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proc: Add proc_mkdir_data()
[linux-2.6.git] / fs / ext4 / xattr.c
blob3a120b277240e70b44fede9fa0b9ffa98b85118b
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 #ifdef EXT4_XATTR_DEBUG
65 # define ea_idebug(inode, f...) do { \
66 printk(KERN_DEBUG "inode %s:%lu: ", \
67 inode->i_sb->s_id, inode->i_ino); \
68 printk(f); \
69 printk("\n"); \
70 } while (0)
71 # define ea_bdebug(bh, f...) do { \
72 char b[BDEVNAME_SIZE]; \
73 printk(KERN_DEBUG "block %s:%lu: ", \
74 bdevname(bh->b_bdev, b), \
75 (unsigned long) bh->b_blocknr); \
76 printk(f); \
77 printk("\n"); \
78 } while (0)
79 #else
80 # define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
81 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
82 #endif
83
84 static void ext4_xattr_cache_insert(struct buffer_head *);
85 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
86 struct ext4_xattr_header *,
87 struct mb_cache_entry **);
88 static void ext4_xattr_rehash(struct ext4_xattr_header *,
89 struct ext4_xattr_entry *);
90 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
91 size_t buffer_size);
92
93 static struct mb_cache *ext4_xattr_cache;
94
95 static const struct xattr_handler *ext4_xattr_handler_map[] = {
96 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
97 #ifdef CONFIG_EXT4_FS_POSIX_ACL
98 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
99 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
100 #endif
101 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
102 #ifdef CONFIG_EXT4_FS_SECURITY
103 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
104 #endif
105 };
106
107 const struct xattr_handler *ext4_xattr_handlers[] = {
108 &ext4_xattr_user_handler,
109 &ext4_xattr_trusted_handler,
110 #ifdef CONFIG_EXT4_FS_POSIX_ACL
111 &ext4_xattr_acl_access_handler,
112 &ext4_xattr_acl_default_handler,
113 #endif
114 #ifdef CONFIG_EXT4_FS_SECURITY
115 &ext4_xattr_security_handler,
116 #endif
117 NULL
118 };
119
120 static __le32 ext4_xattr_block_csum(struct inode *inode,
121 sector_t block_nr,
122 struct ext4_xattr_header *hdr)
123 {
124 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
125 __u32 csum, old;
126
127 old = hdr->h_checksum;
128 hdr->h_checksum = 0;
129 block_nr = cpu_to_le64(block_nr);
130 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&block_nr,
131 sizeof(block_nr));
132 csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
133 EXT4_BLOCK_SIZE(inode->i_sb));
134
135 hdr->h_checksum = old;
136 return cpu_to_le32(csum);
137 }
138
139 static int ext4_xattr_block_csum_verify(struct inode *inode,
140 sector_t block_nr,
141 struct ext4_xattr_header *hdr)
142 {
143 if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
144 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
145 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
146 return 0;
147 return 1;
148 }
149
150 static void ext4_xattr_block_csum_set(struct inode *inode,
151 sector_t block_nr,
152 struct ext4_xattr_header *hdr)
153 {
154 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
155 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
156 return;
157
158 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
159 }
160
161 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
162 struct inode *inode,
163 struct buffer_head *bh)
164 {
165 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
166 return ext4_handle_dirty_metadata(handle, inode, bh);
167 }
168
169 static inline const struct xattr_handler *
170 ext4_xattr_handler(int name_index)
171 {
172 const struct xattr_handler *handler = NULL;
173
174 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
175 handler = ext4_xattr_handler_map[name_index];
176 return handler;
177 }
178
179 /*
180 * Inode operation listxattr()
181 *
182 * dentry->d_inode->i_mutex: don't care
183 */
184 ssize_t
185 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
186 {
187 return ext4_xattr_list(dentry, buffer, size);
188 }
189
190 static int
191 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
192 {
193 while (!IS_LAST_ENTRY(entry)) {
194 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
195 if ((void *)next >= end)
196 return -EIO;
197 entry = next;
198 }
199 return 0;
200 }
201
202 static inline int
203 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
204 {
205 int error;
206
207 if (buffer_verified(bh))
208 return 0;
209
210 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
211 BHDR(bh)->h_blocks != cpu_to_le32(1))
212 return -EIO;
213 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
214 return -EIO;
215 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
216 if (!error)
217 set_buffer_verified(bh);
218 return error;
219 }
220
221 static inline int
222 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
223 {
224 size_t value_size = le32_to_cpu(entry->e_value_size);
225
226 if (entry->e_value_block != 0 || value_size > size ||
227 le16_to_cpu(entry->e_value_offs) + value_size > size)
228 return -EIO;
229 return 0;
230 }
231
232 static int
233 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
234 const char *name, size_t size, int sorted)
235 {
236 struct ext4_xattr_entry *entry;
237 size_t name_len;
238 int cmp = 1;
239
240 if (name == NULL)
241 return -EINVAL;
242 name_len = strlen(name);
243 entry = *pentry;
244 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
245 cmp = name_index - entry->e_name_index;
246 if (!cmp)
247 cmp = name_len - entry->e_name_len;
248 if (!cmp)
249 cmp = memcmp(name, entry->e_name, name_len);
250 if (cmp <= 0 && (sorted || cmp == 0))
251 break;
252 }
253 *pentry = entry;
254 if (!cmp && ext4_xattr_check_entry(entry, size))
255 return -EIO;
256 return cmp ? -ENODATA : 0;
257 }
258
259 static int
260 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
261 void *buffer, size_t buffer_size)
262 {
263 struct buffer_head *bh = NULL;
264 struct ext4_xattr_entry *entry;
265 size_t size;
266 int error;
267
268 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
269 name_index, name, buffer, (long)buffer_size);
270
271 error = -ENODATA;
272 if (!EXT4_I(inode)->i_file_acl)
273 goto cleanup;
274 ea_idebug(inode, "reading block %llu",
275 (unsigned long long)EXT4_I(inode)->i_file_acl);
276 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
277 if (!bh)
278 goto cleanup;
279 ea_bdebug(bh, "b_count=%d, refcount=%d",
