1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License version 2 as
4  * published by the Free Software Foundation.
5  *
6  * This program is distributed in the hope that it will be useful,
7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
9  * GNU General Public License for more details.
10  *
11  * You should have received a copy of the GNU General Public Licens
12  * along with this program; if not, write to the Free Software
13  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
14  */
15 
16 #include <ext2fs.h>
17 #include <linux/module.h>
18 #include <linux/ext4_xattr.h>
19 
20 static ext4_fsblk_t ext4_new_meta_blocks(void *icb, struct inode *inode,
21 	ext4_fsblk_t goal,
22 	unsigned int flags,
23 	unsigned long *count, int *errp)
24 {
25 	NTSTATUS status;
26 	ULONG blockcnt = (count) ? *count : 1;
27 	ULONG block = 0;
28 
29 	status = Ext2NewBlock((PEXT2_IRP_CONTEXT)icb,
30 		inode->i_sb->s_priv,
31 		0, (ULONG)goal,
32 		&block,
33 		&blockcnt);
34 	if (count)
35 		*count = blockcnt;
36 
37 	if (!NT_SUCCESS(status)) {
38 		*errp = Ext2LinuxError(status);
39 		return 0;
40 	}
41 	inode->i_blocks += (blockcnt * (inode->i_sb->s_blocksize >> 9));
42 	return block;
43 }
44 
45 static void ext4_free_blocks(void *icb, struct inode *inode,
46 	ext4_fsblk_t block, int count, int flags)
47 {
48 	Ext2FreeBlock((PEXT2_IRP_CONTEXT)icb, inode->i_sb->s_priv, (ULONG)block, count);
49 	inode->i_blocks -= count * (inode->i_sb->s_blocksize >> 9);
50 	return;
51 }
52 
53 static inline ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
54 {
55 	PEXT2_VCB Vcb;
56 	Vcb = inode->i_sb->s_priv;
57 	return (inode->i_ino - 1) / BLOCKS_PER_GROUP;
58 }
59 
60 #define NAME_HASH_SHIFT 5
61 #define VALUE_HASH_SHIFT 16
62 
63 static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
64 					   struct ext4_xattr_entry *entry)
65 {
66 	__u32 hash = 0;
67 	char *name = EXT4_XATTR_NAME(entry);
68 	int n;
69 
70 	for (n = 0; n < entry->e_name_len; n++) {
71 		hash = (hash << NAME_HASH_SHIFT) ^
72 		       (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
73 	}
74 
75 	if (entry->e_value_block == 0 && entry->e_value_size != 0) {
76 		__le32 *value =
77 		    (__le32 *)((char *)header + le16_to_cpu(entry->e_value_offs));
78 		for (n = (le32_to_cpu(entry->e_value_size) + EXT4_XATTR_ROUND) >>
79 			 EXT4_XATTR_PAD_BITS;
80 		     n; n--) {
81 			hash = (hash << VALUE_HASH_SHIFT) ^
82 			       (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
83 			       le32_to_cpu(*value++);
84 		}
85 	}
86 	entry->e_hash = cpu_to_le32(hash);
87 }
88 
89 #define BLOCK_HASH_SHIFT 16
90 
91 /*
92  * ext4_xattr_rehash()
93  *
94  * Re-compute the extended attribute hash value after an entry has changed.
95  */
96 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
97 			      struct ext4_xattr_entry *entry)
98 {
99 	struct ext4_xattr_entry *here;
100 	__u32 hash = 0;
101 
102 	ext4_xattr_compute_hash(header, entry);
103 	here = EXT4_XATTR_ENTRY(header + 1);
104 	while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
105 		if (!here->e_hash) {
106 			/* Block is not shared if an entry's hash value == 0 */
107 			hash = 0;
108 			break;
109 		}
110 		hash = (hash << BLOCK_HASH_SHIFT) ^
111 		       (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
112 		       le32_to_cpu(here->e_hash);
113 		here = EXT4_XATTR_NEXT(here);
114 	}
115 	header->h_hash = cpu_to_le32(hash);
116 }
117 
118 #if CONFIG_META_CSUM_ENABLE
119 static __u32
120 ext4_xattr_block_checksum(PEXT2_MCB inode_ref,
121 			  ext4_fsblk_t blocknr,
122 			  struct ext4_xattr_header *header)
123 {
124 	__u32 checksum = 0;
125 	__u64 le64_blocknr = blocknr;
126 	struct ext4_sblock *sb = &inode_ref->fs->sb;
127 
128 	if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
129 		__u32 orig_checksum;
130 
131 		/* Preparation: temporarily set bg checksum to 0 */
132 		orig_checksum = header->h_checksum;
133 		header->h_checksum = 0;
134 		/* First calculate crc32 checksum against fs uuid */
135 		checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
136 				sizeof(sb->uuid));
137 		/* Then calculate crc32 checksum block number */
138 		checksum = ext4_crc32c(checksum, &le64_blocknr,
139 				     sizeof(le64_blocknr));
140 		/* Finally calculate crc32 checksum against
141 		 * the entire xattr block */
142 		checksum = ext4_crc32c(checksum, header,
143 				   ext4_sb_get_block_size(sb));
144 		header->h_checksum = orig_checksum;
145 	}
146 	return checksum;
147 }
148 #else
149 #define ext4_xattr_block_checksum(...) 0
150 #endif
151 
152 static void
153 ext4_xattr_set_block_checksum(PEXT2_MCB inode_ref,
154 			      ext4_fsblk_t blocknr,
155 			      struct ext4_xattr_header *header)
156 {
157 	/* TODO: Need METADATA_CSUM supports. */
158 	header->h_checksum = 0;
159 }
160 
161 static int ext4_xattr_item_cmp(struct rb_node *_a,
162 			       struct rb_node *_b)
163 {
164 	int result;
165 	struct ext4_xattr_item *a, *b;
166 	a = container_of(_a, struct ext4_xattr_item, node);
167 	a = container_of(_a, struct ext4_xattr_item, node);
168 	b = container_of(_b, struct ext4_xattr_item, node);
169 
170 	if (a->is_data && !b->is_data)
171 		return -1;
172 
173 	if (!a->is_data && b->is_data)
174 		return 1;
175 
176 	result = a->name_index - b->name_index;
177 	if (result)
178 		return result;
179 
180 	if (a->name_len < b->name_len)
181 		return -1;
182 
183 	if (a->name_len > b->name_len)
184 		return 1;
185 
186 	return memcmp(a->name, b->name, a->name_len);
187 }
188 
189 //
190 // Red-black tree insert routine.
