Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/ext2/xattr.c | |
3 | * | |
4 | * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de> | |
5 | * | |
6 | * Fix by Harrison Xing <harrison@mountainviewdata.com>. | |
7 | * Extended attributes for symlinks and special files added per | |
8 | * suggestion of Luka Renko <luka.renko@hermes.si>. | |
9 | * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>, | |
10 | * Red Hat Inc. | |
11 | * | |
12 | */ | |
13 | ||
14 | /* | |
15 | * Extended attributes are stored on disk blocks allocated outside of | |
16 | * any inode. The i_file_acl field is then made to point to this allocated | |
17 | * block. If all extended attributes of an inode are identical, these | |
18 | * inodes may share the same extended attribute block. Such situations | |
19 | * are automatically detected by keeping a cache of recent attribute block | |
20 | * numbers and hashes over the block's contents in memory. | |
21 | * | |
22 | * | |
23 | * Extended attribute block layout: | |
24 | * | |
25 | * +------------------+ | |
26 | * | header | | |
27 | * | entry 1 | | | |
28 | * | entry 2 | | growing downwards | |
29 | * | entry 3 | v | |
30 | * | four null bytes | | |
31 | * | . . . | | |
32 | * | value 1 | ^ | |
33 | * | value 3 | | growing upwards | |
34 | * | value 2 | | | |
35 | * +------------------+ | |
36 | * | |
37 | * The block header is followed by multiple entry descriptors. These entry | |
25985edc | 38 | * descriptors are variable in size, and aligned to EXT2_XATTR_PAD |
1da177e4 LT |
39 | * byte boundaries. The entry descriptors are sorted by attribute name, |
40 | * so that two extended attribute blocks can be compared efficiently. | |
41 | * | |
42 | * Attribute values are aligned to the end of the block, stored in | |
43 | * no specific order. They are also padded to EXT2_XATTR_PAD byte | |
44 | * boundaries. No additional gaps are left between them. | |
45 | * | |
46 | * Locking strategy | |
47 | * ---------------- | |
48 | * EXT2_I(inode)->i_file_acl is protected by EXT2_I(inode)->xattr_sem. | |
49 | * EA blocks are only changed if they are exclusive to an inode, so | |
50 | * holding xattr_sem also means that nothing but the EA block's reference | |
51 | * count will change. Multiple writers to an EA block are synchronized | |
52 | * by the bh lock. No more than a single bh lock is held at any time | |
53 | * to avoid deadlocks. | |
54 | */ | |
55 | ||
56 | #include <linux/buffer_head.h> | |
1da177e4 LT |
57 | #include <linux/init.h> |
58 | #include <linux/slab.h> | |
59 | #include <linux/mbcache.h> | |
60 | #include <linux/quotaops.h> | |
61 | #include <linux/rwsem.h> | |
431547b3 | 62 | #include <linux/security.h> |
1da177e4 LT |
63 | #include "ext2.h" |
64 | #include "xattr.h" | |
65 | #include "acl.h" | |
66 | ||
67 | #define HDR(bh) ((struct ext2_xattr_header *)((bh)->b_data)) | |
68 | #define ENTRY(ptr) ((struct ext2_xattr_entry *)(ptr)) | |
69 | #define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1) | |
70 | #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) | |
71 | ||
72 | #ifdef EXT2_XATTR_DEBUG | |
73 | # define ea_idebug(inode, f...) do { \ | |
74 | printk(KERN_DEBUG "inode %s:%ld: ", \ | |
75 | inode->i_sb->s_id, inode->i_ino); \ | |
76 | printk(f); \ | |
77 | printk("\n"); \ | |
78 | } while (0) | |
79 | # define ea_bdebug(bh, f...) do { \ | |
a1c6f057 DM |
80 | printk(KERN_DEBUG "block %pg:%lu: ", \ |
81 | bh->b_bdev, (unsigned long) bh->b_blocknr); \ | |
1da177e4 LT |
82 | printk(f); \ |
83 | printk("\n"); \ | |
84 | } while (0) | |
85 | #else | |
86 | # define ea_idebug(f...) | |
87 | # define ea_bdebug(f...) | |
88 | #endif | |
89 | ||
90 | static int ext2_xattr_set2(struct inode *, struct buffer_head *, | |
91 | struct ext2_xattr_header *); | |
92 | ||
93 | static int ext2_xattr_cache_insert(struct buffer_head *); | |
94 | static struct buffer_head *ext2_xattr_cache_find(struct inode *, | |
95 | struct ext2_xattr_header *); | |
96 | static void ext2_xattr_rehash(struct ext2_xattr_header *, | |
97 | struct ext2_xattr_entry *); | |
98 | ||
99 | static struct mb_cache *ext2_xattr_cache; | |
100 | ||
749c72ef | 101 | static const struct xattr_handler *ext2_xattr_handler_map[] = { |
1da177e4 LT |
102 | [EXT2_XATTR_INDEX_USER] = &ext2_xattr_user_handler, |
103 | #ifdef CONFIG_EXT2_FS_POSIX_ACL | |
64e178a7 CH |
104 | [EXT2_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler, |
105 | [EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler, | |
1da177e4 LT |
106 | #endif |
107 | [EXT2_XATTR_INDEX_TRUSTED] = &ext2_xattr_trusted_handler, | |
108 | #ifdef CONFIG_EXT2_FS_SECURITY | |
109 | [EXT2_XATTR_INDEX_SECURITY] = &ext2_xattr_security_handler, | |
