From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79CD8C43331 for ; Fri, 27 Mar 2020 17:04:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42276206F2 for ; Fri, 27 Mar 2020 17:04:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Dwr507Ri" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726900AbgC0REU (ORCPT ); Fri, 27 Mar 2020 13:04:20 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:36214 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727505AbgC0REU (ORCPT ); Fri, 27 Mar 2020 13:04:20 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 02RGrUNE167836; Fri, 27 Mar 2020 17:04:17 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=GU0Jlruv8D9TKXQVhQKN/vLVPWum+Pp/LOAE2Kug8Jg=; b=Dwr507RivKmOljoe4/a/QZWMWLX3/mcaKj1WSjT6ihy6HPKH6frLE78zagNEdSh/ovr1 Rq9QOjHS9/kfyvRmJIwHqKTJXxfL1zdeyRxtpUKxTqqI++9xsrtk89dqbPvBX9j1uFyu a/saC2a+vMOJ+dG5pDE15ZNfo8GYfASNk6O/uyZG8YJmejoksfS5ciQUdG9NM2ds/Zp5 HUGBZEZ60/Mj2+YrtlqDdk5AauNL9sLhGeQ0j5R5DI9ZkUYh02DxS2RcEdc7qJ4YKFvN dRcOgpozlHeADSaw3BaFaY4v1GC2ZQ4RaYHvO8tySOupUXIHa/wn48L4FU4+TnYwf1Sz 6g== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 301459c9cr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 27 Mar 2020 17:04:16 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 02RGqFsU139427; Fri, 27 Mar 2020 17:04:16 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 3006ramfeq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 27 Mar 2020 17:04:16 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 02RH4EDi008329; Fri, 27 Mar 2020 17:04:15 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 27 Mar 2020 10:04:14 -0700 Date: Fri, 27 Mar 2020 10:04:13 -0700 From: "Darrick J. Wong" To: Brian Foster Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 1/2] xfs: trylock underlying buffer on dquot flush Message-ID: <20200327170413.GL29339@magnolia> References: <20200326131703.23246-1-bfoster@redhat.com> <20200326131703.23246-2-bfoster@redhat.com> <20200327154527.GJ29339@magnolia> <20200327164440.GB29156@bfoster> <20200327164644.GC29156@bfoster> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200327164644.GC29156@bfoster> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9573 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 adultscore=0 suspectscore=0 phishscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003270146 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9573 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 phishscore=0 priorityscore=1501 bulkscore=0 lowpriorityscore=0 mlxlogscore=999 adultscore=0 suspectscore=0 impostorscore=0 mlxscore=0 spamscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003270146 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Mar 27, 2020 at 12:46:44PM -0400, Brian Foster wrote: > On Fri, Mar 27, 2020 at 12:44:40PM -0400, Brian Foster wrote: > > On Fri, Mar 27, 2020 at 08:45:28AM -0700, Darrick J. Wong wrote: > > > On Thu, Mar 26, 2020 at 09:17:02AM -0400, Brian Foster wrote: > > > > A dquot flush currently blocks on the buffer lock for the underlying > > > > dquot buffer. In turn, this causes xfsaild to block rather than > > > > continue processing other items in the meantime. Update > > > > xfs_qm_dqflush() to trylock the buffer, similar to how inode buffers > > > > are handled, and return -EAGAIN if the lock fails. Fix up any > > > > callers that don't currently handle the error properly. > > > > > > > > Signed-off-by: Brian Foster > > > > > > Is xfs_qm_dquot_isolate returning LRU_RETRY an acceptable resolution (as > > > opposed to, say, LRU_SKIP) for xfs_qm_dqflush returning -EAGAIN? > > > > > > > Hmm.. this is reclaim so I suppose LRU_SKIP would be more