c619a7ea670d1a1aa7d23b403bfb4f6e411725d3
[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 dentry *dentry, 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, 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_test_inode_state(inode, 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 dentry *dentry, 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(dentry, buffer, rest,
339                                                     entry->e_name,
340                                                     entry->e_name_len,
341                                                     handler->flags);
342                         if (buffer) {
343                                 if (size > rest)
344                                         return -ERANGE;
345                                 buffer += size;
346                         }
347                         rest -= size;
348                 }
349         }
350         return buffer_size - rest;
351 }
352
353 static int
354 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
355 {
356         struct inode *inode = dentry->d_inode;
357         struct buffer_head *bh = NULL;
358         int error;
359
360         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
361                   buffer, (long)buffer_size);
362
363         error = 0;
364         if (!EXT4_I(inode)->i_file_acl)
365                 goto cleanup;
366         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
367         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
368         error = -EIO;
369         if (!bh)
370                 goto cleanup;
371         ea_bdebug(bh, "b_count=%d, refcount=%d",
372                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
373         if (ext4_xattr_check_block(bh)) {
374                 ext4_error(inode->i_sb, __func__,
375                            "inode %lu: bad block %llu", inode->i_ino,
376                            EXT4_I(inode)->i_file_acl);
377                 error = -EIO;
378                 goto cleanup;
379         }
380         ext4_xattr_cache_insert(bh);
381         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
382
383 cleanup:
384         brelse(bh);
385
386         return error;
387 }
388
389 static int
390 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
391 {
392         struct inode *inode = dentry->d_inode;
393         struct ext4_xattr_ibody_header *header;
394         struct ext4_inode *raw_inode;
395         struct ext4_iloc iloc;
396         void *end;
397         int error;
398
399         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
400                 return 0;
401         error = ext4_get_inode_loc(inode, &iloc);
402         if (error)
403                 return error;
404         raw_inode = ext4_raw_inode(&iloc);
405         header = IHDR(inode, raw_inode);
406         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
407         error = ext4_xattr_check_names(IFIRST(header), end);
408         if (error)
409                 goto cleanup;
410         error = ext4_xattr_list_entries(dentry, IFIRST(header),
411                                         buffer, buffer_size);
412
413 cleanup:
414         brelse(iloc.bh);
415         return error;
416 }
417
418 /*
419  * ext4_xattr_list()
420  *
421  * Copy a list of attribute names into the buffer
422  * provided, or compute the buffer size required.
423  * Buffer is NULL to compute the size of the buffer required.
424  *
425  * Returns a negative error number on failure, or the number of bytes
426  * used / required on success.
427  */
428 static int
429 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
430 {
431         int i_error, b_error;
432
433         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
434         i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
435         if (i_error < 0) {
436                 b_error = 0;
437         } else {
438                 if (buffer) {
439                         buffer += i_error;
440                         buffer_size -= i_error;
441                 }
442                 b_error = ext4_xattr_block_list(dentry, buffer, buffer_size);
443                 if (b_error < 0)
444                         i_error = 0;
445         }
446         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
447         return i_error + b_error;
448 }
449
450 /*
451  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
452  * not set, set it.
453  */
454 static void ext4_xattr_update_super_block(handle_t *handle,
455                                           struct super_block *sb)
456 {
457         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
458                 return;
459
460         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
461                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
462                 sb->s_dirt = 1;
463                 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
464         }
465 }
466
467 /*
468  * Release the xattr block BH: If the reference count is > 1, decrement
469  * it; otherwise free the block.
470  */
471 static void
472 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
473                          struct buffer_head *bh)
474 {
475         struct mb_cache_entry *ce = NULL;
476         int error = 0;
477
478         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
479         error = ext4_journal_get_write_access(handle, bh);
480         if (error)
481                 goto out;
482
483         lock_buffer(bh);
484         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
485                 ea_bdebug(bh, "refcount now=0; freeing");
486                 if (ce)
487                         mb_cache_entry_free(ce);
488                 get_bh(bh);
489                 ext4_free_blocks(handle, inode, bh, 0, 1,
490                                  EXT4_FREE_BLOCKS_METADATA |
491                                  EXT4_FREE_BLOCKS_FORGET);
492         } else {
493                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
494                 error = ext4_handle_dirty_metadata(handle, inode, bh);
495                 if (IS_SYNC(inode))
496                         ext4_handle_sync(handle);
497                 vfs_dq_free_block(inode, 1);
498                 ea_bdebug(bh, "refcount now=%d; releasing",
499                           le32_to_cpu(BHDR(bh)->h_refcount));
500                 if (ce)
501                         mb_cache_entry_release(ce);
502         }
503         unlock_buffer(bh);
504 out:
505         ext4_std_error(inode->i_sb, error);
506         return;
507 }
508
509 /*
510  * Find the available free space for EAs. This also returns the total number of
511  * bytes used by EA entries.
