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Merge remote-tracking branch 'omap_dss2/for-next'
[deliverable/linux.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 "ext4_jbd2.h"
59 #include "ext4.h"
60 #include "xattr.h"
61 #include "acl.h"
62
63 #ifdef EXT4_XATTR_DEBUG
64 # define ea_idebug(inode, f...) do { \
65 printk(KERN_DEBUG "inode %s:%lu: ", \
66 inode->i_sb->s_id, inode->i_ino); \
67 printk(f); \
68 printk("\n"); \
69 } while (0)
70 # define ea_bdebug(bh, f...) do { \
71 printk(KERN_DEBUG "block %pg:%lu: ", \
72 bh->b_bdev, (unsigned long) bh->b_blocknr); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76 #else
77 # define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
78 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
79 #endif
80
81 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
82 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
83 struct ext4_xattr_header *,
84 struct mb_cache_entry **);
85 static void ext4_xattr_rehash(struct ext4_xattr_header *,
86 struct ext4_xattr_entry *);
87 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
88 size_t buffer_size);
89
90 static const struct xattr_handler *ext4_xattr_handler_map[] = {
91 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
92 #ifdef CONFIG_EXT4_FS_POSIX_ACL
93 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
94 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
95 #endif
96 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
97 #ifdef CONFIG_EXT4_FS_SECURITY
98 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
99 #endif
100 };
101
102 const struct xattr_handler *ext4_xattr_handlers[] = {
103 &ext4_xattr_user_handler,
104 &ext4_xattr_trusted_handler,
105 #ifdef CONFIG_EXT4_FS_POSIX_ACL
106 &posix_acl_access_xattr_handler,
107 &posix_acl_default_xattr_handler,
108 #endif
109 #ifdef CONFIG_EXT4_FS_SECURITY
110 &ext4_xattr_security_handler,
111 #endif
112 NULL
113 };
114
115 #define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \
116 inode->i_sb->s_fs_info)->s_mb_cache)
117
118 static __le32 ext4_xattr_block_csum(struct inode *inode,
119 sector_t block_nr,
120 struct ext4_xattr_header *hdr)
121 {
122 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
123 __u32 csum;
124 __le64 dsk_block_nr = cpu_to_le64(block_nr);
125 __u32 dummy_csum = 0;
126 int offset = offsetof(struct ext4_xattr_header, h_checksum);
127
128 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
129 sizeof(dsk_block_nr));
130 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
131 csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
132 offset += sizeof(dummy_csum);
133 csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
134 EXT4_BLOCK_SIZE(inode->i_sb) - offset);
135
136 return cpu_to_le32(csum);
137 }
138
139 static int ext4_xattr_block_csum_verify(struct inode *inode,
140 sector_t block_nr,
141 struct ext4_xattr_header *hdr)
142 {
143 if (ext4_has_metadata_csum(inode->i_sb) &&
144 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
145 return 0;
146 return 1;
147 }
148
149 static void ext4_xattr_block_csum_set(struct inode *inode,
150 sector_t block_nr,
151 struct ext4_xattr_header *hdr)
152 {
153 if (!ext4_has_metadata_csum(inode->i_sb))
154 return;
155
156 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
157 }
158
159 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
160 struct inode *inode,
161 struct buffer_head *bh)
162 {
163 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
164 return ext4_handle_dirty_metadata(handle, inode, bh);
165 }
166
167 static inline const struct xattr_handler *
168 ext4_xattr_handler(int name_index)
169 {
170 const struct xattr_handler *handler = NULL;
171
172 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
173 handler = ext4_xattr_handler_map[name_index];
174 return handler;
175 }
176
177 /*
178 * Inode operation listxattr()
179 *
180 * d_inode(dentry)->i_mutex: don't care
181 */
182 ssize_t
183 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
184 {
185 return ext4_xattr_list(dentry, buffer, size);
186 }
187
188 static int
189 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
190 void *value_start)
191 {
192 struct ext4_xattr_entry *e = entry;
193
194 while (!IS_LAST_ENTRY(e)) {
195 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
196 if ((void *)next >= end)
197 return -EFSCORRUPTED;
198 e = next;
199 }
200
201 while (!IS_LAST_ENTRY(entry)) {
202 if (entry->e_value_block != 0)
203 return -EFSCORRUPTED;
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 -EFSCORRUPTED;
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 -EFSCORRUPTED;
227 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
228 return -EFSBADCRC;
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 int
237 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
238 void *end, const char *function, unsigned int line)
239 {
240 struct ext4_xattr_entry *entry = IFIRST(header);
241 int error = -EFSCORRUPTED;
242
243 if (((void *) header >= end) ||
244 (header->h_magic != le32_to_cpu(EXT4_XATTR_MAGIC)))
245 goto errout;
246 error = ext4_xattr_check_names(entry, end, entry);
247 errout:
248 if (error)
249 __ext4_error_inode(inode, function, line, 0,
250 "corrupted in-inode xattr");
251 return error;
252 }
253
254 #define xattr_check_inode(inode, header, end) \
255 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
256
257 static inline int
258 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
259 {
260 size_t value_size = le32_to_cpu(entry->e_value_size);
261
262 if (entry->e_value_block != 0 || value_size > size ||
263 le16_to_cpu(entry->e_value_offs) + value_size > size)
264 return -EFSCORRUPTED;
265 return 0;
266 }
267
268 static int
269 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
270 const char *name, size_t size, int sorted)
271 {
272 struct ext4_xattr_entry *entry;
273 size_t name_len;
274 int cmp = 1;
275
276 if (name == NULL)
277 return -EINVAL;
278 name_len = strlen(name);
279 entry = *pentry;
280 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
281 cmp = name_index - entry->e_name_index;
282 if (!cmp)
283 cmp = name_len - entry->e_name_len;
284 if (!cmp)
285 cmp = memcmp(name, entry->e_name, name_len);
286 if (cmp <= 0 && (sorted || cmp == 0))
287 break;
288 }
289 *pentry = entry;
290 if (!cmp && ext4_xattr_check_entry(entry, size))
291 return -EFSCORRUPTED;
292 return cmp ? -ENODATA : 0;
293 }
294
295 static int
296 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
297 void *buffer, size_t buffer_size)
298 {
299 struct buffer_head *bh = NULL;
300 struct ext4_xattr_entry *entry;
301 size_t size;
302 int error;
303 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
304
