[mirror_ubuntu-zesty-kernel.git] / fs / notify / fsnotify.c

/*
 *  Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/dcache.h>
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/srcu.h>

#include <linux/fsnotify_backend.h>
#include "fsnotify.h"

/*
 * Clear all of the marks on an inode when it is being evicted from core
 */
void __fsnotify_inode_delete(struct inode *inode)
{
	fsnotify_clear_marks_by_inode(inode);
}
EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);

void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
{
	fsnotify_clear_marks_by_mount(mnt);
}

/*
 * Given an inode, first check if we care what happens to our children.  Inotify
 * and dnotify both tell their parents about events.  If we care about any event
 * on a child we run all of our children and set a dentry flag saying that the
 * parent cares.  Thus when an event happens on a child it can quickly tell if
 * if there is a need to find a parent and send the event to the parent.
 */
void __fsnotify_update_child_dentry_flags(struct inode *inode)
{
	struct dentry *alias;
	int watched;

	if (!S_ISDIR(inode->i_mode))
		return;

	/* determine if the children should tell inode about their events */
	watched = fsnotify_inode_watches_children(inode);

	spin_lock(&inode->i_lock);
	/* run all of the dentries associated with this inode.  Since this is a
	 * directory, there damn well better only be one item on this list */
	hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
		struct dentry *child;

		/* run all of the children of the original inode and fix their
		 * d_flags to indicate parental interest (their parent is the
		 * original inode) */
		spin_lock(&alias->d_lock);
		list_for_each_entry(child, &alias->d_subdirs, d_child) {
			if (!child->d_inode)
				continue;

			spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
			if (watched)
				child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
			else
				child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
			spin_unlock(&child->d_lock);
		}
		spin_unlock(&alias->d_lock);
	}
	spin_unlock(&inode->i_lock);
}

/* Notify this dentry's parent about a child's events. */
int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask)
{
	struct dentry *parent;
	struct inode *p_inode;
	int ret = 0;

	if (!dentry)
		dentry = path->dentry;

	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
		return 0;

	parent = dget_parent(dentry);
	p_inode = parent->d_inode;

	if (unlikely(!fsnotify_inode_watches_children(p_inode)))
		__fsnotify_update_child_dentry_flags(p_inode);
	else if (p_inode->i_fsnotify_mask & mask) {
		struct name_snapshot name;

		/* we are notifying a parent so come up with the new mask which
		 * specifies these are events which came from a child. */
		mask |= FS_EVENT_ON_CHILD;

		take_dentry_name_snapshot(&name, dentry);
		if (path)
			ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
				       name.name, 0);
		else
			ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
				       name.name, 0);
		release_dentry_name_snapshot(&name);
	}

	dput(parent);

	return ret;
}
EXPORT_SYMBOL_GPL(__fsnotify_parent);

static int send_to_group(struct inode *to_tell,
			 struct fsnotify_mark *inode_mark,
			 struct fsnotify_mark *vfsmount_mark,
			 __u32 mask, const void *data,
			 int data_is, u32 cookie,
			 const unsigned char *file_name)
{
	struct fsnotify_group *group = NULL;
	__u32 inode_test_mask = 0;
	__u32 vfsmount_test_mask = 0;

	if (unlikely(!inode_mark && !vfsmount_mark)) {
		BUG();
		return 0;
	}

	/* clear ignored on inode modification */
	if (mask & FS_MODIFY) {
		if (inode_mark &&
		    !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
			inode_mark->ignored_mask = 0;
		if (vfsmount_mark &&
		    !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
			vfsmount_mark->ignored_mask = 0;
	}

	/* does the inode mark tell us to do something? */
	if (inode_mark) {
		group = inode_mark->group;
		inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
		inode_test_mask &= inode_mark->mask;
		inode_test_mask &= ~inode_mark->ignored_mask;
	}

	/* does the vfsmount_mark tell us to do something? */
	if (vfsmount_mark) {
		vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
		group = vfsmount_mark->group;
		vfsmount_test_mask &= vfsmount_mark->mask;
		vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
		if (inode_mark)
			vfsmount_test_mask &= ~inode_mark->ignored_mask;
	}

	pr_debug("%s: group=%p to_tell=%p mask=%x inode_mark=%p"
		 " inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x"
		 " data=%p data_is=%d cookie=%d\n",
		 __func__, group, to_tell, mask, inode_mark,
		 inode_test_mask, vfsmount_mark, vfsmount_test_mask, data,
		 data_is, cookie);

	if (!inode_test_mask && !vfsmount_test_mask)
		return 0;

	return group->ops->handle_event(group, to_tell, inode_mark,
					vfsmount_mark, mask, data, data_is,
					file_name, cookie);
}

