xref: /linux/fs/ext4/xattr.c (revision 5c2a430e85994f4873ea5ec42091baa1153bc731)
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 __le32 ext4_xattr_hash_entry_signed(char *name, size_t name_len, __le32 *value,
85 				    size_t value_count);
86 static void ext4_xattr_rehash(struct ext4_xattr_header *);
87 
88 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
89 	[EXT4_XATTR_INDEX_USER]		     = &ext4_xattr_user_handler,
90 #ifdef CONFIG_EXT4_FS_POSIX_ACL
91 	[EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &nop_posix_acl_access,
92 	[EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &nop_posix_acl_default,
93 #endif
94 	[EXT4_XATTR_INDEX_TRUSTED]	     = &ext4_xattr_trusted_handler,
95 #ifdef CONFIG_EXT4_FS_SECURITY
96 	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
97 #endif
98 	[EXT4_XATTR_INDEX_HURD]		     = &ext4_xattr_hurd_handler,
99 };
100 
101 const struct xattr_handler * const ext4_xattr_handlers[] = {
102 	&ext4_xattr_user_handler,
103 	&ext4_xattr_trusted_handler,
104 #ifdef CONFIG_EXT4_FS_SECURITY
105 	&ext4_xattr_security_handler,
106 #endif
107 	&ext4_xattr_hurd_handler,
108 	NULL
109 };
110 
111 #define EA_BLOCK_CACHE(inode)	(((struct ext4_sb_info *) \
112 				inode->i_sb->s_fs_info)->s_ea_block_cache)
113 
114 #define EA_INODE_CACHE(inode)	(((struct ext4_sb_info *) \
115 				inode->i_sb->s_fs_info)->s_ea_inode_cache)
116 
117 static int
118 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
119 			struct inode *inode);
120 
121 #ifdef CONFIG_LOCKDEP
ext4_xattr_inode_set_class(struct inode * ea_inode)122 void ext4_xattr_inode_set_class(struct inode *ea_inode)
123 {
124 	struct ext4_inode_info *ei = EXT4_I(ea_inode);
125 
126 	lockdep_set_subclass(&ea_inode->i_rwsem, 1);
127 	(void) ei;	/* shut up clang warning if !CONFIG_LOCKDEP */
128 	lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA);
129 }
130 #endif
131 
ext4_xattr_block_csum(struct inode * inode,sector_t block_nr,struct ext4_xattr_header * hdr)132 static __le32 ext4_xattr_block_csum(struct inode *inode,
133 				    sector_t block_nr,
134 				    struct ext4_xattr_header *hdr)
135 {
136 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
137 	__u32 csum;
138 	__le64 dsk_block_nr = cpu_to_le64(block_nr);
139 	__u32 dummy_csum = 0;
140 	int offset = offsetof(struct ext4_xattr_header, h_checksum);
141 
142 	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
143 			   sizeof(dsk_block_nr));
144 	csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
145 	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
146 	offset += sizeof(dummy_csum);
147 	csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
148 			   EXT4_BLOCK_SIZE(inode->i_sb) - offset);
149 
150 	return cpu_to_le32(csum);
151 }
152 
ext4_xattr_block_csum_verify(struct inode * inode,struct buffer_head * bh)153 static int ext4_xattr_block_csum_verify(struct inode *inode,
154 					struct buffer_head *bh)
155 {
156 	struct ext4_xattr_header *hdr = BHDR(bh);
157 	int ret = 1;
158 
159 	if (ext4_has_feature_metadata_csum(inode->i_sb)) {
160 		lock_buffer(bh);
161 		ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
162 							bh->b_blocknr, hdr));
163 		unlock_buffer(bh);
164 	}
165 	return ret;
166 }
167 
ext4_xattr_block_csum_set(struct inode * inode,struct buffer_head * bh)168 static void ext4_xattr_block_csum_set(struct inode *inode,
169 				      struct buffer_head *bh)
170 {
171 	if (ext4_has_feature_metadata_csum(inode->i_sb))
172 		BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
173 						bh->b_blocknr, BHDR(bh));
174 }
175 
ext4_xattr_prefix(int name_index,struct dentry * dentry)176 static inline const char *ext4_xattr_prefix(int name_index,
177 					    struct dentry *dentry)
178 {
179 	const struct xattr_handler *handler = NULL;
180 
181 	if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
182 		handler = ext4_xattr_handler_map[name_index];
183 
184 	if (!xattr_handler_can_list(handler, dentry))
185 		return NULL;
186 
187 	return xattr_prefix(handler);
188 }
189 
190 static int
check_xattrs(struct inode * inode,struct buffer_head * bh,struct ext4_xattr_entry * entry,void * end,void * value_start,const char * function,unsigned int line)191 check_xattrs(struct inode *inode, struct buffer_head *bh,
192 	     struct ext4_xattr_entry *entry, void *end, void *value_start,
193 	     const char *function, unsigned int line)
194 {
195 	struct ext4_xattr_entry *e = entry;
196 	int err = -EFSCORRUPTED;
197 	char *err_str;
198 
199 	if (bh) {
200 		if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
201 		    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
202 			err_str = "invalid header";
203 			goto errout;
204 		}
205 		if (buffer_verified(bh))
206 			return 0;
207 		if (!ext4_xattr_block_csum_verify(inode, bh)) {
208 			err = -EFSBADCRC;
209 			err_str = "invalid checksum";
210 			goto errout;
211 		}
212 	} else {
213 		struct ext4_xattr_ibody_header *header = value_start;
214 
215 		header -= 1;
216 		if (end - (void *)header < sizeof(*header) + sizeof(u32)) {
217 			err_str = "in-inode xattr block too small";
218 			goto errout;
219 		}
220 		if (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
221 			err_str = "bad magic number in in-inode xattr";
222 			goto errout;
223 		}
224 	}
225 
226 	/* Find the end of the names list */
227 	while (!IS_LAST_ENTRY(e)) {
228 		struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
229 		if ((void *)next >= end) {
230 			err_str = "e_name out of bounds";
231 			goto errout;
232 		}
233 		if (strnlen(e->e_name, e->e_name_len) != e->e_name_len) {
234 			err_str = "bad e_name length";
235 			goto errout;
236 		}
237 		e = next;
238 	}
239 
240 	/* Check the values */
241 	while (!IS_LAST_ENTRY(entry)) {
242 		u32 size = le32_to_cpu(entry->e_value_size);
243 		unsigned long ea_ino = le32_to_cpu(entry->e_value_inum);
244 
245 		if (!ext4_has_feature_ea_inode(inode->i_sb) && ea_ino) {
246 			err_str = "ea_inode specified without ea_inode feature enabled";
247 			goto errout;
248 		}
249 		if (ea_ino && ((ea_ino == EXT4_ROOT_INO) ||
250 			       !ext4_valid_inum(inode->i_sb, ea_ino))) {
251 			err_str = "invalid ea_ino";
252 			goto errout;
253 		}
254 		if (size > EXT4_XATTR_SIZE_MAX) {
255 			err_str = "e_value size too large";
256 			goto errout;
257 		}
258 
259 		if (size != 0 && entry->e_value_inum == 0) {
260 			u16 offs = le16_to_cpu(entry->e_value_offs);
261 			void *value;
262 
263 			/*
264 			 * The value cannot overlap the names, and the value
265 			 * with padding cannot extend beyond 'end'.  Check both
266 			 * the padded and unpadded sizes, since the size may
267 			 * overflow to 0 when adding padding.
268 			 */
269 			if (offs > end - value_start) {
270 				err_str = "e_value out of bounds";
271 				goto errout;
272 			}
273 			value = value_start + offs;
274 			if (value < (void *)e + sizeof(u32) ||
275 			    size > end - value ||
276 			    EXT4_XATTR_SIZE(size) > end - value) {
277 				err_str = "overlapping e_value ";
278 				goto errout;
279 			}
280 		}
281 		entry = EXT4_XATTR_NEXT(entry);
282 	}
283 	if (bh)
284 		set_buffer_verified(bh);
285 	return 0;
286 
287 errout:
288 	if (bh)
289 		__ext4_error_inode(inode, function, line, 0, -err,
290 				   "corrupted xattr block %llu: %s",
291 				   (unsigned long long) bh->b_blocknr,
292 				   err_str);
293 	else
294 		__ext4_error_inode(inode, function, line, 0, -err,
295 				   "corrupted in-inode xattr: %s", err_str);
296 	return err;
297 }
298 
299 static inline int
__ext4_xattr_check_block(struct inode * inode,struct buffer_head * bh,const char * function,unsigned int line)300 __ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
301 			 const char *function, unsigned int line)
302 {
303 	return check_xattrs(inode, bh, BFIRST(bh), bh->b_data + bh->b_size,
304 			    bh->b_data, function, line);
305 }
306 
307 #define ext4_xattr_check_block(inode, bh) \
308 	__ext4_xattr_check_block((inode), (bh),  __func__, __LINE__)
309 
310 
311 int
__xattr_check_inode(struct inode * inode,struct ext4_xattr_ibody_header * header,void * end,const char * function,unsigned int line)312 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
313 			 void *end, const char *function, unsigned int line)
314 {
315 	return check_xattrs(inode, NULL, IFIRST(header), end, IFIRST(header),
316 			    function, line);
317 }
318 
319 static int
xattr_find_entry(struct inode * inode,struct ext4_xattr_entry ** pentry,void * end,int name_index,const char * name,int sorted)320 xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
321 		 void *end, int name_index, const char *name, int sorted)
322 {
323 	struct ext4_xattr_entry *entry, *next;
324 	size_t name_len;
325 	int cmp = 1;
326 
327 	if (name == NULL)
328 		return -EINVAL;
329 	name_len = strlen(name);
330 	for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
331 		next = EXT4_XATTR_NEXT(entry);
332 		if ((void *) next >= end) {
333 			EXT4_ERROR_INODE(inode, "corrupted xattr entries");
334 			return -EFSCORRUPTED;
335 		}
336 		cmp = name_index - entry->e_name_index;
337 		if (!cmp)
338 			cmp = name_len - entry->e_name_len;
339 		if (!cmp)
340 			cmp = memcmp(name, entry->e_name, name_len);
341 		if (cmp <= 0 && (sorted || cmp == 0))
342 			break;
343 	}
344 	*pentry = entry;
345 	return cmp ? -ENODATA : 0;
346 }
347 
348 static u32
ext4_xattr_inode_hash(struct ext4_sb_info * sbi,const void * buffer,size_t size)349 ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
350 {
351 	return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
352 }
353 
ext4_xattr_inode_get_ref(struct inode * ea_inode)354 static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
355 {
356 	return ((u64) inode_get_ctime_sec(ea_inode) << 32) |
357 		(u32) inode_peek_iversion_raw(ea_inode);
358 }
359 
ext4_xattr_inode_set_ref(struct inode * ea_inode,u64 ref_count)360 static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
361 {
362 	inode_set_ctime(ea_inode, (u32)(ref_count >> 32), 0);
363 	inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
364 }
365 
ext4_xattr_inode_get_hash(struct inode * ea_inode)366 static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
367 {
368 	return (u32) inode_get_atime_sec(ea_inode);
369 }
370 
ext4_xattr_inode_set_hash(struct inode * ea_inode,u32 hash)371 static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
372 {
373 	inode_set_atime(ea_inode, hash, 0);
374 }
375 
376 /*
377  * Read the EA value from an inode.
378  */
ext4_xattr_inode_read(struct inode * ea_inode,void * buf,size_t size)379 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
380 {
381 	int blocksize = 1 << ea_inode->i_blkbits;
382 	int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
383 	int tail_size = (size % blocksize) ?: blocksize;
384 	struct buffer_head *bhs_inline[8];
385 	struct buffer_head **bhs = bhs_inline;
386 	int i, ret;
387 
388 	if (bh_count > ARRAY_SIZE(bhs_inline)) {
389 		bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
390 		if (!bhs)
391 			return -ENOMEM;
392 	}
393 
394 	ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
395 			       true /* wait */, bhs);
396 	if (ret)
397 		goto free_bhs;
398 
399 	for (i = 0; i < bh_count; i++) {
400 		/* There shouldn't be any holes in ea_inode. */
401 		if (!bhs[i]) {
402 			ret = -EFSCORRUPTED;
403 			goto put_bhs;
404 		}
405 		memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
406 		       i < bh_count - 1 ? blocksize : tail_size);
407 	}
408 	ret = 0;
409 put_bhs:
410 	for (i = 0; i < bh_count; i++)
411 		brelse(bhs[i]);
412 free_bhs:
413 	if (bhs != bhs_inline)
414 		kfree(bhs);
415 	return ret;
416 }
417 
418 #define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode_get_mtime_sec(inode)))
419 
ext4_xattr_inode_iget(struct inode * parent,unsigned long ea_ino,u32 ea_inode_hash,struct inode ** ea_inode)420 static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
421 				 u32 ea_inode_hash, struct inode **ea_inode)
422 {
423 	struct inode *inode;
424 	int err;
425 
426 	/*
427 	 * We have to check for this corruption early as otherwise
428 	 * iget_locked() could wait indefinitely for the state of our
429 	 * parent inode.
430 	 */
431 	if (parent->i_ino == ea_ino) {
432 		ext4_error(parent->i_sb,
433 			   "Parent and EA inode have the same ino %lu", ea_ino);
434 		return -EFSCORRUPTED;
435 	}
436 
437 	inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_EA_INODE);
438 	if (IS_ERR(inode)) {
439 		err = PTR_ERR(inode);
440 		ext4_error(parent->i_sb,
441 			   "error while reading EA inode %lu err=%d", ea_ino,
442 			   err);
443 		return err;
444 	}
445 	ext4_xattr_inode_set_class(inode);
446 
447 	/*
448 	 * Check whether this is an old Lustre-style xattr inode. Lustre
449 	 * implementation does not have hash validation, rather it has a
450 	 * backpointer from ea_inode to the parent inode.
