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Subject: Re: [PATCH] fix page_count in ->iomap_migrate_page()
To: zhangjun <openzhangj@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Richard Weinberger <richard@nod.at>,
        "Darrick J . Wong" <darrick.wong@oracle.com>,
        Andrew Morton <akpm@linux-foundation.org>
References: <1544766961-3492-1-git-send-email-openzhangj@gmail.com>
From: Gao Xiang <hsiangkao@mail.ru>
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Date: Sat, 15 Dec 2018 12:26:25 +0800
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On 2018/12/14 13:56, zhangjun wrote:
> IOMAP uses PG_private a little different with buffer_head based
> filesystem.
> It uses it as marker and when set, the page counter is not incremented,
> migrate_page_move_mapping() assumes that PG_private indicates a counter
> of +1.
> so, we have to pass a extra count of -1 to migrate_page_move_mapping()
> if the flag is set.
> 
> Signed-off-by: zhangjun <openzhangj@gmail.com>
> ---

I found that it fixed in
https://patchwork.kernel.org/patch/10684835/
and has been merged in
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=61c6de667263184125d5ca75e894fcad632b0dd3

It seems it has been corrected by Piotr.

Thanks,
Gao Xiang