2 * linux/fs/ext2/xattr.c
4 * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Extended attributes for symlinks and special files added per
8 * suggestion of Luka Renko <luka.renko@hermes.si>.
9 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
15 * Extended attributes are stored on disk blocks allocated outside of
16 * any inode. The i_file_acl field is then made to point to this allocated
17 * block. If all extended attributes of an inode are identical, these
18 * inodes may share the same extended attribute block. Such situations
19 * are automatically detected by keeping a cache of recent attribute block
20 * numbers and hashes over the block's contents in memory.
23 * Extended attribute block layout:
25 * +------------------+
28 * | entry 2 | | growing downwards
33 * | value 3 | | growing upwards
35 * +------------------+
37 * The block header is followed by multiple entry descriptors. These entry
38 * descriptors are variable in size, and alligned to EXT2_XATTR_PAD
39 * byte boundaries. The entry descriptors are sorted by attribute name,
40 * so that two extended attribute blocks can be compared efficiently.
42 * Attribute values are aligned to the end of the block, stored in
43 * no specific order. They are also padded to EXT2_XATTR_PAD byte
44 * boundaries. No additional gaps are left between them.
48 * EXT2_I(inode)->i_file_acl is protected by EXT2_I(inode)->xattr_sem.
49 * EA blocks are only changed if they are exclusive to an inode, so
50 * holding xattr_sem also means that nothing but the EA block's reference
51 * count will change. Multiple writers to an EA block are synchronized
52 * by the bh lock. No more than a single bh lock is held at any time
56 #include <linux/buffer_head.h>
57 #include <linux/module.h>
58 #include <linux/init.h>
59 #include <linux/slab.h>
60 #include <linux/mbcache.h>
61 #include <linux/quotaops.h>
62 #include <linux/rwsem.h>
63 #include <linux/vs_dlimit.h>
68 #define HDR(bh) ((struct ext2_xattr_header *)((bh)->b_data))
69 #define ENTRY(ptr) ((struct ext2_xattr_entry *)(ptr))
70 #define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1)
71 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
73 #ifdef EXT2_XATTR_DEBUG
74 # define ea_idebug(inode, f...) do { \
75 printk(KERN_DEBUG "inode %s:%ld: ", \
76 inode->i_sb->s_id, inode->i_ino); \
80 # define ea_bdebug(bh, f...) do { \
81 char b[BDEVNAME_SIZE]; \
82 printk(KERN_DEBUG "block %s:%lu: ", \
83 bdevname(bh->b_bdev, b), \
84 (unsigned long) bh->b_blocknr); \
89 # define ea_idebug(f...)
90 # define ea_bdebug(f...)
93 static int ext2_xattr_set2(struct inode *, struct buffer_head *,
94 struct ext2_xattr_header *);
96 static int ext2_xattr_cache_insert(struct buffer_head *);
97 static struct buffer_head *ext2_xattr_cache_find(struct inode *,
98 struct ext2_xattr_header *);
99 static void ext2_xattr_rehash(struct ext2_xattr_header *,
100 struct ext2_xattr_entry *);
102 static struct mb_cache *ext2_xattr_cache;
104 static struct xattr_handler *ext2_xattr_handler_map[] = {
105 [EXT2_XATTR_INDEX_USER] = &ext2_xattr_user_handler,
106 #ifdef CONFIG_EXT2_FS_POSIX_ACL
107 [EXT2_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext2_xattr_acl_access_handler,
108 [EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext2_xattr_acl_default_handler,
110 [EXT2_XATTR_INDEX_TRUSTED] = &ext2_xattr_trusted_handler,
111 #ifdef CONFIG_EXT2_FS_SECURITY
112 [EXT2_XATTR_INDEX_SECURITY] = &ext2_xattr_security_handler,
116 struct xattr_handler *ext2_xattr_handlers[] = {
117 &ext2_xattr_user_handler,
118 &ext2_xattr_trusted_handler,
119 #ifdef CONFIG_EXT2_FS_POSIX_ACL
120 &ext2_xattr_acl_access_handler,
121 &ext2_xattr_acl_default_handler,
123 #ifdef CONFIG_EXT2_FS_SECURITY
124 &ext2_xattr_security_handler,
129 static inline struct xattr_handler *
130 ext2_xattr_handler(int name_index)
132 struct xattr_handler *handler = NULL;
134 if (name_index > 0 && name_index < ARRAY_SIZE(ext2_xattr_handler_map))
135 handler = ext2_xattr_handler_map[name_index];
142 * Copy an extended attribute into the buffer
143 * provided, or compute the buffer size required.
