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[mirror_ubuntu-bionic-kernel.git] / fs / ext4 / xattr.c
1 /*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16 /*
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53 #include <linux/init.h>
54 #include <linux/fs.h>
55 #include <linux/slab.h>
56 #include <linux/ext4_jbd2.h>
57 #include <linux/ext4_fs.h>
58 #include <linux/mbcache.h>
59 #include <linux/quotaops.h>
60 #include <linux/rwsem.h>
61 #include "xattr.h"
62 #include "acl.h"
63
64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
68
69 #ifdef EXT4_XATTR_DEBUG
70 # define ea_idebug(inode, f...) do { \
71 printk(KERN_DEBUG "inode %s:%lu: ", \
72 inode->i_sb->s_id, inode->i_ino); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76 # define ea_bdebug(bh, f...) do { \
77 char b[BDEVNAME_SIZE]; \
78 printk(KERN_DEBUG "block %s:%lu: ", \
79 bdevname(bh->b_bdev, b), \
80 (unsigned long) bh->b_blocknr); \
81 printk(f); \
82 printk("\n"); \
83 } while (0)
84 #else
85 # define ea_idebug(f...)
86 # define ea_bdebug(f...)
87 #endif
88
89 static void ext4_xattr_cache_insert(struct buffer_head *);
90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
91 struct ext4_xattr_header *,
92 struct mb_cache_entry **);
93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
94 struct ext4_xattr_entry *);
95
96 static struct mb_cache *ext4_xattr_cache;
97
98 static struct xattr_handler *ext4_xattr_handler_map[] = {
99 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
100 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
101 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
102 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
103 #endif
104 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
105 #ifdef CONFIG_EXT4DEV_FS_SECURITY
106 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
107 #endif
108 };
109
110 struct xattr_handler *ext4_xattr_handlers[] = {
111 &ext4_xattr_user_handler,
112 &ext4_xattr_trusted_handler,
113 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
114 &ext4_xattr_acl_access_handler,
115 &ext4_xattr_acl_default_handler,
116 #endif
117 #ifdef CONFIG_EXT4DEV_FS_SECURITY
118 &ext4_xattr_security_handler,
119 #endif
120 NULL
121 };
122
123 static inline struct xattr_handler *
124 ext4_xattr_handler(int name_index)
125 {
126 struct xattr_handler *handler = NULL;
127
128 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
129 handler = ext4_xattr_handler_map[name_index];
130 return handler;
131 }
132
133 /*
134 * Inode operation listxattr()
135 *
136 * dentry->d_inode->i_mutex: don't care
137 */
138 ssize_t
139 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
140 {
141 return ext4_xattr_list(dentry->d_inode, buffer, size);
142 }
143
144 static int
145 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
146 {
147 while (!IS_LAST_ENTRY(entry)) {
148 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
149 if ((void *)next >= end)
150 return -EIO;
151 entry = next;
152 }
153 return 0;
154 }
155
156 static inline int
157 ext4_xattr_check_block(struct buffer_head *bh)
158 {
159 int error;
160
161 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
162 BHDR(bh)->h_blocks != cpu_to_le32(1))
163 return -EIO;
164 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
165 return error;
166 }
167
168 static inline int
169 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
170 {
171 size_t value_size = le32_to_cpu(entry->e_value_size);
172
173 if (entry->e_value_block != 0 || value_size > size ||
174 le16_to_cpu(entry->e_value_offs) + value_size > size)
175 return -EIO;
176 return 0;
177 }
178
179 static int
180 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
181 const char *name, size_t size, int sorted)
182 {
183 struct ext4_xattr_entry *entry;
184 size_t name_len;
185 int cmp = 1;
186
187 if (name == NULL)
188 return -EINVAL;
189 name_len = strlen(name);
190 entry = *pentry;
191 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
192 cmp = name_index - entry->e_name_index;
193 if (!cmp)
194 cmp = name_len - entry->e_name_len;
195 if (!cmp)
196 cmp = memcmp(name, entry->e_name, name_len);
197 if (cmp <= 0 && (sorted || cmp == 0))
198 break;
199 }
200 *pentry = entry;
201 if (!cmp && ext4_xattr_check_entry(entry, size))
202 return -EIO;
203 return cmp ? -ENODATA : 0;
204 }
205
206 static int
207 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
208 void *buffer, size_t buffer_size)
209 {
210 struct buffer_head *bh = NULL;
211 struct ext4_xattr_entry *entry;
212 size_t size;
213 int error;
214
215 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
216 name_index, name, buffer, (long)buffer_size);
217
218 error = -ENODATA;
219 if (!EXT4_I(inode)->i_file_acl)
220 goto cleanup;
221 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
222 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
223 if (!bh)
224 goto cleanup;
225 ea_bdebug(bh, "b_count=%d, refcount=%d",
226 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
227 if (ext4_xattr_check_block(bh)) {
228 bad_block: ext4_error(inode->i_sb, __FUNCTION__,
229 "inode %lu: bad block %llu", inode->i_ino,
230 EXT4_I(inode)->i_file_acl);
231 error = -EIO;
232 goto cleanup;
233 }
234 ext4_xattr_cache_insert(bh);
235 entry = BFIRST(bh);
236 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
237 if (error == -EIO)
238 goto bad_block;
239 if (error)
240 goto cleanup;
241 size = le32_to_cpu(entry->e_value_size);
242 if (buffer) {
243 error = -ERANGE;
244 if (size > buffer_size)
245 goto cleanup;
246 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
247 size);
248 }
249 error = size;
250
251 cleanup:
252 brelse(bh);
253 return error;
254 }
255
256 static int
257 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
258 void *buffer, size_t buffer_size)
259 {
260 struct ext4_xattr_ibody_header *header;
261 struct ext4_xattr_entry *entry;
262 struct ext4_inode *raw_inode;
263 struct ext4_iloc iloc;
264 size_t size;
265 void *end;
266 int error;
267
268 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
269 return -ENODATA;
270 error = ext4_get_inode_loc(inode, &iloc);
271 if (error)
272 return error;
273 raw_inode = ext4_raw_inode(&iloc);
274 header = IHDR(inode, raw_inode);
275 entry = IFIRST(header);
276 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
277 error = ext4_xattr_check_names(entry, end);
278 if (error)
279 goto cleanup;
280 error = ext4_xattr_find_entry(&entry, name_index, name,
281 end - (void *)entry, 0);
282 if (error)
283 goto cleanup;
284 size = le32_to_cpu(entry->e_value_size);
285 if (buffer) {
286 error = -ERANGE;
287 if (size > buffer_size)
288 goto cleanup;
289 memcpy(buffer, (void *)IFIRST(header) +
290 le16_to_cpu(entry->e_value_offs), size);
291 }
292 error = size;
293
294 cleanup:
295 brelse(iloc.bh);
296 return error;
297 }
298
299 /*
300 * ext4_xattr_get()
301 *
302 * Copy an extended attribute into the buffer
303 * provided, or compute the buffer size required.
