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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 [EXT4_XATTR_INDEX_HURD] = &ext4_xattr_hurd_handler,
97};
98
99const struct xattr_handler *ext4_xattr_handlers[] = {
100 &ext4_xattr_user_handler,
101 &ext4_xattr_trusted_handler,
102#ifdef CONFIG_EXT4_FS_POSIX_ACL
103 &posix_acl_access_xattr_handler,
104 &posix_acl_default_xattr_handler,
105#endif
106#ifdef CONFIG_EXT4_FS_SECURITY
107 &ext4_xattr_security_handler,
108#endif
109 &ext4_xattr_hurd_handler,
110 NULL
111};
112
113#define EA_BLOCK_CACHE(inode) (((struct ext4_sb_info *) \
114 inode->i_sb->s_fs_info)->s_ea_block_cache)
115
116#define EA_INODE_CACHE(inode) (((struct ext4_sb_info *) \
117 inode->i_sb->s_fs_info)->s_ea_inode_cache)
118
119static int
120ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
121 struct inode *inode);
122
123#ifdef CONFIG_LOCKDEP
124void ext4_xattr_inode_set_class(struct inode *ea_inode)
125{
126 lockdep_set_subclass(&ea_inode->i_rwsem, 1);
127}
128#endif
129
130static __le32 ext4_xattr_block_csum(struct inode *inode,
131 sector_t block_nr,
132 struct ext4_xattr_header *hdr)
133{
134 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
135 __u32 csum;
136 __le64 dsk_block_nr = cpu_to_le64(block_nr);
137 __u32 dummy_csum = 0;
138 int offset = offsetof(struct ext4_xattr_header, h_checksum);
139
140 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
141 sizeof(dsk_block_nr));
142 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
143 csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
144 offset += sizeof(dummy_csum);
145 csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
146 EXT4_BLOCK_SIZE(inode->i_sb) - offset);
147
148 return cpu_to_le32(csum);
149}
150
151static int ext4_xattr_block_csum_verify(struct inode *inode,
152 struct buffer_head *bh)
153{
154 struct ext4_xattr_header *hdr = BHDR(bh);
155 int ret = 1;
156
157 if (ext4_has_metadata_csum(inode->i_sb)) {
158 lock_buffer(bh);
159 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
160 bh->b_blocknr, hdr));
161 unlock_buffer(bh);
162 }
163 return ret;
164}
165
166static void ext4_xattr_block_csum_set(struct inode *inode,
167 struct buffer_head *bh)
168{
169 if (ext4_has_metadata_csum(inode->i_sb))
170 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
171 bh->b_blocknr, BHDR(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
184static int
185ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
186 void *value_start)
187{
188 struct ext4_xattr_entry *e = entry;
189
190 /* Find the end of the names list */
191 while (!IS_LAST_ENTRY(e)) {
192 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
193 if ((void *)next >= end)
194 return -EFSCORRUPTED;
195 if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
196 return -EFSCORRUPTED;
197 e = next;
198 }
199
200 /* Check the values */
201 while (!IS_LAST_ENTRY(entry)) {
202 u32 size = le32_to_cpu(entry->e_value_size);
203
204 if (size > EXT4_XATTR_SIZE_MAX)
205 return -EFSCORRUPTED;
206
207 if (size != 0 && entry->e_value_inum == 0) {
208 u16 offs = le16_to_cpu(entry->e_value_offs);
209 void *value;
210
211 /*
212 * The value cannot overlap the names, and the value
213 * with padding cannot extend beyond 'end'. Check both
214 * the padded and unpadded sizes, since the size may
215 * overflow to 0 when adding padding.
216 */
217 if (offs > end - value_start)
218 return -EFSCORRUPTED;
219 value = value_start + offs;
220 if (value < (void *)e + sizeof(u32) ||
221 size > end - value ||
222 EXT4_XATTR_SIZE(size) > end - value)
223 return -EFSCORRUPTED;
224 }
225 entry = EXT4_XATTR_NEXT(entry);
226 }
227
228 return 0;
229}
230
231static inline int
232__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
233 const char *function, unsigned int line)
234{
235 int error = -EFSCORRUPTED;
236
237 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
238 BHDR(bh)->h_blocks != cpu_to_le32(1))
239 goto errout;
240 if (buffer_verified(bh))
241 return 0;
242
243 error = -EFSBADCRC;
244 if (!ext4_xattr_block_csum_verify(inode, bh))
245 goto errout;
246 error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
247 bh->b_data);
248errout:
249 if (error)
250 __ext4_error_inode(inode, function, line, 0, -error,
251 "corrupted xattr block %llu",
252 (unsigned long long) bh->b_blocknr);
253 else
254 set_buffer_verified(bh);
255 return error;
256}
257
258#define ext4_xattr_check_block(inode, bh) \
259 __ext4_xattr_check_block((inode), (bh), __func__, __LINE__)
260
261
262static int
263__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
264 void *end, const char *function, unsigned int line)
265{
266 int error = -EFSCORRUPTED;
267
268 if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
269 (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
270 goto errout;
271 error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
272errout:
273 if (error)
274 __ext4_error_inode(inode, function, line, 0, -error,
275 "corrupted in-inode xattr");
276 return error;
277}
278
279#define xattr_check_inode(inode, header, end) \
280 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
281
282static int
283xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
284 void *end, int name_index, const char *name, int sorted)
285{
286 struct ext4_xattr_entry *entry, *next;
287 size_t name_len;
288 int cmp = 1;
289
290 if (name == NULL)
291 return -EINVAL;
292 name_len = strlen(name);
293 for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
294 next = EXT4_XATTR_NEXT(entry);
295 if ((void *) next >= end) {
296 EXT4_ERROR_INODE(inode, "corrupted xattr entries");
297 return -EFSCORRUPTED;
298 }
299 cmp = name_index - entry->e_name_index;
300 if (!cmp)
301 cmp = name_len - entry->e_name_len;
302 if (!cmp)
303 cmp = memcmp(name, entry->e_name, name_len);
304 if (cmp <= 0 && (sorted || cmp == 0))
305 break;
306 }
307 *pentry = entry;
308 return cmp ? -ENODATA : 0;
309}
310
311static u32
312ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
313{
314 return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
315}
316
317static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
318{
319 return ((u64)ea_inode->i_ctime.tv_sec << 32) |
320 (u32) inode_peek_iversion_raw(ea_inode);
321}
322
323static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
324{
325 ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
326 inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
327}
328
329static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
330{
331 return (u32)ea_inode->i_atime.tv_sec;
332}
333
334static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
335{
336 ea_inode->i_atime.tv_sec = hash;
337}
338
339/*
340 * Read the EA value from an inode.
341 */
342static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
343{
344 int blocksize = 1 << ea_inode->i_blkbits;
345 int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
346 int tail_size = (size % blocksize) ?: blocksize;
347 struct buffer_head *bhs_inline[8];
348 struct buffer_head **bhs = bhs_inline;
349 int i, ret;
350
351 if (bh_count > ARRAY_SIZE(bhs_inline)) {
352 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
353 if (!bhs)
354 return -ENOMEM;
355 }
356
357 ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
358 true /* wait */, bhs);
359 if (ret)
360 goto free_bhs;
361
362 for (i = 0; i < bh_count; i++) {
363 /* There shouldn't be any holes in ea_inode. */
364 if (!bhs[i]) {
365 ret = -EFSCORRUPTED;
366 goto put_bhs;
367 }
368 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
369 i < bh_count - 1 ? blocksize : tail_size);
370 }
371 ret = 0;
372put_bhs:
373 for (i = 0; i < bh_count; i++)
374 brelse(bhs[i]);
375free_bhs:
376 if (bhs != bhs_inline)
377 kfree(bhs);
378 return ret;
379}
380
381#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
382
383static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
384 u32 ea_inode_hash, struct inode **ea_inode)
385{
386 struct inode *inode;
387 int err;
388
389 inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
390 if (IS_ERR(inode)) {
391 err = PTR_ERR(inode);
392 ext4_error(parent->i_sb,
393 "error while reading EA inode %lu err=%d", ea_ino,
394 err);
395 return err;
396 }
397
398 if (is_bad_inode(inode)) {
399 ext4_error(parent->i_sb,
400 "error while reading EA inode %lu is_bad_inode",
401 ea_ino);
402 err = -EIO;
403 goto error;
404 }
405
406 if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
407 ext4_error(parent->i_sb,
408 "EA inode %lu does not have EXT4_EA_INODE_FL flag",
409 ea_ino);
410 err = -EINVAL;
411 goto error;
412 }
413
414 ext4_xattr_inode_set_class(inode);
415
416 /*
417 * Check whether this is an old Lustre-style xattr inode. Lustre
418 * implementation does not have hash validation, rather it has a
419 * backpointer from ea_inode to the parent inode.
420 */
421 if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
422 EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
423 inode->i_generation == parent->i_generation) {
424 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
425 ext4_xattr_inode_set_ref(inode, 1);
426 } else {
427 inode_lock(inode);
428 inode->i_flags |= S_NOQUOTA;
429 inode_unlock(inode);
430 }
431
432 *ea_inode = inode;
433 return 0;
434error:
435 iput(inode);
436 return err;
437}
438
439static int
440ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
441 struct ext4_xattr_entry *entry, void *buffer,
442 size_t size)
443{
444 u32 hash;
445
446 /* Verify stored hash matches calculated hash. */
447 hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
448 if (hash != ext4_xattr_inode_get_hash(ea_inode))
449 return -EFSCORRUPTED;
450
451 if (entry) {
452 __le32 e_hash, tmp_data;
453
454 /* Verify entry hash. */
455 tmp_data = cpu_to_le32(hash);
456 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
457 &tmp_data, 1);
458 if (e_hash != entry->e_hash)
459 return -EFSCORRUPTED;
460 }
461 return 0;
462}
463
464/*
465 * Read xattr value from the EA inode.
