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[mirror_ubuntu-bionic-kernel.git] / fs / ext4 / xattr.c
1 /*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16 /*
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53 #include <linux/init.h>
54 #include <linux/fs.h>
55 #include <linux/slab.h>
56 #include <linux/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, fmt, ...) \
65 printk(KERN_DEBUG "inode %s:%lu: " fmt "\n", \
66 inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
67 # define ea_bdebug(bh, fmt, ...) \
68 printk(KERN_DEBUG "block %pg:%lu: " fmt "\n", \
69 bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
70 #else
71 # define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
72 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
73 #endif
74
75 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
76 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
77 struct ext4_xattr_header *,
78 struct mb_cache_entry **);
79 static void ext4_xattr_rehash(struct ext4_xattr_header *,
80 struct ext4_xattr_entry *);
81 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
82 size_t buffer_size);
83
84 static const struct xattr_handler *ext4_xattr_handler_map[] = {
85 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
86 #ifdef CONFIG_EXT4_FS_POSIX_ACL
87 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
88 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
89 #endif
90 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
91 #ifdef CONFIG_EXT4_FS_SECURITY
92 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
93 #endif
94 };
95
96 const struct xattr_handler *ext4_xattr_handlers[] = {
97 &ext4_xattr_user_handler,
98 &ext4_xattr_trusted_handler,
99 #ifdef CONFIG_EXT4_FS_POSIX_ACL
100 &posix_acl_access_xattr_handler,
101 &posix_acl_default_xattr_handler,
102 #endif
103 #ifdef CONFIG_EXT4_FS_SECURITY
104 &ext4_xattr_security_handler,
105 #endif
106 NULL
107 };
108
109 #define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \
110 inode->i_sb->s_fs_info)->s_mb_cache)
111
112 static __le32 ext4_xattr_block_csum(struct inode *inode,
113 sector_t block_nr,
114 struct ext4_xattr_header *hdr)
115 {
116 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
117 __u32 csum;
118 __le64 dsk_block_nr = cpu_to_le64(block_nr);
119 __u32 dummy_csum = 0;
120 int offset = offsetof(struct ext4_xattr_header, h_checksum);
121
122 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
123 sizeof(dsk_block_nr));
124 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
125 csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
126 offset += sizeof(dummy_csum);
127 csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
128 EXT4_BLOCK_SIZE(inode->i_sb) - offset);
129
130 return cpu_to_le32(csum);
131 }
132
133 static int ext4_xattr_block_csum_verify(struct inode *inode,
134 sector_t block_nr,
135 struct ext4_xattr_header *hdr)
136 {
137 if (ext4_has_metadata_csum(inode->i_sb) &&
138 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
139 return 0;
140 return 1;
141 }
142
143 static void ext4_xattr_block_csum_set(struct inode *inode,
144 sector_t block_nr,
145 struct ext4_xattr_header *hdr)
146 {
147 if (!ext4_has_metadata_csum(inode->i_sb))
148 return;
149
150 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
151 }
152
153 static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
154 struct inode *inode,
155 struct buffer_head *bh)
156 {
157 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
158 return ext4_handle_dirty_metadata(handle, inode, bh);
159 }
160
161 static inline const struct xattr_handler *
162 ext4_xattr_handler(int name_index)
163 {
164 const struct xattr_handler *handler = NULL;
165
166 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
167 handler = ext4_xattr_handler_map[name_index];
168 return handler;
169 }
170
171 /*
172 * Inode operation listxattr()
173 *
174 * d_inode(dentry)->i_mutex: don't care
175 */
176 ssize_t
177 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
178 {
179 return ext4_xattr_list(dentry, buffer, size);
180 }
181
182 static int
183 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
184 void *value_start)
185 {
186 struct ext4_xattr_entry *e = entry;
187
188 /* Find the end of the names list */
189 while (!IS_LAST_ENTRY(e)) {
190 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
191 if ((void *)next >= end)
192 return -EFSCORRUPTED;
193 e = next;
194 }
195
196 /* Check the values */
197 while (!IS_LAST_ENTRY(entry)) {
198 if (entry->e_value_block != 0)
199 return -EFSCORRUPTED;
200 if (entry->e_value_size != 0) {
201 u16 offs = le16_to_cpu(entry->e_value_offs);
202 u32 size = le32_to_cpu(entry->e_value_size);
203 void *value;
204
205 /*
206 * The value cannot overlap the names, and the value
207 * with padding cannot extend beyond 'end'. Check both
208 * the padded and unpadded sizes, since the size may
209 * overflow to 0 when adding padding.
210 */
211 if (offs > end - value_start)
212 return -EFSCORRUPTED;
213 value = value_start + offs;
214 if (value < (void *)e + sizeof(u32) ||
215 size > end - value ||
216 EXT4_XATTR_SIZE(size) > end - value)
217 return -EFSCORRUPTED;
218 }
219 entry = EXT4_XATTR_NEXT(entry);
220 }
221
222 return 0;
223 }
224
225 static inline int
226 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
227 {
228 int error;
229
230 if (buffer_verified(bh))
231 return 0;
232
233 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
234 BHDR(bh)->h_blocks != cpu_to_le32(1))
235 return -EFSCORRUPTED;
236 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
237 return -EFSBADCRC;
238 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
239 bh->b_data);
240 if (!error)
241 set_buffer_verified(bh);
242 return error;
243 }
244
245 static int
246 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
247 void *end, const char *function, unsigned int line)
248 {
249 int error = -EFSCORRUPTED;
250
251 if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
252 (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
253 goto errout;
254 error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header));
255 errout:
256 if (error)
257 __ext4_error_inode(inode, function, line, 0,
258 "corrupted in-inode xattr");
259 return error;
260 }
261
262 #define xattr_check_inode(inode, header, end) \
263 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
264
265 static inline int
266 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
267 {
268 size_t value_size = le32_to_cpu(entry->e_value_size);
269
270 if (entry->e_value_block != 0 || value_size > size ||
271 le16_to_cpu(entry->e_value_offs) + value_size > size)
272 return -EFSCORRUPTED;
273 return 0;
274 }
275
276 static int
277 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
278 const char *name, size_t size, int sorted)
279 {
280 struct ext4_xattr_entry *entry;
