freebsd-skq/sbin/fsck_ffs/SMM.doc/1.t

.\" Copyright (c) 1982, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" 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 University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
.\"
.\"	$FreeBSD$
.\"	@(#)1.t	8.1 (Berkeley) 6/5/93
.\"
.ds RH Introduction
.NH
Introduction
.PP
This document reflects the use of
.I fsck_ffs
with the 4.2BSD and 4.3BSD file system organization.  This
is a revision of the
original paper written by
T. J. Kowalski.
.PP
When a UNIX
operating system is brought up, a consistency
check of the file systems should always be performed.
This precautionary measure helps to insure
a reliable environment for file storage on disk.
If an inconsistency is discovered,
corrective action must be taken.
.I Fsck_ffs
runs in two modes.
Normally it is run non-interactively by the system after 
a normal boot.
When running in this mode,
it will only make changes to the file system that are known
to always be correct.
If an unexpected inconsistency is found
.I fsck_ffs
will exit with a non-zero exit status, 
leaving the system running single-user.
Typically the operator then runs 
.I fsck_ffs
interactively.
When running in this mode,
each problem is listed followed by a suggested corrective action.
The operator must decide whether or not the suggested correction
should be made.
.PP
The purpose of this memo is to dispel the
mystique surrounding
file system inconsistencies.
It first describes the updating of the file system
(the calm before the storm) and
then describes file system corruption (the storm).
Finally,
the set of deterministic corrective actions
used by
.I fsck_ffs
(the Coast Guard
to the rescue) is presented.
.ds RH Overview of the File System
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.\" Copyright (c) 1982, 1993`
			`.\" The Regents of the University of California. All rights reserved.`
			`.\"`
			`.\" 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 University of`
			`.\" California, Berkeley and its contributors.`
			`.\" 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.`
			`.\"`
Reviewed by: rwatson, bp Approved by: rwatson Obtained from: NetBSD-current source tree The beginnings of the fsck wrappers stuff from NetBSD. This particular commit brings a newly repo-copied sbin/fsck_ffs/ (from sbin/fsck/) into fsck wrappers mode. A quick overview (the code reflects this): * Documentation changed to reflect fsck_ffs instead of fsck * Simply acts on a single filesystem, doesn't try to do any multiple filesystem magic - this is done by the fsck wrappers now And then specific to fsck_ffs: * link to /sbin/fsck_4.2bsd and /sbin/fsck_ufs. This is because right now the filesystem is of type ufs not ffs, and that during autodetection the labeltype rather than the VFS type is used - this is because when doing an autodetection of filesystem type in the fsck wrapper program, it does not have any link between label type (4.2bsd, vinum, etc) and VFS string. Note that this shouldn't break a build since the required buildworld Makefile magic and import of the fsck wrapper code into src/sbin/fsck/ will happen in a seperate commit. 2000-10-09 08:26:35 +00:00			`.\" $FreeBSD$`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.\" @(#)1.t 8.1 (Berkeley) 6/5/93`
			`.\"`
			`.ds RH Introduction`
			`.NH`
			`Introduction`
			`.PP`
			`This document reflects the use of`
Reviewed by: rwatson, bp Approved by: rwatson Obtained from: NetBSD-current source tree The beginnings of the fsck wrappers stuff from NetBSD. This particular commit brings a newly repo-copied sbin/fsck_ffs/ (from sbin/fsck/) into fsck wrappers mode. A quick overview (the code reflects this): * Documentation changed to reflect fsck_ffs instead of fsck * Simply acts on a single filesystem, doesn't try to do any multiple filesystem magic - this is done by the fsck wrappers now And then specific to fsck_ffs: * link to /sbin/fsck_4.2bsd and /sbin/fsck_ufs. This is because right now the filesystem is of type ufs not ffs, and that during autodetection the labeltype rather than the VFS type is used - this is because when doing an autodetection of filesystem type in the fsck wrapper program, it does not have any link between label type (4.2bsd, vinum, etc) and VFS string. Note that this shouldn't break a build since the required buildworld Makefile magic and import of the fsck wrapper code into src/sbin/fsck/ will happen in a seperate commit. 2000-10-09 08:26:35 +00:00			`.I fsck_ffs`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`with the 4.2BSD and 4.3BSD file system organization. This`
			`is a revision of the`
			`original paper written by`
			`T. J. Kowalski.`
			`.PP`
			`When a UNIX`
			`operating system is brought up, a consistency`
			`check of the file systems should always be performed.`
			`This precautionary measure helps to insure`
			`a reliable environment for file storage on disk.`
			`If an inconsistency is discovered,`
			`corrective action must be taken.`
