RE: [f2fs-dev] f2fs get_dnode_of_data oops

[Chao Yu <chao2.yu@samsung.com>]

Hi Jaegeuk,

Looks good to me!

One nitpick, how about judging this condition before we lock ->i_mutex to
avoid unneeded lock contention and invoking of i_size_read()?

Thanks,
Yu

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, September 09, 2014 12:42 PM
> To: Tommi Rantala
> Cc: Dave Jones; trinity@vger.kernel.org; LKML; linux-f2fs-devel@lists.sourceforge.net
> Subject: Re: [f2fs-dev] f2fs get_dnode_of_data oops
> 
> Hi Tommi,
> 
> This patch should resolve this bug.
> Thanks a lot. :)
> 
> >From ee24677b9917583f50f16b6f59771439f91b890c Mon Sep 17 00:00:00 2001
> From: Jaegeuk Kim <jaegeuk@kernel.org>
> Date: Mon, 8 Sep 2014 10:59:43 -0700
> Subject: [PATCH] f2fs: fix negative value for lseek offset
> 
> If application throws negative value of lseek with SEEK_DATA|SEEK_HOLE,
> previous f2fs went into BUG_ON in get_dnode_of_data, which was reported
> by Tommi Rantala.
> 
> He could make a simple code to detect this having:
> 	lseek(fd, -17595150933902LL, SEEK_DATA);
> 
> This patch should resolve that bug.
> 
> Reported-by: Tommi Rentala <tt.rantala@gmail.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/file.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 9f0ea3d..c9a1295 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -281,7 +281,7 @@ static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence)
>  	mutex_lock(&inode->i_mutex);
> 
>  	isize = i_size_read(inode);
> -	if (offset >= isize)
> +	if (offset >= isize || offset < 0)
>  		goto fail;
> 
>  	/* handle inline data case */
> --
> 1.8.5.2 (Apple Git-48)
> 
> 
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