[Ocfs2-devel] [PATCH 1/2] ocfs2: fix zero out valid data

Joseph Qi joseph.qi at linux.alibaba.com
Tue Jul 20 18:54:25 PDT 2021



On 7/14/21 5:13 AM, Junxiao Bi wrote:
> If append-dio feature is enabled, direct-io write and fallocate could run
> in parallel to extend file size, fallocate used "orig_isize" to record
> i_size before taking "ip_alloc_sem", when ocfs2_zeroout_partial_cluster()
> zeroout EOF blocks, i_size maybe already extended by ocfs2_dio_end_io_write(),
> that will cause valid data zeroed out.
> 
> Fixes: 1733438b1d06 ("ocfs2: fix data corruption by fallocate")

Fixes: 6bba4471f0cc ("ocfs2: fix data corruption by fallocate")

With the above fixed,
Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com> 

> Signed-off-by: Junxiao Bi <junxiao.bi at oracle.com>> Cc: <stable at vger.kernel.org>
> ---
>  fs/ocfs2/file.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index 775657943057..53bb46ce3cbb 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -1935,7 +1935,6 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode,
>  		goto out_inode_unlock;
>  	}
>  
> -	orig_isize = i_size_read(inode);
>  	switch (sr->l_whence) {
>  	case 0: /*SEEK_SET*/
>  		break;
> @@ -1943,7 +1942,7 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode,
>  		sr->l_start += f_pos;
>  		break;
>  	case 2: /*SEEK_END*/
> -		sr->l_start += orig_isize;
> +		sr->l_start += i_size_read(inode);
>  		break;
>  	default:
>  		ret = -EINVAL;
> @@ -1998,6 +1997,7 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode,
>  		ret = -EINVAL;
>  	}
>  
> +	orig_isize = i_size_read(inode);
>  	/* zeroout eof blocks in the cluster. */
>  	if (!ret && change_size && orig_isize < size) {
>  		ret = ocfs2_zeroout_partial_cluster(inode, orig_isize,
> 



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