When block_resize() runs into an op blocker, it creates an error like
this:
error_setg(errp, "Device '%s' is in use", device);
Trouble is @device can be null. My system formats null as "(null)",
but other systems might crash. Reproducer:
1. Create two block devices
-> {"execute": "blockdev-add", "arguments": {"driver": "file", "node-name": "blk0",
"filename": "64k.img"}}
<- {"return": {}}
-> {"execute": "blockdev-add", "arguments": {"driver": "file", "node-name": "blk1",
"filename": "m.img"}}
<- {"return": {}}
2. Put a blocker on one them
-> {"execute": "blockdev-mirror", "arguments": {"job-id": "job0", "device": "blk0", "target":
"blk1", "sync": "full"}}
{"return": {}}
-> {"execute": "job-pause", "arguments": {"id": "job0"}}
{"return": {}}
-> {"execute": "job-complete", "arguments": {"id": "job0"}}
{"return": {}}
Note: job events elided for brevity.
3. Attempt to resize
-> {"execute": "block_resize", "arguments": {"node-name": "blk1",
"size":32768}}
<- {"error": {"class": "GenericError", "desc": "Device '(null)' is in
use"}}
Broken when commit 3b1dbd11a60 made @device optional. Fixed in commit
ed3d2ec98a3 (block: Add errp to b{lk,drv}_truncate()), except for this
one instance.
Fix it by using the error message provided by the op blocker instead,
so it fails like this:
<- {"error": {"class": "GenericError", "desc": "Node 'blk1' is busy: block
device is in use by block job: mirror"}}
Fixes: 3b1dbd11a60d (qmp: Allow block_resize to manipulate bs graph nodes.)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
blockdev.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)