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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(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
86# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
87#endif
88
89static void ext4_xattr_cache_insert(struct buffer_head *);
90static struct buffer_head *ext4_xattr_cache_find(struct inode *,
91 struct ext4_xattr_header *,
92 struct mb_cache_entry **);
93static void ext4_xattr_rehash(struct ext4_xattr_header *,
94 struct ext4_xattr_entry *);
95static int ext4_xattr_list(struct dentry *dentry, char *buffer,
96 size_t buffer_size);
97
98static struct mb_cache *ext4_xattr_cache;
99
100static const 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
112const 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
125static __le32 ext4_xattr_block_csum(struct inode *inode,
126 sector_t block_nr,
127 struct ext4_xattr_header *hdr)
128{
129 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
130 __u32 csum, old;
131
132 old = hdr->h_checksum;
133 hdr->h_checksum = 0;
134 block_nr = cpu_to_le64(block_nr);
135 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&block_nr,
136 sizeof(block_nr));
137 csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
138 EXT4_BLOCK_SIZE(inode->i_sb));
139
140 hdr->h_checksum = old;
141 return cpu_to_le32(csum);
142}
143
144static int ext4_xattr_block_csum_verify(struct inode *inode,
145 sector_t block_nr,
146 struct ext4_xattr_header *hdr)
147{
148 if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
149 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
150 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
151 return 0;
152 return 1;
153}
154
155static void ext4_xattr_block_csum_set(struct inode *inode,
156 sector_t block_nr,
157 struct ext4_xattr_header *hdr)
158{
159 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
160 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
161 return;
162
163 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
164}
165
166static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
167 struct inode *inode,
168 struct buffer_head *bh)
169{
170 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
171 return ext4_handle_dirty_metadata(handle, inode, bh);
172}
173
174static inline const struct xattr_handler *
175ext4_xattr_handler(int name_index)
176{
177 const struct xattr_handler *handler = NULL;
178
179 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
180 handler = ext4_xattr_handler_map[name_index];
181 return handler;
182}
183
184/*
185 * Inode operation listxattr()
186 *
187 * dentry->d_inode->i_mutex: don't care
188 */
189ssize_t
190ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
191{
192 return ext4_xattr_list(dentry, buffer, size);
193}
194
195static int
196ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
197{
198 while (!IS_LAST_ENTRY(entry)) {
199 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
200 if ((void *)next >= end)
201 return -EIO;
202 entry = next;
203 }
204 return 0;
205}
206
207static inline int
208ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
209{
210 int error;
211
212 if (buffer_verified(bh))
213 return 0;
214
215 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
216 BHDR(bh)->h_blocks != cpu_to_le32(1))
217 return -EIO;
218 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
219 return -EIO;
220 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
221 if (!error)
222 set_buffer_verified(bh);
223 return error;
224}
225
226static inline int
227ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
228{
229 size_t value_size = le32_to_cpu(entry->e_value_size);
230
231 if (entry->e_value_block != 0 || value_size > size ||
232 le16_to_cpu(entry->e_value_offs) + value_size > size)
233 return -EIO;
234 return 0;
235}
236
237static int
238ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
239 const char *name, size_t size, int sorted)
240{
241 struct ext4_xattr_entry *entry;
242 size_t name_len;
243 int cmp = 1;
244
245 if (name == NULL)
246 return -EINVAL;
247 name_len = strlen(name);
248 entry = *pentry;
249 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
250 cmp = name_index - entry->e_name_index;
251 if (!cmp)
252 cmp = name_len - entry->e_name_len;
253 if (!cmp)
254 cmp = memcmp(name, entry->e_name, name_len);
255 if (cmp <= 0 && (sorted || cmp == 0))
256 break;
257 }
258 *pentry = entry;
259 if (!cmp && ext4_xattr_check_entry(entry, size))
260 return -EIO;
261 return cmp ? -ENODATA : 0;
262}
263
264static int
265ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
266 void *buffer, size_t buffer_size)
267{
268 struct buffer_head *bh = NULL;
269 struct ext4_xattr_entry *entry;
270 size_t size;
271 int error;
272
273 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
274 name_index, name, buffer, (long)buffer_size);
275
276 error = -ENODATA;
277 if (!EXT4_I(inode)->i_file_acl)
278 goto cleanup;
279 ea_idebug(inode, "reading block %llu",
280 (unsigned long long)EXT4_I(inode)->i_file_acl);
281 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
282 if (!bh)
283 goto cleanup;
284 ea_bdebug(bh, "b_count=%d, refcount=%d",
285 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
286 if (ext4_xattr_check_block(inode, bh)) {
287bad_block:
288 EXT4_ERROR_INODE(inode, "bad block %llu",
289 EXT4_I(inode)->i_file_acl);
290 error = -EIO;
291 goto cleanup;
292 }
293 ext4_xattr_cache_insert(bh);
294 entry = BFIRST(bh);
295 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
296 if (error == -EIO)
297 goto bad_block;
298 if (error)
299 goto cleanup;
300 size = le32_to_cpu(entry->e_value_size);
301 if (buffer) {
302 error = -ERANGE;
303 if (size > buffer_size)
304 goto cleanup;
305 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
306 size);
307 }
308 error = size;
309
310cleanup:
311 brelse(bh);
312 return error;
313}
314
315static int
316ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
317 void *buffer, size_t buffer_size)
318{
319 struct ext4_xattr_ibody_header *header;
320 struct ext4_xattr_entry *entry;
321 struct ext4_inode *raw_inode;
322 struct ext4_iloc iloc;
323 size_t size;
324 void *end;
325 int error;
326
327 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
328 return -ENODATA;
329 error = ext4_get_inode_loc(inode, &iloc);
330 if (error)
331 return error;
332 raw_inode = ext4_raw_inode(&iloc);
333 header = IHDR(inode, raw_inode);
334 entry = IFIRST(header);
335 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
336 error = ext4_xattr_check_names(entry, end);
337 if (error)
338 goto cleanup;
339 error = ext4_xattr_find_entry(&entry, name_index, name,
340 end - (void *)entry, 0);
341 if (error)
342 goto cleanup;
343 size = le32_to_cpu(entry->e_value_size);
344 if (buffer) {
345 error = -ERANGE;
346 if (size > buffer_size)
347 goto cleanup;
348 memcpy(buffer, (void *)IFIRST(header) +
349 le16_to_cpu(entry->e_value_offs), size);
350 }
351 error = size;
352
353cleanup:
354 brelse(iloc.bh);
355 return error;
356}
357
358/*
359 * ext4_xattr_get()
360 *
361 * Copy an extended attribute into the buffer
362 * provided, or compute the buffer size required.
363 * Buffer is NULL to compute the size of the buffer required.
364 *
365 * Returns a negative error number on failure, or the number of bytes
366 * used / required on success.
367 */
368int
369ext4_xattr_get(struct inode *inode, int name_index, const char *name,
370 void *buffer, size_t buffer_size)
371{
372 int error;
373
374 down_read(&EXT4_I(inode)->xattr_sem);
375 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
376 buffer_size);
377 if (error == -ENODATA)
378 error = ext4_xattr_block_get(inode, name_index, name, buffer,
379 buffer_size);
380 up_read(&EXT4_I(inode)->xattr_sem);
381 return error;
382}
383
384static int
385ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
386 char *buffer, size_t buffer_size)
387{
388 size_t rest = buffer_size;
389
390 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
391 const struct xattr_handler *handler =
392 ext4_xattr_handler(entry->e_name_index);
393
394 if (handler) {
395 size_t size = handler->list(dentry, buffer, rest,
396 entry->e_name,
397 entry->e_name_len,
398 handler->flags);
399 if (buffer) {
400 if (size > rest)
401 return -ERANGE;
402 buffer += size;
403 }
404 rest -= size;
405 }
406 }
407 return buffer_size - rest;
408}
409
410static int
411ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
412{
413 struct inode *inode = dentry->d_inode;
414 struct buffer_head *bh = NULL;
415 int error;
416
417 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
418 buffer, (long)buffer_size);
419
420 error = 0;
421 if (!EXT4_I(inode)->i_file_acl)
422 goto cleanup;
423 ea_idebug(inode, "reading block %llu",
424 (unsigned long long)EXT4_I(inode)->i_file_acl);
425 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
426 error = -EIO;
427 if (!bh)
428 goto cleanup;
429 ea_bdebug(bh, "b_count=%d, refcount=%d",
430 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
431 if (ext4_xattr_check_block(inode, bh)) {
432 EXT4_ERROR_INODE(inode, "bad block %llu",
433 EXT4_I(inode)->i_file_acl);
434 error = -EIO;
435 goto cleanup;
436 }
437 ext4_xattr_cache_insert(bh);
438 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
439
440cleanup:
441 brelse(bh);
442
443 return error;
444}
445
446static int
447ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
448{
449 struct inode *inode = dentry->d_inode;
450 struct ext4_xattr_ibody_header *header;
451 struct ext4_inode *raw_inode;
452 struct ext4_iloc iloc;
453 void *end;
454 int error;
455
456 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
457 return 0;
458 error = ext4_get_inode_loc(inode, &iloc);
459 if (error)
460 return error;
461 raw_inode = ext4_raw_inode(&iloc);
462 header = IHDR(inode, raw_inode);
463 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
464 error = ext4_xattr_check_names(IFIRST(header), end);
465 if (error)
466 goto cleanup;
467 error = ext4_xattr_list_entries(dentry, IFIRST(header),
468 buffer, buffer_size);
469
470cleanup:
471 brelse(iloc.bh);
472 return error;
473}
474
475/*
476 * ext4_xattr_list()
477 *
478 * Copy a list of attribute names into the buffer
479 * provided, or compute the buffer size required.
480 * Buffer is NULL to compute the size of the buffer required.
481 *
482 * Returns a negative error number on failure, or the number of bytes
483 * used / required on success.
484 */
485static int
486ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
487{
488 int ret, ret2;
489
490 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
491 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
492 if (ret < 0)
493 goto errout;
494 if (buffer) {
495 buffer += ret;
496 buffer_size -= ret;
497 }
498 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
499 if (ret < 0)
500 goto errout;
501 ret += ret2;
502errout:
503 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
504 return ret;
505}
506
507/*
508 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
509 * not set, set it.
510 */
511static void ext4_xattr_update_super_block(handle_t *handle,
512 struct super_block *sb)
513{
514 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
515 return;
516
517 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
518 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
519 ext4_handle_dirty_super(handle, sb);
520 }
521}
522
523/*
524 * Release the xattr block BH: If the reference count is > 1, decrement
525 * it; otherwise free the block.
526 */
527static void
528ext4_xattr_release_block(handle_t *handle, struct inode *inode,
529 struct buffer_head *bh)
530{
531 struct mb_cache_entry *ce = NULL;
532 int error = 0;
533
534 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
535 error = ext4_journal_get_write_access(handle, bh);
536 if (error)
537 goto out;
538
539 lock_buffer(bh);
540 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
541 ea_bdebug(bh, "refcount now=0; freeing");
542 if (ce)
543 mb_cache_entry_free(ce);
544 get_bh(bh);
545 ext4_free_blocks(handle, inode, bh, 0, 1,
546 EXT4_FREE_BLOCKS_METADATA |
547 EXT4_FREE_BLOCKS_FORGET);
548 unlock_buffer(bh);
549 } else {
550 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
551 if (ce)
552 mb_cache_entry_release(ce);
553 unlock_buffer(bh);
554 error = ext4_handle_dirty_xattr_block(handle, inode, bh);
555 if (IS_SYNC(inode))
556 ext4_handle_sync(handle);
557 dquot_free_block(inode, 1);
558 ea_bdebug(bh, "refcount now=%d; releasing",
559 le32_to_cpu(BHDR(bh)->h_refcount));
560 }
561out:
562 ext4_std_error(inode->i_sb, error);
563 return;
564}
565
566/*
567 * Find the available free space for EAs. This also returns the total number of
568 * bytes used by EA entries.
