projects / deliverable / linux.git / blob
? search:


1bff752d1b596616548ed00e9939542739f2ddbb
[deliverable/linux.git] / fs / ext4 / xattr.c
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/mbcache.h>
57 #include <linux/quotaops.h>
58 #include <linux/rwsem.h>
59 #include "ext4_jbd2.h"
60 #include "ext4.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 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
96 size_t buffer_size);
97
98 static struct mb_cache *ext4_xattr_cache;
99
100 static const struct xattr_handler *ext4_xattr_handler_map[] = {
101 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
103 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
104 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
105 #endif
106 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
107 #ifdef CONFIG_EXT4_FS_SECURITY
108 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
109 #endif
110 };
111
112 const struct xattr_handler *ext4_xattr_handlers[] = {
113 &ext4_xattr_user_handler,
114 &ext4_xattr_trusted_handler,
115 #ifdef CONFIG_EXT4_FS_POSIX_ACL
116 &ext4_xattr_acl_access_handler,
117 &ext4_xattr_acl_default_handler,
118 #endif
119 #ifdef CONFIG_EXT4_FS_SECURITY
120 &ext4_xattr_security_handler,
121 #endif
122 NULL
123 };
124
125 static inline const struct xattr_handler *
126 ext4_xattr_handler(int name_index)
127 {
128 const struct xattr_handler *handler = NULL;
129
130 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
131 handler = ext4_xattr_handler_map[name_index];
132 return handler;
133 }
134
135 /*
136 * Inode operation listxattr()
137 *
138 * dentry->d_inode->i_mutex: don't care
139 */
140 ssize_t
141 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
142 {
143 return ext4_xattr_list(dentry, buffer, size);
144 }
145
146 static int
147 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
148 {
149 while (!IS_LAST_ENTRY(entry)) {
150 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
151 if ((void *)next >= end)
152 return -EIO;
153 entry = next;
154 }
155 return 0;
156 }
157
158 static inline int
159 ext4_xattr_check_block(struct buffer_head *bh)
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 return ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
165 }
166
167 static inline int
168 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
169 {
170 size_t value_size = le32_to_cpu(entry->e_value_size);
171
172 if (entry->e_value_block != 0 || value_size > size ||
173 le16_to_cpu(entry->e_value_offs) + value_size > size)
174 return -EIO;
175 return 0;
176 }
177
178 static int
179 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
180 const char *name, size_t size, int sorted)
181 {
182 struct ext4_xattr_entry *entry;
183 size_t name_len;
184 int cmp = 1;
185
186 if (name == NULL)
187 return -EINVAL;
188 name_len = strlen(name);
189 entry = *pentry;
190 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
191 cmp = name_index - entry->e_name_index;
192 if (!cmp)
193 cmp = name_len - entry->e_name_len;
194 if (!cmp)
195 cmp = memcmp(name, entry->e_name, name_len);
196 if (cmp <= 0 && (sorted || cmp == 0))
197 break;
198 }
199 *pentry = entry;
200 if (!cmp && ext4_xattr_check_entry(entry, size))
201 return -EIO;
202 return cmp ? -ENODATA : 0;
203 }
204
205 static int
206 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
207 void *buffer, size_t buffer_size)
208 {
209 struct buffer_head *bh = NULL;
210 struct ext4_xattr_entry *entry;
211 size_t size;
212 int error;
213
214 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
215 name_index, name, buffer, (long)buffer_size);
216
217 error = -ENODATA;
218 if (!EXT4_I(inode)->i_file_acl)
219 goto cleanup;
220 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
221 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
222 if (!bh)
223 goto cleanup;
224 ea_bdebug(bh, "b_count=%d, refcount=%d",
225 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
226 if (ext4_xattr_check_block(bh)) {
227 bad_block:
228 EXT4_ERROR_INODE(inode, "bad block %llu",
229 EXT4_I(inode)->i_file_acl);
230 error = -EIO;
231 goto cleanup;
232 }
233 ext4_xattr_cache_insert(bh);
234 entry = BFIRST(bh);
235 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
236 if (error == -EIO)
237 goto bad_block;
238 if (error)
239 goto cleanup;
240 size = le32_to_cpu(entry->e_value_size);
241 if (buffer) {
242 error = -ERANGE;
243 if (size > buffer_size)
244 goto cleanup;
245 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
246 size);
247 }
248 error = size;
249
250 cleanup:
251 brelse(bh);
252 return error;
253 }
254
255 static int
256 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
257 void *buffer, size_t buffer_size)
258 {
259 struct ext4_xattr_ibody_header *header;
260 struct ext4_xattr_entry *entry;
261 struct ext4_inode *raw_inode;
262 struct ext4_iloc iloc;
263 size_t size;
264 void *end;
265 int error;
266
267 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
268 return -ENODATA;
269 error = ext4_get_inode_loc(inode, &iloc);
270 if (error)
271 return error;
272 raw_inode = ext4_raw_inode(&iloc);
273 header = IHDR(inode, raw_inode);
274 entry = IFIRST(header);
275 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
276 error = ext4_xattr_check_names(entry, end);
277 if (error)
278 goto cleanup;
279 error = ext4_xattr_find_entry(&entry, name_index, name,
280 end - (void *)entry, 0);
281 if (error)
282 goto cleanup;
283 size = le32_to_cpu(entry->e_value_size);
284 if (buffer) {
285 error = -ERANGE;
286 if (size > buffer_size)
287 goto cleanup;
288 memcpy(buffer, (void *)IFIRST(header) +
289 le16_to_cpu(entry->e_value_offs), size);
290 }
291 error = size;
292
293 cleanup:
294 brelse(iloc.bh);
295 return error;
296 }
297
298 /*
299 * ext4_xattr_get()
300 *
301 * Copy an extended attribute into the buffer
302 * provided, or compute the buffer size required.
