summaryrefslogtreecommitdiff
path: root/fs/ubifs/xattr.c
blob: 0847db521984ac98a4de135e984c47ed703837d0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
// SPDX-License-Identifier: GPL-2.0-only
/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * Authors: Artem Bityutskiy (Битюцкий Артём)
 *          Adrian Hunter
 */

/*
 * This file implements UBIFS extended attributes support.
 *
 * Extended attributes are implemented as regular inodes with attached data,
 * which limits extended attribute size to UBIFS block size (4KiB). Names of
 * extended attributes are described by extended attribute entries (xentries),
 * which are almost identical to directory entries, but have different key type.
 *
 * In other words, the situation with extended attributes is very similar to
 * directories. Indeed, any inode (but of course not xattr inodes) may have a
 * number of associated xentries, just like directory inodes have associated
 * directory entries. Extended attribute entries store the name of the extended
 * attribute, the host inode number, and the extended attribute inode number.
 * Similarly, direntries store the name, the parent and the target inode
 * numbers. Thus, most of the common UBIFS mechanisms may be re-used for
 * extended attributes.
 *
 * The number of extended attributes is not limited, but there is Linux
 * limitation on the maximum possible size of the list of all extended
 * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
 * the sum of all extended attribute names of the inode does not exceed that
 * limit.
 *
 * Extended attributes are synchronous, which means they are written to the
 * flash media synchronously and there is no write-back for extended attribute
 * inodes. The extended attribute values are not stored in compressed form on
 * the media.
 *
 * Since extended attributes are represented by regular inodes, they are cached
 * in the VFS inode cache. The xentries are cached in the LNC cache (see
 * tnc.c).
 *
 * ACL support is not implemented.
 */

#include "ubifs.h"
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/xattr.h>

/*
 * Extended attribute type constants.
 *
 * USER_XATTR: user extended attribute ("user.*")
 * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
 * SECURITY_XATTR: security extended attribute ("security.*")
 */
enum {
	USER_XATTR,
	TRUSTED_XATTR,
	SECURITY_XATTR,
};

static const struct inode_operations empty_iops;
static const struct file_operations empty_fops;

/**
 * create_xattr - create an extended attribute.
 * @c: UBIFS file-system description object
 * @host: host inode
 * @nm: extended attribute name
 * @value: extended attribute value
 * @size: size of extended attribute value
 *
 * This is a helper function which creates an extended attribute of name @nm
 * and value @value for inode @host. The host inode is also updated on flash
 * because the ctime and extended attribute accounting data changes. This
 * function returns zero in case of success and a negative error code in case
 * of failure.
 */
static int create_xattr(struct ubifs_info *c, struct inode *host,
			const struct fscrypt_name *nm, const void *value, int size)
{
	int err, names_len;
	struct inode *inode;
	struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
				.new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
				.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };

	if (host_ui->xattr_cnt >= ubifs_xattr_max_cnt(c)) {
		ubifs_err(c, "inode %lu already has too many xattrs (%d), cannot create more",
			  host->i_ino, host_ui->xattr_cnt);
		return -ENOSPC;
	}
	/*
	 * Linux limits the maximum size of the extended attribute names list
	 * to %XATTR_LIST_MAX. This means we should not allow creating more
	 * extended attributes if the name list becomes larger. This limitation
	 * is artificial for UBIFS, though.
	 */
	names_len = host_ui->xattr_names + host_ui->xattr_cnt + fname_len(nm) + 1;
	if (names_len > XATTR_LIST_MAX) {
		ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d",
			  host->i_ino, names_len, XATTR_LIST_MAX);
		return -ENOSPC;
	}

	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO, true);
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_budg;
	}

