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Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6
[deliverable/linux.git] / fs / ext4 / xattr.c
1 /*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16 /*
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53 #include <linux/init.h>
54 #include <linux/fs.h>
55 #include <linux/slab.h>
56 #include <linux/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);
484 get_bh(bh);
485 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
486 } else {
487 BHDR(bh)->h_refcount = cpu_to_le32(
488 le32_to_cpu(BHDR(bh)->h_refcount) - 1);
489 error = ext4_journal_dirty_metadata(handle, bh);
490 if (IS_SYNC(inode))
491 handle->h_sync = 1;
492 DQUOT_FREE_BLOCK(inode, 1);
493 ea_bdebug(bh, "refcount now=%d; releasing",
494 le32_to_cpu(BHDR(bh)->h_refcount));
495 if (ce)
496 mb_cache_entry_release(ce);
497 }
498 unlock_buffer(bh);
499 out:
500 ext4_std_error(inode->i_sb, error);
501 return;
502 }
503
504 /*
505 * Find the available free space for EAs. This also returns the total number of
506 * bytes used by EA entries.
507 */
508 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
509 size_t *min_offs, void *base, int *total)
510 {
511 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
512 *total += EXT4_XATTR_LEN(last->e_name_len);
513 if (!last->e_value_block && last->e_value_size) {
514 size_t offs = le16_to_cpu(last->e_value_offs);
515 if (offs < *min_offs)
516 *min_offs = offs;
517 }
518 }
519 return (*min_offs - ((void *)last - base) - sizeof(__u32));
520 }
521
522 struct ext4_xattr_info {
523 int name_index;
524 const char *name;
525 const void *value;
526 size_t value_len;
527 };
528
529 struct ext4_xattr_search {
530 struct ext4_xattr_entry *first;
531 void *base;
532 void *end;
533 struct ext4_xattr_entry *here;
534 int not_found;
535 };
536
537 static int
538 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
539 {
540 struct ext4_xattr_entry *last;
541 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
542
543 /* Compute min_offs and last. */
544 last = s->first;
545 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
546 if (!last->e_value_block && last->e_value_size) {
547 size_t offs = le16_to_cpu(last->e_value_offs);
548 if (offs < min_offs)
549 min_offs = offs;
550 }
551 }
552 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
553 if (!s->not_found) {
554 if (!s->here->e_value_block && s->here->e_value_size) {
555 size_t size = le32_to_cpu(s->here->e_value_size);
556 free += EXT4_XATTR_SIZE(size);
557 }
558 free += EXT4_XATTR_LEN(name_len);
559 }
560 if (i->value) {
561 if (free < EXT4_XATTR_SIZE(i->value_len) ||
562 free < EXT4_XATTR_LEN(name_len) +
563 EXT4_XATTR_SIZE(i->value_len))
564 return -ENOSPC;
565 }
566
567 if (i->value && s->not_found) {
568 /* Insert the new name. */
569 size_t size = EXT4_XATTR_LEN(name_len);
570 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
571 memmove((void *)s->here + size, s->here, rest);
572 memset(s->here, 0, size);
573 s->here->e_name_index = i->name_index;
574 s->here->e_name_len = name_len;
575 memcpy(s->here->e_name, i->name, name_len);
576 } else {
577 if (!s->here->e_value_block && s->here->e_value_size) {
578 void *first_val = s->base + min_offs;
579 size_t offs = le16_to_cpu(s->here->e_value_offs);
580 void *val = s->base + offs;
581 size_t size = EXT4_XATTR_SIZE(
582 le32_to_cpu(s->here->e_value_size));
583
584 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
585 /* The old and the new value have the same
586 size. Just replace. */
587 s->here->e_value_size =
588 cpu_to_le32(i->value_len);
589 memset(val + size - EXT4_XATTR_PAD, 0,
590 EXT4_XATTR_PAD); /* Clear pad bytes. */
591 memcpy(val, i->value, i->value_len);
592 return 0;
593 }
594
595 /* Remove the old value. */
596 memmove(first_val + size, first_val, val - first_val);
597 memset(first_val, 0, size);
598 s->here->e_value_size = 0;
599 s->here->e_value_offs = 0;
600 min_offs += size;
601
602 /* Adjust all value offsets. */
603 last = s->first;
604 while (!IS_LAST_ENTRY(last)) {
605 size_t o = le16_to_cpu(last->e_value_offs);
