kernel/os/vfs_conf.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27 /* SunOS-4.1 1.16       */
  28
  29 #include <sys/types.h>
  30 #include <sys/param.h>
  31 #include <sys/vfs.h>
  32 #include <sys/t_lock.h>
  33
  34 extern int swapinit(int fstype, char *name);
  35
  36 /*
  37  * WARNING: THE POSITIONS OF FILESYSTEM TYPES IN THIS TABLE SHOULD NOT
  38  * BE CHANGED. These positions are used in generating fsids and
  39  * fhandles.  Thus, changing positions will cause a server to change
  40  * the fhandle it gives out for a file.  It is okay to reuse formerly
  41  * used slots, just be sure that we're not going to start supporting
  42  * the former owner of the slot again.
  43  *
  44  * Since there's been some question about whether the above comment is
  45  * true, let's provide more detail.  Most filesystems call
  46  * vfs_make_fsid with two arguments that go into making the fsid: the
  47  * dev number, and the fs type number - which is the offset of the
  48  * filesystem's entry in the below table.  If you would like to check
  49  * if the position of the filesystem in this table still affects the
  50  * fsid, just check what arguments filesystems are calling
  51  * vfs_make_fsid with.
  52  *
  53  * The scenario we're trying to prevent here is:
  54  *
  55  * NFS server gets upgraded to new kernel version with different vfssw
  56  * Clients are -not- rebooted, still retain filehandles
  57  * NFS server boots up and now the fsid of an exported fs is different
  58  *  --> Clients get stale file handle errors
  59  */
  60
  61 struct vfssw vfssw[] = {
  62         { "BADVFS" },                           /* invalid */
  63         { "specfs" },                           /* SPECFS */
  64         { "ufs" },                              /* UFS */
  65         { "fifofs" },                           /* FIFOFS */
  66         { "namefs" },                           /* NAMEFS */
  67         { "proc" },                             /* PROCFS */
  68         { "samfs" },                            /* QFS */
  69         { "nfs" },                              /* NFS Version 2 */
  70         { "zfs" },                              /* ZFS */
  71         { "hsfs" },                             /* HSFS */
  72         { "lofs" },                             /* LOFS */
  73         { "tmpfs" },                            /* TMPFS */
  74         { "fd" },                               /* FDFS */
  75         { "pcfs" },                             /* PCFS */
  76         { "swapfs", swapinit },                 /* SWAPFS */
  77         { "mntfs" },                            /* MNTFS */
  78         { "devfs" },                            /* DEVFS */
  79         { "dev" },                              /* DEV */
  80         { "ctfs" },                             /* CONTRACTFS */
  81         { "objfs" },                            /* OBJFS */
  82         { "sharefs" },                          /* SHAREFS */
  83         { "dcfs" },                             /* DCFS */
  84         { "smbfs" },                            /* SMBFS */
  85         { "" },                                 /* reserved for loadable fs */
  86         { "" },
  87         { "" },
  88         { "" },
  89         { "" },
  90         { "" },
  91         { "" },
  92         { "" },
  93         { "" },
  94         { "" },
  95         { "" },
  96         { "" },
  97         { "" },
  98 };
  99
 100 const int nfstype = (sizeof (vfssw) / sizeof (vfssw[0]));