[people/ms/linux.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) {
		/* 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 (path)
			ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
				       dentry->d_name.name, 0);
		else
			ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
				       dentry->d_name.name, 0);
	}

	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 fsnotify_mark_connector *inode_conn, *vfsmount_conn;
	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 (!to_tell->i_fsnotify_marks &&
	    (!mnt || !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_conn = srcu_dereference(to_tell->i_fsnotify_marks,
					      &fsnotify_mark_srcu);
		if (inode_conn)
			inode_node = srcu_dereference(inode_conn->list.first,
						      &fsnotify_mark_srcu);
	}

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

extern struct kmem_cache *fsnotify_mark_connector_cachep;

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");

	fsnotify_mark_connector_cachep = KMEM_CACHE(fsnotify_mark_connector,
						    SLAB_PANIC);

	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) {
c28f7e56 EP	107	/* we are notifying a parent so come up with the new mask which
	108	* specifies these are events which came from a child. */
	109	mask \|= FS_EVENT_ON_CHILD;
	110
2069601b	111	if (path)
52420392 EP	112	ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
52420392 EP	113	dentry->d_name.name, 0);
28c60e37	114	else
52420392 EP	115	ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
52420392 EP	116	dentry->d_name.name, 0);
c28f7e56 EP	117	}
c28f7e56 EP	118
4d4eb366	119	dput(parent);
52420392 EP	120
52420392 EP	121	return ret;
c28f7e56 EP	122	}
	123	EXPORT_SYMBOL_GPL(__fsnotify_parent);
	124
fd657170	125	static int send_to_group(struct inode *to_tell,
ce8f76fb EP	126	struct fsnotify_mark *inode_mark,
ce8f76fb EP	127	struct fsnotify_mark *vfsmount_mark,
e637835e	128	__u32 mask, const void *data,
613a807f	129	int data_is, u32 cookie,
7053aee2	130	const unsigned char *file_name)
7131485a	131	{
faa9560a	132	struct fsnotify_group *group = NULL;
84e1ab4d EP	133	__u32 inode_test_mask = 0;
84e1ab4d EP	134	__u32 vfsmount_test_mask = 0;
613a807f	135
faa9560a EP	136	if (unlikely(!inode_mark && !vfsmount_mark)) {
	137	BUG();
	138	return 0;
	139	}
ce8f76fb EP	140
	141	/* clear ignored on inode modification */
	142	if (mask & FS_MODIFY) {
	143	if (inode_mark &&
	144	!(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
	145	inode_mark->ignored_mask = 0;
	146	if (vfsmount_mark &&
	147	!(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
	148	vfsmount_mark->ignored_mask = 0;
	149	}
5ba08e2e	150
ce8f76fb EP	151	/* does the inode mark tell us to do something? */
ce8f76fb EP	152	if (inode_mark) {
faa9560a	153	group = inode_mark->group;
84e1ab4d	154	inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
ce8f76fb EP	155	inode_test_mask &= inode_mark->mask;
	156	inode_test_mask &= ~inode_mark->ignored_mask;
	157	}
613a807f	158
ce8f76fb EP	159	/* does the vfsmount_mark tell us to do something? */
ce8f76fb EP	160	if (vfsmount_mark) {
84e1ab4d	161	vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
faa9560a	162	group = vfsmount_mark->group;
ce8f76fb EP	163	vfsmount_test_mask &= vfsmount_mark->mask;
	164	vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
	165	if (inode_mark)
	166	vfsmount_test_mask &= ~inode_mark->ignored_mask;
	167	}
	168
fd657170	169	pr_debug("%s: group=%p to_tell=%p mask=%x inode_mark=%p"
84e1ab4d	170	" inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x"
7053aee2	171	" data=%p data_is=%d cookie=%d\n",
fd657170	172	__func__, group, to_tell, mask, inode_mark,
84e1ab4d	173	inode_test_mask, vfsmount_mark, vfsmount_test_mask, data,
7053aee2	174	data_is, cookie);
faa9560a	175
ce8f76fb	176	if (!inode_test_mask && !vfsmount_test_mask)
613a807f EP	177	return 0;
613a807f EP	178
7053aee2 JK	179	return group->ops->handle_event(group, to_tell, inode_mark,
7053aee2 JK	180	vfsmount_mark, mask, data, data_is,
45a22f4c	181	file_name, cookie);
7131485a EP	182	}
7131485a EP	183
90586523 EP	184	/*
	185	* This is the main call to fsnotify. The VFS calls into hook specific functions
	186	* in linux/fsnotify.h. Those functions then in turn call here. Here will call
	187	* out to all of the registered fsnotify_group. Those groups can then use the
	188	* notification event in whatever means they feel necessary.
	189	*/
e637835e	190	int fsnotify(struct inode to_tell, __u32 mask, const void data, int data_is,
c4ec54b4	191	const unsigned char *file_name, u32 cookie)
90586523	192	{
84e1ab4d	193	struct hlist_node inode_node = NULL, vfsmount_node = NULL;
613a807f EP	194	struct fsnotify_mark inode_mark = NULL, vfsmount_mark = NULL;
613a807f EP	195	struct fsnotify_group inode_group, vfsmount_group;
