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Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/libfs.c | |
3 | * Library for filesystems writers. | |
4 | */ | |
5 | ||
6 | #include <linux/module.h> | |
7 | #include <linux/pagemap.h> | |
5a0e3ad6 | 8 | #include <linux/slab.h> |
1da177e4 LT |
9 | #include <linux/mount.h> |
10 | #include <linux/vfs.h> | |
7bb46a67 | 11 | #include <linux/quotaops.h> |
7cf34c76 | 12 | #include <linux/mutex.h> |
2596110a | 13 | #include <linux/exportfs.h> |
d5aacad5 AV |
14 | #include <linux/writeback.h> |
15 | #include <linux/buffer_head.h> | |
7cf34c76 | 16 | |
1da177e4 LT |
17 | #include <asm/uaccess.h> |
18 | ||
da502956 NP |
19 | static inline int simple_positive(struct dentry *dentry) |
20 | { | |
21 | return dentry->d_inode && !d_unhashed(dentry); | |
22 | } | |
23 | ||
1da177e4 LT |
24 | int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, |
25 | struct kstat *stat) | |
26 | { | |
27 | struct inode *inode = dentry->d_inode; | |
28 | generic_fillattr(inode, stat); | |
29 | stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); | |
30 | return 0; | |
31 | } | |
32 | ||
726c3342 | 33 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 34 | { |
726c3342 | 35 | buf->f_type = dentry->d_sb->s_magic; |
1da177e4 LT |
36 | buf->f_bsize = PAGE_CACHE_SIZE; |
37 | buf->f_namelen = NAME_MAX; | |
38 | return 0; | |
39 | } | |
40 | ||
41 | /* | |
42 | * Retaining negative dentries for an in-memory filesystem just wastes | |
43 | * memory and lookup time: arrange for them to be deleted immediately. | |
44 | */ | |
fe15ce44 | 45 | static int simple_delete_dentry(const struct dentry *dentry) |
1da177e4 LT |
46 | { |
47 | return 1; | |
48 | } | |
49 | ||
50 | /* | |
51 | * Lookup the data. This is trivial - if the dentry didn't already | |
52 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
53 | */ | |
54 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) | |
55 | { | |
3ba13d17 | 56 | static const struct dentry_operations simple_dentry_operations = { |
1da177e4 LT |
57 | .d_delete = simple_delete_dentry, |
58 | }; | |
59 | ||
60 | if (dentry->d_name.len > NAME_MAX) | |
61 | return ERR_PTR(-ENAMETOOLONG); | |
fb045adb | 62 | d_set_d_op(dentry, &simple_dentry_operations); |
1da177e4 LT |
63 | d_add(dentry, NULL); |
64 | return NULL; | |
65 | } | |
66 | ||
1da177e4 LT |
67 | int dcache_dir_open(struct inode *inode, struct file *file) |
68 | { | |
69 | static struct qstr cursor_name = {.len = 1, .name = "."}; | |
70 | ||
0f7fc9e4 | 71 | file->private_data = d_alloc(file->f_path.dentry, &cursor_name); |
1da177e4 LT |
72 | |
73 | return file->private_data ? 0 : -ENOMEM; | |
74 | } | |
75 | ||
76 | int dcache_dir_close(struct inode *inode, struct file *file) | |
77 | { | |
78 | dput(file->private_data); | |
79 | return 0; | |
80 | } | |
81 | ||
82 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) | |
83 | { | |
2fd6b7f5 NP |
84 | struct dentry *dentry = file->f_path.dentry; |
85 | mutex_lock(&dentry->d_inode->i_mutex); | |
1da177e4 LT |
86 | switch (origin) { |
87 | case 1: | |
88 | offset += file->f_pos; | |
89 | case 0: | |
90 | if (offset >= 0) | |
91 | break; | |
92 | default: | |
2fd6b7f5 | 93 | mutex_unlock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
94 | return -EINVAL; |
95 | } | |
96 | if (offset != file->f_pos) { | |
97 | file->f_pos = offset; | |
98 | if (file->f_pos >= 2) { | |
99 | struct list_head *p; | |
100 | struct dentry *cursor = file->private_data; | |
101 | loff_t n = file->f_pos - 2; | |
102 | ||
2fd6b7f5 NP |
103 | spin_lock(&dentry->d_lock); |
104 | /* d_lock not required for cursor */ | |
5160ee6f | 105 | list_del(&cursor->d_u.d_child); |
2fd6b7f5 NP |
106 | p = dentry->d_subdirs.next; |
107 | while (n && p != &dentry->d_subdirs) { | |
1da177e4 | 108 | struct dentry *next; |
5160ee6f | 109 | next = list_entry(p, struct dentry, d_u.d_child); |
2fd6b7f5 | 110 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); |
da502956 | 111 | if (simple_positive(next)) |
1da177e4 | 112 | n--; |
da502956 | 113 | spin_unlock(&next->d_lock); |
1da177e4 LT |
114 | p = p->next; |
115 | } | |
5160ee6f | 116 | list_add_tail(&cursor->d_u.d_child, p); |
2fd6b7f5 | 117 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
118 | } |
119 | } | |
2fd6b7f5 | 120 | mutex_unlock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
121 | return offset; |
122 | } | |
123 | ||
124 | /* Relationship between i_mode and the DT_xxx types */ | |
