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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/ext4_jbd2.h> | |
57 | #include <linux/ext4_fs.h> | |
58 | #include <linux/mbcache.h> | |
59 | #include <linux/quotaops.h> | |
60 | #include <linux/rwsem.h> | |
61 | #include "xattr.h" | |
62 | #include "acl.h" | |
63 | ||
64 | #define BHDR(bh) ((struct 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 | ||
96 | static struct mb_cache *ext4_xattr_cache; | |
97 | ||
98 | static struct xattr_handler *ext4_xattr_handler_map[] = { | |
99 | [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, | |
100 | #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL | |
101 | [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler, | |
102 | [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler, | |
103 | #endif | |
104 | [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, | |
105 | #ifdef CONFIG_EXT4DEV_FS_SECURITY | |
106 | [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, | |
107 | #endif | |
108 | }; | |
109 | ||
110 | struct xattr_handler *ext4_xattr_handlers[] = { | |
111 | &ext4_xattr_user_handler, | |
112 | &ext4_xattr_trusted_handler, | |
113 | #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL | |
114 | &ext4_xattr_acl_access_handler, | |
115 | &ext4_xattr_acl_default_handler, | |
116 | #endif | |
117 | #ifdef CONFIG_EXT4DEV_FS_SECURITY | |
118 | &ext4_xattr_security_handler, | |
119 | #endif | |
120 | NULL | |
121 | }; | |
122 | ||
123 | static inline struct xattr_handler * | |
124 | ext4_xattr_handler(int name_index) | |
125 | { | |
126 | struct xattr_handler *handler = NULL; | |
127 | ||
128 | if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) | |
129 | handler = ext4_xattr_handler_map[name_index]; | |
130 | return handler; | |
131 | } | |
132 | ||
133 | /* | |
134 | * Inode operation listxattr() | |
135 | * | |
136 | * dentry->d_inode->i_mutex: don't care | |
137 | */ | |
138 | ssize_t | |
139 | ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
140 | { | |
141 | return ext4_xattr_list(dentry->d_inode, buffer, size); | |
142 | } | |
143 | ||
144 | static int | |
145 | ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end) | |
146 | { | |
147 | while (!IS_LAST_ENTRY(entry)) { | |
148 | struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry); | |
149 | if ((void *)next >= end) | |
150 | return -EIO; | |
151 | entry = next; | |
152 | } | |
153 | return 0; | |
154 | } | |
155 | ||
156 | static inline int | |
157 | ext4_xattr_check_block(struct buffer_head *bh) | |
158 | { | |
159 | int error; | |
160 | ||
161 | if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || | |
162 | BHDR(bh)->h_blocks != cpu_to_le32(1)) | |
163 | return -EIO; | |
164 | error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size); | |
165 | return error; | |
166 | } | |
167 | ||
168 | static inline int | |
169 | ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) | |
170 | { | |
171 | size_t value_size = le32_to_cpu(entry->e_value_size); | |
172 | ||
173 | if (entry->e_value_block != 0 || value_size > size || | |
174 | le16_to_cpu(entry->e_value_offs) + value_size > size) | |
175 | return -EIO; | |
176 | return 0; | |
177 | } | |
178 | ||
179 | static int | |
180 | ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, | |
181 | const char *name, size_t size, int sorted) | |
182 | { | |
183 | struct ext4_xattr_entry *entry; | |
184 | size_t name_len; | |
185 | int cmp = 1; | |
186 | ||
187 | if (name == NULL) | |
188 | return -EINVAL; | |
189 | name_len = strlen(name); | |
190 | entry = *pentry; | |
191 | for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { | |
192 | cmp = name_index - entry->e_name_index; | |
193 | if (!cmp) | |
194 | cmp = name_len - entry->e_name_len; | |
195 | if (!cmp) | |
196 | cmp = memcmp(name, entry->e_name, name_len); | |
197 | if (cmp <= 0 && (sorted || cmp == 0)) | |
198 | break; | |
199 | } | |
200 | *pentry = entry; | |
201 | if (!cmp && ext4_xattr_check_entry(entry, size)) | |
202 | return -EIO; | |
203 | return cmp ? -ENODATA : 0; | |
204 | } | |
205 | ||
206 | static int | |
207 | ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, | |
208 | void *buffer, size_t buffer_size) | |
209 | { | |
210 | struct buffer_head *bh = NULL; | |
211 | struct ext4_xattr_entry *entry; | |
212 | size_t size; | |
213 | int error; | |
214 | ||
215 | ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", | |
216 | name_index, name, buffer, (long)buffer_size); | |
217 | ||
218 | error = -ENODATA; | |
219 | if (!EXT4_I(inode)->i_file_acl) | |
220 | goto cleanup; | |
221 | ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); | |
222 | bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); | |
223 | if (!bh) | |
224 | goto cleanup; | |
225 | ea_bdebug(bh, "b_count=%d, refcount=%d", | |
226 | atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); | |
227 | if (ext4_xattr_check_block(bh)) { | |
228 | bad_block: ext4_error(inode->i_sb, __FUNCTION__, | |
229 | "inode %lu: bad block %llu", inode->i_ino, | |
230 | EXT4_I(inode)->i_file_acl); | |
231 | error = -EIO; | |
232 | goto cleanup; | |
233 | } | |
234 | ext4_xattr_cache_insert(bh); | |
235 | entry = BFIRST(bh); | |
236 | error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); | |
237 | if (error == -EIO) | |
238 | goto bad_block; | |
239 | if (error) | |
240 | goto cleanup; | |
241 | size = le32_to_cpu(entry->e_value_size); | |
242 | if (buffer) { | |
243 | error = -ERANGE; | |
244 | if (size > buffer_size) | |
245 | goto cleanup; | |
246 | memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), | |
247 | size); | |
248 | } | |
249 | error = size; | |
250 | ||
251 | cleanup: | |
252 | brelse(bh); | |
253 | return error; | |
254 | } | |
255 | ||
256 | static int | |
257 | ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, | |
258 | void *buffer, size_t buffer_size) | |
259 | { | |
260 | struct ext4_xattr_ibody_header *header; | |
261 | struct ext4_xattr_entry *entry; | |
262 | struct ext4_inode *raw_inode; | |
263 | struct ext4_iloc iloc; | |
264 | size_t size; | |
265 | void *end; | |
266 | int error; | |
267 | ||
268 | if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)) | |
269 | return -ENODATA; | |
270 | error = ext4_get_inode_loc(inode, &iloc); | |
271 | if (error) | |
272 | return error; | |
273 | raw_inode = ext4_raw_inode(&iloc); | |
274 | header = IHDR(inode, raw_inode); | |
275 | entry = IFIRST(header); | |
