From: Christoph Hellwig <hch@lst.de>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: getting rid of filp search in fs_may_remount_ro()
Date: Wed, 2 Jan 2008 21:33:57 +0100 [thread overview]
Message-ID: <20080102203357.GB884@lst.de> (raw)
In-Reply-To: <1199141688.13731.35.camel@localhost>
On Mon, Dec 31, 2007 at 02:54:48PM -0800, Dave Hansen wrote:
> Here's one blatantly untested idea I have. The idea is to keep track if
> anyone might be writing to a mnt. We keep track on a flag in the mnt.
> When we set the flag, we increment a counter in the sb and decrement
> when the flag is cleared.
>
> We can't simply look at mnt->__mnt_writers because there might be
> "checked-out" writers in the mnt_writers[] array. We also have to keep
> new writers from coming in while we do this, so we use the spinlocks in
> the mnt_writers[] array for exclusion. This is a pretty heavyweight
> lock, but it only gets used at rw->ro transitions.
This idea looks good to me, but if you're going to a final version
please just inline fs_may_remount_ro into its only caller.
next prev parent reply other threads:[~2008-01-02 20:34 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20071126135220.GA17244@lst.de>
[not found] ` <20071226141214.GA31455@lst.de>
2007-12-31 19:54 ` getting rid of filp search in fs_may_remount_ro() Dave Hansen
2007-12-31 22:54 ` Dave Hansen
2008-01-02 20:33 ` Christoph Hellwig [this message]
2008-01-02 20:31 ` Christoph Hellwig
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=20080102203357.GB884@lst.de \
--to=hch@lst.de \
--cc=haveblue@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
/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