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staging: hv: Fix error checking in channel.c
[linux/fpc-iii.git] / fs / ext4 / xattr.c
blobb4c5aa8489d851ea3478c8e25106a0c87846b3f6
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 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 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 struct xattr_handler *
126 ext4_xattr_handler(int name_index)
127 {
128 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->i_sb,
232 "inode %lu: bad block %llu", inode->i_ino,
233 EXT4_I(inode)->i_file_acl);
234 error = -EIO;
235 goto cleanup;
236 }
237 ext4_xattr_cache_insert(bh);
238 entry = BFIRST(bh);
239 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
240 if (error == -EIO)
241 goto bad_block;
242 if (error)
243 goto cleanup;
244 size = le32_to_cpu(entry->e_value_size);
245 if (buffer) {
246 error = -ERANGE;
247 if (size > buffer_size)
248 goto cleanup;
249 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
250 size);
251 }
252 error = size;
253
254 cleanup:
255 brelse(bh);
256 return error;
257 }
258
259 static int
260 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
261 void *buffer, size_t buffer_size)
262 {
263 struct ext4_xattr_ibody_header *header;
264 struct ext4_xattr_entry *entry;
265 struct ext4_inode *raw_inode;
266 struct ext4_iloc iloc;
267 size_t size;
268 void *end;
269 int error;
270
271 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
272 return -ENODATA;
273 error = ext4_get_inode_loc(inode, &iloc);
274 if (error)
275 return error;
276 raw_inode = ext4_raw_inode(&iloc);
277 header = IHDR(inode, raw_inode);
278 entry = IFIRST(header);
279 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
280 error = ext4_xattr_check_names(entry, end);
281 if (error)
282 goto cleanup;
283 error = ext4_xattr_find_entry(&entry, name_index, name,
284 end - (void *)entry, 0);
285 if (error)
286 goto cleanup;
287 size = le32_to_cpu(entry->e_value_size);
288 if (buffer) {
289 error = -ERANGE;
290 if (size > buffer_size)
291 goto cleanup;
292 memcpy(buffer, (void *)IFIRST(header) +
293 le16_to_cpu(entry->e_value_offs), size);
294 }
295 error = size;
296
297 cleanup:
298 brelse(iloc.bh);
299 return error;
300 }
301
302 /*
303 * ext4_xattr_get()
304 *
305 * Copy an extended attribute into the buffer
306 * provided, or compute the buffer size required.
307 * Buffer is NULL to compute the size of the buffer required.
308 *
309 * Returns a negative error number on failure, or the number of bytes
310 * used / required on success.
311 */
312 int
313 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
314 void *buffer, size_t buffer_size)
315 {
316 int error;
317
318 down_read(&EXT4_I(inode)->xattr_sem);
319 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
320 buffer_size);
321 if (error == -ENODATA)
322 error = ext4_xattr_block_get(inode, name_index, name, buffer,
323 buffer_size);
324 up_read(&EXT4_I(inode)->xattr_sem);
325 return error;
326 }
327
328 static int
329 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
330 char *buffer, size_t buffer_size)
331 {
332 size_t rest = buffer_size;
333
334 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
335 struct xattr_handler *handler =
336 ext4_xattr_handler(entry->e_name_index);
337
338 if (handler) {
339 size_t size = handler->list(dentry, buffer, rest,
340 entry->e_name,
341 entry->e_name_len,
342 handler->flags);
343 if (buffer) {
344 if (size > rest)
345 return -ERANGE;
346 buffer += size;
347 }
348 rest -= size;
349 }
350 }
351 return buffer_size - rest;
352 }
353
354 static int
355 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
356 {
357 struct inode *inode = dentry->d_inode;
358 struct buffer_head *bh = NULL;
359 int error;
360
361 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
362 buffer, (long)buffer_size);
363
364 error = 0;
365 if (!EXT4_I(inode)->i_file_acl)
366 goto cleanup;
367 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
368 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
369 error = -EIO;
370 if (!bh)
371 goto cleanup;
372 ea_bdebug(bh, "b_count=%d, refcount=%d",
373 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
374 if (ext4_xattr_check_block(bh)) {
375 ext4_error(inode->i_sb,
376 "inode %lu: bad block %llu", inode->i_ino,
377 EXT4_I(inode)->i_file_acl);
378 error = -EIO;
379 goto cleanup;
380 }
381 ext4_xattr_cache_insert(bh);
382 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
383
384 cleanup:
385 brelse(bh);
386
387 return error;
388 }
389
390 static int
391 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
392 {
393 struct inode *inode = dentry->d_inode;
394 struct ext4_xattr_ibody_header *header;
395 struct ext4_inode *raw_inode;
396 struct ext4_iloc iloc;
397 void *end;
398 int error;
399
400 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
401 return 0;
402 error = ext4_get_inode_loc(inode, &iloc);
403 if (error)
404 return error;
405 raw_inode = ext4_raw_inode(&iloc);
406 header = IHDR(inode, raw_inode);
407 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
408 error = ext4_xattr_check_names(IFIRST(header), end);
409 if (error)
410 goto cleanup;
411 error = ext4_xattr_list_entries(dentry, IFIRST(header),
412 buffer, buffer_size);
413
414 cleanup:
415 brelse(iloc.bh);
416 return error;
417 }
418
419 /*
420 * ext4_xattr_list()
421 *
422 * Copy a list of attribute names into the buffer
423 * provided, or compute the buffer size required.
