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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 ext4_set_feature_xattr(sb);
796 ext4_handle_dirty_super(handle, sb);
797 }
798}
799
800int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
801{
802 struct ext4_iloc iloc = { .bh = NULL };
803 struct buffer_head *bh = NULL;
804 struct ext4_inode *raw_inode;
805 struct ext4_xattr_ibody_header *header;
806 struct ext4_xattr_entry *entry;
807 qsize_t ea_inode_refs = 0;
808 void *end;
809 int ret;
810
811 lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
812
813 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
814 ret = ext4_get_inode_loc(inode, &iloc);
815 if (ret)
816 goto out;
817 raw_inode = ext4_raw_inode(&iloc);
818 header = IHDR(inode, raw_inode);
819 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
820 ret = xattr_check_inode(inode, header, end);
821 if (ret)
822 goto out;
823
824 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
825 entry = EXT4_XATTR_NEXT(entry))
826 if (entry->e_value_inum)
827 ea_inode_refs++;
828 }
829
830 if (EXT4_I(inode)->i_file_acl) {
831 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
832 if (IS_ERR(bh)) {
833 ret = PTR_ERR(bh);
834 bh = NULL;
835 goto out;
836 }
837
838 ret = ext4_xattr_check_block(inode, bh);
839 if (ret)
840 goto out;
841
842 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
843 entry = EXT4_XATTR_NEXT(entry))
844 if (entry->e_value_inum)
845 ea_inode_refs++;
846 }
847 *usage = ea_inode_refs + 1;
848 ret = 0;
849out:
850 brelse(iloc.bh);
851 brelse(bh);
852 return ret;
853}
854
855static inline size_t round_up_cluster(struct inode *inode, size_t length)
856{
857 struct super_block *sb = inode->i_sb;
858 size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
859 inode->i_blkbits);
860 size_t mask = ~(cluster_size - 1);
861
862 return (length + cluster_size - 1) & mask;
863}
864
865static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
866{
867 int err;
868
869 err = dquot_alloc_inode(inode);
870 if (err)
871 return err;
872 err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
873 if (err)
874 dquot_free_inode(inode);
875 return err;
876}
877
878static void ext4_xattr_inode_free_quota(struct inode *parent,
879 struct inode *ea_inode,
880 size_t len)
881{
882 if (ea_inode &&
883 ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
884 return;
885 dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
886 dquot_free_inode(parent);
887}
888
889int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
890 struct buffer_head *block_bh, size_t value_len,
891 bool is_create)
892{
893 int credits;
894 int blocks;
895
896 /*
897 * 1) Owner inode update
898 * 2) Ref count update on old xattr block
899 * 3) new xattr block
900 * 4) block bitmap update for new xattr block
901 * 5) group descriptor for new xattr block
902 * 6) block bitmap update for old xattr block
903 * 7) group descriptor for old block
904 *
905 * 6 & 7 can happen if we have two racing threads T_a and T_b
906 * which are each trying to set an xattr on inodes I_a and I_b
907 * which were both initially sharing an xattr block.
908 */
909 credits = 7;
910
911 /* Quota updates. */
912 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
913
914 /*
915 * In case of inline data, we may push out the data to a block,
916 * so we need to reserve credits for this eventuality
917 */
918 if (inode && ext4_has_inline_data(inode))
919 credits += ext4_writepage_trans_blocks(inode) + 1;
920
921 /* We are done if ea_inode feature is not enabled. */
922 if (!ext4_has_feature_ea_inode(sb))
923 return credits;
924
925 /* New ea_inode, inode map, block bitmap, group descriptor. */
926 credits += 4;
927
928 /* Data blocks. */
929 blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
930
931 /* Indirection block or one level of extent tree. */
932 blocks += 1;
933
934 /* Block bitmap and group descriptor updates for each block. */
935 credits += blocks * 2;
936
937 /* Blocks themselves. */
938 credits += blocks;
939
940 if (!is_create) {
941 /* Dereference ea_inode holding old xattr value.
942 * Old ea_inode, inode map, block bitmap, group descriptor.
943 */
944 credits += 4;
945
946 /* Data blocks for old ea_inode. */
947 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
948
949 /* Indirection block or one level of extent tree for old
950 * ea_inode.
951 */
952 blocks += 1;
953
954 /* Block bitmap and group descriptor updates for each block. */
955 credits += blocks * 2;
956 }
957
958 /* We may need to clone the existing xattr block in which case we need
959 * to increment ref counts for existing ea_inodes referenced by it.
960 */
961 if (block_bh) {
962 struct ext4_xattr_entry *entry = BFIRST(block_bh);
963
964 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
965 if (entry->e_value_inum)
966 /* Ref count update on ea_inode. */
967 credits += 1;
968 }
969 return credits;
970}
971
972static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
973 int ref_change)
974{
975 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
976 struct ext4_iloc iloc;
977 s64 ref_count;
978 u32 hash;
979 int ret;
980
981 inode_lock(ea_inode);
982
983 ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
984 if (ret)
985 goto out;
986
987 ref_count = ext4_xattr_inode_get_ref(ea_inode);
988 ref_count += ref_change;
989 ext4_xattr_inode_set_ref(ea_inode, ref_count);
990
991 if (ref_change > 0) {
992 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
993 ea_inode->i_ino, ref_count);
994
995 if (ref_count == 1) {
996 WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
997 ea_inode->i_ino, ea_inode->i_nlink);
998
999 set_nlink(ea_inode, 1);
1000 ext4_orphan_del(handle, ea_inode);
1001
1002 if (ea_inode_cache) {
1003 hash = ext4_xattr_inode_get_hash(ea_inode);
1004 mb_cache_entry_create(ea_inode_cache,
1005 GFP_NOFS, hash,
1006 ea_inode->i_ino,
1007 true /* reusable */);
1008 }
1009 }
1010 } else {
1011 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1012 ea_inode->i_ino, ref_count);
1013
1014 if (ref_count == 0) {
1015 WARN_ONCE(ea_inode->i_nlink != 1,
1016 "EA inode %lu i_nlink=%u",
1017 ea_inode->i_ino, ea_inode->i_nlink);
1018
1019 clear_nlink(ea_inode);
1020 ext4_orphan_add(handle, ea_inode);
1021
1022 if (ea_inode_cache) {
1023 hash = ext4_xattr_inode_get_hash(ea_inode);
1024 mb_cache_entry_delete(ea_inode_cache, hash,
1025 ea_inode->i_ino);
1026 }
1027 }
1028 }
1029
1030 ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1031 if (ret)
1032 ext4_warning_inode(ea_inode,
1033 "ext4_mark_iloc_dirty() failed ret=%d", ret);
1034out:
1035 inode_unlock(ea_inode);
1036 return ret;
1037}
1038
1039static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1040{
1041 return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1042}
1043
1044static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1045{
1046 return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1047}
1048
1049static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1050 struct ext4_xattr_entry *first)
1051{
1052 struct inode *ea_inode;
1053 struct ext4_xattr_entry *entry;
1054 struct ext4_xattr_entry *failed_entry;
1055 unsigned int ea_ino;
1056 int err, saved_err;
1057
1058 for (entry = first; !IS_LAST_ENTRY(entry);
1059 entry = EXT4_XATTR_NEXT(entry)) {
1060 if (!entry->e_value_inum)
1061 continue;
1062 ea_ino = le32_to_cpu(entry->e_value_inum);
1063 err = ext4_xattr_inode_iget(parent, ea_ino,
1064 le32_to_cpu(entry->e_hash),
1065 &ea_inode);
1066 if (err)
1067 goto cleanup;
1068 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1069 if (err) {
1070 ext4_warning_inode(ea_inode, "inc ref error %d", err);
1071 iput(ea_inode);
1072 goto cleanup;
1073 }
1074 iput(ea_inode);
1075 }
1076 return 0;
1077
1078cleanup:
1079 saved_err = err;
1080 failed_entry = entry;
1081
1082 for (entry = first; entry != failed_entry;
1083 entry = EXT4_XATTR_NEXT(entry)) {
1084 if (!entry->e_value_inum)
1085 continue;
1086 ea_ino = le32_to_cpu(entry->e_value_inum);
1087 err = ext4_xattr_inode_iget(parent, ea_ino,
1088 le32_to_cpu(entry->e_hash),
1089 &ea_inode);
1090 if (err) {
1091 ext4_warning(parent->i_sb,
1092 "cleanup ea_ino %u iget error %d", ea_ino,
1093 err);
1094 continue;
1095 }
1096 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1097 if (err)
1098 ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1099 err);
1100 iput(ea_inode);
1101 }
1102 return saved_err;
1103}
1104
1105static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1106 struct buffer_head *bh, bool block_csum, bool dirty)
1107{
1108 int error;
1109
1110 if (bh && dirty) {
1111 if (block_csum)
1112 ext4_xattr_block_csum_set(inode, bh);
1113 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1114 if (error) {
1115 ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1116 error);
1117 return error;
1118 }
1119 }
1120 return 0;
1121}
1122
1123static void
1124ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1125 struct buffer_head *bh,
1126 struct ext4_xattr_entry *first, bool block_csum,
1127 struct ext4_xattr_inode_array **ea_inode_array,
1128 int extra_credits, bool skip_quota)
1129{
1130 struct inode *ea_inode;
1131 struct ext4_xattr_entry *entry;
1132 bool dirty = false;
1133 unsigned int ea_ino;
1134 int err;
1135 int credits;
1136
1137 /* One credit for dec ref on ea_inode, one for orphan list addition, */
1138 credits = 2 + extra_credits;
1139
1140 for (entry = first; !IS_LAST_ENTRY(entry);
1141 entry = EXT4_XATTR_NEXT(entry)) {
1142 if (!entry->e_value_inum)
1143 continue;
1144 ea_ino = le32_to_cpu(entry->e_value_inum);
1145 err = ext4_xattr_inode_iget(parent, ea_ino,
1146 le32_to_cpu(entry->e_hash),
1147 &ea_inode);
1148 if (err)
1149 continue;
1150
1151 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1152 if (err) {
1153 ext4_warning_inode(ea_inode,
1154 "Expand inode array err=%d", err);
1155 iput(ea_inode);
1156 continue;
1157 }
1158
1159 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1160 ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1161 ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1162 dirty));
1163 if (err < 0) {
1164 ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1165 err);
1166 continue;
1167 }
1168 if (err > 0) {
1169 err = ext4_journal_get_write_access(handle, bh);
1170 if (err) {
1171 ext4_warning_inode(ea_inode,
1172 "Re-get write access err=%d",
1173 err);
1174 continue;
1175 }
1176 }
1177
1178 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1179 if (err) {
1180 ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1181 err);
1182 continue;
1183 }
1184
1185 if (!skip_quota)
1186 ext4_xattr_inode_free_quota(parent, ea_inode,
1187 le32_to_cpu(entry->e_value_size));
1188
1189 /*
1190 * Forget about ea_inode within the same transaction that
1191 * decrements the ref count. This avoids duplicate decrements in
1192 * case the rest of the work spills over to subsequent
1193 * transactions.
