Merge branch 'linus' into x86/tracehook
[linux-2.6] / fs / ext4 / xattr.c
1 /*
2  * linux/fs/ext4/xattr.c
3  *
4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5  *
6  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7  * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8  * Extended attributes for symlinks and special files added per
9  *  suggestion of Luka Renko <luka.renko@hermes.si>.
10  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11  *  Red Hat Inc.
12  * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13  *  and Andreas Gruenbacher <agruen@suse.de>.
14  */
15
16 /*
17  * Extended attributes are stored directly in inodes (on file systems with
18  * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19  * field contains the block number if an inode uses an additional block. All
20  * attributes must fit in the inode and one additional block. Blocks that
21  * contain the identical set of attributes may be shared among several inodes.
22  * Identical blocks are detected by keeping a cache of blocks that have
23  * recently been accessed.
24  *
25  * The attributes in inodes and on blocks have a different header; the entries
26  * are stored in the same format:
27  *
28  *   +------------------+
29  *   | header           |
30  *   | entry 1          | |
31  *   | entry 2          | | growing downwards
32  *   | entry 3          | v
33  *   | four null bytes  |
34  *   | . . .            |
35  *   | value 1          | ^
36  *   | value 3          | | growing upwards
37  *   | value 2          | |
38  *   +------------------+
39  *
40  * The header is followed by multiple entry descriptors. In disk blocks, the
41  * entry descriptors are kept sorted. In inodes, they are unsorted. The
42  * attribute values are aligned to the end of the block in no specific order.
43  *
44  * Locking strategy
45  * ----------------
46  * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47  * EA blocks are only changed if they are exclusive to an inode, so
48  * holding xattr_sem also means that nothing but the EA block's reference
49  * count can change. Multiple writers to the same block are synchronized
50  * by the buffer lock.
51  */
52
53 #include <linux/init.h>
54 #include <linux/fs.h>
55 #include <linux/slab.h>
56 #include <linux/mbcache.h>
57 #include <linux/quotaops.h>
58 #include <linux/rwsem.h>
59 #include "ext4_jbd2.h"
60 #include "ext4.h"
61 #include "xattr.h"
62 #include "acl.h"
63
64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
68
69 #ifdef EXT4_XATTR_DEBUG
70 # define ea_idebug(inode, f...) do { \
71                 printk(KERN_DEBUG "inode %s:%lu: ", \
72                         inode->i_sb->s_id, inode->i_ino); \
73                 printk(f); \
74                 printk("\n"); \
75         } while (0)
76 # define ea_bdebug(bh, f...) do { \
77                 char b[BDEVNAME_SIZE]; \
78                 printk(KERN_DEBUG "block %s:%lu: ", \
79                         bdevname(bh->b_bdev, b), \
80                         (unsigned long) bh->b_blocknr); \
81                 printk(f); \
82                 printk("\n"); \
83         } while (0)
84 #else
85 # define ea_idebug(f...)
86 # define ea_bdebug(f...)
87 #endif
88
89 static void ext4_xattr_cache_insert(struct buffer_head *);
90 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
91                                                  struct ext4_xattr_header *,
92                                                  struct mb_cache_entry **);
93 static void ext4_xattr_rehash(struct ext4_xattr_header *,
94                               struct ext4_xattr_entry *);
95 static int ext4_xattr_list(struct inode *inode, char *buffer,
96                            size_t buffer_size);
97
98 static struct mb_cache *ext4_xattr_cache;
99
100 static struct xattr_handler *ext4_xattr_handler_map[] = {
101         [EXT4_XATTR_INDEX_USER]              = &ext4_xattr_user_handler,
102 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
103         [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext4_xattr_acl_access_handler,
104         [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
105 #endif
106         [EXT4_XATTR_INDEX_TRUSTED]           = &ext4_xattr_trusted_handler,
107 #ifdef CONFIG_EXT4DEV_FS_SECURITY
108         [EXT4_XATTR_INDEX_SECURITY]          = &ext4_xattr_security_handler,
109 #endif
110 };
111
112 struct xattr_handler *ext4_xattr_handlers[] = {
113         &ext4_xattr_user_handler,
114         &ext4_xattr_trusted_handler,
115 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
116         &ext4_xattr_acl_access_handler,
117         &ext4_xattr_acl_default_handler,
118 #endif
119 #ifdef CONFIG_EXT4DEV_FS_SECURITY
120         &ext4_xattr_security_handler,
121 #endif
122         NULL
123 };
124
125 static inline struct xattr_handler *
126 ext4_xattr_handler(int name_index)
127 {
128         struct xattr_handler *handler = NULL;
129
130         if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
131                 handler = ext4_xattr_handler_map[name_index];
132         return handler;
133 }
134
135 /*
136  * Inode operation listxattr()
137  *
138  * dentry->d_inode->i_mutex: don't care
139  */
140 ssize_t
141 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
142 {
143         return ext4_xattr_list(dentry->d_inode, buffer, size);
144 }
145
146 static int
147 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
148 {
149         while (!IS_LAST_ENTRY(entry)) {
150                 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
151                 if ((void *)next >= end)
152                         return -EIO;
153                 entry = next;
154         }
155         return 0;
156 }
157
158 static inline int
159 ext4_xattr_check_block(struct buffer_head *bh)
160 {
161         int error;
162
163         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
164             BHDR(bh)->h_blocks != cpu_to_le32(1))
165                 return -EIO;
166         error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
167         return error;
168 }
169
170 static inline int
171 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
172 {
173         size_t value_size = le32_to_cpu(entry->e_value_size);
174
175         if (entry->e_value_block != 0 || value_size > size ||
176             le16_to_cpu(entry->e_value_offs) + value_size > size)
177                 return -EIO;
178         return 0;
179 }
180
181 static int
182 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
183                       const char *name, size_t size, int sorted)
184 {
185         struct ext4_xattr_entry *entry;
186         size_t name_len;
187         int cmp = 1;
188
189         if (name == NULL)
190                 return -EINVAL;
191         name_len = strlen(name);
192         entry = *pentry;
193         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
194                 cmp = name_index - entry->e_name_index;
195                 if (!cmp)
196                         cmp = name_len - entry->e_name_len;
197                 if (!cmp)
198                         cmp = memcmp(name, entry->e_name, name_len);
199                 if (cmp <= 0 && (sorted || cmp == 0))
200                         break;
201         }
202         *pentry = entry;
203         if (!cmp && ext4_xattr_check_entry(entry, size))
204                         return -EIO;
205         return cmp ? -ENODATA : 0;
206 }
207
208 static int
209 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
