NFSv4: Don't try to CLOSE if the stateid 'other' field has changed

If the stateid is no longer recognised on the server, either due to a
restart, or due to a competing CLOSE call, then we do not have to
retry. Any open contexts that triggered a reopen of the file, will
also act as triggers for any CLOSE for the updated stateids.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index cee1e00..b6a0cf7 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1002,18 +1002,23 @@ bool nfs4_refresh_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
 	return ret;
 }
 
-static void nfs4_copy_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
+bool nfs4_copy_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
 {
+	bool ret;
 	const nfs4_stateid *src;
 	int seq;
 
 	do {
+		ret = false;
 		src = &zero_stateid;
 		seq = read_seqbegin(&state->seqlock);
-		if (test_bit(NFS_OPEN_STATE, &state->flags))
+		if (test_bit(NFS_OPEN_STATE, &state->flags)) {
 			src = &state->open_stateid;
+			ret = true;
+		}
 		nfs4_stateid_copy(dst, src);
 	} while (read_seqretry(&state->seqlock, seq));
+	return ret;
 }
 
 /*