Am 13.09.2013 20:25, schrieb Eric Blake: > 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. > Ok, so do you find the proposed -S 0 bei Paolo a good choice? If this is supplied I would go as far as completly setting has_zero_init = 0 also for targets which default to 1. This would guaranteed exspansion and full allocation for all drivers.
Peter