281 size_t name_len;
282 int cmp = 1;
283
284 if (name == NULL)
285 return -EINVAL;
286 name_len = strlen(name);
287 entry = *pentry;
288 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
289 cmp = name_index - entry->e_name_index;
290 if (!cmp)
291 cmp = name_len - entry->e_name_len;
292 if (!cmp)
293 cmp = memcmp(name, entry->e_name, name_len);
294 if (cmp <= 0 && (sorted || cmp == 0))
295 break;
296 }
297 *pentry = entry;
298 if (!cmp && ext4_xattr_check_entry(entry, size))
299 return -EFSCORRUPTED;
300 return cmp ? -ENODATA : 0;
301 }
302
303 static int
304 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
305 void *buffer, size_t buffer_size)
306 {
307 struct buffer_head *bh = NULL;
308 struct ext4_xattr_entry *entry;
309 size_t size;
310 int error;
311 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
312
313 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
314 name_index, name, buffer, (long)buffer_size);
315
316 error = -ENODATA;
317 if (!EXT4_I(inode)->i_file_acl)
318 goto cleanup;
319 ea_idebug(inode, "reading block %llu",
320 (unsigned long long)EXT4_I(inode)->i_file_acl);
321 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
322 if (!bh)
323 goto cleanup;
324 ea_bdebug(bh, "b_count=%d, refcount=%d",
325 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
326 if (ext4_xattr_check_block(inode, bh)) {
327 bad_block:
328 EXT4_ERROR_INODE(inode, "bad block %llu",
329 EXT4_I(inode)->i_file_acl);
330 error = -EFSCORRUPTED;
331 goto cleanup;
332 }
333 ext4_xattr_cache_insert(ext4_mb_cache, bh);
334 entry = BFIRST(bh);
335 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
336 if (error == -EFSCORRUPTED)
337 goto bad_block;
338 if (error)
339 goto cleanup;
340 size = le32_to_cpu(entry->e_value_size);
341 if (buffer) {
342 error = -ERANGE;
343 if (size > buffer_size)
344 goto cleanup;
345 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
346 size);
347 }
348 error = size;
349
350 cleanup:
351 brelse(bh);
352 return error;
353 }
354
355 int
356 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
357 void *buffer, size_t buffer_size)
358 {
359 struct ext4_xattr_ibody_header *header;
360 struct ext4_xattr_entry *entry;
361 struct ext4_inode *raw_inode;
362 struct ext4_iloc iloc;
363 size_t size;
364 void *end;
365 int error;
366
367 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
368 return -ENODATA;
369 error = ext4_get_inode_loc(inode, &iloc);
370 if (error)
371 return error;
372 raw_inode = ext4_raw_inode(&iloc);
373 header = IHDR(inode, raw_inode);
374 entry = IFIRST(header);
375 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
376 error = xattr_check_inode(inode, header, end);
377 if (error)
378 goto cleanup;
379 error = ext4_xattr_find_entry(&entry, name_index, name,
380 end - (void *)entry, 0);
381 if (error)
382 goto cleanup;
383 size = le32_to_cpu(entry->e_value_size);
384 if (buffer) {
385 error = -ERANGE;
386 if (size > buffer_size)
387 goto cleanup;
388 memcpy(buffer, (void *)IFIRST(header) +
389 le16_to_cpu(entry->e_value_offs), size);
390 }
391 error = size;
392
393 cleanup:
394 brelse(iloc.bh);
395 return error;
396 }
397
398 /*
399 * ext4_xattr_get()
400 *
401 * Copy an extended attribute into the buffer
402 * provided, or compute the buffer size required.
403 * Buffer is NULL to compute the size of the buffer required.
404 *
405 * Returns a negative error number on failure, or the number of bytes
406 * used / required on success.
407 */
408 int
409 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
410 void *buffer, size_t buffer_size)
411 {
412 int error;
413
414 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
415 return -EIO;
416
417 if (strlen(name) > 255)
418 return -ERANGE;
419
420 down_read(&EXT4_I(inode)->xattr_sem);
421 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
422 buffer_size);
423 if (error == -ENODATA)
424 error = ext4_xattr_block_get(inode, name_index, name, buffer,
425 buffer_size);
426 up_read(&EXT4_I(inode)->xattr_sem);
427 return error;
428 }
429
430 static int
431 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
432 char *buffer, size_t buffer_size)
433 {
434 size_t rest = buffer_size;
435
436 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
437 const struct xattr_handler *handler =
438 ext4_xattr_handler(entry->e_name_index);
439
440 if (handler && (!handler->list || handler->list(dentry))) {
441 const char *prefix = handler->prefix ?: handler->name;
442 size_t prefix_len = strlen(prefix);
443 size_t size = prefix_len + entry->e_name_len + 1;
444
445 if (buffer) {
446 if (size > rest)
447 return -ERANGE;
448 memcpy(buffer, prefix, prefix_len);
449 buffer += prefix_len;
450 memcpy(buffer, entry->e_name, entry->e_name_len);
451 buffer += entry->e_name_len;
452 *buffer++ = 0;
453 }
454 rest -= size;
455 }
456 }
457 return buffer_size - rest; /* total size */
458 }
459
460 static int
461 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
462 {
463 struct inode *inode = d_inode(dentry);
464 struct buffer_head *bh = NULL;
465 int error;
466 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
467
468 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
469 buffer, (long)buffer_size);
470
471 error = 0;
472 if (!EXT4_I(inode)->i_file_acl)
473 goto cleanup;
474 ea_idebug(inode, "reading block %llu",
475 (unsigned long long)EXT4_I(inode)->i_file_acl);
476 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
477 error = -EIO;
478 if (!bh)
479 goto cleanup;
480 ea_bdebug(bh, "b_count=%d, refcount=%d",
481 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
482 if (ext4_xattr_check_block(inode, bh)) {
483 EXT4_ERROR_INODE(inode, "bad block %llu",
484 EXT4_I(inode)->i_file_acl);
485 error = -EFSCORRUPTED;
486 goto cleanup;
487 }
488 ext4_xattr_cache_insert(ext4_mb_cache, bh);
489 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
490
491 cleanup:
492 brelse(bh);
493
494 return error;
495 }
496
497 static int
498 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
499 {
500 struct inode *inode = d_inode(dentry);
501 struct ext4_xattr_ibody_header *header;
502 struct ext4_inode *raw_inode;
503 struct ext4_iloc iloc;
504 void *end;
505 int error;
506
507 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
508 return 0;
509 error = ext4_get_inode_loc(inode, &iloc);
510 if (error)
511 return error;
512 raw_inode = ext4_raw_inode(&iloc);
513 header = IHDR(inode, raw_inode);
514 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
515 error = xattr_check_inode(inode, header, end);
516 if (error)
517 goto cleanup;
518 error = ext4_xattr_list_entries(dentry, IFIRST(header),
519 buffer, buffer_size);
520
521 cleanup:
522 brelse(iloc.bh);
523 return error;
524 }
525
526 /*
527 * ext4_xattr_list()
528 *
529 * Copy a list of attribute names into the buffer
530 * provided, or compute the buffer size required.
