From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:36292 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424926AbeBOPrg (ORCPT ); Thu, 15 Feb 2018 10:47:36 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Amir Goldstein , Miklos Szeredi Subject: [PATCH 4.15 195/202] ovl: take mnt_want_write() for removing impure xattr Date: Thu, 15 Feb 2018 16:18:15 +0100 Message-Id: <20180215151722.886256529@linuxfoundation.org> In-Reply-To: <20180215151712.768794354@linuxfoundation.org> References: <20180215151712.768794354@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Amir Goldstein commit a5a927a7c82e28ea76599dee4019c41e372c911f upstream. The optimization in ovl_cache_get_impure() that tries to remove an unneeded "impure" xattr needs to take mnt_want_write() on upper fs. Fixes: 4edb83bb1041 ("ovl: constant d_ino for non-merge dirs") Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/readdir.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -593,8 +593,15 @@ static struct ovl_dir_cache *ovl_cache_g return ERR_PTR(res); } if (list_empty(&cache->entries)) { - /* Good oportunity to get rid of an unnecessary "impure" flag */ - ovl_do_removexattr(ovl_dentry_upper(dentry), OVL_XATTR_IMPURE); + /* + * A good opportunity to get rid of an unneeded "impure" flag. + * Removing the "impure" xattr is best effort. + */ + if (!ovl_want_write(dentry)) { + ovl_do_removexattr(ovl_dentry_upper(dentry), + OVL_XATTR_IMPURE); + ovl_drop_write(dentry); + } ovl_clear_flag(OVL_IMPURE, d_inode(dentry)); kfree(cache); return NULL;