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Merge branch 'master' of ssh://master.kernel.org/pub/scm/linux/kernel/git/linville...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ext4 / xattr.c
blobf3a2f7ed45aabc13e3ea4a28fc9baa098131cbb4
1 /*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16 /*
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53 #include <linux/init.h>
54 #include <linux/fs.h>
55 #include <linux/slab.h>
56 #include <linux/mbcache.h>
57 #include <linux/quotaops.h>
58 #include <linux/rwsem.h>
59 #include "ext4_jbd2.h"
60 #include "ext4.h"
61 #include "xattr.h"
62 #include "acl.h"
63
64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
68
69 #ifdef EXT4_XATTR_DEBUG
70 # define ea_idebug(inode, f...) do { \
71 printk(KERN_DEBUG "inode %s:%lu: ", \
72 inode->i_sb->s_id, inode->i_ino); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76 # define ea_bdebug(bh, f...) do { \
77 char b[BDEVNAME_SIZE]; \
78 printk(KERN_DEBUG "block %s:%lu: ", \
79 bdevname(bh->b_bdev, b), \
80 (unsigned long) bh->b_blocknr); \
81 printk(f); \
82 printk("\n"); \
83 } while (0)
84 #else
85 # define ea_idebug(f...)
86 # define ea_bdebug(f...)
87 #endif
88
89 static void ext4_xattr_cache_insert(struct buffer_head *);
90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
91 struct ext4_xattr_header *,
92 struct mb_cache_entry **);
93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
94 struct ext4_xattr_entry *);
95 static int ext4_xattr_list(struct dentry *dentry, char *buffer,
96 size_t buffer_size);
97
98 static struct mb_cache *ext4_xattr_cache;
99
100 static struct xattr_handler *ext4_xattr_handler_map[] = {
101 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
103 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
104 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
105 #endif
106 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
107 #ifdef CONFIG_EXT4_FS_SECURITY
108 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
109 #endif
110 };
111
112 struct xattr_handler *ext4_xattr_handlers[] = {
113 &ext4_xattr_user_handler,
114 &ext4_xattr_trusted_handler,
115 #ifdef CONFIG_EXT4_FS_POSIX_ACL
116 &ext4_xattr_acl_access_handler,
117 &ext4_xattr_acl_default_handler,
118 #endif
119 #ifdef CONFIG_EXT4_FS_SECURITY
120 &ext4_xattr_security_handler,
121 #endif
122 NULL
123 };
124
125 static inline struct xattr_handler *
126 ext4_xattr_handler(int name_index)
127 {
128 struct xattr_handler *handler = NULL;
129
130 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
131 handler = ext4_xattr_handler_map[name_index];
132 return handler;
133 }
134
135 /*
136 * Inode operation listxattr()
137 *
138 * dentry->d_inode->i_mutex: don't care
139 */
140 ssize_t
141 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
142 {
143 return ext4_xattr_list(dentry, buffer, size);
144 }
145
146 static int
147 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
148 {
149 while (!IS_LAST_ENTRY(entry)) {
150 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
151 if ((void *)next >= end)
152 return -EIO;
153 entry = next;
154 }
155 return 0;
156 }
157
158 static inline int
159 ext4_xattr_check_block(struct buffer_head *bh)
160 {
161 int error;
162
163 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
164 BHDR(bh)->h_blocks != cpu_to_le32(1))
165 return -EIO;
166 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
167 return error;
168 }
169
170 static inline int
171 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
172 {
173 size_t value_size = le32_to_cpu(entry->e_value_size);
174
175 if (entry->e_value_block != 0 || value_size > size ||
176 le16_to_cpu(entry->e_value_offs) + value_size > size)
177 return -EIO;
178 return 0;
179 }
180
181 static int
182 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
183 const char *name, size_t size, int sorted)
184 {
185 struct ext4_xattr_entry *entry;
186 size_t name_len;
187 int cmp = 1;
188
189 if (name == NULL)
190 return -EINVAL;
191 name_len = strlen(name);
192 entry = *pentry;
193 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
194 cmp = name_index - entry->e_name_index;
195 if (!cmp)
196 cmp = name_len - entry->e_name_len;
197 if (!cmp)
198 cmp = memcmp(name, entry->e_name, name_len);
199 if (cmp <= 0 && (sorted || cmp == 0))
200 break;
201 }
202 *pentry = entry;
203 if (!cmp && ext4_xattr_check_entry(entry, size))
204 return -EIO;
205 return cmp ? -ENODATA : 0;
206 }
207
208 static int
209 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
210 void *buffer, size_t buffer_size)
211 {
212 struct buffer_head *bh = NULL;
213 struct ext4_xattr_entry *entry;
214 size_t size;
215 int error;
216
217 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
218 name_index, name, buffer, (long)buffer_size);
219
220 error = -ENODATA;
221 if (!EXT4_I(inode)->i_file_acl)
222 goto cleanup;
223 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
224 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
225 if (!bh)
226 goto cleanup;
227 ea_bdebug(bh, "b_count=%d, refcount=%d",
228 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
229 if (ext4_xattr_check_block(bh)) {
230 bad_block: ext4_error(inode->i_sb, __func__,
231 "inode %lu: bad block %llu", inode->i_ino,
232 EXT4_I(inode)->i_file_acl);
233 error = -EIO;
234 goto cleanup;
235 }
236 ext4_xattr_cache_insert(bh);
237 entry = BFIRST(bh);
238 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
239 if (error == -EIO)
240 goto bad_block;
241 if (error)
242 goto cleanup;
243 size = le32_to_cpu(entry->e_value_size);
244 if (buffer) {
245 error = -ERANGE;
246 if (size > buffer_size)
247 goto cleanup;
248 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
249 size);
250 }
251 error = size;
252
253 cleanup:
254 brelse(bh);
255 return error;
256 }
257
258 static int
259 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
260 void *buffer, size_t buffer_size)
261 {
262 struct ext4_xattr_ibody_header *header;
263 struct ext4_xattr_entry *entry;
264 struct ext4_inode *raw_inode;
265 struct ext4_iloc iloc;
266 size_t size;
267 void *end;
268 int error;
269
270 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
271 return -ENODATA;
272 error = ext4_get_inode_loc(inode, &iloc);
273 if (error)
274 return error;
275 raw_inode = ext4_raw_inode(&iloc);
276 header = IHDR(inode, raw_inode);
277 entry = IFIRST(header);
278 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
279 error = ext4_xattr_check_names(entry, end);
280 if (error)
281 goto cleanup;
282 error = ext4_xattr_find_entry(&entry, name_index, name,
283 end - (void *)entry, 0);
284 if (error)
285 goto cleanup;
286 size = le32_to_cpu(entry->e_value_size);
287 if (buffer) {
288 error = -ERANGE;
289 if (size > buffer_size)
290 goto cleanup;
291 memcpy(buffer, (void *)IFIRST(header) +
292 le16_to_cpu(entry->e_value_offs), size);
293 }
294 error = size;
295
296 cleanup:
297 brelse(iloc.bh);
298 return error;
299 }
300
301 /*
302 * ext4_xattr_get()
303 *
304 * Copy an extended attribute into the buffer
305 * provided, or compute the buffer size required.