531 * Buffer is NULL to compute the size of the buffer required.
532 *
533 * Returns a negative error number on failure, or the number of bytes
534 * used / required on success.
535 */
536 static int
537 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
538 {
539 int ret, ret2;
540
541 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
542 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
543 if (ret < 0)
544 goto errout;
545 if (buffer) {
546 buffer += ret;
547 buffer_size -= ret;
548 }
549 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
550 if (ret < 0)
551 goto errout;
552 ret += ret2;
553 errout:
554 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
555 return ret;
556 }
557
558 /*
559 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
560 * not set, set it.
561 */
562 static void ext4_xattr_update_super_block(handle_t *handle,
563 struct super_block *sb)
564 {
565 if (ext4_has_feature_xattr(sb))
566 return;
567
568 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
569 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
570 ext4_set_feature_xattr(sb);
571 ext4_handle_dirty_super(handle, sb);
572 }
573 }
574
575 /*
576 * Release the xattr block BH: If the reference count is > 1, decrement it;
577 * otherwise free the block.
578 */
579 static void
580 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
581 struct buffer_head *bh)
582 {
583 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
584 u32 hash, ref;
585 int error = 0;
586
587 BUFFER_TRACE(bh, "get_write_access");
588 error = ext4_journal_get_write_access(handle, bh);
589 if (error)
590 goto out;
591
592 lock_buffer(bh);
593 hash = le32_to_cpu(BHDR(bh)->h_hash);
594 ref = le32_to_cpu(BHDR(bh)->h_refcount);
595 if (ref == 1) {
596 ea_bdebug(bh, "refcount now=0; freeing");
597 /*
598 * This must happen under buffer lock for
599 * ext4_xattr_block_set() to reliably detect freed block
600 */
601 mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
602 get_bh(bh);
603 unlock_buffer(bh);
604 ext4_free_blocks(handle, inode, bh, 0, 1,
605 EXT4_FREE_BLOCKS_METADATA |
606 EXT4_FREE_BLOCKS_FORGET);
607 } else {
608 ref--;
609 BHDR(bh)->h_refcount = cpu_to_le32(ref);
610 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
611 struct mb_cache_entry *ce;
612
613 ce = mb_cache_entry_get(ext4_mb_cache, hash,
614 bh->b_blocknr);
615 if (ce) {
616 ce->e_reusable = 1;
617 mb_cache_entry_put(ext4_mb_cache, ce);
618 }
619 }
620
621 /*
622 * Beware of this ugliness: Releasing of xattr block references
623 * from different inodes can race and so we have to protect
624 * from a race where someone else frees the block (and releases
625 * its journal_head) before we are done dirtying the buffer. In
626 * nojournal mode this race is harmless and we actually cannot
627 * call ext4_handle_dirty_xattr_block() with locked buffer as
628 * that function can call sync_dirty_buffer() so for that case
629 * we handle the dirtying after unlocking the buffer.
630 */
631 if (ext4_handle_valid(handle))
632 error = ext4_handle_dirty_xattr_block(handle, inode,
633 bh);
634 unlock_buffer(bh);
635 if (!ext4_handle_valid(handle))
636 error = ext4_handle_dirty_xattr_block(handle, inode,
637 bh);
638 if (IS_SYNC(inode))
639 ext4_handle_sync(handle);
640 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
641 ea_bdebug(bh, "refcount now=%d; releasing",
642 le32_to_cpu(BHDR(bh)->h_refcount));
643 }
644 out:
645 ext4_std_error(inode->i_sb, error);
646 return;
647 }
648
649 /*
650 * Find the available free space for EAs. This also returns the total number of
651 * bytes used by EA entries.
652 */
653 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
654 size_t *min_offs, void *base, int *total)
655 {
656 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
657 if (last->e_value_size) {
658 size_t offs = le16_to_cpu(last->e_value_offs);
659 if (offs < *min_offs)
660 *min_offs = offs;
661 }
662 if (total)
663 *total += EXT4_XATTR_LEN(last->e_name_len);
664 }
665 return (*min_offs - ((void *)last - base) - sizeof(__u32));
666 }
667
668 static int
669 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
670 {
671 struct ext4_xattr_entry *last;
672 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
673
674 /* Compute min_offs and last. */
675 last = s->first;
676 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
677 if (last->e_value_size) {
678 size_t offs = le16_to_cpu(last->e_value_offs);
679 if (offs < min_offs)
680 min_offs = offs;
681 }
682 }
683 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
684 if (!s->not_found) {
685 if (s->here->e_value_size) {
686 size_t size = le32_to_cpu(s->here->e_value_size);
687 free += EXT4_XATTR_SIZE(size);
688 }
689 free += EXT4_XATTR_LEN(name_len);
690 }
691 if (i->value) {
692 if (free < EXT4_XATTR_LEN(name_len) +
693 EXT4_XATTR_SIZE(i->value_len))
694 return -ENOSPC;
695 }
696
697 if (i->value && s->not_found) {
698 /* Insert the new name. */
699 size_t size = EXT4_XATTR_LEN(name_len);
700 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
701 memmove((void *)s->here + size, s->here, rest);
702 memset(s->here, 0, size);
703 s->here->e_name_index = i->name_index;
704 s->here->e_name_len = name_len;
705 memcpy(s->here->e_name, i->name, name_len);
706 } else {
707 if (s->here->e_value_size) {
708 void *first_val = s->base + min_offs;
709 size_t offs = le16_to_cpu(s->here->e_value_offs);
710 void *val = s->base + offs;
711 size_t size = EXT4_XATTR_SIZE(
712 le32_to_cpu(s->here->e_value_size));
713
714 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
715 /* The old and the new value have the same
716 size. Just replace. */
717 s->here->e_value_size =
718 cpu_to_le32(i->value_len);
719 if (i->value == EXT4_ZERO_XATTR_VALUE) {
720 memset(val, 0, size);
721 } else {
722 /* Clear pad bytes first. */
723 memset(val + size - EXT4_XATTR_PAD, 0,
724 EXT4_XATTR_PAD);
725 memcpy(val, i->value, i->value_len);
726 }
727 return 0;
728 }
729
730 /* Remove the old value. */
731 memmove(first_val + size, first_val, val - first_val);
732 memset(first_val, 0, size);
733 s->here->e_value_size = 0;
734 s->here->e_value_offs = 0;
735 min_offs += size;
736
737 /* Adjust all value offsets. */
