LXR linux/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
  28unsigned cachefiles_debug;
  29module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
  30MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
  31
  32MODULE_DESCRIPTION("Mounted-filesystem based cache");
  33MODULE_AUTHOR("Red Hat, Inc.");
  34MODULE_LICENSE("GPL");
  35
  36struct kmem_cache *cachefiles_object_jar;
  37
  38static struct miscdevice cachefiles_dev = {
  39        .minor  = MISC_DYNAMIC_MINOR,
  40        .name   = "cachefiles",
  41        .fops   = &cachefiles_daemon_fops,
  42};
  43
  44static 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 */
  55static 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
  83error_proc:
  84        kmem_cache_destroy(cachefiles_object_jar);
  85error_object_jar:
  86        misc_deregister(&cachefiles_dev);
  87error_dev:
  88        pr_err("failed to register: %d\n", ret);
  89        return ret;
  90}
  91
  92fs_initcall(cachefiles_init);
  93
  94/*
  95 * clean up on module removal
  96 */
  97static 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
 106module_exit(cachefiles_exit);
 107