MIPS: Fix GCC-4.6 'set but not used' warning in arch/mips/mm/init.c
[linux/fpc-iii.git] / fs / notify / inotify / inotify_user.c
blob4cd5d5d78f9fa2b85f38bd9422efc3d387780295
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"
44 #include <asm/ioctls.h>
46 /* these are configurable via /proc/sys/fs/inotify/ */
47 static int inotify_max_user_instances __read_mostly;
48 static int inotify_max_queued_events __read_mostly;
49 static int inotify_max_user_watches __read_mostly;
51 static struct kmem_cache *inotify_inode_mark_cachep __read_mostly;
52 struct kmem_cache *event_priv_cachep __read_mostly;
54 #ifdef CONFIG_SYSCTL
56 #include <linux/sysctl.h>
58 static int zero;
60 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;
127 * Get an inotify_kernel_event if one exists and is small
128 * enough to fit in "count". Return an error pointer if
129 * not large enough.
131 * Called with the group->notification_mutex held.
133 static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
134 size_t count)
136 size_t event_size = sizeof(struct inotify_event);
137 struct fsnotify_event *event;
139 if (fsnotify_notify_queue_is_empty(group))
140 return NULL;
142 event = fsnotify_peek_notify_event(group);
144 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
146 if (event->name_len)
147 event_size += roundup(event->name_len + 1, event_size);
149 if (event_size > count)
150 return ERR_PTR(-EINVAL);
152 /* held the notification_mutex the whole time, so this is the
153 * same event we peeked above */
154 fsnotify_remove_notify_event(group);
156 return event;
160 * Copy an event to user space, returning how much we copied.
162 * We already checked that the event size is smaller than the
163 * buffer we had in "get_one_event()" above.
165 static ssize_t copy_event_to_user(struct fsnotify_group *group,
166 struct fsnotify_event *event,
167 char __user *buf)
169 struct inotify_event inotify_event;
170 struct fsnotify_event_private_data *fsn_priv;
171 struct inotify_event_private_data *priv;
172 size_t event_size = sizeof(struct inotify_event);
173 size_t name_len = 0;
175 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
177 /* we get the inotify watch descriptor from the event private data */
178 spin_lock(&event->lock);
179 fsn_priv = fsnotify_remove_priv_from_event(group, event);
180 spin_unlock(&event->lock);
182 if (!fsn_priv)
183 inotify_event.wd = -1;
184 else {
185 priv = container_of(fsn_priv, struct inotify_event_private_data,
186 fsnotify_event_priv_data);
187 inotify_event.wd = priv->wd;
188 inotify_free_event_priv(fsn_priv);
192 * round up event->name_len so it is a multiple of event_size
193 * plus an extra byte for the terminating '\0'.
195 if (event->name_len)
196 name_len = roundup(event->name_len + 1, event_size);
197 inotify_event.len = name_len;
199 inotify_event.mask = inotify_mask_to_arg(event->mask);
200 inotify_event.cookie = event->sync_cookie;
202 /* send the main event */
203 if (copy_to_user(buf, &inotify_event, event_size))
204 return -EFAULT;
206 buf += event_size;
209 * fsnotify only stores the pathname, so here we have to send the pathname
210 * and then pad that pathname out to a multiple of sizeof(inotify_event)
211 * with zeros. I get my zeros from the nul_inotify_event.
