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xfs: simplify xfs_qm_dqattach_grouphint
[linux-2.6/cjktty.git] / fs / ext4 / xattr.c
blob93a00d89a220d4085c64e9d427c375e9ada76494
1 /*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16 /*
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53 #include <linux/init.h>
54 #include <linux/fs.h>
55 #include <linux/slab.h>
56 #include <linux/mbcache.h>
57 #include <linux/quotaops.h>
58 #include <linux/rwsem.h>
59 #include "ext4_jbd2.h"
60 #include "ext4.h"
61 #include "xattr.h"
62 #include "acl.h"
63
64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
68
69 #ifdef EXT4_XATTR_DEBUG
70 # define ea_idebug(inode, f...) do { \
71 printk(KERN_DEBUG "inode %s:%lu: ", \
72 inode->i_sb->s_id, inode->i_ino); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76 # define ea_bdebug(bh, f...) do { \
77 char b[BDEVNAME_SIZE]; \
78 printk(KERN_DEBUG "block %s:%lu: ", \
79 bdevname(bh->b_bdev, b), \
80 (unsigned long) bh->b_blocknr); \
81 printk(f); \
82 printk("\n"); \
83 } while (0)
84 #else
85 # define ea_idebug(f...)
86 # define ea_bdebug(f...)
87 #endif
88
89 static void ext4_xattr_cache_insert(struct buffer_head *);
90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
91 struct ext4_xattr_header *,
92 struct mb_cache_entry **);
93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
94 struct ext4_xattr_entry *);
95 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
96 size_t buffer_size);
97
98 static struct mb_cache *ext4_xattr_cache;
99
100 static const struct xattr_handler *ext4_xattr_handler_map[] = {
101 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
103 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
104 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
105 #endif
106 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
107 #ifdef CONFIG_EXT4_FS_SECURITY
108 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
109 #endif
110 };
111
112 const struct xattr_handler *ext4_xattr_handlers[] = {
113 &ext4_xattr_user_handler,
114 &ext4_xattr_trusted_handler,
115 #ifdef CONFIG_EXT4_FS_POSIX_ACL
116 &ext4_xattr_acl_access_handler,
117 &ext4_xattr_acl_default_handler,
118 #endif
119 #ifdef CONFIG_EXT4_FS_SECURITY
120 &ext4_xattr_security_handler,
121 #endif
122 NULL
123 };
124
125 static inline const struct xattr_handler *
126 ext4_xattr_handler(int name_index)
127 {
128 const struct xattr_handler *handler = NULL;
129
130 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
131 handler = ext4_xattr_handler_map[name_index];
132 return handler;
133 }
134
135 /*
136 * Inode operation listxattr()
137 *
138 * dentry->d_inode->i_mutex: don't care
139 */
140 ssize_t
141 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
142 {
143 return ext4_xattr_list(dentry, buffer, size);
144 }
145
146 static int
147 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
148 {
149 while (!IS_LAST_ENTRY(entry)) {
150 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
151 if ((void *)next >= end)
152 return -EIO;
153 entry = next;
154 }
155 return 0;
156 }
157
158 static inline int
159 ext4_xattr_check_block(struct buffer_head *bh)
160 {
161 int error;
162
163 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
164 BHDR(bh)->h_blocks != cpu_to_le32(1))
165 return -EIO;
166 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
167 return error;
168 }
169
170 static inline int
171 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
172 {
173 size_t value_size = le32_to_cpu(entry->e_value_size);
174
175 if (entry->e_value_block != 0 || value_size > size ||
176 le16_to_cpu(entry->e_value_offs) + value_size > size)
177 return -EIO;
178 return 0;
179 }
180
181 static int
182 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
183 const char *name, size_t size, int sorted)
184 {
185 struct ext4_xattr_entry *entry;
186 size_t name_len;
187 int cmp = 1;
188
189 if (name == NULL)
190 return -EINVAL;
191 name_len = strlen(name);
192 entry = *pentry;
193 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
194 cmp = name_index - entry->e_name_index;
195 if (!cmp)
196 cmp = name_len - entry->e_name_len;
197 if (!cmp)
198 cmp = memcmp(name, entry->e_name, name_len);
199 if (cmp <= 0 && (sorted || cmp == 0))
200 break;
201 }
202 *pentry = entry;
203 if (!cmp && ext4_xattr_check_entry(entry, size))
204 return -EIO;
205 return cmp ? -ENODATA : 0;
206 }
207
208 static int
209 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
210 void *buffer, size_t buffer_size)
211 {
212 struct buffer_head *bh = NULL;
213 struct ext4_xattr_entry *entry;
214 size_t size;
215 int error;
216
217 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
218 name_index, name, buffer, (long)buffer_size);
219
220 error = -ENODATA;
221 if (!EXT4_I(inode)->i_file_acl)
222 goto cleanup;
223 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
224 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
225 if (!bh)
226 goto cleanup;
227 ea_bdebug(bh, "b_count=%d, refcount=%d",
228 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
229 if (ext4_xattr_check_block(bh)) {
230 bad_block:
231 EXT4_ERROR_INODE(inode, "bad block %llu",
232 EXT4_I(inode)->i_file_acl);
233 error = -EIO;
234 goto cleanup;
235 }
236 ext4_xattr_cache_insert(bh);
237 entry = BFIRST(bh);
238 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
239 if (error == -EIO)
240 goto bad_block;
241 if (error)
242 goto cleanup;
243 size = le32_to_cpu(entry->e_value_size);
244 if (buffer) {
245 error = -ERANGE;
246 if (size > buffer_size)
247 goto cleanup;
248 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
249 size);
250 }
251 error = size;
252
253 cleanup:
254 brelse(bh);
255 return error;
256 }
257
258 static int
259 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
260 void *buffer, size_t buffer_size)
261 {
262 struct ext4_xattr_ibody_header *header;
263 struct ext4_xattr_entry *entry;
264 struct ext4_inode *raw_inode;
265 struct ext4_iloc iloc;
266 size_t size;
267 void *end;
268 int error;
269
270 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
271 return -ENODATA;
272 error = ext4_get_inode_loc(inode, &iloc);
273 if (error)
274 return error;
275 raw_inode = ext4_raw_inode(&iloc);
276 header = IHDR(inode, raw_inode);
277 entry = IFIRST(header);
278 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
279 error = ext4_xattr_check_names(entry, end);
280 if (error)
281 goto cleanup;
282 error = ext4_xattr_find_entry(&entry, name_index, name,
283 end - (void *)entry, 0);
284 if (error)
285 goto cleanup;
286 size = le32_to_cpu(entry->e_value_size);
287 if (buffer) {
288 error = -ERANGE;
289 if (size > buffer_size)
290 goto cleanup;
291 memcpy(buffer, (void *)IFIRST(header) +
292 le16_to_cpu(entry->e_value_offs), size);
293 }
294 error = size;
295
296 cleanup:
297 brelse(iloc.bh);
298 return error;
299 }
300
301 /*
302 * ext4_xattr_get()
303 *
304 * Copy an extended attribute into the buffer
305 * provided, or compute the buffer size required.