306 * Buffer is NULL to compute the size of the buffer required.
307 *
308 * Returns a negative error number on failure, or the number of bytes
309 * used / required on success.
310 */
311 int
312 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
313 void *buffer, size_t buffer_size)
314 {
315 int error;
316
317 down_read(&EXT4_I(inode)->xattr_sem);
318 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
319 buffer_size);
320 if (error == -ENODATA)
321 error = ext4_xattr_block_get(inode, name_index, name, buffer,
322 buffer_size);
323 up_read(&EXT4_I(inode)->xattr_sem);
324 return error;
325 }
326
327 static int
328 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
329 char *buffer, size_t buffer_size)
330 {
331 size_t rest = buffer_size;
332
333 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
334 struct xattr_handler *handler =
335 ext4_xattr_handler(entry->e_name_index);
336
337 if (handler) {
338 size_t size = handler->list(dentry, buffer, rest,
339 entry->e_name,
340 entry->e_name_len,
341 handler->flags);
342 if (buffer) {
343 if (size > rest)
344 return -ERANGE;
345 buffer += size;
346 }
347 rest -= size;
348 }
349 }
350 return buffer_size - rest;
351 }
352
353 static int
354 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
355 {
356 struct inode *inode = dentry->d_inode;
357 struct buffer_head *bh = NULL;
358 int error;
359
360 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
361 buffer, (long)buffer_size);
362
363 error = 0;
364 if (!EXT4_I(inode)->i_file_acl)
365 goto cleanup;
366 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
367 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
368 error = -EIO;
369 if (!bh)
370 goto cleanup;
371 ea_bdebug(bh, "b_count=%d, refcount=%d",
372 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
373 if (ext4_xattr_check_block(bh)) {
374 ext4_error(inode->i_sb, __func__,
375 "inode %lu: bad block %llu", inode->i_ino,
376 EXT4_I(inode)->i_file_acl);
377 error = -EIO;
378 goto cleanup;
379 }
380 ext4_xattr_cache_insert(bh);
381 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
382
383 cleanup:
384 brelse(bh);
385
386 return error;
387 }
388
389 static int
390 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
391 {
392 struct inode *inode = dentry->d_inode;
393 struct ext4_xattr_ibody_header *header;
394 struct ext4_inode *raw_inode;
395 struct ext4_iloc iloc;
396 void *end;
397 int error;
398
399 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
400 return 0;
401 error = ext4_get_inode_loc(inode, &iloc);
402 if (error)
403 return error;
404 raw_inode = ext4_raw_inode(&iloc);
405 header = IHDR(inode, raw_inode);
406 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
407 error = ext4_xattr_check_names(IFIRST(header), end);
408 if (error)
409 goto cleanup;
410 error = ext4_xattr_list_entries(dentry, IFIRST(header),
411 buffer, buffer_size);
412
413 cleanup:
414 brelse(iloc.bh);
415 return error;
416 }
417
418 /*
419 * ext4_xattr_list()
420 *
421 * Copy a list of attribute names into the buffer
422 * provided, or compute the buffer size required.
423 * Buffer is NULL to compute the size of the buffer required.
424 *
425 * Returns a negative error number on failure, or the number of bytes
426 * used / required on success.
427 */
428 static int
429 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
430 {
431 int i_error, b_error;
432
433 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
434 i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
435 if (i_error < 0) {
436 b_error = 0;
437 } else {
438 if (buffer) {
439 buffer += i_error;
440 buffer_size -= i_error;
441 }
442 b_error = ext4_xattr_block_list(dentry, buffer, buffer_size);
443 if (b_error < 0)
444 i_error = 0;
445 }
446 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
447 return i_error + b_error;
448 }
449
450 /*
451 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
452 * not set, set it.
453 */
454 static void ext4_xattr_update_super_block(handle_t *handle,
455 struct super_block *sb)
456 {
457 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
458 return;
459
460 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
461 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
462 sb->s_dirt = 1;
463 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
464 }
465 }
466
467 /*
468 * Release the xattr block BH: If the reference count is > 1, decrement
469 * it; otherwise free the block.