213 if (name_len) {
214 unsigned int len_to_zero = name_len - event->name_len;
215 /* copy the path name */
216 if (copy_to_user(buf, event->file_name, event->name_len))
217 return -EFAULT;
218 buf += event->name_len;
220 /* fill userspace with 0's */
221 if (clear_user(buf, len_to_zero))
222 return -EFAULT;
223 buf += len_to_zero;
224 event_size += name_len;
227 return event_size;
230 static ssize_t inotify_read(struct file *file, char __user *buf,
231 size_t count, loff_t *pos)
233 struct fsnotify_group *group;
234 struct fsnotify_event *kevent;
235 char __user *start;
236 int ret;
237 DEFINE_WAIT(wait);
239 start = buf;
240 group = file->private_data;
242 while (1) {
243 prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
245 mutex_lock(&group->notification_mutex);
246 kevent = get_one_event(group, count);
247 mutex_unlock(&group->notification_mutex);
249 pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent);
251 if (kevent) {
252 ret = PTR_ERR(kevent);
253 if (IS_ERR(kevent))
254 break;
255 ret = copy_event_to_user(group, kevent, buf);
256 fsnotify_put_event(kevent);
257 if (ret < 0)
258 break;
259 buf += ret;
260 count -= ret;
261 continue;
264 ret = -EAGAIN;
265 if (file->f_flags & O_NONBLOCK)
266 break;
267 ret = -EINTR;
268 if (signal_pending(current))
269 break;
271 if (start != buf)
272 break;
274 schedule();
277 finish_wait(&group->notification_waitq, &wait);
278 if (start != buf && ret != -EFAULT)
279 ret = buf - start;
280 return ret;
283 static int inotify_fasync(int fd, struct file *file, int on)
285 struct fsnotify_group *group = file->private_data;
287 return fasync_helper(fd, file, on, &group->inotify_data.fa) >= 0 ? 0 : -EIO;
290 static int inotify_release(struct inode *ignored, struct file *file)
292 struct fsnotify_group *group = file->private_data;
293 struct user_struct *user = group->inotify_data.user;
295 pr_debug("%s: group=%p\n", __func__, group);
297 fsnotify_clear_marks_by_group(group);
299 /* free this group, matching get was inotify_init->fsnotify_obtain_group */
300 fsnotify_put_group(group);
302 atomic_dec(&user->inotify_devs);
304 return 0;
307 static long inotify_ioctl(struct file *file, unsigned int cmd,
308 unsigned long arg)
310 struct fsnotify_group *group;
311 struct fsnotify_event_holder *holder;
312 struct fsnotify_event *event;
313 void __user *p;
314 int ret = -ENOTTY;
315 size_t send_len = 0;
317 group = file->private_data;
318 p = (void __user *) arg;
320 pr_debug("%s: group=%p cmd=%u\n", __func__, group, cmd);
322 switch (cmd) {
323 case FIONREAD:
324 mutex_lock(&group->notification_mutex);
325 list_for_each_entry(holder, &group->notification_list, event_list) {
326 event = holder->event;
327 send_len += sizeof(struct inotify_event);
328 if (event->name_len)
329 send_len += roundup(event->name_len + 1,
330 sizeof(struct inotify_event));
332 mutex_unlock(&group->notification_mutex);
333 ret = put_user(send_len, (int __user *) p);
334 break;
337 return ret;
340 static const struct file_operations inotify_fops = {
341 .poll = inotify_poll,
342 .read = inotify_read,
343 .fasync = inotify_fasync,
344 .release = inotify_release,
345 .unlocked_ioctl = inotify_ioctl,
346 .compat_ioctl = inotify_ioctl,
347 .llseek = noop_llseek,
352 * find_inode - resolve a user-given path to a specific inode
354 static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags)
356 int error;
358 error = user_path_at(AT_FDCWD, dirname, flags, path);
359 if (error)
360 return error;
361 /* you can only watch an inode if you have read permissions on it */
362 error = inode_permission(path->dentry->d_inode, MAY_READ);
363 if (error)
364 path_put(path);
365 return error;
368 static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock,
369 int *last_wd,
370 struct inotify_inode_mark *i_mark)
372 int ret;
374 do {
375 if (unlikely(!idr_pre_get(idr, GFP_KERNEL)))
376 return -ENOMEM;
378 spin_lock(idr_lock);
379 ret = idr_get_new_above(idr, i_mark, *last_wd + 1,
380 &i_mark->wd);
381 /* we added the mark to the idr, take a reference */
382 if (!ret) {
383 *last_wd = i_mark->wd;
384 fsnotify_get_mark(&i_mark->fsn_mark);
386 spin_unlock(idr_lock);
387 } while (ret == -EAGAIN);
389 return ret;
392 static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group,
393 int wd)
395 struct idr *idr = &group->inotify_data.idr;
396 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
397 struct inotify_inode_mark *i_mark;
399 assert_spin_locked(idr_lock);
401 i_mark = idr_find(idr, wd);
402 if (i_mark) {
403 struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark;
405 fsnotify_get_mark(fsn_mark);
406 /* One ref for being in the idr, one ref we just took */
407 BUG_ON(atomic_read(&fsn_mark->refcnt) < 2);
410 return i_mark;
413 static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group,
414 int wd)
416 struct inotify_inode_mark *i_mark;
417 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
419 spin_lock(idr_lock);
420 i_mark = inotify_idr_find_locked(group, wd);
421 spin_unlock(idr_lock);
423 return i_mark;
426 static void do_inotify_remove_from_idr(struct fsnotify_group *group,
427 struct inotify_inode_mark *i_mark)
429 struct idr *idr = &group->inotify_data.idr;
430 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
431 int wd = i_mark->wd;
433 assert_spin_locked(idr_lock);
435 idr_remove(idr, wd);
437 /* removed from the idr, drop that ref */
438 fsnotify_put_mark(&i_mark->fsn_mark);
442 * Remove the mark from the idr (if present) and drop the reference
443 * on the mark because it was in the idr.