191 //
192 
193 static struct ext4_xattr_item *
194 ext4_xattr_item_search(struct ext4_xattr_ref *xattr_ref,
195 		       struct ext4_xattr_item *name)
196 {
197 	struct rb_node *new = xattr_ref->root.rb_node;
198 
199 	while (new) {
200 		struct ext4_xattr_item *node =
201 			container_of(new, struct ext4_xattr_item, node);
202 		int result = ext4_xattr_item_cmp(&name->node, new);
203 
204 		if (result < 0)
205 			new = new->rb_left;
206 		else if (result > 0)
207 			new = new->rb_right;
208 		else
209 			return node;
210 
211 	}
212 
213 	return NULL;
214 }
215 
216 static void ext4_xattr_item_insert(struct ext4_xattr_ref *xattr_ref,
217 				   struct ext4_xattr_item *item)
218 {
219 	rb_insert(&xattr_ref->root, &item->node,
220 	      ext4_xattr_item_cmp);
221 	list_add_tail(&item->list_node, &xattr_ref->ordered_list);
222 }
223 
224 static void ext4_xattr_item_remove(struct ext4_xattr_ref *xattr_ref,
225 				   struct ext4_xattr_item *item)
226 {
227 	rb_erase(&item->node, &xattr_ref->root);
228 	list_del_init(&item->list_node);
229 }
230 
231 static struct ext4_xattr_item *
232 ext4_xattr_item_alloc(__u8 name_index, const char *name, size_t name_len)
233 {
234 	struct ext4_xattr_item *item;
235 	item = kzalloc(sizeof(struct ext4_xattr_item) + name_len, GFP_NOFS);
236 	if (!item)
237 		return NULL;
238 
239 	item->name_index = name_index;
240 	item->name = (char *)(item + 1);
241 	item->name_len = name_len;
242 	item->data = NULL;
243 	item->data_size = 0;
244 	INIT_LIST_HEAD(&item->list_node);
245 
246 	memcpy(item->name, name, name_len);
247 
248 	if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
249 	    name_len == 4 &&
250 	    !memcmp(name, "data", 4))
251 		item->is_data = TRUE;
252 	else
253 		item->is_data = FALSE;
254 
255 	return item;
256 }
257 
258 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
259 				      const void *orig_data, size_t data_size)
260 {
261 	void *data = NULL;
262 	ASSERT(!item->data);
263 	data = kmalloc(data_size, GFP_NOFS);
264 	if (!data)
265 		return -ENOMEM;
266 
267 	if (orig_data)
268 		memcpy(data, orig_data, data_size);
269 
270 	item->data = data;
271 	item->data_size = data_size;
272 	return 0;
273 }
274 
275 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
276 {
277 	ASSERT(item->data);
278 	kfree(item->data);
279 	item->data = NULL;
280 	item->data_size = 0;
281 }
282 
283 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
284 				       size_t new_data_size)
285 {
286 	if (new_data_size != item->data_size) {
287 		void *new_data;
288 		new_data = kmalloc(new_data_size, GFP_NOFS);
289 		if (!new_data)
290 			return -ENOMEM;
291 
292 		memcpy(new_data, item->data, item->data_size);
293 		kfree(item->data);
294 
295 		item->data = new_data;
296 		item->data_size = new_data_size;
297 	}
298 	return 0;
299 }
300 
301 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
302 {
303 	if (item->data)
304 		ext4_xattr_item_free_data(item);
305 
306 	kfree(item);
307 }
308 
309 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
310 				   struct ext4_xattr_entry *entry,
311 				   BOOL in_inode)
312 {
313 	char *ret;
314 	int block_size;
315 	if (in_inode) {
316 		struct ext4_xattr_ibody_header *header;
317 		struct ext4_xattr_entry *first_entry;
318 		int inode_size = xattr_ref->fs->InodeSize;
319 		header = EXT4_XATTR_IHDR(xattr_ref->OnDiskInode);
320 		first_entry = EXT4_XATTR_IFIRST(header);
321 
322 		ret = ((char *)first_entry + le16_to_cpu(entry->e_value_offs));
323 		if (ret + EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size)) -
324 			(char *)xattr_ref->OnDiskInode > inode_size)
325 			ret = NULL;
326 
327 		return ret;
328 
329 	}
330 	block_size = xattr_ref->fs->BlockSize;
331 	ret = ((char *)xattr_ref->block_bh->b_data + le16_to_cpu(entry->e_value_offs));
332 	if (ret + EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size)) -
333 			(char *)xattr_ref->block_bh->b_data > block_size)
334 		ret = NULL;
335 	return ret;
336 }
337 
338 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
339 {
340 	int ret = 0;
341 	size_t size_rem;
342 	void *data;
343 	struct ext4_xattr_entry *entry = NULL;
344 
345 	ASSERT(xattr_ref->block_bh->b_data);
346 	entry = EXT4_XATTR_BFIRST(xattr_ref->block_bh);
347 
348 	size_rem = xattr_ref->fs->BlockSize;
349 	for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
350 	     entry = EXT4_XATTR_NEXT(entry),
351 	     size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
352 		struct ext4_xattr_item *item;
353 		char *e_name = EXT4_XATTR_NAME(entry);
354 
355 		data = ext4_xattr_entry_data(xattr_ref, entry, FALSE);
356 		if (!data) {
357 			ret = -EIO;
358 			goto Finish;
359 		}
360 
361 		item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
362 					     (size_t)entry->e_name_len);