303 * Buffer is NULL to compute the size of the buffer required.
304 *
305 * Returns a negative error number on failure, or the number of bytes
306 * used / required on success.
307 */
308 int
309 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
310 void *buffer, size_t buffer_size)
311 {
312 int error;
313
314 down_read(&EXT4_I(inode)->xattr_sem);
315 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
316 buffer_size);
317 if (error == -ENODATA)
318 error = ext4_xattr_block_get(inode, name_index, name, buffer,
319 buffer_size);
320 up_read(&EXT4_I(inode)->xattr_sem);
321 return error;
322 }
323
324 static int
325 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
326 char *buffer, size_t buffer_size)
327 {
328 size_t rest = buffer_size;
329
330 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
331 const struct xattr_handler *handler =
332 ext4_xattr_handler(entry->e_name_index);
333
334 if (handler) {
335 size_t size = handler->list(dentry, buffer, rest,
336 entry->e_name,
337 entry->e_name_len,
338 handler->flags);
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 dentry *dentry, char *buffer, size_t buffer_size)
352 {
353 struct inode *inode = dentry->d_inode;
354 struct buffer_head *bh = NULL;
355 int error;
356
357 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
358 buffer, (long)buffer_size);
359
360 error = 0;
361 if (!EXT4_I(inode)->i_file_acl)
362 goto cleanup;
363 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
364 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
365 error = -EIO;
366 if (!bh)
367 goto cleanup;
368 ea_bdebug(bh, "b_count=%d, refcount=%d",
369 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
370 if (ext4_xattr_check_block(bh)) {
371 EXT4_ERROR_INODE(inode, "bad block %llu",
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(dentry, 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 dentry *dentry, char *buffer, size_t buffer_size)
387 {
388 struct inode *inode = dentry->d_inode;
389 struct ext4_xattr_ibody_header *header;
390 struct ext4_inode *raw_inode;
391 struct ext4_iloc iloc;
392 void *end;
393 int error;
394
395 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
396 return 0;
397 error = ext4_get_inode_loc(inode, &iloc);
398 if (error)
399 return error;
400 raw_inode = ext4_raw_inode(&iloc);
401 header = IHDR(inode, raw_inode);
402 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
403 error = ext4_xattr_check_names(IFIRST(header), end);
404 if (error)
405 goto cleanup;
406 error = ext4_xattr_list_entries(dentry, IFIRST(header),
407 buffer, buffer_size);
408
409 cleanup:
410 brelse(iloc.bh);
411 return error;
412 }
413
414 /*
415 * ext4_xattr_list()
416 *
417 * Copy a list of attribute names into the buffer
418 * provided, or compute the buffer size required.
419 * Buffer is NULL to compute the size of the buffer required.
420 *
421 * Returns a negative error number on failure, or the number of bytes
422 * used / required on success.
423 */
424 static int
425 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
426 {
427 int ret, ret2;
428
429 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
430 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
431 if (ret < 0)
432 goto errout;
433 if (buffer) {
434 buffer += ret;
435 buffer_size -= ret;
436 }
437 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
438 if (ret < 0)
439 goto errout;
440 ret += ret2;
441 errout:
442 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
443 return ret;
444 }
445
446 /*
447 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
448 * not set, set it.
449 */
450 static void ext4_xattr_update_super_block(handle_t *handle,
451 struct super_block *sb)
452 {
453 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
454 return;
455
456 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
457 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
458 ext4_handle_dirty_super(handle, sb);
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 get_bh(bh);
484 ext4_free_blocks(handle, inode, bh, 0, 1,
485 EXT4_FREE_BLOCKS_METADATA |
486 EXT4_FREE_BLOCKS_FORGET);
487 } else {
488 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
489 error = ext4_handle_dirty_metadata(handle, inode, bh);
490 if (IS_SYNC(inode))
491 ext4_handle_sync(handle);
492 dquot_free_block(inode, 1);
493 ea_bdebug(bh, "refcount now=%d; releasing",
494 le32_to_cpu(BHDR(bh)->h_refcount));
495 if (ce)
496 mb_cache_entry_release(ce);
497 }
498 unlock_buffer(bh);
499 out:
500 ext4_std_error(inode->i_sb, error);
501 return;
502 }
503
504 /*
505 * Find the available free space for EAs. This also returns the total number of
506 * bytes used by EA entries.
