mount.8ufs

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)mount.8ufs	8.3	2/26/91
.TH mount 8ufs
.SH Name
mount \- mount the local ULTRIX File System (UFS)
.SH Syntax
.B "/etc/mount [ \-t ufs \-r ] ["
.I options
.B ]
.I device directory
.SH Description
.NXR "mount command"
.NXR "ufs_mount command"
.NXR "UFS" "mounting"
The
.MS mount 8ufs
command announces to the system that a file system
is present on the device
.I device.
The specified device must be a local device.
The file
.I directory
must exist and it must be a directory.
It becomes the name of the newly mounted file system.
.PP
.\" If invoked with \fB\-p\fP,
.\" .PN ufs_mount
.\" prints the list of mounted file systems reading standard input
.\" for \fIstruct fs_data\fP records output from the
.\" .I getmnt()
.\" system call.  This option is used by the mount(8) command.
.\" .PP
.PP
To further protect from system crashes,
only file systems that have
been cleanly checked by
.MS fsck 8
are mounted.
In emergency situations,
the superuser can override this requirement by using the
.PN force
option as shown below.
.PP
General users can mount file systems with certain restrictions
in addition to those listed in
.MS mount 8 .
The file system must have the clean byte set.
To ensure the clean byte is set,
run the
.MS fsck 8
command on the file system first.
You can also try the mount and if it fails,
then run
.PN fsck
and then try the mount again.
.PP
Note that the user must have execute permissions on the device.
.PP
A successful ufs-mount may generate the following warning message:
.EX
"Warning, device has exceeded xxx threshold, fsck(8) is advised"
.EE
where xxx is which metric was exceeded to cause the clean byte 
timeout factor to reach zero. See 
.MS fsck 8
for an explanation of the timeout algorithm.
.PP
Physically write-protected disks and magnetic tape file
systems must be mounted read only
or an error will occur at mount time.
.SH Options
See the 
.MS mount 8 
reference page for a description of the \fB\-t\fR option.
.IP "\fB\-o \fIoptions\fR" 12
Specifies 
.I options
as a sequence of comma-separated words from the list below.
.RS
.IP \fBforce\fR 14
The superuser can force the mounting of unclean file systems.
You should use the
.PN force
flag only in single-user mode when repairing
or recovering damaged file systems.
.IP \fBnodev\fR
Block and character special devices
cannot be accessed from this file system. If you are concerned with
nfs security, all ufs file systems that will be exported via nfs should
be ufs mounted with the 
.PN nodev 
option.
.IP \fBnoexec\fR
Binaries cannot be executed from this file system.
.IP \fBnosuid\fR
The
.PN setuid
and
.PN setgid
programs may not be executed from this file system. If you are concerned
with nfs security, all ufs file systems that will be exported via nfs
with the 
.PN \-r=0
option specified in the 
.PN /etc/exports
file should be
ufs mounted with the \fBnosuid\fR option.
.IP \fBpgthresh=##\fR
Set the paging threshold for this file system in kilobytes.
The default is 64 kilobytes.
.IP \fBsync\fR
All writes are immediately written to disk (synchronously)
as well as to the
buffer cache.
For the
.PN sync
option to be meaningful,
the file system must be mounted with write permissions.
.RE
.IP \-r 12
Mounts 
the \fIdevice\fP 
on \fIdirectory\fP read only.
.SH Restrictions
The
.PN /etc/ufs_mount
command should only be invoked by the
.PN mount
command.
Users (and superusers) should not invoke the
.PN ufs_mount
command.
.SH Examples
.\" The
.\" PN ufs_mount
.\" command is not the suggested interface.
The
.PN /etc/mount
command calls
.PN ufs_mount
to do its work and is the preferred interface.
A sample
.PN mount
command is:
.IP "" 5
# \fBmount \-t ufs \-o nodev,nosuid,noexec,pgthresh=100 /dev/ra0g /usr\fR
.\" .PP
.\" This would be translated to 
.\" .PN ufs_mount 
.\" as
.\" .EX
.\" ufs_mount \-o nodev,nosuid,noexec,pgthresh=100 /dev/ra0g /usr
.\" .EE
.\" .PP
.SH Files
.TP 20
.PN /etc/ufs_mount
UFS-specific mount program
.SH See Also
getmnt(2), mount(2), fsck(8), mount(8)