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Date:   Fri, 6 Sep 2019 16:48:08 -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: fix to avoid accessing uninitialized field of
 inode page in is_alive()
Message-ID: <20190906234808.GC71848@jaegeuk-macbookpro.roam.corp.google.com>
References: <20190906105426.109151-1-yuchao0@huawei.com>
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On 09/06, Chao Yu wrote:
> If inode is newly created, inode page may not synchronize with inode cache,
> so fields like .i_inline or .i_extra_isize could be wrong, in below call
> path, we may access such wrong fields, result in failing to migrate valid
> target block.

If data is valid, how can we get new inode page?

> 
> - gc_data_segment
>  - is_alive
>   - datablock_addr
>    - offset_in_addr
> 
> Fixes: 7a2af766af15 ("f2fs: enhance on-disk inode structure scalability")
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
>  fs/f2fs/dir.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index 765f13354d3f..b1840852967e 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -479,6 +479,9 @@ struct page *f2fs_init_inode_metadata(struct inode *inode, struct inode *dir,
>  		if (IS_ERR(page))
>  			return page;
>  
> +		/* synchronize inode page's data from inode cache */
> +		f2fs_update_inode(inode, page);
> +
>  		if (S_ISDIR(inode->i_mode)) {
>  			/* in order to handle error case */
>  			get_page(page);
> -- 
> 2.18.0.rc1