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Avoid beyond bounds copy while caching ACL
[zen-stable.git] / fs / ext4 / xattr.c
blob4410ae70fce06527de2321f90f29c462d13c086c
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 int error;
162
163 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
164 BHDR(bh)->h_blocks != cpu_to_le32(1))
165 return -EIO;
166 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
167 return error;
168 }
169
170 static inline int
171 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
172 {
173 size_t value_size = le32_to_cpu(entry->e_value_size);
174
175 if (entry->e_value_block != 0 || value_size > size ||
176 le16_to_cpu(entry->e_value_offs) + value_size > size)
177 return -EIO;
178 return 0;
179 }
180
181 static int
182 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
183 const char *name, size_t size, int sorted)
184 {
185 struct ext4_xattr_entry *entry;
186 size_t name_len;
187 int cmp = 1;
188
189 if (name == NULL)
190 return -EINVAL;
191 name_len = strlen(name);
192 entry = *pentry;
193 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
194 cmp = name_index - entry->e_name_index;
195 if (!cmp)
196 cmp = name_len - entry->e_name_len;
197 if (!cmp)
198 cmp = memcmp(name, entry->e_name, name_len);
199 if (cmp <= 0 && (sorted || cmp == 0))
200 break;
201 }
202 *pentry = entry;
203 if (!cmp && ext4_xattr_check_entry(entry, size))
204 return -EIO;
205 return cmp ? -ENODATA : 0;
206 }
207
208 static int
209 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
210 void *buffer, size_t buffer_size)
211 {
212 struct buffer_head *bh = NULL;
213 struct ext4_xattr_entry *entry;
214 size_t size;
215 int error;
216
217 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
218 name_index, name, buffer, (long)buffer_size);
219
220 error = -ENODATA;
221 if (!EXT4_I(inode)->i_file_acl)
222 goto cleanup;
223 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
224 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
225 if (!bh)
226 goto cleanup;
227 ea_bdebug(bh, "b_count=%d, refcount=%d",
228 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
229 if (ext4_xattr_check_block(bh)) {
230 bad_block:
231 EXT4_ERROR_INODE(inode, "bad block %llu",
232 EXT4_I(inode)->i_file_acl);
233 error = -EIO;
234 goto cleanup;
235 }
236 ext4_xattr_cache_insert(bh);
237 entry = BFIRST(bh);
238 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
239 if (error == -EIO)
240 goto bad_block;
241 if (error)
242 goto cleanup;
243 size = le32_to_cpu(entry->e_value_size);
244 if (buffer) {
245 error = -ERANGE;
246 if (size > buffer_size)
247 goto cleanup;
248 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
249 size);
250 }
251 error = size;
252
253 cleanup:
254 brelse(bh);
255 return error;
256 }
257
258 static int
259 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
260 void *buffer, size_t buffer_size)
261 {
262 struct ext4_xattr_ibody_header *header;
263 struct ext4_xattr_entry *entry;
264 struct ext4_inode *raw_inode;
265 struct ext4_iloc iloc;
266 size_t size;
267 void *end;
268 int error;
269
270 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
271 return -ENODATA;
272 error = ext4_get_inode_loc(inode, &iloc);
273 if (error)
274 return error;
275 raw_inode = ext4_raw_inode(&iloc);
276 header = IHDR(inode, raw_inode);
277 entry = IFIRST(header);
278 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
279 error = ext4_xattr_check_names(entry, end);
280 if (error)
281 goto cleanup;
282 error = ext4_xattr_find_entry(&entry, name_index, name,
283 end - (void *)entry, 0);
284 if (error)
285 goto cleanup;
286 size = le32_to_cpu(entry->e_value_size);
287 if (buffer) {
288 error = -ERANGE;
289 if (size > buffer_size)
290 goto cleanup;
291 memcpy(buffer, (void *)IFIRST(header) +
292 le16_to_cpu(entry->e_value_offs), size);
293 }
294 error = size;
295
296 cleanup:
297 brelse(iloc.bh);
298 return error;
299 }
300
301 /*
302 * ext4_xattr_get()
303 *
304 * Copy an extended attribute into the buffer
305 * provided, or compute the buffer size required.
306 * Buffer is NULL to compute the size of the buffer required.
307 *
308 * Returns a negative error number on failure, or the number of bytes
309 * used / required on success.
