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 down_read(&EXT4_I(inode)->xattr_sem);
373 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
375 if (error == -ENODATA)
376 error = ext4_xattr_block_get(inode, name_index, name, buffer,
378 up_read(&EXT4_I(inode)->xattr_sem);
383 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
384 char *buffer, size_t buffer_size)
386 size_t rest = buffer_size;
388 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
389 const struct xattr_handler *handler =
390 ext4_xattr_handler(entry->e_name_index);
393 size_t size = handler->list(dentry, buffer, rest,
405 return buffer_size - rest;
409 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
411 struct inode *inode = dentry->d_inode;
412 struct buffer_head *bh = NULL;
414 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
416 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
417 buffer, (long)buffer_size);
420 if (!EXT4_I(inode)->i_file_acl)
422 ea_idebug(inode, "reading block %llu",
423 (unsigned long long)EXT4_I(inode)->i_file_acl);
424 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
428 ea_bdebug(bh, "b_count=%d, refcount=%d",
429 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
430 if (ext4_xattr_check_block(inode, bh)) {
431 EXT4_ERROR_INODE(inode, "bad block %llu",
432 EXT4_I(inode)->i_file_acl);
436 ext4_xattr_cache_insert(ext4_mb_cache, bh);
437 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
446 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
448 struct inode *inode = dentry->d_inode;
449 struct ext4_xattr_ibody_header *header;
450 struct ext4_inode *raw_inode;
451 struct ext4_iloc iloc;
455 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
457 error = ext4_get_inode_loc(inode, &iloc);
460 raw_inode = ext4_raw_inode(&iloc);
461 header = IHDR(inode, raw_inode);
462 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
463 error = ext4_xattr_check_names(IFIRST(header), end);
466 error = ext4_xattr_list_entries(dentry, IFIRST(header),
467 buffer, buffer_size);
477 * Copy a list of attribute names into the buffer
478 * provided, or compute the buffer size required.
479 * Buffer is NULL to compute the size of the buffer required.
481 * Returns a negative error number on failure, or the number of bytes
482 * used / required on success.
485 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
489 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
490 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
497 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
502 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
507 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
510 static void ext4_xattr_update_super_block(handle_t *handle,
511 struct super_block *sb)
513 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
516 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
517 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
518 ext4_handle_dirty_super(handle, sb);
523 * Release the xattr block BH: If the reference count is > 1, decrement
524 * it; otherwise free the block.
527 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
528 struct buffer_head *bh)
530 struct mb_cache_entry *ce = NULL;
532 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
534 ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr);
535 error = ext4_journal_get_write_access(handle, bh);
540 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
541 ea_bdebug(bh, "refcount now=0; freeing");
543 mb_cache_entry_free(ce);
545 ext4_free_blocks(handle, inode, bh, 0, 1,
546 EXT4_FREE_BLOCKS_METADATA |
547 EXT4_FREE_BLOCKS_FORGET);
550 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
552 mb_cache_entry_release(ce);
554 error = ext4_handle_dirty_xattr_block(handle, inode, bh);
556 ext4_handle_sync(handle);
557 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
558 ea_bdebug(bh, "refcount now=%d; releasing",
559 le32_to_cpu(BHDR(bh)->h_refcount));
562 ext4_std_error(inode->i_sb, error);
567 * Find the available free space for EAs. This also returns the total number of
568 * bytes used by EA entries.
