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 */
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 */
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
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