144 * Buffer is NULL to compute the size of the buffer required.
146 * Returns a negative error number on failure, or the number of bytes
147 * used / required on success.
150 ext2_xattr_get(struct inode *inode, int name_index, const char *name,
151 void *buffer, size_t buffer_size)
153 struct buffer_head *bh = NULL;
154 struct ext2_xattr_entry *entry;
155 size_t name_len, size;
159 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
160 name_index, name, buffer, (long)buffer_size);
164 down_read(&EXT2_I(inode)->xattr_sem);
166 if (!EXT2_I(inode)->i_file_acl)
168 ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl);
169 bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
173 ea_bdebug(bh, "b_count=%d, refcount=%d",
174 atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
175 end = bh->b_data + bh->b_size;
176 if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
177 HDR(bh)->h_blocks != cpu_to_le32(1)) {
178 bad_block: ext2_error(inode->i_sb, "ext2_xattr_get",
179 "inode %ld: bad block %d", inode->i_ino,
180 EXT2_I(inode)->i_file_acl);
184 /* find named attribute */
185 name_len = strlen(name);
190 entry = FIRST_ENTRY(bh);
191 while (!IS_LAST_ENTRY(entry)) {
192 struct ext2_xattr_entry *next =
193 EXT2_XATTR_NEXT(entry);
194 if ((char *)next >= end)
196 if (name_index == entry->e_name_index &&
197 name_len == entry->e_name_len &&
198 memcmp(name, entry->e_name, name_len) == 0)
202 /* Check the remaining name entries */
203 while (!IS_LAST_ENTRY(entry)) {
204 struct ext2_xattr_entry *next =
205 EXT2_XATTR_NEXT(entry);
206 if ((char *)next >= end)
210 if (ext2_xattr_cache_insert(bh))
211 ea_idebug(inode, "cache insert failed");
215 /* check the buffer size */
216 if (entry->e_value_block != 0)
218 size = le32_to_cpu(entry->e_value_size);
219 if (size > inode->i_sb->s_blocksize ||
220 le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize)
223 if (ext2_xattr_cache_insert(bh))
224 ea_idebug(inode, "cache insert failed");
227 if (size > buffer_size)
229 /* return value of attribute */
230 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
237 up_read(&EXT2_I(inode)->xattr_sem);
245 * Copy a list of attribute names into the buffer
246 * provided, or compute the buffer size required.
247 * Buffer is NULL to compute the size of the buffer required.
249 * Returns a negative error number on failure, or the number of bytes
250 * used / required on success.
