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/*
* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is included
* in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; If not, see
* http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
* GPL HEADER END
*/
/*
* Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
* Lustre is a trademark of Sun Microsystems, Inc.
*/
#define DEBUG_SUBSYSTEM S_FILTER
#include <linux/fs.h>
#include <linux/jbd.h>
#include <linux/module.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/libcfs/libcfs.h>
#include <lustre_fsfilt.h>
LIST_HEAD(fsfilt_types);
static struct fsfilt_operations *fsfilt_search_type(const char *type)
{
struct fsfilt_operations *found;
struct list_head *p;
list_for_each(p, &fsfilt_types) {
found = list_entry(p, struct fsfilt_operations, fs_list);
if (!strcmp(found->fs_type, type)) {
return found;
}
}
return NULL;
}
int fsfilt_register_ops(struct fsfilt_operations *fs_ops)
{
struct fsfilt_operations *found;
/* lock fsfilt_types list */
if ((found = fsfilt_search_type(fs_ops->fs_type))) {
if (found != fs_ops) {
CERROR("different operations for type %s\n",
fs_ops->fs_type);
/* unlock fsfilt_types list */
RETURN(-EEXIST);
}
} else {
try_module_get(THIS_MODULE);
list_add(&fs_ops->fs_list, &fsfilt_types);
}
/* unlock fsfilt_types list */
return 0;
}
EXPORT_SYMBOL(fsfilt_register_ops);
void fsfilt_unregister_ops(struct fsfilt_operations *fs_ops)
{
struct list_head *p;
/* lock fsfilt_types list */
list_for_each(p, &fsfilt_types) {
struct fsfilt_operations *found;
found = list_entry(p, typeof(*found), fs_list);
if (found == fs_ops) {
list_del(p);
module_put(THIS_MODULE);
break;
}
}
/* unlock fsfilt_types list */
}
EXPORT_SYMBOL(fsfilt_unregister_ops);
struct fsfilt_operations *fsfilt_get_ops(const char *type)
{
struct fsfilt_operations *fs_ops;
/* lock fsfilt_types list */
if (!(fs_ops = fsfilt_search_type(type))) {
char name[32];
int rc;
snprintf(name, sizeof(name) - 1, "fsfilt_%s", type);
name[sizeof(name) - 1] = '\0';
if (!(rc = request_module("%s", name))) {
fs_ops = fsfilt_search_type(type);
CDEBUG(D_INFO, "Loaded module '%s'\n", name);
if (!fs_ops)
rc = -ENOENT;
}
if (rc) {
CERROR("Can't find %s interface\n", name);
RETURN(ERR_PTR(rc < 0 ? rc : -rc));
/* unlock fsfilt_types list */
}
}
try_module_get(fs_ops->fs_owner);
/* unlock fsfilt_types list */
return fs_ops;
}
EXPORT_SYMBOL(fsfilt_get_ops);
void fsfilt_put_ops(struct fsfilt_operations *fs_ops)
{
module_put(fs_ops->fs_owner);
}
EXPORT_SYMBOL(fsfilt_put_ops);
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