910bf9a59cb39c6018d7c7f4d31c0bc00ef26749
[linux-2.6.git] / 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_EXT4_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_EXT4_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_EXT4_FS_POSIX_ACL
116         &ext4_xattr_acl_access_handler,
117         &ext4_xattr_acl_default_handler,
118 #endif
119 #ifdef CONFIG_EXT4_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_handle_dirty_metadata(handle, NULL, 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                 get_bh(bh);
486                 ext4_free_blocks(handle, inode, bh, 0, 1,
487                                  EXT4_FREE_BLOCKS_METADATA |
488                                  EXT4_FREE_BLOCKS_FORGET);
489         } else {
490                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
491                 error = ext4_handle_dirty_metadata(handle, inode, bh);
492                 if (IS_SYNC(inode))
493                         ext4_handle_sync(handle);
494                 vfs_dq_free_block(inode, 1);
495                 ea_bdebug(bh, "refcount now=%d; releasing",
496                           le32_to_cpu(BHDR(bh)->h_refcount));
497                 if (ce)
498                         mb_cache_entry_release(ce);
499         }
500         unlock_buffer(bh);
501 out:
502         ext4_std_error(inode->i_sb, error);
503         return;
504 }
505
506 /*
507  * Find the available free space for EAs. This also returns the total number of
508  * bytes used by EA entries.
509  */
510 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
511                                     size_t *min_offs, void *base, int *total)
512 {
513         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
514                 *total += EXT4_XATTR_LEN(last->e_name_len);
515                 if (!last->e_value_block && last->e_value_size) {
516                         size_t offs = le16_to_cpu(last->e_value_offs);
517                         if (offs < *min_offs)
518                                 *min_offs = offs;
519                 }
520         }
521         return (*min_offs - ((void *)last - base) - sizeof(__u32));
522 }
523
524 struct ext4_xattr_info {
525         int name_index;
526         const char *name;
527         const void *value;
528         size_t value_len;
529 };
530
531 struct ext4_xattr_search {
532         struct ext4_xattr_entry *first;
533         void *base;
534         void *end;
535         struct ext4_xattr_entry *here;
536         int not_found;
537 };
538
539 static int
540 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
541 {
542         struct ext4_xattr_entry *last;
543         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
544
545         /* Compute min_offs and last. */
546         last = s->first;
547         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
548                 if (!last->e_value_block && last->e_value_size) {
549                         size_t offs = le16_to_cpu(last->e_value_offs);
550                         if (offs < min_offs)
551                                 min_offs = offs;
552                 }
553         }
554         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
555         if (!s->not_found) {
556                 if (!s->here->e_value_block && s->here->e_value_size) {
557                         size_t size = le32_to_cpu(s->here->e_value_size);
558                         free += EXT4_XATTR_SIZE(size);
559                 }
560                 free += EXT4_XATTR_LEN(name_len);
561         }
562         if (i->value) {
563                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
564                     free < EXT4_XATTR_LEN(name_len) +
565                            EXT4_XATTR_SIZE(i->value_len))
566                         return -ENOSPC;
567         }
568
569         if (i->value && s->not_found) {
570                 /* Insert the new name. */
571                 size_t size = EXT4_XATTR_LEN(name_len);
572                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
573                 memmove((void *)s->here + size, s->here, rest);
574                 memset(s->here, 0, size);
575                 s->here->e_name_index = i->name_index;
576                 s->here->e_name_len = name_len;
577                 memcpy(s->here->e_name, i->name, name_len);
578         } else {
579                 if (!s->here->e_value_block && s->here->e_value_size) {
580                         void *first_val = s->base + min_offs;
581                         size_t offs = le16_to_cpu(s->here->e_value_offs);
582                         void *val = s->base + offs;
583                         size_t size = EXT4_XATTR_SIZE(
584                                 le32_to_cpu(s->here->e_value_size));
585
586                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
587                                 /* The old and the new value have the same
588                                    size. Just replace. */
589                                 s->here->e_value_size =
590                                         cpu_to_le32(i->value_len);
591                                 memset(val + size - EXT4_XATTR_PAD, 0,
592                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
593                                 memcpy(val, i->value, i->value_len);
594                                 return 0;
595                         }
596
597                         /* Remove the old value. */
598                         memmove(first_val + size, first_val, val - first_val);
599                         memset(first_val, 0, size);
600                         s->here->e_value_size = 0;
601                         s->here->e_value_offs = 0;
602                         min_offs += size;
603
604                         /* Adjust all value offsets. */
605                         last = s->first;
606                         while (!IS_LAST_ENTRY(last)) {
607                                 size_t o = le16_to_cpu(last->e_value_offs);
608                                 if (!last->e_value_block &&
609                                     last->e_value_size && o < offs)
610                                         last->e_value_offs =
611                                                 cpu_to_le16(o + size);
612                                 last = EXT4_XATTR_NEXT(last);
613                         }
614                 }
615                 if (!i->value) {
616                         /* Remove the old name. */