512  */
513 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
514                                     size_t *min_offs, void *base, int *total)
515 {
516         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
517                 *total += EXT4_XATTR_LEN(last->e_name_len);
518                 if (!last->e_value_block && last->e_value_size) {
519                         size_t offs = le16_to_cpu(last->e_value_offs);
520                         if (offs < *min_offs)
521                                 *min_offs = offs;
522                 }
523         }
524         return (*min_offs - ((void *)last - base) - sizeof(__u32));
525 }
526
527 struct ext4_xattr_info {
528         int name_index;
529         const char *name;
530         const void *value;
531         size_t value_len;
532 };
533
534 struct ext4_xattr_search {
535         struct ext4_xattr_entry *first;
536         void *base;
537         void *end;
538         struct ext4_xattr_entry *here;
539         int not_found;
540 };
541
542 static int
543 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
544 {
545         struct ext4_xattr_entry *last;
546         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
547
548         /* Compute min_offs and last. */
549         last = s->first;
550         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
551                 if (!last->e_value_block && last->e_value_size) {
552                         size_t offs = le16_to_cpu(last->e_value_offs);
553                         if (offs < min_offs)
554                                 min_offs = offs;
555                 }
556         }
557         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
558         if (!s->not_found) {
559                 if (!s->here->e_value_block && s->here->e_value_size) {
560                         size_t size = le32_to_cpu(s->here->e_value_size);
561                         free += EXT4_XATTR_SIZE(size);
562                 }
563                 free += EXT4_XATTR_LEN(name_len);
564         }
565         if (i->value) {
566                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
567                     free < EXT4_XATTR_LEN(name_len) +
568                            EXT4_XATTR_SIZE(i->value_len))
569                         return -ENOSPC;
570         }
571
572         if (i->value && s->not_found) {
573                 /* Insert the new name. */
574                 size_t size = EXT4_XATTR_LEN(name_len);
575                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
576                 memmove((void *)s->here + size, s->here, rest);
577                 memset(s->here, 0, size);
578                 s->here->e_name_index = i->name_index;
579                 s->here->e_name_len = name_len;
580                 memcpy(s->here->e_name, i->name, name_len);
581         } else {
582                 if (!s->here->e_value_block && s->here->e_value_size) {
583                         void *first_val = s->base + min_offs;
584                         size_t offs = le16_to_cpu(s->here->e_value_offs);
585                         void *val = s->base + offs;
586                         size_t size = EXT4_XATTR_SIZE(
587                                 le32_to_cpu(s->here->e_value_size));
588
589                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
590                                 /* The old and the new value have the same
591                                    size. Just replace. */
592                                 s->here->e_value_size =
593                                         cpu_to_le32(i->value_len);
594                                 memset(val + size - EXT4_XATTR_PAD, 0,
595                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
596                                 memcpy(val, i->value, i->value_len);
597                                 return 0;
598                         }
599
600                         /* Remove the old value. */
601                         memmove(first_val + size, first_val, val - first_val);
602                         memset(first_val, 0, size);
603                         s->here->e_value_size = 0;
604                         s->here->e_value_offs = 0;
605                         min_offs += size;
606
607                         /* Adjust all value offsets. */
608                         last = s->first;
609                         while (!IS_LAST_ENTRY(last)) {
610                                 size_t o = le16_to_cpu(last->e_value_offs);
611                                 if (!last->e_value_block &&
612                                     last->e_value_size && o < offs)
613                                         last->e_value_offs =
614                                                 cpu_to_le16(o + size);
615                                 last = EXT4_XATTR_NEXT(last);
616                         }
617                 }
618                 if (!i->value) {
619                         /* Remove the old name. */
620                         size_t size = EXT4_XATTR_LEN(name_len);
621                         last = ENTRY((void *)last - size);
622                         memmove(s->here, (void *)s->here + size,
623                                 (void *)last - (void *)s->here + sizeof(__u32));
624                         memset(last, 0, size);
625                 }
626         }
627
628         if (i->value) {
629                 /* Insert the new value. */
630                 s->here->e_value_size = cpu_to_le32(i->value_len);
631                 if (i->value_len) {
632                         size_t size = EXT4_XATTR_SIZE(i->value_len);
633                         void *val = s->base + min_offs - size;
634                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
635                         memset(val + size - EXT4_XATTR_PAD, 0,
636                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
637                         memcpy(val, i->value, i->value_len);
638                 }
639         }
640         return 0;
641 }
642
643 struct ext4_xattr_block_find {
644         struct ext4_xattr_search s;
645         struct buffer_head *bh;
646 };
647
648 static int
649 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
650                       struct ext4_xattr_block_find *bs)
651 {
652         struct super_block *sb = inode->i_sb;
653         int error;
654
655         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
656                   i->name_index, i->name, i->value, (long)i->value_len);
657
658         if (EXT4_I(inode)->i_file_acl) {
659                 /* The inode already has an extended attribute block. */
660                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
661                 error = -EIO;
662                 if (!bs->bh)
663                         goto cleanup;