306 * Buffer is NULL to compute the size of the buffer required.
307 *
308 * Returns a negative error number on failure, or the number of bytes
309 * used / required on success.
310 */
311 int
312 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
313 void *buffer, size_t buffer_size)
314 {
315 int error;
316
317 down_read(&EXT4_I(inode)->xattr_sem);
318 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
319 buffer_size);
320 if (error == -ENODATA)
321 error = ext4_xattr_block_get(inode, name_index, name, buffer,
322 buffer_size);
323 up_read(&EXT4_I(inode)->xattr_sem);
324 return error;
325 }
326
327 static int
328 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
329 char *buffer, size_t buffer_size)
330 {
331 size_t rest = buffer_size;
332
333 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
334 const struct xattr_handler *handler =
335 ext4_xattr_handler(entry->e_name_index);
336
337 if (handler) {
338 size_t size = handler->list(dentry, buffer, rest,
339 entry->e_name,
340 entry->e_name_len,
341 handler->flags);
342 if (buffer) {
343 if (size > rest)
344 return -ERANGE;
345 buffer += size;
346 }
347 rest -= size;
348 }
349 }
350 return buffer_size - rest;
351 }
352
353 static int
354 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
355 {
356 struct inode *inode = dentry->d_inode;
357 struct buffer_head *bh = NULL;
358 int error;
359
360 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
361 buffer, (long)buffer_size);
362
363 error = 0;
364 if (!EXT4_I(inode)->i_file_acl)
365 goto cleanup;
366 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
367 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
368 error = -EIO;
369 if (!bh)
370 goto cleanup;
371 ea_bdebug(bh, "b_count=%d, refcount=%d",
372 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
373 if (ext4_xattr_check_block(bh)) {
374 EXT4_ERROR_INODE(inode, "bad block %llu",
375 EXT4_I(inode)->i_file_acl);
376 error = -EIO;
377 goto cleanup;
378 }
379 ext4_xattr_cache_insert(bh);
380 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
381
382 cleanup:
383 brelse(bh);
384
385 return error;
386 }
387
388 static int
389 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
390 {
391 struct inode *inode = dentry->d_inode;
392 struct ext4_xattr_ibody_header *header;
393 struct ext4_inode *raw_inode;
394 struct ext4_iloc iloc;
395 void *end;
396 int error;
397
398 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
399 return 0;
400 error = ext4_get_inode_loc(inode, &iloc);
401 if (error)
402 return error;
403 raw_inode = ext4_raw_inode(&iloc);
404 header = IHDR(inode, raw_inode);
405 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
406 error = ext4_xattr_check_names(IFIRST(header), end);
407 if (error)
408 goto cleanup;
409 error = ext4_xattr_list_entries(dentry, IFIRST(header),
410 buffer, buffer_size);
411
412 cleanup:
413 brelse(iloc.bh);
414 return error;
415 }
416
417 /*
418 * ext4_xattr_list()
419 *
420 * Copy a list of attribute names into the buffer
421 * provided, or compute the buffer size required.
422 * Buffer is NULL to compute the size of the buffer required.
423 *
424 * Returns a negative error number on failure, or the number of bytes
425 * used / required on success.
426 */
427 static int
428 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
429 {
430 int ret, ret2;
431
432 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
433 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
434 if (ret < 0)
435 goto errout;
436 if (buffer) {
437 buffer += ret;
438 buffer_size -= ret;
439 }
440 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
441 if (ret < 0)
442 goto errout;
443 ret += ret2;
444 errout:
445 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
446 return ret;
447 }
448
449 /*
450 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
451 * not set, set it.
452 */
453 static void ext4_xattr_update_super_block(handle_t *handle,
454 struct super_block *sb)
455 {
456 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
457 return;
458
459 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
460 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
461 ext4_handle_dirty_super(handle, sb);
462 }
463 }
464
465 /*
466 * Release the xattr block BH: If the reference count is > 1, decrement
467 * it; otherwise free the block.