569 */
570static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
571 size_t *min_offs, void *base, int *total)
572{
573 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
574 *total += EXT4_XATTR_LEN(last->e_name_len);
575 if (!last->e_value_block && last->e_value_size) {
576 size_t offs = le16_to_cpu(last->e_value_offs);
577 if (offs < *min_offs)
578 *min_offs = offs;
579 }
580 }
581 return (*min_offs - ((void *)last - base) - sizeof(__u32));
582}
583
584struct ext4_xattr_info {
585 int name_index;
586 const char *name;
587 const void *value;
588 size_t value_len;
589};
590
591struct ext4_xattr_search {
592 struct ext4_xattr_entry *first;
593 void *base;
594 void *end;
595 struct ext4_xattr_entry *here;
596 int not_found;
597};
598
599static int
600ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
601{
602 struct ext4_xattr_entry *last;
603 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
604
605 /* Compute min_offs and last. */
606 last = s->first;
607 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
608 if (!last->e_value_block && last->e_value_size) {
609 size_t offs = le16_to_cpu(last->e_value_offs);
610 if (offs < min_offs)
611 min_offs = offs;
612 }
613 }
614 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
615 if (!s->not_found) {
616 if (!s->here->e_value_block && s->here->e_value_size) {
617 size_t size = le32_to_cpu(s->here->e_value_size);
618 free += EXT4_XATTR_SIZE(size);
619 }
620 free += EXT4_XATTR_LEN(name_len);
621 }
622 if (i->value) {
623 if (free < EXT4_XATTR_SIZE(i->value_len) ||
624 free < EXT4_XATTR_LEN(name_len) +
625 EXT4_XATTR_SIZE(i->value_len))
626 return -ENOSPC;
627 }
628
629 if (i->value && s->not_found) {
630 /* Insert the new name. */
631 size_t size = EXT4_XATTR_LEN(name_len);
632 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
633 memmove((void *)s->here + size, s->here, rest);
634 memset(s->here, 0, size);
635 s->here->e_name_index = i->name_index;
636 s->here->e_name_len = name_len;
637 memcpy(s->here->e_name, i->name, name_len);
638 } else {
639 if (!s->here->e_value_block && s->here->e_value_size) {
640 void *first_val = s->base + min_offs;
641 size_t offs = le16_to_cpu(s->here->e_value_offs);
642 void *val = s->base + offs;
643 size_t size = EXT4_XATTR_SIZE(
644 le32_to_cpu(s->here->e_value_size));
645
646 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
647 /* The old and the new value have the same
648 size. Just replace. */
649 s->here->e_value_size =
650 cpu_to_le32(i->value_len);
651 memset(val + size - EXT4_XATTR_PAD, 0,
652 EXT4_XATTR_PAD); /* Clear pad bytes. */
653 memcpy(val, i->value, i->value_len);
654 return 0;
655 }
656
657 /* Remove the old value. */
658 memmove(first_val + size, first_val, val - first_val);
659 memset(first_val, 0, size);
660 s->here->e_value_size = 0;
661 s->here->e_value_offs = 0;
662 min_offs += size;
663
664 /* Adjust all value offsets. */
665 last = s->first;
666 while (!IS_LAST_ENTRY(last)) {
667 size_t o = le16_to_cpu(last->e_value_offs);
668 if (!last->e_value_block &&
669 last->e_value_size && o < offs)
670 last->e_value_offs =
671 cpu_to_le16(o + size);
672 last = EXT4_XATTR_NEXT(last);
673 }
674 }
675 if (!i->value) {
676 /* Remove the old name. */
677 size_t size = EXT4_XATTR_LEN(name_len);
678 last = ENTRY((void *)last - size);
679 memmove(s->here, (void *)s->here + size,
680 (void *)last - (void *)s->here + sizeof(__u32));
681 memset(last, 0, size);
682 }
683 }
684
685 if (i->value) {
686 /* Insert the new value. */
687 s->here->e_value_size = cpu_to_le32(i->value_len);
688 if (i->value_len) {
689 size_t size = EXT4_XATTR_SIZE(i->value_len);
690 void *val = s->base + min_offs - size;
691 s->here->e_value_offs = cpu_to_le16(min_offs - size);
692 memset(val + size - EXT4_XATTR_PAD, 0,
693 EXT4_XATTR_PAD); /* Clear the pad bytes. */
694 memcpy(val, i->value, i->value_len);
695 }
696 }
697 return 0;
698}
699
700struct ext4_xattr_block_find {
701 struct ext4_xattr_search s;
702 struct buffer_head *bh;
703};
704
705static int
706ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
707 struct ext4_xattr_block_find *bs)
708{
709 struct super_block *sb = inode->i_sb;
710 int error;
711
712 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
713 i->name_index, i->name, i->value, (long)i->value_len);
714
715 if (EXT4_I(inode)->i_file_acl) {
716 /* The inode already has an extended attribute block. */
717 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
718 error = -EIO;
719 if (!bs->bh)
720 goto cleanup;
721 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
722 atomic_read(&(bs->bh->b_count)),
723 le32_to_cpu(BHDR(bs->bh)->h_refcount));
724 if (ext4_xattr_check_block(inode, bs->bh)) {
725 EXT4_ERROR_INODE(inode, "bad block %llu",
726 EXT4_I(inode)->i_file_acl);
727 error = -EIO;
728 goto cleanup;
729 }
730 /* Find the named attribute. */
731 bs->s.base = BHDR(bs->bh);
732 bs->s.first = BFIRST(bs->bh);
733 bs->s.end = bs->bh->b_data + bs->bh->b_size;
734 bs->s.here = bs->s.first;
735 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
736 i->name, bs->bh->b_size, 1);
737 if (error && error != -ENODATA)
738 goto cleanup;
739 bs->s.not_found = error;
740 }
741 error = 0;
742
743cleanup:
744 return error;
745}
746
747static int
748ext4_xattr_block_set(handle_t *handle, struct inode *inode,
749 struct ext4_xattr_info *i,
750 struct ext4_xattr_block_find *bs)
751{
752 struct super_block *sb = inode->i_sb;
753 struct buffer_head *new_bh = NULL;
754 struct ext4_xattr_search *s = &bs->s;
755 struct mb_cache_entry *ce = NULL;
756 int error = 0;
757
758#define header(x) ((struct ext4_xattr_header *)(x))
759
760 if (i->value && i->value_len > sb->s_blocksize)
761 return -ENOSPC;
762 if (s->base) {
763 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
764 bs->bh->b_blocknr);
765 error = ext4_journal_get_write_access(handle, bs->bh);
766 if (error)
767 goto cleanup;
768 lock_buffer(bs->bh);
769
770 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
771 if (ce) {
772 mb_cache_entry_free(ce);
773 ce = NULL;
774 }
775 ea_bdebug(bs->bh, "modifying in-place");
776 error = ext4_xattr_set_entry(i, s);
777 if (!error) {
778 if (!IS_LAST_ENTRY(s->first))
779 ext4_xattr_rehash(header(s->base),
780 s->here);
781 ext4_xattr_cache_insert(bs->bh);
782 }
783 unlock_buffer(bs->bh);
784 if (error == -EIO)
785 goto bad_block;
786 if (!error)
787 error = ext4_handle_dirty_xattr_block(handle,
788 inode,
789 bs->bh);
790 if (error)
791 goto cleanup;
792 goto inserted;
793 } else {
794 int offset = (char *)s->here - bs->bh->b_data;
795
796 unlock_buffer(bs->bh);
797 ext4_handle_release_buffer(handle, bs->bh);
798 if (ce) {
799 mb_cache_entry_release(ce);
800 ce = NULL;
801 }
802 ea_bdebug(bs->bh, "cloning");
803 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
804 error = -ENOMEM;
805 if (s->base == NULL)
806 goto cleanup;
807 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
808 s->first = ENTRY(header(s->base)+1);
809 header(s->base)->h_refcount = cpu_to_le32(1);
810 s->here = ENTRY(s->base + offset);
811 s->end = s->base + bs->bh->b_size;
812 }
813 } else {
814 /* Allocate a buffer where we construct the new block. */
815 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
816 /* assert(header == s->base) */
817 error = -ENOMEM;
818 if (s->base == NULL)
819 goto cleanup;
820 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
821 header(s->base)->h_blocks = cpu_to_le32(1);
822 header(s->base)->h_refcount = cpu_to_le32(1);
823 s->first = ENTRY(header(s->base)+1);
824 s->here = ENTRY(header(s->base)+1);
825 s->end = s->base + sb->s_blocksize;
826 }
827
828 error = ext4_xattr_set_entry(i, s);
829 if (error == -EIO)
830 goto bad_block;
831 if (error)
832 goto cleanup;
833 if (!IS_LAST_ENTRY(s->first))
834 ext4_xattr_rehash(header(s->base), s->here);
835
836inserted:
837 if (!IS_LAST_ENTRY(s->first)) {
838 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
839 if (new_bh) {
840 /* We found an identical block in the cache. */
841 if (new_bh == bs->bh)
842 ea_bdebug(new_bh, "keeping");
843 else {
844 /* The old block is released after updating
845 the inode. */
846 error = dquot_alloc_block(inode, 1);
847 if (error)
848 goto cleanup;
849 error = ext4_journal_get_write_access(handle,
850 new_bh);
851 if (error)
852 goto cleanup_dquot;
853 lock_buffer(new_bh);
854 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
855 ea_bdebug(new_bh, "reusing; refcount now=%d",
856 le32_to_cpu(BHDR(new_bh)->h_refcount));
857 unlock_buffer(new_bh);
858 error = ext4_handle_dirty_xattr_block(handle,
859 inode,
860 new_bh);
861 if (error)
862 goto cleanup_dquot;
863 }
864 mb_cache_entry_release(ce);
865 ce = NULL;
866 } else if (bs->bh && s->base == bs->bh->b_data) {
867 /* We were modifying this block in-place. */
868 ea_bdebug(bs->bh, "keeping this block");
869 new_bh = bs->bh;
870 get_bh(new_bh);
871 } else {
872 /* We need to allocate a new block */
873 ext4_fsblk_t goal, block;
874
875 goal = ext4_group_first_block_no(sb,
876 EXT4_I(inode)->i_block_group);
877
878 /* non-extent files can't have physical blocks past 2^32 */
879 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
880 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
881
882 /*
883 * take i_data_sem because we will test
884 * i_delalloc_reserved_flag in ext4_mb_new_blocks
885 */
886 down_read((&EXT4_I(inode)->i_data_sem));
887 block = ext4_new_meta_blocks(handle, inode, goal, 0,
888 NULL, &error);
889 up_read((&EXT4_I(inode)->i_data_sem));
890 if (error)
891 goto cleanup;
892
893 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
894 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
895
896 ea_idebug(inode, "creating block %llu",
897 (unsigned long long)block);
898
899 new_bh = sb_getblk(sb, block);
900 if (!new_bh) {
901getblk_failed:
902 ext4_free_blocks(handle, inode, NULL, block, 1,
903 EXT4_FREE_BLOCKS_METADATA);
904 error = -EIO;
905 goto cleanup;
906 }
907 lock_buffer(new_bh);
908 error = ext4_journal_get_create_access(handle, new_bh);
909 if (error) {
910 unlock_buffer(new_bh);
911 goto getblk_failed;
912 }
913 memcpy(new_bh->b_data, s->base, new_bh->b_size);
914 set_buffer_uptodate(new_bh);
915 unlock_buffer(new_bh);
916 ext4_xattr_cache_insert(new_bh);
917 error = ext4_handle_dirty_xattr_block(handle,
918 inode, new_bh);
919 if (error)
920 goto cleanup;
921 }
922 }
923
924 /* Update the inode. */
925 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
926
927 /* Drop the previous xattr block. */
928 if (bs->bh && bs->bh != new_bh)
929 ext4_xattr_release_block(handle, inode, bs->bh);
930 error = 0;
931
932cleanup:
933 if (ce)
934 mb_cache_entry_release(ce);
935 brelse(new_bh);
936 if (!(bs->bh && s->base == bs->bh->b_data))
937 kfree(s->base);
938
939 return error;
940
941cleanup_dquot:
942 dquot_free_block(inode, 1);
943 goto cleanup;
944
945bad_block:
946 EXT4_ERROR_INODE(inode, "bad block %llu",
947 EXT4_I(inode)->i_file_acl);
948 goto cleanup;
949
950#undef header
951}
952
953struct ext4_xattr_ibody_find {
954 struct ext4_xattr_search s;
955 struct ext4_iloc iloc;
956};
957
958static int
959ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
960 struct ext4_xattr_ibody_find *is)
961{
962 struct ext4_xattr_ibody_header *header;
963 struct ext4_inode *raw_inode;
964 int error;
965
966 if (EXT4_I(inode)->i_extra_isize == 0)
967 return 0;
968 raw_inode = ext4_raw_inode(&is->iloc);
969 header = IHDR(inode, raw_inode);
970 is->s.base = is->s.first = IFIRST(header);
971 is->s.here = is->s.first;
972 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
973 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
974 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
975 if (error)
976 return error;
977 /* Find the named attribute. */
978 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
979 i->name, is->s.end -
980 (void *)is->s.base, 0);
981 if (error && error != -ENODATA)
982 return error;
983 is->s.not_found = error;
984 }
985 return 0;
986}
987
988static int
989ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
990 struct ext4_xattr_info *i,
991 struct ext4_xattr_ibody_find *is)
992{
993 struct ext4_xattr_ibody_header *header;
994 struct ext4_xattr_search *s = &is->s;
995 int error;
996
997 if (EXT4_I(inode)->i_extra_isize == 0)
998 return -ENOSPC;
999 error = ext4_xattr_set_entry(i, s);
1000 if (error)
1001 return error;
1002 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1003 if (!IS_LAST_ENTRY(s->first)) {
1004 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1005 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1006 } else {
1007 header->h_magic = cpu_to_le32(0);
1008 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1009 }
1010 return 0;
1011}
1012
1013/*
1014 * ext4_xattr_set_handle()
1015 *
1016 * Create, replace or remove an extended attribute for this inode. Value
1017 * is NULL to remove an existing extended attribute, and non-NULL to
1018 * either replace an existing extended attribute, or create a new extended
1019 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1020 * specify that an extended attribute must exist and must not exist
1021 * previous to the call, respectively.