664                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
665                         atomic_read(&(bs->bh->b_count)),
666                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
667                 if (ext4_xattr_check_block(bs->bh)) {
668                         ext4_error(sb, __func__,
669                                 "inode %lu: bad block %llu", inode->i_ino,
670                                 EXT4_I(inode)->i_file_acl);
671                         error = -EIO;
672                         goto cleanup;
673                 }
674                 /* Find the named attribute. */
675                 bs->s.base = BHDR(bs->bh);
676                 bs->s.first = BFIRST(bs->bh);
677                 bs->s.end = bs->bh->b_data + bs->bh->b_size;
678                 bs->s.here = bs->s.first;
679                 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
680                                               i->name, bs->bh->b_size, 1);
681                 if (error && error != -ENODATA)
682                         goto cleanup;
683                 bs->s.not_found = error;
684         }
685         error = 0;
686
687 cleanup:
688         return error;
689 }
690
691 static int
692 ext4_xattr_block_set(handle_t *handle, struct inode *inode,
693                      struct ext4_xattr_info *i,
694                      struct ext4_xattr_block_find *bs)
695 {
696         struct super_block *sb = inode->i_sb;
697         struct buffer_head *new_bh = NULL;
698         struct ext4_xattr_search *s = &bs->s;
699         struct mb_cache_entry *ce = NULL;
700         int error = 0;
701
702 #define header(x) ((struct ext4_xattr_header *)(x))
703
704         if (i->value && i->value_len > sb->s_blocksize)
705                 return -ENOSPC;
706         if (s->base) {
707                 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
708                                         bs->bh->b_blocknr);
709                 error = ext4_journal_get_write_access(handle, bs->bh);
710                 if (error)
711                         goto cleanup;
712                 lock_buffer(bs->bh);
713
714                 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
715                         if (ce) {
716                                 mb_cache_entry_free(ce);
717                                 ce = NULL;
718                         }
719                         ea_bdebug(bs->bh, "modifying in-place");
720                         error = ext4_xattr_set_entry(i, s);
721                         if (!error) {
722                                 if (!IS_LAST_ENTRY(s->first))
723                                         ext4_xattr_rehash(header(s->base),
724                                                           s->here);
725                                 ext4_xattr_cache_insert(bs->bh);
726                         }
727                         unlock_buffer(bs->bh);
728                         if (error == -EIO)
729                                 goto bad_block;
730                         if (!error)
731                                 error = ext4_handle_dirty_metadata(handle,
732                                                                    inode,
733                                                                    bs->bh);
734                         if (error)
735                                 goto cleanup;
736                         goto inserted;
737                 } else {
738                         int offset = (char *)s->here - bs->bh->b_data;
739
740                         unlock_buffer(bs->bh);
741                         jbd2_journal_release_buffer(handle, bs->bh);
742                         if (ce) {
743                                 mb_cache_entry_release(ce);
744                                 ce = NULL;
745                         }
746                         ea_bdebug(bs->bh, "cloning");
747                         s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
748                         error = -ENOMEM;
749                         if (s->base == NULL)
750                                 goto cleanup;
751                         memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
752                         s->first = ENTRY(header(s->base)+1);
753                         header(s->base)->h_refcount = cpu_to_le32(1);
754                         s->here = ENTRY(s->base + offset);
755                         s->end = s->base + bs->bh->b_size;
756                 }
757         } else {
758                 /* Allocate a buffer where we construct the new block. */
759                 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
760                 /* assert(header == s->base) */
761                 error = -ENOMEM;
762                 if (s->base == NULL)
763                         goto cleanup;
764                 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
765                 header(s->base)->h_blocks = cpu_to_le32(1);
766                 header(s->base)->h_refcount = cpu_to_le32(1);
767                 s->first = ENTRY(header(s->base)+1);
768                 s->here = ENTRY(header(s->base)+1);
769                 s->end = s->base + sb->s_blocksize;
770         }
771
772         error = ext4_xattr_set_entry(i, s);
773         if (error == -EIO)
774                 goto bad_block;
775         if (error)
776                 goto cleanup;
777         if (!IS_LAST_ENTRY(s->first))
778                 ext4_xattr_rehash(header(s->base), s->here);
779
780 inserted:
781         if (!IS_LAST_ENTRY(s->first)) {
782                 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
783                 if (new_bh) {
784                         /* We found an identical block in the cache. */
785                         if (new_bh == bs->bh)
786                                 ea_bdebug(new_bh, "keeping");
787                         else {
788                                 /* The old block is released after updating
789                                    the inode. */
790                                 error = -EDQUOT;
791                                 if (vfs_dq_alloc_block(inode, 1))
792                                         goto cleanup;
793                                 error = ext4_journal_get_write_access(handle,
794                                                                       new_bh);
795                                 if (error)
796                                         goto cleanup_dquot;
797                                 lock_buffer(new_bh);
798                                 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1);
799                                 ea_bdebug(new_bh, "reusing; refcount now=%d",
800                                         le32_to_cpu(BHDR(new_bh)->h_refcount));
