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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/xattr.c
4 *
5 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
6 *
7 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
8 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
9 * Extended attributes for symlinks and special files added per
10 * suggestion of Luka Renko <luka.renko@hermes.si>.
11 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
12 * Red Hat Inc.
13 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
14 * and Andreas Gruenbacher <agruen@suse.de>.
15 */
16
17/*
18 * Extended attributes are stored directly in inodes (on file systems with
19 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
20 * field contains the block number if an inode uses an additional block. All
21 * attributes must fit in the inode and one additional block. Blocks that
22 * contain the identical set of attributes may be shared among several inodes.
23 * Identical blocks are detected by keeping a cache of blocks that have
24 * recently been accessed.
25 *
26 * The attributes in inodes and on blocks have a different header; the entries
27 * are stored in the same format:
28 *
29 * +------------------+
30 * | header |
31 * | entry 1 | |
32 * | entry 2 | | growing downwards
33 * | entry 3 | v
34 * | four null bytes |
35 * | . . . |
36 * | value 1 | ^
37 * | value 3 | | growing upwards
38 * | value 2 | |
39 * +------------------+
40 *
41 * The header is followed by multiple entry descriptors. In disk blocks, the
42 * entry descriptors are kept sorted. In inodes, they are unsorted. The
43 * attribute values are aligned to the end of the block in no specific order.
44 *
45 * Locking strategy
46 * ----------------
47 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
48 * EA blocks are only changed if they are exclusive to an inode, so
49 * holding xattr_sem also means that nothing but the EA block's reference
50 * count can change. Multiple writers to the same block are synchronized
51 * by the buffer lock.
52 */
53
54#include <linux/init.h>
55#include <linux/fs.h>
56#include <linux/slab.h>
57#include <linux/mbcache.h>
58#include <linux/quotaops.h>
59#include <linux/iversion.h>
60#include "ext4_jbd2.h"
61#include "ext4.h"
62#include "xattr.h"
63#include "acl.h"
64
65#ifdef EXT4_XATTR_DEBUG
66# define ea_idebug(inode, fmt, ...) \
67 printk(KERN_DEBUG "inode %s:%lu: " fmt "\n", \
68 inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
69# define ea_bdebug(bh, fmt, ...) \
70 printk(KERN_DEBUG "block %pg:%lu: " fmt "\n", \
71 bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
72#else
73# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
74# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
75#endif
76
77static void ext4_xattr_block_cache_insert(struct mb_cache *,
78 struct buffer_head *);
79static struct buffer_head *
80ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
81 struct mb_cache_entry **);
82static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
83 size_t value_count);
84static void ext4_xattr_rehash(struct ext4_xattr_header *);
85
86static const struct xattr_handler * const ext4_xattr_handler_map[] = {
87 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
88#ifdef CONFIG_EXT4_FS_POSIX_ACL
89 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
90 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
91#endif
92 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
93#ifdef CONFIG_EXT4_FS_SECURITY
94 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
95#endif
96};
97
98const struct xattr_handler *ext4_xattr_handlers[] = {
99 &ext4_xattr_user_handler,
100 &ext4_xattr_trusted_handler,
101#ifdef CONFIG_EXT4_FS_POSIX_ACL
102 &posix_acl_access_xattr_handler,
103 &posix_acl_default_xattr_handler,
104#endif
105#ifdef CONFIG_EXT4_FS_SECURITY
106 &ext4_xattr_security_handler,
107#endif
108 NULL
109};
110
111#define EA_BLOCK_CACHE(inode) (((struct ext4_sb_info *) \
112 inode->i_sb->s_fs_info)->s_ea_block_cache)
113
114#define EA_INODE_CACHE(inode) (((struct ext4_sb_info *) \
115 inode->i_sb->s_fs_info)->s_ea_inode_cache)
116
117static int
118ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
119 struct inode *inode);
120
121#ifdef CONFIG_LOCKDEP
122void ext4_xattr_inode_set_class(struct inode *ea_inode)
123{
124 lockdep_set_subclass(&ea_inode->i_rwsem, 1);
125}
126#endif
127
128static __le32 ext4_xattr_block_csum(struct inode *inode,
129 sector_t block_nr,
130 struct ext4_xattr_header *hdr)
131{
132 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
133 __u32 csum;
134 __le64 dsk_block_nr = cpu_to_le64(block_nr);
135 __u32 dummy_csum = 0;
136 int offset = offsetof(struct ext4_xattr_header, h_checksum);
137
138 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
139 sizeof(dsk_block_nr));
140 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
141 csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
142 offset += sizeof(dummy_csum);
143 csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
144 EXT4_BLOCK_SIZE(inode->i_sb) - offset);
145
146 return cpu_to_le32(csum);
147}
148
149static int ext4_xattr_block_csum_verify(struct inode *inode,
150 struct buffer_head *bh)
151{
152 struct ext4_xattr_header *hdr = BHDR(bh);
153 int ret = 1;
154
155 if (ext4_has_metadata_csum(inode->i_sb)) {
156 lock_buffer(bh);
157 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
158 bh->b_blocknr, hdr));
159 unlock_buffer(bh);
160 }
161 return ret;
162}
163
164static void ext4_xattr_block_csum_set(struct inode *inode,
165 struct buffer_head *bh)
166{
167 if (ext4_has_metadata_csum(inode->i_sb))
168 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
169 bh->b_blocknr, BHDR(bh));
170}
171
172static inline const struct xattr_handler *
173ext4_xattr_handler(int name_index)
174{
175 const struct xattr_handler *handler = NULL;
176
177 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
178 handler = ext4_xattr_handler_map[name_index];
179 return handler;
180}
181
182static int
183ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
184 void *value_start)
185{
186 struct ext4_xattr_entry *e = entry;
187
188 /* Find the end of the names list */
189 while (!IS_LAST_ENTRY(e)) {
190 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
191 if ((void *)next >= end)
192 return -EFSCORRUPTED;
193 e = next;
194 }
195
196 /* Check the values */
197 while (!IS_LAST_ENTRY(entry)) {
198 u32 size = le32_to_cpu(entry->e_value_size);
199
200 if (size > EXT4_XATTR_SIZE_MAX)
201 return -EFSCORRUPTED;
202
203 if (size != 0 && entry->e_value_inum == 0) {
204 u16 offs = le16_to_cpu(entry->e_value_offs);
205 void *value;
206
207 /*
208 * The value cannot overlap the names, and the value
209 * with padding cannot extend beyond 'end'. Check both
210 * the padded and unpadded sizes, since the size may
211 * overflow to 0 when adding padding.
212 */
213 if (offs > end - value_start)
214 return -EFSCORRUPTED;
215 value = value_start + offs;
216 if (value < (void *)e + sizeof(u32) ||
217 size > end - value ||
218 EXT4_XATTR_SIZE(size) > end - value)
219 return -EFSCORRUPTED;
220 }
221 entry = EXT4_XATTR_NEXT(entry);
222 }
223
224 return 0;
225}
226
227static inline int
228__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
229 const char *function, unsigned int line)
230{
231 int error = -EFSCORRUPTED;
232
233 if (buffer_verified(bh))
234 return 0;
235
236 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
237 BHDR(bh)->h_blocks != cpu_to_le32(1))
238 goto errout;
239 error = -EFSBADCRC;
240 if (!ext4_xattr_block_csum_verify(inode, bh))
241 goto errout;
242 error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
243 bh->b_data);
244errout:
245 if (error)
246 __ext4_error_inode(inode, function, line, 0,
247 "corrupted xattr block %llu",
248 (unsigned long long) bh->b_blocknr);
249 else
250 set_buffer_verified(bh);
251 return error;
252}
253
254#define ext4_xattr_check_block(inode, bh) \
255 __ext4_xattr_check_block((inode), (bh), __func__, __LINE__)
256
257
258static int
259__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
260 void *end, const char *function, unsigned int line)
261{
262 int error = -EFSCORRUPTED;
263
264 if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
265 (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
266 goto errout;
267 error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
268errout:
269 if (error)
270 __ext4_error_inode(inode, function, line, 0,
271 "corrupted in-inode xattr");
272 return error;
273}
274
275#define xattr_check_inode(inode, header, end) \
276 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
277
278static int
279xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
280 void *end, int name_index, const char *name, int sorted)
281{
282 struct ext4_xattr_entry *entry, *next;
283 size_t name_len;
284 int cmp = 1;
285
286 if (name == NULL)
287 return -EINVAL;
288 name_len = strlen(name);
289 for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
290 next = EXT4_XATTR_NEXT(entry);
291 if ((void *) next >= end) {
292 EXT4_ERROR_INODE(inode, "corrupted xattr entries");
293 return -EFSCORRUPTED;
294 }
295 cmp = name_index - entry->e_name_index;
296 if (!cmp)
297 cmp = name_len - entry->e_name_len;
298 if (!cmp)
299 cmp = memcmp(name, entry->e_name, name_len);
300 if (cmp <= 0 && (sorted || cmp == 0))
301 break;
302 }
303 *pentry = entry;
304 return cmp ? -ENODATA : 0;
305}
306
307static u32
308ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
309{
310 return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
311}
312
313static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
314{
315 return ((u64)ea_inode->i_ctime.tv_sec << 32) |
316 (u32) inode_peek_iversion_raw(ea_inode);
317}
318
319static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
320{
321 ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
322 inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
323}
324
325static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
326{
327 return (u32)ea_inode->i_atime.tv_sec;
328}
329
330static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
331{
332 ea_inode->i_atime.tv_sec = hash;
333}
334
335/*
336 * Read the EA value from an inode.
337 */
338static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
339{
340 int blocksize = 1 << ea_inode->i_blkbits;
341 int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
342 int tail_size = (size % blocksize) ?: blocksize;
343 struct buffer_head *bhs_inline[8];
344 struct buffer_head **bhs = bhs_inline;
345 int i, ret;
346
347 if (bh_count > ARRAY_SIZE(bhs_inline)) {
348 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
349 if (!bhs)
350 return -ENOMEM;
351 }
352
353 ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
354 true /* wait */, bhs);
355 if (ret)
356 goto free_bhs;
357
358 for (i = 0; i < bh_count; i++) {
359 /* There shouldn't be any holes in ea_inode. */
360 if (!bhs[i]) {
361 ret = -EFSCORRUPTED;
362 goto put_bhs;
363 }
364 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
365 i < bh_count - 1 ? blocksize : tail_size);
366 }
367 ret = 0;
368put_bhs:
369 for (i = 0; i < bh_count; i++)
370 brelse(bhs[i]);
371free_bhs:
372 if (bhs != bhs_inline)
373 kfree(bhs);
374 return ret;
375}
376
377#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
378
379static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
380 u32 ea_inode_hash, struct inode **ea_inode)
381{
382 struct inode *inode;
383 int err;
384
385 inode = ext4_iget(parent->i_sb, ea_ino);
386 if (IS_ERR(inode)) {
387 err = PTR_ERR(inode);
388 ext4_error(parent->i_sb,
389 "error while reading EA inode %lu err=%d", ea_ino,
390 err);
391 return err;
392 }
393
394 if (is_bad_inode(inode)) {
395 ext4_error(parent->i_sb,
396 "error while reading EA inode %lu is_bad_inode",
397 ea_ino);
398 err = -EIO;
399 goto error;
400 }
401
402 if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
403 ext4_error(parent->i_sb,
404 "EA inode %lu does not have EXT4_EA_INODE_FL flag",
405 ea_ino);
406 err = -EINVAL;
407 goto error;
408 }
409
410 ext4_xattr_inode_set_class(inode);
411
412 /*
413 * Check whether this is an old Lustre-style xattr inode. Lustre
414 * implementation does not have hash validation, rather it has a
415 * backpointer from ea_inode to the parent inode.
