[Drbd-dev] [request][patch] adding sysfs entry for backing_dev info

[Philipp Reisner]

Am Dienstag, 12. März 2013, 16:36:46 schrieb MITSUNARI Shigeo:
> Hi, all.
> 
> We are using drbdsetup directly without drbdadm and configuration files
> in order to configure DRBD resources dynamically.  Most operations can
> be done without configuration files except one.
> 

Right, this is a valid use case.

> Currently, the kernel does not provide information about the attached
> backing devices.

This statement is wrong. The output of "drbdsetup show" contains the
backing device.

> Without the information, we cannot implement such dynamic configurations
> in a state-less manner.
> 
> The attached patch exposes the backing device information via sysfs entry.
> 

You need to know that we have implemented some sysfs support with 8.3.14
(exposing some UUIDs). But it was rejected when we tried to forward this
sysfs support to our in-linux-tree DRBD.

It was rejected to put a new directory under /sys/block/drbd0. See
https://lkml.org/lkml/2012/10/3/254

We might consider to retry it with DRBD as a seperate bus. I.e. /sys/bus/drbd
at a later point in time.

I.e. so far, you patch will _not_ be accepted by us into the out-of-tree DRBD.

Best regards,
 Philipp