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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); |
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); |
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) |
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", |
98 | netfs->name); | |
726dd7ff DH |
99 | |
100 | _leave(""); | |
101 | } | |
102 | EXPORT_SYMBOL(__fscache_unregister_netfs); |