606 if (!last->e_value_block &&
607 last->e_value_size && o < offs)
608 last->e_value_offs =
609 cpu_to_le16(o + size);
610 last = EXT4_XATTR_NEXT(last);
611 }
612 }
613 if (!i->value) {
614 /* Remove the old name. */
615 size_t size = EXT4_XATTR_LEN(name_len);
616 last = ENTRY((void *)last - size);
617 memmove(s->here, (void *)s->here + size,
618 (void *)last - (void *)s->here + sizeof(__u32));
619 memset(last, 0, size);
620 }
621 }
622
623 if (i->value) {
624 /* Insert the new value. */
625 s->here->e_value_size = cpu_to_le32(i->value_len);
626 if (i->value_len) {
627 size_t size = EXT4_XATTR_SIZE(i->value_len);
628 void *val = s->base + min_offs - size;
629 s->here->e_value_offs = cpu_to_le16(min_offs - size);
630 memset(val + size - EXT4_XATTR_PAD, 0,
631 EXT4_XATTR_PAD); /* Clear the pad bytes. */
632 memcpy(val, i->value, i->value_len);
633 }
634 }
635 return 0;
636 }
637
638 struct ext4_xattr_block_find {
639 struct ext4_xattr_search s;
640 struct buffer_head *bh;
641 };
642
643 static int
644 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
645 struct ext4_xattr_block_find *bs)
646 {
647 struct super_block *sb = inode->i_sb;
648 int error;
649
650 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
651 i->name_index, i->name, i->value, (long)i->value_len);
652
653 if (EXT4_I(inode)->i_file_acl) {
654 /* The inode already has an extended attribute block. */
655 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
656 error = -EIO;
657 if (!bs->bh)
658 goto cleanup;
659 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
660 atomic_read(&(bs->bh->b_count)),
661 le32_to_cpu(BHDR(bs->bh)->h_refcount));
662 if (ext4_xattr_check_block(bs->bh)) {
663 ext4_error(sb, __FUNCTION__,
664 "inode %lu: bad block %llu", inode->i_ino,
665 EXT4_I(inode)->i_file_acl);
666 error = -EIO;
667 goto cleanup;
668 }
669 /* Find the named attribute. */
670 bs->s.base = BHDR(bs->bh);
671 bs->s.first = BFIRST(bs->bh);
672 bs->s.end = bs->bh->b_data + bs->bh->b_size;
673 bs->s.here = bs->s.first;
674 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
675 i->name, bs->bh->b_size, 1);
676 if (error && error != -ENODATA)
677 goto cleanup;
678 bs->s.not_found = error;
679 }
680 error = 0;
681
682 cleanup:
683 return error;
684 }
685
686 static int
687 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
688 struct ext4_xattr_info *i,
689 struct ext4_xattr_block_find *bs)
690 {
691 struct super_block *sb = inode->i_sb;
692 struct buffer_head *new_bh = NULL;
693 struct ext4_xattr_search *s = &bs->s;
694 struct mb_cache_entry *ce = NULL;
695 int error = 0;
696
697 #define header(x) ((struct ext4_xattr_header *)(x))
698
699 if (i->value && i->value_len > sb->s_blocksize)
700 return -ENOSPC;
701 if (s->base) {
702 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
703 bs->bh->b_blocknr);
704 error = ext4_journal_get_write_access(handle, bs->bh);
705 if (error)
706 goto cleanup;
707 lock_buffer(bs->bh);
708
709 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
710 if (ce) {
711 mb_cache_entry_free(ce);
712 ce = NULL;
713 }
714 ea_bdebug(bs->bh, "modifying in-place");
715 error = ext4_xattr_set_entry(i, s);
716 if (!error) {
717 if (!IS_LAST_ENTRY(s->first))
718 ext4_xattr_rehash(header(s->base),
719 s->here);
720 ext4_xattr_cache_insert(bs->bh);
721 }
722 unlock_buffer(bs->bh);
723 if (error == -EIO)
724 goto bad_block;
725 if (!error)
726 error = ext4_journal_dirty_metadata(handle,
727 bs->bh);
728 if (error)
729 goto cleanup;
730 goto inserted;
731 } else {
732 int offset = (char *)s->here - bs->bh->b_data;
733
734 unlock_buffer(bs->bh);
735 jbd2_journal_release_buffer(handle, bs->bh);
736 if (ce) {
737 mb_cache_entry_release(ce);
738 ce = NULL;
739 }
740 ea_bdebug(bs->bh, "cloning");
741 s->base = kmalloc(bs->bh->b_size, GFP_KERNEL);
742 error = -ENOMEM;
743 if (s->base == NULL)
744 goto cleanup;
745 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
746 s->first = ENTRY(header(s->base)+1);
747 header(s->base)->h_refcount = cpu_to_le32(1);
748 s->here = ENTRY(s->base + offset);
749 s->end = s->base + bs->bh->b_size;