280 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
281 if (ext4_xattr_check_block(inode, bh)) {
282 bad_block:
283 EXT4_ERROR_INODE(inode, "bad block %llu",
284 EXT4_I(inode)->i_file_acl);
285 error = -EIO;
286 goto cleanup;
287 }
288 ext4_xattr_cache_insert(bh);
289 entry = BFIRST(bh);
290 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
291 if (error == -EIO)
292 goto bad_block;
293 if (error)
294 goto cleanup;
295 size = le32_to_cpu(entry->e_value_size);
296 if (buffer) {
297 error = -ERANGE;
298 if (size > buffer_size)
299 goto cleanup;
300 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
301 size);
302 }
303 error = size;
304
305 cleanup:
306 brelse(bh);
307 return error;
308 }
309
310 int
311 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
312 void *buffer, size_t buffer_size)
313 {
314 struct ext4_xattr_ibody_header *header;
315 struct ext4_xattr_entry *entry;
316 struct ext4_inode *raw_inode;
317 struct ext4_iloc iloc;
318 size_t size;
319 void *end;
320 int error;
321
322 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
323 return -ENODATA;
324 error = ext4_get_inode_loc(inode, &iloc);
325 if (error)
326 return error;
327 raw_inode = ext4_raw_inode(&iloc);
328 header = IHDR(inode, raw_inode);
329 entry = IFIRST(header);
330 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
331 error = ext4_xattr_check_names(entry, end);
332 if (error)
333 goto cleanup;
334 error = ext4_xattr_find_entry(&entry, name_index, name,
335 end - (void *)entry, 0);
336 if (error)
337 goto cleanup;
338 size = le32_to_cpu(entry->e_value_size);
339 if (buffer) {
340 error = -ERANGE;
341 if (size > buffer_size)
342 goto cleanup;
343 memcpy(buffer, (void *)IFIRST(header) +
344 le16_to_cpu(entry->e_value_offs), size);
345 }
346 error = size;
347
348 cleanup:
349 brelse(iloc.bh);
350 return error;
351 }
352
353 /*
354 * ext4_xattr_get()
355 *
356 * Copy an extended attribute into the buffer
357 * provided, or compute the buffer size required.
358 * Buffer is NULL to compute the size of the buffer required.
359 *
360 * Returns a negative error number on failure, or the number of bytes
361 * used / required on success.
362 */
363 int
364 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
365 void *buffer, size_t buffer_size)
366 {
367 int error;
368
369 down_read(&EXT4_I(inode)->xattr_sem);
370 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
371 buffer_size);
372 if (error == -ENODATA)
373 error = ext4_xattr_block_get(inode, name_index, name, buffer,
374 buffer_size);
375 up_read(&EXT4_I(inode)->xattr_sem);
376 return error;
377 }
378
379 static int
380 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
381 char *buffer, size_t buffer_size)
382 {
383 size_t rest = buffer_size;
384
385 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
386 const struct xattr_handler *handler =
387 ext4_xattr_handler(entry->e_name_index);
388
389 if (handler) {
390 size_t size = handler->list(dentry, buffer, rest,
391 entry->e_name,
392 entry->e_name_len,
393 handler->flags);
394 if (buffer) {
395 if (size > rest)
396 return -ERANGE;
397 buffer += size;
398 }
399 rest -= size;
400 }
401 }
402 return buffer_size - rest;
403 }
404
405 static int
406 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
407 {
408 struct inode *inode = dentry->d_inode;
409 struct buffer_head *bh = NULL;
410 int error;
411
412 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
413 buffer, (long)buffer_size);
414
415 error = 0;
416 if (!EXT4_I(inode)->i_file_acl)
417 goto cleanup;
418 ea_idebug(inode, "reading block %llu",
419 (unsigned long long)EXT4_I(inode)->i_file_acl);
420 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
421 error = -EIO;
422 if (!bh)
423 goto cleanup;
424 ea_bdebug(bh, "b_count=%d, refcount=%d",
425 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
426 if (ext4_xattr_check_block(inode, bh)) {
427 EXT4_ERROR_INODE(inode, "bad block %llu",
428 EXT4_I(inode)->i_file_acl);
429 error = -EIO;
430 goto cleanup;
431 }
432 ext4_xattr_cache_insert(bh);
433 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
434
435 cleanup:
436 brelse(bh);
437
438 return error;
439 }
440
441 static int
442 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
443 {
444 struct inode *inode = dentry->d_inode;
445 struct ext4_xattr_ibody_header *header;
446 struct ext4_inode *raw_inode;
447 struct ext4_iloc iloc;
448 void *end;
449 int error;
450
451 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
452 return 0;
453 error = ext4_get_inode_loc(inode, &iloc);
454 if (error)
455 return error;
456 raw_inode = ext4_raw_inode(&iloc);
457 header = IHDR(inode, raw_inode);
458 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
459 error = ext4_xattr_check_names(IFIRST(header), end);
460 if (error)
461 goto cleanup;
462 error = ext4_xattr_list_entries(dentry, IFIRST(header),
463 buffer, buffer_size);
464
465 cleanup:
466 brelse(iloc.bh);
467 return error;
468 }
469
470 /*
471 * ext4_xattr_list()
472 *
473 * Copy a list of attribute names into the buffer
474 * provided, or compute the buffer size required.
475 * Buffer is NULL to compute the size of the buffer required.
476 *
477 * Returns a negative error number on failure, or the number of bytes
478 * used / required on success.
479 */
480 static int
481 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
482 {
483 int ret, ret2;
484
485 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
486 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
487 if (ret < 0)
488 goto errout;
489 if (buffer) {
490 buffer += ret;
491 buffer_size -= ret;
492 }
493 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
494 if (ret < 0)
495 goto errout;
496 ret += ret2;
497 errout:
498 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
499 return ret;
500 }
501
502 /*
503 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
504 * not set, set it.
505 */
506 static void ext4_xattr_update_super_block(handle_t *handle,
507 struct super_block *sb)
508 {
509 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
510 return;
511
512 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
513 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
514 ext4_handle_dirty_super(handle, sb);
515 }
516 }
517
518 /*
519 * Release the xattr block BH: If the reference count is > 1, decrement
520 * it; otherwise free the block.
