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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(f...)
86# define ea_bdebug(f...)
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 inline const struct xattr_handler *
126ext4_xattr_handler(int name_index)
127{
128 const struct xattr_handler *handler = NULL;
129
130 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
131 handler = ext4_xattr_handler_map[name_index];
132 return handler;
133}
134
135/*
136 * Inode operation listxattr()
137 *
138 * dentry->d_inode->i_mutex: don't care
139 */
140ssize_t
141ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
142{
143 return ext4_xattr_list(dentry, buffer, size);
144}
145
146static int
147ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
148{
149 while (!IS_LAST_ENTRY(entry)) {
150 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
151 if ((void *)next >= end)
152 return -EIO;
153 entry = next;
154 }
155 return 0;
156}
157
158static inline int
159ext4_xattr_check_block(struct buffer_head *bh)
160{
161 int error;
162
163 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
164 BHDR(bh)->h_blocks != cpu_to_le32(1))
165 return -EIO;
166 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
167 return error;
168}
169
170static inline int
171ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
172{
173 size_t value_size = le32_to_cpu(entry->e_value_size);
174
175 if (entry->e_value_block != 0 || value_size > size ||
176 le16_to_cpu(entry->e_value_offs) + value_size > size)
177 return -EIO;
178 return 0;
179}
180
181static int
182ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
183 const char *name, size_t size, int sorted)
184{
185 struct ext4_xattr_entry *entry;
186 size_t name_len;
187 int cmp = 1;
188
189 if (name == NULL)
190 return -EINVAL;
191 name_len = strlen(name);
192 entry = *pentry;
193 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
194 cmp = name_index - entry->e_name_index;
195 if (!cmp)
196 cmp = name_len - entry->e_name_len;
197 if (!cmp)
198 cmp = memcmp(name, entry->e_name, name_len);
199 if (cmp <= 0 && (sorted || cmp == 0))
200 break;
201 }
202 *pentry = entry;
203 if (!cmp && ext4_xattr_check_entry(entry, size))
204 return -EIO;
205 return cmp ? -ENODATA : 0;
206}
207
208static int
209ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
210 void *buffer, size_t buffer_size)
211{
212 struct buffer_head *bh = NULL;
213 struct ext4_xattr_entry *entry;
214 size_t size;
215 int error;
216
217 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
218 name_index, name, buffer, (long)buffer_size);
219
220 error = -ENODATA;
221 if (!EXT4_I(inode)->i_file_acl)
222 goto cleanup;
223 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
224 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
225 if (!bh)
226 goto cleanup;
227 ea_bdebug(bh, "b_count=%d, refcount=%d",
228 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
229 if (ext4_xattr_check_block(bh)) {
230bad_block:
231 EXT4_ERROR_INODE(inode, "bad block %llu",
232 EXT4_I(inode)->i_file_acl);
233 error = -EIO;
234 goto cleanup;
235 }
236 ext4_xattr_cache_insert(bh);
237 entry = BFIRST(bh);
238 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
239 if (error == -EIO)
240 goto bad_block;
241 if (error)
242 goto cleanup;
243 size = le32_to_cpu(entry->e_value_size);
244 if (buffer) {
245 error = -ERANGE;
246 if (size > buffer_size)
247 goto cleanup;
248 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
249 size);
250 }
251 error = size;
252
253cleanup:
254 brelse(bh);
255 return error;
256}
257
258static int
259ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
260 void *buffer, size_t buffer_size)
261{
262 struct ext4_xattr_ibody_header *header;
263 struct ext4_xattr_entry *entry;
264 struct ext4_inode *raw_inode;
265 struct ext4_iloc iloc;
266 size_t size;
267 void *end;
268 int error;
269
270 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
271 return -ENODATA;
272 error = ext4_get_inode_loc(inode, &iloc);
273 if (error)
274 return error;
275 raw_inode = ext4_raw_inode(&iloc);
276 header = IHDR(inode, raw_inode);
277 entry = IFIRST(header);
278 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
279 error = ext4_xattr_check_names(entry, end);
280 if (error)
281 goto cleanup;
282 error = ext4_xattr_find_entry(&entry, name_index, name,
283 end - (void *)entry, 0);
284 if (error)
285 goto cleanup;
286 size = le32_to_cpu(entry->e_value_size);
287 if (buffer) {
288 error = -ERANGE;
289 if (size > buffer_size)
290 goto cleanup;
291 memcpy(buffer, (void *)IFIRST(header) +
292 le16_to_cpu(entry->e_value_offs), size);
293 }
294 error = size;
295
296cleanup:
297 brelse(iloc.bh);
298 return error;
299}
300
301/*
302 * ext4_xattr_get()
303 *
304 * Copy an extended attribute into the buffer
305 * provided, or compute the buffer size required.
306 * Buffer is NULL to compute the size of the buffer required.
307 *
308 * Returns a negative error number on failure, or the number of bytes
309 * used / required on success.
310 */
311int
312ext4_xattr_get(struct inode *inode, int name_index, const char *name,
313 void *buffer, size_t buffer_size)
314{
315 int error;
316
317 down_read(&EXT4_I(inode)->xattr_sem);
318 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
319 buffer_size);
320 if (error == -ENODATA)
321 error = ext4_xattr_block_get(inode, name_index, name, buffer,
322 buffer_size);
323 up_read(&EXT4_I(inode)->xattr_sem);
324 return error;
325}
326
327static int
328ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
329 char *buffer, size_t buffer_size)
330{
331 size_t rest = buffer_size;
332
333 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
334 const struct xattr_handler *handler =
335 ext4_xattr_handler(entry->e_name_index);
336
337 if (handler) {
338 size_t size = handler->list(dentry, buffer, rest,
339 entry->e_name,
340 entry->e_name_len,
341 handler->flags);
342 if (buffer) {
343 if (size > rest)
344 return -ERANGE;
345 buffer += size;
346 }
347 rest -= size;
348 }
349 }
350 return buffer_size - rest;
351}
352
353static int
354ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
355{
356 struct inode *inode = dentry->d_inode;
357 struct buffer_head *bh = NULL;
358 int error;
359
360 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
361 buffer, (long)buffer_size);
362
363 error = 0;
364 if (!EXT4_I(inode)->i_file_acl)
365 goto cleanup;
366 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
367 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
368 error = -EIO;
369 if (!bh)
370 goto cleanup;
371 ea_bdebug(bh, "b_count=%d, refcount=%d",
372 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
373 if (ext4_xattr_check_block(bh)) {
374 EXT4_ERROR_INODE(inode, "bad block %llu",
375 EXT4_I(inode)->i_file_acl);
376 error = -EIO;
377 goto cleanup;
378 }
379 ext4_xattr_cache_insert(bh);
380 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
381
382cleanup:
383 brelse(bh);
384
385 return error;
386}
387
388static int
389ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
390{
391 struct inode *inode = dentry->d_inode;
392 struct ext4_xattr_ibody_header *header;
393 struct ext4_inode *raw_inode;
394 struct ext4_iloc iloc;
395 void *end;
396 int error;
397
398 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
399 return 0;
400 error = ext4_get_inode_loc(inode, &iloc);
401 if (error)
402 return error;
403 raw_inode = ext4_raw_inode(&iloc);
404 header = IHDR(inode, raw_inode);
405 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
406 error = ext4_xattr_check_names(IFIRST(header), end);
407 if (error)
408 goto cleanup;
409 error = ext4_xattr_list_entries(dentry, IFIRST(header),
410 buffer, buffer_size);
411
412cleanup:
413 brelse(iloc.bh);
414 return error;
415}
416
417/*
418 * ext4_xattr_list()
419 *
420 * Copy a list of attribute names into the buffer
421 * provided, or compute the buffer size required.
422 * Buffer is NULL to compute the size of the buffer required.
423 *
424 * Returns a negative error number on failure, or the number of bytes
425 * used / required on success.
426 */
427static int
428ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
429{
430 int ret, ret2;
431
432 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
433 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
434 if (ret < 0)
435 goto errout;
436 if (buffer) {
437 buffer += ret;
438 buffer_size -= ret;
439 }
440 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
441 if (ret < 0)
442 goto errout;
443 ret += ret2;
444errout:
445 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
446 return ret;
447}
448
449/*
450 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
451 * not set, set it.
452 */
453static void ext4_xattr_update_super_block(handle_t *handle,
454 struct super_block *sb)
455{
456 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
457 return;
458
459 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
460 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
461 ext4_handle_dirty_super(handle, sb);
462 }
463}
464
465/*
466 * Release the xattr block BH: If the reference count is > 1, decrement
467 * it; otherwise free the block.
468 */
469static void
470ext4_xattr_release_block(handle_t *handle, struct inode *inode,
471 struct buffer_head *bh)
472{
473 struct mb_cache_entry *ce = NULL;
474 int error = 0;
475
476 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
477 error = ext4_journal_get_write_access(handle, bh);
478 if (error)
479 goto out;
480
481 lock_buffer(bh);
482 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
483 ea_bdebug(bh, "refcount now=0; freeing");
484 if (ce)
485 mb_cache_entry_free(ce);
486 get_bh(bh);
487 ext4_free_blocks(handle, inode, bh, 0, 1,
488 EXT4_FREE_BLOCKS_METADATA |
489 EXT4_FREE_BLOCKS_FORGET);
490 } else {
491 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
492 error = ext4_handle_dirty_metadata(handle, inode, bh);
493 if (IS_SYNC(inode))
494 ext4_handle_sync(handle);
495 dquot_free_block(inode, 1);
496 ea_bdebug(bh, "refcount now=%d; releasing",
497 le32_to_cpu(BHDR(bh)->h_refcount));
498 if (ce)
499 mb_cache_entry_release(ce);
500 }
501 unlock_buffer(bh);
502out:
503 ext4_std_error(inode->i_sb, error);
504 return;
505}
506
507/*
508 * Find the available free space for EAs. This also returns the total number of
509 * bytes used by EA entries.
510 */
511static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
512 size_t *min_offs, void *base, int *total)
513{
514 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
515 *total += EXT4_XATTR_LEN(last->e_name_len);
516 if (!last->e_value_block && last->e_value_size) {
517 size_t offs = le16_to_cpu(last->e_value_offs);
518 if (offs < *min_offs)
519 *min_offs = offs;
520 }
521 }
522 return (*min_offs - ((void *)last - base) - sizeof(__u32));
523}
524
525struct ext4_xattr_info {
526 int name_index;
527 const char *name;
528 const void *value;
529 size_t value_len;
530};
531
532struct ext4_xattr_search {
533 struct ext4_xattr_entry *first;
534 void *base;
535 void *end;
536 struct ext4_xattr_entry *here;
537 int not_found;
538};
539
540static int
541ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
542{
543 struct ext4_xattr_entry *last;
544 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
545
546 /* Compute min_offs and last. */
547 last = s->first;
548 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
549 if (!last->e_value_block && last->e_value_size) {
550 size_t offs = le16_to_cpu(last->e_value_offs);
551 if (offs < min_offs)
552 min_offs = offs;
553 }
554 }
555 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
556 if (!s->not_found) {
557 if (!s->here->e_value_block && s->here->e_value_size) {
558 size_t size = le32_to_cpu(s->here->e_value_size);
559 free += EXT4_XATTR_SIZE(size);
560 }
561 free += EXT4_XATTR_LEN(name_len);
562 }
563 if (i->value) {
564 if (free < EXT4_XATTR_SIZE(i->value_len) ||
565 free < EXT4_XATTR_LEN(name_len) +
566 EXT4_XATTR_SIZE(i->value_len))
567 return -ENOSPC;
568 }
569
570 if (i->value && s->not_found) {
571 /* Insert the new name. */
572 size_t size = EXT4_XATTR_LEN(name_len);
573 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
574 memmove((void *)s->here + size, s->here, rest);
575 memset(s->here, 0, size);
576 s->here->e_name_index = i->name_index;
577 s->here->e_name_len = name_len;
578 memcpy(s->here->e_name, i->name, name_len);
579 } else {
580 if (!s->here->e_value_block && s->here->e_value_size) {
581 void *first_val = s->base + min_offs;
582 size_t offs = le16_to_cpu(s->here->e_value_offs);
583 void *val = s->base + offs;
584 size_t size = EXT4_XATTR_SIZE(
585 le32_to_cpu(s->here->e_value_size));
586
587 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
588 /* The old and the new value have the same
589 size. Just replace. */
590 s->here->e_value_size =
591 cpu_to_le32(i->value_len);
592 memset(val + size - EXT4_XATTR_PAD, 0,
593 EXT4_XATTR_PAD); /* Clear pad bytes. */
594 memcpy(val, i->value, i->value_len);
595 return 0;
596 }
597
598 /* Remove the old value. */
599 memmove(first_val + size, first_val, val - first_val);
600 memset(first_val, 0, size);
601 s->here->e_value_size = 0;
602 s->here->e_value_offs = 0;
603 min_offs += size;
604
605 /* Adjust all value offsets. */
606 last = s->first;
607 while (!IS_LAST_ENTRY(last)) {
608 size_t o = le16_to_cpu(last->e_value_offs);
609 if (!last->e_value_block &&
610 last->e_value_size && o < offs)
611 last->e_value_offs =
612 cpu_to_le16(o + size);
613 last = EXT4_XATTR_NEXT(last);
614 }
615 }
616 if (!i->value) {
617 /* Remove the old name. */
618 size_t size = EXT4_XATTR_LEN(name_len);
619 last = ENTRY((void *)last - size);
620 memmove(s->here, (void *)s->here + size,
621 (void *)last - (void *)s->here + sizeof(__u32));
622 memset(last, 0, size);
623 }
624 }
625
626 if (i->value) {
627 /* Insert the new value. */
628 s->here->e_value_size = cpu_to_le32(i->value_len);
629 if (i->value_len) {
630 size_t size = EXT4_XATTR_SIZE(i->value_len);
631 void *val = s->base + min_offs - size;
632 s->here->e_value_offs = cpu_to_le16(min_offs - size);
633 memset(val + size - EXT4_XATTR_PAD, 0,
634 EXT4_XATTR_PAD); /* Clear the pad bytes. */
635 memcpy(val, i->value, i->value_len);
636 }
637 }
638 return 0;
639}
640
641struct ext4_xattr_block_find {
642 struct ext4_xattr_search s;
643 struct buffer_head *bh;
644};
645
646static int
647ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
648 struct ext4_xattr_block_find *bs)
649{
650 struct super_block *sb = inode->i_sb;
651 int error;
652
653 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
654 i->name_index, i->name, i->value, (long)i->value_len);
655
656 if (EXT4_I(inode)->i_file_acl) {
657 /* The inode already has an extended attribute block. */
658 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
659 error = -EIO;
660 if (!bs->bh)
661 goto cleanup;
662 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
663 atomic_read(&(bs->bh->b_count)),
664 le32_to_cpu(BHDR(bs->bh)->h_refcount));
665 if (ext4_xattr_check_block(bs->bh)) {
666 EXT4_ERROR_INODE(inode, "bad block %llu",
667 EXT4_I(inode)->i_file_acl);
668 error = -EIO;
669 goto cleanup;
670 }
671 /* Find the named attribute. */
672 bs->s.base = BHDR(bs->bh);
673 bs->s.first = BFIRST(bs->bh);
674 bs->s.end = bs->bh->b_data + bs->bh->b_size;
675 bs->s.here = bs->s.first;
676 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
677 i->name, bs->bh->b_size, 1);
678 if (error && error != -ENODATA)
679 goto cleanup;
680 bs->s.not_found = error;
681 }
682 error = 0;
683
684cleanup:
685 return error;
686}
687
688static int
689ext4_xattr_block_set(handle_t *handle, struct inode *inode,
690 struct ext4_xattr_info *i,
691 struct ext4_xattr_block_find *bs)
692{
693 struct super_block *sb = inode->i_sb;
694 struct buffer_head *new_bh = NULL;
695 struct ext4_xattr_search *s = &bs->s;
696 struct mb_cache_entry *ce = NULL;
697 int error = 0;
698
699#define header(x) ((struct ext4_xattr_header *)(x))
700
701 if (i->value && i->value_len > sb->s_blocksize)
702 return -ENOSPC;
703 if (s->base) {
704 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
705 bs->bh->b_blocknr);
706 error = ext4_journal_get_write_access(handle, bs->bh);
707 if (error)
708 goto cleanup;
709 lock_buffer(bs->bh);
710
711 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
712 if (ce) {
713 mb_cache_entry_free(ce);
714 ce = NULL;
715 }
716 ea_bdebug(bs->bh, "modifying in-place");
717 error = ext4_xattr_set_entry(i, s);
718 if (!error) {
719 if (!IS_LAST_ENTRY(s->first))
720 ext4_xattr_rehash(header(s->base),
721 s->here);
722 ext4_xattr_cache_insert(bs->bh);
723 }
724 unlock_buffer(bs->bh);
725 if (error == -EIO)
726 goto bad_block;
727 if (!error)
728 error = ext4_handle_dirty_metadata(handle,
729 inode,
730 bs->bh);
731 if (error)
732 goto cleanup;
733 goto inserted;
734 } else {
735 int offset = (char *)s->here - bs->bh->b_data;
736
737 unlock_buffer(bs->bh);
738 ext4_handle_release_buffer(handle, bs->bh);
739 if (ce) {
740 mb_cache_entry_release(ce);
741 ce = NULL;
742 }
743 ea_bdebug(bs->bh, "cloning");
744 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
745 error = -ENOMEM;
746 if (s->base == NULL)
747 goto cleanup;
748 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
749 s->first = ENTRY(header(s->base)+1);
750 header(s->base)->h_refcount = cpu_to_le32(1);
751 s->here = ENTRY(s->base + offset);
752 s->end = s->base + bs->bh->b_size;
753 }
754 } else {