738 last = s->first;
739 while (!IS_LAST_ENTRY(last)) {
740 size_t o = le16_to_cpu(last->e_value_offs);
741 if (last->e_value_size && o < offs)
742 last->e_value_offs =
743 cpu_to_le16(o + size);
744 last = EXT4_XATTR_NEXT(last);
745 }
746 }
747 if (!i->value) {
748 /* Remove the old name. */
749 size_t size = EXT4_XATTR_LEN(name_len);
750 last = ENTRY((void *)last - size);
751 memmove(s->here, (void *)s->here + size,
752 (void *)last - (void *)s->here + sizeof(__u32));
753 memset(last, 0, size);
754 }
755 }
756
757 if (i->value) {
758 /* Insert the new value. */
759 s->here->e_value_size = cpu_to_le32(i->value_len);
760 if (i->value_len) {
761 size_t size = EXT4_XATTR_SIZE(i->value_len);
762 void *val = s->base + min_offs - size;
763 s->here->e_value_offs = cpu_to_le16(min_offs - size);
764 if (i->value == EXT4_ZERO_XATTR_VALUE) {
765 memset(val, 0, size);
766 } else {
767 /* Clear the pad bytes first. */
768 memset(val + size - EXT4_XATTR_PAD, 0,
769 EXT4_XATTR_PAD);
770 memcpy(val, i->value, i->value_len);
771 }
772 }
773 }
774 return 0;
775 }
776
777 struct ext4_xattr_block_find {
778 struct ext4_xattr_search s;
779 struct buffer_head *bh;
780 };
781
782 static int
783 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
784 struct ext4_xattr_block_find *bs)
785 {
786 struct super_block *sb = inode->i_sb;
787 int error;
788
789 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
790 i->name_index, i->name, i->value, (long)i->value_len);
791
792 if (EXT4_I(inode)->i_file_acl) {
793 /* The inode already has an extended attribute block. */
794 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
795 error = -EIO;
796 if (!bs->bh)
797 goto cleanup;
798 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
799 atomic_read(&(bs->bh->b_count)),
800 le32_to_cpu(BHDR(bs->bh)->h_refcount));
801 if (ext4_xattr_check_block(inode, bs->bh)) {
802 EXT4_ERROR_INODE(inode, "bad block %llu",
803 EXT4_I(inode)->i_file_acl);
804 error = -EFSCORRUPTED;
805 goto cleanup;
806 }
807 /* Find the named attribute. */
808 bs->s.base = BHDR(bs->bh);
809 bs->s.first = BFIRST(bs->bh);
810 bs->s.end = bs->bh->b_data + bs->bh->b_size;
811 bs->s.here = bs->s.first;
812 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
813 i->name, bs->bh->b_size, 1);
814 if (error && error != -ENODATA)
815 goto cleanup;
816 bs->s.not_found = error;
817 }
818 error = 0;
819
820 cleanup:
821 return error;
822 }
823
824 static int
825 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
826 struct ext4_xattr_info *i,
827 struct ext4_xattr_block_find *bs)
828 {
829 struct super_block *sb = inode->i_sb;
830 struct buffer_head *new_bh = NULL;
831 struct ext4_xattr_search *s = &bs->s;
832 struct mb_cache_entry *ce = NULL;
833 int error = 0;
834 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
835
836 #define header(x) ((struct ext4_xattr_header *)(x))
837
838 if (i->value && i->value_len > sb->s_blocksize)
839 return -ENOSPC;
840 if (s->base) {
841 BUFFER_TRACE(bs->bh, "get_write_access");
842 error = ext4_journal_get_write_access(handle, bs->bh);
843 if (error)
844 goto cleanup;
845 lock_buffer(bs->bh);
846
847 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
848 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
849
850 /*
851 * This must happen under buffer lock for
852 * ext4_xattr_block_set() to reliably detect modified
853 * block
854 */
855 mb_cache_entry_delete_block(ext4_mb_cache, hash,
856 bs->bh->b_blocknr);
857 ea_bdebug(bs->bh, "modifying in-place");
858 error = ext4_xattr_set_entry(i, s);
859 if (!error) {
860 if (!IS_LAST_ENTRY(s->first))
861 ext4_xattr_rehash(header(s->base),
862 s->here);
863 ext4_xattr_cache_insert(ext4_mb_cache,
864 bs->bh);
865 }
866 unlock_buffer(bs->bh);
867 if (error == -EFSCORRUPTED)
868 goto bad_block;
869 if (!error)
870 error = ext4_handle_dirty_xattr_block(handle,
871 inode,
872 bs->bh);
873 if (error)
874 goto cleanup;
875 goto inserted;
876 } else {
877 int offset = (char *)s->here - bs->bh->b_data;
878
879 unlock_buffer(bs->bh);
880 ea_bdebug(bs->bh, "cloning");
881 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
882 error = -ENOMEM;
883 if (s->base == NULL)
884 goto cleanup;
885 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
886 s->first = ENTRY(header(s->base)+1);
887 header(s->base)->h_refcount = cpu_to_le32(1);
888 s->here = ENTRY(s->base + offset);
889 s->end = s->base + bs->bh->b_size;
890 }
891 } else {
892 /* Allocate a buffer where we construct the new block. */
893 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
894 /* assert(header == s->base) */
895 error = -ENOMEM;
896 if (s->base == NULL)
897 goto cleanup;
898 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
899 header(s->base)->h_blocks = cpu_to_le32(1);
900 header(s->base)->h_refcount = cpu_to_le32(1);
901 s->first = ENTRY(header(s->base)+1);
902 s->here = ENTRY(header(s->base)+1);
903 s->end = s->base + sb->s_blocksize;
904 }
905
906 error = ext4_xattr_set_entry(i, s);
907 if (error == -EFSCORRUPTED)
908 goto bad_block;
909 if (error)
910 goto cleanup;
911 if (!IS_LAST_ENTRY(s->first))
912 ext4_xattr_rehash(header(s->base), s->here);
913
914 inserted:
915 if (!IS_LAST_ENTRY(s->first)) {
916 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
917 if (new_bh) {
918 /* We found an identical block in the cache. */
919 if (new_bh == bs->bh)
920 ea_bdebug(new_bh, "keeping");
921 else {
922 u32 ref;
923
924 /* The old block is released after updating
925 the inode. */
926 error = dquot_alloc_block(inode,
927 EXT4_C2B(EXT4_SB(sb), 1));
928 if (error)
929 goto cleanup;
930 BUFFER_TRACE(new_bh, "get_write_access");
931 error = ext4_journal_get_write_access(handle,
932 new_bh);
933 if (error)
934 goto cleanup_dquot;
935 lock_buffer(new_bh);
936 /*
937 * We have to be careful about races with
938 * freeing, rehashing or adding references to
939 * xattr block. Once we hold buffer lock xattr
940 * block's state is stable so we can check
941 * whether the block got freed / rehashed or
942 * not. Since we unhash mbcache entry under
943 * buffer lock when freeing / rehashing xattr
944 * block, checking whether entry is still
945 * hashed is reliable. Same rules hold for
946 * e_reusable handling.
