From: Goffredo Baroncelli <kreijack@libero.it>
To: Wang Sheng-Hui <shhuiw@gmail.com>
Cc: chris.mason@fusionio.com, linux-btrfs@vger.kernel.org,
linux-kernel@vger.kernel.org, cwillu <cwillu@cwillu.com>,
Josef Bacik <jbacik@fusionio.com>
Subject: Re: [PATCH] btrfs: fix disk-io.c/btrfs_read_dev_super with BTRFS_SUPER_MIRROR_MAX to control the loops
Date: Tue, 11 Sep 2012 07:14:34 +0200 [thread overview]
Message-ID: <504EC8BA.7010706@libero.it> (raw)
In-Reply-To: <504D8AEB.9090401@gmail.com>
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<shhuiw@gmail.com>
> ---
> 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
prev parent reply other threads:[~2012-09-11 5:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-10 6:38 [PATCH] btrfs: fix disk-io.c/btrfs_read_dev_super with BTRFS_SUPER_MIRROR_MAX to control the loops Wang Sheng-Hui
2012-09-10 7:24 ` cwillu
2012-09-10 16:14 ` Josef Bacik
2012-09-11 5:14 ` Goffredo Baroncelli [this message]
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