363 		if (!item) {
364 			ret = -ENOMEM;
365 			goto Finish;
366 		}
367 		if (ext4_xattr_item_alloc_data(
368 			item, data, le32_to_cpu(entry->e_value_size)) != 0) {
369 			ext4_xattr_item_free(item);
370 			ret = -ENOMEM;
371 			goto Finish;
372 		}
373 		ext4_xattr_item_insert(xattr_ref, item);
374 		xattr_ref->block_size_rem -=
375 			EXT4_XATTR_SIZE(item->data_size) +
376 			EXT4_XATTR_LEN(item->name_len);
377 		xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
378 				      EXT4_XATTR_LEN(item->name_len);
379 	}
380 
381 Finish:
382 	return ret;
383 }
384 
385 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
386 {
387 	void *data;
388 	size_t size_rem;
389 	int ret = 0;
390 	struct ext4_xattr_ibody_header *header = NULL;
391 	struct ext4_xattr_entry *entry = NULL;
392 	int inode_size = xattr_ref->fs->InodeSize;
393 
394 	header = EXT4_XATTR_IHDR(xattr_ref->OnDiskInode);
395 	entry = EXT4_XATTR_IFIRST(header);
396 
397 	size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
398 		   xattr_ref->OnDiskInode->i_extra_isize;
399 	for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
400 	     entry = EXT4_XATTR_NEXT(entry),
401 	     size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
402 		struct ext4_xattr_item *item;
403 		char *e_name = EXT4_XATTR_NAME(entry);
404 
405 		data = ext4_xattr_entry_data(xattr_ref, entry, TRUE);
406 		if (!data) {
407 			ret = -EIO;
408 			goto Finish;
409 		}
410 
411 		item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
412 					     (size_t)entry->e_name_len);
413 		if (!item) {
414 			ret = -ENOMEM;
415 			goto Finish;
416 		}
417 		if (ext4_xattr_item_alloc_data(
418 			item, data, le32_to_cpu(entry->e_value_size)) != 0) {
419 			ext4_xattr_item_free(item);
420 			ret = -ENOMEM;
421 			goto Finish;
422 		}
423 		item->in_inode = TRUE;
424 		ext4_xattr_item_insert(xattr_ref, item);
425 		xattr_ref->inode_size_rem -=
426 			EXT4_XATTR_SIZE(item->data_size) +
427 			EXT4_XATTR_LEN(item->name_len);
428 		xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
429 				      EXT4_XATTR_LEN(item->name_len);
430 	}
431 
432 Finish:
433 	return ret;
434 }
435 
436 static __s32 ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
437 {
438 	int inode_size = xattr_ref->fs->InodeSize;
439 	int size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
440 			    xattr_ref->OnDiskInode->i_extra_isize;
441 	return size_rem;
442 }
443 
444 static __s32 ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
445 {
446 	return xattr_ref->fs->BlockSize;
447 }
448 
449 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
450 {
451 	int ret = 0;
452 	int inode_size = xattr_ref->fs->InodeSize;
453 	if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
454 		ret = ext4_xattr_inode_fetch(xattr_ref);
455 		if (ret != 0)
456 			return ret;
457 	}
458 
459 	if (xattr_ref->block_loaded)
460 		ret = ext4_xattr_block_fetch(xattr_ref);
461 
462 	xattr_ref->dirty = FALSE;
463 	return ret;
464 }
465 
466 static struct ext4_xattr_item *
467 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, __u8 name_index,
468 		       const char *name, size_t name_len)
469 {
470 	struct ext4_xattr_item tmp = {
471 		FALSE,
472 		FALSE,
473 		name_index,
474 		(char *)name, /*won't touch this string*/
475 		name_len,
476 	};
477 	if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
478 	    name_len == 4 &&
479 	    !memcmp(name, "data", 4))
480 		tmp.is_data = TRUE;
481 
482 	return ext4_xattr_item_search(xattr_ref, &tmp);
483 }
484 
485 static struct ext4_xattr_item *
486 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, __u8 name_index,
487 		       const char *name, size_t name_len, const void *data,
488 		       size_t data_size,
489 		       int *err)
490 {
491 	struct ext4_xattr_item *item;
492 	item = ext4_xattr_item_alloc(name_index, name, name_len);
493 	if (!item) {
494 		if (err)
495 			*err = -ENOMEM;
496 
497 		return NULL;
498 	}
499 
500 	item->in_inode = TRUE;
501 	if (xattr_ref->inode_size_rem <
502 	   EXT4_XATTR_SIZE(data_size) +
503 	   EXT4_XATTR_LEN(item->name_len)) {
504 		if (xattr_ref->block_size_rem <
505 		   EXT4_XATTR_SIZE(data_size) +
506 		   EXT4_XATTR_LEN(item->name_len)) {
507 			if (err)
508 				*err = -ENOSPC;
509 
510 			return NULL;
511 		}
512 
513 		item->in_inode = FALSE;
514 	}
515 	if (ext4_xattr_item_alloc_data(item, data, data_size) != 0) {
516 		ext4_xattr_item_free(item);
517 		if (err)
518 			*err = -ENOMEM;
519 
520 		return NULL;
521 	}
522 	ext4_xattr_item_insert(xattr_ref, item);
523 	xattr_ref->ea_size +=
524 	    EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
525 	if (item->in_inode) {
526 		xattr_ref->inode_size_rem -=
527 			EXT4_XATTR_SIZE(item->data_size) +
528 			EXT4_XATTR_LEN(item->name_len);
529 	} else {
530 		xattr_ref->block_size_rem -=
