From: Chris Mason <chris.mason@oracle.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: trond.myklebust@fys.uio.no, npiggin@suse.de,
linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: Why doesn't zap_pte_range() call page_mkwrite()
Date: Fri, 24 Apr 2009 08:59:49 -0400 [thread overview]
Message-ID: <1240577989.32585.1.camel@think.oraclecorp.com> (raw)
In-Reply-To: <E1LxFuD-0008M9-1a@pomaz-ex.szeredi.hu>
On Fri, 2009-04-24 at 09:33 +0200, Miklos Szeredi wrote:
> On Fri, 24 Apr 2009, Miklos Szeredi wrote:
> > Hmm, I guess this is a bit nasty: the VM promises filesystems that
> > ->page_mkwrite() will be called when the page is dirtied through a
> > mapping, _almost_ all of the time. Except when munmap happens to race
> > with clear_page_dirty_for_io().
> >
> > I don't have any ideas how this could be fixed, CC-ing linux-mm...
>
> On second thought, we could possibly just ignore the dirty bit in that
> case. Trying to write to a mapping _during_ munmap() will have pretty
> undefined results, I don't think any sane application out there should
> rely on the results of this.
>
> But how knows, the world is a weird place...
It does happen in practice, btrfs has fallback code that triggers the
page_mkwrite when it finds a dirty page that wasn't dirtied with help
from the FS.
I'd love to get rid of the fallback ;)
-chris
next prev parent reply other threads:[~2009-04-24 13:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-23 18:17 Why doesn't zap_pte_range() call page_mkwrite() Trond Myklebust
[not found] ` <1240510668.11148.40.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2009-04-23 19:52 ` Miklos Szeredi
[not found] ` <E1Lx4yU-0007A8-Gl-8f8m9JG5TPIdUIPVzhDTVZP2KDSNp7ea@public.gmane.org>
2009-04-23 20:42 ` Trond Myklebust
2009-04-24 7:15 ` Miklos Szeredi
[not found] ` <E1LxFd4-0008Ih-Rd-8f8m9JG5TPIdUIPVzhDTVZP2KDSNp7ea@public.gmane.org>
2009-04-24 7:33 ` Miklos Szeredi
2009-04-24 12:59 ` Chris Mason [this message]
2009-04-24 13:31 ` Trond Myklebust
2009-04-24 14:06 ` Trond Myklebust
2009-04-24 16:18 ` Jamie Lokier
2009-04-24 10:41 ` Robin Holt
2009-04-24 14:52 ` Miklos Szeredi
[not found] ` <E1LxMlO-0000sU-1J-8f8m9JG5TPIdUIPVzhDTVZP2KDSNp7ea@public.gmane.org>
2009-04-24 17:00 ` Trond Myklebust
[not found] ` <1240592448.4946.35.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2009-04-25 5:10 ` Nick Piggin
2009-09-08 15:30 ` Chris Mason
2009-09-08 15:41 ` Nick Piggin
[not found] ` <20090908154132.GC29902@wotan.suse.de>
2009-09-08 16:31 ` Chris Mason
2009-09-08 17:00 ` Nick Piggin
2009-09-09 2:21 ` Christoph Hellwig
[not found] ` <20090909022102.GA28318@infradead.org>
[not found] ` <20090909022102.GA28318-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2009-09-09 5:39 ` Nick Piggin
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=1240577989.32585.1.camel@think.oraclecorp.com \
--to=chris.mason@oracle.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-nfs@vger.kernel.org \
--cc=miklos@szeredi.hu \
--cc=npiggin@suse.de \
--cc=trond.myklebust@fys.uio.no \
/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).