2 * linux/fs/ext4/xattr.c
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
28 * +------------------+
31 * | entry 2 | | growing downwards
36 * | value 3 | | growing upwards
38 * +------------------+
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
53 #include <linux/init.h>
55 #include <linux/slab.h>
56 #include <linux/mbcache.h>
57 #include <linux/quotaops.h>
58 #include <linux/rwsem.h>
59 #include "ext4_jbd2.h"
64 #ifdef EXT4_XATTR_DEBUG
65 # define ea_idebug(inode, f...) do { \
66 printk(KERN_DEBUG "inode %s:%lu: ", \
67 inode->i_sb->s_id, inode->i_ino); \
71 # define ea_bdebug(bh, f...) do { \
72 char b[BDEVNAME_SIZE]; \
73 printk(KERN_DEBUG "block %s:%lu: ", \
74 bdevname(bh->b_bdev, b), \
75 (unsigned long) bh->b_blocknr); \
80 # define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
81 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
84 static void ext4_xattr_cache_insert(struct mb_cache
*, struct buffer_head
*);
85 static struct buffer_head
*ext4_xattr_cache_find(struct inode
*,
86 struct ext4_xattr_header
*,
87 struct mb_cache_entry
**);
88 static void ext4_xattr_rehash(struct ext4_xattr_header
*,
89 struct ext4_xattr_entry
*);
90 static int ext4_xattr_list(struct dentry
*dentry
, char *buffer
,
93 static const struct xattr_handler
*ext4_xattr_handler_map
[] = {
94 [EXT4_XATTR_INDEX_USER
] = &ext4_xattr_user_handler
,
95 #ifdef CONFIG_EXT4_FS_POSIX_ACL
96 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS
] = &posix_acl_access_xattr_handler
,
97 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT
] = &posix_acl_default_xattr_handler
,
99 [EXT4_XATTR_INDEX_TRUSTED
] = &ext4_xattr_trusted_handler
,
100 #ifdef CONFIG_EXT4_FS_SECURITY
101 [EXT4_XATTR_INDEX_SECURITY
] = &ext4_xattr_security_handler
,
105 const struct xattr_handler
*ext4_xattr_handlers
[] = {
106 &ext4_xattr_user_handler
,
107 &ext4_xattr_trusted_handler
,
108 #ifdef CONFIG_EXT4_FS_POSIX_ACL
109 &posix_acl_access_xattr_handler
,
110 &posix_acl_default_xattr_handler
,
112 #ifdef CONFIG_EXT4_FS_SECURITY
113 &ext4_xattr_security_handler
,
118 #define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \
119 inode->i_sb->s_fs_info)->s_mb_cache)
121 static __le32
ext4_xattr_block_csum(struct inode
*inode
,
123 struct ext4_xattr_header
*hdr
)
125 struct ext4_sb_info
*sbi
= EXT4_SB(inode
->i_sb
);
128 __le64 dsk_block_nr
= cpu_to_le64(block_nr
);
130 save_csum
= hdr
->h_checksum
;
132 csum
= ext4_chksum(sbi
, sbi
->s_csum_seed
, (__u8
*)&dsk_block_nr
,
133 sizeof(dsk_block_nr
));
134 csum
= ext4_chksum(sbi
, csum
, (__u8
*)hdr
,
135 EXT4_BLOCK_SIZE(inode
->i_sb
));
137 hdr
->h_checksum
= save_csum
;
138 return cpu_to_le32(csum
);
141 static int ext4_xattr_block_csum_verify(struct inode
*inode
,
143 struct ext4_xattr_header
*hdr
)
145 if (EXT4_HAS_RO_COMPAT_FEATURE(inode
->i_sb
,
146 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM
) &&
147 (hdr
->h_checksum
!= ext4_xattr_block_csum(inode
, block_nr
, hdr
)))
152 static void ext4_xattr_block_csum_set(struct inode
*inode
,
154 struct ext4_xattr_header
*hdr
)
156 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode
->i_sb
,
157 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM
))
160 hdr
->h_checksum
= ext4_xattr_block_csum(inode
, block_nr
, hdr
);
163 static inline int ext4_handle_dirty_xattr_block(handle_t
*handle
,
165 struct buffer_head
*bh
)
167 ext4_xattr_block_csum_set(inode
, bh
->b_blocknr
, BHDR(bh
));
168 return ext4_handle_dirty_metadata(handle
, inode
, bh
);
171 static inline const struct xattr_handler
*
172 ext4_xattr_handler(int name_index
)
174 const struct xattr_handler
*handler
= NULL
;
176 if (name_index
> 0 && name_index
< ARRAY_SIZE(ext4_xattr_handler_map
))
177 handler
= ext4_xattr_handler_map
[name_index
];
182 * Inode operation listxattr()
184 * dentry->d_inode->i_mutex: don't care
187 ext4_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
189 return ext4_xattr_list(dentry
, buffer
, size
);
193 ext4_xattr_check_names(struct ext4_xattr_entry
*entry
, void *end
)
195 while (!IS_LAST_ENTRY(entry
)) {
196 struct ext4_xattr_entry
*next
= EXT4_XATTR_NEXT(entry
);
197 if ((void *)next
>= end
)
205 ext4_xattr_check_block(struct inode
*inode
, struct buffer_head
*bh
)
209 if (buffer_verified(bh
))
212 if (BHDR(bh
)->h_magic
!= cpu_to_le32(EXT4_XATTR_MAGIC
) ||
213 BHDR(bh
)->h_blocks
!= cpu_to_le32(1))
215 if (!ext4_xattr_block_csum_verify(inode
, bh
->b_blocknr
, BHDR(bh
)))
217 error
= ext4_xattr_check_names(BFIRST(bh
), bh
->b_data
+ bh
->b_size
);
219 set_buffer_verified(bh
);
224 ext4_xattr_check_entry(struct ext4_xattr_entry
*entry
, size_t size
)
226 size_t value_size
= le32_to_cpu(entry
->e_value_size
);
228 if (entry
->e_value_block
!= 0 || value_size
> size
||
229 le16_to_cpu(entry
->e_value_offs
) + value_size
> size
)
235 ext4_xattr_find_entry(struct ext4_xattr_entry
**pentry
, int name_index
,
236 const char *name
, size_t size
, int sorted
)
238 struct ext4_xattr_entry
*entry
;
244 name_len
= strlen(name
);
246 for (; !IS_LAST_ENTRY(entry
); entry
= EXT4_XATTR_NEXT(entry
)) {
247 cmp
= name_index
- entry
->e_name_index