1194 */
1195 entry->e_value_inum = 0;
1196 entry->e_value_size = 0;
1197
1198 dirty = true;
1199 }
1200
1201 if (dirty) {
1202 /*
1203 * Note that we are deliberately skipping csum calculation for
1204 * the final update because we do not expect any journal
1205 * restarts until xattr block is freed.
1206 */
1207
1208 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1209 if (err)
1210 ext4_warning_inode(parent,
1211 "handle dirty metadata err=%d", err);
1212 }
1213}
1214
1215/*
1216 * Release the xattr block BH: If the reference count is > 1, decrement it;
1217 * otherwise free the block.
1218 */
1219static void
1220ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1221 struct buffer_head *bh,
1222 struct ext4_xattr_inode_array **ea_inode_array,
1223 int extra_credits)
1224{
1225 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1226 u32 hash, ref;
1227 int error = 0;
1228
1229 BUFFER_TRACE(bh, "get_write_access");
1230 error = ext4_journal_get_write_access(handle, bh);
1231 if (error)
1232 goto out;
1233
1234 lock_buffer(bh);
1235 hash = le32_to_cpu(BHDR(bh)->h_hash);
1236 ref = le32_to_cpu(BHDR(bh)->h_refcount);
1237 if (ref == 1) {
1238 ea_bdebug(bh, "refcount now=0; freeing");
1239 /*
1240 * This must happen under buffer lock for
1241 * ext4_xattr_block_set() to reliably detect freed block
1242 */
1243 if (ea_block_cache)
1244 mb_cache_entry_delete(ea_block_cache, hash,
1245 bh->b_blocknr);
1246 get_bh(bh);
1247 unlock_buffer(bh);
1248
1249 if (ext4_has_feature_ea_inode(inode->i_sb))
1250 ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1251 BFIRST(bh),
1252 true /* block_csum */,
1253 ea_inode_array,
1254 extra_credits,
1255 true /* skip_quota */);
1256 ext4_free_blocks(handle, inode, bh, 0, 1,
1257 EXT4_FREE_BLOCKS_METADATA |
1258 EXT4_FREE_BLOCKS_FORGET);
1259 } else {
1260 ref--;
1261 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1262 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1263 struct mb_cache_entry *ce;
1264
1265 if (ea_block_cache) {
1266 ce = mb_cache_entry_get(ea_block_cache, hash,
1267 bh->b_blocknr);
1268 if (ce) {
1269 ce->e_reusable = 1;
1270 mb_cache_entry_put(ea_block_cache, ce);
1271 }
1272 }
1273 }
1274
1275 ext4_xattr_block_csum_set(inode, bh);
1276 /*
1277 * Beware of this ugliness: Releasing of xattr block references
1278 * from different inodes can race and so we have to protect
1279 * from a race where someone else frees the block (and releases
1280 * its journal_head) before we are done dirtying the buffer. In
1281 * nojournal mode this race is harmless and we actually cannot
1282 * call ext4_handle_dirty_metadata() with locked buffer as
1283 * that function can call sync_dirty_buffer() so for that case
1284 * we handle the dirtying after unlocking the buffer.
1285 */
1286 if (ext4_handle_valid(handle))
1287 error = ext4_handle_dirty_metadata(handle, inode, bh);
1288 unlock_buffer(bh);
1289 if (!ext4_handle_valid(handle))
1290 error = ext4_handle_dirty_metadata(handle, inode, bh);
1291 if (IS_SYNC(inode))
1292 ext4_handle_sync(handle);
1293 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1294 ea_bdebug(bh, "refcount now=%d; releasing",
1295 le32_to_cpu(BHDR(bh)->h_refcount));
1296 }
1297out:
1298 ext4_std_error(inode->i_sb, error);
1299 return;
1300}
1301
1302/*
1303 * Find the available free space for EAs. This also returns the total number of
1304 * bytes used by EA entries.
1305 */
1306static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1307 size_t *min_offs, void *base, int *total)
1308{
1309 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1310 if (!last->e_value_inum && last->e_value_size) {
1311 size_t offs = le16_to_cpu(last->e_value_offs);
1312 if (offs < *min_offs)
1313 *min_offs = offs;
1314 }
1315 if (total)
1316 *total += EXT4_XATTR_LEN(last->e_name_len);
1317 }
1318 return (*min_offs - ((void *)last - base) - sizeof(__u32));
1319}
1320
1321/*
1322 * Write the value of the EA in an inode.
1323 */
1324static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1325 const void *buf, int bufsize)
1326{
1327 struct buffer_head *bh = NULL;
1328 unsigned long block = 0;
1329 int blocksize = ea_inode->i_sb->s_blocksize;
1330 int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1331 int csize, wsize = 0;
1332 int ret = 0, ret2 = 0;
1333 int retries = 0;
1334
1335retry:
1336 while (ret >= 0 && ret < max_blocks) {
1337 struct ext4_map_blocks map;
1338 map.m_lblk = block += ret;
1339 map.m_len = max_blocks -= ret;
1340
1341 ret = ext4_map_blocks(handle, ea_inode, &map,
1342 EXT4_GET_BLOCKS_CREATE);
1343 if (ret <= 0) {
1344 ext4_mark_inode_dirty(handle, ea_inode);
1345 if (ret == -ENOSPC &&
1346 ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1347 ret = 0;
1348 goto retry;
1349 }
1350 break;
1351 }
1352 }
1353
1354 if (ret < 0)
1355 return ret;
1356
1357 block = 0;
1358 while (wsize < bufsize) {
1359 brelse(bh);
1360 csize = (bufsize - wsize) > blocksize ? blocksize :
1361 bufsize - wsize;
1362 bh = ext4_getblk(handle, ea_inode, block, 0);
1363 if (IS_ERR(bh))
1364 return PTR_ERR(bh);
1365 if (!bh) {
1366 WARN_ON_ONCE(1);
1367 EXT4_ERROR_INODE(ea_inode,
1368 "ext4_getblk() return bh = NULL");
1369 return -EFSCORRUPTED;
1370 }
1371 ret = ext4_journal_get_write_access(handle, bh);
1372 if (ret)
1373 goto out;
1374
1375 memcpy(bh->b_data, buf, csize);
1376 set_buffer_uptodate(bh);
1377 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1378
1379 buf += csize;
1380 wsize += csize;
1381 block += 1;
1382 }
1383
1384 inode_lock(ea_inode);
1385 i_size_write(ea_inode, wsize);
1386 ext4_update_i_disksize(ea_inode, wsize);
1387 inode_unlock(ea_inode);
1388
1389 ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1390 if (unlikely(ret2 && !ret))
1391 ret = ret2;
1392
1393out:
1394 brelse(bh);
1395
1396 return ret;
1397}
1398
1399/*
1400 * Create an inode to store the value of a large EA.
