1 /* Network filesystem caching backend to use cache files on a premounted
2 * filesystem
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public Licence
9 * as published by the Free Software Foundation; either version
10 * 2 of the Licence, or (at your option) any later version.
11 */
12
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/sched.h>
16 #include <linux/completion.h>
17 #include <linux/slab.h>
18 #include <linux/fs.h>
19 #include <linux/file.h>
20 #include <linux/namei.h>
21 #include <linux/mount.h>
22 #include <linux/statfs.h>
23 #include <linux/sysctl.h>
24 #include <linux/miscdevice.h>
25 #include "internal.h"
26
27 unsigned cachefiles_debug;
28 module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
29 MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
30
31 MODULE_DESCRIPTION("Mounted-filesystem based cache");
32 MODULE_AUTHOR("Red Hat, Inc.");
33 MODULE_LICENSE("GPL");
34
35 struct kmem_cache *cachefiles_object_jar;
36
37 static struct miscdevice cachefiles_dev = {
38 .minor = MISC_DYNAMIC_MINOR,
39 .name = "cachefiles",
40 .fops = &cachefiles_daemon_fops,
41 };
42
cachefiles_object_init_once(void * _object)43 static void cachefiles_object_init_once(void *_object)
44 {
45 struct cachefiles_object *object = _object;
46
47 memset(object, 0, sizeof(*object));
48 spin_lock_init(&object->work_lock);
49 }
50
51 /*
52 * initialise the fs caching module
53 */
cachefiles_init(void)54 static int __init cachefiles_init(void)
55 {
56 int ret;
57
58 ret = misc_register(&cachefiles_dev);
59 if (ret < 0)
60 goto error_dev;
61
62 /* create an object jar */
63 ret = -ENOMEM;
64 cachefiles_object_jar =
65 kmem_cache_create("cachefiles_object_jar",
66 sizeof(struct cachefiles_object),
67 0,
68 SLAB_HWCACHE_ALIGN,
69 cachefiles_object_init_once);
70 if (!cachefiles_object_jar) {
71 printk(KERN_NOTICE
72 "CacheFiles: Failed to allocate an object jar\n");
73 goto error_object_jar;
74 }
75
76 ret = cachefiles_proc_init();
77 if (ret < 0)
78 goto error_proc;
79
80 printk(KERN_INFO "CacheFiles: Loaded\n");
81 return 0;
82
83 error_proc:
84 kmem_cache_destroy(cachefiles_object_jar);
85 error_object_jar:
86 misc_deregister(&cachefiles_dev);
87 error_dev:
88 kerror("failed to register: %d", ret);
89 return ret;
90 }
91
92 fs_initcall(cachefiles_init);
93
94 /*
95 * clean up on module removal
96 */
cachefiles_exit(void)97 static void __exit cachefiles_exit(void)
98 {
99 printk(KERN_INFO "CacheFiles: Unloading\n");
100
101 cachefiles_proc_cleanup();
102 kmem_cache_destroy(cachefiles_object_jar);
103 misc_deregister(&cachefiles_dev);
104 }
105
106 module_exit(cachefiles_exit);
107