445 static void inotify_remove_from_idr(struct fsnotify_group *group,
446 struct inotify_inode_mark *i_mark)
448 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
449 struct inotify_inode_mark *found_i_mark = NULL;
450 int wd;
452 spin_lock(idr_lock);
453 wd = i_mark->wd;
456 * does this i_mark think it is in the idr? we shouldn't get called
457 * if it wasn't....
459 if (wd == -1) {
460 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
461 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
462 i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode);
463 goto out;
466 /* Lets look in the idr to see if we find it */
467 found_i_mark = inotify_idr_find_locked(group, wd);
468 if (unlikely(!found_i_mark)) {
469 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
470 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
471 i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode);
472 goto out;
476 * We found an mark in the idr at the right wd, but it's
477 * not the mark we were told to remove. eparis seriously
478 * fucked up somewhere.
480 if (unlikely(found_i_mark != i_mark)) {
481 WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p "
482 "mark->inode=%p found_i_mark=%p found_i_mark->wd=%d "
483 "found_i_mark->group=%p found_i_mark->inode=%p\n",
484 __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group,
485 i_mark->fsn_mark.i.inode, found_i_mark, found_i_mark->wd,
486 found_i_mark->fsn_mark.group,
487 found_i_mark->fsn_mark.i.inode);
488 goto out;
492 * One ref for being in the idr
493 * one ref held by the caller trying to kill us
494 * one ref grabbed by inotify_idr_find
496 if (unlikely(atomic_read(&i_mark->fsn_mark.refcnt) < 3)) {
497 printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p"
498 " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd,
499 i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode);
500 /* we can't really recover with bad ref cnting.. */
501 BUG();
504 do_inotify_remove_from_idr(group, i_mark);
505 out:
506 /* match the ref taken by inotify_idr_find_locked() */
507 if (found_i_mark)
508 fsnotify_put_mark(&found_i_mark->fsn_mark);
509 i_mark->wd = -1;
510 spin_unlock(idr_lock);
514 * Send IN_IGNORED for this wd, remove this wd from the idr.
516 void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark,
517 struct fsnotify_group *group)
519 struct inotify_inode_mark *i_mark;
520 struct fsnotify_event *ignored_event, *notify_event;
521 struct inotify_event_private_data *event_priv;
522 struct fsnotify_event_private_data *fsn_event_priv;
523 int ret;
525 ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL,
526 FSNOTIFY_EVENT_NONE, NULL, 0,
527 GFP_NOFS);
528 if (!ignored_event)
529 return;
531 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
533 event_priv = kmem_cache_alloc(event_priv_cachep, GFP_NOFS);
534 if (unlikely(!event_priv))
535 goto skip_send_ignore;
537 fsn_event_priv = &event_priv->fsnotify_event_priv_data;
539 fsn_event_priv->group = group;
540 event_priv->wd = i_mark->wd;
542 notify_event = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv, NULL);
543 if (notify_event) {
544 if (IS_ERR(notify_event))
545 ret = PTR_ERR(notify_event);
546 else
547 fsnotify_put_event(notify_event);
548 inotify_free_event_priv(fsn_event_priv);
551 skip_send_ignore:
553 /* matches the reference taken when the event was created */
554 fsnotify_put_event(ignored_event);
556 /* remove this mark from the idr */
557 inotify_remove_from_idr(group, i_mark);
559 atomic_dec(&group->inotify_data.user->inotify_watches);
562 /* ding dong the mark is dead */
