From: Dave Chinner <david@fromorbit.com>
To: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Ted Ts'o <tytso@mit.edu>,
linux-nvdimm@lists.01.org,
Andreas Dilger <adilger.kernel@dilger.ca>,
Jan Kara <jack@suse.com>
Subject: Re: [PATCH] ext4: drop file_update_time from ext4_dax_fault
Date: Tue, 24 Nov 2015 06:55:34 +1100 [thread overview]
Message-ID: <20151123195534.GM19199@dastard> (raw)
In-Reply-To: <20151123141556.GK23418@quack.suse.cz>
On Mon, Nov 23, 2015 at 03:15:56PM +0100, Jan Kara wrote:
> On Fri 20-11-15 14:03:44, Dave Chinner wrote:
> > On Thu, Nov 19, 2015 at 04:18:13PM -0800, Dan Williams wrote:
> > > WARNING: CPU: 0 PID: 2133 at fs/fs-writeback.c:2065 __mark_inode_dirty+0x261/0x350()
> > > bdi-block not registered
> > ^^^^^^^^^^^^^^^^^^^^^^^^
> > > [..]
> > > Call Trace:
> > > [<ffffffff81459f62>] dump_stack+0x44/0x62
> > > [<ffffffff810a2052>] warn_slowpath_common+0x82/0xc0
> > > [<ffffffff810a20ec>] warn_slowpath_fmt+0x5c/0x80
> > > [<ffffffff812831a1>] __mark_inode_dirty+0x261/0x350
> > > [<ffffffff8126d109>] generic_update_time+0x79/0xd0
> > > [<ffffffff8126d28d>] file_update_time+0xbd/0x110
> > > [<ffffffff812e4bc8>] ext4_dax_fault+0x68/0x110
> > > [<ffffffff811f816e>] __do_fault+0x4e/0xf0
> > > [<ffffffff811fc2a7>] handle_mm_fault+0x5e7/0x1b50
> > > [<ffffffff811fbd11>] ? handle_mm_fault+0x51/0x1b50
> > > [<ffffffff810689c1>] __do_page_fault+0x191/0x3f0
> > > [<ffffffff81068cef>] trace_do_page_fault+0x4f/0x120
> > > [<ffffffff8106314a>] do_async_page_fault+0x1a/0xa0
> > > [<ffffffff81902678>] async_page_fault+0x28/0x30
> >
> > Doesn't this indicate some problem at the block/bdi level?
> > __mark_inode_dirty() should not throw warnings like this regardless
> > of where it is called from...
>
> The warning warns that we are dirtying inodes against a backing device that
> advertises it does writeback but is not registered with writeback code (so
> flusher does not run for it). That makes sense but people seem to be
> experimenting a lot with removing devices under filesystems lately and so
> this warning triggers. Probably we have to refine it to not trigger for
> such cases...
Or, alternatively, have the block devices inform the filesystem that
it no longer has a valid bdi backing it. That way the filesystem can
error out at a higher layer and we never get to the point of trying
to mark an inode dirty when the backing device has been unplugged...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
prev parent reply other threads:[~2015-11-23 19:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-20 0:18 [PATCH] ext4: drop file_update_time from ext4_dax_fault Dan Williams
2015-11-20 3:03 ` Dave Chinner
2015-11-20 4:39 ` Dan Williams
2015-11-21 21:32 ` Dave Chinner
2015-11-23 14:15 ` Jan Kara
2015-11-23 19:55 ` Dave Chinner [this message]
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