750 }
751 } else {
752 /* Allocate a buffer where we construct the new block. */
753 s->base = kmalloc(sb->s_blocksize, GFP_KERNEL);
754 /* assert(header == s->base) */
755 error = -ENOMEM;
756 if (s->base == NULL)
757 goto cleanup;
758 memset(s->base, 0, sb->s_blocksize);
759 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
760 header(s->base)->h_blocks = cpu_to_le32(1);
761 header(s->base)->h_refcount = cpu_to_le32(1);
762 s->first = ENTRY(header(s->base)+1);
763 s->here = ENTRY(header(s->base)+1);
764 s->end = s->base + sb->s_blocksize;
765 }
766
767 error = ext4_xattr_set_entry(i, s);
768 if (error == -EIO)
769 goto bad_block;
770 if (error)
771 goto cleanup;
772 if (!IS_LAST_ENTRY(s->first))
773 ext4_xattr_rehash(header(s->base), s->here);
774
775 inserted:
776 if (!IS_LAST_ENTRY(s->first)) {
777 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
778 if (new_bh) {
779 /* We found an identical block in the cache. */
780 if (new_bh == bs->bh)
781 ea_bdebug(new_bh, "keeping");
782 else {
783 /* The old block is released after updating
784 the inode. */
785 error = -EDQUOT;
786 if (DQUOT_ALLOC_BLOCK(inode, 1))
787 goto cleanup;
788 error = ext4_journal_get_write_access(handle,
789 new_bh);
790 if (error)
791 goto cleanup_dquot;
792 lock_buffer(new_bh);
793 BHDR(new_bh)->h_refcount = cpu_to_le32(1 +
794 le32_to_cpu(BHDR(new_bh)->h_refcount));
795 ea_bdebug(new_bh, "reusing; refcount now=%d",
796 le32_to_cpu(BHDR(new_bh)->h_refcount));
797 unlock_buffer(new_bh);
798 error = ext4_journal_dirty_metadata(handle,
799 new_bh);
800 if (error)
801 goto cleanup_dquot;
802 }
803 mb_cache_entry_release(ce);
804 ce = NULL;
805 } else if (bs->bh && s->base == bs->bh->b_data) {
806 /* We were modifying this block in-place. */
807 ea_bdebug(bs->bh, "keeping this block");
808 new_bh = bs->bh;
809 get_bh(new_bh);
810 } else {
811 /* We need to allocate a new block */
812 ext4_fsblk_t goal = le32_to_cpu(
813 EXT4_SB(sb)->s_es->s_first_data_block) +
814 (ext4_fsblk_t)EXT4_I(inode)->i_block_group *
815 EXT4_BLOCKS_PER_GROUP(sb);
816 ext4_fsblk_t block = ext4_new_block(handle, inode,
817 goal, &error);
818 if (error)
819 goto cleanup;
820 ea_idebug(inode, "creating block %d", block);
821
822 new_bh = sb_getblk(sb, block);
823 if (!new_bh) {
824 getblk_failed:
825 ext4_free_blocks(handle, inode, block, 1);
826 error = -EIO;
827 goto cleanup;
828 }
829 lock_buffer(new_bh);
830 error = ext4_journal_get_create_access(handle, new_bh);
831 if (error) {
832 unlock_buffer(new_bh);
833 goto getblk_failed;
834 }
835 memcpy(new_bh->b_data, s->base, new_bh->b_size);
836 set_buffer_uptodate(new_bh);
837 unlock_buffer(new_bh);
838 ext4_xattr_cache_insert(new_bh);
839 error = ext4_journal_dirty_metadata(handle, new_bh);
840 if (error)
841 goto cleanup;
842 }
843 }
844
845 /* Update the inode. */
846 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
847
848 /* Drop the previous xattr block. */
849 if (bs->bh && bs->bh != new_bh)
850 ext4_xattr_release_block(handle, inode, bs->bh);
851 error = 0;
852
853 cleanup:
854 if (ce)
855 mb_cache_entry_release(ce);
856 brelse(new_bh);
857 if (!(bs->bh && s->base == bs->bh->b_data))
858 kfree(s->base);
859
860 return error;
861
862 cleanup_dquot:
863 DQUOT_FREE_BLOCK(inode, 1);
864 goto cleanup;
865
866 bad_block:
867 ext4_error(inode->i_sb, __FUNCTION__,
868 "inode %lu: bad block %llu", inode->i_ino,
869 EXT4_I(inode)->i_file_acl);
870 goto cleanup;
871
872 #undef header
873 }
874
875 struct ext4_xattr_ibody_find {
876 struct ext4_xattr_search s;
877 struct ext4_iloc iloc;
878 };
879
880 static int
881 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
882 struct ext4_xattr_ibody_find *is)
883 {
884 struct ext4_xattr_ibody_header *header;
885 struct ext4_inode *raw_inode;
886 int error;
887
888 if (EXT4_I(inode)->i_extra_isize == 0)
889 return 0;
890 raw_inode = ext4_raw_inode(&is->iloc);
891 header = IHDR(inode, raw_inode);
892 is->s.base = is->s.first = IFIRST(header);
893 is->s.here = is->s.first;
894 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