/*
 * This is the main call to fsnotify.  The VFS calls into hook specific functions
 * in linux/fsnotify.h.  Those functions then in turn call here.  Here will call
 * out to all of the registered fsnotify_group.  Those groups can then use the
 * notification event in whatever means they feel necessary.
 */
int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
	     const unsigned char *file_name, u32 cookie)
{
	struct hlist_node *inode_node = NULL, *vfsmount_node = NULL;
	struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL;
	struct fsnotify_group *inode_group, *vfsmount_group;
	struct mount *mnt;
	int idx, ret = 0;
	/* global tests shouldn't care about events on child only the specific event */
	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);

	if (data_is == FSNOTIFY_EVENT_PATH)
		mnt = real_mount(((const struct path *)data)->mnt);
	else
		mnt = NULL;

	/*
	 * Optimization: srcu_read_lock() has a memory barrier which can
	 * be expensive.  It protects walking the *_fsnotify_marks lists.
	 * However, if we do not walk the lists, we do not have to do
	 * SRCU because we have no references to any objects and do not
	 * need SRCU to keep them "alive".
	 */
	if (hlist_empty(&to_tell->i_fsnotify_marks) &&
	    (!mnt || hlist_empty(&mnt->mnt_fsnotify_marks)))
		return 0;
	/*
	 * if this is a modify event we may need to clear the ignored masks
	 * otherwise return if neither the inode nor the vfsmount care about
	 * this type of event.
	 */
	if (!(mask & FS_MODIFY) &&
	    !(test_mask & to_tell->i_fsnotify_mask) &&
	    !(mnt && test_mask & mnt->mnt_fsnotify_mask))
		return 0;

	idx = srcu_read_lock(&fsnotify_mark_srcu);

	if ((mask & FS_MODIFY) ||
	    (test_mask & to_tell->i_fsnotify_mask))
		inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
					      &fsnotify_mark_srcu);

	if (mnt && ((mask & FS_MODIFY) ||
		    (test_mask & mnt->mnt_fsnotify_mask))) {
		vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first,
						 &fsnotify_mark_srcu);
		inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
					      &fsnotify_mark_srcu);
	}

	/*
	 * We need to merge inode & vfsmount mark lists so that inode mark
	 * ignore masks are properly reflected for mount mark notifications.
	 * That's why this traversal is so complicated...
	 */
	while (inode_node || vfsmount_node) {
		inode_group = NULL;
		inode_mark = NULL;
		vfsmount_group = NULL;
		vfsmount_mark = NULL;

		if (inode_node) {
			inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
						 struct fsnotify_mark, obj_list);
			inode_group = inode_mark->group;
		}

		if (vfsmount_node) {
			vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
						    struct fsnotify_mark, obj_list);
			vfsmount_group = vfsmount_mark->group;
		}

		if (inode_group && vfsmount_group) {
			int cmp = fsnotify_compare_groups(inode_group,
							  vfsmount_group);
			if (cmp > 0) {
				inode_group = NULL;
				inode_mark = NULL;
			} else if (cmp < 0) {
				vfsmount_group = NULL;
				vfsmount_mark = NULL;
			}
		}
		ret = send_to_group(to_tell, inode_mark, vfsmount_mark, mask,
				    data, data_is, cookie, file_name);

		if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
			goto out;

		if (inode_group)
			inode_node = srcu_dereference(inode_node->next,
						      &fsnotify_mark_srcu);
		if (vfsmount_group)
			vfsmount_node = srcu_dereference(vfsmount_node->next,
							 &fsnotify_mark_srcu);
	}
	ret = 0;
out:
	srcu_read_unlock(&fsnotify_mark_srcu, idx);

	return ret;
}
EXPORT_SYMBOL_GPL(fsnotify);

static __init int fsnotify_init(void)
{
	int ret;

	BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);

	ret = init_srcu_struct(&fsnotify_mark_srcu);
	if (ret)
		panic("initializing fsnotify_mark_srcu");

	return 0;
}
core_initcall(fsnotify_init);
Commit	Line	Data
90586523 EP	1	/*
	2	* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2, or (at your option)
	7	* any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; see the file COPYING. If not, write to
	16	* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
	17	*/
	18
	19	#include <linux/dcache.h>
	20	#include <linux/fs.h>
5a0e3ad6	21	#include <linux/gfp.h>
90586523 EP	22	#include <linux/init.h>
90586523 EP	23	#include <linux/module.h>
7131485a	24	#include <linux/mount.h>
90586523 EP	25	#include <linux/srcu.h>
	26
	27	#include <linux/fsnotify_backend.h>
	28	#include "fsnotify.h"
	29
3be25f49 EP	30	/*
	31	* Clear all of the marks on an inode when it is being evicted from core
	32	*/
	33	void __fsnotify_inode_delete(struct inode *inode)
	34	{
	35	fsnotify_clear_marks_by_inode(inode);
	36	}
	37	EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
	38
ca9c726e AG	39	void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
	40	{
	41	fsnotify_clear_marks_by_mount(mnt);
	42	}
	43
c28f7e56 EP	44	/*
	45	* Given an inode, first check if we care what happens to our children. Inotify
	46	* and dnotify both tell their parents about events. If we care about any event
	47	* on a child we run all of our children and set a dentry flag saying that the
	48	* parent cares. Thus when an event happens on a child it can quickly tell if
	49	* if there is a need to find a parent and send the event to the parent.
	50	*/
	51	void __fsnotify_update_child_dentry_flags(struct inode *inode)
	52	{
	53	struct dentry *alias;
	54	int watched;
	55
	56	if (!S_ISDIR(inode->i_mode))
	57	return;
	58
	59	/* determine if the children should tell inode about their events */
	60	watched = fsnotify_inode_watches_children(inode);
	61
873feea0	62	spin_lock(&inode->i_lock);
c28f7e56 EP	63	/* run all of the dentries associated with this inode. Since this is a
c28f7e56 EP	64	* directory, there damn well better only be one item on this list */
946e51f2	65	hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
c28f7e56 EP	66	struct dentry *child;
	67
	68	/* run all of the children of the original inode and fix their
	69	* d_flags to indicate parental interest (their parent is the
	70	* original inode) */
2fd6b7f5	71	spin_lock(&alias->d_lock);
946e51f2	72	list_for_each_entry(child, &alias->d_subdirs, d_child) {
c28f7e56 EP	73	if (!child->d_inode)
	74	continue;
	75
2fd6b7f5	76	spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
c28f7e56 EP	77	if (watched)
	78	child->d_flags \|= DCACHE_FSNOTIFY_PARENT_WATCHED;
	79	else
	80	child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
	81	spin_unlock(&child->d_lock);
	82	}
2fd6b7f5	83	spin_unlock(&alias->d_lock);
c28f7e56	84	}
873feea0	85	spin_unlock(&inode->i_lock);
c28f7e56 EP	86	}
	87
	88	/* Notify this dentry's parent about a child's events. */
12c7f9dc	89	int __fsnotify_parent(const struct path path, struct dentry dentry, __u32 mask)
c28f7e56 EP	90	{
	91	struct dentry *parent;
	92	struct inode *p_inode;
52420392	93	int ret = 0;
c28f7e56	94
72acc854	95	if (!dentry)
2069601b	96	dentry = path->dentry;
28c60e37	97
c28f7e56	98	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
52420392	99	return 0;
c28f7e56	100
4d4eb366	101	parent = dget_parent(dentry);
c28f7e56 EP	102	p_inode = parent->d_inode;
c28f7e56 EP	103
4d4eb366 CH	104	if (unlikely(!fsnotify_inode_watches_children(p_inode)))
	105	__fsnotify_update_child_dentry_flags(p_inode);
	106	else if (p_inode->i_fsnotify_mask & mask) {
5e675887 AV	107	struct name_snapshot name;
5e675887 AV	108
c28f7e56 EP	109	/* we are notifying a parent so come up with the new mask which
	110	* specifies these are events which came from a child. */
