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VFS: normal filesystems (and lustre): d_inode() annotations
[linux-2.6-block.git] / fs / ext3 / xattr.c
CommitLineData
1da177e4
LT		 1/*
2 * linux/fs/ext3/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext3 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>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16/*
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.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
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.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT3_I(inode)->i_file_acl is protected by EXT3_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
50 * by the buffer lock.
51 */
52
4613ad18 53#include "ext3.h"
1da177e4
LT		 54#include <linux/mbcache.h>
55#include <linux/quotaops.h>
1da177e4
LT		 56#include "xattr.h"
57#include "acl.h"
58
59#define BHDR(bh) ((struct ext3_xattr_header *)((bh)->b_data))
60#define ENTRY(ptr) ((struct ext3_xattr_entry *)(ptr))
61#define BFIRST(bh) ENTRY(BHDR(bh)+1)
62#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
63
64#define IHDR(inode, raw_inode) \
65 ((struct ext3_xattr_ibody_header *) \
66 ((void *)raw_inode + \
67 EXT3_GOOD_OLD_INODE_SIZE + \
68 EXT3_I(inode)->i_extra_isize))
69#define IFIRST(hdr) ((struct ext3_xattr_entry *)((hdr)+1))
70
71#ifdef EXT3_XATTR_DEBUG
72# define ea_idebug(inode, f...) do { \
eee194e7 73 printk(KERN_DEBUG "inode %s:%lu: ", \
1da177e4
LT		 74 inode->i_sb->s_id, inode->i_ino); \
75 printk(f); \
76 printk("\n"); \
77 } while (0)
78# define ea_bdebug(bh, f...) do { \
79 char b[BDEVNAME_SIZE]; \
80 printk(KERN_DEBUG "block %s:%lu: ", \
81 bdevname(bh->b_bdev, b), \
82 (unsigned long) bh->b_blocknr); \
83 printk(f); \
84 printk("\n"); \
85 } while (0)
86#else
87# define ea_idebug(f...)
88# define ea_bdebug(f...)
89#endif
90
91static void ext3_xattr_cache_insert(struct buffer_head *);
92static struct buffer_head *ext3_xattr_cache_find(struct inode *,
93 struct ext3_xattr_header *,
94 struct mb_cache_entry **);
95static void ext3_xattr_rehash(struct ext3_xattr_header *,
96 struct ext3_xattr_entry *);
431547b3 97static int ext3_xattr_list(struct dentry *dentry, char *buffer,
15633005 98 size_t buffer_size);
1da177e4
LT		 99
100static struct mb_cache *ext3_xattr_cache;
101
d1f21049 102static const struct xattr_handler *ext3_xattr_handler_map[] = {
1da177e4
LT		 103 [EXT3_XATTR_INDEX_USER] = &ext3_xattr_user_handler,
104#ifdef CONFIG_EXT3_FS_POSIX_ACL
64e178a7
CH		 105 [EXT3_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
106 [EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
1da177e4
LT		 107#endif
108 [EXT3_XATTR_INDEX_TRUSTED] = &ext3_xattr_trusted_handler,
109#ifdef CONFIG_EXT3_FS_SECURITY
110 [EXT3_XATTR_INDEX_SECURITY] = &ext3_xattr_security_handler,
111#endif
112};
113
d1f21049 114const struct xattr_handler *ext3_xattr_handlers[] = {
1da177e4
LT		 115 &ext3_xattr_user_handler,
116 &ext3_xattr_trusted_handler,
117#ifdef CONFIG_EXT3_FS_POSIX_ACL
64e178a7
CH		 118 &posix_acl_access_xattr_handler,
119 &posix_acl_default_xattr_handler,
1da177e4
LT		 120#endif
121#ifdef CONFIG_EXT3_FS_SECURITY
122 &ext3_xattr_security_handler,
123#endif
124 NULL
125};
126
d1f21049 127static inline const struct xattr_handler *
1da177e4
LT		 128ext3_xattr_handler(int name_index)
129{
d1f21049 130 const struct xattr_handler *handler = NULL;
1da177e4
LT		 131
132 if (name_index > 0 && name_index < ARRAY_SIZE(ext3_xattr_handler_map))
133 handler = ext3_xattr_handler_map[name_index];
134 return handler;
135}
136
137/*
138 * Inode operation listxattr()
139 *
2b0143b5 140 * d_inode(dentry)->i_mutex: don't care
1da177e4
LT		 141 */
142ssize_t
143ext3_listxattr(struct dentry *dentry, char *buffer, size_t size)
144{
431547b3 145 return ext3_xattr_list(dentry, buffer, size);
1da177e4
LT		 146}
147
148static int
149ext3_xattr_check_names(struct ext3_xattr_entry *entry, void *end)
150{
151 while (!IS_LAST_ENTRY(entry)) {
152 struct ext3_xattr_entry *next = EXT3_XATTR_NEXT(entry);
153 if ((void *)next >= end)
154 return -EIO;
155 entry = next;
156 }
157 return 0;
158}
159
160static inline int
161ext3_xattr_check_block(struct buffer_head *bh)
162{
163 int error;
164
165 if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
166 BHDR(bh)->h_blocks != cpu_to_le32(1))
167 return -EIO;
168 error = ext3_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
169 return error;
170}
171
172static inline int
173ext3_xattr_check_entry(struct ext3_xattr_entry *entry, size_t size)
174{
175 size_t value_size = le32_to_cpu(entry->e_value_size);
176
177 if (entry->e_value_block != 0 || value_size > size ||
178 le16_to_cpu(entry->e_value_offs) + value_size > size)
179 return -EIO;
180 return 0;
181}
182
183static int
184ext3_xattr_find_entry(struct ext3_xattr_entry **pentry, int name_index,
185 const char *name, size_t size, int sorted)
186{
187 struct ext3_xattr_entry *entry;
188 size_t name_len;
189 int cmp = 1;
190
191 if (name == NULL)
192 return -EINVAL;
193 name_len = strlen(name);
194 entry = *pentry;
195 for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
196 cmp = name_index - entry->e_name_index;
197 if (!cmp)
198 cmp = name_len - entry->e_name_len;
199 if (!cmp)
200 cmp = memcmp(name, entry->e_name, name_len);
201 if (cmp <= 0 && (sorted || cmp == 0))
202 break;
203 }
204 *pentry = entry;
205 if (!cmp && ext3_xattr_check_entry(entry, size))
206 return -EIO;
207 return cmp ? -ENODATA : 0;
208}
209
381be254 210static int
1da177e4
LT		 211ext3_xattr_block_get(struct inode *inode, int name_index, const char *name,
212 void *buffer, size_t buffer_size)
213{
214 struct buffer_head *bh = NULL;
215 struct ext3_xattr_entry *entry;
216 size_t size;
217 int error;
218
219 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
220 name_index, name, buffer, (long)buffer_size);
221
