xref: /kernel/linux/linux-5.10/fs/fscache/netfs.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-or-later
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)
6 */
7
8#define FSCACHE_DEBUG_LEVEL COOKIE
9#include <linux/module.h>
10#include <linux/slab.h>
11#include "internal.h"
12
13/*
14 * register a network filesystem for caching
15 */
16int __fscache_register_netfs(struct fscache_netfs *netfs)
17{
18	struct fscache_cookie *candidate, *cookie;
19
20	_enter("{%s}", netfs->name);
21
22	/* allocate a cookie for the primary index */
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) {
29		_leave(" = -ENOMEM");
30		return -ENOMEM;
31	}
32
33	candidate->flags = 1 << FSCACHE_COOKIE_ENABLED;
34
35	/* check the netfs type is not already present */
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);
42	}
43
44	fscache_cookie_get(cookie->parent, fscache_cookie_get_register_netfs);
45	atomic_inc(&cookie->parent->n_children);
46
47	netfs->primary_index = cookie;
48
49	pr_notice("Netfs '%s' registered for caching\n", netfs->name);
50	trace_fscache_netfs(netfs);
51	_leave(" = 0");
52	return 0;
53
54already_registered:
55	fscache_cookie_put(candidate, fscache_cookie_put_dup_netfs);
56	_leave(" = -EEXIST");
57	return -EEXIST;
58}
59EXPORT_SYMBOL(__fscache_register_netfs);
60
61/*
62 * unregister a network filesystem from the cache
63 * - all cookies must have been released first
64 */
65void __fscache_unregister_netfs(struct fscache_netfs *netfs)
66{
67	_enter("{%s.%u}", netfs->name, netfs->version);
68
69	fscache_relinquish_cookie(netfs->primary_index, NULL, false);
70	pr_notice("Netfs '%s' unregistered from caching\n", netfs->name);
71
72	_leave("");
73}
74EXPORT_SYMBOL(__fscache_unregister_netfs);
75