470 */
471 static void
472 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
473 struct buffer_head *bh)
474 {
475 struct mb_cache_entry *ce = NULL;
476 int error = 0;
477
478 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
479 error = ext4_journal_get_write_access(handle, bh);
480 if (error)
481 goto out;
482
483 lock_buffer(bh);
484 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
485 ea_bdebug(bh, "refcount now=0; freeing");
486 if (ce)
487 mb_cache_entry_free(ce);
488 get_bh(bh);
489 ext4_free_blocks(handle, inode, bh, 0, 1,
490 EXT4_FREE_BLOCKS_METADATA |
491 EXT4_FREE_BLOCKS_FORGET);
492 } else {
493 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
494 error = ext4_handle_dirty_metadata(handle, inode, bh);
495 if (IS_SYNC(inode))
496 ext4_handle_sync(handle);
497 vfs_dq_free_block(inode, 1);
498 ea_bdebug(bh, "refcount now=%d; releasing",
499 le32_to_cpu(BHDR(bh)->h_refcount));
500 if (ce)
501 mb_cache_entry_release(ce);
502 }
503 unlock_buffer(bh);
504 out:
505 ext4_std_error(inode->i_sb, error);
506 return;
507 }
508
509 /*
510 * Find the available free space for EAs. This also returns the total number of
511 * bytes used by EA entries.
512 */
513 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
514 size_t *min_offs, void *base, int *total)
515 {
516 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
517 *total += EXT4_XATTR_LEN(last->e_name_len);
518 if (!last->e_value_block && last->e_value_size) {
519 size_t offs = le16_to_cpu(last->e_value_offs);
520 if (offs < *min_offs)
521 *min_offs = offs;
522 }
523 }
524 return (*min_offs - ((void *)last - base) - sizeof(__u32));
525 }
526
527 struct ext4_xattr_info {
528 int name_index;
529 const char *name;
530 const void *value;
531 size_t value_len;
532 };
533
534 struct ext4_xattr_search {
535 struct ext4_xattr_entry *first;
536 void *base;
537 void *end;
538 struct ext4_xattr_entry *here;
539 int not_found;
540 };
541
542 static int
543 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
544 {
545 struct ext4_xattr_entry *last;
546 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
547
548 /* Compute min_offs and last. */
549 last = s->first;
550 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
551 if (!last->e_value_block && last->e_value_size) {
552 size_t offs = le16_to_cpu(last->e_value_offs);
553 if (offs < min_offs)
554 min_offs = offs;
555 }
556 }
557 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
558 if (!s->not_found) {
559 if (!s->here->e_value_block && s->here->e_value_size) {
560 size_t size = le32_to_cpu(s->here->e_value_size);
561 free += EXT4_XATTR_SIZE(size);
562 }
563 free += EXT4_XATTR_LEN(name_len);
564 }
565 if (i->value) {
566 if (free < EXT4_XATTR_SIZE(i->value_len) ||
567 free < EXT4_XATTR_LEN(name_len) +
568 EXT4_XATTR_SIZE(i->value_len))
569 return -ENOSPC;
570 }
571
572 if (i->value && s->not_found) {
573 /* Insert the new name. */
574 size_t size = EXT4_XATTR_LEN(name_len);
575 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
576 memmove((void *)s->here + size, s->here, rest);
577 memset(s->here, 0, size);
578 s->here->e_name_index = i->name_index;
579 s->here->e_name_len = name_len;
580 memcpy(s->here->e_name, i->name, name_len);
581 } else {
582 if (!s->here->e_value_block && s->here->e_value_size) {
583 void *first_val = s->base + min_offs;
584 size_t offs = le16_to_cpu(s->here->e_value_offs);
585 void *val = s->base + offs;
586 size_t size = EXT4_XATTR_SIZE(
587 le32_to_cpu(s->here->e_value_size));
588
589 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
590 /* The old and the new value have the same
591 size. Just replace. */
592 s->here->e_value_size =
593 cpu_to_le32(i->value_len);
594 memset(val + size - EXT4_XATTR_PAD, 0,
595 EXT4_XATTR_PAD); /* Clear pad bytes. */
596 memcpy(val, i->value, i->value_len);
597 return 0;
598 }
599
600 /* Remove the old value. */
601 memmove(first_val + size, first_val, val - first_val);
602 memset(first_val, 0, size);
603 s->here->e_value_size = 0;
604 s->here->e_value_offs = 0;
605 min_offs += size;
606
607 /* Adjust all value offsets. */
608 last = s->first;
609 while (!IS_LAST_ENTRY(last)) {
610 size_t o = le16_to_cpu(last->e_value_offs);
611 if (!last->e_value_block &&
612 last->e_value_size && o < offs)
613 last->e_value_offs =
614 cpu_to_le16(o + size);
615 last = EXT4_XATTR_NEXT(last);
616 }
617 }
618 if (!i->value) {
619 /* Remove the old name. */
620 size_t size = EXT4_XATTR_LEN(name_len);
621 last = ENTRY((void *)last - size);
622 memmove(s->here, (void *)s->here + size,
623 (void *)last - (void *)s->here + sizeof(__u32));
624 memset(last, 0, size);
625 }
626 }
627
628 if (i->value) {
629 /* Insert the new value. */
630 s->here->e_value_size = cpu_to_le32(i->value_len);
631 if (i->value_len) {
632 size_t size = EXT4_XATTR_SIZE(i->value_len);
633 void *val = s->base + min_offs - size;
634 s->here->e_value_offs = cpu_to_le16(min_offs - size);
635 memset(val + size - EXT4_XATTR_PAD, 0,
636 EXT4_XATTR_PAD); /* Clear the pad bytes. */
637 memcpy(val, i->value, i->value_len);
638 }
639 }
640 return 0;
641 }
642
643 struct ext4_xattr_block_find {
644 struct ext4_xattr_search s;
645 struct buffer_head *bh;
646 };
647
648 static int
649 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
650 struct ext4_xattr_block_find *bs)
651 {
652 struct super_block *sb = inode->i_sb;
653 int error;
654
655 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
656 i->name_index, i->name, i->value, (long)i->value_len);
657
658 if (EXT4_I(inode)->i_file_acl) {
659 /* The inode already has an extended attribute block. */
660 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
661 error = -EIO;
662 if (!bs->bh)
