xref: /openbmc/linux/fs/ext4/xattr.c (revision 519b58bb)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/fs/ext4/xattr.c
4  *
5  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
6  *
7  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
8  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
9  * Extended attributes for symlinks and special files added per
10  *  suggestion of Luka Renko <luka.renko@hermes.si>.
11  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
12  *  Red Hat Inc.
13  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
14  *  and Andreas Gruenbacher <agruen@suse.de>.
15  */
16 
17 /*
18  * Extended attributes are stored directly in inodes (on file systems with
19  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
20  * field contains the block number if an inode uses an additional block. All
21  * attributes must fit in the inode and one additional block. Blocks that
22  * contain the identical set of attributes may be shared among several inodes.
23  * Identical blocks are detected by keeping a cache of blocks that have
24  * recently been accessed.
25  *
26  * The attributes in inodes and on blocks have a different header; the entries
27  * are stored in the same format:
28  *
29  *   +------------------+
30  *   | header           |
31  *   | entry 1          | |
32  *   | entry 2          | | growing downwards
33  *   | entry 3          | v
34  *   | four null bytes  |
35  *   | . . .            |
36  *   | value 1          | ^
37  *   | value 3          | | growing upwards
38  *   | value 2          | |
39  *   +------------------+
40  *
41  * The header is followed by multiple entry descriptors. In disk blocks, the
42  * entry descriptors are kept sorted. In inodes, they are unsorted. The
43  * attribute values are aligned to the end of the block in no specific order.
44  *
45  * Locking strategy
46  * ----------------
47  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
48  * EA blocks are only changed if they are exclusive to an inode, so
49  * holding xattr_sem also means that nothing but the EA block's reference
50  * count can change. Multiple writers to the same block are synchronized
51  * by the buffer lock.
52  */
53 
54 #include <linux/init.h>
55 #include <linux/fs.h>
56 #include <linux/slab.h>
57 #include <linux/mbcache.h>
58 #include <linux/quotaops.h>
59 #include <linux/iversion.h>
60 #include "ext4_jbd2.h"
61 #include "ext4.h"
62 #include "xattr.h"
63 #include "acl.h"
64 
65 #ifdef EXT4_XATTR_DEBUG
66 # define ea_idebug(inode, fmt, ...)					\
67 	printk(KERN_DEBUG "inode %s:%lu: " fmt "\n",			\
68 	       inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
69 # define ea_bdebug(bh, fmt, ...)					\
70 	printk(KERN_DEBUG "block %pg:%lu: " fmt "\n",			\
71 	       bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
72 #else
73 # define ea_idebug(inode, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
74 # define ea_bdebug(bh, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
75 #endif
76 
77 static void ext4_xattr_block_cache_insert(struct mb_cache *,
78 					  struct buffer_head *);
79 static struct buffer_head *
80 ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
81 			    struct mb_cache_entry **);
82 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
83 				    size_t value_count);
84 static void ext4_xattr_rehash(struct ext4_xattr_header *);
85 
86 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
87 	[EXT4_XATTR_INDEX_USER]		     = &ext4_xattr_user_handler,
88 #ifdef CONFIG_EXT4_FS_POSIX_ACL
89 	[EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &posix_acl_access_xattr_handler,
90 	[EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
91 #endif
92 	[EXT4_XATTR_INDEX_TRUSTED]	     = &ext4_xattr_trusted_handler,
93 #ifdef CONFIG_EXT4_FS_SECURITY
94 	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
95 #endif
96 	[EXT4_XATTR_INDEX_HURD]		     = &ext4_xattr_hurd_handler,
97 };
98 
99 const struct xattr_handler *ext4_xattr_handlers[] = {
100 	&ext4_xattr_user_handler,
101 	&ext4_xattr_trusted_handler,
102 #ifdef CONFIG_EXT4_FS_POSIX_ACL
103 	&posix_acl_access_xattr_handler,
104 	&posix_acl_default_xattr_handler,
105 #endif
106 #ifdef CONFIG_EXT4_FS_SECURITY
107 	&ext4_xattr_security_handler,
108 #endif
109 	&ext4_xattr_hurd_handler,
110 	NULL
111 };
112 
113 #define EA_BLOCK_CACHE(inode)	(((struct ext4_sb_info *) \
114 				inode->i_sb->s_fs_info)->s_ea_block_cache)
115 
116 #define EA_INODE_CACHE(inode)	(((struct ext4_sb_info *) \
117 				inode->i_sb->s_fs_info)->s_ea_inode_cache)
118 
119 static int
120 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
121 			struct inode *inode);
122 
123 #ifdef CONFIG_LOCKDEP
124 void ext4_xattr_inode_set_class(struct inode *ea_inode)
125 {
126 	lockdep_set_subclass(&ea_inode->i_rwsem, 1);
127 }
128 #endif
129 
130 static __le32 ext4_xattr_block_csum(struct inode *inode,
131 				    sector_t block_nr,
132 				    struct ext4_xattr_header *hdr)
133 {
134 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
135 	__u32 csum;
136 	__le64 dsk_block_nr = cpu_to_le64(block_nr);
137 	__u32 dummy_csum = 0;
138 	int offset = offsetof(struct ext4_xattr_header, h_checksum);
139 
140 	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
141 			   sizeof(dsk_block_nr));
142 	csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
143 	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
144 	offset += sizeof(dummy_csum);
145 	csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
146 			   EXT4_BLOCK_SIZE(inode->i_sb) - offset);
147 
148 	return cpu_to_le32(csum);
149 }
150 
151 static int ext4_xattr_block_csum_verify(struct inode *inode,
152 					struct buffer_head *bh)
153 {
154 	struct ext4_xattr_header *hdr = BHDR(bh);
155 	int ret = 1;
156 
157 	if (ext4_has_metadata_csum(inode->i_sb)) {
158 		lock_buffer(bh);
159 		ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
160 							bh->b_blocknr, hdr));
161 		unlock_buffer(bh);
162 	}
163 	return ret;
164 }
165 
166 static void ext4_xattr_block_csum_set(struct inode *inode,
167 				      struct buffer_head *bh)
168 {
169 	if (ext4_has_metadata_csum(inode->i_sb))
170 		BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
171 						bh->b_blocknr, BHDR(bh));
172 }
173 
174 static inline const struct xattr_handler *
175 ext4_xattr_handler(int name_index)
176 {
177 	const struct xattr_handler *handler = NULL;
178 
179 	if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
180 		handler = ext4_xattr_handler_map[name_index];
181 	return handler;
182 }
183 
184 static int
185 ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
186 			 void *value_start)
187 {
188 	struct ext4_xattr_entry *e = entry;
189 
190 	/* Find the end of the names list */
191 	while (!IS_LAST_ENTRY(e)) {
192 		struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
193 		if ((void *)next >= end)
194 			return -EFSCORRUPTED;
195 		if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
196 			return -EFSCORRUPTED;
197 		e = next;
198 	}
199 
200 	/* Check the values */
201 	while (!IS_LAST_ENTRY(entry)) {
202 		u32 size = le32_to_cpu(entry->e_value_size);
203 
204 		if (size > EXT4_XATTR_SIZE_MAX)
205 			return -EFSCORRUPTED;
206 
207 		if (size != 0 && entry->e_value_inum == 0) {
208 			u16 offs = le16_to_cpu(entry->e_value_offs);
209 			void *value;
210 
211 			/*
212 			 * The value cannot overlap the names, and the value
213 			 * with padding cannot extend beyond 'end'.  Check both
214 			 * the padded and unpadded sizes, since the size may
215 			 * overflow to 0 when adding padding.
216 			 */
217 			if (offs > end - value_start)
218 				return -EFSCORRUPTED;
219 			value = value_start + offs;
220 			if (value < (void *)e + sizeof(u32) ||
221 			    size > end - value ||
222 			    EXT4_XATTR_SIZE(size) > end - value)
223 				return -EFSCORRUPTED;
224 		}
225 		entry = EXT4_XATTR_NEXT(entry);
226 	}
227 
228 	return 0;
229 }
230 
231 static inline int
232 __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
233 			 const char *function, unsigned int line)
234 {
235 	int error = -EFSCORRUPTED;
236 
237 	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
238 	    BHDR(bh)->h_blocks != cpu_to_le32(1))
239 		goto errout;
240 	if (buffer_verified(bh))
241 		return 0;
242 
243 	error = -EFSBADCRC;
244 	if (!ext4_xattr_block_csum_verify(inode, bh))
245 		goto errout;
246 	error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
247 					 bh->b_data);
248 errout:
249 	if (error)
250 		__ext4_error_inode(inode, function, line, 0, -error,
251 				   "corrupted xattr block %llu",
252 				   (unsigned long long) bh->b_blocknr);
253 	else
254 		set_buffer_verified(bh);
255 	return error;
256 }
257 
258 #define ext4_xattr_check_block(inode, bh) \
259 	__ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
260 
261 
262 static int
263 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
264 			 void *end, const char *function, unsigned int line)
265 {
266 	int error = -EFSCORRUPTED;
267 
268 	if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
269 	    (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
270 		goto errout;
271 	error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
272 errout:
273 	if (error)
274 		__ext4_error_inode(inode, function, line, 0, -error,
275 				   "corrupted in-inode xattr");
276 	return error;
277 }
278 
279 #define xattr_check_inode(inode, header, end) \
280 	__xattr_check_inode((inode), (header), (end), __func__, __LINE__)
281 
282 static int
283 xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
284 		 void *end, int name_index, const char *name, int sorted)
285 {
286 	struct ext4_xattr_entry *entry, *next;
287 	size_t name_len;
288 	int cmp = 1;
289 
290 	if (name == NULL)
291 		return -EINVAL;
292 	name_len = strlen(name);
293 	for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
294 		next = EXT4_XATTR_NEXT(entry);
295 		if ((void *) next >= end) {
296 			EXT4_ERROR_INODE(inode, "corrupted xattr entries");
297 			return -EFSCORRUPTED;
298 		}
299 		cmp = name_index - entry->e_name_index;
300 		if (!cmp)
301 			cmp = name_len - entry->e_name_len;
302 		if (!cmp)
303 			cmp = memcmp(name, entry->e_name, name_len);
304 		if (cmp <= 0 && (sorted || cmp == 0))
305 			break;
306 	}
307 	*pentry = entry;
308 	return cmp ? -ENODATA : 0;
309 }
310 
311 static u32
312 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
313 {
314 	return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
315 }
316 
317 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
318 {
319 	return ((u64)ea_inode->i_ctime.tv_sec << 32) |
320 		(u32) inode_peek_iversion_raw(ea_inode);
321 }
322 
323 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
324 {
325 	ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
326 	inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
327 }
328 
329 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
330 {
331 	return (u32)ea_inode->i_atime.tv_sec;
332 }
333 
334 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
335 {
336 	ea_inode->i_atime.tv_sec = hash;
337 }
338 
339 /*
340  * Read the EA value from an inode.
341  */
342 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
343 {
344 	int blocksize = 1 << ea_inode->i_blkbits;
345 	int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
346 	int tail_size = (size % blocksize) ?: blocksize;
347 	struct buffer_head *bhs_inline[8];
348 	struct buffer_head **bhs = bhs_inline;
349 	int i, ret;
350 
351 	if (bh_count > ARRAY_SIZE(bhs_inline)) {
352 		bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
353 		if (!bhs)
354 			return -ENOMEM;
355 	}
356 
357 	ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
358 			       true /* wait */, bhs);
359 	if (ret)
360 		goto free_bhs;
361 
362 	for (i = 0; i < bh_count; i++) {
363 		/* There shouldn't be any holes in ea_inode. */
364 		if (!bhs[i]) {
365 			ret = -EFSCORRUPTED;
366 			goto put_bhs;
367 		}
368 		memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
369 		       i < bh_count - 1 ? blocksize : tail_size);
370 	}
371 	ret = 0;
372 put_bhs:
373 	for (i = 0; i < bh_count; i++)
374 		brelse(bhs[i]);
375 free_bhs:
376 	if (bhs != bhs_inline)
377 		kfree(bhs);
378 	return ret;
379 }
380 
381 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
382 
383 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
384 				 u32 ea_inode_hash, struct inode **ea_inode)
385 {
386 	struct inode *inode;
387 	int err;
388 
389 	inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
390 	if (IS_ERR(inode)) {
391 		err = PTR_ERR(inode);
392 		ext4_error(parent->i_sb,
393 			   "error while reading EA inode %lu err=%d", ea_ino,
394 			   err);
395 		return err;
396 	}
397 
398 	if (is_bad_inode(inode)) {
399 		ext4_error(parent->i_sb,
400 			   "error while reading EA inode %lu is_bad_inode",
401 			   ea_ino);
402 		err = -EIO;
403 		goto error;
404 	}
405 
406 	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
407 		ext4_error(parent->i_sb,
408 			   "EA inode %lu does not have EXT4_EA_INODE_FL flag",
409 			    ea_ino);
410 		err = -EINVAL;
411 		goto error;
412 	}
413 
414 	ext4_xattr_inode_set_class(inode);
415 
416 	/*
417 	 * Check whether this is an old Lustre-style xattr inode. Lustre
418 	 * implementation does not have hash validation, rather it has a
419 	 * backpointer from ea_inode to the parent inode.