310 */
311 int
312 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
313 void *buffer, size_t buffer_size)
314 {
315 int error;
316
317 down_read(&EXT4_I(inode)->xattr_sem);
318 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
319 buffer_size);
320 if (error == -ENODATA)
321 error = ext4_xattr_block_get(inode, name_index, name, buffer,
322 buffer_size);
323 up_read(&EXT4_I(inode)->xattr_sem);
324 return error;
325 }
326
327 static int
328 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
329 char *buffer, size_t buffer_size)
330 {
331 size_t rest = buffer_size;
332
333 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
334 const struct xattr_handler *handler =
335 ext4_xattr_handler(entry->e_name_index);
336
337 if (handler) {
338 size_t size = handler->list(dentry, buffer, rest,
339 entry->e_name,
340 entry->e_name_len,
341 handler->flags);
342 if (buffer) {
343 if (size > rest)
344 return -ERANGE;
345 buffer += size;
346 }
347 rest -= size;
348 }
349 }
350 return buffer_size - rest;
351 }
352
353 static int
354 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
355 {
356 struct inode *inode = dentry->d_inode;
357 struct buffer_head *bh = NULL;
358 int error;
359
360 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
361 buffer, (long)buffer_size);
362
363 error = 0;
364 if (!EXT4_I(inode)->i_file_acl)
365 goto cleanup;
366 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
367 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
368 error = -EIO;
369 if (!bh)
370 goto cleanup;
371 ea_bdebug(bh, "b_count=%d, refcount=%d",
372 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
373 if (ext4_xattr_check_block(bh)) {
374 EXT4_ERROR_INODE(inode, "bad block %llu",
375 EXT4_I(inode)->i_file_acl);
376 error = -EIO;
377 goto cleanup;
378 }
379 ext4_xattr_cache_insert(bh);
380 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
381
382 cleanup:
383 brelse(bh);
384
385 return error;
386 }
387
388 static int
389 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
390 {
391 struct inode *inode = dentry->d_inode;
392 struct ext4_xattr_ibody_header *header;
393 struct ext4_inode *raw_inode;
394 struct ext4_iloc iloc;
395 void *end;
396 int error;
397
398 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
399 return 0;
400 error = ext4_get_inode_loc(inode, &iloc);
401 if (error)
402 return error;
403 raw_inode = ext4_raw_inode(&iloc);
404 header = IHDR(inode, raw_inode);
405 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
406 error = ext4_xattr_check_names(IFIRST(header), end);
407 if (error)
408 goto cleanup;
409 error = ext4_xattr_list_entries(dentry, IFIRST(header),
410 buffer, buffer_size);
411
412 cleanup:
413 brelse(iloc.bh);
414 return error;
415 }
416
417 /*
418 * ext4_xattr_list()
419 *
420 * Copy a list of attribute names into the buffer
421 * provided, or compute the buffer size required.
422 * Buffer is NULL to compute the size of the buffer required.
423 *
424 * Returns a negative error number on failure, or the number of bytes
425 * used / required on success.
426 */
427 static int
428 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
429 {
430 int ret, ret2;
431
432 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
433 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
434 if (ret < 0)
435 goto errout;
436 if (buffer) {
437 buffer += ret;
438 buffer_size -= ret;
439 }
440 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
441 if (ret < 0)
442 goto errout;
443 ret += ret2;
444 errout:
445 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
446 return ret;
447 }
448
449 /*
450 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
451 * not set, set it.
452 */
453 static void ext4_xattr_update_super_block(handle_t *handle,
454 struct super_block *sb)
455 {
456 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
457 return;
458
459 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
460 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
461 ext4_handle_dirty_super(handle, sb);
462 }
463 }
464
465 /*
466 * Release the xattr block BH: If the reference count is > 1, decrement
467 * it; otherwise free the block.
468 */
469 static void
470 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
471 struct buffer_head *bh)
472 {
473 struct mb_cache_entry *ce = NULL;
474 int error = 0;
475
476 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
477 error = ext4_journal_get_write_access(handle, bh);
478 if (error)
479 goto out;
480
481 lock_buffer(bh);
482 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
483 ea_bdebug(bh, "refcount now=0; freeing");
484 if (ce)
485 mb_cache_entry_free(ce);
486 get_bh(bh);
487 ext4_free_blocks(handle, inode, bh, 0, 1,
488 EXT4_FREE_BLOCKS_METADATA |
489 EXT4_FREE_BLOCKS_FORGET);
490 unlock_buffer(bh);
491 } else {
492 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
493 if (ce)
494 mb_cache_entry_release(ce);
495 unlock_buffer(bh);
496 error = ext4_handle_dirty_metadata(handle, inode, bh);
497 if (IS_SYNC(inode))
498 ext4_handle_sync(handle);
499 dquot_free_block(inode, 1);
500 ea_bdebug(bh, "refcount now=%d; releasing",
501 le32_to_cpu(BHDR(bh)->h_refcount));
502 }
503 out:
504 ext4_std_error(inode->i_sb, error);
505 return;
506 }
507
508 /*
509 * Find the available free space for EAs. This also returns the total number of
510 * bytes used by EA entries.
