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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/*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16/*
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53#include <linux/init.h>
54#include <linux/fs.h>
55#include <linux/slab.h>
56#include <linux/mbcache.h>
57#include <linux/quotaops.h>
58#include "ext4_jbd2.h"
59#include "ext4.h"
60#include "xattr.h"
61#include "acl.h"
62
63#ifdef EXT4_XATTR_DEBUG
64# define ea_idebug(inode, f...) do { \
65 printk(KERN_DEBUG "inode %s:%lu: ", \
66 inode->i_sb->s_id, inode->i_ino); \
67 printk(f); \
68 printk("\n"); \
69 } while (0)
70# define ea_bdebug(bh, f...) do { \
71 printk(KERN_DEBUG "block %pg:%lu: ", \
72 bh->b_bdev, (unsigned long) bh->b_blocknr); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76#else
77# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
78# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
79#endif
80
81static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
82static struct buffer_head *ext4_xattr_cache_find(struct inode *,
83 struct ext4_xattr_header *,
84 struct mb_cache_entry **);
85static void ext4_xattr_rehash(struct ext4_xattr_header *,
86 struct ext4_xattr_entry *);
87static int ext4_xattr_list(struct dentry *dentry, char *buffer,
88 size_t buffer_size);
89
90static const struct xattr_handler *ext4_xattr_handler_map[] = {
91 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
92#ifdef CONFIG_EXT4_FS_POSIX_ACL
93 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
94 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
95#endif
96 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
97#ifdef CONFIG_EXT4_FS_SECURITY
98 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
99#endif
100};
101
102const struct xattr_handler *ext4_xattr_handlers[] = {
103 &ext4_xattr_user_handler,
104 &ext4_xattr_trusted_handler,
105#ifdef CONFIG_EXT4_FS_POSIX_ACL
106 &posix_acl_access_xattr_handler,
107 &posix_acl_default_xattr_handler,
108#endif
109#ifdef CONFIG_EXT4_FS_SECURITY
110 &ext4_xattr_security_handler,
111#endif
112 NULL
113};
114
115#define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \
116 inode->i_sb->s_fs_info)->s_mb_cache)
117
118static __le32 ext4_xattr_block_csum(struct inode *inode,
119 sector_t block_nr,
120 struct ext4_xattr_header *hdr)
121{
122 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
123 __u32 csum;
124 __le32 save_csum;
125 __le64 dsk_block_nr = cpu_to_le64(block_nr);
126
127 save_csum = hdr->h_checksum;
128 hdr->h_checksum = 0;
129 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
130 sizeof(dsk_block_nr));
131 csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
132 EXT4_BLOCK_SIZE(inode->i_sb));
133
134 hdr->h_checksum = save_csum;
135 return cpu_to_le32(csum);
136}
137
138static int ext4_xattr_block_csum_verify(struct inode *inode,
139 sector_t block_nr,
140 struct ext4_xattr_header *hdr)
141{
142 if (ext4_has_metadata_csum(inode->i_sb) &&
143 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
144 return 0;
145 return 1;
146}
147
148static void ext4_xattr_block_csum_set(struct inode *inode,
149 sector_t block_nr,
150 struct ext4_xattr_header *hdr)
151{
152 if (!ext4_has_metadata_csum(inode->i_sb))
153 return;
154
155 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
156}
157
158static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
159 struct inode *inode,
160 struct buffer_head *bh)
161{
162 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
163 return ext4_handle_dirty_metadata(handle, inode, bh);
164}
165
166static inline const struct xattr_handler *
167ext4_xattr_handler(int name_index)
168{
169 const struct xattr_handler *handler = NULL;
170
171 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
172 handler = ext4_xattr_handler_map[name_index];
173 return handler;
174}
175
176/*
177 * Inode operation listxattr()
178 *
179 * d_inode(dentry)->i_mutex: don't care
180 */
181ssize_t
182ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
183{
184 return ext4_xattr_list(dentry, buffer, size);
185}
186
187static int
188ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
189 void *value_start)
190{
191 struct ext4_xattr_entry *e = entry;
192
193 while (!IS_LAST_ENTRY(e)) {
194 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
195 if ((void *)next >= end)
196 return -EFSCORRUPTED;
197 e = next;
198 }
199
200 while (!IS_LAST_ENTRY(entry)) {
201 if (entry->e_value_size != 0 &&
202 (value_start + le16_to_cpu(entry->e_value_offs) <
203 (void *)e + sizeof(__u32) ||
204 value_start + le16_to_cpu(entry->e_value_offs) +
205 le32_to_cpu(entry->e_value_size) > end))
206 return -EFSCORRUPTED;
207 entry = EXT4_XATTR_NEXT(entry);
208 }
209
210 return 0;
211}
212
213static inline int
214ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
215{
216 int error;
217
218 if (buffer_verified(bh))
219 return 0;
220
221 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
222 BHDR(bh)->h_blocks != cpu_to_le32(1))
223 return -EFSCORRUPTED;
224 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
225 return -EFSBADCRC;
226 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
227 bh->b_data);
228 if (!error)
229 set_buffer_verified(bh);
230 return error;
231}
232
233static int
234__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
235 void *end, const char *function, unsigned int line)
236{
237 struct ext4_xattr_entry *entry = IFIRST(header);
238 int error = -EFSCORRUPTED;
239
240 if (((void *) header >= end) ||
241 (header->h_magic != le32_to_cpu(EXT4_XATTR_MAGIC)))
242 goto errout;
243 error = ext4_xattr_check_names(entry, end, entry);
244errout:
245 if (error)
246 __ext4_error_inode(inode, function, line, 0,
247 "corrupted in-inode xattr");
248 return error;
249}
250
251#define xattr_check_inode(inode, header, end) \
252 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
253
254static inline int
255ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
256{
257 size_t value_size = le32_to_cpu(entry->e_value_size);
258
259 if (entry->e_value_block != 0 || value_size > size ||
260 le16_to_cpu(entry->e_value_offs) + value_size > size)
261 return -EFSCORRUPTED;
262 return 0;
263}
264
265static int
266ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
267 const char *name, size_t size, int sorted)
268{
269 struct ext4_xattr_entry *entry;
270 size_t name_len;
271 int cmp = 1;
272
273 if (name == NULL)
274 return -EINVAL;
275 name_len = strlen(name);
276 entry = *pentry;
277 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