1022 *
1023 * Returns 0, or a negative error number on failure.
1024 */
1025int
1026ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1027 const char *name, const void *value, size_t value_len,
1028 int flags)
1029{
1030 struct ext4_xattr_info i = {
1031 .name_index = name_index,
1032 .name = name,
1033 .value = value,
1034 .value_len = value_len,
1035
1036 };
1037 struct ext4_xattr_ibody_find is = {
1038 .s = { .not_found = -ENODATA, },
1039 };
1040 struct ext4_xattr_block_find bs = {
1041 .s = { .not_found = -ENODATA, },
1042 };
1043 unsigned long no_expand;
1044 int error;
1045
1046 if (!name)
1047 return -EINVAL;
1048 if (strlen(name) > 255)
1049 return -ERANGE;
1050 down_write(&EXT4_I(inode)->xattr_sem);
1051 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1052 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1053
1054 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1055 if (error)
1056 goto cleanup;
1057
1058 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1059 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1060 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1061 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1062 }
1063
1064 error = ext4_xattr_ibody_find(inode, &i, &is);
1065 if (error)
1066 goto cleanup;
1067 if (is.s.not_found)
1068 error = ext4_xattr_block_find(inode, &i, &bs);
1069 if (error)
1070 goto cleanup;
1071 if (is.s.not_found && bs.s.not_found) {
1072 error = -ENODATA;
1073 if (flags & XATTR_REPLACE)
1074 goto cleanup;
1075 error = 0;
1076 if (!value)
1077 goto cleanup;
1078 } else {
1079 error = -EEXIST;
1080 if (flags & XATTR_CREATE)
1081 goto cleanup;
1082 }
1083 if (!value) {
1084 if (!is.s.not_found)
1085 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1086 else if (!bs.s.not_found)
1087 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1088 } else {
1089 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1090 if (!error && !bs.s.not_found) {
1091 i.value = NULL;
1092 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1093 } else if (error == -ENOSPC) {
1094 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1095 error = ext4_xattr_block_find(inode, &i, &bs);
1096 if (error)
1097 goto cleanup;
1098 }
1099 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1100 if (error)
1101 goto cleanup;
1102 if (!is.s.not_found) {
1103 i.value = NULL;
1104 error = ext4_xattr_ibody_set(handle, inode, &i,
1105 &is);
1106 }
1107 }
1108 }
1109 if (!error) {
1110 ext4_xattr_update_super_block(handle, inode->i_sb);
1111 inode->i_ctime = ext4_current_time(inode);
1112 if (!value)
1113 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1114 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1115 /*
1116 * The bh is consumed by ext4_mark_iloc_dirty, even with
1117 * error != 0.
1118 */
1119 is.iloc.bh = NULL;
1120 if (IS_SYNC(inode))
1121 ext4_handle_sync(handle);
1122 }
1123
1124cleanup:
1125 brelse(is.iloc.bh);
1126 brelse(bs.bh);
1127 if (no_expand == 0)
1128 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1129 up_write(&EXT4_I(inode)->xattr_sem);
1130 return error;
1131}
1132
1133/*
1134 * ext4_xattr_set()
1135 *
1136 * Like ext4_xattr_set_handle, but start from an inode. This extended
1137 * attribute modification is a filesystem transaction by itself.
1138 *
1139 * Returns 0, or a negative error number on failure.
1140 */
1141int
1142ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1143 const void *value, size_t value_len, int flags)
1144{
1145 handle_t *handle;
1146 int error, retries = 0;
1147
1148retry:
1149 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1150 if (IS_ERR(handle)) {
1151 error = PTR_ERR(handle);
1152 } else {
1153 int error2;
1154
1155 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1156 value, value_len, flags);
1157 error2 = ext4_journal_stop(handle);
1158 if (error == -ENOSPC &&
1159 ext4_should_retry_alloc(inode->i_sb, &retries))
1160 goto retry;
1161 if (error == 0)
1162 error = error2;
1163 }
1164
1165 return error;
1166}
1167
1168/*
1169 * Shift the EA entries in the inode to create space for the increased
1170 * i_extra_isize.
1171 */
1172static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1173 int value_offs_shift, void *to,
1174 void *from, size_t n, int blocksize)
1175{
1176 struct ext4_xattr_entry *last = entry;
1177 int new_offs;
1178
1179 /* Adjust the value offsets of the entries */
1180 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1181 if (!last->e_value_block && last->e_value_size) {
1182 new_offs = le16_to_cpu(last->e_value_offs) +
1183 value_offs_shift;
1184 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1185 > blocksize);
1186 last->e_value_offs = cpu_to_le16(new_offs);
1187 }
1188 }
1189 /* Shift the entries by n bytes */
1190 memmove(to, from, n);
1191}
1192
1193/*
1194 * Expand an inode by new_extra_isize bytes when EAs are present.
1195 * Returns 0 on success or negative error number on failure.
1196 */
1197int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1198 struct ext4_inode *raw_inode, handle_t *handle)
1199{
1200 struct ext4_xattr_ibody_header *header;
1201 struct ext4_xattr_entry *entry, *last, *first;
1202 struct buffer_head *bh = NULL;
1203 struct ext4_xattr_ibody_find *is = NULL;
1204 struct ext4_xattr_block_find *bs = NULL;
1205 char *buffer = NULL, *b_entry_name = NULL;
1206 size_t min_offs, free;
1207 int total_ino, total_blk;
1208 void *base, *start, *end;
1209 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1210 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1211
1212 down_write(&EXT4_I(inode)->xattr_sem);
1213retry:
1214 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1215 up_write(&EXT4_I(inode)->xattr_sem);
1216 return 0;
1217 }
1218
1219 header = IHDR(inode, raw_inode);
1220 entry = IFIRST(header);
1221
1222 /*
1223 * Check if enough free space is available in the inode to shift the
1224 * entries ahead by new_extra_isize.
1225 */
1226
1227 base = start = entry;
1228 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1229 min_offs = end - base;
1230 last = entry;
1231 total_ino = sizeof(struct ext4_xattr_ibody_header);
1232
1233 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1234 if (free >= new_extra_isize) {
1235 entry = IFIRST(header);
1236 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1237 - new_extra_isize, (void *)raw_inode +
1238 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1239 (void *)header, total_ino,
1240 inode->i_sb->s_blocksize);
1241 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1242 error = 0;
1243 goto cleanup;
1244 }
1245
1246 /*
1247 * Enough free space isn't available in the inode, check if
1248 * EA block can hold new_extra_isize bytes.
1249 */
1250 if (EXT4_I(inode)->i_file_acl) {
1251 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1252 error = -EIO;
1253 if (!bh)
1254 goto cleanup;
1255 if (ext4_xattr_check_block(inode, bh)) {
1256 EXT4_ERROR_INODE(inode, "bad block %llu",
1257 EXT4_I(inode)->i_file_acl);
1258 error = -EIO;
1259 goto cleanup;
1260 }
1261 base = BHDR(bh);
1262 first = BFIRST(bh);
1263 end = bh->b_data + bh->b_size;
1264 min_offs = end - base;
1265 free = ext4_xattr_free_space(first, &min_offs, base,
1266 &total_blk);
1267 if (free < new_extra_isize) {
1268 if (!tried_min_extra_isize && s_min_extra_isize) {
1269 tried_min_extra_isize++;
1270 new_extra_isize = s_min_extra_isize;
1271 brelse(bh);
1272 goto retry;
1273 }
1274 error = -1;
1275 goto cleanup;
1276 }
1277 } else {
1278 free = inode->i_sb->s_blocksize;
1279 }
1280
1281 while (new_extra_isize > 0) {
1282 size_t offs, size, entry_size;
1283 struct ext4_xattr_entry *small_entry = NULL;
1284 struct ext4_xattr_info i = {
1285 .value = NULL,
1286 .value_len = 0,
1287 };
1288 unsigned int total_size; /* EA entry size + value size */
1289 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1290 unsigned int min_total_size = ~0U;
1291
1292 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1293 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1294 if (!is || !bs) {
1295 error = -ENOMEM;
1296 goto cleanup;
1297 }
1298
1299 is->s.not_found = -ENODATA;
1300 bs->s.not_found = -ENODATA;
1301 is->iloc.bh = NULL;
1302 bs->bh = NULL;
1303
1304 last = IFIRST(header);
1305 /* Find the entry best suited to be pushed into EA block */
1306 entry = NULL;
1307 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1308 total_size =
1309 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1310 EXT4_XATTR_LEN(last->e_name_len);
1311 if (total_size <= free && total_size < min_total_size) {
1312 if (total_size < new_extra_isize) {
1313 small_entry = last;
1314 } else {
1315 entry = last;
1316 min_total_size = total_size;
1317 }
1318 }
1319 }
1320
1321 if (entry == NULL) {
1322 if (small_entry) {
1323 entry = small_entry;
1324 } else {
1325 if (!tried_min_extra_isize &&
1326 s_min_extra_isize) {
1327 tried_min_extra_isize++;
1328 new_extra_isize = s_min_extra_isize;
1329 goto retry;
1330 }
1331 error = -1;
1332 goto cleanup;
1333 }
1334 }
1335 offs = le16_to_cpu(entry->e_value_offs);
1336 size = le32_to_cpu(entry->e_value_size);
1337 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1338 i.name_index = entry->e_name_index,
1339 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1340 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1341 if (!buffer || !b_entry_name) {
1342 error = -ENOMEM;
1343 goto cleanup;
1344 }
1345 /* Save the entry name and the entry value */
1346 memcpy(buffer, (void *)IFIRST(header) + offs,
1347 EXT4_XATTR_SIZE(size));
1348 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1349 b_entry_name[entry->e_name_len] = '\0';
1350 i.name = b_entry_name;
1351
1352 error = ext4_get_inode_loc(inode, &is->iloc);
1353 if (error)
1354 goto cleanup;
1355
1356 error = ext4_xattr_ibody_find(inode, &i, is);
1357 if (error)
1358 goto cleanup;
1359
1360 /* Remove the chosen entry from the inode */
1361 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1362 if (error)
1363 goto cleanup;
1364
1365 entry = IFIRST(header);
1366 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1367 shift_bytes = new_extra_isize;
1368 else
1369 shift_bytes = entry_size + size;
1370 /* Adjust the offsets and shift the remaining entries ahead */
1371 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1372 shift_bytes, (void *)raw_inode +
1373 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1374 (void *)header, total_ino - entry_size,
1375 inode->i_sb->s_blocksize);
1376
1377 extra_isize += shift_bytes;
1378 new_extra_isize -= shift_bytes;
1379 EXT4_I(inode)->i_extra_isize = extra_isize;
1380
1381 i.name = b_entry_name;
1382 i.value = buffer;
1383 i.value_len = size;
1384 error = ext4_xattr_block_find(inode, &i, bs);
1385 if (error)
1386 goto cleanup;
1387
1388 /* Add entry which was removed from the inode into the block */
1389 error = ext4_xattr_block_set(handle, inode, &i, bs);
1390 if (error)
1391 goto cleanup;
1392 kfree(b_entry_name);
1393 kfree(buffer);
1394 b_entry_name = NULL;
1395 buffer = NULL;
1396 brelse(is->iloc.bh);
1397 kfree(is);
1398 kfree(bs);
1399 }
1400 brelse(bh);
1401 up_write(&EXT4_I(inode)->xattr_sem);
1402 return 0;
1403
1404cleanup:
1405 kfree(b_entry_name);
1406 kfree(buffer);
1407 if (is)
1408 brelse(is->iloc.bh);
1409 kfree(is);
1410 kfree(bs);
1411 brelse(bh);
1412 up_write(&EXT4_I(inode)->xattr_sem);
1413 return error;
1414}
1415
1416
1417
1418/*
1419 * ext4_xattr_delete_inode()
1420 *
1421 * Free extended attribute resources associated with this inode. This
1422 * is called immediately before an inode is freed. We have exclusive
1423 * access to the inode.
