[net-next-2.6.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(&dcache_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 */
	list_for_each_entry(alias, &inode->i_dentry, 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) */
		list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
			if (!child->d_inode)
				continue;

			spin_lock(&child->d_lock);
			if (watched)
				child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
			else
				child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
			spin_unlock(&child->d_lock);
		}
	}
	spin_unlock(&dcache_lock);
}

/* Notify this dentry's parent about a child's events. */
void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
{
	struct dentry *parent;
	struct inode *p_inode;
	bool send = false;
	bool should_update_children = false;

	if (!dentry)
		dentry = file->f_path.dentry;

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

	spin_lock(&dentry->d_lock);
	parent = dentry->d_parent;
	p_inode = parent->d_inode;

	if (fsnotify_inode_watches_children(p_inode)) {
		if (p_inode->i_fsnotify_mask & mask) {
			dget(parent);
			send = true;
		}
	} else {
		/*
		 * The parent doesn't care about events on it's children but
		 * at least one child thought it did.  We need to run all the
		 * children and update their d_flags to let them know p_inode
		 * doesn't care about them any more.
		 */
		dget(parent);
		should_update_children = true;
	}

	spin_unlock(&dentry->d_lock);

	if (send) {
		/* 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;

		if (file)
			fsnotify(p_inode, mask, file, FSNOTIFY_EVENT_FILE,
				 dentry->d_name.name, 0);
		else
			fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
				 dentry->d_name.name, 0);
		dput(parent);
	}

	if (unlikely(should_update_children)) {
		__fsnotify_update_child_dentry_flags(p_inode);
		dput(parent);
	}
}
EXPORT_SYMBOL_GPL(__fsnotify_parent);

static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
			 struct fsnotify_mark *inode_mark,
			 struct fsnotify_mark *vfsmount_mark,
			 __u32 mask, void *data,
			 int data_is, u32 cookie,
			 const unsigned char *file_name,
			 struct fsnotify_event **event)
{
	struct fsnotify_group *group = inode_mark->group;
	__u32 inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
	__u32 vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);

	pr_debug("%s: group=%p to_tell=%p mnt=%p mark=%p mask=%x data=%p"
		 " data_is=%d cookie=%d event=%p\n", __func__, group, to_tell,
		 mnt, inode_mark, mask, data, data_is, cookie, *event);

	/* 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) {
		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 &= vfsmount_mark->mask;
		vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
		if (inode_mark)
			vfsmount_test_mask &= ~inode_mark->ignored_mask;
	}

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

	if (group->ops->should_send_event(group, to_tell, inode_mark,
					  vfsmount_mark, mask, data,
					  data_is) == false)
		return 0;

	if (!*event) {
		*event = fsnotify_create_event(to_tell, mask, data,
						data_is, file_name,
						cookie, GFP_KERNEL);
		if (!*event)
			return -ENOMEM;
	}
	return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event);
}

/*
 * 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, void *data, int data_is,
	     const unsigned char *file_name, u32 cookie)
{
	struct hlist_node *inode_node, *vfsmount_node;
	struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL;
	struct fsnotify_group *inode_group, *vfsmount_group;
	struct fsnotify_event *event = NULL;
	struct vfsmount *mnt;
	int idx, ret = 0;
	bool used_inode = false, used_vfsmount = false;
	/* 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_FILE)
		mnt = ((struct file *)data)->f_path.mnt;
	else
		mnt = NULL;

	/*
	 * 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);
	else
		inode_node = NULL;

