linux-xfs.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Matthew Wilcox <willy@infradead.org>
To: "yukuai (C)" <yukuai3@huawei.com>
Cc: hch@infradead.org, darrick.wong@oracle.com,
	linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, houtao1@huawei.com,
	zhengbin13@huawei.com, yi.zhang@huawei.com
Subject: Re: [RFC] iomap: fix race between readahead and direct write
Date: Sat, 18 Jan 2020 17:42:13 -0800	[thread overview]
Message-ID: <20200119014213.GA16943@bombadil.infradead.org> (raw)
In-Reply-To: <f5328338-1a2d-38b4-283f-3fb97ad37133@huawei.com>

On Sun, Jan 19, 2020 at 09:34:32AM +0800, yukuai (C) wrote:
> 
> 
> On 2020/1/19 7:08, Matthew Wilcox wrote:
> > It's worth noting that my patch series from earlier this week to
> > redesign the readahead API will fix this problem.  Direct write will block
> > on the locked pages in the page cache.
> 
> Thank you for your response!
> 
> In this case, direct write finish while page do not exist in the page
> cache. This is the fundamental condition of the race, because readahead
> won't allocate page if page exist in page cache.
> 
> By the way, in the current logic, if page exist in page cache, direct
> write need to hold lock for page in invalidate_inode_pages2_range().

Did you read my patch series?  The current code allocates pages,
but does not put them in the page cache until after iomap is called.
My patch series changes that to put the pages in the page cache as soon
as they're allocated, and before iomap is called.

  reply	other threads:[~2020-01-19  1:43 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16  6:36 [RFC] iomap: fix race between readahead and direct write yu kuai
2020-01-16 15:32 ` Jan Kara
2020-01-17  9:39   ` yukuai (C)
2020-01-17 11:05     ` Jan Kara
2020-01-17 16:24       ` Darrick J. Wong
2020-01-19  1:25         ` yukuai (C)
2020-01-19  1:17       ` yukuai (C)
2020-01-20 11:42         ` Jan Kara
2020-01-18 23:08 ` Matthew Wilcox
2020-01-19  1:34   ` yukuai (C)
2020-01-19  1:42     ` Matthew Wilcox [this message]
2020-01-19  1:57       ` yukuai (C)
2020-01-19  2:51       ` yukuai (C)
2020-01-19  3:01         ` Gao Xiang
2020-01-19  3:15           ` yukuai (C)
2020-01-19  6:14         ` Matthew Wilcox
2020-01-19  6:55           ` yukuai (C)
2020-01-19  7:58             ` Matthew Wilcox
2020-01-19 11:21               ` yukuai (C)

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200119014213.GA16943@bombadil.infradead.org \
    --to=willy@infradead.org \
    --cc=darrick.wong@oracle.com \
    --cc=hch@infradead.org \
    --cc=houtao1@huawei.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=yi.zhang@huawei.com \
    --cc=yukuai3@huawei.com \
    --cc=zhengbin13@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).