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;
902 block = ext4_new_meta_blocks(handle, inode, goal, 0,
907 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
908 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
910 ea_idebug(inode, "creating block %llu",
911 (unsigned long long)block);
913 new_bh = sb_getblk(sb, block);
914 if (unlikely(!new_bh)) {
917 ext4_free_blocks(handle, inode, NULL, block, 1,
918 EXT4_FREE_BLOCKS_METADATA);
922 error = ext4_journal_get_create_access(handle, new_bh);
924 unlock_buffer(new_bh);
928 memcpy(new_bh->b_data, s->base, new_bh->b_size);
929 set_buffer_uptodate(new_bh);
930 unlock_buffer(new_bh);
931 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
932 error = ext4_handle_dirty_xattr_block(handle,
939 /* Update the inode. */
940 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
942 /* Drop the previous xattr block. */
943 if (bs->bh && bs->bh != new_bh)
944 ext4_xattr_release_block(handle, inode, bs->bh);
949 mb_cache_entry_release(ce);
951 if (!(bs->bh && s->base == bs->bh->b_data))
957 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
961 EXT4_ERROR_INODE(inode, "bad block %llu",
962 EXT4_I(inode)->i_file_acl);
968 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
969 struct ext4_xattr_ibody_find *is)
971 struct ext4_xattr_ibody_header *header;
972 struct ext4_inode *raw_inode;
975 if (EXT4_I(inode)->i_extra_isize == 0)
977 raw_inode = ext4_raw_inode(&is->iloc);
978 header = IHDR(inode, raw_inode);
979 is->s.base = is->s.first = IFIRST(header);
980 is->s.here = is->s.first;
981 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
982 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
983 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
986 /* Find the named attribute. */
987 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
989 (void *)is->s.base, 0);
990 if (error && error != -ENODATA)
992 is->s.not_found = error;
997 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
998 struct ext4_xattr_info *i,
999 struct ext4_xattr_ibody_find *is)
1001 struct ext4_xattr_ibody_header *header;
1002 struct ext4_xattr_search *s = &is->s;
1005 if (EXT4_I(inode)->i_extra_isize == 0)
1007 error = ext4_xattr_set_entry(i, s);
1009 if (error == -ENOSPC &&
1010 ext4_has_inline_data(inode)) {
1011 error = ext4_try_to_evict_inline_data(handle, inode,
1012 EXT4_XATTR_LEN(strlen(i->name) +
1013 EXT4_XATTR_SIZE(i->value_len)));
1016 error = ext4_xattr_ibody_find(inode, i, is);
1019 error = ext4_xattr_set_entry(i, s);
1024 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1025 if (!IS_LAST_ENTRY(s->first)) {
1026 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1027 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1029 header->h_magic = cpu_to_le32(0);
1030 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1035 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1036 struct ext4_xattr_info *i,
1037 struct ext4_xattr_ibody_find *is)
1039 struct ext4_xattr_ibody_header *header;
1040 struct ext4_xattr_search *s = &is->s;
1043 if (EXT4_I(inode)->i_extra_isize == 0)
1045 error = ext4_xattr_set_entry(i, s);
1048 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1049 if (!IS_LAST_ENTRY(s->first)) {
1050 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1051 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1053 header->h_magic = cpu_to_le32(0);
1054 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1060 * ext4_xattr_set_handle()
1062 * Create, replace or remove an extended attribute for this inode. Value
1063 * is NULL to remove an existing extended attribute, and non-NULL to
1064 * either replace an existing extended attribute, or create a new extended
1065 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1066 * specify that an extended attribute must exist and must not exist
1067 * previous to the call, respectively.
1069 * Returns 0, or a negative error number on failure.