801                                 unlock_buffer(new_bh);
802                                 error = ext4_handle_dirty_metadata(handle,
803                                                                    inode,
804                                                                    new_bh);
805                                 if (error)
806                                         goto cleanup_dquot;
807                         }
808                         mb_cache_entry_release(ce);
809                         ce = NULL;
810                 } else if (bs->bh && s->base == bs->bh->b_data) {
811                         /* We were modifying this block in-place. */
812                         ea_bdebug(bs->bh, "keeping this block");
813                         new_bh = bs->bh;
814                         get_bh(new_bh);
815                 } else {
816                         /* We need to allocate a new block */
817                         ext4_fsblk_t goal, block;
818
819                         goal = ext4_group_first_block_no(sb,
820                                                 EXT4_I(inode)->i_block_group);
821
822                         /* non-extent files can't have physical blocks past 2^32 */
823                         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
824                                 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
825
826                         block = ext4_new_meta_blocks(handle, inode,
827                                                   goal, NULL, &error);
828                         if (error)
829                                 goto cleanup;
830
831                         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
832                                 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
833
834                         ea_idebug(inode, "creating block %d", block);
835
836                         new_bh = sb_getblk(sb, block);
837                         if (!new_bh) {
838 getblk_failed:
839                                 ext4_free_blocks(handle, inode, 0, block, 1,
840                                                  EXT4_FREE_BLOCKS_METADATA);
841                                 error = -EIO;
842                                 goto cleanup;
843                         }
844                         lock_buffer(new_bh);
845                         error = ext4_journal_get_create_access(handle, new_bh);
846                         if (error) {
847                                 unlock_buffer(new_bh);
848                                 goto getblk_failed;
849                         }
850                         memcpy(new_bh->b_data, s->base, new_bh->b_size);
851                         set_buffer_uptodate(new_bh);
852                         unlock_buffer(new_bh);
853                         ext4_xattr_cache_insert(new_bh);
854                         error = ext4_handle_dirty_metadata(handle,
855                                                            inode, new_bh);
856                         if (error)
857                                 goto cleanup;
858                 }
859         }
860
861         /* Update the inode. */
862         EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
863
864         /* Drop the previous xattr block. */
865         if (bs->bh && bs->bh != new_bh)
866                 ext4_xattr_release_block(handle, inode, bs->bh);
867         error = 0;
868
869 cleanup:
870         if (ce)
871                 mb_cache_entry_release(ce);
872         brelse(new_bh);
873         if (!(bs->bh && s->base == bs->bh->b_data))
874                 kfree(s->base);
875
876         return error;
877
878 cleanup_dquot:
879         vfs_dq_free_block(inode, 1);
880         goto cleanup;
881
882 bad_block:
883         ext4_error(inode->i_sb, __func__,
884                    "inode %lu: bad block %llu", inode->i_ino,
885                    EXT4_I(inode)->i_file_acl);
886         goto cleanup;
887
888 #undef header
889 }
890
891 struct ext4_xattr_ibody_find {
892         struct ext4_xattr_search s;
893         struct ext4_iloc iloc;
894 };
895
896 static int
897 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
898                       struct ext4_xattr_ibody_find *is)
899 {
900         struct ext4_xattr_ibody_header *header;
901         struct ext4_inode *raw_inode;
902         int error;
903
904         if (EXT4_I(inode)->i_extra_isize == 0)
905                 return 0;
906         raw_inode = ext4_raw_inode(&is->iloc);
907         header = IHDR(inode, raw_inode);
908         is->s.base = is->s.first = IFIRST(header);
909         is->s.here = is->s.first;
910         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
911         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
912                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
913                 if (error)
914                         return error;
915                 /* Find the named attribute. */
916                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
917                                               i->name, is->s.end -
918                                               (void *)is->s.base, 0);
919                 if (error && error != -ENODATA)
920                         return error;
921                 is->s.not_found = error;
922         }
923         return 0;
924 }
925
926 static int
927 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
928                      struct ext4_xattr_info *i,
929                      struct ext4_xattr_ibody_find *is)
930 {
931         struct ext4_xattr_ibody_header *header;
932         struct ext4_xattr_search *s = &is->s;
933         int error;
934
935         if (EXT4_I(inode)->i_extra_isize == 0)
936                 return -ENOSPC;
937         error = ext4_xattr_set_entry(i, s);
938         if (error)
939                 return error;
940         header = IHDR(inode, ext4_raw_inode(&is->iloc));
941         if (!IS_LAST_ENTRY(s->first)) {
942                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
943                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
944         } else {
945                 header->h_magic = cpu_to_le32(0);
946                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
947         }
948         return 0;
949 }
950
951 /*
952  * ext4_xattr_set_handle()
953  *
954  * Create, replace or remove an extended attribute for this inode. Buffer
955  * is NULL to remove an existing extended attribute, and non-NULL to
956  * either replace an existing extended attribute, or create a new extended
957  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
958  * specify that an extended attribute must exist and must not exist
959  * previous to the call, respectively.
960  *
961  * Returns 0, or a negative error number on failure.
