xref: /linux/fs/erofs/xattr.c (revision 56fb34d86e875dbb0d3e6a81c5d3d035db373031) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2017-2018 HUAWEI, Inc.
4  *             http://www.huawei.com/
5  * Created by Gao Xiang <gaoxiang25@huawei.com>
6  */
7 #include <linux/security.h>
8 #include "xattr.h"
9 
10 struct xattr_iter {
11 	struct super_block *sb;
12 	struct page *page;
13 	void *kaddr;
14 
15 	erofs_blk_t blkaddr;
16 	unsigned int ofs;
17 };
18 
19 static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
20 {
21 	/* the only user of kunmap() is 'init_inode_xattrs' */
22 	if (!atomic)
23 		kunmap(it->page);
24 	else
25 		kunmap_atomic(it->kaddr);
26 
27 	unlock_page(it->page);
28 	put_page(it->page);
29 }
30 
31 static inline void xattr_iter_end_final(struct xattr_iter *it)
32 {
33 	if (!it->page)
34 		return;
35 
36 	xattr_iter_end(it, true);
37 }
38 
39 static int init_inode_xattrs(struct inode *inode)
40 {
41 	struct erofs_inode *const vi = EROFS_I(inode);
42 	struct xattr_iter it;
43 	unsigned int i;
44 	struct erofs_xattr_ibody_header *ih;
45 	struct super_block *sb;
46 	struct erofs_sb_info *sbi;
47 	bool atomic_map;
48 	int ret = 0;
49 
50 	/* the most case is that xattrs of this inode are initialized. */
51 	if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
52 		return 0;
53 
54 	if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE))
55 		return -ERESTARTSYS;
56 
57 	/* someone has initialized xattrs for us? */
58 	if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
59 		goto out_unlock;
60 
61 	/*
62 	 * bypass all xattr operations if ->xattr_isize is not greater than
63 	 * sizeof(struct erofs_xattr_ibody_header), in detail:
64 	 * 1) it is not enough to contain erofs_xattr_ibody_header then
65 	 *    ->xattr_isize should be 0 (it means no xattr);
66 	 * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk
67 	 *    undefined right now (maybe use later with some new sb feature).
68 	 */
69 	if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) {
70 		erofs_err(inode->i_sb,
71 			  "xattr_isize %d of nid %llu is not supported yet",
72 			  vi->xattr_isize, vi->nid);
73 		ret = -EOPNOTSUPP;
74 		goto out_unlock;
75 	} else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) {
76 		if (vi->xattr_isize) {
77 			erofs_err(inode->i_sb,
78 				  "bogus xattr ibody @ nid %llu", vi->nid);
79 			DBG_BUGON(1);
80 			ret = -EFSCORRUPTED;
81 			goto out_unlock;	/* xattr ondisk layout error */
82 		}
83 		ret = -ENOATTR;
84 		goto out_unlock;
85 	}
86 
87 	sb = inode->i_sb;
88 	sbi = EROFS_SB(sb);
89 	it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
90 	it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
91 
92 	it.page = erofs_get_meta_page(sb, it.blkaddr);
93 	if (IS_ERR(it.page)) {
94 		ret = PTR_ERR(it.page);
95 		goto out_unlock;
96 	}
97 
98 	/* read in shared xattr array (non-atomic, see kmalloc below) */
99 	it.kaddr = kmap(it.page);
100 	atomic_map = false;
101 
102 	ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
103 
104 	vi->xattr_shared_count = ih->h_shared_count;
105 	vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
106 						sizeof(uint), GFP_KERNEL);
107 	if (!vi->xattr_shared_xattrs) {
108 		xattr_iter_end(&it, atomic_map);
109 		ret = -ENOMEM;