466 */
467static int
468ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
469 void *buffer, size_t size)
470{
471 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
472 struct inode *ea_inode;
473 int err;
474
475 err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
476 le32_to_cpu(entry->e_hash), &ea_inode);
477 if (err) {
478 ea_inode = NULL;
479 goto out;
480 }
481
482 if (i_size_read(ea_inode) != size) {
483 ext4_warning_inode(ea_inode,
484 "ea_inode file size=%llu entry size=%zu",
485 i_size_read(ea_inode), size);
486 err = -EFSCORRUPTED;
487 goto out;
488 }
489
490 err = ext4_xattr_inode_read(ea_inode, buffer, size);
491 if (err)
492 goto out;
493
494 if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
495 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
496 size);
497 if (err) {
498 ext4_warning_inode(ea_inode,
499 "EA inode hash validation failed");
500 goto out;
501 }
502
503 if (ea_inode_cache)
504 mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
505 ext4_xattr_inode_get_hash(ea_inode),
506 ea_inode->i_ino, true /* reusable */);
507 }
508out:
509 iput(ea_inode);
510 return err;
511}
512
513static int
514ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
515 void *buffer, size_t buffer_size)
516{
517 struct buffer_head *bh = NULL;
518 struct ext4_xattr_entry *entry;
519 size_t size;
520 void *end;
521 int error;
522 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
523
524 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
525 name_index, name, buffer, (long)buffer_size);
526
527 if (!EXT4_I(inode)->i_file_acl)
528 return -ENODATA;
529 ea_idebug(inode, "reading block %llu",
530 (unsigned long long)EXT4_I(inode)->i_file_acl);
531 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
532 if (IS_ERR(bh))
533 return PTR_ERR(bh);
534 ea_bdebug(bh, "b_count=%d, refcount=%d",
535 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
536 error = ext4_xattr_check_block(inode, bh);
537 if (error)
538 goto cleanup;
539 ext4_xattr_block_cache_insert(ea_block_cache, bh);
540 entry = BFIRST(bh);
541 end = bh->b_data + bh->b_size;
542 error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
543 if (error)
544 goto cleanup;
545 size = le32_to_cpu(entry->e_value_size);
546 error = -ERANGE;
547 if (unlikely(size > EXT4_XATTR_SIZE_MAX))
548 goto cleanup;
549 if (buffer) {
550 if (size > buffer_size)
551 goto cleanup;
552 if (entry->e_value_inum) {
553 error = ext4_xattr_inode_get(inode, entry, buffer,
554 size);
555 if (error)
556 goto cleanup;
557 } else {
558 u16 offset = le16_to_cpu(entry->e_value_offs);
559 void *p = bh->b_data + offset;
560
561 if (unlikely(p + size > end))
562 goto cleanup;
563 memcpy(buffer, p, size);
564 }
565 }
566 error = size;
567
568cleanup:
569 brelse(bh);
570 return error;
571}
572
573int
574ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
575 void *buffer, size_t buffer_size)
576{
577 struct ext4_xattr_ibody_header *header;
578 struct ext4_xattr_entry *entry;
579 struct ext4_inode *raw_inode;
580 struct ext4_iloc iloc;
581 size_t size;
582 void *end;
583 int error;
584
585 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
586 return -ENODATA;
587 error = ext4_get_inode_loc(inode, &iloc);
588 if (error)
589 return error;
590 raw_inode = ext4_raw_inode(&iloc);
591 header = IHDR(inode, raw_inode);
592 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
593 error = xattr_check_inode(inode, header, end);
594 if (error)
595 goto cleanup;
596 entry = IFIRST(header);
597 error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
598 if (error)
599 goto cleanup;
600 size = le32_to_cpu(entry->e_value_size);
601 error = -ERANGE;
602 if (unlikely(size > EXT4_XATTR_SIZE_MAX))
603 goto cleanup;
604 if (buffer) {
605 if (size > buffer_size)
606 goto cleanup;
607 if (entry->e_value_inum) {
608 error = ext4_xattr_inode_get(inode, entry, buffer,
609 size);
610 if (error)
611 goto cleanup;
612 } else {
613 u16 offset = le16_to_cpu(entry->e_value_offs);
614 void *p = (void *)IFIRST(header) + offset;
615
616 if (unlikely(p + size > end))
617 goto cleanup;
618 memcpy(buffer, p, size);
619 }
620 }
621 error = size;
622
623cleanup:
624 brelse(iloc.bh);
625 return error;
626}
627
628/*
629 * ext4_xattr_get()
630 *
631 * Copy an extended attribute into the buffer
632 * provided, or compute the buffer size required.
633 * Buffer is NULL to compute the size of the buffer required.
634 *
635 * Returns a negative error number on failure, or the number of bytes
636 * used / required on success.
637 */
638int
639ext4_xattr_get(struct inode *inode, int name_index, const char *name,
640 void *buffer, size_t buffer_size)
641{
642 int error;
643
644 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
645 return -EIO;
646
647 if (strlen(name) > 255)
648 return -ERANGE;
649
650 down_read(&EXT4_I(inode)->xattr_sem);
651 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
652 buffer_size);
653 if (error == -ENODATA)
654 error = ext4_xattr_block_get(inode, name_index, name, buffer,
655 buffer_size);
656 up_read(&EXT4_I(inode)->xattr_sem);
657 return error;
658}
659
660static int
661ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
662 char *buffer, size_t buffer_size)
663{
664 size_t rest = buffer_size;
665
666 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
667 const struct xattr_handler *handler =
668 ext4_xattr_handler(entry->e_name_index);
669
670 if (handler && (!handler->list || handler->list(dentry))) {
671 const char *prefix = handler->prefix ?: handler->name;
672 size_t prefix_len = strlen(prefix);
673 size_t size = prefix_len + entry->e_name_len + 1;
674
675 if (buffer) {
676 if (size > rest)
677 return -ERANGE;
678 memcpy(buffer, prefix, prefix_len);
679 buffer += prefix_len;
680 memcpy(buffer, entry->e_name, entry->e_name_len);
681 buffer += entry->e_name_len;
682 *buffer++ = 0;
683 }
684 rest -= size;
685 }
686 }
687 return buffer_size - rest; /* total size */
688}
689
690static int
691ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
692{
693 struct inode *inode = d_inode(dentry);
694 struct buffer_head *bh = NULL;
695 int error;
696
697 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
698 buffer, (long)buffer_size);
699
700 if (!EXT4_I(inode)->i_file_acl)
701 return 0;
702 ea_idebug(inode, "reading block %llu",
703 (unsigned long long)EXT4_I(inode)->i_file_acl);
704 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
705 if (IS_ERR(bh))
706 return PTR_ERR(bh);
707 ea_bdebug(bh, "b_count=%d, refcount=%d",
708 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
709 error = ext4_xattr_check_block(inode, bh);
710 if (error)
711 goto cleanup;
712 ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
713 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
714 buffer_size);
715cleanup:
716 brelse(bh);
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 lock_buffer(EXT4_SB(sb)->s_sbh);
796 ext4_set_feature_xattr(sb);
797 ext4_superblock_csum_set(sb);
798 unlock_buffer(EXT4_SB(sb)->s_sbh);
799 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
800 }
801}
802
803int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
804{
805 struct ext4_iloc iloc = { .bh = NULL };
806 struct buffer_head *bh = NULL;
807 struct ext4_inode *raw_inode;
808 struct ext4_xattr_ibody_header *header;
809 struct ext4_xattr_entry *entry;
810 qsize_t ea_inode_refs = 0;
811 void *end;
812 int ret;
813
814 lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
815
816 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
817 ret = ext4_get_inode_loc(inode, &iloc);
818 if (ret)
819 goto out;
820 raw_inode = ext4_raw_inode(&iloc);
821 header = IHDR(inode, raw_inode);
822 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
823 ret = xattr_check_inode(inode, header, end);
824 if (ret)
825 goto out;
826
827 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
828 entry = EXT4_XATTR_NEXT(entry))
829 if (entry->e_value_inum)
830 ea_inode_refs++;
831 }
832
833 if (EXT4_I(inode)->i_file_acl) {
834 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
835 if (IS_ERR(bh)) {
836 ret = PTR_ERR(bh);
837 bh = NULL;
838 goto out;
839 }
840
841 ret = ext4_xattr_check_block(inode, bh);
842 if (ret)
843 goto out;
844
845 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
846 entry = EXT4_XATTR_NEXT(entry))
847 if (entry->e_value_inum)
848 ea_inode_refs++;
849 }
850 *usage = ea_inode_refs + 1;
851 ret = 0;
852out:
853 brelse(iloc.bh);
854 brelse(bh);
855 return ret;
856}
857
858static inline size_t round_up_cluster(struct inode *inode, size_t length)
859{
860 struct super_block *sb = inode->i_sb;
861 size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
862 inode->i_blkbits);
863 size_t mask = ~(cluster_size - 1);
864
865 return (length + cluster_size - 1) & mask;
866}
867
868static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
869{
870 int err;
871
872 err = dquot_alloc_inode(inode);
873 if (err)
874 return err;
875 err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
876 if (err)
877 dquot_free_inode(inode);
878 return err;
879}
880
881static void ext4_xattr_inode_free_quota(struct inode *parent,
882 struct inode *ea_inode,
883 size_t len)
884{
885 if (ea_inode &&
886 ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
887 return;
888 dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
889 dquot_free_inode(parent);
890}
891
892int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
893 struct buffer_head *block_bh, size_t value_len,
894 bool is_create)
895{
896 int credits;
897 int blocks;
898
899 /*
900 * 1) Owner inode update
901 * 2) Ref count update on old xattr block
902 * 3) new xattr block
903 * 4) block bitmap update for new xattr block
904 * 5) group descriptor for new xattr block
905 * 6) block bitmap update for old xattr block
906 * 7) group descriptor for old block
907 *
908 * 6 & 7 can happen if we have two racing threads T_a and T_b
909 * which are each trying to set an xattr on inodes I_a and I_b
910 * which were both initially sharing an xattr block.
911 */
912 credits = 7;
913
914 /* Quota updates. */
915 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
916
917 /*
918 * In case of inline data, we may push out the data to a block,
919 * so we need to reserve credits for this eventuality
920 */
921 if (inode && ext4_has_inline_data(inode))
922 credits += ext4_writepage_trans_blocks(inode) + 1;
923
924 /* We are done if ea_inode feature is not enabled. */
925 if (!ext4_has_feature_ea_inode(sb))
926 return credits;
927
928 /* New ea_inode, inode map, block bitmap, group descriptor. */
929 credits += 4;
930
931 /* Data blocks. */
932 blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
933
934 /* Indirection block or one level of extent tree. */
935 blocks += 1;
936
937 /* Block bitmap and group descriptor updates for each block. */
938 credits += blocks * 2;
939
940 /* Blocks themselves. */
941 credits += blocks;
942
943 if (!is_create) {
944 /* Dereference ea_inode holding old xattr value.
945 * Old ea_inode, inode map, block bitmap, group descriptor.
946 */
947 credits += 4;
948
949 /* Data blocks for old ea_inode. */
950 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
951
952 /* Indirection block or one level of extent tree for old
953 * ea_inode.
954 */
955 blocks += 1;
956
957 /* Block bitmap and group descriptor updates for each block. */
958 credits += blocks * 2;
959 }
960
961 /* We may need to clone the existing xattr block in which case we need
962 * to increment ref counts for existing ea_inodes referenced by it.