222 error = -ENODATA;
223 if (!EXT3_I(inode)->i_file_acl)
224 goto cleanup;
1c2bf374 225 ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
1da177e4
LT		 226 bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
227 if (!bh)
228 goto cleanup;
229 ea_bdebug(bh, "b_count=%d, refcount=%d",
230 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
231 if (ext3_xattr_check_block(bh)) {
e05b6b52 232bad_block: ext3_error(inode->i_sb, __func__,
eee194e7 233 "inode %lu: bad block "E3FSBLK, inode->i_ino,
1da177e4
LT		 234 EXT3_I(inode)->i_file_acl);
235 error = -EIO;
236 goto cleanup;
237 }
238 ext3_xattr_cache_insert(bh);
239 entry = BFIRST(bh);
240 error = ext3_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
241 if (error == -EIO)
242 goto bad_block;
243 if (error)
244 goto cleanup;
245 size = le32_to_cpu(entry->e_value_size);
246 if (buffer) {
247 error = -ERANGE;
248 if (size > buffer_size)
249 goto cleanup;
250 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
251 size);
252 }
253 error = size;
254
255cleanup:
256 brelse(bh);
257 return error;
258}
259
260static int
261ext3_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
262 void *buffer, size_t buffer_size)
263{
264 struct ext3_xattr_ibody_header *header;
265 struct ext3_xattr_entry *entry;
266 struct ext3_inode *raw_inode;
267 struct ext3_iloc iloc;
268 size_t size;
269 void *end;
270 int error;
271
9df93939 272 if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
1da177e4
LT		 273 return -ENODATA;
274 error = ext3_get_inode_loc(inode, &iloc);
275 if (error)
276 return error;
277 raw_inode = ext3_raw_inode(&iloc);
278 header = IHDR(inode, raw_inode);
279 entry = IFIRST(header);
280 end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
281 error = ext3_xattr_check_names(entry, end);
282 if (error)
283 goto cleanup;
284 error = ext3_xattr_find_entry(&entry, name_index, name,
285 end - (void *)entry, 0);
286 if (error)
287 goto cleanup;
288 size = le32_to_cpu(entry->e_value_size);
289 if (buffer) {
290 error = -ERANGE;
291 if (size > buffer_size)
292 goto cleanup;
293 memcpy(buffer, (void *)IFIRST(header) +
294 le16_to_cpu(entry->e_value_offs), size);
295 }
296 error = size;
297
298cleanup:
299 brelse(iloc.bh);
300 return error;
301}
302
303/*
304 * ext3_xattr_get()
305 *
306 * Copy an extended attribute into the buffer
307 * provided, or compute the buffer size required.
308 * Buffer is NULL to compute the size of the buffer required.
309 *
310 * Returns a negative error number on failure, or the number of bytes
311 * used / required on success.
312 */
313int
314ext3_xattr_get(struct inode *inode, int name_index, const char *name,
315 void *buffer, size_t buffer_size)
316{
317 int error;
318
319 down_read(&EXT3_I(inode)->xattr_sem);
320 error = ext3_xattr_ibody_get(inode, name_index, name, buffer,
321 buffer_size);
322 if (error == -ENODATA)
323 error = ext3_xattr_block_get(inode, name_index, name, buffer,
324 buffer_size);
325 up_read(&EXT3_I(inode)->xattr_sem);
326 return error;
327}
328
329static int
431547b3 330ext3_xattr_list_entries(struct dentry *dentry, struct ext3_xattr_entry *entry,
1da177e4
LT		 331 char *buffer, size_t buffer_size)
332{
333 size_t rest = buffer_size;
334
335 for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
d1f21049 336 const struct xattr_handler *handler =
1da177e4
LT		 337 ext3_xattr_handler(entry->e_name_index);
338
339 if (handler) {
431547b3 340 size_t size = handler->list(dentry, buffer, rest,
1da177e4 341 entry->e_name,
431547b3
CH		 342 entry->e_name_len,
343 handler->flags);
1da177e4
LT		 344 if (buffer) {
345 if (size > rest)
346 return -ERANGE;
347 buffer += size;
348 }
349 rest -= size;
350 }
351 }
352 return buffer_size - rest;
353}
354
381be254 355static int
431547b3 356ext3_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
1da177e4 357{
2b0143b5 358 struct inode *inode = d_inode(dentry);
1da177e4
LT		 359 struct buffer_head *bh = NULL;
360 int error;
361
362 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
363 buffer, (long)buffer_size);
364
365 error = 0;
366 if (!EXT3_I(inode)->i_file_acl)
367 goto cleanup;
1c2bf374 368 ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
1da177e4
LT		 369 bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
370 error = -EIO;
371 if (!bh)
372 goto cleanup;
373 ea_bdebug(bh, "b_count=%d, refcount=%d",
374 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
375 if (ext3_xattr_check_block(bh)) {
e05b6b52 376 ext3_error(inode->i_sb, __func__,
eee194e7 377 "inode %lu: bad block "E3FSBLK, inode->i_ino,
1da177e4
LT		 378 EXT3_I(inode)->i_file_acl);
379 error = -EIO;
380 goto cleanup;
381 }
382 ext3_xattr_cache_insert(bh);
431547b3 383 error = ext3_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
1da177e4
LT		 384
385cleanup:
386 brelse(bh);
387
388 return error;
389}
390
391static int
431547b3 392ext3_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
1da177e4 393{
2b0143b5 394 struct inode *inode = d_inode(dentry);
1da177e4
LT		 395 struct ext3_xattr_ibody_header *header;
396 struct ext3_inode *raw_inode;
397 struct ext3_iloc iloc;
398 void *end;
399 int error;
400
9df93939 401 if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
1da177e4
LT		 402 return 0;
403 error = ext3_get_inode_loc(inode, &iloc);
404 if (error)
405 return error;
406 raw_inode = ext3_raw_inode(&iloc);
407 header = IHDR(inode, raw_inode);
408 end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
409 error = ext3_xattr_check_names(IFIRST(header), end);
410 if (error)
411 goto cleanup;
431547b3 412 error = ext3_xattr_list_entries(dentry, IFIRST(header),
1da177e4
LT		 413 buffer, buffer_size);
414
415cleanup:
416 brelse(iloc.bh);
417 return error;
418}
419
420/*
421 * ext3_xattr_list()
422 *
423 * Copy a list of attribute names into the buffer
424 * provided, or compute the buffer size required.
