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From: Jan Kara <jack@suse.cz>
To: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: Theodore Ts'o <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
	linux-ext4@vger.kernel.org
Subject: Re: REGRESSION: [PATCH 04/12] ext4: Disable merging of uninitialized extents
Date: Thu, 14 Feb 2013 11:47:34 +0100	[thread overview]
Message-ID: <20130214104734.GA605@quack.suse.cz> (raw)
In-Reply-To: <87ehgku11r.fsf@openvz.org>

On Wed 13-02-13 11:26:40, Dmitry Monakhov wrote:
> On Tue, 12 Feb 2013 23:57:59 -0500, Theodore Ts'o <tytso@mit.edu> wrote:
> > On Tue, Feb 12, 2013 at 10:58:32PM +0100, Jan Kara wrote:
> > >   The third patch is a fix which shouldn't cause any issues. So you can
> > > take just that one and leave the other two aside until we are able to
> > > resolve the issue.
> > 
> > I thought the third patch depending on the first two?  Certainly it
> > doesn't apply cleanly without the first two patches...
> My patch fix old issue, but i've prepared it on top of Jan's patches
> only for simplicity. I'll send new version which not depend on his
> patches today.
> Over-all Jan's statment that split should not happen inside end_io
> and it is clear sing of a bug is absolutely right decision.
> This helps us to spot several hidden issues (number is still unknown)
> so may be it is reasonable to split first patch in two parts:
> 1) disable uninitialized extents merging itself.
> 2) Print warning if split is required inside end_io(so only warning will
> be printed, but w/o data corruption)
> 3) Get rid of extent split machinery from end_io (because it is not
> longer valid situation)
> 
> (1) and (2) should be accepted ASAP and will help us to spot and fix
> other hidden issues. And we fix all related issues it will be safe
> to apply (3)'rd one.
> I'll send patches soon.
  I agree with this plan, I just think the warnings are currently too easy
to trigger (just random AIO DIO writing seems to trigger them with
dioread_nolock) so as Ted said we'll probably have to hide them under
EXT4_DEBUG or something like that. I'll try to debug the current problem
while you prepare the patches :).

								Honza

-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

  parent reply	other threads:[~2013-02-14 10:47 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-18 12:00 [PATCH 0/12 v2] ext4: Several simplifications and fixes Jan Kara
2013-01-18 12:00 ` [PATCH 01/12] ext4: Always use ext4_bio_write_page() for writeout Jan Kara
2013-01-28 14:31   ` Theodore Ts'o
2013-01-18 12:00 ` [PATCH 02/12] ext4: Use redirty_page_for_writepage() in ext4_bio_write_page() Jan Kara
2013-01-28 14:34   ` Theodore Ts'o
2013-01-18 12:00 ` [PATCH 03/12] ext4: Remove bogus wait for unwritten extents in ext4_ind_direct_IO Jan Kara
2013-01-22 11:11   ` Dmitry Monakhov
2013-01-22 13:44     ` Jan Kara
2013-01-22 14:12       ` Dmitry Monakhov
2013-01-22 15:21         ` Jan Kara
2013-01-22 14:22       ` Zheng Liu
2013-01-22 15:22         ` Jan Kara
2013-01-22 16:00           ` Zheng Liu
2013-01-22 23:14             ` Jan Kara
2013-01-23  6:11               ` Zheng Liu
2013-01-23  9:42                 ` Jan Kara
2013-01-18 12:00 ` [PATCH 04/12] ext4: Disable merging of uninitialized extents Jan Kara
2013-01-24  9:49   ` Dmitry Monakhov
2013-01-24 15:12     ` Jan Kara
2013-01-24 15:32       ` Dmitry Monakhov
2013-01-28 14:36     ` Theodore Ts'o
2013-01-28 15:02       ` Dmitry Monakhov
2013-01-28 15:38         ` Theodore Ts'o
2013-01-29  7:41           ` Dmitry Monakhov
2013-01-29  8:37             ` Zheng Liu
2013-01-31  7:47     ` Dmitry Monakhov
2013-01-31 12:39       ` Jan Kara
2013-01-31 14:09         ` Dmitry Monakhov
2013-01-31 16:54       ` Theodore Ts'o
2013-02-09 17:10   ` REGRESSION: " Theodore Ts'o
2013-02-12 21:58     ` Jan Kara
2013-02-13  4:57       ` Theodore Ts'o
2013-02-13  7:26         ` Dmitry Monakhov
2013-02-13 15:08           ` Merge window planning for ext4 and Ted's vacation Theodore Ts'o
2013-02-14 10:47           ` Jan Kara [this message]
2013-02-14 16:11     ` REGRESSION: [PATCH 04/12] ext4: Disable merging of uninitialized extents Jan Kara
2013-02-14 19:05       ` Theodore Ts'o
2013-02-14 21:32         ` Jan Kara
2013-01-18 12:00 ` [PATCH 05/12] ext4: Remove unnecessary wait for extent conversion in ext4_fallocate() Jan Kara
2013-01-18 12:00 ` [PATCH 06/12] ext4: Move work from io_end to inode Jan Kara
2013-01-28 14:45   ` Theodore Ts'o
2013-01-18 12:00 ` [PATCH 07/12] ext4: Simplify list handling in ext4_do_flush_completed_IO() Jan Kara
2013-01-28 14:51   ` Theodore Ts'o
2013-01-18 12:00 ` [PATCH 08/12] ext4: Remove __ext4_journalled_writepage() from mpage_da_submit_io() Jan Kara
2013-01-28 14:40   ` Theodore Ts'o
2013-01-18 12:00 ` [PATCH 09/12] ext4: Dirty page has always buffers attached Jan Kara
2013-01-28 17:55   ` Theodore Ts'o
2013-01-18 12:00 ` [PATCH 10/12] ext4: Simplify mpage_add_bh_to_extent() Jan Kara
2013-01-28 18:06   ` Theodore Ts'o
2013-01-18 12:00 ` [PATCH 11/12] ext4: Make ext4_bio_writepage() handle unprepared buffers Jan Kara
2013-01-29  1:59   ` Theodore Ts'o
2013-01-18 12:00 ` [PATCH 12/12] ext4: Fix ext4_writepage() to achieve data=ordered guarantees Jan Kara
2013-01-29  2:08   ` Theodore Ts'o

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