304 * Buffer is NULL to compute the size of the buffer required.
305 *
306 * Returns a negative error number on failure, or the number of bytes
307 * used / required on success.
308 */
309 int
310 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
311 void *buffer, size_t buffer_size)
312 {
313 int error;
314
315 down_read(&EXT4_I(inode)->xattr_sem);
316 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
317 buffer_size);
318 if (error == -ENODATA)
319 error = ext4_xattr_block_get(inode, name_index, name, buffer,
320 buffer_size);
321 up_read(&EXT4_I(inode)->xattr_sem);
322 return error;
323 }
324
325 static int
326 ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry,
327 char *buffer, size_t buffer_size)
328 {
329 size_t rest = buffer_size;
330
331 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
332 struct xattr_handler *handler =
333 ext4_xattr_handler(entry->e_name_index);
334
335 if (handler) {
336 size_t size = handler->list(inode, buffer, rest,
337 entry->e_name,
338 entry->e_name_len);
339 if (buffer) {
340 if (size > rest)
341 return -ERANGE;
342 buffer += size;
343 }
344 rest -= size;
345 }
346 }
347 return buffer_size - rest;
348 }
349
350 static int
351 ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
352 {
353 struct buffer_head *bh = NULL;
354 int error;
355
356 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
357 buffer, (long)buffer_size);
358
359 error = 0;
360 if (!EXT4_I(inode)->i_file_acl)
361 goto cleanup;
362 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
363 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
364 error = -EIO;
365 if (!bh)
366 goto cleanup;
367 ea_bdebug(bh, "b_count=%d, refcount=%d",
368 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
369 if (ext4_xattr_check_block(bh)) {
370 ext4_error(inode->i_sb, __FUNCTION__,
371 "inode %lu: bad block %llu", inode->i_ino,
372 EXT4_I(inode)->i_file_acl);
373 error = -EIO;
374 goto cleanup;
375 }
376 ext4_xattr_cache_insert(bh);
377 error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
378
379 cleanup:
380 brelse(bh);
381
382 return error;
383 }
384
385 static int
386 ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
387 {
388 struct ext4_xattr_ibody_header *header;
389 struct ext4_inode *raw_inode;
390 struct ext4_iloc iloc;
391 void *end;
392 int error;
393
394 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
395 return 0;
396 error = ext4_get_inode_loc(inode, &iloc);
397 if (error)
398 return error;
399 raw_inode = ext4_raw_inode(&iloc);
400 header = IHDR(inode, raw_inode);
401 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
402 error = ext4_xattr_check_names(IFIRST(header), end);
403 if (error)
404 goto cleanup;
405 error = ext4_xattr_list_entries(inode, IFIRST(header),
406 buffer, buffer_size);
407
408 cleanup:
409 brelse(iloc.bh);
410 return error;
411 }
412
413 /*
414 * ext4_xattr_list()
415 *
416 * Copy a list of attribute names into the buffer
417 * provided, or compute the buffer size required.
418 * Buffer is NULL to compute the size of the buffer required.
419 *
420 * Returns a negative error number on failure, or the number of bytes
421 * used / required on success.
422 */
423 int
424 ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
425 {
426 int i_error, b_error;
427
428 down_read(&EXT4_I(inode)->xattr_sem);
429 i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size);
430 if (i_error < 0) {
431 b_error = 0;
432 } else {
433 if (buffer) {
434 buffer += i_error;
435 buffer_size -= i_error;
436 }
437 b_error = ext4_xattr_block_list(inode, buffer, buffer_size);
438 if (b_error < 0)
439 i_error = 0;
440 }
441 up_read(&EXT4_I(inode)->xattr_sem);
442 return i_error + b_error;
443 }
444
445 /*
446 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
447 * not set, set it.
448 */
449 static void ext4_xattr_update_super_block(handle_t *handle,
450 struct super_block *sb)
451 {
452 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
453 return;
454
455 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
456 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
457 sb->s_dirt = 1;
458 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
459 }
460 }
461
462 /*
463 * Release the xattr block BH: If the reference count is > 1, decrement
464 * it; otherwise free the block.