511 */
512 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
513 size_t *min_offs, void *base, int *total)
514 {
515 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
516 *total += EXT4_XATTR_LEN(last->e_name_len);
517 if (!last->e_value_block && last->e_value_size) {
518 size_t offs = le16_to_cpu(last->e_value_offs);
519 if (offs < *min_offs)
520 *min_offs = offs;
521 }
522 }
523 return (*min_offs - ((void *)last - base) - sizeof(__u32));
524 }
525
526 struct ext4_xattr_info {
527 int name_index;
528 const char *name;
529 const void *value;
530 size_t value_len;
531 };
532
533 struct ext4_xattr_search {
534 struct ext4_xattr_entry *first;
535 void *base;
536 void *end;
537 struct ext4_xattr_entry *here;
538 int not_found;
539 };
540
541 static int
542 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
543 {
544 struct ext4_xattr_entry *last;
545 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
546
547 /* Compute min_offs and last. */
548 last = s->first;
549 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
550 if (!last->e_value_block && last->e_value_size) {
551 size_t offs = le16_to_cpu(last->e_value_offs);
552 if (offs < min_offs)
553 min_offs = offs;
554 }
555 }
556 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
557 if (!s->not_found) {
558 if (!s->here->e_value_block && s->here->e_value_size) {
559 size_t size = le32_to_cpu(s->here->e_value_size);
560 free += EXT4_XATTR_SIZE(size);
561 }
562 free += EXT4_XATTR_LEN(name_len);
563 }
564 if (i->value) {
565 if (free < EXT4_XATTR_SIZE(i->value_len) ||
566 free < EXT4_XATTR_LEN(name_len) +
567 EXT4_XATTR_SIZE(i->value_len))
568 return -ENOSPC;
569 }
570
571 if (i->value && s->not_found) {
572 /* Insert the new name. */
573 size_t size = EXT4_XATTR_LEN(name_len);
574 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
575 memmove((void *)s->here + size, s->here, rest);
576 memset(s->here, 0, size);
577 s->here->e_name_index = i->name_index;
578 s->here->e_name_len = name_len;
579 memcpy(s->here->e_name, i->name, name_len);
580 } else {
581 if (!s->here->e_value_block && s->here->e_value_size) {
582 void *first_val = s->base + min_offs;
583 size_t offs = le16_to_cpu(s->here->e_value_offs);
584 void *val = s->base + offs;
585 size_t size = EXT4_XATTR_SIZE(
586 le32_to_cpu(s->here->e_value_size));
587
588 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
589 /* The old and the new value have the same
590 size. Just replace. */
591 s->here->e_value_size =
592 cpu_to_le32(i->value_len);
593 memset(val + size - EXT4_XATTR_PAD, 0,
594 EXT4_XATTR_PAD); /* Clear pad bytes. */
595 memcpy(val, i->value, i->value_len);
596 return 0;
597 }
598
599 /* Remove the old value. */
600 memmove(first_val + size, first_val, val - first_val);
601 memset(first_val, 0, size);
602 s->here->e_value_size = 0;
603 s->here->e_value_offs = 0;
604 min_offs += size;
605
606 /* Adjust all value offsets. */
607 last = s->first;
608 while (!IS_LAST_ENTRY(last)) {
609 size_t o = le16_to_cpu(last->e_value_offs);
610 if (!last->e_value_block &&
611 last->e_value_size && o < offs)
612 last->e_value_offs =
613 cpu_to_le16(o + size);
614 last = EXT4_XATTR_NEXT(last);
615 }
616 }
617 if (!i->value) {
618 /* Remove the old name. */
619 size_t size = EXT4_XATTR_LEN(name_len);
620 last = ENTRY((void *)last - size);
621 memmove(s->here, (void *)s->here + size,
622 (void *)last - (void *)s->here + sizeof(__u32));
623 memset(last, 0, size);
624 }
625 }
626
627 if (i->value) {
628 /* Insert the new value. */
629 s->here->e_value_size = cpu_to_le32(i->value_len);
630 if (i->value_len) {
631 size_t size = EXT4_XATTR_SIZE(i->value_len);
632 void *val = s->base + min_offs - size;
633 s->here->e_value_offs = cpu_to_le16(min_offs - size);
634 memset(val + size - EXT4_XATTR_PAD, 0,
635 EXT4_XATTR_PAD); /* Clear the pad bytes. */
636 memcpy(val, i->value, i->value_len);
637 }
638 }
639 return 0;
640 }
641
642 struct ext4_xattr_block_find {
643 struct ext4_xattr_search s;
644 struct buffer_head *bh;
645 };
646
647 static int
648 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
649 struct ext4_xattr_block_find *bs)
650 {
651 struct super_block *sb = inode->i_sb;
652 int error;
653
654 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
655 i->name_index, i->name, i->value, (long)i->value_len);
656
657 if (EXT4_I(inode)->i_file_acl) {
658 /* The inode already has an extended attribute block. */
659 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
660 error = -EIO;
661 if (!bs->bh)
662 goto cleanup;
663 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
664 atomic_read(&(bs->bh->b_count)),
665 le32_to_cpu(BHDR(bs->bh)->h_refcount));
666 if (ext4_xattr_check_block(bs->bh)) {
667 EXT4_ERROR_INODE(inode, "bad block %llu",
668 EXT4_I(inode)->i_file_acl);
669 error = -EIO;
670 goto cleanup;
671 }
672 /* Find the named attribute. */
673 bs->s.base = BHDR(bs->bh);
674 bs->s.first = BFIRST(bs->bh);
675 bs->s.end = bs->bh->b_data + bs->bh->b_size;
676 bs->s.here = bs->s.first;
677 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
678 i->name, bs->bh->b_size, 1);
679 if (error && error != -ENODATA)
680 goto cleanup;
681 bs->s.not_found = error;
682 }
683 error = 0;
684
685 cleanup:
686 return error;
687 }
688
689 static int
690 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
691 struct ext4_xattr_info *i,
692 struct ext4_xattr_block_find *bs)
693 {
694 struct super_block *sb = inode->i_sb;
695 struct buffer_head *new_bh = NULL;
