block: don't lose data from last incomplete sector

To read the last sector that is not aligned to sector boundary, current
code for growable backends, since commit 893a8f6 "block: Produce zeros
when protocols reading beyond end of file", drops the data and directly
returns zeroes. That is incorrect.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Fam Zheng 2013-09-18 19:14:14 +08:00 committed by Stefan Hajnoczi
parent 0f39ac9a07
commit bcb9d66e85

View File

@ -2669,7 +2669,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
goto out;
}
total_sectors = len >> BDRV_SECTOR_BITS;
total_sectors = (len + BDRV_SECTOR_SIZE - 1) >> BDRV_SECTOR_BITS;
max_nb_sectors = MAX(0, total_sectors - sector_num);
if (max_nb_sectors > 0) {
ret = drv->bdrv_co_readv(bs, sector_num,