1424 */
1425void
1426ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1427{
1428 struct buffer_head *bh = NULL;
1429
1430 if (!EXT4_I(inode)->i_file_acl)
1431 goto cleanup;
1432 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1433 if (!bh) {
1434 EXT4_ERROR_INODE(inode, "block %llu read error",
1435 EXT4_I(inode)->i_file_acl);
1436 goto cleanup;
1437 }
1438 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1439 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1440 EXT4_ERROR_INODE(inode, "bad block %llu",
1441 EXT4_I(inode)->i_file_acl);
1442 goto cleanup;
1443 }
1444 ext4_xattr_release_block(handle, inode, bh);
1445 EXT4_I(inode)->i_file_acl = 0;
1446
1447cleanup:
1448 brelse(bh);
1449}
1450
1451/*
1452 * ext4_xattr_put_super()
1453 *
1454 * This is called when a file system is unmounted.
1455 */
1456void
1457ext4_xattr_put_super(struct super_block *sb)
1458{
1459 mb_cache_shrink(sb->s_bdev);
1460}
1461
1462/*
1463 * ext4_xattr_cache_insert()
1464 *
1465 * Create a new entry in the extended attribute cache, and insert
1466 * it unless such an entry is already in the cache.
1467 *
1468 * Returns 0, or a negative error number on failure.
1469 */
1470static void
1471ext4_xattr_cache_insert(struct buffer_head *bh)
1472{
1473 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1474 struct mb_cache_entry *ce;
1475 int error;
1476
1477 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1478 if (!ce) {
1479 ea_bdebug(bh, "out of memory");
1480 return;
1481 }
1482 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1483 if (error) {
1484 mb_cache_entry_free(ce);
1485 if (error == -EBUSY) {
1486 ea_bdebug(bh, "already in cache");
1487 error = 0;
1488 }
1489 } else {
1490 ea_bdebug(bh, "inserting [%x]", (int)hash);
1491 mb_cache_entry_release(ce);
1492 }
1493}
1494
1495/*
1496 * ext4_xattr_cmp()
1497 *
1498 * Compare two extended attribute blocks for equality.
1499 *
1500 * Returns 0 if the blocks are equal, 1 if they differ, and
1501 * a negative error number on errors.
1502 */
1503static int
1504ext4_xattr_cmp(struct ext4_xattr_header *header1,
1505 struct ext4_xattr_header *header2)
1506{
1507 struct ext4_xattr_entry *entry1, *entry2;
1508
1509 entry1 = ENTRY(header1+1);
1510 entry2 = ENTRY(header2+1);
1511 while (!IS_LAST_ENTRY(entry1)) {
1512 if (IS_LAST_ENTRY(entry2))
1513 return 1;
1514 if (entry1->e_hash != entry2->e_hash ||
1515 entry1->e_name_index != entry2->e_name_index ||
1516 entry1->e_name_len != entry2->e_name_len ||
1517 entry1->e_value_size != entry2->e_value_size ||
1518 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1519 return 1;
1520 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1521 return -EIO;
1522 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1523 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1524 le32_to_cpu(entry1->e_value_size)))
1525 return 1;
1526
1527 entry1 = EXT4_XATTR_NEXT(entry1);
1528 entry2 = EXT4_XATTR_NEXT(entry2);
1529 }
1530 if (!IS_LAST_ENTRY(entry2))
1531 return 1;
1532 return 0;
1533}
1534
1535/*
1536 * ext4_xattr_cache_find()
1537 *
1538 * Find an identical extended attribute block.
1539 *
1540 * Returns a pointer to the block found, or NULL if such a block was
1541 * not found or an error occurred.
1542 */
1543static struct buffer_head *
1544ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1545 struct mb_cache_entry **pce)
1546{
1547 __u32 hash = le32_to_cpu(header->h_hash);
1548 struct mb_cache_entry *ce;
1549
1550 if (!header->h_hash)
1551 return NULL; /* never share */
1552 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1553again:
1554 ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1555 hash);
1556 while (ce) {
1557 struct buffer_head *bh;
1558
1559 if (IS_ERR(ce)) {
1560 if (PTR_ERR(ce) == -EAGAIN)
1561 goto again;
1562 break;
1563 }
1564 bh = sb_bread(inode->i_sb, ce->e_block);
1565 if (!bh) {
1566 EXT4_ERROR_INODE(inode, "block %lu read error",
1567 (unsigned long) ce->e_block);
1568 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1569 EXT4_XATTR_REFCOUNT_MAX) {
1570 ea_idebug(inode, "block %lu refcount %d>=%d",
1571 (unsigned long) ce->e_block,
1572 le32_to_cpu(BHDR(bh)->h_refcount),
1573 EXT4_XATTR_REFCOUNT_MAX);
1574 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1575 *pce = ce;
1576 return bh;
1577 }
1578 brelse(bh);
1579 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1580 }
1581 return NULL;
1582}
1583
1584#define NAME_HASH_SHIFT 5
1585#define VALUE_HASH_SHIFT 16
1586
1587/*
1588 * ext4_xattr_hash_entry()
1589 *
1590 * Compute the hash of an extended attribute.
1591 */
1592static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1593 struct ext4_xattr_entry *entry)
1594{
1595 __u32 hash = 0;
1596 char *name = entry->e_name;
1597 int n;
1598
1599 for (n = 0; n < entry->e_name_len; n++) {
1600 hash = (hash << NAME_HASH_SHIFT) ^
1601 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1602 *name++;
1603 }
1604
1605 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1606 __le32 *value = (__le32 *)((char *)header +
1607 le16_to_cpu(entry->e_value_offs));
1608 for (n = (le32_to_cpu(entry->e_value_size) +
1609 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1610 hash = (hash << VALUE_HASH_SHIFT) ^
1611 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1612 le32_to_cpu(*value++);
1613 }
1614 }
1615 entry->e_hash = cpu_to_le32(hash);
1616}
1617
1618#undef NAME_HASH_SHIFT
1619#undef VALUE_HASH_SHIFT
1620
1621#define BLOCK_HASH_SHIFT 16
1622
1623/*
1624 * ext4_xattr_rehash()
1625 *
1626 * Re-compute the extended attribute hash value after an entry has changed.
1627 */
1628static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1629 struct ext4_xattr_entry *entry)
1630{
1631 struct ext4_xattr_entry *here;
1632 __u32 hash = 0;
1633
1634 ext4_xattr_hash_entry(header, entry);
1635 here = ENTRY(header+1);
1636 while (!IS_LAST_ENTRY(here)) {
1637 if (!here->e_hash) {
1638 /* Block is not shared if an entry's hash value == 0 */
1639 hash = 0;
1640 break;
1641 }
1642 hash = (hash << BLOCK_HASH_SHIFT) ^
1643 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1644 le32_to_cpu(here->e_hash);
1645 here = EXT4_XATTR_NEXT(here);
1646 }
1647 header->h_hash = cpu_to_le32(hash);
1648}
1649
1650#undef BLOCK_HASH_SHIFT
1651
1652int __init
1653ext4_init_xattr(void)
1654{
1655 ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1656 if (!ext4_xattr_cache)
1657 return -ENOMEM;
1658 return 0;
1659}
1660
1661void
1662ext4_exit_xattr(void)
1663{
1664 if (ext4_xattr_cache)
1665 mb_cache_destroy(ext4_xattr_cache);
1666 ext4_xattr_cache = NULL;
1667}
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
75static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
76static struct buffer_head *ext4_xattr_cache_find(struct inode *,
77 struct ext4_xattr_header *,
78 struct mb_cache_entry **);
79static void ext4_xattr_rehash(struct ext4_xattr_header *,
80 struct ext4_xattr_entry *);
81static int ext4_xattr_list(struct dentry *dentry, char *buffer,
82 size_t buffer_size);
83
84static 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
96const 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
112static __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
133static int ext4_xattr_block_csum_verify(struct inode *inode,
134 struct buffer_head *bh)
135{
136 struct ext4_xattr_header *hdr = BHDR(bh);
137 int ret = 1;
138
139 if (ext4_has_metadata_csum(inode->i_sb)) {
140 lock_buffer(bh);
141 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
142 bh->b_blocknr, hdr));
143 unlock_buffer(bh);
144 }
145 return ret;
146}
147
148static void ext4_xattr_block_csum_set(struct inode *inode,
149 struct buffer_head *bh)
150{
151 if (ext4_has_metadata_csum(inode->i_sb))
152 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
153 bh->b_blocknr, BHDR(bh));
154}
155
156static inline const struct xattr_handler *
157ext4_xattr_handler(int name_index)
158{
159 const struct xattr_handler *handler = NULL;
160
161 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
162 handler = ext4_xattr_handler_map[name_index];
163 return handler;
164}
165
166/*
167 * Inode operation listxattr()
168 *
169 * d_inode(dentry)->i_mutex: don't care
170 */
171ssize_t
172ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
173{
174 return ext4_xattr_list(dentry, buffer, size);
175}
176
177static int
178ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
179 void *value_start)
180{
181 struct ext4_xattr_entry *e = entry;
182
183 /* Find the end of the names list */
184 while (!IS_LAST_ENTRY(e)) {
185 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
186 if ((void *)next >= end)
187 return -EFSCORRUPTED;
188 e = next;
189 }
190
191 /* Check the values */
192 while (!IS_LAST_ENTRY(entry)) {
193 if (entry->e_value_block != 0)
194 return -EFSCORRUPTED;
195 if (entry->e_value_size != 0) {
196 u16 offs = le16_to_cpu(entry->e_value_offs);
197 u32 size = le32_to_cpu(entry->e_value_size);
198 void *value;
199
200 /*
201 * The value cannot overlap the names, and the value
202 * with padding cannot extend beyond 'end'. Check both
203 * the padded and unpadded sizes, since the size may
204 * overflow to 0 when adding padding.
