linux-kernel - Re: [PATCH] f2fs: fix out-of-free problem caused by atomic write

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Message-ID: <20171027063854.GA25279@infradead.org>
Date:   Thu, 26 Oct 2017 23:38:54 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     Yunlong Song <yunlong.song@...wei.com>, chao@...nel.org,
        yuchao0@...wei.com, yunlong.song@...oud.com, miaoxie@...wei.com,
        bintian.wang@...wei.com, linux-fsdevel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] f2fs: fix out-of-free problem caused by atomic write

On Thu, Oct 26, 2017 at 04:30:19PM +0200, Jaegeuk Kim wrote:
> On 10/26, Yunlong Song wrote:
> > f2fs_balance_fs only actives once in the commit_inmem_pages, but there
> > are more than one page to commit, so all the other pages will miss the
> > check. This will lead to out-of-free problem when commit a very large
> > file. To fix it, we should do f2fs_balance_fs for each inmem page.
> 
> NAK, this breaks atomicity.

Can someone please explain (and write down in e.g. manpages) these
atomicy rules?