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Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd
[mirror_ubuntu-artful-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/mbcache.h>
57 #include <linux/quotaops.h>
58 #include <linux/rwsem.h>
59 #include "ext4_jbd2.h"
60 #include "ext4.h"
61 #include "xattr.h"
62 #include "acl.h"
63
64 #ifdef EXT4_XATTR_DEBUG
65 # define ea_idebug(inode, f...) do { \
66 printk(KERN_DEBUG "inode %s:%lu: ", \
67 inode->i_sb->s_id, inode->i_ino); \
68 printk(f); \
69 printk("\n"); \
70 } while (0)
71 # define ea_bdebug(bh, f...) do { \
72 char b[BDEVNAME_SIZE]; \
73 printk(KERN_DEBUG "block %s:%lu: ", \
74 bdevname(bh->b_bdev, b), \
75 (unsigned long) bh->b_blocknr); \
76 printk(f); \
77 printk("\n"); \
78 } while (0)
79 #else
80 # define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
81 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
82 #endif
83
84 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
85 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
86 struct ext4_xattr_header *,
87 struct mb_cache_entry **);
88 static void ext4_xattr_rehash(struct ext4_xattr_header *,
89 struct ext4_xattr_entry *);
90 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
91 size_t buffer_size);
92
93 static const struct xattr_handler *ext4_xattr_handler_map[] = {
94 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
95 #ifdef CONFIG_EXT4_FS_POSIX_ACL
96 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
97 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
98 #endif
99 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
100 #ifdef CONFIG_EXT4_FS_SECURITY
101 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
102 #endif
103 };
104
105 const struct xattr_handler *ext4_xattr_handlers[] = {
106 &ext4_xattr_user_handler,
107 &ext4_xattr_trusted_handler,
108 #ifdef CONFIG_EXT4_FS_POSIX_ACL
109 &posix_acl_access_xattr_handler,
110 &posix_acl_default_xattr_handler,
111 #endif
112 #ifdef CONFIG_EXT4_FS_SECURITY
113 &ext4_xattr_security_handler,
114 #endif
115 NULL
116 };
117
118 #define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \
119 inode->i_sb->s_fs_info)->s_mb_cache)
120
121 static __le32 ext4_xattr_block_csum(struct inode *inode,
122 sector_t block_nr,
123 struct ext4_xattr_header *hdr)
124 {
125 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
126 __u32 csum;
127 __le32 save_csum;
128 __le64 dsk_block_nr = cpu_to_le64(block_nr);
129
130 save_csum = hdr->h_checksum;
131 hdr->h_checksum = 0;
132 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
133 sizeof(dsk_block_nr));
134 csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
135 EXT4_BLOCK_SIZE(inode->i_sb));
136
137 hdr->h_checksum = save_csum;
138 return cpu_to_le32(csum);
139 }
140
141 static int ext4_xattr_block_csum_verify(struct inode *inode,
142 sector_t block_nr,
143 struct ext4_xattr_header *hdr)
144 {
145 if (ext4_has_metadata_csum(inode->i_sb) &&
146 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
147 return 0;
148 return 1;
149 }
150
151 static void ext4_xattr_block_csum_set(struct inode *inode,
152 sector_t block_nr,
153 struct ext4_xattr_header *hdr)
154 {
155 if (!ext4_has_metadata_csum(inode->i_sb))
156 return;
157
158 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
159 }
160
161 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
162 struct inode *inode,
163 struct buffer_head *bh)
164 {
165 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
166 return ext4_handle_dirty_metadata(handle, inode, bh);
167 }
168
169 static inline const struct xattr_handler *
170 ext4_xattr_handler(int name_index)
171 {
172 const struct xattr_handler *handler = NULL;
173
174 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
175 handler = ext4_xattr_handler_map[name_index];
176 return handler;
177 }
178
179 /*
180 * Inode operation listxattr()
181 *
182 * dentry->d_inode->i_mutex: don't care
183 */
184 ssize_t
185 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
186 {
187 return ext4_xattr_list(dentry, buffer, size);
188 }
189
190 static int
191 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
192 void *value_start)
193 {
194 struct ext4_xattr_entry *e = entry;
195
196 while (!IS_LAST_ENTRY(e)) {
197 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
198 if ((void *)next >= end)
199 return -EIO;
200 e = next;
201 }
202
203 while (!IS_LAST_ENTRY(entry)) {
204 if (entry->e_value_size != 0 &&
205 (value_start + le16_to_cpu(entry->e_value_offs) <
206 (void *)e + sizeof(__u32) ||
207 value_start + le16_to_cpu(entry->e_value_offs) +
208 le32_to_cpu(entry->e_value_size) > end))
209 return -EIO;
210 entry = EXT4_XATTR_NEXT(entry);
211 }
212
213 return 0;
214 }
215
216 static inline int
217 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
218 {
219 int error;
220
221 if (buffer_verified(bh))
222 return 0;
223
224 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
225 BHDR(bh)->h_blocks != cpu_to_le32(1))
226 return -EIO;
227 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
228 return -EIO;
229 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
230 bh->b_data);
231 if (!error)
232 set_buffer_verified(bh);
233 return error;
234 }
235
236 static inline int
237 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
238 {
239 size_t value_size = le32_to_cpu(entry->e_value_size);
240
241 if (entry->e_value_block != 0 || value_size > size ||
242 le16_to_cpu(entry->e_value_offs) + value_size > size)
243 return -EIO;
244 return 0;
245 }
246
247 static int
248 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
249 const char *name, size_t size, int sorted)
250 {
251 struct ext4_xattr_entry *entry;
252 size_t name_len;
253 int cmp = 1;
254
255 if (name == NULL)
256 return -EINVAL;
257 name_len = strlen(name);
258 entry = *pentry;
259 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
260 cmp = name_index - entry->e_name_index;
261 if (!cmp)
262 cmp = name_len - entry->e_name_len;
263 if (!cmp)
264 cmp = memcmp(name, entry->e_name, name_len);
265 if (cmp <= 0 && (sorted || cmp == 0))
266 break;
267 }
268 *pentry = entry;
269 if (!cmp && ext4_xattr_check_entry(entry, size))
270 return -EIO;
