50e3590c44
Existing scripts and associated config such as rc.initdiskless, rc.d/var, and others, use mdmfs to create memory filesystems. That program accepts a size argument which allows SI suffixes and treats an unsuffixed number as a count of 512 byte sectors. That makes it difficult to convert existing scripts to use tmpfs instead of mdmfs, because tmpfs treats unsuffixed numbers as a count of bytes. The script logic to deal with existing user config that might include suffixed and unsuffixed numbers is... unpleasant. Also, there is no g'tee that tmpfs will be available. It is sometimes configured out of small-resource embedded systems to save memory and flash storage space. These changes enhance mdmfs(8) so that it accepts two new values for the 'md-device' arg: 'tmpfs' and 'auto'. With tmpfs, the program always uses tmpfs(5) (and fails if it's not available). With 'auto' the program prefers tmpfs, but falls back to using md(4) if tmpfs isn't available. It also handles the -s <size> argument so that the mdconfig interpetation of unsuffixed numbers applies when tmpfs is used as well, so that existing user config keeps working after a switch to tmpfs. A new rc setting, mfs_type, is added to etc/defaults/rc.conf to let users force the use of tmpfs or md; the default value is "auto". Differential Revision: https://reviews.freebsd.org/D12301
446 lines
9.8 KiB
Groff
446 lines
9.8 KiB
Groff
.\"
|
|
.\" Copyright (c) 2001 Dima Dorfman.
|
|
.\" 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 September 9, 2017
|
|
.Dt MDMFS 8
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mdmfs ,
|
|
.Nm mount_mfs
|
|
.Nd configure and mount an in-memory file system using the
|
|
.Xr md 4
|
|
driver or the
|
|
.Xr tmpfs 5
|
|
filesystem
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl DLlMNnPStTUX
|
|
.Op Fl a Ar maxcontig
|
|
.Op Fl b Ar block-size
|
|
.Op Fl c Ar blocks-per-cylinder-group
|
|
.Op Fl d Ar max-extent-size
|
|
.Op Fl E Ar path-mdconfig
|
|
.Op Fl e Ar maxbpg
|
|
.Op Fl F Ar file
|
|
.Op Fl f Ar frag-size
|
|
.Op Fl i Ar bytes
|
|
.Op Fl m Ar percent-free
|
|
.Op Fl O Ar optimization
|
|
.Op Fl o Ar mount-options
|
|
.Op Fl p Ar permissions
|
|
.Op Fl s Ar size
|
|
.Op Fl T Ar fstype
|
|
.Op Fl v Ar version
|
|
.Op Fl w Ar user : Ns Ar group
|
|
.Ar md-device
|
|
.Ar mount-point
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility is designed to be a work-alike and look-alike of the deprecated
|
|
.Xr mount_mfs 8 .
|
|
The end result is essentially the same,
|
|
but is accomplished in a completely different way.
|
|
Based on
|
|
.Ar md-device ,
|
|
the
|
|
.Nm
|
|
utility either creates a
|
|
.Xr tmpfs 5
|
|
filesystem, or it configures an
|
|
.Xr md 4
|
|
disk using
|
|
.Xr mdconfig 8 ,
|
|
puts a UFS file system on it (unless
|
|
.Fl P
|
|
was specified) using
|
|
.Xr newfs 8 ,
|
|
and mounts it using
|
|
.Xr mount 8 .
|
|
It can handle
|
|
.Xr geom_uzip 4
|
|
compressed disk images, as long as the kernel supports this GEOM class.
|
|
All the command line options are passed to the appropriate program
|
|
at the appropriate stage in order to achieve the desired effect.
|
|
.Pp
|
|
When
|
|
.Ar md-device
|
|
is `auto',
|
|
.Nm
|
|
uses
|
|
.Xr tmpfs 5
|
|
if it is present in the kernel or can be loaded as a module,
|
|
otherwise it falls back to using
|
|
.Xr md 4
|
|
auto-unit as if `md' had been specified.