507 */
508 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
509 size_t *min_offs, void *base, int *total)
510 {
511 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
512 *total += EXT4_XATTR_LEN(last->e_name_len);
513 if (!last->e_value_block && last->e_value_size) {
514 size_t offs = le16_to_cpu(last->e_value_offs);
515 if (offs < *min_offs)
516 *min_offs = offs;
517 }
518 }
519 return (*min_offs - ((void *)last - base) - sizeof(__u32));
520 }
521
522 struct ext4_xattr_info {
523 int name_index;
524 const char *name;
525 const void *value;
526 size_t value_len;
527 };
528
529 struct ext4_xattr_search {
530 struct ext4_xattr_entry *first;
531 void *base;
532 void *end;
533 struct ext4_xattr_entry *here;
534 int not_found;
535 };
536
537 static int
538 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
539 {
540 struct ext4_xattr_entry *last;
541 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
542
543 /* Compute min_offs and last. */
544 last = s->first;
545 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
546 if (!last->e_value_block && last->e_value_size) {
547 size_t offs = le16_to_cpu(last->e_value_offs);
548 if (offs < min_offs)
549 min_offs = offs;
550 }
551 }
552 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
553 if (!s->not_found) {
554 if (!s->here->e_value_block && s->here->e_value_size) {
555 size_t size = le32_to_cpu(s->here->e_value_size);
556 free += EXT4_XATTR_SIZE(size);
557 }
558 free += EXT4_XATTR_LEN(name_len);
559 }
560 if (i->value) {
561 if (free < EXT4_XATTR_SIZE(i->value_len) ||
562 free < EXT4_XATTR_LEN(name_len) +
563 EXT4_XATTR_SIZE(i->value_len))
564 return -ENOSPC;
565 }
566
567 if (i->value && s->not_found) {
568 /* Insert the new name. */
569 size_t size = EXT4_XATTR_LEN(name_len);
570 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
571 memmove((void *)s->here + size, s->here, rest);
572 memset(s->here, 0, size);
573 s->here->e_name_index = i->name_index;
574 s->here->e_name_len = name_len;
575 memcpy(s->here->e_name, i->name, name_len);
576 } else {
577 if (!s->here->e_value_block && s->here->e_value_size) {
578 void *first_val = s->base + min_offs;
579 size_t offs = le16_to_cpu(s->here->e_value_offs);
580 void *val = s->base + offs;
581 size_t size = EXT4_XATTR_SIZE(
582 le32_to_cpu(s->here->e_value_size));
583
584 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
585 /* The old and the new value have the same
586 size. Just replace. */
587 s->here->e_value_size =
588 cpu_to_le32(i->value_len);
589 memset(val + size - EXT4_XATTR_PAD, 0,
590 EXT4_XATTR_PAD); /* Clear pad bytes. */
591 memcpy(val, i->value, i->value_len);
592 return 0;
593 }
594
595 /* Remove the old value. */
596 memmove(first_val + size, first_val, val - first_val);
597 memset(first_val, 0, size);
598 s->here->e_value_size = 0;
599 s->here->e_value_offs = 0;
600 min_offs += size;
601
602 /* Adjust all value offsets. */
603 last = s->first;
604 while (!IS_LAST_ENTRY(last)) {
605 size_t o = le16_to_cpu(last->e_value_offs);
606 if (!last->e_value_block &&
607 last->e_value_size && o < offs)
608 last->e_value_offs =
609 cpu_to_le16(o + size);
610 last = EXT4_XATTR_NEXT(last);
611 }
612 }
613 if (!i->value) {
614 /* Remove the old name. */
615 size_t size = EXT4_XATTR_LEN(name_len);
616 last = ENTRY((void *)last - size);
617 memmove(s->here, (void *)s->here + size,
618 (void *)last - (void *)s->here + sizeof(__u32));
619 memset(last, 0, size);
620 }
621 }
622
623 if (i->value) {
624 /* Insert the new value. */
625 s->here->e_value_size = cpu_to_le32(i->value_len);
626 if (i->value_len) {
627 size_t size = EXT4_XATTR_SIZE(i->value_len);
628 void *val = s->base + min_offs - size;
629 s->here->e_value_offs = cpu_to_le16(min_offs - size);
630 memset(val + size - EXT4_XATTR_PAD, 0,
631 EXT4_XATTR_PAD); /* Clear the pad bytes. */
632 memcpy(val, i->value, i->value_len);
633 }
634 }
635 return 0;
636 }
637
638 struct ext4_xattr_block_find {
639 struct ext4_xattr_search s;
640 struct buffer_head *bh;
641 };
642
643 static int
644 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
645 struct ext4_xattr_block_find *bs)
646 {
647 struct super_block *sb = inode->i_sb;
648 int error;
649
650 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
651 i->name_index, i->name, i->value, (long)i->value_len);
652
653 if (EXT4_I(inode)->i_file_acl) {
654 /* The inode already has an extended attribute block. */
655 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
656 error = -EIO;
657 if (!bs->bh)
658 goto cleanup;
659 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
660 atomic_read(&(bs->bh->b_count)),
661 le32_to_cpu(BHDR(bs->bh)->h_refcount));
662 if (ext4_xattr_check_block(bs->bh)) {
663 EXT4_ERROR_INODE(inode, "bad block %llu",
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_handle_dirty_metadata(handle,
726 inode,
727 bs->bh);
728 if (error)
729 goto cleanup;
730 goto inserted;
731 } else {
732 int offset = (char *)s->here - bs->bh->b_data;
733
734 unlock_buffer(bs->bh);
735 ext4_handle_release_buffer(handle, bs->bh);
736 if (ce) {
737 mb_cache_entry_release(ce);
738 ce = NULL;
739 }
740 ea_bdebug(bs->bh, "cloning");
741 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
742 error = -ENOMEM;
743 if (s->base == NULL)
744 goto cleanup;
745 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
746 s->first = ENTRY(header(s->base)+1);
747 header(s->base)->h_refcount = cpu_to_le32(1);
748 s->here = ENTRY(s->base + offset);
749 s->end = s->base + bs->bh->b_size;
750 }
751 } else {
752 /* Allocate a buffer where we construct the new block. */
753 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
754 /* assert(header == s->base) */
755 error = -ENOMEM;
756 if (s->base == NULL)
757 goto cleanup;
758 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
