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1 /*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16 /*
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53 #include <linux/init.h>
54 #include <linux/fs.h>
55 #include <linux/slab.h>
56 #include <linux/ext4_jbd2.h>
57 #include <linux/ext4_fs.h>
58 #include <linux/mbcache.h>
59 #include <linux/quotaops.h>
60 #include <linux/rwsem.h>
61 #include "xattr.h"
62 #include "acl.h"
63
64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
68
69 #ifdef EXT4_XATTR_DEBUG
70 # define ea_idebug(inode, f...) do { \
71 printk(KERN_DEBUG "inode %s:%lu: ", \
72 inode->i_sb->s_id, inode->i_ino); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76 # define ea_bdebug(bh, f...) do { \
77 char b[BDEVNAME_SIZE]; \
78 printk(KERN_DEBUG "block %s:%lu: ", \
79 bdevname(bh->b_bdev, b), \
80 (unsigned long) bh->b_blocknr); \
81 printk(f); \
82 printk("\n"); \
83 } while (0)
84 #else
85 # define ea_idebug(f...)
86 # define ea_bdebug(f...)
87 #endif
88
89 static void ext4_xattr_cache_insert(struct buffer_head *);
90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
91 struct ext4_xattr_header *,
92 struct mb_cache_entry **);
93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
94 struct ext4_xattr_entry *);
95
96 static struct mb_cache *ext4_xattr_cache;
97
98 static struct xattr_handler *ext4_xattr_handler_map[] = {
99 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
100 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
101 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
102 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
103 #endif
104 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
105 #ifdef CONFIG_EXT4DEV_FS_SECURITY
106 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
107 #endif
108 };
109
110 struct xattr_handler *ext4_xattr_handlers[] = {
111 &ext4_xattr_user_handler,
112 &ext4_xattr_trusted_handler,
113 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
114 &ext4_xattr_acl_access_handler,
115 &ext4_xattr_acl_default_handler,
116 #endif
117 #ifdef CONFIG_EXT4DEV_FS_SECURITY
118 &ext4_xattr_security_handler,
119 #endif
120 NULL
121 };
122
123 static inline struct xattr_handler *
124 ext4_xattr_handler(int name_index)
125 {
126 struct xattr_handler *handler = NULL;
127
128 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
129 handler = ext4_xattr_handler_map[name_index];
130 return handler;
131 }
132
133 /*
134 * Inode operation listxattr()
135 *
136 * dentry->d_inode->i_mutex: don't care
137 */
138 ssize_t
139 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
140 {
141 return ext4_xattr_list(dentry->d_inode, buffer, size);
142 }
143
144 static int
145 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
146 {
147 while (!IS_LAST_ENTRY(entry)) {
148 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
149 if ((void *)next >= end)
150 return -EIO;
151 entry = next;
152 }
153 return 0;
154 }
155
156 static inline int
157 ext4_xattr_check_block(struct buffer_head *bh)
158 {
159 int error;
160
161 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
162 BHDR(bh)->h_blocks != cpu_to_le32(1))
163 return -EIO;
164 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
165 return error;
166 }
167
168 static inline int
169 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
170 {
171 size_t value_size = le32_to_cpu(entry->e_value_size);
172
173 if (entry->e_value_block != 0 || value_size > size ||
174 le16_to_cpu(entry->e_value_offs) + value_size > size)
175 return -EIO;
176 return 0;
177 }
178
179 static int
180 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
181 const char *name, size_t size, int sorted)
182 {
183 struct ext4_xattr_entry *entry;
184 size_t name_len;
185 int cmp = 1;
186
187 if (name == NULL)
188 return -EINVAL;
189 name_len = strlen(name);
190 entry = *pentry;
191 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
192 cmp = name_index - entry->e_name_index;
193 if (!cmp)
194 cmp = name_len - entry->e_name_len;
195 if (!cmp)
196 cmp = memcmp(name, entry->e_name, name_len);
197 if (cmp <= 0 && (sorted || cmp == 0))
198 break;
199 }
200 *pentry = entry;
201 if (!cmp && ext4_xattr_check_entry(entry, size))
202 return -EIO;
203 return cmp ? -ENODATA : 0;
204 }
205
206 static int
207 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
208 void *buffer, size_t buffer_size)
209 {
210 struct buffer_head *bh = NULL;
211 struct ext4_xattr_entry *entry;
212 size_t size;
213 int error;
214
215 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
216 name_index, name, buffer, (long)buffer_size);
217
218 error = -ENODATA;
219 if (!EXT4_I(inode)->i_file_acl)
220 goto cleanup;
221 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
222 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
223 if (!bh)
224 goto cleanup;
225 ea_bdebug(bh, "b_count=%d, refcount=%d",
226 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
227 if (ext4_xattr_check_block(bh)) {
228 bad_block: ext4_error(inode->i_sb, __FUNCTION__,
229 "inode %lu: bad block %llu", inode->i_ino,
230 EXT4_I(inode)->i_file_acl);
231 error = -EIO;
232 goto cleanup;
233 }
234 ext4_xattr_cache_insert(bh);
235 entry = BFIRST(bh);
236 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
237 if (error == -EIO)
238 goto bad_block;
239 if (error)
240 goto cleanup;
241 size = le32_to_cpu(entry->e_value_size);
242 if (buffer) {
243 error = -ERANGE;
244 if (size > buffer_size)
245 goto cleanup;
246 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
247 size);
248 }
249 error = size;
250
251 cleanup:
252 brelse(bh);
253 return error;
254 }
255
256 static int
257 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
258 void *buffer, size_t buffer_size)
259 {
260 struct ext4_xattr_ibody_header *header;
261 struct ext4_xattr_entry *entry;
262 struct ext4_inode *raw_inode;
263 struct ext4_iloc iloc;
264 size_t size;
265 void *end;
266 int error;
267
268 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
269 return -ENODATA;
270 error = ext4_get_inode_loc(inode, &iloc);
271 if (error)
272 return error;
273 raw_inode = ext4_raw_inode(&iloc);
274 header = IHDR(inode, raw_inode);
275 entry = IFIRST(header);
276 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
277 error = ext4_xattr_check_names(entry, end);
278 if (error)
279 goto cleanup;
280 error = ext4_xattr_find_entry(&entry, name_index, name,
281 end - (void *)entry, 0);
282 if (error)
283 goto cleanup;
284 size = le32_to_cpu(entry->e_value_size);
285 if (buffer) {
286 error = -ERANGE;
287 if (size > buffer_size)
288 goto cleanup;
289 memcpy(buffer, (void *)IFIRST(header) +
290 le16_to_cpu(entry->e_value_offs), size);
291 }
292 error = size;
293
294 cleanup:
295 brelse(iloc.bh);
296 return error;
297 }
298
299 /*
300 * ext4_xattr_get()
301 *
302 * Copy an extended attribute into the buffer
303 * provided, or compute the buffer size required.
