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Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[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) {
78c3eb3c 549 if (free < EXT3_XATTR_LEN(name_len) +
1da177e4
LT		 550 EXT3_XATTR_SIZE(i->value_len))
551 return -ENOSPC;
552 }
553
554 if (i->value && s->not_found) {
555 /* Insert the new name. */
556 size_t size = EXT3_XATTR_LEN(name_len);
557 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
558 memmove((void *)s->here + size, s->here, rest);
559 memset(s->here, 0, size);
560 s->here->e_name_index = i->name_index;
561 s->here->e_name_len = name_len;
562 memcpy(s->here->e_name, i->name, name_len);
563 } else {
564 if (!s->here->e_value_block && s->here->e_value_size) {
565 void *first_val = s->base + min_offs;
566 size_t offs = le16_to_cpu(s->here->e_value_offs);
567 void *val = s->base + offs;
568 size_t size = EXT3_XATTR_SIZE(
569 le32_to_cpu(s->here->e_value_size));
570
571 if (i->value && size == EXT3_XATTR_SIZE(i->value_len)) {
572 /* The old and the new value have the same
573 size. Just replace. */
574 s->here->e_value_size =
575 cpu_to_le32(i->value_len);
576 memset(val + size - EXT3_XATTR_PAD, 0,
577 EXT3_XATTR_PAD); /* Clear pad bytes. */
578 memcpy(val, i->value, i->value_len);
579 return 0;
580 }
581
582 /* Remove the old value. */
583 memmove(first_val + size, first_val, val - first_val);
584 memset(first_val, 0, size);
585 s->here->e_value_size = 0;
586 s->here->e_value_offs = 0;
587 min_offs += size;
588
589 /* Adjust all value offsets. */
590 last = s->first;
591 while (!IS_LAST_ENTRY(last)) {
592 size_t o = le16_to_cpu(last->e_value_offs);
593 if (!last->e_value_block &&
594 last->e_value_size && o < offs)
595 last->e_value_offs =
596 cpu_to_le16(o + size);
597 last = EXT3_XATTR_NEXT(last);
598 }
599 }
600 if (!i->value) {
601 /* Remove the old name. */
602 size_t size = EXT3_XATTR_LEN(name_len);
603 last = ENTRY((void *)last - size);
604 memmove(s->here, (void *)s->here + size,
605 (void *)last - (void *)s->here + sizeof(__u32));
606 memset(last, 0, size);
607 }
608 }
609
610 if (i->value) {
611 /* Insert the new value. */
612 s->here->e_value_size = cpu_to_le32(i->value_len);
613 if (i->value_len) {
614 size_t size = EXT3_XATTR_SIZE(i->value_len);
615 void *val = s->base + min_offs - size;
616 s->here->e_value_offs = cpu_to_le16(min_offs - size);
617 memset(val + size - EXT3_XATTR_PAD, 0,
618 EXT3_XATTR_PAD); /* Clear the pad bytes. */
619 memcpy(val, i->value, i->value_len);
620 }
621 }
622 return 0;
623}
624
625struct ext3_xattr_block_find {
626 struct ext3_xattr_search s;
627 struct buffer_head *bh;
628};
629
381be254 630static int
1da177e4
LT		 631ext3_xattr_block_find(struct inode *inode, struct ext3_xattr_info *i,
632 struct ext3_xattr_block_find *bs)
633{
634 struct super_block *sb = inode->i_sb;
635 int error;
636
637 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
638 i->name_index, i->name, i->value, (long)i->value_len);
639
640 if (EXT3_I(inode)->i_file_acl) {
641 /* The inode already has an extended attribute block. */
642 bs->bh = sb_bread(sb, EXT3_I(inode)->i_file_acl);
643 error = -EIO;
644 if (!bs->bh)
645 goto cleanup;
646 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
647 atomic_read(&(bs->bh->b_count)),
648 le32_to_cpu(BHDR(bs->bh)->h_refcount));
649 if (ext3_xattr_check_block(bs->bh)) {
e05b6b52 650 ext3_error(sb, __func__,
eee194e7 651 "inode %lu: bad block "E3FSBLK, inode->i_ino,