420 	 */
421 	if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
422 	    EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
423 	    inode->i_generation == parent->i_generation) {
424 		ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
425 		ext4_xattr_inode_set_ref(inode, 1);
426 	} else {
427 		inode_lock(inode);
428 		inode->i_flags |= S_NOQUOTA;
429 		inode_unlock(inode);
430 	}
431 
432 	*ea_inode = inode;
433 	return 0;
434 error:
435 	iput(inode);
436 	return err;
437 }
438 
439 /* Remove entry from mbcache when EA inode is getting evicted */
440 void ext4_evict_ea_inode(struct inode *inode)
441 {
442 	struct mb_cache_entry *oe;
443 
444 	if (!EA_INODE_CACHE(inode))
445 		return;
446 	/* Wait for entry to get unused so that we can remove it */
447 	while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode),
448 			ext4_xattr_inode_get_hash(inode), inode->i_ino))) {
449 		mb_cache_entry_wait_unused(oe);
450 		mb_cache_entry_put(EA_INODE_CACHE(inode), oe);
451 	}
452 }
453 
454 static int
455 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
456 			       struct ext4_xattr_entry *entry, void *buffer,
457 			       size_t size)
458 {
459 	u32 hash;
460 
461 	/* Verify stored hash matches calculated hash. */
462 	hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
463 	if (hash != ext4_xattr_inode_get_hash(ea_inode))
464 		return -EFSCORRUPTED;
465 
466 	if (entry) {
467 		__le32 e_hash, tmp_data;
468 
469 		/* Verify entry hash. */
470 		tmp_data = cpu_to_le32(hash);
471 		e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
472 					       &tmp_data, 1);
473 		if (e_hash != entry->e_hash)
474 			return -EFSCORRUPTED;
475 	}
476 	return 0;
477 }
478 
479 /*
480  * Read xattr value from the EA inode.
481  */
482 static int
483 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
484 		     void *buffer, size_t size)
485 {
486 	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
487 	struct inode *ea_inode;
488 	int err;
489 
490 	err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
491 				    le32_to_cpu(entry->e_hash), &ea_inode);
492 	if (err) {
493 		ea_inode = NULL;
494 		goto out;
495 	}
496 
497 	if (i_size_read(ea_inode) != size) {
498 		ext4_warning_inode(ea_inode,
499 				   "ea_inode file size=%llu entry size=%zu",
500 				   i_size_read(ea_inode), size);
501 		err = -EFSCORRUPTED;
502 		goto out;
503 	}
504 
505 	err = ext4_xattr_inode_read(ea_inode, buffer, size);
506 	if (err)
507 		goto out;
508 
509 	if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
510 		err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
511 						     size);
512 		if (err) {
513 			ext4_warning_inode(ea_inode,
514 					   "EA inode hash validation failed");
515 			goto out;
516 		}
517 
518 		if (ea_inode_cache)
519 			mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
520 					ext4_xattr_inode_get_hash(ea_inode),
521 					ea_inode->i_ino, true /* reusable */);
522 	}
523 out:
524 	iput(ea_inode);
525 	return err;
526 }
527 
528 static int
529 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
530 		     void *buffer, size_t buffer_size)
531 {
532 	struct buffer_head *bh = NULL;
533 	struct ext4_xattr_entry *entry;
534 	size_t size;
535 	void *end;
536 	int error;
537 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
538 
539 	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
540 		  name_index, name, buffer, (long)buffer_size);
541 
542 	if (!EXT4_I(inode)->i_file_acl)
543 		return -ENODATA;
544 	ea_idebug(inode, "reading block %llu",
545 		  (unsigned long long)EXT4_I(inode)->i_file_acl);
546 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
547 	if (IS_ERR(bh))
548 		return PTR_ERR(bh);
549 	ea_bdebug(bh, "b_count=%d, refcount=%d",
550 		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
551 	error = ext4_xattr_check_block(inode, bh);
552 	if (error)
553 		goto cleanup;
554 	ext4_xattr_block_cache_insert(ea_block_cache, bh);
555 	entry = BFIRST(bh);
556 	end = bh->b_data + bh->b_size;
557 	error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
558 	if (error)
559 		goto cleanup;
560 	size = le32_to_cpu(entry->e_value_size);
561 	error = -ERANGE;
562 	if (unlikely(size > EXT4_XATTR_SIZE_MAX))
563 		goto cleanup;
564 	if (buffer) {
565 		if (size > buffer_size)
566 			goto cleanup;
567 		if (entry->e_value_inum) {
568 			error = ext4_xattr_inode_get(inode, entry, buffer,
569 						     size);
570 			if (error)
571 				goto cleanup;
572 		} else {
573 			u16 offset = le16_to_cpu(entry->e_value_offs);
574 			void *p = bh->b_data + offset;
575 
576 			if (unlikely(p + size > end))
577 				goto cleanup;
578 			memcpy(buffer, p, size);
579 		}
580 	}
581 	error = size;
582 
583 cleanup:
584 	brelse(bh);
585 	return error;
586 }
587 
588 int
589 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
590 		     void *buffer, size_t buffer_size)
591 {
592 	struct ext4_xattr_ibody_header *header;
593 	struct ext4_xattr_entry *entry;
594 	struct ext4_inode *raw_inode;
595 	struct ext4_iloc iloc;
596 	size_t size;
597 	void *end;
598 	int error;
599 
600 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
601 		return -ENODATA;
602 	error = ext4_get_inode_loc(inode, &iloc);
603 	if (error)
604 		return error;
605 	raw_inode = ext4_raw_inode(&iloc);
606 	header = IHDR(inode, raw_inode);
607 	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
608 	error = xattr_check_inode(inode, header, end);
609 	if (error)
610 		goto cleanup;
611 	entry = IFIRST(header);
612 	error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
613 	if (error)
614 		goto cleanup;
615 	size = le32_to_cpu(entry->e_value_size);
616 	error = -ERANGE;
617 	if (unlikely(size > EXT4_XATTR_SIZE_MAX))
618 		goto cleanup;
619 	if (buffer) {
620 		if (size > buffer_size)
621 			goto cleanup;
622 		if (entry->e_value_inum) {
623 			error = ext4_xattr_inode_get(inode, entry, buffer,
624 						     size);
625 			if (error)
626 				goto cleanup;
627 		} else {
628 			u16 offset = le16_to_cpu(entry->e_value_offs);
629 			void *p = (void *)IFIRST(header) + offset;
630 
631 			if (unlikely(p + size > end))
632 				goto cleanup;
633 			memcpy(buffer, p, size);
634 		}
635 	}
636 	error = size;
637 
638 cleanup:
639 	brelse(iloc.bh);
640 	return error;
641 }
642 
643 /*
644  * ext4_xattr_get()
645  *
646  * Copy an extended attribute into the buffer
647  * provided, or compute the buffer size required.
648  * Buffer is NULL to compute the size of the buffer required.
649  *
650  * Returns a negative error number on failure, or the number of bytes
651  * used / required on success.
652  */
653 int
654 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
655 	       void *buffer, size_t buffer_size)
656 {
657 	int error;
658 
659 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
660 		return -EIO;
661 
662 	if (strlen(name) > 255)
663 		return -ERANGE;
664 
665 	down_read(&EXT4_I(inode)->xattr_sem);
666 	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
667 				     buffer_size);
668 	if (error == -ENODATA)
669 		error = ext4_xattr_block_get(inode, name_index, name, buffer,
670 					     buffer_size);
671 	up_read(&EXT4_I(inode)->xattr_sem);
672 	return error;
673 }
674 
675 static int
676 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
677 			char *buffer, size_t buffer_size)
678 {
679 	size_t rest = buffer_size;
680 
681 	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
682 		const struct xattr_handler *handler =
683 			ext4_xattr_handler(entry->e_name_index);
684 
685 		if (handler && (!handler->list || handler->list(dentry))) {
686 			const char *prefix = handler->prefix ?: handler->name;
687 			size_t prefix_len = strlen(prefix);
688 			size_t size = prefix_len + entry->e_name_len + 1;
689 
690 			if (buffer) {
691 				if (size > rest)
692 					return -ERANGE;
693 				memcpy(buffer, prefix, prefix_len);
694 				buffer += prefix_len;
695 				memcpy(buffer, entry->e_name, entry->e_name_len);
696 				buffer += entry->e_name_len;
697 				*buffer++ = 0;
698 			}
699 			rest -= size;
700 		}
701 	}
702 	return buffer_size - rest;  /* total size */
703 }
704 
705 static int
706 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
707 {
708 	struct inode *inode = d_inode(dentry);
709 	struct buffer_head *bh = NULL;
710 	int error;
711 
712 	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
713 		  buffer, (long)buffer_size);
714 
715 	if (!EXT4_I(inode)->i_file_acl)
716 		return 0;
717 	ea_idebug(inode, "reading block %llu",
718 		  (unsigned long long)EXT4_I(inode)->i_file_acl);
719 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
720 	if (IS_ERR(bh))
721 		return PTR_ERR(bh);
722 	ea_bdebug(bh, "b_count=%d, refcount=%d",
723 		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
724 	error = ext4_xattr_check_block(inode, bh);
725 	if (error)
726 		goto cleanup;
727 	ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
728 	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
729 					buffer_size);
730 cleanup:
731 	brelse(bh);
732 	return error;
733 }
734 
735 static int
736 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
737 {
738 	struct inode *inode = d_inode(dentry);
739 	struct ext4_xattr_ibody_header *header;
740 	struct ext4_inode *raw_inode;
741 	struct ext4_iloc iloc;
742 	void *end;
743 	int error;
744 
745 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
746 		return 0;
747 	error = ext4_get_inode_loc(inode, &iloc);
748 	if (error)
749 		return error;
750 	raw_inode = ext4_raw_inode(&iloc);
751 	header = IHDR(inode, raw_inode);
752 	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
753 	error = xattr_check_inode(inode, header, end);
754 	if (error)
755 		goto cleanup;
756 	error = ext4_xattr_list_entries(dentry, IFIRST(header),
757 					buffer, buffer_size);
758 
759 cleanup:
760 	brelse(iloc.bh);
761 	return error;
762 }
763 
764 /*
765  * Inode operation listxattr()
766  *
767  * d_inode(dentry)->i_rwsem: don't care
768  *
769  * Copy a list of attribute names into the buffer
770  * provided, or compute the buffer size required.
771  * Buffer is NULL to compute the size of the buffer required.
772  *
773  * Returns a negative error number on failure, or the number of bytes
774  * used / required on success.
775  */
776 ssize_t
777 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
778 {
779 	int ret, ret2;
780 
781 	down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
782 	ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
783 	if (ret < 0)
784 		goto errout;
785 	if (buffer) {
786 		buffer += ret;
787 		buffer_size -= ret;
788 	}
789 	ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
790 	if (ret < 0)
791 		goto errout;
792 	ret += ret2;
793 errout:
794 	up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
795 	return ret;
796 }
797 
798 /*
799  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
800  * not set, set it.