;
249 cmp
= name_len
- entry
->e_name_len
;
251 cmp
= memcmp(name
, entry
->e_name
, name_len
);
252 if (cmp
<= 0 && (sorted
|| cmp
== 0))
256 if (!cmp
&& ext4_xattr_check_entry(entry
, size
))
258 return cmp
? -ENODATA
: 0;
262 ext4_xattr_block_get(struct inode
*inode
, int name_index
, const char *name
,
263 void *buffer
, size_t buffer_size
)
265 struct buffer_head
*bh
= NULL
;
266 struct ext4_xattr_entry
*entry
;
269 struct mb_cache
*ext4_mb_cache
= EXT4_GET_MB_CACHE(inode
);
271 ea_idebug(inode
, "name=%d.%s, buffer=%p, buffer_size=%ld",
272 name_index
, name
, buffer
, (long)buffer_size
);
275 if (!EXT4_I(inode
)->i_file_acl
)
277 ea_idebug(inode
, "reading block %llu",
278 (unsigned long long)EXT4_I(inode
)->i_file_acl
);
279 bh
= sb_bread(inode
->i_sb
, EXT4_I(inode
)->i_file_acl
);
282 ea_bdebug(bh
, "b_count=%d, refcount=%d",
283 atomic_read(&(bh
->b_count
)), le32_to_cpu(BHDR(bh
)->h_refcount
));
284 if (ext4_xattr_check_block(inode
, bh
)) {
286 EXT4_ERROR_INODE(inode
, "bad block %llu",
287 EXT4_I(inode
)->i_file_acl
);
291 ext4_xattr_cache_insert(ext4_mb_cache
, bh
);
293 error
= ext4_xattr_find_entry(&entry
, name_index
, name
, bh
->b_size
, 1);
298 size
= le32_to_cpu(entry
->e_value_size
);
301 if (size
> buffer_size
)
303 memcpy(buffer
, bh
->b_data
+ le16_to_cpu(entry
->e_value_offs
),
314 ext4_xattr_ibody_get(struct inode
*inode
, int name_index
, const char *name
,
315 void *buffer
, size_t buffer_size
)
317 struct ext4_xattr_ibody_header
*header
;
318 struct ext4_xattr_entry
*entry
;
319 struct ext4_inode
*raw_inode
;
320 struct ext4_iloc iloc
;
325 if (!ext4_test_inode_state(inode
, EXT4_STATE_XATTR
))
327 error
= ext4_get_inode_loc(inode
, &iloc
);
330 raw_inode
= ext4_raw_inode(&iloc
);
331 header
= IHDR(inode
, raw_inode
);
332 entry
= IFIRST(header
);
333 end
= (void *)raw_inode
+ EXT4_SB(inode
->i_sb
)->s_inode_size
;
334 error
= ext4_xattr_check_names(entry
, end
);
337 error
= ext4_xattr_find_entry(&entry
, name_index
, name
,
338 end
- (void *)entry
, 0);
341 size
= le32_to_cpu(entry
->e_value_size
);
344 if (size
> buffer_size
)
346 memcpy(buffer
, (void *)IFIRST(header
) +
347 le16_to_cpu(entry
->e_value_offs
), size
);
359 * Copy an extended attribute into the buffer
360 * provided, or compute the buffer size required.
361 * Buffer is NULL to compute the size of the buffer required.
363 * Returns a negative error number on failure, or the number of bytes
364 * used / required on success.
367 ext4_xattr_get(struct inode
*inode
, int name_index
, const char *name
,
368 void *buffer
, size_t buffer_size
)
372 if (strlen(name
) > 255)
375 down_read(&EXT4_I(inode
)->xattr_sem
);
376 error
= ext4_xattr_ibody_get(inode
, name_index
, name
, buffer
,
378 if (error
== -ENODATA
)
379 error
= ext4_xattr_block_get(inode
, name_index
, name
, buffer
,
381 up_read(&EXT4_I(inode
)->xattr_sem
);
386 ext4_xattr_list_entries(struct dentry
*dentry
, struct ext4_xattr_entry
*entry
,
387 char *buffer
, size_t buffer_size
)
389 size_t rest
= buffer_size
;
391 for (; !IS_LAST_ENTRY(entry
); entry
= EXT4_XATTR_NEXT(entry
)) {
392 const struct xattr_handler
*handler
=
393 ext4_xattr_handler(entry
->e_name_index
);
396 size_t size
= handler
->list(dentry
, buffer
, rest
,
408 return buffer_size
- rest
;
412 ext4_xattr_block_list(struct dentry
*dentry
, char *buffer
, size_t buffer_size
)
414 struct inode
*inode
= dentry
->d_inode
;
415 struct buffer_head
*bh
= NULL
;
417 struct mb_cache
*ext4_mb_cache
= EXT4_GET_MB_CACHE(inode
);
419 ea_idebug(inode
, "buffer=%p, buffer_size=%ld",
420 buffer
, (long)buffer_size
);
423 if (!EXT4_I(inode
)->i_file_acl
)
425 ea_idebug(inode
, "reading block %llu",
426 (unsigned long long)EXT4_I(inode
)->i_file_acl
);
427 bh
= sb_bread(inode
->i_sb
, EXT4_I(inode
)->i_file_acl
);
431 ea_bdebug(bh
, "b_count=%d, refcount=%d",
432 atomic_read(&(bh
->b_count
)), le32_to_cpu(BHDR(bh
)->h_refcount
));
433 if (ext4_xattr_check_block(inode
, bh
)) {
434 EXT4_ERROR_INODE(inode
, "bad block %llu",
435 EXT4_I(inode
)->i_file_acl
);
439 ext4_xattr_cache_insert(ext4_mb_cache
, bh
);
440 error
= ext4_xattr_list_entries(dentry
, BFIRST(bh
), buffer
, buffer_size
);
449 ext4_xattr_ibody_list(struct dentry
*dentry
, char *buffer
, size_t buffer_size
)
451 struct inode
*inode
= dentry
->d_inode
;
452 struct ext4_xattr_ibody_header
*header
;
453 struct ext4_inode
*raw_inode
;
454 struct ext4_iloc iloc
;
458 if (!ext4_test_inode_state(inode
, EXT4_STATE_XATTR
))
460 error
= ext4_get_inode_loc(inode
, &iloc
);
463 raw_inode
= ext4_raw_inode(&iloc
);
464 header
= IHDR(inode
, raw_inode
);
465 end
= (void *)raw_inode
+ EXT4_SB(inode
->i_sb
)->s_inode_size
;
466 error
= ext4_xattr_check_names(IFIRST(header
), end
);
469 error
= ext4_xattr_list_entries(dentry
, IFIRST(header
),
470 buffer
, buffer_size
);
480 * Copy a list of attribute names into the buffer
481 * provided, or compute the buffer size required.
482 * Buffer is NULL to compute the size of the buffer required.
484 * Returns a negative error number on failure, or the number of bytes
485 * used / required on success.
