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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
ext4_xattr_inode_set_class(struct inode * ea_inode)124 void ext4_xattr_inode_set_class(struct inode *ea_inode)
125 {
126 	struct ext4_inode_info *ei = EXT4_I(ea_inode);
127 
128 	lockdep_set_subclass(&ea_inode->i_rwsem, 1);
129 	(void) ei;	/* shut up clang warning if !CONFIG_LOCKDEP */
130 	lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA);
131 }
132 #endif
133 
ext4_xattr_block_csum(struct inode * inode,sector_t block_nr,struct ext4_xattr_header * hdr)134 static __le32 ext4_xattr_block_csum(struct inode *inode,
135 				    sector_t block_nr,
136 				    struct ext4_xattr_header *hdr)
137 {
138 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
139 	__u32 csum;
140 	__le64 dsk_block_nr = cpu_to_le64(block_nr);
141 	__u32 dummy_csum = 0;
142 	int offset = offsetof(struct ext4_xattr_header, h_checksum);
143 
144 	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
145 			   sizeof(dsk_block_nr));
146 	csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
147 	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
148 	offset += sizeof(dummy_csum);
149 	csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
150 			   EXT4_BLOCK_SIZE(inode->i_sb) - offset);
151 
152 	return cpu_to_le32(csum);
153 }
154 
ext4_xattr_block_csum_verify(struct inode * inode,struct buffer_head * bh)155 static int ext4_xattr_block_csum_verify(struct inode *inode,
156 					struct buffer_head *bh)
157 {
158 	struct ext4_xattr_header *hdr = BHDR(bh);
159 	int ret = 1;
160 
161 	if (ext4_has_metadata_csum(inode->i_sb)) {
162 		lock_buffer(bh);
163 		ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
164 							bh->b_blocknr, hdr));
165 		unlock_buffer(bh);
166 	}
167 	return ret;
168 }
169 
ext4_xattr_block_csum_set(struct inode * inode,struct buffer_head * bh)170 static void ext4_xattr_block_csum_set(struct inode *inode,
171 				      struct buffer_head *bh)
172 {
173 	if (ext4_has_metadata_csum(inode->i_sb))
174 		BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
175 						bh->b_blocknr, BHDR(bh));
176 }
177 
178 static inline const struct xattr_handler *
ext4_xattr_handler(int name_index)179 ext4_xattr_handler(int name_index)
180 {
181 	const struct xattr_handler *handler = NULL;
182 
183 	if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
184 		handler = ext4_xattr_handler_map[name_index];
185 	return handler;
186 }
187 
188 static int
ext4_xattr_check_entries(struct ext4_xattr_entry * entry,void * end,void * value_start)189 ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
190 			 void *value_start)
191 {
192 	struct ext4_xattr_entry *e = entry;
193 
194 	/* Find the end of the names list */
195 	while (!IS_LAST_ENTRY(e)) {
196 		struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
197 		if ((void *)next >= end)
198 			return -EFSCORRUPTED;
199 		if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
200 			return -EFSCORRUPTED;
201 		e = next;
202 	}
203 
204 	/* Check the values */
205 	while (!IS_LAST_ENTRY(entry)) {
206 		u32 size = le32_to_cpu(entry->e_value_size);
207 
208 		if (size > EXT4_XATTR_SIZE_MAX)
209 			return -EFSCORRUPTED;
210 
211 		if (size != 0 && entry->e_value_inum == 0) {
212 			u16 offs = le16_to_cpu(entry->e_value_offs);
213 			void *value;
214 
215 			/*
216 			 * The value cannot overlap the names, and the value
217 			 * with padding cannot extend beyond 'end'.  Check both
218 			 * the padded and unpadded sizes, since the size may
219 			 * overflow to 0 when adding padding.
220 			 */
221 			if (offs > end - value_start)
222 				return -EFSCORRUPTED;
223 			value = value_start + offs;
224 			if (value < (void *)e + sizeof(u32) ||
225 			    size > end - value ||
226 			    EXT4_XATTR_SIZE(size) > end - value)
227 				return -EFSCORRUPTED;
228 		}
229 		entry = EXT4_XATTR_NEXT(entry);
230 	}
231 
232 	return 0;
233 }
234 
235 static inline int
__ext4_xattr_check_block(struct inode * inode,struct buffer_head * bh,const char * function,unsigned int line)236 __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
237 			 const char *function, unsigned int line)
238 {
239 	int error = -EFSCORRUPTED;
240 
241 	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
242 	    BHDR(bh)->h_blocks != cpu_to_le32(1))
243 		goto errout;
244 	if (buffer_verified(bh))
245 		return 0;
246 
247 	error = -EFSBADCRC;
248 	if (!ext4_xattr_block_csum_verify(inode, bh))
249 		goto errout;
250 	error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
251 					 bh->b_data);
252 errout:
253 	if (error)
254 		__ext4_error_inode(inode, function, line, 0, -error,
255 				   "corrupted xattr block %llu",
256 				   (unsigned long long) bh->b_blocknr);
257 	else
258 		set_buffer_verified(bh);
259 	return error;
260 }
261 
262 #define ext4_xattr_check_block(inode, bh) \
263 	__ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
264 
265 
266 static int
__xattr_check_inode(struct inode * inode,struct ext4_xattr_ibody_header * header,void * end,const char * function,unsigned int line)267 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
268 			 void *end, const char *function, unsigned int line)
269 {
270 	int error = -EFSCORRUPTED;
271 
272 	if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
273 	    (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
274 		goto errout;
275 	error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
276 errout:
277 	if (error)
278 		__ext4_error_inode(inode, function, line, 0, -error,
279 				   "corrupted in-inode xattr");
280 	return error;
281 }
282 
283 #define xattr_check_inode(inode, header, end) \
284 	__xattr_check_inode((inode), (header), (end), __func__, __LINE__)
285 
286 static int
xattr_find_entry(struct inode * inode,struct ext4_xattr_entry ** pentry,void * end,int name_index,const char * name,int sorted)287 xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
288 		 void *end, int name_index, const char *name, int sorted)
289 {
290 	struct ext4_xattr_entry *entry, *next;
291 	size_t name_len;
292 	int cmp = 1;
293 
294 	if (name == NULL)
295 		return -EINVAL;
296 	name_len = strlen(name);
297 	for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
298 		next = EXT4_XATTR_NEXT(entry);
299 		if ((void *) next >= end) {
300 			EXT4_ERROR_INODE(inode, "corrupted xattr entries");
301 			return -EFSCORRUPTED;
302 		}
303 		cmp = name_index - entry->e_name_index;
304 		if (!cmp)
305 			cmp = name_len - entry->e_name_len;
306 		if (!cmp)
307 			cmp = memcmp(name, entry->e_name, name_len);
308 		if (cmp <= 0 && (sorted || cmp == 0))
309 			break;
310 	}
311 	*pentry = entry;
312 	return cmp ? -ENODATA : 0;
313 }
314 
315 static u32
ext4_xattr_inode_hash(struct ext4_sb_info * sbi,const void * buffer,size_t size)316 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
317 {
318 	return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
319 }
320 
ext4_xattr_inode_get_ref(struct inode * ea_inode)321 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
322 {
323 	return ((u64)ea_inode->i_ctime.tv_sec << 32) |
324 		(u32) inode_peek_iversion_raw(ea_inode);
325 }
326 
ext4_xattr_inode_set_ref(struct inode * ea_inode,u64 ref_count)327 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
328 {
329 	ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
330 	inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
331 }
332 
ext4_xattr_inode_get_hash(struct inode * ea_inode)333 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
334 {
335 	return (u32)ea_inode->i_atime.tv_sec;
336 }
337 
ext4_xattr_inode_set_hash(struct inode * ea_inode,u32 hash)338 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
339 {
340 	ea_inode->i_atime.tv_sec = hash;
341 }
342 
343 /*
344  * Read the EA value from an inode.
345  */
ext4_xattr_inode_read(struct inode * ea_inode,void * buf,size_t size)346 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
347 {
348 	int blocksize = 1 << ea_inode->i_blkbits;
349 	int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
350 	int tail_size = (size % blocksize) ?: blocksize;
351 	struct buffer_head *bhs_inline[8];
352 	struct buffer_head **bhs = bhs_inline;
353 	int i, ret;
354 
355 	if (bh_count > ARRAY_SIZE(bhs_inline)) {
356 		bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
357 		if (!bhs)
358 			return -ENOMEM;
359 	}
360 
361 	ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
362 			       true /* wait */, bhs);
363 	if (ret)
364 		goto free_bhs;
365 
366 	for (i = 0; i < bh_count; i++) {
367 		/* There shouldn't be any holes in ea_inode. */
368 		if (!bhs[i]) {
369 			ret = -EFSCORRUPTED;
370 			goto put_bhs;
371 		}
372 		memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
373 		       i < bh_count - 1 ? blocksize : tail_size);
374 	}
375 	ret = 0;
376 put_bhs:
377 	for (i = 0; i < bh_count; i++)
378 		brelse(bhs[i]);
379 free_bhs:
380 	if (bhs != bhs_inline)
381 		kfree(bhs);
382 	return ret;
383 }
384 
385 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
386 
ext4_xattr_inode_iget(struct inode * parent,unsigned long ea_ino,u32 ea_inode_hash,struct inode ** ea_inode)387 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
388 				 u32 ea_inode_hash, struct inode **ea_inode)
389 {
390 	struct inode *inode;
391 	int err;
392 
393 	/*
394 	 * We have to check for this corruption early as otherwise
395 	 * iget_locked() could wait indefinitely for the state of our
396 	 * parent inode.
397 	 */
398 	if (parent->i_ino == ea_ino) {
399 		ext4_error(parent->i_sb,
400 			   "Parent and EA inode have the same ino %lu", ea_ino);
401 		return -EFSCORRUPTED;
402 	}
403 
404 	inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_EA_INODE);
405 	if (IS_ERR(inode)) {
406 		err = PTR_ERR(inode);
407 		ext4_error(parent->i_sb,
408 			   "error while reading EA inode %lu err=%d", ea_ino,
409 			   err);
410 		return err;
411 	}
412 	ext4_xattr_inode_set_class(inode);
413 
414 	/*
415 	 * Check whether this is an old Lustre-style xattr inode. Lustre
416 	 * implementation does not have hash validation, rather it has a
417 	 * backpointer from ea_inode to the parent inode.
418 	 */
419 	if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
420 	    EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
421 	    inode->i_generation == parent->i_generation) {
422 		ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
423 		ext4_xattr_inode_set_ref(inode, 1);
424 	} else {
425 		inode_lock(inode);
426 		inode->i_flags |= S_NOQUOTA;
427 		inode_unlock(inode);
428 	}
429 
430 	*ea_inode = inode;
431 	return 0;
432 }
433 
434 /* Remove entry from mbcache when EA inode is getting evicted */
ext4_evict_ea_inode(struct inode * inode)435 void ext4_evict_ea_inode(struct inode *inode)
436 {
437 	struct mb_cache_entry *oe;
438 
439 	if (!EA_INODE_CACHE(inode))
440 		return;
441 	/* Wait for entry to get unused so that we can remove it */
442 	while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode),
443 			ext4_xattr_inode_get_hash(inode), inode->i_ino))) {
444 		mb_cache_entry_wait_unused(oe);
445 		mb_cache_entry_put(EA_INODE_CACHE(inode), oe);
446 	}
447 }
448 
449 static int
ext4_xattr_inode_verify_hashes(struct inode * ea_inode,struct ext4_xattr_entry * entry,void * buffer,size_t size)450 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
451 			       struct ext4_xattr_entry *entry, void *buffer,
452 			       size_t size)
453 {
454 	u32 hash;
455 
456 	/* Verify stored hash matches calculated hash. */
457 	hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
458 	if (hash != ext4_xattr_inode_get_hash(ea_inode))
459 		return -EFSCORRUPTED;
460 
461 	if (entry) {
462 		__le32 e_hash, tmp_data;
463 
464 		/* Verify entry hash. */
465 		tmp_data = cpu_to_le32(hash);
466 		e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
467 					       &tmp_data, 1);
468 		if (e_hash != entry->e_hash)
469 			return -EFSCORRUPTED;
470 	}
471 	return 0;
472 }
473 
474 /*
475  * Read xattr value from the EA inode.
