From ee68f34d7e7e553ffb74f09df0f3764fbfcf5d4b Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Mon, 17 Feb 2020 17:11:53 +0100 Subject: docs: filesystems: convert bfs.txt to ReST - Add a SPDX header; - Adjust document title; - Some whitespace fixes and new line breaks; - Mark literal blocks as such; - Add it to filesystems/index.rst. Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/93991bcc05e419368ee1e585c81057fb2c7c8d2b.1581955849.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet --- Documentation/filesystems/bfs.rst | 60 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 Documentation/filesystems/bfs.rst (limited to 'Documentation/filesystems/bfs.rst') diff --git a/Documentation/filesystems/bfs.rst b/Documentation/filesystems/bfs.rst new file mode 100644 index 000000000000..ce14b9018807 --- /dev/null +++ b/Documentation/filesystems/bfs.rst @@ -0,0 +1,60 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================== +BFS Filesystem for Linux +======================== + +The BFS filesystem is used by SCO UnixWare OS for the /stand slice, which +usually contains the kernel image and a few other files required for the +boot process. + +In order to access /stand partition under Linux you obviously need to +know the partition number and the kernel must support UnixWare disk slices +(CONFIG_UNIXWARE_DISKLABEL config option). However BFS support does not +depend on having UnixWare disklabel support because one can also mount +BFS filesystem via loopback:: + + # losetup /dev/loop0 stand.img + # mount -t bfs /dev/loop0 /mnt/stand + +where stand.img is a file containing the image of BFS filesystem. +When you have finished using it and umounted you need to also deallocate +/dev/loop0 device by:: + + # losetup -d /dev/loop0 + +You can simplify mounting by just typing:: + + # mount -t bfs -o loop stand.img /mnt/stand + +this will allocate the first available loopback device (and load loop.o +kernel module if necessary) automatically. If the loopback driver is not +loaded automatically, make sure that you have compiled the module and +that modprobe is functioning. Beware that umount will not deallocate +/dev/loopN device if /etc/mtab file on your system is a symbolic link to +/proc/mounts. You will need to do it manually using "-d" switch of +losetup(8). Read losetup(8) manpage for more info. + +To create the BFS image under UnixWare you need to find out first which +slice contains it. The command prtvtoc(1M) is your friend:: + + # prtvtoc /dev/rdsk/c0b0t0d0s0 + +(assuming your root disk is on target=0, lun=0, bus=0, controller=0). Then you +look for the slice with tag "STAND", which is usually slice 10. With this +information you can use dd(1) to create the BFS image:: + + # umount /stand + # dd if=/dev/rdsk/c0b0t0d0sa of=stand.img bs=512 + +Just in case, you can verify that you have done the right thing by checking +the magic number:: + + # od -Ad -tx4 stand.img | more + +The first 4 bytes should be 0x1badface. + +If you have any patches, questions or suggestions regarding this BFS +implementation please contact the author: + +Tigran Aivazian -- cgit