488 ext4_xattr_list(struct dentry
*dentry
, char *buffer
, size_t buffer_size
)
492 down_read(&EXT4_I(dentry
->d_inode
)->xattr_sem
);
493 ret
= ret2
= ext4_xattr_ibody_list(dentry
, buffer
, buffer_size
);
500 ret
= ext4_xattr_block_list(dentry
, buffer
, buffer_size
);
505 up_read(&EXT4_I(dentry
->d_inode
)->xattr_sem
);
510 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
513 static void ext4_xattr_update_super_block(handle_t
*handle
,
514 struct super_block
*sb
)
516 if (EXT4_HAS_COMPAT_FEATURE(sb
, EXT4_FEATURE_COMPAT_EXT_ATTR
))
519 BUFFER_TRACE(EXT4_SB(sb
)->s_sbh
, "get_write_access");
520 if (ext4_journal_get_write_access(handle
, EXT4_SB(sb
)->s_sbh
) == 0) {
521 EXT4_SET_COMPAT_FEATURE(sb
, EXT4_FEATURE_COMPAT_EXT_ATTR
);
522 ext4_handle_dirty_super(handle
, sb
);
527 * Release the xattr block BH: If the reference count is > 1, decrement it;
528 * otherwise free the block.
531 ext4_xattr_release_block(handle_t
*handle
, struct inode
*inode
,
532 struct buffer_head
*bh
)
534 struct mb_cache_entry
*ce
= NULL
;
536 struct mb_cache
*ext4_mb_cache
= EXT4_GET_MB_CACHE(inode
);
538 ce
= mb_cache_entry_get(ext4_mb_cache
, bh
->b_bdev
, bh
->b_blocknr
);
539 BUFFER_TRACE(bh
, "get_write_access");
540 error
= ext4_journal_get_write_access(handle
, bh
);
545 if (BHDR(bh
)->h_refcount
== cpu_to_le32(1)) {
546 ea_bdebug(bh
, "refcount now=0; freeing");
548 mb_cache_entry_free(ce
);
551 ext4_free_blocks(handle
, inode
, bh
, 0, 1,
552 EXT4_FREE_BLOCKS_METADATA
|
553 EXT4_FREE_BLOCKS_FORGET
);
555 le32_add_cpu(&BHDR(bh
)->h_refcount
, -1);
557 mb_cache_entry_release(ce
);
559 * Beware of this ugliness: Releasing of xattr block references
560 * from different inodes can race and so we have to protect
561 * from a race where someone else frees the block (and releases
562 * its journal_head) before we are done dirtying the buffer. In
563 * nojournal mode this race is harmless and we actually cannot
564 * call ext4_handle_dirty_xattr_block() with locked buffer as
565 * that function can call sync_dirty_buffer() so for that case
566 * we handle the dirtying after unlocking the buffer.
568 if (ext4_handle_valid(handle
))
569 error
= ext4_handle_dirty_xattr_block(handle
, inode
,
572 if (!ext4_handle_valid(handle
))
573 error
= ext4_handle_dirty_xattr_block(handle
, inode
,
576 ext4_handle_sync(handle
);
577 dquot_free_block(inode
, EXT4_C2B(EXT4_SB(inode
->i_sb
), 1));
578 ea_bdebug(bh
, "refcount now=%d; releasing",
579 le32_to_cpu(BHDR(bh
)->h_refcount
));
582 ext4_std_error(inode
->i_sb
, error
);
587 * Find the available free space for EAs. This also returns the total number of
588 * bytes used by EA entries.
590 static size_t ext4_xattr_free_space(struct ext4_xattr_entry
*last
,
591 size_t *min_offs
, void *base
, int *total
)
593 for (; !IS_LAST_ENTRY(last
); last
= EXT4_XATTR_NEXT(last
)) {
594 if (!last
->e_value_block
&& last
->e_value_size
) {
595 size_t offs
= le16_to_cpu(last
->e_value_offs
);
596 if (offs
< *min_offs
)
600 *total
+= EXT4_XATTR_LEN(last
->e_name_len
);
602 return (*min_offs
- ((void *)last
- base
) - sizeof(__u32
));
606 ext4_xattr_set_entry(struct ext4_xattr_info
*i
, struct ext4_xattr_search
*s
)
608 struct ext4_xattr_entry
*last
;
609 size_t free
, min_offs
= s
->end
- s
->base
, name_len
= strlen(i
->name
);
611 /* Compute min_offs and last. */
613 for (; !IS_LAST_ENTRY(last
); last
= EXT4_XATTR_NEXT(last
)) {
614 if (!last
->e_value_block
&& last
->e_value_size
) {
615 size_t offs
= le16_to_cpu(last
->e_value_offs
);
620 free
= min_offs
- ((void *)last
- s
->base
) - sizeof(__u32
);
622 if (!s
->here
->e_value_block
&& s
->here
->e_value_size
) {
623 size_t size
= le32_to_cpu(s
->here
->e_value_size
);
624 free
+= EXT4_XATTR_SIZE(size
);
626 free
+= EXT4_XATTR_LEN(name_len
);
629 if (free
< EXT4_XATTR_SIZE(i
->value_len
) ||
630 free
< EXT4_XATTR_LEN(name_len
) +
631 EXT4_XATTR_SIZE(i
->value_len
))
635 if (i
->value
&& s
->not_found
) {
636 /* Insert the new name. */
637 size_t size
= EXT4_XATTR_LEN(name_len
);
638 size_t rest
= (void *)last
- (void *)s
->here
+ sizeof(__u32
);
639 memmove((void *)s
->here
+ size
, s
->here
, rest
);
640 memset(s
->here
, 0, size
);
641 s
->here
->e_name_index
= i
->name_index
;
642 s
->here
->e_name_len
= name_len
;
643 memcpy(s
->here
->e_name
, i
->name
, name_len
);
645 if (!s
->here
->e_value_block
&& s
->here
->e_value_size
) {
646 void *first_val
= s
->base
+ min_offs
;
647 size_t offs
= le16_to_cpu(s
->here
->e_value_offs
);
648 void *val
= s
->base
+ offs
;
649 size_t size
= EXT4_XATTR_SIZE(
650 le32_to_cpu(s
->here
->e_value_size
));
652 if (i
->value
&& size
== EXT4_XATTR_SIZE(i
->value_len
)) {
653 /* The old and the new value have the same
654 size. Just replace. */
655 s
->here
->e_value_size
=
656 cpu_to_le32(i
->value_len
);
657 if (i
->value
== EXT4_ZERO_XATTR_VALUE
) {
658 memset(val
, 0, size
);
660 /* Clear pad bytes first. */
661 memset(val
+ size
- EXT4_XATTR_PAD
