct inode *inode, struct ext3_xattr_header *header,
+		      struct mb_cache_entry **pce)
+{
+	__u32 hash = le32_to_cpu(header->h_hash);
+	struct mb_cache_entry *ce;
+
+	if (!header->h_hash)
+		return NULL;  /* never share */
+	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
+again:
+	ce = mb_cache_entry_find_first(ext3_xattr_cache, inode->i_sb->s_bdev,
+				       hash);
+	while (ce) {
+		struct buffer_head *bh;
+
+		if (IS_ERR(ce)) {
+			if (PTR_ERR(ce) == -EAGAIN)
+				goto again;
+			break;
+		}
+		bh = sb_bread(inode->i_sb, ce->e_block);
+		if (!bh) {
+			ext3_error(inode->i_sb, __func__,
+				"inode %lu: block %lu read error",
+				inode->i_ino, (unsigned long) ce->e_block);
+		} else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
+				EXT3_XATTR_REFCOUNT_MAX) {
+			ea_idebug(inode, "block %lu refcount %d>=%d",
+				  (unsigned long) ce->e_block,
+				  le32_to_cpu(BHDR(bh)->h_refcount),
+					  EXT3_XATTR_REFCOUNT_MAX);
+		} else if (ext3_xattr_cmp(header, BHDR(bh)) == 0) {
+			*pce = ce;
+			return bh;
+		}
+		brelse(bh);
+		ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
+	}
+	return NULL;
+}
+
+#define NAME_HASH_SHIFT 5
+#define VALUE_HASH_SHIFT 16
+
+/*
+ * ext3_xattr_hash_entry()
+ *
+ * Compute the hash of an extended attribute.
+ */
+static inline void ext3_xattr_hash_entry(struct ext3_xattr_header *header,
+					 struct ext3_xattr_entry *entry)
+{
+	__u32 hash = 0;
+	char *name = entry->e_name;
+	int n;
+
+	for (n=0; n < entry->e_name_len; n++) {
+		hash = (hash << NAME_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
+		       *name++;
+	}
+
+	if (entry->e_value_block == 0 && entry->e_value_size != 0) {
+		__le32 *value = (__le32 *)((char *)header +
+			le16_to_cpu(entry->e_value_offs));
+		for (n = (le32_to_cpu(entry->e_value_size) +
+		     EXT3_XATTR_ROUND) >> EXT3_XATTR_PAD_BITS; n; n--) {
+			hash = (hash << VALUE_HASH_SHIFT) ^
+			       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
+			       le32_to_cpu(*value++);
+		}
+	}
+	entry->e_hash = cpu_to_le32(hash);
+}
+
+#undef NAME_HASH_SHIFT
+#undef VALUE_HASH_SHIFT
+
+#define BLOCK_HASH_SHIFT 16
+
+/*
+ * ext3_xattr_rehash()
+ *
+ * Re-compute the extended attribute hash value after an entry has changed.
+ */
+static void ext3_xattr_rehash(struct ext3_xattr_header *header,
+			      struct ext3_xattr_entry *entry)
+{
+	struct ext3_xattr_entry *here;
+	__u32 hash = 0;
+
+	ext3_xattr_hash_entry(header, entry);
+	here = ENTRY(header+1);
+	while (!IS_LAST_ENTRY(here)) {
+		if (!here->e_hash) {
+			/* Block is not shared if an entry's hash value == 0 */
+			hash = 0;
+			break;
+		}
+		hash = (hash << BLOCK_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
+		       le32_to_cpu(here->e_hash);
+		here = EXT3_XATTR_NEXT(here);
+	}
+	header->h_hash = cpu_to_le32(hash);
+}
+
+#undef BLOCK_HASH_SHIFT
+
+int __init
+init_ext3_xattr(void)
+{
+	ext3_xattr_cache = mb_cache_create("ext3_xattr", 6);
+	if (!ext3_xattr_cache)
+		return -ENOMEM;
+	return 0;
+}
+
+void
+exit_ext3_xattr(void)
+{
+	if (ext3_xattr_cache)
+		mb_cache_destroy(ext3_xattr_cache);
+	ext3_xattr_cache = NULL;
+}