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[linux/fpc-iii.git] / fs / notify / inotify / inotify_user.c
blob4506486974336d6451abc0658de78c0c06bdec9a
1 /*
2 * fs/inotify_user.c - inotify support for userspace
4 * Authors:
5 * John McCutchan <ttb@tentacle.dhs.org>
6 * Robert Love <rml@novell.com>
8 * Copyright (C) 2005 John McCutchan
9 * Copyright 2006 Hewlett-Packard Development Company, L.P.
11 * Copyright (C) 2009 Eric Paris <Red Hat Inc>
12 * inotify was largely rewriten to make use of the fsnotify infrastructure
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License as published by the
16 * Free Software Foundation; either version 2, or (at your option) any
17 * later version.
19 * This program is distributed in the hope that it will be useful, but
20 * WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 * General Public License for more details.
25 #include <linux/file.h>
26 #include <linux/fs.h> /* struct inode */
27 #include <linux/fsnotify_backend.h>
28 #include <linux/idr.h>
29 #include <linux/init.h> /* module_init */
30 #include <linux/inotify.h>
31 #include <linux/kernel.h> /* roundup() */
32 #include <linux/namei.h> /* LOOKUP_FOLLOW */
33 #include <linux/sched.h> /* struct user */
34 #include <linux/slab.h> /* struct kmem_cache */
35 #include <linux/syscalls.h>
36 #include <linux/types.h>
37 #include <linux/anon_inodes.h>
38 #include <linux/uaccess.h>
39 #include <linux/poll.h>
40 #include <linux/wait.h>
42 #include "inotify.h"
43 #include "../fdinfo.h"
45 #include <asm/ioctls.h>
47 /* these are configurable via /proc/sys/fs/inotify/ */
48 static int inotify_max_user_instances __read_mostly;
49 static int inotify_max_queued_events __read_mostly;
50 static int inotify_max_user_watches __read_mostly;
52 static struct kmem_cache *inotify_inode_mark_cachep __read_mostly;
54 #ifdef CONFIG_SYSCTL
56 #include <linux/sysctl.h>
58 static int zero;
60 struct ctl_table inotify_table[] = {
62 .procname = "max_user_instances",
63 .data = &inotify_max_user_instances,
64 .maxlen = sizeof(int),
65 .mode = 0644,
66 .proc_handler = proc_dointvec_minmax,
67 .extra1 = &zero,
70 .procname = "max_user_watches",
71 .data = &inotify_max_user_watches,
72 .maxlen = sizeof(int),
73 .mode = 0644,
74 .proc_handler = proc_dointvec_minmax,
75 .extra1 = &zero,
78 .procname = "max_queued_events",
79 .data = &inotify_max_queued_events,
80 .maxlen = sizeof(int),
81 .mode = 0644,
82 .proc_handler = proc_dointvec_minmax,
83 .extra1 = &zero
85 { }
87 #endif /* CONFIG_SYSCTL */
89 static inline __u32 inotify_arg_to_mask(u32 arg)
91 __u32 mask;
94 * everything should accept their own ignored, cares about children,
95 * and should receive events when the inode is unmounted
97 mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD | FS_UNMOUNT);
99 /* mask off the flags used to open the fd */
100 mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT | IN_EXCL_UNLINK));
102 return mask;
105 static inline u32 inotify_mask_to_arg(__u32 mask)
107 return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED |
108 IN_Q_OVERFLOW);
111 /* intofiy userspace file descriptor functions */
112 static unsigned int inotify_poll(struct file *file, poll_table *wait)
114 struct fsnotify_group *group = file->private_data;
115 int ret = 0;
117 poll_wait(file, &group->notification_waitq, wait);
118 mutex_lock(&group->notification_mutex);
119 if (!fsnotify_notify_queue_is_empty(group))
120 ret = POLLIN | POLLRDNORM;
121 mutex_unlock(&group->notification_mutex);
123 return ret;
126 static int round_event_name_len(struct fsnotify_event *fsn_event)
128 struct inotify_event_info *event;
130 event = INOTIFY_E(fsn_event);
131 if (!event->name_len)
132 return 0;
133 return roundup(event->name_len + 1, sizeof(struct inotify_event));
137 * Get an inotify_kernel_event if one exists and is small
138 * enough to fit in "count". Return an error pointer if
139 * not large enough.
