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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 <linux/rwsem.h>
59#include "ext4_jbd2.h"
60#include "ext4.h"
61#include "xattr.h"
62#include "acl.h"
63
64#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
65#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
66#define BFIRST(bh) ENTRY(BHDR(bh)+1)
67#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
68
69#ifdef EXT4_XATTR_DEBUG
70# define ea_idebug(inode, f...) do { \
71 printk(KERN_DEBUG "inode %s:%lu: ", \
72 inode->i_sb->s_id, inode->i_ino); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76# define ea_bdebug(bh, f...) do { \
77 char b[BDEVNAME_SIZE]; \
78 printk(KERN_DEBUG "block %s:%lu: ", \
79 bdevname(bh->b_bdev, b), \
80 (unsigned long) bh->b_blocknr); \
81 printk(f); \
82 printk("\n"); \
83 } while (0)
84#else
85# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
86# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
87#endif
88
89static void ext4_xattr_cache_insert(struct buffer_head *);
90static struct buffer_head *ext4_xattr_cache_find(struct inode *,
91 struct ext4_xattr_header *,
92 struct mb_cache_entry **);
93static void ext4_xattr_rehash(struct ext4_xattr_header *,
94 struct ext4_xattr_entry *);
95static int ext4_xattr_list(struct dentry *dentry, char *buffer,
96 size_t buffer_size);
97
98static struct mb_cache *ext4_xattr_cache;
99
100static const struct xattr_handler *ext4_xattr_handler_map[] = {
101 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
102#ifdef CONFIG_EXT4_FS_POSIX_ACL
103 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
104 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
105#endif
106 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
107#ifdef CONFIG_EXT4_FS_SECURITY
108 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
109#endif
110};
111
112const struct xattr_handler *ext4_xattr_handlers[] = {
113 &ext4_xattr_user_handler,
114 &ext4_xattr_trusted_handler,
115#ifdef CONFIG_EXT4_FS_POSIX_ACL
116 &ext4_xattr_acl_access_handler,
117 &ext4_xattr_acl_default_handler,
118#endif
119#ifdef CONFIG_EXT4_FS_SECURITY
120 &ext4_xattr_security_handler,
121#endif
122 NULL
123};
124
125static __le32 ext4_xattr_block_csum(struct inode *inode,
126 sector_t block_nr,
127 struct ext4_xattr_header *hdr)
128{
129 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
130 __u32 csum, old;
131
132 old = hdr->h_checksum;
133 hdr->h_checksum = 0;
134 block_nr = cpu_to_le64(block_nr);
135 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&block_nr,
136 sizeof(block_nr));
137 csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
138 EXT4_BLOCK_SIZE(inode->i_sb));
139
140 hdr->h_checksum = old;
141 return cpu_to_le32(csum);
142}
143
144static int ext4_xattr_block_csum_verify(struct inode *inode,
145 sector_t block_nr,
146 struct ext4_xattr_header *hdr)
147{
148 if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
149 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
150 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
151 return 0;
152 return 1;
153}
154
155static void ext4_xattr_block_csum_set(struct inode *inode,
156 sector_t block_nr,
157 struct ext4_xattr_header *hdr)
158{
159 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
160 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
161 return;
162
163 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
164}
165
166static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
167 struct inode *inode,
168 struct buffer_head *bh)
169{
170 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
171 return ext4_handle_dirty_metadata(handle, inode, bh);
172}
173
174static inline const struct xattr_handler *
175ext4_xattr_handler(int name_index)
176{
177 const struct xattr_handler *handler = NULL;
178
179 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
180 handler = ext4_xattr_handler_map[name_index];
181 return handler;
182}
183
184/*
185 * Inode operation listxattr()
186 *
187 * dentry->d_inode->i_mutex: don't care
188 */
189ssize_t
190ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
191{
192 return ext4_xattr_list(dentry, buffer, size);
193}
194
195static int
196ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
197{
198 while (!IS_LAST_ENTRY(entry)) {
199 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
200 if ((void *)next >= end)
201 return -EIO;
202 entry = next;
203 }
204 return 0;
205}
206
207static inline int
208ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
209{
210 int error;
211
212 if (buffer_verified(bh))
213 return 0;
214
215 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
216 BHDR(bh)->h_blocks != cpu_to_le32(1))
217 return -EIO;
218 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
219 return -EIO;
220 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
221 if (!error)
222 set_buffer_verified(bh);
223 return error;
224}
225
226static inline int
227ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
228{
229 size_t value_size = le32_to_cpu(entry->e_value_size);
230
231 if (entry->e_value_block != 0 || value_size > size ||
232 le16_to_cpu(entry->e_value_offs) + value_size > size)
233 return -EIO;
234 return 0;
235}
236
237static int
238ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
239 const char *name, size_t size, int sorted)
240{
241 struct ext4_xattr_entry *entry;
242 size_t name_len;
243 int cmp = 1;
244
245 if (name == NULL)
246 return -EINVAL;
247 name_len = strlen(name);
248 entry = *pentry;
249 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
250 cmp = name_index - entry->e_name_index;
251 if (!cmp)
252 cmp = name_len - entry->e_name_len;
253 if (!cmp)
254 cmp = memcmp(name, entry->e_name, name_len);
255 if (cmp <= 0 && (sorted || cmp == 0))
256 break;
257 }
258 *pentry = entry;
259 if (!cmp && ext4_xattr_check_entry(entry, size))
260 return -EIO;
261 return cmp ? -ENODATA : 0;
262}
263
264static int
265ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
266 void *buffer, size_t buffer_size)
267{
268 struct buffer_head *bh = NULL;
269 struct ext4_xattr_entry *entry;
270 size_t size;
271 int error;
272
273 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
274 name_index, name, buffer, (long)buffer_size);