9dd813c1	196	struct fsnotify_mark_connector inode_conn, vfsmount_conn;
c63181e6	197	struct mount *mnt;
c4ec54b4	198	int idx, ret = 0;
e42e2773 EP	199	/* global tests shouldn't care about events on child only the specific event */
e42e2773 EP	200	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
90586523	201
2069601b	202	if (data_is == FSNOTIFY_EVENT_PATH)
e637835e	203	mnt = real_mount(((const struct path *)data)->mnt);
613a807f EP	204	else
	205	mnt = NULL;
	206
7c49b861 DH	207	/*
	208	* Optimization: srcu_read_lock() has a memory barrier which can
	209	* be expensive. It protects walking the *_fsnotify_marks lists.
	210	* However, if we do not walk the lists, we do not have to do
	211	* SRCU because we have no references to any objects and do not
	212	* need SRCU to keep them "alive".
	213	*/
9dd813c1 JK	214	if (!to_tell->i_fsnotify_marks &&
9dd813c1 JK	215	(!mnt \|\| !mnt->mnt_fsnotify_marks))
7c49b861	216	return 0;
613a807f EP	217	/*
	218	* if this is a modify event we may need to clear the ignored masks
	219	* otherwise return if neither the inode nor the vfsmount care about
	220	* this type of event.
	221	*/
	222	if (!(mask & FS_MODIFY) &&
	223	!(test_mask & to_tell->i_fsnotify_mask) &&
	224	!(mnt && test_mask & mnt->mnt_fsnotify_mask))
	225	return 0;
3a9fb89f	226
75c1be48	227	idx = srcu_read_lock(&fsnotify_mark_srcu);
7131485a	228
613a807f	229	if ((mask & FS_MODIFY) \|\|
9dd813c1	230	(test_mask & to_tell->i_fsnotify_mask)) {
08991e83 JK	231	inode_conn = srcu_dereference(to_tell->i_fsnotify_marks,
08991e83 JK	232	&fsnotify_mark_srcu);
9dd813c1 JK	233	if (inode_conn)
	234	inode_node = srcu_dereference(inode_conn->list.first,
	235	&fsnotify_mark_srcu);
	236	}
613a807f	237
84e1ab4d EP	238	if (mnt && ((mask & FS_MODIFY) \|\|
84e1ab4d EP	239	(test_mask & mnt->mnt_fsnotify_mask))) {
08991e83 JK	240	inode_conn = srcu_dereference(to_tell->i_fsnotify_marks,
08991e83 JK	241	&fsnotify_mark_srcu);
9dd813c1 JK	242	if (inode_conn)
	243	inode_node = srcu_dereference(inode_conn->list.first,
	244	&fsnotify_mark_srcu);
08991e83 JK	245	vfsmount_conn = srcu_dereference(mnt->mnt_fsnotify_marks,
08991e83 JK	246	&fsnotify_mark_srcu);
9dd813c1 JK	247	if (vfsmount_conn)
	248	vfsmount_node = srcu_dereference(
	249	vfsmount_conn->list.first,
	250	&fsnotify_mark_srcu);
90586523	251	}
75c1be48	252
8edc6e16 JK	253	/*
	254	* We need to merge inode & vfsmount mark lists so that inode mark
	255	* ignore masks are properly reflected for mount mark notifications.
	256	* That's why this traversal is so complicated...
	257	*/
613a807f	258	while (inode_node \|\| vfsmount_node) {
8edc6e16 JK	259	inode_group = NULL;
	260	inode_mark = NULL;
	261	vfsmount_group = NULL;
	262	vfsmount_mark = NULL;
5f3f259f	263
613a807f EP	264	if (inode_node) {
613a807f EP	265	inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
0809ab69	266	struct fsnotify_mark, obj_list);
613a807f	267	inode_group = inode_mark->group;
f72adfd5	268	}
613a807f EP	269
	270	if (vfsmount_node) {
	271	vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
0809ab69	272	struct fsnotify_mark, obj_list);
613a807f	273	vfsmount_group = vfsmount_mark->group;
f72adfd5	274	}
613a807f	275
8edc6e16 JK	276	if (inode_group && vfsmount_group) {
	277	int cmp = fsnotify_compare_groups(inode_group,
	278	vfsmount_group);
	279	if (cmp > 0) {
	280	inode_group = NULL;
	281	inode_mark = NULL;
	282	} else if (cmp < 0) {
	283	vfsmount_group = NULL;
	284	vfsmount_mark = NULL;
	285	}
7131485a	286	}
8edc6e16 JK	287	ret = send_to_group(to_tell, inode_mark, vfsmount_mark, mask,
8edc6e16 JK	288	data, data_is, cookie, file_name);
613a807f	289
ff8bcbd0 EP	290	if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
	291	goto out;
	292
92b4678e	293	if (inode_group)
ce8f76fb EP	294	inode_node = srcu_dereference(inode_node->next,
ce8f76fb EP	295	&fsnotify_mark_srcu);
92b4678e	296	if (vfsmount_group)
ce8f76fb EP	297	vfsmount_node = srcu_dereference(vfsmount_node->next,
ce8f76fb EP	298	&fsnotify_mark_srcu);
7131485a	299	}
ff8bcbd0 EP	300	ret = 0;
ff8bcbd0 EP	301	out:
75c1be48	302	srcu_read_unlock(&fsnotify_mark_srcu, idx);
c4ec54b4	303
98b5c10d	304	return ret;
90586523 EP	305	}
	306	EXPORT_SYMBOL_GPL(fsnotify);
	307
9dd813c1 JK	308	extern struct kmem_cache *fsnotify_mark_connector_cachep;
9dd813c1 JK	309
90586523 EP	310	static __init int fsnotify_init(void)
90586523 EP	311	{
75c1be48 EP	312	int ret;
75c1be48 EP	313
20dee624 EP	314	BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
20dee624 EP	315
75c1be48 EP	316	ret = init_srcu_struct(&fsnotify_mark_srcu);
	317	if (ret)
	318	panic("initializing fsnotify_mark_srcu");
	319
9dd813c1 JK	320	fsnotify_mark_connector_cachep = KMEM_CACHE(fsnotify_mark_connector,
	321	SLAB_PANIC);
	322
75c1be48	323	return 0;
90586523	324	}
75c1be48	325	core_initcall(fsnotify_init);