416 */
417 if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
418 EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
419 inode->i_generation == parent->i_generation) {
420 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
421 ext4_xattr_inode_set_ref(inode, 1);
422 } else {
423 inode_lock(inode);
424 inode->i_flags |= S_NOQUOTA;
425 inode_unlock(inode);
426 }
427
428 *ea_inode = inode;
429 return 0;
430error:
431 iput(inode);
432 return err;
433}
434
435static int
436ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
437 struct ext4_xattr_entry *entry, void *buffer,
438 size_t size)
439{
440 u32 hash;
441
442 /* Verify stored hash matches calculated hash. */
443 hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
444 if (hash != ext4_xattr_inode_get_hash(ea_inode))
445 return -EFSCORRUPTED;
446
447 if (entry) {
448 __le32 e_hash, tmp_data;
449
450 /* Verify entry hash. */
451 tmp_data = cpu_to_le32(hash);
452 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
453 &tmp_data, 1);
454 if (e_hash != entry->e_hash)
455 return -EFSCORRUPTED;
456 }
457 return 0;
458}
459
460/*
461 * Read xattr value from the EA inode.
462 */
463static int
464ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
465 void *buffer, size_t size)
466{
467 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
468 struct inode *ea_inode;
469 int err;
470
471 err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
472 le32_to_cpu(entry->e_hash), &ea_inode);
473 if (err) {
474 ea_inode = NULL;
475 goto out;
476 }
477
478 if (i_size_read(ea_inode) != size) {
479 ext4_warning_inode(ea_inode,
480 "ea_inode file size=%llu entry size=%zu",
481 i_size_read(ea_inode), size);
482 err = -EFSCORRUPTED;
483 goto out;
484 }
485
486 err = ext4_xattr_inode_read(ea_inode, buffer, size);
487 if (err)
488 goto out;
489
490 if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
491 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
492 size);
493 if (err) {
494 ext4_warning_inode(ea_inode,
495 "EA inode hash validation failed");
496 goto out;
497 }
498
499 if (ea_inode_cache)
500 mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
501 ext4_xattr_inode_get_hash(ea_inode),
502 ea_inode->i_ino, true /* reusable */);
503 }
504out:
505 iput(ea_inode);
506 return err;
507}
508
509static int
510ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
511 void *buffer, size_t buffer_size)
512{
513 struct buffer_head *bh = NULL;
514 struct ext4_xattr_entry *entry;
515 size_t size;
516 void *end;
517 int error;
518 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
519
520 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
521 name_index, name, buffer, (long)buffer_size);
522
523 error = -ENODATA;
524 if (!EXT4_I(inode)->i_file_acl)
525 goto cleanup;
526 ea_idebug(inode, "reading block %llu",
527 (unsigned long long)EXT4_I(inode)->i_file_acl);
528 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
529 if (!bh)
530 goto cleanup;
531 ea_bdebug(bh, "b_count=%d, refcount=%d",
532 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
533 error = ext4_xattr_check_block(inode, bh);
534 if (error)
535 goto cleanup;
536 ext4_xattr_block_cache_insert(ea_block_cache, bh);
537 entry = BFIRST(bh);
538 end = bh->b_data + bh->b_size;
539 error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
540 if (error)
541 goto cleanup;
542 size = le32_to_cpu(entry->e_value_size);
543 error = -ERANGE;
544 if (unlikely(size > EXT4_XATTR_SIZE_MAX))
545 goto cleanup;
546 if (buffer) {
547 if (size > buffer_size)
548 goto cleanup;
549 if (entry->e_value_inum) {
550 error = ext4_xattr_inode_get(inode, entry, buffer,
551 size);
552 if (error)
553 goto cleanup;
554 } else {
555 u16 offset = le16_to_cpu(entry->e_value_offs);
556 void *p = bh->b_data + offset;
557
558 if (unlikely(p + size > end))
559 goto cleanup;
560 memcpy(buffer, p, size);
561 }
562 }
563 error = size;
564
565cleanup:
566 brelse(bh);
567 return error;
568}
569
570int
571ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
572 void *buffer, size_t buffer_size)
573{
574 struct ext4_xattr_ibody_header *header;
575 struct ext4_xattr_entry *entry;
576 struct ext4_inode *raw_inode;
577 struct ext4_iloc iloc;
578 size_t size;
579 void *end;
580 int error;
581
582 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
583 return -ENODATA;
584 error = ext4_get_inode_loc(inode, &iloc);
585 if (error)
586 return error;
587 raw_inode = ext4_raw_inode(&iloc);
588 header = IHDR(inode, raw_inode);
589 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
590 error = xattr_check_inode(inode, header, end);
591 if (error)
592 goto cleanup;
593 entry = IFIRST(header);
594 error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
595 if (error)
596 goto cleanup;
597 size = le32_to_cpu(entry->e_value_size);
598 error = -ERANGE;
599 if (unlikely(size > EXT4_XATTR_SIZE_MAX))
600 goto cleanup;
601 if (buffer) {
602 if (size > buffer_size)
603 goto cleanup;
604 if (entry->e_value_inum) {
605 error = ext4_xattr_inode_get(inode, entry, buffer,
606 size);
607 if (error)
608 goto cleanup;
609 } else {
610 u16 offset = le16_to_cpu(entry->e_value_offs);
611 void *p = (void *)IFIRST(header) + offset;
612
613 if (unlikely(p + size > end))
614 goto cleanup;
615 memcpy(buffer, p, size);
616 }
617 }
618 error = size;
619
620cleanup:
621 brelse(iloc.bh);
622 return error;
623}
624
625/*
626 * ext4_xattr_get()
627 *
628 * Copy an extended attribute into the buffer
629 * provided, or compute the buffer size required.
630 * Buffer is NULL to compute the size of the buffer required.
631 *
632 * Returns a negative error number on failure, or the number of bytes
633 * used / required on success.
634 */
635int
636ext4_xattr_get(struct inode *inode, int name_index, const char *name,
637 void *buffer, size_t buffer_size)
638{
639 int error;
640
641 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
642 return -EIO;
643
644 if (strlen(name) > 255)
645 return -ERANGE;
646
647 down_read(&EXT4_I(inode)->xattr_sem);
648 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
649 buffer_size);
650 if (error == -ENODATA)
651 error = ext4_xattr_block_get(inode, name_index, name, buffer,
652 buffer_size);
653 up_read(&EXT4_I(inode)->xattr_sem);
654 return error;
655}
656
657static int
658ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
659 char *buffer, size_t buffer_size)
660{
661 size_t rest = buffer_size;
662
663 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
664 const struct xattr_handler *handler =
665 ext4_xattr_handler(entry->e_name_index);
666
667 if (handler && (!handler->list || handler->list(dentry))) {
668 const char *prefix = handler->prefix ?: handler->name;
669 size_t prefix_len = strlen(prefix);
670 size_t size = prefix_len + entry->e_name_len + 1;
671
672 if (buffer) {
673 if (size > rest)
674 return -ERANGE;
675 memcpy(buffer, prefix, prefix_len);
676 buffer += prefix_len;
677 memcpy(buffer, entry->e_name, entry->e_name_len);
678 buffer += entry->e_name_len;
679 *buffer++ = 0;
680 }
681 rest -= size;
682 }
683 }
684 return buffer_size - rest; /* total size */
685}
686
687static int
688ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
689{
690 struct inode *inode = d_inode(dentry);
691 struct buffer_head *bh = NULL;
692 int error;
693
694 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
695 buffer, (long)buffer_size);
696
697 error = 0;
698 if (!EXT4_I(inode)->i_file_acl)
699 goto cleanup;
700 ea_idebug(inode, "reading block %llu",
701 (unsigned long long)EXT4_I(inode)->i_file_acl);
702 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
703 error = -EIO;
704 if (!bh)
705 goto cleanup;
706 ea_bdebug(bh, "b_count=%d, refcount=%d",
707 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
708 error = ext4_xattr_check_block(inode, bh);
709 if (error)
710 goto cleanup;
711 ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
712 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
713
714cleanup:
715 brelse(bh);
716
717 return error;
718}
719
720static int
721ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
722{
723 struct inode *inode = d_inode(dentry);
724 struct ext4_xattr_ibody_header *header;
725 struct ext4_inode *raw_inode;
726 struct ext4_iloc iloc;
727 void *end;
728 int error;
729
730 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
731 return 0;
732 error = ext4_get_inode_loc(inode, &iloc);
733 if (error)
734 return error;
735 raw_inode = ext4_raw_inode(&iloc);
736 header = IHDR(inode, raw_inode);
737 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
738 error = xattr_check_inode(inode, header, end);
739 if (error)
740 goto cleanup;
741 error = ext4_xattr_list_entries(dentry, IFIRST(header),
742 buffer, buffer_size);
743
744cleanup:
745 brelse(iloc.bh);
746 return error;
747}
748
749/*
750 * Inode operation listxattr()
751 *
752 * d_inode(dentry)->i_rwsem: don't care
753 *
754 * Copy a list of attribute names into the buffer
755 * provided, or compute the buffer size required.
756 * Buffer is NULL to compute the size of the buffer required.
757 *
758 * Returns a negative error number on failure, or the number of bytes
759 * used / required on success.
760 */
761ssize_t
762ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
763{
764 int ret, ret2;
765
766 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
767 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
768 if (ret < 0)
769 goto errout;
770 if (buffer) {
771 buffer += ret;
772 buffer_size -= ret;
773 }
774 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
775 if (ret < 0)
776 goto errout;
777 ret += ret2;
778errout:
779 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
780 return ret;
781}
782
783/*
784 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
785 * not set, set it.
786 */
787static void ext4_xattr_update_super_block(handle_t *handle,
788 struct super_block *sb)
789{
790 if (ext4_has_feature_xattr(sb))
791 return;
792
793 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
794 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
795 ext4_set_feature_xattr(sb);
796 ext4_handle_dirty_super(handle, sb);
797 }
798}
799
800int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
801{
802 struct ext4_iloc iloc = { .bh = NULL };
803 struct buffer_head *bh = NULL;
804 struct ext4_inode *raw_inode;
805 struct ext4_xattr_ibody_header *header;
806 struct ext4_xattr_entry *entry;
807 qsize_t ea_inode_refs = 0;
808 void *end;
809 int ret;
810
811 lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
812
813 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
814 ret = ext4_get_inode_loc(inode, &iloc);
815 if (ret)
816 goto out;
817 raw_inode = ext4_raw_inode(&iloc);
818 header = IHDR(inode, raw_inode);
819 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
820 ret = xattr_check_inode(inode, header, end);
821 if (ret)
822 goto out;
823
824 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
825 entry = EXT4_XATTR_NEXT(entry))
826 if (entry->e_value_inum)
827 ea_inode_refs++;
828 }
829
830 if (EXT4_I(inode)->i_file_acl) {
831 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
832 if (!bh) {
833 ret = -EIO;
834 goto out;
835 }
836
837 ret = ext4_xattr_check_block(inode, bh);
838 if (ret)
839 goto out;
840
841 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
842 entry = EXT4_XATTR_NEXT(entry))
843 if (entry->e_value_inum)
844 ea_inode_refs++;
845 }
846 *usage = ea_inode_refs + 1;
847 ret = 0;
848out:
849 brelse(iloc.bh);
850 brelse(bh);
851 return ret;
852}
853
854static inline size_t round_up_cluster(struct inode *inode, size_t length)
855{
856 struct super_block *sb = inode->i_sb;
857 size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
858 inode->i_blkbits);
859 size_t mask = ~(cluster_size - 1);
860
861 return (length + cluster_size - 1) & mask;
862}
863
864static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
865{
866 int err;
867
868 err = dquot_alloc_inode(inode);
869 if (err)
870 return err;
871 err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
872 if (err)
873 dquot_free_inode(inode);
874 return err;
875}
876
877static void ext4_xattr_inode_free_quota(struct inode *parent,
878 struct inode *ea_inode,
879 size_t len)
880{
881 if (ea_inode &&
882 ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
883 return;
884 dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
885 dquot_free_inode(parent);
886}
887
888int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
889 struct buffer_head *block_bh, size_t value_len,
890 bool is_create)
891{
892 int credits;
893 int blocks;
894
895 /*
896 * 1) Owner inode update
897 * 2) Ref count update on old xattr block
898 * 3) new xattr block
899 * 4) block bitmap update for new xattr block
900 * 5) group descriptor for new xattr block
901 * 6) block bitmap update for old xattr block
902 * 7) group descriptor for old block
903 *
904 * 6 & 7 can happen if we have two racing threads T_a and T_b
905 * which are each trying to set an xattr on inodes I_a and I_b
906 * which were both initially sharing an xattr block.