1401 */
1402static struct inode *ext4_xattr_inode_create(handle_t *handle,
1403 struct inode *inode, u32 hash)
1404{
1405 struct inode *ea_inode = NULL;
1406 uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1407 int err;
1408
1409 /*
1410 * Let the next inode be the goal, so we try and allocate the EA inode
1411 * in the same group, or nearby one.
1412 */
1413 ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1414 S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1415 EXT4_EA_INODE_FL);
1416 if (!IS_ERR(ea_inode)) {
1417 ea_inode->i_op = &ext4_file_inode_operations;
1418 ea_inode->i_fop = &ext4_file_operations;
1419 ext4_set_aops(ea_inode);
1420 ext4_xattr_inode_set_class(ea_inode);
1421 unlock_new_inode(ea_inode);
1422 ext4_xattr_inode_set_ref(ea_inode, 1);
1423 ext4_xattr_inode_set_hash(ea_inode, hash);
1424 err = ext4_mark_inode_dirty(handle, ea_inode);
1425 if (!err)
1426 err = ext4_inode_attach_jinode(ea_inode);
1427 if (err) {
1428 iput(ea_inode);
1429 return ERR_PTR(err);
1430 }
1431
1432 /*
1433 * Xattr inodes are shared therefore quota charging is performed
1434 * at a higher level.
1435 */
1436 dquot_free_inode(ea_inode);
1437 dquot_drop(ea_inode);
1438 inode_lock(ea_inode);
1439 ea_inode->i_flags |= S_NOQUOTA;
1440 inode_unlock(ea_inode);
1441 }
1442
1443 return ea_inode;
1444}
1445
1446static struct inode *
1447ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1448 size_t value_len, u32 hash)
1449{
1450 struct inode *ea_inode;
1451 struct mb_cache_entry *ce;
1452 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1453 void *ea_data;
1454
1455 if (!ea_inode_cache)
1456 return NULL;
1457
1458 ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1459 if (!ce)
1460 return NULL;
1461
1462 ea_data = kvmalloc(value_len, GFP_KERNEL);
1463 if (!ea_data) {
1464 mb_cache_entry_put(ea_inode_cache, ce);
1465 return NULL;
1466 }
1467
1468 while (ce) {
1469 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1470 EXT4_IGET_NORMAL);
1471 if (!IS_ERR(ea_inode) &&
1472 !is_bad_inode(ea_inode) &&
1473 (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1474 i_size_read(ea_inode) == value_len &&
1475 !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1476 !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1477 value_len) &&
1478 !memcmp(value, ea_data, value_len)) {
1479 mb_cache_entry_touch(ea_inode_cache, ce);
1480 mb_cache_entry_put(ea_inode_cache, ce);
1481 kvfree(ea_data);
1482 return ea_inode;
1483 }
1484
1485 if (!IS_ERR(ea_inode))
1486 iput(ea_inode);
1487 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1488 }
1489 kvfree(ea_data);
1490 return NULL;
1491}
1492
1493/*
1494 * Add value of the EA in an inode.
1495 */
1496static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1497 const void *value, size_t value_len,
1498 struct inode **ret_inode)
1499{
1500 struct inode *ea_inode;
1501 u32 hash;
1502 int err;
1503
1504 hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1505 ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1506 if (ea_inode) {
1507 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1508 if (err) {
1509 iput(ea_inode);
1510 return err;
1511 }
1512
1513 *ret_inode = ea_inode;
1514 return 0;
1515 }
1516
1517 /* Create an inode for the EA value */
1518 ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1519 if (IS_ERR(ea_inode))
1520 return PTR_ERR(ea_inode);
1521
1522 err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1523 if (err) {
1524 ext4_xattr_inode_dec_ref(handle, ea_inode);
1525 iput(ea_inode);
1526 return err;
1527 }
1528
1529 if (EA_INODE_CACHE(inode))
1530 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1531 ea_inode->i_ino, true /* reusable */);
1532
1533 *ret_inode = ea_inode;
1534 return 0;
1535}
1536
1537/*
1538 * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1539 * feature is enabled.
1540 */
1541#define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1542
1543static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1544 struct ext4_xattr_search *s,
1545 handle_t *handle, struct inode *inode,
1546 bool is_block)
1547{
1548 struct ext4_xattr_entry *last, *next;
1549 struct ext4_xattr_entry *here = s->here;
1550 size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1551 int in_inode = i->in_inode;
1552 struct inode *old_ea_inode = NULL;
1553 struct inode *new_ea_inode = NULL;
1554 size_t old_size, new_size;
1555 int ret;
1556
1557 /* Space used by old and new values. */
1558 old_size = (!s->not_found && !here->e_value_inum) ?
1559 EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1560 new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1561
1562 /*
1563 * Optimization for the simple case when old and new values have the
1564 * same padded sizes. Not applicable if external inodes are involved.
1565 */
1566 if (new_size && new_size == old_size) {
1567 size_t offs = le16_to_cpu(here->e_value_offs);
1568 void *val = s->base + offs;
1569
1570 here->e_value_size = cpu_to_le32(i->value_len);
1571 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1572 memset(val, 0, new_size);
1573 } else {
1574 memcpy(val, i->value, i->value_len);
1575 /* Clear padding bytes. */
1576 memset(val + i->value_len, 0, new_size - i->value_len);
1577 }
1578 goto update_hash;
1579 }
1580
1581 /* Compute min_offs and last. */
1582 last = s->first;
1583 for (; !IS_LAST_ENTRY(last); last = next) {
1584 next = EXT4_XATTR_NEXT(last);
1585 if ((void *)next >= s->end) {
1586 EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1587 ret = -EFSCORRUPTED;
1588 goto out;
1589 }
1590 if (!last->e_value_inum && last->e_value_size) {
1591 size_t offs = le16_to_cpu(last->e_value_offs);
1592 if (offs < min_offs)
1593 min_offs = offs;
1594 }
1595 }
1596
1597 /* Check whether we have enough space. */
1598 if (i->value) {
1599 size_t free;
1600
1601 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1602 if (!s->not_found)
1603 free += EXT4_XATTR_LEN(name_len) + old_size;
1604
1605 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1606 ret = -ENOSPC;
1607 goto out;
1608 }
1609
1610 /*
1611 * If storing the value in an external inode is an option,
1612 * reserve space for xattr entries/names in the external
1613 * attribute block so that a long value does not occupy the
1614 * whole space and prevent futher entries being added.
1615 */
1616 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1617 new_size && is_block &&
1618 (min_offs + old_size - new_size) <
1619 EXT4_XATTR_BLOCK_RESERVE(inode)) {
1620 ret = -ENOSPC;
1621 goto out;
1622 }
1623 }
1624
1625 /*
1626 * Getting access to old and new ea inodes is subject to failures.
1627 * Finish that work before doing any modifications to the xattr data.