276 | end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; | |
277 | error = ext4_xattr_check_names(entry, end); | |
278 | if (error) | |
279 | goto cleanup; | |
280 | error = ext4_xattr_find_entry(&entry, name_index, name, | |
281 | end - (void *)entry, 0); | |
282 | if (error) | |
283 | goto cleanup; | |
284 | size = le32_to_cpu(entry->e_value_size); | |
285 | if (buffer) { | |
286 | error = -ERANGE; | |
287 | if (size > buffer_size) | |
288 | goto cleanup; | |
289 | memcpy(buffer, (void *)IFIRST(header) + | |
290 | le16_to_cpu(entry->e_value_offs), size); | |
291 | } | |
292 | error = size; | |
293 | ||
294 | cleanup: | |
295 | brelse(iloc.bh); | |
296 | return error; | |
297 | } | |
298 | ||
299 | /* | |
300 | * ext4_xattr_get() | |
301 | * | |
302 | * Copy an extended attribute into the buffer | |
303 | * provided, or compute the buffer size required. | |
304 | * Buffer is NULL to compute the size of the buffer required. | |
305 | * | |
306 | * Returns a negative error number on failure, or the number of bytes | |
307 | * used / required on success. | |
308 | */ | |
309 | int | |
310 | ext4_xattr_get(struct inode *inode, int name_index, const char *name, | |
311 | void *buffer, size_t buffer_size) | |
312 | { | |
313 | int error; | |
314 | ||
315 | down_read(&EXT4_I(inode)->xattr_sem); | |
316 | error = ext4_xattr_ibody_get(inode, name_index, name, buffer, | |
317 | buffer_size); | |
318 | if (error == -ENODATA) | |
319 | error = ext4_xattr_block_get(inode, name_index, name, buffer, | |
320 | buffer_size); | |
321 | up_read(&EXT4_I(inode)->xattr_sem); | |
322 | return error; | |
323 | } | |
324 | ||
325 | static int | |
326 | ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry, | |
327 | char *buffer, size_t buffer_size) | |
328 | { | |
329 | size_t rest = buffer_size; | |
330 | ||
331 | for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { | |
332 | struct xattr_handler *handler = | |
333 | ext4_xattr_handler(entry->e_name_index); | |
334 | ||
335 | if (handler) { | |
336 | size_t size = handler->list(inode, buffer, rest, | |
337 | entry->e_name, | |
338 | entry->e_name_len); | |
339 | if (buffer) { | |
340 | if (size > rest) | |
341 | return -ERANGE; | |
342 | buffer += size; | |
343 | } | |
344 | rest -= size; | |
345 | } | |
346 | } | |
347 | return buffer_size - rest; | |
348 | } | |
349 | ||
350 | static int | |
351 | ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size) | |
352 | { | |
353 | struct buffer_head *bh = NULL; | |
354 | int error; | |
355 | ||
356 | ea_idebug(inode, "buffer=%p, buffer_size=%ld", | |
357 | buffer, (long)buffer_size); | |
358 | ||
359 | error = 0; | |
360 | if (!EXT4_I(inode)->i_file_acl) | |
361 | goto cleanup; | |
362 | ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); | |
363 | bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); | |
364 | error = -EIO; | |
365 | if (!bh) | |
366 | goto cleanup; | |
367 | ea_bdebug(bh, "b_count=%d, refcount=%d", | |
368 | atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); | |
369 | if (ext4_xattr_check_block(bh)) { | |
370 | ext4_error(inode->i_sb, __FUNCTION__, | |
371 | "inode %lu: bad block %llu", inode->i_ino, | |
372 | EXT4_I(inode)->i_file_acl); | |
373 | error = -EIO; | |
374 | goto cleanup; | |
375 | } | |
376 | ext4_xattr_cache_insert(bh); | |
377 | error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size); | |
378 | ||
379 | cleanup: | |
380 | brelse(bh); | |
381 | ||
382 | return error; | |
383 | } | |
384 | ||
385 | static int | |
386 | ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size) | |
387 | { | |
388 | struct ext4_xattr_ibody_header *header; | |
389 | struct ext4_inode *raw_inode; | |
390 | struct ext4_iloc iloc; | |
391 | void *end; | |
392 | int error; | |
393 | ||
394 | if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)) | |
395 | return 0; | |
396 | error = ext4_get_inode_loc(inode, &iloc); | |
397 | if (error) | |
398 | return error; | |
399 | raw_inode = ext4_raw_inode(&iloc); | |
400 | header = IHDR(inode, raw_inode); | |
401 | end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; | |
402 | error = ext4_xattr_check_names(IFIRST(header), end); | |
403 | if (error) | |
404 | goto cleanup; | |
405 | error = ext4_xattr_list_entries(inode, IFIRST(header), | |
406 | buffer, buffer_size); | |
407 | ||
408 | cleanup: | |
409 | brelse(iloc.bh); | |
410 | return error; | |
411 | } | |
412 | ||
413 | /* | |
414 | * ext4_xattr_list() | |
415 | * | |
416 | * Copy a list of attribute names into the buffer | |
417 | * provided, or compute the buffer size required. | |
418 | * Buffer is NULL to compute the size of the buffer required. | |
419 | * | |
420 | * Returns a negative error number on failure, or the number of bytes | |
421 | * used / required on success. | |
422 | */ | |
423 | int | |
424 | ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size) | |
425 | { | |
426 | int i_error, b_error; | |
427 | ||
428 | down_read(&EXT4_I(inode)->xattr_sem); | |
429 | i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size); | |
430 | if (i_error < 0) { | |
431 | b_error = 0; | |
432 | } else { | |
433 | if (buffer) { | |
434 | buffer += i_error; | |
435 | buffer_size -= i_error; | |
436 | } | |
437 | b_error = ext4_xattr_block_list(inode, buffer, buffer_size); | |
438 | if (b_error < 0) | |
439 | i_error = 0; | |
440 | } | |
441 | up_read(&EXT4_I(inode)->xattr_sem); | |
442 | return i_error + b_error; | |
443 | } | |
444 | ||
445 | /* | |
446 | * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is | |
447 | * not set, set it. | |
448 | */ | |
449 | static void ext4_xattr_update_super_block(handle_t *handle, | |
450 | struct super_block *sb) | |
451 | { | |
452 | if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) | |
453 | return; | |
454 | ||
455 | if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { | |
456 | EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); | |
457 | sb->s_dirt = 1; | |
458 | ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh); | |
459 | } | |
460 | } | |
461 | ||
462 | /* | |
463 | * Release the xattr block BH: If the reference count is > 1, decrement | |
464 | * it; otherwise free the block. | |
465 | */ | |
466 | static void | |
467 | ext4_xattr_release_block(handle_t *handle, struct inode *inode, | |
468 | struct buffer_head *bh) | |
469 | { | |
470 | struct mb_cache_entry *ce = NULL; | |
471 | int error = 0; | |
472 | ||