1072 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1073 const char *name, const void *value, size_t value_len,
1076 struct ext4_xattr_info i = {
1077 .name_index = name_index,
1080 .value_len = value_len,
1083 struct ext4_xattr_ibody_find is = {
1084 .s = { .not_found = -ENODATA, },
1086 struct ext4_xattr_block_find bs = {
1087 .s = { .not_found = -ENODATA, },
1089 unsigned long no_expand;
1094 if (strlen(name) > 255)
1096 down_write(&EXT4_I(inode)->xattr_sem);
1097 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1098 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1100 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1104 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1105 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1106 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1107 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1110 error = ext4_xattr_ibody_find(inode, &i, &is);
1114 error = ext4_xattr_block_find(inode, &i, &bs);
1117 if (is.s.not_found && bs.s.not_found) {
1119 if (flags & XATTR_REPLACE)
1126 if (flags & XATTR_CREATE)
1130 if (!is.s.not_found)
1131 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1132 else if (!bs.s.not_found)
1133 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1135 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1136 if (!error && !bs.s.not_found) {
1138 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1139 } else if (error == -ENOSPC) {
1140 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1141 error = ext4_xattr_block_find(inode, &i, &bs);
1145 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1148 if (!is.s.not_found) {
1150 error = ext4_xattr_ibody_set(handle, inode, &i,
1156 ext4_xattr_update_super_block(handle, inode->i_sb);
1157 inode->i_ctime = ext4_current_time(inode);
1159 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1160 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1162 * The bh is consumed by ext4_mark_iloc_dirty, even with
1167 ext4_handle_sync(handle);
1174 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1175 up_write(&EXT4_I(inode)->xattr_sem);
1182 * Like ext4_xattr_set_handle, but start from an inode. This extended
1183 * attribute modification is a filesystem transaction by itself.
1185 * Returns 0, or a negative error number on failure.
1188 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1189 const void *value, size_t value_len, int flags)
1192 int error, retries = 0;
1193 int credits = ext4_jbd2_credits_xattr(inode);
1196 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1197 if (IS_ERR(handle)) {
1198 error = PTR_ERR(handle);
1202 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1203 value, value_len, flags);
1204 error2 = ext4_journal_stop(handle);
1205 if (error == -ENOSPC &&
1206 ext4_should_retry_alloc(inode->i_sb, &retries))
1216 * Shift the EA entries in the inode to create space for the increased
1219 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1220 int value_offs_shift, void *to,
1221 void *from, size_t n, int blocksize)
1223 struct ext4_xattr_entry *last = entry;
1226 /* Adjust the value offsets of the entries */
1227 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1228 if (!last->e_value_block && last->e_value_size) {
1229 new_offs = le16_to_cpu(last->e_value_offs) +
1231 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1233 last->e_value_offs = cpu_to_le16(new_offs);
1236 /* Shift the entries by n bytes */
1237 memmove(to, from, n);
1241 * Expand an inode by new_extra_isize bytes when EAs are present.
1242 * Returns 0 on success or negative error number on failure.
1244 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1245 struct ext4_inode *raw_inode, handle_t *handle)
1247 struct ext4_xattr_ibody_header *header;
1248 struct ext4_xattr_entry *entry, *last, *first;
1249 struct buffer_head *bh = NULL;
1250 struct ext4_xattr_ibody_find *is = NULL;
1251 struct ext4_xattr_block_find *bs = NULL;
1252 char *buffer = NULL, *b_entry_name = NULL;
1253 size_t min_offs, free;
1255 void *base, *start, *end;
1256 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1257 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1259 down_write(&EXT4_I(inode)->xattr_sem);
1261 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1262 up_write(&EXT4_I(inode)->xattr_sem);
1266 header = IHDR(inode, raw_inode);
1267 entry = IFIRST(header);
1270 * Check if enough free space is available in the inode to shift the
1271 * entries ahead by new_extra_isize.
1274 base = start = entry;
1275 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1276 min_offs = end - base;
1278 total_ino = sizeof(struct ext4_xattr_ibody_header);
1280 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1281 if (free >= new_extra_isize) {
1282 entry = IFIRST(header);
1283 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1284 - new_extra_isize, (void *)raw_inode +
1285 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1286 (void *)header, total_ino,
1287 inode->i_sb->s_blocksize);
1288 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1294 * Enough free space isn't available in the inode, check if
1295 * EA block can hold new_extra_isize bytes.
