mirror: Fix qiov size for short requests
When mirroring an image of a size that is not a multiple of the
mirror job granularity, the last request would have the right nb_sectors
argument, but a qiov that is rounded up to the next multiple of the
granularity. Don't do this.
This fixes a segfault that is caused by raw-posix being confused by this
and allocating a buffer with request length, but operating on it with
qiov length.
[s/Driver/Drive/ in qemu-iotests 041 as suggested by Eric
--Stefan]
Reported-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/block/mirror.c b/block/mirror.c
index 6c3ee70..c7a655f 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -265,9 +265,11 @@
next_sector = sector_num;
while (nb_chunks-- > 0) {
MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);
+ size_t remaining = (nb_sectors * BDRV_SECTOR_SIZE) - op->qiov.size;
+
QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);
s->buf_free_count--;
- qemu_iovec_add(&op->qiov, buf, s->granularity);
+ qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining));
/* Advance the HBitmapIter in parallel, so that we do not examine
* the same sector twice.
diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041
index 0815e19..005090e 100755
--- a/tests/qemu-iotests/041
+++ b/tests/qemu-iotests/041
@@ -217,6 +217,11 @@
test_small_buffer2 = None
test_large_cluster = None
+class TestSingleDriveUnalignedLength(TestSingleDrive):
+ image_len = 1025 * 1024
+ test_small_buffer2 = None
+ test_large_cluster = None
+
class TestMirrorNoBacking(ImageMirroringTestCase):
image_len = 2 * 1024 * 1024 # MB
diff --git a/tests/qemu-iotests/041.out b/tests/qemu-iotests/041.out
index 42147c0..24093bc 100644
--- a/tests/qemu-iotests/041.out
+++ b/tests/qemu-iotests/041.out
@@ -1,5 +1,5 @@
-..............................................
+......................................................
----------------------------------------------------------------------
-Ran 46 tests
+Ran 54 tests
OK