451 	 */
452 	if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
453 	    EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
454 	    inode->i_generation == parent->i_generation) {
455 		ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
456 		ext4_xattr_inode_set_ref(inode, 1);
457 	} else {
458 		inode_lock_nested(inode, I_MUTEX_XATTR);
459 		inode->i_flags |= S_NOQUOTA;
460 		inode_unlock(inode);
461 	}
462 
463 	*ea_inode = inode;
464 	return 0;
465 }
466 
467 /* Remove entry from mbcache when EA inode is getting evicted */
ext4_evict_ea_inode(struct inode * inode)468 void ext4_evict_ea_inode(struct inode *inode)
469 {
470 	struct mb_cache_entry *oe;
471 
472 	if (!EA_INODE_CACHE(inode))
473 		return;
474 	/* Wait for entry to get unused so that we can remove it */
475 	while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode),
476 			ext4_xattr_inode_get_hash(inode), inode->i_ino))) {
477 		mb_cache_entry_wait_unused(oe);
478 		mb_cache_entry_put(EA_INODE_CACHE(inode), oe);
479 	}
480 }
481 
482 static int
ext4_xattr_inode_verify_hashes(struct inode * ea_inode,struct ext4_xattr_entry * entry,void * buffer,size_t size)483 ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
484 			       struct ext4_xattr_entry *entry, void *buffer,
485 			       size_t size)
486 {
487 	u32 hash;
488 
489 	/* Verify stored hash matches calculated hash. */
490 	hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
491 	if (hash != ext4_xattr_inode_get_hash(ea_inode))
492 		return -EFSCORRUPTED;
493 
494 	if (entry) {
495 		__le32 e_hash, tmp_data;
496 
497 		/* Verify entry hash. */
498 		tmp_data = cpu_to_le32(hash);
499 		e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
500 					       &tmp_data, 1);
501 		/* All good? */
502 		if (e_hash == entry->e_hash)
503 			return 0;
504 
505 		/*
506 		 * Not good. Maybe the entry hash was calculated
507 		 * using the buggy signed char version?
508 		 */
509 		e_hash = ext4_xattr_hash_entry_signed(entry->e_name, entry->e_name_len,
510 							&tmp_data, 1);
511 		/* Still no match - bad */
512 		if (e_hash != entry->e_hash)
513 			return -EFSCORRUPTED;
514 
515 		/* Let people know about old hash */
516 		pr_warn_once("ext4: filesystem with signed xattr name hash");
517 	}
518 	return 0;
519 }
520 
521 /*
522  * Read xattr value from the EA inode.
523  */
524 static int
ext4_xattr_inode_get(struct inode * inode,struct ext4_xattr_entry * entry,void * buffer,size_t size)525 ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
526 		     void *buffer, size_t size)
527 {
528 	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
529 	struct inode *ea_inode;
530 	int err;
531 
532 	err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
533 				    le32_to_cpu(entry->e_hash), &ea_inode);
534 	if (err) {
535 		ea_inode = NULL;
536 		goto out;
537 	}
538 
539 	if (i_size_read(ea_inode) != size) {
540 		ext4_warning_inode(ea_inode,
541 				   "ea_inode file size=%llu entry size=%zu",
542 				   i_size_read(ea_inode), size);
543 		err = -EFSCORRUPTED;
544 		goto out;
545 	}
546 
547 	err = ext4_xattr_inode_read(ea_inode, buffer, size);
548 	if (err)
549 		goto out;
550 
551 	if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
552 		err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
553 						     size);
554 		if (err) {
555 			ext4_warning_inode(ea_inode,
556 					   "EA inode hash validation failed");
557 			goto out;
558 		}
559 
560 		if (ea_inode_cache)
561 			mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
562 					ext4_xattr_inode_get_hash(ea_inode),
563 					ea_inode->i_ino, true /* reusable */);
564 	}
565 out:
566 	iput(ea_inode);
567 	return err;
568 }
569 
570 static int
ext4_xattr_block_get(struct inode * inode,int name_index,const char * name,void * buffer,size_t buffer_size)571 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
572 		     void *buffer, size_t buffer_size)
573 {
574 	struct buffer_head *bh = NULL;
575 	struct ext4_xattr_entry *entry;
576 	size_t size;
577 	void *end;
578 	int error;
579 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
580 
581 	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
582 		  name_index, name, buffer, (long)buffer_size);
583 
584 	if (!EXT4_I(inode)->i_file_acl)
585 		return -ENODATA;
586 	ea_idebug(inode, "reading block %llu",
587 		  (unsigned long long)EXT4_I(inode)->i_file_acl);
588 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
589 	if (IS_ERR(bh))
590 		return PTR_ERR(bh);
591 	ea_bdebug(bh, "b_count=%d, refcount=%d",
592 		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
593 	error = ext4_xattr_check_block(inode, bh);
594 	if (error)
595 		goto cleanup;
596 	ext4_xattr_block_cache_insert(ea_block_cache, bh);
597 	entry = BFIRST(bh);
598 	end = bh->b_data + bh->b_size;
599 	error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
600 	if (error)
601 		goto cleanup;
602 	size = le32_to_cpu(entry->e_value_size);
603 	error = -ERANGE;
604 	if (unlikely(size > EXT4_XATTR_SIZE_MAX))
605 		goto cleanup;
606 	if (buffer) {
607 		if (size > buffer_size)
608 			goto cleanup;
609 		if (entry->e_value_inum) {
610 			error = ext4_xattr_inode_get(inode, entry, buffer,
611 						     size);
612 			if (error)
613 				goto cleanup;
614 		} else {
615 			u16 offset = le16_to_cpu(entry->e_value_offs);
616 			void *p = bh->b_data + offset;
617 
618 			if (unlikely(p + size > end))
619 				goto cleanup;
620 			memcpy(buffer, p, size);
621 		}
622 	}
623 	error = size;
624 
625 cleanup:
626 	brelse(bh);
627 	return error;
628 }
629 
630 int
ext4_xattr_ibody_get(struct inode * inode,int name_index,const char * name,void * buffer,size_t buffer_size)631 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
632 		     void *buffer, size_t buffer_size)
633 {
634 	struct ext4_xattr_ibody_header *header;
635 	struct ext4_xattr_entry *entry;
636 	struct ext4_inode *raw_inode;
637 	struct ext4_iloc iloc;
638 	size_t size;
639 	void *end;
640 	int error;
641 
642 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
643 		return -ENODATA;
644 	error = ext4_get_inode_loc(inode, &iloc);
645 	if (error)
646 		return error;
647 	raw_inode = ext4_raw_inode(&iloc);
648 	header = IHDR(inode, raw_inode);
649 	end = ITAIL(inode, raw_inode);
650 	entry = IFIRST(header);
651 	error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
652 	if (error)
653 		goto cleanup;
654 	size = le32_to_cpu(entry->e_value_size);
655 	error = -ERANGE;
656 	if (unlikely(size > EXT4_XATTR_SIZE_MAX))
657 		goto cleanup;
658 	if (buffer) {
659 		if (size > buffer_size)
660 			goto cleanup;
661 		if (entry->e_value_inum) {
662 			error = ext4_xattr_inode_get(inode, entry, buffer,
663 						     size);
664 			if (error)
665 				goto cleanup;
666 		} else {
667 			u16 offset = le16_to_cpu(entry->e_value_offs);
668 			void *p = (void *)IFIRST(header) + offset;
669 
670 			if (unlikely(p + size > end))
671 				goto cleanup;
672 			memcpy(buffer, p, size);
673 		}
674 	}
675 	error = size;
676 
677 cleanup:
678 	brelse(iloc.bh);
679 	return error;
680 }
681 
682 /*
683  * ext4_xattr_get()
684  *
685  * Copy an extended attribute into the buffer
686  * provided, or compute the buffer size required.
687  * Buffer is NULL to compute the size of the buffer required.
688  *
689  * Returns a negative error number on failure, or the number of bytes
690  * used / required on success.
691  */
692 int
ext4_xattr_get(struct inode * inode,int name_index,const char * name,void * buffer,size_t buffer_size)693 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
694 	       void *buffer, size_t buffer_size)
695 {
696 	int error;
697 
698 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
699 		return -EIO;
700 
701 	if (strlen(name) > 255)
702 		return -ERANGE;
703 
704 	down_read(&EXT4_I(inode)->xattr_sem);
705 	error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
706 				     buffer_size);
707 	if (error == -ENODATA)
708 		error = ext4_xattr_block_get(inode, name_index, name, buffer,
709 					     buffer_size);
710 	up_read(&EXT4_I(inode)->xattr_sem);
711 	return error;
712 }
713 
714 static int
ext4_xattr_list_entries(struct dentry * dentry,struct ext4_xattr_entry * entry,char * buffer,size_t buffer_size)715 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
716 			char *buffer, size_t buffer_size)
717 {
718 	size_t rest = buffer_size;
719 
720 	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
721 		const char *prefix;
722 
723 		prefix = ext4_xattr_prefix(entry->e_name_index, dentry);
724 		if (prefix) {
725 			size_t prefix_len = strlen(prefix);
726 			size_t size = prefix_len + entry->e_name_len + 1;
727 
728 			if (buffer) {
729 				if (size > rest)
730 					return -ERANGE;
731 				memcpy(buffer, prefix, prefix_len);
732 				buffer += prefix_len;
733 				memcpy(buffer, entry->e_name, entry->e_name_len);
734 				buffer += entry->e_name_len;
735 				*buffer++ = 0;
736 			}
737 			rest -= size;
738 		}
739 	}
740 	return buffer_size - rest;  /* total size */
741 }
742 
743 static int
ext4_xattr_block_list(struct dentry * dentry,char * buffer,size_t buffer_size)744 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
745 {
746 	struct inode *inode = d_inode(dentry);
747 	struct buffer_head *bh = NULL;
748 	int error;
749 
750 	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
751 		  buffer, (long)buffer_size);
752 
753 	if (!EXT4_I(inode)->i_file_acl)
754 		return 0;
755 	ea_idebug(inode, "reading block %llu",
756 		  (unsigned long long)EXT4_I(inode)->i_file_acl);
757 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
758 	if (IS_ERR(bh))
759 		return PTR_ERR(bh);
760 	ea_bdebug(bh, "b_count=%d, refcount=%d",
761 		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
762 	error = ext4_xattr_check_block(inode, bh);
763 	if (error)
764 		goto cleanup;
765 	ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
766 	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
767 					buffer_size);
768 cleanup:
769 	brelse(bh);
770 	return error;
771 }
772 
773 static int
ext4_xattr_ibody_list(struct dentry * dentry,char * buffer,size_t buffer_size)774 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
775 {
776 	struct inode *inode = d_inode(dentry);
777 	struct ext4_xattr_ibody_header *header;
778 	struct ext4_inode *raw_inode;
779 	struct ext4_iloc iloc;
780 	int error;
781 
782 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
783 		return 0;
784 	error = ext4_get_inode_loc(inode, &iloc);
785 	if (error)
786 		return error;
787 	raw_inode = ext4_raw_inode(&iloc);
788 	header = IHDR(inode, raw_inode);
789 	error = ext4_xattr_list_entries(dentry, IFIRST(header),
790 					buffer, buffer_size);
791 
792 	brelse(iloc.bh);
793 	return error;
794 }
795 
796 /*
797  * Inode operation listxattr()
798  *
799  * d_inode(dentry)->i_rwsem: don't care
800  *
801  * Copy a list of attribute names into the buffer
802  * provided, or compute the buffer size required.
803  * Buffer is NULL to compute the size of the buffer required.
804  *
805  * Returns a negative error number on failure, or the number of bytes
806  * used / required on success.
807  */
808 ssize_t
ext4_listxattr(struct dentry * dentry,char * buffer,size_t buffer_size)809 ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
810 {
811 	int ret, ret2;
812 
813 	down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
814 	ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
815 	if (ret < 0)
816 		goto errout;
817 	if (buffer) {
818 		buffer += ret;
819 		buffer_size -= ret;
820 	}
821 	ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
822 	if (ret < 0)
823 		goto errout;
824 	ret += ret2;
825 errout:
826 	up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
827 	return ret;
828 }
829 
830 /*
831  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
832  * not set, set it.