617                         size_t size = EXT4_XATTR_LEN(name_len);
618                         last = ENTRY((void *)last - size);
619                         memmove(s->here, (void *)s->here + size,
620                                 (void *)last - (void *)s->here + sizeof(__u32));
621                         memset(last, 0, size);
622                 }
623         }
624
625         if (i->value) {
626                 /* Insert the new value. */
627                 s->here->e_value_size = cpu_to_le32(i->value_len);
628                 if (i->value_len) {
629                         size_t size = EXT4_XATTR_SIZE(i->value_len);
630                         void *val = s->base + min_offs - size;
631                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
632                         memset(val + size - EXT4_XATTR_PAD, 0,
633                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
634                         memcpy(val, i->value, i->value_len);
635                 }
636         }
637         return 0;
638 }
639
640 struct ext4_xattr_block_find {
641         struct ext4_xattr_search s;
642         struct buffer_head *bh;
643 };
644
645 static int
646 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
647                       struct ext4_xattr_block_find *bs)
648 {
649         struct super_block *sb = inode->i_sb;
650         int error;
651
652         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
653                   i->name_index, i->name, i->value, (long)i->value_len);
654
655         if (EXT4_I(inode)->i_file_acl) {
656                 /* The inode already has an extended attribute block. */
657                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
658                 error = -EIO;
659                 if (!bs->bh)
660                         goto cleanup;
661                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
662                         atomic_read(&(bs->bh->b_count)),
663                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
664                 if (ext4_xattr_check_block(bs->bh)) {
665                         ext4_error(sb, __func__,
666                                 "inode %lu: bad block %llu", inode->i_ino,
667                                 EXT4_I(inode)->i_file_acl);
668                         error = -EIO;
669                         goto cleanup;
670                 }
671                 /* Find the named attribute. */
672                 bs->s.base = BHDR(bs->bh);
673                 bs->s.first = BFIRST(bs->bh);
674                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
675                 bs->s.here = bs->s.first;
676                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
677                                               i->name, bs->bh->b_size, 1);
678                 if (error && error != -ENODATA)
679                         goto cleanup;
680                 bs->s.not_found = error;
681         }
682         error = 0;
683
684 cleanup:
685         return error;
686 }
687
688 static int
689 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
690                      struct ext4_xattr_info *i,
691                      struct ext4_xattr_block_find *bs)
692 {
693         struct super_block *sb = inode->i_sb;
694         struct buffer_head *new_bh = NULL;
695         struct ext4_xattr_search *s = &bs->s;
696         struct mb_cache_entry *ce = NULL;
697         int error = 0;
698
699 #define header(x) ((struct ext4_xattr_header *)(x))
700
701         if (i->value && i->value_len > sb->s_blocksize)
702                 return -ENOSPC;
703         if (s->base) {
704                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
705                                         bs->bh->b_blocknr);
706                 error = ext4_journal_get_write_access(handle, bs->bh);
707                 if (error)
708                         goto cleanup;
709                 lock_buffer(bs->bh);
710
711                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
712                         if (ce) {
713                                 mb_cache_entry_free(ce);
714                                 ce = NULL;
715                         }
716                         ea_bdebug(bs->bh, "modifying in-place");
717                         error = ext4_xattr_set_entry(i, s);
718                         if (!error) {
719                                 if (!IS_LAST_ENTRY(s->first))
720                                         ext4_xattr_rehash(header(s->base),
721                                                           s->here);
722                                 ext4_xattr_cache_insert(bs->bh);
723                         }
724                         unlock_buffer(bs->bh);
725                         if (error == -EIO)
726                                 goto bad_block;
727                         if (!error)
728                                 error = ext4_handle_dirty_metadata(handle,
729                                                                    inode,
730                                                                    bs->bh);
731                         if (error)
732                                 goto cleanup;
733                         goto inserted;
734                 } else {
735                         int offset = (char *)s->here - bs->bh->b_data;
736
737                         unlock_buffer(bs->bh);
738                         jbd2_journal_release_buffer(handle, bs->bh);
739                         if (ce) {
740                                 mb_cache_entry_release(ce);
741                                 ce = NULL;
742                         }
743                         ea_bdebug(bs->bh, "cloning");
744                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
745                         error = -ENOMEM;
746                         if (s->base == NULL)
747                                 goto cleanup;
748                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
749                         s->first = ENTRY(header(s->base)+1);
750                         header(s->base)->h_refcount = cpu_to_le32(1);
751                         s->here = ENTRY(s->base + offset);
752                         s->end = s->base + bs->bh->b_size;
753                 }
754         } else {
755                 /* Allocate a buffer where we construct the new block. */
756                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
757                 /* assert(header == s->base) */