110 		goto out_unlock;
111 	}
112 
113 	/* let's skip ibody header */
114 	it.ofs += sizeof(struct erofs_xattr_ibody_header);
115 
116 	for (i = 0; i < vi->xattr_shared_count; ++i) {
117 		if (it.ofs >= EROFS_BLKSIZ) {
118 			/* cannot be unaligned */
119 			DBG_BUGON(it.ofs != EROFS_BLKSIZ);
120 			xattr_iter_end(&it, atomic_map);
121 
122 			it.page = erofs_get_meta_page(sb, ++it.blkaddr);
123 			if (IS_ERR(it.page)) {
124 				kfree(vi->xattr_shared_xattrs);
125 				vi->xattr_shared_xattrs = NULL;
126 				ret = PTR_ERR(it.page);
127 				goto out_unlock;
128 			}
129 
130 			it.kaddr = kmap_atomic(it.page);
131 			atomic_map = true;
132 			it.ofs = 0;
133 		}
134 		vi->xattr_shared_xattrs[i] =
135 			le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
136 		it.ofs += sizeof(__le32);
137 	}
138 	xattr_iter_end(&it, atomic_map);
139 
140 	set_bit(EROFS_I_EA_INITED_BIT, &vi->flags);
141 
142 out_unlock:
143 	clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);
144 	return ret;
145 }
146 
147 /*
148  * the general idea for these return values is
149  * if    0 is returned, go on processing the current xattr;
150  *       1 (> 0) is returned, skip this round to process the next xattr;
151  *    -err (< 0) is returned, an error (maybe ENOXATTR) occurred
152  *                            and need to be handled
153  */
154 struct xattr_iter_handlers {
155 	int (*entry)(struct xattr_iter *_it, struct erofs_xattr_entry *entry);
156 	int (*name)(struct xattr_iter *_it, unsigned int processed, char *buf,
157 		    unsigned int len);
158 	int (*alloc_buffer)(struct xattr_iter *_it, unsigned int value_sz);
159 	void (*value)(struct xattr_iter *_it, unsigned int processed, char *buf,
160 		      unsigned int len);
161 };
162 
163 static inline int xattr_iter_fixup(struct xattr_iter *it)
164 {
165 	if (it->ofs < EROFS_BLKSIZ)
166 		return 0;
167 
168 	xattr_iter_end(it, true);
169 
170 	it->blkaddr += erofs_blknr(it->ofs);
171 
172 	it->page = erofs_get_meta_page(it->sb, it->blkaddr);
173 	if (IS_ERR(it->page)) {
174 		int err = PTR_ERR(it->page);
175 
176 		it->page = NULL;
177 		return err;
178 	}
179 
180 	it->kaddr = kmap_atomic(it->page);
181 	it->ofs = erofs_blkoff(it->ofs);
182 	return 0;
183 }
184 
185 static int inline_xattr_iter_begin(struct xattr_iter *it,
186 				   struct inode *inode)
187 {
188 	struct erofs_inode *const vi = EROFS_I(inode);
189 	struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
190 	unsigned int xattr_header_sz, inline_xattr_ofs;
191 
192 	xattr_header_sz = inlinexattr_header_size(inode);
193 	if (xattr_header_sz >= vi->xattr_isize) {
194 		DBG_BUGON(xattr_header_sz > vi->xattr_isize);
195 		return -ENOATTR;
196 	}
197 
198 	inline_xattr_ofs = vi->inode_isize + xattr_header_sz;
199 
200 	it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
201 	it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
202 
203 	it->page = erofs_get_meta_page(inode->i_sb, it->blkaddr);
204 	if (IS_ERR(it->page))
205 		return PTR_ERR(it->page);
206 
207 	it->kaddr = kmap_atomic(it->page);
208 	return vi->xattr_isize - xattr_header_sz;
209 }
210 
211 /*
212  * Regardless of success or failure, `xattr_foreach' will end up with
213  * `ofs' pointing to the next xattr item rather than an arbitrary position.