755 /* Allocate a buffer where we construct the new block. */
756 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
757 /* assert(header == s->base) */
758 error = -ENOMEM;
759 if (s->base == NULL)
760 goto cleanup;
761 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
762 header(s->base)->h_blocks = cpu_to_le32(1);
763 header(s->base)->h_refcount = cpu_to_le32(1);
764 s->first = ENTRY(header(s->base)+1);
765 s->here = ENTRY(header(s->base)+1);
766 s->end = s->base + sb->s_blocksize;
767 }
768
769 error = ext4_xattr_set_entry(i, s);
770 if (error == -EIO)
771 goto bad_block;
772 if (error)
773 goto cleanup;
774 if (!IS_LAST_ENTRY(s->first))
775 ext4_xattr_rehash(header(s->base), s->here);
776
777inserted:
778 if (!IS_LAST_ENTRY(s->first)) {
779 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
780 if (new_bh) {
781 /* We found an identical block in the cache. */
782 if (new_bh == bs->bh)
783 ea_bdebug(new_bh, "keeping");
784 else {
785 /* The old block is released after updating
786 the inode. */
787 error = dquot_alloc_block(inode, 1);
788 if (error)
789 goto cleanup;
790 error = ext4_journal_get_write_access(handle,
791 new_bh);
792 if (error)
793 goto cleanup_dquot;
794 lock_buffer(new_bh);
795 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
796 ea_bdebug(new_bh, "reusing; refcount now=%d",
797 le32_to_cpu(BHDR(new_bh)->h_refcount));
798 unlock_buffer(new_bh);
799 error = ext4_handle_dirty_metadata(handle,
800 inode,
801 new_bh);
802 if (error)
803 goto cleanup_dquot;
804 }
805 mb_cache_entry_release(ce);
806 ce = NULL;
807 } else if (bs->bh && s->base == bs->bh->b_data) {
808 /* We were modifying this block in-place. */
809 ea_bdebug(bs->bh, "keeping this block");
810 new_bh = bs->bh;
811 get_bh(new_bh);
812 } else {
813 /* We need to allocate a new block */
814 ext4_fsblk_t goal, block;
815
816 goal = ext4_group_first_block_no(sb,
817 EXT4_I(inode)->i_block_group);
818
819 /* non-extent files can't have physical blocks past 2^32 */
820 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
821 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
822
823 block = ext4_new_meta_blocks(handle, inode, goal, 0,
824 NULL, &error);
825 if (error)
826 goto cleanup;
827
828 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
829 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
830
831 ea_idebug(inode, "creating block %d", block);
832
833 new_bh = sb_getblk(sb, block);
834 if (!new_bh) {
835getblk_failed:
836 ext4_free_blocks(handle, inode, NULL, block, 1,
837 EXT4_FREE_BLOCKS_METADATA);
838 error = -EIO;
839 goto cleanup;
840 }
841 lock_buffer(new_bh);
842 error = ext4_journal_get_create_access(handle, new_bh);
843 if (error) {
844 unlock_buffer(new_bh);
845 goto getblk_failed;
846 }
847 memcpy(new_bh->b_data, s->base, new_bh->b_size);
848 set_buffer_uptodate(new_bh);
849 unlock_buffer(new_bh);
850 ext4_xattr_cache_insert(new_bh);
851 error = ext4_handle_dirty_metadata(handle,
852 inode, new_bh);
853 if (error)
854 goto cleanup;
855 }
856 }
857
858 /* Update the inode. */
859 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
860
861 /* Drop the previous xattr block. */
862 if (bs->bh && bs->bh != new_bh)
863 ext4_xattr_release_block(handle, inode, bs->bh);
864 error = 0;
865
866cleanup:
867 if (ce)
868 mb_cache_entry_release(ce);
869 brelse(new_bh);
870 if (!(bs->bh && s->base == bs->bh->b_data))
871 kfree(s->base);
872
873 return error;
874
875cleanup_dquot:
876 dquot_free_block(inode, 1);
877 goto cleanup;
878
879bad_block:
880 EXT4_ERROR_INODE(inode, "bad block %llu",
881 EXT4_I(inode)->i_file_acl);
882 goto cleanup;
883
884#undef header
885}
886
887struct ext4_xattr_ibody_find {
888 struct ext4_xattr_search s;
889 struct ext4_iloc iloc;
890};
891
892static int
893ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
894 struct ext4_xattr_ibody_find *is)
895{
896 struct ext4_xattr_ibody_header *header;
897 struct ext4_inode *raw_inode;
898 int error;
899
900 if (EXT4_I(inode)->i_extra_isize == 0)
901 return 0;
902 raw_inode = ext4_raw_inode(&is->iloc);
903 header = IHDR(inode, raw_inode);
904 is->s.base = is->s.first = IFIRST(header);
905 is->s.here = is->s.first;
906 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
907 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
908 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
909 if (error)
910 return error;
911 /* Find the named attribute. */
912 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
913 i->name, is->s.end -
914 (void *)is->s.base, 0);
915 if (error && error != -ENODATA)
916 return error;
917 is->s.not_found = error;
918 }
919 return 0;
920}
921
922static int
923ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
924 struct ext4_xattr_info *i,
925 struct ext4_xattr_ibody_find *is)
926{
927 struct ext4_xattr_ibody_header *header;
928 struct ext4_xattr_search *s = &is->s;
929 int error;
930
931 if (EXT4_I(inode)->i_extra_isize == 0)
932 return -ENOSPC;
933 error = ext4_xattr_set_entry(i, s);
934 if (error)
935 return error;
936 header = IHDR(inode, ext4_raw_inode(&is->iloc));
937 if (!IS_LAST_ENTRY(s->first)) {
938 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
939 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
940 } else {
941 header->h_magic = cpu_to_le32(0);
942 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
943 }
944 return 0;
945}
946
947/*
948 * ext4_xattr_set_handle()
949 *
950 * Create, replace or remove an extended attribute for this inode. Value
951 * is NULL to remove an existing extended attribute, and non-NULL to
952 * either replace an existing extended attribute, or create a new extended
953 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
954 * specify that an extended attribute must exist and must not exist
955 * previous to the call, respectively.
956 *
957 * Returns 0, or a negative error number on failure.
958 */
959int
960ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
961 const char *name, const void *value, size_t value_len,
962 int flags)
963{
964 struct ext4_xattr_info i = {
965 .name_index = name_index,
966 .name = name,
967 .value = value,
968 .value_len = value_len,
969
970 };
971 struct ext4_xattr_ibody_find is = {
972 .s = { .not_found = -ENODATA, },
973 };
974 struct ext4_xattr_block_find bs = {
975 .s = { .not_found = -ENODATA, },
976 };
977 unsigned long no_expand;
978 int error;
979
980 if (!name)
981 return -EINVAL;
982 if (strlen(name) > 255)
983 return -ERANGE;
984 down_write(&EXT4_I(inode)->xattr_sem);
985 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
986 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
987
988 error = ext4_get_inode_loc(inode, &is.iloc);
989 if (error)
990 goto cleanup;
991
992 error = ext4_journal_get_write_access(handle, is.iloc.bh);
993 if (error)
994 goto cleanup;
995
996 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
997 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
998 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
999 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1000 }
1001
1002 error = ext4_xattr_ibody_find(inode, &i, &is);
1003 if (error)
1004 goto cleanup;
1005 if (is.s.not_found)
1006 error = ext4_xattr_block_find(inode, &i, &bs);
1007 if (error)
1008 goto cleanup;
1009 if (is.s.not_found && bs.s.not_found) {
1010 error = -ENODATA;
1011 if (flags & XATTR_REPLACE)
1012 goto cleanup;
1013 error = 0;
1014 if (!value)
1015 goto cleanup;
1016 } else {
1017 error = -EEXIST;
1018 if (flags & XATTR_CREATE)
1019 goto cleanup;
1020 }
1021 if (!value) {
1022 if (!is.s.not_found)
1023 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1024 else if (!bs.s.not_found)
1025 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1026 } else {
1027 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1028 if (!error && !bs.s.not_found) {
1029 i.value = NULL;
1030 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1031 } else if (error == -ENOSPC) {
1032 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1033 error = ext4_xattr_block_find(inode, &i, &bs);
1034 if (error)
1035 goto cleanup;
1036 }
1037 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1038 if (error)
1039 goto cleanup;
1040 if (!is.s.not_found) {
1041 i.value = NULL;
1042 error = ext4_xattr_ibody_set(handle, inode, &i,
1043 &is);
1044 }
1045 }
1046 }
1047 if (!error) {
1048 ext4_xattr_update_super_block(handle, inode->i_sb);
1049 inode->i_ctime = ext4_current_time(inode);
1050 if (!value)
1051 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1052 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1053 /*
1054 * The bh is consumed by ext4_mark_iloc_dirty, even with
1055 * error != 0.
1056 */
1057 is.iloc.bh = NULL;
1058 if (IS_SYNC(inode))
1059 ext4_handle_sync(handle);
1060 }
1061
1062cleanup:
1063 brelse(is.iloc.bh);
1064 brelse(bs.bh);
1065 if (no_expand == 0)
1066 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1067 up_write(&EXT4_I(inode)->xattr_sem);
1068 return error;
1069}
1070
1071/*
1072 * ext4_xattr_set()
1073 *
1074 * Like ext4_xattr_set_handle, but start from an inode. This extended
1075 * attribute modification is a filesystem transaction by itself.
1076 *
1077 * Returns 0, or a negative error number on failure.
1078 */
1079int
1080ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1081 const void *value, size_t value_len, int flags)
1082{
1083 handle_t *handle;
1084 int error, retries = 0;
1085
1086retry:
1087 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1088 if (IS_ERR(handle)) {
1089 error = PTR_ERR(handle);
1090 } else {
1091 int error2;
1092
1093 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1094 value, value_len, flags);
1095 error2 = ext4_journal_stop(handle);
1096 if (error == -ENOSPC &&
1097 ext4_should_retry_alloc(inode->i_sb, &retries))
1098 goto retry;
1099 if (error == 0)
1100 error = error2;
1101 }
1102
1103 return error;
1104}
1105
1106/*
1107 * Shift the EA entries in the inode to create space for the increased
1108 * i_extra_isize.
1109 */
1110static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1111 int value_offs_shift, void *to,
1112 void *from, size_t n, int blocksize)
1113{
1114 struct ext4_xattr_entry *last = entry;
1115 int new_offs;
1116
1117 /* Adjust the value offsets of the entries */
1118 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1119 if (!last->e_value_block && last->e_value_size) {
1120 new_offs = le16_to_cpu(last->e_value_offs) +
1121 value_offs_shift;
1122 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1123 > blocksize);
1124 last->e_value_offs = cpu_to_le16(new_offs);
1125 }
1126 }
1127 /* Shift the entries by n bytes */
1128 memmove(to, from, n);
1129}
1130
1131/*
1132 * Expand an inode by new_extra_isize bytes when EAs are present.
1133 * Returns 0 on success or negative error number on failure.
1134 */
1135int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1136 struct ext4_inode *raw_inode, handle_t *handle)
1137{
1138 struct ext4_xattr_ibody_header *header;
1139 struct ext4_xattr_entry *entry, *last, *first;
1140 struct buffer_head *bh = NULL;
1141 struct ext4_xattr_ibody_find *is = NULL;
1142 struct ext4_xattr_block_find *bs = NULL;
1143 char *buffer = NULL, *b_entry_name = NULL;
1144 size_t min_offs, free;
1145 int total_ino, total_blk;
1146 void *base, *start, *end;
1147 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1148 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1149
1150 down_write(&EXT4_I(inode)->xattr_sem);
1151retry:
1152 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1153 up_write(&EXT4_I(inode)->xattr_sem);
1154 return 0;
1155 }
1156
1157 header = IHDR(inode, raw_inode);
1158 entry = IFIRST(header);
1159
1160 /*
1161 * Check if enough free space is available in the inode to shift the
1162 * entries ahead by new_extra_isize.
1163 */
1164
1165 base = start = entry;
1166 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1167 min_offs = end - base;
1168 last = entry;
1169 total_ino = sizeof(struct ext4_xattr_ibody_header);
1170
1171 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1172 if (free >= new_extra_isize) {
1173 entry = IFIRST(header);
1174 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1175 - new_extra_isize, (void *)raw_inode +
1176 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1177 (void *)header, total_ino,
1178 inode->i_sb->s_blocksize);
1179 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1180 error = 0;
1181 goto cleanup;
1182 }
1183
1184 /*
1185 * Enough free space isn't available in the inode, check if
1186 * EA block can hold new_extra_isize bytes.
1187 */
1188 if (EXT4_I(inode)->i_file_acl) {
1189 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1190 error = -EIO;
1191 if (!bh)
1192 goto cleanup;
1193 if (ext4_xattr_check_block(bh)) {
1194 EXT4_ERROR_INODE(inode, "bad block %llu",
1195 EXT4_I(inode)->i_file_acl);
1196 error = -EIO;
1197 goto cleanup;
1198 }
1199 base = BHDR(bh);
1200 first = BFIRST(bh);
1201 end = bh->b_data + bh->b_size;
1202 min_offs = end - base;
1203 free = ext4_xattr_free_space(first, &min_offs, base,
1204 &total_blk);
1205 if (free < new_extra_isize) {
1206 if (!tried_min_extra_isize && s_min_extra_isize) {
1207 tried_min_extra_isize++;
1208 new_extra_isize = s_min_extra_isize;
1209 brelse(bh);
1210 goto retry;
1211 }
1212 error = -1;
1213 goto cleanup;
1214 }
1215 } else {
1216 free = inode->i_sb->s_blocksize;
1217 }
1218
1219 while (new_extra_isize > 0) {
1220 size_t offs, size, entry_size;
1221 struct ext4_xattr_entry *small_entry = NULL;
1222 struct ext4_xattr_info i = {
1223 .value = NULL,
1224 .value_len = 0,
1225 };
1226 unsigned int total_size; /* EA entry size + value size */
1227 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1228 unsigned int min_total_size = ~0U;
1229
1230 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1231 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1232 if (!is || !bs) {
1233 error = -ENOMEM;
1234 goto cleanup;
1235 }
1236
1237 is->s.not_found = -ENODATA;
1238 bs->s.not_found = -ENODATA;
1239 is->iloc.bh = NULL;
1240 bs->bh = NULL;
1241
1242 last = IFIRST(header);
1243 /* Find the entry best suited to be pushed into EA block */
1244 entry = NULL;
1245 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1246 total_size =
1247 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1248 EXT4_XATTR_LEN(last->e_name_len);
1249 if (total_size <= free && total_size < min_total_size) {
1250 if (total_size < new_extra_isize) {
1251 small_entry = last;
1252 } else {
1253 entry = last;
1254 min_total_size = total_size;
1255 }
1256 }
1257 }
1258
1259 if (entry == NULL) {
1260 if (small_entry) {
1261 entry = small_entry;
1262 } else {
1263 if (!tried_min_extra_isize &&
1264 s_min_extra_isize) {
1265 tried_min_extra_isize++;
1266 new_extra_isize = s_min_extra_isize;
1267 goto retry;
1268 }
1269 error = -1;
1270 goto cleanup;
1271 }
1272 }
1273 offs = le16_to_cpu(entry->e_value_offs);
1274 size = le32_to_cpu(entry->e_value_size);
1275 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1276 i.name_index = entry->e_name_index,
1277 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1278 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1279 if (!buffer || !b_entry_name) {
1280 error = -ENOMEM;
1281 goto cleanup;
1282 }
1283 /* Save the entry name and the entry value */
1284 memcpy(buffer, (void *)IFIRST(header) + offs,
1285 EXT4_XATTR_SIZE(size));
1286 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1287 b_entry_name[entry->e_name_len] = '\0';
1288 i.name = b_entry_name;
1289
1290 error = ext4_get_inode_loc(inode, &is->iloc);
1291 if (error)
1292 goto cleanup;
1293
1294 error = ext4_xattr_ibody_find(inode, &i, is);
1295 if (error)
1296 goto cleanup;
1297
1298 /* Remove the chosen entry from the inode */
1299 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1300 if (error)
1301 goto cleanup;
1302
1303 entry = IFIRST(header);
1304 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1305 shift_bytes = new_extra_isize;
1306 else
1307 shift_bytes = entry_size + size;
1308 /* Adjust the offsets and shift the remaining entries ahead */
1309 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1310 shift_bytes, (void *)raw_inode +
1311 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1312 (void *)header, total_ino - entry_size,
1313 inode->i_sb->s_blocksize);
1314
1315 extra_isize += shift_bytes;
1316 new_extra_isize -= shift_bytes;
1317 EXT4_I(inode)->i_extra_isize = extra_isize;
1318
1319 i.name = b_entry_name;
1320 i.value = buffer;
1321 i.value_len = size;
1322 error = ext4_xattr_block_find(inode, &i, bs);
1323 if (error)
1324 goto cleanup;
1325
1326 /* Add entry which was removed from the inode into the block */
1327 error = ext4_xattr_block_set(handle, inode, &i, bs);
1328 if (error)
1329 goto cleanup;
1330 kfree(b_entry_name);
1331 kfree(buffer);
1332 b_entry_name = NULL;
1333 buffer = NULL;
1334 brelse(is->iloc.bh);
1335 kfree(is);
1336 kfree(bs);
1337 }
1338 brelse(bh);
1339 up_write(&EXT4_I(inode)->xattr_sem);
1340 return 0;
1341
1342cleanup:
1343 kfree(b_entry_name);
1344 kfree(buffer);
1345 if (is)
1346 brelse(is->iloc.bh);
1347 kfree(is);
1348 kfree(bs);
1349 brelse(bh);
1350 up_write(&EXT4_I(inode)->xattr_sem);
1351 return error;
1352}
1353
1354
1355
1356/*
1357 * ext4_xattr_delete_inode()
1358 *
1359 * Free extended attribute resources associated with this inode. This
1360 * is called immediately before an inode is freed. We have exclusive
1361 * access to the inode.