833  */
ext4_xattr_update_super_block(handle_t * handle,struct super_block * sb)834 static void ext4_xattr_update_super_block(handle_t *handle,
835 					  struct super_block *sb)
836 {
837 	if (ext4_has_feature_xattr(sb))
838 		return;
839 
840 	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
841 	if (ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
842 					  EXT4_JTR_NONE) == 0) {
843 		lock_buffer(EXT4_SB(sb)->s_sbh);
844 		ext4_set_feature_xattr(sb);
845 		ext4_superblock_csum_set(sb);
846 		unlock_buffer(EXT4_SB(sb)->s_sbh);
847 		ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
848 	}
849 }
850 
ext4_get_inode_usage(struct inode * inode,qsize_t * usage)851 int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
852 {
853 	struct ext4_iloc iloc = { .bh = NULL };
854 	struct buffer_head *bh = NULL;
855 	struct ext4_inode *raw_inode;
856 	struct ext4_xattr_ibody_header *header;
857 	struct ext4_xattr_entry *entry;
858 	qsize_t ea_inode_refs = 0;
859 	int ret;
860 
861 	lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
862 
863 	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
864 		ret = ext4_get_inode_loc(inode, &iloc);
865 		if (ret)
866 			goto out;
867 		raw_inode = ext4_raw_inode(&iloc);
868 		header = IHDR(inode, raw_inode);
869 
870 		for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
871 		     entry = EXT4_XATTR_NEXT(entry))
872 			if (entry->e_value_inum)
873 				ea_inode_refs++;
874 	}
875 
876 	if (EXT4_I(inode)->i_file_acl) {
877 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
878 		if (IS_ERR(bh)) {
879 			ret = PTR_ERR(bh);
880 			bh = NULL;
881 			goto out;
882 		}
883 
884 		ret = ext4_xattr_check_block(inode, bh);
885 		if (ret)
886 			goto out;
887 
888 		for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
889 		     entry = EXT4_XATTR_NEXT(entry))
890 			if (entry->e_value_inum)
891 				ea_inode_refs++;
892 	}
893 	*usage = ea_inode_refs + 1;
894 	ret = 0;
895 out:
896 	brelse(iloc.bh);
897 	brelse(bh);
898 	return ret;
899 }
900 
round_up_cluster(struct inode * inode,size_t length)901 static inline size_t round_up_cluster(struct inode *inode, size_t length)
902 {
903 	struct super_block *sb = inode->i_sb;
904 	size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
905 				    inode->i_blkbits);
906 	size_t mask = ~(cluster_size - 1);
907 
908 	return (length + cluster_size - 1) & mask;
909 }
910 
ext4_xattr_inode_alloc_quota(struct inode * inode,size_t len)911 static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
912 {
913 	int err;
914 
915 	err = dquot_alloc_inode(inode);
916 	if (err)
917 		return err;
918 	err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
919 	if (err)
920 		dquot_free_inode(inode);
921 	return err;
922 }
923 
ext4_xattr_inode_free_quota(struct inode * parent,struct inode * ea_inode,size_t len)924 static void ext4_xattr_inode_free_quota(struct inode *parent,
925 					struct inode *ea_inode,
926 					size_t len)
927 {
928 	if (ea_inode &&
929 	    ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
930 		return;
931 	dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
932 	dquot_free_inode(parent);
933 }
934 
__ext4_xattr_set_credits(struct super_block * sb,struct inode * inode,struct buffer_head * block_bh,size_t value_len,bool is_create)935 int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
936 			     struct buffer_head *block_bh, size_t value_len,
937 			     bool is_create)
938 {
939 	int credits;
940 	int blocks;
941 
942 	/*
943 	 * 1) Owner inode update
944 	 * 2) Ref count update on old xattr block
945 	 * 3) new xattr block
946 	 * 4) block bitmap update for new xattr block
947 	 * 5) group descriptor for new xattr block
948 	 * 6) block bitmap update for old xattr block
949 	 * 7) group descriptor for old block
950 	 *
951 	 * 6 & 7 can happen if we have two racing threads T_a and T_b
952 	 * which are each trying to set an xattr on inodes I_a and I_b
953 	 * which were both initially sharing an xattr block.
954 	 */
955 	credits = 7;
956 
957 	/* Quota updates. */
958 	credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
959 
960 	/*
961 	 * In case of inline data, we may push out the data to a block,
962 	 * so we need to reserve credits for this eventuality
963 	 */
964 	if (inode && ext4_has_inline_data(inode))
965 		credits += ext4_writepage_trans_blocks(inode) + 1;
966 
967 	/* We are done if ea_inode feature is not enabled. */
968 	if (!ext4_has_feature_ea_inode(sb))
969 		return credits;
970 
971 	/* New ea_inode, inode map, block bitmap, group descriptor. */
972 	credits += 4;
973 
974 	/* Data blocks. */
975 	blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
976 
977 	/* Indirection block or one level of extent tree. */
978 	blocks += 1;
979 
980 	/* Block bitmap and group descriptor updates for each block. */
981 	credits += blocks * 2;
982 
983 	/* Blocks themselves. */
984 	credits += blocks;
985 
986 	if (!is_create) {
987 		/* Dereference ea_inode holding old xattr value.
988 		 * Old ea_inode, inode map, block bitmap, group descriptor.
989 		 */
990 		credits += 4;
991 
992 		/* Data blocks for old ea_inode. */
993 		blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
994 
995 		/* Indirection block or one level of extent tree for old
996 		 * ea_inode.
997 		 */
998 		blocks += 1;
999 
1000 		/* Block bitmap and group descriptor updates for each block. */
1001 		credits += blocks * 2;
1002 	}
1003 
1004 	/* We may need to clone the existing xattr block in which case we need
1005 	 * to increment ref counts for existing ea_inodes referenced by it.
1006 	 */
1007 	if (block_bh) {
1008 		struct ext4_xattr_entry *entry = BFIRST(block_bh);
1009 
1010 		for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
1011 			if (entry->e_value_inum)
1012 				/* Ref count update on ea_inode. */
1013 				credits += 1;
1014 	}
1015 	return credits;
1016 }
1017 
ext4_xattr_inode_update_ref(handle_t * handle,struct inode * ea_inode,int ref_change)1018 static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
1019 				       int ref_change)
1020 {
1021 	struct ext4_iloc iloc;
1022 	s64 ref_count;
1023 	int ret;
1024 
1025 	inode_lock_nested(ea_inode, I_MUTEX_XATTR);
1026 
1027 	ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
1028 	if (ret)
1029 		goto out;
1030 
1031 	ref_count = ext4_xattr_inode_get_ref(ea_inode);
1032 	ref_count += ref_change;
1033 	ext4_xattr_inode_set_ref(ea_inode, ref_count);
1034 
1035 	if (ref_change > 0) {
1036 		WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
1037 			  ea_inode->i_ino, ref_count);
1038 
1039 		if (ref_count == 1) {
1040 			WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1041 				  ea_inode->i_ino, ea_inode->i_nlink);
1042 
1043 			set_nlink(ea_inode, 1);
1044 			ext4_orphan_del(handle, ea_inode);
1045 		}
1046 	} else {
1047 		WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1048 			  ea_inode->i_ino, ref_count);
1049 
1050 		if (ref_count == 0) {
1051 			WARN_ONCE(ea_inode->i_nlink != 1,
1052 				  "EA inode %lu i_nlink=%u",
1053 				  ea_inode->i_ino, ea_inode->i_nlink);
1054 
1055 			clear_nlink(ea_inode);
1056 			ext4_orphan_add(handle, ea_inode);
1057 		}
1058 	}
1059 
1060 	ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1061 	if (ret)
1062 		ext4_warning_inode(ea_inode,
1063 				   "ext4_mark_iloc_dirty() failed ret=%d", ret);
1064 out:
1065 	inode_unlock(ea_inode);
1066 	return ret;
1067 }
1068 
ext4_xattr_inode_inc_ref(handle_t * handle,struct inode * ea_inode)1069 static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1070 {
1071 	return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1072 }
1073 
ext4_xattr_inode_dec_ref(handle_t * handle,struct inode * ea_inode)1074 static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1075 {
1076 	return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1077 }
1078 
ext4_xattr_inode_inc_ref_all(handle_t * handle,struct inode * parent,struct ext4_xattr_entry * first)1079 static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1080 					struct ext4_xattr_entry *first)
1081 {
1082 	struct inode *ea_inode;
1083 	struct ext4_xattr_entry *entry;
1084 	struct ext4_xattr_entry *failed_entry;
1085 	unsigned int ea_ino;
1086 	int err, saved_err;
1087 
1088 	for (entry = first; !IS_LAST_ENTRY(entry);
1089 	     entry = EXT4_XATTR_NEXT(entry)) {
1090 		if (!entry->e_value_inum)
1091 			continue;
1092 		ea_ino = le32_to_cpu(entry->e_value_inum);
1093 		err = ext4_xattr_inode_iget(parent, ea_ino,
1094 					    le32_to_cpu(entry->e_hash),
1095 					    &ea_inode);
1096 		if (err)
1097 			goto cleanup;
1098 		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1099 		if (err) {
1100 			ext4_warning_inode(ea_inode, "inc ref error %d", err);
1101 			iput(ea_inode);
1102 			goto cleanup;
1103 		}
1104 		iput(ea_inode);
1105 	}
1106 	return 0;
1107 
1108 cleanup:
1109 	saved_err = err;
1110 	failed_entry = entry;
1111 
1112 	for (entry = first; entry != failed_entry;
1113 	     entry = EXT4_XATTR_NEXT(entry)) {
1114 		if (!entry->e_value_inum)
1115 			continue;
1116 		ea_ino = le32_to_cpu(entry->e_value_inum);
1117 		err = ext4_xattr_inode_iget(parent, ea_ino,
1118 					    le32_to_cpu(entry->e_hash),
1119 					    &ea_inode);
1120 		if (err) {
1121 			ext4_warning(parent->i_sb,
1122 				     "cleanup ea_ino %u iget error %d", ea_ino,
1123 				     err);
1124 			continue;
1125 		}
1126 		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1127 		if (err)
1128 			ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1129 					   err);
1130 		iput(ea_inode);
1131 	}
1132 	return saved_err;
1133 }
1134 
ext4_xattr_restart_fn(handle_t * handle,struct inode * inode,struct buffer_head * bh,bool block_csum,bool dirty)1135 static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1136 			struct buffer_head *bh, bool block_csum, bool dirty)
1137 {
1138 	int error;
1139 
1140 	if (bh && dirty) {
1141 		if (block_csum)
1142 			ext4_xattr_block_csum_set(inode, bh);
1143 		error = ext4_handle_dirty_metadata(handle, NULL, bh);
1144 		if (error) {
1145 			ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1146 				     error);
1147 			return error;
1148 		}
1149 	}
1150 	return 0;
1151 }
1152 
1153 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)1154 ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1155 			     struct buffer_head *bh,
1156 			     struct ext4_xattr_entry *first, bool block_csum,
1157 			     struct ext4_xattr_inode_array **ea_inode_array,
1158 			     int extra_credits, bool skip_quota)
1159 {
1160 	struct inode *ea_inode;
1161 	struct ext4_xattr_entry *entry;
1162 	struct ext4_iloc iloc;
1163 	bool dirty = false;
1164 	unsigned int ea_ino;
1165 	int err;
1166 	int credits;
1167 	void *end;
1168 
1169 	if (block_csum)
1170 		end = (void *)bh->b_data + bh->b_size;
1171 	else {
1172 		ext4_get_inode_loc(parent, &iloc);
1173 		end = (void *)ext4_raw_inode(&iloc) + EXT4_SB(parent->i_sb)->s_inode_size;
1174 	}
1175 
1176 	/* One credit for dec ref on ea_inode, one for orphan list addition, */
1177 	credits = 2 + extra_credits;
1178 
1179 	for (entry = first; (void *)entry < end && !IS_LAST_ENTRY(entry);
1180 	     entry = EXT4_XATTR_NEXT(entry)) {
1181 		if (!entry->e_value_inum)
1182 			continue;
1183 		ea_ino = le32_to_cpu(entry->e_value_inum);
1184 		err = ext4_xattr_inode_iget(parent, ea_ino,
1185 					    le32_to_cpu(entry->e_hash),
1186 					    &ea_inode);
1187 		if (err)
1188 			continue;
1189 
1190 		err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1191 		if (err) {
1192 			ext4_warning_inode(ea_inode,
1193 					   "Expand inode array err=%d", err);
1194 			iput(ea_inode);
1195 			continue;
1196 		}
1197 
1198 		err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1199 			ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1200 			ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1201 					      dirty));
1202 		if (err < 0) {
1203 			ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1204 					   err);
1205 			continue;
1206 		}
1207 		if (err > 0) {
1208 			err = ext4_journal_get_write_access(handle,
1209 					parent->i_sb, bh, EXT4_JTR_NONE);
1210 			if (err) {
1211 				ext4_warning_inode(ea_inode,
1212 						"Re-get write access err=%d",
1213 						err);
1214 				continue;
1215 			}
1216 		}
1217 
1218 		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1219 		if (err) {
1220 			ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1221 					   err);
1222 			continue;
1223 		}
1224 
1225 		if (!skip_quota)
1226 			ext4_xattr_inode_free_quota(parent, ea_inode,
1227 					      le32_to_cpu(entry->e_value_size));
1228 
1229 		/*
1230 		 * Forget about ea_inode within the same transaction that
1231 		 * decrements the ref count. This avoids duplicate decrements in
1232 		 * case the rest of the work spills over to subsequent
1233 		 * transactions.
1234 		 */
1235 		entry->e_value_inum = 0;
1236 		entry->e_value_size = 0;
1237 
1238 		dirty = true;
1239 	}
1240 
1241 	if (dirty) {
1242 		/*
1243 		 * Note that we are deliberately skipping csum calculation for
1244 		 * the final update because we do not expect any journal
1245 		 * restarts until xattr block is freed.
1246 		 */
1247 
1248 		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1249 		if (err)
1250 			ext4_warning_inode(parent,
1251 					   "handle dirty metadata err=%d", err);
1252 	}
1253 }
1254 
1255 /*
1256  * Release the xattr block BH: If the reference count is > 1, decrement it;
1257  * otherwise free the block.
