[GIT PULL -mm] 00/12 Unionfs updates/fixes/cleanups

[Erez Zadok <ezk@cs.sunysb.edu>]

The following is a series of patchsets related to Unionfs.  It includes
fixes to a few races discovered since moving to vm_ops->fault, and one small
optimiztion (skip copyup for when a file is opened for writing but no
writing takes place).

These patches were tested (where appropriate) on v2.6.25-4569-gb69d398, MM
(mmotm 2008-04-19-01-17), as well as the backports to
2.6.{25,24,23,22,21,20,19,18,9} on ext2/3/4, xfs (limited testing -- xfs was
oopsing a lot), reiserfs, nfs2/3/4, jffs2, ramfs, tmpfs, cramfs, and
squashfs (where available).  Also tested with LTP-full-20080229 and with a
continuous parallel kernel compile (while forcing cache flushing,
manipulating lower branches, etc.).  See http://unionfs.filesystems.org/ to
download back-ported unionfs code.

Please pull from the 'master' branch of
git://git.kernel.org/pub/scm/linux/kernel/git/ezk/unionfs.git

to receive the following:

Erez Zadok (12):
      Unionfs: minor code cleanups
      Unionfs: prevent races in unionfs_fault
      Unionfs: copy lower times in fsync/fasync only when needed
      Unionfs: lock inode around calls to notify_change()
      Unionfs: stop as soon as first writeable branch is found
      Unionfs: don't dereference dentry without lower branches in d_release
      Unionfs: set append offset correctly for copied-up files
      Unionfs: copyup only if file is being written to
      Unionfs: reorganize file_revalidate for un/locking callers
      Unionfs: maintain one-open-file invariant for non-directories
      Unionfs: set lower file to NULL in file_release
      Unionfs: lock parent dentry branch config in write

 commonfops.c |  248 ++++++++++++++++++++++++++++++++++++++---------------------
 copyup.c     |    2 
 dentry.c     |    4 
 file.c       |   32 +++----
 inode.c      |   43 ++++------
 mmap.c       |   21 +++-
 union.h      |    2 
 7 files changed, 216 insertions(+), 136 deletions(-)

Thanks.
---
Erez Zadok
ezk@cs.sunysb.edu