linux-ext4 - Re: ext3: slow symlink corruption on umount...

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Message-ID: <4909F705.8090904@redhat.com>
Date:	Thu, 30 Oct 2008 13:03:49 -0500
From:	Eric Sandeen <sandeen@...hat.com>
To:	Arthur Jones <ajones@...erbed.com>
CC:	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
	"sct@...hat.com" <sct@...hat.com>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: ext3: slow symlink corruption on umount...

Arthur Jones wrote:
> Hi Eric, ...
> 
> On Wed, Oct 29, 2008 at 01:36:33PM -0700, Eric Sandeen wrote:
>> [...]
>> I'll look into it ...
> 
> In the cases that fail, I'm seeing bdi_write_congested()
> return 2 at the top of write_cache_pages().  In the working
> case, bdi_write_congested() returns 0 and the inodes are
> found twice in the s_io list in generic_sync_sb_inodes,
> first as i_state==7, where they are skipped, then a second
> time as i_state==4, where ->writepage() is then called...
> 
> Arthur

Something is definitely racy here; in my simple testcase I get failures
maybe 30-50% of the time...

If I add a mark_buffer_dirty to write_end_fn, it always passes but I
need to think a bit about that.

-Eric

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