summaryrefslogtreecommitdiff
path: root/fs/erofs/xattr.c
blob: b766c3ee5fa8cbf955d0364687cb9cab97a92eac (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2017-2018 HUAWEI, Inc.
 *             http://www.huawei.com/
 * Created by Gao Xiang <gaoxiang25@huawei.com>
 */
#include <linux/security.h>
#include "xattr.h"

struct xattr_iter {
	struct super_block *sb;
	struct page *page;
	void *kaddr;

	erofs_blk_t blkaddr;
	unsigned int ofs;
};

static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
{
	/* the only user of kunmap() is 'init_inode_xattrs' */
	if (!atomic)
		kunmap(it->page);
	else
		kunmap_atomic(it->kaddr);

	unlock_page(it->page);
	put_page(it->page);
}

static inline void xattr_iter_end_final(struct xattr_iter *it)
{
	if (!it->page)
		return;

	xattr_iter_end(it, true);
}

static int init_inode_xattrs(struct inode *inode)
{
	struct erofs_inode *const vi = EROFS_I(inode);
	struct xattr_iter it;
	unsigned int i;
	struct erofs_xattr_ibody_header *ih;
	struct super_block *sb;
	struct erofs_sb_info *sbi;
	bool atomic_map;
	int ret = 0;

	/* the most case is that xattrs of this inode are initialized. */
	if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
		return 0;

	if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE))
		return -ERESTARTSYS;

	/* someone has initialized xattrs for us? */
	if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
		goto out_unlock;

	/*
	 * bypass all xattr operations if ->xattr_isize is not greater than
	 * sizeof(struct erofs_xattr_ibody_header), in detail:
	 * 1) it is not enough to contain erofs_xattr_ibody_header then
	 *    ->xattr_isize should be 0 (it means no xattr);
	 * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk
	 *    undefined right now (maybe use later with some new sb feature).
	 */
	if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) {
		erofs_err(inode->i_sb,
			  "xattr_isize %d of nid %llu is not supported yet",
			  vi->xattr_isize, vi->nid);
		ret = -EOPNOTSUPP;
		goto out_unlock;
	} else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) {
		if (vi->xattr_isize) {
			erofs_err(inode->i_sb,
				  "bogus xattr ibody @ nid %llu", vi->nid);
			DBG_BUGON(1);
			ret = -EFSCORRUPTED;
			goto out_unlock;	/* xattr ondisk layout error */
		}
		ret = -ENOATTR;
		goto out_unlock;
	}

	sb = inode->i_sb;
	sbi = EROFS_SB(sb);
	it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
	it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);

	it.page = erofs_get_meta_page(sb, it.blkaddr);
	if (IS_ERR(it.page)) {
		ret = PTR_ERR(it.page);
		goto out_unlock;
	}

	/* read in shared xattr array (non-atomic, see kmalloc below) */
	it.kaddr = kmap(it.page);
	atomic_map = false;

	ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);

	vi->xattr_shared_count = ih->h_shared_count;
	vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
						sizeof(uint), GFP_KERNEL);
	if (!vi->xattr_shared_xattrs) {
		xattr_iter_end(&it, atomic_map);
		ret = -ENOMEM;
		goto out_unlock;
	}

	/* let's skip ibody header */
	it.ofs += sizeof(struct erofs_xattr_ibody_header);

	for (i = 0; i < vi->xattr_shared_count; ++i) {
		if (it.ofs >= EROFS_BLKSIZ) {
			/* cannot be unaligned */
			DBG_BUGON(it.ofs != EROFS_BLKSIZ);
			xattr_iter_end(&it, atomic_map);

			it.page = erofs_get_meta_page(sb, ++it.blkaddr);
			if (IS_ERR(it.page)) {
				kfree(vi->xattr_shared_xattrs);
				vi->xattr_shared_xattrs = NULL;
				ret = PTR_ERR(it.page);
				goto out_unlock;
			}

			it.kaddr = kmap_atomic(it.page);
			atomic_map = true;
			it.ofs = 0;
		}
		vi->xattr_shared_xattrs[i] =
			le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
		it.ofs += sizeof(__le32);
	}
	xattr_iter_end(&it, atomic_map);

	set_bit(EROFS_I_EA_INITED_BIT, &vi->flags);

out_unlock:
	clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);
	return ret;
}