1362 */
1363void
1364ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1365{
1366 struct buffer_head *bh = NULL;
1367
1368 if (!EXT4_I(inode)->i_file_acl)
1369 goto cleanup;
1370 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1371 if (!bh) {
1372 EXT4_ERROR_INODE(inode, "block %llu read error",
1373 EXT4_I(inode)->i_file_acl);
1374 goto cleanup;
1375 }
1376 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1377 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1378 EXT4_ERROR_INODE(inode, "bad block %llu",
1379 EXT4_I(inode)->i_file_acl);
1380 goto cleanup;
1381 }
1382 ext4_xattr_release_block(handle, inode, bh);
1383 EXT4_I(inode)->i_file_acl = 0;
1384
1385cleanup:
1386 brelse(bh);
1387}
1388
1389/*
1390 * ext4_xattr_put_super()
1391 *
1392 * This is called when a file system is unmounted.
1393 */
1394void
1395ext4_xattr_put_super(struct super_block *sb)
1396{
1397 mb_cache_shrink(sb->s_bdev);
1398}
1399
1400/*
1401 * ext4_xattr_cache_insert()
1402 *
1403 * Create a new entry in the extended attribute cache, and insert
1404 * it unless such an entry is already in the cache.
1405 *
1406 * Returns 0, or a negative error number on failure.
1407 */
1408static void
1409ext4_xattr_cache_insert(struct buffer_head *bh)
1410{
1411 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1412 struct mb_cache_entry *ce;
1413 int error;
1414
1415 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1416 if (!ce) {
1417 ea_bdebug(bh, "out of memory");
1418 return;
1419 }
1420 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1421 if (error) {
1422 mb_cache_entry_free(ce);
1423 if (error == -EBUSY) {
1424 ea_bdebug(bh, "already in cache");
1425 error = 0;
1426 }
1427 } else {
1428 ea_bdebug(bh, "inserting [%x]", (int)hash);
1429 mb_cache_entry_release(ce);
1430 }
1431}
1432
1433/*
1434 * ext4_xattr_cmp()
1435 *
1436 * Compare two extended attribute blocks for equality.
1437 *
1438 * Returns 0 if the blocks are equal, 1 if they differ, and
1439 * a negative error number on errors.
1440 */
1441static int
1442ext4_xattr_cmp(struct ext4_xattr_header *header1,
1443 struct ext4_xattr_header *header2)
1444{
1445 struct ext4_xattr_entry *entry1, *entry2;
1446
1447 entry1 = ENTRY(header1+1);
1448 entry2 = ENTRY(header2+1);
1449 while (!IS_LAST_ENTRY(entry1)) {
1450 if (IS_LAST_ENTRY(entry2))
1451 return 1;
1452 if (entry1->e_hash != entry2->e_hash ||
1453 entry1->e_name_index != entry2->e_name_index ||
1454 entry1->e_name_len != entry2->e_name_len ||
1455 entry1->e_value_size != entry2->e_value_size ||
1456 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1457 return 1;
1458 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1459 return -EIO;
1460 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1461 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1462 le32_to_cpu(entry1->e_value_size)))
1463 return 1;
1464
1465 entry1 = EXT4_XATTR_NEXT(entry1);
1466 entry2 = EXT4_XATTR_NEXT(entry2);
1467 }
1468 if (!IS_LAST_ENTRY(entry2))
1469 return 1;
1470 return 0;
1471}
1472
1473/*
1474 * ext4_xattr_cache_find()
1475 *
1476 * Find an identical extended attribute block.
1477 *
1478 * Returns a pointer to the block found, or NULL if such a block was
1479 * not found or an error occurred.
1480 */
1481static struct buffer_head *
1482ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1483 struct mb_cache_entry **pce)
1484{
1485 __u32 hash = le32_to_cpu(header->h_hash);
1486 struct mb_cache_entry *ce;
1487
1488 if (!header->h_hash)
1489 return NULL; /* never share */
1490 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1491again:
1492 ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1493 hash);
1494 while (ce) {
1495 struct buffer_head *bh;
1496
1497 if (IS_ERR(ce)) {
1498 if (PTR_ERR(ce) == -EAGAIN)
1499 goto again;
1500 break;
1501 }
1502 bh = sb_bread(inode->i_sb, ce->e_block);
1503 if (!bh) {
1504 EXT4_ERROR_INODE(inode, "block %lu read error",
1505 (unsigned long) ce->e_block);
1506 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1507 EXT4_XATTR_REFCOUNT_MAX) {
1508 ea_idebug(inode, "block %lu refcount %d>=%d",
1509 (unsigned long) ce->e_block,
1510 le32_to_cpu(BHDR(bh)->h_refcount),
1511 EXT4_XATTR_REFCOUNT_MAX);
1512 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1513 *pce = ce;
1514 return bh;
1515 }
1516 brelse(bh);
1517 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1518 }
1519 return NULL;
1520}
1521
1522#define NAME_HASH_SHIFT 5
1523#define VALUE_HASH_SHIFT 16
1524
1525/*
1526 * ext4_xattr_hash_entry()
1527 *
1528 * Compute the hash of an extended attribute.
1529 */
1530static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1531 struct ext4_xattr_entry *entry)
1532{
1533 __u32 hash = 0;
1534 char *name = entry->e_name;
1535 int n;
1536
1537 for (n = 0; n < entry->e_name_len; n++) {
1538 hash = (hash << NAME_HASH_SHIFT) ^
1539 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1540 *name++;
1541 }
1542
1543 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1544 __le32 *value = (__le32 *)((char *)header +
1545 le16_to_cpu(entry->e_value_offs));
1546 for (n = (le32_to_cpu(entry->e_value_size) +
1547 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1548 hash = (hash << VALUE_HASH_SHIFT) ^
1549 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1550 le32_to_cpu(*value++);
1551 }
1552 }
1553 entry->e_hash = cpu_to_le32(hash);
1554}
1555
1556#undef NAME_HASH_SHIFT
1557#undef VALUE_HASH_SHIFT
1558
1559#define BLOCK_HASH_SHIFT 16
1560
1561/*
1562 * ext4_xattr_rehash()
1563 *
1564 * Re-compute the extended attribute hash value after an entry has changed.
1565 */
1566static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1567 struct ext4_xattr_entry *entry)
1568{
1569 struct ext4_xattr_entry *here;
1570 __u32 hash = 0;
1571
1572 ext4_xattr_hash_entry(header, entry);
1573 here = ENTRY(header+1);
1574 while (!IS_LAST_ENTRY(here)) {
1575 if (!here->e_hash) {
1576 /* Block is not shared if an entry's hash value == 0 */
1577 hash = 0;
1578 break;
1579 }
1580 hash = (hash << BLOCK_HASH_SHIFT) ^
1581 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1582 le32_to_cpu(here->e_hash);
1583 here = EXT4_XATTR_NEXT(here);
1584 }
1585 header->h_hash = cpu_to_le32(hash);
1586}
1587
1588#undef BLOCK_HASH_SHIFT
1589
1590int __init
1591ext4_init_xattr(void)
1592{
1593 ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1594 if (!ext4_xattr_cache)
1595 return -ENOMEM;
1596 return 0;
1597}
1598
1599void
1600ext4_exit_xattr(void)
1601{
1602 if (ext4_xattr_cache)
1603 mb_cache_destroy(ext4_xattr_cache);
1604 ext4_xattr_cache = NULL;
1605}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/xattr.c
4 *
5 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
6 *
7 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
8 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
9 * Extended attributes for symlinks and special files added per
10 * suggestion of Luka Renko <luka.renko@hermes.si>.
11 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
12 * Red Hat Inc.
13 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
14 * and Andreas Gruenbacher <agruen@suse.de>.
15 */
16
17/*
18 * Extended attributes are stored directly in inodes (on file systems with
19 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
20 * field contains the block number if an inode uses an additional block. All
21 * attributes must fit in the inode and one additional block. Blocks that
22 * contain the identical set of attributes may be shared among several inodes.
23 * Identical blocks are detected by keeping a cache of blocks that have
24 * recently been accessed.
25 *
26 * The attributes in inodes and on blocks have a different header; the entries
27 * are stored in the same format:
28 *
29 * +------------------+
30 * | header |
31 * | entry 1 | |
32 * | entry 2 | | growing downwards
33 * | entry 3 | v
34 * | four null bytes |
35 * | . . . |
36 * | value 1 | ^
37 * | value 3 | | growing upwards
38 * | value 2 | |
39 * +------------------+
40 *
41 * The header is followed by multiple entry descriptors. In disk blocks, the
42 * entry descriptors are kept sorted. In inodes, they are unsorted. The
43 * attribute values are aligned to the end of the block in no specific order.
44 *
45 * Locking strategy
46 * ----------------
47 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
48 * EA blocks are only changed if they are exclusive to an inode, so
49 * holding xattr_sem also means that nothing but the EA block's reference
50 * count can change. Multiple writers to the same block are synchronized
51 * by the buffer lock.
52 */
53
54#include <linux/init.h>
55#include <linux/fs.h>
56#include <linux/slab.h>
57#include <linux/mbcache.h>
58#include <linux/quotaops.h>
59#include <linux/iversion.h>
60#include "ext4_jbd2.h"
61#include "ext4.h"
62#include "xattr.h"
63#include "acl.h"
64
65#ifdef EXT4_XATTR_DEBUG
66# define ea_idebug(inode, fmt, ...) \
67 printk(KERN_DEBUG "inode %s:%lu: " fmt "\n", \
68 inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
69# define ea_bdebug(bh, fmt, ...) \
70 printk(KERN_DEBUG "block %pg:%lu: " fmt "\n", \
71 bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
72#else
73# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
74# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
75#endif
76
77static void ext4_xattr_block_cache_insert(struct mb_cache *,
78 struct buffer_head *);
79static struct buffer_head *
80ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
81 struct mb_cache_entry **);
82static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
83 size_t value_count);
84static void ext4_xattr_rehash(struct ext4_xattr_header *);
85
86static const struct xattr_handler * const ext4_xattr_handler_map[] = {
87 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
88#ifdef CONFIG_EXT4_FS_POSIX_ACL
89 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
90 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
91#endif
92 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
93#ifdef CONFIG_EXT4_FS_SECURITY
94 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
95#endif
96};
97
98const struct xattr_handler *ext4_xattr_handlers[] = {
99 &ext4_xattr_user_handler,
100 &ext4_xattr_trusted_handler,
101#ifdef CONFIG_EXT4_FS_POSIX_ACL
102 &posix_acl_access_xattr_handler,
103 &posix_acl_default_xattr_handler,
104#endif
105#ifdef CONFIG_EXT4_FS_SECURITY
106 &ext4_xattr_security_handler,
107#endif
108 NULL
109};
110
111#define EA_BLOCK_CACHE(inode) (((struct ext4_sb_info *) \
112 inode->i_sb->s_fs_info)->s_ea_block_cache)
113
114#define EA_INODE_CACHE(inode) (((struct ext4_sb_info *) \
115 inode->i_sb->s_fs_info)->s_ea_inode_cache)
116
117static int
118ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
119 struct inode *inode);
120
121#ifdef CONFIG_LOCKDEP
122void ext4_xattr_inode_set_class(struct inode *ea_inode)
123{
124 lockdep_set_subclass(&ea_inode->i_rwsem, 1);
125}
126#endif
127
128static __le32 ext4_xattr_block_csum(struct inode *inode,
129 sector_t block_nr,
130 struct ext4_xattr_header *hdr)
131{
132 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
133 __u32 csum;
134 __le64 dsk_block_nr = cpu_to_le64(block_nr);
135 __u32 dummy_csum = 0;
136 int offset = offsetof(struct ext4_xattr_header, h_checksum);
137
138 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
139 sizeof(dsk_block_nr));
140 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
141 csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
142 offset += sizeof(dummy_csum);
143 csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
144 EXT4_BLOCK_SIZE(inode->i_sb) - offset);
145
146 return cpu_to_le32(csum);
147}
148
149static int ext4_xattr_block_csum_verify(struct inode *inode,
150 struct buffer_head *bh)
151{
152 struct ext4_xattr_header *hdr = BHDR(bh);
153 int ret = 1;
154
155 if (ext4_has_metadata_csum(inode->i_sb)) {
156 lock_buffer(bh);
157 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
158 bh->b_blocknr, hdr));
159 unlock_buffer(bh);
160 }
161 return ret;
162}
163
164static void ext4_xattr_block_csum_set(struct inode *inode,
165 struct buffer_head *bh)
166{
167 if (ext4_has_metadata_csum(inode->i_sb))
168 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
169 bh->b_blocknr, BHDR(bh));
170}
171
172static inline const struct xattr_handler *
173ext4_xattr_handler(int name_index)
174{
175 const struct xattr_handler *handler = NULL;
176
177 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
178 handler = ext4_xattr_handler_map[name_index];
179 return handler;
180}
181
182static int
183ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
184 void *value_start)
185{
186 struct ext4_xattr_entry *e = entry;
187
188 /* Find the end of the names list */
189 while (!IS_LAST_ENTRY(e)) {
190 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
191 if ((void *)next >= end)
192 return -EFSCORRUPTED;
193 if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
194 return -EFSCORRUPTED;
195 e = next;
196 }
197
198 /* Check the values */
199 while (!IS_LAST_ENTRY(entry)) {
200 u32 size = le32_to_cpu(entry->e_value_size);
201
202 if (size > EXT4_XATTR_SIZE_MAX)
203 return -EFSCORRUPTED;
204
205 if (size != 0 && entry->e_value_inum == 0) {
206 u16 offs = le16_to_cpu(entry->e_value_offs);
207 void *value;
208
209 /*
210 * The value cannot overlap the names, and the value
211 * with padding cannot extend beyond 'end'. Check both
212 * the padded and unpadded sizes, since the size may
213 * overflow to 0 when adding padding.
