[mirror_ubuntu-bionic-kernel.git] / fs / notify / notification.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/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mount.h>
#include <linux/mutex.h>
#include <linux/namei.h>
#include <linux/path.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <asm/atomic.h>

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

static struct kmem_cache *fsnotify_event_cachep;

void fsnotify_get_event(struct fsnotify_event *event)
{
	atomic_inc(&event->refcnt);
}

void fsnotify_put_event(struct fsnotify_event *event)
{
	if (!event)
		return;

	if (atomic_dec_and_test(&event->refcnt)) {
		if (event->data_type == FSNOTIFY_EVENT_PATH)
			path_put(&event->path);

		kmem_cache_free(fsnotify_event_cachep, event);
	}
}

/*
 * Allocate a new event which will be sent to each group's handle_event function
 * if the group was interested in this particular event.
 */
struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
					     void *data, int data_type)
{
	struct fsnotify_event *event;

	event = kmem_cache_alloc(fsnotify_event_cachep, GFP_KERNEL);
	if (!event)
		return NULL;

	atomic_set(&event->refcnt, 1);

	spin_lock_init(&event->lock);

	event->path.dentry = NULL;
	event->path.mnt = NULL;
	event->inode = NULL;

	event->to_tell = to_tell;

	switch (data_type) {
	case FSNOTIFY_EVENT_FILE: {
		struct file *file = data;
		struct path *path = &file->f_path;
		event->path.dentry = path->dentry;
		event->path.mnt = path->mnt;
		path_get(&event->path);
		event->data_type = FSNOTIFY_EVENT_PATH;
		break;
	}
	case FSNOTIFY_EVENT_PATH: {
		struct path *path = data;
		event->path.dentry = path->dentry;
		event->path.mnt = path->mnt;
		path_get(&event->path);
		event->data_type = FSNOTIFY_EVENT_PATH;
		break;
	}
	case FSNOTIFY_EVENT_INODE:
		event->inode = data;
		event->data_type = FSNOTIFY_EVENT_INODE;
		break;
	case FSNOTIFY_EVENT_NONE:
		event->inode = NULL;
		event->path.dentry = NULL;
		event->path.mnt = NULL;
		break;
	default:
		BUG();
	}

	event->mask = mask;

	return event;
}

__init int fsnotify_notification_init(void)
{
	fsnotify_event_cachep = KMEM_CACHE(fsnotify_event, SLAB_PANIC);

	return 0;
}
subsys_initcall(fsnotify_notification_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/fs.h>
	20	#include <linux/init.h>
	21	#include <linux/kernel.h>
	22	#include <linux/list.h>
	23	#include <linux/mount.h>
	24	#include <linux/mutex.h>
	25	#include <linux/namei.h>
	26	#include <linux/path.h>
	27	#include <linux/slab.h>
	28	#include <linux/spinlock.h>
	29
	30	#include <asm/atomic.h>
	31
	32	#include <linux/fsnotify_backend.h>
	33	#include "fsnotify.h"
	34
	35	static struct kmem_cache *fsnotify_event_cachep;
	36
	37	void fsnotify_get_event(struct fsnotify_event *event)
	38	{
	39	atomic_inc(&event->refcnt);
	40	}
	41
	42	void fsnotify_put_event(struct fsnotify_event *event)
	43	{
	44	if (!event)
	45	return;
	46
	47	if (atomic_dec_and_test(&event->refcnt)) {
	48	if (event->data_type == FSNOTIFY_EVENT_PATH)
	49	path_put(&event->path);
	50
	51	kmem_cache_free(fsnotify_event_cachep, event);
	52	}
	53	}
	54
	55	/*
	56	* Allocate a new event which will be sent to each group's handle_event function
	57	* if the group was interested in this particular event.
	58	*/
	59	struct fsnotify_event fsnotify_create_event(struct inode to_tell, __u32 mask,
	60	void *data, int data_type)
	61	{
	62	struct fsnotify_event *event;
	63
	64	event = kmem_cache_alloc(fsnotify_event_cachep, GFP_KERNEL);
65	if (!event)
66	return NULL;
67
68	atomic_set(&event->refcnt, 1);
69
70	spin_lock_init(&event->lock);
71
72	event->path.dentry = NULL;
73	event->path.mnt = NULL;
74	event->inode = NULL;
75
76	event->to_tell = to_tell;
77
78	switch (data_type) {
79	case FSNOTIFY_EVENT_FILE: {
80	struct file *file = data;
81	struct path *path = &file->f_path;
82	event->path.dentry = path->dentry;
83	event->path.mnt = path->mnt;
84	path_get(&event->path);
85	event->data_type = FSNOTIFY_EVENT_PATH;
86	break;
87	}
88	case FSNOTIFY_EVENT_PATH: {
89	struct path *path = data;
90	event->path.dentry = path->dentry;
91	event->path.mnt = path->mnt;
92	path_get(&event->path);
93	event->data_type = FSNOTIFY_EVENT_PATH;
94	break;
95	}
96	case FSNOTIFY_EVENT_INODE:
97	event->inode = data;
98	event->data_type = FSNOTIFY_EVENT_INODE;
99	break;
100	case FSNOTIFY_EVENT_NONE:
101	event->inode = NULL;
102	event->path.dentry = NULL;
103	event->path.mnt = NULL;
104	break;
105	default:
106	BUG();
107	}
108
109	event->mask = mask;
110
111	return event;
112	}
113
114	__init int fsnotify_notification_init(void)
115	{
116	fsnotify_event_cachep = KMEM_CACHE(fsnotify_event, SLAB_PANIC);
117
118	return 0;
119	}
120	subsys_initcall(fsnotify_notification_init);
121