570 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
571 size_t *min_offs, void *base, int *total)
573 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
574 if (!last->e_value_block && last->e_value_size) {
575 size_t offs = le16_to_cpu(last->e_value_offs);
576 if (offs < *min_offs)
580 *total += EXT4_XATTR_LEN(last->e_name_len);
582 return (*min_offs - ((void *)last - base) - sizeof(__u32));
586 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
588 struct ext4_xattr_entry *last;
589 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
591 /* Compute min_offs and last. */
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);
600 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
602 if (!s->here->e_value_block && s->here->e_value_size) {
603 size_t size = le32_to_cpu(s->here->e_value_size);
604 free += EXT4_XATTR_SIZE(size);
606 free += EXT4_XATTR_LEN(name_len);
609 if (free < EXT4_XATTR_SIZE(i->value_len) ||
610 free < EXT4_XATTR_LEN(name_len) +
611 EXT4_XATTR_SIZE(i->value_len))
615 if (i->value && s->not_found) {
616 /* Insert the new name. */
617 size_t size = EXT4_XATTR_LEN(name_len);
618 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
619 memmove((void *)s->here + size, s->here, rest);
620 memset(s->here, 0, size);
621 s->here->e_name_index = i->name_index;
622 s->here->e_name_len = name_len;
623 memcpy(s->here->e_name, i->name, name_len);
625 if (!s->here->e_value_block && s->here->e_value_size) {
626 void *first_val = s->base + min_offs;
627 size_t offs = le16_to_cpu(s->here->e_value_offs);
628 void *val = s->base + offs;
629 size_t size = EXT4_XATTR_SIZE(
630 le32_to_cpu(s->here->e_value_size));
632 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
633 /* The old and the new value have the same
634 size. Just replace. */
635 s->here->e_value_size =
636 cpu_to_le32(i->value_len);
637 if (i->value == EXT4_ZERO_XATTR_VALUE) {
638 memset(val, 0, size);
640 /* Clear pad bytes first. */
641 memset(val + size - EXT4_XATTR_PAD, 0,
643 memcpy(val, i->value, i->value_len);
648 /* Remove the old value. */
649 memmove(first_val + size, first_val, val - first_val);
650 memset(first_val, 0, size);
651 s->here->e_value_size = 0;
652 s->here->e_value_offs = 0;
655 /* Adjust all value offsets. */
657 while (!IS_LAST_ENTRY(last)) {
658 size_t o = le16_to_cpu(last->e_value_offs);
659 if (!last->e_value_block &&
660 last->e_value_size && o < offs)
662 cpu_to_le16(o + size);
663 last = EXT4_XATTR_NEXT(last);
667 /* Remove the old name. */
668 size_t size = EXT4_XATTR_LEN(name_len);
669 last = ENTRY((void *)last - size);
670 memmove(s->here, (void *)s->here + size,
671 (void *)last - (void *)s->here + sizeof(__u32));
672 memset(last, 0, size);
677 /* Insert the new value. */
678 s->here->e_value_size = cpu_to_le32(i->value_len);
680 size_t size = EXT4_XATTR_SIZE(i->value_len);
681 void *val = s->base + min_offs - size;
682 s->here->e_value_offs = cpu_to_le16(min_offs - size);
683 if (i->value == EXT4_ZERO_XATTR_VALUE) {
684 memset(val, 0, size);
686 /* Clear the pad bytes first. */
687 memset(val + size - EXT4_XATTR_PAD, 0,
689 memcpy(val, i->value, i->value_len);
696 struct ext4_xattr_block_find {
697 struct ext4_xattr_search s;
698 struct buffer_head *bh;
702 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
703 struct ext4_xattr_block_find *bs)
705 struct super_block *sb = inode->i_sb;
708 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
709 i->name_index, i->name, i->value, (long)i->value_len);
711 if (EXT4_I(inode)->i_file_acl) {
712 /* The inode already has an extended attribute block. */
713 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
717 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
718 atomic_read(&(bs->bh->b_count)),
719 le32_to_cpu(BHDR(bs->bh)->h_refcount));
720 if (ext4_xattr_check_block(inode, bs->bh)) {
721 EXT4_ERROR_INODE(inode, "bad block %llu",
722 EXT4_I(inode)->i_file_acl);
726 /* Find the named attribute. */
727 bs->s.base = BHDR(bs->bh);
728 bs->s.first = BFIRST(bs->bh);
729 bs->s.end = bs->bh->b_data + bs->bh->b_size;
730 bs->s.here = bs->s.first;
731 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
732 i->name, bs->bh->b_size, 1);
733 if (error && error != -ENODATA)
735 bs->s.not_found = error;
744 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
745 struct ext4_xattr_info *i,
746 struct ext4_xattr_block_find *bs)
748 struct super_block *sb = inode->i_sb;
749 struct buffer_head *new_bh = NULL;
750 struct ext4_xattr_search *s = &bs->s;
751 struct mb_cache_entry *ce = NULL;