468 */
469 static void
470 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
471 struct buffer_head *bh)
472 {
473 struct mb_cache_entry *ce = NULL;
474 int error = 0;
475
476 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
477 error = ext4_journal_get_write_access(handle, bh);
478 if (error)
479 goto out;
480
481 lock_buffer(bh);
482 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
483 ea_bdebug(bh, "refcount now=0; freeing");
484 if (ce)
485 mb_cache_entry_free(ce);
486 get_bh(bh);
487 ext4_free_blocks(handle, inode, bh, 0, 1,
488 EXT4_FREE_BLOCKS_METADATA |
489 EXT4_FREE_BLOCKS_FORGET);
490 } else {
491 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
492 error = ext4_handle_dirty_metadata(handle, inode, bh);
493 if (IS_SYNC(inode))
494 ext4_handle_sync(handle);
495 dquot_free_block(inode, 1);
496 ea_bdebug(bh, "refcount now=%d; releasing",
497 le32_to_cpu(BHDR(bh)->h_refcount));
498 if (ce)
499 mb_cache_entry_release(ce);
500 }
501 unlock_buffer(bh);
502 out:
503 ext4_std_error(inode->i_sb, error);
504 return;
505 }
506
507 /*
508 * Find the available free space for EAs. This also returns the total number of
509 * bytes used by EA entries.
510 */
511 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
512 size_t *min_offs, void *base, int *total)
513 {
514 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
515 *total += EXT4_XATTR_LEN(last->e_name_len);
516 if (!last->e_value_block && last->e_value_size) {
517 size_t offs = le16_to_cpu(last->e_value_offs);
518 if (offs < *min_offs)
519 *min_offs = offs;
520 }
521 }
522 return (*min_offs - ((void *)last - base) - sizeof(__u32));
523 }
524
525 struct ext4_xattr_info {
526 int name_index;
527 const char *name;
528 const void *value;
529 size_t value_len;
530 };
531
532 struct ext4_xattr_search {
533 struct ext4_xattr_entry *first;
534 void *base;
535 void *end;
536 struct ext4_xattr_entry *here;
537 int not_found;
538 };
539
540 static int
541 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
542 {
543 struct ext4_xattr_entry *last;
544 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
545
546 /* Compute min_offs and last. */
547 last = s->first;
548 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
549 if (!last->e_value_block && last->e_value_size) {
550 size_t offs = le16_to_cpu(last->e_value_offs);
551 if (offs < min_offs)
552 min_offs = offs;
553 }
554 }
555 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
556 if (!s->not_found) {
557 if (!s->here->e_value_block && s->here->e_value_size) {
558 size_t size = le32_to_cpu(s->here->e_value_size);
559 free += EXT4_XATTR_SIZE(size);
560 }
561 free += EXT4_XATTR_LEN(name_len);
562 }
563 if (i->value) {
564 if (free < EXT4_XATTR_SIZE(i->value_len) ||
565 free < EXT4_XATTR_LEN(name_len) +
566 EXT4_XATTR_SIZE(i->value_len))
567 return -ENOSPC;
568 }
569
570 if (i->value && s->not_found) {
571 /* Insert the new name. */
572 size_t size = EXT4_XATTR_LEN(name_len);
573 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
574 memmove((void *)s->here + size, s->here, rest);
575 memset(s->here, 0, size);
576 s->here->e_name_index = i->name_index;
577 s->here->e_name_len = name_len;
578 memcpy(s->here->e_name, i->name, name_len);
579 } else {
580 if (!s->here->e_value_block && s->here->e_value_size) {
581 void *first_val = s->base + min_offs;
582 size_t offs = le16_to_cpu(s->here->e_value_offs);
583 void *val = s->base + offs;
584 size_t size = EXT4_XATTR_SIZE(
585 le32_to_cpu(s->here->e_value_size));
586
587 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
588 /* The old and the new value have the same
589 size. Just replace. */
590 s->here->e_value_size =
591 cpu_to_le32(i->value_len);
592 memset(val + size - EXT4_XATTR_PAD, 0,
593 EXT4_XATTR_PAD); /* Clear pad bytes. */
594 memcpy(val, i->value, i->value_len);
595 return 0;
596 }
597
598 /* Remove the old value. */
599 memmove(first_val + size, first_val, val - first_val);
600 memset(first_val, 0, size);
601 s->here->e_value_size = 0;
602 s->here->e_value_offs = 0;
603 min_offs += size;
604
605 /* Adjust all value offsets. */
606 last = s->first;
607 while (!IS_LAST_ENTRY(last)) {
608 size_t o = le16_to_cpu(last->e_value_offs);
609 if (!last->e_value_block &&
610 last->e_value_size && o < offs)
611 last->e_value_offs =
612 cpu_to_le16(o + size);
613 last = EXT4_XATTR_NEXT(last);
614 }
615 }
616 if (!i->value) {
617 /* Remove the old name. */
618 size_t size = EXT4_XATTR_LEN(name_len);
619 last = ENTRY((void *)last - size);
620 memmove(s->here, (void *)s->here + size,
621 (void *)last - (void *)s->here + sizeof(__u32));
622 memset(last, 0, size);
623 }
624 }
625
626 if (i->value) {
627 /* Insert the new value. */
628 s->here->e_value_size = cpu_to_le32(i->value_len);
629 if (i->value_len) {
630 size_t size = EXT4_XATTR_SIZE(i->value_len);
631 void *val = s->base + min_offs - size;
632 s->here->e_value_offs = cpu_to_le16(min_offs - size);
633 memset(val + size - EXT4_XATTR_PAD, 0,
634 EXT4_XATTR_PAD); /* Clear the pad bytes. */
635 memcpy(val, i->value, i->value_len);
636 }
637 }
638 return 0;
639 }
640
641 struct ext4_xattr_block_find {
642 struct ext4_xattr_search s;
643 struct buffer_head *bh;
644 };
645
646 static int
647 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
648 struct ext4_xattr_block_find *bs)
649 {
650 struct super_block *sb = inode->i_sb;
651 int error;
652
653 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
654 i->name_index, i->name, i->value, (long)i->value_len);
655
656 if (EXT4_I(inode)->i_file_acl) {
657 /* The inode already has an extended attribute block. */
658 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
659 error = -EIO;
660 if (!bs->bh)
