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1 | /* | |
2 | * fs/libfs.c | |
3 | * Library for filesystems writers. | |
4 | */ | |
5 | ||
6 | #include <linux/blkdev.h> | |
7 | #include <linux/export.h> | |
8 | #include <linux/pagemap.h> | |
9 | #include <linux/slab.h> | |
10 | #include <linux/mount.h> | |
11 | #include <linux/vfs.h> | |
12 | #include <linux/quotaops.h> | |
13 | #include <linux/mutex.h> | |
14 | #include <linux/namei.h> | |
15 | #include <linux/exportfs.h> | |
16 | #include <linux/writeback.h> | |
17 | #include <linux/buffer_head.h> /* sync_mapping_buffers */ | |
18 | ||
19 | #include <asm/uaccess.h> | |
20 | ||
21 | #include "internal.h" | |
22 | ||
23 | int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
24 | struct kstat *stat) | |
25 | { | |
26 | struct inode *inode = d_inode(dentry); | |
27 | generic_fillattr(inode, stat); | |
28 | stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); | |
29 | return 0; | |
30 | } | |
31 | EXPORT_SYMBOL(simple_getattr); | |
32 | ||
33 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) | |
34 | { | |
35 | buf->f_type = dentry->d_sb->s_magic; | |
36 | buf->f_bsize = PAGE_CACHE_SIZE; | |
37 | buf->f_namelen = NAME_MAX; | |
38 | return 0; | |
39 | } | |
40 | EXPORT_SYMBOL(simple_statfs); | |
41 | ||
42 | /* | |
43 | * Retaining negative dentries for an in-memory filesystem just wastes | |
44 | * memory and lookup time: arrange for them to be deleted immediately. | |
45 | */ | |
46 | int always_delete_dentry(const struct dentry *dentry) | |
47 | { | |
48 | return 1; | |
49 | } | |
50 | EXPORT_SYMBOL(always_delete_dentry); | |
51 | ||
52 | const struct dentry_operations simple_dentry_operations = { | |
53 | .d_delete = always_delete_dentry, | |
54 | }; | |
55 | EXPORT_SYMBOL(simple_dentry_operations); | |
56 | ||
57 | /* | |
58 | * Lookup the data. This is trivial - if the dentry didn't already | |
59 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
60 | */ | |
61 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
62 | { | |
63 | if (dentry->d_name.len > NAME_MAX) | |
64 | return ERR_PTR(-ENAMETOOLONG); | |
65 | if (!dentry->d_sb->s_d_op) | |
66 | d_set_d_op(dentry, &simple_dentry_operations); | |
67 | d_add(dentry, NULL); | |
68 | return NULL; | |
69 | } | |
70 | EXPORT_SYMBOL(simple_lookup); | |
71 | ||
72 | int dcache_dir_open(struct inode *inode, struct file *file) | |
73 | { | |
74 | static struct qstr cursor_name = QSTR_INIT(".", 1); | |
75 | ||
76 | file->private_data = d_alloc(file->f_path.dentry, &cursor_name); | |
77 | ||
78 | return file->private_data ? 0 : -ENOMEM; | |
79 | } | |
80 | EXPORT_SYMBOL(dcache_dir_open); | |
81 | ||
82 | int dcache_dir_close(struct inode *inode, struct file *file) | |
83 | { | |
84 | dput(file->private_data); | |
85 | return 0; | |
86 | } | |
87 | EXPORT_SYMBOL(dcache_dir_close); | |
88 | ||
89 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) | |
90 | { | |
91 | struct dentry *dentry = file->f_path.dentry; | |
92 | mutex_lock(&d_inode(dentry)->i_mutex); | |
93 | switch (whence) { | |
94 | case 1: | |
95 | offset += file->f_pos; | |
96 | case 0: | |
97 | if (offset >= 0) | |
98 | break; | |
99 | default: | |
100 | mutex_unlock(&d_inode(dentry)->i_mutex); | |
101 | return -EINVAL; | |
102 | } | |
103 | if (offset != file->f_pos) { | |
104 | file->f_pos = offset; | |
105 | if (file->f_pos >= 2) { | |
106 | struct list_head *p; | |
107 | struct dentry *cursor = file->private_data; | |
108 | loff_t n = file->f_pos - 2; | |
109 | ||
110 | spin_lock(&dentry->d_lock); | |
111 | /* d_lock not required for cursor */ | |
112 | list_del(&cursor->d_child); | |
113 | p = dentry->d_subdirs.next; | |
114 | while (n && p != &dentry->d_subdirs) { | |
115 | struct dentry *next; | |
116 | next = list_entry(p, struct dentry, d_child); | |
117 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); | |
118 | if (simple_positive(next)) | |
119 | n--; | |
120 | spin_unlock(&next->d_lock); | |
121 | p = p->next; | |
122 | } | |
123 | list_add_tail(&cursor->d_child, p); | |
124 | spin_unlock(&dentry->d_lock); | |
125 | } | |
126 | } | |
127 | mutex_unlock(&d_inode(dentry)->i_mutex); | |
128 | return offset; | |
129 | } | |
130 | EXPORT_SYMBOL(dcache_dir_lseek); | |
131 | ||
132 | /* Relationship between i_mode and the DT_xxx types */ | |
133 | static inline unsigned char dt_type(struct inode *inode) | |
134 | { | |
135 | return (inode->i_mode >> 12) & 15; | |
136 | } | |
137 | ||
138 | /* | |
139 | * Directory is locked and all positive dentries in it are safe, since | |
140 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
141 | * both impossible due to the lock on directory. | |
142 | */ | |
143 | ||
144 | int dcache_readdir(struct file *file, struct dir_context *ctx) | |
145 | { | |
146 | struct dentry *dentry = file->f_path.dentry; | |
147 | struct dentry *cursor = file->private_data; | |
148 | struct list_head *p, *q = &cursor->d_child; | |
149 | ||
150 | if (!dir_emit_dots(file, ctx)) | |
151 | return 0; | |
152 | spin_lock(&dentry->d_lock); | |
153 | if (ctx->pos == 2) | |