753 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
755 #define header(x) ((struct ext4_xattr_header *)(x))
757 if (i->value && i->value_len > sb->s_blocksize)
760 ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev,
762 error = ext4_journal_get_write_access(handle, bs->bh);
767 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
769 mb_cache_entry_free(ce);
772 ea_bdebug(bs->bh, "modifying in-place");
773 error = ext4_xattr_set_entry(i, s);
775 if (!IS_LAST_ENTRY(s->first))
776 ext4_xattr_rehash(header(s->base),
778 ext4_xattr_cache_insert(ext4_mb_cache,
781 unlock_buffer(bs->bh);
785 error = ext4_handle_dirty_xattr_block(handle,
792 int offset = (char *)s->here - bs->bh->b_data;
794 unlock_buffer(bs->bh);
796 mb_cache_entry_release(ce);
799 ea_bdebug(bs->bh, "cloning");
800 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
804 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
805 s->first = ENTRY(header(s->base)+1);
806 header(s->base)->h_refcount = cpu_to_le32(1);
807 s->here = ENTRY(s->base + offset);
808 s->end = s->base + bs->bh->b_size;
811 /* Allocate a buffer where we construct the new block. */
812 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
813 /* assert(header == s->base) */
817 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
818 header(s->base)->h_blocks = cpu_to_le32(1);
819 header(s->base)->h_refcount = cpu_to_le32(1);
820 s->first = ENTRY(header(s->base)+1);
821 s->here = ENTRY(header(s->base)+1);
822 s->end = s->base + sb->s_blocksize;
825 error = ext4_xattr_set_entry(i, s);
830 if (!IS_LAST_ENTRY(s->first))
831 ext4_xattr_rehash(header(s->base), s->here);
834 if (!IS_LAST_ENTRY(s->first)) {
835 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
837 /* We found an identical block in the cache. */
838 if (new_bh == bs->bh)
839 ea_bdebug(new_bh, "keeping");
841 /* The old block is released after updating
843 error = dquot_alloc_block(inode,
844 EXT4_C2B(EXT4_SB(sb), 1));
847 error = ext4_journal_get_write_access(handle,
852 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
853 ea_bdebug(new_bh, "reusing; refcount now=%d",
854 le32_to_cpu(BHDR(new_bh)->h_refcount));
855 unlock_buffer(new_bh);
856 error = ext4_handle_dirty_xattr_block(handle,
862 mb_cache_entry_release(ce);
864 } else if (bs->bh && s->base == bs->bh->b_data) {
865 /* We were modifying this block in-place. */
866 ea_bdebug(bs->bh, "keeping this block");
870 /* We need to allocate a new block */
871 ext4_fsblk_t goal, block;
873 goal = ext4_group_first_block_no(sb,
874 EXT4_I(inode)->i_block_group);
876 /* non-extent files can't have physical blocks past 2^32 */
877 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
878 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
881 * take i_data_sem because we will test
882 * i_delalloc_reserved_flag in ext4_mb_new_blocks
884 down_read((&EXT4_I(inode)->i_data_sem));
885 block = ext4_new_meta_blocks(handle, inode, goal, 0,
887 up_read((&EXT4_I(inode)->i_data_sem));
891 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
892 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
894 ea_idebug(inode, "creating block %llu",
895 (unsigned long long)block);
897 new_bh = sb_getblk(sb, block);
898 if (unlikely(!new_bh)) {
901 ext4_free_blocks(handle, inode, NULL, block, 1,
902 EXT4_FREE_BLOCKS_METADATA);
906 error = ext4_journal_get_create_access(handle, new_bh);
908 unlock_buffer(new_bh);
912 memcpy(new_bh->b_data, s->base, new_bh->b_size);
913 set_buffer_uptodate(new_bh);
914 unlock_buffer(new_bh);
915 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
916 error = ext4_handle_dirty_xattr_block(handle,
923 /* Update the inode. */
924 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
926 /* Drop the previous xattr block. */
927 if (bs->bh && bs->bh != new_bh)
928 ext4_xattr_release_block(handle, inode, bs->bh);
933 mb_cache_entry_release(ce);
935 if (!(bs->bh && s->base == bs->bh->b_data))
941 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
945 EXT4_ERROR_INODE(inode, "bad block %llu",
946 EXT4_I(inode)->i_file_acl);
952 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
953 struct ext4_xattr_ibody_find *is)
955 struct ext4_xattr_ibody_header *header;
956 struct ext4_inode *raw_inode;
959 if (EXT4_I(inode)->i_extra_isize == 0)
961 raw_inode = ext4_raw_inode(&is->iloc);
962 header = IHDR(inode, raw_inode);
963 is->s.base = is->s.first = IFIRST(header);
964 is->s.here = is->s.first;
965 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
