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ext4: use ext4_group_first_block_no()
[linux-2.6/kmemtrace.git] / fs / ext4 / xattr.c
blobbc1d7daac8eb80ec5ec01b59cfc58f210377672b
1 /*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
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 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53 #include <linux/init.h>
54 #include <linux/fs.h>
55 #include <linux/slab.h>
56 #include <linux/ext4_jbd2.h>
57 #include <linux/ext4_fs.h>
58 #include <linux/mbcache.h>
59 #include <linux/quotaops.h>
60 #include <linux/rwsem.h>
61 #include "xattr.h"
62 #include "acl.h"
63
64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
68
69 #ifdef EXT4_XATTR_DEBUG
70 # define ea_idebug(inode, f...) do { \
71 printk(KERN_DEBUG "inode %s:%lu: ", \
72 inode->i_sb->s_id, inode->i_ino); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76 # define ea_bdebug(bh, f...) do { \
77 char b[BDEVNAME_SIZE]; \
78 printk(KERN_DEBUG "block %s:%lu: ", \
79 bdevname(bh->b_bdev, b), \
80 (unsigned long) bh->b_blocknr); \
81 printk(f); \
82 printk("\n"); \
83 } while (0)
84 #else
85 # define ea_idebug(f...)
86 # define ea_bdebug(f...)
87 #endif
88
89 static void ext4_xattr_cache_insert(struct buffer_head *);
90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
91 struct ext4_xattr_header *,
92 struct mb_cache_entry **);
93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
94 struct ext4_xattr_entry *);
95
96 static struct mb_cache *ext4_xattr_cache;
97
98 static struct xattr_handler *ext4_xattr_handler_map[] = {
99 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
100 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
101 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
102 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
103 #endif
104 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
105 #ifdef CONFIG_EXT4DEV_FS_SECURITY
106 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
107 #endif
108 };
109
110 struct xattr_handler *ext4_xattr_handlers[] = {
111 &ext4_xattr_user_handler,
112 &ext4_xattr_trusted_handler,
113 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
114 &ext4_xattr_acl_access_handler,
115 &ext4_xattr_acl_default_handler,
116 #endif
117 #ifdef CONFIG_EXT4DEV_FS_SECURITY
118 &ext4_xattr_security_handler,
119 #endif
120 NULL
121 };
122
123 static inline struct xattr_handler *
124 ext4_xattr_handler(int name_index)
125 {
126 struct xattr_handler *handler = NULL;
127
128 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
129 handler = ext4_xattr_handler_map[name_index];
130 return handler;
131 }
132
133 /*
134 * Inode operation listxattr()
135 *
136 * dentry->d_inode->i_mutex: don't care
137 */
138 ssize_t
139 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
140 {
141 return ext4_xattr_list(dentry->d_inode, buffer, size);
142 }
143
144 static int
145 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
146 {
147 while (!IS_LAST_ENTRY(entry)) {
148 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
149 if ((void *)next >= end)
150 return -EIO;
151 entry = next;
152 }
153 return 0;
154 }
155
156 static inline int
157 ext4_xattr_check_block(struct buffer_head *bh)
158 {
159 int error;
160
161 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
162 BHDR(bh)->h_blocks != cpu_to_le32(1))
163 return -EIO;
164 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
165 return error;
166 }
167
168 static inline int
169 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
170 {
171 size_t value_size = le32_to_cpu(entry->e_value_size);
172
173 if (entry->e_value_block != 0 || value_size > size ||
174 le16_to_cpu(entry->e_value_offs) + value_size > size)
175 return -EIO;
176 return 0;
177 }
178
179 static int
180 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
181 const char *name, size_t size, int sorted)
182 {
183 struct ext4_xattr_entry *entry;
184 size_t name_len;
185 int cmp = 1;
186
187 if (name == NULL)
188 return -EINVAL;
189 name_len = strlen(name);
190 entry = *pentry;
191 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
192 cmp = name_index - entry->e_name_index;
193 if (!cmp)
194 cmp = name_len - entry->e_name_len;
195 if (!cmp)
196 cmp = memcmp(name, entry->e_name, name_len);
197 if (cmp <= 0 && (sorted || cmp == 0))
198 break;
199 }
200 *pentry = entry;
201 if (!cmp && ext4_xattr_check_entry(entry, size))
202 return -EIO;
203 return cmp ? -ENODATA : 0;
204 }
205
206 static int
207 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
208 void *buffer, size_t buffer_size)
209 {
210 struct buffer_head *bh = NULL;
211 struct ext4_xattr_entry *entry;
212 size_t size;
213 int error;
214
215 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
216 name_index, name, buffer, (long)buffer_size);
217
218 error = -ENODATA;
219 if (!EXT4_I(inode)->i_file_acl)
220 goto cleanup;
221 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
222 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
223 if (!bh)
224 goto cleanup;
225 ea_bdebug(bh, "b_count=%d, refcount=%d",
226 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
227 if (ext4_xattr_check_block(bh)) {
228 bad_block: ext4_error(inode->i_sb, __FUNCTION__,
229 "inode %lu: bad block %llu", inode->i_ino,
230 EXT4_I(inode)->i_file_acl);
231 error = -EIO;
232 goto cleanup;
233 }
234 ext4_xattr_cache_insert(bh);
235 entry = BFIRST(bh);
236 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
237 if (error == -EIO)
238 goto bad_block;
239 if (error)
240 goto cleanup;
241 size = le32_to_cpu(entry->e_value_size);
242 if (buffer) {
243 error = -ERANGE;
244 if (size > buffer_size)
245 goto cleanup;
246 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
247 size);
248 }
249 error = size;
250
251 cleanup:
252 brelse(bh);
253 return error;
254 }
255
256 static int
257 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
258 void *buffer, size_t buffer_size)
259 {
260 struct ext4_xattr_ibody_header *header;
261 struct ext4_xattr_entry *entry;
262 struct ext4_inode *raw_inode;
263 struct ext4_iloc iloc;
264 size_t size;
265 void *end;
266 int error;
267
268 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
269 return -ENODATA;
270 error = ext4_get_inode_loc(inode, &iloc);
271 if (error)
272 return error;
273 raw_inode = ext4_raw_inode(&iloc);
274 header = IHDR(inode, raw_inode);
275 entry = IFIRST(header);
276 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
277 error = ext4_xattr_check_names(entry, end);
278 if (error)
279 goto cleanup;
280 error = ext4_xattr_find_entry(&entry, name_index, name,
281 end - (void *)entry, 0);
282 if (error)
283 goto cleanup;
284 size = le32_to_cpu(entry->e_value_size);
285 if (buffer) {
286 error = -ERANGE;
287 if (size > buffer_size)
288 goto cleanup;
289 memcpy(buffer, (void *)IFIRST(header) +
290 le16_to_cpu(entry->e_value_offs), size);
291 }
292 error = size;
293
294 cleanup:
295 brelse(iloc.bh);
296 return error;
297 }
298
299 /*
300 * ext4_xattr_get()
301 *
302 * Copy an extended attribute into the buffer
303 * provided, or compute the buffer size required.