	111	mask \|= FS_EVENT_ON_CHILD;
	112
5e675887	113	take_dentry_name_snapshot(&name, dentry);
2069601b	114	if (path)
52420392	115	ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
5e675887	116	name.name, 0);
28c60e37	117	else
52420392	118	ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
5e675887 AV	119	name.name, 0);
5e675887 AV	120	release_dentry_name_snapshot(&name);
c28f7e56 EP	121	}
c28f7e56 EP	122
4d4eb366	123	dput(parent);
52420392 EP	124
52420392 EP	125	return ret;
c28f7e56 EP	126	}
	127	EXPORT_SYMBOL_GPL(__fsnotify_parent);
	128
fd657170	129	static int send_to_group(struct inode *to_tell,
ce8f76fb EP	130	struct fsnotify_mark *inode_mark,
ce8f76fb EP	131	struct fsnotify_mark *vfsmount_mark,
e637835e	132	__u32 mask, const void *data,
613a807f	133	int data_is, u32 cookie,
7053aee2	134	const unsigned char *file_name)
7131485a	135	{
faa9560a	136	struct fsnotify_group *group = NULL;
84e1ab4d EP	137	__u32 inode_test_mask = 0;
84e1ab4d EP	138	__u32 vfsmount_test_mask = 0;
613a807f	139
faa9560a EP	140	if (unlikely(!inode_mark && !vfsmount_mark)) {
	141	BUG();
	142	return 0;
	143	}
ce8f76fb EP	144
	145	/* clear ignored on inode modification */
	146	if (mask & FS_MODIFY) {
	147	if (inode_mark &&
	148	!(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
	149	inode_mark->ignored_mask = 0;
	150	if (vfsmount_mark &&
	151	!(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
	152	vfsmount_mark->ignored_mask = 0;
	153	}
5ba08e2e	154
ce8f76fb EP	155	/* does the inode mark tell us to do something? */
ce8f76fb EP	156	if (inode_mark) {
faa9560a	157	group = inode_mark->group;
84e1ab4d	158	inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
ce8f76fb EP	159	inode_test_mask &= inode_mark->mask;
	160	inode_test_mask &= ~inode_mark->ignored_mask;
	161	}
613a807f	162
ce8f76fb EP	163	/* does the vfsmount_mark tell us to do something? */
ce8f76fb EP	164	if (vfsmount_mark) {
84e1ab4d	165	vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
faa9560a	166	group = vfsmount_mark->group;
ce8f76fb EP	167	vfsmount_test_mask &= vfsmount_mark->mask;
	168	vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
	169	if (inode_mark)
	170	vfsmount_test_mask &= ~inode_mark->ignored_mask;
	171	}
	172
fd657170	173	pr_debug("%s: group=%p to_tell=%p mask=%x inode_mark=%p"
84e1ab4d	174	" inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x"
7053aee2	175	" data=%p data_is=%d cookie=%d\n",
fd657170	176	__func__, group, to_tell, mask, inode_mark,
84e1ab4d	177	inode_test_mask, vfsmount_mark, vfsmount_test_mask, data,
7053aee2	178	data_is, cookie);
faa9560a	179
ce8f76fb	180	if (!inode_test_mask && !vfsmount_test_mask)
613a807f EP	181	return 0;
613a807f EP	182
7053aee2 JK	183	return group->ops->handle_event(group, to_tell, inode_mark,
7053aee2 JK	184	vfsmount_mark, mask, data, data_is,
45a22f4c	185	file_name, cookie);
7131485a EP	186	}
7131485a EP	187
90586523 EP	188	/*
	189	* This is the main call to fsnotify. The VFS calls into hook specific functions
	190	* in linux/fsnotify.h. Those functions then in turn call here. Here will call
	191	* out to all of the registered fsnotify_group. Those groups can then use the
	192	* notification event in whatever means they feel necessary.
	193	*/
e637835e	194	int fsnotify(struct inode to_tell, __u32 mask, const void data, int data_is,
c4ec54b4	195	const unsigned char *file_name, u32 cookie)
90586523	196	{
84e1ab4d	197	struct hlist_node inode_node = NULL, vfsmount_node = NULL;
613a807f EP	198	struct fsnotify_mark inode_mark = NULL, vfsmount_mark = NULL;
613a807f EP	199	struct fsnotify_group inode_group, vfsmount_group;
c63181e6	200	struct mount *mnt;
c4ec54b4	201	int idx, ret = 0;
e42e2773 EP	202	/* global tests shouldn't care about events on child only the specific event */
e42e2773 EP	203	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