966 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
967 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
970 /* Find the named attribute. */
971 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
973 (void *)is->s.base, 0);
974 if (error && error != -ENODATA)
976 is->s.not_found = error;
981 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
982 struct ext4_xattr_info *i,
983 struct ext4_xattr_ibody_find *is)
985 struct ext4_xattr_ibody_header *header;
986 struct ext4_xattr_search *s = &is->s;
989 if (EXT4_I(inode)->i_extra_isize == 0)
991 error = ext4_xattr_set_entry(i, s);
993 if (error == -ENOSPC &&
994 ext4_has_inline_data(inode)) {
995 error = ext4_try_to_evict_inline_data(handle, inode,
996 EXT4_XATTR_LEN(strlen(i->name) +
997 EXT4_XATTR_SIZE(i->value_len)));
1000 error = ext4_xattr_ibody_find(inode, i, is);
1003 error = ext4_xattr_set_entry(i, s);
1008 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1009 if (!IS_LAST_ENTRY(s->first)) {
1010 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1011 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1013 header->h_magic = cpu_to_le32(0);
1014 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1019 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1020 struct ext4_xattr_info *i,
1021 struct ext4_xattr_ibody_find *is)
1023 struct ext4_xattr_ibody_header *header;
1024 struct ext4_xattr_search *s = &is->s;
1027 if (EXT4_I(inode)->i_extra_isize == 0)
1029 error = ext4_xattr_set_entry(i, s);
1032 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1033 if (!IS_LAST_ENTRY(s->first)) {
1034 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1035 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1037 header->h_magic = cpu_to_le32(0);
1038 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1044 * ext4_xattr_set_handle()
1046 * Create, replace or remove an extended attribute for this inode. Value
1047 * is NULL to remove an existing extended attribute, and non-NULL to
1048 * either replace an existing extended attribute, or create a new extended
1049 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1050 * specify that an extended attribute must exist and must not exist
1051 * previous to the call, respectively.
1053 * Returns 0, or a negative error number on failure.
1056 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1057 const char *name, const void *value, size_t value_len,
1060 struct ext4_xattr_info i = {
1061 .name_index = name_index,
1064 .value_len = value_len,
1067 struct ext4_xattr_ibody_find is = {
1068 .s = { .not_found = -ENODATA, },
1070 struct ext4_xattr_block_find bs = {
1071 .s = { .not_found = -ENODATA, },
1073 unsigned long no_expand;
1078 if (strlen(name) > 255)
1080 down_write(&EXT4_I(inode)->xattr_sem);
1081 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1082 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1084 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1088 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1089 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1090 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1091 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1094 error = ext4_xattr_ibody_find(inode, &i, &is);
1098 error = ext4_xattr_block_find(inode, &i, &bs);
1101 if (is.s.not_found && bs.s.not_found) {
1103 if (flags & XATTR_REPLACE)
1110 if (flags & XATTR_CREATE)
1114 if (!is.s.not_found)
1115 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1116 else if (!bs.s.not_found)
1117 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1119 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1120 if (!error && !bs.s.not_found) {
1122 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1123 } else if (error == -ENOSPC) {
1124 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1125 error = ext4_xattr_block_find(inode, &i, &bs);
1129 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1132 if (!is.s.not_found) {
1134 error = ext4_xattr_ibody_set(handle, inode, &i,
1140 ext4_xattr_update_super_block(handle, inode->i_sb);
1141 inode->i_ctime = ext4_current_time(inode);
1143 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1144 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1146 * The bh is consumed by ext4_mark_iloc_dirty, even with
1151 ext4_handle_sync(handle);
1158 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1159 up_write(&EXT4_I(inode)->xattr_sem);
1166 * Like ext4_xattr_set_handle, but start from an inode. This extended
1167 * attribute modification is a filesystem transaction by itself.