947 */
948 if (hlist_bl_unhashed(&ce->e_hash_list) ||
949 !ce->e_reusable) {
950 /*
951 * Undo everything and check mbcache
952 * again.
953 */
954 unlock_buffer(new_bh);
955 dquot_free_block(inode,
956 EXT4_C2B(EXT4_SB(sb),
957 1));
958 brelse(new_bh);
959 mb_cache_entry_put(ext4_mb_cache, ce);
960 ce = NULL;
961 new_bh = NULL;
962 goto inserted;
963 }
964 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
965 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
966 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
967 ce->e_reusable = 0;
968 ea_bdebug(new_bh, "reusing; refcount now=%d",
969 ref);
970 unlock_buffer(new_bh);
971 error = ext4_handle_dirty_xattr_block(handle,
972 inode,
973 new_bh);
974 if (error)
975 goto cleanup_dquot;
976 }
977 mb_cache_entry_touch(ext4_mb_cache, ce);
978 mb_cache_entry_put(ext4_mb_cache, ce);
979 ce = NULL;
980 } else if (bs->bh && s->base == bs->bh->b_data) {
981 /* We were modifying this block in-place. */
982 ea_bdebug(bs->bh, "keeping this block");
983 new_bh = bs->bh;
984 get_bh(new_bh);
985 } else {
986 /* We need to allocate a new block */
987 ext4_fsblk_t goal, block;
988
989 goal = ext4_group_first_block_no(sb,
990 EXT4_I(inode)->i_block_group);
991
992 /* non-extent files can't have physical blocks past 2^32 */
993 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
994 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
995
996 block = ext4_new_meta_blocks(handle, inode, goal, 0,
997 NULL, &error);
998 if (error)
999 goto cleanup;
1000
1001 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
1002 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
1003
1004 ea_idebug(inode, "creating block %llu",
1005 (unsigned long long)block);
1006
1007 new_bh = sb_getblk(sb, block);
1008 if (unlikely(!new_bh)) {
1009 error = -ENOMEM;
1010 getblk_failed:
1011 ext4_free_blocks(handle, inode, NULL, block, 1,
1012 EXT4_FREE_BLOCKS_METADATA);
1013 goto cleanup;
1014 }
1015 lock_buffer(new_bh);
1016 error = ext4_journal_get_create_access(handle, new_bh);
1017 if (error) {
1018 unlock_buffer(new_bh);
1019 error = -EIO;
1020 goto getblk_failed;
1021 }
1022 memcpy(new_bh->b_data, s->base, new_bh->b_size);
1023 set_buffer_uptodate(new_bh);
1024 unlock_buffer(new_bh);
1025 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1026 error = ext4_handle_dirty_xattr_block(handle,
1027 inode, new_bh);
1028 if (error)
1029 goto cleanup;
1030 }
1031 }
1032
1033 /* Update the inode. */
1034 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1035
1036 /* Drop the previous xattr block. */
1037 if (bs->bh && bs->bh != new_bh)
1038 ext4_xattr_release_block(handle, inode, bs->bh);
1039 error = 0;
1040
1041 cleanup:
1042 if (ce)
1043 mb_cache_entry_put(ext4_mb_cache, ce);
1044 brelse(new_bh);
1045 if (!(bs->bh && s->base == bs->bh->b_data))
1046 kfree(s->base);
1047
1048 return error;
1049
1050 cleanup_dquot:
1051 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1052 goto cleanup;
1053
1054 bad_block:
1055 EXT4_ERROR_INODE(inode, "bad block %llu",
1056 EXT4_I(inode)->i_file_acl);
1057 goto cleanup;
1058
1059 #undef header
1060 }
1061
1062 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
1063 struct ext4_xattr_ibody_find *is)
1064 {
1065 struct ext4_xattr_ibody_header *header;
1066 struct ext4_inode *raw_inode;
1067 int error;
1068
1069 if (EXT4_I(inode)->i_extra_isize == 0)
1070 return 0;
1071 raw_inode = ext4_raw_inode(&is->iloc);
1072 header = IHDR(inode, raw_inode);
1073 is->s.base = is->s.first = IFIRST(header);
1074 is->s.here = is->s.first;
1075 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1076 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1077 error = xattr_check_inode(inode, header, is->s.end);
1078 if (error)
1079 return error;
1080 /* Find the named attribute. */
1081 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1082 i->name, is->s.end -
1083 (void *)is->s.base, 0);
1084 if (error && error != -ENODATA)
1085 return error;
1086 is->s.not_found = error;
1087 }
1088 return 0;
1089 }
1090
1091 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1092 struct ext4_xattr_info *i,
1093 struct ext4_xattr_ibody_find *is)
1094 {
1095 struct ext4_xattr_ibody_header *header;
1096 struct ext4_xattr_search *s = &is->s;
1097 int error;
1098
1099 if (EXT4_I(inode)->i_extra_isize == 0)
1100 return -ENOSPC;
1101 error = ext4_xattr_set_entry(i, s);
1102 if (error) {
1103 if (error == -ENOSPC &&
1104 ext4_has_inline_data(inode)) {
1105 error = ext4_try_to_evict_inline_data(handle, inode,
1106 EXT4_XATTR_LEN(strlen(i->name) +
1107 EXT4_XATTR_SIZE(i->value_len)));
1108 if (error)
1109 return error;
1110 error = ext4_xattr_ibody_find(inode, i, is);
1111 if (error)
1112 return error;
1113 error = ext4_xattr_set_entry(i, s);
1114 }
1115 if (error)
1116 return error;
1117 }
1118 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1119 if (!IS_LAST_ENTRY(s->first)) {
1120 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1121 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1122 } else {
1123 header->h_magic = cpu_to_le32(0);
1124 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1125 }
1126 return 0;
1127 }
1128
1129 static int ext4_xattr_ibody_set(struct inode *inode,
1130 struct ext4_xattr_info *i,
1131 struct ext4_xattr_ibody_find *is)
1132 {
1133 struct ext4_xattr_ibody_header *header;
1134 struct ext4_xattr_search *s = &is->s;
1135 int error;
1136
1137 if (EXT4_I(inode)->i_extra_isize == 0)
1138 return -ENOSPC;
1139 error = ext4_xattr_set_entry(i, s);
1140 if (error)
1141 return error;
1142 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1143 if (!IS_LAST_ENTRY(s->first)) {
1144 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1145 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1146 } else {
1147 header->h_magic = cpu_to_le32(0);
1148 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1149 }
1150 return 0;
1151 }
1152
1153 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
1154 struct ext4_xattr_info *i)
1155 {
1156 void *value;
1157
1158 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
1159 return 0;
1160 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
1161 return !memcmp(value, i->value, i->value_len);
1162 }
1163
1164 /*
1165 * ext4_xattr_set_handle()
1166 *
1167 * Create, replace or remove an extended attribute for this inode. Value
1168 * is NULL to remove an existing extended attribute, and non-NULL to
1169 * either replace an existing extended attribute, or create a new extended
1170 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1171 * specify that an extended attribute must exist and must not exist
1172 * previous to the call, respectively.