/*
 * the general idea for these return values is
 * if    0 is returned, go on processing the current xattr;
 *       1 (> 0) is returned, skip this round to process the next xattr;
 *    -err (< 0) is returned, an error (maybe ENOXATTR) occurred
 *                            and need to be handled
 */
struct xattr_iter_handlers {
	int (*entry)(struct xattr_iter *_it, struct erofs_xattr_entry *entry);
	int (*name)(struct xattr_iter *_it, unsigned int processed, char *buf,
		    unsigned int len);
	int (*alloc_buffer)(struct xattr_iter *_it, unsigned int value_sz);
	void (*value)(struct xattr_iter *_it, unsigned int processed, char *buf,
		      unsigned int len);
};

static inline int xattr_iter_fixup(struct xattr_iter *it)
{
	if (it->ofs < EROFS_BLKSIZ)
		return 0;

	xattr_iter_end(it, true);

	it->blkaddr += erofs_blknr(it->ofs);

	it->page = erofs_get_meta_page(it->sb, it->blkaddr);
	if (IS_ERR(it->page)) {
		int err = PTR_ERR(it->page);

		it->page = NULL;
		return err;
	}

	it->kaddr = kmap_atomic(it->page);
	it->ofs = erofs_blkoff(it->ofs);
	return 0;
}

static int inline_xattr_iter_begin(struct xattr_iter *it,
				   struct inode *inode)
{
	struct erofs_inode *const vi = EROFS_I(inode);
	struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
	unsigned int xattr_header_sz, inline_xattr_ofs;

	xattr_header_sz = inlinexattr_header_size(inode);
	if (xattr_header_sz >= vi->xattr_isize) {
		DBG_BUGON(xattr_header_sz > vi->xattr_isize);
		return -ENOATTR;
	}

	inline_xattr_ofs = vi->inode_isize + xattr_header_sz;

	it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
	it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);

	it->page = erofs_get_meta_page(inode->i_sb, it->blkaddr);
	if (IS_ERR(it->page))
		return PTR_ERR(it->page);

	it->kaddr = kmap_atomic(it->page);
	return vi->xattr_isize - xattr_header_sz;
}

/*
 * Regardless of success or failure, `xattr_foreach' will end up with
 * `ofs' pointing to the next xattr item rather than an arbitrary position.
 */
static int xattr_foreach(struct xattr_iter *it,
			 const struct xattr_iter_handlers *op,
			 unsigned int *tlimit)
{
	struct erofs_xattr_entry entry;
	unsigned int value_sz, processed, slice;
	int err;

	/* 0. fixup blkaddr, ofs, ipage */
	err = xattr_iter_fixup(it);
	if (err)
		return err;

	/*
	 * 1. read xattr entry to the memory,
	 *    since we do EROFS_XATTR_ALIGN
	 *    therefore entry should be in the page
	 */
	entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
	if (tlimit) {
		unsigned int entry_sz = erofs_xattr_entry_size(&entry);

		/* xattr on-disk corruption: xattr entry beyond xattr_isize */
		if (*tlimit < entry_sz) {
			DBG_BUGON(1);
			return -EFSCORRUPTED;
		}
		*tlimit -= entry_sz;
	}

	it->ofs += sizeof(struct erofs_xattr_entry);
	value_sz = le16_to_cpu(entry.e_value_size);

	/* handle entry */
	err = op->entry(it, &entry);
	if (err) {
		it->ofs += entry.e_name_len + value_sz;
		goto out;
	}

