ext4: move __func__ into a macro for ext4_warning, ext4_error
[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:
231                 ext4_error(inode->i_sb,
232                            "inode %lu: bad block %llu", inode->i_ino,
233                            EXT4_I(inode)->i_file_acl);
234                 error = -EIO;
235                 goto cleanup;
236         }
237         ext4_xattr_cache_insert(bh);
238         entry = BFIRST(bh);
239         error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
240         if (error == -EIO)
241                 goto bad_block;
242         if (error)
243                 goto cleanup;
244         size = le32_to_cpu(entry->e_value_size);
245         if (buffer) {
246                 error = -ERANGE;
247                 if (size > buffer_size)
248                         goto cleanup;
249                 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
250                        size);
251         }
252         error = size;
253
254 cleanup:
255         brelse(bh);
256         return error;
257 }
258
259 static int
260 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
261                      void *buffer, size_t buffer_size)
262 {
263         struct ext4_xattr_ibody_header *header;
264         struct ext4_xattr_entry *entry;
265         struct ext4_inode *raw_inode;
266         struct ext4_iloc iloc;
267         size_t size;
268         void *end;
269         int error;
270
271         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
272                 return -ENODATA;
273         error = ext4_get_inode_loc(inode, &iloc);
274         if (error)
275                 return error;
276         raw_inode = ext4_raw_inode(&iloc);
277         header = IHDR(inode, raw_inode);
278         entry = IFIRST(header);
279         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
280         error = ext4_xattr_check_names(entry, end);
281         if (error)
282                 goto cleanup;
283         error = ext4_xattr_find_entry(&entry, name_index, name,
284                                       end - (void *)entry, 0);
285         if (error)
286                 goto cleanup;
287         size = le32_to_cpu(entry->e_value_size);
288         if (buffer) {
289                 error = -ERANGE;
290                 if (size > buffer_size)
291                         goto cleanup;
292                 memcpy(buffer, (void *)IFIRST(header) +
293                        le16_to_cpu(entry->e_value_offs), size);
294         }
295         error = size;
296
297 cleanup:
298         brelse(iloc.bh);
299         return error;
300 }
301
302 /*
303  * ext4_xattr_get()
304  *
305  * Copy an extended attribute into the buffer
306  * provided, or compute the buffer size required.
307  * Buffer is NULL to compute the size of the buffer required.
308  *
309  * Returns a negative error number on failure, or the number of bytes
310  * used / required on success.
311  */
312 int
313 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
314                void *buffer, size_t buffer_size)
315 {
316         int error;
317
318         down_read(&EXT4_I(inode)->xattr_sem);
319         error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
320                                      buffer_size);
321         if (error == -ENODATA)
322                 error = ext4_xattr_block_get(inode, name_index, name, buffer,
323                                              buffer_size);
324         up_read(&EXT4_I(inode)->xattr_sem);
325         return error;
326 }
327
328 static int
329 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
330                         char *buffer, size_t buffer_size)
331 {
332         size_t rest = buffer_size;
333
334         for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
335                 struct xattr_handler *handler =
336                         ext4_xattr_handler(entry->e_name_index);
337
338                 if (handler) {
339                         size_t size = handler->list(dentry, buffer, rest,
340                                                     entry->e_name,
341                                                     entry->e_name_len,
342                                                     handler->flags);
343                         if (buffer) {
344                                 if (size > rest)
345                                         return -ERANGE;
346                                 buffer += size;
347                         }
348                         rest -= size;
349                 }
350         }
351         return buffer_size - rest;
352 }
353
354 static int
355 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
356 {
357         struct inode *inode = dentry->d_inode;
358         struct buffer_head *bh = NULL;
359         int error;
360
361         ea_idebug(inode, "buffer=%p, buffer_size=%ld",
362                   buffer, (long)buffer_size);
363
364         error = 0;
365         if (!EXT4_I(inode)->i_file_acl)
366                 goto cleanup;
367         ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
368         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
369         error = -EIO;
370         if (!bh)
371                 goto cleanup;
372         ea_bdebug(bh, "b_count=%d, refcount=%d",
373                 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
374         if (ext4_xattr_check_block(bh)) {
375                 ext4_error(inode->i_sb,
376                            "inode %lu: bad block %llu", inode->i_ino,
377                            EXT4_I(inode)->i_file_acl);
378                 error = -EIO;
379                 goto cleanup;
380         }
381         ext4_xattr_cache_insert(bh);
382         error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
383
384 cleanup:
385         brelse(bh);
386
387         return error;
388 }
389
390 static int
391 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
392 {
393         struct inode *inode = dentry->d_inode;
394         struct ext4_xattr_ibody_header *header;
395         struct ext4_inode *raw_inode;
396         struct ext4_iloc iloc;
397         void *end;
398         int error;
399
400         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
401                 return 0;
402         error = ext4_get_inode_loc(inode, &iloc);
403         if (error)
404                 return error;
405         raw_inode = ext4_raw_inode(&iloc);
406         header = IHDR(inode, raw_inode);
407         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
408         error = ext4_xattr_check_names(IFIRST(header), end);
409         if (error)
410                 goto cleanup;
411         error = ext4_xattr_list_entries(dentry, IFIRST(header),
412                                         buffer, buffer_size);
413
414 cleanup:
415         brelse(iloc.bh);
416         return error;
417 }
418
419 /*
420  * ext4_xattr_list()
421  *
422  * Copy a list of attribute names into the buffer
423  * provided, or compute the buffer size required.