963 */
964 if (block_bh) {
965 struct ext4_xattr_entry *entry = BFIRST(block_bh);
966
967 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
968 if (entry->e_value_inum)
969 /* Ref count update on ea_inode. */
970 credits += 1;
971 }
972 return credits;
973}
974
975static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
976 int ref_change)
977{
978 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
979 struct ext4_iloc iloc;
980 s64 ref_count;
981 u32 hash;
982 int ret;
983
984 inode_lock(ea_inode);
985
986 ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
987 if (ret)
988 goto out;
989
990 ref_count = ext4_xattr_inode_get_ref(ea_inode);
991 ref_count += ref_change;
992 ext4_xattr_inode_set_ref(ea_inode, ref_count);
993
994 if (ref_change > 0) {
995 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
996 ea_inode->i_ino, ref_count);
997
998 if (ref_count == 1) {
999 WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1000 ea_inode->i_ino, ea_inode->i_nlink);
1001
1002 set_nlink(ea_inode, 1);
1003 ext4_orphan_del(handle, ea_inode);
1004
1005 if (ea_inode_cache) {
1006 hash = ext4_xattr_inode_get_hash(ea_inode);
1007 mb_cache_entry_create(ea_inode_cache,
1008 GFP_NOFS, hash,
1009 ea_inode->i_ino,
1010 true /* reusable */);
1011 }
1012 }
1013 } else {
1014 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1015 ea_inode->i_ino, ref_count);
1016
1017 if (ref_count == 0) {
1018 WARN_ONCE(ea_inode->i_nlink != 1,
1019 "EA inode %lu i_nlink=%u",
1020 ea_inode->i_ino, ea_inode->i_nlink);
1021
1022 clear_nlink(ea_inode);
1023 ext4_orphan_add(handle, ea_inode);
1024
1025 if (ea_inode_cache) {
1026 hash = ext4_xattr_inode_get_hash(ea_inode);
1027 mb_cache_entry_delete(ea_inode_cache, hash,
1028 ea_inode->i_ino);
1029 }
1030 }
1031 }
1032
1033 ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1034 if (ret)
1035 ext4_warning_inode(ea_inode,
1036 "ext4_mark_iloc_dirty() failed ret=%d", ret);
1037out:
1038 inode_unlock(ea_inode);
1039 return ret;
1040}
1041
1042static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1043{
1044 return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1045}
1046
1047static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1048{
1049 return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1050}
1051
1052static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1053 struct ext4_xattr_entry *first)
1054{
1055 struct inode *ea_inode;
1056 struct ext4_xattr_entry *entry;
1057 struct ext4_xattr_entry *failed_entry;
1058 unsigned int ea_ino;
1059 int err, saved_err;
1060
1061 for (entry = first; !IS_LAST_ENTRY(entry);
1062 entry = EXT4_XATTR_NEXT(entry)) {
1063 if (!entry->e_value_inum)
1064 continue;
1065 ea_ino = le32_to_cpu(entry->e_value_inum);
1066 err = ext4_xattr_inode_iget(parent, ea_ino,
1067 le32_to_cpu(entry->e_hash),
1068 &ea_inode);
1069 if (err)
1070 goto cleanup;
1071 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1072 if (err) {
1073 ext4_warning_inode(ea_inode, "inc ref error %d", err);
1074 iput(ea_inode);
1075 goto cleanup;
1076 }
1077 iput(ea_inode);
1078 }
1079 return 0;
1080
1081cleanup:
1082 saved_err = err;
1083 failed_entry = entry;
1084
1085 for (entry = first; entry != failed_entry;
1086 entry = EXT4_XATTR_NEXT(entry)) {
1087 if (!entry->e_value_inum)
1088 continue;
1089 ea_ino = le32_to_cpu(entry->e_value_inum);
1090 err = ext4_xattr_inode_iget(parent, ea_ino,
1091 le32_to_cpu(entry->e_hash),
1092 &ea_inode);
1093 if (err) {
1094 ext4_warning(parent->i_sb,
1095 "cleanup ea_ino %u iget error %d", ea_ino,
1096 err);
1097 continue;
1098 }
1099 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1100 if (err)
1101 ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1102 err);
1103 iput(ea_inode);
1104 }
1105 return saved_err;
1106}
1107
1108static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1109 struct buffer_head *bh, bool block_csum, bool dirty)
1110{
1111 int error;
1112
1113 if (bh && dirty) {
1114 if (block_csum)
1115 ext4_xattr_block_csum_set(inode, bh);
1116 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1117 if (error) {
1118 ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1119 error);
1120 return error;
1121 }
1122 }
1123 return 0;
1124}
1125
1126static void
1127ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1128 struct buffer_head *bh,
1129 struct ext4_xattr_entry *first, bool block_csum,
1130 struct ext4_xattr_inode_array **ea_inode_array,
1131 int extra_credits, bool skip_quota)
1132{
1133 struct inode *ea_inode;
1134 struct ext4_xattr_entry *entry;
1135 bool dirty = false;
1136 unsigned int ea_ino;
1137 int err;
1138 int credits;
1139
1140 /* One credit for dec ref on ea_inode, one for orphan list addition, */
1141 credits = 2 + extra_credits;
1142
1143 for (entry = first; !IS_LAST_ENTRY(entry);
1144 entry = EXT4_XATTR_NEXT(entry)) {
1145 if (!entry->e_value_inum)
1146 continue;
1147 ea_ino = le32_to_cpu(entry->e_value_inum);
1148 err = ext4_xattr_inode_iget(parent, ea_ino,
1149 le32_to_cpu(entry->e_hash),
1150 &ea_inode);
1151 if (err)
1152 continue;
1153
1154 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1155 if (err) {
1156 ext4_warning_inode(ea_inode,
1157 "Expand inode array err=%d", err);
1158 iput(ea_inode);
1159 continue;
1160 }
1161
1162 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1163 ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1164 ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1165 dirty));
1166 if (err < 0) {
1167 ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1168 err);
1169 continue;
1170 }
1171 if (err > 0) {
1172 err = ext4_journal_get_write_access(handle, bh);
1173 if (err) {
1174 ext4_warning_inode(ea_inode,
1175 "Re-get write access err=%d",
1176 err);
1177 continue;
1178 }
1179 }
1180
1181 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1182 if (err) {
1183 ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1184 err);
1185 continue;
1186 }
1187
1188 if (!skip_quota)
1189 ext4_xattr_inode_free_quota(parent, ea_inode,
1190 le32_to_cpu(entry->e_value_size));
1191
1192 /*
1193 * Forget about ea_inode within the same transaction that
1194 * decrements the ref count. This avoids duplicate decrements in
1195 * case the rest of the work spills over to subsequent
1196 * transactions.
1197 */
1198 entry->e_value_inum = 0;
1199 entry->e_value_size = 0;
1200
1201 dirty = true;
1202 }
1203
1204 if (dirty) {
1205 /*
1206 * Note that we are deliberately skipping csum calculation for
1207 * the final update because we do not expect any journal
1208 * restarts until xattr block is freed.
1209 */
1210
1211 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1212 if (err)
1213 ext4_warning_inode(parent,
1214 "handle dirty metadata err=%d", err);
1215 }
1216}
1217
1218/*
1219 * Release the xattr block BH: If the reference count is > 1, decrement it;
1220 * otherwise free the block.
1221 */
1222static void
1223ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1224 struct buffer_head *bh,
1225 struct ext4_xattr_inode_array **ea_inode_array,
1226 int extra_credits)
1227{
1228 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1229 u32 hash, ref;
1230 int error = 0;
1231
1232 BUFFER_TRACE(bh, "get_write_access");
1233 error = ext4_journal_get_write_access(handle, bh);
1234 if (error)
1235 goto out;
1236
1237 lock_buffer(bh);
1238 hash = le32_to_cpu(BHDR(bh)->h_hash);
1239 ref = le32_to_cpu(BHDR(bh)->h_refcount);
1240 if (ref == 1) {
1241 ea_bdebug(bh, "refcount now=0; freeing");
1242 /*
1243 * This must happen under buffer lock for
1244 * ext4_xattr_block_set() to reliably detect freed block
1245 */
1246 if (ea_block_cache)
1247 mb_cache_entry_delete(ea_block_cache, hash,
1248 bh->b_blocknr);
1249 get_bh(bh);
1250 unlock_buffer(bh);
1251
1252 if (ext4_has_feature_ea_inode(inode->i_sb))
1253 ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1254 BFIRST(bh),
1255 true /* block_csum */,
1256 ea_inode_array,
1257 extra_credits,
1258 true /* skip_quota */);
1259 ext4_free_blocks(handle, inode, bh, 0, 1,
1260 EXT4_FREE_BLOCKS_METADATA |
1261 EXT4_FREE_BLOCKS_FORGET);
1262 } else {
1263 ref--;
1264 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1265 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1266 struct mb_cache_entry *ce;
1267
1268 if (ea_block_cache) {
1269 ce = mb_cache_entry_get(ea_block_cache, hash,
1270 bh->b_blocknr);
1271 if (ce) {
1272 ce->e_reusable = 1;
1273 mb_cache_entry_put(ea_block_cache, ce);
1274 }
1275 }
1276 }
1277
1278 ext4_xattr_block_csum_set(inode, bh);
1279 /*
1280 * Beware of this ugliness: Releasing of xattr block references
1281 * from different inodes can race and so we have to protect
1282 * from a race where someone else frees the block (and releases
1283 * its journal_head) before we are done dirtying the buffer. In
1284 * nojournal mode this race is harmless and we actually cannot
1285 * call ext4_handle_dirty_metadata() with locked buffer as
1286 * that function can call sync_dirty_buffer() so for that case
1287 * we handle the dirtying after unlocking the buffer.
1288 */
1289 if (ext4_handle_valid(handle))
1290 error = ext4_handle_dirty_metadata(handle, inode, bh);
1291 unlock_buffer(bh);
1292 if (!ext4_handle_valid(handle))
1293 error = ext4_handle_dirty_metadata(handle, inode, bh);
1294 if (IS_SYNC(inode))
1295 ext4_handle_sync(handle);
1296 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1297 ea_bdebug(bh, "refcount now=%d; releasing",
1298 le32_to_cpu(BHDR(bh)->h_refcount));
1299 }
1300out:
1301 ext4_std_error(inode->i_sb, error);
1302 return;
1303}
1304
1305/*
1306 * Find the available free space for EAs. This also returns the total number of
1307 * bytes used by EA entries.
1308 */
1309static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1310 size_t *min_offs, void *base, int *total)
1311{
1312 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1313 if (!last->e_value_inum && last->e_value_size) {
1314 size_t offs = le16_to_cpu(last->e_value_offs);
1315 if (offs < *min_offs)
1316 *min_offs = offs;
1317 }
1318 if (total)
1319 *total += EXT4_XATTR_LEN(last->e_name_len);
1320 }
1321 return (*min_offs - ((void *)last - base) - sizeof(__u32));
1322}
1323
1324/*
1325 * Write the value of the EA in an inode.