465 */
466 static void
467 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
468 struct buffer_head *bh)
469 {
470 struct mb_cache_entry *ce = NULL;
471 int error = 0;
472
473 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
474 error = ext4_journal_get_write_access(handle, bh);
475 if (error)
476 goto out;
477
478 lock_buffer(bh);
479 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
480 ea_bdebug(bh, "refcount now=0; freeing");
481 if (ce)
482 mb_cache_entry_free(ce);
483 ext4_free_blocks(handle, inode, bh->b_blocknr, 1);
484 get_bh(bh);
485 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
486 } else {
487 BHDR(bh)->h_refcount = cpu_to_le32(
488 le32_to_cpu(BHDR(bh)->h_refcount) - 1);
489 error = ext4_journal_dirty_metadata(handle, bh);
490 if (IS_SYNC(inode))
491 handle->h_sync = 1;
492 DQUOT_FREE_BLOCK(inode, 1);
493 ea_bdebug(bh, "refcount now=%d; releasing",
494 le32_to_cpu(BHDR(bh)->h_refcount));
495 if (ce)
496 mb_cache_entry_release(ce);
497 }
498 unlock_buffer(bh);
499 out:
500 ext4_std_error(inode->i_sb, error);
501 return;
502 }
503
504 /*
505 * Find the available free space for EAs. This also returns the total number of
506 * bytes used by EA entries.
507 */
508 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
509 size_t *min_offs, void *base, int *total)
510 {
511 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
512 *total += EXT4_XATTR_LEN(last->e_name_len);
513 if (!last->e_value_block && last->e_value_size) {
514 size_t offs = le16_to_cpu(last->e_value_offs);
515 if (offs < *min_offs)
516 *min_offs = offs;
517 }
518 }
519 return (*min_offs - ((void *)last - base) - sizeof(__u32));
520 }
521
522 struct ext4_xattr_info {
523 int name_index;
524 const char *name;
525 const void *value;
526 size_t value_len;
527 };
528
529 struct ext4_xattr_search {
530 struct ext4_xattr_entry *first;
531 void *base;
532 void *end;
533 struct ext4_xattr_entry *here;
534 int not_found;
535 };
536
537 static int
538 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
539 {
540 struct ext4_xattr_entry *last;
541 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
542
543 /* Compute min_offs and last. */
544 last = s->first;
545 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
546 if (!last->e_value_block && last->e_value_size) {
547 size_t offs = le16_to_cpu(last->e_value_offs);
548 if (offs < min_offs)
549 min_offs = offs;
550 }
551 }
552 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
553 if (!s->not_found) {
554 if (!s->here->e_value_block && s->here->e_value_size) {
555 size_t size = le32_to_cpu(s->here->e_value_size);
556 free += EXT4_XATTR_SIZE(size);
557 }
558 free += EXT4_XATTR_LEN(name_len);
559 }
560 if (i->value) {
561 if (free < EXT4_XATTR_SIZE(i->value_len) ||
562 free < EXT4_XATTR_LEN(name_len) +
563 EXT4_XATTR_SIZE(i->value_len))
564 return -ENOSPC;
565 }
566
567 if (i->value && s->not_found) {
568 /* Insert the new name. */
569 size_t size = EXT4_XATTR_LEN(name_len);
570 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
571 memmove((void *)s->here + size, s->here, rest);
572 memset(s->here, 0, size);
573 s->here->e_name_index = i->name_index;
574 s->here->e_name_len = name_len;
575 memcpy(s->here->e_name, i->name, name_len);
576 } else {
577 if (!s->here->e_value_block && s->here->e_value_size) {
578 void *first_val = s->base + min_offs;
579 size_t offs = le16_to_cpu(s->here->e_value_offs);
580 void *val = s->base + offs;
581 size_t size = EXT4_XATTR_SIZE(
582 le32_to_cpu(s->here->e_value_size));
583
584 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
585 /* The old and the new value have the same
586 size. Just replace. */
587 s->here->e_value_size =
588 cpu_to_le32(i->value_len);
589 memset(val + size - EXT4_XATTR_PAD, 0,
590 EXT4_XATTR_PAD); /* Clear pad bytes. */
591 memcpy(val, i->value, i->value_len);
592 return 0;
593 }
594
595 /* Remove the old value. */
596 memmove(first_val + size, first_val, val - first_val);
597 memset(first_val, 0, size);
598 s->here->e_value_size = 0;
599 s->here->e_value_offs = 0;
600 min_offs += size;
601
602 /* Adjust all value offsets. */
603 last = s->first;
604 while (!IS_LAST_ENTRY(last)) {
605 size_t o = le16_to_cpu(last->e_value_offs);
606 if (!last->e_value_block &&
607 last->e_value_size && o < offs)
608 last->e_value_offs =
609 cpu_to_le16(o + size);
610 last = EXT4_XATTR_NEXT(last);
611 }
612 }
613 if (!i->value) {
614 /* Remove the old name. */
615 size_t size = EXT4_XATTR_LEN(name_len);
616 last = ENTRY((void *)last - size);
617 memmove(s->here, (void *)s->here + size,
618 (void *)last - (void *)s->here + sizeof(__u32));
619 memset(last, 0, size);
620 }
621 }
622
623 if (i->value) {
624 /* Insert the new value. */
625 s->here->e_value_size = cpu_to_le32(i->value_len);
626 if (i->value_len) {
627 size_t size = EXT4_XATTR_SIZE(i->value_len);
628 void *val = s->base + min_offs - size;
629 s->here->e_value_offs = cpu_to_le16(min_offs - size);
630 memset(val + size - EXT4_XATTR_PAD, 0,
631 EXT4_XATTR_PAD); /* Clear the pad bytes. */
632 memcpy(val, i->value, i->value_len);
633 }
634 }
635 return 0;
636 }
637
638 struct ext4_xattr_block_find {
639 struct ext4_xattr_search s;
640 struct buffer_head *bh;
641 };
642
643 static int
644 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
645 struct ext4_xattr_block_find *bs)
646 {
647 struct super_block *sb = inode->i_sb;
648 int error;
649
650 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
