mirror of
https://github.com/torvalds/linux.git
synced 2024-11-05 11:32:04 +00:00
726dd7ff10
Add functions to register and unregister a network filesystem or other client of the FS-Cache service. This allocates and releases the cookie representing the top-level index for a netfs, and makes it available to the netfs. If the FS-Cache facility is disabled, then the calls are optimised away at compile time. Note that whilst this patch may appear to work with FS-Cache enabled and a netfs attempting to use it, it will leak the cookie it allocates for the netfs as fscache_relinquish_cookie() is implemented in a later patch. This will cause the slab code to emit a warning when the module is removed. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
104 lines
2.6 KiB
C
104 lines
2.6 KiB
C
/* 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\n",
|
|
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\n",
|
|
netfs->name);
|
|
|
|
_leave("");
|
|
}
|
|
EXPORT_SYMBOL(__fscache_unregister_netfs);
|