205 */
206 if (offs > end - value_start)
207 return -EFSCORRUPTED;
208 value = value_start + offs;
209 if (value < (void *)e + sizeof(u32) ||
210 size > end - value ||
211 EXT4_XATTR_SIZE(size) > end - value)
212 return -EFSCORRUPTED;
213 }
214 entry = EXT4_XATTR_NEXT(entry);
215 }
216
217 return 0;
218}
219
220static inline int
221ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
222{
223 int error;
224
225 if (buffer_verified(bh))
226 return 0;
227
228 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
229 BHDR(bh)->h_blocks != cpu_to_le32(1))
230 return -EFSCORRUPTED;
231 if (!ext4_xattr_block_csum_verify(inode, bh))
232 return -EFSBADCRC;
233 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
234 bh->b_data);
235 if (!error)
236 set_buffer_verified(bh);
237 return error;
238}
239
240static int
241__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
242 void *end, const char *function, unsigned int line)
243{
244 int error = -EFSCORRUPTED;
245
246 if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
247 (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
248 goto errout;
249 error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header));
250errout:
251 if (error)
252 __ext4_error_inode(inode, function, line, 0,
253 "corrupted in-inode xattr");
254 return error;
255}
256
257#define xattr_check_inode(inode, header, end) \
258 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
259
260static inline int
261ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
262{
263 size_t value_size = le32_to_cpu(entry->e_value_size);
264
265 if (entry->e_value_block != 0 || value_size > size ||
266 le16_to_cpu(entry->e_value_offs) + value_size > size)
267 return -EFSCORRUPTED;
268 return 0;
269}
270
271static int
272ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
273 const char *name, size_t size, int sorted)
274{
275 struct ext4_xattr_entry *entry;
276 size_t name_len;
277 int cmp = 1;
278
279 if (name == NULL)
280 return -EINVAL;
281 name_len = strlen(name);
282 entry = *pentry;
283 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
284 cmp = name_index - entry->e_name_index;
285 if (!cmp)
286 cmp = name_len - entry->e_name_len;
287 if (!cmp)
288 cmp = memcmp(name, entry->e_name, name_len);
289 if (cmp <= 0 && (sorted || cmp == 0))
290 break;
291 }
292 *pentry = entry;
293 if (!cmp && ext4_xattr_check_entry(entry, size))
294 return -EFSCORRUPTED;
295 return cmp ? -ENODATA : 0;
296}
297
298static int
299ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
300 void *buffer, size_t buffer_size)
301{
302 struct buffer_head *bh = NULL;
303 struct ext4_xattr_entry *entry;
304 size_t size;
305 int error;
306 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
307
308 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
309 name_index, name, buffer, (long)buffer_size);
310
311 error = -ENODATA;
312 if (!EXT4_I(inode)->i_file_acl)
313 goto cleanup;
314 ea_idebug(inode, "reading block %llu",
315 (unsigned long long)EXT4_I(inode)->i_file_acl);
316 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
317 if (!bh)
318 goto cleanup;
319 ea_bdebug(bh, "b_count=%d, refcount=%d",
320 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
321 if (ext4_xattr_check_block(inode, bh)) {
322bad_block:
323 EXT4_ERROR_INODE(inode, "bad block %llu",
324 EXT4_I(inode)->i_file_acl);
325 error = -EFSCORRUPTED;
326 goto cleanup;
327 }
328 ext4_xattr_cache_insert(ext4_mb_cache, bh);
329 entry = BFIRST(bh);
330 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
331 if (error == -EFSCORRUPTED)
332 goto bad_block;
333 if (error)
334 goto cleanup;
335 size = le32_to_cpu(entry->e_value_size);
336 if (buffer) {
337 error = -ERANGE;
338 if (size > buffer_size)
339 goto cleanup;
340 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
341 size);
342 }
343 error = size;
344
345cleanup:
346 brelse(bh);
347 return error;
348}
349
350int
351ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
352 void *buffer, size_t buffer_size)
353{
354 struct ext4_xattr_ibody_header *header;
355 struct ext4_xattr_entry *entry;
356 struct ext4_inode *raw_inode;
357 struct ext4_iloc iloc;
358 size_t size;
359 void *end;
360 int error;
361
362 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
363 return -ENODATA;
364 error = ext4_get_inode_loc(inode, &iloc);
365 if (error)
366 return error;
367 raw_inode = ext4_raw_inode(&iloc);
368 header = IHDR(inode, raw_inode);
369 entry = IFIRST(header);
370 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
371 error = xattr_check_inode(inode, header, end);
372 if (error)
373 goto cleanup;
374 error = ext4_xattr_find_entry(&entry, name_index, name,
375 end - (void *)entry, 0);
376 if (error)
377 goto cleanup;
378 size = le32_to_cpu(entry->e_value_size);
379 if (buffer) {
380 error = -ERANGE;
381 if (size > buffer_size)
382 goto cleanup;
383 memcpy(buffer, (void *)IFIRST(header) +
384 le16_to_cpu(entry->e_value_offs), size);
385 }
386 error = size;
387
388cleanup:
389 brelse(iloc.bh);
390 return error;
391}
392
393/*
394 * ext4_xattr_get()
395 *
396 * Copy an extended attribute into the buffer
397 * provided, or compute the buffer size required.
398 * Buffer is NULL to compute the size of the buffer required.
399 *
400 * Returns a negative error number on failure, or the number of bytes
401 * used / required on success.
402 */
403int
404ext4_xattr_get(struct inode *inode, int name_index, const char *name,
405 void *buffer, size_t buffer_size)
406{
407 int error;
408
409 if (strlen(name) > 255)
410 return -ERANGE;
411
412 down_read(&EXT4_I(inode)->xattr_sem);
413 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
414 buffer_size);
415 if (error == -ENODATA)
416 error = ext4_xattr_block_get(inode, name_index, name, buffer,
417 buffer_size);
418 up_read(&EXT4_I(inode)->xattr_sem);
419 return error;
420}
421
422static int
423ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
424 char *buffer, size_t buffer_size)
425{
426 size_t rest = buffer_size;
427
428 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
429 const struct xattr_handler *handler =
430 ext4_xattr_handler(entry->e_name_index);
431
432 if (handler && (!handler->list || handler->list(dentry))) {
433 const char *prefix = handler->prefix ?: handler->name;
434 size_t prefix_len = strlen(prefix);
435 size_t size = prefix_len + entry->e_name_len + 1;
436
437 if (buffer) {
438 if (size > rest)
439 return -ERANGE;
440 memcpy(buffer, prefix, prefix_len);
441 buffer += prefix_len;
442 memcpy(buffer, entry->e_name, entry->e_name_len);
443 buffer += entry->e_name_len;
444 *buffer++ = 0;
445 }
446 rest -= size;
447 }
448 }
449 return buffer_size - rest; /* total size */
450}
451
452static int
453ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
454{
455 struct inode *inode = d_inode(dentry);
456 struct buffer_head *bh = NULL;
457 int error;
458 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
459
460 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
461 buffer, (long)buffer_size);
462
463 error = 0;
464 if (!EXT4_I(inode)->i_file_acl)
465 goto cleanup;
466 ea_idebug(inode, "reading block %llu",
467 (unsigned long long)EXT4_I(inode)->i_file_acl);
468 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
469 error = -EIO;
470 if (!bh)
471 goto cleanup;
472 ea_bdebug(bh, "b_count=%d, refcount=%d",
473 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
474 if (ext4_xattr_check_block(inode, bh)) {
475 EXT4_ERROR_INODE(inode, "bad block %llu",
476 EXT4_I(inode)->i_file_acl);
477 error = -EFSCORRUPTED;
478 goto cleanup;
479 }
480 ext4_xattr_cache_insert(ext4_mb_cache, bh);
481 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
482
483cleanup:
484 brelse(bh);
485
486 return error;
487}
488
489static int
490ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
491{
492 struct inode *inode = d_inode(dentry);
493 struct ext4_xattr_ibody_header *header;
494 struct ext4_inode *raw_inode;
495 struct ext4_iloc iloc;
496 void *end;
497 int error;
498
499 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
500 return 0;
501 error = ext4_get_inode_loc(inode, &iloc);
502 if (error)
503 return error;
504 raw_inode = ext4_raw_inode(&iloc);
505 header = IHDR(inode, raw_inode);
506 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
507 error = xattr_check_inode(inode, header, end);
508 if (error)
509 goto cleanup;
510 error = ext4_xattr_list_entries(dentry, IFIRST(header),
511 buffer, buffer_size);
512
513cleanup:
514 brelse(iloc.bh);
515 return error;
516}
517
518/*
519 * ext4_xattr_list()
520 *
521 * Copy a list of attribute names into the buffer
522 * provided, or compute the buffer size required.
523 * Buffer is NULL to compute the size of the buffer required.
524 *
525 * Returns a negative error number on failure, or the number of bytes
526 * used / required on success.
527 */
528static int
529ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
530{
531 int ret, ret2;
532
533 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
534 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
535 if (ret < 0)
536 goto errout;
537 if (buffer) {
538 buffer += ret;
539 buffer_size -= ret;
540 }
541 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
542 if (ret < 0)
543 goto errout;
544 ret += ret2;
545errout:
546 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
547 return ret;
548}
549
550/*
551 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
552 * not set, set it.
553 */
554static void ext4_xattr_update_super_block(handle_t *handle,
555 struct super_block *sb)
556{
557 if (ext4_has_feature_xattr(sb))
558 return;
559
560 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
561 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
562 ext4_set_feature_xattr(sb);
563 ext4_handle_dirty_super(handle, sb);
564 }
565}
566
567/*
568 * Release the xattr block BH: If the reference count is > 1, decrement it;
569 * otherwise free the block.
570 */
571static void
572ext4_xattr_release_block(handle_t *handle, struct inode *inode,
573 struct buffer_head *bh)
574{
575 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
576 u32 hash, ref;
577 int error = 0;
578
579 BUFFER_TRACE(bh, "get_write_access");
580 error = ext4_journal_get_write_access(handle, bh);
581 if (error)
582 goto out;
583
584 lock_buffer(bh);
585 hash = le32_to_cpu(BHDR(bh)->h_hash);
586 ref = le32_to_cpu(BHDR(bh)->h_refcount);
587 if (ref == 1) {
588 ea_bdebug(bh, "refcount now=0; freeing");
589 /*
590 * This must happen under buffer lock for
591 * ext4_xattr_block_set() to reliably detect freed block
592 */
593 mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
594 get_bh(bh);
595 unlock_buffer(bh);
596 ext4_free_blocks(handle, inode, bh, 0, 1,
597 EXT4_FREE_BLOCKS_METADATA |
598 EXT4_FREE_BLOCKS_FORGET);
599 } else {
600 ref--;
601 BHDR(bh)->h_refcount = cpu_to_le32(ref);
602 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
603 struct mb_cache_entry *ce;
604
605 ce = mb_cache_entry_get(ext4_mb_cache, hash,
606 bh->b_blocknr);
607 if (ce) {
608 ce->e_reusable = 1;
609 mb_cache_entry_put(ext4_mb_cache, ce);
610 }
611 }
612
613 ext4_xattr_block_csum_set(inode, bh);
614 /*
615 * Beware of this ugliness: Releasing of xattr block references
616 * from different inodes can race and so we have to protect
617 * from a race where someone else frees the block (and releases
618 * its journal_head) before we are done dirtying the buffer. In
619 * nojournal mode this race is harmless and we actually cannot
620 * call ext4_handle_dirty_metadata() with locked buffer as
621 * that function can call sync_dirty_buffer() so for that case
622 * we handle the dirtying after unlocking the buffer.
623 */
624 if (ext4_handle_valid(handle))
625 error = ext4_handle_dirty_metadata(handle, inode, bh);
626 unlock_buffer(bh);
627 if (!ext4_handle_valid(handle))
628 error = ext4_handle_dirty_metadata(handle, inode, bh);
629 if (IS_SYNC(inode))
630 ext4_handle_sync(handle);
631 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
632 ea_bdebug(bh, "refcount now=%d; releasing",
633 le32_to_cpu(BHDR(bh)->h_refcount));
634 }
635out:
636 ext4_std_error(inode->i_sb, error);
637 return;
638}
639
640/*
641 * Find the available free space for EAs. This also returns the total number of
642 * bytes used by EA entries.
