Re: [RFC PATCH v2 25/26] qcow2: Allow preallocation and backing files if extended_l2 is set

2019-11-05 Thread Max Reitz
On 26.10.19 23:25, Alberto Garcia wrote: > Traditional qcow2 images don't allow preallocation if a backing file > is set. This is because once a cluster is allocated there is no way to > tell that its data should be read from the backing file. > > Extended L2 entries have individual allocation bit

[RFC PATCH v2 25/26] qcow2: Allow preallocation and backing files if extended_l2 is set

2019-10-26 Thread Alberto Garcia
Traditional qcow2 images don't allow preallocation if a backing file is set. This is because once a cluster is allocated there is no way to tell that its data should be read from the backing file. Extended L2 entries have individual allocation bits for each subcluster, and therefore it is perfectl