From: Dave Chinner <david@fromorbit.com>
To: CAI Qian <caiqian@redhat.com>
Cc: linux-xfs <linux-xfs@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
xfs@oss.sgi.com
Subject: Re: xfs_file_splice_read: possible circular locking dependency detected
Date: Fri, 9 Sep 2016 07:19:31 +1000 [thread overview]
Message-ID: <20160908211931.GX30056@dastard> (raw)
In-Reply-To: <268523885.1013251.1473367174650.JavaMail.zimbra@redhat.com>
On Thu, Sep 08, 2016 at 04:39:34PM -0400, CAI Qian wrote:
>
>
> ----- Original Message -----
> > From: "Linus Torvalds" <torvalds@linux-foundation.org>
> > To: "CAI Qian" <caiqian@redhat.com>
> > Cc: "Dave Chinner" <david@fromorbit.com>, "Al Viro" <viro@zeniv.linux.org.uk>, "linux-xfs"
> > <linux-xfs@vger.kernel.org>, xfs@oss.sgi.com
> > Sent: Thursday, September 8, 2016 2:01:23 PM
> > Subject: Re: xfs_file_splice_read: possible circular locking dependency detected
> >
> > On Thu, Sep 8, 2016 at 8:29 AM, CAI Qian <caiqian@redhat.com> wrote:
> > > Right. FYI, revert the commit below fixes the regression,
> > >
> > > 8d02076 : ->splice_write() via ->write_iter()
> >
> > I guess you didn't actually revert that, because so much else has
> > changed. So you just tested the pre- and post- state of that commit?
> Right, I just reverted that commit while that one is as a HEAD. It is
> not going to be a straight-forward revert. There have had a few commits
> on the top already, so there will be some additional work to bake a proper
> revert to the current origin HEAD.
>
> Though, Everything else looks straigtforward (PAGE_CACHE_* conversion,
> inode_lock* conversion, file_remove_privs() converstion). It seems only
> tricky thing is that generic_write_sync() starts to use struct kiocb *
> instead of struct file *, so generic_file_splice_write() and probably
> xfs_file_splice_write() need to change to use kiocb as well.
Don't bother. You'll just hit a different lockdep issue - a locking
order problem on the write side. I tried to get that fixed years
ago:
https://lkml.org/lkml/2011/7/18/4
http://oss.sgi.com/archives/xfs/2011-08/msg00122.html
http://oss.sgi.com/archives/xfs/2012-11/msg00671.html
That specific problem was fixed by the above write_iter
infrastructure fixes, but introduced the read side problem. i.e.
splice has /always/ had locking order issues that XFS exposed.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
_______________________________________________
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xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2016-09-08 21:19 UTC|newest]
Thread overview: 135+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <723420070.1340881.1472835555274.JavaMail.zimbra@redhat.com>
[not found] ` <1832555471.1341372.1472835736236.JavaMail.zimbra@redhat.com>
2016-09-03 0:39 ` xfs_file_splice_read: possible circular locking dependency detected Dave Chinner
2016-09-03 0:57 ` Linus Torvalds
2016-09-03 1:45 ` Al Viro
2016-09-06 23:59 ` Dave Chinner
2016-09-08 20:35 ` Al Viro
2016-09-06 21:53 ` CAI Qian
2016-09-06 23:34 ` Dave Chinner
2016-09-08 15:29 ` CAI Qian
2016-09-08 17:56 ` Al Viro
2016-09-08 18:12 ` Linus Torvalds
2016-09-08 18:18 ` Linus Torvalds
2016-09-08 20:44 ` Al Viro
2016-09-08 20:57 ` Al Viro
2016-09-08 21:23 ` Al Viro
2016-09-08 21:38 ` Dave Chinner
2016-09-08 23:55 ` Al Viro
2016-09-09 1:53 ` Dave Chinner
2016-09-09 2:22 ` Linus Torvalds
2016-09-09 2:26 ` Linus Torvalds
2016-09-09 2:34 ` Al Viro
2016-09-09 2:50 ` Linus Torvalds
2016-09-09 22:19 ` Al Viro
2016-09-10 2:06 ` Linus Torvalds
2016-09-14 3:16 ` Al Viro
2016-09-14 3:39 ` Nicholas Piggin
2016-09-14 4:01 ` Linus Torvalds
2016-09-18 5:33 ` Al Viro
2016-09-19 3:08 ` Nicholas Piggin
2016-09-19 6:11 ` Al Viro
2016-09-19 7:26 ` Nicholas Piggin
2016-09-14 3:49 ` Linus Torvalds
2016-09-14 4:26 ` Al Viro
2016-09-17 8:20 ` Al Viro
2016-09-17 19:00 ` Al Viro
2016-09-17 20:15 ` Linus Torvalds
2016-09-23 19:00 ` [RFC][CFT] splice_read reworked Al Viro
2016-09-23 19:01 ` [PATCH 01/11] fix memory leaks in tracing_buffers_splice_read() Al Viro