424 * Buffer is NULL to compute the size of the buffer required.
425 *
426 * Returns a negative error number on failure, or the number of bytes
427 * used / required on success.
428 */
429 static int
430 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
431 {
432 int i_error, b_error;
433
434 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
435 i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
436 if (i_error < 0) {
437 b_error = 0;
438 } else {
439 if (buffer) {
440 buffer += i_error;
441 buffer_size -= i_error;
442 }
443 b_error = ext4_xattr_block_list(dentry, buffer, buffer_size);
444 if (b_error < 0)
445 i_error = 0;
446 }
447 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
448 return i_error + b_error;
449 }
450
451 /*
452 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
453 * not set, set it.
454 */
455 static void ext4_xattr_update_super_block(handle_t *handle,
456 struct super_block *sb)
457 {
458 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
459 return;
460
461 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
462 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
463 sb->s_dirt = 1;
464 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
465 }
466 }
467
468 /*
469 * Release the xattr block BH: If the reference count is > 1, decrement
470 * it; otherwise free the block.
471 */
472 static void
473 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
474 struct buffer_head *bh)
475 {
476 struct mb_cache_entry *ce = NULL;
477 int error = 0;
478
479 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
480 error = ext4_journal_get_write_access(handle, bh);
481 if (error)
482 goto out;
483
484 lock_buffer(bh);
485 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
486 ea_bdebug(bh, "refcount now=0; freeing");
487 if (ce)
488 mb_cache_entry_free(ce);
489 get_bh(bh);
490 ext4_free_blocks(handle, inode, bh, 0, 1,
491 EXT4_FREE_BLOCKS_METADATA |
492 EXT4_FREE_BLOCKS_FORGET);
493 } else {
494 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
495 error = ext4_handle_dirty_metadata(handle, inode, bh);
496 if (IS_SYNC(inode))
497 ext4_handle_sync(handle);
498 dquot_free_block(inode, 1);
499 ea_bdebug(bh, "refcount now=%d; releasing",
500 le32_to_cpu(BHDR(bh)->h_refcount));
501 if (ce)
502 mb_cache_entry_release(ce);
503 }
504 unlock_buffer(bh);
505 out:
506 ext4_std_error(inode->i_sb, error);
507 return;
508 }
509
510 /*
511 * Find the available free space for EAs. This also returns the total number of
512 * bytes used by EA entries.
513 */
514 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
515 size_t *min_offs, void *base, int *total)
516 {
517 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
518 *total += EXT4_XATTR_LEN(last->e_name_len);
519 if (!last->e_value_block && last->e_value_size) {
520 size_t offs = le16_to_cpu(last->e_value_offs);
521 if (offs < *min_offs)
522 *min_offs = offs;
523 }
524 }
525 return (*min_offs - ((void *)last - base) - sizeof(__u32));
526 }
527
528 struct ext4_xattr_info {
529 int name_index;
530 const char *name;
531 const void *value;
532 size_t value_len;
533 };
534
535 struct ext4_xattr_search {
536 struct ext4_xattr_entry *first;
537 void *base;
538 void *end;
539 struct ext4_xattr_entry *here;
540 int not_found;
541 };
542
543 static int
544 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
545 {
546 struct ext4_xattr_entry *last;
547 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
548
549 /* Compute min_offs and last. */
550 last = s->first;
551 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
552 if (!last->e_value_block && last->e_value_size) {
553 size_t offs = le16_to_cpu(last->e_value_offs);
554 if (offs < min_offs)
555 min_offs = offs;
556 }
557 }
558 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
559 if (!s->not_found) {
560 if (!s->here->e_value_block && s->here->e_value_size) {
561 size_t size = le32_to_cpu(s->here->e_value_size);
562 free += EXT4_XATTR_SIZE(size);
563 }
564 free += EXT4_XATTR_LEN(name_len);
565 }
566 if (i->value) {
567 if (free < EXT4_XATTR_SIZE(i->value_len) ||
568 free < EXT4_XATTR_LEN(name_len) +
569 EXT4_XATTR_SIZE(i->value_len))
570 return -ENOSPC;
571 }
572
573 if (i->value && s->not_found) {
574 /* Insert the new name. */
575 size_t size = EXT4_XATTR_LEN(name_len);
576 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
577 memmove((void *)s->here + size, s->here, rest);
578 memset(s->here, 0, size);
579 s->here->e_name_index = i->name_index;
580 s->here->e_name_len = name_len;
581 memcpy(s->here->e_name, i->name, name_len);
582 } else {
583 if (!s->here->e_value_block && s->here->e_value_size) {
584 void *first_val = s->base + min_offs;
585 size_t offs = le16_to_cpu(s->here->e_value_offs);
586 void *val = s->base + offs;
587 size_t size = EXT4_XATTR_SIZE(
588 le32_to_cpu(s->here->e_value_size));
589
590 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
591 /* The old and the new value have the same
592 size. Just replace. */
593 s->here->e_value_size =
594 cpu_to_le32(i->value_len);
595 memset(val + size - EXT4_XATTR_PAD, 0,
596 EXT4_XATTR_PAD); /* Clear pad bytes. */
597 memcpy(val, i->value, i->value_len);