304 * Buffer is NULL to compute the size of the buffer required.
305 *
306 * Returns a negative error number on failure, or the number of bytes
307 * used / required on success.
308 */
309 int
310 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
311 void *buffer, size_t buffer_size)
312 {
313 int error;
314
315 down_read(&EXT4_I(inode)->xattr_sem);
316 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
317 buffer_size);
318 if (error == -ENODATA)
319 error = ext4_xattr_block_get(inode, name_index, name, buffer,
320 buffer_size);
321 up_read(&EXT4_I(inode)->xattr_sem);
322 return error;
323 }
324
325 static int
326 ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry,
327 char *buffer, size_t buffer_size)
328 {
329 size_t rest = buffer_size;
330
331 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
332 struct xattr_handler *handler =
333 ext4_xattr_handler(entry->e_name_index);
334
335 if (handler) {
336 size_t size = handler->list(inode, buffer, rest,
337 entry->e_name,
338 entry->e_name_len);
339 if (buffer) {
340 if (size > rest)
341 return -ERANGE;
342 buffer += size;
343 }
344 rest -= size;
345 }
346 }
347 return buffer_size - rest;
348 }
349
350 static int
351 ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
352 {
353 struct buffer_head *bh = NULL;
354 int error;
355
356 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
357 buffer, (long)buffer_size);
358
359 error = 0;
360 if (!EXT4_I(inode)->i_file_acl)
361 goto cleanup;
362 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
363 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
364 error = -EIO;
365 if (!bh)
366 goto cleanup;
367 ea_bdebug(bh, "b_count=%d, refcount=%d",
368 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
369 if (ext4_xattr_check_block(bh)) {
370 ext4_error(inode->i_sb, __FUNCTION__,
371 "inode %lu: bad block %llu", inode->i_ino,
372 EXT4_I(inode)->i_file_acl);
373 error = -EIO;
374 goto cleanup;
375 }
376 ext4_xattr_cache_insert(bh);
377 error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
378
379 cleanup:
380 brelse(bh);
381
382 return error;
383 }
384
385 static int
386 ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
387 {
388 struct ext4_xattr_ibody_header *header;
389 struct ext4_inode *raw_inode;
390 struct ext4_iloc iloc;
391 void *end;
392 int error;
393
394 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
395 return 0;
396 error = ext4_get_inode_loc(inode, &iloc);
397 if (error)
398 return error;
399 raw_inode = ext4_raw_inode(&iloc);
400 header = IHDR(inode, raw_inode);
401 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
402 error = ext4_xattr_check_names(IFIRST(header), end);
403 if (error)
404 goto cleanup;
405 error = ext4_xattr_list_entries(inode, IFIRST(header),
406 buffer, buffer_size);
407
408 cleanup:
409 brelse(iloc.bh);
410 return error;
411 }
412
413 /*
414 * ext4_xattr_list()
415 *
416 * Copy a list of attribute names into the buffer
417 * provided, or compute the buffer size required.
418 * Buffer is NULL to compute the size of the buffer required.
419 *
420 * Returns a negative error number on failure, or the number of bytes
421 * used / required on success.
422 */
423 int
424 ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
425 {
426 int i_error, b_error;
427
428 down_read(&EXT4_I(inode)->xattr_sem);
429 i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size);
430 if (i_error < 0) {
431 b_error = 0;
432 } else {
433 if (buffer) {
434 buffer += i_error;
435 buffer_size -= i_error;
436 }
437 b_error = ext4_xattr_block_list(inode, buffer, buffer_size);
438 if (b_error < 0)
439 i_error = 0;
440 }
441 up_read(&EXT4_I(inode)->xattr_sem);
442 return i_error + b_error;
443 }
444
445 /*
446 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
447 * not set, set it.
448 */
449 static void ext4_xattr_update_super_block(handle_t *handle,
450 struct super_block *sb)
451 {
452 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
453 return;
454
455 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
456 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
457 sb->s_dirt = 1;
458 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
459 }
460 }
461
462 /*
463 * Release the xattr block BH: If the reference count is > 1, decrement
464 * it; otherwise free the block.