210                      void *buffer, size_t buffer_size)
211 {
212         struct buffer_head *bh = NULL;
213         struct ext4_xattr_entry *entry;
214         size_t size;
215         int error;
216
217         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
218                   name_index, name, buffer, (long)buffer_size);
219
220         error = -ENODATA;
221         if (!EXT4_I(inode)->i_file_acl)
222                 goto cleanup;
223         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
224         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
225         if (!bh)
226                 goto cleanup;
227         ea_bdebug(bh, "b_count=%d, refcount=%d",
228                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
229         if (ext4_xattr_check_block(bh)) {
230 bad_block:      ext4_error(inode->i_sb, __func__,
231                            "inode %lu: bad block %llu", inode->i_ino,
232                            EXT4_I(inode)->i_file_acl);
233                 error = -EIO;
234                 goto cleanup;
235         }
236         ext4_xattr_cache_insert(bh);
237         entry = BFIRST(bh);
238         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
239         if (error == -EIO)
240                 goto bad_block;
241         if (error)
242                 goto cleanup;
243         size = le32_to_cpu(entry->e_value_size);
244         if (buffer) {
245                 error = -ERANGE;
246                 if (size > buffer_size)
247                         goto cleanup;
248                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
249                        size);
250         }
251         error = size;
252
253 cleanup:
254         brelse(bh);
255         return error;
256 }
257
258 static int
259 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
260                      void *buffer, size_t buffer_size)
261 {
262         struct ext4_xattr_ibody_header *header;
263         struct ext4_xattr_entry *entry;
264         struct ext4_inode *raw_inode;
265         struct ext4_iloc iloc;
266         size_t size;
267         void *end;
268         int error;
269
270         if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
271                 return -ENODATA;
272         error = ext4_get_inode_loc(inode, &iloc);
273         if (error)
274                 return error;
275         raw_inode = ext4_raw_inode(&iloc);
276         header = IHDR(inode, raw_inode);
277         entry = IFIRST(header);
278         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
279         error = ext4_xattr_check_names(entry, end);
280         if (error)
281                 goto cleanup;
282         error = ext4_xattr_find_entry(&entry, name_index, name,
283                                       end - (void *)entry, 0);
284         if (error)
285                 goto cleanup;
286         size = le32_to_cpu(entry->e_value_size);
287         if (buffer) {
288                 error = -ERANGE;
289                 if (size > buffer_size)
290                         goto cleanup;
291                 memcpy(buffer, (void *)IFIRST(header) +
292                        le16_to_cpu(entry->e_value_offs), size);
293         }
294         error = size;
295
296 cleanup:
297         brelse(iloc.bh);
298         return error;
299 }
300
301 /*
302  * ext4_xattr_get()
303  *
304  * Copy an extended attribute into the buffer
305  * provided, or compute the buffer size required.
306  * Buffer is NULL to compute the size of the buffer required.
307  *
308  * Returns a negative error number on failure, or the number of bytes
309  * used / required on success.
310  */
311 int
312 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
313                void *buffer, size_t buffer_size)
314 {
315         int error;
316
317         down_read(&EXT4_I(inode)->xattr_sem);
318         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
319                                      buffer_size);
320         if (error == -ENODATA)
321                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
322                                              buffer_size);
323         up_read(&EXT4_I(inode)->xattr_sem);
324         return error;
325 }
326
327 static int
328 ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry,
329                         char *buffer, size_t buffer_size)
330 {
331         size_t rest = buffer_size;
332
333         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
334                 struct xattr_handler *handler =
335                         ext4_xattr_handler(entry->e_name_index);
336
337                 if (handler) {
338                         size_t size = handler->list(inode, buffer, rest,
339                                                     entry->e_name,
340                                                     entry->e_name_len);
341                         if (buffer) {
342                                 if (size > rest)
343                                         return -ERANGE;
344                                 buffer += size;
345                         }
346                         rest -= size;
347                 }
348         }
349         return buffer_size - rest;
350 }
351
352 static int
353 ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
354 {
355         struct buffer_head *bh = NULL;
356         int error;
357
358         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
359                   buffer, (long)buffer_size);
360
361         error = 0;
362         if (!EXT4_I(inode)->i_file_acl)
363                 goto cleanup;
364         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
365         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
366         error = -EIO;
367         if (!bh)
368                 goto cleanup;
369         ea_bdebug(bh, "b_count=%d, refcount=%d",
370                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
371         if (ext4_xattr_check_block(bh)) {
372                 ext4_error(inode->i_sb, __func__,
373                            "inode %lu: bad block %llu", inode->i_ino,
374                            EXT4_I(inode)->i_file_acl);
375                 error = -EIO;
376                 goto cleanup;
377         }
378         ext4_xattr_cache_insert(bh);
379         error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
380
381 cleanup:
382         brelse(bh);
383
384         return error;
385 }
386
387 static int
388 ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
389 {
390         struct ext4_xattr_ibody_header *header;
391         struct ext4_inode *raw_inode;
392         struct ext4_iloc iloc;
393         void *end;
394         int error;
395
396         if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
397                 return 0;
398         error = ext4_get_inode_loc(inode, &iloc);
399         if (error)
400                 return error;
401         raw_inode = ext4_raw_inode(&iloc);
402         header = IHDR(inode, raw_inode);
403         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
404         error = ext4_xattr_check_names(IFIRST(header), end);
405         if (error)
406                 goto cleanup;
407         error = ext4_xattr_list_entries(inode, IFIRST(header),
408                                         buffer, buffer_size);
409
410 cleanup:
411         brelse(iloc.bh);
412         return error;
413 }
414
415 /*
416  * ext4_xattr_list()
417  *
418  * Copy a list of attribute names into the buffer
419  * provided, or compute the buffer size required.
