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 "ext4_jbd2.h"
63 #ifdef EXT4_XATTR_DEBUG
64 # define ea_idebug(inode, fmt, ...) \
65 printk(KERN_DEBUG "inode %s:%lu: " fmt "\n", \
66 inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
67 # define ea_bdebug(bh, fmt, ...) \
68 printk(KERN_DEBUG "block %pg:%lu: " fmt "\n", \
69 bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
71 # define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
72 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
75 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
76 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
77 struct ext4_xattr_header *,
78 struct mb_cache_entry **);
79 static void ext4_xattr_rehash(struct ext4_xattr_header *,
80 struct ext4_xattr_entry *);
81 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
84 static const struct xattr_handler *ext4_xattr_handler_map[] = {
85 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
86 #ifdef CONFIG_EXT4_FS_POSIX_ACL
87 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
88 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
90 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
91 #ifdef CONFIG_EXT4_FS_SECURITY
92 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
96 const struct xattr_handler *ext4_xattr_handlers[] = {
97 &ext4_xattr_user_handler,
98 &ext4_xattr_trusted_handler,
99 #ifdef CONFIG_EXT4_FS_POSIX_ACL
100 &posix_acl_access_xattr_handler,
101 &posix_acl_default_xattr_handler,
103 #ifdef CONFIG_EXT4_FS_SECURITY
104 &ext4_xattr_security_handler,
109 #define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \
110 inode->i_sb->s_fs_info)->s_mb_cache)
112 static __le32 ext4_xattr_block_csum(struct inode *inode,
114 struct ext4_xattr_header *hdr)
116 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
118 __le64 dsk_block_nr = cpu_to_le64(block_nr);
119 __u32 dummy_csum = 0;
120 int offset = offsetof(struct ext4_xattr_header, h_checksum);
122 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
123 sizeof(dsk_block_nr));
124 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
125 csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
126 offset += sizeof(dummy_csum);
127 csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
128 EXT4_BLOCK_SIZE(inode->i_sb) - offset);
130 return cpu_to_le32(csum);
133 static int ext4_xattr_block_csum_verify(struct inode *inode,
135 struct ext4_xattr_header *hdr)
137 if (ext4_has_metadata_csum(inode->i_sb) &&
138 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
143 static void ext4_xattr_block_csum_set(struct inode *inode,
145 struct ext4_xattr_header *hdr)
147 if (!ext4_has_metadata_csum(inode->i_sb))
150 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
153 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
155 struct buffer_head *bh)
157 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
158 return ext4_handle_dirty_metadata(handle, inode, bh);
161 static inline const struct xattr_handler *
162 ext4_xattr_handler(int name_index)
164 const struct xattr_handler *handler = NULL;
166 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
167 handler = ext4_xattr_handler_map[name_index];
172 * Inode operation listxattr()
174 * d_inode(dentry)->i_mutex: don't care
177 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
179 return ext4_xattr_list(dentry, buffer, size);
183 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
186 struct ext4_xattr_entry *e = entry;
188 while (!IS_LAST_ENTRY(e)) {
189 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
190 if ((void *)next >= end)
191 return -EFSCORRUPTED;
195 while (!IS_LAST_ENTRY(entry)) {
196 if (entry->e_value_block != 0)
197 return -EFSCORRUPTED;
198 if (entry->e_value_size != 0 &&
199 (value_start + le16_to_cpu(entry->e_value_offs) <
200 (void *)e + sizeof(__u32) ||
201 value_start + le16_to_cpu(entry->e_value_offs) +
202 le32_to_cpu(entry->e_value_size) > end))
203 return -EFSCORRUPTED;
204 entry = EXT4_XATTR_NEXT(entry);
211 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
215 if (buffer_verified(bh))
218 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
219 BHDR(bh)->h_blocks != cpu_to_le32(1))
220 return -EFSCORRUPTED;
221 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
223 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
226 set_buffer_verified(bh);
231 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
232 void *end, const char *function, unsigned int line)
234 struct ext4_xattr_entry *entry = IFIRST(header);
235 int error = -EFSCORRUPTED;
237 if (((void *) header >= end) ||
238 (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
240 error = ext4_xattr_check_names(entry, end, entry);
243 __ext4_error_inode(inode, function, line, 0,
244 "corrupted in-inode xattr");
248 #define xattr_check_inode(inode, header, end) \
249 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
252 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
254 size_t value_size = le32_to_cpu(entry->e_value_size);
256 if (entry->e_value_block != 0 || value_size > size ||
257 le16_to_cpu(entry->e_value_offs) + value_size > size)
258 return -EFSCORRUPTED;
263 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