1169 * Returns 0, or a negative error number on failure.
1172 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1173 const void *value, size_t value_len, int flags)
1176 int error, retries = 0;
1177 int credits = ext4_jbd2_credits_xattr(inode);
1180 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1181 if (IS_ERR(handle)) {
1182 error = PTR_ERR(handle);
1186 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1187 value, value_len, flags);
1188 error2 = ext4_journal_stop(handle);
1189 if (error == -ENOSPC &&
1190 ext4_should_retry_alloc(inode->i_sb, &retries))
1200 * Shift the EA entries in the inode to create space for the increased
1203 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1204 int value_offs_shift, void *to,
1205 void *from, size_t n, int blocksize)
1207 struct ext4_xattr_entry *last = entry;
1210 /* Adjust the value offsets of the entries */
1211 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1212 if (!last->e_value_block && last->e_value_size) {
1213 new_offs = le16_to_cpu(last->e_value_offs) +
1215 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1217 last->e_value_offs = cpu_to_le16(new_offs);
1220 /* Shift the entries by n bytes */
1221 memmove(to, from, n);
1225 * Expand an inode by new_extra_isize bytes when EAs are present.
1226 * Returns 0 on success or negative error number on failure.
1228 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1229 struct ext4_inode *raw_inode, handle_t *handle)
1231 struct ext4_xattr_ibody_header *header;
1232 struct ext4_xattr_entry *entry, *last, *first;
1233 struct buffer_head *bh = NULL;
1234 struct ext4_xattr_ibody_find *is = NULL;
1235 struct ext4_xattr_block_find *bs = NULL;
1236 char *buffer = NULL, *b_entry_name = NULL;
1237 size_t min_offs, free;
1239 void *base, *start, *end;
1240 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1241 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1243 down_write(&EXT4_I(inode)->xattr_sem);
1245 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1246 up_write(&EXT4_I(inode)->xattr_sem);
1250 header = IHDR(inode, raw_inode);
1251 entry = IFIRST(header);
1254 * Check if enough free space is available in the inode to shift the
1255 * entries ahead by new_extra_isize.
1258 base = start = entry;
1259 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1260 min_offs = end - base;
1262 total_ino = sizeof(struct ext4_xattr_ibody_header);
1264 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1265 if (free >= new_extra_isize) {
1266 entry = IFIRST(header);
1267 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1268 - new_extra_isize, (void *)raw_inode +
1269 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1270 (void *)header, total_ino,
1271 inode->i_sb->s_blocksize);
1272 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1278 * Enough free space isn't available in the inode, check if
1279 * EA block can hold new_extra_isize bytes.