962  */
963 int
964 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
965                       const char *name, const void *value, size_t value_len,
966                       int flags)
967 {
968         struct ext4_xattr_info i = {
969                 .name_index = name_index,
970                 .name = name,
971                 .value = value,
972                 .value_len = value_len,
973
974         };
975         struct ext4_xattr_ibody_find is = {
976                 .s = { .not_found = -ENODATA, },
977         };
978         struct ext4_xattr_block_find bs = {
979                 .s = { .not_found = -ENODATA, },
980         };
981         unsigned long no_expand;
982         int error;
983
984         if (!name)
985                 return -EINVAL;
986         if (strlen(name) > 255)
987                 return -ERANGE;
988         down_write(&EXT4_I(inode)->xattr_sem);
989         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
990         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
991
992         error = ext4_get_inode_loc(inode, &is.iloc);
993         if (error)
994                 goto cleanup;
995
996         error = ext4_journal_get_write_access(handle, is.iloc.bh);
997         if (error)
998                 goto cleanup;
999
1000         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1001                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1002                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1003                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1004         }
1005
1006         error = ext4_xattr_ibody_find(inode, &i, &is);
1007         if (error)
1008                 goto cleanup;
1009         if (is.s.not_found)
1010                 error = ext4_xattr_block_find(inode, &i, &bs);
1011         if (error)
1012                 goto cleanup;
1013         if (is.s.not_found && bs.s.not_found) {
1014                 error = -ENODATA;
1015                 if (flags & XATTR_REPLACE)
1016                         goto cleanup;
1017                 error = 0;
1018                 if (!value)
1019                         goto cleanup;
1020         } else {
1021                 error = -EEXIST;
1022                 if (flags & XATTR_CREATE)
1023                         goto cleanup;
1024         }
1025         if (!value) {
1026                 if (!is.s.not_found)
1027                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1028                 else if (!bs.s.not_found)
1029                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1030         } else {
1031                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1032                 if (!error && !bs.s.not_found) {
1033                         i.value = NULL;
1034                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1035                 } else if (error == -ENOSPC) {
1036                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1037                                 error = ext4_xattr_block_find(inode, &i, &bs);
1038                                 if (error)
1039                                         goto cleanup;
1040                         }
1041                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1042                         if (error)
1043                                 goto cleanup;
1044                         if (!is.s.not_found) {
1045                                 i.value = NULL;
1046                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1047                                                              &is);
1048                         }
1049                 }
1050         }
1051         if (!error) {
1052                 ext4_xattr_update_super_block(handle, inode->i_sb);
1053                 inode->i_ctime = ext4_current_time(inode);
1054                 if (!value)
1055                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1056                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1057                 /*
1058                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1059                  * error != 0.
1060                  */
1061                 is.iloc.bh = NULL;
1062                 if (IS_SYNC(inode))
1063                         ext4_handle_sync(handle);
1064         }
1065
1066 cleanup:
1067         brelse(is.iloc.bh);
1068         brelse(bs.bh);
1069         if (no_expand == 0)
1070                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1071         up_write(&EXT4_I(inode)->xattr_sem);
1072         return error;
1073 }
1074
1075 /*
1076  * ext4_xattr_set()
1077  *
1078  * Like ext4_xattr_set_handle, but start from an inode. This extended
1079  * attribute modification is a filesystem transaction by itself.
1080  *
1081  * Returns 0, or a negative error number on failure.
1082  */
1083 int
1084 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1085                const void *value, size_t value_len, int flags)
1086 {
1087         handle_t *handle;
1088         int error, retries = 0;
1089
1090 retry:
1091         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1092         if (IS_ERR(handle)) {
1093                 error = PTR_ERR(handle);
1094         } else {
1095                 int error2;
1096
1097                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1098                                               value, value_len, flags);
1099                 error2 = ext4_journal_stop(handle);
1100                 if (error == -ENOSPC &&
1101                     ext4_should_retry_alloc(inode->i_sb, &retries))
1102                         goto retry;
1103                 if (error == 0)
1104                         error = error2;
1105         }
1106
1107         return error;
1108 }
1109
1110 /*
1111  * Shift the EA entries in the inode to create space for the increased
1112  * i_extra_isize.
1113  */
1114 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1115                                      int value_offs_shift, void *to,
1116                                      void *from, size_t n, int blocksize)
1117 {
1118         struct ext4_xattr_entry *last = entry;
1119         int new_offs;
1120
1121         /* Adjust the value offsets of the entries */
1122         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1123                 if (!last->e_value_block && last->e_value_size) {
1124                         new_offs = le16_to_cpu(last->e_value_offs) +
1125                                                         value_offs_shift;
1126                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1127                                  > blocksize);
1128                         last->e_value_offs = cpu_to_le16(new_offs);
1129                 }
1130         }
1131         /* Shift the entries by n bytes */
1132         memmove(to, from, n);
1133 }
1134
1135 /*
1136  * Expand an inode by new_extra_isize bytes when EAs are present.
1137  * Returns 0 on success or negative error number on failure.