465 */
466 static void
467 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
468 struct buffer_head *bh)
469 {
470 struct mb_cache_entry *ce = NULL;
471 int error = 0;
472
473 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
474 error = ext4_journal_get_write_access(handle, bh);
475 if (error)
476 goto out;
477
478 lock_buffer(bh);
479 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
480 ea_bdebug(bh, "refcount now=0; freeing");
481 if (ce)
482 mb_cache_entry_free(ce);
483 ext4_free_blocks(handle, inode, bh->b_blocknr, 1, 1);
484 get_bh(bh);
485 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
486 } else {
487 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
488 error = ext4_journal_dirty_metadata(handle, bh);
489 if (IS_SYNC(inode))
490 handle->h_sync = 1;
491 DQUOT_FREE_BLOCK(inode, 1);
492 ea_bdebug(bh, "refcount now=%d; releasing",
493 le32_to_cpu(BHDR(bh)->h_refcount));
494 if (ce)
495 mb_cache_entry_release(ce);
496 }
497 unlock_buffer(bh);
498 out:
499 ext4_std_error(inode->i_sb, error);
500 return;
501 }
502
503 /*
504 * Find the available free space for EAs. This also returns the total number of
505 * bytes used by EA entries.
506 */
507 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
508 size_t *min_offs, void *base, int *total)
509 {
510 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
511 *total += EXT4_XATTR_LEN(last->e_name_len);
512 if (!last->e_value_block && last->e_value_size) {
513 size_t offs = le16_to_cpu(last->e_value_offs);
514 if (offs < *min_offs)
515 *min_offs = offs;
516 }
517 }
518 return (*min_offs - ((void *)last - base) - sizeof(__u32));
519 }
520
521 struct ext4_xattr_info {
522 int name_index;
523 const char *name;
524 const void *value;
525 size_t value_len;
526 };
527
528 struct ext4_xattr_search {
529 struct ext4_xattr_entry *first;
530 void *base;
531 void *end;
532 struct ext4_xattr_entry *here;
533 int not_found;
534 };
535
536 static int
537 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
538 {
539 struct ext4_xattr_entry *last;
540 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
541
542 /* Compute min_offs and last. */
543 last = s->first;
544 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
545 if (!last->e_value_block && last->e_value_size) {
546 size_t offs = le16_to_cpu(last->e_value_offs);
547 if (offs < min_offs)
548 min_offs = offs;
549 }
550 }
551 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
552 if (!s->not_found) {
553 if (!s->here->e_value_block && s->here->e_value_size) {
554 size_t size = le32_to_cpu(s->here->e_value_size);
555 free += EXT4_XATTR_SIZE(size);
556 }
557 free += EXT4_XATTR_LEN(name_len);
558 }
559 if (i->value) {
560 if (free < EXT4_XATTR_SIZE(i->value_len) ||
561 free < EXT4_XATTR_LEN(name_len) +
562 EXT4_XATTR_SIZE(i->value_len))
563 return -ENOSPC;
564 }
565
566 if (i->value && s->not_found) {
567 /* Insert the new name. */
568 size_t size = EXT4_XATTR_LEN(name_len);
569 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
570 memmove((void *)s->here + size, s->here, rest);
571 memset(s->here, 0, size);
572 s->here->e_name_index = i->name_index;
573 s->here->e_name_len = name_len;
574 memcpy(s->here->e_name, i->name, name_len);
575 } else {
576 if (!s->here->e_value_block && s->here->e_value_size) {
577 void *first_val = s->base + min_offs;
578 size_t offs = le16_to_cpu(s->here->e_value_offs);
579 void *val = s->base + offs;
580 size_t size = EXT4_XATTR_SIZE(
581 le32_to_cpu(s->here->e_value_size));
582
583 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
584 /* The old and the new value have the same
585 size. Just replace. */
586 s->here->e_value_size =
587 cpu_to_le32(i->value_len);
588 memset(val + size - EXT4_XATTR_PAD, 0,
589 EXT4_XATTR_PAD); /* Clear pad bytes. */
590 memcpy(val, i->value, i->value_len);
591 return 0;
592 }
593
594 /* Remove the old value. */
595 memmove(first_val + size, first_val, val - first_val);
596 memset(first_val, 0, size);
597 s->here->e_value_size = 0;
598 s->here->e_value_offs = 0;
599 min_offs += size;
600
601 /* Adjust all value offsets. */
602 last = s->first;
603 while (!IS_LAST_ENTRY(last)) {
604 size_t o = le16_to_cpu(last->e_value_offs);
605 if (!last->e_value_block &&
606 last->e_value_size && o < offs)
607 last->e_value_offs =
608 cpu_to_le16(o + size);
609 last = EXT4_XATTR_NEXT(last);
610 }
611 }
612 if (!i->value) {
613 /* Remove the old name. */
614 size_t size = EXT4_XATTR_LEN(name_len);
615 last = ENTRY((void *)last - size);
616 memmove(s->here, (void *)s->here + size,
617 (void *)last - (void *)s->here + sizeof(__u32));
618 memset(last, 0, size);
619 }
620 }
621
622 if (i->value) {
623 /* Insert the new value. */
624 s->here->e_value_size = cpu_to_le32(i->value_len);
625 if (i->value_len) {
626 size_t size = EXT4_XATTR_SIZE(i->value_len);
627 void *val = s->base + min_offs - size;
628 s->here->e_value_offs = cpu_to_le16(min_offs - size);
629 memset(val + size - EXT4_XATTR_PAD, 0,
630 EXT4_XATTR_PAD); /* Clear the pad bytes. */
631 memcpy(val, i->value, i->value_len);
632 }
633 }
634 return 0;
635 }
636
637 struct ext4_xattr_block_find {
638 struct ext4_xattr_search s;
639 struct buffer_head *bh;
640 };
641
642 static int
643 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
644 struct ext4_xattr_block_find *bs)
645 {
646 struct super_block *sb = inode->i_sb;
647 int error;
648
649 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