253 ext2_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
255 struct buffer_head *bh = NULL;
256 struct ext2_xattr_entry *entry;
258 size_t rest = buffer_size;
261 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
262 buffer, (long)buffer_size);
264 down_read(&EXT2_I(inode)->xattr_sem);
266 if (!EXT2_I(inode)->i_file_acl)
268 ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl);
269 bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
273 ea_bdebug(bh, "b_count=%d, refcount=%d",
274 atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
275 end = bh->b_data + bh->b_size;
276 if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
277 HDR(bh)->h_blocks != cpu_to_le32(1)) {
278 bad_block: ext2_error(inode->i_sb, "ext2_xattr_list",
279 "inode %ld: bad block %d", inode->i_ino,
280 EXT2_I(inode)->i_file_acl);
285 /* check the on-disk data structure */
286 entry = FIRST_ENTRY(bh);
287 while (!IS_LAST_ENTRY(entry)) {
288 struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry);
290 if ((char *)next >= end)
294 if (ext2_xattr_cache_insert(bh))
295 ea_idebug(inode, "cache insert failed");
297 /* list the attribute names */
298 for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry);
299 entry = EXT2_XATTR_NEXT(entry)) {
300 struct xattr_handler *handler =
301 ext2_xattr_handler(entry->e_name_index);
304 size_t size = handler->list(inode, buffer, rest,
317 error = buffer_size - rest; /* total size */
321 up_read(&EXT2_I(inode)->xattr_sem);
327 * Inode operation listxattr()
329 * dentry->d_inode->i_sem: don't care
332 ext2_listxattr(struct dentry *dentry, char *buffer, size_t size)
334 return ext2_xattr_list(dentry->d_inode, buffer, size);
338 * If the EXT2_FEATURE_COMPAT_EXT_ATTR feature of this file system is
341 static void ext2_xattr_update_super_block(struct super_block *sb)
343 if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR))
347 EXT2_SB(sb)->s_es->s_feature_compat |=
348 cpu_to_le32(EXT2_FEATURE_COMPAT_EXT_ATTR);
350 mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
357 * Create, replace or remove an extended attribute for this inode. Buffer
358 * is NULL to remove an existing extended attribute, and non-NULL to
359 * either replace an existing extended attribute, or create a new extended
360 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
361 * specify that an extended attribute must exist and must not exist
362 * previous to the call, respectively.
364 * Returns 0, or a negative error number on failure.
367 ext2_xattr_set(struct inode *inode, int name_index, const char *name,
368 const void *value, size_t value_len, int flags)
370 struct super_block *sb = inode->i_sb;
371 struct buffer_head *bh = NULL;
372 struct ext2_xattr_header *header = NULL;
373 struct ext2_xattr_entry *here, *last;
374 size_t name_len, free, min_offs = sb->s_blocksize;
375 int not_found = 1, error;
379 * header -- Points either into bh, or to a temporarily
381 * here -- The named entry found, or the place for inserting, within
382 * the block pointed to by header.
383 * last -- Points right after the last named entry within the block
384 * pointed to by header.
385 * min_offs -- The offset of the first value (values are aligned
386 * towards the end of the block).
387 * end -- Points right after the block pointed to by header.
390 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
391 name_index, name, value, (long)value_len);
393 if (IS_RDONLY(inode))
395 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
401 name_len = strlen(name);
402 if (name_len > 255 || value_len > sb->s_blocksize)
404 down_write(&EXT2_I(inode)->xattr_sem);
405 if (EXT2_I(inode)->i_file_acl) {
406 /* The inode already has an extended attribute block. */
407 bh = sb_bread(sb, EXT2_I(inode)->i_file_acl);
411 ea_bdebug(bh, "b_count=%d, refcount=%d",
412 atomic_read(&(bh->b_count)),
413 le32_to_cpu(HDR(bh)->h_refcount));
415 end = bh->b_data + bh->b_size;
416 if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
417 header->h_blocks != cpu_to_le32(1)) {
418 bad_block: ext2_error(sb, "ext2_xattr_set",
419 "inode %ld: bad block %d", inode->i_ino,
420 EXT2_I(inode)->i_file_acl);
424 /* Find the named attribute. */
425 here = FIRST_ENTRY(bh);
426 while (!IS_LAST_ENTRY(here)) {
427 struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(here);
428 if ((char *)next >= end)
430 if (!here->e_value_block && here->e_value_size) {
431 size_t offs = le16_to_cpu(here->e_value_offs);
435 not_found = name_index - here->e_name_index;
437 not_found = name_len - here->e_name_len;
439 not_found = memcmp(name, here->e_name,name_len);