278 cmp = name_index - entry->e_name_index;
279 if (!cmp)
280 cmp = name_len - entry->e_name_len;
281 if (!cmp)
282 cmp = memcmp(name, entry->e_name, name_len);
283 if (cmp <= 0 && (sorted || cmp == 0))
284 break;
285 }
286 *pentry = entry;
287 if (!cmp && ext4_xattr_check_entry(entry, size))
288 return -EFSCORRUPTED;
289 return cmp ? -ENODATA : 0;
290}
291
292static int
293ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
294 void *buffer, size_t buffer_size)
295{
296 struct buffer_head *bh = NULL;
297 struct ext4_xattr_entry *entry;
298 size_t size;
299 int error;
300 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
301
302 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
303 name_index, name, buffer, (long)buffer_size);
304
305 error = -ENODATA;
306 if (!EXT4_I(inode)->i_file_acl)
307 goto cleanup;
308 ea_idebug(inode, "reading block %llu",
309 (unsigned long long)EXT4_I(inode)->i_file_acl);
310 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
311 if (!bh)
312 goto cleanup;
313 ea_bdebug(bh, "b_count=%d, refcount=%d",
314 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
315 if (ext4_xattr_check_block(inode, bh)) {
316bad_block:
317 EXT4_ERROR_INODE(inode, "bad block %llu",
318 EXT4_I(inode)->i_file_acl);
319 error = -EFSCORRUPTED;
320 goto cleanup;
321 }
322 ext4_xattr_cache_insert(ext4_mb_cache, bh);
323 entry = BFIRST(bh);
324 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
325 if (error == -EFSCORRUPTED)
326 goto bad_block;
327 if (error)
328 goto cleanup;
329 size = le32_to_cpu(entry->e_value_size);
330 if (buffer) {
331 error = -ERANGE;
332 if (size > buffer_size)
333 goto cleanup;
334 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
335 size);
336 }
337 error = size;
338
339cleanup:
340 brelse(bh);
341 return error;
342}
343
344int
345ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
346 void *buffer, size_t buffer_size)
347{
348 struct ext4_xattr_ibody_header *header;
349 struct ext4_xattr_entry *entry;
350 struct ext4_inode *raw_inode;
351 struct ext4_iloc iloc;
352 size_t size;
353 void *end;
354 int error;
355
356 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
357 return -ENODATA;
358 error = ext4_get_inode_loc(inode, &iloc);
359 if (error)
360 return error;
361 raw_inode = ext4_raw_inode(&iloc);
362 header = IHDR(inode, raw_inode);
363 entry = IFIRST(header);
364 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
365 error = xattr_check_inode(inode, header, end);
366 if (error)
367 goto cleanup;
368 error = ext4_xattr_find_entry(&entry, name_index, name,
369 end - (void *)entry, 0);
370 if (error)
371 goto cleanup;
372 size = le32_to_cpu(entry->e_value_size);
373 if (buffer) {
374 error = -ERANGE;
375 if (size > buffer_size)
376 goto cleanup;
377 memcpy(buffer, (void *)IFIRST(header) +
378 le16_to_cpu(entry->e_value_offs), size);
379 }
380 error = size;
381
382cleanup:
383 brelse(iloc.bh);
384 return error;
385}
386
387/*
388 * ext4_xattr_get()
389 *
390 * Copy an extended attribute into the buffer
391 * provided, or compute the buffer size required.
392 * Buffer is NULL to compute the size of the buffer required.
393 *
394 * Returns a negative error number on failure, or the number of bytes
395 * used / required on success.
396 */
397int
398ext4_xattr_get(struct inode *inode, int name_index, const char *name,
399 void *buffer, size_t buffer_size)
400{
401 int error;
402
403 if (strlen(name) > 255)
404 return -ERANGE;
405
406 down_read(&EXT4_I(inode)->xattr_sem);
407 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
408 buffer_size);
409 if (error == -ENODATA)
410 error = ext4_xattr_block_get(inode, name_index, name, buffer,
411 buffer_size);
412 up_read(&EXT4_I(inode)->xattr_sem);
413 return error;
414}
415
416static int
417ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
418 char *buffer, size_t buffer_size)
419{
420 size_t rest = buffer_size;
421
422 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
423 const struct xattr_handler *handler =
424 ext4_xattr_handler(entry->e_name_index);
425
426 if (handler && (!handler->list || handler->list(dentry))) {
427 const char *prefix = handler->prefix ?: handler->name;
428 size_t prefix_len = strlen(prefix);
429 size_t size = prefix_len + entry->e_name_len + 1;
430
431 if (buffer) {
432 if (size > rest)
433 return -ERANGE;
434 memcpy(buffer, prefix, prefix_len);
435 buffer += prefix_len;
436 memcpy(buffer, entry->e_name, entry->e_name_len);
437 buffer += entry->e_name_len;
438 *buffer++ = 0;
439 }
440 rest -= size;
441 }
442 }
443 return buffer_size - rest; /* total size */
444}
445
446static int
447ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
448{
449 struct inode *inode = d_inode(dentry);
450 struct buffer_head *bh = NULL;
451 int error;
452 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
453
454 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
455 buffer, (long)buffer_size);
456
457 error = 0;
458 if (!EXT4_I(inode)->i_file_acl)
459 goto cleanup;
460 ea_idebug(inode, "reading block %llu",
461 (unsigned long long)EXT4_I(inode)->i_file_acl);
462 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
463 error = -EIO;
464 if (!bh)
465 goto cleanup;
466 ea_bdebug(bh, "b_count=%d, refcount=%d",
467 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
468 if (ext4_xattr_check_block(inode, bh)) {
469 EXT4_ERROR_INODE(inode, "bad block %llu",
470 EXT4_I(inode)->i_file_acl);
471 error = -EFSCORRUPTED;
472 goto cleanup;
473 }
474 ext4_xattr_cache_insert(ext4_mb_cache, bh);
475 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
476
477cleanup:
478 brelse(bh);
479
480 return error;
481}
482
483static int
484ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
485{
486 struct inode *inode = d_inode(dentry);
487 struct ext4_xattr_ibody_header *header;
488 struct ext4_inode *raw_inode;
489 struct ext4_iloc iloc;
490 void *end;
491 int error;
492
493 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
494 return 0;
495 error = ext4_get_inode_loc(inode, &iloc);
496 if (error)
497 return error;
498 raw_inode = ext4_raw_inode(&iloc);
499 header = IHDR(inode, raw_inode);
500 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
501 error = xattr_check_inode(inode, header, end);
502 if (error)
503 goto cleanup;
504 error = ext4_xattr_list_entries(dentry, IFIRST(header),
505 buffer, buffer_size);
506
507cleanup:
508 brelse(iloc.bh);
509 return error;
510}
511
512/*
513 * ext4_xattr_list()
514 *
515 * Copy a list of attribute names into the buffer
516 * provided, or compute the buffer size required.