1326 */
1327static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1328 const void *buf, int bufsize)
1329{
1330 struct buffer_head *bh = NULL;
1331 unsigned long block = 0;
1332 int blocksize = ea_inode->i_sb->s_blocksize;
1333 int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1334 int csize, wsize = 0;
1335 int ret = 0, ret2 = 0;
1336 int retries = 0;
1337
1338retry:
1339 while (ret >= 0 && ret < max_blocks) {
1340 struct ext4_map_blocks map;
1341 map.m_lblk = block += ret;
1342 map.m_len = max_blocks -= ret;
1343
1344 ret = ext4_map_blocks(handle, ea_inode, &map,
1345 EXT4_GET_BLOCKS_CREATE);
1346 if (ret <= 0) {
1347 ext4_mark_inode_dirty(handle, ea_inode);
1348 if (ret == -ENOSPC &&
1349 ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1350 ret = 0;
1351 goto retry;
1352 }
1353 break;
1354 }
1355 }
1356
1357 if (ret < 0)
1358 return ret;
1359
1360 block = 0;
1361 while (wsize < bufsize) {
1362 brelse(bh);
1363 csize = (bufsize - wsize) > blocksize ? blocksize :
1364 bufsize - wsize;
1365 bh = ext4_getblk(handle, ea_inode, block, 0);
1366 if (IS_ERR(bh))
1367 return PTR_ERR(bh);
1368 if (!bh) {
1369 WARN_ON_ONCE(1);
1370 EXT4_ERROR_INODE(ea_inode,
1371 "ext4_getblk() return bh = NULL");
1372 return -EFSCORRUPTED;
1373 }
1374 ret = ext4_journal_get_write_access(handle, bh);
1375 if (ret)
1376 goto out;
1377
1378 memcpy(bh->b_data, buf, csize);
1379 set_buffer_uptodate(bh);
1380 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1381
1382 buf += csize;
1383 wsize += csize;
1384 block += 1;
1385 }
1386
1387 inode_lock(ea_inode);
1388 i_size_write(ea_inode, wsize);
1389 ext4_update_i_disksize(ea_inode, wsize);
1390 inode_unlock(ea_inode);
1391
1392 ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1393 if (unlikely(ret2 && !ret))
1394 ret = ret2;
1395
1396out:
1397 brelse(bh);
1398
1399 return ret;
1400}
1401
1402/*
1403 * Create an inode to store the value of a large EA.
1404 */
1405static struct inode *ext4_xattr_inode_create(handle_t *handle,
1406 struct inode *inode, u32 hash)
1407{
1408 struct inode *ea_inode = NULL;
1409 uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1410 int err;
1411
1412 /*
1413 * Let the next inode be the goal, so we try and allocate the EA inode
1414 * in the same group, or nearby one.
1415 */
1416 ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1417 S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1418 EXT4_EA_INODE_FL);
1419 if (!IS_ERR(ea_inode)) {
1420 ea_inode->i_op = &ext4_file_inode_operations;
1421 ea_inode->i_fop = &ext4_file_operations;
1422 ext4_set_aops(ea_inode);
1423 ext4_xattr_inode_set_class(ea_inode);
1424 unlock_new_inode(ea_inode);
1425 ext4_xattr_inode_set_ref(ea_inode, 1);
1426 ext4_xattr_inode_set_hash(ea_inode, hash);
1427 err = ext4_mark_inode_dirty(handle, ea_inode);
1428 if (!err)
1429 err = ext4_inode_attach_jinode(ea_inode);
1430 if (err) {
1431 iput(ea_inode);
1432 return ERR_PTR(err);
1433 }
1434
1435 /*
1436 * Xattr inodes are shared therefore quota charging is performed
1437 * at a higher level.
1438 */
1439 dquot_free_inode(ea_inode);
1440 dquot_drop(ea_inode);
1441 inode_lock(ea_inode);
1442 ea_inode->i_flags |= S_NOQUOTA;
1443 inode_unlock(ea_inode);
1444 }
1445
1446 return ea_inode;
1447}
1448
1449static struct inode *
1450ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1451 size_t value_len, u32 hash)
1452{
1453 struct inode *ea_inode;
1454 struct mb_cache_entry *ce;
1455 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1456 void *ea_data;
1457
1458 if (!ea_inode_cache)
1459 return NULL;
1460
1461 ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1462 if (!ce)
1463 return NULL;
1464
1465 WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1466 !(current->flags & PF_MEMALLOC_NOFS));
1467
1468 ea_data = kvmalloc(value_len, GFP_KERNEL);
1469 if (!ea_data) {
1470 mb_cache_entry_put(ea_inode_cache, ce);
1471 return NULL;
1472 }
1473
1474 while (ce) {
1475 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1476 EXT4_IGET_NORMAL);
1477 if (!IS_ERR(ea_inode) &&
1478 !is_bad_inode(ea_inode) &&
1479 (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1480 i_size_read(ea_inode) == value_len &&
1481 !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1482 !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1483 value_len) &&
1484 !memcmp(value, ea_data, value_len)) {
1485 mb_cache_entry_touch(ea_inode_cache, ce);
1486 mb_cache_entry_put(ea_inode_cache, ce);
1487 kvfree(ea_data);
1488 return ea_inode;
1489 }
1490
1491 if (!IS_ERR(ea_inode))
1492 iput(ea_inode);
1493 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1494 }
1495 kvfree(ea_data);
1496 return NULL;
1497}
1498
1499/*
1500 * Add value of the EA in an inode.
1501 */
1502static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1503 const void *value, size_t value_len,
1504 struct inode **ret_inode)
1505{
1506 struct inode *ea_inode;
1507 u32 hash;
1508 int err;
1509
1510 hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1511 ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1512 if (ea_inode) {
1513 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1514 if (err) {
1515 iput(ea_inode);
1516 return err;
1517 }
1518
1519 *ret_inode = ea_inode;
1520 return 0;
1521 }
1522
1523 /* Create an inode for the EA value */
1524 ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1525 if (IS_ERR(ea_inode))
1526 return PTR_ERR(ea_inode);
1527
1528 err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1529 if (err) {
1530 ext4_xattr_inode_dec_ref(handle, ea_inode);
1531 iput(ea_inode);
1532 return err;
1533 }
1534
1535 if (EA_INODE_CACHE(inode))
1536 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1537 ea_inode->i_ino, true /* reusable */);
1538
1539 *ret_inode = ea_inode;
1540 return 0;
1541}
1542
1543/*
1544 * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1545 * feature is enabled.
1546 */
1547#define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1548
1549static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1550 struct ext4_xattr_search *s,
1551 handle_t *handle, struct inode *inode,
1552 bool is_block)
1553{
1554 struct ext4_xattr_entry *last, *next;
1555 struct ext4_xattr_entry *here = s->here;
1556 size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1557 int in_inode = i->in_inode;
1558 struct inode *old_ea_inode = NULL;
1559 struct inode *new_ea_inode = NULL;
1560 size_t old_size, new_size;
1561 int ret;
1562
1563 /* Space used by old and new values. */
1564 old_size = (!s->not_found && !here->e_value_inum) ?
1565 EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1566 new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1567
1568 /*
1569 * Optimization for the simple case when old and new values have the
1570 * same padded sizes. Not applicable if external inodes are involved.
1571 */
1572 if (new_size && new_size == old_size) {
1573 size_t offs = le16_to_cpu(here->e_value_offs);
1574 void *val = s->base + offs;
1575
1576 here->e_value_size = cpu_to_le32(i->value_len);
1577 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1578 memset(val, 0, new_size);
1579 } else {
1580 memcpy(val, i->value, i->value_len);
1581 /* Clear padding bytes. */
1582 memset(val + i->value_len, 0, new_size - i->value_len);
1583 }
1584 goto update_hash;
1585 }
1586
1587 /* Compute min_offs and last. */
1588 last = s->first;
1589 for (; !IS_LAST_ENTRY(last); last = next) {
1590 next = EXT4_XATTR_NEXT(last);
1591 if ((void *)next >= s->end) {
1592 EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1593 ret = -EFSCORRUPTED;
1594 goto out;
1595 }
1596 if (!last->e_value_inum && last->e_value_size) {
1597 size_t offs = le16_to_cpu(last->e_value_offs);
1598 if (offs < min_offs)
1599 min_offs = offs;
1600 }
1601 }
1602
1603 /* Check whether we have enough space. */
1604 if (i->value) {
1605 size_t free;
1606
1607 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1608 if (!s->not_found)
1609 free += EXT4_XATTR_LEN(name_len) + old_size;
1610
1611 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1612 ret = -ENOSPC;
1613 goto out;
1614 }
1615
1616 /*
1617 * If storing the value in an external inode is an option,
1618 * reserve space for xattr entries/names in the external
1619 * attribute block so that a long value does not occupy the
1620 * whole space and prevent further entries being added.
1621 */
1622 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1623 new_size && is_block &&
1624 (min_offs + old_size - new_size) <
1625 EXT4_XATTR_BLOCK_RESERVE(inode)) {
1626 ret = -ENOSPC;
1627 goto out;
1628 }
1629 }
1630
1631 /*
1632 * Getting access to old and new ea inodes is subject to failures.
1633 * Finish that work before doing any modifications to the xattr data.