2016-09-23 19:02 ` [PATCH 02/11] splice_to_pipe(): don't open-code wakeup_pipe_readers() Al Viro
2016-09-23 19:02 ` [PATCH 03/11] splice: switch get_iovec_page_array() to iov_iter Al Viro
2016-09-23 19:03 ` [PATCH 04/11] splice: lift pipe_lock out of splice_to_pipe() Al Viro
2016-09-23 19:45 ` Linus Torvalds
2016-09-23 20:10 ` Al Viro
2016-09-23 20:36 ` Linus Torvalds
2016-09-24 3:59 ` Al Viro
2016-09-24 17:29 ` Al Viro
2016-09-27 15:38 ` Nicholas Piggin
2016-09-27 15:53 ` Chuck Lever
2016-09-24 3:59 ` [PATCH 04/12] " Al Viro
2016-09-26 13:35 ` Miklos Szeredi
2016-09-27 4:14 ` Al Viro
2016-12-17 19:54 ` Andreas Schwab
2016-12-18 19:28 ` Linus Torvalds
2016-12-18 19:57 ` Andreas Schwab
2016-12-18 20:12 ` Al Viro
2016-12-18 20:30 ` Al Viro
2016-12-18 22:10 ` Linus Torvalds
2016-12-18 22:18 ` Al Viro
2016-12-18 22:22 ` Linus Torvalds
2016-12-18 22:49 ` Andreas Schwab
2016-12-21 18:56 ` Andreas Schwab
2016-12-21 19:12 ` Linus Torvalds
2016-09-24 4:00 ` [PATCH 06/12] new helper: add_to_pipe() Al Viro
2016-09-26 13:49 ` Miklos Szeredi
2016-09-24 4:01 ` [PATCH 10/12] new iov_iter flavour: pipe-backed Al Viro
2016-09-29 20:53 ` Miklos Szeredi
2016-09-29 22:50 ` Al Viro
2016-09-30 7:30 ` Miklos Szeredi
2016-10-03 3:34 ` [RFC] O_DIRECT vs EFAULT (was Re: [PATCH 10/12] new iov_iter flavour: pipe-backed) Al Viro
2016-10-03 17:07 ` Linus Torvalds
2016-10-03 18:54 ` Al Viro
2016-09-24 4:01 ` [PATCH 11/12] switch generic_file_splice_read() to use of ->read_iter() Al Viro
2016-09-24 4:02 ` [PATCH 12/12] switch default_file_splice_read() to use of pipe-backed iov_iter Al Viro
2016-09-23 19:03 ` [PATCH 05/11] skb_splice_bits(): get rid of callback Al Viro
2016-09-23 19:04 ` [PATCH 06/11] new helper: add_to_pipe() Al Viro
2016-09-23 19:04 ` [PATCH 07/11] fuse_dev_splice_read(): switch to add_to_pipe() Al Viro
2016-09-23 19:06 ` [PATCH 08/11] cifs: don't use memcpy() to copy struct iov_iter Al Viro
2016-09-23 19:08 ` [PATCH 09/11] fuse_ioctl_copy_user(): don't open-code copy_page_{to,from}_iter() Al Viro
2016-09-26 9:31 ` Miklos Szeredi
2016-09-23 19:09 ` [PATCH 10/11] new iov_iter flavour: pipe-backed Al Viro
2016-09-23 19:10 ` [PATCH 11/11] switch generic_file_splice_read() to use of ->read_iter() Al Viro
2016-09-30 13:32 ` [RFC][CFT] splice_read reworked CAI Qian
2016-09-30 17:42 ` CAI Qian
2016-09-30 18:33 ` CAI Qian
2016-10-03 1:37 ` Al Viro
2016-10-03 17:49 ` CAI Qian
2016-10-04 17:39 ` local DoS - systemd hang or timeout (WAS: Re: [RFC][CFT] splice_read reworked) CAI Qian
2016-10-04 21:42 ` tj
2016-10-05 14:09 ` CAI Qian
2016-10-05 15:30 ` tj
2016-10-05 15:54 ` CAI Qian
2016-10-05 18:57 ` CAI Qian
2016-10-05 20:05 ` Al Viro
2016-10-06 12:20 ` CAI Qian
2016-10-06 12:25 ` CAI Qian
2016-10-06 16:11 ` CAI Qian
2016-10-06 17:00 ` Linus Torvalds
2016-10-06 18:12 ` CAI Qian
2016-10-07 9:57 ` Dave Chinner
2016-10-07 15:25 ` Linus Torvalds
2016-10-07 7:08 ` Jan Kara
2016-10-07 14:43 ` CAI Qian
2016-10-07 15:27 ` CAI Qian
2016-10-07 18:56 ` CAI Qian
2016-10-09 21:54 ` Dave Chinner
2016-10-10 14:10 ` CAI Qian
2016-10-10 20:14 ` CAI Qian
2016-10-10 21:57 ` Dave Chinner
2016-10-12 19:50 ` [bisected] " CAI Qian
2016-10-12 20:59 ` Dave Chinner
2016-10-13 16:25 ` CAI Qian
2016-10-13 20:49 ` Dave Chinner
2016-10-13 20:56 ` CAI Qian
2016-10-09 21:51 ` Dave Chinner
2016-10-07 9:27 ` Dave Chinner
2016-10-03 1:42 ` [RFC][CFT] splice_read reworked Al Viro
2016-10-03 14:06 ` CAI Qian
2016-10-03 15:20 ` CAI Qian
2016-10-03 21:12 ` Dave Chinner
2016-10-04 13:57 ` CAI Qian
2016-10-03 20:32 ` CAI Qian
2016-10-03 20:35 ` Al Viro
2016-10-04 13:29 ` CAI Qian
2016-10-04 14:28 ` Al Viro
2016-10-04 16:21 ` CAI Qian
2016-10-04 20:12 ` Al Viro
2016-10-05 14:30 ` CAI Qian
2016-10-05 16:07 ` Al Viro
2016-09-09 2:31 ` xfs_file_splice_read: possible circular locking dependency detected Al Viro
2016-09-09 2:39 ` Linus Torvalds
2016-09-09 2:26 ` Al Viro
2016-09-09 2:19 ` Al Viro
2016-09-08 18:01 ` Linus Torvalds
2016-09-08 20:39 ` CAI Qian
2016-09-08 21:19 ` Dave Chinner [this message]
2016-09-08 21:30 ` Al Viro
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