214 */
215 if (offs > end - value_start)
216 return -EFSCORRUPTED;
217 value = value_start + offs;
218 if (value < (void *)e + sizeof(u32) ||
219 size > end - value ||
220 EXT4_XATTR_SIZE(size) > end - value)
221 return -EFSCORRUPTED;
222 }
223 entry = EXT4_XATTR_NEXT(entry);
224 }
225
226 return 0;
227}
228
229static inline int
230__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
231 const char *function, unsigned int line)
232{
233 int error = -EFSCORRUPTED;
234
235 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
236 BHDR(bh)->h_blocks != cpu_to_le32(1))
237 goto errout;
238 if (buffer_verified(bh))
239 return 0;
240
241 error = -EFSBADCRC;
242 if (!ext4_xattr_block_csum_verify(inode, bh))
243 goto errout;
244 error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
245 bh->b_data);
246errout:
247 if (error)
248 __ext4_error_inode(inode, function, line, 0,
249 "corrupted xattr block %llu",
250 (unsigned long long) bh->b_blocknr);
251 else
252 set_buffer_verified(bh);
253 return error;
254}
255
256#define ext4_xattr_check_block(inode, bh) \
257 __ext4_xattr_check_block((inode), (bh), __func__, __LINE__)
258
259
260static int
261__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
262 void *end, const char *function, unsigned int line)
263{
264 int error = -EFSCORRUPTED;
265
266 if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
267 (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
268 goto errout;
269 error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
270errout:
271 if (error)
272 __ext4_error_inode(inode, function, line, 0,
273 "corrupted in-inode xattr");
274 return error;
275}
276
277#define xattr_check_inode(inode, header, end) \
278 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
279
280static int
281xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
282 void *end, int name_index, const char *name, int sorted)
283{
284 struct ext4_xattr_entry *entry, *next;
285 size_t name_len;
286 int cmp = 1;
287
288 if (name == NULL)
289 return -EINVAL;
290 name_len = strlen(name);
291 for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
292 next = EXT4_XATTR_NEXT(entry);
293 if ((void *) next >= end) {
294 EXT4_ERROR_INODE(inode, "corrupted xattr entries");
295 return -EFSCORRUPTED;
296 }
297 cmp = name_index - entry->e_name_index;
298 if (!cmp)
299 cmp = name_len - entry->e_name_len;
300 if (!cmp)
301 cmp = memcmp(name, entry->e_name, name_len);
302 if (cmp <= 0 && (sorted || cmp == 0))
303 break;
304 }
305 *pentry = entry;
306 return cmp ? -ENODATA : 0;
307}
308
309static u32
310ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
311{
312 return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
313}
314
315static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
316{
317 return ((u64)ea_inode->i_ctime.tv_sec << 32) |
318 (u32) inode_peek_iversion_raw(ea_inode);
319}
320
321static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
322{
323 ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
324 inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
325}
326
327static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
328{
329 return (u32)ea_inode->i_atime.tv_sec;
330}
331
332static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
333{
334 ea_inode->i_atime.tv_sec = hash;
335}
336
337/*
338 * Read the EA value from an inode.
339 */
340static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
341{
342 int blocksize = 1 << ea_inode->i_blkbits;
343 int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
344 int tail_size = (size % blocksize) ?: blocksize;
345 struct buffer_head *bhs_inline[8];
346 struct buffer_head **bhs = bhs_inline;
347 int i, ret;
348
349 if (bh_count > ARRAY_SIZE(bhs_inline)) {
350 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
351 if (!bhs)
352 return -ENOMEM;
353 }
354
355 ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
356 true /* wait */, bhs);
357 if (ret)
358 goto free_bhs;
359
360 for (i = 0; i < bh_count; i++) {
361 /* There shouldn't be any holes in ea_inode. */
362 if (!bhs[i]) {
363 ret = -EFSCORRUPTED;
364 goto put_bhs;
365 }
366 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
367 i < bh_count - 1 ? blocksize : tail_size);
368 }
369 ret = 0;
370put_bhs:
371 for (i = 0; i < bh_count; i++)
372 brelse(bhs[i]);
373free_bhs:
374 if (bhs != bhs_inline)
375 kfree(bhs);
376 return ret;
377}
378
379#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
380
381static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
382 u32 ea_inode_hash, struct inode **ea_inode)
383{
384 struct inode *inode;
385 int err;
386
387 inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
388 if (IS_ERR(inode)) {
389 err = PTR_ERR(inode);
390 ext4_error(parent->i_sb,
391 "error while reading EA inode %lu err=%d", ea_ino,
392 err);
393 return err;
394 }
395
396 if (is_bad_inode(inode)) {
397 ext4_error(parent->i_sb,
398 "error while reading EA inode %lu is_bad_inode",
399 ea_ino);
400 err = -EIO;
401 goto error;
402 }
403
404 if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
405 ext4_error(parent->i_sb,
406 "EA inode %lu does not have EXT4_EA_INODE_FL flag",
407 ea_ino);
408 err = -EINVAL;
409 goto error;
410 }
411
412 ext4_xattr_inode_set_class(inode);
413
414 /*
415 * Check whether this is an old Lustre-style xattr inode. Lustre
416 * implementation does not have hash validation, rather it has a
417 * backpointer from ea_inode to the parent inode.
418 */
419 if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
420 EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
421 inode->i_generation == parent->i_generation) {
422 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
423 ext4_xattr_inode_set_ref(inode, 1);
424 } else {
425 inode_lock(inode);
426 inode->i_flags |= S_NOQUOTA;
427 inode_unlock(inode);
428 }
429
430 *ea_inode = inode;
431 return 0;
432error:
433 iput(inode);
434 return err;
435}
436
437static int
438ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
439 struct ext4_xattr_entry *entry, void *buffer,
440 size_t size)
441{
442 u32 hash;
443
444 /* Verify stored hash matches calculated hash. */
445 hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
446 if (hash != ext4_xattr_inode_get_hash(ea_inode))
447 return -EFSCORRUPTED;
448
449 if (entry) {
450 __le32 e_hash, tmp_data;
451
452 /* Verify entry hash. */
453 tmp_data = cpu_to_le32(hash);
454 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
455 &tmp_data, 1);
456 if (e_hash != entry->e_hash)
457 return -EFSCORRUPTED;
458 }
459 return 0;
460}
461
462/*
463 * Read xattr value from the EA inode.
464 */
465static int
466ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
467 void *buffer, size_t size)
468{
469 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
470 struct inode *ea_inode;
471 int err;
472
473 err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
474 le32_to_cpu(entry->e_hash), &ea_inode);
475 if (err) {
476 ea_inode = NULL;
477 goto out;
478 }
479
480 if (i_size_read(ea_inode) != size) {
481 ext4_warning_inode(ea_inode,
482 "ea_inode file size=%llu entry size=%zu",
483 i_size_read(ea_inode), size);
484 err = -EFSCORRUPTED;
485 goto out;
486 }
487
488 err = ext4_xattr_inode_read(ea_inode, buffer, size);
489 if (err)
490 goto out;
491
492 if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
493 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
494 size);
495 if (err) {
496 ext4_warning_inode(ea_inode,
497 "EA inode hash validation failed");
498 goto out;
499 }
500
501 if (ea_inode_cache)
502 mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
503 ext4_xattr_inode_get_hash(ea_inode),
504 ea_inode->i_ino, true /* reusable */);
505 }
506out:
507 iput(ea_inode);
508 return err;
509}
510
511static int
512ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
513 void *buffer, size_t buffer_size)
514{
515 struct buffer_head *bh = NULL;
516 struct ext4_xattr_entry *entry;
517 size_t size;
518 void *end;
519 int error;
520 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
521
522 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
523 name_index, name, buffer, (long)buffer_size);
524
525 if (!EXT4_I(inode)->i_file_acl)
526 return -ENODATA;
527 ea_idebug(inode, "reading block %llu",
528 (unsigned long long)EXT4_I(inode)->i_file_acl);
529 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
530 if (IS_ERR(bh))
531 return PTR_ERR(bh);
532 ea_bdebug(bh, "b_count=%d, refcount=%d",
533 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
534 error = ext4_xattr_check_block(inode, bh);
535 if (error)
536 goto cleanup;
537 ext4_xattr_block_cache_insert(ea_block_cache, bh);
538 entry = BFIRST(bh);
539 end = bh->b_data + bh->b_size;
540 error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
541 if (error)
542 goto cleanup;
543 size = le32_to_cpu(entry->e_value_size);
544 error = -ERANGE;
545 if (unlikely(size > EXT4_XATTR_SIZE_MAX))
546 goto cleanup;
547 if (buffer) {
548 if (size > buffer_size)
549 goto cleanup;
550 if (entry->e_value_inum) {
551 error = ext4_xattr_inode_get(inode, entry, buffer,
552 size);
553 if (error)
554 goto cleanup;
555 } else {
556 u16 offset = le16_to_cpu(entry->e_value_offs);
557 void *p = bh->b_data + offset;
558
559 if (unlikely(p + size > end))
560 goto cleanup;
561 memcpy(buffer, p, size);
562 }
563 }
564 error = size;
565
566cleanup:
567 brelse(bh);
568 return error;
569}
570
571int
572ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
573 void *buffer, size_t buffer_size)
574{
575 struct ext4_xattr_ibody_header *header;
576 struct ext4_xattr_entry *entry;
577 struct ext4_inode *raw_inode;
578 struct ext4_iloc iloc;
579 size_t size;
580 void *end;
581 int error;
582
583 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
584 return -ENODATA;
585 error = ext4_get_inode_loc(inode, &iloc);
586 if (error)
587 return error;
588 raw_inode = ext4_raw_inode(&iloc);
589 header = IHDR(inode, raw_inode);
590 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
591 error = xattr_check_inode(inode, header, end);
592 if (error)
593 goto cleanup;
594 entry = IFIRST(header);
595 error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
596 if (error)
597 goto cleanup;
598 size = le32_to_cpu(entry->e_value_size);
599 error = -ERANGE;
600 if (unlikely(size > EXT4_XATTR_SIZE_MAX))
601 goto cleanup;
602 if (buffer) {
603 if (size > buffer_size)
604 goto cleanup;
605 if (entry->e_value_inum) {
606 error = ext4_xattr_inode_get(inode, entry, buffer,
607 size);
608 if (error)
609 goto cleanup;
610 } else {
611 u16 offset = le16_to_cpu(entry->e_value_offs);
612 void *p = (void *)IFIRST(header) + offset;
613
614 if (unlikely(p + size > end))
615 goto cleanup;
616 memcpy(buffer, p, size);
617 }
618 }
619 error = size;
620
621cleanup:
622 brelse(iloc.bh);
623 return error;
624}
625
626/*
627 * ext4_xattr_get()
628 *
629 * Copy an extended attribute into the buffer
630 * provided, or compute the buffer size required.
631 * Buffer is NULL to compute the size of the buffer required.
632 *
633 * Returns a negative error number on failure, or the number of bytes
634 * used / required on success.
635 */
636int
637ext4_xattr_get(struct inode *inode, int name_index, const char *name,
638 void *buffer, size_t buffer_size)
639{
640 int error;
641
642 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
643 return -EIO;
644
645 if (strlen(name) > 255)
646 return -ERANGE;
647
648 down_read(&EXT4_I(inode)->xattr_sem);
649 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
650 buffer_size);
651 if (error == -ENODATA)
652 error = ext4_xattr_block_get(inode, name_index, name, buffer,
653 buffer_size);
654 up_read(&EXT4_I(inode)->xattr_sem);
655 return error;
656}
657
658static int
659ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
660 char *buffer, size_t buffer_size)
661{
662 size_t rest = buffer_size;
663
664 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
665 const struct xattr_handler *handler =
666 ext4_xattr_handler(entry->e_name_index);
667
668 if (handler && (!handler->list || handler->list(dentry))) {
669 const char *prefix = handler->prefix ?: handler->name;
670 size_t prefix_len = strlen(prefix);
671 size_t size = prefix_len + entry->e_name_len + 1;
672
673 if (buffer) {
674 if (size > rest)
675 return -ERANGE;
676 memcpy(buffer, prefix, prefix_len);
677 buffer += prefix_len;
678 memcpy(buffer, entry->e_name, entry->e_name_len);
679 buffer += entry->e_name_len;
680 *buffer++ = 0;
681 }
682 rest -= size;
683 }
684 }
685 return buffer_size - rest; /* total size */
686}
687
688static int
689ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
690{
691 struct inode *inode = d_inode(dentry);
692 struct buffer_head *bh = NULL;
693 int error;
694
695 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
696 buffer, (long)buffer_size);
697
698 if (!EXT4_I(inode)->i_file_acl)
699 return 0;
700 ea_idebug(inode, "reading block %llu",
701 (unsigned long long)EXT4_I(inode)->i_file_acl);
702 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
703 if (IS_ERR(bh))
704 return PTR_ERR(bh);
705 ea_bdebug(bh, "b_count=%d, refcount=%d",
706 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
707 error = ext4_xattr_check_block(inode, bh);
708 if (error)
709 goto cleanup;
710 ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
711 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
712 buffer_size);
713cleanup:
714 brelse(bh);
715 return error;
716}
717
718static int
719ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
720{
721 struct inode *inode = d_inode(dentry);
722 struct ext4_xattr_ibody_header *header;
723 struct ext4_inode *raw_inode;
724 struct ext4_iloc iloc;
725 void *end;
726 int error;
727
728 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
729 return 0;
730 error = ext4_get_inode_loc(inode, &iloc);
731 if (error)
732 return error;
733 raw_inode = ext4_raw_inode(&iloc);
734 header = IHDR(inode, raw_inode);
735 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
736 error = xattr_check_inode(inode, header, end);
737 if (error)
738 goto cleanup;
739 error = ext4_xattr_list_entries(dentry, IFIRST(header),
740 buffer, buffer_size);
741
742cleanup:
743 brelse(iloc.bh);
744 return error;
745}
746
747/*
748 * Inode operation listxattr()
749 *
750 * d_inode(dentry)->i_rwsem: don't care
751 *
752 * Copy a list of attribute names into the buffer
753 * provided, or compute the buffer size required.
754 * Buffer is NULL to compute the size of the buffer required.
755 *
756 * Returns a negative error number on failure, or the number of bytes
757 * used / required on success.
758 */
759ssize_t
760ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
761{
762 int ret, ret2;
763
764 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
765 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
766 if (ret < 0)
767 goto errout;
768 if (buffer) {
769 buffer += ret;
770 buffer_size -= ret;
771 }
772 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
773 if (ret < 0)
774 goto errout;
775 ret += ret2;
776errout:
777 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
778 return ret;
779}
780
781/*
782 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
783 * not set, set it.
784 */
785static void ext4_xattr_update_super_block(handle_t *handle,
786 struct super_block *sb)
787{
788 if (ext4_has_feature_xattr(sb))
789 return;
790
791 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
792 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
793 ext4_set_feature_xattr(sb);
794 ext4_handle_dirty_super(handle, sb);
795 }
796}
797
798int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
799{
800 struct ext4_iloc iloc = { .bh = NULL };
801 struct buffer_head *bh = NULL;
802 struct ext4_inode *raw_inode;
803 struct ext4_xattr_ibody_header *header;
804 struct ext4_xattr_entry *entry;
805 qsize_t ea_inode_refs = 0;
806 void *end;
807 int ret;
808
809 lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
810
811 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
812 ret = ext4_get_inode_loc(inode, &iloc);
813 if (ret)
814 goto out;
815 raw_inode = ext4_raw_inode(&iloc);
816 header = IHDR(inode, raw_inode);
817 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
818 ret = xattr_check_inode(inode, header, end);
819 if (ret)
820 goto out;
821
822 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
823 entry = EXT4_XATTR_NEXT(entry))
824 if (entry->e_value_inum)
825 ea_inode_refs++;
826 }
827
828 if (EXT4_I(inode)->i_file_acl) {
829 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
830 if (IS_ERR(bh)) {
831 ret = PTR_ERR(bh);
832 bh = NULL;
833 goto out;
834 }
835
836 ret = ext4_xattr_check_block(inode, bh);
837 if (ret)
838 goto out;
839
840 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
841 entry = EXT4_XATTR_NEXT(entry))
842 if (entry->e_value_inum)
843 ea_inode_refs++;
844 }
845 *usage = ea_inode_refs + 1;
846 ret = 0;
847out:
848 brelse(iloc.bh);
849 brelse(bh);
850 return ret;
851}
852
853static inline size_t round_up_cluster(struct inode *inode, size_t length)
854{
855 struct super_block *sb = inode->i_sb;
856 size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
857 inode->i_blkbits);
858 size_t mask = ~(cluster_size - 1);
859
860 return (length + cluster_size - 1) & mask;
861}
862
863static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
864{
865 int err;
866
867 err = dquot_alloc_inode(inode);
868 if (err)
869 return err;
870 err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
871 if (err)
872 dquot_free_inode(inode);
873 return err;
874}
875
876static void ext4_xattr_inode_free_quota(struct inode *parent,
877 struct inode *ea_inode,
878 size_t len)
879{
880 if (ea_inode &&
881 ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
882 return;
883 dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
884 dquot_free_inode(parent);
885}
886
887int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
888 struct buffer_head *block_bh, size_t value_len,
889 bool is_create)
890{
891 int credits;
892 int blocks;
893
894 /*
895 * 1) Owner inode update
896 * 2) Ref count update on old xattr block
897 * 3) new xattr block
898 * 4) block bitmap update for new xattr block
899 * 5) group descriptor for new xattr block
900 * 6) block bitmap update for old xattr block
901 * 7) group descriptor for old block
902 *
903 * 6 & 7 can happen if we have two racing threads T_a and T_b
904 * which are each trying to set an xattr on inodes I_a and I_b
905 * which were both initially sharing an xattr block.
