Re: [Qemu-devel] [PATCH v6 4/9] qcow2: make refcount size calculation conservative

2017-05-09 Thread Stefan Hajnoczi
On Mon, May 08, 2017 at 11:26:18PM +0200, Max Reitz wrote: > On 08.05.2017 16:15, Stefan Hajnoczi wrote: > > The refcount metadata size calculation is inaccurate and can produce > > numbers that are too small. This is bad because we should calculate a > > conservative number - one that is guarante

Re: [Qemu-devel] [PATCH v6 4/9] qcow2: make refcount size calculation conservative

2017-05-08 Thread Max Reitz
On 08.05.2017 16:15, Stefan Hajnoczi wrote: > The refcount metadata size calculation is inaccurate and can produce > numbers that are too small. This is bad because we should calculate a > conservative number - one that is guaranteed to be large enough. > > This patch switches the approach to a f

Re: [Qemu-devel] [PATCH v6 4/9] qcow2: make refcount size calculation conservative

2017-05-08 Thread Max Reitz
On 08.05.2017 17:00, Eric Blake wrote: > On 05/08/2017 09:15 AM, Stefan Hajnoczi wrote: >> The refcount metadata size calculation is inaccurate and can produce >> numbers that are too small. This is bad because we should calculate a >> conservative number - one that is guaranteed to be large enoug

Re: [Qemu-devel] [PATCH v6 4/9] qcow2: make refcount size calculation conservative

2017-05-08 Thread Eric Blake
On 05/08/2017 09:15 AM, Stefan Hajnoczi wrote: > The refcount metadata size calculation is inaccurate and can produce > numbers that are too small. This is bad because we should calculate a > conservative number - one that is guaranteed to be large enough. > > This patch switches the approach to

[Qemu-devel] [PATCH v6 4/9] qcow2: make refcount size calculation conservative

2017-05-08 Thread Stefan Hajnoczi
The refcount metadata size calculation is inaccurate and can produce numbers that are too small. This is bad because we should calculate a conservative number - one that is guaranteed to be large enough. This patch switches the approach to a fixed point calculation because the existing equation i