1da177e4
LT		 652 EXT3_I(inode)->i_file_acl);
653 error = -EIO;
654 goto cleanup;
655 }
656 /* Find the named attribute. */
657 bs->s.base = BHDR(bs->bh);
658 bs->s.first = BFIRST(bs->bh);
659 bs->s.end = bs->bh->b_data + bs->bh->b_size;
660 bs->s.here = bs->s.first;
661 error = ext3_xattr_find_entry(&bs->s.here, i->name_index,
662 i->name, bs->bh->b_size, 1);
663 if (error && error != -ENODATA)
664 goto cleanup;
665 bs->s.not_found = error;
666 }
667 error = 0;
668
669cleanup:
670 return error;
671}
672
673static int
674ext3_xattr_block_set(handle_t *handle, struct inode *inode,
675 struct ext3_xattr_info *i,
676 struct ext3_xattr_block_find *bs)
677{
678 struct super_block *sb = inode->i_sb;
679 struct buffer_head *new_bh = NULL;
680 struct ext3_xattr_search *s = &bs->s;
681 struct mb_cache_entry *ce = NULL;
8a2bfdcb 682 int error = 0;
1da177e4
LT		 683
684#define header(x) ((struct ext3_xattr_header *)(x))
685
686 if (i->value && i->value_len > sb->s_blocksize)
687 return -ENOSPC;
688 if (s->base) {
689 ce = mb_cache_entry_get(ext3_xattr_cache, bs->bh->b_bdev,
690 bs->bh->b_blocknr);
8a2bfdcb
MC		 691 error = ext3_journal_get_write_access(handle, bs->bh);
692 if (error)
693 goto cleanup;
694 lock_buffer(bs->bh);
695
1da177e4
LT		 696 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
697 if (ce) {
698 mb_cache_entry_free(ce);
699 ce = NULL;
700 }
701 ea_bdebug(bs->bh, "modifying in-place");
1da177e4
LT		 702 error = ext3_xattr_set_entry(i, s);
703 if (!error) {
704 if (!IS_LAST_ENTRY(s->first))
705 ext3_xattr_rehash(header(s->base),
706 s->here);
707 ext3_xattr_cache_insert(bs->bh);
708 }
709 unlock_buffer(bs->bh);
710 if (error == -EIO)
711 goto bad_block;
712 if (!error)
713 error = ext3_journal_dirty_metadata(handle,
714 bs->bh);
715 if (error)
716 goto cleanup;
717 goto inserted;
718 } else {
719 int offset = (char *)s->here - bs->bh->b_data;
720
8a2bfdcb
MC		 721 unlock_buffer(bs->bh);
722 journal_release_buffer(handle, bs->bh);
723
1da177e4
LT		 724 if (ce) {
725 mb_cache_entry_release(ce);
726 ce = NULL;
727 }
728 ea_bdebug(bs->bh, "cloning");
c587f0c0 729 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1da177e4
LT		 730 error = -ENOMEM;
731 if (s->base == NULL)
732 goto cleanup;
733 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
734 s->first = ENTRY(header(s->base)+1);
735 header(s->base)->h_refcount = cpu_to_le32(1);
736 s->here = ENTRY(s->base + offset);
737 s->end = s->base + bs->bh->b_size;
738 }
739 } else {
740 /* Allocate a buffer where we construct the new block. */
c587f0c0 741 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1da177e4
LT		 742 /* assert(header == s->base) */
743 error = -ENOMEM;
744 if (s->base == NULL)
745 goto cleanup;
1da177e4
LT		 746 header(s->base)->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
747 header(s->base)->h_blocks = cpu_to_le32(1);
748 header(s->base)->h_refcount = cpu_to_le32(1);
749 s->first = ENTRY(header(s->base)+1);
750 s->here = ENTRY(header(s->base)+1);
751 s->end = s->base + sb->s_blocksize;
752 }
753
754 error = ext3_xattr_set_entry(i, s);
755 if (error == -EIO)
756 goto bad_block;
757 if (error)
758 goto cleanup;
759 if (!IS_LAST_ENTRY(s->first))
760 ext3_xattr_rehash(header(s->base), s->here);
761
762inserted:
763 if (!IS_LAST_ENTRY(s->first)) {
764 new_bh = ext3_xattr_cache_find(inode, header(s->base), &ce);
765 if (new_bh) {
766 /* We found an identical block in the cache. */