420  * Buffer is NULL to compute the size of the buffer required.
421  *
422  * Returns a negative error number on failure, or the number of bytes
423  * used / required on success.
424  */
425 static int
426 ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
427 {
428         int i_error, b_error;
429
430         down_read(&EXT4_I(inode)->xattr_sem);
431         i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size);
432         if (i_error < 0) {
433                 b_error = 0;
434         } else {
435                 if (buffer) {
436                         buffer += i_error;
437                         buffer_size -= i_error;
438                 }
439                 b_error = ext4_xattr_block_list(inode, buffer, buffer_size);
440                 if (b_error < 0)
441                         i_error = 0;
442         }
443         up_read(&EXT4_I(inode)->xattr_sem);
444         return i_error + b_error;
445 }
446
447 /*
448  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
449  * not set, set it.
450  */
451 static void ext4_xattr_update_super_block(handle_t *handle,
452                                           struct super_block *sb)
453 {
454         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
455                 return;
456
457         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
458                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
459                 sb->s_dirt = 1;
460                 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
461         }
462 }
463
464 /*
465  * Release the xattr block BH: If the reference count is > 1, decrement
466  * it; otherwise free the block.
467  */
468 static void
469 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
470                          struct buffer_head *bh)
471 {
472         struct mb_cache_entry *ce = NULL;
473         int error = 0;
474
475         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
476         error = ext4_journal_get_write_access(handle, bh);
477         if (error)
478                 goto out;
479
480         lock_buffer(bh);
481         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
482                 ea_bdebug(bh, "refcount now=0; freeing");
483                 if (ce)
484                         mb_cache_entry_free(ce);
485                 ext4_free_blocks(handle, inode, bh->b_blocknr, 1, 1);
486                 get_bh(bh);
487                 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
488         } else {
489                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
490                 error = ext4_journal_dirty_metadata(handle, bh);
491                 if (IS_SYNC(inode))
492                         handle->h_sync = 1;
493                 DQUOT_FREE_BLOCK(inode, 1);
494                 ea_bdebug(bh, "refcount now=%d; releasing",
495                           le32_to_cpu(BHDR(bh)->h_refcount));
496                 if (ce)
497                         mb_cache_entry_release(ce);
498         }
499         unlock_buffer(bh);
500 out:
501         ext4_std_error(inode->i_sb, error);
502         return;
503 }
504
505 /*
506  * Find the available free space for EAs. This also returns the total number of
507  * bytes used by EA entries.
508  */
509 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
510                                     size_t *min_offs, void *base, int *total)
511 {
512         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
513                 *total += EXT4_XATTR_LEN(last->e_name_len);
514                 if (!last->e_value_block && last->e_value_size) {
515                         size_t offs = le16_to_cpu(last->e_value_offs);
516                         if (offs < *min_offs)
517                                 *min_offs = offs;
518                 }
519         }
520         return (*min_offs - ((void *)last - base) - sizeof(__u32));
521 }
522
523 struct ext4_xattr_info {
524         int name_index;
525         const char *name;
526         const void *value;
527         size_t value_len;
528 };
529
530 struct ext4_xattr_search {
531         struct ext4_xattr_entry *first;
532         void *base;
533         void *end;
534         struct ext4_xattr_entry *here;
535         int not_found;
536 };
537
538 static int
539 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
540 {
541         struct ext4_xattr_entry *last;
542         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
543
544         /* Compute min_offs and last. */
545         last = s->first;
546         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
547                 if (!last->e_value_block && last->e_value_size) {
548                         size_t offs = le16_to_cpu(last->e_value_offs);
549                         if (offs < min_offs)
550                                 min_offs = offs;
551                 }
552         }
553         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
554         if (!s->not_found) {
555                 if (!s->here->e_value_block && s->here->e_value_size) {
556                         size_t size = le32_to_cpu(s->here->e_value_size);
557                         free += EXT4_XATTR_SIZE(size);
558                 }
559                 free += EXT4_XATTR_LEN(name_len);
560         }
561         if (i->value) {
562                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
563                     free < EXT4_XATTR_LEN(name_len) +
564                            EXT4_XATTR_SIZE(i->value_len))
565                         return -ENOSPC;
566         }
567
568         if (i->value && s->not_found) {
569                 /* Insert the new name. */
570                 size_t size = EXT4_XATTR_LEN(name_len);
571                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
572                 memmove((void *)s->here + size, s->here, rest);
573                 memset(s->here, 0, size);
574                 s->here->e_name_index = i->name_index;
575                 s->here->e_name_len = name_len;
576                 memcpy(s->here->e_name, i->name, name_len);
577         } else {
578                 if (!s->here->e_value_block && s->here->e_value_size) {
579                         void *first_val = s->base + min_offs;
580                         size_t offs = le16_to_cpu(s->here->e_value_offs);
581                         void *val = s->base + offs;
582                         size_t size = EXT4_XATTR_SIZE(
583                                 le32_to_cpu(s->here->e_value_size));
584
585                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
586                                 /* The old and the new value have the same
587                                    size. Just replace. */
588                                 s->here->e_value_size =
589                                         cpu_to_le32(i->value_len);
590                                 memset(val + size - EXT4_XATTR_PAD, 0,
591                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
592                                 memcpy(val, i->value, i->value_len);
593                                 return 0;
594                         }
595
596                         /* Remove the old value. */
597                         memmove(first_val + size, first_val, val - first_val);
598                         memset(first_val, 0, size);
599                         s->here->e_value_size = 0;
600                         s->here->e_value_offs = 0;
601                         min_offs += size;
602
603                         /* Adjust all value offsets. */
604                         last = s->first;
605                         while (!IS_LAST_ENTRY(last)) {
606                                 size_t o = le16_to_cpu(last->e_value_offs);
607                                 if (!last->e_value_block &&
608                                     last->e_value_size && o < offs)
609                                         last->e_value_offs =
610                                                 cpu_to_le16(o + size);
611                                 last = EXT4_XATTR_NEXT(last);
612                         }
613                 }
614                 if (!i->value) {
615                         /* Remove the old name. */
616                         size_t size = EXT4_XATTR_LEN(name_len);
617                         last = ENTRY((void *)last - size);
618                         memmove(s->here, (void *)s->here + size,
619                                 (void *)last - (void *)s->here + sizeof(__u32));
620                         memset(last, 0, size);
621                 }
622         }
623
624         if (i->value) {
625                 /* Insert the new value. */
626                 s->here->e_value_size = cpu_to_le32(i->value_len);
627                 if (i->value_len) {
628                         size_t size = EXT4_XATTR_SIZE(i->value_len);
629                         void *val = s->base + min_offs - size;