531 			EXT4_XATTR_SIZE(item->data_size) +
532 			EXT4_XATTR_LEN(item->name_len);
533 	}
534 	xattr_ref->dirty = TRUE;
535 	if (err)
536 		*err = 0;
537 
538 	return item;
539 }
540 
541 static struct ext4_xattr_item *
542 ext4_xattr_insert_item_ordered(struct ext4_xattr_ref *xattr_ref, __u8 name_index,
543 	const char *name, size_t name_len, const void *data,
544 	size_t data_size,
545 	int *err)
546 {
547 	struct ext4_xattr_item *item, *last_item = NULL;
548 	item = ext4_xattr_item_alloc(name_index, name, name_len);
549 	if (!item) {
550 		if (err)
551 			*err = -ENOMEM;
552 
553 		return NULL;
554 	}
555 
556 	if (!list_empty(&xattr_ref->ordered_list))
557 		last_item = list_entry(xattr_ref->ordered_list.prev,
558 					struct ext4_xattr_item,
559 					list_node);
560 
561 	item->in_inode = TRUE;
562 	if ((xattr_ref->inode_size_rem <
563 		EXT4_XATTR_SIZE(data_size) +
564 		EXT4_XATTR_LEN(item->name_len))
565 			||
566 		(last_item && !last_item->in_inode)) {
567 		if (xattr_ref->block_size_rem <
568 			EXT4_XATTR_SIZE(data_size) +
569 			EXT4_XATTR_LEN(item->name_len)) {
570 			if (err)
571 				*err = -ENOSPC;
572 
573 			return NULL;
574 		}
575 
576 		item->in_inode = FALSE;
577 	}
578 	if (ext4_xattr_item_alloc_data(item, data, data_size) != 0) {
579 		ext4_xattr_item_free(item);
580 		if (err)
581 			*err = -ENOMEM;
582 
583 		return NULL;
584 	}
585 	ext4_xattr_item_insert(xattr_ref, item);
586 	xattr_ref->ea_size +=
587 		EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
588 	if (item->in_inode) {
589 		xattr_ref->inode_size_rem -=
590 			EXT4_XATTR_SIZE(item->data_size) +
591 			EXT4_XATTR_LEN(item->name_len);
592 	}
593 	else {
594 		xattr_ref->block_size_rem -=
595 			EXT4_XATTR_SIZE(item->data_size) +
596 			EXT4_XATTR_LEN(item->name_len);
597 	}
598 	xattr_ref->dirty = TRUE;
599 	if (err)
600 		*err = 0;
601 
602 	return item;
603 }
604 
605 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
606 				  __u8 name_index, const char *name,
607 				  size_t name_len)
608 {
609 	int ret = -ENOENT;
610 	struct ext4_xattr_item *item =
611 	    ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
612 	if (item) {
613 		if (item == xattr_ref->iter_from) {
614 			struct rb_node *next_node;
615 			next_node = rb_next(&item->node);
616 			if (next_node)
617 				xattr_ref->iter_from =
618 					container_of(next_node,
619 						     struct ext4_xattr_item,
620 						     node);
621 			else
622 				xattr_ref->iter_from = NULL;
623 		}
624 
625 		xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
626 				      EXT4_XATTR_LEN(item->name_len);
627 
628 		if (item->in_inode) {
629 			xattr_ref->inode_size_rem +=
630 				EXT4_XATTR_SIZE(item->data_size) +
631 				EXT4_XATTR_LEN(item->name_len);
632 		} else {
633 			xattr_ref->block_size_rem +=
634 				EXT4_XATTR_SIZE(item->data_size) +
635 				EXT4_XATTR_LEN(item->name_len);
636 		}
637 
638 		ext4_xattr_item_remove(xattr_ref, item);
639 		ext4_xattr_item_free(item);
640 		xattr_ref->dirty = TRUE;
641 		ret = 0;
642 	}
643 	return ret;
644 }
645 
646 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
647 				  struct ext4_xattr_item *item,
648 				  size_t new_data_size)
649 {
650 	int ret = 0;
651 	BOOL to_inode = FALSE, to_block = FALSE;
652 	size_t old_data_size = item->data_size;
653 	size_t orig_room_size = item->in_inode ?
654 		xattr_ref->inode_size_rem :
655 		xattr_ref->block_size_rem;
656 
657 	/*
658 	 * Check if we can hold this entry in both in-inode and
659 	 * on-block form
660 	 *
661 	 * More complicated case: we do not allow entries stucking in
662 	 * the middle between in-inode space and on-block space, so
663 	 * the entry has to stay in either inode space or block space.
664 	 */
665 	if (item->in_inode) {
666 		if (xattr_ref->inode_size_rem +
667 			       EXT4_XATTR_SIZE(old_data_size) <
668 			       EXT4_XATTR_SIZE(new_data_size)) {
669 			if (xattr_ref->block_size_rem <
670 				       EXT4_XATTR_SIZE(new_data_size) +
671 				       EXT4_XATTR_LEN(item->name_len))
672 				return -ENOSPC;
673 
674 			to_block = TRUE;
675 		}
676 	} else {
677 		if (xattr_ref->block_size_rem +
678 				EXT4_XATTR_SIZE(old_data_size) <
679 				EXT4_XATTR_SIZE(new_data_size)) {
680 			if (xattr_ref->inode_size_rem <
681 					EXT4_XATTR_SIZE(new_data_size) +
682 					EXT4_XATTR_LEN(item->name_len))
683 				return -ENOSPC;
684 
685 			to_inode = TRUE;
686 		}
687 	}
688 	ret = ext4_xattr_item_resize_data(item, new_data_size);
689 	if (ret)
690 		return ret;
691 
692 	xattr_ref->ea_size =
693 	    xattr_ref->ea_size -
694 	    EXT4_XATTR_SIZE(old_data_size) +
695 	    EXT4_XATTR_SIZE(new_data_size);
696 
697 	/*
698 	 * This entry may originally lie in inode space or block space,
699 	 * and it is going to be transferred to another place.