424  * Buffer is NULL to compute the size of the buffer required.
425  *
426  * Returns a negative error number on failure, or the number of bytes
427  * used / required on success.
428  */
429 static int
430 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
431 {
432         int i_error, b_error;
433
434         down_read(&EXT4_I(dentry->d_inode)->xattr_sem);
435         i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
436         if (i_error < 0) {
437                 b_error = 0;
438         } else {
439                 if (buffer) {
440                         buffer += i_error;
441                         buffer_size -= i_error;
442                 }
443                 b_error = ext4_xattr_block_list(dentry, buffer, buffer_size);
444                 if (b_error < 0)
445                         i_error = 0;
446         }
447         up_read(&EXT4_I(dentry->d_inode)->xattr_sem);
448         return i_error + b_error;
449 }
450
451 /*
452  * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
453  * not set, set it.
454  */
455 static void ext4_xattr_update_super_block(handle_t *handle,
456                                           struct super_block *sb)
457 {
458         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
459                 return;
460
461         if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
462                 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
463                 sb->s_dirt = 1;
464                 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
465         }
466 }
467
468 /*
469  * Release the xattr block BH: If the reference count is > 1, decrement
470  * it; otherwise free the block.
471  */
472 static void
473 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
474                          struct buffer_head *bh)
475 {
476         struct mb_cache_entry *ce = NULL;
477         int error = 0;
478
479         ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
480         error = ext4_journal_get_write_access(handle, bh);
481         if (error)
482                 goto out;
483
484         lock_buffer(bh);
485         if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
486                 ea_bdebug(bh, "refcount now=0; freeing");
487                 if (ce)
488                         mb_cache_entry_free(ce);
489                 get_bh(bh);
490                 ext4_free_blocks(handle, inode, bh, 0, 1,
491                                  EXT4_FREE_BLOCKS_METADATA |
492                                  EXT4_FREE_BLOCKS_FORGET);
493         } else {
494                 le32_add_cpu(&BHDR(bh)->h_refcount, -1);
495                 error = ext4_handle_dirty_metadata(handle, inode, bh);
496                 if (IS_SYNC(inode))
497                         ext4_handle_sync(handle);
498                 vfs_dq_free_block(inode, 1);
499                 ea_bdebug(bh, "refcount now=%d; releasing",
500                           le32_to_cpu(BHDR(bh)->h_refcount));
501                 if (ce)
502                         mb_cache_entry_release(ce);
503         }
504         unlock_buffer(bh);
505 out:
506         ext4_std_error(inode->i_sb, error);
507         return;
508 }
509
510 /*
511  * Find the available free space for EAs. This also returns the total number of
512  * bytes used by EA entries.
