From: Christoph Hellwig <hch@infradead.org>
To: Andrew Morton <akpm@osdl.org>
Cc: Eric Sandeen <sandeen@sandeen.net>, David Chinner <dgc@sgi.com>,
linux-kernel Mailing List <linux-kernel@vger.kernel.org>,
xfs@oss.sgi.com
Subject: Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
Date: Tue, 9 Jan 2007 10:04:20 +0000 [thread overview]
Message-ID: <20070109100420.GB14713@infradead.org> (raw)
In-Reply-To: <20070108195127.67fe86b8.akpm@osdl.org>
On Mon, Jan 08, 2007 at 07:51:27PM -0800, Andrew Morton wrote:
> I don't even know what code we're talking about here...
>
> I'm under the impression that XFS will return to userspace with a
> filesystem lock held, under the expectation (ie: requirement) that
> userspace will later come in and release that lock.
>
> If that's not true, then what _is_ happening in there?
>
> If that _is_ true then, well, that sucks a bit.
It's not a filesystem lock. It's a per-blockdevice lock that prevents
multiple people from freezing the filesystem at the same time, aswell
as providing exclusion between a frozen filesystem an mount-related
activity. It's a traditional text-box example for a semaphore.
next prev parent reply other threads:[~2007-01-09 10:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20070104001420.GA32440@m.safari.iki.fi>
2007-01-07 21:37 ` xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock() David Chinner
2007-01-08 11:03 ` Sami Farin
2007-01-08 16:40 ` Eric Sandeen
2007-01-08 23:47 ` bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock()) David Chinner
2007-01-09 0:19 ` Andrew Morton
2007-01-09 3:12 ` Eric Sandeen
2007-01-09 3:18 ` Andrew Morton
2007-01-09 3:38 ` Eric Sandeen
2007-01-09 3:51 ` Andrew Morton
2007-01-09 4:17 ` Nathan Scott
2007-01-09 4:49 ` David Chinner
2007-01-09 6:02 ` [**BULK SPAM**] " Nathan Scott
2007-01-09 10:04 ` Christoph Hellwig [this message]
2007-01-10 1:34 ` David Chinner
2007-01-09 10:02 ` Christoph Hellwig
2007-01-08 23:56 ` xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock() Andrew Morton
2007-01-09 6:41 ` Ingo Molnar
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