Pull btrfs fixes from David Sterba:
"There's an important revert in this pull request that needs to go to
stable as it causes a corruption on big endian machines.
The other fix is for FIEMAP incorrectly reporting shared extents
before a sync and one fix for a crash in raid56.
So far we got only one report about the BE corruption, the stable
kernels were out for like a week, so hopefully the scope of the damage
is low"
* tag 'for-4.16-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Revert "btrfs: use proper endianness accessors for super_copy"
btrfs: add missing initialization in btrfs_check_shared
btrfs: Fix NULL pointer exception in find_bio_stripe