275
276 error = -ENODATA;
277 if (!EXT4_I(inode)->i_file_acl)
278 goto cleanup;
279 ea_idebug(inode, "reading block %llu",
280 (unsigned long long)EXT4_I(inode)->i_file_acl);
281 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
282 if (!bh)
283 goto cleanup;
284 ea_bdebug(bh, "b_count=%d, refcount=%d",
285 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
286 if (ext4_xattr_check_block(inode, bh)) {
287bad_block:
288 EXT4_ERROR_INODE(inode, "bad block %llu",
289 EXT4_I(inode)->i_file_acl);
290 error = -EIO;
291 goto cleanup;
292 }
293 ext4_xattr_cache_insert(bh);
294 entry = BFIRST(bh);
295 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
296 if (error == -EIO)
297 goto bad_block;
298 if (error)
299 goto cleanup;
300 size = le32_to_cpu(entry->e_value_size);
301 if (buffer) {
302 error = -ERANGE;
303 if (size > buffer_size)
304 goto cleanup;
305 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
306 size);
307 }
308 error = size;
309
310cleanup:
311 brelse(bh);
312 return error;
313}
314
315static int
316ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
317 void *buffer, size_t buffer_size)
318{
319 struct ext4_xattr_ibody_header *header;
320 struct ext4_xattr_entry *entry;
321 struct ext4_inode *raw_inode;
322 struct ext4_iloc iloc;
323 size_t size;
324 void *end;
325 int error;
326
327 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
328 return -ENODATA;
329 error = ext4_get_inode_loc(inode, &iloc);
330 if (error)
331 return error;
332 raw_inode = ext4_raw_inode(&iloc);
333 header = IHDR(inode, raw_inode);
334 entry = IFIRST(header);
335 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
336 error = ext4_xattr_check_names(entry, end);
337 if (error)
338 goto cleanup;
339 error = ext4_xattr_find_entry(&entry, name_index, name,
340 end - (void *)entry, 0);
341 if (error)
342 goto cleanup;
343 size = le32_to_cpu(entry->e_value_size);
344 if (buffer) {
345 error = -ERANGE;
346 if (size > buffer_size)
347 goto cleanup;
348 memcpy(buffer, (void *)IFIRST(header) +
349 le16_to_cpu(entry->e_value_offs), size);
350 }
351 error = size;
352
353cleanup:
354 brelse(iloc.bh);
355 return error;
356}
357
358/*
359 * ext4_xattr_get()
360 *
361 * Copy an extended attribute into the buffer
362 * provided, or compute the buffer size required.
363 * Buffer is NULL to compute the size of the buffer required.
364 *
365 * Returns a negative error number on failure, or the number of bytes
366 * used / required on success.
367 */
368int
369ext4_xattr_get(struct inode *inode, int name_index, const char *name,
370 void *buffer, size_t buffer_size)
371{
372 int error;
373
374 down_read(&EXT4_I(inode)->xattr_sem);
375 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
376 buffer_size);
377 if (error == -ENODATA)
378 error = ext4_xattr_block_get(inode, name_index, name, buffer,
379 buffer_size);
380 up_read(&EXT4_I(inode)->xattr_sem);
381 return error;
382}
383
384static int
385ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
386 char *buffer, size_t buffer_size)
387{
388 size_t rest = buffer_size;
389
390 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
391 const struct xattr_handler *handler =
392 ext4_xattr_handler(entry->e_name_index);
393
394 if (handler) {
395 size_t size = handler->list(dentry, buffer, rest,
396 entry->e_name,
397 entry->e_name_len,
398 handler->flags);
399 if (buffer) {
400 if (size > rest)
401 return -ERANGE;
402 buffer += size;
403 }
404 rest -= size;
405 }
406 }
407 return buffer_size - rest;
408}
409
410static int
411ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
412{
413 struct inode *inode = dentry->d_inode;
414 struct buffer_head *bh = NULL;
415 int error;
416
417 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
418 buffer, (long)buffer_size);
419
420 error = 0;
421 if (!EXT4_I(inode)->i_file_acl)
422 goto cleanup;
423 ea_idebug(inode, "reading block %llu",
424 (unsigned long long)EXT4_I(inode)->i_file_acl);
425 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
426 error = -EIO;
427 if (!bh)
428 goto cleanup;
429 ea_bdebug(bh, "b_count=%d, refcount=%d",
430 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
431 if (ext4_xattr_check_block(inode, bh)) {
432 EXT4_ERROR_INODE(inode, "bad block %llu",
433 EXT4_I(inode)->i_file_acl);
434 error = -EIO;
435 goto cleanup;
436 }
437 ext4_xattr_cache_insert(bh);
438 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
439
440cleanup:
441 brelse(bh);
442
443 return error;
444}
445
446static int
447ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
448{
449 struct inode *inode = dentry->d_inode;
450 struct ext4_xattr_ibody_header *header;
451 struct ext4_inode *raw_inode;
452 struct ext4_iloc iloc;
453 void *end;
454 int error;
455
456 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
457 return 0;
458 error = ext4_get_inode_loc(inode, &iloc);
459 if (error)
460 return error;
461 raw_inode = ext4_raw_inode(&iloc);
462 header = IHDR(inode, raw_inode);
463 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
464 error = ext4_xattr_check_names(IFIRST(header), end);
465 if (error)
466 goto cleanup;
467 error = ext4_xattr_list_entries(dentry, IFIRST(header),
468 buffer, buffer_size);
469
470cleanup:
471 brelse(iloc.bh);
472 return error;
473}
474
475/*
476 * ext4_xattr_list()
477 *
478 * Copy a list of attribute names into the buffer
479 * provided, or compute the buffer size required.
480 * Buffer is NULL to compute the size of the buffer required.
481 *
482 * Returns a negative error number on failure, or the number of bytes
483 * used / required on success.
484 */
485static int
486ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
487{
488 int ret, ret2;
489
490 down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
491 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
492 if (ret < 0)
493 goto errout;
494 if (buffer) {
495 buffer += ret;
496 buffer_size -= ret;
497 }
498 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
499 if (ret < 0)
500 goto errout;
501 ret += ret2;
502errout:
503 up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
504 return ret;
505}
506
507/*
508 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
509 * not set, set it.