650 i->name_index, i->name, i->value, (long)i->value_len);
651
652 if (EXT4_I(inode)->i_file_acl) {
653 /* The inode already has an extended attribute block. */
654 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
655 error = -EIO;
656 if (!bs->bh)
657 goto cleanup;
658 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
659 atomic_read(&(bs->bh->b_count)),
660 le32_to_cpu(BHDR(bs->bh)->h_refcount));
661 if (ext4_xattr_check_block(bs->bh)) {
662 ext4_error(sb, __FUNCTION__,
663 "inode %lu: bad block %llu", inode->i_ino,
664 EXT4_I(inode)->i_file_acl);
665 error = -EIO;
666 goto cleanup;
667 }
668 /* Find the named attribute. */
669 bs->s.base = BHDR(bs->bh);
670 bs->s.first = BFIRST(bs->bh);
671 bs->s.end = bs->bh->b_data + bs->bh->b_size;
672 bs->s.here = bs->s.first;
673 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
674 i->name, bs->bh->b_size, 1);
675 if (error && error != -ENODATA)
676 goto cleanup;
677 bs->s.not_found = error;
678 }
679 error = 0;
680
681 cleanup:
682 return error;
683 }
684
685 static int
686 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
687 struct ext4_xattr_info *i,
688 struct ext4_xattr_block_find *bs)
689 {
690 struct super_block *sb = inode->i_sb;
691 struct buffer_head *new_bh = NULL;
692 struct ext4_xattr_search *s = &bs->s;
693 struct mb_cache_entry *ce = NULL;
694 int error = 0;
695
696 #define header(x) ((struct ext4_xattr_header *)(x))
697
698 if (i->value && i->value_len > sb->s_blocksize)
699 return -ENOSPC;
700 if (s->base) {
701 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
702 bs->bh->b_blocknr);
703 error = ext4_journal_get_write_access(handle, bs->bh);
704 if (error)
705 goto cleanup;
706 lock_buffer(bs->bh);
707
708 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
709 if (ce) {
710 mb_cache_entry_free(ce);
711 ce = NULL;
712 }
713 ea_bdebug(bs->bh, "modifying in-place");
714 error = ext4_xattr_set_entry(i, s);
715 if (!error) {
716 if (!IS_LAST_ENTRY(s->first))
717 ext4_xattr_rehash(header(s->base),
718 s->here);
719 ext4_xattr_cache_insert(bs->bh);
720 }
721 unlock_buffer(bs->bh);
722 if (error == -EIO)
723 goto bad_block;
724 if (!error)
725 error = ext4_journal_dirty_metadata(handle,
726 bs->bh);
727 if (error)
728 goto cleanup;
729 goto inserted;
730 } else {
731 int offset = (char *)s->here - bs->bh->b_data;
732
733 unlock_buffer(bs->bh);
734 jbd2_journal_release_buffer(handle, bs->bh);
735 if (ce) {
736 mb_cache_entry_release(ce);
737 ce = NULL;
738 }
739 ea_bdebug(bs->bh, "cloning");
740 s->base = kmalloc(bs->bh->b_size, GFP_KERNEL);
741 error = -ENOMEM;
742 if (s->base == NULL)
743 goto cleanup;
744 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
745 s->first = ENTRY(header(s->base)+1);
746 header(s->base)->h_refcount = cpu_to_le32(1);
747 s->here = ENTRY(s->base + offset);
748 s->end = s->base + bs->bh->b_size;
749 }
750 } else {
751 /* Allocate a buffer where we construct the new block. */
752 s->base = kzalloc(sb->s_blocksize, GFP_KERNEL);
753 /* assert(header == s->base) */
754 error = -ENOMEM;
755 if (s->base == NULL)
756 goto cleanup;
757 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
758 header(s->base)->h_blocks = cpu_to_le32(1);
759 header(s->base)->h_refcount = cpu_to_le32(1);
760 s->first = ENTRY(header(s->base)+1);
761 s->here = ENTRY(header(s->base)+1);
762 s->end = s->base + sb->s_blocksize;
763 }
764
765 error = ext4_xattr_set_entry(i, s);
766 if (error == -EIO)
767 goto bad_block;
768 if (error)
769 goto cleanup;
770 if (!IS_LAST_ENTRY(s->first))
771 ext4_xattr_rehash(header(s->base), s->here);
772
773 inserted:
774 if (!IS_LAST_ENTRY(s->first)) {
775 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
776 if (new_bh) {
777 /* We found an identical block in the cache. */
778 if (new_bh == bs->bh)
779 ea_bdebug(new_bh, "keeping");
780 else {
781 /* The old block is released after updating
782 the inode. */
783 error = -EDQUOT;
784 if (DQUOT_ALLOC_BLOCK(inode, 1))
785 goto cleanup;
786 error = ext4_journal_get_write_access(handle,
787 new_bh);
788 if (error)
789 goto cleanup_dquot;
790 lock_buffer(new_bh);
791 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
792 ea_bdebug(new_bh, "reusing; refcount now=%d",
793 le32_to_cpu(BHDR(new_bh)->h_refcount));
794 unlock_buffer(new_bh);
795 error = ext4_journal_dirty_metadata(handle,
796 new_bh);
797 if (error)
798 goto cleanup_dquot;
799 }
800 mb_cache_entry_release(ce);
801 ce = NULL;
802 } else if (bs->bh && s->base == bs->bh->b_data) {
803 /* We were modifying this block in-place. */
804 ea_bdebug(bs->bh, "keeping this block");
805 new_bh = bs->bh;
806 get_bh(new_bh);
807 } else {
808 /* We need to allocate a new block */
809 ext4_fsblk_t goal = ext4_group_first_block_no(sb,
810 EXT4_I(inode)->i_block_group);
811 ext4_fsblk_t block = ext4_new_block(handle, inode,
812 goal, &error);
813 if (error)
814 goto cleanup;
815 ea_idebug(inode, "creating block %d", block);
816
817 new_bh = sb_getblk(sb, block);
818 if (!new_bh) {
819 getblk_failed:
820 ext4_free_blocks(handle, inode, block, 1, 1);
821 error = -EIO;
822 goto cleanup;
823 }
824 lock_buffer(new_bh);
825 error = ext4_journal_get_create_access(handle, new_bh);
826 if (error) {
827 unlock_buffer(new_bh);
828 goto getblk_failed;
829 }
830 memcpy(new_bh->b_data, s->base, new_bh->b_size);
831 set_buffer_uptodate(new_bh);
832 unlock_buffer(new_bh);
833 ext4_xattr_cache_insert(new_bh);
834 error = ext4_journal_dirty_metadata(handle, new_bh);
