linux-kernel - Re: [PATCH] Fix mpage_writepage() for pages with buffers

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Message-ID: <CA+55aFxcMhj1TfBbk3G4XKzu8fjQDYPiFNS0W8pFqMJ6bdA46Q@mail.gmail.com>
Date:   Tue, 10 Oct 2017 13:31:44 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Matthew Wilcox <willy@...radead.org>,
        Johannes Thumshirn <jthumshirn@...e.de>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        "linux-nvdimm@...ts.01.org" <linux-nvdimm@...ts.01.org>,
        OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>,
        Ross Zwisler <ross.zwisler@...ux.intel.com>,
        Toshi Kani <toshi.kani@....com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Fix mpage_writepage() for pages with buffers

On Tue, Oct 10, 2017 at 12:44 PM, Andrew Morton
<akpm@...ux-foundation.org> wrote:
>
> This is all pretty mature code (isn't it?).  Any idea why this bug
> popped up now?

Also, while the patch looks sane, the

        clean_buffers(page, PAGE_SIZE);

line really threw me. That's an insane value to pick, it looks like
"bytes in page", but it isn't. It's just a random value that is bigger
than "PAGE_SIZE >> SECTOR_SHIFT".

I'd prefer to see just ~0u if the intention is just "bigger than
anything possible".

            Linus