661 goto cleanup;
662 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
663 atomic_read(&(bs->bh->b_count)),
664 le32_to_cpu(BHDR(bs->bh)->h_refcount));
665 if (ext4_xattr_check_block(bs->bh)) {
666 EXT4_ERROR_INODE(inode, "bad block %llu",
667 EXT4_I(inode)->i_file_acl);
668 error = -EIO;
669 goto cleanup;
670 }
671 /* Find the named attribute. */
672 bs->s.base = BHDR(bs->bh);
673 bs->s.first = BFIRST(bs->bh);
674 bs->s.end = bs->bh->b_data + bs->bh->b_size;
675 bs->s.here = bs->s.first;
676 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
677 i->name, bs->bh->b_size, 1);
678 if (error && error != -ENODATA)
679 goto cleanup;
680 bs->s.not_found = error;
681 }
682 error = 0;
683
684 cleanup:
685 return error;
686 }
687
688 static int
689 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
690 struct ext4_xattr_info *i,
691 struct ext4_xattr_block_find *bs)
692 {
693 struct super_block *sb = inode->i_sb;
694 struct buffer_head *new_bh = NULL;
695 struct ext4_xattr_search *s = &bs->s;
696 struct mb_cache_entry *ce = NULL;
697 int error = 0;
698
699 #define header(x) ((struct ext4_xattr_header *)(x))
700
701 if (i->value && i->value_len > sb->s_blocksize)
702 return -ENOSPC;
703 if (s->base) {
704 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
705 bs->bh->b_blocknr);
706 error = ext4_journal_get_write_access(handle, bs->bh);
707 if (error)
708 goto cleanup;
709 lock_buffer(bs->bh);
710
711 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
712 if (ce) {
713 mb_cache_entry_free(ce);
714 ce = NULL;
715 }
716 ea_bdebug(bs->bh, "modifying in-place");
717 error = ext4_xattr_set_entry(i, s);
718 if (!error) {
719 if (!IS_LAST_ENTRY(s->first))
720 ext4_xattr_rehash(header(s->base),
721 s->here);
722 ext4_xattr_cache_insert(bs->bh);
723 }
724 unlock_buffer(bs->bh);
725 if (error == -EIO)
726 goto bad_block;
727 if (!error)
728 error = ext4_handle_dirty_metadata(handle,
729 inode,
730 bs->bh);
731 if (error)
732 goto cleanup;
733 goto inserted;
734 } else {
735 int offset = (char *)s->here - bs->bh->b_data;
736
737 unlock_buffer(bs->bh);
738 ext4_handle_release_buffer(handle, bs->bh);
739 if (ce) {
740 mb_cache_entry_release(ce);
741 ce = NULL;
742 }
743 ea_bdebug(bs->bh, "cloning");
744 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
745 error = -ENOMEM;
746 if (s->base == NULL)
747 goto cleanup;
748 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
749 s->first = ENTRY(header(s->base)+1);
750 header(s->base)->h_refcount = cpu_to_le32(1);
751 s->here = ENTRY(s->base + offset);
752 s->end = s->base + bs->bh->b_size;
753 }
754 } else {
755 /* Allocate a buffer where we construct the new block. */
756 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
757 /* assert(header == s->base) */
758 error = -ENOMEM;
759 if (s->base == NULL)
760 goto cleanup;
761 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
762 header(s->base)->h_blocks = cpu_to_le32(1);
763 header(s->base)->h_refcount = cpu_to_le32(1);
764 s->first = ENTRY(header(s->base)+1);
765 s->here = ENTRY(header(s->base)+1);
766 s->end = s->base + sb->s_blocksize;
767 }
768
769 error = ext4_xattr_set_entry(i, s);
770 if (error == -EIO)
771 goto bad_block;
772 if (error)
773 goto cleanup;
774 if (!IS_LAST_ENTRY(s->first))
775 ext4_xattr_rehash(header(s->base), s->here);
776
777 inserted:
778 if (!IS_LAST_ENTRY(s->first)) {
779 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
780 if (new_bh) {
781 /* We found an identical block in the cache. */
782 if (new_bh == bs->bh)
783 ea_bdebug(new_bh, "keeping");
784 else {
785 /* The old block is released after updating
786 the inode. */
787 error = dquot_alloc_block(inode, 1);
788 if (error)
789 goto cleanup;
790 error = ext4_journal_get_write_access(handle,
791 new_bh);
792 if (error)
793 goto cleanup_dquot;
794 lock_buffer(new_bh);
795 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
796 ea_bdebug(new_bh, "reusing; refcount now=%d",
797 le32_to_cpu(BHDR(new_bh)->h_refcount));
798 unlock_buffer(new_bh);
799 error = ext4_handle_dirty_metadata(handle,
800 inode,
801 new_bh);
802 if (error)
803 goto cleanup_dquot;
804 }
805 mb_cache_entry_release(ce);
806 ce = NULL;
807 } else if (bs->bh && s->base == bs->bh->b_data) {
808 /* We were modifying this block in-place. */
809 ea_bdebug(bs->bh, "keeping this block");
810 new_bh = bs->bh;
811 get_bh(new_bh);
812 } else {
813 /* We need to allocate a new block */
814 ext4_fsblk_t goal, block;
815
816 goal = ext4_group_first_block_no(sb,
817 EXT4_I(inode)->i_block_group);
818
819 /* non-extent files can't have physical blocks past 2^32 */
820 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
821 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
822
823 /*
824 * take i_data_sem because we will test
825 * i_delalloc_reserved_flag in ext4_mb_new_blocks
826 */
827 down_read((&EXT4_I(inode)->i_data_sem));
828 block = ext4_new_meta_blocks(handle, inode, goal, 0,
829 NULL, &error);
830 up_read((&EXT4_I(inode)->i_data_sem));
831 if (error)
832 goto cleanup;
833
834 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
835 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
836
837 ea_idebug(inode, "creating block %d", block);
838
839 new_bh = sb_getblk(sb, block);
840 if (!new_bh) {
841 getblk_failed:
842 ext4_free_blocks(handle, inode, NULL, block, 1,
843 EXT4_FREE_BLOCKS_METADATA);
844 error = -EIO;
845 goto cleanup;
846 }
847 lock_buffer(new_bh);
848 error = ext4_journal_get_create_access(handle, new_bh);
849 if (error) {
850 unlock_buffer(new_bh);
851 goto getblk_failed;
852 }
853 memcpy(new_bh->b_data, s->base, new_bh->b_size);
854 set_buffer_uptodate(new_bh);
855 unlock_buffer(new_bh);
856 ext4_xattr_cache_insert(new_bh);