1138  */
1139 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1140                                struct ext4_inode *raw_inode, handle_t *handle)
1141 {
1142         struct ext4_xattr_ibody_header *header;
1143         struct ext4_xattr_entry *entry, *last, *first;
1144         struct buffer_head *bh = NULL;
1145         struct ext4_xattr_ibody_find *is = NULL;
1146         struct ext4_xattr_block_find *bs = NULL;
1147         char *buffer = NULL, *b_entry_name = NULL;
1148         size_t min_offs, free;
1149         int total_ino, total_blk;
1150         void *base, *start, *end;
1151         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1152         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1153
1154         down_write(&EXT4_I(inode)->xattr_sem);
1155 retry:
1156         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1157                 up_write(&EXT4_I(inode)->xattr_sem);
1158                 return 0;
1159         }
1160
1161         header = IHDR(inode, raw_inode);
1162         entry = IFIRST(header);
1163
1164         /*
1165          * Check if enough free space is available in the inode to shift the
1166          * entries ahead by new_extra_isize.
1167          */
1168
1169         base = start = entry;
1170         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1171         min_offs = end - base;
1172         last = entry;
1173         total_ino = sizeof(struct ext4_xattr_ibody_header);
1174
1175         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1176         if (free >= new_extra_isize) {
1177                 entry = IFIRST(header);
1178                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1179                                 - new_extra_isize, (void *)raw_inode +
1180                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1181                                 (void *)header, total_ino,
1182                                 inode->i_sb->s_blocksize);
1183                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1184                 error = 0;
1185                 goto cleanup;
1186         }
1187
1188         /*
1189          * Enough free space isn't available in the inode, check if
1190          * EA block can hold new_extra_isize bytes.
1191          */
1192         if (EXT4_I(inode)->i_file_acl) {
1193                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1194                 error = -EIO;
1195                 if (!bh)
1196                         goto cleanup;
1197                 if (ext4_xattr_check_block(bh)) {
1198                         ext4_error(inode->i_sb, __func__,
1199                                 "inode %lu: bad block %llu", inode->i_ino,
1200                                 EXT4_I(inode)->i_file_acl);
1201                         error = -EIO;
1202                         goto cleanup;
1203                 }
1204                 base = BHDR(bh);
1205                 first = BFIRST(bh);
1206                 end = bh->b_data + bh->b_size;
1207                 min_offs = end - base;
1208                 free = ext4_xattr_free_space(first, &min_offs, base,
1209                                              &total_blk);
1210                 if (free < new_extra_isize) {
1211                         if (!tried_min_extra_isize && s_min_extra_isize) {
1212                                 tried_min_extra_isize++;
1213                                 new_extra_isize = s_min_extra_isize;
1214                                 brelse(bh);
1215                                 goto retry;
1216                         }
1217                         error = -1;
1218                         goto cleanup;
1219                 }
1220         } else {
1221                 free = inode->i_sb->s_blocksize;
1222         }
1223
1224         while (new_extra_isize > 0) {
1225                 size_t offs, size, entry_size;
1226                 struct ext4_xattr_entry *small_entry = NULL;
1227                 struct ext4_xattr_info i = {
1228                         .value = NULL,
1229                         .value_len = 0,
1230                 };
1231                 unsigned int total_size;  /* EA entry size + value size */
1232                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1233                 unsigned int min_total_size = ~0U;
1234
1235                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1236                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1237                 if (!is || !bs) {
1238                         error = -ENOMEM;
1239                         goto cleanup;
1240                 }
1241
1242                 is->s.not_found = -ENODATA;
1243                 bs->s.not_found = -ENODATA;
1244                 is->iloc.bh = NULL;
1245                 bs->bh = NULL;
1246
1247                 last = IFIRST(header);
1248                 /* Find the entry best suited to be pushed into EA block */
1249                 entry = NULL;
1250                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1251                         total_size =
1252                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1253                                         EXT4_XATTR_LEN(last->e_name_len);
1254                         if (total_size <= free && total_size < min_total_size) {
1255                                 if (total_size < new_extra_isize) {
1256                                         small_entry = last;
1257                                 } else {
1258                                         entry = last;
1259                                         min_total_size = total_size;
1260                                 }
1261                         }
1262                 }
1263
1264                 if (entry == NULL) {
1265                         if (small_entry) {
1266                                 entry = small_entry;
1267                         } else {
1268                                 if (!tried_min_extra_isize &&
1269                                     s_min_extra_isize) {
1270                                         tried_min_extra_isize++;
1271                                         new_extra_isize = s_min_extra_isize;
1272                                         goto retry;
1273                                 }
1274                                 error = -1;
1275                                 goto cleanup;