758                 error = -ENOMEM;
759                 if (s->base == NULL)
760                         goto cleanup;
761                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
762                 header(s->base)->h_blocks = cpu_to_le32(1);
763                 header(s->base)->h_refcount = cpu_to_le32(1);
764                 s->first = ENTRY(header(s->base)+1);
765                 s->here = ENTRY(header(s->base)+1);
766                 s->end = s->base + sb->s_blocksize;
767         }
768
769         error = ext4_xattr_set_entry(i, s);
770         if (error == -EIO)
771                 goto bad_block;
772         if (error)
773                 goto cleanup;
774         if (!IS_LAST_ENTRY(s->first))
775                 ext4_xattr_rehash(header(s->base), s->here);
776
777 inserted:
778         if (!IS_LAST_ENTRY(s->first)) {
779                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
780                 if (new_bh) {
781                         /* We found an identical block in the cache. */
782                         if (new_bh == bs->bh)
783                                 ea_bdebug(new_bh, "keeping");
784                         else {
785                                 /* The old block is released after updating
786                                    the inode. */
787                                 error = -EDQUOT;
788                                 if (vfs_dq_alloc_block(inode, 1))
789                                         goto cleanup;
790                                 error = ext4_journal_get_write_access(handle,
791                                                                       new_bh);
792                                 if (error)
793                                         goto cleanup_dquot;
794                                 lock_buffer(new_bh);
795                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
796                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
797                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
798                                 unlock_buffer(new_bh);
799                                 error = ext4_handle_dirty_metadata(handle,
800                                                                    inode,
801                                                                    new_bh);
802                                 if (error)
803                                         goto cleanup_dquot;
804                         }
805                         mb_cache_entry_release(ce);
806                         ce = NULL;
807                 } else if (bs->bh && s->base == bs->bh->b_data) {
808                         /* We were modifying this block in-place. */
809                         ea_bdebug(bs->bh, "keeping this block");
810                         new_bh = bs->bh;
811                         get_bh(new_bh);
812                 } else {
813                         /* We need to allocate a new block */
814                         ext4_fsblk_t goal, block;
815
816                         goal = ext4_group_first_block_no(sb,
817                                                 EXT4_I(inode)->i_block_group);
818
819                         /* non-extent files can't have physical blocks past 2^32 */
820                         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
821                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
822
823                         block = ext4_new_meta_blocks(handle, inode,
824                                                   goal, NULL, &error);
825                         if (error)
826                                 goto cleanup;
827
828                         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
829                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
830
831                         ea_idebug(inode, "creating block %d", block);
832
833                         new_bh = sb_getblk(sb, block);
834                         if (!new_bh) {
835 getblk_failed:
836                                 ext4_free_blocks(handle, inode, 0, block, 1,
837                                                  EXT4_FREE_BLOCKS_METADATA);
838                                 error = -EIO;
839                                 goto cleanup;
840                         }
841                         lock_buffer(new_bh);
842                         error = ext4_journal_get_create_access(handle, new_bh);
843                         if (error) {
844                                 unlock_buffer(new_bh);
845                                 goto getblk_failed;
846                         }
847                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
848                         set_buffer_uptodate(new_bh);
849                         unlock_buffer(new_bh);
850                         ext4_xattr_cache_insert(new_bh);
851                         error = ext4_handle_dirty_metadata(handle,
852                                                            inode, new_bh);
853                         if (error)
854                                 goto cleanup;
855                 }
856         }
857
858         /* Update the inode. */
859         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
860
861         /* Drop the previous xattr block. */
862         if (bs->bh && bs->bh != new_bh)
863                 ext4_xattr_release_block(handle, inode, bs->bh);
864         error = 0;
865
866 cleanup:
867         if (ce)
868                 mb_cache_entry_release(ce);
869         brelse(new_bh);
870         if (!(bs->bh && s->base == bs->bh->b_data))
871                 kfree(s->base);
872
873         return error;
874
875 cleanup_dquot:
876         vfs_dq_free_block(inode, 1);
877         goto cleanup;
878
879 bad_block:
880         ext4_error(inode->i_sb, __func__,
881                    "inode %lu: bad block %llu", inode->i_ino,
882                    EXT4_I(inode)->i_file_acl);
883         goto cleanup;
884
885 #undef header
886 }
887
888 struct ext4_xattr_ibody_find {
889         struct ext4_xattr_search s;
890         struct ext4_iloc iloc;
891 };
892
893 static int
894 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
895                       struct ext4_xattr_ibody_find *is)
896 {
897         struct ext4_xattr_ibody_header *header;
898         struct ext4_inode *raw_inode;
899         int error;
900
901         if (EXT4_I(inode)->i_extra_isize == 0)
902                 return 0;
903         raw_inode = ext4_raw_inode(&is->iloc);
