diff options
| -rw-r--r-- | block.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/block.c b/block.c index e655052c8b..1615d89f0a 100644 --- a/block.c +++ b/block.c @@ -2571,7 +2571,35 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, } } - ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); + if (!(bs->zero_beyond_eof && bs->growable)) { + ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); + } else { + /* Read zeros after EOF of growable BDSes */ + int64_t len, total_sectors, max_nb_sectors; + + len = bdrv_getlength(bs); + if (len < 0) { + ret = len; + goto out; + } + + total_sectors = len >> 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, + MIN(nb_sectors, max_nb_sectors), qiov); + } else { + ret = 0; + } + + /* Reading beyond end of file is supposed to produce zeroes */ + if (ret == 0 && total_sectors < sector_num + nb_sectors) { + uint64_t offset = MAX(0, total_sectors - sector_num); + uint64_t bytes = (sector_num + nb_sectors - offset) * + BDRV_SECTOR_SIZE; + qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes); + } + } out: tracked_request_end(&req); |