895 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
896 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
897 if (error)
898 return error;
899 /* Find the named attribute. */
900 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
901 i->name, is->s.end -
902 (void *)is->s.base, 0);
903 if (error && error != -ENODATA)
904 return error;
905 is->s.not_found = error;
906 }
907 return 0;
908 }
909
910 static int
911 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
912 struct ext4_xattr_info *i,
913 struct ext4_xattr_ibody_find *is)
914 {
915 struct ext4_xattr_ibody_header *header;
916 struct ext4_xattr_search *s = &is->s;
917 int error;
918
919 if (EXT4_I(inode)->i_extra_isize == 0)
920 return -ENOSPC;
921 error = ext4_xattr_set_entry(i, s);
922 if (error)
923 return error;
924 header = IHDR(inode, ext4_raw_inode(&is->iloc));
925 if (!IS_LAST_ENTRY(s->first)) {
926 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
927 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
928 } else {
929 header->h_magic = cpu_to_le32(0);
930 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
931 }
932 return 0;
933 }
934
935 /*
936 * ext4_xattr_set_handle()
937 *
938 * Create, replace or remove an extended attribute for this inode. Buffer
939 * is NULL to remove an existing extended attribute, and non-NULL to
940 * either replace an existing extended attribute, or create a new extended
941 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
942 * specify that an extended attribute must exist and must not exist
943 * previous to the call, respectively.
944 *
945 * Returns 0, or a negative error number on failure.
946 */
947 int
948 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
949 const char *name, const void *value, size_t value_len,
950 int flags)
951 {
952 struct ext4_xattr_info i = {
953 .name_index = name_index,
954 .name = name,
955 .value = value,
956 .value_len = value_len,
957
958 };
959 struct ext4_xattr_ibody_find is = {
960 .s = { .not_found = -ENODATA, },
961 };
962 struct ext4_xattr_block_find bs = {
963 .s = { .not_found = -ENODATA, },
964 };
965 int error;
966
967 if (!name)
968 return -EINVAL;
969 if (strlen(name) > 255)
970 return -ERANGE;
971 down_write(&EXT4_I(inode)->xattr_sem);
972 error = ext4_get_inode_loc(inode, &is.iloc);
973 if (error)
974 goto cleanup;
975
976 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
977 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
978 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
979 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
980 }
981
982 error = ext4_xattr_ibody_find(inode, &i, &is);
983 if (error)
984 goto cleanup;
985 if (is.s.not_found)
986 error = ext4_xattr_block_find(inode, &i, &bs);
987 if (error)
988 goto cleanup;
989 if (is.s.not_found && bs.s.not_found) {
990 error = -ENODATA;
991 if (flags & XATTR_REPLACE)
992 goto cleanup;
993 error = 0;
994 if (!value)
995 goto cleanup;
996 } else {
997 error = -EEXIST;
998 if (flags & XATTR_CREATE)
999 goto cleanup;
1000 }
1001 error = ext4_journal_get_write_access(handle, is.iloc.bh);
1002 if (error)
1003 goto cleanup;
1004 if (!value) {
1005 if (!is.s.not_found)
1006 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1007 else if (!bs.s.not_found)
1008 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1009 } else {
1010 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1011 if (!error && !bs.s.not_found) {
1012 i.value = NULL;
1013 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1014 } else if (error == -ENOSPC) {
1015 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1016 if (error)
1017 goto cleanup;
1018 if (!is.s.not_found) {
1019 i.value = NULL;
1020 error = ext4_xattr_ibody_set(handle, inode, &i,
1021 &is);
1022 }
1023 }
1024 }
1025 if (!error) {
1026 ext4_xattr_update_super_block(handle, inode->i_sb);
1027 inode->i_ctime = ext4_current_time(inode);
1028 if (!value)
1029 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1030 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1031 /*
1032 * The bh is consumed by ext4_mark_iloc_dirty, even with
1033 * error != 0.