1634 */
1635 if (!s->not_found && here->e_value_inum) {
1636 ret = ext4_xattr_inode_iget(inode,
1637 le32_to_cpu(here->e_value_inum),
1638 le32_to_cpu(here->e_hash),
1639 &old_ea_inode);
1640 if (ret) {
1641 old_ea_inode = NULL;
1642 goto out;
1643 }
1644 }
1645 if (i->value && in_inode) {
1646 WARN_ON_ONCE(!i->value_len);
1647
1648 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1649 if (ret)
1650 goto out;
1651
1652 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1653 i->value_len,
1654 &new_ea_inode);
1655 if (ret) {
1656 new_ea_inode = NULL;
1657 ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1658 goto out;
1659 }
1660 }
1661
1662 if (old_ea_inode) {
1663 /* We are ready to release ref count on the old_ea_inode. */
1664 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1665 if (ret) {
1666 /* Release newly required ref count on new_ea_inode. */
1667 if (new_ea_inode) {
1668 int err;
1669
1670 err = ext4_xattr_inode_dec_ref(handle,
1671 new_ea_inode);
1672 if (err)
1673 ext4_warning_inode(new_ea_inode,
1674 "dec ref new_ea_inode err=%d",
1675 err);
1676 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1677 i->value_len);
1678 }
1679 goto out;
1680 }
1681
1682 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1683 le32_to_cpu(here->e_value_size));
1684 }
1685
1686 /* No failures allowed past this point. */
1687
1688 if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1689 /* Remove the old value. */
1690 void *first_val = s->base + min_offs;
1691 size_t offs = le16_to_cpu(here->e_value_offs);
1692 void *val = s->base + offs;
1693
1694 memmove(first_val + old_size, first_val, val - first_val);
1695 memset(first_val, 0, old_size);
1696 min_offs += old_size;
1697
1698 /* Adjust all value offsets. */
1699 last = s->first;
1700 while (!IS_LAST_ENTRY(last)) {
1701 size_t o = le16_to_cpu(last->e_value_offs);
1702
1703 if (!last->e_value_inum &&
1704 last->e_value_size && o < offs)
1705 last->e_value_offs = cpu_to_le16(o + old_size);
1706 last = EXT4_XATTR_NEXT(last);
1707 }
1708 }
1709
1710 if (!i->value) {
1711 /* Remove old name. */
1712 size_t size = EXT4_XATTR_LEN(name_len);
1713
1714 last = ENTRY((void *)last - size);
1715 memmove(here, (void *)here + size,
1716 (void *)last - (void *)here + sizeof(__u32));
1717 memset(last, 0, size);
1718 } else if (s->not_found) {
1719 /* Insert new name. */
1720 size_t size = EXT4_XATTR_LEN(name_len);
1721 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1722
1723 memmove((void *)here + size, here, rest);
1724 memset(here, 0, size);
1725 here->e_name_index = i->name_index;
1726 here->e_name_len = name_len;
1727 memcpy(here->e_name, i->name, name_len);
1728 } else {
1729 /* This is an update, reset value info. */
1730 here->e_value_inum = 0;
1731 here->e_value_offs = 0;
1732 here->e_value_size = 0;
1733 }
1734
1735 if (i->value) {
1736 /* Insert new value. */
1737 if (in_inode) {
1738 here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1739 } else if (i->value_len) {
1740 void *val = s->base + min_offs - new_size;
1741
1742 here->e_value_offs = cpu_to_le16(min_offs - new_size);
1743 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1744 memset(val, 0, new_size);
1745 } else {
1746 memcpy(val, i->value, i->value_len);
1747 /* Clear padding bytes. */
1748 memset(val + i->value_len, 0,
1749 new_size - i->value_len);
1750 }
1751 }
1752 here->e_value_size = cpu_to_le32(i->value_len);
1753 }
1754
1755update_hash:
1756 if (i->value) {
1757 __le32 hash = 0;
1758
1759 /* Entry hash calculation. */
1760 if (in_inode) {
1761 __le32 crc32c_hash;
1762
1763 /*
1764 * Feed crc32c hash instead of the raw value for entry
1765 * hash calculation. This is to avoid walking
1766 * potentially long value buffer again.
1767 */
1768 crc32c_hash = cpu_to_le32(
1769 ext4_xattr_inode_get_hash(new_ea_inode));
1770 hash = ext4_xattr_hash_entry(here->e_name,
1771 here->e_name_len,
1772 &crc32c_hash, 1);
1773 } else if (is_block) {
1774 __le32 *value = s->base + le16_to_cpu(
1775 here->e_value_offs);
1776
1777 hash = ext4_xattr_hash_entry(here->e_name,
1778 here->e_name_len, value,
1779 new_size >> 2);
1780 }
1781 here->e_hash = hash;
1782 }
1783
1784 if (is_block)
1785 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1786
1787 ret = 0;
1788out:
1789 iput(old_ea_inode);
1790 iput(new_ea_inode);
1791 return ret;
1792}
1793
1794struct ext4_xattr_block_find {
1795 struct ext4_xattr_search s;
1796 struct buffer_head *bh;
1797};
1798
1799static int
1800ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1801 struct ext4_xattr_block_find *bs)
1802{
1803 struct super_block *sb = inode->i_sb;
1804 int error;
1805
1806 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1807 i->name_index, i->name, i->value, (long)i->value_len);
1808
1809 if (EXT4_I(inode)->i_file_acl) {
1810 /* The inode already has an extended attribute block. */
1811 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1812 if (IS_ERR(bs->bh)) {
1813 error = PTR_ERR(bs->bh);
1814 bs->bh = NULL;
1815 return error;
1816 }
1817 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1818 atomic_read(&(bs->bh->b_count)),
1819 le32_to_cpu(BHDR(bs->bh)->h_refcount));
1820 error = ext4_xattr_check_block(inode, bs->bh);
1821 if (error)
1822 return error;
1823 /* Find the named attribute. */
1824 bs->s.base = BHDR(bs->bh);
1825 bs->s.first = BFIRST(bs->bh);
1826 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1827 bs->s.here = bs->s.first;
1828 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1829 i->name_index, i->name, 1);
1830 if (error && error != -ENODATA)
1831 return error;
1832 bs->s.not_found = error;
1833 }
1834 return 0;
1835}
1836
1837static int
1838ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1839 struct ext4_xattr_info *i,
1840 struct ext4_xattr_block_find *bs)
1841{
1842 struct super_block *sb = inode->i_sb;
1843 struct buffer_head *new_bh = NULL;
1844 struct ext4_xattr_search s_copy = bs->s;
1845 struct ext4_xattr_search *s = &s_copy;
1846 struct mb_cache_entry *ce = NULL;
1847 int error = 0;
1848 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1849 struct inode *ea_inode = NULL, *tmp_inode;
1850 size_t old_ea_inode_quota = 0;
1851 unsigned int ea_ino;
1852
1853
1854#define header(x) ((struct ext4_xattr_header *)(x))
1855
1856 if (s->base) {
1857 BUFFER_TRACE(bs->bh, "get_write_access");
1858 error = ext4_journal_get_write_access(handle, bs->bh);
1859 if (error)
1860 goto cleanup;
1861 lock_buffer(bs->bh);
1862
1863 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1864 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1865
1866 /*
1867 * This must happen under buffer lock for
1868 * ext4_xattr_block_set() to reliably detect modified
1869 * block
1870 */
1871 if (ea_block_cache)
1872 mb_cache_entry_delete(ea_block_cache, hash,
1873 bs->bh->b_blocknr);
1874 ea_bdebug(bs->bh, "modifying in-place");
1875 error = ext4_xattr_set_entry(i, s, handle, inode,
1876 true /* is_block */);
1877 ext4_xattr_block_csum_set(inode, bs->bh);
1878 unlock_buffer(bs->bh);
1879 if (error == -EFSCORRUPTED)
1880 goto bad_block;
1881 if (!error)
1882 error = ext4_handle_dirty_metadata(handle,
1883 inode,
1884 bs->bh);
1885 if (error)
1886 goto cleanup;
1887 goto inserted;
1888 } else {
1889 int offset = (char *)s->here - bs->bh->b_data;
1890
1891 unlock_buffer(bs->bh);
1892 ea_bdebug(bs->bh, "cloning");
1893 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1894 error = -ENOMEM;
1895 if (s->base == NULL)
1896 goto cleanup;
1897 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1898 s->first = ENTRY(header(s->base)+1);
1899 header(s->base)->h_refcount = cpu_to_le32(1);
1900 s->here = ENTRY(s->base + offset);
1901 s->end = s->base + bs->bh->b_size;
1902
1903 /*
1904 * If existing entry points to an xattr inode, we need
1905 * to prevent ext4_xattr_set_entry() from decrementing
1906 * ref count on it because the reference belongs to the
1907 * original block. In this case, make the entry look
1908 * like it has an empty value.
1909 */
1910 if (!s->not_found && s->here->e_value_inum) {
1911 ea_ino = le32_to_cpu(s->here->e_value_inum);
1912 error = ext4_xattr_inode_iget(inode, ea_ino,
1913 le32_to_cpu(s->here->e_hash),
1914 &tmp_inode);
1915 if (error)
1916 goto cleanup;
1917
1918 if (!ext4_test_inode_state(tmp_inode,
1919 EXT4_STATE_LUSTRE_EA_INODE)) {
1920 /*
1921 * Defer quota free call for previous
1922 * inode until success is guaranteed.
1923 */
1924 old_ea_inode_quota = le32_to_cpu(
1925 s->here->e_value_size);
1926 }
1927 iput(tmp_inode);
1928
1929 s->here->e_value_inum = 0;
1930 s->here->e_value_size = 0;
1931 }
1932 }
1933 } else {
1934 /* Allocate a buffer where we construct the new block. */
1935 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1936 error = -ENOMEM;
1937 if (s->base == NULL)
1938 goto cleanup;
1939 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1940 header(s->base)->h_blocks = cpu_to_le32(1);
1941 header(s->base)->h_refcount = cpu_to_le32(1);
1942 s->first = ENTRY(header(s->base)+1);
1943 s->here = ENTRY(header(s->base)+1);
1944 s->end = s->base + sb->s_blocksize;
1945 }
1946
1947 error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1948 if (error == -EFSCORRUPTED)
1949 goto bad_block;
1950 if (error)
1951 goto cleanup;
1952
1953 if (i->value && s->here->e_value_inum) {
1954 /*
1955 * A ref count on ea_inode has been taken as part of the call to
1956 * ext4_xattr_set_entry() above. We would like to drop this
1957 * extra ref but we have to wait until the xattr block is
1958 * initialized and has its own ref count on the ea_inode.
1959 */
1960 ea_ino = le32_to_cpu(s->here->e_value_inum);
1961 error = ext4_xattr_inode_iget(inode, ea_ino,
1962 le32_to_cpu(s->here->e_hash),
1963 &ea_inode);
1964 if (error) {
1965 ea_inode = NULL;
1966 goto cleanup;
1967 }
1968 }
1969
1970inserted:
1971 if (!IS_LAST_ENTRY(s->first)) {
1972 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1973 &ce);
1974 if (new_bh) {
1975 /* We found an identical block in the cache. */
1976 if (new_bh == bs->bh)
1977 ea_bdebug(new_bh, "keeping");
1978 else {
1979 u32 ref;
1980
1981 WARN_ON_ONCE(dquot_initialize_needed(inode));
1982
1983 /* The old block is released after updating
1984 the inode. */
1985 error = dquot_alloc_block(inode,
1986 EXT4_C2B(EXT4_SB(sb), 1));
1987 if (error)
1988 goto cleanup;
1989 BUFFER_TRACE(new_bh, "get_write_access");
1990 error = ext4_journal_get_write_access(handle,
1991 new_bh);
1992 if (error)
1993 goto cleanup_dquot;
1994 lock_buffer(new_bh);
1995 /*
1996 * We have to be careful about races with
1997 * freeing, rehashing or adding references to
1998 * xattr block. Once we hold buffer lock xattr
1999 * block's state is stable so we can check
2000 * whether the block got freed / rehashed or
2001 * not. Since we unhash mbcache entry under
2002 * buffer lock when freeing / rehashing xattr
2003 * block, checking whether entry is still
2004 * hashed is reliable. Same rules hold for
2005 * e_reusable handling.
2006 */
2007 if (hlist_bl_unhashed(&ce->e_hash_list) ||
2008 !ce->e_reusable) {
2009 /*
2010 * Undo everything and check mbcache
2011 * again.