110 | #endif | |
111 | }; | |
112 | ||
749c72ef | 113 | const struct xattr_handler *ext2_xattr_handlers[] = { |
1da177e4 LT |
114 | &ext2_xattr_user_handler, |
115 | &ext2_xattr_trusted_handler, | |
116 | #ifdef CONFIG_EXT2_FS_POSIX_ACL | |
64e178a7 CH |
117 | &posix_acl_access_xattr_handler, |
118 | &posix_acl_default_xattr_handler, | |
1da177e4 LT |
119 | #endif |
120 | #ifdef CONFIG_EXT2_FS_SECURITY | |
121 | &ext2_xattr_security_handler, | |
122 | #endif | |
123 | NULL | |
124 | }; | |
125 | ||
749c72ef | 126 | static inline const struct xattr_handler * |
1da177e4 LT |
127 | ext2_xattr_handler(int name_index) |
128 | { | |
749c72ef | 129 | const struct xattr_handler *handler = NULL; |
1da177e4 LT |
130 | |
131 | if (name_index > 0 && name_index < ARRAY_SIZE(ext2_xattr_handler_map)) | |
132 | handler = ext2_xattr_handler_map[name_index]; | |
133 | return handler; | |
134 | } | |
135 | ||
136 | /* | |
137 | * ext2_xattr_get() | |
138 | * | |
139 | * Copy an extended attribute into the buffer | |
140 | * provided, or compute the buffer size required. | |
141 | * Buffer is NULL to compute the size of the buffer required. | |
142 | * | |
143 | * Returns a negative error number on failure, or the number of bytes | |
144 | * used / required on success. | |
145 | */ | |
146 | int | |
147 | ext2_xattr_get(struct inode *inode, int name_index, const char *name, | |
148 | void *buffer, size_t buffer_size) | |
149 | { | |
150 | struct buffer_head *bh = NULL; | |
151 | struct ext2_xattr_entry *entry; | |
152 | size_t name_len, size; | |
153 | char *end; | |
154 | int error; | |
155 | ||
156 | ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", | |
157 | name_index, name, buffer, (long)buffer_size); | |
158 | ||
159 | if (name == NULL) | |
160 | return -EINVAL; | |
03b5bb34 WSH |
161 | name_len = strlen(name); |
162 | if (name_len > 255) | |
163 | return -ERANGE; | |
164 | ||
1da177e4 LT |
165 | down_read(&EXT2_I(inode)->xattr_sem); |
166 | error = -ENODATA; | |
167 | if (!EXT2_I(inode)->i_file_acl) | |
168 | goto cleanup; | |
169 | ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl); | |
170 | bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); | |
171 | error = -EIO; | |
172 | if (!bh) | |
173 | goto cleanup; | |
174 | ea_bdebug(bh, "b_count=%d, refcount=%d", | |
175 | atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); | |
176 | end = bh->b_data + bh->b_size; | |
177 | if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || | |
178 | HDR(bh)->h_blocks != cpu_to_le32(1)) { | |
179 | bad_block: ext2_error(inode->i_sb, "ext2_xattr_get", | |
180 | "inode %ld: bad block %d", inode->i_ino, | |
181 | EXT2_I(inode)->i_file_acl); | |
182 | error = -EIO; | |
183 | goto cleanup; | |
184 | } | |
1da177e4 | 185 | |
03b5bb34 | 186 | /* find named attribute */ |
1da177e4 LT |
187 | entry = FIRST_ENTRY(bh); |
188 | while (!IS_LAST_ENTRY(entry)) { | |
189 | struct ext2_xattr_entry *next = | |
190 | EXT2_XATTR_NEXT(entry); | |
191 | if ((char *)next >= end) | |
192 | goto bad_block; | |
193 | if (name_index == entry->e_name_index && | |
194 | name_len == entry->e_name_len && | |
195 | memcmp(name, entry->e_name, name_len) == 0) | |
196 | goto found; | |
197 | entry = next; | |
198 | } | |
1da177e4 LT |
199 | if (ext2_xattr_cache_insert(bh)) |
200 | ea_idebug(inode, "cache insert failed"); | |
201 | error = -ENODATA; | |
202 | goto cleanup; | |
203 | found: | |
204 | /* check the buffer size */ | |
205 | if (entry->e_value_block != 0) | |
206 | goto bad_block; | |
207 | size = le32_to_cpu(entry->e_value_size); | |
208 | if (size > inode->i_sb->s_blocksize || | |
209 | le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize) | |
210 | goto bad_block; | |
211 | ||
212 | if (ext2_xattr_cache_insert(bh)) | |
213 | ea_idebug(inode, "cache insert failed"); | |
214 | if (buffer) { | |
215 | error = -ERANGE; | |
216 | if (size > buffer_size) | |
217 | goto cleanup; | |
218 | /* return value of attribute */ | |
219 | memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), | |
220 | size); | |
221 | } | |
222 | error = size; | |
223 | ||
224 | cleanup: | |
225 | brelse(bh); | |
226 | up_read(&EXT2_I(inode)->xattr_sem); | |
227 | ||
228 | return error; | |
229 | } | |
230 | ||
231 | /* | |
232 | * ext2_xattr_list() | |
233 | * | |
234 | * Copy a list of attribute names into the buffer | |
235 | * provided, or compute the buffer size required. | |
236 | * Buffer is NULL to compute the size of the buffer required. | |
237 | * | |
238 | * Returns a negative error number on failure, or the number of bytes | |
239 | * used / required on success. | |
240 | */ | |
241 | static int | |