271 return cmp ? -ENODATA : 0;
272 }
273
274 static int
275 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
276 void *buffer, size_t buffer_size)
277 {
278 struct buffer_head *bh = NULL;
279 struct ext4_xattr_entry *entry;
280 size_t size;
281 int error;
282 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
283
284 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
285 name_index, name, buffer, (long)buffer_size);
286
287 error = -ENODATA;
288 if (!EXT4_I(inode)->i_file_acl)
289 goto cleanup;
290 ea_idebug(inode, "reading block %llu",
291 (unsigned long long)EXT4_I(inode)->i_file_acl);
292 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
293 if (!bh)
294 goto cleanup;
295 ea_bdebug(bh, "b_count=%d, refcount=%d",
296 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
297 if (ext4_xattr_check_block(inode, bh)) {
298 bad_block:
299 EXT4_ERROR_INODE(inode, "bad block %llu",
300 EXT4_I(inode)->i_file_acl);
301 error = -EIO;
302 goto cleanup;
303 }
304 ext4_xattr_cache_insert(ext4_mb_cache, bh);
305 entry = BFIRST(bh);
306 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
307 if (error == -EIO)
308 goto bad_block;
309 if (error)
310 goto cleanup;
311 size = le32_to_cpu(entry->e_value_size);
312 if (buffer) {
313 error = -ERANGE;
314 if (size > buffer_size)
315 goto cleanup;
316 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
317 size);
318 }
319 error = size;
320
321 cleanup:
322 brelse(bh);
323 return error;
324 }
325
326 int
327 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
328 void *buffer, size_t buffer_size)
329 {
330 struct ext4_xattr_ibody_header *header;
331 struct ext4_xattr_entry *entry;
332 struct ext4_inode *raw_inode;
333 struct ext4_iloc iloc;
334 size_t size;
335 void *end;
336 int error;
337
338 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
339 return -ENODATA;
340 error = ext4_get_inode_loc(inode, &iloc);
341 if (error)
342 return error;
343 raw_inode = ext4_raw_inode(&iloc);
344 header = IHDR(inode, raw_inode);
345 entry = IFIRST(header);
346 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
347 error = ext4_xattr_check_names(entry, end, entry);
348 if (error)
349 goto cleanup;
350 error = ext4_xattr_find_entry(&entry, name_index, name,
351 end - (void *)entry, 0);
352 if (error)
353 goto cleanup;
354 size = le32_to_cpu(entry->e_value_size);
355 if (buffer) {
356 error = -ERANGE;
357 if (size > buffer_size)
358 goto cleanup;
359 memcpy(buffer, (void *)IFIRST(header) +
360 le16_to_cpu(entry->e_value_offs), size);
361 }
362 error = size;
363
364 cleanup:
365 brelse(iloc.bh);
366 return error;
367 }
368
369 /*
370 * ext4_xattr_get()
371 *
372 * Copy an extended attribute into the buffer
373 * provided, or compute the buffer size required.
374 * Buffer is NULL to compute the size of the buffer required.
375 *
376 * Returns a negative error number on failure, or the number of bytes
377 * used / required on success.
378 */
379 int
380 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
381 void *buffer, size_t buffer_size)
382 {
383 int error;
384
385 if (strlen(name) > 255)
386 return -ERANGE;
387
388 down_read(&EXT4_I(inode)->xattr_sem);
389 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
390 buffer_size);
391 if (error == -ENODATA)
392 error = ext4_xattr_block_get(inode, name_index, name, buffer,
393 buffer_size);
394 up_read(&EXT4_I(inode)->xattr_sem);
395 return error;
396 }
397
398 static int
399 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
400 char *buffer, size_t buffer_size)
401 {
402 size_t rest = buffer_size;
403
404 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
405 const struct xattr_handler *handler =
406 ext4_xattr_handler(entry->e_name_index);
407
408 if (handler) {
409 size_t size = handler->list(dentry, buffer, rest,
410 entry->e_name,
411 entry->e_name_len,
412 handler->flags);
413 if (buffer) {
414 if (size > rest)
415 return -ERANGE;
416 buffer += size;
417 }
418 rest -= size;
419 }
420 }
421 return buffer_size - rest;
422 }
423
424 static int
425 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
426 {
427 struct inode *inode = dentry->d_inode;
428 struct buffer_head *bh = NULL;
429 int error;
430 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
431
432 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
433 buffer, (long)buffer_size);
434
435 error = 0;
436 if (!EXT4_I(inode)->i_file_acl)
437 goto cleanup;
438 ea_idebug(inode, "reading block %llu",
439 (unsigned long long)EXT4_I(inode)->i_file_acl);
440 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
441 error = -EIO;
442 if (!bh)
443 goto cleanup;
444 ea_bdebug(bh, "b_count=%d, refcount=%d",
445 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
446 if (ext4_xattr_check_block(inode, bh)) {
447 EXT4_ERROR_INODE(inode, "bad block %llu",
448 EXT4_I(inode)->i_file_acl);
449 error = -EIO;
450 goto cleanup;
451 }
452 ext4_xattr_cache_insert(ext4_mb_cache, bh);
453 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
454
455 cleanup:
456 brelse(bh);
457
458 return error;
459 }
460
461 static int
462 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
463 {
464 struct inode *inode = dentry->d_inode;
465 struct ext4_xattr_ibody_header *header;
466 struct ext4_inode *raw_inode;
467 struct ext4_iloc iloc;
468 void *end;
469 int error;
470
471 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
472 return 0;
473 error = ext4_get_inode_loc(inode, &iloc);
474 if (error)
475 return error;
476 raw_inode = ext4_raw_inode(&iloc);
477 header = IHDR(inode, raw_inode);
478 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
479 error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header));
480 if (error)
481 goto cleanup;
482 error = ext4_xattr_list_entries(dentry, IFIRST(header),
483 buffer, buffer_size);
484
485 cleanup:
486 brelse(iloc.bh);
487 return error;
488 }
489
490 /*
491 * ext4_xattr_list()
492 *
493 * Copy a list of attribute names into the buffer
494 * provided, or compute the buffer size required.
495 * Buffer is NULL to compute the size of the buffer required.
496 *
497 * Returns a negative error number on failure, or the number of bytes
498 * used / required on success.