1628 */
1629 if (!s->not_found && here->e_value_inum) {
1630 ret = ext4_xattr_inode_iget(inode,
1631 le32_to_cpu(here->e_value_inum),
1632 le32_to_cpu(here->e_hash),
1633 &old_ea_inode);
1634 if (ret) {
1635 old_ea_inode = NULL;
1636 goto out;
1637 }
1638 }
1639 if (i->value && in_inode) {
1640 WARN_ON_ONCE(!i->value_len);
1641
1642 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1643 if (ret)
1644 goto out;
1645
1646 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1647 i->value_len,
1648 &new_ea_inode);
1649 if (ret) {
1650 new_ea_inode = NULL;
1651 ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1652 goto out;
1653 }
1654 }
1655
1656 if (old_ea_inode) {
1657 /* We are ready to release ref count on the old_ea_inode. */
1658 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1659 if (ret) {
1660 /* Release newly required ref count on new_ea_inode. */
1661 if (new_ea_inode) {
1662 int err;
1663
1664 err = ext4_xattr_inode_dec_ref(handle,
1665 new_ea_inode);
1666 if (err)
1667 ext4_warning_inode(new_ea_inode,
1668 "dec ref new_ea_inode err=%d",
1669 err);
1670 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1671 i->value_len);
1672 }
1673 goto out;
1674 }
1675
1676 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1677 le32_to_cpu(here->e_value_size));
1678 }
1679
1680 /* No failures allowed past this point. */
1681
1682 if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1683 /* Remove the old value. */
1684 void *first_val = s->base + min_offs;
1685 size_t offs = le16_to_cpu(here->e_value_offs);
1686 void *val = s->base + offs;
1687
1688 memmove(first_val + old_size, first_val, val - first_val);
1689 memset(first_val, 0, old_size);
1690 min_offs += old_size;
1691
1692 /* Adjust all value offsets. */
1693 last = s->first;
1694 while (!IS_LAST_ENTRY(last)) {
1695 size_t o = le16_to_cpu(last->e_value_offs);
1696
1697 if (!last->e_value_inum &&
1698 last->e_value_size && o < offs)
1699 last->e_value_offs = cpu_to_le16(o + old_size);
1700 last = EXT4_XATTR_NEXT(last);
1701 }
1702 }
1703
1704 if (!i->value) {
1705 /* Remove old name. */
1706 size_t size = EXT4_XATTR_LEN(name_len);
1707
1708 last = ENTRY((void *)last - size);
1709 memmove(here, (void *)here + size,
1710 (void *)last - (void *)here + sizeof(__u32));
1711 memset(last, 0, size);
1712 } else if (s->not_found) {
1713 /* Insert new name. */
1714 size_t size = EXT4_XATTR_LEN(name_len);
1715 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1716
1717 memmove((void *)here + size, here, rest);
1718 memset(here, 0, size);
1719 here->e_name_index = i->name_index;
1720 here->e_name_len = name_len;
1721 memcpy(here->e_name, i->name, name_len);
1722 } else {
1723 /* This is an update, reset value info. */
1724 here->e_value_inum = 0;
1725 here->e_value_offs = 0;
1726 here->e_value_size = 0;
1727 }
1728
1729 if (i->value) {
1730 /* Insert new value. */
1731 if (in_inode) {
1732 here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1733 } else if (i->value_len) {
1734 void *val = s->base + min_offs - new_size;
1735
1736 here->e_value_offs = cpu_to_le16(min_offs - new_size);
1737 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1738 memset(val, 0, new_size);
1739 } else {
1740 memcpy(val, i->value, i->value_len);
1741 /* Clear padding bytes. */
1742 memset(val + i->value_len, 0,
1743 new_size - i->value_len);
1744 }
1745 }
1746 here->e_value_size = cpu_to_le32(i->value_len);
1747 }
1748
1749update_hash:
1750 if (i->value) {
1751 __le32 hash = 0;
1752
1753 /* Entry hash calculation. */
1754 if (in_inode) {
1755 __le32 crc32c_hash;
1756
1757 /*
1758 * Feed crc32c hash instead of the raw value for entry
1759 * hash calculation. This is to avoid walking
1760 * potentially long value buffer again.
1761 */
1762 crc32c_hash = cpu_to_le32(
1763 ext4_xattr_inode_get_hash(new_ea_inode));
1764 hash = ext4_xattr_hash_entry(here->e_name,
1765 here->e_name_len,
1766 &crc32c_hash, 1);
1767 } else if (is_block) {
1768 __le32 *value = s->base + le16_to_cpu(
1769 here->e_value_offs);
1770
1771 hash = ext4_xattr_hash_entry(here->e_name,
1772 here->e_name_len, value,
1773 new_size >> 2);
1774 }
1775 here->e_hash = hash;
1776 }
1777
1778 if (is_block)
1779 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1780
1781 ret = 0;
1782out:
1783 iput(old_ea_inode);
1784 iput(new_ea_inode);
1785 return ret;
1786}
1787
1788struct ext4_xattr_block_find {
1789 struct ext4_xattr_search s;
1790 struct buffer_head *bh;
1791};
1792
1793static int
1794ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1795 struct ext4_xattr_block_find *bs)
1796{
1797 struct super_block *sb = inode->i_sb;
1798 int error;
1799
1800 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1801 i->name_index, i->name, i->value, (long)i->value_len);
1802
1803 if (EXT4_I(inode)->i_file_acl) {
1804 /* The inode already has an extended attribute block. */
1805 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1806 if (IS_ERR(bs->bh)) {
1807 error = PTR_ERR(bs->bh);
1808 bs->bh = NULL;
1809 return error;
1810 }
1811 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1812 atomic_read(&(bs->bh->b_count)),
1813 le32_to_cpu(BHDR(bs->bh)->h_refcount));
1814 error = ext4_xattr_check_block(inode, bs->bh);
1815 if (error)
1816 return error;
1817 /* Find the named attribute. */
1818 bs->s.base = BHDR(bs->bh);
1819 bs->s.first = BFIRST(bs->bh);
1820 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1821 bs->s.here = bs->s.first;
1822 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1823 i->name_index, i->name, 1);
1824 if (error && error != -ENODATA)
1825 return error;
1826 bs->s.not_found = error;
1827 }
1828 return 0;
1829}
1830
1831static int
1832ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1833 struct ext4_xattr_info *i,
1834 struct ext4_xattr_block_find *bs)
1835{
1836 struct super_block *sb = inode->i_sb;
1837 struct buffer_head *new_bh = NULL;
1838 struct ext4_xattr_search s_copy = bs->s;
1839 struct ext4_xattr_search *s = &s_copy;
1840 struct mb_cache_entry *ce = NULL;
1841 int error = 0;
1842 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1843 struct inode *ea_inode = NULL, *tmp_inode;
1844 size_t old_ea_inode_quota = 0;
1845 unsigned int ea_ino;
1846
1847
1848#define header(x) ((struct ext4_xattr_header *)(x))
1849
1850 if (s->base) {
1851 BUFFER_TRACE(bs->bh, "get_write_access");
1852 error = ext4_journal_get_write_access(handle, bs->bh);
1853 if (error)
1854 goto cleanup;
1855 lock_buffer(bs->bh);
1856
1857 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1858 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1859
1860 /*
1861 * This must happen under buffer lock for
1862 * ext4_xattr_block_set() to reliably detect modified
1863 * block
1864 */
1865 if (ea_block_cache)
1866 mb_cache_entry_delete(ea_block_cache, hash,
1867 bs->bh->b_blocknr);
1868 ea_bdebug(bs->bh, "modifying in-place");
1869 error = ext4_xattr_set_entry(i, s, handle, inode,
1870 true /* is_block */);
1871 ext4_xattr_block_csum_set(inode, bs->bh);
1872 unlock_buffer(bs->bh);
1873 if (error == -EFSCORRUPTED)
1874 goto bad_block;
1875 if (!error)
1876 error = ext4_handle_dirty_metadata(handle,
1877 inode,
1878 bs->bh);
1879 if (error)
1880 goto cleanup;
1881 goto inserted;
1882 } else {
1883 int offset = (char *)s->here - bs->bh->b_data;
1884
1885 unlock_buffer(bs->bh);
1886 ea_bdebug(bs->bh, "cloning");
1887 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1888 error = -ENOMEM;
1889 if (s->base == NULL)
1890 goto cleanup;
1891 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1892 s->first = ENTRY(header(s->base)+1);
1893 header(s->base)->h_refcount = cpu_to_le32(1);
1894 s->here = ENTRY(s->base + offset);
1895 s->end = s->base + bs->bh->b_size;
1896
1897 /*
1898 * If existing entry points to an xattr inode, we need
1899 * to prevent ext4_xattr_set_entry() from decrementing
1900 * ref count on it because the reference belongs to the
1901 * original block. In this case, make the entry look
1902 * like it has an empty value.
1903 */
1904 if (!s->not_found && s->here->e_value_inum) {
1905 ea_ino = le32_to_cpu(s->here->e_value_inum);
1906 error = ext4_xattr_inode_iget(inode, ea_ino,
1907 le32_to_cpu(s->here->e_hash),
1908 &tmp_inode);
1909 if (error)
1910 goto cleanup;
1911
1912 if (!ext4_test_inode_state(tmp_inode,
1913 EXT4_STATE_LUSTRE_EA_INODE)) {
1914 /*
1915 * Defer quota free call for previous
1916 * inode until success is guaranteed.
1917 */
1918 old_ea_inode_quota = le32_to_cpu(
1919 s->here->e_value_size);
1920 }
1921 iput(tmp_inode);
1922
1923 s->here->e_value_inum = 0;
1924 s->here->e_value_size = 0;
1925 }
1926 }
1927 } else {
1928 /* Allocate a buffer where we construct the new block. */
1929 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1930 /* assert(header == s->base) */
1931 error = -ENOMEM;
1932 if (s->base == NULL)
1933 goto cleanup;
1934 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1935 header(s->base)->h_blocks = cpu_to_le32(1);
1936 header(s->base)->h_refcount = cpu_to_le32(1);
1937 s->first = ENTRY(header(s->base)+1);
1938 s->here = ENTRY(header(s->base)+1);
1939 s->end = s->base + sb->s_blocksize;
1940 }
1941
1942 error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1943 if (error == -EFSCORRUPTED)
1944 goto bad_block;
1945 if (error)
1946 goto cleanup;
1947
1948 if (i->value && s->here->e_value_inum) {
1949 /*
1950 * A ref count on ea_inode has been taken as part of the call to
1951 * ext4_xattr_set_entry() above. We would like to drop this
1952 * extra ref but we have to wait until the xattr block is
1953 * initialized and has its own ref count on the ea_inode.
