microblaze: Fix "kstack=" parsing
[linux-2.6.git] / fs / ext3 / xattr.c
1 /*
2  * linux/fs/ext3/xattr.c
3  *
4  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5  *
6  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7  * Ext3 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  * EXT3_I(inode)->i_file_acl is protected by EXT3_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/ext3_jbd.h>
57 #include <linux/ext3_fs.h>
58 #include <linux/mbcache.h>
59 #include <linux/quotaops.h>
60 #include <linux/rwsem.h>
61 #include "xattr.h"
62 #include "acl.h"
63
64 #define BHDR(bh) ((struct ext3_xattr_header *)((bh)->b_data))
65 #define ENTRY(ptr) ((struct ext3_xattr_entry *)(ptr))
66 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
68
69 #define IHDR(inode, raw_inode) \
70         ((struct ext3_xattr_ibody_header *) \
71                 ((void *)raw_inode + \
72                  EXT3_GOOD_OLD_INODE_SIZE + \
73                  EXT3_I(inode)->i_extra_isize))
74 #define IFIRST(hdr) ((struct ext3_xattr_entry *)((hdr)+1))
75
76 #ifdef EXT3_XATTR_DEBUG
77 # define ea_idebug(inode, f...) do { \
78                 printk(KERN_DEBUG "inode %s:%lu: ", \
79                         inode->i_sb->s_id, inode->i_ino); \
80                 printk(f); \
81                 printk("\n"); \
82         } while (0)
83 # define ea_bdebug(bh, f...) do { \
84                 char b[BDEVNAME_SIZE]; \
85                 printk(KERN_DEBUG "block %s:%lu: ", \
86                         bdevname(bh->b_bdev, b), \
87                         (unsigned long) bh->b_blocknr); \
88                 printk(f); \
89                 printk("\n"); \
90         } while (0)
91 #else
92 # define ea_idebug(f...)
93 # define ea_bdebug(f...)
94 #endif
95
96 static void ext3_xattr_cache_insert(struct buffer_head *);
97 static struct buffer_head *ext3_xattr_cache_find(struct inode *,
98                                                  struct ext3_xattr_header *,
99                                                  struct mb_cache_entry **);
100 static void ext3_xattr_rehash(struct ext3_xattr_header *,
101                               struct ext3_xattr_entry *);
102 static int ext3_xattr_list(struct dentry *dentry, char *buffer,
103                            size_t buffer_size);
104
105 static struct mb_cache *ext3_xattr_cache;
106
107 static struct xattr_handler *ext3_xattr_handler_map[] = {
108         [EXT3_XATTR_INDEX_USER]              = &ext3_xattr_user_handler,
109 #ifdef CONFIG_EXT3_FS_POSIX_ACL
110         [EXT3_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext3_xattr_acl_access_handler,
111         [EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext3_xattr_acl_default_handler,
112 #endif
113         [EXT3_XATTR_INDEX_TRUSTED]           = &ext3_xattr_trusted_handler,
114 #ifdef CONFIG_EXT3_FS_SECURITY
115         [EXT3_XATTR_INDEX_SECURITY]          = &ext3_xattr_security_handler,
116 #endif
117 };
118
119 struct xattr_handler *ext3_xattr_handlers[] = {
120         &ext3_xattr_user_handler,
121         &ext3_xattr_trusted_handler,
122 #ifdef CONFIG_EXT3_FS_POSIX_ACL
123         &ext3_xattr_acl_access_handler,
124         &ext3_xattr_acl_default_handler,
125 #endif
126 #ifdef CONFIG_EXT3_FS_SECURITY
127         &ext3_xattr_security_handler,
128 #endif
129         NULL
130 };
131
132 static inline struct xattr_handler *
133 ext3_xattr_handler(int name_index)
134 {
135         struct xattr_handler *handler = NULL;
136
137         if (name_index > 0 && name_index < ARRAY_SIZE(ext3_xattr_handler_map))
138                 handler = ext3_xattr_handler_map[name_index];
139         return handler;
140 }
141
142 /*
143  * Inode operation listxattr()
144  *
145  * dentry->d_inode->i_mutex: don't care
146  */
147 ssize_t
148 ext3_listxattr(struct dentry *dentry, char *buffer, size_t size)
149 {
150         return ext3_xattr_list(dentry, buffer, size);
151 }
152
153 static int
154 ext3_xattr_check_names(struct ext3_xattr_entry *entry, void *end)
155 {
156         while (!IS_LAST_ENTRY(entry)) {
157                 struct ext3_xattr_entry *next = EXT3_XATTR_NEXT(entry);
158                 if ((void *)next >= end)
159                         return -EIO;
160                 entry = next;
161         }
162         return 0;
163 }
164
165 static inline int
166 ext3_xattr_check_block(struct buffer_head *bh)
167 {
168         int error;
169
170         if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
171             BHDR(bh)->h_blocks != cpu_to_le32(1))
172                 return -EIO;
173         error = ext3_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
174         return error;
175 }
176
177 static inline int
178 ext3_xattr_check_entry(struct ext3_xattr_entry *entry, size_t size)
179 {
180         size_t value_size = le32_to_cpu(entry->e_value_size);
181
182         if (entry->e_value_block != 0 || value_size > size ||
183             le16_to_cpu(entry->e_value_offs) + value_size > size)
184                 return -EIO;
185         return 0;
186 }
187
188 static int
189 ext3_xattr_find_entry(struct ext3_xattr_entry **pentry, int name_index,
190                       const char *name, size_t size, int sorted)
191 {
192         struct ext3_xattr_entry *entry;
193         size_t name_len;
194         int cmp = 1;
195
196         if (name == NULL)
197                 return -EINVAL;
198         name_len = strlen(name);
199         entry = *pentry;
200         for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
201                 cmp = name_index - entry->e_name_index;
202                 if (!cmp)
203                         cmp = name_len - entry->e_name_len;
204                 if (!cmp)
205                         cmp = memcmp(name, entry->e_name, name_len);
206                 if (cmp <= 0 && (sorted || cmp == 0))
207                         break;
208         }
209         *pentry = entry;
210         if (!cmp && ext3_xattr_check_entry(entry, size))
211                         return -EIO;
212         return cmp ? -ENODATA : 0;
213 }
214
215 static int
216 ext3_xattr_block_get(struct inode *inode, int name_index, const char *name,
217                      void *buffer, size_t buffer_size)
218 {
219         struct buffer_head *bh = NULL;
220         struct ext3_xattr_entry *entry;
221         size_t size;
222         int error;
223
224         ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
225                   name_index, name, buffer, (long)buffer_size);
226
227         error = -ENODATA;
228         if (!EXT3_I(inode)->i_file_acl)
229                 goto cleanup;
230         ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
231         bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
232         if (!bh)
233                 goto cleanup;
234         ea_bdebug(bh, "b_count=%d, refcount=%d",
235                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
236         if (ext3_xattr_check_block(bh)) {
237 bad_block:      ext3_error(inode->i_sb, __func__,