473 | ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr); | |
474 | error = ext4_journal_get_write_access(handle, bh); | |
475 | if (error) | |
476 | goto out; | |
477 | ||
478 | lock_buffer(bh); | |
479 | if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { | |
480 | ea_bdebug(bh, "refcount now=0; freeing"); | |
481 | if (ce) | |
482 | mb_cache_entry_free(ce); | |
483 | ext4_free_blocks(handle, inode, bh->b_blocknr, 1, 1); | |
484 | get_bh(bh); | |
485 | ext4_forget(handle, 1, inode, bh, bh->b_blocknr); | |
486 | } else { | |
487 | BHDR(bh)->h_refcount = cpu_to_le32( | |
488 | le32_to_cpu(BHDR(bh)->h_refcount) - 1); | |
489 | error = ext4_journal_dirty_metadata(handle, bh); | |
490 | if (IS_SYNC(inode)) | |
491 | handle->h_sync = 1; | |
492 | DQUOT_FREE_BLOCK(inode, 1); | |
493 | ea_bdebug(bh, "refcount now=%d; releasing", | |
494 | le32_to_cpu(BHDR(bh)->h_refcount)); | |
495 | if (ce) | |
496 | mb_cache_entry_release(ce); | |
497 | } | |
498 | unlock_buffer(bh); | |
499 | out: | |
500 | ext4_std_error(inode->i_sb, error); | |
501 | return; | |
502 | } | |
503 | ||
504 | /* | |
505 | * Find the available free space for EAs. This also returns the total number of | |
506 | * bytes used by EA entries. | |
507 | */ | |
508 | static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, | |
509 | size_t *min_offs, void *base, int *total) | |
510 | { | |
511 | for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { | |
512 | *total += EXT4_XATTR_LEN(last->e_name_len); | |
513 | if (!last->e_value_block && last->e_value_size) { | |
514 | size_t offs = le16_to_cpu(last->e_value_offs); | |
515 | if (offs < *min_offs) | |
516 | *min_offs = offs; | |
517 | } | |
518 | } | |
519 | return (*min_offs - ((void *)last - base) - sizeof(__u32)); | |
520 | } | |
521 | ||
522 | struct ext4_xattr_info { | |
523 | int name_index; | |
524 | const char *name; | |
525 | const void *value; | |
526 | size_t value_len; | |
527 | }; | |
528 | ||
529 | struct ext4_xattr_search { | |
530 | struct ext4_xattr_entry *first; | |
531 | void *base; | |
532 | void *end; | |
533 | struct ext4_xattr_entry *here; | |
534 | int not_found; | |
535 | }; | |
536 | ||
537 | static int | |
538 | ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) | |
539 | { | |
540 | struct ext4_xattr_entry *last; | |
541 | size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); | |
542 | ||
543 | /* Compute min_offs and last. */ | |
544 | last = s->first; | |
545 | for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { | |
546 | if (!last->e_value_block && last->e_value_size) { | |
547 | size_t offs = le16_to_cpu(last->e_value_offs); | |
548 | if (offs < min_offs) | |
549 | min_offs = offs; | |
550 | } | |
551 | } | |
552 | free = min_offs - ((void *)last - s->base) - sizeof(__u32); | |
553 | if (!s->not_found) { | |
554 | if (!s->here->e_value_block && s->here->e_value_size) { | |
555 | size_t size = le32_to_cpu(s->here->e_value_size); | |
556 | free += EXT4_XATTR_SIZE(size); | |
557 | } | |
558 | free += EXT4_XATTR_LEN(name_len); | |
559 | } | |
560 | if (i->value) { | |
561 | if (free < EXT4_XATTR_SIZE(i->value_len) || | |
562 | free < EXT4_XATTR_LEN(name_len) + | |
563 | EXT4_XATTR_SIZE(i->value_len)) | |
564 | return -ENOSPC; | |
565 | } | |
566 | ||
567 | if (i->value && s->not_found) { | |
568 | /* Insert the new name. */ | |
569 | size_t size = EXT4_XATTR_LEN(name_len); | |
570 | size_t rest = (void *)last - (void *)s->here + sizeof(__u32); | |
571 | memmove((void *)s->here + size, s->here, rest); | |
572 | memset(s->here, 0, size); | |
573 | s->here->e_name_index = i->name_index; | |
574 | s->here->e_name_len = name_len; | |
575 | memcpy(s->here->e_name, i->name, name_len); | |
576 | } else { | |
577 | if (!s->here->e_value_block && s->here->e_value_size) { | |
578 | void *first_val = s->base + min_offs; | |
579 | size_t offs = le16_to_cpu(s->here->e_value_offs); | |
580 | void *val = s->base + offs; | |
581 | size_t size = EXT4_XATTR_SIZE( | |
582 | le32_to_cpu(s->here->e_value_size)); | |
583 | ||
584 | if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { | |
585 | /* The old and the new value have the same | |
586 | size. Just replace. */ | |
587 | s->here->e_value_size = | |
588 | cpu_to_le32(i->value_len); | |
589 | memset(val + size - EXT4_XATTR_PAD, 0, | |
590 | EXT4_XATTR_PAD); /* Clear pad bytes. */ | |
591 | memcpy(val, i->value, i->value_len); | |
592 | return 0; | |
593 | } | |
594 | ||
595 | /* Remove the old value. */ | |
596 | memmove(first_val + size, first_val, val - first_val); | |
597 | memset(first_val, 0, size); | |
598 | s->here->e_value_size = 0; | |
599 | s->here->e_value_offs = 0; | |
600 | min_offs += size; | |
601 | ||
602 | /* Adjust all value offsets. */ | |
603 | last = s->first; | |
604 | while (!IS_LAST_ENTRY(last)) { | |
605 | size_t o = le16_to_cpu(last->e_value_offs); | |
606 | if (!last->e_value_block && | |
607 | last->e_value_size && o < offs) | |
608 | last->e_value_offs = | |
609 | cpu_to_le16(o + size); | |
610 | last = EXT4_XATTR_NEXT(last); | |
611 | } | |
612 | } | |
613 | if (!i->value) { | |
614 | /* Remove the old name. */ | |
615 | size_t size = EXT4_XATTR_LEN(name_len); | |
616 | last = ENTRY((void *)last - size); | |
617 | memmove(s->here, (void *)s->here + size, | |
618 | (void *)last - (void *)s->here + sizeof(__u32)); | |
619 | memset(last, 0, size); | |
620 | } | |
621 | } | |
622 | ||
623 | if (i->value) { | |
624 | /* Insert the new value. */ | |
625 | s->here->e_value_size = cpu_to_le32(i->value_len); | |
626 | if (i->value_len) { | |
627 | size_t size = EXT4_XATTR_SIZE(i->value_len); | |
628 | void *val = s->base + min_offs - size; | |
629 | s->here->e_value_offs = cpu_to_le16(min_offs - size); | |
630 | memset(val + size - EXT4_XATTR_PAD, 0, | |
631 | EXT4_XATTR_PAD); /* Clear the pad bytes. */ | |
632 | memcpy(val, i->value, i->value_len); | |
633 | } | |
634 | } | |
635 | return 0; | |
636 | } | |
637 | ||
638 | struct ext4_xattr_block_find { | |
639 | struct ext4_xattr_search s; | |
640 | struct buffer_head *bh; | |
641 | }; | |
642 | ||
643 | static int | |
644 | ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, | |
645 | struct ext4_xattr_block_find *bs) | |
646 | { | |
647 | struct super_block *sb = inode->i_sb; | |
648 | int error; | |
649 | ||
650 | ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", | |
651 | i->name_index, i->name, i->value, (long)i->value_len); | |
652 | ||
