xattr.c 48.2 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
 * ----------------
46
 * 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>
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#include <linux/mbcache.h>
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#include <linux/quotaops.h>
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#include "ext4_jbd2.h"
#include "ext4.h"
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#include "xattr.h"
#include "acl.h"

63
#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 { \
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		printk(KERN_DEBUG "block %pg:%lu: ",		   \
		       bh->b_bdev, (unsigned long) bh->b_blocknr); \
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		printk(f); \
		printk("\n"); \
	} while (0)
#else
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# define ea_idebug(inode, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
# define ea_bdebug(bh, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
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#endif

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static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
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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,
88
			   size_t buffer_size);
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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]  = &posix_acl_access_xattr_handler,
	[EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
95
#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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	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_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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#define EXT4_GET_MB_CACHE(inode)	(((struct ext4_sb_info *) \
				inode->i_sb->s_fs_info)->s_mb_cache)

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static __le32 ext4_xattr_block_csum(struct inode *inode,
				    sector_t block_nr,
				    struct ext4_xattr_header *hdr)
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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	__u32 csum;
	__le64 dsk_block_nr = cpu_to_le64(block_nr);
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	__u32 dummy_csum = 0;
	int offset = offsetof(struct ext4_xattr_header, h_checksum);
127

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	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
			   sizeof(dsk_block_nr));
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	csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
	offset += sizeof(dummy_csum);
	csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
			   EXT4_BLOCK_SIZE(inode->i_sb) - offset);
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	return cpu_to_le32(csum);
}

static int ext4_xattr_block_csum_verify(struct inode *inode,
					sector_t block_nr,
					struct ext4_xattr_header *hdr)
{
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	if (ext4_has_metadata_csum(inode->i_sb) &&
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	    (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
		return 0;
	return 1;
}

static void ext4_xattr_block_csum_set(struct inode *inode,
				      sector_t block_nr,
				      struct ext4_xattr_header *hdr)
{
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	if (!ext4_has_metadata_csum(inode->i_sb))
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		return;

	hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
}

static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
						struct inode *inode,
						struct buffer_head *bh)
{
	ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
	return ext4_handle_dirty_metadata(handle, inode, bh);
}

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static inline const struct xattr_handler *
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ext4_xattr_handler(int name_index)
169
{
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	const struct xattr_handler *handler = NULL;
171

172 173
	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()
 *
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 * d_inode(dentry)->i_mutex: don't care
181 182
 */
ssize_t
183
ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
184
{
185
	return ext4_xattr_list(dentry, buffer, size);
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}

static int
189 190
ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
		       void *value_start)
191
{
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	struct ext4_xattr_entry *e = entry;

	while (!IS_LAST_ENTRY(e)) {
		struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
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		if ((void *)next >= end)
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			return -EFSCORRUPTED;
198
		e = next;
199
	}
200 201

	while (!IS_LAST_ENTRY(entry)) {
202 203
		if (entry->e_value_block != 0)
			return -EFSCORRUPTED;
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		if (entry->e_value_size != 0 &&
		    (value_start + le16_to_cpu(entry->e_value_offs) <
		     (void *)e + sizeof(__u32) ||
		     value_start + le16_to_cpu(entry->e_value_offs) +
		    le32_to_cpu(entry->e_value_size) > end))
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			return -EFSCORRUPTED;
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		entry = EXT4_XATTR_NEXT(entry);
	}

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	return 0;
}

static inline int
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ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
218
{
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	int error;

	if (buffer_verified(bh))
		return 0;

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	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
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	    BHDR(bh)->h_blocks != cpu_to_le32(1))
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		return -EFSCORRUPTED;
227
	if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
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		return -EFSBADCRC;
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	error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
				       bh->b_data);
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	if (!error)
		set_buffer_verified(bh);
	return error;
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}

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static int
__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
			 void *end, const char *function, unsigned int line)
{
	struct ext4_xattr_entry *entry = IFIRST(header);
	int error = -EFSCORRUPTED;

	if (((void *) header >= end) ||
	    (header->h_magic != le32_to_cpu(EXT4_XATTR_MAGIC)))
		goto errout;
	error = ext4_xattr_check_names(entry, end, entry);
errout:
	if (error)
		__ext4_error_inode(inode, function, line, 0,
				   "corrupted in-inode xattr");
	return error;
}

#define xattr_check_inode(inode, header, end) \
	__xattr_check_inode((inode), (header), (end), __func__, __LINE__)

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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)
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		return -EFSCORRUPTED;
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	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 -EFSCORRUPTED;
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	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;
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	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
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	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 %llu",
		  (unsigned long long)EXT4_I(inode)->i_file_acl);
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	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(inode, bh)) {
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bad_block:
320 321
		EXT4_ERROR_INODE(inode, "bad block %llu",
				 EXT4_I(inode)->i_file_acl);
322
		error = -EFSCORRUPTED;
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		goto cleanup;
	}
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	ext4_xattr_cache_insert(ext4_mb_cache, 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 == -EFSCORRUPTED)
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		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;
}