125 | static inline unsigned char dt_type(struct inode *inode) | |
126 | { | |
127 | return (inode->i_mode >> 12) & 15; | |
128 | } | |
129 | ||
130 | /* | |
131 | * Directory is locked and all positive dentries in it are safe, since | |
132 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
133 | * both impossible due to the lock on directory. | |
134 | */ | |
135 | ||
136 | int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
137 | { | |
0f7fc9e4 | 138 | struct dentry *dentry = filp->f_path.dentry; |
1da177e4 | 139 | struct dentry *cursor = filp->private_data; |
5160ee6f | 140 | struct list_head *p, *q = &cursor->d_u.d_child; |
1da177e4 LT |
141 | ino_t ino; |
142 | int i = filp->f_pos; | |
143 | ||
144 | switch (i) { | |
145 | case 0: | |
146 | ino = dentry->d_inode->i_ino; | |
147 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
148 | break; | |
149 | filp->f_pos++; | |
150 | i++; | |
151 | /* fallthrough */ | |
152 | case 1: | |
153 | ino = parent_ino(dentry); | |
154 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
155 | break; | |
156 | filp->f_pos++; | |
157 | i++; | |
158 | /* fallthrough */ | |
159 | default: | |
2fd6b7f5 | 160 | spin_lock(&dentry->d_lock); |
1bfba4e8 AM |
161 | if (filp->f_pos == 2) |
162 | list_move(q, &dentry->d_subdirs); | |
163 | ||
1da177e4 LT |
164 | for (p=q->next; p != &dentry->d_subdirs; p=p->next) { |
165 | struct dentry *next; | |
5160ee6f | 166 | next = list_entry(p, struct dentry, d_u.d_child); |
da502956 NP |
167 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); |
168 | if (!simple_positive(next)) { | |
169 | spin_unlock(&next->d_lock); | |
1da177e4 | 170 | continue; |
da502956 | 171 | } |
1da177e4 | 172 | |
da502956 | 173 | spin_unlock(&next->d_lock); |
2fd6b7f5 | 174 | spin_unlock(&dentry->d_lock); |
0f8952c2 RN |
175 | if (filldir(dirent, next->d_name.name, |
176 | next->d_name.len, filp->f_pos, | |
177 | next->d_inode->i_ino, | |
178 | dt_type(next->d_inode)) < 0) | |
1da177e4 | 179 | return 0; |
2fd6b7f5 NP |
180 | spin_lock(&dentry->d_lock); |
181 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); | |
1da177e4 | 182 | /* next is still alive */ |
1bfba4e8 | 183 | list_move(q, p); |
2fd6b7f5 | 184 | spin_unlock(&next->d_lock); |
1da177e4 LT |
185 | p = q; |
186 | filp->f_pos++; | |
187 | } | |
2fd6b7f5 | 188 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
189 | } |
190 | return 0; | |
191 | } | |
192 | ||
193 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
194 | { | |
195 | return -EISDIR; | |
196 | } | |
197 | ||
4b6f5d20 | 198 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
199 | .open = dcache_dir_open, |
200 | .release = dcache_dir_close, | |
201 | .llseek = dcache_dir_lseek, | |
202 | .read = generic_read_dir, | |
203 | .readdir = dcache_readdir, | |
1b061d92 | 204 | .fsync = noop_fsync, |
1da177e4 LT |
205 | }; |
206 | ||
92e1d5be | 207 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
208 | .lookup = simple_lookup, |
209 | }; | |
210 | ||
759b9775 HD |
211 | static const struct super_operations simple_super_operations = { |
212 | .statfs = simple_statfs, | |
213 | }; | |
214 | ||
1da177e4 LT |
215 | /* |
216 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
217 | * will never be mountable) | |
218 | */ | |
51139ada AV |
219 | struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, |
220 | const struct super_operations *ops, unsigned long magic) | |
1da177e4 LT |
221 | { |
222 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); | |
1da177e4 LT |
223 | struct dentry *dentry; |
224 | struct inode *root; | |
225 | struct qstr d_name = {.name = name, .len = strlen(name)}; | |
226 | ||
227 | if (IS_ERR(s)) | |
51139ada | 228 | return ERR_CAST(s); |
1da177e4 LT |
229 | |
230 | s->s_flags = MS_NOUSER; | |
89a4eb4b | 231 | s->s_maxbytes = MAX_LFS_FILESIZE; |
3971e1a9 AN |
232 | s->s_blocksize = PAGE_SIZE; |
233 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 234 | s->s_magic = magic; |
759b9775 | 235 | s->s_op = ops ? ops : &simple_super_operations; |
1da177e4 LT |
236 | s->s_time_gran = 1; |
237 | root = new_inode(s); | |
238 | if (!root) | |
239 | goto Enomem; | |
1a1c9bb4 JL |
240 | /* |
241 | * since this is the first inode, make it number 1. New inodes created | |
242 | * after this must take care not to collide with it (by passing | |
243 | * max_reserved of 1 to iunique). | |
244 | */ | |
245 | root->i_ino = 1; | |
1da177e4 | 246 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
1da177e4 LT |