857 error = ext4_handle_dirty_metadata(handle,
858 inode, new_bh);
859 if (error)
860 goto cleanup;
861 }
862 }
863
864 /* Update the inode. */
865 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
866
867 /* Drop the previous xattr block. */
868 if (bs->bh && bs->bh != new_bh)
869 ext4_xattr_release_block(handle, inode, bs->bh);
870 error = 0;
871
872 cleanup:
873 if (ce)
874 mb_cache_entry_release(ce);
875 brelse(new_bh);
876 if (!(bs->bh && s->base == bs->bh->b_data))
877 kfree(s->base);
878
879 return error;
880
881 cleanup_dquot:
882 dquot_free_block(inode, 1);
883 goto cleanup;
884
885 bad_block:
886 EXT4_ERROR_INODE(inode, "bad block %llu",
887 EXT4_I(inode)->i_file_acl);
888 goto cleanup;
889
890 #undef header
891 }
892
893 struct ext4_xattr_ibody_find {
894 struct ext4_xattr_search s;
895 struct ext4_iloc iloc;
896 };
897
898 static int
899 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
900 struct ext4_xattr_ibody_find *is)
901 {
902 struct ext4_xattr_ibody_header *header;
903 struct ext4_inode *raw_inode;
904 int error;
905
906 if (EXT4_I(inode)->i_extra_isize == 0)
907 return 0;
908 raw_inode = ext4_raw_inode(&is->iloc);
909 header = IHDR(inode, raw_inode);
910 is->s.base = is->s.first = IFIRST(header);
911 is->s.here = is->s.first;
912 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
913 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
914 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
915 if (error)
916 return error;
917 /* Find the named attribute. */
918 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
919 i->name, is->s.end -
920 (void *)is->s.base, 0);
921 if (error && error != -ENODATA)
922 return error;
923 is->s.not_found = error;
924 }
925 return 0;
926 }
927
928 static int
929 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
930 struct ext4_xattr_info *i,
931 struct ext4_xattr_ibody_find *is)
932 {
933 struct ext4_xattr_ibody_header *header;
934 struct ext4_xattr_search *s = &is->s;
935 int error;
936
937 if (EXT4_I(inode)->i_extra_isize == 0)
938 return -ENOSPC;
939 error = ext4_xattr_set_entry(i, s);
940 if (error)
941 return error;
942 header = IHDR(inode, ext4_raw_inode(&is->iloc));
943 if (!IS_LAST_ENTRY(s->first)) {
944 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
945 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
946 } else {
947 header->h_magic = cpu_to_le32(0);
948 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
949 }
950 return 0;
951 }
952
953 /*
954 * ext4_xattr_set_handle()
955 *
956 * Create, replace or remove an extended attribute for this inode. Value
957 * is NULL to remove an existing extended attribute, and non-NULL to
958 * either replace an existing extended attribute, or create a new extended
959 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
960 * specify that an extended attribute must exist and must not exist
961 * previous to the call, respectively.
962 *
963 * Returns 0, or a negative error number on failure.
964 */
965 int
966 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
967 const char *name, const void *value, size_t value_len,
968 int flags)
969 {
970 struct ext4_xattr_info i = {
971 .name_index = name_index,
972 .name = name,
973 .value = value,
974 .value_len = value_len,
975
976 };
977 struct ext4_xattr_ibody_find is = {
978 .s = { .not_found = -ENODATA, },
979 };
980 struct ext4_xattr_block_find bs = {
981 .s = { .not_found = -ENODATA, },
982 };
983 unsigned long no_expand;
984 int error;
985
986 if (!name)
987 return -EINVAL;
988 if (strlen(name) > 255)
989 return -ERANGE;
990 down_write(&EXT4_I(inode)->xattr_sem);
991 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
992 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
993
994 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
995 if (error)
996 goto cleanup;
997
998 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
999 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1000 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1001 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1002 }
1003
1004 error = ext4_xattr_ibody_find(inode, &i, &is);
1005 if (error)
1006 goto cleanup;
1007 if (is.s.not_found)
1008 error = ext4_xattr_block_find(inode, &i, &bs);
1009 if (error)
1010 goto cleanup;
1011 if (is.s.not_found && bs.s.not_found) {
1012 error = -ENODATA;
1013 if (flags & XATTR_REPLACE)
1014 goto cleanup;
1015 error = 0;
1016 if (!value)
1017 goto cleanup;
1018 } else {
1019 error = -EEXIST;
1020 if (flags & XATTR_CREATE)
1021 goto cleanup;
1022 }
1023 if (!value) {
1024 if (!is.s.not_found)
1025 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1026 else if (!bs.s.not_found)
1027 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1028 } else {
1029 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1030 if (!error && !bs.s.not_found) {
1031 i.value = NULL;
1032 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1033 } else if (error == -ENOSPC) {
1034 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1035 error = ext4_xattr_block_find(inode, &i, &bs);
1036 if (error)
1037 goto cleanup;
1038 }
1039 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1040 if (error)
1041 goto cleanup;
1042 if (!is.s.not_found) {
1043 i.value = NULL;
1044 error = ext4_xattr_ibody_set(handle, inode, &i,
1045 &is);
1046 }
1047 }
1048 }
1049 if (!error) {
1050 ext4_xattr_update_super_block(handle, inode->i_sb);
1051 inode->i_ctime = ext4_current_time(inode);
1052 if (!value)
1053 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1054 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1055 /*
1056 * The bh is consumed by ext4_mark_iloc_dirty, even with
1057 * error != 0.