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int
348
ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
349 350
		     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;
355 356 357 358
	size_t size;
	void *end;
	int error;

359
	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
360
		return -ENODATA;
361
	error = ext4_get_inode_loc(inode, &iloc);
362 363
	if (error)
		return error;
364
	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;
368
	error = xattr_check_inode(inode, header, 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;
}

/*
391
 * ext4_xattr_get()
392 393 394 395 396 397 398 399 400
 *
 * 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
401
ext4_xattr_get(struct inode *inode, int name_index, const char *name,
402 403 404 405
	       void *buffer, size_t buffer_size)
{
	int error;

406 407 408
	if (strlen(name) > 255)
		return -ERANGE;

409 410
	down_read(&EXT4_I(inode)->xattr_sem);
	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
411 412
				     buffer_size);
	if (error == -ENODATA)
413
		error = ext4_xattr_block_get(inode, name_index, name, buffer,
414
					     buffer_size);
415
	up_read(&EXT4_I(inode)->xattr_sem);
416 417 418 419
	return error;
}

static int
420
ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
421 422 423 424
			char *buffer, size_t buffer_size)
{
	size_t rest = buffer_size;

425
	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
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		const struct xattr_handler *handler =
427
			ext4_xattr_handler(entry->e_name_index);
428

429 430 431 432 433
		if (handler && (!handler->list || handler->list(dentry))) {
			const char *prefix = handler->prefix ?: handler->name;
			size_t prefix_len = strlen(prefix);
			size_t size = prefix_len + entry->e_name_len + 1;

434 435 436
			if (buffer) {
				if (size > rest)
					return -ERANGE;
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				memcpy(buffer, prefix, prefix_len);
				buffer += prefix_len;
				memcpy(buffer, entry->e_name, entry->e_name_len);
				buffer += entry->e_name_len;
				*buffer++ = 0;
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			}
			rest -= size;
		}
	}
446
	return buffer_size - rest;  /* total size */
447 448 449
}

static int
450
ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
451
{
452
	struct inode *inode = d_inode(dentry);
453 454
	struct buffer_head *bh = NULL;
	int error;
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	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
456 457 458 459 460

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

	error = 0;
461
	if (!EXT4_I(inode)->i_file_acl)
462
		goto cleanup;
463 464
	ea_idebug(inode, "reading block %llu",
		  (unsigned long long)EXT4_I(inode)->i_file_acl);
465
	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));
471
	if (ext4_xattr_check_block(inode, bh)) {
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		EXT4_ERROR_INODE(inode, "bad block %llu",
				 EXT4_I(inode)->i_file_acl);
474
		error = -EFSCORRUPTED;
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		goto cleanup;
	}
477
	ext4_xattr_cache_insert(ext4_mb_cache, bh);
478
	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
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cleanup:
	brelse(bh);

	return error;
}

static int
487
ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
488
{
489
	struct inode *inode = d_inode(dentry);
490 491 492
	struct ext4_xattr_ibody_header *header;
	struct ext4_inode *raw_inode;
	struct ext4_iloc iloc;
493 494 495
	void *end;
	int error;

496
	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
497
		return 0;
498
	error = ext4_get_inode_loc(inode, &iloc);
499 500
	if (error)
		return error;
501
	raw_inode = ext4_raw_inode(&iloc);
502
	header = IHDR(inode, raw_inode);
503
	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
504
	error = xattr_check_inode(inode, header, end);
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	if (error)
		goto cleanup;
507
	error = ext4_xattr_list_entries(dentry, IFIRST(header),
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					buffer, buffer_size);

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

/*
516
 * ext4_xattr_list()
517 518 519 520 521 522 523 524
 *
 * 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.
 */
525
static int
526
ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
527
{
528
	int ret, ret2;
529

530
	down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
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	ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
	if (ret < 0)
		goto errout;
	if (buffer) {
		buffer += ret;
		buffer_size -= ret;
537
	}
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	ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
	if (ret < 0)
		goto errout;
	ret += ret2;
errout:
543
	up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
544
	return ret;
545 546 547
}

/*
548
 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
549 550
 * not set, set it.
 */
551
static void ext4_xattr_update_super_block(handle_t *handle,
552 553
					  struct super_block *sb)
{
554
	if (ext4_has_feature_xattr(sb))
555 556
		return;

557
	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
558
	if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
559
		ext4_set_feature_xattr(sb);
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		ext4_handle_dirty_super(handle, sb);
561 562 563 564
	}
}

/*
565 566
 * Release the xattr block BH: If the reference count is > 1, decrement it;
 * otherwise free the block.
567 568
 */
static void
569
ext4_xattr_release_block(handle_t *handle, struct inode *inode,
570 571
			 struct buffer_head *bh)
{
572 573
	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
	u32 hash, ref;
574
	int error = 0;
575