499 */
500 static int
501 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
502 {
503 int ret, ret2;
504
505 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
506 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
507 if (ret < 0)
508 goto errout;
509 if (buffer) {
510 buffer += ret;
511 buffer_size -= ret;
512 }
513 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
514 if (ret < 0)
515 goto errout;
516 ret += ret2;
517 errout:
518 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
519 return ret;
520 }
521
522 /*
523 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
524 * not set, set it.
525 */
526 static void ext4_xattr_update_super_block(handle_t *handle,
527 struct super_block *sb)
528 {
529 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
530 return;
531
532 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
533 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
534 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
535 ext4_handle_dirty_super(handle, sb);
536 }
537 }
538
539 /*
540 * Release the xattr block BH: If the reference count is > 1, decrement it;
541 * otherwise free the block.
542 */
543 static void
544 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
545 struct buffer_head *bh)
546 {
547 struct mb_cache_entry *ce = NULL;
548 int error = 0;
549 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
550
551 ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr);
552 BUFFER_TRACE(bh, "get_write_access");
553 error = ext4_journal_get_write_access(handle, bh);
554 if (error)
555 goto out;
556
557 lock_buffer(bh);
558 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
559 ea_bdebug(bh, "refcount now=0; freeing");
560 if (ce)
561 mb_cache_entry_free(ce);
562 get_bh(bh);
563 unlock_buffer(bh);
564 ext4_free_blocks(handle, inode, bh, 0, 1,
565 EXT4_FREE_BLOCKS_METADATA |
566 EXT4_FREE_BLOCKS_FORGET);
567 } else {
568 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
569 if (ce)
570 mb_cache_entry_release(ce);
571 /*
572 * Beware of this ugliness: Releasing of xattr block references
573 * from different inodes can race and so we have to protect
574 * from a race where someone else frees the block (and releases
575 * its journal_head) before we are done dirtying the buffer. In
576 * nojournal mode this race is harmless and we actually cannot
577 * call ext4_handle_dirty_xattr_block() with locked buffer as
578 * that function can call sync_dirty_buffer() so for that case
579 * we handle the dirtying after unlocking the buffer.
580 */
581 if (ext4_handle_valid(handle))
582 error = ext4_handle_dirty_xattr_block(handle, inode,
583 bh);
584 unlock_buffer(bh);
585 if (!ext4_handle_valid(handle))
586 error = ext4_handle_dirty_xattr_block(handle, inode,
587 bh);
588 if (IS_SYNC(inode))
589 ext4_handle_sync(handle);
590 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
591 ea_bdebug(bh, "refcount now=%d; releasing",
592 le32_to_cpu(BHDR(bh)->h_refcount));
593 }
594 out:
595 ext4_std_error(inode->i_sb, error);
596 return;
597 }
598
599 /*
600 * Find the available free space for EAs. This also returns the total number of
601 * bytes used by EA entries.
602 */
603 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
604 size_t *min_offs, void *base, int *total)
605 {
606 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
607 if (!last->e_value_block && last->e_value_size) {
608 size_t offs = le16_to_cpu(last->e_value_offs);
609 if (offs < *min_offs)
610 *min_offs = offs;
611 }
612 if (total)
613 *total += EXT4_XATTR_LEN(last->e_name_len);
614 }
615 return (*min_offs - ((void *)last - base) - sizeof(__u32));
616 }
617
618 static int
619 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
620 {
621 struct ext4_xattr_entry *last;
622 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
623
624 /* Compute min_offs and last. */
625 last = s->first;
626 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
627 if (!last->e_value_block && last->e_value_size) {
628 size_t offs = le16_to_cpu(last->e_value_offs);
629 if (offs < min_offs)
630 min_offs = offs;
631 }
632 }
633 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
634 if (!s->not_found) {
635 if (!s->here->e_value_block && s->here->e_value_size) {
636 size_t size = le32_to_cpu(s->here->e_value_size);
637 free += EXT4_XATTR_SIZE(size);
638 }
639 free += EXT4_XATTR_LEN(name_len);
640 }
641 if (i->value) {
642 if (free < EXT4_XATTR_SIZE(i->value_len) ||
643 free < EXT4_XATTR_LEN(name_len) +
644 EXT4_XATTR_SIZE(i->value_len))
645 return -ENOSPC;
646 }
647
648 if (i->value && s->not_found) {
649 /* Insert the new name. */
650 size_t size = EXT4_XATTR_LEN(name_len);
651 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
652 memmove((void *)s->here + size, s->here, rest);
653 memset(s->here, 0, size);
654 s->here->e_name_index = i->name_index;
655 s->here->e_name_len = name_len;
656 memcpy(s->here->e_name, i->name, name_len);
657 } else {
658 if (!s->here->e_value_block && s->here->e_value_size) {
659 void *first_val = s->base + min_offs;
660 size_t offs = le16_to_cpu(s->here->e_value_offs);
661 void *val = s->base + offs;
662 size_t size = EXT4_XATTR_SIZE(
663 le32_to_cpu(s->here->e_value_size));
664
665 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
666 /* The old and the new value have the same
667 size. Just replace. */
668 s->here->e_value_size =
669 cpu_to_le32(i->value_len);
670 if (i->value == EXT4_ZERO_XATTR_VALUE) {
671 memset(val, 0, size);
672 } else {
673 /* Clear pad bytes first. */
674 memset(val + size - EXT4_XATTR_PAD, 0,
675 EXT4_XATTR_PAD);
676 memcpy(val, i->value, i->value_len);
677 }
678 return 0;
679 }
680
681 /* Remove the old value. */
682 memmove(first_val + size, first_val, val - first_val);
683 memset(first_val, 0, size);
684 s->here->e_value_size = 0;