598 return 0;
599 }
600
601 /* Remove the old value. */
602 memmove(first_val + size, first_val, val - first_val);
603 memset(first_val, 0, size);
604 s->here->e_value_size = 0;
605 s->here->e_value_offs = 0;
606 min_offs += size;
607
608 /* Adjust all value offsets. */
609 last = s->first;
610 while (!IS_LAST_ENTRY(last)) {
611 size_t o = le16_to_cpu(last->e_value_offs);
612 if (!last->e_value_block &&
613 last->e_value_size && o < offs)
614 last->e_value_offs =
615 cpu_to_le16(o + size);
616 last = EXT4_XATTR_NEXT(last);
617 }
618 }
619 if (!i->value) {
620 /* Remove the old name. */
621 size_t size = EXT4_XATTR_LEN(name_len);
622 last = ENTRY((void *)last - size);
623 memmove(s->here, (void *)s->here + size,
624 (void *)last - (void *)s->here + sizeof(__u32));
625 memset(last, 0, size);
626 }
627 }
628
629 if (i->value) {
630 /* Insert the new value. */
631 s->here->e_value_size = cpu_to_le32(i->value_len);
632 if (i->value_len) {
633 size_t size = EXT4_XATTR_SIZE(i->value_len);
634 void *val = s->base + min_offs - size;
635 s->here->e_value_offs = cpu_to_le16(min_offs - size);
636 memset(val + size - EXT4_XATTR_PAD, 0,
637 EXT4_XATTR_PAD); /* Clear the pad bytes. */
638 memcpy(val, i->value, i->value_len);
639 }
640 }
641 return 0;
642 }
643
644 struct ext4_xattr_block_find {
645 struct ext4_xattr_search s;
646 struct buffer_head *bh;
647 };
648
649 static int
650 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
651 struct ext4_xattr_block_find *bs)
652 {
653 struct super_block *sb = inode->i_sb;
654 int error;
655
656 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
657 i->name_index, i->name, i->value, (long)i->value_len);
658
659 if (EXT4_I(inode)->i_file_acl) {
660 /* The inode already has an extended attribute block. */
661 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
662 error = -EIO;
663 if (!bs->bh)
664 goto cleanup;
665 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
666 atomic_read(&(bs->bh->b_count)),
667 le32_to_cpu(BHDR(bs->bh)->h_refcount));
668 if (ext4_xattr_check_block(bs->bh)) {
669 ext4_error(sb, "inode %lu: bad block %llu",
670 inode->i_ino, EXT4_I(inode)->i_file_acl);
671 error = -EIO;
672 goto cleanup;
673 }
674 /* Find the named attribute. */
675 bs->s.base = BHDR(bs->bh);
676 bs->s.first = BFIRST(bs->bh);
677 bs->s.end = bs->bh->b_data + bs->bh->b_size;
678 bs->s.here = bs->s.first;
679 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
680 i->name, bs->bh->b_size, 1);
681 if (error && error != -ENODATA)
682 goto cleanup;
683 bs->s.not_found = error;
684 }
685 error = 0;
686
687 cleanup:
688 return error;
689 }
690
691 static int
692 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
693 struct ext4_xattr_info *i,
694 struct ext4_xattr_block_find *bs)
695 {
696 struct super_block *sb = inode->i_sb;
697 struct buffer_head *new_bh = NULL;
698 struct ext4_xattr_search *s = &bs->s;
699 struct mb_cache_entry *ce = NULL;
700 int error = 0;
701
702 #define header(x) ((struct ext4_xattr_header *)(x))
703
704 if (i->value && i->value_len > sb->s_blocksize)
705 return -ENOSPC;
706 if (s->base) {
707 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
708 bs->bh->b_blocknr);
709 error = ext4_journal_get_write_access(handle, bs->bh);
710 if (error)
711 goto cleanup;
712 lock_buffer(bs->bh);
713
714 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
715 if (ce) {
716 mb_cache_entry_free(ce);
717 ce = NULL;
718 }
719 ea_bdebug(bs->bh, "modifying in-place");
720 error = ext4_xattr_set_entry(i, s);
721 if (!error) {
722 if (!IS_LAST_ENTRY(s->first))
723 ext4_xattr_rehash(header(s->base),
724 s->here);
725 ext4_xattr_cache_insert(bs->bh);
726 }
727 unlock_buffer(bs->bh);
728 if (error == -EIO)
729 goto bad_block;
730 if (!error)
731 error = ext4_handle_dirty_metadata(handle,
732 inode,
733 bs->bh);
734 if (error)
735 goto cleanup;
736 goto inserted;
737 } else {
738 int offset = (char *)s->here - bs->bh->b_data;
739
740 unlock_buffer(bs->bh);
741 jbd2_journal_release_buffer(handle, bs->bh);
742 if (ce) {
743 mb_cache_entry_release(ce);
744 ce = NULL;
745 }
746 ea_bdebug(bs->bh, "cloning");
747 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
748 error = -ENOMEM;
749 if (s->base == NULL)
750 goto cleanup;
751 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
752 s->first = ENTRY(header(s->base)+1);
753 header(s->base)->h_refcount = cpu_to_le32(1);
754 s->here = ENTRY(s->base + offset);
755 s->end = s->base + bs->bh->b_size;
756 }
757 } else {
758 /* Allocate a buffer where we construct the new block. */
759 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
760 /* assert(header == s->base) */
761 error = -ENOMEM;
762 if (s->base == NULL)
763 goto cleanup;
764 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
765 header(s->base)->h_blocks = cpu_to_le32(1);
766 header(s->base)->h_refcount = cpu_to_le32(1);
767 s->first = ENTRY(header(s->base)+1);
768 s->here = ENTRY(header(s->base)+1);
769 s->end = s->base + sb->s_blocksize;
770 }
771
772 error = ext4_xattr_set_entry(i, s);
773 if (error == -EIO)
774 goto bad_block;
775 if (error)
776 goto cleanup;
777 if (!IS_LAST_ENTRY(s->first))