305 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
306 name_index, name, buffer, (long)buffer_size);
307
308 error = -ENODATA;
309 if (!EXT4_I(inode)->i_file_acl)
310 goto cleanup;
311 ea_idebug(inode, "reading block %llu",
312 (unsigned long long)EXT4_I(inode)->i_file_acl);
313 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
314 if (!bh)
315 goto cleanup;
316 ea_bdebug(bh, "b_count=%d, refcount=%d",
317 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
318 if (ext4_xattr_check_block(inode, bh)) {
319 bad_block:
320 EXT4_ERROR_INODE(inode, "bad block %llu",
321 EXT4_I(inode)->i_file_acl);
322 error = -EFSCORRUPTED;
323 goto cleanup;
324 }
325 ext4_xattr_cache_insert(ext4_mb_cache, bh);
326 entry = BFIRST(bh);
327 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
328 if (error == -EFSCORRUPTED)
329 goto bad_block;
330 if (error)
331 goto cleanup;
332 size = le32_to_cpu(entry->e_value_size);
333 if (buffer) {
334 error = -ERANGE;
335 if (size > buffer_size)
336 goto cleanup;
337 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
338 size);
339 }
340 error = size;
341
342 cleanup:
343 brelse(bh);
344 return error;
345 }
346
347 int
348 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
349 void *buffer, size_t buffer_size)
350 {
351 struct ext4_xattr_ibody_header *header;
352 struct ext4_xattr_entry *entry;
353 struct ext4_inode *raw_inode;
354 struct ext4_iloc iloc;
355 size_t size;
356 void *end;
357 int error;
358
359 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
360 return -ENODATA;
361 error = ext4_get_inode_loc(inode, &iloc);
362 if (error)
363 return error;
364 raw_inode = ext4_raw_inode(&iloc);
365 header = IHDR(inode, raw_inode);
366 entry = IFIRST(header);
367 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
368 error = xattr_check_inode(inode, header, end);
369 if (error)
370 goto cleanup;
371 error = ext4_xattr_find_entry(&entry, name_index, name,
372 end - (void *)entry, 0);
373 if (error)
374 goto cleanup;
375 size = le32_to_cpu(entry->e_value_size);
376 if (buffer) {
377 error = -ERANGE;
378 if (size > buffer_size)
379 goto cleanup;
380 memcpy(buffer, (void *)IFIRST(header) +
381 le16_to_cpu(entry->e_value_offs), size);
382 }
383 error = size;
384
385 cleanup:
386 brelse(iloc.bh);
387 return error;
388 }
389
390 /*
391 * ext4_xattr_get()
392 *
393 * Copy an extended attribute into the buffer
394 * provided, or compute the buffer size required.
395 * Buffer is NULL to compute the size of the buffer required.
396 *
397 * Returns a negative error number on failure, or the number of bytes
398 * used / required on success.
399 */
400 int
401 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
402 void *buffer, size_t buffer_size)
403 {
404 int error;
405
406 if (strlen(name) > 255)
407 return -ERANGE;
408
409 down_read(&EXT4_I(inode)->xattr_sem);
410 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
411 buffer_size);
412 if (error == -ENODATA)
413 error = ext4_xattr_block_get(inode, name_index, name, buffer,
414 buffer_size);
415 up_read(&EXT4_I(inode)->xattr_sem);
416 return error;
417 }
418
419 static int
420 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
421 char *buffer, size_t buffer_size)
422 {
423 size_t rest = buffer_size;
424
425 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
426 const struct xattr_handler *handler =
427 ext4_xattr_handler(entry->e_name_index);
428
429 if (handler && (!handler->list || handler->list(dentry))) {
430 const char *prefix = handler->prefix ?: handler->name;
431 size_t prefix_len = strlen(prefix);
432 size_t size = prefix_len + entry->e_name_len + 1;
433
434 if (buffer) {
435 if (size > rest)
436 return -ERANGE;
437 memcpy(buffer, prefix, prefix_len);
438 buffer += prefix_len;
439 memcpy(buffer, entry->e_name, entry->e_name_len);
440 buffer += entry->e_name_len;
441 *buffer++ = 0;
442 }
443 rest -= size;
444 }
445 }
446 return buffer_size - rest; /* total size */
447 }
448
449 static int
450 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
451 {
452 struct inode *inode = d_inode(dentry);
453 struct buffer_head *bh = NULL;
454 int error;
455 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
456
457 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
458 buffer, (long)buffer_size);
459
460 error = 0;
461 if (!EXT4_I(inode)->i_file_acl)
462 goto cleanup;
463 ea_idebug(inode, "reading block %llu",
464 (unsigned long long)EXT4_I(inode)->i_file_acl);
465 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
466 error = -EIO;
467 if (!bh)
468 goto cleanup;
469 ea_bdebug(bh, "b_count=%d, refcount=%d",
470 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
471 if (ext4_xattr_check_block(inode, bh)) {
472 EXT4_ERROR_INODE(inode, "bad block %llu",
473 EXT4_I(inode)->i_file_acl);
474 error = -EFSCORRUPTED;
475 goto cleanup;
476 }
477 ext4_xattr_cache_insert(ext4_mb_cache, bh);
478 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
479
480 cleanup:
481 brelse(bh);
482
483 return error;
484 }
485
486 static int
487 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
488 {
489 struct inode *inode = d_inode(dentry);
490 struct ext4_xattr_ibody_header *header;
491 struct ext4_inode *raw_inode;
492 struct ext4_iloc iloc;
493 void *end;
494 int error;
495
496 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
497 return 0;
498 error = ext4_get_inode_loc(inode, &iloc);
499 if (error)
500 return error;
501 raw_inode = ext4_raw_inode(&iloc);
502 header = IHDR(inode, raw_inode);
503 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
504 error = xattr_check_inode(inode, header, end);
505 if (error)
506 goto cleanup;
507 error = ext4_xattr_list_entries(dentry, IFIRST(header),
508 buffer, buffer_size);
509
510 cleanup:
511 brelse(iloc.bh);
512 return error;
513 }
514
515 /*
516 * ext4_xattr_list()
517 *
518 * Copy a list of attribute names into the buffer
519 * provided, or compute the buffer size required.
520 * Buffer is NULL to compute the size of the buffer required.
521 *
522 * Returns a negative error number on failure, or the number of bytes
523 * used / required on success.
524 */
525 static int
526 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
527 {
528 int ret, ret2;
529
530 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
531 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
532 if (ret < 0)
533 goto errout;
534 if (buffer) {
535 buffer += ret;
536 buffer_size -= ret;
537 }
538 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
539 if (ret < 0)
540 goto errout;
541 ret += ret2;
542 errout:
543 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
544 return ret;
545 }
546
547 /*
548 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
549 * not set, set it.