906 */
907 credits = 7;
908
909 /* Quota updates. */
910 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
911
912 /*
913 * In case of inline data, we may push out the data to a block,
914 * so we need to reserve credits for this eventuality
915 */
916 if (inode && ext4_has_inline_data(inode))
917 credits += ext4_writepage_trans_blocks(inode) + 1;
918
919 /* We are done if ea_inode feature is not enabled. */
920 if (!ext4_has_feature_ea_inode(sb))
921 return credits;
922
923 /* New ea_inode, inode map, block bitmap, group descriptor. */
924 credits += 4;
925
926 /* Data blocks. */
927 blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
928
929 /* Indirection block or one level of extent tree. */
930 blocks += 1;
931
932 /* Block bitmap and group descriptor updates for each block. */
933 credits += blocks * 2;
934
935 /* Blocks themselves. */
936 credits += blocks;
937
938 if (!is_create) {
939 /* Dereference ea_inode holding old xattr value.
940 * Old ea_inode, inode map, block bitmap, group descriptor.
941 */
942 credits += 4;
943
944 /* Data blocks for old ea_inode. */
945 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
946
947 /* Indirection block or one level of extent tree for old
948 * ea_inode.
949 */
950 blocks += 1;
951
952 /* Block bitmap and group descriptor updates for each block. */
953 credits += blocks * 2;
954 }
955
956 /* We may need to clone the existing xattr block in which case we need
957 * to increment ref counts for existing ea_inodes referenced by it.
958 */
959 if (block_bh) {
960 struct ext4_xattr_entry *entry = BFIRST(block_bh);
961
962 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
963 if (entry->e_value_inum)
964 /* Ref count update on ea_inode. */
965 credits += 1;
966 }
967 return credits;
968}
969
970static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
971 int credits, struct buffer_head *bh,
972 bool dirty, bool block_csum)
973{
974 int error;
975
976 if (!ext4_handle_valid(handle))
977 return 0;
978
979 if (handle->h_buffer_credits >= credits)
980 return 0;
981
982 error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);
983 if (!error)
984 return 0;
985 if (error < 0) {
986 ext4_warning(inode->i_sb, "Extend journal (error %d)", error);
987 return error;
988 }
989
990 if (bh && dirty) {
991 if (block_csum)
992 ext4_xattr_block_csum_set(inode, bh);
993 error = ext4_handle_dirty_metadata(handle, NULL, bh);
994 if (error) {
995 ext4_warning(inode->i_sb, "Handle metadata (error %d)",
996 error);
997 return error;
998 }
999 }
1000
1001 error = ext4_journal_restart(handle, credits);
1002 if (error) {
1003 ext4_warning(inode->i_sb, "Restart journal (error %d)", error);
1004 return error;
1005 }
1006
1007 if (bh) {
1008 error = ext4_journal_get_write_access(handle, bh);
1009 if (error) {
1010 ext4_warning(inode->i_sb,
1011 "Get write access failed (error %d)",
1012 error);
1013 return error;
1014 }
1015 }
1016 return 0;
1017}
1018
1019static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
1020 int ref_change)
1021{
1022 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
1023 struct ext4_iloc iloc;
1024 s64 ref_count;
1025 u32 hash;
1026 int ret;
1027
1028 inode_lock(ea_inode);
1029
1030 ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
1031 if (ret)
1032 goto out;
1033
1034 ref_count = ext4_xattr_inode_get_ref(ea_inode);
1035 ref_count += ref_change;
1036 ext4_xattr_inode_set_ref(ea_inode, ref_count);
1037
1038 if (ref_change > 0) {
1039 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1040 ea_inode->i_ino, ref_count);
1041
1042 if (ref_count == 1) {
1043 WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1044 ea_inode->i_ino, ea_inode->i_nlink);
1045
1046 set_nlink(ea_inode, 1);
1047 ext4_orphan_del(handle, ea_inode);
1048
1049 if (ea_inode_cache) {
1050 hash = ext4_xattr_inode_get_hash(ea_inode);
1051 mb_cache_entry_create(ea_inode_cache,
1052 GFP_NOFS, hash,
1053 ea_inode->i_ino,
1054 true /* reusable */);
1055 }
1056 }
1057 } else {
1058 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1059 ea_inode->i_ino, ref_count);
1060
1061 if (ref_count == 0) {
1062 WARN_ONCE(ea_inode->i_nlink != 1,
1063 "EA inode %lu i_nlink=%u",
1064 ea_inode->i_ino, ea_inode->i_nlink);
1065
1066 clear_nlink(ea_inode);
1067 ext4_orphan_add(handle, ea_inode);
1068
1069 if (ea_inode_cache) {
1070 hash = ext4_xattr_inode_get_hash(ea_inode);
1071 mb_cache_entry_delete(ea_inode_cache, hash,
1072 ea_inode->i_ino);
1073 }
1074 }
1075 }
1076
1077 ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1078 if (ret)
1079 ext4_warning_inode(ea_inode,
1080 "ext4_mark_iloc_dirty() failed ret=%d", ret);
1081out:
1082 inode_unlock(ea_inode);
1083 return ret;
1084}
1085
1086static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1087{
1088 return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1089}
1090
1091static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1092{
1093 return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1094}
1095
1096static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1097 struct ext4_xattr_entry *first)
1098{
1099 struct inode *ea_inode;
1100 struct ext4_xattr_entry *entry;
1101 struct ext4_xattr_entry *failed_entry;
1102 unsigned int ea_ino;
1103 int err, saved_err;
1104
1105 for (entry = first; !IS_LAST_ENTRY(entry);
1106 entry = EXT4_XATTR_NEXT(entry)) {
1107 if (!entry->e_value_inum)
1108 continue;
1109 ea_ino = le32_to_cpu(entry->e_value_inum);
1110 err = ext4_xattr_inode_iget(parent, ea_ino,
1111 le32_to_cpu(entry->e_hash),
1112 &ea_inode);
1113 if (err)
1114 goto cleanup;
1115 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1116 if (err) {
1117 ext4_warning_inode(ea_inode, "inc ref error %d", err);
1118 iput(ea_inode);
1119 goto cleanup;
1120 }
1121 iput(ea_inode);
1122 }
1123 return 0;
1124
1125cleanup:
1126 saved_err = err;
1127 failed_entry = entry;
1128
1129 for (entry = first; entry != failed_entry;
1130 entry = EXT4_XATTR_NEXT(entry)) {
1131 if (!entry->e_value_inum)
1132 continue;
1133 ea_ino = le32_to_cpu(entry->e_value_inum);
1134 err = ext4_xattr_inode_iget(parent, ea_ino,
1135 le32_to_cpu(entry->e_hash),
1136 &ea_inode);
1137 if (err) {
1138 ext4_warning(parent->i_sb,
1139 "cleanup ea_ino %u iget error %d", ea_ino,
1140 err);
1141 continue;
1142 }
1143 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1144 if (err)
1145 ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1146 err);
1147 iput(ea_inode);
1148 }
1149 return saved_err;
1150}
1151
1152static void
1153ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1154 struct buffer_head *bh,
1155 struct ext4_xattr_entry *first, bool block_csum,
1156 struct ext4_xattr_inode_array **ea_inode_array,
1157 int extra_credits, bool skip_quota)
1158{
1159 struct inode *ea_inode;
1160 struct ext4_xattr_entry *entry;
1161 bool dirty = false;
1162 unsigned int ea_ino;
1163 int err;
1164 int credits;
1165
1166 /* One credit for dec ref on ea_inode, one for orphan list addition, */
1167 credits = 2 + extra_credits;
1168
1169 for (entry = first; !IS_LAST_ENTRY(entry);
1170 entry = EXT4_XATTR_NEXT(entry)) {
1171 if (!entry->e_value_inum)
1172 continue;
1173 ea_ino = le32_to_cpu(entry->e_value_inum);
1174 err = ext4_xattr_inode_iget(parent, ea_ino,
1175 le32_to_cpu(entry->e_hash),
1176 &ea_inode);
1177 if (err)
1178 continue;
1179
1180 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1181 if (err) {
1182 ext4_warning_inode(ea_inode,
1183 "Expand inode array err=%d", err);
1184 iput(ea_inode);
1185 continue;
1186 }
1187
1188 err = ext4_xattr_ensure_credits(handle, parent, credits, bh,
1189 dirty, block_csum);
1190 if (err) {
1191 ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1192 err);
1193 continue;
1194 }
1195
1196 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1197 if (err) {
1198 ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1199 err);
1200 continue;
1201 }
1202
1203 if (!skip_quota)
1204 ext4_xattr_inode_free_quota(parent, ea_inode,
1205 le32_to_cpu(entry->e_value_size));
1206
1207 /*
1208 * Forget about ea_inode within the same transaction that
1209 * decrements the ref count. This avoids duplicate decrements in
1210 * case the rest of the work spills over to subsequent
1211 * transactions.
1212 */
1213 entry->e_value_inum = 0;
1214 entry->e_value_size = 0;
1215
1216 dirty = true;
1217 }
1218
1219 if (dirty) {
1220 /*
1221 * Note that we are deliberately skipping csum calculation for
1222 * the final update because we do not expect any journal
1223 * restarts until xattr block is freed.
1224 */
1225
1226 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1227 if (err)
1228 ext4_warning_inode(parent,
1229 "handle dirty metadata err=%d", err);
1230 }
1231}
1232
1233/*
1234 * Release the xattr block BH: If the reference count is > 1, decrement it;
1235 * otherwise free the block.
1236 */
1237static void
1238ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1239 struct buffer_head *bh,
1240 struct ext4_xattr_inode_array **ea_inode_array,
1241 int extra_credits)
1242{
1243 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1244 u32 hash, ref;
1245 int error = 0;
1246
1247 BUFFER_TRACE(bh, "get_write_access");
1248 error = ext4_journal_get_write_access(handle, bh);
1249 if (error)
1250 goto out;
1251
1252 lock_buffer(bh);
1253 hash = le32_to_cpu(BHDR(bh)->h_hash);
1254 ref = le32_to_cpu(BHDR(bh)->h_refcount);
1255 if (ref == 1) {
1256 ea_bdebug(bh, "refcount now=0; freeing");
1257 /*
1258 * This must happen under buffer lock for
1259 * ext4_xattr_block_set() to reliably detect freed block
1260 */
1261 if (ea_block_cache)
1262 mb_cache_entry_delete(ea_block_cache, hash,
1263 bh->b_blocknr);
1264 get_bh(bh);
1265 unlock_buffer(bh);
1266
1267 if (ext4_has_feature_ea_inode(inode->i_sb))
1268 ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1269 BFIRST(bh),
1270 true /* block_csum */,
1271 ea_inode_array,
1272 extra_credits,
1273 true /* skip_quota */);
1274 ext4_free_blocks(handle, inode, bh, 0, 1,
1275 EXT4_FREE_BLOCKS_METADATA |
1276 EXT4_FREE_BLOCKS_FORGET);
1277 } else {
1278 ref--;
1279 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1280 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1281 struct mb_cache_entry *ce;
1282
1283 if (ea_block_cache) {
1284 ce = mb_cache_entry_get(ea_block_cache, hash,
1285 bh->b_blocknr);
1286 if (ce) {
1287 ce->e_reusable = 1;
1288 mb_cache_entry_put(ea_block_cache, ce);
1289 }
1290 }
1291 }
1292
1293 ext4_xattr_block_csum_set(inode, bh);
1294 /*
1295 * Beware of this ugliness: Releasing of xattr block references
1296 * from different inodes can race and so we have to protect
1297 * from a race where someone else frees the block (and releases
1298 * its journal_head) before we are done dirtying the buffer. In
1299 * nojournal mode this race is harmless and we actually cannot
1300 * call ext4_handle_dirty_metadata() with locked buffer as
1301 * that function can call sync_dirty_buffer() so for that case
1302 * we handle the dirtying after unlocking the buffer.
1303 */
1304 if (ext4_handle_valid(handle))
1305 error = ext4_handle_dirty_metadata(handle, inode, bh);
1306 unlock_buffer(bh);
1307 if (!ext4_handle_valid(handle))
1308 error = ext4_handle_dirty_metadata(handle, inode, bh);
1309 if (IS_SYNC(inode))
1310 ext4_handle_sync(handle);
1311 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1312 ea_bdebug(bh, "refcount now=%d; releasing",
1313 le32_to_cpu(BHDR(bh)->h_refcount));
1314 }
1315out:
1316 ext4_std_error(inode->i_sb, error);
1317 return;
1318}
1319
1320/*
1321 * Find the available free space for EAs. This also returns the total number of
1322 * bytes used by EA entries.
1323 */
1324static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1325 size_t *min_offs, void *base, int *total)
1326{
1327 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1328 if (!last->e_value_inum && last->e_value_size) {
1329 size_t offs = le16_to_cpu(last->e_value_offs);
1330 if (offs < *min_offs)
1331 *min_offs = offs;
1332 }
1333 if (total)
1334 *total += EXT4_XATTR_LEN(last->e_name_len);
1335 }
1336 return (*min_offs - ((void *)last - base) - sizeof(__u32));
1337}
1338
1339/*
1340 * Write the value of the EA in an inode.
1341 */
1342static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1343 const void *buf, int bufsize)
1344{
1345 struct buffer_head *bh = NULL;
1346 unsigned long block = 0;
1347 int blocksize = ea_inode->i_sb->s_blocksize;
1348 int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1349 int csize, wsize = 0;
1350 int ret = 0;
1351 int retries = 0;
1352
1353retry:
1354 while (ret >= 0 && ret < max_blocks) {
1355 struct ext4_map_blocks map;
1356 map.m_lblk = block += ret;
1357 map.m_len = max_blocks -= ret;
1358
1359 ret = ext4_map_blocks(handle, ea_inode, &map,
1360 EXT4_GET_BLOCKS_CREATE);
1361 if (ret <= 0) {
1362 ext4_mark_inode_dirty(handle, ea_inode);
1363 if (ret == -ENOSPC &&
1364 ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1365 ret = 0;
1366 goto retry;
1367 }
1368 break;
1369 }
1370 }
1371
1372 if (ret < 0)
1373 return ret;
1374
1375 block = 0;
1376 while (wsize < bufsize) {
1377 if (bh != NULL)
1378 brelse(bh);
1379 csize = (bufsize - wsize) > blocksize ? blocksize :
1380 bufsize - wsize;
1381 bh = ext4_getblk(handle, ea_inode, block, 0);
1382 if (IS_ERR(bh))
1383 return PTR_ERR(bh);
1384 if (!bh) {
1385 WARN_ON_ONCE(1);
1386 EXT4_ERROR_INODE(ea_inode,
1387 "ext4_getblk() return bh = NULL");
1388 return -EFSCORRUPTED;
1389 }
1390 ret = ext4_journal_get_write_access(handle, bh);
1391 if (ret)
1392 goto out;
1393
1394 memcpy(bh->b_data, buf, csize);
1395 set_buffer_uptodate(bh);
1396 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1397
1398 buf += csize;
1399 wsize += csize;
1400 block += 1;
1401 }
1402
1403 inode_lock(ea_inode);
1404 i_size_write(ea_inode, wsize);
1405 ext4_update_i_disksize(ea_inode, wsize);
1406 inode_unlock(ea_inode);
1407
1408 ext4_mark_inode_dirty(handle, ea_inode);
1409
1410out:
1411 brelse(bh);
1412
1413 return ret;
1414}
1415
1416/*
1417 * Create an inode to store the value of a large EA.
1418 */
1419static struct inode *ext4_xattr_inode_create(handle_t *handle,
1420 struct inode *inode, u32 hash)
1421{
1422 struct inode *ea_inode = NULL;
1423 uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1424 int err;
1425
1426 /*
1427 * Let the next inode be the goal, so we try and allocate the EA inode
1428 * in the same group, or nearby one.
1429 */
1430 ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1431 S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1432 EXT4_EA_INODE_FL);
1433 if (!IS_ERR(ea_inode)) {
1434 ea_inode->i_op = &ext4_file_inode_operations;
1435 ea_inode->i_fop = &ext4_file_operations;
1436 ext4_set_aops(ea_inode);
1437 ext4_xattr_inode_set_class(ea_inode);
1438 unlock_new_inode(ea_inode);
1439 ext4_xattr_inode_set_ref(ea_inode, 1);
1440 ext4_xattr_inode_set_hash(ea_inode, hash);
1441 err = ext4_mark_inode_dirty(handle, ea_inode);
1442 if (!err)
1443 err = ext4_inode_attach_jinode(ea_inode);
1444 if (err) {
1445 iput(ea_inode);
1446 return ERR_PTR(err);
1447 }
1448
1449 /*
1450 * Xattr inodes are shared therefore quota charging is performed
1451 * at a higher level.