1258  */
1259 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)1260 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1261 			 struct buffer_head *bh,
1262 			 struct ext4_xattr_inode_array **ea_inode_array,
1263 			 int extra_credits)
1264 {
1265 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1266 	u32 hash, ref;
1267 	int error = 0;
1268 
1269 	BUFFER_TRACE(bh, "get_write_access");
1270 	error = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1271 					      EXT4_JTR_NONE);
1272 	if (error)
1273 		goto out;
1274 
1275 retry_ref:
1276 	lock_buffer(bh);
1277 	hash = le32_to_cpu(BHDR(bh)->h_hash);
1278 	ref = le32_to_cpu(BHDR(bh)->h_refcount);
1279 	if (ref == 1) {
1280 		ea_bdebug(bh, "refcount now=0; freeing");
1281 		/*
1282 		 * This must happen under buffer lock for
1283 		 * ext4_xattr_block_set() to reliably detect freed block
1284 		 */
1285 		if (ea_block_cache) {
1286 			struct mb_cache_entry *oe;
1287 
1288 			oe = mb_cache_entry_delete_or_get(ea_block_cache, hash,
1289 							  bh->b_blocknr);
1290 			if (oe) {
1291 				unlock_buffer(bh);
1292 				mb_cache_entry_wait_unused(oe);
1293 				mb_cache_entry_put(ea_block_cache, oe);
1294 				goto retry_ref;
1295 			}
1296 		}
1297 		get_bh(bh);
1298 		unlock_buffer(bh);
1299 
1300 		if (ext4_has_feature_ea_inode(inode->i_sb))
1301 			ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1302 						     BFIRST(bh),
1303 						     true /* block_csum */,
1304 						     ea_inode_array,
1305 						     extra_credits,
1306 						     true /* skip_quota */);
1307 		ext4_free_blocks(handle, inode, bh, 0, 1,
1308 				 EXT4_FREE_BLOCKS_METADATA |
1309 				 EXT4_FREE_BLOCKS_FORGET);
1310 	} else {
1311 		ref--;
1312 		BHDR(bh)->h_refcount = cpu_to_le32(ref);
1313 		if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1314 			struct mb_cache_entry *ce;
1315 
1316 			if (ea_block_cache) {
1317 				ce = mb_cache_entry_get(ea_block_cache, hash,
1318 							bh->b_blocknr);
1319 				if (ce) {
1320 					set_bit(MBE_REUSABLE_B, &ce->e_flags);
1321 					mb_cache_entry_put(ea_block_cache, ce);
1322 				}
1323 			}
1324 		}
1325 
1326 		ext4_xattr_block_csum_set(inode, bh);
1327 		/*
1328 		 * Beware of this ugliness: Releasing of xattr block references
1329 		 * from different inodes can race and so we have to protect
1330 		 * from a race where someone else frees the block (and releases
1331 		 * its journal_head) before we are done dirtying the buffer. In
1332 		 * nojournal mode this race is harmless and we actually cannot
1333 		 * call ext4_handle_dirty_metadata() with locked buffer as
1334 		 * that function can call sync_dirty_buffer() so for that case
1335 		 * we handle the dirtying after unlocking the buffer.
1336 		 */
1337 		if (ext4_handle_valid(handle))
1338 			error = ext4_handle_dirty_metadata(handle, inode, bh);
1339 		unlock_buffer(bh);
1340 		if (!ext4_handle_valid(handle))
1341 			error = ext4_handle_dirty_metadata(handle, inode, bh);
1342 		if (IS_SYNC(inode))
1343 			ext4_handle_sync(handle);
1344 		dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1345 		ea_bdebug(bh, "refcount now=%d; releasing",
1346 			  le32_to_cpu(BHDR(bh)->h_refcount));
1347 	}
1348 out:
1349 	ext4_std_error(inode->i_sb, error);
1350 	return;
1351 }
1352 
1353 /*
1354  * Find the available free space for EAs. This also returns the total number of
1355  * bytes used by EA entries.
1356  */
ext4_xattr_free_space(struct ext4_xattr_entry * last,size_t * min_offs,void * base,int * total)1357 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1358 				    size_t *min_offs, void *base, int *total)
1359 {
1360 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1361 		if (!last->e_value_inum && last->e_value_size) {
1362 			size_t offs = le16_to_cpu(last->e_value_offs);
1363 			if (offs < *min_offs)
1364 				*min_offs = offs;
1365 		}
1366 		if (total)
1367 			*total += EXT4_XATTR_LEN(last->e_name_len);
1368 	}
1369 	return (*min_offs - ((void *)last - base) - sizeof(__u32));
1370 }
1371 
1372 /*
1373  * Write the value of the EA in an inode.
1374  */
ext4_xattr_inode_write(handle_t * handle,struct inode * ea_inode,const void * buf,int bufsize)1375 static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1376 				  const void *buf, int bufsize)
1377 {
1378 	struct buffer_head *bh = NULL;
1379 	unsigned long block = 0;
1380 	int blocksize = ea_inode->i_sb->s_blocksize;
1381 	int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1382 	int csize, wsize = 0;
1383 	int ret = 0, ret2 = 0;
1384 	int retries = 0;
1385 
1386 retry:
1387 	while (ret >= 0 && ret < max_blocks) {
1388 		struct ext4_map_blocks map;
1389 		map.m_lblk = block += ret;
1390 		map.m_len = max_blocks -= ret;
1391 
1392 		ret = ext4_map_blocks(handle, ea_inode, &map,
1393 				      EXT4_GET_BLOCKS_CREATE);
1394 		if (ret <= 0) {
1395 			ext4_mark_inode_dirty(handle, ea_inode);
1396 			if (ret == -ENOSPC &&
1397 			    ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1398 				ret = 0;
1399 				goto retry;
1400 			}
1401 			break;
1402 		}
1403 	}
1404 
1405 	if (ret < 0)
1406 		return ret;
1407 
1408 	block = 0;
1409 	while (wsize < bufsize) {
1410 		brelse(bh);
1411 		csize = (bufsize - wsize) > blocksize ? blocksize :
1412 								bufsize - wsize;
1413 		bh = ext4_getblk(handle, ea_inode, block, 0);
1414 		if (IS_ERR(bh))
1415 			return PTR_ERR(bh);
1416 		if (!bh) {
1417 			WARN_ON_ONCE(1);
1418 			EXT4_ERROR_INODE(ea_inode,
1419 					 "ext4_getblk() return bh = NULL");
1420 			return -EFSCORRUPTED;
1421 		}
1422 		ret = ext4_journal_get_write_access(handle, ea_inode->i_sb, bh,
1423 						   EXT4_JTR_NONE);
1424 		if (ret)
1425 			goto out;
1426 
1427 		memcpy(bh->b_data, buf, csize);
1428 		/*
1429 		 * Zero out block tail to avoid writing uninitialized memory
1430 		 * to disk.
1431 		 */
1432 		if (csize < blocksize)
1433 			memset(bh->b_data + csize, 0, blocksize - csize);
1434 		set_buffer_uptodate(bh);
1435 		ext4_handle_dirty_metadata(handle, ea_inode, bh);
1436 
1437 		buf += csize;
1438 		wsize += csize;
1439 		block += 1;
1440 	}
1441 
1442 	inode_lock(ea_inode);
1443 	i_size_write(ea_inode, wsize);
1444 	ext4_update_i_disksize(ea_inode, wsize);
1445 	inode_unlock(ea_inode);
1446 
1447 	ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1448 	if (unlikely(ret2 && !ret))
1449 		ret = ret2;
1450 
1451 out:
1452 	brelse(bh);
1453 
1454 	return ret;
1455 }
1456 
1457 /*
1458  * Create an inode to store the value of a large EA.
1459  */
ext4_xattr_inode_create(handle_t * handle,struct inode * inode,u32 hash)1460 static struct inode *ext4_xattr_inode_create(handle_t *handle,
1461 					     struct inode *inode, u32 hash)
1462 {
1463 	struct inode *ea_inode = NULL;
1464 	uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1465 	int err;
1466 
1467 	if (inode->i_sb->s_root == NULL) {
1468 		ext4_warning(inode->i_sb,
1469 			     "refuse to create EA inode when umounting");
1470 		WARN_ON(1);
1471 		return ERR_PTR(-EINVAL);
1472 	}
1473 
1474 	/*
1475 	 * Let the next inode be the goal, so we try and allocate the EA inode
1476 	 * in the same group, or nearby one.
1477 	 */
1478 	ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1479 				  S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1480 				  EXT4_EA_INODE_FL);
1481 	if (!IS_ERR(ea_inode)) {
1482 		ea_inode->i_op = &ext4_file_inode_operations;
1483 		ea_inode->i_fop = &ext4_file_operations;
1484 		ext4_set_aops(ea_inode);
1485 		ext4_xattr_inode_set_class(ea_inode);
1486 		unlock_new_inode(ea_inode);
1487 		ext4_xattr_inode_set_ref(ea_inode, 1);
1488 		ext4_xattr_inode_set_hash(ea_inode, hash);
1489 		err = ext4_mark_inode_dirty(handle, ea_inode);
1490 		if (!err)
1491 			err = ext4_inode_attach_jinode(ea_inode);
1492 		if (err) {
1493 			if (ext4_xattr_inode_dec_ref(handle, ea_inode))
1494 				ext4_warning_inode(ea_inode,
1495 					"cleanup dec ref error %d", err);
1496 			iput(ea_inode);
1497 			return ERR_PTR(err);
1498 		}
1499 
1500 		/*
1501 		 * Xattr inodes are shared therefore quota charging is performed
1502 		 * at a higher level.
1503 		 */
1504 		dquot_free_inode(ea_inode);
1505 		dquot_drop(ea_inode);
1506 		inode_lock(ea_inode);
1507 		ea_inode->i_flags |= S_NOQUOTA;
1508 		inode_unlock(ea_inode);
1509 	}
1510 
1511 	return ea_inode;
1512 }
1513 
1514 static struct inode *
ext4_xattr_inode_cache_find(struct inode * inode,const void * value,size_t value_len,u32 hash)1515 ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1516 			    size_t value_len, u32 hash)
1517 {
1518 	struct inode *ea_inode;
1519 	struct mb_cache_entry *ce;
1520 	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1521 	void *ea_data;
1522 
1523 	if (!ea_inode_cache)
1524 		return NULL;
1525 
1526 	ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1527 	if (!ce)
1528 		return NULL;
1529 
1530 	WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1531 		     !(current->flags & PF_MEMALLOC_NOFS));
1532 
1533 	ea_data = kvmalloc(value_len, GFP_KERNEL);
1534 	if (!ea_data) {
1535 		mb_cache_entry_put(ea_inode_cache, ce);
1536 		return NULL;
1537 	}
1538 
1539 	while (ce) {
1540 		ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1541 				     EXT4_IGET_EA_INODE);
1542 		if (IS_ERR(ea_inode))
1543 			goto next_entry;
1544 		ext4_xattr_inode_set_class(ea_inode);
1545 		if (i_size_read(ea_inode) == value_len &&
1546 		    !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1547 		    !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1548 						    value_len) &&
1549 		    !memcmp(value, ea_data, value_len)) {
1550 			mb_cache_entry_touch(ea_inode_cache, ce);
1551 			mb_cache_entry_put(ea_inode_cache, ce);
1552 			kvfree(ea_data);
1553 			return ea_inode;
1554 		}
1555 		iput(ea_inode);
1556 	next_entry:
1557 		ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1558 	}
1559 	kvfree(ea_data);
1560 	return NULL;
1561 }
1562 
1563 /*
1564  * Add value of the EA in an inode.
1565  */
ext4_xattr_inode_lookup_create(handle_t * handle,struct inode * inode,const void * value,size_t value_len)1566 static struct inode *ext4_xattr_inode_lookup_create(handle_t *handle,
1567 		struct inode *inode, const void *value, size_t value_len)
1568 {
1569 	struct inode *ea_inode;
1570 	u32 hash;
1571 	int err;
1572 
1573 	/* Account inode & space to quota even if sharing... */
1574 	err = ext4_xattr_inode_alloc_quota(inode, value_len);
1575 	if (err)
1576 		return ERR_PTR(err);
1577 
1578 	hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1579 	ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1580 	if (ea_inode) {
1581 		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1582 		if (err)
1583 			goto out_err;
1584 		return ea_inode;
1585 	}
1586 
1587 	/* Create an inode for the EA value */
1588 	ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1589 	if (IS_ERR(ea_inode)) {
1590 		ext4_xattr_inode_free_quota(inode, NULL, value_len);
1591 		return ea_inode;
1592 	}
1593 
1594 	err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1595 	if (err) {
1596 		if (ext4_xattr_inode_dec_ref(handle, ea_inode))
1597 			ext4_warning_inode(ea_inode, "cleanup dec ref error %d", err);
1598 		goto out_err;
1599 	}
1600 
1601 	if (EA_INODE_CACHE(inode))
1602 		mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1603 				      ea_inode->i_ino, true /* reusable */);
1604 	return ea_inode;
1605 out_err:
1606 	iput(ea_inode);
1607 	ext4_xattr_inode_free_quota(inode, NULL, value_len);
1608 	return ERR_PTR(err);
1609 }
1610 
1611 /*
1612  * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1613  * feature is enabled.
1614  */
1615 #define EXT4_XATTR_BLOCK_RESERVE(inode)	min(i_blocksize(inode)/8, 1024U)
1616 
ext4_xattr_set_entry(struct ext4_xattr_info * i,struct ext4_xattr_search * s,handle_t * handle,struct inode * inode,struct inode * new_ea_inode,bool is_block)1617 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1618 				struct ext4_xattr_search *s,
1619 				handle_t *handle, struct inode *inode,
1620 				struct inode *new_ea_inode,
1621 				bool is_block)
1622 {
1623 	struct ext4_xattr_entry *last, *next;
1624 	struct ext4_xattr_entry *here = s->here;
1625 	size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1626 	int in_inode = i->in_inode;
1627 	struct inode *old_ea_inode = NULL;
1628 	size_t old_size, new_size;
1629 	int ret;
1630 
1631 	/* Space used by old and new values. */
1632 	old_size = (!s->not_found && !here->e_value_inum) ?
1633 			EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1634 	new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1635 
1636 	/*
1637 	 * Optimization for the simple case when old and new values have the
1638 	 * same padded sizes. Not applicable if external inodes are involved.
1639 	 */
1640 	if (new_size && new_size == old_size) {
1641 		size_t offs = le16_to_cpu(here->e_value_offs);
1642 		void *val = s->base + offs;
1643 
1644 		here->e_value_size = cpu_to_le32(i->value_len);
1645 		if (i->value == EXT4_ZERO_XATTR_VALUE) {
1646 			memset(val, 0, new_size);
1647 		} else {
1648 			memcpy(val, i->value, i->value_len);
1649 			/* Clear padding bytes. */
1650 			memset(val + i->value_len, 0, new_size - i->value_len);
1651 		}
1652 		goto update_hash;
1653 	}
1654 
1655 	/* Compute min_offs and last. */
1656 	last = s->first;
1657 	for (; !IS_LAST_ENTRY(last); last = next) {
1658 		next = EXT4_XATTR_NEXT(last);
1659 		if ((void *)next >= s->end) {
1660 			EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1661 			ret = -EFSCORRUPTED;
1662 			goto out;
1663 		}
1664 		if (!last->e_value_inum && last->e_value_size) {
1665 			size_t offs = le16_to_cpu(last->e_value_offs);
1666 			if (offs < min_offs)
1667 				min_offs = offs;
1668 		}
1669 	}
1670 
1671 	/* Check whether we have enough space. */
1672 	if (i->value) {
1673 		size_t free;
1674 
1675 		free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1676 		if (!s->not_found)
1677 			free += EXT4_XATTR_LEN(name_len) + old_size;
1678 
1679 		if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1680 			ret = -ENOSPC;
1681 			goto out;
1682 		}
1683 
1684 		/*
1685 		 * If storing the value in an external inode is an option,
1686 		 * reserve space for xattr entries/names in the external
1687 		 * attribute block so that a long value does not occupy the
1688 		 * whole space and prevent further entries being added.