835 if (error)
836 goto cleanup;
837 }
838 }
839
840 /* Update the inode. */
841 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
842
843 /* Drop the previous xattr block. */
844 if (bs->bh && bs->bh != new_bh)
845 ext4_xattr_release_block(handle, inode, bs->bh);
846 error = 0;
847
848 cleanup:
849 if (ce)
850 mb_cache_entry_release(ce);
851 brelse(new_bh);
852 if (!(bs->bh && s->base == bs->bh->b_data))
853 kfree(s->base);
854
855 return error;
856
857 cleanup_dquot:
858 DQUOT_FREE_BLOCK(inode, 1);
859 goto cleanup;
860
861 bad_block:
862 ext4_error(inode->i_sb, __FUNCTION__,
863 "inode %lu: bad block %llu", inode->i_ino,
864 EXT4_I(inode)->i_file_acl);
865 goto cleanup;
866
867 #undef header
868 }
869
870 struct ext4_xattr_ibody_find {
871 struct ext4_xattr_search s;
872 struct ext4_iloc iloc;
873 };
874
875 static int
876 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
877 struct ext4_xattr_ibody_find *is)
878 {
879 struct ext4_xattr_ibody_header *header;
880 struct ext4_inode *raw_inode;
881 int error;
882
883 if (EXT4_I(inode)->i_extra_isize == 0)
884 return 0;
885 raw_inode = ext4_raw_inode(&is->iloc);
886 header = IHDR(inode, raw_inode);
887 is->s.base = is->s.first = IFIRST(header);
888 is->s.here = is->s.first;
889 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
890 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
891 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
892 if (error)
893 return error;
894 /* Find the named attribute. */
895 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
896 i->name, is->s.end -
897 (void *)is->s.base, 0);
898 if (error && error != -ENODATA)
899 return error;
900 is->s.not_found = error;
901 }
902 return 0;
903 }
904
905 static int
906 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
907 struct ext4_xattr_info *i,
908 struct ext4_xattr_ibody_find *is)
909 {
910 struct ext4_xattr_ibody_header *header;
911 struct ext4_xattr_search *s = &is->s;
912 int error;
913
914 if (EXT4_I(inode)->i_extra_isize == 0)
915 return -ENOSPC;
916 error = ext4_xattr_set_entry(i, s);
917 if (error)
918 return error;
919 header = IHDR(inode, ext4_raw_inode(&is->iloc));
920 if (!IS_LAST_ENTRY(s->first)) {
921 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
922 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
923 } else {
924 header->h_magic = cpu_to_le32(0);
925 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
926 }
927 return 0;
928 }
929
930 /*
931 * ext4_xattr_set_handle()
932 *
933 * Create, replace or remove an extended attribute for this inode. Buffer
934 * is NULL to remove an existing extended attribute, and non-NULL to
935 * either replace an existing extended attribute, or create a new extended
936 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
937 * specify that an extended attribute must exist and must not exist
938 * previous to the call, respectively.
939 *
940 * Returns 0, or a negative error number on failure.
941 */
942 int
943 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
944 const char *name, const void *value, size_t value_len,
945 int flags)
946 {
947 struct ext4_xattr_info i = {
948 .name_index = name_index,
949 .name = name,
950 .value = value,
951 .value_len = value_len,
952
953 };
954 struct ext4_xattr_ibody_find is = {
955 .s = { .not_found = -ENODATA, },
956 };
957 struct ext4_xattr_block_find bs = {
958 .s = { .not_found = -ENODATA, },
959 };
960 int error;
961
962 if (!name)
963 return -EINVAL;
964 if (strlen(name) > 255)
965 return -ERANGE;
966 down_write(&EXT4_I(inode)->xattr_sem);
967 error = ext4_get_inode_loc(inode, &is.iloc);
968 if (error)
969 goto cleanup;
970
971 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
972 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
973 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
974 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
975 }
976
977 error = ext4_xattr_ibody_find(inode, &i, &is);
978 if (error)
979 goto cleanup;
980 if (is.s.not_found)
981 error = ext4_xattr_block_find(inode, &i, &bs);
982 if (error)
983 goto cleanup;
984 if (is.s.not_found && bs.s.not_found) {
985 error = -ENODATA;
986 if (flags & XATTR_REPLACE)
987 goto cleanup;
988 error = 0;
989 if (!value)
990 goto cleanup;
991 } else {
992 error = -EEXIST;
993 if (flags & XATTR_CREATE)
994 goto cleanup;
995 }
996 error = ext4_journal_get_write_access(handle, is.iloc.bh);
997 if (error)
998 goto cleanup;
999 if (!value) {
1000 if (!is.s.not_found)
1001 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1002 else if (!bs.s.not_found)
1003 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1004 } else {
1005 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1006 if (!error && !bs.s.not_found) {
1007 i.value = NULL;
1008 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1009 } else if (error == -ENOSPC) {
1010 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1011 if (error)
1012 goto cleanup;
1013 if (!is.s.not_found) {
1014 i.value = NULL;
1015 error = ext4_xattr_ibody_set(handle, inode, &i,
1016 &is);
1017 }
1018 }
1019 }
1020 if (!error) {
1021 ext4_xattr_update_super_block(handle, inode->i_sb);
1022 inode->i_ctime = ext4_current_time(inode);
1023 if (!value)
1024 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1025 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1026 /*
1027 * The bh is consumed by ext4_mark_iloc_dirty, even with
1028 * error != 0.