663 goto cleanup;
664 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
665 atomic_read(&(bs->bh->b_count)),
666 le32_to_cpu(BHDR(bs->bh)->h_refcount));
667 if (ext4_xattr_check_block(bs->bh)) {
668 ext4_error(sb, __func__,
669 "inode %lu: bad block %llu", inode->i_ino,
670 EXT4_I(inode)->i_file_acl);
671 error = -EIO;
672 goto cleanup;
673 }
674 /* Find the named attribute. */
675 bs->s.base = BHDR(bs->bh);
676 bs->s.first = BFIRST(bs->bh);
677 bs->s.end = bs->bh->b_data + bs->bh->b_size;
678 bs->s.here = bs->s.first;
679 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
680 i->name, bs->bh->b_size, 1);
681 if (error && error != -ENODATA)
682 goto cleanup;
683 bs->s.not_found = error;
684 }
685 error = 0;
686
687 cleanup:
688 return error;
689 }
690
691 static int
692 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
693 struct ext4_xattr_info *i,
694 struct ext4_xattr_block_find *bs)
695 {
696 struct super_block *sb = inode->i_sb;
697 struct buffer_head *new_bh = NULL;
698 struct ext4_xattr_search *s = &bs->s;
699 struct mb_cache_entry *ce = NULL;
700 int error = 0;
701
702 #define header(x) ((struct ext4_xattr_header *)(x))
703
704 if (i->value && i->value_len > sb->s_blocksize)
705 return -ENOSPC;
706 if (s->base) {
707 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
708 bs->bh->b_blocknr);
709 error = ext4_journal_get_write_access(handle, bs->bh);
710 if (error)
711 goto cleanup;
712 lock_buffer(bs->bh);
713
714 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
715 if (ce) {
716 mb_cache_entry_free(ce);
717 ce = NULL;
718 }
719 ea_bdebug(bs->bh, "modifying in-place");
720 error = ext4_xattr_set_entry(i, s);
721 if (!error) {
722 if (!IS_LAST_ENTRY(s->first))
723 ext4_xattr_rehash(header(s->base),
724 s->here);
725 ext4_xattr_cache_insert(bs->bh);
726 }
727 unlock_buffer(bs->bh);
728 if (error == -EIO)
729 goto bad_block;
730 if (!error)
731 error = ext4_handle_dirty_metadata(handle,
732 inode,
733 bs->bh);
734 if (error)
735 goto cleanup;
736 goto inserted;
737 } else {
738 int offset = (char *)s->here - bs->bh->b_data;
739
740 unlock_buffer(bs->bh);
741 jbd2_journal_release_buffer(handle, bs->bh);
742 if (ce) {
743 mb_cache_entry_release(ce);
744 ce = NULL;
745 }
746 ea_bdebug(bs->bh, "cloning");
747 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
748 error = -ENOMEM;
749 if (s->base == NULL)
750 goto cleanup;
751 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
752 s->first = ENTRY(header(s->base)+1);
753 header(s->base)->h_refcount = cpu_to_le32(1);
754 s->here = ENTRY(s->base + offset);
755 s->end = s->base + bs->bh->b_size;
756 }
757 } else {
758 /* Allocate a buffer where we construct the new block. */
759 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
760 /* assert(header == s->base) */
761 error = -ENOMEM;
762 if (s->base == NULL)
763 goto cleanup;
764 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
765 header(s->base)->h_blocks = cpu_to_le32(1);
766 header(s->base)->h_refcount = cpu_to_le32(1);
767 s->first = ENTRY(header(s->base)+1);
768 s->here = ENTRY(header(s->base)+1);
769 s->end = s->base + sb->s_blocksize;
770 }
771
772 error = ext4_xattr_set_entry(i, s);
773 if (error == -EIO)
774 goto bad_block;
775 if (error)
776 goto cleanup;
777 if (!IS_LAST_ENTRY(s->first))
778 ext4_xattr_rehash(header(s->base), s->here);
779
780 inserted:
781 if (!IS_LAST_ENTRY(s->first)) {
782 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
783 if (new_bh) {
784 /* We found an identical block in the cache. */
785 if (new_bh == bs->bh)
786 ea_bdebug(new_bh, "keeping");
787 else {
788 /* The old block is released after updating
789 the inode. */
790 error = -EDQUOT;
791 if (vfs_dq_alloc_block(inode, 1))
792 goto cleanup;
793 error = ext4_journal_get_write_access(handle,
794 new_bh);
795 if (error)
796 goto cleanup_dquot;
797 lock_buffer(new_bh);
798 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
799 ea_bdebug(new_bh, "reusing; refcount now=%d",
800 le32_to_cpu(BHDR(new_bh)->h_refcount));
801 unlock_buffer(new_bh);
802 error = ext4_handle_dirty_metadata(handle,
803 inode,
804 new_bh);
805 if (error)
806 goto cleanup_dquot;
807 }
808 mb_cache_entry_release(ce);
809 ce = NULL;
810 } else if (bs->bh && s->base == bs->bh->b_data) {
811 /* We were modifying this block in-place. */
812 ea_bdebug(bs->bh, "keeping this block");
813 new_bh = bs->bh;
814 get_bh(new_bh);
815 } else {
816 /* We need to allocate a new block */
817 ext4_fsblk_t goal, block;
818
819 goal = ext4_group_first_block_no(sb,
820 EXT4_I(inode)->i_block_group);
821
822 /* non-extent files can't have physical blocks past 2^32 */
823 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
824 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
825
826 block = ext4_new_meta_blocks(handle, inode,
827 goal, NULL, &error);
828 if (error)
829 goto cleanup;
830
831 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
832 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
833
834 ea_idebug(inode, "creating block %d", block);
835
836 new_bh = sb_getblk(sb, block);
837 if (!new_bh) {
838 getblk_failed:
839 ext4_free_blocks(handle, inode, 0, block, 1,
840 EXT4_FREE_BLOCKS_METADATA);
841 error = -EIO;
842 goto cleanup;
843 }
844 lock_buffer(new_bh);
845 error = ext4_journal_get_create_access(handle, new_bh);
846 if (error) {
847 unlock_buffer(new_bh);
848 goto getblk_failed;
849 }
850 memcpy(new_bh->b_data, s->base, new_bh->b_size);
851 set_buffer_uptodate(new_bh);
852 unlock_buffer(new_bh);
853 ext4_xattr_cache_insert(new_bh);
854 error = ext4_handle_dirty_metadata(handle,
855 inode, new_bh);
856 if (error)
857 goto cleanup;
858 }
859 }
860
861 /* Update the inode. */
