From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:46774 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932939AbdDGMCc (ORCPT ); Fri, 7 Apr 2017 08:02:32 -0400 Date: Fri, 7 Apr 2017 08:02:30 -0400 From: Brian Foster Subject: Re: [PATCH 1/3] xfs: fix up quotacheck buffer list error handling Message-ID: <20170407120229.GA54992@bfoster.bfoster> References: <1487966001-63263-1-git-send-email-bfoster@redhat.com> <1487966001-63263-2-git-send-email-bfoster@redhat.com> <20170406223921.GB4864@birch.djwong.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170406223921.GB4864@birch.djwong.org> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org, Dave Chinner , Martin Svec On Thu, Apr 06, 2017 at 03:39:21PM -0700, Darrick J. Wong wrote: > On Fri, Feb 24, 2017 at 02:53:19PM -0500, Brian Foster wrote: > > The quotacheck error handling of the delwri buffer list assumes the > > resident buffers are locked and doesn't clear the _XBF_DELWRI_Q flag > > on the buffers that are dequeued. This can lead to assert failures > > on buffer release and possibly other locking problems. > > > > Update the error handling code to lock each buffer as it is removed > > from the buffer list and clear the delwri queue flag. > > > > Signed-off-by: Brian Foster > > --- > > fs/xfs/xfs_buf.c | 2 ++ > > fs/xfs/xfs_qm.c | 2 ++ > > 2 files changed, 4 insertions(+) > > > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > > index ac3b4db..e566510 100644 > > --- a/fs/xfs/xfs_buf.c > > +++ b/fs/xfs/xfs_buf.c > > @@ -1078,6 +1078,8 @@ void > > xfs_buf_unlock( > > struct xfs_buf *bp) > > { > > + ASSERT(xfs_buf_islocked(bp)); > > + > > XB_CLEAR_OWNER(bp); > > up(&bp->b_sema); > > > > diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c > > index b669b12..4ff993c 100644 > > --- a/fs/xfs/xfs_qm.c > > +++ b/fs/xfs/xfs_qm.c > > @@ -1387,6 +1387,8 @@ xfs_qm_quotacheck( > > while (!list_empty(&buffer_list)) { > > struct xfs_buf *bp = > > list_first_entry(&buffer_list, struct xfs_buf, b_list); > > + xfs_buf_lock(bp); > > + bp->b_flags &= ~_XBF_DELWRI_Q; > > list_del_init(&bp->b_list); > > xfs_buf_relse(bp); > > Hmm, was this the only place we ever _buf_unlock'd an unlocked buffer? > I'm not aware of any other places (otherwise I would try to fix them :). Or perhaps I'm not following the question... I do recall a similar problem with flush locks fixed in commit 98efe8a ("xfs: fix unbalanced inode reclaim flush locking"). Brian > --D > > > } > > -- > > 2.7.4 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html