510 */
511static void ext4_xattr_update_super_block(handle_t *handle,
512 struct super_block *sb)
513{
514 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
515 return;
516
517 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
518 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
519 ext4_handle_dirty_super(handle, sb);
520 }
521}
522
523/*
524 * Release the xattr block BH: If the reference count is > 1, decrement
525 * it; otherwise free the block.
526 */
527static void
528ext4_xattr_release_block(handle_t *handle, struct inode *inode,
529 struct buffer_head *bh)
530{
531 struct mb_cache_entry *ce = NULL;
532 int error = 0;
533
534 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
535 error = ext4_journal_get_write_access(handle, bh);
536 if (error)
537 goto out;
538
539 lock_buffer(bh);
540 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
541 ea_bdebug(bh, "refcount now=0; freeing");
542 if (ce)
543 mb_cache_entry_free(ce);
544 get_bh(bh);
545 ext4_free_blocks(handle, inode, bh, 0, 1,
546 EXT4_FREE_BLOCKS_METADATA |
547 EXT4_FREE_BLOCKS_FORGET);
548 unlock_buffer(bh);
549 } else {
550 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
551 if (ce)
552 mb_cache_entry_release(ce);
553 unlock_buffer(bh);
554 error = ext4_handle_dirty_xattr_block(handle, inode, bh);
555 if (IS_SYNC(inode))
556 ext4_handle_sync(handle);
557 dquot_free_block(inode, 1);
558 ea_bdebug(bh, "refcount now=%d; releasing",
559 le32_to_cpu(BHDR(bh)->h_refcount));
560 }
561out:
562 ext4_std_error(inode->i_sb, error);
563 return;
564}
565
566/*
567 * Find the available free space for EAs. This also returns the total number of
568 * bytes used by EA entries.
569 */
570static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
571 size_t *min_offs, void *base, int *total)
572{
573 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
574 *total += EXT4_XATTR_LEN(last->e_name_len);
575 if (!last->e_value_block && last->e_value_size) {
576 size_t offs = le16_to_cpu(last->e_value_offs);
577 if (offs < *min_offs)
578 *min_offs = offs;
579 }
580 }
581 return (*min_offs - ((void *)last - base) - sizeof(__u32));
582}
583
584struct ext4_xattr_info {
585 int name_index;
586 const char *name;
587 const void *value;
588 size_t value_len;
589};
590
591struct ext4_xattr_search {
592 struct ext4_xattr_entry *first;
593 void *base;
594 void *end;
595 struct ext4_xattr_entry *here;
596 int not_found;
597};
598
599static int
600ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
601{
602 struct ext4_xattr_entry *last;
603 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
604
605 /* Compute min_offs and last. */
606 last = s->first;
607 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
608 if (!last->e_value_block && last->e_value_size) {
609 size_t offs = le16_to_cpu(last->e_value_offs);
610 if (offs < min_offs)
611 min_offs = offs;
612 }
613 }
614 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
615 if (!s->not_found) {
616 if (!s->here->e_value_block && s->here->e_value_size) {
617 size_t size = le32_to_cpu(s->here->e_value_size);
618 free += EXT4_XATTR_SIZE(size);
619 }
620 free += EXT4_XATTR_LEN(name_len);
621 }
622 if (i->value) {
623 if (free < EXT4_XATTR_SIZE(i->value_len) ||
624 free < EXT4_XATTR_LEN(name_len) +
625 EXT4_XATTR_SIZE(i->value_len))
626 return -ENOSPC;
627 }
628
629 if (i->value && s->not_found) {
630 /* Insert the new name. */
631 size_t size = EXT4_XATTR_LEN(name_len);
632 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
633 memmove((void *)s->here + size, s->here, rest);
634 memset(s->here, 0, size);
635 s->here->e_name_index = i->name_index;
636 s->here->e_name_len = name_len;
637 memcpy(s->here->e_name, i->name, name_len);
638 } else {
639 if (!s->here->e_value_block && s->here->e_value_size) {
640 void *first_val = s->base + min_offs;
641 size_t offs = le16_to_cpu(s->here->e_value_offs);
642 void *val = s->base + offs;
643 size_t size = EXT4_XATTR_SIZE(
644 le32_to_cpu(s->here->e_value_size));
645
646 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
647 /* The old and the new value have the same
648 size. Just replace. */
649 s->here->e_value_size =
650 cpu_to_le32(i->value_len);
651 memset(val + size - EXT4_XATTR_PAD, 0,
652 EXT4_XATTR_PAD); /* Clear pad bytes. */
653 memcpy(val, i->value, i->value_len);
654 return 0;
655 }
656
657 /* Remove the old value. */
658 memmove(first_val + size, first_val, val - first_val);
659 memset(first_val, 0, size);
660 s->here->e_value_size = 0;
661 s->here->e_value_offs = 0;
662 min_offs += size;
663
664 /* Adjust all value offsets. */
665 last = s->first;
666 while (!IS_LAST_ENTRY(last)) {
667 size_t o = le16_to_cpu(last->e_value_offs);
668 if (!last->e_value_block &&
669 last->e_value_size && o < offs)
670 last->e_value_offs =
671 cpu_to_le16(o + size);
672 last = EXT4_XATTR_NEXT(last);
673 }
674 }
675 if (!i->value) {
676 /* Remove the old name. */
677 size_t size = EXT4_XATTR_LEN(name_len);
678 last = ENTRY((void *)last - size);
679 memmove(s->here, (void *)s->here + size,
680 (void *)last - (void *)s->here + sizeof(__u32));
681 memset(last, 0, size);
682 }
683 }
684
685 if (i->value) {
686 /* Insert the new value. */
687 s->here->e_value_size = cpu_to_le32(i->value_len);
688 if (i->value_len) {
689 size_t size = EXT4_XATTR_SIZE(i->value_len);
690 void *val = s->base + min_offs - size;
691 s->here->e_value_offs = cpu_to_le16(min_offs - size);
692 memset(val + size - EXT4_XATTR_PAD, 0,
693 EXT4_XATTR_PAD); /* Clear the pad bytes. */
694 memcpy(val, i->value, i->value_len);
695 }
696 }
697 return 0;
698}
699
700struct ext4_xattr_block_find {
701 struct ext4_xattr_search s;
702 struct buffer_head *bh;
703};
704
705static int
706ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
707 struct ext4_xattr_block_find *bs)
708{
709 struct super_block *sb = inode->i_sb;
710 int error;
711
