xattr.c 42.0 KB
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/*
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 * linux/fs/ext4/xattr.c
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 *
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 *
 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
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 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
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 * 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
 * ----------------
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 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
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 * 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 <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/mbcache.h>
#include <linux/quotaops.h>
#include <linux/rwsem.h>
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#include "ext4_jbd2.h"
#include "ext4.h"
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#include "xattr.h"
#include "acl.h"

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#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
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#define BFIRST(bh) ENTRY(BHDR(bh)+1)
#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)

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#ifdef EXT4_XATTR_DEBUG
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# 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

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static void ext4_xattr_cache_insert(struct buffer_head *);
static struct buffer_head *ext4_xattr_cache_find(struct inode *,
						 struct ext4_xattr_header *,
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						 struct mb_cache_entry **);
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static void ext4_xattr_rehash(struct ext4_xattr_header *,
			      struct ext4_xattr_entry *);
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static int ext4_xattr_list(struct dentry *dentry, char *buffer,
96
			   size_t buffer_size);
97

98
static struct mb_cache *ext4_xattr_cache;
99

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static const struct xattr_handler *ext4_xattr_handler_map[] = {
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	[EXT4_XATTR_INDEX_USER]		     = &ext4_xattr_user_handler,
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#ifdef CONFIG_EXT4_FS_POSIX_ACL
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	[EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
	[EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
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#endif
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	[EXT4_XATTR_INDEX_TRUSTED]	     = &ext4_xattr_trusted_handler,
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#ifdef CONFIG_EXT4_FS_SECURITY
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	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
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#endif
};

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const struct xattr_handler *ext4_xattr_handlers[] = {
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	&ext4_xattr_user_handler,
	&ext4_xattr_trusted_handler,
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#ifdef CONFIG_EXT4_FS_POSIX_ACL
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	&ext4_xattr_acl_access_handler,
	&ext4_xattr_acl_default_handler,
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#endif
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#ifdef CONFIG_EXT4_FS_SECURITY
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	&ext4_xattr_security_handler,
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#endif
	NULL
};

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static inline const struct xattr_handler *
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ext4_xattr_handler(int name_index)
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{
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	const struct xattr_handler *handler = NULL;
129

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	if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
		handler = ext4_xattr_handler_map[name_index];
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	return handler;
}

/*
 * Inode operation listxattr()
 *
 * dentry->d_inode->i_mutex: don't care
 */
ssize_t
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ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
142
{
143
	return ext4_xattr_list(dentry, buffer, size);
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}

static int
147
ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
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{
	while (!IS_LAST_ENTRY(entry)) {
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		struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
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		if ((void *)next >= end)
			return -EIO;
		entry = next;
	}
	return 0;
}

static inline int
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ext4_xattr_check_block(struct buffer_head *bh)
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{
	int error;

163
	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
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	    BHDR(bh)->h_blocks != cpu_to_le32(1))
		return -EIO;
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	error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
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	return error;
}

static inline int
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ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
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{
	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
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ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
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		      const char *name, size_t size, int sorted)
{
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	struct ext4_xattr_entry *entry;
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	size_t name_len;
	int cmp = 1;

	if (name == NULL)
		return -EINVAL;
	name_len = strlen(name);
	entry = *pentry;
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	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
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		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;
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	if (!cmp && ext4_xattr_check_entry(entry, size))
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			return -EIO;
	return cmp ? -ENODATA : 0;
}

static int
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ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
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		     void *buffer, size_t buffer_size)
{
	struct buffer_head *bh = NULL;
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	struct ext4_xattr_entry *entry;
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	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;
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	if (!EXT4_I(inode)->i_file_acl)
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		goto cleanup;
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	ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
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	if (!bh)
		goto cleanup;
	ea_bdebug(bh, "b_count=%d, refcount=%d",
		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
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	if (ext4_xattr_check_block(bh)) {
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bad_block:
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		EXT4_ERROR_INODE(inode, "bad block %llu",
				 EXT4_I(inode)->i_file_acl);
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		error = -EIO;
		goto cleanup;
	}
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	ext4_xattr_cache_insert(bh);
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	entry = BFIRST(bh);
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	error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
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	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
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ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
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		     void *buffer, size_t buffer_size)
{
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	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_entry *entry;
	struct ext4_inode *raw_inode;
	struct ext4_iloc iloc;
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	size_t size;
	void *end;
	int error;