643 */
644static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
645 size_t *min_offs, void *base, int *total)
646{
647 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
648 if (last->e_value_size) {
649 size_t offs = le16_to_cpu(last->e_value_offs);
650 if (offs < *min_offs)
651 *min_offs = offs;
652 }
653 if (total)
654 *total += EXT4_XATTR_LEN(last->e_name_len);
655 }
656 return (*min_offs - ((void *)last - base) - sizeof(__u32));
657}
658
659static int
660ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
661{
662 struct ext4_xattr_entry *last;
663 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
664
665 /* Compute min_offs and last. */
666 last = s->first;
667 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
668 if (last->e_value_size) {
669 size_t offs = le16_to_cpu(last->e_value_offs);
670 if (offs < min_offs)
671 min_offs = offs;
672 }
673 }
674 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
675 if (!s->not_found) {
676 if (s->here->e_value_size) {
677 size_t size = le32_to_cpu(s->here->e_value_size);
678 free += EXT4_XATTR_SIZE(size);
679 }
680 free += EXT4_XATTR_LEN(name_len);
681 }
682 if (i->value) {
683 if (free < EXT4_XATTR_LEN(name_len) +
684 EXT4_XATTR_SIZE(i->value_len))
685 return -ENOSPC;
686 }
687
688 if (i->value && s->not_found) {
689 /* Insert the new name. */
690 size_t size = EXT4_XATTR_LEN(name_len);
691 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
692 memmove((void *)s->here + size, s->here, rest);
693 memset(s->here, 0, size);
694 s->here->e_name_index = i->name_index;
695 s->here->e_name_len = name_len;
696 memcpy(s->here->e_name, i->name, name_len);
697 } else {
698 if (s->here->e_value_size) {
699 void *first_val = s->base + min_offs;
700 size_t offs = le16_to_cpu(s->here->e_value_offs);
701 void *val = s->base + offs;
702 size_t size = EXT4_XATTR_SIZE(
703 le32_to_cpu(s->here->e_value_size));
704
705 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
706 /* The old and the new value have the same
707 size. Just replace. */
708 s->here->e_value_size =
709 cpu_to_le32(i->value_len);
710 if (i->value == EXT4_ZERO_XATTR_VALUE) {
711 memset(val, 0, size);
712 } else {
713 /* Clear pad bytes first. */
714 memset(val + size - EXT4_XATTR_PAD, 0,
715 EXT4_XATTR_PAD);
716 memcpy(val, i->value, i->value_len);
717 }
718 return 0;
719 }
720
721 /* Remove the old value. */
722 memmove(first_val + size, first_val, val - first_val);
723 memset(first_val, 0, size);
724 s->here->e_value_size = 0;
725 s->here->e_value_offs = 0;
726 min_offs += size;
727
728 /* Adjust all value offsets. */
729 last = s->first;
730 while (!IS_LAST_ENTRY(last)) {
731 size_t o = le16_to_cpu(last->e_value_offs);
732 if (last->e_value_size && o < offs)
733 last->e_value_offs =
734 cpu_to_le16(o + size);
735 last = EXT4_XATTR_NEXT(last);
736 }
737 }
738 if (!i->value) {
739 /* Remove the old name. */
740 size_t size = EXT4_XATTR_LEN(name_len);
741 last = ENTRY((void *)last - size);
742 memmove(s->here, (void *)s->here + size,
743 (void *)last - (void *)s->here + sizeof(__u32));
744 memset(last, 0, size);
745 }
746 }
747
748 if (i->value) {
749 /* Insert the new value. */
750 s->here->e_value_size = cpu_to_le32(i->value_len);
751 if (i->value_len) {
752 size_t size = EXT4_XATTR_SIZE(i->value_len);
753 void *val = s->base + min_offs - size;
754 s->here->e_value_offs = cpu_to_le16(min_offs - size);
755 if (i->value == EXT4_ZERO_XATTR_VALUE) {
756 memset(val, 0, size);
757 } else {
758 /* Clear the pad bytes first. */
759 memset(val + size - EXT4_XATTR_PAD, 0,
760 EXT4_XATTR_PAD);
761 memcpy(val, i->value, i->value_len);
762 }
763 }
764 }
765 return 0;
766}
767
768struct ext4_xattr_block_find {
769 struct ext4_xattr_search s;
770 struct buffer_head *bh;
771};
772
773static int
774ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
775 struct ext4_xattr_block_find *bs)
776{
777 struct super_block *sb = inode->i_sb;
778 int error;
779
780 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
781 i->name_index, i->name, i->value, (long)i->value_len);
782
783 if (EXT4_I(inode)->i_file_acl) {
784 /* The inode already has an extended attribute block. */
785 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
786 error = -EIO;
787 if (!bs->bh)
788 goto cleanup;
789 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
790 atomic_read(&(bs->bh->b_count)),
791 le32_to_cpu(BHDR(bs->bh)->h_refcount));
792 if (ext4_xattr_check_block(inode, bs->bh)) {
793 EXT4_ERROR_INODE(inode, "bad block %llu",
794 EXT4_I(inode)->i_file_acl);
795 error = -EFSCORRUPTED;
796 goto cleanup;
797 }
798 /* Find the named attribute. */
799 bs->s.base = BHDR(bs->bh);
800 bs->s.first = BFIRST(bs->bh);
801 bs->s.end = bs->bh->b_data + bs->bh->b_size;
802 bs->s.here = bs->s.first;
803 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
804 i->name, bs->bh->b_size, 1);
805 if (error && error != -ENODATA)
806 goto cleanup;
807 bs->s.not_found = error;
808 }
809 error = 0;
810
811cleanup:
812 return error;
813}
814
815static int
816ext4_xattr_block_set(handle_t *handle, struct inode *inode,
817 struct ext4_xattr_info *i,
818 struct ext4_xattr_block_find *bs)
819{
820 struct super_block *sb = inode->i_sb;
821 struct buffer_head *new_bh = NULL;
822 struct ext4_xattr_search *s = &bs->s;
823 struct mb_cache_entry *ce = NULL;
824 int error = 0;
825 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
826
827#define header(x) ((struct ext4_xattr_header *)(x))
828
829 if (i->value && i->value_len > sb->s_blocksize)
830 return -ENOSPC;
831 if (s->base) {
832 BUFFER_TRACE(bs->bh, "get_write_access");
833 error = ext4_journal_get_write_access(handle, bs->bh);
834 if (error)
835 goto cleanup;
836 lock_buffer(bs->bh);
837
838 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
839 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
840
841 /*
842 * This must happen under buffer lock for
843 * ext4_xattr_block_set() to reliably detect modified
844 * block
845 */
846 mb_cache_entry_delete_block(ext4_mb_cache, hash,
847 bs->bh->b_blocknr);
848 ea_bdebug(bs->bh, "modifying in-place");
849 error = ext4_xattr_set_entry(i, s);
850 if (!error) {
851 if (!IS_LAST_ENTRY(s->first))
852 ext4_xattr_rehash(header(s->base),
853 s->here);
854 ext4_xattr_cache_insert(ext4_mb_cache,
855 bs->bh);
856 }
857 ext4_xattr_block_csum_set(inode, bs->bh);
858 unlock_buffer(bs->bh);
859 if (error == -EFSCORRUPTED)
860 goto bad_block;
861 if (!error)
862 error = ext4_handle_dirty_metadata(handle,
863 inode,
864 bs->bh);
865 if (error)
866 goto cleanup;
867 goto inserted;
868 } else {
869 int offset = (char *)s->here - bs->bh->b_data;
870
871 unlock_buffer(bs->bh);
872 ea_bdebug(bs->bh, "cloning");
873 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
874 error = -ENOMEM;
875 if (s->base == NULL)
876 goto cleanup;
877 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
878 s->first = ENTRY(header(s->base)+1);
879 header(s->base)->h_refcount = cpu_to_le32(1);
880 s->here = ENTRY(s->base + offset);
881 s->end = s->base + bs->bh->b_size;
882 }
883 } else {
884 /* Allocate a buffer where we construct the new block. */
885 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
886 /* assert(header == s->base) */
887 error = -ENOMEM;
888 if (s->base == NULL)
889 goto cleanup;
890 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
891 header(s->base)->h_blocks = cpu_to_le32(1);
892 header(s->base)->h_refcount = cpu_to_le32(1);
893 s->first = ENTRY(header(s->base)+1);
894 s->here = ENTRY(header(s->base)+1);
895 s->end = s->base + sb->s_blocksize;
896 }
897
898 error = ext4_xattr_set_entry(i, s);
899 if (error == -EFSCORRUPTED)
900 goto bad_block;
901 if (error)
902 goto cleanup;
903 if (!IS_LAST_ENTRY(s->first))
904 ext4_xattr_rehash(header(s->base), s->here);
905
906inserted:
907 if (!IS_LAST_ENTRY(s->first)) {
908 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
909 if (new_bh) {
910 /* We found an identical block in the cache. */
911 if (new_bh == bs->bh)
912 ea_bdebug(new_bh, "keeping");
913 else {
914 u32 ref;
915
916 /* The old block is released after updating
917 the inode. */
918 error = dquot_alloc_block(inode,
919 EXT4_C2B(EXT4_SB(sb), 1));
920 if (error)
921 goto cleanup;
922 BUFFER_TRACE(new_bh, "get_write_access");
923 error = ext4_journal_get_write_access(handle,
924 new_bh);
925 if (error)
926 goto cleanup_dquot;
927 lock_buffer(new_bh);
928 /*
929 * We have to be careful about races with
930 * freeing, rehashing or adding references to
931 * xattr block. Once we hold buffer lock xattr
932 * block's state is stable so we can check
933 * whether the block got freed / rehashed or
934 * not. Since we unhash mbcache entry under
935 * buffer lock when freeing / rehashing xattr
936 * block, checking whether entry is still
937 * hashed is reliable. Same rules hold for
938 * e_reusable handling.
939 */
940 if (hlist_bl_unhashed(&ce->e_hash_list) ||
941 !ce->e_reusable) {
942 /*
943 * Undo everything and check mbcache
944 * again.
