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/ext4_jbd2.h>
57 #include <linux/ext4_fs.h>
58 #include <linux/mbcache.h>
59 #include <linux/quotaops.h>
60 #include <linux/rwsem.h>
64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
69 #ifdef EXT4_XATTR_DEBUG
70 # define ea_idebug(inode, f...) do { \
71 printk(KERN_DEBUG "inode %s:%lu: ", \
72 inode->i_sb->s_id, inode->i_ino); \
76 # define ea_bdebug(bh, f...) do { \
77 char b[BDEVNAME_SIZE]; \
78 printk(KERN_DEBUG "block %s:%lu: ", \
79 bdevname(bh->b_bdev, b), \
80 (unsigned long) bh->b_blocknr); \
85 # define ea_idebug(f...)
86 # define ea_bdebug(f...)
89 static void ext4_xattr_cache_insert(struct buffer_head
*);
90 static struct buffer_head
*ext4_xattr_cache_find(struct inode
*,
91 struct ext4_xattr_header
*,
92 struct mb_cache_entry
**);
93 static void ext4_xattr_rehash(struct ext4_xattr_header
*,
94 struct ext4_xattr_entry
*);
96 static struct mb_cache
*ext4_xattr_cache
;
98 static struct xattr_handler
*ext4_xattr_handler_map
[] = {
99 [EXT4_XATTR_INDEX_USER
] = &ext4_xattr_user_handler
,
100 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
101 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS
] = &ext4_xattr_acl_access_handler
,
102 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT
] = &ext4_xattr_acl_default_handler
,
104 [EXT4_XATTR_INDEX_TRUSTED
] = &ext4_xattr_trusted_handler
,
105 #ifdef CONFIG_EXT4DEV_FS_SECURITY
106 [EXT4_XATTR_INDEX_SECURITY
] = &ext4_xattr_security_handler
,
110 struct xattr_handler
*ext4_xattr_handlers
[] = {
111 &ext4_xattr_user_handler
,
112 &ext4_xattr_trusted_handler
,
113 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
114 &ext4_xattr_acl_access_handler
,
115 &ext4_xattr_acl_default_handler
,
117 #ifdef CONFIG_EXT4DEV_FS_SECURITY
118 &ext4_xattr_security_handler
,
123 static inline struct xattr_handler
*
124 ext4_xattr_handler(int name_index
)
126 struct xattr_handler
*handler
= NULL
;
128 if (name_index
> 0 && name_index
< ARRAY_SIZE(ext4_xattr_handler_map
))
129 handler
= ext4_xattr_handler_map
[name_index
];
134 * Inode operation listxattr()
136 * dentry->d_inode->i_mutex: don't care
139 ext4_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
141 return ext4_xattr_list(dentry
->d_inode
, buffer
, size
);
145 ext4_xattr_check_names(struct ext4_xattr_entry
*entry
, void *end
)
147 while (!IS_LAST_ENTRY(entry
)) {
148 struct ext4_xattr_entry
*next
= EXT4_XATTR_NEXT(entry
);
149 if ((void *)next
>= end
)
157 ext4_xattr_check_block(struct buffer_head
*bh
)
161 if (BHDR(bh
)->h_magic
!= cpu_to_le32(EXT4_XATTR_MAGIC
) ||
162 BHDR(bh
)->h_blocks
!= cpu_to_le32(1))
164 error
= ext4_xattr_check_names(BFIRST(bh
), bh
->b_data
+ bh
->b_size
);
169 ext4_xattr_check_entry(struct ext4_xattr_entry
*entry
, size_t size
)
171 size_t value_size
= le32_to_cpu(entry
->e_value_size
);
173 if (entry
->e_value_block
!= 0 || value_size
> size
||
174 le16_to_cpu(entry
->e_value_offs
) + value_size
> size
)
180 ext4_xattr_find_entry(struct ext4_xattr_entry
**pentry
, int name_index
,
181 const char *name
, size_t size
, int sorted
)
183 struct ext4_xattr_entry
*entry
;
189 name_len
= strlen(name
);
191 for (; !IS_LAST_ENTRY(entry
); entry
= EXT4_XATTR_NEXT(entry
)) {
192 cmp
= name_index
- entry
->e_name_index
;
194 cmp
= name_len
- entry
->e_name_len
;
196 cmp
= memcmp(name
, entry
->e_name
, name_len
);
197 if (cmp
<= 0 && (sorted
|| cmp
== 0))
201 if (!cmp
&& ext4_xattr_check_entry(entry
, size
))
203 return cmp
? -ENODATA
: 0;
207 ext4_xattr_block_get(struct inode
*inode
, int name_index
, const char *name
,
208 void *buffer
, size_t buffer_size
)
210 struct buffer_head
*bh
= NULL
;
211 struct ext4_xattr_entry
*entry
;
215 ea_idebug(inode
, "name=%d.%s, buffer=%p, buffer_size=%ld",
216 name_index
, name
, buffer
, (long)buffer_size
);
219 if (!EXT4_I(inode
)->i_file_acl
)
221 ea_idebug(inode
, "reading block %u", EXT4_I(inode
)->i_file_acl
);
222 bh
= sb_bread(inode
->i_sb
, EXT4_I(inode
)->i_file_acl
);
225 ea_bdebug(bh
, "b_count=%d, refcount=%d",
226 atomic_read(&(bh
->b_count
)), le32_to_cpu(BHDR(bh
)->h_refcount
));
227 if (ext4_xattr_check_block(bh
)) {
228 bad_block
: ext4_error(inode
->i_sb
, __FUNCTION__
,
229 "inode %lu: bad block %llu", inode
->i_ino
,
230 EXT4_I(inode
)->i_file_acl
);
234 ext4_xattr_cache_insert(bh
);
236 error
= ext4_xattr_find_entry(&entry
, name_index
, name
, bh
->b_size
, 1);
241 size
= le32_to_cpu(entry
->e_value_size
);
244 if (size
> buffer_size
)
246 memcpy(buffer
, bh
->b_data
+ le16_to_cpu(entry
->e_value_offs
),
257 ext4_xattr_ibody_get(struct inode
*inode
, int name_index
, const char *name
,
258 void *buffer
, size_t buffer_size
)
260 struct ext4_xattr_ibody_header
*header
;
261 struct ext4_xattr_entry
*entry
;
262 struct ext4_inode
*raw_inode
;
263 struct ext4_iloc iloc
;
268 if (!(EXT4_I(inode
)->i_state
& EXT4_STATE_XATTR
))
270 error
= ext4_get_inode_loc(inode
, &iloc
);
273 raw_inode
= ext4_raw_inode(&iloc
);
274 header
= IHDR(inode
, raw_inode
);
275 entry
= IFIRST(header
);
276 end
= (void *)raw_inode
+ EXT4_SB(inode
->i_sb
)->s_inode_size
;
277 error
= ext4_xattr_check_names(entry
, end
);
280 error
= ext4_xattr_find_entry(&entry
, name_index
, name
,
281 end
- (void *)entry
, 0);
284 size
= le32_to_cpu(entry
->e_value_size
);
287 if (size
> buffer_size
)
289 memcpy(buffer
, (void *)IFIRST(header
) +
290 le16_to_cpu(entry
->e_value_offs
), size
);
302 * Copy an extended attribute into the buffer
303 * provided, or compute the buffer size required.