685 s->here->e_value_offs = 0;
686 min_offs += size;
687
688 /* Adjust all value offsets. */
689 last = s->first;
690 while (!IS_LAST_ENTRY(last)) {
691 size_t o = le16_to_cpu(last->e_value_offs);
692 if (!last->e_value_block &&
693 last->e_value_size && o < offs)
694 last->e_value_offs =
695 cpu_to_le16(o + size);
696 last = EXT4_XATTR_NEXT(last);
697 }
698 }
699 if (!i->value) {
700 /* Remove the old name. */
701 size_t size = EXT4_XATTR_LEN(name_len);
702 last = ENTRY((void *)last - size);
703 memmove(s->here, (void *)s->here + size,
704 (void *)last - (void *)s->here + sizeof(__u32));
705 memset(last, 0, size);
706 }
707 }
708
709 if (i->value) {
710 /* Insert the new value. */
711 s->here->e_value_size = cpu_to_le32(i->value_len);
712 if (i->value_len) {
713 size_t size = EXT4_XATTR_SIZE(i->value_len);
714 void *val = s->base + min_offs - size;
715 s->here->e_value_offs = cpu_to_le16(min_offs - size);
716 if (i->value == EXT4_ZERO_XATTR_VALUE) {
717 memset(val, 0, size);
718 } else {
719 /* Clear the pad bytes first. */
720 memset(val + size - EXT4_XATTR_PAD, 0,
721 EXT4_XATTR_PAD);
722 memcpy(val, i->value, i->value_len);
723 }
724 }
725 }
726 return 0;
727 }
728
729 struct ext4_xattr_block_find {
730 struct ext4_xattr_search s;
731 struct buffer_head *bh;
732 };
733
734 static int
735 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
736 struct ext4_xattr_block_find *bs)
737 {
738 struct super_block *sb = inode->i_sb;
739 int error;
740
741 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
742 i->name_index, i->name, i->value, (long)i->value_len);
743
744 if (EXT4_I(inode)->i_file_acl) {
745 /* The inode already has an extended attribute block. */
746 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
747 error = -EIO;
748 if (!bs->bh)
749 goto cleanup;
750 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
751 atomic_read(&(bs->bh->b_count)),
752 le32_to_cpu(BHDR(bs->bh)->h_refcount));
753 if (ext4_xattr_check_block(inode, bs->bh)) {
754 EXT4_ERROR_INODE(inode, "bad block %llu",
755 EXT4_I(inode)->i_file_acl);
756 error = -EIO;
757 goto cleanup;
758 }
759 /* Find the named attribute. */
760 bs->s.base = BHDR(bs->bh);
761 bs->s.first = BFIRST(bs->bh);
762 bs->s.end = bs->bh->b_data + bs->bh->b_size;
763 bs->s.here = bs->s.first;
764 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
765 i->name, bs->bh->b_size, 1);
766 if (error && error != -ENODATA)
767 goto cleanup;
768 bs->s.not_found = error;
769 }
770 error = 0;
771
772 cleanup:
773 return error;
774 }
775
776 static int
777 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
778 struct ext4_xattr_info *i,
779 struct ext4_xattr_block_find *bs)
780 {
781 struct super_block *sb = inode->i_sb;
782 struct buffer_head *new_bh = NULL;
783 struct ext4_xattr_search *s = &bs->s;
784 struct mb_cache_entry *ce = NULL;
785 int error = 0;
786 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
787
788 #define header(x) ((struct ext4_xattr_header *)(x))
789
790 if (i->value && i->value_len > sb->s_blocksize)
791 return -ENOSPC;
792 if (s->base) {
793 ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev,
794 bs->bh->b_blocknr);
795 BUFFER_TRACE(bs->bh, "get_write_access");
796 error = ext4_journal_get_write_access(handle, bs->bh);
797 if (error)
798 goto cleanup;
799 lock_buffer(bs->bh);
800
801 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
802 if (ce) {
803 mb_cache_entry_free(ce);
804 ce = NULL;
805 }
806 ea_bdebug(bs->bh, "modifying in-place");
807 error = ext4_xattr_set_entry(i, s);
808 if (!error) {
809 if (!IS_LAST_ENTRY(s->first))
810 ext4_xattr_rehash(header(s->base),
811 s->here);
812 ext4_xattr_cache_insert(ext4_mb_cache,
813 bs->bh);
814 }
815 unlock_buffer(bs->bh);
816 if (error == -EIO)
817 goto bad_block;
818 if (!error)
819 error = ext4_handle_dirty_xattr_block(handle,
820 inode,
821 bs->bh);
822 if (error)
823 goto cleanup;
824 goto inserted;
825 } else {
826 int offset = (char *)s->here - bs->bh->b_data;
827
828 unlock_buffer(bs->bh);
829 if (ce) {
830 mb_cache_entry_release(ce);
831 ce = NULL;
832 }
833 ea_bdebug(bs->bh, "cloning");
834 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
835 error = -ENOMEM;
836 if (s->base == NULL)
837 goto cleanup;
838 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
839 s->first = ENTRY(header(s->base)+1);
840 header(s->base)->h_refcount = cpu_to_le32(1);
841 s->here = ENTRY(s->base + offset);
842 s->end = s->base + bs->bh->b_size;
843 }
844 } else {
845 /* Allocate a buffer where we construct the new block. */
846 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
847 /* assert(header == s->base) */
848 error = -ENOMEM;
849 if (s->base == NULL)
850 goto cleanup;
851 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
852 header(s->base)->h_blocks = cpu_to_le32(1);
853 header(s->base)->h_refcount = cpu_to_le32(1);
854 s->first = ENTRY(header(s->base)+1);
855 s->here = ENTRY(header(s->base)+1);
856 s->end = s->base + sb->s_blocksize;
857 }
858
859 error = ext4_xattr_set_entry(i, s);
860 if (error == -EIO)
861 goto bad_block;
862 if (error)
863 goto cleanup;
864 if (!IS_LAST_ENTRY(s->first))
865 ext4_xattr_rehash(header(s->base), s->here);
866
867 inserted:
868 if (!IS_LAST_ENTRY(s->first)) {
869 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
870 if (new_bh) {
871 /* We found an identical block in the cache. */
872 if (new_bh == bs->bh)
873 ea_bdebug(new_bh, "keeping");
874 else {
875 /* The old block is released after updating
876 the inode. */
877 error = dquot_alloc_block(inode,
878 EXT4_C2B(EXT4_SB(sb), 1));
879 if (error)
880 goto cleanup;
881 BUFFER_TRACE(new_bh, "get_write_access");
882 error = ext4_journal_get_write_access(handle,
883 new_bh);
884 if (error)
885 goto cleanup_dquot;
886 lock_buffer(new_bh);
887 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