1689 		 */
1690 		if (ext4_has_feature_ea_inode(inode->i_sb) &&
1691 		    new_size && is_block &&
1692 		    (min_offs + old_size - new_size) <
1693 					EXT4_XATTR_BLOCK_RESERVE(inode)) {
1694 			ret = -ENOSPC;
1695 			goto out;
1696 		}
1697 	}
1698 
1699 	/*
1700 	 * Getting access to old and new ea inodes is subject to failures.
1701 	 * Finish that work before doing any modifications to the xattr data.
1702 	 */
1703 	if (!s->not_found && here->e_value_inum) {
1704 		ret = ext4_xattr_inode_iget(inode,
1705 					    le32_to_cpu(here->e_value_inum),
1706 					    le32_to_cpu(here->e_hash),
1707 					    &old_ea_inode);
1708 		if (ret) {
1709 			old_ea_inode = NULL;
1710 			goto out;
1711 		}
1712 
1713 		/* We are ready to release ref count on the old_ea_inode. */
1714 		ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1715 		if (ret)
1716 			goto out;
1717 
1718 		ext4_xattr_inode_free_quota(inode, old_ea_inode,
1719 					    le32_to_cpu(here->e_value_size));
1720 	}
1721 
1722 	/* No failures allowed past this point. */
1723 
1724 	if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1725 		/* Remove the old value. */
1726 		void *first_val = s->base + min_offs;
1727 		size_t offs = le16_to_cpu(here->e_value_offs);
1728 		void *val = s->base + offs;
1729 
1730 		memmove(first_val + old_size, first_val, val - first_val);
1731 		memset(first_val, 0, old_size);
1732 		min_offs += old_size;
1733 
1734 		/* Adjust all value offsets. */
1735 		last = s->first;
1736 		while (!IS_LAST_ENTRY(last)) {
1737 			size_t o = le16_to_cpu(last->e_value_offs);
1738 
1739 			if (!last->e_value_inum &&
1740 			    last->e_value_size && o < offs)
1741 				last->e_value_offs = cpu_to_le16(o + old_size);
1742 			last = EXT4_XATTR_NEXT(last);
1743 		}
1744 	}
1745 
1746 	if (!i->value) {
1747 		/* Remove old name. */
1748 		size_t size = EXT4_XATTR_LEN(name_len);
1749 
1750 		last = ENTRY((void *)last - size);
1751 		memmove(here, (void *)here + size,
1752 			(void *)last - (void *)here + sizeof(__u32));
1753 		memset(last, 0, size);
1754 
1755 		/*
1756 		 * Update i_inline_off - moved ibody region might contain
1757 		 * system.data attribute.  Handling a failure here won't
1758 		 * cause other complications for setting an xattr.
1759 		 */
1760 		if (!is_block && ext4_has_inline_data(inode)) {
1761 			ret = ext4_find_inline_data_nolock(inode);
1762 			if (ret) {
1763 				ext4_warning_inode(inode,
1764 					"unable to update i_inline_off");
1765 				goto out;
1766 			}
1767 		}
1768 	} else if (s->not_found) {
1769 		/* Insert new name. */
1770 		size_t size = EXT4_XATTR_LEN(name_len);
1771 		size_t rest = (void *)last - (void *)here + sizeof(__u32);
1772 
1773 		memmove((void *)here + size, here, rest);
1774 		memset(here, 0, size);
1775 		here->e_name_index = i->name_index;
1776 		here->e_name_len = name_len;
1777 		memcpy(here->e_name, i->name, name_len);
1778 	} else {
1779 		/* This is an update, reset value info. */
1780 		here->e_value_inum = 0;
1781 		here->e_value_offs = 0;
1782 		here->e_value_size = 0;
1783 	}
1784 
1785 	if (i->value) {
1786 		/* Insert new value. */
1787 		if (in_inode) {
1788 			here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1789 		} else if (i->value_len) {
1790 			void *val = s->base + min_offs - new_size;
1791 
1792 			here->e_value_offs = cpu_to_le16(min_offs - new_size);
1793 			if (i->value == EXT4_ZERO_XATTR_VALUE) {
1794 				memset(val, 0, new_size);
1795 			} else {
1796 				memcpy(val, i->value, i->value_len);
1797 				/* Clear padding bytes. */
1798 				memset(val + i->value_len, 0,
1799 				       new_size - i->value_len);
1800 			}
1801 		}
1802 		here->e_value_size = cpu_to_le32(i->value_len);
1803 	}
1804 
1805 update_hash:
1806 	if (i->value) {
1807 		__le32 hash = 0;
1808 
1809 		/* Entry hash calculation. */
1810 		if (in_inode) {
1811 			__le32 crc32c_hash;
1812 
1813 			/*
1814 			 * Feed crc32c hash instead of the raw value for entry
1815 			 * hash calculation. This is to avoid walking
1816 			 * potentially long value buffer again.
1817 			 */
1818 			crc32c_hash = cpu_to_le32(
1819 				       ext4_xattr_inode_get_hash(new_ea_inode));
1820 			hash = ext4_xattr_hash_entry(here->e_name,
1821 						     here->e_name_len,
1822 						     &crc32c_hash, 1);
1823 		} else if (is_block) {
1824 			__le32 *value = s->base + le16_to_cpu(
1825 							here->e_value_offs);
1826 
1827 			hash = ext4_xattr_hash_entry(here->e_name,
1828 						     here->e_name_len, value,
1829 						     new_size >> 2);
1830 		}
1831 		here->e_hash = hash;
1832 	}
1833 
1834 	if (is_block)
1835 		ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1836 
1837 	ret = 0;
1838 out:
1839 	iput(old_ea_inode);
1840 	return ret;
1841 }
1842 
1843 struct ext4_xattr_block_find {
1844 	struct ext4_xattr_search s;
1845 	struct buffer_head *bh;
1846 };
1847 
1848 static int
ext4_xattr_block_find(struct inode * inode,struct ext4_xattr_info * i,struct ext4_xattr_block_find * bs)1849 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1850 		      struct ext4_xattr_block_find *bs)
1851 {
1852 	struct super_block *sb = inode->i_sb;
1853 	int error;
1854 
1855 	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1856 		  i->name_index, i->name, i->value, (long)i->value_len);
1857 
1858 	if (EXT4_I(inode)->i_file_acl) {
1859 		/* The inode already has an extended attribute block. */
1860 		bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1861 		if (IS_ERR(bs->bh)) {
1862 			error = PTR_ERR(bs->bh);
1863 			bs->bh = NULL;
1864 			return error;
1865 		}
1866 		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1867 			atomic_read(&(bs->bh->b_count)),
1868 			le32_to_cpu(BHDR(bs->bh)->h_refcount));
1869 		error = ext4_xattr_check_block(inode, bs->bh);
1870 		if (error)
1871 			return error;
1872 		/* Find the named attribute. */
1873 		bs->s.base = BHDR(bs->bh);
1874 		bs->s.first = BFIRST(bs->bh);
1875 		bs->s.end = bs->bh->b_data + bs->bh->b_size;
1876 		bs->s.here = bs->s.first;
1877 		error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1878 					 i->name_index, i->name, 1);
1879 		if (error && error != -ENODATA)
1880 			return error;
1881 		bs->s.not_found = error;
1882 	}
1883 	return 0;
1884 }
1885 
1886 static int
ext4_xattr_block_set(handle_t * handle,struct inode * inode,struct ext4_xattr_info * i,struct ext4_xattr_block_find * bs)1887 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1888 		     struct ext4_xattr_info *i,
1889 		     struct ext4_xattr_block_find *bs)
1890 {
1891 	struct super_block *sb = inode->i_sb;
1892 	struct buffer_head *new_bh = NULL;
1893 	struct ext4_xattr_search s_copy = bs->s;
1894 	struct ext4_xattr_search *s = &s_copy;
1895 	struct mb_cache_entry *ce = NULL;
1896 	int error = 0;
1897 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1898 	struct inode *ea_inode = NULL, *tmp_inode;
1899 	size_t old_ea_inode_quota = 0;
1900 	unsigned int ea_ino;
1901 
1902 #define header(x) ((struct ext4_xattr_header *)(x))
1903 
1904 	/* If we need EA inode, prepare it before locking the buffer */
1905 	if (i->value && i->in_inode) {
1906 		WARN_ON_ONCE(!i->value_len);
1907 
1908 		ea_inode = ext4_xattr_inode_lookup_create(handle, inode,
1909 					i->value, i->value_len);
1910 		if (IS_ERR(ea_inode)) {
1911 			error = PTR_ERR(ea_inode);
1912 			ea_inode = NULL;
1913 			goto cleanup;
1914 		}
1915 	}
1916 
1917 	if (s->base) {
1918 		int offset = (char *)s->here - bs->bh->b_data;
1919 
1920 		BUFFER_TRACE(bs->bh, "get_write_access");
1921 		error = ext4_journal_get_write_access(handle, sb, bs->bh,
1922 						      EXT4_JTR_NONE);
1923 		if (error)
1924 			goto cleanup;
1925 
1926 		lock_buffer(bs->bh);
1927 
1928 		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1929 			__u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1930 
1931 			/*
1932 			 * This must happen under buffer lock for
1933 			 * ext4_xattr_block_set() to reliably detect modified
1934 			 * block
1935 			 */
1936 			if (ea_block_cache) {
1937 				struct mb_cache_entry *oe;
1938 
1939 				oe = mb_cache_entry_delete_or_get(ea_block_cache,
1940 					hash, bs->bh->b_blocknr);
1941 				if (oe) {
1942 					/*
1943 					 * Xattr block is getting reused. Leave
1944 					 * it alone.
1945 					 */
1946 					mb_cache_entry_put(ea_block_cache, oe);
1947 					goto clone_block;
1948 				}
1949 			}
1950 			ea_bdebug(bs->bh, "modifying in-place");
1951 			error = ext4_xattr_set_entry(i, s, handle, inode,
1952 					     ea_inode, true /* is_block */);
1953 			ext4_xattr_block_csum_set(inode, bs->bh);
1954 			unlock_buffer(bs->bh);
1955 			if (error == -EFSCORRUPTED)
1956 				goto bad_block;
1957 			if (!error)
1958 				error = ext4_handle_dirty_metadata(handle,
1959 								   inode,
1960 								   bs->bh);
1961 			if (error)
1962 				goto cleanup;
1963 			goto inserted;
1964 		}
1965 clone_block:
1966 		unlock_buffer(bs->bh);
1967 		ea_bdebug(bs->bh, "cloning");
1968 		s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
1969 		error = -ENOMEM;
1970 		if (s->base == NULL)
1971 			goto cleanup;
1972 		s->first = ENTRY(header(s->base)+1);
1973 		header(s->base)->h_refcount = cpu_to_le32(1);
1974 		s->here = ENTRY(s->base + offset);
1975 		s->end = s->base + bs->bh->b_size;
1976 
1977 		/*
1978 		 * If existing entry points to an xattr inode, we need
1979 		 * to prevent ext4_xattr_set_entry() from decrementing
1980 		 * ref count on it because the reference belongs to the
1981 		 * original block. In this case, make the entry look
1982 		 * like it has an empty value.
1983 		 */
1984 		if (!s->not_found && s->here->e_value_inum) {
1985 			ea_ino = le32_to_cpu(s->here->e_value_inum);
1986 			error = ext4_xattr_inode_iget(inode, ea_ino,
1987 				      le32_to_cpu(s->here->e_hash),
1988 				      &tmp_inode);
1989 			if (error)
1990 				goto cleanup;
1991 
1992 			if (!ext4_test_inode_state(tmp_inode,
1993 					EXT4_STATE_LUSTRE_EA_INODE)) {
1994 				/*
1995 				 * Defer quota free call for previous
1996 				 * inode until success is guaranteed.
1997 				 */
1998 				old_ea_inode_quota = le32_to_cpu(
1999 						s->here->e_value_size);
2000 			}
2001 			iput(tmp_inode);
2002 
2003 			s->here->e_value_inum = 0;
2004 			s->here->e_value_size = 0;
2005 		}
2006 	} else {
2007 		/* Allocate a buffer where we construct the new block. */
2008 		s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
2009 		error = -ENOMEM;
2010 		if (s->base == NULL)
2011 			goto cleanup;
2012 		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2013 		header(s->base)->h_blocks = cpu_to_le32(1);
2014 		header(s->base)->h_refcount = cpu_to_le32(1);
2015 		s->first = ENTRY(header(s->base)+1);
2016 		s->here = ENTRY(header(s->base)+1);
2017 		s->end = s->base + sb->s_blocksize;
2018 	}
2019 
2020 	error = ext4_xattr_set_entry(i, s, handle, inode, ea_inode,
2021 				     true /* is_block */);
2022 	if (error == -EFSCORRUPTED)
2023 		goto bad_block;
2024 	if (error)
2025 		goto cleanup;
2026 
2027 inserted:
2028 	if (!IS_LAST_ENTRY(s->first)) {
2029 		new_bh = ext4_xattr_block_cache_find(inode, header(s->base), &ce);
2030 		if (IS_ERR(new_bh)) {
2031 			error = PTR_ERR(new_bh);
2032 			new_bh = NULL;
2033 			goto cleanup;
2034 		}
2035 
2036 		if (new_bh) {
2037 			/* We found an identical block in the cache. */
2038 			if (new_bh == bs->bh)
2039 				ea_bdebug(new_bh, "keeping");
2040 			else {
2041 				u32 ref;
2042 
2043 #ifdef EXT4_XATTR_DEBUG
2044 				WARN_ON_ONCE(dquot_initialize_needed(inode));
2045 #endif
2046 				/* The old block is released after updating
2047 				   the inode. */
2048 				error = dquot_alloc_block(inode,
2049 						EXT4_C2B(EXT4_SB(sb), 1));
2050 				if (error)
2051 					goto cleanup;
2052 				BUFFER_TRACE(new_bh, "get_write_access");
2053 				error = ext4_journal_get_write_access(
2054 						handle, sb, new_bh,
2055 						EXT4_JTR_NONE);
2056 				if (error)
2057 					goto cleanup_dquot;
2058 				lock_buffer(new_bh);
2059 				/*
2060 				 * We have to be careful about races with
2061 				 * adding references to xattr block. Once we
2062 				 * hold buffer lock xattr block's state is
2063 				 * stable so we can check the additional
2064 				 * reference fits.