630                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
631                         memset(val + size - EXT4_XATTR_PAD, 0,
632                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
633                         memcpy(val, i->value, i->value_len);
634                 }
635         }
636         return 0;
637 }
638
639 struct ext4_xattr_block_find {
640         struct ext4_xattr_search s;
641         struct buffer_head *bh;
642 };
643
644 static int
645 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
646                       struct ext4_xattr_block_find *bs)
647 {
648         struct super_block *sb = inode->i_sb;
649         int error;
650
651         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
652                   i->name_index, i->name, i->value, (long)i->value_len);
653
654         if (EXT4_I(inode)->i_file_acl) {
655                 /* The inode already has an extended attribute block. */
656                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
657                 error = -EIO;
658                 if (!bs->bh)
659                         goto cleanup;
660                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
661                         atomic_read(&(bs->bh->b_count)),
662                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
663                 if (ext4_xattr_check_block(bs->bh)) {
664                         ext4_error(sb, __func__,
665                                 "inode %lu: bad block %llu", inode->i_ino,
666                                 EXT4_I(inode)->i_file_acl);
667                         error = -EIO;
668                         goto cleanup;
669                 }
670                 /* Find the named attribute. */
671                 bs->s.base = BHDR(bs->bh);
672                 bs->s.first = BFIRST(bs->bh);
673                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
674                 bs->s.here = bs->s.first;
675                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
676                                               i->name, bs->bh->b_size, 1);
677                 if (error && error != -ENODATA)
678                         goto cleanup;
679                 bs->s.not_found = error;
680         }
681         error = 0;
682
683 cleanup:
684         return error;
685 }
686
687 static int
688 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
689                      struct ext4_xattr_info *i,
690                      struct ext4_xattr_block_find *bs)
691 {
692         struct super_block *sb = inode->i_sb;
693         struct buffer_head *new_bh = NULL;
694         struct ext4_xattr_search *s = &bs->s;
695         struct mb_cache_entry *ce = NULL;
696         int error = 0;
697
698 #define header(x) ((struct ext4_xattr_header *)(x))
699
700         if (i->value && i->value_len > sb->s_blocksize)
701                 return -ENOSPC;
702         if (s->base) {
703                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
704                                         bs->bh->b_blocknr);
705                 error = ext4_journal_get_write_access(handle, bs->bh);
706                 if (error)
707                         goto cleanup;
708                 lock_buffer(bs->bh);
709
710                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
711                         if (ce) {
712                                 mb_cache_entry_free(ce);
713                                 ce = NULL;
714                         }
715                         ea_bdebug(bs->bh, "modifying in-place");
716                         error = ext4_xattr_set_entry(i, s);
717                         if (!error) {
718                                 if (!IS_LAST_ENTRY(s->first))
719                                         ext4_xattr_rehash(header(s->base),
720                                                           s->here);
721                                 ext4_xattr_cache_insert(bs->bh);
722                         }
723                         unlock_buffer(bs->bh);
724                         if (error == -EIO)
725                                 goto bad_block;
726                         if (!error)
727                                 error = ext4_journal_dirty_metadata(handle,
728                                                                     bs->bh);
729                         if (error)
730                                 goto cleanup;
731                         goto inserted;
732                 } else {
733                         int offset = (char *)s->here - bs->bh->b_data;
734
735                         unlock_buffer(bs->bh);
736                         jbd2_journal_release_buffer(handle, bs->bh);
737                         if (ce) {
738                                 mb_cache_entry_release(ce);
739                                 ce = NULL;
740                         }
741                         ea_bdebug(bs->bh, "cloning");
742                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
743                         error = -ENOMEM;
744                         if (s->base == NULL)
745                                 goto cleanup;
746                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
747                         s->first = ENTRY(header(s->base)+1);
748                         header(s->base)->h_refcount = cpu_to_le32(1);
749                         s->here = ENTRY(s->base + offset);
750                         s->end = s->base + bs->bh->b_size;
751                 }
752         } else {
753                 /* Allocate a buffer where we construct the new block. */
754                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
755                 /* assert(header == s->base) */
756                 error = -ENOMEM;
757                 if (s->base == NULL)
758                         goto cleanup;
759                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
760                 header(s->base)->h_blocks = cpu_to_le32(1);
761                 header(s->base)->h_refcount = cpu_to_le32(1);
762                 s->first = ENTRY(header(s->base)+1);
763                 s->here = ENTRY(header(s->base)+1);
764                 s->end = s->base + sb->s_blocksize;
765         }
766
767         error = ext4_xattr_set_entry(i, s);
768         if (error == -EIO)
769                 goto bad_block;
770         if (error)
771                 goto cleanup;
772         if (!IS_LAST_ENTRY(s->first))
773                 ext4_xattr_rehash(header(s->base), s->here);
774
775 inserted:
776         if (!IS_LAST_ENTRY(s->first)) {
777                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
778                 if (new_bh) {
779                         /* We found an identical block in the cache. */
780                         if (new_bh == bs->bh)
781                                 ea_bdebug(new_bh, "keeping");
782                         else {
783                                 /* The old block is released after updating
784                                    the inode. */
785                                 error = -EDQUOT;
786                                 if (DQUOT_ALLOC_BLOCK(inode, 1))
787                                         goto cleanup;
788                                 error = ext4_journal_get_write_access(handle,
789                                                                       new_bh);
790                                 if (error)
791                                         goto cleanup_dquot;
792                                 lock_buffer(new_bh);
793                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
794                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
795                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
796                                 unlock_buffer(new_bh);
797                                 error = ext4_journal_dirty_metadata(handle,
798                                                                     new_bh);
799                                 if (error)
800                                         goto cleanup_dquot;
801                         }
802                         mb_cache_entry_release(ce);
803                         ce = NULL;
804                 } else if (bs->bh && s->base == bs->bh->b_data) {
805                         /* We were modifying this block in-place. */
806                         ea_bdebug(bs->bh, "keeping this block");
807                         new_bh = bs->bh;
808                         get_bh(new_bh);
809                 } else {
810                         /* We need to allocate a new block */
811                         ext4_fsblk_t goal = ext4_group_first_block_no(sb,
812                                                 EXT4_I(inode)->i_block_group);
813                         ext4_fsblk_t block = ext4_new_meta_block(handle, inode,
814                                                         goal, &error);