513  */
514 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
515                                     size_t *min_offs, void *base, int *total)
516 {
517         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
518                 *total += EXT4_XATTR_LEN(last->e_name_len);
519                 if (!last->e_value_block && last->e_value_size) {
520                         size_t offs = le16_to_cpu(last->e_value_offs);
521                         if (offs < *min_offs)
522                                 *min_offs = offs;
523                 }
524         }
525         return (*min_offs - ((void *)last - base) - sizeof(__u32));
526 }
527
528 struct ext4_xattr_info {
529         int name_index;
530         const char *name;
531         const void *value;
532         size_t value_len;
533 };
534
535 struct ext4_xattr_search {
536         struct ext4_xattr_entry *first;
537         void *base;
538         void *end;
539         struct ext4_xattr_entry *here;
540         int not_found;
541 };
542
543 static int
544 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
545 {
546         struct ext4_xattr_entry *last;
547         size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
548
549         /* Compute min_offs and last. */
550         last = s->first;
551         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
552                 if (!last->e_value_block && last->e_value_size) {
553                         size_t offs = le16_to_cpu(last->e_value_offs);
554                         if (offs < min_offs)
555                                 min_offs = offs;
556                 }
557         }
558         free = min_offs - ((void *)last - s->base) - sizeof(__u32);
559         if (!s->not_found) {
560                 if (!s->here->e_value_block && s->here->e_value_size) {
561                         size_t size = le32_to_cpu(s->here->e_value_size);
562                         free += EXT4_XATTR_SIZE(size);
563                 }
564                 free += EXT4_XATTR_LEN(name_len);
565         }
566         if (i->value) {
567                 if (free < EXT4_XATTR_SIZE(i->value_len) ||
568                     free < EXT4_XATTR_LEN(name_len) +
569                            EXT4_XATTR_SIZE(i->value_len))
570                         return -ENOSPC;
571         }
572
573         if (i->value && s->not_found) {
574                 /* Insert the new name. */
575                 size_t size = EXT4_XATTR_LEN(name_len);
576                 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
577                 memmove((void *)s->here + size, s->here, rest);
578                 memset(s->here, 0, size);
579                 s->here->e_name_index = i->name_index;
580                 s->here->e_name_len = name_len;
581                 memcpy(s->here->e_name, i->name, name_len);
582         } else {
583                 if (!s->here->e_value_block && s->here->e_value_size) {
584                         void *first_val = s->base + min_offs;
585                         size_t offs = le16_to_cpu(s->here->e_value_offs);
586                         void *val = s->base + offs;
587                         size_t size = EXT4_XATTR_SIZE(
588                                 le32_to_cpu(s->here->e_value_size));
589
590                         if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
591                                 /* The old and the new value have the same
592                                    size. Just replace. */
593                                 s->here->e_value_size =
594                                         cpu_to_le32(i->value_len);
595                                 memset(val + size - EXT4_XATTR_PAD, 0,
596                                        EXT4_XATTR_PAD); /* Clear pad bytes. */
597                                 memcpy(val, i->value, i->value_len);
598                                 return 0;
599                         }
600
601                         /* Remove the old value. */
602                         memmove(first_val + size, first_val, val - first_val);
603                         memset(first_val, 0, size);
604                         s->here->e_value_size = 0;
605                         s->here->e_value_offs = 0;
606                         min_offs += size;
607
608                         /* Adjust all value offsets. */
609                         last = s->first;
610                         while (!IS_LAST_ENTRY(last)) {
611                                 size_t o = le16_to_cpu(last->e_value_offs);
612                                 if (!last->e_value_block &&
613                                     last->e_value_size && o < offs)
614                                         last->e_value_offs =
615                                                 cpu_to_le16(o + size);
616                                 last = EXT4_XATTR_NEXT(last);
617                         }
618                 }
619                 if (!i->value) {
620                         /* Remove the old name. */
621                         size_t size = EXT4_XATTR_LEN(name_len);
622                         last = ENTRY((void *)last - size);
623                         memmove(s->here, (void *)s->here + size,
624                                 (void *)last - (void *)s->here + sizeof(__u32));
625                         memset(last, 0, size);
626                 }
627         }
628
629         if (i->value) {
630                 /* Insert the new value. */
631                 s->here->e_value_size = cpu_to_le32(i->value_len);
632                 if (i->value_len) {
633                         size_t size = EXT4_XATTR_SIZE(i->value_len);
634                         void *val = s->base + min_offs - size;
635                         s->here->e_value_offs = cpu_to_le16(min_offs - size);
636                         memset(val + size - EXT4_XATTR_PAD, 0,
637                                EXT4_XATTR_PAD); /* Clear the pad bytes. */
638                         memcpy(val, i->value, i->value_len);
639                 }
640         }
641         return 0;
642 }
643
644 struct ext4_xattr_block_find {
645         struct ext4_xattr_search s;
646         struct buffer_head *bh;
647 };
648
649 static int
650 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
651                       struct ext4_xattr_block_find *bs)
652 {
653         struct super_block *sb = inode->i_sb;
654         int error;
655
656         ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
657                   i->name_index, i->name, i->value, (long)i->value_len);
658
659         if (EXT4_I(inode)->i_file_acl) {
660                 /* The inode already has an extended attribute block. */
661                 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
662                 error = -EIO;
663                 if (!bs->bh)
664                         goto cleanup;
665                 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
666                         atomic_read(&(bs->bh->b_count)),
667                         le32_to_cpu(BHDR(bs->bh)->h_refcount));
668                 if (ext4_xattr_check_block(bs->bh)) {
669                         ext4_error(sb, "inode %lu: bad block %llu",
670                                    inode->i_ino, 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, "inode %lu: bad block %llu",