264 const char *name, size_t size, int sorted)
266 struct ext4_xattr_entry *entry;
272 name_len = strlen(name);
274 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
275 cmp = name_index - entry->e_name_index;
277 cmp = name_len - entry->e_name_len;
279 cmp = memcmp(name, entry->e_name, name_len);
280 if (cmp <= 0 && (sorted || cmp == 0))
284 if (!cmp && ext4_xattr_check_entry(entry, size))
285 return -EFSCORRUPTED;
286 return cmp ? -ENODATA : 0;
290 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
291 void *buffer, size_t buffer_size)
293 struct buffer_head *bh = NULL;
294 struct ext4_xattr_entry *entry;
297 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
299 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
300 name_index, name, buffer, (long)buffer_size);
303 if (!EXT4_I(inode)->i_file_acl)
305 ea_idebug(inode, "reading block %llu",
306 (unsigned long long)EXT4_I(inode)->i_file_acl);
307 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
310 ea_bdebug(bh, "b_count=%d, refcount=%d",
311 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
312 if (ext4_xattr_check_block(inode, bh)) {
314 EXT4_ERROR_INODE(inode, "bad block %llu",
315 EXT4_I(inode)->i_file_acl);
316 error = -EFSCORRUPTED;
319 ext4_xattr_cache_insert(ext4_mb_cache, bh);
321 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
322 if (error == -EFSCORRUPTED)
326 size = le32_to_cpu(entry->e_value_size);
329 if (size > buffer_size)
331 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
342 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
343 void *buffer, size_t buffer_size)
345 struct ext4_xattr_ibody_header *header;
346 struct ext4_xattr_entry *entry;
347 struct ext4_inode *raw_inode;
348 struct ext4_iloc iloc;
353 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
355 error = ext4_get_inode_loc(inode, &iloc);
358 raw_inode = ext4_raw_inode(&iloc);
359 header = IHDR(inode, raw_inode);
360 entry = IFIRST(header);
361 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
362 error = xattr_check_inode(inode, header, end);
365 error = ext4_xattr_find_entry(&entry, name_index, name,
366 end - (void *)entry, 0);
369 size = le32_to_cpu(entry->e_value_size);
372 if (size > buffer_size)
374 memcpy(buffer, (void *)IFIRST(header) +
375 le16_to_cpu(entry->e_value_offs), size);
387 * Copy an extended attribute into the buffer
388 * provided, or compute the buffer size required.
389 * Buffer is NULL to compute the size of the buffer required.
391 * Returns a negative error number on failure, or the number of bytes
392 * used / required on success.
395 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
396 void *buffer, size_t buffer_size)
400 if (strlen(name) > 255)
403 down_read(&EXT4_I(inode)->xattr_sem);
404 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
406 if (error == -ENODATA)
407 error = ext4_xattr_block_get(inode, name_index, name, buffer,
409 up_read(&EXT4_I(inode)->xattr_sem);
414 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
415 char *buffer, size_t buffer_size)
417 size_t rest = buffer_size;
419 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
420 const struct xattr_handler *handler =
421 ext4_xattr_handler(entry->e_name_index);
423 if (handler && (!handler->list || handler->list(dentry))) {
424 const char *prefix = handler->prefix ?: handler->name;
425 size_t prefix_len = strlen(prefix);
426 size_t size = prefix_len + entry->e_name_len + 1;
431 memcpy(buffer, prefix, prefix_len);
432 buffer += prefix_len;
433 memcpy(buffer, entry->e_name, entry->e_name_len);
434 buffer += entry->e_name_len;
440 return buffer_size - rest; /* total size */
444 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
446 struct inode *inode = d_inode(dentry);
447 struct buffer_head *bh = NULL;
449 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
451 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
452 buffer, (long)buffer_size);
455 if (!EXT4_I(inode)->i_file_acl)
457 ea_idebug(inode, "reading block %llu",
458 (unsigned long long)EXT4_I(inode)->i_file_acl);
459 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
463 ea_bdebug(bh, "b_count=%d, refcount=%d",
464 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
465 if (ext4_xattr_check_block(inode, bh)) {
466 EXT4_ERROR_INODE(inode, "bad block %llu",
467 EXT4_I(inode)->i_file_acl);
468 error = -EFSCORRUPTED;
471 ext4_xattr_cache_insert(ext4_mb_cache, bh);
472 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
481 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
483 struct inode *inode = d_inode(dentry);
484 struct ext4_xattr_ibody_header *header;
485 struct ext4_inode *raw_inode;
486 struct ext4_iloc iloc;
490 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
492 error = ext4_get_inode_loc(inode, &iloc);
495 raw_inode = ext4_raw_inode(&iloc);
496 header = IHDR(inode, raw_inode);
497 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
498 error = xattr_check_inode(inode, header, end);
501 error = ext4_xattr_list_entries(dentry, IFIRST(header),
502 buffer, buffer_size);
512 * Copy a list of attribute names into the buffer
513 * provided, or compute the buffer size required.
514 * Buffer is NULL to compute the size of the buffer required.