, 0,
663 memcpy(val
, i
->value
, i
->value_len
);
668 /* Remove the old value. */
669 memmove(first_val
+ size
, first_val
, val
- first_val
);
670 memset(first_val
, 0, size
);
671 s
->here
->e_value_size
= 0;
672 s
->here
->e_value_offs
= 0;
675 /* Adjust all value offsets. */
677 while (!IS_LAST_ENTRY(last
)) {
678 size_t o
= le16_to_cpu(last
->e_value_offs
);
679 if (!last
->e_value_block
&&
680 last
->e_value_size
&& o
< offs
)
682 cpu_to_le16(o
+ size
);
683 last
= EXT4_XATTR_NEXT(last
);
687 /* Remove the old name. */
688 size_t size
= EXT4_XATTR_LEN(name_len
);
689 last
= ENTRY((void *)last
- size
);
690 memmove(s
->here
, (void *)s
->here
+ size
,
691 (void *)last
- (void *)s
->here
+ sizeof(__u32
));
692 memset(last
, 0, size
);
697 /* Insert the new value. */
698 s
->here
->e_value_size
= cpu_to_le32(i
->value_len
);
700 size_t size
= EXT4_XATTR_SIZE(i
->value_len
);
701 void *val
= s
->base
+ min_offs
- size
;
702 s
->here
->e_value_offs
= cpu_to_le16(min_offs
- size
);
703 if (i
->value
== EXT4_ZERO_XATTR_VALUE
) {
704 memset(val
, 0, size
);
706 /* Clear the pad bytes first. */
707 memset(val
+ size
- EXT4_XATTR_PAD
, 0,
709 memcpy(val
, i
->value
, i
->value_len
);
716 struct ext4_xattr_block_find
{
717 struct ext4_xattr_search s
;
718 struct buffer_head
*bh
;
722 ext4_xattr_block_find(struct inode
*inode
, struct ext4_xattr_info
*i
,
723 struct ext4_xattr_block_find
*bs
)
725 struct super_block
*sb
= inode
->i_sb
;
728 ea_idebug(inode
, "name=%d.%s, value=%p, value_len=%ld",
729 i
->name_index
, i
->name
, i
->value
, (long)i
->value_len
);
731 if (EXT4_I(inode
)->i_file_acl
) {
732 /* The inode already has an extended attribute block. */
733 bs
->bh
= sb_bread(sb
, EXT4_I(inode
)->i_file_acl
);
737 ea_bdebug(bs
->bh
, "b_count=%d, refcount=%d",
738 atomic_read(&(bs
->bh
->b_count
)),
739 le32_to_cpu(BHDR(bs
->bh
)->h_refcount
));
740 if (ext4_xattr_check_block(inode
, bs
->bh
)) {
741 EXT4_ERROR_INODE(inode
, "bad block %llu",
742 EXT4_I(inode
)->i_file_acl
);
746 /* Find the named attribute. */
747 bs
->s
.base
= BHDR(bs
->bh
);
748 bs
->s
.first
= BFIRST(bs
->bh
);
749 bs
->s
.end
= bs
->bh
->b_data
+ bs
->bh
->b_size
;
750 bs
->s
.here
= bs
->s
.first
;
751 error
= ext4_xattr_find_entry(&bs
->s
.here
, i
->name_index
,
752 i
->name
, bs
->bh
->b_size
, 1);
753 if (error
&& error
!= -ENODATA
)
755 bs
->s
.not_found
= error
;
764 ext4_xattr_block_set(handle_t
*handle
, struct inode
*inode
,
765 struct ext4_xattr_info
*i
,
766 struct ext4_xattr_block_find
*bs
)
768 struct super_block
*sb
= inode
->i_sb
;
769 struct buffer_head
*new_bh
= NULL
;
770 struct ext4_xattr_search
*s
= &bs
->s
;
771 struct mb_cache_entry
*ce
= NULL
;
773 struct mb_cache
*ext4_mb_cache
= EXT4_GET_MB_CACHE(inode
);
775 #define header(x) ((struct ext4_xattr_header *)(x))
777 if (i
->value
&& i
->value_len
> sb
->s_blocksize
)
780 ce
= mb_cache_entry_get(ext4_mb_cache
, bs
->bh
->b_bdev
,
782 BUFFER_TRACE(bs
->bh
, "get_write_access");
783 error
= ext4_journal_get_write_access(handle
, bs
->bh
);
788 if (header(s
->base
)->h_refcount
== cpu_to_le32(1)) {
790 mb_cache_entry_free(ce
);
793 ea_bdebug(bs
->bh
, "modifying in-place");
794 error
= ext4_xattr_set_entry(i
, s
);
796 if (!IS_LAST_ENTRY(s
->first
))
797 ext4_xattr_rehash(header(s
->base
),
799 ext4_xattr_cache_insert(ext4_mb_cache
,
802 unlock_buffer(bs
->bh
);
806 error
= ext4_handle_dirty_xattr_block(handle
,
813 int offset
= (char *)s
->here
- bs
->bh
->b_data
;
815 unlock_buffer(bs
->bh
);
817 mb_cache_entry_release(ce
);
820 ea_bdebug(bs
->bh
, "cloning");
821 s
->base
= kmalloc(bs
->bh
->b_size
, GFP_NOFS
);
825 memcpy(s
->base
, BHDR(bs
->bh
), bs
->bh
->b_size
);
826 s
->first
= ENTRY(header(s
->base
)+1);
827 header(s
->base
)->h_refcount
= cpu_to_le32(1);
828 s
->here
= ENTRY(s
->base
+ offset
);
829 s
->end
= s
->base
+ bs
->bh
->b_size
;
832 /* Allocate a buffer where we construct the new block. */
833 s
->base
= kzalloc(sb
->s_blocksize
, GFP_NOFS
);
834 /* assert(header == s->base) */
838 header(s
->base
)->h_magic
= cpu_to_le32(EXT4_XATTR_MAGIC
);
839 header(s
->base
)->h_blocks
= cpu_to_le32(1);
840 header(s
->base
)->h_refcount
= cpu_to_le32(1);
841 s
->first
= ENTRY(header(s
->base
)+1);
842 s
->here
= ENTRY(header(s
->base
)+1);
843 s
->end
= s
->base
+ sb
->s_blocksize
;
846 error
= ext4_xattr_set_entry(i
, s
);
851 if (!IS_LAST_ENTRY(s
->first
))
852 ext4_xattr_rehash(header(s
->base
), s
->here
);
855 if (!IS_LAST_ENTRY(s
->first
)) {
856 new_bh
= ext4_xattr_cache_find(inode
, header(s
->base
), &ce
);
858 /* We found an identical block in the cache. */
859 if (new_bh
== bs
->bh
)
860 ea_bdebug(new_bh
, "keeping");
862 /* The old block is released after updating
864 error
= dquot_alloc_block(inode
,
865 EXT4_C2B(EXT4_SB(sb
), 1));
868 BUFFER_TRACE(new_bh
, "get_write_access");
869 error
= ext4_journal_get_write_access(handle
,
874 le32_add_cpu(&BHDR(new_bh
)->h_refcount
