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| H A D | iscsi.c | 9f0eb9e1 Thu Mar 10 12:55:50 GMT 2016 Kevin Wolf <kwolf@redhat.com> iscsi: Support BDRV_REQ_FUA
This replaces the existing hack in the iscsi driver that sent the FUA
bit in writethrough mode and ignored the following flush in order to
optimise the number of roundtrips (see commit 73b5394e).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
73b5394e Thu Apr 16 14:08:29 GMT 2015 Peter Lieven <pl@kamp.de> block/iscsi: optimize WRITE10/16 if cache.writeback is not set
SCSI allowes to tell the target to not return from a write command
if the date is not written to the disk. Use this so called FUA
bit if it is supported to optimize WRITE commands if writeback is
not allowed.
In this case qemu always issues a WRITE followed by a FLUSH. This
is 2 round trip times. If we set the FUA bit we can ignore the
following FLUSH.
Signed-off-by: Peter Lieven <pl@kamp.de>
Message-id: 1429193313-4263-6-git-send-email-pl@kamp.de
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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