884                    inode->i_ino, EXT4_I(inode)->i_file_acl);
885         goto cleanup;
886
887 #undef header
888 }
889
890 struct ext4_xattr_ibody_find {
891         struct ext4_xattr_search s;
892         struct ext4_iloc iloc;
893 };
894
895 static int
896 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
897                       struct ext4_xattr_ibody_find *is)
898 {
899         struct ext4_xattr_ibody_header *header;
900         struct ext4_inode *raw_inode;
901         int error;
902
903         if (EXT4_I(inode)->i_extra_isize == 0)
904                 return 0;
905         raw_inode = ext4_raw_inode(&is->iloc);
906         header = IHDR(inode, raw_inode);
907         is->s.base = is->s.first = IFIRST(header);
908         is->s.here = is->s.first;
909         is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
910         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
911                 error = ext4_xattr_check_names(IFIRST(header), is->s.end);
912                 if (error)
913                         return error;
914                 /* Find the named attribute. */
915                 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
916                                               i->name, is->s.end -
917                                               (void *)is->s.base, 0);
918                 if (error && error != -ENODATA)
919                         return error;
920                 is->s.not_found = error;
921         }
922         return 0;
923 }
924
925 static int
926 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
927                      struct ext4_xattr_info *i,
928                      struct ext4_xattr_ibody_find *is)
929 {
930         struct ext4_xattr_ibody_header *header;
931         struct ext4_xattr_search *s = &is->s;
932         int error;
933
934         if (EXT4_I(inode)->i_extra_isize == 0)
935                 return -ENOSPC;
936         error = ext4_xattr_set_entry(i, s);
937         if (error)
938                 return error;
939         header = IHDR(inode, ext4_raw_inode(&is->iloc));
940         if (!IS_LAST_ENTRY(s->first)) {
941                 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
942                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
943         } else {
944                 header->h_magic = cpu_to_le32(0);
945                 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
946         }
947         return 0;
948 }
949
950 /*
951  * ext4_xattr_set_handle()
952  *
953  * Create, replace or remove an extended attribute for this inode. Buffer
954  * is NULL to remove an existing extended attribute, and non-NULL to
955  * either replace an existing extended attribute, or create a new extended
956  * attribute. The flags XATTR_REPLACE and XATTR_CREATE
957  * specify that an extended attribute must exist and must not exist
958  * previous to the call, respectively.
959  *
960  * Returns 0, or a negative error number on failure.
961  */
962 int
963 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
964                       const char *name, const void *value, size_t value_len,
965                       int flags)
966 {
967         struct ext4_xattr_info i = {
968                 .name_index = name_index,
969                 .name = name,
970                 .value = value,
971                 .value_len = value_len,
972
973         };
974         struct ext4_xattr_ibody_find is = {
975                 .s = { .not_found = -ENODATA, },
976         };
977         struct ext4_xattr_block_find bs = {
978                 .s = { .not_found = -ENODATA, },
979         };
980         unsigned long no_expand;
981         int error;
982
983         if (!name)
984                 return -EINVAL;
985         if (strlen(name) > 255)
986                 return -ERANGE;
987         down_write(&EXT4_I(inode)->xattr_sem);
988         no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
989         ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
990
991         error = ext4_get_inode_loc(inode, &is.iloc);
992         if (error)
993                 goto cleanup;
994
995         error = ext4_journal_get_write_access(handle, is.iloc.bh);
996         if (error)
997                 goto cleanup;
998
999         if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1000                 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1001                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1002                 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1003         }
1004
1005         error = ext4_xattr_ibody_find(inode, &i, &is);
1006         if (error)
1007                 goto cleanup;
1008         if (is.s.not_found)
1009                 error = ext4_xattr_block_find(inode, &i, &bs);
1010         if (error)
1011                 goto cleanup;
1012         if (is.s.not_found && bs.s.not_found) {
1013                 error = -ENODATA;
1014                 if (flags & XATTR_REPLACE)
1015                         goto cleanup;
1016                 error = 0;
1017                 if (!value)
1018                         goto cleanup;
1019         } else {
1020                 error = -EEXIST;
1021                 if (flags & XATTR_CREATE)
1022                         goto cleanup;
1023         }
1024         if (!value) {
1025                 if (!is.s.not_found)
1026                         error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1027                 else if (!bs.s.not_found)
1028                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1029         } else {
1030                 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1031                 if (!error && !bs.s.not_found) {
1032                         i.value = NULL;
1033                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1034                 } else if (error == -ENOSPC) {
1035                         if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1036                                 error = ext4_xattr_block_find(inode, &i, &bs);
1037                                 if (error)
1038                                         goto cleanup;
1039                         }
1040                         error = ext4_xattr_block_set(handle, inode, &i, &bs);
1041                         if (error)
1042                                 goto cleanup;
1043                         if (!is.s.not_found) {
1044                                 i.value = NULL;
1045                                 error = ext4_xattr_ibody_set(handle, inode, &i,
1046                                                              &is);
1047                         }
1048                 }
1049         }
1050         if (!error) {
1051                 ext4_xattr_update_super_block(handle, inode->i_sb);
1052                 inode->i_ctime = ext4_current_time(inode);
1053                 if (!value)
1054                         ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1055                 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1056                 /*
1057                  * The bh is consumed by ext4_mark_iloc_dirty, even with
1058                  * error != 0.