425 * Buffer is NULL to compute the size of the buffer required.
426 *
427 * Returns a negative error number on failure, or the number of bytes
428 * used / required on success.
429 */
15633005 430static int
431547b3 431ext3_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
1da177e4
LT		 432{
433 int i_error, b_error;
434
2b0143b5 435 down_read(&EXT3_I(d_inode(dentry))->xattr_sem);
431547b3 436 i_error = ext3_xattr_ibody_list(dentry, buffer, buffer_size);
1da177e4
LT		 437 if (i_error < 0) {
438 b_error = 0;
439 } else {
440 if (buffer) {
441 buffer += i_error;
442 buffer_size -= i_error;
443 }
431547b3 444 b_error = ext3_xattr_block_list(dentry, buffer, buffer_size);
1da177e4
LT		 445 if (b_error < 0)
446 i_error = 0;
447 }
2b0143b5 448 up_read(&EXT3_I(d_inode(dentry))->xattr_sem);
1da177e4
LT		 449 return i_error + b_error;
450}
451
452/*
453 * If the EXT3_FEATURE_COMPAT_EXT_ATTR feature of this file system is
454 * not set, set it.
455 */
456static void ext3_xattr_update_super_block(handle_t *handle,
457 struct super_block *sb)
458{
459 if (EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR))
460 return;
461
1da177e4 462 if (ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh) == 0) {
ed2908f3 463 EXT3_SET_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR);
1da177e4
LT		 464 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
465 }
1da177e4
LT		 466}
467
468/*
469 * Release the xattr block BH: If the reference count is > 1, decrement
470 * it; otherwise free the block.
471 */
472static void
473ext3_xattr_release_block(handle_t *handle, struct inode *inode,
474 struct buffer_head *bh)
475{
476 struct mb_cache_entry *ce = NULL;
8a2bfdcb 477 int error = 0;
1da177e4
LT		 478
479 ce = mb_cache_entry_get(ext3_xattr_cache, bh->b_bdev, bh->b_blocknr);
8a2bfdcb
MC		 480 error = ext3_journal_get_write_access(handle, bh);
481 if (error)
482 goto out;
483
484 lock_buffer(bh);
485
1da177e4
LT		 486 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
487 ea_bdebug(bh, "refcount now=0; freeing");
488 if (ce)
489 mb_cache_entry_free(ce);
490 ext3_free_blocks(handle, inode, bh->b_blocknr, 1);
491 get_bh(bh);
492 ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
493 } else {
50e8a289 494 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
8a2bfdcb 495 error = ext3_journal_dirty_metadata(handle, bh);
105fd108
AM		 496 if (IS_SYNC(inode))
497 handle->h_sync = 1;
5dd4056d 498 dquot_free_block(inode, 1);
8a2bfdcb
MC		 499 ea_bdebug(bh, "refcount now=%d; releasing",
500 le32_to_cpu(BHDR(bh)->h_refcount));
1da177e4
LT		 501 if (ce)
502 mb_cache_entry_release(ce);
503 }
8a2bfdcb
MC		 504 unlock_buffer(bh);
505out:
506 ext3_std_error(inode->i_sb, error);
507 return;
1da177e4
LT		 508}
509
510struct ext3_xattr_info {
511 int name_index;
512 const char *name;
513 const void *value;
514 size_t value_len;
515};
516
517struct ext3_xattr_search {
518 struct ext3_xattr_entry *first;
519 void *base;
520 void *end;
521 struct ext3_xattr_entry *here;
522 int not_found;
523};
524
525static int
526ext3_xattr_set_entry(struct ext3_xattr_info *i, struct ext3_xattr_search *s)
527{
528 struct ext3_xattr_entry *last;
529 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
530
531 /* Compute min_offs and last. */
532 last = s->first;
533 for (; !IS_LAST_ENTRY(last); last = EXT3_XATTR_NEXT(last)) {
534 if (!last->e_value_block && last->e_value_size) {
535 size_t offs = le16_to_cpu(last->e_value_offs);
536 if (offs < min_offs)
537 min_offs = offs;
538 }
539 }
540 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
541 if (!s->not_found) {
542 if (!s->here->e_value_block && s->here->e_value_size) {
543 size_t size = le32_to_cpu(s->here->e_value_size);
544 free += EXT3_XATTR_SIZE(size);
545 }
546 free += EXT3_XATTR_LEN(name_len);
547 }
548 if (i->value) {
549 if (free < EXT3_XATTR_SIZE(i->value_len) ||
550 free < EXT3_XATTR_LEN(name_len) +
551 EXT3_XATTR_SIZE(i->value_len))
552 return -ENOSPC;
