remove get_super

[Christoph Hellwig <hch@lst.de>]

Hi all,

this series against the VFS vfs.super branch finishes off the work to remove
get_super and move (almost) all upcalls to use the holder ops.

The first part is the missing btrfs bits so that all file systems use the
super_block as holder.

The second part is various block driver cleanups so that we use proper
interfaces instead of raw calls to __invalidate_device and fsync_bdev.

The last part than replaces __invalidate_device and fsync_bdev with upcalls
to the file system through the holder ops, and finally removes get_super.

It leaves user_get_super and get_active_super around.  The former is not
used for upcalls in the traditional sense, but for legacy UAPI that for
some weird reason take a dev_t argument (ustat) or a block device path
(quotactl).  get_active_super is only used for calling into the file system
on freeze and should get a similar treatment, but given that Darrick has
changes to that code queued up already this will be handled in the next
merge window.

A git tree is available here:

    git://git.infradead.org/users/hch/misc.git remove-get_super

Gitweb:

    http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/remove-get_super

Diffstat:
 block/bdev.c              |   61 ++++++++++++++++++++-------------------------
 block/disk-events.c       |   23 ++++-------------
 block/genhd.c             |   45 +++++++++++++++++----------------
 block/ioctl.c             |    9 +++++-
 block/partitions/core.c   |    5 ---
 drivers/block/amiflop.c   |    1 
 drivers/block/floppy.c    |    2 -
 drivers/block/loop.c      |    6 ++--
 drivers/block/nbd.c       |    8 ++---
 drivers/s390/block/dasd.c |    7 +----
 fs/btrfs/disk-io.c        |    4 +-
 fs/btrfs/super.c          |   59 ++++++++++++++++++++++---------------------
 fs/btrfs/volumes.c        |   58 ++++++++++++++++++++++---------------------
 fs/btrfs/volumes.h        |    8 +++--
 fs/inode.c                |   16 +----------
 fs/internal.h             |    2 -
 fs/super.c                |   62 +++++++++++++++-------------------------------
 include/linux/blkdev.h    |   13 +++++----
 include/linux/fs.h        |    1 
 19 files changed, 175 insertions(+), 215 deletions(-)