304 * Buffer is NULL to compute the size of the buffer required.
305 *
306 * Returns a negative error number on failure, or the number of bytes
307 * used / required on success.
308 */
309 int
310 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
311 void *buffer, size_t buffer_size)
312 {
313 int error;
314
315 down_read(&EXT4_I(inode)->xattr_sem);
316 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
317 buffer_size);
318 if (error == -ENODATA)
319 error = ext4_xattr_block_get(inode, name_index, name, buffer,
320 buffer_size);
321 up_read(&EXT4_I(inode)->xattr_sem);
322 return error;
323 }
324
325 static int
326 ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry,
327 char *buffer, size_t buffer_size)
328 {
329 size_t rest = buffer_size;
330
331 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
332 struct xattr_handler *handler =
333 ext4_xattr_handler(entry->e_name_index);
334
335 if (handler) {
336 size_t size = handler->list(inode, buffer, rest,
337 entry->e_name,
338 entry->e_name_len);
339 if (buffer) {
340 if (size > rest)
341 return -ERANGE;
342 buffer += size;
343 }
344 rest -= size;
345 }
346 }
347 return buffer_size - rest;
348 }
349
350 static int
351 ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
352 {
353 struct buffer_head *bh = NULL;
354 int error;
355
356 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
357 buffer, (long)buffer_size);
358
359 error = 0;
360 if (!EXT4_I(inode)->i_file_acl)
361 goto cleanup;
362 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
363 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
364 error = -EIO;
365 if (!bh)
366 goto cleanup;
367 ea_bdebug(bh, "b_count=%d, refcount=%d",
368 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
369 if (ext4_xattr_check_block(bh)) {
370 ext4_error(inode->i_sb, __FUNCTION__,
371 "inode %lu: bad block %llu", inode->i_ino,
372 EXT4_I(inode)->i_file_acl);
373 error = -EIO;
374 goto cleanup;
375 }
376 ext4_xattr_cache_insert(bh);
377 error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
378
379 cleanup:
380 brelse(bh);
381
382 return error;
383 }
384
385 static int
386 ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
387 {
388 struct ext4_xattr_ibody_header *header;
389 struct ext4_inode *raw_inode;
390 struct ext4_iloc iloc;
391 void *end;
392 int error;
393
394 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
395 return 0;
396 error = ext4_get_inode_loc(inode, &iloc);
397 if (error)
398 return error;
399 raw_inode = ext4_raw_inode(&iloc);
400 header = IHDR(inode, raw_inode);
401 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
402 error = ext4_xattr_check_names(IFIRST(header), end);
403 if (error)
404 goto cleanup;
405 error = ext4_xattr_list_entries(inode, IFIRST(header),
406 buffer, buffer_size);
407
408 cleanup:
409 brelse(iloc.bh);
410 return error;
411 }
412
413 /*
414 * ext4_xattr_list()
415 *
416 * Copy a list of attribute names into the buffer
417 * provided, or compute the buffer size required.
418 * Buffer is NULL to compute the size of the buffer required.
419 *
420 * Returns a negative error number on failure, or the number of bytes
421 * used / required on success.
422 */
423 int
424 ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
425 {
426 int i_error, b_error;
427
428 down_read(&EXT4_I(inode)->xattr_sem);
429 i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size);
430 if (i_error < 0) {
431 b_error = 0;
432 } else {
433 if (buffer) {
434 buffer += i_error;
435 buffer_size -= i_error;
436 }
437 b_error = ext4_xattr_block_list(inode, buffer, buffer_size);
438 if (b_error < 0)
439 i_error = 0;
440 }
441 up_read(&EXT4_I(inode)->xattr_sem);
442 return i_error + b_error;
443 }
444
445 /*
446 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
447 * not set, set it.
448 */
449 static void ext4_xattr_update_super_block(handle_t *handle,
450 struct super_block *sb)
451 {
452 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
453 return;
454
455 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
456 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
457 sb->s_dirt = 1;
458 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
459 }
460 }
461
462 /*
463 * Release the xattr block BH: If the reference count is > 1, decrement
464 * it; otherwise free the block.