476  */
477 static int
ext4_xattr_inode_get(struct inode * inode,struct ext4_xattr_entry * entry,void * buffer,size_t size)478 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
479 		     void *buffer, size_t size)
480 {
481 	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
482 	struct inode *ea_inode;
483 	int err;
484 
485 	err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
486 				    le32_to_cpu(entry->e_hash), &ea_inode);
487 	if (err) {
488 		ea_inode = NULL;
489 		goto out;
490 	}
491 
492 	if (i_size_read(ea_inode) != size) {
493 		ext4_warning_inode(ea_inode,
494 				   "ea_inode file size=%llu entry size=%zu",
495 				   i_size_read(ea_inode), size);
496 		err = -EFSCORRUPTED;
497 		goto out;
498 	}
499 
500 	err = ext4_xattr_inode_read(ea_inode, buffer, size);
501 	if (err)
502 		goto out;
503 
504 	if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
505 		err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
506 						     size);
507 		if (err) {
508 			ext4_warning_inode(ea_inode,
509 					   "EA inode hash validation failed");
510 			goto out;
511 		}
512 
513 		if (ea_inode_cache)
514 			mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
515 					ext4_xattr_inode_get_hash(ea_inode),
516 					ea_inode->i_ino, true /* reusable */);
517 	}
518 out:
519 	iput(ea_inode);
520 	return err;
521 }
522 
523 static int
ext4_xattr_block_get(struct inode * inode,int name_index,const char * name,void * buffer,size_t buffer_size)524 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
525 		     void *buffer, size_t buffer_size)
526 {
527 	struct buffer_head *bh = NULL;
528 	struct ext4_xattr_entry *entry;
529 	size_t size;
530 	void *end;
531 	int error;
532 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
533 
534 	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
535 		  name_index, name, buffer, (long)buffer_size);
536 
537 	if (!EXT4_I(inode)->i_file_acl)
538 		return -ENODATA;
539 	ea_idebug(inode, "reading block %llu",
540 		  (unsigned long long)EXT4_I(inode)->i_file_acl);
541 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
542 	if (IS_ERR(bh))
543 		return PTR_ERR(bh);
544 	ea_bdebug(bh, "b_count=%d, refcount=%d",
545 		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
546 	error = ext4_xattr_check_block(inode, bh);
547 	if (error)
548 		goto cleanup;
549 	ext4_xattr_block_cache_insert(ea_block_cache, bh);
550 	entry = BFIRST(bh);
551 	end = bh->b_data + bh->b_size;
552 	error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
553 	if (error)
554 		goto cleanup;
555 	size = le32_to_cpu(entry->e_value_size);
556 	error = -ERANGE;
557 	if (unlikely(size > EXT4_XATTR_SIZE_MAX))
558 		goto cleanup;
559 	if (buffer) {
560 		if (size > buffer_size)
561 			goto cleanup;
562 		if (entry->e_value_inum) {
563 			error = ext4_xattr_inode_get(inode, entry, buffer,
564 						     size);
565 			if (error)
566 				goto cleanup;
567 		} else {
568 			u16 offset = le16_to_cpu(entry->e_value_offs);
569 			void *p = bh->b_data + offset;
570 
571 			if (unlikely(p + size > end))
572 				goto cleanup;
573 			memcpy(buffer, p, size);
574 		}
575 	}
576 	error = size;
577 
578 cleanup:
579 	brelse(bh);
580 	return error;
581 }
582 
583 int
ext4_xattr_ibody_get(struct inode * inode,int name_index,const char * name,void * buffer,size_t buffer_size)584 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
585 		     void *buffer, size_t buffer_size)
586 {
587 	struct ext4_xattr_ibody_header *header;
588 	struct ext4_xattr_entry *entry;
589 	struct ext4_inode *raw_inode;
590 	struct ext4_iloc iloc;
591 	size_t size;
592 	void *end;
593 	int error;
594 
595 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
596 		return -ENODATA;
597 	error = ext4_get_inode_loc(inode, &iloc);
598 	if (error)
599 		return error;
600 	raw_inode = ext4_raw_inode(&iloc);
601 	header = IHDR(inode, raw_inode);
602 	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
603 	error = xattr_check_inode(inode, header, end);
604 	if (error)
605 		goto cleanup;
606 	entry = IFIRST(header);
607 	error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
608 	if (error)
609 		goto cleanup;
610 	size = le32_to_cpu(entry->e_value_size);
611 	error = -ERANGE;
612 	if (unlikely(size > EXT4_XATTR_SIZE_MAX))
613 		goto cleanup;
614 	if (buffer) {
615 		if (size > buffer_size)
616 			goto cleanup;
617 		if (entry->e_value_inum) {
618 			error = ext4_xattr_inode_get(inode, entry, buffer,
619 						     size);
620 			if (error)
621 				goto cleanup;
622 		} else {
623 			u16 offset = le16_to_cpu(entry->e_value_offs);
624 			void *p = (void *)IFIRST(header) + offset;
625 
626 			if (unlikely(p + size > end))
627 				goto cleanup;
628 			memcpy(buffer, p, size);
629 		}
630 	}
631 	error = size;
632 
633 cleanup:
634 	brelse(iloc.bh);
635 	return error;
636 }
637 
638 /*
639  * ext4_xattr_get()
640  *
641  * Copy an extended attribute into the buffer
642  * provided, or compute the buffer size required.
643  * Buffer is NULL to compute the size of the buffer required.
644  *
645  * Returns a negative error number on failure, or the number of bytes
646  * used / required on success.
647  */
648 int
ext4_xattr_get(struct inode * inode,int name_index,const char * name,void * buffer,size_t buffer_size)649 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
650 	       void *buffer, size_t buffer_size)
651 {
652 	int error;
653 
654 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
655 		return -EIO;
656 
657 	if (strlen(name) > 255)
658 		return -ERANGE;
659 
660 	down_read(&EXT4_I(inode)->xattr_sem);
661 	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
662 				     buffer_size);
663 	if (error == -ENODATA)
664 		error = ext4_xattr_block_get(inode, name_index, name, buffer,
665 					     buffer_size);
666 	up_read(&EXT4_I(inode)->xattr_sem);
667 	return error;
668 }
669 
670 static int
ext4_xattr_list_entries(struct dentry * dentry,struct ext4_xattr_entry * entry,char * buffer,size_t buffer_size)671 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
672 			char *buffer, size_t buffer_size)
673 {
674 	size_t rest = buffer_size;
675 
676 	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
677 		const struct xattr_handler *handler =
678 			ext4_xattr_handler(entry->e_name_index);
679 
680 		if (handler && (!handler->list || handler->list(dentry))) {
681 			const char *prefix = handler->prefix ?: handler->name;
682 			size_t prefix_len = strlen(prefix);
683 			size_t size = prefix_len + entry->e_name_len + 1;
684 
685 			if (buffer) {
686 				if (size > rest)
687 					return -ERANGE;
688 				memcpy(buffer, prefix, prefix_len);
689 				buffer += prefix_len;
690 				memcpy(buffer, entry->e_name, entry->e_name_len);
691 				buffer += entry->e_name_len;
692 				*buffer++ = 0;
693 			}
694 			rest -= size;
695 		}
696 	}
697 	return buffer_size - rest;  /* total size */
698 }
699 
700 static int
ext4_xattr_block_list(struct dentry * dentry,char * buffer,size_t buffer_size)701 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
702 {
703 	struct inode *inode = d_inode(dentry);
704 	struct buffer_head *bh = NULL;
705 	int error;
706 
707 	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
708 		  buffer, (long)buffer_size);
709 
710 	if (!EXT4_I(inode)->i_file_acl)
711 		return 0;
712 	ea_idebug(inode, "reading block %llu",
713 		  (unsigned long long)EXT4_I(inode)->i_file_acl);
714 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
715 	if (IS_ERR(bh))
716 		return PTR_ERR(bh);
717 	ea_bdebug(bh, "b_count=%d, refcount=%d",
718 		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
719 	error = ext4_xattr_check_block(inode, bh);
720 	if (error)
721 		goto cleanup;
722 	ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
723 	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
724 					buffer_size);
725 cleanup:
726 	brelse(bh);
727 	return error;
728 }
729 
730 static int
ext4_xattr_ibody_list(struct dentry * dentry,char * buffer,size_t buffer_size)731 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
732 {
733 	struct inode *inode = d_inode(dentry);
734 	struct ext4_xattr_ibody_header *header;
735 	struct ext4_inode *raw_inode;
736 	struct ext4_iloc iloc;
737 	void *end;
738 	int error;
739 
740 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
741 		return 0;
742 	error = ext4_get_inode_loc(inode, &iloc);
743 	if (error)
744 		return error;
745 	raw_inode = ext4_raw_inode(&iloc);
746 	header = IHDR(inode, raw_inode);
747 	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
748 	error = xattr_check_inode(inode, header, end);
749 	if (error)
750 		goto cleanup;
751 	error = ext4_xattr_list_entries(dentry, IFIRST(header),
752 					buffer, buffer_size);
753 
754 cleanup:
755 	brelse(iloc.bh);
756 	return error;
757 }
758 
759 /*
760  * Inode operation listxattr()
761  *
762  * d_inode(dentry)->i_rwsem: don't care
763  *
764  * Copy a list of attribute names into the buffer
765  * provided, or compute the buffer size required.
766  * Buffer is NULL to compute the size of the buffer required.
767  *
768  * Returns a negative error number on failure, or the number of bytes
769  * used / required on success.
770  */
771 ssize_t
ext4_listxattr(struct dentry * dentry,char * buffer,size_t buffer_size)772 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
773 {
774 	int ret, ret2;
775 
776 	down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
777 	ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
778 	if (ret < 0)
779 		goto errout;
780 	if (buffer) {
781 		buffer += ret;
782 		buffer_size -= ret;
783 	}
784 	ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
785 	if (ret < 0)
786 		goto errout;
787 	ret += ret2;
788 errout:
789 	up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
790 	return ret;
791 }
792 
793 /*
794  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
795  * not set, set it.
796  */
ext4_xattr_update_super_block(handle_t * handle,struct super_block * sb)797 static void ext4_xattr_update_super_block(handle_t *handle,
798 					  struct super_block *sb)
799 {
800 	if (ext4_has_feature_xattr(sb))
801 		return;
802 
803 	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
804 	if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
805 		ext4_set_feature_xattr(sb);
806 		ext4_handle_dirty_super(handle, sb);
807 	}
808 }
809 
ext4_get_inode_usage(struct inode * inode,qsize_t * usage)810 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
811 {
812 	struct ext4_iloc iloc = { .bh = NULL };
813 	struct buffer_head *bh = NULL;
814 	struct ext4_inode *raw_inode;
815 	struct ext4_xattr_ibody_header *header;
816 	struct ext4_xattr_entry *entry;
817 	qsize_t ea_inode_refs = 0;
818 	void *end;
819 	int ret;
820 
821 	lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
822 
823 	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
824 		ret = ext4_get_inode_loc(inode, &iloc);
825 		if (ret)
826 			goto out;
827 		raw_inode = ext4_raw_inode(&iloc);
828 		header = IHDR(inode, raw_inode);
829 		end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
830 		ret = xattr_check_inode(inode, header, end);
831 		if (ret)
832 			goto out;
833 
834 		for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
835 		     entry = EXT4_XATTR_NEXT(entry))
836 			if (entry->e_value_inum)
837 				ea_inode_refs++;
838 	}
839 
840 	if (EXT4_I(inode)->i_file_acl) {
841 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
842 		if (IS_ERR(bh)) {
843 			ret = PTR_ERR(bh);
844 			bh = NULL;
845 			goto out;
846 		}
847 
848 		ret = ext4_xattr_check_block(inode, bh);
849 		if (ret)
850 			goto out;
851 
852 		for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
853 		     entry = EXT4_XATTR_NEXT(entry))
854 			if (entry->e_value_inum)
855 				ea_inode_refs++;
856 	}
857 	*usage = ea_inode_refs + 1;
858 	ret = 0;
859 out:
860 	brelse(iloc.bh);
861 	brelse(bh);
862 	return ret;
863 }
864 
round_up_cluster(struct inode * inode,size_t length)865 static inline size_t round_up_cluster(struct inode *inode, size_t length)
866 {
867 	struct super_block *sb = inode->i_sb;
868 	size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
869 				    inode->i_blkbits);
870 	size_t mask = ~(cluster_size - 1);
871 
872 	return (length + cluster_size - 1) & mask;
873 }
874 
ext4_xattr_inode_alloc_quota(struct inode * inode,size_t len)875 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
876 {
877 	int err;
878 
879 	err = dquot_alloc_inode(inode);
880 	if (err)
881 		return err;
882 	err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
883 	if (err)
884 		dquot_free_inode(inode);
885 	return err;
886 }
887 
ext4_xattr_inode_free_quota(struct inode * parent,struct inode * ea_inode,size_t len)888 static void ext4_xattr_inode_free_quota(struct inode *parent,
889 					struct inode *ea_inode,
890 					size_t len)
891 {
892 	if (ea_inode &&
893 	    ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
894 		return;
895 	dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
896 	dquot_free_inode(parent);
897 }
898 
__ext4_xattr_set_credits(struct super_block * sb,struct inode * inode,struct buffer_head * block_bh,size_t value_len,bool is_create)899 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
900 			     struct buffer_head *block_bh, size_t value_len,
901 			     bool is_create)
902 {
903 	int credits;
904 	int blocks;
905 
906 	/*
907 	 * 1) Owner inode update
908 	 * 2) Ref count update on old xattr block
909 	 * 3) new xattr block
910 	 * 4) block bitmap update for new xattr block
911 	 * 5) group descriptor for new xattr block
912 	 * 6) block bitmap update for old xattr block
913 	 * 7) group descriptor for old block
914 	 *
915 	 * 6 & 7 can happen if we have two racing threads T_a and T_b
916 	 * which are each trying to set an xattr on inodes I_a and I_b
917 	 * which were both initially sharing an xattr block.