	/* Re-define all operations to be "nothing" */
	inode->i_mapping->a_ops = &empty_aops;
	inode->i_op = &empty_iops;
	inode->i_fop = &empty_fops;

	inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME;
	ui = ubifs_inode(inode);
	ui->xattr = 1;
	ui->flags |= UBIFS_XATTR_FL;
	ui->data = kmemdup(value, size, GFP_NOFS);
	if (!ui->data) {
		err = -ENOMEM;
		goto out_free;
	}
	inode->i_size = ui->ui_size = size;
	ui->data_len = size;

	mutex_lock(&host_ui->ui_mutex);
	inode_set_ctime_current(host);
	host_ui->xattr_cnt += 1;
	host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
	host_ui->xattr_size += CALC_XATTR_BYTES(size);
	host_ui->xattr_names += fname_len(nm);

	/*
	 * We handle UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT here because we
	 * have to set the UBIFS_CRYPT_FL flag on the host inode.
	 * To avoid multiple updates of the same inode in the same operation,
	 * let's do it here.
	 */
	if (strcmp(fname_name(nm), UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
		host_ui->flags |= UBIFS_CRYPT_FL;

	err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
	if (err)
		goto out_cancel;
	ubifs_set_inode_flags(host);
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	insert_inode_hash(inode);
	iput(inode);
	return 0;

out_cancel:
	host_ui->xattr_cnt -= 1;
	host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
	host_ui->xattr_names -= fname_len(nm);
	host_ui->flags &= ~UBIFS_CRYPT_FL;
	mutex_unlock(&host_ui->ui_mutex);
out_free:
	make_bad_inode(inode);
	iput(inode);
out_budg:
	ubifs_release_budget(c, &req);
	return err;
}

/**
 * change_xattr - change an extended attribute.
 * @c: UBIFS file-system description object
 * @host: host inode
 * @inode: extended attribute inode
 * @value: extended attribute value
 * @size: size of extended attribute value
 *
 * This helper function changes the value of extended attribute @inode with new
 * data from @value. Returns zero in case of success and a negative error code
 * in case of failure.
 */
static int change_xattr(struct ubifs_info *c, struct inode *host,
			struct inode *inode, const void *value, int size)
{
	int err;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_inode *ui = ubifs_inode(inode);
	void *buf = NULL;
	int old_size;
	struct ubifs_budget_req req = { .dirtied_ino = 2,
		.dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };

	ubifs_assert(c, ui->data_len == inode->i_size);
	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	buf = kmemdup(value, size, GFP_NOFS);
	if (!buf) {
		err = -ENOMEM;
		goto out_free;
	}
	kfree(ui->data);
	ui->data = buf;
	inode->i_size = ui->ui_size = size;
	old_size = ui->data_len;
	ui->data_len = size;

	mutex_lock(&host_ui->ui_mutex);
	inode_set_ctime_current(host);
	host_ui->xattr_size -= CALC_XATTR_BYTES(old_size);
	host_ui->xattr_size += CALC_XATTR_BYTES(size);

	/*
	 * It is important to write the host inode after the xattr inode
	 * because if the host inode gets synchronized (via 'fsync()'), then
	 * the extended attribute inode gets synchronized, because it goes
	 * before the host inode in the write-buffer.
	 */
	err = ubifs_jnl_change_xattr(c, inode, host);
	if (err)
		goto out_cancel;
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	return 0;

out_cancel:
	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
	host_ui->xattr_size += CALC_XATTR_BYTES(old_size);
	mutex_unlock(&host_ui->ui_mutex);
	make_bad_inode(inode);
out_free:
	ubifs_release_budget(c, &req);
	return err;
}

static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
{
	struct inode *inode;

	inode = ubifs_iget(c->vfs_sb, inum);
	if (IS_ERR(inode)) {
		ubifs_err(c, "dead extended attribute entry, error %d",
			  (int)PTR_ERR(inode));
		return inode;
	}
	if (ubifs_inode(inode)->xattr)
		return inode;
	ubifs_err(c, "corrupt extended attribute entry");
	iput(inode);
	return ERR_PTR(-EINVAL);
}

int ubifs_xattr_set(struct inode *host, const char *name, const void *value,
		    size_t size, int flags, bool check_lock)
{
	struct inode *inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err;

