Index: lib/libc/sys/open.2
===================================================================
--- lib/libc/sys/open.2
+++ lib/libc/sys/open.2
@@ -419,6 +419,11 @@
 .It Bq Er EISDIR
 The named file is a directory, and the arguments specify
 it is to be modified.
+.It Bq Er EISDIR
+The named file is a directory, and the flags specified
+.Dv O_CREAT
+without
+.Dv O_DIRECTORY .
 .It Bq Er EROFS
 The named file resides on a read-only file system,
 and the file is to be modified.
Index: sys/kern/vfs_vnops.c
===================================================================
--- sys/kern/vfs_vnops.c
+++ sys/kern/vfs_vnops.c
@@ -343,14 +343,17 @@
 		return (EMLINK);
 	if (vp->v_type == VSOCK)
 		return (EOPNOTSUPP);
-	if (vp->v_type != VDIR && fmode & O_DIRECTORY)
-		return (ENOTDIR);
-	accmode = 0;
-	if (fmode & (FWRITE | O_TRUNC)) {
-		if (vp->v_type == VDIR)
+	if (vp->v_type == VDIR) {
+		if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT ||
+		    (fmode & (FWRITE | O_TRUNC)) != 0)
 			return (EISDIR);
-		accmode |= VWRITE;
+	} else {
+		if ((fmode & O_DIRECTORY) != 0)
+			return (ENOTDIR);
 	}
+	accmode = 0;
+	if ((fmode & (FWRITE | O_TRUNC)) != 0)
+		accmode |= VWRITE;
 	if (fmode & FREAD)
 		accmode |= VREAD;
 	if (fmode & FEXEC)