431547b3 | 242 | ext2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) |
1da177e4 | 243 | { |
2b0143b5 | 244 | struct inode *inode = d_inode(dentry); |
1da177e4 LT |
245 | struct buffer_head *bh = NULL; |
246 | struct ext2_xattr_entry *entry; | |
247 | char *end; | |
248 | size_t rest = buffer_size; | |
249 | int error; | |
250 | ||
251 | ea_idebug(inode, "buffer=%p, buffer_size=%ld", | |
252 | buffer, (long)buffer_size); | |
253 | ||
254 | down_read(&EXT2_I(inode)->xattr_sem); | |
255 | error = 0; | |
256 | if (!EXT2_I(inode)->i_file_acl) | |
257 | goto cleanup; | |
258 | ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl); | |
259 | bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); | |
260 | error = -EIO; | |
261 | if (!bh) | |
262 | goto cleanup; | |
263 | ea_bdebug(bh, "b_count=%d, refcount=%d", | |
264 | atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); | |
265 | end = bh->b_data + bh->b_size; | |
266 | if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || | |
267 | HDR(bh)->h_blocks != cpu_to_le32(1)) { | |
268 | bad_block: ext2_error(inode->i_sb, "ext2_xattr_list", | |
269 | "inode %ld: bad block %d", inode->i_ino, | |
270 | EXT2_I(inode)->i_file_acl); | |
271 | error = -EIO; | |
272 | goto cleanup; | |
273 | } | |
274 | ||
275 | /* check the on-disk data structure */ | |
276 | entry = FIRST_ENTRY(bh); | |
277 | while (!IS_LAST_ENTRY(entry)) { | |
278 | struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry); | |
279 | ||
280 | if ((char *)next >= end) | |
281 | goto bad_block; | |
282 | entry = next; | |
283 | } | |
284 | if (ext2_xattr_cache_insert(bh)) | |
285 | ea_idebug(inode, "cache insert failed"); | |
286 | ||
287 | /* list the attribute names */ | |
288 | for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry); | |
289 | entry = EXT2_XATTR_NEXT(entry)) { | |
749c72ef | 290 | const struct xattr_handler *handler = |
1da177e4 LT |
291 | ext2_xattr_handler(entry->e_name_index); |
292 | ||
293 | if (handler) { | |
d9a82a04 AG |
294 | size_t size = handler->list(handler, dentry, buffer, |
295 | rest, entry->e_name, | |
296 | entry->e_name_len); | |
1da177e4 LT |
297 | if (buffer) { |
298 | if (size > rest) { | |
299 | error = -ERANGE; | |
300 | goto cleanup; | |
301 | } | |
302 | buffer += size; | |
303 | } | |
304 | rest -= size; | |
305 | } | |
306 | } | |
307 | error = buffer_size - rest; /* total size */ | |
308 | ||
309 | cleanup: | |
310 | brelse(bh); | |
311 | up_read(&EXT2_I(inode)->xattr_sem); | |
312 | ||
313 | return error; | |
314 | } | |
315 | ||
316 | /* | |
317 | * Inode operation listxattr() | |
318 | * | |
2b0143b5 | 319 | * d_inode(dentry)->i_mutex: don't care |
1da177e4 LT |
320 | */ |
321 | ssize_t | |
322 | ext2_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
323 | { | |
431547b3 | 324 | return ext2_xattr_list(dentry, buffer, size); |
1da177e4 LT |
325 | } |
326 | ||
327 | /* | |
328 | * If the EXT2_FEATURE_COMPAT_EXT_ATTR feature of this file system is | |
329 | * not set, set it. | |
330 | */ | |
331 | static void ext2_xattr_update_super_block(struct super_block *sb) | |
332 | { | |
333 | if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR)) | |
334 | return; | |
335 | ||
c15271f4 | 336 | spin_lock(&EXT2_SB(sb)->s_lock); |
ed2908f3 | 337 | EXT2_SET_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR); |
c15271f4 | 338 | spin_unlock(&EXT2_SB(sb)->s_lock); |
1da177e4 | 339 | mark_buffer_dirty(EXT2_SB(sb)->s_sbh); |
1da177e4 LT |
340 | } |
341 | ||
342 | /* | |
343 | * ext2_xattr_set() | |
344 | * | |
6e9510b0 | 345 | * Create, replace or remove an extended attribute for this inode. Value |
1da177e4 LT |
346 | * is NULL to remove an existing extended attribute, and non-NULL to |
347 | * either replace an existing extended attribute, or create a new extended | |
348 | * attribute. The flags XATTR_REPLACE and XATTR_CREATE | |
349 | * specify that an extended attribute must exist and must not exist | |
350 | * previous to the call, respectively. | |
351 | * | |
352 | * Returns 0, or a negative error number on failure. | |
353 | */ | |
354 | int | |
355 | ext2_xattr_set(struct inode *inode, int name_index, const char *name, | |
356 | const void *value, size_t value_len, int flags) | |
357 | { | |
358 | struct super_block *sb = inode->i_sb; | |
359 | struct buffer_head *bh = NULL; | |
360 | struct ext2_xattr_header *header = NULL; | |
361 | struct ext2_xattr_entry *here, *last; | |
362 | size_t name_len, free, min_offs = sb->s_blocksize; | |
363 | int not_found = 1, error; | |
364 | char *end; | |
365 | ||
366 | /* | |
367 | * header -- Points either into bh, or to a temporarily | |
368 | * allocated buffer. | |
