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0eeca283 RL |
1 | /* |
2 | * fs/inotify.c - inode-based file event notifications | |
3 | * | |
4 | * Authors: | |
5 | * John McCutchan <ttb@tentacle.dhs.org> | |
6 | * Robert Love <rml@novell.com> | |
7 | * | |
8 | * Copyright (C) 2005 John McCutchan | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify it | |
11 | * under the terms of the GNU General Public License as published by the | |
12 | * Free Software Foundation; either version 2, or (at your option) any | |
13 | * later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, but | |
16 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | * General Public License for more details. | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/kernel.h> | |
23 | #include <linux/sched.h> | |
24 | #include <linux/spinlock.h> | |
25 | #include <linux/idr.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/fs.h> | |
28 | #include <linux/file.h> | |
29 | #include <linux/mount.h> | |
30 | #include <linux/namei.h> | |
31 | #include <linux/poll.h> | |
0eeca283 RL |
32 | #include <linux/init.h> |
33 | #include <linux/list.h> | |
34 | #include <linux/writeback.h> | |
35 | #include <linux/inotify.h> | |
5131cf15 | 36 | #include <linux/syscalls.h> |
0eeca283 RL |
37 | |
38 | #include <asm/ioctls.h> | |
39 | ||
40 | static atomic_t inotify_cookie; | |
41 | ||
fa3536cc ED |
42 | static kmem_cache_t *watch_cachep __read_mostly; |
43 | static kmem_cache_t *event_cachep __read_mostly; | |
0eeca283 | 44 | |
fa3536cc | 45 | static struct vfsmount *inotify_mnt __read_mostly; |
0eeca283 | 46 | |
0399cb08 | 47 | /* these are configurable via /proc/sys/fs/inotify/ */ |
fa3536cc ED |
48 | int inotify_max_user_instances __read_mostly; |
49 | int inotify_max_user_watches __read_mostly; | |
50 | int inotify_max_queued_events __read_mostly; | |
0eeca283 RL |
51 | |
52 | /* | |
53 | * Lock ordering: | |
54 | * | |
55 | * dentry->d_lock (used to keep d_move() away from dentry->d_parent) | |
f24075bd | 56 | * iprune_mutex (synchronize shrink_icache_memory()) |
0eeca283 | 57 | * inode_lock (protects the super_block->s_inodes list) |
d4f9af9d IM |
58 | * inode->inotify_mutex (protects inode->inotify_watches and watches->i_list) |
59 | * inotify_dev->mutex (protects inotify_device and watches->d_list) | |
0eeca283 RL |
60 | */ |
61 | ||
62 | /* | |
63 | * Lifetimes of the three main data structures--inotify_device, inode, and | |
64 | * inotify_watch--are managed by reference count. | |
65 | * | |
b680716e RL |
66 | * inotify_device: Lifetime is from inotify_init() until release. Additional |
67 | * references can bump the count via get_inotify_dev() and drop the count via | |
0eeca283 RL |
68 | * put_inotify_dev(). |
69 | * | |
70 | * inotify_watch: Lifetime is from create_watch() to destory_watch(). | |
71 | * Additional references can bump the count via get_inotify_watch() and drop | |
72 | * the count via put_inotify_watch(). | |
73 | * | |
74 | * inode: Pinned so long as the inode is associated with a watch, from | |
75 | * create_watch() to put_inotify_watch(). | |
76 | */ | |
77 | ||
78 | /* | |
b680716e | 79 | * struct inotify_device - represents an inotify instance |
0eeca283 | 80 | * |
d4f9af9d | 81 | * This structure is protected by the mutex 'mutex'. |
0eeca283 RL |
82 | */ |
83 | struct inotify_device { | |
84 | wait_queue_head_t wq; /* wait queue for i/o */ | |
85 | struct idr idr; /* idr mapping wd -> watch */ | |
d4f9af9d | 86 | struct mutex mutex; /* protects this bad boy */ |
0eeca283 RL |
87 | struct list_head events; /* list of queued events */ |
88 | struct list_head watches; /* list of watches */ | |
89 | atomic_t count; /* reference count */ | |
90 | struct user_struct *user; /* user who opened this dev */ | |
91 | unsigned int queue_size; /* size of the queue (bytes) */ | |
92 | unsigned int event_count; /* number of pending events */ | |
93 | unsigned int max_events; /* maximum number of events */ | |
b9c55d29 | 94 | u32 last_wd; /* the last wd allocated */ |
0eeca283 RL |
95 | }; |
96 | ||
97 | /* | |
98 | * struct inotify_kernel_event - An inotify event, originating from a watch and | |
99 | * queued for user-space. A list of these is attached to each instance of the | |
100 | * device. In read(), this list is walked and all events that can fit in the | |
101 | * buffer are returned. | |
102 | * | |
d4f9af9d | 103 | * Protected by dev->mutex of the device in which we are queued. |
0eeca283 RL |
104 | */ |
105 | struct inotify_kernel_event { | |
106 | struct inotify_event event; /* the user-space event */ | |
107 | struct list_head list; /* entry in inotify_device's list */ | |
108 | char *name; /* filename, if any */ | |
109 | }; | |
110 | ||
111 | /* | |
112 | * struct inotify_watch - represents a watch request on a specific inode | |
113 | * | |
d4f9af9d IM |
114 | * d_list is protected by dev->mutex of the associated watch->dev. |
115 | * i_list and mask are protected by inode->inotify_mutex of the associated inode. | |
0eeca283 RL |
116 | * dev, inode, and wd are never written to once the watch is created. |
117 | */ | |
118 | struct inotify_watch { | |
119 | struct list_head d_list; /* entry in inotify_device's list */ | |
