| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 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 | #define CREATE_TRACE_POINTS |
| 26 | #include "internal.h" |
| 27 | |
| 28 | unsigned cachefiles_debug; |
| 29 | module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO); |
| 30 | MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask"); |
| 31 | |
| 32 | MODULE_DESCRIPTION("Mounted-filesystem based cache"); |
| 33 | MODULE_AUTHOR("Red Hat, Inc."); |
| 34 | MODULE_LICENSE("GPL"); |
| 35 | |
| 36 | struct kmem_cache *cachefiles_object_jar; |
| 37 | |
| 38 | static struct miscdevice cachefiles_dev = { |
| 39 | .minor = MISC_DYNAMIC_MINOR, |
| 40 | .name = "cachefiles", |
| 41 | .fops = &cachefiles_daemon_fops, |
| 42 | }; |
| 43 | |
| 44 | static void cachefiles_object_init_once(void *_object) |
| 45 | { |
| 46 | struct cachefiles_object *object = _object; |
| 47 | |
| 48 | memset(object, 0, sizeof(*object)); |
| 49 | spin_lock_init(&object->work_lock); |
| 50 | } |
| 51 | |
| 52 | /* |
| 53 | * initialise the fs caching module |
| 54 | */ |
| 55 | static int __init cachefiles_init(void) |
| 56 | { |
| 57 | int ret; |
| 58 | |
| 59 | ret = misc_register(&cachefiles_dev); |
| 60 | if (ret < 0) |
| 61 | goto error_dev; |
| 62 | |
| 63 | /* create an object jar */ |
| 64 | ret = -ENOMEM; |
| 65 | cachefiles_object_jar = |
| 66 | kmem_cache_create("cachefiles_object_jar", |
| 67 | sizeof(struct cachefiles_object), |
| 68 | 0, |
| 69 | SLAB_HWCACHE_ALIGN, |
| 70 | cachefiles_object_init_once); |
| 71 | if (!cachefiles_object_jar) { |
| 72 | pr_notice("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 | pr_info("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 | pr_err("failed to register: %d\n", ret); |
| 89 | return ret; |
| 90 | } |
| 91 | |
| 92 | fs_initcall(cachefiles_init); |
| 93 | |
| 94 | /* |
| 95 | * clean up on module removal |
| 96 | */ |
| 97 | static void __exit cachefiles_exit(void) |
| 98 | { |
| 99 | pr_info("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); |