Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/libfs.c | |
3 | * Library for filesystems writers. | |
4 | */ | |
5 | ||
630d9c47 | 6 | #include <linux/export.h> |
1da177e4 | 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 | 14 | #include <linux/writeback.h> |
ff01bb48 | 15 | #include <linux/buffer_head.h> /* sync_mapping_buffers */ |
7cf34c76 | 16 | |
1da177e4 LT |
17 | #include <asm/uaccess.h> |
18 | ||
a4464dbc AV |
19 | #include "internal.h" |
20 | ||
da502956 NP |
21 | static inline int simple_positive(struct dentry *dentry) |
22 | { | |
23 | return dentry->d_inode && !d_unhashed(dentry); | |
24 | } | |
25 | ||
1da177e4 LT |
26 | int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, |
27 | struct kstat *stat) | |
28 | { | |
29 | struct inode *inode = dentry->d_inode; | |
30 | generic_fillattr(inode, stat); | |
31 | stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); | |
32 | return 0; | |
33 | } | |
34 | ||
726c3342 | 35 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 36 | { |
726c3342 | 37 | buf->f_type = dentry->d_sb->s_magic; |
1da177e4 LT |
38 | buf->f_bsize = PAGE_CACHE_SIZE; |
39 | buf->f_namelen = NAME_MAX; | |
40 | return 0; | |
41 | } | |
42 | ||
43 | /* | |
44 | * Retaining negative dentries for an in-memory filesystem just wastes | |
45 | * memory and lookup time: arrange for them to be deleted immediately. | |
46 | */ | |
fe15ce44 | 47 | static int simple_delete_dentry(const struct dentry *dentry) |
1da177e4 LT |
48 | { |
49 | return 1; | |
50 | } | |
51 | ||
52 | /* | |
53 | * Lookup the data. This is trivial - if the dentry didn't already | |
54 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
55 | */ | |
00cd8dd3 | 56 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 | 57 | { |
3ba13d17 | 58 | static const struct dentry_operations simple_dentry_operations = { |
1da177e4 LT |
59 | .d_delete = simple_delete_dentry, |
60 | }; | |
61 | ||
62 | if (dentry->d_name.len > NAME_MAX) | |
63 | return ERR_PTR(-ENAMETOOLONG); | |
fb045adb | 64 | d_set_d_op(dentry, &simple_dentry_operations); |
1da177e4 LT |
65 | d_add(dentry, NULL); |
66 | return NULL; | |
67 | } | |
68 | ||
1da177e4 LT |
69 | int dcache_dir_open(struct inode *inode, struct file *file) |
70 | { | |
26fe5750 | 71 | static struct qstr cursor_name = QSTR_INIT(".", 1); |
1da177e4 | 72 | |
0f7fc9e4 | 73 | file->private_data = d_alloc(file->f_path.dentry, &cursor_name); |
1da177e4 LT |
74 | |
75 | return file->private_data ? 0 : -ENOMEM; | |
76 | } | |
77 | ||
78 | int dcache_dir_close(struct inode *inode, struct file *file) | |
79 | { | |
80 | dput(file->private_data); | |
81 | return 0; | |
82 | } | |
83 | ||
965c8e59 | 84 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 85 | { |
2fd6b7f5 NP |
86 | struct dentry *dentry = file->f_path.dentry; |
87 | mutex_lock(&dentry->d_inode->i_mutex); | |
965c8e59 | 88 | switch (whence) { |
1da177e4 LT |
89 | case 1: |
90 | offset += file->f_pos; | |
91 | case 0: | |
92 | if (offset >= 0) | |
93 | break; | |
94 | default: | |
2fd6b7f5 | 95 | mutex_unlock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
96 | return -EINVAL; |
97 | } | |
98 | if (offset != file->f_pos) { | |
99 | file->f_pos = offset; | |
100 | if (file->f_pos >= 2) { | |
101 | struct list_head *p; | |
102 | struct dentry *cursor = file->private_data; | |
103 | loff_t n = file->f_pos - 2; | |
104 | ||
2fd6b7f5 NP |
105 | spin_lock(&dentry->d_lock); |
106 | /* d_lock not required for cursor */ | |
5160ee6f | 107 | list_del(&cursor->d_u.d_child); |
2fd6b7f5 NP |
108 | p = dentry->d_subdirs.next; |
109 | while (n && p != &dentry->d_subdirs) { | |
1da177e4 | 110 | struct dentry *next; |
5160ee6f | 111 | next = list_entry(p, struct dentry, d_u.d_child); |
2fd6b7f5 | 112 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); |
da502956 | 113 | if (simple_positive(next)) |
1da177e4 | 114 | n--; |
da502956 | 115 | spin_unlock(&next->d_lock); |
1da177e4 LT |
116 | p = p->next; |
117 | } | |
5160ee6f | 118 | list_add_tail(&cursor->d_u.d_child, p); |
2fd6b7f5 | 119 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
120 | } |
121 | } | |
2fd6b7f5 | 122 | mutex_unlock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
123 | return offset; |
124 | } | |
125 | ||
126 | /* Relationship between i_mode and the DT_xxx types */ | |
127 | static inline unsigned char dt_type(struct inode *inode) | |
128 | { | |
129 | return (inode->i_mode >> 12) & 15; | |
130 | } | |
131 | ||
132 | /* | |
