From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp209.alice.it ([82.57.200.105]:57547 "EHLO smtp209.alice.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750930Ab2IKFNe (ORCPT ); Tue, 11 Sep 2012 01:13:34 -0400 Message-ID: <504EC8BA.7010706@libero.it> Date: Tue, 11 Sep 2012 07:14:34 +0200 From: Goffredo Baroncelli Reply-To: kreijack@inwind.it MIME-Version: 1.0 To: Wang Sheng-Hui CC: chris.mason@fusionio.com, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, cwillu , Josef Bacik Subject: Re: [PATCH] btrfs: fix disk-io.c/btrfs_read_dev_super with BTRFS_SUPER_MIRROR_MAX to control the loops References: <504D8AEB.9090401@gmail.com> In-Reply-To: <504D8AEB.9090401@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi, On 09/10/2012 08:38 AM, Wang Sheng-Hui wrote: > To check the duplicated super blocks, use BTRFS_SUPER_MIRROR_MAX > as the loops limit. > > Signed-off-by: Wang Sheng-Hui > --- > fs/btrfs/disk-io.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 22e98e0..a431144 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -2723,7 +2723,7 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev) > * So, we need to add a special mount option to scan for > * later supers, using BTRFS_SUPER_MIRROR_MAX instead > */ > - for (i = 0; i< 1; i++) { > + for (i = 0; i< BTRFS_SUPER_MIRROR_MAX; i++) { > bytenr = btrfs_sb_offset(i); > if (bytenr + 4096>= i_size_read(bdev->bd_inode)) > break; Pay attention that when a device is removed from a filesystem by the command "btrfs device delete", *only* the 1st superblock btrfs signature is zeroed [1]. This means that the other (backup) superblocks will be considered valid with your change. [1] See the function btrfs_rm_device() in volume.c