550 */
551 static void ext4_xattr_update_super_block(handle_t *handle,
552 struct super_block *sb)
553 {
554 if (ext4_has_feature_xattr(sb))
555 return;
556
557 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
558 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
559 ext4_set_feature_xattr(sb);
560 ext4_handle_dirty_super(handle, sb);
561 }
562 }
563
564 /*
565 * Release the xattr block BH: If the reference count is > 1, decrement it;
566 * otherwise free the block.
567 */
568 static void
569 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
570 struct buffer_head *bh)
571 {
572 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
573 u32 hash, ref;
574 int error = 0;
575
576 BUFFER_TRACE(bh, "get_write_access");
577 error = ext4_journal_get_write_access(handle, bh);
578 if (error)
579 goto out;
580
581 lock_buffer(bh);
582 hash = le32_to_cpu(BHDR(bh)->h_hash);
583 ref = le32_to_cpu(BHDR(bh)->h_refcount);
584 if (ref == 1) {
585 ea_bdebug(bh, "refcount now=0; freeing");
586 /*
587 * This must happen under buffer lock for
588 * ext4_xattr_block_set() to reliably detect freed block
589 */
590 mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
591 get_bh(bh);
592 unlock_buffer(bh);
593 ext4_free_blocks(handle, inode, bh, 0, 1,
594 EXT4_FREE_BLOCKS_METADATA |
595 EXT4_FREE_BLOCKS_FORGET);
596 } else {
597 ref--;
598 BHDR(bh)->h_refcount = cpu_to_le32(ref);
599 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
600 struct mb_cache_entry *ce;
601
602 ce = mb_cache_entry_get(ext4_mb_cache, hash,
603 bh->b_blocknr);
604 if (ce) {
605 ce->e_reusable = 1;
606 mb_cache_entry_put(ext4_mb_cache, ce);
607 }
608 }
609
610 /*
611 * Beware of this ugliness: Releasing of xattr block references
612 * from different inodes can race and so we have to protect
613 * from a race where someone else frees the block (and releases
614 * its journal_head) before we are done dirtying the buffer. In
615 * nojournal mode this race is harmless and we actually cannot
616 * call ext4_handle_dirty_xattr_block() with locked buffer as
617 * that function can call sync_dirty_buffer() so for that case
618 * we handle the dirtying after unlocking the buffer.
619 */
620 if (ext4_handle_valid(handle))
621 error = ext4_handle_dirty_xattr_block(handle, inode,
622 bh);
623 unlock_buffer(bh);
624 if (!ext4_handle_valid(handle))
625 error = ext4_handle_dirty_xattr_block(handle, inode,
626 bh);
627 if (IS_SYNC(inode))
628 ext4_handle_sync(handle);
629 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
630 ea_bdebug(bh, "refcount now=%d; releasing",
631 le32_to_cpu(BHDR(bh)->h_refcount));
632 }
633 out:
634 ext4_std_error(inode->i_sb, error);
635 return;
636 }
637
638 /*
639 * Find the available free space for EAs. This also returns the total number of
640 * bytes used by EA entries.
641 */
642 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
643 size_t *min_offs, void *base, int *total)
644 {
645 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
646 if (last->e_value_size) {
647 size_t offs = le16_to_cpu(last->e_value_offs);
648 if (offs < *min_offs)
649 *min_offs = offs;
650 }
651 if (total)
652 *total += EXT4_XATTR_LEN(last->e_name_len);
653 }
654 return (*min_offs - ((void *)last - base) - sizeof(__u32));
655 }
656
657 static int
658 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
659 {
660 struct ext4_xattr_entry *last;
661 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
662
663 /* Compute min_offs and last. */
664 last = s->first;
665 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
666 if (last->e_value_size) {
667 size_t offs = le16_to_cpu(last->e_value_offs);
668 if (offs < min_offs)
669 min_offs = offs;
670 }
671 }
672 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
673 if (!s->not_found) {
674 if (s->here->e_value_size) {
675 size_t size = le32_to_cpu(s->here->e_value_size);
676 free += EXT4_XATTR_SIZE(size);
677 }
678 free += EXT4_XATTR_LEN(name_len);
679 }
680 if (i->value) {
681 if (free < EXT4_XATTR_LEN(name_len) +
682 EXT4_XATTR_SIZE(i->value_len))
683 return -ENOSPC;
684 }
685
686 if (i->value && s->not_found) {
687 /* Insert the new name. */
688 size_t size = EXT4_XATTR_LEN(name_len);
689 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
690 memmove((void *)s->here + size, s->here, rest);
691 memset(s->here, 0, size);
692 s->here->e_name_index = i->name_index;
693 s->here->e_name_len = name_len;
694 memcpy(s->here->e_name, i->name, name_len);
695 } else {
696 if (s->here->e_value_size) {
697 void *first_val = s->base + min_offs;
698 size_t offs = le16_to_cpu(s->here->e_value_offs);
699 void *val = s->base + offs;
700 size_t size = EXT4_XATTR_SIZE(
701 le32_to_cpu(s->here->e_value_size));
702
703 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
704 /* The old and the new value have the same
705 size. Just replace. */
706 s->here->e_value_size =
707 cpu_to_le32(i->value_len);
708 if (i->value == EXT4_ZERO_XATTR_VALUE) {
709 memset(val, 0, size);
710 } else {
711 /* Clear pad bytes first. */
712 memset(val + size - EXT4_XATTR_PAD, 0,
713 EXT4_XATTR_PAD);
714 memcpy(val, i->value, i->value_len);
715 }
716 return 0;
717 }
718
719 /* Remove the old value. */
720 memmove(first_val + size, first_val, val - first_val);
721 memset(first_val, 0, size);
722 s->here->e_value_size = 0;
723 s->here->e_value_offs = 0;
724 min_offs += size;
725
726 /* Adjust all value offsets. */
727 last = s->first;
728 while (!IS_LAST_ENTRY(last)) {
729 size_t o = le16_to_cpu(last->e_value_offs);
730 if (last->e_value_size && o < offs)
731 last->e_value_offs =
732 cpu_to_le16(o + size);
733 last = EXT4_XATTR_NEXT(last);
734 }
735 }
736 if (!i->value) {
737 /* Remove the old name. */
738 size_t size = EXT4_XATTR_LEN(name_len);
739 last = ENTRY((void *)last - size);
740 memmove(s->here, (void *)s->here + size,
741 (void *)last - (void *)s->here + sizeof(__u32));
