From 9177bcd0ba7f68bd5e28123c95fe0d69f822703e Mon Sep 17 00:00:00 2001
From: Nicolas Lacasse <nlacasse@google.com>
Date: Fri, 1 Mar 2019 11:57:52 -0800
Subject: DecRef replaced dirent in inode_overlay.

PiperOrigin-RevId: 236352158
Change-Id: Ide5104620999eaef6820917505e7299c7b0c5a03
---
 pkg/sentry/fs/inode_overlay.go | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

(limited to 'pkg/sentry/fs')

diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go
index b11e2bd13..92a77917a 100644
--- a/pkg/sentry/fs/inode_overlay.go
+++ b/pkg/sentry/fs/inode_overlay.go
@@ -336,18 +336,26 @@ func overlayRename(ctx context.Context, o *overlayEntry, oldParent *Dirent, rena
 	if err != nil && err != syserror.ENOENT {
 		return err
 	}
-	if err == nil && !replaced.IsNegative() && IsDir(replaced.Inode.StableAttr) {
-		children, err := readdirOne(ctx, replaced)
-		if err != nil {
-			return err
-		}
+	if err == nil {
+		// NOTE: We must drop the reference on replaced before we make
+		// the rename call. For that reason we can't use defer.
+		if !replaced.IsNegative() && IsDir(replaced.Inode.StableAttr) {
+			children, err := readdirOne(ctx, replaced)
+			if err != nil {
+				replaced.DecRef()
+				return err
+			}
 
-		// readdirOne ensures that "." and ".." are not
-		// included among the returned children, so we don't
-		// need to bother checking for them.
-		if len(children) > 0 {
-			return syserror.ENOTEMPTY
+			// readdirOne ensures that "." and ".." are not
+			// included among the returned children, so we don't
+			// need to bother checking for them.
+			if len(children) > 0 {
+				replaced.DecRef()
+				return syserror.ENOTEMPTY
+			}
 		}
+
+		replaced.DecRef()
 	}
 	if err := copyUpLockedForRename(ctx, renamed); err != nil {
 		return err
-- 
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