801  */
802 static void ext4_xattr_update_super_block(handle_t *handle,
803 					  struct super_block *sb)
804 {
805 	if (ext4_has_feature_xattr(sb))
806 		return;
807 
808 	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
809 	if (ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
810 					  EXT4_JTR_NONE) == 0) {
811 		lock_buffer(EXT4_SB(sb)->s_sbh);
812 		ext4_set_feature_xattr(sb);
813 		ext4_superblock_csum_set(sb);
814 		unlock_buffer(EXT4_SB(sb)->s_sbh);
815 		ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
816 	}
817 }
818 
819 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
820 {
821 	struct ext4_iloc iloc = { .bh = NULL };
822 	struct buffer_head *bh = NULL;
823 	struct ext4_inode *raw_inode;
824 	struct ext4_xattr_ibody_header *header;
825 	struct ext4_xattr_entry *entry;
826 	qsize_t ea_inode_refs = 0;
827 	void *end;
828 	int ret;
829 
830 	lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
831 
832 	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
833 		ret = ext4_get_inode_loc(inode, &iloc);
834 		if (ret)
835 			goto out;
836 		raw_inode = ext4_raw_inode(&iloc);
837 		header = IHDR(inode, raw_inode);
838 		end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
839 		ret = xattr_check_inode(inode, header, end);
840 		if (ret)
841 			goto out;
842 
843 		for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
844 		     entry = EXT4_XATTR_NEXT(entry))
845 			if (entry->e_value_inum)
846 				ea_inode_refs++;
847 	}
848 
849 	if (EXT4_I(inode)->i_file_acl) {
850 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
851 		if (IS_ERR(bh)) {
852 			ret = PTR_ERR(bh);
853 			bh = NULL;
854 			goto out;
855 		}
856 
857 		ret = ext4_xattr_check_block(inode, bh);
858 		if (ret)
859 			goto out;
860 
861 		for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
862 		     entry = EXT4_XATTR_NEXT(entry))
863 			if (entry->e_value_inum)
864 				ea_inode_refs++;
865 	}
866 	*usage = ea_inode_refs + 1;
867 	ret = 0;
868 out:
869 	brelse(iloc.bh);
870 	brelse(bh);
871 	return ret;
872 }
873 
874 static inline size_t round_up_cluster(struct inode *inode, size_t length)
875 {
876 	struct super_block *sb = inode->i_sb;
877 	size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
878 				    inode->i_blkbits);
879 	size_t mask = ~(cluster_size - 1);
880 
881 	return (length + cluster_size - 1) & mask;
882 }
883 
884 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
885 {
886 	int err;
887 
888 	err = dquot_alloc_inode(inode);
889 	if (err)
890 		return err;
891 	err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
892 	if (err)
893 		dquot_free_inode(inode);
894 	return err;
895 }
896 
897 static void ext4_xattr_inode_free_quota(struct inode *parent,
898 					struct inode *ea_inode,
899 					size_t len)
900 {
901 	if (ea_inode &&
902 	    ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
903 		return;
904 	dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
905 	dquot_free_inode(parent);
906 }
907 
908 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
909 			     struct buffer_head *block_bh, size_t value_len,
910 			     bool is_create)
911 {
912 	int credits;
913 	int blocks;
914 
915 	/*
916 	 * 1) Owner inode update
917 	 * 2) Ref count update on old xattr block
918 	 * 3) new xattr block
919 	 * 4) block bitmap update for new xattr block
920 	 * 5) group descriptor for new xattr block
921 	 * 6) block bitmap update for old xattr block
922 	 * 7) group descriptor for old block
923 	 *
924 	 * 6 & 7 can happen if we have two racing threads T_a and T_b
925 	 * which are each trying to set an xattr on inodes I_a and I_b
926 	 * which were both initially sharing an xattr block.
927 	 */
928 	credits = 7;
929 
930 	/* Quota updates. */
931 	credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
932 
933 	/*
934 	 * In case of inline data, we may push out the data to a block,
935 	 * so we need to reserve credits for this eventuality
936 	 */
937 	if (inode && ext4_has_inline_data(inode))
938 		credits += ext4_writepage_trans_blocks(inode) + 1;
939 
940 	/* We are done if ea_inode feature is not enabled. */
941 	if (!ext4_has_feature_ea_inode(sb))
942 		return credits;
943 
944 	/* New ea_inode, inode map, block bitmap, group descriptor. */
945 	credits += 4;
946 
947 	/* Data blocks. */
948 	blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
949 
950 	/* Indirection block or one level of extent tree. */
951 	blocks += 1;
952 
953 	/* Block bitmap and group descriptor updates for each block. */
954 	credits += blocks * 2;
955 
956 	/* Blocks themselves. */
957 	credits += blocks;
958 
959 	if (!is_create) {
960 		/* Dereference ea_inode holding old xattr value.
961 		 * Old ea_inode, inode map, block bitmap, group descriptor.
962 		 */
963 		credits += 4;
964 
965 		/* Data blocks for old ea_inode. */
966 		blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
967 
968 		/* Indirection block or one level of extent tree for old
969 		 * ea_inode.
970 		 */
971 		blocks += 1;
972 
973 		/* Block bitmap and group descriptor updates for each block. */
974 		credits += blocks * 2;
975 	}
976 
977 	/* We may need to clone the existing xattr block in which case we need
978 	 * to increment ref counts for existing ea_inodes referenced by it.
979 	 */
980 	if (block_bh) {
981 		struct ext4_xattr_entry *entry = BFIRST(block_bh);
982 
983 		for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
984 			if (entry->e_value_inum)
985 				/* Ref count update on ea_inode. */
986 				credits += 1;
987 	}
988 	return credits;
989 }
990 
991 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
992 				       int ref_change)
993 {
994 	struct ext4_iloc iloc;
995 	s64 ref_count;
996 	int ret;
997 
998 	inode_lock(ea_inode);
999 
1000 	ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
1001 	if (ret)
1002 		goto out;
1003 
1004 	ref_count = ext4_xattr_inode_get_ref(ea_inode);
1005 	ref_count += ref_change;
1006 	ext4_xattr_inode_set_ref(ea_inode, ref_count);
1007 
1008 	if (ref_change > 0) {
1009 		WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1010 			  ea_inode->i_ino, ref_count);
1011 
1012 		if (ref_count == 1) {
1013 			WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1014 				  ea_inode->i_ino, ea_inode->i_nlink);
1015 
1016 			set_nlink(ea_inode, 1);
1017 			ext4_orphan_del(handle, ea_inode);
1018 		}
1019 	} else {
1020 		WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1021 			  ea_inode->i_ino, ref_count);
1022 
1023 		if (ref_count == 0) {
1024 			WARN_ONCE(ea_inode->i_nlink != 1,
1025 				  "EA inode %lu i_nlink=%u",
1026 				  ea_inode->i_ino, ea_inode->i_nlink);
1027 
1028 			clear_nlink(ea_inode);
1029 			ext4_orphan_add(handle, ea_inode);
1030 		}
1031 	}
1032 
1033 	ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1034 	if (ret)
1035 		ext4_warning_inode(ea_inode,
1036 				   "ext4_mark_iloc_dirty() failed ret=%d", ret);
1037 out:
1038 	inode_unlock(ea_inode);
1039 	return ret;
1040 }
1041 
1042 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1043 {
1044 	return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1045 }
1046 
1047 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1048 {
1049 	return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1050 }
1051 
1052 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1053 					struct ext4_xattr_entry *first)
1054 {
1055 	struct inode *ea_inode;
1056 	struct ext4_xattr_entry *entry;
1057 	struct ext4_xattr_entry *failed_entry;
1058 	unsigned int ea_ino;
1059 	int err, saved_err;
1060 
1061 	for (entry = first; !IS_LAST_ENTRY(entry);
1062 	     entry = EXT4_XATTR_NEXT(entry)) {
1063 		if (!entry->e_value_inum)
1064 			continue;
1065 		ea_ino = le32_to_cpu(entry->e_value_inum);
1066 		err = ext4_xattr_inode_iget(parent, ea_ino,
1067 					    le32_to_cpu(entry->e_hash),
1068 					    &ea_inode);
1069 		if (err)
1070 			goto cleanup;
1071 		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1072 		if (err) {
1073 			ext4_warning_inode(ea_inode, "inc ref error %d", err);
1074 			iput(ea_inode);
1075 			goto cleanup;
1076 		}
1077 		iput(ea_inode);
1078 	}
1079 	return 0;
1080 
1081 cleanup:
1082 	saved_err = err;
1083 	failed_entry = entry;
1084 
1085 	for (entry = first; entry != failed_entry;
1086 	     entry = EXT4_XATTR_NEXT(entry)) {
1087 		if (!entry->e_value_inum)
1088 			continue;
1089 		ea_ino = le32_to_cpu(entry->e_value_inum);
1090 		err = ext4_xattr_inode_iget(parent, ea_ino,
1091 					    le32_to_cpu(entry->e_hash),
1092 					    &ea_inode);
1093 		if (err) {
1094 			ext4_warning(parent->i_sb,
1095 				     "cleanup ea_ino %u iget error %d", ea_ino,
1096 				     err);
1097 			continue;
1098 		}
1099 		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1100 		if (err)
1101 			ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1102 					   err);
1103 		iput(ea_inode);
1104 	}
1105 	return saved_err;
1106 }
1107 
1108 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1109 			struct buffer_head *bh, bool block_csum, bool dirty)
1110 {
1111 	int error;
1112 
1113 	if (bh && dirty) {
1114 		if (block_csum)
1115 			ext4_xattr_block_csum_set(inode, bh);
1116 		error = ext4_handle_dirty_metadata(handle, NULL, bh);
1117 		if (error) {
1118 			ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1119 				     error);
1120 			return error;
1121 		}
1122 	}
1123 	return 0;
1124 }
1125 
1126 static void
1127 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1128 			     struct buffer_head *bh,
1129 			     struct ext4_xattr_entry *first, bool block_csum,
1130 			     struct ext4_xattr_inode_array **ea_inode_array,
1131 			     int extra_credits, bool skip_quota)
1132 {
1133 	struct inode *ea_inode;
1134 	struct ext4_xattr_entry *entry;
1135 	bool dirty = false;
1136 	unsigned int ea_ino;
1137 	int err;
1138 	int credits;
1139 
1140 	/* One credit for dec ref on ea_inode, one for orphan list addition, */
1141 	credits = 2 + extra_credits;
1142 
1143 	for (entry = first; !IS_LAST_ENTRY(entry);
1144 	     entry = EXT4_XATTR_NEXT(entry)) {
1145 		if (!entry->e_value_inum)
1146 			continue;
1147 		ea_ino = le32_to_cpu(entry->e_value_inum);
1148 		err = ext4_xattr_inode_iget(parent, ea_ino,
1149 					    le32_to_cpu(entry->e_hash),
1150 					    &ea_inode);
1151 		if (err)
1152 			continue;
1153 
1154 		err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1155 		if (err) {
1156 			ext4_warning_inode(ea_inode,
1157 					   "Expand inode array err=%d", err);
1158 			iput(ea_inode);
1159 			continue;
1160 		}
1161 
1162 		err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1163 			ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1164 			ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1165 					      dirty));
1166 		if (err < 0) {
1167 			ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1168 					   err);
1169 			continue;
1170 		}
1171 		if (err > 0) {
1172 			err = ext4_journal_get_write_access(handle,
1173 					parent->i_sb, bh, EXT4_JTR_NONE);
1174 			if (err) {
1175 				ext4_warning_inode(ea_inode,
1176 						"Re-get write access err=%d",
1177 						err);
1178 				continue;
1179 			}
1180 		}
1181 
1182 		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1183 		if (err) {
1184 			ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1185 					   err);
1186 			continue;
1187 		}
1188 
1189 		if (!skip_quota)
1190 			ext4_xattr_inode_free_quota(parent, ea_inode,
1191 					      le32_to_cpu(entry->e_value_size));
1192 
1193 		/*
1194 		 * Forget about ea_inode within the same transaction that
1195 		 * decrements the ref count. This avoids duplicate decrements in
1196 		 * case the rest of the work spills over to subsequent
1197 		 * transactions.
1198 		 */
1199 		entry->e_value_inum = 0;
1200 		entry->e_value_size = 0;
1201 
1202 		dirty = true;
1203 	}
1204 
1205 	if (dirty) {
1206 		/*
1207 		 * Note that we are deliberately skipping csum calculation for
1208 		 * the final update because we do not expect any journal
1209 		 * restarts until xattr block is freed.
1210 		 */
1211 
1212 		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1213 		if (err)
1214 			ext4_warning_inode(parent,
1215 					   "handle dirty metadata err=%d", err);
1216 	}
1217 }
1218 
1219 /*
1220  * Release the xattr block BH: If the reference count is > 1, decrement it;
1221  * otherwise free the block.