700 	 */
701 	if (to_block) {
702 		xattr_ref->inode_size_rem +=
703 			EXT4_XATTR_SIZE(old_data_size) +
704 			EXT4_XATTR_LEN(item->name_len);
705 		xattr_ref->block_size_rem -=
706 			EXT4_XATTR_SIZE(new_data_size) +
707 			EXT4_XATTR_LEN(item->name_len);
708 		item->in_inode = FALSE;
709 	} else if (to_inode) {
710 		xattr_ref->block_size_rem +=
711 			EXT4_XATTR_SIZE(old_data_size) +
712 			EXT4_XATTR_LEN(item->name_len);
713 		xattr_ref->inode_size_rem -=
714 			EXT4_XATTR_SIZE(new_data_size) +
715 			EXT4_XATTR_LEN(item->name_len);
716 		item->in_inode = TRUE;
717 	} else {
718 		/*
719 		 * No need to transfer as there is enough space for the entry
720 		 * to stay in inode space or block space it used to be.
721 		 */
722 		orig_room_size +=
723 			EXT4_XATTR_SIZE(old_data_size);
724 		orig_room_size -=
725 			EXT4_XATTR_SIZE(new_data_size);
726 		if (item->in_inode)
727 			xattr_ref->inode_size_rem = orig_room_size;
728 		else
729 			xattr_ref->block_size_rem = orig_room_size;
730 
731 	}
732 	xattr_ref->dirty = TRUE;
733 	return ret;
734 }
735 
736 void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
737 {
738 	struct rb_node *first_node;
739 	struct ext4_xattr_item *item = NULL;
740 	first_node = rb_first(&xattr_ref->root);
741 	if (first_node)
742 		item = container_of(first_node, struct ext4_xattr_item,
743 				    node);
744 
745 	while (item) {
746 		struct rb_node *next_node;
747 		struct ext4_xattr_item *next_item = NULL;
748 		next_node = rb_next(&item->node);
749 		if (next_node)
750 			next_item = container_of(next_node, struct ext4_xattr_item,
751 						 node);
752 		else
753 			next_item = NULL;
754 
755 		ext4_xattr_item_remove(xattr_ref, item);
756 		ext4_xattr_item_free(item);
757 
758 		item = next_item;
759 	}
760 	xattr_ref->ea_size = 0;
761 	if (ext4_xattr_inode_space(xattr_ref) <
762 	   sizeof(struct ext4_xattr_ibody_header))
763 		xattr_ref->inode_size_rem = 0;
764 	else
765 		xattr_ref->inode_size_rem =
766 		       ext4_xattr_inode_space(xattr_ref) -
767 		       sizeof(struct ext4_xattr_ibody_header);
768 
769 	xattr_ref->block_size_rem =
770 		ext4_xattr_block_space(xattr_ref) -
771 		sizeof(struct ext4_xattr_header);
772 }
773 
774 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
775 {
776 	int ret = 0;
777 
778 	ext4_fsblk_t xattr_block = 0;
779 	xattr_block = xattr_ref->inode_ref->Inode.i_file_acl;
780 	if (!xattr_block) {
781 		ext4_fsblk_t goal =
782 			ext4_inode_to_goal_block(&xattr_ref->inode_ref->Inode);
783 
784 		xattr_block = ext4_new_meta_blocks(xattr_ref->IrpContext,
785 						  &xattr_ref->inode_ref->Inode,
786 					      goal, 0, NULL,
787 					      &ret);
788 		if (ret != 0)
789 			goto Finish;
790 
791 		xattr_ref->block_bh = extents_bwrite(&xattr_ref->fs->sb, xattr_block);
792 		if (!xattr_ref->block_bh) {
793 			ext4_free_blocks(xattr_ref->IrpContext, &xattr_ref->inode_ref->Inode,
794 					       xattr_block, 1, 0);
795 			ret = -ENOMEM;
796 			goto Finish;
797 		}
798 
799 		xattr_ref->inode_ref->Inode.i_file_acl = xattr_block;
800 		xattr_ref->IsOnDiskInodeDirty = TRUE;
801 		xattr_ref->block_loaded = TRUE;
802 	}
803 
804 Finish:
805 	return ret;
806 }
807 
808 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
809 {
810 	ext4_fsblk_t xattr_block;
811 	xattr_block = xattr_ref->inode_ref->Inode.i_file_acl;
812 	xattr_ref->inode_ref->Inode.i_file_acl = 0;
813 	extents_brelse(xattr_ref->block_bh);
814 	xattr_ref->block_bh = NULL;
815 	ext4_free_blocks(xattr_ref->IrpContext, &xattr_ref->inode_ref->Inode,
816 		xattr_block, 1, 0);
817 	xattr_ref->IsOnDiskInodeDirty = TRUE;
818 	xattr_ref->block_loaded = FALSE;
819 }
820 
821 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
822 {
823 	struct ext4_xattr_header *block_header = NULL;
824 	block_header = EXT4_XATTR_BHDR(xattr_ref->block_bh);
825 
826 	memset(block_header, 0, sizeof(struct ext4_xattr_header));
827 	block_header->h_magic = EXT4_XATTR_MAGIC;
828 	block_header->h_refcount = cpu_to_le32(1);
829 	block_header->h_blocks = cpu_to_le32(1);
830 }
831 
832 static void
833 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
834 			   struct ext4_xattr_ibody_header *ibody_header,
835 			   struct ext4_xattr_entry *entry, void *ibody_data_ptr)
836 {
837 	entry->e_name_len = (__u8)item->name_len;
838 	entry->e_name_index = item->name_index;
839 	entry->e_value_offs =
840 	   cpu_to_le16((char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header));
841 	entry->e_value_block = 0;
842 	entry->e_value_size = cpu_to_le32(item->data_size);
843 }
844 
845 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
