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Commit 955d0091 authored by David Howells's avatar David Howells
Browse files

FS-Cache: Provide a slab for cookie allocation 



Provide a slab from which can be allocated the FS-Cache cookies that will be
presented to the netfs.

Also provide a slab constructor and a function to recursively discard a cookie
and its ancestor chain.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarSteve Dickson <steved@redhat.com>
Acked-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Tested-by: default avatarDaire Byrne <Daire.Byrne@framestore.com>
parent 4c515dd4

fs/fscache/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


fscache-y := \

	cache.o \

	cookie.o \

	fsdef.o \

	main.o

fs/fscache/cookie.c

0 → 100644
+56 −0
Original line number Diff line number Diff line 
/* netfs cookie management

 *

 * Copyright (C) 2004-2007 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 License

 * as published by the Free Software Foundation; either version

 * 2 of the License, or (at your option) any later version.

 */



#define FSCACHE_DEBUG_LEVEL COOKIE

#include <linux/module.h>

#include <linux/slab.h>

#include "internal.h"



struct kmem_cache *fscache_cookie_jar;



/*

 * initialise an cookie jar slab element prior to any use

 */

void fscache_cookie_init_once(void *_cookie)

{

	struct fscache_cookie *cookie = _cookie;



	memset(cookie, 0, sizeof(*cookie));

	spin_lock_init(&cookie->lock);

	INIT_HLIST_HEAD(&cookie->backing_objects);

}



/*

 * destroy a cookie

 */

void __fscache_cookie_put(struct fscache_cookie *cookie)

{

	struct fscache_cookie *parent;



	_enter("%p", cookie);



	for (;;) {

		_debug("FREE COOKIE %p", cookie);

		parent = cookie->parent;

		BUG_ON(!hlist_empty(&cookie->backing_objects));

		kmem_cache_free(fscache_cookie_jar, cookie);



		if (!parent)

			break;



		cookie = parent;

		BUG_ON(atomic_read(&cookie->usage) <= 0);

		if (!atomic_dec_and_test(&cookie->usage))

			break;

	}



	_leave("");

}

fs/fscache/internal.h

+8 −0
Original line number Diff line number Diff line
@@ -36,6 +36,14 @@ extern struct rw_semaphore fscache_addremove_sem; 
extern struct fscache_cache *fscache_select_cache_for_object(

	struct fscache_cookie *);



/*

 * fsc-cookie.c

 */

extern struct kmem_cache *fscache_cookie_jar;



extern void fscache_cookie_init_once(void *);

extern void __fscache_cookie_put(struct fscache_cookie *);



/*

 * fsc-fsdef.c

 */

fs/fscache/main.c

+15 −0
Original line number Diff line number Diff line
@@ -56,6 +56,18 @@ static int __init fscache_init(void) 
	if (ret < 0)

		goto error_proc;



	fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",

					       sizeof(struct fscache_cookie),

					       0,

					       0,

					       fscache_cookie_init_once);

	if (!fscache_cookie_jar) {

		printk(KERN_NOTICE

		       "FS-Cache: Failed to allocate a cookie jar\n");

		ret = -ENOMEM;

		goto error_cookie_jar;

	}



	fscache_root = kobject_create_and_add("fscache", kernel_kobj);

	if (!fscache_root)

		goto error_kobj;
@@ -64,6 +76,8 @@ static int __init fscache_init(void) 
	return 0;



error_kobj:

	kmem_cache_destroy(fscache_cookie_jar);

error_cookie_jar:

	fscache_proc_cleanup();

error_proc:

	slow_work_unregister_user();
@@ -81,6 +95,7 @@ static void __exit fscache_exit(void) 
	_enter("");



	kobject_put(fscache_root);

	kmem_cache_destroy(fscache_cookie_jar);

	fscache_proc_cleanup();

	slow_work_unregister_user();

	printk(KERN_NOTICE "FS-Cache: Unloaded\n");