778 ext4_xattr_rehash(header(s->base), s->here);
779
780 inserted:
781 if (!IS_LAST_ENTRY(s->first)) {
782 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
783 if (new_bh) {
784 /* We found an identical block in the cache. */
785 if (new_bh == bs->bh)
786 ea_bdebug(new_bh, "keeping");
787 else {
788 /* The old block is released after updating
789 the inode. */
790 error = dquot_alloc_block(inode, 1);
791 if (error)
792 goto cleanup;
793 error = ext4_journal_get_write_access(handle,
794 new_bh);
795 if (error)
796 goto cleanup_dquot;
797 lock_buffer(new_bh);
798 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
799 ea_bdebug(new_bh, "reusing; refcount now=%d",
800 le32_to_cpu(BHDR(new_bh)->h_refcount));
801 unlock_buffer(new_bh);
802 error = ext4_handle_dirty_metadata(handle,
803 inode,
804 new_bh);
805 if (error)
806 goto cleanup_dquot;
807 }
808 mb_cache_entry_release(ce);
809 ce = NULL;
810 } else if (bs->bh && s->base == bs->bh->b_data) {
811 /* We were modifying this block in-place. */
812 ea_bdebug(bs->bh, "keeping this block");
813 new_bh = bs->bh;
814 get_bh(new_bh);
815 } else {
816 /* We need to allocate a new block */
817 ext4_fsblk_t goal, block;
818
819 goal = ext4_group_first_block_no(sb,
820 EXT4_I(inode)->i_block_group);
821
822 /* non-extent files can't have physical blocks past 2^32 */
823 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
824 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
825
826 block = ext4_new_meta_blocks(handle, inode,
827 goal, NULL, &error);
828 if (error)
829 goto cleanup;
830
831 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
832 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
833
834 ea_idebug(inode, "creating block %d", block);
835
836 new_bh = sb_getblk(sb, block);
837 if (!new_bh) {
838 getblk_failed:
839 ext4_free_blocks(handle, inode, 0, block, 1,
840 EXT4_FREE_BLOCKS_METADATA);
841 error = -EIO;
842 goto cleanup;
843 }
844 lock_buffer(new_bh);
845 error = ext4_journal_get_create_access(handle, new_bh);
846 if (error) {
847 unlock_buffer(new_bh);
848 goto getblk_failed;
849 }
850 memcpy(new_bh->b_data, s->base, new_bh->b_size);
851 set_buffer_uptodate(new_bh);
852 unlock_buffer(new_bh);
853 ext4_xattr_cache_insert(new_bh);
854 error = ext4_handle_dirty_metadata(handle,
855 inode, new_bh);
856 if (error)
857 goto cleanup;
858 }
859 }
860
861 /* Update the inode. */
862 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
863
864 /* Drop the previous xattr block. */
865 if (bs->bh && bs->bh != new_bh)
866 ext4_xattr_release_block(handle, inode, bs->bh);
867 error = 0;
868
869 cleanup:
870 if (ce)
871 mb_cache_entry_release(ce);
872 brelse(new_bh);
873 if (!(bs->bh && s->base == bs->bh->b_data))
874 kfree(s->base);
875
876 return error;
877
878 cleanup_dquot:
879 dquot_free_block(inode, 1);
880 goto cleanup;
881
882 bad_block:
883 ext4_error(inode->i_sb, "inode %lu: bad block %llu",
884 inode->i_ino, EXT4_I(inode)->i_file_acl);
885 goto cleanup;
886
887 #undef header
888 }
889
890 struct ext4_xattr_ibody_find {
891 struct ext4_xattr_search s;
892 struct ext4_iloc iloc;
893 };
894
895 static int
896 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
897 struct ext4_xattr_ibody_find *is)
898 {
899 struct ext4_xattr_ibody_header *header;
900 struct ext4_inode *raw_inode;
901 int error;
902
903 if (EXT4_I(inode)->i_extra_isize == 0)
904 return 0;
905 raw_inode = ext4_raw_inode(&is->iloc);
906 header = IHDR(inode, raw_inode);
907 is->s.base = is->s.first = IFIRST(header);
908 is->s.here = is->s.first;
909 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
910 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
911 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
912 if (error)
913 return error;
914 /* Find the named attribute. */
915 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
916 i->name, is->s.end -
917 (void *)is->s.base, 0);
918 if (error && error != -ENODATA)
919 return error;
920 is->s.not_found = error;
921 }
922 return 0;
923 }
924
925 static int
926 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
927 struct ext4_xattr_info *i,
928 struct ext4_xattr_ibody_find *is)
929 {
930 struct ext4_xattr_ibody_header *header;
931 struct ext4_xattr_search *s = &is->s;
932 int error;
933
934 if (EXT4_I(inode)->i_extra_isize == 0)
935 return -ENOSPC;
936 error = ext4_xattr_set_entry(i, s);
937 if (error)
938 return error;
939 header = IHDR(inode, ext4_raw_inode(&is->iloc));
940 if (!IS_LAST_ENTRY(s->first)) {
941 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
942 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
943 } else {
944 header->h_magic = cpu_to_le32(0);
945 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
946 }
947 return 0;
948 }
949
950 /*
951 * ext4_xattr_set_handle()
952 *
953 * Create, replace or remove an extended attribute for this inode. Buffer
954 * is NULL to remove an existing extended attribute, and non-NULL to
955 * either replace an existing extended attribute, or create a new extended
956 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
957 * specify that an extended attribute must exist and must not exist
958 * previous to the call, respectively.