712 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
713 i->name_index, i->name, i->value, (long)i->value_len);
714
715 if (EXT4_I(inode)->i_file_acl) {
716 /* The inode already has an extended attribute block. */
717 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
718 error = -EIO;
719 if (!bs->bh)
720 goto cleanup;
721 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
722 atomic_read(&(bs->bh->b_count)),
723 le32_to_cpu(BHDR(bs->bh)->h_refcount));
724 if (ext4_xattr_check_block(inode, bs->bh)) {
725 EXT4_ERROR_INODE(inode, "bad block %llu",
726 EXT4_I(inode)->i_file_acl);
727 error = -EIO;
728 goto cleanup;
729 }
730 /* Find the named attribute. */
731 bs->s.base = BHDR(bs->bh);
732 bs->s.first = BFIRST(bs->bh);
733 bs->s.end = bs->bh->b_data + bs->bh->b_size;
734 bs->s.here = bs->s.first;
735 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
736 i->name, bs->bh->b_size, 1);
737 if (error && error != -ENODATA)
738 goto cleanup;
739 bs->s.not_found = error;
740 }
741 error = 0;
742
743cleanup:
744 return error;
745}
746
747static int
748ext4_xattr_block_set(handle_t *handle, struct inode *inode,
749 struct ext4_xattr_info *i,
750 struct ext4_xattr_block_find *bs)
751{
752 struct super_block *sb = inode->i_sb;
753 struct buffer_head *new_bh = NULL;
754 struct ext4_xattr_search *s = &bs->s;
755 struct mb_cache_entry *ce = NULL;
756 int error = 0;
757
758#define header(x) ((struct ext4_xattr_header *)(x))
759
760 if (i->value && i->value_len > sb->s_blocksize)
761 return -ENOSPC;
762 if (s->base) {
763 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
764 bs->bh->b_blocknr);
765 error = ext4_journal_get_write_access(handle, bs->bh);
766 if (error)
767 goto cleanup;
768 lock_buffer(bs->bh);
769
770 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
771 if (ce) {
772 mb_cache_entry_free(ce);
773 ce = NULL;
774 }
775 ea_bdebug(bs->bh, "modifying in-place");
776 error = ext4_xattr_set_entry(i, s);
777 if (!error) {
778 if (!IS_LAST_ENTRY(s->first))
779 ext4_xattr_rehash(header(s->base),
780 s->here);
781 ext4_xattr_cache_insert(bs->bh);
782 }
783 unlock_buffer(bs->bh);
784 if (error == -EIO)
785 goto bad_block;
786 if (!error)
787 error = ext4_handle_dirty_xattr_block(handle,
788 inode,
789 bs->bh);
790 if (error)
791 goto cleanup;
792 goto inserted;
793 } else {
794 int offset = (char *)s->here - bs->bh->b_data;
795
796 unlock_buffer(bs->bh);
797 ext4_handle_release_buffer(handle, bs->bh);
798 if (ce) {
799 mb_cache_entry_release(ce);
800 ce = NULL;
801 }
802 ea_bdebug(bs->bh, "cloning");
803 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
804 error = -ENOMEM;
805 if (s->base == NULL)
806 goto cleanup;
807 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
808 s->first = ENTRY(header(s->base)+1);
809 header(s->base)->h_refcount = cpu_to_le32(1);
810 s->here = ENTRY(s->base + offset);
811 s->end = s->base + bs->bh->b_size;
812 }
813 } else {
814 /* Allocate a buffer where we construct the new block. */
815 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
816 /* assert(header == s->base) */
817 error = -ENOMEM;
818 if (s->base == NULL)
819 goto cleanup;
820 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
821 header(s->base)->h_blocks = cpu_to_le32(1);
822 header(s->base)->h_refcount = cpu_to_le32(1);
823 s->first = ENTRY(header(s->base)+1);
824 s->here = ENTRY(header(s->base)+1);
825 s->end = s->base + sb->s_blocksize;
826 }
827
828 error = ext4_xattr_set_entry(i, s);
829 if (error == -EIO)
830 goto bad_block;
831 if (error)
832 goto cleanup;
833 if (!IS_LAST_ENTRY(s->first))
834 ext4_xattr_rehash(header(s->base), s->here);
835
836inserted:
837 if (!IS_LAST_ENTRY(s->first)) {
838 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
839 if (new_bh) {
840 /* We found an identical block in the cache. */
841 if (new_bh == bs->bh)
842 ea_bdebug(new_bh, "keeping");
843 else {
844 /* The old block is released after updating
845 the inode. */
846 error = dquot_alloc_block(inode, 1);
847 if (error)
848 goto cleanup;
849 error = ext4_journal_get_write_access(handle,
850 new_bh);
851 if (error)
852 goto cleanup_dquot;
853 lock_buffer(new_bh);
854 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
855 ea_bdebug(new_bh, "reusing; refcount now=%d",
856 le32_to_cpu(BHDR(new_bh)->h_refcount));
857 unlock_buffer(new_bh);
858 error = ext4_handle_dirty_xattr_block(handle,
859 inode,
860 new_bh);
861 if (error)
862 goto cleanup_dquot;
863 }
864 mb_cache_entry_release(ce);
865 ce = NULL;
866 } else if (bs->bh && s->base == bs->bh->b_data) {
867 /* We were modifying this block in-place. */
868 ea_bdebug(bs->bh, "keeping this block");
869 new_bh = bs->bh;
870 get_bh(new_bh);
871 } else {
872 /* We need to allocate a new block */
873 ext4_fsblk_t goal, block;
874
875 goal = ext4_group_first_block_no(sb,
876 EXT4_I(inode)->i_block_group);
877
878 /* non-extent files can't have physical blocks past 2^32 */
879 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
880 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
881
882 /*
883 * take i_data_sem because we will test
884 * i_delalloc_reserved_flag in ext4_mb_new_blocks
885 */
886 down_read((&EXT4_I(inode)->i_data_sem));
887 block = ext4_new_meta_blocks(handle, inode, goal, 0,
888 NULL, &error);
889 up_read((&EXT4_I(inode)->i_data_sem));
890 if (error)
891 goto cleanup;
892
893 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
894 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
895
896 ea_idebug(inode, "creating block %llu",
897 (unsigned long long)block);
898
899 new_bh = sb_getblk(sb, block);
900 if (!new_bh) {
901getblk_failed:
902 ext4_free_blocks(handle, inode, NULL, block, 1,
903 EXT4_FREE_BLOCKS_METADATA);
904 error = -EIO;
905 goto cleanup;
906 }
907 lock_buffer(new_bh);
908 error = ext4_journal_get_create_access(handle, new_bh);
909 if (error) {
910 unlock_buffer(new_bh);
911 goto getblk_failed;