|
|
.Pp
|
|
When
|
|
.Ar md-device
|
|
is `tmpfs',
|
|
.Nm
|
|
mounts a
|
|
.Xr tmpfs 5
|
|
filesystem, translating the
|
|
.Fl s
|
|
size option, if present, into a `-o size=' mount option.
|
|
Any
|
|
.Fl o
|
|
options on the command line are passed through to the
|
|
.Xr tmpfs 5
|
|
mount.
|
|
Options specific to
|
|
.Xr mdconfig 8
|
|
or
|
|
.Xr newfs 8
|
|
are ignored.
|
|
.Pp
|
|
When
|
|
.Ar md-device
|
|
does not result in
|
|
.Xr tmpfs 5
|
|
being used, then an
|
|
.Xr md 4
|
|
device is configured instead.
|
|
By default,
|
|
.Nm
|
|
creates a swap-based
|
|
.Pq Dv MD_SWAP
|
|
disk with soft-updates enabled
|
|
and mounts it on
|
|
.Ar mount-point .
|
|
It uses the
|
|
.Xr md 4
|
|
device specified by
|
|
.Ar md-device .
|
|
If
|
|
.Ar md-device
|
|
is
|
|
.Ql md
|
|
(no unit number),
|
|
it will use
|
|
.Xr md 4 Ns 's
|
|
auto-unit feature to automatically select an unused device.
|
|
Unless otherwise specified with one of the options below,
|
|
it uses the default arguments to all the helper programs.
|
|
.Pp
|
|
The following options are available.
|
|
Where possible,
|
|
the option letter matches the one used by
|
|
.Xr mount_mfs 8
|
|
for the same thing.
|
|
.Bl -tag -width indent
|
|
.It Fl a Ar maxcontig
|
|
Specify the maximum number of contiguous blocks that will be laid
|
|
out before forcing a rotational delay
|
|
(see the
|
|
.Fl d
|
|
option).
|
|
.It Fl b Ar block-size
|
|
The block size of the file system, in bytes.
|
|
.It Fl c Ar blocks-per-cylinder-group
|
|
The number of blocks per cylinder group in the file system.
|
|
.It Fl D
|
|
If not using auto-unit,
|
|
do not run
|
|
.Xr mdconfig 8
|
|
to try to detach the unit before attaching it.
|
|
.It Fl d Ar max-extent-size
|
|
The file system may choose to store large files using extents.
|
|
This parameter specifies the largest extent size that may be
|
|
used.
|
|
It is presently limited to its default value which is 16
|
|
times the file system blocksize.
|
|
.It Fl E Ar path-mdconfig
|
|
Use
|
|
.Ar path-mdconfig
|
|
as a location of the
|
|
.Xr mdconfig 8
|
|
utility.
|
|
.It Fl e Ar maxbpg
|
|
Indicate the maximum number of blocks any single file can allocate
|
|
out of a cylinder group before it is forced to begin allocating
|
|
blocks from another cylinder group.
|
|
.It Fl F Ar file
|
|
Create a vnode-backed
|
|
.Pq Dv MD_VNODE
|
|
memory disk backed by
|
|
.Ar file .
|
|
.It Fl f Ar frag-size
|
|
The fragment size of the file system in bytes.
|
|
.It Fl i Ar bytes
|
|
Number of bytes per inode.
|
|
.It Fl l
|
|
Enable multilabel MAC on the new file system.
|
|
.It Fl L
|
|
Show the output of the helper programs.
|
|
By default,
|
|
it is sent to
|
|
.Pa /dev/null .
|
|
.It Fl M
|
|
Create a
|
|
.Xr malloc 9
|
|
backed disk
|
|
.Pq Dv MD_MALLOC
|
|
instead of a swap-backed disk.
|
|
.It Fl m Ar percent-free
|
|
The percentage of space reserved for the superuser.
