nfs41: nfs41: fix state manager deadlock in session reset

If the session is reset during state recovery, the state manager thread can
sleep on the slot_tbl_waitq causing a deadlock.

Add a completion framework to the session.  Have the state manager thread set
a new session state (NFS4CLNT_SESSION_DRAINING) and wait for the session slot
table to drain.

Signal the state manager thread in nfs41_sequence_free_slot when the
NFS4CLNT_SESSION_DRAINING bit is set and the session is drained.

Reported-by: Trond Myklebust <trond@netapp.com>
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index e9ecd6bf9257..5c7740178a08 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -45,6 +45,7 @@ enum nfs4_client_state {
         NFS4CLNT_RECLAIM_NOGRACE,
         NFS4CLNT_DELEGRETURN,
         NFS4CLNT_SESSION_RESET,
+        NFS4CLNT_SESSION_DRAINING,
 };
 
 /*