653 | if (EXT4_I(inode)->i_file_acl) { | |
654 | /* The inode already has an extended attribute block. */ | |
655 | bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); | |
656 | error = -EIO; | |
657 | if (!bs->bh) | |
658 | goto cleanup; | |
659 | ea_bdebug(bs->bh, "b_count=%d, refcount=%d", | |
660 | atomic_read(&(bs->bh->b_count)), | |
661 | le32_to_cpu(BHDR(bs->bh)->h_refcount)); | |
662 | if (ext4_xattr_check_block(bs->bh)) { | |
663 | ext4_error(sb, __FUNCTION__, | |
664 | "inode %lu: bad block %llu", inode->i_ino, | |
665 | EXT4_I(inode)->i_file_acl); | |
666 | error = -EIO; | |
667 | goto cleanup; | |
668 | } | |
669 | /* Find the named attribute. */ | |
670 | bs->s.base = BHDR(bs->bh); | |
671 | bs->s.first = BFIRST(bs->bh); | |
672 | bs->s.end = bs->bh->b_data + bs->bh->b_size; | |
673 | bs->s.here = bs->s.first; | |
674 | error = ext4_xattr_find_entry(&bs->s.here, i->name_index, | |
675 | i->name, bs->bh->b_size, 1); | |
676 | if (error && error != -ENODATA) | |
677 | goto cleanup; | |
678 | bs->s.not_found = error; | |
679 | } | |
680 | error = 0; | |
681 | ||
682 | cleanup: | |
683 | return error; | |
684 | } | |
685 | ||
686 | static int | |
687 | ext4_xattr_block_set(handle_t *handle, struct inode *inode, | |
688 | struct ext4_xattr_info *i, | |
689 | struct ext4_xattr_block_find *bs) | |
690 | { | |
691 | struct super_block *sb = inode->i_sb; | |
692 | struct buffer_head *new_bh = NULL; | |
693 | struct ext4_xattr_search *s = &bs->s; | |
694 | struct mb_cache_entry *ce = NULL; | |
695 | int error = 0; | |
696 | ||
697 | #define header(x) ((struct ext4_xattr_header *)(x)) | |
698 | ||
699 | if (i->value && i->value_len > sb->s_blocksize) | |
700 | return -ENOSPC; | |
701 | if (s->base) { | |
702 | ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev, | |
703 | bs->bh->b_blocknr); | |
704 | error = ext4_journal_get_write_access(handle, bs->bh); | |
705 | if (error) | |
706 | goto cleanup; | |
707 | lock_buffer(bs->bh); | |
708 | ||
709 | if (header(s->base)->h_refcount == cpu_to_le32(1)) { | |
710 | if (ce) { | |
711 | mb_cache_entry_free(ce); | |
712 | ce = NULL; | |
713 | } | |
714 | ea_bdebug(bs->bh, "modifying in-place"); | |
715 | error = ext4_xattr_set_entry(i, s); | |
716 | if (!error) { | |
717 | if (!IS_LAST_ENTRY(s->first)) | |
718 | ext4_xattr_rehash(header(s->base), | |
719 | s->here); | |
720 | ext4_xattr_cache_insert(bs->bh); | |
721 | } | |
722 | unlock_buffer(bs->bh); | |
723 | if (error == -EIO) | |
724 | goto bad_block; | |
725 | if (!error) | |
726 | error = ext4_journal_dirty_metadata(handle, | |
727 | bs->bh); | |
728 | if (error) | |
729 | goto cleanup; | |
730 | goto inserted; | |
731 | } else { | |
732 | int offset = (char *)s->here - bs->bh->b_data; | |
733 | ||
734 | unlock_buffer(bs->bh); | |
735 | jbd2_journal_release_buffer(handle, bs->bh); | |
736 | if (ce) { | |
737 | mb_cache_entry_release(ce); | |
738 | ce = NULL; | |
739 | } | |
740 | ea_bdebug(bs->bh, "cloning"); | |
741 | s->base = kmalloc(bs->bh->b_size, GFP_KERNEL); | |
742 | error = -ENOMEM; | |
743 | if (s->base == NULL) | |
744 | goto cleanup; | |
745 | memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); | |
746 | s->first = ENTRY(header(s->base)+1); | |
747 | header(s->base)->h_refcount = cpu_to_le32(1); | |
748 | s->here = ENTRY(s->base + offset); | |
749 | s->end = s->base + bs->bh->b_size; | |
750 | } | |
751 | } else { | |
752 | /* Allocate a buffer where we construct the new block. */ | |
753 | s->base = kzalloc(sb->s_blocksize, GFP_KERNEL); | |
754 | /* assert(header == s->base) */ | |
755 | error = -ENOMEM; | |
756 | if (s->base == NULL) | |
757 | goto cleanup; | |
758 | header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); | |
759 | header(s->base)->h_blocks = cpu_to_le32(1); | |
760 | header(s->base)->h_refcount = cpu_to_le32(1); | |
761 | s->first = ENTRY(header(s->base)+1); | |
762 | s->here = ENTRY(header(s->base)+1); | |
763 | s->end = s->base + sb->s_blocksize; | |
764 | } | |
765 | ||
766 | error = ext4_xattr_set_entry(i, s); | |
767 | if (error == -EIO) | |
768 | goto bad_block; | |
769 | if (error) | |
770 | goto cleanup; | |
771 | if (!IS_LAST_ENTRY(s->first)) | |
772 | ext4_xattr_rehash(header(s->base), s->here); | |
773 | ||
774 | inserted: | |
775 | if (!IS_LAST_ENTRY(s->first)) { | |
776 | new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); | |
777 | if (new_bh) { | |
778 | /* We found an identical block in the cache. */ | |
779 | if (new_bh == bs->bh) | |
780 | ea_bdebug(new_bh, "keeping"); | |
781 | else { | |
782 | /* The old block is released after updating | |
783 | the inode. */ | |
784 | error = -EDQUOT; | |
785 | if (DQUOT_ALLOC_BLOCK(inode, 1)) | |
786 | goto cleanup; | |
787 | error = ext4_journal_get_write_access(handle, | |
788 | new_bh); | |
789 | if (error) | |
790 | goto cleanup_dquot; | |
791 | lock_buffer(new_bh); | |
792 | BHDR(new_bh)->h_refcount = cpu_to_le32(1 + | |
793 | le32_to_cpu(BHDR(new_bh)->h_refcount)); | |
794 | ea_bdebug(new_bh, "reusing; refcount now=%d", | |
795 | le32_to_cpu(BHDR(new_bh)->h_refcount)); | |
796 | unlock_buffer(new_bh); | |
797 | error = ext4_journal_dirty_metadata(handle, | |
798 | new_bh); | |
799 | if (error) | |
800 | goto cleanup_dquot; | |
801 | } | |
802 | mb_cache_entry_release(ce); | |
803 | ce = NULL; | |
804 | } else if (bs->bh && s->base == bs->bh->b_data) { | |
805 | /* We were modifying this block in-place. */ | |
806 | ea_bdebug(bs->bh, "keeping this block"); | |
807 | new_bh = bs->bh; | |
808 | get_bh(new_bh); | |
809 | } else { | |
810 | /* We need to allocate a new block */ | |
811 | ext4_fsblk_t goal = le32_to_cpu( | |
812 | EXT4_SB(sb)->s_es->s_first_data_block) + | |
813 | (ext4_fsblk_t)EXT4_I(inode)->i_block_group * | |
814 | EXT4_BLOCKS_PER_GROUP(sb); | |
815 | ext4_fsblk_t block = ext4_new_block(handle, inode, | |
816 | goal, &error); | |
817 | if (error) | |
818 | goto cleanup; | |
819 | ea_idebug(inode, "creating block %d", block); | |
820 | ||
821 | new_bh = sb_getblk(sb, block); | |
822 | if (!new_bh) { | |
823 | getblk_failed: | |
824 | ext4_free_blocks(handle, inode, block, 1, 1); | |
825 | error = -EIO; | |
826 | goto cleanup; | |
827 | } | |
828 | lock_buffer(new_bh); | |
829 | error = ext4_journal_get_create_access(handle, new_bh); | |
830 | if (error) { | |
831 | unlock_buffer(new_bh); | |
832 | goto getblk_failed; | |
833 | } | |
834 | memcpy(new_bh->b_data, s->base, new_bh->b_size); | |