304 * Buffer is NULL to compute the size of the buffer required.
306 * Returns a negative error number on failure, or the number of bytes
307 * used / required on success.
310 ext4_xattr_get(struct inode
*inode
, int name_index
, const char *name
,
311 void *buffer
, size_t buffer_size
)
315 down_read(&EXT4_I(inode
)->xattr_sem
);
316 error
= ext4_xattr_ibody_get(inode
, name_index
, name
, buffer
,
318 if (error
== -ENODATA
)
319 error
= ext4_xattr_block_get(inode
, name_index
, name
, buffer
,
321 up_read(&EXT4_I(inode
)->xattr_sem
);
326 ext4_xattr_list_entries(struct inode
*inode
, struct ext4_xattr_entry
*entry
,
327 char *buffer
, size_t buffer_size
)
329 size_t rest
= buffer_size
;
331 for (; !IS_LAST_ENTRY(entry
); entry
= EXT4_XATTR_NEXT(entry
)) {
332 struct xattr_handler
*handler
=
333 ext4_xattr_handler(entry
->e_name_index
);
336 size_t size
= handler
->list(inode
, buffer
, rest
,
347 return buffer_size
- rest
;
351 ext4_xattr_block_list(struct inode
*inode
, char *buffer
, size_t buffer_size
)
353 struct buffer_head
*bh
= NULL
;
356 ea_idebug(inode
, "buffer=%p, buffer_size=%ld",
357 buffer
, (long)buffer_size
);
360 if (!EXT4_I(inode
)->i_file_acl
)
362 ea_idebug(inode
, "reading block %u", EXT4_I(inode
)->i_file_acl
);
363 bh
= sb_bread(inode
->i_sb
, EXT4_I(inode
)->i_file_acl
);
367 ea_bdebug(bh
, "b_count=%d, refcount=%d",
368 atomic_read(&(bh
->b_count
)), le32_to_cpu(BHDR(bh
)->h_refcount
));
369 if (ext4_xattr_check_block(bh
)) {
370 ext4_error(inode
->i_sb
, __FUNCTION__
,
371 "inode %lu: bad block %llu", inode
->i_ino
,
372 EXT4_I(inode
)->i_file_acl
);
376 ext4_xattr_cache_insert(bh
);
377 error
= ext4_xattr_list_entries(inode
, BFIRST(bh
), buffer
, buffer_size
);
386 ext4_xattr_ibody_list(struct inode
*inode
, char *buffer
, size_t buffer_size
)
388 struct ext4_xattr_ibody_header
*header
;
389 struct ext4_inode
*raw_inode
;
390 struct ext4_iloc iloc
;
394 if (!(EXT4_I(inode
)->i_state
& EXT4_STATE_XATTR
))
396 error
= ext4_get_inode_loc(inode
, &iloc
);
399 raw_inode
= ext4_raw_inode(&iloc
);
400 header
= IHDR(inode
, raw_inode
);
401 end
= (void *)raw_inode
+ EXT4_SB(inode
->i_sb
)->s_inode_size
;
402 error
= ext4_xattr_check_names(IFIRST(header
), end
);
405 error
= ext4_xattr_list_entries(inode
, IFIRST(header
),
406 buffer
, buffer_size
);
416 * Copy a list of attribute names into the buffer
417 * provided, or compute the buffer size required.
418 * Buffer is NULL to compute the size of the buffer required.
420 * Returns a negative error number on failure, or the number of bytes
421 * used / required on success.
424 ext4_xattr_list(struct inode
*inode
, char *buffer
, size_t buffer_size
)
426 int i_error
, b_error
;
428 down_read(&EXT4_I(inode
)->xattr_sem
);
429 i_error
= ext4_xattr_ibody_list(inode
, buffer
, buffer_size
);
435 buffer_size
-= i_error
;
437 b_error
= ext4_xattr_block_list(inode
, buffer
, buffer_size
);
441 up_read(&EXT4_I(inode
)->xattr_sem
);
442 return i_error
+ b_error
;
446 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
449 static void ext4_xattr_update_super_block(handle_t
*handle
,
450 struct super_block
*sb
)
452 if (EXT4_HAS_COMPAT_FEATURE(sb
, EXT4_FEATURE_COMPAT_EXT_ATTR
))
455 if (ext4_journal_get_write_access(handle
, EXT4_SB(sb
)->s_sbh
) == 0) {
456 EXT4_SET_COMPAT_FEATURE(sb
, EXT4_FEATURE_COMPAT_EXT_ATTR
);
458 ext4_journal_dirty_metadata(handle
, EXT4_SB(sb
)->s_sbh
);
463 * Release the xattr block BH: If the reference count is > 1, decrement
464 * it; otherwise free the block.