904         header = IHDR(inode, raw_inode);
905         is->s.base = is->s.first = IFIRST(header);
906         is->s.here = is->s.first;
907         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
908         if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
909                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
910                 if (error)
911                         return error;
912                 /* Find the named attribute. */
913                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
914                                               i->name, is->s.end -
915                                               (void *)is->s.base, 0);
916                 if (error && error != -ENODATA)
917                         return error;
918                 is->s.not_found = error;
919         }
920         return 0;
921 }
922
923 static int
924 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
925                      struct ext4_xattr_info *i,
926                      struct ext4_xattr_ibody_find *is)
927 {
928         struct ext4_xattr_ibody_header *header;
929         struct ext4_xattr_search *s = &is->s;
930         int error;
931
932         if (EXT4_I(inode)->i_extra_isize == 0)
933                 return -ENOSPC;
934         error = ext4_xattr_set_entry(i, s);
935         if (error)
936                 return error;
937         header = IHDR(inode, ext4_raw_inode(&is->iloc));
938         if (!IS_LAST_ENTRY(s->first)) {
939                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
940                 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
941         } else {
942                 header->h_magic = cpu_to_le32(0);
943                 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
944         }
945         return 0;
946 }
947
948 /*
949  * ext4_xattr_set_handle()
950  *
951  * Create, replace or remove an extended attribute for this inode. Buffer
952  * is NULL to remove an existing extended attribute, and non-NULL to
953  * either replace an existing extended attribute, or create a new extended
954  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
955  * specify that an extended attribute must exist and must not exist
956  * previous to the call, respectively.
957  *
958  * Returns 0, or a negative error number on failure.
959  */
960 int
961 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
962                       const char *name, const void *value, size_t value_len,
963                       int flags)
964 {
965         struct ext4_xattr_info i = {
966                 .name_index = name_index,
967                 .name = name,
968                 .value = value,
969                 .value_len = value_len,
970
971         };
972         struct ext4_xattr_ibody_find is = {
973                 .s = { .not_found = -ENODATA, },
974         };
975         struct ext4_xattr_block_find bs = {
976                 .s = { .not_found = -ENODATA, },
977         };
978         unsigned long no_expand;
979         int error;
980
981         if (!name)
982                 return -EINVAL;
983         if (strlen(name) > 255)
984                 return -ERANGE;
985         down_write(&EXT4_I(inode)->xattr_sem);
986         no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND;
987         EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
988
989         error = ext4_get_inode_loc(inode, &is.iloc);
990         if (error)
991                 goto cleanup;
992
993         error = ext4_journal_get_write_access(handle, is.iloc.bh);
994         if (error)
995                 goto cleanup;
996
997         if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
998                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
999                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1000                 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
1001         }
1002
1003         error = ext4_xattr_ibody_find(inode, &i, &is);
1004         if (error)
1005                 goto cleanup;
1006         if (is.s.not_found)
1007                 error = ext4_xattr_block_find(inode, &i, &bs);
1008         if (error)
1009                 goto cleanup;
1010         if (is.s.not_found && bs.s.not_found) {
1011                 error = -ENODATA;
1012                 if (flags & XATTR_REPLACE)
1013                         goto cleanup;
1014                 error = 0;
1015                 if (!value)
1016                         goto cleanup;
1017         } else {
1018                 error = -EEXIST;
1019                 if (flags & XATTR_CREATE)
1020                         goto cleanup;
1021         }
1022         if (!value) {
1023                 if (!is.s.not_found)
1024                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1025                 else if (!bs.s.not_found)
1026                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1027         } else {
1028                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1029                 if (!error && !bs.s.not_found) {
1030                         i.value = NULL;
1031                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1032                 } else if (error == -ENOSPC) {
1033                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1034                                 error = ext4_xattr_block_find(inode, &i, &bs);
1035                                 if (error)
1036                                         goto cleanup;
1037                         }
1038                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1039                         if (error)
1040                                 goto cleanup;
1041                         if (!is.s.not_found) {
1042                                 i.value = NULL;
1043                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1044                                                              &is);
1045                         }
1046                 }
1047         }
1048         if (!error) {
1049                 ext4_xattr_update_super_block(handle, inode->i_sb);
1050                 inode->i_ctime = ext4_current_time(inode);
1051                 if (!value)
1052                         EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1053                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1054                 /*
1055                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1056                  * error != 0.