835 | set_buffer_uptodate(new_bh); | |
836 | unlock_buffer(new_bh); | |
837 | ext4_xattr_cache_insert(new_bh); | |
838 | error = ext4_journal_dirty_metadata(handle, new_bh); | |
839 | if (error) | |
840 | goto cleanup; | |
841 | } | |
842 | } | |
843 | ||
844 | /* Update the inode. */ | |
845 | EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; | |
846 | ||
847 | /* Drop the previous xattr block. */ | |
848 | if (bs->bh && bs->bh != new_bh) | |
849 | ext4_xattr_release_block(handle, inode, bs->bh); | |
850 | error = 0; | |
851 | ||
852 | cleanup: | |
853 | if (ce) | |
854 | mb_cache_entry_release(ce); | |
855 | brelse(new_bh); | |
856 | if (!(bs->bh && s->base == bs->bh->b_data)) | |
857 | kfree(s->base); | |
858 | ||
859 | return error; | |
860 | ||
861 | cleanup_dquot: | |
862 | DQUOT_FREE_BLOCK(inode, 1); | |
863 | goto cleanup; | |
864 | ||
865 | bad_block: | |
866 | ext4_error(inode->i_sb, __FUNCTION__, | |
867 | "inode %lu: bad block %llu", inode->i_ino, | |
868 | EXT4_I(inode)->i_file_acl); | |
869 | goto cleanup; | |
870 | ||
871 | #undef header | |
872 | } | |
873 | ||
874 | struct ext4_xattr_ibody_find { | |
875 | struct ext4_xattr_search s; | |
876 | struct ext4_iloc iloc; | |
877 | }; | |
878 | ||
879 | static int | |
880 | ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, | |
881 | struct ext4_xattr_ibody_find *is) | |
882 | { | |
883 | struct ext4_xattr_ibody_header *header; | |
884 | struct ext4_inode *raw_inode; | |
885 | int error; | |
886 | ||
887 | if (EXT4_I(inode)->i_extra_isize == 0) | |
888 | return 0; | |
889 | raw_inode = ext4_raw_inode(&is->iloc); | |
890 | header = IHDR(inode, raw_inode); | |
891 | is->s.base = is->s.first = IFIRST(header); | |
892 | is->s.here = is->s.first; | |
893 | is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; | |
894 | if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) { | |
895 | error = ext4_xattr_check_names(IFIRST(header), is->s.end); | |
896 | if (error) | |
897 | return error; | |
898 | /* Find the named attribute. */ | |
899 | error = ext4_xattr_find_entry(&is->s.here, i->name_index, | |
900 | i->name, is->s.end - | |
901 | (void *)is->s.base, 0); | |
902 | if (error && error != -ENODATA) | |
903 | return error; | |
904 | is->s.not_found = error; | |
905 | } | |
906 | return 0; | |
907 | } | |
908 | ||
909 | static int | |
910 | ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, | |
911 | struct ext4_xattr_info *i, | |
912 | struct ext4_xattr_ibody_find *is) | |
913 | { | |
914 | struct ext4_xattr_ibody_header *header; | |
915 | struct ext4_xattr_search *s = &is->s; | |
916 | int error; | |
917 | ||
918 | if (EXT4_I(inode)->i_extra_isize == 0) | |
919 | return -ENOSPC; | |
920 | error = ext4_xattr_set_entry(i, s); | |
921 | if (error) | |
922 | return error; | |
923 | header = IHDR(inode, ext4_raw_inode(&is->iloc)); | |
924 | if (!IS_LAST_ENTRY(s->first)) { | |
925 | header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); | |
926 | EXT4_I(inode)->i_state |= EXT4_STATE_XATTR; | |
927 | } else { | |
928 | header->h_magic = cpu_to_le32(0); | |
929 | EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR; | |
930 | } | |
931 | return 0; | |
932 | } | |
933 | ||
934 | /* | |
935 | * ext4_xattr_set_handle() | |
936 | * | |
937 | * Create, replace or remove an extended attribute for this inode. Buffer | |
938 | * is NULL to remove an existing extended attribute, and non-NULL to | |
939 | * either replace an existing extended attribute, or create a new extended | |
940 | * attribute. The flags XATTR_REPLACE and XATTR_CREATE | |
941 | * specify that an extended attribute must exist and must not exist | |
942 | * previous to the call, respectively. | |
943 | * | |
944 | * Returns 0, or a negative error number on failure. | |
945 | */ | |
946 | int | |
947 | ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, | |
948 | const char *name, const void *value, size_t value_len, | |
949 | int flags) | |
950 | { | |
951 | struct ext4_xattr_info i = { | |
952 | .name_index = name_index, | |
953 | .name = name, | |
954 | .value = value, | |
955 | .value_len = value_len, | |
956 | ||
957 | }; | |
958 | struct ext4_xattr_ibody_find is = { | |
959 | .s = { .not_found = -ENODATA, }, | |
960 | }; | |
961 | struct ext4_xattr_block_find bs = { | |
962 | .s = { .not_found = -ENODATA, }, | |
963 | }; | |
964 | int error; | |
965 | ||
966 | if (!name) | |
967 | return -EINVAL; | |
968 | if (strlen(name) > 255) | |
969 | return -ERANGE; | |
970 | down_write(&EXT4_I(inode)->xattr_sem); | |
971 | error = ext4_get_inode_loc(inode, &is.iloc); | |
972 | if (error) | |
973 | goto cleanup; | |
974 | ||
975 | if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) { | |
976 | struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); | |
977 | memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); | |
978 | EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW; | |
979 | } | |
980 | ||
981 | error = ext4_xattr_ibody_find(inode, &i, &is); | |
982 | if (error) | |
983 | goto cleanup; | |
984 | if (is.s.not_found) | |
985 | error = ext4_xattr_block_find(inode, &i, &bs); | |
986 | if (error) | |
987 | goto cleanup; | |
988 | if (is.s.not_found && bs.s.not_found) { | |
989 | error = -ENODATA; | |
990 | if (flags & XATTR_REPLACE) | |
991 | goto cleanup; | |
992 | error = 0; | |
993 | if (!value) | |
994 | goto cleanup; | |
995 | } else { | |
996 | error = -EEXIST; | |
997 | if (flags & XATTR_CREATE) | |
998 | goto cleanup; | |
999 | } | |
1000 | error = ext4_journal_get_write_access(handle, is.iloc.bh); | |
1001 | if (error) | |
1002 | goto cleanup; | |
1003 | if (!value) { | |
1004 | if (!is.s.not_found) | |
1005 | error = ext4_xattr_ibody_set(handle, inode, &i, &is); | |
1006 | else if (!bs.s.not_found) | |
1007 | error = ext4_xattr_block_set(handle, inode, &i, &bs); | |
1008 | } else { | |
1009 | error = ext4_xattr_ibody_set(handle, inode, &i, &is); | |
1010 | if (!error && !bs.s.not_found) { | |
1011 | i.value = NULL; | |
1012 | error = ext4_xattr_block_set(handle, inode, &i, &bs); | |
1013 | } else if (error == -ENOSPC) { | |
1014 | error = ext4_xattr_block_set(handle, inode, &i, &bs); | |
1015 | if (error) | |
1016 | goto cleanup; | |
1017 | if (!is.s.not_found) { | |
1018 | i.value = NULL; | |
1019 | error = ext4_xattr_ibody_set(handle, inode, &i, | |
1020 | &is); | |
1021 | } | |
1022 | } | |
1023 | } | |
1024 | if (!error) { | |
1025 | ext4_xattr_update_super_block(handle, inode->i_sb); | |