907 */
908 credits = 7;
909
910 /* Quota updates. */
911 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
912
913 /*
914 * In case of inline data, we may push out the data to a block,
915 * so we need to reserve credits for this eventuality
916 */
917 if (inode && ext4_has_inline_data(inode))
918 credits += ext4_writepage_trans_blocks(inode) + 1;
919
920 /* We are done if ea_inode feature is not enabled. */
921 if (!ext4_has_feature_ea_inode(sb))
922 return credits;
923
924 /* New ea_inode, inode map, block bitmap, group descriptor. */
925 credits += 4;
926
927 /* Data blocks. */
928 blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
929
930 /* Indirection block or one level of extent tree. */
931 blocks += 1;
932
933 /* Block bitmap and group descriptor updates for each block. */
934 credits += blocks * 2;
935
936 /* Blocks themselves. */
937 credits += blocks;
938
939 if (!is_create) {
940 /* Dereference ea_inode holding old xattr value.
941 * Old ea_inode, inode map, block bitmap, group descriptor.
942 */
943 credits += 4;
944
945 /* Data blocks for old ea_inode. */
946 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
947
948 /* Indirection block or one level of extent tree for old
949 * ea_inode.
950 */
951 blocks += 1;
952
953 /* Block bitmap and group descriptor updates for each block. */
954 credits += blocks * 2;
955 }
956
957 /* We may need to clone the existing xattr block in which case we need
958 * to increment ref counts for existing ea_inodes referenced by it.
959 */
960 if (block_bh) {
961 struct ext4_xattr_entry *entry = BFIRST(block_bh);
962
963 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
964 if (entry->e_value_inum)
965 /* Ref count update on ea_inode. */
966 credits += 1;
967 }
968 return credits;
969}
970
971static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
972 int credits, struct buffer_head *bh,
973 bool dirty, bool block_csum)
974{
975 int error;
976
977 if (!ext4_handle_valid(handle))
978 return 0;
979
980 if (handle->h_buffer_credits >= credits)
981 return 0;
982
983 error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);
984 if (!error)
985 return 0;
986 if (error < 0) {
987 ext4_warning(inode->i_sb, "Extend journal (error %d)", error);
988 return error;
989 }
990
991 if (bh && dirty) {
992 if (block_csum)
993 ext4_xattr_block_csum_set(inode, bh);
994 error = ext4_handle_dirty_metadata(handle, NULL, bh);
995 if (error) {
996 ext4_warning(inode->i_sb, "Handle metadata (error %d)",
997 error);
998 return error;
999 }
1000 }
1001
1002 error = ext4_journal_restart(handle, credits);
1003 if (error) {
1004 ext4_warning(inode->i_sb, "Restart journal (error %d)", error);
1005 return error;
1006 }
1007
1008 if (bh) {
1009 error = ext4_journal_get_write_access(handle, bh);
1010 if (error) {
1011 ext4_warning(inode->i_sb,
1012 "Get write access failed (error %d)",
1013 error);
1014 return error;
1015 }
1016 }
1017 return 0;
1018}
1019
1020static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
1021 int ref_change)
1022{
1023 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
1024 struct ext4_iloc iloc;
1025 s64 ref_count;
1026 u32 hash;
1027 int ret;
1028
1029 inode_lock(ea_inode);
1030
1031 ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
1032 if (ret) {
1033 iloc.bh = NULL;
1034 goto out;
1035 }
1036
1037 ref_count = ext4_xattr_inode_get_ref(ea_inode);
1038 ref_count += ref_change;
1039 ext4_xattr_inode_set_ref(ea_inode, ref_count);
1040
1041 if (ref_change > 0) {
1042 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1043 ea_inode->i_ino, ref_count);
1044
1045 if (ref_count == 1) {
1046 WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1047 ea_inode->i_ino, ea_inode->i_nlink);
1048
1049 set_nlink(ea_inode, 1);
1050 ext4_orphan_del(handle, ea_inode);
1051
1052 if (ea_inode_cache) {
1053 hash = ext4_xattr_inode_get_hash(ea_inode);
1054 mb_cache_entry_create(ea_inode_cache,
1055 GFP_NOFS, hash,
1056 ea_inode->i_ino,
1057 true /* reusable */);
1058 }
1059 }
1060 } else {
1061 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1062 ea_inode->i_ino, ref_count);
1063
1064 if (ref_count == 0) {
1065 WARN_ONCE(ea_inode->i_nlink != 1,
1066 "EA inode %lu i_nlink=%u",
1067 ea_inode->i_ino, ea_inode->i_nlink);
1068
1069 clear_nlink(ea_inode);
1070 ext4_orphan_add(handle, ea_inode);
1071
1072 if (ea_inode_cache) {
1073 hash = ext4_xattr_inode_get_hash(ea_inode);
1074 mb_cache_entry_delete(ea_inode_cache, hash,
1075 ea_inode->i_ino);
1076 }
1077 }
1078 }
1079
1080 ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1081 iloc.bh = NULL;
1082 if (ret)
1083 ext4_warning_inode(ea_inode,
1084 "ext4_mark_iloc_dirty() failed ret=%d", ret);
1085out:
1086 brelse(iloc.bh);
1087 inode_unlock(ea_inode);
1088 return ret;
1089}
1090
1091static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1092{
1093 return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1094}
1095
1096static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1097{
1098 return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1099}
1100
1101static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1102 struct ext4_xattr_entry *first)
1103{
1104 struct inode *ea_inode;
1105 struct ext4_xattr_entry *entry;
1106 struct ext4_xattr_entry *failed_entry;
1107 unsigned int ea_ino;
1108 int err, saved_err;
1109
1110 for (entry = first; !IS_LAST_ENTRY(entry);
1111 entry = EXT4_XATTR_NEXT(entry)) {
1112 if (!entry->e_value_inum)
1113 continue;
1114 ea_ino = le32_to_cpu(entry->e_value_inum);
1115 err = ext4_xattr_inode_iget(parent, ea_ino,
1116 le32_to_cpu(entry->e_hash),
1117 &ea_inode);
1118 if (err)
1119 goto cleanup;
1120 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1121 if (err) {
1122 ext4_warning_inode(ea_inode, "inc ref error %d", err);
1123 iput(ea_inode);
1124 goto cleanup;
1125 }
1126 iput(ea_inode);
1127 }
1128 return 0;
1129
1130cleanup:
1131 saved_err = err;
1132 failed_entry = entry;
1133
1134 for (entry = first; entry != failed_entry;
1135 entry = EXT4_XATTR_NEXT(entry)) {
1136 if (!entry->e_value_inum)
1137 continue;
1138 ea_ino = le32_to_cpu(entry->e_value_inum);
1139 err = ext4_xattr_inode_iget(parent, ea_ino,
1140 le32_to_cpu(entry->e_hash),
1141 &ea_inode);
1142 if (err) {
1143 ext4_warning(parent->i_sb,
1144 "cleanup ea_ino %u iget error %d", ea_ino,
1145 err);
1146 continue;
1147 }
1148 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1149 if (err)
1150 ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1151 err);
1152 iput(ea_inode);
1153 }
1154 return saved_err;
1155}
1156
1157static void
1158ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1159 struct buffer_head *bh,
1160 struct ext4_xattr_entry *first, bool block_csum,
1161 struct ext4_xattr_inode_array **ea_inode_array,
1162 int extra_credits, bool skip_quota)
1163{
1164 struct inode *ea_inode;
1165 struct ext4_xattr_entry *entry;
1166 bool dirty = false;
1167 unsigned int ea_ino;
1168 int err;
1169 int credits;
1170
1171 /* One credit for dec ref on ea_inode, one for orphan list addition, */
1172 credits = 2 + extra_credits;
1173
1174 for (entry = first; !IS_LAST_ENTRY(entry);
1175 entry = EXT4_XATTR_NEXT(entry)) {
1176 if (!entry->e_value_inum)
1177 continue;
1178 ea_ino = le32_to_cpu(entry->e_value_inum);
1179 err = ext4_xattr_inode_iget(parent, ea_ino,
1180 le32_to_cpu(entry->e_hash),
1181 &ea_inode);
1182 if (err)
1183 continue;
1184
1185 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1186 if (err) {
1187 ext4_warning_inode(ea_inode,
1188 "Expand inode array err=%d", err);
1189 iput(ea_inode);
1190 continue;
1191 }
1192
1193 err = ext4_xattr_ensure_credits(handle, parent, credits, bh,
1194 dirty, block_csum);
1195 if (err) {
1196 ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1197 err);
1198 continue;
1199 }
1200
1201 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1202 if (err) {
1203 ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1204 err);
1205 continue;
1206 }
1207
1208 if (!skip_quota)
1209 ext4_xattr_inode_free_quota(parent, ea_inode,
1210 le32_to_cpu(entry->e_value_size));
1211
1212 /*
1213 * Forget about ea_inode within the same transaction that
1214 * decrements the ref count. This avoids duplicate decrements in
1215 * case the rest of the work spills over to subsequent
1216 * transactions.
1217 */
1218 entry->e_value_inum = 0;
1219 entry->e_value_size = 0;
1220
1221 dirty = true;
1222 }
1223
1224 if (dirty) {
1225 /*
1226 * Note that we are deliberately skipping csum calculation for
1227 * the final update because we do not expect any journal
1228 * restarts until xattr block is freed.
1229 */
1230
1231 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1232 if (err)
1233 ext4_warning_inode(parent,
1234 "handle dirty metadata err=%d", err);
1235 }
1236}
1237
1238/*
1239 * Release the xattr block BH: If the reference count is > 1, decrement it;
1240 * otherwise free the block.