1057                  */
1058                 is.iloc.bh = NULL;
1059                 if (IS_SYNC(inode))
1060                         ext4_handle_sync(handle);
1061         }
1062
1063 cleanup:
1064         brelse(is.iloc.bh);
1065         brelse(bs.bh);
1066         if (no_expand == 0)
1067                 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
1068         up_write(&EXT4_I(inode)->xattr_sem);
1069         return error;
1070 }
1071
1072 /*
1073  * ext4_xattr_set()
1074  *
1075  * Like ext4_xattr_set_handle, but start from an inode. This extended
1076  * attribute modification is a filesystem transaction by itself.
1077  *
1078  * Returns 0, or a negative error number on failure.
1079  */
1080 int
1081 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1082                const void *value, size_t value_len, int flags)
1083 {
1084         handle_t *handle;
1085         int error, retries = 0;
1086
1087 retry:
1088         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1089         if (IS_ERR(handle)) {
1090                 error = PTR_ERR(handle);
1091         } else {
1092                 int error2;
1093
1094                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1095                                               value, value_len, flags);
1096                 error2 = ext4_journal_stop(handle);
1097                 if (error == -ENOSPC &&
1098                     ext4_should_retry_alloc(inode->i_sb, &retries))
1099                         goto retry;
1100                 if (error == 0)
1101                         error = error2;
1102         }
1103
1104         return error;
1105 }
1106
1107 /*
1108  * Shift the EA entries in the inode to create space for the increased
1109  * i_extra_isize.
1110  */
1111 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1112                                      int value_offs_shift, void *to,
1113                                      void *from, size_t n, int blocksize)
1114 {
1115         struct ext4_xattr_entry *last = entry;
1116         int new_offs;
1117
1118         /* Adjust the value offsets of the entries */
1119         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1120                 if (!last->e_value_block && last->e_value_size) {
1121                         new_offs = le16_to_cpu(last->e_value_offs) +
1122                                                         value_offs_shift;
1123                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1124                                  > blocksize);
1125                         last->e_value_offs = cpu_to_le16(new_offs);
1126                 }
1127         }
1128         /* Shift the entries by n bytes */
1129         memmove(to, from, n);
1130 }
1131
1132 /*
1133  * Expand an inode by new_extra_isize bytes when EAs are present.
1134  * Returns 0 on success or negative error number on failure.
1135  */
1136 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1137                                struct ext4_inode *raw_inode, handle_t *handle)
1138 {
1139         struct ext4_xattr_ibody_header *header;
1140         struct ext4_xattr_entry *entry, *last, *first;
1141         struct buffer_head *bh = NULL;
1142         struct ext4_xattr_ibody_find *is = NULL;
1143         struct ext4_xattr_block_find *bs = NULL;
1144         char *buffer = NULL, *b_entry_name = NULL;
1145         size_t min_offs, free;
1146         int total_ino, total_blk;
1147         void *base, *start, *end;
1148         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1149         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1150
1151         down_write(&EXT4_I(inode)->xattr_sem);
1152 retry:
1153         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1154                 up_write(&EXT4_I(inode)->xattr_sem);
1155                 return 0;
1156         }
1157
1158         header = IHDR(inode, raw_inode);
1159         entry = IFIRST(header);
1160
1161         /*
1162          * Check if enough free space is available in the inode to shift the
1163          * entries ahead by new_extra_isize.
1164          */
1165
1166         base = start = entry;
1167         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1168         min_offs = end - base;
1169         last = entry;
1170         total_ino = sizeof(struct ext4_xattr_ibody_header);
1171
1172         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1173         if (free >= new_extra_isize) {
1174                 entry = IFIRST(header);
1175                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1176                                 - new_extra_isize, (void *)raw_inode +
1177                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1178                                 (void *)header, total_ino,
1179                                 inode->i_sb->s_blocksize);
1180                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1181                 error = 0;
1182                 goto cleanup;
1183         }
1184
1185         /*
1186          * Enough free space isn't available in the inode, check if
1187          * EA block can hold new_extra_isize bytes.