467 ext4_xattr_release_block(handle_t
*handle
, struct inode
*inode
,
468 struct buffer_head
*bh
)
470 struct mb_cache_entry
*ce
= NULL
;
473 ce
= mb_cache_entry_get(ext4_xattr_cache
, bh
->b_bdev
, bh
->b_blocknr
);
474 error
= ext4_journal_get_write_access(handle
, bh
);
479 if (BHDR(bh
)->h_refcount
== cpu_to_le32(1)) {
480 ea_bdebug(bh
, "refcount now=0; freeing");
482 mb_cache_entry_free(ce
);
483 ext4_free_blocks(handle
, inode
, bh
->b_blocknr
, 1);
485 ext4_forget(handle
, 1, inode
, bh
, bh
->b_blocknr
);
487 BHDR(bh
)->h_refcount
= cpu_to_le32(
488 le32_to_cpu(BHDR(bh
)->h_refcount
) - 1);
489 error
= ext4_journal_dirty_metadata(handle
, bh
);
492 DQUOT_FREE_BLOCK(inode
, 1);
493 ea_bdebug(bh
, "refcount now=%d; releasing",
494 le32_to_cpu(BHDR(bh
)->h_refcount
));
496 mb_cache_entry_release(ce
);
500 ext4_std_error(inode
->i_sb
, error
);
505 * Find the available free space for EAs. This also returns the total number of
506 * bytes used by EA entries.
508 static size_t ext4_xattr_free_space(struct ext4_xattr_entry
*last
,
509 size_t *min_offs
, void *base
, int *total
)
511 for (; !IS_LAST_ENTRY(last
); last
= EXT4_XATTR_NEXT(last
)) {
512 *total
+= EXT4_XATTR_LEN(last
->e_name_len
);
513 if (!last
->e_value_block
&& last
->e_value_size
) {
514 size_t offs
= le16_to_cpu(last
->e_value_offs
);
515 if (offs
< *min_offs
)
519 return (*min_offs
- ((void *)last
- base
) - sizeof(__u32
));
522 struct ext4_xattr_info
{
529 struct ext4_xattr_search
{
530 struct ext4_xattr_entry
*first
;
533 struct ext4_xattr_entry
*here
;
538 ext4_xattr_set_entry(struct ext4_xattr_info
*i
, struct ext4_xattr_search
*s
)
540 struct ext4_xattr_entry
*last
;
541 size_t free
, min_offs
= s
->end
- s
->base
, name_len
= strlen(i
->name
);
543 /* Compute min_offs and last. */
545 for (; !IS_LAST_ENTRY(last
); last
= EXT4_XATTR_NEXT(last
)) {
546 if (!last
->e_value_block
&& last
->e_value_size
) {
547 size_t offs
= le16_to_cpu(last
->e_value_offs
);
552 free
= min_offs
- ((void *)last
- s
->base
) - sizeof(__u32
);
554 if (!s
->here
->e_value_block
&& s
->here
->e_value_size
) {
555 size_t size
= le32_to_cpu(s
->here
->e_value_size
);
556 free
+= EXT4_XATTR_SIZE(size
);
558 free
+= EXT4_XATTR_LEN(name_len
);
561 if (free
< EXT4_XATTR_SIZE(i
->value_len
) ||
562 free
< EXT4_XATTR_LEN(name_len
) +
563 EXT4_XATTR_SIZE(i
->value_len
))
567 if (i
->value
&& s
->not_found
) {
568 /* Insert the new name. */
569 size_t size
= EXT4_XATTR_LEN(name_len
);
570 size_t rest
= (void *)last
- (void *)s
->here
+ sizeof(__u32
);
571 memmove((void *)s
->here
+ size
, s
->here
, rest
);
572 memset(s
->here
, 0, size
);
573 s
->here
->e_name_index
= i
->name_index
;
574 s
->here
->e_name_len
= name_len
;
575 memcpy(s
->here
->e_name
, i
->name
, name_len
);
577 if (!s
->here
->e_value_block
&& s
->here
->e_value_size
) {
578 void *first_val
= s
->base
+ min_offs
;
579 size_t offs
= le16_to_cpu(s
->here
->e_value_offs
);
580 void *val
= s
->base
+ offs
;
581 size_t size
= EXT4_XATTR_SIZE(
582 le32_to_cpu(s
->here
->e_value_size
));
584 if (i
->value
&& size
== EXT4_XATTR_SIZE(i
->value_len
)) {
585 /* The old and the new value have the same
586 size. Just replace. */
587 s
->here
->e_value_size
=
588 cpu_to_le32(i
->value_len
);
589 memset(val
+ size
- EXT4_XATTR_PAD
, 0,
590 EXT4_XATTR_PAD
); /* Clear pad bytes. */
591 memcpy(val
, i
->value
, i
->value_len
);
595 /* Remove the old value. */
596 memmove(first_val
+ size
, first_val
, val
- first_val
);
597 memset(first_val
, 0, size
);
598 s
->here
->e_value_size
= 0;
599 s
->here
->e_value_offs
= 0;
602 /* Adjust all value offsets. */
604 while (!IS_LAST_ENTRY(last
)) {
605 size_t o
= le16_to_cpu(last
->e_value_offs
);
606 if (!last
->e_value_block
&&
607 last
->e_value_size
&& o
< offs
)
609 cpu_to_le16(o
+ size
);
610 last
= EXT4_XATTR_NEXT(last
);
614 /* Remove the old name. */
615 size_t size
= EXT4_XATTR_LEN(name_len
);
616 last
= ENTRY((void *)last
- size
);
617 memmove(s
->here
, (void *)s
->here
+ size
,
618 (void *)last
- (void *)s
->here
+ sizeof(__u32
));
619 memset(last
, 0, size
);
624 /* Insert the new value. */
625 s
->here
->e_value_size
= cpu_to_le32(i
->value_len
);
627 size_t size
= EXT4_XATTR_SIZE(i
->value_len
);
628 void *val
= s
->base
+ min_offs
- size
;
629 s
->here
->e_value_offs
= cpu_to_le16(min_offs
- size
);
630 memset(val
+ size
- EXT4_XATTR_PAD
, 0,
631 EXT4_XATTR_PAD
); /* Clear the pad bytes. */
632 memcpy(val
, i
->value
, i
->value_len
);
638 struct ext4_xattr_block_find
{
639 struct ext4_xattr_search s
;
640 struct buffer_head
*bh
;