1034 */
1035 is.iloc.bh = NULL;
1036 if (IS_SYNC(inode))
1037 handle->h_sync = 1;
1038 }
1039
1040 cleanup:
1041 brelse(is.iloc.bh);
1042 brelse(bs.bh);
1043 up_write(&EXT4_I(inode)->xattr_sem);
1044 return error;
1045 }
1046
1047 /*
1048 * ext4_xattr_set()
1049 *
1050 * Like ext4_xattr_set_handle, but start from an inode. This extended
1051 * attribute modification is a filesystem transaction by itself.
1052 *
1053 * Returns 0, or a negative error number on failure.
1054 */
1055 int
1056 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1057 const void *value, size_t value_len, int flags)
1058 {
1059 handle_t *handle;
1060 int error, retries = 0;
1061
1062 retry:
1063 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1064 if (IS_ERR(handle)) {
1065 error = PTR_ERR(handle);
1066 } else {
1067 int error2;
1068
1069 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1070 value, value_len, flags);
1071 error2 = ext4_journal_stop(handle);
1072 if (error == -ENOSPC &&
1073 ext4_should_retry_alloc(inode->i_sb, &retries))
1074 goto retry;
1075 if (error == 0)
1076 error = error2;
1077 }
1078
1079 return error;
1080 }
1081
1082 /*
1083 * Shift the EA entries in the inode to create space for the increased
1084 * i_extra_isize.
1085 */
1086 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1087 int value_offs_shift, void *to,
1088 void *from, size_t n, int blocksize)
1089 {
1090 struct ext4_xattr_entry *last = entry;
1091 int new_offs;
1092
1093 /* Adjust the value offsets of the entries */
1094 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1095 if (!last->e_value_block && last->e_value_size) {
1096 new_offs = le16_to_cpu(last->e_value_offs) +
1097 value_offs_shift;
1098 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1099 > blocksize);
1100 last->e_value_offs = cpu_to_le16(new_offs);
1101 }
1102 }
1103 /* Shift the entries by n bytes */
1104 memmove(to, from, n);
1105 }
1106
1107 /*
1108 * Expand an inode by new_extra_isize bytes when EAs are present.
1109 * Returns 0 on success or negative error number on failure.
1110 */
1111 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1112 struct ext4_inode *raw_inode, handle_t *handle)
1113 {
1114 struct ext4_xattr_ibody_header *header;
1115 struct ext4_xattr_entry *entry, *last, *first;
1116 struct buffer_head *bh = NULL;
1117 struct ext4_xattr_ibody_find *is = NULL;
1118 struct ext4_xattr_block_find *bs = NULL;
1119 char *buffer = NULL, *b_entry_name = NULL;
1120 size_t min_offs, free;
1121 int total_ino, total_blk;
1122 void *base, *start, *end;
1123 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1124 int s_min_extra_isize = EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize;
1125
1126 down_write(&EXT4_I(inode)->xattr_sem);
1127 retry:
1128 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1129 up_write(&EXT4_I(inode)->xattr_sem);
1130 return 0;
1131 }
1132
1133 header = IHDR(inode, raw_inode);
1134 entry = IFIRST(header);
1135
1136 /*
1137 * Check if enough free space is available in the inode to shift the
1138 * entries ahead by new_extra_isize.
1139 */
1140
1141 base = start = entry;
1142 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1143 min_offs = end - base;
1144 last = entry;
1145 total_ino = sizeof(struct ext4_xattr_ibody_header);
1146
1147 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1148 if (free >= new_extra_isize) {
1149 entry = IFIRST(header);
1150 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1151 - new_extra_isize, (void *)raw_inode +
1152 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1153 (void *)header, total_ino,
1154 inode->i_sb->s_blocksize);
1155 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1156 error = 0;
1157 goto cleanup;
1158 }
1159
1160 /*
1161 * Enough free space isn't available in the inode, check if
1162 * EA block can hold new_extra_isize bytes.
