cleanup block device inode syncing

[Christoph Hellwig <hch@xxxxxx>]

Hi Jens,

this series refactors parts of the sync code so that we have and always
use proper helpers for syncing data cached in the block device inode.

Diffstat:
 block/bdev.c                       |   28 +++++++++++-----
 drivers/block/xen-blkback/xenbus.c |    2 -
 fs/btrfs/volumes.c                 |    2 -
 fs/fat/inode.c                     |    6 +--
 fs/internal.h                      |   11 ------
 fs/ntfs3/inode.c                   |    2 -
 fs/sync.c                          |   62 +++++++++++++------------------------
 include/linux/blkdev.h             |    9 +++++
 8 files changed, 56 insertions(+), 66 deletions(-)