918 	 */
919 	credits = 7;
920 
921 	/* Quota updates. */
922 	credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
923 
924 	/*
925 	 * In case of inline data, we may push out the data to a block,
926 	 * so we need to reserve credits for this eventuality
927 	 */
928 	if (inode && ext4_has_inline_data(inode))
929 		credits += ext4_writepage_trans_blocks(inode) + 1;
930 
931 	/* We are done if ea_inode feature is not enabled. */
932 	if (!ext4_has_feature_ea_inode(sb))
933 		return credits;
934 
935 	/* New ea_inode, inode map, block bitmap, group descriptor. */
936 	credits += 4;
937 
938 	/* Data blocks. */
939 	blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
940 
941 	/* Indirection block or one level of extent tree. */
942 	blocks += 1;
943 
944 	/* Block bitmap and group descriptor updates for each block. */
945 	credits += blocks * 2;
946 
947 	/* Blocks themselves. */
948 	credits += blocks;
949 
950 	if (!is_create) {
951 		/* Dereference ea_inode holding old xattr value.
952 		 * Old ea_inode, inode map, block bitmap, group descriptor.
953 		 */
954 		credits += 4;
955 
956 		/* Data blocks for old ea_inode. */
957 		blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
958 
959 		/* Indirection block or one level of extent tree for old
960 		 * ea_inode.
961 		 */
962 		blocks += 1;
963 
964 		/* Block bitmap and group descriptor updates for each block. */
965 		credits += blocks * 2;
966 	}
967 
968 	/* We may need to clone the existing xattr block in which case we need
969 	 * to increment ref counts for existing ea_inodes referenced by it.
970 	 */
971 	if (block_bh) {
972 		struct ext4_xattr_entry *entry = BFIRST(block_bh);
973 
974 		for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
975 			if (entry->e_value_inum)
976 				/* Ref count update on ea_inode. */
977 				credits += 1;
978 	}
979 	return credits;
980 }
981 
ext4_xattr_inode_update_ref(handle_t * handle,struct inode * ea_inode,int ref_change)982 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
983 				       int ref_change)
984 {
985 	struct ext4_iloc iloc;
986 	s64 ref_count;
987 	int ret;
988 
989 	inode_lock(ea_inode);
990 
991 	ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
992 	if (ret)
993 		goto out;
994 
995 	ref_count = ext4_xattr_inode_get_ref(ea_inode);
996 	ref_count += ref_change;
997 	ext4_xattr_inode_set_ref(ea_inode, ref_count);
998 
999 	if (ref_change > 0) {
1000 		WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1001 			  ea_inode->i_ino, ref_count);
1002 
1003 		if (ref_count == 1) {
1004 			WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1005 				  ea_inode->i_ino, ea_inode->i_nlink);
1006 
1007 			set_nlink(ea_inode, 1);
1008 			ext4_orphan_del(handle, ea_inode);
1009 		}
1010 	} else {
1011 		WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1012 			  ea_inode->i_ino, ref_count);
1013 
1014 		if (ref_count == 0) {
1015 			WARN_ONCE(ea_inode->i_nlink != 1,
1016 				  "EA inode %lu i_nlink=%u",
1017 				  ea_inode->i_ino, ea_inode->i_nlink);
1018 
1019 			clear_nlink(ea_inode);
1020 			ext4_orphan_add(handle, ea_inode);
1021 		}
1022 	}
1023 
1024 	ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1025 	if (ret)
1026 		ext4_warning_inode(ea_inode,
1027 				   "ext4_mark_iloc_dirty() failed ret=%d", ret);
1028 out:
1029 	inode_unlock(ea_inode);
1030 	return ret;
1031 }
1032 
ext4_xattr_inode_inc_ref(handle_t * handle,struct inode * ea_inode)1033 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1034 {
1035 	return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1036 }
1037 
ext4_xattr_inode_dec_ref(handle_t * handle,struct inode * ea_inode)1038 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1039 {
1040 	return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1041 }
1042 
ext4_xattr_inode_inc_ref_all(handle_t * handle,struct inode * parent,struct ext4_xattr_entry * first)1043 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1044 					struct ext4_xattr_entry *first)
1045 {
1046 	struct inode *ea_inode;
1047 	struct ext4_xattr_entry *entry;
1048 	struct ext4_xattr_entry *failed_entry;
1049 	unsigned int ea_ino;
1050 	int err, saved_err;
1051 
1052 	for (entry = first; !IS_LAST_ENTRY(entry);
1053 	     entry = EXT4_XATTR_NEXT(entry)) {
1054 		if (!entry->e_value_inum)
1055 			continue;
1056 		ea_ino = le32_to_cpu(entry->e_value_inum);
1057 		err = ext4_xattr_inode_iget(parent, ea_ino,
1058 					    le32_to_cpu(entry->e_hash),
1059 					    &ea_inode);
1060 		if (err)
1061 			goto cleanup;
1062 		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1063 		if (err) {
1064 			ext4_warning_inode(ea_inode, "inc ref error %d", err);
1065 			iput(ea_inode);
1066 			goto cleanup;
1067 		}
1068 		iput(ea_inode);
1069 	}
1070 	return 0;
1071 
1072 cleanup:
1073 	saved_err = err;
1074 	failed_entry = entry;
1075 
1076 	for (entry = first; entry != failed_entry;
1077 	     entry = EXT4_XATTR_NEXT(entry)) {
1078 		if (!entry->e_value_inum)
1079 			continue;
1080 		ea_ino = le32_to_cpu(entry->e_value_inum);
1081 		err = ext4_xattr_inode_iget(parent, ea_ino,
1082 					    le32_to_cpu(entry->e_hash),
1083 					    &ea_inode);
1084 		if (err) {
1085 			ext4_warning(parent->i_sb,
1086 				     "cleanup ea_ino %u iget error %d", ea_ino,
1087 				     err);
1088 			continue;
1089 		}
1090 		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1091 		if (err)
1092 			ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1093 					   err);
1094 		iput(ea_inode);
1095 	}
1096 	return saved_err;
1097 }
1098 
ext4_xattr_restart_fn(handle_t * handle,struct inode * inode,struct buffer_head * bh,bool block_csum,bool dirty)1099 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1100 			struct buffer_head *bh, bool block_csum, bool dirty)
1101 {
1102 	int error;
1103 
1104 	if (bh && dirty) {
1105 		if (block_csum)
1106 			ext4_xattr_block_csum_set(inode, bh);
1107 		error = ext4_handle_dirty_metadata(handle, NULL, bh);
1108 		if (error) {
1109 			ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1110 				     error);
1111 			return error;
1112 		}
1113 	}
1114 	return 0;
1115 }
1116 
1117 static void
ext4_xattr_inode_dec_ref_all(handle_t * handle,struct inode * parent,struct buffer_head * bh,struct ext4_xattr_entry * first,bool block_csum,struct ext4_xattr_inode_array ** ea_inode_array,int extra_credits,bool skip_quota)1118 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1119 			     struct buffer_head *bh,
1120 			     struct ext4_xattr_entry *first, bool block_csum,
1121 			     struct ext4_xattr_inode_array **ea_inode_array,
1122 			     int extra_credits, bool skip_quota)
1123 {
1124 	struct inode *ea_inode;
1125 	struct ext4_xattr_entry *entry;
1126 	bool dirty = false;
1127 	unsigned int ea_ino;
1128 	int err;
1129 	int credits;
1130 
1131 	/* One credit for dec ref on ea_inode, one for orphan list addition, */
1132 	credits = 2 + extra_credits;
1133 
1134 	for (entry = first; !IS_LAST_ENTRY(entry);
1135 	     entry = EXT4_XATTR_NEXT(entry)) {
1136 		if (!entry->e_value_inum)
1137 			continue;
1138 		ea_ino = le32_to_cpu(entry->e_value_inum);
1139 		err = ext4_xattr_inode_iget(parent, ea_ino,
1140 					    le32_to_cpu(entry->e_hash),
1141 					    &ea_inode);
1142 		if (err)
1143 			continue;
1144 
1145 		err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1146 		if (err) {
1147 			ext4_warning_inode(ea_inode,
1148 					   "Expand inode array err=%d", err);
1149 			iput(ea_inode);
1150 			continue;
1151 		}
1152 
1153 		err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1154 			ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1155 			ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1156 					      dirty));
1157 		if (err < 0) {
1158 			ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1159 					   err);
1160 			continue;
1161 		}
1162 		if (err > 0) {
1163 			err = ext4_journal_get_write_access(handle, bh);
1164 			if (err) {
1165 				ext4_warning_inode(ea_inode,
1166 						"Re-get write access err=%d",
1167 						err);
1168 				continue;
1169 			}
1170 		}
1171 
1172 		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1173 		if (err) {
1174 			ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1175 					   err);
1176 			continue;
1177 		}
1178 
1179 		if (!skip_quota)
1180 			ext4_xattr_inode_free_quota(parent, ea_inode,
1181 					      le32_to_cpu(entry->e_value_size));
1182 
1183 		/*
1184 		 * Forget about ea_inode within the same transaction that
1185 		 * decrements the ref count. This avoids duplicate decrements in
1186 		 * case the rest of the work spills over to subsequent
1187 		 * transactions.
1188 		 */
1189 		entry->e_value_inum = 0;
1190 		entry->e_value_size = 0;
1191 
1192 		dirty = true;
1193 	}
1194 
1195 	if (dirty) {
1196 		/*
1197 		 * Note that we are deliberately skipping csum calculation for
1198 		 * the final update because we do not expect any journal
1199 		 * restarts until xattr block is freed.
1200 		 */
1201 
1202 		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1203 		if (err)
1204 			ext4_warning_inode(parent,
1205 					   "handle dirty metadata err=%d", err);
1206 	}
1207 }
1208 
1209 /*
1210  * Release the xattr block BH: If the reference count is > 1, decrement it;
1211  * otherwise free the block.
1212  */
1213 static void
ext4_xattr_release_block(handle_t * handle,struct inode * inode,struct buffer_head * bh,struct ext4_xattr_inode_array ** ea_inode_array,int extra_credits)1214 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1215 			 struct buffer_head *bh,
1216 			 struct ext4_xattr_inode_array **ea_inode_array,
1217 			 int extra_credits)
1218 {
1219 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1220 	u32 hash, ref;
1221 	int error = 0;
1222 
1223 	BUFFER_TRACE(bh, "get_write_access");
1224 	error = ext4_journal_get_write_access(handle, bh);
1225 	if (error)
1226 		goto out;
1227 
1228 retry_ref:
1229 	lock_buffer(bh);
1230 	hash = le32_to_cpu(BHDR(bh)->h_hash);
1231 	ref = le32_to_cpu(BHDR(bh)->h_refcount);
1232 	if (ref == 1) {
1233 		ea_bdebug(bh, "refcount now=0; freeing");
1234 		/*
1235 		 * This must happen under buffer lock for
1236 		 * ext4_xattr_block_set() to reliably detect freed block
1237 		 */
1238 		if (ea_block_cache) {
1239 			struct mb_cache_entry *oe;
1240 
1241 			oe = mb_cache_entry_delete_or_get(ea_block_cache, hash,
1242 							  bh->b_blocknr);
1243 			if (oe) {
1244 				unlock_buffer(bh);
1245 				mb_cache_entry_wait_unused(oe);
1246 				mb_cache_entry_put(ea_block_cache, oe);
1247 				goto retry_ref;
1248 			}
1249 		}
1250 		get_bh(bh);
1251 		unlock_buffer(bh);
1252 
1253 		if (ext4_has_feature_ea_inode(inode->i_sb))
1254 			ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1255 						     BFIRST(bh),
1256 						     true /* block_csum */,
1257 						     ea_inode_array,
1258 						     extra_credits,
1259 						     true /* skip_quota */);
1260 		ext4_free_blocks(handle, inode, bh, 0, 1,
1261 				 EXT4_FREE_BLOCKS_METADATA |
1262 				 EXT4_FREE_BLOCKS_FORGET);
1263 	} else {
1264 		ref--;
1265 		BHDR(bh)->h_refcount = cpu_to_le32(ref);
1266 		if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1267 			struct mb_cache_entry *ce;
1268 
1269 			if (ea_block_cache) {
1270 				ce = mb_cache_entry_get(ea_block_cache, hash,
1271 							bh->b_blocknr);
1272 				if (ce) {
1273 					set_bit(MBE_REUSABLE_B, &ce->e_flags);
1274 					mb_cache_entry_put(ea_block_cache, ce);
1275 				}
1276 			}
1277 		}
1278 
1279 		ext4_xattr_block_csum_set(inode, bh);
1280 		/*
1281 		 * Beware of this ugliness: Releasing of xattr block references
1282 		 * from different inodes can race and so we have to protect
1283 		 * from a race where someone else frees the block (and releases
1284 		 * its journal_head) before we are done dirtying the buffer. In
1285 		 * nojournal mode this race is harmless and we actually cannot
1286 		 * call ext4_handle_dirty_metadata() with locked buffer as
1287 		 * that function can call sync_dirty_buffer() so for that case
1288 		 * we handle the dirtying after unlocking the buffer.