214  */
215 static int xattr_foreach(struct xattr_iter *it,
216 			 const struct xattr_iter_handlers *op,
217 			 unsigned int *tlimit)
218 {
219 	struct erofs_xattr_entry entry;
220 	unsigned int value_sz, processed, slice;
221 	int err;
222 
223 	/* 0. fixup blkaddr, ofs, ipage */
224 	err = xattr_iter_fixup(it);
225 	if (err)
226 		return err;
227 
228 	/*
229 	 * 1. read xattr entry to the memory,
230 	 *    since we do EROFS_XATTR_ALIGN
231 	 *    therefore entry should be in the page
232 	 */
233 	entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
234 	if (tlimit) {
235 		unsigned int entry_sz = erofs_xattr_entry_size(&entry);
236 
237 		/* xattr on-disk corruption: xattr entry beyond xattr_isize */
238 		if (*tlimit < entry_sz) {
239 			DBG_BUGON(1);
240 			return -EFSCORRUPTED;
241 		}
242 		*tlimit -= entry_sz;
243 	}
244 
245 	it->ofs += sizeof(struct erofs_xattr_entry);
246 	value_sz = le16_to_cpu(entry.e_value_size);
247 
248 	/* handle entry */
249 	err = op->entry(it, &entry);
250 	if (err) {
251 		it->ofs += entry.e_name_len + value_sz;
252 		goto out;
253 	}
254 
255 	/* 2. handle xattr name (ofs will finally be at the end of name) */
256 	processed = 0;
257 
258 	while (processed < entry.e_name_len) {
259 		if (it->ofs >= EROFS_BLKSIZ) {
260 			DBG_BUGON(it->ofs > EROFS_BLKSIZ);
261 
262 			err = xattr_iter_fixup(it);
263 			if (err)
264 				goto out;
265 			it->ofs = 0;
266 		}
267 
268 		slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
269 			      entry.e_name_len - processed);
270 
271 		/* handle name */
272 		err = op->name(it, processed, it->kaddr + it->ofs, slice);
273 		if (err) {
274 			it->ofs += entry.e_name_len - processed + value_sz;
275 			goto out;
276 		}
277 
278 		it->ofs += slice;
279 		processed += slice;
280 	}
281 
282 	/* 3. handle xattr value */
283 	processed = 0;
284 
285 	if (op->alloc_buffer) {
286 		err = op->alloc_buffer(it, value_sz);
287 		if (err) {
288 			it->ofs += value_sz;
289 			goto out;
290 		}
291 	}
292 
293 	while (processed < value_sz) {
294 		if (it->ofs >= EROFS_BLKSIZ) {
295 			DBG_BUGON(it->ofs > EROFS_BLKSIZ);
296 
297 			err = xattr_iter_fixup(it);
298 			if (err)
299 				goto out;
300 			it->ofs = 0;
301 		}
302 
303 		slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
304 			      value_sz - processed);
305 		op->value(it, processed, it->kaddr + it->ofs, slice);
306 		it->ofs += slice;
307 		processed += slice;
308 	}
309 
310 out:
311 	/* xattrs should be 4-byte aligned (on-disk constraint) */
312 	it->ofs = EROFS_XATTR_ALIGN(it->ofs);
313 	return err < 0 ? err : 0;
314 }
315 
316 struct getxattr_iter {
317 	struct xattr_iter it;
318 
319 	char *buffer;
320 	int buffer_size, index;
321 	struct qstr name;
322 };
323 
324 static int xattr_entrymatch(struct xattr_iter *_it,
325 			    struct erofs_xattr_entry *entry)
326 {
327 	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
328 
329 	return (it->index != entry->e_name_index ||
330 		it->name.len != entry->e_name_len) ? -ENOATTR : 0;
331 }
332 
333 static int xattr_namematch(struct xattr_iter *_it,
334 			   unsigned int processed, char *buf, unsigned int len)
335 {
336 	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
337 