815                         if (error)
816                                 goto cleanup;
817                         ea_idebug(inode, "creating block %d", block);
818
819                         new_bh = sb_getblk(sb, block);
820                         if (!new_bh) {
821 getblk_failed:
822                                 ext4_free_blocks(handle, inode, block, 1, 1);
823                                 error = -EIO;
824                                 goto cleanup;
825                         }
826                         lock_buffer(new_bh);
827                         error = ext4_journal_get_create_access(handle, new_bh);
828                         if (error) {
829                                 unlock_buffer(new_bh);
830                                 goto getblk_failed;
831                         }
832                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
833                         set_buffer_uptodate(new_bh);
834                         unlock_buffer(new_bh);
835                         ext4_xattr_cache_insert(new_bh);
836                         error = ext4_journal_dirty_metadata(handle, new_bh);
837                         if (error)
838                                 goto cleanup;
839                 }
840         }
841
842         /* Update the inode. */
843         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
844
845         /* Drop the previous xattr block. */
846         if (bs->bh && bs->bh != new_bh)
847                 ext4_xattr_release_block(handle, inode, bs->bh);
848         error = 0;
849
850 cleanup:
851         if (ce)
852                 mb_cache_entry_release(ce);
853         brelse(new_bh);
854         if (!(bs->bh && s->base == bs->bh->b_data))
855                 kfree(s->base);
856
857         return error;
858
859 cleanup_dquot:
860         DQUOT_FREE_BLOCK(inode, 1);
861         goto cleanup;
862
863 bad_block:
864         ext4_error(inode->i_sb, __func__,
865                    "inode %lu: bad block %llu", inode->i_ino,
866                    EXT4_I(inode)->i_file_acl);
867         goto cleanup;
868
869 #undef header
870 }
871
872 struct ext4_xattr_ibody_find {
873         struct ext4_xattr_search s;
874         struct ext4_iloc iloc;
875 };
876
877 static int
878 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
879                       struct ext4_xattr_ibody_find *is)
880 {
881         struct ext4_xattr_ibody_header *header;
882         struct ext4_inode *raw_inode;
883         int error;
884
885         if (EXT4_I(inode)->i_extra_isize == 0)
886                 return 0;
887         raw_inode = ext4_raw_inode(&is->iloc);
888         header = IHDR(inode, raw_inode);
889         is->s.base = is->s.first = IFIRST(header);
890         is->s.here = is->s.first;
891         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
892         if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
893                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
894                 if (error)
895                         return error;
896                 /* Find the named attribute. */
897                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
898                                               i->name, is->s.end -
899                                               (void *)is->s.base, 0);
900                 if (error && error != -ENODATA)
901                         return error;
902                 is->s.not_found = error;
903         }
904         return 0;
905 }
906
907 static int
908 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
909                      struct ext4_xattr_info *i,
910                      struct ext4_xattr_ibody_find *is)
911 {
912         struct ext4_xattr_ibody_header *header;
913         struct ext4_xattr_search *s = &is->s;
914         int error;
915
916         if (EXT4_I(inode)->i_extra_isize == 0)
917                 return -ENOSPC;
918         error = ext4_xattr_set_entry(i, s);
919         if (error)
920                 return error;
921         header = IHDR(inode, ext4_raw_inode(&is->iloc));
922         if (!IS_LAST_ENTRY(s->first)) {
923                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
924                 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
925         } else {
926                 header->h_magic = cpu_to_le32(0);
927                 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
928         }
929         return 0;
930 }
931
932 /*
933  * ext4_xattr_set_handle()
934  *
935  * Create, replace or remove an extended attribute for this inode. Buffer
936  * is NULL to remove an existing extended attribute, and non-NULL to
937  * either replace an existing extended attribute, or create a new extended
938  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
939  * specify that an extended attribute must exist and must not exist
940  * previous to the call, respectively.
941  *
942  * Returns 0, or a negative error number on failure.
943  */
944 int
945 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
946                       const char *name, const void *value, size_t value_len,
947                       int flags)
948 {
949         struct ext4_xattr_info i = {
950                 .name_index = name_index,
951                 .name = name,
952                 .value = value,
953                 .value_len = value_len,
954
955         };
956         struct ext4_xattr_ibody_find is = {
957                 .s = { .not_found = -ENODATA, },
958         };
959         struct ext4_xattr_block_find bs = {
960                 .s = { .not_found = -ENODATA, },
961         };
962         int error;
963
964         if (!name)
965                 return -EINVAL;
966         if (strlen(name) > 255)
967                 return -ERANGE;
968         down_write(&EXT4_I(inode)->xattr_sem);
969         error = ext4_get_inode_loc(inode, &is.iloc);
970         if (error)
971                 goto cleanup;
972
973         if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
974                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
975                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
976                 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
977         }
978
979         error = ext4_xattr_ibody_find(inode, &i, &is);
980         if (error)
981                 goto cleanup;
982         if (is.s.not_found)
983                 error = ext4_xattr_block_find(inode, &i, &bs);
984         if (error)
985                 goto cleanup;
986         if (is.s.not_found && bs.s.not_found) {
987                 error = -ENODATA;
988                 if (flags & XATTR_REPLACE)
989                         goto cleanup;
990                 error = 0;
991                 if (!value)
992                         goto cleanup;
993         } else {
994                 error = -EEXIST;
995                 if (flags & XATTR_CREATE)
996                         goto cleanup;
997         }
998         error = ext4_journal_get_write_access(handle, is.iloc.bh);
999         if (error)
1000                 goto cleanup;
1001         if (!value) {
1002                 if (!is.s.not_found)
1003                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1004                 else if (!bs.s.not_found)
1005                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1006         } else {
1007                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1008                 if (!error && !bs.s.not_found) {
1009                         i.value = NULL;
1010                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1011                 } else if (error == -ENOSPC) {
1012                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1013                                 error = ext4_xattr_block_find(inode, &i, &bs);
1014                                 if (error)
1015                                         goto cleanup;
1016                         }
1017                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1018                         if (error)
1019                                 goto cleanup;
1020                         if (!is.s.not_found) {
1021                                 i.value = NULL;
1022                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1023                                                              &is);
1024                         }
1025                 }
1026         }
1027         if (!error) {
1028                 ext4_xattr_update_super_block(handle, inode->i_sb);
1029                 inode->i_ctime = ext4_current_time(inode);
1030                 if (!value)
1031                         EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1032                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1033                 /*
1034                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1035                  * error != 0.