521 */
522 static void
523 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
524 struct buffer_head *bh)
525 {
526 struct mb_cache_entry *ce = NULL;
527 int error = 0;
528
529 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
530 error = ext4_journal_get_write_access(handle, bh);
531 if (error)
532 goto out;
533
534 lock_buffer(bh);
535 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
536 ea_bdebug(bh, "refcount now=0; freeing");
537 if (ce)
538 mb_cache_entry_free(ce);
539 get_bh(bh);
540 ext4_free_blocks(handle, inode, bh, 0, 1,
541 EXT4_FREE_BLOCKS_METADATA |
542 EXT4_FREE_BLOCKS_FORGET);
543 unlock_buffer(bh);
544 } else {
545 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
546 if (ce)
547 mb_cache_entry_release(ce);
548 unlock_buffer(bh);
549 error = ext4_handle_dirty_xattr_block(handle, inode, bh);
550 if (IS_SYNC(inode))
551 ext4_handle_sync(handle);
552 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
553 ea_bdebug(bh, "refcount now=%d; releasing",
554 le32_to_cpu(BHDR(bh)->h_refcount));
555 }
556 out:
557 ext4_std_error(inode->i_sb, error);
558 return;
559 }
560
561 /*
562 * Find the available free space for EAs. This also returns the total number of
563 * bytes used by EA entries.
564 */
565 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
566 size_t *min_offs, void *base, int *total)
567 {
568 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
569 *total += EXT4_XATTR_LEN(last->e_name_len);
570 if (!last->e_value_block && last->e_value_size) {
571 size_t offs = le16_to_cpu(last->e_value_offs);
572 if (offs < *min_offs)
573 *min_offs = offs;
574 }
575 }
576 return (*min_offs - ((void *)last - base) - sizeof(__u32));
577 }
578
579 static int
580 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
581 {
582 struct ext4_xattr_entry *last;
583 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
584
585 /* Compute min_offs and last. */
586 last = s->first;
587 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
588 if (!last->e_value_block && last->e_value_size) {
589 size_t offs = le16_to_cpu(last->e_value_offs);
590 if (offs < min_offs)
591 min_offs = offs;
592 }
593 }
594 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
595 if (!s->not_found) {
596 if (!s->here->e_value_block && s->here->e_value_size) {
597 size_t size = le32_to_cpu(s->here->e_value_size);
598 free += EXT4_XATTR_SIZE(size);
599 }
600 free += EXT4_XATTR_LEN(name_len);
601 }
602 if (i->value) {
603 if (free < EXT4_XATTR_SIZE(i->value_len) ||
604 free < EXT4_XATTR_LEN(name_len) +
605 EXT4_XATTR_SIZE(i->value_len))
606 return -ENOSPC;
607 }
608
609 if (i->value && s->not_found) {
610 /* Insert the new name. */
611 size_t size = EXT4_XATTR_LEN(name_len);
612 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
613 memmove((void *)s->here + size, s->here, rest);
614 memset(s->here, 0, size);
615 s->here->e_name_index = i->name_index;
616 s->here->e_name_len = name_len;
617 memcpy(s->here->e_name, i->name, name_len);
618 } else {
619 if (!s->here->e_value_block && s->here->e_value_size) {
620 void *first_val = s->base + min_offs;
621 size_t offs = le16_to_cpu(s->here->e_value_offs);
622 void *val = s->base + offs;
623 size_t size = EXT4_XATTR_SIZE(
624 le32_to_cpu(s->here->e_value_size));
625
626 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
627 /* The old and the new value have the same
628 size. Just replace. */
629 s->here->e_value_size =
630 cpu_to_le32(i->value_len);
631 if (i->value == EXT4_ZERO_XATTR_VALUE) {
632 memset(val, 0, size);
633 } else {
634 /* Clear pad bytes first. */
635 memset(val + size - EXT4_XATTR_PAD, 0,
636 EXT4_XATTR_PAD);
637 memcpy(val, i->value, i->value_len);
638 }
639 return 0;
640 }
641
642 /* Remove the old value. */
643 memmove(first_val + size, first_val, val - first_val);
644 memset(first_val, 0, size);
645 s->here->e_value_size = 0;
646 s->here->e_value_offs = 0;
647 min_offs += size;
648
649 /* Adjust all value offsets. */
650 last = s->first;
651 while (!IS_LAST_ENTRY(last)) {
652 size_t o = le16_to_cpu(last->e_value_offs);
653 if (!last->e_value_block &&
654 last->e_value_size && o < offs)
655 last->e_value_offs =
656 cpu_to_le16(o + size);
657 last = EXT4_XATTR_NEXT(last);
658 }
659 }
660 if (!i->value) {
661 /* Remove the old name. */
662 size_t size = EXT4_XATTR_LEN(name_len);
663 last = ENTRY((void *)last - size);
664 memmove(s->here, (void *)s->here + size,
665 (void *)last - (void *)s->here + sizeof(__u32));
666 memset(last, 0, size);
667 }
668 }
669
670 if (i->value) {
671 /* Insert the new value. */
672 s->here->e_value_size = cpu_to_le32(i->value_len);
673 if (i->value_len) {
674 size_t size = EXT4_XATTR_SIZE(i->value_len);
675 void *val = s->base + min_offs - size;
676 s->here->e_value_offs = cpu_to_le16(min_offs - size);
677 if (i->value == EXT4_ZERO_XATTR_VALUE) {
678 memset(val, 0, size);
679 } else {
680 /* Clear the pad bytes first. */
681 memset(val + size - EXT4_XATTR_PAD, 0,
682 EXT4_XATTR_PAD);
683 memcpy(val, i->value, i->value_len);
684 }
685 }
686 }
687 return 0;
688 }
689
690 struct ext4_xattr_block_find {
691 struct ext4_xattr_search s;
692 struct buffer_head *bh;
693 };
694
695 static int
696 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
697 struct ext4_xattr_block_find *bs)
698 {
699 struct super_block *sb = inode->i_sb;
700 int error;
701
702 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
703 i->name_index, i->name, i->value, (long)i->value_len);
704
705 if (EXT4_I(inode)->i_file_acl) {
706 /* The inode already has an extended attribute block. */
707 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
708 error = -EIO;
709 if (!bs->bh)
710 goto cleanup;
711 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
712 atomic_read(&(bs->bh->b_count)),
713 le32_to_cpu(BHDR(bs->bh)->h_refcount));
714 if (ext4_xattr_check_block(inode, bs->bh)) {
715 EXT4_ERROR_INODE(inode, "bad block %llu",
716 EXT4_I(inode)->i_file_acl);
717 error = -EIO;
718 goto cleanup;
719 }
720 /* Find the named attribute. */
721 bs->s.base = BHDR(bs->bh);