553 }
554
555 if (i->value && s->not_found) {
556 /* Insert the new name. */
557 size_t size = EXT3_XATTR_LEN(name_len);
558 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
559 memmove((void *)s->here + size, s->here, rest);
560 memset(s->here, 0, size);
561 s->here->e_name_index = i->name_index;
562 s->here->e_name_len = name_len;
563 memcpy(s->here->e_name, i->name, name_len);
564 } else {
565 if (!s->here->e_value_block && s->here->e_value_size) {
566 void *first_val = s->base + min_offs;
567 size_t offs = le16_to_cpu(s->here->e_value_offs);
568 void *val = s->base + offs;
569 size_t size = EXT3_XATTR_SIZE(
570 le32_to_cpu(s->here->e_value_size));
571
572 if (i->value && size == EXT3_XATTR_SIZE(i->value_len)) {
573 /* The old and the new value have the same
574 size. Just replace. */
575 s->here->e_value_size =
576 cpu_to_le32(i->value_len);
577 memset(val + size - EXT3_XATTR_PAD, 0,
578 EXT3_XATTR_PAD); /* Clear pad bytes. */
579 memcpy(val, i->value, i->value_len);
580 return 0;
581 }
582
583 /* Remove the old value. */
584 memmove(first_val + size, first_val, val - first_val);
585 memset(first_val, 0, size);
586 s->here->e_value_size = 0;
587 s->here->e_value_offs = 0;
588 min_offs += size;
589
590 /* Adjust all value offsets. */
591 last = s->first;
592 while (!IS_LAST_ENTRY(last)) {
593 size_t o = le16_to_cpu(last->e_value_offs);
594 if (!last->e_value_block &&
595 last->e_value_size && o < offs)
596 last->e_value_offs =
597 cpu_to_le16(o + size);
598 last = EXT3_XATTR_NEXT(last);
599 }
600 }
601 if (!i->value) {
602 /* Remove the old name. */
603 size_t size = EXT3_XATTR_LEN(name_len);
604 last = ENTRY((void *)last - size);
605 memmove(s->here, (void *)s->here + size,
606 (void *)last - (void *)s->here + sizeof(__u32));
607 memset(last, 0, size);
608 }
609 }
610
611 if (i->value) {
612 /* Insert the new value. */
613 s->here->e_value_size = cpu_to_le32(i->value_len);
614 if (i->value_len) {
615 size_t size = EXT3_XATTR_SIZE(i->value_len);
616 void *val = s->base + min_offs - size;
617 s->here->e_value_offs = cpu_to_le16(min_offs - size);
618 memset(val + size - EXT3_XATTR_PAD, 0,
619 EXT3_XATTR_PAD); /* Clear the pad bytes. */
620 memcpy(val, i->value, i->value_len);
621 }
622 }
623 return 0;
624}
625
626struct ext3_xattr_block_find {
627 struct ext3_xattr_search s;
628 struct buffer_head *bh;
629};
630
381be254 631static int
1da177e4
LT		 632ext3_xattr_block_find(struct inode *inode, struct ext3_xattr_info *i,
633 struct ext3_xattr_block_find *bs)
634{
635 struct super_block *sb = inode->i_sb;
636 int error;
637
638 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
639 i->name_index, i->name, i->value, (long)i->value_len);
640
641 if (EXT3_I(inode)->i_file_acl) {
642 /* The inode already has an extended attribute block. */
643 bs->bh = sb_bread(sb, EXT3_I(inode)->i_file_acl);
644 error = -EIO;
645 if (!bs->bh)
646 goto cleanup;
647 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
648 atomic_read(&(bs->bh->b_count)),
649 le32_to_cpu(BHDR(bs->bh)->h_refcount));
650 if (ext3_xattr_check_block(bs->bh)) {
e05b6b52 651 ext3_error(sb, __func__,
eee194e7 652 "inode %lu: bad block "E3FSBLK, inode->i_ino,
1da177e4
LT		 653 EXT3_I(inode)->i_file_acl);
654 error = -EIO;
655 goto cleanup;
656 }
657 /* Find the named attribute. */
658 bs->s.base = BHDR(bs->bh);
659 bs->s.first = BFIRST(bs->bh);
660 bs->s.end = bs->bh->b_data + bs->bh->b_size;
661 bs->s.here = bs->s.first;
662 error = ext3_xattr_find_entry(&bs->s.here, i->name_index,
663 i->name, bs->bh->b_size, 1);
664 if (error && error != -ENODATA)
665 goto cleanup;
666 bs->s.not_found = error;
667 }
668 error = 0;
669
670cleanup:
671 return error;
672}
673
674static int
675ext3_xattr_block_set(handle_t *handle, struct inode *inode,
676 struct ext3_xattr_info *i,
677 struct ext3_xattr_block_find *bs)
678{
679 struct super_block *sb = inode->i_sb;
680 struct buffer_head *new_bh = NULL;