846 				       struct ext4_xattr_header *block_header,
847 				       struct ext4_xattr_entry *block_entry,
848 				       void *block_data_ptr)
849 {
850 	block_entry->e_name_len = (__u8)item->name_len;
851 	block_entry->e_name_index = item->name_index;
852 	block_entry->e_value_offs =
853 	    cpu_to_le16((char *)block_data_ptr - (char *)block_header);
854 	block_entry->e_value_block = 0;
855 	block_entry->e_value_size = cpu_to_le32(item->data_size);
856 }
857 
858 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
859 {
860 	int ret = 0;
861 	BOOL block_modified = FALSE;
862 	void *ibody_data = NULL;
863 	void *block_data = NULL;
864 	size_t inode_size_rem, block_size_rem;
865 	struct ext4_xattr_ibody_header *ibody_header = NULL;
866 	struct ext4_xattr_header *block_header = NULL;
867 	struct ext4_xattr_entry *entry = NULL;
868 	struct ext4_xattr_entry *block_entry = NULL;
869 	struct ext4_xattr_item *item = NULL;
870 
871 	inode_size_rem = ext4_xattr_inode_space(xattr_ref);
872 	block_size_rem = ext4_xattr_block_space(xattr_ref);
873 	if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
874 		ibody_header = EXT4_XATTR_IHDR(xattr_ref->OnDiskInode);
875 		entry = EXT4_XATTR_IFIRST(ibody_header);
876 	}
877 
878 	if (!xattr_ref->dirty)
879 		goto Finish;
880 	/* If there are enough spaces in the ibody EA table.*/
881 	if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
882 		memset(ibody_header, 0, inode_size_rem);
883 		ibody_header->h_magic = EXT4_XATTR_MAGIC;
884 		ibody_data = (char *)ibody_header + inode_size_rem;
885 		inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
886 
887 		xattr_ref->IsOnDiskInodeDirty = TRUE;
888 	}
889 	/* If we need an extra block to hold the EA entries*/
890 	if (xattr_ref->ea_size > inode_size_rem) {
891 		if (!xattr_ref->block_loaded) {
892 			ret = ext4_xattr_try_alloc_block(xattr_ref);
893 			if (ret != 0)
894 				goto Finish;
895 		}
896 		memset(xattr_ref->block_bh->b_data, 0, xattr_ref->fs->BlockSize);
897 		block_header = EXT4_XATTR_BHDR(xattr_ref->block_bh);
898 		block_entry = EXT4_XATTR_BFIRST(xattr_ref->block_bh);
899 		ext4_xattr_set_block_header(xattr_ref);
900 		block_data = (char *)block_header + block_size_rem;
901 		block_size_rem -= sizeof(struct ext4_xattr_header);
902 
903 		extents_mark_buffer_dirty(xattr_ref->block_bh);
904 	} else {
905 		/* We don't need an extra block.*/
906 		if (xattr_ref->block_loaded) {
907 			block_header = EXT4_XATTR_BHDR(xattr_ref->block_bh);
908 			le32_add_cpu(&block_header->h_refcount, -1);
909 			if (!block_header->h_refcount) {
910 				ext4_xattr_try_free_block(xattr_ref);
911 				block_header = NULL;
912 			} else {
913 				block_entry =
914 				    EXT4_XATTR_BFIRST(xattr_ref->block_bh);
915 				block_data =
916 				    (char *)block_header + block_size_rem;
917 				block_size_rem -=
918 				    sizeof(struct ext4_xattr_header);
919 				xattr_ref->inode_ref->Inode.i_file_acl = 0;
920 
921 				xattr_ref->IsOnDiskInodeDirty = TRUE;
922 				extents_mark_buffer_dirty(xattr_ref->block_bh);
923 			}
924 		}
925 	}
926 
927 	list_for_each_entry(item, &xattr_ref->ordered_list, struct ext4_xattr_item, list_node) {
928 		if (item->in_inode) {
929 			ibody_data = (char *)ibody_data -
930 				     EXT4_XATTR_SIZE(item->data_size);
931 			ext4_xattr_set_inode_entry(item, ibody_header, entry,
932 						   ibody_data);
933 			memcpy(EXT4_XATTR_NAME(entry), item->name,
934 			       item->name_len);
935 			memcpy(ibody_data, item->data, item->data_size);
936 			entry = EXT4_XATTR_NEXT(entry);
937 			inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
938 					  EXT4_XATTR_LEN(item->name_len);
939 
940 			xattr_ref->IsOnDiskInodeDirty = TRUE;
941 			continue;
942 		}
943 		if (EXT4_XATTR_SIZE(item->data_size) +
944 			EXT4_XATTR_LEN(item->name_len) >
945 		    block_size_rem) {
946 			ret = -ENOSPC;
947 			DbgPrint("ext4_xattr.c: IMPOSSIBLE -ENOSPC AS WE DID INSPECTION!\n");
948 			ASSERT(0);
949 		}
950 		block_data =
951 		    (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
952 		ext4_xattr_set_block_entry(item, block_header, block_entry,
953 					   block_data);
954 		memcpy(EXT4_XATTR_NAME(block_entry), item->name,
955 		       item->name_len);
956 		memcpy(block_data, item->data, item->data_size);
957 		ext4_xattr_compute_hash(block_header, block_entry);
958 		block_entry = EXT4_XATTR_NEXT(block_entry);
959 		block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
960 				  EXT4_XATTR_LEN(item->name_len);
961 
962 		block_modified = TRUE;
963 	}
964 	xattr_ref->dirty = FALSE;
965 	if (block_modified) {