154 | list_move(q, &dentry->d_subdirs); | |
155 | ||
156 | for (p = q->next; p != &dentry->d_subdirs; p = p->next) { | |
157 | struct dentry *next = list_entry(p, struct dentry, d_child); | |
158 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); | |
159 | if (!simple_positive(next)) { | |
160 | spin_unlock(&next->d_lock); | |
161 | continue; | |
162 | } | |
163 | ||
164 | spin_unlock(&next->d_lock); | |
165 | spin_unlock(&dentry->d_lock); | |
166 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, | |
167 | d_inode(next)->i_ino, dt_type(d_inode(next)))) | |
168 | return 0; | |
169 | spin_lock(&dentry->d_lock); | |
170 | spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); | |
171 | /* next is still alive */ | |
172 | list_move(q, p); | |
173 | spin_unlock(&next->d_lock); | |
174 | p = q; | |
175 | ctx->pos++; | |
176 | } | |
177 | spin_unlock(&dentry->d_lock); | |
178 | return 0; | |
179 | } | |
180 | EXPORT_SYMBOL(dcache_readdir); | |
181 | ||
182 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
183 | { | |
184 | return -EISDIR; | |
185 | } | |
186 | EXPORT_SYMBOL(generic_read_dir); | |
187 | ||
188 | const struct file_operations simple_dir_operations = { | |
189 | .open = dcache_dir_open, | |
190 | .release = dcache_dir_close, | |
191 | .llseek = dcache_dir_lseek, | |
192 | .read = generic_read_dir, | |
193 | .iterate = dcache_readdir, | |
194 | .fsync = noop_fsync, | |
195 | }; | |
196 | EXPORT_SYMBOL(simple_dir_operations); | |
197 | ||
198 | const struct inode_operations simple_dir_inode_operations = { | |
199 | .lookup = simple_lookup, | |
200 | }; | |
201 | EXPORT_SYMBOL(simple_dir_inode_operations); | |
202 | ||
203 | static const struct super_operations simple_super_operations = { | |
204 | .statfs = simple_statfs, | |
205 | }; | |
206 | ||
207 | /* | |
208 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
209 | * will never be mountable) | |
210 | */ | |
211 | struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, | |
212 | const struct super_operations *ops, | |
213 | const struct dentry_operations *dops, unsigned long magic) | |
214 | { | |
215 | struct super_block *s; | |
216 | struct dentry *dentry; | |
217 | struct inode *root; | |
218 | struct qstr d_name = QSTR_INIT(name, strlen(name)); | |
219 | ||
220 | s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); | |
221 | if (IS_ERR(s)) | |
222 | return ERR_CAST(s); | |
223 | ||
224 | s->s_maxbytes = MAX_LFS_FILESIZE; | |
225 | s->s_blocksize = PAGE_SIZE; | |
226 | s->s_blocksize_bits = PAGE_SHIFT; | |
227 | s->s_magic = magic; | |
228 | s->s_op = ops ? ops : &simple_super_operations; | |
229 | s->s_time_gran = 1; | |
230 | root = new_inode(s); | |
231 | if (!root) | |
232 | goto Enomem; | |
233 | /* | |
234 | * since this is the first inode, make it number 1. New inodes created | |
235 | * after this must take care not to collide with it (by passing | |
236 | * max_reserved of 1 to iunique). | |
237 | */ | |
238 | root->i_ino = 1; | |
239 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; | |
240 | root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; | |
241 | dentry = __d_alloc(s, &d_name); | |
242 | if (!dentry) { | |
243 | iput(root); | |
244 | goto Enomem; | |
245 | } | |
246 | d_instantiate(dentry, root); | |
247 | s->s_root = dentry; | |
248 | s->s_d_op = dops; | |
249 | s->s_flags |= MS_ACTIVE; | |
250 | return dget(s->s_root); | |
251 | ||
252 | Enomem: | |
253 | deactivate_locked_super(s); | |
254 | return ERR_PTR(-ENOMEM); | |
255 | } | |
256 | EXPORT_SYMBOL(mount_pseudo); | |
257 | ||
258 | int simple_open(struct inode *inode, struct file *file) | |
259 | { | |
260 | if (inode->i_private) | |
261 | file->private_data = inode->i_private; | |
262 | return 0; | |
263 | } | |
264 | EXPORT_SYMBOL(simple_open); | |
265 | ||
266 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
267 | { | |
268 | struct inode *inode = d_inode(old_dentry); | |
269 | ||
270 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
271 | inc_nlink(inode); | |
272 | ihold(inode); | |
273 | dget(dentry); | |
274 | d_instantiate(dentry, inode); | |
275 | return 0; | |
276 | } | |
277 | EXPORT_SYMBOL(simple_link); | |
278 | ||
279 | int simple_empty(struct dentry *dentry) | |
280 | { | |
281 | struct dentry *child; | |
282 | int ret = 0; | |
283 | ||
284 | spin_lock(&dentry->d_lock); | |
285 | list_for_each_entry(child, &dentry->d_subdirs, d_child) { | |
286 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); | |
287 | if (simple_positive(child)) { | |
288 | spin_unlock(&child->d_lock); | |
289 | goto out; | |
290 | } | |
291 | spin_unlock(&child->d_lock); | |
292 | } | |
293 | ret = 1; | |
294 | out: | |
295 | spin_unlock(&dentry->d_lock); | |
296 | return ret; | |
297 | } | |
298 | EXPORT_SYMBOL(simple_empty); | |
299 | ||
300 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
301 | { | |
302 | struct inode *inode = d_inode(dentry); | |
303 | ||
304 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
305 | drop_nlink(inode); | |
306 | dput(dentry); | |
307 | return 0; | |