369 | * here -- The named entry found, or the place for inserting, within | |
370 | * the block pointed to by header. | |
371 | * last -- Points right after the last named entry within the block | |
372 | * pointed to by header. | |
373 | * min_offs -- The offset of the first value (values are aligned | |
374 | * towards the end of the block). | |
375 | * end -- Points right after the block pointed to by header. | |
376 | */ | |
377 | ||
378 | ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", | |
379 | name_index, name, value, (long)value_len); | |
380 | ||
1da177e4 LT |
381 | if (value == NULL) |
382 | value_len = 0; | |
383 | if (name == NULL) | |
384 | return -EINVAL; | |
385 | name_len = strlen(name); | |
386 | if (name_len > 255 || value_len > sb->s_blocksize) | |
387 | return -ERANGE; | |
388 | down_write(&EXT2_I(inode)->xattr_sem); | |
389 | if (EXT2_I(inode)->i_file_acl) { | |
390 | /* The inode already has an extended attribute block. */ | |
391 | bh = sb_bread(sb, EXT2_I(inode)->i_file_acl); | |
392 | error = -EIO; | |
393 | if (!bh) | |
394 | goto cleanup; | |
395 | ea_bdebug(bh, "b_count=%d, refcount=%d", | |
396 | atomic_read(&(bh->b_count)), | |
397 | le32_to_cpu(HDR(bh)->h_refcount)); | |
398 | header = HDR(bh); | |
399 | end = bh->b_data + bh->b_size; | |
400 | if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || | |
401 | header->h_blocks != cpu_to_le32(1)) { | |
402 | bad_block: ext2_error(sb, "ext2_xattr_set", | |
403 | "inode %ld: bad block %d", inode->i_ino, | |
404 | EXT2_I(inode)->i_file_acl); | |
405 | error = -EIO; | |
406 | goto cleanup; | |
407 | } | |
408 | /* Find the named attribute. */ | |
409 | here = FIRST_ENTRY(bh); | |
410 | while (!IS_LAST_ENTRY(here)) { | |
411 | struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(here); | |
412 | if ((char *)next >= end) | |
413 | goto bad_block; | |
414 | if (!here->e_value_block && here->e_value_size) { | |
415 | size_t offs = le16_to_cpu(here->e_value_offs); | |
416 | if (offs < min_offs) | |
417 | min_offs = offs; | |
418 | } | |
419 | not_found = name_index - here->e_name_index; | |
420 | if (!not_found) | |
421 | not_found = name_len - here->e_name_len; | |
422 | if (!not_found) | |
423 | not_found = memcmp(name, here->e_name,name_len); | |
424 | if (not_found <= 0) | |
425 | break; | |
426 | here = next; | |
427 | } | |
428 | last = here; | |
429 | /* We still need to compute min_offs and last. */ | |
430 | while (!IS_LAST_ENTRY(last)) { | |
431 | struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last); | |
432 | if ((char *)next >= end) | |
433 | goto bad_block; | |
434 | if (!last->e_value_block && last->e_value_size) { | |
435 | size_t offs = le16_to_cpu(last->e_value_offs); | |
436 | if (offs < min_offs) | |
437 | min_offs = offs; | |
438 | } | |
439 | last = next; | |
440 | } | |
441 | ||
442 | /* Check whether we have enough space left. */ | |
443 | free = min_offs - ((char*)last - (char*)header) - sizeof(__u32); | |
444 | } else { | |
445 | /* We will use a new extended attribute block. */ | |
446 | free = sb->s_blocksize - | |
447 | sizeof(struct ext2_xattr_header) - sizeof(__u32); | |
448 | here = last = NULL; /* avoid gcc uninitialized warning. */ | |
449 | } | |
450 | ||
451 | if (not_found) { | |
452 | /* Request to remove a nonexistent attribute? */ | |
453 | error = -ENODATA; | |
454 | if (flags & XATTR_REPLACE) | |
455 | goto cleanup; | |
456 | error = 0; | |
457 | if (value == NULL) | |
458 | goto cleanup; | |
459 | } else { | |
460 | /* Request to create an existing attribute? */ | |
461 | error = -EEXIST; | |
462 | if (flags & XATTR_CREATE) | |
463 | goto cleanup; | |
464 | if (!here->e_value_block && here->e_value_size) { | |
465 | size_t size = le32_to_cpu(here->e_value_size); | |
466 | ||
467 | if (le16_to_cpu(here->e_value_offs) + size > | |
468 | sb->s_blocksize || size > sb->s_blocksize) | |
469 | goto bad_block; | |
470 | free += EXT2_XATTR_SIZE(size); | |
471 | } | |
472 | free += EXT2_XATTR_LEN(name_len); | |
473 | } | |
474 | error = -ENOSPC; | |
475 | if (free < EXT2_XATTR_LEN(name_len) + EXT2_XATTR_SIZE(value_len)) | |
476 | goto cleanup; | |
477 | ||
478 | /* Here we know that we can set the new attribute. */ | |
479 | ||
480 | if (header) { | |
481 | struct mb_cache_entry *ce; | |
482 | ||
483 | /* assert(header == HDR(bh)); */ | |
484 | ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, | |
485 | bh->b_blocknr); | |
486 | lock_buffer(bh); | |
487 | if (header->h_refcount == cpu_to_le32(1)) { | |
488 | ea_bdebug(bh, "modifying in-place"); | |
489 | if (ce) | |
490 | mb_cache_entry_free(ce); | |
491 | /* keep the buffer locked while modifying it. */ | |
492 | } else { | |
493 | int offset; | |