576
	BUFFER_TRACE(bh, "get_write_access");
577 578 579 580 581
	error = ext4_journal_get_write_access(handle, bh);
	if (error)
		goto out;

	lock_buffer(bh);
582 583 584
	hash = le32_to_cpu(BHDR(bh)->h_hash);
	ref = le32_to_cpu(BHDR(bh)->h_refcount);
	if (ref == 1) {
585
		ea_bdebug(bh, "refcount now=0; freeing");
J
Jan Kara 已提交
586 587 588 589
		/*
		 * This must happen under buffer lock for
		 * ext4_xattr_block_set() to reliably detect freed block
		 */
590
		mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
591
		get_bh(bh);
592
		unlock_buffer(bh);
593 594 595
		ext4_free_blocks(handle, inode, bh, 0, 1,
				 EXT4_FREE_BLOCKS_METADATA |
				 EXT4_FREE_BLOCKS_FORGET);
596
	} else {
597 598 599 600 601 602 603 604 605 606 607 608 609
		ref--;
		BHDR(bh)->h_refcount = cpu_to_le32(ref);
		if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
			struct mb_cache_entry *ce;

			ce = mb_cache_entry_get(ext4_mb_cache, hash,
						bh->b_blocknr);
			if (ce) {
				ce->e_reusable = 1;
				mb_cache_entry_put(ext4_mb_cache, ce);
			}
		}

610 611 612 613 614 615 616 617 618 619 620 621 622
		/*
		 * Beware of this ugliness: Releasing of xattr block references
		 * from different inodes can race and so we have to protect
		 * from a race where someone else frees the block (and releases
		 * its journal_head) before we are done dirtying the buffer. In
		 * nojournal mode this race is harmless and we actually cannot
		 * call ext4_handle_dirty_xattr_block() with locked buffer as
		 * that function can call sync_dirty_buffer() so for that case
		 * we handle the dirtying after unlocking the buffer.
		 */
		if (ext4_handle_valid(handle))
			error = ext4_handle_dirty_xattr_block(handle, inode,
							      bh);
623
		unlock_buffer(bh);
624 625 626
		if (!ext4_handle_valid(handle))
			error = ext4_handle_dirty_xattr_block(handle, inode,
							      bh);
627
		if (IS_SYNC(inode))
628
			ext4_handle_sync(handle);
629
		dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
630 631
		ea_bdebug(bh, "refcount now=%d; releasing",
			  le32_to_cpu(BHDR(bh)->h_refcount));
632
	}
633 634 635
out:
	ext4_std_error(inode->i_sb, error);
	return;
636 637
}

638 639 640 641 642 643 644 645 646 647 648 649 650
/*
 * 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)) {
		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;
		}
651 652
		if (total)
			*total += EXT4_XATTR_LEN(last->e_name_len);
653 654 655 656
	}
	return (*min_offs - ((void *)last - base) - sizeof(__u32));
}

657
static int
658
ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
659
{
660
	struct ext4_xattr_entry *last;
661 662 663 664
	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);

	/* Compute min_offs and last. */
	last = s->first;
665
	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
666 667 668 669 670 671 672 673 674 675
		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);
676
			free += EXT4_XATTR_SIZE(size);
677
		}
678
		free += EXT4_XATTR_LEN(name_len);
679 680
	}
	if (i->value) {
681
		if (free < EXT4_XATTR_LEN(name_len) +
682
			   EXT4_XATTR_SIZE(i->value_len))
683 684 685 686 687
			return -ENOSPC;
	}

	if (i->value && s->not_found) {
		/* Insert the new name. */
688
		size_t size = EXT4_XATTR_LEN(name_len);
689 690 691 692 693 694 695 696 697 698 699
		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;
700
			size_t size = EXT4_XATTR_SIZE(
701 702
				le32_to_cpu(s->here->e_value_size));

703
			if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
704 705 706 707
				/* The old and the new value have the same
				   size. Just replace. */
				s->here->e_value_size =
					cpu_to_le32(i->value_len);
708 709 710 711 712 713 714 715
				if (i->value == EXT4_ZERO_XATTR_VALUE) {
					memset(val, 0, size);
				} else {
					/* Clear pad bytes first. */
					memset(val + size - EXT4_XATTR_PAD, 0,
					       EXT4_XATTR_PAD);
					memcpy(val, i->value, i->value_len);
				}
716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733
				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);
734
				last = EXT4_XATTR_NEXT(last);
735 736 737 738
			}
		}
		if (!i->value) {
			/* Remove the old name. */
739
			size_t size = EXT4_XATTR_LEN(name_len);
740 741 742 743 744 745 746 747 748 749 750
			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) {
751
			size_t size = EXT4_XATTR_SIZE(i->value_len);
752 753
			void *val = s->base + min_offs - size;
			s->here->e_value_offs = cpu_to_le16(min_offs - size);
754 755 756 757 758 759 760 761
			if (i->value == EXT4_ZERO_XATTR_VALUE) {
				memset(val, 0, size);
			} else {
				/* Clear the pad bytes first. */
				memset(val + size - EXT4_XATTR_PAD, 0,
				       EXT4_XATTR_PAD);
				memcpy(val, i->value, i->value_len);
			}
762 763 764 765 766
		}
	}
	return 0;
}

