// SPDX-License-Identifier: GPL-2.0-or-later
/* Network filesystem caching backend to use cache files on a premounted
 * filesystem
 *
 * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/statfs.h>
#include <linux/sysctl.h>
#include <linux/miscdevice.h>
#include <linux/netfs.h>
#include <trace/events/netfs.h>
#define CREATE_TRACE_POINTS
#include "internal.h"

unsigned cachefiles_debug;
module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");

MODULE_DESCRIPTION("Mounted-filesystem based cache");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");

struct kmem_cache *cachefiles_object_jar;

static struct miscdevice cachefiles_dev = {
        .minor  = MISC_DYNAMIC_MINOR,
        .name   = "cachefiles",
        .fops   = &cachefiles_daemon_fops,
};

/*
 * initialise the fs caching module
 */
static int __init cachefiles_init(void)
{
        int ret;

        ret = cachefiles_register_error_injection();
        if (ret < 0)
                goto error_einj;
        ret = misc_register(&cachefiles_dev);
        if (ret < 0)
                goto error_dev;

        /* create an object jar */
        ret = -ENOMEM;
        cachefiles_object_jar =
                kmem_cache_create("cachefiles_object_jar",
                                  sizeof(struct cachefiles_object),
                                  0, SLAB_HWCACHE_ALIGN, NULL);
        if (!cachefiles_object_jar) {
                pr_notice("Failed to allocate an object jar\n");
                goto error_object_jar;
        }

        pr_info("Loaded\n");
        return 0;

error_object_jar:
        misc_deregister(&cachefiles_dev);
error_dev:
        cachefiles_unregister_error_injection();
error_einj:
        pr_err("failed to register: %d\n", ret);
        return ret;
}

fs_initcall(cachefiles_init);

/*
 * clean up on module removal
 */
static void __exit cachefiles_exit(void)
{
        pr_info("Unloading\n");

        kmem_cache_destroy(cachefiles_object_jar);
        misc_deregister(&cachefiles_dev);
        cachefiles_unregister_error_injection();
}

module_exit(cachefiles_exit);