494 | ||
495 | if (ce) | |
496 | mb_cache_entry_release(ce); | |
497 | unlock_buffer(bh); | |
498 | ea_bdebug(bh, "cloning"); | |
499 | header = kmalloc(bh->b_size, GFP_KERNEL); | |
500 | error = -ENOMEM; | |
501 | if (header == NULL) | |
502 | goto cleanup; | |
503 | memcpy(header, HDR(bh), bh->b_size); | |
504 | header->h_refcount = cpu_to_le32(1); | |
505 | ||
506 | offset = (char *)here - bh->b_data; | |
507 | here = ENTRY((char *)header + offset); | |
508 | offset = (char *)last - bh->b_data; | |
509 | last = ENTRY((char *)header + offset); | |
510 | } | |
511 | } else { | |
512 | /* Allocate a buffer where we construct the new block. */ | |
f8314dc6 | 513 | header = kzalloc(sb->s_blocksize, GFP_KERNEL); |
1da177e4 LT |
514 | error = -ENOMEM; |
515 | if (header == NULL) | |
516 | goto cleanup; | |
1da177e4 LT |
517 | end = (char *)header + sb->s_blocksize; |
518 | header->h_magic = cpu_to_le32(EXT2_XATTR_MAGIC); | |
519 | header->h_blocks = header->h_refcount = cpu_to_le32(1); | |
520 | last = here = ENTRY(header+1); | |
521 | } | |
522 | ||
523 | /* Iff we are modifying the block in-place, bh is locked here. */ | |
524 | ||
525 | if (not_found) { | |
526 | /* Insert the new name. */ | |
527 | size_t size = EXT2_XATTR_LEN(name_len); | |
528 | size_t rest = (char *)last - (char *)here; | |
529 | memmove((char *)here + size, here, rest); | |
530 | memset(here, 0, size); | |
531 | here->e_name_index = name_index; | |
532 | here->e_name_len = name_len; | |
533 | memcpy(here->e_name, name, name_len); | |
534 | } else { | |
535 | if (!here->e_value_block && here->e_value_size) { | |
536 | char *first_val = (char *)header + min_offs; | |
537 | size_t offs = le16_to_cpu(here->e_value_offs); | |
538 | char *val = (char *)header + offs; | |
539 | size_t size = EXT2_XATTR_SIZE( | |
540 | le32_to_cpu(here->e_value_size)); | |
541 | ||
542 | if (size == EXT2_XATTR_SIZE(value_len)) { | |
543 | /* The old and the new value have the same | |
544 | size. Just replace. */ | |
545 | here->e_value_size = cpu_to_le32(value_len); | |
546 | memset(val + size - EXT2_XATTR_PAD, 0, | |
547 | EXT2_XATTR_PAD); /* Clear pad bytes. */ | |
548 | memcpy(val, value, value_len); | |
549 | goto skip_replace; | |
550 | } | |
551 | ||
552 | /* Remove the old value. */ | |
553 | memmove(first_val + size, first_val, val - first_val); | |
554 | memset(first_val, 0, size); | |
555 | here->e_value_offs = 0; | |
556 | min_offs += size; | |
557 | ||
558 | /* Adjust all value offsets. */ | |
559 | last = ENTRY(header+1); | |
560 | while (!IS_LAST_ENTRY(last)) { | |
561 | size_t o = le16_to_cpu(last->e_value_offs); | |
562 | if (!last->e_value_block && o < offs) | |
563 | last->e_value_offs = | |
564 | cpu_to_le16(o + size); | |
565 | last = EXT2_XATTR_NEXT(last); | |
566 | } | |
567 | } | |
568 | if (value == NULL) { | |
569 | /* Remove the old name. */ | |
570 | size_t size = EXT2_XATTR_LEN(name_len); | |
571 | last = ENTRY((char *)last - size); | |
572 | memmove(here, (char*)here + size, | |
573 | (char*)last - (char*)here); | |
574 | memset(last, 0, size); | |
575 | } | |
576 | } | |
577 | ||
578 | if (value != NULL) { | |
579 | /* Insert the new value. */ | |
580 | here->e_value_size = cpu_to_le32(value_len); | |
581 | if (value_len) { | |
582 | size_t size = EXT2_XATTR_SIZE(value_len); | |
583 | char *val = (char *)header + min_offs - size; | |
584 | here->e_value_offs = | |
585 | cpu_to_le16((char *)val - (char *)header); | |
586 | memset(val + size - EXT2_XATTR_PAD, 0, | |
587 | EXT2_XATTR_PAD); /* Clear the pad bytes. */ | |
588 | memcpy(val, value, value_len); | |
589 | } | |
590 | } | |
591 | ||
592 | skip_replace: | |
593 | if (IS_LAST_ENTRY(ENTRY(header+1))) { | |
594 | /* This block is now empty. */ | |
595 | if (bh && header == HDR(bh)) | |
596 | unlock_buffer(bh); /* we were modifying in-place. */ | |
597 | error = ext2_xattr_set2(inode, bh, NULL); | |
598 | } else { | |
599 | ext2_xattr_rehash(header, here); | |
600 | if (bh && header == HDR(bh)) | |
601 | unlock_buffer(bh); /* we were modifying in-place. */ | |
602 | error = ext2_xattr_set2(inode, bh, header); | |
603 | } | |
604 | ||
605 | cleanup: | |
606 | brelse(bh); | |
607 | if (!(bh && header == HDR(bh))) | |
608 | kfree(header); | |
609 | up_write(&EXT2_I(inode)->xattr_sem); | |
610 | ||
611 | return error; | |
612 | } | |
613 | ||
614 | /* | |
615 | * Second half of ext2_xattr_set(): Update the file system. | |
616 | */ | |
617 | static int | |
618 | ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, | |
619 | struct ext2_xattr_header *header) | |
620 | { | |
621 | struct super_block *sb = inode->i_sb; | |
622 | struct buffer_head *new_bh = NULL; | |
