linux-ext4 - Re: [PATCH] ext4: guarantee already started handles to successfully finish while ro remounting

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Message-id: <1656879517.452811462512954933.JavaMail.weblogic@ep2mlwas08c>
Date:	Fri, 06 May 2016 05:35:56 +0000 (GMT)
From:	Daeho Jeong <daeho.jeong@...sung.com>
To:	Jan Kara <jack@...e.cz>
Cc:	"tytso@....edu" <tytso@....edu>,
	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
	정대호 <daeho.jeong@...sung.com>,
	이기태 <kitae87.lee@...sung.com>
Subject: Re: [PATCH] ext4: guarantee already started handles to successfully
 finish while ro remounting

> So can you share a reproducer for this issue? Because my initial thinking
> is that checks during remount should fail the remount with EBUSY if there
> is any modification outstanding... If they don't we have a racy remount and
> fs-freezing code, which is a bug.

Hi Jan,

Sorry to make you confused. My patch description was little wrong.
I meant only the emergency read-only remount case, not the normal read-only
remount case. Android is currently using emergency ro remount for the device
shutdown procedure.

We can easily reproduce this problem, but we didn't make a TC for xfstest yet.
If we did that, I will let you know.