1026 | inode->i_ctime = ext4_current_time(inode); | |
1027 | if (!value) | |
1028 | EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND; | |
1029 | error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); | |
1030 | /* | |
1031 | * The bh is consumed by ext4_mark_iloc_dirty, even with | |
1032 | * error != 0. | |
1033 | */ | |
1034 | is.iloc.bh = NULL; | |
1035 | if (IS_SYNC(inode)) | |
1036 | handle->h_sync = 1; | |
1037 | } | |
1038 | ||
1039 | cleanup: | |
1040 | brelse(is.iloc.bh); | |
1041 | brelse(bs.bh); | |
1042 | up_write(&EXT4_I(inode)->xattr_sem); | |
1043 | return error; | |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * ext4_xattr_set() | |
1048 | * | |
1049 | * Like ext4_xattr_set_handle, but start from an inode. This extended | |
1050 | * attribute modification is a filesystem transaction by itself. | |
1051 | * | |
1052 | * Returns 0, or a negative error number on failure. | |
1053 | */ | |
1054 | int | |
1055 | ext4_xattr_set(struct inode *inode, int name_index, const char *name, | |
1056 | const void *value, size_t value_len, int flags) | |
1057 | { | |
1058 | handle_t *handle; | |
1059 | int error, retries = 0; | |
1060 | ||
1061 | retry: | |
1062 | handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); | |
1063 | if (IS_ERR(handle)) { | |
1064 | error = PTR_ERR(handle); | |
1065 | } else { | |
1066 | int error2; | |
1067 | ||
1068 | error = ext4_xattr_set_handle(handle, inode, name_index, name, | |
1069 | value, value_len, flags); | |
1070 | error2 = ext4_journal_stop(handle); | |
1071 | if (error == -ENOSPC && | |
1072 | ext4_should_retry_alloc(inode->i_sb, &retries)) | |
1073 | goto retry; | |
1074 | if (error == 0) | |
1075 | error = error2; | |
1076 | } | |
1077 | ||
1078 | return error; | |
1079 | } | |
1080 | ||
1081 | /* | |
1082 | * Shift the EA entries in the inode to create space for the increased | |
1083 | * i_extra_isize. | |
1084 | */ | |
1085 | static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, | |
1086 | int value_offs_shift, void *to, | |
1087 | void *from, size_t n, int blocksize) | |
1088 | { | |
1089 | struct ext4_xattr_entry *last = entry; | |
1090 | int new_offs; | |
1091 | ||
1092 | /* Adjust the value offsets of the entries */ | |
1093 | for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { | |
1094 | if (!last->e_value_block && last->e_value_size) { | |
1095 | new_offs = le16_to_cpu(last->e_value_offs) + | |
1096 | value_offs_shift; | |
1097 | BUG_ON(new_offs + le32_to_cpu(last->e_value_size) | |
1098 | > blocksize); | |
1099 | last->e_value_offs = cpu_to_le16(new_offs); | |
1100 | } | |
1101 | } | |
1102 | /* Shift the entries by n bytes */ | |
1103 | memmove(to, from, n); | |
1104 | } | |
1105 | ||
1106 | /* | |
1107 | * Expand an inode by new_extra_isize bytes when EAs are present. | |
1108 | * Returns 0 on success or negative error number on failure. | |
1109 | */ | |
1110 | int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, | |
1111 | struct ext4_inode *raw_inode, handle_t *handle) | |
1112 | { | |
1113 | struct ext4_xattr_ibody_header *header; | |
1114 | struct ext4_xattr_entry *entry, *last, *first; | |
1115 | struct buffer_head *bh = NULL; | |
1116 | struct ext4_xattr_ibody_find *is = NULL; | |
1117 | struct ext4_xattr_block_find *bs = NULL; | |
1118 | char *buffer = NULL, *b_entry_name = NULL; | |
1119 | size_t min_offs, free; | |
1120 | int total_ino, total_blk; | |
1121 | void *base, *start, *end; | |
1122 | int extra_isize = 0, error = 0, tried_min_extra_isize = 0; | |
1123 | int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); | |
1124 | ||
1125 | down_write(&EXT4_I(inode)->xattr_sem); | |
1126 | retry: | |
1127 | if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { | |
1128 | up_write(&EXT4_I(inode)->xattr_sem); | |
1129 | return 0; | |
1130 | } | |
1131 | ||
1132 | header = IHDR(inode, raw_inode); | |
1133 | entry = IFIRST(header); | |
1134 | ||
1135 | /* | |
1136 | * Check if enough free space is available in the inode to shift the | |
1137 | * entries ahead by new_extra_isize. | |
1138 | */ | |
1139 | ||
1140 | base = start = entry; | |
1141 | end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; | |
1142 | min_offs = end - base; | |
1143 | last = entry; | |
1144 | total_ino = sizeof(struct ext4_xattr_ibody_header); | |
1145 | ||
1146 | free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); | |
1147 | if (free >= new_extra_isize) { | |
1148 | entry = IFIRST(header); | |
1149 | ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize | |
1150 | - new_extra_isize, (void *)raw_inode + | |
1151 | EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, | |
1152 | (void *)header, total_ino, | |
1153 | inode->i_sb->s_blocksize); | |
1154 | EXT4_I(inode)->i_extra_isize = new_extra_isize; | |
1155 | error = 0; | |
1156 | goto cleanup; | |
1157 | } | |
1158 | ||
1159 | /* | |
1160 | * Enough free space isn't available in the inode, check if | |
1161 | * EA block can hold new_extra_isize bytes. | |
1162 | */ | |
1163 | if (EXT4_I(inode)->i_file_acl) { | |
1164 | bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); | |
1165 | error = -EIO; | |
1166 | if (!bh) | |
1167 | goto cleanup; | |
1168 | if (ext4_xattr_check_block(bh)) { | |
1169 | ext4_error(inode->i_sb, __FUNCTION__, | |
1170 | "inode %lu: bad block %llu", inode->i_ino, | |
1171 | EXT4_I(inode)->i_file_acl); | |
1172 | error = -EIO; | |
1173 | goto cleanup; | |
1174 | } | |
1175 | base = BHDR(bh); | |
1176 | first = BFIRST(bh); | |
1177 | end = bh->b_data + bh->b_size; | |
1178 | min_offs = end - base; | |
1179 | free = ext4_xattr_free_space(first, &min_offs, base, | |
1180 | &total_blk); | |
1181 | if (free < new_extra_isize) { | |
1182 | if (!tried_min_extra_isize && s_min_extra_isize) { | |
1183 | tried_min_extra_isize++; | |
1184 | new_extra_isize = s_min_extra_isize; | |
1185 | brelse(bh); | |
1186 | goto retry; | |
1187 | } | |
1188 | error = -1; | |
1189 | goto cleanup; | |
1190 | } | |
1191 | } else { | |
1192 | free = inode->i_sb->s_blocksize; | |
1193 | } | |
1194 | ||
1195 | while (new_extra_isize > 0) { | |
1196 | size_t offs, size, entry_size; | |
1197 | struct ext4_xattr_entry *small_entry = NULL; | |
1198 | struct ext4_xattr_info i = { | |
1199 | .value = NULL, | |
1200 | .value_len = 0, | |
1201 | }; | |
1202 | unsigned int total_size; /* EA entry size + value size */ | |
1203 | unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ | |
1204 | unsigned int min_total_size = ~0U; | |
1205 | ||
1206 | is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); | |
1207 | bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); | |
1208 | if (!is || !bs) { | |
1209 | error = -ENOMEM; | |
1210 | goto cleanup; | |
1211 | } | |
1212 | ||
1213 | is->s.not_found = -ENODATA; | |
1214 | bs->s.not_found = -ENODATA; | |
1215 | is->iloc.bh = NULL; | |
1216 | bs->bh = NULL; | |
1217 | ||
1218 | last = IFIRST(header); | |
1219 | /* Find the entry best suited to be pushed into EA block */ | |
1220 | entry = NULL; | |
1221 | for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { | |
1222 | total_size = | |
1223 | EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + | |
1224 | EXT4_XATTR_LEN(last->e_name_len); | |
1225 | if (total_size <= free && total_size < min_total_size) { | |
1226 | if (total_size < new_extra_isize) { | |
1227 | small_entry = last; | |
1228 | } else { | |
1229 | entry = last; | |
1230 | min_total_size = total_size; | |
1231 | } | |
1232 | } | |
1233 | } | |
1234 | ||
1235 | if (entry == NULL) { | |
1236 | if (small_entry) { | |
1237 | entry = small_entry; | |
1238 | } else { | |
1239 | if (!tried_min_extra_isize && | |
1240 | s_min_extra_isize) { | |
1241 | tried_min_extra_isize++; | |
1242 | new_extra_isize = s_min_extra_isize; | |
1243 | goto retry; | |
1244 | } | |
1245 | error = -1; | |
1246 | goto cleanup; | |
1247 | } | |
1248 | } | |
1249 | offs = le16_to_cpu(entry->e_value_offs); | |
1250 | size = le32_to_cpu(entry->e_value_size); | |
1251 | entry_size = EXT4_XATTR_LEN(entry->e_name_len); | |
1252 | i.name_index = entry->e_name_index, | |
1253 | buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); | |
1254 | b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); | |
1255 | if (!buffer || !b_entry_name) { | |
1256 | error = -ENOMEM; | |
1257 | goto cleanup; | |
1258 | } | |
1259 | /* Save the entry name and the entry value */ | |
1260 | memcpy(buffer, (void *)IFIRST(header) + offs, | |
1261 | EXT4_XATTR_SIZE(size)); | |
1262 | memcpy(b_entry_name, entry->e_name, entry->e_name_len); | |
1263 | b_entry_name[entry->e_name_len] = '\0'; | |
1264 | i.name = b_entry_name; | |
1265 | ||
1266 | error = ext4_get_inode_loc(inode, &is->iloc); | |
1267 | if (error) | |
1268 | goto cleanup; | |
1269 | ||
1270 | error = ext4_xattr_ibody_find(inode, &i, is); | |
1271 | if (error) | |
1272 | goto cleanup; | |
1273 | ||
1274 | /* Remove the chosen entry from the inode */ | |
1275 | error = ext4_xattr_ibody_set(handle, inode, &i, is); | |
1276 | ||
1277 | entry = IFIRST(header); | |
1278 | if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) | |
1279 | shift_bytes = new_extra_isize; | |
1280 | else | |
1281 | shift_bytes = entry_size + size; | |
1282 | /* Adjust the offsets and shift the remaining entries ahead */ | |
1283 | ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - | |
1284 | shift_bytes, (void *)raw_inode + | |
1285 | EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, | |
1286 | (void *)header, total_ino - entry_size, | |
1287 | inode->i_sb->s_blocksize); | |
1288 | ||
1289 | extra_isize += shift_bytes; | |
1290 | new_extra_isize -= shift_bytes; | |
1291 | EXT4_I(inode)->i_extra_isize = extra_isize; | |
1292 | ||
1293 | i.name = b_entry_name; | |
1294 | i.value = buffer; | |
1295 | i.value_len = size; | |
1296 | error = ext4_xattr_block_find(inode, &i, bs); | |
1297 | if (error) | |
1298 | goto cleanup; | |
1299 | ||
1300 | /* Add entry which was removed from the inode into the block */ | |
1301 | error = ext4_xattr_block_set(handle, inode, &i, bs); | |
1302 | if (error) | |
1303 | goto cleanup; | |
1304 | kfree(b_entry_name); | |
1305 | kfree(buffer); | |
1306 | brelse(is->iloc.bh); | |
1307 | kfree(is); | |
1308 | kfree(bs); | |
1309 | } | |
1310 | brelse(bh); | |
1311 | up_write(&EXT4_I(inode)->xattr_sem); | |
1312 | return 0; | |
1313 | ||
1314 | cleanup: | |
1315 | kfree(b_entry_name); | |
1316 | kfree(buffer); | |
1317 | if (is) | |
1318 | brelse(is->iloc.bh); | |
1319 | kfree(is); | |
1320 | kfree(bs); | |
1321 | brelse(bh); | |
1322 | up_write(&EXT4_I(inode)->xattr_sem); | |
1323 | return error; | |
1324 | } | |
1325 | ||
1326 | ||
1327 | ||
1328 | /* | |
1329 | * ext4_xattr_delete_inode() | |
1330 | * | |
1331 | * Free extended attribute resources associated with this inode. This | |
1332 | * is called immediately before an inode is freed. We have exclusive | |
1333 | * access to the inode. | |
1334 | */ | |
1335 | void | |
1336 | ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) | |
1337 | { | |
1338 | struct buffer_head *bh = NULL; | |
1339 | ||
1340 | if (!EXT4_I(inode)->i_file_acl) | |
1341 | goto cleanup; | |
1342 | bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); | |
1343 | if (!bh) { | |
1344 | ext4_error(inode->i_sb, __FUNCTION__, | |
1345 | "inode %lu: block %llu read error", inode->i_ino, | |
1346 | EXT4_I(inode)->i_file_acl); | |
1347 | goto cleanup; | |
1348 | } | |
1349 | if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || | |
1350 | BHDR(bh)->h_blocks != cpu_to_le32(1)) { | |
1351 | ext4_error(inode->i_sb, __FUNCTION__, | |
1352 | "inode %lu: bad block %llu", inode->i_ino, | |
1353 | EXT4_I(inode)->i_file_acl); | |
1354 | goto cleanup; | |
1355 | } | |
1356 | ext4_xattr_release_block(handle, inode, bh); | |
1357 | EXT4_I(inode)->i_file_acl = 0; | |
1358 | ||
1359 | cleanup: | |
1360 | brelse(bh); | |
1361 | } | |
1362 | ||
1363 | /* | |
1364 | * ext4_xattr_put_super() | |
1365 | * | |
1366 | * This is called when a file system is unmounted. | |
1367 | */ | |
1368 | void | |
1369 | ext4_xattr_put_super(struct super_block *sb) | |
1370 | { | |
1371 | mb_cache_shrink(sb->s_bdev); | |
1372 | } | |
1373 | ||
1374 | /* | |
1375 | * ext4_xattr_cache_insert() | |
1376 | * | |
1377 | * Create a new entry in the extended attribute cache, and insert | |
1378 | * it unless such an entry is already in the cache. | |
1379 | * | |
1380 | * Returns 0, or a negative error number on failure. | |
1381 | */ | |
1382 | static void | |
1383 | ext4_xattr_cache_insert(struct buffer_head *bh) | |
1384 | { | |
1385 | __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); | |
1386 | struct mb_cache_entry *ce; | |
1387 | int error; | |
1388 | ||
1389 | ce = mb_cache_entry_alloc(ext4_xattr_cache); | |
1390 | if (!ce) { | |
1391 | ea_bdebug(bh, "out of memory"); | |
1392 | return; | |
1393 | } | |