696 struct ext4_xattr_search *s = &bs->s;
697 struct mb_cache_entry *ce = NULL;
698 int error = 0;
699
700 #define header(x) ((struct ext4_xattr_header *)(x))
701
702 if (i->value && i->value_len > sb->s_blocksize)
703 return -ENOSPC;
704 if (s->base) {
705 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
706 bs->bh->b_blocknr);
707 error = ext4_journal_get_write_access(handle, bs->bh);
708 if (error)
709 goto cleanup;
710 lock_buffer(bs->bh);
711
712 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
713 if (ce) {
714 mb_cache_entry_free(ce);
715 ce = NULL;
716 }
717 ea_bdebug(bs->bh, "modifying in-place");
718 error = ext4_xattr_set_entry(i, s);
719 if (!error) {
720 if (!IS_LAST_ENTRY(s->first))
721 ext4_xattr_rehash(header(s->base),
722 s->here);
723 ext4_xattr_cache_insert(bs->bh);
724 }
725 unlock_buffer(bs->bh);
726 if (error == -EIO)
727 goto bad_block;
728 if (!error)
729 error = ext4_handle_dirty_metadata(handle,
730 inode,
731 bs->bh);
732 if (error)
733 goto cleanup;
734 goto inserted;
735 } else {
736 int offset = (char *)s->here - bs->bh->b_data;
737
738 unlock_buffer(bs->bh);
739 ext4_handle_release_buffer(handle, bs->bh);
740 if (ce) {
741 mb_cache_entry_release(ce);
742 ce = NULL;
743 }
744 ea_bdebug(bs->bh, "cloning");
745 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
746 error = -ENOMEM;
747 if (s->base == NULL)
748 goto cleanup;
749 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
750 s->first = ENTRY(header(s->base)+1);
751 header(s->base)->h_refcount = cpu_to_le32(1);
752 s->here = ENTRY(s->base + offset);
753 s->end = s->base + bs->bh->b_size;
754 }
755 } else {
756 /* Allocate a buffer where we construct the new block. */
757 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
758 /* assert(header == s->base) */
759 error = -ENOMEM;
760 if (s->base == NULL)
761 goto cleanup;
762 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
763 header(s->base)->h_blocks = cpu_to_le32(1);
764 header(s->base)->h_refcount = cpu_to_le32(1);
765 s->first = ENTRY(header(s->base)+1);
766 s->here = ENTRY(header(s->base)+1);
767 s->end = s->base + sb->s_blocksize;
768 }
769
770 error = ext4_xattr_set_entry(i, s);
771 if (error == -EIO)
772 goto bad_block;
773 if (error)
774 goto cleanup;
775 if (!IS_LAST_ENTRY(s->first))
776 ext4_xattr_rehash(header(s->base), s->here);
777
778 inserted:
779 if (!IS_LAST_ENTRY(s->first)) {
780 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
781 if (new_bh) {
782 /* We found an identical block in the cache. */
783 if (new_bh == bs->bh)
784 ea_bdebug(new_bh, "keeping");
785 else {
786 /* The old block is released after updating
787 the inode. */
788 error = dquot_alloc_block(inode, 1);
789 if (error)
790 goto cleanup;
791 error = ext4_journal_get_write_access(handle,
792 new_bh);
793 if (error)
794 goto cleanup_dquot;
795 lock_buffer(new_bh);
796 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
797 ea_bdebug(new_bh, "reusing; refcount now=%d",
798 le32_to_cpu(BHDR(new_bh)->h_refcount));
799 unlock_buffer(new_bh);
800 error = ext4_handle_dirty_metadata(handle,
801 inode,
802 new_bh);
803 if (error)
804 goto cleanup_dquot;
805 }
806 mb_cache_entry_release(ce);
807 ce = NULL;
808 } else if (bs->bh && s->base == bs->bh->b_data) {
809 /* We were modifying this block in-place. */
810 ea_bdebug(bs->bh, "keeping this block");
811 new_bh = bs->bh;
812 get_bh(new_bh);
813 } else {
814 /* We need to allocate a new block */
815 ext4_fsblk_t goal, block;
816
817 goal = ext4_group_first_block_no(sb,
818 EXT4_I(inode)->i_block_group);
819
820 /* non-extent files can't have physical blocks past 2^32 */
821 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
822 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
823
824 /*
825 * take i_data_sem because we will test
826 * i_delalloc_reserved_flag in ext4_mb_new_blocks
827 */
828 down_read((&EXT4_I(inode)->i_data_sem));
829 block = ext4_new_meta_blocks(handle, inode, goal, 0,
830 NULL, &error);
831 up_read((&EXT4_I(inode)->i_data_sem));
832 if (error)
833 goto cleanup;
834
835 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
836 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
837
838 ea_idebug(inode, "creating block %d", block);
839
840 new_bh = sb_getblk(sb, block);
841 if (!new_bh) {
842 getblk_failed:
843 ext4_free_blocks(handle, inode, NULL, block, 1,
844 EXT4_FREE_BLOCKS_METADATA);
845 error = -EIO;
846 goto cleanup;
847 }
848 lock_buffer(new_bh);
849 error = ext4_journal_get_create_access(handle, new_bh);
850 if (error) {
851 unlock_buffer(new_bh);
852 goto getblk_failed;
853 }
854 memcpy(new_bh->b_data, s->base, new_bh->b_size);
855 set_buffer_uptodate(new_bh);
856 unlock_buffer(new_bh);
857 ext4_xattr_cache_insert(new_bh);
858 error = ext4_handle_dirty_metadata(handle,
859 inode, new_bh);
860 if (error)
861 goto cleanup;
862 }
863 }
864
865 /* Update the inode. */
866 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
867
868 /* Drop the previous xattr block. */
869 if (bs->bh && bs->bh != new_bh)
870 ext4_xattr_release_block(handle, inode, bs->bh);
871 error = 0;
872
873 cleanup:
874 if (ce)
875 mb_cache_entry_release(ce);
876 brelse(new_bh);
877 if (!(bs->bh && s->base == bs->bh->b_data))
878 kfree(s->base);
879
880 return error;
881
882 cleanup_dquot:
883 dquot_free_block(inode, 1);
884 goto cleanup;
885
886 bad_block:
887 EXT4_ERROR_INODE(inode, "bad block %llu",
888 EXT4_I(inode)->i_file_acl);
889 goto cleanup;
890
891 #undef header
892 }
893
