From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f193.google.com ([209.85.128.193]:36723 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S968297AbdD0I73 (ORCPT ); Thu, 27 Apr 2017 04:59:29 -0400 From: Amir Goldstein To: Miklos Szeredi Cc: "Darrick J . Wong" , Christoph Hellwig , Theodore Ts'o , Jaegeuk Kim , Mark Fasheh , Al Viro , linux-xfs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 1/5] vfs: define a flag to indicate sb->s_uuid is available Date: Thu, 27 Apr 2017 11:59:30 +0300 Message-Id: <1493283574-1497-2-git-send-email-amir73il@gmail.com> In-Reply-To: <1493283574-1497-1-git-send-email-amir73il@gmail.com> References: <1493283574-1497-1-git-send-email-amir73il@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Overlayfs would like to make use of underlying filesystem's sb->s_uuid, but not all filesytems fill this field. Define a flag to be set by filesystems that do fill the s_uuid field, so let consumers like overlayfs know that the content of this field is valid. Signed-off-by: Amir Goldstein --- include/linux/fs.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/fs.h b/include/linux/fs.h index 80daadf..de913b4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1272,6 +1272,9 @@ struct mm_struct; /* sb->s_iflags to limit user namespace mounts */ #define SB_I_USERNS_VISIBLE 0x00000010 /* fstype already mounted */ +/* sb->s_iflags for optional information available in super_block struct */ +#define SB_I_HAVE_UUID 0x00000100 /* s_uuid */ + /* Possible states of 'frozen' field */ enum { SB_UNFROZEN = 0, /* FS is unfrozen */ -- 2.7.4