Re: [Qemu-devel] [PATCH v2] qcow2: Flush image after creation

[Kevin Wolf]

Am 24.10.2013 um 20:35 hat Max Reitz geschrieben:
> Opening the qcow2 image with BDRV_O_NO_FLUSH prevents any flushes during
> the image creation. This means that the image has not yet been flushed
> to disk when qemu-img create exits. This flush is delayed until the next
> operation on the image involving opening it without BDRV_O_NO_FLUSH and
> closing (or directly flushing) it. For large images and/or images with a
> small cluster size and preallocated metadata, this flush may take a
> significant amount of time and may occur unexpectedly.
> 
> Reopening the image without BDRV_O_NO_FLUSH right before the end of
> qcow2_create2() results in hoisting the potentially costly flush into
> the image creation, which is expected to take some time (whereas
> successive image operations may be not).
> 
> Signed-off-by: Max Reitz <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>

Thanks, applied to the block branch.

Kevin