959 *
960 * Returns 0, or a negative error number on failure.
961 */
962 int
963 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
964 const char *name, const void *value, size_t value_len,
965 int flags)
966 {
967 struct ext4_xattr_info i = {
968 .name_index = name_index,
969 .name = name,
970 .value = value,
971 .value_len = value_len,
972
973 };
974 struct ext4_xattr_ibody_find is = {
975 .s = { .not_found = -ENODATA, },
976 };
977 struct ext4_xattr_block_find bs = {
978 .s = { .not_found = -ENODATA, },
979 };
980 unsigned long no_expand;
981 int error;
982
983 if (!name)
984 return -EINVAL;
985 if (strlen(name) > 255)
986 return -ERANGE;
987 down_write(&EXT4_I(inode)->xattr_sem);
988 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
989 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
990
991 error = ext4_get_inode_loc(inode, &is.iloc);
992 if (error)
993 goto cleanup;
994
995 error = ext4_journal_get_write_access(handle, is.iloc.bh);
996 if (error)
997 goto cleanup;
998
999 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1000 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1001 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1002 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1003 }
1004
1005 error = ext4_xattr_ibody_find(inode, &i, &is);
1006 if (error)
1007 goto cleanup;
1008 if (is.s.not_found)
1009 error = ext4_xattr_block_find(inode, &i, &bs);
1010 if (error)
1011 goto cleanup;
1012 if (is.s.not_found && bs.s.not_found) {
1013 error = -ENODATA;
1014 if (flags & XATTR_REPLACE)
1015 goto cleanup;
1016 error = 0;
1017 if (!value)
1018 goto cleanup;
1019 } else {
1020 error = -EEXIST;
1021 if (flags & XATTR_CREATE)
1022 goto cleanup;
1023 }
1024 if (!value) {
1025 if (!is.s.not_found)
1026 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1027 else if (!bs.s.not_found)
1028 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1029 } else {
1030 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1031 if (!error && !bs.s.not_found) {
1032 i.value = NULL;
1033 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1034 } else if (error == -ENOSPC) {
1035 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1036 error = ext4_xattr_block_find(inode, &i, &bs);
1037 if (error)
1038 goto cleanup;
1039 }
1040 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1041 if (error)
1042 goto cleanup;
1043 if (!is.s.not_found) {
1044 i.value = NULL;
1045 error = ext4_xattr_ibody_set(handle, inode, &i,
1046 &is);
1047 }
1048 }
1049 }
1050 if (!error) {
1051 ext4_xattr_update_super_block(handle, inode->i_sb);
1052 inode->i_ctime = ext4_current_time(inode);
1053 if (!value)
1054 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1055 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1056 /*
1057 * The bh is consumed by ext4_mark_iloc_dirty, even with
1058 * error != 0.
1059 */
1060 is.iloc.bh = NULL;
1061 if (IS_SYNC(inode))
1062 ext4_handle_sync(handle);
1063 }
1064
1065 cleanup:
1066 brelse(is.iloc.bh);
1067 brelse(bs.bh);
1068 if (no_expand == 0)
1069 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1070 up_write(&EXT4_I(inode)->xattr_sem);
1071 return error;
1072 }
1073
1074 /*
1075 * ext4_xattr_set()
1076 *
1077 * Like ext4_xattr_set_handle, but start from an inode. This extended
1078 * attribute modification is a filesystem transaction by itself.
1079 *
1080 * Returns 0, or a negative error number on failure.
1081 */
1082 int
1083 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1084 const void *value, size_t value_len, int flags)
1085 {
1086 handle_t *handle;
1087 int error, retries = 0;
1088
1089 retry:
1090 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1091 if (IS_ERR(handle)) {
1092 error = PTR_ERR(handle);
1093 } else {
1094 int error2;
1095
1096 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1097 value, value_len, flags);
1098 error2 = ext4_journal_stop(handle);
1099 if (error == -ENOSPC &&
1100 ext4_should_retry_alloc(inode->i_sb, &retries))
1101 goto retry;
1102 if (error == 0)
1103 error = error2;
1104 }
1105
1106 return error;
1107 }
1108
1109 /*
1110 * Shift the EA entries in the inode to create space for the increased
1111 * i_extra_isize.
