d5ee37bc Wed Jul 23 22:37:10 CDT 2014 Miao Xie <miaox@cn.fujitsu.com> Btrfs: make the device lock and its protected data in the same cacheline
The lock in btrfs_device structure was far away from its protected data, it would make CPU load the cache line twice when we accessed them, move them together.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>