	/* 2. handle xattr name (ofs will finally be at the end of name) */
	processed = 0;

	while (processed < entry.e_name_len) {
		if (it->ofs >= EROFS_BLKSIZ) {
			DBG_BUGON(it->ofs > EROFS_BLKSIZ);

			err = xattr_iter_fixup(it);
			if (err)
				goto out;
			it->ofs = 0;
		}

		slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
			      entry.e_name_len - processed);

		/* handle name */
		err = op->name(it, processed, it->kaddr + it->ofs, slice);
		if (err) {
			it->ofs += entry.e_name_len - processed + value_sz;
			goto out;
		}

		it->ofs += slice;
		processed += slice;
	}

	/* 3. handle xattr value */
	processed = 0;

	if (op->alloc_buffer) {
		err = op->alloc_buffer(it, value_sz);
		if (err) {
			it->ofs += value_sz;
			goto out;
		}
	}

	while (processed < value_sz) {
		if (it->ofs >= EROFS_BLKSIZ) {
			DBG_BUGON(it->ofs > EROFS_BLKSIZ);

			err = xattr_iter_fixup(it);
			if (err)
				goto out;
			it->ofs = 0;
		}

		slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
			      value_sz - processed);
		op->value(it, processed, it->kaddr + it->ofs, slice);
		it->ofs += slice;
		processed += slice;
	}

out:
	/* xattrs should be 4-byte aligned (on-disk constraint) */
	it->ofs = EROFS_XATTR_ALIGN(it->ofs);
	return err < 0 ? err : 0;
}

struct getxattr_iter {
	struct xattr_iter it;

	char *buffer;
	int buffer_size, index;
	struct qstr name;
};

static int xattr_entrymatch(struct xattr_iter *_it,
			    struct erofs_xattr_entry *entry)
{
	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);

	return (it->index != entry->e_name_index ||
		it->name.len != entry->e_name_len) ? -ENOATTR : 0;
}

static int xattr_namematch(struct xattr_iter *_it,
			   unsigned int processed, char *buf, unsigned int len)
{
	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);

	return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;
}

static int xattr_checkbuffer(struct xattr_iter *_it,
			     unsigned int value_sz)
{
	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
	int err = it->buffer_size < value_sz ? -ERANGE : 0;

	it->buffer_size = value_sz;
	return !it->buffer ? 1 : err;
}

static void xattr_copyvalue(struct xattr_iter *_it,
			    unsigned int processed,
			    char *buf, unsigned int len)
{
	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);

	memcpy(it->buffer + processed, buf, len);
}

static const struct xattr_iter_handlers find_xattr_handlers = {
	.entry = xattr_entrymatch,
	.name = xattr_namematch,
	.alloc_buffer = xattr_checkbuffer,
	.value = xattr_copyvalue
};

static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
{
	int ret;
	unsigned int remaining;

	ret = inline_xattr_iter_begin(&it->it, inode);
	if (ret < 0)
		return ret;

	remaining = ret;
	while (remaining) {
		ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining);
		if (ret != -ENOATTR)
			break;
	}
	xattr_iter_end_final(&it->it);

	return ret ? ret : it->buffer_size;
}

static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
{
	struct erofs_inode *const vi = EROFS_I(inode);
	struct super_block *const sb = inode->i_sb;
	struct erofs_sb_info *const sbi = EROFS_SB(sb);
	unsigned int i;
	int ret = -ENOATTR;

	for (i = 0; i < vi->xattr_shared_count; ++i) {
		erofs_blk_t blkaddr =
			xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);

		it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);

		if (!i || blkaddr != it->it.blkaddr) {
			if (i)
				xattr_iter_end(&it->it, true);

			it->it.page = erofs_get_meta_page(sb, blkaddr);
			if (IS_ERR(it->it.page))
				return PTR_ERR(it->it.page);

			it->it.kaddr = kmap_atomic(it->it.page);
			it->it.blkaddr = blkaddr;
		}

		ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL);
		if (ret != -ENOATTR)
			break;
	}
	if (vi->xattr_shared_count)
		xattr_iter_end_final(&it->it);