767 if (new_bh == bs->bh)
768 ea_bdebug(new_bh, "keeping");
769 else {
770 /* The old block is released after updating
771 the inode. */
5dd4056d
CH		 772 error = dquot_alloc_block(inode, 1);
773 if (error)
1da177e4
LT		 774 goto cleanup;
775 error = ext3_journal_get_write_access(handle,
776 new_bh);
777 if (error)
778 goto cleanup_dquot;
779 lock_buffer(new_bh);
50e8a289 780 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
1da177e4
LT		 781 ea_bdebug(new_bh, "reusing; refcount now=%d",
782 le32_to_cpu(BHDR(new_bh)->h_refcount));
783 unlock_buffer(new_bh);
784 error = ext3_journal_dirty_metadata(handle,
785 new_bh);
786 if (error)
787 goto cleanup_dquot;
788 }
789 mb_cache_entry_release(ce);
790 ce = NULL;
791 } else if (bs->bh && s->base == bs->bh->b_data) {
792 /* We were modifying this block in-place. */
793 ea_bdebug(bs->bh, "keeping this block");
794 new_bh = bs->bh;
795 get_bh(new_bh);
796 } else {
797 /* We need to allocate a new block */
1eaafeae
AM		 798 ext3_fsblk_t goal = ext3_group_first_block_no(sb,
799 EXT3_I(inode)->i_block_group);
ad95c5e9
JK		 800 ext3_fsblk_t block;
801
802 /*
803 * Protect us agaist concurrent allocations to the
804 * same inode from ext3_..._writepage(). Reservation
805 * code does not expect racing allocations.
806 */
807 mutex_lock(&EXT3_I(inode)->truncate_mutex);
808 block = ext3_new_block(handle, inode, goal, &error);
809 mutex_unlock(&EXT3_I(inode)->truncate_mutex);
1da177e4
LT		 810 if (error)
811 goto cleanup;
812 ea_idebug(inode, "creating block %d", block);
813
814 new_bh = sb_getblk(sb, block);
1b7d76e9 815 if (unlikely(!new_bh)) {
1da177e4
LT		 816getblk_failed:
817 ext3_free_blocks(handle, inode, block, 1);
c04e88e2 818 error = -ENOMEM;
1da177e4
LT		 819 goto cleanup;
820 }
821 lock_buffer(new_bh);
822 error = ext3_journal_get_create_access(handle, new_bh);
823 if (error) {
824 unlock_buffer(new_bh);
825 goto getblk_failed;
826 }
827 memcpy(new_bh->b_data, s->base, new_bh->b_size);
828 set_buffer_uptodate(new_bh);
829 unlock_buffer(new_bh);
830 ext3_xattr_cache_insert(new_bh);
831 error = ext3_journal_dirty_metadata(handle, new_bh);
832 if (error)
833 goto cleanup;
834 }
835 }
836
837 /* Update the inode. */
838 EXT3_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
839
840 /* Drop the previous xattr block. */
841 if (bs->bh && bs->bh != new_bh)
842 ext3_xattr_release_block(handle, inode, bs->bh);
843 error = 0;
844
845cleanup:
846 if (ce)
847 mb_cache_entry_release(ce);
848 brelse(new_bh);
849 if (!(bs->bh && s->base == bs->bh->b_data))
850 kfree(s->base);
851
852 return error;
853
854cleanup_dquot:
5dd4056d 855 dquot_free_block(inode, 1);
1da177e4
LT		 856 goto cleanup;
857
858bad_block:
e05b6b52 859 ext3_error(inode->i_sb, __func__,
eee194e7 860 "inode %lu: bad block "E3FSBLK, inode->i_ino,
1da177e4
LT		 861 EXT3_I(inode)->i_file_acl);
862 goto cleanup;
863
864#undef header
865}
866
867struct ext3_xattr_ibody_find {
868 struct ext3_xattr_search s;
869 struct ext3_iloc iloc;
870};
871
381be254 872static int
1da177e4
LT		 873ext3_xattr_ibody_find(struct inode *inode, struct ext3_xattr_info *i,
874 struct ext3_xattr_ibody_find *is)
875{
876 struct ext3_xattr_ibody_header *header;
877 struct ext3_inode *raw_inode;
878 int error;
879
880 if (EXT3_I(inode)->i_extra_isize == 0)
881 return 0;
882 raw_inode = ext3_raw_inode(&is->iloc);
883 header = IHDR(inode, raw_inode);
884 is->s.base = is->s.first = IFIRST(header);
