1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Network filesystem caching backend to use cache files on a premounted
3  * filesystem
4  *
5  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
6  * Written by David Howells (dhowells@redhat.com)
7  */
8 
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/sched.h>
12 #include <linux/completion.h>
13 #include <linux/slab.h>
14 #include <linux/fs.h>
15 #include <linux/file.h>
16 #include <linux/namei.h>
17 #include <linux/mount.h>
18 #include <linux/statfs.h>
19 #include <linux/sysctl.h>
20 #include <linux/miscdevice.h>
21 #define CREATE_TRACE_POINTS
22 #include "internal.h"
23 
24 unsigned cachefiles_debug;
25 module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
26 MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
27 
28 MODULE_DESCRIPTION("Mounted-filesystem based cache");
29 MODULE_AUTHOR("Red Hat, Inc.");
30 MODULE_LICENSE("GPL");
31 
32 struct kmem_cache *cachefiles_object_jar;
33 
34 static struct miscdevice cachefiles_dev = {
35 	.minor	= MISC_DYNAMIC_MINOR,
36 	.name	= "cachefiles",
37 	.fops	= &cachefiles_daemon_fops,
38 };
39 
cachefiles_object_init_once(void * _object)40 static void cachefiles_object_init_once(void *_object)
41 {
42 	struct cachefiles_object *object = _object;
43 
44 	memset(object, 0, sizeof(*object));
45 	spin_lock_init(&object->work_lock);
46 }
47 
48 /*
49  * initialise the fs caching module
50  */
cachefiles_init(void)51 static int __init cachefiles_init(void)
52 {
53 	int ret;
54 
55 	ret = misc_register(&cachefiles_dev);
56 	if (ret < 0)
57 		goto error_dev;
58 
59 	/* create an object jar */
60 	ret = -ENOMEM;
61 	cachefiles_object_jar =
62 		kmem_cache_create("cachefiles_object_jar",
63 				  sizeof(struct cachefiles_object),
64 				  0,
65 				  SLAB_HWCACHE_ALIGN,
66 				  cachefiles_object_init_once);
67 	if (!cachefiles_object_jar) {
68 		pr_notice("Failed to allocate an object jar\n");
69 		goto error_object_jar;
70 	}
71 
72 	ret = cachefiles_proc_init();
73 	if (ret < 0)
74 		goto error_proc;
75 
76 	pr_info("Loaded\n");
77 	return 0;
78 
79 error_proc:
80 	kmem_cache_destroy(cachefiles_object_jar);
81 error_object_jar:
82 	misc_deregister(&cachefiles_dev);
83 error_dev:
84 	pr_err("failed to register: %d\n", ret);
85 	return ret;
86 }
87 
88 fs_initcall(cachefiles_init);
89 
90 /*
91  * clean up on module removal
92  */
cachefiles_exit(void)93 static void __exit cachefiles_exit(void)
94 {
95 	pr_info("Unloading\n");
96 
97 	cachefiles_proc_cleanup();
98 	kmem_cache_destroy(cachefiles_object_jar);
99 	misc_deregister(&cachefiles_dev);
100 }
101 
102 module_exit(cachefiles_exit);
103