338 	return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;
339 }
340 
341 static int xattr_checkbuffer(struct xattr_iter *_it,
342 			     unsigned int value_sz)
343 {
344 	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
345 	int err = it->buffer_size < value_sz ? -ERANGE : 0;
346 
347 	it->buffer_size = value_sz;
348 	return !it->buffer ? 1 : err;
349 }
350 
351 static void xattr_copyvalue(struct xattr_iter *_it,
352 			    unsigned int processed,
353 			    char *buf, unsigned int len)
354 {
355 	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
356 
357 	memcpy(it->buffer + processed, buf, len);
358 }
359 
360 static const struct xattr_iter_handlers find_xattr_handlers = {
361 	.entry = xattr_entrymatch,
362 	.name = xattr_namematch,
363 	.alloc_buffer = xattr_checkbuffer,
364 	.value = xattr_copyvalue
365 };
366 
367 static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
368 {
369 	int ret;
370 	unsigned int remaining;
371 
372 	ret = inline_xattr_iter_begin(&it->it, inode);
373 	if (ret < 0)
374 		return ret;
375 
376 	remaining = ret;
377 	while (remaining) {
378 		ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining);
379 		if (ret != -ENOATTR)
380 			break;
381 	}
382 	xattr_iter_end_final(&it->it);
383 
384 	return ret ? ret : it->buffer_size;
385 }
386 
387 static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
388 {
389 	struct erofs_inode *const vi = EROFS_I(inode);
390 	struct super_block *const sb = inode->i_sb;
391 	struct erofs_sb_info *const sbi = EROFS_SB(sb);
392 	unsigned int i;
393 	int ret = -ENOATTR;
394 
395 	for (i = 0; i < vi->xattr_shared_count; ++i) {
396 		erofs_blk_t blkaddr =
397 			xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
398 
399 		it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
400 
401 		if (!i || blkaddr != it->it.blkaddr) {
402 			if (i)
403 				xattr_iter_end(&it->it, true);
404 
405 			it->it.page = erofs_get_meta_page(sb, blkaddr);
406 			if (IS_ERR(it->it.page))
407 				return PTR_ERR(it->it.page);
408 
409 			it->it.kaddr = kmap_atomic(it->it.page);
410 			it->it.blkaddr = blkaddr;
411 		}
412 
413 		ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL);
414 		if (ret != -ENOATTR)
415 			break;
416 	}
417 	if (vi->xattr_shared_count)
418 		xattr_iter_end_final(&it->it);
419 
420 	return ret ? ret : it->buffer_size;
421 }
422 
423 static bool erofs_xattr_user_list(struct dentry *dentry)
424 {
425 	return test_opt(EROFS_SB(dentry->d_sb), XATTR_USER);
426 }
427 
428 static bool erofs_xattr_trusted_list(struct dentry *dentry)
429 {
430 	return capable(CAP_SYS_ADMIN);
431 }
432 
433 int erofs_getxattr(struct inode *inode, int index,
434 		   const char *name,
435 		   void *buffer, size_t buffer_size)
436 {
437 	int ret;
438 	struct getxattr_iter it;
439 
440 	if (!name)
441 		return -EINVAL;
442 
443 	ret = init_inode_xattrs(inode);
444 	if (ret)
445 		return ret;
446 
447 	it.index = index;
448 
449 	it.name.len = strlen(name);
450 	if (it.name.len > EROFS_NAME_LEN)
451 		return -ERANGE;
452 	it.name.name = name;
453 
454 	it.buffer = buffer;
455 	it.buffer_size = buffer_size;
456 
457 	it.it.sb = inode->i_sb;
458 	ret = inline_getxattr(inode, &it);
459 	if (ret == -ENOATTR)
460 		ret = shared_getxattr(inode, &it);