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	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
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		return -ENODATA;
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	error = ext4_get_inode_loc(inode, &iloc);
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	if (error)
		return error;
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	raw_inode = ext4_raw_inode(&iloc);
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	header = IHDR(inode, raw_inode);
	entry = IFIRST(header);
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	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
	error = ext4_xattr_check_names(entry, end);
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	if (error)
		goto cleanup;
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	error = ext4_xattr_find_entry(&entry, name_index, name,
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				      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;
}

/*
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 * ext4_xattr_get()
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 *
 * 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
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ext4_xattr_get(struct inode *inode, int name_index, const char *name,
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	       void *buffer, size_t buffer_size)
{
	int error;

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	down_read(&EXT4_I(inode)->xattr_sem);
	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
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				     buffer_size);
	if (error == -ENODATA)
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		error = ext4_xattr_block_get(inode, name_index, name, buffer,
322
					     buffer_size);
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	up_read(&EXT4_I(inode)->xattr_sem);
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	return error;
}

static int
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ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
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			char *buffer, size_t buffer_size)
{
	size_t rest = buffer_size;

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	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
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Stephen Hemminger 已提交
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		const struct xattr_handler *handler =
335
			ext4_xattr_handler(entry->e_name_index);
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		if (handler) {
338
			size_t size = handler->list(dentry, buffer, rest,
339
						    entry->e_name,
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						    entry->e_name_len,
						    handler->flags);
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			if (buffer) {
				if (size > rest)
					return -ERANGE;
				buffer += size;
			}
			rest -= size;
		}
	}
	return buffer_size - rest;
}

static int
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ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
355
{
356
	struct inode *inode = dentry->d_inode;
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	struct buffer_head *bh = NULL;
	int error;

	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
		  buffer, (long)buffer_size);

	error = 0;
364
	if (!EXT4_I(inode)->i_file_acl)
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		goto cleanup;
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	ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
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	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));
373
	if (ext4_xattr_check_block(bh)) {
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		EXT4_ERROR_INODE(inode, "bad block %llu",
				 EXT4_I(inode)->i_file_acl);
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		error = -EIO;
		goto cleanup;
	}
379
	ext4_xattr_cache_insert(bh);
380
	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
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cleanup:
	brelse(bh);

	return error;
}

static int
389
ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
390
{
391
	struct inode *inode = dentry->d_inode;
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	struct ext4_xattr_ibody_header *header;
	struct ext4_inode *raw_inode;
	struct ext4_iloc iloc;
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	void *end;
	int error;

398
	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
399
		return 0;
400
	error = ext4_get_inode_loc(inode, &iloc);
401 402
	if (error)
		return error;
403
	raw_inode = ext4_raw_inode(&iloc);
404
	header = IHDR(inode, raw_inode);
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	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
	error = ext4_xattr_check_names(IFIRST(header), end);
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	if (error)
		goto cleanup;
409
	error = ext4_xattr_list_entries(dentry, IFIRST(header),
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					buffer, buffer_size);

cleanup:
	brelse(iloc.bh);
	return error;
}

/*
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 * ext4_xattr_list()
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 *
 * 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.
 */
427
static int
428
ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
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{
	int i_error, b_error;

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	down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
	i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
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	if (i_error < 0) {
		b_error = 0;
	} else {
		if (buffer) {
			buffer += i_error;
			buffer_size -= i_error;
		}
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		b_error = ext4_xattr_block_list(dentry, buffer, buffer_size);
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		if (b_error < 0)
			i_error = 0;
	}
445
	up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
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	return i_error + b_error;
}

/*
450
 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
451 452
 * not set, set it.
 */
453
static void ext4_xattr_update_super_block(handle_t *handle,
454 455
					  struct super_block *sb)
{
456
	if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
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		return;

459
	if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
460
		EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
461
		sb->s_dirt = 1;
462
		ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
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	}
}

/*
 * Release the xattr block BH: If the reference count is > 1, decrement
 * it; otherwise free the block.
 */
static void
471
ext4_xattr_release_block(handle_t *handle, struct inode *inode,
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			 struct buffer_head *bh)
{
	struct mb_cache_entry *ce = NULL;
475
	int error = 0;
476

477
	ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
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	error = ext4_journal_get_write_access(handle, bh);
	if (error)
		goto out;

	lock_buffer(bh);
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	if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
		ea_bdebug(bh, "refcount now=0; freeing");
		if (ce)
			mb_cache_entry_free(ce);
		get_bh(bh);
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		ext4_free_blocks(handle, inode, bh, 0, 1,
				 EXT4_FREE_BLOCKS_METADATA |
				 EXT4_FREE_BLOCKS_FORGET);
491
	} else {
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Marcin Slusarz 已提交
492
		le32_add_cpu(&BHDR(bh)->h_refcount, -1);
493
		error = ext4_handle_dirty_metadata(handle, inode, bh);
494
		if (IS_SYNC(inode))
495
			ext4_handle_sync(handle);
496
		dquot_free_block(inode, 1);
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		ea_bdebug(bh, "refcount now=%d; releasing",
			  le32_to_cpu(BHDR(bh)->h_refcount));
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		if (ce)
			mb_cache_entry_release(ce);
	}
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	unlock_buffer(bh);
out:
	ext4_std_error(inode->i_sb, error);
	return;
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}

