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) 2021 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 #include <linux/netfs.h>
22 #include <trace/events/netfs.h>
23 #define CREATE_TRACE_POINTS
24 #include "internal.h"
25 
26 unsigned cachefiles_debug;
27 module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
28 MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
29 
30 MODULE_DESCRIPTION("Mounted-filesystem based cache");
31 MODULE_AUTHOR("Red Hat, Inc.");
32 MODULE_LICENSE("GPL");
33 
34 struct kmem_cache *cachefiles_object_jar;
35 
36 static struct miscdevice cachefiles_dev = {
37 	.minor	= MISC_DYNAMIC_MINOR,
38 	.name	= "cachefiles",
39 	.fops	= &cachefiles_daemon_fops,
40 };
41 
42 /*
43  * initialise the fs caching module
44  */
cachefiles_init(void)45 static int __init cachefiles_init(void)
46 {
47 	int ret;
48 
49 	ret = cachefiles_register_error_injection();
50 	if (ret < 0)
51 		goto error_einj;
52 	ret = misc_register(&cachefiles_dev);
53 	if (ret < 0)
54 		goto error_dev;
55 
56 	/* create an object jar */
57 	ret = -ENOMEM;
58 	cachefiles_object_jar =
59 		kmem_cache_create("cachefiles_object_jar",
60 				  sizeof(struct cachefiles_object),
61 				  0, SLAB_HWCACHE_ALIGN, NULL);
62 	if (!cachefiles_object_jar) {
63 		pr_notice("Failed to allocate an object jar\n");
64 		goto error_object_jar;
65 	}
66 
67 	pr_info("Loaded\n");
68 	return 0;
69 
70 error_object_jar:
71 	misc_deregister(&cachefiles_dev);
72 error_dev:
73 	cachefiles_unregister_error_injection();
74 error_einj:
75 	pr_err("failed to register: %d\n", ret);
76 	return ret;
77 }
78 
79 fs_initcall(cachefiles_init);
80 
81 /*
82  * clean up on module removal
83  */
cachefiles_exit(void)84 static void __exit cachefiles_exit(void)
85 {
86 	pr_info("Unloading\n");
87 
88 	kmem_cache_destroy(cachefiles_object_jar);
89 	misc_deregister(&cachefiles_dev);
90 	cachefiles_unregister_error_injection();
91 }
92 
93 module_exit(cachefiles_exit);
94