461 	return ret;
462 }
463 
464 static int erofs_xattr_generic_get(const struct xattr_handler *handler,
465 				   struct dentry *unused, struct inode *inode,
466 				   const char *name, void *buffer, size_t size)
467 {
468 	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
469 
470 	switch (handler->flags) {
471 	case EROFS_XATTR_INDEX_USER:
472 		if (!test_opt(sbi, XATTR_USER))
473 			return -EOPNOTSUPP;
474 		break;
475 	case EROFS_XATTR_INDEX_TRUSTED:
476 		if (!capable(CAP_SYS_ADMIN))
477 			return -EPERM;
478 		break;
479 	case EROFS_XATTR_INDEX_SECURITY:
480 		break;
481 	default:
482 		return -EINVAL;
483 	}
484 
485 	return erofs_getxattr(inode, handler->flags, name, buffer, size);
486 }
487 
488 const struct xattr_handler erofs_xattr_user_handler = {
489 	.prefix	= XATTR_USER_PREFIX,
490 	.flags	= EROFS_XATTR_INDEX_USER,
491 	.list	= erofs_xattr_user_list,
492 	.get	= erofs_xattr_generic_get,
493 };
494 
495 const struct xattr_handler erofs_xattr_trusted_handler = {
496 	.prefix	= XATTR_TRUSTED_PREFIX,
497 	.flags	= EROFS_XATTR_INDEX_TRUSTED,
498 	.list	= erofs_xattr_trusted_list,
499 	.get	= erofs_xattr_generic_get,
500 };
501 
502 #ifdef CONFIG_EROFS_FS_SECURITY
503 const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
504 	.prefix	= XATTR_SECURITY_PREFIX,
505 	.flags	= EROFS_XATTR_INDEX_SECURITY,
506 	.get	= erofs_xattr_generic_get,
507 };
508 #endif
509 
510 const struct xattr_handler *erofs_xattr_handlers[] = {
511 	&erofs_xattr_user_handler,
512 #ifdef CONFIG_EROFS_FS_POSIX_ACL
513 	&posix_acl_access_xattr_handler,
514 	&posix_acl_default_xattr_handler,
515 #endif
516 	&erofs_xattr_trusted_handler,
517 #ifdef CONFIG_EROFS_FS_SECURITY
518 	&erofs_xattr_security_handler,
519 #endif
520 	NULL,
521 };
522 
523 struct listxattr_iter {
524 	struct xattr_iter it;
525 
526 	struct dentry *dentry;
527 	char *buffer;
528 	int buffer_size, buffer_ofs;
529 };
530 
531 static int xattr_entrylist(struct xattr_iter *_it,
532 			   struct erofs_xattr_entry *entry)
533 {
534 	struct listxattr_iter *it =
535 		container_of(_it, struct listxattr_iter, it);
536 	unsigned int prefix_len;
537 	const char *prefix;
538 
539 	const struct xattr_handler *h =
540 		erofs_xattr_handler(entry->e_name_index);
541 
542 	if (!h || (h->list && !h->list(it->dentry)))
543 		return 1;
544 
545 	prefix = xattr_prefix(h);
546 	prefix_len = strlen(prefix);
547 
548 	if (!it->buffer) {
549 		it->buffer_ofs += prefix_len + entry->e_name_len + 1;
550 		return 1;
551 	}
552 
553 	if (it->buffer_ofs + prefix_len
554 		+ entry->e_name_len + 1 > it->buffer_size)
555 		return -ERANGE;
556 
557 	memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
558 	it->buffer_ofs += prefix_len;
559 	return 0;
560 }
561 
562 static int xattr_namelist(struct xattr_iter *_it,
563 			  unsigned int processed, char *buf, unsigned int len)
564 {
565 	struct listxattr_iter *it =
566 		container_of(_it, struct listxattr_iter, it);
567 
568 	memcpy(it->buffer + it->buffer_ofs, buf, len);
569 	it->buffer_ofs += len;
570 	return 0;
571 }
572 
573 static int xattr_skipvalue(struct xattr_iter *_it,
574 			   unsigned int value_sz)
575 {
576 	struct listxattr_iter *it =
577 		container_of(_it, struct listxattr_iter, it);