120 | struct list_head i_list; /* entry in inode's list */ | |
121 | atomic_t count; /* reference count */ | |
122 | struct inotify_device *dev; /* associated device */ | |
123 | struct inode *inode; /* associated inode */ | |
124 | s32 wd; /* watch descriptor */ | |
125 | u32 mask; /* event mask for this watch */ | |
126 | }; | |
127 | ||
0399cb08 RL |
128 | #ifdef CONFIG_SYSCTL |
129 | ||
130 | #include <linux/sysctl.h> | |
131 | ||
132 | static int zero; | |
133 | ||
134 | ctl_table inotify_table[] = { | |
135 | { | |
136 | .ctl_name = INOTIFY_MAX_USER_INSTANCES, | |
137 | .procname = "max_user_instances", | |
138 | .data = &inotify_max_user_instances, | |
139 | .maxlen = sizeof(int), | |
140 | .mode = 0644, | |
141 | .proc_handler = &proc_dointvec_minmax, | |
142 | .strategy = &sysctl_intvec, | |
143 | .extra1 = &zero, | |
144 | }, | |
145 | { | |
146 | .ctl_name = INOTIFY_MAX_USER_WATCHES, | |
147 | .procname = "max_user_watches", | |
148 | .data = &inotify_max_user_watches, | |
149 | .maxlen = sizeof(int), | |
150 | .mode = 0644, | |
151 | .proc_handler = &proc_dointvec_minmax, | |
152 | .strategy = &sysctl_intvec, | |
153 | .extra1 = &zero, | |
154 | }, | |
155 | { | |
156 | .ctl_name = INOTIFY_MAX_QUEUED_EVENTS, | |
157 | .procname = "max_queued_events", | |
158 | .data = &inotify_max_queued_events, | |
159 | .maxlen = sizeof(int), | |
160 | .mode = 0644, | |
161 | .proc_handler = &proc_dointvec_minmax, | |
162 | .strategy = &sysctl_intvec, | |
163 | .extra1 = &zero | |
164 | }, | |
165 | { .ctl_name = 0 } | |
166 | }; | |
167 | #endif /* CONFIG_SYSCTL */ | |
168 | ||
0eeca283 RL |
169 | static inline void get_inotify_dev(struct inotify_device *dev) |
170 | { | |
171 | atomic_inc(&dev->count); | |
172 | } | |
173 | ||
174 | static inline void put_inotify_dev(struct inotify_device *dev) | |
175 | { | |
176 | if (atomic_dec_and_test(&dev->count)) { | |
177 | atomic_dec(&dev->user->inotify_devs); | |
178 | free_uid(dev->user); | |
8d3b3591 | 179 | idr_destroy(&dev->idr); |
0eeca283 RL |
180 | kfree(dev); |
181 | } | |
182 | } | |
183 | ||
184 | static inline void get_inotify_watch(struct inotify_watch *watch) | |
185 | { | |
186 | atomic_inc(&watch->count); | |
187 | } | |
188 | ||
189 | /* | |
190 | * put_inotify_watch - decrements the ref count on a given watch. cleans up | |
191 | * the watch and its references if the count reaches zero. | |
192 | */ | |
193 | static inline void put_inotify_watch(struct inotify_watch *watch) | |
194 | { | |
195 | if (atomic_dec_and_test(&watch->count)) { | |
196 | put_inotify_dev(watch->dev); | |
197 | iput(watch->inode); | |
198 | kmem_cache_free(watch_cachep, watch); | |
199 | } | |
200 | } | |
201 | ||
202 | /* | |
203 | * kernel_event - create a new kernel event with the given parameters | |
204 | * | |
205 | * This function can sleep. | |
206 | */ | |
207 | static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie, | |
208 | const char *name) | |
209 | { | |
210 | struct inotify_kernel_event *kevent; | |
211 | ||
212 | kevent = kmem_cache_alloc(event_cachep, GFP_KERNEL); | |
213 | if (unlikely(!kevent)) | |
214 | return NULL; | |
215 | ||
216 | /* we hand this out to user-space, so zero it just in case */ | |
217 | memset(&kevent->event, 0, sizeof(struct inotify_event)); | |
218 | ||
219 | kevent->event.wd = wd; | |
220 | kevent->event.mask = mask; | |
221 | kevent->event.cookie = cookie; | |
222 | ||
223 | INIT_LIST_HEAD(&kevent->list); | |
224 | ||
225 | if (name) { | |
226 | size_t len, rem, event_size = sizeof(struct inotify_event); | |
227 | ||
228 | /* | |
229 | * We need to pad the filename so as to properly align an | |
230 | * array of inotify_event structures. Because the structure is | |
231 | * small and the common case is a small filename, we just round | |
232 | * up to the next multiple of the structure's sizeof. This is | |
233 | * simple and safe for all architectures. | |
234 | */ | |
235 | len = strlen(name) + 1; | |
236 | rem = event_size - len; | |
237 | if (len > event_size) { | |
238 | rem = event_size - (len % event_size); | |
239 | if (len % event_size == 0) | |
240 | rem = 0; | |
241 | } | |
242 | ||
243 | kevent->name = kmalloc(len + rem, GFP_KERNEL); | |
244 | if (unlikely(!kevent->name)) { | |
245 | kmem_cache_free(event_cachep, kevent); | |
246 | return NULL; | |
247 | } | |
248 | memcpy(kevent->name, name, len); | |
249 | if (rem) | |
250 | memset(kevent->name + len, 0, rem); | |
251 | kevent->event.len = len + rem; | |
252 | } else { | |
253 | kevent->event.len = 0; | |
254 | kevent->name = NULL; | |
255 | } | |
256 | ||
257 | return kevent; | |
258 | } | |
259 | ||
260 | /* | |
261 | * inotify_dev_get_event - return the next event in the given dev's queue | |
262 | * | |
d4f9af9d | 263 | * Caller must hold dev->mutex. |
0eeca283 RL |
264 | */ |
265 | static inline struct inotify_kernel_event * | |
266 | inotify_dev_get_event(struct inotify_device *dev) | |
267 | { | |
268 | return list_entry(dev->events.next, struct inotify_kernel_event, list); | |
269 | } | |
270 | ||
271 | /* | |
272 | * inotify_dev_queue_event - add a new event to the given device | |
273 | * | |
d4f9af9d | 274 | * Caller must hold dev->mutex. Can sleep (calls kernel_event()). |
