linux-kernel - Re: [PATCH] ocfs2: fix uninitialized variable in ocfs2_dio_wr_get

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Message-ID: <1e9cb07e-aef7-1461-25c4-1e9cfbe41c12@linux.alibaba.com>
Date:   Mon, 6 Dec 2021 14:03:13 +0800
From:   Joseph Qi <joseph.qi@...ux.alibaba.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>,
        Wengang Wang <wen.gang.wang@...cle.com>, ryan.ding@...cle.com,
        Junxiao Bi <junxiao.bi@...cle.com>
Cc:     Joel Becker <jlbec@...lplan.org>,
        Sunil Mushran <sunil.mushran@...cle.com>,
        ocfs2-devel@....oracle.com, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org, Mark Fasheh <mark@...heh.com>
Subject: Re: [PATCH] ocfs2: fix uninitialized variable in
 ocfs2_dio_wr_get_block()



On 12/1/21 10:24 AM, Joseph Qi wrote:
> 
> 
> On 11/30/21 6:40 PM, Dan Carpenter wrote:
>> The callers assume that "*fsdata" is set on the success path, but
>> that's not necessarily true on this path.
>>
> 
> In ocfs2_page_mkwrite(), since in this case no target page locked, it
> will finally return VM_FAULT_NOPAGE (better VM_FAULT_RETRY?) and throw 
> to handle_mm_fault(). So no problem as comments described.
> 
> But things seems changed since append direct io path started to use
> write_[begin/end]. In this path, the target page is expected as NULL.
> This needs more discussion.
> 

ocfs2_grab_pages_for_write() returns EAGAIN only in case of mmap. So
current code won't have any issue.
I'll send a cleanup to make the code more clearly.

Thanks,
Joseph