aufs doc: replace a broken URL

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: tiny, minor optimization for br entries under sysfs

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: describe more about move-down

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: mvdown, return a subset of statfs(2) optionally

Mainly this is for a future feature FHSM (File-based Hierarchy Storage
Management). But aumvdown(8) in aufs-util.git supports this as a hidden
option.

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
aufs: mvdown, tell about the branch is at the bottom

Mainly this is for a future feature FHSM (File-based Hierarchy Storage
Management), and aumvdown(8) in aufs-util.git doesn't care much about
this.

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 'aufs3.10/00base' into aufs3.11/00base
Merge branch 'aufs3.11/00base' into aufs3.12/00base
Merge branch 'aufs3.12/00base' into aufs3.13/00base
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 'aufs3.10/10static' 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 'aufs3.11/10static' into aufs3.12/10static