767 768
struct ext4_xattr_block_find {
	struct ext4_xattr_search s;
769 770 771 772
	struct buffer_head *bh;
};

static int
773 774
ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
		      struct ext4_xattr_block_find *bs)
775 776 777 778 779 780 781
{
	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);

782
	if (EXT4_I(inode)->i_file_acl) {
783
		/* The inode already has an extended attribute block. */
784
		bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
785 786 787 788 789 790
		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));
791
		if (ext4_xattr_check_block(inode, bs->bh)) {
792 793
			EXT4_ERROR_INODE(inode, "bad block %llu",
					 EXT4_I(inode)->i_file_acl);
794
			error = -EFSCORRUPTED;
795 796 797 798 799 800 801
			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;
802
		error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
803 804 805 806 807 808 809 810 811 812 813 814
					      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
815 816 817
ext4_xattr_block_set(handle_t *handle, struct inode *inode,
		     struct ext4_xattr_info *i,
		     struct ext4_xattr_block_find *bs)
818 819 820
{
	struct super_block *sb = inode->i_sb;
	struct buffer_head *new_bh = NULL;
821
	struct ext4_xattr_search *s = &bs->s;
J
Jan Kara 已提交
822
	struct mb_cache_entry *ce = NULL;
823
	int error = 0;
J
Jan Kara 已提交
824
	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
825

826
#define header(x) ((struct ext4_xattr_header *)(x))
827 828 829 830

	if (i->value && i->value_len > sb->s_blocksize)
		return -ENOSPC;
	if (s->base) {
831
		BUFFER_TRACE(bs->bh, "get_write_access");
832 833 834 835 836
		error = ext4_journal_get_write_access(handle, bs->bh);
		if (error)
			goto cleanup;
		lock_buffer(bs->bh);

837
		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
J
Jan Kara 已提交
838 839 840 841 842 843 844
			__u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);

			/*
			 * This must happen under buffer lock for
			 * ext4_xattr_block_set() to reliably detect modified
			 * block
			 */
J
Jan Kara 已提交
845 846
			mb_cache_entry_delete_block(ext4_mb_cache, hash,
						    bs->bh->b_blocknr);
847
			ea_bdebug(bs->bh, "modifying in-place");
848
			error = ext4_xattr_set_entry(i, s);
849 850
			if (!error) {
				if (!IS_LAST_ENTRY(s->first))
851
					ext4_xattr_rehash(header(s->base),
852
							  s->here);
853 854
				ext4_xattr_cache_insert(ext4_mb_cache,
					bs->bh);
855 856
			}
			unlock_buffer(bs->bh);
857
			if (error == -EFSCORRUPTED)
858 859
				goto bad_block;
			if (!error)
860 861 862
				error = ext4_handle_dirty_xattr_block(handle,
								      inode,
								      bs->bh);
863 864 865 866 867 868
			if (error)
				goto cleanup;
			goto inserted;
		} else {
			int offset = (char *)s->here - bs->bh->b_data;

869
			unlock_buffer(bs->bh);
870
			ea_bdebug(bs->bh, "cloning");
871
			s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
872 873 874 875 876 877 878 879 880 881 882
			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. */
883
		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
884 885 886 887
		/* assert(header == s->base) */
		error = -ENOMEM;
		if (s->base == NULL)
			goto cleanup;
888
		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
889 890 891 892 893 894 895
		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;
	}

896
	error = ext4_xattr_set_entry(i, s);
897
	if (error == -EFSCORRUPTED)
898 899 900 901
		goto bad_block;
	if (error)
		goto cleanup;
	if (!IS_LAST_ENTRY(s->first))
902
		ext4_xattr_rehash(header(s->base), s->here);
903 904 905

inserted:
	if (!IS_LAST_ENTRY(s->first)) {
906
		new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
907 908 909 910 911
		if (new_bh) {
			/* We found an identical block in the cache. */
			if (new_bh == bs->bh)
				ea_bdebug(new_bh, "keeping");
			else {
912 913
				u32 ref;