1188          */
1189         if (EXT4_I(inode)->i_file_acl) {
1190                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1191                 error = -EIO;
1192                 if (!bh)
1193                         goto cleanup;
1194                 if (ext4_xattr_check_block(bh)) {
1195                         ext4_error(inode->i_sb, __func__,
1196                                 "inode %lu: bad block %llu", inode->i_ino,
1197                                 EXT4_I(inode)->i_file_acl);
1198                         error = -EIO;
1199                         goto cleanup;
1200                 }
1201                 base = BHDR(bh);
1202                 first = BFIRST(bh);
1203                 end = bh->b_data + bh->b_size;
1204                 min_offs = end - base;
1205                 free = ext4_xattr_free_space(first, &min_offs, base,
1206                                              &total_blk);
1207                 if (free < new_extra_isize) {
1208                         if (!tried_min_extra_isize && s_min_extra_isize) {
1209                                 tried_min_extra_isize++;
1210                                 new_extra_isize = s_min_extra_isize;
1211                                 brelse(bh);
1212                                 goto retry;
1213                         }
1214                         error = -1;
1215                         goto cleanup;
1216                 }
1217         } else {
1218                 free = inode->i_sb->s_blocksize;
1219         }
1220
1221         while (new_extra_isize > 0) {
1222                 size_t offs, size, entry_size;
1223                 struct ext4_xattr_entry *small_entry = NULL;
1224                 struct ext4_xattr_info i = {
1225                         .value = NULL,
1226                         .value_len = 0,
1227                 };
1228                 unsigned int total_size;  /* EA entry size + value size */
1229                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1230                 unsigned int min_total_size = ~0U;
1231
1232                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1233                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1234                 if (!is || !bs) {
1235                         error = -ENOMEM;
1236                         goto cleanup;
1237                 }
1238
1239                 is->s.not_found = -ENODATA;
1240                 bs->s.not_found = -ENODATA;
1241                 is->iloc.bh = NULL;
1242                 bs->bh = NULL;
1243
1244                 last = IFIRST(header);
1245                 /* Find the entry best suited to be pushed into EA block */
1246                 entry = NULL;
1247                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1248                         total_size =
1249                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1250                                         EXT4_XATTR_LEN(last->e_name_len);
1251                         if (total_size <= free && total_size < min_total_size) {
1252                                 if (total_size < new_extra_isize) {
1253                                         small_entry = last;
1254                                 } else {
1255                                         entry = last;
1256                                         min_total_size = total_size;
1257                                 }
1258                         }
1259                 }
1260
1261                 if (entry == NULL) {
1262                         if (small_entry) {
1263                                 entry = small_entry;
1264                         } else {
1265                                 if (!tried_min_extra_isize &&
1266                                     s_min_extra_isize) {
1267                                         tried_min_extra_isize++;
1268                                         new_extra_isize = s_min_extra_isize;
1269                                         goto retry;
1270                                 }
1271                                 error = -1;
1272                                 goto cleanup;
1273                         }
1274                 }
1275                 offs = le16_to_cpu(entry->e_value_offs);
1276                 size = le32_to_cpu(entry->e_value_size);
1277                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1278                 i.name_index = entry->e_name_index,
1279                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1280                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1281                 if (!buffer || !b_entry_name) {
1282                         error = -ENOMEM;
1283                         goto cleanup;
1284                 }
1285                 /* Save the entry name and the entry value */
1286                 memcpy(buffer, (void *)IFIRST(header) + offs,
1287                        EXT4_XATTR_SIZE(size));
1288                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1289                 b_entry_name[entry->e_name_len] = '\0';
1290                 i.name = b_entry_name;
1291
1292                 error = ext4_get_inode_loc(inode, &is->iloc);
1293                 if (error)
1294                         goto cleanup;
1295
1296                 error = ext4_xattr_ibody_find(inode, &i, is);
1297                 if (error)
1298                         goto cleanup;
1299
1300                 /* Remove the chosen entry from the inode */
1301                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1302
1303                 entry = IFIRST(header);
1304                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1305                         shift_bytes = new_extra_isize;
1306                 else
1307                         shift_bytes = entry_size + size;
1308                 /* Adjust the offsets and shift the remaining entries ahead */
1309                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1310                         shift_bytes, (void *)raw_inode +
1311                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1312                         (void *)header, total_ino - entry_size,
1313                         inode->i_sb->s_blocksize);
1314
1315                 extra_isize += shift_bytes;
1316                 new_extra_isize -= shift_bytes;
1317                 EXT4_I(inode)->i_extra_isize = extra_isize;
1318
1319                 i.name = b_entry_name;
1320                 i.value = buffer;
1321                 i.value_len = size;
1322                 error = ext4_xattr_block_find(inode, &i, bs);
1323                 if (error)
1324                         goto cleanup;
1325
1326                 /* Add entry which was removed from the inode into the block */
1327                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1328                 if (error)
1329                         goto cleanup;
1330                 kfree(b_entry_name);
1331                 kfree(buffer);
1332                 brelse(is->iloc.bh);
1333                 kfree(is);
1334                 kfree(bs);
1335         }
1336         brelse(bh);
1337         up_write(&EXT4_I(inode)->xattr_sem);
1338         return 0;
1339
1340 cleanup:
1341         kfree(b_entry_name);
1342         kfree(buffer);
1343         if (is)
1344                 brelse(is->iloc.bh);
1345         kfree(is);
1346         kfree(bs);
1347         brelse(bh);
1348         up_write(&EXT4_I(inode)->xattr_sem);
1349         return error;
1350 }
1351
1352
1353
1354 /*
1355  * ext4_xattr_delete_inode()
1356  *
1357  * Free extended attribute resources associated with this inode. This
1358  * is called immediately before an inode is freed. We have exclusive
1359  * access to the inode.