1297 if (EXT4_I(inode)->i_file_acl) {
1298 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1302 if (ext4_xattr_check_block(inode, bh)) {
1303 EXT4_ERROR_INODE(inode, "bad block %llu",
1304 EXT4_I(inode)->i_file_acl);
1310 end = bh->b_data + bh->b_size;
1311 min_offs = end - base;
1312 free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1313 if (free < new_extra_isize) {
1314 if (!tried_min_extra_isize && s_min_extra_isize) {
1315 tried_min_extra_isize++;
1316 new_extra_isize = s_min_extra_isize;
1324 free = inode->i_sb->s_blocksize;
1327 while (new_extra_isize > 0) {
1328 size_t offs, size, entry_size;
1329 struct ext4_xattr_entry *small_entry = NULL;
1330 struct ext4_xattr_info i = {
1334 unsigned int total_size; /* EA entry size + value size */
1335 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1336 unsigned int min_total_size = ~0U;
1338 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1339 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1345 is->s.not_found = -ENODATA;
1346 bs->s.not_found = -ENODATA;
1350 last = IFIRST(header);
1351 /* Find the entry best suited to be pushed into EA block */
1353 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1355 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1356 EXT4_XATTR_LEN(last->e_name_len);
1357 if (total_size <= free && total_size < min_total_size) {
1358 if (total_size < new_extra_isize) {
1362 min_total_size = total_size;
1367 if (entry == NULL) {
1369 entry = small_entry;
1371 if (!tried_min_extra_isize &&
1372 s_min_extra_isize) {
1373 tried_min_extra_isize++;
1374 new_extra_isize = s_min_extra_isize;
1375 kfree(is); is = NULL;
1376 kfree(bs); bs = NULL;
1384 offs = le16_to_cpu(entry->e_value_offs);
1385 size = le32_to_cpu(entry->e_value_size);
1386 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1387 i.name_index = entry->e_name_index,
1388 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1389 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1390 if (!buffer || !b_entry_name) {
1394 /* Save the entry name and the entry value */
1395 memcpy(buffer, (void *)IFIRST(header) + offs,
1396 EXT4_XATTR_SIZE(size));
1397 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1398 b_entry_name[entry->e_name_len] = '\0';
1399 i.name = b_entry_name;
1401 error = ext4_get_inode_loc(inode, &is->iloc);
1405 error = ext4_xattr_ibody_find(inode, &i, is);
1409 /* Remove the chosen entry from the inode */
1410 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1414 entry = IFIRST(header);
1415 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1416 shift_bytes = new_extra_isize;
1418 shift_bytes = entry_size + size;
1419 /* Adjust the offsets and shift the remaining entries ahead */
1420 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1421 shift_bytes, (void *)raw_inode +
1422 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1423 (void *)header, total_ino - entry_size,
1424 inode->i_sb->s_blocksize);
1426 extra_isize += shift_bytes;
1427 new_extra_isize -= shift_bytes;
1428 EXT4_I(inode)->i_extra_isize = extra_isize;
1430 i.name = b_entry_name;
1433 error = ext4_xattr_block_find(inode, &i, bs);
1437 /* Add entry which was removed from the inode into the block */
1438 error = ext4_xattr_block_set(handle, inode, &i, bs);
1441 kfree(b_entry_name);
1443 b_entry_name = NULL;
1445 brelse(is->iloc.bh);
1450 up_write(&EXT4_I(inode)->xattr_sem);
1454 kfree(b_entry_name);
1457 brelse(is->iloc.bh);
1461 up_write(&EXT4_I(inode)->xattr_sem);
1468 * ext4_xattr_delete_inode()
1470 * Free extended attribute resources associated with this inode. This
1471 * is called immediately before an inode is freed. We have exclusive
1472 * access to the inode.
1475 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1477 struct buffer_head *bh = NULL;
1479 if (!EXT4_I(inode)->i_file_acl)
1481 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1483 EXT4_ERROR_INODE(inode, "block %llu read error",
1484 EXT4_I(inode)->i_file_acl);
1487 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1488 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1489 EXT4_ERROR_INODE(inode, "bad block %llu",
1490 EXT4_I(inode)->i_file_acl);
1493 ext4_xattr_release_block(handle, inode, bh);
1494 EXT4_I(inode)->i_file_acl = 0;
1501 * ext4_xattr_put_super()
1503 * This is called when a file system is unmounted.
1506 ext4_xattr_put_super(struct super_block *sb)
1508 mb_cache_shrink(sb->s_bdev);
1512 * ext4_xattr_cache_insert()
1514 * Create a new entry in the extended attribute cache, and insert
1515 * it unless such an entry is already in the cache.
1517 * Returns 0, or a negative error number on failure.
1520 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1522 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1523 struct mb_cache_entry *ce;
1526 ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS);
1528 ea_bdebug(bh, "out of memory");
1531 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1533 mb_cache_entry_free(ce);
1534 if (error == -EBUSY) {
1535 ea_bdebug(bh, "already in cache");
1539 ea_bdebug(bh, "inserting [%x]", (int)hash);
1540 mb_cache_entry_release(ce);
1547 * Compare two extended attribute blocks for equality.
