From: Dave Chinner <david@fromorbit.com>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Jiaying Zhang <jiayingz@google.com>, linux-ext4@vger.kernel.org
Subject: Re: [URGENT PATCH] ext4: fix potential deadlock in ext4_evict_inode()
Date: Fri, 26 Aug 2011 18:44:03 +1000 [thread overview]
Message-ID: <20110826084403.GA3162@dastard> (raw)
In-Reply-To: <20110826073507.GZ3162@dastard>
On Fri, Aug 26, 2011 at 05:35:07PM +1000, Dave Chinner wrote:
> On Thu, Aug 25, 2011 at 11:33:44PM -0400, Theodore Ts'o wrote:
> >
> > Note: this will probably need to be sent to Linus as an emergency
> > bugfix ASAP, since it was introduced in 3.1-rc1, so it represents a
> > regression.
>
> It doesn't appear to be a bug. All of the new ext4 lockdep reports
> in 3.1 I've seen (except for the mmap_sem/i_mutex one) are false
> positives....
While the lockdep report is false positive, I agree that your
change is the right fix to make - the IO completions are already
queued on the workqueue, so they don't need to be flushed to get
them to complete. All that needs to be done is call
ext4_ioend_wait() for them to complete, and that gets rid of the
i_mutex altogether. (*)
Sorry for the noise, Ted.
Cheers,
Dave.
(*) Even better would be to get rid of that flush list altogether
and just use ext4_ioend_wait() everywhere....
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2011-08-26 8:44 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-26 3:33 [URGENT PATCH] ext4: fix potential deadlock in ext4_evict_inode() Theodore Ts'o
2011-08-26 3:56 ` Tao Ma
2011-08-26 9:28 ` Tao Ma
2011-08-26 7:35 ` Dave Chinner
2011-08-26 7:42 ` Tao Ma
2011-08-26 8:44 ` Dave Chinner [this message]
2011-08-26 8:50 ` Christoph Hellwig
2011-08-26 9:10 ` Tao Ma
2011-08-26 9:17 ` Christoph Hellwig
2011-08-26 11:35 ` Theodore Tso
2011-08-26 14:53 ` Tao Ma
2011-08-26 9:03 ` Tao Ma
2011-08-26 9:24 ` Dave Chinner
2011-08-26 9:27 ` Tao Ma
2011-08-26 15:52 ` Ted Ts'o
2011-08-26 16:58 ` Jiaying Zhang
2011-08-26 20:22 ` Ted Ts'o
2011-08-27 5:17 ` Jiaying Zhang
2011-08-31 1:15 ` Jiaying Zhang
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