Il 06/03/2013 19:14, Jeff Cody ha scritto: > QCOW breaks with it using a normal raw posix file as a device. As a > test: qemu-img create -f qcow test.qcow 5G. Now run qemu with that > drive mounted, and try to partition and format it. QEMU now asserts. > > The nicety of being able to using truncate during a write call, > especially for VHDX (which can have relatively large block/cluster > sizes), so to grow the file sparsely in a dynamically allocated file.
Perhaps we need two APIs, "truncate" and "revalidate". Truncate should be a no-op if (!bs->growable). Revalidate could be called by the block_resize monitor command with no size specified. Paolo