	if (check_lock)
		ubifs_assert(c, inode_is_locked(host));

	if (size > UBIFS_MAX_INO_DATA)
		return -ERANGE;

	if (fname_len(&nm) > UBIFS_MAX_NLEN)
		return -ENAMETOOLONG;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	down_write(&ubifs_inode(host)->xattr_sem);
	/*
	 * The extended attribute entries are stored in LNC, so multiple
	 * look-ups do not involve reading the flash.
	 */
	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err != -ENOENT)
			goto out_free;

		if (flags & XATTR_REPLACE)
			/* We are asked not to create the xattr */
			err = -ENODATA;
		else
			err = create_xattr(c, host, &nm, value, size);
		goto out_free;
	}

	if (flags & XATTR_CREATE) {
		/* We are asked not to replace the xattr */
		err = -EEXIST;
		goto out_free;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_free;
	}

	err = change_xattr(c, host, inode, value, size);
	iput(inode);

out_free:
	up_write(&ubifs_inode(host)->xattr_sem);
	kfree(xent);
	return err;
}

ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
			size_t size)
{
	struct inode *inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
	struct ubifs_inode *ui;
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err;

	if (fname_len(&nm) > UBIFS_MAX_NLEN)
		return -ENAMETOOLONG;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	down_read(&ubifs_inode(host)->xattr_sem);
	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err == -ENOENT)
			err = -ENODATA;
		goto out_cleanup;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_cleanup;
	}

	ui = ubifs_inode(inode);
	ubifs_assert(c, inode->i_size == ui->data_len);
	ubifs_assert(c, ubifs_inode(host)->xattr_size > ui->data_len);

	if (buf) {
		/* If @buf is %NULL we are supposed to return the length */
		if (ui->data_len > size) {
			err = -ERANGE;
			goto out_iput;
		}

		memcpy(buf, ui->data, ui->data_len);
	}
	err = ui->data_len;

out_iput:
	iput(inode);
out_cleanup:
	up_read(&ubifs_inode(host)->xattr_sem);
	kfree(xent);
	return err;
}

static bool xattr_visible(const char *name)
{
	/* File encryption related xattrs are for internal use only */
	if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
		return false;

	/* Show trusted namespace only for "power" users */
	if (strncmp(name, XATTR_TRUSTED_PREFIX,
		    XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN))
		return false;

	return true;
}

ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	union ubifs_key key;
	struct inode *host = d_inode(dentry);
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_dent_node *xent, *pxent = NULL;
	int err, len, written = 0;
	struct fscrypt_name nm = {0};

	dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
		dentry, size);

	down_read(&host_ui->xattr_sem);
	len = host_ui->xattr_names + host_ui->xattr_cnt;
	if (!buffer) {
		/*
		 * We should return the minimum buffer size which will fit a
		 * null-terminated list of all the extended attribute names.
		 */
		err = len;
		goto out_err;
	}

	if (len > size) {
		err = -ERANGE;
		goto out_err;
	}

	lowest_xent_key(c, &key, host->i_ino);
	while (1) {
		xent = ubifs_tnc_next_ent(c, &key, &nm);
		if (IS_ERR(xent)) {
			err = PTR_ERR(xent);
			break;
		}

		fname_name(&nm) = xent->name;
		fname_len(&nm) = le16_to_cpu(xent->nlen);

		if (xattr_visible(xent->name)) {
			memcpy(buffer + written, fname_name(&nm), fname_len(&nm) + 1);
			written += fname_len(&nm) + 1;
		}

		kfree(pxent);
		pxent = xent;
		key_read(c, &xent->key, &key);
	}
	kfree(pxent);
	up_read(&host_ui->xattr_sem);

	if (err != -ENOENT) {
		ubifs_err(c, "cannot find next direntry, error %d", err);
		return err;
	}

	ubifs_assert(c, written <= size);
	return written;