308 | } | |
309 | EXPORT_SYMBOL(simple_unlink); | |
310 | ||
311 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
312 | { | |
313 | if (!simple_empty(dentry)) | |
314 | return -ENOTEMPTY; | |
315 | ||
316 | drop_nlink(d_inode(dentry)); | |
317 | simple_unlink(dir, dentry); | |
318 | drop_nlink(dir); | |
319 | return 0; | |
320 | } | |
321 | EXPORT_SYMBOL(simple_rmdir); | |
322 | ||
323 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, | |
324 | struct inode *new_dir, struct dentry *new_dentry) | |
325 | { | |
326 | struct inode *inode = d_inode(old_dentry); | |
327 | int they_are_dirs = d_is_dir(old_dentry); | |
328 | ||
329 | if (!simple_empty(new_dentry)) | |
330 | return -ENOTEMPTY; | |
331 | ||
332 | if (d_really_is_positive(new_dentry)) { | |
333 | simple_unlink(new_dir, new_dentry); | |
334 | if (they_are_dirs) { | |
335 | drop_nlink(d_inode(new_dentry)); | |
336 | drop_nlink(old_dir); | |
337 | } | |
338 | } else if (they_are_dirs) { | |
339 | drop_nlink(old_dir); | |
340 | inc_nlink(new_dir); | |
341 | } | |
342 | ||
343 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = | |
344 | new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; | |
345 | ||
346 | return 0; | |
347 | } | |
348 | EXPORT_SYMBOL(simple_rename); | |
349 | ||
350 | /** | |
351 | * simple_setattr - setattr for simple filesystem | |
352 | * @dentry: dentry | |
353 | * @iattr: iattr structure | |
354 | * | |
355 | * Returns 0 on success, -error on failure. | |
356 | * | |
357 | * simple_setattr is a simple ->setattr implementation without a proper | |
358 | * implementation of size changes. | |
359 | * | |
360 | * It can either be used for in-memory filesystems or special files | |
361 | * on simple regular filesystems. Anything that needs to change on-disk | |
362 | * or wire state on size changes needs its own setattr method. | |
363 | */ | |
364 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) | |
365 | { | |
366 | struct inode *inode = d_inode(dentry); | |
367 | int error; | |
368 | ||
369 | error = inode_change_ok(inode, iattr); | |
370 | if (error) | |
371 | return error; | |
372 | ||
373 | if (iattr->ia_valid & ATTR_SIZE) | |
374 | truncate_setsize(inode, iattr->ia_size); | |
375 | setattr_copy(inode, iattr); | |
376 | mark_inode_dirty(inode); | |
377 | return 0; | |
378 | } | |
379 | EXPORT_SYMBOL(simple_setattr); | |
380 | ||
381 | int simple_readpage(struct file *file, struct page *page) | |
382 | { | |
383 | clear_highpage(page); | |
384 | flush_dcache_page(page); | |
385 | SetPageUptodate(page); | |
386 | unlock_page(page); | |
387 | return 0; | |
388 | } | |
389 | EXPORT_SYMBOL(simple_readpage); | |
390 | ||
391 | int simple_write_begin(struct file *file, struct address_space *mapping, | |
392 | loff_t pos, unsigned len, unsigned flags, | |
393 | struct page **pagep, void **fsdata) | |
394 | { | |
395 | struct page *page; | |
396 | pgoff_t index; | |
397 | ||
398 | index = pos >> PAGE_CACHE_SHIFT; | |
399 | ||
400 | page = grab_cache_page_write_begin(mapping, index, flags); | |
401 | if (!page) | |
402 | return -ENOMEM; | |
403 | ||
404 | *pagep = page; | |
405 | ||
406 | if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { | |
407 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
408 | ||
409 | zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); | |
410 | } | |
411 | return 0; | |
412 | } | |
413 | EXPORT_SYMBOL(simple_write_begin); | |
414 | ||
415 | /** | |
416 | * simple_write_end - .write_end helper for non-block-device FSes | |
417 | * @available: See .write_end of address_space_operations | |
418 | * @file: " | |
419 | * @mapping: " | |
420 | * @pos: " | |
421 | * @len: " | |
422 | * @copied: " | |
423 | * @page: " | |
424 | * @fsdata: " | |
425 | * | |
426 | * simple_write_end does the minimum needed for updating a page after writing is | |
427 | * done. It has the same API signature as the .write_end of | |
428 | * address_space_operations vector. So it can just be set onto .write_end for | |
429 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
430 | * Block based filesystems should use generic_write_end(). | |
431 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
432 | * is not called, so a filesystem that actually does store data in .write_inode | |
433 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
434 | * case that i_size has changed. | |
435 | */ | |
436 | int simple_write_end(struct file *file, struct address_space *mapping, | |
437 | loff_t pos, unsigned len, unsigned copied, | |
438 | struct page *page, void *fsdata) | |
439 | { | |
440 | struct inode *inode = page->mapping->host; | |
441 | loff_t last_pos = pos + copied; | |
442 | ||
443 | /* zero the stale part of the page if we did a short copy */ | |
444 | if (copied < len) { | |
445 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
446 | ||
447 | zero_user(page, from + copied, len - copied); | |
448 | } | |
449 | ||
450 | if (!PageUptodate(page)) | |
451 | SetPageUptodate(page); | |
452 | /* | |
453 | * No need to use i_size_read() here, the i_size | |