516 * Returns a negative error number on failure, or the number of bytes
517 * used / required on success.
520 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
524 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
525 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
532 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
537 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
542 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
545 static void ext4_xattr_update_super_block(handle_t *handle,
546 struct super_block *sb)
548 if (ext4_has_feature_xattr(sb))
551 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
552 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
553 ext4_set_feature_xattr(sb);
554 ext4_handle_dirty_super(handle, sb);
559 * Release the xattr block BH: If the reference count is > 1, decrement it;
560 * otherwise free the block.
563 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
564 struct buffer_head *bh)
566 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
570 BUFFER_TRACE(bh, "get_write_access");
571 error = ext4_journal_get_write_access(handle, bh);
576 hash = le32_to_cpu(BHDR(bh)->h_hash);
577 ref = le32_to_cpu(BHDR(bh)->h_refcount);
579 ea_bdebug(bh, "refcount now=0; freeing");
581 * This must happen under buffer lock for
582 * ext4_xattr_block_set() to reliably detect freed block
584 mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
587 ext4_free_blocks(handle, inode, bh, 0, 1,
588 EXT4_FREE_BLOCKS_METADATA |
589 EXT4_FREE_BLOCKS_FORGET);
592 BHDR(bh)->h_refcount = cpu_to_le32(ref);
593 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
594 struct mb_cache_entry *ce;
596 ce = mb_cache_entry_get(ext4_mb_cache, hash,
600 mb_cache_entry_put(ext4_mb_cache, ce);
605 * Beware of this ugliness: Releasing of xattr block references
606 * from different inodes can race and so we have to protect
607 * from a race where someone else frees the block (and releases
608 * its journal_head) before we are done dirtying the buffer. In
609 * nojournal mode this race is harmless and we actually cannot
610 * call ext4_handle_dirty_xattr_block() with locked buffer as
611 * that function can call sync_dirty_buffer() so for that case
612 * we handle the dirtying after unlocking the buffer.
614 if (ext4_handle_valid(handle))
615 error = ext4_handle_dirty_xattr_block(handle, inode,
618 if (!ext4_handle_valid(handle))
619 error = ext4_handle_dirty_xattr_block(handle, inode,
622 ext4_handle_sync(handle);
623 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
624 ea_bdebug(bh, "refcount now=%d; releasing",
625 le32_to_cpu(BHDR(bh)->h_refcount));
628 ext4_std_error(inode->i_sb, error);
633 * Find the available free space for EAs. This also returns the total number of
634 * bytes used by EA entries.
636 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
637 size_t *min_offs, void *base, int *total)
639 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
640 if (last->e_value_size) {
641 size_t offs = le16_to_cpu(last->e_value_offs);
642 if (offs < *min_offs)
646 *total += EXT4_XATTR_LEN(last->e_name_len);
648 return (*min_offs - ((void *)last - base) - sizeof(__u32));
652 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
654 struct ext4_xattr_entry *last;
655 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
657 /* Compute min_offs and last. */
659 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
660 if (last->e_value_size) {
661 size_t offs = le16_to_cpu(last->e_value_offs);
666 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
668 if (s->here->e_value_size) {
669 size_t size = le32_to_cpu(s->here->e_value_size);
670 free += EXT4_XATTR_SIZE(size);
672 free += EXT4_XATTR_LEN(name_len);
675 if (free < EXT4_XATTR_LEN(name_len) +
676 EXT4_XATTR_SIZE(i->value_len))
680 if (i->value && s->not_found) {
681 /* Insert the new name. */
682 size_t size = EXT4_XATTR_LEN(name_len);
683 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
684 memmove((void *)s->here + size, s->here, rest);
685 memset(s->here, 0, size);
686 s->here->e_name_index = i->name_index;
687 s->here->e_name_len = name_len;
688 memcpy(s->here->e_name, i->name, name_len);
690 if (s->here->e_value_size) {
691 void *first_val = s->base + min_offs;
692 size_t offs = le16_to_cpu(s->here->e_value_offs);
693 void *val = s->base + offs;
694 size_t size = EXT4_XATTR_SIZE(
695 le32_to_cpu(s->here->e_value_size));
697 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
698 /* The old and the new value have the same
699 size. Just replace. */
700 s->here->e_value_size =
701 cpu_to_le32(i->value_len);
702 if (i->value == EXT4_ZERO_XATTR_VALUE) {
703 memset(val, 0, size);
705 /* Clear pad bytes first. */
706 memset(val + size - EXT4_XATTR_PAD, 0,
708 memcpy(val, i->value, i->value_len);
713 /* Remove the old value. */
714 memmove(first_val + size, first_val, val - first_val);
715 memset(first_val, 0, size);
716 s->here->e_value_size = 0;
717 s->here->e_value_offs = 0;
720 /* Adjust all value offsets. */
