| /* |
| * 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/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 */ |
| found = fsfilt_search_type(fs_ops->fs_type); |
| if (found) { |
| 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 */ |
| fs_ops = fsfilt_search_type(type); |
| if (!fs_ops) { |
| char name[32]; |
| int rc; |
| |
| snprintf(name, sizeof(name) - 1, "fsfilt_%s", type); |
| name[sizeof(name) - 1] = '\0'; |
| |
| rc = request_module("%s", name); |
| if (!rc) { |
| 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); |