0eeca283 RL |
275 | */ |
276 | static void inotify_dev_queue_event(struct inotify_device *dev, | |
277 | struct inotify_watch *watch, u32 mask, | |
278 | u32 cookie, const char *name) | |
279 | { | |
280 | struct inotify_kernel_event *kevent, *last; | |
281 | ||
282 | /* coalescing: drop this event if it is a dupe of the previous */ | |
283 | last = inotify_dev_get_event(dev); | |
284 | if (last && last->event.mask == mask && last->event.wd == watch->wd && | |
285 | last->event.cookie == cookie) { | |
286 | const char *lastname = last->name; | |
287 | ||
288 | if (!name && !lastname) | |
289 | return; | |
290 | if (name && lastname && !strcmp(lastname, name)) | |
291 | return; | |
292 | } | |
293 | ||
294 | /* the queue overflowed and we already sent the Q_OVERFLOW event */ | |
295 | if (unlikely(dev->event_count > dev->max_events)) | |
296 | return; | |
297 | ||
298 | /* if the queue overflows, we need to notify user space */ | |
299 | if (unlikely(dev->event_count == dev->max_events)) | |
300 | kevent = kernel_event(-1, IN_Q_OVERFLOW, cookie, NULL); | |
301 | else | |
302 | kevent = kernel_event(watch->wd, mask, cookie, name); | |
303 | ||
304 | if (unlikely(!kevent)) | |
305 | return; | |
306 | ||
307 | /* queue the event and wake up anyone waiting */ | |
308 | dev->event_count++; | |
309 | dev->queue_size += sizeof(struct inotify_event) + kevent->event.len; | |
310 | list_add_tail(&kevent->list, &dev->events); | |
311 | wake_up_interruptible(&dev->wq); | |
312 | } | |
313 | ||
314 | /* | |
315 | * remove_kevent - cleans up and ultimately frees the given kevent | |
316 | * | |
d4f9af9d | 317 | * Caller must hold dev->mutex. |
0eeca283 RL |
318 | */ |
319 | static void remove_kevent(struct inotify_device *dev, | |
320 | struct inotify_kernel_event *kevent) | |
321 | { | |
322 | list_del(&kevent->list); | |
323 | ||
324 | dev->event_count--; | |
325 | dev->queue_size -= sizeof(struct inotify_event) + kevent->event.len; | |
326 | ||
327 | kfree(kevent->name); | |
328 | kmem_cache_free(event_cachep, kevent); | |
329 | } | |
330 | ||
331 | /* | |
332 | * inotify_dev_event_dequeue - destroy an event on the given device | |
333 | * | |
d4f9af9d | 334 | * Caller must hold dev->mutex. |
0eeca283 RL |
335 | */ |
336 | static void inotify_dev_event_dequeue(struct inotify_device *dev) | |
337 | { | |
338 | if (!list_empty(&dev->events)) { | |
339 | struct inotify_kernel_event *kevent; | |
340 | kevent = inotify_dev_get_event(dev); | |
341 | remove_kevent(dev, kevent); | |
342 | } | |
343 | } | |
344 | ||
345 | /* | |
346 | * inotify_dev_get_wd - returns the next WD for use by the given dev | |
347 | * | |
d4f9af9d | 348 | * Callers must hold dev->mutex. This function can sleep. |
0eeca283 RL |
349 | */ |
350 | static int inotify_dev_get_wd(struct inotify_device *dev, | |
351 | struct inotify_watch *watch) | |
352 | { | |
353 | int ret; | |
354 | ||
355 | do { | |
356 | if (unlikely(!idr_pre_get(&dev->idr, GFP_KERNEL))) | |
357 | return -ENOSPC; | |
7c657f2f | 358 | ret = idr_get_new_above(&dev->idr, watch, dev->last_wd+1, &watch->wd); |
0eeca283 RL |
359 | } while (ret == -EAGAIN); |
360 | ||
361 | return ret; | |
362 | } | |
363 | ||
364 | /* | |
365 | * find_inode - resolve a user-given path to a specific inode and return a nd | |
366 | */ | |
8140a500 JM |
367 | static int find_inode(const char __user *dirname, struct nameidata *nd, |
368 | unsigned flags) | |
0eeca283 RL |
369 | { |
370 | int error; | |
371 | ||
8140a500 | 372 | error = __user_walk(dirname, flags, nd); |
0eeca283 RL |
373 | if (error) |
374 | return error; | |
375 | /* you can only watch an inode if you have read permissions on it */ | |
e4543edd | 376 | error = vfs_permission(nd, MAY_READ); |
0eeca283 | 377 | if (error) |
b680716e | 378 | path_release(nd); |
0eeca283 RL |
379 | return error; |
380 | } | |
381 | ||
c32ccd87 NP |
382 | /* |
383 | * inotify_inode_watched - returns nonzero if there are watches on this inode | |
384 | * and zero otherwise. We call this lockless, we do not care if we race. | |
385 | */ | |
386 | static inline int inotify_inode_watched(struct inode *inode) | |
387 | { | |
388 | return !list_empty(&inode->inotify_watches); | |
389 | } | |
390 | ||
391 | /* | |
392 | * Get child dentry flag into synch with parent inode. | |
393 | * Flag should always be clear for negative dentrys. | |
394 | */ | |
395 | static void set_dentry_child_flags(struct inode *inode, int watched) | |
396 | { | |
397 | struct dentry *alias; | |
398 | ||
399 | spin_lock(&dcache_lock); | |
400 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { | |
401 | struct dentry *child; | |
402 | ||
403 | list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) { | |
404 | if (!child->d_inode) { | |
405 | WARN_ON(child->d_flags & DCACHE_INOTIFY_PARENT_WATCHED); | |
406 | continue; | |
407 | } | |
408 | spin_lock(&child->d_lock); | |
409 | if (watched) { | |
410 | WARN_ON(child->d_flags & | |
411 | DCACHE_INOTIFY_PARENT_WATCHED); | |
412 | child->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; | |
413 | } else { | |
414 | WARN_ON(!(child->d_flags & | |
415 | DCACHE_INOTIFY_PARENT_WATCHED)); | |
416 | child->d_flags&=~DCACHE_INOTIFY_PARENT_WATCHED; | |