888 ea_bdebug(new_bh, "reusing; refcount now=%d",
889 le32_to_cpu(BHDR(new_bh)->h_refcount));
890 unlock_buffer(new_bh);
891 error = ext4_handle_dirty_xattr_block(handle,
892 inode,
893 new_bh);
894 if (error)
895 goto cleanup_dquot;
896 }
897 mb_cache_entry_release(ce);
898 ce = NULL;
899 } else if (bs->bh && s->base == bs->bh->b_data) {
900 /* We were modifying this block in-place. */
901 ea_bdebug(bs->bh, "keeping this block");
902 new_bh = bs->bh;
903 get_bh(new_bh);
904 } else {
905 /* We need to allocate a new block */
906 ext4_fsblk_t goal, block;
907
908 goal = ext4_group_first_block_no(sb,
909 EXT4_I(inode)->i_block_group);
910
911 /* non-extent files can't have physical blocks past 2^32 */
912 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
913 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
914
915 block = ext4_new_meta_blocks(handle, inode, goal, 0,
916 NULL, &error);
917 if (error)
918 goto cleanup;
919
920 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
921 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
922
923 ea_idebug(inode, "creating block %llu",
924 (unsigned long long)block);
925
926 new_bh = sb_getblk(sb, block);
927 if (unlikely(!new_bh)) {
928 error = -ENOMEM;
929 getblk_failed:
930 ext4_free_blocks(handle, inode, NULL, block, 1,
931 EXT4_FREE_BLOCKS_METADATA);
932 goto cleanup;
933 }
934 lock_buffer(new_bh);
935 error = ext4_journal_get_create_access(handle, new_bh);
936 if (error) {
937 unlock_buffer(new_bh);
938 error = -EIO;
939 goto getblk_failed;
940 }
941 memcpy(new_bh->b_data, s->base, new_bh->b_size);
942 set_buffer_uptodate(new_bh);
943 unlock_buffer(new_bh);
944 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
945 error = ext4_handle_dirty_xattr_block(handle,
946 inode, new_bh);
947 if (error)
948 goto cleanup;
949 }
950 }
951
952 /* Update the inode. */
953 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
954
955 /* Drop the previous xattr block. */
956 if (bs->bh && bs->bh != new_bh)
957 ext4_xattr_release_block(handle, inode, bs->bh);
958 error = 0;
959
960 cleanup:
961 if (ce)
962 mb_cache_entry_release(ce);
963 brelse(new_bh);
964 if (!(bs->bh && s->base == bs->bh->b_data))
965 kfree(s->base);
966
967 return error;
968
969 cleanup_dquot:
970 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
971 goto cleanup;
972
973 bad_block:
974 EXT4_ERROR_INODE(inode, "bad block %llu",
975 EXT4_I(inode)->i_file_acl);
976 goto cleanup;
977
978 #undef header
979 }
980
981 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
982 struct ext4_xattr_ibody_find *is)
983 {
984 struct ext4_xattr_ibody_header *header;
985 struct ext4_inode *raw_inode;
986 int error;
987
988 if (EXT4_I(inode)->i_extra_isize == 0)
989 return 0;
990 raw_inode = ext4_raw_inode(&is->iloc);
991 header = IHDR(inode, raw_inode);
992 is->s.base = is->s.first = IFIRST(header);
993 is->s.here = is->s.first;
994 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
995 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
996 error = ext4_xattr_check_names(IFIRST(header), is->s.end,
997 IFIRST(header));
998 if (error)
999 return error;
1000 /* Find the named attribute. */
1001 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1002 i->name, is->s.end -
1003 (void *)is->s.base, 0);
1004 if (error && error != -ENODATA)
1005 return error;
1006 is->s.not_found = error;
1007 }
1008 return 0;
1009 }
1010
1011 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1012 struct ext4_xattr_info *i,
1013 struct ext4_xattr_ibody_find *is)
1014 {
1015 struct ext4_xattr_ibody_header *header;
1016 struct ext4_xattr_search *s = &is->s;
1017 int error;
1018
1019 if (EXT4_I(inode)->i_extra_isize == 0)
1020 return -ENOSPC;
1021 error = ext4_xattr_set_entry(i, s);
1022 if (error) {
1023 if (error == -ENOSPC &&
1024 ext4_has_inline_data(inode)) {
1025 error = ext4_try_to_evict_inline_data(handle, inode,
1026 EXT4_XATTR_LEN(strlen(i->name) +
1027 EXT4_XATTR_SIZE(i->value_len)));
1028 if (error)
1029 return error;
1030 error = ext4_xattr_ibody_find(inode, i, is);
1031 if (error)
1032 return error;
1033 error = ext4_xattr_set_entry(i, s);
1034 }
1035 if (error)
1036 return error;
1037 }
1038 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1039 if (!IS_LAST_ENTRY(s->first)) {
1040 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1041 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1042 } else {
1043 header->h_magic = cpu_to_le32(0);
1044 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1045 }
1046 return 0;
1047 }
1048
1049 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1050 struct ext4_xattr_info *i,
1051 struct ext4_xattr_ibody_find *is)
1052 {
1053 struct ext4_xattr_ibody_header *header;
1054 struct ext4_xattr_search *s = &is->s;
1055 int error;
1056
1057 if (EXT4_I(inode)->i_extra_isize == 0)
1058 return -ENOSPC;
1059 error = ext4_xattr_set_entry(i, s);
1060 if (error)
1061 return error;
1062 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1063 if (!IS_LAST_ENTRY(s->first)) {
1064 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1065 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1066 } else {
1067 header->h_magic = cpu_to_le32(0);
1068 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1069 }
1070 return 0;
1071 }
1072
1073 /*
1074 * ext4_xattr_set_handle()
1075 *
1076 * Create, replace or remove an extended attribute for this inode. Value
1077 * is NULL to remove an existing extended attribute, and non-NULL to
1078 * either replace an existing extended attribute, or create a new extended
1079 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1080 * specify that an extended attribute must exist and must not exist
1081 * previous to the call, respectively.
1082 *
1083 * Returns 0, or a negative error number on failure.