133 | * Directory is locked and all positive dentries in it are safe, since | |
134 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
135 | * both impossible due to the lock on directory. | |
136 | */ | |
137 | ||
5f99f4e7 | 138 | int dcache_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 139 | { |
5f99f4e7 AV |
140 | struct dentry *dentry = file->f_path.dentry; |
141 | struct dentry *cursor = file->private_data; | |
5160ee6f | 142 | struct list_head *p, *q = &cursor->d_u.d_child; |
1da177e4 | 143 | |
5f99f4e7 AV |
144 | if (!dir_emit_dots(file, ctx)) |
145 | return 0; | |
146 | spin_lock(&dentry->d_lock); | |
147 | if (ctx->pos == 2) | |
148 | list_move(q, &dentry->d_subdirs); | |
149 | ||
150 | for (p = q->next; p != &dentry->d_subdirs; p = p->next) { | |
151 | struct dentry *next = list_entry(p, struct dentry, d_u.d_child); | |
152 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); | |
153 | if (!simple_positive(next)) { | |
154 | spin_unlock(&next->d_lock); | |
155 | continue; | |
156 | } | |
1da177e4 | 157 | |
5f99f4e7 AV |
158 | spin_unlock(&next->d_lock); |
159 | spin_unlock(&dentry->d_lock); | |
160 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, | |
161 | next->d_inode->i_ino, dt_type(next->d_inode))) | |
162 | return 0; | |
163 | spin_lock(&dentry->d_lock); | |
164 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); | |
165 | /* next is still alive */ | |
166 | list_move(q, p); | |
167 | spin_unlock(&next->d_lock); | |
168 | p = q; | |
169 | ctx->pos++; | |
1da177e4 | 170 | } |
5f99f4e7 | 171 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
172 | return 0; |
173 | } | |
174 | ||
175 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
176 | { | |
177 | return -EISDIR; | |
178 | } | |
179 | ||
4b6f5d20 | 180 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
181 | .open = dcache_dir_open, |
182 | .release = dcache_dir_close, | |
183 | .llseek = dcache_dir_lseek, | |
184 | .read = generic_read_dir, | |
5f99f4e7 | 185 | .iterate = dcache_readdir, |
1b061d92 | 186 | .fsync = noop_fsync, |
1da177e4 LT |
187 | }; |
188 | ||
92e1d5be | 189 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
190 | .lookup = simple_lookup, |
191 | }; | |
192 | ||
759b9775 HD |
193 | static const struct super_operations simple_super_operations = { |
194 | .statfs = simple_statfs, | |
195 | }; | |
196 | ||
1da177e4 LT |
197 | /* |
198 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
199 | * will never be mountable) | |
200 | */ | |
51139ada | 201 | struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, |
c74a1cbb AV |
202 | const struct super_operations *ops, |
203 | const struct dentry_operations *dops, unsigned long magic) | |
1da177e4 | 204 | { |
9249e17f | 205 | struct super_block *s; |
1da177e4 LT |
206 | struct dentry *dentry; |
207 | struct inode *root; | |
26fe5750 | 208 | struct qstr d_name = QSTR_INIT(name, strlen(name)); |
1da177e4 | 209 | |
9249e17f | 210 | s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); |
1da177e4 | 211 | if (IS_ERR(s)) |
51139ada | 212 | return ERR_CAST(s); |
1da177e4 | 213 | |
89a4eb4b | 214 | s->s_maxbytes = MAX_LFS_FILESIZE; |
3971e1a9 AN |
215 | s->s_blocksize = PAGE_SIZE; |
216 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 217 | s->s_magic = magic; |
759b9775 | 218 | s->s_op = ops ? ops : &simple_super_operations; |
1da177e4 LT |
219 | s->s_time_gran = 1; |
220 | root = new_inode(s); | |
221 | if (!root) | |
222 | goto Enomem; | |
1a1c9bb4 JL |
223 | /* |
224 | * since this is the first inode, make it number 1. New inodes created | |
225 | * after this must take care not to collide with it (by passing | |
226 | * max_reserved of 1 to iunique). | |
227 | */ | |
228 | root->i_ino = 1; | |
1da177e4 | 229 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
1da177e4 | 230 | root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; |
a4464dbc | 231 | dentry = __d_alloc(s, &d_name); |
1da177e4 LT |
232 | if (!dentry) { |
233 | iput(root); | |
234 | goto Enomem; | |
235 | } | |
1da177e4 LT |
236 | d_instantiate(dentry, root); |
237 | s->s_root = dentry; | |
c74a1cbb | 238 | s->s_d_op = dops; |
1da177e4 | 239 | s->s_flags |= MS_ACTIVE; |
51139ada | 240 | return dget(s->s_root); |
1da177e4 LT |
241 | |
242 | Enomem: | |
6f5bbff9 | 243 | deactivate_locked_super(s); |
51139ada | 244 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
245 | } |
246 | ||
20955e89 SB |
247 | int simple_open(struct inode *inode, struct file *file) |
248 | { | |
249 | if (inode->i_private) | |
