[LU-16536] MDS umount can get stuck due to LDLM locks

Related — Thu, 29 Jun 2023 04:13:41 +0000

the scenario is the following:

rmdir is trying to unlink a striped dir
a set of LDLM locks (from different MDT) are held by MDT
number of RPCs are sent to another MDTs to destroy the objects
another MDT umounts and no reply is sent back
this MDT starts to umount, deactivate OSP#0 (corresponding RPCs are interrupted) and waiting for LDLM lock in this namespace to release
the lock is still held by the original MDT thread doing rmdir
other OSPs are still active trying to reconnect to umounted MDTs
deadlock

Whamcloud Community JIRA