651 i->name_index, i->name, i->value, (long)i->value_len);
652
653 if (EXT4_I(inode)->i_file_acl) {
654 /* The inode already has an extended attribute block. */
655 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
656 error = -EIO;
657 if (!bs->bh)
658 goto cleanup;
659 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
660 atomic_read(&(bs->bh->b_count)),
661 le32_to_cpu(BHDR(bs->bh)->h_refcount));
662 if (ext4_xattr_check_block(bs->bh)) {
663 ext4_error(sb, __FUNCTION__,
664 "inode %lu: bad block %llu", inode->i_ino,
665 EXT4_I(inode)->i_file_acl);
666 error = -EIO;
667 goto cleanup;
668 }
669 /* Find the named attribute. */
670 bs->s.base = BHDR(bs->bh);
671 bs->s.first = BFIRST(bs->bh);
672 bs->s.end = bs->bh->b_data + bs->bh->b_size;
673 bs->s.here = bs->s.first;
674 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
675 i->name, bs->bh->b_size, 1);
676 if (error && error != -ENODATA)
677 goto cleanup;
678 bs->s.not_found = error;
679 }
680 error = 0;
681
682 cleanup:
683 return error;
684 }
685
686 static int
687 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
688 struct ext4_xattr_info *i,
689 struct ext4_xattr_block_find *bs)
690 {
691 struct super_block *sb = inode->i_sb;
692 struct buffer_head *new_bh = NULL;
693 struct ext4_xattr_search *s = &bs->s;
694 struct mb_cache_entry *ce = NULL;
695 int error = 0;
696
697 #define header(x) ((struct ext4_xattr_header *)(x))
698
699 if (i->value && i->value_len > sb->s_blocksize)
700 return -ENOSPC;
701 if (s->base) {
702 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
703 bs->bh->b_blocknr);
704 error = ext4_journal_get_write_access(handle, bs->bh);
705 if (error)
706 goto cleanup;
707 lock_buffer(bs->bh);
708
709 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
710 if (ce) {
711 mb_cache_entry_free(ce);
712 ce = NULL;
713 }
714 ea_bdebug(bs->bh, "modifying in-place");
715 error = ext4_xattr_set_entry(i, s);
716 if (!error) {
717 if (!IS_LAST_ENTRY(s->first))
718 ext4_xattr_rehash(header(s->base),
719 s->here);
720 ext4_xattr_cache_insert(bs->bh);
721 }
722 unlock_buffer(bs->bh);
723 if (error == -EIO)
724 goto bad_block;
725 if (!error)
726 error = ext4_journal_dirty_metadata(handle,
727 bs->bh);
728 if (error)
729 goto cleanup;
730 goto inserted;
731 } else {
732 int offset = (char *)s->here - bs->bh->b_data;
733
734 unlock_buffer(bs->bh);
735 jbd2_journal_release_buffer(handle, bs->bh);
736 if (ce) {
737 mb_cache_entry_release(ce);
738 ce = NULL;
739 }
740 ea_bdebug(bs->bh, "cloning");
741 s->base = kmalloc(bs->bh->b_size, GFP_KERNEL);
742 error = -ENOMEM;
743 if (s->base == NULL)
744 goto cleanup;
745 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
746 s->first = ENTRY(header(s->base)+1);
747 header(s->base)->h_refcount = cpu_to_le32(1);
748 s->here = ENTRY(s->base + offset);
749 s->end = s->base + bs->bh->b_size;
750 }
751 } else {
752 /* Allocate a buffer where we construct the new block. */
753 s->base = kzalloc(sb->s_blocksize, GFP_KERNEL);
754 /* assert(header == s->base) */
755 error = -ENOMEM;
756 if (s->base == NULL)
757 goto cleanup;
758 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
759 header(s->base)->h_blocks = cpu_to_le32(1);
760 header(s->base)->h_refcount = cpu_to_le32(1);
761 s->first = ENTRY(header(s->base)+1);
762 s->here = ENTRY(header(s->base)+1);
763 s->end = s->base + sb->s_blocksize;
764 }
765
766 error = ext4_xattr_set_entry(i, s);
767 if (error == -EIO)
768 goto bad_block;
769 if (error)
770 goto cleanup;
771 if (!IS_LAST_ENTRY(s->first))
772 ext4_xattr_rehash(header(s->base), s->here);
773
774 inserted:
775 if (!IS_LAST_ENTRY(s->first)) {
776 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
777 if (new_bh) {
778 /* We found an identical block in the cache. */
779 if (new_bh == bs->bh)
780 ea_bdebug(new_bh, "keeping");
781 else {
782 /* The old block is released after updating
783 the inode. */
784 error = -EDQUOT;
785 if (DQUOT_ALLOC_BLOCK(inode, 1))
786 goto cleanup;
787 error = ext4_journal_get_write_access(handle,
788 new_bh);
789 if (error)
790 goto cleanup_dquot;
791 lock_buffer(new_bh);
792 BHDR(new_bh)->h_refcount = cpu_to_le32(1 +
793 le32_to_cpu(BHDR(new_bh)->h_refcount));
794 ea_bdebug(new_bh, "reusing; refcount now=%d",
795 le32_to_cpu(BHDR(new_bh)->h_refcount));
796 unlock_buffer(new_bh);
797 error = ext4_journal_dirty_metadata(handle,
798 new_bh);
799 if (error)
800 goto cleanup_dquot;
801 }
802 mb_cache_entry_release(ce);
803 ce = NULL;
804 } else if (bs->bh && s->base == bs->bh->b_data) {
805 /* We were modifying this block in-place. */
806 ea_bdebug(bs->bh, "keeping this block");
807 new_bh = bs->bh;
808 get_bh(new_bh);
809 } else {
810 /* We need to allocate a new block */
811 ext4_fsblk_t goal = le32_to_cpu(
812 EXT4_SB(sb)->s_es->s_first_data_block) +
813 (ext4_fsblk_t)EXT4_I(inode)->i_block_group *
814 EXT4_BLOCKS_PER_GROUP(sb);
815 ext4_fsblk_t block = ext4_new_block(handle, inode,
816 goal, &error);
817 if (error)
818 goto cleanup;
819 ea_idebug(inode, "creating block %d", block);
820
821 new_bh = sb_getblk(sb, block);
822 if (!new_bh) {
823 getblk_failed:
824 ext4_free_blocks(handle, inode, block, 1);
825 error = -EIO;
826 goto cleanup;
827 }
828 lock_buffer(new_bh);
829 error = ext4_journal_get_create_access(handle, new_bh);
830 if (error) {
831 unlock_buffer(new_bh);
832 goto getblk_failed;
833 }
834 memcpy(new_bh->b_data, s->base, new_bh->b_size);
835 set_buffer_uptodate(new_bh);
836 unlock_buffer(new_bh);
837 ext4_xattr_cache_insert(new_bh);