966 		ext4_xattr_rehash(block_header,
967 				  EXT4_XATTR_BFIRST(xattr_ref->block_bh));
968 		ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
969 					      xattr_ref->block_bh->b_blocknr,
970 					      block_header);
971 		extents_mark_buffer_dirty(xattr_ref->block_bh);
972 	}
973 
974 Finish:
975 	return ret;
976 }
977 
978 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
979 			   int (*iter)(struct ext4_xattr_ref *ref,
980 				     struct ext4_xattr_item *item,
981 					 BOOL is_last))
982 {
983 	struct ext4_xattr_item *item;
984 	if (!ref->iter_from) {
985 		struct list_head *first_node;
986 		first_node = ref->ordered_list.next;
987 		if (first_node && first_node != &ref->ordered_list) {
988 			ref->iter_from =
989 				list_entry(first_node,
990 					     struct ext4_xattr_item,
991 					     list_node);
992 		}
993 	}
994 
995 	item = ref->iter_from;
996 	while (item) {
997 		struct list_head *next_node;
998 		struct ext4_xattr_item *next_item;
999 		int ret = EXT4_XATTR_ITERATE_CONT;
1000 		next_node = item->list_node.next;
1001 		if (next_node && next_node != &ref->ordered_list)
1002 			next_item = list_entry(next_node, struct ext4_xattr_item,
1003 						 list_node);
1004 		else
1005 			next_item = NULL;
1006 		if (iter)
1007 			ret = iter(ref, item, !next_item);
1008 
1009 		if (ret != EXT4_XATTR_ITERATE_CONT) {
1010 			if (ret == EXT4_XATTR_ITERATE_STOP)
1011 				ref->iter_from = NULL;
1012 
1013 			break;
1014 		}
1015 		item = next_item;
1016 	}
1017 }
1018 
1019 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
1020 {
1021 	ref->iter_from = NULL;
1022 }
1023 
1024 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, __u8 name_index,
1025 		      const char *name, size_t name_len, const void *data,
1026 		      size_t data_size, BOOL replace)
1027 {
1028 	int ret = 0;
1029 	struct ext4_xattr_item *item =
1030 	    ext4_xattr_lookup_item(ref, name_index, name, name_len);
1031 	if (replace) {
1032 		if (!item) {
1033 			ret = -ENODATA;
1034 			goto Finish;
1035 		}
1036 		if (item->data_size != data_size)
1037 			ret = ext4_xattr_resize_item(ref, item, data_size);
1038 
1039 		if (ret != 0) {
1040 			goto Finish;
1041 		}
1042 		memcpy(item->data, data, data_size);
1043 	} else {
1044 		if (item) {
1045 			ret = -EEXIST;
1046 			goto Finish;
1047 		}
1048 		item = ext4_xattr_insert_item(ref, name_index, name, name_len,
1049 					      data, data_size, &ret);
1050 	}
1051 Finish:
1052 	return ret;
1053 }
1054 
1055 int ext4_fs_set_xattr_ordered(struct ext4_xattr_ref *ref, __u8 name_index,
1056 	const char *name, size_t name_len, const void *data,
1057 	size_t data_size)
1058 {
1059 	int ret = 0;
1060 	struct ext4_xattr_item *item =
1061 		ext4_xattr_lookup_item(ref, name_index, name, name_len);
1062 	if (item) {
1063 		ret = -EEXIST;
1064 		goto Finish;
1065 	}
1066 	item = ext4_xattr_insert_item_ordered(ref, name_index, name, name_len,
1067 		data, data_size, &ret);
1068 Finish:
1069 	return ret;
1070 }
1071 
1072 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, __u8 name_index,
1073 			 const char *name, size_t name_len)
1074 {
1075 	return ext4_xattr_remove_item(ref, name_index, name, name_len);
1076 }
1077 
1078 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, __u8 name_index,
1079 		      const char *name, size_t name_len, void *buf,
1080 		      size_t buf_size, size_t *data_size)
1081 {
1082 	int ret = 0;
1083 	size_t item_size = 0;
1084 	struct ext4_xattr_item *item =
1085 	    ext4_xattr_lookup_item(ref, name_index, name, name_len);
1086 
1087 	if (!item) {
1088 		ret = -ENODATA;
1089 		goto Finish;
1090 	}
1091 	item_size = item->data_size;
1092 	if (buf_size > item_size)
1093 		buf_size = item_size;
1094 
1095 	if (buf)
1096 		memcpy(buf, item->data, buf_size);
1097 
1098 Finish:
1099 	if (data_size)
1100 		*data_size = item_size;
1101 
1102 	return ret;
1103 }
1104 
1105 int ext4_fs_get_xattr_ref(PEXT2_IRP_CONTEXT IrpContext, PEXT2_VCB fs, PEXT2_MCB inode_ref,
1106 			  struct ext4_xattr_ref *ref)
1107 {
1108 	int rc;
1109 	ext4_fsblk_t xattr_block;
1110 	xattr_block = inode_ref->Inode.i_file_acl;
1111 	memset(&ref->root, 0, sizeof(struct rb_root));
1112 	ref->ea_size = 0;
1113 	ref->iter_from = NULL;
1114 	if (xattr_block) {
1115 		ref->block_bh = extents_bread(&fs->sb, xattr_block);
1116 		if (!ref->block_bh)
1117 			return -EIO;
1118 
1119 		ref->block_loaded = TRUE;
1120 	} else
1121 		ref->block_loaded = FALSE;
1122 
1123 	ref->inode_ref = inode_ref;
1124 	ref->fs = fs;
1125 	INIT_LIST_HEAD(&ref->ordered_list);
1126 
1127 	ref->OnDiskInode = Ext2AllocateInode(fs);