1281 if (EXT4_I(inode)->i_file_acl) {
1282 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1286 if (ext4_xattr_check_block(inode, bh)) {
1287 EXT4_ERROR_INODE(inode, "bad block %llu",
1288 EXT4_I(inode)->i_file_acl);
1294 end = bh->b_data + bh->b_size;
1295 min_offs = end - base;
1296 free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1297 if (free < new_extra_isize) {
1298 if (!tried_min_extra_isize && s_min_extra_isize) {
1299 tried_min_extra_isize++;
1300 new_extra_isize = s_min_extra_isize;
1308 free = inode->i_sb->s_blocksize;
1311 while (new_extra_isize > 0) {
1312 size_t offs, size, entry_size;
1313 struct ext4_xattr_entry *small_entry = NULL;
1314 struct ext4_xattr_info i = {
1318 unsigned int total_size; /* EA entry size + value size */
1319 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1320 unsigned int min_total_size = ~0U;
1322 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1323 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1329 is->s.not_found = -ENODATA;
1330 bs->s.not_found = -ENODATA;
1334 last = IFIRST(header);
1335 /* Find the entry best suited to be pushed into EA block */
1337 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1339 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1340 EXT4_XATTR_LEN(last->e_name_len);
1341 if (total_size <= free && total_size < min_total_size) {
1342 if (total_size < new_extra_isize) {
1346 min_total_size = total_size;
1351 if (entry == NULL) {
1353 entry = small_entry;
1355 if (!tried_min_extra_isize &&
1356 s_min_extra_isize) {
1357 tried_min_extra_isize++;
1358 new_extra_isize = s_min_extra_isize;
1359 kfree(is); is = NULL;
1360 kfree(bs); bs = NULL;
1368 offs = le16_to_cpu(entry->e_value_offs);
1369 size = le32_to_cpu(entry->e_value_size);
1370 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1371 i.name_index = entry->e_name_index,
1372 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1373 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1374 if (!buffer || !b_entry_name) {
1378 /* Save the entry name and the entry value */
1379 memcpy(buffer, (void *)IFIRST(header) + offs,
1380 EXT4_XATTR_SIZE(size));
1381 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1382 b_entry_name[entry->e_name_len] = '\0';
1383 i.name = b_entry_name;
1385 error = ext4_get_inode_loc(inode, &is->iloc);
1389 error = ext4_xattr_ibody_find(inode, &i, is);
1393 /* Remove the chosen entry from the inode */
1394 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1398 entry = IFIRST(header);
1399 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1400 shift_bytes = new_extra_isize;
1402 shift_bytes = entry_size + size;
1403 /* Adjust the offsets and shift the remaining entries ahead */
1404 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1405 shift_bytes, (void *)raw_inode +
1406 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1407 (void *)header, total_ino - entry_size,
1408 inode->i_sb->s_blocksize);
1410 extra_isize += shift_bytes;
1411 new_extra_isize -= shift_bytes;
1412 EXT4_I(inode)->i_extra_isize = extra_isize;
1414 i.name = b_entry_name;
1417 error = ext4_xattr_block_find(inode, &i, bs);
1421 /* Add entry which was removed from the inode into the block */
1422 error = ext4_xattr_block_set(handle, inode, &i, bs);
1425 kfree(b_entry_name);
1427 b_entry_name = NULL;
1429 brelse(is->iloc.bh);
1434 up_write(&EXT4_I(inode)->xattr_sem);
1438 kfree(b_entry_name);
1441 brelse(is->iloc.bh);
1445 up_write(&EXT4_I(inode)->xattr_sem);
1452 * ext4_xattr_delete_inode()
1454 * Free extended attribute resources associated with this inode. This
1455 * is called immediately before an inode is freed. We have exclusive
1456 * access to the inode.
1459 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1461 struct buffer_head *bh = NULL;
1463 if (!EXT4_I(inode)->i_file_acl)
1465 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1467 EXT4_ERROR_INODE(inode, "block %llu read error",
1468 EXT4_I(inode)->i_file_acl);
1471 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1472 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1473 EXT4_ERROR_INODE(inode, "bad block %llu",
1474 EXT4_I(inode)->i_file_acl);
1477 ext4_xattr_release_block(handle, inode, bh);
1478 EXT4_I(inode)->i_file_acl = 0;
1485 * ext4_xattr_put_super()
1487 * This is called when a file system is unmounted.
1490 ext4_xattr_put_super(struct super_block *sb)
1492 mb_cache_shrink(sb->s_bdev);
1496 * ext4_xattr_cache_insert()
1498 * Create a new entry in the extended attribute cache, and insert
1499 * it unless such an entry is already in the cache.
1501 * Returns 0, or a negative error number on failure.
1504 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1506 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1507 struct mb_cache_entry *ce;
1510 ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS);
1512 ea_bdebug(bh, "out of memory");
1515 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1517 mb_cache_entry_free(ce);
1518 if (error == -EBUSY) {
1519 ea_bdebug(bh, "already in cache");
1523 ea_bdebug(bh, "inserting [%x]", (int)hash);
1524 mb_cache_entry_release(ce);
1531 * Compare two extended attribute blocks for equality.