722 while (!IS_LAST_ENTRY(last)) {
723 size_t o = le16_to_cpu(last->e_value_offs);
724 if (last->e_value_size && o < offs)
726 cpu_to_le16(o + size);
727 last = EXT4_XATTR_NEXT(last);
731 /* Remove the old name. */
732 size_t size = EXT4_XATTR_LEN(name_len);
733 last = ENTRY((void *)last - size);
734 memmove(s->here, (void *)s->here + size,
735 (void *)last - (void *)s->here + sizeof(__u32));
736 memset(last, 0, size);
741 /* Insert the new value. */
742 s->here->e_value_size = cpu_to_le32(i->value_len);
744 size_t size = EXT4_XATTR_SIZE(i->value_len);
745 void *val = s->base + min_offs - size;
746 s->here->e_value_offs = cpu_to_le16(min_offs - size);
747 if (i->value == EXT4_ZERO_XATTR_VALUE) {
748 memset(val, 0, size);
750 /* Clear the pad bytes first. */
751 memset(val + size - EXT4_XATTR_PAD, 0,
753 memcpy(val, i->value, i->value_len);
760 struct ext4_xattr_block_find {
761 struct ext4_xattr_search s;
762 struct buffer_head *bh;
766 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
767 struct ext4_xattr_block_find *bs)
769 struct super_block *sb = inode->i_sb;
772 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
773 i->name_index, i->name, i->value, (long)i->value_len);
775 if (EXT4_I(inode)->i_file_acl) {
776 /* The inode already has an extended attribute block. */
777 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
781 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
782 atomic_read(&(bs->bh->b_count)),
783 le32_to_cpu(BHDR(bs->bh)->h_refcount));
784 if (ext4_xattr_check_block(inode, bs->bh)) {
785 EXT4_ERROR_INODE(inode, "bad block %llu",
786 EXT4_I(inode)->i_file_acl);
787 error = -EFSCORRUPTED;
790 /* Find the named attribute. */
791 bs->s.base = BHDR(bs->bh);
792 bs->s.first = BFIRST(bs->bh);
793 bs->s.end = bs->bh->b_data + bs->bh->b_size;
794 bs->s.here = bs->s.first;
795 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
796 i->name, bs->bh->b_size, 1);
797 if (error && error != -ENODATA)
799 bs->s.not_found = error;
808 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
809 struct ext4_xattr_info *i,
810 struct ext4_xattr_block_find *bs)
812 struct super_block *sb = inode->i_sb;
813 struct buffer_head *new_bh = NULL;
814 struct ext4_xattr_search *s = &bs->s;
815 struct mb_cache_entry *ce = NULL;
817 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
819 #define header(x) ((struct ext4_xattr_header *)(x))
821 if (i->value && i->value_len > sb->s_blocksize)
824 BUFFER_TRACE(bs->bh, "get_write_access");
825 error = ext4_journal_get_write_access(handle, bs->bh);
830 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
831 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
834 * This must happen under buffer lock for
835 * ext4_xattr_block_set() to reliably detect modified
838 mb_cache_entry_delete_block(ext4_mb_cache, hash,
840 ea_bdebug(bs->bh, "modifying in-place");
841 error = ext4_xattr_set_entry(i, s);
843 if (!IS_LAST_ENTRY(s->first))
844 ext4_xattr_rehash(header(s->base),
846 ext4_xattr_cache_insert(ext4_mb_cache,
849 unlock_buffer(bs->bh);
850 if (error == -EFSCORRUPTED)
853 error = ext4_handle_dirty_xattr_block(handle,
860 int offset = (char *)s->here - bs->bh->b_data;
862 unlock_buffer(bs->bh);
863 ea_bdebug(bs->bh, "cloning");
864 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
868 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
869 s->first = ENTRY(header(s->base)+1);
870 header(s->base)->h_refcount = cpu_to_le32(1);
871 s->here = ENTRY(s->base + offset);
872 s->end = s->base + bs->bh->b_size;
875 /* Allocate a buffer where we construct the new block. */
876 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
877 /* assert(header == s->base) */
881 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
882 header(s->base)->h_blocks = cpu_to_le32(1);
883 header(s->base)->h_refcount = cpu_to_le32(1);
884 s->first = ENTRY(header(s->base)+1);
885 s->here = ENTRY(header(s->base)+1);
886 s->end = s->base + sb->s_blocksize;
889 error = ext4_xattr_set_entry(i, s);
890 if (error == -EFSCORRUPTED)
894 if (!IS_LAST_ENTRY(s->first))
895 ext4_xattr_rehash(header(s->base), s->here);
898 if (!IS_LAST_ENTRY(s->first)) {
899 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
901 /* We found an identical block in the cache. */
902 if (new_bh == bs->bh)
903 ea_bdebug(new_bh, "keeping");
907 /* The old block is released after updating
909 error = dquot_alloc_block(inode,
910 EXT4_C2B(EXT4_SB(sb), 1));
913 BUFFER_TRACE(new_bh, "get_write_access");
914 error = ext4_journal_get_write_access(handle,
920 * We have to be careful about races with
921 * freeing, rehashing or adding references to
922 * xattr block. Once we hold buffer lock xattr
923 * block's state is stable so we can check
924 * whether the block got freed / rehashed or
925 * not. Since we unhash mbcache entry under
926 * buffer lock when freeing / rehashing xattr
927 * block, checking whether entry is still
928 * hashed is reliable. Same rules hold for
929 * e_reusable handling.