1241 */
1242static void
1243ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1244 struct buffer_head *bh,
1245 struct ext4_xattr_inode_array **ea_inode_array,
1246 int extra_credits)
1247{
1248 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1249 u32 hash, ref;
1250 int error = 0;
1251
1252 BUFFER_TRACE(bh, "get_write_access");
1253 error = ext4_journal_get_write_access(handle, bh);
1254 if (error)
1255 goto out;
1256
1257 lock_buffer(bh);
1258 hash = le32_to_cpu(BHDR(bh)->h_hash);
1259 ref = le32_to_cpu(BHDR(bh)->h_refcount);
1260 if (ref == 1) {
1261 ea_bdebug(bh, "refcount now=0; freeing");
1262 /*
1263 * This must happen under buffer lock for
1264 * ext4_xattr_block_set() to reliably detect freed block
1265 */
1266 if (ea_block_cache)
1267 mb_cache_entry_delete(ea_block_cache, hash,
1268 bh->b_blocknr);
1269 get_bh(bh);
1270 unlock_buffer(bh);
1271
1272 if (ext4_has_feature_ea_inode(inode->i_sb))
1273 ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1274 BFIRST(bh),
1275 true /* block_csum */,
1276 ea_inode_array,
1277 extra_credits,
1278 true /* skip_quota */);
1279 ext4_free_blocks(handle, inode, bh, 0, 1,
1280 EXT4_FREE_BLOCKS_METADATA |
1281 EXT4_FREE_BLOCKS_FORGET);
1282 } else {
1283 ref--;
1284 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1285 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1286 struct mb_cache_entry *ce;
1287
1288 if (ea_block_cache) {
1289 ce = mb_cache_entry_get(ea_block_cache, hash,
1290 bh->b_blocknr);
1291 if (ce) {
1292 ce->e_reusable = 1;
1293 mb_cache_entry_put(ea_block_cache, ce);
1294 }
1295 }
1296 }
1297
1298 ext4_xattr_block_csum_set(inode, bh);
1299 /*
1300 * Beware of this ugliness: Releasing of xattr block references
1301 * from different inodes can race and so we have to protect
1302 * from a race where someone else frees the block (and releases
1303 * its journal_head) before we are done dirtying the buffer. In
1304 * nojournal mode this race is harmless and we actually cannot
1305 * call ext4_handle_dirty_metadata() with locked buffer as
1306 * that function can call sync_dirty_buffer() so for that case
1307 * we handle the dirtying after unlocking the buffer.
1308 */
1309 if (ext4_handle_valid(handle))
1310 error = ext4_handle_dirty_metadata(handle, inode, bh);
1311 unlock_buffer(bh);
1312 if (!ext4_handle_valid(handle))
1313 error = ext4_handle_dirty_metadata(handle, inode, bh);
1314 if (IS_SYNC(inode))
1315 ext4_handle_sync(handle);
1316 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1317 ea_bdebug(bh, "refcount now=%d; releasing",
1318 le32_to_cpu(BHDR(bh)->h_refcount));
1319 }
1320out:
1321 ext4_std_error(inode->i_sb, error);
1322 return;
1323}
1324
1325/*
1326 * Find the available free space for EAs. This also returns the total number of
1327 * bytes used by EA entries.
1328 */
1329static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1330 size_t *min_offs, void *base, int *total)
1331{
1332 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1333 if (!last->e_value_inum && last->e_value_size) {
1334 size_t offs = le16_to_cpu(last->e_value_offs);
1335 if (offs < *min_offs)
1336 *min_offs = offs;
1337 }
1338 if (total)
1339 *total += EXT4_XATTR_LEN(last->e_name_len);
1340 }
1341 return (*min_offs - ((void *)last - base) - sizeof(__u32));
1342}
1343
1344/*
1345 * Write the value of the EA in an inode.
1346 */
1347static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1348 const void *buf, int bufsize)
1349{
1350 struct buffer_head *bh = NULL;
1351 unsigned long block = 0;
1352 int blocksize = ea_inode->i_sb->s_blocksize;
1353 int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1354 int csize, wsize = 0;
1355 int ret = 0;
1356 int retries = 0;
1357
1358retry:
1359 while (ret >= 0 && ret < max_blocks) {
1360 struct ext4_map_blocks map;
1361 map.m_lblk = block += ret;
1362 map.m_len = max_blocks -= ret;
1363
1364 ret = ext4_map_blocks(handle, ea_inode, &map,
1365 EXT4_GET_BLOCKS_CREATE);
1366 if (ret <= 0) {
1367 ext4_mark_inode_dirty(handle, ea_inode);
1368 if (ret == -ENOSPC &&
1369 ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1370 ret = 0;
1371 goto retry;
1372 }
1373 break;
1374 }
1375 }
1376
1377 if (ret < 0)
1378 return ret;
1379
1380 block = 0;
1381 while (wsize < bufsize) {
1382 if (bh != NULL)
1383 brelse(bh);
1384 csize = (bufsize - wsize) > blocksize ? blocksize :
1385 bufsize - wsize;
1386 bh = ext4_getblk(handle, ea_inode, block, 0);
1387 if (IS_ERR(bh))
1388 return PTR_ERR(bh);
1389 ret = ext4_journal_get_write_access(handle, bh);
1390 if (ret)
1391 goto out;
1392
1393 memcpy(bh->b_data, buf, csize);
1394 set_buffer_uptodate(bh);
1395 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1396
1397 buf += csize;
1398 wsize += csize;
1399 block += 1;
1400 }
1401
1402 inode_lock(ea_inode);
1403 i_size_write(ea_inode, wsize);
1404 ext4_update_i_disksize(ea_inode, wsize);
1405 inode_unlock(ea_inode);
1406
1407 ext4_mark_inode_dirty(handle, ea_inode);
1408
1409out:
1410 brelse(bh);
1411
1412 return ret;
1413}
1414
1415/*
1416 * Create an inode to store the value of a large EA.
1417 */
1418static struct inode *ext4_xattr_inode_create(handle_t *handle,
1419 struct inode *inode, u32 hash)
1420{
1421 struct inode *ea_inode = NULL;
1422 uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1423 int err;
1424
1425 /*
1426 * Let the next inode be the goal, so we try and allocate the EA inode
1427 * in the same group, or nearby one.
1428 */
1429 ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1430 S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1431 EXT4_EA_INODE_FL);
1432 if (!IS_ERR(ea_inode)) {
1433 ea_inode->i_op = &ext4_file_inode_operations;
1434 ea_inode->i_fop = &ext4_file_operations;
1435 ext4_set_aops(ea_inode);
1436 ext4_xattr_inode_set_class(ea_inode);
1437 unlock_new_inode(ea_inode);
1438 ext4_xattr_inode_set_ref(ea_inode, 1);
1439 ext4_xattr_inode_set_hash(ea_inode, hash);
1440 err = ext4_mark_inode_dirty(handle, ea_inode);
1441 if (!err)
1442 err = ext4_inode_attach_jinode(ea_inode);
1443 if (err) {
1444 iput(ea_inode);
1445 return ERR_PTR(err);
1446 }
1447
1448 /*
1449 * Xattr inodes are shared therefore quota charging is performed
1450 * at a higher level.
1451 */
1452 dquot_free_inode(ea_inode);
1453 dquot_drop(ea_inode);
1454 inode_lock(ea_inode);
1455 ea_inode->i_flags |= S_NOQUOTA;
1456 inode_unlock(ea_inode);
1457 }
1458
1459 return ea_inode;
1460}
1461
1462static struct inode *
1463ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1464 size_t value_len, u32 hash)
1465{
1466 struct inode *ea_inode;
1467 struct mb_cache_entry *ce;
1468 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1469 void *ea_data;
1470
1471 if (!ea_inode_cache)
1472 return NULL;
1473
1474 ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1475 if (!ce)
1476 return NULL;
1477
1478 ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
1479 if (!ea_data) {
1480 mb_cache_entry_put(ea_inode_cache, ce);
1481 return NULL;
1482 }
1483
1484 while (ce) {
1485 ea_inode = ext4_iget(inode->i_sb, ce->e_value);
1486 if (!IS_ERR(ea_inode) &&
1487 !is_bad_inode(ea_inode) &&
1488 (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1489 i_size_read(ea_inode) == value_len &&
1490 !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1491 !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1492 value_len) &&
1493 !memcmp(value, ea_data, value_len)) {
1494 mb_cache_entry_touch(ea_inode_cache, ce);
1495 mb_cache_entry_put(ea_inode_cache, ce);
1496 kvfree(ea_data);
1497 return ea_inode;
1498 }
1499
1500 if (!IS_ERR(ea_inode))
1501 iput(ea_inode);
1502 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1503 }
1504 kvfree(ea_data);
1505 return NULL;
1506}
1507
1508/*
1509 * Add value of the EA in an inode.
1510 */
1511static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1512 const void *value, size_t value_len,
1513 struct inode **ret_inode)
1514{
1515 struct inode *ea_inode;
1516 u32 hash;
1517 int err;
1518
1519 hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1520 ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1521 if (ea_inode) {
1522 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1523 if (err) {
1524 iput(ea_inode);
1525 return err;
1526 }
1527
1528 *ret_inode = ea_inode;
1529 return 0;
1530 }
1531
1532 /* Create an inode for the EA value */
1533 ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1534 if (IS_ERR(ea_inode))
1535 return PTR_ERR(ea_inode);
1536
1537 err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1538 if (err) {
1539 ext4_xattr_inode_dec_ref(handle, ea_inode);
1540 iput(ea_inode);
1541 return err;
1542 }
1543
1544 if (EA_INODE_CACHE(inode))
1545 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1546 ea_inode->i_ino, true /* reusable */);
1547
1548 *ret_inode = ea_inode;
1549 return 0;
1550}
1551
1552/*
1553 * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1554 * feature is enabled.
1555 */
1556#define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1557
1558static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1559 struct ext4_xattr_search *s,
1560 handle_t *handle, struct inode *inode,
1561 bool is_block)
1562{
1563 struct ext4_xattr_entry *last;
1564 struct ext4_xattr_entry *here = s->here;
1565 size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1566 int in_inode = i->in_inode;
1567 struct inode *old_ea_inode = NULL;
1568 struct inode *new_ea_inode = NULL;
1569 size_t old_size, new_size;
1570 int ret;
1571
1572 /* Space used by old and new values. */
1573 old_size = (!s->not_found && !here->e_value_inum) ?
1574 EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1575 new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1576
1577 /*
1578 * Optimization for the simple case when old and new values have the
1579 * same padded sizes. Not applicable if external inodes are involved.
1580 */
1581 if (new_size && new_size == old_size) {
1582 size_t offs = le16_to_cpu(here->e_value_offs);
1583 void *val = s->base + offs;
1584
1585 here->e_value_size = cpu_to_le32(i->value_len);
1586 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1587 memset(val, 0, new_size);
1588 } else {
1589 memcpy(val, i->value, i->value_len);
1590 /* Clear padding bytes. */
1591 memset(val + i->value_len, 0, new_size - i->value_len);
1592 }
1593 goto update_hash;
1594 }
1595
1596 /* Compute min_offs and last. */
1597 last = s->first;
1598 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1599 if (!last->e_value_inum && last->e_value_size) {
1600 size_t offs = le16_to_cpu(last->e_value_offs);
1601 if (offs < min_offs)
1602 min_offs = offs;
1603 }
1604 }
1605
1606 /* Check whether we have enough space. */
1607 if (i->value) {
1608 size_t free;
1609
1610 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1611 if (!s->not_found)
1612 free += EXT4_XATTR_LEN(name_len) + old_size;
1613
1614 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1615 ret = -ENOSPC;
1616 goto out;
1617 }
1618
1619 /*
1620 * If storing the value in an external inode is an option,
1621 * reserve space for xattr entries/names in the external
1622 * attribute block so that a long value does not occupy the
1623 * whole space and prevent futher entries being added.
1624 */
1625 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1626 new_size && is_block &&
1627 (min_offs + old_size - new_size) <
1628 EXT4_XATTR_BLOCK_RESERVE(inode)) {
1629 ret = -ENOSPC;
1630 goto out;
1631 }
1632 }
1633
1634 /*
1635 * Getting access to old and new ea inodes is subject to failures.