445 /* We still need to compute min_offs and last. */
446 while (!IS_LAST_ENTRY(last)) {
447 struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last);
448 if ((char *)next >= end)
450 if (!last->e_value_block && last->e_value_size) {
451 size_t offs = le16_to_cpu(last->e_value_offs);
458 /* Check whether we have enough space left. */
459 free = min_offs - ((char*)last - (char*)header) - sizeof(__u32);
461 /* We will use a new extended attribute block. */
462 free = sb->s_blocksize -
463 sizeof(struct ext2_xattr_header) - sizeof(__u32);
464 here = last = NULL; /* avoid gcc uninitialized warning. */
468 /* Request to remove a nonexistent attribute? */
470 if (flags & XATTR_REPLACE)
476 /* Request to create an existing attribute? */
478 if (flags & XATTR_CREATE)
480 if (!here->e_value_block && here->e_value_size) {
481 size_t size = le32_to_cpu(here->e_value_size);
483 if (le16_to_cpu(here->e_value_offs) + size >
484 sb->s_blocksize || size > sb->s_blocksize)
486 free += EXT2_XATTR_SIZE(size);
488 free += EXT2_XATTR_LEN(name_len);
491 if (free < EXT2_XATTR_LEN(name_len) + EXT2_XATTR_SIZE(value_len))
494 /* Here we know that we can set the new attribute. */
497 struct mb_cache_entry *ce;
499 /* assert(header == HDR(bh)); */
500 ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev,
503 if (header->h_refcount == cpu_to_le32(1)) {
504 ea_bdebug(bh, "modifying in-place");
506 mb_cache_entry_free(ce);
507 /* keep the buffer locked while modifying it. */
512 mb_cache_entry_release(ce);
514 ea_bdebug(bh, "cloning");
515 header = kmalloc(bh->b_size, GFP_KERNEL);
519 memcpy(header, HDR(bh), bh->b_size);
520 header->h_refcount = cpu_to_le32(1);
522 offset = (char *)here - bh->b_data;
523 here = ENTRY((char *)header + offset);
524 offset = (char *)last - bh->b_data;
525 last = ENTRY((char *)header + offset);
528 /* Allocate a buffer where we construct the new block. */
529 header = kmalloc(sb->s_blocksize, GFP_KERNEL);
533 memset(header, 0, sb->s_blocksize);
534 end = (char *)header + sb->s_blocksize;
535 header->h_magic = cpu_to_le32(EXT2_XATTR_MAGIC);
536 header->h_blocks = header->h_refcount = cpu_to_le32(1);
537 last = here = ENTRY(header+1);
540 /* Iff we are modifying the block in-place, bh is locked here. */
543 /* Insert the new name. */
544 size_t size = EXT2_XATTR_LEN(name_len);
545 size_t rest = (char *)last - (char *)here;
546 memmove((char *)here + size, here, rest);
547 memset(here, 0, size);
548 here->e_name_index = name_index;
549 here->e_name_len = name_len;
550 memcpy(here->e_name, name, name_len);
552 if (!here->e_value_block && here->e_value_size) {
553 char *first_val = (char *)header + min_offs;
554 size_t offs = le16_to_cpu(here->e_value_offs);
555 char *val = (char *)header + offs;
556 size_t size = EXT2_XATTR_SIZE(
557 le32_to_cpu(here->e_value_size));
559 if (size == EXT2_XATTR_SIZE(value_len)) {
560 /* The old and the new value have the same
561 size. Just replace. */
562 here->e_value_size = cpu_to_le32(value_len);
563 memset(val + size - EXT2_XATTR_PAD, 0,
564 EXT2_XATTR_PAD); /* Clear pad bytes. */
565 memcpy(val, value, value_len);
569 /* Remove the old value. */
570 memmove(first_val + size, first_val, val - first_val);
571 memset(first_val, 0, size);
572 here->e_value_offs = 0;
575 /* Adjust all value offsets. */
576 last = ENTRY(header+1);
577 while (!IS_LAST_ENTRY(last)) {
578 size_t o = le16_to_cpu(last->e_value_offs);
579 if (!last->e_value_block && o < offs)
581 cpu_to_le16(o + size);
582 last = EXT2_XATTR_NEXT(last);
586 /* Remove the old name. */
587 size_t size = EXT2_XATTR_LEN(name_len);
588 last = ENTRY((char *)last - size);
589 memmove(here, (char*)here + size,
590 (char*)last - (char*)here);
591 memset(last, 0, size);
596 /* Insert the new value. */
597 here->e_value_size = cpu_to_le32(value_len);
599 size_t size = EXT2_XATTR_SIZE(value_len);
600 char *val = (char *)header + min_offs - size;
602 cpu_to_le16((char *)val - (char *)header);
603 memset(val + size - EXT2_XATTR_PAD, 0,
604 EXT2_XATTR_PAD); /* Clear the pad bytes. */
605 memcpy(val, value, value_len);
610 if (IS_LAST_ENTRY(ENTRY(header+1))) {
611 /* This block is now empty. */
612 if (bh && header == HDR(bh))
613 unlock_buffer(bh); /* we were modifying in-place. */
614 error = ext2_xattr_set2(inode, bh, NULL);
616 ext2_xattr_rehash(header, here);
617 if (bh && header == HDR(bh))
618 unlock_buffer(bh); /* we were modifying in-place. */
619 error = ext2_xattr_set2(inode, bh, header);
624 if (!(bh && header == HDR(bh)))
626 up_write(&EXT2_I(inode)->xattr_sem);
632 * Second half of ext2_xattr_set(): Update the file system.