912 }
913 memcpy(new_bh->b_data, s->base, new_bh->b_size);
914 set_buffer_uptodate(new_bh);
915 unlock_buffer(new_bh);
916 ext4_xattr_cache_insert(new_bh);
917 error = ext4_handle_dirty_xattr_block(handle,
918 inode, new_bh);
919 if (error)
920 goto cleanup;
921 }
922 }
923
924 /* Update the inode. */
925 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
926
927 /* Drop the previous xattr block. */
928 if (bs->bh && bs->bh != new_bh)
929 ext4_xattr_release_block(handle, inode, bs->bh);
930 error = 0;
931
932cleanup:
933 if (ce)
934 mb_cache_entry_release(ce);
935 brelse(new_bh);
936 if (!(bs->bh && s->base == bs->bh->b_data))
937 kfree(s->base);
938
939 return error;
940
941cleanup_dquot:
942 dquot_free_block(inode, 1);
943 goto cleanup;
944
945bad_block:
946 EXT4_ERROR_INODE(inode, "bad block %llu",
947 EXT4_I(inode)->i_file_acl);
948 goto cleanup;
949
950#undef header
951}
952
953struct ext4_xattr_ibody_find {
954 struct ext4_xattr_search s;
955 struct ext4_iloc iloc;
956};
957
958static int
959ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
960 struct ext4_xattr_ibody_find *is)
961{
962 struct ext4_xattr_ibody_header *header;
963 struct ext4_inode *raw_inode;
964 int error;
965
966 if (EXT4_I(inode)->i_extra_isize == 0)
967 return 0;
968 raw_inode = ext4_raw_inode(&is->iloc);
969 header = IHDR(inode, raw_inode);
970 is->s.base = is->s.first = IFIRST(header);
971 is->s.here = is->s.first;
972 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
973 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
974 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
975 if (error)
976 return error;
977 /* Find the named attribute. */
978 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
979 i->name, is->s.end -
980 (void *)is->s.base, 0);
981 if (error && error != -ENODATA)
982 return error;
983 is->s.not_found = error;
984 }
985 return 0;
986}
987
988static int
989ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
990 struct ext4_xattr_info *i,
991 struct ext4_xattr_ibody_find *is)
992{
993 struct ext4_xattr_ibody_header *header;
994 struct ext4_xattr_search *s = &is->s;
995 int error;
996
997 if (EXT4_I(inode)->i_extra_isize == 0)
998 return -ENOSPC;
999 error = ext4_xattr_set_entry(i, s);
1000 if (error)
1001 return error;
1002 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1003 if (!IS_LAST_ENTRY(s->first)) {
1004 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1005 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1006 } else {
1007 header->h_magic = cpu_to_le32(0);
1008 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1009 }
1010 return 0;
1011}
1012
1013/*
1014 * ext4_xattr_set_handle()
1015 *
1016 * Create, replace or remove an extended attribute for this inode. Value
1017 * is NULL to remove an existing extended attribute, and non-NULL to
1018 * either replace an existing extended attribute, or create a new extended
1019 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1020 * specify that an extended attribute must exist and must not exist
1021 * previous to the call, respectively.
1022 *
1023 * Returns 0, or a negative error number on failure.
1024 */
1025int
1026ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1027 const char *name, const void *value, size_t value_len,
1028 int flags)
1029{
1030 struct ext4_xattr_info i = {
1031 .name_index = name_index,
1032 .name = name,
1033 .value = value,
1034 .value_len = value_len,
1035
1036 };
1037 struct ext4_xattr_ibody_find is = {
1038 .s = { .not_found = -ENODATA, },
1039 };
1040 struct ext4_xattr_block_find bs = {
1041 .s = { .not_found = -ENODATA, },
1042 };
1043 unsigned long no_expand;
1044 int error;
1045
1046 if (!name)
1047 return -EINVAL;
1048 if (strlen(name) > 255)
1049 return -ERANGE;
1050 down_write(&EXT4_I(inode)->xattr_sem);
1051 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1052 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1053
1054 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1055 if (error)
1056 goto cleanup;
1057
1058 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1059 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1060 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1061 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1062 }
1063
1064 error = ext4_xattr_ibody_find(inode, &i, &is);
1065 if (error)
1066 goto cleanup;
1067 if (is.s.not_found)
1068 error = ext4_xattr_block_find(inode, &i, &bs);
1069 if (error)
1070 goto cleanup;
1071 if (is.s.not_found && bs.s.not_found) {
1072 error = -ENODATA;
1073 if (flags & XATTR_REPLACE)
1074 goto cleanup;
1075 error = 0;
1076 if (!value)
1077 goto cleanup;
1078 } else {
1079 error = -EEXIST;
1080 if (flags & XATTR_CREATE)
1081 goto cleanup;
1082 }
1083 if (!value) {
1084 if (!is.s.not_found)
1085 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1086 else if (!bs.s.not_found)
1087 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1088 } else {
1089 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1090 if (!error && !bs.s.not_found) {
1091 i.value = NULL;
1092 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1093 } else if (error == -ENOSPC) {
1094 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1095 error = ext4_xattr_block_find(inode, &i, &bs);
1096 if (error)
1097 goto cleanup;
1098 }
1099 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1100 if (error)
1101 goto cleanup;
1102 if (!is.s.not_found) {
1103 i.value = NULL;
1104 error = ext4_xattr_ibody_set(handle, inode, &i,
1105 &is);
1106 }
1107 }
1108 }
1109 if (!error) {
1110 ext4_xattr_update_super_block(handle, inode->i_sb);
1111 inode->i_ctime = ext4_current_time(inode);
1112 if (!value)
1113 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1114 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1115 /*
1116 * The bh is consumed by ext4_mark_iloc_dirty, even with
1117 * error != 0.