454 | * cannot change under us because we hold the i_mutex. | |
455 | */ | |
456 | if (last_pos > inode->i_size) | |
457 | i_size_write(inode, last_pos); | |
458 | ||
459 | set_page_dirty(page); | |
460 | unlock_page(page); | |
461 | page_cache_release(page); | |
462 | ||
463 | return copied; | |
464 | } | |
465 | EXPORT_SYMBOL(simple_write_end); | |
466 | ||
467 | /* | |
468 | * the inodes created here are not hashed. If you use iunique to generate | |
469 | * unique inode values later for this filesystem, then you must take care | |
470 | * to pass it an appropriate max_reserved value to avoid collisions. | |
471 | */ | |
472 | int simple_fill_super(struct super_block *s, unsigned long magic, | |
473 | struct tree_descr *files) | |
474 | { | |
475 | struct inode *inode; | |
476 | struct dentry *root; | |
477 | struct dentry *dentry; | |
478 | int i; | |
479 | ||
480 | s->s_blocksize = PAGE_CACHE_SIZE; | |
481 | s->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
482 | s->s_magic = magic; | |
483 | s->s_op = &simple_super_operations; | |
484 | s->s_time_gran = 1; | |
485 | ||
486 | inode = new_inode(s); | |
487 | if (!inode) | |
488 | return -ENOMEM; | |
489 | /* | |
490 | * because the root inode is 1, the files array must not contain an | |
491 | * entry at index 1 | |
492 | */ | |
493 | inode->i_ino = 1; | |
494 | inode->i_mode = S_IFDIR | 0755; | |
495 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
496 | inode->i_op = &simple_dir_inode_operations; | |
497 | inode->i_fop = &simple_dir_operations; | |
498 | set_nlink(inode, 2); | |
499 | root = d_make_root(inode); | |
500 | if (!root) | |
501 | return -ENOMEM; | |
502 | for (i = 0; !files->name || files->name[0]; i++, files++) { | |
503 | if (!files->name) | |
504 | continue; | |
505 | ||
506 | /* warn if it tries to conflict with the root inode */ | |
507 | if (unlikely(i == 1)) | |
508 | printk(KERN_WARNING "%s: %s passed in a files array" | |
509 | "with an index of 1!\n", __func__, | |
510 | s->s_type->name); | |
511 | ||
512 | dentry = d_alloc_name(root, files->name); | |
513 | if (!dentry) | |
514 | goto out; | |
515 | inode = new_inode(s); | |
516 | if (!inode) { | |
517 | dput(dentry); | |
518 | goto out; | |
519 | } | |
520 | inode->i_mode = S_IFREG | files->mode; | |
521 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
522 | inode->i_fop = files->ops; | |
523 | inode->i_ino = i; | |
524 | d_add(dentry, inode); | |
525 | } | |
526 | s->s_root = root; | |
527 | return 0; | |
528 | out: | |
529 | d_genocide(root); | |
530 | shrink_dcache_parent(root); | |
531 | dput(root); | |
532 | return -ENOMEM; | |
533 | } | |
534 | EXPORT_SYMBOL(simple_fill_super); | |
535 | ||
536 | static DEFINE_SPINLOCK(pin_fs_lock); | |
537 | ||
538 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) | |
539 | { | |
540 | struct vfsmount *mnt = NULL; | |
541 | spin_lock(&pin_fs_lock); | |
542 | if (unlikely(!*mount)) { | |
543 | spin_unlock(&pin_fs_lock); | |
544 | mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); | |
545 | if (IS_ERR(mnt)) | |
546 | return PTR_ERR(mnt); | |
547 | spin_lock(&pin_fs_lock); | |
548 | if (!*mount) | |
549 | *mount = mnt; | |
550 | } | |
551 | mntget(*mount); | |
552 | ++*count; | |
553 | spin_unlock(&pin_fs_lock); | |
554 | mntput(mnt); | |
555 | return 0; | |
556 | } | |
557 | EXPORT_SYMBOL(simple_pin_fs); | |
558 | ||
559 | void simple_release_fs(struct vfsmount **mount, int *count) | |
560 | { | |
561 | struct vfsmount *mnt; | |
562 | spin_lock(&pin_fs_lock); | |
563 | mnt = *mount; | |
564 | if (!--*count) | |
565 | *mount = NULL; | |
566 | spin_unlock(&pin_fs_lock); | |
567 | mntput(mnt); | |
568 | } | |
569 | EXPORT_SYMBOL(simple_release_fs); | |
570 | ||
571 | /** | |
572 | * simple_read_from_buffer - copy data from the buffer to user space | |
573 | * @to: the user space buffer to read to | |
574 | * @count: the maximum number of bytes to read | |
575 | * @ppos: the current position in the buffer | |
576 | * @from: the buffer to read from | |
577 | * @available: the size of the buffer | |
578 | * | |
579 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
580 | * buffer @from at offset @ppos into the user space address starting at @to. | |
581 | * | |
582 | * On success, the number of bytes read is returned and the offset @ppos is | |
583 | * advanced by this number, or negative value is returned on error. | |
584 | **/ | |
585 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, | |
586 | const void *from, size_t available) | |
587 | { | |
588 | loff_t pos = *ppos; | |
589 | size_t ret; | |
590 | ||
591 | if (pos < 0) | |
592 | return -EINVAL; | |
593 | if (pos >= available || !count) | |
594 | return 0; | |
595 | if (count > available - pos) | |
596 | count = available - pos; | |
597 | ret = copy_to_user(to, from + pos, count); | |
598 | if (ret == count) | |
599 | return -EFAULT; | |
600 | count -= ret; | |
601 | *ppos = pos + count; | |
602 | return count; | |
603 | } | |
604 | EXPORT_SYMBOL(simple_read_from_buffer); | |
605 | ||
606 | /** | |
607 | * simple_write_to_buffer - copy data from user space to the buffer | |