1222  */
1223 static void
1224 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1225 			 struct buffer_head *bh,
1226 			 struct ext4_xattr_inode_array **ea_inode_array,
1227 			 int extra_credits)
1228 {
1229 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1230 	u32 hash, ref;
1231 	int error = 0;
1232 
1233 	BUFFER_TRACE(bh, "get_write_access");
1234 	error = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1235 					      EXT4_JTR_NONE);
1236 	if (error)
1237 		goto out;
1238 
1239 retry_ref:
1240 	lock_buffer(bh);
1241 	hash = le32_to_cpu(BHDR(bh)->h_hash);
1242 	ref = le32_to_cpu(BHDR(bh)->h_refcount);
1243 	if (ref == 1) {
1244 		ea_bdebug(bh, "refcount now=0; freeing");
1245 		/*
1246 		 * This must happen under buffer lock for
1247 		 * ext4_xattr_block_set() to reliably detect freed block
1248 		 */
1249 		if (ea_block_cache) {
1250 			struct mb_cache_entry *oe;
1251 
1252 			oe = mb_cache_entry_delete_or_get(ea_block_cache, hash,
1253 							  bh->b_blocknr);
1254 			if (oe) {
1255 				unlock_buffer(bh);
1256 				mb_cache_entry_wait_unused(oe);
1257 				mb_cache_entry_put(ea_block_cache, oe);
1258 				goto retry_ref;
1259 			}
1260 		}
1261 		get_bh(bh);
1262 		unlock_buffer(bh);
1263 
1264 		if (ext4_has_feature_ea_inode(inode->i_sb))
1265 			ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1266 						     BFIRST(bh),
1267 						     true /* block_csum */,
1268 						     ea_inode_array,
1269 						     extra_credits,
1270 						     true /* skip_quota */);
1271 		ext4_free_blocks(handle, inode, bh, 0, 1,
1272 				 EXT4_FREE_BLOCKS_METADATA |
1273 				 EXT4_FREE_BLOCKS_FORGET);
1274 	} else {
1275 		ref--;
1276 		BHDR(bh)->h_refcount = cpu_to_le32(ref);
1277 		if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1278 			struct mb_cache_entry *ce;
1279 
1280 			if (ea_block_cache) {
1281 				ce = mb_cache_entry_get(ea_block_cache, hash,
1282 							bh->b_blocknr);
1283 				if (ce) {
1284 					ce->e_reusable = 1;
1285 					mb_cache_entry_put(ea_block_cache, ce);
1286 				}
1287 			}
1288 		}
1289 
1290 		ext4_xattr_block_csum_set(inode, bh);
1291 		/*
1292 		 * Beware of this ugliness: Releasing of xattr block references
1293 		 * from different inodes can race and so we have to protect
1294 		 * from a race where someone else frees the block (and releases
1295 		 * its journal_head) before we are done dirtying the buffer. In
1296 		 * nojournal mode this race is harmless and we actually cannot
1297 		 * call ext4_handle_dirty_metadata() with locked buffer as
1298 		 * that function can call sync_dirty_buffer() so for that case
1299 		 * we handle the dirtying after unlocking the buffer.
1300 		 */
1301 		if (ext4_handle_valid(handle))
1302 			error = ext4_handle_dirty_metadata(handle, inode, bh);
1303 		unlock_buffer(bh);
1304 		if (!ext4_handle_valid(handle))
1305 			error = ext4_handle_dirty_metadata(handle, inode, bh);
1306 		if (IS_SYNC(inode))
1307 			ext4_handle_sync(handle);
1308 		dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1309 		ea_bdebug(bh, "refcount now=%d; releasing",
1310 			  le32_to_cpu(BHDR(bh)->h_refcount));
1311 	}
1312 out:
1313 	ext4_std_error(inode->i_sb, error);
1314 	return;
1315 }
1316 
1317 /*
1318  * Find the available free space for EAs. This also returns the total number of
1319  * bytes used by EA entries.
1320  */
1321 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1322 				    size_t *min_offs, void *base, int *total)
1323 {
1324 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1325 		if (!last->e_value_inum && last->e_value_size) {
1326 			size_t offs = le16_to_cpu(last->e_value_offs);
1327 			if (offs < *min_offs)
1328 				*min_offs = offs;
1329 		}
1330 		if (total)
1331 			*total += EXT4_XATTR_LEN(last->e_name_len);
1332 	}
1333 	return (*min_offs - ((void *)last - base) - sizeof(__u32));
1334 }
1335 
1336 /*
1337  * Write the value of the EA in an inode.
1338  */
1339 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1340 				  const void *buf, int bufsize)
1341 {
1342 	struct buffer_head *bh = NULL;
1343 	unsigned long block = 0;
1344 	int blocksize = ea_inode->i_sb->s_blocksize;
1345 	int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1346 	int csize, wsize = 0;
1347 	int ret = 0, ret2 = 0;
1348 	int retries = 0;
1349 
1350 retry:
1351 	while (ret >= 0 && ret < max_blocks) {
1352 		struct ext4_map_blocks map;
1353 		map.m_lblk = block += ret;
1354 		map.m_len = max_blocks -= ret;
1355 
1356 		ret = ext4_map_blocks(handle, ea_inode, &map,
1357 				      EXT4_GET_BLOCKS_CREATE);
1358 		if (ret <= 0) {
1359 			ext4_mark_inode_dirty(handle, ea_inode);
1360 			if (ret == -ENOSPC &&
1361 			    ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1362 				ret = 0;
1363 				goto retry;
1364 			}
1365 			break;
1366 		}
1367 	}
1368 
1369 	if (ret < 0)
1370 		return ret;
1371 
1372 	block = 0;
1373 	while (wsize < bufsize) {
1374 		brelse(bh);
1375 		csize = (bufsize - wsize) > blocksize ? blocksize :
1376 								bufsize - wsize;
1377 		bh = ext4_getblk(handle, ea_inode, block, 0);
1378 		if (IS_ERR(bh))
1379 			return PTR_ERR(bh);
1380 		if (!bh) {
1381 			WARN_ON_ONCE(1);
1382 			EXT4_ERROR_INODE(ea_inode,
1383 					 "ext4_getblk() return bh = NULL");
1384 			return -EFSCORRUPTED;
1385 		}
1386 		ret = ext4_journal_get_write_access(handle, ea_inode->i_sb, bh,
1387 						   EXT4_JTR_NONE);
1388 		if (ret)
1389 			goto out;
1390 
1391 		memcpy(bh->b_data, buf, csize);
1392 		set_buffer_uptodate(bh);
1393 		ext4_handle_dirty_metadata(handle, ea_inode, bh);
1394 
1395 		buf += csize;
1396 		wsize += csize;
1397 		block += 1;
1398 	}
1399 
1400 	inode_lock(ea_inode);
1401 	i_size_write(ea_inode, wsize);
1402 	ext4_update_i_disksize(ea_inode, wsize);
1403 	inode_unlock(ea_inode);
1404 
1405 	ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1406 	if (unlikely(ret2 && !ret))
1407 		ret = ret2;
1408 
1409 out:
1410 	brelse(bh);
1411 
1412 	return ret;
1413 }
1414 
1415 /*
1416  * Create an inode to store the value of a large EA.
1417  */
1418 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1419 					     struct inode *inode, u32 hash)
1420 {
1421 	struct inode *ea_inode = NULL;
1422 	uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1423 	int err;
1424 
1425 	/*
1426 	 * Let the next inode be the goal, so we try and allocate the EA inode
1427 	 * in the same group, or nearby one.
1428 	 */
1429 	ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1430 				  S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1431 				  EXT4_EA_INODE_FL);
1432 	if (!IS_ERR(ea_inode)) {
1433 		ea_inode->i_op = &ext4_file_inode_operations;
1434 		ea_inode->i_fop = &ext4_file_operations;
1435 		ext4_set_aops(ea_inode);
1436 		ext4_xattr_inode_set_class(ea_inode);
1437 		unlock_new_inode(ea_inode);
1438 		ext4_xattr_inode_set_ref(ea_inode, 1);
1439 		ext4_xattr_inode_set_hash(ea_inode, hash);
1440 		err = ext4_mark_inode_dirty(handle, ea_inode);
1441 		if (!err)
1442 			err = ext4_inode_attach_jinode(ea_inode);
1443 		if (err) {
1444 			iput(ea_inode);
1445 			return ERR_PTR(err);
1446 		}
1447 
1448 		/*
1449 		 * Xattr inodes are shared therefore quota charging is performed
1450 		 * at a higher level.
1451 		 */
1452 		dquot_free_inode(ea_inode);
1453 		dquot_drop(ea_inode);
1454 		inode_lock(ea_inode);
1455 		ea_inode->i_flags |= S_NOQUOTA;
1456 		inode_unlock(ea_inode);
1457 	}
1458 
1459 	return ea_inode;
1460 }
1461 
1462 static struct inode *
1463 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1464 			    size_t value_len, u32 hash)
1465 {
1466 	struct inode *ea_inode;
1467 	struct mb_cache_entry *ce;
1468 	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1469 	void *ea_data;
1470 
1471 	if (!ea_inode_cache)
1472 		return NULL;
1473 
1474 	ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1475 	if (!ce)
1476 		return NULL;
1477 
1478 	WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1479 		     !(current->flags & PF_MEMALLOC_NOFS));
1480 
1481 	ea_data = kvmalloc(value_len, GFP_KERNEL);
1482 	if (!ea_data) {
1483 		mb_cache_entry_put(ea_inode_cache, ce);
1484 		return NULL;
1485 	}
1486 
1487 	while (ce) {
1488 		ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1489 				     EXT4_IGET_NORMAL);
1490 		if (!IS_ERR(ea_inode) &&
1491 		    !is_bad_inode(ea_inode) &&
1492 		    (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1493 		    i_size_read(ea_inode) == value_len &&
1494 		    !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1495 		    !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1496 						    value_len) &&
1497 		    !memcmp(value, ea_data, value_len)) {
1498 			mb_cache_entry_touch(ea_inode_cache, ce);
1499 			mb_cache_entry_put(ea_inode_cache, ce);
1500 			kvfree(ea_data);
1501 			return ea_inode;
1502 		}
1503 
1504 		if (!IS_ERR(ea_inode))
1505 			iput(ea_inode);
1506 		ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1507 	}
1508 	kvfree(ea_data);
1509 	return NULL;
1510 }
1511 
1512 /*
1513  * Add value of the EA in an inode.
1514  */
1515 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1516 					  const void *value, size_t value_len,
1517 					  struct inode **ret_inode)
1518 {
1519 	struct inode *ea_inode;
1520 	u32 hash;
1521 	int err;
1522 
1523 	hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1524 	ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1525 	if (ea_inode) {
1526 		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1527 		if (err) {
1528 			iput(ea_inode);
1529 			return err;
1530 		}
1531 
1532 		*ret_inode = ea_inode;
1533 		return 0;
1534 	}
1535 
1536 	/* Create an inode for the EA value */
1537 	ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1538 	if (IS_ERR(ea_inode))
1539 		return PTR_ERR(ea_inode);
1540 
1541 	err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1542 	if (err) {
1543 		ext4_xattr_inode_dec_ref(handle, ea_inode);
1544 		iput(ea_inode);
1545 		return err;
1546 	}
1547 
1548 	if (EA_INODE_CACHE(inode))
1549 		mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1550 				      ea_inode->i_ino, true /* reusable */);
1551 
1552 	*ret_inode = ea_inode;
1553 	return 0;
1554 }
1555 
1556 /*
1557  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1558  * feature is enabled.
1559  */
1560 #define EXT4_XATTR_BLOCK_RESERVE(inode)	min(i_blocksize(inode)/8, 1024U)
1561 
1562 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1563 				struct ext4_xattr_search *s,
1564 				handle_t *handle, struct inode *inode,
1565 				bool is_block)
1566 {
1567 	struct ext4_xattr_entry *last, *next;
1568 	struct ext4_xattr_entry *here = s->here;
1569 	size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1570 	int in_inode = i->in_inode;
1571 	struct inode *old_ea_inode = NULL;
1572 	struct inode *new_ea_inode = NULL;
1573 	size_t old_size, new_size;
1574 	int ret;
1575 
1576 	/* Space used by old and new values. */
1577 	old_size = (!s->not_found && !here->e_value_inum) ?
1578 			EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1579 	new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1580 
1581 	/*
1582 	 * Optimization for the simple case when old and new values have the
1583 	 * same padded sizes. Not applicable if external inodes are involved.
1584 	 */
1585 	if (new_size && new_size == old_size) {
1586 		size_t offs = le16_to_cpu(here->e_value_offs);
1587 		void *val = s->base + offs;
1588 
1589 		here->e_value_size = cpu_to_le32(i->value_len);
1590 		if (i->value == EXT4_ZERO_XATTR_VALUE) {
1591 			memset(val, 0, new_size);
1592 		} else {
1593 			memcpy(val, i->value, i->value_len);
1594 			/* Clear padding bytes. */
1595 			memset(val + i->value_len, 0, new_size - i->value_len);
1596 		}
1597 		goto update_hash;
1598 	}
1599 
1600 	/* Compute min_offs and last. */
1601 	last = s->first;
1602 	for (; !IS_LAST_ENTRY(last); last = next) {
1603 		next = EXT4_XATTR_NEXT(last);
1604 		if ((void *)next >= s->end) {
1605 			EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1606 			ret = -EFSCORRUPTED;
1607 			goto out;
1608 		}
1609 		if (!last->e_value_inum && last->e_value_size) {
1610 			size_t offs = le16_to_cpu(last->e_value_offs);
1611 			if (offs < min_offs)
1612 				min_offs = offs;
1613 		}
1614 	}
1615 
1616 	/* Check whether we have enough space. */
1617 	if (i->value) {
1618 		size_t free;
1619 
1620 		free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1621 		if (!s->not_found)
1622 			free += EXT4_XATTR_LEN(name_len) + old_size;
1623 
1624 		if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1625 			ret = -ENOSPC;
1626 			goto out;
1627 		}
1628 
1629 		/*
1630 		 * If storing the value in an external inode is an option,
1631 		 * reserve space for xattr entries/names in the external
1632 		 * attribute block so that a long value does not occupy the
1633 		 * whole space and prevent further entries being added.