250 | file->private_data = inode->i_private; | |
251 | return 0; | |
252 | } | |
253 | ||
1da177e4 LT |
254 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
255 | { | |
256 | struct inode *inode = old_dentry->d_inode; | |
257 | ||
258 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 259 | inc_nlink(inode); |
7de9c6ee | 260 | ihold(inode); |
1da177e4 LT |
261 | dget(dentry); |
262 | d_instantiate(dentry, inode); | |
263 | return 0; | |
264 | } | |
265 | ||
1da177e4 LT |
266 | int simple_empty(struct dentry *dentry) |
267 | { | |
268 | struct dentry *child; | |
269 | int ret = 0; | |
270 | ||
2fd6b7f5 | 271 | spin_lock(&dentry->d_lock); |
da502956 NP |
272 | list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) { |
273 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); | |
274 | if (simple_positive(child)) { | |
275 | spin_unlock(&child->d_lock); | |
1da177e4 | 276 | goto out; |
da502956 NP |
277 | } |
278 | spin_unlock(&child->d_lock); | |
279 | } | |
1da177e4 LT |
280 | ret = 1; |
281 | out: | |
2fd6b7f5 | 282 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
283 | return ret; |
284 | } | |
285 | ||
286 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
287 | { | |
288 | struct inode *inode = dentry->d_inode; | |
289 | ||
290 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 291 | drop_nlink(inode); |
1da177e4 LT |
292 | dput(dentry); |
293 | return 0; | |
294 | } | |
295 | ||
296 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
297 | { | |
298 | if (!simple_empty(dentry)) | |
299 | return -ENOTEMPTY; | |
300 | ||
9a53c3a7 | 301 | drop_nlink(dentry->d_inode); |
1da177e4 | 302 | simple_unlink(dir, dentry); |
9a53c3a7 | 303 | drop_nlink(dir); |
1da177e4 LT |
304 | return 0; |
305 | } | |
306 | ||
307 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, | |
308 | struct inode *new_dir, struct dentry *new_dentry) | |
309 | { | |
310 | struct inode *inode = old_dentry->d_inode; | |
311 | int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); | |
312 | ||
313 | if (!simple_empty(new_dentry)) | |
314 | return -ENOTEMPTY; | |
315 | ||
316 | if (new_dentry->d_inode) { | |
317 | simple_unlink(new_dir, new_dentry); | |
841590ce AV |
318 | if (they_are_dirs) { |
319 | drop_nlink(new_dentry->d_inode); | |
9a53c3a7 | 320 | drop_nlink(old_dir); |
841590ce | 321 | } |
1da177e4 | 322 | } else if (they_are_dirs) { |
9a53c3a7 | 323 | drop_nlink(old_dir); |
d8c76e6f | 324 | inc_nlink(new_dir); |
1da177e4 LT |
325 | } |
326 | ||
327 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = | |
328 | new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; | |
329 | ||
330 | return 0; | |
331 | } | |
332 | ||
7bb46a67 | 333 | /** |
eef2380c | 334 | * simple_setattr - setattr for simple filesystem |
7bb46a67 | 335 | * @dentry: dentry |
336 | * @iattr: iattr structure | |
337 | * | |
338 | * Returns 0 on success, -error on failure. | |
339 | * | |
eef2380c CH |
340 | * simple_setattr is a simple ->setattr implementation without a proper |
341 | * implementation of size changes. | |
342 | * | |
343 | * It can either be used for in-memory filesystems or special files | |
344 | * on simple regular filesystems. Anything that needs to change on-disk | |
345 | * or wire state on size changes needs its own setattr method. | |
7bb46a67 | 346 | */ |
347 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) | |
348 | { | |
349 | struct inode *inode = dentry->d_inode; | |
350 | int error; | |
351 | ||
352 | error = inode_change_ok(inode, iattr); | |
353 | if (error) | |
354 | return error; | |
355 | ||
2c27c65e CH |
356 | if (iattr->ia_valid & ATTR_SIZE) |
357 | truncate_setsize(inode, iattr->ia_size); | |
6a1a90ad | 358 | setattr_copy(inode, iattr); |
eef2380c CH |
359 | mark_inode_dirty(inode); |
360 | return 0; | |
7bb46a67 | 361 | } |
362 | EXPORT_SYMBOL(simple_setattr); | |
363 | ||
1da177e4 LT |
364 | int simple_readpage(struct file *file, struct page *page) |
365 | { | |
c0d92cbc | 366 | clear_highpage(page); |
1da177e4 LT |
367 | flush_dcache_page(page); |
368 | SetPageUptodate(page); | |
1da177e4 LT |
369 | unlock_page(page); |
370 | return 0; | |
371 | } | |
372 | ||
afddba49 NP |
373 | int simple_write_begin(struct file *file, struct address_space *mapping, |
374 | loff_t pos, unsigned len, unsigned flags, | |
375 | struct page **pagep, void **fsdata) | |
376 | { | |
377 | struct page *page; | |
378 | pgoff_t index; | |
afddba49 NP |
379 | |
380 | index = pos >> PAGE_CACHE_SHIFT; | |
afddba49 | 381 | |