608 | * @to: the buffer to write to | |
609 | * @available: the size of the buffer | |
610 | * @ppos: the current position in the buffer | |
611 | * @from: the user space buffer to read from | |
612 | * @count: the maximum number of bytes to read | |
613 | * | |
614 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
615 | * space address starting at @from into the buffer @to at offset @ppos. | |
616 | * | |
617 | * On success, the number of bytes written is returned and the offset @ppos is | |
618 | * advanced by this number, or negative value is returned on error. | |
619 | **/ | |
620 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
621 | const void __user *from, size_t count) | |
622 | { | |
623 | loff_t pos = *ppos; | |
624 | size_t res; | |
625 | ||
626 | if (pos < 0) | |
627 | return -EINVAL; | |
628 | if (pos >= available || !count) | |
629 | return 0; | |
630 | if (count > available - pos) | |
631 | count = available - pos; | |
632 | res = copy_from_user(to + pos, from, count); | |
633 | if (res == count) | |
634 | return -EFAULT; | |
635 | count -= res; | |
636 | *ppos = pos + count; | |
637 | return count; | |
638 | } | |
639 | EXPORT_SYMBOL(simple_write_to_buffer); | |
640 | ||
641 | /** | |
642 | * memory_read_from_buffer - copy data from the buffer | |
643 | * @to: the kernel space buffer to read to | |
644 | * @count: the maximum number of bytes to read | |
645 | * @ppos: the current position in the buffer | |
646 | * @from: the buffer to read from | |
647 | * @available: the size of the buffer | |
648 | * | |
649 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
650 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
651 | * | |
652 | * On success, the number of bytes read is returned and the offset @ppos is | |
653 | * advanced by this number, or negative value is returned on error. | |
654 | **/ | |
655 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, | |
656 | const void *from, size_t available) | |
657 | { | |
658 | loff_t pos = *ppos; | |
659 | ||
660 | if (pos < 0) | |
661 | return -EINVAL; | |
662 | if (pos >= available) | |
663 | return 0; | |
664 | if (count > available - pos) | |
665 | count = available - pos; | |
666 | memcpy(to, from + pos, count); | |
667 | *ppos = pos + count; | |
668 | ||
669 | return count; | |
670 | } | |
671 | EXPORT_SYMBOL(memory_read_from_buffer); | |
672 | ||
673 | /* | |
674 | * Transaction based IO. | |
675 | * The file expects a single write which triggers the transaction, and then | |
676 | * possibly a read which collects the result - which is stored in a | |
677 | * file-local buffer. | |
678 | */ | |
679 | ||
680 | void simple_transaction_set(struct file *file, size_t n) | |
681 | { | |
682 | struct simple_transaction_argresp *ar = file->private_data; | |
683 | ||
684 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
685 | ||
686 | /* | |
687 | * The barrier ensures that ar->size will really remain zero until | |
688 | * ar->data is ready for reading. | |
689 | */ | |
690 | smp_mb(); | |
691 | ar->size = n; | |
692 | } | |
693 | EXPORT_SYMBOL(simple_transaction_set); | |
694 | ||
695 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) | |
696 | { | |
697 | struct simple_transaction_argresp *ar; | |
698 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
699 | ||
700 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
701 | return ERR_PTR(-EFBIG); | |
702 | ||
703 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
704 | if (!ar) | |
705 | return ERR_PTR(-ENOMEM); | |
706 | ||
707 | spin_lock(&simple_transaction_lock); | |
708 | ||
709 | /* only one write allowed per open */ | |
710 | if (file->private_data) { | |
711 | spin_unlock(&simple_transaction_lock); | |
712 | free_page((unsigned long)ar); | |
713 | return ERR_PTR(-EBUSY); | |
714 | } | |
715 | ||
716 | file->private_data = ar; | |
717 | ||
718 | spin_unlock(&simple_transaction_lock); | |
719 | ||
720 | if (copy_from_user(ar->data, buf, size)) | |
721 | return ERR_PTR(-EFAULT); | |
722 | ||
723 | return ar->data; | |
724 | } | |
725 | EXPORT_SYMBOL(simple_transaction_get); | |
726 | ||
727 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
728 | { | |
729 | struct simple_transaction_argresp *ar = file->private_data; | |
730 | ||
731 | if (!ar) | |
732 | return 0; | |
733 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
734 | } | |
735 | EXPORT_SYMBOL(simple_transaction_read); | |
736 | ||
737 | int simple_transaction_release(struct inode *inode, struct file *file) | |
738 | { | |
739 | free_page((unsigned long)file->private_data); | |
740 | return 0; | |
741 | } | |
742 | EXPORT_SYMBOL(simple_transaction_release); | |
743 | ||
744 | /* Simple attribute files */ | |
745 | ||
746 | struct simple_attr { | |
747 | int (*get)(void *, u64 *); | |
748 | int (*set)(void *, u64); | |
749 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ | |
750 | char set_buf[24]; | |
751 | void *data; | |
752 | const char *fmt; /* format for read operation */ | |
753 | struct mutex mutex; /* protects access to these buffers */ | |