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

	while (inode_node || vfsmount_node) {
		if (inode_node) {
			inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
						 struct fsnotify_mark, i.i_list);
			inode_group = inode_mark->group;
		} else
			inode_group = (void *)-1;

		if (vfsmount_node) {
			vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
							struct fsnotify_mark, m.m_list);
			vfsmount_group = vfsmount_mark->group;
		} else
			vfsmount_group = (void *)-1;

		if (inode_group < vfsmount_group) {
			/* handle inode */
			send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
				      data_is, cookie, file_name, &event);
			used_inode = true;
		} else if (vfsmount_group < inode_group) {
			send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data,
				      data_is, cookie, file_name, &event);
			used_vfsmount = true;
		} else {
			send_to_group(to_tell, mnt, inode_mark, vfsmount_mark,
				      mask, data, data_is, cookie, file_name,
				      &event);
			used_vfsmount = true;
			used_inode = true;
		}

		if (used_inode)
			inode_node = srcu_dereference(inode_node->next,
						      &fsnotify_mark_srcu);
		if (used_vfsmount)
			vfsmount_node = srcu_dereference(vfsmount_node->next,
							 &fsnotify_mark_srcu);
	}

	srcu_read_unlock(&fsnotify_mark_srcu, idx);
	/*
	 * fsnotify_create_event() took a reference so the event can't be cleaned
	 * up while we are still trying to add it to lists, drop that one.
	 */
	if (event)
		fsnotify_put_event(event);