862 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
863
864 /* Drop the previous xattr block. */
865 if (bs->bh && bs->bh != new_bh)
866 ext4_xattr_release_block(handle, inode, bs->bh);
867 error = 0;
868
869 cleanup:
870 if (ce)
871 mb_cache_entry_release(ce);
872 brelse(new_bh);
873 if (!(bs->bh && s->base == bs->bh->b_data))
874 kfree(s->base);
875
876 return error;
877
878 cleanup_dquot:
879 vfs_dq_free_block(inode, 1);
880 goto cleanup;
881
882 bad_block:
883 ext4_error(inode->i_sb, __func__,
884 "inode %lu: bad block %llu", inode->i_ino,
885 EXT4_I(inode)->i_file_acl);
886 goto cleanup;
887
888 #undef header
889 }
890
891 struct ext4_xattr_ibody_find {
892 struct ext4_xattr_search s;
893 struct ext4_iloc iloc;
894 };
895
896 static int
897 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
898 struct ext4_xattr_ibody_find *is)
899 {
900 struct ext4_xattr_ibody_header *header;
901 struct ext4_inode *raw_inode;
902 int error;
903
904 if (EXT4_I(inode)->i_extra_isize == 0)
905 return 0;
906 raw_inode = ext4_raw_inode(&is->iloc);
907 header = IHDR(inode, raw_inode);
908 is->s.base = is->s.first = IFIRST(header);
909 is->s.here = is->s.first;
910 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
911 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
912 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
913 if (error)
914 return error;
915 /* Find the named attribute. */
916 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
917 i->name, is->s.end -
918 (void *)is->s.base, 0);
919 if (error && error != -ENODATA)
920 return error;
921 is->s.not_found = error;
922 }
923 return 0;
924 }
925
926 static int
927 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
928 struct ext4_xattr_info *i,
929 struct ext4_xattr_ibody_find *is)
930 {
931 struct ext4_xattr_ibody_header *header;
932 struct ext4_xattr_search *s = &is->s;
933 int error;
934
935 if (EXT4_I(inode)->i_extra_isize == 0)
936 return -ENOSPC;
937 error = ext4_xattr_set_entry(i, s);
938 if (error)
939 return error;
940 header = IHDR(inode, ext4_raw_inode(&is->iloc));
941 if (!IS_LAST_ENTRY(s->first)) {
942 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
943 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
944 } else {
945 header->h_magic = cpu_to_le32(0);
946 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
947 }
948 return 0;
949 }
950
951 /*
952 * ext4_xattr_set_handle()
953 *
954 * Create, replace or remove an extended attribute for this inode. Buffer
955 * is NULL to remove an existing extended attribute, and non-NULL to
956 * either replace an existing extended attribute, or create a new extended
957 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
958 * specify that an extended attribute must exist and must not exist
959 * previous to the call, respectively.
960 *
961 * Returns 0, or a negative error number on failure.
962 */
963 int
964 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
965 const char *name, const void *value, size_t value_len,
966 int flags)
967 {
968 struct ext4_xattr_info i = {
969 .name_index = name_index,
970 .name = name,
971 .value = value,
972 .value_len = value_len,
973
974 };
975 struct ext4_xattr_ibody_find is = {
976 .s = { .not_found = -ENODATA, },
977 };
978 struct ext4_xattr_block_find bs = {
979 .s = { .not_found = -ENODATA, },
980 };
981 unsigned long no_expand;
982 int error;
983
984 if (!name)
985 return -EINVAL;
986 if (strlen(name) > 255)
987 return -ERANGE;
988 down_write(&EXT4_I(inode)->xattr_sem);
989 no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND;
990 EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
991
992 error = ext4_get_inode_loc(inode, &is.iloc);
993 if (error)
994 goto cleanup;
995
996 error = ext4_journal_get_write_access(handle, is.iloc.bh);
997 if (error)
998 goto cleanup;
999
1000 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
1001 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1002 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1003 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
1004 }
1005
1006 error = ext4_xattr_ibody_find(inode, &i, &is);
1007 if (error)
1008 goto cleanup;
1009 if (is.s.not_found)
1010 error = ext4_xattr_block_find(inode, &i, &bs);
1011 if (error)
1012 goto cleanup;
1013 if (is.s.not_found && bs.s.not_found) {
1014 error = -ENODATA;
1015 if (flags & XATTR_REPLACE)
1016 goto cleanup;
1017 error = 0;
1018 if (!value)
1019 goto cleanup;
1020 } else {
1021 error = -EEXIST;
1022 if (flags & XATTR_CREATE)
1023 goto cleanup;
1024 }
1025 if (!value) {
1026 if (!is.s.not_found)
1027 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1028 else if (!bs.s.not_found)
1029 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1030 } else {
1031 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1032 if (!error && !bs.s.not_found) {
1033 i.value = NULL;
1034 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1035 } else if (error == -ENOSPC) {
1036 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1037 error = ext4_xattr_block_find(inode, &i, &bs);
1038 if (error)
1039 goto cleanup;
1040 }
1041 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1042 if (error)
1043 goto cleanup;
1044 if (!is.s.not_found) {
1045 i.value = NULL;
1046 error = ext4_xattr_ibody_set(handle, inode, &i,
1047 &is);
1048 }
1049 }
1050 }
1051 if (!error) {
1052 ext4_xattr_update_super_block(handle, inode->i_sb);
1053 inode->i_ctime = ext4_current_time(inode);
1054 if (!value)
1055 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1056 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1057 /*
1058 * The bh is consumed by ext4_mark_iloc_dirty, even with
1059 * error != 0.
