nfsd41: refactor nfsd4_deleg_xgrade_none_ext logic out of nfsd4_process_open2

Handle the case where the nfsv4.1 client asked to uprade or downgrade
its delegations and server returns no delegation.

In this case, op_delegate_type is set to NFS4_OPEN_DELEGATE_NONE_EXT
and op_why_no_deleg is set respectively to WND4_NOT_SUPP_{UP,DOWN}GRADE
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -2951,6 +2951,24 @@ nfs4_open_delegation(struct svc_fh *fh, struct nfsd4_open *open, struct nfs4_ol_
 	goto out;
 }
 
+static void nfsd4_deleg_xgrade_none_ext(struct nfsd4_open *open,
+					struct nfs4_delegation *dp)
+{
+	if (open->op_deleg_want == NFS4_SHARE_WANT_READ_DELEG &&
+	    dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
+		open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+		open->op_why_no_deleg = WND4_NOT_SUPP_DOWNGRADE;
+	} else if (open->op_deleg_want == NFS4_SHARE_WANT_WRITE_DELEG &&
+		   dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
+		open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
+		open->op_why_no_deleg = WND4_NOT_SUPP_UPGRADE;
+	}
+	/* Otherwise the client must be confused wanting a delegation
+	 * it already has, therefore we don't return
+	 * NFS4_OPEN_DELEGATE_NONE_EXT and reason.
+	 */
+}
+
 /*
  * called with nfs4_lock_state() held.
  */
@@ -3035,21 +3053,8 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 out:
 	/* 4.1 client trying to upgrade/downgrade delegation? */
 	if (open->op_delegate_type == NFS4_OPEN_DELEGATE_NONE && dp &&
-	    open->op_deleg_want) {
-		if (open->op_deleg_want == NFS4_SHARE_WANT_READ_DELEG &&
-		    dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
-			open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
-			open->op_why_no_deleg = WND4_NOT_SUPP_DOWNGRADE;
-		} else if (open->op_deleg_want == NFS4_SHARE_WANT_WRITE_DELEG &&
-			   dp->dl_type == NFS4_OPEN_DELEGATE_WRITE) {
-			open->op_delegate_type = NFS4_OPEN_DELEGATE_NONE_EXT;
-			open->op_why_no_deleg = WND4_NOT_SUPP_UPGRADE;
-		}
-		/* Otherwise the client must be confused wanting a delegation
-		 * it already has, therefore we don't return
-		 * NFS4_OPEN_DELEGATE_NONE_EXT and reason.
-		 */
-	}
+	    open->op_deleg_want)
+		nfsd4_deleg_xgrade_none_ext(open, dp);
 
 	if (fp)
 		put_nfs4_file(fp);