1954 */
1955 ea_ino = le32_to_cpu(s->here->e_value_inum);
1956 error = ext4_xattr_inode_iget(inode, ea_ino,
1957 le32_to_cpu(s->here->e_hash),
1958 &ea_inode);
1959 if (error) {
1960 ea_inode = NULL;
1961 goto cleanup;
1962 }
1963 }
1964
1965inserted:
1966 if (!IS_LAST_ENTRY(s->first)) {
1967 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1968 &ce);
1969 if (new_bh) {
1970 /* We found an identical block in the cache. */
1971 if (new_bh == bs->bh)
1972 ea_bdebug(new_bh, "keeping");
1973 else {
1974 u32 ref;
1975
1976 WARN_ON_ONCE(dquot_initialize_needed(inode));
1977
1978 /* The old block is released after updating
1979 the inode. */
1980 error = dquot_alloc_block(inode,
1981 EXT4_C2B(EXT4_SB(sb), 1));
1982 if (error)
1983 goto cleanup;
1984 BUFFER_TRACE(new_bh, "get_write_access");
1985 error = ext4_journal_get_write_access(handle,
1986 new_bh);
1987 if (error)
1988 goto cleanup_dquot;
1989 lock_buffer(new_bh);
1990 /*
1991 * We have to be careful about races with
1992 * freeing, rehashing or adding references to
1993 * xattr block. Once we hold buffer lock xattr
1994 * block's state is stable so we can check
1995 * whether the block got freed / rehashed or
1996 * not. Since we unhash mbcache entry under
1997 * buffer lock when freeing / rehashing xattr
1998 * block, checking whether entry is still
1999 * hashed is reliable. Same rules hold for
2000 * e_reusable handling.
2001 */
2002 if (hlist_bl_unhashed(&ce->e_hash_list) ||
2003 !ce->e_reusable) {
2004 /*
2005 * Undo everything and check mbcache
2006 * again.
2007 */
2008 unlock_buffer(new_bh);
2009 dquot_free_block(inode,
2010 EXT4_C2B(EXT4_SB(sb),
2011 1));
2012 brelse(new_bh);
2013 mb_cache_entry_put(ea_block_cache, ce);
2014 ce = NULL;
2015 new_bh = NULL;
2016 goto inserted;
2017 }
2018 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2019 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2020 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2021 ce->e_reusable = 0;
2022 ea_bdebug(new_bh, "reusing; refcount now=%d",
2023 ref);
2024 ext4_xattr_block_csum_set(inode, new_bh);
2025 unlock_buffer(new_bh);
2026 error = ext4_handle_dirty_metadata(handle,
2027 inode,
2028 new_bh);
2029 if (error)
2030 goto cleanup_dquot;
2031 }
2032 mb_cache_entry_touch(ea_block_cache, ce);
2033 mb_cache_entry_put(ea_block_cache, ce);
2034 ce = NULL;
2035 } else if (bs->bh && s->base == bs->bh->b_data) {
2036 /* We were modifying this block in-place. */
2037 ea_bdebug(bs->bh, "keeping this block");
2038 ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2039 new_bh = bs->bh;
2040 get_bh(new_bh);
2041 } else {
2042 /* We need to allocate a new block */
2043 ext4_fsblk_t goal, block;
2044
2045 WARN_ON_ONCE(dquot_initialize_needed(inode));
2046
2047 goal = ext4_group_first_block_no(sb,
2048 EXT4_I(inode)->i_block_group);
2049
2050 /* non-extent files can't have physical blocks past 2^32 */
2051 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2052 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2053
2054 block = ext4_new_meta_blocks(handle, inode, goal, 0,
2055 NULL, &error);
2056 if (error)
2057 goto cleanup;
2058
2059 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2060 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2061
2062 ea_idebug(inode, "creating block %llu",
2063 (unsigned long long)block);
2064
2065 new_bh = sb_getblk(sb, block);
2066 if (unlikely(!new_bh)) {
2067 error = -ENOMEM;
2068getblk_failed:
2069 ext4_free_blocks(handle, inode, NULL, block, 1,
2070 EXT4_FREE_BLOCKS_METADATA);
2071 goto cleanup;
2072 }
2073 error = ext4_xattr_inode_inc_ref_all(handle, inode,
2074 ENTRY(header(s->base)+1));
2075 if (error)
2076 goto getblk_failed;
2077 if (ea_inode) {
2078 /* Drop the extra ref on ea_inode. */
2079 error = ext4_xattr_inode_dec_ref(handle,
2080 ea_inode);
2081 if (error)
2082 ext4_warning_inode(ea_inode,
2083 "dec ref error=%d",
2084 error);
2085 iput(ea_inode);
2086 ea_inode = NULL;
2087 }
2088
2089 lock_buffer(new_bh);
2090 error = ext4_journal_get_create_access(handle, new_bh);
2091 if (error) {
2092 unlock_buffer(new_bh);
2093 error = -EIO;
2094 goto getblk_failed;
2095 }
2096 memcpy(new_bh->b_data, s->base, new_bh->b_size);
2097 ext4_xattr_block_csum_set(inode, new_bh);
2098 set_buffer_uptodate(new_bh);
2099 unlock_buffer(new_bh);
2100 ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2101 error = ext4_handle_dirty_metadata(handle, inode,
2102 new_bh);
2103 if (error)
2104 goto cleanup;
2105 }
2106 }
2107
2108 if (old_ea_inode_quota)
2109 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2110
2111 /* Update the inode. */
2112 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2113
2114 /* Drop the previous xattr block. */
2115 if (bs->bh && bs->bh != new_bh) {
2116 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2117
2118 ext4_xattr_release_block(handle, inode, bs->bh,
2119 &ea_inode_array,
2120 0 /* extra_credits */);
2121 ext4_xattr_inode_array_free(ea_inode_array);
2122 }
2123 error = 0;
2124
2125cleanup:
2126 if (ea_inode) {
2127 int error2;
2128
2129 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2130 if (error2)
2131 ext4_warning_inode(ea_inode, "dec ref error=%d",
2132 error2);
2133
2134 /* If there was an error, revert the quota charge. */
2135 if (error)
2136 ext4_xattr_inode_free_quota(inode, ea_inode,
2137 i_size_read(ea_inode));
2138 iput(ea_inode);
2139 }
2140 if (ce)
2141 mb_cache_entry_put(ea_block_cache, ce);
2142 brelse(new_bh);
2143 if (!(bs->bh && s->base == bs->bh->b_data))
2144 kfree(s->base);
2145
2146 return error;
2147
2148cleanup_dquot:
2149 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2150 goto cleanup;
2151
2152bad_block:
2153 EXT4_ERROR_INODE(inode, "bad block %llu",
2154 EXT4_I(inode)->i_file_acl);
2155 goto cleanup;
2156
2157#undef header
2158}
2159
2160int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2161 struct ext4_xattr_ibody_find *is)
2162{
2163 struct ext4_xattr_ibody_header *header;
2164 struct ext4_inode *raw_inode;
2165 int error;
2166
2167 if (EXT4_I(inode)->i_extra_isize == 0)
2168 return 0;
2169 raw_inode = ext4_raw_inode(&is->iloc);
2170 header = IHDR(inode, raw_inode);
2171 is->s.base = is->s.first = IFIRST(header);
2172 is->s.here = is->s.first;
2173 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2174 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2175 error = xattr_check_inode(inode, header, is->s.end);
2176 if (error)
2177 return error;
2178 /* Find the named attribute. */
2179 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2180 i->name_index, i->name, 0);
2181 if (error && error != -ENODATA)
2182 return error;
2183 is->s.not_found = error;
2184 }
2185 return 0;
2186}
2187
2188int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
2189 struct ext4_xattr_info *i,
2190 struct ext4_xattr_ibody_find *is)
2191{
2192 struct ext4_xattr_ibody_header *header;
2193 struct ext4_xattr_search *s = &is->s;
2194 int error;
2195
2196 if (EXT4_I(inode)->i_extra_isize == 0)
2197 return -ENOSPC;
2198 error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2199 if (error)
2200 return error;
2201 header = IHDR(inode, ext4_raw_inode(&is->iloc));
2202 if (!IS_LAST_ENTRY(s->first)) {
2203 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2204 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2205 } else {
2206 header->h_magic = cpu_to_le32(0);
2207 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2208 }
2209 return 0;
2210}
2211
2212static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2213 struct ext4_xattr_info *i,
2214 struct ext4_xattr_ibody_find *is)
2215{
2216 struct ext4_xattr_ibody_header *header;
2217 struct ext4_xattr_search *s = &is->s;
2218 int error;
2219
2220 if (EXT4_I(inode)->i_extra_isize == 0)
2221 return -ENOSPC;
2222 error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2223 if (error)
2224 return error;
2225 header = IHDR(inode, ext4_raw_inode(&is->iloc));
2226 if (!IS_LAST_ENTRY(s->first)) {
2227 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2228 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2229 } else {
2230 header->h_magic = cpu_to_le32(0);
2231 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2232 }
2233 return 0;
2234}
2235
2236static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2237 struct ext4_xattr_info *i)
2238{
2239 void *value;
2240
2241 /* When e_value_inum is set the value is stored externally. */
2242 if (s->here->e_value_inum)
2243 return 0;
2244 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2245 return 0;
2246 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2247 return !memcmp(value, i->value, i->value_len);
2248}
2249
2250static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2251{
2252 struct buffer_head *bh;
2253 int error;
2254
2255 if (!EXT4_I(inode)->i_file_acl)
2256 return NULL;
2257 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2258 if (IS_ERR(bh))
2259 return bh;
2260 error = ext4_xattr_check_block(inode, bh);
2261 if (error) {
2262 brelse(bh);
2263 return ERR_PTR(error);
2264 }
2265 return bh;
2266}
2267
2268/*
2269 * ext4_xattr_set_handle()
2270 *
2271 * Create, replace or remove an extended attribute for this inode. Value
2272 * is NULL to remove an existing extended attribute, and non-NULL to
2273 * either replace an existing extended attribute, or create a new extended
2274 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2275 * specify that an extended attribute must exist and must not exist
2276 * previous to the call, respectively.
