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| author | Kevin Wolf <kwolf@redhat.com> | 2018-08-14 11:52:25 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2018-08-15 12:50:39 +0200 |
| commit | 86fae10c64d642256cf019e6829929fa0d259c7a (patch) | |
| tree | 00b6eb0df7a2de3d00cb1ccc2b3a5d92da5688b6 | |
| parent | dbfdf6cb3625c68d0ea84ace4a786406cf43d4f3 (diff) | |
| download | qemu-86fae10c64d642256cf019e6829929fa0d259c7a.zip qemu-86fae10c64d642256cf019e6829929fa0d259c7a.tar.gz qemu-86fae10c64d642256cf019e6829929fa0d259c7a.tar.bz2 | |
mirror: Fail gracefully for source == target
blockdev-mirror with the same node for source and target segfaults
today: A node is in its own backing chain, so mirror_start_job() decides
that this is an active commit. When adding the intermediate nodes with
block_job_add_bdrv(), it starts the iteration through the subchain with
the backing file of source, though, so it never reaches target and
instead runs into NULL at the base.
While we could fix that by starting with source itself, there is no
point in allowing mirroring a node into itself and I wouldn't be
surprised if this caused more problems later.
So just check for this scenario and error out.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
| -rw-r--r-- | block/mirror.c | 5 | ||||
| -rwxr-xr-x | tests/qemu-iotests/041 | 6 | ||||
| -rw-r--r-- | tests/qemu-iotests/041.out | 4 |
3 files changed, 13 insertions, 2 deletions
diff --git a/block/mirror.c b/block/mirror.c index b48c3f8..dd5ca02 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -1499,6 +1499,11 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs, buf_size = DEFAULT_MIRROR_BUF_SIZE; } + if (bs == target) { + error_setg(errp, "Can't mirror node into itself"); + return; + } + /* In the case of active commit, add dummy driver to provide consistent * reads on the top, while disabling it in the intermediate nodes, and make * the backing chain writable. */ diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041 index c20ac7d..9336ab6 100755 --- a/tests/qemu-iotests/041 +++ b/tests/qemu-iotests/041 @@ -234,6 +234,12 @@ class TestSingleBlockdev(TestSingleDrive): result = self.vm.qmp("blockdev-add", **args) self.assert_qmp(result, 'return', {}) + def test_mirror_to_self(self): + result = self.vm.qmp(self.qmp_cmd, job_id='job0', + device=self.qmp_target, sync='full', + target=self.qmp_target) + self.assert_qmp(result, 'error/class', 'GenericError') + test_large_cluster = None test_image_not_found = None test_small_buffer2 = None diff --git a/tests/qemu-iotests/041.out b/tests/qemu-iotests/041.out index c28b392..e071d0b 100644 --- a/tests/qemu-iotests/041.out +++ b/tests/qemu-iotests/041.out @@ -1,5 +1,5 @@ -..................................................................................... +........................................................................................ ---------------------------------------------------------------------- -Ran 85 tests +Ran 88 tests OK |