914 915
				/* The old block is released after updating
				   the inode. */
916 917
				error = dquot_alloc_block(inode,
						EXT4_C2B(EXT4_SB(sb), 1));
918
				if (error)
919
					goto cleanup;
920
				BUFFER_TRACE(new_bh, "get_write_access");
921
				error = ext4_journal_get_write_access(handle,
922 923 924 925
								      new_bh);
				if (error)
					goto cleanup_dquot;
				lock_buffer(new_bh);
J
Jan Kara 已提交
926 927
				/*
				 * We have to be careful about races with
928 929 930 931 932 933 934 935 936
				 * freeing, rehashing or adding references to
				 * xattr block. Once we hold buffer lock xattr
				 * block's state is stable so we can check
				 * whether the block got freed / rehashed or
				 * not.  Since we unhash mbcache entry under
				 * buffer lock when freeing / rehashing xattr
				 * block, checking whether entry is still
				 * hashed is reliable. Same rules hold for
				 * e_reusable handling.
J
Jan Kara 已提交
937
				 */
938 939
				if (hlist_bl_unhashed(&ce->e_hash_list) ||
				    !ce->e_reusable) {
J
Jan Kara 已提交
940 941 942 943 944 945 946 947 948
					/*
					 * Undo everything and check mbcache
					 * again.
					 */
					unlock_buffer(new_bh);
					dquot_free_block(inode,
							 EXT4_C2B(EXT4_SB(sb),
								  1));
					brelse(new_bh);
J
Jan Kara 已提交
949
					mb_cache_entry_put(ext4_mb_cache, ce);
J
Jan Kara 已提交
950 951 952 953
					ce = NULL;
					new_bh = NULL;
					goto inserted;
				}
954 955 956 957
				ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
				BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
				if (ref >= EXT4_XATTR_REFCOUNT_MAX)
					ce->e_reusable = 0;
958
				ea_bdebug(new_bh, "reusing; refcount now=%d",
959
					  ref);
960
				unlock_buffer(new_bh);
961 962 963
				error = ext4_handle_dirty_xattr_block(handle,
								      inode,
								      new_bh);
964 965 966
				if (error)
					goto cleanup_dquot;
			}
J
Jan Kara 已提交
967 968
			mb_cache_entry_touch(ext4_mb_cache, ce);
			mb_cache_entry_put(ext4_mb_cache, ce);
969 970 971 972 973 974 975 976
			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 */
977 978 979
			ext4_fsblk_t goal, block;

			goal = ext4_group_first_block_no(sb,
980
						EXT4_I(inode)->i_block_group);
981 982

			/* non-extent files can't have physical blocks past 2^32 */
983
			if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
984 985
				goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;

986 987
			block = ext4_new_meta_blocks(handle, inode, goal, 0,
						     NULL, &error);
988 989
			if (error)
				goto cleanup;
990

991
			if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
992 993
				BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);

994 995
			ea_idebug(inode, "creating block %llu",
				  (unsigned long long)block);
996 997

			new_bh = sb_getblk(sb, block);
998
			if (unlikely(!new_bh)) {
999
				error = -ENOMEM;
1000
getblk_failed:
1001
				ext4_free_blocks(handle, inode, NULL, block, 1,
1002
						 EXT4_FREE_BLOCKS_METADATA);
1003 1004 1005
				goto cleanup;
			}
			lock_buffer(new_bh);
1006
			error = ext4_journal_get_create_access(handle, new_bh);
1007 1008
			if (error) {
				unlock_buffer(new_bh);
1009
				error = -EIO;
1010 1011 1012 1013 1014
				goto getblk_failed;
			}
			memcpy(new_bh->b_data, s->base, new_bh->b_size);
			set_buffer_uptodate(new_bh);
			unlock_buffer(new_bh);
1015
			ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1016 1017
			error = ext4_handle_dirty_xattr_block(handle,
							      inode, new_bh);
1018 1019 1020 1021 1022 1023
			if (error)
				goto cleanup;
		}
	}

	/* Update the inode. */
1024
	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1025 1026 1027

	/* Drop the previous xattr block. */
	if (bs->bh && bs->bh != new_bh)
1028
		ext4_xattr_release_block(handle, inode, bs->bh);
1029 1030 1031 1032
	error = 0;

cleanup:
	if (ce)
J
Jan Kara 已提交
1033
		mb_cache_entry_put(ext4_mb_cache, ce);
1034 1035 1036 1037 1038 1039 1040
	brelse(new_bh);
	if (!(bs->bh && s->base == bs->bh->b_data))
		kfree(s->base);

	return error;

cleanup_dquot:
1041
	dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1042 1043 1044
	goto cleanup;

bad_block:
1045 1046
	EXT4_ERROR_INODE(inode, "bad block %llu",
			 EXT4_I(inode)->i_file_acl);
1047 1048 1049 1050 1051
	goto cleanup;

#undef header
}

T
Tao Ma 已提交
1052 1053
int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
			  struct ext4_xattr_ibody_find *is)
1054
{
1055 1056
	struct ext4_xattr_ibody_header *header;
	struct ext4_inode *raw_inode;
1057 1058
	int error;

1059
	if (EXT4_I(inode)->i_extra_isize == 0)
1060
		return 0;
1061
	raw_inode = ext4_raw_inode(&is->iloc);
1062 1063 1064
	header = IHDR(inode, raw_inode);
	is->s.base = is->s.first = IFIRST(header);
	is->s.here = is->s.first;
1065
	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1066
	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1067
		error = xattr_check_inode(inode, header, is->s.end);
1068 1069 1070
		if (error)
			return error;
		/* Find the named attribute. */
1071
		error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1072 1073 1074 1075 1076 1077 1078 1079 1080
					      i->name, is->s.end -
					      (void *)is->s.base, 0);
		if (error && error != -ENODATA)
			return error;
		is->s.not_found = error;
	}
	return 0;
}