1289 		 */
1290 		if (ext4_handle_valid(handle))
1291 			error = ext4_handle_dirty_metadata(handle, inode, bh);
1292 		unlock_buffer(bh);
1293 		if (!ext4_handle_valid(handle))
1294 			error = ext4_handle_dirty_metadata(handle, inode, bh);
1295 		if (IS_SYNC(inode))
1296 			ext4_handle_sync(handle);
1297 		dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1298 		ea_bdebug(bh, "refcount now=%d; releasing",
1299 			  le32_to_cpu(BHDR(bh)->h_refcount));
1300 	}
1301 out:
1302 	ext4_std_error(inode->i_sb, error);
1303 	return;
1304 }
1305 
1306 /*
1307  * Find the available free space for EAs. This also returns the total number of
1308  * bytes used by EA entries.
1309  */
ext4_xattr_free_space(struct ext4_xattr_entry * last,size_t * min_offs,void * base,int * total)1310 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1311 				    size_t *min_offs, void *base, int *total)
1312 {
1313 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1314 		if (!last->e_value_inum && last->e_value_size) {
1315 			size_t offs = le16_to_cpu(last->e_value_offs);
1316 			if (offs < *min_offs)
1317 				*min_offs = offs;
1318 		}
1319 		if (total)
1320 			*total += EXT4_XATTR_LEN(last->e_name_len);
1321 	}
1322 	return (*min_offs - ((void *)last - base) - sizeof(__u32));
1323 }
1324 
1325 /*
1326  * Write the value of the EA in an inode.
1327  */
ext4_xattr_inode_write(handle_t * handle,struct inode * ea_inode,const void * buf,int bufsize)1328 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1329 				  const void *buf, int bufsize)
1330 {
1331 	struct buffer_head *bh = NULL;
1332 	unsigned long block = 0;
1333 	int blocksize = ea_inode->i_sb->s_blocksize;
1334 	int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1335 	int csize, wsize = 0;
1336 	int ret = 0, ret2 = 0;
1337 	int retries = 0;
1338 
1339 retry:
1340 	while (ret >= 0 && ret < max_blocks) {
1341 		struct ext4_map_blocks map;
1342 		map.m_lblk = block += ret;
1343 		map.m_len = max_blocks -= ret;
1344 
1345 		ret = ext4_map_blocks(handle, ea_inode, &map,
1346 				      EXT4_GET_BLOCKS_CREATE);
1347 		if (ret <= 0) {
1348 			ext4_mark_inode_dirty(handle, ea_inode);
1349 			if (ret == -ENOSPC &&
1350 			    ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1351 				ret = 0;
1352 				goto retry;
1353 			}
1354 			break;
1355 		}
1356 	}
1357 
1358 	if (ret < 0)
1359 		return ret;
1360 
1361 	block = 0;
1362 	while (wsize < bufsize) {
1363 		brelse(bh);
1364 		csize = (bufsize - wsize) > blocksize ? blocksize :
1365 								bufsize - wsize;
1366 		bh = ext4_getblk(handle, ea_inode, block, 0);
1367 		if (IS_ERR(bh))
1368 			return PTR_ERR(bh);
1369 		if (!bh) {
1370 			WARN_ON_ONCE(1);
1371 			EXT4_ERROR_INODE(ea_inode,
1372 					 "ext4_getblk() return bh = NULL");
1373 			return -EFSCORRUPTED;
1374 		}
1375 		ret = ext4_journal_get_write_access(handle, bh);
1376 		if (ret)
1377 			goto out;
1378 
1379 		memcpy(bh->b_data, buf, csize);
1380 		set_buffer_uptodate(bh);
1381 		ext4_handle_dirty_metadata(handle, ea_inode, bh);
1382 
1383 		buf += csize;
1384 		wsize += csize;
1385 		block += 1;
1386 	}
1387 
1388 	inode_lock(ea_inode);
1389 	i_size_write(ea_inode, wsize);
1390 	ext4_update_i_disksize(ea_inode, wsize);
1391 	inode_unlock(ea_inode);
1392 
1393 	ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1394 	if (unlikely(ret2 && !ret))
1395 		ret = ret2;
1396 
1397 out:
1398 	brelse(bh);
1399 
1400 	return ret;
1401 }
1402 
1403 /*
1404  * Create an inode to store the value of a large EA.
1405  */
ext4_xattr_inode_create(handle_t * handle,struct inode * inode,u32 hash)1406 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1407 					     struct inode *inode, u32 hash)
1408 {
1409 	struct inode *ea_inode = NULL;
1410 	uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1411 	int err;
1412 
1413 	if (inode->i_sb->s_root == NULL) {
1414 		ext4_warning(inode->i_sb,
1415 			     "refuse to create EA inode when umounting");
1416 		WARN_ON(1);
1417 		return ERR_PTR(-EINVAL);
1418 	}
1419 
1420 	/*
1421 	 * Let the next inode be the goal, so we try and allocate the EA inode
1422 	 * in the same group, or nearby one.
1423 	 */
1424 	ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1425 				  S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1426 				  EXT4_EA_INODE_FL);
1427 	if (!IS_ERR(ea_inode)) {
1428 		ea_inode->i_op = &ext4_file_inode_operations;
1429 		ea_inode->i_fop = &ext4_file_operations;
1430 		ext4_set_aops(ea_inode);
1431 		ext4_xattr_inode_set_class(ea_inode);
1432 		unlock_new_inode(ea_inode);
1433 		ext4_xattr_inode_set_ref(ea_inode, 1);
1434 		ext4_xattr_inode_set_hash(ea_inode, hash);
1435 		err = ext4_mark_inode_dirty(handle, ea_inode);
1436 		if (!err)
1437 			err = ext4_inode_attach_jinode(ea_inode);
1438 		if (err) {
1439 			if (ext4_xattr_inode_dec_ref(handle, ea_inode))
1440 				ext4_warning_inode(ea_inode,
1441 					"cleanup dec ref error %d", err);
1442 			iput(ea_inode);
1443 			return ERR_PTR(err);
1444 		}
1445 
1446 		/*
1447 		 * Xattr inodes are shared therefore quota charging is performed
1448 		 * at a higher level.
1449 		 */
1450 		dquot_free_inode(ea_inode);
1451 		dquot_drop(ea_inode);
1452 		inode_lock(ea_inode);
1453 		ea_inode->i_flags |= S_NOQUOTA;
1454 		inode_unlock(ea_inode);
1455 	}
1456 
1457 	return ea_inode;
1458 }
1459 
1460 static struct inode *
ext4_xattr_inode_cache_find(struct inode * inode,const void * value,size_t value_len,u32 hash)1461 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1462 			    size_t value_len, u32 hash)
1463 {
1464 	struct inode *ea_inode;
1465 	struct mb_cache_entry *ce;
1466 	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1467 	void *ea_data;
1468 
1469 	if (!ea_inode_cache)
1470 		return NULL;
1471 
1472 	ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1473 	if (!ce)
1474 		return NULL;
1475 
1476 	WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1477 		     !(current->flags & PF_MEMALLOC_NOFS));
1478 
1479 	ea_data = kvmalloc(value_len, GFP_KERNEL);
1480 	if (!ea_data) {
1481 		mb_cache_entry_put(ea_inode_cache, ce);
1482 		return NULL;
1483 	}
1484 
1485 	while (ce) {
1486 		ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1487 				     EXT4_IGET_EA_INODE);
1488 		if (IS_ERR(ea_inode))
1489 			goto next_entry;
1490 		ext4_xattr_inode_set_class(ea_inode);
1491 		if (i_size_read(ea_inode) == value_len &&
1492 		    !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1493 		    !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1494 						    value_len) &&
1495 		    !memcmp(value, ea_data, value_len)) {
1496 			mb_cache_entry_touch(ea_inode_cache, ce);
1497 			mb_cache_entry_put(ea_inode_cache, ce);
1498 			kvfree(ea_data);
1499 			return ea_inode;
1500 		}
1501 		iput(ea_inode);
1502 	next_entry:
1503 		ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1504 	}
1505 	kvfree(ea_data);
1506 	return NULL;
1507 }
1508 
1509 /*
1510  * Add value of the EA in an inode.
1511  */
ext4_xattr_inode_lookup_create(handle_t * handle,struct inode * inode,const void * value,size_t value_len,struct inode ** ret_inode)1512 static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1513 					  const void *value, size_t value_len,
1514 					  struct inode **ret_inode)
1515 {
1516 	struct inode *ea_inode;
1517 	u32 hash;
1518 	int err;
1519 
1520 	hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1521 	ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1522 	if (ea_inode) {
1523 		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1524 		if (err) {
1525 			iput(ea_inode);
1526 			return err;
1527 		}
1528 
1529 		*ret_inode = ea_inode;
1530 		return 0;
1531 	}
1532 
1533 	/* Create an inode for the EA value */
1534 	ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1535 	if (IS_ERR(ea_inode))
1536 		return PTR_ERR(ea_inode);
1537 
1538 	err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1539 	if (err) {
1540 		ext4_xattr_inode_dec_ref(handle, ea_inode);
1541 		iput(ea_inode);
1542 		return err;
1543 	}
1544 
1545 	if (EA_INODE_CACHE(inode))
1546 		mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1547 				      ea_inode->i_ino, true /* reusable */);
1548 
1549 	*ret_inode = ea_inode;
1550 	return 0;
1551 }
1552 
1553 /*
1554  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1555  * feature is enabled.
1556  */
1557 #define EXT4_XATTR_BLOCK_RESERVE(inode)	min(i_blocksize(inode)/8, 1024U)
1558 
ext4_xattr_set_entry(struct ext4_xattr_info * i,struct ext4_xattr_search * s,handle_t * handle,struct inode * inode,bool is_block)1559 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1560 				struct ext4_xattr_search *s,
1561 				handle_t *handle, struct inode *inode,
1562 				bool is_block)
1563 {
1564 	struct ext4_xattr_entry *last, *next;
1565 	struct ext4_xattr_entry *here = s->here;
1566 	size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1567 	int in_inode = i->in_inode;
1568 	struct inode *old_ea_inode = NULL;
1569 	struct inode *new_ea_inode = NULL;
1570 	size_t old_size, new_size;
1571 	int ret;
1572 
1573 	/* Space used by old and new values. */
1574 	old_size = (!s->not_found && !here->e_value_inum) ?
1575 			EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1576 	new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1577 
1578 	/*
1579 	 * Optimization for the simple case when old and new values have the
1580 	 * same padded sizes. Not applicable if external inodes are involved.
1581 	 */
1582 	if (new_size && new_size == old_size) {
1583 		size_t offs = le16_to_cpu(here->e_value_offs);
1584 		void *val = s->base + offs;
1585 
1586 		here->e_value_size = cpu_to_le32(i->value_len);
1587 		if (i->value == EXT4_ZERO_XATTR_VALUE) {
1588 			memset(val, 0, new_size);
1589 		} else {
1590 			memcpy(val, i->value, i->value_len);
1591 			/* Clear padding bytes. */
1592 			memset(val + i->value_len, 0, new_size - i->value_len);
1593 		}
1594 		goto update_hash;
1595 	}
1596 
1597 	/* Compute min_offs and last. */
1598 	last = s->first;
1599 	for (; !IS_LAST_ENTRY(last); last = next) {
1600 		next = EXT4_XATTR_NEXT(last);
1601 		if ((void *)next >= s->end) {
1602 			EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1603 			ret = -EFSCORRUPTED;
1604 			goto out;
1605 		}
1606 		if (!last->e_value_inum && last->e_value_size) {
1607 			size_t offs = le16_to_cpu(last->e_value_offs);
1608 			if (offs < min_offs)
1609 				min_offs = offs;
1610 		}
1611 	}
1612 
1613 	/* Check whether we have enough space. */
1614 	if (i->value) {
1615 		size_t free;
1616 
1617 		free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1618 		if (!s->not_found)
1619 			free += EXT4_XATTR_LEN(name_len) + old_size;
1620 
1621 		if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1622 			ret = -ENOSPC;
1623 			goto out;
1624 		}
1625 
1626 		/*
1627 		 * If storing the value in an external inode is an option,
1628 		 * reserve space for xattr entries/names in the external
1629 		 * attribute block so that a long value does not occupy the
1630 		 * whole space and prevent further entries being added.
1631 		 */
1632 		if (ext4_has_feature_ea_inode(inode->i_sb) &&
1633 		    new_size && is_block &&
1634 		    (min_offs + old_size - new_size) <
1635 					EXT4_XATTR_BLOCK_RESERVE(inode)) {
1636 			ret = -ENOSPC;
1637 			goto out;
1638 		}
1639 	}
1640 
1641 	/*
1642 	 * Getting access to old and new ea inodes is subject to failures.
1643 	 * Finish that work before doing any modifications to the xattr data.
