----- Original Message -----
> From: "Fam Zheng" <f...@redhat.com>
> To: qemu-devel@nongnu.org
> Cc: stefa...@redhat.com, kw...@redhat.com, "Miroslav Rezanina"
> <mreza...@redhat.com>
> Sent: Wednesday, November 13, 2013 5:04:18 AM
> Subject: [PATCH] qemu-img: Fix content mismatch offset of image compare
>
> We were lucky to pass qemu-iotests 048 (qemu-img compare case) but when
> I tried to run with TEST_DIR=/tmp (tmpfs), it fails with a very weird
> mismatch offset. This fixes the bug.
>
> In the if branch, setting ret to 1 before using it makes dead code in
> the next line: pnum is never added to mismatch offset even if ret was 0.
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> qemu-img.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/qemu-img.c b/qemu-img.c
> index bf3fb4f..2bab20d 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -1020,10 +1020,10 @@ static int img_compare(int argc, char **argv)
> }
> ret = compare_sectors(buf1, buf2, nb_sectors, &pnum);
> if (ret || pnum != nb_sectors) {
> - ret = 1;
> qprintf(quiet, "Content mismatch at offset %" PRId64
> "!\n",
> sectors_to_bytes(
> ret ? sector_num : sector_num + pnum));
> + ret = 1;
> goto out;
> }
> }
> --
> 1.8.4.2
>
>
Correct fix, setting variable to constant before test is definitely wrong.
Reviewed-by: Miroslav Rezanina <mreza...@redhat.com>
--
Miroslav Rezanina
Software Engineer - Virtualization Team
