linux-kernel - Re: [PATCH] ocfs2: fix unexpected zeroing of virtual disk

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Message-ID: <ed71901d-bf43-4b81-88ea-0dac7207c5c5@suse.com>
Date: Mon, 19 Aug 2024 10:40:41 +0800
From: Heming Zhao <heming.zhao@...e.com>
To: Joseph Qi <joseph.qi@...ux.alibaba.com>, Chi Zhiling
 <chizhiling@....com>, akpm <akpm@...ux-foundation.org>
Cc: ocfs2-devel@...ts.linux.dev, linux-kernel@...r.kernel.org,
 starzhangzsd@...il.com, Chi Zhiling <chizhiling@...inos.cn>,
 Shida Zhang <zhangshida@...inos.cn>, Mark Fasheh <mark@...heh.com>,
 Joel Becker <jlbec@...lplan.org>
Subject: Re: [PATCH] ocfs2: fix unexpected zeroing of virtual disk

Sorry, I just realized I posted the wrong tag "Signed-off-by: Heming Zhao ...".
The correct should be Reviewed-by: Heming Zhao <heming.zhao@...e.com>.

On 8/19/24 10:32, Joseph Qi wrote:
> Looks good.
> Reviewed-by: Joseph Qi <joseph.qi@...ux.alibaba.com>
> 
> BTW, ocfs2 hasn't been tested thoroughly under 64k page, so I'm afraid
> there are other bugs when running ocfs2 under 64k page.
> 
> On 8/18/24 6:31 PM, Heming Zhao wrote:
>> On 8/15/24 17:21, Chi Zhiling wrote:
>>> From: Chi Zhiling <chizhiling@...inos.cn>
>>>
>>> In a guest virtual machine, we found that there is unexpected data
>>> zeroing problem detected occassionly:
>>>
>>> XFS (vdb): Mounting V5 Filesystem
>>> XFS (vdb): Ending clean mount
>>> XFS (vdb): Metadata CRC error detected at xfs_refcountbt_read_verify+0x2c/0xf0, xfs_refcountbt block 0x200028
>>> XFS (vdb): Unmount and run xfs_repair
>>> XFS (vdb): First 128 bytes of corrupted metadata buffer:
>>> 00000000e0cd2f5e: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>> 00000000cafd57f5: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>> 00000000d0298d7d: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>> 00000000f0698484: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>> 00000000adb789a7: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>> 000000005292b878: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>> 00000000885b4700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>> 00000000fd4b4df7: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>> XFS (vdb): metadata I/O error in "xfs_trans_read_buf_map" at daddr 0x200028 len 8 error 74
>>> XFS (vdb): Error -117 recovering leftover CoW allocations.
>>> XFS (vdb): xfs_do_force_shutdown(0x8) called from line 994 of file fs/xfs/xfs_mount.c.  Return address = 000000003a53523a
>>> XFS (vdb): Corruption of in-memory data detected.  Shutting down filesystem
>>> XFS (vdb): Please umount the filesystem and rectify the problem(s)
>>>
>>> It turns out that the root cause is from the physical host machine.
>>> More specifically, it is caused by the ocfs2.
>>>
>>> when the page_size is 64k, the block should advance by 16 each time
>>> instead of 1.
>>> This will lead to a wrong mapping from the page to the disk, which
>>> will zero some adjacent part of the disk.
>>>
>>> Suggested-by: Shida Zhang <zhangshida@...inos.cn>
>>> Signed-off-by: Chi Zhiling <chizhiling@...inos.cn>
>>> ---
>>>    fs/ocfs2/aops.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
>>> index d6c985cc6353..1fea43c33b6b 100644
>>> --- a/fs/ocfs2/aops.c
>>> +++ b/fs/ocfs2/aops.c
>>> @@ -1187,7 +1187,7 @@ static int ocfs2_write_cluster(struct address_space *mapping,
>>>              /* This is the direct io target page. */
>>>            if (wc->w_pages[i] == NULL) {
>>> -            p_blkno++;
>>> +            p_blkno += (1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits));
>>>                continue;
>>>            }
>>>    
>>
>> Looks good to me.
>> Signed-off-by: Heming Zhao <heming.zhao@...e.com>