1644 	 */
1645 	if (!s->not_found && here->e_value_inum) {
1646 		ret = ext4_xattr_inode_iget(inode,
1647 					    le32_to_cpu(here->e_value_inum),
1648 					    le32_to_cpu(here->e_hash),
1649 					    &old_ea_inode);
1650 		if (ret) {
1651 			old_ea_inode = NULL;
1652 			goto out;
1653 		}
1654 	}
1655 	if (i->value && in_inode) {
1656 		WARN_ON_ONCE(!i->value_len);
1657 
1658 		ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1659 		if (ret)
1660 			goto out;
1661 
1662 		ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1663 						     i->value_len,
1664 						     &new_ea_inode);
1665 		if (ret) {
1666 			new_ea_inode = NULL;
1667 			ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1668 			goto out;
1669 		}
1670 	}
1671 
1672 	if (old_ea_inode) {
1673 		/* We are ready to release ref count on the old_ea_inode. */
1674 		ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1675 		if (ret) {
1676 			/* Release newly required ref count on new_ea_inode. */
1677 			if (new_ea_inode) {
1678 				int err;
1679 
1680 				err = ext4_xattr_inode_dec_ref(handle,
1681 							       new_ea_inode);
1682 				if (err)
1683 					ext4_warning_inode(new_ea_inode,
1684 						  "dec ref new_ea_inode err=%d",
1685 						  err);
1686 				ext4_xattr_inode_free_quota(inode, new_ea_inode,
1687 							    i->value_len);
1688 			}
1689 			goto out;
1690 		}
1691 
1692 		ext4_xattr_inode_free_quota(inode, old_ea_inode,
1693 					    le32_to_cpu(here->e_value_size));
1694 	}
1695 
1696 	/* No failures allowed past this point. */
1697 
1698 	if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1699 		/* Remove the old value. */
1700 		void *first_val = s->base + min_offs;
1701 		size_t offs = le16_to_cpu(here->e_value_offs);
1702 		void *val = s->base + offs;
1703 
1704 		memmove(first_val + old_size, first_val, val - first_val);
1705 		memset(first_val, 0, old_size);
1706 		min_offs += old_size;
1707 
1708 		/* Adjust all value offsets. */
1709 		last = s->first;
1710 		while (!IS_LAST_ENTRY(last)) {
1711 			size_t o = le16_to_cpu(last->e_value_offs);
1712 
1713 			if (!last->e_value_inum &&
1714 			    last->e_value_size && o < offs)
1715 				last->e_value_offs = cpu_to_le16(o + old_size);
1716 			last = EXT4_XATTR_NEXT(last);
1717 		}
1718 	}
1719 
1720 	if (!i->value) {
1721 		/* Remove old name. */
1722 		size_t size = EXT4_XATTR_LEN(name_len);
1723 
1724 		last = ENTRY((void *)last - size);
1725 		memmove(here, (void *)here + size,
1726 			(void *)last - (void *)here + sizeof(__u32));
1727 		memset(last, 0, size);
1728 
1729 		/*
1730 		 * Update i_inline_off - moved ibody region might contain
1731 		 * system.data attribute.  Handling a failure here won't
1732 		 * cause other complications for setting an xattr.
1733 		 */
1734 		if (!is_block && ext4_has_inline_data(inode)) {
1735 			ret = ext4_find_inline_data_nolock(inode);
1736 			if (ret) {
1737 				ext4_warning_inode(inode,
1738 					"unable to update i_inline_off");
1739 				goto out;
1740 			}
1741 		}
1742 	} else if (s->not_found) {
1743 		/* Insert new name. */
1744 		size_t size = EXT4_XATTR_LEN(name_len);
1745 		size_t rest = (void *)last - (void *)here + sizeof(__u32);
1746 
1747 		memmove((void *)here + size, here, rest);
1748 		memset(here, 0, size);
1749 		here->e_name_index = i->name_index;
1750 		here->e_name_len = name_len;
1751 		memcpy(here->e_name, i->name, name_len);
1752 	} else {
1753 		/* This is an update, reset value info. */
1754 		here->e_value_inum = 0;
1755 		here->e_value_offs = 0;
1756 		here->e_value_size = 0;
1757 	}
1758 
1759 	if (i->value) {
1760 		/* Insert new value. */
1761 		if (in_inode) {
1762 			here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1763 		} else if (i->value_len) {
1764 			void *val = s->base + min_offs - new_size;
1765 
1766 			here->e_value_offs = cpu_to_le16(min_offs - new_size);
1767 			if (i->value == EXT4_ZERO_XATTR_VALUE) {
1768 				memset(val, 0, new_size);
1769 			} else {
1770 				memcpy(val, i->value, i->value_len);
1771 				/* Clear padding bytes. */
1772 				memset(val + i->value_len, 0,
1773 				       new_size - i->value_len);
1774 			}
1775 		}
1776 		here->e_value_size = cpu_to_le32(i->value_len);
1777 	}
1778 
1779 update_hash:
1780 	if (i->value) {
1781 		__le32 hash = 0;
1782 
1783 		/* Entry hash calculation. */
1784 		if (in_inode) {
1785 			__le32 crc32c_hash;
1786 
1787 			/*
1788 			 * Feed crc32c hash instead of the raw value for entry
1789 			 * hash calculation. This is to avoid walking
1790 			 * potentially long value buffer again.
1791 			 */
1792 			crc32c_hash = cpu_to_le32(
1793 				       ext4_xattr_inode_get_hash(new_ea_inode));
1794 			hash = ext4_xattr_hash_entry(here->e_name,
1795 						     here->e_name_len,
1796 						     &crc32c_hash, 1);
1797 		} else if (is_block) {
1798 			__le32 *value = s->base + le16_to_cpu(
1799 							here->e_value_offs);
1800 
1801 			hash = ext4_xattr_hash_entry(here->e_name,
1802 						     here->e_name_len, value,
1803 						     new_size >> 2);
1804 		}
1805 		here->e_hash = hash;
1806 	}
1807 
1808 	if (is_block)
1809 		ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1810 
1811 	ret = 0;
1812 out:
1813 	iput(old_ea_inode);
1814 	iput(new_ea_inode);
1815 	return ret;
1816 }
1817 
1818 struct ext4_xattr_block_find {
1819 	struct ext4_xattr_search s;
1820 	struct buffer_head *bh;
1821 };
1822 
1823 static int
ext4_xattr_block_find(struct inode * inode,struct ext4_xattr_info * i,struct ext4_xattr_block_find * bs)1824 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1825 		      struct ext4_xattr_block_find *bs)
1826 {
1827 	struct super_block *sb = inode->i_sb;
1828 	int error;
1829 
1830 	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1831 		  i->name_index, i->name, i->value, (long)i->value_len);
1832 
1833 	if (EXT4_I(inode)->i_file_acl) {
1834 		/* The inode already has an extended attribute block. */
1835 		bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1836 		if (IS_ERR(bs->bh)) {
1837 			error = PTR_ERR(bs->bh);
1838 			bs->bh = NULL;
1839 			return error;
1840 		}
1841 		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1842 			atomic_read(&(bs->bh->b_count)),
1843 			le32_to_cpu(BHDR(bs->bh)->h_refcount));
1844 		error = ext4_xattr_check_block(inode, bs->bh);
1845 		if (error)
1846 			return error;
1847 		/* Find the named attribute. */
1848 		bs->s.base = BHDR(bs->bh);
1849 		bs->s.first = BFIRST(bs->bh);
1850 		bs->s.end = bs->bh->b_data + bs->bh->b_size;
1851 		bs->s.here = bs->s.first;
1852 		error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1853 					 i->name_index, i->name, 1);
1854 		if (error && error != -ENODATA)
1855 			return error;
1856 		bs->s.not_found = error;
1857 	}
1858 	return 0;
1859 }
1860 
1861 static int
ext4_xattr_block_set(handle_t * handle,struct inode * inode,struct ext4_xattr_info * i,struct ext4_xattr_block_find * bs)1862 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1863 		     struct ext4_xattr_info *i,
1864 		     struct ext4_xattr_block_find *bs)
1865 {
1866 	struct super_block *sb = inode->i_sb;
1867 	struct buffer_head *new_bh = NULL;
1868 	struct ext4_xattr_search s_copy = bs->s;
1869 	struct ext4_xattr_search *s = &s_copy;
1870 	struct mb_cache_entry *ce = NULL;
1871 	int error = 0;
1872 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1873 	struct inode *ea_inode = NULL, *tmp_inode;
1874 	size_t old_ea_inode_quota = 0;
1875 	unsigned int ea_ino;
1876 
1877 
1878 #define header(x) ((struct ext4_xattr_header *)(x))
1879 
1880 	if (s->base) {
1881 		int offset = (char *)s->here - bs->bh->b_data;
1882 
1883 		BUFFER_TRACE(bs->bh, "get_write_access");
1884 		error = ext4_journal_get_write_access(handle, bs->bh);
1885 		if (error)
1886 			goto cleanup;
1887 		lock_buffer(bs->bh);
1888 
1889 		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1890 			__u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1891 
1892 			/*
1893 			 * This must happen under buffer lock for
1894 			 * ext4_xattr_block_set() to reliably detect modified
1895 			 * block
1896 			 */
1897 			if (ea_block_cache) {
1898 				struct mb_cache_entry *oe;
1899 
1900 				oe = mb_cache_entry_delete_or_get(ea_block_cache,
1901 					hash, bs->bh->b_blocknr);
1902 				if (oe) {
1903 					/*
1904 					 * Xattr block is getting reused. Leave
1905 					 * it alone.
1906 					 */
1907 					mb_cache_entry_put(ea_block_cache, oe);
1908 					goto clone_block;
1909 				}
1910 			}
1911 			ea_bdebug(bs->bh, "modifying in-place");
1912 			error = ext4_xattr_set_entry(i, s, handle, inode,
1913 						     true /* is_block */);
1914 			ext4_xattr_block_csum_set(inode, bs->bh);
1915 			unlock_buffer(bs->bh);
1916 			if (error == -EFSCORRUPTED)
1917 				goto bad_block;
1918 			if (!error)
1919 				error = ext4_handle_dirty_metadata(handle,
1920 								   inode,
1921 								   bs->bh);
1922 			if (error)
1923 				goto cleanup;
1924 			goto inserted;
1925 		}
1926 clone_block:
1927 		unlock_buffer(bs->bh);
1928 		ea_bdebug(bs->bh, "cloning");
1929 		s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
1930 		error = -ENOMEM;
1931 		if (s->base == NULL)
1932 			goto cleanup;
1933 		s->first = ENTRY(header(s->base)+1);
1934 		header(s->base)->h_refcount = cpu_to_le32(1);
1935 		s->here = ENTRY(s->base + offset);
1936 		s->end = s->base + bs->bh->b_size;
1937 
1938 		/*
1939 		 * If existing entry points to an xattr inode, we need
1940 		 * to prevent ext4_xattr_set_entry() from decrementing
1941 		 * ref count on it because the reference belongs to the
1942 		 * original block. In this case, make the entry look
1943 		 * like it has an empty value.
1944 		 */
1945 		if (!s->not_found && s->here->e_value_inum) {
1946 			ea_ino = le32_to_cpu(s->here->e_value_inum);
1947 			error = ext4_xattr_inode_iget(inode, ea_ino,
1948 				      le32_to_cpu(s->here->e_hash),
1949 				      &tmp_inode);
1950 			if (error)
1951 				goto cleanup;
1952 
1953 			if (!ext4_test_inode_state(tmp_inode,
1954 					EXT4_STATE_LUSTRE_EA_INODE)) {
1955 				/*
1956 				 * Defer quota free call for previous
1957 				 * inode until success is guaranteed.
1958 				 */
1959 				old_ea_inode_quota = le32_to_cpu(
1960 						s->here->e_value_size);
1961 			}
1962 			iput(tmp_inode);
1963 
1964 			s->here->e_value_inum = 0;
1965 			s->here->e_value_size = 0;
1966 		}
1967 	} else {
1968 		/* Allocate a buffer where we construct the new block. */
1969 		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1970 		/* assert(header == s->base) */
1971 		error = -ENOMEM;
1972 		if (s->base == NULL)
1973 			goto cleanup;
1974 		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1975 		header(s->base)->h_blocks = cpu_to_le32(1);
1976 		header(s->base)->h_refcount = cpu_to_le32(1);
1977 		s->first = ENTRY(header(s->base)+1);
1978 		s->here = ENTRY(header(s->base)+1);
1979 		s->end = s->base + sb->s_blocksize;
1980 	}
1981 
1982 	error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1983 	if (error == -EFSCORRUPTED)
1984 		goto bad_block;
1985 	if (error)
1986 		goto cleanup;
1987 
1988 	if (i->value && s->here->e_value_inum) {
1989 		/*
1990 		 * A ref count on ea_inode has been taken as part of the call to
1991 		 * ext4_xattr_set_entry() above. We would like to drop this
1992 		 * extra ref but we have to wait until the xattr block is
1993 		 * initialized and has its own ref count on the ea_inode.
1994 		 */
1995 		ea_ino = le32_to_cpu(s->here->e_value_inum);
1996 		error = ext4_xattr_inode_iget(inode, ea_ino,
1997 					      le32_to_cpu(s->here->e_hash),
1998 					      &ea_inode);
1999 		if (error) {
2000 			ea_inode = NULL;
2001 			goto cleanup;
2002 		}
2003 	}
2004 
2005 inserted:
2006 	if (!IS_LAST_ENTRY(s->first)) {
2007 		new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
2008 						     &ce);
2009 		if (new_bh) {
2010 			/* We found an identical block in the cache. */
2011 			if (new_bh == bs->bh)
2012 				ea_bdebug(new_bh, "keeping");
2013 			else {
2014 				u32 ref;
2015 
2016 #ifdef EXT4_XATTR_DEBUG
2017 				WARN_ON_ONCE(dquot_initialize_needed(inode));
2018 #endif
2019 				/* The old block is released after updating
2020 				   the inode. */
2021 				error = dquot_alloc_block(inode,
2022 						EXT4_C2B(EXT4_SB(sb), 1));
2023 				if (error)
2024 					goto cleanup;
2025 				BUFFER_TRACE(new_bh, "get_write_access");
2026 				error = ext4_journal_get_write_access(handle,
2027 								      new_bh);
2028 				if (error)
2029 					goto cleanup_dquot;
2030 				lock_buffer(new_bh);
2031 				/*
2032 				 * We have to be careful about races with
2033 				 * adding references to xattr block. Once we
2034 				 * hold buffer lock xattr block's state is
2035 				 * stable so we can check the additional
2036 				 * reference fits.