247 | root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; |
248 | dentry = d_alloc(NULL, &d_name); | |
249 | if (!dentry) { | |
250 | iput(root); | |
251 | goto Enomem; | |
252 | } | |
253 | dentry->d_sb = s; | |
254 | dentry->d_parent = dentry; | |
255 | d_instantiate(dentry, root); | |
256 | s->s_root = dentry; | |
257 | s->s_flags |= MS_ACTIVE; | |
51139ada | 258 | return dget(s->s_root); |
1da177e4 LT |
259 | |
260 | Enomem: | |
6f5bbff9 | 261 | deactivate_locked_super(s); |
51139ada | 262 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
263 | } |
264 | ||
265 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
266 | { | |
267 | struct inode *inode = old_dentry->d_inode; | |
268 | ||
269 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 270 | inc_nlink(inode); |
7de9c6ee | 271 | ihold(inode); |
1da177e4 LT |
272 | dget(dentry); |
273 | d_instantiate(dentry, inode); | |
274 | return 0; | |
275 | } | |
276 | ||
1da177e4 LT |
277 | int simple_empty(struct dentry *dentry) |
278 | { | |
279 | struct dentry *child; | |
280 | int ret = 0; | |
281 | ||
2fd6b7f5 | 282 | spin_lock(&dentry->d_lock); |
da502956 NP |
283 | list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) { |
284 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); | |
285 | if (simple_positive(child)) { | |
286 | spin_unlock(&child->d_lock); | |
1da177e4 | 287 | goto out; |
da502956 NP |
288 | } |
289 | spin_unlock(&child->d_lock); | |
290 | } | |
1da177e4 LT |
291 | ret = 1; |
292 | out: | |
2fd6b7f5 | 293 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
294 | return ret; |
295 | } | |
296 | ||
297 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
298 | { | |
299 | struct inode *inode = dentry->d_inode; | |
300 | ||
301 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 302 | drop_nlink(inode); |
1da177e4 LT |
303 | dput(dentry); |
304 | return 0; | |
305 | } | |
306 | ||
307 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
308 | { | |
309 | if (!simple_empty(dentry)) | |
310 | return -ENOTEMPTY; | |
311 | ||
9a53c3a7 | 312 | drop_nlink(dentry->d_inode); |
1da177e4 | 313 | simple_unlink(dir, dentry); |
9a53c3a7 | 314 | drop_nlink(dir); |
1da177e4 LT |
315 | return 0; |
316 | } | |
317 | ||
318 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, | |
319 | struct inode *new_dir, struct dentry *new_dentry) | |
320 | { | |
321 | struct inode *inode = old_dentry->d_inode; | |
322 | int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); | |
323 | ||
324 | if (!simple_empty(new_dentry)) | |
325 | return -ENOTEMPTY; | |
326 | ||
327 | if (new_dentry->d_inode) { | |
328 | simple_unlink(new_dir, new_dentry); | |
329 | if (they_are_dirs) | |
9a53c3a7 | 330 | drop_nlink(old_dir); |
1da177e4 | 331 | } else if (they_are_dirs) { |
9a53c3a7 | 332 | drop_nlink(old_dir); |
d8c76e6f | 333 | inc_nlink(new_dir); |
1da177e4 LT |
334 | } |
335 | ||
336 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = | |
337 | new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; | |
338 | ||
339 | return 0; | |
340 | } | |
341 | ||
7bb46a67 | 342 | /** |
eef2380c | 343 | * simple_setattr - setattr for simple filesystem |
7bb46a67 | 344 | * @dentry: dentry |
345 | * @iattr: iattr structure | |
346 | * | |
347 | * Returns 0 on success, -error on failure. | |
348 | * | |
eef2380c CH |
349 | * simple_setattr is a simple ->setattr implementation without a proper |
350 | * implementation of size changes. | |
351 | * | |
352 | * It can either be used for in-memory filesystems or special files | |
353 | * on simple regular filesystems. Anything that needs to change on-disk | |
354 | * or wire state on size changes needs its own setattr method. | |
7bb46a67 | 355 | */ |
356 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) | |
357 | { | |
358 | struct inode *inode = dentry->d_inode; | |
359 | int error; | |
360 | ||
eef2380c CH |
361 | WARN_ON_ONCE(inode->i_op->truncate); |
362 | ||
7bb46a67 | 363 | error = inode_change_ok(inode, iattr); |
364 | if (error) | |
365 | return error; | |
366 | ||
2c27c65e CH |
367 | if (iattr->ia_valid & ATTR_SIZE) |
368 | truncate_setsize(inode, iattr->ia_size); | |
6a1a90ad | 369 | setattr_copy(inode, iattr); |
eef2380c CH |
370 | mark_inode_dirty(inode); |
371 | return 0; | |
7bb46a67 | 372 | } |
373 | EXPORT_SYMBOL(simple_setattr); | |
374 | ||
1da177e4 LT |
375 | int simple_readpage(struct file *file, struct page *page) |
376 | { | |
c0d92cbc | 377 | clear_highpage(page); |
1da177e4 LT |
378 | flush_dcache_page(page); |