644 ext4_xattr_block_find(struct inode
*inode
, struct ext4_xattr_info
*i
,
645 struct ext4_xattr_block_find
*bs
)
647 struct super_block
*sb
= inode
->i_sb
;
650 ea_idebug(inode
, "name=%d.%s, value=%p, value_len=%ld",
651 i
->name_index
, i
->name
, i
->value
, (long)i
->value_len
);
653 if (EXT4_I(inode
)->i_file_acl
) {
654 /* The inode already has an extended attribute block. */
655 bs
->bh
= sb_bread(sb
, EXT4_I(inode
)->i_file_acl
);
659 ea_bdebug(bs
->bh
, "b_count=%d, refcount=%d",
660 atomic_read(&(bs
->bh
->b_count
)),
661 le32_to_cpu(BHDR(bs
->bh
)->h_refcount
));
662 if (ext4_xattr_check_block(bs
->bh
)) {
663 ext4_error(sb
, __FUNCTION__
,
664 "inode %lu: bad block %llu", inode
->i_ino
,
665 EXT4_I(inode
)->i_file_acl
);
669 /* Find the named attribute. */
670 bs
->s
.base
= BHDR(bs
->bh
);
671 bs
->s
.first
= BFIRST(bs
->bh
);
672 bs
->s
.end
= bs
->bh
->b_data
+ bs
->bh
->b_size
;
673 bs
->s
.here
= bs
->s
.first
;
674 error
= ext4_xattr_find_entry(&bs
->s
.here
, i
->name_index
,
675 i
->name
, bs
->bh
->b_size
, 1);
676 if (error
&& error
!= -ENODATA
)
678 bs
->s
.not_found
= error
;
687 ext4_xattr_block_set(handle_t
*handle
, struct inode
*inode
,
688 struct ext4_xattr_info
*i
,
689 struct ext4_xattr_block_find
*bs
)
691 struct super_block
*sb
= inode
->i_sb
;
692 struct buffer_head
*new_bh
= NULL
;
693 struct ext4_xattr_search
*s
= &bs
->s
;
694 struct mb_cache_entry
*ce
= NULL
;
697 #define header(x) ((struct ext4_xattr_header *)(x))
699 if (i
->value
&& i
->value_len
> sb
->s_blocksize
)
702 ce
= mb_cache_entry_get(ext4_xattr_cache
, bs
->bh
->b_bdev
,
704 error
= ext4_journal_get_write_access(handle
, bs
->bh
);
709 if (header(s
->base
)->h_refcount
== cpu_to_le32(1)) {
711 mb_cache_entry_free(ce
);
714 ea_bdebug(bs
->bh
, "modifying in-place");
715 error
= ext4_xattr_set_entry(i
, s
);
717 if (!IS_LAST_ENTRY(s
->first
))
718 ext4_xattr_rehash(header(s
->base
),
720 ext4_xattr_cache_insert(bs
->bh
);
722 unlock_buffer(bs
->bh
);
726 error
= ext4_journal_dirty_metadata(handle
,
732 int offset
= (char *)s
->here
- bs
->bh
->b_data
;
734 unlock_buffer(bs
->bh
);
735 jbd2_journal_release_buffer(handle
, bs
->bh
);
737 mb_cache_entry_release(ce
);
740 ea_bdebug(bs
->bh
, "cloning");
741 s
->base
= kmalloc(bs
->bh
->b_size
, GFP_KERNEL
);
745 memcpy(s
->base
, BHDR(bs
->bh
), bs
->bh
->b_size
);
746 s
->first
= ENTRY(header(s
->base
)+1);
747 header(s
->base
)->h_refcount
= cpu_to_le32(1);
748 s
->here
= ENTRY(s
->base
+ offset
);
749 s
->end
= s
->base
+ bs
->bh
->b_size
;
752 /* Allocate a buffer where we construct the new block. */
753 s
->base
= kzalloc(sb
->s_blocksize
, GFP_KERNEL
);
754 /* assert(header == s->base) */
758 header(s
->base
)->h_magic
= cpu_to_le32(EXT4_XATTR_MAGIC
);
759 header(s
->base
)->h_blocks
= cpu_to_le32(1);
760 header(s
->base
)->h_refcount
= cpu_to_le32(1);
761 s
->first
= ENTRY(header(s
->base
)+1);
762 s
->here
= ENTRY(header(s
->base
)+1);
763 s
->end
= s
->base
+ sb
->s_blocksize
;
766 error
= ext4_xattr_set_entry(i
, s
);
771 if (!IS_LAST_ENTRY(s
->first
))
772 ext4_xattr_rehash(header(s
->base
), s
->here
);
775 if (!IS_LAST_ENTRY(s
->first
)) {
776 new_bh
= ext4_xattr_cache_find(inode
, header(s
->base
), &ce
);
778 /* We found an identical block in the cache. */
779 if (new_bh
== bs
->bh
)
780 ea_bdebug(new_bh
, "keeping");
782 /* The old block is released after updating
785 if (DQUOT_ALLOC_BLOCK(inode
, 1))
787 error
= ext4_journal_get_write_access(handle
,
792 BHDR(new_bh
)->h_refcount
= cpu_to_le32(1 +
793 le32_to_cpu(BHDR(new_bh
)->h_refcount
));
794 ea_bdebug(new_bh
, "reusing; refcount now=%d",
795 le32_to_cpu(BHDR(new_bh
)->h_refcount
));
796 unlock_buffer(new_bh
);
797 error
= ext4_journal_dirty_metadata(handle
,
802 mb_cache_entry_release(ce
);
804 } else if (bs
->bh
&& s
->base
== bs
->bh
->b_data
) {
805 /* We were modifying this block in-place. */
806 ea_bdebug(bs
->bh
, "keeping this block");
810 /* We need to allocate a new block */
811 ext4_fsblk_t goal
= le32_to_cpu(
812 EXT4_SB(sb
)->s_es
->s_first_data_block
) +
813 (ext4_fsblk_t
)EXT4_I(inode
)->i_block_group
*
814 EXT4_BLOCKS_PER_GROUP(sb
);
815 ext4_fsblk_t block
= ext4_new_block(handle
, inode
,
819 ea_idebug(inode
, "creating block %d", block
);
821 new_bh
= sb_getblk(sb
, block
);
824 ext4_free_blocks(handle
, inode
, block
, 1);
829 error
= ext4_journal_get_create_access(handle
, new_bh
);
831 unlock_buffer(new_bh
);
834 memcpy(new_bh
->b_data
, s
->base
, new_bh
->b_size
);
835 set_buffer_uptodate(new_bh
);
836 unlock_buffer(new_bh
);
837 ext4_xattr_cache_insert(new_bh
);
838 error