635 ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
636 struct ext2_xattr_header *header)
638 struct super_block *sb = inode->i_sb;
639 struct buffer_head *new_bh = NULL;
643 new_bh = ext2_xattr_cache_find(inode, header);
645 /* We found an identical block in the cache. */
646 if (new_bh == old_bh) {
647 ea_bdebug(new_bh, "keeping this block");
649 /* The old block is released after updating
651 ea_bdebug(new_bh, "reusing block");
654 if (DLIMIT_ALLOC_BLOCK(sb, inode->i_xid, 1))
657 if (DQUOT_ALLOC_BLOCK(inode, 1)) {
658 DLIMIT_FREE_BLOCK(sb, inode->i_xid, 1);
659 unlock_buffer(new_bh);
662 HDR(new_bh)->h_refcount = cpu_to_le32(1 +
663 le32_to_cpu(HDR(new_bh)->h_refcount));
664 ea_bdebug(new_bh, "refcount now=%d",
665 le32_to_cpu(HDR(new_bh)->h_refcount));
667 unlock_buffer(new_bh);
668 } else if (old_bh && header == HDR(old_bh)) {
669 /* Keep this block. No need to lock the block as we
670 don't need to change the reference count. */
673 ext2_xattr_cache_insert(new_bh);
675 /* We need to allocate a new block */
676 int goal = le32_to_cpu(EXT2_SB(sb)->s_es->
677 s_first_data_block) +
678 EXT2_I(inode)->i_block_group *
679 EXT2_BLOCKS_PER_GROUP(sb);
680 int block = ext2_new_block(inode, goal,
684 ea_idebug(inode, "creating block %d", block);
686 new_bh = sb_getblk(sb, block);
688 ext2_free_blocks(inode, block, 1);
693 memcpy(new_bh->b_data, header, new_bh->b_size);
694 set_buffer_uptodate(new_bh);
695 unlock_buffer(new_bh);
696 ext2_xattr_cache_insert(new_bh);
698 ext2_xattr_update_super_block(sb);
700 mark_buffer_dirty(new_bh);
701 if (IS_SYNC(inode)) {
702 sync_dirty_buffer(new_bh);
704 if (buffer_req(new_bh) && !buffer_uptodate(new_bh))
709 /* Update the inode. */
710 EXT2_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
711 inode->i_ctime = CURRENT_TIME_SEC;
712 if (IS_SYNC(inode)) {
713 error = ext2_sync_inode (inode);
714 /* In case sync failed due to ENOSPC the inode was actually
715 * written (only some dirty data were not) so we just proceed
716 * as if nothing happened and cleanup the unused block */
717 if (error && error != -ENOSPC) {
718 if (new_bh && new_bh != old_bh)
719 DQUOT_FREE_BLOCK(inode, 1);
723 mark_inode_dirty(inode);
726 if (old_bh && old_bh != new_bh) {
727 struct mb_cache_entry *ce;
730 * If there was an old block and we are no longer using it,
731 * release the old block.