681 struct ext3_xattr_search *s = &bs->s;
682 struct mb_cache_entry *ce = NULL;
8a2bfdcb 683 int error = 0;
1da177e4
LT		 684
685#define header(x) ((struct ext3_xattr_header *)(x))
686
687 if (i->value && i->value_len > sb->s_blocksize)
688 return -ENOSPC;
689 if (s->base) {
690 ce = mb_cache_entry_get(ext3_xattr_cache, bs->bh->b_bdev,
691 bs->bh->b_blocknr);
8a2bfdcb
MC		 692 error = ext3_journal_get_write_access(handle, bs->bh);
693 if (error)
694 goto cleanup;
695 lock_buffer(bs->bh);
696
1da177e4
LT		 697 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
698 if (ce) {
699 mb_cache_entry_free(ce);
700 ce = NULL;
701 }
702 ea_bdebug(bs->bh, "modifying in-place");
1da177e4
LT		 703 error = ext3_xattr_set_entry(i, s);
704 if (!error) {
705 if (!IS_LAST_ENTRY(s->first))
706 ext3_xattr_rehash(header(s->base),
707 s->here);
708 ext3_xattr_cache_insert(bs->bh);
709 }
710 unlock_buffer(bs->bh);
711 if (error == -EIO)
712 goto bad_block;
713 if (!error)
714 error = ext3_journal_dirty_metadata(handle,
715 bs->bh);
716 if (error)
717 goto cleanup;
718 goto inserted;
719 } else {
720 int offset = (char *)s->here - bs->bh->b_data;
721
8a2bfdcb
MC		 722 unlock_buffer(bs->bh);
723 journal_release_buffer(handle, bs->bh);
724
1da177e4
LT		 725 if (ce) {
726 mb_cache_entry_release(ce);
727 ce = NULL;
728 }
729 ea_bdebug(bs->bh, "cloning");
c587f0c0 730 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1da177e4
LT		 731 error = -ENOMEM;
732 if (s->base == NULL)
733 goto cleanup;
734 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
735 s->first = ENTRY(header(s->base)+1);
736 header(s->base)->h_refcount = cpu_to_le32(1);
737 s->here = ENTRY(s->base + offset);
738 s->end = s->base + bs->bh->b_size;
739 }
740 } else {
741 /* Allocate a buffer where we construct the new block. */
c587f0c0 742 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1da177e4
LT		 743 /* assert(header == s->base) */
744 error = -ENOMEM;
745 if (s->base == NULL)
746 goto cleanup;
1da177e4
LT		 747 header(s->base)->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
748 header(s->base)->h_blocks = cpu_to_le32(1);
749 header(s->base)->h_refcount = cpu_to_le32(1);
750 s->first = ENTRY(header(s->base)+1);
751 s->here = ENTRY(header(s->base)+1);
752 s->end = s->base + sb->s_blocksize;
753 }
754
755 error = ext3_xattr_set_entry(i, s);
756 if (error == -EIO)
757 goto bad_block;
758 if (error)
759 goto cleanup;
760 if (!IS_LAST_ENTRY(s->first))
761 ext3_xattr_rehash(header(s->base), s->here);
762
763inserted:
764 if (!IS_LAST_ENTRY(s->first)) {
765 new_bh = ext3_xattr_cache_find(inode, header(s->base), &ce);
766 if (new_bh) {
767 /* We found an identical block in the cache. */
768 if (new_bh == bs->bh)
769 ea_bdebug(new_bh, "keeping");
770 else {
771 /* The old block is released after updating
772 the inode. */
5dd4056d
CH		 773 error = dquot_alloc_block(inode, 1);
774 if (error)
1da177e4
LT		 775 goto cleanup;
776 error = ext3_journal_get_write_access(handle,
777 new_bh);
778 if (error)
779 goto cleanup_dquot;
780 lock_buffer(new_bh);
50e8a289 781 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
1da177e4
LT		 782 ea_bdebug(new_bh, "reusing; refcount now=%d",
783 le32_to_cpu(BHDR(new_bh)->h_refcount));
784 unlock_buffer(new_bh);
785 error = ext3_journal_dirty_metadata(handle,
786 new_bh);
787 if (error)
788 goto cleanup_dquot;
789 }
790 mb_cache_entry_release(ce);
791 ce = NULL;
792 } else if (bs->bh && s->base == bs->bh->b_data) {
793 /* We were modifying this block in-place. */
794 ea_bdebug(bs->bh, "keeping this block");
795 new_bh = bs->bh;
796 get_bh(new_bh);
797 } else {
798 /* We need to allocate a new block */
1eaafeae
AM		 799 ext3_fsblk_t goal = ext3_group_first_block_no(sb,
800 EXT3_I(inode)->i_block_group);
ad95c5e9
JK		 801 ext3_fsblk_t block;
802
803 /*
804 * Protect us agaist concurrent allocations to the
805 * same inode from ext3_..._writepage(). Reservation
806 * code does not expect racing allocations.
