From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2130.oracle.com ([156.151.31.86]:53358 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933674AbeFGOxX (ORCPT ); Thu, 7 Jun 2018 10:53:23 -0400 Date: Thu, 7 Jun 2018 07:53:18 -0700 From: "Darrick J. Wong" Subject: Re: [PATCH 1/2] xfs: setup VFS i_rwsem lockdep state correctly Message-ID: <20180607145318.GE25007@magnolia> References: <20180607052132.6207-1-david@fromorbit.com> <20180607052132.6207-2-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180607052132.6207-2-david@fromorbit.com> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: linux-xfs@vger.kernel.org On Thu, Jun 07, 2018 at 03:21:31PM +1000, Dave Chinner wrote: > From: Dave Chinner > > When lockdep is enabled, it changes the type of the inode i_rwsem > semaphore before unlocking a newly instantiated inode. THere is the > possibility that there is already a waiter on that inode lock by the > time we unlock the new inode, so having lockdep re-initialise the > lock is a vector for trouble. > > Avoid this whole situation by setting up the i_rwsem lockdep class > at the same time we set up the XFS inode i_ilock classes and so the > VFS doesn't have to change the lock class itself when it is > potentially unsafe. > > Signed-Off-By: Dave Chinner With the commit message changes added, Reviewed-by: Darrick J. Wong --D > --- > fs/xfs/xfs_iops.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c > index 29484091c0d2..3020c57fc125 100644 > --- a/fs/xfs/xfs_iops.c > +++ b/fs/xfs/xfs_iops.c > @@ -1258,6 +1258,14 @@ xfs_setup_inode( > xfs_diflags_to_iflags(inode, ip); > > if (S_ISDIR(inode->i_mode)) { > + /* > + * We set the i_rwsem class here to avoid potential races with > + * lockdep_annotate_inode_mutex_key() reinitialising the lock > + * after a filehandle lookup has already found the inode in > + * cache before it has been unlocked via unlock_new_inode(). > + */ > + lockdep_set_class(&inode->i_rwsem, > + &inode->i_sb->s_type->i_mutex_dir_key); > lockdep_set_class(&ip->i_lock.mr_lock, &xfs_dir_ilock_class); > ip->d_ops = ip->i_mount->m_dir_inode_ops; > } else { > -- > 2.17.0 > > -- > 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