417 | } | |
418 | spin_unlock(&child->d_lock); | |
419 | } | |
420 | } | |
421 | spin_unlock(&dcache_lock); | |
422 | } | |
423 | ||
0eeca283 RL |
424 | /* |
425 | * create_watch - creates a watch on the given device. | |
426 | * | |
d4f9af9d | 427 | * Callers must hold dev->mutex. Calls inotify_dev_get_wd() so may sleep. |
0eeca283 RL |
428 | * Both 'dev' and 'inode' (by way of nameidata) need to be pinned. |
429 | */ | |
430 | static struct inotify_watch *create_watch(struct inotify_device *dev, | |
431 | u32 mask, struct inode *inode) | |
432 | { | |
433 | struct inotify_watch *watch; | |
434 | int ret; | |
435 | ||
b680716e RL |
436 | if (atomic_read(&dev->user->inotify_watches) >= |
437 | inotify_max_user_watches) | |
0eeca283 RL |
438 | return ERR_PTR(-ENOSPC); |
439 | ||
440 | watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL); | |
441 | if (unlikely(!watch)) | |
442 | return ERR_PTR(-ENOMEM); | |
443 | ||
444 | ret = inotify_dev_get_wd(dev, watch); | |
445 | if (unlikely(ret)) { | |
446 | kmem_cache_free(watch_cachep, watch); | |
447 | return ERR_PTR(ret); | |
448 | } | |
449 | ||
0bf955ce | 450 | dev->last_wd = watch->wd; |
0eeca283 RL |
451 | watch->mask = mask; |
452 | atomic_set(&watch->count, 0); | |
453 | INIT_LIST_HEAD(&watch->d_list); | |
454 | INIT_LIST_HEAD(&watch->i_list); | |
455 | ||
456 | /* save a reference to device and bump the count to make it official */ | |
457 | get_inotify_dev(dev); | |
458 | watch->dev = dev; | |
459 | ||
460 | /* | |
461 | * Save a reference to the inode and bump the ref count to make it | |
462 | * official. We hold a reference to nameidata, which makes this safe. | |
463 | */ | |
464 | watch->inode = igrab(inode); | |
465 | ||
466 | /* bump our own count, corresponding to our entry in dev->watches */ | |
467 | get_inotify_watch(watch); | |
468 | ||
469 | atomic_inc(&dev->user->inotify_watches); | |
470 | ||
471 | return watch; | |
472 | } | |
473 | ||
474 | /* | |
475 | * inotify_find_dev - find the watch associated with the given inode and dev | |
476 | * | |
d4f9af9d | 477 | * Callers must hold inode->inotify_mutex. |
0eeca283 RL |
478 | */ |
479 | static struct inotify_watch *inode_find_dev(struct inode *inode, | |
480 | struct inotify_device *dev) | |
481 | { | |
482 | struct inotify_watch *watch; | |
483 | ||
484 | list_for_each_entry(watch, &inode->inotify_watches, i_list) { | |
485 | if (watch->dev == dev) | |
486 | return watch; | |
487 | } | |
488 | ||
489 | return NULL; | |
490 | } | |
491 | ||
492 | /* | |
493 | * remove_watch_no_event - remove_watch() without the IN_IGNORED event. | |
494 | */ | |
495 | static void remove_watch_no_event(struct inotify_watch *watch, | |
496 | struct inotify_device *dev) | |
497 | { | |
498 | list_del(&watch->i_list); | |
499 | list_del(&watch->d_list); | |
500 | ||
c32ccd87 NP |
501 | if (!inotify_inode_watched(watch->inode)) |
502 | set_dentry_child_flags(watch->inode, 0); | |
503 | ||
0eeca283 RL |
504 | atomic_dec(&dev->user->inotify_watches); |
505 | idr_remove(&dev->idr, watch->wd); | |
506 | put_inotify_watch(watch); | |
507 | } | |
508 | ||
509 | /* | |
510 | * remove_watch - Remove a watch from both the device and the inode. Sends | |
511 | * the IN_IGNORED event to the given device signifying that the inode is no | |
512 | * longer watched. | |
513 | * | |
d4f9af9d | 514 | * Callers must hold both inode->inotify_mutex and dev->mutex. We drop a |
0eeca283 RL |
515 | * reference to the inode before returning. |
516 | * | |
517 | * The inode is not iput() so as to remain atomic. If the inode needs to be | |
518 | * iput(), the call returns one. Otherwise, it returns zero. | |
519 | */ | |
520 | static void remove_watch(struct inotify_watch *watch,struct inotify_device *dev) | |
521 | { | |
522 | inotify_dev_queue_event(dev, watch, IN_IGNORED, 0, NULL); | |
523 | remove_watch_no_event(watch, dev); | |
524 | } | |
525 | ||
c32ccd87 NP |
526 | /* Kernel API */ |
527 | ||
0eeca283 | 528 | /* |
c32ccd87 | 529 | * inotify_d_instantiate - instantiate dcache entry for inode |
0eeca283 | 530 | */ |
c32ccd87 | 531 | void inotify_d_instantiate(struct dentry *entry, struct inode *inode) |
0eeca283 | 532 | { |
c32ccd87 NP |
533 | struct dentry *parent; |
534 | ||
535 | if (!inode) | |
536 | return; | |
537 | ||
538 | WARN_ON(entry->d_flags & DCACHE_INOTIFY_PARENT_WATCHED); | |
539 | spin_lock(&entry->d_lock); | |
540 | parent = entry->d_parent; | |
091e881d | 541 | if (parent->d_inode && inotify_inode_watched(parent->d_inode)) |
c32ccd87 NP |
542 | entry->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; |
543 | spin_unlock(&entry->d_lock); | |
0eeca283 RL |
544 | } |
545 | ||
c32ccd87 NP |
546 | /* |
547 | * inotify_d_move - dcache entry has been moved | |
548 | */ | |
549 | void inotify_d_move(struct dentry *entry) | |
550 | { | |
551 | struct dentry *parent; | |
552 | ||
553 | parent = entry->d_parent; | |
554 | if (inotify_inode_watched(parent->d_inode)) | |
555 | entry->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; | |
556 | else | |
557 | entry->d_flags &= ~DCACHE_INOTIFY_PARENT_WATCHED; | |
558 | } | |
0eeca283 RL |
559 | |
560 | /** | |
561 | * inotify_inode_queue_event - queue an event to all watches on this inode | |
