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Date:   Thu, 24 Sep 2020 13:03:05 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <yuchao0@huawei.com>
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, chao@kernel.org
Subject: Re: [PATCH] f2fs: compress: fix to disallow enabling compress on
 non-empty file
Message-ID: <20200924200305.GA2568648@google.com>
References: <20200918030349.19667-1-yuchao0@huawei.com>
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In-Reply-To: <20200918030349.19667-1-yuchao0@huawei.com>
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On 09/18, Chao Yu wrote:
> Compressed inode and normal inode has different layout, so we should
> disallow enabling compress on non-empty file to avoid race condition
> during inode .i_addr array parsing and updating.
> 
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
>  fs/f2fs/file.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 58e464cc15f0..139fdfc1dc55 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1821,6 +1821,8 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
>  		if (iflags & F2FS_COMPR_FL) {
>  			if (!f2fs_may_compress(inode))
>  				return -EINVAL;
> +			if (inode->i_size)

Changed like this.

+                       if (S_ISREG(inode->i_mode) && inode->i_size)


> +				return -EINVAL;
>  
>  			set_compress_context(inode);
>  		}
> -- 
> 2.26.2