885 is->s.here = is->s.first;
886 is->s.end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
9df93939 887 if (ext3_test_inode_state(inode, EXT3_STATE_XATTR)) {
1da177e4
LT		 888 error = ext3_xattr_check_names(IFIRST(header), is->s.end);
889 if (error)
890 return error;
891 /* Find the named attribute. */
892 error = ext3_xattr_find_entry(&is->s.here, i->name_index,
893 i->name, is->s.end -
894 (void *)is->s.base, 0);
895 if (error && error != -ENODATA)
896 return error;
897 is->s.not_found = error;
898 }
899 return 0;
900}
901
902static int
903ext3_xattr_ibody_set(handle_t *handle, struct inode *inode,
904 struct ext3_xattr_info *i,
905 struct ext3_xattr_ibody_find *is)
906{
907 struct ext3_xattr_ibody_header *header;
908 struct ext3_xattr_search *s = &is->s;
909 int error;
910
911 if (EXT3_I(inode)->i_extra_isize == 0)
912 return -ENOSPC;
913 error = ext3_xattr_set_entry(i, s);
914 if (error)
915 return error;
916 header = IHDR(inode, ext3_raw_inode(&is->iloc));
917 if (!IS_LAST_ENTRY(s->first)) {
918 header->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
9df93939 919 ext3_set_inode_state(inode, EXT3_STATE_XATTR);
1da177e4
LT		 920 } else {
921 header->h_magic = cpu_to_le32(0);
9df93939 922 ext3_clear_inode_state(inode, EXT3_STATE_XATTR);
1da177e4
LT		 923 }
924 return 0;
925}
926
927/*
928 * ext3_xattr_set_handle()
929 *
6e9510b0 930 * Create, replace or remove an extended attribute for this inode. Value
1da177e4
LT		 931 * is NULL to remove an existing extended attribute, and non-NULL to
932 * either replace an existing extended attribute, or create a new extended
933 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
934 * specify that an extended attribute must exist and must not exist
935 * previous to the call, respectively.
936 *
937 * Returns 0, or a negative error number on failure.
938 */
939int
940ext3_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
941 const char *name, const void *value, size_t value_len,
942 int flags)
943{
944 struct ext3_xattr_info i = {
945 .name_index = name_index,
946 .name = name,
947 .value = value,
948 .value_len = value_len,
949
950 };
951 struct ext3_xattr_ibody_find is = {
952 .s = { .not_found = -ENODATA, },
953 };
954 struct ext3_xattr_block_find bs = {
955 .s = { .not_found = -ENODATA, },
956 };
957 int error;
958
1da177e4
LT		 959 if (!name)
960 return -EINVAL;
961 if (strlen(name) > 255)
962 return -ERANGE;
963 down_write(&EXT3_I(inode)->xattr_sem);
964 error = ext3_get_inode_loc(inode, &is.iloc);
965 if (error)
966 goto cleanup;
967
d965736b
ES		 968 error = ext3_journal_get_write_access(handle, is.iloc.bh);
969 if (error)
970 goto cleanup;
971
9df93939 972 if (ext3_test_inode_state(inode, EXT3_STATE_NEW)) {
1da177e4
LT		 973 struct ext3_inode *raw_inode = ext3_raw_inode(&is.iloc);
974 memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
9df93939 975 ext3_clear_inode_state(inode, EXT3_STATE_NEW);
1da177e4
LT		 976 }
977
978 error = ext3_xattr_ibody_find(inode, &i, &is);
979 if (error)
980 goto cleanup;
981 if (is.s.not_found)
982 error = ext3_xattr_block_find(inode, &i, &bs);
983 if (error)
984 goto cleanup;
985 if (is.s.not_found && bs.s.not_found) {
986 error = -ENODATA;
987 if (flags & XATTR_REPLACE)
988 goto cleanup;
989 error = 0;
990 if (!value)
991 goto cleanup;
992 } else {
993 error = -EEXIST;
994 if (flags & XATTR_CREATE)
995 goto cleanup;
996 }
1da177e4
LT		 997 if (!value) {
998 if (!is.s.not_found)