2065 				 */
2066 				ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2067 				if (ref > EXT4_XATTR_REFCOUNT_MAX) {
2068 					/*
2069 					 * Undo everything and check mbcache
2070 					 * again.
2071 					 */
2072 					unlock_buffer(new_bh);
2073 					dquot_free_block(inode,
2074 							 EXT4_C2B(EXT4_SB(sb),
2075 								  1));
2076 					brelse(new_bh);
2077 					mb_cache_entry_put(ea_block_cache, ce);
2078 					ce = NULL;
2079 					new_bh = NULL;
2080 					goto inserted;
2081 				}
2082 				BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2083 				if (ref == EXT4_XATTR_REFCOUNT_MAX)
2084 					clear_bit(MBE_REUSABLE_B, &ce->e_flags);
2085 				ea_bdebug(new_bh, "reusing; refcount now=%d",
2086 					  ref);
2087 				ext4_xattr_block_csum_set(inode, new_bh);
2088 				unlock_buffer(new_bh);
2089 				error = ext4_handle_dirty_metadata(handle,
2090 								   inode,
2091 								   new_bh);
2092 				if (error)
2093 					goto cleanup_dquot;
2094 			}
2095 			mb_cache_entry_touch(ea_block_cache, ce);
2096 			mb_cache_entry_put(ea_block_cache, ce);
2097 			ce = NULL;
2098 		} else if (bs->bh && s->base == bs->bh->b_data) {
2099 			/* We were modifying this block in-place. */
2100 			ea_bdebug(bs->bh, "keeping this block");
2101 			ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2102 			new_bh = bs->bh;
2103 			get_bh(new_bh);
2104 		} else {
2105 			/* We need to allocate a new block */
2106 			ext4_fsblk_t goal, block;
2107 
2108 #ifdef EXT4_XATTR_DEBUG
2109 			WARN_ON_ONCE(dquot_initialize_needed(inode));
2110 #endif
2111 			goal = ext4_group_first_block_no(sb,
2112 						EXT4_I(inode)->i_block_group);
2113 			block = ext4_new_meta_blocks(handle, inode, goal, 0,
2114 						     NULL, &error);
2115 			if (error)
2116 				goto cleanup;
2117 
2118 			ea_idebug(inode, "creating block %llu",
2119 				  (unsigned long long)block);
2120 
2121 			new_bh = sb_getblk(sb, block);
2122 			if (unlikely(!new_bh)) {
2123 				error = -ENOMEM;
2124 getblk_failed:
2125 				ext4_free_blocks(handle, inode, NULL, block, 1,
2126 						 EXT4_FREE_BLOCKS_METADATA);
2127 				goto cleanup;
2128 			}
2129 			error = ext4_xattr_inode_inc_ref_all(handle, inode,
2130 						      ENTRY(header(s->base)+1));
2131 			if (error)
2132 				goto getblk_failed;
2133 			if (ea_inode) {
2134 				/* Drop the extra ref on ea_inode. */
2135 				error = ext4_xattr_inode_dec_ref(handle,
2136 								 ea_inode);
2137 				if (error)
2138 					ext4_warning_inode(ea_inode,
2139 							   "dec ref error=%d",
2140 							   error);
2141 				iput(ea_inode);
2142 				ea_inode = NULL;
2143 			}
2144 
2145 			lock_buffer(new_bh);
2146 			error = ext4_journal_get_create_access(handle, sb,
2147 							new_bh, EXT4_JTR_NONE);
2148 			if (error) {
2149 				unlock_buffer(new_bh);
2150 				error = -EIO;
2151 				goto getblk_failed;
2152 			}
2153 			memcpy(new_bh->b_data, s->base, new_bh->b_size);
2154 			ext4_xattr_block_csum_set(inode, new_bh);
2155 			set_buffer_uptodate(new_bh);
2156 			unlock_buffer(new_bh);
2157 			ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2158 			error = ext4_handle_dirty_metadata(handle, inode,
2159 							   new_bh);
2160 			if (error)
2161 				goto cleanup;
2162 		}
2163 	}
2164 
2165 	if (old_ea_inode_quota)
2166 		ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2167 
2168 	/* Update the inode. */
2169 	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2170 
2171 	/* Drop the previous xattr block. */
2172 	if (bs->bh && bs->bh != new_bh) {
2173 		struct ext4_xattr_inode_array *ea_inode_array = NULL;
2174 
2175 		ext4_xattr_release_block(handle, inode, bs->bh,
2176 					 &ea_inode_array,
2177 					 0 /* extra_credits */);
2178 		ext4_xattr_inode_array_free(ea_inode_array);
2179 	}
2180 	error = 0;
2181 
2182 cleanup:
2183 	if (ea_inode) {
2184 		if (error) {
2185 			int error2;
2186 
2187 			error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2188 			if (error2)
2189 				ext4_warning_inode(ea_inode, "dec ref error=%d",
2190 						   error2);
2191 			ext4_xattr_inode_free_quota(inode, ea_inode,
2192 						    i_size_read(ea_inode));
2193 		}
2194 		iput(ea_inode);
2195 	}
2196 	if (ce)
2197 		mb_cache_entry_put(ea_block_cache, ce);
2198 	brelse(new_bh);
2199 	if (!(bs->bh && s->base == bs->bh->b_data))
2200 		kfree(s->base);
2201 
2202 	return error;
2203 
2204 cleanup_dquot:
2205 	dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2206 	goto cleanup;
2207 
2208 bad_block:
2209 	EXT4_ERROR_INODE(inode, "bad block %llu",
2210 			 EXT4_I(inode)->i_file_acl);
2211 	goto cleanup;
2212 
2213 #undef header
2214 }
2215 
ext4_xattr_ibody_find(struct inode * inode,struct ext4_xattr_info * i,struct ext4_xattr_ibody_find * is)2216 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2217 			  struct ext4_xattr_ibody_find *is)
2218 {
2219 	struct ext4_xattr_ibody_header *header;
2220 	struct ext4_inode *raw_inode;
2221 	int error;
2222 
2223 	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2224 		return 0;
2225 
2226 	raw_inode = ext4_raw_inode(&is->iloc);
2227 	header = IHDR(inode, raw_inode);
2228 	is->s.base = is->s.first = IFIRST(header);
2229 	is->s.here = is->s.first;
2230 	is->s.end = ITAIL(inode, raw_inode);
2231 	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2232 		/* Find the named attribute. */
2233 		error = xattr_find_entry(inode, &is->s.here, is->s.end,
2234 					 i->name_index, i->name, 0);
2235 		if (error && error != -ENODATA)
2236 			return error;
2237 		is->s.not_found = error;
2238 	}
2239 	return 0;
2240 }
2241 
ext4_xattr_ibody_set(handle_t * handle,struct inode * inode,struct ext4_xattr_info * i,struct ext4_xattr_ibody_find * is)2242 int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2243 				struct ext4_xattr_info *i,
2244 				struct ext4_xattr_ibody_find *is)
2245 {
2246 	struct ext4_xattr_ibody_header *header;
2247 	struct ext4_xattr_search *s = &is->s;
2248 	struct inode *ea_inode = NULL;
2249 	int error;
2250 
2251 	if (!EXT4_INODE_HAS_XATTR_SPACE(inode))
2252 		return -ENOSPC;
2253 
2254 	/* If we need EA inode, prepare it before locking the buffer */
2255 	if (i->value && i->in_inode) {
2256 		WARN_ON_ONCE(!i->value_len);
2257 
2258 		ea_inode = ext4_xattr_inode_lookup_create(handle, inode,
2259 					i->value, i->value_len);
2260 		if (IS_ERR(ea_inode))
2261 			return PTR_ERR(ea_inode);
2262 	}
2263 	error = ext4_xattr_set_entry(i, s, handle, inode, ea_inode,
2264 				     false /* is_block */);
2265 	if (error) {
2266 		if (ea_inode) {
2267 			int error2;
2268 
2269 			error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2270 			if (error2)
2271 				ext4_warning_inode(ea_inode, "dec ref error=%d",
2272 						   error2);
2273 
2274 			ext4_xattr_inode_free_quota(inode, ea_inode,
2275 						    i_size_read(ea_inode));
2276 			iput(ea_inode);
2277 		}
2278 		return error;
2279 	}
2280 	header = IHDR(inode, ext4_raw_inode(&is->iloc));
2281 	if (!IS_LAST_ENTRY(s->first)) {
2282 		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2283 		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2284 	} else {
2285 		header->h_magic = cpu_to_le32(0);
2286 		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2287 	}
2288 	iput(ea_inode);
2289 	return 0;
2290 }
2291 
ext4_xattr_value_same(struct ext4_xattr_search * s,struct ext4_xattr_info * i)2292 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2293 				 struct ext4_xattr_info *i)
2294 {
2295 	void *value;
2296 
2297 	/* When e_value_inum is set the value is stored externally. */
2298 	if (s->here->e_value_inum)
2299 		return 0;
2300 	if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2301 		return 0;
2302 	value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2303 	return !memcmp(value, i->value, i->value_len);
2304 }
2305 
ext4_xattr_get_block(struct inode * inode)2306 static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2307 {
2308 	struct buffer_head *bh;
2309 	int error;
2310 
2311 	if (!EXT4_I(inode)->i_file_acl)
2312 		return NULL;
2313 	bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2314 	if (IS_ERR(bh))
2315 		return bh;
2316 	error = ext4_xattr_check_block(inode, bh);
2317 	if (error) {
2318 		brelse(bh);
2319 		return ERR_PTR(error);
2320 	}
2321 	return bh;
2322 }
2323 
2324 /*
2325  * ext4_xattr_set_handle()
2326  *
2327  * Create, replace or remove an extended attribute for this inode.  Value
2328  * is NULL to remove an existing extended attribute, and non-NULL to
2329  * either replace an existing extended attribute, or create a new extended
2330  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2331  * specify that an extended attribute must exist and must not exist
2332  * previous to the call, respectively.
2333  *
2334  * Returns 0, or a negative error number on failure.
2335  */
2336 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)2337 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2338 		      const char *name, const void *value, size_t value_len,
2339 		      int flags)
2340 {
2341 	struct ext4_xattr_info i = {
2342 		.name_index = name_index,
2343 		.name = name,
2344 		.value = value,
2345 		.value_len = value_len,
2346 		.in_inode = 0,
2347 	};
2348 	struct ext4_xattr_ibody_find is = {
2349 		.s = { .not_found = -ENODATA, },
2350 	};
2351 	struct ext4_xattr_block_find bs = {
2352 		.s = { .not_found = -ENODATA, },
2353 	};
2354 	int no_expand;
2355 	int error;
2356 
2357 	if (!name)
2358 		return -EINVAL;
2359 	if (strlen(name) > 255)
2360 		return -ERANGE;
2361 
2362 	ext4_write_lock_xattr(inode, &no_expand);
2363 
2364 	/* Check journal credits under write lock. */
2365 	if (ext4_handle_valid(handle)) {
2366 		struct buffer_head *bh;
2367 		int credits;
2368 
2369 		bh = ext4_xattr_get_block(inode);
2370 		if (IS_ERR(bh)) {
2371 			error = PTR_ERR(bh);
2372 			goto cleanup;
2373 		}
2374 
2375 		credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2376 						   value_len,
2377 						   flags & XATTR_CREATE);
2378 		brelse(bh);
2379 
2380 		if (jbd2_handle_buffer_credits(handle) < credits) {
2381 			error = -ENOSPC;
2382 			goto cleanup;
2383 		}
2384 		WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2385 	}
2386 
2387 	error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2388 	if (error)
2389 		goto cleanup;
2390 
2391 	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2392 		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2393 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2394 		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2395 	}
2396 
2397 	error = ext4_xattr_ibody_find(inode, &i, &is);
2398 	if (error)
2399 		goto cleanup;
2400 	if (is.s.not_found)
2401 		error = ext4_xattr_block_find(inode, &i, &bs);
2402 	if (error)
2403 		goto cleanup;
2404 	if (is.s.not_found && bs.s.not_found) {
2405 		error = -ENODATA;
2406 		if (flags & XATTR_REPLACE)
2407 			goto cleanup;
2408 		error = 0;
2409 		if (!value)
2410 			goto cleanup;
2411 	} else {
2412 		error = -EEXIST;
2413 		if (flags & XATTR_CREATE)
2414 			goto cleanup;
2415 	}
2416 
2417 	if (!value) {
2418 		if (!is.s.not_found)
2419 			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2420 		else if (!bs.s.not_found)
2421 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2422 	} else {
2423 		error = 0;
2424 		/* Xattr value did not change? Save us some work and bail out */
2425 		if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2426 			goto cleanup;
2427 		if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2428 			goto cleanup;
2429 
2430 		if (ext4_has_feature_ea_inode(inode->i_sb) &&
2431 		    (EXT4_XATTR_SIZE(i.value_len) >
2432 			EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2433 			i.in_inode = 1;
2434 retry_inode:
2435 		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2436 		if (!error && !bs.s.not_found) {
2437 			i.value = NULL;
2438 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2439 		} else if (error == -ENOSPC) {
2440 			if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2441 				brelse(bs.bh);
2442 				bs.bh = NULL;
2443 				error = ext4_xattr_block_find(inode, &i, &bs);
2444 				if (error)
2445 					goto cleanup;
2446 			}
2447 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
2448 			if (!error && !is.s.not_found) {
2449 				i.value = NULL;
2450 				error = ext4_xattr_ibody_set(handle, inode, &i,
2451 							     &is);
2452 			} else if (error == -ENOSPC) {
2453 				/*
2454 				 * Xattr does not fit in the block, store at
2455 				 * external inode if possible.