1058 */
1059 is.iloc.bh = NULL;
1060 if (IS_SYNC(inode))
1061 ext4_handle_sync(handle);
1062 }
1063
1064 cleanup:
1065 brelse(is.iloc.bh);
1066 brelse(bs.bh);
1067 if (no_expand == 0)
1068 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1069 up_write(&EXT4_I(inode)->xattr_sem);
1070 return error;
1071 }
1072
1073 /*
1074 * ext4_xattr_set()
1075 *
1076 * Like ext4_xattr_set_handle, but start from an inode. This extended
1077 * attribute modification is a filesystem transaction by itself.
1078 *
1079 * Returns 0, or a negative error number on failure.
1080 */
1081 int
1082 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1083 const void *value, size_t value_len, int flags)
1084 {
1085 handle_t *handle;
1086 int error, retries = 0;
1087
1088 retry:
1089 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1090 if (IS_ERR(handle)) {
1091 error = PTR_ERR(handle);
1092 } else {
1093 int error2;
1094
1095 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1096 value, value_len, flags);
1097 error2 = ext4_journal_stop(handle);
1098 if (error == -ENOSPC &&
1099 ext4_should_retry_alloc(inode->i_sb, &retries))
1100 goto retry;
1101 if (error == 0)
1102 error = error2;
1103 }
1104
1105 return error;
1106 }
1107
1108 /*
1109 * Shift the EA entries in the inode to create space for the increased
1110 * i_extra_isize.
1111 */
1112 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1113 int value_offs_shift, void *to,
1114 void *from, size_t n, int blocksize)
1115 {
1116 struct ext4_xattr_entry *last = entry;
1117 int new_offs;
1118
1119 /* Adjust the value offsets of the entries */
1120 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1121 if (!last->e_value_block && last->e_value_size) {
1122 new_offs = le16_to_cpu(last->e_value_offs) +
1123 value_offs_shift;
1124 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1125 > blocksize);
1126 last->e_value_offs = cpu_to_le16(new_offs);
1127 }
1128 }
1129 /* Shift the entries by n bytes */
1130 memmove(to, from, n);
1131 }
1132
1133 /*
1134 * Expand an inode by new_extra_isize bytes when EAs are present.
1135 * Returns 0 on success or negative error number on failure.
1136 */
1137 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1138 struct ext4_inode *raw_inode, handle_t *handle)
1139 {
1140 struct ext4_xattr_ibody_header *header;
1141 struct ext4_xattr_entry *entry, *last, *first;
1142 struct buffer_head *bh = NULL;
1143 struct ext4_xattr_ibody_find *is = NULL;
1144 struct ext4_xattr_block_find *bs = NULL;
1145 char *buffer = NULL, *b_entry_name = NULL;
1146 size_t min_offs, free;
1147 int total_ino, total_blk;
1148 void *base, *start, *end;
1149 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1150 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1151
1152 down_write(&EXT4_I(inode)->xattr_sem);
1153 retry:
1154 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1155 up_write(&EXT4_I(inode)->xattr_sem);
1156 return 0;
1157 }
1158
1159 header = IHDR(inode, raw_inode);
1160 entry = IFIRST(header);
1161
1162 /*
1163 * Check if enough free space is available in the inode to shift the
1164 * entries ahead by new_extra_isize.
1165 */
1166
1167 base = start = entry;
1168 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1169 min_offs = end - base;
1170 last = entry;
1171 total_ino = sizeof(struct ext4_xattr_ibody_header);
1172
1173 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1174 if (free >= new_extra_isize) {
1175 entry = IFIRST(header);
1176 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1177 - new_extra_isize, (void *)raw_inode +
1178 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1179 (void *)header, total_ino,
1180 inode->i_sb->s_blocksize);
1181 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1182 error = 0;
1183 goto cleanup;
1184 }
1185
1186 /*
1187 * Enough free space isn't available in the inode, check if
1188 * EA block can hold new_extra_isize bytes.