999 error = ext3_xattr_ibody_set(handle, inode, &i, &is);
1000 else if (!bs.s.not_found)
1001 error = ext3_xattr_block_set(handle, inode, &i, &bs);
1002 } else {
1003 error = ext3_xattr_ibody_set(handle, inode, &i, &is);
1004 if (!error && !bs.s.not_found) {
1005 i.value = NULL;
1006 error = ext3_xattr_block_set(handle, inode, &i, &bs);
1007 } else if (error == -ENOSPC) {
7e01c8e5
TY		 1008 if (EXT3_I(inode)->i_file_acl && !bs.s.base) {
1009 error = ext3_xattr_block_find(inode, &i, &bs);
1010 if (error)
1011 goto cleanup;
1012 }
1da177e4
LT		 1013 error = ext3_xattr_block_set(handle, inode, &i, &bs);
1014 if (error)
1015 goto cleanup;
1016 if (!is.s.not_found) {
1017 i.value = NULL;
1018 error = ext3_xattr_ibody_set(handle, inode, &i,
1019 &is);
1020 }
1021 }
1022 }
1023 if (!error) {
1024 ext3_xattr_update_super_block(handle, inode->i_sb);
1025 inode->i_ctime = CURRENT_TIME_SEC;
1026 error = ext3_mark_iloc_dirty(handle, inode, &is.iloc);
1027 /*
1028 * The bh is consumed by ext3_mark_iloc_dirty, even with
1029 * error != 0.
1030 */
1031 is.iloc.bh = NULL;
1032 if (IS_SYNC(inode))
1033 handle->h_sync = 1;
1034 }
1035
1036cleanup:
1037 brelse(is.iloc.bh);
1038 brelse(bs.bh);
1039 up_write(&EXT3_I(inode)->xattr_sem);
1040 return error;
1041}
1042
1043/*
1044 * ext3_xattr_set()
1045 *
1046 * Like ext3_xattr_set_handle, but start from an inode. This extended
1047 * attribute modification is a filesystem transaction by itself.
1048 *
1049 * Returns 0, or a negative error number on failure.
1050 */
1051int
1052ext3_xattr_set(struct inode *inode, int name_index, const char *name,
1053 const void *value, size_t value_len, int flags)
1054{
1055 handle_t *handle;
1056 int error, retries = 0;
1057
1058retry:
1f54587b 1059 handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
1da177e4
LT		 1060 if (IS_ERR(handle)) {
1061 error = PTR_ERR(handle);
1062 } else {
1063 int error2;
1064
1065 error = ext3_xattr_set_handle(handle, inode, name_index, name,
1066 value, value_len, flags);
1067 error2 = ext3_journal_stop(handle);
1068 if (error == -ENOSPC &&
1069 ext3_should_retry_alloc(inode->i_sb, &retries))
1070 goto retry;
1071 if (error == 0)
1072 error = error2;
1073 }
1074
1075 return error;
1076}
1077
1078/*
1079 * ext3_xattr_delete_inode()
1080 *
1081 * Free extended attribute resources associated with this inode. This
1082 * is called immediately before an inode is freed. We have exclusive
1083 * access to the inode.
1084 */
1085void
1086ext3_xattr_delete_inode(handle_t *handle, struct inode *inode)
1087{
1088 struct buffer_head *bh = NULL;
1089
1090 if (!EXT3_I(inode)->i_file_acl)
1091 goto cleanup;
1092 bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
1093 if (!bh) {
e05b6b52 1094 ext3_error(inode->i_sb, __func__,
eee194e7 1095 "inode %lu: block "E3FSBLK" read error", inode->i_ino,
1da177e4
LT		 1096 EXT3_I(inode)->i_file_acl);
1097 goto cleanup;
1098 }
1099 if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
1100 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
e05b6b52 1101 ext3_error(inode->i_sb, __func__,
eee194e7 1102 "inode %lu: bad block "E3FSBLK, inode->i_ino,
1da177e4
LT		 1103 EXT3_I(inode)->i_file_acl);
1104 goto cleanup;
1105 }
1106 ext3_xattr_release_block(handle, inode, bh);
1107 EXT3_I(inode)->i_file_acl = 0;
1108
1109cleanup:
1110 brelse(bh);
1111}
1112
1113/*
1114 * ext3_xattr_put_super()
1115 *
1116 * This is called when a file system is unmounted.
