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 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 */ 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 pr_info("Loaded\n"); 73 return 0; 74 75 error_object_jar: 76 misc_deregister(&cachefiles_dev); 77 error_dev: 78 pr_err("failed to register: %d\n", ret); 79 return ret; 80 } 81 82 fs_initcall(cachefiles_init); 83 84 /* 85 * clean up on module removal 86 */ 87 static void __exit cachefiles_exit(void) 88 { 89 pr_info("Unloading\n"); 90 91 kmem_cache_destroy(cachefiles_object_jar); 92 misc_deregister(&cachefiles_dev); 93 } 94 95 module_exit(cachefiles_exit); 96