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/*
 * Find the available free space for EAs. This also returns the total number of
 * bytes used by EA entries.
 */
static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
				    size_t *min_offs, void *base, int *total)
{
	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
		*total += EXT4_XATTR_LEN(last->e_name_len);
		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;
		}
	}
	return (*min_offs - ((void *)last - base) - sizeof(__u32));
}

526
struct ext4_xattr_info {
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	int name_index;
	const char *name;
	const void *value;
	size_t value_len;
};

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struct ext4_xattr_search {
	struct ext4_xattr_entry *first;
535 536
	void *base;
	void *end;
537
	struct ext4_xattr_entry *here;
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	int not_found;
};

static int
542
ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
543
{
544
	struct ext4_xattr_entry *last;
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	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);

	/* Compute min_offs and last. */
	last = s->first;
549
	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
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		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);
560
			free += EXT4_XATTR_SIZE(size);
561
		}
562
		free += EXT4_XATTR_LEN(name_len);
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	}
	if (i->value) {
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		if (free < EXT4_XATTR_SIZE(i->value_len) ||
		    free < EXT4_XATTR_LEN(name_len) +
			   EXT4_XATTR_SIZE(i->value_len))
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			return -ENOSPC;
	}

	if (i->value && s->not_found) {
		/* Insert the new name. */
573
		size_t size = EXT4_XATTR_LEN(name_len);
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		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;
585
			size_t size = EXT4_XATTR_SIZE(
586 587
				le32_to_cpu(s->here->e_value_size));

588
			if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
589 590 591 592
				/* The old and the new value have the same
				   size. Just replace. */
				s->here->e_value_size =
					cpu_to_le32(i->value_len);
593 594
				memset(val + size - EXT4_XATTR_PAD, 0,
				       EXT4_XATTR_PAD); /* Clear pad bytes. */
595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613
				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);
614
				last = EXT4_XATTR_NEXT(last);
615 616 617 618
			}
		}
		if (!i->value) {
			/* Remove the old name. */
619
			size_t size = EXT4_XATTR_LEN(name_len);
620 621 622 623 624 625 626 627 628 629 630
			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) {
631
			size_t size = EXT4_XATTR_SIZE(i->value_len);
632 633
			void *val = s->base + min_offs - size;
			s->here->e_value_offs = cpu_to_le16(min_offs - size);
634 635
			memset(val + size - EXT4_XATTR_PAD, 0,
			       EXT4_XATTR_PAD); /* Clear the pad bytes. */
636 637 638 639 640 641
			memcpy(val, i->value, i->value_len);
		}
	}
	return 0;
}

642 643
struct ext4_xattr_block_find {
	struct ext4_xattr_search s;
644 645 646 647
	struct buffer_head *bh;
};

static int
648 649
ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
		      struct ext4_xattr_block_find *bs)
650 651 652 653 654 655 656
{
	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);

657
	if (EXT4_I(inode)->i_file_acl) {
658
		/* The inode already has an extended attribute block. */
659
		bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
660 661 662 663 664 665
		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));
666
		if (ext4_xattr_check_block(bs->bh)) {
667 668
			EXT4_ERROR_INODE(inode, "bad block %llu",
					 EXT4_I(inode)->i_file_acl);
669 670 671 672 673 674 675 676
			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;
677
		error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
678 679 680 681 682 683 684 685 686 687 688 689
					      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
690 691 692
ext4_xattr_block_set(handle_t *handle, struct inode *inode,
		     struct ext4_xattr_info *i,
		     struct ext4_xattr_block_find *bs)
693 694 695
{
	struct super_block *sb = inode->i_sb;
	struct buffer_head *new_bh = NULL;
696
	struct ext4_xattr_search *s = &bs->s;
697
	struct mb_cache_entry *ce = NULL;
698
	int error = 0;
699

700
#define header(x) ((struct ext4_xattr_header *)(x))
701 702 703 704

	if (i->value && i->value_len > sb->s_blocksize)
		return -ENOSPC;
	if (s->base) {
705
		ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
706
					bs->bh->b_blocknr);
707 708 709 710 711
		error = ext4_journal_get_write_access(handle, bs->bh);
		if (error)
			goto cleanup;
		lock_buffer(bs->bh);