1118 */
1119 is.iloc.bh = NULL;
1120 if (IS_SYNC(inode))
1121 ext4_handle_sync(handle);
1122 }
1123
1124cleanup:
1125 brelse(is.iloc.bh);
1126 brelse(bs.bh);
1127 if (no_expand == 0)
1128 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1129 up_write(&EXT4_I(inode)->xattr_sem);
1130 return error;
1131}
1132
1133/*
1134 * ext4_xattr_set()
1135 *
1136 * Like ext4_xattr_set_handle, but start from an inode. This extended
1137 * attribute modification is a filesystem transaction by itself.
1138 *
1139 * Returns 0, or a negative error number on failure.
1140 */
1141int
1142ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1143 const void *value, size_t value_len, int flags)
1144{
1145 handle_t *handle;
1146 int error, retries = 0;
1147
1148retry:
1149 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1150 if (IS_ERR(handle)) {
1151 error = PTR_ERR(handle);
1152 } else {
1153 int error2;
1154
1155 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1156 value, value_len, flags);
1157 error2 = ext4_journal_stop(handle);
1158 if (error == -ENOSPC &&
1159 ext4_should_retry_alloc(inode->i_sb, &retries))
1160 goto retry;
1161 if (error == 0)
1162 error = error2;
1163 }
1164
1165 return error;
1166}
1167
1168/*
1169 * Shift the EA entries in the inode to create space for the increased
1170 * i_extra_isize.
1171 */
1172static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1173 int value_offs_shift, void *to,
1174 void *from, size_t n, int blocksize)
1175{
1176 struct ext4_xattr_entry *last = entry;
1177 int new_offs;
1178
1179 /* Adjust the value offsets of the entries */
1180 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1181 if (!last->e_value_block && last->e_value_size) {
1182 new_offs = le16_to_cpu(last->e_value_offs) +
1183 value_offs_shift;
1184 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1185 > blocksize);
1186 last->e_value_offs = cpu_to_le16(new_offs);
1187 }
1188 }
1189 /* Shift the entries by n bytes */
1190 memmove(to, from, n);
1191}
1192
1193/*
1194 * Expand an inode by new_extra_isize bytes when EAs are present.
1195 * Returns 0 on success or negative error number on failure.
1196 */
1197int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1198 struct ext4_inode *raw_inode, handle_t *handle)
1199{
1200 struct ext4_xattr_ibody_header *header;
1201 struct ext4_xattr_entry *entry, *last, *first;
1202 struct buffer_head *bh = NULL;
1203 struct ext4_xattr_ibody_find *is = NULL;
1204 struct ext4_xattr_block_find *bs = NULL;
1205 char *buffer = NULL, *b_entry_name = NULL;
1206 size_t min_offs, free;
1207 int total_ino, total_blk;
1208 void *base, *start, *end;
1209 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1210 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1211
1212 down_write(&EXT4_I(inode)->xattr_sem);
1213retry:
1214 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1215 up_write(&EXT4_I(inode)->xattr_sem);
1216 return 0;
1217 }
1218
1219 header = IHDR(inode, raw_inode);
1220 entry = IFIRST(header);
1221
1222 /*
1223 * Check if enough free space is available in the inode to shift the
1224 * entries ahead by new_extra_isize.
1225 */
1226
1227 base = start = entry;
1228 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1229 min_offs = end - base;
1230 last = entry;
1231 total_ino = sizeof(struct ext4_xattr_ibody_header);
1232
1233 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1234 if (free >= new_extra_isize) {
1235 entry = IFIRST(header);
1236 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1237 - new_extra_isize, (void *)raw_inode +
1238 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1239 (void *)header, total_ino,
1240 inode->i_sb->s_blocksize);
1241 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1242 error = 0;
1243 goto cleanup;
1244 }
1245
1246 /*
1247 * Enough free space isn't available in the inode, check if
1248 * EA block can hold new_extra_isize bytes.
