Re: [Qemu-devel] Qemu-img convert with -B

2011-04-28 Thread Kevin Wolf
Am 28.04.2011 04:06, schrieb Brad Campbell: On 27/04/11 22:02, Brad Campbell wrote: On 27/04/11 21:56, Kevin Wolf wrote: When you don't have a backing file, leaving an cluster unallocated means that it's zero. When you have a backing file, it could be anything. So if qemu-img convert wanted

Re: [Qemu-devel] Qemu-img convert with -B

2011-04-28 Thread Brad Campbell
On 28/04/11 14:36, Kevin Wolf wrote: Am 28.04.2011 04:06, schrieb Brad Campbell: On 27/04/11 22:02, Brad Campbell wrote: On 27/04/11 21:56, Kevin Wolf wrote: When you don't have a backing file, leaving an cluster unallocated means that it's zero. When you have a backing file, it could be

Re: [Qemu-devel] Qemu-img convert with -B

2011-04-27 Thread Stefan Hajnoczi
On Wed, Apr 27, 2011 at 4:05 AM, Brad Campbell lists2...@fnarfbargle.com wrote: I see there is a bug raised about the behaviour of qemu-img when used to convert using an output backing file. It allocates every sector whether or not it already exists in the output backing file. Please post

Re: [Qemu-devel] Qemu-img convert with -B

2011-04-27 Thread Brad Campbell
On 27/04/11 16:10, Stefan Hajnoczi wrote: On Wed, Apr 27, 2011 at 4:05 AM, Brad Campbell lists2...@fnarfbargle.com wrote: I see there is a bug raised about the behaviour of qemu-img when used to convert using an output backing file. It allocates every sector whether or not it already exists

Re: [Qemu-devel] Qemu-img convert with -B

2011-04-27 Thread Kevin Wolf
Am 27.04.2011 10:56, schrieb Brad Campbell: On 27/04/11 16:10, Stefan Hajnoczi wrote: On Wed, Apr 27, 2011 at 4:05 AM, Brad Campbell lists2...@fnarfbargle.com wrote: I see there is a bug raised about the behaviour of qemu-img when used to convert using an output backing file. It allocates

Re: [Qemu-devel] Qemu-img convert with -B

2011-04-27 Thread Brad Campbell
On 27/04/11 18:06, Kevin Wolf wrote: Am 27.04.2011 10:56, schrieb Brad Campbell: On 27/04/11 16:10, Stefan Hajnoczi wrote: On Wed, Apr 27, 2011 at 4:05 AM, Brad Campbell lists2...@fnarfbargle.com wrote: I see there is a bug raised about the behaviour of qemu-img when used to convert using

Re: [Qemu-devel] Qemu-img convert with -B

2011-04-27 Thread Kevin Wolf
Am 27.04.2011 15:45, schrieb Brad Campbell: On 27/04/11 18:06, Kevin Wolf wrote: Am 27.04.2011 10:56, schrieb Brad Campbell: On 27/04/11 16:10, Stefan Hajnoczi wrote: On Wed, Apr 27, 2011 at 4:05 AM, Brad Campbell lists2...@fnarfbargle.com wrote: I see there is a bug raised about the

Re: [Qemu-devel] Qemu-img convert with -B

2011-04-27 Thread Brad Campbell
On 27/04/11 21:56, Kevin Wolf wrote: When you don't have a backing file, leaving an cluster unallocated means that it's zero. When you have a backing file, it could be anything. So if qemu-img convert wanted to save this space, it would have to read from the backing file and leave the cluster

Re: [Qemu-devel] Qemu-img convert with -B

2011-04-27 Thread Brad Campbell
On 27/04/11 22:02, Brad Campbell wrote: On 27/04/11 21:56, Kevin Wolf wrote: When you don't have a backing file, leaving an cluster unallocated means that it's zero. When you have a backing file, it could be anything. So if qemu-img convert wanted to save this space, it would have to read from

[Qemu-devel] Qemu-img convert with -B

2011-04-26 Thread Brad Campbell
G'day all, I see there is a bug raised about the behaviour of qemu-img when used to convert using an output backing file. It allocates every sector whether or not it already exists in the output backing file. I'm walking my way through the block driver to try and get a handle on why this is