= ext4_journal_dirty_metadata(handle
, new_bh
);
844 /* Update the inode. */
845 EXT4_I(inode
)->i_file_acl
= new_bh
? new_bh
->b_blocknr
: 0;
847 /* Drop the previous xattr block. */
848 if (bs
->bh
&& bs
->bh
!= new_bh
)
849 ext4_xattr_release_block(handle
, inode
, bs
->bh
);
854 mb_cache_entry_release(ce
);
856 if (!(bs
->bh
&& s
->base
== bs
->bh
->b_data
))
862 DQUOT_FREE_BLOCK(inode
, 1);
866 ext4_error(inode
->i_sb
, __FUNCTION__
,
867 "inode %lu: bad block %llu", inode
->i_ino
,
868 EXT4_I(inode
)->i_file_acl
);
874 struct ext4_xattr_ibody_find
{
875 struct ext4_xattr_search s
;
876 struct ext4_iloc iloc
;
880 ext4_xattr_ibody_find(struct inode
*inode
, struct ext4_xattr_info
*i
,
881 struct ext4_xattr_ibody_find
*is
)
883 struct ext4_xattr_ibody_header
*header
;
884 struct ext4_inode
*raw_inode
;
887 if (EXT4_I(inode
)->i_extra_isize
== 0)
889 raw_inode
= ext4_raw_inode(&is
->iloc
);
890 header
= IHDR(inode
, raw_inode
);
891 is
->s
.base
= is
->s
.first
= IFIRST(header
);
892 is
->s
.here
= is
->s
.first
;
893 is
->s
.end
= (void *)raw_inode
+ EXT4_SB(inode
->i_sb
)->s_inode_size
;
894 if (EXT4_I(inode
)->i_state
& EXT4_STATE_XATTR
) {
895 error
= ext4_xattr_check_names(IFIRST(header
), is
->s
.end
);
898 /* Find the named attribute. */
899 error
= ext4_xattr_find_entry(&is
->s
.here
, i
->name_index
,
901 (void *)is
->s
.base
, 0);
902 if (error
&& error
!= -ENODATA
)
904 is
->s
.not_found
= error
;
910 ext4_xattr_ibody_set(handle_t
*handle
, struct inode
*inode
,
911 struct ext4_xattr_info
*i
,
912 struct ext4_xattr_ibody_find
*is
)
914 struct ext4_xattr_ibody_header
*header
;
915 struct ext4_xattr_search
*s
= &is
->s
;
918 if (EXT4_I(inode
)->i_extra_isize
== 0)
920 error
= ext4_xattr_set_entry(i
, s
);
923 header
= IHDR(inode
, ext4_raw_inode(&is
->iloc
));
924 if (!IS_LAST_ENTRY(s
->first
)) {
925 header
->h_magic
= cpu_to_le32(EXT4_XATTR_MAGIC
);
926 EXT4_I(inode
)->i_state
|= EXT4_STATE_XATTR
;
928 header
->h_magic
= cpu_to_le32(0);
929 EXT4_I(inode
)->i_state
&= ~EXT4_STATE_XATTR
;
935 * ext4_xattr_set_handle()
937 * Create, replace or remove an extended attribute for this inode. Buffer
938 * is NULL to remove an existing extended attribute, and non-NULL to
939 * either replace an existing extended attribute, or create a new extended
940 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
941 * specify that an extended attribute must exist and must not exist
942 * previous to the call, respectively.
944 * Returns 0, or a negative error number on failure.
947 ext4_xattr_set_handle(handle_t
*handle
, struct inode
*inode
, int name_index
,
948 const char *name
, const void *value
, size_t value_len
,
951 struct ext4_xattr_info i
= {
952 .name_index
= name_index
,
955 .value_len
= value_len
,
958 struct ext4_xattr_ibody_find is
= {
959 .s
= { .not_found
= -ENODATA
, },
961 struct ext4_xattr_block_find bs
= {
962 .s
= { .not_found
= -ENODATA
, },
968 if (strlen(name
) > 255)
970 down_write(&EXT4_I(inode
)->xattr_sem
);
971 error
= ext4_get_inode_loc(inode
, &is
.iloc
);
975 if (EXT4_I(inode
)->i_state
& EXT4_STATE_NEW
) {
976 struct ext4_inode
*raw_inode
= ext4_raw_inode(&is
.iloc
);
977 memset(raw_inode
, 0, EXT4_SB(inode
->i_sb
)->s_inode_size
);
978 EXT4_I(inode
)->i_state
&= ~EXT4_STATE_NEW
;
981 error
= ext4_xattr_ibody_find(inode
, &i
, &is
);
985 error
= ext4_xattr_block_find(inode
, &i
, &bs
);
988 if (is
.s
.not_found
&& bs
.s
.not_found
) {
990 if (flags
& XATTR_REPLACE
)
997 if (flags
& XATTR_CREATE
)
1000 error
= ext4_journal_get_write_access(handle
, is
.iloc
.bh
);
1004 if (!is
.s
.not_found
)
1005 error
= ext4_xattr_ibody_set(handle
, inode
, &i
, &is
);
1006 else if (!bs
.s
.not_found
)
1007 error
= ext4_xattr_block_set(handle
, inode
, &i
, &bs
);
1009 error
= ext4_xattr_ibody_set(handle
, inode
, &i
, &is
);
1010 if (!error
&& !bs
.s
.not_found
) {
1012 error
= ext4_xattr_block_set(handle
, inode
, &i
, &bs
);
1013 } else if (error
== -ENOSPC
) {
1014 error
= ext4_xattr_block_set(handle
, inode
, &i
, &bs
);
1017 if (!is
.s
.not_found
) {
1019 error
= ext4_xattr_ibody_set(handle
, inode
, &i
,
1025 ext4_xattr_update_super_block(handle
, inode
->i_sb
);
1026 inode
->i_ctime
= ext4_current_time(inode
);
1028 EXT4_I(inode
)->i_state
&= ~EXT4_STATE_NO_EXPAND
;
1029 error
= ext4_mark_iloc_dirty(handle
, inode
, &is
.iloc
);
1031 * The bh is consumed by ext4_mark_iloc_dirty, even with
1042 up_write(&EXT4_I(inode
)->xattr_sem
);
1049 * Like ext4_xattr_set_handle, but start from an inode. This extended
1050 * attribute modification is a filesystem transaction by itself.