517 * Buffer is NULL to compute the size of the buffer required.
518 *
519 * Returns a negative error number on failure, or the number of bytes
520 * used / required on success.
521 */
522static int
523ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
524{
525 int ret, ret2;
526
527 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
528 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
529 if (ret < 0)
530 goto errout;
531 if (buffer) {
532 buffer += ret;
533 buffer_size -= ret;
534 }
535 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
536 if (ret < 0)
537 goto errout;
538 ret += ret2;
539errout:
540 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
541 return ret;
542}
543
544/*
545 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
546 * not set, set it.
547 */
548static void ext4_xattr_update_super_block(handle_t *handle,
549 struct super_block *sb)
550{
551 if (ext4_has_feature_xattr(sb))
552 return;
553
554 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
555 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
556 ext4_set_feature_xattr(sb);
557 ext4_handle_dirty_super(handle, sb);
558 }
559}
560
561/*
562 * Release the xattr block BH: If the reference count is > 1, decrement it;
563 * otherwise free the block.
564 */
565static void
566ext4_xattr_release_block(handle_t *handle, struct inode *inode,
567 struct buffer_head *bh)
568{
569 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
570 u32 hash, ref;
571 int error = 0;
572
573 BUFFER_TRACE(bh, "get_write_access");
574 error = ext4_journal_get_write_access(handle, bh);
575 if (error)
576 goto out;
577
578 lock_buffer(bh);
579 hash = le32_to_cpu(BHDR(bh)->h_hash);
580 ref = le32_to_cpu(BHDR(bh)->h_refcount);
581 if (ref == 1) {
582 ea_bdebug(bh, "refcount now=0; freeing");
583 /*
584 * This must happen under buffer lock for
585 * ext4_xattr_block_set() to reliably detect freed block
586 */
587 mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
588 get_bh(bh);
589 unlock_buffer(bh);
590 ext4_free_blocks(handle, inode, bh, 0, 1,
591 EXT4_FREE_BLOCKS_METADATA |
592 EXT4_FREE_BLOCKS_FORGET);
593 } else {
594 ref--;
595 BHDR(bh)->h_refcount = cpu_to_le32(ref);
596 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
597 struct mb_cache_entry *ce;
598
599 ce = mb_cache_entry_get(ext4_mb_cache, hash,
600 bh->b_blocknr);
601 if (ce) {
602 ce->e_reusable = 1;
603 mb_cache_entry_put(ext4_mb_cache, ce);
604 }
605 }
606
607 /*
608 * Beware of this ugliness: Releasing of xattr block references
609 * from different inodes can race and so we have to protect
610 * from a race where someone else frees the block (and releases
611 * its journal_head) before we are done dirtying the buffer. In
612 * nojournal mode this race is harmless and we actually cannot
613 * call ext4_handle_dirty_xattr_block() with locked buffer as
614 * that function can call sync_dirty_buffer() so for that case
615 * we handle the dirtying after unlocking the buffer.
616 */
617 if (ext4_handle_valid(handle))
618 error = ext4_handle_dirty_xattr_block(handle, inode,
619 bh);
620 unlock_buffer(bh);
621 if (!ext4_handle_valid(handle))
622 error = ext4_handle_dirty_xattr_block(handle, inode,
623 bh);
624 if (IS_SYNC(inode))
625 ext4_handle_sync(handle);
626 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
627 ea_bdebug(bh, "refcount now=%d; releasing",
628 le32_to_cpu(BHDR(bh)->h_refcount));
629 }
630out:
631 ext4_std_error(inode->i_sb, error);
632 return;
633}
634
635/*
636 * Find the available free space for EAs. This also returns the total number of
637 * bytes used by EA entries.
638 */
639static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
640 size_t *min_offs, void *base, int *total)
641{
642 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
643 if (!last->e_value_block && last->e_value_size) {
644 size_t offs = le16_to_cpu(last->e_value_offs);
645 if (offs < *min_offs)
646 *min_offs = offs;
647 }
648 if (total)
649 *total += EXT4_XATTR_LEN(last->e_name_len);
650 }
651 return (*min_offs - ((void *)last - base) - sizeof(__u32));
652}
653
654static int
655ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
656{
657 struct ext4_xattr_entry *last;
658 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
659
660 /* Compute min_offs and last. */
661 last = s->first;
662 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
663 if (!last->e_value_block && last->e_value_size) {
664 size_t offs = le16_to_cpu(last->e_value_offs);
665 if (offs < min_offs)
666 min_offs = offs;
667 }
668 }
669 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
670 if (!s->not_found) {
671 if (!s->here->e_value_block && s->here->e_value_size) {
672 size_t size = le32_to_cpu(s->here->e_value_size);
673 free += EXT4_XATTR_SIZE(size);
674 }
675 free += EXT4_XATTR_LEN(name_len);
676 }
677 if (i->value) {
678 if (free < EXT4_XATTR_LEN(name_len) +
679 EXT4_XATTR_SIZE(i->value_len))
680 return -ENOSPC;
681 }
682
683 if (i->value && s->not_found) {
684 /* Insert the new name. */
685 size_t size = EXT4_XATTR_LEN(name_len);
686 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
687 memmove((void *)s->here + size, s->here, rest);
688 memset(s->here, 0, size);
689 s->here->e_name_index = i->name_index;
690 s->here->e_name_len = name_len;
691 memcpy(s->here->e_name, i->name, name_len);
692 } else {
693 if (!s->here->e_value_block && s->here->e_value_size) {
694 void *first_val = s->base + min_offs;
695 size_t offs = le16_to_cpu(s->here->e_value_offs);
696 void *val = s->base + offs;
697 size_t size = EXT4_XATTR_SIZE(
698 le32_to_cpu(s->here->e_value_size));
699
700 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
701 /* The old and the new value have the same
702 size. Just replace. */
703 s->here->e_value_size =
704 cpu_to_le32(i->value_len);
705 if (i->value == EXT4_ZERO_XATTR_VALUE) {
706 memset(val, 0, size);
707 } else {
708 /* Clear pad bytes first. */
709 memset(val + size - EXT4_XATTR_PAD, 0,
710 EXT4_XATTR_PAD);
711 memcpy(val, i->value, i->value_len);
712 }
713 return 0;
714 }
715
716 /* Remove the old value. */
717 memmove(first_val + size, first_val, val - first_val);
718 memset(first_val, 0, size);
719 s->here->e_value_size = 0;
720 s->here->e_value_offs = 0;
721 min_offs += size;
722
