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authorDenis V. Lunev <den@openvz.org>2017-04-26 11:40:46 +0300
committerKevin Wolf <kwolf@redhat.com>2017-04-27 16:24:01 +0200
commitf13ce1be35b13f09c0a28269c74468f6766f0365 (patch)
tree0cca7d3265bdf9340eada4c3539d8913da814d49 /block/io.c
parentde234897b60e034ba94b307fc289e2dc692c9251 (diff)
downloadqemu-f13ce1be35b13f09c0a28269c74468f6766f0365.tar.gz
block: fix alignment calculations in bdrv_co_do_zero_pwritev
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 <den@openvz.org> CC: Stefan Hajnoczi <stefanha@redhat.com> CC: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/io.c')
-rw-r--r--block/io.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/block/io.c b/block/io.c
index 80d6c62a85..40bd94f323 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);