54566b2c | 382 | page = grab_cache_page_write_begin(mapping, index, flags); |
afddba49 NP |
383 | if (!page) |
384 | return -ENOMEM; | |
385 | ||
386 | *pagep = page; | |
387 | ||
193cf4b9 BH |
388 | if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { |
389 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
390 | ||
391 | zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); | |
392 | } | |
393 | return 0; | |
afddba49 NP |
394 | } |
395 | ||
ad2a722f BH |
396 | /** |
397 | * simple_write_end - .write_end helper for non-block-device FSes | |
398 | * @available: See .write_end of address_space_operations | |
399 | * @file: " | |
400 | * @mapping: " | |
401 | * @pos: " | |
402 | * @len: " | |
403 | * @copied: " | |
404 | * @page: " | |
405 | * @fsdata: " | |
406 | * | |
407 | * simple_write_end does the minimum needed for updating a page after writing is | |
408 | * done. It has the same API signature as the .write_end of | |
409 | * address_space_operations vector. So it can just be set onto .write_end for | |
410 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
411 | * Block based filesystems should use generic_write_end(). | |
412 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
413 | * is not called, so a filesystem that actually does store data in .write_inode | |
414 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
415 | * case that i_size has changed. | |
416 | */ | |
afddba49 NP |
417 | int simple_write_end(struct file *file, struct address_space *mapping, |
418 | loff_t pos, unsigned len, unsigned copied, | |
419 | struct page *page, void *fsdata) | |
420 | { | |
ad2a722f BH |
421 | struct inode *inode = page->mapping->host; |
422 | loff_t last_pos = pos + copied; | |
afddba49 NP |
423 | |
424 | /* zero the stale part of the page if we did a short copy */ | |
425 | if (copied < len) { | |
ad2a722f BH |
426 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
427 | ||
428 | zero_user(page, from + copied, len - copied); | |
afddba49 NP |
429 | } |
430 | ||
ad2a722f BH |
431 | if (!PageUptodate(page)) |
432 | SetPageUptodate(page); | |
433 | /* | |
434 | * No need to use i_size_read() here, the i_size | |
435 | * cannot change under us because we hold the i_mutex. | |
436 | */ | |
437 | if (last_pos > inode->i_size) | |
438 | i_size_write(inode, last_pos); | |
afddba49 | 439 | |
ad2a722f | 440 | set_page_dirty(page); |
afddba49 NP |
441 | unlock_page(page); |
442 | page_cache_release(page); | |
443 | ||
444 | return copied; | |
445 | } | |
446 | ||
1a1c9bb4 JL |
447 | /* |
448 | * the inodes created here are not hashed. If you use iunique to generate | |
449 | * unique inode values later for this filesystem, then you must take care | |
450 | * to pass it an appropriate max_reserved value to avoid collisions. | |
451 | */ | |
7d683a09 RS |
452 | int simple_fill_super(struct super_block *s, unsigned long magic, |
453 | struct tree_descr *files) | |
1da177e4 | 454 | { |
1da177e4 LT |
455 | struct inode *inode; |
456 | struct dentry *root; | |
457 | struct dentry *dentry; | |
458 | int i; | |
459 | ||
460 | s->s_blocksize = PAGE_CACHE_SIZE; | |
461 | s->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
462 | s->s_magic = magic; | |
759b9775 | 463 | s->s_op = &simple_super_operations; |
1da177e4 LT |
464 | s->s_time_gran = 1; |
465 | ||
466 | inode = new_inode(s); | |
467 | if (!inode) | |
468 | return -ENOMEM; | |
1a1c9bb4 JL |
469 | /* |
470 | * because the root inode is 1, the files array must not contain an | |
471 | * entry at index 1 | |
472 | */ | |
473 | inode->i_ino = 1; | |
1da177e4 | 474 | inode->i_mode = S_IFDIR | 0755; |
1da177e4 LT |
475 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
476 | inode->i_op = &simple_dir_inode_operations; | |
477 | inode->i_fop = &simple_dir_operations; | |
bfe86848 | 478 | set_nlink(inode, 2); |
48fde701 AV |
479 | root = d_make_root(inode); |
480 | if (!root) | |
1da177e4 | 481 | return -ENOMEM; |
1da177e4 LT |
482 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
483 | if (!files->name) | |
484 | continue; | |
1a1c9bb4 JL |
485 | |
486 | /* warn if it tries to conflict with the root inode */ | |
487 | if (unlikely(i == 1)) | |
488 | printk(KERN_WARNING "%s: %s passed in a files array" | |
489 | "with an index of 1!\n", __func__, | |
490 | s->s_type->name); | |
491 | ||
1da177e4 LT |
492 | dentry = d_alloc_name(root, files->name); |
493 | if (!dentry) | |
494 | goto out; | |
495 | inode = new_inode(s); | |
32096ea1 KK |
496 | if (!inode) { |
