Btrfs: Fixes for 2.6.18 enterprise kernels

2.6.18 seems to get caught in an infinite loop when
cancel_rearming_delayed_workqueue is called more than once, so this switches
to cancel_delayed_work, which is arguably more correct.

Also, balance_dirty_pages can run into problems with 2.6.18 based kernels
because it doesn't have the per-bdi dirty limits.  This avoids calling
balance_dirty_pages on the btree inode unless there is actually something
to balance, which is a good optimization in general.

Finally there's a compile fix for ordered-data.h

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index b474902c90e2..3814cb0246b4 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -18,6 +18,7 @@
 
 #include <linux/gfp.h>
 #include <linux/slab.h>
+#include <linux/blkdev.h>
 #include "ctree.h"
 #include "transaction.h"
 #include "btrfs_inode.h"