238                            "inode %lu: bad block "E3FSBLK, inode->i_ino,
239                            EXT3_I(inode)->i_file_acl);
240                 error = -EIO;
241                 goto cleanup;
242         }
243         ext3_xattr_cache_insert(bh);
244         entry = BFIRST(bh);
245         error = ext3_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
246         if (error == -EIO)
247                 goto bad_block;
248         if (error)
249                 goto cleanup;
250         size = le32_to_cpu(entry->e_value_size);
251         if (buffer) {
252                 error = -ERANGE;
253                 if (size > buffer_size)
254                         goto cleanup;
255                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
256                        size);
257         }
258         error = size;
259
260 cleanup:
261         brelse(bh);
262         return error;
263 }
264
265 static int
266 ext3_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
267                      void *buffer, size_t buffer_size)
268 {
269         struct ext3_xattr_ibody_header *header;
270         struct ext3_xattr_entry *entry;
271         struct ext3_inode *raw_inode;
272         struct ext3_iloc iloc;
273         size_t size;
274         void *end;
275         int error;
276
277         if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
278                 return -ENODATA;
279         error = ext3_get_inode_loc(inode, &iloc);
280         if (error)
281                 return error;
282         raw_inode = ext3_raw_inode(&iloc);
283         header = IHDR(inode, raw_inode);
284         entry = IFIRST(header);
285         end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
286         error = ext3_xattr_check_names(entry, end);
287         if (error)
288                 goto cleanup;
289         error = ext3_xattr_find_entry(&entry, name_index, name,
290                                       end - (void *)entry, 0);
291         if (error)
292                 goto cleanup;
293         size = le32_to_cpu(entry->e_value_size);
294         if (buffer) {
295                 error = -ERANGE;
296                 if (size > buffer_size)
297                         goto cleanup;
298                 memcpy(buffer, (void *)IFIRST(header) +
299                        le16_to_cpu(entry->e_value_offs), size);
300         }
301         error = size;
302
303 cleanup:
304         brelse(iloc.bh);
305         return error;
306 }
307
308 /*
309  * ext3_xattr_get()
310  *
311  * Copy an extended attribute into the buffer
312  * provided, or compute the buffer size required.
313  * Buffer is NULL to compute the size of the buffer required.
314  *
315  * Returns a negative error number on failure, or the number of bytes
316  * used / required on success.
317  */
318 int
319 ext3_xattr_get(struct inode *inode, int name_index, const char *name,
320                void *buffer, size_t buffer_size)
321 {
322         int error;
323
324         down_read(&EXT3_I(inode)->xattr_sem);
325         error = ext3_xattr_ibody_get(inode, name_index, name, buffer,
326                                      buffer_size);
327         if (error == -ENODATA)
328                 error = ext3_xattr_block_get(inode, name_index, name, buffer,
329                                              buffer_size);
330         up_read(&EXT3_I(inode)->xattr_sem);
331         return error;
332 }
333
334 static int
335 ext3_xattr_list_entries(struct dentry *dentry, struct ext3_xattr_entry *entry,
336                         char *buffer, size_t buffer_size)
337 {
338         size_t rest = buffer_size;
339
340         for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
341                 struct xattr_handler *handler =
342                         ext3_xattr_handler(entry->e_name_index);
343
344                 if (handler) {
345                         size_t size = handler->list(dentry, buffer, rest,
346                                                     entry->e_name,
347                                                     entry->e_name_len,
348                                                     handler->flags);
349                         if (buffer) {
350                                 if (size > rest)
351                                         return -ERANGE;
352                                 buffer += size;
353                         }
354                         rest -= size;
355                 }
356         }
357         return buffer_size - rest;
358 }
359
360 static int
361 ext3_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
362 {
363         struct inode *inode = dentry->d_inode;
364         struct buffer_head *bh = NULL;
365         int error;
366
367         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
368                   buffer, (long)buffer_size);
369
370         error = 0;
371         if (!EXT3_I(inode)->i_file_acl)
372                 goto cleanup;
373         ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
374         bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
375         error = -EIO;
376         if (!bh)
377                 goto cleanup;
378         ea_bdebug(bh, "b_count=%d, refcount=%d",
379                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
380         if (ext3_xattr_check_block(bh)) {
381                 ext3_error(inode->i_sb, __func__,
382                            "inode %lu: bad block "E3FSBLK, inode->i_ino,
383                            EXT3_I(inode)->i_file_acl);
384                 error = -EIO;
385                 goto cleanup;
386         }
387         ext3_xattr_cache_insert(bh);
388         error = ext3_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
389
390 cleanup:
391         brelse(bh);
392
393         return error;
394 }
395
396 static int
397 ext3_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
398 {
399         struct inode *inode = dentry->d_inode;
400         struct ext3_xattr_ibody_header *header;
401         struct ext3_inode *raw_inode;
402         struct ext3_iloc iloc;
403         void *end;
404         int error;
405
406         if (!ext3_test_inode_state(inode, EXT3_STATE_XATTR))
407                 return 0;
408         error = ext3_get_inode_loc(inode, &iloc);
409         if (error)
410                 return error;
411         raw_inode = ext3_raw_inode(&iloc);
412         header = IHDR(inode, raw_inode);
413         end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
414         error = ext3_xattr_check_names(IFIRST(header), end);
415         if (error)
416                 goto cleanup;
417         error = ext3_xattr_list_entries(dentry, IFIRST(header),
418                                         buffer, buffer_size);
419
420 cleanup:
421         brelse(iloc.bh);
422         return error;
423 }
424
425 /*
426  * ext3_xattr_list()
427  *
428  * Copy a list of attribute names into the buffer
429  * provided, or compute the buffer size required.