733 ce = mb_cache_entry_get(ext2_xattr_cache, old_bh->b_bdev,
736 if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) {
737 /* Free the old block. */
739 mb_cache_entry_free(ce);
740 ea_bdebug(old_bh, "freeing");
741 ext2_free_blocks(inode, old_bh->b_blocknr, 1);
742 /* We let our caller release old_bh, so we
743 * need to duplicate the buffer before. */
747 /* Decrement the refcount only. */
748 HDR(old_bh)->h_refcount = cpu_to_le32(
749 le32_to_cpu(HDR(old_bh)->h_refcount) - 1);
751 mb_cache_entry_release(ce);
752 DLIMIT_FREE_BLOCK(sb, inode->i_xid, 1);
753 DQUOT_FREE_BLOCK(inode, 1);
754 mark_buffer_dirty(old_bh);
755 ea_bdebug(old_bh, "refcount now=%d",
756 le32_to_cpu(HDR(old_bh)->h_refcount));
758 unlock_buffer(old_bh);
768 * ext2_xattr_delete_inode()
770 * Free extended attribute resources associated with this inode. This
771 * is called immediately before an inode is freed.
774 ext2_xattr_delete_inode(struct inode *inode)
776 struct buffer_head *bh = NULL;
777 struct mb_cache_entry *ce;
779 down_write(&EXT2_I(inode)->xattr_sem);
780 if (!EXT2_I(inode)->i_file_acl)
782 bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
784 ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
785 "inode %ld: block %d read error", inode->i_ino,
786 EXT2_I(inode)->i_file_acl);
789 ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count)));
790 if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
791 HDR(bh)->h_blocks != cpu_to_le32(1)) {
792 ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
793 "inode %ld: bad block %d", inode->i_ino,
794 EXT2_I(inode)->i_file_acl);
797 ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, bh->b_blocknr);
799 if (HDR(bh)->h_refcount == cpu_to_le32(1)) {
801 mb_cache_entry_free(ce);
802 ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
806 HDR(bh)->h_refcount = cpu_to_le32(
807 le32_to_cpu(HDR(bh)->h_refcount) - 1);
809 mb_cache_entry_release(ce);
810 mark_buffer_dirty(bh);
812 sync_dirty_buffer(bh);
813 DLIMIT_FREE_BLOCK(inode->i_sb, inode->i_xid, 1);
814 DQUOT_FREE_BLOCK(inode, 1);
816 ea_bdebug(bh, "refcount now=%d", le32_to_cpu(HDR(bh)->h_refcount) - 1);
818 EXT2_I(inode)->i_file_acl = 0;
822 up_write(&EXT2_I(inode)->xattr_sem);
826 * ext2_xattr_put_super()
828 * This is called when a file system is unmounted.
831 ext2_xattr_put_super(struct super_block *sb)
833 mb_cache_shrink(ext2_xattr_cache, sb->s_bdev);
838 * ext2_xattr_cache_insert()
840 * Create a new entry in the extended attribute cache, and insert
841 * it unless such an entry is already in the cache.
843 * Returns 0, or a negative error number on failure.
846 ext2_xattr_cache_insert(struct buffer_head *bh)
848 __u32 hash = le32_to_cpu(HDR(bh)->h_hash);
849 struct mb_cache_entry *ce;
852 ce = mb_cache_entry_alloc(ext2_xattr_cache);
855 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
857 mb_cache_entry_free(ce);
858 if (error == -EBUSY) {
859 ea_bdebug(bh, "already in cache (%d cache entries)",
860 atomic_read(&ext2_xattr_cache->c_entry_count));
864 ea_bdebug(bh, "inserting [%x] (%d cache entries)", (int)hash,
865 atomic_read(&ext2_xattr_cache->c_entry_count));
866 mb_cache_entry_release(ce);
874 * Compare two extended attribute blocks for equality.
876 * Returns 0 if the blocks are equal, 1 if they differ, and
877 * a negative error number on errors.
880 ext2_xattr_cmp(struct ext2_xattr_header *header1,
881 struct ext2_xattr_header *header2)
883 struct ext2_xattr_entry *entry1, *entry2;
885 entry1 = ENTRY(header1+1);
886 entry2 = ENTRY(header2+1);
887 while (!IS_LAST_ENTRY(entry1)) {
888 if (IS_LAST_ENTRY(entry2))
890 if (entry1->e_hash != entry2->e_hash ||
891 entry1->e_name_index != entry2->e_name_index ||
892 entry1->e_name_len != entry2->e_name_len ||
893 entry1->e_value_size != entry2->e_value_size ||
894 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
896 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
898 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
899 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
900 le32_to_cpu(entry1->e_value_size)))
903 entry1 = EXT2_XATTR_NEXT(entry1);
904 entry2 = EXT2_XATTR_NEXT(entry2);
906 if (!IS_LAST_ENTRY(entry2))
912 * ext2_xattr_cache_find()
914 * Find an identical extended attribute block.