1636 * Finish that work before doing any modifications to the xattr data.
1637 */
1638 if (!s->not_found && here->e_value_inum) {
1639 ret = ext4_xattr_inode_iget(inode,
1640 le32_to_cpu(here->e_value_inum),
1641 le32_to_cpu(here->e_hash),
1642 &old_ea_inode);
1643 if (ret) {
1644 old_ea_inode = NULL;
1645 goto out;
1646 }
1647 }
1648 if (i->value && in_inode) {
1649 WARN_ON_ONCE(!i->value_len);
1650
1651 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1652 if (ret)
1653 goto out;
1654
1655 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1656 i->value_len,
1657 &new_ea_inode);
1658 if (ret) {
1659 new_ea_inode = NULL;
1660 ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1661 goto out;
1662 }
1663 }
1664
1665 if (old_ea_inode) {
1666 /* We are ready to release ref count on the old_ea_inode. */
1667 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1668 if (ret) {
1669 /* Release newly required ref count on new_ea_inode. */
1670 if (new_ea_inode) {
1671 int err;
1672
1673 err = ext4_xattr_inode_dec_ref(handle,
1674 new_ea_inode);
1675 if (err)
1676 ext4_warning_inode(new_ea_inode,
1677 "dec ref new_ea_inode err=%d",
1678 err);
1679 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1680 i->value_len);
1681 }
1682 goto out;
1683 }
1684
1685 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1686 le32_to_cpu(here->e_value_size));
1687 }
1688
1689 /* No failures allowed past this point. */
1690
1691 if (!s->not_found && here->e_value_offs) {
1692 /* Remove the old value. */
1693 void *first_val = s->base + min_offs;
1694 size_t offs = le16_to_cpu(here->e_value_offs);
1695 void *val = s->base + offs;
1696
1697 memmove(first_val + old_size, first_val, val - first_val);
1698 memset(first_val, 0, old_size);
1699 min_offs += old_size;
1700
1701 /* Adjust all value offsets. */
1702 last = s->first;
1703 while (!IS_LAST_ENTRY(last)) {
1704 size_t o = le16_to_cpu(last->e_value_offs);
1705
1706 if (!last->e_value_inum &&
1707 last->e_value_size && o < offs)
1708 last->e_value_offs = cpu_to_le16(o + old_size);
1709 last = EXT4_XATTR_NEXT(last);
1710 }
1711 }
1712
1713 if (!i->value) {
1714 /* Remove old name. */
1715 size_t size = EXT4_XATTR_LEN(name_len);
1716
1717 last = ENTRY((void *)last - size);
1718 memmove(here, (void *)here + size,
1719 (void *)last - (void *)here + sizeof(__u32));
1720 memset(last, 0, size);
1721 } else if (s->not_found) {
1722 /* Insert new name. */
1723 size_t size = EXT4_XATTR_LEN(name_len);
1724 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1725
1726 memmove((void *)here + size, here, rest);
1727 memset(here, 0, size);
1728 here->e_name_index = i->name_index;
1729 here->e_name_len = name_len;
1730 memcpy(here->e_name, i->name, name_len);
1731 } else {
1732 /* This is an update, reset value info. */
1733 here->e_value_inum = 0;
1734 here->e_value_offs = 0;
1735 here->e_value_size = 0;
1736 }
1737
1738 if (i->value) {
1739 /* Insert new value. */
1740 if (in_inode) {
1741 here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1742 } else if (i->value_len) {
1743 void *val = s->base + min_offs - new_size;
1744
1745 here->e_value_offs = cpu_to_le16(min_offs - new_size);
1746 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1747 memset(val, 0, new_size);
1748 } else {
1749 memcpy(val, i->value, i->value_len);
1750 /* Clear padding bytes. */
1751 memset(val + i->value_len, 0,
1752 new_size - i->value_len);
1753 }
1754 }
1755 here->e_value_size = cpu_to_le32(i->value_len);
1756 }
1757
1758update_hash:
1759 if (i->value) {
1760 __le32 hash = 0;
1761
1762 /* Entry hash calculation. */
1763 if (in_inode) {
1764 __le32 crc32c_hash;
1765
1766 /*
1767 * Feed crc32c hash instead of the raw value for entry
1768 * hash calculation. This is to avoid walking
1769 * potentially long value buffer again.
1770 */
1771 crc32c_hash = cpu_to_le32(
1772 ext4_xattr_inode_get_hash(new_ea_inode));
1773 hash = ext4_xattr_hash_entry(here->e_name,
1774 here->e_name_len,
1775 &crc32c_hash, 1);
1776 } else if (is_block) {
1777 __le32 *value = s->base + le16_to_cpu(
1778 here->e_value_offs);
1779
1780 hash = ext4_xattr_hash_entry(here->e_name,
1781 here->e_name_len, value,
1782 new_size >> 2);
1783 }
1784 here->e_hash = hash;
1785 }
1786
1787 if (is_block)
1788 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1789
1790 ret = 0;
1791out:
1792 iput(old_ea_inode);
1793 iput(new_ea_inode);
1794 return ret;
1795}
1796
1797struct ext4_xattr_block_find {
1798 struct ext4_xattr_search s;
1799 struct buffer_head *bh;
1800};
1801
1802static int
1803ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1804 struct ext4_xattr_block_find *bs)
1805{
1806 struct super_block *sb = inode->i_sb;
1807 int error;
1808
1809 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1810 i->name_index, i->name, i->value, (long)i->value_len);
1811
1812 if (EXT4_I(inode)->i_file_acl) {
1813 /* The inode already has an extended attribute block. */
1814 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
1815 error = -EIO;
1816 if (!bs->bh)
1817 goto cleanup;
1818 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1819 atomic_read(&(bs->bh->b_count)),
1820 le32_to_cpu(BHDR(bs->bh)->h_refcount));
1821 error = ext4_xattr_check_block(inode, bs->bh);
1822 if (error)
1823 goto cleanup;
1824 /* Find the named attribute. */
1825 bs->s.base = BHDR(bs->bh);
1826 bs->s.first = BFIRST(bs->bh);
1827 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1828 bs->s.here = bs->s.first;
1829 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1830 i->name_index, i->name, 1);
1831 if (error && error != -ENODATA)
1832 goto cleanup;
1833 bs->s.not_found = error;
1834 }
1835 error = 0;
1836
1837cleanup:
1838 return error;
1839}
1840
1841static int
1842ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1843 struct ext4_xattr_info *i,
1844 struct ext4_xattr_block_find *bs)
1845{
1846 struct super_block *sb = inode->i_sb;
1847 struct buffer_head *new_bh = NULL;
1848 struct ext4_xattr_search s_copy = bs->s;
1849 struct ext4_xattr_search *s = &s_copy;
1850 struct mb_cache_entry *ce = NULL;
1851 int error = 0;
1852 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1853 struct inode *ea_inode = NULL, *tmp_inode;
1854 size_t old_ea_inode_quota = 0;
1855 unsigned int ea_ino;
1856
1857
1858#define header(x) ((struct ext4_xattr_header *)(x))
1859
1860 if (s->base) {
1861 BUFFER_TRACE(bs->bh, "get_write_access");
1862 error = ext4_journal_get_write_access(handle, bs->bh);
1863 if (error)
1864 goto cleanup;
1865 lock_buffer(bs->bh);
1866
1867 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1868 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1869
1870 /*
1871 * This must happen under buffer lock for
1872 * ext4_xattr_block_set() to reliably detect modified
1873 * block
1874 */
1875 if (ea_block_cache)
1876 mb_cache_entry_delete(ea_block_cache, hash,
1877 bs->bh->b_blocknr);
1878 ea_bdebug(bs->bh, "modifying in-place");
1879 error = ext4_xattr_set_entry(i, s, handle, inode,
1880 true /* is_block */);
1881 ext4_xattr_block_csum_set(inode, bs->bh);
1882 unlock_buffer(bs->bh);
1883 if (error == -EFSCORRUPTED)
1884 goto bad_block;
1885 if (!error)
1886 error = ext4_handle_dirty_metadata(handle,
1887 inode,
1888 bs->bh);
1889 if (error)
1890 goto cleanup;
1891 goto inserted;
1892 } else {
1893 int offset = (char *)s->here - bs->bh->b_data;
1894
1895 unlock_buffer(bs->bh);
1896 ea_bdebug(bs->bh, "cloning");
1897 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1898 error = -ENOMEM;
1899 if (s->base == NULL)
1900 goto cleanup;
1901 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1902 s->first = ENTRY(header(s->base)+1);
1903 header(s->base)->h_refcount = cpu_to_le32(1);
1904 s->here = ENTRY(s->base + offset);
1905 s->end = s->base + bs->bh->b_size;
1906
1907 /*
1908 * If existing entry points to an xattr inode, we need
1909 * to prevent ext4_xattr_set_entry() from decrementing
1910 * ref count on it because the reference belongs to the
1911 * original block. In this case, make the entry look
1912 * like it has an empty value.
1913 */
1914 if (!s->not_found && s->here->e_value_inum) {
1915 ea_ino = le32_to_cpu(s->here->e_value_inum);
1916 error = ext4_xattr_inode_iget(inode, ea_ino,
1917 le32_to_cpu(s->here->e_hash),
1918 &tmp_inode);
1919 if (error)
1920 goto cleanup;
1921
1922 if (!ext4_test_inode_state(tmp_inode,
1923 EXT4_STATE_LUSTRE_EA_INODE)) {
1924 /*
1925 * Defer quota free call for previous
1926 * inode until success is guaranteed.
1927 */
1928 old_ea_inode_quota = le32_to_cpu(
1929 s->here->e_value_size);
1930 }
1931 iput(tmp_inode);
1932
1933 s->here->e_value_inum = 0;
1934 s->here->e_value_size = 0;
1935 }
1936 }
1937 } else {
1938 /* Allocate a buffer where we construct the new block. */
1939 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1940 /* assert(header == s->base) */
1941 error = -ENOMEM;
1942 if (s->base == NULL)
1943 goto cleanup;
1944 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1945 header(s->base)->h_blocks = cpu_to_le32(1);
1946 header(s->base)->h_refcount = cpu_to_le32(1);
1947 s->first = ENTRY(header(s->base)+1);
1948 s->here = ENTRY(header(s->base)+1);
1949 s->end = s->base + sb->s_blocksize;
1950 }
1951
1952 error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1953 if (error == -EFSCORRUPTED)
1954 goto bad_block;
1955 if (error)
1956 goto cleanup;
1957
1958 if (i->value && s->here->e_value_inum) {
1959 /*
1960 * A ref count on ea_inode has been taken as part of the call to
1961 * ext4_xattr_set_entry() above. We would like to drop this
1962 * extra ref but we have to wait until the xattr block is
1963 * initialized and has its own ref count on the ea_inode.
