[lxc-devel] [RFC PATCH 1/2] loop: Add loop filesystem

[Seth Forshee]

On Tue, May 27, 2014 at 03:56:53PM -0700, Randy Dunlap wrote:
> On 05/27/2014 02:58 PM, Seth Forshee wrote:
> > Add limited capability for use of loop devices in containers via
> > a loopfs psuedo fs. When mounted this filesystem will contain
> > only a loop-control device node. This can be used to request free
> > loop devices which will be "owned" by that mount. Device nodes
> > appear automatically for these devices, and the same device will
> > not be given to another loopfs mount. Privileged loop ioctls
> > (for encrypted loop) will be allowed within the namespace which
> > mounted the loopfs.
> > 
> > Privileged block ioctls are not permitted, so features such as
> > partitions are not supported for unprivileged users.
> > 
> > Signed-off-by: Seth Forshee <seth.forshee at canonical.com>
> > ---
> >  drivers/block/loop.c       | 110 +++++++++++---
> >  drivers/block/loop.h       |   2 +
> >  fs/Makefile                |   1 +
> >  fs/loopfs/Makefile         |   6 +
> >  fs/loopfs/inode.c          | 349 +++++++++++++++++++++++++++++++++++++++++++++
> >  include/linux/loopfs.h     |  46 ++++++
> >  include/uapi/linux/magic.h |   1 +
> >  7 files changed, 495 insertions(+), 20 deletions(-)
> >  create mode 100644 fs/loopfs/Makefile
> >  create mode 100644 fs/loopfs/inode.c
> >  create mode 100644 include/linux/loopfs.h
> > 
> 
> > diff --git a/fs/loopfs/Makefile b/fs/loopfs/Makefile
> > new file mode 100644
> > index 000000000000..01aedfb2f841
> > --- /dev/null
> > +++ b/fs/loopfs/Makefile
> > @@ -0,0 +1,6 @@
> > +#
> > +# Makefile for the loopfs virtual filesystem
> > +#
> > +
> > +obj-$(CONFIG_BLK_DEV_LOOP)		+= loopfs.o
> > +loopfs-$(CONFIG_BLK_DEV_LOOP)		:= inode.o
> 
> I guess that you need to update the BLK_DEV_LOOP entry in
> drivers/block/Kconfig to mention this?

Sure, I'll do that.