Am 02.10.2013 17:13, schrieb Paolo Bonzini: > Il 02/10/2013 17:06, Stefan Hajnoczi ha scritto: >> Sorry I didn't review this earlier but this flag looks hacky and I'm not >> confident about merging the patch yet. >> >> The patch makes me wonder if the raw_bsd driver should avoid calling >> bs->file itself: >> >> return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | >> (sector_num << BDRV_SECTOR_BITS); >> >> Let block.c:bdrv_co_get_block_status() call down into bs->file. >> >> The problem is then the protocol cannot report unallocated sectors with >> this approach. >> >> I think we want to preserve bs' offset while taking the other flags from >> bs->file (DATA, ZERO). > This would cause other changes. For example, a qcow2 with full metadata > preallocation (i.e. all L2 tables are there but it points to holes) > would not return DATA anymore. I think this is wrong, and especially a > change from the old is_allocated API. > > However, a variant on this idea could be to return > > BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | > (sector_num << BDRV_SECTOR_BITS); > > and then BDRV_BLOCK_RAW would mean "take DATA and ZERO from bs->file". I am fine with that.
Peter