1394 | error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash); | |
1395 | if (error) { | |
1396 | mb_cache_entry_free(ce); | |
1397 | if (error == -EBUSY) { | |
1398 | ea_bdebug(bh, "already in cache"); | |
1399 | error = 0; | |
1400 | } | |
1401 | } else { | |
1402 | ea_bdebug(bh, "inserting [%x]", (int)hash); | |
1403 | mb_cache_entry_release(ce); | |
1404 | } | |
1405 | } | |
1406 | ||
1407 | /* | |
1408 | * ext4_xattr_cmp() | |
1409 | * | |
1410 | * Compare two extended attribute blocks for equality. | |
1411 | * | |
1412 | * Returns 0 if the blocks are equal, 1 if they differ, and | |
1413 | * a negative error number on errors. | |
1414 | */ | |
1415 | static int | |
1416 | ext4_xattr_cmp(struct ext4_xattr_header *header1, | |
1417 | struct ext4_xattr_header *header2) | |
1418 | { | |
1419 | struct ext4_xattr_entry *entry1, *entry2; | |
1420 | ||
1421 | entry1 = ENTRY(header1+1); | |
1422 | entry2 = ENTRY(header2+1); | |
1423 | while (!IS_LAST_ENTRY(entry1)) { | |
1424 | if (IS_LAST_ENTRY(entry2)) | |
1425 | return 1; | |
1426 | if (entry1->e_hash != entry2->e_hash || | |
1427 | entry1->e_name_index != entry2->e_name_index || | |
1428 | entry1->e_name_len != entry2->e_name_len || | |
1429 | entry1->e_value_size != entry2->e_value_size || | |
1430 | memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) | |
1431 | return 1; | |
1432 | if (entry1->e_value_block != 0 || entry2->e_value_block != 0) | |
1433 | return -EIO; | |
1434 | if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), | |
1435 | (char *)header2 + le16_to_cpu(entry2->e_value_offs), | |
1436 | le32_to_cpu(entry1->e_value_size))) | |
1437 | return 1; | |
1438 | ||
1439 | entry1 = EXT4_XATTR_NEXT(entry1); | |
1440 | entry2 = EXT4_XATTR_NEXT(entry2); | |
1441 | } | |
1442 | if (!IS_LAST_ENTRY(entry2)) | |
1443 | return 1; | |
1444 | return 0; | |
1445 | } | |
1446 | ||
1447 | /* | |
1448 | * ext4_xattr_cache_find() | |
1449 | * | |
1450 | * Find an identical extended attribute block. | |
1451 | * | |
1452 | * Returns a pointer to the block found, or NULL if such a block was | |
1453 | * not found or an error occurred. | |
1454 | */ | |
1455 | static struct buffer_head * | |
1456 | ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, | |
1457 | struct mb_cache_entry **pce) | |
1458 | { | |
1459 | __u32 hash = le32_to_cpu(header->h_hash); | |
1460 | struct mb_cache_entry *ce; | |
1461 | ||
1462 | if (!header->h_hash) | |
1463 | return NULL; /* never share */ | |
1464 | ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); | |
1465 | again: | |
1466 | ce = mb_cache_entry_find_first(ext4_xattr_cache, 0, | |
1467 | inode->i_sb->s_bdev, hash); | |
1468 | while (ce) { | |
1469 | struct buffer_head *bh; | |
1470 | ||
1471 | if (IS_ERR(ce)) { | |
1472 | if (PTR_ERR(ce) == -EAGAIN) | |
1473 | goto again; | |
1474 | break; | |
1475 | } | |
1476 | bh = sb_bread(inode->i_sb, ce->e_block); | |
1477 | if (!bh) { | |
1478 | ext4_error(inode->i_sb, __FUNCTION__, | |
1479 | "inode %lu: block %lu read error", | |
1480 | inode->i_ino, (unsigned long) ce->e_block); | |
1481 | } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= | |
1482 | EXT4_XATTR_REFCOUNT_MAX) { | |
1483 | ea_idebug(inode, "block %lu refcount %d>=%d", | |
1484 | (unsigned long) ce->e_block, | |
1485 | le32_to_cpu(BHDR(bh)->h_refcount), | |
1486 | EXT4_XATTR_REFCOUNT_MAX); | |
1487 | } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { | |
1488 | *pce = ce; | |
1489 | return bh; | |
1490 | } | |
1491 | brelse(bh); | |
1492 | ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash); | |
1493 | } | |
1494 | return NULL; | |
1495 | } | |
1496 | ||
1497 | #define NAME_HASH_SHIFT 5 | |
1498 | #define VALUE_HASH_SHIFT 16 | |
1499 | ||
1500 | /* | |
1501 | * ext4_xattr_hash_entry() | |
1502 | * | |
1503 | * Compute the hash of an extended attribute. | |
1504 | */ | |
1505 | static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, | |
1506 | struct ext4_xattr_entry *entry) | |
1507 | { | |
1508 | __u32 hash = 0; | |
1509 | char *name = entry->e_name; | |
1510 | int n; | |
1511 | ||
1512 | for (n=0; n < entry->e_name_len; n++) { | |
1513 | hash = (hash << NAME_HASH_SHIFT) ^ | |
1514 | (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ | |
1515 | *name++; | |
1516 | } | |
1517 | ||
1518 | if (entry->e_value_block == 0 && entry->e_value_size != 0) { | |
1519 | __le32 *value = (__le32 *)((char *)header + | |
1520 | le16_to_cpu(entry->e_value_offs)); | |
1521 | for (n = (le32_to_cpu(entry->e_value_size) + | |
1522 | EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { | |
1523 | hash = (hash << VALUE_HASH_SHIFT) ^ | |
1524 | (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ | |
1525 | le32_to_cpu(*value++); | |
1526 | } | |
1527 | } | |
1528 | entry->e_hash = cpu_to_le32(hash); | |
1529 | } | |
1530 | ||
1531 | #undef NAME_HASH_SHIFT | |
1532 | #undef VALUE_HASH_SHIFT | |
1533 | ||
1534 | #define BLOCK_HASH_SHIFT 16 | |
1535 | ||
1536 | /* | |
1537 | * ext4_xattr_rehash() | |
1538 | * | |
1539 | * Re-compute the extended attribute hash value after an entry has changed. | |
1540 | */ | |
1541 | static void ext4_xattr_rehash(struct ext4_xattr_header *header, | |
1542 | struct ext4_xattr_entry *entry) | |
1543 | { | |
1544 | struct ext4_xattr_entry *here; | |
1545 | __u32 hash = 0; | |
1546 | ||
1547 | ext4_xattr_hash_entry(header, entry); | |
1548 | here = ENTRY(header+1); | |
1549 | while (!IS_LAST_ENTRY(here)) { | |
1550 | if (!here->e_hash) { | |
1551 | /* Block is not shared if an entry's hash value == 0 */ | |
1552 | hash = 0; | |
1553 | break; | |
1554 | } | |
1555 | hash = (hash << BLOCK_HASH_SHIFT) ^ | |
1556 | (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ | |
1557 | le32_to_cpu(here->e_hash); | |
1558 | here = EXT4_XATTR_NEXT(here); | |
1559 | } | |
1560 | header->h_hash = cpu_to_le32(hash); | |
1561 | } | |
1562 | ||
1563 | #undef BLOCK_HASH_SHIFT | |
1564 | ||
1565 | int __init | |
1566 | init_ext4_xattr(void) | |
1567 | { | |
1568 | ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL, | |
1569 | sizeof(struct mb_cache_entry) + | |
1570 | sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); | |
1571 | if (!ext4_xattr_cache) | |
1572 | return -ENOMEM; | |
1573 | return 0; | |
1574 | } | |
1575 | ||
1576 | void | |
1577 | exit_ext4_xattr(void) | |
1578 | { | |
1579 | if (ext4_xattr_cache) | |
1580 | mb_cache_destroy(ext4_xattr_cache); | |
1581 | ext4_xattr_cache = NULL; | |
1582 | } |