497 | dput(dentry); | |
1da177e4 | 498 | goto out; |
32096ea1 | 499 | } |
1da177e4 | 500 | inode->i_mode = S_IFREG | files->mode; |
1da177e4 LT |
501 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
502 | inode->i_fop = files->ops; | |
503 | inode->i_ino = i; | |
504 | d_add(dentry, inode); | |
505 | } | |
506 | s->s_root = root; | |
507 | return 0; | |
508 | out: | |
509 | d_genocide(root); | |
640946f2 | 510 | shrink_dcache_parent(root); |
1da177e4 LT |
511 | dput(root); |
512 | return -ENOMEM; | |
513 | } | |
514 | ||
515 | static DEFINE_SPINLOCK(pin_fs_lock); | |
516 | ||
1f5ce9e9 | 517 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
518 | { |
519 | struct vfsmount *mnt = NULL; | |
520 | spin_lock(&pin_fs_lock); | |
521 | if (unlikely(!*mount)) { | |
522 | spin_unlock(&pin_fs_lock); | |
2452992a | 523 | mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); |
1da177e4 LT |
524 | if (IS_ERR(mnt)) |
525 | return PTR_ERR(mnt); | |
526 | spin_lock(&pin_fs_lock); | |
527 | if (!*mount) | |
528 | *mount = mnt; | |
529 | } | |
530 | mntget(*mount); | |
531 | ++*count; | |
532 | spin_unlock(&pin_fs_lock); | |
533 | mntput(mnt); | |
534 | return 0; | |
535 | } | |
536 | ||
537 | void simple_release_fs(struct vfsmount **mount, int *count) | |
538 | { | |
539 | struct vfsmount *mnt; | |
540 | spin_lock(&pin_fs_lock); | |
541 | mnt = *mount; | |
542 | if (!--*count) | |
543 | *mount = NULL; | |
544 | spin_unlock(&pin_fs_lock); | |
545 | mntput(mnt); | |
546 | } | |
547 | ||
6d1029b5 AM |
548 | /** |
549 | * simple_read_from_buffer - copy data from the buffer to user space | |
550 | * @to: the user space buffer to read to | |
551 | * @count: the maximum number of bytes to read | |
552 | * @ppos: the current position in the buffer | |
553 | * @from: the buffer to read from | |
554 | * @available: the size of the buffer | |
555 | * | |
556 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
557 | * buffer @from at offset @ppos into the user space address starting at @to. | |
558 | * | |
559 | * On success, the number of bytes read is returned and the offset @ppos is | |
560 | * advanced by this number, or negative value is returned on error. | |
561 | **/ | |
1da177e4 LT |
562 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
563 | const void *from, size_t available) | |
564 | { | |
565 | loff_t pos = *ppos; | |
14be2746 SR |
566 | size_t ret; |
567 | ||
1da177e4 LT |
568 | if (pos < 0) |
569 | return -EINVAL; | |
14be2746 | 570 | if (pos >= available || !count) |
1da177e4 LT |
571 | return 0; |
572 | if (count > available - pos) | |
573 | count = available - pos; | |
14be2746 SR |
574 | ret = copy_to_user(to, from + pos, count); |
575 | if (ret == count) | |
1da177e4 | 576 | return -EFAULT; |
14be2746 | 577 | count -= ret; |
1da177e4 LT |
578 | *ppos = pos + count; |
579 | return count; | |
580 | } | |
581 | ||
6a727b43 JS |
582 | /** |
583 | * simple_write_to_buffer - copy data from user space to the buffer | |
584 | * @to: the buffer to write to | |
585 | * @available: the size of the buffer | |
586 | * @ppos: the current position in the buffer | |
587 | * @from: the user space buffer to read from | |
588 | * @count: the maximum number of bytes to read | |
589 | * | |
590 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
591 | * space address starting at @from into the buffer @to at offset @ppos. | |
592 | * | |
593 | * On success, the number of bytes written is returned and the offset @ppos is | |
594 | * advanced by this number, or negative value is returned on error. | |
595 | **/ | |
596 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
597 | const void __user *from, size_t count) | |
598 | { | |
599 | loff_t pos = *ppos; | |
600 | size_t res; | |
601 | ||
602 | if (pos < 0) | |
603 | return -EINVAL; | |
604 | if (pos >= available || !count) | |
605 | return 0; | |
606 | if (count > available - pos) | |
607 | count = available - pos; | |
608 | res = copy_from_user(to + pos, from, count); | |
609 | if (res == count) | |
610 | return -EFAULT; | |
611 | count -= res; | |
612 | *ppos = pos + count; | |
613 | return count; | |
614 | } | |
615 | ||
6d1029b5 AM |
616 | /** |
617 | * memory_read_from_buffer - copy data from the buffer | |
618 | * @to: the kernel space buffer to read to | |
619 | * @count: the maximum number of bytes to read | |
620 | * @ppos: the current position in the buffer | |
621 | * @from: the buffer to read from | |
622 | * @available: the size of the buffer | |
623 | * | |