1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121
int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
				struct ext4_xattr_info *i,
				struct ext4_xattr_ibody_find *is)
{
	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_search *s = &is->s;
	int error;

	if (EXT4_I(inode)->i_extra_isize == 0)
		return -ENOSPC;
	error = ext4_xattr_set_entry(i, s);
	if (error) {
		if (error == -ENOSPC &&
		    ext4_has_inline_data(inode)) {
			error = ext4_try_to_evict_inline_data(handle, inode,
					EXT4_XATTR_LEN(strlen(i->name) +
					EXT4_XATTR_SIZE(i->value_len)));
			if (error)
				return error;
			error = ext4_xattr_ibody_find(inode, i, is);
			if (error)
				return error;
			error = ext4_xattr_set_entry(i, s);
		}
		if (error)
			return error;
	}
	header = IHDR(inode, ext4_raw_inode(&is->iloc));
	if (!IS_LAST_ENTRY(s->first)) {
		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
	} else {
		header->h_magic = cpu_to_le32(0);
		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
	}
	return 0;
}

static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
				struct ext4_xattr_info *i,
				struct ext4_xattr_ibody_find *is)
1122
{
1123 1124
	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_search *s = &is->s;
1125 1126
	int error;

1127
	if (EXT4_I(inode)->i_extra_isize == 0)
1128
		return -ENOSPC;
1129
	error = ext4_xattr_set_entry(i, s);
1130 1131
	if (error)
		return error;
1132
	header = IHDR(inode, ext4_raw_inode(&is->iloc));
1133
	if (!IS_LAST_ENTRY(s->first)) {
1134
		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1135
		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1136 1137
	} else {
		header->h_magic = cpu_to_le32(0);
1138
		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1139 1140 1141 1142
	}
	return 0;
}

1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153
static int ext4_xattr_value_same(struct ext4_xattr_search *s,
				 struct ext4_xattr_info *i)
{
	void *value;

	if (le32_to_cpu(s->here->e_value_size) != i->value_len)
		return 0;
	value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
	return !memcmp(value, i->value, i->value_len);
}

1154
/*
1155
 * ext4_xattr_set_handle()
1156
 *
1157
 * Create, replace or remove an extended attribute for this inode.  Value
1158 1159 1160 1161 1162 1163 1164 1165 1166
 * 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
1167
ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1168 1169 1170
		      const char *name, const void *value, size_t value_len,
		      int flags)
{
1171
	struct ext4_xattr_info i = {
1172 1173 1174 1175 1176 1177
		.name_index = name_index,
		.name = name,
		.value = value,
		.value_len = value_len,

	};
1178
	struct ext4_xattr_ibody_find is = {
1179 1180
		.s = { .not_found = -ENODATA, },
	};
1181
	struct ext4_xattr_block_find bs = {
1182 1183
		.s = { .not_found = -ENODATA, },
	};
K
Kalpak Shah 已提交
1184
	unsigned long no_expand;
1185 1186 1187 1188 1189 1190
	int error;

	if (!name)
		return -EINVAL;
	if (strlen(name) > 255)
		return -ERANGE;
1191
	down_write(&EXT4_I(inode)->xattr_sem);
1192 1193
	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
1194

1195
	error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1196 1197 1198
	if (error)
		goto cleanup;

1199
	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1200 1201
		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1202
		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1203 1204
	}

1205
	error = ext4_xattr_ibody_find(inode, &i, &is);
1206 1207 1208
	if (error)
		goto cleanup;
	if (is.s.not_found)
1209
		error = ext4_xattr_block_find(inode, &i, &bs);
1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225
	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)
1226
			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1227
		else if (!bs.s.not_found)
1228
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1229
	} else {
1230 1231 1232 1233 1234 1235 1236
		error = 0;
		/* Xattr value did not change? Save us some work and bail out */
		if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
			goto cleanup;
		if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
			goto cleanup;

1237
		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1238 1239
		if (!error && !bs.s.not_found) {
			i.value = NULL;
1240
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1241
		} else if (error == -ENOSPC) {
1242 1243 1244 1245 1246
			if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
				error = ext4_xattr_block_find(inode, &i, &bs);
				if (error)
					goto cleanup;
			}
1247
			error = ext4_xattr_block_set(handle, inode, &i, &bs);
1248 1249 1250 1251
			if (error)
				goto cleanup;
			if (!is.s.not_found) {
				i.value = NULL;
1252
				error = ext4_xattr_ibody_set(handle, inode, &i,
1253 1254 1255 1256 1257
							     &is);
			}
		}
	}
	if (!error) {
1258
		ext4_xattr_update_super_block(handle, inode->i_sb);
K
Kalpak Shah 已提交
1259
		inode->i_ctime = ext4_current_time(inode);
1260
		if (!value)
1261
			ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1262
		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1263
		/*
1264
		 * The bh is consumed by ext4_mark_iloc_dirty, even with
1265 1266 1267 1268
		 * error != 0.
		 */
		is.iloc.bh = NULL;
		if (IS_SYNC(inode))
1269
			ext4_handle_sync(handle);
1270 1271 1272 1273 1274
	}

cleanup:
	brelse(is.iloc.bh);
	brelse(bs.bh);
K
Kalpak Shah 已提交
1275
	if (no_expand == 0)
1276
		ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1277
	up_write(&EXT4_I(inode)->xattr_sem);
1278 1279 1280 1281
	return error;
}