, 1);
875 ea_bdebug(new_bh
, "reusing; refcount now=%d",
876 le32_to_cpu(BHDR(new_bh
)->h_refcount
));
877 unlock_buffer(new_bh
);
878 error
= ext4_handle_dirty_xattr_block(handle
,
884 mb_cache_entry_release(ce
);
886 } else if (bs
->bh
&& s
->base
== bs
->bh
->b_data
) {
887 /* We were modifying this block in-place. */
888 ea_bdebug(bs
->bh
, "keeping this block");
892 /* We need to allocate a new block */
893 ext4_fsblk_t goal
, block
;
895 goal
= ext4_group_first_block_no(sb
,
896 EXT4_I(inode
)->i_block_group
);
898 /* non-extent files can't have physical blocks past 2^32 */
899 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)))
900 goal
= goal
& EXT4_MAX_BLOCK_FILE_PHYS
;
903 * take i_data_sem because we will test
904 * i_delalloc_reserved_flag in ext4_mb_new_blocks
906 down_read(&EXT4_I(inode
)->i_data_sem
);
907 block
= ext4_new_meta_blocks(handle
, inode
, goal
, 0,
909 up_read((&EXT4_I(inode
)->i_data_sem
));
913 if (!(ext4_test_inode_flag(inode
, EXT4_INODE_EXTENTS
)))
914 BUG_ON(block
> EXT4_MAX_BLOCK_FILE_PHYS
);
916 ea_idebug(inode
, "creating block %llu",
917 (unsigned long long)block
);
919 new_bh
= sb_getblk(sb
, block
);
920 if (unlikely(!new_bh
)) {
923 ext4_free_blocks(handle
, inode
, NULL
, block
, 1,
924 EXT4_FREE_BLOCKS_METADATA
);
928 error
= ext4_journal_get_create_access(handle
, new_bh
);
930 unlock_buffer(new_bh
);
934 memcpy(new_bh
->b_data
, s
->base
, new_bh
->b_size
);
935 set_buffer_uptodate(new_bh
);
936 unlock_buffer(new_bh
);
937 ext4_xattr_cache_insert(ext4_mb_cache
, new_bh
);
938 error
= ext4_handle_dirty_xattr_block(handle
,
945 /* Update the inode. */
946 EXT4_I(inode
)->i_file_acl
= new_bh
? new_bh
->b_blocknr
: 0;
948 /* Drop the previous xattr block. */
949 if (bs
->bh
&& bs
->bh
!= new_bh
)
950 ext4_xattr_release_block(handle
, inode
, bs
->bh
);
955 mb_cache_entry_release(ce
);
957 if (!(bs
->bh
&& s
->base
== bs
->bh
->b_data
))
963 dquot_free_block(inode
, EXT4_C2B(EXT4_SB(sb
), 1));
967 EXT4_ERROR_INODE(inode
, "bad block %llu",
968 EXT4_I(inode
)->i_file_acl
);
974 int ext4_xattr_ibody_find(struct inode
*inode
, struct ext4_xattr_info
*i
,
975 struct ext4_xattr_ibody_find
*is
)
977 struct ext4_xattr_ibody_header
*header
;
978 struct ext4_inode
*raw_inode
;
981 if (EXT4_I(inode
)->i_extra_isize
== 0)
983 raw_inode
= ext4_raw_inode(&is
->iloc
);
984 header
= IHDR(inode
, raw_inode
);
985 is
->s
.base
= is
->s
.first
= IFIRST(header
);
986 is
->s
.here
= is
->s
.first
;
987 is
->s
.end
= (void *)raw_inode
+ EXT4_SB(inode
->i_sb
)->s_inode_size
;
988 if (ext4_test_inode_state(inode
, EXT4_STATE_XATTR
)) {
989 error
= ext4_xattr_check_names(IFIRST(header
), is
->s
.end
);
992 /* Find the named attribute. */
993 error
= ext4_xattr_find_entry(&is
->s
.here
, i
->name_index
,
995 (void *)is
->s
.base
, 0);
996 if (error
&& error
!= -ENODATA
)
998 is
->s
.not_found
= error
;
1003 int ext4_xattr_ibody_inline_set(handle_t
*handle
, struct inode
*inode
,
1004 struct ext4_xattr_info
*i
,
1005 struct ext4_xattr_ibody_find
*is
)
1007 struct ext4_xattr_ibody_header
*header
;
1008 struct ext4_xattr_search
*s
= &is
->s
;
1011 if (EXT4_I(inode
)->i_extra_isize
== 0)
1013 error
= ext4_xattr_set_entry(i
, s
);
1015 if (error
== -ENOSPC
&&
1016 ext4_has_inline_data(inode
)) {
1017 error
= ext4_try_to_evict_inline_data(handle
, inode
,
1018 EXT4_XATTR_LEN(strlen(i
->name
) +
1019 EXT4_XATTR_SIZE(i
->value_len
)));
1022 error
= ext4_xattr_ibody_find(inode
, i
, is
);
1025 error
= ext4_xattr_set_entry(i
, s
);
1030 header
= IHDR(inode
, ext4_raw_inode(&is
->iloc
));
1031 if (!IS_LAST_ENTRY(s
->first
)) {
1032 header
->h_magic
= cpu_to_le32(EXT4_XATTR_MAGIC
);
1033 ext4_set_inode_state(inode
, EXT4_STATE_XATTR
);
1035 header
->h_magic
= cpu_to_le32(0);
1036 ext4_clear_inode_state(inode
, EXT4_STATE_XATTR
);
1041 static int ext4_xattr_ibody_set(handle_t
*handle
, struct inode
*inode
,
1042 struct ext4_xattr_info
*i
,
1043 struct ext4_xattr_ibody_find
*is
)
1045 struct ext4_xattr_ibody_header
*header
;
1046 struct ext4_xattr_search
*s
= &is
->s
;
1049 if (EXT4_I(inode
)->i_extra_isize
== 0)
1051 error
= ext4_xattr_set_entry(i
, s
);
1054 header
= IHDR(inode
, ext4_raw_inode(&is
->iloc
));
1055 if (!IS_LAST_ENTRY(s
->first
)) {
1056 header
->h_magic
= cpu_to_le32(EXT4_XATTR_MAGIC
);
1057 ext4_set_inode_state(inode
, EXT4_STATE_XATTR
);
1059 header
->h_magic
= cpu_to_le32(0);
1060 ext4_clear_inode_state(inode
, EXT4_STATE_XATTR
);
1066 * ext4_xattr_set_handle()
1068 * Create, replace or remove an extended attribute for this inode. Value
1069 * is NULL to remove an existing extended attribute, and non-NULL to
1070 * either replace an existing extended attribute, or create a new extended
1071 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1072 * specify that an extended attribute must exist and must not exist
1073 * previous to the call, respectively.
1075 * Returns 0, or a negative error number on failure.