1189 */
1190 if (EXT4_I(inode)->i_file_acl) {
1191 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1192 error = -EIO;
1193 if (!bh)
1194 goto cleanup;
1195 if (ext4_xattr_check_block(bh)) {
1196 EXT4_ERROR_INODE(inode, "bad block %llu",
1197 EXT4_I(inode)->i_file_acl);
1198 error = -EIO;
1199 goto cleanup;
1200 }
1201 base = BHDR(bh);
1202 first = BFIRST(bh);
1203 end = bh->b_data + bh->b_size;
1204 min_offs = end - base;
1205 free = ext4_xattr_free_space(first, &min_offs, base,
1206 &total_blk);
1207 if (free < new_extra_isize) {
1208 if (!tried_min_extra_isize && s_min_extra_isize) {
1209 tried_min_extra_isize++;
1210 new_extra_isize = s_min_extra_isize;
1211 brelse(bh);
1212 goto retry;
1213 }
1214 error = -1;
1215 goto cleanup;
1216 }
1217 } else {
1218 free = inode->i_sb->s_blocksize;
1219 }
1220
1221 while (new_extra_isize > 0) {
1222 size_t offs, size, entry_size;
1223 struct ext4_xattr_entry *small_entry = NULL;
1224 struct ext4_xattr_info i = {
1225 .value = NULL,
1226 .value_len = 0,
1227 };
1228 unsigned int total_size; /* EA entry size + value size */
1229 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1230 unsigned int min_total_size = ~0U;
1231
1232 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1233 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1234 if (!is || !bs) {
1235 error = -ENOMEM;
1236 goto cleanup;
1237 }
1238
1239 is->s.not_found = -ENODATA;
1240 bs->s.not_found = -ENODATA;
1241 is->iloc.bh = NULL;
1242 bs->bh = NULL;
1243
1244 last = IFIRST(header);
1245 /* Find the entry best suited to be pushed into EA block */
1246 entry = NULL;
1247 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1248 total_size =
1249 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1250 EXT4_XATTR_LEN(last->e_name_len);
1251 if (total_size <= free && total_size < min_total_size) {
1252 if (total_size < new_extra_isize) {
1253 small_entry = last;
1254 } else {
1255 entry = last;
1256 min_total_size = total_size;
1257 }
1258 }
1259 }
1260
1261 if (entry == NULL) {
1262 if (small_entry) {
1263 entry = small_entry;
1264 } else {
1265 if (!tried_min_extra_isize &&
1266 s_min_extra_isize) {
1267 tried_min_extra_isize++;
1268 new_extra_isize = s_min_extra_isize;
1269 goto retry;
1270 }
1271 error = -1;
1272 goto cleanup;
1273 }
1274 }
1275 offs = le16_to_cpu(entry->e_value_offs);
1276 size = le32_to_cpu(entry->e_value_size);
1277 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1278 i.name_index = entry->e_name_index,
1279 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1280 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1281 if (!buffer || !b_entry_name) {
1282 error = -ENOMEM;
1283 goto cleanup;
1284 }
1285 /* Save the entry name and the entry value */
1286 memcpy(buffer, (void *)IFIRST(header) + offs,
1287 EXT4_XATTR_SIZE(size));
1288 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1289 b_entry_name[entry->e_name_len] = '\0';
1290 i.name = b_entry_name;
1291
1292 error = ext4_get_inode_loc(inode, &is->iloc);
1293 if (error)
1294 goto cleanup;
1295
1296 error = ext4_xattr_ibody_find(inode, &i, is);
1297 if (error)
1298 goto cleanup;
1299
1300 /* Remove the chosen entry from the inode */
1301 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1302 if (error)
1303 goto cleanup;
1304
1305 entry = IFIRST(header);
1306 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1307 shift_bytes = new_extra_isize;
1308 else
1309 shift_bytes = entry_size + size;
1310 /* Adjust the offsets and shift the remaining entries ahead */
1311 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1312 shift_bytes, (void *)raw_inode +
1313 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1314 (void *)header, total_ino - entry_size,
1315 inode->i_sb->s_blocksize);
1316
1317 extra_isize += shift_bytes;
1318 new_extra_isize -= shift_bytes;
1319 EXT4_I(inode)->i_extra_isize = extra_isize;
1320
1321 i.name = b_entry_name;
1322 i.value = buffer;
1323 i.value_len = size;
1324 error = ext4_xattr_block_find(inode, &i, bs);
1325 if (error)
1326 goto cleanup;
1327
1328 /* Add entry which was removed from the inode into the block */
1329 error = ext4_xattr_block_set(handle, inode, &i, bs);
1330 if (error)
1331 goto cleanup;
1332 kfree(b_entry_name);
1333 kfree(buffer);
1334 b_entry_name = NULL;
1335 buffer = NULL;
1336 brelse(is->iloc.bh);
1337 kfree(is);
1338 kfree(bs);
1339 }
1340 brelse(bh);
1341 up_write(&EXT4_I(inode)->xattr_sem);
1342 return 0;
1343
1344 cleanup:
1345 kfree(b_entry_name);
1346 kfree(buffer);
1347 if (is)
1348 brelse(is->iloc.bh);
1349 kfree(is);
1350 kfree(bs);
1351 brelse(bh);
1352 up_write(&EXT4_I(inode)->xattr_sem);
1353 return error;
1354 }
1355
1356
1357
1358 /*
1359 * ext4_xattr_delete_inode()
1360 *
1361 * Free extended attribute resources associated with this inode. This
1362 * is called immediately before an inode is freed. We have exclusive
1363 * access to the inode.
1364 */
1365 void
1366 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1367 {
1368 struct buffer_head *bh = NULL;
1369
1370 if (!EXT4_I(inode)->i_file_acl)
1371 goto cleanup;
1372 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1373 if (!bh) {
1374 EXT4_ERROR_INODE(inode, "block %llu read error",
1375 EXT4_I(inode)->i_file_acl);
1376 goto cleanup;
1377 }
1378 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1379 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1380 EXT4_ERROR_INODE(inode, "bad block %llu",
1381 EXT4_I(inode)->i_file_acl);
1382 goto cleanup;
1383 }
1384 ext4_xattr_release_block(handle, inode, bh);
1385 EXT4_I(inode)->i_file_acl = 0;
1386
1387 cleanup:
1388 brelse(bh);
1389 }
1390
1391 /*
1392 * ext4_xattr_put_super()
1393 *
1394 * This is called when a file system is unmounted.
1395 */
1396 void
1397 ext4_xattr_put_super(struct super_block *sb)
1398 {
1399 mb_cache_shrink(sb->s_bdev);
1400 }
1401
1402 /*
1403 * ext4_xattr_cache_insert()
1404 *
1405 * Create a new entry in the extended attribute cache, and insert
1406 * it unless such an entry is already in the cache.
1407 *
1408 * Returns 0, or a negative error number on failure.