1059                  */
1060                 is.iloc.bh = NULL;
1061                 if (IS_SYNC(inode))
1062                         ext4_handle_sync(handle);
1063         }
1064
1065 cleanup:
1066         brelse(is.iloc.bh);
1067         brelse(bs.bh);
1068         if (no_expand == 0)
1069                 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1070         up_write(&EXT4_I(inode)->xattr_sem);
1071         return error;
1072 }
1073
1074 /*
1075  * ext4_xattr_set()
1076  *
1077  * Like ext4_xattr_set_handle, but start from an inode. This extended
1078  * attribute modification is a filesystem transaction by itself.
1079  *
1080  * Returns 0, or a negative error number on failure.
1081  */
1082 int
1083 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1084                const void *value, size_t value_len, int flags)
1085 {
1086         handle_t *handle;
1087         int error, retries = 0;
1088
1089 retry:
1090         handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
1091         if (IS_ERR(handle)) {
1092                 error = PTR_ERR(handle);
1093         } else {
1094                 int error2;
1095
1096                 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1097                                               value, value_len, flags);
1098                 error2 = ext4_journal_stop(handle);
1099                 if (error == -ENOSPC &&
1100                     ext4_should_retry_alloc(inode->i_sb, &retries))
1101                         goto retry;
1102                 if (error == 0)
1103                         error = error2;
1104         }
1105
1106         return error;
1107 }
1108
1109 /*
1110  * Shift the EA entries in the inode to create space for the increased
1111  * i_extra_isize.
1112  */
1113 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1114                                      int value_offs_shift, void *to,
1115                                      void *from, size_t n, int blocksize)
1116 {
1117         struct ext4_xattr_entry *last = entry;
1118         int new_offs;
1119
1120         /* Adjust the value offsets of the entries */
1121         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1122                 if (!last->e_value_block && last->e_value_size) {
1123                         new_offs = le16_to_cpu(last->e_value_offs) +
1124                                                         value_offs_shift;
1125                         BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1126                                  > blocksize);
1127                         last->e_value_offs = cpu_to_le16(new_offs);
1128                 }
1129         }
1130         /* Shift the entries by n bytes */
1131         memmove(to, from, n);
1132 }
1133
1134 /*
1135  * Expand an inode by new_extra_isize bytes when EAs are present.
1136  * Returns 0 on success or negative error number on failure.
1137  */
1138 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1139                                struct ext4_inode *raw_inode, handle_t *handle)
1140 {
1141         struct ext4_xattr_ibody_header *header;
1142         struct ext4_xattr_entry *entry, *last, *first;
1143         struct buffer_head *bh = NULL;
1144         struct ext4_xattr_ibody_find *is = NULL;
1145         struct ext4_xattr_block_find *bs = NULL;
1146         char *buffer = NULL, *b_entry_name = NULL;
1147         size_t min_offs, free;
1148         int total_ino, total_blk;
1149         void *base, *start, *end;
1150         int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1151         int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1152
1153         down_write(&EXT4_I(inode)->xattr_sem);
1154 retry:
1155         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1156                 up_write(&EXT4_I(inode)->xattr_sem);
1157                 return 0;
1158         }
1159
1160         header = IHDR(inode, raw_inode);
1161         entry = IFIRST(header);
1162
1163         /*
1164          * Check if enough free space is available in the inode to shift the
1165          * entries ahead by new_extra_isize.
1166          */
1167
1168         base = start = entry;
1169         end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1170         min_offs = end - base;
1171         last = entry;
1172         total_ino = sizeof(struct ext4_xattr_ibody_header);
1173
1174         free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1175         if (free >= new_extra_isize) {
1176                 entry = IFIRST(header);
1177                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1178                                 - new_extra_isize, (void *)raw_inode +
1179                                 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1180                                 (void *)header, total_ino,
1181                                 inode->i_sb->s_blocksize);
1182                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1183                 error = 0;
1184                 goto cleanup;
1185         }
1186
1187         /*
1188          * Enough free space isn't available in the inode, check if
1189          * EA block can hold new_extra_isize bytes.
