Pull btrfs fixes from Chris Mason:
"This is an assortment of crash fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: stop all workers before cleaning up roots
Btrfs: fix use-after-free bug during umount
Btrfs: init relocate extent_io_tree with a mapping
btrfs: Drop inode if inode root is NULL
Btrfs: don't delete fs_roots until after we cleanup the transaction