1360  */
1361 void
1362 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1363 {
1364         struct buffer_head *bh = NULL;
1365
1366         if (!EXT4_I(inode)->i_file_acl)
1367                 goto cleanup;
1368         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1369         if (!bh) {
1370                 ext4_error(inode->i_sb, __func__,
1371                         "inode %lu: block %llu read error", inode->i_ino,
1372                         EXT4_I(inode)->i_file_acl);
1373                 goto cleanup;
1374         }
1375         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1376             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1377                 ext4_error(inode->i_sb, __func__,
1378                         "inode %lu: bad block %llu", inode->i_ino,
1379                         EXT4_I(inode)->i_file_acl);
1380                 goto cleanup;
1381         }
1382         ext4_xattr_release_block(handle, inode, bh);
1383         EXT4_I(inode)->i_file_acl = 0;
1384
1385 cleanup:
1386         brelse(bh);
1387 }
1388
1389 /*
1390  * ext4_xattr_put_super()
1391  *
1392  * This is called when a file system is unmounted.
1393  */
1394 void
1395 ext4_xattr_put_super(struct super_block *sb)
1396 {
1397         mb_cache_shrink(sb->s_bdev);
1398 }
1399
1400 /*
1401  * ext4_xattr_cache_insert()
1402  *
1403  * Create a new entry in the extended attribute cache, and insert
1404  * it unless such an entry is already in the cache.
1405  *
1406  * Returns 0, or a negative error number on failure.
1407  */
1408 static void
1409 ext4_xattr_cache_insert(struct buffer_head *bh)
1410 {
1411         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1412         struct mb_cache_entry *ce;
1413         int error;
1414
1415         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1416         if (!ce) {
1417                 ea_bdebug(bh, "out of memory");
1418                 return;
1419         }
1420         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1421         if (error) {
1422                 mb_cache_entry_free(ce);
1423                 if (error == -EBUSY) {
1424                         ea_bdebug(bh, "already in cache");
1425                         error = 0;
1426                 }
1427         } else {
1428                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1429                 mb_cache_entry_release(ce);
1430         }
1431 }
1432
1433 /*
1434  * ext4_xattr_cmp()
1435  *
1436  * Compare two extended attribute blocks for equality.
1437  *
1438  * Returns 0 if the blocks are equal, 1 if they differ, and
1439  * a negative error number on errors.
1440  */
1441 static int
1442 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1443                struct ext4_xattr_header *header2)
1444 {
1445         struct ext4_xattr_entry *entry1, *entry2;
1446
1447         entry1 = ENTRY(header1+1);
1448         entry2 = ENTRY(header2+1);
1449         while (!IS_LAST_ENTRY(entry1)) {
1450                 if (IS_LAST_ENTRY(entry2))
1451                         return 1;
1452                 if (entry1->e_hash != entry2->e_hash ||
1453                     entry1->e_name_index != entry2->e_name_index ||
1454                     entry1->e_name_len != entry2->e_name_len ||
1455                     entry1->e_value_size != entry2->e_value_size ||
1456                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1457                         return 1;
1458                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1459                         return -EIO;
1460                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1461                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1462                            le32_to_cpu(entry1->e_value_size)))
1463                         return 1;
1464
1465                 entry1 = EXT4_XATTR_NEXT(entry1);
1466                 entry2 = EXT4_XATTR_NEXT(entry2);
1467         }
1468         if (!IS_LAST_ENTRY(entry2))
1469                 return 1;
1470         return 0;
1471 }
1472
1473 /*
1474  * ext4_xattr_cache_find()
1475  *
1476  * Find an identical extended attribute block.
