309 lines
9.4 KiB
Groff
309 lines
9.4 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 May 15, 2011
|
|
.Dt NFSV4 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm NFSv4
|
|
.Nd NFS Version 4 Protocol
|
|
.Sh DESCRIPTION
|
|
The NFS client and server provides support for the
|
|
.Tn NFSv4
|
|
specification; see
|
|
.%T "Network File System (NFS) Version 4 Protocol RFC 3530" .
|
|
The protocol is somewhat similar to NFS Version 3, but differs in significant
|
|
ways.
|
|
It uses a single compound RPC that concatenates operations to-gether.
|
|
Each of these operations are similar to the RPCs of NFS Version 3.
|
|
The operations in the compound are performed in order, until one of
|
|
them fails (returns an error) and then the RPC terminates at that point.
|
|
.Pp
|
|
It has
|
|
integrated locking support, which implies that the server is no longer
|
|
stateless.
|
|
As such, the
|
|
.Nm
|
|
server remains in recovery mode for a grace period (always greater than the
|
|
lease duration the server uses) after a reboot.
|
|
During this grace period, clients may recover state but not perform other
|
|
open/lock state changing operations.
|
|
To provide for correct recovery semantics, a small file described by
|
|
.Xr stablerestart 5
|
|
is used by the server during the recovery phase.
|
|
If this file is missing or empty, there is a backup copy maintained by
|
|
.Xr nfsd 8
|
|
that will be used. If either file is missing, they will be
|
|
created by the
|
|
.Xr nfsd 8 .
|
|
If both the file and the backup copy are empty,
|
|
it will result in the server starting without providing a grace period
|
|
for recovery.
|
|
Note that recovery only occurs when the server
|
|
machine is rebooted, not when the
|
|
.Xr nfsd 8
|
|
are just restarted.
|
|
.Pp
|
|
It provides several optional features not present in NFS Version 3:
|
|
.sp
|
|
.Bd -literal -offset indent -compact
|
|
- NFS Version 4 ACLs
|
|
- Referrals, which redirect subtrees to other servers
|
|
(not yet implemented)
|
|
- Delegations, which allow a client to operate on a file locally
|
|
.Ed
|
|
.Pp
|
|
The
|
|
.Nm
|
|
protocol does not use a separate mount protocol and assumes that the
|
|
server provides a single file system tree structure, rooted at the point
|
|
in the local file system tree specified by one or more
|
|
.sp 1
|
|
.Bd -literal -offset indent -compact
|
|
V4: <rootdir> [-sec=secflavors] [host(s) or net]
|
|
.Ed
|
|
.sp 1
|
|
line(s) in the
|
|
.Xr exports 5
|
|
file.
|
|
(See
|
|
.Xr exports 5
|
|
for details.)
|
|
The
|
|
.Xr nfsd 8
|
|
allows a limited subset of operations to be performed on non-exported subtrees
|
|
of the local file system, so that traversal of the tree to the exported
|
|
subtrees is possible.
|
|
As such, the ``<rootdir>'' can be in a non-exported file system.
|
|
However,
|
|
the entire tree that is rooted at that point must be in local file systems
|
|
that are of types that can be NFS exported.
|
|
Since the
|
|
.Nm
|
|
file system is rooted at ``<rootdir>'', setting this to anything other
|
|
than ``/'' will result in clients being required to use different mount
|
|
paths for
|
|
.Nm
|
|
than for NFS Version 2 or 3.
|
|
Unlike NFS Version 2 and 3, Version 4 allows a client mount to span across
|
|
multiple server file systems, although not all clients are capable of doing
|
|
this.
|
|
.Pp
|
|
.Nm
|
|
uses names for users and groups instead of numbers.
|
|
On the wire, they
|
|
take the form:
|
|
.sp
|
|
.Bd -literal -offset indent -compact
|
|
<user>@<dns.domain>
|
|
.Ed
|
|
.sp
|
|
where ``<dns.domain>'' is not the same as the DNS domain used
|
|
for host name lookups, but is usually set to the same string.
|
|
Most systems set this ``<dns.domain>''
|
|
to the domain name part of the machine's
|
|
.Xr hostname 1
|
|
by default.
|
|
However, this can normally be overridden by a command line
|
|
option or configuration file for the daemon used to do the name<->number
|
|
mapping.
|
|
Under FreeBSD, the mapping daemon is called
|
|
.Xr nfsuserd 8
|
|
and has a command line option that overrides the domain component of the
|
|
machine's hostname.
|
|
For use of
|
|
.Nm ,
|
|
either client or server, this daemon must be running.
|
|
If this ``<dns.domain>'' is not set correctly or the daemon is not running, ``ls -l'' will typically
|
|
report a lot of ``nobody'' and ``nogroup'' ownerships.
|
|
.Pp
|
|
Although uid/gid numbers are no longer used in the
|
|
.Nm
|
|
protocol, they will still be in the RPC authentication fields when
|
|
using AUTH_SYS (sec=sys), which is the default.
|
|
As such, in this case both the user/group name and number spaces must
|
|
be consistent between the client and server.
|
|
.Pp
|
|
However, if you run
|
|
.Nm
|
|
with RPCSEC_GSS (sec=krb5, krb5i, krb5p), only names and KerberosV tickets
|
|
will go on the wire.