141 * Called with the group->notification_mutex held.
143 static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
144 size_t count)
146 size_t event_size = sizeof(struct inotify_event);
147 struct fsnotify_event *event;
149 if (fsnotify_notify_queue_is_empty(group))
150 return NULL;
152 event = fsnotify_peek_first_event(group);
154 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
156 event_size += round_event_name_len(event);
157 if (event_size > count)
158 return ERR_PTR(-EINVAL);
160 /* held the notification_mutex the whole time, so this is the
161 * same event we peeked above */
162 fsnotify_remove_first_event(group);
164 return event;
168 * Copy an event to user space, returning how much we copied.
170 * We already checked that the event size is smaller than the
171 * buffer we had in "get_one_event()" above.
173 static ssize_t copy_event_to_user(struct fsnotify_group *group,
174 struct fsnotify_event *fsn_event,
175 char __user *buf)
177 struct inotify_event inotify_event;
178 struct inotify_event_info *event;
179 size_t event_size = sizeof(struct inotify_event);
180 size_t name_len;
181 size_t pad_name_len;
183 pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event);
185 event = INOTIFY_E(fsn_event);
186 name_len = event->name_len;
188 * round up name length so it is a multiple of event_size
189 * plus an extra byte for the terminating '\0'.
191 pad_name_len = round_event_name_len(fsn_event);
192 inotify_event.len = pad_name_len;
193 inotify_event.mask = inotify_mask_to_arg(fsn_event->mask);
194 inotify_event.wd = event->wd;
195 inotify_event.cookie = event->sync_cookie;
197 /* send the main event */
198 if (copy_to_user(buf, &inotify_event, event_size))
199 return -EFAULT;
201 buf += event_size;
204 * fsnotify only stores the pathname, so here we have to send the pathname
205 * and then pad that pathname out to a multiple of sizeof(inotify_event)
206 * with zeros.
208 if (pad_name_len) {
209 /* copy the path name */
210 if (copy_to_user(buf, event->name, name_len))
211 return -EFAULT;
212 buf += name_len;
214 /* fill userspace with 0's */
215 if (clear_user(buf, pad_name_len - name_len))
216 return -EFAULT;
217 event_size += pad_name_len;
220 return event_size;
223 static ssize_t inotify_read(struct file *file, char __user *buf,
224 size_t count, loff_t *pos)
226 struct fsnotify_group *group;
227 struct fsnotify_event *kevent;
228 char __user *start;
229 int ret;
230 DEFINE_WAIT_FUNC(wait, woken_wake_function);
232 start = buf;
233 group = file->private_data;
235 add_wait_queue(&group->notification_waitq, &wait);
236 while (1) {
237 mutex_lock(&group->notification_mutex);
238 kevent = get_one_event(group, count);
239 mutex_unlock(&group->notification_mutex);
241 pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent);
243 if (kevent) {
244 ret = PTR_ERR(kevent);
245 if (IS_ERR(kevent))
246 break;
247 ret = copy_event_to_user(group, kevent, buf);
248 fsnotify_destroy_event(group, kevent);
249 if (ret < 0)
250 break;
251 buf += ret;
252 count -= ret;
253 continue;
256 ret = -EAGAIN;
257 if (file->f_flags & O_NONBLOCK)
258 break;
259 ret = -ERESTARTSYS;
260 if (signal_pending(current))
261 break;
263 if (start != buf)
264 break;
266 wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
268 remove_wait_queue(&group->notification_waitq, &wait);
270 if (start != buf && ret != -EFAULT)
271 ret = buf - start;
272 return ret;
275 static int inotify_release(struct inode *ignored, struct file *file)