807 */
808 mutex_lock(&EXT3_I(inode)->truncate_mutex);
809 block = ext3_new_block(handle, inode, goal, &error);
810 mutex_unlock(&EXT3_I(inode)->truncate_mutex);
1da177e4
LT		 811 if (error)
812 goto cleanup;
813 ea_idebug(inode, "creating block %d", block);
814
815 new_bh = sb_getblk(sb, block);
1b7d76e9 816 if (unlikely(!new_bh)) {
1da177e4
LT		 817getblk_failed:
818 ext3_free_blocks(handle, inode, block, 1);
c04e88e2 819 error = -ENOMEM;
1da177e4
LT		 820 goto cleanup;
821 }
822 lock_buffer(new_bh);
823 error = ext3_journal_get_create_access(handle, new_bh);
824 if (error) {
825 unlock_buffer(new_bh);
826 goto getblk_failed;
827 }
828 memcpy(new_bh->b_data, s->base, new_bh->b_size);
829 set_buffer_uptodate(new_bh);
830 unlock_buffer(new_bh);
831 ext3_xattr_cache_insert(new_bh);
832 error = ext3_journal_dirty_metadata(handle, new_bh);
833 if (error)
834 goto cleanup;
835 }
836 }
837
838 /* Update the inode. */
839 EXT3_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
840
841 /* Drop the previous xattr block. */
842 if (bs->bh && bs->bh != new_bh)
843 ext3_xattr_release_block(handle, inode, bs->bh);
844 error = 0;
845
846cleanup:
847 if (ce)
848 mb_cache_entry_release(ce);
849 brelse(new_bh);
850 if (!(bs->bh && s->base == bs->bh->b_data))
851 kfree(s->base);
852
853 return error;
854
855cleanup_dquot:
5dd4056d 856 dquot_free_block(inode, 1);
1da177e4
LT		 857 goto cleanup;
858
859bad_block:
e05b6b52 860 ext3_error(inode->i_sb, __func__,
eee194e7 861 "inode %lu: bad block "E3FSBLK, inode->i_ino,
1da177e4
LT		 862 EXT3_I(inode)->i_file_acl);
863 goto cleanup;
864
865#undef header
866}
867
868struct ext3_xattr_ibody_find {
869 struct ext3_xattr_search s;
870 struct ext3_iloc iloc;
871};
872
381be254 873static int
1da177e4
LT		 874ext3_xattr_ibody_find(struct inode *inode, struct ext3_xattr_info *i,
875 struct ext3_xattr_ibody_find *is)
876{
877 struct ext3_xattr_ibody_header *header;
878 struct ext3_inode *raw_inode;
879 int error;
880
881 if (EXT3_I(inode)->i_extra_isize == 0)
882 return 0;
883 raw_inode = ext3_raw_inode(&is->iloc);
884 header = IHDR(inode, raw_inode);
885 is->s.base = is->s.first = IFIRST(header);
886 is->s.here = is->s.first;
887 is->s.end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
9df93939 888 if (ext3_test_inode_state(inode, EXT3_STATE_XATTR)) {
1da177e4
LT		 889 error = ext3_xattr_check_names(IFIRST(header), is->s.end);
890 if (error)
891 return error;
892 /* Find the named attribute. */
893 error = ext3_xattr_find_entry(&is->s.here, i->name_index,
894 i->name, is->s.end -
895 (void *)is->s.base, 0);
896 if (error && error != -ENODATA)
897 return error;
898 is->s.not_found = error;
899 }
900 return 0;
901}
902
903static int
904ext3_xattr_ibody_set(handle_t *handle, struct inode *inode,
905 struct ext3_xattr_info *i,
906 struct ext3_xattr_ibody_find *is)
907{
908 struct ext3_xattr_ibody_header *header;
909 struct ext3_xattr_search *s = &is->s;
910 int error;
911
912 if (EXT3_I(inode)->i_extra_isize == 0)
913 return -ENOSPC;
914 error = ext3_xattr_set_entry(i, s);
915 if (error)
916 return error;
917 header = IHDR(inode, ext3_raw_inode(&is->iloc));
918 if (!IS_LAST_ENTRY(s->first)) {
919 header->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
9df93939 920 ext3_set_inode_state(inode, EXT3_STATE_XATTR);
1da177e4
LT		 921 } else {
922 header->h_magic = cpu_to_le32(0);
9df93939 923 ext3_clear_inode_state(inode, EXT3_STATE_XATTR);
1da177e4
LT		 924 }
925 return 0;
926}
927
928/*
929 * ext3_xattr_set_handle()
930 *
6e9510b0 931 * Create, replace or remove an extended attribute for this inode. Value
1da177e4
LT		 932 * is NULL to remove an existing extended attribute, and non-NULL to
933 * either replace an existing extended attribute, or create a new extended
934 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
935 * specify that an extended attribute must exist and must not exist
936 * previous to the call, respectively.
937 *
938 * Returns 0, or a negative error number on failure.
939 */
940int
941ext3_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
942 const char *name, const void *value, size_t value_len,
943 int flags)
944{
945 struct ext3_xattr_info i = {
946 .name_index = name_index,
947 .name = name,
948 .value = value,
949 .value_len = value_len,
950
951 };
952 struct ext3_xattr_ibody_find is = {
953 .s = { .not_found = -ENODATA, },
954 };
955 struct ext3_xattr_block_find bs = {
956 .s = { .not_found = -ENODATA, },
957 };
958 int error;
959
1da177e4
LT		 960 if (!name)
961 return -EINVAL;
962 if (strlen(name) > 255)
963 return -ERANGE;
964 down_write(&EXT3_I(inode)->xattr_sem);
965 error = ext3_get_inode_loc(inode, &is.iloc);
966 if (error)
967 goto cleanup;
968
d965736b
ES		 969 error = ext3_journal_get_write_access(handle, is.iloc.bh);
970 if (error)
971 goto cleanup;
972
9df93939 973 if (ext3_test_inode_state(inode, EXT3_STATE_NEW)) {
1da177e4
LT		 974 struct ext3_inode *raw_inode = ext3_raw_inode(&is.iloc);
975 memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
9df93939 976 ext3_clear_inode_state(inode, EXT3_STATE_NEW);
1da177e4
LT		 977 }
978
979 error = ext3_xattr_ibody_find(inode, &i, &is);
980 if (error)
981 goto cleanup;
982 if (is.s.not_found)
983 error = ext3_xattr_block_find(inode, &i, &bs);
984 if (error)
985 goto cleanup;
986 if (is.s.not_found && bs.s.not_found) {
987 error = -ENODATA;
988 if (flags & XATTR_REPLACE)
989 goto cleanup;
990 error = 0;
991 if (!value)
992 goto cleanup;
993 } else {
994 error = -EEXIST;
995 if (flags & XATTR_CREATE)
996 goto cleanup;
997 }
1da177e4
LT		 998 if (!value) {
999 if (!is.s.not_found)
1000 error = ext3_xattr_ibody_set(handle, inode, &i, &is);
1001 else if (!bs.s.not_found)
1002 error = ext3_xattr_block_set(handle, inode, &i, &bs);
1003 } else {
1004 error = ext3_xattr_ibody_set(handle, inode, &i, &is);
1005 if (!error && !bs.s.not_found) {
1006 i.value = NULL;
1007 error = ext3_xattr_block_set(handle, inode, &i, &bs);
1008 } else if (error == -ENOSPC) {
7e01c8e5
TY		 1009 if (EXT3_I(inode)->i_file_acl && !bs.s.base) {
1010 error = ext3_xattr_block_find(inode, &i, &bs);
1011 if (error)
1012 goto cleanup;
1013 }
1da177e4
LT		 1014 error = ext3_xattr_block_set(handle, inode, &i, &bs);
1015 if (error)
1016 goto cleanup;
1017 if (!is.s.not_found) {
1018 i.value = NULL;
1019 error = ext3_xattr_ibody_set(handle, inode, &i,
1020 &is);
1021 }
1022 }
1023 }
1024 if (!error) {
1025 ext3_xattr_update_super_block(handle, inode->i_sb);
1026 inode->i_ctime = CURRENT_TIME_SEC;
1027 error = ext3_mark_iloc_dirty(handle, inode, &is.iloc);
1028 /*
1029 * The bh is consumed by ext3_mark_iloc_dirty, even with
1030 * error != 0.
