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

// SPDX-License-Identifier: GPL-2.0-or-later
/* FS-Cache netfs (client) registration
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

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

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

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

	/* allocate a cookie for the primary index */
	candidate = fscache_alloc_cookie(&fscache_fsdef_index,
					 &fscache_fsdef_netfs_def,
					 netfs->name, strlen(netfs->name),
					 &netfs->version, sizeof(netfs->version),
					 netfs, 0);
	if (!candidate) {
		_leave(" = -ENOMEM");
		return -ENOMEM;
	}

	candidate->flags = 1 << FSCACHE_COOKIE_ENABLED;

	/* check the netfs type is not already present */
	cookie = fscache_hash_cookie(candidate);
	if (!cookie)
		goto already_registered;
	if (cookie != candidate) {
		trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
		fscache_free_cookie(candidate);
	}

	fscache_cookie_get(cookie->parent, fscache_cookie_get_register_netfs);
	atomic_inc(&cookie->parent->n_children);

	netfs->primary_index = cookie;

	pr_notice("Netfs '%s' registered for caching\n", netfs->name);
	trace_fscache_netfs(netfs);
	_leave(" = 0");
	return 0;

already_registered:
	fscache_cookie_put(candidate, fscache_cookie_put_dup_netfs);
	_leave(" = -EEXIST");
	return -EEXIST;
}
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);

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

	_leave("");
}
EXPORT_SYMBOL(__fscache_unregister_netfs);
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
726dd7ff DH	2	/* FS-Cache netfs (client) registration
	3	*
	4	* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
726dd7ff DH	6	*/
	7
	8	#define FSCACHE_DEBUG_LEVEL COOKIE
	9	#include <linux/module.h>
	10	#include <linux/slab.h>
	11	#include "internal.h"
	12
726dd7ff DH	13	/*
	14	* register a network filesystem for caching
	15	*/
	16	int __fscache_register_netfs(struct fscache_netfs *netfs)
	17	{
ec0328e4	18	struct fscache_cookie candidate, cookie;
726dd7ff DH	19
	20	_enter("{%s}", netfs->name);
	21
726dd7ff	22	/* allocate a cookie for the primary index */
ec0328e4 DH	23	candidate = fscache_alloc_cookie(&fscache_fsdef_index,
	24	&fscache_fsdef_netfs_def,
	25	netfs->name, strlen(netfs->name),
	26	&netfs->version, sizeof(netfs->version),
	27	netfs, 0);
	28	if (!candidate) {
726dd7ff DH	29	_leave(" = -ENOMEM");
	30	return -ENOMEM;
	31	}
	32
ec0328e4	33	candidate->flags = 1 << FSCACHE_COOKIE_ENABLED;
726dd7ff DH	34
726dd7ff DH	35	/* check the netfs type is not already present */
ec0328e4 DH	36	cookie = fscache_hash_cookie(candidate);
	37	if (!cookie)
	38	goto already_registered;
	39	if (cookie != candidate) {
	40	trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
	41	fscache_free_cookie(candidate);
726dd7ff DH	42	}
726dd7ff DH	43
a18feb55	44	fscache_cookie_get(cookie->parent, fscache_cookie_get_register_netfs);
b130ed59	45	atomic_inc(&cookie->parent->n_children);
86108c2e	46
b130ed59	47	netfs->primary_index = cookie;
726dd7ff	48
36dfd116	49	pr_notice("Netfs '%s' registered for caching\n", netfs->name);
a18feb55	50	trace_fscache_netfs(netfs);
ec0328e4 DH	51	_leave(" = 0");
ec0328e4 DH	52	return 0;
726dd7ff DH	53
726dd7ff DH	54	already_registered:
ec0328e4 DH	55	fscache_cookie_put(candidate, fscache_cookie_put_dup_netfs);
	56	_leave(" = -EEXIST");
	57	return -EEXIST;
726dd7ff DH	58	}
	59	EXPORT_SYMBOL(__fscache_register_netfs);
	60
	61	/*
	62	* unregister a network filesystem from the cache
	63	* - all cookies must have been released first
	64	*/
	65	void __fscache_unregister_netfs(struct fscache_netfs *netfs)
	66	{
	67	_enter("{%s.%u}", netfs->name, netfs->version);
	68
402cb8dd	69	fscache_relinquish_cookie(netfs->primary_index, NULL, false);
ec0328e4	70	pr_notice("Netfs '%s' unregistered from caching\n", netfs->name);
726dd7ff DH	71
	72	_leave("");
	73	}
	74	EXPORT_SYMBOL(__fscache_unregister_netfs);