nfsd4: more robust ignoring of WANT bits in OPEN

Mask out the WANT bits right at the start instead of on each use.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 4e41f65..5b192a2 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -315,6 +315,9 @@
 	if (open->op_create && open->op_claim_type != NFS4_OPEN_CLAIM_NULL)
 		return nfserr_inval;
 
+	/* We don't yet support WANT bits: */
+	open->op_share_access &= NFS4_SHARE_ACCESS_MASK;
+
 	/*
 	 * RFC5661 18.51.3
 	 * Before RECLAIM_COMPLETE done, server should deny new lock