931 if (hlist_bl_unhashed(&ce->e_hash_list) ||
934 * Undo everything and check mbcache
937 unlock_buffer(new_bh);
938 dquot_free_block(inode,
939 EXT4_C2B(EXT4_SB(sb),
942 mb_cache_entry_put(ext4_mb_cache, ce);
947 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
948 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
949 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
951 ea_bdebug(new_bh, "reusing; refcount now=%d",
953 unlock_buffer(new_bh);
954 error = ext4_handle_dirty_xattr_block(handle,
960 mb_cache_entry_touch(ext4_mb_cache, ce);
961 mb_cache_entry_put(ext4_mb_cache, ce);
963 } else if (bs->bh && s->base == bs->bh->b_data) {
964 /* We were modifying this block in-place. */
965 ea_bdebug(bs->bh, "keeping this block");
969 /* We need to allocate a new block */
970 ext4_fsblk_t goal, block;
972 goal = ext4_group_first_block_no(sb,
973 EXT4_I(inode)->i_block_group);
975 /* non-extent files can't have physical blocks past 2^32 */
976 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
977 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
979 block = ext4_new_meta_blocks(handle, inode, goal, 0,
984 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
985 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
987 ea_idebug(inode, "creating block %llu",
988 (unsigned long long)block);
990 new_bh = sb_getblk(sb, block);
991 if (unlikely(!new_bh)) {
994 ext4_free_blocks(handle, inode, NULL, block, 1,
995 EXT4_FREE_BLOCKS_METADATA);
999 error = ext4_journal_get_create_access(handle, new_bh);
1001 unlock_buffer(new_bh);
1005 memcpy(new_bh->b_data, s->base, new_bh->b_size);
1006 set_buffer_uptodate(new_bh);
1007 unlock_buffer(new_bh);
1008 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1009 error = ext4_handle_dirty_xattr_block(handle,
1016 /* Update the inode. */
1017 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1019 /* Drop the previous xattr block. */
1020 if (bs->bh && bs->bh != new_bh)
1021 ext4_xattr_release_block(handle, inode, bs->bh);
1026 mb_cache_entry_put(ext4_mb_cache, ce);
1028 if (!(bs->bh && s->base == bs->bh->b_data))
1034 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1038 EXT4_ERROR_INODE(inode, "bad block %llu",
1039 EXT4_I(inode)->i_file_acl);
1045 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
1046 struct ext4_xattr_ibody_find *is)
1048 struct ext4_xattr_ibody_header *header;
1049 struct ext4_inode *raw_inode;
1052 if (EXT4_I(inode)->i_extra_isize == 0)
1054 raw_inode = ext4_raw_inode(&is->iloc);
1055 header = IHDR(inode, raw_inode);
1056 is->s.base = is->s.first = IFIRST(header);
1057 is->s.here = is->s.first;
1058 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1059 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1060 error = xattr_check_inode(inode, header, is->s.end);
1063 /* Find the named attribute. */
1064 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1065 i->name, is->s.end -
1066 (void *)is->s.base, 0);
1067 if (error && error != -ENODATA)
1069 is->s.not_found = error;
1074 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1075 struct ext4_xattr_info *i,
1076 struct ext4_xattr_ibody_find *is)
1078 struct ext4_xattr_ibody_header *header;
1079 struct ext4_xattr_search *s = &is->s;
1082 if (EXT4_I(inode)->i_extra_isize == 0)
1084 error = ext4_xattr_set_entry(i, s);
1086 if (error == -ENOSPC &&
1087 ext4_has_inline_data(inode)) {
1088 error = ext4_try_to_evict_inline_data(handle, inode,
1089 EXT4_XATTR_LEN(strlen(i->name) +
1090 EXT4_XATTR_SIZE(i->value_len)));
1093 error = ext4_xattr_ibody_find(inode, i, is);
1096 error = ext4_xattr_set_entry(i, s);
1101 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1102 if (!IS_LAST_ENTRY(s->first)) {
1103 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1104 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1106 header->h_magic = cpu_to_le32(0);
1107 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1112 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1113 struct ext4_xattr_info *i,
1114 struct ext4_xattr_ibody_find *is)
1116 struct ext4_xattr_ibody_header *header;
1117 struct ext4_xattr_search *s = &is->s;
1120 if (EXT4_I(inode)->i_extra_isize == 0)
1122 error = ext4_xattr_set_entry(i, s);
1125 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1126 if (!IS_LAST_ENTRY(s->first)) {
1127 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1128 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1130 header->h_magic = cpu_to_le32(0);
1131 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1136 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
1137 struct ext4_xattr_info *i)
1141 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
1143 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
1144 return !memcmp(value, i->value, i->value_len);
1148 * ext4_xattr_set_handle()
1150 * Create, replace or remove an extended attribute for this inode. Value
1151 * is NULL to remove an existing extended attribute, and non-NULL to
1152 * either replace an existing extended attribute, or create a new extended
1153 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1154 * specify that an extended attribute must exist and must not exist
1155 * previous to the call, respectively.
