linux-kernel - Re: [PATCH] f2fs: wait writeback before reading data to avoid stale encrypted block

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Date:   Thu, 8 Nov 2018 12:27:13 -0800
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Cc:     stable@...r.kernel.org
Subject: Re: [PATCH] f2fs: wait writeback before reading data to avoid stale
 encrypted block

Let me drop this, since I missed there was a patch to introdcued this. :)

On 11/06, Jaegeuk Kim wrote:
> If background GC is running very frequently by gc_urgent, the next GC
> can see unwritten data generated by the previous GC, which incurs to write
> stale corrupted data in disk.
> 
> Cc: <stable@...r.kernel.org>
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
>  fs/f2fs/gc.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index a07241fb8537..49fea136a3f3 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -658,6 +658,9 @@ static int ra_data_block(struct inode *inode, pgoff_t index)
>  	fio.page = page;
>  	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
>  
> +	/* wait writeback before reading out */
> +	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
> +
>  	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
>  					dn.data_blkaddr,
>  					FGP_LOCK | FGP_CREAT, GFP_NOFS);
> @@ -755,6 +758,9 @@ static int move_data_block(struct inode *inode, block_t bidx,
>  	fio.page = page;
>  	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
>  
> +	/* wait writeback before reading out */
> +	f2fs_wait_on_block_writeback(inode, fio.old_blkaddr);
> +
>  	if (lfs_mode)
>  		down_write(&fio.sbi->io_order_lock);
>  
> -- 
> 2.19.0.605.g01d371f741-goog