2277 *
2278 * Returns 0, or a negative error number on failure.
2279 */
2280int
2281ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2282 const char *name, const void *value, size_t value_len,
2283 int flags)
2284{
2285 struct ext4_xattr_info i = {
2286 .name_index = name_index,
2287 .name = name,
2288 .value = value,
2289 .value_len = value_len,
2290 .in_inode = 0,
2291 };
2292 struct ext4_xattr_ibody_find is = {
2293 .s = { .not_found = -ENODATA, },
2294 };
2295 struct ext4_xattr_block_find bs = {
2296 .s = { .not_found = -ENODATA, },
2297 };
2298 int no_expand;
2299 int error;
2300
2301 if (!name)
2302 return -EINVAL;
2303 if (strlen(name) > 255)
2304 return -ERANGE;
2305
2306 ext4_write_lock_xattr(inode, &no_expand);
2307
2308 /* Check journal credits under write lock. */
2309 if (ext4_handle_valid(handle)) {
2310 struct buffer_head *bh;
2311 int credits;
2312
2313 bh = ext4_xattr_get_block(inode);
2314 if (IS_ERR(bh)) {
2315 error = PTR_ERR(bh);
2316 goto cleanup;
2317 }
2318
2319 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2320 value_len,
2321 flags & XATTR_CREATE);
2322 brelse(bh);
2323
2324 if (jbd2_handle_buffer_credits(handle) < credits) {
2325 error = -ENOSPC;
2326 goto cleanup;
2327 }
2328 }
2329
2330 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2331 if (error)
2332 goto cleanup;
2333
2334 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2335 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2336 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2337 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2338 }
2339
2340 error = ext4_xattr_ibody_find(inode, &i, &is);
2341 if (error)
2342 goto cleanup;
2343 if (is.s.not_found)
2344 error = ext4_xattr_block_find(inode, &i, &bs);
2345 if (error)
2346 goto cleanup;
2347 if (is.s.not_found && bs.s.not_found) {
2348 error = -ENODATA;
2349 if (flags & XATTR_REPLACE)
2350 goto cleanup;
2351 error = 0;
2352 if (!value)
2353 goto cleanup;
2354 } else {
2355 error = -EEXIST;
2356 if (flags & XATTR_CREATE)
2357 goto cleanup;
2358 }
2359
2360 if (!value) {
2361 if (!is.s.not_found)
2362 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2363 else if (!bs.s.not_found)
2364 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2365 } else {
2366 error = 0;
2367 /* Xattr value did not change? Save us some work and bail out */
2368 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2369 goto cleanup;
2370 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2371 goto cleanup;
2372
2373 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2374 (EXT4_XATTR_SIZE(i.value_len) >
2375 EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2376 i.in_inode = 1;
2377retry_inode:
2378 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2379 if (!error && !bs.s.not_found) {
2380 i.value = NULL;
2381 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2382 } else if (error == -ENOSPC) {
2383 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2384 brelse(bs.bh);
2385 bs.bh = NULL;
2386 error = ext4_xattr_block_find(inode, &i, &bs);
2387 if (error)
2388 goto cleanup;
2389 }
2390 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2391 if (!error && !is.s.not_found) {
2392 i.value = NULL;
2393 error = ext4_xattr_ibody_set(handle, inode, &i,
2394 &is);
2395 } else if (error == -ENOSPC) {
2396 /*
2397 * Xattr does not fit in the block, store at
2398 * external inode if possible.
2399 */
2400 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2401 !i.in_inode) {
2402 i.in_inode = 1;
2403 goto retry_inode;
2404 }
2405 }
2406 }
2407 }
2408 if (!error) {
2409 ext4_xattr_update_super_block(handle, inode->i_sb);
2410 inode->i_ctime = current_time(inode);
2411 if (!value)
2412 no_expand = 0;
2413 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2414 /*
2415 * The bh is consumed by ext4_mark_iloc_dirty, even with
2416 * error != 0.
2417 */
2418 is.iloc.bh = NULL;
2419 if (IS_SYNC(inode))
2420 ext4_handle_sync(handle);
2421 }
2422
2423cleanup:
2424 brelse(is.iloc.bh);
2425 brelse(bs.bh);
2426 ext4_write_unlock_xattr(inode, &no_expand);
2427 return error;
2428}
2429
2430int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2431 bool is_create, int *credits)
2432{
2433 struct buffer_head *bh;
2434 int err;
2435
2436 *credits = 0;
2437
2438 if (!EXT4_SB(inode->i_sb)->s_journal)
2439 return 0;
2440
2441 down_read(&EXT4_I(inode)->xattr_sem);
2442
2443 bh = ext4_xattr_get_block(inode);
2444 if (IS_ERR(bh)) {
2445 err = PTR_ERR(bh);
2446 } else {
2447 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2448 value_len, is_create);
2449 brelse(bh);
2450 err = 0;
2451 }
2452
2453 up_read(&EXT4_I(inode)->xattr_sem);
2454 return err;
2455}
2456
2457/*
2458 * ext4_xattr_set()
2459 *
2460 * Like ext4_xattr_set_handle, but start from an inode. This extended
2461 * attribute modification is a filesystem transaction by itself.
2462 *
2463 * Returns 0, or a negative error number on failure.
2464 */
2465int
2466ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2467 const void *value, size_t value_len, int flags)
2468{
2469 handle_t *handle;
2470 struct super_block *sb = inode->i_sb;
2471 int error, retries = 0;
2472 int credits;
2473
2474 error = dquot_initialize(inode);
2475 if (error)
2476 return error;
2477
2478retry:
2479 error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2480 &credits);
2481 if (error)
2482 return error;
2483
2484 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2485 if (IS_ERR(handle)) {
2486 error = PTR_ERR(handle);
2487 } else {
2488 int error2;
2489
2490 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2491 value, value_len, flags);
2492 error2 = ext4_journal_stop(handle);
2493 if (error == -ENOSPC &&
2494 ext4_should_retry_alloc(sb, &retries))
2495 goto retry;
2496 if (error == 0)
2497 error = error2;
2498 }
2499
2500 return error;
2501}
2502
2503/*
2504 * Shift the EA entries in the inode to create space for the increased
2505 * i_extra_isize.