	return ret ? ret : it->buffer_size;
}

static bool erofs_xattr_user_list(struct dentry *dentry)
{
	return test_opt(EROFS_SB(dentry->d_sb), XATTR_USER);
}

static bool erofs_xattr_trusted_list(struct dentry *dentry)
{
	return capable(CAP_SYS_ADMIN);
}

int erofs_getxattr(struct inode *inode, int index,
		   const char *name,
		   void *buffer, size_t buffer_size)
{
	int ret;
	struct getxattr_iter it;

	if (!name)
		return -EINVAL;

	ret = init_inode_xattrs(inode);
	if (ret)
		return ret;

	it.index = index;

	it.name.len = strlen(name);
	if (it.name.len > EROFS_NAME_LEN)
		return -ERANGE;
	it.name.name = name;

	it.buffer = buffer;
	it.buffer_size = buffer_size;

	it.it.sb = inode->i_sb;
	ret = inline_getxattr(inode, &it);
	if (ret == -ENOATTR)
		ret = shared_getxattr(inode, &it);
	return ret;
}

static int erofs_xattr_generic_get(const struct xattr_handler *handler,
				   struct dentry *unused, struct inode *inode,
				   const char *name, void *buffer, size_t size)
{
	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);

	switch (handler->flags) {
	case EROFS_XATTR_INDEX_USER:
		if (!test_opt(sbi, XATTR_USER))
			return -EOPNOTSUPP;
		break;
	case EROFS_XATTR_INDEX_TRUSTED:
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;
		break;
	case EROFS_XATTR_INDEX_SECURITY:
		break;
	default:
		return -EINVAL;
	}

	return erofs_getxattr(inode, handler->flags, name, buffer, size);
}

const struct xattr_handler erofs_xattr_user_handler = {
	.prefix	= XATTR_USER_PREFIX,
	.flags	= EROFS_XATTR_INDEX_USER,
	.list	= erofs_xattr_user_list,
	.get	= erofs_xattr_generic_get,
};

const struct xattr_handler erofs_xattr_trusted_handler = {
	.prefix	= XATTR_TRUSTED_PREFIX,
	.flags	= EROFS_XATTR_INDEX_TRUSTED,
	.list	= erofs_xattr_trusted_list,
	.get	= erofs_xattr_generic_get,
};

#ifdef CONFIG_EROFS_FS_SECURITY
const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
	.prefix	= XATTR_SECURITY_PREFIX,
	.flags	= EROFS_XATTR_INDEX_SECURITY,
	.get	= erofs_xattr_generic_get,
};
#endif

const struct xattr_handler *erofs_xattr_handlers[] = {
	&erofs_xattr_user_handler,
#ifdef CONFIG_EROFS_FS_POSIX_ACL
	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_handler,
#endif
	&erofs_xattr_trusted_handler,
#ifdef CONFIG_EROFS_FS_SECURITY
	&erofs_xattr_security_handler,
#endif
	NULL,
};

struct listxattr_iter {
	struct xattr_iter it;

	struct dentry *dentry;
	char *buffer;
	int buffer_size, buffer_ofs;
};

static int xattr_entrylist(struct xattr_iter *_it,
			   struct erofs_xattr_entry *entry)
{
	struct listxattr_iter *it =
		container_of(_it, struct listxattr_iter, it);
	unsigned int prefix_len;
	const char *prefix;

	const struct xattr_handler *h =
		erofs_xattr_handler(entry->e_name_index);

	if (!h || (h->list && !h->list(it->dentry)))
		return 1;

	prefix = xattr_prefix(h);
	prefix_len = strlen(prefix);

	if (!it->buffer) {
		it->buffer_ofs += prefix_len + entry->e_name_len + 1;
		return 1;
	}

	if (it->buffer_ofs + prefix_len
		+ entry->e_name_len + 1 > it->buffer_size)
		return -ERANGE;

	memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
	it->buffer_ofs += prefix_len;
	return 0;
}

