aufs: bugfix, instantiate-revalidate race

Caching d_inode should be after write_locking the aufs dentry.
Otherwise a race condition happen between instantiate and revalidate on
the same dentry and aufs_d_revalidate() makes the dentry invalid
incorrectly. But there is nothing wrong happens except a small overhead.
This problem was discoverd during a test on linux-3.17-rc1 which
prohibits aliased dentries on a single directory inode explicitly.

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: possible bugfix, temporary d_inode

d_inode is protected by d_lock, so lock/unlock it in au_cpup_or_link().
Actually there is nothing wrong happened without d_lock since the aufs
dentry is already write-locked. But lock/unlock should be here
theoretically.

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: tiny, cosmetic cleanup

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: debug, au_dbg_mtx to serialize the messages

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
Merge remote-tracking branch 'aufs3-standalone/aufs3.9/00base' into aufs3.9/10static
Merge branch 'aufs3.9/10static' into aufs3.9/11proc_map
aufs: fhsm and br_del, allow the root dir only 1/2

By the commit,
d306ff4 2014-07-25 aufs: allow deleting a branch who has an opened dir
br_del() began supporting the opened dirs on the deleting branch.
But it may invite some unnecessary confusion. The necessary thing is to
allow the opened root dir in deleting a branch.

This commit limits ioctl(AUFS_CTL_FHSM_FD) for the roor dir only. And
next commit limits the opened root dir only on the deleting branch.

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: fhsm and br_del, allow the root dir only 2/2

See the previous commit.

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
Merge remote-tracking branch 'aufs3-standalone/aufs3.9/00base' into aufs3.9/10static
Merge branch 'aufs3.9/10static' into aufs3.9/11proc_map
aufs: MAINTAINERS

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: tiny, cosmetic level optimization

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
Merge remote-tracking branch 'aufs3-standalone/aufs3.9/00base' into aufs3.9/10static
Merge branch 'aufs3.9/10static' into aufs3.9/11proc_map
Merge branch 'aufs3.9/00base' into aufs3.10/00base
Merge branch 'aufs3.9/10static' into aufs3.10/10static
Merge remote-tracking branch 'aufs3-standalone/aufs3.10/00base' into aufs3.10/10static
Merge branch 'aufs3.9/11proc_map' into aufs3.10/11proc_map
Merge branch 'aufs3.10/10static' into aufs3.10/11proc_map
Merge branch 'aufs3.10/00base' into aufs3.11/00base