1452 */
1453 dquot_free_inode(ea_inode);
1454 dquot_drop(ea_inode);
1455 inode_lock(ea_inode);
1456 ea_inode->i_flags |= S_NOQUOTA;
1457 inode_unlock(ea_inode);
1458 }
1459
1460 return ea_inode;
1461}
1462
1463static struct inode *
1464ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1465 size_t value_len, u32 hash)
1466{
1467 struct inode *ea_inode;
1468 struct mb_cache_entry *ce;
1469 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1470 void *ea_data;
1471
1472 if (!ea_inode_cache)
1473 return NULL;
1474
1475 ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1476 if (!ce)
1477 return NULL;
1478
1479 ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
1480 if (!ea_data) {
1481 mb_cache_entry_put(ea_inode_cache, ce);
1482 return NULL;
1483 }
1484
1485 while (ce) {
1486 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1487 EXT4_IGET_NORMAL);
1488 if (!IS_ERR(ea_inode) &&
1489 !is_bad_inode(ea_inode) &&
1490 (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1491 i_size_read(ea_inode) == value_len &&
1492 !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1493 !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1494 value_len) &&
1495 !memcmp(value, ea_data, value_len)) {
1496 mb_cache_entry_touch(ea_inode_cache, ce);
1497 mb_cache_entry_put(ea_inode_cache, ce);
1498 kvfree(ea_data);
1499 return ea_inode;
1500 }
1501
1502 if (!IS_ERR(ea_inode))
1503 iput(ea_inode);
1504 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1505 }
1506 kvfree(ea_data);
1507 return NULL;
1508}
1509
1510/*
1511 * Add value of the EA in an inode.
1512 */
1513static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1514 const void *value, size_t value_len,
1515 struct inode **ret_inode)
1516{
1517 struct inode *ea_inode;
1518 u32 hash;
1519 int err;
1520
1521 hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1522 ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1523 if (ea_inode) {
1524 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1525 if (err) {
1526 iput(ea_inode);
1527 return err;
1528 }
1529
1530 *ret_inode = ea_inode;
1531 return 0;
1532 }
1533
1534 /* Create an inode for the EA value */
1535 ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1536 if (IS_ERR(ea_inode))
1537 return PTR_ERR(ea_inode);
1538
1539 err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1540 if (err) {
1541 ext4_xattr_inode_dec_ref(handle, ea_inode);
1542 iput(ea_inode);
1543 return err;
1544 }
1545
1546 if (EA_INODE_CACHE(inode))
1547 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1548 ea_inode->i_ino, true /* reusable */);
1549
1550 *ret_inode = ea_inode;
1551 return 0;
1552}
1553
1554/*
1555 * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1556 * feature is enabled.
1557 */
1558#define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1559
1560static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1561 struct ext4_xattr_search *s,
1562 handle_t *handle, struct inode *inode,
1563 bool is_block)
1564{
1565 struct ext4_xattr_entry *last, *next;
1566 struct ext4_xattr_entry *here = s->here;
1567 size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1568 int in_inode = i->in_inode;
1569 struct inode *old_ea_inode = NULL;
1570 struct inode *new_ea_inode = NULL;
1571 size_t old_size, new_size;
1572 int ret;
1573
1574 /* Space used by old and new values. */
1575 old_size = (!s->not_found && !here->e_value_inum) ?
1576 EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1577 new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1578
1579 /*
1580 * Optimization for the simple case when old and new values have the
1581 * same padded sizes. Not applicable if external inodes are involved.
1582 */
1583 if (new_size && new_size == old_size) {
1584 size_t offs = le16_to_cpu(here->e_value_offs);
1585 void *val = s->base + offs;
1586
1587 here->e_value_size = cpu_to_le32(i->value_len);
1588 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1589 memset(val, 0, new_size);
1590 } else {
1591 memcpy(val, i->value, i->value_len);
1592 /* Clear padding bytes. */
1593 memset(val + i->value_len, 0, new_size - i->value_len);
1594 }
1595 goto update_hash;
1596 }
1597
1598 /* Compute min_offs and last. */
1599 last = s->first;
1600 for (; !IS_LAST_ENTRY(last); last = next) {
1601 next = EXT4_XATTR_NEXT(last);
1602 if ((void *)next >= s->end) {
1603 EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1604 ret = -EFSCORRUPTED;
1605 goto out;
1606 }
1607 if (!last->e_value_inum && last->e_value_size) {
1608 size_t offs = le16_to_cpu(last->e_value_offs);
1609 if (offs < min_offs)
1610 min_offs = offs;
1611 }
1612 }
1613
1614 /* Check whether we have enough space. */
1615 if (i->value) {
1616 size_t free;
1617
1618 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1619 if (!s->not_found)
1620 free += EXT4_XATTR_LEN(name_len) + old_size;
1621
1622 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1623 ret = -ENOSPC;
1624 goto out;
1625 }
1626
1627 /*
1628 * If storing the value in an external inode is an option,
1629 * reserve space for xattr entries/names in the external
1630 * attribute block so that a long value does not occupy the
1631 * whole space and prevent futher entries being added.
1632 */
1633 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1634 new_size && is_block &&
1635 (min_offs + old_size - new_size) <
1636 EXT4_XATTR_BLOCK_RESERVE(inode)) {
1637 ret = -ENOSPC;
1638 goto out;
1639 }
1640 }
1641
1642 /*
1643 * Getting access to old and new ea inodes is subject to failures.
1644 * Finish that work before doing any modifications to the xattr data.
1645 */
1646 if (!s->not_found && here->e_value_inum) {
1647 ret = ext4_xattr_inode_iget(inode,
1648 le32_to_cpu(here->e_value_inum),
1649 le32_to_cpu(here->e_hash),
1650 &old_ea_inode);
1651 if (ret) {
1652 old_ea_inode = NULL;
1653 goto out;
1654 }
1655 }
1656 if (i->value && in_inode) {
1657 WARN_ON_ONCE(!i->value_len);
1658
1659 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1660 if (ret)
1661 goto out;
1662
1663 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1664 i->value_len,
1665 &new_ea_inode);
1666 if (ret) {
1667 new_ea_inode = NULL;
1668 ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1669 goto out;
1670 }
1671 }
1672
1673 if (old_ea_inode) {
1674 /* We are ready to release ref count on the old_ea_inode. */
1675 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1676 if (ret) {
1677 /* Release newly required ref count on new_ea_inode. */
1678 if (new_ea_inode) {
1679 int err;
1680
1681 err = ext4_xattr_inode_dec_ref(handle,
1682 new_ea_inode);
1683 if (err)
1684 ext4_warning_inode(new_ea_inode,
1685 "dec ref new_ea_inode err=%d",
1686 err);
1687 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1688 i->value_len);
1689 }
1690 goto out;
1691 }
1692
1693 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1694 le32_to_cpu(here->e_value_size));
1695 }
1696
1697 /* No failures allowed past this point. */
1698
1699 if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1700 /* Remove the old value. */
1701 void *first_val = s->base + min_offs;
1702 size_t offs = le16_to_cpu(here->e_value_offs);
1703 void *val = s->base + offs;
1704
1705 memmove(first_val + old_size, first_val, val - first_val);
1706 memset(first_val, 0, old_size);
1707 min_offs += old_size;
1708
1709 /* Adjust all value offsets. */
1710 last = s->first;
1711 while (!IS_LAST_ENTRY(last)) {
1712 size_t o = le16_to_cpu(last->e_value_offs);
1713
1714 if (!last->e_value_inum &&
1715 last->e_value_size && o < offs)
1716 last->e_value_offs = cpu_to_le16(o + old_size);
1717 last = EXT4_XATTR_NEXT(last);
1718 }
1719 }
1720
1721 if (!i->value) {
1722 /* Remove old name. */
1723 size_t size = EXT4_XATTR_LEN(name_len);
1724
1725 last = ENTRY((void *)last - size);
1726 memmove(here, (void *)here + size,
1727 (void *)last - (void *)here + sizeof(__u32));
1728 memset(last, 0, size);
1729 } else if (s->not_found) {
1730 /* Insert new name. */
1731 size_t size = EXT4_XATTR_LEN(name_len);
1732 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1733
1734 memmove((void *)here + size, here, rest);
1735 memset(here, 0, size);
1736 here->e_name_index = i->name_index;
1737 here->e_name_len = name_len;
1738 memcpy(here->e_name, i->name, name_len);
1739 } else {
1740 /* This is an update, reset value info. */
1741 here->e_value_inum = 0;
1742 here->e_value_offs = 0;
1743 here->e_value_size = 0;
1744 }
1745
1746 if (i->value) {
1747 /* Insert new value. */
1748 if (in_inode) {
1749 here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1750 } else if (i->value_len) {
1751 void *val = s->base + min_offs - new_size;
1752
1753 here->e_value_offs = cpu_to_le16(min_offs - new_size);
1754 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1755 memset(val, 0, new_size);
1756 } else {
1757 memcpy(val, i->value, i->value_len);
1758 /* Clear padding bytes. */
1759 memset(val + i->value_len, 0,
1760 new_size - i->value_len);
1761 }
1762 }
1763 here->e_value_size = cpu_to_le32(i->value_len);
1764 }
1765
1766update_hash:
1767 if (i->value) {
1768 __le32 hash = 0;
1769
1770 /* Entry hash calculation. */
1771 if (in_inode) {
1772 __le32 crc32c_hash;
1773
1774 /*
1775 * Feed crc32c hash instead of the raw value for entry
1776 * hash calculation. This is to avoid walking
1777 * potentially long value buffer again.
1778 */
1779 crc32c_hash = cpu_to_le32(
1780 ext4_xattr_inode_get_hash(new_ea_inode));
1781 hash = ext4_xattr_hash_entry(here->e_name,
1782 here->e_name_len,
1783 &crc32c_hash, 1);
1784 } else if (is_block) {
1785 __le32 *value = s->base + le16_to_cpu(
1786 here->e_value_offs);
1787
1788 hash = ext4_xattr_hash_entry(here->e_name,
1789 here->e_name_len, value,
1790 new_size >> 2);
1791 }
1792 here->e_hash = hash;
1793 }
1794
1795 if (is_block)
1796 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1797
1798 ret = 0;
1799out:
1800 iput(old_ea_inode);
1801 iput(new_ea_inode);
1802 return ret;
1803}
1804
1805struct ext4_xattr_block_find {
1806 struct ext4_xattr_search s;
1807 struct buffer_head *bh;
1808};
1809
1810static int
1811ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1812 struct ext4_xattr_block_find *bs)
1813{
1814 struct super_block *sb = inode->i_sb;
1815 int error;
1816
1817 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1818 i->name_index, i->name, i->value, (long)i->value_len);
1819
1820 if (EXT4_I(inode)->i_file_acl) {
1821 /* The inode already has an extended attribute block. */
1822 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1823 if (IS_ERR(bs->bh))
1824 return PTR_ERR(bs->bh);
1825 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1826 atomic_read(&(bs->bh->b_count)),
1827 le32_to_cpu(BHDR(bs->bh)->h_refcount));
1828 error = ext4_xattr_check_block(inode, bs->bh);
1829 if (error)
1830 return error;
1831 /* Find the named attribute. */
1832 bs->s.base = BHDR(bs->bh);
1833 bs->s.first = BFIRST(bs->bh);
1834 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1835 bs->s.here = bs->s.first;
1836 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1837 i->name_index, i->name, 1);
1838 if (error && error != -ENODATA)
1839 return error;
1840 bs->s.not_found = error;
1841 }
1842 return 0;
1843}
1844
1845static int
1846ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1847 struct ext4_xattr_info *i,
1848 struct ext4_xattr_block_find *bs)
1849{
1850 struct super_block *sb = inode->i_sb;
1851 struct buffer_head *new_bh = NULL;
1852 struct ext4_xattr_search s_copy = bs->s;
1853 struct ext4_xattr_search *s = &s_copy;
1854 struct mb_cache_entry *ce = NULL;
1855 int error = 0;
1856 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1857 struct inode *ea_inode = NULL, *tmp_inode;
1858 size_t old_ea_inode_quota = 0;
1859 unsigned int ea_ino;
1860
1861
1862#define header(x) ((struct ext4_xattr_header *)(x))
1863
1864 if (s->base) {
1865 BUFFER_TRACE(bs->bh, "get_write_access");
1866 error = ext4_journal_get_write_access(handle, bs->bh);
1867 if (error)
1868 goto cleanup;
1869 lock_buffer(bs->bh);
1870
1871 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1872 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1873
1874 /*
1875 * This must happen under buffer lock for
1876 * ext4_xattr_block_set() to reliably detect modified
1877 * block
1878 */
1879 if (ea_block_cache)
1880 mb_cache_entry_delete(ea_block_cache, hash,
1881 bs->bh->b_blocknr);
1882 ea_bdebug(bs->bh, "modifying in-place");
1883 error = ext4_xattr_set_entry(i, s, handle, inode,
1884 true /* is_block */);
1885 ext4_xattr_block_csum_set(inode, bs->bh);
1886 unlock_buffer(bs->bh);
1887 if (error == -EFSCORRUPTED)
1888 goto bad_block;
1889 if (!error)
1890 error = ext4_handle_dirty_metadata(handle,
1891 inode,
1892 bs->bh);
1893 if (error)
1894 goto cleanup;
1895 goto inserted;
1896 } else {
1897 int offset = (char *)s->here - bs->bh->b_data;
1898
1899 unlock_buffer(bs->bh);
1900 ea_bdebug(bs->bh, "cloning");
1901 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1902 error = -ENOMEM;
1903 if (s->base == NULL)
1904 goto cleanup;
1905 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1906 s->first = ENTRY(header(s->base)+1);
1907 header(s->base)->h_refcount = cpu_to_le32(1);
1908 s->here = ENTRY(s->base + offset);
1909 s->end = s->base + bs->bh->b_size;
1910
1911 /*
1912 * If existing entry points to an xattr inode, we need
1913 * to prevent ext4_xattr_set_entry() from decrementing
1914 * ref count on it because the reference belongs to the
1915 * original block. In this case, make the entry look
1916 * like it has an empty value.
1917 */
1918 if (!s->not_found && s->here->e_value_inum) {
1919 ea_ino = le32_to_cpu(s->here->e_value_inum);
1920 error = ext4_xattr_inode_iget(inode, ea_ino,
1921 le32_to_cpu(s->here->e_hash),
1922 &tmp_inode);
1923 if (error)
1924 goto cleanup;
1925
1926 if (!ext4_test_inode_state(tmp_inode,
1927 EXT4_STATE_LUSTRE_EA_INODE)) {
1928 /*
1929 * Defer quota free call for previous
1930 * inode until success is guaranteed.
1931 */
1932 old_ea_inode_quota = le32_to_cpu(
1933 s->here->e_value_size);
1934 }
1935 iput(tmp_inode);
1936
1937 s->here->e_value_inum = 0;
1938 s->here->e_value_size = 0;
1939 }
1940 }
1941 } else {
1942 /* Allocate a buffer where we construct the new block. */
1943 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1944 /* assert(header == s->base) */
1945 error = -ENOMEM;
1946 if (s->base == NULL)
1947 goto cleanup;
1948 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1949 header(s->base)->h_blocks = cpu_to_le32(1);
1950 header(s->base)->h_refcount = cpu_to_le32(1);
1951 s->first = ENTRY(header(s->base)+1);
1952 s->here = ENTRY(header(s->base)+1);
1953 s->end = s->base + sb->s_blocksize;
1954 }
1955
1956 error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1957 if (error == -EFSCORRUPTED)
1958 goto bad_block;
1959 if (error)
1960 goto cleanup;
1961
1962 if (i->value && s->here->e_value_inum) {
1963 /*
1964 * A ref count on ea_inode has been taken as part of the call to
1965 * ext4_xattr_set_entry() above. We would like to drop this
1966 * extra ref but we have to wait until the xattr block is
1967 * initialized and has its own ref count on the ea_inode.
1968 */
1969 ea_ino = le32_to_cpu(s->here->e_value_inum);
1970 error = ext4_xattr_inode_iget(inode, ea_ino,
1971 le32_to_cpu(s->here->e_hash),
1972 &ea_inode);
1973 if (error) {
1974 ea_inode = NULL;
1975 goto cleanup;
1976 }
1977 }
1978
1979inserted:
1980 if (!IS_LAST_ENTRY(s->first)) {
1981 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1982 &ce);
1983 if (new_bh) {
1984 /* We found an identical block in the cache. */
1985 if (new_bh == bs->bh)
1986 ea_bdebug(new_bh, "keeping");
1987 else {
1988 u32 ref;
1989
1990 WARN_ON_ONCE(dquot_initialize_needed(inode));
1991
1992 /* The old block is released after updating
1993 the inode. */
1994 error = dquot_alloc_block(inode,
1995 EXT4_C2B(EXT4_SB(sb), 1));
1996 if (error)
1997 goto cleanup;
1998 BUFFER_TRACE(new_bh, "get_write_access");
1999 error = ext4_journal_get_write_access(handle,
2000 new_bh);
2001 if (error)
2002 goto cleanup_dquot;
2003 lock_buffer(new_bh);
2004 /*
2005 * We have to be careful about races with
2006 * freeing, rehashing or adding references to
2007 * xattr block. Once we hold buffer lock xattr
2008 * block's state is stable so we can check
2009 * whether the block got freed / rehashed or
2010 * not. Since we unhash mbcache entry under
2011 * buffer lock when freeing / rehashing xattr
2012 * block, checking whether entry is still
2013 * hashed is reliable. Same rules hold for
2014 * e_reusable handling.