754 | }; | |
755 | ||
756 | /* simple_attr_open is called by an actual attribute open file operation | |
757 | * to set the attribute specific access operations. */ | |
758 | int simple_attr_open(struct inode *inode, struct file *file, | |
759 | int (*get)(void *, u64 *), int (*set)(void *, u64), | |
760 | const char *fmt) | |
761 | { | |
762 | struct simple_attr *attr; | |
763 | ||
764 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); | |
765 | if (!attr) | |
766 | return -ENOMEM; | |
767 | ||
768 | attr->get = get; | |
769 | attr->set = set; | |
770 | attr->data = inode->i_private; | |
771 | attr->fmt = fmt; | |
772 | mutex_init(&attr->mutex); | |
773 | ||
774 | file->private_data = attr; | |
775 | ||
776 | return nonseekable_open(inode, file); | |
777 | } | |
778 | EXPORT_SYMBOL_GPL(simple_attr_open); | |
779 | ||
780 | int simple_attr_release(struct inode *inode, struct file *file) | |
781 | { | |
782 | kfree(file->private_data); | |
783 | return 0; | |
784 | } | |
785 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ | |
786 | ||
787 | /* read from the buffer that is filled with the get function */ | |
788 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
789 | size_t len, loff_t *ppos) | |
790 | { | |
791 | struct simple_attr *attr; | |
792 | size_t size; | |
793 | ssize_t ret; | |
794 | ||
795 | attr = file->private_data; | |
796 | ||
797 | if (!attr->get) | |
798 | return -EACCES; | |
799 | ||
800 | ret = mutex_lock_interruptible(&attr->mutex); | |
801 | if (ret) | |
802 | return ret; | |
803 | ||
804 | if (*ppos) { /* continued read */ | |
805 | size = strlen(attr->get_buf); | |
806 | } else { /* first read */ | |
807 | u64 val; | |
808 | ret = attr->get(attr->data, &val); | |
809 | if (ret) | |
810 | goto out; | |
811 | ||
812 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), | |
813 | attr->fmt, (unsigned long long)val); | |
814 | } | |
815 | ||
816 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
817 | out: | |
818 | mutex_unlock(&attr->mutex); | |
819 | return ret; | |
820 | } | |
821 | EXPORT_SYMBOL_GPL(simple_attr_read); | |
822 | ||
823 | /* interpret the buffer as a number to call the set function with */ | |
824 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
825 | size_t len, loff_t *ppos) | |
826 | { | |
827 | struct simple_attr *attr; | |
828 | u64 val; | |
829 | size_t size; | |
830 | ssize_t ret; | |
831 | ||
832 | attr = file->private_data; | |
833 | if (!attr->set) | |
834 | return -EACCES; | |
835 | ||
836 | ret = mutex_lock_interruptible(&attr->mutex); | |
837 | if (ret) | |
838 | return ret; | |
839 | ||
840 | ret = -EFAULT; | |
841 | size = min(sizeof(attr->set_buf) - 1, len); | |
842 | if (copy_from_user(attr->set_buf, buf, size)) | |
843 | goto out; | |
844 | ||
845 | attr->set_buf[size] = '\0'; | |
846 | val = simple_strtoll(attr->set_buf, NULL, 0); | |
847 | ret = attr->set(attr->data, val); | |
848 | if (ret == 0) | |
849 | ret = len; /* on success, claim we got the whole input */ | |
850 | out: | |
851 | mutex_unlock(&attr->mutex); | |
852 | return ret; | |
853 | } | |
854 | EXPORT_SYMBOL_GPL(simple_attr_write); | |
855 | ||
856 | /** | |
857 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
858 | * @sb: filesystem to do the file handle conversion on | |
859 | * @fid: file handle to convert | |
860 | * @fh_len: length of the file handle in bytes | |
861 | * @fh_type: type of file handle | |
862 | * @get_inode: filesystem callback to retrieve inode | |
863 | * | |
864 | * This function decodes @fid as long as it has one of the well-known | |
865 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
866 | * inode for the object specified in the file handle. | |
867 | */ | |
868 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
869 | int fh_len, int fh_type, struct inode *(*get_inode) | |
870 | (struct super_block *sb, u64 ino, u32 gen)) | |
871 | { | |
872 | struct inode *inode = NULL; | |
873 | ||
874 | if (fh_len < 2) | |
875 | return NULL; | |
876 | ||
877 | switch (fh_type) { | |
878 | case FILEID_INO32_GEN: | |
879 | case FILEID_INO32_GEN_PARENT: | |
880 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
881 | break; | |
882 | } | |
883 | ||
884 | return d_obtain_alias(inode); | |
885 | } | |
886 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
887 | ||
888 | /** | |
889 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation | |
890 | * @sb: filesystem to do the file handle conversion on | |
891 | * @fid: file handle to convert | |
892 | * @fh_len: length of the file handle in bytes | |
893 | * @fh_type: type of file handle | |
894 | * @get_inode: filesystem callback to retrieve inode | |
895 | * | |
896 | * This function decodes @fid as long as it has one of the well-known | |
897 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
898 | * inode for the _parent_ object specified in the file handle if it | |
899 | * is specified in the file handle, or NULL otherwise. | |
900 | */ | |
901 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