1031 */
1032 is.iloc.bh = NULL;
1033 if (IS_SYNC(inode))
1034 handle->h_sync = 1;
1035 }
1036
1037cleanup:
1038 brelse(is.iloc.bh);
1039 brelse(bs.bh);
1040 up_write(&EXT3_I(inode)->xattr_sem);
1041 return error;
1042}
1043
1044/*
1045 * ext3_xattr_set()
1046 *
1047 * Like ext3_xattr_set_handle, but start from an inode. This extended
1048 * attribute modification is a filesystem transaction by itself.
1049 *
1050 * Returns 0, or a negative error number on failure.
1051 */
1052int
1053ext3_xattr_set(struct inode *inode, int name_index, const char *name,
1054 const void *value, size_t value_len, int flags)
1055{
1056 handle_t *handle;
1057 int error, retries = 0;
1058
1059retry:
1f54587b 1060 handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
1da177e4
LT		 1061 if (IS_ERR(handle)) {
1062 error = PTR_ERR(handle);
1063 } else {
1064 int error2;
1065
1066 error = ext3_xattr_set_handle(handle, inode, name_index, name,
1067 value, value_len, flags);
1068 error2 = ext3_journal_stop(handle);
1069 if (error == -ENOSPC &&
1070 ext3_should_retry_alloc(inode->i_sb, &retries))
1071 goto retry;
1072 if (error == 0)
1073 error = error2;
1074 }
1075
1076 return error;
1077}
1078
1079/*
1080 * ext3_xattr_delete_inode()
1081 *
1082 * Free extended attribute resources associated with this inode. This
1083 * is called immediately before an inode is freed. We have exclusive
1084 * access to the inode.
1085 */
1086void
1087ext3_xattr_delete_inode(handle_t *handle, struct inode *inode)
1088{
1089 struct buffer_head *bh = NULL;
1090
1091 if (!EXT3_I(inode)->i_file_acl)
1092 goto cleanup;
1093 bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
1094 if (!bh) {
e05b6b52 1095 ext3_error(inode->i_sb, __func__,
eee194e7 1096 "inode %lu: block "E3FSBLK" read error", inode->i_ino,
1da177e4
LT		 1097 EXT3_I(inode)->i_file_acl);
1098 goto cleanup;
1099 }
1100 if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
1101 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
e05b6b52 1102 ext3_error(inode->i_sb, __func__,
eee194e7 1103 "inode %lu: bad block "E3FSBLK, inode->i_ino,
1da177e4
LT		 1104 EXT3_I(inode)->i_file_acl);
1105 goto cleanup;
1106 }
1107 ext3_xattr_release_block(handle, inode, bh);
1108 EXT3_I(inode)->i_file_acl = 0;
1109
1110cleanup:
1111 brelse(bh);
1112}
1113
1114/*
1115 * ext3_xattr_put_super()
1116 *
1117 * This is called when a file system is unmounted.
1118 */
1119void
1120ext3_xattr_put_super(struct super_block *sb)
1121{
8c52ab42 1122 mb_cache_shrink(sb->s_bdev);
1da177e4
LT		 1123}
1124
1125/*
1126 * ext3_xattr_cache_insert()
1127 *
1128 * Create a new entry in the extended attribute cache, and insert
1129 * it unless such an entry is already in the cache.
1130 *
1131 * Returns 0, or a negative error number on failure.
1132 */
1133static void
1134ext3_xattr_cache_insert(struct buffer_head *bh)
1135{
1136 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1137 struct mb_cache_entry *ce;
1138 int error;
1139
335e92e8 1140 ce = mb_cache_entry_alloc(ext3_xattr_cache, GFP_NOFS);
1da177e4
LT		 1141 if (!ce) {
1142 ea_bdebug(bh, "out of memory");
1143 return;
1144 }
2aec7c52 1145 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1da177e4
LT		 1146 if (error) {
1147 mb_cache_entry_free(ce);
1148 if (error == -EBUSY) {
1149 ea_bdebug(bh, "already in cache");
1150 error = 0;
1151 }
1152 } else {
1153 ea_bdebug(bh, "inserting [%x]", (int)hash);
1154 mb_cache_entry_release(ce);
1155 }
1156}
1157
1158/*
1159 * ext3_xattr_cmp()
1160 *
1161 * Compare two extended attribute blocks for equality.
1162 *
1163 * Returns 0 if the blocks are equal, 1 if they differ, and
1164 * a negative error number on errors.