2015 */
2016 if (hlist_bl_unhashed(&ce->e_hash_list) ||
2017 !ce->e_reusable) {
2018 /*
2019 * Undo everything and check mbcache
2020 * again.
2021 */
2022 unlock_buffer(new_bh);
2023 dquot_free_block(inode,
2024 EXT4_C2B(EXT4_SB(sb),
2025 1));
2026 brelse(new_bh);
2027 mb_cache_entry_put(ea_block_cache, ce);
2028 ce = NULL;
2029 new_bh = NULL;
2030 goto inserted;
2031 }
2032 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2033 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2034 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2035 ce->e_reusable = 0;
2036 ea_bdebug(new_bh, "reusing; refcount now=%d",
2037 ref);
2038 ext4_xattr_block_csum_set(inode, new_bh);
2039 unlock_buffer(new_bh);
2040 error = ext4_handle_dirty_metadata(handle,
2041 inode,
2042 new_bh);
2043 if (error)
2044 goto cleanup_dquot;
2045 }
2046 mb_cache_entry_touch(ea_block_cache, ce);
2047 mb_cache_entry_put(ea_block_cache, ce);
2048 ce = NULL;
2049 } else if (bs->bh && s->base == bs->bh->b_data) {
2050 /* We were modifying this block in-place. */
2051 ea_bdebug(bs->bh, "keeping this block");
2052 ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2053 new_bh = bs->bh;
2054 get_bh(new_bh);
2055 } else {
2056 /* We need to allocate a new block */
2057 ext4_fsblk_t goal, block;
2058
2059 WARN_ON_ONCE(dquot_initialize_needed(inode));
2060
2061 goal = ext4_group_first_block_no(sb,
2062 EXT4_I(inode)->i_block_group);
2063
2064 /* non-extent files can't have physical blocks past 2^32 */
2065 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2066 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2067
2068 block = ext4_new_meta_blocks(handle, inode, goal, 0,
2069 NULL, &error);
2070 if (error)
2071 goto cleanup;
2072
2073 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2074 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2075
2076 ea_idebug(inode, "creating block %llu",
2077 (unsigned long long)block);
2078
2079 new_bh = sb_getblk(sb, block);
2080 if (unlikely(!new_bh)) {
2081 error = -ENOMEM;
2082getblk_failed:
2083 ext4_free_blocks(handle, inode, NULL, block, 1,
2084 EXT4_FREE_BLOCKS_METADATA);
2085 goto cleanup;
2086 }
2087 error = ext4_xattr_inode_inc_ref_all(handle, inode,
2088 ENTRY(header(s->base)+1));
2089 if (error)
2090 goto getblk_failed;
2091 if (ea_inode) {
2092 /* Drop the extra ref on ea_inode. */
2093 error = ext4_xattr_inode_dec_ref(handle,
2094 ea_inode);
2095 if (error)
2096 ext4_warning_inode(ea_inode,
2097 "dec ref error=%d",
2098 error);
2099 iput(ea_inode);
2100 ea_inode = NULL;
2101 }
2102
2103 lock_buffer(new_bh);
2104 error = ext4_journal_get_create_access(handle, new_bh);
2105 if (error) {
2106 unlock_buffer(new_bh);
2107 error = -EIO;
2108 goto getblk_failed;
2109 }
2110 memcpy(new_bh->b_data, s->base, new_bh->b_size);
2111 ext4_xattr_block_csum_set(inode, new_bh);
2112 set_buffer_uptodate(new_bh);
2113 unlock_buffer(new_bh);
2114 ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2115 error = ext4_handle_dirty_metadata(handle, inode,
2116 new_bh);
2117 if (error)
2118 goto cleanup;
2119 }
2120 }
2121
2122 if (old_ea_inode_quota)
2123 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2124
2125 /* Update the inode. */
2126 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2127
2128 /* Drop the previous xattr block. */
2129 if (bs->bh && bs->bh != new_bh) {
2130 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2131
2132 ext4_xattr_release_block(handle, inode, bs->bh,
2133 &ea_inode_array,
2134 0 /* extra_credits */);
2135 ext4_xattr_inode_array_free(ea_inode_array);
2136 }
2137 error = 0;
2138
2139cleanup:
2140 if (ea_inode) {
2141 int error2;
2142
2143 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2144 if (error2)
2145 ext4_warning_inode(ea_inode, "dec ref error=%d",
2146 error2);
2147
2148 /* If there was an error, revert the quota charge. */
2149 if (error)
2150 ext4_xattr_inode_free_quota(inode, ea_inode,
2151 i_size_read(ea_inode));
2152 iput(ea_inode);
2153 }
2154 if (ce)
2155 mb_cache_entry_put(ea_block_cache, ce);
2156 brelse(new_bh);
2157 if (!(bs->bh && s->base == bs->bh->b_data))
2158 kfree(s->base);
2159
2160 return error;
2161
2162cleanup_dquot:
2163 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2164 goto cleanup;
2165
2166bad_block:
2167 EXT4_ERROR_INODE(inode, "bad block %llu",
2168 EXT4_I(inode)->i_file_acl);
2169 goto cleanup;
2170
2171#undef header
2172}
2173
2174int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2175 struct ext4_xattr_ibody_find *is)
2176{
2177 struct ext4_xattr_ibody_header *header;
2178 struct ext4_inode *raw_inode;
2179 int error;
2180
2181 if (EXT4_I(inode)->i_extra_isize == 0)
2182 return 0;
2183 raw_inode = ext4_raw_inode(&is->iloc);
2184 header = IHDR(inode, raw_inode);
2185 is->s.base = is->s.first = IFIRST(header);
2186 is->s.here = is->s.first;
2187 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2188 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2189 error = xattr_check_inode(inode, header, is->s.end);
2190 if (error)
2191 return error;
2192 /* Find the named attribute. */
2193 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2194 i->name_index, i->name, 0);
2195 if (error && error != -ENODATA)
2196 return error;
2197 is->s.not_found = error;
2198 }
2199 return 0;
2200}
2201
2202int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
2203 struct ext4_xattr_info *i,
2204 struct ext4_xattr_ibody_find *is)
2205{
2206 struct ext4_xattr_ibody_header *header;
2207 struct ext4_xattr_search *s = &is->s;
2208 int error;
2209
2210 if (EXT4_I(inode)->i_extra_isize == 0)
2211 return -ENOSPC;
2212 error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2213 if (error)
2214 return error;
2215 header = IHDR(inode, ext4_raw_inode(&is->iloc));
2216 if (!IS_LAST_ENTRY(s->first)) {
2217 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2218 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2219 } else {
2220 header->h_magic = cpu_to_le32(0);
2221 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2222 }
2223 return 0;
2224}
2225
2226static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2227 struct ext4_xattr_info *i,
2228 struct ext4_xattr_ibody_find *is)
2229{
2230 struct ext4_xattr_ibody_header *header;
2231 struct ext4_xattr_search *s = &is->s;
2232 int error;
2233
2234 if (EXT4_I(inode)->i_extra_isize == 0)
2235 return -ENOSPC;
2236 error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2237 if (error)
2238 return error;
2239 header = IHDR(inode, ext4_raw_inode(&is->iloc));
2240 if (!IS_LAST_ENTRY(s->first)) {
2241 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2242 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2243 } else {
2244 header->h_magic = cpu_to_le32(0);
2245 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2246 }
2247 return 0;
2248}
2249
2250static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2251 struct ext4_xattr_info *i)
2252{
2253 void *value;
2254
2255 /* When e_value_inum is set the value is stored externally. */
2256 if (s->here->e_value_inum)
2257 return 0;
2258 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2259 return 0;
2260 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2261 return !memcmp(value, i->value, i->value_len);
2262}
2263
2264static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2265{
2266 struct buffer_head *bh;
2267 int error;
2268
2269 if (!EXT4_I(inode)->i_file_acl)
2270 return NULL;
2271 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2272 if (IS_ERR(bh))
2273 return bh;
2274 error = ext4_xattr_check_block(inode, bh);
2275 if (error) {
2276 brelse(bh);
2277 return ERR_PTR(error);
2278 }
2279 return bh;
2280}
2281
2282/*
2283 * ext4_xattr_set_handle()
2284 *
2285 * Create, replace or remove an extended attribute for this inode. Value
2286 * is NULL to remove an existing extended attribute, and non-NULL to
2287 * either replace an existing extended attribute, or create a new extended
2288 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2289 * specify that an extended attribute must exist and must not exist
2290 * previous to the call, respectively.
2291 *
2292 * Returns 0, or a negative error number on failure.
2293 */
2294int
2295ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2296 const char *name, const void *value, size_t value_len,
2297 int flags)
2298{
2299 struct ext4_xattr_info i = {
2300 .name_index = name_index,
2301 .name = name,
2302 .value = value,
2303 .value_len = value_len,
2304 .in_inode = 0,
2305 };
2306 struct ext4_xattr_ibody_find is = {
2307 .s = { .not_found = -ENODATA, },
2308 };
2309 struct ext4_xattr_block_find bs = {
2310 .s = { .not_found = -ENODATA, },
2311 };
2312 int no_expand;
2313 int error;
2314
2315 if (!name)
2316 return -EINVAL;
2317 if (strlen(name) > 255)
2318 return -ERANGE;
2319
2320 ext4_write_lock_xattr(inode, &no_expand);
2321
2322 /* Check journal credits under write lock. */
2323 if (ext4_handle_valid(handle)) {
2324 struct buffer_head *bh;
2325 int credits;
2326
2327 bh = ext4_xattr_get_block(inode);
2328 if (IS_ERR(bh)) {
2329 error = PTR_ERR(bh);
2330 goto cleanup;
2331 }
2332
2333 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2334 value_len,
2335 flags & XATTR_CREATE);
2336 brelse(bh);
2337
2338 if (!ext4_handle_has_enough_credits(handle, credits)) {
2339 error = -ENOSPC;
2340 goto cleanup;
2341 }
2342 }
2343
2344 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2345 if (error)
2346 goto cleanup;
2347
2348 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2349 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2350 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2351 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2352 }
2353
2354 error = ext4_xattr_ibody_find(inode, &i, &is);
2355 if (error)
2356 goto cleanup;
2357 if (is.s.not_found)
2358 error = ext4_xattr_block_find(inode, &i, &bs);
2359 if (error)
2360 goto cleanup;
2361 if (is.s.not_found && bs.s.not_found) {
2362 error = -ENODATA;
2363 if (flags & XATTR_REPLACE)
2364 goto cleanup;
2365 error = 0;
2366 if (!value)
2367 goto cleanup;
2368 } else {
2369 error = -EEXIST;
2370 if (flags & XATTR_CREATE)
2371 goto cleanup;
2372 }
2373
2374 if (!value) {
2375 if (!is.s.not_found)
2376 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2377 else if (!bs.s.not_found)
2378 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2379 } else {
2380 error = 0;
2381 /* Xattr value did not change? Save us some work and bail out */
2382 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2383 goto cleanup;
2384 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2385 goto cleanup;
2386
2387 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2388 (EXT4_XATTR_SIZE(i.value_len) >
2389 EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2390 i.in_inode = 1;
2391retry_inode:
2392 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2393 if (!error && !bs.s.not_found) {
2394 i.value = NULL;
2395 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2396 } else if (error == -ENOSPC) {
2397 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2398 brelse(bs.bh);
2399 bs.bh = NULL;
2400 error = ext4_xattr_block_find(inode, &i, &bs);
2401 if (error)
2402 goto cleanup;
2403 }
2404 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2405 if (!error && !is.s.not_found) {
2406 i.value = NULL;
2407 error = ext4_xattr_ibody_set(handle, inode, &i,
2408 &is);
2409 } else if (error == -ENOSPC) {
2410 /*
2411 * Xattr does not fit in the block, store at
2412 * external inode if possible.
2413 */
2414 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2415 !i.in_inode) {
2416 i.in_inode = 1;
2417 goto retry_inode;
2418 }
2419 }
2420 }
2421 }
2422 if (!error) {
2423 ext4_xattr_update_super_block(handle, inode->i_sb);
2424 inode->i_ctime = current_time(inode);
2425 if (!value)
2426 no_expand = 0;
2427 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2428 /*
2429 * The bh is consumed by ext4_mark_iloc_dirty, even with
2430 * error != 0.
2431 */
2432 is.iloc.bh = NULL;
2433 if (IS_SYNC(inode))
2434 ext4_handle_sync(handle);
2435 }
2436
2437cleanup:
2438 brelse(is.iloc.bh);
2439 brelse(bs.bh);
2440 ext4_write_unlock_xattr(inode, &no_expand);
2441 return error;
2442}
2443
2444int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2445 bool is_create, int *credits)
2446{
2447 struct buffer_head *bh;
2448 int err;
2449
2450 *credits = 0;
2451
2452 if (!EXT4_SB(inode->i_sb)->s_journal)
2453 return 0;
2454
2455 down_read(&EXT4_I(inode)->xattr_sem);
2456
2457 bh = ext4_xattr_get_block(inode);
2458 if (IS_ERR(bh)) {
2459 err = PTR_ERR(bh);
2460 } else {
2461 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2462 value_len, is_create);
2463 brelse(bh);
2464 err = 0;
2465 }
2466
2467 up_read(&EXT4_I(inode)->xattr_sem);
2468 return err;
2469}
2470
2471/*
2472 * ext4_xattr_set()
2473 *
2474 * Like ext4_xattr_set_handle, but start from an inode. This extended
2475 * attribute modification is a filesystem transaction by itself.
2476 *
2477 * Returns 0, or a negative error number on failure.
2478 */
2479int
2480ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2481 const void *value, size_t value_len, int flags)
2482{
2483 handle_t *handle;
2484 struct super_block *sb = inode->i_sb;
2485 int error, retries = 0;
2486 int credits;
2487
2488 error = dquot_initialize(inode);
2489 if (error)
2490 return error;
2491
2492retry:
2493 error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2494 &credits);
2495 if (error)
2496 return error;
2497
2498 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2499 if (IS_ERR(handle)) {
2500 error = PTR_ERR(handle);
2501 } else {
2502 int error2;
2503
2504 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2505 value, value_len, flags);
2506 error2 = ext4_journal_stop(handle);
2507 if (error == -ENOSPC &&
2508 ext4_should_retry_alloc(sb, &retries))
2509 goto retry;
2510 if (error == 0)
2511 error = error2;
2512 }
2513
2514 return error;
2515}
2516
2517/*
2518 * Shift the EA entries in the inode to create space for the increased
2519 * i_extra_isize.