1029 */
1030 is.iloc.bh = NULL;
1031 if (IS_SYNC(inode))
1032 handle->h_sync = 1;
1033 }
1034
1035 cleanup:
1036 brelse(is.iloc.bh);
1037 brelse(bs.bh);
1038 up_write(&EXT4_I(inode)->xattr_sem);
1039 return error;
1040 }
1041
1042 /*
1043 * ext4_xattr_set()
1044 *
1045 * Like ext4_xattr_set_handle, but start from an inode. This extended
1046 * attribute modification is a filesystem transaction by itself.
1047 *
1048 * Returns 0, or a negative error number on failure.
1049 */
1050 int
1051 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1052 const void *value, size_t value_len, int flags)
1053 {
1054 handle_t *handle;
1055 int error, retries = 0;
1056
1057 retry:
1058 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1059 if (IS_ERR(handle)) {
1060 error = PTR_ERR(handle);
1061 } else {
1062 int error2;
1063
1064 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1065 value, value_len, flags);
1066 error2 = ext4_journal_stop(handle);
1067 if (error == -ENOSPC &&
1068 ext4_should_retry_alloc(inode->i_sb, &retries))
1069 goto retry;
1070 if (error == 0)
1071 error = error2;
1072 }
1073
1074 return error;
1075 }
1076
1077 /*
1078 * Shift the EA entries in the inode to create space for the increased
1079 * i_extra_isize.
1080 */
1081 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1082 int value_offs_shift, void *to,
1083 void *from, size_t n, int blocksize)
1084 {
1085 struct ext4_xattr_entry *last = entry;
1086 int new_offs;
1087
1088 /* Adjust the value offsets of the entries */
1089 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1090 if (!last->e_value_block && last->e_value_size) {
1091 new_offs = le16_to_cpu(last->e_value_offs) +
1092 value_offs_shift;
1093 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1094 > blocksize);
1095 last->e_value_offs = cpu_to_le16(new_offs);
1096 }
1097 }
1098 /* Shift the entries by n bytes */
1099 memmove(to, from, n);
1100 }
1101
1102 /*
1103 * Expand an inode by new_extra_isize bytes when EAs are present.
1104 * Returns 0 on success or negative error number on failure.
1105 */
1106 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1107 struct ext4_inode *raw_inode, handle_t *handle)
1108 {
1109 struct ext4_xattr_ibody_header *header;
1110 struct ext4_xattr_entry *entry, *last, *first;
1111 struct buffer_head *bh = NULL;
1112 struct ext4_xattr_ibody_find *is = NULL;
1113 struct ext4_xattr_block_find *bs = NULL;
1114 char *buffer = NULL, *b_entry_name = NULL;
1115 size_t min_offs, free;
1116 int total_ino, total_blk;
1117 void *base, *start, *end;
1118 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1119 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1120
1121 down_write(&EXT4_I(inode)->xattr_sem);
1122 retry:
1123 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1124 up_write(&EXT4_I(inode)->xattr_sem);
1125 return 0;
1126 }
1127
1128 header = IHDR(inode, raw_inode);
1129 entry = IFIRST(header);
1130
1131 /*
1132 * Check if enough free space is available in the inode to shift the
1133 * entries ahead by new_extra_isize.
1134 */
1135
1136 base = start = entry;
1137 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1138 min_offs = end - base;
1139 last = entry;
1140 total_ino = sizeof(struct ext4_xattr_ibody_header);
1141
1142 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1143 if (free >= new_extra_isize) {
1144 entry = IFIRST(header);
1145 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1146 - new_extra_isize, (void *)raw_inode +
1147 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1148 (void *)header, total_ino,
1149 inode->i_sb->s_blocksize);
1150 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1151 error = 0;
1152 goto cleanup;
1153 }
1154
1155 /*
1156 * Enough free space isn't available in the inode, check if
1157 * EA block can hold new_extra_isize bytes.
