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Date:   Wed, 15 Jan 2020 12:49:30 +0800
From:   Murphy Zhou <jencce.kernel@gmail.com>
To:     linux-nfs@vger.kernel.org
Subject: Re: [PATCH] fs/nfs, swapon: check holes in swapfile
Message-ID: <20200115044930.mx4477ogjsbrn6hg@xzhoux.usersys.redhat.com>
References: <20200102080426.byzq4rrdilr2qxx6@xzhoux.usersys.redhat.com>
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On Thu, Jan 02, 2020 at 04:04:26PM +0800, Murphy Zhou wrote:
> swapon over NFS does not go through generic_swapfile_activate
> code path when setting up extents. This makes holes in NFS
> swapfiles possible which is not expected for swapon.

Any review?

> 
> Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
> ---
>  fs/nfs/file.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index 8eb731d..ccd9bc0 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -489,7 +489,19 @@ static int nfs_launder_page(struct page *page)
>  static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
>  						sector_t *span)
>  {
> +	unsigned long blocks;
> +	long long isize;
>  	struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
> +	struct inode *inode = file->f_mapping->host;
> +
> +	spin_lock(&inode->i_lock);
> +	blocks = inode->i_blocks;
> +	isize = inode->i_size;
> +	spin_unlock(&inode->i_lock);
> +	if (blocks*512 < isize) {
> +		pr_warn("swap activate: swapfile has holes\n");
> +		return -EINVAL;
> +	}
>  
>  	*span = sis->pages;
>  
> -- 
> 1.8.3.1
>