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Date: Thu, 14 Jan 2016 17:13:41 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Tomeu Vizoso <tomeu@tomeuvizoso.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Neil Brown <neilb@suse.com>, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v2 06/11] don't put symlink bodies in pagecache into
 highmem
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On Thu, Jan 14, 2016 at 05:57:42PM +0100, Tomeu Vizoso wrote:
> Here it is:
> 
> [  170.715356] inode: ec8c30b0, pages: 1
> [  170.719014] page_address:   (null)
> 
> https://lava.collabora.co.uk/scheduler/job/127698/log_file

	Lovely...  And that looks like the first time that inode hits
nfs_get_link().  Ho-hum...

	Could you add WARN_ON(inode->i_mapping.nrpages) in inode_nohighmem()
and see if that triggers?  It really shouldn't (we hit it after iget5_locked()
in nfs_fhget() has returned us a new inode, and there shouldn't be a chance
for any pages to get in there between struct inode allocation and that
point), but then neither should highmem pages be added to address_space
without __GFP_HIGHMEM in ->flags...