1060 */
1061 is.iloc.bh = NULL;
1062 if (IS_SYNC(inode))
1063 ext4_handle_sync(handle);
1064 }
1065
1066 cleanup:
1067 brelse(is.iloc.bh);
1068 brelse(bs.bh);
1069 if (no_expand == 0)
1070 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1071 up_write(&EXT4_I(inode)->xattr_sem);
1072 return error;
1073 }
1074
1075 /*
1076 * ext4_xattr_set()
1077 *
1078 * Like ext4_xattr_set_handle, but start from an inode. This extended
1079 * attribute modification is a filesystem transaction by itself.
1080 *
1081 * Returns 0, or a negative error number on failure.
1082 */
1083 int
1084 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1085 const void *value, size_t value_len, int flags)
1086 {
1087 handle_t *handle;
1088 int error, retries = 0;
1089
1090 retry:
1091 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1092 if (IS_ERR(handle)) {
1093 error = PTR_ERR(handle);
1094 } else {
1095 int error2;
1096
1097 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1098 value, value_len, flags);
1099 error2 = ext4_journal_stop(handle);
1100 if (error == -ENOSPC &&
1101 ext4_should_retry_alloc(inode->i_sb, &retries))
1102 goto retry;
1103 if (error == 0)
1104 error = error2;
1105 }
1106
1107 return error;
1108 }
1109
1110 /*
1111 * Shift the EA entries in the inode to create space for the increased
1112 * i_extra_isize.
1113 */
1114 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1115 int value_offs_shift, void *to,
1116 void *from, size_t n, int blocksize)
1117 {
1118 struct ext4_xattr_entry *last = entry;
1119 int new_offs;
1120
1121 /* Adjust the value offsets of the entries */
1122 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1123 if (!last->e_value_block && last->e_value_size) {
1124 new_offs = le16_to_cpu(last->e_value_offs) +
1125 value_offs_shift;
1126 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1127 > blocksize);
1128 last->e_value_offs = cpu_to_le16(new_offs);
1129 }
1130 }
1131 /* Shift the entries by n bytes */
1132 memmove(to, from, n);
1133 }
1134
1135 /*
1136 * Expand an inode by new_extra_isize bytes when EAs are present.
1137 * Returns 0 on success or negative error number on failure.
1138 */
1139 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1140 struct ext4_inode *raw_inode, handle_t *handle)
1141 {
1142 struct ext4_xattr_ibody_header *header;
1143 struct ext4_xattr_entry *entry, *last, *first;
1144 struct buffer_head *bh = NULL;
1145 struct ext4_xattr_ibody_find *is = NULL;
1146 struct ext4_xattr_block_find *bs = NULL;
1147 char *buffer = NULL, *b_entry_name = NULL;
1148 size_t min_offs, free;
1149 int total_ino, total_blk;
1150 void *base, *start, *end;
1151 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1152 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1153
1154 down_write(&EXT4_I(inode)->xattr_sem);
1155 retry:
1156 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1157 up_write(&EXT4_I(inode)->xattr_sem);
1158 return 0;
1159 }
1160
1161 header = IHDR(inode, raw_inode);
1162 entry = IFIRST(header);
1163
1164 /*
1165 * Check if enough free space is available in the inode to shift the
1166 * entries ahead by new_extra_isize.
1167 */
1168
1169 base = start = entry;
1170 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1171 min_offs = end - base;
1172 last = entry;
1173 total_ino = sizeof(struct ext4_xattr_ibody_header);
1174
1175 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1176 if (free >= new_extra_isize) {
1177 entry = IFIRST(header);
1178 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1179 - new_extra_isize, (void *)raw_inode +
1180 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1181 (void *)header, total_ino,
1182 inode->i_sb->s_blocksize);
1183 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1184 error = 0;
1185 goto cleanup;
1186 }
1187
1188 /*
1189 * Enough free space isn't available in the inode, check if
1190 * EA block can hold new_extra_isize bytes.