902 | int fh_len, int fh_type, struct inode *(*get_inode) | |
903 | (struct super_block *sb, u64 ino, u32 gen)) | |
904 | { | |
905 | struct inode *inode = NULL; | |
906 | ||
907 | if (fh_len <= 2) | |
908 | return NULL; | |
909 | ||
910 | switch (fh_type) { | |
911 | case FILEID_INO32_GEN_PARENT: | |
912 | inode = get_inode(sb, fid->i32.parent_ino, | |
913 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
914 | break; | |
915 | } | |
916 | ||
917 | return d_obtain_alias(inode); | |
918 | } | |
919 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
920 | ||
921 | /** | |
922 | * __generic_file_fsync - generic fsync implementation for simple filesystems | |
923 | * | |
924 | * @file: file to synchronize | |
925 | * @start: start offset in bytes | |
926 | * @end: end offset in bytes (inclusive) | |
927 | * @datasync: only synchronize essential metadata if true | |
928 | * | |
929 | * This is a generic implementation of the fsync method for simple | |
930 | * filesystems which track all non-inode metadata in the buffers list | |
931 | * hanging off the address_space structure. | |
932 | */ | |
933 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, | |
934 | int datasync) | |
935 | { | |
936 | struct inode *inode = file->f_mapping->host; | |
937 | int err; | |
938 | int ret; | |
939 | ||
940 | err = filemap_write_and_wait_range(inode->i_mapping, start, end); | |
941 | if (err) | |
942 | return err; | |
943 | ||
944 | mutex_lock(&inode->i_mutex); | |
945 | ret = sync_mapping_buffers(inode->i_mapping); | |
946 | if (!(inode->i_state & I_DIRTY_ALL)) | |
947 | goto out; | |
948 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) | |
949 | goto out; | |
950 | ||
951 | err = sync_inode_metadata(inode, 1); | |
952 | if (ret == 0) | |
953 | ret = err; | |
954 | ||
955 | out: | |
956 | mutex_unlock(&inode->i_mutex); | |
957 | return ret; | |
958 | } | |
959 | EXPORT_SYMBOL(__generic_file_fsync); | |
960 | ||
961 | /** | |
962 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
963 | * with flush | |
964 | * @file: file to synchronize | |
965 | * @start: start offset in bytes | |
966 | * @end: end offset in bytes (inclusive) | |
967 | * @datasync: only synchronize essential metadata if true | |
968 | * | |
969 | */ | |
970 | ||
971 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, | |
972 | int datasync) | |
973 | { | |
974 | struct inode *inode = file->f_mapping->host; | |
975 | int err; | |
976 | ||
977 | err = __generic_file_fsync(file, start, end, datasync); | |
978 | if (err) | |
979 | return err; | |
980 | return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); | |
981 | } | |
982 | EXPORT_SYMBOL(generic_file_fsync); | |
983 | ||
984 | /** | |
985 | * generic_check_addressable - Check addressability of file system | |
986 | * @blocksize_bits: log of file system block size | |
987 | * @num_blocks: number of blocks in file system | |
988 | * | |
989 | * Determine whether a file system with @num_blocks blocks (and a | |
990 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
991 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
992 | */ | |
993 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
994 | { | |
995 | u64 last_fs_block = num_blocks - 1; | |
996 | u64 last_fs_page = | |
997 | last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); | |
998 | ||
999 | if (unlikely(num_blocks == 0)) | |
1000 | return 0; | |
1001 | ||
1002 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) | |
1003 | return -EINVAL; | |
1004 | ||
1005 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || | |
1006 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
1007 | return -EFBIG; | |
1008 | } | |
1009 | return 0; | |
1010 | } | |
1011 | EXPORT_SYMBOL(generic_check_addressable); | |
1012 | ||
1013 | /* | |
1014 | * No-op implementation of ->fsync for in-memory filesystems. | |
1015 | */ | |
1016 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) | |
1017 | { | |
1018 | return 0; | |
1019 | } | |
1020 | EXPORT_SYMBOL(noop_fsync); | |
1021 | ||
1022 | void kfree_put_link(struct inode *unused, void *cookie) | |
1023 | { | |
1024 | kfree(cookie); | |
1025 | } | |
1026 | EXPORT_SYMBOL(kfree_put_link); | |
1027 | ||
1028 | void free_page_put_link(struct inode *unused, void *cookie) | |
1029 | { | |
1030 | free_page((unsigned long) cookie); | |
1031 | } | |
1032 | EXPORT_SYMBOL(free_page_put_link); | |
1033 | ||
1034 | /* | |
1035 | * nop .set_page_dirty method so that people can use .page_mkwrite on | |
1036 | * anon inodes. | |
1037 | */ | |
1038 | static int anon_set_page_dirty(struct page *page) | |
1039 | { | |
1040 | return 0; | |
1041 | }; | |
1042 | ||
1043 | /* | |
1044 | * A single inode exists for all anon_inode files. Contrary to pipes, | |
1045 | * anon_inode inodes have no associated per-instance data, so we need | |
1046 | * only allocate one of them. | |
1047 | */ | |
1048 | struct inode *alloc_anon_inode(struct super_block *s) | |
1049 | { | |
1050 | static const struct address_space_operations anon_aops = { | |
1051 | .set_page_dirty = anon_set_page_dirty, | |
