1*1687d771SAlexander Ziaee.\" 2*1687d771SAlexander Ziaee.\" Copyright (c) 2008 Daniel Gerzo 3*1687d771SAlexander Ziaee.\" All rights reserved. 4*1687d771SAlexander Ziaee.\" 5*1687d771SAlexander Ziaee.\" Redistribution and use in source and binary forms, with or without 6*1687d771SAlexander Ziaee.\" modification, are permitted provided that the following conditions 7*1687d771SAlexander Ziaee.\" are met: 8*1687d771SAlexander Ziaee.\" 1. Redistributions of source code must retain the above copyright 9*1687d771SAlexander Ziaee.\" notice, this list of conditions and the following disclaimer. 10*1687d771SAlexander Ziaee.\" 2. Redistributions in binary form must reproduce the above copyright 11*1687d771SAlexander Ziaee.\" notice, this list of conditions and the following disclaimer in the 12*1687d771SAlexander Ziaee.\" documentation and/or other materials provided with the distribution. 13*1687d771SAlexander Ziaee.\" 14*1687d771SAlexander Ziaee.\" THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15*1687d771SAlexander Ziaee.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16*1687d771SAlexander Ziaee.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17*1687d771SAlexander Ziaee.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18*1687d771SAlexander Ziaee.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19*1687d771SAlexander Ziaee.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20*1687d771SAlexander Ziaee.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21*1687d771SAlexander Ziaee.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22*1687d771SAlexander Ziaee.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23*1687d771SAlexander Ziaee.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24*1687d771SAlexander Ziaee.\" 25*1687d771SAlexander Ziaee.Dd March 15, 2022 26*1687d771SAlexander Ziaee.Dt NULLFS 4 27*1687d771SAlexander Ziaee.Os 28*1687d771SAlexander Ziaee.Sh NAME 29*1687d771SAlexander Ziaee.Nm nullfs 30*1687d771SAlexander Ziaee.Nd "null file system" 31*1687d771SAlexander Ziaee.Sh SYNOPSIS 32*1687d771SAlexander ZiaeeTo enable support for this driver, 33*1687d771SAlexander Ziaeeplace the following line in the kernel configuration file: 34*1687d771SAlexander Ziaee.Bd -ragged -offset indent 35*1687d771SAlexander Ziaee.Cd "options NULLFS" 36*1687d771SAlexander Ziaee.Ed 37*1687d771SAlexander Ziaee.Pp 38*1687d771SAlexander ZiaeeAlternatively, to load the driver as a 39*1687d771SAlexander Ziaeemodule at boot time, place the following line in 40*1687d771SAlexander Ziaee.Xr loader.conf 5 : 41*1687d771SAlexander Ziaee.Bd -literal -offset indent 42*1687d771SAlexander Ziaeenullfs_load="YES" 43*1687d771SAlexander Ziaee.Ed 44*1687d771SAlexander Ziaee.Sh DESCRIPTION 45*1687d771SAlexander ZiaeeThe 46*1687d771SAlexander Ziaee.Nm 47*1687d771SAlexander Ziaeedriver will permit the 48*1687d771SAlexander Ziaee.Fx 49*1687d771SAlexander Ziaeekernel to mount a loopback file system sub-tree. 50*1687d771SAlexander Ziaee.Sh EXAMPLES 51*1687d771SAlexander ZiaeeTo mount a 52*1687d771SAlexander Ziaee.Nm 53*1687d771SAlexander Ziaeefile system: 54*1687d771SAlexander Ziaee.Pp 55*1687d771SAlexander Ziaee.Dl "mount_nullfs /usr/ports /home/devel/ports" 56*1687d771SAlexander Ziaee.Pp 57*1687d771SAlexander ZiaeeIt is also possible to define an entry in 58*1687d771SAlexander Ziaee.Xr fstab 5 59*1687d771SAlexander Ziaeethat looks similar to: 60*1687d771SAlexander Ziaee.Pp 61*1687d771SAlexander Ziaee.Bd -literal 62*1687d771SAlexander Ziaee/usr/ports /home/devel/ports nullfs rw 0 0 63*1687d771SAlexander Ziaee.Ed 64*1687d771SAlexander Ziaee.Sh SEE ALSO 65*1687d771SAlexander Ziaee.Xr fstab 5 , 66*1687d771SAlexander Ziaee.Xr mount_nullfs 8 67*1687d771SAlexander Ziaee.Sh HISTORY 68*1687d771SAlexander ZiaeeThe 69*1687d771SAlexander Ziaee.Nm 70*1687d771SAlexander Ziaeelayer first appeared in 71*1687d771SAlexander Ziaee.Bx 4.4 . 72*1687d771SAlexander Ziaee.Sh AUTHORS 73*1687d771SAlexander Ziaee.An -nosplit 74*1687d771SAlexander ZiaeeThe 75*1687d771SAlexander Ziaee.Nm 76*1687d771SAlexander Ziaeekernel implementation was written by 77*1687d771SAlexander Ziaee.An John Heideman . 78*1687d771SAlexander Ziaee.Pp 79*1687d771SAlexander ZiaeeThis manual page was written by 80*1687d771SAlexander Ziaee.An Daniel Gerzo Aq Mt danger@FreeBSD.org . 81