894 struct ext4_xattr_ibody_find {
895 struct ext4_xattr_search s;
896 struct ext4_iloc iloc;
897 };
898
899 static int
900 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
901 struct ext4_xattr_ibody_find *is)
902 {
903 struct ext4_xattr_ibody_header *header;
904 struct ext4_inode *raw_inode;
905 int error;
906
907 if (EXT4_I(inode)->i_extra_isize == 0)
908 return 0;
909 raw_inode = ext4_raw_inode(&is->iloc);
910 header = IHDR(inode, raw_inode);
911 is->s.base = is->s.first = IFIRST(header);
912 is->s.here = is->s.first;
913 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
914 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
915 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
916 if (error)
917 return error;
918 /* Find the named attribute. */
919 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
920 i->name, is->s.end -
921 (void *)is->s.base, 0);
922 if (error && error != -ENODATA)
923 return error;
924 is->s.not_found = error;
925 }
926 return 0;
927 }
928
929 static int
930 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
931 struct ext4_xattr_info *i,
932 struct ext4_xattr_ibody_find *is)
933 {
934 struct ext4_xattr_ibody_header *header;
935 struct ext4_xattr_search *s = &is->s;
936 int error;
937
938 if (EXT4_I(inode)->i_extra_isize == 0)
939 return -ENOSPC;
940 error = ext4_xattr_set_entry(i, s);
941 if (error)
942 return error;
943 header = IHDR(inode, ext4_raw_inode(&is->iloc));
944 if (!IS_LAST_ENTRY(s->first)) {
945 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
946 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
947 } else {
948 header->h_magic = cpu_to_le32(0);
949 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
950 }
951 return 0;
952 }
953
954 /*
955 * ext4_xattr_set_handle()
956 *
957 * Create, replace or remove an extended attribute for this inode. Value
958 * is NULL to remove an existing extended attribute, and non-NULL to
959 * either replace an existing extended attribute, or create a new extended
960 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
961 * specify that an extended attribute must exist and must not exist
962 * previous to the call, respectively.
963 *
964 * Returns 0, or a negative error number on failure.
965 */
966 int
967 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
968 const char *name, const void *value, size_t value_len,
969 int flags)
970 {
971 struct ext4_xattr_info i = {
972 .name_index = name_index,
973 .name = name,
974 .value = value,
975 .value_len = value_len,
976
977 };
978 struct ext4_xattr_ibody_find is = {
979 .s = { .not_found = -ENODATA, },
980 };
981 struct ext4_xattr_block_find bs = {
982 .s = { .not_found = -ENODATA, },
983 };
984 unsigned long no_expand;
985 int error;
986
987 if (!name)
988 return -EINVAL;
989 if (strlen(name) > 255)
990 return -ERANGE;
991 down_write(&EXT4_I(inode)->xattr_sem);
992 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
993 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
994
995 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
996 if (error)
997 goto cleanup;
998
999 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1000 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1001 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1002 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1003 }
1004
1005 error = ext4_xattr_ibody_find(inode, &i, &is);
1006 if (error)
1007 goto cleanup;
1008 if (is.s.not_found)
1009 error = ext4_xattr_block_find(inode, &i, &bs);
1010 if (error)
1011 goto cleanup;
1012 if (is.s.not_found && bs.s.not_found) {
1013 error = -ENODATA;
1014 if (flags & XATTR_REPLACE)
1015 goto cleanup;
1016 error = 0;
1017 if (!value)
1018 goto cleanup;
1019 } else {
1020 error = -EEXIST;
1021 if (flags & XATTR_CREATE)
1022 goto cleanup;
1023 }
1024 if (!value) {
1025 if (!is.s.not_found)
1026 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1027 else if (!bs.s.not_found)
1028 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1029 } else {
1030 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1031 if (!error && !bs.s.not_found) {
1032 i.value = NULL;
1033 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1034 } else if (error == -ENOSPC) {
1035 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1036 error = ext4_xattr_block_find(inode, &i, &bs);
1037 if (error)
1038 goto cleanup;
1039 }
1040 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1041 if (error)
1042 goto cleanup;
1043 if (!is.s.not_found) {
1044 i.value = NULL;
1045 error = ext4_xattr_ibody_set(handle, inode, &i,
1046 &is);
1047 }
1048 }
1049 }
1050 if (!error) {
1051 ext4_xattr_update_super_block(handle, inode->i_sb);
1052 inode->i_ctime = ext4_current_time(inode);
1053 if (!value)
1054 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1055 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1056 /*
1057 * The bh is consumed by ext4_mark_iloc_dirty, even with
1058 * error != 0.
1059 */
1060 is.iloc.bh = NULL;
1061 if (IS_SYNC(inode))
1062 ext4_handle_sync(handle);
1063 }
1064
1065 cleanup:
1066 brelse(is.iloc.bh);
1067 brelse(bs.bh);
1068 if (no_expand == 0)
1069 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1070 up_write(&EXT4_I(inode)->xattr_sem);
1071 return error;
1072 }
1073
1074 /*
1075 * ext4_xattr_set()
1076 *
1077 * Like ext4_xattr_set_handle, but start from an inode. This extended
1078 * attribute modification is a filesystem transaction by itself.
1079 *
1080 * Returns 0, or a negative error number on failure.
