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