916 * Returns a locked buffer head to the block found, or NULL if such
917 * a block was not found or an error occurred.
919 static struct buffer_head *
920 ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
922 __u32 hash = le32_to_cpu(header->h_hash);
923 struct mb_cache_entry *ce;
926 return NULL; /* never share */
927 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
929 ce = mb_cache_entry_find_first(ext2_xattr_cache, 0,
930 inode->i_sb->s_bdev, hash);
932 struct buffer_head *bh;
935 if (PTR_ERR(ce) == -EAGAIN)
940 bh = sb_bread(inode->i_sb, ce->e_block);
942 ext2_error(inode->i_sb, "ext2_xattr_cache_find",
943 "inode %ld: block %ld read error",
944 inode->i_ino, (unsigned long) ce->e_block);
947 if (le32_to_cpu(HDR(bh)->h_refcount) >
948 EXT2_XATTR_REFCOUNT_MAX) {
949 ea_idebug(inode, "block %ld refcount %d>%d",
950 (unsigned long) ce->e_block,
951 le32_to_cpu(HDR(bh)->h_refcount),
952 EXT2_XATTR_REFCOUNT_MAX);
953 } else if (!ext2_xattr_cmp(header, HDR(bh))) {
954 ea_bdebug(bh, "b_count=%d",
955 atomic_read(&(bh->b_count)));
956 mb_cache_entry_release(ce);
962 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
967 #define NAME_HASH_SHIFT 5
968 #define VALUE_HASH_SHIFT 16
971 * ext2_xattr_hash_entry()
973 * Compute the hash of an extended attribute.
975 static inline void ext2_xattr_hash_entry(struct ext2_xattr_header *header,
976 struct ext2_xattr_entry *entry)
979 char *name = entry->e_name;
982 for (n=0; n < entry->e_name_len; n++) {
983 hash = (hash << NAME_HASH_SHIFT) ^
984 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
988 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
989 __le32 *value = (__le32 *)((char *)header +
990 le16_to_cpu(entry->e_value_offs));
991 for (n = (le32_to_cpu(entry->e_value_size) +
992 EXT2_XATTR_ROUND) >> EXT2_XATTR_PAD_BITS; n; n--) {
993 hash = (hash << VALUE_HASH_SHIFT) ^
994 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
995 le32_to_cpu(*value++);
998 entry->e_hash = cpu_to_le32(hash);
1001 #undef NAME_HASH_SHIFT
1002 #undef VALUE_HASH_SHIFT
1004 #define BLOCK_HASH_SHIFT 16
1007 * ext2_xattr_rehash()
1009 * Re-compute the extended attribute hash value after an entry has changed.
1011 static void ext2_xattr_rehash(struct ext2_xattr_header *header,
1012 struct ext2_xattr_entry *entry)
1014 struct ext2_xattr_entry *here;
1017 ext2_xattr_hash_entry(header, entry);
1018 here = ENTRY(header+1);
1019 while (!IS_LAST_ENTRY(here)) {
1020 if (!here->e_hash) {
1021 /* Block is not shared if an entry's hash value == 0 */
1025 hash = (hash << BLOCK_HASH_SHIFT) ^
1026 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1027 le32_to_cpu(here->e_hash);
1028 here = EXT2_XATTR_NEXT(here);
1030 header->h_hash = cpu_to_le32(hash);
1033 #undef BLOCK_HASH_SHIFT
1036 init_ext2_xattr(void)
1038 ext2_xattr_cache = mb_cache_create("ext2_xattr", NULL,
1039 sizeof(struct mb_cache_entry) +
1040 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1041 if (!ext2_xattr_cache)
1047 exit_ext2_xattr(void)
1049 mb_cache_destroy(ext2_xattr_cache);