723 /* Adjust all value offsets. */
724 last = s->first;
725 while (!IS_LAST_ENTRY(last)) {
726 size_t o = le16_to_cpu(last->e_value_offs);
727 if (!last->e_value_block &&
728 last->e_value_size && o < offs)
729 last->e_value_offs =
730 cpu_to_le16(o + size);
731 last = EXT4_XATTR_NEXT(last);
732 }
733 }
734 if (!i->value) {
735 /* Remove the old name. */
736 size_t size = EXT4_XATTR_LEN(name_len);
737 last = ENTRY((void *)last - size);
738 memmove(s->here, (void *)s->here + size,
739 (void *)last - (void *)s->here + sizeof(__u32));
740 memset(last, 0, size);
741 }
742 }
743
744 if (i->value) {
745 /* Insert the new value. */
746 s->here->e_value_size = cpu_to_le32(i->value_len);
747 if (i->value_len) {
748 size_t size = EXT4_XATTR_SIZE(i->value_len);
749 void *val = s->base + min_offs - size;
750 s->here->e_value_offs = cpu_to_le16(min_offs - size);
751 if (i->value == EXT4_ZERO_XATTR_VALUE) {
752 memset(val, 0, size);
753 } else {
754 /* Clear the pad bytes first. */
755 memset(val + size - EXT4_XATTR_PAD, 0,
756 EXT4_XATTR_PAD);
757 memcpy(val, i->value, i->value_len);
758 }
759 }
760 }
761 return 0;
762}
763
764struct ext4_xattr_block_find {
765 struct ext4_xattr_search s;
766 struct buffer_head *bh;
767};
768
769static int
770ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
771 struct ext4_xattr_block_find *bs)
772{
773 struct super_block *sb = inode->i_sb;
774 int error;
775
776 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
777 i->name_index, i->name, i->value, (long)i->value_len);
778
779 if (EXT4_I(inode)->i_file_acl) {
780 /* The inode already has an extended attribute block. */
781 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
782 error = -EIO;
783 if (!bs->bh)
784 goto cleanup;
785 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
786 atomic_read(&(bs->bh->b_count)),
787 le32_to_cpu(BHDR(bs->bh)->h_refcount));
788 if (ext4_xattr_check_block(inode, bs->bh)) {
789 EXT4_ERROR_INODE(inode, "bad block %llu",
790 EXT4_I(inode)->i_file_acl);
791 error = -EFSCORRUPTED;
792 goto cleanup;
793 }
794 /* Find the named attribute. */
795 bs->s.base = BHDR(bs->bh);
796 bs->s.first = BFIRST(bs->bh);
797 bs->s.end = bs->bh->b_data + bs->bh->b_size;
798 bs->s.here = bs->s.first;
799 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
800 i->name, bs->bh->b_size, 1);
801 if (error && error != -ENODATA)
802 goto cleanup;
803 bs->s.not_found = error;
804 }
805 error = 0;
806
807cleanup:
808 return error;
809}
810
811static int
812ext4_xattr_block_set(handle_t *handle, struct inode *inode,
813 struct ext4_xattr_info *i,
814 struct ext4_xattr_block_find *bs)
815{
816 struct super_block *sb = inode->i_sb;
817 struct buffer_head *new_bh = NULL;
818 struct ext4_xattr_search *s = &bs->s;
819 struct mb_cache_entry *ce = NULL;
820 int error = 0;
821 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
822
823#define header(x) ((struct ext4_xattr_header *)(x))
824
825 if (i->value && i->value_len > sb->s_blocksize)
826 return -ENOSPC;
827 if (s->base) {
828 BUFFER_TRACE(bs->bh, "get_write_access");
829 error = ext4_journal_get_write_access(handle, bs->bh);
830 if (error)
831 goto cleanup;
832 lock_buffer(bs->bh);
833
834 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
835 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
836
837 /*
838 * This must happen under buffer lock for
839 * ext4_xattr_block_set() to reliably detect modified
840 * block
841 */
842 mb_cache_entry_delete_block(ext4_mb_cache, hash,
843 bs->bh->b_blocknr);
844 ea_bdebug(bs->bh, "modifying in-place");
845 error = ext4_xattr_set_entry(i, s);
846 if (!error) {
847 if (!IS_LAST_ENTRY(s->first))
848 ext4_xattr_rehash(header(s->base),
849 s->here);
850 ext4_xattr_cache_insert(ext4_mb_cache,
851 bs->bh);
852 }
853 unlock_buffer(bs->bh);
854 if (error == -EFSCORRUPTED)
855 goto bad_block;
856 if (!error)
857 error = ext4_handle_dirty_xattr_block(handle,
858 inode,
859 bs->bh);
860 if (error)
861 goto cleanup;
862 goto inserted;
863 } else {
864 int offset = (char *)s->here - bs->bh->b_data;
865
866 unlock_buffer(bs->bh);
867 ea_bdebug(bs->bh, "cloning");
868 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
869 error = -ENOMEM;
870 if (s->base == NULL)
871 goto cleanup;
872 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
873 s->first = ENTRY(header(s->base)+1);
874 header(s->base)->h_refcount = cpu_to_le32(1);
875 s->here = ENTRY(s->base + offset);
876 s->end = s->base + bs->bh->b_size;
877 }
878 } else {
879 /* Allocate a buffer where we construct the new block. */
880 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
881 /* assert(header == s->base) */
882 error = -ENOMEM;
883 if (s->base == NULL)
884 goto cleanup;
885 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
886 header(s->base)->h_blocks = cpu_to_le32(1);
887 header(s->base)->h_refcount = cpu_to_le32(1);
888 s->first = ENTRY(header(s->base)+1);
889 s->here = ENTRY(header(s->base)+1);
890 s->end = s->base + sb->s_blocksize;
891 }
892
893 error = ext4_xattr_set_entry(i, s);
894 if (error == -EFSCORRUPTED)
895 goto bad_block;
896 if (error)
897 goto cleanup;
898 if (!IS_LAST_ENTRY(s->first))
899 ext4_xattr_rehash(header(s->base), s->here);
900
901inserted:
902 if (!IS_LAST_ENTRY(s->first)) {
903 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
904 if (new_bh) {
905 /* We found an identical block in the cache. */
906 if (new_bh == bs->bh)
907 ea_bdebug(new_bh, "keeping");
908 else {
909 u32 ref;
910
911 /* The old block is released after updating
912 the inode. */
913 error = dquot_alloc_block(inode,
914 EXT4_C2B(EXT4_SB(sb), 1));
915 if (error)
916 goto cleanup;
917 BUFFER_TRACE(new_bh, "get_write_access");
918 error = ext4_journal_get_write_access(handle,
919 new_bh);
920 if (error)
921 goto cleanup_dquot;
922 lock_buffer(new_bh);
923 /*
924 * We have to be careful about races with
925 * freeing, rehashing or adding references to
926 * xattr block. Once we hold buffer lock xattr
927 * block's state is stable so we can check
928 * whether the block got freed / rehashed or
929 * not. Since we unhash mbcache entry under
930 * buffer lock when freeing / rehashing xattr
931 * block, checking whether entry is still
932 * hashed is reliable. Same rules hold for
933 * e_reusable handling.