379 | SetPageUptodate(page); | |
1da177e4 LT |
380 | unlock_page(page); |
381 | return 0; | |
382 | } | |
383 | ||
afddba49 NP |
384 | int simple_write_begin(struct file *file, struct address_space *mapping, |
385 | loff_t pos, unsigned len, unsigned flags, | |
386 | struct page **pagep, void **fsdata) | |
387 | { | |
388 | struct page *page; | |
389 | pgoff_t index; | |
afddba49 NP |
390 | |
391 | index = pos >> PAGE_CACHE_SHIFT; | |
afddba49 | 392 | |
54566b2c | 393 | page = grab_cache_page_write_begin(mapping, index, flags); |
afddba49 NP |
394 | if (!page) |
395 | return -ENOMEM; | |
396 | ||
397 | *pagep = page; | |
398 | ||
193cf4b9 BH |
399 | if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { |
400 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
401 | ||
402 | zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); | |
403 | } | |
404 | return 0; | |
afddba49 NP |
405 | } |
406 | ||
ad2a722f BH |
407 | /** |
408 | * simple_write_end - .write_end helper for non-block-device FSes | |
409 | * @available: See .write_end of address_space_operations | |
410 | * @file: " | |
411 | * @mapping: " | |
412 | * @pos: " | |
413 | * @len: " | |
414 | * @copied: " | |
415 | * @page: " | |
416 | * @fsdata: " | |
417 | * | |
418 | * simple_write_end does the minimum needed for updating a page after writing is | |
419 | * done. It has the same API signature as the .write_end of | |
420 | * address_space_operations vector. So it can just be set onto .write_end for | |
421 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
422 | * Block based filesystems should use generic_write_end(). | |
423 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
424 | * is not called, so a filesystem that actually does store data in .write_inode | |
425 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
426 | * case that i_size has changed. | |
427 | */ | |
afddba49 NP |
428 | int simple_write_end(struct file *file, struct address_space *mapping, |
429 | loff_t pos, unsigned len, unsigned copied, | |
430 | struct page *page, void *fsdata) | |
431 | { | |
ad2a722f BH |
432 | struct inode *inode = page->mapping->host; |
433 | loff_t last_pos = pos + copied; | |
afddba49 NP |
434 | |
435 | /* zero the stale part of the page if we did a short copy */ | |
436 | if (copied < len) { | |
ad2a722f BH |
437 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
438 | ||
439 | zero_user(page, from + copied, len - copied); | |
afddba49 NP |
440 | } |
441 | ||
ad2a722f BH |
442 | if (!PageUptodate(page)) |
443 | SetPageUptodate(page); | |
444 | /* | |
445 | * No need to use i_size_read() here, the i_size | |
446 | * cannot change under us because we hold the i_mutex. | |
447 | */ | |
448 | if (last_pos > inode->i_size) | |
449 | i_size_write(inode, last_pos); | |
afddba49 | 450 | |
ad2a722f | 451 | set_page_dirty(page); |
afddba49 NP |
452 | unlock_page(page); |
453 | page_cache_release(page); | |
454 | ||
455 | return copied; | |
456 | } | |
457 | ||
1a1c9bb4 JL |
458 | /* |
459 | * the inodes created here are not hashed. If you use iunique to generate | |
460 | * unique inode values later for this filesystem, then you must take care | |
461 | * to pass it an appropriate max_reserved value to avoid collisions. | |
462 | */ | |
7d683a09 RS |
463 | int simple_fill_super(struct super_block *s, unsigned long magic, |
464 | struct tree_descr *files) | |
1da177e4 | 465 | { |
1da177e4 LT |
466 | struct inode *inode; |
467 | struct dentry *root; | |
468 | struct dentry *dentry; | |
469 | int i; | |
470 | ||
471 | s->s_blocksize = PAGE_CACHE_SIZE; | |
472 | s->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
473 | s->s_magic = magic; | |
759b9775 | 474 | s->s_op = &simple_super_operations; |
1da177e4 LT |
475 | s->s_time_gran = 1; |
476 | ||
477 | inode = new_inode(s); | |
478 | if (!inode) | |
479 | return -ENOMEM; | |
1a1c9bb4 JL |
480 | /* |
481 | * because the root inode is 1, the files array must not contain an | |
482 | * entry at index 1 | |
483 | */ | |
484 | inode->i_ino = 1; | |
1da177e4 | 485 | inode->i_mode = S_IFDIR | 0755; |
1da177e4 LT |
486 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
487 | inode->i_op = &simple_dir_inode_operations; | |
488 | inode->i_fop = &simple_dir_operations; | |
7656f328 | 489 | inode->i_nlink = 2; |
1da177e4 LT |
490 | root = d_alloc_root(inode); |
491 | if (!root) { | |
492 | iput(inode); | |
493 | return -ENOMEM; | |
494 | } | |
495 | for (i = 0; !files->name || files->name[0]; i++, files++) { | |
496 | if (!files->name) | |
497 | continue; | |
1a1c9bb4 JL |
498 | |
499 | /* warn if it tries to conflict with the root inode */ | |
500 | if (unlikely(i == 1)) | |
501 | printk(KERN_WARNING "%s: %s passed in a files array" | |
502 | "with an index of 1!\n", __func__, | |
503 | s->s_type->name); | |
504 | ||
1da177e4 LT |
505 | dentry = d_alloc_name(root, files->name); |
506 | if (!dentry) | |
507 | goto out; | |
508 | inode = new_inode(s); | |
509 | if (!inode) | |
510 | goto out; | |
511 | inode->i_mode = S_IFREG | files->mode; | |
1da177e4 LT |
512 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
513 | inode->i_fop = files->ops; | |
514 | inode->i_ino = i; | |
515 | d_add(dentry, inode); | |
516 | } | |
517 | s->s_root = root; | |
518 | return 0; | |
519 | out: | |
520 | d_genocide(root); | |
521 | dput(root); | |
522 | return -ENOMEM; | |
523 | } | |
524 | ||
525 | static DEFINE_SPINLOCK(pin_fs_lock); | |
526 | ||
1f5ce9e9 | 527 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
528 | { |
529 | struct vfsmount *mnt = NULL; | |
530 | spin_lock(&pin_fs_lock); | |
531 | if (unlikely(!*mount)) { | |
532 | spin_unlock(&pin_fs_lock); | |
1f5ce9e9 | 533 | mnt = vfs_kern_mount(type, 0, type->name, NULL); |
1da177e4 LT |
534 | if (IS_ERR(mnt)) |
535 | return PTR_ERR(mnt); | |
536 | spin_lock(&pin_fs_lock); | |
537 | if (!*mount) | |
538 | *mount = mnt; | |
539 | } | |
540 | mntget(*mount); | |
541 | ++*count; | |
542 | spin_unlock(&pin_fs_lock); | |
543 | mntput(mnt); | |
544 | return 0; | |
545 | } | |
546 | ||
547 | void simple_release_fs(struct vfsmount **mount, int *count) | |
548 | { | |
549 | struct vfsmount *mnt; | |
550 | spin_lock(&pin_fs_lock); | |
551 | mnt = *mount; | |
552 | if (!--*count) | |
553 | *mount = NULL; | |
554 | spin_unlock(&pin_fs_lock); | |
555 | mntput(mnt); | |
556 | } | |
557 | ||
6d1029b5 AM |
558 | /** |
559 | * simple_read_from_buffer - copy data from the buffer to user space | |
560 | * @to: the user space buffer to read to | |
561 | * @count: the maximum number of bytes to read | |
562 | * @ppos: the current position in the buffer | |
563 | * @from: the buffer to read from | |
564 | * @available: the size of the buffer | |
565 | * | |
566 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
567 | * buffer @from at offset @ppos into the user space address starting at @to. | |
568 | * | |
569 | * On success, the number of bytes read is returned and the offset @ppos is | |
570 | * advanced by this number, or negative value is returned on error. | |
571 | **/ | |
1da177e4 LT |
572 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
573 | const void *from, size_t available) | |
574 | { | |
575 | loff_t pos = *ppos; | |
14be2746 SR |
576 | size_t ret; |
577 | ||
1da177e4 LT |
578 | if (pos < 0) |
579 | return -EINVAL; | |
14be2746 | 580 | if (pos >= available || !count) |
1da177e4 LT |
581 | return 0; |
582 | if (count > available - pos) | |
583 | count = available - pos; | |
14be2746 SR |
584 | ret = copy_to_user(to, from + pos, count); |
585 | if (ret == count) | |
1da177e4 | 586 | return -EFAULT; |
14be2746 | 587 | count -= ret; |
1da177e4 LT |
588 | *ppos = pos + count; |
589 | return count; | |
590 | } | |
591 | ||
6a727b43 JS |
592 | /** |
593 | * simple_write_to_buffer - copy data from user space to the buffer | |
594 | * @to: the buffer to write to | |
595 | * @available: the size of the buffer | |
596 | * @ppos: the current position in the buffer | |
597 | * @from: the user space buffer to read from | |
598 | * @count: the maximum number of bytes to read | |
599 | * | |
600 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
601 | * space address starting at @from into the buffer @to at offset @ppos. | |
602 | * | |
603 | * On success, the number of bytes written is returned and the offset @ppos is | |
604 | * advanced by this number, or negative value is returned on error. | |
605 | **/ | |
606 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
607 | const void __user *from, size_t count) | |
608 | { | |
609 | loff_t pos = *ppos; | |
610 | size_t res; | |
611 | ||
612 | if (pos < 0) | |
613 | return -EINVAL; | |
614 | if (pos >= available || !count) | |
615 | return 0; | |
616 | if (count > available - pos) | |
617 | count = available - pos; | |
618 | res = copy_from_user(to + pos, from, count); | |
619 | if (res == count) | |
620 | return -EFAULT; | |
621 | count -= res; | |
622 | *ppos = pos + count; | |
623 | return count; | |
624 | } | |
625 | ||
6d1029b5 AM |
626 | /** |
627 | * memory_read_from_buffer - copy data from the buffer | |
628 | * @to: the kernel space buffer to read to | |
629 | * @count: the maximum number of bytes to read | |
630 | * @ppos: the current position in the buffer | |
631 | * @from: the buffer to read from | |
632 | * @available: the size of the buffer | |
633 | * | |
634 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
635 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
636 | * | |
637 | * On success, the number of bytes read is returned and the offset @ppos is | |
638 | * advanced by this number, or negative value is returned on error. | |
639 | **/ | |
93b07113 AM |
640 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
641 | const void *from, size_t available) | |
642 | { | |
643 | loff_t pos = *ppos; | |
644 | ||
645 | if (pos < 0) | |
646 | return -EINVAL; | |
647 | if (pos >= available) | |
648 | return 0; | |
649 | if (count > available - pos) | |
650 | count = available - pos; | |
651 | memcpy(to, from + pos, count); | |
652 | *ppos = pos + count; | |
653 | ||
654 | return count; | |
655 | } | |
656 | ||
1da177e4 LT |
657 | /* |
658 | * Transaction based IO. | |
659 | * The file expects a single write which triggers the transaction, and then | |
660 | * possibly a read which collects the result - which is stored in a | |
661 | * file-local buffer. | |
662 | */ | |
76791ab2 IM |
663 | |
664 | void simple_transaction_set(struct file *file, size_t n) | |
665 | { | |
666 | struct simple_transaction_argresp *ar = file->private_data; | |
667 | ||
668 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
669 | ||
670 | /* | |
671 | * The barrier ensures that ar->size will really remain zero until | |
672 | * ar->data is ready for reading. | |
673 | */ | |
674 | smp_mb(); | |
675 | ar->size = n; | |
676 | } | |
677 | ||
1da177e4 LT |
678 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
679 | { | |
680 | struct simple_transaction_argresp *ar; | |
681 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
682 | ||
683 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
684 | return ERR_PTR(-EFBIG); | |
685 | ||
686 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
687 | if (!ar) | |
688 | return ERR_PTR(-ENOMEM); | |
689 | ||
690 | spin_lock(&simple_transaction_lock); | |
691 | ||
692 | /* only one write allowed per open */ | |
693 | if (file->private_data) { | |
694 | spin_unlock(&simple_transaction_lock); | |
695 | free_page((unsigned long)ar); | |
696 | return ERR_PTR(-EBUSY); | |
697 | } | |
698 | ||
699 | file->private_data = ar; | |
700 | ||
701 | spin_unlock(&simple_transaction_lock); | |
702 | ||
703 | if (copy_from_user(ar->data, buf, size)) | |
704 | return ERR_PTR(-EFAULT); | |
705 | ||
706 | return ar->data; | |
707 | } | |
708 | ||
709 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
710 | { | |
711 | struct simple_transaction_argresp *ar = file->private_data; | |
712 | ||
713 | if (!ar) | |
714 | return 0; | |
715 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
716 | } | |
717 | ||
718 | int simple_transaction_release(struct inode *inode, struct file *file) | |
719 | { | |
720 | free_page((unsigned long)file->private_data); | |
721 | return 0; | |
722 | } | |
723 | ||
acaefc25 AB |
724 | /* Simple attribute files */ |
725 | ||
726 | struct simple_attr { | |
8b88b099 CH |
727 | int (*get)(void *, u64 *); |
728 | int (*set)(void *, u64); | |
acaefc25 AB |
729 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
730 | char set_buf[24]; | |
731 | void *data; | |
732 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 733 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
734 | }; |
735 | ||
736 | /* simple_attr_open is called by an actual attribute open file operation | |
737 | * to set the attribute specific access operations. */ | |
738 | int simple_attr_open(struct inode *inode, struct file *file, | |
8b88b099 | 739 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25 AB |
740 | const char *fmt) |
741 | { | |
742 | struct simple_attr *attr; | |
743 | ||
744 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); | |
745 | if (!attr) | |
746 | return -ENOMEM; | |
747 | ||
748 | attr->get = get; | |
749 | attr->set = set; | |
8e18e294 | 750 | attr->data = inode->i_private; |
acaefc25 | 751 | attr->fmt = fmt; |
7cf34c76 | 752 | mutex_init(&attr->mutex); |
acaefc25 AB |
753 | |
754 | file->private_data = attr; | |
755 | ||
756 | return nonseekable_open(inode, file); | |
757 | } | |
758 | ||
74bedc4d | 759 | int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25 AB |
760 | { |
761 | kfree(file->private_data); | |
762 | return 0; | |
763 | } | |
764 | ||
765 | /* read from the buffer that is filled with the get function */ | |
766 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
767 | size_t len, loff_t *ppos) | |
768 | { | |
769 | struct simple_attr *attr; | |
770 | size_t size; | |
771 | ssize_t ret; | |
772 | ||
773 | attr = file->private_data; | |
774 | ||
775 | if (!attr->get) | |
776 | return -EACCES; | |
777 | ||
9261303a CH |
778 | ret = mutex_lock_interruptible(&attr->mutex); |
779 | if (ret) | |
780 | return ret; | |
781 | ||
8b88b099 | 782 | if (*ppos) { /* continued read */ |
acaefc25 | 783 | size = strlen(attr->get_buf); |
8b88b099 CH |
784 | } else { /* first read */ |
785 | u64 val; | |
786 | ret = attr->get(attr->data, &val); | |
787 | if (ret) | |
788 | goto out; | |
789 | ||
acaefc25 | 790 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b099 CH |
791 | attr->fmt, (unsigned long long)val); |
792 | } | |
acaefc25 AB |
793 | |
794 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
8b88b099 | 795 | out: |
7cf34c76 | 796 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
797 | return ret; |
798 | } | |
799 | ||
800 | /* interpret the buffer as a number to call the set function with */ | |
801 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
802 | size_t len, loff_t *ppos) | |
803 | { | |
804 | struct simple_attr *attr; | |
805 | u64 val; | |
806 | size_t size; | |
807 | ssize_t ret; | |
808 | ||
809 | attr = file->private_data; | |
acaefc25 AB |
810 | if (!attr->set) |
811 | return -EACCES; | |
812 | ||
9261303a CH |
813 | ret = mutex_lock_interruptible(&attr->mutex); |
814 | if (ret) | |
815 | return ret; | |
816 | ||
acaefc25 AB |
817 | ret = -EFAULT; |
818 | size = min(sizeof(attr->set_buf) - 1, len); | |
819 | if (copy_from_user(attr->set_buf, buf, size)) | |
820 | goto out; | |
821 | ||
acaefc25 AB |
822 | attr->set_buf[size] = '\0'; |
823 | val = simple_strtol(attr->set_buf, NULL, 0); | |
05cc0cee WF |
824 | ret = attr->set(attr->data, val); |
825 | if (ret == 0) | |
826 | ret = len; /* on success, claim we got the whole input */ | |
acaefc25 | 827 | out: |
7cf34c76 | 828 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
829 | return ret; |
830 | } | |
831 | ||
2596110a CH |
832 | /** |
833 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
834 | * @sb: filesystem to do the file handle conversion on | |
835 | * @fid: file handle to convert | |
836 | * @fh_len: length of the file handle in bytes | |
837 | * @fh_type: type of file handle | |
838 | * @get_inode: filesystem callback to retrieve inode | |
839 | * | |
840 | * This function decodes @fid as long as it has one of the well-known | |
841 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
842 | * inode for the object specified in the file handle. | |
843 | */ | |
844 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
845 | int fh_len, int fh_type, struct inode *(*get_inode) | |
846 | (struct super_block *sb, u64 ino, u32 gen)) | |
847 | { | |
848 | struct inode *inode = NULL; | |
849 | ||
850 | if (fh_len < 2) | |
851 | return NULL; | |
852 | ||
853 | switch (fh_type) { | |
854 | case FILEID_INO32_GEN: | |
855 | case FILEID_INO32_GEN_PARENT: | |
856 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
857 | break; | |
858 | } | |
859 | ||
4ea3ada2 | 860 | return d_obtain_alias(inode); |
2596110a CH |
861 | } |
862 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
863 | ||
864 | /** | |
865 | * generic_fh_to_dentry - generic helper for the fh_to_parent export operation | |
866 | * @sb: filesystem to do the file handle conversion on | |
867 | * @fid: file handle to convert | |
868 | * @fh_len: length of the file handle in bytes | |
869 | * @fh_type: type of file handle | |
870 | * @get_inode: filesystem callback to retrieve inode | |
871 | * | |
872 | * This function decodes @fid as long as it has one of the well-known | |
873 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
874 | * inode for the _parent_ object specified in the file handle if it | |
875 | * is specified in the file handle, or NULL otherwise. | |
876 | */ | |
877 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
878 | int fh_len, int fh_type, struct inode *(*get_inode) | |
879 | (struct super_block *sb, u64 ino, u32 gen)) | |
880 | { | |
881 | struct inode *inode = NULL; | |
882 | ||