1173 *
1174 * Returns 0, or a negative error number on failure.
1175 */
1176 int
1177 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1178 const char *name, const void *value, size_t value_len,
1179 int flags)
1180 {
1181 struct ext4_xattr_info i = {
1182 .name_index = name_index,
1183 .name = name,
1184 .value = value,
1185 .value_len = value_len,
1186
1187 };
1188 struct ext4_xattr_ibody_find is = {
1189 .s = { .not_found = -ENODATA, },
1190 };
1191 struct ext4_xattr_block_find bs = {
1192 .s = { .not_found = -ENODATA, },
1193 };
1194 int no_expand;
1195 int error;
1196
1197 if (!name)
1198 return -EINVAL;
1199 if (strlen(name) > 255)
1200 return -ERANGE;
1201 ext4_write_lock_xattr(inode, &no_expand);
1202
1203 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1204 if (error)
1205 goto cleanup;
1206
1207 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1208 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1209 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1210 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1211 }
1212
1213 error = ext4_xattr_ibody_find(inode, &i, &is);
1214 if (error)
1215 goto cleanup;
1216 if (is.s.not_found)
1217 error = ext4_xattr_block_find(inode, &i, &bs);
1218 if (error)
1219 goto cleanup;
1220 if (is.s.not_found && bs.s.not_found) {
1221 error = -ENODATA;
1222 if (flags & XATTR_REPLACE)
1223 goto cleanup;
1224 error = 0;
1225 if (!value)
1226 goto cleanup;
1227 } else {
1228 error = -EEXIST;
1229 if (flags & XATTR_CREATE)
1230 goto cleanup;
1231 }
1232 if (!value) {
1233 if (!is.s.not_found)
1234 error = ext4_xattr_ibody_set(inode, &i, &is);
1235 else if (!bs.s.not_found)
1236 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1237 } else {
1238 error = 0;
1239 /* Xattr value did not change? Save us some work and bail out */
1240 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
1241 goto cleanup;
1242 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
1243 goto cleanup;
1244
1245 error = ext4_xattr_ibody_set(inode, &i, &is);
1246 if (!error && !bs.s.not_found) {
1247 i.value = NULL;
1248 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1249 } else if (error == -ENOSPC) {
1250 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1251 error = ext4_xattr_block_find(inode, &i, &bs);
1252 if (error)
1253 goto cleanup;
1254 }
1255 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1256 if (error)
1257 goto cleanup;
1258 if (!is.s.not_found) {
1259 i.value = NULL;
1260 error = ext4_xattr_ibody_set(inode, &i, &is);
1261 }
1262 }
1263 }
1264 if (!error) {
1265 ext4_xattr_update_super_block(handle, inode->i_sb);
1266 inode->i_ctime = current_time(inode);
1267 if (!value)
1268 no_expand = 0;
1269 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1270 /*
1271 * The bh is consumed by ext4_mark_iloc_dirty, even with
1272 * error != 0.
1273 */
1274 is.iloc.bh = NULL;
1275 if (IS_SYNC(inode))
1276 ext4_handle_sync(handle);
1277 }
1278
1279 cleanup:
1280 brelse(is.iloc.bh);
1281 brelse(bs.bh);
1282 ext4_write_unlock_xattr(inode, &no_expand);
1283 return error;
1284 }
1285
1286 /*
1287 * ext4_xattr_set()
1288 *
1289 * Like ext4_xattr_set_handle, but start from an inode. This extended
1290 * attribute modification is a filesystem transaction by itself.
1291 *
1292 * Returns 0, or a negative error number on failure.
1293 */
1294 int
1295 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1296 const void *value, size_t value_len, int flags)
1297 {
1298 handle_t *handle;
1299 int error, retries = 0;
1300 int credits = ext4_jbd2_credits_xattr(inode);
1301
1302 retry:
1303 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1304 if (IS_ERR(handle)) {
1305 error = PTR_ERR(handle);
1306 } else {
1307 int error2;
1308
1309 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1310 value, value_len, flags);
1311 error2 = ext4_journal_stop(handle);
1312 if (error == -ENOSPC &&
1313 ext4_should_retry_alloc(inode->i_sb, &retries))
1314 goto retry;
1315 if (error == 0)
1316 error = error2;
1317 }
1318
1319 return error;
1320 }
1321
1322 /*
1323 * Shift the EA entries in the inode to create space for the increased
1324 * i_extra_isize.