|
|
.It Fl N
|
|
Do not actually run the helper programs.
|
|
This is most useful in conjunction with
|
|
.Fl X .
|
|
.It Fl n
|
|
Do not create a
|
|
.Pa .snap
|
|
directory on the new file system.
|
|
.It Fl O Ar optimization
|
|
Select the optimization preference;
|
|
valid choices are
|
|
.Cm space
|
|
and
|
|
.Cm time ,
|
|
which will optimize for minimum space fragmentation and
|
|
minimum time spent allocating blocks,
|
|
respectively.
|
|
.It Fl o Ar mount-options
|
|
Specify the mount options with which to mount the file system.
|
|
See
|
|
.Xr mount 8
|
|
for more information.
|
|
.It Fl P
|
|
Preserve the existing file system;
|
|
do not run
|
|
.Xr newfs 8 .
|
|
This only makes sense if
|
|
.Fl F
|
|
is specified to create a vnode-backed disk.
|
|
.It Fl p Ar permissions
|
|
Set the file (directory) permissions of the mount point
|
|
.Ar mount-point
|
|
to
|
|
.Ar permissions .
|
|
The
|
|
.Ar permissions
|
|
argument can be in any of the mode formats recognized by
|
|
.Xr chmod 1 .
|
|
If symbolic permissions are specified,
|
|
the operation characters
|
|
.Dq +
|
|
and
|
|
.Dq -
|
|
are interpreted relative to the initial permissions of
|
|
.Dq a=rwx .
|
|
.It Fl S
|
|
Do not enable soft-updates on the file system.
|
|
.It Fl s Ar size
|
|
Specify the size of the disk to create.
|
|
This only makes sense if
|
|
.Fl F
|
|
is
|
|
.Em not
|
|
specified.
|
|
That is,
|
|
this will work when the backing storage is some form of
|
|
memory, as opposed to a fixed-size file.
|
|
The size may include the usual SI suffixes (k, m, g, t, p).
|
|
A number without a suffix is interpreted as a count of 512-byte sectors.
|
|
.It Fl t
|
|
Turn on the TRIM enable flag for
|
|
.Xr newfs 8 .
|
|
When used with a file system that issue BIO_DELETE bio requests,
|
|
.Xr md 4
|
|
returns deleted blocks to the system memory pool.
|
|
.It Fl T Ar fstype
|
|
Specify a file system type for a vnode-backed memory disk.
|
|
Any file system supported by
|
|
.Xr mount 8
|
|
command can be specified.
|
|
This option only makes sense when
|
|
.Fl F
|
|
and
|
|
.Fl P
|
|
are used.
|
|
.It Fl U
|
|
Enable soft-updates on the file system.
|
|
This is the default, and is accepted only
|
|
for compatibility.
|
|
It is only really useful to negate the
|
|
.Fl S
|
|
flag, should such a need occur.
|
|
.It Fl v Ar version
|
|
Specify the UFS version number for use on the file system; it may be
|
|
either
|
|
.Dv 1
|
|
or
|
|
.Dv 2 .
|
|
The default is derived from the default of the
|
|
.Xr newfs 8
|
|
command.
|
|
.It Fl w Ar user : Ns Ar group
|
|
Set the owner and group to
|
|
.Ar user
|
|
and
|
|
.Ar group ,
|
|
respectively.
|
|
The arguments have the same semantics as with
|
|
.Xr chown 8 ,
|
|
but specifying just a
|
|
.Ar user
|
|
or just a
|
|
.Ar group
|
|
is not supported.
|
|
.It Fl X
|
|
Print what command will be run before running it, and
|
|
other assorted debugging information.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fl F
|
|
and
|
|
.Fl s
|
|
options are passed to
|
|
.Xr mdconfig 8
|
|
as
|
|
.Fl f
|
|
and
|
|
.Fl s ,
|
|
respectively.