759 header(s->base)->h_blocks = cpu_to_le32(1);
760 header(s->base)->h_refcount = cpu_to_le32(1);
761 s->first = ENTRY(header(s->base)+1);
762 s->here = ENTRY(header(s->base)+1);
763 s->end = s->base + sb->s_blocksize;
764 }
765
766 error = ext4_xattr_set_entry(i, s);
767 if (error == -EIO)
768 goto bad_block;
769 if (error)
770 goto cleanup;
771 if (!IS_LAST_ENTRY(s->first))
772 ext4_xattr_rehash(header(s->base), s->here);
773
774 inserted:
775 if (!IS_LAST_ENTRY(s->first)) {
776 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
777 if (new_bh) {
778 /* We found an identical block in the cache. */
779 if (new_bh == bs->bh)
780 ea_bdebug(new_bh, "keeping");
781 else {
782 /* The old block is released after updating
783 the inode. */
784 error = dquot_alloc_block(inode, 1);
785 if (error)
786 goto cleanup;
787 error = ext4_journal_get_write_access(handle,
788 new_bh);
789 if (error)
790 goto cleanup_dquot;
791 lock_buffer(new_bh);
792 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
793 ea_bdebug(new_bh, "reusing; refcount now=%d",
794 le32_to_cpu(BHDR(new_bh)->h_refcount));
795 unlock_buffer(new_bh);
796 error = ext4_handle_dirty_metadata(handle,
797 inode,
798 new_bh);
799 if (error)
800 goto cleanup_dquot;
801 }
802 mb_cache_entry_release(ce);
803 ce = NULL;
804 } else if (bs->bh && s->base == bs->bh->b_data) {
805 /* We were modifying this block in-place. */
806 ea_bdebug(bs->bh, "keeping this block");
807 new_bh = bs->bh;
808 get_bh(new_bh);
809 } else {
810 /* We need to allocate a new block */
811 ext4_fsblk_t goal, block;
812
813 goal = ext4_group_first_block_no(sb,
814 EXT4_I(inode)->i_block_group);
815
816 /* non-extent files can't have physical blocks past 2^32 */
817 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
818 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
819
820 /*
821 * take i_data_sem because we will test
822 * i_delalloc_reserved_flag in ext4_mb_new_blocks
823 */
824 down_read((&EXT4_I(inode)->i_data_sem));
825 block = ext4_new_meta_blocks(handle, inode, goal, 0,
826 NULL, &error);
827 up_read((&EXT4_I(inode)->i_data_sem));
828 if (error)
829 goto cleanup;
830
831 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
832 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
833
834 ea_idebug(inode, "creating block %d", block);
835
836 new_bh = sb_getblk(sb, block);
837 if (!new_bh) {
838 getblk_failed:
839 ext4_free_blocks(handle, inode, NULL, block, 1,
840 EXT4_FREE_BLOCKS_METADATA);
841 error = -EIO;
842 goto cleanup;
843 }
844 lock_buffer(new_bh);
845 error = ext4_journal_get_create_access(handle, new_bh);
846 if (error) {
847 unlock_buffer(new_bh);
848 goto getblk_failed;
849 }
850 memcpy(new_bh->b_data, s->base, new_bh->b_size);
851 set_buffer_uptodate(new_bh);
852 unlock_buffer(new_bh);
853 ext4_xattr_cache_insert(new_bh);
854 error = ext4_handle_dirty_metadata(handle,
855 inode, new_bh);
856 if (error)
857 goto cleanup;
858 }
859 }
860
861 /* Update the inode. */
862 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
863
864 /* Drop the previous xattr block. */
865 if (bs->bh && bs->bh != new_bh)
866 ext4_xattr_release_block(handle, inode, bs->bh);
867 error = 0;
868
869 cleanup:
870 if (ce)
871 mb_cache_entry_release(ce);
872 brelse(new_bh);
873 if (!(bs->bh && s->base == bs->bh->b_data))
874 kfree(s->base);
875
876 return error;
877
878 cleanup_dquot:
879 dquot_free_block(inode, 1);
880 goto cleanup;
881
882 bad_block:
883 EXT4_ERROR_INODE(inode, "bad block %llu",
884 EXT4_I(inode)->i_file_acl);
885 goto cleanup;
886
887 #undef header
888 }
889
890 struct ext4_xattr_ibody_find {
891 struct ext4_xattr_search s;
892 struct ext4_iloc iloc;
893 };
894
895 static int
896 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
897 struct ext4_xattr_ibody_find *is)
898 {
899 struct ext4_xattr_ibody_header *header;
900 struct ext4_inode *raw_inode;
901 int error;
902
903 if (EXT4_I(inode)->i_extra_isize == 0)
904 return 0;
905 raw_inode = ext4_raw_inode(&is->iloc);
906 header = IHDR(inode, raw_inode);
907 is->s.base = is->s.first = IFIRST(header);
908 is->s.here = is->s.first;
909 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
910 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
911 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
912 if (error)
913 return error;
914 /* Find the named attribute. */
915 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
916 i->name, is->s.end -
917 (void *)is->s.base, 0);
918 if (error && error != -ENODATA)
919 return error;
920 is->s.not_found = error;
921 }
922 return 0;
923 }
924
925 static int
926 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
927 struct ext4_xattr_info *i,
928 struct ext4_xattr_ibody_find *is)
929 {
930 struct ext4_xattr_ibody_header *header;
931 struct ext4_xattr_search *s = &is->s;
932 int error;
933
934 if (EXT4_I(inode)->i_extra_isize == 0)
935 return -ENOSPC;
936 error = ext4_xattr_set_entry(i, s);
937 if (error)
938 return error;
939 header = IHDR(inode, ext4_raw_inode(&is->iloc));
940 if (!IS_LAST_ENTRY(s->first)) {
941 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
942 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
943 } else {
944 header->h_magic = cpu_to_le32(0);
945 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
946 }
947 return 0;
948 }
949
950 /*
951 * ext4_xattr_set_handle()
952 *
953 * Create, replace or remove an extended attribute for this inode. Value
954 * is NULL to remove an existing extended attribute, and non-NULL to
955 * either replace an existing extended attribute, or create a new extended
956 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
957 * specify that an extended attribute must exist and must not exist
958 * previous to the call, respectively.
