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fs/fscache/netfs.c
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FS-Cache: Add net...
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/* FS-Cache netfs (client) registration
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define FSCACHE_DEBUG_LEVEL COOKIE
#include <linux/module.h>
#include <linux/slab.h>
#include "internal.h"
static LIST_HEAD(fscache_netfs_list);
/*
* register a network filesystem for caching
*/
int __fscache_register_netfs(struct fscache_netfs *netfs)
{
struct fscache_netfs *ptr;
int ret;
_enter("{%s}", netfs->name);
INIT_LIST_HEAD(&netfs->link);
/* allocate a cookie for the primary index */
netfs->primary_index =
kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
if (!netfs->primary_index) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
/* initialise the primary index cookie */
atomic_set(&netfs->primary_index->usage, 1);
atomic_set(&netfs->primary_index->n_children, 0);
netfs->primary_index->def = &fscache_fsdef_netfs_def;
netfs->primary_index->parent = &fscache_fsdef_index;
netfs->primary_index->netfs_data = netfs;
atomic_inc(&netfs->primary_index->parent->usage);
atomic_inc(&netfs->primary_index->parent->n_children);
spin_lock_init(&netfs->primary_index->lock);
INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
/* check the netfs type is not already present */
down_write(&fscache_addremove_sem);
ret = -EEXIST;
list_for_each_entry(ptr, &fscache_netfs_list, link) {
if (strcmp(ptr->name, netfs->name) == 0)
goto already_registered;
}
list_add(&netfs->link, &fscache_netfs_list);
ret = 0;
printk(KERN_NOTICE "FS-Cache: Netfs '%s' registered for caching
",
netfs->name);
already_registered:
up_write(&fscache_addremove_sem);
if (ret < 0) {
netfs->primary_index->parent = NULL;
__fscache_cookie_put(netfs->primary_index);
netfs->primary_index = NULL;
}
_leave(" = %d", ret);
return ret;
}
EXPORT_SYMBOL(__fscache_register_netfs);
/*
* unregister a network filesystem from the cache
* - all cookies must have been released first
*/
void __fscache_unregister_netfs(struct fscache_netfs *netfs)
{
_enter("{%s.%u}", netfs->name, netfs->version);
down_write(&fscache_addremove_sem);
list_del(&netfs->link);
fscache_relinquish_cookie(netfs->primary_index, 0);
up_write(&fscache_addremove_sem);
printk(KERN_NOTICE "FS-Cache: Netfs '%s' unregistered from caching
",
netfs->name);
_leave("");
}
EXPORT_SYMBOL(__fscache_unregister_netfs);
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