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Re: [Qemu-block] [PATCH] qcow2: Flush pending discards before allocating
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-block] [PATCH] qcow2: Flush pending discards before allocating cluster |
Date: |
Fri, 8 May 2015 12:55:20 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 06.05.2015 um 13:29 hat Kevin Wolf geschrieben:
> Before a freed cluster can be reused, pending discards for this cluster
> must be processed.
>
> The original assumption was that this was not a problem because discards
> are only cached during discard/write zeroes operations, which are
> synchronous so that no concurrent write requests can cause cluster
> allocations.
>
> However, the discard/write zeroes operation itself can allocate a new L2
> table (and it has to in order to put zero flags there), so make sure we
> can cope with the situation.
>
> This fixes https://bugs.launchpad.net/bugs/1349972.
>
> Signed-off-by: Kevin Wolf <address@hidden>
Cc: address@hidden
Applied to my block branch.
Kevin