277 struct fsnotify_group *group = file->private_data;
279 pr_debug("%s: group=%p\n", __func__, group);
281 /* free this group, matching get was inotify_init->fsnotify_obtain_group */
282 fsnotify_destroy_group(group);
284 return 0;
287 static long inotify_ioctl(struct file *file, unsigned int cmd,
288 unsigned long arg)
290 struct fsnotify_group *group;
291 struct fsnotify_event *fsn_event;
292 void __user *p;
293 int ret = -ENOTTY;
294 size_t send_len = 0;
296 group = file->private_data;
297 p = (void __user *) arg;
299 pr_debug("%s: group=%p cmd=%u\n", __func__, group, cmd);
301 switch (cmd) {
302 case FIONREAD:
303 mutex_lock(&group->notification_mutex);
304 list_for_each_entry(fsn_event, &group->notification_list,
305 list) {
306 send_len += sizeof(struct inotify_event);
307 send_len += round_event_name_len(fsn_event);
309 mutex_unlock(&group->notification_mutex);
310 ret = put_user(send_len, (int __user *) p);
311 break;
314 return ret;
317 static const struct file_operations inotify_fops = {
318 .show_fdinfo = inotify_show_fdinfo,
319 .poll = inotify_poll,
320 .read = inotify_read,
321 .fasync = fsnotify_fasync,
322 .release = inotify_release,
323 .unlocked_ioctl = inotify_ioctl,
324 .compat_ioctl = inotify_ioctl,
325 .llseek = noop_llseek,
330 * find_inode - resolve a user-given path to a specific inode
332 static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags)
334 int error;
336 error = user_path_at(AT_FDCWD, dirname, flags, path);
337 if (error)
338 return error;
339 /* you can only watch an inode if you have read permissions on it */
340 error = inode_permission(path->dentry->d_inode, MAY_READ);
341 if (error)
342 path_put(path);
343 return error;
346 static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock,
347 struct inotify_inode_mark *i_mark)
349 int ret;
351 idr_preload(GFP_KERNEL);
352 spin_lock(idr_lock);
354 ret = idr_alloc_cyclic(idr, i_mark, 1, 0, GFP_NOWAIT);
355 if (ret >= 0) {
356 /* we added the mark to the idr, take a reference */
357 i_mark->wd = ret;
358 fsnotify_get_mark(&i_mark->fsn_mark);
361 spin_unlock(idr_lock);
362 idr_preload_end();
363 return ret < 0 ? ret : 0;
366 static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group,
367 int wd)
369 struct idr *idr = &group->inotify_data.idr;
370 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
371 struct inotify_inode_mark *i_mark;
373 assert_spin_locked(idr_lock);
375 i_mark = idr_find(idr, wd);
376 if (i_mark) {
377 struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark;
379 fsnotify_get_mark(fsn_mark);
380 /* One ref for being in the idr, one ref we just took */
381 BUG_ON(atomic_read(&fsn_mark->refcnt) < 2);
384 return i_mark;
387 static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group,
388 int wd)
390 struct inotify_inode_mark *i_mark;
391 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
393 spin_lock(idr_lock);
394 i_mark = inotify_idr_find_locked(group, wd);
395 spin_unlock(idr_lock);
397 return i_mark;
400 static void do_inotify_remove_from_idr(struct fsnotify_group *group,
401 struct inotify_inode_mark *i_mark)
403 struct idr *idr = &group->inotify_data.idr;
404 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
405 int wd = i_mark->wd;
407 assert_spin_locked(idr_lock);
409 idr_remove(idr, wd);
411 /* removed from the idr, drop that ref */
412 fsnotify_put_mark(&i_mark->fsn_mark);
416 * Remove the mark from the idr (if present) and drop the reference
417 * on the mark because it was in the idr.
