linux-ext4 - Re: [PATCH 03/12] ext4: prevent a fs without journal from being resized

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Date:	Mon, 18 Jul 2011 11:17:04 +0800
From:	Tao Ma <tm@....ma>
To:	Yongqiang Yang <xiaoqiangnk@...il.com>
CC:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 03/12] ext4: prevent a fs without journal from being resized

On 07/18/2011 10:52 AM, Yongqiang Yang wrote:
> This patch prevents a fs without journal from being resized, because
> it is easy to detroy the fs.
Why you want to do this?  You see any corruption?
At least in our product system, no-journal mode is heavily used and we
really don't want to disable this feature.

Thanks
Tao
> 
> Signed-off-by: Yongqiang Yang <xiaoqiangnk@...il.com>
> ---
>  fs/ext4/resize.c |   10 ++++++++++
>  1 files changed, 10 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
> index 53d9795..33ab40d 100644
> --- a/fs/ext4/resize.c
> +++ b/fs/ext4/resize.c
> @@ -33,6 +33,16 @@ int ext4_resize_begin(struct super_block *sb)
>  		return -EPERM;
>  	}
>  
> +	/*
> +	 * We are not allowed to do online-resizing on a filesystem without
> +	 * journal, otherwise, it is easy to destroy the filesystem.
> +	 */
> +	if (!EXT4_SB(sb)->s_journal) {
> +		ext4_warning(sb, "There is no journal for the filesystem, "
> +			     "so online resizing is not allowed\n");
> +		return -EPERM;
> +	}
> +
>  	if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
>  		ret = -EBUSY;
>  

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