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Date: Tue, 14 Jul 2015 15:38:25 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Paul McKenney <paulmck@linux.vnet.ibm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Daniel Wagner <daniel.wagner@bmw-carit.de>,
        Davidlohr Bueso <dave@stgolabs.net>, Ingo Molnar <mingo@redhat.com>,
        Tejun Heo <tj@kernel.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] change get_super_thawed() to use
	sb_start/end_write()
Message-ID: <20150714133825.GB24837@redhat.com>
References: <20150713212536.GA13855@redhat.com> <20150713212548.GA13873@redhat.com> <20150714104922.GC24369@quack.suse.cz>
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On 07/14, Jan Kara wrote:
>
> > @@ -621,8 +621,8 @@ struct super_block *get_super_thawed(struct block_device *bdev)
> >  		if (!s || s->s_writers.frozen == SB_UNFROZEN)
> >  			return s;
> >  		up_read(&s->s_umount);
> > -		wait_event(s->s_writers.wait_unfrozen,
> > -			   s->s_writers.frozen == SB_UNFROZEN);
> > +		sb_start_write(s);
> > +		sb_end_intwrite(s);
>
> This is definitely buggy - you need to start and end freeze protection at
> the same level...

Of course ;) copy-and-paste bug. Thanks!

Oleg.