[linux-2.6-block.git] / fs / fscache / netfs.c

/* FS-Cache netfs (client) registration
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#define FSCACHE_DEBUG_LEVEL COOKIE
#include <linux/module.h>
#include <linux/slab.h>
#include "internal.h"

static LIST_HEAD(fscache_netfs_list);

/*
 * register a network filesystem for caching
 */
int __fscache_register_netfs(struct fscache_netfs *netfs)
{
	struct fscache_netfs *ptr;
	struct fscache_cookie *cookie;
	int ret;

	_enter("{%s}", netfs->name);

	INIT_LIST_HEAD(&netfs->link);

	/* allocate a cookie for the primary index */
	cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);

	if (!cookie) {
		_leave(" = -ENOMEM");
		return -ENOMEM;
	}

	/* initialise the primary index cookie */
	atomic_set(&cookie->usage, 1);
	atomic_set(&cookie->n_children, 0);
	atomic_set(&cookie->n_active, 1);

	cookie->def		= &fscache_fsdef_netfs_def;
	cookie->parent		= &fscache_fsdef_index;
	cookie->netfs_data	= netfs;
	cookie->flags		= 1 << FSCACHE_COOKIE_ENABLED;

	spin_lock_init(&cookie->lock);
	INIT_HLIST_HEAD(&cookie->backing_objects);

	/* check the netfs type is not already present */
	down_write(&fscache_addremove_sem);

	ret = -EEXIST;
	list_for_each_entry(ptr, &fscache_netfs_list, link) {
		if (strcmp(ptr->name, netfs->name) == 0)
			goto already_registered;
	}

	atomic_inc(&cookie->parent->usage);
	atomic_inc(&cookie->parent->n_children);

	netfs->primary_index = cookie;
	list_add(&netfs->link, &fscache_netfs_list);
	ret = 0;

	pr_notice("Netfs '%s' registered for caching\n", netfs->name);

already_registered:
	up_write(&fscache_addremove_sem);

	if (ret < 0)
		kmem_cache_free(fscache_cookie_jar, cookie);

	_leave(" = %d", ret);
	return ret;
}
EXPORT_SYMBOL(__fscache_register_netfs);

/*
 * unregister a network filesystem from the cache
 * - all cookies must have been released first
 */
void __fscache_unregister_netfs(struct fscache_netfs *netfs)
{
	_enter("{%s.%u}", netfs->name, netfs->version);

	down_write(&fscache_addremove_sem);

	list_del(&netfs->link);
	fscache_relinquish_cookie(netfs->primary_index, 0);

	up_write(&fscache_addremove_sem);

	pr_notice("Netfs '%s' unregistered from caching\n",
		  netfs->name);

	_leave("");
}
EXPORT_SYMBOL(__fscache_unregister_netfs);
Commit	Line	Data
726dd7ff DH	1	/* FS-Cache netfs (client) registration
	2	*
	3	* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public Licence
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the Licence, or (at your option) any later version.
	10	*/
	11
	12	#define FSCACHE_DEBUG_LEVEL COOKIE
	13	#include <linux/module.h>
	14	#include <linux/slab.h>
	15	#include "internal.h"
	16
	17	static LIST_HEAD(fscache_netfs_list);
	18
	19	/*
	20	* register a network filesystem for caching
	21	*/
	22	int __fscache_register_netfs(struct fscache_netfs *netfs)
	23	{
	24	struct fscache_netfs *ptr;
b130ed59	25	struct fscache_cookie *cookie;
726dd7ff DH	26	int ret;
	27
	28	_enter("{%s}", netfs->name);
	29
	30	INIT_LIST_HEAD(&netfs->link);
	31
	32	/* allocate a cookie for the primary index */
b130ed59	33	cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
726dd7ff	34
b130ed59	35	if (!cookie) {
726dd7ff DH	36	_leave(" = -ENOMEM");
	37	return -ENOMEM;
	38	}
	39
	40	/* initialise the primary index cookie */
b130ed59 KM	41	atomic_set(&cookie->usage, 1);
	42	atomic_set(&cookie->n_children, 0);
	43	atomic_set(&cookie->n_active, 1);
726dd7ff	44
b130ed59 KM	45	cookie->def = &fscache_fsdef_netfs_def;
	46	cookie->parent = &fscache_fsdef_index;
	47	cookie->netfs_data = netfs;
	48	cookie->flags = 1 << FSCACHE_COOKIE_ENABLED;
726dd7ff	49
b130ed59 KM	50	spin_lock_init(&cookie->lock);
b130ed59 KM	51	INIT_HLIST_HEAD(&cookie->backing_objects);
726dd7ff DH	52
	53	/* check the netfs type is not already present */
	54	down_write(&fscache_addremove_sem);
	55
	56	ret = -EEXIST;
	57	list_for_each_entry(ptr, &fscache_netfs_list, link) {
	58	if (strcmp(ptr->name, netfs->name) == 0)
	59	goto already_registered;
	60	}
	61
b130ed59 KM	62	atomic_inc(&cookie->parent->usage);
b130ed59 KM	63	atomic_inc(&cookie->parent->n_children);
86108c2e	64
b130ed59	65	netfs->primary_index = cookie;
726dd7ff DH	66	list_add(&netfs->link, &fscache_netfs_list);
	67	ret = 0;
	68
36dfd116	69	pr_notice("Netfs '%s' registered for caching\n", netfs->name);
726dd7ff DH	70
	71	already_registered:
	72	up_write(&fscache_addremove_sem);
	73
b130ed59 KM	74	if (ret < 0)
b130ed59 KM	75	kmem_cache_free(fscache_cookie_jar, cookie);
726dd7ff DH	76
	77	_leave(" = %d", ret);
	78	return ret;
	79	}
	80	EXPORT_SYMBOL(__fscache_register_netfs);
	81
	82	/*
	83	* unregister a network filesystem from the cache
	84	* - all cookies must have been released first
	85	*/
	86	void __fscache_unregister_netfs(struct fscache_netfs *netfs)
	87	{
	88	_enter("{%s.%u}", netfs->name, netfs->version);
	89
	90	down_write(&fscache_addremove_sem);
	91
	92	list_del(&netfs->link);
	93	fscache_relinquish_cookie(netfs->primary_index, 0);
	94
	95	up_write(&fscache_addremove_sem);
	96
36dfd116 FF	97	pr_notice("Netfs '%s' unregistered from caching\n",
36dfd116 FF	98	netfs->name);
726dd7ff DH	99
	100	_leave("");
	101	}
	102	EXPORT_SYMBOL(__fscache_unregister_netfs);