LXR linux/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
  26unsigned cachefiles_debug;
  27module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
  28MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
  29
  30MODULE_DESCRIPTION("Mounted-filesystem based cache");
  31MODULE_AUTHOR("Red Hat, Inc.");
  32MODULE_LICENSE("GPL");
  33
  34struct kmem_cache *cachefiles_object_jar;
  35
  36static 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 */
  45static 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
  70error_object_jar:
  71        misc_deregister(&cachefiles_dev);
  72error_dev:
  73        cachefiles_unregister_error_injection();
  74error_einj:
  75        pr_err("failed to register: %d\n", ret);
  76        return ret;
  77}
  78
  79fs_initcall(cachefiles_init);
  80
  81/*
  82 * clean up on module removal
  83 */
  84static 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
  93module_exit(cachefiles_exit);
  94