742 memset(last, 0, size);
743 }
744 }
745
746 if (i->value) {
747 /* Insert the new value. */
748 s->here->e_value_size = cpu_to_le32(i->value_len);
749 if (i->value_len) {
750 size_t size = EXT4_XATTR_SIZE(i->value_len);
751 void *val = s->base + min_offs - size;
752 s->here->e_value_offs = cpu_to_le16(min_offs - size);
753 if (i->value == EXT4_ZERO_XATTR_VALUE) {
754 memset(val, 0, size);
755 } else {
756 /* Clear the pad bytes first. */
757 memset(val + size - EXT4_XATTR_PAD, 0,
758 EXT4_XATTR_PAD);
759 memcpy(val, i->value, i->value_len);
760 }
761 }
762 }
763 return 0;
764 }
765
766 struct ext4_xattr_block_find {
767 struct ext4_xattr_search s;
768 struct buffer_head *bh;
769 };
770
771 static int
772 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
773 struct ext4_xattr_block_find *bs)
774 {
775 struct super_block *sb = inode->i_sb;
776 int error;
777
778 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
779 i->name_index, i->name, i->value, (long)i->value_len);
780
781 if (EXT4_I(inode)->i_file_acl) {
782 /* The inode already has an extended attribute block. */
783 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
784 error = -EIO;
785 if (!bs->bh)
786 goto cleanup;
787 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
788 atomic_read(&(bs->bh->b_count)),
789 le32_to_cpu(BHDR(bs->bh)->h_refcount));
790 if (ext4_xattr_check_block(inode, bs->bh)) {
791 EXT4_ERROR_INODE(inode, "bad block %llu",
792 EXT4_I(inode)->i_file_acl);
793 error = -EFSCORRUPTED;
794 goto cleanup;
795 }
796 /* Find the named attribute. */
797 bs->s.base = BHDR(bs->bh);
798 bs->s.first = BFIRST(bs->bh);
799 bs->s.end = bs->bh->b_data + bs->bh->b_size;
800 bs->s.here = bs->s.first;
801 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
802 i->name, bs->bh->b_size, 1);
803 if (error && error != -ENODATA)
804 goto cleanup;
805 bs->s.not_found = error;
806 }
807 error = 0;
808
809 cleanup:
810 return error;
811 }
812
813 static int
814 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
815 struct ext4_xattr_info *i,
816 struct ext4_xattr_block_find *bs)
817 {
818 struct super_block *sb = inode->i_sb;
819 struct buffer_head *new_bh = NULL;
820 struct ext4_xattr_search *s = &bs->s;
821 struct mb_cache_entry *ce = NULL;
822 int error = 0;
823 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
824
825 #define header(x) ((struct ext4_xattr_header *)(x))
826
827 if (i->value && i->value_len > sb->s_blocksize)
828 return -ENOSPC;
829 if (s->base) {
830 BUFFER_TRACE(bs->bh, "get_write_access");
831 error = ext4_journal_get_write_access(handle, bs->bh);
832 if (error)
833 goto cleanup;
834 lock_buffer(bs->bh);
835
836 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
837 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
838
839 /*
840 * This must happen under buffer lock for
841 * ext4_xattr_block_set() to reliably detect modified
842 * block
843 */
844 mb_cache_entry_delete_block(ext4_mb_cache, hash,
845 bs->bh->b_blocknr);
846 ea_bdebug(bs->bh, "modifying in-place");
847 error = ext4_xattr_set_entry(i, s);
848 if (!error) {
849 if (!IS_LAST_ENTRY(s->first))
850 ext4_xattr_rehash(header(s->base),
851 s->here);
852 ext4_xattr_cache_insert(ext4_mb_cache,
853 bs->bh);
854 }
855 unlock_buffer(bs->bh);
856 if (error == -EFSCORRUPTED)
857 goto bad_block;
858 if (!error)
859 error = ext4_handle_dirty_xattr_block(handle,
860 inode,
861 bs->bh);
862 if (error)
863 goto cleanup;
864 goto inserted;
865 } else {
866 int offset = (char *)s->here - bs->bh->b_data;
867
868 unlock_buffer(bs->bh);
869 ea_bdebug(bs->bh, "cloning");
870 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
871 error = -ENOMEM;
872 if (s->base == NULL)
873 goto cleanup;
874 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
875 s->first = ENTRY(header(s->base)+1);
876 header(s->base)->h_refcount = cpu_to_le32(1);
877 s->here = ENTRY(s->base + offset);
878 s->end = s->base + bs->bh->b_size;
879 }
880 } else {
881 /* Allocate a buffer where we construct the new block. */
882 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
883 /* assert(header == s->base) */
884 error = -ENOMEM;
885 if (s->base == NULL)
886 goto cleanup;
887 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
888 header(s->base)->h_blocks = cpu_to_le32(1);
889 header(s->base)->h_refcount = cpu_to_le32(1);
890 s->first = ENTRY(header(s->base)+1);
891 s->here = ENTRY(header(s->base)+1);
892 s->end = s->base + sb->s_blocksize;
893 }
894
895 error = ext4_xattr_set_entry(i, s);
896 if (error == -EFSCORRUPTED)
897 goto bad_block;
898 if (error)
899 goto cleanup;
900 if (!IS_LAST_ENTRY(s->first))
901 ext4_xattr_rehash(header(s->base), s->here);
902
903 inserted:
904 if (!IS_LAST_ENTRY(s->first)) {
905 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
906 if (new_bh) {
907 /* We found an identical block in the cache. */
908 if (new_bh == bs->bh)
909 ea_bdebug(new_bh, "keeping");
910 else {
911 u32 ref;
912
913 /* The old block is released after updating
914 the inode. */
915 error = dquot_alloc_block(inode,
916 EXT4_C2B(EXT4_SB(sb), 1));
917 if (error)
918 goto cleanup;
919 BUFFER_TRACE(new_bh, "get_write_access");
920 error = ext4_journal_get_write_access(handle,
921 new_bh);
922 if (error)
923 goto cleanup_dquot;
924 lock_buffer(new_bh);
925 /*
926 * We have to be careful about races with
927 * freeing, rehashing or adding references to
928 * xattr block. Once we hold buffer lock xattr
929 * block's state is stable so we can check
930 * whether the block got freed / rehashed or
931 * not. Since we unhash mbcache entry under
932 * buffer lock when freeing / rehashing xattr
933 * block, checking whether entry is still
934 * hashed is reliable. Same rules hold for
935 * e_reusable handling.
936 */
937 if (hlist_bl_unhashed(&ce->e_hash_list) ||
938 !ce->e_reusable) {
939 /*
940 * Undo everything and check mbcache
941 * again.
