aufs: bugfix, missing mnt_want_write in moo

In move-up-on-open, between copying-up to the upper branch and unlinking
on the lower branch, mnt_want_write is necessary.

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: tiny, move defs to uapi header

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: new ioctl BRINFO

AUFS_CTL_BRINFO returns the information about all branches.
The information is equivalent to the entries under sysfs/fs/aufs, but
this interface is atomic and never confuses the matching of the branch
id.

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
Merge branch 'aufs3.10/10static' into aufs3.11/10static
Merge remote-tracking branch 'aufs3-standalone/aufs3.11/00base' into aufs3.11/10static
Merge branch 'aufs3.10/11proc_map' into aufs3.11/11proc_map
Merge branch 'aufs3.11/10static' into aufs3.11/11proc_map
Merge branch 'aufs3.11/00base' into aufs3.12/00base
Merge branch 'aufs3.11/10static' into aufs3.12/10static
Merge remote-tracking branch 'aufs3-standalone/aufs3.12/00base' into aufs3.12/10static
Merge branch 'aufs3.11/11proc_map' into aufs3.12/11proc_map
Merge branch 'aufs3.12/10static' into aufs3.12/11proc_map