624 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
625 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
626 | * | |
627 | * On success, the number of bytes read is returned and the offset @ppos is | |
628 | * advanced by this number, or negative value is returned on error. | |
629 | **/ | |
93b07113 AM |
630 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
631 | const void *from, size_t available) | |
632 | { | |
633 | loff_t pos = *ppos; | |
634 | ||
635 | if (pos < 0) | |
636 | return -EINVAL; | |
637 | if (pos >= available) | |
638 | return 0; | |
639 | if (count > available - pos) | |
640 | count = available - pos; | |
641 | memcpy(to, from + pos, count); | |
642 | *ppos = pos + count; | |
643 | ||
644 | return count; | |
645 | } | |
646 | ||
1da177e4 LT |
647 | /* |
648 | * Transaction based IO. | |
649 | * The file expects a single write which triggers the transaction, and then | |
650 | * possibly a read which collects the result - which is stored in a | |
651 | * file-local buffer. | |
652 | */ | |
76791ab2 IM |
653 | |
654 | void simple_transaction_set(struct file *file, size_t n) | |
655 | { | |
656 | struct simple_transaction_argresp *ar = file->private_data; | |
657 | ||
658 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
659 | ||
660 | /* | |
661 | * The barrier ensures that ar->size will really remain zero until | |
662 | * ar->data is ready for reading. | |
663 | */ | |
664 | smp_mb(); | |
665 | ar->size = n; | |
666 | } | |
667 | ||
1da177e4 LT |
668 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
669 | { | |
670 | struct simple_transaction_argresp *ar; | |
671 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
672 | ||
673 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
674 | return ERR_PTR(-EFBIG); | |
675 | ||
676 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
677 | if (!ar) | |
678 | return ERR_PTR(-ENOMEM); | |
679 | ||
680 | spin_lock(&simple_transaction_lock); | |
681 | ||
682 | /* only one write allowed per open */ | |
683 | if (file->private_data) { | |
684 | spin_unlock(&simple_transaction_lock); | |
685 | free_page((unsigned long)ar); | |
686 | return ERR_PTR(-EBUSY); | |
687 | } | |
688 | ||
689 | file->private_data = ar; | |
690 | ||
691 | spin_unlock(&simple_transaction_lock); | |
692 | ||
693 | if (copy_from_user(ar->data, buf, size)) | |
694 | return ERR_PTR(-EFAULT); | |
695 | ||
696 | return ar->data; | |
697 | } | |
698 | ||
699 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
700 | { | |
701 | struct simple_transaction_argresp *ar = file->private_data; | |
702 | ||
703 | if (!ar) | |
704 | return 0; | |
705 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
706 | } | |
707 | ||
708 | int simple_transaction_release(struct inode *inode, struct file *file) | |
709 | { | |
710 | free_page((unsigned long)file->private_data); | |
711 | return 0; | |
712 | } | |
713 | ||
acaefc25 AB |
714 | /* Simple attribute files */ |
715 | ||
716 | struct simple_attr { | |
8b88b099 CH |
717 | int (*get)(void *, u64 *); |
718 | int (*set)(void *, u64); | |
acaefc25 AB |
719 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
720 | char set_buf[24]; | |
721 | void *data; | |
722 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 723 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
724 | }; |
725 | ||
726 | /* simple_attr_open is called by an actual attribute open file operation | |
727 | * to set the attribute specific access operations. */ | |
728 | int simple_attr_open(struct inode *inode, struct file *file, | |
8b88b099 | 729 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25 AB |
730 | const char *fmt) |
731 | { | |
732 | struct simple_attr *attr; | |
733 | ||
734 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); | |
735 | if (!attr) | |
736 | return -ENOMEM; | |
737 | ||
738 | attr->get = get; | |
739 | attr->set = set; | |
8e18e294 | 740 | attr->data = inode->i_private; |
acaefc25 | 741 | attr->fmt = fmt; |
7cf34c76 | 742 | mutex_init(&attr->mutex); |
acaefc25 AB |
743 | |
744 | file->private_data = attr; | |
745 | ||
746 | return nonseekable_open(inode, file); | |
747 | } | |
748 | ||
74bedc4d | 749 | int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25 AB |
750 | { |
751 | kfree(file->private_data); | |
752 | return 0; | |
753 | } | |
754 | ||
755 | /* read from the buffer that is filled with the get function */ | |
756 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
757 | size_t len, loff_t *ppos) | |
758 | { | |