942 */
943 unlock_buffer(new_bh);
944 dquot_free_block(inode,
945 EXT4_C2B(EXT4_SB(sb),
946 1));
947 brelse(new_bh);
948 mb_cache_entry_put(ext4_mb_cache, ce);
949 ce = NULL;
950 new_bh = NULL;
951 goto inserted;
952 }
953 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
954 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
955 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
956 ce->e_reusable = 0;
957 ea_bdebug(new_bh, "reusing; refcount now=%d",
958 ref);
959 unlock_buffer(new_bh);
960 error = ext4_handle_dirty_xattr_block(handle,
961 inode,
962 new_bh);
963 if (error)
964 goto cleanup_dquot;
965 }
966 mb_cache_entry_touch(ext4_mb_cache, ce);
967 mb_cache_entry_put(ext4_mb_cache, ce);
968 ce = NULL;
969 } else if (bs->bh && s->base == bs->bh->b_data) {
970 /* We were modifying this block in-place. */
971 ea_bdebug(bs->bh, "keeping this block");
972 new_bh = bs->bh;
973 get_bh(new_bh);
974 } else {
975 /* We need to allocate a new block */
976 ext4_fsblk_t goal, block;
977
978 goal = ext4_group_first_block_no(sb,
979 EXT4_I(inode)->i_block_group);
980
981 /* non-extent files can't have physical blocks past 2^32 */
982 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
983 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
984
985 block = ext4_new_meta_blocks(handle, inode, goal, 0,
986 NULL, &error);
987 if (error)
988 goto cleanup;
989
990 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
991 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
992
993 ea_idebug(inode, "creating block %llu",
994 (unsigned long long)block);
995
996 new_bh = sb_getblk(sb, block);
997 if (unlikely(!new_bh)) {
998 error = -ENOMEM;
999 getblk_failed:
1000 ext4_free_blocks(handle, inode, NULL, block, 1,
1001 EXT4_FREE_BLOCKS_METADATA);
1002 goto cleanup;
1003 }
1004 lock_buffer(new_bh);
1005 error = ext4_journal_get_create_access(handle, new_bh);
1006 if (error) {
1007 unlock_buffer(new_bh);
1008 error = -EIO;
1009 goto getblk_failed;
1010 }
1011 memcpy(new_bh->b_data, s->base, new_bh->b_size);
1012 set_buffer_uptodate(new_bh);
1013 unlock_buffer(new_bh);
1014 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1015 error = ext4_handle_dirty_xattr_block(handle,
1016 inode, new_bh);
1017 if (error)
1018 goto cleanup;
1019 }
1020 }
1021
1022 /* Update the inode. */
1023 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1024
1025 /* Drop the previous xattr block. */
1026 if (bs->bh && bs->bh != new_bh)
1027 ext4_xattr_release_block(handle, inode, bs->bh);
1028 error = 0;
1029
1030 cleanup:
1031 if (ce)
1032 mb_cache_entry_put(ext4_mb_cache, ce);
1033 brelse(new_bh);
1034 if (!(bs->bh && s->base == bs->bh->b_data))
1035 kfree(s->base);
1036
1037 return error;
1038
1039 cleanup_dquot:
1040 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1041 goto cleanup;
1042
1043 bad_block:
1044 EXT4_ERROR_INODE(inode, "bad block %llu",
1045 EXT4_I(inode)->i_file_acl);
1046 goto cleanup;
1047
1048 #undef header
1049 }
1050
1051 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
1052 struct ext4_xattr_ibody_find *is)
1053 {
1054 struct ext4_xattr_ibody_header *header;
1055 struct ext4_inode *raw_inode;
1056 int error;
1057
1058 if (EXT4_I(inode)->i_extra_isize == 0)
1059 return 0;
1060 raw_inode = ext4_raw_inode(&is->iloc);
1061 header = IHDR(inode, raw_inode);
1062 is->s.base = is->s.first = IFIRST(header);
1063 is->s.here = is->s.first;
1064 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1065 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1066 error = xattr_check_inode(inode, header, is->s.end);
1067 if (error)
1068 return error;
1069 /* Find the named attribute. */
1070 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1071 i->name, is->s.end -
1072 (void *)is->s.base, 0);
1073 if (error && error != -ENODATA)
1074 return error;
1075 is->s.not_found = error;
1076 }
1077 return 0;
1078 }
1079
1080 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1081 struct ext4_xattr_info *i,
1082 struct ext4_xattr_ibody_find *is)
1083 {
1084 struct ext4_xattr_ibody_header *header;
1085 struct ext4_xattr_search *s = &is->s;
1086 int error;
1087
1088 if (EXT4_I(inode)->i_extra_isize == 0)
1089 return -ENOSPC;
1090 error = ext4_xattr_set_entry(i, s);
1091 if (error) {
1092 if (error == -ENOSPC &&
1093 ext4_has_inline_data(inode)) {
1094 error = ext4_try_to_evict_inline_data(handle, inode,
1095 EXT4_XATTR_LEN(strlen(i->name) +
1096 EXT4_XATTR_SIZE(i->value_len)));
1097 if (error)
1098 return error;
1099 error = ext4_xattr_ibody_find(inode, i, is);
1100 if (error)
1101 return error;
1102 error = ext4_xattr_set_entry(i, s);
1103 }
1104 if (error)
1105 return error;
1106 }
1107 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1108 if (!IS_LAST_ENTRY(s->first)) {
1109 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1110 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1111 } else {
1112 header->h_magic = cpu_to_le32(0);
1113 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1114 }
1115 return 0;
1116 }
1117
1118 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1119 struct ext4_xattr_info *i,
1120 struct ext4_xattr_ibody_find *is)
1121 {
1122 struct ext4_xattr_ibody_header *header;
1123 struct ext4_xattr_search *s = &is->s;
1124 int error;
1125
1126 if (EXT4_I(inode)->i_extra_isize == 0)
1127 return -ENOSPC;
1128 error = ext4_xattr_set_entry(i, s);
1129 if (error)
1130 return error;
1131 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1132 if (!IS_LAST_ENTRY(s->first)) {
1133 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1134 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1135 } else {
1136 header->h_magic = cpu_to_le32(0);
1137 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1138 }
1139 return 0;
1140 }
1141
1142 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
1143 struct ext4_xattr_info *i)
1144 {
1145 void *value;
1146
1147 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
1148 return 0;
1149 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
1150 return !memcmp(value, i->value, i->value_len);
1151 }
1152
1153 /*
1154 * ext4_xattr_set_handle()
1155 *
1156 * Create, replace or remove an extended attribute for this inode. Value
1157 * is NULL to remove an existing extended attribute, and non-NULL to
1158 * either replace an existing extended attribute, or create a new extended
1159 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1160 * specify that an extended attribute must exist and must not exist
1161 * previous to the call, respectively.
