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Date: Thu, 17 Dec 2009 09:32:16 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Christoph Hellwig <hch@lst.de>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Andrew Morton <akpm@linux-foundation.org>,
       Dave Chinner <david@fromorbit.com>,
       Badari Pulavarty <pbadari@us.ibm.com>, Jeff Moyer <jmoyer@redhat.com>,
       Jens Axboe <jens.axboe@oracle.com>, Zach Brown <zach.brown@oracle.com>,
       Alex Elder <aelder@sgi.com>, Mark Fasheh <mfasheh@suse.com>,
       Joel Becker <joel.becker@oracle.com>
Subject: Re: -tip: origin tree boot crash
Message-ID: <20091217093216.GZ14381@ZenIV.linux.org.uk>
References: <20091217090250.GA4844@elte.hu>
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On Thu, Dec 17, 2009 at 10:02:50AM +0100, Ingo Molnar wrote:
> 
> Today's -tip crashes during bootup on one of my testsystems, and i've bisected 
> it back to this commit:
> 
> | 5fe878ae7f82fbf0830dbfaee4c5ca18f3aee442 is the first bad commit
> | commit 5fe878ae7f82fbf0830dbfaee4c5ca18f3aee442
> | Author: Christoph Hellwig <hch@lst.de>
> | Date:   Tue Dec 15 16:47:50 2009 -0800
> |
> |    direct-io: cleanup blockdev_direct_IO locking
> |
> |    Currently the locking in blockdev_direct_IO is a mess, we have three
> |    different locking types and very confusing checks for some of them.  The
> |    most complicated one is DIO_OWN_LOCKING for reads, which happens to not
> |    actually be used.
> 
> I have no bootlog available currently. The kernel config is attached.
> 
> I've reverted the patch from -tip for now.

How about this:

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 4012885..e82adc2 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1206,7 +1206,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	 * NOTE: filesystems with their own locking have to handle this
 	 * on their own.
 	 */
-	if (dio->flags & DIO_LOCKING) {
+	if (flags & DIO_LOCKING) {
 		if (unlikely((rw & WRITE) && retval < 0)) {
 			loff_t isize = i_size_read(inode);
 			if (end > isize)