1081 */
1082 int
1083 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1084 const void *value, size_t value_len, int flags)
1085 {
1086 handle_t *handle;
1087 int error, retries = 0;
1088
1089 retry:
1090 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1091 if (IS_ERR(handle)) {
1092 error = PTR_ERR(handle);
1093 } else {
1094 int error2;
1095
1096 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1097 value, value_len, flags);
1098 error2 = ext4_journal_stop(handle);
1099 if (error == -ENOSPC &&
1100 ext4_should_retry_alloc(inode->i_sb, &retries))
1101 goto retry;
1102 if (error == 0)
1103 error = error2;
1104 }
1105
1106 return error;
1107 }
1108
1109 /*
1110 * Shift the EA entries in the inode to create space for the increased
1111 * i_extra_isize.
1112 */
1113 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1114 int value_offs_shift, void *to,
1115 void *from, size_t n, int blocksize)
1116 {
1117 struct ext4_xattr_entry *last = entry;
1118 int new_offs;
1119
1120 /* Adjust the value offsets of the entries */
1121 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1122 if (!last->e_value_block && last->e_value_size) {
1123 new_offs = le16_to_cpu(last->e_value_offs) +
1124 value_offs_shift;
1125 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1126 > blocksize);
1127 last->e_value_offs = cpu_to_le16(new_offs);
1128 }
1129 }
1130 /* Shift the entries by n bytes */
1131 memmove(to, from, n);
1132 }
1133
1134 /*
1135 * Expand an inode by new_extra_isize bytes when EAs are present.
1136 * Returns 0 on success or negative error number on failure.
1137 */
1138 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1139 struct ext4_inode *raw_inode, handle_t *handle)
1140 {
1141 struct ext4_xattr_ibody_header *header;
1142 struct ext4_xattr_entry *entry, *last, *first;
1143 struct buffer_head *bh = NULL;
1144 struct ext4_xattr_ibody_find *is = NULL;
1145 struct ext4_xattr_block_find *bs = NULL;
1146 char *buffer = NULL, *b_entry_name = NULL;
1147 size_t min_offs, free;
1148 int total_ino, total_blk;
1149 void *base, *start, *end;
1150 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1151 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1152
1153 down_write(&EXT4_I(inode)->xattr_sem);
1154 retry:
1155 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1156 up_write(&EXT4_I(inode)->xattr_sem);
1157 return 0;
1158 }
1159
1160 header = IHDR(inode, raw_inode);
1161 entry = IFIRST(header);
1162
1163 /*
1164 * Check if enough free space is available in the inode to shift the
1165 * entries ahead by new_extra_isize.
1166 */
1167
1168 base = start = entry;
1169 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1170 min_offs = end - base;
1171 last = entry;
1172 total_ino = sizeof(struct ext4_xattr_ibody_header);
1173
1174 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1175 if (free >= new_extra_isize) {
1176 entry = IFIRST(header);
1177 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1178 - new_extra_isize, (void *)raw_inode +
1179 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1180 (void *)header, total_ino,
1181 inode->i_sb->s_blocksize);
1182 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1183 error = 0;
1184 goto cleanup;
1185 }
1186
1187 /*
1188 * Enough free space isn't available in the inode, check if
1189 * EA block can hold new_extra_isize bytes.
1190 */
1191 if (EXT4_I(inode)->i_file_acl) {
1192 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1193 error = -EIO;
1194 if (!bh)
1195 goto cleanup;
1196 if (ext4_xattr_check_block(bh)) {
1197 EXT4_ERROR_INODE(inode, "bad block %llu",
1198 EXT4_I(inode)->i_file_acl);
1199 error = -EIO;
1200 goto cleanup;
1201 }
1202 base = BHDR(bh);
1203 first = BFIRST(bh);
1204 end = bh->b_data + bh->b_size;
1205 min_offs = end - base;
1206 free = ext4_xattr_free_space(first, &min_offs, base,
1207 &total_blk);
1208 if (free < new_extra_isize) {
1209 if (!tried_min_extra_isize && s_min_extra_isize) {
1210 tried_min_extra_isize++;
1211 new_extra_isize = s_min_extra_isize;
1212 brelse(bh);
1213 goto retry;
1214 }
1215 error = -1;
1216 goto cleanup;
1217 }
1218 } else {
1219 free = inode->i_sb->s_blocksize;
1220 }
1221
1222 while (new_extra_isize > 0) {
1223 size_t offs, size, entry_size;
1224 struct ext4_xattr_entry *small_entry = NULL;
1225 struct ext4_xattr_info i = {
1226 .value = NULL,
1227 .value_len = 0,
1228 };
1229 unsigned int total_size; /* EA entry size + value size */
1230 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1231 unsigned int min_total_size = ~0U;
1232
1233 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1234 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1235 if (!is || !bs) {
1236 error = -ENOMEM;
1237 goto cleanup;
1238 }
1239
1240 is->s.not_found = -ENODATA;
1241 bs->s.not_found = -ENODATA;
1242 is->iloc.bh = NULL;
1243 bs->bh = NULL;
1244
1245 last = IFIRST(header);
1246 /* Find the entry best suited to be pushed into EA block */
1247 entry = NULL;
1248 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1249 total_size =
1250 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1251 EXT4_XATTR_LEN(last->e_name_len);
1252 if (total_size <= free && total_size < min_total_size) {
1253 if (total_size < new_extra_isize) {
1254 small_entry = last;
1255 } else {
1256 entry = last;
1257 min_total_size = total_size;
1258 }
1259 }
1260 }
1261
1262 if (entry == NULL) {
1263 if (small_entry) {
1264 entry = small_entry;
1265 } else {
1266 if (!tried_min_extra_isize &&
1267 s_min_extra_isize) {
1268 tried_min_extra_isize++;
1269 new_extra_isize = s_min_extra_isize;
1270 goto retry;
1271 }
1272 error = -1;
1273 goto cleanup;
1274 }
1275 }
1276 offs = le16_to_cpu(entry->e_value_offs);
1277 size = le32_to_cpu(entry->e_value_size);
1278 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1279 i.name_index = entry->e_name_index,
1280 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1281 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1282 if (!buffer || !b_entry_name) {
1283 error = -ENOMEM;
1284 goto cleanup;
1285 }
1286 /* Save the entry name and the entry value */
1287 memcpy(buffer, (void *)IFIRST(header) + offs,
1288 EXT4_XATTR_SIZE(size));
1289 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1290 b_entry_name[entry->e_name_len] = '\0';
1291 i.name = b_entry_name;
1292
1293 error = ext4_get_inode_loc(inode, &is->iloc);
1294 if (error)
1295 goto cleanup;
1296
1297 error = ext4_xattr_ibody_find(inode, &i, is);
1298 if (error)
1299 goto cleanup;
1300
1301 /* Remove the chosen entry from the inode */
1302 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1303 if (error)
1304 goto cleanup;
1305
1306 entry = IFIRST(header);
1307 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1308 shift_bytes = new_extra_isize;
1309 else
1310 shift_bytes = entry_size + size;
1311 /* Adjust the offsets and shift the remaining entries ahead */
1312 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1313 shift_bytes, (void *)raw_inode +
1314 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1315 (void *)header, total_ino - entry_size,
1316 inode->i_sb->s_blocksize);
1317
1318 extra_isize += shift_bytes;
1319 new_extra_isize -= shift_bytes;
1320 EXT4_I(inode)->i_extra_isize = extra_isize;
1321
1322 i.name = b_entry_name;
1323 i.value = buffer;
1324 i.value_len = size;
1325 error = ext4_xattr_block_find(inode, &i, bs);
1326 if (error)
1327 goto cleanup;
1328
1329 /* Add entry which was removed from the inode into the block */
1330 error = ext4_xattr_block_set(handle, inode, &i, bs);
1331 if (error)
1332 goto cleanup;
1333 kfree(b_entry_name);
1334 kfree(buffer);
1335 b_entry_name = NULL;
1336 buffer = NULL;
1337 brelse(is->iloc.bh);
1338 kfree(is);
1339 kfree(bs);
1340 }
1341 brelse(bh);
1342 up_write(&EXT4_I(inode)->xattr_sem);
1343 return 0;
1344
1345 cleanup:
1346 kfree(b_entry_name);
1347 kfree(buffer);
1348 if (is)
1349 brelse(is->iloc.bh);
1350 kfree(is);
1351 kfree(bs);
1352 brelse(bh);
1353 up_write(&EXT4_I(inode)->xattr_sem);
1354 return error;
1355 }
1356
1357
1358
1359 /*
1360 * ext4_xattr_delete_inode()
1361 *
1362 * Free extended attribute resources associated with this inode. This
1363 * is called immediately before an inode is freed. We have exclusive
1364 * access to the inode.
1365 */
1366 void
1367 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1368 {
1369 struct buffer_head *bh = NULL;
1370
1371 if (!EXT4_I(inode)->i_file_acl)
1372 goto cleanup;
1373 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1374 if (!bh) {
1375 EXT4_ERROR_INODE(inode, "block %llu read error",
1376 EXT4_I(inode)->i_file_acl);
1377 goto cleanup;
1378 }
1379 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1380 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1381 EXT4_ERROR_INODE(inode, "bad block %llu",
1382 EXT4_I(inode)->i_file_acl);
1383 goto cleanup;
1384 }
1385 ext4_xattr_release_block(handle, inode, bh);
1386 EXT4_I(inode)->i_file_acl = 0;
1387
1388 cleanup:
1389 brelse(bh);
1390 }
1391
1392 /*
1393 * ext4_xattr_put_super()
1394 *
1395 * This is called when a file system is unmounted.
1396 */
1397 void
1398 ext4_xattr_put_super(struct super_block *sb)
1399 {
1400 mb_cache_shrink(sb->s_bdev);
1401 }
1402
1403 /*
1404 * ext4_xattr_cache_insert()
1405 *
1406 * Create a new entry in the extended attribute cache, and insert
1407 * it unless such an entry is already in the cache.
1408 *
1409 * Returns 0, or a negative error number on failure.
1410 */
1411 static void
1412 ext4_xattr_cache_insert(struct buffer_head *bh)
1413 {
1414 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1415 struct mb_cache_entry *ce;
1416 int error;
1417
1418 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1419 if (!ce) {
1420 ea_bdebug(bh, "out of memory");
1421 return;
1422 }
1423 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1424 if (error) {
1425 mb_cache_entry_free(ce);
1426 if (error == -EBUSY) {
1427 ea_bdebug(bh, "already in cache");
1428 error = 0;
1429 }
1430 } else {
1431 ea_bdebug(bh, "inserting [%x]", (int)hash);
1432 mb_cache_entry_release(ce);
1433 }
1434 }
1435
1436 /*
1437 * ext4_xattr_cmp()
1438 *
1439 * Compare two extended attribute blocks for equality.