1162 *
1163 * Returns 0, or a negative error number on failure.
1164 */
1165 int
1166 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1167 const char *name, const void *value, size_t value_len,
1168 int flags)
1169 {
1170 struct ext4_xattr_info i = {
1171 .name_index = name_index,
1172 .name = name,
1173 .value = value,
1174 .value_len = value_len,
1175
1176 };
1177 struct ext4_xattr_ibody_find is = {
1178 .s = { .not_found = -ENODATA, },
1179 };
1180 struct ext4_xattr_block_find bs = {
1181 .s = { .not_found = -ENODATA, },
1182 };
1183 unsigned long no_expand;
1184 int error;
1185
1186 if (!name)
1187 return -EINVAL;
1188 if (strlen(name) > 255)
1189 return -ERANGE;
1190 down_write(&EXT4_I(inode)->xattr_sem);
1191 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1192 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1193
1194 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1195 if (error)
1196 goto cleanup;
1197
1198 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1199 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1200 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1201 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1202 }
1203
1204 error = ext4_xattr_ibody_find(inode, &i, &is);
1205 if (error)
1206 goto cleanup;
1207 if (is.s.not_found)
1208 error = ext4_xattr_block_find(inode, &i, &bs);
1209 if (error)
1210 goto cleanup;
1211 if (is.s.not_found && bs.s.not_found) {
1212 error = -ENODATA;
1213 if (flags & XATTR_REPLACE)
1214 goto cleanup;
1215 error = 0;
1216 if (!value)
1217 goto cleanup;
1218 } else {
1219 error = -EEXIST;
1220 if (flags & XATTR_CREATE)
1221 goto cleanup;
1222 }
1223 if (!value) {
1224 if (!is.s.not_found)
1225 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1226 else if (!bs.s.not_found)
1227 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1228 } else {
1229 error = 0;
1230 /* Xattr value did not change? Save us some work and bail out */
1231 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
1232 goto cleanup;
1233 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
1234 goto cleanup;
1235
1236 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1237 if (!error && !bs.s.not_found) {
1238 i.value = NULL;
1239 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1240 } else if (error == -ENOSPC) {
1241 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1242 error = ext4_xattr_block_find(inode, &i, &bs);
1243 if (error)
1244 goto cleanup;
1245 }
1246 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1247 if (error)
1248 goto cleanup;
1249 if (!is.s.not_found) {
1250 i.value = NULL;
1251 error = ext4_xattr_ibody_set(handle, inode, &i,
1252 &is);
1253 }
1254 }
1255 }
1256 if (!error) {
1257 ext4_xattr_update_super_block(handle, inode->i_sb);
1258 inode->i_ctime = ext4_current_time(inode);
1259 if (!value)
1260 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1261 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1262 /*
1263 * The bh is consumed by ext4_mark_iloc_dirty, even with
1264 * error != 0.
1265 */
1266 is.iloc.bh = NULL;
1267 if (IS_SYNC(inode))
1268 ext4_handle_sync(handle);
1269 }
1270
1271 cleanup:
1272 brelse(is.iloc.bh);
1273 brelse(bs.bh);
1274 if (no_expand == 0)
1275 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1276 up_write(&EXT4_I(inode)->xattr_sem);
1277 return error;
1278 }
1279
1280 /*
1281 * ext4_xattr_set()
1282 *
1283 * Like ext4_xattr_set_handle, but start from an inode. This extended
1284 * attribute modification is a filesystem transaction by itself.
1285 *
1286 * Returns 0, or a negative error number on failure.
1287 */
1288 int
1289 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1290 const void *value, size_t value_len, int flags)
1291 {
1292 handle_t *handle;
1293 int error, retries = 0;
1294 int credits = ext4_jbd2_credits_xattr(inode);
1295
1296 retry:
1297 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1298 if (IS_ERR(handle)) {
1299 error = PTR_ERR(handle);
1300 } else {
1301 int error2;
1302
1303 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1304 value, value_len, flags);
1305 error2 = ext4_journal_stop(handle);
1306 if (error == -ENOSPC &&
1307 ext4_should_retry_alloc(inode->i_sb, &retries))
1308 goto retry;
1309 if (error == 0)
1310 error = error2;
1311 }
1312
1313 return error;
1314 }
1315
1316 /*
1317 * Shift the EA entries in the inode to create space for the increased
1318 * i_extra_isize.
1319 */
1320 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1321 int value_offs_shift, void *to,
1322 void *from, size_t n)
1323 {
1324 struct ext4_xattr_entry *last = entry;
1325 int new_offs;
1326
1327 /* We always shift xattr headers further thus offsets get lower */
1328 BUG_ON(value_offs_shift > 0);
1329
1330 /* Adjust the value offsets of the entries */
1331 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1332 if (last->e_value_size) {
1333 new_offs = le16_to_cpu(last->e_value_offs) +
1334 value_offs_shift;
1335 last->e_value_offs = cpu_to_le16(new_offs);
1336 }
1337 }
1338 /* Shift the entries by n bytes */
1339 memmove(to, from, n);
1340 }
1341
1342 /*
1343 * Move xattr pointed to by 'entry' from inode into external xattr block
1344 */
1345 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
1346 struct ext4_inode *raw_inode,
1347 struct ext4_xattr_entry *entry)
1348 {
1349 struct ext4_xattr_ibody_find *is = NULL;
1350 struct ext4_xattr_block_find *bs = NULL;
1351 char *buffer = NULL, *b_entry_name = NULL;
1352 size_t value_offs, value_size;
1353 struct ext4_xattr_info i = {
1354 .value = NULL,
1355 .value_len = 0,
1356 .name_index = entry->e_name_index,
1357 };
1358 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1359 int error;
1360
1361 value_offs = le16_to_cpu(entry->e_value_offs);
1362 value_size = le32_to_cpu(entry->e_value_size);
1363
1364 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1365 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1366 buffer = kmalloc(value_size, GFP_NOFS);
1367 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1368 if (!is || !bs || !buffer || !b_entry_name) {
1369 error = -ENOMEM;
1370 goto out;
1371 }
1372
1373 is->s.not_found = -ENODATA;
1374 bs->s.not_found = -ENODATA;
1375 is->iloc.bh = NULL;
1376 bs->bh = NULL;
1377
1378 /* Save the entry name and the entry value */
1379 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