2012 */
2013 unlock_buffer(new_bh);
2014 dquot_free_block(inode,
2015 EXT4_C2B(EXT4_SB(sb),
2016 1));
2017 brelse(new_bh);
2018 mb_cache_entry_put(ea_block_cache, ce);
2019 ce = NULL;
2020 new_bh = NULL;
2021 goto inserted;
2022 }
2023 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2024 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2025 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2026 ce->e_reusable = 0;
2027 ea_bdebug(new_bh, "reusing; refcount now=%d",
2028 ref);
2029 ext4_xattr_block_csum_set(inode, new_bh);
2030 unlock_buffer(new_bh);
2031 error = ext4_handle_dirty_metadata(handle,
2032 inode,
2033 new_bh);
2034 if (error)
2035 goto cleanup_dquot;
2036 }
2037 mb_cache_entry_touch(ea_block_cache, ce);
2038 mb_cache_entry_put(ea_block_cache, ce);
2039 ce = NULL;
2040 } else if (bs->bh && s->base == bs->bh->b_data) {
2041 /* We were modifying this block in-place. */
2042 ea_bdebug(bs->bh, "keeping this block");
2043 ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2044 new_bh = bs->bh;
2045 get_bh(new_bh);
2046 } else {
2047 /* We need to allocate a new block */
2048 ext4_fsblk_t goal, block;
2049
2050 WARN_ON_ONCE(dquot_initialize_needed(inode));
2051
2052 goal = ext4_group_first_block_no(sb,
2053 EXT4_I(inode)->i_block_group);
2054
2055 /* non-extent files can't have physical blocks past 2^32 */
2056 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2057 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2058
2059 block = ext4_new_meta_blocks(handle, inode, goal, 0,
2060 NULL, &error);
2061 if (error)
2062 goto cleanup;
2063
2064 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2065 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2066
2067 ea_idebug(inode, "creating block %llu",
2068 (unsigned long long)block);
2069
2070 new_bh = sb_getblk(sb, block);
2071 if (unlikely(!new_bh)) {
2072 error = -ENOMEM;
2073getblk_failed:
2074 ext4_free_blocks(handle, inode, NULL, block, 1,
2075 EXT4_FREE_BLOCKS_METADATA);
2076 goto cleanup;
2077 }
2078 error = ext4_xattr_inode_inc_ref_all(handle, inode,
2079 ENTRY(header(s->base)+1));
2080 if (error)
2081 goto getblk_failed;
2082 if (ea_inode) {
2083 /* Drop the extra ref on ea_inode. */
2084 error = ext4_xattr_inode_dec_ref(handle,
2085 ea_inode);
2086 if (error)
2087 ext4_warning_inode(ea_inode,
2088 "dec ref error=%d",
2089 error);
2090 iput(ea_inode);
2091 ea_inode = NULL;
2092 }
2093
2094 lock_buffer(new_bh);
2095 error = ext4_journal_get_create_access(handle, new_bh);
2096 if (error) {
2097 unlock_buffer(new_bh);
2098 error = -EIO;
2099 goto getblk_failed;
2100 }
2101 memcpy(new_bh->b_data, s->base, new_bh->b_size);
2102 ext4_xattr_block_csum_set(inode, new_bh);
2103 set_buffer_uptodate(new_bh);
2104 unlock_buffer(new_bh);
2105 ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2106 error = ext4_handle_dirty_metadata(handle, inode,
2107 new_bh);
2108 if (error)
2109 goto cleanup;
2110 }
2111 }
2112
2113 if (old_ea_inode_quota)
2114 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2115
2116 /* Update the inode. */
2117 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2118
2119 /* Drop the previous xattr block. */
2120 if (bs->bh && bs->bh != new_bh) {
2121 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2122
2123 ext4_xattr_release_block(handle, inode, bs->bh,
2124 &ea_inode_array,
2125 0 /* extra_credits */);
2126 ext4_xattr_inode_array_free(ea_inode_array);
2127 }
2128 error = 0;
2129
2130cleanup:
2131 if (ea_inode) {
2132 int error2;
2133
2134 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2135 if (error2)
2136 ext4_warning_inode(ea_inode, "dec ref error=%d",
2137 error2);
2138
2139 /* If there was an error, revert the quota charge. */
2140 if (error)
2141 ext4_xattr_inode_free_quota(inode, ea_inode,
2142 i_size_read(ea_inode));
2143 iput(ea_inode);
2144 }
2145 if (ce)
2146 mb_cache_entry_put(ea_block_cache, ce);
2147 brelse(new_bh);
2148 if (!(bs->bh && s->base == bs->bh->b_data))
2149 kfree(s->base);
2150
2151 return error;
2152
2153cleanup_dquot:
2154 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2155 goto cleanup;
2156
2157bad_block:
2158 EXT4_ERROR_INODE(inode, "bad block %llu",
2159 EXT4_I(inode)->i_file_acl);
2160 goto cleanup;
2161
2162#undef header
2163}
2164
2165int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2166 struct ext4_xattr_ibody_find *is)
2167{
2168 struct ext4_xattr_ibody_header *header;
2169 struct ext4_inode *raw_inode;
2170 int error;
2171
2172 if (EXT4_I(inode)->i_extra_isize == 0)
2173 return 0;
2174 raw_inode = ext4_raw_inode(&is->iloc);
2175 header = IHDR(inode, raw_inode);
2176 is->s.base = is->s.first = IFIRST(header);
2177 is->s.here = is->s.first;
2178 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2179 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2180 error = xattr_check_inode(inode, header, is->s.end);
2181 if (error)
2182 return error;
2183 /* Find the named attribute. */
2184 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2185 i->name_index, i->name, 0);
2186 if (error && error != -ENODATA)
2187 return error;
2188 is->s.not_found = error;
2189 }
2190 return 0;
2191}
2192
2193int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2194 struct ext4_xattr_info *i,
2195 struct ext4_xattr_ibody_find *is)
2196{
2197 struct ext4_xattr_ibody_header *header;
2198 struct ext4_xattr_search *s = &is->s;
2199 int error;
2200
2201 if (EXT4_I(inode)->i_extra_isize == 0)
2202 return -ENOSPC;
2203 error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2204 if (error)
2205 return error;
2206 header = IHDR(inode, ext4_raw_inode(&is->iloc));
2207 if (!IS_LAST_ENTRY(s->first)) {
2208 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2209 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2210 } else {
2211 header->h_magic = cpu_to_le32(0);
2212 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2213 }
2214 return 0;
2215}
2216
2217static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2218 struct ext4_xattr_info *i)
2219{
2220 void *value;
2221
2222 /* When e_value_inum is set the value is stored externally. */
2223 if (s->here->e_value_inum)
2224 return 0;
2225 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2226 return 0;
2227 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2228 return !memcmp(value, i->value, i->value_len);
2229}
2230
2231static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2232{
2233 struct buffer_head *bh;
2234 int error;
2235
2236 if (!EXT4_I(inode)->i_file_acl)
2237 return NULL;
2238 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2239 if (IS_ERR(bh))
2240 return bh;
2241 error = ext4_xattr_check_block(inode, bh);
2242 if (error) {
2243 brelse(bh);
2244 return ERR_PTR(error);
2245 }
2246 return bh;
2247}
2248
2249/*
2250 * ext4_xattr_set_handle()
2251 *
2252 * Create, replace or remove an extended attribute for this inode. Value
2253 * is NULL to remove an existing extended attribute, and non-NULL to
2254 * either replace an existing extended attribute, or create a new extended
2255 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2256 * specify that an extended attribute must exist and must not exist
2257 * previous to the call, respectively.
2258 *
2259 * Returns 0, or a negative error number on failure.
2260 */
2261int
2262ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2263 const char *name, const void *value, size_t value_len,
2264 int flags)
2265{
2266 struct ext4_xattr_info i = {
2267 .name_index = name_index,
2268 .name = name,
2269 .value = value,
2270 .value_len = value_len,
2271 .in_inode = 0,
2272 };
2273 struct ext4_xattr_ibody_find is = {
2274 .s = { .not_found = -ENODATA, },
2275 };
2276 struct ext4_xattr_block_find bs = {
2277 .s = { .not_found = -ENODATA, },
2278 };
2279 int no_expand;
2280 int error;
2281
2282 if (!name)
2283 return -EINVAL;
2284 if (strlen(name) > 255)
2285 return -ERANGE;
2286
2287 ext4_write_lock_xattr(inode, &no_expand);
2288
2289 /* Check journal credits under write lock. */
2290 if (ext4_handle_valid(handle)) {
2291 struct buffer_head *bh;
2292 int credits;
2293
2294 bh = ext4_xattr_get_block(inode);
2295 if (IS_ERR(bh)) {
2296 error = PTR_ERR(bh);
2297 goto cleanup;
2298 }
2299
2300 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2301 value_len,
2302 flags & XATTR_CREATE);
2303 brelse(bh);
2304
2305 if (jbd2_handle_buffer_credits(handle) < credits) {
2306 error = -ENOSPC;
2307 goto cleanup;
2308 }
2309 WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2310 }
2311
2312 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2313 if (error)
2314 goto cleanup;
2315
2316 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2317 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2318 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2319 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2320 }
2321
2322 error = ext4_xattr_ibody_find(inode, &i, &is);
2323 if (error)
2324 goto cleanup;
2325 if (is.s.not_found)
2326 error = ext4_xattr_block_find(inode, &i, &bs);
2327 if (error)
2328 goto cleanup;
2329 if (is.s.not_found && bs.s.not_found) {
2330 error = -ENODATA;
2331 if (flags & XATTR_REPLACE)
2332 goto cleanup;
2333 error = 0;
2334 if (!value)
2335 goto cleanup;
2336 } else {
2337 error = -EEXIST;
2338 if (flags & XATTR_CREATE)
2339 goto cleanup;
2340 }
2341
2342 if (!value) {
2343 if (!is.s.not_found)
2344 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2345 else if (!bs.s.not_found)
2346 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2347 } else {
2348 error = 0;
2349 /* Xattr value did not change? Save us some work and bail out */
2350 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2351 goto cleanup;
2352 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2353 goto cleanup;
2354
2355 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2356 (EXT4_XATTR_SIZE(i.value_len) >
2357 EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2358 i.in_inode = 1;
2359retry_inode:
2360 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2361 if (!error && !bs.s.not_found) {
2362 i.value = NULL;
2363 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2364 } else if (error == -ENOSPC) {
2365 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2366 brelse(bs.bh);
2367 bs.bh = NULL;
2368 error = ext4_xattr_block_find(inode, &i, &bs);
2369 if (error)
2370 goto cleanup;
2371 }
2372 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2373 if (!error && !is.s.not_found) {
2374 i.value = NULL;
2375 error = ext4_xattr_ibody_set(handle, inode, &i,
2376 &is);
2377 } else if (error == -ENOSPC) {
2378 /*
2379 * Xattr does not fit in the block, store at
2380 * external inode if possible.
2381 */
2382 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2383 i.value_len && !i.in_inode) {
2384 i.in_inode = 1;
2385 goto retry_inode;
2386 }
2387 }
2388 }
2389 }
2390 if (!error) {
2391 ext4_xattr_update_super_block(handle, inode->i_sb);
2392 inode->i_ctime = current_time(inode);
2393 if (!value)
2394 no_expand = 0;
2395 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2396 /*
2397 * The bh is consumed by ext4_mark_iloc_dirty, even with
2398 * error != 0.
