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 <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/93991bcc05e419368ee1e585c81057fb2c7c8d2b.1581955849.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/bfs.rst

@@ -1,4 +1,7 @@
-BFS FILESYSTEM FOR LINUX
+.. SPDX-License-Identifier: GPL-2.0
+
+========================
+BFS Filesystem for Linux
 ========================
 
 The BFS filesystem is used by SCO UnixWare OS for the /stand slice, which
@@ -9,18 +12,18 @@ 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:
+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:
+/dev/loop0 device by::
 
     # losetup -d /dev/loop0
 
-You can simplify mounting by just typing:
+You can simplify mounting by just typing::
 
     # mount -t bfs -o loop stand.img /mnt/stand
 
@@ -33,19 +36,19 @@ that modprobe is functioning. Beware that umount will not deallocate
 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:
+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:
+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:
+the magic number::
 
     # od -Ad -tx4 stand.img | more
 

Documentation/filesystems/index.rst

@@ -53,6 +53,7 @@ Documentation for filesystem implementations.
    autofs
    autofs-mount-control
    befs
+   bfs
    fuse
    overlayfs
    virtiofs