appropriate > > than retry (along with more consistent with the other trylock failures > > in that function). Ok with something like the following? > > > > @@ -461,7 +461,11 @@ xfs_qm_dquot_isolate( > > spin_unlock(lru_lock); > > > > error = xfs_qm_dqflush(dqp, &bp); > > - if (error) > > + if (error == -EAGAIN) { > > + xfs_dqunlock(dqp); > > + spin_lock(lru_lock); > > + goto out_miss_busy; > > + } else if (error) > > goto out_unlock_dirty; > > Then again, is it safe to skip from here once we've cycled the lru_lock? DOH. Yeah, I missed that we cycled the lru lock and therefore have to LRU_RETRY. So I guess the original patch was fine: Reviewed-by: Darrick J. Wong --D > Brian > > > > > xfs_buf_delwri_queue(bp, &isol->buffers); > > > > Brian > > > > > --D > > > > > > > --- > > > > fs/xfs/xfs_dquot.c | 6 +++--- > > > > fs/xfs/xfs_dquot_item.c | 3 ++- > > > > fs/xfs/xfs_qm.c | 14 +++++++++----- > > > > 3 files changed, 14 insertions(+), 9 deletions(-) > > > > > > > > diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c > > > > index 711376ca269f..af2c8e5ceea0 100644 > > > > --- a/fs/xfs/xfs_dquot.c > > > > +++ b/fs/xfs/xfs_dquot.c > > > > @@ -1105,8 +1105,8 @@ xfs_qm_dqflush( > > > > * Get the buffer containing the on-disk dquot > > > > */ > > > > error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno, > > > > - mp->m_quotainfo->qi_dqchunklen, 0, &bp, > > > > - &xfs_dquot_buf_ops); > > > > + mp->m_quotainfo->qi_dqchunklen, XBF_TRYLOCK, > > > > + &bp, &xfs_dquot_buf_ops); > > > > if (error) > > > > goto out_unlock; > > > > > > > > @@ -1177,7 +1177,7 @@ xfs_qm_dqflush( > > > > > > > > out_unlock: > > > > xfs_dqfunlock(dqp); > > > > - return -EIO; > > > > + return error; > > > > } > > > > > > > > /* > > > > diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c > > > > index cf65e2e43c6e..baad1748d0d1 100644 > > > > --- a/fs/xfs/xfs_dquot_item.c > > > > +++ b/fs/xfs/xfs_dquot_item.c > > > > @@ -189,7 +189,8 @@ xfs_qm_dquot_logitem_push( > > > > if (!xfs_buf_delwri_queue(bp, buffer_list)) > > > > rval = XFS_ITEM_FLUSHING; > > > > xfs_buf_relse(bp); > > > > - } > > > > + } else if (error == -EAGAIN) > > > > + rval = XFS_ITEM_LOCKED; > > > > > > > > spin_lock(&lip->li_ailp->ail_lock); > > > > out_unlock: > > > > diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c > > > > index de1d2c606c14..68c778d25c48 100644 > > > > --- a/fs/xfs/xfs_qm.c > > > > +++ b/fs/xfs/xfs_qm.c > > > > @@ -121,12 +121,11 @@ xfs_qm_dqpurge( > > > > { > > > > struct xfs_mount *mp = dqp->q_mount; > > > > struct xfs_quotainfo *qi = mp->m_quotainfo; > > > > + int error = -EAGAIN; > > > > > > > > xfs_dqlock(dqp); > > > > - if ((dqp->dq_flags & XFS_DQ_FREEING) || dqp->q_nrefs != 0) { > > > > - xfs_dqunlock(dqp); > > > > - return -EAGAIN; > > > > - } > > > > + if ((dqp->dq_flags & XFS_DQ_FREEING) || dqp->q_nrefs != 0) > > > > + goto out_unlock; > > > > > > > > dqp->dq_flags |= XFS_DQ_FREEING; > > > > > > > > @@ -139,7 +138,6 @@ xfs_qm_dqpurge( > > > > */ > > > > if (XFS_DQ_IS_DIRTY(dqp)) { > > > > struct xfs_buf *bp = NULL; > > > > - int error; > > > > > > > > /* > > > > * We don't care about getting disk errors here. We need > > > > @@ -149,6 +147,8 @@ xfs_qm_dqpurge( > > > > if (!error) { > > > > error = xfs_bwrite(bp); > > > > xfs_buf_relse(bp); > > > > + } else if (error == -EAGAIN) { > > > > + goto out_unlock; > > > > } > > > > xfs_dqflock(dqp); > > > > } > > > > @@ -174,6 +174,10 @@ xfs_qm_dqpurge( > > > > > > > > xfs_qm_dqdestroy(dqp); > > > > return 0; > > > > + > > > > +out_unlock: > > > > + xfs_dqunlock(dqp); > > > > + return error; > > > > } > > > > > > > > /* > > > > -- > > > > 2.21.1 > > > > > > > > > >