465 */
466 static void
467 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
468 struct buffer_head *bh)
469 {
470 struct mb_cache_entry *ce = NULL;
471 int error = 0;
472
473 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
474 error = ext4_journal_get_write_access(handle, bh);
475 if (error)
476 goto out;
477
478 lock_buffer(bh);
479 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
480 ea_bdebug(bh, "refcount now=0; freeing");
481 if (ce)
482 mb_cache_entry_free(ce);
483 ext4_free_blocks(handle, inode, bh->b_blocknr, 1, 1);
484 get_bh(bh);
485 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
486 } else {
487 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
488 error = ext4_journal_dirty_metadata(handle, bh);
489 if (IS_SYNC(inode))
490 handle->h_sync = 1;
491 DQUOT_FREE_BLOCK(inode, 1);
492 ea_bdebug(bh, "refcount now=%d; releasing",
493 le32_to_cpu(BHDR(bh)->h_refcount));
494 if (ce)
495 mb_cache_entry_release(ce);
496 }
497 unlock_buffer(bh);
498 out:
499 ext4_std_error(inode->i_sb, error);
500 return;
501 }
502
503 /*
504 * Find the available free space for EAs. This also returns the total number of
505 * bytes used by EA entries.
506 */
507 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
508 size_t *min_offs, void *base, int *total)
509 {
510 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
511 *total += EXT4_XATTR_LEN(last->e_name_len);
512 if (!last->e_value_block && last->e_value_size) {
513 size_t offs = le16_to_cpu(last->e_value_offs);
514 if (offs < *min_offs)
515 *min_offs = offs;
516 }
517 }
518 return (*min_offs - ((void *)last - base) - sizeof(__u32));
519 }
520
521 struct ext4_xattr_info {
522 int name_index;
523 const char *name;
524 const void *value;
525 size_t value_len;
526 };
527
528 struct ext4_xattr_search {
529 struct ext4_xattr_entry *first;
530 void *base;
531 void *end;
532 struct ext4_xattr_entry *here;
533 int not_found;
534 };
535
536 static int
537 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
538 {
539 struct ext4_xattr_entry *last;
540 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
541
542 /* Compute min_offs and last. */
543 last = s->first;
544 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
545 if (!last->e_value_block && last->e_value_size) {
546 size_t offs = le16_to_cpu(last->e_value_offs);
547 if (offs < min_offs)
548 min_offs = offs;
549 }
550 }
551 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
552 if (!s->not_found) {
553 if (!s->here->e_value_block && s->here->e_value_size) {
554 size_t size = le32_to_cpu(s->here->e_value_size);
555 free += EXT4_XATTR_SIZE(size);
556 }
557 free += EXT4_XATTR_LEN(name_len);
558 }
559 if (i->value) {
560 if (free < EXT4_XATTR_SIZE(i->value_len) ||
561 free < EXT4_XATTR_LEN(name_len) +
562 EXT4_XATTR_SIZE(i->value_len))
563 return -ENOSPC;
564 }
565
566 if (i->value && s->not_found) {
567 /* Insert the new name. */
568 size_t size = EXT4_XATTR_LEN(name_len);
569 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
570 memmove((void *)s->here + size, s->here, rest);
571 memset(s->here, 0, size);
572 s->here->e_name_index = i->name_index;
573 s->here->e_name_len = name_len;
574 memcpy(s->here->e_name, i->name, name_len);
575 } else {
576 if (!s->here->e_value_block && s->here->e_value_size) {
577 void *first_val = s->base + min_offs;
578 size_t offs = le16_to_cpu(s->here->e_value_offs);
579 void *val = s->base + offs;
580 size_t size = EXT4_XATTR_SIZE(
581 le32_to_cpu(s->here->e_value_size));
582
583 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
584 /* The old and the new value have the same
585 size. Just replace. */
586 s->here->e_value_size =
587 cpu_to_le32(i->value_len);
588 memset(val + size - EXT4_XATTR_PAD, 0,
589 EXT4_XATTR_PAD); /* Clear pad bytes. */
590 memcpy(val, i->value, i->value_len);
591 return 0;
592 }
593
594 /* Remove the old value. */
595 memmove(first_val + size, first_val, val - first_val);
596 memset(first_val, 0, size);
597 s->here->e_value_size = 0;
598 s->here->e_value_offs = 0;
599 min_offs += size;
600
601 /* Adjust all value offsets. */
602 last = s->first;
603 while (!IS_LAST_ENTRY(last)) {
604 size_t o = le16_to_cpu(last->e_value_offs);
605 if (!last->e_value_block &&
606 last->e_value_size && o < offs)
607 last->e_value_offs =
608 cpu_to_le16(o + size);
609 last = EXT4_XATTR_NEXT(last);
610 }
611 }
612 if (!i->value) {
613 /* Remove the old name. */
614 size_t size = EXT4_XATTR_LEN(name_len);
615 last = ENTRY((void *)last - size);
616 memmove(s->here, (void *)s->here + size,
617 (void *)last - (void *)s->here + sizeof(__u32));
618 memset(last, 0, size);
619 }
620 }
621
622 if (i->value) {
623 /* Insert the new value. */
624 s->here->e_value_size = cpu_to_le32(i->value_len);
625 if (i->value_len) {
626 size_t size = EXT4_XATTR_SIZE(i->value_len);
627 void *val = s->base + min_offs - size;
628 s->here->e_value_offs = cpu_to_le16(min_offs - size);
629 memset(val + size - EXT4_XATTR_PAD, 0,
630 EXT4_XATTR_PAD); /* Clear the pad bytes. */
631 memcpy(val, i->value, i->value_len);
632 }
633 }
634 return 0;
635 }
636
637 struct ext4_xattr_block_find {
638 struct ext4_xattr_search s;
639 struct buffer_head *bh;
640 };
641
642 static int
643 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
644 struct ext4_xattr_block_find *bs)
645 {
646 struct super_block *sb = inode->i_sb;
647 int error;
648
649 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
650 i->name_index, i->name, i->value, (long)i->value_len);