1163 */
1164 if (EXT4_I(inode)->i_file_acl) {
1165 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1166 error = -EIO;
1167 if (!bh)
1168 goto cleanup;
1169 if (ext4_xattr_check_block(bh)) {
1170 ext4_error(inode->i_sb, __FUNCTION__,
1171 "inode %lu: bad block %llu", inode->i_ino,
1172 EXT4_I(inode)->i_file_acl);
1173 error = -EIO;
1174 goto cleanup;
1175 }
1176 base = BHDR(bh);
1177 first = BFIRST(bh);
1178 end = bh->b_data + bh->b_size;
1179 min_offs = end - base;
1180 free = ext4_xattr_free_space(first, &min_offs, base,
1181 &total_blk);
1182 if (free < new_extra_isize) {
1183 if (!tried_min_extra_isize && s_min_extra_isize) {
1184 tried_min_extra_isize++;
1185 new_extra_isize = s_min_extra_isize;
1186 brelse(bh);
1187 goto retry;
1188 }
1189 error = -1;
1190 goto cleanup;
1191 }
1192 } else {
1193 free = inode->i_sb->s_blocksize;
1194 }
1195
1196 while (new_extra_isize > 0) {
1197 size_t offs, size, entry_size;
1198 struct ext4_xattr_entry *small_entry = NULL;
1199 struct ext4_xattr_info i = {
1200 .value = NULL,
1201 .value_len = 0,
1202 };
1203 unsigned int total_size; /* EA entry size + value size */
1204 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1205 unsigned int min_total_size = ~0U;
1206
1207 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1208 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1209 if (!is || !bs) {
1210 error = -ENOMEM;
1211 goto cleanup;
1212 }
1213
1214 is->s.not_found = -ENODATA;
1215 bs->s.not_found = -ENODATA;
1216 is->iloc.bh = NULL;
1217 bs->bh = NULL;
1218
1219 last = IFIRST(header);
1220 /* Find the entry best suited to be pushed into EA block */
1221 entry = NULL;
1222 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1223 total_size =
1224 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1225 EXT4_XATTR_LEN(last->e_name_len);
1226 if (total_size <= free && total_size < min_total_size) {
1227 if (total_size < new_extra_isize) {
1228 small_entry = last;
1229 } else {
1230 entry = last;
1231 min_total_size = total_size;
1232 }
1233 }
1234 }
1235
1236 if (entry == NULL) {
1237 if (small_entry) {
1238 entry = small_entry;
1239 } else {
1240 if (!tried_min_extra_isize &&
1241 s_min_extra_isize) {
1242 tried_min_extra_isize++;
1243 new_extra_isize = s_min_extra_isize;
1244 goto retry;
1245 }
1246 error = -1;
1247 goto cleanup;
1248 }
1249 }
1250 offs = le16_to_cpu(entry->e_value_offs);
1251 size = le32_to_cpu(entry->e_value_size);
1252 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1253 i.name_index = entry->e_name_index,
1254 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1255 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1256 if (!buffer || !b_entry_name) {
1257 error = -ENOMEM;
1258 goto cleanup;
1259 }
1260 /* Save the entry name and the entry value */
1261 memcpy(buffer, (void *)IFIRST(header) + offs,
1262 EXT4_XATTR_SIZE(size));
1263 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1264 b_entry_name[entry->e_name_len] = '\0';
1265 i.name = b_entry_name;
1266
1267 error = ext4_get_inode_loc(inode, &is->iloc);
1268 if (error)
1269 goto cleanup;
1270
1271 error = ext4_xattr_ibody_find(inode, &i, is);
1272 if (error)
1273 goto cleanup;
1274
1275 /* Remove the chosen entry from the inode */
1276 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1277
1278 entry = IFIRST(header);
1279 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1280 shift_bytes = new_extra_isize;
1281 else
1282 shift_bytes = entry_size + size;
1283 /* Adjust the offsets and shift the remaining entries ahead */
1284 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1285 shift_bytes, (void *)raw_inode +
1286 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1287 (void *)header, total_ino - entry_size,
1288 inode->i_sb->s_blocksize);
1289
1290 extra_isize += shift_bytes;
1291 new_extra_isize -= shift_bytes;
1292 EXT4_I(inode)->i_extra_isize = extra_isize;
1293
1294 i.name = b_entry_name;
1295 i.value = buffer;
1296 i.value_len = cpu_to_le32(size);
1297 error = ext4_xattr_block_find(inode, &i, bs);
1298 if (error)
1299 goto cleanup;
1300
1301 /* Add entry which was removed from the inode into the block */
1302 error = ext4_xattr_block_set(handle, inode, &i, bs);
1303 if (error)
1304 goto cleanup;
1305 kfree(b_entry_name);
1306 kfree(buffer);
1307 brelse(is->iloc.bh);
1308 kfree(is);
1309 kfree(bs);
1310 }
1311 brelse(bh);
1312 up_write(&EXT4_I(inode)->xattr_sem);
1313 return 0;
1314
1315 cleanup:
1316 kfree(b_entry_name);
1317 kfree(buffer);
1318 if (is)
1319 brelse(is->iloc.bh);
1320 kfree(is);
1321 kfree(bs);
1322 brelse(bh);
1323 up_write(&EXT4_I(inode)->xattr_sem);
1324 return error;
1325 }
1326
1327
1328
1329 /*
1330 * ext4_xattr_delete_inode()
1331 *
1332 * Free extended attribute resources associated with this inode. This
1333 * is called immediately before an inode is freed. We have exclusive
1334 * access to the inode.