1157 * Returns 0, or a negative error number on failure.
1160 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1161 const char *name, const void *value, size_t value_len,
1164 struct ext4_xattr_info i = {
1165 .name_index = name_index,
1168 .value_len = value_len,
1171 struct ext4_xattr_ibody_find is = {
1172 .s = { .not_found = -ENODATA, },
1174 struct ext4_xattr_block_find bs = {
1175 .s = { .not_found = -ENODATA, },
1177 unsigned long no_expand;
1182 if (strlen(name) > 255)
1184 down_write(&EXT4_I(inode)->xattr_sem);
1185 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1186 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1188 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1192 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1193 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1194 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1195 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1198 error = ext4_xattr_ibody_find(inode, &i, &is);
1202 error = ext4_xattr_block_find(inode, &i, &bs);
1205 if (is.s.not_found && bs.s.not_found) {
1207 if (flags & XATTR_REPLACE)
1214 if (flags & XATTR_CREATE)
1218 if (!is.s.not_found)
1219 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1220 else if (!bs.s.not_found)
1221 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1224 /* Xattr value did not change? Save us some work and bail out */
1225 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
1227 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
1230 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1231 if (!error && !bs.s.not_found) {
1233 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1234 } else if (error == -ENOSPC) {
1235 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1236 error = ext4_xattr_block_find(inode, &i, &bs);
1240 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1243 if (!is.s.not_found) {
1245 error = ext4_xattr_ibody_set(handle, inode, &i,
1251 ext4_xattr_update_super_block(handle, inode->i_sb);
1252 inode->i_ctime = ext4_current_time(inode);
1254 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1255 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1257 * The bh is consumed by ext4_mark_iloc_dirty, even with
1262 ext4_handle_sync(handle);
1269 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1270 up_write(&EXT4_I(inode)->xattr_sem);
1277 * Like ext4_xattr_set_handle, but start from an inode. This extended
1278 * attribute modification is a filesystem transaction by itself.
1280 * Returns 0, or a negative error number on failure.
1283 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1284 const void *value, size_t value_len, int flags)
1287 int error, retries = 0;
1288 int credits = ext4_jbd2_credits_xattr(inode);
1291 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1292 if (IS_ERR(handle)) {
1293 error = PTR_ERR(handle);
1297 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1298 value, value_len, flags);
1299 error2 = ext4_journal_stop(handle);
1300 if (error == -ENOSPC &&
1301 ext4_should_retry_alloc(inode->i_sb, &retries))
1311 * Shift the EA entries in the inode to create space for the increased
1314 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1315 int value_offs_shift, void *to,
1316 void *from, size_t n)
1318 struct ext4_xattr_entry *last = entry;
1321 /* We always shift xattr headers further thus offsets get lower */
1322 BUG_ON(value_offs_shift > 0);
1324 /* Adjust the value offsets of the entries */
1325 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1326 if (last->e_value_size) {
1327 new_offs = le16_to_cpu(last->e_value_offs) +
1329 last->e_value_offs = cpu_to_le16(new_offs);
1332 /* Shift the entries by n bytes */
1333 memmove(to, from, n);
1337 * Move xattr pointed to by 'entry' from inode into external xattr block
1339 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
1340 struct ext4_inode *raw_inode,
1341 struct ext4_xattr_entry *entry)
1343 struct ext4_xattr_ibody_find *is = NULL;
1344 struct ext4_xattr_block_find *bs = NULL;
1345 char *buffer = NULL, *b_entry_name = NULL;
1346 size_t value_offs, value_size;
1347 struct ext4_xattr_info i = {
1350 .name_index = entry->e_name_index,
1352 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1355 value_offs = le16_to_cpu(entry->e_value_offs);
1356 value_size = le32_to_cpu(entry->e_value_size);
1358 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1359 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1360 buffer = kmalloc(value_size, GFP_NOFS);
1361 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1362 if (!is || !bs || !buffer || !b_entry_name) {
1367 is->s.not_found = -ENODATA;
1368 bs->s.not_found = -ENODATA;
1372 /* Save the entry name and the entry value */
1373 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
1374 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1375 b_entry_name[entry->e_name_len] = '\0';