722 bs->s.first = BFIRST(bs->bh);
723 bs->s.end = bs->bh->b_data + bs->bh->b_size;
724 bs->s.here = bs->s.first;
725 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
726 i->name, bs->bh->b_size, 1);
727 if (error && error != -ENODATA)
728 goto cleanup;
729 bs->s.not_found = error;
730 }
731 error = 0;
732
733 cleanup:
734 return error;
735 }
736
737 static int
738 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
739 struct ext4_xattr_info *i,
740 struct ext4_xattr_block_find *bs)
741 {
742 struct super_block *sb = inode->i_sb;
743 struct buffer_head *new_bh = NULL;
744 struct ext4_xattr_search *s = &bs->s;
745 struct mb_cache_entry *ce = NULL;
746 int error = 0;
747
748 #define header(x) ((struct ext4_xattr_header *)(x))
749
750 if (i->value && i->value_len > sb->s_blocksize)
751 return -ENOSPC;
752 if (s->base) {
753 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
754 bs->bh->b_blocknr);
755 error = ext4_journal_get_write_access(handle, bs->bh);
756 if (error)
757 goto cleanup;
758 lock_buffer(bs->bh);
759
760 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
761 if (ce) {
762 mb_cache_entry_free(ce);
763 ce = NULL;
764 }
765 ea_bdebug(bs->bh, "modifying in-place");
766 error = ext4_xattr_set_entry(i, s);
767 if (!error) {
768 if (!IS_LAST_ENTRY(s->first))
769 ext4_xattr_rehash(header(s->base),
770 s->here);
771 ext4_xattr_cache_insert(bs->bh);
772 }
773 unlock_buffer(bs->bh);
774 if (error == -EIO)
775 goto bad_block;
776 if (!error)
777 error = ext4_handle_dirty_xattr_block(handle,
778 inode,
779 bs->bh);
780 if (error)
781 goto cleanup;
782 goto inserted;
783 } else {
784 int offset = (char *)s->here - bs->bh->b_data;
785
786 unlock_buffer(bs->bh);
787 if (ce) {
788 mb_cache_entry_release(ce);
789 ce = NULL;
790 }
791 ea_bdebug(bs->bh, "cloning");
792 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
793 error = -ENOMEM;
794 if (s->base == NULL)
795 goto cleanup;
796 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
797 s->first = ENTRY(header(s->base)+1);
798 header(s->base)->h_refcount = cpu_to_le32(1);
799 s->here = ENTRY(s->base + offset);
800 s->end = s->base + bs->bh->b_size;
801 }
802 } else {
803 /* Allocate a buffer where we construct the new block. */
804 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
805 /* assert(header == s->base) */
806 error = -ENOMEM;
807 if (s->base == NULL)
808 goto cleanup;
809 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
810 header(s->base)->h_blocks = cpu_to_le32(1);
811 header(s->base)->h_refcount = cpu_to_le32(1);
812 s->first = ENTRY(header(s->base)+1);
813 s->here = ENTRY(header(s->base)+1);
814 s->end = s->base + sb->s_blocksize;
815 }
816
817 error = ext4_xattr_set_entry(i, s);
818 if (error == -EIO)
819 goto bad_block;
820 if (error)
821 goto cleanup;
822 if (!IS_LAST_ENTRY(s->first))
823 ext4_xattr_rehash(header(s->base), s->here);
824
825 inserted:
826 if (!IS_LAST_ENTRY(s->first)) {
827 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
828 if (new_bh) {
829 /* We found an identical block in the cache. */
830 if (new_bh == bs->bh)
831 ea_bdebug(new_bh, "keeping");
832 else {
833 /* The old block is released after updating
834 the inode. */
835 error = dquot_alloc_block(inode,
836 EXT4_C2B(EXT4_SB(sb), 1));
837 if (error)
838 goto cleanup;
839 error = ext4_journal_get_write_access(handle,
840 new_bh);
841 if (error)
842 goto cleanup_dquot;
843 lock_buffer(new_bh);
844 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
845 ea_bdebug(new_bh, "reusing; refcount now=%d",
846 le32_to_cpu(BHDR(new_bh)->h_refcount));
847 unlock_buffer(new_bh);
848 error = ext4_handle_dirty_xattr_block(handle,
849 inode,
850 new_bh);
851 if (error)
852 goto cleanup_dquot;
853 }
854 mb_cache_entry_release(ce);
855 ce = NULL;
856 } else if (bs->bh && s->base == bs->bh->b_data) {
857 /* We were modifying this block in-place. */
858 ea_bdebug(bs->bh, "keeping this block");
859 new_bh = bs->bh;
860 get_bh(new_bh);
861 } else {
862 /* We need to allocate a new block */
863 ext4_fsblk_t goal, block;
864
865 goal = ext4_group_first_block_no(sb,
866 EXT4_I(inode)->i_block_group);
867
868 /* non-extent files can't have physical blocks past 2^32 */
869 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
870 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
871
872 /*
873 * take i_data_sem because we will test
874 * i_delalloc_reserved_flag in ext4_mb_new_blocks
875 */
876 down_read((&EXT4_I(inode)->i_data_sem));
877 block = ext4_new_meta_blocks(handle, inode, goal, 0,
878 NULL, &error);
879 up_read((&EXT4_I(inode)->i_data_sem));
880 if (error)
881 goto cleanup;
882
883 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
884 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
885
886 ea_idebug(inode, "creating block %llu",
887 (unsigned long long)block);
888
889 new_bh = sb_getblk(sb, block);
890 if (unlikely(!new_bh)) {
891 error = -ENOMEM;
892 getblk_failed:
893 ext4_free_blocks(handle, inode, NULL, block, 1,
894 EXT4_FREE_BLOCKS_METADATA);
895 goto cleanup;
896 }
897 lock_buffer(new_bh);
898 error = ext4_journal_get_create_access(handle, new_bh);
899 if (error) {
900 unlock_buffer(new_bh);
901 error = -EIO;
902 goto getblk_failed;
903 }
904 memcpy(new_bh->b_data, s->base, new_bh->b_size);
905 set_buffer_uptodate(new_bh);
906 unlock_buffer(new_bh);
907 ext4_xattr_cache_insert(new_bh);
908 error = ext4_handle_dirty_xattr_block(handle,
909 inode, new_bh);
910 if (error)
911 goto cleanup;
912 }
913 }
914
915 /* Update the inode. */
916 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
917
918 /* Drop the previous xattr block. */
919 if (bs->bh && bs->bh != new_bh)
920 ext4_xattr_release_block(handle, inode, bs->bh);
921 error = 0;
922
923 cleanup:
924 if (ce)
925 mb_cache_entry_release(ce);
926 brelse(new_bh);
927 if (!(bs->bh && s->base == bs->bh->b_data))
928 kfree(s->base);
929
930 return error;
931
932 cleanup_dquot:
933 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
934 goto cleanup;
935
936 bad_block:
937 EXT4_ERROR_INODE(inode, "bad block %llu",
