Re: [Qemu-devel] [PATCH v2 00/17] Add qemu-img subcommand to dump file metadata

[Paolo Bonzini]

Il 18/07/2013 10:17, Peter Lieven ha scritto:
> 
> maybe i have missed it in your patches, but would it be also possible to issue
> DISCARDZEROES ioctl on linux to return zero status for block devices also?

I think that would belong in your patches.  Once we have discard_zeroes,
we can use it as you suggested.

It is a good occasion to ask Linux developers for clarifications about
the meaning of discard_zeroes in the presence of misaligned requests.
But because of legacy, we might need to query the kernel for the
granularity ourselves---which is ugly because it is not available
through a ioctl, only sysfs.

Paolo