1634 		 */
1635 		if (ext4_has_feature_ea_inode(inode->i_sb) &&
1636 		    new_size && is_block &&
1637 		    (min_offs + old_size - new_size) <
1638 					EXT4_XATTR_BLOCK_RESERVE(inode)) {
1639 			ret = -ENOSPC;
1640 			goto out;
1641 		}
1642 	}
1643 
1644 	/*
1645 	 * Getting access to old and new ea inodes is subject to failures.
1646 	 * Finish that work before doing any modifications to the xattr data.
1647 	 */
1648 	if (!s->not_found && here->e_value_inum) {
1649 		ret = ext4_xattr_inode_iget(inode,
1650 					    le32_to_cpu(here->e_value_inum),
1651 					    le32_to_cpu(here->e_hash),
1652 					    &old_ea_inode);
1653 		if (ret) {
1654 			old_ea_inode = NULL;
1655 			goto out;
1656 		}
1657 	}
1658 	if (i->value && in_inode) {
1659 		WARN_ON_ONCE(!i->value_len);
1660 
1661 		ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1662 		if (ret)
1663 			goto out;
1664 
1665 		ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1666 						     i->value_len,
1667 						     &new_ea_inode);
1668 		if (ret) {
1669 			new_ea_inode = NULL;
1670 			ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1671 			goto out;
1672 		}
1673 	}
1674 
1675 	if (old_ea_inode) {
1676 		/* We are ready to release ref count on the old_ea_inode. */
1677 		ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1678 		if (ret) {
1679 			/* Release newly required ref count on new_ea_inode. */
1680 			if (new_ea_inode) {
1681 				int err;
1682 
1683 				err = ext4_xattr_inode_dec_ref(handle,
1684 							       new_ea_inode);
1685 				if (err)
1686 					ext4_warning_inode(new_ea_inode,
1687 						  "dec ref new_ea_inode err=%d",
1688 						  err);
1689 				ext4_xattr_inode_free_quota(inode, new_ea_inode,
1690 							    i->value_len);
1691 			}
1692 			goto out;
1693 		}
1694 
1695 		ext4_xattr_inode_free_quota(inode, old_ea_inode,
1696 					    le32_to_cpu(here->e_value_size));
1697 	}
1698 
1699 	/* No failures allowed past this point. */
1700 
1701 	if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1702 		/* Remove the old value. */
1703 		void *first_val = s->base + min_offs;
1704 		size_t offs = le16_to_cpu(here->e_value_offs);
1705 		void *val = s->base + offs;
1706 
1707 		memmove(first_val + old_size, first_val, val - first_val);
1708 		memset(first_val, 0, old_size);
1709 		min_offs += old_size;
1710 
1711 		/* Adjust all value offsets. */
1712 		last = s->first;
1713 		while (!IS_LAST_ENTRY(last)) {
1714 			size_t o = le16_to_cpu(last->e_value_offs);
1715 
1716 			if (!last->e_value_inum &&
1717 			    last->e_value_size && o < offs)
1718 				last->e_value_offs = cpu_to_le16(o + old_size);
1719 			last = EXT4_XATTR_NEXT(last);
1720 		}
1721 	}
1722 
1723 	if (!i->value) {
1724 		/* Remove old name. */
1725 		size_t size = EXT4_XATTR_LEN(name_len);
1726 
1727 		last = ENTRY((void *)last - size);
1728 		memmove(here, (void *)here + size,
1729 			(void *)last - (void *)here + sizeof(__u32));
1730 		memset(last, 0, size);
1731 	} else if (s->not_found) {
1732 		/* Insert new name. */
1733 		size_t size = EXT4_XATTR_LEN(name_len);
1734 		size_t rest = (void *)last - (void *)here + sizeof(__u32);
1735 
1736 		memmove((void *)here + size, here, rest);
1737 		memset(here, 0, size);
1738 		here->e_name_index = i->name_index;
1739 		here->e_name_len = name_len;
1740 		memcpy(here->e_name, i->name, name_len);
1741 	} else {
1742 		/* This is an update, reset value info. */
1743 		here->e_value_inum = 0;
1744 		here->e_value_offs = 0;
1745 		here->e_value_size = 0;
1746 	}
1747 
1748 	if (i->value) {
1749 		/* Insert new value. */
1750 		if (in_inode) {
1751 			here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1752 		} else if (i->value_len) {
1753 			void *val = s->base + min_offs - new_size;
1754 
1755 			here->e_value_offs = cpu_to_le16(min_offs - new_size);
1756 			if (i->value == EXT4_ZERO_XATTR_VALUE) {
1757 				memset(val, 0, new_size);
1758 			} else {
1759 				memcpy(val, i->value, i->value_len);
1760 				/* Clear padding bytes. */
1761 				memset(val + i->value_len, 0,
1762 				       new_size - i->value_len);
1763 			}
1764 		}
1765 		here->e_value_size = cpu_to_le32(i->value_len);
1766 	}
1767 
1768 update_hash:
1769 	if (i->value) {
1770 		__le32 hash = 0;
1771 
1772 		/* Entry hash calculation. */
1773 		if (in_inode) {
1774 			__le32 crc32c_hash;
1775 
1776 			/*
1777 			 * Feed crc32c hash instead of the raw value for entry
1778 			 * hash calculation. This is to avoid walking
1779 			 * potentially long value buffer again.
1780 			 */
1781 			crc32c_hash = cpu_to_le32(
1782 				       ext4_xattr_inode_get_hash(new_ea_inode));
1783 			hash = ext4_xattr_hash_entry(here->e_name,
1784 						     here->e_name_len,
1785 						     &crc32c_hash, 1);
1786 		} else if (is_block) {
1787 			__le32 *value = s->base + le16_to_cpu(
1788 							here->e_value_offs);
1789 
1790 			hash = ext4_xattr_hash_entry(here->e_name,
1791 						     here->e_name_len, value,
1792 						     new_size >> 2);
1793 		}
1794 		here->e_hash = hash;
1795 	}
1796 
1797 	if (is_block)
1798 		ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1799 
1800 	ret = 0;
1801 out:
1802 	iput(old_ea_inode);
1803 	iput(new_ea_inode);
1804 	return ret;
1805 }
1806 
1807 struct ext4_xattr_block_find {
1808 	struct ext4_xattr_search s;
1809 	struct buffer_head *bh;
1810 };
1811 
1812 static int
1813 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1814 		      struct ext4_xattr_block_find *bs)
1815 {
1816 	struct super_block *sb = inode->i_sb;
1817 	int error;
1818 
1819 	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1820 		  i->name_index, i->name, i->value, (long)i->value_len);
1821 
1822 	if (EXT4_I(inode)->i_file_acl) {
1823 		/* The inode already has an extended attribute block. */
1824 		bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1825 		if (IS_ERR(bs->bh)) {
1826 			error = PTR_ERR(bs->bh);
1827 			bs->bh = NULL;
1828 			return error;
1829 		}
1830 		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1831 			atomic_read(&(bs->bh->b_count)),
1832 			le32_to_cpu(BHDR(bs->bh)->h_refcount));
1833 		error = ext4_xattr_check_block(inode, bs->bh);
1834 		if (error)
1835 			return error;
1836 		/* Find the named attribute. */
1837 		bs->s.base = BHDR(bs->bh);
1838 		bs->s.first = BFIRST(bs->bh);
1839 		bs->s.end = bs->bh->b_data + bs->bh->b_size;
1840 		bs->s.here = bs->s.first;
1841 		error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1842 					 i->name_index, i->name, 1);
1843 		if (error && error != -ENODATA)
1844 			return error;
1845 		bs->s.not_found = error;
1846 	}
1847 	return 0;
1848 }
1849 
1850 static int
1851 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1852 		     struct ext4_xattr_info *i,
1853 		     struct ext4_xattr_block_find *bs)
1854 {
1855 	struct super_block *sb = inode->i_sb;
1856 	struct buffer_head *new_bh = NULL;
1857 	struct ext4_xattr_search s_copy = bs->s;
1858 	struct ext4_xattr_search *s = &s_copy;
1859 	struct mb_cache_entry *ce = NULL;
1860 	int error = 0;
1861 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1862 	struct inode *ea_inode = NULL, *tmp_inode;
1863 	size_t old_ea_inode_quota = 0;
1864 	unsigned int ea_ino;
1865 
1866 
1867 #define header(x) ((struct ext4_xattr_header *)(x))
1868 
1869 	if (s->base) {
1870 		int offset = (char *)s->here - bs->bh->b_data;
1871 
1872 		BUFFER_TRACE(bs->bh, "get_write_access");
1873 		error = ext4_journal_get_write_access(handle, sb, bs->bh,
1874 						      EXT4_JTR_NONE);
1875 		if (error)
1876 			goto cleanup;
1877 		lock_buffer(bs->bh);
1878 
1879 		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1880 			__u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1881 
1882 			/*
1883 			 * This must happen under buffer lock for
1884 			 * ext4_xattr_block_set() to reliably detect modified
1885 			 * block
1886 			 */
1887 			if (ea_block_cache) {
1888 				struct mb_cache_entry *oe;
1889 
1890 				oe = mb_cache_entry_delete_or_get(ea_block_cache,
1891 					hash, bs->bh->b_blocknr);
1892 				if (oe) {
1893 					/*
1894 					 * Xattr block is getting reused. Leave
1895 					 * it alone.
1896 					 */
1897 					mb_cache_entry_put(ea_block_cache, oe);
1898 					goto clone_block;
1899 				}
1900 			}
1901 			ea_bdebug(bs->bh, "modifying in-place");
1902 			error = ext4_xattr_set_entry(i, s, handle, inode,
1903 						     true /* is_block */);
1904 			ext4_xattr_block_csum_set(inode, bs->bh);
1905 			unlock_buffer(bs->bh);
1906 			if (error == -EFSCORRUPTED)
1907 				goto bad_block;
1908 			if (!error)
1909 				error = ext4_handle_dirty_metadata(handle,
1910 								   inode,
1911 								   bs->bh);
1912 			if (error)
1913 				goto cleanup;
1914 			goto inserted;
1915 		}
1916 clone_block:
1917 		unlock_buffer(bs->bh);
1918 		ea_bdebug(bs->bh, "cloning");
1919 		s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
1920 		error = -ENOMEM;
1921 		if (s->base == NULL)
1922 			goto cleanup;
1923 		s->first = ENTRY(header(s->base)+1);
1924 		header(s->base)->h_refcount = cpu_to_le32(1);
1925 		s->here = ENTRY(s->base + offset);
1926 		s->end = s->base + bs->bh->b_size;
1927 
1928 		/*
1929 		 * If existing entry points to an xattr inode, we need
1930 		 * to prevent ext4_xattr_set_entry() from decrementing
1931 		 * ref count on it because the reference belongs to the
1932 		 * original block. In this case, make the entry look
1933 		 * like it has an empty value.
1934 		 */
1935 		if (!s->not_found && s->here->e_value_inum) {
1936 			ea_ino = le32_to_cpu(s->here->e_value_inum);
1937 			error = ext4_xattr_inode_iget(inode, ea_ino,
1938 				      le32_to_cpu(s->here->e_hash),
1939 				      &tmp_inode);
1940 			if (error)
1941 				goto cleanup;
1942 
1943 			if (!ext4_test_inode_state(tmp_inode,
1944 					EXT4_STATE_LUSTRE_EA_INODE)) {
1945 				/*
1946 				 * Defer quota free call for previous
1947 				 * inode until success is guaranteed.
1948 				 */
1949 				old_ea_inode_quota = le32_to_cpu(
1950 						s->here->e_value_size);
1951 			}
1952 			iput(tmp_inode);
1953 
1954 			s->here->e_value_inum = 0;
1955 			s->here->e_value_size = 0;
1956 		}
1957 	} else {
1958 		/* Allocate a buffer where we construct the new block. */
1959 		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1960 		error = -ENOMEM;
1961 		if (s->base == NULL)
1962 			goto cleanup;
1963 		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1964 		header(s->base)->h_blocks = cpu_to_le32(1);
1965 		header(s->base)->h_refcount = cpu_to_le32(1);
1966 		s->first = ENTRY(header(s->base)+1);
1967 		s->here = ENTRY(header(s->base)+1);
1968 		s->end = s->base + sb->s_blocksize;
1969 	}
1970 
1971 	error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1972 	if (error == -EFSCORRUPTED)
1973 		goto bad_block;
1974 	if (error)
1975 		goto cleanup;
1976 
1977 	if (i->value && s->here->e_value_inum) {
1978 		/*
1979 		 * A ref count on ea_inode has been taken as part of the call to
1980 		 * ext4_xattr_set_entry() above. We would like to drop this
1981 		 * extra ref but we have to wait until the xattr block is
1982 		 * initialized and has its own ref count on the ea_inode.