938 EXT4_I(inode)->i_file_acl);
939 goto cleanup;
940
941 #undef header
942 }
943
944 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
945 struct ext4_xattr_ibody_find *is)
946 {
947 struct ext4_xattr_ibody_header *header;
948 struct ext4_inode *raw_inode;
949 int error;
950
951 if (EXT4_I(inode)->i_extra_isize == 0)
952 return 0;
953 raw_inode = ext4_raw_inode(&is->iloc);
954 header = IHDR(inode, raw_inode);
955 is->s.base = is->s.first = IFIRST(header);
956 is->s.here = is->s.first;
957 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
958 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
959 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
960 if (error)
961 return error;
962 /* Find the named attribute. */
963 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
964 i->name, is->s.end -
965 (void *)is->s.base, 0);
966 if (error && error != -ENODATA)
967 return error;
968 is->s.not_found = error;
969 }
970 return 0;
971 }
972
973 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
974 struct ext4_xattr_info *i,
975 struct ext4_xattr_ibody_find *is)
976 {
977 struct ext4_xattr_ibody_header *header;
978 struct ext4_xattr_search *s = &is->s;
979 int error;
980
981 if (EXT4_I(inode)->i_extra_isize == 0)
982 return -ENOSPC;
983 error = ext4_xattr_set_entry(i, s);
984 if (error) {
985 if (error == -ENOSPC &&
986 ext4_has_inline_data(inode)) {
987 error = ext4_try_to_evict_inline_data(handle, inode,
988 EXT4_XATTR_LEN(strlen(i->name) +
989 EXT4_XATTR_SIZE(i->value_len)));
990 if (error)
991 return error;
992 error = ext4_xattr_ibody_find(inode, i, is);
993 if (error)
994 return error;
995 error = ext4_xattr_set_entry(i, s);
996 }
997 if (error)
998 return error;
999 }
1000 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1001 if (!IS_LAST_ENTRY(s->first)) {
1002 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1003 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1004 } else {
1005 header->h_magic = cpu_to_le32(0);
1006 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1007 }
1008 return 0;
1009 }
1010
1011 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1012 struct ext4_xattr_info *i,
1013 struct ext4_xattr_ibody_find *is)
1014 {
1015 struct ext4_xattr_ibody_header *header;
1016 struct ext4_xattr_search *s = &is->s;
1017 int error;
1018
1019 if (EXT4_I(inode)->i_extra_isize == 0)
1020 return -ENOSPC;
1021 error = ext4_xattr_set_entry(i, s);
1022 if (error)
1023 return error;
1024 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1025 if (!IS_LAST_ENTRY(s->first)) {
1026 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1027 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1028 } else {
1029 header->h_magic = cpu_to_le32(0);
1030 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1031 }
1032 return 0;
1033 }
1034
1035 /*
1036 * ext4_xattr_set_handle()
1037 *
1038 * Create, replace or remove an extended attribute for this inode. Value
1039 * is NULL to remove an existing extended attribute, and non-NULL to
1040 * either replace an existing extended attribute, or create a new extended
1041 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1042 * specify that an extended attribute must exist and must not exist
1043 * previous to the call, respectively.
1044 *
1045 * Returns 0, or a negative error number on failure.
1046 */
1047 int
1048 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1049 const char *name, const void *value, size_t value_len,
1050 int flags)
1051 {
1052 struct ext4_xattr_info i = {
1053 .name_index = name_index,
1054 .name = name,
1055 .value = value,
1056 .value_len = value_len,
1057
1058 };
1059 struct ext4_xattr_ibody_find is = {
1060 .s = { .not_found = -ENODATA, },
1061 };
1062 struct ext4_xattr_block_find bs = {
1063 .s = { .not_found = -ENODATA, },
1064 };
1065 unsigned long no_expand;
1066 int error;
1067
1068 if (!name)
1069 return -EINVAL;
1070 if (strlen(name) > 255)
1071 return -ERANGE;
1072 down_write(&EXT4_I(inode)->xattr_sem);
1073 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1074 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1075
1076 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1077 if (error)
1078 goto cleanup;
1079
1080 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1081 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1082 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1083 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1084 }
1085
1086 error = ext4_xattr_ibody_find(inode, &i, &is);
1087 if (error)
1088 goto cleanup;
1089 if (is.s.not_found)
1090 error = ext4_xattr_block_find(inode, &i, &bs);
1091 if (error)
1092 goto cleanup;
1093 if (is.s.not_found && bs.s.not_found) {
1094 error = -ENODATA;
1095 if (flags & XATTR_REPLACE)
1096 goto cleanup;
1097 error = 0;
1098 if (!value)
1099 goto cleanup;
1100 } else {
1101 error = -EEXIST;
1102 if (flags & XATTR_CREATE)
1103 goto cleanup;
1104 }
1105 if (!value) {
1106 if (!is.s.not_found)
1107 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1108 else if (!bs.s.not_found)
1109 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1110 } else {
1111 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1112 if (!error && !bs.s.not_found) {
1113 i.value = NULL;
1114 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1115 } else if (error == -ENOSPC) {
1116 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1117 error = ext4_xattr_block_find(inode, &i, &bs);
1118 if (error)
1119 goto cleanup;
1120 }
1121 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1122 if (error)
1123 goto cleanup;
1124 if (!is.s.not_found) {
1125 i.value = NULL;
1126 error = ext4_xattr_ibody_set(handle, inode, &i,
1127 &is);
1128 }
1129 }
1130 }
1131 if (!error) {
1132 ext4_xattr_update_super_block(handle, inode->i_sb);
1133 inode->i_ctime = ext4_current_time(inode);
1134 if (!value)
1135 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1136 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1137 /*
1138 * The bh is consumed by ext4_mark_iloc_dirty, even with
1139 * error != 0.