934 */
935 if (hlist_bl_unhashed(&ce->e_hash_list) ||
936 !ce->e_reusable) {
937 /*
938 * Undo everything and check mbcache
939 * again.
940 */
941 unlock_buffer(new_bh);
942 dquot_free_block(inode,
943 EXT4_C2B(EXT4_SB(sb),
944 1));
945 brelse(new_bh);
946 mb_cache_entry_put(ext4_mb_cache, ce);
947 ce = NULL;
948 new_bh = NULL;
949 goto inserted;
950 }
951 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
952 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
953 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
954 ce->e_reusable = 0;
955 ea_bdebug(new_bh, "reusing; refcount now=%d",
956 ref);
957 unlock_buffer(new_bh);
958 error = ext4_handle_dirty_xattr_block(handle,
959 inode,
960 new_bh);
961 if (error)
962 goto cleanup_dquot;
963 }
964 mb_cache_entry_touch(ext4_mb_cache, ce);
965 mb_cache_entry_put(ext4_mb_cache, ce);
966 ce = NULL;
967 } else if (bs->bh && s->base == bs->bh->b_data) {
968 /* We were modifying this block in-place. */
969 ea_bdebug(bs->bh, "keeping this block");
970 new_bh = bs->bh;
971 get_bh(new_bh);
972 } else {
973 /* We need to allocate a new block */
974 ext4_fsblk_t goal, block;
975
976 goal = ext4_group_first_block_no(sb,
977 EXT4_I(inode)->i_block_group);
978
979 /* non-extent files can't have physical blocks past 2^32 */
980 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
981 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
982
983 block = ext4_new_meta_blocks(handle, inode, goal, 0,
984 NULL, &error);
985 if (error)
986 goto cleanup;
987
988 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
989 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
990
991 ea_idebug(inode, "creating block %llu",
992 (unsigned long long)block);
993
994 new_bh = sb_getblk(sb, block);
995 if (unlikely(!new_bh)) {
996 error = -ENOMEM;
997getblk_failed:
998 ext4_free_blocks(handle, inode, NULL, block, 1,
999 EXT4_FREE_BLOCKS_METADATA);
1000 goto cleanup;
1001 }
1002 lock_buffer(new_bh);
1003 error = ext4_journal_get_create_access(handle, new_bh);
1004 if (error) {
1005 unlock_buffer(new_bh);
1006 error = -EIO;
1007 goto getblk_failed;
1008 }
1009 memcpy(new_bh->b_data, s->base, new_bh->b_size);
1010 set_buffer_uptodate(new_bh);
1011 unlock_buffer(new_bh);
1012 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1013 error = ext4_handle_dirty_xattr_block(handle,
1014 inode, new_bh);
1015 if (error)
1016 goto cleanup;
1017 }
1018 }
1019
1020 /* Update the inode. */
1021 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1022
1023 /* Drop the previous xattr block. */
1024 if (bs->bh && bs->bh != new_bh)
1025 ext4_xattr_release_block(handle, inode, bs->bh);
1026 error = 0;
1027
1028cleanup:
1029 if (ce)
1030 mb_cache_entry_put(ext4_mb_cache, ce);
1031 brelse(new_bh);
1032 if (!(bs->bh && s->base == bs->bh->b_data))
1033 kfree(s->base);
1034
1035 return error;
1036
1037cleanup_dquot:
1038 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1039 goto cleanup;
1040
1041bad_block:
1042 EXT4_ERROR_INODE(inode, "bad block %llu",
1043 EXT4_I(inode)->i_file_acl);
1044 goto cleanup;
1045
1046#undef header
1047}
1048
1049int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
1050 struct ext4_xattr_ibody_find *is)
1051{
1052 struct ext4_xattr_ibody_header *header;
1053 struct ext4_inode *raw_inode;
1054 int error;
1055
1056 if (EXT4_I(inode)->i_extra_isize == 0)
1057 return 0;
1058 raw_inode = ext4_raw_inode(&is->iloc);
1059 header = IHDR(inode, raw_inode);
1060 is->s.base = is->s.first = IFIRST(header);
1061 is->s.here = is->s.first;
1062 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1063 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1064 error = xattr_check_inode(inode, header, is->s.end);
1065 if (error)
1066 return error;
1067 /* Find the named attribute. */
1068 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1069 i->name, is->s.end -
1070 (void *)is->s.base, 0);
1071 if (error && error != -ENODATA)
1072 return error;
1073 is->s.not_found = error;
1074 }
1075 return 0;
1076}
1077
1078int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1079 struct ext4_xattr_info *i,
1080 struct ext4_xattr_ibody_find *is)
1081{
1082 struct ext4_xattr_ibody_header *header;
1083 struct ext4_xattr_search *s = &is->s;
1084 int error;
1085
1086 if (EXT4_I(inode)->i_extra_isize == 0)
1087 return -ENOSPC;
1088 error = ext4_xattr_set_entry(i, s);
1089 if (error) {
1090 if (error == -ENOSPC &&
1091 ext4_has_inline_data(inode)) {
1092 error = ext4_try_to_evict_inline_data(handle, inode,
1093 EXT4_XATTR_LEN(strlen(i->name) +
1094 EXT4_XATTR_SIZE(i->value_len)));
1095 if (error)
1096 return error;
1097 error = ext4_xattr_ibody_find(inode, i, is);
1098 if (error)
1099 return error;
1100 error = ext4_xattr_set_entry(i, s);
1101 }
1102 if (error)
1103 return error;
1104 }
1105 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1106 if (!IS_LAST_ENTRY(s->first)) {
1107 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1108 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1109 } else {
1110 header->h_magic = cpu_to_le32(0);
1111 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1112 }
1113 return 0;
1114}
1115
1116static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1117 struct ext4_xattr_info *i,
1118 struct ext4_xattr_ibody_find *is)
1119{
1120 struct ext4_xattr_ibody_header *header;
1121 struct ext4_xattr_search *s = &is->s;
1122 int error;
1123
1124 if (EXT4_I(inode)->i_extra_isize == 0)
1125 return -ENOSPC;
1126 error = ext4_xattr_set_entry(i, s);
1127 if (error)
1128 return error;
1129 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1130 if (!IS_LAST_ENTRY(s->first)) {
1131 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1132 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1133 } else {
1134 header->h_magic = cpu_to_le32(0);
1135 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1136 }
1137 return 0;
1138}
1139
1140static int ext4_xattr_value_same(struct ext4_xattr_search *s,
1141 struct ext4_xattr_info *i)
1142{
1143 void *value;
1144
1145 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
1146 return 0;
1147 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
1148 return !memcmp(value, i->value, i->value_len);
1149}
1150
1151/*
1152 * ext4_xattr_set_handle()
1153 *
1154 * Create, replace or remove an extended attribute for this inode. Value
1155 * is NULL to remove an existing extended attribute, and non-NULL to
1156 * either replace an existing extended attribute, or create a new extended
1157 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1158 * specify that an extended attribute must exist and must not exist
1159 * previous to the call, respectively.
