From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id AC8A47F3F for ; Thu, 13 Mar 2014 12:10:36 -0500 (CDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay3.corp.sgi.com (Postfix) with ESMTP id 41D09AC004 for ; Thu, 13 Mar 2014 10:10:36 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id NxybemX9GaimHKyQ for ; Thu, 13 Mar 2014 10:10:32 -0700 (PDT) Subject: Re: [Cluster-devel] [PATCH] fs: push sync_filesystem() down to the file system's remount_fs() From: Steven Whitehouse In-Reply-To: <20140313162319.GA504@quack.suse.cz> References: <20140313073936.GA14663@infradead.org> <1394720456-16629-1-git-send-email-tytso@mit.edu> <20140313162319.GA504@quack.suse.cz> Date: Thu, 13 Mar 2014 16:28:23 +0000 Message-ID: <1394728103.2767.32.camel@menhir> Mime-Version: 1.0 List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Jan Kara Cc: jfs-discussion@lists.sourceforge.net, Anders Larsen , linux-mtd@lists.infradead.org, Mikulas Patocka , Petr Vandrovec , codalist@TELEMANN.coda.cs.cmu.edu, linux-cifs@vger.kernel.org, linux-fsdevel@thunk.org, cluster-devel@redhat.com, Ext4 Developers List , Evgeniy Dushistov , Kees Cook , fuse-devel@lists.sourceforge.net, reiserfs-devel@vger.kernel.org, xfs@oss.sgi.com, linux-nilfs@vger.kernel.org, OGAWA Hirofumi , linux-nfs@vger.kernel.org, Theodore Ts'o , Artem Bityutskiy , linux-ntfs-dev@lists.sourceforge.net, samba-technical@lists.samba.org, Adrian Hunter , linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Phillip Lougher , ocfs2-devel@oss.oracle.com Hi, On Thu, 2014-03-13 at 17:23 +0100, Jan Kara wrote: > On Thu 13-03-14 10:20:56, Ted Tso wrote: > > Previously, the no-op "mount -o mount /dev/xxx" operation when the > ^^remount > > > file system is already mounted read-write causes an implied, > > unconditional syncfs(). This seems pretty stupid, and it's certainly > > documented or guaraunteed to do this, nor is it particularly useful, > > except in the case where the file system was mounted rw and is getting > > remounted read-only. > > > > However, it's possible that there might be some file systems that are > > actually depending on this behavior. In most file systems, it's > > probably fine to only call sync_filesystem() when transitioning from > > read-write to read-only, and there are some file systems where this is > > not needed at all (for example, for a pseudo-filesystem or something > > like romfs). > Hum, I'd avoid this excercise at least for filesystem where > sync_filesystem() is obviously useless - proc, debugfs, pstore, devpts, > also always read-only filesystems such as isofs, qnx4, qnx6, befs, cramfs, > efs, freevxfs, romfs, squashfs. I think you can find a couple more which > clearly don't care about sync_filesystem() if you look a bit closer. > > > Honza I guess the same is true for other file systems which are mounted ro too. So maybe a check for MS_RDONLY before doing the sync in those cases? Steve. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs