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Re: [Qemu-block] [PATCH v3 1/3] qcow2: Document some maximum size constr
From: |
Alberto Garcia |
Subject: |
Re: [Qemu-block] [PATCH v3 1/3] qcow2: Document some maximum size constraints |
Date: |
Thu, 15 Nov 2018 16:17:47 +0100 |
User-agent: |
Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) |
On Wed 14 Nov 2018 12:03:17 AM CET, Eric Blake wrote:
> @@ -427,7 +451,9 @@ Standard Cluster Descriptor:
> Compressed Clusters Descriptor (x = 62 - (cluster_bits - 8)):
>
> Bit 0 - x-1: Host cluster offset. This is usually _not_ aligned to a
> - cluster or sector boundary!
> + cluster or sector boundary! If cluster_bits is
> + small enough that this field includes bits beyond
> + 55, those upper bits must be set to 0.
While I think that it's good to have a 56 bits upper limit for both
compressed and uncompressed clusters, I'm wondering: is it theoretically
possible to have data clusters above 64PB if they're all compressed?
Berto
- [Qemu-block] [PATCH for 3.1 v3 0/3] minor qcow2 compression improvements, Eric Blake, 2018/11/13
- [Qemu-block] [PATCH v3 3/3] iotests: Add new test 220 for max compressed cluster offset, Eric Blake, 2018/11/13
- [Qemu-block] [PATCH v3 1/3] qcow2: Document some maximum size constraints, Eric Blake, 2018/11/13
- Re: [Qemu-block] [PATCH v3 1/3] qcow2: Document some maximum size constraints,
Alberto Garcia <=
- [Qemu-block] [PATCH v3 2/3] qcow2: Don't allow overflow during cluster allocation, Eric Blake, 2018/11/13
- Re: [Qemu-block] [PATCH for 3.1 v3 0/3] minor qcow2 compression improvements, Kevin Wolf, 2018/11/14
- Re: [Qemu-block] [Qemu-devel] [PATCH for 3.1 v3 0/3] minor qcow2 compression improvements, Eric Blake, 2018/11/14