1964 */
1965 ea_ino = le32_to_cpu(s->here->e_value_inum);
1966 error = ext4_xattr_inode_iget(inode, ea_ino,
1967 le32_to_cpu(s->here->e_hash),
1968 &ea_inode);
1969 if (error) {
1970 ea_inode = NULL;
1971 goto cleanup;
1972 }
1973 }
1974
1975inserted:
1976 if (!IS_LAST_ENTRY(s->first)) {
1977 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1978 &ce);
1979 if (new_bh) {
1980 /* We found an identical block in the cache. */
1981 if (new_bh == bs->bh)
1982 ea_bdebug(new_bh, "keeping");
1983 else {
1984 u32 ref;
1985
1986 WARN_ON_ONCE(dquot_initialize_needed(inode));
1987
1988 /* The old block is released after updating
1989 the inode. */
1990 error = dquot_alloc_block(inode,
1991 EXT4_C2B(EXT4_SB(sb), 1));
1992 if (error)
1993 goto cleanup;
1994 BUFFER_TRACE(new_bh, "get_write_access");
1995 error = ext4_journal_get_write_access(handle,
1996 new_bh);
1997 if (error)
1998 goto cleanup_dquot;
1999 lock_buffer(new_bh);
2000 /*
2001 * We have to be careful about races with
2002 * freeing, rehashing or adding references to
2003 * xattr block. Once we hold buffer lock xattr
2004 * block's state is stable so we can check
2005 * whether the block got freed / rehashed or
2006 * not. Since we unhash mbcache entry under
2007 * buffer lock when freeing / rehashing xattr
2008 * block, checking whether entry is still
2009 * hashed is reliable. Same rules hold for
2010 * e_reusable handling.
2011 */
2012 if (hlist_bl_unhashed(&ce->e_hash_list) ||
2013 !ce->e_reusable) {
2014 /*
2015 * Undo everything and check mbcache
2016 * again.
2017 */
2018 unlock_buffer(new_bh);
2019 dquot_free_block(inode,
2020 EXT4_C2B(EXT4_SB(sb),
2021 1));
2022 brelse(new_bh);
2023 mb_cache_entry_put(ea_block_cache, ce);
2024 ce = NULL;
2025 new_bh = NULL;
2026 goto inserted;
2027 }
2028 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2029 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2030 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2031 ce->e_reusable = 0;
2032 ea_bdebug(new_bh, "reusing; refcount now=%d",
2033 ref);
2034 ext4_xattr_block_csum_set(inode, new_bh);
2035 unlock_buffer(new_bh);
2036 error = ext4_handle_dirty_metadata(handle,
2037 inode,
2038 new_bh);
2039 if (error)
2040 goto cleanup_dquot;
2041 }
2042 mb_cache_entry_touch(ea_block_cache, ce);
2043 mb_cache_entry_put(ea_block_cache, ce);
2044 ce = NULL;
2045 } else if (bs->bh && s->base == bs->bh->b_data) {
2046 /* We were modifying this block in-place. */
2047 ea_bdebug(bs->bh, "keeping this block");
2048 ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2049 new_bh = bs->bh;
2050 get_bh(new_bh);
2051 } else {
2052 /* We need to allocate a new block */
2053 ext4_fsblk_t goal, block;
2054
2055 WARN_ON_ONCE(dquot_initialize_needed(inode));
2056
2057 goal = ext4_group_first_block_no(sb,
2058 EXT4_I(inode)->i_block_group);
2059
2060 /* non-extent files can't have physical blocks past 2^32 */
2061 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2062 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2063
2064 block = ext4_new_meta_blocks(handle, inode, goal, 0,
2065 NULL, &error);
2066 if (error)
2067 goto cleanup;
2068
2069 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2070 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2071
2072 ea_idebug(inode, "creating block %llu",
2073 (unsigned long long)block);
2074
2075 new_bh = sb_getblk(sb, block);
2076 if (unlikely(!new_bh)) {
2077 error = -ENOMEM;
2078getblk_failed:
2079 ext4_free_blocks(handle, inode, NULL, block, 1,
2080 EXT4_FREE_BLOCKS_METADATA);
2081 goto cleanup;
2082 }
2083 error = ext4_xattr_inode_inc_ref_all(handle, inode,
2084 ENTRY(header(s->base)+1));
2085 if (error)
2086 goto getblk_failed;
2087 if (ea_inode) {
2088 /* Drop the extra ref on ea_inode. */
2089 error = ext4_xattr_inode_dec_ref(handle,
2090 ea_inode);
2091 if (error)
2092 ext4_warning_inode(ea_inode,
2093 "dec ref error=%d",
2094 error);
2095 iput(ea_inode);
2096 ea_inode = NULL;
2097 }
2098
2099 lock_buffer(new_bh);
2100 error = ext4_journal_get_create_access(handle, new_bh);
2101 if (error) {
2102 unlock_buffer(new_bh);
2103 error = -EIO;
2104 goto getblk_failed;
2105 }
2106 memcpy(new_bh->b_data, s->base, new_bh->b_size);
2107 ext4_xattr_block_csum_set(inode, new_bh);
2108 set_buffer_uptodate(new_bh);
2109 unlock_buffer(new_bh);
2110 ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2111 error = ext4_handle_dirty_metadata(handle, inode,
2112 new_bh);
2113 if (error)
2114 goto cleanup;
2115 }
2116 }
2117
2118 if (old_ea_inode_quota)
2119 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2120
2121 /* Update the inode. */
2122 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2123
2124 /* Drop the previous xattr block. */
2125 if (bs->bh && bs->bh != new_bh) {
2126 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2127
2128 ext4_xattr_release_block(handle, inode, bs->bh,
2129 &ea_inode_array,
2130 0 /* extra_credits */);
2131 ext4_xattr_inode_array_free(ea_inode_array);
2132 }
2133 error = 0;
2134
2135cleanup:
2136 if (ea_inode) {
2137 int error2;
2138
2139 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2140 if (error2)
2141 ext4_warning_inode(ea_inode, "dec ref error=%d",
2142 error2);
2143
2144 /* If there was an error, revert the quota charge. */
2145 if (error)
2146 ext4_xattr_inode_free_quota(inode, ea_inode,
2147 i_size_read(ea_inode));
2148 iput(ea_inode);
2149 }
2150 if (ce)
2151 mb_cache_entry_put(ea_block_cache, ce);
2152 brelse(new_bh);
2153 if (!(bs->bh && s->base == bs->bh->b_data))
2154 kfree(s->base);
2155
2156 return error;
2157
2158cleanup_dquot:
2159 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2160 goto cleanup;
2161
2162bad_block:
2163 EXT4_ERROR_INODE(inode, "bad block %llu",
2164 EXT4_I(inode)->i_file_acl);
2165 goto cleanup;
2166
2167#undef header
2168}
2169
2170int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2171 struct ext4_xattr_ibody_find *is)
2172{
2173 struct ext4_xattr_ibody_header *header;
2174 struct ext4_inode *raw_inode;
2175 int error;
2176
2177 if (EXT4_I(inode)->i_extra_isize == 0)
2178 return 0;
2179 raw_inode = ext4_raw_inode(&is->iloc);
2180 header = IHDR(inode, raw_inode);
2181 is->s.base = is->s.first = IFIRST(header);
2182 is->s.here = is->s.first;
2183 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2184 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2185 error = xattr_check_inode(inode, header, is->s.end);
2186 if (error)
2187 return error;
2188 /* Find the named attribute. */
2189 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2190 i->name_index, i->name, 0);
2191 if (error && error != -ENODATA)
2192 return error;
2193 is->s.not_found = error;
2194 }
2195 return 0;
2196}
2197
2198int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
2199 struct ext4_xattr_info *i,
2200 struct ext4_xattr_ibody_find *is)
2201{
2202 struct ext4_xattr_ibody_header *header;
2203 struct ext4_xattr_search *s = &is->s;
2204 int error;
2205
2206 if (EXT4_I(inode)->i_extra_isize == 0)
2207 return -ENOSPC;
2208 error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2209 if (error) {
2210 if (error == -ENOSPC &&
2211 ext4_has_inline_data(inode)) {
2212 error = ext4_try_to_evict_inline_data(handle, inode,
2213 EXT4_XATTR_LEN(strlen(i->name) +
2214 EXT4_XATTR_SIZE(i->value_len)));
2215 if (error)
2216 return error;
2217 error = ext4_xattr_ibody_find(inode, i, is);
2218 if (error)
2219 return error;
2220 error = ext4_xattr_set_entry(i, s, handle, inode,
2221 false /* is_block */);
2222 }
2223 if (error)
2224 return error;
2225 }
2226 header = IHDR(inode, ext4_raw_inode(&is->iloc));
2227 if (!IS_LAST_ENTRY(s->first)) {
2228 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2229 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2230 } else {
2231 header->h_magic = cpu_to_le32(0);
2232 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2233 }
2234 return 0;
2235}
2236
2237static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2238 struct ext4_xattr_info *i,
2239 struct ext4_xattr_ibody_find *is)
2240{
2241 struct ext4_xattr_ibody_header *header;
2242 struct ext4_xattr_search *s = &is->s;
2243 int error;
2244
2245 if (EXT4_I(inode)->i_extra_isize == 0)
2246 return -ENOSPC;
2247 error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2248 if (error)
2249 return error;
2250 header = IHDR(inode, ext4_raw_inode(&is->iloc));
2251 if (!IS_LAST_ENTRY(s->first)) {
2252 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2253 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2254 } else {
2255 header->h_magic = cpu_to_le32(0);
2256 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2257 }
2258 return 0;
2259}
2260
2261static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2262 struct ext4_xattr_info *i)
2263{
2264 void *value;
2265
2266 /* When e_value_inum is set the value is stored externally. */
2267 if (s->here->e_value_inum)
2268 return 0;
2269 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2270 return 0;
2271 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2272 return !memcmp(value, i->value, i->value_len);
2273}
2274
2275static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2276{
2277 struct buffer_head *bh;
2278 int error;
2279
2280 if (!EXT4_I(inode)->i_file_acl)
2281 return NULL;
2282 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2283 if (!bh)
2284 return ERR_PTR(-EIO);
2285 error = ext4_xattr_check_block(inode, bh);
2286 if (error)
2287 return ERR_PTR(error);
2288 return bh;
2289}
2290
2291/*
2292 * ext4_xattr_set_handle()
2293 *
2294 * Create, replace or remove an extended attribute for this inode. Value
2295 * is NULL to remove an existing extended attribute, and non-NULL to
2296 * either replace an existing extended attribute, or create a new extended
2297 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2298 * specify that an extended attribute must exist and must not exist
2299 * previous to the call, respectively.
2300 *
2301 * Returns 0, or a negative error number on failure.
2302 */
2303int
2304ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2305 const char *name, const void *value, size_t value_len,
2306 int flags)
2307{
2308 struct ext4_xattr_info i = {
2309 .name_index = name_index,
2310 .name = name,
2311 .value = value,
2312 .value_len = value_len,
2313 .in_inode = 0,
2314 };
2315 struct ext4_xattr_ibody_find is = {
2316 .s = { .not_found = -ENODATA, },
2317 };
2318 struct ext4_xattr_block_find bs = {
2319 .s = { .not_found = -ENODATA, },
2320 };
2321 int no_expand;
2322 int error;
2323
2324 if (!name)
2325 return -EINVAL;
2326 if (strlen(name) > 255)
2327 return -ERANGE;
2328
2329 ext4_write_lock_xattr(inode, &no_expand);
2330
2331 /* Check journal credits under write lock. */
2332 if (ext4_handle_valid(handle)) {
2333 struct buffer_head *bh;
2334 int credits;
2335
2336 bh = ext4_xattr_get_block(inode);
2337 if (IS_ERR(bh)) {
2338 error = PTR_ERR(bh);
2339 goto cleanup;
2340 }
2341
2342 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2343 value_len,
2344 flags & XATTR_CREATE);
2345 brelse(bh);
2346
2347 if (!ext4_handle_has_enough_credits(handle, credits)) {
2348 error = -ENOSPC;
2349 goto cleanup;
2350 }
2351 }
2352
2353 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2354 if (error)
2355 goto cleanup;
2356
2357 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2358 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2359 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2360 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2361 }
2362
2363 error = ext4_xattr_ibody_find(inode, &i, &is);
2364 if (error)
2365 goto cleanup;
2366 if (is.s.not_found)
2367 error = ext4_xattr_block_find(inode, &i, &bs);
2368 if (error)
2369 goto cleanup;
2370 if (is.s.not_found && bs.s.not_found) {
2371 error = -ENODATA;
2372 if (flags & XATTR_REPLACE)
2373 goto cleanup;
2374 error = 0;
2375 if (!value)
2376 goto cleanup;
2377 } else {
2378 error = -EEXIST;
2379 if (flags & XATTR_CREATE)
2380 goto cleanup;
2381 }
2382
2383 if (!value) {
2384 if (!is.s.not_found)
2385 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2386 else if (!bs.s.not_found)
2387 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2388 } else {
2389 error = 0;
2390 /* Xattr value did not change? Save us some work and bail out */
2391 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2392 goto cleanup;
2393 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2394 goto cleanup;
2395
2396 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2397 (EXT4_XATTR_SIZE(i.value_len) >
2398 EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2399 i.in_inode = 1;
2400retry_inode:
2401 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2402 if (!error && !bs.s.not_found) {
2403 i.value = NULL;
2404 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2405 } else if (error == -ENOSPC) {
2406 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2407 error = ext4_xattr_block_find(inode, &i, &bs);
2408 if (error)
2409 goto cleanup;
2410 }
2411 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2412 if (!error && !is.s.not_found) {
2413 i.value = NULL;
2414 error = ext4_xattr_ibody_set(handle, inode, &i,
2415 &is);
2416 } else if (error == -ENOSPC) {
2417 /*
2418 * Xattr does not fit in the block, store at
2419 * external inode if possible.
