From 7fcb8c89f063122864bd274fd673a70a0a802d93 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Wed, 6 Mar 2024 15:28:31 +0100 Subject: [PATCH] blockdev: Fix blockdev-snapshot-sync error reporting for no medium When external_snapshot_abort() rejects a BlockDriverState without a medium, it creates an error like this: error_setg(errp, "Device '%s' has no medium", device); Trouble is @device can be null. My system formats null as "(null)", but other systems might crash. Reproducer: 1. Create a block device without a medium -> {"execute": "blockdev-add", "arguments": {"driver": "host_cdrom", "node-name": "blk0", "filename": "/dev/sr0"}} <- {"return": {}} 3. Attempt to snapshot it -> {"execute":"blockdev-snapshot-sync", "arguments": { "node-name": "blk0", "snapshot-file":"/tmp/foo.qcow2","format":"qcow2"}} <- {"error": {"class": "GenericError", "desc": "Device '(null)' has no medium"}} Broken when commit 0901f67ecdb made @device optional. Use bdrv_get_device_or_node_name() instead. Now it fails as it should: <- {"error": {"class": "GenericError", "desc": "Device 'blk0' has no medium"}} Fixes: 0901f67ecdb7 ("qmp: Allow to take external snapshots on bs graphs node.") Signed-off-by: Markus Armbruster Message-ID: <20240306142831.2514431-1-armbru@redhat.com> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- blockdev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/blockdev.c b/blockdev.c index d8fb3399f5..057601dcf0 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1395,7 +1395,8 @@ static void external_snapshot_action(TransactionAction *action, bdrv_drained_begin(state->old_bs); if (!bdrv_is_inserted(state->old_bs)) { - error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device); + error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, + bdrv_get_device_or_node_name(state->old_bs)); return; }