1112 */
1113 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1114 int value_offs_shift, void *to,
1115 void *from, size_t n, int blocksize)
1116 {
1117 struct ext4_xattr_entry *last = entry;
1118 int new_offs;
1119
1120 /* Adjust the value offsets of the entries */
1121 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1122 if (!last->e_value_block && last->e_value_size) {
1123 new_offs = le16_to_cpu(last->e_value_offs) +
1124 value_offs_shift;
1125 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1126 > blocksize);
1127 last->e_value_offs = cpu_to_le16(new_offs);
1128 }
1129 }
1130 /* Shift the entries by n bytes */
1131 memmove(to, from, n);
1132 }
1133
1134 /*
1135 * Expand an inode by new_extra_isize bytes when EAs are present.
1136 * Returns 0 on success or negative error number on failure.
1137 */
1138 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1139 struct ext4_inode *raw_inode, handle_t *handle)
1140 {
1141 struct ext4_xattr_ibody_header *header;
1142 struct ext4_xattr_entry *entry, *last, *first;
1143 struct buffer_head *bh = NULL;
1144 struct ext4_xattr_ibody_find *is = NULL;
1145 struct ext4_xattr_block_find *bs = NULL;
1146 char *buffer = NULL, *b_entry_name = NULL;
1147 size_t min_offs, free;
1148 int total_ino, total_blk;
1149 void *base, *start, *end;
1150 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1151 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1152
1153 down_write(&EXT4_I(inode)->xattr_sem);
1154 retry:
1155 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1156 up_write(&EXT4_I(inode)->xattr_sem);
1157 return 0;
1158 }
1159
1160 header = IHDR(inode, raw_inode);
1161 entry = IFIRST(header);
1162
1163 /*
1164 * Check if enough free space is available in the inode to shift the
1165 * entries ahead by new_extra_isize.
1166 */
1167
1168 base = start = entry;
1169 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1170 min_offs = end - base;
1171 last = entry;
1172 total_ino = sizeof(struct ext4_xattr_ibody_header);
1173
1174 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1175 if (free >= new_extra_isize) {
1176 entry = IFIRST(header);
1177 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1178 - new_extra_isize, (void *)raw_inode +
1179 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1180 (void *)header, total_ino,
1181 inode->i_sb->s_blocksize);
1182 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1183 error = 0;
1184 goto cleanup;
1185 }
1186
1187 /*
1188 * Enough free space isn't available in the inode, check if
1189 * EA block can hold new_extra_isize bytes.
1190 */
1191 if (EXT4_I(inode)->i_file_acl) {
1192 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1193 error = -EIO;
1194 if (!bh)
1195 goto cleanup;
1196 if (ext4_xattr_check_block(bh)) {
1197 ext4_error(inode->i_sb, "inode %lu: bad block %llu",
1198 inode->i_ino, EXT4_I(inode)->i_file_acl);
1199 error = -EIO;
1200 goto cleanup;
1201 }
1202 base = BHDR(bh);
1203 first = BFIRST(bh);
1204 end = bh->b_data + bh->b_size;
1205 min_offs = end - base;
1206 free = ext4_xattr_free_space(first, &min_offs, base,
1207 &total_blk);
1208 if (free < new_extra_isize) {
1209 if (!tried_min_extra_isize && s_min_extra_isize) {
1210 tried_min_extra_isize++;
1211 new_extra_isize = s_min_extra_isize;
1212 brelse(bh);
1213 goto retry;
1214 }
1215 error = -1;
1216 goto cleanup;
1217 }
1218 } else {
1219 free = inode->i_sb->s_blocksize;
1220 }
1221
1222 while (new_extra_isize > 0) {
1223 size_t offs, size, entry_size;
1224 struct ext4_xattr_entry *small_entry = NULL;
1225 struct ext4_xattr_info i = {
1226 .value = NULL,
1227 .value_len = 0,
1228 };
1229 unsigned int total_size; /* EA entry size + value size */
1230 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1231 unsigned int min_total_size = ~0U;
1232
1233 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1234 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1235 if (!is || !bs) {
1236 error = -ENOMEM;
1237 goto cleanup;
1238 }
1239
1240 is->s.not_found = -ENODATA;
1241 bs->s.not_found = -ENODATA;
1242 is->iloc.bh = NULL;
1243 bs->bh = NULL;
1244
1245 last = IFIRST(header);
1246 /* Find the entry best suited to be pushed into EA block */
1247 entry = NULL;
1248 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1249 total_size =
1250 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1251 EXT4_XATTR_LEN(last->e_name_len);
1252 if (total_size <= free && total_size < min_total_size) {
1253 if (total_size < new_extra_isize) {
1254 small_entry = last;
1255 } else {
1256 entry = last;
1257 min_total_size = total_size;
1258 }
1259 }
1260 }
1261
1262 if (entry == NULL) {
1263 if (small_entry) {
1264 entry = small_entry;
1265 } else {
1266 if (!tried_min_extra_isize &&
1267 s_min_extra_isize) {
1268 tried_min_extra_isize++;