430  * Buffer is NULL to compute the size of the buffer required.
431  *
432  * Returns a negative error number on failure, or the number of bytes
433  * used / required on success.
434  */
435 static int
436 ext3_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
437 {
438         int i_error, b_error;
439
440         down_read(&EXT3_I(dentry->d_inode)->xattr_sem);
441         i_error = ext3_xattr_ibody_list(dentry, buffer, buffer_size);
442         if (i_error < 0) {
443                 b_error = 0;
444         } else {
445                 if (buffer) {
446                         buffer += i_error;
447                         buffer_size -= i_error;
448                 }
449                 b_error = ext3_xattr_block_list(dentry, buffer, buffer_size);
450                 if (b_error < 0)
451                         i_error = 0;
452         }
453         up_read(&EXT3_I(dentry->d_inode)->xattr_sem);
454         return i_error + b_error;
455 }
456
457 /*
458  * If the EXT3_FEATURE_COMPAT_EXT_ATTR feature of this file system is
459  * not set, set it.
460  */
461 static void ext3_xattr_update_super_block(handle_t *handle,
462                                           struct super_block *sb)
463 {
464         if (EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR))
465                 return;
466
467         if (ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh) == 0) {
468                 EXT3_SET_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR);
469                 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
470         }
471 }
472
473 /*
474  * Release the xattr block BH: If the reference count is > 1, decrement
475  * it; otherwise free the block.
476  */
477 static void
478 ext3_xattr_release_block(handle_t *handle, struct inode *inode,
479                          struct buffer_head *bh)
480 {
481         struct mb_cache_entry *ce = NULL;
482         int error = 0;
483
484         ce = mb_cache_entry_get(ext3_xattr_cache, bh->b_bdev, bh->b_blocknr);
485         error = ext3_journal_get_write_access(handle, bh);
486         if (error)
487                  goto out;
488
489         lock_buffer(bh);
490
491         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
492                 ea_bdebug(bh, "refcount now=0; freeing");
493                 if (ce)
494                         mb_cache_entry_free(ce);
495                 ext3_free_blocks(handle, inode, bh->b_blocknr, 1);
496                 get_bh(bh);
497                 ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
498         } else {
499                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
500                 error = ext3_journal_dirty_metadata(handle, bh);
501                 if (IS_SYNC(inode))
502                         handle->h_sync = 1;
503                 dquot_free_block(inode, 1);
504                 ea_bdebug(bh, "refcount now=%d; releasing",
505                           le32_to_cpu(BHDR(bh)->h_refcount));
506                 if (ce)
507                         mb_cache_entry_release(ce);
508         }
509         unlock_buffer(bh);
510 out:
511         ext3_std_error(inode->i_sb, error);
512         return;
513 }
514
515 struct ext3_xattr_info {
516         int name_index;
517         const char *name;
518         const void *value;
519         size_t value_len;
520 };
521
522 struct ext3_xattr_search {
523         struct ext3_xattr_entry *first;
524         void *base;
525         void *end;
526         struct ext3_xattr_entry *here;
527         int not_found;
528 };
529
530 static int
531 ext3_xattr_set_entry(struct ext3_xattr_info *i, struct ext3_xattr_search *s)
532 {
533         struct ext3_xattr_entry *last;
534         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
535
536         /* Compute min_offs and last. */
537         last = s->first;
538         for (; !IS_LAST_ENTRY(last); last = EXT3_XATTR_NEXT(last)) {
539                 if (!last->e_value_block && last->e_value_size) {
540                         size_t offs = le16_to_cpu(last->e_value_offs);
541                         if (offs < min_offs)
542                                 min_offs = offs;
543                 }
544         }
545         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
546         if (!s->not_found) {
547                 if (!s->here->e_value_block && s->here->e_value_size) {
548                         size_t size = le32_to_cpu(s->here->e_value_size);
549                         free += EXT3_XATTR_SIZE(size);
550                 }
551                 free += EXT3_XATTR_LEN(name_len);
552         }
553         if (i->value) {
554                 if (free < EXT3_XATTR_SIZE(i->value_len) ||
555                     free < EXT3_XATTR_LEN(name_len) +
556                            EXT3_XATTR_SIZE(i->value_len))
557                         return -ENOSPC;
558         }
559
560         if (i->value && s->not_found) {
561                 /* Insert the new name. */
562                 size_t size = EXT3_XATTR_LEN(name_len);
563                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
564                 memmove((void *)s->here + size, s->here, rest);
565                 memset(s->here, 0, size);
566                 s->here->e_name_index = i->name_index;
567                 s->here->e_name_len = name_len;
568                 memcpy(s->here->e_name, i->name, name_len);
569         } else {
570                 if (!s->here->e_value_block && s->here->e_value_size) {
571                         void *first_val = s->base + min_offs;
572                         size_t offs = le16_to_cpu(s->here->e_value_offs);
573                         void *val = s->base + offs;
574                         size_t size = EXT3_XATTR_SIZE(
575                                 le32_to_cpu(s->here->e_value_size));
576
577                         if (i->value && size == EXT3_XATTR_SIZE(i->value_len)) {
578                                 /* The old and the new value have the same
579                                    size. Just replace. */
580                                 s->here->e_value_size =
581                                         cpu_to_le32(i->value_len);
582                                 memset(val + size - EXT3_XATTR_PAD, 0,
583                                        EXT3_XATTR_PAD); /* Clear pad bytes. */
584                                 memcpy(val, i->value, i->value_len);
585                                 return 0;
586                         }
587
588                         /* Remove the old value. */