563 static void inotify_free_mark(struct fsnotify_mark *fsn_mark)
565 struct inotify_inode_mark *i_mark;
567 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
569 kmem_cache_free(inotify_inode_mark_cachep, i_mark);
572 static int inotify_update_existing_watch(struct fsnotify_group *group,
573 struct inode *inode,
574 u32 arg)
576 struct fsnotify_mark *fsn_mark;
577 struct inotify_inode_mark *i_mark;
578 __u32 old_mask, new_mask;
579 __u32 mask;
580 int add = (arg & IN_MASK_ADD);
581 int ret;
583 /* don't allow invalid bits: we don't want flags set */
584 mask = inotify_arg_to_mask(arg);
585 if (unlikely(!(mask & IN_ALL_EVENTS)))
586 return -EINVAL;
588 fsn_mark = fsnotify_find_inode_mark(group, inode);
589 if (!fsn_mark)
590 return -ENOENT;
592 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
594 spin_lock(&fsn_mark->lock);
596 old_mask = fsn_mark->mask;
597 if (add)
598 fsnotify_set_mark_mask_locked(fsn_mark, (fsn_mark->mask | mask));
599 else
600 fsnotify_set_mark_mask_locked(fsn_mark, mask);
601 new_mask = fsn_mark->mask;
603 spin_unlock(&fsn_mark->lock);
605 if (old_mask != new_mask) {
606 /* more bits in old than in new? */
607 int dropped = (old_mask & ~new_mask);
608 /* more bits in this fsn_mark than the inode's mask? */
609 int do_inode = (new_mask & ~inode->i_fsnotify_mask);
611 /* update the inode with this new fsn_mark */
612 if (dropped || do_inode)
613 fsnotify_recalc_inode_mask(inode);
617 /* return the wd */
618 ret = i_mark->wd;
620 /* match the get from fsnotify_find_mark() */
621 fsnotify_put_mark(fsn_mark);
623 return ret;
626 static int inotify_new_watch(struct fsnotify_group *group,
627 struct inode *inode,
628 u32 arg)
630 struct inotify_inode_mark *tmp_i_mark;
631 __u32 mask;
632 int ret;
633 struct idr *idr = &group->inotify_data.idr;
634 spinlock_t *idr_lock = &group->inotify_data.idr_lock;
636 /* don't allow invalid bits: we don't want flags set */
637 mask = inotify_arg_to_mask(arg);
638 if (unlikely(!(mask & IN_ALL_EVENTS)))
639 return -EINVAL;
641 tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
642 if (unlikely(!tmp_i_mark))
643 return -ENOMEM;
645 fsnotify_init_mark(&tmp_i_mark->fsn_mark, inotify_free_mark);
646 tmp_i_mark->fsn_mark.mask = mask;
647 tmp_i_mark->wd = -1;
649 ret = -ENOSPC;
650 if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
651 goto out_err;
653 ret = inotify_add_to_idr(idr, idr_lock, &group->inotify_data.last_wd,
654 tmp_i_mark);
655 if (ret)
656 goto out_err;
658 /* we are on the idr, now get on the inode */
659 ret = fsnotify_add_mark(&tmp_i_mark->fsn_mark, group, inode, NULL, 0);
660 if (ret) {
661 /* we failed to get on the inode, get off the idr */
662 inotify_remove_from_idr(group, tmp_i_mark);
663 goto out_err;
666 /* increment the number of watches the user has */
667 atomic_inc(&group->inotify_data.user->inotify_watches);
669 /* return the watch descriptor for this new mark */
670 ret = tmp_i_mark->wd;
672 out_err:
673 /* match the ref from fsnotify_init_mark() */
674 fsnotify_put_mark(&tmp_i_mark->fsn_mark);
676 return ret;
679 static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
681 int ret = 0;
683 retry:
684 /* try to update and existing watch with the new arg */
685 ret = inotify_update_existing_watch(group, inode, arg);
686 /* no mark present, try to add a new one */
687 if (ret == -ENOENT)
688 ret = inotify_new_watch(group, inode, arg);
690 * inotify_new_watch could race with another thread which did an
691 * inotify_new_watch between the update_existing and the add watch
692 * here, go back and try to update an existing mark again.
