On Tue, 09/27 10:41, Kevin Wolf wrote: > Am 27.09.2016 um 04:20 hat Fam Zheng geschrieben: > > We already specified BDRV_O_UNMAP when opening images in 'qemu-img > > commit', but didn't turn on the "unmap" in the active commit job. This > > patch fixes that so that zeroed clusters in top image can be discarded > > which is desired in the virt-sparsify use case, where a temporary > > overlay is created and fstrim'ed before commiting back, to free space in > > the original image. > > > > The block-commit keeps the existing behavior. > > > > Signed-off-by: Fam Zheng <[email protected]> > > Is there a good reason for not using discard in an active commit if the > image was opened with BDRV_O_UNMAP? That is, wouldn't it make sense to > just set the unmap option for the mirror unconditionally and also for > block-commit? > > If there is a reason, we should probably add an option to block-commit, > but I still feels that enabling it should be the default then.
I didn't touch block-commit because I wasn't sure, but you made a good point, we can turn this on there too. Fam
