On Thu, Apr 18, 2013 at 01:50:53PM +0800, Liu Yuan wrote: > @@ -184,6 +186,8 @@ typedef struct SheepdogInode { > uint32_t data_vdi_id[MAX_DATA_OBJS]; > } SheepdogInode; > > +static bool discard_supported = true;
Normally state should be part of BDRVSheepdogState so that it does not affect other sheepdog drives. Please confirm that all -drive file=sheepdog:... must either support discard or not support it. I asked this in an older version of the patch but wasn't sure if my question was clear. Imagine a scenario where you run two sheepdog clusters and want to connect one drive from each cluster to your VM. If one cluster uses outdated sheepdog software but the other is up-to-date, then it should still be possible to use discard on the up-to-date cluster. Stefan