589                         memmove(first_val + size, first_val, val - first_val);
590                         memset(first_val, 0, size);
591                         s->here->e_value_size = 0;
592                         s->here->e_value_offs = 0;
593                         min_offs += size;
594
595                         /* Adjust all value offsets. */
596                         last = s->first;
597                         while (!IS_LAST_ENTRY(last)) {
598                                 size_t o = le16_to_cpu(last->e_value_offs);
599                                 if (!last->e_value_block &&
600                                     last->e_value_size && o < offs)
601                                         last->e_value_offs =
602                                                 cpu_to_le16(o + size);
603                                 last = EXT3_XATTR_NEXT(last);
604                         }
605                 }
606                 if (!i->value) {
607                         /* Remove the old name. */
608                         size_t size = EXT3_XATTR_LEN(name_len);
609                         last = ENTRY((void *)last - size);
610                         memmove(s->here, (void *)s->here + size,
611                                 (void *)last - (void *)s->here + sizeof(__u32));
612                         memset(last, 0, size);
613                 }
614         }
615
616         if (i->value) {
617                 /* Insert the new value. */
618                 s->here->e_value_size = cpu_to_le32(i->value_len);
619                 if (i->value_len) {
620                         size_t size = EXT3_XATTR_SIZE(i->value_len);
621                         void *val = s->base + min_offs - size;
622                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
623                         memset(val + size - EXT3_XATTR_PAD, 0,
624                                EXT3_XATTR_PAD); /* Clear the pad bytes. */
625                         memcpy(val, i->value, i->value_len);
626                 }
627         }
628         return 0;
629 }
630
631 struct ext3_xattr_block_find {
632         struct ext3_xattr_search s;
633         struct buffer_head *bh;
634 };
635
636 static int
637 ext3_xattr_block_find(struct inode *inode, struct ext3_xattr_info *i,
638                       struct ext3_xattr_block_find *bs)
639 {
640         struct super_block *sb = inode->i_sb;
641         int error;
642
643         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
644                   i->name_index, i->name, i->value, (long)i->value_len);
645
646         if (EXT3_I(inode)->i_file_acl) {
647                 /* The inode already has an extended attribute block. */
648                 bs->bh = sb_bread(sb, EXT3_I(inode)->i_file_acl);
649                 error = -EIO;
650                 if (!bs->bh)
651                         goto cleanup;
652                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
653                         atomic_read(&(bs->bh->b_count)),
654                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
655                 if (ext3_xattr_check_block(bs->bh)) {
656                         ext3_error(sb, __func__,
657                                 "inode %lu: bad block "E3FSBLK, inode->i_ino,
658                                 EXT3_I(inode)->i_file_acl);
659                         error = -EIO;
660                         goto cleanup;
661                 }
662                 /* Find the named attribute. */
663                 bs->s.base = BHDR(bs->bh);
664                 bs->s.first = BFIRST(bs->bh);
665                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
666                 bs->s.here = bs->s.first;
667                 error = ext3_xattr_find_entry(&bs->s.here, i->name_index,
668                                               i->name, bs->bh->b_size, 1);
669                 if (error && error != -ENODATA)
670                         goto cleanup;
671                 bs->s.not_found = error;
672         }
673         error = 0;
674
675 cleanup:
676         return error;
677 }
678
679 static int
680 ext3_xattr_block_set(handle_t *handle, struct inode *inode,
681                      struct ext3_xattr_info *i,
682                      struct ext3_xattr_block_find *bs)
683 {
684         struct super_block *sb = inode->i_sb;
685         struct buffer_head *new_bh = NULL;
686         struct ext3_xattr_search *s = &bs->s;
687         struct mb_cache_entry *ce = NULL;
688         int error = 0;
689
690 #define header(x) ((struct ext3_xattr_header *)(x))
691
692         if (i->value && i->value_len > sb->s_blocksize)
693                 return -ENOSPC;
694         if (s->base) {
695                 ce = mb_cache_entry_get(ext3_xattr_cache, bs->bh->b_bdev,
696                                         bs->bh->b_blocknr);
697                 error = ext3_journal_get_write_access(handle, bs->bh);
698                 if (error)
699                         goto cleanup;
700                 lock_buffer(bs->bh);
701
702                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
703                         if (ce) {
704                                 mb_cache_entry_free(ce);
705                                 ce = NULL;
706                         }
707                         ea_bdebug(bs->bh, "modifying in-place");
708                         error = ext3_xattr_set_entry(i, s);
709                         if (!error) {
710                                 if (!IS_LAST_ENTRY(s->first))
711                                         ext3_xattr_rehash(header(s->base),
712                                                           s->here);
713                                 ext3_xattr_cache_insert(bs->bh);
714                         }
715                         unlock_buffer(bs->bh);
716                         if (error == -EIO)
717                                 goto bad_block;
718                         if (!error)
719                                 error = ext3_journal_dirty_metadata(handle,
720                                                                     bs->bh);
721                         if (error)
722                                 goto cleanup;
723                         goto inserted;
724                 } else {
725                         int offset = (char *)s->here - bs->bh->b_data;
726
727                         unlock_buffer(bs->bh);
728                         journal_release_buffer(handle, bs->bh);
729
730                         if (ce) {
731                                 mb_cache_entry_release(ce);