2456 				 */
2457 				if (ext4_has_feature_ea_inode(inode->i_sb) &&
2458 				    i.value_len && !i.in_inode) {
2459 					i.in_inode = 1;
2460 					goto retry_inode;
2461 				}
2462 			}
2463 		}
2464 	}
2465 	if (!error) {
2466 		ext4_xattr_update_super_block(handle, inode->i_sb);
2467 		inode_set_ctime_current(inode);
2468 		inode_inc_iversion(inode);
2469 		if (!value)
2470 			no_expand = 0;
2471 		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2472 		/*
2473 		 * The bh is consumed by ext4_mark_iloc_dirty, even with
2474 		 * error != 0.
2475 		 */
2476 		is.iloc.bh = NULL;
2477 		if (IS_SYNC(inode))
2478 			ext4_handle_sync(handle);
2479 	}
2480 	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2481 
2482 cleanup:
2483 	brelse(is.iloc.bh);
2484 	brelse(bs.bh);
2485 	ext4_write_unlock_xattr(inode, &no_expand);
2486 	return error;
2487 }
2488 
ext4_xattr_set_credits(struct inode * inode,size_t value_len,bool is_create,int * credits)2489 int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2490 			   bool is_create, int *credits)
2491 {
2492 	struct buffer_head *bh;
2493 	int err;
2494 
2495 	*credits = 0;
2496 
2497 	if (!EXT4_SB(inode->i_sb)->s_journal)
2498 		return 0;
2499 
2500 	down_read(&EXT4_I(inode)->xattr_sem);
2501 
2502 	bh = ext4_xattr_get_block(inode);
2503 	if (IS_ERR(bh)) {
2504 		err = PTR_ERR(bh);
2505 	} else {
2506 		*credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2507 						    value_len, is_create);
2508 		brelse(bh);
2509 		err = 0;
2510 	}
2511 
2512 	up_read(&EXT4_I(inode)->xattr_sem);
2513 	return err;
2514 }
2515 
2516 /*
2517  * ext4_xattr_set()
2518  *
2519  * Like ext4_xattr_set_handle, but start from an inode. This extended
2520  * attribute modification is a filesystem transaction by itself.
2521  *
2522  * Returns 0, or a negative error number on failure.
2523  */
2524 int
ext4_xattr_set(struct inode * inode,int name_index,const char * name,const void * value,size_t value_len,int flags)2525 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2526 	       const void *value, size_t value_len, int flags)
2527 {
2528 	handle_t *handle;
2529 	struct super_block *sb = inode->i_sb;
2530 	int error, retries = 0;
2531 	int credits;
2532 
2533 	error = dquot_initialize(inode);
2534 	if (error)
2535 		return error;
2536 
2537 retry:
2538 	error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2539 				       &credits);
2540 	if (error)
2541 		return error;
2542 
2543 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2544 	if (IS_ERR(handle)) {
2545 		error = PTR_ERR(handle);
2546 	} else {
2547 		int error2;
2548 
2549 		error = ext4_xattr_set_handle(handle, inode, name_index, name,
2550 					      value, value_len, flags);
2551 		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR,
2552 					handle);
2553 		error2 = ext4_journal_stop(handle);
2554 		if (error == -ENOSPC &&
2555 		    ext4_should_retry_alloc(sb, &retries))
2556 			goto retry;
2557 		if (error == 0)
2558 			error = error2;
2559 	}
2560 
2561 	return error;
2562 }
2563 
2564 /*
2565  * Shift the EA entries in the inode to create space for the increased
2566  * i_extra_isize.
2567  */
ext4_xattr_shift_entries(struct ext4_xattr_entry * entry,int value_offs_shift,void * to,void * from,size_t n)2568 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2569 				     int value_offs_shift, void *to,
2570 				     void *from, size_t n)
2571 {
2572 	struct ext4_xattr_entry *last = entry;
2573 	int new_offs;
2574 
2575 	/* We always shift xattr headers further thus offsets get lower */
2576 	BUG_ON(value_offs_shift > 0);
2577 
2578 	/* Adjust the value offsets of the entries */
2579 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2580 		if (!last->e_value_inum && last->e_value_size) {
2581 			new_offs = le16_to_cpu(last->e_value_offs) +
2582 							value_offs_shift;
2583 			last->e_value_offs = cpu_to_le16(new_offs);
2584 		}
2585 	}
2586 	/* Shift the entries by n bytes */
2587 	memmove(to, from, n);
2588 }
2589 
2590 /*
2591  * Move xattr pointed to by 'entry' from inode into external xattr block
2592  */
ext4_xattr_move_to_block(handle_t * handle,struct inode * inode,struct ext4_inode * raw_inode,struct ext4_xattr_entry * entry)2593 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2594 				    struct ext4_inode *raw_inode,
2595 				    struct ext4_xattr_entry *entry)
2596 {
2597 	struct ext4_xattr_ibody_find *is = NULL;
2598 	struct ext4_xattr_block_find *bs = NULL;
2599 	char *buffer = NULL, *b_entry_name = NULL;
2600 	size_t value_size = le32_to_cpu(entry->e_value_size);
2601 	struct ext4_xattr_info i = {
2602 		.value = NULL,
2603 		.value_len = 0,
2604 		.name_index = entry->e_name_index,
2605 		.in_inode = !!entry->e_value_inum,
2606 	};
2607 	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2608 	int needs_kvfree = 0;
2609 	int error;
2610 
2611 	is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2612 	bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2613 	b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2614 	if (!is || !bs || !b_entry_name) {
2615 		error = -ENOMEM;
2616 		goto out;
2617 	}
2618 
2619 	is->s.not_found = -ENODATA;
2620 	bs->s.not_found = -ENODATA;
2621 	is->iloc.bh = NULL;
2622 	bs->bh = NULL;
2623 
2624 	/* Save the entry name and the entry value */
2625 	if (entry->e_value_inum) {
2626 		buffer = kvmalloc(value_size, GFP_NOFS);
2627 		if (!buffer) {
2628 			error = -ENOMEM;
2629 			goto out;
2630 		}
2631 		needs_kvfree = 1;
2632 		error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2633 		if (error)
2634 			goto out;
2635 	} else {
2636 		size_t value_offs = le16_to_cpu(entry->e_value_offs);
2637 		buffer = (void *)IFIRST(header) + value_offs;
2638 	}
2639 
2640 	memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2641 	b_entry_name[entry->e_name_len] = '\0';
2642 	i.name = b_entry_name;
2643 
2644 	error = ext4_get_inode_loc(inode, &is->iloc);
2645 	if (error)
2646 		goto out;
2647 
2648 	error = ext4_xattr_ibody_find(inode, &i, is);
2649 	if (error)
2650 		goto out;
2651 
2652 	i.value = buffer;
2653 	i.value_len = value_size;
2654 	error = ext4_xattr_block_find(inode, &i, bs);
2655 	if (error)
2656 		goto out;
2657 
2658 	/* Move ea entry from the inode into the block */
2659 	error = ext4_xattr_block_set(handle, inode, &i, bs);
2660 	if (error)
2661 		goto out;
2662 
2663 	/* Remove the chosen entry from the inode */
2664 	i.value = NULL;
2665 	i.value_len = 0;
2666 	error = ext4_xattr_ibody_set(handle, inode, &i, is);
2667 
2668 out:
2669 	kfree(b_entry_name);
2670 	if (needs_kvfree && buffer)
2671 		kvfree(buffer);
2672 	if (is)
2673 		brelse(is->iloc.bh);
2674 	if (bs)
2675 		brelse(bs->bh);
2676 	kfree(is);
2677 	kfree(bs);
2678 
2679 	return error;
2680 }
2681 
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)2682 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2683 				       struct ext4_inode *raw_inode,
2684 				       int isize_diff, size_t ifree,
2685 				       size_t bfree, int *total_ino)
2686 {
2687 	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2688 	struct ext4_xattr_entry *small_entry;
2689 	struct ext4_xattr_entry *entry;
2690 	struct ext4_xattr_entry *last;
2691 	unsigned int entry_size;	/* EA entry size */
2692 	unsigned int total_size;	/* EA entry size + value size */
2693 	unsigned int min_total_size;
2694 	int error;
2695 
2696 	while (isize_diff > ifree) {
2697 		entry = NULL;
2698 		small_entry = NULL;
2699 		min_total_size = ~0U;
2700 		last = IFIRST(header);
2701 		/* Find the entry best suited to be pushed into EA block */
2702 		for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2703 			/* never move system.data out of the inode */
2704 			if ((last->e_name_len == 4) &&
2705 			    (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2706 			    !memcmp(last->e_name, "data", 4))
2707 				continue;
2708 			total_size = EXT4_XATTR_LEN(last->e_name_len);
2709 			if (!last->e_value_inum)
2710 				total_size += EXT4_XATTR_SIZE(
2711 					       le32_to_cpu(last->e_value_size));
2712 			if (total_size <= bfree &&
2713 			    total_size < min_total_size) {
2714 				if (total_size + ifree < isize_diff) {
2715 					small_entry = last;
2716 				} else {
2717 					entry = last;
2718 					min_total_size = total_size;
2719 				}
2720 			}
2721 		}
2722 
2723 		if (entry == NULL) {
2724 			if (small_entry == NULL)
2725 				return -ENOSPC;
2726 			entry = small_entry;
2727 		}
2728 
2729 		entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2730 		total_size = entry_size;
2731 		if (!entry->e_value_inum)
2732 			total_size += EXT4_XATTR_SIZE(
2733 					      le32_to_cpu(entry->e_value_size));
2734 		error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2735 						 entry);
2736 		if (error)
2737 			return error;
2738 
2739 		*total_ino -= entry_size;
2740 		ifree += total_size;
2741 		bfree -= total_size;
2742 	}
2743 
2744 	return 0;
2745 }
2746 
2747 /*
2748  * Expand an inode by new_extra_isize bytes when EAs are present.
2749  * Returns 0 on success or negative error number on failure.
2750  */
ext4_expand_extra_isize_ea(struct inode * inode,int new_extra_isize,struct ext4_inode * raw_inode,handle_t * handle)2751 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2752 			       struct ext4_inode *raw_inode, handle_t *handle)
2753 {
2754 	struct ext4_xattr_ibody_header *header;
2755 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2756 	static unsigned int mnt_count;
2757 	size_t min_offs;
2758 	size_t ifree, bfree;
2759 	int total_ino;
2760 	void *base, *end;
2761 	int error = 0, tried_min_extra_isize = 0;
2762 	int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2763 	int isize_diff;	/* How much do we need to grow i_extra_isize */
2764 
2765 retry:
2766 	isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2767 	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2768 		return 0;
2769 
2770 	header = IHDR(inode, raw_inode);
2771 
2772 	/*
2773 	 * Check if enough free space is available in the inode to shift the
2774 	 * entries ahead by new_extra_isize.
2775 	 */
2776 
2777 	base = IFIRST(header);
2778 	end = ITAIL(inode, raw_inode);
2779 	min_offs = end - base;
2780 	total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2781 
2782 	ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2783 	if (ifree >= isize_diff)
2784 		goto shift;
2785 
2786 	/*
2787 	 * Enough free space isn't available in the inode, check if
2788 	 * EA block can hold new_extra_isize bytes.
2789 	 */
2790 	if (EXT4_I(inode)->i_file_acl) {
2791 		struct buffer_head *bh;
2792 
2793 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2794 		if (IS_ERR(bh)) {
2795 			error = PTR_ERR(bh);
2796 			goto cleanup;
2797 		}
2798 		error = ext4_xattr_check_block(inode, bh);
2799 		if (error) {
2800 			brelse(bh);
2801 			goto cleanup;
2802 		}
2803 		base = BHDR(bh);
2804 		end = bh->b_data + bh->b_size;
2805 		min_offs = end - base;
2806 		bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2807 					      NULL);
2808 		brelse(bh);
2809 		if (bfree + ifree < isize_diff) {
2810 			if (!tried_min_extra_isize && s_min_extra_isize) {
2811 				tried_min_extra_isize++;
2812 				new_extra_isize = s_min_extra_isize;
2813 				goto retry;
2814 			}
2815 			error = -ENOSPC;
2816 			goto cleanup;
2817 		}
2818 	} else {
2819 		bfree = inode->i_sb->s_blocksize;
2820 	}
2821 
2822 	error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2823 					    isize_diff, ifree, bfree,
2824 					    &total_ino);
2825 	if (error) {
2826 		if (error == -ENOSPC && !tried_min_extra_isize &&
2827 		    s_min_extra_isize) {
2828 			tried_min_extra_isize++;
2829 			new_extra_isize = s_min_extra_isize;
2830 			goto retry;
2831 		}
2832 		goto cleanup;
2833 	}
2834 shift:
2835 	/* Adjust the offsets and shift the remaining entries ahead */
2836 	ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2837 			- new_extra_isize, (void *)raw_inode +
2838 			EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2839 			(void *)header, total_ino);
2840 	EXT4_I(inode)->i_extra_isize = new_extra_isize;
2841 
2842 	if (ext4_has_inline_data(inode))
2843 		error = ext4_find_inline_data_nolock(inode);
2844 
2845 cleanup:
2846 	if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2847 		ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2848 			     inode->i_ino);
2849 		mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2850 	}
2851 	return error;
2852 }
2853 
2854 #define EIA_INCR 16 /* must be 2^n */
2855 #define EIA_MASK (EIA_INCR - 1)
2856 
2857 /* Add the large xattr @inode into @ea_inode_array for deferred iput().
