cleanup filesystem core

[Sascha Hauer]

This series cleans up the filesystem core. The great goal of this series is to
allow unmounting a fileystem by just unregistering the device.
unmount already goes down to unregister a device, but unmount also cleans up
the allocated ressources. We move the filesystem drivers/devices to their own
bus which allows us to clean up the resources in the busses remove function so
that a filesystem can be unmounted *and* cleaned up by unregistering the device.

With this series (and the preceding one) it's possible to call the 'usb' command
on a panda board multiple times without crashing barebox. I tested this with
the onboard USB network adapter and a USB flash drive with a FAT mounted.

Sascha

Sascha Hauer (12):
      add list_is_singular
      dos partitions: Do not register as fixed partitions
      fs: Store mtab entries in list
      fs: make locally used function get_mtab_entry_by_path static
      fs: Store mtab path in allocated string
      fs: remove unused function fsdev_get_mountpoint
      fs: simplify get_mtab_entry_by_path
      fs: remove only once used variable
      fs: remove fs devices list
      fs: put fs devices on its own bus
      fs: allow to mount on subdirectories
      devices: unregister children when unregistering a device

 commands/mount.c      |   17 ++--
 common/partitions.c   |    2 +-
 drivers/base/driver.c |   20 +++-
 fs/fs.c               |  233 ++++++++++++++++++++++--------------------------
 include/fs.h          |   19 ++---
 include/linux/list.h  |    9 ++
 6 files changed, 145 insertions(+), 155 deletions(-)