732                                 ce = NULL;
733                         }
734                         ea_bdebug(bs->bh, "cloning");
735                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
736                         error = -ENOMEM;
737                         if (s->base == NULL)
738                                 goto cleanup;
739                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
740                         s->first = ENTRY(header(s->base)+1);
741                         header(s->base)->h_refcount = cpu_to_le32(1);
742                         s->here = ENTRY(s->base + offset);
743                         s->end = s->base + bs->bh->b_size;
744                 }
745         } else {
746                 /* Allocate a buffer where we construct the new block. */
747                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
748                 /* assert(header == s->base) */
749                 error = -ENOMEM;
750                 if (s->base == NULL)
751                         goto cleanup;
752                 header(s->base)->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
753                 header(s->base)->h_blocks = cpu_to_le32(1);
754                 header(s->base)->h_refcount = cpu_to_le32(1);
755                 s->first = ENTRY(header(s->base)+1);
756                 s->here = ENTRY(header(s->base)+1);
757                 s->end = s->base + sb->s_blocksize;
758         }
759
760         error = ext3_xattr_set_entry(i, s);
761         if (error == -EIO)
762                 goto bad_block;
763         if (error)
764                 goto cleanup;
765         if (!IS_LAST_ENTRY(s->first))
766                 ext3_xattr_rehash(header(s->base), s->here);
767
768 inserted:
769         if (!IS_LAST_ENTRY(s->first)) {
770                 new_bh = ext3_xattr_cache_find(inode, header(s->base), &ce);
771                 if (new_bh) {
772                         /* We found an identical block in the cache. */
773                         if (new_bh == bs->bh)
774                                 ea_bdebug(new_bh, "keeping");
775                         else {
776                                 /* The old block is released after updating
777                                    the inode. */
778                                 error = dquot_alloc_block(inode, 1);
779                                 if (error)
780                                         goto cleanup;
781                                 error = ext3_journal_get_write_access(handle,
782                                                                       new_bh);
783                                 if (error)
784                                         goto cleanup_dquot;
785                                 lock_buffer(new_bh);
786                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
787                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
788                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
789                                 unlock_buffer(new_bh);
790                                 error = ext3_journal_dirty_metadata(handle,
791                                                                     new_bh);
792                                 if (error)
793                                         goto cleanup_dquot;
794                         }
795                         mb_cache_entry_release(ce);
796                         ce = NULL;
797                 } else if (bs->bh && s->base == bs->bh->b_data) {
798                         /* We were modifying this block in-place. */
799                         ea_bdebug(bs->bh, "keeping this block");
800                         new_bh = bs->bh;
801                         get_bh(new_bh);
802                 } else {
803                         /* We need to allocate a new block */
804                         ext3_fsblk_t goal = ext3_group_first_block_no(sb,
805                                                 EXT3_I(inode)->i_block_group);
806                         ext3_fsblk_t block = ext3_new_block(handle, inode,
807                                                         goal, &error);
808                         if (error)
809                                 goto cleanup;
810                         ea_idebug(inode, "creating block %d", block);
811
812                         new_bh = sb_getblk(sb, block);
813                         if (!new_bh) {
814 getblk_failed:
815                                 ext3_free_blocks(handle, inode, block, 1);
816                                 error = -EIO;
817                                 goto cleanup;
818                         }
819                         lock_buffer(new_bh);
820                         error = ext3_journal_get_create_access(handle, new_bh);
821                         if (error) {
822                                 unlock_buffer(new_bh);
823                                 goto getblk_failed;
824                         }
825                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
826                         set_buffer_uptodate(new_bh);
827                         unlock_buffer(new_bh);
828                         ext3_xattr_cache_insert(new_bh);
829                         error = ext3_journal_dirty_metadata(handle, new_bh);
830                         if (error)
831                                 goto cleanup;
832                 }
833         }
834
835         /* Update the inode. */
836         EXT3_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
837
838         /* Drop the previous xattr block. */
839         if (bs->bh && bs->bh != new_bh)
840                 ext3_xattr_release_block(handle, inode, bs->bh);
841         error = 0;
842
843 cleanup:
844         if (ce)
845                 mb_cache_entry_release(ce);
846         brelse(new_bh);
847         if (!(bs->bh && s->base == bs->bh->b_data))
848                 kfree(s->base);
849
850         return error;
851
852 cleanup_dquot:
853         dquot_free_block(inode, 1);
854         goto cleanup;
855
856 bad_block:
857         ext3_error(inode->i_sb, __func__,
858                    "inode %lu: bad block "E3FSBLK, inode->i_ino,
859                    EXT3_I(inode)->i_file_acl);
860         goto cleanup;
861
862 #undef header
863 }
864
865 struct ext3_xattr_ibody_find {
866         struct ext3_xattr_search s;
867         struct ext3_iloc iloc;
868 };
869
870 static int
871 ext3_xattr_ibody_find(struct inode *inode, struct ext3_xattr_info *i,