1380 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1381 b_entry_name[entry->e_name_len] = '\0';
1382 i.name = b_entry_name;
1383
1384 error = ext4_get_inode_loc(inode, &is->iloc);
1385 if (error)
1386 goto out;
1387
1388 error = ext4_xattr_ibody_find(inode, &i, is);
1389 if (error)
1390 goto out;
1391
1392 /* Remove the chosen entry from the inode */
1393 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1394 if (error)
1395 goto out;
1396
1397 i.name = b_entry_name;
1398 i.value = buffer;
1399 i.value_len = value_size;
1400 error = ext4_xattr_block_find(inode, &i, bs);
1401 if (error)
1402 goto out;
1403
1404 /* Add entry which was removed from the inode into the block */
1405 error = ext4_xattr_block_set(handle, inode, &i, bs);
1406 if (error)
1407 goto out;
1408 error = 0;
1409 out:
1410 kfree(b_entry_name);
1411 kfree(buffer);
1412 if (is)
1413 brelse(is->iloc.bh);
1414 kfree(is);
1415 kfree(bs);
1416
1417 return error;
1418 }
1419
1420 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
1421 struct ext4_inode *raw_inode,
1422 int isize_diff, size_t ifree,
1423 size_t bfree, int *total_ino)
1424 {
1425 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1426 struct ext4_xattr_entry *small_entry;
1427 struct ext4_xattr_entry *entry;
1428 struct ext4_xattr_entry *last;
1429 unsigned int entry_size; /* EA entry size */
1430 unsigned int total_size; /* EA entry size + value size */
1431 unsigned int min_total_size;
1432 int error;
1433
1434 while (isize_diff > ifree) {
1435 entry = NULL;
1436 small_entry = NULL;
1437 min_total_size = ~0U;
1438 last = IFIRST(header);
1439 /* Find the entry best suited to be pushed into EA block */
1440 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1441 total_size =
1442 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1443 EXT4_XATTR_LEN(last->e_name_len);
1444 if (total_size <= bfree &&
1445 total_size < min_total_size) {
1446 if (total_size + ifree < isize_diff) {
1447 small_entry = last;
1448 } else {
1449 entry = last;
1450 min_total_size = total_size;
1451 }
1452 }
1453 }
1454
1455 if (entry == NULL) {
1456 if (small_entry == NULL)
1457 return -ENOSPC;
1458 entry = small_entry;
1459 }
1460
1461 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1462 total_size = entry_size +
1463 EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
1464 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
1465 entry);
1466 if (error)
1467 return error;
1468
1469 *total_ino -= entry_size;
1470 ifree += total_size;
1471 bfree -= total_size;
1472 }
1473
1474 return 0;
1475 }
1476
1477 /*
1478 * Expand an inode by new_extra_isize bytes when EAs are present.
1479 * Returns 0 on success or negative error number on failure.
1480 */
1481 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1482 struct ext4_inode *raw_inode, handle_t *handle)
1483 {
1484 struct ext4_xattr_ibody_header *header;
1485 struct buffer_head *bh = NULL;
1486 size_t min_offs;
1487 size_t ifree, bfree;
1488 int total_ino;
1489 void *base, *end;
1490 int error = 0, tried_min_extra_isize = 0;
1491 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1492 int isize_diff; /* How much do we need to grow i_extra_isize */
1493
1494 down_write(&EXT4_I(inode)->xattr_sem);
1495 /*
1496 * Set EXT4_STATE_NO_EXPAND to avoid recursion when marking inode dirty
1497 */
1498 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1499 retry:
1500 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
1501 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
1502 goto out;
1503
1504 header = IHDR(inode, raw_inode);
1505
1506 /*
1507 * Check if enough free space is available in the inode to shift the
1508 * entries ahead by new_extra_isize.
1509 */
1510
1511 base = IFIRST(header);
1512 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1513 min_offs = end - base;
1514 total_ino = sizeof(struct ext4_xattr_ibody_header);
1515
1516 error = xattr_check_inode(inode, header, end);
1517 if (error)
1518 goto cleanup;
1519
1520 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
1521 if (ifree >= isize_diff)
1522 goto shift;
1523
1524 /*
1525 * Enough free space isn't available in the inode, check if
1526 * EA block can hold new_extra_isize bytes.
1527 */
1528 if (EXT4_I(inode)->i_file_acl) {
1529 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1530 error = -EIO;
1531 if (!bh)
1532 goto cleanup;
1533 if (ext4_xattr_check_block(inode, bh)) {
1534 EXT4_ERROR_INODE(inode, "bad block %llu",
1535 EXT4_I(inode)->i_file_acl);
1536 error = -EFSCORRUPTED;
1537 goto cleanup;
1538 }
1539 base = BHDR(bh);
1540 end = bh->b_data + bh->b_size;
1541 min_offs = end - base;
1542 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
1543 NULL);
1544 if (bfree + ifree < isize_diff) {
1545 if (!tried_min_extra_isize && s_min_extra_isize) {
1546 tried_min_extra_isize++;
1547 new_extra_isize = s_min_extra_isize;
1548 brelse(bh);
1549 goto retry;
1550 }
1551 error = -ENOSPC;
1552 goto cleanup;
1553 }
1554 } else {
1555 bfree = inode->i_sb->s_blocksize;
1556 }
1557
1558 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
1559 isize_diff, ifree, bfree,
1560 &total_ino);
1561 if (error) {
1562 if (error == -ENOSPC && !tried_min_extra_isize &&
1563 s_min_extra_isize) {
1564 tried_min_extra_isize++;
1565 new_extra_isize = s_min_extra_isize;
1566 brelse(bh);
1567 goto retry;
1568 }
1569 goto cleanup;
1570 }
1571 shift:
1572 /* Adjust the offsets and shift the remaining entries ahead */
1573 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
1574 - new_extra_isize, (void *)raw_inode +
1575 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1576 (void *)header, total_ino);
1577 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1578 brelse(bh);
1579 out:
1580 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1581 up_write(&EXT4_I(inode)->xattr_sem);
1582 return 0;
1583
1584 cleanup:
1585 brelse(bh);
1586 /*
1587 * We deliberately leave EXT4_STATE_NO_EXPAND set here since inode
1588 * size expansion failed.
1589 */
1590 up_write(&EXT4_I(inode)->xattr_sem);
1591 return error;
1592 }
1593
1594
1595
1596 /*
1597 * ext4_xattr_delete_inode()
1598 *
1599 * Free extended attribute resources associated with this inode. This
1600 * is called immediately before an inode is freed. We have exclusive
1601 * access to the inode.