1983 		 */
1984 		ea_ino = le32_to_cpu(s->here->e_value_inum);
1985 		error = ext4_xattr_inode_iget(inode, ea_ino,
1986 					      le32_to_cpu(s->here->e_hash),
1987 					      &ea_inode);
1988 		if (error) {
1989 			ea_inode = NULL;
1990 			goto cleanup;
1991 		}
1992 	}
1993 
1994 inserted:
1995 	if (!IS_LAST_ENTRY(s->first)) {
1996 		new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1997 						     &ce);
1998 		if (new_bh) {
1999 			/* We found an identical block in the cache. */
2000 			if (new_bh == bs->bh)
2001 				ea_bdebug(new_bh, "keeping");
2002 			else {
2003 				u32 ref;
2004 
2005 				WARN_ON_ONCE(dquot_initialize_needed(inode));
2006 
2007 				/* The old block is released after updating
2008 				   the inode. */
2009 				error = dquot_alloc_block(inode,
2010 						EXT4_C2B(EXT4_SB(sb), 1));
2011 				if (error)
2012 					goto cleanup;
2013 				BUFFER_TRACE(new_bh, "get_write_access");
2014 				error = ext4_journal_get_write_access(
2015 						handle, sb, new_bh,
2016 						EXT4_JTR_NONE);
2017 				if (error)
2018 					goto cleanup_dquot;
2019 				lock_buffer(new_bh);
2020 				/*
2021 				 * We have to be careful about races with
2022 				 * adding references to xattr block. Once we
2023 				 * hold buffer lock xattr block's state is
2024 				 * stable so we can check the additional
2025 				 * reference fits.
2026 				 */
2027 				ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2028 				if (ref > EXT4_XATTR_REFCOUNT_MAX) {
2029 					/*
2030 					 * Undo everything and check mbcache
2031 					 * again.
2032 					 */
2033 					unlock_buffer(new_bh);
2034 					dquot_free_block(inode,
2035 							 EXT4_C2B(EXT4_SB(sb),
2036 								  1));
2037 					brelse(new_bh);
2038 					mb_cache_entry_put(ea_block_cache, ce);
2039 					ce = NULL;
2040 					new_bh = NULL;
2041 					goto inserted;
2042 				}
2043 				BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2044 				if (ref == EXT4_XATTR_REFCOUNT_MAX)
2045 					ce->e_reusable = 0;
2046 				ea_bdebug(new_bh, "reusing; refcount now=%d",
2047 					  ref);
2048 				ext4_xattr_block_csum_set(inode, new_bh);
2049 				unlock_buffer(new_bh);
2050 				error = ext4_handle_dirty_metadata(handle,
2051 								   inode,
2052 								   new_bh);
2053 				if (error)
2054 					goto cleanup_dquot;
2055 			}
2056 			mb_cache_entry_touch(ea_block_cache, ce);
2057 			mb_cache_entry_put(ea_block_cache, ce);
2058 			ce = NULL;
2059 		} else if (bs->bh && s->base == bs->bh->b_data) {
2060 			/* We were modifying this block in-place. */
2061 			ea_bdebug(bs->bh, "keeping this block");
2062 			ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2063 			new_bh = bs->bh;
2064 			get_bh(new_bh);
2065 		} else {
2066 			/* We need to allocate a new block */
2067 			ext4_fsblk_t goal, block;
2068 
2069 			WARN_ON_ONCE(dquot_initialize_needed(inode));
2070 
2071 			goal = ext4_group_first_block_no(sb,
2072 						EXT4_I(inode)->i_block_group);
2073 
2074 			/* non-extent files can't have physical blocks past 2^32 */
2075 			if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2076 				goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2077 
2078 			block = ext4_new_meta_blocks(handle, inode, goal, 0,
2079 						     NULL, &error);
2080 			if (error)
2081 				goto cleanup;
2082 
2083 			if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2084 				BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2085 
2086 			ea_idebug(inode, "creating block %llu",
2087 				  (unsigned long long)block);
2088 
2089 			new_bh = sb_getblk(sb, block);
2090 			if (unlikely(!new_bh)) {
2091 				error = -ENOMEM;
2092 getblk_failed:
2093 				ext4_free_blocks(handle, inode, NULL, block, 1,
2094 						 EXT4_FREE_BLOCKS_METADATA);
2095 				goto cleanup;
2096 			}
2097 			error = ext4_xattr_inode_inc_ref_all(handle, inode,
2098 						      ENTRY(header(s->base)+1));
2099 			if (error)
2100 				goto getblk_failed;
2101 			if (ea_inode) {
2102 				/* Drop the extra ref on ea_inode. */
2103 				error = ext4_xattr_inode_dec_ref(handle,
2104 								 ea_inode);
2105 				if (error)
2106 					ext4_warning_inode(ea_inode,
2107 							   "dec ref error=%d",
2108 							   error);
2109 				iput(ea_inode);
2110 				ea_inode = NULL;
2111 			}
2112 
2113 			lock_buffer(new_bh);
2114 			error = ext4_journal_get_create_access(handle, sb,
2115 							new_bh, EXT4_JTR_NONE);
2116 			if (error) {
2117 				unlock_buffer(new_bh);
2118 				error = -EIO;
2119 				goto getblk_failed;
2120 			}
2121 			memcpy(new_bh->b_data, s->base, new_bh->b_size);
2122 			ext4_xattr_block_csum_set(inode, new_bh);
2123 			set_buffer_uptodate(new_bh);
2124 			unlock_buffer(new_bh);
2125 			ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2126 			error = ext4_handle_dirty_metadata(handle, inode,
2127 							   new_bh);
2128 			if (error)
2129 				goto cleanup;
2130 		}
2131 	}
2132 
2133 	if (old_ea_inode_quota)
2134 		ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2135 
2136 	/* Update the inode. */
2137 	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2138 
2139 	/* Drop the previous xattr block. */
2140 	if (bs->bh && bs->bh != new_bh) {
2141 		struct ext4_xattr_inode_array *ea_inode_array = NULL;
2142 
2143 		ext4_xattr_release_block(handle, inode, bs->bh,
2144 					 &ea_inode_array,
2145 					 0 /* extra_credits */);
2146 		ext4_xattr_inode_array_free(ea_inode_array);
2147 	}
2148 	error = 0;
2149 
2150 cleanup:
2151 	if (ea_inode) {
2152 		int error2;
2153 
2154 		error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2155 		if (error2)
2156 			ext4_warning_inode(ea_inode, "dec ref error=%d",
2157 					   error2);
2158 
2159 		/* If there was an error, revert the quota charge. */
2160 		if (error)
2161 			ext4_xattr_inode_free_quota(inode, ea_inode,
2162 						    i_size_read(ea_inode));
2163 		iput(ea_inode);
2164 	}
2165 	if (ce)
2166 		mb_cache_entry_put(ea_block_cache, ce);
2167 	brelse(new_bh);
2168 	if (!(bs->bh && s->base == bs->bh->b_data))
2169 		kfree(s->base);
2170 
2171 	return error;
2172 
2173 cleanup_dquot:
2174 	dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2175 	goto cleanup;
2176 
2177 bad_block:
2178 	EXT4_ERROR_INODE(inode, "bad block %llu",
2179 			 EXT4_I(inode)->i_file_acl);
2180 	goto cleanup;
2181 
2182 #undef header
2183 }
2184 
2185 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2186 			  struct ext4_xattr_ibody_find *is)
2187 {
2188 	struct ext4_xattr_ibody_header *header;
2189 	struct ext4_inode *raw_inode;
2190 	int error;
2191 
2192 	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2193 		return 0;
2194 
2195 	raw_inode = ext4_raw_inode(&is->iloc);
2196 	header = IHDR(inode, raw_inode);
2197 	is->s.base = is->s.first = IFIRST(header);
2198 	is->s.here = is->s.first;
2199 	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2200 	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2201 		error = xattr_check_inode(inode, header, is->s.end);
2202 		if (error)
2203 			return error;
2204 		/* Find the named attribute. */
2205 		error = xattr_find_entry(inode, &is->s.here, is->s.end,
2206 					 i->name_index, i->name, 0);
2207 		if (error && error != -ENODATA)
2208 			return error;
2209 		is->s.not_found = error;
2210 	}
2211 	return 0;
2212 }
2213 
2214 int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2215 				struct ext4_xattr_info *i,
2216 				struct ext4_xattr_ibody_find *is)
2217 {
2218 	struct ext4_xattr_ibody_header *header;
2219 	struct ext4_xattr_search *s = &is->s;
2220 	int error;
2221 
2222 	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2223 		return -ENOSPC;
2224 
2225 	error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2226 	if (error)
2227 		return error;
2228 	header = IHDR(inode, ext4_raw_inode(&is->iloc));
2229 	if (!IS_LAST_ENTRY(s->first)) {
2230 		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2231 		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2232 	} else {
2233 		header->h_magic = cpu_to_le32(0);
2234 		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2235 	}
2236 	return 0;
2237 }
2238 
2239 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2240 				 struct ext4_xattr_info *i)
2241 {
2242 	void *value;
2243 
2244 	/* When e_value_inum is set the value is stored externally. */
2245 	if (s->here->e_value_inum)
2246 		return 0;
2247 	if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2248 		return 0;
2249 	value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2250 	return !memcmp(value, i->value, i->value_len);
2251 }
2252 
2253 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2254 {
2255 	struct buffer_head *bh;
2256 	int error;
2257 
2258 	if (!EXT4_I(inode)->i_file_acl)
2259 		return NULL;
2260 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2261 	if (IS_ERR(bh))
2262 		return bh;
2263 	error = ext4_xattr_check_block(inode, bh);
2264 	if (error) {
2265 		brelse(bh);
2266 		return ERR_PTR(error);
2267 	}
2268 	return bh;
2269 }
2270 
2271 /*
2272  * ext4_xattr_set_handle()
2273  *
2274  * Create, replace or remove an extended attribute for this inode.  Value
2275  * is NULL to remove an existing extended attribute, and non-NULL to
2276  * either replace an existing extended attribute, or create a new extended
2277  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2278  * specify that an extended attribute must exist and must not exist
2279  * previous to the call, respectively.
2280  *
2281  * Returns 0, or a negative error number on failure.
2282  */
2283 int
2284 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2285 		      const char *name, const void *value, size_t value_len,
2286 		      int flags)
2287 {
2288 	struct ext4_xattr_info i = {
2289 		.name_index = name_index,
2290 		.name = name,
2291 		.value = value,
2292 		.value_len = value_len,
2293 		.in_inode = 0,
2294 	};
2295 	struct ext4_xattr_ibody_find is = {
2296 		.s = { .not_found = -ENODATA, },
2297 	};
2298 	struct ext4_xattr_block_find bs = {
2299 		.s = { .not_found = -ENODATA, },
2300 	};
2301 	int no_expand;
2302 	int error;
2303 
2304 	if (!name)
2305 		return -EINVAL;
2306 	if (strlen(name) > 255)
2307 		return -ERANGE;
2308 
2309 	ext4_write_lock_xattr(inode, &no_expand);
2310 
2311 	/* Check journal credits under write lock. */
2312 	if (ext4_handle_valid(handle)) {
2313 		struct buffer_head *bh;
2314 		int credits;
2315 
2316 		bh = ext4_xattr_get_block(inode);
2317 		if (IS_ERR(bh)) {
2318 			error = PTR_ERR(bh);
2319 			goto cleanup;
2320 		}
2321 
2322 		credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2323 						   value_len,
2324 						   flags & XATTR_CREATE);
2325 		brelse(bh);
2326 
2327 		if (jbd2_handle_buffer_credits(handle) < credits) {
2328 			error = -ENOSPC;
2329 			goto cleanup;
2330 		}
2331 		WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2332 	}
2333 
2334 	error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2335 	if (error)
2336 		goto cleanup;
2337 
2338 	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2339 		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2340 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2341 		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2342 	}
2343 
2344 	error = ext4_xattr_ibody_find(inode, &i, &is);
2345 	if (error)
2346 		goto cleanup;
2347 	if (is.s.not_found)
2348 		error = ext4_xattr_block_find(inode, &i, &bs);
2349 	if (error)
2350 		goto cleanup;
2351 	if (is.s.not_found && bs.s.not_found) {
2352 		error = -ENODATA;
2353 		if (flags & XATTR_REPLACE)
2354 			goto cleanup;
2355 		error = 0;
2356 		if (!value)
2357 			goto cleanup;
2358 	} else {
2359 		error = -EEXIST;
2360 		if (flags & XATTR_CREATE)
2361 			goto cleanup;
2362 	}
2363 
2364 	if (!value) {
2365 		if (!is.s.not_found)
2366 			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2367 		else if (!bs.s.not_found)
2368 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2369 	} else {
2370 		error = 0;
2371 		/* Xattr value did not change? Save us some work and bail out */
2372 		if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2373 			goto cleanup;
2374 		if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2375 			goto cleanup;
2376 
2377 		if (ext4_has_feature_ea_inode(inode->i_sb) &&
2378 		    (EXT4_XATTR_SIZE(i.value_len) >
2379 			EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2380 			i.in_inode = 1;
2381 retry_inode:
2382 		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2383 		if (!error && !bs.s.not_found) {
2384 			i.value = NULL;
2385 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2386 		} else if (error == -ENOSPC) {
2387 			if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2388 				brelse(bs.bh);
2389 				bs.bh = NULL;
2390 				error = ext4_xattr_block_find(inode, &i, &bs);
2391 				if (error)
2392 					goto cleanup;
2393 			}
2394 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2395 			if (!error && !is.s.not_found) {
2396 				i.value = NULL;
2397 				error = ext4_xattr_ibody_set(handle, inode, &i,
2398 							     &is);
2399 			} else if (error == -ENOSPC) {
2400 				/*
2401 				 * Xattr does not fit in the block, store at
2402 				 * external inode if possible.