1549 * Returns 0 if the blocks are equal, 1 if they differ, and
1550 * a negative error number on errors.
1553 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1554 struct ext4_xattr_header *header2)
1556 struct ext4_xattr_entry *entry1, *entry2;
1558 entry1 = ENTRY(header1+1);
1559 entry2 = ENTRY(header2+1);
1560 while (!IS_LAST_ENTRY(entry1)) {
1561 if (IS_LAST_ENTRY(entry2))
1563 if (entry1->e_hash != entry2->e_hash ||
1564 entry1->e_name_index != entry2->e_name_index ||
1565 entry1->e_name_len != entry2->e_name_len ||
1566 entry1->e_value_size != entry2->e_value_size ||
1567 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1569 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1571 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1572 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1573 le32_to_cpu(entry1->e_value_size)))
1576 entry1 = EXT4_XATTR_NEXT(entry1);
1577 entry2 = EXT4_XATTR_NEXT(entry2);
1579 if (!IS_LAST_ENTRY(entry2))
1585 * ext4_xattr_cache_find()
1587 * Find an identical extended attribute block.
1589 * Returns a pointer to the block found, or NULL if such a block was
1590 * not found or an error occurred.
1592 static struct buffer_head *
1593 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1594 struct mb_cache_entry **pce)
1596 __u32 hash = le32_to_cpu(header->h_hash);
1597 struct mb_cache_entry *ce;
1598 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1600 if (!header->h_hash)
1601 return NULL; /* never share */
1602 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1604 ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev,
1607 struct buffer_head *bh;
1610 if (PTR_ERR(ce) == -EAGAIN)
1614 bh = sb_bread(inode->i_sb, ce->e_block);
1616 EXT4_ERROR_INODE(inode, "block %lu read error",
1617 (unsigned long) ce->e_block);
1618 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1619 EXT4_XATTR_REFCOUNT_MAX) {
1620 ea_idebug(inode, "block %lu refcount %d>=%d",
1621 (unsigned long) ce->e_block,
1622 le32_to_cpu(BHDR(bh)->h_refcount),
1623 EXT4_XATTR_REFCOUNT_MAX);
1624 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1629 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1634 #define NAME_HASH_SHIFT 5
1635 #define VALUE_HASH_SHIFT 16
1638 * ext4_xattr_hash_entry()
1640 * Compute the hash of an extended attribute.
1642 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1643 struct ext4_xattr_entry *entry)
1646 char *name = entry->e_name;
1649 for (n = 0; n < entry->e_name_len; n++) {
1650 hash = (hash << NAME_HASH_SHIFT) ^
1651 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1655 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1656 __le32 *value = (__le32 *)((char *)header +
1657 le16_to_cpu(entry->e_value_offs));
1658 for (n = (le32_to_cpu(entry->e_value_size) +
1659 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1660 hash = (hash << VALUE_HASH_SHIFT) ^
1661 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1662 le32_to_cpu(*value++);
1665 entry->e_hash = cpu_to_le32(hash);
1668 #undef NAME_HASH_SHIFT
1669 #undef VALUE_HASH_SHIFT
1671 #define BLOCK_HASH_SHIFT 16
1674 * ext4_xattr_rehash()
1676 * Re-compute the extended attribute hash value after an entry has changed.
1678 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1679 struct ext4_xattr_entry *entry)
1681 struct ext4_xattr_entry *here;
1684 ext4_xattr_hash_entry(header, entry);
1685 here = ENTRY(header+1);
1686 while (!IS_LAST_ENTRY(here)) {
1687 if (!here->e_hash) {
1688 /* Block is not shared if an entry's hash value == 0 */
1692 hash = (hash << BLOCK_HASH_SHIFT) ^
1693 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1694 le32_to_cpu(here->e_hash);
1695 here = EXT4_XATTR_NEXT(here);
1697 header->h_hash = cpu_to_le32(hash);
1700 #undef BLOCK_HASH_SHIFT
1702 #define HASH_BUCKET_BITS 10
1705 ext4_xattr_create_cache(char *name)
1707 return mb_cache_create(name, HASH_BUCKET_BITS);
1710 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1713 mb_cache_destroy(cache);