[Qemu-devel] Re: patch to avoid space allocation for zero blocks in the qcow format

[Ben Pfaff]

Bakul Shah <address@hidden> writes:

> The below patch avoids allocating space in the qcow image
> format when a block of zeroes is being written.  No attempt
> is made to free up space if a previously written block of
> nonzero data is being overwritten with zeroes.

This optimization is only possible for base disks (those with no
parent).  Based on a quick glance at the diff, I am not sure
whether this change properly recognizes that.  Does it?
-- 
Ben Pfaff 
email: address@hidden
web: http://benpfaff.org