959 *
960 * Returns 0, or a negative error number on failure.
961 */
962 int
963 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
964 const char *name, const void *value, size_t value_len,
965 int flags)
966 {
967 struct ext4_xattr_info i = {
968 .name_index = name_index,
969 .name = name,
970 .value = value,
971 .value_len = value_len,
972
973 };
974 struct ext4_xattr_ibody_find is = {
975 .s = { .not_found = -ENODATA, },
976 };
977 struct ext4_xattr_block_find bs = {
978 .s = { .not_found = -ENODATA, },
979 };
980 unsigned long no_expand;
981 int error;
982
983 if (!name)
984 return -EINVAL;
985 if (strlen(name) > 255)
986 return -ERANGE;
987 down_write(&EXT4_I(inode)->xattr_sem);
988 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
989 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
990
991 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
992 if (error)
993 goto cleanup;
994
995 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
996 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
997 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
998 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
999 }
1000
1001 error = ext4_xattr_ibody_find(inode, &i, &is);
1002 if (error)
1003 goto cleanup;
1004 if (is.s.not_found)
1005 error = ext4_xattr_block_find(inode, &i, &bs);
1006 if (error)
1007 goto cleanup;
1008 if (is.s.not_found && bs.s.not_found) {
1009 error = -ENODATA;
1010 if (flags & XATTR_REPLACE)
1011 goto cleanup;
1012 error = 0;
1013 if (!value)
1014 goto cleanup;
1015 } else {
1016 error = -EEXIST;
1017 if (flags & XATTR_CREATE)
1018 goto cleanup;
1019 }
1020 if (!value) {
1021 if (!is.s.not_found)
1022 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1023 else if (!bs.s.not_found)
1024 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1025 } else {
1026 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1027 if (!error && !bs.s.not_found) {
1028 i.value = NULL;
1029 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1030 } else if (error == -ENOSPC) {
1031 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1032 error = ext4_xattr_block_find(inode, &i, &bs);
1033 if (error)
1034 goto cleanup;
1035 }
1036 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1037 if (error)
1038 goto cleanup;
1039 if (!is.s.not_found) {
1040 i.value = NULL;
1041 error = ext4_xattr_ibody_set(handle, inode, &i,
1042 &is);
1043 }
1044 }
1045 }
1046 if (!error) {
1047 ext4_xattr_update_super_block(handle, inode->i_sb);
1048 inode->i_ctime = ext4_current_time(inode);
1049 if (!value)
1050 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1051 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1052 /*
1053 * The bh is consumed by ext4_mark_iloc_dirty, even with
1054 * error != 0.
1055 */
1056 is.iloc.bh = NULL;
1057 if (IS_SYNC(inode))
1058 ext4_handle_sync(handle);
1059 }
1060
1061 cleanup:
1062 brelse(is.iloc.bh);
1063 brelse(bs.bh);
1064 if (no_expand == 0)
1065 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1066 up_write(&EXT4_I(inode)->xattr_sem);
1067 return error;
1068 }
1069
1070 /*
1071 * ext4_xattr_set()
1072 *
1073 * Like ext4_xattr_set_handle, but start from an inode. This extended
1074 * attribute modification is a filesystem transaction by itself.
1075 *
1076 * Returns 0, or a negative error number on failure.
1077 */
1078 int
1079 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1080 const void *value, size_t value_len, int flags)
1081 {
1082 handle_t *handle;
1083 int error, retries = 0;
1084
1085 retry:
1086 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1087 if (IS_ERR(handle)) {
1088 error = PTR_ERR(handle);
1089 } else {
1090 int error2;
1091
1092 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1093 value, value_len, flags);
1094 error2 = ext4_journal_stop(handle);
1095 if (error == -ENOSPC &&
1096 ext4_should_retry_alloc(inode->i_sb, &retries))
1097 goto retry;
1098 if (error == 0)
1099 error = error2;
1100 }
1101
1102 return error;
1103 }
1104
1105 /*
1106 * Shift the EA entries in the inode to create space for the increased
1107 * i_extra_isize.
