94 lines
4.0 KiB
Groff
94 lines
4.0 KiB
Groff
.\" Copyright (c) 2009 Rick Macklem, University of Guelph
|
|
.\" 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd December 3, 2009
|
|
.Dt STABLERESTART 5
|
|
.Os
|
|
.Sh NAME
|
|
.Nm nfs-stablerestart
|
|
.Nd restart information for the
|
|
.Tn NFSv4
|
|
server
|
|
.Sh SYNOPSIS
|
|
.Nm nfs-stablerestart
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
file holds information that allows the
|
|
.Tn NFSv4
|
|
server to restart without always returning the NFSERR_NOGRACE error, as described in the
|
|
.Tn NFSv4
|
|
server specification; see
|
|
.%T "Network File System (NFS) Version 4 Protocol \\*(tNRFC\\*(sP 3530, Section 8.6.3" .
|
|
.Pp
|
|
The first record in the file, as defined by struct nfsf_rec in
|
|
/usr/include/fs/nfs/nfsrvstate.h, holds the lease duration of the
|
|
last incarnation of the server and the number of boot times that follows.
|
|
Following this are the number of previous boot times listed in the
|
|
first record.
|
|
The lease duration is used to set the grace period.
|
|
The boot times
|
|
are used to avoid the unlikely occurrence of a boot time being reused,
|
|
due to a TOD clock going backwards. This record and the previous boot times with this boot time added is re-written at the
|
|
end of the grace period.
|
|
.Pp
|
|
The rest of the file are appended records, as defined by
|
|
struct nfst_rec in /usr/include/fs/nfs/nfsrvstate.h and are used
|
|
represent one of two things. There are records which indicate that a
|
|
client successfully aquired state and records that indicate a client's state was revoked.
|
|
State revoke records indicate that state information
|
|
for a client was discarded, due to lease expiry and an otherwise
|
|
conflicting open or lock request being made by a different client.
|
|
These records can be used
|
|
to determine if clients might have done either of the
|
|
edge conditions.
|
|
.Pp
|
|
If a client might have done either edge condition or this file is
|
|
empty or corrupted, the server returns NFSERR_NOGRACE for any reclaim
|
|
request from the client.
|
|
.Pp
|
|
For correct operation of the server, it must be ensured that the file
|
|
is written to stable storage by the time a write op with IO_SYNC specified
|
|
has returned. This might require hardware level caching to be disabled for
|
|
a local disk drive that holds the file, or similar.
|
|
.Sh FILES
|
|
.Bl -tag -width /var/db/nfs-stablerestart -compact
|
|
.It Pa /var/db/nfs-stablerestart
|
|
NFSv4 stable restart file
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr nfsv4 4 ,
|
|
.Xr nfsd 8
|
|
.Sh BUGS
|
|
If the file is empty, the NFSv4 server has no choice but to return
|
|
NFSERR_NOGRACE for all reclaim requests. Although correct, this is
|
|
a highly undesirable occurrence, so the file should not be lost if
|
|
at all possible. Nfsd will not create the file if it does not
|
|
exist and will simply log a failure to start, in the hopes that the
|
|
file can be recovered from a backup. To move the file, you must edit
|
|
the nfsd sources and recompile it. This was done to discourage
|
|
accidental relocation of the file.
|