1052 * Returns 0, or a negative error number on failure.
1055 ext4_xattr_set(struct inode
*inode
, int name_index
, const char *name
,
1056 const void *value
, size_t value_len
, int flags
)
1059 int error
, retries
= 0;
1062 handle
= ext4_journal_start(inode
, EXT4_DATA_TRANS_BLOCKS(inode
->i_sb
));
1063 if (IS_ERR(handle
)) {
1064 error
= PTR_ERR(handle
);
1068 error
= ext4_xattr_set_handle(handle
, inode
, name_index
, name
,
1069 value
, value_len
, flags
);
1070 error2
= ext4_journal_stop(handle
);
1071 if (error
== -ENOSPC
&&
1072 ext4_should_retry_alloc(inode
->i_sb
, &retries
))
1082 * Shift the EA entries in the inode to create space for the increased
1085 static void ext4_xattr_shift_entries(struct ext4_xattr_entry
*entry
,
1086 int value_offs_shift
, void *to
,
1087 void *from
, size_t n
, int blocksize
)
1089 struct ext4_xattr_entry
*last
= entry
;
1092 /* Adjust the value offsets of the entries */
1093 for (; !IS_LAST_ENTRY(last
); last
= EXT4_XATTR_NEXT(last
)) {
1094 if (!last
->e_value_block
&& last
->e_value_size
) {
1095 new_offs
= le16_to_cpu(last
->e_value_offs
) +
1097 BUG_ON(new_offs
+ le32_to_cpu(last
->e_value_size
)
1099 last
->e_value_offs
= cpu_to_le16(new_offs
);
1102 /* Shift the entries by n bytes */
1103 memmove(to
, from
, n
);
1107 * Expand an inode by new_extra_isize bytes when EAs are present.
1108 * Returns 0 on success or negative error number on failure.
1110 int ext4_expand_extra_isize_ea(struct inode
*inode
, int new_extra_isize
,
1111 struct ext4_inode
*raw_inode
, handle_t
*handle
)
1113 struct ext4_xattr_ibody_header
*header
;
1114 struct ext4_xattr_entry
*entry
, *last
, *first
;
1115 struct buffer_head
*bh
= NULL
;
1116 struct ext4_xattr_ibody_find
*is
= NULL
;
1117 struct ext4_xattr_block_find
*bs
= NULL
;
1118 char *buffer
= NULL
, *b_entry_name
= NULL
;
1119 size_t min_offs
, free
;
1120 int total_ino
, total_blk
;
1121 void *base
, *start
, *end
;
1122 int extra_isize
= 0, error
= 0, tried_min_extra_isize
= 0;
1123 int s_min_extra_isize
= EXT4_SB(inode
->i_sb
)->s_es
->s_min_extra_isize
;
1125 down_write(&EXT4_I(inode
)->xattr_sem
);
1127 if (EXT4_I(inode
)->i_extra_isize
>= new_extra_isize
) {
1128 up_write(&EXT4_I(inode
)->xattr_sem
);
1132 header
= IHDR(inode
, raw_inode
);
1133 entry
= IFIRST(header
);
1136 * Check if enough free space is available in the inode to shift the
1137 * entries ahead by new_extra_isize.
1140 base
= start
= entry
;
1141 end
= (void *)raw_inode
+ EXT4_SB(inode
->i_sb
)->s_inode_size
;
1142 min_offs
= end
- base
;
1144 total_ino
= sizeof(struct ext4_xattr_ibody_header
);
1146 free
= ext4_xattr_free_space(last
, &min_offs
, base
, &total_ino
);
1147 if (free
>= new_extra_isize
) {
1148 entry
= IFIRST(header
);
1149 ext4_xattr_shift_entries(entry
, EXT4_I(inode
)->i_extra_isize
1150 - new_extra_isize
, (void *)raw_inode
+
1151 EXT4_GOOD_OLD_INODE_SIZE
+ new_extra_isize
,
1152 (void *)header
, total_ino
,
1153 inode
->i_sb
->s_blocksize
);
1154 EXT4_I(inode
)->i_extra_isize
= new_extra_isize
;
1160 * Enough free space isn't available in the inode, check if
1161 * EA block can hold new_extra_isize bytes.
