Btrfs #2 for 3.16

Hi Linus,

Please pull my for-linus branch:

git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs.git for-linus

This has a few fixes since our last pull and a new ioctl for doing btree searches from userland. It's very similar to the existing ioctl, but lets us return larger items back down to the app.

Gerhard Heift (7) commits (+183/-38):
btrfs: tree_search, copy_to_sk: return EOVERFLOW for too small buffer (+26/-2)
btrfs: tree_search, copy_to_sk: return needed size on EOVERFLOW (+15/-9)
btrfs: tree_search, search_ioctl: direct copy to userspace (+33/-15)
btrfs: tree_search, search_ioctl: accept varying buffer (+11/-7)
btrfs: tree_search: eliminate redundant nr_items check (+7/-5)
btrfs: new function read_extent_buffer_to_user (+40/-0)
btrfs: new ioctl TREE_SEARCH_V2 (+51/-0)

Eric Sandeen (3) commits (+11/-7):
btrfs: free ulist in qgroup_shared_accounting() error path (+3/-1)
btrfs: fix use of uninit "ret" in end_extent_writepage() (+1/-1)
btrfs: fix error handling in create_pending_snapshot (+7/-5)

Wang Shilong (1) commits (+7/-2):
Btrfs: fix unfinished readahead thread for raid5/6 degraded mounting

Filipe Manana (1) commits (+2/-0):
Btrfs: fix qgroups sanity test crash or hang

Sasha Levin (1) commits (+1/-1):
btrfs: prevent RCU warning when dereferencing radix tree slot

Total: (13) commits

 fs/btrfs/extent_io.c          |  39 ++++++++++-
 fs/btrfs/extent_io.h          |   3 +
 fs/btrfs/ioctl.c              | 147 ++++++++++++++++++++++++++++++++++--------
 fs/btrfs/qgroup.c             |   4 +-
 fs/btrfs/reada.c              |   9 ++-
 fs/btrfs/tests/btrfs-tests.c  |   2 +-
 fs/btrfs/tests/qgroup-tests.c |   2 +
 fs/btrfs/transaction.c        |  12 ++--
 include/uapi/linux/btrfs.h    |  10 +++
 9 files changed, 192 insertions(+), 36 deletions(-)