Re: [PATCH 1/2] qcow2: Make preallocate_co() resize the image to the correct size
On Tue 15 Sep 2020 11:29:22 AM CEST, Max Reitz wrote: > On 11.09.20 16:09, Alberto Garcia wrote: >> This function preallocates metadata structures and then extends the >> image to its new size, but that new size calculation is wrong because >> it doesn't take into account that the host_offset variable is always >> cluster-aligned. >> >> This problem can be reproduced with preallocation=metadata when the >> original size is not cluster-aligned but the new size is. In this case >> the final image size will be shorter than expected. >> >>qemu-img create -f qcow2 img.qcow2 31k >>qemu-img resize --preallocation=metadata img.qcow2 128k >> >> Signed-off-by: Alberto Garcia >> --- >> block/qcow2.c | 1 + >> tests/qemu-iotests/125 | 40 +- >> tests/qemu-iotests/125.out | 28 -- >> 3 files changed, 49 insertions(+), 20 deletions(-) > > The test additions make this test fail with compat=0.10. Are you OK > with disabling compat=0.10 by squashing this in? Yes, thanks Berto
Re: [PATCH 1/2] qcow2: Make preallocate_co() resize the image to the correct size
On 11.09.20 16:09, Alberto Garcia wrote: > This function preallocates metadata structures and then extends the > image to its new size, but that new size calculation is wrong because > it doesn't take into account that the host_offset variable is always > cluster-aligned. > > This problem can be reproduced with preallocation=metadata when the > original size is not cluster-aligned but the new size is. In this case > the final image size will be shorter than expected. > >qemu-img create -f qcow2 img.qcow2 31k >qemu-img resize --preallocation=metadata img.qcow2 128k > > Signed-off-by: Alberto Garcia > --- > block/qcow2.c | 1 + > tests/qemu-iotests/125 | 40 +- > tests/qemu-iotests/125.out | 28 -- > 3 files changed, 49 insertions(+), 20 deletions(-) The test additions make this test fail with compat=0.10. Are you OK with disabling compat=0.10 by squashing this in? diff --git a/tests/qemu-iotests/125 b/tests/qemu-iotests/125 index 1f35598b2b..894d53f2bd 100755 --- a/tests/qemu-iotests/125 +++ b/tests/qemu-iotests/125 @@ -43,6 +43,10 @@ get_image_size_on_host() _supported_fmt qcow2 _supported_proto file +# Growing a file with a backing file (without preallocation=full or +# =falloc) requires zeroing the newly added area, which is impossible +# to do quickly for v2 images, and hence is unsupported. +_unsupported_imgopts 'compat=0.10' if [ -z "$TEST_IMG_FILE" ]; then TEST_IMG_FILE=$TEST_IMG signature.asc Description: OpenPGP digital signature
Re: [PATCH 1/2] qcow2: Make preallocate_co() resize the image to the correct size
On 11.09.20 16:09, Alberto Garcia wrote: > This function preallocates metadata structures and then extends the > image to its new size, but that new size calculation is wrong because > it doesn't take into account that the host_offset variable is always > cluster-aligned. > > This problem can be reproduced with preallocation=metadata when the > original size is not cluster-aligned but the new size is. In this case > the final image size will be shorter than expected. > >qemu-img create -f qcow2 img.qcow2 31k >qemu-img resize --preallocation=metadata img.qcow2 128k > > Signed-off-by: Alberto Garcia > --- > block/qcow2.c | 1 + > tests/qemu-iotests/125 | 40 +- > tests/qemu-iotests/125.out | 28 -- > 3 files changed, 49 insertions(+), 20 deletions(-) Reviewed-by: Max Reitz signature.asc Description: OpenPGP digital signature