1190          */
1191         if (EXT4_I(inode)->i_file_acl) {
1192                 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1193                 error = -EIO;
1194                 if (!bh)
1195                         goto cleanup;
1196                 if (ext4_xattr_check_block(bh)) {
1197                         ext4_error(inode->i_sb, "inode %lu: bad block %llu",
1198                                    inode->i_ino, EXT4_I(inode)->i_file_acl);
1199                         error = -EIO;
1200                         goto cleanup;
1201                 }
1202                 base = BHDR(bh);
1203                 first = BFIRST(bh);
1204                 end = bh->b_data + bh->b_size;
1205                 min_offs = end - base;
1206                 free = ext4_xattr_free_space(first, &min_offs, base,
1207                                              &total_blk);
1208                 if (free < new_extra_isize) {
1209                         if (!tried_min_extra_isize && s_min_extra_isize) {
1210                                 tried_min_extra_isize++;
1211                                 new_extra_isize = s_min_extra_isize;
1212                                 brelse(bh);
1213                                 goto retry;
1214                         }
1215                         error = -1;
1216                         goto cleanup;
1217                 }
1218         } else {
1219                 free = inode->i_sb->s_blocksize;
1220         }
1221
1222         while (new_extra_isize > 0) {
1223                 size_t offs, size, entry_size;
1224                 struct ext4_xattr_entry *small_entry = NULL;
1225                 struct ext4_xattr_info i = {
1226                         .value = NULL,
1227                         .value_len = 0,
1228                 };
1229                 unsigned int total_size;  /* EA entry size + value size */
1230                 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1231                 unsigned int min_total_size = ~0U;
1232
1233                 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1234                 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1235                 if (!is || !bs) {
1236                         error = -ENOMEM;
1237                         goto cleanup;
1238                 }
1239
1240                 is->s.not_found = -ENODATA;
1241                 bs->s.not_found = -ENODATA;
1242                 is->iloc.bh = NULL;
1243                 bs->bh = NULL;
1244
1245                 last = IFIRST(header);
1246                 /* Find the entry best suited to be pushed into EA block */
1247                 entry = NULL;
1248                 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1249                         total_size =
1250                         EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1251                                         EXT4_XATTR_LEN(last->e_name_len);
1252                         if (total_size <= free && total_size < min_total_size) {
1253                                 if (total_size < new_extra_isize) {
1254                                         small_entry = last;
1255                                 } else {
1256                                         entry = last;
1257                                         min_total_size = total_size;
1258                                 }
1259                         }
1260                 }
1261
1262                 if (entry == NULL) {
1263                         if (small_entry) {
1264                                 entry = small_entry;
1265                         } else {
1266                                 if (!tried_min_extra_isize &&
1267                                     s_min_extra_isize) {
1268                                         tried_min_extra_isize++;
1269                                         new_extra_isize = s_min_extra_isize;
1270                                         goto retry;
1271                                 }
1272                                 error = -1;
1273                                 goto cleanup;
1274                         }
1275                 }
1276                 offs = le16_to_cpu(entry->e_value_offs);
1277                 size = le32_to_cpu(entry->e_value_size);
1278                 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1279                 i.name_index = entry->e_name_index,
1280                 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1281                 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1282                 if (!buffer || !b_entry_name) {
1283                         error = -ENOMEM;
1284                         goto cleanup;
1285                 }
1286                 /* Save the entry name and the entry value */
1287                 memcpy(buffer, (void *)IFIRST(header) + offs,
1288                        EXT4_XATTR_SIZE(size));
1289                 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1290                 b_entry_name[entry->e_name_len] = '\0';
1291                 i.name = b_entry_name;
1292
1293                 error = ext4_get_inode_loc(inode, &is->iloc);
1294                 if (error)
1295                         goto cleanup;
1296
1297                 error = ext4_xattr_ibody_find(inode, &i, is);
1298                 if (error)
1299                         goto cleanup;
1300
1301                 /* Remove the chosen entry from the inode */
1302                 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1303
1304                 entry = IFIRST(header);
1305                 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1306                         shift_bytes = new_extra_isize;
1307                 else
1308                         shift_bytes = entry_size + size;
1309                 /* Adjust the offsets and shift the remaining entries ahead */
1310                 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1311                         shift_bytes, (void *)raw_inode +
1312                         EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1313                         (void *)header, total_ino - entry_size,
1314                         inode->i_sb->s_blocksize);
1315
1316                 extra_isize += shift_bytes;
1317                 new_extra_isize -= shift_bytes;
1318                 EXT4_I(inode)->i_extra_isize = extra_isize;
1319
1320                 i.name = b_entry_name;
1321                 i.value = buffer;
1322                 i.value_len = size;
1323                 error = ext4_xattr_block_find(inode, &i, bs);
1324                 if (error)
1325                         goto cleanup;
1326
1327                 /* Add entry which was removed from the inode into the block */
1328                 error = ext4_xattr_block_set(handle, inode, &i, bs);
1329                 if (error)
1330                         goto cleanup;
1331                 kfree(b_entry_name);
1332                 kfree(buffer);
1333                 b_entry_name = NULL;
1334                 buffer = NULL;
1335                 brelse(is->iloc.bh);
1336                 kfree(is);
1337                 kfree(bs);
1338         }
1339         brelse(bh);
1340         up_write(&EXT4_I(inode)->xattr_sem);
1341         return 0;
1342
1343 cleanup:
1344         kfree(b_entry_name);
1345         kfree(buffer);
1346         if (is)
1347                 brelse(is->iloc.bh);
1348         kfree(is);
1349         kfree(bs);
1350         brelse(bh);
1351         up_write(&EXT4_I(inode)->xattr_sem);
1352         return error;
1353 }
1354
1355
1356
1357 /*
1358  * ext4_xattr_delete_inode()
1359  *
1360  * Free extended attribute resources associated with this inode. This
1361  * is called immediately before an inode is freed. We have exclusive
1362  * access to the inode.
