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From: "Yan Zheng" <yanzheng@21cn.com>
To: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [BUG?] "ext4_ext_put_in_cache" uses __u32 to receive physical block number.
Date: Fri, 27 Jul 2007 13:16:14 +0800	[thread overview]
Message-ID: <3d0408630707262216i3f8e1c35ub49be9c210f963d8@mail.gmail.com> (raw)

Hi, all

I think I found a bug in ext4/extents.c, "ext4_ext_put_in_cache" uses
"__u32" to receive physical block number.  "ext4_ext_put_in_cache" is
used in "ext4_ext_get_blocks", it sets ext4 inode's extent cache
according most recently tree lookup (higher 16 bits of saved physical
block number are always zero). when serving a mapping request,
"ext4_ext_get_blocks" first check whether the logical block is in
inode's extent cache. if the logical block is in the cache and the
cached region isn't a gap, "ext4_ext_get_blocks" gets physical block
number by using cached region's physical block number and offset in
the cached region.  as described above, "ext4_ext_get_blocks" may
return wrong result when there are physical block numbers bigger than
0xffffffff.

Regards

YZ

             reply	other threads:[~2007-07-27  5:16 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-27  5:16 Yan Zheng [this message]
2007-07-27 15:39 ` [BUG?] "ext4_ext_put_in_cache" uses __u32 to receive physical block number Mingming Cao

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