2403 				 */
2404 				if (ext4_has_feature_ea_inode(inode->i_sb) &&
2405 				    i.value_len && !i.in_inode) {
2406 					i.in_inode = 1;
2407 					goto retry_inode;
2408 				}
2409 			}
2410 		}
2411 	}
2412 	if (!error) {
2413 		ext4_xattr_update_super_block(handle, inode->i_sb);
2414 		inode->i_ctime = current_time(inode);
2415 		inode_inc_iversion(inode);
2416 		if (!value)
2417 			no_expand = 0;
2418 		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2419 		/*
2420 		 * The bh is consumed by ext4_mark_iloc_dirty, even with
2421 		 * error != 0.
2422 		 */
2423 		is.iloc.bh = NULL;
2424 		if (IS_SYNC(inode))
2425 			ext4_handle_sync(handle);
2426 	}
2427 	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2428 
2429 cleanup:
2430 	brelse(is.iloc.bh);
2431 	brelse(bs.bh);
2432 	ext4_write_unlock_xattr(inode, &no_expand);
2433 	return error;
2434 }
2435 
2436 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2437 			   bool is_create, int *credits)
2438 {
2439 	struct buffer_head *bh;
2440 	int err;
2441 
2442 	*credits = 0;
2443 
2444 	if (!EXT4_SB(inode->i_sb)->s_journal)
2445 		return 0;
2446 
2447 	down_read(&EXT4_I(inode)->xattr_sem);
2448 
2449 	bh = ext4_xattr_get_block(inode);
2450 	if (IS_ERR(bh)) {
2451 		err = PTR_ERR(bh);
2452 	} else {
2453 		*credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2454 						    value_len, is_create);
2455 		brelse(bh);
2456 		err = 0;
2457 	}
2458 
2459 	up_read(&EXT4_I(inode)->xattr_sem);
2460 	return err;
2461 }
2462 
2463 /*
2464  * ext4_xattr_set()
2465  *
2466  * Like ext4_xattr_set_handle, but start from an inode. This extended
2467  * attribute modification is a filesystem transaction by itself.
2468  *
2469  * Returns 0, or a negative error number on failure.
2470  */
2471 int
2472 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2473 	       const void *value, size_t value_len, int flags)
2474 {
2475 	handle_t *handle;
2476 	struct super_block *sb = inode->i_sb;
2477 	int error, retries = 0;
2478 	int credits;
2479 
2480 	error = dquot_initialize(inode);
2481 	if (error)
2482 		return error;
2483 
2484 retry:
2485 	error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2486 				       &credits);
2487 	if (error)
2488 		return error;
2489 
2490 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2491 	if (IS_ERR(handle)) {
2492 		error = PTR_ERR(handle);
2493 	} else {
2494 		int error2;
2495 
2496 		error = ext4_xattr_set_handle(handle, inode, name_index, name,
2497 					      value, value_len, flags);
2498 		error2 = ext4_journal_stop(handle);
2499 		if (error == -ENOSPC &&
2500 		    ext4_should_retry_alloc(sb, &retries))
2501 			goto retry;
2502 		if (error == 0)
2503 			error = error2;
2504 	}
2505 	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, NULL);
2506 
2507 	return error;
2508 }
2509 
2510 /*
2511  * Shift the EA entries in the inode to create space for the increased
2512  * i_extra_isize.
2513  */
2514 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2515 				     int value_offs_shift, void *to,
2516 				     void *from, size_t n)
2517 {
2518 	struct ext4_xattr_entry *last = entry;
2519 	int new_offs;
2520 
2521 	/* We always shift xattr headers further thus offsets get lower */
2522 	BUG_ON(value_offs_shift > 0);
2523 
2524 	/* Adjust the value offsets of the entries */
2525 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2526 		if (!last->e_value_inum && last->e_value_size) {
2527 			new_offs = le16_to_cpu(last->e_value_offs) +
2528 							value_offs_shift;
2529 			last->e_value_offs = cpu_to_le16(new_offs);
2530 		}
2531 	}
2532 	/* Shift the entries by n bytes */
2533 	memmove(to, from, n);
2534 }
2535 
2536 /*
2537  * Move xattr pointed to by 'entry' from inode into external xattr block
2538  */
2539 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2540 				    struct ext4_inode *raw_inode,
2541 				    struct ext4_xattr_entry *entry)
2542 {
2543 	struct ext4_xattr_ibody_find *is = NULL;
2544 	struct ext4_xattr_block_find *bs = NULL;
2545 	char *buffer = NULL, *b_entry_name = NULL;
2546 	size_t value_size = le32_to_cpu(entry->e_value_size);
2547 	struct ext4_xattr_info i = {
2548 		.value = NULL,
2549 		.value_len = 0,
2550 		.name_index = entry->e_name_index,
2551 		.in_inode = !!entry->e_value_inum,
2552 	};
2553 	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2554 	int error;
2555 
2556 	is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2557 	bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2558 	buffer = kmalloc(value_size, GFP_NOFS);
2559 	b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2560 	if (!is || !bs || !buffer || !b_entry_name) {
2561 		error = -ENOMEM;
2562 		goto out;
2563 	}
2564 
2565 	is->s.not_found = -ENODATA;
2566 	bs->s.not_found = -ENODATA;
2567 	is->iloc.bh = NULL;
2568 	bs->bh = NULL;
2569 
2570 	/* Save the entry name and the entry value */
2571 	if (entry->e_value_inum) {
2572 		error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2573 		if (error)
2574 			goto out;
2575 	} else {
2576 		size_t value_offs = le16_to_cpu(entry->e_value_offs);
2577 		memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2578 	}
2579 
2580 	memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2581 	b_entry_name[entry->e_name_len] = '\0';
2582 	i.name = b_entry_name;
2583 
2584 	error = ext4_get_inode_loc(inode, &is->iloc);
2585 	if (error)
2586 		goto out;
2587 
2588 	error = ext4_xattr_ibody_find(inode, &i, is);
2589 	if (error)
2590 		goto out;
2591 
2592 	/* Remove the chosen entry from the inode */
2593 	error = ext4_xattr_ibody_set(handle, inode, &i, is);
2594 	if (error)
2595 		goto out;
2596 
2597 	i.value = buffer;
2598 	i.value_len = value_size;
2599 	error = ext4_xattr_block_find(inode, &i, bs);
2600 	if (error)
2601 		goto out;
2602 
2603 	/* Add entry which was removed from the inode into the block */
2604 	error = ext4_xattr_block_set(handle, inode, &i, bs);
2605 	if (error)
2606 		goto out;
2607 	error = 0;
2608 out:
2609 	kfree(b_entry_name);
2610 	kfree(buffer);
2611 	if (is)
2612 		brelse(is->iloc.bh);
2613 	if (bs)
2614 		brelse(bs->bh);
2615 	kfree(is);
2616 	kfree(bs);
2617 
2618 	return error;
2619 }
2620 
2621 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2622 				       struct ext4_inode *raw_inode,
2623 				       int isize_diff, size_t ifree,
2624 				       size_t bfree, int *total_ino)
2625 {
2626 	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2627 	struct ext4_xattr_entry *small_entry;
2628 	struct ext4_xattr_entry *entry;
2629 	struct ext4_xattr_entry *last;
2630 	unsigned int entry_size;	/* EA entry size */
2631 	unsigned int total_size;	/* EA entry size + value size */
2632 	unsigned int min_total_size;
2633 	int error;
2634 
2635 	while (isize_diff > ifree) {
2636 		entry = NULL;
2637 		small_entry = NULL;
2638 		min_total_size = ~0U;
2639 		last = IFIRST(header);
2640 		/* Find the entry best suited to be pushed into EA block */
2641 		for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2642 			/* never move system.data out of the inode */
2643 			if ((last->e_name_len == 4) &&
2644 			    (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2645 			    !memcmp(last->e_name, "data", 4))
2646 				continue;
2647 			total_size = EXT4_XATTR_LEN(last->e_name_len);
2648 			if (!last->e_value_inum)
2649 				total_size += EXT4_XATTR_SIZE(
2650 					       le32_to_cpu(last->e_value_size));
2651 			if (total_size <= bfree &&
2652 			    total_size < min_total_size) {
2653 				if (total_size + ifree < isize_diff) {
2654 					small_entry = last;
2655 				} else {
2656 					entry = last;
2657 					min_total_size = total_size;
2658 				}
2659 			}
2660 		}
2661 
2662 		if (entry == NULL) {
2663 			if (small_entry == NULL)
2664 				return -ENOSPC;
2665 			entry = small_entry;
2666 		}
2667 
2668 		entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2669 		total_size = entry_size;
2670 		if (!entry->e_value_inum)
2671 			total_size += EXT4_XATTR_SIZE(
2672 					      le32_to_cpu(entry->e_value_size));
2673 		error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2674 						 entry);
2675 		if (error)
2676 			return error;
2677 
2678 		*total_ino -= entry_size;
2679 		ifree += total_size;
2680 		bfree -= total_size;
2681 	}
2682 
2683 	return 0;
2684 }
2685 
2686 /*
2687  * Expand an inode by new_extra_isize bytes when EAs are present.
2688  * Returns 0 on success or negative error number on failure.
2689  */
2690 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2691 			       struct ext4_inode *raw_inode, handle_t *handle)
2692 {
2693 	struct ext4_xattr_ibody_header *header;
2694 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2695 	static unsigned int mnt_count;
2696 	size_t min_offs;
2697 	size_t ifree, bfree;
2698 	int total_ino;
2699 	void *base, *end;
2700 	int error = 0, tried_min_extra_isize = 0;
2701 	int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2702 	int isize_diff;	/* How much do we need to grow i_extra_isize */
2703 
2704 retry:
2705 	isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2706 	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2707 		return 0;
2708 
2709 	header = IHDR(inode, raw_inode);
2710 
2711 	/*
2712 	 * Check if enough free space is available in the inode to shift the
2713 	 * entries ahead by new_extra_isize.
2714 	 */
2715 
2716 	base = IFIRST(header);
2717 	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2718 	min_offs = end - base;
2719 	total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2720 
2721 	error = xattr_check_inode(inode, header, end);
2722 	if (error)
2723 		goto cleanup;
2724 
2725 	ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2726 	if (ifree >= isize_diff)
2727 		goto shift;
2728 
2729 	/*
2730 	 * Enough free space isn't available in the inode, check if
2731 	 * EA block can hold new_extra_isize bytes.
2732 	 */
2733 	if (EXT4_I(inode)->i_file_acl) {
2734 		struct buffer_head *bh;
2735 
2736 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2737 		if (IS_ERR(bh)) {
2738 			error = PTR_ERR(bh);
2739 			goto cleanup;
2740 		}
2741 		error = ext4_xattr_check_block(inode, bh);
2742 		if (error) {
2743 			brelse(bh);
2744 			goto cleanup;
2745 		}
2746 		base = BHDR(bh);
2747 		end = bh->b_data + bh->b_size;
2748 		min_offs = end - base;
2749 		bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2750 					      NULL);
2751 		brelse(bh);
2752 		if (bfree + ifree < isize_diff) {
2753 			if (!tried_min_extra_isize && s_min_extra_isize) {
2754 				tried_min_extra_isize++;
2755 				new_extra_isize = s_min_extra_isize;
2756 				goto retry;
2757 			}
2758 			error = -ENOSPC;
2759 			goto cleanup;
2760 		}
2761 	} else {
2762 		bfree = inode->i_sb->s_blocksize;
2763 	}
2764 
2765 	error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2766 					    isize_diff, ifree, bfree,
2767 					    &total_ino);
2768 	if (error) {
2769 		if (error == -ENOSPC && !tried_min_extra_isize &&
2770 		    s_min_extra_isize) {
2771 			tried_min_extra_isize++;
2772 			new_extra_isize = s_min_extra_isize;
2773 			goto retry;
2774 		}
2775 		goto cleanup;
2776 	}
2777 shift:
2778 	/* Adjust the offsets and shift the remaining entries ahead */
2779 	ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2780 			- new_extra_isize, (void *)raw_inode +
2781 			EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2782 			(void *)header, total_ino);
2783 	EXT4_I(inode)->i_extra_isize = new_extra_isize;
2784 
2785 cleanup:
2786 	if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2787 		ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2788 			     inode->i_ino);
2789 		mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2790 	}
2791 	return error;
2792 }
2793 
2794 #define EIA_INCR 16 /* must be 2^n */
2795 #define EIA_MASK (EIA_INCR - 1)
2796 
2797 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2798  * If @ea_inode_array is new or full it will be grown and the old
2799  * contents copied over.
