From: Eryu Guan <guaneryu@gmail.com>
Subject: Re: xfstests generic/130 hang with non-4k block size ext4 on 4.7-rc1
 kernel
Date: Sun, 12 Jun 2016 11:28:23 +0800
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Cc: Theodore Ts'o <tytso@mit.edu>, Eryu Guan <eguan@redhat.com>,
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To: Jan Kara <jack@suse.cz>
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On Fri, Jun 10, 2016 at 04:37:36PM +0800, Eryu Guan wrote:
> On Wed, Jun 08, 2016 at 02:56:31PM +0200, Jan Kara wrote:
> > On Fri 03-06-16 13:58:44, Jan Kara wrote:
> > > On Fri 03-06-16 18:16:12, Eryu Guan wrote:
> > > > On Thu, Jun 02, 2016 at 02:17:50PM +0200, Jan Kara wrote:
> > > > > 
> > > > > So I was trying but I could not reproduce the hang either. Can you find out
> > > > > which page is jbd2 thread waiting for and dump page->index, page->flags and
> > > > > also bh->b_state, bh->b_blocknr of all 4 buffer heads attached to it via
> > > > > page->private? Maybe that will shed some light...
> > > > 
> > > > I'm using crash on live system when the hang happens, so I got the page
> > > > address from "bt -f"
> > > > 
> > > >  #6 [ffff880212343b40] wait_on_page_bit at ffffffff8119009e
> > > >     ffff880212343b48: ffffea0002c23600 000000000000000d 
> > > >     ffff880212343b58: 0000000000000000 0000000000000000 
> > > >     ffff880212343b68: ffff880213251480 ffffffff810cd000 
> > > >     ffff880212343b78: ffff88021ff27218 ffff88021ff27218 
> > > >     ffff880212343b88: 00000000c1b4a75a ffff880212343c68 
> > > >     ffff880212343b98: ffffffff811901bf
> > > 
> > > Thanks for debugging! In the end I was able to reproduce the issue on my
> > > UML instance as well and I'm debugging what's going on.
> > 
> > Attached patch fixes the issue for me. I'll submit it once a full xfstests
> > run finishes for it (which may take a while as our server room is currently
> > moving to a different place).
> 
> (Sorry for the late reply, I was on holiday yesterday)
> 
> Thanks for the fix! I'll give it a test as well.

I tested this patch with xfstests on x86_64 and ppc64 hosts, all results
look fine, no regression found. Test configurations are: 4k/2k/1k block
size ext4/3/2 and data=journal|writeback ext4.

Thanks,
Eryu