[linux.git] / fs / fscache / netfs.c

/* FS-Cache netfs (client) registration
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * 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;
	int ret;

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

	INIT_LIST_HEAD(&netfs->link);

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

	if (!netfs->primary_index) {
		_leave(" = -ENOMEM");
		return -ENOMEM;
	}

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

	netfs->primary_index->def		= &fscache_fsdef_netfs_def;
	netfs->primary_index->parent		= &fscache_fsdef_index;
	netfs->primary_index->netfs_data	= netfs;

	atomic_inc(&netfs->primary_index->parent->usage);
	atomic_inc(&netfs->primary_index->parent->n_children);

	spin_lock_init(&netfs->primary_index->lock);
	INIT_HLIST_HEAD(&netfs->primary_index->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;
	}

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

	printk(KERN_NOTICE "FS-Cache: Netfs '%s' registered for caching\n",
	       netfs->name);

already_registered:
	up_write(&fscache_addremove_sem);

	if (ret < 0) {
		netfs->primary_index->parent = NULL;
		__fscache_cookie_put(netfs->primary_index);
		netfs->primary_index = NULL;
	}

	_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);

	printk(KERN_NOTICE "FS-Cache: 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 ([email protected])
	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;
	25	int ret;
	26
	27	_enter("{%s}", netfs->name);
	28
	29	INIT_LIST_HEAD(&netfs->link);
	30
	31	/* allocate a cookie for the primary index */
	32	netfs->primary_index =
	33	kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
	34
	35	if (!netfs->primary_index) {
	36	_leave(" = -ENOMEM");
	37	return -ENOMEM;
	38	}
	39
	40	/* initialise the primary index cookie */
	41	atomic_set(&netfs->primary_index->usage, 1);
	42	atomic_set(&netfs->primary_index->n_children, 0);
	43
	44	netfs->primary_index->def = &fscache_fsdef_netfs_def;
	45	netfs->primary_index->parent = &fscache_fsdef_index;
	46	netfs->primary_index->netfs_data = netfs;
	47
	48	atomic_inc(&netfs->primary_index->parent->usage);
	49	atomic_inc(&netfs->primary_index->parent->n_children);
	50
	51	spin_lock_init(&netfs->primary_index->lock);
	52	INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
	53
	54	/* check the netfs type is not already present */
	55	down_write(&fscache_addremove_sem);
	56
	57	ret = -EEXIST;
	58	list_for_each_entry(ptr, &fscache_netfs_list, link) {
	59	if (strcmp(ptr->name, netfs->name) == 0)
	60	goto already_registered;
	61	}
	62
	63	list_add(&netfs->link, &fscache_netfs_list);
	64	ret = 0;
65
66	printk(KERN_NOTICE "FS-Cache: Netfs '%s' registered for caching\n",
67	netfs->name);
68
69	already_registered:
70	up_write(&fscache_addremove_sem);
71
72	if (ret < 0) {
73	netfs->primary_index->parent = NULL;
74	__fscache_cookie_put(netfs->primary_index);
75	netfs->primary_index = NULL;
76	}
77
78	_leave(" = %d", ret);
79	return ret;
80	}
81	EXPORT_SYMBOL(__fscache_register_netfs);
82
83	/*
84	* unregister a network filesystem from the cache
85	* - all cookies must have been released first
86	*/
87	void __fscache_unregister_netfs(struct fscache_netfs *netfs)
88	{
89	_enter("{%s.%u}", netfs->name, netfs->version);
90
91	down_write(&fscache_addremove_sem);
92
93	list_del(&netfs->link);
94	fscache_relinquish_cookie(netfs->primary_index, 0);
95
96	up_write(&fscache_addremove_sem);
97
98	printk(KERN_NOTICE "FS-Cache: Netfs '%s' unregistered from caching\n",
99	netfs->name);
100
101	_leave("");
102	}
103	EXPORT_SYMBOL(__fscache_unregister_netfs);