out_err:
	up_read(&host_ui->xattr_sem);
	return err;
}

static int remove_xattr(struct ubifs_info *c, struct inode *host,
			struct inode *inode, const struct fscrypt_name *nm)
{
	int err;
	struct ubifs_inode *host_ui = ubifs_inode(host);
	struct ubifs_inode *ui = ubifs_inode(inode);
	struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
				.dirtied_ino_d = ALIGN(host_ui->data_len, 8) };

	ubifs_assert(c, ui->data_len == inode->i_size);

	err = ubifs_budget_space(c, &req);
	if (err)
		return err;

	mutex_lock(&host_ui->ui_mutex);
	inode_set_ctime_current(host);
	host_ui->xattr_cnt -= 1;
	host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
	host_ui->xattr_names -= fname_len(nm);

	err = ubifs_jnl_delete_xattr(c, host, inode, nm);
	if (err)
		goto out_cancel;
	mutex_unlock(&host_ui->ui_mutex);

	ubifs_release_budget(c, &req);
	return 0;

out_cancel:
	host_ui->xattr_cnt += 1;
	host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
	host_ui->xattr_names += fname_len(nm);
	mutex_unlock(&host_ui->ui_mutex);
	ubifs_release_budget(c, &req);
	make_bad_inode(inode);
	return err;
}

int ubifs_purge_xattrs(struct inode *host)
{
	union ubifs_key key;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct ubifs_dent_node *xent, *pxent = NULL;
	struct inode *xino;
	struct fscrypt_name nm = {0};
	int err;

	if (ubifs_inode(host)->xattr_cnt <= ubifs_xattr_max_cnt(c))
		return 0;

	ubifs_warn(c, "inode %lu has too many xattrs, doing a non-atomic deletion",
		   host->i_ino);

	down_write(&ubifs_inode(host)->xattr_sem);
	lowest_xent_key(c, &key, host->i_ino);
	while (1) {
		xent = ubifs_tnc_next_ent(c, &key, &nm);
		if (IS_ERR(xent)) {
			err = PTR_ERR(xent);
			break;
		}

		fname_name(&nm) = xent->name;
		fname_len(&nm) = le16_to_cpu(xent->nlen);

		xino = ubifs_iget(c->vfs_sb, le64_to_cpu(xent->inum));
		if (IS_ERR(xino)) {
			err = PTR_ERR(xino);
			ubifs_err(c, "dead directory entry '%s', error %d",
				  xent->name, err);
			ubifs_ro_mode(c, err);
			kfree(pxent);
			kfree(xent);
			goto out_err;
		}

		ubifs_assert(c, ubifs_inode(xino)->xattr);

		clear_nlink(xino);
		err = remove_xattr(c, host, xino, &nm);
		if (err) {
			kfree(pxent);
			kfree(xent);
			iput(xino);
			ubifs_err(c, "cannot remove xattr, error %d", err);
			goto out_err;
		}

		iput(xino);

		kfree(pxent);
		pxent = xent;
		key_read(c, &xent->key, &key);
	}
	kfree(pxent);
	up_write(&ubifs_inode(host)->xattr_sem);

	if (err != -ENOENT) {
		ubifs_err(c, "cannot find next direntry, error %d", err);
		return err;
	}

	return 0;

out_err:
	up_write(&ubifs_inode(host)->xattr_sem);
	return err;
}

/**
 * ubifs_evict_xattr_inode - Evict an xattr inode.
 * @c: UBIFS file-system description object
 * @xattr_inum: xattr inode number
 *
 * When an inode that hosts xattrs is being removed we have to make sure
 * that cached inodes of the xattrs also get removed from the inode cache
 * otherwise we'd waste memory. This function looks up an inode from the
 * inode cache and clears the link counter such that iput() will evict
 * the inode.
 */
void ubifs_evict_xattr_inode(struct ubifs_info *c, ino_t xattr_inum)
{
	struct inode *inode;

	inode = ilookup(c->vfs_sb, xattr_inum);
	if (inode) {
		clear_nlink(inode);
		iput(inode);
	}
}

static int ubifs_xattr_remove(struct inode *host, const char *name)
{
	struct inode *inode;
	struct ubifs_info *c = host->i_sb->s_fs_info;
	struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
	struct ubifs_dent_node *xent;
	union ubifs_key key;
	int err;

	ubifs_assert(c, inode_is_locked(host));

	if (fname_len(&nm) > UBIFS_MAX_NLEN)
		return -ENAMETOOLONG;