2800  */
2801 static int
2802 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2803 			struct inode *inode)
2804 {
2805 	if (*ea_inode_array == NULL) {
2806 		/*
2807 		 * Start with 15 inodes, so it fits into a power-of-two size.
2808 		 * If *ea_inode_array is NULL, this is essentially offsetof()
2809 		 */
2810 		(*ea_inode_array) =
2811 			kmalloc(offsetof(struct ext4_xattr_inode_array,
2812 					 inodes[EIA_MASK]),
2813 				GFP_NOFS);
2814 		if (*ea_inode_array == NULL)
2815 			return -ENOMEM;
2816 		(*ea_inode_array)->count = 0;
2817 	} else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2818 		/* expand the array once all 15 + n * 16 slots are full */
2819 		struct ext4_xattr_inode_array *new_array = NULL;
2820 		int count = (*ea_inode_array)->count;
2821 
2822 		/* if new_array is NULL, this is essentially offsetof() */
2823 		new_array = kmalloc(
2824 				offsetof(struct ext4_xattr_inode_array,
2825 					 inodes[count + EIA_INCR]),
2826 				GFP_NOFS);
2827 		if (new_array == NULL)
2828 			return -ENOMEM;
2829 		memcpy(new_array, *ea_inode_array,
2830 		       offsetof(struct ext4_xattr_inode_array, inodes[count]));
2831 		kfree(*ea_inode_array);
2832 		*ea_inode_array = new_array;
2833 	}
2834 	(*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2835 	return 0;
2836 }
2837 
2838 /*
2839  * ext4_xattr_delete_inode()
2840  *
2841  * Free extended attribute resources associated with this inode. Traverse
2842  * all entries and decrement reference on any xattr inodes associated with this
2843  * inode. This is called immediately before an inode is freed. We have exclusive
2844  * access to the inode. If an orphan inode is deleted it will also release its
2845  * references on xattr block and xattr inodes.
2846  */
2847 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2848 			    struct ext4_xattr_inode_array **ea_inode_array,
2849 			    int extra_credits)
2850 {
2851 	struct buffer_head *bh = NULL;
2852 	struct ext4_xattr_ibody_header *header;
2853 	struct ext4_iloc iloc = { .bh = NULL };
2854 	struct ext4_xattr_entry *entry;
2855 	struct inode *ea_inode;
2856 	int error;
2857 
2858 	error = ext4_journal_ensure_credits(handle, extra_credits,
2859 			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2860 	if (error < 0) {
2861 		EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2862 		goto cleanup;
2863 	}
2864 
2865 	if (ext4_has_feature_ea_inode(inode->i_sb) &&
2866 	    ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2867 
2868 		error = ext4_get_inode_loc(inode, &iloc);
2869 		if (error) {
2870 			EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2871 			goto cleanup;
2872 		}
2873 
2874 		error = ext4_journal_get_write_access(handle, inode->i_sb,
2875 						iloc.bh, EXT4_JTR_NONE);
2876 		if (error) {
2877 			EXT4_ERROR_INODE(inode, "write access (error %d)",
2878 					 error);
2879 			goto cleanup;
2880 		}
2881 
2882 		header = IHDR(inode, ext4_raw_inode(&iloc));
2883 		if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2884 			ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2885 						     IFIRST(header),
2886 						     false /* block_csum */,
2887 						     ea_inode_array,
2888 						     extra_credits,
2889 						     false /* skip_quota */);
2890 	}
2891 
2892 	if (EXT4_I(inode)->i_file_acl) {
2893 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2894 		if (IS_ERR(bh)) {
2895 			error = PTR_ERR(bh);
2896 			if (error == -EIO) {
2897 				EXT4_ERROR_INODE_ERR(inode, EIO,
2898 						     "block %llu read error",
2899 						     EXT4_I(inode)->i_file_acl);
2900 			}
2901 			bh = NULL;
2902 			goto cleanup;
2903 		}
2904 		error = ext4_xattr_check_block(inode, bh);
2905 		if (error)
2906 			goto cleanup;
2907 
2908 		if (ext4_has_feature_ea_inode(inode->i_sb)) {
2909 			for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2910 			     entry = EXT4_XATTR_NEXT(entry)) {
2911 				if (!entry->e_value_inum)
2912 					continue;
2913 				error = ext4_xattr_inode_iget(inode,
2914 					      le32_to_cpu(entry->e_value_inum),
2915 					      le32_to_cpu(entry->e_hash),
2916 					      &ea_inode);
2917 				if (error)
2918 					continue;
2919 				ext4_xattr_inode_free_quota(inode, ea_inode,
2920 					      le32_to_cpu(entry->e_value_size));
2921 				iput(ea_inode);
2922 			}
2923 
2924 		}
2925 
2926 		ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2927 					 extra_credits);
2928 		/*
2929 		 * Update i_file_acl value in the same transaction that releases
2930 		 * block.
2931 		 */
2932 		EXT4_I(inode)->i_file_acl = 0;
2933 		error = ext4_mark_inode_dirty(handle, inode);
2934 		if (error) {
2935 			EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2936 					 error);
2937 			goto cleanup;
2938 		}
2939 		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2940 	}
2941 	error = 0;
2942 cleanup:
2943 	brelse(iloc.bh);
2944 	brelse(bh);
2945 	return error;
2946 }
2947 
2948 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2949 {
2950 	int idx;
2951 
2952 	if (ea_inode_array == NULL)
2953 		return;
2954 
2955 	for (idx = 0; idx < ea_inode_array->count; ++idx)
2956 		iput(ea_inode_array->inodes[idx]);
2957 	kfree(ea_inode_array);
2958 }
2959 
2960 /*
2961  * ext4_xattr_block_cache_insert()
2962  *
2963  * Create a new entry in the extended attribute block cache, and insert
2964  * it unless such an entry is already in the cache.
2965  *
2966  * Returns 0, or a negative error number on failure.
2967  */
2968 static void
2969 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2970 			      struct buffer_head *bh)
2971 {
2972 	struct ext4_xattr_header *header = BHDR(bh);
2973 	__u32 hash = le32_to_cpu(header->h_hash);
2974 	int reusable = le32_to_cpu(header->h_refcount) <
2975 		       EXT4_XATTR_REFCOUNT_MAX;
2976 	int error;
2977 
2978 	if (!ea_block_cache)
2979 		return;
2980 	error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2981 				      bh->b_blocknr, reusable);
2982 	if (error) {
2983 		if (error == -EBUSY)
2984 			ea_bdebug(bh, "already in cache");
2985 	} else
2986 		ea_bdebug(bh, "inserting [%x]", (int)hash);
2987 }
2988 
2989 /*
2990  * ext4_xattr_cmp()
2991  *
2992  * Compare two extended attribute blocks for equality.
2993  *
2994  * Returns 0 if the blocks are equal, 1 if they differ, and
2995  * a negative error number on errors.
2996  */
2997 static int
2998 ext4_xattr_cmp(struct ext4_xattr_header *header1,
2999 	       struct ext4_xattr_header *header2)
3000 {
3001 	struct ext4_xattr_entry *entry1, *entry2;
3002 
3003 	entry1 = ENTRY(header1+1);
3004 	entry2 = ENTRY(header2+1);
3005 	while (!IS_LAST_ENTRY(entry1)) {
3006 		if (IS_LAST_ENTRY(entry2))
3007 			return 1;
3008 		if (entry1->e_hash != entry2->e_hash ||
3009 		    entry1->e_name_index != entry2->e_name_index ||
3010 		    entry1->e_name_len != entry2->e_name_len ||
3011 		    entry1->e_value_size != entry2->e_value_size ||
3012 		    entry1->e_value_inum != entry2->e_value_inum ||
3013 		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3014 			return 1;
3015 		if (!entry1->e_value_inum &&
3016 		    memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3017 			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3018 			   le32_to_cpu(entry1->e_value_size)))
3019 			return 1;
3020 
3021 		entry1 = EXT4_XATTR_NEXT(entry1);
3022 		entry2 = EXT4_XATTR_NEXT(entry2);
3023 	}
3024 	if (!IS_LAST_ENTRY(entry2))
3025 		return 1;
3026 	return 0;
3027 }
3028 
3029 /*
3030  * ext4_xattr_block_cache_find()
3031  *
3032  * Find an identical extended attribute block.
3033  *
3034  * Returns a pointer to the block found, or NULL if such a block was
3035  * not found or an error occurred.
3036  */
3037 static struct buffer_head *
3038 ext4_xattr_block_cache_find(struct inode *inode,
3039 			    struct ext4_xattr_header *header,
3040 			    struct mb_cache_entry **pce)
3041 {
3042 	__u32 hash = le32_to_cpu(header->h_hash);
3043 	struct mb_cache_entry *ce;
3044 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3045 
3046 	if (!ea_block_cache)
3047 		return NULL;
3048 	if (!header->h_hash)
3049 		return NULL;  /* never share */
3050 	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3051 	ce = mb_cache_entry_find_first(ea_block_cache, hash);
3052 	while (ce) {
3053 		struct buffer_head *bh;
3054 
3055 		bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3056 		if (IS_ERR(bh)) {
3057 			if (PTR_ERR(bh) == -ENOMEM)
3058 				return NULL;
3059 			bh = NULL;
3060 			EXT4_ERROR_INODE(inode, "block %lu read error",
3061 					 (unsigned long)ce->e_value);
3062 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3063 			*pce = ce;
3064 			return bh;
3065 		}
3066 		brelse(bh);
3067 		ce = mb_cache_entry_find_next(ea_block_cache, ce);
3068 	}
3069 	return NULL;
3070 }
3071 
3072 #define NAME_HASH_SHIFT 5
3073 #define VALUE_HASH_SHIFT 16
3074 
3075 /*
3076  * ext4_xattr_hash_entry()
3077  *
3078  * Compute the hash of an extended attribute.
3079  */
3080 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3081 				    size_t value_count)
3082 {
3083 	__u32 hash = 0;
3084 
3085 	while (name_len--) {
3086 		hash = (hash << NAME_HASH_SHIFT) ^
3087 		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3088 		       *name++;
3089 	}
3090 	while (value_count--) {
3091 		hash = (hash << VALUE_HASH_SHIFT) ^
3092 		       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3093 		       le32_to_cpu(*value++);
3094 	}
3095 	return cpu_to_le32(hash);
3096 }
3097 
3098 #undef NAME_HASH_SHIFT
3099 #undef VALUE_HASH_SHIFT
3100 
3101 #define BLOCK_HASH_SHIFT 16
3102 
3103 /*
3104  * ext4_xattr_rehash()
3105  *
3106  * Re-compute the extended attribute hash value after an entry has changed.
3107  */
3108 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3109 {
3110 	struct ext4_xattr_entry *here;
3111 	__u32 hash = 0;
3112 
3113 	here = ENTRY(header+1);
3114 	while (!IS_LAST_ENTRY(here)) {
3115 		if (!here->e_hash) {
3116 			/* Block is not shared if an entry's hash value == 0 */
3117 			hash = 0;
3118 			break;
3119 		}
3120 		hash = (hash << BLOCK_HASH_SHIFT) ^
3121 		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3122 		       le32_to_cpu(here->e_hash);
3123 		here = EXT4_XATTR_NEXT(here);
3124 	}
3125 	header->h_hash = cpu_to_le32(hash);
3126 }
3127 
3128 #undef BLOCK_HASH_SHIFT
3129 
3130 #define	HASH_BUCKET_BITS	10
3131 
3132 struct mb_cache *
3133 ext4_xattr_create_cache(void)
3134 {
3135 	return mb_cache_create(HASH_BUCKET_BITS);
3136 }
3137 
3138 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3139 {
3140 	if (cache)
3141 		mb_cache_destroy(cache);
3142 }
3143 
3144