1477  *
1478  * Returns a pointer to the block found, or NULL if such a block was
1479  * not found or an error occurred.
1480  */
1481 static struct buffer_head *
1482 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1483                       struct mb_cache_entry **pce)
1484 {
1485         __u32 hash = le32_to_cpu(header->h_hash);
1486         struct mb_cache_entry *ce;
1487
1488         if (!header->h_hash)
1489                 return NULL;  /* never share */
1490         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1491 again:
1492         ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1493                                        inode->i_sb->s_bdev, hash);
1494         while (ce) {
1495                 struct buffer_head *bh;
1496
1497                 if (IS_ERR(ce)) {
1498                         if (PTR_ERR(ce) == -EAGAIN)
1499                                 goto again;
1500                         break;
1501                 }
1502                 bh = sb_bread(inode->i_sb, ce->e_block);
1503                 if (!bh) {
1504                         ext4_error(inode->i_sb, __func__,
1505                                 "inode %lu: block %lu read error",
1506                                 inode->i_ino, (unsigned long) ce->e_block);
1507                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1508                                 EXT4_XATTR_REFCOUNT_MAX) {
1509                         ea_idebug(inode, "block %lu refcount %d>=%d",
1510                                   (unsigned long) ce->e_block,
1511                                   le32_to_cpu(BHDR(bh)->h_refcount),
1512                                           EXT4_XATTR_REFCOUNT_MAX);
1513                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1514                         *pce = ce;
1515                         return bh;
1516                 }
1517                 brelse(bh);
1518                 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1519         }
1520         return NULL;
1521 }
1522
1523 #define NAME_HASH_SHIFT 5
1524 #define VALUE_HASH_SHIFT 16
1525
1526 /*
1527  * ext4_xattr_hash_entry()
1528  *
1529  * Compute the hash of an extended attribute.
1530  */
1531 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1532                                          struct ext4_xattr_entry *entry)
1533 {
1534         __u32 hash = 0;
1535         char *name = entry->e_name;
1536         int n;
1537
1538         for (n = 0; n < entry->e_name_len; n++) {
1539                 hash = (hash << NAME_HASH_SHIFT) ^
1540                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1541                        *name++;
1542         }
1543
1544         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1545                 __le32 *value = (__le32 *)((char *)header +
1546                         le16_to_cpu(entry->e_value_offs));
1547                 for (n = (le32_to_cpu(entry->e_value_size) +
1548                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1549                         hash = (hash << VALUE_HASH_SHIFT) ^
1550                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1551                                le32_to_cpu(*value++);
1552                 }
1553         }
1554         entry->e_hash = cpu_to_le32(hash);
1555 }
1556
1557 #undef NAME_HASH_SHIFT
1558 #undef VALUE_HASH_SHIFT
1559
1560 #define BLOCK_HASH_SHIFT 16
1561
1562 /*
1563  * ext4_xattr_rehash()
1564  *
1565  * Re-compute the extended attribute hash value after an entry has changed.
1566  */
1567 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1568                               struct ext4_xattr_entry *entry)
1569 {
1570         struct ext4_xattr_entry *here;
1571         __u32 hash = 0;
1572
1573         ext4_xattr_hash_entry(header, entry);
1574         here = ENTRY(header+1);
1575         while (!IS_LAST_ENTRY(here)) {
1576                 if (!here->e_hash) {
1577                         /* Block is not shared if an entry's hash value == 0 */
1578                         hash = 0;
1579                         break;
1580                 }
1581                 hash = (hash << BLOCK_HASH_SHIFT) ^
1582                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1583                        le32_to_cpu(here->e_hash);
1584                 here = EXT4_XATTR_NEXT(here);
1585         }
1586         header->h_hash = cpu_to_le32(hash);
1587 }
1588
1589 #undef BLOCK_HASH_SHIFT
1590
1591 int __init
1592 init_ext4_xattr(void)
1593 {
1594         ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1595                 sizeof(struct mb_cache_entry) +
1596                 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1597         if (!ext4_xattr_cache)
1598                 return -ENOMEM;
1599         return 0;
1600 }
1601
1602 void
1603 exit_ext4_xattr(void)
1604 {
1605         if (ext4_xattr_cache)
1606                 mb_cache_destroy(ext4_xattr_cache);
1607         ext4_xattr_cache = NULL;
1608 }