1117 */
1118void
1119ext3_xattr_put_super(struct super_block *sb)
1120{
8c52ab42 1121 mb_cache_shrink(sb->s_bdev);
1da177e4
LT		 1122}
1123
1124/*
1125 * ext3_xattr_cache_insert()
1126 *
1127 * Create a new entry in the extended attribute cache, and insert
1128 * it unless such an entry is already in the cache.
1129 *
1130 * Returns 0, or a negative error number on failure.
1131 */
1132static void
1133ext3_xattr_cache_insert(struct buffer_head *bh)
1134{
1135 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1136 struct mb_cache_entry *ce;
1137 int error;
1138
335e92e8 1139 ce = mb_cache_entry_alloc(ext3_xattr_cache, GFP_NOFS);
1da177e4
LT		 1140 if (!ce) {
1141 ea_bdebug(bh, "out of memory");
1142 return;
1143 }
2aec7c52 1144 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1da177e4
LT		 1145 if (error) {
1146 mb_cache_entry_free(ce);
1147 if (error == -EBUSY) {
1148 ea_bdebug(bh, "already in cache");
1149 error = 0;
1150 }
1151 } else {
1152 ea_bdebug(bh, "inserting [%x]", (int)hash);
1153 mb_cache_entry_release(ce);
1154 }
1155}
1156
1157/*
1158 * ext3_xattr_cmp()
1159 *
1160 * Compare two extended attribute blocks for equality.
1161 *
1162 * Returns 0 if the blocks are equal, 1 if they differ, and
1163 * a negative error number on errors.
1164 */
1165static int
1166ext3_xattr_cmp(struct ext3_xattr_header *header1,
1167 struct ext3_xattr_header *header2)
1168{
1169 struct ext3_xattr_entry *entry1, *entry2;
1170
1171 entry1 = ENTRY(header1+1);
1172 entry2 = ENTRY(header2+1);
1173 while (!IS_LAST_ENTRY(entry1)) {
1174 if (IS_LAST_ENTRY(entry2))
1175 return 1;
1176 if (entry1->e_hash != entry2->e_hash ||
1177 entry1->e_name_index != entry2->e_name_index ||
1178 entry1->e_name_len != entry2->e_name_len ||
1179 entry1->e_value_size != entry2->e_value_size ||
1180 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1181 return 1;
1182 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1183 return -EIO;
1184 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1185 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1186 le32_to_cpu(entry1->e_value_size)))
1187 return 1;
1188
1189 entry1 = EXT3_XATTR_NEXT(entry1);
1190 entry2 = EXT3_XATTR_NEXT(entry2);
1191 }
1192 if (!IS_LAST_ENTRY(entry2))
1193 return 1;
1194 return 0;
1195}
1196
1197/*
1198 * ext3_xattr_cache_find()
1199 *
1200 * Find an identical extended attribute block.
1201 *
1202 * Returns a pointer to the block found, or NULL if such a block was
1203 * not found or an error occurred.
