[PATCHES] finish_no_open() calling conventions change

[Al Viro <viro@zeniv.linux.org.uk>]

	finish_no_open() dentry argument has the same conventions as
->lookup() return value - NULL for "use the dentry we expected to open",
pointer to dentry - "consume a reference to this preexisting alias".
What it does not accept is the third variant of ->lookup() - ERR_PTR(err).
Making finish_no_open() accept that as well (returning err in that case)
simplifies life in ->atomic_open(), especially since the "got a preexisting
alias" is exactly the case when we end up with a positive dentry.

	Branch (-rc5-based) is in
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git work.finish_no_open
Individual patches in followups.

	Please, review - if there's no objections, to -next it goes.

	Shortlog:
allow finish_no_open(file, ERR_PTR(-E...))
9p: simplify v9fs_vfs_atomic_open()
9p: simplify v9fs_vfs_atomic_open_dotl()
simplify cifs_atomic_open()
simplify vboxsf_dir_atomic_open()
simplify nfs_atomic_open_v23()
simplify fuse_atomic_open()
simplify gfs2_atomic_open()
slightly simplify nfs_atomic_open()

	Diffstat:
 fs/9p/vfs_inode.c      | 34 ++++++++++++----------------------
 fs/9p/vfs_inode_dotl.c | 15 +++++----------
 fs/fuse/dir.c          | 21 +++++++--------------
 fs/gfs2/inode.c        | 26 +++++++++-----------------
 fs/nfs/dir.c           | 18 +++++-------------
 fs/open.c              | 10 ++++++----
 fs/smb/client/dir.c    |  8 +-------
 fs/vboxsf/dir.c        | 25 +++++++++----------------
 8 files changed, 54 insertions(+), 103 deletions(-)