1191 */
1192 if (EXT4_I(inode)->i_file_acl) {
1193 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1194 error = -EIO;
1195 if (!bh)
1196 goto cleanup;
1197 if (ext4_xattr_check_block(bh)) {
1198 ext4_error(inode->i_sb, __func__,
1199 "inode %lu: bad block %llu", inode->i_ino,
1200 EXT4_I(inode)->i_file_acl);
1201 error = -EIO;
1202 goto cleanup;
1203 }
1204 base = BHDR(bh);
1205 first = BFIRST(bh);
1206 end = bh->b_data + bh->b_size;
1207 min_offs = end - base;
1208 free = ext4_xattr_free_space(first, &min_offs, base,
1209 &total_blk);
1210 if (free < new_extra_isize) {
1211 if (!tried_min_extra_isize && s_min_extra_isize) {
1212 tried_min_extra_isize++;
1213 new_extra_isize = s_min_extra_isize;
1214 brelse(bh);
1215 goto retry;
1216 }
1217 error = -1;
1218 goto cleanup;
1219 }
1220 } else {
1221 free = inode->i_sb->s_blocksize;
1222 }
1223
1224 while (new_extra_isize > 0) {
1225 size_t offs, size, entry_size;
1226 struct ext4_xattr_entry *small_entry = NULL;
1227 struct ext4_xattr_info i = {
1228 .value = NULL,
1229 .value_len = 0,
1230 };
1231 unsigned int total_size; /* EA entry size + value size */
1232 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1233 unsigned int min_total_size = ~0U;
1234
1235 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1236 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1237 if (!is || !bs) {
1238 error = -ENOMEM;
1239 goto cleanup;
1240 }
1241
1242 is->s.not_found = -ENODATA;
1243 bs->s.not_found = -ENODATA;
1244 is->iloc.bh = NULL;
1245 bs->bh = NULL;
1246
1247 last = IFIRST(header);
1248 /* Find the entry best suited to be pushed into EA block */
1249 entry = NULL;
1250 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1251 total_size =
1252 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1253 EXT4_XATTR_LEN(last->e_name_len);
1254 if (total_size <= free && total_size < min_total_size) {
1255 if (total_size < new_extra_isize) {
1256 small_entry = last;
1257 } else {
1258 entry = last;
1259 min_total_size = total_size;
1260 }
1261 }
1262 }
1263
1264 if (entry == NULL) {
1265 if (small_entry) {
1266 entry = small_entry;
1267 } else {
1268 if (!tried_min_extra_isize &&
1269 s_min_extra_isize) {
1270 tried_min_extra_isize++;
1271 new_extra_isize = s_min_extra_isize;
1272 goto retry;
1273 }
1274 error = -1;
1275 goto cleanup;
1276 }
1277 }
1278 offs = le16_to_cpu(entry->e_value_offs);
1279 size = le32_to_cpu(entry->e_value_size);
1280 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1281 i.name_index = entry->e_name_index,
1282 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1283 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1284 if (!buffer || !b_entry_name) {
1285 error = -ENOMEM;
1286 goto cleanup;
1287 }
1288 /* Save the entry name and the entry value */
1289 memcpy(buffer, (void *)IFIRST(header) + offs,
1290 EXT4_XATTR_SIZE(size));
1291 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1292 b_entry_name[entry->e_name_len] = '\0';
1293 i.name = b_entry_name;
1294
1295 error = ext4_get_inode_loc(inode, &is->iloc);
1296 if (error)
1297 goto cleanup;
1298
1299 error = ext4_xattr_ibody_find(inode, &i, is);
1300 if (error)
1301 goto cleanup;
1302
1303 /* Remove the chosen entry from the inode */
1304 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1305
1306 entry = IFIRST(header);
1307 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1308 shift_bytes = new_extra_isize;
1309 else
1310 shift_bytes = entry_size + size;
1311 /* Adjust the offsets and shift the remaining entries ahead */
1312 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1313 shift_bytes, (void *)raw_inode +
1314 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1315 (void *)header, total_ino - entry_size,
1316 inode->i_sb->s_blocksize);
1317
1318 extra_isize += shift_bytes;
1319 new_extra_isize -= shift_bytes;
1320 EXT4_I(inode)->i_extra_isize = extra_isize;
1321
1322 i.name = b_entry_name;
1323 i.value = buffer;
1324 i.value_len = size;
1325 error = ext4_xattr_block_find(inode, &i, bs);
1326 if (error)
1327 goto cleanup;
1328
1329 /* Add entry which was removed from the inode into the block */
1330 error = ext4_xattr_block_set(handle, inode, &i, bs);
1331 if (error)
1332 goto cleanup;
1333 kfree(b_entry_name);
1334 kfree(buffer);
1335 b_entry_name = NULL;
1336 buffer = NULL;
1337 brelse(is->iloc.bh);
1338 kfree(is);
1339 kfree(bs);
1340 }
1341 brelse(bh);
1342 up_write(&EXT4_I(inode)->xattr_sem);
1343 return 0;
1344
1345 cleanup:
1346 kfree(b_entry_name);
1347 kfree(buffer);
1348 if (is)
1349 brelse(is->iloc.bh);
1350 kfree(is);
1351 kfree(bs);
1352 brelse(bh);
1353 up_write(&EXT4_I(inode)->xattr_sem);
1354 return error;
1355 }
1356
1357
1358
1359 /*
1360 * ext4_xattr_delete_inode()
1361 *
1362 * Free extended attribute resources associated with this inode. This
1363 * is called immediately before an inode is freed. We have exclusive
1364 * access to the inode.
1365 */
1366 void
1367 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1368 {
1369 struct buffer_head *bh = NULL;
1370
1371 if (!EXT4_I(inode)->i_file_acl)
1372 goto cleanup;
1373 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1374 if (!bh) {
1375 ext4_error(inode->i_sb, __func__,
1376 "inode %lu: block %llu read error", inode->i_ino,
1377 EXT4_I(inode)->i_file_acl);
1378 goto cleanup;
1379 }
1380 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1381 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1382 ext4_error(inode->i_sb, __func__,
1383 "inode %lu: bad block %llu", inode->i_ino,
1384 EXT4_I(inode)->i_file_acl);
1385 goto cleanup;
1386 }
1387 ext4_xattr_release_block(handle, inode, bh);
1388 EXT4_I(inode)->i_file_acl = 0;
1389
1390 cleanup:
1391 brelse(bh);
1392 }
1393
1394 /*
1395 * ext4_xattr_put_super()
1396 *
1397 * This is called when a file system is unmounted.
1398 */
1399 void
1400 ext4_xattr_put_super(struct super_block *sb)
1401 {
1402 mb_cache_shrink(sb->s_bdev);
1403 }
1404
1405 /*
1406 * ext4_xattr_cache_insert()
1407 *
1408 * Create a new entry in the extended attribute cache, and insert
1409 * it unless such an entry is already in the cache.
1410 *
1411 * Returns 0, or a negative error number on failure.
1412 */
1413 static void
1414 ext4_xattr_cache_insert(struct buffer_head *bh)
1415 {
1416 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1417 struct mb_cache_entry *ce;
1418 int error;
1419
1420 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1421 if (!ce) {
1422 ea_bdebug(bh, "out of memory");
1423 return;
1424 }
1425 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1426 if (error) {
1427 mb_cache_entry_free(ce);
1428 if (error == -EBUSY) {
1429 ea_bdebug(bh, "already in cache");
1430 error = 0;
1431 }
1432 } else {
1433 ea_bdebug(bh, "inserting [%x]", (int)hash);
1434 mb_cache_entry_release(ce);
1435 }
1436 }
1437
1438 /*
1439 * ext4_xattr_cmp()
1440 *
1441 * Compare two extended attribute blocks for equality.