883 | if (fh_len <= 2) | |
884 | return NULL; | |
885 | ||
886 | switch (fh_type) { | |
887 | case FILEID_INO32_GEN_PARENT: | |
888 | inode = get_inode(sb, fid->i32.parent_ino, | |
889 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
890 | break; | |
891 | } | |
892 | ||
4ea3ada2 | 893 | return d_obtain_alias(inode); |
2596110a CH |
894 | } |
895 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
896 | ||
1b061d92 CH |
897 | /** |
898 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
899 | * @file: file to synchronize | |
900 | * @datasync: only synchronize essential metadata if true | |
901 | * | |
902 | * This is a generic implementation of the fsync method for simple | |
903 | * filesystems which track all non-inode metadata in the buffers list | |
904 | * hanging off the address_space structure. | |
905 | */ | |
906 | int generic_file_fsync(struct file *file, int datasync) | |
d5aacad5 | 907 | { |
7ea80859 | 908 | struct inode *inode = file->f_mapping->host; |
d5aacad5 AV |
909 | int err; |
910 | int ret; | |
911 | ||
912 | ret = sync_mapping_buffers(inode->i_mapping); | |
913 | if (!(inode->i_state & I_DIRTY)) | |
914 | return ret; | |
915 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) | |
916 | return ret; | |
917 | ||
c3765016 | 918 | err = sync_inode_metadata(inode, 1); |
d5aacad5 AV |
919 | if (ret == 0) |
920 | ret = err; | |
921 | return ret; | |
922 | } | |
1b061d92 CH |
923 | EXPORT_SYMBOL(generic_file_fsync); |
924 | ||
30ca22c7 PL |
925 | /** |
926 | * generic_check_addressable - Check addressability of file system | |
927 | * @blocksize_bits: log of file system block size | |
928 | * @num_blocks: number of blocks in file system | |
929 | * | |
930 | * Determine whether a file system with @num_blocks blocks (and a | |
931 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
932 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
933 | */ | |
934 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
935 | { | |
936 | u64 last_fs_block = num_blocks - 1; | |
a33f13ef JB |
937 | u64 last_fs_page = |
938 | last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); | |
30ca22c7 PL |
939 | |
940 | if (unlikely(num_blocks == 0)) | |
941 | return 0; | |
942 | ||
943 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) | |
944 | return -EINVAL; | |
945 | ||
a33f13ef JB |
946 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
947 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
30ca22c7 PL |
948 | return -EFBIG; |
949 | } | |
950 | return 0; | |
951 | } | |
952 | EXPORT_SYMBOL(generic_check_addressable); | |
953 | ||
1b061d92 CH |
954 | /* |
955 | * No-op implementation of ->fsync for in-memory filesystems. | |
956 | */ | |
957 | int noop_fsync(struct file *file, int datasync) | |
958 | { | |
959 | return 0; | |
960 | } | |
d5aacad5 | 961 | |
1da177e4 LT |
962 | EXPORT_SYMBOL(dcache_dir_close); |
963 | EXPORT_SYMBOL(dcache_dir_lseek); | |
964 | EXPORT_SYMBOL(dcache_dir_open); | |
965 | EXPORT_SYMBOL(dcache_readdir); | |
966 | EXPORT_SYMBOL(generic_read_dir); | |
51139ada | 967 | EXPORT_SYMBOL(mount_pseudo); |
afddba49 NP |
968 | EXPORT_SYMBOL(simple_write_begin); |
969 | EXPORT_SYMBOL(simple_write_end); | |
1da177e4 LT |
970 | EXPORT_SYMBOL(simple_dir_inode_operations); |
971 | EXPORT_SYMBOL(simple_dir_operations); | |
972 | EXPORT_SYMBOL(simple_empty); | |
1da177e4 LT |
973 | EXPORT_SYMBOL(simple_fill_super); |
974 | EXPORT_SYMBOL(simple_getattr); | |
975 | EXPORT_SYMBOL(simple_link); | |
976 | EXPORT_SYMBOL(simple_lookup); | |
977 | EXPORT_SYMBOL(simple_pin_fs); | |
1da177e4 LT |
978 | EXPORT_SYMBOL(simple_readpage); |
979 | EXPORT_SYMBOL(simple_release_fs); | |
980 | EXPORT_SYMBOL(simple_rename); | |
981 | EXPORT_SYMBOL(simple_rmdir); | |
982 | EXPORT_SYMBOL(simple_statfs); | |
1b061d92 | 983 | EXPORT_SYMBOL(noop_fsync); |
1da177e4 LT |
984 | EXPORT_SYMBOL(simple_unlink); |
985 | EXPORT_SYMBOL(simple_read_from_buffer); | |
6a727b43 | 986 | EXPORT_SYMBOL(simple_write_to_buffer); |
93b07113 | 987 | EXPORT_SYMBOL(memory_read_from_buffer); |
76791ab2 | 988 | EXPORT_SYMBOL(simple_transaction_set); |
1da177e4 LT |
989 | EXPORT_SYMBOL(simple_transaction_get); |
990 | EXPORT_SYMBOL(simple_transaction_read); | |
991 | EXPORT_SYMBOL(simple_transaction_release); | |
acaefc25 | 992 | EXPORT_SYMBOL_GPL(simple_attr_open); |
74bedc4d | 993 | EXPORT_SYMBOL_GPL(simple_attr_release); |
acaefc25 AB |
994 | EXPORT_SYMBOL_GPL(simple_attr_read); |
995 | EXPORT_SYMBOL_GPL(simple_attr_write); |