712 713 714 715 716 717
		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");
718
			error = ext4_xattr_set_entry(i, s);
719 720
			if (!error) {
				if (!IS_LAST_ENTRY(s->first))
721
					ext4_xattr_rehash(header(s->base),
722
							  s->here);
723
				ext4_xattr_cache_insert(bs->bh);
724 725 726 727 728
			}
			unlock_buffer(bs->bh);
			if (error == -EIO)
				goto bad_block;
			if (!error)
729 730 731
				error = ext4_handle_dirty_metadata(handle,
								   inode,
								   bs->bh);
732 733 734 735 736 737
			if (error)
				goto cleanup;
			goto inserted;
		} else {
			int offset = (char *)s->here - bs->bh->b_data;

738 739
			unlock_buffer(bs->bh);
			jbd2_journal_release_buffer(handle, bs->bh);
740 741 742 743 744
			if (ce) {
				mb_cache_entry_release(ce);
				ce = NULL;
			}
			ea_bdebug(bs->bh, "cloning");
745
			s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
746 747 748 749 750 751 752 753 754 755 756
			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. */
757
		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
758 759 760 761
		/* assert(header == s->base) */
		error = -ENOMEM;
		if (s->base == NULL)
			goto cleanup;
762
		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
763 764 765 766 767 768 769
		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;
	}

770
	error = ext4_xattr_set_entry(i, s);
771 772 773 774 775
	if (error == -EIO)
		goto bad_block;
	if (error)
		goto cleanup;
	if (!IS_LAST_ENTRY(s->first))
776
		ext4_xattr_rehash(header(s->base), s->here);
777 778 779

inserted:
	if (!IS_LAST_ENTRY(s->first)) {
780
		new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
781 782 783 784 785 786 787
		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. */
788 789
				error = dquot_alloc_block(inode, 1);
				if (error)
790
					goto cleanup;
791
				error = ext4_journal_get_write_access(handle,
792 793 794 795
								      new_bh);
				if (error)
					goto cleanup_dquot;
				lock_buffer(new_bh);
M
Marcin Slusarz 已提交
796
				le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
797 798 799
				ea_bdebug(new_bh, "reusing; refcount now=%d",
					le32_to_cpu(BHDR(new_bh)->h_refcount));
				unlock_buffer(new_bh);
800 801 802
				error = ext4_handle_dirty_metadata(handle,
								   inode,
								   new_bh);
803 804 805 806 807 808 809 810 811 812 813 814
				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 */
815 816 817
			ext4_fsblk_t goal, block;

			goal = ext4_group_first_block_no(sb,
818
						EXT4_I(inode)->i_block_group);
819 820

			/* non-extent files can't have physical blocks past 2^32 */
821
			if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
822 823 824
				goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;

			block = ext4_new_meta_blocks(handle, inode,
T
Theodore Ts'o 已提交
825
						  goal, NULL, &error);
826 827
			if (error)
				goto cleanup;
828

829
			if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
830 831
				BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);

832 833 834 835 836
			ea_idebug(inode, "creating block %d", block);

			new_bh = sb_getblk(sb, block);
			if (!new_bh) {
getblk_failed:
837 838
				ext4_free_blocks(handle, inode, 0, block, 1,
						 EXT4_FREE_BLOCKS_METADATA);
839 840 841 842
				error = -EIO;
				goto cleanup;
			}
			lock_buffer(new_bh);
843
			error = ext4_journal_get_create_access(handle, new_bh);
844 845 846 847 848 849 850
			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);
851
			ext4_xattr_cache_insert(new_bh);
852 853
			error = ext4_handle_dirty_metadata(handle,
							   inode, new_bh);
854 855 856 857 858 859
			if (error)
				goto cleanup;
		}
	}

	/* Update the inode. */
860
	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
861 862 863

	/* Drop the previous xattr block. */
	if (bs->bh && bs->bh != new_bh)
864
		ext4_xattr_release_block(handle, inode, bs->bh);
865 866 867 868 869 870 871 872 873 874 875 876
	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:
877
	dquot_free_block(inode, 1);
878 879 880
	goto cleanup;

bad_block:
881 882
	EXT4_ERROR_INODE(inode, "bad block %llu",
			 EXT4_I(inode)->i_file_acl);
883 884 885 886 887
	goto cleanup;