1158 */
1159 if (EXT4_I(inode)->i_file_acl) {
1160 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1161 error = -EIO;
1162 if (!bh)
1163 goto cleanup;
1164 if (ext4_xattr_check_block(bh)) {
1165 ext4_error(inode->i_sb, __FUNCTION__,
1166 "inode %lu: bad block %llu", inode->i_ino,
1167 EXT4_I(inode)->i_file_acl);
1168 error = -EIO;
1169 goto cleanup;
1170 }
1171 base = BHDR(bh);
1172 first = BFIRST(bh);
1173 end = bh->b_data + bh->b_size;
1174 min_offs = end - base;
1175 free = ext4_xattr_free_space(first, &min_offs, base,
1176 &total_blk);
1177 if (free < new_extra_isize) {
1178 if (!tried_min_extra_isize && s_min_extra_isize) {
1179 tried_min_extra_isize++;
1180 new_extra_isize = s_min_extra_isize;
1181 brelse(bh);
1182 goto retry;
1183 }
1184 error = -1;
1185 goto cleanup;
1186 }
1187 } else {
1188 free = inode->i_sb->s_blocksize;
1189 }
1190
1191 while (new_extra_isize > 0) {
1192 size_t offs, size, entry_size;
1193 struct ext4_xattr_entry *small_entry = NULL;
1194 struct ext4_xattr_info i = {
1195 .value = NULL,
1196 .value_len = 0,
1197 };
1198 unsigned int total_size; /* EA entry size + value size */
1199 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1200 unsigned int min_total_size = ~0U;
1201
1202 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1203 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1204 if (!is || !bs) {
1205 error = -ENOMEM;
1206 goto cleanup;
1207 }
1208
1209 is->s.not_found = -ENODATA;
1210 bs->s.not_found = -ENODATA;
1211 is->iloc.bh = NULL;
1212 bs->bh = NULL;
1213
1214 last = IFIRST(header);
1215 /* Find the entry best suited to be pushed into EA block */
1216 entry = NULL;
1217 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1218 total_size =
1219 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1220 EXT4_XATTR_LEN(last->e_name_len);
1221 if (total_size <= free && total_size < min_total_size) {
1222 if (total_size < new_extra_isize) {
1223 small_entry = last;
1224 } else {
1225 entry = last;
1226 min_total_size = total_size;
1227 }
1228 }
1229 }
1230
1231 if (entry == NULL) {
1232 if (small_entry) {
1233 entry = small_entry;
1234 } else {
1235 if (!tried_min_extra_isize &&
1236 s_min_extra_isize) {
1237 tried_min_extra_isize++;
1238 new_extra_isize = s_min_extra_isize;
1239 goto retry;
1240 }
1241 error = -1;
1242 goto cleanup;
1243 }
1244 }
1245 offs = le16_to_cpu(entry->e_value_offs);
1246 size = le32_to_cpu(entry->e_value_size);
1247 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1248 i.name_index = entry->e_name_index,
1249 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1250 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1251 if (!buffer || !b_entry_name) {
1252 error = -ENOMEM;
1253 goto cleanup;
1254 }
1255 /* Save the entry name and the entry value */
1256 memcpy(buffer, (void *)IFIRST(header) + offs,
1257 EXT4_XATTR_SIZE(size));
1258 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1259 b_entry_name[entry->e_name_len] = '\0';
1260 i.name = b_entry_name;
1261
1262 error = ext4_get_inode_loc(inode, &is->iloc);
1263 if (error)
1264 goto cleanup;
1265
1266 error = ext4_xattr_ibody_find(inode, &i, is);
1267 if (error)
1268 goto cleanup;
1269
1270 /* Remove the chosen entry from the inode */
1271 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1272
1273 entry = IFIRST(header);
1274 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1275 shift_bytes = new_extra_isize;
1276 else
1277 shift_bytes = entry_size + size;
1278 /* Adjust the offsets and shift the remaining entries ahead */
1279 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1280 shift_bytes, (void *)raw_inode +
1281 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1282 (void *)header, total_ino - entry_size,
1283 inode->i_sb->s_blocksize);
1284
1285 extra_isize += shift_bytes;
1286 new_extra_isize -= shift_bytes;
1287 EXT4_I(inode)->i_extra_isize = extra_isize;
1288
1289 i.name = b_entry_name;
1290 i.value = buffer;
1291 i.value_len = size;
1292 error = ext4_xattr_block_find(inode, &i, bs);
1293 if (error)
1294 goto cleanup;
1295
1296 /* Add entry which was removed from the inode into the block */
1297 error = ext4_xattr_block_set(handle, inode, &i, bs);
1298 if (error)
1299 goto cleanup;
1300 kfree(b_entry_name);
1301 kfree(buffer);
1302 brelse(is->iloc.bh);
1303 kfree(is);
1304 kfree(bs);
1305 }
1306 brelse(bh);
1307 up_write(&EXT4_I(inode)->xattr_sem);
1308 return 0;
1309
1310 cleanup:
1311 kfree(b_entry_name);
1312 kfree(buffer);
1313 if (is)
1314 brelse(is->iloc.bh);
1315 kfree(is);
1316 kfree(bs);
1317 brelse(bh);
1318 up_write(&EXT4_I(inode)->xattr_sem);
1319 return error;
1320 }
1321
1322
1323
1324 /*
1325 * ext4_xattr_delete_inode()
1326 *
1327 * Free extended attribute resources associated with this inode. This
1328 * is called immediately before an inode is freed. We have exclusive
1329 * access to the inode.
1330 */
1331 void
1332 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1333 {
1334 struct buffer_head *bh = NULL;
1335
1336 if (!EXT4_I(inode)->i_file_acl)
1337 goto cleanup;
1338 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1339 if (!bh) {
1340 ext4_error(inode->i_sb, __FUNCTION__,
1341 "inode %lu: block %llu read error", inode->i_ino,
1342 EXT4_I(inode)->i_file_acl);
1343 goto cleanup;
1344 }
1345 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1346 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1347 ext4_error(inode->i_sb, __FUNCTION__,
1348 "inode %lu: bad block %llu", inode->i_ino,
1349 EXT4_I(inode)->i_file_acl);
1350 goto cleanup;
1351 }
1352 ext4_xattr_release_block(handle, inode, bh);
1353 EXT4_I(inode)->i_file_acl = 0;
1354
1355 cleanup:
1356 brelse(bh);
1357 }
1358
1359 /*
1360 * ext4_xattr_put_super()
1361 *
1362 * This is called when a file system is unmounted.
1363 */
1364 void
1365 ext4_xattr_put_super(struct super_block *sb)
1366 {
1367 mb_cache_shrink(sb->s_bdev);
1368 }
1369
1370 /*
1371 * ext4_xattr_cache_insert()
1372 *
1373 * Create a new entry in the extended attribute cache, and insert
1374 * it unless such an entry is already in the cache.
1375 *
1376 * Returns 0, or a negative error number on failure.
1377 */
1378 static void
1379 ext4_xattr_cache_insert(struct buffer_head *bh)
1380 {
1381 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1382 struct mb_cache_entry *ce;
1383 int error;
1384
1385 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1386 if (!ce) {
1387 ea_bdebug(bh, "out of memory");
1388 return;
1389 }
1390 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1391 if (error) {
1392 mb_cache_entry_free(ce);
1393 if (error == -EBUSY) {
1394 ea_bdebug(bh, "already in cache");
1395 error = 0;
1396 }
1397 } else {
1398 ea_bdebug(bh, "inserting [%x]", (int)hash);
1399 mb_cache_entry_release(ce);
1400 }
1401 }
1402
1403 /*
1404 * ext4_xattr_cmp()
1405 *
1406 * Compare two extended attribute blocks for equality.