1335 */
1336 void
1337 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1338 {
1339 struct buffer_head *bh = NULL;
1340
1341 if (!EXT4_I(inode)->i_file_acl)
1342 goto cleanup;
1343 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1344 if (!bh) {
1345 ext4_error(inode->i_sb, __FUNCTION__,
1346 "inode %lu: block %llu read error", inode->i_ino,
1347 EXT4_I(inode)->i_file_acl);
1348 goto cleanup;
1349 }
1350 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1351 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1352 ext4_error(inode->i_sb, __FUNCTION__,
1353 "inode %lu: bad block %llu", inode->i_ino,
1354 EXT4_I(inode)->i_file_acl);
1355 goto cleanup;
1356 }
1357 ext4_xattr_release_block(handle, inode, bh);
1358 EXT4_I(inode)->i_file_acl = 0;
1359
1360 cleanup:
1361 brelse(bh);
1362 }
1363
1364 /*
1365 * ext4_xattr_put_super()
1366 *
1367 * This is called when a file system is unmounted.
1368 */
1369 void
1370 ext4_xattr_put_super(struct super_block *sb)
1371 {
1372 mb_cache_shrink(sb->s_bdev);
1373 }
1374
1375 /*
1376 * ext4_xattr_cache_insert()
1377 *
1378 * Create a new entry in the extended attribute cache, and insert
1379 * it unless such an entry is already in the cache.
1380 *
1381 * Returns 0, or a negative error number on failure.
1382 */
1383 static void
1384 ext4_xattr_cache_insert(struct buffer_head *bh)
1385 {
1386 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1387 struct mb_cache_entry *ce;
1388 int error;
1389
1390 ce = mb_cache_entry_alloc(ext4_xattr_cache);
1391 if (!ce) {
1392 ea_bdebug(bh, "out of memory");
1393 return;
1394 }
1395 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1396 if (error) {
1397 mb_cache_entry_free(ce);
1398 if (error == -EBUSY) {
1399 ea_bdebug(bh, "already in cache");
1400 error = 0;
1401 }
1402 } else {
1403 ea_bdebug(bh, "inserting [%x]", (int)hash);
1404 mb_cache_entry_release(ce);
1405 }
1406 }
1407
1408 /*
1409 * ext4_xattr_cmp()
1410 *
1411 * Compare two extended attribute blocks for equality.
1412 *
1413 * Returns 0 if the blocks are equal, 1 if they differ, and
1414 * a negative error number on errors.
1415 */
1416 static int
1417 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1418 struct ext4_xattr_header *header2)
1419 {
1420 struct ext4_xattr_entry *entry1, *entry2;
1421
1422 entry1 = ENTRY(header1+1);
1423 entry2 = ENTRY(header2+1);
1424 while (!IS_LAST_ENTRY(entry1)) {
1425 if (IS_LAST_ENTRY(entry2))
1426 return 1;
1427 if (entry1->e_hash != entry2->e_hash ||
1428 entry1->e_name_index != entry2->e_name_index ||
1429 entry1->e_name_len != entry2->e_name_len ||
1430 entry1->e_value_size != entry2->e_value_size ||
1431 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1432 return 1;
1433 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1434 return -EIO;
1435 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1436 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1437 le32_to_cpu(entry1->e_value_size)))
1438 return 1;
1439
1440 entry1 = EXT4_XATTR_NEXT(entry1);
1441 entry2 = EXT4_XATTR_NEXT(entry2);
1442 }
1443 if (!IS_LAST_ENTRY(entry2))
1444 return 1;
1445 return 0;
1446 }
1447
1448 /*
1449 * ext4_xattr_cache_find()
1450 *
1451 * Find an identical extended attribute block.