2420 */
2421 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2422 !i.in_inode) {
2423 i.in_inode = 1;
2424 goto retry_inode;
2425 }
2426 }
2427 }
2428 }
2429 if (!error) {
2430 ext4_xattr_update_super_block(handle, inode->i_sb);
2431 inode->i_ctime = current_time(inode);
2432 if (!value)
2433 no_expand = 0;
2434 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2435 /*
2436 * The bh is consumed by ext4_mark_iloc_dirty, even with
2437 * error != 0.
2438 */
2439 is.iloc.bh = NULL;
2440 if (IS_SYNC(inode))
2441 ext4_handle_sync(handle);
2442 }
2443
2444cleanup:
2445 brelse(is.iloc.bh);
2446 brelse(bs.bh);
2447 ext4_write_unlock_xattr(inode, &no_expand);
2448 return error;
2449}
2450
2451int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2452 bool is_create, int *credits)
2453{
2454 struct buffer_head *bh;
2455 int err;
2456
2457 *credits = 0;
2458
2459 if (!EXT4_SB(inode->i_sb)->s_journal)
2460 return 0;
2461
2462 down_read(&EXT4_I(inode)->xattr_sem);
2463
2464 bh = ext4_xattr_get_block(inode);
2465 if (IS_ERR(bh)) {
2466 err = PTR_ERR(bh);
2467 } else {
2468 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2469 value_len, is_create);
2470 brelse(bh);
2471 err = 0;
2472 }
2473
2474 up_read(&EXT4_I(inode)->xattr_sem);
2475 return err;
2476}
2477
2478/*
2479 * ext4_xattr_set()
2480 *
2481 * Like ext4_xattr_set_handle, but start from an inode. This extended
2482 * attribute modification is a filesystem transaction by itself.
2483 *
2484 * Returns 0, or a negative error number on failure.
2485 */
2486int
2487ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2488 const void *value, size_t value_len, int flags)
2489{
2490 handle_t *handle;
2491 struct super_block *sb = inode->i_sb;
2492 int error, retries = 0;
2493 int credits;
2494
2495 error = dquot_initialize(inode);
2496 if (error)
2497 return error;
2498
2499retry:
2500 error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2501 &credits);
2502 if (error)
2503 return error;
2504
2505 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2506 if (IS_ERR(handle)) {
2507 error = PTR_ERR(handle);
2508 } else {
2509 int error2;
2510
2511 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2512 value, value_len, flags);
2513 error2 = ext4_journal_stop(handle);
2514 if (error == -ENOSPC &&
2515 ext4_should_retry_alloc(sb, &retries))
2516 goto retry;
2517 if (error == 0)
2518 error = error2;
2519 }
2520
2521 return error;
2522}
2523
2524/*
2525 * Shift the EA entries in the inode to create space for the increased
2526 * i_extra_isize.
2527 */
2528static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2529 int value_offs_shift, void *to,
2530 void *from, size_t n)
2531{
2532 struct ext4_xattr_entry *last = entry;
2533 int new_offs;
2534
2535 /* We always shift xattr headers further thus offsets get lower */
2536 BUG_ON(value_offs_shift > 0);
2537
2538 /* Adjust the value offsets of the entries */
2539 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2540 if (!last->e_value_inum && last->e_value_size) {
2541 new_offs = le16_to_cpu(last->e_value_offs) +
2542 value_offs_shift;
2543 last->e_value_offs = cpu_to_le16(new_offs);
2544 }
2545 }
2546 /* Shift the entries by n bytes */
2547 memmove(to, from, n);
2548}
2549
2550/*
2551 * Move xattr pointed to by 'entry' from inode into external xattr block
2552 */
2553static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2554 struct ext4_inode *raw_inode,
2555 struct ext4_xattr_entry *entry)
2556{
2557 struct ext4_xattr_ibody_find *is = NULL;
2558 struct ext4_xattr_block_find *bs = NULL;
2559 char *buffer = NULL, *b_entry_name = NULL;
2560 size_t value_size = le32_to_cpu(entry->e_value_size);
2561 struct ext4_xattr_info i = {
2562 .value = NULL,
2563 .value_len = 0,
2564 .name_index = entry->e_name_index,
2565 .in_inode = !!entry->e_value_inum,
2566 };
2567 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2568 int error;
2569
2570 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2571 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2572 buffer = kmalloc(value_size, GFP_NOFS);
2573 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2574 if (!is || !bs || !buffer || !b_entry_name) {
2575 error = -ENOMEM;
2576 goto out;
2577 }
2578
2579 is->s.not_found = -ENODATA;
2580 bs->s.not_found = -ENODATA;
2581 is->iloc.bh = NULL;
2582 bs->bh = NULL;
2583
2584 /* Save the entry name and the entry value */
2585 if (entry->e_value_inum) {
2586 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2587 if (error)
2588 goto out;
2589 } else {
2590 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2591 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2592 }
2593
2594 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2595 b_entry_name[entry->e_name_len] = '\0';
2596 i.name = b_entry_name;
2597
2598 error = ext4_get_inode_loc(inode, &is->iloc);
2599 if (error)
2600 goto out;
2601
2602 error = ext4_xattr_ibody_find(inode, &i, is);
2603 if (error)
2604 goto out;
2605
2606 /* Remove the chosen entry from the inode */
2607 error = ext4_xattr_ibody_set(handle, inode, &i, is);
2608 if (error)
2609 goto out;
2610
2611 i.value = buffer;
2612 i.value_len = value_size;
2613 error = ext4_xattr_block_find(inode, &i, bs);
2614 if (error)
2615 goto out;
2616
2617 /* Add entry which was removed from the inode into the block */
2618 error = ext4_xattr_block_set(handle, inode, &i, bs);
2619 if (error)
2620 goto out;
2621 error = 0;
2622out:
2623 kfree(b_entry_name);
2624 kfree(buffer);
2625 if (is)
2626 brelse(is->iloc.bh);
2627 kfree(is);
2628 kfree(bs);
2629
2630 return error;
2631}
2632
2633static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2634 struct ext4_inode *raw_inode,
2635 int isize_diff, size_t ifree,
2636 size_t bfree, int *total_ino)
2637{
2638 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2639 struct ext4_xattr_entry *small_entry;
2640 struct ext4_xattr_entry *entry;
2641 struct ext4_xattr_entry *last;
2642 unsigned int entry_size; /* EA entry size */
2643 unsigned int total_size; /* EA entry size + value size */
2644 unsigned int min_total_size;
2645 int error;
2646
2647 while (isize_diff > ifree) {
2648 entry = NULL;
2649 small_entry = NULL;
2650 min_total_size = ~0U;
2651 last = IFIRST(header);
2652 /* Find the entry best suited to be pushed into EA block */
2653 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2654 total_size = EXT4_XATTR_LEN(last->e_name_len);
2655 if (!last->e_value_inum)
2656 total_size += EXT4_XATTR_SIZE(
2657 le32_to_cpu(last->e_value_size));
2658 if (total_size <= bfree &&
2659 total_size < min_total_size) {
2660 if (total_size + ifree < isize_diff) {
2661 small_entry = last;
2662 } else {
2663 entry = last;
2664 min_total_size = total_size;
2665 }
2666 }
2667 }
2668
2669 if (entry == NULL) {
2670 if (small_entry == NULL)
2671 return -ENOSPC;
2672 entry = small_entry;
2673 }
2674
2675 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2676 total_size = entry_size;
2677 if (!entry->e_value_inum)
2678 total_size += EXT4_XATTR_SIZE(
2679 le32_to_cpu(entry->e_value_size));
2680 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2681 entry);
2682 if (error)
2683 return error;
2684
2685 *total_ino -= entry_size;
2686 ifree += total_size;
2687 bfree -= total_size;
2688 }
2689
2690 return 0;
2691}
2692
2693/*
2694 * Expand an inode by new_extra_isize bytes when EAs are present.
2695 * Returns 0 on success or negative error number on failure.
2696 */
2697int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2698 struct ext4_inode *raw_inode, handle_t *handle)
2699{
2700 struct ext4_xattr_ibody_header *header;
2701 struct buffer_head *bh;
2702 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2703 static unsigned int mnt_count;
2704 size_t min_offs;
2705 size_t ifree, bfree;
2706 int total_ino;
2707 void *base, *end;
2708 int error = 0, tried_min_extra_isize = 0;
2709 int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2710 int isize_diff; /* How much do we need to grow i_extra_isize */
2711
2712retry:
2713 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2714 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2715 return 0;
2716
2717 header = IHDR(inode, raw_inode);
2718
2719 /*
2720 * Check if enough free space is available in the inode to shift the
2721 * entries ahead by new_extra_isize.
2722 */
2723
2724 base = IFIRST(header);
2725 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2726 min_offs = end - base;
2727 total_ino = sizeof(struct ext4_xattr_ibody_header);
2728
2729 error = xattr_check_inode(inode, header, end);
2730 if (error)
2731 goto cleanup;
2732
2733 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2734 if (ifree >= isize_diff)
2735 goto shift;
2736
2737 /*
2738 * Enough free space isn't available in the inode, check if
2739 * EA block can hold new_extra_isize bytes.