945 */
946 unlock_buffer(new_bh);
947 dquot_free_block(inode,
948 EXT4_C2B(EXT4_SB(sb),
949 1));
950 brelse(new_bh);
951 mb_cache_entry_put(ext4_mb_cache, ce);
952 ce = NULL;
953 new_bh = NULL;
954 goto inserted;
955 }
956 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
957 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
958 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
959 ce->e_reusable = 0;
960 ea_bdebug(new_bh, "reusing; refcount now=%d",
961 ref);
962 ext4_xattr_block_csum_set(inode, new_bh);
963 unlock_buffer(new_bh);
964 error = ext4_handle_dirty_metadata(handle,
965 inode,
966 new_bh);
967 if (error)
968 goto cleanup_dquot;
969 }
970 mb_cache_entry_touch(ext4_mb_cache, ce);
971 mb_cache_entry_put(ext4_mb_cache, ce);
972 ce = NULL;
973 } else if (bs->bh && s->base == bs->bh->b_data) {
974 /* We were modifying this block in-place. */
975 ea_bdebug(bs->bh, "keeping this block");
976 new_bh = bs->bh;
977 get_bh(new_bh);
978 } else {
979 /* We need to allocate a new block */
980 ext4_fsblk_t goal, block;
981
982 goal = ext4_group_first_block_no(sb,
983 EXT4_I(inode)->i_block_group);
984
985 /* non-extent files can't have physical blocks past 2^32 */
986 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
987 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
988
989 block = ext4_new_meta_blocks(handle, inode, goal, 0,
990 NULL, &error);
991 if (error)
992 goto cleanup;
993
994 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
995 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
996
997 ea_idebug(inode, "creating block %llu",
998 (unsigned long long)block);
999
1000 new_bh = sb_getblk(sb, block);
1001 if (unlikely(!new_bh)) {
1002 error = -ENOMEM;
1003getblk_failed:
1004 ext4_free_blocks(handle, inode, NULL, block, 1,
1005 EXT4_FREE_BLOCKS_METADATA);
1006 goto cleanup;
1007 }
1008 lock_buffer(new_bh);
1009 error = ext4_journal_get_create_access(handle, new_bh);
1010 if (error) {
1011 unlock_buffer(new_bh);
1012 error = -EIO;
1013 goto getblk_failed;
1014 }
1015 memcpy(new_bh->b_data, s->base, new_bh->b_size);
1016 ext4_xattr_block_csum_set(inode, new_bh);
1017 set_buffer_uptodate(new_bh);
1018 unlock_buffer(new_bh);
1019 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1020 error = ext4_handle_dirty_metadata(handle, inode,
1021 new_bh);
1022 if (error)
1023 goto cleanup;
1024 }
1025 }
1026
1027 /* Update the inode. */
1028 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1029
1030 /* Drop the previous xattr block. */
1031 if (bs->bh && bs->bh != new_bh)
1032 ext4_xattr_release_block(handle, inode, bs->bh);
1033 error = 0;
1034
1035cleanup:
1036 if (ce)
1037 mb_cache_entry_put(ext4_mb_cache, ce);
1038 brelse(new_bh);
1039 if (!(bs->bh && s->base == bs->bh->b_data))
1040 kfree(s->base);
1041
1042 return error;
1043
1044cleanup_dquot:
1045 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1046 goto cleanup;
1047
1048bad_block:
1049 EXT4_ERROR_INODE(inode, "bad block %llu",
1050 EXT4_I(inode)->i_file_acl);
1051 goto cleanup;
1052
1053#undef header
1054}
1055
1056int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
1057 struct ext4_xattr_ibody_find *is)
1058{
1059 struct ext4_xattr_ibody_header *header;
1060 struct ext4_inode *raw_inode;
1061 int error;
1062
1063 if (EXT4_I(inode)->i_extra_isize == 0)
1064 return 0;
1065 raw_inode = ext4_raw_inode(&is->iloc);
1066 header = IHDR(inode, raw_inode);
1067 is->s.base = is->s.first = IFIRST(header);
1068 is->s.here = is->s.first;
1069 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1070 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1071 error = xattr_check_inode(inode, header, is->s.end);
1072 if (error)
1073 return error;
1074 /* Find the named attribute. */
1075 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1076 i->name, is->s.end -
1077 (void *)is->s.base, 0);
1078 if (error && error != -ENODATA)
1079 return error;
1080 is->s.not_found = error;
1081 }
1082 return 0;
1083}
1084
1085int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1086 struct ext4_xattr_info *i,
1087 struct ext4_xattr_ibody_find *is)
1088{
1089 struct ext4_xattr_ibody_header *header;
1090 struct ext4_xattr_search *s = &is->s;
1091 int error;
1092
1093 if (EXT4_I(inode)->i_extra_isize == 0)
1094 return -ENOSPC;
1095 error = ext4_xattr_set_entry(i, s);
1096 if (error) {
1097 if (error == -ENOSPC &&
1098 ext4_has_inline_data(inode)) {
1099 error = ext4_try_to_evict_inline_data(handle, inode,
1100 EXT4_XATTR_LEN(strlen(i->name) +
1101 EXT4_XATTR_SIZE(i->value_len)));
1102 if (error)
1103 return error;
1104 error = ext4_xattr_ibody_find(inode, i, is);
1105 if (error)
1106 return error;
1107 error = ext4_xattr_set_entry(i, s);
1108 }
1109 if (error)
1110 return error;
1111 }
1112 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1113 if (!IS_LAST_ENTRY(s->first)) {
1114 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1115 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1116 } else {
1117 header->h_magic = cpu_to_le32(0);
1118 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1119 }
1120 return 0;
1121}
1122
1123static int ext4_xattr_ibody_set(struct inode *inode,
1124 struct ext4_xattr_info *i,
1125 struct ext4_xattr_ibody_find *is)
1126{
1127 struct ext4_xattr_ibody_header *header;
1128 struct ext4_xattr_search *s = &is->s;
1129 int error;
1130
1131 if (EXT4_I(inode)->i_extra_isize == 0)
1132 return -ENOSPC;
1133 error = ext4_xattr_set_entry(i, s);
1134 if (error)
1135 return error;
1136 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1137 if (!IS_LAST_ENTRY(s->first)) {
1138 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1139 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1140 } else {
1141 header->h_magic = cpu_to_le32(0);
1142 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1143 }
1144 return 0;
1145}
1146
1147static int ext4_xattr_value_same(struct ext4_xattr_search *s,
1148 struct ext4_xattr_info *i)
1149{
1150 void *value;
1151
1152 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
1153 return 0;
1154 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
1155 return !memcmp(value, i->value, i->value_len);
1156}
1157
1158/*
1159 * ext4_xattr_set_handle()
1160 *
1161 * Create, replace or remove an extended attribute for this inode. Value
1162 * is NULL to remove an existing extended attribute, and non-NULL to
1163 * either replace an existing extended attribute, or create a new extended
1164 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1165 * specify that an extended attribute must exist and must not exist
1166 * previous to the call, respectively.
1167 *
1168 * Returns 0, or a negative error number on failure.
1169 */
1170int
1171ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1172 const char *name, const void *value, size_t value_len,
1173 int flags)
1174{
1175 struct ext4_xattr_info i = {
1176 .name_index = name_index,
1177 .name = name,
1178 .value = value,
1179 .value_len = value_len,
1180
1181 };
1182 struct ext4_xattr_ibody_find is = {
1183 .s = { .not_found = -ENODATA, },
1184 };
1185 struct ext4_xattr_block_find bs = {
1186 .s = { .not_found = -ENODATA, },
1187 };
1188 int no_expand;
1189 int error;
1190
1191 if (!name)
1192 return -EINVAL;
1193 if (strlen(name) > 255)
1194 return -ERANGE;
1195 ext4_write_lock_xattr(inode, &no_expand);
1196
1197 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1198 if (error)
1199 goto cleanup;
1200
1201 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1202 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1203 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1204 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1205 }
1206
1207 error = ext4_xattr_ibody_find(inode, &i, &is);
1208 if (error)
1209 goto cleanup;
1210 if (is.s.not_found)
1211 error = ext4_xattr_block_find(inode, &i, &bs);
1212 if (error)
1213 goto cleanup;
1214 if (is.s.not_found && bs.s.not_found) {
1215 error = -ENODATA;
1216 if (flags & XATTR_REPLACE)
1217 goto cleanup;
1218 error = 0;
1219 if (!value)
1220 goto cleanup;
1221 } else {
1222 error = -EEXIST;
1223 if (flags & XATTR_CREATE)
1224 goto cleanup;
1225 }
1226 if (!value) {
1227 if (!is.s.not_found)
1228 error = ext4_xattr_ibody_set(inode, &i, &is);
1229 else if (!bs.s.not_found)
1230 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1231 } else {
1232 error = 0;
1233 /* Xattr value did not change? Save us some work and bail out */
1234 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
1235 goto cleanup;
1236 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
1237 goto cleanup;
1238
1239 error = ext4_xattr_ibody_set(inode, &i, &is);
1240 if (!error && !bs.s.not_found) {
1241 i.value = NULL;
1242 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1243 } else if (error == -ENOSPC) {
1244 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1245 error = ext4_xattr_block_find(inode, &i, &bs);
1246 if (error)
1247 goto cleanup;
1248 }
1249 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1250 if (error)
1251 goto cleanup;
1252 if (!is.s.not_found) {
1253 i.value = NULL;
1254 error = ext4_xattr_ibody_set(inode, &i, &is);
1255 }
1256 }
1257 }
1258 if (!error) {
1259 ext4_xattr_update_super_block(handle, inode->i_sb);
1260 inode->i_ctime = current_time(inode);
1261 if (!value)
1262 no_expand = 0;
1263 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1264 /*
1265 * The bh is consumed by ext4_mark_iloc_dirty, even with
1266 * error != 0.
1267 */
1268 is.iloc.bh = NULL;
1269 if (IS_SYNC(inode))
1270 ext4_handle_sync(handle);
1271 }
1272
1273cleanup:
1274 brelse(is.iloc.bh);
1275 brelse(bs.bh);
1276 ext4_write_unlock_xattr(inode, &no_expand);
1277 return error;
1278}
1279
1280/*
1281 * ext4_xattr_set()
1282 *
1283 * Like ext4_xattr_set_handle, but start from an inode. This extended
1284 * attribute modification is a filesystem transaction by itself.
1285 *
1286 * Returns 0, or a negative error number on failure.
1287 */
1288int
1289ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1290 const void *value, size_t value_len, int flags)
1291{
1292 handle_t *handle;
1293 int error, retries = 0;
1294 int credits = ext4_jbd2_credits_xattr(inode);
1295
1296retry:
1297 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1298 if (IS_ERR(handle)) {
1299 error = PTR_ERR(handle);
1300 } else {
1301 int error2;
1302
1303 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1304 value, value_len, flags);
1305 error2 = ext4_journal_stop(handle);
1306 if (error == -ENOSPC &&
1307 ext4_should_retry_alloc(inode->i_sb, &retries))
1308 goto retry;
1309 if (error == 0)
1310 error = error2;
1311 }
1312
1313 return error;
1314}
1315
1316/*
1317 * Shift the EA entries in the inode to create space for the increased
1318 * i_extra_isize.
1319 */
1320static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1321 int value_offs_shift, void *to,
1322 void *from, size_t n)
1323{
1324 struct ext4_xattr_entry *last = entry;
1325 int new_offs;
1326
1327 /* We always shift xattr headers further thus offsets get lower */
1328 BUG_ON(value_offs_shift > 0);
1329
1330 /* Adjust the value offsets of the entries */
1331 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1332 if (last->e_value_size) {
1333 new_offs = le16_to_cpu(last->e_value_offs) +
1334 value_offs_shift;
1335 last->e_value_offs = cpu_to_le16(new_offs);
1336 }
1337 }
1338 /* Shift the entries by n bytes */
1339 memmove(to, from, n);
1340}
1341
1342/*
1343 * Move xattr pointed to by 'entry' from inode into external xattr block
1344 */
1345static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
1346 struct ext4_inode *raw_inode,
1347 struct ext4_xattr_entry *entry)
1348{
1349 struct ext4_xattr_ibody_find *is = NULL;
1350 struct ext4_xattr_block_find *bs = NULL;
1351 char *buffer = NULL, *b_entry_name = NULL;
1352 size_t value_offs, value_size;
1353 struct ext4_xattr_info i = {
1354 .value = NULL,
1355 .value_len = 0,
1356 .name_index = entry->e_name_index,
1357 };
1358 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1359 int error;
1360
1361 value_offs = le16_to_cpu(entry->e_value_offs);
1362 value_size = le32_to_cpu(entry->e_value_size);
1363
1364 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1365 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1366 buffer = kmalloc(value_size, GFP_NOFS);
1367 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1368 if (!is || !bs || !buffer || !b_entry_name) {
1369 error = -ENOMEM;
1370 goto out;
1371 }
1372
1373 is->s.not_found = -ENODATA;
1374 bs->s.not_found = -ENODATA;
1375 is->iloc.bh = NULL;
1376 bs->bh = NULL;
1377
1378 /* Save the entry name and the entry value */
1379 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
1380 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1381 b_entry_name[entry->e_name_len] = '\0';
1382 i.name = b_entry_name;
1383
1384 error = ext4_get_inode_loc(inode, &is->iloc);
1385 if (error)
1386 goto out;
1387
1388 error = ext4_xattr_ibody_find(inode, &i, is);
1389 if (error)
1390 goto out;
1391
1392 /* Remove the chosen entry from the inode */
1393 error = ext4_xattr_ibody_set(inode, &i, is);
1394 if (error)
1395 goto out;
1396
1397 i.name = b_entry_name;
1398 i.value = buffer;
1399 i.value_len = value_size;
1400 error = ext4_xattr_block_find(inode, &i, bs);
1401 if (error)
1402 goto out;
1403
1404 /* Add entry which was removed from the inode into the block */
1405 error = ext4_xattr_block_set(handle, inode, &i, bs);
1406 if (error)
1407 goto out;
1408 error = 0;
1409out:
1410 kfree(b_entry_name);
1411 kfree(buffer);
1412 if (is)
1413 brelse(is->iloc.bh);
1414 kfree(is);
1415 kfree(bs);
1416
1417 return error;
1418}
1419
1420static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
1421 struct ext4_inode *raw_inode,
1422 int isize_diff, size_t ifree,
1423 size_t bfree, int *total_ino)
1424{
1425 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
1426 struct ext4_xattr_entry *small_entry;
1427 struct ext4_xattr_entry *entry;
1428 struct ext4_xattr_entry *last;
1429 unsigned int entry_size; /* EA entry size */
1430 unsigned int total_size; /* EA entry size + value size */
1431 unsigned int min_total_size;
1432 int error;
1433
1434 while (isize_diff > ifree) {
1435 entry = NULL;
1436 small_entry = NULL;
1437 min_total_size = ~0U;
1438 last = IFIRST(header);
1439 /* Find the entry best suited to be pushed into EA block */
1440 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1441 total_size =
1442 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1443 EXT4_XATTR_LEN(last->e_name_len);
1444 if (total_size <= bfree &&
1445 total_size < min_total_size) {
1446 if (total_size + ifree < isize_diff) {
1447 small_entry = last;
1448 } else {
1449 entry = last;
1450 min_total_size = total_size;
1451 }
1452 }
1453 }
1454
1455 if (entry == NULL) {
1456 if (small_entry == NULL)
1457 return -ENOSPC;
1458 entry = small_entry;
1459 }
1460
1461 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1462 total_size = entry_size +
1463 EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
1464 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
1465 entry);
1466 if (error)
1467 return error;
1468
1469 *total_ino -= entry_size;
1470 ifree += total_size;
1471 bfree -= total_size;
1472 }
1473
1474 return 0;
1475}
1476
1477/*
1478 * Expand an inode by new_extra_isize bytes when EAs are present.