1078 ext4_xattr_set_handle(handle_t
*handle
, struct inode
*inode
, int name_index
,
1079 const char *name
, const void *value
, size_t value_len
,
1082 struct ext4_xattr_info i
= {
1083 .name_index
= name_index
,
1086 .value_len
= value_len
,
1089 struct ext4_xattr_ibody_find is
= {
1090 .s
= { .not_found
= -ENODATA
, },
1092 struct ext4_xattr_block_find bs
= {
1093 .s
= { .not_found
= -ENODATA
, },
1095 unsigned long no_expand
;
1100 if (strlen(name
) > 255)
1102 down_write(&EXT4_I(inode
)->xattr_sem
);
1103 no_expand
= ext4_test_inode_state(inode
, EXT4_STATE_NO_EXPAND
);
1104 ext4_set_inode_state(inode
, EXT4_STATE_NO_EXPAND
);
1106 error
= ext4_reserve_inode_write(handle
, inode
, &is
.iloc
);
1110 if (ext4_test_inode_state(inode
, EXT4_STATE_NEW
)) {
1111 struct ext4_inode
*raw_inode
= ext4_raw_inode(&is
.iloc
);
1112 memset(raw_inode
, 0, EXT4_SB(inode
->i_sb
)->s_inode_size
);
1113 ext4_clear_inode_state(inode
, EXT4_STATE_NEW
);
1116 error
= ext4_xattr_ibody_find(inode
, &i
, &is
);
1120 error
= ext4_xattr_block_find(inode
, &i
, &bs
);
1123 if (is
.s
.not_found
&& bs
.s
.not_found
) {
1125 if (flags
& XATTR_REPLACE
)
1132 if (flags
& XATTR_CREATE
)
1136 if (!is
.s
.not_found
)
1137 error
= ext4_xattr_ibody_set(handle
, inode
, &i
, &is
);
1138 else if (!bs
.s
.not_found
)
1139 error
= ext4_xattr_block_set(handle
, inode
, &i
, &bs
);
1141 error
= ext4_xattr_ibody_set(handle
, inode
, &i
, &is
);
1142 if (!error
&& !bs
.s
.not_found
) {
1144 error
= ext4_xattr_block_set(handle
, inode
, &i
, &bs
);
1145 } else if (error
== -ENOSPC
) {
1146 if (EXT4_I(inode
)->i_file_acl
&& !bs
.s
.base
) {
1147 error
= ext4_xattr_block_find(inode
, &i
, &bs
);
1151 error
= ext4_xattr_block_set(handle
, inode
, &i
, &bs
);
1154 if (!is
.s
.not_found
) {
1156 error
= ext4_xattr_ibody_set(handle
, inode
, &i
,
1162 ext4_xattr_update_super_block(handle
, inode
->i_sb
);
1163 inode
->i_ctime
= ext4_current_time(inode
);
1165 ext4_clear_inode_state(inode
, EXT4_STATE_NO_EXPAND
);
1166 error
= ext4_mark_iloc_dirty(handle
, inode
, &is
.iloc
);
1168 * The bh is consumed by ext4_mark_iloc_dirty, even with
1173 ext4_handle_sync(handle
);
1180 ext4_clear_inode_state(inode
, EXT4_STATE_NO_EXPAND
);
1181 up_write(&EXT4_I(inode
)->xattr_sem
);
1188 * Like ext4_xattr_set_handle, but start from an inode. This extended
1189 * attribute modification is a filesystem transaction by itself.
1191 * Returns 0, or a negative error number on failure.
1194 ext4_xattr_set(struct inode
*inode
, int name_index
, const char *name
,
1195 const void *value
, size_t value_len
, int flags
)
1198 int error
, retries
= 0;
1199 int credits
= ext4_jbd2_credits_xattr(inode
);
1202 handle
= ext4_journal_start(inode
, EXT4_HT_XATTR
, credits
);
1203 if (IS_ERR(handle
)) {
1204 error
= PTR_ERR(handle
);
1208 error
= ext4_xattr_set_handle(handle
, inode
, name_index
, name
,
1209 value
, value_len
, flags
);
1210 error2
= ext4_journal_stop(handle
);
1211 if (error
== -ENOSPC
&&
1212 ext4_should_retry_alloc(inode
->i_sb
, &retries
))
1222 * Shift the EA entries in the inode to create space for the increased
1225 static void ext4_xattr_shift_entries(struct ext4_xattr_entry
*entry
,
1226 int value_offs_shift
, void *to
,
1227 void *from
, size_t n
, int blocksize
)
1229 struct ext4_xattr_entry
*last
= entry
;
1232 /* Adjust the value offsets of the entries */
1233 for (; !IS_LAST_ENTRY(last
); last
= EXT4_XATTR_NEXT(last
)) {
1234 if (!last
->e_value_block
&& last
->e_value_size
) {
1235 new_offs
= le16_to_cpu(last
->e_value_offs
) +
1237 BUG_ON(new_offs
+ le32_to_cpu(last
->e_value_size
)
1239 last
->e_value_offs
= cpu_to_le16(new_offs
);
1242 /* Shift the entries by n bytes */
1243 memmove(to
, from
, n
);
1247 * Expand an inode by new_extra_isize bytes when EAs are present.
1248 * Returns 0 on success or negative error number on failure.
1250 int ext4_expand_extra_isize_ea(struct inode
*inode
, int new_extra_isize
,
1251 struct ext4_inode
*raw_inode
, handle_t
*handle
)
1253 struct ext4_xattr_ibody_header
*header
;
1254 struct ext4_xattr_entry
*entry
, *last
, *first
;
1255 struct buffer_head
*bh
= NULL
;
1256 struct ext4_xattr_ibody_find
*is
= NULL
;
1257 struct ext4_xattr_block_find
*bs
= NULL
;
1258 char *buffer
= NULL
, *b_entry_name
= NULL
;
1259 size_t min_offs
, free
;
1261 void *base
, *start
, *end
;
1262 int extra_isize
= 0, error
= 0, tried_min_extra_isize
= 0;
1263 int s_min_extra_isize
= le16_to_cpu(EXT4_SB(inode
->i_sb
)->s_es
->s_min_extra_isize
);
1265 down_write(&EXT4_I(inode
)->xattr_sem
);
1267 if (EXT4_I(inode
)->i_extra_isize
>= new_extra_isize
) {
1268 up_write(&EXT4_I(inode
)->xattr_sem
);
1272 header
= IHDR(inode
, raw_inode
);
1273 entry
= IFIRST(header
);
1276 * Check if enough free space is available in the inode to shift the
1277 * entries ahead by new_extra_isize.
1280 base
= start
= entry
;
1281 end
= (void *)raw_inode
+ EXT4_SB(inode
->i_sb
)->s_inode_size
;
1282 min_offs
= end
- base
;
1284 total_ino
= sizeof(struct ext4_xattr_ibody_header
);
1286 free
= ext4_xattr_free_space(last
, &min_offs
, base
, &total_ino
);
1287 if (free
>= new_extra_isize
) {
1288 entry
= IFIRST(header
);
1289 ext4_xattr_shift_entries(entry
, EXT4_I(inode
)->i_extra_isize
1290 - new_extra_isize
, (void *)raw_inode
+
1291 EXT4_GOOD_OLD_INODE_SIZE
+ new_extra_isize
,
1292 (void *)header
, total_ino
,
1293 inode
->i_sb
->s_blocksize
);
1294 EXT4_I(inode
)->i_extra_isize
= new_extra_isize
;
1300 * Enough free space isn't available in the inode, check if
1301 * EA block can hold new_extra_isize bytes.