2037 				 */
2038 				ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2039 				if (ref > EXT4_XATTR_REFCOUNT_MAX) {
2040 					/*
2041 					 * Undo everything and check mbcache
2042 					 * again.
2043 					 */
2044 					unlock_buffer(new_bh);
2045 					dquot_free_block(inode,
2046 							 EXT4_C2B(EXT4_SB(sb),
2047 								  1));
2048 					brelse(new_bh);
2049 					mb_cache_entry_put(ea_block_cache, ce);
2050 					ce = NULL;
2051 					new_bh = NULL;
2052 					goto inserted;
2053 				}
2054 				BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2055 				if (ref == EXT4_XATTR_REFCOUNT_MAX)
2056 					clear_bit(MBE_REUSABLE_B, &ce->e_flags);
2057 				ea_bdebug(new_bh, "reusing; refcount now=%d",
2058 					  ref);
2059 				ext4_xattr_block_csum_set(inode, new_bh);
2060 				unlock_buffer(new_bh);
2061 				error = ext4_handle_dirty_metadata(handle,
2062 								   inode,
2063 								   new_bh);
2064 				if (error)
2065 					goto cleanup_dquot;
2066 			}
2067 			mb_cache_entry_touch(ea_block_cache, ce);
2068 			mb_cache_entry_put(ea_block_cache, ce);
2069 			ce = NULL;
2070 		} else if (bs->bh && s->base == bs->bh->b_data) {
2071 			/* We were modifying this block in-place. */
2072 			ea_bdebug(bs->bh, "keeping this block");
2073 			ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2074 			new_bh = bs->bh;
2075 			get_bh(new_bh);
2076 		} else {
2077 			/* We need to allocate a new block */
2078 			ext4_fsblk_t goal, block;
2079 
2080 #ifdef EXT4_XATTR_DEBUG
2081 			WARN_ON_ONCE(dquot_initialize_needed(inode));
2082 #endif
2083 			goal = ext4_group_first_block_no(sb,
2084 						EXT4_I(inode)->i_block_group);
2085 			block = ext4_new_meta_blocks(handle, inode, goal, 0,
2086 						     NULL, &error);
2087 			if (error)
2088 				goto cleanup;
2089 
2090 			ea_idebug(inode, "creating block %llu",
2091 				  (unsigned long long)block);
2092 
2093 			new_bh = sb_getblk(sb, block);
2094 			if (unlikely(!new_bh)) {
2095 				error = -ENOMEM;
2096 getblk_failed:
2097 				ext4_free_blocks(handle, inode, NULL, block, 1,
2098 						 EXT4_FREE_BLOCKS_METADATA);
2099 				goto cleanup;
2100 			}
2101 			error = ext4_xattr_inode_inc_ref_all(handle, inode,
2102 						      ENTRY(header(s->base)+1));
2103 			if (error)
2104 				goto getblk_failed;
2105 			if (ea_inode) {
2106 				/* Drop the extra ref on ea_inode. */
2107 				error = ext4_xattr_inode_dec_ref(handle,
2108 								 ea_inode);
2109 				if (error)
2110 					ext4_warning_inode(ea_inode,
2111 							   "dec ref error=%d",
2112 							   error);
2113 				iput(ea_inode);
2114 				ea_inode = NULL;
2115 			}
2116 
2117 			lock_buffer(new_bh);
2118 			error = ext4_journal_get_create_access(handle, new_bh);
2119 			if (error) {
2120 				unlock_buffer(new_bh);
2121 				error = -EIO;
2122 				goto getblk_failed;
2123 			}
2124 			memcpy(new_bh->b_data, s->base, new_bh->b_size);
2125 			ext4_xattr_block_csum_set(inode, new_bh);
2126 			set_buffer_uptodate(new_bh);
2127 			unlock_buffer(new_bh);
2128 			ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2129 			error = ext4_handle_dirty_metadata(handle, inode,
2130 							   new_bh);
2131 			if (error)
2132 				goto cleanup;
2133 		}
2134 	}
2135 
2136 	if (old_ea_inode_quota)
2137 		ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2138 
2139 	/* Update the inode. */
2140 	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2141 
2142 	/* Drop the previous xattr block. */
2143 	if (bs->bh && bs->bh != new_bh) {
2144 		struct ext4_xattr_inode_array *ea_inode_array = NULL;
2145 
2146 		ext4_xattr_release_block(handle, inode, bs->bh,
2147 					 &ea_inode_array,
2148 					 0 /* extra_credits */);
2149 		ext4_xattr_inode_array_free(ea_inode_array);
2150 	}
2151 	error = 0;
2152 
2153 cleanup:
2154 	if (ea_inode) {
2155 		int error2;
2156 
2157 		error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2158 		if (error2)
2159 			ext4_warning_inode(ea_inode, "dec ref error=%d",
2160 					   error2);
2161 
2162 		/* If there was an error, revert the quota charge. */
2163 		if (error)
2164 			ext4_xattr_inode_free_quota(inode, ea_inode,
2165 						    i_size_read(ea_inode));
2166 		iput(ea_inode);
2167 	}
2168 	if (ce)
2169 		mb_cache_entry_put(ea_block_cache, ce);
2170 	brelse(new_bh);
2171 	if (!(bs->bh && s->base == bs->bh->b_data))
2172 		kfree(s->base);
2173 
2174 	return error;
2175 
2176 cleanup_dquot:
2177 	dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2178 	goto cleanup;
2179 
2180 bad_block:
2181 	EXT4_ERROR_INODE(inode, "bad block %llu",
2182 			 EXT4_I(inode)->i_file_acl);
2183 	goto cleanup;
2184 
2185 #undef header
2186 }
2187 
ext4_xattr_ibody_find(struct inode * inode,struct ext4_xattr_info * i,struct ext4_xattr_ibody_find * is)2188 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2189 			  struct ext4_xattr_ibody_find *is)
2190 {
2191 	struct ext4_xattr_ibody_header *header;
2192 	struct ext4_inode *raw_inode;
2193 	int error;
2194 
2195 	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2196 		return 0;
2197 
2198 	raw_inode = ext4_raw_inode(&is->iloc);
2199 	header = IHDR(inode, raw_inode);
2200 	is->s.base = is->s.first = IFIRST(header);
2201 	is->s.here = is->s.first;
2202 	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2203 	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2204 		error = xattr_check_inode(inode, header, is->s.end);
2205 		if (error)
2206 			return error;
2207 		/* Find the named attribute. */
2208 		error = xattr_find_entry(inode, &is->s.here, is->s.end,
2209 					 i->name_index, i->name, 0);
2210 		if (error && error != -ENODATA)
2211 			return error;
2212 		is->s.not_found = error;
2213 	}
2214 	return 0;
2215 }
2216 
ext4_xattr_ibody_set(handle_t * handle,struct inode * inode,struct ext4_xattr_info * i,struct ext4_xattr_ibody_find * is)2217 int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2218 				struct ext4_xattr_info *i,
2219 				struct ext4_xattr_ibody_find *is)
2220 {
2221 	struct ext4_xattr_ibody_header *header;
2222 	struct ext4_xattr_search *s = &is->s;
2223 	int error;
2224 
2225 	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2226 		return -ENOSPC;
2227 
2228 	error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2229 	if (error)
2230 		return error;
2231 	header = IHDR(inode, ext4_raw_inode(&is->iloc));
2232 	if (!IS_LAST_ENTRY(s->first)) {
2233 		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2234 		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2235 	} else {
2236 		header->h_magic = cpu_to_le32(0);
2237 		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2238 	}
2239 	return 0;
2240 }
2241 
ext4_xattr_value_same(struct ext4_xattr_search * s,struct ext4_xattr_info * i)2242 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2243 				 struct ext4_xattr_info *i)
2244 {
2245 	void *value;
2246 
2247 	/* When e_value_inum is set the value is stored externally. */
2248 	if (s->here->e_value_inum)
2249 		return 0;
2250 	if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2251 		return 0;
2252 	value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2253 	return !memcmp(value, i->value, i->value_len);
2254 }
2255 
ext4_xattr_get_block(struct inode * inode)2256 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2257 {
2258 	struct buffer_head *bh;
2259 	int error;
2260 
2261 	if (!EXT4_I(inode)->i_file_acl)
2262 		return NULL;
2263 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2264 	if (IS_ERR(bh))
2265 		return bh;
2266 	error = ext4_xattr_check_block(inode, bh);
2267 	if (error) {
2268 		brelse(bh);
2269 		return ERR_PTR(error);
2270 	}
2271 	return bh;
2272 }
2273 
2274 /*
2275  * ext4_xattr_set_handle()
2276  *
2277  * Create, replace or remove an extended attribute for this inode.  Value
2278  * is NULL to remove an existing extended attribute, and non-NULL to
2279  * either replace an existing extended attribute, or create a new extended
2280  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2281  * specify that an extended attribute must exist and must not exist
2282  * previous to the call, respectively.
2283  *
2284  * Returns 0, or a negative error number on failure.
2285  */
2286 int
ext4_xattr_set_handle(handle_t * handle,struct inode * inode,int name_index,const char * name,const void * value,size_t value_len,int flags)2287 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2288 		      const char *name, const void *value, size_t value_len,
2289 		      int flags)
2290 {
2291 	struct ext4_xattr_info i = {
2292 		.name_index = name_index,
2293 		.name = name,
2294 		.value = value,
2295 		.value_len = value_len,
2296 		.in_inode = 0,
2297 	};
2298 	struct ext4_xattr_ibody_find is = {
2299 		.s = { .not_found = -ENODATA, },
2300 	};
2301 	struct ext4_xattr_block_find bs = {
2302 		.s = { .not_found = -ENODATA, },
2303 	};
2304 	int no_expand;
2305 	int error;
2306 
2307 	if (!name)
2308 		return -EINVAL;
2309 	if (strlen(name) > 255)
2310 		return -ERANGE;
2311 
2312 	ext4_write_lock_xattr(inode, &no_expand);
2313 
2314 	/* Check journal credits under write lock. */
2315 	if (ext4_handle_valid(handle)) {
2316 		struct buffer_head *bh;
2317 		int credits;
2318 
2319 		bh = ext4_xattr_get_block(inode);
2320 		if (IS_ERR(bh)) {
2321 			error = PTR_ERR(bh);
2322 			goto cleanup;
2323 		}
2324 
2325 		credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2326 						   value_len,
2327 						   flags & XATTR_CREATE);
2328 		brelse(bh);
2329 
2330 		if (jbd2_handle_buffer_credits(handle) < credits) {
2331 			error = -ENOSPC;
2332 			goto cleanup;
2333 		}
2334 		WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2335 	}
2336 
2337 	error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2338 	if (error)
2339 		goto cleanup;
2340 
2341 	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2342 		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2343 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2344 		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2345 	}
2346 
2347 	error = ext4_xattr_ibody_find(inode, &i, &is);
2348 	if (error)
2349 		goto cleanup;
2350 	if (is.s.not_found)
2351 		error = ext4_xattr_block_find(inode, &i, &bs);
2352 	if (error)
2353 		goto cleanup;
2354 	if (is.s.not_found && bs.s.not_found) {
2355 		error = -ENODATA;
2356 		if (flags & XATTR_REPLACE)
2357 			goto cleanup;
2358 		error = 0;
2359 		if (!value)
2360 			goto cleanup;
2361 	} else {
2362 		error = -EEXIST;
2363 		if (flags & XATTR_CREATE)
2364 			goto cleanup;
2365 	}
2366 
2367 	if (!value) {
2368 		if (!is.s.not_found)
2369 			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2370 		else if (!bs.s.not_found)
2371 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2372 	} else {
2373 		error = 0;
2374 		/* Xattr value did not change? Save us some work and bail out */
2375 		if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2376 			goto cleanup;
2377 		if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2378 			goto cleanup;
2379 
2380 		if (ext4_has_feature_ea_inode(inode->i_sb) &&
2381 		    (EXT4_XATTR_SIZE(i.value_len) >
2382 			EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2383 			i.in_inode = 1;
2384 retry_inode:
2385 		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2386 		if (!error && !bs.s.not_found) {
2387 			i.value = NULL;
2388 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2389 		} else if (error == -ENOSPC) {
2390 			if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2391 				brelse(bs.bh);
2392 				bs.bh = NULL;
2393 				error = ext4_xattr_block_find(inode, &i, &bs);
2394 				if (error)
2395 					goto cleanup;
2396 			}
2397 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2398 			if (!error && !is.s.not_found) {
2399 				i.value = NULL;
2400 				error = ext4_xattr_ibody_set(handle, inode, &i,
2401 							     &is);
2402 			} else if (error == -ENOSPC) {
2403 				/*
2404 				 * Xattr does not fit in the block, store at
2405 				 * external inode if possible.
