On 09/13/2013 04:36 AM, Paolo Bonzini wrote: > Il 13/09/2013 12:25, Peter Lieven ha scritto: >> if the target has_zero_init = 0, but supports efficiently >> writing zeroes by unmapping we call bdrv_zeroize to >> avoid fully allocating the target. this currently >> is designed especially for iscsi. >> >> Signed-off-by: Peter Lieven <p...@kamp.de> >> --- >> qemu-img.c | 22 ++++++++++++++++------ >> 1 file changed, 16 insertions(+), 6 deletions(-) >> >> diff --git a/qemu-img.c b/qemu-img.c >> index 3e5e388..6eaddc6 100644 >> --- a/qemu-img.c >> +++ b/qemu-img.c >> @@ -1354,7 +1354,8 @@ static int img_convert(int argc, char **argv) >> } >> } >> >> - flags = BDRV_O_RDWR; >> + flags = BDRV_O_RDWR | BDRV_O_UNMAP; > > I think this should be a new command-line flag.
I agree - while 'sparse by default' may be reasonable, it is also feasible to want a mode that guarantees expansion rather than unmapped or sparse. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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