1452 *
1453 * Returns a pointer to the block found, or NULL if such a block was
1454 * not found or an error occurred.
1455 */
1456 static struct buffer_head *
1457 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1458 struct mb_cache_entry **pce)
1459 {
1460 __u32 hash = le32_to_cpu(header->h_hash);
1461 struct mb_cache_entry *ce;
1462
1463 if (!header->h_hash)
1464 return NULL; /* never share */
1465 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1466 again:
1467 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1468 inode->i_sb->s_bdev, hash);
1469 while (ce) {
1470 struct buffer_head *bh;
1471
1472 if (IS_ERR(ce)) {
1473 if (PTR_ERR(ce) == -EAGAIN)
1474 goto again;
1475 break;
1476 }
1477 bh = sb_bread(inode->i_sb, ce->e_block);
1478 if (!bh) {
1479 ext4_error(inode->i_sb, __FUNCTION__,
1480 "inode %lu: block %lu read error",
1481 inode->i_ino, (unsigned long) ce->e_block);
1482 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1483 EXT4_XATTR_REFCOUNT_MAX) {
1484 ea_idebug(inode, "block %lu refcount %d>=%d",
1485 (unsigned long) ce->e_block,
1486 le32_to_cpu(BHDR(bh)->h_refcount),
1487 EXT4_XATTR_REFCOUNT_MAX);
1488 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1489 *pce = ce;
1490 return bh;
1491 }
1492 brelse(bh);
1493 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1494 }
1495 return NULL;
1496 }
1497
1498 #define NAME_HASH_SHIFT 5
1499 #define VALUE_HASH_SHIFT 16
1500
1501 /*
1502 * ext4_xattr_hash_entry()
1503 *
1504 * Compute the hash of an extended attribute.
1505 */
1506 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1507 struct ext4_xattr_entry *entry)
1508 {
1509 __u32 hash = 0;
1510 char *name = entry->e_name;
1511 int n;
1512
1513 for (n=0; n < entry->e_name_len; n++) {
1514 hash = (hash << NAME_HASH_SHIFT) ^
1515 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1516 *name++;
1517 }
1518
1519 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1520 __le32 *value = (__le32 *)((char *)header +
1521 le16_to_cpu(entry->e_value_offs));
1522 for (n = (le32_to_cpu(entry->e_value_size) +
1523 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1524 hash = (hash << VALUE_HASH_SHIFT) ^
1525 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1526 le32_to_cpu(*value++);
1527 }
1528 }
1529 entry->e_hash = cpu_to_le32(hash);
1530 }
1531
1532 #undef NAME_HASH_SHIFT
1533 #undef VALUE_HASH_SHIFT
1534
1535 #define BLOCK_HASH_SHIFT 16
1536
1537 /*
1538 * ext4_xattr_rehash()
1539 *
1540 * Re-compute the extended attribute hash value after an entry has changed.
1541 */
1542 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1543 struct ext4_xattr_entry *entry)
1544 {
1545 struct ext4_xattr_entry *here;
1546 __u32 hash = 0;
1547
1548 ext4_xattr_hash_entry(header, entry);
1549 here = ENTRY(header+1);
1550 while (!IS_LAST_ENTRY(here)) {
1551 if (!here->e_hash) {
1552 /* Block is not shared if an entry's hash value == 0 */
1553 hash = 0;
1554 break;
1555 }
1556 hash = (hash << BLOCK_HASH_SHIFT) ^
1557 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1558 le32_to_cpu(here->e_hash);
1559 here = EXT4_XATTR_NEXT(here);
1560 }
1561 header->h_hash = cpu_to_le32(hash);
1562 }
1563
1564 #undef BLOCK_HASH_SHIFT
1565
1566 int __init
1567 init_ext4_xattr(void)
1568 {
1569 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1570 sizeof(struct mb_cache_entry) +
1571 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1572 if (!ext4_xattr_cache)
1573 return -ENOMEM;
1574 return 0;
1575 }
1576
1577 void
1578 exit_ext4_xattr(void)
1579 {
1580 if (ext4_xattr_cache)
1581 mb_cache_destroy(ext4_xattr_cache);
1582 ext4_xattr_cache = NULL;
1583 }
Linux kernel - Deliverables
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