block/loop: add documentation for sysfs interface

Documentation has been compiled from git logs and by reading through
code.

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Aishwarya Pant 2018-02-17 11:43:04 +05:30 committed by Jonathan Corbet
parent 3bd640b735
commit 2d39f681bc

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What: /sys/block/loopX/loop/autoclear
Date: Aug, 2010
KernelVersion: v2.6.37
Contact: linux-block@vger.kernel.org
Description:
(RO) Shows if the device is in autoclear mode or not ( "1" or
"0"). Autoclear (if set) indicates that the loopback device will
self-distruct after last close.
What: /sys/block/loopX/loop/backing_file
Date: Aug, 2010
KernelVersion: v2.6.37
Contact: linux-block@vger.kernel.org
Description:
(RO) The path of the backing file that the loop device maps its
data blocks to.
What: /sys/block/loopX/loop/offset
Date: Aug, 2010
KernelVersion: v2.6.37
Contact: linux-block@vger.kernel.org
Description:
(RO) Start offset (in bytes).
What: /sys/block/loopX/loop/sizelimit
Date: Aug, 2010
KernelVersion: v2.6.37
Contact: linux-block@vger.kernel.org
Description:
(RO) The size (in bytes) that the block device maps, starting
from the offset.
What: /sys/block/loopX/loop/partscan
Date: Aug, 2011
KernelVersion: v3.10
Contact: linux-block@vger.kernel.org
Description:
(RO) Shows if automatic partition scanning is enabled for the
device or not ("1" or "0"). This can be requested individually
per loop device during its setup by setting LO_FLAGS_PARTSCAN in
in the ioctl request. By default, no partition tables are
scanned.
What: /sys/block/loopX/loop/dio
Date: Aug, 2015
KernelVersion: v4.10
Contact: linux-block@vger.kernel.org
Description:
(RO) Shows if direct IO is being used to access backing file or
not ("1 or "0").