1165 */
1166static int
1167ext3_xattr_cmp(struct ext3_xattr_header *header1,
1168 struct ext3_xattr_header *header2)
1169{
1170 struct ext3_xattr_entry *entry1, *entry2;
1171
1172 entry1 = ENTRY(header1+1);
1173 entry2 = ENTRY(header2+1);
1174 while (!IS_LAST_ENTRY(entry1)) {
1175 if (IS_LAST_ENTRY(entry2))
1176 return 1;
1177 if (entry1->e_hash != entry2->e_hash ||
1178 entry1->e_name_index != entry2->e_name_index ||
1179 entry1->e_name_len != entry2->e_name_len ||
1180 entry1->e_value_size != entry2->e_value_size ||
1181 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1182 return 1;
1183 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1184 return -EIO;
1185 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1186 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1187 le32_to_cpu(entry1->e_value_size)))
1188 return 1;
1189
1190 entry1 = EXT3_XATTR_NEXT(entry1);
1191 entry2 = EXT3_XATTR_NEXT(entry2);
1192 }
1193 if (!IS_LAST_ENTRY(entry2))
1194 return 1;
1195 return 0;
1196}
1197
1198/*
1199 * ext3_xattr_cache_find()
1200 *
1201 * Find an identical extended attribute block.
1202 *
1203 * Returns a pointer to the block found, or NULL if such a block was
1204 * not found or an error occurred.
1205 */
1206static struct buffer_head *
1207ext3_xattr_cache_find(struct inode *inode, struct ext3_xattr_header *header,
1208 struct mb_cache_entry **pce)
1209{
1210 __u32 hash = le32_to_cpu(header->h_hash);
1211 struct mb_cache_entry *ce;
1212
1213 if (!header->h_hash)
1214 return NULL; /* never share */
1215 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1216again:
2aec7c52
AG		 1217 ce = mb_cache_entry_find_first(ext3_xattr_cache, inode->i_sb->s_bdev,
1218 hash);
1da177e4
LT		 1219 while (ce) {
1220 struct buffer_head *bh;
1221
1222 if (IS_ERR(ce)) {
1223 if (PTR_ERR(ce) == -EAGAIN)
1224 goto again;
1225 break;
1226 }
1227 bh = sb_bread(inode->i_sb, ce->e_block);
1228 if (!bh) {
e05b6b52 1229 ext3_error(inode->i_sb, __func__,
eee194e7 1230 "inode %lu: block %lu read error",
1da177e4
LT		 1231 inode->i_ino, (unsigned long) ce->e_block);
1232 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1233 EXT3_XATTR_REFCOUNT_MAX) {
1c2bf374 1234 ea_idebug(inode, "block %lu refcount %d>=%d",
1da177e4
LT		 1235 (unsigned long) ce->e_block,
1236 le32_to_cpu(BHDR(bh)->h_refcount),
1237 EXT3_XATTR_REFCOUNT_MAX);
1238 } else if (ext3_xattr_cmp(header, BHDR(bh)) == 0) {
1239 *pce = ce;
1240 return bh;
1241 }
1242 brelse(bh);
2aec7c52 1243 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1da177e4
LT		 1244 }
1245 return NULL;
1246}
1247
1248#define NAME_HASH_SHIFT 5
1249#define VALUE_HASH_SHIFT 16
1250
1251/*
1252 * ext3_xattr_hash_entry()
1253 *
1254 * Compute the hash of an extended attribute.
1255 */
1256static inline void ext3_xattr_hash_entry(struct ext3_xattr_header *header,
1257 struct ext3_xattr_entry *entry)
1258{
1259 __u32 hash = 0;
1260 char *name = entry->e_name;
1261 int n;
1262
1263 for (n=0; n < entry->e_name_len; n++) {
1264 hash = (hash << NAME_HASH_SHIFT) ^
1265 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1266 *name++;
1267 }
1268
1269 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1270 __le32 *value = (__le32 *)((char *)header +
1271 le16_to_cpu(entry->e_value_offs));
1272 for (n = (le32_to_cpu(entry->e_value_size) +
1273 EXT3_XATTR_ROUND) >> EXT3_XATTR_PAD_BITS; n; n--) {
1274 hash = (hash << VALUE_HASH_SHIFT) ^
1275 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1276 le32_to_cpu(*value++);
1277 }
1278 }
1279 entry->e_hash = cpu_to_le32(hash);
1280}
1281
1282#undef NAME_HASH_SHIFT
1283#undef VALUE_HASH_SHIFT
1284
1285#define BLOCK_HASH_SHIFT 16
1286
1287/*
1288 * ext3_xattr_rehash()
1289 *
1290 * Re-compute the extended attribute hash value after an entry has changed.
1291 */
1292static void ext3_xattr_rehash(struct ext3_xattr_header *header,
1293 struct ext3_xattr_entry *entry)
1294{
1295 struct ext3_xattr_entry *here;
1296 __u32 hash = 0;
1297
1298 ext3_xattr_hash_entry(header, entry);
1299 here = ENTRY(header+1);
1300 while (!IS_LAST_ENTRY(here)) {
1301 if (!here->e_hash) {
1302 /* Block is not shared if an entry's hash value == 0 */
1303 hash = 0;
1304 break;
1305 }
1306 hash = (hash << BLOCK_HASH_SHIFT) ^
1307 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1308 le32_to_cpu(here->e_hash);
1309 here = EXT3_XATTR_NEXT(here);
1310 }
1311 header->h_hash = cpu_to_le32(hash);
1312}
1313
1314#undef BLOCK_HASH_SHIFT
1315
1316int __init
1317init_ext3_xattr(void)
1318{
2aec7c52 1319 ext3_xattr_cache = mb_cache_create("ext3_xattr", 6);
1da177e4
LT		 1320 if (!ext3_xattr_cache)
1321 return -ENOMEM;
1322 return 0;
1323}
1324
1325void
1326exit_ext3_xattr(void)
1327{
1328 if (ext3_xattr_cache)
1329 mb_cache_destroy(ext3_xattr_cache);
1330 ext3_xattr_cache = NULL;
1331}
Linux 6.x block layer and io_uring tree(s)