1249 */
1250 if (EXT4_I(inode)->i_file_acl) {
1251 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1252 error = -EIO;
1253 if (!bh)
1254 goto cleanup;
1255 if (ext4_xattr_check_block(inode, bh)) {
1256 EXT4_ERROR_INODE(inode, "bad block %llu",
1257 EXT4_I(inode)->i_file_acl);
1258 error = -EIO;
1259 goto cleanup;
1260 }
1261 base = BHDR(bh);
1262 first = BFIRST(bh);
1263 end = bh->b_data + bh->b_size;
1264 min_offs = end - base;
1265 free = ext4_xattr_free_space(first, &min_offs, base,
1266 &total_blk);
1267 if (free < new_extra_isize) {
1268 if (!tried_min_extra_isize && s_min_extra_isize) {
1269 tried_min_extra_isize++;
1270 new_extra_isize = s_min_extra_isize;
1271 brelse(bh);
1272 goto retry;
1273 }
1274 error = -1;
1275 goto cleanup;
1276 }
1277 } else {
1278 free = inode->i_sb->s_blocksize;
1279 }
1280
1281 while (new_extra_isize > 0) {
1282 size_t offs, size, entry_size;
1283 struct ext4_xattr_entry *small_entry = NULL;
1284 struct ext4_xattr_info i = {
1285 .value = NULL,
1286 .value_len = 0,
1287 };
1288 unsigned int total_size; /* EA entry size + value size */
1289 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1290 unsigned int min_total_size = ~0U;
1291
1292 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1293 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1294 if (!is || !bs) {
1295 error = -ENOMEM;
1296 goto cleanup;
1297 }
1298
1299 is->s.not_found = -ENODATA;
1300 bs->s.not_found = -ENODATA;
1301 is->iloc.bh = NULL;
1302 bs->bh = NULL;
1303
1304 last = IFIRST(header);
1305 /* Find the entry best suited to be pushed into EA block */
1306 entry = NULL;
1307 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1308 total_size =
1309 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1310 EXT4_XATTR_LEN(last->e_name_len);
1311 if (total_size <= free && total_size < min_total_size) {
1312 if (total_size < new_extra_isize) {
1313 small_entry = last;
1314 } else {
1315 entry = last;
1316 min_total_size = total_size;
1317 }
1318 }
1319 }
1320
1321 if (entry == NULL) {
1322 if (small_entry) {
1323 entry = small_entry;
1324 } else {
1325 if (!tried_min_extra_isize &&
1326 s_min_extra_isize) {
1327 tried_min_extra_isize++;
1328 new_extra_isize = s_min_extra_isize;
1329 goto retry;
1330 }
1331 error = -1;
1332 goto cleanup;
1333 }
1334 }
1335 offs = le16_to_cpu(entry->e_value_offs);
1336 size = le32_to_cpu(entry->e_value_size);
1337 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1338 i.name_index = entry->e_name_index,
1339 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1340 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1341 if (!buffer || !b_entry_name) {
1342 error = -ENOMEM;
1343 goto cleanup;
1344 }
1345 /* Save the entry name and the entry value */
1346 memcpy(buffer, (void *)IFIRST(header) + offs,
1347 EXT4_XATTR_SIZE(size));
1348 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1349 b_entry_name[entry->e_name_len] = '\0';
1350 i.name = b_entry_name;
1351
1352 error = ext4_get_inode_loc(inode, &is->iloc);
1353 if (error)
1354 goto cleanup;
1355
1356 error = ext4_xattr_ibody_find(inode, &i, is);
1357 if (error)
1358 goto cleanup;
1359
1360 /* Remove the chosen entry from the inode */
1361 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1362 if (error)
1363 goto cleanup;
1364
1365 entry = IFIRST(header);
1366 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1367 shift_bytes = new_extra_isize;
1368 else
1369 shift_bytes = entry_size + size;
1370 /* Adjust the offsets and shift the remaining entries ahead */
1371 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1372 shift_bytes, (void *)raw_inode +
1373 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1374 (void *)header, total_ino - entry_size,
1375 inode->i_sb->s_blocksize);
1376
1377 extra_isize += shift_bytes;
1378 new_extra_isize -= shift_bytes;
1379 EXT4_I(inode)->i_extra_isize = extra_isize;
1380
1381 i.name = b_entry_name;
1382 i.value = buffer;
1383 i.value_len = size;
1384 error = ext4_xattr_block_find(inode, &i, bs);
1385 if (error)
1386 goto cleanup;
1387
1388 /* Add entry which was removed from the inode into the block */
1389 error = ext4_xattr_block_set(handle, inode, &i, bs);
1390 if (error)
1391 goto cleanup;
1392 kfree(b_entry_name);
1393 kfree(buffer);
1394 b_entry_name = NULL;
1395 buffer = NULL;
1396 brelse(is->iloc.bh);
1397 kfree(is);
1398 kfree(bs);
1399 }
1400 brelse(bh);
1401 up_write(&EXT4_I(inode)->xattr_sem);
1402 return 0;
1403
1404cleanup:
1405 kfree(b_entry_name);
1406 kfree(buffer);
1407 if (is)
1408 brelse(is->iloc.bh);
1409 kfree(is);
1410 kfree(bs);
1411 brelse(bh);
1412 up_write(&EXT4_I(inode)->xattr_sem);
1413 return error;
1414}
1415
1416
1417
1418/*
1419 * ext4_xattr_delete_inode()
1420 *
1421 * Free extended attribute resources associated with this inode. This
1422 * is called immediately before an inode is freed. We have exclusive
1423 * access to the inode.
1424 */
1425void
1426ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1427{
1428 struct buffer_head *bh = NULL;
1429
1430 if (!EXT4_I(inode)->i_file_acl)
1431 goto cleanup;
1432 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1433 if (!bh) {
1434 EXT4_ERROR_INODE(inode, "block %llu read error",
1435 EXT4_I(inode)->i_file_acl);
1436 goto cleanup;
1437 }
1438 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1439 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1440 EXT4_ERROR_INODE(inode, "bad block %llu",
1441 EXT4_I(inode)->i_file_acl);
1442 goto cleanup;
1443 }
1444 ext4_xattr_release_block(handle, inode, bh);
1445 EXT4_I(inode)->i_file_acl = 0;
1446
1447cleanup:
1448 brelse(bh);
1449}
1450
1451/*
1452 * ext4_xattr_put_super()
1453 *
1454 * This is called when a file system is unmounted.
1455 */
1456void
1457ext4_xattr_put_super(struct super_block *sb)
1458{
1459 mb_cache_shrink(sb->s_bdev);
1460}
1461
1462/*
1463 * ext4_xattr_cache_insert()
1464 *
1465 * Create a new entry in the extended attribute cache, and insert
1466 * it unless such an entry is already in the cache.
1467 *
1468 * Returns 0, or a negative error number on failure.