623 | int error; | |
624 | ||
625 | if (header) { | |
626 | new_bh = ext2_xattr_cache_find(inode, header); | |
627 | if (new_bh) { | |
628 | /* We found an identical block in the cache. */ | |
629 | if (new_bh == old_bh) { | |
630 | ea_bdebug(new_bh, "keeping this block"); | |
631 | } else { | |
632 | /* The old block is released after updating | |
633 | the inode. */ | |
634 | ea_bdebug(new_bh, "reusing block"); | |
635 | ||
5dd4056d CH |
636 | error = dquot_alloc_block(inode, 1); |
637 | if (error) { | |
1da177e4 LT |
638 | unlock_buffer(new_bh); |
639 | goto cleanup; | |
640 | } | |
fba4d399 | 641 | le32_add_cpu(&HDR(new_bh)->h_refcount, 1); |
1da177e4 LT |
642 | ea_bdebug(new_bh, "refcount now=%d", |
643 | le32_to_cpu(HDR(new_bh)->h_refcount)); | |
644 | } | |
645 | unlock_buffer(new_bh); | |
646 | } else if (old_bh && header == HDR(old_bh)) { | |
647 | /* Keep this block. No need to lock the block as we | |
648 | don't need to change the reference count. */ | |
649 | new_bh = old_bh; | |
650 | get_bh(new_bh); | |
651 | ext2_xattr_cache_insert(new_bh); | |
652 | } else { | |
653 | /* We need to allocate a new block */ | |
24097d12 AM |
654 | ext2_fsblk_t goal = ext2_group_first_block_no(sb, |
655 | EXT2_I(inode)->i_block_group); | |
a686cd89 | 656 | int block = ext2_new_block(inode, goal, &error); |
1da177e4 LT |
657 | if (error) |
658 | goto cleanup; | |
659 | ea_idebug(inode, "creating block %d", block); | |
660 | ||
661 | new_bh = sb_getblk(sb, block); | |
2b0542a4 | 662 | if (unlikely(!new_bh)) { |
1da177e4 | 663 | ext2_free_blocks(inode, block, 1); |
addacc7d | 664 | mark_inode_dirty(inode); |
ab6a773d | 665 | error = -ENOMEM; |
1da177e4 LT |
666 | goto cleanup; |
667 | } | |
668 | lock_buffer(new_bh); | |
669 | memcpy(new_bh->b_data, header, new_bh->b_size); | |
670 | set_buffer_uptodate(new_bh); | |
671 | unlock_buffer(new_bh); | |
672 | ext2_xattr_cache_insert(new_bh); | |
673 | ||
674 | ext2_xattr_update_super_block(sb); | |
675 | } | |
676 | mark_buffer_dirty(new_bh); | |
677 | if (IS_SYNC(inode)) { | |
678 | sync_dirty_buffer(new_bh); | |
679 | error = -EIO; | |
680 | if (buffer_req(new_bh) && !buffer_uptodate(new_bh)) | |
681 | goto cleanup; | |
682 | } | |
683 | } | |
684 | ||
685 | /* Update the inode. */ | |
686 | EXT2_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; | |
687 | inode->i_ctime = CURRENT_TIME_SEC; | |
688 | if (IS_SYNC(inode)) { | |
c3765016 | 689 | error = sync_inode_metadata(inode, 1); |
1da177e4 LT |
690 | /* In case sync failed due to ENOSPC the inode was actually |
691 | * written (only some dirty data were not) so we just proceed | |
692 | * as if nothing happened and cleanup the unused block */ | |
693 | if (error && error != -ENOSPC) { | |
3889717d AV |
694 | if (new_bh && new_bh != old_bh) { |
695 | dquot_free_block_nodirty(inode, 1); | |
696 | mark_inode_dirty(inode); | |
697 | } | |
1da177e4 LT |
698 | goto cleanup; |
699 | } | |
700 | } else | |
701 | mark_inode_dirty(inode); | |
702 | ||
703 | error = 0; | |
704 | if (old_bh && old_bh != new_bh) { | |
705 | struct mb_cache_entry *ce; | |
706 | ||
707 | /* | |
708 | * If there was an old block and we are no longer using it, | |
709 | * release the old block. | |
710 | */ | |
711 | ce = mb_cache_entry_get(ext2_xattr_cache, old_bh->b_bdev, | |
712 | old_bh->b_blocknr); | |
713 | lock_buffer(old_bh); | |
714 | if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) { | |
715 | /* Free the old block. */ | |
716 | if (ce) | |
717 | mb_cache_entry_free(ce); | |
718 | ea_bdebug(old_bh, "freeing"); | |
719 | ext2_free_blocks(inode, old_bh->b_blocknr, 1); | |
addacc7d | 720 | mark_inode_dirty(inode); |
1da177e4 LT |
721 | /* We let our caller release old_bh, so we |
722 | * need to duplicate the buffer before. */ | |
723 | get_bh(old_bh); | |
724 | bforget(old_bh); | |
725 | } else { | |
726 | /* Decrement the refcount only. */ | |
fba4d399 | 727 | le32_add_cpu(&HDR(old_bh)->h_refcount, -1); |
1da177e4 LT |
728 | if (ce) |
729 | mb_cache_entry_release(ce); | |
3889717d AV |
730 | dquot_free_block_nodirty(inode, 1); |
731 | mark_inode_dirty(inode); | |
1da177e4 LT |
732 | mark_buffer_dirty(old_bh); |
733 | ea_bdebug(old_bh, "refcount now=%d", | |
734 | le32_to_cpu(HDR(old_bh)->h_refcount)); | |
735 | } | |
736 | unlock_buffer(old_bh); | |
737 | } | |
738 | ||
739 | cleanup: | |
740 | brelse(new_bh); | |
741 | ||
742 | return error; | |
743 | } | |
744 | ||
745 | /* | |
746 | * ext2_xattr_delete_inode() | |
747 | * | |
748 | * Free extended attribute resources associated with this inode. This | |
749 | * is called immediately before an inode is freed. | |
750 | */ | |
751 | void | |
752 | ext2_xattr_delete_inode(struct inode *inode) | |