2740 */
2741 if (EXT4_I(inode)->i_file_acl) {
2742 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2743 error = -EIO;
2744 if (!bh)
2745 goto cleanup;
2746 error = ext4_xattr_check_block(inode, bh);
2747 if (error)
2748 goto cleanup;
2749 base = BHDR(bh);
2750 end = bh->b_data + bh->b_size;
2751 min_offs = end - base;
2752 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2753 NULL);
2754 brelse(bh);
2755 if (bfree + ifree < isize_diff) {
2756 if (!tried_min_extra_isize && s_min_extra_isize) {
2757 tried_min_extra_isize++;
2758 new_extra_isize = s_min_extra_isize;
2759 goto retry;
2760 }
2761 error = -ENOSPC;
2762 goto cleanup;
2763 }
2764 } else {
2765 bfree = inode->i_sb->s_blocksize;
2766 }
2767
2768 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2769 isize_diff, ifree, bfree,
2770 &total_ino);
2771 if (error) {
2772 if (error == -ENOSPC && !tried_min_extra_isize &&
2773 s_min_extra_isize) {
2774 tried_min_extra_isize++;
2775 new_extra_isize = s_min_extra_isize;
2776 goto retry;
2777 }
2778 goto cleanup;
2779 }
2780shift:
2781 /* Adjust the offsets and shift the remaining entries ahead */
2782 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2783 - new_extra_isize, (void *)raw_inode +
2784 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2785 (void *)header, total_ino);
2786 EXT4_I(inode)->i_extra_isize = new_extra_isize;
2787
2788cleanup:
2789 if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2790 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2791 inode->i_ino);
2792 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2793 }
2794 return error;
2795}
2796
2797#define EIA_INCR 16 /* must be 2^n */
2798#define EIA_MASK (EIA_INCR - 1)
2799
2800/* Add the large xattr @inode into @ea_inode_array for deferred iput().
2801 * If @ea_inode_array is new or full it will be grown and the old
2802 * contents copied over.
2803 */
2804static int
2805ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2806 struct inode *inode)
2807{
2808 if (*ea_inode_array == NULL) {
2809 /*
2810 * Start with 15 inodes, so it fits into a power-of-two size.
2811 * If *ea_inode_array is NULL, this is essentially offsetof()
2812 */
2813 (*ea_inode_array) =
2814 kmalloc(offsetof(struct ext4_xattr_inode_array,
2815 inodes[EIA_MASK]),
2816 GFP_NOFS);
2817 if (*ea_inode_array == NULL)
2818 return -ENOMEM;
2819 (*ea_inode_array)->count = 0;
2820 } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2821 /* expand the array once all 15 + n * 16 slots are full */
2822 struct ext4_xattr_inode_array *new_array = NULL;
2823 int count = (*ea_inode_array)->count;
2824
2825 /* if new_array is NULL, this is essentially offsetof() */
2826 new_array = kmalloc(
2827 offsetof(struct ext4_xattr_inode_array,
2828 inodes[count + EIA_INCR]),
2829 GFP_NOFS);
2830 if (new_array == NULL)
2831 return -ENOMEM;
2832 memcpy(new_array, *ea_inode_array,
2833 offsetof(struct ext4_xattr_inode_array, inodes[count]));
2834 kfree(*ea_inode_array);
2835 *ea_inode_array = new_array;
2836 }
2837 (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2838 return 0;
2839}
2840
2841/*
2842 * ext4_xattr_delete_inode()
2843 *
2844 * Free extended attribute resources associated with this inode. Traverse
2845 * all entries and decrement reference on any xattr inodes associated with this
2846 * inode. This is called immediately before an inode is freed. We have exclusive
2847 * access to the inode. If an orphan inode is deleted it will also release its
2848 * references on xattr block and xattr inodes.
2849 */
2850int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2851 struct ext4_xattr_inode_array **ea_inode_array,
2852 int extra_credits)
2853{
2854 struct buffer_head *bh = NULL;
2855 struct ext4_xattr_ibody_header *header;
2856 struct ext4_iloc iloc = { .bh = NULL };
2857 struct ext4_xattr_entry *entry;
2858 struct inode *ea_inode;
2859 int error;
2860
2861 error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
2862 NULL /* bh */,
2863 false /* dirty */,
2864 false /* block_csum */);
2865 if (error) {
2866 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2867 goto cleanup;
2868 }
2869
2870 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2871 ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2872
2873 error = ext4_get_inode_loc(inode, &iloc);
2874 if (error) {
2875 EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2876 goto cleanup;
2877 }
2878
2879 error = ext4_journal_get_write_access(handle, iloc.bh);
2880 if (error) {
2881 EXT4_ERROR_INODE(inode, "write access (error %d)",
2882 error);
2883 goto cleanup;
2884 }
2885
2886 header = IHDR(inode, ext4_raw_inode(&iloc));
2887 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2888 ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2889 IFIRST(header),
2890 false /* block_csum */,
2891 ea_inode_array,
2892 extra_credits,
2893 false /* skip_quota */);
2894 }
2895
2896 if (EXT4_I(inode)->i_file_acl) {
2897 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
2898 if (!bh) {
2899 EXT4_ERROR_INODE(inode, "block %llu read error",
2900 EXT4_I(inode)->i_file_acl);
2901 error = -EIO;
2902 goto cleanup;
2903 }
2904 error = ext4_xattr_check_block(inode, bh);
2905 if (error)
2906 goto cleanup;
2907
2908 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2909 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2910 entry = EXT4_XATTR_NEXT(entry)) {
2911 if (!entry->e_value_inum)
2912 continue;
2913 error = ext4_xattr_inode_iget(inode,
2914 le32_to_cpu(entry->e_value_inum),
2915 le32_to_cpu(entry->e_hash),
2916 &ea_inode);
2917 if (error)
2918 continue;
2919 ext4_xattr_inode_free_quota(inode, ea_inode,
2920 le32_to_cpu(entry->e_value_size));
2921 iput(ea_inode);
2922 }
2923
2924 }
2925
2926 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2927 extra_credits);
2928 /*
2929 * Update i_file_acl value in the same transaction that releases
2930 * block.
2931 */
2932 EXT4_I(inode)->i_file_acl = 0;
2933 error = ext4_mark_inode_dirty(handle, inode);
2934 if (error) {
2935 EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2936 error);
2937 goto cleanup;
2938 }
2939 }
2940 error = 0;
2941cleanup:
2942 brelse(iloc.bh);
2943 brelse(bh);
2944 return error;
2945}
2946
2947void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2948{
2949 int idx;
2950
2951 if (ea_inode_array == NULL)
2952 return;
2953
2954 for (idx = 0; idx < ea_inode_array->count; ++idx)
2955 iput(ea_inode_array->inodes[idx]);
2956 kfree(ea_inode_array);
2957}
2958
2959/*
2960 * ext4_xattr_block_cache_insert()
2961 *
2962 * Create a new entry in the extended attribute block cache, and insert
2963 * it unless such an entry is already in the cache.
2964 *
2965 * Returns 0, or a negative error number on failure.
2966 */
2967static void
2968ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2969 struct buffer_head *bh)
2970{
2971 struct ext4_xattr_header *header = BHDR(bh);
2972 __u32 hash = le32_to_cpu(header->h_hash);
2973 int reusable = le32_to_cpu(header->h_refcount) <
2974 EXT4_XATTR_REFCOUNT_MAX;
2975 int error;
2976
2977 if (!ea_block_cache)
2978 return;
2979 error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2980 bh->b_blocknr, reusable);
2981 if (error) {
2982 if (error == -EBUSY)
2983 ea_bdebug(bh, "already in cache");
2984 } else
2985 ea_bdebug(bh, "inserting [%x]", (int)hash);
2986}
2987
2988/*
2989 * ext4_xattr_cmp()
2990 *
2991 * Compare two extended attribute blocks for equality.
2992 *
2993 * Returns 0 if the blocks are equal, 1 if they differ, and
2994 * a negative error number on errors.
2995 */
2996static int
2997ext4_xattr_cmp(struct ext4_xattr_header *header1,
2998 struct ext4_xattr_header *header2)
2999{
3000 struct ext4_xattr_entry *entry1, *entry2;
3001
3002 entry1 = ENTRY(header1+1);
3003 entry2 = ENTRY(header2+1);
3004 while (!IS_LAST_ENTRY(entry1)) {
3005 if (IS_LAST_ENTRY(entry2))
3006 return 1;
3007 if (entry1->e_hash != entry2->e_hash ||
3008 entry1->e_name_index != entry2->e_name_index ||
3009 entry1->e_name_len != entry2->e_name_len ||
3010 entry1->e_value_size != entry2->e_value_size ||
3011 entry1->e_value_inum != entry2->e_value_inum ||
3012 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3013 return 1;
3014 if (!entry1->e_value_inum &&
3015 memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3016 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3017 le32_to_cpu(entry1->e_value_size)))
3018 return 1;
3019
3020 entry1 = EXT4_XATTR_NEXT(entry1);
3021 entry2 = EXT4_XATTR_NEXT(entry2);
3022 }
3023 if (!IS_LAST_ENTRY(entry2))
3024 return 1;
3025 return 0;
3026}
3027
3028/*
3029 * ext4_xattr_block_cache_find()
3030 *
3031 * Find an identical extended attribute block.
3032 *
3033 * Returns a pointer to the block found, or NULL if such a block was
3034 * not found or an error occurred.
3035 */
3036static struct buffer_head *
3037ext4_xattr_block_cache_find(struct inode *inode,
3038 struct ext4_xattr_header *header,
3039 struct mb_cache_entry **pce)
3040{
3041 __u32 hash = le32_to_cpu(header->h_hash);
3042 struct mb_cache_entry *ce;
3043 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3044
3045 if (!ea_block_cache)
3046 return NULL;
3047 if (!header->h_hash)
3048 return NULL; /* never share */
3049 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3050 ce = mb_cache_entry_find_first(ea_block_cache, hash);
3051 while (ce) {
3052 struct buffer_head *bh;
3053
3054 bh = sb_bread(inode->i_sb, ce->e_value);
3055 if (!bh) {
3056 EXT4_ERROR_INODE(inode, "block %lu read error",
3057 (unsigned long)ce->e_value);
3058 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3059 *pce = ce;
3060 return bh;
3061 }
3062 brelse(bh);
3063 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3064 }
3065 return NULL;
3066}
3067
3068#define NAME_HASH_SHIFT 5
3069#define VALUE_HASH_SHIFT 16
3070
3071/*
3072 * ext4_xattr_hash_entry()
3073 *
3074 * Compute the hash of an extended attribute.
3075 */
3076static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3077 size_t value_count)
3078{
3079 __u32 hash = 0;
3080
3081 while (name_len--) {
3082 hash = (hash << NAME_HASH_SHIFT) ^
3083 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3084 *name++;
3085 }
3086 while (value_count--) {
3087 hash = (hash << VALUE_HASH_SHIFT) ^
3088 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3089 le32_to_cpu(*value++);
3090 }
3091 return cpu_to_le32(hash);
3092}
3093
3094#undef NAME_HASH_SHIFT
3095#undef VALUE_HASH_SHIFT
3096
3097#define BLOCK_HASH_SHIFT 16
3098
3099/*
3100 * ext4_xattr_rehash()
3101 *
3102 * Re-compute the extended attribute hash value after an entry has changed.
3103 */
3104static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3105{
3106 struct ext4_xattr_entry *here;
3107 __u32 hash = 0;
3108
3109 here = ENTRY(header+1);
3110 while (!IS_LAST_ENTRY(here)) {
3111 if (!here->e_hash) {
3112 /* Block is not shared if an entry's hash value == 0 */
3113 hash = 0;
3114 break;
3115 }
3116 hash = (hash << BLOCK_HASH_SHIFT) ^
3117 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3118 le32_to_cpu(here->e_hash);
3119 here = EXT4_XATTR_NEXT(here);
3120 }
3121 header->h_hash = cpu_to_le32(hash);
3122}
3123
3124#undef BLOCK_HASH_SHIFT
3125
3126#define HASH_BUCKET_BITS 10
3127
3128struct mb_cache *
3129ext4_xattr_create_cache(void)
3130{
3131 return mb_cache_create(HASH_BUCKET_BITS);
3132}
3133
3134void ext4_xattr_destroy_cache(struct mb_cache *cache)
3135{
3136 if (cache)
3137 mb_cache_destroy(cache);
3138}
3139