	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
	62	spin_lock(&dcache_lock);
	63	/* run all of the dentries associated with this inode. Since this is a
	64	* directory, there damn well better only be one item on this list */
	65	list_for_each_entry(alias, &inode->i_dentry, d_alias) {
	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) */
	71	list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
	72	if (!child->d_inode)
	73	continue;
	74
	75	spin_lock(&child->d_lock);
	76	if (watched)
	77	child->d_flags \|= DCACHE_FSNOTIFY_PARENT_WATCHED;
	78	else
	79	child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
	80	spin_unlock(&child->d_lock);
	81	}
	82	}
	83	spin_unlock(&dcache_lock);
	84	}
	85
	86	/* Notify this dentry's parent about a child's events. */
3bcf3860	87	void __fsnotify_parent(struct file file, struct dentry dentry, __u32 mask)
c28f7e56 EP	88	{
	89	struct dentry *parent;
	90	struct inode *p_inode;
	91	bool send = false;
	92	bool should_update_children = false;
	93
72acc854	94	if (!dentry)
3bcf3860	95	dentry = file->f_path.dentry;
28c60e37	96
c28f7e56 EP	97	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
	98	return;
	99
	100	spin_lock(&dentry->d_lock);
	101	parent = dentry->d_parent;
	102	p_inode = parent->d_inode;
	103
	104	if (fsnotify_inode_watches_children(p_inode)) {
	105	if (p_inode->i_fsnotify_mask & mask) {
	106	dget(parent);
	107	send = true;
	108	}
	109	} else {
	110	/*
	111	* The parent doesn't care about events on it's children but
	112	* at least one child thought it did. We need to run all the
	113	* children and update their d_flags to let them know p_inode
	114	* doesn't care about them any more.
	115	*/
	116	dget(parent);
	117	should_update_children = true;
	118	}
	119
	120	spin_unlock(&dentry->d_lock);
	121
	122	if (send) {
	123	/* we are notifying a parent so come up with the new mask which
	124	* specifies these are events which came from a child. */
	125	mask \|= FS_EVENT_ON_CHILD;
	126
3bcf3860 EP	127	if (file)
3bcf3860 EP	128	fsnotify(p_inode, mask, file, FSNOTIFY_EVENT_FILE,
28c60e37 EP	129	dentry->d_name.name, 0);
	130	else
	131	fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
	132	dentry->d_name.name, 0);
c28f7e56 EP	133	dput(parent);
	134	}
	135
	136	if (unlikely(should_update_children)) {
	137	__fsnotify_update_child_dentry_flags(p_inode);
	138	dput(parent);
	139	}
	140	}
	141	EXPORT_SYMBOL_GPL(__fsnotify_parent);
	142
613a807f	143	static int send_to_group(struct inode to_tell, struct vfsmount mnt,
ce8f76fb EP	144	struct fsnotify_mark *inode_mark,
	145	struct fsnotify_mark *vfsmount_mark,
	146	__u32 mask, void *data,
613a807f	147	int data_is, u32 cookie,
3a9b16b4	148	const unsigned char *file_name,
c4ec54b4	149	struct fsnotify_event **event)
7131485a	150	{
ce8f76fb EP	151	struct fsnotify_group *group = inode_mark->group;
	152	__u32 inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
	153	__u32 vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
613a807f	154
3a9b16b4 EP	155	pr_debug("%s: group=%p to_tell=%p mnt=%p mark=%p mask=%x data=%p"
3a9b16b4 EP	156	" data_is=%d cookie=%d event=%p\n", __func__, group, to_tell,
ce8f76fb EP	157	mnt, inode_mark, mask, data, data_is, cookie, *event);
	158
	159	/* clear ignored on inode modification */
	160	if (mask & FS_MODIFY) {
	161	if (inode_mark &&
	162	!(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
	163	inode_mark->ignored_mask = 0;
	164	if (vfsmount_mark &&
	165	!(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
	166	vfsmount_mark->ignored_mask = 0;
	167	}
5ba08e2e	168
ce8f76fb EP	169	/* does the inode mark tell us to do something? */
	170	if (inode_mark) {
	171	inode_test_mask &= inode_mark->mask;
	172	inode_test_mask &= ~inode_mark->ignored_mask;
	173	}
613a807f	174
ce8f76fb EP	175	/* does the vfsmount_mark tell us to do something? */
	176	if (vfsmount_mark) {
	177	vfsmount_test_mask &= vfsmount_mark->mask;
	178	vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
	179	if (inode_mark)
	180	vfsmount_test_mask &= ~inode_mark->ignored_mask;
	181	}
	182
	183	if (!inode_test_mask && !vfsmount_test_mask)
613a807f EP	184	return 0;
613a807f EP	185
1968f5ee	186	if (group->ops->should_send_event(group, to_tell, inode_mark,
ce8f76fb EP	187	vfsmount_mark, mask, data,
ce8f76fb EP	188	data_is) == false)
c4ec54b4	189	return 0;
613a807f	190
7131485a EP	191	if (!*event) {
	192	*event = fsnotify_create_event(to_tell, mask, data,
	193	data_is, file_name,
	194	cookie, GFP_KERNEL);
7131485a	195	if (!*event)
c4ec54b4	196	return -ENOMEM;