|
|
The
|
|
.Fl a , b , c , d , e , f , i , m
|
|
and
|
|
.Fl n
|
|
options are passed to
|
|
.Xr newfs 8
|
|
with the same letter.
|
|
The
|
|
.Fl O
|
|
option is passed to
|
|
.Xr newfs 8
|
|
as
|
|
.Fl o .
|
|
The
|
|
.Fl o
|
|
option is passed to
|
|
.Xr mount 8
|
|
with the same letter.
|
|
The
|
|
.Fl T
|
|
option is passed to
|
|
.Xr mount 8
|
|
as
|
|
.Fl t .
|
|
For information on semantics, refer to the documentation of the programs
|
|
that the options are passed to.
|
|
.Sh EXAMPLES
|
|
Create and mount a 32 megabyte swap-backed file system on
|
|
.Pa /tmp :
|
|
.Pp
|
|
.Dl "mdmfs -s 32m md /tmp"
|
|
.Pp
|
|
The same file system created as an entry in
|
|
.Pa /etc/fstab :
|
|
.Pp
|
|
.Dl "md /tmp mfs rw,-s32m 2 0"
|
|
.Pp
|
|
Create and mount a 16 megabyte malloc-backed file system on
|
|
.Pa /tmp
|
|
using the
|
|
.Pa /dev/md1
|
|
device;
|
|
furthermore,
|
|
do not use soft-updates on it and mount it
|
|
.Cm async :
|
|
.Pp
|
|
.Dl "mdmfs -M -S -o async -s 16m md1 /tmp"
|
|
.Pp
|
|
Create and mount a
|
|
.Xr geom_uzip 4
|
|
based compressed disk image:
|
|
.Pp
|
|
.Dl "mdmfs -P -F foo.uzip -oro md.uzip /tmp/"
|
|
.Pp
|
|
Mount the same image, specifying the
|
|
.Pa /dev/md1
|
|
device:
|
|
.Pp
|
|
.Dl "mdmfs -P -F foo.uzip -oro md1.uzip /tmp/"
|
|
.Pp
|
|
Configure a vnode-backed file system and mount its first partition,
|
|
using automatic device numbering:
|
|
.Pp
|
|
.Dl "mdmfs -P -F foo.img mds1a /tmp/"
|
|
.Pp
|
|
Mount a vnode-backed cd9660 file system using automatic device numbering:
|
|
.Pp
|
|
.Dl "mdmfs -T cd9660 -P -F foo.iso md /tmp"
|
|
.Sh COMPATIBILITY
|
|
The
|
|
.Nm
|
|
utility, while designed to be compatible with
|
|
.Xr mount_mfs 8 ,
|
|
can be useful by itself.
|
|
Since
|
|
.Xr mount_mfs 8
|
|
had some silly defaults, a
|
|
.Dq compatibility
|
|
mode is provided for the case where bug-to-bug compatibility is desired.
|
|
.Pp
|
|
Compatibility is enabled by starting
|
|
.Nm
|
|
with the name
|
|
.Li mount_mfs
|
|
or
|
|
.Li mfs
|
|
(as returned by
|
|
.Xr getprogname 3 ) .
|
|
In this mode, the following behavior, as done by
|
|
.Xr mount_mfs 8 ,
|
|
is duplicated:
|
|
.Bl -bullet -offset indent
|
|
.It
|
|
The file mode of
|
|
.Ar mount-point
|
|
is set by default to
|
|
.Li 01777
|
|
as if
|
|
.Fl p Ar 1777
|
|
was given on the command line.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr md 4 ,
|
|
.Xr fstab 5 ,
|
|
.Xr tmpfs 5 ,
|
|
.Xr mdconfig 8 ,
|
|
.Xr mount 8 ,
|
|
.Xr newfs 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
utility appeared in
|
|
.Fx 5.0 .
|
|
.Sh AUTHORS
|
|
.An Dima Dorfman
|