From: Rui Wang <rui.y.wang@intel.com>
Date: Fri, 8 Jan 2016 15:09:59 +0000 (+0800)
Subject: ovl: fix getcwd() failure after unsuccessful rmdir
X-Git-Tag: firefly_0821_release~176^2~4^2~51^2~41
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=2f639e2e95ea8c06f287f768bc17d03d43480d0d;p=firefly-linux-kernel-4.4.55.git

ovl: fix getcwd() failure after unsuccessful rmdir

commit ce9113bbcbf45a57c082d6603b9a9f342be3ef74 upstream.

ovl_remove_upper() should do d_drop() only after it successfully
removes the dir, otherwise a subsequent getcwd() system call will
fail, breaking userspace programs.

This is to fix: https://bugzilla.kernel.org/show_bug.cgi?id=110491

Signed-off-by: Rui Wang <rui.y.wang@intel.com>
Reviewed-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 007e61eb2358..a2b1d7ce3e1a 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -618,7 +618,8 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
 	 * sole user of this dentry.  Too tricky...  Just unhash for
 	 * now.
 	 */
-	d_drop(dentry);
+	if (!err)
+		d_drop(dentry);
 	mutex_unlock(&dir->i_mutex);
 
 	return err;