fs/cachefiles/main.c

   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);