1303 if (EXT4_I(inode
)->i_file_acl
) {
1304 bh
= sb_bread(inode
->i_sb
, EXT4_I(inode
)->i_file_acl
);
1308 if (ext4_xattr_check_block(inode
, bh
)) {
1309 EXT4_ERROR_INODE(inode
, "bad block %llu",
1310 EXT4_I(inode
)->i_file_acl
);
1316 end
= bh
->b_data
+ bh
->b_size
;
1317 min_offs
= end
- base
;
1318 free
= ext4_xattr_free_space(first
, &min_offs
, base
, NULL
);
1319 if (free
< new_extra_isize
) {
1320 if (!tried_min_extra_isize
&& s_min_extra_isize
) {
1321 tried_min_extra_isize
++;
1322 new_extra_isize
= s_min_extra_isize
;
1330 free
= inode
->i_sb
->s_blocksize
;
1333 while (new_extra_isize
> 0) {
1334 size_t offs
, size
, entry_size
;
1335 struct ext4_xattr_entry
*small_entry
= NULL
;
1336 struct ext4_xattr_info i
= {
1340 unsigned int total_size
; /* EA entry size + value size */
1341 unsigned int shift_bytes
; /* No. of bytes to shift EAs by? */
1342 unsigned int min_total_size
= ~0U;
1344 is
= kzalloc(sizeof(struct ext4_xattr_ibody_find
), GFP_NOFS
);
1345 bs
= kzalloc(sizeof(struct ext4_xattr_block_find
), GFP_NOFS
);
1351 is
->s
.not_found
= -ENODATA
;
1352 bs
->s
.not_found
= -ENODATA
;
1356 last
= IFIRST(header
);
1357 /* Find the entry best suited to be pushed into EA block */
1359 for (; !IS_LAST_ENTRY(last
); last
= EXT4_XATTR_NEXT(last
)) {
1361 EXT4_XATTR_SIZE(le32_to_cpu(last
->e_value_size
)) +
1362 EXT4_XATTR_LEN(last
->e_name_len
);
1363 if (total_size
<= free
&& total_size
< min_total_size
) {
1364 if (total_size
< new_extra_isize
) {
1368 min_total_size
= total_size
;
1373 if (entry
== NULL
) {
1375 entry
= small_entry
;
1377 if (!tried_min_extra_isize
&&
1378 s_min_extra_isize
) {
1379 tried_min_extra_isize
++;
1380 new_extra_isize
= s_min_extra_isize
;
1381 kfree(is
); is
= NULL
;
1382 kfree(bs
); bs
= NULL
;
1390 offs
= le16_to_cpu(entry
->e_value_offs
);
1391 size
= le32_to_cpu(entry
->e_value_size
);
1392 entry_size
= EXT4_XATTR_LEN(entry
->e_name_len
);
1393 i
.name_index
= entry
->e_name_index
,
1394 buffer
= kmalloc(EXT4_XATTR_SIZE(size
), GFP_NOFS
);
1395 b_entry_name
= kmalloc(entry
->e_name_len
+ 1, GFP_NOFS
);
1396 if (!buffer
|| !b_entry_name
) {
1400 /* Save the entry name and the entry value */
1401 memcpy(buffer
, (void *)IFIRST(header
) + offs
,
1402 EXT4_XATTR_SIZE(size
));
1403 memcpy(b_entry_name
, entry
->e_name
, entry
->e_name_len
);
1404 b_entry_name
[entry
->e_name_len
] = '\0';
1405 i
.name
= b_entry_name
;
1407 error
= ext4_get_inode_loc(inode
, &is
->iloc
);
1411 error
= ext4_xattr_ibody_find(inode
, &i
, is
);
1415 /* Remove the chosen entry from the inode */
1416 error
= ext4_xattr_ibody_set(handle
, inode
, &i
, is
);
1420 entry
= IFIRST(header
);
1421 if (entry_size
+ EXT4_XATTR_SIZE(size
) >= new_extra_isize
)
1422 shift_bytes
= new_extra_isize
;
1424 shift_bytes
= entry_size
+ size
;
1425 /* Adjust the offsets and shift the remaining entries ahead */
1426 ext4_xattr_shift_entries(entry
, EXT4_I(inode
)->i_extra_isize
-
1427 shift_bytes
, (void *)raw_inode
+
1428 EXT4_GOOD_OLD_INODE_SIZE
+ extra_isize
+ shift_bytes
,
1429 (void *)header
, total_ino
- entry_size
,
1430 inode
->i_sb
->s_blocksize
);
1432 extra_isize
+= shift_bytes
;
1433 new_extra_isize
-= shift_bytes
;
1434 EXT4_I(inode
)->i_extra_isize
= extra_isize
;
1436 i
.name
= b_entry_name
;
1439 error
= ext4_xattr_block_find(inode
, &i
, bs
);
1443 /* Add entry which was removed from the inode into the block */
1444 error
= ext4_xattr_block_set(handle
, inode
, &i
, bs
);
1447 kfree(b_entry_name
);
1449 b_entry_name
= NULL
;
1451 brelse(is
->iloc
.bh
);
1456 up_write(&EXT4_I(inode
)->xattr_sem
);
1460 kfree(b_entry_name
);
1463 brelse(is
->iloc
.bh
);
1467 up_write(&EXT4_I(inode
)->xattr_sem
);
1474 * ext4_xattr_delete_inode()
1476 * Free extended attribute resources associated with this inode. This
1477 * is called immediately before an inode is freed. We have exclusive
1478 * access to the inode.
1481 ext4_xattr_delete_inode(handle_t
*handle
, struct inode
*inode
)
1483 struct buffer_head
*bh
= NULL
;
1485 if (!EXT4_I(inode
)->i_file_acl
)
1487 bh
= sb_bread(inode
->i_sb
, EXT4_I(inode
)->i_file_acl
);
1489 EXT4_ERROR_INODE(inode
, "block %llu read error",
1490 EXT4_I(inode
)->i_file_acl
);
1493 if (BHDR(bh
)->h_magic
!= cpu_to_le32(EXT4_XATTR_MAGIC
) ||
1494 BHDR(bh
)->h_blocks
!= cpu_to_le32(1)) {
1495 EXT4_ERROR_INODE(inode
, "bad block %llu",
1496 EXT4_I(inode
)->i_file_acl
);
1499 ext4_xattr_release_block(handle
, inode
, bh
);
1500 EXT4_I(inode
)->i_file_acl
= 0;
1507 * ext4_xattr_put_super()
1509 * This is called when a file system is unmounted.
1512 ext4_xattr_put_super(struct super_block
*sb
)
1514 mb_cache_shrink(sb
->s_bdev
);
1518 * ext4_xattr_cache_insert()
1520 * Create a new entry in the extended attribute cache, and insert
1521 * it unless such an entry is already in the cache.
1523 * Returns 0, or a negative error number on failure.