1163 if (EXT4_I(inode
)->i_file_acl
) {
1164 bh
= sb_bread(inode
->i_sb
, EXT4_I(inode
)->i_file_acl
);
1168 if (ext4_xattr_check_block(bh
)) {
1169 ext4_error(inode
->i_sb
, __FUNCTION__
,
1170 "inode %lu: bad block %llu", inode
->i_ino
,
1171 EXT4_I(inode
)->i_file_acl
);
1177 end
= bh
->b_data
+ bh
->b_size
;
1178 min_offs
= end
- base
;
1179 free
= ext4_xattr_free_space(first
, &min_offs
, base
,
1181 if (free
< new_extra_isize
) {
1182 if (!tried_min_extra_isize
&& s_min_extra_isize
) {
1183 tried_min_extra_isize
++;
1184 new_extra_isize
= s_min_extra_isize
;
1192 free
= inode
->i_sb
->s_blocksize
;
1195 while (new_extra_isize
> 0) {
1196 size_t offs
, size
, entry_size
;
1197 struct ext4_xattr_entry
*small_entry
= NULL
;
1198 struct ext4_xattr_info i
= {
1202 unsigned int total_size
; /* EA entry size + value size */
1203 unsigned int shift_bytes
; /* No. of bytes to shift EAs by? */
1204 unsigned int min_total_size
= ~0U;
1206 is
= kzalloc(sizeof(struct ext4_xattr_ibody_find
), GFP_NOFS
);
1207 bs
= kzalloc(sizeof(struct ext4_xattr_block_find
), GFP_NOFS
);
1213 is
->s
.not_found
= -ENODATA
;
1214 bs
->s
.not_found
= -ENODATA
;
1218 last
= IFIRST(header
);
1219 /* Find the entry best suited to be pushed into EA block */
1221 for (; !IS_LAST_ENTRY(last
); last
= EXT4_XATTR_NEXT(last
)) {
1223 EXT4_XATTR_SIZE(le32_to_cpu(last
->e_value_size
)) +
1224 EXT4_XATTR_LEN(last
->e_name_len
);
1225 if (total_size
<= free
&& total_size
< min_total_size
) {
1226 if (total_size
< new_extra_isize
) {
1230 min_total_size
= total_size
;
1235 if (entry
== NULL
) {
1237 entry
= small_entry
;
1239 if (!tried_min_extra_isize
&&
1240 s_min_extra_isize
) {
1241 tried_min_extra_isize
++;
1242 new_extra_isize
= s_min_extra_isize
;
1249 offs
= le16_to_cpu(entry
->e_value_offs
);
1250 size
= le32_to_cpu(entry
->e_value_size
);
1251 entry_size
= EXT4_XATTR_LEN(entry
->e_name_len
);
1252 i
.name_index
= entry
->e_name_index
,
1253 buffer
= kmalloc(EXT4_XATTR_SIZE(size
), GFP_NOFS
);
1254 b_entry_name
= kmalloc(entry
->e_name_len
+ 1, GFP_NOFS
);
1255 if (!buffer
|| !b_entry_name
) {
1259 /* Save the entry name and the entry value */
1260 memcpy(buffer
, (void *)IFIRST(header
) + offs
,
1261 EXT4_XATTR_SIZE(size
));
1262 memcpy(b_entry_name
, entry
->e_name
, entry
->e_name_len
);
1263 b_entry_name
[entry
->e_name_len
] = '\0';
1264 i
.name
= b_entry_name
;
1266 error
= ext4_get_inode_loc(inode
, &is
->iloc
);
1270 error
= ext4_xattr_ibody_find(inode
, &i
, is
);
1274 /* Remove the chosen entry from the inode */
1275 error
= ext4_xattr_ibody_set(handle
, inode
, &i
, is
);
1277 entry
= IFIRST(header
);
1278 if (entry_size
+ EXT4_XATTR_SIZE(size
) >= new_extra_isize
)
1279 shift_bytes
= new_extra_isize
;
1281 shift_bytes
= entry_size
+ size
;
1282 /* Adjust the offsets and shift the remaining entries ahead */
1283 ext4_xattr_shift_entries(entry
, EXT4_I(inode
)->i_extra_isize
-
1284 shift_bytes
, (void *)raw_inode
+
1285 EXT4_GOOD_OLD_INODE_SIZE
+ extra_isize
+ shift_bytes
,
1286 (void *)header
, total_ino
- entry_size
,
1287 inode
->i_sb
->s_blocksize
);
1289 extra_isize
+= shift_bytes
;
1290 new_extra_isize
-= shift_bytes
;
1291 EXT4_I(inode
)->i_extra_isize
= extra_isize
;
1293 i
.name
= b_entry_name
;
1295 i
.value_len
= cpu_to_le32(size
);
1296 error
= ext4_xattr_block_find(inode
, &i
, bs
);
1300 /* Add entry which was removed from the inode into the block */
1301 error
= ext4_xattr_block_set(handle
, inode
, &i
, bs
);
1304 kfree(b_entry_name
);
1306 brelse(is
->iloc
.bh
);
1311 up_write(&EXT4_I(inode
)->xattr_sem
);
1315 kfree(b_entry_name
);
1318 brelse(is
->iloc
.bh
);
1322 up_write(&EXT4_I(inode
)->xattr_sem
);
1329 * ext4_xattr_delete_inode()
1331 * Free extended attribute resources associated with this inode. This
1332 * is called immediately before an inode is freed. We have exclusive
1333 * access to the inode.
1336 ext4_xattr_delete_inode(handle_t
*handle
, struct inode
*inode
)
1338 struct buffer_head
*bh
= NULL
;
1340 if (!EXT4_I(inode
)->i_file_acl
)
1342 bh
= sb_bread(inode
->i_sb
, EXT4_I(inode
)->i_file_acl
);
1344 ext4_error(inode
->i_sb
, __FUNCTION__
,
1345 "inode %lu: block %llu read error", inode
->i_ino
,
1346 EXT4_I(inode
)->i_file_acl
);
1349 if (BHDR(bh
)->h_magic
!= cpu_to_le32(EXT4_XATTR_MAGIC
) ||
1350 BHDR(bh
)->h_blocks
!= cpu_to_le32(1)) {
1351 ext4_error(inode
->i_sb
, __FUNCTION__
,
1352 "inode %lu: bad block %llu", inode
->i_ino
,
1353 EXT4_I(inode
)->i_file_acl
);
1356 ext4_xattr_release_block(handle
, inode
, bh
);
1357 EXT4_I(inode
)->i_file_acl
= 0;
1364 * ext4_xattr_put_super()
1366 * This is called when a file system is unmounted.
1369 ext4_xattr_put_super(struct super_block
*sb
)
1371 mb_cache_shrink(sb
->s_bdev
);
1375 * ext4_xattr_cache_insert()
1377 * Create a new entry in the extended attribute cache, and insert
1378 * it unless such an entry is already in the cache.
1380 * Returns 0, or a negative error number on failure.
1383 ext4_xattr_cache_insert(struct buffer_head
*bh
)
1385 __u32 hash
= le32_to_cpu(BHDR(bh
)->h_hash
);
1386 struct mb_cache_entry
*ce
;
1389 ce
= mb_cache_entry_alloc(ext4_xattr_cache
);
1391 ea_bdebug(bh
, "out of memory");
1394 error
= mb_cache_entry_insert(ce
, bh
->b_bdev
, bh
->b_blocknr
, &hash
);
1396 mb_cache_entry_free(ce
);
1397 if (error
== -EBUSY
) {
1398 ea_bdebug(bh
, "already in cache");
1402 ea_bdebug(bh
, "inserting [%x]", (int)hash
);
1403 mb_cache_entry_release(ce
);
1410 * Compare two extended attribute blocks for equality.
1412 * Returns 0 if the blocks are equal, 1 if they differ, and
1413 * a negative error number on errors.
