From: Paolo Bonzini <pbonzini@redhat.com>
To: Alex Bligh <alex@alex.org.uk>
Cc: "nbd-general@lists.sourceforge.net"
<nbd-general@lists.sourceforge.net>,
Kevin Wolf <kwolf@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Pavel Borzenkov <pborzenkov@virtuozzo.com>,
"Stefan stefanha@redhat. com" <stefanha@redhat.com>,
"Denis V. Lunev" <den@openvz.org>, Wouter Verhelst <w@uter.be>
Subject: Re: [Qemu-devel] [Nbd] [PATCH 2/2] NBD proto: add GET_LBA_STATUS extension
Date: Thu, 24 Mar 2016 13:32:18 +0100 [thread overview]
Message-ID: <56F3DE52.7060502@redhat.com> (raw)
In-Reply-To: <6045D693-ADB5-4031-852B-CD9FA9BA8156@alex.org.uk>
On 24/03/2016 13:17, Alex Bligh wrote:
>>> >> * unallocated
>>> >> * zero
>>> >> * non-zero
>>> >>
>>> >> So the possible replies are a bitfield of those, with a '1' if it 'might'
>>> >> be in that state, i.e.
>>> >>
>>> >> 111 = no idea
>>> >> 110 = might be zero or unallocated, but isn't zero
>>> >> 011 = I know it's allocated, but I don't know whether it is zero or not
>> >
>> > How do you represent "definitely unallocated?"
> 100 is definitely allocated. The first '1' says it 'might' be in allocated state,
> but as we know it's NOT in any of the other states (next two zeroes), by a
> process of elimination, it's definitely unallocated. Similarly 010 and 001
> are the two other 'definite' states.
An unallocated block can still be definitely zero.
Paolo
next prev parent reply other threads:[~2016-03-24 12:32 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-23 14:16 [Qemu-devel] [PATCH 0/2] NBD protocol extensions: WRITE_ZEROES and GET_LBA_STATUS Denis V. Lunev
2016-03-23 14:16 ` [Qemu-devel] [PATCH 1/2] NBD proto: add WRITE_ZEROES extension Denis V. Lunev
2016-03-23 15:14 ` Eric Blake
2016-03-23 17:40 ` [Qemu-devel] [Nbd] " Wouter Verhelst
2016-03-24 7:16 ` [Qemu-devel] " Pavel Borzenkov
2016-03-24 7:36 ` [Qemu-devel] [Nbd] " Wouter Verhelst
2016-03-23 17:21 ` Wouter Verhelst
2016-03-24 7:57 ` Pavel Borzenkov
2016-03-24 8:26 ` Wouter Verhelst
2016-03-24 11:35 ` Pavel Borzenkov
2016-03-24 11:37 ` Paolo Bonzini
2016-03-24 12:31 ` Wouter Verhelst
2016-03-24 14:53 ` Eric Blake
2016-03-23 14:16 ` [Qemu-devel] [PATCH 2/2] NBD proto: add GET_LBA_STATUS extension Denis V. Lunev
2016-03-23 16:27 ` Eric Blake
2016-03-24 12:30 ` Pavel Borzenkov
2016-03-24 15:04 ` Eric Blake
2016-03-24 16:36 ` Pavel Borzenkov
2016-03-23 17:58 ` [Qemu-devel] [Nbd] " Wouter Verhelst
2016-03-23 18:14 ` Kevin Wolf
2016-03-24 8:25 ` Pavel Borzenkov
2016-03-24 8:41 ` Wouter Verhelst
2016-03-24 11:36 ` Pavel Borzenkov
2016-03-24 12:32 ` Wouter Verhelst
2016-03-24 8:43 ` Pavel Borzenkov
2016-03-24 9:33 ` Wouter Verhelst
2016-03-24 10:32 ` Alex Bligh
2016-03-24 11:58 ` Paolo Bonzini
2016-03-24 12:17 ` Alex Bligh
2016-03-24 12:32 ` Paolo Bonzini [this message]
2016-03-24 13:31 ` Alex Bligh
2016-03-24 13:32 ` Paolo Bonzini
2016-03-24 11:55 ` Paolo Bonzini
2016-03-24 12:43 ` Wouter Verhelst
2016-03-24 15:25 ` Eric Blake
2016-03-24 15:33 ` Paolo Bonzini
2016-03-24 15:53 ` Wouter Verhelst
2016-03-24 16:04 ` Eric Blake
2016-03-24 16:07 ` Kevin Wolf
2016-03-24 16:47 ` Wouter Verhelst
2016-03-29 9:38 ` Kevin Wolf
2016-03-29 9:53 ` Wouter Verhelst
2016-03-29 10:25 ` Paolo Bonzini
2016-03-24 22:08 ` [Qemu-devel] " Eric Blake
2016-03-25 8:49 ` [Qemu-devel] [Nbd] " Wouter Verhelst
2016-03-25 9:01 ` Alex Bligh
2016-03-28 15:58 ` Eric Blake
2016-04-04 10:32 ` Markus Pargmann
2016-04-04 10:18 ` Markus Pargmann
2016-04-04 16:54 ` Eric Blake
2016-04-04 22:17 ` Wouter Verhelst
2016-04-04 16:40 ` [Qemu-devel] " Eric Blake
2016-04-04 20:16 ` Denis V. Lunev
2016-04-04 20:36 ` [Qemu-devel] [Nbd] " Eric Blake
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