fs/cachefiles/main.c

   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);