From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chris Mason <chris.mason@oracle.com>
Subject: Re: Problem found, but why???
Date: Wed, 02 Feb 2011 16:51:01 -0500
Message-ID: <1296683256-sup-5329@think>
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Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nick Piggin <npiggin@suse.de>
To: Boaz Harrosh <bharrosh@panasas.com>
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Excerpts from Boaz Harrosh's message of 2011-02-02 13:46:52 -0500:
> 115e19c53501edc11f730191f7f047736815ae3d is the first bad commit
> commit 115e19c53501edc11f730191f7f047736815ae3d
> Author: Boaz Harrosh <Boaz Harrosh bharrosh@panasas.com>
> 
>     exofs: Set i_mapping->backing_dev_info anyway
> 
> OK It's stupid ME. But why please someone explain this issue?
> For now I'll send a revert, but I would like this explained,
> perhaps a more solid fix is needed.

The bdi_init code doesn't seem to set the ra_pages to a default number.
You got there via kzalloc, so the ra_pages field in your bdi is probably
zero.

This should stop all readahead.

-chris