1160 *
1161 * Returns 0, or a negative error number on failure.
1162 */
1163int
1164ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1165 const char *name, const void *value, size_t value_len,
1166 int flags)
1167{
1168 struct ext4_xattr_info i = {
1169 .name_index = name_index,
1170 .name = name,
1171 .value = value,
1172 .value_len = value_len,
1173
1174 };
1175 struct ext4_xattr_ibody_find is = {
1176 .s = { .not_found = -ENODATA, },
1177 };
1178 struct ext4_xattr_block_find bs = {
1179 .s = { .not_found = -ENODATA, },
1180 };
1181 unsigned long no_expand;
1182 int error;
1183
1184 if (!name)
1185 return -EINVAL;
1186 if (strlen(name) > 255)
1187 return -ERANGE;
1188 down_write(&EXT4_I(inode)->xattr_sem);
1189 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1190 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1191
1192 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1193 if (error)
1194 goto cleanup;
1195
1196 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1197 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1198 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1199 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1200 }
1201
1202 error = ext4_xattr_ibody_find(inode, &i, &is);
1203 if (error)
1204 goto cleanup;
1205 if (is.s.not_found)
1206 error = ext4_xattr_block_find(inode, &i, &bs);
1207 if (error)
1208 goto cleanup;
1209 if (is.s.not_found && bs.s.not_found) {
1210 error = -ENODATA;
1211 if (flags & XATTR_REPLACE)
1212 goto cleanup;
1213 error = 0;
1214 if (!value)
1215 goto cleanup;
1216 } else {
1217 error = -EEXIST;
1218 if (flags & XATTR_CREATE)
1219 goto cleanup;
1220 }
1221 if (!value) {
1222 if (!is.s.not_found)
1223 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1224 else if (!bs.s.not_found)
1225 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1226 } else {
1227 error = 0;
1228 /* Xattr value did not change? Save us some work and bail out */
1229 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
1230 goto cleanup;
1231 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
1232 goto cleanup;
1233
1234 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1235 if (!error && !bs.s.not_found) {
1236 i.value = NULL;
1237 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1238 } else if (error == -ENOSPC) {
1239 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1240 error = ext4_xattr_block_find(inode, &i, &bs);
1241 if (error)
1242 goto cleanup;
1243 }
1244 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1245 if (error)
1246 goto cleanup;
1247 if (!is.s.not_found) {
1248 i.value = NULL;
1249 error = ext4_xattr_ibody_set(handle, inode, &i,
1250 &is);
1251 }
1252 }
1253 }
1254 if (!error) {
1255 ext4_xattr_update_super_block(handle, inode->i_sb);
1256 inode->i_ctime = ext4_current_time(inode);
1257 if (!value)
1258 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1259 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1260 /*
1261 * The bh is consumed by ext4_mark_iloc_dirty, even with
1262 * error != 0.
1263 */
1264 is.iloc.bh = NULL;
1265 if (IS_SYNC(inode))
1266 ext4_handle_sync(handle);
1267 }
1268
1269cleanup:
1270 brelse(is.iloc.bh);
1271 brelse(bs.bh);
1272 if (no_expand == 0)
1273 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1274 up_write(&EXT4_I(inode)->xattr_sem);
1275 return error;
1276}
1277
1278/*
1279 * ext4_xattr_set()
1280 *
1281 * Like ext4_xattr_set_handle, but start from an inode. This extended
1282 * attribute modification is a filesystem transaction by itself.
1283 *
1284 * Returns 0, or a negative error number on failure.
1285 */
1286int
1287ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1288 const void *value, size_t value_len, int flags)
1289{
1290 handle_t *handle;
1291 int error, retries = 0;
1292 int credits = ext4_jbd2_credits_xattr(inode);
1293
1294retry:
1295 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1296 if (IS_ERR(handle)) {
1297 error = PTR_ERR(handle);
1298 } else {
1299 int error2;
1300
1301 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1302 value, value_len, flags);
1303 error2 = ext4_journal_stop(handle);
1304 if (error == -ENOSPC &&
1305 ext4_should_retry_alloc(inode->i_sb, &retries))
1306 goto retry;
1307 if (error == 0)
1308 error = error2;
1309 }
1310
1311 return error;
1312}
1313
1314/*
1315 * Shift the EA entries in the inode to create space for the increased
1316 * i_extra_isize.
1317 */
1318static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1319 int value_offs_shift, void *to,
1320 void *from, size_t n, int blocksize)
1321{
1322 struct ext4_xattr_entry *last = entry;
1323 int new_offs;
1324
1325 /* Adjust the value offsets of the entries */
1326 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1327 if (!last->e_value_block && last->e_value_size) {
1328 new_offs = le16_to_cpu(last->e_value_offs) +
1329 value_offs_shift;
1330 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1331 > blocksize);
1332 last->e_value_offs = cpu_to_le16(new_offs);
1333 }
1334 }
1335 /* Shift the entries by n bytes */
1336 memmove(to, from, n);
1337}
1338
1339/*
1340 * Expand an inode by new_extra_isize bytes when EAs are present.
1341 * Returns 0 on success or negative error number on failure.
1342 */
1343int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1344 struct ext4_inode *raw_inode, handle_t *handle)
1345{
1346 struct ext4_xattr_ibody_header *header;
1347 struct ext4_xattr_entry *entry, *last, *first;
1348 struct buffer_head *bh = NULL;
1349 struct ext4_xattr_ibody_find *is = NULL;
1350 struct ext4_xattr_block_find *bs = NULL;
1351 char *buffer = NULL, *b_entry_name = NULL;
1352 size_t min_offs, free;
1353 int total_ino;
1354 void *base, *start, *end;
1355 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1356 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1357
1358 down_write(&EXT4_I(inode)->xattr_sem);
1359retry:
1360 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1361 up_write(&EXT4_I(inode)->xattr_sem);
1362 return 0;
1363 }
1364
1365 header = IHDR(inode, raw_inode);
1366 entry = IFIRST(header);
1367
1368 /*
1369 * Check if enough free space is available in the inode to shift the
1370 * entries ahead by new_extra_isize.