651
652 if (EXT4_I(inode)->i_file_acl) {
653 /* The inode already has an extended attribute block. */
654 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
655 error = -EIO;
656 if (!bs->bh)
657 goto cleanup;
658 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
659 atomic_read(&(bs->bh->b_count)),
660 le32_to_cpu(BHDR(bs->bh)->h_refcount));
661 if (ext4_xattr_check_block(bs->bh)) {
662 ext4_error(sb, __FUNCTION__,
663 "inode %lu: bad block %llu", inode->i_ino,
664 EXT4_I(inode)->i_file_acl);
665 error = -EIO;
666 goto cleanup;
667 }
668 /* Find the named attribute. */
669 bs->s.base = BHDR(bs->bh);
670 bs->s.first = BFIRST(bs->bh);
671 bs->s.end = bs->bh->b_data + bs->bh->b_size;
672 bs->s.here = bs->s.first;
673 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
674 i->name, bs->bh->b_size, 1);
675 if (error && error != -ENODATA)
676 goto cleanup;
677 bs->s.not_found = error;
678 }
679 error = 0;
680
681 cleanup:
682 return error;
683 }
684
685 static int
686 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
687 struct ext4_xattr_info *i,
688 struct ext4_xattr_block_find *bs)
689 {
690 struct super_block *sb = inode->i_sb;
691 struct buffer_head *new_bh = NULL;
692 struct ext4_xattr_search *s = &bs->s;
693 struct mb_cache_entry *ce = NULL;
694 int error = 0;
695
696 #define header(x) ((struct ext4_xattr_header *)(x))
697
698 if (i->value && i->value_len > sb->s_blocksize)
699 return -ENOSPC;
700 if (s->base) {
701 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
702 bs->bh->b_blocknr);
703 error = ext4_journal_get_write_access(handle, bs->bh);
704 if (error)
705 goto cleanup;
706 lock_buffer(bs->bh);
707
708 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
709 if (ce) {
710 mb_cache_entry_free(ce);
711 ce = NULL;
712 }
713 ea_bdebug(bs->bh, "modifying in-place");
714 error = ext4_xattr_set_entry(i, s);
715 if (!error) {
716 if (!IS_LAST_ENTRY(s->first))
717 ext4_xattr_rehash(header(s->base),
718 s->here);
719 ext4_xattr_cache_insert(bs->bh);
720 }
721 unlock_buffer(bs->bh);
722 if (error == -EIO)
723 goto bad_block;
724 if (!error)
725 error = ext4_journal_dirty_metadata(handle,
726 bs->bh);
727 if (error)
728 goto cleanup;
729 goto inserted;
730 } else {
731 int offset = (char *)s->here - bs->bh->b_data;
732
733 unlock_buffer(bs->bh);
734 jbd2_journal_release_buffer(handle, bs->bh);
735 if (ce) {
736 mb_cache_entry_release(ce);
737 ce = NULL;
738 }
739 ea_bdebug(bs->bh, "cloning");
740 s->base = kmalloc(bs->bh->b_size, GFP_KERNEL);
741 error = -ENOMEM;
742 if (s->base == NULL)
743 goto cleanup;
744 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
745 s->first = ENTRY(header(s->base)+1);
746 header(s->base)->h_refcount = cpu_to_le32(1);
747 s->here = ENTRY(s->base + offset);
748 s->end = s->base + bs->bh->b_size;
749 }
750 } else {
751 /* Allocate a buffer where we construct the new block. */
752 s->base = kzalloc(sb->s_blocksize, GFP_KERNEL);
753 /* assert(header == s->base) */
754 error = -ENOMEM;
755 if (s->base == NULL)
756 goto cleanup;
757 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
758 header(s->base)->h_blocks = cpu_to_le32(1);
759 header(s->base)->h_refcount = cpu_to_le32(1);
760 s->first = ENTRY(header(s->base)+1);
761 s->here = ENTRY(header(s->base)+1);
762 s->end = s->base + sb->s_blocksize;
763 }
764
765 error = ext4_xattr_set_entry(i, s);
766 if (error == -EIO)
767 goto bad_block;
768 if (error)
769 goto cleanup;
770 if (!IS_LAST_ENTRY(s->first))
771 ext4_xattr_rehash(header(s->base), s->here);
772
773 inserted:
774 if (!IS_LAST_ENTRY(s->first)) {
775 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
776 if (new_bh) {
777 /* We found an identical block in the cache. */
778 if (new_bh == bs->bh)
779 ea_bdebug(new_bh, "keeping");
780 else {
781 /* The old block is released after updating
782 the inode. */
783 error = -EDQUOT;
784 if (DQUOT_ALLOC_BLOCK(inode, 1))
785 goto cleanup;
786 error = ext4_journal_get_write_access(handle,
787 new_bh);
788 if (error)
789 goto cleanup_dquot;
790 lock_buffer(new_bh);
791 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
792 ea_bdebug(new_bh, "reusing; refcount now=%d",
793 le32_to_cpu(BHDR(new_bh)->h_refcount));
794 unlock_buffer(new_bh);
795 error = ext4_journal_dirty_metadata(handle,
796 new_bh);
797 if (error)
798 goto cleanup_dquot;
799 }
800 mb_cache_entry_release(ce);
801 ce = NULL;
802 } else if (bs->bh && s->base == bs->bh->b_data) {
803 /* We were modifying this block in-place. */
804 ea_bdebug(bs->bh, "keeping this block");
805 new_bh = bs->bh;
806 get_bh(new_bh);
807 } else {
808 /* We need to allocate a new block */
809 ext4_fsblk_t goal = le32_to_cpu(
810 EXT4_SB(sb)->s_es->s_first_data_block) +
811 (ext4_fsblk_t)EXT4_I(inode)->i_block_group *
812 EXT4_BLOCKS_PER_GROUP(sb);
813 ext4_fsblk_t block = ext4_new_block(handle, inode,
814 goal, &error);
815 if (error)
816 goto cleanup;
817 ea_idebug(inode, "creating block %d", block);
818
819 new_bh = sb_getblk(sb, block);
820 if (!new_bh) {
821 getblk_failed:
822 ext4_free_blocks(handle, inode, block, 1, 1);
823 error = -EIO;
824 goto cleanup;
825 }
826 lock_buffer(new_bh);
827 error = ext4_journal_get_create_access(handle, new_bh);
828 if (error) {
829 unlock_buffer(new_bh);
830 goto getblk_failed;
831 }
832 memcpy(new_bh->b_data, s->base, new_bh->b_size);
833 set_buffer_uptodate(new_bh);
834 unlock_buffer(new_bh);
835 ext4_xattr_cache_insert(new_bh);