/*
1282
 * ext4_xattr_set()
1283
 *
1284
 * Like ext4_xattr_set_handle, but start from an inode. This extended
1285 1286 1287 1288 1289
 * attribute modification is a filesystem transaction by itself.
 *
 * Returns 0, or a negative error number on failure.
 */
int
1290
ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1291 1292 1293 1294
	       const void *value, size_t value_len, int flags)
{
	handle_t *handle;
	int error, retries = 0;
1295
	int credits = ext4_jbd2_credits_xattr(inode);
1296 1297

retry:
1298
	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1299 1300 1301 1302 1303
	if (IS_ERR(handle)) {
		error = PTR_ERR(handle);
	} else {
		int error2;

1304
		error = ext4_xattr_set_handle(handle, inode, name_index, name,
1305
					      value, value_len, flags);
1306
		error2 = ext4_journal_stop(handle);
1307
		if (error == -ENOSPC &&
1308
		    ext4_should_retry_alloc(inode->i_sb, &retries))
1309 1310 1311 1312 1313 1314 1315 1316
			goto retry;
		if (error == 0)
			error = error2;
	}

	return error;
}

1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354
/*
 * 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;
1355 1356
	size_t min_offs;
	size_t ifree, bfree;
1357
	int total_ino;
1358
	void *base, *start, *end;
1359
	int error = 0, tried_min_extra_isize = 0;
A
Aneesh Kumar K.V 已提交
1360
	int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1361
	int isize_diff;	/* How much do we need to grow i_extra_isize */
1362 1363

	down_write(&EXT4_I(inode)->xattr_sem);
1364 1365 1366 1367
	/*
	 * Set EXT4_STATE_NO_EXPAND to avoid recursion when marking inode dirty
	 */
	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1368
retry:
1369
	isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
1370 1371
	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
		goto out;
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386

	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);

1387 1388 1389 1390
	error = xattr_check_inode(inode, header, end);
	if (error)
		goto cleanup;

1391 1392 1393
	ifree = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
	if (ifree >= isize_diff)
		goto shift;
1394 1395 1396 1397 1398 1399 1400 1401 1402 1403

	/*
	 * 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;
1404
		if (ext4_xattr_check_block(inode, bh)) {
1405 1406
			EXT4_ERROR_INODE(inode, "bad block %llu",
					 EXT4_I(inode)->i_file_acl);
1407
			error = -EFSCORRUPTED;
1408 1409 1410 1411 1412 1413
			goto cleanup;
		}
		base = BHDR(bh);
		first = BFIRST(bh);
		end = bh->b_data + bh->b_size;
		min_offs = end - base;
1414 1415
		bfree = ext4_xattr_free_space(first, &min_offs, base, NULL);
		if (bfree + ifree < isize_diff) {
1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
			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 {
1426
		bfree = inode->i_sb->s_blocksize;
1427 1428
	}

1429
	while (isize_diff > ifree) {
1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457
		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 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);
1458 1459 1460
			if (total_size <= bfree &&
			    total_size < min_total_size) {
				if (total_size + ifree < isize_diff) {
1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476
					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;
D
Dave Jones 已提交
1477 1478
					kfree(is); is = NULL;
					kfree(bs); bs = NULL;
1479
					brelse(bh);
1480 1481 1482 1483 1484 1485 1486 1487 1488
					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);
1489
		total_size = entry_size + EXT4_XATTR_SIZE(size);
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513
		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);
1514 1515
		if (error)
			goto cleanup;
1516
		total_ino -= entry_size;
1517 1518
		ifree += total_size;
		bfree -= total_size;
1519 1520 1521

		i.name = b_entry_name;
		i.value = buffer;
A
Aneesh Kumar K.V 已提交
1522
		i.value_len = size;
1523 1524 1525 1526 1527 1528 1529 1530 1531 1532
		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);
1533 1534
		b_entry_name = NULL;
		buffer = NULL;
1535 1536 1537 1538
		brelse(is->iloc.bh);
		kfree(is);
		kfree(bs);
	}
1539 1540 1541 1542 1543 1544 1545 1546 1547

shift:
	/* Adjust the offsets and shift the remaining entries ahead */
	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;
1548
	brelse(bh);
1549 1550
out:
	ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561
	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);
1562 1563 1564 1565
	/*
	 * We deliberately leave EXT4_STATE_NO_EXPAND set here since inode
	 * size expansion failed.
	 */
1566 1567 1568 1569 1570 1571
	up_write(&EXT4_I(inode)->xattr_sem);
	return error;
}



1572
/*
1573
 * ext4_xattr_delete_inode()
1574 1575 1576 1577 1578 1579
 *
 * 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
1580
ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1581 1582 1583
{
	struct buffer_head *bh = NULL;