1371 */
1372
1373 base = start = entry;
1374 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1375 min_offs = end - base;
1376 last = entry;
1377 total_ino = sizeof(struct ext4_xattr_ibody_header);
1378
1379 error = xattr_check_inode(inode, header, end);
1380 if (error)
1381 goto cleanup;
1382
1383 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1384 if (free >= new_extra_isize) {
1385 entry = IFIRST(header);
1386 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1387 - new_extra_isize, (void *)raw_inode +
1388 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1389 (void *)header, total_ino,
1390 inode->i_sb->s_blocksize);
1391 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1392 error = 0;
1393 goto cleanup;
1394 }
1395
1396 /*
1397 * Enough free space isn't available in the inode, check if
1398 * EA block can hold new_extra_isize bytes.
1399 */
1400 if (EXT4_I(inode)->i_file_acl) {
1401 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1402 error = -EIO;
1403 if (!bh)
1404 goto cleanup;
1405 if (ext4_xattr_check_block(inode, bh)) {
1406 EXT4_ERROR_INODE(inode, "bad block %llu",
1407 EXT4_I(inode)->i_file_acl);
1408 error = -EFSCORRUPTED;
1409 goto cleanup;
1410 }
1411 base = BHDR(bh);
1412 first = BFIRST(bh);
1413 end = bh->b_data + bh->b_size;
1414 min_offs = end - base;
1415 free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1416 if (free < new_extra_isize) {
1417 if (!tried_min_extra_isize && s_min_extra_isize) {
1418 tried_min_extra_isize++;
1419 new_extra_isize = s_min_extra_isize;
1420 brelse(bh);
1421 goto retry;
1422 }
1423 error = -1;
1424 goto cleanup;
1425 }
1426 } else {
1427 free = inode->i_sb->s_blocksize;
1428 }
1429
1430 while (new_extra_isize > 0) {
1431 size_t offs, size, entry_size;
1432 struct ext4_xattr_entry *small_entry = NULL;
1433 struct ext4_xattr_info i = {
1434 .value = NULL,
1435 .value_len = 0,
1436 };
1437 unsigned int total_size; /* EA entry size + value size */
1438 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1439 unsigned int min_total_size = ~0U;
1440
1441 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1442 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1443 if (!is || !bs) {
1444 error = -ENOMEM;
1445 goto cleanup;
1446 }
1447
1448 is->s.not_found = -ENODATA;
1449 bs->s.not_found = -ENODATA;
1450 is->iloc.bh = NULL;
1451 bs->bh = NULL;
1452
1453 last = IFIRST(header);
1454 /* Find the entry best suited to be pushed into EA block */
1455 entry = NULL;
1456 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1457 total_size =
1458 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1459 EXT4_XATTR_LEN(last->e_name_len);
1460 if (total_size <= free && total_size < min_total_size) {
1461 if (total_size < new_extra_isize) {
1462 small_entry = last;
1463 } else {
1464 entry = last;
1465 min_total_size = total_size;
1466 }
1467 }
1468 }
1469
1470 if (entry == NULL) {
1471 if (small_entry) {
1472 entry = small_entry;
1473 } else {
1474 if (!tried_min_extra_isize &&
1475 s_min_extra_isize) {
1476 tried_min_extra_isize++;
1477 new_extra_isize = s_min_extra_isize;
1478 kfree(is); is = NULL;
1479 kfree(bs); bs = NULL;
1480 brelse(bh);
1481 goto retry;
1482 }
1483 error = -1;
1484 goto cleanup;
1485 }
1486 }
1487 offs = le16_to_cpu(entry->e_value_offs);
1488 size = le32_to_cpu(entry->e_value_size);
1489 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1490 i.name_index = entry->e_name_index,
1491 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1492 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1493 if (!buffer || !b_entry_name) {
1494 error = -ENOMEM;
1495 goto cleanup;
1496 }
1497 /* Save the entry name and the entry value */
1498 memcpy(buffer, (void *)IFIRST(header) + offs,
1499 EXT4_XATTR_SIZE(size));
1500 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1501 b_entry_name[entry->e_name_len] = '\0';
1502 i.name = b_entry_name;
1503
1504 error = ext4_get_inode_loc(inode, &is->iloc);
1505 if (error)
1506 goto cleanup;
1507
1508 error = ext4_xattr_ibody_find(inode, &i, is);
1509 if (error)
1510 goto cleanup;
1511
1512 /* Remove the chosen entry from the inode */
1513 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1514 if (error)
1515 goto cleanup;
1516
1517 entry = IFIRST(header);
1518 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1519 shift_bytes = new_extra_isize;
1520 else
1521 shift_bytes = entry_size + size;
1522 /* Adjust the offsets and shift the remaining entries ahead */
1523 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1524 shift_bytes, (void *)raw_inode +
1525 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1526 (void *)header, total_ino - entry_size,
1527 inode->i_sb->s_blocksize);
1528
1529 extra_isize += shift_bytes;
1530 new_extra_isize -= shift_bytes;
1531 EXT4_I(inode)->i_extra_isize = extra_isize;
1532
1533 i.name = b_entry_name;
1534 i.value = buffer;
1535 i.value_len = size;
1536 error = ext4_xattr_block_find(inode, &i, bs);
1537 if (error)
1538 goto cleanup;
1539
1540 /* Add entry which was removed from the inode into the block */
1541 error = ext4_xattr_block_set(handle, inode, &i, bs);
1542 if (error)
1543 goto cleanup;
1544 kfree(b_entry_name);
1545 kfree(buffer);
1546 b_entry_name = NULL;
1547 buffer = NULL;
1548 brelse(is->iloc.bh);
1549 kfree(is);
1550 kfree(bs);
1551 }
1552 brelse(bh);
1553 up_write(&EXT4_I(inode)->xattr_sem);
1554 return 0;
1555
1556cleanup:
1557 kfree(b_entry_name);
1558 kfree(buffer);
1559 if (is)
1560 brelse(is->iloc.bh);
1561 kfree(is);
1562 kfree(bs);
1563 brelse(bh);
1564 up_write(&EXT4_I(inode)->xattr_sem);
1565 return error;
1566}
1567
1568
1569
1570/*
1571 * ext4_xattr_delete_inode()
1572 *
1573 * Free extended attribute resources associated with this inode. This
1574 * is called immediately before an inode is freed. We have exclusive
1575 * access to the inode.