836 error = ext4_journal_dirty_metadata(handle, new_bh);
837 if (error)
838 goto cleanup;
839 }
840 }
841
842 /* Update the inode. */
843 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
844
845 /* Drop the previous xattr block. */
846 if (bs->bh && bs->bh != new_bh)
847 ext4_xattr_release_block(handle, inode, bs->bh);
848 error = 0;
849
850 cleanup:
851 if (ce)
852 mb_cache_entry_release(ce);
853 brelse(new_bh);
854 if (!(bs->bh && s->base == bs->bh->b_data))
855 kfree(s->base);
856
857 return error;
858
859 cleanup_dquot:
860 DQUOT_FREE_BLOCK(inode, 1);
861 goto cleanup;
862
863 bad_block:
864 ext4_error(inode->i_sb, __FUNCTION__,
865 "inode %lu: bad block %llu", inode->i_ino,
866 EXT4_I(inode)->i_file_acl);
867 goto cleanup;
868
869 #undef header
870 }
871
872 struct ext4_xattr_ibody_find {
873 struct ext4_xattr_search s;
874 struct ext4_iloc iloc;
875 };
876
877 static int
878 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
879 struct ext4_xattr_ibody_find *is)
880 {
881 struct ext4_xattr_ibody_header *header;
882 struct ext4_inode *raw_inode;
883 int error;
884
885 if (EXT4_I(inode)->i_extra_isize == 0)
886 return 0;
887 raw_inode = ext4_raw_inode(&is->iloc);
888 header = IHDR(inode, raw_inode);
889 is->s.base = is->s.first = IFIRST(header);
890 is->s.here = is->s.first;
891 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
892 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
893 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
894 if (error)
895 return error;
896 /* Find the named attribute. */
897 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
898 i->name, is->s.end -
899 (void *)is->s.base, 0);
900 if (error && error != -ENODATA)
901 return error;
902 is->s.not_found = error;
903 }
904 return 0;
905 }
906
907 static int
908 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
909 struct ext4_xattr_info *i,
910 struct ext4_xattr_ibody_find *is)
911 {
912 struct ext4_xattr_ibody_header *header;
913 struct ext4_xattr_search *s = &is->s;
914 int error;
915
916 if (EXT4_I(inode)->i_extra_isize == 0)
917 return -ENOSPC;
918 error = ext4_xattr_set_entry(i, s);
919 if (error)
920 return error;
921 header = IHDR(inode, ext4_raw_inode(&is->iloc));
922 if (!IS_LAST_ENTRY(s->first)) {
923 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
924 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
925 } else {
926 header->h_magic = cpu_to_le32(0);
927 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
928 }
929 return 0;
930 }
931
932 /*
933 * ext4_xattr_set_handle()
934 *
935 * Create, replace or remove an extended attribute for this inode. Buffer
936 * is NULL to remove an existing extended attribute, and non-NULL to
937 * either replace an existing extended attribute, or create a new extended
938 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
939 * specify that an extended attribute must exist and must not exist
940 * previous to the call, respectively.
941 *
942 * Returns 0, or a negative error number on failure.
943 */
944 int
945 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
946 const char *name, const void *value, size_t value_len,
947 int flags)
948 {
949 struct ext4_xattr_info i = {
950 .name_index = name_index,
951 .name = name,
952 .value = value,
953 .value_len = value_len,
954
955 };
956 struct ext4_xattr_ibody_find is = {
957 .s = { .not_found = -ENODATA, },
958 };
959 struct ext4_xattr_block_find bs = {
960 .s = { .not_found = -ENODATA, },
961 };
962 int error;
963
964 if (!name)
965 return -EINVAL;
966 if (strlen(name) > 255)
967 return -ERANGE;
968 down_write(&EXT4_I(inode)->xattr_sem);
969 error = ext4_get_inode_loc(inode, &is.iloc);
970 if (error)
971 goto cleanup;
972
973 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
974 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
975 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
976 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
977 }
978
979 error = ext4_xattr_ibody_find(inode, &i, &is);
980 if (error)
981 goto cleanup;
982 if (is.s.not_found)
983 error = ext4_xattr_block_find(inode, &i, &bs);
984 if (error)
985 goto cleanup;
986 if (is.s.not_found && bs.s.not_found) {
987 error = -ENODATA;
988 if (flags & XATTR_REPLACE)
989 goto cleanup;
990 error = 0;
991 if (!value)
992 goto cleanup;
993 } else {
994 error = -EEXIST;
995 if (flags & XATTR_CREATE)
996 goto cleanup;
997 }
998 error = ext4_journal_get_write_access(handle, is.iloc.bh);
999 if (error)
1000 goto cleanup;
1001 if (!value) {
1002 if (!is.s.not_found)
1003 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1004 else if (!bs.s.not_found)
1005 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1006 } else {
1007 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1008 if (!error && !bs.s.not_found) {
1009 i.value = NULL;
1010 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1011 } else if (error == -ENOSPC) {
1012 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1013 if (error)
1014 goto cleanup;
1015 if (!is.s.not_found) {
1016 i.value = NULL;
1017 error = ext4_xattr_ibody_set(handle, inode, &i,
1018 &is);
1019 }
1020 }
1021 }
1022 if (!error) {
1023 ext4_xattr_update_super_block(handle, inode->i_sb);
1024 inode->i_ctime = ext4_current_time(inode);
1025 if (!value)
1026 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1027 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1028 /*
1029 * The bh is consumed by ext4_mark_iloc_dirty, even with
1030 * error != 0.
