Il 04/09/2012 09:05, Wenchao Xia ha scritto: >> That said, QEMU's internal bdrv_is_allocated function does have one not >> entirely appealing property: the block at start + *pnum might have the >> same state as the block at start + *pnum - 1, even if *pnum < length. >> We may want to work around this in libqblock, but we could also simply >> document it. >> >> Paolo >> > int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, > int nb_sectors,int *pnum) > will the issue happen when nb_sectors > *pnum? if so it seems a bug, > because caller is asking a range of sectors's allocation status, and > *pnum did not reflect the real status.
Actually it does. bdrv_is_allocated says it didn't find out anything about sector start + *pnum and later. >>> Either way, I think you are supplying too >>> many parameters for how I envision checking for allocated sectors. >> > yes, it is a bit confusing, how about: > > int qb_check_allocate_status(struct QBroker *broker, > struct QBlockState *qbs, > offset sector_start, > size_t sector_number, > size_t *pnum, > int *status) > user input sector_start and sector_number to ask check it in this range, > following parameter receive the status, return indicate exception. That's ok too. But do not use size_t for sectors. Testing, or reading, or writing 2 TB with a single call is more than enough. Paolo