872                       struct ext3_xattr_ibody_find *is)
873 {
874         struct ext3_xattr_ibody_header *header;
875         struct ext3_inode *raw_inode;
876         int error;
877
878         if (EXT3_I(inode)->i_extra_isize == 0)
879                 return 0;
880         raw_inode = ext3_raw_inode(&is->iloc);
881         header = IHDR(inode, raw_inode);
882         is->s.base = is->s.first = IFIRST(header);
883         is->s.here = is->s.first;
884         is->s.end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
885         if (ext3_test_inode_state(inode, EXT3_STATE_XATTR)) {
886                 error = ext3_xattr_check_names(IFIRST(header), is->s.end);
887                 if (error)
888                         return error;
889                 /* Find the named attribute. */
890                 error = ext3_xattr_find_entry(&is->s.here, i->name_index,
891                                               i->name, is->s.end -
892                                               (void *)is->s.base, 0);
893                 if (error && error != -ENODATA)
894                         return error;
895                 is->s.not_found = error;
896         }
897         return 0;
898 }
899
900 static int
901 ext3_xattr_ibody_set(handle_t *handle, struct inode *inode,
902                      struct ext3_xattr_info *i,
903                      struct ext3_xattr_ibody_find *is)
904 {
905         struct ext3_xattr_ibody_header *header;
906         struct ext3_xattr_search *s = &is->s;
907         int error;
908
909         if (EXT3_I(inode)->i_extra_isize == 0)
910                 return -ENOSPC;
911         error = ext3_xattr_set_entry(i, s);
912         if (error)
913                 return error;
914         header = IHDR(inode, ext3_raw_inode(&is->iloc));
915         if (!IS_LAST_ENTRY(s->first)) {
916                 header->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
917                 ext3_set_inode_state(inode, EXT3_STATE_XATTR);
918         } else {
919                 header->h_magic = cpu_to_le32(0);
920                 ext3_clear_inode_state(inode, EXT3_STATE_XATTR);
921         }
922         return 0;
923 }
924
925 /*
926  * ext3_xattr_set_handle()
927  *
928  * Create, replace or remove an extended attribute for this inode. Buffer
929  * is NULL to remove an existing extended attribute, and non-NULL to
930  * either replace an existing extended attribute, or create a new extended
931  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
932  * specify that an extended attribute must exist and must not exist
933  * previous to the call, respectively.
934  *
935  * Returns 0, or a negative error number on failure.
936  */
937 int
938 ext3_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
939                       const char *name, const void *value, size_t value_len,
940                       int flags)
941 {
942         struct ext3_xattr_info i = {
943                 .name_index = name_index,
944                 .name = name,
945                 .value = value,
946                 .value_len = value_len,
947
948         };
949         struct ext3_xattr_ibody_find is = {
950                 .s = { .not_found = -ENODATA, },
951         };
952         struct ext3_xattr_block_find bs = {
953                 .s = { .not_found = -ENODATA, },
954         };
955         int error;
956
957         if (!name)
958                 return -EINVAL;
959         if (strlen(name) > 255)
960                 return -ERANGE;
961         down_write(&EXT3_I(inode)->xattr_sem);
962         error = ext3_get_inode_loc(inode, &is.iloc);
963         if (error)
964                 goto cleanup;
965
966         error = ext3_journal_get_write_access(handle, is.iloc.bh);
967         if (error)
968                 goto cleanup;
969
970         if (ext3_test_inode_state(inode, EXT3_STATE_NEW)) {
971                 struct ext3_inode *raw_inode = ext3_raw_inode(&is.iloc);
972                 memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
973                 ext3_clear_inode_state(inode, EXT3_STATE_NEW);
974         }
975
976         error = ext3_xattr_ibody_find(inode, &i, &is);
977         if (error)
978                 goto cleanup;
979         if (is.s.not_found)
980                 error = ext3_xattr_block_find(inode, &i, &bs);
981         if (error)
982                 goto cleanup;
983         if (is.s.not_found && bs.s.not_found) {
984                 error = -ENODATA;
985                 if (flags & XATTR_REPLACE)
986                         goto cleanup;
987                 error = 0;
988                 if (!value)
989                         goto cleanup;
990         } else {
991                 error = -EEXIST;
992                 if (flags & XATTR_CREATE)
993                         goto cleanup;
994         }
995         if (!value) {
996                 if (!is.s.not_found)
997                         error = ext3_xattr_ibody_set(handle, inode, &i, &is);
998                 else if (!bs.s.not_found)
999                         error = ext3_xattr_block_set(handle, inode, &i, &bs);
1000         } else {
1001                 error = ext3_xattr_ibody_set(handle, inode, &i, &is);
1002                 if (!error && !bs.s.not_found) {
1003                         i.value = NULL;
1004                         error = ext3_xattr_block_set(handle, inode, &i, &bs);
1005                 } else if (error == -ENOSPC) {
1006                         if (EXT3_I(inode)->i_file_acl && !bs.s.base) {
1007                                 error = ext3_xattr_block_find(inode, &i, &bs);
1008                                 if (error)
1009                                         goto cleanup;
1010                         }
1011                         error = ext3_xattr_block_set(handle, inode, &i, &bs);
1012                         if (error)
1013                                 goto cleanup;
1014                         if (!is.s.not_found) {
1015                                 i.value = NULL;
1016                                 error = ext3_xattr_ibody_set(handle, inode, &i,
1017                                                              &is);
1018                         }
1019                 }
1020         }
1021         if (!error) {
1022                 ext3_xattr_update_super_block(handle, inode->i_sb);
1023                 inode->i_ctime = CURRENT_TIME_SEC;
1024                 error = ext3_mark_iloc_dirty(handle, inode, &is.iloc);
1025                 /*
1026                  * The bh is consumed by ext3_mark_iloc_dirty, even with
1027                  * error != 0.