2506 */
2507static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2508 int value_offs_shift, void *to,
2509 void *from, size_t n)
2510{
2511 struct ext4_xattr_entry *last = entry;
2512 int new_offs;
2513
2514 /* We always shift xattr headers further thus offsets get lower */
2515 BUG_ON(value_offs_shift > 0);
2516
2517 /* Adjust the value offsets of the entries */
2518 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2519 if (!last->e_value_inum && last->e_value_size) {
2520 new_offs = le16_to_cpu(last->e_value_offs) +
2521 value_offs_shift;
2522 last->e_value_offs = cpu_to_le16(new_offs);
2523 }
2524 }
2525 /* Shift the entries by n bytes */
2526 memmove(to, from, n);
2527}
2528
2529/*
2530 * Move xattr pointed to by 'entry' from inode into external xattr block
2531 */
2532static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2533 struct ext4_inode *raw_inode,
2534 struct ext4_xattr_entry *entry)
2535{
2536 struct ext4_xattr_ibody_find *is = NULL;
2537 struct ext4_xattr_block_find *bs = NULL;
2538 char *buffer = NULL, *b_entry_name = NULL;
2539 size_t value_size = le32_to_cpu(entry->e_value_size);
2540 struct ext4_xattr_info i = {
2541 .value = NULL,
2542 .value_len = 0,
2543 .name_index = entry->e_name_index,
2544 .in_inode = !!entry->e_value_inum,
2545 };
2546 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2547 int error;
2548
2549 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2550 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2551 buffer = kmalloc(value_size, GFP_NOFS);
2552 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2553 if (!is || !bs || !buffer || !b_entry_name) {
2554 error = -ENOMEM;
2555 goto out;
2556 }
2557
2558 is->s.not_found = -ENODATA;
2559 bs->s.not_found = -ENODATA;
2560 is->iloc.bh = NULL;
2561 bs->bh = NULL;
2562
2563 /* Save the entry name and the entry value */
2564 if (entry->e_value_inum) {
2565 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2566 if (error)
2567 goto out;
2568 } else {
2569 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2570 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2571 }
2572
2573 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2574 b_entry_name[entry->e_name_len] = '\0';
2575 i.name = b_entry_name;
2576
2577 error = ext4_get_inode_loc(inode, &is->iloc);
2578 if (error)
2579 goto out;
2580
2581 error = ext4_xattr_ibody_find(inode, &i, is);
2582 if (error)
2583 goto out;
2584
2585 /* Remove the chosen entry from the inode */
2586 error = ext4_xattr_ibody_set(handle, inode, &i, is);
2587 if (error)
2588 goto out;
2589
2590 i.value = buffer;
2591 i.value_len = value_size;
2592 error = ext4_xattr_block_find(inode, &i, bs);
2593 if (error)
2594 goto out;
2595
2596 /* Add entry which was removed from the inode into the block */
2597 error = ext4_xattr_block_set(handle, inode, &i, bs);
2598 if (error)
2599 goto out;
2600 error = 0;
2601out:
2602 kfree(b_entry_name);
2603 kfree(buffer);
2604 if (is)
2605 brelse(is->iloc.bh);
2606 if (bs)
2607 brelse(bs->bh);
2608 kfree(is);
2609 kfree(bs);
2610
2611 return error;
2612}
2613
2614static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2615 struct ext4_inode *raw_inode,
2616 int isize_diff, size_t ifree,
2617 size_t bfree, int *total_ino)
2618{
2619 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2620 struct ext4_xattr_entry *small_entry;
2621 struct ext4_xattr_entry *entry;
2622 struct ext4_xattr_entry *last;
2623 unsigned int entry_size; /* EA entry size */
2624 unsigned int total_size; /* EA entry size + value size */
2625 unsigned int min_total_size;
2626 int error;
2627
2628 while (isize_diff > ifree) {
2629 entry = NULL;
2630 small_entry = NULL;
2631 min_total_size = ~0U;
2632 last = IFIRST(header);
2633 /* Find the entry best suited to be pushed into EA block */
2634 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2635 /* never move system.data out of the inode */
2636 if ((last->e_name_len == 4) &&
2637 (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2638 !memcmp(last->e_name, "data", 4))
2639 continue;
2640 total_size = EXT4_XATTR_LEN(last->e_name_len);
2641 if (!last->e_value_inum)
2642 total_size += EXT4_XATTR_SIZE(
2643 le32_to_cpu(last->e_value_size));
2644 if (total_size <= bfree &&
2645 total_size < min_total_size) {
2646 if (total_size + ifree < isize_diff) {
2647 small_entry = last;
2648 } else {
2649 entry = last;
2650 min_total_size = total_size;
2651 }
2652 }
2653 }
2654
2655 if (entry == NULL) {
2656 if (small_entry == NULL)
2657 return -ENOSPC;
2658 entry = small_entry;
2659 }
2660
2661 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2662 total_size = entry_size;
2663 if (!entry->e_value_inum)
2664 total_size += EXT4_XATTR_SIZE(
2665 le32_to_cpu(entry->e_value_size));
2666 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2667 entry);
2668 if (error)
2669 return error;
2670
2671 *total_ino -= entry_size;
2672 ifree += total_size;
2673 bfree -= total_size;
2674 }
2675
2676 return 0;
2677}
2678
2679/*
2680 * Expand an inode by new_extra_isize bytes when EAs are present.
2681 * Returns 0 on success or negative error number on failure.
2682 */
2683int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2684 struct ext4_inode *raw_inode, handle_t *handle)
2685{
2686 struct ext4_xattr_ibody_header *header;
2687 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2688 static unsigned int mnt_count;
2689 size_t min_offs;
2690 size_t ifree, bfree;
2691 int total_ino;
2692 void *base, *end;
2693 int error = 0, tried_min_extra_isize = 0;
2694 int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2695 int isize_diff; /* How much do we need to grow i_extra_isize */
2696
2697retry:
2698 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2699 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2700 return 0;
2701
2702 header = IHDR(inode, raw_inode);
2703
2704 /*
2705 * Check if enough free space is available in the inode to shift the
2706 * entries ahead by new_extra_isize.
2707 */
2708
2709 base = IFIRST(header);
2710 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2711 min_offs = end - base;
2712 total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2713
2714 error = xattr_check_inode(inode, header, end);
2715 if (error)
2716 goto cleanup;
2717
2718 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2719 if (ifree >= isize_diff)
2720 goto shift;
2721
2722 /*
2723 * Enough free space isn't available in the inode, check if
2724 * EA block can hold new_extra_isize bytes.
2725 */
2726 if (EXT4_I(inode)->i_file_acl) {
2727 struct buffer_head *bh;
2728
2729 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2730 if (IS_ERR(bh)) {
2731 error = PTR_ERR(bh);
2732 goto cleanup;
2733 }
2734 error = ext4_xattr_check_block(inode, bh);
2735 if (error) {
2736 brelse(bh);
2737 goto cleanup;
2738 }
2739 base = BHDR(bh);
2740 end = bh->b_data + bh->b_size;
2741 min_offs = end - base;
2742 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2743 NULL);
2744 brelse(bh);
2745 if (bfree + ifree < isize_diff) {
2746 if (!tried_min_extra_isize && s_min_extra_isize) {
2747 tried_min_extra_isize++;
2748 new_extra_isize = s_min_extra_isize;
2749 goto retry;
2750 }
2751 error = -ENOSPC;
2752 goto cleanup;
2753 }
2754 } else {
2755 bfree = inode->i_sb->s_blocksize;
2756 }
2757
2758 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2759 isize_diff, ifree, bfree,
2760 &total_ino);
2761 if (error) {
2762 if (error == -ENOSPC && !tried_min_extra_isize &&
2763 s_min_extra_isize) {
2764 tried_min_extra_isize++;
2765 new_extra_isize = s_min_extra_isize;
2766 goto retry;
2767 }
2768 goto cleanup;
2769 }
2770shift:
2771 /* Adjust the offsets and shift the remaining entries ahead */
2772 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2773 - new_extra_isize, (void *)raw_inode +
2774 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2775 (void *)header, total_ino);
2776 EXT4_I(inode)->i_extra_isize = new_extra_isize;
2777
2778cleanup:
2779 if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2780 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2781 inode->i_ino);
2782 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2783 }
2784 return error;
2785}
2786
2787#define EIA_INCR 16 /* must be 2^n */
2788#define EIA_MASK (EIA_INCR - 1)
2789
2790/* Add the large xattr @inode into @ea_inode_array for deferred iput().
2791 * If @ea_inode_array is new or full it will be grown and the old
2792 * contents copied over.
2793 */
2794static int
2795ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2796 struct inode *inode)
2797{
2798 if (*ea_inode_array == NULL) {
2799 /*
2800 * Start with 15 inodes, so it fits into a power-of-two size.
2801 * If *ea_inode_array is NULL, this is essentially offsetof()
2802 */
2803 (*ea_inode_array) =
2804 kmalloc(offsetof(struct ext4_xattr_inode_array,
2805 inodes[EIA_MASK]),
2806 GFP_NOFS);
2807 if (*ea_inode_array == NULL)
2808 return -ENOMEM;
2809 (*ea_inode_array)->count = 0;
2810 } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2811 /* expand the array once all 15 + n * 16 slots are full */
2812 struct ext4_xattr_inode_array *new_array = NULL;
2813 int count = (*ea_inode_array)->count;
2814
2815 /* if new_array is NULL, this is essentially offsetof() */
2816 new_array = kmalloc(
2817 offsetof(struct ext4_xattr_inode_array,
2818 inodes[count + EIA_INCR]),
2819 GFP_NOFS);
2820 if (new_array == NULL)
2821 return -ENOMEM;
2822 memcpy(new_array, *ea_inode_array,
2823 offsetof(struct ext4_xattr_inode_array, inodes[count]));
2824 kfree(*ea_inode_array);
2825 *ea_inode_array = new_array;
2826 }
2827 (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2828 return 0;
2829}
2830
2831/*
2832 * ext4_xattr_delete_inode()
2833 *
2834 * Free extended attribute resources associated with this inode. Traverse
2835 * all entries and decrement reference on any xattr inodes associated with this
2836 * inode. This is called immediately before an inode is freed. We have exclusive
2837 * access to the inode. If an orphan inode is deleted it will also release its
2838 * references on xattr block and xattr inodes.