1363  */
1364 void
1365 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1366 {
1367         struct buffer_head *bh = NULL;
1368
1369         if (!EXT4_I(inode)->i_file_acl)
1370                 goto cleanup;
1371         bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1372         if (!bh) {
1373                 ext4_error(inode->i_sb, "inode %lu: block %llu read error",
1374                            inode->i_ino, EXT4_I(inode)->i_file_acl);
1375                 goto cleanup;
1376         }
1377         if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1378             BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1379                 ext4_error(inode->i_sb, "inode %lu: bad block %llu",
1380                            inode->i_ino, EXT4_I(inode)->i_file_acl);
1381                 goto cleanup;
1382         }
1383         ext4_xattr_release_block(handle, inode, bh);
1384         EXT4_I(inode)->i_file_acl = 0;
1385
1386 cleanup:
1387         brelse(bh);
1388 }
1389
1390 /*
1391  * ext4_xattr_put_super()
1392  *
1393  * This is called when a file system is unmounted.
1394  */
1395 void
1396 ext4_xattr_put_super(struct super_block *sb)
1397 {
1398         mb_cache_shrink(sb->s_bdev);
1399 }
1400
1401 /*
1402  * ext4_xattr_cache_insert()
1403  *
1404  * Create a new entry in the extended attribute cache, and insert
1405  * it unless such an entry is already in the cache.
1406  *
1407  * Returns 0, or a negative error number on failure.
1408  */
1409 static void
1410 ext4_xattr_cache_insert(struct buffer_head *bh)
1411 {
1412         __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
1413         struct mb_cache_entry *ce;
1414         int error;
1415
1416         ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
1417         if (!ce) {
1418                 ea_bdebug(bh, "out of memory");
1419                 return;
1420         }
1421         error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
1422         if (error) {
1423                 mb_cache_entry_free(ce);
1424                 if (error == -EBUSY) {
1425                         ea_bdebug(bh, "already in cache");
1426                         error = 0;
1427                 }
1428         } else {
1429                 ea_bdebug(bh, "inserting [%x]", (int)hash);
1430                 mb_cache_entry_release(ce);
1431         }
1432 }
1433
1434 /*
1435  * ext4_xattr_cmp()
1436  *
1437  * Compare two extended attribute blocks for equality.
1438  *
1439  * Returns 0 if the blocks are equal, 1 if they differ, and
1440  * a negative error number on errors.
1441  */
1442 static int
1443 ext4_xattr_cmp(struct ext4_xattr_header *header1,
1444                struct ext4_xattr_header *header2)
1445 {
1446         struct ext4_xattr_entry *entry1, *entry2;
1447
1448         entry1 = ENTRY(header1+1);
1449         entry2 = ENTRY(header2+1);
1450         while (!IS_LAST_ENTRY(entry1)) {
1451                 if (IS_LAST_ENTRY(entry2))
1452                         return 1;
1453                 if (entry1->e_hash != entry2->e_hash ||
1454                     entry1->e_name_index != entry2->e_name_index ||
1455                     entry1->e_name_len != entry2->e_name_len ||
1456                     entry1->e_value_size != entry2->e_value_size ||
1457                     memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1458                         return 1;
1459                 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1460                         return -EIO;
1461                 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1462                            (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1463                            le32_to_cpu(entry1->e_value_size)))
1464                         return 1;
1465
1466                 entry1 = EXT4_XATTR_NEXT(entry1);
1467                 entry2 = EXT4_XATTR_NEXT(entry2);
1468         }
1469         if (!IS_LAST_ENTRY(entry2))
1470                 return 1;
1471         return 0;
1472 }
1473
1474 /*
1475  * ext4_xattr_cache_find()
1476  *
1477  * Find an identical extended attribute block.