1036                  */
1037                 is.iloc.bh = NULL;
1038                 if (IS_SYNC(inode))
1039                         handle->h_sync = 1;
1040         }
1041
1042 cleanup:
1043         brelse(is.iloc.bh);
1044         brelse(bs.bh);
1045         up_write(&EXT4_I(inode)->xattr_sem);
1046         return error;
1047 }
1048
1049 /*
1050  * ext4_xattr_set()
1051  *
1052  * Like ext4_xattr_set_handle, but start from an inode. This extended
1053  * attribute modification is a filesystem transaction by itself.
1054  *
1055  * Returns 0, or a negative error number on failure.
1056  */
1057 int
1058 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1059                const void *value, size_t value_len, int flags)
1060 {
1061         handle_t *handle;
1062         int error, retries = 0;
1063
1064 retry:
1065         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1066         if (IS_ERR(handle)) {
1067                 error = PTR_ERR(handle);
1068         } else {
1069                 int error2;
1070
1071                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1072                                               value, value_len, flags);
1073                 error2 = ext4_journal_stop(handle);
1074                 if (error == -ENOSPC &&
1075                     ext4_should_retry_alloc(inode->i_sb, &retries))
1076                         goto retry;
1077                 if (error == 0)
1078                         error = error2;
1079         }
1080
1081         return error;
1082 }
1083
1084 /*
1085  * Shift the EA entries in the inode to create space for the increased
1086  * i_extra_isize.
1087  */
1088 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1089                                      int value_offs_shift, void *to,
1090                                      void *from, size_t n, int blocksize)
1091 {
1092         struct ext4_xattr_entry *last = entry;
1093         int new_offs;
1094
1095         /* Adjust the value offsets of the entries */
1096         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1097                 if (!last->e_value_block && last->e_value_size) {
1098                         new_offs = le16_to_cpu(last->e_value_offs) +
1099                                                         value_offs_shift;
1100                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1101                                  > blocksize);
1102                         last->e_value_offs = cpu_to_le16(new_offs);
1103                 }
1104         }
1105         /* Shift the entries by n bytes */
1106         memmove(to, from, n);
1107 }
1108
1109 /*
1110  * Expand an inode by new_extra_isize bytes when EAs are present.
1111  * Returns 0 on success or negative error number on failure.
1112  */
1113 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1114                                struct ext4_inode *raw_inode, handle_t *handle)
1115 {
1116         struct ext4_xattr_ibody_header *header;
1117         struct ext4_xattr_entry *entry, *last, *first;
1118         struct buffer_head *bh = NULL;
1119         struct ext4_xattr_ibody_find *is = NULL;
1120         struct ext4_xattr_block_find *bs = NULL;
1121         char *buffer = NULL, *b_entry_name = NULL;
1122         size_t min_offs, free;
1123         int total_ino, total_blk;
1124         void *base, *start, *end;
1125         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1126         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1127
1128         down_write(&EXT4_I(inode)->xattr_sem);
1129 retry:
1130         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1131                 up_write(&EXT4_I(inode)->xattr_sem);
1132                 return 0;
1133         }
1134
1135         header = IHDR(inode, raw_inode);
1136         entry = IFIRST(header);
1137
1138         /*
1139          * Check if enough free space is available in the inode to shift the
1140          * entries ahead by new_extra_isize.
1141          */
1142
1143         base = start = entry;
1144         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1145         min_offs = end - base;
1146         last = entry;
1147         total_ino = sizeof(struct ext4_xattr_ibody_header);
1148
1149         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1150         if (free >= new_extra_isize) {
1151                 entry = IFIRST(header);
1152                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1153                                 - new_extra_isize, (void *)raw_inode +
1154                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1155                                 (void *)header, total_ino,
1156                                 inode->i_sb->s_blocksize);
1157                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1158                 error = 0;
1159                 goto cleanup;
1160         }
1161
1162         /*
1163          * Enough free space isn't available in the inode, check if
1164          * EA block can hold new_extra_isize bytes.