2520 */
2521static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2522 int value_offs_shift, void *to,
2523 void *from, size_t n)
2524{
2525 struct ext4_xattr_entry *last = entry;
2526 int new_offs;
2527
2528 /* We always shift xattr headers further thus offsets get lower */
2529 BUG_ON(value_offs_shift > 0);
2530
2531 /* Adjust the value offsets of the entries */
2532 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2533 if (!last->e_value_inum && last->e_value_size) {
2534 new_offs = le16_to_cpu(last->e_value_offs) +
2535 value_offs_shift;
2536 last->e_value_offs = cpu_to_le16(new_offs);
2537 }
2538 }
2539 /* Shift the entries by n bytes */
2540 memmove(to, from, n);
2541}
2542
2543/*
2544 * Move xattr pointed to by 'entry' from inode into external xattr block
2545 */
2546static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2547 struct ext4_inode *raw_inode,
2548 struct ext4_xattr_entry *entry)
2549{
2550 struct ext4_xattr_ibody_find *is = NULL;
2551 struct ext4_xattr_block_find *bs = NULL;
2552 char *buffer = NULL, *b_entry_name = NULL;
2553 size_t value_size = le32_to_cpu(entry->e_value_size);
2554 struct ext4_xattr_info i = {
2555 .value = NULL,
2556 .value_len = 0,
2557 .name_index = entry->e_name_index,
2558 .in_inode = !!entry->e_value_inum,
2559 };
2560 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2561 int error;
2562
2563 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2564 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2565 buffer = kmalloc(value_size, GFP_NOFS);
2566 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2567 if (!is || !bs || !buffer || !b_entry_name) {
2568 error = -ENOMEM;
2569 goto out;
2570 }
2571
2572 is->s.not_found = -ENODATA;
2573 bs->s.not_found = -ENODATA;
2574 is->iloc.bh = NULL;
2575 bs->bh = NULL;
2576
2577 /* Save the entry name and the entry value */
2578 if (entry->e_value_inum) {
2579 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2580 if (error)
2581 goto out;
2582 } else {
2583 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2584 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2585 }
2586
2587 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2588 b_entry_name[entry->e_name_len] = '\0';
2589 i.name = b_entry_name;
2590
2591 error = ext4_get_inode_loc(inode, &is->iloc);
2592 if (error)
2593 goto out;
2594
2595 error = ext4_xattr_ibody_find(inode, &i, is);
2596 if (error)
2597 goto out;
2598
2599 /* Remove the chosen entry from the inode */
2600 error = ext4_xattr_ibody_set(handle, inode, &i, is);
2601 if (error)
2602 goto out;
2603
2604 i.value = buffer;
2605 i.value_len = value_size;
2606 error = ext4_xattr_block_find(inode, &i, bs);
2607 if (error)
2608 goto out;
2609
2610 /* Add entry which was removed from the inode into the block */
2611 error = ext4_xattr_block_set(handle, inode, &i, bs);
2612 if (error)
2613 goto out;
2614 error = 0;
2615out:
2616 kfree(b_entry_name);
2617 kfree(buffer);
2618 if (is)
2619 brelse(is->iloc.bh);
2620 if (bs)
2621 brelse(bs->bh);
2622 kfree(is);
2623 kfree(bs);
2624
2625 return error;
2626}
2627
2628static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2629 struct ext4_inode *raw_inode,
2630 int isize_diff, size_t ifree,
2631 size_t bfree, int *total_ino)
2632{
2633 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2634 struct ext4_xattr_entry *small_entry;
2635 struct ext4_xattr_entry *entry;
2636 struct ext4_xattr_entry *last;
2637 unsigned int entry_size; /* EA entry size */
2638 unsigned int total_size; /* EA entry size + value size */
2639 unsigned int min_total_size;
2640 int error;
2641
2642 while (isize_diff > ifree) {
2643 entry = NULL;
2644 small_entry = NULL;
2645 min_total_size = ~0U;
2646 last = IFIRST(header);
2647 /* Find the entry best suited to be pushed into EA block */
2648 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2649 /* never move system.data out of the inode */
2650 if ((last->e_name_len == 4) &&
2651 (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2652 !memcmp(last->e_name, "data", 4))
2653 continue;
2654 total_size = EXT4_XATTR_LEN(last->e_name_len);
2655 if (!last->e_value_inum)
2656 total_size += EXT4_XATTR_SIZE(
2657 le32_to_cpu(last->e_value_size));
2658 if (total_size <= bfree &&
2659 total_size < min_total_size) {
2660 if (total_size + ifree < isize_diff) {
2661 small_entry = last;
2662 } else {
2663 entry = last;
2664 min_total_size = total_size;
2665 }
2666 }
2667 }
2668
2669 if (entry == NULL) {
2670 if (small_entry == NULL)
2671 return -ENOSPC;
2672 entry = small_entry;
2673 }
2674
2675 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2676 total_size = entry_size;
2677 if (!entry->e_value_inum)
2678 total_size += EXT4_XATTR_SIZE(
2679 le32_to_cpu(entry->e_value_size));
2680 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2681 entry);
2682 if (error)
2683 return error;
2684
2685 *total_ino -= entry_size;
2686 ifree += total_size;
2687 bfree -= total_size;
2688 }
2689
2690 return 0;
2691}
2692
2693/*
2694 * Expand an inode by new_extra_isize bytes when EAs are present.
2695 * Returns 0 on success or negative error number on failure.
2696 */
2697int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2698 struct ext4_inode *raw_inode, handle_t *handle)
2699{
2700 struct ext4_xattr_ibody_header *header;
2701 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2702 static unsigned int mnt_count;
2703 size_t min_offs;
2704 size_t ifree, bfree;
2705 int total_ino;
2706 void *base, *end;
2707 int error = 0, tried_min_extra_isize = 0;
2708 int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2709 int isize_diff; /* How much do we need to grow i_extra_isize */
2710
2711retry:
2712 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2713 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2714 return 0;
2715
2716 header = IHDR(inode, raw_inode);
2717
2718 /*
2719 * Check if enough free space is available in the inode to shift the
2720 * entries ahead by new_extra_isize.
2721 */
2722
2723 base = IFIRST(header);
2724 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2725 min_offs = end - base;
2726 total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2727
2728 error = xattr_check_inode(inode, header, end);
2729 if (error)
2730 goto cleanup;
2731
2732 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2733 if (ifree >= isize_diff)
2734 goto shift;
2735
2736 /*
2737 * Enough free space isn't available in the inode, check if
2738 * EA block can hold new_extra_isize bytes.
2739 */
2740 if (EXT4_I(inode)->i_file_acl) {
2741 struct buffer_head *bh;
2742
2743 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2744 if (IS_ERR(bh)) {
2745 error = PTR_ERR(bh);
2746 goto cleanup;
2747 }
2748 error = ext4_xattr_check_block(inode, bh);
2749 if (error) {
2750 brelse(bh);
2751 goto cleanup;
2752 }
2753 base = BHDR(bh);
2754 end = bh->b_data + bh->b_size;
2755 min_offs = end - base;
2756 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2757 NULL);
2758 brelse(bh);
2759 if (bfree + ifree < isize_diff) {
2760 if (!tried_min_extra_isize && s_min_extra_isize) {
2761 tried_min_extra_isize++;
2762 new_extra_isize = s_min_extra_isize;
2763 goto retry;
2764 }
2765 error = -ENOSPC;
2766 goto cleanup;
2767 }
2768 } else {
2769 bfree = inode->i_sb->s_blocksize;
2770 }
2771
2772 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2773 isize_diff, ifree, bfree,
2774 &total_ino);
2775 if (error) {
2776 if (error == -ENOSPC && !tried_min_extra_isize &&
2777 s_min_extra_isize) {
2778 tried_min_extra_isize++;
2779 new_extra_isize = s_min_extra_isize;
2780 goto retry;
2781 }
2782 goto cleanup;
2783 }
2784shift:
2785 /* Adjust the offsets and shift the remaining entries ahead */
2786 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2787 - new_extra_isize, (void *)raw_inode +
2788 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2789 (void *)header, total_ino);
2790 EXT4_I(inode)->i_extra_isize = new_extra_isize;
2791
2792cleanup:
2793 if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2794 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2795 inode->i_ino);
2796 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2797 }
2798 return error;
2799}
2800
2801#define EIA_INCR 16 /* must be 2^n */
2802#define EIA_MASK (EIA_INCR - 1)
2803
2804/* Add the large xattr @inode into @ea_inode_array for deferred iput().
2805 * If @ea_inode_array is new or full it will be grown and the old
2806 * contents copied over.
2807 */
2808static int
2809ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2810 struct inode *inode)
2811{
2812 if (*ea_inode_array == NULL) {
2813 /*
2814 * Start with 15 inodes, so it fits into a power-of-two size.
2815 * If *ea_inode_array is NULL, this is essentially offsetof()
2816 */
2817 (*ea_inode_array) =
2818 kmalloc(offsetof(struct ext4_xattr_inode_array,
2819 inodes[EIA_MASK]),
2820 GFP_NOFS);
2821 if (*ea_inode_array == NULL)
2822 return -ENOMEM;
2823 (*ea_inode_array)->count = 0;
2824 } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2825 /* expand the array once all 15 + n * 16 slots are full */
2826 struct ext4_xattr_inode_array *new_array = NULL;
2827 int count = (*ea_inode_array)->count;
2828
2829 /* if new_array is NULL, this is essentially offsetof() */
2830 new_array = kmalloc(
2831 offsetof(struct ext4_xattr_inode_array,
2832 inodes[count + EIA_INCR]),
2833 GFP_NOFS);
2834 if (new_array == NULL)
2835 return -ENOMEM;
2836 memcpy(new_array, *ea_inode_array,
2837 offsetof(struct ext4_xattr_inode_array, inodes[count]));
2838 kfree(*ea_inode_array);
2839 *ea_inode_array = new_array;
2840 }
2841 (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2842 return 0;
2843}
2844
2845/*
2846 * ext4_xattr_delete_inode()
2847 *
2848 * Free extended attribute resources associated with this inode. Traverse
2849 * all entries and decrement reference on any xattr inodes associated with this
2850 * inode. This is called immediately before an inode is freed. We have exclusive
2851 * access to the inode. If an orphan inode is deleted it will also release its
2852 * references on xattr block and xattr inodes.
2853 */
2854int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2855 struct ext4_xattr_inode_array **ea_inode_array,
2856 int extra_credits)
2857{
2858 struct buffer_head *bh = NULL;
2859 struct ext4_xattr_ibody_header *header;
2860 struct ext4_iloc iloc = { .bh = NULL };
2861 struct ext4_xattr_entry *entry;
2862 struct inode *ea_inode;
2863 int error;
2864
2865 error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
2866 NULL /* bh */,
2867 false /* dirty */,
2868 false /* block_csum */);
2869 if (error) {
2870 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2871 goto cleanup;
2872 }
2873
2874 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2875 ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2876
2877 error = ext4_get_inode_loc(inode, &iloc);
2878 if (error) {
2879 EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2880 goto cleanup;
2881 }
2882
2883 error = ext4_journal_get_write_access(handle, iloc.bh);
2884 if (error) {
2885 EXT4_ERROR_INODE(inode, "write access (error %d)",
2886 error);
2887 goto cleanup;
2888 }
2889
2890 header = IHDR(inode, ext4_raw_inode(&iloc));
2891 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2892 ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2893 IFIRST(header),
2894 false /* block_csum */,
2895 ea_inode_array,
2896 extra_credits,
2897 false /* skip_quota */);
2898 }
2899
2900 if (EXT4_I(inode)->i_file_acl) {
2901 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2902 if (IS_ERR(bh)) {
2903 error = PTR_ERR(bh);
2904 if (error == -EIO)
2905 EXT4_ERROR_INODE(inode, "block %llu read error",
2906 EXT4_I(inode)->i_file_acl);
2907 bh = NULL;
2908 goto cleanup;
2909 }
2910 error = ext4_xattr_check_block(inode, bh);
2911 if (error)
2912 goto cleanup;
2913
2914 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2915 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2916 entry = EXT4_XATTR_NEXT(entry)) {
2917 if (!entry->e_value_inum)
2918 continue;
2919 error = ext4_xattr_inode_iget(inode,
2920 le32_to_cpu(entry->e_value_inum),
2921 le32_to_cpu(entry->e_hash),
2922 &ea_inode);
2923 if (error)
2924 continue;
2925 ext4_xattr_inode_free_quota(inode, ea_inode,
2926 le32_to_cpu(entry->e_value_size));
2927 iput(ea_inode);
2928 }
2929
2930 }
2931
2932 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2933 extra_credits);
2934 /*
2935 * Update i_file_acl value in the same transaction that releases
2936 * block.
2937 */
2938 EXT4_I(inode)->i_file_acl = 0;
2939 error = ext4_mark_inode_dirty(handle, inode);
2940 if (error) {
2941 EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2942 error);
2943 goto cleanup;
2944 }
2945 }
2946 error = 0;
2947cleanup:
2948 brelse(iloc.bh);
2949 brelse(bh);
2950 return error;
2951}
2952
2953void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2954{
2955 int idx;
2956
2957 if (ea_inode_array == NULL)
2958 return;
2959
2960 for (idx = 0; idx < ea_inode_array->count; ++idx)
2961 iput(ea_inode_array->inodes[idx]);
2962 kfree(ea_inode_array);
2963}
2964
2965/*
2966 * ext4_xattr_block_cache_insert()
2967 *
2968 * Create a new entry in the extended attribute block cache, and insert
2969 * it unless such an entry is already in the cache.
2970 *
2971 * Returns 0, or a negative error number on failure.
2972 */
2973static void
2974ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2975 struct buffer_head *bh)
2976{
2977 struct ext4_xattr_header *header = BHDR(bh);
2978 __u32 hash = le32_to_cpu(header->h_hash);
2979 int reusable = le32_to_cpu(header->h_refcount) <
2980 EXT4_XATTR_REFCOUNT_MAX;
2981 int error;
2982
2983 if (!ea_block_cache)
2984 return;
2985 error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2986 bh->b_blocknr, reusable);
2987 if (error) {
2988 if (error == -EBUSY)
2989 ea_bdebug(bh, "already in cache");
2990 } else
2991 ea_bdebug(bh, "inserting [%x]", (int)hash);
2992}
2993
2994/*
2995 * ext4_xattr_cmp()
2996 *
2997 * Compare two extended attribute blocks for equality.
2998 *
2999 * Returns 0 if the blocks are equal, 1 if they differ, and
3000 * a negative error number on errors.
3001 */
3002static int
3003ext4_xattr_cmp(struct ext4_xattr_header *header1,
3004 struct ext4_xattr_header *header2)
3005{
3006 struct ext4_xattr_entry *entry1, *entry2;
3007
3008 entry1 = ENTRY(header1+1);
3009 entry2 = ENTRY(header2+1);
3010 while (!IS_LAST_ENTRY(entry1)) {
3011 if (IS_LAST_ENTRY(entry2))
3012 return 1;
3013 if (entry1->e_hash != entry2->e_hash ||
3014 entry1->e_name_index != entry2->e_name_index ||
3015 entry1->e_name_len != entry2->e_name_len ||
3016 entry1->e_value_size != entry2->e_value_size ||
3017 entry1->e_value_inum != entry2->e_value_inum ||
3018 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3019 return 1;
3020 if (!entry1->e_value_inum &&
3021 memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3022 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3023 le32_to_cpu(entry1->e_value_size)))
3024 return 1;
3025
3026 entry1 = EXT4_XATTR_NEXT(entry1);
3027 entry2 = EXT4_XATTR_NEXT(entry2);
3028 }
3029 if (!IS_LAST_ENTRY(entry2))
3030 return 1;
3031 return 0;
3032}
3033
3034/*
3035 * ext4_xattr_block_cache_find()
3036 *
3037 * Find an identical extended attribute block.
3038 *
3039 * Returns a pointer to the block found, or NULL if such a block was
3040 * not found or an error occurred.
3041 */
3042static struct buffer_head *
3043ext4_xattr_block_cache_find(struct inode *inode,
3044 struct ext4_xattr_header *header,
3045 struct mb_cache_entry **pce)
3046{
3047 __u32 hash = le32_to_cpu(header->h_hash);
3048 struct mb_cache_entry *ce;
3049 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3050
3051 if (!ea_block_cache)
3052 return NULL;
3053 if (!header->h_hash)
3054 return NULL; /* never share */
3055 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3056 ce = mb_cache_entry_find_first(ea_block_cache, hash);
3057 while (ce) {
3058 struct buffer_head *bh;
3059
3060 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3061 if (IS_ERR(bh)) {
3062 if (PTR_ERR(bh) == -ENOMEM)
3063 return NULL;
3064 bh = NULL;
3065 EXT4_ERROR_INODE(inode, "block %lu read error",
3066 (unsigned long)ce->e_value);
3067 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3068 *pce = ce;
3069 return bh;
3070 }
3071 brelse(bh);
3072 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3073 }
3074 return NULL;
3075}
3076
3077#define NAME_HASH_SHIFT 5
3078#define VALUE_HASH_SHIFT 16
3079
3080/*
3081 * ext4_xattr_hash_entry()
3082 *
3083 * Compute the hash of an extended attribute.
3084 */
3085static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3086 size_t value_count)
3087{
3088 __u32 hash = 0;
3089
3090 while (name_len--) {
3091 hash = (hash << NAME_HASH_SHIFT) ^
3092 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3093 *name++;
3094 }
3095 while (value_count--) {
3096 hash = (hash << VALUE_HASH_SHIFT) ^
3097 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3098 le32_to_cpu(*value++);
3099 }
3100 return cpu_to_le32(hash);
3101}
3102
3103#undef NAME_HASH_SHIFT
3104#undef VALUE_HASH_SHIFT
3105
3106#define BLOCK_HASH_SHIFT 16
3107
3108/*
3109 * ext4_xattr_rehash()
3110 *
3111 * Re-compute the extended attribute hash value after an entry has changed.
3112 */
3113static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3114{
3115 struct ext4_xattr_entry *here;
3116 __u32 hash = 0;
3117
3118 here = ENTRY(header+1);
3119 while (!IS_LAST_ENTRY(here)) {
3120 if (!here->e_hash) {
3121 /* Block is not shared if an entry's hash value == 0 */
3122 hash = 0;
3123 break;
3124 }
3125 hash = (hash << BLOCK_HASH_SHIFT) ^
3126 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3127 le32_to_cpu(here->e_hash);
3128 here = EXT4_XATTR_NEXT(here);
3129 }
3130 header->h_hash = cpu_to_le32(hash);
3131}
3132
3133#undef BLOCK_HASH_SHIFT
3134
3135#define HASH_BUCKET_BITS 10
3136
3137struct mb_cache *
3138ext4_xattr_create_cache(void)
3139{
3140 return mb_cache_create(HASH_BUCKET_BITS);
3141}
3142
3143void ext4_xattr_destroy_cache(struct mb_cache *cache)
3144{
3145 if (cache)
3146 mb_cache_destroy(cache);
3147}
3148