562 | * @inode: inode event is originating from | |
563 | * @mask: event mask describing this event | |
564 | * @cookie: cookie for synchronization, or zero | |
565 | * @name: filename, if any | |
566 | */ | |
567 | void inotify_inode_queue_event(struct inode *inode, u32 mask, u32 cookie, | |
568 | const char *name) | |
569 | { | |
570 | struct inotify_watch *watch, *next; | |
571 | ||
572 | if (!inotify_inode_watched(inode)) | |
573 | return; | |
574 | ||
d4f9af9d | 575 | mutex_lock(&inode->inotify_mutex); |
0eeca283 RL |
576 | list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) { |
577 | u32 watch_mask = watch->mask; | |
578 | if (watch_mask & mask) { | |
579 | struct inotify_device *dev = watch->dev; | |
580 | get_inotify_watch(watch); | |
d4f9af9d | 581 | mutex_lock(&dev->mutex); |
0eeca283 RL |
582 | inotify_dev_queue_event(dev, watch, mask, cookie, name); |
583 | if (watch_mask & IN_ONESHOT) | |
584 | remove_watch_no_event(watch, dev); | |
d4f9af9d | 585 | mutex_unlock(&dev->mutex); |
0eeca283 RL |
586 | put_inotify_watch(watch); |
587 | } | |
588 | } | |
d4f9af9d | 589 | mutex_unlock(&inode->inotify_mutex); |
0eeca283 RL |
590 | } |
591 | EXPORT_SYMBOL_GPL(inotify_inode_queue_event); | |
592 | ||
593 | /** | |
594 | * inotify_dentry_parent_queue_event - queue an event to a dentry's parent | |
595 | * @dentry: the dentry in question, we queue against this dentry's parent | |
596 | * @mask: event mask describing this event | |
597 | * @cookie: cookie for synchronization, or zero | |
598 | * @name: filename, if any | |
599 | */ | |
600 | void inotify_dentry_parent_queue_event(struct dentry *dentry, u32 mask, | |
601 | u32 cookie, const char *name) | |
602 | { | |
603 | struct dentry *parent; | |
604 | struct inode *inode; | |
605 | ||
c32ccd87 | 606 | if (!(dentry->d_flags & DCACHE_INOTIFY_PARENT_WATCHED)) |
820249ba JM |
607 | return; |
608 | ||
0eeca283 RL |
609 | spin_lock(&dentry->d_lock); |
610 | parent = dentry->d_parent; | |
611 | inode = parent->d_inode; | |
612 | ||
613 | if (inotify_inode_watched(inode)) { | |
614 | dget(parent); | |
615 | spin_unlock(&dentry->d_lock); | |
616 | inotify_inode_queue_event(inode, mask, cookie, name); | |
617 | dput(parent); | |
618 | } else | |
619 | spin_unlock(&dentry->d_lock); | |
620 | } | |
621 | EXPORT_SYMBOL_GPL(inotify_dentry_parent_queue_event); | |
622 | ||
623 | /** | |
624 | * inotify_get_cookie - return a unique cookie for use in synchronizing events. | |
625 | */ | |
626 | u32 inotify_get_cookie(void) | |
627 | { | |
628 | return atomic_inc_return(&inotify_cookie); | |
629 | } | |
630 | EXPORT_SYMBOL_GPL(inotify_get_cookie); | |
631 | ||
632 | /** | |
633 | * inotify_unmount_inodes - an sb is unmounting. handle any watched inodes. | |
634 | * @list: list of inodes being unmounted (sb->s_inodes) | |
635 | * | |
636 | * Called with inode_lock held, protecting the unmounting super block's list | |
f24075bd | 637 | * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay. |
0eeca283 RL |
638 | * We temporarily drop inode_lock, however, and CAN block. |
639 | */ | |
640 | void inotify_unmount_inodes(struct list_head *list) | |
641 | { | |
642 | struct inode *inode, *next_i, *need_iput = NULL; | |
643 | ||
644 | list_for_each_entry_safe(inode, next_i, list, i_sb_list) { | |
645 | struct inotify_watch *watch, *next_w; | |
646 | struct inode *need_iput_tmp; | |
647 | struct list_head *watches; | |
648 | ||
649 | /* | |
650 | * If i_count is zero, the inode cannot have any watches and | |
651 | * doing an __iget/iput with MS_ACTIVE clear would actually | |
652 | * evict all inodes with zero i_count from icache which is | |
653 | * unnecessarily violent and may in fact be illegal to do. | |
654 | */ | |
655 | if (!atomic_read(&inode->i_count)) | |
656 | continue; | |
657 | ||
658 | /* | |
659 | * We cannot __iget() an inode in state I_CLEAR, I_FREEING, or | |
660 | * I_WILL_FREE which is fine because by that point the inode | |
661 | * cannot have any associated watches. | |
662 | */ | |
663 | if (inode->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE)) | |
664 | continue; | |
665 | ||
666 | need_iput_tmp = need_iput; | |
667 | need_iput = NULL; | |
668 | /* In case the remove_watch() drops a reference. */ | |
669 | if (inode != need_iput_tmp) | |
670 | __iget(inode); | |
671 | else | |
672 | need_iput_tmp = NULL; | |
673 | /* In case the dropping of a reference would nuke next_i. */ | |
674 | if ((&next_i->i_sb_list != list) && | |
675 | atomic_read(&next_i->i_count) && | |
676 | !(next_i->i_state & (I_CLEAR | I_FREEING | | |
677 | I_WILL_FREE))) { | |
678 | __iget(next_i); | |
679 | need_iput = next_i; | |
680 | } | |
681 | ||
682 | /* | |
683 | * We can safely drop inode_lock here because we hold | |
684 | * references on both inode and next_i. Also no new inodes | |
685 | * will be added since the umount has begun. Finally, | |
f24075bd | 686 | * iprune_mutex keeps shrink_icache_memory() away. |
0eeca283 RL |
687 | */ |
688 | spin_unlock(&inode_lock); | |
689 | ||
690 | if (need_iput_tmp) | |
691 | iput(need_iput_tmp); | |
692 | ||
693 | /* for each watch, send IN_UNMOUNT and then remove it */ | |
d4f9af9d | 694 | mutex_lock(&inode->inotify_mutex); |