1140 */
1141 is.iloc.bh = NULL;
1142 if (IS_SYNC(inode))
1143 ext4_handle_sync(handle);
1144 }
1145
1146 cleanup:
1147 brelse(is.iloc.bh);
1148 brelse(bs.bh);
1149 if (no_expand == 0)
1150 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1151 up_write(&EXT4_I(inode)->xattr_sem);
1152 return error;
1153 }
1154
1155 /*
1156 * ext4_xattr_set()
1157 *
1158 * Like ext4_xattr_set_handle, but start from an inode. This extended
1159 * attribute modification is a filesystem transaction by itself.
1160 *
1161 * Returns 0, or a negative error number on failure.
1162 */
1163 int
1164 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1165 const void *value, size_t value_len, int flags)
1166 {
1167 handle_t *handle;
1168 int error, retries = 0;
1169 int credits = ext4_jbd2_credits_xattr(inode);
1170
1171 retry:
1172 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1173 if (IS_ERR(handle)) {
1174 error = PTR_ERR(handle);
1175 } else {
1176 int error2;
1177
1178 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1179 value, value_len, flags);
1180 error2 = ext4_journal_stop(handle);
1181 if (error == -ENOSPC &&
1182 ext4_should_retry_alloc(inode->i_sb, &retries))
1183 goto retry;
1184 if (error == 0)
1185 error = error2;
1186 }
1187
1188 return error;
1189 }
1190
1191 /*
1192 * Shift the EA entries in the inode to create space for the increased
1193 * i_extra_isize.
1194 */
1195 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1196 int value_offs_shift, void *to,
1197 void *from, size_t n, int blocksize)
1198 {
1199 struct ext4_xattr_entry *last = entry;
1200 int new_offs;
1201
1202 /* Adjust the value offsets of the entries */
1203 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1204 if (!last->e_value_block && last->e_value_size) {
1205 new_offs = le16_to_cpu(last->e_value_offs) +
1206 value_offs_shift;
1207 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1208 > blocksize);
1209 last->e_value_offs = cpu_to_le16(new_offs);
1210 }
1211 }
1212 /* Shift the entries by n bytes */
1213 memmove(to, from, n);
1214 }
1215
1216 /*
1217 * Expand an inode by new_extra_isize bytes when EAs are present.
1218 * Returns 0 on success or negative error number on failure.
1219 */
1220 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1221 struct ext4_inode *raw_inode, handle_t *handle)
1222 {
1223 struct ext4_xattr_ibody_header *header;
1224 struct ext4_xattr_entry *entry, *last, *first;
1225 struct buffer_head *bh = NULL;
1226 struct ext4_xattr_ibody_find *is = NULL;
1227 struct ext4_xattr_block_find *bs = NULL;
1228 char *buffer = NULL, *b_entry_name = NULL;
1229 size_t min_offs, free;
1230 int total_ino, total_blk;
1231 void *base, *start, *end;
1232 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1233 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1234
1235 down_write(&EXT4_I(inode)->xattr_sem);
1236 retry:
1237 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1238 up_write(&EXT4_I(inode)->xattr_sem);
1239 return 0;
1240 }
1241
1242 header = IHDR(inode, raw_inode);
1243 entry = IFIRST(header);
1244
1245 /*
1246 * Check if enough free space is available in the inode to shift the
1247 * entries ahead by new_extra_isize.
1248 */
1249
1250 base = start = entry;
1251 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1252 min_offs = end - base;
1253 last = entry;
1254 total_ino = sizeof(struct ext4_xattr_ibody_header);
1255
1256 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1257 if (free >= new_extra_isize) {
1258 entry = IFIRST(header);
1259 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1260 - new_extra_isize, (void *)raw_inode +
1261 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1262 (void *)header, total_ino,
1263 inode->i_sb->s_blocksize);
1264 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1265 error = 0;
1266 goto cleanup;
1267 }
1268
1269 /*
1270 * Enough free space isn't available in the inode, check if
1271 * EA block can hold new_extra_isize bytes.
