From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:43620 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753176AbdDJRgj (ORCPT ); Mon, 10 Apr 2017 13:36:39 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9C002A794 for ; Mon, 10 Apr 2017 17:36:33 +0000 (UTC) Received: from bfoster.bfoster (dhcp-41-20.bos.redhat.com [10.18.41.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7EF2B17145 for ; Mon, 10 Apr 2017 17:36:33 +0000 (UTC) From: Brian Foster Subject: [PATCH] xfs: drop iolock from reclaim context to appease lockdep Date: Mon, 10 Apr 2017 13:36:32 -0400 Message-Id: <1491845792-7143-1-git-send-email-bfoster@redhat.com> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs@vger.kernel.org Lockdep complains about use of the iolock in inode reclaim context because it doesn't understand that reclaim has the last reference to the inode, and thus an iolock->reclaim->iolock deadlock is not possible. The iolock is technically not necessary in xfs_inactive() and was only added to appease an assert in xfs_free_eofblocks(), which can be called from other non-reclaim contexts. Therefore, just kill the assert and drop the use of the iolock from reclaim context to quiet lockdep. Signed-off-by: Brian Foster --- fs/xfs/xfs_bmap_util.c | 8 +++----- fs/xfs/xfs_inode.c | 9 +++++---- 2 files changed, 8 insertions(+), 9 deletions(-) diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 4d1920e..de94798 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -903,9 +903,9 @@ xfs_can_free_eofblocks(struct xfs_inode *ip, bool force) } /* - * This is called by xfs_inactive to free any blocks beyond eof - * when the link count isn't zero and by xfs_dm_punch_hole() when - * punching a hole to EOF. + * This is called to free any blocks beyond eof. The caller must hold + * IOLOCK_EXCL unless we are in the inode reclaim path and have the only + * reference to the inode. */ int xfs_free_eofblocks( @@ -920,8 +920,6 @@ xfs_free_eofblocks( struct xfs_bmbt_irec imap; struct xfs_mount *mp = ip->i_mount; - ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL)); - /* * Figure out if there are any blocks beyond the end * of the file. If not, then there is nothing to do. diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 7605d83..ec9826c 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1906,12 +1906,13 @@ xfs_inactive( * force is true because we are evicting an inode from the * cache. Post-eof blocks must be freed, lest we end up with * broken free space accounting. + * + * Note: don't bother with iolock here since lockdep complains + * about acquiring it in reclaim context. We have the only + * reference to the inode at this point anyways. */ - if (xfs_can_free_eofblocks(ip, true)) { - xfs_ilock(ip, XFS_IOLOCK_EXCL); + if (xfs_can_free_eofblocks(ip, true)) xfs_free_eofblocks(ip); - xfs_iunlock(ip, XFS_IOLOCK_EXCL); - } return; } -- 2.7.4