static int xattr_namelist(struct xattr_iter *_it,
			  unsigned int processed, char *buf, unsigned int len)
{
	struct listxattr_iter *it =
		container_of(_it, struct listxattr_iter, it);

	memcpy(it->buffer + it->buffer_ofs, buf, len);
	it->buffer_ofs += len;
	return 0;
}

static int xattr_skipvalue(struct xattr_iter *_it,
			   unsigned int value_sz)
{
	struct listxattr_iter *it =
		container_of(_it, struct listxattr_iter, it);

	it->buffer[it->buffer_ofs++] = '\0';
	return 1;
}

static const struct xattr_iter_handlers list_xattr_handlers = {
	.entry = xattr_entrylist,
	.name = xattr_namelist,
	.alloc_buffer = xattr_skipvalue,
	.value = NULL
};

static int inline_listxattr(struct listxattr_iter *it)
{
	int ret;
	unsigned int remaining;

	ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry));
	if (ret < 0)
		return ret;

	remaining = ret;
	while (remaining) {
		ret = xattr_foreach(&it->it, &list_xattr_handlers, &remaining);
		if (ret)
			break;
	}
	xattr_iter_end_final(&it->it);
	return ret ? ret : it->buffer_ofs;
}

static int shared_listxattr(struct listxattr_iter *it)
{
	struct inode *const inode = d_inode(it->dentry);
	struct erofs_inode *const vi = EROFS_I(inode);
	struct super_block *const sb = inode->i_sb;
	struct erofs_sb_info *const sbi = EROFS_SB(sb);
	unsigned int i;
	int ret = 0;

	for (i = 0; i < vi->xattr_shared_count; ++i) {
		erofs_blk_t blkaddr =
			xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);

		it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
		if (!i || blkaddr != it->it.blkaddr) {
			if (i)
				xattr_iter_end(&it->it, true);

			it->it.page = erofs_get_meta_page(sb, blkaddr);
			if (IS_ERR(it->it.page))
				return PTR_ERR(it->it.page);

			it->it.kaddr = kmap_atomic(it->it.page);
			it->it.blkaddr = blkaddr;
		}

		ret = xattr_foreach(&it->it, &list_xattr_handlers, NULL);
		if (ret)
			break;
	}
	if (vi->xattr_shared_count)
		xattr_iter_end_final(&it->it);

	return ret ? ret : it->buffer_ofs;
}

ssize_t erofs_listxattr(struct dentry *dentry,
			char *buffer, size_t buffer_size)
{
	int ret;
	struct listxattr_iter it;

	ret = init_inode_xattrs(d_inode(dentry));
	if (ret == -ENOATTR)
		return 0;
	if (ret)
		return ret;

	it.dentry = dentry;
	it.buffer = buffer;
	it.buffer_size = buffer_size;
	it.buffer_ofs = 0;

	it.it.sb = dentry->d_sb;

	ret = inline_listxattr(&it);
	if (ret < 0 && ret != -ENOATTR)
		return ret;
	return shared_listxattr(&it);
}

#ifdef CONFIG_EROFS_FS_POSIX_ACL
struct posix_acl *erofs_get_acl(struct inode *inode, int type)
{
	struct posix_acl *acl;
	int prefix, rc;
	char *value = NULL;

	switch (type) {
	case ACL_TYPE_ACCESS:
		prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
		break;
	default:
		return ERR_PTR(-EINVAL);
	}

	rc = erofs_getxattr(inode, prefix, "", NULL, 0);
	if (rc > 0) {
		value = kmalloc(rc, GFP_KERNEL);
		if (!value)
			return ERR_PTR(-ENOMEM);
		rc = erofs_getxattr(inode, prefix, "", value, rc);
	}

	if (rc == -ENOATTR)
		acl = NULL;
	else if (rc < 0)
		acl = ERR_PTR(rc);
	else
		acl = posix_acl_from_xattr(&init_user_ns, value, rc);
	kfree(value);
	return acl;
}
#endif