1272 */
1273 if (EXT4_I(inode)->i_file_acl) {
1274 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1275 error = -EIO;
1276 if (!bh)
1277 goto cleanup;
1278 if (ext4_xattr_check_block(inode, bh)) {
1279 EXT4_ERROR_INODE(inode, "bad block %llu",
1280 EXT4_I(inode)->i_file_acl);
1281 error = -EIO;
1282 goto cleanup;
1283 }
1284 base = BHDR(bh);
1285 first = BFIRST(bh);
1286 end = bh->b_data + bh->b_size;
1287 min_offs = end - base;
1288 free = ext4_xattr_free_space(first, &min_offs, base,
1289 &total_blk);
1290 if (free < new_extra_isize) {
1291 if (!tried_min_extra_isize && s_min_extra_isize) {
1292 tried_min_extra_isize++;
1293 new_extra_isize = s_min_extra_isize;
1294 brelse(bh);
1295 goto retry;
1296 }
1297 error = -1;
1298 goto cleanup;
1299 }
1300 } else {
1301 free = inode->i_sb->s_blocksize;
1302 }
1303
1304 while (new_extra_isize > 0) {
1305 size_t offs, size, entry_size;
1306 struct ext4_xattr_entry *small_entry = NULL;
1307 struct ext4_xattr_info i = {
1308 .value = NULL,
1309 .value_len = 0,
1310 };
1311 unsigned int total_size; /* EA entry size + value size */
1312 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1313 unsigned int min_total_size = ~0U;
1314
1315 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1316 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1317 if (!is || !bs) {
1318 error = -ENOMEM;
1319 goto cleanup;
1320 }
1321
1322 is->s.not_found = -ENODATA;
1323 bs->s.not_found = -ENODATA;
1324 is->iloc.bh = NULL;
1325 bs->bh = NULL;
1326
1327 last = IFIRST(header);
1328 /* Find the entry best suited to be pushed into EA block */
1329 entry = NULL;
1330 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1331 total_size =
1332 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1333 EXT4_XATTR_LEN(last->e_name_len);
1334 if (total_size <= free && total_size < min_total_size) {
1335 if (total_size < new_extra_isize) {
1336 small_entry = last;
1337 } else {
1338 entry = last;
1339 min_total_size = total_size;
1340 }
1341 }
1342 }
1343
1344 if (entry == NULL) {
1345 if (small_entry) {
1346 entry = small_entry;
1347 } else {
1348 if (!tried_min_extra_isize &&
1349 s_min_extra_isize) {
1350 tried_min_extra_isize++;
1351 new_extra_isize = s_min_extra_isize;
1352 goto retry;
1353 }
1354 error = -1;
1355 goto cleanup;
1356 }
1357 }
1358 offs = le16_to_cpu(entry->e_value_offs);
1359 size = le32_to_cpu(entry->e_value_size);
1360 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1361 i.name_index = entry->e_name_index,
1362 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1363 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1364 if (!buffer || !b_entry_name) {
1365 error = -ENOMEM;
1366 goto cleanup;
1367 }
1368 /* Save the entry name and the entry value */
1369 memcpy(buffer, (void *)IFIRST(header) + offs,
1370 EXT4_XATTR_SIZE(size));
1371 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1372 b_entry_name[entry->e_name_len] = '\0';
1373 i.name = b_entry_name;
1374
1375 error = ext4_get_inode_loc(inode, &is->iloc);
1376 if (error)
1377 goto cleanup;
1378
1379 error = ext4_xattr_ibody_find(inode, &i, is);
1380 if (error)
1381 goto cleanup;
1382
1383 /* Remove the chosen entry from the inode */
1384 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1385 if (error)
1386 goto cleanup;
1387
1388 entry = IFIRST(header);
1389 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1390 shift_bytes = new_extra_isize;
1391 else
1392 shift_bytes = entry_size + size;
1393 /* Adjust the offsets and shift the remaining entries ahead */
1394 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1395 shift_bytes, (void *)raw_inode +
1396 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1397 (void *)header, total_ino - entry_size,
1398 inode->i_sb->s_blocksize);
1399
1400 extra_isize += shift_bytes;
1401 new_extra_isize -= shift_bytes;
1402 EXT4_I(inode)->i_extra_isize = extra_isize;
1403
1404 i.name = b_entry_name;
1405 i.value = buffer;
1406 i.value_len = size;
1407 error = ext4_xattr_block_find(inode, &i, bs);
1408 if (error)
1409 goto cleanup;
1410
1411 /* Add entry which was removed from the inode into the block */
1412 error = ext4_xattr_block_set(handle, inode, &i, bs);
1413 if (error)
1414 goto cleanup;
1415 kfree(b_entry_name);
1416 kfree(buffer);
1417 b_entry_name = NULL;
1418 buffer = NULL;
1419 brelse(is->iloc.bh);
1420 kfree(is);
1421 kfree(bs);
1422 }
1423 brelse(bh);
1424 up_write(&EXT4_I(inode)->xattr_sem);
1425 return 0;
1426
1427 cleanup:
1428 kfree(b_entry_name);
1429 kfree(buffer);
1430 if (is)
1431 brelse(is->iloc.bh);
1432 kfree(is);
1433 kfree(bs);
1434 brelse(bh);
1435 up_write(&EXT4_I(inode)->xattr_sem);
1436 return error;
1437 }
1438
1439
1440
1441 /*
1442 * ext4_xattr_delete_inode()
1443 *
1444 * Free extended attribute resources associated with this inode. This
1445 * is called immediately before an inode is freed. We have exclusive
1446 * access to the inode.
1447 */
1448 void
1449 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1450 {
1451 struct buffer_head *bh = NULL;
1452
1453 if (!EXT4_I(inode)->i_file_acl)
1454 goto cleanup;
1455 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1456 if (!bh) {
1457 EXT4_ERROR_INODE(inode, "block %llu read error",
1458 EXT4_I(inode)->i_file_acl);
1459 goto cleanup;
1460 }
1461 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1462 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1463 EXT4_ERROR_INODE(inode, "bad block %llu",
1464 EXT4_I(inode)->i_file_acl);
1465 goto cleanup;
1466 }
1467 ext4_xattr_release_block(handle, inode, bh);
1468 EXT4_I(inode)->i_file_acl = 0;
1469
1470 cleanup:
1471 brelse(bh);
1472 }
1473
1474 /*
1475 * ext4_xattr_put_super()
1476 *
1477 * This is called when a file system is unmounted.
1478 */
1479 void
1480 ext4_xattr_put_super(struct super_block *sb)
1481 {
1482 mb_cache_shrink(sb->s_bdev);
1483 }
1484
1485 /*
1486 * ext4_xattr_cache_insert()
1487 *
1488 * Create a new entry in the extended attribute cache, and insert
1489 * it unless such an entry is already in the cache.
1490 *
1491 * Returns 0, or a negative error number on failure.