0eeca283 RL |
695 | watches = &inode->inotify_watches; |
696 | list_for_each_entry_safe(watch, next_w, watches, i_list) { | |
697 | struct inotify_device *dev = watch->dev; | |
d4f9af9d | 698 | mutex_lock(&dev->mutex); |
0eeca283 RL |
699 | inotify_dev_queue_event(dev, watch, IN_UNMOUNT,0,NULL); |
700 | remove_watch(watch, dev); | |
d4f9af9d | 701 | mutex_unlock(&dev->mutex); |
0eeca283 | 702 | } |
d4f9af9d | 703 | mutex_unlock(&inode->inotify_mutex); |
0eeca283 RL |
704 | iput(inode); |
705 | ||
706 | spin_lock(&inode_lock); | |
707 | } | |
708 | } | |
709 | EXPORT_SYMBOL_GPL(inotify_unmount_inodes); | |
710 | ||
711 | /** | |
712 | * inotify_inode_is_dead - an inode has been deleted, cleanup any watches | |
713 | * @inode: inode that is about to be removed | |
714 | */ | |
715 | void inotify_inode_is_dead(struct inode *inode) | |
716 | { | |
717 | struct inotify_watch *watch, *next; | |
718 | ||
d4f9af9d | 719 | mutex_lock(&inode->inotify_mutex); |
0eeca283 RL |
720 | list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) { |
721 | struct inotify_device *dev = watch->dev; | |
d4f9af9d | 722 | mutex_lock(&dev->mutex); |
0eeca283 | 723 | remove_watch(watch, dev); |
d4f9af9d | 724 | mutex_unlock(&dev->mutex); |
0eeca283 | 725 | } |
d4f9af9d | 726 | mutex_unlock(&inode->inotify_mutex); |
0eeca283 RL |
727 | } |
728 | EXPORT_SYMBOL_GPL(inotify_inode_is_dead); | |
729 | ||
730 | /* Device Interface */ | |
731 | ||
732 | static unsigned int inotify_poll(struct file *file, poll_table *wait) | |
733 | { | |
734 | struct inotify_device *dev = file->private_data; | |
735 | int ret = 0; | |
736 | ||
737 | poll_wait(file, &dev->wq, wait); | |
d4f9af9d | 738 | mutex_lock(&dev->mutex); |
0eeca283 RL |
739 | if (!list_empty(&dev->events)) |
740 | ret = POLLIN | POLLRDNORM; | |
d4f9af9d | 741 | mutex_unlock(&dev->mutex); |
0eeca283 RL |
742 | |
743 | return ret; | |
744 | } | |
745 | ||
746 | static ssize_t inotify_read(struct file *file, char __user *buf, | |
747 | size_t count, loff_t *pos) | |
748 | { | |
749 | size_t event_size = sizeof (struct inotify_event); | |
750 | struct inotify_device *dev; | |
751 | char __user *start; | |
752 | int ret; | |
753 | DEFINE_WAIT(wait); | |
754 | ||
755 | start = buf; | |
756 | dev = file->private_data; | |
757 | ||
758 | while (1) { | |
759 | int events; | |
760 | ||
761 | prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE); | |
762 | ||
d4f9af9d | 763 | mutex_lock(&dev->mutex); |
0eeca283 | 764 | events = !list_empty(&dev->events); |
d4f9af9d | 765 | mutex_unlock(&dev->mutex); |
0eeca283 RL |
766 | if (events) { |
767 | ret = 0; | |
768 | break; | |
769 | } | |
770 | ||
771 | if (file->f_flags & O_NONBLOCK) { | |
772 | ret = -EAGAIN; | |
773 | break; | |
774 | } | |
775 | ||
776 | if (signal_pending(current)) { | |
777 | ret = -EINTR; | |
778 | break; | |
779 | } | |
780 | ||
781 | schedule(); | |
782 | } | |
783 | ||
784 | finish_wait(&dev->wq, &wait); | |
785 | if (ret) | |
786 | return ret; | |
787 | ||
d4f9af9d | 788 | mutex_lock(&dev->mutex); |
0eeca283 RL |
789 | while (1) { |
790 | struct inotify_kernel_event *kevent; | |
791 | ||
792 | ret = buf - start; | |
793 | if (list_empty(&dev->events)) | |
794 | break; | |
795 | ||
796 | kevent = inotify_dev_get_event(dev); | |
797 | if (event_size + kevent->event.len > count) | |
798 | break; | |
799 | ||
800 | if (copy_to_user(buf, &kevent->event, event_size)) { | |
801 | ret = -EFAULT; | |
802 | break; | |
803 | } | |
804 | buf += event_size; | |
805 | count -= event_size; | |
806 | ||
807 | if (kevent->name) { | |
808 | if (copy_to_user(buf, kevent->name, kevent->event.len)){ | |
809 | ret = -EFAULT; | |
810 | break; | |
811 | } | |
812 | buf += kevent->event.len; | |
813 | count -= kevent->event.len; | |
814 | } | |
815 | ||
816 | remove_kevent(dev, kevent); | |
817 | } | |
d4f9af9d | 818 | mutex_unlock(&dev->mutex); |
0eeca283 RL |
819 | |
820 | return ret; | |
821 | } | |
822 | ||
823 | static int inotify_release(struct inode *ignored, struct file *file) | |
824 | { | |
825 | struct inotify_device *dev = file->private_data; | |
826 | ||
827 | /* | |
828 | * Destroy all of the watches on this device. Unfortunately, not very | |
829 | * pretty. We cannot do a simple iteration over the list, because we | |
830 | * do not know the inode until we iterate to the watch. But we need to | |
d4f9af9d | 831 | * hold inode->inotify_mutex before dev->mutex. The following works. |
0eeca283 RL |
832 | */ |
833 | while (1) { | |
834 | struct inotify_watch *watch; | |
835 | struct list_head *watches; | |
836 | struct inode *inode; | |
837 | ||
d4f9af9d | 838 | mutex_lock(&dev->mutex); |
0eeca283 RL |
839 | watches = &dev->watches; |
840 | if (list_empty(watches)) { | |
d4f9af9d | 841 | mutex_unlock(&dev->mutex); |
0eeca283 RL |
842 | break; |
843 | } | |
844 | watch = list_entry(watches->next, struct inotify_watch, d_list); | |
845 | get_inotify_watch(watch); | |
d4f9af9d | 846 | mutex_unlock(&dev->mutex); |
0eeca283 RL |
847 | |
848 | inode = watch->inode; | |
d4f9af9d IM |
849 | mutex_lock(&inode->inotify_mutex); |
850 | mutex_lock(&dev->mutex); | |
66055a4e AG |
851 | |
852 | /* make sure we didn't race with another list removal */ | |