1084 */
1085 int
1086 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1087 const char *name, const void *value, size_t value_len,
1088 int flags)
1089 {
1090 struct ext4_xattr_info i = {
1091 .name_index = name_index,
1092 .name = name,
1093 .value = value,
1094 .value_len = value_len,
1095
1096 };
1097 struct ext4_xattr_ibody_find is = {
1098 .s = { .not_found = -ENODATA, },
1099 };
1100 struct ext4_xattr_block_find bs = {
1101 .s = { .not_found = -ENODATA, },
1102 };
1103 unsigned long no_expand;
1104 int error;
1105
1106 if (!name)
1107 return -EINVAL;
1108 if (strlen(name) > 255)
1109 return -ERANGE;
1110 down_write(&EXT4_I(inode)->xattr_sem);
1111 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1112 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1113
1114 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1115 if (error)
1116 goto cleanup;
1117
1118 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1119 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1120 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1121 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1122 }
1123
1124 error = ext4_xattr_ibody_find(inode, &i, &is);
1125 if (error)
1126 goto cleanup;
1127 if (is.s.not_found)
1128 error = ext4_xattr_block_find(inode, &i, &bs);
1129 if (error)
1130 goto cleanup;
1131 if (is.s.not_found && bs.s.not_found) {
1132 error = -ENODATA;
1133 if (flags & XATTR_REPLACE)
1134 goto cleanup;
1135 error = 0;
1136 if (!value)
1137 goto cleanup;
1138 } else {
1139 error = -EEXIST;
1140 if (flags & XATTR_CREATE)
1141 goto cleanup;
1142 }
1143 if (!value) {
1144 if (!is.s.not_found)
1145 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1146 else if (!bs.s.not_found)
1147 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1148 } else {
1149 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1150 if (!error && !bs.s.not_found) {
1151 i.value = NULL;
1152 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1153 } else if (error == -ENOSPC) {
1154 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1155 error = ext4_xattr_block_find(inode, &i, &bs);
1156 if (error)
1157 goto cleanup;
1158 }
1159 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1160 if (error)
1161 goto cleanup;
1162 if (!is.s.not_found) {
1163 i.value = NULL;
1164 error = ext4_xattr_ibody_set(handle, inode, &i,
1165 &is);
1166 }
1167 }
1168 }
1169 if (!error) {
1170 ext4_xattr_update_super_block(handle, inode->i_sb);
1171 inode->i_ctime = ext4_current_time(inode);
1172 if (!value)
1173 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1174 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1175 /*
1176 * The bh is consumed by ext4_mark_iloc_dirty, even with
1177 * error != 0.
1178 */
1179 is.iloc.bh = NULL;
1180 if (IS_SYNC(inode))
1181 ext4_handle_sync(handle);
1182 }
1183
1184 cleanup:
1185 brelse(is.iloc.bh);
1186 brelse(bs.bh);
1187 if (no_expand == 0)
1188 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1189 up_write(&EXT4_I(inode)->xattr_sem);
1190 return error;
1191 }
1192
1193 /*
1194 * ext4_xattr_set()
1195 *
1196 * Like ext4_xattr_set_handle, but start from an inode. This extended
1197 * attribute modification is a filesystem transaction by itself.
1198 *
1199 * Returns 0, or a negative error number on failure.
1200 */
1201 int
1202 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1203 const void *value, size_t value_len, int flags)
1204 {
1205 handle_t *handle;
1206 int error, retries = 0;
1207 int credits = ext4_jbd2_credits_xattr(inode);
1208
1209 retry:
1210 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1211 if (IS_ERR(handle)) {
1212 error = PTR_ERR(handle);
1213 } else {
1214 int error2;
1215
1216 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1217 value, value_len, flags);
1218 error2 = ext4_journal_stop(handle);
1219 if (error == -ENOSPC &&
1220 ext4_should_retry_alloc(inode->i_sb, &retries))
1221 goto retry;
1222 if (error == 0)
1223 error = error2;
1224 }
1225
1226 return error;
1227 }
1228
1229 /*
1230 * Shift the EA entries in the inode to create space for the increased
1231 * i_extra_isize.
1232 */
1233 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1234 int value_offs_shift, void *to,
1235 void *from, size_t n, int blocksize)
1236 {
1237 struct ext4_xattr_entry *last = entry;
1238 int new_offs;
1239
1240 /* Adjust the value offsets of the entries */
1241 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1242 if (!last->e_value_block && last->e_value_size) {
1243 new_offs = le16_to_cpu(last->e_value_offs) +
1244 value_offs_shift;
1245 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1246 > blocksize);
1247 last->e_value_offs = cpu_to_le16(new_offs);
1248 }
1249 }
1250 /* Shift the entries by n bytes */
1251 memmove(to, from, n);
1252 }
1253
1254 /*
1255 * Expand an inode by new_extra_isize bytes when EAs are present.
1256 * Returns 0 on success or negative error number on failure.
1257 */
1258 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1259 struct ext4_inode *raw_inode, handle_t *handle)
1260 {
1261 struct ext4_xattr_ibody_header *header;
1262 struct ext4_xattr_entry *entry, *last, *first;
1263 struct buffer_head *bh = NULL;
1264 struct ext4_xattr_ibody_find *is = NULL;
1265 struct ext4_xattr_block_find *bs = NULL;
1266 char *buffer = NULL, *b_entry_name = NULL;
1267 size_t min_offs, free;
1268 int total_ino;
1269 void *base, *start, *end;
1270 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1271 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1272
1273 down_write(&EXT4_I(inode)->xattr_sem);
1274 retry:
1275 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1276 up_write(&EXT4_I(inode)->xattr_sem);
1277 return 0;
1278 }
1279
1280 header = IHDR(inode, raw_inode);
1281 entry = IFIRST(header);
1282
1283 /*
1284 * Check if enough free space is available in the inode to shift the
1285 * entries ahead by new_extra_isize.
1286 */
1287
1288 base = start = entry;
1289 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1290 min_offs = end - base;
1291 last = entry;
1292 total_ino = sizeof(struct ext4_xattr_ibody_header);
1293
1294 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1295 if (free >= new_extra_isize) {
1296 entry = IFIRST(header);
1297 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1298 - new_extra_isize, (void *)raw_inode +
1299 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1300 (void *)header, total_ino,
1301 inode->i_sb->s_blocksize);
1302 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1303 error = 0;
1304 goto cleanup;
1305 }
1306
1307 /*
1308 * Enough free space isn't available in the inode, check if
1309 * EA block can hold new_extra_isize bytes.