1108 */
1109 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1110 int value_offs_shift, void *to,
1111 void *from, size_t n, int blocksize)
1112 {
1113 struct ext4_xattr_entry *last = entry;
1114 int new_offs;
1115
1116 /* Adjust the value offsets of the entries */
1117 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1118 if (!last->e_value_block && last->e_value_size) {
1119 new_offs = le16_to_cpu(last->e_value_offs) +
1120 value_offs_shift;
1121 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1122 > blocksize);
1123 last->e_value_offs = cpu_to_le16(new_offs);
1124 }
1125 }
1126 /* Shift the entries by n bytes */
1127 memmove(to, from, n);
1128 }
1129
1130 /*
1131 * Expand an inode by new_extra_isize bytes when EAs are present.
1132 * Returns 0 on success or negative error number on failure.
1133 */
1134 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1135 struct ext4_inode *raw_inode, handle_t *handle)
1136 {
1137 struct ext4_xattr_ibody_header *header;
1138 struct ext4_xattr_entry *entry, *last, *first;
1139 struct buffer_head *bh = NULL;
1140 struct ext4_xattr_ibody_find *is = NULL;
1141 struct ext4_xattr_block_find *bs = NULL;
1142 char *buffer = NULL, *b_entry_name = NULL;
1143 size_t min_offs, free;
1144 int total_ino, total_blk;
1145 void *base, *start, *end;
1146 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1147 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1148
1149 down_write(&EXT4_I(inode)->xattr_sem);
1150 retry:
1151 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1152 up_write(&EXT4_I(inode)->xattr_sem);
1153 return 0;
1154 }
1155
1156 header = IHDR(inode, raw_inode);
1157 entry = IFIRST(header);
1158
1159 /*
1160 * Check if enough free space is available in the inode to shift the
1161 * entries ahead by new_extra_isize.
1162 */
1163
1164 base = start = entry;
1165 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1166 min_offs = end - base;
1167 last = entry;
1168 total_ino = sizeof(struct ext4_xattr_ibody_header);
1169
1170 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1171 if (free >= new_extra_isize) {
1172 entry = IFIRST(header);
1173 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1174 - new_extra_isize, (void *)raw_inode +
1175 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1176 (void *)header, total_ino,
1177 inode->i_sb->s_blocksize);
1178 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1179 error = 0;
1180 goto cleanup;
1181 }
1182
1183 /*
1184 * Enough free space isn't available in the inode, check if
1185 * EA block can hold new_extra_isize bytes.
1186 */
1187 if (EXT4_I(inode)->i_file_acl) {
1188 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1189 error = -EIO;
1190 if (!bh)
1191 goto cleanup;
1192 if (ext4_xattr_check_block(bh)) {
1193 EXT4_ERROR_INODE(inode, "bad block %llu",
1194 EXT4_I(inode)->i_file_acl);
1195 error = -EIO;
1196 goto cleanup;
1197 }
1198 base = BHDR(bh);
1199 first = BFIRST(bh);
1200 end = bh->b_data + bh->b_size;
1201 min_offs = end - base;
1202 free = ext4_xattr_free_space(first, &min_offs, base,
1203 &total_blk);
1204 if (free < new_extra_isize) {
1205 if (!tried_min_extra_isize && s_min_extra_isize) {
1206 tried_min_extra_isize++;
1207 new_extra_isize = s_min_extra_isize;
1208 brelse(bh);
1209 goto retry;
1210 }
1211 error = -1;
1212 goto cleanup;
1213 }
1214 } else {
1215 free = inode->i_sb->s_blocksize;
1216 }
1217
1218 while (new_extra_isize > 0) {
1219 size_t offs, size, entry_size;
1220 struct ext4_xattr_entry *small_entry = NULL;
1221 struct ext4_xattr_info i = {
1222 .value = NULL,
1223 .value_len = 0,
1224 };
1225 unsigned int total_size; /* EA entry size + value size */
1226 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1227 unsigned int min_total_size = ~0U;
1228
1229 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1230 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1231 if (!is || !bs) {
1232 error = -ENOMEM;
1233 goto cleanup;
1234 }
1235
1236 is->s.not_found = -ENODATA;
1237 bs->s.not_found = -ENODATA;
1238 is->iloc.bh = NULL;
1239 bs->bh = NULL;
1240
1241 last = IFIRST(header);
1242 /* Find the entry best suited to be pushed into EA block */
1243 entry = NULL;
1244 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1245 total_size =
1246 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1247 EXT4_XATTR_LEN(last->e_name_len);
1248 if (total_size <= free && total_size < min_total_size) {
1249 if (total_size < new_extra_isize) {
1250 small_entry = last;
1251 } else {
1252 entry = last;
1253 min_total_size = total_size;
1254 }
1255 }
1256 }
1257
1258 if (entry == NULL) {
1259 if (small_entry) {
1260 entry = small_entry;
1261 } else {
1262 if (!tried_min_extra_isize &&
1263 s_min_extra_isize) {
1264 tried_min_extra_isize++;