1269 new_extra_isize = s_min_extra_isize;
1270 goto retry;
1271 }
1272 error = -1;
1273 goto cleanup;
1274 }
1275 }
1276 offs = le16_to_cpu(entry->e_value_offs);
1277 size = le32_to_cpu(entry->e_value_size);
1278 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1279 i.name_index = entry->e_name_index,
1280 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1281 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1282 if (!buffer || !b_entry_name) {
1283 error = -ENOMEM;
1284 goto cleanup;
1285 }
1286 /* Save the entry name and the entry value */
1287 memcpy(buffer, (void *)IFIRST(header) + offs,
1288 EXT4_XATTR_SIZE(size));
1289 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1290 b_entry_name[entry->e_name_len] = '\0';
1291 i.name = b_entry_name;
1292
1293 error = ext4_get_inode_loc(inode, &is->iloc);
1294 if (error)
1295 goto cleanup;
1296
1297 error = ext4_xattr_ibody_find(inode, &i, is);
1298 if (error)
1299 goto cleanup;
1300
1301 /* Remove the chosen entry from the inode */
1302 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1303 if (error)
1304 goto cleanup;
1305
1306 entry = IFIRST(header);
1307 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1308 shift_bytes = new_extra_isize;
1309 else
1310 shift_bytes = entry_size + size;
1311 /* Adjust the offsets and shift the remaining entries ahead */
1312 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1313 shift_bytes, (void *)raw_inode +
1314 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1315 (void *)header, total_ino - entry_size,
1316 inode->i_sb->s_blocksize);
1317
1318 extra_isize += shift_bytes;
1319 new_extra_isize -= shift_bytes;
1320 EXT4_I(inode)->i_extra_isize = extra_isize;
1321
1322 i.name = b_entry_name;
1323 i.value = buffer;
1324 i.value_len = size;
1325 error = ext4_xattr_block_find(inode, &i, bs);
1326 if (error)
1327 goto cleanup;
1328
1329 /* Add entry which was removed from the inode into the block */
1330 error = ext4_xattr_block_set(handle, inode, &i, bs);
1331 if (error)
1332 goto cleanup;
1333 kfree(b_entry_name);
1334 kfree(buffer);
1335 b_entry_name = NULL;
1336 buffer = NULL;
1337 brelse(is->iloc.bh);
1338 kfree(is);
1339 kfree(bs);
1340 }
1341 brelse(bh);
1342 up_write(&EXT4_I(inode)->xattr_sem);
1343 return 0;
1344
1345 cleanup:
1346 kfree(b_entry_name);
1347 kfree(buffer);
1348 if (is)
1349 brelse(is->iloc.bh);
1350 kfree(is);
1351 kfree(bs);
1352 brelse(bh);
1353 up_write(&EXT4_I(inode)->xattr_sem);
1354 return error;
1355 }
1356
1357
1358
1359 /*
1360 * ext4_xattr_delete_inode()
1361 *
1362 * Free extended attribute resources associated with this inode. This
1363 * is called immediately before an inode is freed. We have exclusive
1364 * access to the inode.
1365 */
1366 void
1367 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1368 {
1369 struct buffer_head *bh = NULL;
1370
1371 if (!EXT4_I(inode)->i_file_acl)
1372 goto cleanup;
1373 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1374 if (!bh) {
1375 ext4_error(inode->i_sb, "inode %lu: block %llu read error",
1376 inode->i_ino, EXT4_I(inode)->i_file_acl);
1377 goto cleanup;
1378 }
1379 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1380 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1381 ext4_error(inode->i_sb, "inode %lu: bad block %llu",
1382 inode->i_ino, EXT4_I(inode)->i_file_acl);
1383 goto cleanup;
1384 }
1385 ext4_xattr_release_block(handle, inode, bh);
1386 EXT4_I(inode)->i_file_acl = 0;
1387
1388 cleanup:
1389 brelse(bh);
1390 }
1391
1392 /*
1393 * ext4_xattr_put_super()
1394 *
1395 * This is called when a file system is unmounted.
1396 */
1397 void
1398 ext4_xattr_put_super(struct super_block *sb)
1399 {
1400 mb_cache_shrink(sb->s_bdev);
1401 }
1402
1403 /*
1404 * ext4_xattr_cache_insert()
1405 *
1406 * Create a new entry in the extended attribute cache, and insert
1407 * it unless such an entry is already in the cache.
1408 *
1409 * Returns 0, or a negative error number on failure.
1410 */
1411 static void
1412 ext4_xattr_cache_insert(struct buffer_head *bh)
1413 {
1414 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1415 struct mb_cache_entry *ce;
1416 int error;
1417
1418 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1419 if (!ce) {
1420 ea_bdebug(bh, "out of memory");
1421 return;
1422 }
1423 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1424 if (error) {
1425 mb_cache_entry_free(ce);
1426 if (error == -EBUSY) {
1427 ea_bdebug(bh, "already in cache");
1428 error = 0;
1429 }
1430 } else {
1431 ea_bdebug(bh, "inserting [%x]", (int)hash);
1432 mb_cache_entry_release(ce);
1433 }
1434 }
1435
1436 /*
1437 * ext4_xattr_cmp()
1438 *
1439 * Compare two extended attribute blocks for equality.
1440 *
1441 * Returns 0 if the blocks are equal, 1 if they differ, and
1442 * a negative error number on errors.