1310 */
1311 if (EXT4_I(inode)->i_file_acl) {
1312 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1313 error = -EIO;
1314 if (!bh)
1315 goto cleanup;
1316 if (ext4_xattr_check_block(inode, bh)) {
1317 EXT4_ERROR_INODE(inode, "bad block %llu",
1318 EXT4_I(inode)->i_file_acl);
1319 error = -EIO;
1320 goto cleanup;
1321 }
1322 base = BHDR(bh);
1323 first = BFIRST(bh);
1324 end = bh->b_data + bh->b_size;
1325 min_offs = end - base;
1326 free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1327 if (free < new_extra_isize) {
1328 if (!tried_min_extra_isize && s_min_extra_isize) {
1329 tried_min_extra_isize++;
1330 new_extra_isize = s_min_extra_isize;
1331 brelse(bh);
1332 goto retry;
1333 }
1334 error = -1;
1335 goto cleanup;
1336 }
1337 } else {
1338 free = inode->i_sb->s_blocksize;
1339 }
1340
1341 while (new_extra_isize > 0) {
1342 size_t offs, size, entry_size;
1343 struct ext4_xattr_entry *small_entry = NULL;
1344 struct ext4_xattr_info i = {
1345 .value = NULL,
1346 .value_len = 0,
1347 };
1348 unsigned int total_size; /* EA entry size + value size */
1349 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1350 unsigned int min_total_size = ~0U;
1351
1352 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1353 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1354 if (!is || !bs) {
1355 error = -ENOMEM;
1356 goto cleanup;
1357 }
1358
1359 is->s.not_found = -ENODATA;
1360 bs->s.not_found = -ENODATA;
1361 is->iloc.bh = NULL;
1362 bs->bh = NULL;
1363
1364 last = IFIRST(header);
1365 /* Find the entry best suited to be pushed into EA block */
1366 entry = NULL;
1367 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1368 total_size =
1369 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1370 EXT4_XATTR_LEN(last->e_name_len);
1371 if (total_size <= free && total_size < min_total_size) {
1372 if (total_size < new_extra_isize) {
1373 small_entry = last;
1374 } else {
1375 entry = last;
1376 min_total_size = total_size;
1377 }
1378 }
1379 }
1380
1381 if (entry == NULL) {
1382 if (small_entry) {
1383 entry = small_entry;
1384 } else {
1385 if (!tried_min_extra_isize &&
1386 s_min_extra_isize) {
1387 tried_min_extra_isize++;
1388 new_extra_isize = s_min_extra_isize;
1389 kfree(is); is = NULL;
1390 kfree(bs); bs = NULL;
1391 brelse(bh);
1392 goto retry;
1393 }
1394 error = -1;
1395 goto cleanup;
1396 }
1397 }
1398 offs = le16_to_cpu(entry->e_value_offs);
1399 size = le32_to_cpu(entry->e_value_size);
1400 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1401 i.name_index = entry->e_name_index,
1402 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1403 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1404 if (!buffer || !b_entry_name) {
1405 error = -ENOMEM;
1406 goto cleanup;
1407 }
1408 /* Save the entry name and the entry value */
1409 memcpy(buffer, (void *)IFIRST(header) + offs,
1410 EXT4_XATTR_SIZE(size));
1411 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1412 b_entry_name[entry->e_name_len] = '\0';
1413 i.name = b_entry_name;
1414
1415 error = ext4_get_inode_loc(inode, &is->iloc);
1416 if (error)
1417 goto cleanup;
1418
1419 error = ext4_xattr_ibody_find(inode, &i, is);
1420 if (error)
1421 goto cleanup;
1422
1423 /* Remove the chosen entry from the inode */
1424 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1425 if (error)
1426 goto cleanup;
1427
1428 entry = IFIRST(header);
1429 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1430 shift_bytes = new_extra_isize;
1431 else
1432 shift_bytes = entry_size + size;
1433 /* Adjust the offsets and shift the remaining entries ahead */
1434 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1435 shift_bytes, (void *)raw_inode +
1436 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1437 (void *)header, total_ino - entry_size,
1438 inode->i_sb->s_blocksize);
1439
1440 extra_isize += shift_bytes;
1441 new_extra_isize -= shift_bytes;
1442 EXT4_I(inode)->i_extra_isize = extra_isize;
1443
1444 i.name = b_entry_name;
1445 i.value = buffer;
1446 i.value_len = size;
1447 error = ext4_xattr_block_find(inode, &i, bs);
1448 if (error)
1449 goto cleanup;
1450
1451 /* Add entry which was removed from the inode into the block */
1452 error = ext4_xattr_block_set(handle, inode, &i, bs);
1453 if (error)
1454 goto cleanup;
1455 kfree(b_entry_name);
1456 kfree(buffer);
1457 b_entry_name = NULL;
1458 buffer = NULL;
1459 brelse(is->iloc.bh);
1460 kfree(is);
1461 kfree(bs);
1462 }
1463 brelse(bh);
1464 up_write(&EXT4_I(inode)->xattr_sem);
1465 return 0;
1466
1467 cleanup:
1468 kfree(b_entry_name);
1469 kfree(buffer);
1470 if (is)
1471 brelse(is->iloc.bh);
1472 kfree(is);
1473 kfree(bs);
1474 brelse(bh);
1475 up_write(&EXT4_I(inode)->xattr_sem);
1476 return error;
1477 }
1478
1479
1480
1481 /*
1482 * ext4_xattr_delete_inode()
1483 *
1484 * Free extended attribute resources associated with this inode. This
1485 * is called immediately before an inode is freed. We have exclusive
1486 * access to the inode.
1487 */
1488 void
1489 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1490 {
1491 struct buffer_head *bh = NULL;
1492
1493 if (!EXT4_I(inode)->i_file_acl)
1494 goto cleanup;
1495 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1496 if (!bh) {
1497 EXT4_ERROR_INODE(inode, "block %llu read error",
1498 EXT4_I(inode)->i_file_acl);
1499 goto cleanup;
1500 }
1501 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1502 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1503 EXT4_ERROR_INODE(inode, "bad block %llu",
1504 EXT4_I(inode)->i_file_acl);
1505 goto cleanup;
1506 }
1507 ext4_xattr_release_block(handle, inode, bh);
1508 EXT4_I(inode)->i_file_acl = 0;
1509
1510 cleanup:
1511 brelse(bh);
1512 }
1513
1514 /*
1515 * ext4_xattr_put_super()
1516 *
1517 * This is called when a file system is unmounted.
