Failing to send a CLOSE if file is opened WRONLY and server reboots on a 4.x mount

commit a41cbe86 upstream.

A test case is as the description says:
open(foobar, O_WRONLY);
sleep()  --> reboot the server
close(foobar)

The bug is because in nfs4state.c in nfs4_reclaim_open_state() a few
line before going to restart, there is
clear_bit(NFS4CLNT_RECLAIM_NOGRACE, &state->flags).

NFS4CLNT_RECLAIM_NOGRACE is a flag for the client states not open
owner states. Value of NFS4CLNT_RECLAIM_NOGRACE is 4 which is the
value of NFS_O_WRONLY_STATE in nfs4_state->flags. So clearing it wipes
out state and when we go to close it, “call_close” doesn’t get set as
state flag is not set and CLOSE doesn’t go on the wire.
Signed-off-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

fs/nfs/nfs4state.c

@@ -1482,7 +1482,7 @@ static int nfs4_reclaim_open_state(struct nfs4_state_owner *sp, const struct nfs
 					spin_unlock(&state->state_lock);
 				}
 				nfs4_put_open_state(state);
-				clear_bit(NFS4CLNT_RECLAIM_NOGRACE,
+				clear_bit(NFS_STATE_RECLAIM_NOGRACE,
 					&state->flags);
 				spin_lock(&sp->so_lock);
 				goto restart;