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Date: Fri, 28 Feb 2014 10:25:24 +0100
From: Richard Weinberger <richard@nod.at>
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To: Christoph Hellwig <hch@infradead.org>,
 Andrew Ruder <andrew.ruder@elecsyscorp.com>
Subject: Re: [HACK] fs/super.c: sync ro remount after blocking writers
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Cc: linux-fsdevel@vger.kernel.org, linux-mtd@lists.infradead.org,
 Alexander Viro <viro@zeniv.linux.org.uk>,
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Andrew,

Am 03.02.2014 11:23, schrieb Christoph Hellwig:
> On Thu, Jan 30, 2014 at 09:26:54AM -0600, Andrew Ruder wrote:
>> Move sync_filesystem() after sb_prepare_remount_readonly().  If writers
>> sneak in anywhere from sync_filesystem() to sb_prepare_remount_readonly()
>> it can cause inodes to be dirtied and writeback to occur well after
>> sys_mount() has completely successfully.
>>
>> This was spotted by corrupted ubifs filesystems on reboot, but appears
>> that it can cause issues with any filesystem using writeback.
> 
> From the link that Richard posted it seems like you have a testcase.
> Can you please integrate it into xfstests so that we can properly
> regression test for this issue from now on?

Is it possible to create such a test case?
I don't know whether it is possible to trigger the issue on
a regular filesystem.
But as hch noted, it would be nice to have. :)

Thanks,
//richard