1376 i.name = b_entry_name;
1378 error = ext4_get_inode_loc(inode, &is->iloc);
1382 error = ext4_xattr_ibody_find(inode, &i, is);
1386 /* Remove the chosen entry from the inode */
1387 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1391 i.name = b_entry_name;
1393 i.value_len = value_size;
1394 error = ext4_xattr_block_find(inode, &i, bs);
1398 /* Add entry which was removed from the inode into the block */
1399 error = ext4_xattr_block_set(handle, inode, &i, bs);
1404 kfree(b_entry_name);
1407 brelse(is->iloc.bh);
1414 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
1415 struct ext4_inode *raw_inode,
1416 int isize_diff, size_t ifree,
1417 size_t bfree, int *total_ino)
1419 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1420 struct ext4_xattr_entry *small_entry;
1421 struct ext4_xattr_entry *entry;
1422 struct ext4_xattr_entry *last;
1423 unsigned int entry_size; /* EA entry size */
1424 unsigned int total_size; /* EA entry size + value size */
1425 unsigned int min_total_size;
1428 while (isize_diff > ifree) {
1431 min_total_size = ~0U;
1432 last = IFIRST(header);
1433 /* Find the entry best suited to be pushed into EA block */
1434 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1436 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1437 EXT4_XATTR_LEN(last->e_name_len);
1438 if (total_size <= bfree &&
1439 total_size < min_total_size) {
1440 if (total_size + ifree < isize_diff) {
1444 min_total_size = total_size;
1449 if (entry == NULL) {
1450 if (small_entry == NULL)
1452 entry = small_entry;
1455 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1456 total_size = entry_size +
1457 EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
1458 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
1463 *total_ino -= entry_size;
1464 ifree += total_size;
1465 bfree -= total_size;
1472 * Expand an inode by new_extra_isize bytes when EAs are present.
1473 * Returns 0 on success or negative error number on failure.
1475 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1476 struct ext4_inode *raw_inode, handle_t *handle)
1478 struct ext4_xattr_ibody_header *header;
1479 struct buffer_head *bh = NULL;
1481 size_t ifree, bfree;
1484 int error = 0, tried_min_extra_isize = 0;
1485 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1486 int isize_diff; /* How much do we need to grow i_extra_isize */
1488 down_write(&EXT4_I(inode)->xattr_sem);
1490 * Set EXT4_STATE_NO_EXPAND to avoid recursion when marking inode dirty
1492 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1494 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
1495 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
1498 header = IHDR(inode, raw_inode);
1501 * Check if enough free space is available in the inode to shift the
1502 * entries ahead by new_extra_isize.
1505 base = IFIRST(header);
1506 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1507 min_offs = end - base;
1508 total_ino = sizeof(struct ext4_xattr_ibody_header);
1510 error = xattr_check_inode(inode, header, end);
1514 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
1515 if (ifree >= isize_diff)
1519 * Enough free space isn't available in the inode, check if
1520 * EA block can hold new_extra_isize bytes.
1522 if (EXT4_I(inode)->i_file_acl) {
1523 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1527 if (ext4_xattr_check_block(inode, bh)) {
1528 EXT4_ERROR_INODE(inode, "bad block %llu",
1529 EXT4_I(inode)->i_file_acl);
1530 error = -EFSCORRUPTED;
1534 end = bh->b_data + bh->b_size;
1535 min_offs = end - base;
1536 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
1538 if (bfree + ifree < isize_diff) {
1539 if (!tried_min_extra_isize && s_min_extra_isize) {
1540 tried_min_extra_isize++;
1541 new_extra_isize = s_min_extra_isize;
1549 bfree = inode->i_sb->s_blocksize;
1552 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
1553 isize_diff, ifree, bfree,
1556 if (error == -ENOSPC && !tried_min_extra_isize &&
1557 s_min_extra_isize) {
1558 tried_min_extra_isize++;
1559 new_extra_isize = s_min_extra_isize;
1566 /* Adjust the offsets and shift the remaining entries ahead */
1567 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
1568 - new_extra_isize, (void *)raw_inode +
1569 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1570 (void *)header, total_ino);
1571 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1574 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1575 up_write(&EXT4_I(inode)->xattr_sem);
1581 * We deliberately leave EXT4_STATE_NO_EXPAND set here since inode
1582 * size expansion failed.
1584 up_write(&EXT4_I(inode)->xattr_sem);
1591 * ext4_xattr_delete_inode()
1593 * Free extended attribute resources associated with this inode. This
1594 * is called immediately before an inode is freed. We have exclusive
1595 * access to the inode.
