FS-Cache: Fix __fscache_uncache_all_inode_pages()'s outer loop
[linux-2.6.git] / fs / fscache / netfs.c
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;
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);