1407 *
1408 * Returns 0 if the blocks are equal, 1 if they differ, and
1409 * a negative error number on errors.
1410 */
1411 static int
1412 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1413 struct ext4_xattr_header *header2)
1414 {
1415 struct ext4_xattr_entry *entry1, *entry2;
1416
1417 entry1 = ENTRY(header1+1);
1418 entry2 = ENTRY(header2+1);
1419 while (!IS_LAST_ENTRY(entry1)) {
1420 if (IS_LAST_ENTRY(entry2))
1421 return 1;
1422 if (entry1->e_hash != entry2->e_hash ||
1423 entry1->e_name_index != entry2->e_name_index ||
1424 entry1->e_name_len != entry2->e_name_len ||
1425 entry1->e_value_size != entry2->e_value_size ||
1426 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1427 return 1;
1428 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1429 return -EIO;
1430 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1431 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1432 le32_to_cpu(entry1->e_value_size)))
1433 return 1;
1434
1435 entry1 = EXT4_XATTR_NEXT(entry1);
1436 entry2 = EXT4_XATTR_NEXT(entry2);
1437 }
1438 if (!IS_LAST_ENTRY(entry2))
1439 return 1;
1440 return 0;
1441 }
1442
1443 /*
1444 * ext4_xattr_cache_find()
1445 *
1446 * Find an identical extended attribute block.
1447 *
1448 * Returns a pointer to the block found, or NULL if such a block was
1449 * not found or an error occurred.
1450 */
1451 static struct buffer_head *
1452 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1453 struct mb_cache_entry **pce)
1454 {
1455 __u32 hash = le32_to_cpu(header->h_hash);
1456 struct mb_cache_entry *ce;
1457
1458 if (!header->h_hash)
1459 return NULL; /* never share */
1460 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1461 again:
1462 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1463 inode->i_sb->s_bdev, hash);
1464 while (ce) {
1465 struct buffer_head *bh;
1466
1467 if (IS_ERR(ce)) {
1468 if (PTR_ERR(ce) == -EAGAIN)
1469 goto again;
1470 break;
1471 }
1472 bh = sb_bread(inode->i_sb, ce->e_block);
1473 if (!bh) {
1474 ext4_error(inode->i_sb, __FUNCTION__,
1475 "inode %lu: block %lu read error",
1476 inode->i_ino, (unsigned long) ce->e_block);
1477 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1478 EXT4_XATTR_REFCOUNT_MAX) {
1479 ea_idebug(inode, "block %lu refcount %d>=%d",
1480 (unsigned long) ce->e_block,
1481 le32_to_cpu(BHDR(bh)->h_refcount),
1482 EXT4_XATTR_REFCOUNT_MAX);
1483 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1484 *pce = ce;
1485 return bh;
1486 }
1487 brelse(bh);
1488 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1489 }
1490 return NULL;
1491 }
1492
1493 #define NAME_HASH_SHIFT 5
1494 #define VALUE_HASH_SHIFT 16
1495
1496 /*
1497 * ext4_xattr_hash_entry()
1498 *
1499 * Compute the hash of an extended attribute.
1500 */
1501 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1502 struct ext4_xattr_entry *entry)
1503 {
1504 __u32 hash = 0;
1505 char *name = entry->e_name;
1506 int n;
1507
1508 for (n=0; n < entry->e_name_len; n++) {
1509 hash = (hash << NAME_HASH_SHIFT) ^
1510 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1511 *name++;
1512 }
1513
1514 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1515 __le32 *value = (__le32 *)((char *)header +
1516 le16_to_cpu(entry->e_value_offs));
1517 for (n = (le32_to_cpu(entry->e_value_size) +
1518 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1519 hash = (hash << VALUE_HASH_SHIFT) ^
1520 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1521 le32_to_cpu(*value++);
1522 }
1523 }
1524 entry->e_hash = cpu_to_le32(hash);
1525 }
1526
1527 #undef NAME_HASH_SHIFT
1528 #undef VALUE_HASH_SHIFT
1529
1530 #define BLOCK_HASH_SHIFT 16
1531
1532 /*
1533 * ext4_xattr_rehash()
1534 *
1535 * Re-compute the extended attribute hash value after an entry has changed.
1536 */
1537 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1538 struct ext4_xattr_entry *entry)
1539 {
1540 struct ext4_xattr_entry *here;
1541 __u32 hash = 0;
1542
1543 ext4_xattr_hash_entry(header, entry);
1544 here = ENTRY(header+1);
1545 while (!IS_LAST_ENTRY(here)) {
1546 if (!here->e_hash) {
1547 /* Block is not shared if an entry's hash value == 0 */
1548 hash = 0;
1549 break;
1550 }
1551 hash = (hash << BLOCK_HASH_SHIFT) ^
1552 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1553 le32_to_cpu(here->e_hash);
1554 here = EXT4_XATTR_NEXT(here);
1555 }
1556 header->h_hash = cpu_to_le32(hash);
1557 }
1558
1559 #undef BLOCK_HASH_SHIFT
1560
1561 int __init
1562 init_ext4_xattr(void)
1563 {
1564 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1565 sizeof(struct mb_cache_entry) +
1566 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1567 if (!ext4_xattr_cache)
1568 return -ENOMEM;
1569 return 0;
1570 }
1571
1572 void
1573 exit_ext4_xattr(void)
1574 {
1575 if (ext4_xattr_cache)
1576 mb_cache_destroy(ext4_xattr_cache);
1577 ext4_xattr_cache = NULL;
1578 }
kmemtrace - Kernel memory tracer