[RFC][PATCH] fs: configfs: programmatically create config groups

[Andrzej Pietrasiewicz]

In some parts of the kernel (e.g. planned configfs integration into usb
gadget) there is a need to programmatically create config groups
(directories) but it would be preferable to disallow creating them by
the user. This is more or less what default_groups used to be for.
But e.g. in the mass storage gadget, after storing the number of
luns (logical units) into some configfs attribute, the corresponding lun#
directories should be created, their number is not known up front so
default_groups are no good for this.

Example:

$ echo 3 > /cfg/..../mass_storage/luns

causes

/cfg/....../mass_storage/lun0
/cfg/....../mass_storage/lun1
/cfg/....../mass_storage/lun2

to be created. Yet

$ mkdir /cfg/..../mass_storage/<any name>

should not be allowed.

With create_group exported it is very easily achieved: make_group and make_item
are set to NULL in mass_storage's config_group, yet the kernel can
create_groups at will.

I kindly ask for comments. In particular, I would like to discuss
if this is the right approach. A counterpart to remove config groups
is also required. It is not implemented in this patch, though. What are
your opinions?

Andrzej Pietrasiewicz (1):
  fs: configfs: allow other kernel parts to programmatically create
    config groups

 fs/configfs/dir.c        |    5 +++--
 include/linux/configfs.h |    2 ++
 2 files changed, 5 insertions(+), 2 deletions(-)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/