1479 * Returns 0 on success or negative error number on failure.
1480 */
1481int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1482 struct ext4_inode *raw_inode, handle_t *handle)
1483{
1484 struct ext4_xattr_ibody_header *header;
1485 struct buffer_head *bh = NULL;
1486 size_t min_offs;
1487 size_t ifree, bfree;
1488 int total_ino;
1489 void *base, *end;
1490 int error = 0, tried_min_extra_isize = 0;
1491 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1492 int isize_diff; /* How much do we need to grow i_extra_isize */
1493 int no_expand;
1494
1495 if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
1496 return 0;
1497
1498retry:
1499 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
1500 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
1501 goto out;
1502
1503 header = IHDR(inode, raw_inode);
1504
1505 /*
1506 * Check if enough free space is available in the inode to shift the
1507 * entries ahead by new_extra_isize.
1508 */
1509
1510 base = IFIRST(header);
1511 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1512 min_offs = end - base;
1513 total_ino = sizeof(struct ext4_xattr_ibody_header);
1514
1515 error = xattr_check_inode(inode, header, end);
1516 if (error)
1517 goto cleanup;
1518
1519 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
1520 if (ifree >= isize_diff)
1521 goto shift;
1522
1523 /*
1524 * Enough free space isn't available in the inode, check if
1525 * EA block can hold new_extra_isize bytes.
1526 */
1527 if (EXT4_I(inode)->i_file_acl) {
1528 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1529 error = -EIO;
1530 if (!bh)
1531 goto cleanup;
1532 if (ext4_xattr_check_block(inode, bh)) {
1533 EXT4_ERROR_INODE(inode, "bad block %llu",
1534 EXT4_I(inode)->i_file_acl);
1535 error = -EFSCORRUPTED;
1536 goto cleanup;
1537 }
1538 base = BHDR(bh);
1539 end = bh->b_data + bh->b_size;
1540 min_offs = end - base;
1541 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
1542 NULL);
1543 if (bfree + ifree < isize_diff) {
1544 if (!tried_min_extra_isize && s_min_extra_isize) {
1545 tried_min_extra_isize++;
1546 new_extra_isize = s_min_extra_isize;
1547 brelse(bh);
1548 goto retry;
1549 }
1550 error = -ENOSPC;
1551 goto cleanup;
1552 }
1553 } else {
1554 bfree = inode->i_sb->s_blocksize;
1555 }
1556
1557 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
1558 isize_diff, ifree, bfree,
1559 &total_ino);
1560 if (error) {
1561 if (error == -ENOSPC && !tried_min_extra_isize &&
1562 s_min_extra_isize) {
1563 tried_min_extra_isize++;
1564 new_extra_isize = s_min_extra_isize;
1565 brelse(bh);
1566 goto retry;
1567 }
1568 goto cleanup;
1569 }
1570shift:
1571 /* Adjust the offsets and shift the remaining entries ahead */
1572 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
1573 - new_extra_isize, (void *)raw_inode +
1574 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1575 (void *)header, total_ino);
1576 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1577 brelse(bh);
1578out:
1579 ext4_write_unlock_xattr(inode, &no_expand);
1580 return 0;
1581
1582cleanup:
1583 brelse(bh);
1584 /*
1585 * Inode size expansion failed; don't try again
1586 */
1587 no_expand = 1;
1588 ext4_write_unlock_xattr(inode, &no_expand);
1589 return error;
1590}
1591
1592
1593
1594/*
1595 * ext4_xattr_delete_inode()
1596 *
1597 * Free extended attribute resources associated with this inode. This
1598 * is called immediately before an inode is freed. We have exclusive
1599 * access to the inode.
1600 */
1601void
1602ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1603{
1604 struct buffer_head *bh = NULL;
1605
1606 if (!EXT4_I(inode)->i_file_acl)
1607 goto cleanup;
1608 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1609 if (!bh) {
1610 EXT4_ERROR_INODE(inode, "block %llu read error",
1611 EXT4_I(inode)->i_file_acl);
1612 goto cleanup;
1613 }
1614 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1615 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1616 EXT4_ERROR_INODE(inode, "bad block %llu",
1617 EXT4_I(inode)->i_file_acl);
1618 goto cleanup;
1619 }
1620 ext4_xattr_release_block(handle, inode, bh);
1621 EXT4_I(inode)->i_file_acl = 0;
1622
1623cleanup:
1624 brelse(bh);
1625}
1626
1627/*
1628 * ext4_xattr_cache_insert()
1629 *
1630 * Create a new entry in the extended attribute cache, and insert
1631 * it unless such an entry is already in the cache.
1632 *
1633 * Returns 0, or a negative error number on failure.
1634 */
1635static void
1636ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1637{
1638 struct ext4_xattr_header *header = BHDR(bh);
1639 __u32 hash = le32_to_cpu(header->h_hash);
1640 int reusable = le32_to_cpu(header->h_refcount) <
1641 EXT4_XATTR_REFCOUNT_MAX;
1642 int error;
1643
1644 error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1645 bh->b_blocknr, reusable);
1646 if (error) {
1647 if (error == -EBUSY)
1648 ea_bdebug(bh, "already in cache");
1649 } else
1650 ea_bdebug(bh, "inserting [%x]", (int)hash);
1651}
1652
1653/*
1654 * ext4_xattr_cmp()
1655 *
1656 * Compare two extended attribute blocks for equality.
1657 *
1658 * Returns 0 if the blocks are equal, 1 if they differ, and
1659 * a negative error number on errors.
1660 */
1661static int
1662ext4_xattr_cmp(struct ext4_xattr_header *header1,
1663 struct ext4_xattr_header *header2)
1664{
1665 struct ext4_xattr_entry *entry1, *entry2;
1666
1667 entry1 = ENTRY(header1+1);
1668 entry2 = ENTRY(header2+1);
1669 while (!IS_LAST_ENTRY(entry1)) {
1670 if (IS_LAST_ENTRY(entry2))
1671 return 1;
1672 if (entry1->e_hash != entry2->e_hash ||
1673 entry1->e_name_index != entry2->e_name_index ||
1674 entry1->e_name_len != entry2->e_name_len ||
1675 entry1->e_value_size != entry2->e_value_size ||
1676 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1677 return 1;
1678 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1679 return -EFSCORRUPTED;
1680 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1681 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1682 le32_to_cpu(entry1->e_value_size)))
1683 return 1;
1684
1685 entry1 = EXT4_XATTR_NEXT(entry1);
1686 entry2 = EXT4_XATTR_NEXT(entry2);
1687 }
1688 if (!IS_LAST_ENTRY(entry2))
1689 return 1;
1690 return 0;
1691}
1692
1693/*
1694 * ext4_xattr_cache_find()
1695 *
1696 * Find an identical extended attribute block.
1697 *
1698 * Returns a pointer to the block found, or NULL if such a block was
1699 * not found or an error occurred.
1700 */
1701static struct buffer_head *
1702ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1703 struct mb_cache_entry **pce)
1704{
1705 __u32 hash = le32_to_cpu(header->h_hash);
1706 struct mb_cache_entry *ce;
1707 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1708
1709 if (!header->h_hash)
1710 return NULL; /* never share */
1711 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1712 ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1713 while (ce) {
1714 struct buffer_head *bh;
1715
1716 bh = sb_bread(inode->i_sb, ce->e_block);
1717 if (!bh) {
1718 EXT4_ERROR_INODE(inode, "block %lu read error",
1719 (unsigned long) ce->e_block);
1720 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1721 *pce = ce;
1722 return bh;
1723 }
1724 brelse(bh);
1725 ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1726 }
1727 return NULL;
1728}
1729
1730#define NAME_HASH_SHIFT 5
1731#define VALUE_HASH_SHIFT 16
1732
1733/*
1734 * ext4_xattr_hash_entry()
1735 *
1736 * Compute the hash of an extended attribute.
1737 */
1738static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1739 struct ext4_xattr_entry *entry)
1740{
1741 __u32 hash = 0;
1742 char *name = entry->e_name;
1743 int n;
1744
1745 for (n = 0; n < entry->e_name_len; n++) {
1746 hash = (hash << NAME_HASH_SHIFT) ^
1747 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1748 *name++;
1749 }
1750
1751 if (entry->e_value_size != 0) {
1752 __le32 *value = (__le32 *)((char *)header +
1753 le16_to_cpu(entry->e_value_offs));
1754 for (n = (le32_to_cpu(entry->e_value_size) +
1755 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1756 hash = (hash << VALUE_HASH_SHIFT) ^
1757 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1758 le32_to_cpu(*value++);
1759 }
1760 }
1761 entry->e_hash = cpu_to_le32(hash);
1762}
1763
1764#undef NAME_HASH_SHIFT
1765#undef VALUE_HASH_SHIFT
1766
1767#define BLOCK_HASH_SHIFT 16
1768
1769/*
1770 * ext4_xattr_rehash()
1771 *
1772 * Re-compute the extended attribute hash value after an entry has changed.
1773 */
1774static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1775 struct ext4_xattr_entry *entry)
1776{
1777 struct ext4_xattr_entry *here;
1778 __u32 hash = 0;
1779
1780 ext4_xattr_hash_entry(header, entry);
1781 here = ENTRY(header+1);
1782 while (!IS_LAST_ENTRY(here)) {
1783 if (!here->e_hash) {
1784 /* Block is not shared if an entry's hash value == 0 */
1785 hash = 0;
1786 break;
1787 }
1788 hash = (hash << BLOCK_HASH_SHIFT) ^
1789 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1790 le32_to_cpu(here->e_hash);
1791 here = EXT4_XATTR_NEXT(here);
1792 }
1793 header->h_hash = cpu_to_le32(hash);
1794}
1795
1796#undef BLOCK_HASH_SHIFT
1797
1798#define HASH_BUCKET_BITS 10
1799
1800struct mb_cache *
1801ext4_xattr_create_cache(void)
1802{
1803 return mb_cache_create(HASH_BUCKET_BITS);
1804}
1805
1806void ext4_xattr_destroy_cache(struct mb_cache *cache)
1807{
1808 if (cache)
1809 mb_cache_destroy(cache);
1810}
1811