1031 */
1032 is.iloc.bh = NULL;
1033 if (IS_SYNC(inode))
1034 handle->h_sync = 1;
1035 }
1036
1037 cleanup:
1038 brelse(is.iloc.bh);
1039 brelse(bs.bh);
1040 up_write(&EXT4_I(inode)->xattr_sem);
1041 return error;
1042 }
1043
1044 /*
1045 * ext4_xattr_set()
1046 *
1047 * Like ext4_xattr_set_handle, but start from an inode. This extended
1048 * attribute modification is a filesystem transaction by itself.
1049 *
1050 * Returns 0, or a negative error number on failure.
1051 */
1052 int
1053 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1054 const void *value, size_t value_len, int flags)
1055 {
1056 handle_t *handle;
1057 int error, retries = 0;
1058
1059 retry:
1060 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1061 if (IS_ERR(handle)) {
1062 error = PTR_ERR(handle);
1063 } else {
1064 int error2;
1065
1066 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1067 value, value_len, flags);
1068 error2 = ext4_journal_stop(handle);
1069 if (error == -ENOSPC &&
1070 ext4_should_retry_alloc(inode->i_sb, &retries))
1071 goto retry;
1072 if (error == 0)
1073 error = error2;
1074 }
1075
1076 return error;
1077 }
1078
1079 /*
1080 * Shift the EA entries in the inode to create space for the increased
1081 * i_extra_isize.
1082 */
1083 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1084 int value_offs_shift, void *to,
1085 void *from, size_t n, int blocksize)
1086 {
1087 struct ext4_xattr_entry *last = entry;
1088 int new_offs;
1089
1090 /* Adjust the value offsets of the entries */
1091 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1092 if (!last->e_value_block && last->e_value_size) {
1093 new_offs = le16_to_cpu(last->e_value_offs) +
1094 value_offs_shift;
1095 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1096 > blocksize);
1097 last->e_value_offs = cpu_to_le16(new_offs);
1098 }
1099 }
1100 /* Shift the entries by n bytes */
1101 memmove(to, from, n);
1102 }
1103
1104 /*
1105 * Expand an inode by new_extra_isize bytes when EAs are present.
1106 * Returns 0 on success or negative error number on failure.
1107 */
1108 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1109 struct ext4_inode *raw_inode, handle_t *handle)
1110 {
1111 struct ext4_xattr_ibody_header *header;
1112 struct ext4_xattr_entry *entry, *last, *first;
1113 struct buffer_head *bh = NULL;
1114 struct ext4_xattr_ibody_find *is = NULL;
1115 struct ext4_xattr_block_find *bs = NULL;
1116 char *buffer = NULL, *b_entry_name = NULL;
1117 size_t min_offs, free;
1118 int total_ino, total_blk;
1119 void *base, *start, *end;
1120 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1121 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1122
1123 down_write(&EXT4_I(inode)->xattr_sem);
1124 retry:
1125 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1126 up_write(&EXT4_I(inode)->xattr_sem);
1127 return 0;
1128 }
1129
1130 header = IHDR(inode, raw_inode);
1131 entry = IFIRST(header);
1132
1133 /*
1134 * Check if enough free space is available in the inode to shift the
1135 * entries ahead by new_extra_isize.
1136 */
1137
1138 base = start = entry;
1139 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1140 min_offs = end - base;
1141 last = entry;
1142 total_ino = sizeof(struct ext4_xattr_ibody_header);
1143
1144 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1145 if (free >= new_extra_isize) {
1146 entry = IFIRST(header);
1147 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1148 - new_extra_isize, (void *)raw_inode +
1149 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1150 (void *)header, total_ino,
1151 inode->i_sb->s_blocksize);
1152 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1153 error = 0;
1154 goto cleanup;
1155 }
1156
1157 /*
1158 * Enough free space isn't available in the inode, check if
1159 * EA block can hold new_extra_isize bytes.
1160 */
1161 if (EXT4_I(inode)->i_file_acl) {
1162 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1163 error = -EIO;
1164 if (!bh)
1165 goto cleanup;
1166 if (ext4_xattr_check_block(bh)) {
1167 ext4_error(inode->i_sb, __FUNCTION__,
1168 "inode %lu: bad block %llu", inode->i_ino,
1169 EXT4_I(inode)->i_file_acl);
1170 error = -EIO;
1171 goto cleanup;
1172 }
1173 base = BHDR(bh);
1174 first = BFIRST(bh);
1175 end = bh->b_data + bh->b_size;
1176 min_offs = end - base;
1177 free = ext4_xattr_free_space(first, &min_offs, base,
1178 &total_blk);
1179 if (free < new_extra_isize) {
1180 if (!tried_min_extra_isize && s_min_extra_isize) {
1181 tried_min_extra_isize++;
1182 new_extra_isize = s_min_extra_isize;
1183 brelse(bh);
1184 goto retry;
1185 }
1186 error = -1;
1187 goto cleanup;
1188 }
1189 } else {
1190 free = inode->i_sb->s_blocksize;
1191 }
1192
1193 while (new_extra_isize > 0) {
1194 size_t offs, size, entry_size;
1195 struct ext4_xattr_entry *small_entry = NULL;
1196 struct ext4_xattr_info i = {
1197 .value = NULL,
1198 .value_len = 0,
1199 };
1200 unsigned int total_size; /* EA entry size + value size */
1201 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1202 unsigned int min_total_size = ~0U;
1203
1204 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1205 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1206 if (!is || !bs) {
1207 error = -ENOMEM;
1208 goto cleanup;
1209 }
1210
1211 is->s.not_found = -ENODATA;
1212 bs->s.not_found = -ENODATA;
1213 is->iloc.bh = NULL;
1214 bs->bh = NULL;
1215
1216 last = IFIRST(header);
1217 /* Find the entry best suited to be pushed into EA block */
1218 entry = NULL;
1219 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1220 total_size =
1221 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1222 EXT4_XATTR_LEN(last->e_name_len);
1223 if (total_size <= free && total_size < min_total_size) {
1224 if (total_size < new_extra_isize) {
1225 small_entry = last;
1226 } else {
1227 entry = last;
1228 min_total_size = total_size;
1229 }
1230 }
1231 }
1232
1233 if (entry == NULL) {
1234 if (small_entry) {
1235 entry = small_entry;
1236 } else {
1237 if (!tried_min_extra_isize &&
1238 s_min_extra_isize) {
1239 tried_min_extra_isize++;
1240 new_extra_isize = s_min_extra_isize;
1241 goto retry;
1242 }
1243 error = -1;
1244 goto cleanup;
1245 }
1246 }
1247 offs = le16_to_cpu(entry->e_value_offs);
1248 size = le32_to_cpu(entry->e_value_size);
1249 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1250 i.name_index = entry->e_name_index,
1251 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1252 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1253 if (!buffer || !b_entry_name) {
1254 error = -ENOMEM;
1255 goto cleanup;
1256 }
1257 /* Save the entry name and the entry value */
1258 memcpy(buffer, (void *)IFIRST(header) + offs,
1259 EXT4_XATTR_SIZE(size));
1260 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1261 b_entry_name[entry->e_name_len] = '\0';
1262 i.name = b_entry_name;
1263
1264 error = ext4_get_inode_loc(inode, &is->iloc);
1265 if (error)
1266 goto cleanup;
1267
1268 error = ext4_xattr_ibody_find(inode, &i, is);
1269 if (error)
1270 goto cleanup;
1271
1272 /* Remove the chosen entry from the inode */
1273 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1274
1275 entry = IFIRST(header);
1276 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1277 shift_bytes = new_extra_isize;
1278 else
1279 shift_bytes = entry_size + size;
1280 /* Adjust the offsets and shift the remaining entries ahead */
1281 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1282 shift_bytes, (void *)raw_inode +
1283 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1284 (void *)header, total_ino - entry_size,
1285 inode->i_sb->s_blocksize);
1286
1287 extra_isize += shift_bytes;
1288 new_extra_isize -= shift_bytes;
1289 EXT4_I(inode)->i_extra_isize = extra_isize;
1290
1291 i.name = b_entry_name;
1292 i.value = buffer;
1293 i.value_len = size;
1294 error = ext4_xattr_block_find(inode, &i, bs);
1295 if (error)
1296 goto cleanup;
1297
1298 /* Add entry which was removed from the inode into the block */
1299 error = ext4_xattr_block_set(handle, inode, &i, bs);
1300 if (error)
1301 goto cleanup;
1302 kfree(b_entry_name);
1303 kfree(buffer);
1304 brelse(is->iloc.bh);
1305 kfree(is);
1306 kfree(bs);
1307 }
1308 brelse(bh);
1309 up_write(&EXT4_I(inode)->xattr_sem);
1310 return 0;
1311
1312 cleanup:
1313 kfree(b_entry_name);
1314 kfree(buffer);
1315 if (is)
1316 brelse(is->iloc.bh);
1317 kfree(is);
1318 kfree(bs);
1319 brelse(bh);
1320 up_write(&EXT4_I(inode)->xattr_sem);
1321 return error;
1322 }
1323
1324
1325
1326 /*
1327 * ext4_xattr_delete_inode()
1328 *
1329 * Free extended attribute resources associated with this inode. This
1330 * is called immediately before an inode is freed. We have exclusive
1331 * access to the inode.
1332 */
1333 void
1334 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1335 {
1336 struct buffer_head *bh = NULL;
1337
1338 if (!EXT4_I(inode)->i_file_acl)
1339 goto cleanup;
1340 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1341 if (!bh) {
1342 ext4_error(inode->i_sb, __FUNCTION__,
1343 "inode %lu: block %llu read error", inode->i_ino,
1344 EXT4_I(inode)->i_file_acl);
1345 goto cleanup;
1346 }
1347 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1348 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1349 ext4_error(inode->i_sb, __FUNCTION__,
1350 "inode %lu: bad block %llu", inode->i_ino,
1351 EXT4_I(inode)->i_file_acl);
1352 goto cleanup;
1353 }
1354 ext4_xattr_release_block(handle, inode, bh);
1355 EXT4_I(inode)->i_file_acl = 0;
1356
1357 cleanup:
1358 brelse(bh);
1359 }
1360
1361 /*
1362 * ext4_xattr_put_super()
1363 *
1364 * This is called when a file system is unmounted.
1365 */
1366 void
1367 ext4_xattr_put_super(struct super_block *sb)
1368 {
1369 mb_cache_shrink(sb->s_bdev);
1370 }
1371
1372 /*
1373 * ext4_xattr_cache_insert()
1374 *
1375 * Create a new entry in the extended attribute cache, and insert
1376 * it unless such an entry is already in the cache.
1377 *
1378 * Returns 0, or a negative error number on failure.
1379 */
1380 static void
1381 ext4_xattr_cache_insert(struct buffer_head *bh)
1382 {
1383 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1384 struct mb_cache_entry *ce;
1385 int error;
1386
1387 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1388 if (!ce) {
1389 ea_bdebug(bh, "out of memory");
1390 return;
1391 }
1392 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1393 if (error) {
1394 mb_cache_entry_free(ce);
1395 if (error == -EBUSY) {
1396 ea_bdebug(bh, "already in cache");
1397 error = 0;
1398 }
1399 } else {
1400 ea_bdebug(bh, "inserting [%x]", (int)hash);
1401 mb_cache_entry_release(ce);
1402 }
1403 }
1404
1405 /*
1406 * ext4_xattr_cmp()
1407 *
1408 * Compare two extended attribute blocks for equality.