7131485a	197	}
ce8f76fb	198	return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event);
7131485a EP	199	}
7131485a EP	200
90586523 EP	201	/*
	202	* This is the main call to fsnotify. The VFS calls into hook specific functions
	203	* in linux/fsnotify.h. Those functions then in turn call here. Here will call
	204	* out to all of the registered fsnotify_group. Those groups can then use the
	205	* notification event in whatever means they feel necessary.
	206	*/
c4ec54b4 EP	207	int fsnotify(struct inode to_tell, __u32 mask, void data, int data_is,
c4ec54b4 EP	208	const unsigned char *file_name, u32 cookie)
90586523	209	{
613a807f EP	210	struct hlist_node inode_node, vfsmount_node;
	211	struct fsnotify_mark inode_mark = NULL, vfsmount_mark = NULL;
	212	struct fsnotify_group inode_group, vfsmount_group;
90586523	213	struct fsnotify_event *event = NULL;
613a807f	214	struct vfsmount *mnt;
c4ec54b4	215	int idx, ret = 0;
613a807f	216	bool used_inode = false, used_vfsmount = false;
e42e2773 EP	217	/* global tests shouldn't care about events on child only the specific event */
e42e2773 EP	218	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
90586523	219
3bcf3860 EP	220	if (data_is == FSNOTIFY_EVENT_FILE)
3bcf3860 EP	221	mnt = ((struct file *)data)->f_path.mnt;
613a807f EP	222	else
	223	mnt = NULL;
	224
	225	/*
	226	* if this is a modify event we may need to clear the ignored masks
	227	* otherwise return if neither the inode nor the vfsmount care about
	228	* this type of event.
	229	*/
	230	if (!(mask & FS_MODIFY) &&
	231	!(test_mask & to_tell->i_fsnotify_mask) &&
	232	!(mnt && test_mask & mnt->mnt_fsnotify_mask))
	233	return 0;
3a9fb89f	234
75c1be48	235	idx = srcu_read_lock(&fsnotify_mark_srcu);
7131485a	236
613a807f EP	237	if ((mask & FS_MODIFY) \|\|
613a807f EP	238	(test_mask & to_tell->i_fsnotify_mask))
ce8f76fb EP	239	inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
ce8f76fb EP	240	&fsnotify_mark_srcu);
613a807f EP	241	else
	242	inode_node = NULL;
	243
	244	if (mnt) {
	245	if ((mask & FS_MODIFY) \|\|
	246	(test_mask & mnt->mnt_fsnotify_mask))
ce8f76fb EP	247	vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first,
ce8f76fb EP	248	&fsnotify_mark_srcu);
613a807f EP	249	else
	250	vfsmount_node = NULL;
	251	} else {
	252	mnt = NULL;
	253	vfsmount_node = NULL;
90586523	254	}
75c1be48	255
613a807f EP	256	while (inode_node \|\| vfsmount_node) {
	257	if (inode_node) {
	258	inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
	259	struct fsnotify_mark, i.i_list);
	260	inode_group = inode_mark->group;
	261	} else
	262	inode_group = (void *)-1;
	263
	264	if (vfsmount_node) {
	265	vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
	266	struct fsnotify_mark, m.m_list);
	267	vfsmount_group = vfsmount_mark->group;
	268	} else
	269	vfsmount_group = (void *)-1;
	270
	271	if (inode_group < vfsmount_group) {
	272	/* handle inode */
ce8f76fb	273	send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
613a807f EP	274	data_is, cookie, file_name, &event);
	275	used_inode = true;
	276	} else if (vfsmount_group < inode_group) {
ce8f76fb	277	send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data,
613a807f EP	278	data_is, cookie, file_name, &event);
	279	used_vfsmount = true;
	280	} else {
ce8f76fb EP	281	send_to_group(to_tell, mnt, inode_mark, vfsmount_mark,
	282	mask, data, data_is, cookie, file_name,
	283	&event);
613a807f	284	used_vfsmount = true;
613a807f	285	used_inode = true;
7131485a	286	}
613a807f EP	287
613a807f EP	288	if (used_inode)
ce8f76fb EP	289	inode_node = srcu_dereference(inode_node->next,
ce8f76fb EP	290	&fsnotify_mark_srcu);
613a807f	291	if (used_vfsmount)
ce8f76fb EP	292	vfsmount_node = srcu_dereference(vfsmount_node->next,
ce8f76fb EP	293	&fsnotify_mark_srcu);
7131485a	294	}
613a807f	295
75c1be48	296	srcu_read_unlock(&fsnotify_mark_srcu, idx);
90586523 EP	297	/*
	298	* fsnotify_create_event() took a reference so the event can't be cleaned
	299	* up while we are still trying to add it to lists, drop that one.
	300	*/
	301	if (event)
	302	fsnotify_put_event(event);
c4ec54b4	303
98b5c10d	304	return ret;
90586523 EP	305	}
	306	EXPORT_SYMBOL_GPL(fsnotify);
	307
	308	static __init int fsnotify_init(void)
	309	{
75c1be48 EP	310	int ret;
75c1be48 EP	311
20dee624 EP	312	BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
20dee624 EP	313
75c1be48 EP	314	ret = init_srcu_struct(&fsnotify_mark_srcu);
	315	if (ret)
	316	panic("initializing fsnotify_mark_srcu");
	317
	318	return 0;
90586523	319	}
75c1be48	320	core_initcall(fsnotify_init);