1052 | }; | |
1053 | struct inode *inode = new_inode_pseudo(s); | |
1054 | ||
1055 | if (!inode) | |
1056 | return ERR_PTR(-ENOMEM); | |
1057 | ||
1058 | inode->i_ino = get_next_ino(); | |
1059 | inode->i_mapping->a_ops = &anon_aops; | |
1060 | ||
1061 | /* | |
1062 | * Mark the inode dirty from the very beginning, | |
1063 | * that way it will never be moved to the dirty | |
1064 | * list because mark_inode_dirty() will think | |
1065 | * that it already _is_ on the dirty list. | |
1066 | */ | |
1067 | inode->i_state = I_DIRTY; | |
1068 | inode->i_mode = S_IRUSR | S_IWUSR; | |
1069 | inode->i_uid = current_fsuid(); | |
1070 | inode->i_gid = current_fsgid(); | |
1071 | inode->i_flags |= S_PRIVATE; | |
1072 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
1073 | return inode; | |
1074 | } | |
1075 | EXPORT_SYMBOL(alloc_anon_inode); | |
1076 | ||
1077 | /** | |
1078 | * simple_nosetlease - generic helper for prohibiting leases | |
1079 | * @filp: file pointer | |
1080 | * @arg: type of lease to obtain | |
1081 | * @flp: new lease supplied for insertion | |
1082 | * @priv: private data for lm_setup operation | |
1083 | * | |
1084 | * Generic helper for filesystems that do not wish to allow leases to be set. | |
1085 | * All arguments are ignored and it just returns -EINVAL. | |
1086 | */ | |
1087 | int | |
1088 | simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, | |
1089 | void **priv) | |
1090 | { | |
1091 | return -EINVAL; | |
1092 | } | |
1093 | EXPORT_SYMBOL(simple_nosetlease); | |
1094 | ||
1095 | const char *simple_follow_link(struct dentry *dentry, void **cookie) | |
1096 | { | |
1097 | return d_inode(dentry)->i_link; | |
1098 | } | |
1099 | EXPORT_SYMBOL(simple_follow_link); | |
1100 | ||
1101 | const struct inode_operations simple_symlink_inode_operations = { | |
1102 | .follow_link = simple_follow_link, | |
1103 | .readlink = generic_readlink | |
1104 | }; | |
1105 | EXPORT_SYMBOL(simple_symlink_inode_operations); | |
1106 | ||
1107 | /* | |
1108 | * Operations for a permanently empty directory. | |
1109 | */ | |
1110 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
1111 | { | |
1112 | return ERR_PTR(-ENOENT); | |
1113 | } | |
1114 | ||
1115 | static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
1116 | struct kstat *stat) | |
1117 | { | |
1118 | struct inode *inode = d_inode(dentry); | |
1119 | generic_fillattr(inode, stat); | |
1120 | return 0; | |
1121 | } | |
1122 | ||
1123 | static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) | |
1124 | { | |
1125 | return -EPERM; | |
1126 | } | |
1127 | ||
1128 | static int empty_dir_setxattr(struct dentry *dentry, const char *name, | |
1129 | const void *value, size_t size, int flags) | |
1130 | { | |
1131 | return -EOPNOTSUPP; | |
1132 | } | |
1133 | ||
1134 | static ssize_t empty_dir_getxattr(struct dentry *dentry, const char *name, | |
1135 | void *value, size_t size) | |
1136 | { | |
1137 | return -EOPNOTSUPP; | |
1138 | } | |
1139 | ||
1140 | static int empty_dir_removexattr(struct dentry *dentry, const char *name) | |
1141 | { | |
1142 | return -EOPNOTSUPP; | |
1143 | } | |
1144 | ||
1145 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) | |
1146 | { | |
1147 | return -EOPNOTSUPP; | |
1148 | } | |
1149 | ||
1150 | static const struct inode_operations empty_dir_inode_operations = { | |
1151 | .lookup = empty_dir_lookup, | |
1152 | .permission = generic_permission, | |
1153 | .setattr = empty_dir_setattr, | |
1154 | .getattr = empty_dir_getattr, | |
1155 | .setxattr = empty_dir_setxattr, | |
1156 | .getxattr = empty_dir_getxattr, | |
1157 | .removexattr = empty_dir_removexattr, | |
1158 | .listxattr = empty_dir_listxattr, | |
1159 | }; | |
1160 | ||
1161 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) | |
1162 | { | |
1163 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ | |
1164 | return generic_file_llseek_size(file, offset, whence, 2, 2); | |
1165 | } | |
1166 | ||
1167 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) | |
1168 | { | |
1169 | dir_emit_dots(file, ctx); | |
1170 | return 0; | |
1171 | } | |
1172 | ||
1173 | static const struct file_operations empty_dir_operations = { | |
1174 | .llseek = empty_dir_llseek, | |
1175 | .read = generic_read_dir, | |
1176 | .iterate = empty_dir_readdir, | |
1177 | .fsync = noop_fsync, | |
1178 | }; | |
1179 | ||
1180 | ||
1181 | void make_empty_dir_inode(struct inode *inode) | |
1182 | { | |
1183 | set_nlink(inode, 2); | |
1184 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; | |
1185 | inode->i_uid = GLOBAL_ROOT_UID; | |
1186 | inode->i_gid = GLOBAL_ROOT_GID; | |
1187 | inode->i_rdev = 0; | |
1188 | inode->i_size = 0; | |
1189 | inode->i_blkbits = PAGE_SHIFT; | |
1190 | inode->i_blocks = 0; | |
1191 | ||
1192 | inode->i_op = &empty_dir_inode_operations; | |
1193 | inode->i_fop = &empty_dir_operations; | |
1194 | } | |
1195 | ||
1196 | bool is_empty_dir_inode(struct inode *inode) | |
1197 | { | |
1198 | return (inode->i_fop == &empty_dir_operations) && | |
1199 | (inode->i_op == &empty_dir_inode_operations); | |
1200 | } |