1128 	if (!ref->OnDiskInode) {
1129 		if (xattr_block) {
1130 			extents_brelse(ref->block_bh);
1131 			ref->block_bh = NULL;
1132 		}
1133 		return -ENOMEM;
1134 	}
1135 	if (!Ext2LoadInodeXattr(fs, &inode_ref->Inode, ref->OnDiskInode)) {
1136 		if (xattr_block) {
1137 			extents_brelse(ref->block_bh);
1138 			ref->block_bh = NULL;
1139 		}
1140 
1141 		Ext2DestroyInode(fs, ref->OnDiskInode);
1142 		return -EIO;
1143 	}
1144 	ref->IsOnDiskInodeDirty = FALSE;
1145 
1146 	if (ext4_xattr_inode_space(ref) <
1147 	   sizeof(struct ext4_xattr_ibody_header) +
1148 	   sizeof(__u32))
1149 		ref->inode_size_rem = 0;
1150 	else {
1151 		ref->inode_size_rem =
1152 			ext4_xattr_inode_space(ref) -
1153 			sizeof(struct ext4_xattr_ibody_header);
1154 	}
1155 
1156 	ref->block_size_rem =
1157 		ext4_xattr_block_space(ref) -
1158 		sizeof(struct ext4_xattr_header) -
1159 		sizeof(__u32);
1160 
1161 	rc = ext4_xattr_fetch(ref);
1162 	if (rc != 0) {
1163 		ext4_xattr_purge_items(ref);
1164 		if (xattr_block) {
1165 			extents_brelse(ref->block_bh);
1166 			ref->block_bh = NULL;
1167 		}
1168 
1169 		Ext2DestroyInode(fs, ref->OnDiskInode);
1170 		return rc;
1171 	}
1172 	ref->IrpContext = IrpContext;
1173 	return 0;
1174 }
1175 
1176 int ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
1177 {
1178 	int ret;
1179 	sector_t orig_file_acl = ref->inode_ref->Inode.i_file_acl;
1180 	ret = ext4_xattr_write_to_disk(ref);
1181 	if (ref->IsOnDiskInodeDirty) {
1182 		ASSERT(ref->fs->InodeSize > EXT4_GOOD_OLD_INODE_SIZE);
1183 
1184 		/* As we may do block allocation in ext4_xattr_write_to_disk */
1185 		if (ret)
1186 			ref->inode_ref->Inode.i_file_acl = orig_file_acl;
1187 
1188 		if (!ret) {
1189 			ret = Ext2SaveInode(ref->IrpContext, ref->fs, &ref->inode_ref->Inode)
1190 				? 0 : -EIO;
1191 			if (!ret) {
1192 				ret = Ext2SaveInodeXattr(ref->IrpContext,
1193 						ref->fs,
1194 						&ref->inode_ref->Inode,
1195 						ref->OnDiskInode)
1196 					? 0 : -EIO;
1197 			}
1198 		}
1199 		ref->IsOnDiskInodeDirty = FALSE;
1200 	}
1201 	if (ref->block_loaded) {
1202 		if (!ret)
1203 			extents_brelse(ref->block_bh);
1204 		else
1205 			extents_bforget(ref->block_bh);
1206 
1207 		ref->block_bh = NULL;
1208 		ref->block_loaded = FALSE;
1209 	}
1210 	ext4_xattr_purge_items(ref);
1211 	Ext2DestroyInode(ref->fs, ref->OnDiskInode);
1212 	ref->OnDiskInode = NULL;
1213 	ref->inode_ref = NULL;
1214 	ref->fs = NULL;
1215 	return ret;
1216 }
1217 
1218 struct xattr_prefix {
1219 	const char *prefix;
1220 	__u8 name_index;
1221 };
1222 
1223 static const struct xattr_prefix prefix_tbl[] = {
1224     {"user.", EXT4_XATTR_INDEX_USER},
1225     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
1226     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
1227     {"trusted.", EXT4_XATTR_INDEX_TRUSTED},
1228     {"security.", EXT4_XATTR_INDEX_SECURITY},
1229     {"system.", EXT4_XATTR_INDEX_SYSTEM},
1230     {"system.richacl", EXT4_XATTR_INDEX_RICHACL},
1231     {NULL, 0},
1232 };
1233 
1234 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
1235 			      __u8 *name_index, size_t *name_len,
1236 			      BOOL *found)
1237 {
1238 	int i;
1239 	ASSERT(name_index);
1240 	ASSERT(found);
1241 
1242 	*found = FALSE;
1243 
1244 	if (!full_name_len) {
1245 		if (name_len)
1246 			*name_len = 0;
1247 
1248 		return NULL;
1249 	}
1250 
1251 	for (i = 0; prefix_tbl[i].prefix; i++) {
1252 		size_t prefix_len = strlen(prefix_tbl[i].prefix);
1253 		if (full_name_len >= prefix_len &&
1254 		    !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
1255 			BOOL require_name =
1256 				prefix_tbl[i].prefix[prefix_len - 1] == '.';
1257 			*name_index = prefix_tbl[i].name_index;
1258 			if (name_len)
1259 				*name_len = full_name_len - prefix_len;
1260 
1261 			if (!(full_name_len - prefix_len) && require_name)
1262 				return NULL;
1263 
1264 			*found = TRUE;
1265 			if (require_name)
1266 				return full_name + prefix_len;
1267 
1268 			return NULL;
1269 		}
1270 	}
1271 	if (name_len)
1272 		*name_len = 0;
1273 
1274 	return NULL;
1275 }
1276 
1277 const char *ext4_get_xattr_name_prefix(__u8 name_index,
1278 				       size_t *ret_prefix_len)
1279 {
1280 	int i;
1281 
1282 	for (i = 0; prefix_tbl[i].prefix; i++) {
1283 		size_t prefix_len = strlen(prefix_tbl[i].prefix);
1284 		if (prefix_tbl[i].name_index == name_index) {
1285 			if (ret_prefix_len)
1286 				*ret_prefix_len = prefix_len;
1287 
1288 			return prefix_tbl[i].prefix;
1289 		}
1290 	}
1291 	if (ret_prefix_len)
1292 		*ret_prefix_len = 0;
1293 
1294 	return NULL;
1295 }
1296