1440 *
1441 * Returns 0 if the blocks are equal, 1 if they differ, and
1442 * a negative error number on errors.
1443 */
1444 static int
1445 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1446 struct ext4_xattr_header *header2)
1447 {
1448 struct ext4_xattr_entry *entry1, *entry2;
1449
1450 entry1 = ENTRY(header1+1);
1451 entry2 = ENTRY(header2+1);
1452 while (!IS_LAST_ENTRY(entry1)) {
1453 if (IS_LAST_ENTRY(entry2))
1454 return 1;
1455 if (entry1->e_hash != entry2->e_hash ||
1456 entry1->e_name_index != entry2->e_name_index ||
1457 entry1->e_name_len != entry2->e_name_len ||
1458 entry1->e_value_size != entry2->e_value_size ||
1459 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1460 return 1;
1461 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1462 return -EIO;
1463 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1464 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1465 le32_to_cpu(entry1->e_value_size)))
1466 return 1;
1467
1468 entry1 = EXT4_XATTR_NEXT(entry1);
1469 entry2 = EXT4_XATTR_NEXT(entry2);
1470 }
1471 if (!IS_LAST_ENTRY(entry2))
1472 return 1;
1473 return 0;
1474 }
1475
1476 /*
1477 * ext4_xattr_cache_find()
1478 *
1479 * Find an identical extended attribute block.
1480 *
1481 * Returns a pointer to the block found, or NULL if such a block was
1482 * not found or an error occurred.
1483 */
1484 static struct buffer_head *
1485 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1486 struct mb_cache_entry **pce)
1487 {
1488 __u32 hash = le32_to_cpu(header->h_hash);
1489 struct mb_cache_entry *ce;
1490
1491 if (!header->h_hash)
1492 return NULL; /* never share */
1493 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1494 again:
1495 ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1496 hash);
1497 while (ce) {
1498 struct buffer_head *bh;
1499
1500 if (IS_ERR(ce)) {
1501 if (PTR_ERR(ce) == -EAGAIN)
1502 goto again;
1503 break;
1504 }
1505 bh = sb_bread(inode->i_sb, ce->e_block);
1506 if (!bh) {
1507 EXT4_ERROR_INODE(inode, "block %lu read error",
1508 (unsigned long) ce->e_block);
1509 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1510 EXT4_XATTR_REFCOUNT_MAX) {
1511 ea_idebug(inode, "block %lu refcount %d>=%d",
1512 (unsigned long) ce->e_block,
1513 le32_to_cpu(BHDR(bh)->h_refcount),
1514 EXT4_XATTR_REFCOUNT_MAX);
1515 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1516 *pce = ce;
1517 return bh;
1518 }
1519 brelse(bh);
1520 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1521 }
1522 return NULL;
1523 }
1524
1525 #define NAME_HASH_SHIFT 5
1526 #define VALUE_HASH_SHIFT 16
1527
1528 /*
1529 * ext4_xattr_hash_entry()
1530 *
1531 * Compute the hash of an extended attribute.
1532 */
1533 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1534 struct ext4_xattr_entry *entry)
1535 {
1536 __u32 hash = 0;
1537 char *name = entry->e_name;
1538 int n;
1539
1540 for (n = 0; n < entry->e_name_len; n++) {
1541 hash = (hash << NAME_HASH_SHIFT) ^
1542 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1543 *name++;
1544 }
1545
1546 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1547 __le32 *value = (__le32 *)((char *)header +
1548 le16_to_cpu(entry->e_value_offs));
1549 for (n = (le32_to_cpu(entry->e_value_size) +
1550 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1551 hash = (hash << VALUE_HASH_SHIFT) ^
1552 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1553 le32_to_cpu(*value++);
1554 }
1555 }
1556 entry->e_hash = cpu_to_le32(hash);
1557 }
1558
1559 #undef NAME_HASH_SHIFT
1560 #undef VALUE_HASH_SHIFT
1561
1562 #define BLOCK_HASH_SHIFT 16
1563
1564 /*
1565 * ext4_xattr_rehash()
1566 *
1567 * Re-compute the extended attribute hash value after an entry has changed.
1568 */
1569 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1570 struct ext4_xattr_entry *entry)
1571 {
1572 struct ext4_xattr_entry *here;
1573 __u32 hash = 0;
1574
1575 ext4_xattr_hash_entry(header, entry);
1576 here = ENTRY(header+1);
1577 while (!IS_LAST_ENTRY(here)) {
1578 if (!here->e_hash) {
1579 /* Block is not shared if an entry's hash value == 0 */
1580 hash = 0;
1581 break;
1582 }
1583 hash = (hash << BLOCK_HASH_SHIFT) ^
1584 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1585 le32_to_cpu(here->e_hash);
1586 here = EXT4_XATTR_NEXT(here);
1587 }
1588 header->h_hash = cpu_to_le32(hash);
1589 }
1590
1591 #undef BLOCK_HASH_SHIFT
1592
1593 int __init
1594 ext4_init_xattr(void)
1595 {
1596 ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1597 if (!ext4_xattr_cache)
1598 return -ENOMEM;
1599 return 0;
1600 }
1601
1602 void
1603 ext4_exit_xattr(void)
1604 {
1605 if (ext4_xattr_cache)
1606 mb_cache_destroy(ext4_xattr_cache);
1607 ext4_xattr_cache = NULL;
1608 }