838 error = ext4_journal_dirty_metadata(handle, new_bh);
839 if (error)
840 goto cleanup;
841 }
842 }
843
844 /* Update the inode. */
845 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
846
847 /* Drop the previous xattr block. */
848 if (bs->bh && bs->bh != new_bh)
849 ext4_xattr_release_block(handle, inode, bs->bh);
850 error = 0;
851
852 cleanup:
853 if (ce)
854 mb_cache_entry_release(ce);
855 brelse(new_bh);
856 if (!(bs->bh && s->base == bs->bh->b_data))
857 kfree(s->base);
858
859 return error;
860
861 cleanup_dquot:
862 DQUOT_FREE_BLOCK(inode, 1);
863 goto cleanup;
864
865 bad_block:
866 ext4_error(inode->i_sb, __FUNCTION__,
867 "inode %lu: bad block %llu", inode->i_ino,
868 EXT4_I(inode)->i_file_acl);
869 goto cleanup;
870
871 #undef header
872 }
873
874 struct ext4_xattr_ibody_find {
875 struct ext4_xattr_search s;
876 struct ext4_iloc iloc;
877 };
878
879 static int
880 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
881 struct ext4_xattr_ibody_find *is)
882 {
883 struct ext4_xattr_ibody_header *header;
884 struct ext4_inode *raw_inode;
885 int error;
886
887 if (EXT4_I(inode)->i_extra_isize == 0)
888 return 0;
889 raw_inode = ext4_raw_inode(&is->iloc);
890 header = IHDR(inode, raw_inode);
891 is->s.base = is->s.first = IFIRST(header);
892 is->s.here = is->s.first;
893 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
894 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
895 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
896 if (error)
897 return error;
898 /* Find the named attribute. */
899 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
900 i->name, is->s.end -
901 (void *)is->s.base, 0);
902 if (error && error != -ENODATA)
903 return error;
904 is->s.not_found = error;
905 }
906 return 0;
907 }
908
909 static int
910 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
911 struct ext4_xattr_info *i,
912 struct ext4_xattr_ibody_find *is)
913 {
914 struct ext4_xattr_ibody_header *header;
915 struct ext4_xattr_search *s = &is->s;
916 int error;
917
918 if (EXT4_I(inode)->i_extra_isize == 0)
919 return -ENOSPC;
920 error = ext4_xattr_set_entry(i, s);
921 if (error)
922 return error;
923 header = IHDR(inode, ext4_raw_inode(&is->iloc));
924 if (!IS_LAST_ENTRY(s->first)) {
925 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
926 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
927 } else {
928 header->h_magic = cpu_to_le32(0);
929 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
930 }
931 return 0;
932 }
933
934 /*
935 * ext4_xattr_set_handle()
936 *
937 * Create, replace or remove an extended attribute for this inode. Buffer
938 * is NULL to remove an existing extended attribute, and non-NULL to
939 * either replace an existing extended attribute, or create a new extended
940 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
941 * specify that an extended attribute must exist and must not exist
942 * previous to the call, respectively.
943 *
944 * Returns 0, or a negative error number on failure.
945 */
946 int
947 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
948 const char *name, const void *value, size_t value_len,
949 int flags)
950 {
951 struct ext4_xattr_info i = {
952 .name_index = name_index,
953 .name = name,
954 .value = value,
955 .value_len = value_len,
956
957 };
958 struct ext4_xattr_ibody_find is = {
959 .s = { .not_found = -ENODATA, },
960 };
961 struct ext4_xattr_block_find bs = {
962 .s = { .not_found = -ENODATA, },
963 };
964 int error;
965
966 if (!name)
967 return -EINVAL;
968 if (strlen(name) > 255)
969 return -ERANGE;
970 down_write(&EXT4_I(inode)->xattr_sem);
971 error = ext4_get_inode_loc(inode, &is.iloc);
972 if (error)
973 goto cleanup;
974
975 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
976 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
977 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
978 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
979 }
980
981 error = ext4_xattr_ibody_find(inode, &i, &is);
982 if (error)
983 goto cleanup;
984 if (is.s.not_found)
985 error = ext4_xattr_block_find(inode, &i, &bs);
986 if (error)
987 goto cleanup;
988 if (is.s.not_found && bs.s.not_found) {
989 error = -ENODATA;
990 if (flags & XATTR_REPLACE)
991 goto cleanup;
992 error = 0;
993 if (!value)
994 goto cleanup;
995 } else {
996 error = -EEXIST;
997 if (flags & XATTR_CREATE)
998 goto cleanup;
999 }
1000 error = ext4_journal_get_write_access(handle, is.iloc.bh);
1001 if (error)
1002 goto cleanup;
1003 if (!value) {
1004 if (!is.s.not_found)
1005 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1006 else if (!bs.s.not_found)
1007 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1008 } else {
1009 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1010 if (!error && !bs.s.not_found) {
1011 i.value = NULL;
1012 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1013 } else if (error == -ENOSPC) {
1014 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1015 if (error)
1016 goto cleanup;
1017 if (!is.s.not_found) {
1018 i.value = NULL;
1019 error = ext4_xattr_ibody_set(handle, inode, &i,
1020 &is);
1021 }
1022 }
1023 }
1024 if (!error) {
1025 ext4_xattr_update_super_block(handle, inode->i_sb);
1026 inode->i_ctime = ext4_current_time(inode);
1027 if (!value)
1028 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1029 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1030 /*
1031 * The bh is consumed by ext4_mark_iloc_dirty, even with
1032 * error != 0.