2839 */
2840int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2841 struct ext4_xattr_inode_array **ea_inode_array,
2842 int extra_credits)
2843{
2844 struct buffer_head *bh = NULL;
2845 struct ext4_xattr_ibody_header *header;
2846 struct ext4_iloc iloc = { .bh = NULL };
2847 struct ext4_xattr_entry *entry;
2848 struct inode *ea_inode;
2849 int error;
2850
2851 error = ext4_journal_ensure_credits(handle, extra_credits,
2852 ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2853 if (error < 0) {
2854 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2855 goto cleanup;
2856 }
2857
2858 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2859 ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2860
2861 error = ext4_get_inode_loc(inode, &iloc);
2862 if (error) {
2863 EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2864 goto cleanup;
2865 }
2866
2867 error = ext4_journal_get_write_access(handle, iloc.bh);
2868 if (error) {
2869 EXT4_ERROR_INODE(inode, "write access (error %d)",
2870 error);
2871 goto cleanup;
2872 }
2873
2874 header = IHDR(inode, ext4_raw_inode(&iloc));
2875 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2876 ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2877 IFIRST(header),
2878 false /* block_csum */,
2879 ea_inode_array,
2880 extra_credits,
2881 false /* skip_quota */);
2882 }
2883
2884 if (EXT4_I(inode)->i_file_acl) {
2885 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2886 if (IS_ERR(bh)) {
2887 error = PTR_ERR(bh);
2888 if (error == -EIO) {
2889 EXT4_ERROR_INODE_ERR(inode, EIO,
2890 "block %llu read error",
2891 EXT4_I(inode)->i_file_acl);
2892 }
2893 bh = NULL;
2894 goto cleanup;
2895 }
2896 error = ext4_xattr_check_block(inode, bh);
2897 if (error)
2898 goto cleanup;
2899
2900 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2901 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2902 entry = EXT4_XATTR_NEXT(entry)) {
2903 if (!entry->e_value_inum)
2904 continue;
2905 error = ext4_xattr_inode_iget(inode,
2906 le32_to_cpu(entry->e_value_inum),
2907 le32_to_cpu(entry->e_hash),
2908 &ea_inode);
2909 if (error)
2910 continue;
2911 ext4_xattr_inode_free_quota(inode, ea_inode,
2912 le32_to_cpu(entry->e_value_size));
2913 iput(ea_inode);
2914 }
2915
2916 }
2917
2918 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2919 extra_credits);
2920 /*
2921 * Update i_file_acl value in the same transaction that releases
2922 * block.
2923 */
2924 EXT4_I(inode)->i_file_acl = 0;
2925 error = ext4_mark_inode_dirty(handle, inode);
2926 if (error) {
2927 EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2928 error);
2929 goto cleanup;
2930 }
2931 }
2932 error = 0;
2933cleanup:
2934 brelse(iloc.bh);
2935 brelse(bh);
2936 return error;
2937}
2938
2939void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2940{
2941 int idx;
2942
2943 if (ea_inode_array == NULL)
2944 return;
2945
2946 for (idx = 0; idx < ea_inode_array->count; ++idx)
2947 iput(ea_inode_array->inodes[idx]);
2948 kfree(ea_inode_array);
2949}
2950
2951/*
2952 * ext4_xattr_block_cache_insert()
2953 *
2954 * Create a new entry in the extended attribute block cache, and insert
2955 * it unless such an entry is already in the cache.
2956 *
2957 * Returns 0, or a negative error number on failure.
2958 */
2959static void
2960ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2961 struct buffer_head *bh)
2962{
2963 struct ext4_xattr_header *header = BHDR(bh);
2964 __u32 hash = le32_to_cpu(header->h_hash);
2965 int reusable = le32_to_cpu(header->h_refcount) <
2966 EXT4_XATTR_REFCOUNT_MAX;
2967 int error;
2968
2969 if (!ea_block_cache)
2970 return;
2971 error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2972 bh->b_blocknr, reusable);
2973 if (error) {
2974 if (error == -EBUSY)
2975 ea_bdebug(bh, "already in cache");
2976 } else
2977 ea_bdebug(bh, "inserting [%x]", (int)hash);
2978}
2979
2980/*
2981 * ext4_xattr_cmp()
2982 *
2983 * Compare two extended attribute blocks for equality.
2984 *
2985 * Returns 0 if the blocks are equal, 1 if they differ, and
2986 * a negative error number on errors.
2987 */
2988static int
2989ext4_xattr_cmp(struct ext4_xattr_header *header1,
2990 struct ext4_xattr_header *header2)
2991{
2992 struct ext4_xattr_entry *entry1, *entry2;
2993
2994 entry1 = ENTRY(header1+1);
2995 entry2 = ENTRY(header2+1);
2996 while (!IS_LAST_ENTRY(entry1)) {
2997 if (IS_LAST_ENTRY(entry2))
2998 return 1;
2999 if (entry1->e_hash != entry2->e_hash ||
3000 entry1->e_name_index != entry2->e_name_index ||
3001 entry1->e_name_len != entry2->e_name_len ||
3002 entry1->e_value_size != entry2->e_value_size ||
3003 entry1->e_value_inum != entry2->e_value_inum ||
3004 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3005 return 1;
3006 if (!entry1->e_value_inum &&
3007 memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3008 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3009 le32_to_cpu(entry1->e_value_size)))
3010 return 1;
3011
3012 entry1 = EXT4_XATTR_NEXT(entry1);
3013 entry2 = EXT4_XATTR_NEXT(entry2);
3014 }
3015 if (!IS_LAST_ENTRY(entry2))
3016 return 1;
3017 return 0;
3018}
3019
3020/*
3021 * ext4_xattr_block_cache_find()
3022 *
3023 * Find an identical extended attribute block.
3024 *
3025 * Returns a pointer to the block found, or NULL if such a block was
3026 * not found or an error occurred.
3027 */
3028static struct buffer_head *
3029ext4_xattr_block_cache_find(struct inode *inode,
3030 struct ext4_xattr_header *header,
3031 struct mb_cache_entry **pce)
3032{
3033 __u32 hash = le32_to_cpu(header->h_hash);
3034 struct mb_cache_entry *ce;
3035 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3036
3037 if (!ea_block_cache)
3038 return NULL;
3039 if (!header->h_hash)
3040 return NULL; /* never share */
3041 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3042 ce = mb_cache_entry_find_first(ea_block_cache, hash);
3043 while (ce) {
3044 struct buffer_head *bh;
3045
3046 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3047 if (IS_ERR(bh)) {
3048 if (PTR_ERR(bh) == -ENOMEM)
3049 return NULL;
3050 bh = NULL;
3051 EXT4_ERROR_INODE(inode, "block %lu read error",
3052 (unsigned long)ce->e_value);
3053 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3054 *pce = ce;
3055 return bh;
3056 }
3057 brelse(bh);
3058 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3059 }
3060 return NULL;
3061}
3062
3063#define NAME_HASH_SHIFT 5
3064#define VALUE_HASH_SHIFT 16
3065
3066/*
3067 * ext4_xattr_hash_entry()
3068 *
3069 * Compute the hash of an extended attribute.
3070 */
3071static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3072 size_t value_count)
3073{
3074 __u32 hash = 0;
3075
3076 while (name_len--) {
3077 hash = (hash << NAME_HASH_SHIFT) ^
3078 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3079 *name++;
3080 }
3081 while (value_count--) {
3082 hash = (hash << VALUE_HASH_SHIFT) ^
3083 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3084 le32_to_cpu(*value++);
3085 }
3086 return cpu_to_le32(hash);
3087}
3088
3089#undef NAME_HASH_SHIFT
3090#undef VALUE_HASH_SHIFT
3091
3092#define BLOCK_HASH_SHIFT 16
3093
3094/*
3095 * ext4_xattr_rehash()
3096 *
3097 * Re-compute the extended attribute hash value after an entry has changed.
3098 */
3099static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3100{
3101 struct ext4_xattr_entry *here;
3102 __u32 hash = 0;
3103
3104 here = ENTRY(header+1);
3105 while (!IS_LAST_ENTRY(here)) {
3106 if (!here->e_hash) {
3107 /* Block is not shared if an entry's hash value == 0 */
3108 hash = 0;
3109 break;
3110 }
3111 hash = (hash << BLOCK_HASH_SHIFT) ^
3112 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3113 le32_to_cpu(here->e_hash);
3114 here = EXT4_XATTR_NEXT(here);
3115 }
3116 header->h_hash = cpu_to_le32(hash);
3117}
3118
3119#undef BLOCK_HASH_SHIFT
3120
3121#define HASH_BUCKET_BITS 10
3122
3123struct mb_cache *
3124ext4_xattr_create_cache(void)
3125{
3126 return mb_cache_create(HASH_BUCKET_BITS);
3127}
3128
3129void ext4_xattr_destroy_cache(struct mb_cache *cache)
3130{
3131 if (cache)
3132 mb_cache_destroy(cache);
3133}
3134