1416 ext4_xattr_cmp(struct ext4_xattr_header
*header1
,
1417 struct ext4_xattr_header
*header2
)
1419 struct ext4_xattr_entry
*entry1
, *entry2
;
1421 entry1
= ENTRY(header1
+1);
1422 entry2
= ENTRY(header2
+1);
1423 while (!IS_LAST_ENTRY(entry1
)) {
1424 if (IS_LAST_ENTRY(entry2
))
1426 if (entry1
->e_hash
!= entry2
->e_hash
||
1427 entry1
->e_name_index
!= entry2
->e_name_index
||
1428 entry1
->e_name_len
!= entry2
->e_name_len
||
1429 entry1
->e_value_size
!= entry2
->e_value_size
||
1430 memcmp(entry1
->e_name
, entry2
->e_name
, entry1
->e_name_len
))
1432 if (entry1
->e_value_block
!= 0 || entry2
->e_value_block
!= 0)
1434 if (memcmp((char *)header1
+ le16_to_cpu(entry1
->e_value_offs
),
1435 (char *)header2
+ le16_to_cpu(entry2
->e_value_offs
),
1436 le32_to_cpu(entry1
->e_value_size
)))
1439 entry1
= EXT4_XATTR_NEXT(entry1
);
1440 entry2
= EXT4_XATTR_NEXT(entry2
);
1442 if (!IS_LAST_ENTRY(entry2
))
1448 * ext4_xattr_cache_find()
1450 * Find an identical extended attribute block.
1452 * Returns a pointer to the block found, or NULL if such a block was
1453 * not found or an error occurred.
1455 static struct buffer_head
*
1456 ext4_xattr_cache_find(struct inode
*inode
, struct ext4_xattr_header
*header
,
1457 struct mb_cache_entry
**pce
)
1459 __u32 hash
= le32_to_cpu(header
->h_hash
);
1460 struct mb_cache_entry
*ce
;
1462 if (!header
->h_hash
)
1463 return NULL
; /* never share */
1464 ea_idebug(inode
, "looking for cached blocks [%x]", (int)hash
);
1466 ce
= mb_cache_entry_find_first(ext4_xattr_cache
, 0,
1467 inode
->i_sb
->s_bdev
, hash
);
1469 struct buffer_head
*bh
;
1472 if (PTR_ERR(ce
) == -EAGAIN
)
1476 bh
= sb_bread(inode
->i_sb
, ce
->e_block
);
1478 ext4_error(inode
->i_sb
, __FUNCTION__
,
1479 "inode %lu: block %lu read error",
1480 inode
->i_ino
, (unsigned long) ce
->e_block
);
1481 } else if (le32_to_cpu(BHDR(bh
)->h_refcount
) >=
1482 EXT4_XATTR_REFCOUNT_MAX
) {
1483 ea_idebug(inode
, "block %lu refcount %d>=%d",
1484 (unsigned long) ce
->e_block
,
1485 le32_to_cpu(BHDR(bh
)->h_refcount
),
1486 EXT4_XATTR_REFCOUNT_MAX
);
1487 } else if (ext4_xattr_cmp(header
, BHDR(bh
)) == 0) {
1492 ce
= mb_cache_entry_find_next(ce
, 0, inode
->i_sb
->s_bdev
, hash
);
1497 #define NAME_HASH_SHIFT 5
1498 #define VALUE_HASH_SHIFT 16
1501 * ext4_xattr_hash_entry()
1503 * Compute the hash of an extended attribute.
1505 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header
*header
,
1506 struct ext4_xattr_entry
*entry
)
1509 char *name
= entry
->e_name
;
1512 for (n
=0; n
< entry
->e_name_len
; n
++) {
1513 hash
= (hash
<< NAME_HASH_SHIFT
) ^
1514 (hash
>> (8*sizeof(hash
) - NAME_HASH_SHIFT
)) ^
1518 if (entry
->e_value_block
== 0 && entry
->e_value_size
!= 0) {
1519 __le32
*value
= (__le32
*)((char *)header
+
1520 le16_to_cpu(entry
->e_value_offs
));
1521 for (n
= (le32_to_cpu(entry
->e_value_size
) +
1522 EXT4_XATTR_ROUND
) >> EXT4_XATTR_PAD_BITS
; n
; n
--) {
1523 hash
= (hash
<< VALUE_HASH_SHIFT
) ^
1524 (hash
>> (8*sizeof(hash
) - VALUE_HASH_SHIFT
)) ^
1525 le32_to_cpu(*value
++);
1528 entry
->e_hash
= cpu_to_le32(hash
);
1531 #undef NAME_HASH_SHIFT
1532 #undef VALUE_HASH_SHIFT
1534 #define BLOCK_HASH_SHIFT 16
1537 * ext4_xattr_rehash()
1539 * Re-compute the extended attribute hash value after an entry has changed.
1541 static void ext4_xattr_rehash(struct ext4_xattr_header
*header
,
1542 struct ext4_xattr_entry
*entry
)
1544 struct ext4_xattr_entry
*here
;
1547 ext4_xattr_hash_entry(header
, entry
);
1548 here
= ENTRY(header
+1);
1549 while (!IS_LAST_ENTRY(here
)) {
1550 if (!here
->e_hash
) {
1551 /* Block is not shared if an entry's hash value == 0 */
1555 hash
= (hash
<< BLOCK_HASH_SHIFT
) ^
1556 (hash
>> (8*sizeof(hash
) - BLOCK_HASH_SHIFT
)) ^
1557 le32_to_cpu(here
->e_hash
);
1558 here
= EXT4_XATTR_NEXT(here
);
1560 header
->h_hash
= cpu_to_le32(hash
);
1563 #undef BLOCK_HASH_SHIFT
1566 init_ext4_xattr(void)
1568 ext4_xattr_cache
= mb_cache_create("ext4_xattr", NULL
,
1569 sizeof(struct mb_cache_entry
) +
1570 sizeof(((struct mb_cache_entry
*) 0)->e_indexes
[0]), 1, 6);
1571 if (!ext4_xattr_cache
)
1577 exit_ext4_xattr(void)
1579 if (ext4_xattr_cache
)
1580 mb_cache_destroy(ext4_xattr_cache
);
1581 ext4_xattr_cache
= NULL
;