1518 */
1519 void
1520 ext4_xattr_put_super(struct super_block *sb)
1521 {
1522 mb_cache_shrink(sb->s_bdev);
1523 }
1524
1525 /*
1526 * ext4_xattr_cache_insert()
1527 *
1528 * Create a new entry in the extended attribute cache, and insert
1529 * it unless such an entry is already in the cache.
1530 *
1531 * Returns 0, or a negative error number on failure.
1532 */
1533 static void
1534 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1535 {
1536 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1537 struct mb_cache_entry *ce;
1538 int error;
1539
1540 ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS);
1541 if (!ce) {
1542 ea_bdebug(bh, "out of memory");
1543 return;
1544 }
1545 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1546 if (error) {
1547 mb_cache_entry_free(ce);
1548 if (error == -EBUSY) {
1549 ea_bdebug(bh, "already in cache");
1550 error = 0;
1551 }
1552 } else {
1553 ea_bdebug(bh, "inserting [%x]", (int)hash);
1554 mb_cache_entry_release(ce);
1555 }
1556 }
1557
1558 /*
1559 * ext4_xattr_cmp()
1560 *
1561 * Compare two extended attribute blocks for equality.
1562 *
1563 * Returns 0 if the blocks are equal, 1 if they differ, and
1564 * a negative error number on errors.
1565 */
1566 static int
1567 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1568 struct ext4_xattr_header *header2)
1569 {
1570 struct ext4_xattr_entry *entry1, *entry2;
1571
1572 entry1 = ENTRY(header1+1);
1573 entry2 = ENTRY(header2+1);
1574 while (!IS_LAST_ENTRY(entry1)) {
1575 if (IS_LAST_ENTRY(entry2))
1576 return 1;
1577 if (entry1->e_hash != entry2->e_hash ||
1578 entry1->e_name_index != entry2->e_name_index ||
1579 entry1->e_name_len != entry2->e_name_len ||
1580 entry1->e_value_size != entry2->e_value_size ||
1581 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1582 return 1;
1583 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1584 return -EIO;
1585 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1586 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1587 le32_to_cpu(entry1->e_value_size)))
1588 return 1;
1589
1590 entry1 = EXT4_XATTR_NEXT(entry1);
1591 entry2 = EXT4_XATTR_NEXT(entry2);
1592 }
1593 if (!IS_LAST_ENTRY(entry2))
1594 return 1;
1595 return 0;
1596 }
1597
1598 /*
1599 * ext4_xattr_cache_find()
1600 *
1601 * Find an identical extended attribute block.
1602 *
1603 * Returns a pointer to the block found, or NULL if such a block was
1604 * not found or an error occurred.
1605 */
1606 static struct buffer_head *
1607 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1608 struct mb_cache_entry **pce)
1609 {
1610 __u32 hash = le32_to_cpu(header->h_hash);
1611 struct mb_cache_entry *ce;
1612 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1613
1614 if (!header->h_hash)
1615 return NULL; /* never share */
1616 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1617 again:
1618 ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev,
1619 hash);
1620 while (ce) {
1621 struct buffer_head *bh;
1622
1623 if (IS_ERR(ce)) {
1624 if (PTR_ERR(ce) == -EAGAIN)
1625 goto again;
1626 break;
1627 }
1628 bh = sb_bread(inode->i_sb, ce->e_block);
1629 if (!bh) {
1630 EXT4_ERROR_INODE(inode, "block %lu read error",
1631 (unsigned long) ce->e_block);
1632 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1633 EXT4_XATTR_REFCOUNT_MAX) {
1634 ea_idebug(inode, "block %lu refcount %d>=%d",
1635 (unsigned long) ce->e_block,
1636 le32_to_cpu(BHDR(bh)->h_refcount),
1637 EXT4_XATTR_REFCOUNT_MAX);
1638 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1639 *pce = ce;
1640 return bh;
1641 }
1642 brelse(bh);
1643 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1644 }
1645 return NULL;
1646 }
1647
1648 #define NAME_HASH_SHIFT 5
1649 #define VALUE_HASH_SHIFT 16
1650
1651 /*
1652 * ext4_xattr_hash_entry()
1653 *
1654 * Compute the hash of an extended attribute.
1655 */
1656 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1657 struct ext4_xattr_entry *entry)
1658 {
1659 __u32 hash = 0;
1660 char *name = entry->e_name;
1661 int n;
1662
1663 for (n = 0; n < entry->e_name_len; n++) {
1664 hash = (hash << NAME_HASH_SHIFT) ^
1665 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1666 *name++;
1667 }
1668
1669 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1670 __le32 *value = (__le32 *)((char *)header +
1671 le16_to_cpu(entry->e_value_offs));
1672 for (n = (le32_to_cpu(entry->e_value_size) +
1673 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1674 hash = (hash << VALUE_HASH_SHIFT) ^
1675 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1676 le32_to_cpu(*value++);
1677 }
1678 }
1679 entry->e_hash = cpu_to_le32(hash);
1680 }
1681
1682 #undef NAME_HASH_SHIFT
1683 #undef VALUE_HASH_SHIFT
1684
1685 #define BLOCK_HASH_SHIFT 16
1686
1687 /*
1688 * ext4_xattr_rehash()
1689 *
1690 * Re-compute the extended attribute hash value after an entry has changed.
1691 */
1692 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1693 struct ext4_xattr_entry *entry)
1694 {
1695 struct ext4_xattr_entry *here;
1696 __u32 hash = 0;
1697
1698 ext4_xattr_hash_entry(header, entry);
1699 here = ENTRY(header+1);
1700 while (!IS_LAST_ENTRY(here)) {
1701 if (!here->e_hash) {
1702 /* Block is not shared if an entry's hash value == 0 */
1703 hash = 0;
1704 break;
1705 }
1706 hash = (hash << BLOCK_HASH_SHIFT) ^
1707 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1708 le32_to_cpu(here->e_hash);
1709 here = EXT4_XATTR_NEXT(here);
1710 }
1711 header->h_hash = cpu_to_le32(hash);
1712 }
1713
1714 #undef BLOCK_HASH_SHIFT
1715
1716 #define HASH_BUCKET_BITS 10
1717
1718 struct mb_cache *
1719 ext4_xattr_create_cache(char *name)
1720 {
1721 return mb_cache_create(name, HASH_BUCKET_BITS);
1722 }
1723
1724 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1725 {
1726 if (cache)
1727 mb_cache_destroy(cache);
1728 }
1729
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