1276                         }
1277                 }
1278                 offs = le16_to_cpu(entry->e_value_offs);
1279                 size = le32_to_cpu(entry->e_value_size);
1280                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1281                 i.name_index = entry->e_name_index,
1282                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1283                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1284                 if (!buffer || !b_entry_name) {
1285                         error = -ENOMEM;
1286                         goto cleanup;
1287                 }
1288                 /* Save the entry name and the entry value */
1289                 memcpy(buffer, (void *)IFIRST(header) + offs,
1290                        EXT4_XATTR_SIZE(size));
1291                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1292                 b_entry_name[entry->e_name_len] = '\0';
1293                 i.name = b_entry_name;
1294
1295                 error = ext4_get_inode_loc(inode, &is->iloc);
1296                 if (error)
1297                         goto cleanup;
1298
1299                 error = ext4_xattr_ibody_find(inode, &i, is);
1300                 if (error)
1301                         goto cleanup;
1302
1303                 /* Remove the chosen entry from the inode */
1304                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1305
1306                 entry = IFIRST(header);
1307                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1308                         shift_bytes = new_extra_isize;
1309                 else
1310                         shift_bytes = entry_size + size;
1311                 /* Adjust the offsets and shift the remaining entries ahead */
1312                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1313                         shift_bytes, (void *)raw_inode +
1314                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1315                         (void *)header, total_ino - entry_size,
1316                         inode->i_sb->s_blocksize);
1317
1318                 extra_isize += shift_bytes;
1319                 new_extra_isize -= shift_bytes;
1320                 EXT4_I(inode)->i_extra_isize = extra_isize;
1321
1322                 i.name = b_entry_name;
1323                 i.value = buffer;
1324                 i.value_len = size;
1325                 error = ext4_xattr_block_find(inode, &i, bs);
1326                 if (error)
1327                         goto cleanup;
1328
1329                 /* Add entry which was removed from the inode into the block */
1330                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1331                 if (error)
1332                         goto cleanup;
1333                 kfree(b_entry_name);
1334                 kfree(buffer);
1335                 b_entry_name = NULL;
1336                 buffer = NULL;
1337                 brelse(is->iloc.bh);
1338                 kfree(is);
1339                 kfree(bs);
1340         }
1341         brelse(bh);
1342         up_write(&EXT4_I(inode)->xattr_sem);
1343         return 0;
1344
1345 cleanup:
1346         kfree(b_entry_name);
1347         kfree(buffer);
1348         if (is)
1349                 brelse(is->iloc.bh);
1350         kfree(is);
1351         kfree(bs);
1352         brelse(bh);
1353         up_write(&EXT4_I(inode)->xattr_sem);
1354         return error;
1355 }
1356
1357
1358
1359 /*
1360  * ext4_xattr_delete_inode()
1361  *
1362  * Free extended attribute resources associated with this inode. This
1363  * is called immediately before an inode is freed. We have exclusive
1364  * access to the inode.
1365  */
1366 void
1367 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1368 {
1369         struct buffer_head *bh = NULL;
1370
1371         if (!EXT4_I(inode)->i_file_acl)
1372                 goto cleanup;
1373         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1374         if (!bh) {
1375                 ext4_error(inode->i_sb, __func__,
1376                         "inode %lu: block %llu read error", inode->i_ino,
1377                         EXT4_I(inode)->i_file_acl);
1378                 goto cleanup;
1379         }
1380         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1381             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1382                 ext4_error(inode->i_sb, __func__,
1383                         "inode %lu: bad block %llu", inode->i_ino,
1384                         EXT4_I(inode)->i_file_acl);
1385                 goto cleanup;
1386         }
1387         ext4_xattr_release_block(handle, inode, bh);
1388         EXT4_I(inode)->i_file_acl = 0;
1389
1390 cleanup:
1391         brelse(bh);
1392 }
1393
1394 /*
1395  * ext4_xattr_put_super()
1396  *
1397  * This is called when a file system is unmounted.
1398  */
1399 void
1400 ext4_xattr_put_super(struct super_block *sb)
1401 {
1402         mb_cache_shrink(sb->s_bdev);
1403 }
1404
1405 /*
1406  * ext4_xattr_cache_insert()
1407  *
1408  * Create a new entry in the extended attribute cache, and insert
1409  * it unless such an entry is already in the cache.
1410  *
1411  * Returns 0, or a negative error number on failure.
1412  */
1413 static void
1414 ext4_xattr_cache_insert(struct buffer_head *bh)
1415 {
1416         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1417         struct mb_cache_entry *ce;
1418         int error;
1419
1420         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1421         if (!ce) {
1422                 ea_bdebug(bh, "out of memory");
1423                 return;
1424         }
1425         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1426         if (error) {
1427                 mb_cache_entry_free(ce);
1428                 if (error == -EBUSY) {
1429                         ea_bdebug(bh, "already in cache");
1430                         error = 0;
1431                 }
1432         } else {
1433                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1434                 mb_cache_entry_release(ce);
1435         }
1436 }
1437
1438 /*
1439  * ext4_xattr_cmp()
1440  *
1441  * Compare two extended attribute blocks for equality.
1442  *
1443  * Returns 0 if the blocks are equal, 1 if they differ, and
1444  * a negative error number on errors.
