Additionally, after the umount, the jbd kernel thread is still running for the block device, which is why it can't be claimed.
$ sudo ps ax | grep jbd 333 ? S 0:00 [jbd2/vda1-8] 824 ? S 0:00 [jbd2/vdb-8] ^^^^^ This shouldn't be running.
However, nothing, anywhere, *seems* to be holding it. Kernel bug?
sudo grep -h vdb /proc/*/task/*/mountinfo
gives no output.
Additionally, after the umount, the jbd kernel thread is still running for the block device, which is why it can't be claimed.
$ sudo ps ax | grep jbd
^^ ^^^
This shouldn't be running.
333 ? S 0:00 [jbd2/vda1-8]
824 ? S 0:00 [jbd2/vdb-8]
However, nothing, anywhere, *seems* to be holding it. Kernel bug?
sudo grep -h vdb /proc/* /task/* /mountinfo
gives no output.