1265 new_extra_isize = s_min_extra_isize;
1266 goto retry;
1267 }
1268 error = -1;
1269 goto cleanup;
1270 }
1271 }
1272 offs = le16_to_cpu(entry->e_value_offs);
1273 size = le32_to_cpu(entry->e_value_size);
1274 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1275 i.name_index = entry->e_name_index,
1276 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1277 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1278 if (!buffer || !b_entry_name) {
1279 error = -ENOMEM;
1280 goto cleanup;
1281 }
1282 /* Save the entry name and the entry value */
1283 memcpy(buffer, (void *)IFIRST(header) + offs,
1284 EXT4_XATTR_SIZE(size));
1285 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1286 b_entry_name[entry->e_name_len] = '\0';
1287 i.name = b_entry_name;
1288
1289 error = ext4_get_inode_loc(inode, &is->iloc);
1290 if (error)
1291 goto cleanup;
1292
1293 error = ext4_xattr_ibody_find(inode, &i, is);
1294 if (error)
1295 goto cleanup;
1296
1297 /* Remove the chosen entry from the inode */
1298 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1299 if (error)
1300 goto cleanup;
1301
1302 entry = IFIRST(header);
1303 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1304 shift_bytes = new_extra_isize;
1305 else
1306 shift_bytes = entry_size + size;
1307 /* Adjust the offsets and shift the remaining entries ahead */
1308 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1309 shift_bytes, (void *)raw_inode +
1310 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1311 (void *)header, total_ino - entry_size,
1312 inode->i_sb->s_blocksize);
1313
1314 extra_isize += shift_bytes;
1315 new_extra_isize -= shift_bytes;
1316 EXT4_I(inode)->i_extra_isize = extra_isize;
1317
1318 i.name = b_entry_name;
1319 i.value = buffer;
1320 i.value_len = size;
1321 error = ext4_xattr_block_find(inode, &i, bs);
1322 if (error)
1323 goto cleanup;
1324
1325 /* Add entry which was removed from the inode into the block */
1326 error = ext4_xattr_block_set(handle, inode, &i, bs);
1327 if (error)
1328 goto cleanup;
1329 kfree(b_entry_name);
1330 kfree(buffer);
1331 b_entry_name = NULL;
1332 buffer = NULL;
1333 brelse(is->iloc.bh);
1334 kfree(is);
1335 kfree(bs);
1336 }
1337 brelse(bh);
1338 up_write(&EXT4_I(inode)->xattr_sem);
1339 return 0;
1340
1341 cleanup:
1342 kfree(b_entry_name);
1343 kfree(buffer);
1344 if (is)
1345 brelse(is->iloc.bh);
1346 kfree(is);
1347 kfree(bs);
1348 brelse(bh);
1349 up_write(&EXT4_I(inode)->xattr_sem);
1350 return error;
1351 }
1352
1353
1354
1355 /*
1356 * ext4_xattr_delete_inode()
1357 *
1358 * Free extended attribute resources associated with this inode. This
1359 * is called immediately before an inode is freed. We have exclusive
1360 * access to the inode.
1361 */
1362 void
1363 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1364 {
1365 struct buffer_head *bh = NULL;
1366
1367 if (!EXT4_I(inode)->i_file_acl)
1368 goto cleanup;
1369 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1370 if (!bh) {
1371 EXT4_ERROR_INODE(inode, "block %llu read error",
1372 EXT4_I(inode)->i_file_acl);
1373 goto cleanup;
1374 }
1375 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1376 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1377 EXT4_ERROR_INODE(inode, "bad block %llu",
1378 EXT4_I(inode)->i_file_acl);
1379 goto cleanup;
1380 }
1381 ext4_xattr_release_block(handle, inode, bh);
1382 EXT4_I(inode)->i_file_acl = 0;
1383
1384 cleanup:
1385 brelse(bh);
1386 }
1387
1388 /*
1389 * ext4_xattr_put_super()
1390 *
1391 * This is called when a file system is unmounted.
1392 */
1393 void
1394 ext4_xattr_put_super(struct super_block *sb)
1395 {
1396 mb_cache_shrink(sb->s_bdev);
1397 }
1398
1399 /*
1400 * ext4_xattr_cache_insert()
1401 *
1402 * Create a new entry in the extended attribute cache, and insert
1403 * it unless such an entry is already in the cache.
1404 *
1405 * Returns 0, or a negative error number on failure.
1406 */
1407 static void
1408 ext4_xattr_cache_insert(struct buffer_head *bh)
1409 {
1410 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1411 struct mb_cache_entry *ce;
1412 int error;
1413
1414 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1415 if (!ce) {
1416 ea_bdebug(bh, "out of memory");
1417 return;
1418 }
1419 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1420 if (error) {
1421 mb_cache_entry_free(ce);
1422 if (error == -EBUSY) {
1423 ea_bdebug(bh, "already in cache");
1424 error = 0;
1425 }
1426 } else {
1427 ea_bdebug(bh, "inserting [%x]", (int)hash);
1428 mb_cache_entry_release(ce);
1429 }
1430 }
1431
1432 /*
1433 * ext4_xattr_cmp()
1434 *
1435 * Compare two extended attribute blocks for equality.
1436 *
1437 * Returns 0 if the blocks are equal, 1 if they differ, and
1438 * a negative error number on errors.
