253 lines
6.6 KiB
Groff
253 lines
6.6 KiB
Groff
.\" Copyright (c) 2013 Marcel Moolenaar
|
|
.\" Copyright (c) 2013 Craig Rodrigues
|
|
.\" 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 AUTHORS 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 AUTHORS 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 October 17, 2013
|
|
.Dt MOUNT.CONF 5
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mount.conf
|
|
.Nd root file system mount configuration file
|
|
.Sh SYNOPSIS
|
|
.Pa /.mount.conf
|
|
.Sh DESCRIPTION
|
|
During the bootup process, the
|
|
.Fx
|
|
kernel will try to mount the root file system
|
|
using the logic in the
|
|
.Fn vfs_mountroot
|
|
function in
|
|
.Pa src/sys/kern/vfs_mountroot.c .
|
|
The root mount logic can be described as follows:
|
|
.Bl -enum
|
|
.It
|
|
The kernel will synthesize in memory a config file
|
|
with default directives for mounting
|
|
the root file system.
|
|
The logic for this is in
|
|
.Fn vfs_mountroot_conf0 .
|
|
.It
|
|
The kernel will first mount
|
|
.Xr devfs 5
|
|
as the root file system.
|
|
.It
|
|
Next, the kernel will parse the in-memory config file created in step 1
|
|
and try to mount the actual root file system.
|
|
See
|
|
.Sx FILE FORMAT
|
|
for the format of the config file.
|
|
.It
|
|
When the actual root file system is mounted,
|
|
.Xr devfs 5
|
|
will be re-mounted on the
|
|
.Pa /dev
|
|
directory.
|
|
.It
|
|
If a
|
|
.Pa /.mount.conf
|
|
file does not exist in the root file system which was
|
|
just mounted, the root mount logic stops here.
|
|
.It
|
|
If a
|
|
.Pa /.mount.conf
|
|
file exists in the root file system which was just mounted,
|
|
this file will be parsed, and the kernel will use this new config
|
|
file to try to re-mount the root file system.
|
|
See
|
|
.Sx FILE FORMAT
|
|
for the format of the config file.
|
|
.It
|
|
If the new root file system has a
|
|
.Pa /.mount
|
|
directory, the old root file system will be re-mounted
|
|
on
|
|
.Pa /.mount .
|
|
.It
|
|
The root mount logic will go back to step 4.
|
|
.El
|
|
.Pp
|
|
The root mount logic is recursive, and step 8 will
|
|
be repeated as long as each new root file system
|
|
which is mounted has a
|
|
.Pa /.mount.conf
|
|
file.
|
|
.Sh FILE FORMAT
|
|
The kernel parses each line in
|
|
.Pa .mount.conf
|
|
and then tries to perform the action specified on that line as soon as it is parsed.
|
|
.Bl -tag -width "XXXXXXXXXX"
|
|
.It Ic #
|
|
A line beginning with a # is a comment and is ignored.
|
|
.It Ic {FS}:{MOUNTPOINT} {OPTIONS}
|
|
The kernel will try to mount this in an
|
|
operation equivalent to:
|
|
.Bd -literal -offset indent
|
|
mount -t {FS} -o {OPTIONS} {MOUNTPOINT} /
|
|
.Ed
|
|
.Pp
|
|
If this is successfully mounted,
|
|
further lines in
|
|
.Pa .mount.conf
|
|
are ignored.
|
|
If all lines in
|
|
.Pa .mount.conf
|
|
have been processed and no root file system has been successfully
|
|
mounted, then the action specified by
|
|
.Ic .onfail
|
|
is performed.
|
|
.It Ic .ask
|
|
When the kernel processes this line, a
|
|
.Li mountroot>
|
|
command-line prompt is displayed.
|
|
At this prompt, the operator can enter the
|
|
the root mount.
|
|
.It Ic .md Ar file
|
|
Create a memory backed
|
|
.Xr md 4
|
|
virtual disk, using
|
|
.Ar file
|
|
as the backing store.
|
|
.It Ic .onfail Ar [panic|reboot|retry|continue]
|
|
If after parsing all the lines in
|
|
.Pa .mount.conf
|
|
the kernel is unable to mount a root file system,
|
|
the
|
|
.Ic .onfail
|
|
directive tells the kernel what action to perform.
