From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Kara <jack@suse.cz>
Subject: Re: [PATCH 8/17] fsfreeze: allow bdev level thaws when the sb is
 unfrozen
Date: Wed, 9 Jan 2013 17:26:25 +0100
Message-ID: <20130109162625.GD17353@quack.suse.cz>
References: <1357557492.8183.1.camel@nexus.lab.ntt.co.jp>
 <1357558333.8183.13.camel@nexus.lab.ntt.co.jp>
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Cc: Al Viro <viro@zeniv.linux.org.uk>,
	Josef Bacik <jbacik@fusionio.com>,
	Eric Sandeen <sandeen@redhat.com>,
	Dave Chinner <dchinner@redhat.com>,
	Christoph Hellwig <hch@infradead.org>, Jan Kara <jack@suse.cz>,
	Luiz Capitulino <lcapitulino@redhat.com>,
	linux-fsdevel@vger.kernel.org
To: Fernando Luis =?iso-8859-1?Q?V=E1zquez?= Cao
	<fernando_b1@lab.ntt.co.jp>
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On Mon 07-01-13 20:32:13, Fernando Luis V=E1zquez Cao wrote:
> This behavior is important in a scenario where a filesystem frozen us=
ing
> freeze_bdev() is thawed through the superblock level API; if we
> caused subsequent calls to thaw_bdev() future calls to freeze_bdev()
> would fail to freeze the superblock.
>=20
> We can get rid of this code away once bdev level fsfreeze and sb leve=
l
> fsfreeze are properly integrated.
  OK, makes sence. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>

								Honza
>=20
> Cc: linux-fsdevel@vger.kernel.org
> Cc: Josef Bacik <jbacik@fusionio.com>
> Cc: Eric Sandeen <sandeen@redhat.com>
> Cc: Christoph Hellwig <hch@infradead.org>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Dave Chinner <dchinner@redhat.com>
> Cc: Luiz Capitulino <lcapitulino@redhat.com>
> Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
> ---
>=20
> diff -urNp linux-3.8-rc1-orig/fs/block_dev.c linux-3.8-rc1/fs/block_d=
ev.c
> --- linux-3.8-rc1-orig/fs/block_dev.c	2012-12-25 11:52:04.344018000 +=
0900
> +++ linux-3.8-rc1/fs/block_dev.c	2012-12-25 16:11:12.648018000 +0900
> @@ -272,8 +272,19 @@ int thaw_bdev(struct block_device *bdev,
>  	}
> =20
>  	error =3D thaw_super(sb);
> -	if (error)
> +	/*
> +	 * If the superblock is already unfrozen, i.e. thaw_super() returne=
d
> +	 * -EINVAL, we consider the block device level thaw successful. Thi=
s
> +	 * behavior is important in a scenario where a filesystem frozen us=
ing
> +	 * freeze_bdev() is thawed through the superblock level API; if we
> +	 * caused the subsequent thaw_bdev() to fail bdev->bd_fsfreeze_coun=
t
> +	 * would not go back to 0 which means that future calls to freeze_b=
dev()
> +	 * would not freeze the superblock, just increase the counter.
> +	 */
> +	if (error && error !=3D -EINVAL)
>  		bdev->bd_fsfreeze_count++;
> +	else
> +		error =3D 0;
>  out:
>  	mutex_unlock(&bdev->bd_fsfreeze_mutex);
>  	return error;
>=20
>=20
--=20
Jan Kara <jack@suse.cz>
SUSE Labs, CR
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