	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
	if (!xent)
		return -ENOMEM;

	down_write(&ubifs_inode(host)->xattr_sem);
	xent_key_init(c, &key, host->i_ino, &nm);
	err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
	if (err) {
		if (err == -ENOENT)
			err = -ENODATA;
		goto out_free;
	}

	inode = iget_xattr(c, le64_to_cpu(xent->inum));
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out_free;
	}

	ubifs_assert(c, inode->i_nlink == 1);
	clear_nlink(inode);
	err = remove_xattr(c, host, inode, &nm);
	if (err)
		set_nlink(inode, 1);

	/* If @i_nlink is 0, 'iput()' will delete the inode */
	iput(inode);

out_free:
	up_write(&ubifs_inode(host)->xattr_sem);
	kfree(xent);
	return err;
}

#ifdef CONFIG_UBIFS_FS_SECURITY
static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
		      void *fs_info)
{
	const struct xattr *xattr;
	char *name;
	int err = 0;

	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
		name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
			       strlen(xattr->name) + 1, GFP_NOFS);
		if (!name) {
			err = -ENOMEM;
			break;
		}
		strcpy(name, XATTR_SECURITY_PREFIX);
		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
		/*
		 * creating a new inode without holding the inode rwsem,
		 * no need to check whether inode is locked.
		 */
		err = ubifs_xattr_set(inode, name, xattr->value,
				      xattr->value_len, 0, false);
		kfree(name);
		if (err < 0)
			break;
	}

	return err;
}

int ubifs_init_security(struct inode *dentry, struct inode *inode,
			const struct qstr *qstr)
{
	int err;

	err = security_inode_init_security(inode, dentry, qstr,
					   &init_xattrs, NULL);
	if (err) {
		struct ubifs_info *c = dentry->i_sb->s_fs_info;
		ubifs_err(c, "cannot initialize security for inode %lu, error %d",
			  inode->i_ino, err);
	}
	return err;
}
#endif

static int xattr_get(const struct xattr_handler *handler,
			   struct dentry *dentry, struct inode *inode,
			   const char *name, void *buffer, size_t size)
{
	dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
		inode->i_ino, dentry, size);

	name = xattr_full_name(handler, name);
	return ubifs_xattr_get(inode, name, buffer, size);
}

static int xattr_set(const struct xattr_handler *handler,
			   struct mnt_idmap *idmap,
			   struct dentry *dentry, struct inode *inode,
			   const char *name, const void *value,
			   size_t size, int flags)
{
	dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
		name, inode->i_ino, dentry, size);

	name = xattr_full_name(handler, name);

	if (value)
		return ubifs_xattr_set(inode, name, value, size, flags, true);
	else
		return ubifs_xattr_remove(inode, name);
}

static const struct xattr_handler ubifs_user_xattr_handler = {
	.prefix = XATTR_USER_PREFIX,
	.get = xattr_get,
	.set = xattr_set,
};

static const struct xattr_handler ubifs_trusted_xattr_handler = {
	.prefix = XATTR_TRUSTED_PREFIX,
	.get = xattr_get,
	.set = xattr_set,
};

#ifdef CONFIG_UBIFS_FS_SECURITY
static const struct xattr_handler ubifs_security_xattr_handler = {
	.prefix = XATTR_SECURITY_PREFIX,
	.get = xattr_get,
	.set = xattr_set,
};
#endif

const struct xattr_handler * const ubifs_xattr_handlers[] = {
	&ubifs_user_xattr_handler,
	&ubifs_trusted_xattr_handler,
#ifdef CONFIG_UBIFS_FS_SECURITY
	&ubifs_security_xattr_handler,
#endif
	NULL
};