From f40d023ad6f8c19898ca105842a88961b3c2994c Mon Sep 17 00:00:00 2001
From: Dean Deng <deandeng@google.com>
Date: Fri, 19 Jun 2020 08:44:26 -0700
Subject: [PATCH] Don't adjust parent link count if we replace a child dir with
 another.

Updates #2923.

PiperOrigin-RevId: 317314460
---
 pkg/sentry/fsimpl/gofer/filesystem.go | 3 ++-
 test/syscalls/BUILD                   | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go
index 21eb976cb..5501781ac 100644
--- a/pkg/sentry/fsimpl/gofer/filesystem.go
+++ b/pkg/sentry/fsimpl/gofer/filesystem.go
@@ -1196,7 +1196,8 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
 	if newParent.cachedMetadataAuthoritative() {
 		newParent.dirents = nil
 		newParent.touchCMtime()
-		if renamed.isDir() {
+		if renamed.isDir() && (replaced == nil || !replaced.isDir()) {
+			// Increase the link count if we did not replace another directory.
 			newParent.incLinks()
 		}
 	}
diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD
index 7b0248a39..131f09ab4 100644
--- a/test/syscalls/BUILD
+++ b/test/syscalls/BUILD
@@ -572,6 +572,7 @@ syscall_test(
     size = "medium",
     add_overlay = True,
     test = "//test/syscalls/linux:rename_test",
+    vfs2 = "True",
 )
 
 syscall_test(