common/os/vfs_conf.c

	vfs_conf.c revision a237e38e9161f0acd6451439d4a7dd597e66291d
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"
/* SunOS-4.1 1.16   */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/vfs.h>
#include <sys/t_lock.h>

extern int swapinit(int fstype, char *name);

/*
 * WARNING: THE POSITIONS OF FILESYSTEM TYPES IN THIS TABLE SHOULD NOT
 * BE CHANGED. These positions are used in generating fsids and
 * fhandles.  Thus, changing positions will cause a server to change
 * the fhandle it gives out for a file.  It is okay to reuse formerly
 * used slots, just be sure that we're not going to start supporting
 * the former owner of the slot again.
 *
 * Since there's been some question about whether the above comment is
 * true, let's provide more detail.  Most filesystems call
 * vfs_make_fsid with two arguments that go into making the fsid: the
 * dev number, and the fs type number - which is the offset of the
 * filesystem's entry in the below table.  If you would like to check
 * if the position of the filesystem in this table still affects the
 * fsid, just check what arguments filesystems are calling
 * vfs_make_fsid with.
 *
 * The scenario we're trying to prevent here is:
 *
 * NFS server gets upgraded to new kernel version with different vfssw
 * Clients are -not- rebooted, still retain filehandles
 * NFS server boots up and now the fsid of an exported fs is different
 *  --> Clients get stale file handle errors
 */

struct vfssw vfssw[] = {
    { "BADVFS" },               /* invalid */
    { "specfs" },               /* SPECFS */
    { "ufs" },              /* UFS */
    { "fifofs" },               /* FIFOFS */
    { "namefs" },               /* NAMEFS */
    { "proc" },             /* PROCFS */
    { "samfs" },                /* QFS */
    { "nfs" },              /* NFS Version 2 */
    { "zfs" },              /* ZFS */
    { "hsfs" },             /* HSFS */
    { "lofs" },             /* LOFS */
    { "tmpfs" },                /* TMPFS */
    { "fd" },               /* FDFS */
    { "pcfs" },             /* PCFS */
    { "swapfs", swapinit },         /* SWAPFS */
    { "mntfs" },                /* MNTFS */
    { "devfs" },                /* DEVFS */
    { "dev" },              /* DEV */
    { "ctfs" },             /* CONTRACTFS */
    { "objfs" },                /* OBJFS */
    { "sharefs" },              /* SHAREFS */
    { "" },                 /* reserved for loadable fs */
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
    { "" },
};

const int nfstype = (sizeof (vfssw) / sizeof (vfssw[0]));