1492 */
1493 static void
1494 ext4_xattr_cache_insert(struct buffer_head *bh)
1495 {
1496 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1497 struct mb_cache_entry *ce;
1498 int error;
1499
1500 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1501 if (!ce) {
1502 ea_bdebug(bh, "out of memory");
1503 return;
1504 }
1505 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1506 if (error) {
1507 mb_cache_entry_free(ce);
1508 if (error == -EBUSY) {
1509 ea_bdebug(bh, "already in cache");
1510 error = 0;
1511 }
1512 } else {
1513 ea_bdebug(bh, "inserting [%x]", (int)hash);
1514 mb_cache_entry_release(ce);
1515 }
1516 }
1517
1518 /*
1519 * ext4_xattr_cmp()
1520 *
1521 * Compare two extended attribute blocks for equality.
1522 *
1523 * Returns 0 if the blocks are equal, 1 if they differ, and
1524 * a negative error number on errors.
1525 */
1526 static int
1527 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1528 struct ext4_xattr_header *header2)
1529 {
1530 struct ext4_xattr_entry *entry1, *entry2;
1531
1532 entry1 = ENTRY(header1+1);
1533 entry2 = ENTRY(header2+1);
1534 while (!IS_LAST_ENTRY(entry1)) {
1535 if (IS_LAST_ENTRY(entry2))
1536 return 1;
1537 if (entry1->e_hash != entry2->e_hash ||
1538 entry1->e_name_index != entry2->e_name_index ||
1539 entry1->e_name_len != entry2->e_name_len ||
1540 entry1->e_value_size != entry2->e_value_size ||
1541 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1542 return 1;
1543 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1544 return -EIO;
1545 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1546 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1547 le32_to_cpu(entry1->e_value_size)))
1548 return 1;
1549
1550 entry1 = EXT4_XATTR_NEXT(entry1);
1551 entry2 = EXT4_XATTR_NEXT(entry2);
1552 }
1553 if (!IS_LAST_ENTRY(entry2))
1554 return 1;
1555 return 0;
1556 }
1557
1558 /*
1559 * ext4_xattr_cache_find()
1560 *
1561 * Find an identical extended attribute block.
1562 *
1563 * Returns a pointer to the block found, or NULL if such a block was
1564 * not found or an error occurred.
1565 */
1566 static struct buffer_head *
1567 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1568 struct mb_cache_entry **pce)
1569 {
1570 __u32 hash = le32_to_cpu(header->h_hash);
1571 struct mb_cache_entry *ce;
1572
1573 if (!header->h_hash)
1574 return NULL; /* never share */
1575 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1576 again:
1577 ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1578 hash);
1579 while (ce) {
1580 struct buffer_head *bh;
1581
1582 if (IS_ERR(ce)) {
1583 if (PTR_ERR(ce) == -EAGAIN)
1584 goto again;
1585 break;
1586 }
1587 bh = sb_bread(inode->i_sb, ce->e_block);
1588 if (!bh) {
1589 EXT4_ERROR_INODE(inode, "block %lu read error",
1590 (unsigned long) ce->e_block);
1591 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1592 EXT4_XATTR_REFCOUNT_MAX) {
1593 ea_idebug(inode, "block %lu refcount %d>=%d",
1594 (unsigned long) ce->e_block,
1595 le32_to_cpu(BHDR(bh)->h_refcount),
1596 EXT4_XATTR_REFCOUNT_MAX);
1597 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1598 *pce = ce;
1599 return bh;
1600 }
1601 brelse(bh);
1602 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1603 }
1604 return NULL;
1605 }
1606
1607 #define NAME_HASH_SHIFT 5
1608 #define VALUE_HASH_SHIFT 16
1609
1610 /*
1611 * ext4_xattr_hash_entry()
1612 *
1613 * Compute the hash of an extended attribute.
1614 */
1615 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1616 struct ext4_xattr_entry *entry)
1617 {
1618 __u32 hash = 0;
1619 char *name = entry->e_name;
1620 int n;
1621
1622 for (n = 0; n < entry->e_name_len; n++) {
1623 hash = (hash << NAME_HASH_SHIFT) ^
1624 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1625 *name++;
1626 }
1627
1628 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1629 __le32 *value = (__le32 *)((char *)header +
1630 le16_to_cpu(entry->e_value_offs));
1631 for (n = (le32_to_cpu(entry->e_value_size) +
1632 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1633 hash = (hash << VALUE_HASH_SHIFT) ^
1634 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1635 le32_to_cpu(*value++);
1636 }
1637 }
1638 entry->e_hash = cpu_to_le32(hash);
1639 }
1640
1641 #undef NAME_HASH_SHIFT
1642 #undef VALUE_HASH_SHIFT
1643
1644 #define BLOCK_HASH_SHIFT 16
1645
1646 /*
1647 * ext4_xattr_rehash()
1648 *
1649 * Re-compute the extended attribute hash value after an entry has changed.
1650 */
1651 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1652 struct ext4_xattr_entry *entry)
1653 {
1654 struct ext4_xattr_entry *here;
1655 __u32 hash = 0;
1656
1657 ext4_xattr_hash_entry(header, entry);
1658 here = ENTRY(header+1);
1659 while (!IS_LAST_ENTRY(here)) {
1660 if (!here->e_hash) {
1661 /* Block is not shared if an entry's hash value == 0 */
1662 hash = 0;
1663 break;
1664 }
1665 hash = (hash << BLOCK_HASH_SHIFT) ^
1666 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1667 le32_to_cpu(here->e_hash);
1668 here = EXT4_XATTR_NEXT(here);
1669 }
1670 header->h_hash = cpu_to_le32(hash);
1671 }
1672
1673 #undef BLOCK_HASH_SHIFT
1674
1675 int __init
1676 ext4_init_xattr(void)
1677 {
1678 ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1679 if (!ext4_xattr_cache)
1680 return -ENOMEM;
1681 return 0;
1682 }
1683
1684 void
1685 ext4_exit_xattr(void)
1686 {
1687 if (ext4_xattr_cache)
1688 mb_cache_destroy(ext4_xattr_cache);
1689 ext4_xattr_cache = NULL;
1690 }
Linus' kernel tree