1445  */
1446 static int
1447 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1448                struct ext4_xattr_header *header2)
1449 {
1450         struct ext4_xattr_entry *entry1, *entry2;
1451
1452         entry1 = ENTRY(header1+1);
1453         entry2 = ENTRY(header2+1);
1454         while (!IS_LAST_ENTRY(entry1)) {
1455                 if (IS_LAST_ENTRY(entry2))
1456                         return 1;
1457                 if (entry1->e_hash != entry2->e_hash ||
1458                     entry1->e_name_index != entry2->e_name_index ||
1459                     entry1->e_name_len != entry2->e_name_len ||
1460                     entry1->e_value_size != entry2->e_value_size ||
1461                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1462                         return 1;
1463                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1464                         return -EIO;
1465                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1466                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1467                            le32_to_cpu(entry1->e_value_size)))
1468                         return 1;
1469
1470                 entry1 = EXT4_XATTR_NEXT(entry1);
1471                 entry2 = EXT4_XATTR_NEXT(entry2);
1472         }
1473         if (!IS_LAST_ENTRY(entry2))
1474                 return 1;
1475         return 0;
1476 }
1477
1478 /*
1479  * ext4_xattr_cache_find()
1480  *
1481  * Find an identical extended attribute block.
1482  *
1483  * Returns a pointer to the block found, or NULL if such a block was
1484  * not found or an error occurred.
1485  */
1486 static struct buffer_head *
1487 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1488                       struct mb_cache_entry **pce)
1489 {
1490         __u32 hash = le32_to_cpu(header->h_hash);
1491         struct mb_cache_entry *ce;
1492
1493         if (!header->h_hash)
1494                 return NULL;  /* never share */
1495         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1496 again:
1497         ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1498                                        inode->i_sb->s_bdev, hash);
1499         while (ce) {
1500                 struct buffer_head *bh;
1501
1502                 if (IS_ERR(ce)) {
1503                         if (PTR_ERR(ce) == -EAGAIN)
1504                                 goto again;
1505                         break;
1506                 }
1507                 bh = sb_bread(inode->i_sb, ce->e_block);
1508                 if (!bh) {
1509                         ext4_error(inode->i_sb, __func__,
1510                                 "inode %lu: block %lu read error",
1511                                 inode->i_ino, (unsigned long) ce->e_block);
1512                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1513                                 EXT4_XATTR_REFCOUNT_MAX) {
1514                         ea_idebug(inode, "block %lu refcount %d>=%d",
1515                                   (unsigned long) ce->e_block,
1516                                   le32_to_cpu(BHDR(bh)->h_refcount),
1517                                           EXT4_XATTR_REFCOUNT_MAX);
1518                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1519                         *pce = ce;
1520                         return bh;
1521                 }
1522                 brelse(bh);
1523                 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1524         }
1525         return NULL;
1526 }
1527
1528 #define NAME_HASH_SHIFT 5
1529 #define VALUE_HASH_SHIFT 16
1530
1531 /*
1532  * ext4_xattr_hash_entry()
1533  *
1534  * Compute the hash of an extended attribute.
1535  */
1536 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1537                                          struct ext4_xattr_entry *entry)
1538 {
1539         __u32 hash = 0;
1540         char *name = entry->e_name;
1541         int n;
1542
1543         for (n = 0; n < entry->e_name_len; n++) {
1544                 hash = (hash << NAME_HASH_SHIFT) ^
1545                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1546                        *name++;
1547         }
1548
1549         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1550                 __le32 *value = (__le32 *)((char *)header +
1551                         le16_to_cpu(entry->e_value_offs));
1552                 for (n = (le32_to_cpu(entry->e_value_size) +
1553                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1554                         hash = (hash << VALUE_HASH_SHIFT) ^
1555                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1556                                le32_to_cpu(*value++);
1557                 }
1558         }
1559         entry->e_hash = cpu_to_le32(hash);
1560 }
1561
1562 #undef NAME_HASH_SHIFT
1563 #undef VALUE_HASH_SHIFT
1564
1565 #define BLOCK_HASH_SHIFT 16
1566
1567 /*
1568  * ext4_xattr_rehash()
1569  *
1570  * Re-compute the extended attribute hash value after an entry has changed.
1571  */
1572 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1573                               struct ext4_xattr_entry *entry)
1574 {
1575         struct ext4_xattr_entry *here;
1576         __u32 hash = 0;
1577
1578         ext4_xattr_hash_entry(header, entry);
1579         here = ENTRY(header+1);
1580         while (!IS_LAST_ENTRY(here)) {
1581                 if (!here->e_hash) {
1582                         /* Block is not shared if an entry's hash value == 0 */
1583                         hash = 0;
1584                         break;
1585                 }
1586                 hash = (hash << BLOCK_HASH_SHIFT) ^
1587                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1588                        le32_to_cpu(here->e_hash);
1589                 here = EXT4_XATTR_NEXT(here);
1590         }
1591         header->h_hash = cpu_to_le32(hash);
1592 }
1593
1594 #undef BLOCK_HASH_SHIFT
1595
1596 int __init
1597 init_ext4_xattr(void)
1598 {
1599         ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1600                 sizeof(struct mb_cache_entry) +
1601                 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1602         if (!ext4_xattr_cache)
1603                 return -ENOMEM;
1604         return 0;
1605 }
1606
1607 void
1608 exit_ext4_xattr(void)
1609 {
1610         if (ext4_xattr_cache)
1611                 mb_cache_destroy(ext4_xattr_cache);
1612         ext4_xattr_cache = NULL;
1613 }