1584
	if (!EXT4_I(inode)->i_file_acl)
1585
		goto cleanup;
1586
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1587
	if (!bh) {
1588 1589
		EXT4_ERROR_INODE(inode, "block %llu read error",
				 EXT4_I(inode)->i_file_acl);
1590 1591
		goto cleanup;
	}
1592
	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1593
	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1594 1595
		EXT4_ERROR_INODE(inode, "bad block %llu",
				 EXT4_I(inode)->i_file_acl);
1596 1597
		goto cleanup;
	}
1598 1599
	ext4_xattr_release_block(handle, inode, bh);
	EXT4_I(inode)->i_file_acl = 0;
1600 1601 1602 1603 1604 1605

cleanup:
	brelse(bh);
}

/*
1606
 * ext4_xattr_cache_insert()
1607 1608 1609 1610 1611 1612 1613
 *
 * 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
J
Jan Kara 已提交
1614
ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1615
{
1616 1617 1618 1619
	struct ext4_xattr_header *header = BHDR(bh);
	__u32 hash = le32_to_cpu(header->h_hash);
	int reusable = le32_to_cpu(header->h_refcount) <
		       EXT4_XATTR_REFCOUNT_MAX;
1620 1621
	int error;

J
Jan Kara 已提交
1622
	error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1623
				      bh->b_blocknr, reusable);
1624
	if (error) {
J
Jan Kara 已提交
1625
		if (error == -EBUSY)
1626
			ea_bdebug(bh, "already in cache");
J
Jan Kara 已提交
1627
	} else
1628 1629 1630 1631
		ea_bdebug(bh, "inserting [%x]", (int)hash);
}

/*
1632
 * ext4_xattr_cmp()
1633 1634 1635 1636 1637 1638 1639
 *
 * 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
1640 1641
ext4_xattr_cmp(struct ext4_xattr_header *header1,
	       struct ext4_xattr_header *header2)
1642
{
1643
	struct ext4_xattr_entry *entry1, *entry2;
1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656

	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)
1657
			return -EFSCORRUPTED;
1658 1659 1660 1661 1662
		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;

1663 1664
		entry1 = EXT4_XATTR_NEXT(entry1);
		entry2 = EXT4_XATTR_NEXT(entry2);
1665 1666 1667 1668 1669 1670 1671
	}
	if (!IS_LAST_ENTRY(entry2))
		return 1;
	return 0;
}

/*
1672
 * ext4_xattr_cache_find()
1673 1674 1675 1676 1677 1678 1679
 *
 * 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 *
1680
ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
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		      struct mb_cache_entry **pce)
1682 1683
{
	__u32 hash = le32_to_cpu(header->h_hash);
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1684 1685
	struct mb_cache_entry *ce;
	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1686 1687 1688 1689

	if (!header->h_hash)
		return NULL;  /* never share */
	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
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	ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1691 1692 1693 1694 1695
	while (ce) {
		struct buffer_head *bh;

		bh = sb_bread(inode->i_sb, ce->e_block);
		if (!bh) {
1696 1697
			EXT4_ERROR_INODE(inode, "block %lu read error",
					 (unsigned long) ce->e_block);
1698
		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1699 1700 1701 1702
			*pce = ce;
			return bh;
		}
		brelse(bh);
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		ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1704 1705 1706 1707 1708 1709 1710 1711
	}
	return NULL;
}

#define NAME_HASH_SHIFT 5
#define VALUE_HASH_SHIFT 16

/*
1712
 * ext4_xattr_hash_entry()
1713 1714 1715
 *
 * Compute the hash of an extended attribute.
 */
1716 1717
static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
					 struct ext4_xattr_entry *entry)
1718 1719 1720 1721 1722
{
	__u32 hash = 0;
	char *name = entry->e_name;
	int n;

1723
	for (n = 0; n < entry->e_name_len; n++) {
1724 1725 1726 1727 1728 1729 1730 1731 1732
		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) +
1733
		     EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747
			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

/*
1748
 * ext4_xattr_rehash()
1749 1750 1751
 *
 * Re-compute the extended attribute hash value after an entry has changed.
 */
1752 1753
static void ext4_xattr_rehash(struct ext4_xattr_header *header,
			      struct ext4_xattr_entry *entry)
1754
{
1755
	struct ext4_xattr_entry *here;
1756 1757
	__u32 hash = 0;

1758
	ext4_xattr_hash_entry(header, entry);
1759 1760 1761 1762 1763 1764 1765 1766 1767 1768
	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);
1769
		here = EXT4_XATTR_NEXT(here);
1770 1771 1772 1773 1774 1775
	}
	header->h_hash = cpu_to_le32(hash);
}

#undef BLOCK_HASH_SHIFT

1776 1777
#define	HASH_BUCKET_BITS	10

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struct mb_cache *
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1779
ext4_xattr_create_cache(void)
1780
{
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1781
	return mb_cache_create(HASH_BUCKET_BITS);
1782 1783
}

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void ext4_xattr_destroy_cache(struct mb_cache *cache)
1785
{
1786
	if (cache)
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		mb_cache_destroy(cache);
1788
}
1789