#undef header
}

888 889 890
struct ext4_xattr_ibody_find {
	struct ext4_xattr_search s;
	struct ext4_iloc iloc;
891 892 893
};

static int
894 895
ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
		      struct ext4_xattr_ibody_find *is)
896
{
897 898
	struct ext4_xattr_ibody_header *header;
	struct ext4_inode *raw_inode;
899 900
	int error;

901
	if (EXT4_I(inode)->i_extra_isize == 0)
902
		return 0;
903
	raw_inode = ext4_raw_inode(&is->iloc);
904 905 906
	header = IHDR(inode, raw_inode);
	is->s.base = is->s.first = IFIRST(header);
	is->s.here = is->s.first;
907
	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
908
	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
909
		error = ext4_xattr_check_names(IFIRST(header), is->s.end);
910 911 912
		if (error)
			return error;
		/* Find the named attribute. */
913
		error = ext4_xattr_find_entry(&is->s.here, i->name_index,
914 915 916 917 918 919 920 921 922 923
					      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
924 925 926
ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
		     struct ext4_xattr_info *i,
		     struct ext4_xattr_ibody_find *is)
927
{
928 929
	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_search *s = &is->s;
930 931
	int error;

932
	if (EXT4_I(inode)->i_extra_isize == 0)
933
		return -ENOSPC;
934
	error = ext4_xattr_set_entry(i, s);
935 936
	if (error)
		return error;
937
	header = IHDR(inode, ext4_raw_inode(&is->iloc));
938
	if (!IS_LAST_ENTRY(s->first)) {
939
		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
940
		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
941 942
	} else {
		header->h_magic = cpu_to_le32(0);
943
		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
944 945 946 947 948
	}
	return 0;
}

/*
949
 * ext4_xattr_set_handle()
950 951 952 953 954 955 956 957 958 959 960
 *
 * Create, replace or remove an extended attribute for this inode. Buffer
 * 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
961
ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
962 963 964
		      const char *name, const void *value, size_t value_len,
		      int flags)
{
965
	struct ext4_xattr_info i = {
966 967 968 969 970 971
		.name_index = name_index,
		.name = name,
		.value = value,
		.value_len = value_len,

	};
972
	struct ext4_xattr_ibody_find is = {
973 974
		.s = { .not_found = -ENODATA, },
	};
975
	struct ext4_xattr_block_find bs = {
976 977
		.s = { .not_found = -ENODATA, },
	};
K
Kalpak Shah 已提交
978
	unsigned long no_expand;
979 980 981 982 983 984
	int error;

	if (!name)
		return -EINVAL;
	if (strlen(name) > 255)
		return -ERANGE;
985
	down_write(&EXT4_I(inode)->xattr_sem);
986 987
	no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
K
Kalpak Shah 已提交
988

989
	error = ext4_get_inode_loc(inode, &is.iloc);
990 991 992
	if (error)
		goto cleanup;

993 994 995 996
	error = ext4_journal_get_write_access(handle, is.iloc.bh);
	if (error)
		goto cleanup;

997
	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
998 999
		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1000
		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1001 1002
	}

1003
	error = ext4_xattr_ibody_find(inode, &i, &is);
1004 1005 1006
	if (error)
		goto cleanup;
	if (is.s.not_found)
1007
		error = ext4_xattr_block_find(inode, &i, &bs);
1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
	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)
1024
			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1025
		else if (!bs.s.not_found)
1026
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1027
	} else {
1028
		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1029 1030
		if (!error && !bs.s.not_found) {
			i.value = NULL;
1031
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1032
		} else if (error == -ENOSPC) {
1033 1034 1035 1036 1037
			if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
				error = ext4_xattr_block_find(inode, &i, &bs);
				if (error)
					goto cleanup;
			}
1038
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1039 1040 1041 1042
			if (error)
				goto cleanup;
			if (!is.s.not_found) {
				i.value = NULL;
1043
				error = ext4_xattr_ibody_set(handle, inode, &i,
1044 1045 1046 1047 1048
							     &is);
			}
		}
	}
	if (!error) {
1049
		ext4_xattr_update_super_block(handle, inode->i_sb);
K
Kalpak Shah 已提交
1050
		inode->i_ctime = ext4_current_time(inode);
1051
		if (!value)
1052
			ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1053
		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1054
		/*
1055
		 * The bh is consumed by ext4_mark_iloc_dirty, even with
1056 1057 1058 1059
		 * error != 0.
		 */
		is.iloc.bh = NULL;
		if (IS_SYNC(inode))
1060
			ext4_handle_sync(handle);
1061 1062 1063 1064 1065
	}

cleanup:
	brelse(is.iloc.bh);
	brelse(bs.bh);
K
Kalpak Shah 已提交
1066
	if (no_expand == 0)
1067
		ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1068
	up_write(&EXT4_I(inode)->xattr_sem);
1069 1070 1071 1072
	return error;
}