2858  * If @ea_inode_array is new or full it will be grown and the old
2859  * contents copied over.
2860  */
2861 static int
ext4_expand_inode_array(struct ext4_xattr_inode_array ** ea_inode_array,struct inode * inode)2862 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2863 			struct inode *inode)
2864 {
2865 	if (*ea_inode_array == NULL) {
2866 		/*
2867 		 * Start with 15 inodes, so it fits into a power-of-two size.
2868 		 */
2869 		(*ea_inode_array) = kmalloc(
2870 			struct_size(*ea_inode_array, inodes, EIA_MASK),
2871 			GFP_NOFS);
2872 		if (*ea_inode_array == NULL)
2873 			return -ENOMEM;
2874 		(*ea_inode_array)->count = 0;
2875 	} else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2876 		/* expand the array once all 15 + n * 16 slots are full */
2877 		struct ext4_xattr_inode_array *new_array = NULL;
2878 
2879 		new_array = kmalloc(
2880 			struct_size(*ea_inode_array, inodes,
2881 				    (*ea_inode_array)->count + EIA_INCR),
2882 			GFP_NOFS);
2883 		if (new_array == NULL)
2884 			return -ENOMEM;
2885 		memcpy(new_array, *ea_inode_array,
2886 		       struct_size(*ea_inode_array, inodes,
2887 				   (*ea_inode_array)->count));
2888 		kfree(*ea_inode_array);
2889 		*ea_inode_array = new_array;
2890 	}
2891 	(*ea_inode_array)->count++;
2892 	(*ea_inode_array)->inodes[(*ea_inode_array)->count - 1] = inode;
2893 	return 0;
2894 }
2895 
2896 /*
2897  * ext4_xattr_delete_inode()
2898  *
2899  * Free extended attribute resources associated with this inode. Traverse
2900  * all entries and decrement reference on any xattr inodes associated with this
2901  * inode. This is called immediately before an inode is freed. We have exclusive
2902  * access to the inode. If an orphan inode is deleted it will also release its
2903  * references on xattr block and xattr inodes.
2904  */
ext4_xattr_delete_inode(handle_t * handle,struct inode * inode,struct ext4_xattr_inode_array ** ea_inode_array,int extra_credits)2905 int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2906 			    struct ext4_xattr_inode_array **ea_inode_array,
2907 			    int extra_credits)
2908 {
2909 	struct buffer_head *bh = NULL;
2910 	struct ext4_xattr_ibody_header *header;
2911 	struct ext4_iloc iloc = { .bh = NULL };
2912 	struct ext4_xattr_entry *entry;
2913 	struct inode *ea_inode;
2914 	int error;
2915 
2916 	error = ext4_journal_ensure_credits(handle, extra_credits,
2917 			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2918 	if (error < 0) {
2919 		EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2920 		goto cleanup;
2921 	}
2922 
2923 	if (ext4_has_feature_ea_inode(inode->i_sb) &&
2924 	    ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2925 
2926 		error = ext4_get_inode_loc(inode, &iloc);
2927 		if (error) {
2928 			EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2929 			goto cleanup;
2930 		}
2931 
2932 		error = ext4_journal_get_write_access(handle, inode->i_sb,
2933 						iloc.bh, EXT4_JTR_NONE);
2934 		if (error) {
2935 			EXT4_ERROR_INODE(inode, "write access (error %d)",
2936 					 error);
2937 			goto cleanup;
2938 		}
2939 
2940 		header = IHDR(inode, ext4_raw_inode(&iloc));
2941 		if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2942 			ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2943 						     IFIRST(header),
2944 						     false /* block_csum */,
2945 						     ea_inode_array,
2946 						     extra_credits,
2947 						     false /* skip_quota */);
2948 	}
2949 
2950 	if (EXT4_I(inode)->i_file_acl) {
2951 		bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2952 		if (IS_ERR(bh)) {
2953 			error = PTR_ERR(bh);
2954 			if (error == -EIO) {
2955 				EXT4_ERROR_INODE_ERR(inode, EIO,
2956 						     "block %llu read error",
2957 						     EXT4_I(inode)->i_file_acl);
2958 			}
2959 			bh = NULL;
2960 			goto cleanup;
2961 		}
2962 		error = ext4_xattr_check_block(inode, bh);
2963 		if (error)
2964 			goto cleanup;
2965 
2966 		if (ext4_has_feature_ea_inode(inode->i_sb)) {
2967 			for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2968 			     entry = EXT4_XATTR_NEXT(entry)) {
2969 				if (!entry->e_value_inum)
2970 					continue;
2971 				error = ext4_xattr_inode_iget(inode,
2972 					      le32_to_cpu(entry->e_value_inum),
2973 					      le32_to_cpu(entry->e_hash),
2974 					      &ea_inode);
2975 				if (error)
2976 					continue;
2977 				ext4_xattr_inode_free_quota(inode, ea_inode,
2978 					      le32_to_cpu(entry->e_value_size));
2979 				iput(ea_inode);
2980 			}
2981 
2982 		}
2983 
2984 		ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2985 					 extra_credits);
2986 		/*
2987 		 * Update i_file_acl value in the same transaction that releases
2988 		 * block.
2989 		 */
2990 		EXT4_I(inode)->i_file_acl = 0;
2991 		error = ext4_mark_inode_dirty(handle, inode);
2992 		if (error) {
2993 			EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2994 					 error);
2995 			goto cleanup;
2996 		}
2997 		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle);
2998 	}
2999 	error = 0;
3000 cleanup:
3001 	brelse(iloc.bh);
3002 	brelse(bh);
3003 	return error;
3004 }
3005 
ext4_xattr_inode_array_free(struct ext4_xattr_inode_array * ea_inode_array)3006 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
3007 {
3008 	int idx;
3009 
3010 	if (ea_inode_array == NULL)
3011 		return;
3012 
3013 	for (idx = 0; idx < ea_inode_array->count; ++idx)
3014 		iput(ea_inode_array->inodes[idx]);
3015 	kfree(ea_inode_array);
3016 }
3017 
3018 /*
3019  * ext4_xattr_block_cache_insert()
3020  *
3021  * Create a new entry in the extended attribute block cache, and insert
3022  * it unless such an entry is already in the cache.
3023  */
3024 static void
ext4_xattr_block_cache_insert(struct mb_cache * ea_block_cache,struct buffer_head * bh)3025 ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
3026 			      struct buffer_head *bh)
3027 {
3028 	struct ext4_xattr_header *header = BHDR(bh);
3029 	__u32 hash = le32_to_cpu(header->h_hash);
3030 	int reusable = le32_to_cpu(header->h_refcount) <
3031 		       EXT4_XATTR_REFCOUNT_MAX;
3032 	int error;
3033 
3034 	if (!ea_block_cache)
3035 		return;
3036 	error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
3037 				      bh->b_blocknr, reusable);
3038 	if (error) {
3039 		if (error == -EBUSY)
3040 			ea_bdebug(bh, "already in cache");
3041 	} else
3042 		ea_bdebug(bh, "inserting [%x]", (int)hash);
3043 }
3044 
3045 /*
3046  * ext4_xattr_cmp()
3047  *
3048  * Compare two extended attribute blocks for equality.
3049  *
3050  * Returns 0 if the blocks are equal, 1 if they differ.
3051  */
3052 static int
ext4_xattr_cmp(struct ext4_xattr_header * header1,struct ext4_xattr_header * header2)3053 ext4_xattr_cmp(struct ext4_xattr_header *header1,
3054 	       struct ext4_xattr_header *header2)
3055 {
3056 	struct ext4_xattr_entry *entry1, *entry2;
3057 
3058 	entry1 = ENTRY(header1+1);
3059 	entry2 = ENTRY(header2+1);
3060 	while (!IS_LAST_ENTRY(entry1)) {
3061 		if (IS_LAST_ENTRY(entry2))
3062 			return 1;
3063 		if (entry1->e_hash != entry2->e_hash ||
3064 		    entry1->e_name_index != entry2->e_name_index ||
3065 		    entry1->e_name_len != entry2->e_name_len ||
3066 		    entry1->e_value_size != entry2->e_value_size ||
3067 		    entry1->e_value_inum != entry2->e_value_inum ||
3068 		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
3069 			return 1;
3070 		if (!entry1->e_value_inum &&
3071 		    memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
3072 			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
3073 			   le32_to_cpu(entry1->e_value_size)))
3074 			return 1;
3075 
3076 		entry1 = EXT4_XATTR_NEXT(entry1);
3077 		entry2 = EXT4_XATTR_NEXT(entry2);
3078 	}
3079 	if (!IS_LAST_ENTRY(entry2))
3080 		return 1;
3081 	return 0;
3082 }
3083 
3084 /*
3085  * ext4_xattr_block_cache_find()
3086  *
3087  * Find an identical extended attribute block.
3088  *
3089  * Returns a pointer to the block found, or NULL if such a block was not
3090  * found, or an error pointer if an error occurred while reading ea block.
3091  */
3092 static struct buffer_head *
ext4_xattr_block_cache_find(struct inode * inode,struct ext4_xattr_header * header,struct mb_cache_entry ** pce)3093 ext4_xattr_block_cache_find(struct inode *inode,
3094 			    struct ext4_xattr_header *header,
3095 			    struct mb_cache_entry **pce)
3096 {
3097 	__u32 hash = le32_to_cpu(header->h_hash);
3098 	struct mb_cache_entry *ce;
3099 	struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3100 
3101 	if (!ea_block_cache)
3102 		return NULL;
3103 	if (!header->h_hash)
3104 		return NULL;  /* never share */
3105 	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3106 	ce = mb_cache_entry_find_first(ea_block_cache, hash);
3107 	while (ce) {
3108 		struct buffer_head *bh;
3109 
3110 		bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3111 		if (IS_ERR(bh)) {
3112 			if (PTR_ERR(bh) != -ENOMEM)
3113 				EXT4_ERROR_INODE(inode, "block %lu read error",
3114 						 (unsigned long)ce->e_value);
3115 			mb_cache_entry_put(ea_block_cache, ce);
3116 			return bh;
3117 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3118 			*pce = ce;
3119 			return bh;
3120 		}
3121 		brelse(bh);
3122 		ce = mb_cache_entry_find_next(ea_block_cache, ce);
3123 	}
3124 	return NULL;
3125 }
3126 
3127 #define NAME_HASH_SHIFT 5
3128 #define VALUE_HASH_SHIFT 16
3129 
3130 /*
3131  * ext4_xattr_hash_entry()
3132  *
3133  * Compute the hash of an extended attribute.
3134  */
ext4_xattr_hash_entry(char * name,size_t name_len,__le32 * value,size_t value_count)3135 static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3136 				    size_t value_count)
3137 {
3138 	__u32 hash = 0;
3139 
3140 	while (name_len--) {
3141 		hash = (hash << NAME_HASH_SHIFT) ^
3142 		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3143 		       (unsigned char)*name++;
3144 	}
3145 	while (value_count--) {
3146 		hash = (hash << VALUE_HASH_SHIFT) ^
3147 		       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3148 		       le32_to_cpu(*value++);
3149 	}
3150 	return cpu_to_le32(hash);
3151 }
3152 
3153 /*
3154  * ext4_xattr_hash_entry_signed()
3155  *
3156  * Compute the hash of an extended attribute incorrectly.
3157  */
ext4_xattr_hash_entry_signed(char * name,size_t name_len,__le32 * value,size_t value_count)3158 static __le32 ext4_xattr_hash_entry_signed(char *name, size_t name_len, __le32 *value, size_t value_count)
3159 {
3160 	__u32 hash = 0;
3161 
3162 	while (name_len--) {
3163 		hash = (hash << NAME_HASH_SHIFT) ^
3164 		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3165 		       (signed char)*name++;
3166 	}
3167 	while (value_count--) {
3168 		hash = (hash << VALUE_HASH_SHIFT) ^
3169 		       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3170 		       le32_to_cpu(*value++);
3171 	}
3172 	return cpu_to_le32(hash);
3173 }
3174 
3175 #undef NAME_HASH_SHIFT
3176 #undef VALUE_HASH_SHIFT
3177 
3178 #define BLOCK_HASH_SHIFT 16
3179 
3180 /*
3181  * ext4_xattr_rehash()
3182  *
3183  * Re-compute the extended attribute hash value after an entry has changed.
3184  */
ext4_xattr_rehash(struct ext4_xattr_header * header)3185 static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3186 {
3187 	struct ext4_xattr_entry *here;
3188 	__u32 hash = 0;
3189 
3190 	here = ENTRY(header+1);
3191 	while (!IS_LAST_ENTRY(here)) {
3192 		if (!here->e_hash) {
3193 			/* Block is not shared if an entry's hash value == 0 */
3194 			hash = 0;
3195 			break;
3196 		}
3197 		hash = (hash << BLOCK_HASH_SHIFT) ^
3198 		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3199 		       le32_to_cpu(here->e_hash);
3200 		here = EXT4_XATTR_NEXT(here);
3201 	}
3202 	header->h_hash = cpu_to_le32(hash);
3203 }
3204 
3205 #undef BLOCK_HASH_SHIFT
3206 
3207 #define	HASH_BUCKET_BITS	10
3208 
3209 struct mb_cache *
ext4_xattr_create_cache(void)3210 ext4_xattr_create_cache(void)
3211 {
3212 	return mb_cache_create(HASH_BUCKET_BITS);
3213 }
3214 
ext4_xattr_destroy_cache(struct mb_cache * cache)3215 void ext4_xattr_destroy_cache(struct mb_cache *cache)
3216 {
3217 	if (cache)
3218 		mb_cache_destroy(cache);
3219 }
3220 
3221