NetBSD/sys/kern/vfs_hooks.c

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Apply the NFS exports list rototill patch: - Remove all NFS related stuff from file system specific code. - Drop the vfs_checkexp hook and generalize it in the new nfs_check_export function, thus removing redundancy from all file systems. - Move all NFS export-related stuff from kern/vfs_subr.c to the new file sys/nfs/nfs_export.c. The former was becoming large and its code is always compiled, regardless of the build options. Using the latter, the code is only compiled in when NFSSERVER is enabled. While doing this, also make some functions in nfs_subs.c conditional to NFSSERVER. - Add a new command in nfssvc(2), called NFSSVC_SETEXPORTSLIST, that takes a path and a set of export entries. At the moment it can only clear the exports list or append entries, one by one, but it is done in a way that allows setting the whole set of entries atomically in the future (see the comment in mountd_set_exports_list or in doc/TODO). - Change mountd(8) to use the nfssvc(2) system call instead of mount(2) so that it becomes file system agnostic. In fact, all this whole thing was done to remove a 'XXX' block from this utility! - Change the mount*, newfs and fsck* userland utilities to not deal with NFS exports initialization; done internally by the kernel when initializing the NFS support for each file system. - Implement an interface for VFS (called VFS hooks) so that several kernel subsystems can run arbitrary code upon receipt of specific VFS events. At the moment, this only provides support for unmount and is used to destroy NFS exports lists from the file systems being unmounted, though it has room for extension. Thanks go to yamt@, chs@, thorpej@, wrstuden@ and others for their comments and advice in the development of this patch.
2005-09-23 16:10:31 +04:00
/* $NetBSD: vfs_hooks.c,v 1.1 2005/09/23 12:10:33 jmmv Exp $ */
/*-
* Copyright (c) 2005 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Julio M. Merino Vidal.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* VFS hooks.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_hooks.c,v 1.1 2005/09/23 12:10:33 jmmv Exp $");
#include <sys/param.h>
#include <sys/mount.h>
/*
* Static list of file system specific hook sets supported by the kernel.
*/
__link_set_decl(vfs_hooks, struct vfs_hooks);
/*
* Initialize a VFS hook set that does nothing. This is to ensure that
* we have, at the very least, one item in the link set. Otherwise,
* ld(1) will complain.
*/
static struct vfs_hooks null_hooks = {
NULL /* vh_unmount */
};
VFS_HOOKS_ATTACH(null_hooks);
/*
* Macro to be used in one of the vfs_hooks_* function for hooks that
* return an error code. Calls will stop as soon as one of the hooks
* fails.
*/
#define VFS_HOOKS_W_ERROR(func, args) \
int error; \
struct vfs_hooks * const *hp; \
\
error = 0; \
\
__link_set_foreach(hp, vfs_hooks) { \
if ((*hp)-> func != NULL) { \
error = (*hp)-> func args; \
if (error != 0) \
break; \
} \
} \
\
return error;
/*
* Macro to be used in one of the vfs_hooks_* function for hooks that
* do not return any error code. All hooks will be executed
* unconditionally.
*/
#define VFS_HOOKS_WO_ERROR(func, fargs, hook, hargs) \
void \
func fargs \
{ \
struct vfs_hooks * const *hp; \
\
__link_set_foreach(hp, vfs_hooks) { \
if ((*hp)-> hook != NULL) \
(*hp)-> hook hargs; \
} \
}
/*
* Routines to iterate over VFS hooks lists and execute them.
*/
VFS_HOOKS_WO_ERROR(vfs_hooks_unmount, (struct mount *mp), vh_unmount, (mp));
/*
void
vfs_hooks_unmount(struct mount *mp)
{
VFS_HOOKS_WO_ERROR(vh_unmount, (mp));
}
*/