1526 ext4_xattr_cache_insert(struct mb_cache
*ext4_mb_cache
, struct buffer_head
*bh
)
1528 __u32 hash
= le32_to_cpu(BHDR(bh
)->h_hash
);
1529 struct mb_cache_entry
*ce
;
1532 ce
= mb_cache_entry_alloc(ext4_mb_cache
, GFP_NOFS
);
1534 ea_bdebug(bh
, "out of memory");
1537 error
= mb_cache_entry_insert(ce
, bh
->b_bdev
, bh
->b_blocknr
, hash
);
1539 mb_cache_entry_free(ce
);
1540 if (error
== -EBUSY
) {
1541 ea_bdebug(bh
, "already in cache");
1545 ea_bdebug(bh
, "inserting [%x]", (int)hash
);
1546 mb_cache_entry_release(ce
);
1553 * Compare two extended attribute blocks for equality.
1555 * Returns 0 if the blocks are equal, 1 if they differ, and
1556 * a negative error number on errors.
1559 ext4_xattr_cmp(struct ext4_xattr_header
*header1
,
1560 struct ext4_xattr_header
*header2
)
1562 struct ext4_xattr_entry
*entry1
, *entry2
;
1564 entry1
= ENTRY(header1
+1);
1565 entry2
= ENTRY(header2
+1);
1566 while (!IS_LAST_ENTRY(entry1
)) {
1567 if (IS_LAST_ENTRY(entry2
))
1569 if (entry1
->e_hash
!= entry2
->e_hash
||
1570 entry1
->e_name_index
!= entry2
->e_name_index
||
1571 entry1
->e_name_len
!= entry2
->e_name_len
||
1572 entry1
->e_value_size
!= entry2
->e_value_size
||
1573 memcmp(entry1
->e_name
, entry2
->e_name
, entry1
->e_name_len
))
1575 if (entry1
->e_value_block
!= 0 || entry2
->e_value_block
!= 0)
1577 if (memcmp((char *)header1
+ le16_to_cpu(entry1
->e_value_offs
),
1578 (char *)header2
+ le16_to_cpu(entry2
->e_value_offs
),
1579 le32_to_cpu(entry1
->e_value_size
)))
1582 entry1
= EXT4_XATTR_NEXT(entry1
);
1583 entry2
= EXT4_XATTR_NEXT(entry2
);
1585 if (!IS_LAST_ENTRY(entry2
))
1591 * ext4_xattr_cache_find()
1593 * Find an identical extended attribute block.
1595 * Returns a pointer to the block found, or NULL if such a block was
1596 * not found or an error occurred.
1598 static struct buffer_head
*
1599 ext4_xattr_cache_find(struct inode
*inode
, struct ext4_xattr_header
*header
,
1600 struct mb_cache_entry
**pce
)
1602 __u32 hash
= le32_to_cpu(header
->h_hash
);
1603 struct mb_cache_entry
*ce
;
1604 struct mb_cache
*ext4_mb_cache
= EXT4_GET_MB_CACHE(inode
);
1606 if (!header
->h_hash
)
1607 return NULL
; /* never share */
1608 ea_idebug(inode
, "looking for cached blocks [%x]", (int)hash
);
1610 ce
= mb_cache_entry_find_first(ext4_mb_cache
, inode
->i_sb
->s_bdev
,
1613 struct buffer_head
*bh
;
1616 if (PTR_ERR(ce
) == -EAGAIN
)
1620 bh
= sb_bread(inode
->i_sb
, ce
->e_block
);
1622 EXT4_ERROR_INODE(inode
, "block %lu read error",
1623 (unsigned long) ce
->e_block
);
1624 } else if (le32_to_cpu(BHDR(bh
)->h_refcount
) >=
1625 EXT4_XATTR_REFCOUNT_MAX
) {
1626 ea_idebug(inode
, "block %lu refcount %d>=%d",
1627 (unsigned long) ce
->e_block
,
1628 le32_to_cpu(BHDR(bh
)->h_refcount
),
1629 EXT4_XATTR_REFCOUNT_MAX
);
1630 } else if (ext4_xattr_cmp(header
, BHDR(bh
)) == 0) {
1635 ce
= mb_cache_entry_find_next(ce
, inode
->i_sb
->s_bdev
, hash
);
1640 #define NAME_HASH_SHIFT 5
1641 #define VALUE_HASH_SHIFT 16
1644 * ext4_xattr_hash_entry()
1646 * Compute the hash of an extended attribute.
1648 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header
*header
,
1649 struct ext4_xattr_entry
*entry
)
1652 char *name
= entry
->e_name
;
1655 for (n
= 0; n
< entry
->e_name_len
; n
++) {
1656 hash
= (hash
<< NAME_HASH_SHIFT
) ^
1657 (hash
>> (8*sizeof(hash
) - NAME_HASH_SHIFT
)) ^
1661 if (entry
->e_value_block
== 0 && entry
->e_value_size
!= 0) {
1662 __le32
*value
= (__le32
*)((char *)header
+
1663 le16_to_cpu(entry
->e_value_offs
));
1664 for (n
= (le32_to_cpu(entry
->e_value_size
) +
1665 EXT4_XATTR_ROUND
) >> EXT4_XATTR_PAD_BITS
; n
; n
--) {
1666 hash
= (hash
<< VALUE_HASH_SHIFT
) ^
1667 (hash
>> (8*sizeof(hash
) - VALUE_HASH_SHIFT
)) ^
1668 le32_to_cpu(*value
++);
1671 entry
->e_hash
= cpu_to_le32(hash
);
1674 #undef NAME_HASH_SHIFT
1675 #undef VALUE_HASH_SHIFT
1677 #define BLOCK_HASH_SHIFT 16
1680 * ext4_xattr_rehash()
1682 * Re-compute the extended attribute hash value after an entry has changed.
1684 static void ext4_xattr_rehash(struct ext4_xattr_header
*header
,
1685 struct ext4_xattr_entry
*entry
)
1687 struct ext4_xattr_entry
*here
;
1690 ext4_xattr_hash_entry(header
, entry
);
1691 here
= ENTRY(header
+1);
1692 while (!IS_LAST_ENTRY(here
)) {
1693 if (!here
->e_hash
) {
1694 /* Block is not shared if an entry's hash value == 0 */
1698 hash
= (hash
<< BLOCK_HASH_SHIFT
) ^
1699 (hash
>> (8*sizeof(hash
) - BLOCK_HASH_SHIFT
)) ^
1700 le32_to_cpu(here
->e_hash
);
1701 here
= EXT4_XATTR_NEXT(here
);
1703 header
->h_hash
= cpu_to_le32(hash
);
1706 #undef BLOCK_HASH_SHIFT
1708 #define HASH_BUCKET_BITS 10
1711 ext4_xattr_create_cache(char *name
)
1713 return mb_cache_create(name
, HASH_BUCKET_BITS
);
1716 void ext4_xattr_destroy_cache(struct mb_cache
*cache
)
1719 mb_cache_destroy(cache
);