If bdrv_block_status_above() fails, we are aborting the convert
process but failing to print an error message. Broken in commit
690c7301 (v2.4) when rewriting convert's logic.
Discovered when teaching nbdkit to support NBD_CMD_BLOCK_STATUS, and
accidentally violating the protocol by returning more than one extent
in spite of qemu asking for NBD_CMD_FLAG_REQ_ONE. The qemu NBD code
should probably handle the server's non-compliance more gracefully
than failing with EINVAL, but qemu-img shouldn't be silently
squelching any block status failures. It doesn't help that qemu 3.1
masks the qemu-img bug with extra noise that the nbd code is dumping
to stderr (that noise was cleaned up in d8b4bad8).
Reported-by: Richard W.M. Jones <rjo...@redhat.com>
Signed-off-by: Eric Blake <ebl...@redhat.com>
Message-Id: <20190323212639.579-2-ebl...@redhat.com>
Reviewed-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
qemu-img.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/qemu-img.c b/qemu-img.c
index 8ee63daeaeb..03a9a10dec1 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1630,6 +1630,8 @@ static int convert_iteration_sectors(ImgConvertState *s,
int64_t sector_num)
count, &count, NULL, NULL);
}
if (ret < 0) {
+ error_report("error while reading block status of sector %" PRId64
+ ": %s", sector_num, strerror(-ret));
return ret;
}
n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
--
2.20.1