1204 */
1205static struct buffer_head *
1206ext3_xattr_cache_find(struct inode *inode, struct ext3_xattr_header *header,
1207 struct mb_cache_entry **pce)
1208{
1209 __u32 hash = le32_to_cpu(header->h_hash);
1210 struct mb_cache_entry *ce;
1211
1212 if (!header->h_hash)
1213 return NULL; /* never share */
1214 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1215again:
2aec7c52
AG		 1216 ce = mb_cache_entry_find_first(ext3_xattr_cache, inode->i_sb->s_bdev,
1217 hash);
1da177e4
LT		 1218 while (ce) {
1219 struct buffer_head *bh;
1220
1221 if (IS_ERR(ce)) {
1222 if (PTR_ERR(ce) == -EAGAIN)
1223 goto again;
1224 break;
1225 }
1226 bh = sb_bread(inode->i_sb, ce->e_block);
1227 if (!bh) {
e05b6b52 1228 ext3_error(inode->i_sb, __func__,
eee194e7 1229 "inode %lu: block %lu read error",
1da177e4
LT		 1230 inode->i_ino, (unsigned long) ce->e_block);
1231 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1232 EXT3_XATTR_REFCOUNT_MAX) {
1c2bf374 1233 ea_idebug(inode, "block %lu refcount %d>=%d",
1da177e4
LT		 1234 (unsigned long) ce->e_block,
1235 le32_to_cpu(BHDR(bh)->h_refcount),
1236 EXT3_XATTR_REFCOUNT_MAX);
1237 } else if (ext3_xattr_cmp(header, BHDR(bh)) == 0) {
1238 *pce = ce;
1239 return bh;
1240 }
1241 brelse(bh);
2aec7c52 1242 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1da177e4
LT		 1243 }
1244 return NULL;
1245}
1246
1247#define NAME_HASH_SHIFT 5
1248#define VALUE_HASH_SHIFT 16
1249
1250/*
1251 * ext3_xattr_hash_entry()
1252 *
1253 * Compute the hash of an extended attribute.
1254 */
1255static inline void ext3_xattr_hash_entry(struct ext3_xattr_header *header,
1256 struct ext3_xattr_entry *entry)
1257{
1258 __u32 hash = 0;
1259 char *name = entry->e_name;
1260 int n;
1261
1262 for (n=0; n < entry->e_name_len; n++) {
1263 hash = (hash << NAME_HASH_SHIFT) ^
1264 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1265 *name++;
1266 }
1267
1268 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1269 __le32 *value = (__le32 *)((char *)header +
1270 le16_to_cpu(entry->e_value_offs));
1271 for (n = (le32_to_cpu(entry->e_value_size) +
1272 EXT3_XATTR_ROUND) >> EXT3_XATTR_PAD_BITS; n; n--) {
1273 hash = (hash << VALUE_HASH_SHIFT) ^
1274 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1275 le32_to_cpu(*value++);
1276 }
1277 }
1278 entry->e_hash = cpu_to_le32(hash);
1279}
1280
1281#undef NAME_HASH_SHIFT
1282#undef VALUE_HASH_SHIFT
1283
1284#define BLOCK_HASH_SHIFT 16
1285
1286/*
1287 * ext3_xattr_rehash()
1288 *
1289 * Re-compute the extended attribute hash value after an entry has changed.
1290 */
1291static void ext3_xattr_rehash(struct ext3_xattr_header *header,
1292 struct ext3_xattr_entry *entry)
1293{
1294 struct ext3_xattr_entry *here;
1295 __u32 hash = 0;
1296
1297 ext3_xattr_hash_entry(header, entry);
1298 here = ENTRY(header+1);
1299 while (!IS_LAST_ENTRY(here)) {
1300 if (!here->e_hash) {
1301 /* Block is not shared if an entry's hash value == 0 */
1302 hash = 0;
1303 break;
1304 }
1305 hash = (hash << BLOCK_HASH_SHIFT) ^
1306 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1307 le32_to_cpu(here->e_hash);
1308 here = EXT3_XATTR_NEXT(here);
1309 }
1310 header->h_hash = cpu_to_le32(hash);
1311}
1312
1313#undef BLOCK_HASH_SHIFT
1314
1315int __init
1316init_ext3_xattr(void)
1317{
2aec7c52 1318 ext3_xattr_cache = mb_cache_create("ext3_xattr", 6);
1da177e4
LT		 1319 if (!ext3_xattr_cache)
1320 return -ENOMEM;
1321 return 0;
1322}
1323
1324void
1325exit_ext3_xattr(void)
1326{
1327 if (ext3_xattr_cache)
1328 mb_cache_destroy(ext3_xattr_cache);
1329 ext3_xattr_cache = NULL;
1330}
Linux 6.x block layer and io_uring tree(s)