2399 */
2400 is.iloc.bh = NULL;
2401 if (IS_SYNC(inode))
2402 ext4_handle_sync(handle);
2403 }
2404 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2405
2406cleanup:
2407 brelse(is.iloc.bh);
2408 brelse(bs.bh);
2409 ext4_write_unlock_xattr(inode, &no_expand);
2410 return error;
2411}
2412
2413int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2414 bool is_create, int *credits)
2415{
2416 struct buffer_head *bh;
2417 int err;
2418
2419 *credits = 0;
2420
2421 if (!EXT4_SB(inode->i_sb)->s_journal)
2422 return 0;
2423
2424 down_read(&EXT4_I(inode)->xattr_sem);
2425
2426 bh = ext4_xattr_get_block(inode);
2427 if (IS_ERR(bh)) {
2428 err = PTR_ERR(bh);
2429 } else {
2430 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2431 value_len, is_create);
2432 brelse(bh);
2433 err = 0;
2434 }
2435
2436 up_read(&EXT4_I(inode)->xattr_sem);
2437 return err;
2438}
2439
2440/*
2441 * ext4_xattr_set()
2442 *
2443 * Like ext4_xattr_set_handle, but start from an inode. This extended
2444 * attribute modification is a filesystem transaction by itself.
2445 *
2446 * Returns 0, or a negative error number on failure.
2447 */
2448int
2449ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2450 const void *value, size_t value_len, int flags)
2451{
2452 handle_t *handle;
2453 struct super_block *sb = inode->i_sb;
2454 int error, retries = 0;
2455 int credits;
2456
2457 error = dquot_initialize(inode);
2458 if (error)
2459 return error;
2460
2461retry:
2462 error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2463 &credits);
2464 if (error)
2465 return error;
2466
2467 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2468 if (IS_ERR(handle)) {
2469 error = PTR_ERR(handle);
2470 } else {
2471 int error2;
2472
2473 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2474 value, value_len, flags);
2475 error2 = ext4_journal_stop(handle);
2476 if (error == -ENOSPC &&
2477 ext4_should_retry_alloc(sb, &retries))
2478 goto retry;
2479 if (error == 0)
2480 error = error2;
2481 }
2482 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2483
2484 return error;
2485}
2486
2487/*
2488 * Shift the EA entries in the inode to create space for the increased
2489 * i_extra_isize.
2490 */
2491static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2492 int value_offs_shift, void *to,
2493 void *from, size_t n)
2494{
2495 struct ext4_xattr_entry *last = entry;
2496 int new_offs;
2497
2498 /* We always shift xattr headers further thus offsets get lower */
2499 BUG_ON(value_offs_shift > 0);
2500
2501 /* Adjust the value offsets of the entries */
2502 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2503 if (!last->e_value_inum && last->e_value_size) {
2504 new_offs = le16_to_cpu(last->e_value_offs) +
2505 value_offs_shift;
2506 last->e_value_offs = cpu_to_le16(new_offs);
2507 }
2508 }
2509 /* Shift the entries by n bytes */
2510 memmove(to, from, n);
2511}
2512
2513/*
2514 * Move xattr pointed to by 'entry' from inode into external xattr block
2515 */
2516static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2517 struct ext4_inode *raw_inode,
2518 struct ext4_xattr_entry *entry)
2519{
2520 struct ext4_xattr_ibody_find *is = NULL;
2521 struct ext4_xattr_block_find *bs = NULL;
2522 char *buffer = NULL, *b_entry_name = NULL;
2523 size_t value_size = le32_to_cpu(entry->e_value_size);
2524 struct ext4_xattr_info i = {
2525 .value = NULL,
2526 .value_len = 0,
2527 .name_index = entry->e_name_index,
2528 .in_inode = !!entry->e_value_inum,
2529 };
2530 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2531 int error;
2532
2533 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2534 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2535 buffer = kmalloc(value_size, GFP_NOFS);
2536 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2537 if (!is || !bs || !buffer || !b_entry_name) {
2538 error = -ENOMEM;
2539 goto out;
2540 }
2541
2542 is->s.not_found = -ENODATA;
2543 bs->s.not_found = -ENODATA;
2544 is->iloc.bh = NULL;
2545 bs->bh = NULL;
2546
2547 /* Save the entry name and the entry value */
2548 if (entry->e_value_inum) {
2549 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2550 if (error)
2551 goto out;
2552 } else {
2553 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2554 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2555 }
2556
2557 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2558 b_entry_name[entry->e_name_len] = '\0';
2559 i.name = b_entry_name;
2560
2561 error = ext4_get_inode_loc(inode, &is->iloc);
2562 if (error)
2563 goto out;
2564
2565 error = ext4_xattr_ibody_find(inode, &i, is);
2566 if (error)
2567 goto out;
2568
2569 /* Remove the chosen entry from the inode */
2570 error = ext4_xattr_ibody_set(handle, inode, &i, is);
2571 if (error)
2572 goto out;
2573
2574 i.value = buffer;
2575 i.value_len = value_size;
2576 error = ext4_xattr_block_find(inode, &i, bs);
2577 if (error)
2578 goto out;
2579
2580 /* Add entry which was removed from the inode into the block */
2581 error = ext4_xattr_block_set(handle, inode, &i, bs);
2582 if (error)
2583 goto out;
2584 error = 0;
2585out:
2586 kfree(b_entry_name);
2587 kfree(buffer);
2588 if (is)
2589 brelse(is->iloc.bh);
2590 if (bs)
2591 brelse(bs->bh);
2592 kfree(is);
2593 kfree(bs);
2594
2595 return error;
2596}
2597
2598static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2599 struct ext4_inode *raw_inode,
2600 int isize_diff, size_t ifree,
2601 size_t bfree, int *total_ino)
2602{
2603 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2604 struct ext4_xattr_entry *small_entry;
2605 struct ext4_xattr_entry *entry;
2606 struct ext4_xattr_entry *last;
2607 unsigned int entry_size; /* EA entry size */
2608 unsigned int total_size; /* EA entry size + value size */
2609 unsigned int min_total_size;
2610 int error;
2611
2612 while (isize_diff > ifree) {
2613 entry = NULL;
2614 small_entry = NULL;
2615 min_total_size = ~0U;
2616 last = IFIRST(header);
2617 /* Find the entry best suited to be pushed into EA block */
2618 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2619 /* never move system.data out of the inode */
2620 if ((last->e_name_len == 4) &&
2621 (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2622 !memcmp(last->e_name, "data", 4))
2623 continue;
2624 total_size = EXT4_XATTR_LEN(last->e_name_len);
2625 if (!last->e_value_inum)
2626 total_size += EXT4_XATTR_SIZE(
2627 le32_to_cpu(last->e_value_size));
2628 if (total_size <= bfree &&
2629 total_size < min_total_size) {
2630 if (total_size + ifree < isize_diff) {
2631 small_entry = last;
2632 } else {
2633 entry = last;
2634 min_total_size = total_size;
2635 }
2636 }
2637 }
2638
2639 if (entry == NULL) {
2640 if (small_entry == NULL)
2641 return -ENOSPC;
2642 entry = small_entry;
2643 }
2644
2645 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2646 total_size = entry_size;
2647 if (!entry->e_value_inum)
2648 total_size += EXT4_XATTR_SIZE(
2649 le32_to_cpu(entry->e_value_size));
2650 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2651 entry);
2652 if (error)
2653 return error;
2654
2655 *total_ino -= entry_size;
2656 ifree += total_size;
2657 bfree -= total_size;
2658 }
2659
2660 return 0;
2661}
2662
2663/*
2664 * Expand an inode by new_extra_isize bytes when EAs are present.
2665 * Returns 0 on success or negative error number on failure.
2666 */
2667int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2668 struct ext4_inode *raw_inode, handle_t *handle)
2669{
2670 struct ext4_xattr_ibody_header *header;
2671 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2672 static unsigned int mnt_count;
2673 size_t min_offs;
2674 size_t ifree, bfree;
2675 int total_ino;
2676 void *base, *end;
2677 int error = 0, tried_min_extra_isize = 0;
2678 int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2679 int isize_diff; /* How much do we need to grow i_extra_isize */
2680
2681retry:
2682 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2683 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2684 return 0;
2685
2686 header = IHDR(inode, raw_inode);
2687
2688 /*
2689 * Check if enough free space is available in the inode to shift the
2690 * entries ahead by new_extra_isize.
2691 */
2692
2693 base = IFIRST(header);
2694 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2695 min_offs = end - base;
2696 total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2697
2698 error = xattr_check_inode(inode, header, end);
2699 if (error)
2700 goto cleanup;
2701
2702 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2703 if (ifree >= isize_diff)
2704 goto shift;
2705
2706 /*
2707 * Enough free space isn't available in the inode, check if
2708 * EA block can hold new_extra_isize bytes.
2709 */
2710 if (EXT4_I(inode)->i_file_acl) {
2711 struct buffer_head *bh;
2712
2713 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2714 if (IS_ERR(bh)) {
2715 error = PTR_ERR(bh);
2716 goto cleanup;
2717 }
2718 error = ext4_xattr_check_block(inode, bh);
2719 if (error) {
2720 brelse(bh);
2721 goto cleanup;
2722 }
2723 base = BHDR(bh);
2724 end = bh->b_data + bh->b_size;
2725 min_offs = end - base;
2726 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2727 NULL);
2728 brelse(bh);
2729 if (bfree + ifree < isize_diff) {
2730 if (!tried_min_extra_isize && s_min_extra_isize) {
2731 tried_min_extra_isize++;
2732 new_extra_isize = s_min_extra_isize;
2733 goto retry;
2734 }
2735 error = -ENOSPC;
2736 goto cleanup;
2737 }
2738 } else {
2739 bfree = inode->i_sb->s_blocksize;
2740 }
2741
2742 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2743 isize_diff, ifree, bfree,
2744 &total_ino);
2745 if (error) {
2746 if (error == -ENOSPC && !tried_min_extra_isize &&
2747 s_min_extra_isize) {
2748 tried_min_extra_isize++;
2749 new_extra_isize = s_min_extra_isize;
2750 goto retry;
2751 }
2752 goto cleanup;
2753 }
2754shift:
2755 /* Adjust the offsets and shift the remaining entries ahead */
2756 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2757 - new_extra_isize, (void *)raw_inode +
2758 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2759 (void *)header, total_ino);
2760 EXT4_I(inode)->i_extra_isize = new_extra_isize;
2761
2762cleanup:
2763 if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2764 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2765 inode->i_ino);
2766 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2767 }
2768 return error;
2769}
2770
2771#define EIA_INCR 16 /* must be 2^n */
2772#define EIA_MASK (EIA_INCR - 1)
2773
2774/* Add the large xattr @inode into @ea_inode_array for deferred iput().