694 if (ret == -EEXIST)
695 goto retry;
697 return ret;
700 static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events)
702 struct fsnotify_group *group;
704 group = fsnotify_alloc_group(&inotify_fsnotify_ops);
705 if (IS_ERR(group))
706 return group;
708 group->max_events = max_events;
710 spin_lock_init(&group->inotify_data.idr_lock);
711 idr_init(&group->inotify_data.idr);
712 group->inotify_data.last_wd = 0;
713 group->inotify_data.user = user;
714 group->inotify_data.fa = NULL;
716 return group;
720 /* inotify syscalls */
721 SYSCALL_DEFINE1(inotify_init1, int, flags)
723 struct fsnotify_group *group;
724 struct user_struct *user;
725 int ret;
727 /* Check the IN_* constants for consistency. */
728 BUILD_BUG_ON(IN_CLOEXEC != O_CLOEXEC);
729 BUILD_BUG_ON(IN_NONBLOCK != O_NONBLOCK);
731 if (flags & ~(IN_CLOEXEC | IN_NONBLOCK))
732 return -EINVAL;
734 user = get_current_user();
735 if (unlikely(atomic_read(&user->inotify_devs) >=
736 inotify_max_user_instances)) {
737 ret = -EMFILE;
738 goto out_free_uid;
741 /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */
742 group = inotify_new_group(user, inotify_max_queued_events);
743 if (IS_ERR(group)) {
744 ret = PTR_ERR(group);
745 goto out_free_uid;
748 atomic_inc(&user->inotify_devs);
750 ret = anon_inode_getfd("inotify", &inotify_fops, group,
751 O_RDONLY | flags);
752 if (ret >= 0)
753 return ret;
755 fsnotify_put_group(group);
756 atomic_dec(&user->inotify_devs);
757 out_free_uid:
758 free_uid(user);
759 return ret;
762 SYSCALL_DEFINE0(inotify_init)
764 return sys_inotify_init1(0);
767 SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname,
768 u32, mask)
770 struct fsnotify_group *group;
771 struct inode *inode;
772 struct path path;
773 struct file *filp;
774 int ret, fput_needed;
775 unsigned flags = 0;
777 filp = fget_light(fd, &fput_needed);
778 if (unlikely(!filp))
779 return -EBADF;
781 /* verify that this is indeed an inotify instance */
782 if (unlikely(filp->f_op != &inotify_fops)) {
783 ret = -EINVAL;
784 goto fput_and_out;
787 if (!(mask & IN_DONT_FOLLOW))
788 flags |= LOOKUP_FOLLOW;
789 if (mask & IN_ONLYDIR)
790 flags |= LOOKUP_DIRECTORY;
792 ret = inotify_find_inode(pathname, &path, flags);
793 if (ret)
794 goto fput_and_out;
796 /* inode held in place by reference to path; group by fget on fd */
797 inode = path.dentry->d_inode;
798 group = filp->private_data;
800 /* create/update an inode mark */
801 ret = inotify_update_watch(group, inode, mask);
802 path_put(&path);
803 fput_and_out:
804 fput_light(filp, fput_needed);
805 return ret;
808 SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd)
810 struct fsnotify_group *group;
811 struct inotify_inode_mark *i_mark;
812 struct file *filp;
813 int ret = 0, fput_needed;
815 filp = fget_light(fd, &fput_needed);
816 if (unlikely(!filp))
817 return -EBADF;
819 /* verify that this is indeed an inotify instance */
820 ret = -EINVAL;
821 if (unlikely(filp->f_op != &inotify_fops))
822 goto out;
824 group = filp->private_data;
826 ret = -EINVAL;
827 i_mark = inotify_idr_find(group, wd);
828 if (unlikely(!i_mark))
829 goto out;
831 ret = 0;
833 fsnotify_destroy_mark(&i_mark->fsn_mark);
835 /* match ref taken by inotify_idr_find */
836 fsnotify_put_mark(&i_mark->fsn_mark);
838 out:
839 fput_light(filp, fput_needed);
840 return ret;
844 * inotify_user_setup - Our initialization function. Note that we cannnot return
845 * error because we have compiled-in VFS hooks. So an (unlikely) failure here
846 * must result in panic().
848 static int __init inotify_user_setup(void)
850 BUILD_BUG_ON(IN_ACCESS != FS_ACCESS);
851 BUILD_BUG_ON(IN_MODIFY != FS_MODIFY);
852 BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB);
853 BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE);
854 BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
855 BUILD_BUG_ON(IN_OPEN != FS_OPEN);
856 BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM);
857 BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO);
858 BUILD_BUG_ON(IN_CREATE != FS_CREATE);
859 BUILD_BUG_ON(IN_DELETE != FS_DELETE);
860 BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF);
861 BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF);
862 BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT);
863 BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW);
864 BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED);
865 BUILD_BUG_ON(IN_EXCL_UNLINK != FS_EXCL_UNLINK);
866 BUILD_BUG_ON(IN_ISDIR != FS_ISDIR);
867 BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT);
869 BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21);
871 inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC);
872 event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC);
874 inotify_max_queued_events = 16384;
875 inotify_max_user_instances = 128;
876 inotify_max_user_watches = 8192;
878 return 0;
880 module_init(inotify_user_setup);