419 static void inotify_remove_from_idr(struct fsnotify_group *group,
420 struct inotify_inode_mark *i_mark)
422 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
423 struct inotify_inode_mark *found_i_mark = NULL;
424 int wd;
426 spin_lock(idr_lock);
427 wd = i_mark->wd;
430 * does this i_mark think it is in the idr? we shouldn't get called
431 * if it wasn't....
433 if (wd == -1) {
434 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
435 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
436 i_mark->fsn_mark.group, i_mark->fsn_mark.inode);
437 goto out;
440 /* Lets look in the idr to see if we find it */
441 found_i_mark = inotify_idr_find_locked(group, wd);
442 if (unlikely(!found_i_mark)) {
443 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
444 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
445 i_mark->fsn_mark.group, i_mark->fsn_mark.inode);
446 goto out;
450 * We found an mark in the idr at the right wd, but it's
451 * not the mark we were told to remove. eparis seriously
452 * fucked up somewhere.
454 if (unlikely(found_i_mark != i_mark)) {
455 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p "
456 "mark->inode=%p found_i_mark=%p found_i_mark->wd=%d "
457 "found_i_mark->group=%p found_i_mark->inode=%p\n",
458 __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group,
459 i_mark->fsn_mark.inode, found_i_mark, found_i_mark->wd,
460 found_i_mark->fsn_mark.group,
461 found_i_mark->fsn_mark.inode);
462 goto out;
466 * One ref for being in the idr
467 * one ref held by the caller trying to kill us
468 * one ref grabbed by inotify_idr_find
470 if (unlikely(atomic_read(&i_mark->fsn_mark.refcnt) < 3)) {
471 printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
472 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
473 i_mark->fsn_mark.group, i_mark->fsn_mark.inode);
474 /* we can't really recover with bad ref cnting.. */
475 BUG();
478 do_inotify_remove_from_idr(group, i_mark);
479 out:
480 /* match the ref taken by inotify_idr_find_locked() */
481 if (found_i_mark)
482 fsnotify_put_mark(&found_i_mark->fsn_mark);
483 i_mark->wd = -1;
484 spin_unlock(idr_lock);
488 * Send IN_IGNORED for this wd, remove this wd from the idr.
490 void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark,
491 struct fsnotify_group *group)
493 struct inotify_inode_mark *i_mark;
495 /* Queue ignore event for the watch */
496 inotify_handle_event(group, NULL, fsn_mark, NULL, FS_IN_IGNORED,
497 NULL, FSNOTIFY_EVENT_NONE, NULL, 0);
499 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
500 /* remove this mark from the idr */
501 inotify_remove_from_idr(group, i_mark);
503 atomic_dec(&group->inotify_data.user->inotify_watches);
506 /* ding dong the mark is dead */
507 static void inotify_free_mark(struct fsnotify_mark *fsn_mark)
509 struct inotify_inode_mark *i_mark;
511 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
513 kmem_cache_free(inotify_inode_mark_cachep, i_mark);
516 static int inotify_update_existing_watch(struct fsnotify_group *group,
517 struct inode *inode,
518 u32 arg)
520 struct fsnotify_mark *fsn_mark;
521 struct inotify_inode_mark *i_mark;
522 __u32 old_mask, new_mask;
523 __u32 mask;
524 int add = (arg & IN_MASK_ADD);
525 int ret;
527 mask = inotify_arg_to_mask(arg);
529 fsn_mark = fsnotify_find_inode_mark(group, inode);
530 if (!fsn_mark)
531 return -ENOENT;
533 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
535 spin_lock(&fsn_mark->lock);
537 old_mask = fsn_mark->mask;
538 if (add)
539 fsnotify_set_mark_mask_locked(fsn_mark, (fsn_mark->mask | mask));
540 else
541 fsnotify_set_mark_mask_locked(fsn_mark, mask);