1325 */
1326 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1327 int value_offs_shift, void *to,
1328 void *from, size_t n)
1329 {
1330 struct ext4_xattr_entry *last = entry;
1331 int new_offs;
1332
1333 /* We always shift xattr headers further thus offsets get lower */
1334 BUG_ON(value_offs_shift > 0);
1335
1336 /* Adjust the value offsets of the entries */
1337 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1338 if (last->e_value_size) {
1339 new_offs = le16_to_cpu(last->e_value_offs) +
1340 value_offs_shift;
1341 last->e_value_offs = cpu_to_le16(new_offs);
1342 }
1343 }
1344 /* Shift the entries by n bytes */
1345 memmove(to, from, n);
1346 }
1347
1348 /*
1349 * Move xattr pointed to by 'entry' from inode into external xattr block
1350 */
1351 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
1352 struct ext4_inode *raw_inode,
1353 struct ext4_xattr_entry *entry)
1354 {
1355 struct ext4_xattr_ibody_find *is = NULL;
1356 struct ext4_xattr_block_find *bs = NULL;
1357 char *buffer = NULL, *b_entry_name = NULL;
1358 size_t value_offs, value_size;
1359 struct ext4_xattr_info i = {
1360 .value = NULL,
1361 .value_len = 0,
1362 .name_index = entry->e_name_index,
1363 };
1364 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1365 int error;
1366
1367 value_offs = le16_to_cpu(entry->e_value_offs);
1368 value_size = le32_to_cpu(entry->e_value_size);
1369
1370 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1371 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1372 buffer = kmalloc(value_size, GFP_NOFS);
1373 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1374 if (!is || !bs || !buffer || !b_entry_name) {
1375 error = -ENOMEM;
1376 goto out;
1377 }
1378
1379 is->s.not_found = -ENODATA;
1380 bs->s.not_found = -ENODATA;
1381 is->iloc.bh = NULL;
1382 bs->bh = NULL;
1383
1384 /* Save the entry name and the entry value */
1385 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
1386 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1387 b_entry_name[entry->e_name_len] = '\0';
1388 i.name = b_entry_name;
1389
1390 error = ext4_get_inode_loc(inode, &is->iloc);
1391 if (error)
1392 goto out;
1393
1394 error = ext4_xattr_ibody_find(inode, &i, is);
1395 if (error)
1396 goto out;
1397
1398 /* Remove the chosen entry from the inode */
1399 error = ext4_xattr_ibody_set(inode, &i, is);
1400 if (error)
1401 goto out;
1402
1403 i.name = b_entry_name;
1404 i.value = buffer;
1405 i.value_len = value_size;
1406 error = ext4_xattr_block_find(inode, &i, bs);
1407 if (error)
1408 goto out;
1409
1410 /* Add entry which was removed from the inode into the block */
1411 error = ext4_xattr_block_set(handle, inode, &i, bs);
1412 if (error)
1413 goto out;
1414 error = 0;
1415 out:
1416 kfree(b_entry_name);
1417 kfree(buffer);
1418 if (is)
1419 brelse(is->iloc.bh);
1420 kfree(is);
1421 kfree(bs);
1422
1423 return error;
1424 }
1425
1426 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
1427 struct ext4_inode *raw_inode,
1428 int isize_diff, size_t ifree,
1429 size_t bfree, int *total_ino)
1430 {
1431 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1432 struct ext4_xattr_entry *small_entry;
1433 struct ext4_xattr_entry *entry;
1434 struct ext4_xattr_entry *last;
1435 unsigned int entry_size; /* EA entry size */
1436 unsigned int total_size; /* EA entry size + value size */
1437 unsigned int min_total_size;
1438 int error;
1439
1440 while (isize_diff > ifree) {
1441 entry = NULL;
1442 small_entry = NULL;
1443 min_total_size = ~0U;
1444 last = IFIRST(header);
1445 /* Find the entry best suited to be pushed into EA block */
1446 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1447 total_size =
1448 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1449 EXT4_XATTR_LEN(last->e_name_len);
1450 if (total_size <= bfree &&
1451 total_size < min_total_size) {
1452 if (total_size + ifree < isize_diff) {
1453 small_entry = last;
1454 } else {
1455 entry = last;
1456 min_total_size = total_size;
1457 }
1458 }
1459 }
1460
1461 if (entry == NULL) {
1462 if (small_entry == NULL)
1463 return -ENOSPC;
1464 entry = small_entry;
1465 }
1466
1467 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1468 total_size = entry_size +
1469 EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
1470 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
1471 entry);
1472 if (error)
1473 return error;
1474
1475 *total_ino -= entry_size;
1476 ifree += total_size;
1477 bfree -= total_size;
1478 }
1479
1480 return 0;
1481 }
1482
1483 /*
1484 * Expand an inode by new_extra_isize bytes when EAs are present.
1485 * Returns 0 on success or negative error number on failure.
1486 */
1487 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1488 struct ext4_inode *raw_inode, handle_t *handle)
1489 {
1490 struct ext4_xattr_ibody_header *header;
1491 struct buffer_head *bh = NULL;
1492 size_t min_offs;
1493 size_t ifree, bfree;
1494 int total_ino;
1495 void *base, *end;
1496 int error = 0, tried_min_extra_isize = 0;
1497 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1498 int isize_diff; /* How much do we need to grow i_extra_isize */
1499 int no_expand;
1500
1501 if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
1502 return 0;
1503
1504 retry:
1505 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
1506 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
1507 goto out;
1508
1509 header = IHDR(inode, raw_inode);
1510
1511 /*
1512 * Check if enough free space is available in the inode to shift the
1513 * entries ahead by new_extra_isize.
1514 */
1515
1516 base = IFIRST(header);
1517 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1518 min_offs = end - base;
1519 total_ino = sizeof(struct ext4_xattr_ibody_header);
1520
1521 error = xattr_check_inode(inode, header, end);
1522 if (error)
1523 goto cleanup;
1524
1525 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
1526 if (ifree >= isize_diff)
1527 goto shift;
1528
1529 /*
1530 * Enough free space isn't available in the inode, check if
1531 * EA block can hold new_extra_isize bytes.
1532 */
1533 if (EXT4_I(inode)->i_file_acl) {
1534 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1535 error = -EIO;
1536 if (!bh)
1537 goto cleanup;
1538 if (ext4_xattr_check_block(inode, bh)) {
1539 EXT4_ERROR_INODE(inode, "bad block %llu",
1540 EXT4_I(inode)->i_file_acl);
1541 error = -EFSCORRUPTED;
1542 goto cleanup;
1543 }
1544 base = BHDR(bh);
1545 end = bh->b_data + bh->b_size;
1546 min_offs = end - base;
1547 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
1548 NULL);
1549 if (bfree + ifree < isize_diff) {
1550 if (!tried_min_extra_isize && s_min_extra_isize) {
1551 tried_min_extra_isize++;
1552 new_extra_isize = s_min_extra_isize;
1553 brelse(bh);
1554 goto retry;
1555 }
1556 error = -ENOSPC;
1557 goto cleanup;
1558 }
1559 } else {
1560 bfree = inode->i_sb->s_blocksize;
1561 }
1562
1563 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
1564 isize_diff, ifree, bfree,
1565 &total_ino);
1566 if (error) {
1567 if (error == -ENOSPC && !tried_min_extra_isize &&
1568 s_min_extra_isize) {
1569 tried_min_extra_isize++;
1570 new_extra_isize = s_min_extra_isize;
1571 brelse(bh);
1572 goto retry;
1573 }
1574 goto cleanup;
1575 }
1576 shift:
1577 /* Adjust the offsets and shift the remaining entries ahead */
1578 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
1579 - new_extra_isize, (void *)raw_inode +
1580 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1581 (void *)header, total_ino);
1582 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1583 brelse(bh);
1584 out:
1585 ext4_write_unlock_xattr(inode, &no_expand);
1586 return 0;
1587
1588 cleanup:
1589 brelse(bh);
1590 /*
1591 * Inode size expansion failed; don't try again
1592 */
1593 no_expand = 1;
1594 ext4_write_unlock_xattr(inode, &no_expand);
1595 return error;
1596 }
1597
1598
1599
1600 /*
1601 * ext4_xattr_delete_inode()
1602 *
1603 * Free extended attribute resources associated with this inode. This
1604 * is called immediately before an inode is freed. We have exclusive
1605 * access to the inode.