1165          */
1166         if (EXT4_I(inode)->i_file_acl) {
1167                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1168                 error = -EIO;
1169                 if (!bh)
1170                         goto cleanup;
1171                 if (ext4_xattr_check_block(bh)) {
1172                         ext4_error(inode->i_sb, __func__,
1173                                 "inode %lu: bad block %llu", inode->i_ino,
1174                                 EXT4_I(inode)->i_file_acl);
1175                         error = -EIO;
1176                         goto cleanup;
1177                 }
1178                 base = BHDR(bh);
1179                 first = BFIRST(bh);
1180                 end = bh->b_data + bh->b_size;
1181                 min_offs = end - base;
1182                 free = ext4_xattr_free_space(first, &min_offs, base,
1183                                              &total_blk);
1184                 if (free < new_extra_isize) {
1185                         if (!tried_min_extra_isize && s_min_extra_isize) {
1186                                 tried_min_extra_isize++;
1187                                 new_extra_isize = s_min_extra_isize;
1188                                 brelse(bh);
1189                                 goto retry;
1190                         }
1191                         error = -1;
1192                         goto cleanup;
1193                 }
1194         } else {
1195                 free = inode->i_sb->s_blocksize;
1196         }
1197
1198         while (new_extra_isize > 0) {
1199                 size_t offs, size, entry_size;
1200                 struct ext4_xattr_entry *small_entry = NULL;
1201                 struct ext4_xattr_info i = {
1202                         .value = NULL,
1203                         .value_len = 0,
1204                 };
1205                 unsigned int total_size;  /* EA entry size + value size */
1206                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1207                 unsigned int min_total_size = ~0U;
1208
1209                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1210                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1211                 if (!is || !bs) {
1212                         error = -ENOMEM;
1213                         goto cleanup;
1214                 }
1215
1216                 is->s.not_found = -ENODATA;
1217                 bs->s.not_found = -ENODATA;
1218                 is->iloc.bh = NULL;
1219                 bs->bh = NULL;
1220
1221                 last = IFIRST(header);
1222                 /* Find the entry best suited to be pushed into EA block */
1223                 entry = NULL;
1224                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1225                         total_size =
1226                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1227                                         EXT4_XATTR_LEN(last->e_name_len);
1228                         if (total_size <= free && total_size < min_total_size) {
1229                                 if (total_size < new_extra_isize) {
1230                                         small_entry = last;
1231                                 } else {
1232                                         entry = last;
1233                                         min_total_size = total_size;
1234                                 }
1235                         }
1236                 }
1237
1238                 if (entry == NULL) {
1239                         if (small_entry) {
1240                                 entry = small_entry;
1241                         } else {
1242                                 if (!tried_min_extra_isize &&
1243                                     s_min_extra_isize) {
1244                                         tried_min_extra_isize++;
1245                                         new_extra_isize = s_min_extra_isize;
1246                                         goto retry;
1247                                 }
1248                                 error = -1;
1249                                 goto cleanup;
1250                         }
1251                 }
1252                 offs = le16_to_cpu(entry->e_value_offs);
1253                 size = le32_to_cpu(entry->e_value_size);
1254                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1255                 i.name_index = entry->e_name_index,
1256                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1257                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1258                 if (!buffer || !b_entry_name) {
1259                         error = -ENOMEM;
1260                         goto cleanup;
1261                 }
1262                 /* Save the entry name and the entry value */
1263                 memcpy(buffer, (void *)IFIRST(header) + offs,
1264                        EXT4_XATTR_SIZE(size));
1265                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1266                 b_entry_name[entry->e_name_len] = '\0';
1267                 i.name = b_entry_name;
1268
1269                 error = ext4_get_inode_loc(inode, &is->iloc);
1270                 if (error)
1271                         goto cleanup;
1272
1273                 error = ext4_xattr_ibody_find(inode, &i, is);
1274                 if (error)
1275                         goto cleanup;
1276
1277                 /* Remove the chosen entry from the inode */
1278                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1279
1280                 entry = IFIRST(header);
1281                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1282                         shift_bytes = new_extra_isize;
1283                 else
1284                         shift_bytes = entry_size + size;
1285                 /* Adjust the offsets and shift the remaining entries ahead */
1286                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1287                         shift_bytes, (void *)raw_inode +
1288                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1289                         (void *)header, total_ino - entry_size,
1290                         inode->i_sb->s_blocksize);
1291
1292                 extra_isize += shift_bytes;
1293                 new_extra_isize -= shift_bytes;
1294                 EXT4_I(inode)->i_extra_isize = extra_isize;
1295
1296                 i.name = b_entry_name;
1297                 i.value = buffer;
1298                 i.value_len = size;
1299                 error = ext4_xattr_block_find(inode, &i, bs);
1300                 if (error)
1301                         goto cleanup;
1302
1303                 /* Add entry which was removed from the inode into the block */
1304                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1305                 if (error)
1306                         goto cleanup;
1307                 kfree(b_entry_name);
1308                 kfree(buffer);
1309                 brelse(is->iloc.bh);
1310                 kfree(is);
1311                 kfree(bs);
1312         }
1313         brelse(bh);
1314         up_write(&EXT4_I(inode)->xattr_sem);
1315         return 0;
1316
1317 cleanup:
1318         kfree(b_entry_name);
1319         kfree(buffer);
1320         if (is)
1321                 brelse(is->iloc.bh);
1322         kfree(is);
1323         kfree(bs);
1324         brelse(bh);
1325         up_write(&EXT4_I(inode)->xattr_sem);
1326         return error;
1327 }
1328
1329
1330
1331 /*
1332  * ext4_xattr_delete_inode()
1333  *
1334  * Free extended attribute resources associated with this inode. This
1335  * is called immediately before an inode is freed. We have exclusive
1336  * access to the inode.
1337  */
1338 void
1339 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1340 {
1341         struct buffer_head *bh = NULL;
1342
1343         if (!EXT4_I(inode)->i_file_acl)
1344                 goto cleanup;
1345         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1346         if (!bh) {
1347                 ext4_error(inode->i_sb, __func__,
1348                         "inode %lu: block %llu read error", inode->i_ino,
1349                         EXT4_I(inode)->i_file_acl);
1350                 goto cleanup;
1351         }
1352         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1353             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1354                 ext4_error(inode->i_sb, __func__,
1355                         "inode %lu: bad block %llu", inode->i_ino,
1356                         EXT4_I(inode)->i_file_acl);
1357                 goto cleanup;
1358         }
1359         ext4_xattr_release_block(handle, inode, bh);
1360         EXT4_I(inode)->i_file_acl = 0;
1361
1362 cleanup:
1363         brelse(bh);
1364 }
1365
1366 /*
1367  * ext4_xattr_put_super()
1368  *
1369  * This is called when a file system is unmounted.
1370  */
1371 void
1372 ext4_xattr_put_super(struct super_block *sb)
1373 {
1374         mb_cache_shrink(sb->s_bdev);
1375 }
1376
1377 /*
1378  * ext4_xattr_cache_insert()
1379  *
1380  * Create a new entry in the extended attribute cache, and insert
1381  * it unless such an entry is already in the cache.
1382  *
1383  * Returns 0, or a negative error number on failure.