753 | { | |
754 | struct buffer_head *bh = NULL; | |
755 | struct mb_cache_entry *ce; | |
756 | ||
757 | down_write(&EXT2_I(inode)->xattr_sem); | |
758 | if (!EXT2_I(inode)->i_file_acl) | |
759 | goto cleanup; | |
760 | bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); | |
761 | if (!bh) { | |
762 | ext2_error(inode->i_sb, "ext2_xattr_delete_inode", | |
763 | "inode %ld: block %d read error", inode->i_ino, | |
764 | EXT2_I(inode)->i_file_acl); | |
765 | goto cleanup; | |
766 | } | |
767 | ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count))); | |
768 | if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || | |
769 | HDR(bh)->h_blocks != cpu_to_le32(1)) { | |
770 | ext2_error(inode->i_sb, "ext2_xattr_delete_inode", | |
771 | "inode %ld: bad block %d", inode->i_ino, | |
772 | EXT2_I(inode)->i_file_acl); | |
773 | goto cleanup; | |
774 | } | |
775 | ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, bh->b_blocknr); | |
776 | lock_buffer(bh); | |
777 | if (HDR(bh)->h_refcount == cpu_to_le32(1)) { | |
778 | if (ce) | |
779 | mb_cache_entry_free(ce); | |
780 | ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1); | |
781 | get_bh(bh); | |
782 | bforget(bh); | |
b2f49033 | 783 | unlock_buffer(bh); |
1da177e4 | 784 | } else { |
fba4d399 | 785 | le32_add_cpu(&HDR(bh)->h_refcount, -1); |
1da177e4 LT |
786 | if (ce) |
787 | mb_cache_entry_release(ce); | |
b2f49033 PS |
788 | ea_bdebug(bh, "refcount now=%d", |
789 | le32_to_cpu(HDR(bh)->h_refcount)); | |
790 | unlock_buffer(bh); | |
1da177e4 LT |
791 | mark_buffer_dirty(bh); |
792 | if (IS_SYNC(inode)) | |
793 | sync_dirty_buffer(bh); | |
3889717d | 794 | dquot_free_block_nodirty(inode, 1); |
1da177e4 | 795 | } |
1da177e4 LT |
796 | EXT2_I(inode)->i_file_acl = 0; |
797 | ||
798 | cleanup: | |
799 | brelse(bh); | |
800 | up_write(&EXT2_I(inode)->xattr_sem); | |
801 | } | |
802 | ||
803 | /* | |
804 | * ext2_xattr_put_super() | |
805 | * | |
806 | * This is called when a file system is unmounted. | |
807 | */ | |
808 | void | |
809 | ext2_xattr_put_super(struct super_block *sb) | |
810 | { | |
8c52ab42 | 811 | mb_cache_shrink(sb->s_bdev); |
1da177e4 LT |
812 | } |
813 | ||
814 | ||
815 | /* | |
816 | * ext2_xattr_cache_insert() | |
817 | * | |
818 | * Create a new entry in the extended attribute cache, and insert | |
819 | * it unless such an entry is already in the cache. | |
820 | * | |
821 | * Returns 0, or a negative error number on failure. | |
822 | */ | |
823 | static int | |
824 | ext2_xattr_cache_insert(struct buffer_head *bh) | |
825 | { | |
826 | __u32 hash = le32_to_cpu(HDR(bh)->h_hash); | |
827 | struct mb_cache_entry *ce; | |
828 | int error; | |
829 | ||
335e92e8 | 830 | ce = mb_cache_entry_alloc(ext2_xattr_cache, GFP_NOFS); |
1da177e4 LT |
831 | if (!ce) |
832 | return -ENOMEM; | |
2aec7c52 | 833 | error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash); |
1da177e4 LT |
834 | if (error) { |
835 | mb_cache_entry_free(ce); | |
836 | if (error == -EBUSY) { | |
837 | ea_bdebug(bh, "already in cache (%d cache entries)", | |
838 | atomic_read(&ext2_xattr_cache->c_entry_count)); | |
839 | error = 0; | |
840 | } | |
841 | } else { | |
842 | ea_bdebug(bh, "inserting [%x] (%d cache entries)", (int)hash, | |
843 | atomic_read(&ext2_xattr_cache->c_entry_count)); | |
844 | mb_cache_entry_release(ce); | |
845 | } | |
846 | return error; | |
847 | } | |
848 | ||
849 | /* | |
850 | * ext2_xattr_cmp() | |
851 | * | |
852 | * Compare two extended attribute blocks for equality. | |
853 | * | |
854 | * Returns 0 if the blocks are equal, 1 if they differ, and | |
855 | * a negative error number on errors. | |
856 | */ | |
857 | static int | |
858 | ext2_xattr_cmp(struct ext2_xattr_header *header1, | |
859 | struct ext2_xattr_header *header2) | |
860 | { | |
861 | struct ext2_xattr_entry *entry1, *entry2; | |
862 | ||
863 | entry1 = ENTRY(header1+1); | |
864 | entry2 = ENTRY(header2+1); | |
865 | while (!IS_LAST_ENTRY(entry1)) { | |
866 | if (IS_LAST_ENTRY(entry2)) | |
867 | return 1; | |
868 | if (entry1->e_hash != entry2->e_hash || | |
869 | entry1->e_name_index != entry2->e_name_index || | |
870 | entry1->e_name_len != entry2->e_name_len || | |
871 | entry1->e_value_size != entry2->e_value_size || | |
872 | memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) | |
873 | return 1; | |
874 | if (entry1->e_value_block != 0 || entry2->e_value_block != 0) | |
875 | return -EIO; | |
876 | if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), | |
877 | (char *)header2 + le16_to_cpu(entry2->e_value_offs), | |
878 | le32_to_cpu(entry1->e_value_size))) | |
879 | return 1; | |
880 | ||
881 | entry1 = EXT2_XATTR_NEXT(entry1); | |