Reviewed by: rwatson, bp Approved by: rwatson Obtained from: NetBSD-current source tree The beginnings of the fsck wrappers stuff from NetBSD. This particular commit brings a newly repo-copied sbin/fsck_ffs/ (from sbin/fsck/) into fsck wrappers mode. A quick overview (the code reflects this): * Documentation changed to reflect fsck_ffs instead of fsck * Simply acts on a single filesystem, doesn't try to do any multiple filesystem magic - this is done by the fsck wrappers now And then specific to fsck_ffs: * link to /sbin/fsck_4.2bsd and /sbin/fsck_ufs. This is because right now the filesystem is of type ufs not ffs, and that during autodetection the labeltype rather than the VFS type is used - this is because when doing an autodetection of filesystem type in the fsck wrapper program, it does not have any link between label type (4.2bsd, vinum, etc) and VFS string. Note that this shouldn't break a build since the required buildworld Makefile magic and import of the fsck wrapper code into src/sbin/fsck/ will happen in a seperate commit. 2000-10-09 08:26:35 +00:00			`.I Fsck_ffs`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`runs in two modes.`
			`Normally it is run non-interactively by the system after`
			`a normal boot.`
			`When running in this mode,`
			`it will only make changes to the file system that are known`
			`to always be correct.`
			`If an unexpected inconsistency is found`
Reviewed by: rwatson, bp Approved by: rwatson Obtained from: NetBSD-current source tree The beginnings of the fsck wrappers stuff from NetBSD. This particular commit brings a newly repo-copied sbin/fsck_ffs/ (from sbin/fsck/) into fsck wrappers mode. A quick overview (the code reflects this): * Documentation changed to reflect fsck_ffs instead of fsck * Simply acts on a single filesystem, doesn't try to do any multiple filesystem magic - this is done by the fsck wrappers now And then specific to fsck_ffs: * link to /sbin/fsck_4.2bsd and /sbin/fsck_ufs. This is because right now the filesystem is of type ufs not ffs, and that during autodetection the labeltype rather than the VFS type is used - this is because when doing an autodetection of filesystem type in the fsck wrapper program, it does not have any link between label type (4.2bsd, vinum, etc) and VFS string. Note that this shouldn't break a build since the required buildworld Makefile magic and import of the fsck wrapper code into src/sbin/fsck/ will happen in a seperate commit. 2000-10-09 08:26:35 +00:00			`.I fsck_ffs`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`will exit with a non-zero exit status,`
			`leaving the system running single-user.`
			`Typically the operator then runs`
Reviewed by: rwatson, bp Approved by: rwatson Obtained from: NetBSD-current source tree The beginnings of the fsck wrappers stuff from NetBSD. This particular commit brings a newly repo-copied sbin/fsck_ffs/ (from sbin/fsck/) into fsck wrappers mode. A quick overview (the code reflects this): * Documentation changed to reflect fsck_ffs instead of fsck * Simply acts on a single filesystem, doesn't try to do any multiple filesystem magic - this is done by the fsck wrappers now And then specific to fsck_ffs: * link to /sbin/fsck_4.2bsd and /sbin/fsck_ufs. This is because right now the filesystem is of type ufs not ffs, and that during autodetection the labeltype rather than the VFS type is used - this is because when doing an autodetection of filesystem type in the fsck wrapper program, it does not have any link between label type (4.2bsd, vinum, etc) and VFS string. Note that this shouldn't break a build since the required buildworld Makefile magic and import of the fsck wrapper code into src/sbin/fsck/ will happen in a seperate commit. 2000-10-09 08:26:35 +00:00			`.I fsck_ffs`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`interactively.`
			`When running in this mode,`
			`each problem is listed followed by a suggested corrective action.`
			`The operator must decide whether or not the suggested correction`
			`should be made.`
			`.PP`
			`The purpose of this memo is to dispel the`
			`mystique surrounding`
			`file system inconsistencies.`
			`It first describes the updating of the file system`
			`(the calm before the storm) and`
			`then describes file system corruption (the storm).`
			`Finally,`
			`the set of deterministic corrective actions`
			`used by`
Reviewed by: rwatson, bp Approved by: rwatson Obtained from: NetBSD-current source tree The beginnings of the fsck wrappers stuff from NetBSD. This particular commit brings a newly repo-copied sbin/fsck_ffs/ (from sbin/fsck/) into fsck wrappers mode. A quick overview (the code reflects this): * Documentation changed to reflect fsck_ffs instead of fsck * Simply acts on a single filesystem, doesn't try to do any multiple filesystem magic - this is done by the fsck wrappers now And then specific to fsck_ffs: * link to /sbin/fsck_4.2bsd and /sbin/fsck_ufs. This is because right now the filesystem is of type ufs not ffs, and that during autodetection the labeltype rather than the VFS type is used - this is because when doing an autodetection of filesystem type in the fsck wrapper program, it does not have any link between label type (4.2bsd, vinum, etc) and VFS string. Note that this shouldn't break a build since the required buildworld Makefile magic and import of the fsck wrapper code into src/sbin/fsck/ will happen in a seperate commit. 2000-10-09 08:26:35 +00:00			`.I fsck_ffs`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`(the Coast Guard`
			`to the rescue) is presented.`
			`.ds RH Overview of the File System`