1439 */
1440 static int
1441 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1442 struct ext4_xattr_header *header2)
1443 {
1444 struct ext4_xattr_entry *entry1, *entry2;
1445
1446 entry1 = ENTRY(header1+1);
1447 entry2 = ENTRY(header2+1);
1448 while (!IS_LAST_ENTRY(entry1)) {
1449 if (IS_LAST_ENTRY(entry2))
1450 return 1;
1451 if (entry1->e_hash != entry2->e_hash ||
1452 entry1->e_name_index != entry2->e_name_index ||
1453 entry1->e_name_len != entry2->e_name_len ||
1454 entry1->e_value_size != entry2->e_value_size ||
1455 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1456 return 1;
1457 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1458 return -EIO;
1459 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1460 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1461 le32_to_cpu(entry1->e_value_size)))
1462 return 1;
1463
1464 entry1 = EXT4_XATTR_NEXT(entry1);
1465 entry2 = EXT4_XATTR_NEXT(entry2);
1466 }
1467 if (!IS_LAST_ENTRY(entry2))
1468 return 1;
1469 return 0;
1470 }
1471
1472 /*
1473 * ext4_xattr_cache_find()
1474 *
1475 * Find an identical extended attribute block.
1476 *
1477 * Returns a pointer to the block found, or NULL if such a block was
1478 * not found or an error occurred.
1479 */
1480 static struct buffer_head *
1481 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1482 struct mb_cache_entry **pce)
1483 {
1484 __u32 hash = le32_to_cpu(header->h_hash);
1485 struct mb_cache_entry *ce;
1486
1487 if (!header->h_hash)
1488 return NULL; /* never share */
1489 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1490 again:
1491 ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1492 hash);
1493 while (ce) {
1494 struct buffer_head *bh;
1495
1496 if (IS_ERR(ce)) {
1497 if (PTR_ERR(ce) == -EAGAIN)
1498 goto again;
1499 break;
1500 }
1501 bh = sb_bread(inode->i_sb, ce->e_block);
1502 if (!bh) {
1503 EXT4_ERROR_INODE(inode, "block %lu read error",
1504 (unsigned long) ce->e_block);
1505 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1506 EXT4_XATTR_REFCOUNT_MAX) {
1507 ea_idebug(inode, "block %lu refcount %d>=%d",
1508 (unsigned long) ce->e_block,
1509 le32_to_cpu(BHDR(bh)->h_refcount),
1510 EXT4_XATTR_REFCOUNT_MAX);
1511 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1512 *pce = ce;
1513 return bh;
1514 }
1515 brelse(bh);
1516 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1517 }
1518 return NULL;
1519 }
1520
1521 #define NAME_HASH_SHIFT 5
1522 #define VALUE_HASH_SHIFT 16
1523
1524 /*
1525 * ext4_xattr_hash_entry()
1526 *
1527 * Compute the hash of an extended attribute.
1528 */
1529 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1530 struct ext4_xattr_entry *entry)
1531 {
1532 __u32 hash = 0;
1533 char *name = entry->e_name;
1534 int n;
1535
1536 for (n = 0; n < entry->e_name_len; n++) {
1537 hash = (hash << NAME_HASH_SHIFT) ^
1538 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1539 *name++;
1540 }
1541
1542 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1543 __le32 *value = (__le32 *)((char *)header +
1544 le16_to_cpu(entry->e_value_offs));
1545 for (n = (le32_to_cpu(entry->e_value_size) +
1546 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1547 hash = (hash << VALUE_HASH_SHIFT) ^
1548 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1549 le32_to_cpu(*value++);
1550 }
1551 }
1552 entry->e_hash = cpu_to_le32(hash);
1553 }
1554
1555 #undef NAME_HASH_SHIFT
1556 #undef VALUE_HASH_SHIFT
1557
1558 #define BLOCK_HASH_SHIFT 16
1559
1560 /*
1561 * ext4_xattr_rehash()
1562 *
1563 * Re-compute the extended attribute hash value after an entry has changed.
1564 */
1565 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1566 struct ext4_xattr_entry *entry)
1567 {
1568 struct ext4_xattr_entry *here;
1569 __u32 hash = 0;
1570
1571 ext4_xattr_hash_entry(header, entry);
1572 here = ENTRY(header+1);
1573 while (!IS_LAST_ENTRY(here)) {
1574 if (!here->e_hash) {
1575 /* Block is not shared if an entry's hash value == 0 */
1576 hash = 0;
1577 break;
1578 }
1579 hash = (hash << BLOCK_HASH_SHIFT) ^
1580 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1581 le32_to_cpu(here->e_hash);
1582 here = EXT4_XATTR_NEXT(here);
1583 }
1584 header->h_hash = cpu_to_le32(hash);
1585 }
1586
1587 #undef BLOCK_HASH_SHIFT
1588
1589 int __init
1590 ext4_init_xattr(void)
1591 {
1592 ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1593 if (!ext4_xattr_cache)
1594 return -ENOMEM;
1595 return 0;
1596 }
1597
1598 void
1599 ext4_exit_xattr(void)
1600 {
1601 if (ext4_xattr_cache)
1602 mb_cache_destroy(ext4_xattr_cache);
1603 ext4_xattr_cache = NULL;
1604 }
Linux kernel - Deliverables
This page took 0.116761 seconds and 5 git commands to generate.