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From: Theodore Tso <tytso@MIT.EDU>
To: Mingming Cao <cmm@us.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	linux-ext4@vger.kernel.org
Subject: Re: [RFC PATCH] ext4: Use page_mkwrite vma_operations to get mmap write notification.
Date: Wed, 5 Mar 2008 18:59:41 -0500	[thread overview]
Message-ID: <20080305235941.GD18188@mit.edu> (raw)
In-Reply-To: <1204760238.3713.4.camel@localhost.localdomain>

On Wed, Mar 05, 2008 at 03:37:18PM -0800, Mingming Cao wrote:
> On Wed, 2008-03-05 at 18:29 -0500, Theodore Tso wrote:
> > On Tue, Mar 04, 2008 at 04:45:51PM -0800, Mingming Cao wrote:
> > > > +	/* FIXME!! should we take inode->i_mutex ? Currently we can't because
> > > > +	 * it has a circular locking dependency with DIO. But migrate expect
> > > > +	 * i_mutex to ensure no i_data changes
> > 
> > Should I worry that we have something in the stable part of the patch
> > queue with this FIXME!! comment?  :-)
> > 
> 
> I think this comment could be moved to the migration.c. We can't take
> i_mutex on mapped IO path. The i_data_mutex is the lock that should
> protect the i_data concurrent changes, which is currently mapped IO
> used. The race with migration could be addressed in migration instead of
> here. I propose we drop this comment for now.

OK, but that still means we have a known bug in the migration code,
which is in mainline....

						- Ted

  reply	other threads:[~2008-03-05 23:59 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-04 12:42 [RFC PATCH] ext4: Use page_mkwrite vma_operations to get mmap write notification Aneesh Kumar K.V
2008-03-05  0:45 ` Mingming Cao
2008-03-05 23:29   ` Theodore Tso
2008-03-05 23:37     ` Mingming Cao
2008-03-05 23:59       ` Theodore Tso [this message]
  -- strict thread matches above, loose matches on Subject: below --
2008-02-28 18:05 [RFC][PATCH] " Aneesh Kumar K.V

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