2775 * If @ea_inode_array is new or full it will be grown and the old
2776 * contents copied over.
2777 */
2778static int
2779ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2780 struct inode *inode)
2781{
2782 if (*ea_inode_array == NULL) {
2783 /*
2784 * Start with 15 inodes, so it fits into a power-of-two size.
2785 * If *ea_inode_array is NULL, this is essentially offsetof()
2786 */
2787 (*ea_inode_array) =
2788 kmalloc(offsetof(struct ext4_xattr_inode_array,
2789 inodes[EIA_MASK]),
2790 GFP_NOFS);
2791 if (*ea_inode_array == NULL)
2792 return -ENOMEM;
2793 (*ea_inode_array)->count = 0;
2794 } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2795 /* expand the array once all 15 + n * 16 slots are full */
2796 struct ext4_xattr_inode_array *new_array = NULL;
2797 int count = (*ea_inode_array)->count;
2798
2799 /* if new_array is NULL, this is essentially offsetof() */
2800 new_array = kmalloc(
2801 offsetof(struct ext4_xattr_inode_array,
2802 inodes[count + EIA_INCR]),
2803 GFP_NOFS);
2804 if (new_array == NULL)
2805 return -ENOMEM;
2806 memcpy(new_array, *ea_inode_array,
2807 offsetof(struct ext4_xattr_inode_array, inodes[count]));
2808 kfree(*ea_inode_array);
2809 *ea_inode_array = new_array;
2810 }
2811 (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2812 return 0;
2813}
2814
2815/*
2816 * ext4_xattr_delete_inode()
2817 *
2818 * Free extended attribute resources associated with this inode. Traverse
2819 * all entries and decrement reference on any xattr inodes associated with this
2820 * inode. This is called immediately before an inode is freed. We have exclusive
2821 * access to the inode. If an orphan inode is deleted it will also release its
2822 * references on xattr block and xattr inodes.
2823 */
2824int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2825 struct ext4_xattr_inode_array **ea_inode_array,
2826 int extra_credits)
2827{
2828 struct buffer_head *bh = NULL;
2829 struct ext4_xattr_ibody_header *header;
2830 struct ext4_iloc iloc = { .bh = NULL };
2831 struct ext4_xattr_entry *entry;
2832 struct inode *ea_inode;
2833 int error;
2834
2835 error = ext4_journal_ensure_credits(handle, extra_credits,
2836 ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2837 if (error < 0) {
2838 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2839 goto cleanup;
2840 }
2841
2842 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2843 ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2844
2845 error = ext4_get_inode_loc(inode, &iloc);
2846 if (error) {
2847 EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2848 goto cleanup;
2849 }
2850
2851 error = ext4_journal_get_write_access(handle, iloc.bh);
2852 if (error) {
2853 EXT4_ERROR_INODE(inode, "write access (error %d)",
2854 error);
2855 goto cleanup;
2856 }
2857
2858 header = IHDR(inode, ext4_raw_inode(&iloc));
2859 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2860 ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2861 IFIRST(header),
2862 false /* block_csum */,
2863 ea_inode_array,
2864 extra_credits,
2865 false /* skip_quota */);
2866 }
2867
2868 if (EXT4_I(inode)->i_file_acl) {
2869 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2870 if (IS_ERR(bh)) {
2871 error = PTR_ERR(bh);
2872 if (error == -EIO) {
2873 EXT4_ERROR_INODE_ERR(inode, EIO,
2874 "block %llu read error",
2875 EXT4_I(inode)->i_file_acl);
2876 }
2877 bh = NULL;
2878 goto cleanup;
2879 }
2880 error = ext4_xattr_check_block(inode, bh);
2881 if (error)
2882 goto cleanup;
2883
2884 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2885 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2886 entry = EXT4_XATTR_NEXT(entry)) {
2887 if (!entry->e_value_inum)
2888 continue;
2889 error = ext4_xattr_inode_iget(inode,
2890 le32_to_cpu(entry->e_value_inum),
2891 le32_to_cpu(entry->e_hash),
2892 &ea_inode);
2893 if (error)
2894 continue;
2895 ext4_xattr_inode_free_quota(inode, ea_inode,
2896 le32_to_cpu(entry->e_value_size));
2897 iput(ea_inode);
2898 }
2899
2900 }
2901
2902 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2903 extra_credits);
2904 /*
2905 * Update i_file_acl value in the same transaction that releases
2906 * block.
2907 */
2908 EXT4_I(inode)->i_file_acl = 0;
2909 error = ext4_mark_inode_dirty(handle, inode);
2910 if (error) {
2911 EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2912 error);
2913 goto cleanup;
2914 }
2915 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2916 }
2917 error = 0;
2918cleanup:
2919 brelse(iloc.bh);
2920 brelse(bh);
2921 return error;
2922}
2923
2924void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2925{
2926 int idx;
2927
2928 if (ea_inode_array == NULL)
2929 return;
2930
2931 for (idx = 0; idx < ea_inode_array->count; ++idx)
2932 iput(ea_inode_array->inodes[idx]);
2933 kfree(ea_inode_array);
2934}
2935
2936/*
2937 * ext4_xattr_block_cache_insert()
2938 *
2939 * Create a new entry in the extended attribute block cache, and insert
2940 * it unless such an entry is already in the cache.
2941 *
2942 * Returns 0, or a negative error number on failure.
2943 */
2944static void
2945ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2946 struct buffer_head *bh)
2947{
2948 struct ext4_xattr_header *header = BHDR(bh);
2949 __u32 hash = le32_to_cpu(header->h_hash);
2950 int reusable = le32_to_cpu(header->h_refcount) <
2951 EXT4_XATTR_REFCOUNT_MAX;
2952 int error;
2953
2954 if (!ea_block_cache)
2955 return;
2956 error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2957 bh->b_blocknr, reusable);
2958 if (error) {
2959 if (error == -EBUSY)
2960 ea_bdebug(bh, "already in cache");
2961 } else
2962 ea_bdebug(bh, "inserting [%x]", (int)hash);
2963}
2964
2965/*
2966 * ext4_xattr_cmp()
2967 *
2968 * Compare two extended attribute blocks for equality.
2969 *
2970 * Returns 0 if the blocks are equal, 1 if they differ, and
2971 * a negative error number on errors.
2972 */
2973static int
2974ext4_xattr_cmp(struct ext4_xattr_header *header1,
2975 struct ext4_xattr_header *header2)
2976{
2977 struct ext4_xattr_entry *entry1, *entry2;
2978
2979 entry1 = ENTRY(header1+1);
2980 entry2 = ENTRY(header2+1);
2981 while (!IS_LAST_ENTRY(entry1)) {
2982 if (IS_LAST_ENTRY(entry2))
2983 return 1;
2984 if (entry1->e_hash != entry2->e_hash ||
2985 entry1->e_name_index != entry2->e_name_index ||
2986 entry1->e_name_len != entry2->e_name_len ||
2987 entry1->e_value_size != entry2->e_value_size ||
2988 entry1->e_value_inum != entry2->e_value_inum ||
2989 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
2990 return 1;
2991 if (!entry1->e_value_inum &&
2992 memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
2993 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
2994 le32_to_cpu(entry1->e_value_size)))
2995 return 1;
2996
2997 entry1 = EXT4_XATTR_NEXT(entry1);
2998 entry2 = EXT4_XATTR_NEXT(entry2);
2999 }
3000 if (!IS_LAST_ENTRY(entry2))
3001 return 1;
3002 return 0;
3003}
3004
3005/*
3006 * ext4_xattr_block_cache_find()
3007 *
3008 * Find an identical extended attribute block.
3009 *
3010 * Returns a pointer to the block found, or NULL if such a block was
3011 * not found or an error occurred.
3012 */
3013static struct buffer_head *
3014ext4_xattr_block_cache_find(struct inode *inode,
3015 struct ext4_xattr_header *header,
3016 struct mb_cache_entry **pce)
3017{
3018 __u32 hash = le32_to_cpu(header->h_hash);
3019 struct mb_cache_entry *ce;
3020 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3021
3022 if (!ea_block_cache)
3023 return NULL;
3024 if (!header->h_hash)
3025 return NULL; /* never share */
3026 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3027 ce = mb_cache_entry_find_first(ea_block_cache, hash);
3028 while (ce) {
3029 struct buffer_head *bh;
3030
3031 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3032 if (IS_ERR(bh)) {
3033 if (PTR_ERR(bh) == -ENOMEM)
3034 return NULL;
3035 bh = NULL;
3036 EXT4_ERROR_INODE(inode, "block %lu read error",
3037 (unsigned long)ce->e_value);
3038 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3039 *pce = ce;
3040 return bh;
3041 }
3042 brelse(bh);
3043 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3044 }
3045 return NULL;
3046}
3047
3048#define NAME_HASH_SHIFT 5
3049#define VALUE_HASH_SHIFT 16
3050
3051/*
3052 * ext4_xattr_hash_entry()
3053 *
3054 * Compute the hash of an extended attribute.
3055 */
3056static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3057 size_t value_count)
3058{
3059 __u32 hash = 0;
3060
3061 while (name_len--) {
3062 hash = (hash << NAME_HASH_SHIFT) ^
3063 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3064 *name++;
3065 }
3066 while (value_count--) {
3067 hash = (hash << VALUE_HASH_SHIFT) ^
3068 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3069 le32_to_cpu(*value++);
3070 }
3071 return cpu_to_le32(hash);
3072}
3073
3074#undef NAME_HASH_SHIFT
3075#undef VALUE_HASH_SHIFT
3076
3077#define BLOCK_HASH_SHIFT 16
3078
3079/*
3080 * ext4_xattr_rehash()
3081 *
3082 * Re-compute the extended attribute hash value after an entry has changed.
3083 */
3084static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3085{
3086 struct ext4_xattr_entry *here;
3087 __u32 hash = 0;
3088
3089 here = ENTRY(header+1);
3090 while (!IS_LAST_ENTRY(here)) {
3091 if (!here->e_hash) {
3092 /* Block is not shared if an entry's hash value == 0 */
3093 hash = 0;
3094 break;
3095 }
3096 hash = (hash << BLOCK_HASH_SHIFT) ^
3097 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3098 le32_to_cpu(here->e_hash);
3099 here = EXT4_XATTR_NEXT(here);
3100 }
3101 header->h_hash = cpu_to_le32(hash);
3102}
3103
3104#undef BLOCK_HASH_SHIFT
3105
3106#define HASH_BUCKET_BITS 10
3107
3108struct mb_cache *
3109ext4_xattr_create_cache(void)
3110{
3111 return mb_cache_create(HASH_BUCKET_BITS);
3112}
3113
3114void ext4_xattr_destroy_cache(struct mb_cache *cache)
3115{
3116 if (cache)
3117 mb_cache_destroy(cache);
3118}
3119