diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 844813a7e12a..ef76ba632387 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -279,11 +279,15 @@ do_open_lookup(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, stru
 		if (open->op_createmode == NFS4_CREATE_EXCLUSIVE && status == 0)
 			open->op_bmval[1] = (FATTR4_WORD1_TIME_ACCESS |
 							FATTR4_WORD1_TIME_MODIFY);
-	} else {
+	} else
+		/*
+		 * Note this may exit with the parent still locked.
+		 * We will hold the lock until nfsd4_open's final
+		 * lookup, to prevent renames or unlinks until we've had
+		 * a chance to an acquire a delegation if appropriate.
+		 */
 		status = nfsd_lookup(rqstp, current_fh,
 				     open->op_fname.data, open->op_fname.len, *resfh);
-		fh_unlock(current_fh);
-	}
 	if (status)
 		goto out;
 	status = nfsd_check_obj_isreg(*resfh);
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index e85b463fac4a..a41302a00650 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -207,7 +207,12 @@ nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
 				goto out_nfserr;
 		}
 	} else {
-		fh_lock(fhp);
+		/*
+		 * In the nfsd4_open() case, this may be held across
+		 * subsequent open and delegation acquisition which may
+		 * need to take the child's i_mutex:
+		 */
+		fh_lock_nested(fhp, I_MUTEX_PARENT);
 		dentry = lookup_one_len(name, dparent, len);
 		host_err = PTR_ERR(dentry);
 		if (IS_ERR(dentry))