linux-kernel - Re: [PATCH 2/2] f2fs: fix to adjust appropriate length for fiemap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <bf348748-46ba-47dd-a12d-5111be2df95e@kernel.org>
Date: Fri, 1 Nov 2024 10:36:05 +0800
From: Chao Yu <chao@...nel.org>
To: Zhiguo Niu <zhiguo.niu@...soc.com>, jaegeuk@...nel.org
Cc: Chao Yu <chao@...nel.org>, linux-f2fs-devel@...ts.sourceforge.net,
 linux-kernel@...r.kernel.org, niuzhiguo84@...il.com, ke.wang@...soc.com,
 Hao_hao.Wang@...soc.com
Subject: Re: [PATCH 2/2] f2fs: fix to adjust appropriate length for fiemap

On 2024/10/31 13:59, Zhiguo Niu wrote:
> If user give a file size as "length" parameter for fiemap
> operations, but this size is non-block size aligned,
> it will show 2 segments fiemap results even this whole file
> is contiguous on disk, such as the following results, please
> note that this f2fs_io has been modified for testing.
> 
>   ./f2fs_io fiemap 0 19304 ylog/analyzer.py
> Fiemap: offset = 0 len = 19304
>          logical addr.    physical addr.   length           flags
> 0       0000000000000000 0000000020baa000 0000000000004000 00001000
> 1       0000000000004000 0000000020bae000 0000000000001000 00001001
> 
> after this patch:
>   ./f2fs_io fiemap 0 19304 ylog/analyzer.py
> Fiemap: offset = 0 len = 19304
> 	logical addr.    physical addr.   length           flags
> 0	0000000000000000 00000000315f3000 0000000000005000 00001000

Why is FIEMAP_EXTENT_LAST missing in #0 extent? As we can see it
in #1 extent before your change.

1       0000000000004000 0000000020bae000 0000000000001000 00001001

Thanks,

> 
> Signed-off-by: Zhiguo Niu <zhiguo.niu@...soc.com>
> ---
> f2fs_io has been modified for testing, the length for fiemap is
> real file size, not block number
> ---
>   fs/f2fs/data.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 90fa8ab..8c9bb42 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1966,8 +1966,8 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
>   			goto out;
>   	}
>   
> -	if (bytes_to_blks(inode, len) == 0)
> -		len = blks_to_bytes(inode, 1);
> +	if (len & (blks_to_bytes(inode, 1) - 1))
> +		len = round_up(len, blks_to_bytes(inode, 1));
>   
>   	start_blk = bytes_to_blks(inode, start);
>   	last_blk = bytes_to_blks(inode, start + len - 1);