1033 */
1034 is.iloc.bh = NULL;
1035 if (IS_SYNC(inode))
1036 handle->h_sync = 1;
1037 }
1038
1039 cleanup:
1040 brelse(is.iloc.bh);
1041 brelse(bs.bh);
1042 up_write(&EXT4_I(inode)->xattr_sem);
1043 return error;
1044 }
1045
1046 /*
1047 * ext4_xattr_set()
1048 *
1049 * Like ext4_xattr_set_handle, but start from an inode. This extended
1050 * attribute modification is a filesystem transaction by itself.
1051 *
1052 * Returns 0, or a negative error number on failure.
1053 */
1054 int
1055 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1056 const void *value, size_t value_len, int flags)
1057 {
1058 handle_t *handle;
1059 int error, retries = 0;
1060
1061 retry:
1062 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1063 if (IS_ERR(handle)) {
1064 error = PTR_ERR(handle);
1065 } else {
1066 int error2;
1067
1068 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1069 value, value_len, flags);
1070 error2 = ext4_journal_stop(handle);
1071 if (error == -ENOSPC &&
1072 ext4_should_retry_alloc(inode->i_sb, &retries))
1073 goto retry;
1074 if (error == 0)
1075 error = error2;
1076 }
1077
1078 return error;
1079 }
1080
1081 /*
1082 * Shift the EA entries in the inode to create space for the increased
1083 * i_extra_isize.
1084 */
1085 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1086 int value_offs_shift, void *to,
1087 void *from, size_t n, int blocksize)
1088 {
1089 struct ext4_xattr_entry *last = entry;
1090 int new_offs;
1091
1092 /* Adjust the value offsets of the entries */
1093 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1094 if (!last->e_value_block && last->e_value_size) {
1095 new_offs = le16_to_cpu(last->e_value_offs) +
1096 value_offs_shift;
1097 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1098 > blocksize);
1099 last->e_value_offs = cpu_to_le16(new_offs);
1100 }
1101 }
1102 /* Shift the entries by n bytes */
1103 memmove(to, from, n);
1104 }
1105
1106 /*
1107 * Expand an inode by new_extra_isize bytes when EAs are present.
1108 * Returns 0 on success or negative error number on failure.
1109 */
1110 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1111 struct ext4_inode *raw_inode, handle_t *handle)
1112 {
1113 struct ext4_xattr_ibody_header *header;
1114 struct ext4_xattr_entry *entry, *last, *first;
1115 struct buffer_head *bh = NULL;
1116 struct ext4_xattr_ibody_find *is = NULL;
1117 struct ext4_xattr_block_find *bs = NULL;
1118 char *buffer = NULL, *b_entry_name = NULL;
1119 size_t min_offs, free;
1120 int total_ino, total_blk;
1121 void *base, *start, *end;
1122 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1123 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1124
1125 down_write(&EXT4_I(inode)->xattr_sem);
1126 retry:
1127 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1128 up_write(&EXT4_I(inode)->xattr_sem);
1129 return 0;
1130 }
1131
1132 header = IHDR(inode, raw_inode);
1133 entry = IFIRST(header);
1134
1135 /*
1136 * Check if enough free space is available in the inode to shift the
1137 * entries ahead by new_extra_isize.
1138 */
1139
1140 base = start = entry;
1141 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1142 min_offs = end - base;
1143 last = entry;
1144 total_ino = sizeof(struct ext4_xattr_ibody_header);
1145
1146 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1147 if (free >= new_extra_isize) {
1148 entry = IFIRST(header);
1149 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1150 - new_extra_isize, (void *)raw_inode +
1151 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1152 (void *)header, total_ino,
1153 inode->i_sb->s_blocksize);
1154 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1155 error = 0;
1156 goto cleanup;
1157 }
1158
1159 /*
1160 * Enough free space isn't available in the inode, check if
1161 * EA block can hold new_extra_isize bytes.
