1 files changed, 12 insertions, 15 deletions
diff --git a/test/v9fs.py b/test/v9fs.py
index fa35388f..30efe9fb 100644
--- a/test/v9fs.py
+++ b/test/v9fs.py
@@ -45,6 +45,7 @@ def worker(mountpoint, socket, uid, gid, original_namespace):
     tree = mountpoint
     assert {'os', 'index', 'pane', 'status', 'look', 'exec', 'log', 'screen', 'README'} <= set(os.listdir(tree))
     assert 'self' not in os.listdir(tree) and 'new' not in os.listdir(tree)
+    assert 'new' not in os.listdir(tree / 'pane'), 'a listing would make a pane per stat'
     # A direct connection provides independent evidence for VFS reads/writes.
     with Client(socket) as client:
         assert (tree / 'index').read_bytes() == client.read('/index')
@@ -55,26 +56,22 @@ def worker(mountpoint, socket, uid, gid, original_namespace):
         subprocess.run(['find', str(tree / 'pane'), '-ls'], check=True, capture_output=True, timeout=5)
         assert (tree / 'README').read_bytes() == client.read('/README')
         assert client.read('/index') == before, 'browsing created panes'
-        # mkdir through the kernel mount opens a pane. The editor names it
-        # after its serial, not after the name asked for, so the kernel's own
-        # revalidation of that name may fail; the index is the answer.
+        # Opening pane/new makes a pane and the read names it, so no trip
+        # through the index. Whether a repeated path reaches the server at all
+        # is the kernel's dentry cache's business, so the second pane comes
+        # over the wire, where the open is exact.
         def serials():
             return {int(row.split()[0]) for row in (tree / 'index').read_bytes().splitlines()}
 
-        def mkpane(name):
+        def mkpane():
             known = serials()
-            try:
-                (tree / 'pane' / name).mkdir()
-            except FileNotFoundError:
-                pass
-            made = serials() - known
-            assert len(made) == 1, (name, made)
-            return made.pop()
+            made = int((tree / 'pane' / 'new').read_bytes())
+            assert made not in known, 'the open of new made no pane'
+            return made
 
-        serial = mkpane('kernel-made')
-        another = mkpane('kernel-made-again')
-        assert serial != another, 'a second mkdir reused a pane'
-        assert not (tree / 'pane' / 'kernel-made').exists()
+        serial = mkpane()
+        another = int(client.read('/pane/new'))
+        assert serial != another, 'a second open of new reused a pane'
         (tree / 'pane' / str(another)).rmdir()
         assert another not in serials()
         pane = tree / 'pane' / str(serial)