1409 *
1410 * Returns 0 if the blocks are equal, 1 if they differ, and
1411 * a negative error number on errors.
1412 */
1413 static int
1414 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1415 struct ext4_xattr_header *header2)
1416 {
1417 struct ext4_xattr_entry *entry1, *entry2;
1418
1419 entry1 = ENTRY(header1+1);
1420 entry2 = ENTRY(header2+1);
1421 while (!IS_LAST_ENTRY(entry1)) {
1422 if (IS_LAST_ENTRY(entry2))
1423 return 1;
1424 if (entry1->e_hash != entry2->e_hash ||
1425 entry1->e_name_index != entry2->e_name_index ||
1426 entry1->e_name_len != entry2->e_name_len ||
1427 entry1->e_value_size != entry2->e_value_size ||
1428 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1429 return 1;
1430 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1431 return -EIO;
1432 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1433 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1434 le32_to_cpu(entry1->e_value_size)))
1435 return 1;
1436
1437 entry1 = EXT4_XATTR_NEXT(entry1);
1438 entry2 = EXT4_XATTR_NEXT(entry2);
1439 }
1440 if (!IS_LAST_ENTRY(entry2))
1441 return 1;
1442 return 0;
1443 }
1444
1445 /*
1446 * ext4_xattr_cache_find()
1447 *
1448 * Find an identical extended attribute block.
1449 *
1450 * Returns a pointer to the block found, or NULL if such a block was
1451 * not found or an error occurred.
1452 */
1453 static struct buffer_head *
1454 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1455 struct mb_cache_entry **pce)
1456 {
1457 __u32 hash = le32_to_cpu(header->h_hash);
1458 struct mb_cache_entry *ce;
1459
1460 if (!header->h_hash)
1461 return NULL; /* never share */
1462 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1463 again:
1464 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1465 inode->i_sb->s_bdev, hash);
1466 while (ce) {
1467 struct buffer_head *bh;
1468
1469 if (IS_ERR(ce)) {
1470 if (PTR_ERR(ce) == -EAGAIN)
1471 goto again;
1472 break;
1473 }
1474 bh = sb_bread(inode->i_sb, ce->e_block);
1475 if (!bh) {
1476 ext4_error(inode->i_sb, __FUNCTION__,
1477 "inode %lu: block %lu read error",
1478 inode->i_ino, (unsigned long) ce->e_block);
1479 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1480 EXT4_XATTR_REFCOUNT_MAX) {
1481 ea_idebug(inode, "block %lu refcount %d>=%d",
1482 (unsigned long) ce->e_block,
1483 le32_to_cpu(BHDR(bh)->h_refcount),
1484 EXT4_XATTR_REFCOUNT_MAX);
1485 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1486 *pce = ce;
1487 return bh;
1488 }
1489 brelse(bh);
1490 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1491 }
1492 return NULL;
1493 }
1494
1495 #define NAME_HASH_SHIFT 5
1496 #define VALUE_HASH_SHIFT 16
1497
1498 /*
1499 * ext4_xattr_hash_entry()
1500 *
1501 * Compute the hash of an extended attribute.
1502 */
1503 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1504 struct ext4_xattr_entry *entry)
1505 {
1506 __u32 hash = 0;
1507 char *name = entry->e_name;
1508 int n;
1509
1510 for (n=0; n < entry->e_name_len; n++) {
1511 hash = (hash << NAME_HASH_SHIFT) ^
1512 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1513 *name++;
1514 }
1515
1516 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1517 __le32 *value = (__le32 *)((char *)header +
1518 le16_to_cpu(entry->e_value_offs));
1519 for (n = (le32_to_cpu(entry->e_value_size) +
1520 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1521 hash = (hash << VALUE_HASH_SHIFT) ^
1522 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1523 le32_to_cpu(*value++);
1524 }
1525 }
1526 entry->e_hash = cpu_to_le32(hash);
1527 }
1528
1529 #undef NAME_HASH_SHIFT
1530 #undef VALUE_HASH_SHIFT
1531
1532 #define BLOCK_HASH_SHIFT 16
1533
1534 /*
1535 * ext4_xattr_rehash()
1536 *
1537 * Re-compute the extended attribute hash value after an entry has changed.
1538 */
1539 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1540 struct ext4_xattr_entry *entry)
1541 {
1542 struct ext4_xattr_entry *here;
1543 __u32 hash = 0;
1544
1545 ext4_xattr_hash_entry(header, entry);
1546 here = ENTRY(header+1);
1547 while (!IS_LAST_ENTRY(here)) {
1548 if (!here->e_hash) {
1549 /* Block is not shared if an entry's hash value == 0 */
1550 hash = 0;
1551 break;
1552 }
1553 hash = (hash << BLOCK_HASH_SHIFT) ^
1554 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1555 le32_to_cpu(here->e_hash);
1556 here = EXT4_XATTR_NEXT(here);
1557 }
1558 header->h_hash = cpu_to_le32(hash);
1559 }
1560
1561 #undef BLOCK_HASH_SHIFT
1562
1563 int __init
1564 init_ext4_xattr(void)
1565 {
1566 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1567 sizeof(struct mb_cache_entry) +
1568 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1569 if (!ext4_xattr_cache)
1570 return -ENOMEM;
1571 return 0;
1572 }
1573
1574 void
1575 exit_ext4_xattr(void)
1576 {
1577 if (ext4_xattr_cache)
1578 mb_cache_destroy(ext4_xattr_cache);
1579 ext4_xattr_cache = NULL;
1580 }
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