1384  */
1385 static void
1386 ext4_xattr_cache_insert(struct buffer_head *bh)
1387 {
1388         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1389         struct mb_cache_entry *ce;
1390         int error;
1391
1392         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1393         if (!ce) {
1394                 ea_bdebug(bh, "out of memory");
1395                 return;
1396         }
1397         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1398         if (error) {
1399                 mb_cache_entry_free(ce);
1400                 if (error == -EBUSY) {
1401                         ea_bdebug(bh, "already in cache");
1402                         error = 0;
1403                 }
1404         } else {
1405                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1406                 mb_cache_entry_release(ce);
1407         }
1408 }
1409
1410 /*
1411  * ext4_xattr_cmp()
1412  *
1413  * Compare two extended attribute blocks for equality.
1414  *
1415  * Returns 0 if the blocks are equal, 1 if they differ, and
1416  * a negative error number on errors.
1417  */
1418 static int
1419 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1420                struct ext4_xattr_header *header2)
1421 {
1422         struct ext4_xattr_entry *entry1, *entry2;
1423
1424         entry1 = ENTRY(header1+1);
1425         entry2 = ENTRY(header2+1);
1426         while (!IS_LAST_ENTRY(entry1)) {
1427                 if (IS_LAST_ENTRY(entry2))
1428                         return 1;
1429                 if (entry1->e_hash != entry2->e_hash ||
1430                     entry1->e_name_index != entry2->e_name_index ||
1431                     entry1->e_name_len != entry2->e_name_len ||
1432                     entry1->e_value_size != entry2->e_value_size ||
1433                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1434                         return 1;
1435                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1436                         return -EIO;
1437                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1438                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1439                            le32_to_cpu(entry1->e_value_size)))
1440                         return 1;
1441
1442                 entry1 = EXT4_XATTR_NEXT(entry1);
1443                 entry2 = EXT4_XATTR_NEXT(entry2);
1444         }
1445         if (!IS_LAST_ENTRY(entry2))
1446                 return 1;
1447         return 0;
1448 }
1449
1450 /*
1451  * ext4_xattr_cache_find()
1452  *
1453  * Find an identical extended attribute block.
1454  *
1455  * Returns a pointer to the block found, or NULL if such a block was
1456  * not found or an error occurred.
1457  */
1458 static struct buffer_head *
1459 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1460                       struct mb_cache_entry **pce)
1461 {
1462         __u32 hash = le32_to_cpu(header->h_hash);
1463         struct mb_cache_entry *ce;
1464
1465         if (!header->h_hash)
1466                 return NULL;  /* never share */
1467         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1468 again:
1469         ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1470                                        inode->i_sb->s_bdev, hash);
1471         while (ce) {
1472                 struct buffer_head *bh;
1473
1474                 if (IS_ERR(ce)) {
1475                         if (PTR_ERR(ce) == -EAGAIN)
1476                                 goto again;
1477                         break;
1478                 }
1479                 bh = sb_bread(inode->i_sb, ce->e_block);
1480                 if (!bh) {
1481                         ext4_error(inode->i_sb, __func__,
1482                                 "inode %lu: block %lu read error",
1483                                 inode->i_ino, (unsigned long) ce->e_block);
1484                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1485                                 EXT4_XATTR_REFCOUNT_MAX) {
1486                         ea_idebug(inode, "block %lu refcount %d>=%d",
1487                                   (unsigned long) ce->e_block,
1488                                   le32_to_cpu(BHDR(bh)->h_refcount),
1489                                           EXT4_XATTR_REFCOUNT_MAX);
1490                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1491                         *pce = ce;
1492                         return bh;
1493                 }
1494                 brelse(bh);
1495                 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1496         }
1497         return NULL;
1498 }
1499
1500 #define NAME_HASH_SHIFT 5
1501 #define VALUE_HASH_SHIFT 16
1502
1503 /*
1504  * ext4_xattr_hash_entry()
1505  *
1506  * Compute the hash of an extended attribute.
1507  */
1508 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1509                                          struct ext4_xattr_entry *entry)
1510 {
1511         __u32 hash = 0;
1512         char *name = entry->e_name;
1513         int n;
1514
1515         for (n = 0; n < entry->e_name_len; n++) {
1516                 hash = (hash << NAME_HASH_SHIFT) ^
1517                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1518                        *name++;
1519         }
1520
1521         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1522                 __le32 *value = (__le32 *)((char *)header +
1523                         le16_to_cpu(entry->e_value_offs));
1524                 for (n = (le32_to_cpu(entry->e_value_size) +
1525                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1526                         hash = (hash << VALUE_HASH_SHIFT) ^
1527                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1528                                le32_to_cpu(*value++);
1529                 }
1530         }
1531         entry->e_hash = cpu_to_le32(hash);
1532 }
1533
1534 #undef NAME_HASH_SHIFT
1535 #undef VALUE_HASH_SHIFT
1536
1537 #define BLOCK_HASH_SHIFT 16
1538
1539 /*
1540  * ext4_xattr_rehash()
1541  *
1542  * Re-compute the extended attribute hash value after an entry has changed.
1543  */
1544 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1545                               struct ext4_xattr_entry *entry)
1546 {
1547         struct ext4_xattr_entry *here;
1548         __u32 hash = 0;
1549
1550         ext4_xattr_hash_entry(header, entry);
1551         here = ENTRY(header+1);
1552         while (!IS_LAST_ENTRY(here)) {
1553                 if (!here->e_hash) {
1554                         /* Block is not shared if an entry's hash value == 0 */
1555                         hash = 0;
1556                         break;
1557                 }
1558                 hash = (hash << BLOCK_HASH_SHIFT) ^
1559                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1560                        le32_to_cpu(here->e_hash);
1561                 here = EXT4_XATTR_NEXT(here);
1562         }
1563         header->h_hash = cpu_to_le32(hash);
1564 }
1565
1566 #undef BLOCK_HASH_SHIFT
1567
1568 int __init
1569 init_ext4_xattr(void)
1570 {
1571         ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1572                 sizeof(struct mb_cache_entry) +
1573                 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1574         if (!ext4_xattr_cache)
1575                 return -ENOMEM;
1576         return 0;
1577 }
1578
1579 void
1580 exit_ext4_xattr(void)
1581 {
1582         if (ext4_xattr_cache)
1583                 mb_cache_destroy(ext4_xattr_cache);
1584         ext4_xattr_cache = NULL;
1585 }