1028                  */
1029                 is.iloc.bh = NULL;
1030                 if (IS_SYNC(inode))
1031                         handle->h_sync = 1;
1032         }
1033
1034 cleanup:
1035         brelse(is.iloc.bh);
1036         brelse(bs.bh);
1037         up_write(&EXT3_I(inode)->xattr_sem);
1038         return error;
1039 }
1040
1041 /*
1042  * ext3_xattr_set()
1043  *
1044  * Like ext3_xattr_set_handle, but start from an inode. This extended
1045  * attribute modification is a filesystem transaction by itself.
1046  *
1047  * Returns 0, or a negative error number on failure.
1048  */
1049 int
1050 ext3_xattr_set(struct inode *inode, int name_index, const char *name,
1051                const void *value, size_t value_len, int flags)
1052 {
1053         handle_t *handle;
1054         int error, retries = 0;
1055
1056 retry:
1057         handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
1058         if (IS_ERR(handle)) {
1059                 error = PTR_ERR(handle);
1060         } else {
1061                 int error2;
1062
1063                 error = ext3_xattr_set_handle(handle, inode, name_index, name,
1064                                               value, value_len, flags);
1065                 error2 = ext3_journal_stop(handle);
1066                 if (error == -ENOSPC &&
1067                     ext3_should_retry_alloc(inode->i_sb, &retries))
1068                         goto retry;
1069                 if (error == 0)
1070                         error = error2;
1071         }
1072
1073         return error;
1074 }
1075
1076 /*
1077  * ext3_xattr_delete_inode()
1078  *
1079  * Free extended attribute resources associated with this inode. This
1080  * is called immediately before an inode is freed. We have exclusive
1081  * access to the inode.
1082  */
1083 void
1084 ext3_xattr_delete_inode(handle_t *handle, struct inode *inode)
1085 {
1086         struct buffer_head *bh = NULL;
1087
1088         if (!EXT3_I(inode)->i_file_acl)
1089                 goto cleanup;
1090         bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
1091         if (!bh) {
1092                 ext3_error(inode->i_sb, __func__,
1093                         "inode %lu: block "E3FSBLK" read error", inode->i_ino,
1094                         EXT3_I(inode)->i_file_acl);
1095                 goto cleanup;
1096         }
1097         if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
1098             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1099                 ext3_error(inode->i_sb, __func__,
1100                         "inode %lu: bad block "E3FSBLK, inode->i_ino,
1101                         EXT3_I(inode)->i_file_acl);
1102                 goto cleanup;
1103         }
1104         ext3_xattr_release_block(handle, inode, bh);
1105         EXT3_I(inode)->i_file_acl = 0;
1106
1107 cleanup:
1108         brelse(bh);
1109 }
1110
1111 /*
1112  * ext3_xattr_put_super()
1113  *
1114  * This is called when a file system is unmounted.
1115  */
1116 void
1117 ext3_xattr_put_super(struct super_block *sb)
1118 {
1119         mb_cache_shrink(sb->s_bdev);
1120 }
1121
1122 /*
1123  * ext3_xattr_cache_insert()
1124  *
1125  * Create a new entry in the extended attribute cache, and insert
1126  * it unless such an entry is already in the cache.
1127  *
1128  * Returns 0, or a negative error number on failure.
1129  */
1130 static void
1131 ext3_xattr_cache_insert(struct buffer_head *bh)
1132 {
1133         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1134         struct mb_cache_entry *ce;
1135         int error;
1136
1137         ce = mb_cache_entry_alloc(ext3_xattr_cache, GFP_NOFS);
1138         if (!ce) {
1139                 ea_bdebug(bh, "out of memory");
1140                 return;
1141         }
1142         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1143         if (error) {
1144                 mb_cache_entry_free(ce);
1145                 if (error == -EBUSY) {
1146                         ea_bdebug(bh, "already in cache");
1147                         error = 0;
1148                 }
1149         } else {
1150                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1151                 mb_cache_entry_release(ce);
1152         }
1153 }
1154
1155 /*
1156  * ext3_xattr_cmp()
1157  *
1158  * Compare two extended attribute blocks for equality.
1159  *
1160  * Returns 0 if the blocks are equal, 1 if they differ, and
1161  * a negative error number on errors.