882 | entry2 = EXT2_XATTR_NEXT(entry2); | |
883 | } | |
884 | if (!IS_LAST_ENTRY(entry2)) | |
885 | return 1; | |
886 | return 0; | |
887 | } | |
888 | ||
889 | /* | |
890 | * ext2_xattr_cache_find() | |
891 | * | |
892 | * Find an identical extended attribute block. | |
893 | * | |
894 | * Returns a locked buffer head to the block found, or NULL if such | |
895 | * a block was not found or an error occurred. | |
896 | */ | |
897 | static struct buffer_head * | |
898 | ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header) | |
899 | { | |
900 | __u32 hash = le32_to_cpu(header->h_hash); | |
901 | struct mb_cache_entry *ce; | |
902 | ||
903 | if (!header->h_hash) | |
904 | return NULL; /* never share */ | |
905 | ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); | |
906 | again: | |
2aec7c52 AG |
907 | ce = mb_cache_entry_find_first(ext2_xattr_cache, inode->i_sb->s_bdev, |
908 | hash); | |
1da177e4 LT |
909 | while (ce) { |
910 | struct buffer_head *bh; | |
911 | ||
912 | if (IS_ERR(ce)) { | |
913 | if (PTR_ERR(ce) == -EAGAIN) | |
914 | goto again; | |
915 | break; | |
916 | } | |
917 | ||
918 | bh = sb_bread(inode->i_sb, ce->e_block); | |
919 | if (!bh) { | |
920 | ext2_error(inode->i_sb, "ext2_xattr_cache_find", | |
921 | "inode %ld: block %ld read error", | |
922 | inode->i_ino, (unsigned long) ce->e_block); | |
923 | } else { | |
924 | lock_buffer(bh); | |
925 | if (le32_to_cpu(HDR(bh)->h_refcount) > | |
926 | EXT2_XATTR_REFCOUNT_MAX) { | |
927 | ea_idebug(inode, "block %ld refcount %d>%d", | |
928 | (unsigned long) ce->e_block, | |
929 | le32_to_cpu(HDR(bh)->h_refcount), | |
930 | EXT2_XATTR_REFCOUNT_MAX); | |
931 | } else if (!ext2_xattr_cmp(header, HDR(bh))) { | |
932 | ea_bdebug(bh, "b_count=%d", | |
933 | atomic_read(&(bh->b_count))); | |
934 | mb_cache_entry_release(ce); | |
935 | return bh; | |
936 | } | |
937 | unlock_buffer(bh); | |
938 | brelse(bh); | |
939 | } | |
2aec7c52 | 940 | ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash); |
1da177e4 LT |
941 | } |
942 | return NULL; | |
943 | } | |
944 | ||
945 | #define NAME_HASH_SHIFT 5 | |
946 | #define VALUE_HASH_SHIFT 16 | |
947 | ||
948 | /* | |
949 | * ext2_xattr_hash_entry() | |
950 | * | |
951 | * Compute the hash of an extended attribute. | |
952 | */ | |
953 | static inline void ext2_xattr_hash_entry(struct ext2_xattr_header *header, | |
954 | struct ext2_xattr_entry *entry) | |
955 | { | |
956 | __u32 hash = 0; | |
957 | char *name = entry->e_name; | |
958 | int n; | |
959 | ||
960 | for (n=0; n < entry->e_name_len; n++) { | |
961 | hash = (hash << NAME_HASH_SHIFT) ^ | |
962 | (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ | |
963 | *name++; | |
964 | } | |
965 | ||
966 | if (entry->e_value_block == 0 && entry->e_value_size != 0) { | |
967 | __le32 *value = (__le32 *)((char *)header + | |
968 | le16_to_cpu(entry->e_value_offs)); | |
969 | for (n = (le32_to_cpu(entry->e_value_size) + | |
970 | EXT2_XATTR_ROUND) >> EXT2_XATTR_PAD_BITS; n; n--) { | |
971 | hash = (hash << VALUE_HASH_SHIFT) ^ | |
972 | (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ | |
973 | le32_to_cpu(*value++); | |
974 | } | |
975 | } | |
976 | entry->e_hash = cpu_to_le32(hash); | |
977 | } | |
978 | ||
979 | #undef NAME_HASH_SHIFT | |
980 | #undef VALUE_HASH_SHIFT | |
981 | ||
982 | #define BLOCK_HASH_SHIFT 16 | |
983 | ||
984 | /* | |
985 | * ext2_xattr_rehash() | |
986 | * | |
987 | * Re-compute the extended attribute hash value after an entry has changed. | |
988 | */ | |
989 | static void ext2_xattr_rehash(struct ext2_xattr_header *header, | |
990 | struct ext2_xattr_entry *entry) | |
991 | { | |
992 | struct ext2_xattr_entry *here; | |
993 | __u32 hash = 0; | |
994 | ||
995 | ext2_xattr_hash_entry(header, entry); | |
996 | here = ENTRY(header+1); | |
997 | while (!IS_LAST_ENTRY(here)) { | |
998 | if (!here->e_hash) { | |
999 | /* Block is not shared if an entry's hash value == 0 */ | |
1000 | hash = 0; | |
1001 | break; | |
1002 | } | |
1003 | hash = (hash << BLOCK_HASH_SHIFT) ^ | |
1004 | (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ | |
1005 | le32_to_cpu(here->e_hash); | |
1006 | here = EXT2_XATTR_NEXT(here); | |
1007 | } | |
1008 | header->h_hash = cpu_to_le32(hash); | |
1009 | } | |
1010 | ||
1011 | #undef BLOCK_HASH_SHIFT | |
1012 | ||
1013 | int __init | |
1014 | init_ext2_xattr(void) | |
1015 | { | |
2aec7c52 | 1016 | ext2_xattr_cache = mb_cache_create("ext2_xattr", 6); |
1da177e4 LT |
1017 | if (!ext2_xattr_cache) |
1018 | return -ENOMEM; | |
1019 | return 0; | |
1020 | } | |
1021 | ||
1022 | void | |
1023 | exit_ext2_xattr(void) | |
1024 | { | |
1025 | mb_cache_destroy(ext2_xattr_cache); | |
1026 | } |