578 
579 	it->buffer[it->buffer_ofs++] = '\0';
580 	return 1;
581 }
582 
583 static const struct xattr_iter_handlers list_xattr_handlers = {
584 	.entry = xattr_entrylist,
585 	.name = xattr_namelist,
586 	.alloc_buffer = xattr_skipvalue,
587 	.value = NULL
588 };
589 
590 static int inline_listxattr(struct listxattr_iter *it)
591 {
592 	int ret;
593 	unsigned int remaining;
594 
595 	ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry));
596 	if (ret < 0)
597 		return ret;
598 
599 	remaining = ret;
600 	while (remaining) {
601 		ret = xattr_foreach(&it->it, &list_xattr_handlers, &remaining);
602 		if (ret)
603 			break;
604 	}
605 	xattr_iter_end_final(&it->it);
606 	return ret ? ret : it->buffer_ofs;
607 }
608 
609 static int shared_listxattr(struct listxattr_iter *it)
610 {
611 	struct inode *const inode = d_inode(it->dentry);
612 	struct erofs_inode *const vi = EROFS_I(inode);
613 	struct super_block *const sb = inode->i_sb;
614 	struct erofs_sb_info *const sbi = EROFS_SB(sb);
615 	unsigned int i;
616 	int ret = 0;
617 
618 	for (i = 0; i < vi->xattr_shared_count; ++i) {
619 		erofs_blk_t blkaddr =
620 			xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
621 
622 		it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
623 		if (!i || blkaddr != it->it.blkaddr) {
624 			if (i)
625 				xattr_iter_end(&it->it, true);
626 
627 			it->it.page = erofs_get_meta_page(sb, blkaddr);
628 			if (IS_ERR(it->it.page))
629 				return PTR_ERR(it->it.page);
630 
631 			it->it.kaddr = kmap_atomic(it->it.page);
632 			it->it.blkaddr = blkaddr;
633 		}
634 
635 		ret = xattr_foreach(&it->it, &list_xattr_handlers, NULL);
636 		if (ret)
637 			break;
638 	}
639 	if (vi->xattr_shared_count)
640 		xattr_iter_end_final(&it->it);
641 
642 	return ret ? ret : it->buffer_ofs;
643 }
644 
645 ssize_t erofs_listxattr(struct dentry *dentry,
646 			char *buffer, size_t buffer_size)
647 {
648 	int ret;
649 	struct listxattr_iter it;
650 
651 	ret = init_inode_xattrs(d_inode(dentry));
652 	if (ret)
653 		return ret;
654 
655 	it.dentry = dentry;
656 	it.buffer = buffer;
657 	it.buffer_size = buffer_size;
658 	it.buffer_ofs = 0;
659 
660 	it.it.sb = dentry->d_sb;
661 
662 	ret = inline_listxattr(&it);
663 	if (ret < 0 && ret != -ENOATTR)
664 		return ret;
665 	return shared_listxattr(&it);
666 }
667 
668 #ifdef CONFIG_EROFS_FS_POSIX_ACL
669 struct posix_acl *erofs_get_acl(struct inode *inode, int type)
670 {
671 	struct posix_acl *acl;
672 	int prefix, rc;
673 	char *value = NULL;
674 
675 	switch (type) {
676 	case ACL_TYPE_ACCESS:
677 		prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
678 		break;
679 	case ACL_TYPE_DEFAULT:
680 		prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
681 		break;
682 	default:
683 		return ERR_PTR(-EINVAL);
684 	}
685 
686 	rc = erofs_getxattr(inode, prefix, "", NULL, 0);
687 	if (rc > 0) {
688 		value = kmalloc(rc, GFP_KERNEL);
689 		if (!value)
690 			return ERR_PTR(-ENOMEM);
691 		rc = erofs_getxattr(inode, prefix, "", value, rc);
692 	}
693 
694 	if (rc == -ENOATTR)
695 		acl = NULL;
696 	else if (rc < 0)
697 		acl = ERR_PTR(rc);
698 	else
699 		acl = posix_acl_from_xattr(&init_user_ns, value, rc);
700 	kfree(value);
701 	return acl;
702 }
703 #endif
704 
705