/*
1073
 * ext4_xattr_set()
1074
 *
1075
 * Like ext4_xattr_set_handle, but start from an inode. This extended
1076 1077 1078 1079 1080
 * attribute modification is a filesystem transaction by itself.
 *
 * Returns 0, or a negative error number on failure.
 */
int
1081
ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1082 1083 1084 1085 1086 1087
	       const void *value, size_t value_len, int flags)
{
	handle_t *handle;
	int error, retries = 0;

retry:
1088
	handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1089 1090 1091 1092 1093
	if (IS_ERR(handle)) {
		error = PTR_ERR(handle);
	} else {
		int error2;

1094
		error = ext4_xattr_set_handle(handle, inode, name_index, name,
1095
					      value, value_len, flags);
1096
		error2 = ext4_journal_stop(handle);
1097
		if (error == -ENOSPC &&
1098
		    ext4_should_retry_alloc(inode->i_sb, &retries))
1099 1100 1101 1102 1103 1104 1105 1106
			goto retry;
		if (error == 0)
			error = error2;
	}

	return error;
}

1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148
/*
 * Shift the EA entries in the inode to create space for the increased
 * i_extra_isize.
 */
static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
				     int value_offs_shift, void *to,
				     void *from, size_t n, int blocksize)
{
	struct ext4_xattr_entry *last = entry;
	int new_offs;

	/* Adjust the value offsets of the entries */
	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
		if (!last->e_value_block && last->e_value_size) {
			new_offs = le16_to_cpu(last->e_value_offs) +
							value_offs_shift;
			BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
				 > blocksize);
			last->e_value_offs = cpu_to_le16(new_offs);
		}
	}
	/* Shift the entries by n bytes */
	memmove(to, from, n);
}

/*
 * Expand an inode by new_extra_isize bytes when EAs are present.
 * Returns 0 on success or negative error number on failure.
 */
int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
			       struct ext4_inode *raw_inode, handle_t *handle)
{
	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_entry *entry, *last, *first;
	struct buffer_head *bh = NULL;
	struct ext4_xattr_ibody_find *is = NULL;
	struct ext4_xattr_block_find *bs = NULL;
	char *buffer = NULL, *b_entry_name = NULL;
	size_t min_offs, free;
	int total_ino, total_blk;
	void *base, *start, *end;
	int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
A
Aneesh Kumar K.V 已提交
1149
	int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194

	down_write(&EXT4_I(inode)->xattr_sem);
retry:
	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
		up_write(&EXT4_I(inode)->xattr_sem);
		return 0;
	}

	header = IHDR(inode, raw_inode);
	entry = IFIRST(header);

	/*
	 * Check if enough free space is available in the inode to shift the
	 * entries ahead by new_extra_isize.
	 */

	base = start = entry;
	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
	min_offs = end - base;
	last = entry;
	total_ino = sizeof(struct ext4_xattr_ibody_header);

	free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
	if (free >= new_extra_isize) {
		entry = IFIRST(header);
		ext4_xattr_shift_entries(entry,	EXT4_I(inode)->i_extra_isize
				- new_extra_isize, (void *)raw_inode +
				EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
				(void *)header, total_ino,
				inode->i_sb->s_blocksize);
		EXT4_I(inode)->i_extra_isize = new_extra_isize;
		error = 0;
		goto cleanup;
	}

	/*
	 * Enough free space isn't available in the inode, check if
	 * EA block can hold new_extra_isize bytes.
	 */
	if (EXT4_I(inode)->i_file_acl) {
		bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
		error = -EIO;
		if (!bh)
			goto cleanup;
		if (ext4_xattr_check_block(bh)) {
1195 1196
			EXT4_ERROR_INODE(inode, "bad block %llu",
					 EXT4_I(inode)->i_file_acl);
1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300
			error = -EIO;
			goto cleanup;
		}
		base = BHDR(bh);
		first = BFIRST(bh);
		end = bh->b_data + bh->b_size;
		min_offs = end - base;
		free = ext4_xattr_free_space(first, &min_offs, base,
					     &total_blk);
		if (free < new_extra_isize) {
			if (!tried_min_extra_isize && s_min_extra_isize) {
				tried_min_extra_isize++;
				new_extra_isize = s_min_extra_isize;
				brelse(bh);
				goto retry;
			}
			error = -1;
			goto cleanup;
		}
	} else {
		free = inode->i_sb->s_blocksize;
	}