853 | if (likely(idr_find(&dev->idr, watch->wd))) | |
854 | remove_watch_no_event(watch, dev); | |
855 | ||
d4f9af9d IM |
856 | mutex_unlock(&dev->mutex); |
857 | mutex_unlock(&inode->inotify_mutex); | |
0eeca283 RL |
858 | put_inotify_watch(watch); |
859 | } | |
860 | ||
861 | /* destroy all of the events on this device */ | |
d4f9af9d | 862 | mutex_lock(&dev->mutex); |
0eeca283 RL |
863 | while (!list_empty(&dev->events)) |
864 | inotify_dev_event_dequeue(dev); | |
d4f9af9d | 865 | mutex_unlock(&dev->mutex); |
0eeca283 | 866 | |
b680716e | 867 | /* free this device: the put matching the get in inotify_init() */ |
0eeca283 RL |
868 | put_inotify_dev(dev); |
869 | ||
870 | return 0; | |
871 | } | |
872 | ||
873 | /* | |
b680716e | 874 | * inotify_ignore - remove a given wd from this inotify instance. |
0eeca283 RL |
875 | * |
876 | * Can sleep. | |
877 | */ | |
878 | static int inotify_ignore(struct inotify_device *dev, s32 wd) | |
879 | { | |
880 | struct inotify_watch *watch; | |
881 | struct inode *inode; | |
882 | ||
d4f9af9d | 883 | mutex_lock(&dev->mutex); |
0eeca283 RL |
884 | watch = idr_find(&dev->idr, wd); |
885 | if (unlikely(!watch)) { | |
d4f9af9d | 886 | mutex_unlock(&dev->mutex); |
0eeca283 RL |
887 | return -EINVAL; |
888 | } | |
889 | get_inotify_watch(watch); | |
890 | inode = watch->inode; | |
d4f9af9d | 891 | mutex_unlock(&dev->mutex); |
0eeca283 | 892 | |
d4f9af9d IM |
893 | mutex_lock(&inode->inotify_mutex); |
894 | mutex_lock(&dev->mutex); | |
0eeca283 RL |
895 | |
896 | /* make sure that we did not race */ | |
d66fd908 | 897 | if (likely(idr_find(&dev->idr, wd) == watch)) |
0eeca283 RL |
898 | remove_watch(watch, dev); |
899 | ||
d4f9af9d IM |
900 | mutex_unlock(&dev->mutex); |
901 | mutex_unlock(&inode->inotify_mutex); | |
0eeca283 RL |
902 | put_inotify_watch(watch); |
903 | ||
904 | return 0; | |
905 | } | |
906 | ||
907 | static long inotify_ioctl(struct file *file, unsigned int cmd, | |
908 | unsigned long arg) | |
909 | { | |
910 | struct inotify_device *dev; | |
911 | void __user *p; | |
912 | int ret = -ENOTTY; | |
913 | ||
914 | dev = file->private_data; | |
915 | p = (void __user *) arg; | |
916 | ||
917 | switch (cmd) { | |
918 | case FIONREAD: | |
919 | ret = put_user(dev->queue_size, (int __user *) p); | |
920 | break; | |
921 | } | |
922 | ||
923 | return ret; | |
924 | } | |
925 | ||
4b6f5d20 | 926 | static const struct file_operations inotify_fops = { |
0eeca283 RL |
927 | .poll = inotify_poll, |
928 | .read = inotify_read, | |
929 | .release = inotify_release, | |
930 | .unlocked_ioctl = inotify_ioctl, | |
931 | .compat_ioctl = inotify_ioctl, | |
932 | }; | |
933 | ||
934 | asmlinkage long sys_inotify_init(void) | |
935 | { | |
936 | struct inotify_device *dev; | |
937 | struct user_struct *user; | |
b680716e RL |
938 | struct file *filp; |
939 | int fd, ret; | |
0eeca283 RL |
940 | |
941 | fd = get_unused_fd(); | |
b680716e RL |
942 | if (fd < 0) |
943 | return fd; | |
0eeca283 RL |
944 | |
945 | filp = get_empty_filp(); | |
946 | if (!filp) { | |
0eeca283 | 947 | ret = -ENFILE; |
5eb22cbc | 948 | goto out_put_fd; |
0eeca283 | 949 | } |
0eeca283 RL |
950 | |
951 | user = get_uid(current->user); | |
b680716e RL |
952 | if (unlikely(atomic_read(&user->inotify_devs) >= |
953 | inotify_max_user_instances)) { | |
0eeca283 | 954 | ret = -EMFILE; |
5eb22cbc | 955 | goto out_free_uid; |
0eeca283 RL |
956 | } |
957 | ||
958 | dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL); | |
959 | if (unlikely(!dev)) { | |
960 | ret = -ENOMEM; | |
5eb22cbc | 961 | goto out_free_uid; |
0eeca283 RL |
962 | } |
963 | ||
b680716e RL |
964 | filp->f_op = &inotify_fops; |
965 | filp->f_vfsmnt = mntget(inotify_mnt); | |
966 | filp->f_dentry = dget(inotify_mnt->mnt_root); | |
967 | filp->f_mapping = filp->f_dentry->d_inode->i_mapping; | |
968 | filp->f_mode = FMODE_READ; | |
969 | filp->f_flags = O_RDONLY; | |
970 | filp->private_data = dev; | |
971 | ||
0eeca283 RL |
972 | idr_init(&dev->idr); |
973 | INIT_LIST_HEAD(&dev->events); | |
974 | INIT_LIST_HEAD(&dev->watches); | |
975 | init_waitqueue_head(&dev->wq); | |
d4f9af9d | 976 | mutex_init(&dev->mutex); |
0eeca283 RL |
977 | dev->event_count = 0; |
978 | dev->queue_size = 0; | |
979 | dev->max_events = inotify_max_queued_events; | |
980 | dev->user = user; | |
b9c55d29 | 981 | dev->last_wd = 0; |
0eeca283 RL |
982 | atomic_set(&dev->count, 0); |
983 | ||
984 | get_inotify_dev(dev); | |
985 | atomic_inc(&user->inotify_devs); | |
b680716e | 986 | fd_install(fd, filp); |
0eeca283 | 987 | |
0eeca283 | 988 | return fd; |
5eb22cbc | 989 | out_free_uid: |
0eeca283 | 990 | free_uid(user); |
5eb22cbc RL |
991 | put_filp(filp); |
992 | out_put_fd: | |
993 | put_unused_fd(fd); | |
0eeca283 RL |
994 | return ret; |
995 | } | |
996 | ||
b680716e | 997 | asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) |
0eeca283 RL |
998 | { |
999 | struct inotify_watch *watch, *old; | |
1000 | struct inode *inode; | |
1001 | struct inotify_device *dev; | |
1002 | struct nameidata nd; | |
1003 | struct file *filp; | |
33ea2f52 | 1004 | int ret, fput_needed; |
7ea6040b | 1005 | int mask_add = 0; |
8140a500 | 1006 | unsigned flags = 0; |
0eeca283 | 1007 | |
