From 1135d6df222046a0ec14a1c9335de99907879922 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fusionio.com>
Date: Fri, 14 Dec 2012 13:46:43 -0500
Subject: [PATCH] Btrfs: fix autodefrag and umount lockup

This happens because writeback_inodes_sb_nr_if_idle does down_read.  This
doesn't work for us and it has not been fixed upstream yet, so do it
ourselves and use that instead so we can stop having this stupid long
standing lockup.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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Reading git-format-patch failed