1576 */
1577void
1578ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1579{
1580 struct buffer_head *bh = NULL;
1581
1582 if (!EXT4_I(inode)->i_file_acl)
1583 goto cleanup;
1584 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1585 if (!bh) {
1586 EXT4_ERROR_INODE(inode, "block %llu read error",
1587 EXT4_I(inode)->i_file_acl);
1588 goto cleanup;
1589 }
1590 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1591 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1592 EXT4_ERROR_INODE(inode, "bad block %llu",
1593 EXT4_I(inode)->i_file_acl);
1594 goto cleanup;
1595 }
1596 ext4_xattr_release_block(handle, inode, bh);
1597 EXT4_I(inode)->i_file_acl = 0;
1598
1599cleanup:
1600 brelse(bh);
1601}
1602
1603/*
1604 * ext4_xattr_cache_insert()
1605 *
1606 * Create a new entry in the extended attribute cache, and insert
1607 * it unless such an entry is already in the cache.
1608 *
1609 * Returns 0, or a negative error number on failure.
1610 */
1611static void
1612ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1613{
1614 struct ext4_xattr_header *header = BHDR(bh);
1615 __u32 hash = le32_to_cpu(header->h_hash);
1616 int reusable = le32_to_cpu(header->h_refcount) <
1617 EXT4_XATTR_REFCOUNT_MAX;
1618 int error;
1619
1620 error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1621 bh->b_blocknr, reusable);
1622 if (error) {
1623 if (error == -EBUSY)
1624 ea_bdebug(bh, "already in cache");
1625 } else
1626 ea_bdebug(bh, "inserting [%x]", (int)hash);
1627}
1628
1629/*
1630 * ext4_xattr_cmp()
1631 *
1632 * Compare two extended attribute blocks for equality.
1633 *
1634 * Returns 0 if the blocks are equal, 1 if they differ, and
1635 * a negative error number on errors.
1636 */
1637static int
1638ext4_xattr_cmp(struct ext4_xattr_header *header1,
1639 struct ext4_xattr_header *header2)
1640{
1641 struct ext4_xattr_entry *entry1, *entry2;
1642
1643 entry1 = ENTRY(header1+1);
1644 entry2 = ENTRY(header2+1);
1645 while (!IS_LAST_ENTRY(entry1)) {
1646 if (IS_LAST_ENTRY(entry2))
1647 return 1;
1648 if (entry1->e_hash != entry2->e_hash ||
1649 entry1->e_name_index != entry2->e_name_index ||
1650 entry1->e_name_len != entry2->e_name_len ||
1651 entry1->e_value_size != entry2->e_value_size ||
1652 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1653 return 1;
1654 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1655 return -EFSCORRUPTED;
1656 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1657 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1658 le32_to_cpu(entry1->e_value_size)))
1659 return 1;
1660
1661 entry1 = EXT4_XATTR_NEXT(entry1);
1662 entry2 = EXT4_XATTR_NEXT(entry2);
1663 }
1664 if (!IS_LAST_ENTRY(entry2))
1665 return 1;
1666 return 0;
1667}
1668
1669/*
1670 * ext4_xattr_cache_find()
1671 *
1672 * Find an identical extended attribute block.
1673 *
1674 * Returns a pointer to the block found, or NULL if such a block was
1675 * not found or an error occurred.
1676 */
1677static struct buffer_head *
1678ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1679 struct mb_cache_entry **pce)
1680{
1681 __u32 hash = le32_to_cpu(header->h_hash);
1682 struct mb_cache_entry *ce;
1683 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1684
1685 if (!header->h_hash)
1686 return NULL; /* never share */
1687 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1688 ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1689 while (ce) {
1690 struct buffer_head *bh;
1691
1692 bh = sb_bread(inode->i_sb, ce->e_block);
1693 if (!bh) {
1694 EXT4_ERROR_INODE(inode, "block %lu read error",
1695 (unsigned long) ce->e_block);
1696 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1697 *pce = ce;
1698 return bh;
1699 }
1700 brelse(bh);
1701 ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1702 }
1703 return NULL;
1704}
1705
1706#define NAME_HASH_SHIFT 5
1707#define VALUE_HASH_SHIFT 16
1708
1709/*
1710 * ext4_xattr_hash_entry()
1711 *
1712 * Compute the hash of an extended attribute.
1713 */
1714static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1715 struct ext4_xattr_entry *entry)
1716{
1717 __u32 hash = 0;
1718 char *name = entry->e_name;
1719 int n;
1720
1721 for (n = 0; n < entry->e_name_len; n++) {
1722 hash = (hash << NAME_HASH_SHIFT) ^
1723 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1724 *name++;
1725 }
1726
1727 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1728 __le32 *value = (__le32 *)((char *)header +
1729 le16_to_cpu(entry->e_value_offs));
1730 for (n = (le32_to_cpu(entry->e_value_size) +
1731 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1732 hash = (hash << VALUE_HASH_SHIFT) ^
1733 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1734 le32_to_cpu(*value++);
1735 }
1736 }
1737 entry->e_hash = cpu_to_le32(hash);
1738}
1739
1740#undef NAME_HASH_SHIFT
1741#undef VALUE_HASH_SHIFT
1742
1743#define BLOCK_HASH_SHIFT 16
1744
1745/*
1746 * ext4_xattr_rehash()
1747 *
1748 * Re-compute the extended attribute hash value after an entry has changed.
1749 */
1750static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1751 struct ext4_xattr_entry *entry)
1752{
1753 struct ext4_xattr_entry *here;
1754 __u32 hash = 0;
1755
1756 ext4_xattr_hash_entry(header, entry);
1757 here = ENTRY(header+1);
1758 while (!IS_LAST_ENTRY(here)) {
1759 if (!here->e_hash) {
1760 /* Block is not shared if an entry's hash value == 0 */
1761 hash = 0;
1762 break;
1763 }
1764 hash = (hash << BLOCK_HASH_SHIFT) ^
1765 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1766 le32_to_cpu(here->e_hash);
1767 here = EXT4_XATTR_NEXT(here);
1768 }
1769 header->h_hash = cpu_to_le32(hash);
1770}
1771
1772#undef BLOCK_HASH_SHIFT
1773
1774#define HASH_BUCKET_BITS 10
1775
1776struct mb_cache *
1777ext4_xattr_create_cache(void)
1778{
1779 return mb_cache_create(HASH_BUCKET_BITS);
1780}
1781
1782void ext4_xattr_destroy_cache(struct mb_cache *cache)
1783{
1784 if (cache)
1785 mb_cache_destroy(cache);
1786}
1787