1469 */
1470static void
1471ext4_xattr_cache_insert(struct buffer_head *bh)
1472{
1473 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1474 struct mb_cache_entry *ce;
1475 int error;
1476
1477 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1478 if (!ce) {
1479 ea_bdebug(bh, "out of memory");
1480 return;
1481 }
1482 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
1483 if (error) {
1484 mb_cache_entry_free(ce);
1485 if (error == -EBUSY) {
1486 ea_bdebug(bh, "already in cache");
1487 error = 0;
1488 }
1489 } else {
1490 ea_bdebug(bh, "inserting [%x]", (int)hash);
1491 mb_cache_entry_release(ce);
1492 }
1493}
1494
1495/*
1496 * ext4_xattr_cmp()
1497 *
1498 * Compare two extended attribute blocks for equality.
1499 *
1500 * Returns 0 if the blocks are equal, 1 if they differ, and
1501 * a negative error number on errors.
1502 */
1503static int
1504ext4_xattr_cmp(struct ext4_xattr_header *header1,
1505 struct ext4_xattr_header *header2)
1506{
1507 struct ext4_xattr_entry *entry1, *entry2;
1508
1509 entry1 = ENTRY(header1+1);
1510 entry2 = ENTRY(header2+1);
1511 while (!IS_LAST_ENTRY(entry1)) {
1512 if (IS_LAST_ENTRY(entry2))
1513 return 1;
1514 if (entry1->e_hash != entry2->e_hash ||
1515 entry1->e_name_index != entry2->e_name_index ||
1516 entry1->e_name_len != entry2->e_name_len ||
1517 entry1->e_value_size != entry2->e_value_size ||
1518 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1519 return 1;
1520 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1521 return -EIO;
1522 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1523 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1524 le32_to_cpu(entry1->e_value_size)))
1525 return 1;
1526
1527 entry1 = EXT4_XATTR_NEXT(entry1);
1528 entry2 = EXT4_XATTR_NEXT(entry2);
1529 }
1530 if (!IS_LAST_ENTRY(entry2))
1531 return 1;
1532 return 0;
1533}
1534
1535/*
1536 * ext4_xattr_cache_find()
1537 *
1538 * Find an identical extended attribute block.
1539 *
1540 * Returns a pointer to the block found, or NULL if such a block was
1541 * not found or an error occurred.
1542 */
1543static struct buffer_head *
1544ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1545 struct mb_cache_entry **pce)
1546{
1547 __u32 hash = le32_to_cpu(header->h_hash);
1548 struct mb_cache_entry *ce;
1549
1550 if (!header->h_hash)
1551 return NULL; /* never share */
1552 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1553again:
1554 ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev,
1555 hash);
1556 while (ce) {
1557 struct buffer_head *bh;
1558
1559 if (IS_ERR(ce)) {
1560 if (PTR_ERR(ce) == -EAGAIN)
1561 goto again;
1562 break;
1563 }
1564 bh = sb_bread(inode->i_sb, ce->e_block);
1565 if (!bh) {
1566 EXT4_ERROR_INODE(inode, "block %lu read error",
1567 (unsigned long) ce->e_block);
1568 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1569 EXT4_XATTR_REFCOUNT_MAX) {
1570 ea_idebug(inode, "block %lu refcount %d>=%d",
1571 (unsigned long) ce->e_block,
1572 le32_to_cpu(BHDR(bh)->h_refcount),
1573 EXT4_XATTR_REFCOUNT_MAX);
1574 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1575 *pce = ce;
1576 return bh;
1577 }
1578 brelse(bh);
1579 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
1580 }
1581 return NULL;
1582}
1583
1584#define NAME_HASH_SHIFT 5
1585#define VALUE_HASH_SHIFT 16
1586
1587/*
1588 * ext4_xattr_hash_entry()
1589 *
1590 * Compute the hash of an extended attribute.
1591 */
1592static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1593 struct ext4_xattr_entry *entry)
1594{
1595 __u32 hash = 0;
1596 char *name = entry->e_name;
1597 int n;
1598
1599 for (n = 0; n < entry->e_name_len; n++) {
1600 hash = (hash << NAME_HASH_SHIFT) ^
1601 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1602 *name++;
1603 }
1604
1605 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1606 __le32 *value = (__le32 *)((char *)header +
1607 le16_to_cpu(entry->e_value_offs));
1608 for (n = (le32_to_cpu(entry->e_value_size) +
1609 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1610 hash = (hash << VALUE_HASH_SHIFT) ^
1611 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1612 le32_to_cpu(*value++);
1613 }
1614 }
1615 entry->e_hash = cpu_to_le32(hash);
1616}
1617
1618#undef NAME_HASH_SHIFT
1619#undef VALUE_HASH_SHIFT
1620
1621#define BLOCK_HASH_SHIFT 16
1622
1623/*
1624 * ext4_xattr_rehash()
1625 *
1626 * Re-compute the extended attribute hash value after an entry has changed.
1627 */
1628static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1629 struct ext4_xattr_entry *entry)
1630{
1631 struct ext4_xattr_entry *here;
1632 __u32 hash = 0;
1633
1634 ext4_xattr_hash_entry(header, entry);
1635 here = ENTRY(header+1);
1636 while (!IS_LAST_ENTRY(here)) {
1637 if (!here->e_hash) {
1638 /* Block is not shared if an entry's hash value == 0 */
1639 hash = 0;
1640 break;
1641 }
1642 hash = (hash << BLOCK_HASH_SHIFT) ^
1643 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1644 le32_to_cpu(here->e_hash);
1645 here = EXT4_XATTR_NEXT(here);
1646 }
1647 header->h_hash = cpu_to_le32(hash);
1648}
1649
1650#undef BLOCK_HASH_SHIFT
1651
1652int __init
1653ext4_init_xattr(void)
1654{
1655 ext4_xattr_cache = mb_cache_create("ext4_xattr", 6);
1656 if (!ext4_xattr_cache)
1657 return -ENOMEM;
1658 return 0;
1659}
1660
1661void
1662ext4_exit_xattr(void)
1663{
1664 if (ext4_xattr_cache)
1665 mb_cache_destroy(ext4_xattr_cache);
1666 ext4_xattr_cache = NULL;
1667}