1409 */
1410 static void
1411 ext4_xattr_cache_insert(struct buffer_head *bh)
1412 {
1413 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1414 struct mb_cache_entry *ce;
1415 int error;
1416
1417 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1418 if (!ce) {
1419 ea_bdebug(bh, "out of memory");
1420 return;
1421 }
1422 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1423 if (error) {
1424 mb_cache_entry_free(ce);
1425 if (error == -EBUSY) {
1426 ea_bdebug(bh, "already in cache");
1427 error = 0;
1428 }
1429 } else {
1430 ea_bdebug(bh, "inserting [%x]", (int)hash);
1431 mb_cache_entry_release(ce);
1432 }
1433 }
1434
1435 /*
1436 * ext4_xattr_cmp()
1437 *
1438 * Compare two extended attribute blocks for equality.
1439 *
1440 * Returns 0 if the blocks are equal, 1 if they differ, and
1441 * a negative error number on errors.
1442 */
1443 static int
1444 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1445 struct ext4_xattr_header *header2)
1446 {
1447 struct ext4_xattr_entry *entry1, *entry2;
1448
1449 entry1 = ENTRY(header1+1);
1450 entry2 = ENTRY(header2+1);
1451 while (!IS_LAST_ENTRY(entry1)) {
1452 if (IS_LAST_ENTRY(entry2))
1453 return 1;
1454 if (entry1->e_hash != entry2->e_hash ||
1455 entry1->e_name_index != entry2->e_name_index ||
1456 entry1->e_name_len != entry2->e_name_len ||
1457 entry1->e_value_size != entry2->e_value_size ||
1458 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1459 return 1;
1460 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1461 return -EIO;
1462 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1463 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1464 le32_to_cpu(entry1->e_value_size)))
1465 return 1;
1466
1467 entry1 = EXT4_XATTR_NEXT(entry1);
1468 entry2 = EXT4_XATTR_NEXT(entry2);
1469 }
1470 if (!IS_LAST_ENTRY(entry2))
1471 return 1;
1472 return 0;
1473 }
1474
1475 /*
1476 * ext4_xattr_cache_find()
1477 *
1478 * Find an identical extended attribute block.
1479 *
1480 * Returns a pointer to the block found, or NULL if such a block was
1481 * not found or an error occurred.
1482 */
1483 static struct buffer_head *
1484 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1485 struct mb_cache_entry **pce)
1486 {
1487 __u32 hash = le32_to_cpu(header->h_hash);
1488 struct mb_cache_entry *ce;
1489
1490 if (!header->h_hash)
1491 return NULL; /* never share */
1492 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1493 again:
1494 ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1495 hash);
1496 while (ce) {
1497 struct buffer_head *bh;
1498
1499 if (IS_ERR(ce)) {
1500 if (PTR_ERR(ce) == -EAGAIN)
1501 goto again;
1502 break;
1503 }
1504 bh = sb_bread(inode->i_sb, ce->e_block);
1505 if (!bh) {
1506 EXT4_ERROR_INODE(inode, "block %lu read error",
1507 (unsigned long) ce->e_block);
1508 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1509 EXT4_XATTR_REFCOUNT_MAX) {
1510 ea_idebug(inode, "block %lu refcount %d>=%d",
1511 (unsigned long) ce->e_block,
1512 le32_to_cpu(BHDR(bh)->h_refcount),
1513 EXT4_XATTR_REFCOUNT_MAX);
1514 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1515 *pce = ce;
1516 return bh;
1517 }
1518 brelse(bh);
1519 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1520 }
1521 return NULL;
1522 }
1523
1524 #define NAME_HASH_SHIFT 5
1525 #define VALUE_HASH_SHIFT 16
1526
1527 /*
1528 * ext4_xattr_hash_entry()
1529 *
1530 * Compute the hash of an extended attribute.
1531 */
1532 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1533 struct ext4_xattr_entry *entry)
1534 {
1535 __u32 hash = 0;
1536 char *name = entry->e_name;
1537 int n;
1538
1539 for (n = 0; n < entry->e_name_len; n++) {
1540 hash = (hash << NAME_HASH_SHIFT) ^
1541 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1542 *name++;
1543 }
1544
1545 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1546 __le32 *value = (__le32 *)((char *)header +
1547 le16_to_cpu(entry->e_value_offs));
1548 for (n = (le32_to_cpu(entry->e_value_size) +
1549 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1550 hash = (hash << VALUE_HASH_SHIFT) ^
1551 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1552 le32_to_cpu(*value++);
1553 }
1554 }
1555 entry->e_hash = cpu_to_le32(hash);
1556 }
1557
1558 #undef NAME_HASH_SHIFT
1559 #undef VALUE_HASH_SHIFT
1560
1561 #define BLOCK_HASH_SHIFT 16
1562
1563 /*
1564 * ext4_xattr_rehash()
1565 *
1566 * Re-compute the extended attribute hash value after an entry has changed.
1567 */
1568 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1569 struct ext4_xattr_entry *entry)
1570 {
1571 struct ext4_xattr_entry *here;
1572 __u32 hash = 0;
1573
1574 ext4_xattr_hash_entry(header, entry);
1575 here = ENTRY(header+1);
1576 while (!IS_LAST_ENTRY(here)) {
1577 if (!here->e_hash) {
1578 /* Block is not shared if an entry's hash value == 0 */
1579 hash = 0;
1580 break;
1581 }
1582 hash = (hash << BLOCK_HASH_SHIFT) ^
1583 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1584 le32_to_cpu(here->e_hash);
1585 here = EXT4_XATTR_NEXT(here);
1586 }
1587 header->h_hash = cpu_to_le32(hash);
1588 }
1589
1590 #undef BLOCK_HASH_SHIFT
1591
1592 int __init
1593 ext4_init_xattr(void)
1594 {
1595 ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1596 if (!ext4_xattr_cache)
1597 return -ENOMEM;
1598 return 0;
1599 }
1600
1601 void
1602 ext4_exit_xattr(void)
1603 {
1604 if (ext4_xattr_cache)
1605 mb_cache_destroy(ext4_xattr_cache);
1606 ext4_xattr_cache = NULL;
1607 }
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