From: "Darrick J. Wong" <djwong@kernel.org>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>,
ceph-devel@vger.kernel.org, Chao Yu <yuchao0@huawei.com>,
Damien Le Moal <damien.lemoal@wdc.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Jaegeuk Kim <jaegeuk@kernel.org>,
Jeff Layton <jlayton@kernel.org>,
Johannes Thumshirn <jth@kernel.org>,
linux-cifs@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net, linux-mm@kvack.org,
linux-xfs@vger.kernel.org, Miklos Szeredi <miklos@szeredi.hu>,
Steve French <sfrench@samba.org>, Ted Tso <tytso@mit.edu>,
Matthew Wilcox <willy@infradead.org>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 07/13] xfs: Convert to use invalidate_lock
Date: Wed, 26 May 2021 08:32:51 -0700 [thread overview]
Message-ID: <20210526153251.GZ202121@locust> (raw)
In-Reply-To: <20210526101840.GC30369@quack2.suse.cz>
On Wed, May 26, 2021 at 12:18:40PM +0200, Jan Kara wrote:
> On Tue 25-05-21 14:37:29, Darrick J. Wong wrote:
> > On Tue, May 25, 2021 at 03:50:44PM +0200, Jan Kara wrote:
> > > Use invalidate_lock instead of XFS internal i_mmap_lock. The intended
> > > purpose of invalidate_lock is exactly the same. Note that the locking in
> > > __xfs_filemap_fault() slightly changes as filemap_fault() already takes
> > > invalidate_lock.
> > >
> > > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > > CC: <linux-xfs@vger.kernel.org>
> > > CC: "Darrick J. Wong" <darrick.wong@oracle.com>
> >
> > It's djwong@kernel.org now.
>
> OK, updated.
>
> > > @@ -355,8 +358,11 @@ xfs_isilocked(
> > >
> > > if (lock_flags & (XFS_MMAPLOCK_EXCL|XFS_MMAPLOCK_SHARED)) {
> > > if (!(lock_flags & XFS_MMAPLOCK_SHARED))
> > > - return !!ip->i_mmaplock.mr_writer;
> > > - return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
> > > + return !debug_locks ||
> > > + lockdep_is_held_type(
> > > + &VFS_I(ip)->i_mapping->invalidate_lock,
> > > + 0);
> > > + return rwsem_is_locked(&VFS_I(ip)->i_mapping->invalidate_lock);
> >
> > This doesn't look right...
> >
> > If lockdep is disabled, we always return true for
> > xfs_isilocked(ip, XFS_MMAPLOCK_EXCL) even if nobody holds the lock?
> >
> > Granted, you probably just copy-pasted from the IOLOCK_SHARED clause
> > beneath it. Er... oh right, preichl was messing with all that...
> >
> > https://lore.kernel.org/linux-xfs/20201016021005.548850-2-preichl@redhat.com/
>
> Indeed copy-paste programming ;) It certainly makes the assertions happy
> but useless. Should I pull the patch you reference into the series? It
> seems to have been uncontroversial and reviewed. Or will you pull the
> series to xfs tree so I can just rebase on top?
The full conversion series introduced assertion failures because lockdep
can't handle some of the ILOCK usage patterns, specifically the fact
that a thread sometimes takes the ILOCK but then hands the inode to a
workqueue to avoid overflowing the first thread's stack. That's why it
never got merged into the xfs tree.
However, that kind of switcheroo isn't done with the
MMAPLOCK/invalidate_lock, so you could simply pull the patch I linked
above into your series.
--D
>
> Honza
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
next prev parent reply other threads:[~2021-05-26 15:32 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-25 13:50 [PATCH 0/13 v6] fs: Hole punch vs page cache filling races Jan Kara
2021-05-25 13:50 ` [PATCH 01/13] mm: Fix comments mentioning i_mutex Jan Kara
2021-05-25 13:50 ` [PATCH 02/13] documentation: Sync file_operations members with reality Jan Kara
2021-05-25 20:43 ` Darrick J. Wong
2021-05-25 13:50 ` [PATCH 03/13] mm: Protect operations adding pages to page cache with invalidate_lock Jan Kara
2021-05-25 21:01 ` Darrick J. Wong
2021-05-26 10:00 ` Jan Kara
2021-05-25 13:50 ` [PATCH 04/13] mm: Add functions to lock invalidate_lock for two mappings Jan Kara
2021-05-25 20:48 ` Darrick J. Wong
2021-05-26 10:07 ` Jan Kara
2021-05-26 12:11 ` Damien Le Moal
2021-05-26 13:45 ` Jan Kara
2021-05-26 15:25 ` Darrick J. Wong
2021-05-25 13:50 ` [PATCH 05/13] ext4: Convert to use mapping->invalidate_lock Jan Kara
2021-05-25 13:50 ` [PATCH 06/13] ext2: Convert to using invalidate_lock Jan Kara
2021-05-25 13:50 ` [PATCH 07/13] xfs: Convert to use invalidate_lock Jan Kara
2021-05-25 21:37 ` Darrick J. Wong
2021-05-26 10:18 ` Jan Kara
2021-05-26 15:32 ` Darrick J. Wong [this message]
2021-05-27 12:01 ` Jan Kara
2021-05-25 21:40 ` Dave Chinner
2021-05-26 10:20 ` Jan Kara
2021-05-26 13:42 ` Jan Kara
2021-05-25 13:50 ` [PATCH 08/13] xfs: Convert double locking of MMAPLOCK to use VFS helpers Jan Kara
2021-05-25 21:41 ` Darrick J. Wong
2021-05-25 13:50 ` [PATCH 09/13] zonefs: Convert to using invalidate_lock Jan Kara
2021-05-25 13:50 ` [PATCH 10/13] f2fs: " Jan Kara
2021-05-26 9:55 ` Chao Yu
2021-05-25 13:50 ` [PATCH 11/13] fuse: " Jan Kara
2021-05-25 13:50 ` [PATCH 12/13] ceph: Fix race between hole punch and page fault Jan Kara
2021-05-25 13:50 ` [PATCH 13/13] cifs: " Jan Kara
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