1162 */
1163 if (EXT4_I(inode)->i_file_acl) {
1164 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1165 error = -EIO;
1166 if (!bh)
1167 goto cleanup;
1168 if (ext4_xattr_check_block(bh)) {
1169 ext4_error(inode->i_sb, __FUNCTION__,
1170 "inode %lu: bad block %llu", inode->i_ino,
1171 EXT4_I(inode)->i_file_acl);
1172 error = -EIO;
1173 goto cleanup;
1174 }
1175 base = BHDR(bh);
1176 first = BFIRST(bh);
1177 end = bh->b_data + bh->b_size;
1178 min_offs = end - base;
1179 free = ext4_xattr_free_space(first, &min_offs, base,
1180 &total_blk);
1181 if (free < new_extra_isize) {
1182 if (!tried_min_extra_isize && s_min_extra_isize) {
1183 tried_min_extra_isize++;
1184 new_extra_isize = s_min_extra_isize;
1185 brelse(bh);
1186 goto retry;
1187 }
1188 error = -1;
1189 goto cleanup;
1190 }
1191 } else {
1192 free = inode->i_sb->s_blocksize;
1193 }
1194
1195 while (new_extra_isize > 0) {
1196 size_t offs, size, entry_size;
1197 struct ext4_xattr_entry *small_entry = NULL;
1198 struct ext4_xattr_info i = {
1199 .value = NULL,
1200 .value_len = 0,
1201 };
1202 unsigned int total_size; /* EA entry size + value size */
1203 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1204 unsigned int min_total_size = ~0U;
1205
1206 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1207 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1208 if (!is || !bs) {
1209 error = -ENOMEM;
1210 goto cleanup;
1211 }
1212
1213 is->s.not_found = -ENODATA;
1214 bs->s.not_found = -ENODATA;
1215 is->iloc.bh = NULL;
1216 bs->bh = NULL;
1217
1218 last = IFIRST(header);
1219 /* Find the entry best suited to be pushed into EA block */
1220 entry = NULL;
1221 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1222 total_size =
1223 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1224 EXT4_XATTR_LEN(last->e_name_len);
1225 if (total_size <= free && total_size < min_total_size) {
1226 if (total_size < new_extra_isize) {
1227 small_entry = last;
1228 } else {
1229 entry = last;
1230 min_total_size = total_size;
1231 }
1232 }
1233 }
1234
1235 if (entry == NULL) {
1236 if (small_entry) {
1237 entry = small_entry;
1238 } else {
1239 if (!tried_min_extra_isize &&
1240 s_min_extra_isize) {
1241 tried_min_extra_isize++;
1242 new_extra_isize = s_min_extra_isize;
1243 goto retry;
1244 }
1245 error = -1;
1246 goto cleanup;
1247 }
1248 }
1249 offs = le16_to_cpu(entry->e_value_offs);
1250 size = le32_to_cpu(entry->e_value_size);
1251 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1252 i.name_index = entry->e_name_index,
1253 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1254 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1255 if (!buffer || !b_entry_name) {
1256 error = -ENOMEM;
1257 goto cleanup;
1258 }
1259 /* Save the entry name and the entry value */
1260 memcpy(buffer, (void *)IFIRST(header) + offs,
1261 EXT4_XATTR_SIZE(size));
1262 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1263 b_entry_name[entry->e_name_len] = '\0';
1264 i.name = b_entry_name;
1265
1266 error = ext4_get_inode_loc(inode, &is->iloc);
1267 if (error)
1268 goto cleanup;
1269
1270 error = ext4_xattr_ibody_find(inode, &i, is);
1271 if (error)
1272 goto cleanup;
1273
1274 /* Remove the chosen entry from the inode */
1275 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1276
1277 entry = IFIRST(header);
1278 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1279 shift_bytes = new_extra_isize;
1280 else
1281 shift_bytes = entry_size + size;
1282 /* Adjust the offsets and shift the remaining entries ahead */
1283 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1284 shift_bytes, (void *)raw_inode +
1285 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1286 (void *)header, total_ino - entry_size,
1287 inode->i_sb->s_blocksize);
1288
1289 extra_isize += shift_bytes;
1290 new_extra_isize -= shift_bytes;
1291 EXT4_I(inode)->i_extra_isize = extra_isize;
1292
1293 i.name = b_entry_name;
1294 i.value = buffer;
1295 i.value_len = size;
1296 error = ext4_xattr_block_find(inode, &i, bs);
1297 if (error)
1298 goto cleanup;
1299
1300 /* Add entry which was removed from the inode into the block */
1301 error = ext4_xattr_block_set(handle, inode, &i, bs);
1302 if (error)
1303 goto cleanup;
1304 kfree(b_entry_name);
1305 kfree(buffer);
1306 brelse(is->iloc.bh);
1307 kfree(is);
1308 kfree(bs);
1309 }
1310 brelse(bh);
1311 up_write(&EXT4_I(inode)->xattr_sem);
1312 return 0;
1313
1314 cleanup:
1315 kfree(b_entry_name);
1316 kfree(buffer);
1317 if (is)
1318 brelse(is->iloc.bh);
1319 kfree(is);
1320 kfree(bs);
1321 brelse(bh);
1322 up_write(&EXT4_I(inode)->xattr_sem);
1323 return error;
1324 }
1325
1326
1327
1328 /*
1329 * ext4_xattr_delete_inode()
1330 *
1331 * Free extended attribute resources associated with this inode. This
1332 * is called immediately before an inode is freed. We have exclusive
1333 * access to the inode.
1334 */
1335 void
1336 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1337 {
1338 struct buffer_head *bh = NULL;
1339
1340 if (!EXT4_I(inode)->i_file_acl)
1341 goto cleanup;
1342 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1343 if (!bh) {
1344 ext4_error(inode->i_sb, __FUNCTION__,
1345 "inode %lu: block %llu read error", inode->i_ino,
1346 EXT4_I(inode)->i_file_acl);
1347 goto cleanup;
1348 }
1349 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1350 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1351 ext4_error(inode->i_sb, __FUNCTION__,
1352 "inode %lu: bad block %llu", inode->i_ino,
1353 EXT4_I(inode)->i_file_acl);
1354 goto cleanup;
1355 }
1356 ext4_xattr_release_block(handle, inode, bh);
1357 EXT4_I(inode)->i_file_acl = 0;
1358
1359 cleanup:
1360 brelse(bh);
1361 }
1362
1363 /*
1364 * ext4_xattr_put_super()
1365 *
1366 * This is called when a file system is unmounted.
1367 */
1368 void
1369 ext4_xattr_put_super(struct super_block *sb)
1370 {
1371 mb_cache_shrink(sb->s_bdev);
1372 }
1373
1374 /*
1375 * ext4_xattr_cache_insert()
1376 *
1377 * Create a new entry in the extended attribute cache, and insert
1378 * it unless such an entry is already in the cache.
1379 *
1380 * Returns 0, or a negative error number on failure.
1381 */
1382 static void
1383 ext4_xattr_cache_insert(struct buffer_head *bh)
1384 {
1385 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1386 struct mb_cache_entry *ce;
1387 int error;
1388
1389 ce = mb_cache_entry_alloc(ext4_xattr_cache);
1390 if (!ce) {
1391 ea_bdebug(bh, "out of memory");
1392 return;
1393 }
1394 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1395 if (error) {
1396 mb_cache_entry_free(ce);
1397 if (error == -EBUSY) {
1398 ea_bdebug(bh, "already in cache");
1399 error = 0;
1400 }
1401 } else {
1402 ea_bdebug(bh, "inserting [%x]", (int)hash);
1403 mb_cache_entry_release(ce);
1404 }
1405 }
1406
1407 /*
1408 * ext4_xattr_cmp()
1409 *
1410 * Compare two extended attribute blocks for equality.
