From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id 0215B7F37 for ; Sun, 23 Jun 2013 12:27:39 -0500 (CDT) Message-ID: <51C7300A.10308@sgi.com> Date: Sun, 23 Jun 2013 12:27:38 -0500 From: Mark Tinguely MIME-Version: 1.0 Subject: Re: [PATCH 08/60] xfs: Introduce an ordered buffer item References: <1371617468-32559-1-git-send-email-david@fromorbit.com> <1371617468-32559-9-git-send-email-david@fromorbit.com> In-Reply-To: <1371617468-32559-9-git-send-email-david@fromorbit.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: xfs@oss.sgi.com On 06/18/13 23:50, Dave Chinner wrote: > If we have a buffer that we have modified but we do not wish to > physically log in a transaction (e.g. we've logged a logical > change), we still need to ensure that transactional integrity is > maintained. Hence we must not move the tail of the log past the > transaction that the buffer is associated with before the buffer is > written to disk. > > This means these special buffers still need to be included in the > transaction and added to the AIL just like a normal buffer, but we > do not want the modifications to the buffer written into the > transaction. IOWs, what we want is an "ordered buffer" that > maintains the same transactional life cycle as a physically logged > buffer, just without the transcribing of the modifications to the > log. > > Hence we need to flag the buffer as an "ordered buffer" to avoid > including it in vector size calculations or formatting during the > transaction. Once the transaction is committed, the buffer appears > for all intents to be the same as a physically logged buffer as it > transitions through the log and AIL. > > Relogging will also work just fine for such an ordered buffer - the > logical transaction will be replayed before the subsequent > modifications that relog the buffer, so everything will be > reconstructed correctly by recovery. > > Signed-off-by: Dave Chinner > --- Looks good. Reviewed-by: Mark Tinguely _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs