NetBSD-5.0.2/usr.sbin/puffs/rump_tmpfs/rump_tmpfs.8

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.Dd February 15, 2009
.Dt RUMP_TMPFS 8
.Os
.Sh NAME
.Nm rump_tmpfs
.Nd mount the tmpfs file system using a userspace server
.Sh SYNOPSIS
.Cd "file-system PUFFS"
.Cd "pseudo-device putter"
.Pp
.Nm
.Op options
.Ar special
.Ar node
.Sh DESCRIPTION
The
.Nm
utility can be used to mount tmpfs file systems.
It uses
.Xr rump 3
and
.Xr p2k 3
to facilitate running the file system as a server in userspace.
As opposed to
.Xr mount_tmpfs 8 ,
.Nm
does not use file system code within the kernel and therefore does
not require kernel support except
.Xr puffs 4 .
Apart from a minor speed penalty (starting from 10% and depending
on the workload and file system in question), there is no difference
to using in-kernel code.
.Pp
In case mounting a file system image from a regular file,
.Nm
does not require the use of
.Xr vnconfig 8
unlike kernel file systems.
Instead, the image path can be directly passed as the special file path.
The exception is if the image contains a disklabel.
In this case vnconfig is required to resolve the start offset for the
correct partition within the image.
.Pp
It is recommended that untrusted file system images be mounted with
.Nm
instead of
.Xr mount_tmpfs 8 .
Corrupt file system images commonly cause the file system
to crash the entire kernel, but with
.Nm
only the userspace server process will dump core.
.Pp
To use
.Nm
via
.Xr mount 8 ,
the flags
.Fl o Ar rump
and
.Fl t Ar tmpfs
should be given.
Similarly,
.Nm
is run instead of
.Xr mount_tmpfs 8
if
.Dq rump
is added to the options field of
.Xr fstab 5 .
.Pp
Please see
.Xr mount_tmpfs 8
for a full description of the available command line options.
.Sh SEE ALSO
.Xr p2k 3 ,
.Xr puffs 3 ,
.Xr rump 3 ,
.Xr mount_tmpfs 8
.Sh HISTORY
The
.Nm
utility first appeared in
.Nx 5.0 .
It is currently considered experimental.