759 | struct simple_attr *attr; | |
760 | size_t size; | |
761 | ssize_t ret; | |
762 | ||
763 | attr = file->private_data; | |
764 | ||
765 | if (!attr->get) | |
766 | return -EACCES; | |
767 | ||
9261303a CH |
768 | ret = mutex_lock_interruptible(&attr->mutex); |
769 | if (ret) | |
770 | return ret; | |
771 | ||
8b88b099 | 772 | if (*ppos) { /* continued read */ |
acaefc25 | 773 | size = strlen(attr->get_buf); |
8b88b099 CH |
774 | } else { /* first read */ |
775 | u64 val; | |
776 | ret = attr->get(attr->data, &val); | |
777 | if (ret) | |
778 | goto out; | |
779 | ||
acaefc25 | 780 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b099 CH |
781 | attr->fmt, (unsigned long long)val); |
782 | } | |
acaefc25 AB |
783 | |
784 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
8b88b099 | 785 | out: |
7cf34c76 | 786 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
787 | return ret; |
788 | } | |
789 | ||
790 | /* interpret the buffer as a number to call the set function with */ | |
791 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
792 | size_t len, loff_t *ppos) | |
793 | { | |
794 | struct simple_attr *attr; | |
795 | u64 val; | |
796 | size_t size; | |
797 | ssize_t ret; | |
798 | ||
799 | attr = file->private_data; | |
acaefc25 AB |
800 | if (!attr->set) |
801 | return -EACCES; | |
802 | ||
9261303a CH |
803 | ret = mutex_lock_interruptible(&attr->mutex); |
804 | if (ret) | |
805 | return ret; | |
806 | ||
acaefc25 AB |
807 | ret = -EFAULT; |
808 | size = min(sizeof(attr->set_buf) - 1, len); | |
809 | if (copy_from_user(attr->set_buf, buf, size)) | |
810 | goto out; | |
811 | ||
acaefc25 | 812 | attr->set_buf[size] = '\0'; |
f7b88631 | 813 | val = simple_strtoll(attr->set_buf, NULL, 0); |
05cc0cee WF |
814 | ret = attr->set(attr->data, val); |
815 | if (ret == 0) | |
816 | ret = len; /* on success, claim we got the whole input */ | |
acaefc25 | 817 | out: |
7cf34c76 | 818 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
819 | return ret; |
820 | } | |
821 | ||
2596110a CH |
822 | /** |
823 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
824 | * @sb: filesystem to do the file handle conversion on | |
825 | * @fid: file handle to convert | |
826 | * @fh_len: length of the file handle in bytes | |
827 | * @fh_type: type of file handle | |
828 | * @get_inode: filesystem callback to retrieve inode | |
829 | * | |
830 | * This function decodes @fid as long as it has one of the well-known | |
831 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
832 | * inode for the object specified in the file handle. | |
833 | */ | |
834 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
835 | int fh_len, int fh_type, struct inode *(*get_inode) | |
836 | (struct super_block *sb, u64 ino, u32 gen)) | |
837 | { | |
838 | struct inode *inode = NULL; | |
839 | ||
840 | if (fh_len < 2) | |
841 | return NULL; | |
842 | ||
843 | switch (fh_type) { | |
844 | case FILEID_INO32_GEN: | |
845 | case FILEID_INO32_GEN_PARENT: | |
846 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
847 | break; | |
848 | } | |
849 | ||
4ea3ada2 | 850 | return d_obtain_alias(inode); |
2596110a CH |
851 | } |
852 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
853 | ||
854 | /** | |
ca186830 | 855 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a CH |
856 | * @sb: filesystem to do the file handle conversion on |
857 | * @fid: file handle to convert | |
858 | * @fh_len: length of the file handle in bytes | |
859 | * @fh_type: type of file handle | |
860 | * @get_inode: filesystem callback to retrieve inode | |
861 | * | |
862 | * This function decodes @fid as long as it has one of the well-known | |
863 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
864 | * inode for the _parent_ object specified in the file handle if it | |
865 | * is specified in the file handle, or NULL otherwise. | |
866 | */ | |
867 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
868 | int fh_len, int fh_type, struct inode *(*get_inode) | |
869 | (struct super_block *sb, u64 ino, u32 gen)) | |
870 | { | |
871 | struct inode *inode = NULL; | |
872 | ||
873 | if (fh_len <= 2) | |
874 | return NULL; | |
875 | ||
876 | switch (fh_type) { | |
877 | case FILEID_INO32_GEN_PARENT: | |
878 | inode = get_inode(sb, fid->i32.parent_ino, | |
879 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
880 | break; | |
881 | } | |
882 | ||
4ea3ada2 | 883 | return d_obtain_alias(inode); |
2596110a CH |
884 | } |
885 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