|
|
.Sh SERVER SETUP
|
|
To set up the NFS server that supports
|
|
.Nm ,
|
|
you will need to either set the variables in
|
|
.Xr rc.conf 5
|
|
as follows:
|
|
.sp
|
|
.Bd -literal -offset indent -compact
|
|
nfs_server_enable="YES"
|
|
nfsv4_server_enable="YES"
|
|
nfsuserd_enable="YES"
|
|
.Ed
|
|
.sp
|
|
or start
|
|
.Xr mountd 8
|
|
and
|
|
.Xr nfsd 8
|
|
without the ``-o'' option, which would force use of the old server.
|
|
The
|
|
.Xr nfsuserd 8
|
|
daemon must also be running.
|
|
.Pp
|
|
You will also need to add at least one ``V4:'' line to the
|
|
.Xr exports 5
|
|
file for
|
|
.Nm
|
|
to work.
|
|
.Pp
|
|
If the file systems you are exporting are only being accessed via
|
|
.Nm
|
|
there are a couple of
|
|
.Xr sysctl 8
|
|
variables that you can change, which might improve performance.
|
|
.Bl -tag -width Ds
|
|
.It Cm vfs.nfsd.issue_delegations
|
|
when set non-zero, allows the server to issue Open Delegations to
|
|
clients.
|
|
These delegations permit the client to manipulate the file
|
|
locally on the client.
|
|
Unfortunately, at this time, client use of
|
|
delegations is limited, so performance gains may not be observed.
|
|
This can only be enabled when the file systems being exported to
|
|
.Nm
|
|
clients are not being accessed locally on the server and, if being
|
|
accessed via NFS Version 2 or 3 clients, these clients cannot be
|
|
using the NLM.
|
|
.It Cm vfs.nfsd.enable_locallocks
|
|
can be set to 0 to disable acquisition of local byte range locks.
|
|
Disabling local locking can only be done if neither local accesses
|
|
to the exported file systems nor the NLM is operating on them.
|
|
.El
|
|
.sp
|
|
Note that Samba server access would be considered ``local access'' for the above
|
|
discussion.
|
|
.Pp
|
|
To build a kernel with the NFS server that supports
|
|
.Nm
|
|
linked into it, the
|
|
.sp
|
|
.Bd -literal -offset indent -compact
|
|
options NFSD
|
|
.Ed
|
|
.sp
|
|
must be specified in the kernel's
|
|
.Xr config 5
|
|
file.
|
|
.Sh CLIENT MOUNTS
|
|
To do an
|
|
.Nm
|
|
mount, specify the ``nfsv4'' option on the
|
|
.Xr mount_nfs 8
|
|
command line.
|
|
This will force use of the client that supports
|
|
.Nm
|
|
plus set ``tcp'' and
|
|
.Nm .
|
|
.Pp
|
|
The
|
|
.Xr nfsuserd 8
|
|
must be running, as above.
|
|
If the
|
|
.Nm
|
|
server that is being mounted on supports delegations, you can start the
|
|
.Xr nfscbd 8
|
|
daemon to handle client side callbacks.
|
|
This will occur if
|
|
.sp
|
|
.Bd -literal -offset indent -compact
|
|
nfsuserd_enable="YES"
|
|
nfscbd_enable="YES"
|
|
.Ed
|
|
.sp
|
|
are set in
|
|
.Xr rc.conf 5 .
|
|
.sp
|
|
Without a functioning callback path, a server will never issue Delegations
|
|
to a client.
|
|
.sp
|
|
By default, the callback address will be set to the IP address acquired via
|
|
rtalloc() in the kernel and port# 7745.
|
|
To override the default port#, a command line option for
|
|
.Xr nfscbd 8
|
|
can be used.
|
|
.sp
|
|
To get callbacks to work when behind a NAT gateway, a port for the callback
|
|
service will need to be set up on the NAT gateway and then the address
|
|
of the NAT gateway (host IP plus port#) will need to be set by assigning the
|
|
.Xr sysctl 8
|
|
variable vfs.nfs.callback_addr to a string of the form:
|
|
.sp
|
|
N.N.N.N.N.N
|
|
.sp
|
|
where the first 4 Ns are the host IP address and the last two are the
|
|
port# in network byte order (all decimal #s in the range 0-255).
|
|
.Pp
|
|
To build a kernel with the client that supports
|
|
.Nm
|
|
linked into it, the option
|
|
.sp
|
|
.Bd -literal -offset indent -compact
|
|
options NFSCL
|
|
.Ed
|
|
.sp
|
|
must be specified in the kernel's
|
|
.Xr config 5
|
|
file.
|
|
.Pp
|
|
Options can be specified for the
|
|
.Xr nfsuserd 8
|
|
and
|
|
.Xr nfscbd 8
|
|
daemons at boot time via the ``nfsuserd_flags'' and ``nfscbd_flags''
|
|
.Xr rc.conf 5
|
|
variables.
|
|
.Sh FILES
|
|
.Bl -tag -width /var/db/nfs-stablerestart.bak -compact
|
|
.It Pa /var/db/nfs-stablerestart
|
|
NFS V4 stable restart file
|
|
.It Pa /var/db/nfs-stablerestart.bak
|
|
backup copy of the file
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr stablerestart 5 ,
|
|
.Xr mountd 8 ,
|
|
.Xr nfscbd 8 ,
|
|
.Xr nfsd 8 ,
|
|
.Xr nfsdumpstate 8 ,
|
|
.Xr nfsrevoke 8 ,
|
|
.Xr nfsuserd 8
|
|
.Sh BUGS
|
|
At this time, there is no recall of delegations for local file system
|
|
operations.
|
|
As such, delegations should only be enabled for file systems
|
|
that are being used solely as NFS export volumes and are not being accessed
|
|
via local system calls nor services such as Samba.
|