From: "Denis V. Lunev" <[email protected]> tail_padding_bytes is calculated wrong. F.e. for offset = 0 bytes = 2048 align = 512 we will have tail_padding_bytes = 512 which is definitely wrong. The patch fixes that arithmetics.
Fortunately this problem is harmless, we will have 1 extra allocation and free thus there is no need to put this into stable. The problem is here from the very beginning. Signed-off-by: Denis V. Lunev <[email protected]> CC: Stefan Hajnoczi <[email protected]> CC: Fam Zheng <[email protected]> Reviewed-by: Eric Blake <[email protected]> Signed-off-by: Kevin Wolf <[email protected]> --- block/io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/io.c b/block/io.c index 80d6c62..40bd94f 100644 --- a/block/io.c +++ b/block/io.c @@ -1444,7 +1444,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child, int ret = 0; head_padding_bytes = offset & (align - 1); - tail_padding_bytes = align - ((offset + bytes) & (align - 1)); + tail_padding_bytes = (align - (offset + bytes)) & (align - 1); assert(flags & BDRV_REQ_ZERO_WRITE); -- 1.8.3.1