33ea2f52 RL |
1008 | filp = fget_light(fd, &fput_needed); |
1009 | if (unlikely(!filp)) | |
0eeca283 RL |
1010 | return -EBADF; |
1011 | ||
783bc29b RL |
1012 | /* verify that this is indeed an inotify instance */ |
1013 | if (unlikely(filp->f_op != &inotify_fops)) { | |
1014 | ret = -EINVAL; | |
1015 | goto fput_and_out; | |
1016 | } | |
1017 | ||
8140a500 JM |
1018 | if (!(mask & IN_DONT_FOLLOW)) |
1019 | flags |= LOOKUP_FOLLOW; | |
1020 | if (mask & IN_ONLYDIR) | |
1021 | flags |= LOOKUP_DIRECTORY; | |
1022 | ||
1023 | ret = find_inode(path, &nd, flags); | |
b680716e | 1024 | if (unlikely(ret)) |
0eeca283 RL |
1025 | goto fput_and_out; |
1026 | ||
b680716e | 1027 | /* inode held in place by reference to nd; dev by fget on fd */ |
0eeca283 | 1028 | inode = nd.dentry->d_inode; |
b680716e | 1029 | dev = filp->private_data; |
0eeca283 | 1030 | |
d4f9af9d IM |
1031 | mutex_lock(&inode->inotify_mutex); |
1032 | mutex_lock(&dev->mutex); | |
0eeca283 | 1033 | |
7ea6040b JM |
1034 | if (mask & IN_MASK_ADD) |
1035 | mask_add = 1; | |
1036 | ||
0eeca283 | 1037 | /* don't let user-space set invalid bits: we don't want flags set */ |
b5173119 | 1038 | mask &= IN_ALL_EVENTS | IN_ONESHOT; |
b680716e | 1039 | if (unlikely(!mask)) { |
0eeca283 RL |
1040 | ret = -EINVAL; |
1041 | goto out; | |
1042 | } | |
1043 | ||
1044 | /* | |
1045 | * Handle the case of re-adding a watch on an (inode,dev) pair that we | |
1046 | * are already watching. We just update the mask and return its wd. | |
1047 | */ | |
1048 | old = inode_find_dev(inode, dev); | |
1049 | if (unlikely(old)) { | |
7ea6040b JM |
1050 | if (mask_add) |
1051 | old->mask |= mask; | |
1052 | else | |
1053 | old->mask = mask; | |
0eeca283 RL |
1054 | ret = old->wd; |
1055 | goto out; | |
1056 | } | |
1057 | ||
1058 | watch = create_watch(dev, mask, inode); | |
1059 | if (unlikely(IS_ERR(watch))) { | |
1060 | ret = PTR_ERR(watch); | |
1061 | goto out; | |
1062 | } | |
1063 | ||
c32ccd87 NP |
1064 | if (!inotify_inode_watched(inode)) |
1065 | set_dentry_child_flags(inode, 1); | |
1066 | ||
0eeca283 RL |
1067 | /* Add the watch to the device's and the inode's list */ |
1068 | list_add(&watch->d_list, &dev->watches); | |
1069 | list_add(&watch->i_list, &inode->inotify_watches); | |
1070 | ret = watch->wd; | |
1071 | out: | |
d4f9af9d IM |
1072 | mutex_unlock(&dev->mutex); |
1073 | mutex_unlock(&inode->inotify_mutex); | |
5eb22cbc | 1074 | path_release(&nd); |
0eeca283 | 1075 | fput_and_out: |
33ea2f52 | 1076 | fput_light(filp, fput_needed); |
0eeca283 RL |
1077 | return ret; |
1078 | } | |
1079 | ||
1080 | asmlinkage long sys_inotify_rm_watch(int fd, u32 wd) | |
1081 | { | |
1082 | struct file *filp; | |
1083 | struct inotify_device *dev; | |
33ea2f52 | 1084 | int ret, fput_needed; |
0eeca283 | 1085 | |
33ea2f52 RL |
1086 | filp = fget_light(fd, &fput_needed); |
1087 | if (unlikely(!filp)) | |
0eeca283 | 1088 | return -EBADF; |
783bc29b RL |
1089 | |
1090 | /* verify that this is indeed an inotify instance */ | |
1091 | if (unlikely(filp->f_op != &inotify_fops)) { | |
1092 | ret = -EINVAL; | |
1093 | goto out; | |
1094 | } | |
1095 | ||
0eeca283 | 1096 | dev = filp->private_data; |
9a556e89 | 1097 | ret = inotify_ignore(dev, wd); |
9a556e89 | 1098 | |
783bc29b RL |
1099 | out: |
1100 | fput_light(filp, fput_needed); | |
0eeca283 RL |
1101 | return ret; |
1102 | } | |
1103 | ||
1104 | static struct super_block * | |
1105 | inotify_get_sb(struct file_system_type *fs_type, int flags, | |
1106 | const char *dev_name, void *data) | |
1107 | { | |
1108 | return get_sb_pseudo(fs_type, "inotify", NULL, 0xBAD1DEA); | |
1109 | } | |
1110 | ||
1111 | static struct file_system_type inotify_fs_type = { | |
1112 | .name = "inotifyfs", | |
1113 | .get_sb = inotify_get_sb, | |
1114 | .kill_sb = kill_anon_super, | |
1115 | }; | |
1116 | ||
1117 | /* | |
b680716e | 1118 | * inotify_setup - Our initialization function. Note that we cannnot return |
0eeca283 RL |
1119 | * error because we have compiled-in VFS hooks. So an (unlikely) failure here |
1120 | * must result in panic(). | |
1121 | */ | |
b680716e | 1122 | static int __init inotify_setup(void) |
0eeca283 | 1123 | { |
e5ca844a RL |
1124 | int ret; |
1125 | ||
1126 | ret = register_filesystem(&inotify_fs_type); | |
1127 | if (unlikely(ret)) | |
1128 | panic("inotify: register_filesystem returned %d!\n", ret); | |
1129 | ||
0eeca283 | 1130 | inotify_mnt = kern_mount(&inotify_fs_type); |
89373de7 | 1131 | if (IS_ERR(inotify_mnt)) |
e5ca844a | 1132 | panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt)); |
0eeca283 | 1133 | |
1b2ccf0c RL |
1134 | inotify_max_queued_events = 16384; |
1135 | inotify_max_user_instances = 128; | |
0eeca283 RL |
1136 | inotify_max_user_watches = 8192; |
1137 | ||
1138 | atomic_set(&inotify_cookie, 0); | |
1139 | ||
1140 | watch_cachep = kmem_cache_create("inotify_watch_cache", | |
1141 | sizeof(struct inotify_watch), | |
1142 | 0, SLAB_PANIC, NULL, NULL); | |
1143 | event_cachep = kmem_cache_create("inotify_event_cache", | |
1144 | sizeof(struct inotify_kernel_event), | |
1145 | 0, SLAB_PANIC, NULL, NULL); | |
1146 | ||
0eeca283 RL |
1147 | return 0; |
1148 | } | |
1149 | ||
b680716e | 1150 | module_init(inotify_setup); |