	while (new_extra_isize > 0) {
		size_t offs, size, entry_size;
		struct ext4_xattr_entry *small_entry = NULL;
		struct ext4_xattr_info i = {
			.value = NULL,
			.value_len = 0,
		};
		unsigned int total_size;  /* EA entry size + value size */
		unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
		unsigned int min_total_size = ~0U;

		is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
		bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
		if (!is || !bs) {
			error = -ENOMEM;
			goto cleanup;
		}

		is->s.not_found = -ENODATA;
		bs->s.not_found = -ENODATA;
		is->iloc.bh = NULL;
		bs->bh = NULL;

		last = IFIRST(header);
		/* Find the entry best suited to be pushed into EA block */
		entry = NULL;
		for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
			total_size =
			EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
					EXT4_XATTR_LEN(last->e_name_len);
			if (total_size <= free && total_size < min_total_size) {
				if (total_size < new_extra_isize) {
					small_entry = last;
				} else {
					entry = last;
					min_total_size = total_size;
				}
			}
		}

		if (entry == NULL) {
			if (small_entry) {
				entry = small_entry;
			} else {
				if (!tried_min_extra_isize &&
				    s_min_extra_isize) {
					tried_min_extra_isize++;
					new_extra_isize = s_min_extra_isize;
					goto retry;
				}
				error = -1;
				goto cleanup;
			}
		}
		offs = le16_to_cpu(entry->e_value_offs);
		size = le32_to_cpu(entry->e_value_size);
		entry_size = EXT4_XATTR_LEN(entry->e_name_len);
		i.name_index = entry->e_name_index,
		buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
		b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
		if (!buffer || !b_entry_name) {
			error = -ENOMEM;
			goto cleanup;
		}
		/* Save the entry name and the entry value */
		memcpy(buffer, (void *)IFIRST(header) + offs,
		       EXT4_XATTR_SIZE(size));
		memcpy(b_entry_name, entry->e_name, entry->e_name_len);
		b_entry_name[entry->e_name_len] = '\0';
		i.name = b_entry_name;

		error = ext4_get_inode_loc(inode, &is->iloc);
		if (error)
			goto cleanup;

		error = ext4_xattr_ibody_find(inode, &i, is);
		if (error)
			goto cleanup;

		/* Remove the chosen entry from the inode */
		error = ext4_xattr_ibody_set(handle, inode, &i, is);
1301 1302
		if (error)
			goto cleanup;
1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321

		entry = IFIRST(header);
		if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
			shift_bytes = new_extra_isize;
		else
			shift_bytes = entry_size + size;
		/* Adjust the offsets and shift the remaining entries ahead */
		ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
			shift_bytes, (void *)raw_inode +
			EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
			(void *)header, total_ino - entry_size,
			inode->i_sb->s_blocksize);

		extra_isize += shift_bytes;
		new_extra_isize -= shift_bytes;
		EXT4_I(inode)->i_extra_isize = extra_isize;

		i.name = b_entry_name;
		i.value = buffer;
A
Aneesh Kumar K.V 已提交
1322
		i.value_len = size;
1323 1324 1325 1326 1327 1328 1329 1330 1331 1332
		error = ext4_xattr_block_find(inode, &i, bs);
		if (error)
			goto cleanup;

		/* Add entry which was removed from the inode into the block */
		error = ext4_xattr_block_set(handle, inode, &i, bs);
		if (error)
			goto cleanup;
		kfree(b_entry_name);
		kfree(buffer);
1333 1334
		b_entry_name = NULL;
		buffer = NULL;
1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356
		brelse(is->iloc.bh);
		kfree(is);
		kfree(bs);
	}
	brelse(bh);
	up_write(&EXT4_I(inode)->xattr_sem);
	return 0;

cleanup:
	kfree(b_entry_name);
	kfree(buffer);
	if (is)
		brelse(is->iloc.bh);
	kfree(is);
	kfree(bs);
	brelse(bh);
	up_write(&EXT4_I(inode)->xattr_sem);
	return error;
}



1357
/*
1358
 * ext4_xattr_delete_inode()
1359 1360 1361 1362 1363 1364
 *
 * 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
1365
ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1366 1367 1368
{
	struct buffer_head *bh = NULL;