542 new_mask = fsn_mark->mask;
544 spin_unlock(&fsn_mark->lock);
546 if (old_mask != new_mask) {
547 /* more bits in old than in new? */
548 int dropped = (old_mask & ~new_mask);
549 /* more bits in this fsn_mark than the inode's mask? */
550 int do_inode = (new_mask & ~inode->i_fsnotify_mask);
552 /* update the inode with this new fsn_mark */
553 if (dropped || do_inode)
554 fsnotify_recalc_inode_mask(inode);
558 /* return the wd */
559 ret = i_mark->wd;
561 /* match the get from fsnotify_find_mark() */
562 fsnotify_put_mark(fsn_mark);
564 return ret;
567 static int inotify_new_watch(struct fsnotify_group *group,
568 struct inode *inode,
569 u32 arg)
571 struct inotify_inode_mark *tmp_i_mark;
572 __u32 mask;
573 int ret;
574 struct idr *idr = &group->inotify_data.idr;
575 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
577 mask = inotify_arg_to_mask(arg);
579 tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
580 if (unlikely(!tmp_i_mark))
581 return -ENOMEM;
583 fsnotify_init_mark(&tmp_i_mark->fsn_mark, inotify_free_mark);
584 tmp_i_mark->fsn_mark.mask = mask;
585 tmp_i_mark->wd = -1;
587 ret = -ENOSPC;
588 if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
589 goto out_err;
591 ret = inotify_add_to_idr(idr, idr_lock, tmp_i_mark);
592 if (ret)
593 goto out_err;
595 /* we are on the idr, now get on the inode */
596 ret = fsnotify_add_mark_locked(&tmp_i_mark->fsn_mark, group, inode,
597 NULL, 0);
598 if (ret) {
599 /* we failed to get on the inode, get off the idr */
600 inotify_remove_from_idr(group, tmp_i_mark);
601 goto out_err;
604 /* increment the number of watches the user has */
605 atomic_inc(&group->inotify_data.user->inotify_watches);
607 /* return the watch descriptor for this new mark */
608 ret = tmp_i_mark->wd;
610 out_err:
611 /* match the ref from fsnotify_init_mark() */
612 fsnotify_put_mark(&tmp_i_mark->fsn_mark);
614 return ret;
617 static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
619 int ret = 0;
621 mutex_lock(&group->mark_mutex);
622 /* try to update and existing watch with the new arg */
623 ret = inotify_update_existing_watch(group, inode, arg);
624 /* no mark present, try to add a new one */
625 if (ret == -ENOENT)
626 ret = inotify_new_watch(group, inode, arg);
627 mutex_unlock(&group->mark_mutex);
629 return ret;
632 static struct fsnotify_group *inotify_new_group(unsigned int max_events)
634 struct fsnotify_group *group;
635 struct inotify_event_info *oevent;
637 group = fsnotify_alloc_group(&inotify_fsnotify_ops);
638 if (IS_ERR(group))
639 return group;
641 oevent = kmalloc(sizeof(struct inotify_event_info), GFP_KERNEL);
642 if (unlikely(!oevent)) {
643 fsnotify_destroy_group(group);
644 return ERR_PTR(-ENOMEM);
646 group->overflow_event = &oevent->fse;
647 fsnotify_init_event(group->overflow_event, NULL, FS_Q_OVERFLOW);
648 oevent->wd = -1;
649 oevent->sync_cookie = 0;
650 oevent->name_len = 0;
652 group->max_events = max_events;
654 spin_lock_init(&group->inotify_data.idr_lock);
655 idr_init(&group->inotify_data.idr);
656 group->inotify_data.user = get_current_user();
658 if (atomic_inc_return(&group->inotify_data.user->inotify_devs) >
659 inotify_max_user_instances) {
660 fsnotify_destroy_group(group);
661 return ERR_PTR(-EMFILE);
664 return group;
668 /* inotify syscalls */
669 SYSCALL_DEFINE1(inotify_init1, int, flags)
671 struct fsnotify_group *group;
672 int ret;
674 /* Check the IN_* constants for consistency. */
675 BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC);
676 BUILD_BUG_ON(IN_NONBLOCK != O_NONBLOCK);
678 if (flags & ~(IN_CLOEXEC | IN_NONBLOCK))
679 return -EINVAL;
