From: Joseph Qi <joseph.qi@linux.alibaba.com>
To: Jan Kara <jack@suse.cz>, Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org, ocfs2-devel@oss.oracle.com
Subject: Re: [Ocfs2-devel] [PATCH 1/2] ocfs2: Fix data corruption on truncate
Date: Thu, 28 Oct 2021 15:44:15 +0800 [thread overview]
Message-ID: <7b6b56f5-e040-1d85-d7a7-e43bf2dcc1fe@linux.alibaba.com> (raw)
In-Reply-To: <f8c309cf-ace7-f8c7-33d2-9a5fa39cb21b@linux.alibaba.com>
On 10/28/21 3:09 PM, Joseph Qi wrote:
> Hi Jan,
>
> On 10/25/21 11:13 PM, Jan Kara wrote:
>> ocfs2_truncate_file() did unmap invalidate page cache pages before
>> zeroing partial tail cluster and setting i_size. Thus some pages could
>> be left (and likely have left if the cluster zeroing happened) in the
>> page cache beyond i_size after truncate finished letting user possibly
>> see stale data once the file was extended again. Also the tail cluster
>
> I don't quite understand the case.
> truncate_inode_pages() will truncate pages from new_i_size to i_size,
> and the following ocfs2_orphan_for_truncate() will zero range and then
> update i_size for inode as well as dinode.
> So once truncate finished, how stale data exposing happens? Or do you
> mean a race case between the above two steps?
>
Or do you mean ocfs2_zero_range_for_truncate() will grab and zero eof
pages? Though it depends on block_write_full_page() to write out, the
pages are zeroed now. Still a little confused...
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next prev parent reply other threads:[~2021-10-28 7:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-25 15:13 [Ocfs2-devel] [PATCH 0/2] ocfs2: Truncate data corruption fix Jan Kara
2021-10-25 15:13 ` [Ocfs2-devel] [PATCH 1/2] ocfs2: Fix data corruption on truncate Jan Kara
2021-10-28 7:09 ` Joseph Qi
2021-10-28 7:44 ` Joseph Qi [this message]
2021-11-01 11:31 ` Jan Kara
2021-11-02 2:36 ` Joseph Qi
2021-11-02 9:55 ` Jan Kara
2021-10-25 15:13 ` [Ocfs2-devel] [PATCH 2/2] ocfs2: Do not zero pages beyond i_size Jan Kara
2021-11-02 2:58 ` Joseph Qi
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