1598 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1600 struct buffer_head *bh = NULL;
1602 if (!EXT4_I(inode)->i_file_acl)
1604 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1606 EXT4_ERROR_INODE(inode, "block %llu read error",
1607 EXT4_I(inode)->i_file_acl);
1610 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1611 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1612 EXT4_ERROR_INODE(inode, "bad block %llu",
1613 EXT4_I(inode)->i_file_acl);
1616 ext4_xattr_release_block(handle, inode, bh);
1617 EXT4_I(inode)->i_file_acl = 0;
1624 * ext4_xattr_cache_insert()
1626 * Create a new entry in the extended attribute cache, and insert
1627 * it unless such an entry is already in the cache.
1629 * Returns 0, or a negative error number on failure.
1632 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1634 struct ext4_xattr_header *header = BHDR(bh);
1635 __u32 hash = le32_to_cpu(header->h_hash);
1636 int reusable = le32_to_cpu(header->h_refcount) <
1637 EXT4_XATTR_REFCOUNT_MAX;
1640 error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1641 bh->b_blocknr, reusable);
1643 if (error == -EBUSY)
1644 ea_bdebug(bh, "already in cache");
1646 ea_bdebug(bh, "inserting [%x]", (int)hash);
1652 * Compare two extended attribute blocks for equality.
1654 * Returns 0 if the blocks are equal, 1 if they differ, and
1655 * a negative error number on errors.
1658 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1659 struct ext4_xattr_header *header2)
1661 struct ext4_xattr_entry *entry1, *entry2;
1663 entry1 = ENTRY(header1+1);
1664 entry2 = ENTRY(header2+1);
1665 while (!IS_LAST_ENTRY(entry1)) {
1666 if (IS_LAST_ENTRY(entry2))
1668 if (entry1->e_hash != entry2->e_hash ||
1669 entry1->e_name_index != entry2->e_name_index ||
1670 entry1->e_name_len != entry2->e_name_len ||
1671 entry1->e_value_size != entry2->e_value_size ||
1672 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1674 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1675 return -EFSCORRUPTED;
1676 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1677 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1678 le32_to_cpu(entry1->e_value_size)))
1681 entry1 = EXT4_XATTR_NEXT(entry1);
1682 entry2 = EXT4_XATTR_NEXT(entry2);
1684 if (!IS_LAST_ENTRY(entry2))
1690 * ext4_xattr_cache_find()
1692 * Find an identical extended attribute block.
1694 * Returns a pointer to the block found, or NULL if such a block was
1695 * not found or an error occurred.
1697 static struct buffer_head *
1698 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1699 struct mb_cache_entry **pce)
1701 __u32 hash = le32_to_cpu(header->h_hash);
1702 struct mb_cache_entry *ce;
1703 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1705 if (!header->h_hash)
1706 return NULL; /* never share */
1707 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1708 ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1710 struct buffer_head *bh;
1712 bh = sb_bread(inode->i_sb, ce->e_block);
1714 EXT4_ERROR_INODE(inode, "block %lu read error",
1715 (unsigned long) ce->e_block);
1716 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1721 ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1726 #define NAME_HASH_SHIFT 5
1727 #define VALUE_HASH_SHIFT 16
1730 * ext4_xattr_hash_entry()
1732 * Compute the hash of an extended attribute.
1734 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1735 struct ext4_xattr_entry *entry)
1738 char *name = entry->e_name;
1741 for (n = 0; n < entry->e_name_len; n++) {
1742 hash = (hash << NAME_HASH_SHIFT) ^
1743 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1747 if (entry->e_value_size != 0) {
1748 __le32 *value = (__le32 *)((char *)header +
1749 le16_to_cpu(entry->e_value_offs));
1750 for (n = (le32_to_cpu(entry->e_value_size) +
1751 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1752 hash = (hash << VALUE_HASH_SHIFT) ^
1753 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1754 le32_to_cpu(*value++);
1757 entry->e_hash = cpu_to_le32(hash);
1760 #undef NAME_HASH_SHIFT
1761 #undef VALUE_HASH_SHIFT
1763 #define BLOCK_HASH_SHIFT 16
1766 * ext4_xattr_rehash()
1768 * Re-compute the extended attribute hash value after an entry has changed.
1770 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1771 struct ext4_xattr_entry *entry)
1773 struct ext4_xattr_entry *here;
1776 ext4_xattr_hash_entry(header, entry);
1777 here = ENTRY(header+1);
1778 while (!IS_LAST_ENTRY(here)) {
1779 if (!here->e_hash) {
1780 /* Block is not shared if an entry's hash value == 0 */
1784 hash = (hash << BLOCK_HASH_SHIFT) ^
1785 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1786 le32_to_cpu(here->e_hash);
1787 here = EXT4_XATTR_NEXT(here);
1789 header->h_hash = cpu_to_le32(hash);
1792 #undef BLOCK_HASH_SHIFT
1794 #define HASH_BUCKET_BITS 10
1797 ext4_xattr_create_cache(void)
1799 return mb_cache_create(HASH_BUCKET_BITS);
1802 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1805 mb_cache_destroy(cache);