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 007e61eb2358a46a9d2a19f18829942ed82f0c62..a2b1d7ce3e1aef327c498c181a624ae5874e6c6c 100644 (file)
--- 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;