2406 				 */
2407 				if (ext4_has_feature_ea_inode(inode->i_sb) &&
2408 				    i.value_len && !i.in_inode) {
2409 					i.in_inode = 1;
2410 					goto retry_inode;
2411 				}
2412 			}
2413 		}
2414 	}
2415 	if (!error) {
2416 		ext4_xattr_update_super_block(handle, inode->i_sb);
2417 		inode->i_ctime = current_time(inode);
2418 		if (!value)
2419 			no_expand = 0;
2420 		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2421 		/*
2422 		 * The bh is consumed by ext4_mark_iloc_dirty, even with
2423 		 * error != 0.
2424 		 */
2425 		is.iloc.bh = NULL;
2426 		if (IS_SYNC(inode))
2427 			ext4_handle_sync(handle);
2428 	}
2429 	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2430 
2431 cleanup:
2432 	brelse(is.iloc.bh);
2433 	brelse(bs.bh);
2434 	ext4_write_unlock_xattr(inode, &no_expand);
2435 	return error;
2436 }
2437 
ext4_xattr_set_credits(struct inode * inode,size_t value_len,bool is_create,int * credits)2438 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2439 			   bool is_create, int *credits)
2440 {
2441 	struct buffer_head *bh;
2442 	int err;
2443 
2444 	*credits = 0;
2445 
2446 	if (!EXT4_SB(inode->i_sb)->s_journal)
2447 		return 0;
2448 
2449 	down_read(&EXT4_I(inode)->xattr_sem);
2450 
2451 	bh = ext4_xattr_get_block(inode);
2452 	if (IS_ERR(bh)) {
2453 		err = PTR_ERR(bh);
2454 	} else {
2455 		*credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2456 						    value_len, is_create);
2457 		brelse(bh);
2458 		err = 0;
2459 	}
2460 
2461 	up_read(&EXT4_I(inode)->xattr_sem);
2462 	return err;
2463 }
2464 
2465 /*
2466  * ext4_xattr_set()
2467  *
2468  * Like ext4_xattr_set_handle, but start from an inode. This extended
2469  * attribute modification is a filesystem transaction by itself.
2470  *
2471  * Returns 0, or a negative error number on failure.
2472  */
2473 int
ext4_xattr_set(struct inode * inode,int name_index,const char * name,const void * value,size_t value_len,int flags)2474 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2475 	       const void *value, size_t value_len, int flags)
2476 {
2477 	handle_t *handle;
2478 	struct super_block *sb = inode->i_sb;
2479 	int error, retries = 0;
2480 	int credits;
2481 
2482 	error = dquot_initialize(inode);
2483 	if (error)
2484 		return error;
2485 
2486 retry:
2487 	error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2488 				       &credits);
2489 	if (error)
2490 		return error;
2491 
2492 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2493 	if (IS_ERR(handle)) {
2494 		error = PTR_ERR(handle);
2495 	} else {
2496 		int error2;
2497 
2498 		error = ext4_xattr_set_handle(handle, inode, name_index, name,
2499 					      value, value_len, flags);
2500 		error2 = ext4_journal_stop(handle);
2501 		if (error == -ENOSPC &&
2502 		    ext4_should_retry_alloc(sb, &retries))
2503 			goto retry;
2504 		if (error == 0)
2505 			error = error2;
2506 	}
2507 	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2508 
2509 	return error;
2510 }
2511 
2512 /*
2513  * Shift the EA entries in the inode to create space for the increased
2514  * i_extra_isize.
2515  */
ext4_xattr_shift_entries(struct ext4_xattr_entry * entry,int value_offs_shift,void * to,void * from,size_t n)2516 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2517 				     int value_offs_shift, void *to,
2518 				     void *from, size_t n)
2519 {
2520 	struct ext4_xattr_entry *last = entry;
2521 	int new_offs;
2522 
2523 	/* We always shift xattr headers further thus offsets get lower */
2524 	BUG_ON(value_offs_shift > 0);
2525 
2526 	/* Adjust the value offsets of the entries */
2527 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2528 		if (!last->e_value_inum && last->e_value_size) {
2529 			new_offs = le16_to_cpu(last->e_value_offs) +
2530 							value_offs_shift;
2531 			last->e_value_offs = cpu_to_le16(new_offs);
2532 		}
2533 	}
2534 	/* Shift the entries by n bytes */
2535 	memmove(to, from, n);
2536 }
2537 
2538 /*
2539  * Move xattr pointed to by 'entry' from inode into external xattr block
2540  */
ext4_xattr_move_to_block(handle_t * handle,struct inode * inode,struct ext4_inode * raw_inode,struct ext4_xattr_entry * entry)2541 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2542 				    struct ext4_inode *raw_inode,
2543 				    struct ext4_xattr_entry *entry)
2544 {
2545 	struct ext4_xattr_ibody_find *is = NULL;
2546 	struct ext4_xattr_block_find *bs = NULL;
2547 	char *buffer = NULL, *b_entry_name = NULL;
2548 	size_t value_size = le32_to_cpu(entry->e_value_size);
2549 	struct ext4_xattr_info i = {
2550 		.value = NULL,
2551 		.value_len = 0,
2552 		.name_index = entry->e_name_index,
2553 		.in_inode = !!entry->e_value_inum,
2554 	};
2555 	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2556 	int needs_kvfree = 0;
2557 	int error;
2558 
2559 	is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2560 	bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2561 	b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2562 	if (!is || !bs || !b_entry_name) {
2563 		error = -ENOMEM;
2564 		goto out;
2565 	}
2566 
2567 	is->s.not_found = -ENODATA;
2568 	bs->s.not_found = -ENODATA;
2569 	is->iloc.bh = NULL;
2570 	bs->bh = NULL;
2571 
2572 	/* Save the entry name and the entry value */
2573 	if (entry->e_value_inum) {
2574 		buffer = kvmalloc(value_size, GFP_NOFS);
2575 		if (!buffer) {
2576 			error = -ENOMEM;
2577 			goto out;
2578 		}
2579 		needs_kvfree = 1;
2580 		error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2581 		if (error)
2582 			goto out;
2583 	} else {
2584 		size_t value_offs = le16_to_cpu(entry->e_value_offs);
2585 		buffer = (void *)IFIRST(header) + value_offs;
2586 	}
2587 
2588 	memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2589 	b_entry_name[entry->e_name_len] = '\0';
2590 	i.name = b_entry_name;
2591 
2592 	error = ext4_get_inode_loc(inode, &is->iloc);
2593 	if (error)
2594 		goto out;
2595 
2596 	error = ext4_xattr_ibody_find(inode, &i, is);
2597 	if (error)
2598 		goto out;
2599 
2600 	i.value = buffer;
2601 	i.value_len = value_size;
2602 	error = ext4_xattr_block_find(inode, &i, bs);
2603 	if (error)
2604 		goto out;
2605 
2606 	/* Move ea entry from the inode into the block */
2607 	error = ext4_xattr_block_set(handle, inode, &i, bs);
2608 	if (error)
2609 		goto out;
2610 
2611 	/* Remove the chosen entry from the inode */
2612 	i.value = NULL;
2613 	i.value_len = 0;
2614 	error = ext4_xattr_ibody_set(handle, inode, &i, is);
2615 
2616 out:
2617 	kfree(b_entry_name);
2618 	if (needs_kvfree && buffer)
2619 		kvfree(buffer);
2620 	if (is)
2621 		brelse(is->iloc.bh);
2622 	if (bs)
2623 		brelse(bs->bh);
2624 	kfree(is);
2625 	kfree(bs);
2626 
2627 	return error;
2628 }
2629 
ext4_xattr_make_inode_space(handle_t * handle,struct inode * inode,struct ext4_inode * raw_inode,int isize_diff,size_t ifree,size_t bfree,int * total_ino)2630 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2631 				       struct ext4_inode *raw_inode,
2632 				       int isize_diff, size_t ifree,
2633 				       size_t bfree, int *total_ino)
2634 {
2635 	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2636 	struct ext4_xattr_entry *small_entry;
2637 	struct ext4_xattr_entry *entry;
2638 	struct ext4_xattr_entry *last;
2639 	unsigned int entry_size;	/* EA entry size */
2640 	unsigned int total_size;	/* EA entry size + value size */
2641 	unsigned int min_total_size;
2642 	int error;
2643 
2644 	while (isize_diff > ifree) {
2645 		entry = NULL;
2646 		small_entry = NULL;
2647 		min_total_size = ~0U;
2648 		last = IFIRST(header);
2649 		/* Find the entry best suited to be pushed into EA block */
2650 		for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2651 			/* never move system.data out of the inode */
2652 			if ((last->e_name_len == 4) &&
2653 			    (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2654 			    !memcmp(last->e_name, "data", 4))
2655 				continue;
2656 			total_size = EXT4_XATTR_LEN(last->e_name_len);
2657 			if (!last->e_value_inum)
2658 				total_size += EXT4_XATTR_SIZE(
2659 					       le32_to_cpu(last->e_value_size));
2660 			if (total_size <= bfree &&
2661 			    total_size < min_total_size) {
2662 				if (total_size + ifree < isize_diff) {
2663 					small_entry = last;
2664 				} else {
2665 					entry = last;
2666 					min_total_size = total_size;
2667 				}
2668 			}
2669 		}
2670 
2671 		if (entry == NULL) {
2672 			if (small_entry == NULL)
2673 				return -ENOSPC;
2674 			entry = small_entry;
2675 		}
2676 
2677 		entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2678 		total_size = entry_size;
2679 		if (!entry->e_value_inum)
2680 			total_size += EXT4_XATTR_SIZE(
2681 					      le32_to_cpu(entry->e_value_size));
2682 		error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2683 						 entry);
2684 		if (error)
2685 			return error;
2686 
2687 		*total_ino -= entry_size;
2688 		ifree += total_size;
2689 		bfree -= total_size;
2690 	}
2691 
2692 	return 0;
2693 }
2694 
2695 /*
2696  * Expand an inode by new_extra_isize bytes when EAs are present.
2697  * Returns 0 on success or negative error number on failure.
2698  */
ext4_expand_extra_isize_ea(struct inode * inode,int new_extra_isize,struct ext4_inode * raw_inode,handle_t * handle)2699 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2700 			       struct ext4_inode *raw_inode, handle_t *handle)
2701 {
2702 	struct ext4_xattr_ibody_header *header;
2703 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2704 	static unsigned int mnt_count;
2705 	size_t min_offs;
2706 	size_t ifree, bfree;
2707 	int total_ino;
2708 	void *base, *end;
2709 	int error = 0, tried_min_extra_isize = 0;
2710 	int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2711 	int isize_diff;	/* How much do we need to grow i_extra_isize */
2712 
2713 retry:
2714 	isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2715 	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2716 		return 0;
2717 
2718 	header = IHDR(inode, raw_inode);
2719 
2720 	/*
2721 	 * Check if enough free space is available in the inode to shift the
2722 	 * entries ahead by new_extra_isize.
2723 	 */
2724 
2725 	base = IFIRST(header);
2726 	end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2727 	min_offs = end - base;
2728 	total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2729 
2730 	error = xattr_check_inode(inode, header, end);
2731 	if (error)
2732 		goto cleanup;
2733 
2734 	ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2735 	if (ifree >= isize_diff)
2736 		goto shift;
2737 
2738 	/*
2739 	 * Enough free space isn't available in the inode, check if
2740 	 * EA block can hold new_extra_isize bytes.
2741 	 */
2742 	if (EXT4_I(inode)->i_file_acl) {
2743 		struct buffer_head *bh;
2744 
2745 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2746 		if (IS_ERR(bh)) {
2747 			error = PTR_ERR(bh);
2748 			goto cleanup;
2749 		}
2750 		error = ext4_xattr_check_block(inode, bh);
2751 		if (error) {
2752 			brelse(bh);
2753 			goto cleanup;
2754 		}
2755 		base = BHDR(bh);
2756 		end = bh->b_data + bh->b_size;
2757 		min_offs = end - base;
2758 		bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2759 					      NULL);
2760 		brelse(bh);
2761 		if (bfree + ifree < isize_diff) {
2762 			if (!tried_min_extra_isize && s_min_extra_isize) {
2763 				tried_min_extra_isize++;
2764 				new_extra_isize = s_min_extra_isize;
2765 				goto retry;
2766 			}
2767 			error = -ENOSPC;
2768 			goto cleanup;
2769 		}
2770 	} else {
2771 		bfree = inode->i_sb->s_blocksize;
2772 	}
2773 
2774 	error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2775 					    isize_diff, ifree, bfree,
2776 					    &total_ino);
2777 	if (error) {
2778 		if (error == -ENOSPC && !tried_min_extra_isize &&
2779 		    s_min_extra_isize) {
2780 			tried_min_extra_isize++;
2781 			new_extra_isize = s_min_extra_isize;
2782 			goto retry;
2783 		}
2784 		goto cleanup;
2785 	}
2786 shift:
2787 	/* Adjust the offsets and shift the remaining entries ahead */
2788 	ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2789 			- new_extra_isize, (void *)raw_inode +
2790 			EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2791 			(void *)header, total_ino);
2792 	EXT4_I(inode)->i_extra_isize = new_extra_isize;
2793 
2794 	if (ext4_has_inline_data(inode))
2795 		error = ext4_find_inline_data_nolock(inode);
2796 
2797 cleanup:
2798 	if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2799 		ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2800 			     inode->i_ino);
2801 		mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2802 	}
2803 	return error;
2804 }
2805 
2806 #define EIA_INCR 16 /* must be 2^n */
2807 #define EIA_MASK (EIA_INCR - 1)
2808 
2809 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2810  * If @ea_inode_array is new or full it will be grown and the old
2811  * contents copied over.