1442 *
1443 * Returns 0 if the blocks are equal, 1 if they differ, and
1444 * a negative error number on errors.
1445 */
1446 static int
1447 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1448 struct ext4_xattr_header *header2)
1449 {
1450 struct ext4_xattr_entry *entry1, *entry2;
1451
1452 entry1 = ENTRY(header1+1);
1453 entry2 = ENTRY(header2+1);
1454 while (!IS_LAST_ENTRY(entry1)) {
1455 if (IS_LAST_ENTRY(entry2))
1456 return 1;
1457 if (entry1->e_hash != entry2->e_hash ||
1458 entry1->e_name_index != entry2->e_name_index ||
1459 entry1->e_name_len != entry2->e_name_len ||
1460 entry1->e_value_size != entry2->e_value_size ||
1461 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1462 return 1;
1463 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1464 return -EIO;
1465 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1466 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1467 le32_to_cpu(entry1->e_value_size)))
1468 return 1;
1469
1470 entry1 = EXT4_XATTR_NEXT(entry1);
1471 entry2 = EXT4_XATTR_NEXT(entry2);
1472 }
1473 if (!IS_LAST_ENTRY(entry2))
1474 return 1;
1475 return 0;
1476 }
1477
1478 /*
1479 * ext4_xattr_cache_find()
1480 *
1481 * Find an identical extended attribute block.
1482 *
1483 * Returns a pointer to the block found, or NULL if such a block was
1484 * not found or an error occurred.
1485 */
1486 static struct buffer_head *
1487 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1488 struct mb_cache_entry **pce)
1489 {
1490 __u32 hash = le32_to_cpu(header->h_hash);
1491 struct mb_cache_entry *ce;
1492
1493 if (!header->h_hash)
1494 return NULL; /* never share */
1495 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1496 again:
1497 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1498 inode->i_sb->s_bdev, hash);
1499 while (ce) {
1500 struct buffer_head *bh;
1501
1502 if (IS_ERR(ce)) {
1503 if (PTR_ERR(ce) == -EAGAIN)
1504 goto again;
1505 break;
1506 }
1507 bh = sb_bread(inode->i_sb, ce->e_block);
1508 if (!bh) {
1509 ext4_error(inode->i_sb, __func__,
1510 "inode %lu: block %lu read error",
1511 inode->i_ino, (unsigned long) ce->e_block);
1512 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1513 EXT4_XATTR_REFCOUNT_MAX) {
1514 ea_idebug(inode, "block %lu refcount %d>=%d",
1515 (unsigned long) ce->e_block,
1516 le32_to_cpu(BHDR(bh)->h_refcount),
1517 EXT4_XATTR_REFCOUNT_MAX);
1518 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1519 *pce = ce;
1520 return bh;
1521 }
1522 brelse(bh);
1523 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1524 }
1525 return NULL;
1526 }
1527
1528 #define NAME_HASH_SHIFT 5
1529 #define VALUE_HASH_SHIFT 16
1530
1531 /*
1532 * ext4_xattr_hash_entry()
1533 *
1534 * Compute the hash of an extended attribute.
1535 */
1536 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1537 struct ext4_xattr_entry *entry)
1538 {
1539 __u32 hash = 0;
1540 char *name = entry->e_name;
1541 int n;
1542
1543 for (n = 0; n < entry->e_name_len; n++) {
1544 hash = (hash << NAME_HASH_SHIFT) ^
1545 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1546 *name++;
1547 }
1548
1549 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1550 __le32 *value = (__le32 *)((char *)header +
1551 le16_to_cpu(entry->e_value_offs));
1552 for (n = (le32_to_cpu(entry->e_value_size) +
1553 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1554 hash = (hash << VALUE_HASH_SHIFT) ^
1555 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1556 le32_to_cpu(*value++);
1557 }
1558 }
1559 entry->e_hash = cpu_to_le32(hash);
1560 }
1561
1562 #undef NAME_HASH_SHIFT
1563 #undef VALUE_HASH_SHIFT
1564
1565 #define BLOCK_HASH_SHIFT 16
1566
1567 /*
1568 * ext4_xattr_rehash()
1569 *
1570 * Re-compute the extended attribute hash value after an entry has changed.
1571 */
1572 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1573 struct ext4_xattr_entry *entry)
1574 {
1575 struct ext4_xattr_entry *here;
1576 __u32 hash = 0;
1577
1578 ext4_xattr_hash_entry(header, entry);
1579 here = ENTRY(header+1);
1580 while (!IS_LAST_ENTRY(here)) {
1581 if (!here->e_hash) {
1582 /* Block is not shared if an entry's hash value == 0 */
1583 hash = 0;
1584 break;
1585 }
1586 hash = (hash << BLOCK_HASH_SHIFT) ^
1587 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1588 le32_to_cpu(here->e_hash);
1589 here = EXT4_XATTR_NEXT(here);
1590 }
1591 header->h_hash = cpu_to_le32(hash);
1592 }
1593
1594 #undef BLOCK_HASH_SHIFT
1595
1596 int __init
1597 init_ext4_xattr(void)
1598 {
1599 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1600 sizeof(struct mb_cache_entry) +
1601 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1602 if (!ext4_xattr_cache)
1603 return -ENOMEM;
1604 return 0;
1605 }
1606
1607 void
1608 exit_ext4_xattr(void)
1609 {
1610 if (ext4_xattr_cache)
1611 mb_cache_destroy(ext4_xattr_cache);
1612 ext4_xattr_cache = NULL;
1613 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree