Commit 0b03cfb2 authored Feb 06, 2008 by Andries E. Brouwer Committed by Linus Torvalds Feb 06, 2008

MNT_UNBINDABLE fix

Some time ago ( http://lkml.org/lkml/2007/6/19/128

 ) I wrote about
MNT_UNBINDABLE that it felt like a bug that it is not reset by "mount
--make-private".

Today I happened to see mount(8) and Documentation/sharedsubtree.txt and
both document the version obtained by applying the little patch given in
the above (and again below).

So, the present kernel code is not according to specs and must be regarded
as buggy.

Specification in Documentation/sharedsubtree.txt:
See state diagram: unbindable should become private upon make-private.

Specification in mount(8):
    ...  It's
    also possible to  set  up  uni-directional  propagation  (with  --make-
    slave),  to  make  a  mount  point unavailable for --bind/--rbind (with
    --make-unbindable), and to undo any  of  these  (with  --make-private).

Repeat of old fix-shared-subtrees-make-private.patch
(due to Dirk Gerrits, René Gabriëls, Peter Kooijmans):

Acked-by: Ram Pai <linuxram@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 870b8f8c

fs/pnode.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -83,6 +83,8 @@ void change_mnt_propagation(struct vfsmount *mnt, int type)
		mnt->mnt_master = NULL;
		if (type == MS_UNBINDABLE)
		mnt->mnt_flags \|= MNT_UNBINDABLE;
		else
		mnt->mnt_flags &= ~MNT_UNBINDABLE;
		}
		}

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