1533 * Returns 0 if the blocks are equal, 1 if they differ, and
1534 * a negative error number on errors.
1537 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1538 struct ext4_xattr_header *header2)
1540 struct ext4_xattr_entry *entry1, *entry2;
1542 entry1 = ENTRY(header1+1);
1543 entry2 = ENTRY(header2+1);
1544 while (!IS_LAST_ENTRY(entry1)) {
1545 if (IS_LAST_ENTRY(entry2))
1547 if (entry1->e_hash != entry2->e_hash ||
1548 entry1->e_name_index != entry2->e_name_index ||
1549 entry1->e_name_len != entry2->e_name_len ||
1550 entry1->e_value_size != entry2->e_value_size ||
1551 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1553 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1555 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1556 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1557 le32_to_cpu(entry1->e_value_size)))
1560 entry1 = EXT4_XATTR_NEXT(entry1);
1561 entry2 = EXT4_XATTR_NEXT(entry2);
1563 if (!IS_LAST_ENTRY(entry2))
1569 * ext4_xattr_cache_find()
1571 * Find an identical extended attribute block.
1573 * Returns a pointer to the block found, or NULL if such a block was
1574 * not found or an error occurred.
1576 static struct buffer_head *
1577 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1578 struct mb_cache_entry **pce)
1580 __u32 hash = le32_to_cpu(header->h_hash);
1581 struct mb_cache_entry *ce;
1582 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1584 if (!header->h_hash)
1585 return NULL; /* never share */
1586 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1588 ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev,
1591 struct buffer_head *bh;
1594 if (PTR_ERR(ce) == -EAGAIN)
1598 bh = sb_bread(inode->i_sb, ce->e_block);
1600 EXT4_ERROR_INODE(inode, "block %lu read error",
1601 (unsigned long) ce->e_block);
1602 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1603 EXT4_XATTR_REFCOUNT_MAX) {
1604 ea_idebug(inode, "block %lu refcount %d>=%d",
1605 (unsigned long) ce->e_block,
1606 le32_to_cpu(BHDR(bh)->h_refcount),
1607 EXT4_XATTR_REFCOUNT_MAX);
1608 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1613 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1618 #define NAME_HASH_SHIFT 5
1619 #define VALUE_HASH_SHIFT 16
1622 * ext4_xattr_hash_entry()
1624 * Compute the hash of an extended attribute.
1626 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1627 struct ext4_xattr_entry *entry)
1630 char *name = entry->e_name;
1633 for (n = 0; n < entry->e_name_len; n++) {
1634 hash = (hash << NAME_HASH_SHIFT) ^
1635 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1639 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1640 __le32 *value = (__le32 *)((char *)header +
1641 le16_to_cpu(entry->e_value_offs));
1642 for (n = (le32_to_cpu(entry->e_value_size) +
1643 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1644 hash = (hash << VALUE_HASH_SHIFT) ^
1645 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1646 le32_to_cpu(*value++);
1649 entry->e_hash = cpu_to_le32(hash);
1652 #undef NAME_HASH_SHIFT
1653 #undef VALUE_HASH_SHIFT
1655 #define BLOCK_HASH_SHIFT 16
1658 * ext4_xattr_rehash()
1660 * Re-compute the extended attribute hash value after an entry has changed.
1662 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1663 struct ext4_xattr_entry *entry)
1665 struct ext4_xattr_entry *here;
1668 ext4_xattr_hash_entry(header, entry);
1669 here = ENTRY(header+1);
1670 while (!IS_LAST_ENTRY(here)) {
1671 if (!here->e_hash) {
1672 /* Block is not shared if an entry's hash value == 0 */
1676 hash = (hash << BLOCK_HASH_SHIFT) ^
1677 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1678 le32_to_cpu(here->e_hash);
1679 here = EXT4_XATTR_NEXT(here);
1681 header->h_hash = cpu_to_le32(hash);
1684 #undef BLOCK_HASH_SHIFT
1686 #define HASH_BUCKET_BITS 10
1689 ext4_xattr_create_cache(char *name)
1691 return mb_cache_create(name, HASH_BUCKET_BITS);
1694 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1697 mb_cache_destroy(cache);