1162  */
1163 static int
1164 ext3_xattr_cmp(struct ext3_xattr_header *header1,
1165                struct ext3_xattr_header *header2)
1166 {
1167         struct ext3_xattr_entry *entry1, *entry2;
1168
1169         entry1 = ENTRY(header1+1);
1170         entry2 = ENTRY(header2+1);
1171         while (!IS_LAST_ENTRY(entry1)) {
1172                 if (IS_LAST_ENTRY(entry2))
1173                         return 1;
1174                 if (entry1->e_hash != entry2->e_hash ||
1175                     entry1->e_name_index != entry2->e_name_index ||
1176                     entry1->e_name_len != entry2->e_name_len ||
1177                     entry1->e_value_size != entry2->e_value_size ||
1178                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1179                         return 1;
1180                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1181                         return -EIO;
1182                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1183                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1184                            le32_to_cpu(entry1->e_value_size)))
1185                         return 1;
1186
1187                 entry1 = EXT3_XATTR_NEXT(entry1);
1188                 entry2 = EXT3_XATTR_NEXT(entry2);
1189         }
1190         if (!IS_LAST_ENTRY(entry2))
1191                 return 1;
1192         return 0;
1193 }
1194
1195 /*
1196  * ext3_xattr_cache_find()
1197  *
1198  * Find an identical extended attribute block.
1199  *
1200  * Returns a pointer to the block found, or NULL if such a block was
1201  * not found or an error occurred.
1202  */
1203 static struct buffer_head *
1204 ext3_xattr_cache_find(struct inode *inode, struct ext3_xattr_header *header,
1205                       struct mb_cache_entry **pce)
1206 {
1207         __u32 hash = le32_to_cpu(header->h_hash);
1208         struct mb_cache_entry *ce;
1209
1210         if (!header->h_hash)
1211                 return NULL;  /* never share */
1212         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1213 again:
1214         ce = mb_cache_entry_find_first(ext3_xattr_cache, 0,
1215                                        inode->i_sb->s_bdev, hash);
1216         while (ce) {
1217                 struct buffer_head *bh;
1218
1219                 if (IS_ERR(ce)) {
1220                         if (PTR_ERR(ce) == -EAGAIN)
1221                                 goto again;
1222                         break;
1223                 }
1224                 bh = sb_bread(inode->i_sb, ce->e_block);
1225                 if (!bh) {
1226                         ext3_error(inode->i_sb, __func__,
1227                                 "inode %lu: block %lu read error",
1228                                 inode->i_ino, (unsigned long) ce->e_block);
1229                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1230                                 EXT3_XATTR_REFCOUNT_MAX) {
1231                         ea_idebug(inode, "block %lu refcount %d>=%d",
1232                                   (unsigned long) ce->e_block,
1233                                   le32_to_cpu(BHDR(bh)->h_refcount),
1234                                           EXT3_XATTR_REFCOUNT_MAX);
1235                 } else if (ext3_xattr_cmp(header, BHDR(bh)) == 0) {
1236                         *pce = ce;
1237                         return bh;
1238                 }
1239                 brelse(bh);
1240                 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1241         }
1242         return NULL;
1243 }
1244
1245 #define NAME_HASH_SHIFT 5
1246 #define VALUE_HASH_SHIFT 16
1247
1248 /*
1249  * ext3_xattr_hash_entry()
1250  *
1251  * Compute the hash of an extended attribute.
1252  */
1253 static inline void ext3_xattr_hash_entry(struct ext3_xattr_header *header,
1254                                          struct ext3_xattr_entry *entry)
1255 {
1256         __u32 hash = 0;
1257         char *name = entry->e_name;
1258         int n;
1259
1260         for (n=0; n < entry->e_name_len; n++) {
1261                 hash = (hash << NAME_HASH_SHIFT) ^
1262                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1263                        *name++;
1264         }
1265
1266         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1267                 __le32 *value = (__le32 *)((char *)header +
1268                         le16_to_cpu(entry->e_value_offs));
1269                 for (n = (le32_to_cpu(entry->e_value_size) +
1270                      EXT3_XATTR_ROUND) >> EXT3_XATTR_PAD_BITS; n; n--) {
1271                         hash = (hash << VALUE_HASH_SHIFT) ^
1272                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1273                                le32_to_cpu(*value++);
1274                 }
1275         }
1276         entry->e_hash = cpu_to_le32(hash);
1277 }
1278
1279 #undef NAME_HASH_SHIFT
1280 #undef VALUE_HASH_SHIFT
1281
1282 #define BLOCK_HASH_SHIFT 16
1283
1284 /*
1285  * ext3_xattr_rehash()
1286  *
1287  * Re-compute the extended attribute hash value after an entry has changed.
1288  */
1289 static void ext3_xattr_rehash(struct ext3_xattr_header *header,
1290                               struct ext3_xattr_entry *entry)
1291 {
1292         struct ext3_xattr_entry *here;
1293         __u32 hash = 0;
1294
1295         ext3_xattr_hash_entry(header, entry);
1296         here = ENTRY(header+1);
1297         while (!IS_LAST_ENTRY(here)) {
1298                 if (!here->e_hash) {
1299                         /* Block is not shared if an entry's hash value == 0 */
1300                         hash = 0;
1301                         break;
1302                 }
1303                 hash = (hash << BLOCK_HASH_SHIFT) ^
1304                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1305                        le32_to_cpu(here->e_hash);
1306                 here = EXT3_XATTR_NEXT(here);
1307         }
1308         header->h_hash = cpu_to_le32(hash);
1309 }
1310
1311 #undef BLOCK_HASH_SHIFT
1312
1313 int __init
1314 init_ext3_xattr(void)
1315 {
1316         ext3_xattr_cache = mb_cache_create("ext3_xattr", NULL,
1317                 sizeof(struct mb_cache_entry) +
1318                 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1319         if (!ext3_xattr_cache)
1320                 return -ENOMEM;
1321         return 0;
1322 }
1323
1324 void
1325 exit_ext3_xattr(void)
1326 {
1327         if (ext3_xattr_cache)
1328                 mb_cache_destroy(ext3_xattr_cache);
1329         ext3_xattr_cache = NULL;
1330 }