1369
	if (!EXT4_I(inode)->i_file_acl)
1370
		goto cleanup;
1371
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1372
	if (!bh) {
1373 1374
		EXT4_ERROR_INODE(inode, "block %llu read error",
				 EXT4_I(inode)->i_file_acl);
1375 1376
		goto cleanup;
	}
1377
	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1378
	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1379 1380
		EXT4_ERROR_INODE(inode, "bad block %llu",
				 EXT4_I(inode)->i_file_acl);
1381 1382
		goto cleanup;
	}
1383 1384
	ext4_xattr_release_block(handle, inode, bh);
	EXT4_I(inode)->i_file_acl = 0;
1385 1386 1387 1388 1389 1390

cleanup:
	brelse(bh);
}

/*
1391
 * ext4_xattr_put_super()
1392 1393 1394 1395
 *
 * This is called when a file system is unmounted.
 */
void
1396
ext4_xattr_put_super(struct super_block *sb)
1397 1398 1399 1400 1401
{
	mb_cache_shrink(sb->s_bdev);
}

/*
1402
 * ext4_xattr_cache_insert()
1403 1404 1405 1406 1407 1408 1409
 *
 * 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
1410
ext4_xattr_cache_insert(struct buffer_head *bh)
1411 1412 1413 1414 1415
{
	__u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
	struct mb_cache_entry *ce;
	int error;

1416
	ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434
	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);
	}
}

/*
1435
 * ext4_xattr_cmp()
1436 1437 1438 1439 1440 1441 1442
 *
 * 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
1443 1444
ext4_xattr_cmp(struct ext4_xattr_header *header1,
	       struct ext4_xattr_header *header2)
1445
{
1446
	struct ext4_xattr_entry *entry1, *entry2;
1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465

	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;

1466 1467
		entry1 = EXT4_XATTR_NEXT(entry1);
		entry2 = EXT4_XATTR_NEXT(entry2);
1468 1469 1470 1471 1472 1473 1474
	}
	if (!IS_LAST_ENTRY(entry2))
		return 1;
	return 0;
}

/*
1475
 * ext4_xattr_cache_find()
1476 1477 1478 1479 1480 1481 1482
 *
 * 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 *
1483
ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1484 1485 1486 1487 1488 1489 1490 1491 1492
		      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:
1493
	ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504
				       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) {
1505 1506
			EXT4_ERROR_INODE(inode, "block %lu read error",
					 (unsigned long) ce->e_block);
1507
		} else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1508
				EXT4_XATTR_REFCOUNT_MAX) {
1509 1510 1511
			ea_idebug(inode, "block %lu refcount %d>=%d",
				  (unsigned long) ce->e_block,
				  le32_to_cpu(BHDR(bh)->h_refcount),
1512 1513
					  EXT4_XATTR_REFCOUNT_MAX);
		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526
			*pce = ce;
			return bh;
		}
		brelse(bh);
		ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
	}
	return NULL;
}

#define NAME_HASH_SHIFT 5
#define VALUE_HASH_SHIFT 16

/*
1527
 * ext4_xattr_hash_entry()
1528 1529 1530
 *
 * Compute the hash of an extended attribute.
 */
1531 1532
static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
					 struct ext4_xattr_entry *entry)
1533 1534 1535 1536 1537
{
	__u32 hash = 0;
	char *name = entry->e_name;
	int n;

1538
	for (n = 0; n < entry->e_name_len; n++) {
1539 1540 1541 1542 1543 1544 1545 1546 1547
		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) +
1548
		     EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562
			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

/*
1563
 * ext4_xattr_rehash()
1564 1565 1566
 *
 * Re-compute the extended attribute hash value after an entry has changed.
 */
1567 1568
static void ext4_xattr_rehash(struct ext4_xattr_header *header,
			      struct ext4_xattr_entry *entry)
1569
{
1570
	struct ext4_xattr_entry *here;
1571 1572
	__u32 hash = 0;

1573
	ext4_xattr_hash_entry(header, entry);
1574 1575 1576 1577 1578 1579 1580 1581 1582 1583
	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);
1584
		here = EXT4_XATTR_NEXT(here);
1585 1586 1587 1588 1589 1590 1591
	}
	header->h_hash = cpu_to_le32(hash);
}

#undef BLOCK_HASH_SHIFT

int __init
1592
init_ext4_xattr(void)
1593
{
1594
	ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1595 1596
		sizeof(struct mb_cache_entry) +
		sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1597
	if (!ext4_xattr_cache)
1598 1599 1600 1601 1602
		return -ENOMEM;
	return 0;
}

void
1603
exit_ext4_xattr(void)
1604
{
1605 1606 1607
	if (ext4_xattr_cache)
		mb_cache_destroy(ext4_xattr_cache);
	ext4_xattr_cache = NULL;
1608
}