1411 *
1412 * Returns 0 if the blocks are equal, 1 if they differ, and
1413 * a negative error number on errors.
1414 */
1415 static int
1416 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1417 struct ext4_xattr_header *header2)
1418 {
1419 struct ext4_xattr_entry *entry1, *entry2;
1420
1421 entry1 = ENTRY(header1+1);
1422 entry2 = ENTRY(header2+1);
1423 while (!IS_LAST_ENTRY(entry1)) {
1424 if (IS_LAST_ENTRY(entry2))
1425 return 1;
1426 if (entry1->e_hash != entry2->e_hash ||
1427 entry1->e_name_index != entry2->e_name_index ||
1428 entry1->e_name_len != entry2->e_name_len ||
1429 entry1->e_value_size != entry2->e_value_size ||
1430 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1431 return 1;
1432 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1433 return -EIO;
1434 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1435 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1436 le32_to_cpu(entry1->e_value_size)))
1437 return 1;
1438
1439 entry1 = EXT4_XATTR_NEXT(entry1);
1440 entry2 = EXT4_XATTR_NEXT(entry2);
1441 }
1442 if (!IS_LAST_ENTRY(entry2))
1443 return 1;
1444 return 0;
1445 }
1446
1447 /*
1448 * ext4_xattr_cache_find()
1449 *
1450 * Find an identical extended attribute block.
1451 *
1452 * Returns a pointer to the block found, or NULL if such a block was
1453 * not found or an error occurred.
1454 */
1455 static struct buffer_head *
1456 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1457 struct mb_cache_entry **pce)
1458 {
1459 __u32 hash = le32_to_cpu(header->h_hash);
1460 struct mb_cache_entry *ce;
1461
1462 if (!header->h_hash)
1463 return NULL; /* never share */
1464 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1465 again:
1466 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1467 inode->i_sb->s_bdev, hash);
1468 while (ce) {
1469 struct buffer_head *bh;
1470
1471 if (IS_ERR(ce)) {
1472 if (PTR_ERR(ce) == -EAGAIN)
1473 goto again;
1474 break;
1475 }
1476 bh = sb_bread(inode->i_sb, ce->e_block);
1477 if (!bh) {
1478 ext4_error(inode->i_sb, __FUNCTION__,
1479 "inode %lu: block %lu read error",
1480 inode->i_ino, (unsigned long) ce->e_block);
1481 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1482 EXT4_XATTR_REFCOUNT_MAX) {
1483 ea_idebug(inode, "block %lu refcount %d>=%d",
1484 (unsigned long) ce->e_block,
1485 le32_to_cpu(BHDR(bh)->h_refcount),
1486 EXT4_XATTR_REFCOUNT_MAX);
1487 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1488 *pce = ce;
1489 return bh;
1490 }
1491 brelse(bh);
1492 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1493 }
1494 return NULL;
1495 }
1496
1497 #define NAME_HASH_SHIFT 5
1498 #define VALUE_HASH_SHIFT 16
1499
1500 /*
1501 * ext4_xattr_hash_entry()
1502 *
1503 * Compute the hash of an extended attribute.
1504 */
1505 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1506 struct ext4_xattr_entry *entry)
1507 {
1508 __u32 hash = 0;
1509 char *name = entry->e_name;
1510 int n;
1511
1512 for (n=0; n < entry->e_name_len; n++) {
1513 hash = (hash << NAME_HASH_SHIFT) ^
1514 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1515 *name++;
1516 }
1517
1518 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1519 __le32 *value = (__le32 *)((char *)header +
1520 le16_to_cpu(entry->e_value_offs));
1521 for (n = (le32_to_cpu(entry->e_value_size) +
1522 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1523 hash = (hash << VALUE_HASH_SHIFT) ^
1524 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1525 le32_to_cpu(*value++);
1526 }
1527 }
1528 entry->e_hash = cpu_to_le32(hash);
1529 }
1530
1531 #undef NAME_HASH_SHIFT
1532 #undef VALUE_HASH_SHIFT
1533
1534 #define BLOCK_HASH_SHIFT 16
1535
1536 /*
1537 * ext4_xattr_rehash()
1538 *
1539 * Re-compute the extended attribute hash value after an entry has changed.
1540 */
1541 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1542 struct ext4_xattr_entry *entry)
1543 {
1544 struct ext4_xattr_entry *here;
1545 __u32 hash = 0;
1546
1547 ext4_xattr_hash_entry(header, entry);
1548 here = ENTRY(header+1);
1549 while (!IS_LAST_ENTRY(here)) {
1550 if (!here->e_hash) {
1551 /* Block is not shared if an entry's hash value == 0 */
1552 hash = 0;
1553 break;
1554 }
1555 hash = (hash << BLOCK_HASH_SHIFT) ^
1556 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1557 le32_to_cpu(here->e_hash);
1558 here = EXT4_XATTR_NEXT(here);
1559 }
1560 header->h_hash = cpu_to_le32(hash);
1561 }
1562
1563 #undef BLOCK_HASH_SHIFT
1564
1565 int __init
1566 init_ext4_xattr(void)
1567 {
1568 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1569 sizeof(struct mb_cache_entry) +
1570 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1571 if (!ext4_xattr_cache)
1572 return -ENOMEM;
1573 return 0;
1574 }
1575
1576 void
1577 exit_ext4_xattr(void)
1578 {
1579 if (ext4_xattr_cache)
1580 mb_cache_destroy(ext4_xattr_cache);
1581 ext4_xattr_cache = NULL;
1582 }
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