681 /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */
682 group = inotify_new_group(inotify_max_queued_events);
683 if (IS_ERR(group))
684 return PTR_ERR(group);
686 ret = anon_inode_getfd("inotify", &inotify_fops, group,
687 O_RDONLY | flags);
688 if (ret < 0)
689 fsnotify_destroy_group(group);
691 return ret;
694 SYSCALL_DEFINE0(inotify_init)
696 return sys_inotify_init1(0);
699 SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname,
700 u32, mask)
702 struct fsnotify_group *group;
703 struct inode *inode;
704 struct path path;
705 struct fd f;
706 int ret;
707 unsigned flags = 0;
709 /* don't allow invalid bits: we don't want flags set */
710 if (unlikely(!(mask & ALL_INOTIFY_BITS)))
711 return -EINVAL;
713 f = fdget(fd);
714 if (unlikely(!f.file))
715 return -EBADF;
717 /* verify that this is indeed an inotify instance */
718 if (unlikely(f.file->f_op != &inotify_fops)) {
719 ret = -EINVAL;
720 goto fput_and_out;
723 if (!(mask & IN_DONT_FOLLOW))
724 flags |= LOOKUP_FOLLOW;
725 if (mask & IN_ONLYDIR)
726 flags |= LOOKUP_DIRECTORY;
728 ret = inotify_find_inode(pathname, &path, flags);
729 if (ret)
730 goto fput_and_out;
732 /* inode held in place by reference to path; group by fget on fd */
733 inode = path.dentry->d_inode;
734 group = f.file->private_data;
736 /* create/update an inode mark */
737 ret = inotify_update_watch(group, inode, mask);
738 path_put(&path);
739 fput_and_out:
740 fdput(f);
741 return ret;
744 SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd)
746 struct fsnotify_group *group;
747 struct inotify_inode_mark *i_mark;
748 struct fd f;
749 int ret = 0;
751 f = fdget(fd);
752 if (unlikely(!f.file))
753 return -EBADF;
755 /* verify that this is indeed an inotify instance */
756 ret = -EINVAL;
757 if (unlikely(f.file->f_op != &inotify_fops))
758 goto out;
760 group = f.file->private_data;
762 ret = -EINVAL;
763 i_mark = inotify_idr_find(group, wd);
764 if (unlikely(!i_mark))
765 goto out;
767 ret = 0;
769 fsnotify_destroy_mark(&i_mark->fsn_mark, group);
771 /* match ref taken by inotify_idr_find */
772 fsnotify_put_mark(&i_mark->fsn_mark);
774 out:
775 fdput(f);
776 return ret;
780 * inotify_user_setup - Our initialization function. Note that we cannot return
781 * error because we have compiled-in VFS hooks. So an (unlikely) failure here
782 * must result in panic().
784 static int __init inotify_user_setup(void)
786 BUILD_BUG_ON(IN_ACCESS != FS_ACCESS);
787 BUILD_BUG_ON(IN_MODIFY != FS_MODIFY);
788 BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB);
789 BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE);
790 BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
791 BUILD_BUG_ON(IN_OPEN != FS_OPEN);
792 BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM);
793 BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO);
794 BUILD_BUG_ON(IN_CREATE != FS_CREATE);
795 BUILD_BUG_ON(IN_DELETE != FS_DELETE);
796 BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF);
797 BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF);
798 BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT);
799 BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW);
800 BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED);
801 BUILD_BUG_ON(IN_EXCL_UNLINK != FS_EXCL_UNLINK);
802 BUILD_BUG_ON(IN_ISDIR != FS_ISDIR);
803 BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT);
805 BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21);
807 inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC);
809 inotify_max_queued_events = 16384;
810 inotify_max_user_instances = 128;
811 inotify_max_user_watches = 8192;
813 return 0;
815 module_init(inotify_user_setup);