From: Li Zefan <lizf@cn.fujitsu.com>
To: "Yan, Zheng" <zheng.z.yan@intel.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] btrfs: check file extent backref offset underflow
Date: Mon, 29 Aug 2011 09:59:13 +0800 [thread overview]
Message-ID: <4E5AF271.9040606@cn.fujitsu.com> (raw)
In-Reply-To: <4E5AEAA1.1070200@intel.com>
Yan, Zheng wrote:
> Offset field in data extent backref can underflow if clone range ioctl
> is used. We can reliably detect the underflow because max file size is
> limited to 2^63 and max data extent size is limited by block group size.
>
> Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
...
> @@ -3323,8 +3323,11 @@ static int find_data_references(struct reloc_control *rc,
> }
>
> key.objectid = ref_objectid;
> - key.offset = ref_offset;
> key.type = BTRFS_EXTENT_DATA_KEY;
> + if (ref_offset > ((u64)-1 << 32))
> + key.offset = 0;
> + else
> + key.offset = ref_offset;
This needs comment, as we're working around a corner case and a magic number is
used.
>
> path->search_commit_root = 1;
> path->skip_locking = 1;
> --
prev parent reply other threads:[~2011-08-29 1:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-29 1:25 [PATCH] btrfs: check file extent backref offset underflow Yan, Zheng
2011-08-29 1:59 ` Li Zefan [this message]
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