90586523	204
2069601b	205	if (data_is == FSNOTIFY_EVENT_PATH)
e637835e	206	mnt = real_mount(((const struct path *)data)->mnt);
613a807f EP	207	else
	208	mnt = NULL;
	209
7c49b861 DH	210	/*
	211	* Optimization: srcu_read_lock() has a memory barrier which can
	212	* be expensive. It protects walking the *_fsnotify_marks lists.
	213	* However, if we do not walk the lists, we do not have to do
	214	* SRCU because we have no references to any objects and do not
	215	* need SRCU to keep them "alive".
	216	*/
	217	if (hlist_empty(&to_tell->i_fsnotify_marks) &&
	218	(!mnt \|\| hlist_empty(&mnt->mnt_fsnotify_marks)))
	219	return 0;
613a807f EP	220	/*
	221	* if this is a modify event we may need to clear the ignored masks
	222	* otherwise return if neither the inode nor the vfsmount care about
	223	* this type of event.
	224	*/
	225	if (!(mask & FS_MODIFY) &&
	226	!(test_mask & to_tell->i_fsnotify_mask) &&
	227	!(mnt && test_mask & mnt->mnt_fsnotify_mask))
	228	return 0;
3a9fb89f	229
75c1be48	230	idx = srcu_read_lock(&fsnotify_mark_srcu);
7131485a	231
613a807f EP	232	if ((mask & FS_MODIFY) \|\|
613a807f EP	233	(test_mask & to_tell->i_fsnotify_mask))
ce8f76fb EP	234	inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
ce8f76fb EP	235	&fsnotify_mark_srcu);
613a807f	236
84e1ab4d EP	237	if (mnt && ((mask & FS_MODIFY) \|\|
	238	(test_mask & mnt->mnt_fsnotify_mask))) {
	239	vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first,
	240	&fsnotify_mark_srcu);
	241	inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
	242	&fsnotify_mark_srcu);
90586523	243	}
75c1be48	244
8edc6e16 JK	245	/*
	246	* We need to merge inode & vfsmount mark lists so that inode mark
	247	* ignore masks are properly reflected for mount mark notifications.
	248	* That's why this traversal is so complicated...
	249	*/
613a807f	250	while (inode_node \|\| vfsmount_node) {
8edc6e16 JK	251	inode_group = NULL;
	252	inode_mark = NULL;
	253	vfsmount_group = NULL;
	254	vfsmount_mark = NULL;
5f3f259f	255
613a807f EP	256	if (inode_node) {
613a807f EP	257	inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
0809ab69	258	struct fsnotify_mark, obj_list);
613a807f	259	inode_group = inode_mark->group;
f72adfd5	260	}
613a807f EP	261
	262	if (vfsmount_node) {
	263	vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
0809ab69	264	struct fsnotify_mark, obj_list);
613a807f	265	vfsmount_group = vfsmount_mark->group;
f72adfd5	266	}
613a807f	267
8edc6e16 JK	268	if (inode_group && vfsmount_group) {
	269	int cmp = fsnotify_compare_groups(inode_group,
	270	vfsmount_group);
	271	if (cmp > 0) {
	272	inode_group = NULL;
	273	inode_mark = NULL;
	274	} else if (cmp < 0) {
	275	vfsmount_group = NULL;
	276	vfsmount_mark = NULL;
	277	}
7131485a	278	}
8edc6e16 JK	279	ret = send_to_group(to_tell, inode_mark, vfsmount_mark, mask,
8edc6e16 JK	280	data, data_is, cookie, file_name);
613a807f	281
ff8bcbd0 EP	282	if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
	283	goto out;
	284
92b4678e	285	if (inode_group)
ce8f76fb EP	286	inode_node = srcu_dereference(inode_node->next,
ce8f76fb EP	287	&fsnotify_mark_srcu);
92b4678e	288	if (vfsmount_group)
ce8f76fb EP	289	vfsmount_node = srcu_dereference(vfsmount_node->next,
ce8f76fb EP	290	&fsnotify_mark_srcu);
7131485a	291	}
ff8bcbd0 EP	292	ret = 0;
ff8bcbd0 EP	293	out:
75c1be48	294	srcu_read_unlock(&fsnotify_mark_srcu, idx);
c4ec54b4	295
98b5c10d	296	return ret;
90586523 EP	297	}
	298	EXPORT_SYMBOL_GPL(fsnotify);
	299
	300	static __init int fsnotify_init(void)
	301	{
75c1be48 EP	302	int ret;
75c1be48 EP	303
20dee624 EP	304	BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
20dee624 EP	305
75c1be48 EP	306	ret = init_srcu_struct(&fsnotify_mark_srcu);
	307	if (ret)
	308	panic("initializing fsnotify_mark_srcu");
	309
	310	return 0;
90586523	311	}
75c1be48	312	core_initcall(fsnotify_init);