1443 */
1444 static int
1445 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1446 struct ext4_xattr_header *header2)
1447 {
1448 struct ext4_xattr_entry *entry1, *entry2;
1449
1450 entry1 = ENTRY(header1+1);
1451 entry2 = ENTRY(header2+1);
1452 while (!IS_LAST_ENTRY(entry1)) {
1453 if (IS_LAST_ENTRY(entry2))
1454 return 1;
1455 if (entry1->e_hash != entry2->e_hash ||
1456 entry1->e_name_index != entry2->e_name_index ||
1457 entry1->e_name_len != entry2->e_name_len ||
1458 entry1->e_value_size != entry2->e_value_size ||
1459 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1460 return 1;
1461 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1462 return -EIO;
1463 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1464 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1465 le32_to_cpu(entry1->e_value_size)))
1466 return 1;
1467
1468 entry1 = EXT4_XATTR_NEXT(entry1);
1469 entry2 = EXT4_XATTR_NEXT(entry2);
1470 }
1471 if (!IS_LAST_ENTRY(entry2))
1472 return 1;
1473 return 0;
1474 }
1475
1476 /*
1477 * ext4_xattr_cache_find()
1478 *
1479 * Find an identical extended attribute block.
1480 *
1481 * Returns a pointer to the block found, or NULL if such a block was
1482 * not found or an error occurred.
1483 */
1484 static struct buffer_head *
1485 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1486 struct mb_cache_entry **pce)
1487 {
1488 __u32 hash = le32_to_cpu(header->h_hash);
1489 struct mb_cache_entry *ce;
1490
1491 if (!header->h_hash)
1492 return NULL; /* never share */
1493 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1494 again:
1495 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1496 inode->i_sb->s_bdev, hash);
1497 while (ce) {
1498 struct buffer_head *bh;
1499
1500 if (IS_ERR(ce)) {
1501 if (PTR_ERR(ce) == -EAGAIN)
1502 goto again;
1503 break;
1504 }
1505 bh = sb_bread(inode->i_sb, ce->e_block);
1506 if (!bh) {
1507 ext4_error(inode->i_sb,
1508 "inode %lu: block %lu read error",
1509 inode->i_ino, (unsigned long) ce->e_block);
1510 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1511 EXT4_XATTR_REFCOUNT_MAX) {
1512 ea_idebug(inode, "block %lu refcount %d>=%d",
1513 (unsigned long) ce->e_block,
1514 le32_to_cpu(BHDR(bh)->h_refcount),
1515 EXT4_XATTR_REFCOUNT_MAX);
1516 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1517 *pce = ce;
1518 return bh;
1519 }
1520 brelse(bh);
1521 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1522 }
1523 return NULL;
1524 }
1525
1526 #define NAME_HASH_SHIFT 5
1527 #define VALUE_HASH_SHIFT 16
1528
1529 /*
1530 * ext4_xattr_hash_entry()
1531 *
1532 * Compute the hash of an extended attribute.
1533 */
1534 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1535 struct ext4_xattr_entry *entry)
1536 {
1537 __u32 hash = 0;
1538 char *name = entry->e_name;
1539 int n;
1540
1541 for (n = 0; n < entry->e_name_len; n++) {
1542 hash = (hash << NAME_HASH_SHIFT) ^
1543 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1544 *name++;
1545 }
1546
1547 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1548 __le32 *value = (__le32 *)((char *)header +
1549 le16_to_cpu(entry->e_value_offs));
1550 for (n = (le32_to_cpu(entry->e_value_size) +
1551 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1552 hash = (hash << VALUE_HASH_SHIFT) ^
1553 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1554 le32_to_cpu(*value++);
1555 }
1556 }
1557 entry->e_hash = cpu_to_le32(hash);
1558 }
1559
1560 #undef NAME_HASH_SHIFT
1561 #undef VALUE_HASH_SHIFT
1562
1563 #define BLOCK_HASH_SHIFT 16
1564
1565 /*
1566 * ext4_xattr_rehash()
1567 *
1568 * Re-compute the extended attribute hash value after an entry has changed.
1569 */
1570 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1571 struct ext4_xattr_entry *entry)
1572 {
1573 struct ext4_xattr_entry *here;
1574 __u32 hash = 0;
1575
1576 ext4_xattr_hash_entry(header, entry);
1577 here = ENTRY(header+1);
1578 while (!IS_LAST_ENTRY(here)) {
1579 if (!here->e_hash) {
1580 /* Block is not shared if an entry's hash value == 0 */
1581 hash = 0;
1582 break;
1583 }
1584 hash = (hash << BLOCK_HASH_SHIFT) ^
1585 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1586 le32_to_cpu(here->e_hash);
1587 here = EXT4_XATTR_NEXT(here);
1588 }
1589 header->h_hash = cpu_to_le32(hash);
1590 }
1591
1592 #undef BLOCK_HASH_SHIFT
1593
1594 int __init
1595 init_ext4_xattr(void)
1596 {
1597 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1598 sizeof(struct mb_cache_entry) +
1599 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1600 if (!ext4_xattr_cache)
1601 return -ENOMEM;
1602 return 0;
1603 }
1604
1605 void
1606 exit_ext4_xattr(void)
1607 {
1608 if (ext4_xattr_cache)
1609 mb_cache_destroy(ext4_xattr_cache);
1610 ext4_xattr_cache = NULL;
1611 }
Linux with added FPC-III support