On 23.04.20 17:01, Kevin Wolf wrote: > The BDRV_REQ_ZERO_WRITE is currently implemented in a way that first the > image is possibly preallocated and then the zero flag is added to all > clusters. This means that a copy-on-write operation may be needed when > writing to these clusters, despite having used preallocation, negating > one of the major benefits of preallocation. > > Instead, try to forward the BDRV_REQ_ZERO_WRITE to the protocol driver, > and if the protocol driver can ensure that the new area reads as zeros, > we can skip setting the zero flag in the qcow2 layer. > > Unfortunately, the same approach doesn't work for metadata > preallocation, so we'll still set the zero flag there. > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > --- > block/qcow2.c | 22 +++++++++++++++++++--- > tests/qemu-iotests/274.out | 4 ++-- > 2 files changed, 21 insertions(+), 5 deletions(-)
Oh, nice. I didn’t think you (or anyone else for that matter) would actually do this. :) With the errp thing fixed: Reviewed-by: Max Reitz <mre...@redhat.com>
signature.asc
Description: OpenPGP digital signature