1478  *
1479  * Returns a pointer to the block found, or NULL if such a block was
1480  * not found or an error occurred.
1481  */
1482 static struct buffer_head *
1483 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1484                       struct mb_cache_entry **pce)
1485 {
1486         __u32 hash = le32_to_cpu(header->h_hash);
1487         struct mb_cache_entry *ce;
1488
1489         if (!header->h_hash)
1490                 return NULL;  /* never share */
1491         ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1492 again:
1493         ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
1494                                        inode->i_sb->s_bdev, hash);
1495         while (ce) {
1496                 struct buffer_head *bh;
1497
1498                 if (IS_ERR(ce)) {
1499                         if (PTR_ERR(ce) == -EAGAIN)
1500                                 goto again;
1501                         break;
1502                 }
1503                 bh = sb_bread(inode->i_sb, ce->e_block);
1504                 if (!bh) {
1505                         ext4_error(inode->i_sb,
1506                                 "inode %lu: block %lu read error",
1507                                 inode->i_ino, (unsigned long) ce->e_block);
1508                 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
1509                                 EXT4_XATTR_REFCOUNT_MAX) {
1510                         ea_idebug(inode, "block %lu refcount %d>=%d",
1511                                   (unsigned long) ce->e_block,
1512                                   le32_to_cpu(BHDR(bh)->h_refcount),
1513                                           EXT4_XATTR_REFCOUNT_MAX);
1514                 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1515                         *pce = ce;
1516                         return bh;
1517                 }
1518                 brelse(bh);
1519                 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
1520         }
1521         return NULL;
1522 }
1523
1524 #define NAME_HASH_SHIFT 5
1525 #define VALUE_HASH_SHIFT 16
1526
1527 /*
1528  * ext4_xattr_hash_entry()
1529  *
1530  * Compute the hash of an extended attribute.
1531  */
1532 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1533                                          struct ext4_xattr_entry *entry)
1534 {
1535         __u32 hash = 0;
1536         char *name = entry->e_name;
1537         int n;
1538
1539         for (n = 0; n < entry->e_name_len; n++) {
1540                 hash = (hash << NAME_HASH_SHIFT) ^
1541                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1542                        *name++;
1543         }
1544
1545         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1546                 __le32 *value = (__le32 *)((char *)header +
1547                         le16_to_cpu(entry->e_value_offs));
1548                 for (n = (le32_to_cpu(entry->e_value_size) +
1549                      EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1550                         hash = (hash << VALUE_HASH_SHIFT) ^
1551                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1552                                le32_to_cpu(*value++);
1553                 }
1554         }
1555         entry->e_hash = cpu_to_le32(hash);
1556 }
1557
1558 #undef NAME_HASH_SHIFT
1559 #undef VALUE_HASH_SHIFT
1560
1561 #define BLOCK_HASH_SHIFT 16
1562
1563 /*
1564  * ext4_xattr_rehash()
1565  *
1566  * Re-compute the extended attribute hash value after an entry has changed.
1567  */
1568 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1569                               struct ext4_xattr_entry *entry)
1570 {
1571         struct ext4_xattr_entry *here;
1572         __u32 hash = 0;
1573
1574         ext4_xattr_hash_entry(header, entry);
1575         here = ENTRY(header+1);
1576         while (!IS_LAST_ENTRY(here)) {
1577                 if (!here->e_hash) {
1578                         /* Block is not shared if an entry's hash value == 0 */
1579                         hash = 0;
1580                         break;
1581                 }
1582                 hash = (hash << BLOCK_HASH_SHIFT) ^
1583                        (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1584                        le32_to_cpu(here->e_hash);
1585                 here = EXT4_XATTR_NEXT(here);
1586         }
1587         header->h_hash = cpu_to_le32(hash);
1588 }
1589
1590 #undef BLOCK_HASH_SHIFT
1591
1592 int __init
1593 init_ext4_xattr(void)
1594 {
1595         ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
1596                 sizeof(struct mb_cache_entry) +
1597                 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
1598         if (!ext4_xattr_cache)
1599                 return -ENOMEM;
1600         return 0;
1601 }
1602
1603 void
1604 exit_ext4_xattr(void)
1605 {
1606         if (ext4_xattr_cache)
1607                 mb_cache_destroy(ext4_xattr_cache);
1608         ext4_xattr_cache = NULL;
1609 }