|
|
.It Ic .timeout Ar N
|
|
Before trying to mount a root file system,
|
|
if the root mount device does not exist, wait at most
|
|
.Ar N
|
|
seconds for the device to appear before trying to mount it.
|
|
If
|
|
.Ic .timeout
|
|
is not specified, the default timeout is 3 seconds.
|
|
.El
|
|
.Sh EXAMPLES
|
|
The following example
|
|
.Pa .mount.conf
|
|
will direct the kernel to try mounting the root file system
|
|
first as an ISO CD9660 file system on
|
|
.Pa /dev/cd0 ,
|
|
then if that does not work, as an ISO CD9660 file system on
|
|
.Pa /dev/cd1 ,
|
|
and then if that does not work, as a UFS file system on
|
|
.Pa /dev/ada0s1a .
|
|
If that does not work, a
|
|
.Li mountroot>
|
|
command-line prompt will be displayed where the operator
|
|
can manually enter the root file system to mount.
|
|
Finally if that does not work, the kernel will panic.
|
|
.Bd -literal -offset indent
|
|
.Li .onfail panic
|
|
.Li .timeout 3
|
|
cd9660:/dev/cd0 ro
|
|
.Li .timeout 0
|
|
cd9660:/dev/cd1 ro
|
|
.Li .timeout 3
|
|
ufs:/dev/ada0s1a
|
|
.Li .ask
|
|
.Ed
|
|
.Pp
|
|
The following example
|
|
.Pa .mount.conf
|
|
will direct the kernel to create a
|
|
.Xr md 4
|
|
memory disk attached to the file
|
|
.Pa /data/OS-1.0.iso
|
|
and then mount the ISO CD9660 file system
|
|
on the md device which was just created.
|
|
The last line is a comment which is ignored.
|
|
.Bd -literal -offset indent
|
|
.Li .timeout 3
|
|
.Li .md /data/OS-1.0.iso
|
|
.Li cd9600:/dev/md# ro
|
|
.Li # Can also use cd9660:/dev/md0 ro
|
|
.Ed
|
|
.Pp
|
|
The following example
|
|
.Pa .mount.conf
|
|
will direct the kernel to create a
|
|
.Xr md 4
|
|
memory disk attached to the file
|
|
.Pa /data/base.ufs.uzip
|
|
and then mount the UFS file system
|
|
on the md uzip device which was just created
|
|
by the
|
|
.Xr geom_uzip 4
|
|
driver.
|
|
.Bd -literal -offset indent
|
|
.Li .md /data/base.ufs.uzip
|
|
.Li ufs:/dev/md#.uzip ro
|
|
.Li # Can also use ufs:/dev/md0.uzip ro
|
|
.Ed
|
|
.Pp
|
|
The following example
|
|
.Pa .mount.conf
|
|
will direct the kernel to do a unionfs
|
|
mount on a directory
|
|
.Pa /jail/freebsd-8-stable
|
|
which has a
|
|
.Xr chroot 2
|
|
environment.
|
|
.Bd -literal -offset indent
|
|
.Li .timeout 3
|
|
.Li unionfs:/jail/freebsd-8-stable
|
|
.Ed
|
|
.Sh NOTES
|
|
For each root file system which is mounted, a
|
|
.Pa /dev
|
|
directory
|
|
.Em must
|
|
exist so that the root mount logic can properly re-mount
|
|
.Xr devfs 5 .
|
|
If this directory does not exist, the system
|
|
may hang during the bootup process.
|
|
.Sh SEE ALSO
|
|
.Xr nmount 2 ,
|
|
.Xr md 4 ,
|
|
.Xr boot.config 5 ,
|
|
.Xr fstab 5 ,
|
|
.Xr boot 8 ,
|
|
.Xr loader 8 ,
|
|
.Xr mount 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
file first appeared in
|
|
.Fx 9.0 .
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
The root mount logic in the
|
|
.Fx
|
|
kernel which parses
|
|
.Pa /.mount.conf
|
|
was written by
|
|
.An Marcel Moolenaar Aq Mt marcel@FreeBSD.org .
|
|
This man page was written by
|
|
.An Craig Rodrigues Aq Mt rodrigc@FreeBSD.org .
|