886 | ||
1b061d92 CH |
887 | /** |
888 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
889 | * @file: file to synchronize | |
890 | * @datasync: only synchronize essential metadata if true | |
891 | * | |
892 | * This is a generic implementation of the fsync method for simple | |
893 | * filesystems which track all non-inode metadata in the buffers list | |
894 | * hanging off the address_space structure. | |
895 | */ | |
02c24a82 JB |
896 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, |
897 | int datasync) | |
d5aacad5 | 898 | { |
7ea80859 | 899 | struct inode *inode = file->f_mapping->host; |
d5aacad5 AV |
900 | int err; |
901 | int ret; | |
902 | ||
02c24a82 JB |
903 | err = filemap_write_and_wait_range(inode->i_mapping, start, end); |
904 | if (err) | |
905 | return err; | |
906 | ||
907 | mutex_lock(&inode->i_mutex); | |
d5aacad5 AV |
908 | ret = sync_mapping_buffers(inode->i_mapping); |
909 | if (!(inode->i_state & I_DIRTY)) | |
02c24a82 | 910 | goto out; |
d5aacad5 | 911 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a82 | 912 | goto out; |
d5aacad5 | 913 | |
c3765016 | 914 | err = sync_inode_metadata(inode, 1); |
d5aacad5 AV |
915 | if (ret == 0) |
916 | ret = err; | |
02c24a82 JB |
917 | out: |
918 | mutex_unlock(&inode->i_mutex); | |
d5aacad5 AV |
919 | return ret; |
920 | } | |
1b061d92 CH |
921 | EXPORT_SYMBOL(generic_file_fsync); |
922 | ||
30ca22c7 PL |
923 | /** |
924 | * generic_check_addressable - Check addressability of file system | |
925 | * @blocksize_bits: log of file system block size | |
926 | * @num_blocks: number of blocks in file system | |
927 | * | |
928 | * Determine whether a file system with @num_blocks blocks (and a | |
929 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
930 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
931 | */ | |
932 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
933 | { | |
934 | u64 last_fs_block = num_blocks - 1; | |
a33f13ef JB |
935 | u64 last_fs_page = |
936 | last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); | |
30ca22c7 PL |
937 | |
938 | if (unlikely(num_blocks == 0)) | |
939 | return 0; | |
940 | ||
941 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) | |
942 | return -EINVAL; | |
943 | ||
a33f13ef JB |
944 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
945 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
30ca22c7 PL |
946 | return -EFBIG; |
947 | } | |
948 | return 0; | |
949 | } | |
950 | EXPORT_SYMBOL(generic_check_addressable); | |
951 | ||
1b061d92 CH |
952 | /* |
953 | * No-op implementation of ->fsync for in-memory filesystems. | |
954 | */ | |
02c24a82 | 955 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d92 CH |
956 | { |
957 | return 0; | |
958 | } | |
d5aacad5 | 959 | |
1da177e4 LT |
960 | EXPORT_SYMBOL(dcache_dir_close); |
961 | EXPORT_SYMBOL(dcache_dir_lseek); | |
962 | EXPORT_SYMBOL(dcache_dir_open); | |
963 | EXPORT_SYMBOL(dcache_readdir); | |
964 | EXPORT_SYMBOL(generic_read_dir); | |
51139ada | 965 | EXPORT_SYMBOL(mount_pseudo); |
afddba49 NP |
966 | EXPORT_SYMBOL(simple_write_begin); |
967 | EXPORT_SYMBOL(simple_write_end); | |
1da177e4 LT |
968 | EXPORT_SYMBOL(simple_dir_inode_operations); |
969 | EXPORT_SYMBOL(simple_dir_operations); | |
970 | EXPORT_SYMBOL(simple_empty); | |
1da177e4 LT |
971 | EXPORT_SYMBOL(simple_fill_super); |
972 | EXPORT_SYMBOL(simple_getattr); | |
20955e89 | 973 | EXPORT_SYMBOL(simple_open); |
1da177e4 LT |
974 | EXPORT_SYMBOL(simple_link); |
975 | EXPORT_SYMBOL(simple_lookup); | |
976 | EXPORT_SYMBOL(simple_pin_fs); | |
1da177e4 LT |
977 | EXPORT_SYMBOL(simple_readpage); |
978 | EXPORT_SYMBOL(simple_release_fs); | |
979 | EXPORT_SYMBOL(simple_rename); | |
980 | EXPORT_SYMBOL(simple_rmdir); | |
981 | EXPORT_SYMBOL(simple_statfs); | |
1b061d92 | 982 | EXPORT_SYMBOL(noop_fsync); |
1da177e4 LT |
983 | EXPORT_SYMBOL(simple_unlink); |
984 | EXPORT_SYMBOL(simple_read_from_buffer); | |
6a727b43 | 985 | EXPORT_SYMBOL(simple_write_to_buffer); |
93b07113 | 986 | EXPORT_SYMBOL(memory_read_from_buffer); |
76791ab2 | 987 | EXPORT_SYMBOL(simple_transaction_set); |
1da177e4 LT |
988 | EXPORT_SYMBOL(simple_transaction_get); |
989 | EXPORT_SYMBOL(simple_transaction_read); | |
990 | EXPORT_SYMBOL(simple_transaction_release); | |
acaefc25 | 991 | EXPORT_SYMBOL_GPL(simple_attr_open); |
74bedc4d | 992 | EXPORT_SYMBOL_GPL(simple_attr_release); |
acaefc25 AB |
993 | EXPORT_SYMBOL_GPL(simple_attr_read); |
994 | EXPORT_SYMBOL_GPL(simple_attr_write); |