2812  */
2813 static int
ext4_expand_inode_array(struct ext4_xattr_inode_array ** ea_inode_array,struct inode * inode)2814 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2815 			struct inode *inode)
2816 {
2817 	if (*ea_inode_array == NULL) {
2818 		/*
2819 		 * Start with 15 inodes, so it fits into a power-of-two size.
2820 		 * If *ea_inode_array is NULL, this is essentially offsetof()
2821 		 */
2822 		(*ea_inode_array) =
2823 			kmalloc(offsetof(struct ext4_xattr_inode_array,
2824 					 inodes[EIA_MASK]),
2825 				GFP_NOFS);
2826 		if (*ea_inode_array == NULL)
2827 			return -ENOMEM;
2828 		(*ea_inode_array)->count = 0;
2829 	} else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2830 		/* expand the array once all 15 + n * 16 slots are full */
2831 		struct ext4_xattr_inode_array *new_array = NULL;
2832 		int count = (*ea_inode_array)->count;
2833 
2834 		/* if new_array is NULL, this is essentially offsetof() */
2835 		new_array = kmalloc(
2836 				offsetof(struct ext4_xattr_inode_array,
2837 					 inodes[count + EIA_INCR]),
2838 				GFP_NOFS);
2839 		if (new_array == NULL)
2840 			return -ENOMEM;
2841 		memcpy(new_array, *ea_inode_array,
2842 		       offsetof(struct ext4_xattr_inode_array, inodes[count]));
2843 		kfree(*ea_inode_array);
2844 		*ea_inode_array = new_array;
2845 	}
2846 	(*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2847 	return 0;
2848 }
2849 
2850 /*
2851  * ext4_xattr_delete_inode()
2852  *
2853  * Free extended attribute resources associated with this inode. Traverse
2854  * all entries and decrement reference on any xattr inodes associated with this
2855  * inode. This is called immediately before an inode is freed. We have exclusive
2856  * access to the inode. If an orphan inode is deleted it will also release its
2857  * references on xattr block and xattr inodes.
2858  */
ext4_xattr_delete_inode(handle_t * handle,struct inode * inode,struct ext4_xattr_inode_array ** ea_inode_array,int extra_credits)2859 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2860 			    struct ext4_xattr_inode_array **ea_inode_array,
2861 			    int extra_credits)
2862 {
2863 	struct buffer_head *bh = NULL;
2864 	struct ext4_xattr_ibody_header *header;
2865 	struct ext4_iloc iloc = { .bh = NULL };
2866 	struct ext4_xattr_entry *entry;
2867 	struct inode *ea_inode;
2868 	int error;
2869 
2870 	error = ext4_journal_ensure_credits(handle, extra_credits,
2871 			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2872 	if (error < 0) {
2873 		EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2874 		goto cleanup;
2875 	}
2876 
2877 	if (ext4_has_feature_ea_inode(inode->i_sb) &&
2878 	    ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2879 
2880 		error = ext4_get_inode_loc(inode, &iloc);
2881 		if (error) {
2882 			EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2883 			goto cleanup;
2884 		}
2885 
2886 		error = ext4_journal_get_write_access(handle, iloc.bh);
2887 		if (error) {
2888 			EXT4_ERROR_INODE(inode, "write access (error %d)",
2889 					 error);
2890 			goto cleanup;
2891 		}
2892 
2893 		header = IHDR(inode, ext4_raw_inode(&iloc));
2894 		if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2895 			ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2896 						     IFIRST(header),
2897 						     false /* block_csum */,
2898 						     ea_inode_array,
2899 						     extra_credits,
2900 						     false /* skip_quota */);
2901 	}
2902 
2903 	if (EXT4_I(inode)->i_file_acl) {
2904 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2905 		if (IS_ERR(bh)) {
2906 			error = PTR_ERR(bh);
2907 			if (error == -EIO) {
2908 				EXT4_ERROR_INODE_ERR(inode, EIO,
2909 						     "block %llu read error",
2910 						     EXT4_I(inode)->i_file_acl);
2911 			}
2912 			bh = NULL;
2913 			goto cleanup;
2914 		}
2915 		error = ext4_xattr_check_block(inode, bh);
2916 		if (error)
2917 			goto cleanup;
2918 
2919 		if (ext4_has_feature_ea_inode(inode->i_sb)) {
2920 			for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2921 			     entry = EXT4_XATTR_NEXT(entry)) {
2922 				if (!entry->e_value_inum)
2923 					continue;
2924 				error = ext4_xattr_inode_iget(inode,
2925 					      le32_to_cpu(entry->e_value_inum),
2926 					      le32_to_cpu(entry->e_hash),
2927 					      &ea_inode);
2928 				if (error)
2929 					continue;
2930 				ext4_xattr_inode_free_quota(inode, ea_inode,
2931 					      le32_to_cpu(entry->e_value_size));
2932 				iput(ea_inode);
2933 			}
2934 
2935 		}
2936 
2937 		ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2938 					 extra_credits);
2939 		/*
2940 		 * Update i_file_acl value in the same transaction that releases
2941 		 * block.
2942 		 */
2943 		EXT4_I(inode)->i_file_acl = 0;
2944 		error = ext4_mark_inode_dirty(handle, inode);
2945 		if (error) {
2946 			EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2947 					 error);
2948 			goto cleanup;
2949 		}
2950 		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2951 	}
2952 	error = 0;
2953 cleanup:
2954 	brelse(iloc.bh);
2955 	brelse(bh);
2956 	return error;
2957 }
2958 
ext4_xattr_inode_array_free(struct ext4_xattr_inode_array * ea_inode_array)2959 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2960 {
2961 	int idx;
2962 
2963 	if (ea_inode_array == NULL)
2964 		return;
2965 
2966 	for (idx = 0; idx < ea_inode_array->count; ++idx)
2967 		iput(ea_inode_array->inodes[idx]);
2968 	kfree(ea_inode_array);
2969 }
2970 
2971 /*
2972  * ext4_xattr_block_cache_insert()
2973  *
2974  * Create a new entry in the extended attribute block cache, and insert
2975  * it unless such an entry is already in the cache.
2976  *
2977  * Returns 0, or a negative error number on failure.
2978  */
2979 static void
ext4_xattr_block_cache_insert(struct mb_cache * ea_block_cache,struct buffer_head * bh)2980 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2981 			      struct buffer_head *bh)
2982 {
2983 	struct ext4_xattr_header *header = BHDR(bh);
2984 	__u32 hash = le32_to_cpu(header->h_hash);
2985 	int reusable = le32_to_cpu(header->h_refcount) <
2986 		       EXT4_XATTR_REFCOUNT_MAX;
2987 	int error;
2988 
2989 	if (!ea_block_cache)
2990 		return;
2991 	error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2992 				      bh->b_blocknr, reusable);
2993 	if (error) {
2994 		if (error == -EBUSY)
2995 			ea_bdebug(bh, "already in cache");
2996 	} else
2997 		ea_bdebug(bh, "inserting [%x]", (int)hash);
2998 }
2999 
3000 /*
3001  * ext4_xattr_cmp()
3002  *
3003  * Compare two extended attribute blocks for equality.
3004  *
3005  * Returns 0 if the blocks are equal, 1 if they differ, and
3006  * a negative error number on errors.
3007  */
3008 static int
ext4_xattr_cmp(struct ext4_xattr_header * header1,struct ext4_xattr_header * header2)3009 ext4_xattr_cmp(struct ext4_xattr_header *header1,
3010 	       struct ext4_xattr_header *header2)
3011 {
3012 	struct ext4_xattr_entry *entry1, *entry2;
3013 
3014 	entry1 = ENTRY(header1+1);
3015 	entry2 = ENTRY(header2+1);
3016 	while (!IS_LAST_ENTRY(entry1)) {
3017 		if (IS_LAST_ENTRY(entry2))
3018 			return 1;
3019 		if (entry1->e_hash != entry2->e_hash ||
3020 		    entry1->e_name_index != entry2->e_name_index ||
3021 		    entry1->e_name_len != entry2->e_name_len ||
3022 		    entry1->e_value_size != entry2->e_value_size ||
3023 		    entry1->e_value_inum != entry2->e_value_inum ||
3024 		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3025 			return 1;
3026 		if (!entry1->e_value_inum &&
3027 		    memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3028 			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3029 			   le32_to_cpu(entry1->e_value_size)))
3030 			return 1;
3031 
3032 		entry1 = EXT4_XATTR_NEXT(entry1);
3033 		entry2 = EXT4_XATTR_NEXT(entry2);
3034 	}
3035 	if (!IS_LAST_ENTRY(entry2))
3036 		return 1;
3037 	return 0;
3038 }
3039 
3040 /*
3041  * ext4_xattr_block_cache_find()
3042  *
3043  * Find an identical extended attribute block.
3044  *
3045  * Returns a pointer to the block found, or NULL if such a block was
3046  * not found or an error occurred.
3047  */
3048 static struct buffer_head *
ext4_xattr_block_cache_find(struct inode * inode,struct ext4_xattr_header * header,struct mb_cache_entry ** pce)3049 ext4_xattr_block_cache_find(struct inode *inode,
3050 			    struct ext4_xattr_header *header,
3051 			    struct mb_cache_entry **pce)
3052 {
3053 	__u32 hash = le32_to_cpu(header->h_hash);
3054 	struct mb_cache_entry *ce;
3055 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3056 
3057 	if (!ea_block_cache)
3058 		return NULL;
3059 	if (!header->h_hash)
3060 		return NULL;  /* never share */
3061 	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3062 	ce = mb_cache_entry_find_first(ea_block_cache, hash);
3063 	while (ce) {
3064 		struct buffer_head *bh;
3065 
3066 		bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3067 		if (IS_ERR(bh)) {
3068 			if (PTR_ERR(bh) == -ENOMEM)
3069 				return NULL;
3070 			bh = NULL;
3071 			EXT4_ERROR_INODE(inode, "block %lu read error",
3072 					 (unsigned long)ce->e_value);
3073 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3074 			*pce = ce;
3075 			return bh;
3076 		}
3077 		brelse(bh);
3078 		ce = mb_cache_entry_find_next(ea_block_cache, ce);
3079 	}
3080 	return NULL;
3081 }
3082 
3083 #define NAME_HASH_SHIFT 5
3084 #define VALUE_HASH_SHIFT 16
3085 
3086 /*
3087  * ext4_xattr_hash_entry()
3088  *
3089  * Compute the hash of an extended attribute.
3090  */
ext4_xattr_hash_entry(char * name,size_t name_len,__le32 * value,size_t value_count)3091 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3092 				    size_t value_count)
3093 {
3094 	__u32 hash = 0;
3095 
3096 	while (name_len--) {
3097 		hash = (hash << NAME_HASH_SHIFT) ^
3098 		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3099 		       *name++;
3100 	}
3101 	while (value_count--) {
3102 		hash = (hash << VALUE_HASH_SHIFT) ^
3103 		       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3104 		       le32_to_cpu(*value++);
3105 	}
3106 	return cpu_to_le32(hash);
3107 }
3108 
3109 #undef NAME_HASH_SHIFT
3110 #undef VALUE_HASH_SHIFT
3111 
3112 #define BLOCK_HASH_SHIFT 16
3113 
3114 /*
3115  * ext4_xattr_rehash()
3116  *
3117  * Re-compute the extended attribute hash value after an entry has changed.
3118  */
ext4_xattr_rehash(struct ext4_xattr_header * header)3119 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3120 {
3121 	struct ext4_xattr_entry *here;
3122 	__u32 hash = 0;
3123 
3124 	here = ENTRY(header+1);
3125 	while (!IS_LAST_ENTRY(here)) {
3126 		if (!here->e_hash) {
3127 			/* Block is not shared if an entry's hash value == 0 */
3128 			hash = 0;
3129 			break;
3130 		}
3131 		hash = (hash << BLOCK_HASH_SHIFT) ^
3132 		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3133 		       le32_to_cpu(here->e_hash);
3134 		here = EXT4_XATTR_NEXT(here);
3135 	}
3136 	header->h_hash = cpu_to_le32(hash);
3137 }
3138 
3139 #undef BLOCK_HASH_SHIFT
3140 
3141 #define	HASH_BUCKET_BITS	10
3142 
3143 struct mb_cache *
ext4_xattr_create_cache(void)3144 ext4_xattr_create_cache(void)
3145 {
3146 	return mb_cache_create(HASH_BUCKET_BITS);
3147 }
3148 
ext4_xattr_destroy_cache(struct mb_cache * cache)3149 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3150 {
3151 	if (cache)
3152 		mb_cache_destroy(cache);
3153 }
3154 
3155