1602 */
1603 void
1604 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1605 {
1606 struct buffer_head *bh = NULL;
1607
1608 if (!EXT4_I(inode)->i_file_acl)
1609 goto cleanup;
1610 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1611 if (!bh) {
1612 EXT4_ERROR_INODE(inode, "block %llu read error",
1613 EXT4_I(inode)->i_file_acl);
1614 goto cleanup;
1615 }
1616 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1617 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1618 EXT4_ERROR_INODE(inode, "bad block %llu",
1619 EXT4_I(inode)->i_file_acl);
1620 goto cleanup;
1621 }
1622 ext4_xattr_release_block(handle, inode, bh);
1623 EXT4_I(inode)->i_file_acl = 0;
1624
1625 cleanup:
1626 brelse(bh);
1627 }
1628
1629 /*
1630 * ext4_xattr_cache_insert()
1631 *
1632 * Create a new entry in the extended attribute cache, and insert
1633 * it unless such an entry is already in the cache.
1634 *
1635 * Returns 0, or a negative error number on failure.
1636 */
1637 static void
1638 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1639 {
1640 struct ext4_xattr_header *header = BHDR(bh);
1641 __u32 hash = le32_to_cpu(header->h_hash);
1642 int reusable = le32_to_cpu(header->h_refcount) <
1643 EXT4_XATTR_REFCOUNT_MAX;
1644 int error;
1645
1646 error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1647 bh->b_blocknr, reusable);
1648 if (error) {
1649 if (error == -EBUSY)
1650 ea_bdebug(bh, "already in cache");
1651 } else
1652 ea_bdebug(bh, "inserting [%x]", (int)hash);
1653 }
1654
1655 /*
1656 * ext4_xattr_cmp()
1657 *
1658 * Compare two extended attribute blocks for equality.
1659 *
1660 * Returns 0 if the blocks are equal, 1 if they differ, and
1661 * a negative error number on errors.
1662 */
1663 static int
1664 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1665 struct ext4_xattr_header *header2)
1666 {
1667 struct ext4_xattr_entry *entry1, *entry2;
1668
1669 entry1 = ENTRY(header1+1);
1670 entry2 = ENTRY(header2+1);
1671 while (!IS_LAST_ENTRY(entry1)) {
1672 if (IS_LAST_ENTRY(entry2))
1673 return 1;
1674 if (entry1->e_hash != entry2->e_hash ||
1675 entry1->e_name_index != entry2->e_name_index ||
1676 entry1->e_name_len != entry2->e_name_len ||
1677 entry1->e_value_size != entry2->e_value_size ||
1678 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1679 return 1;
1680 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1681 return -EFSCORRUPTED;
1682 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1683 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1684 le32_to_cpu(entry1->e_value_size)))
1685 return 1;
1686
1687 entry1 = EXT4_XATTR_NEXT(entry1);
1688 entry2 = EXT4_XATTR_NEXT(entry2);
1689 }
1690 if (!IS_LAST_ENTRY(entry2))
1691 return 1;
1692 return 0;
1693 }
1694
1695 /*
1696 * ext4_xattr_cache_find()
1697 *
1698 * Find an identical extended attribute block.
1699 *
1700 * Returns a pointer to the block found, or NULL if such a block was
1701 * not found or an error occurred.
1702 */
1703 static struct buffer_head *
1704 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1705 struct mb_cache_entry **pce)
1706 {
1707 __u32 hash = le32_to_cpu(header->h_hash);
1708 struct mb_cache_entry *ce;
1709 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1710
1711 if (!header->h_hash)
1712 return NULL; /* never share */
1713 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1714 ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1715 while (ce) {
1716 struct buffer_head *bh;
1717
1718 bh = sb_bread(inode->i_sb, ce->e_block);
1719 if (!bh) {
1720 EXT4_ERROR_INODE(inode, "block %lu read error",
1721 (unsigned long) ce->e_block);
1722 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1723 *pce = ce;
1724 return bh;
1725 }
1726 brelse(bh);
1727 ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1728 }
1729 return NULL;
1730 }
1731
1732 #define NAME_HASH_SHIFT 5
1733 #define VALUE_HASH_SHIFT 16
1734
1735 /*
1736 * ext4_xattr_hash_entry()
1737 *
1738 * Compute the hash of an extended attribute.
1739 */
1740 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1741 struct ext4_xattr_entry *entry)
1742 {
1743 __u32 hash = 0;
1744 char *name = entry->e_name;
1745 int n;
1746
1747 for (n = 0; n < entry->e_name_len; n++) {
1748 hash = (hash << NAME_HASH_SHIFT) ^
1749 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1750 *name++;
1751 }
1752
1753 if (entry->e_value_size != 0) {
1754 __le32 *value = (__le32 *)((char *)header +
1755 le16_to_cpu(entry->e_value_offs));
1756 for (n = (le32_to_cpu(entry->e_value_size) +
1757 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1758 hash = (hash << VALUE_HASH_SHIFT) ^
1759 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1760 le32_to_cpu(*value++);
1761 }
1762 }
1763 entry->e_hash = cpu_to_le32(hash);
1764 }
1765
1766 #undef NAME_HASH_SHIFT
1767 #undef VALUE_HASH_SHIFT
1768
1769 #define BLOCK_HASH_SHIFT 16
1770
1771 /*
1772 * ext4_xattr_rehash()
1773 *
1774 * Re-compute the extended attribute hash value after an entry has changed.
1775 */
1776 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1777 struct ext4_xattr_entry *entry)
1778 {
1779 struct ext4_xattr_entry *here;
1780 __u32 hash = 0;
1781
1782 ext4_xattr_hash_entry(header, entry);
1783 here = ENTRY(header+1);
1784 while (!IS_LAST_ENTRY(here)) {
1785 if (!here->e_hash) {
1786 /* Block is not shared if an entry's hash value == 0 */
1787 hash = 0;
1788 break;
1789 }
1790 hash = (hash << BLOCK_HASH_SHIFT) ^
1791 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1792 le32_to_cpu(here->e_hash);
1793 here = EXT4_XATTR_NEXT(here);
1794 }
1795 header->h_hash = cpu_to_le32(hash);
1796 }
1797
1798 #undef BLOCK_HASH_SHIFT
1799
1800 #define HASH_BUCKET_BITS 10
1801
1802 struct mb_cache *
1803 ext4_xattr_create_cache(void)
1804 {
1805 return mb_cache_create(HASH_BUCKET_BITS);
1806 }
1807
1808 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1809 {
1810 if (cache)
1811 mb_cache_destroy(cache);
1812 }
1813
Linux kernel - Deliverables
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