Re: [Qemu-devel] [PATCH] qemu-img: Require larger zero areas for sparse handling

2011-08-29 Thread Stefan Hajnoczi
On Fri, Aug 26, 2011 at 5:04 PM, Kevin Wolf wrote: > @@ -571,6 +573,48 @@ static int is_allocated_sectors(const uint8_t *buf, int > n, int *pnum) >  } > >  /* > + * Like is_allocated_sectors, but if the buffer starts with a used sector, > + * up to 'min' consecutive sectors containing zeros are i

[Qemu-devel] [PATCH] qemu-img: Require larger zero areas for sparse handling

2011-08-26 Thread Kevin Wolf
By default, require 4k of consecutive zero bytes for qemu-img to make the output file sparse by not issuing a write request for the zeroed parts. Add an -S option to allow users to tune this setting. This helps to avoid situations where a lot of zero sectors and data sectors are mixed and qemu-img