lockd: fix lockd shutdown race
authorJ. Bruce Fields <bfields@redhat.com>
Wed, 29 Mar 2017 01:25:08 +0000 (21:25 -0400)
committerJ. Bruce Fields <bfields@redhat.com>
Mon, 8 May 2017 22:06:18 +0000 (18:06 -0400)
commitefda760fe95ea15291853c8fa9235c32d319cd98
tree2769a42950ce9704f3a3c7b9fd9a61b4426d7d30
parented6473ddc704a2005b9900ca08e236ebb2d8540a
lockd: fix lockd shutdown race

As reported by David Jeffery: "a signal was sent to lockd while lockd
was shutting down from a request to stop nfs.  The signal causes lockd
to call restart_grace() which puts the lockd_net structure on the grace
list.  If this signal is received at the wrong time, it will occur after
lockd_down_net() has called locks_end_grace() but before
lockd_down_net() stops the lockd thread.  This leads to lockd putting
the lockd_net structure back on the grace list, then exiting without
anything removing it from the list."

So, perform the final locks_end_grace() from the the lockd thread; this
ensures it's serialized with respect to restart_grace().

Reported-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
fs/lockd/svc.c