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From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, mreitz@redhat.com
Subject: Re: [PATCH 0/6] vmdk: Fix zero cluster handling
Date: Tue, 5 May 2020 11:42:40 +0200	[thread overview]
Message-ID: <20200505094240.GG5759@linux.fritz.box> (raw)
In-Reply-To: <20200430133007.170335-1-kwolf@redhat.com>

Am 30.04.2020 um 15:30 hat Kevin Wolf geschrieben:
> What I was really investigating is why 055 was so slow. I couldn't solve
> that, but instead I found out that our VMDK code for zero clusters and
> write_zeroes was completely broken. Apart from segfaults when zero
> clusters were actually enabled, this caused a compressed backup target
> to result in a bigger file than uncompressed with VMDK.
> 
> This series tries to fix it (with one bonus performance patch).

Thanks for the review, fixed up the commit messages and applied.

If you were curious about the VMDK terminology, I looked it up and the
basic terms translate to qcow2 like this:

* grain directory = L1 table
* grain table = L2 table
* grain = cluster

"zeroed-grain GTE (grain table entry)" is the exact term used in the
VMDK spec for what we would call a zero cluster in qcow2.

Kevin



      parent reply	other threads:[~2020-05-05  9:44 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30 13:30 [PATCH 0/6] vmdk: Fix zero cluster handling Kevin Wolf
2020-04-30 13:30 ` [PATCH 1/6] vmdk: Rename VmdkMetaData.valid to new_allocation Kevin Wolf
2020-04-30 14:10   ` Eric Blake
2020-04-30 13:30 ` [PATCH 2/6] vmdk: Fix zero cluster allocation Kevin Wolf
2020-04-30 14:14   ` Eric Blake
2020-04-30 14:19   ` Eric Blake
2020-04-30 14:32     ` Kevin Wolf
2020-04-30 13:30 ` [PATCH 3/6] vmdk: Fix partial overwrite of zero cluster Kevin Wolf
2020-04-30 14:16   ` Eric Blake
2020-04-30 13:30 ` [PATCH 4/6] vmdk: Don't update L2 table for zero write on " Kevin Wolf
2020-04-30 14:17   ` Eric Blake
2020-04-30 13:30 ` [PATCH 5/6] vmdk: Flush only once in vmdk_L2update() Kevin Wolf
2020-04-30 14:18   ` Eric Blake
2020-04-30 13:30 ` [PATCH 6/6] iotests: vmdk: Enable zeroed_grained=on by default Kevin Wolf
2020-04-30 14:22   ` Eric Blake
2020-04-30 14:42     ` Kevin Wolf
2020-05-05  9:42 ` Kevin Wolf [this message]

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