1606 */
1607 void
1608 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1609 {
1610 struct buffer_head *bh = NULL;
1611
1612 if (!EXT4_I(inode)->i_file_acl)
1613 goto cleanup;
1614 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1615 if (!bh) {
1616 EXT4_ERROR_INODE(inode, "block %llu read error",
1617 EXT4_I(inode)->i_file_acl);
1618 goto cleanup;
1619 }
1620 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1621 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1622 EXT4_ERROR_INODE(inode, "bad block %llu",
1623 EXT4_I(inode)->i_file_acl);
1624 goto cleanup;
1625 }
1626 ext4_xattr_release_block(handle, inode, bh);
1627 EXT4_I(inode)->i_file_acl = 0;
1628
1629 cleanup:
1630 brelse(bh);
1631 }
1632
1633 /*
1634 * ext4_xattr_cache_insert()
1635 *
1636 * Create a new entry in the extended attribute cache, and insert
1637 * it unless such an entry is already in the cache.
1638 *
1639 * Returns 0, or a negative error number on failure.
1640 */
1641 static void
1642 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1643 {
1644 struct ext4_xattr_header *header = BHDR(bh);
1645 __u32 hash = le32_to_cpu(header->h_hash);
1646 int reusable = le32_to_cpu(header->h_refcount) <
1647 EXT4_XATTR_REFCOUNT_MAX;
1648 int error;
1649
1650 error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1651 bh->b_blocknr, reusable);
1652 if (error) {
1653 if (error == -EBUSY)
1654 ea_bdebug(bh, "already in cache");
1655 } else
1656 ea_bdebug(bh, "inserting [%x]", (int)hash);
1657 }
1658
1659 /*
1660 * ext4_xattr_cmp()
1661 *
1662 * Compare two extended attribute blocks for equality.
1663 *
1664 * Returns 0 if the blocks are equal, 1 if they differ, and
1665 * a negative error number on errors.
1666 */
1667 static int
1668 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1669 struct ext4_xattr_header *header2)
1670 {
1671 struct ext4_xattr_entry *entry1, *entry2;
1672
1673 entry1 = ENTRY(header1+1);
1674 entry2 = ENTRY(header2+1);
1675 while (!IS_LAST_ENTRY(entry1)) {
1676 if (IS_LAST_ENTRY(entry2))
1677 return 1;
1678 if (entry1->e_hash != entry2->e_hash ||
1679 entry1->e_name_index != entry2->e_name_index ||
1680 entry1->e_name_len != entry2->e_name_len ||
1681 entry1->e_value_size != entry2->e_value_size ||
1682 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1683 return 1;
1684 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1685 return -EFSCORRUPTED;
1686 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1687 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1688 le32_to_cpu(entry1->e_value_size)))
1689 return 1;
1690
1691 entry1 = EXT4_XATTR_NEXT(entry1);
1692 entry2 = EXT4_XATTR_NEXT(entry2);
1693 }
1694 if (!IS_LAST_ENTRY(entry2))
1695 return 1;
1696 return 0;
1697 }
1698
1699 /*
1700 * ext4_xattr_cache_find()
1701 *
1702 * Find an identical extended attribute block.
1703 *
1704 * Returns a pointer to the block found, or NULL if such a block was
1705 * not found or an error occurred.
1706 */
1707 static struct buffer_head *
1708 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1709 struct mb_cache_entry **pce)
1710 {
1711 __u32 hash = le32_to_cpu(header->h_hash);
1712 struct mb_cache_entry *ce;
1713 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1714
1715 if (!header->h_hash)
1716 return NULL; /* never share */
1717 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1718 ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1719 while (ce) {
1720 struct buffer_head *bh;
1721
1722 bh = sb_bread(inode->i_sb, ce->e_block);
1723 if (!bh) {
1724 EXT4_ERROR_INODE(inode, "block %lu read error",
1725 (unsigned long) ce->e_block);
1726 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1727 *pce = ce;
1728 return bh;
1729 }
1730 brelse(bh);
1731 ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1732 }
1733 return NULL;
1734 }
1735
1736 #define NAME_HASH_SHIFT 5
1737 #define VALUE_HASH_SHIFT 16
1738
1739 /*
1740 * ext4_xattr_hash_entry()
1741 *
1742 * Compute the hash of an extended attribute.
1743 */
1744 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1745 struct ext4_xattr_entry *entry)
1746 {
1747 __u32 hash = 0;
1748 char *name = entry->e_name;
1749 int n;
1750
1751 for (n = 0; n < entry->e_name_len; n++) {
1752 hash = (hash << NAME_HASH_SHIFT) ^
1753 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1754 *name++;
1755 }
1756
1757 if (entry->e_value_size != 0) {
1758 __le32 *value = (__le32 *)((char *)header +
1759 le16_to_cpu(entry->e_value_offs));
1760 for (n = (le32_to_cpu(entry->e_value_size) +
1761 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1762 hash = (hash << VALUE_HASH_SHIFT) ^
1763 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1764 le32_to_cpu(*value++);
1765 }
1766 }
1767 entry->e_hash = cpu_to_le32(hash);
1768 }
1769
1770 #undef NAME_HASH_SHIFT
1771 #undef VALUE_HASH_SHIFT
1772
1773 #define BLOCK_HASH_SHIFT 16
1774
1775 /*
1776 * ext4_xattr_rehash()
1777 *
1778 * Re-compute the extended attribute hash value after an entry has changed.
1779 */
1780 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1781 struct ext4_xattr_entry *entry)
1782 {
1783 struct ext4_xattr_entry *here;
1784 __u32 hash = 0;
1785
1786 ext4_xattr_hash_entry(header, entry);
1787 here = ENTRY(header+1);
1788 while (!IS_LAST_ENTRY(here)) {
1789 if (!here->e_hash) {
1790 /* Block is not shared if an entry's hash value == 0 */
1791 hash = 0;
1792 break;
1793 }
1794 hash = (hash << BLOCK_HASH_SHIFT) ^
1795 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1796 le32_to_cpu(here->e_hash);
1797 here = EXT4_XATTR_NEXT(here);
1798 }
1799 header->h_hash = cpu_to_le32(hash);
1800 }
1801
1802 #undef BLOCK_HASH_SHIFT
1803
1804 #define HASH_BUCKET_BITS 10
1805
1806 struct mb_cache *
1807 ext4_xattr_create_cache(void)
1808 {
1809 return mb_cache_create(HASH_BUCKET_BITS);
1810 }
1811
1812 void ext4_xattr_destroy_cache(struct mb_cache *cache)
1813 {
1814 if (cache)
1815 mb_cache_destroy(cache);
1816 }
1817
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