[ENBD] Re: problems using enbd with kernel 2.6

[P.T. Breuer]

In article <20040318130939.GA8983 at fleece> you wrote:
> I hope someone can help with the following, as I can't think of what
> else to try.
> 
> I've been using enbd successfully with server and client machines
> running 2.4 kernels.  What I want to do now is use kernel 2.6.4 on a
> client machine.
> 
> I'm using the latest (18 Mar) nbd-development.tgz.  (I've also tried
> nbd-2.4.31.tgz with similar results.)  I patch the kernel with
> enbd-2.6.3.pat, and configure:
> 
> CONFIG_ENBD=y
> CONFIG_BLK_DEV_ENBD=m
> CONFIG_BLK_DEV_ENBD_IOCTL=m
> 
> Initial I tried compiling the kernel with gcc-3.3.3.  This produces a

This is one mistake. I'd "go back to start, do not collect $200".


> number of warnings:

> Not sure whether I should be worried about these.  I've also used
> gcc-2.95.3.  This only produces the one innocuous looking warning:

That's fine. I use 2.95.4.

>   CC [M]  drivers/block/enbd/enbd_base.o
> drivers/block/enbd/enbd_base.c: In function `enbd_set_remote_invalid':
> drivers/block/enbd/enbd_base.c:2941: warning: unused variable `bdev'
> 
> I can't get things to work though, whichever compiler I use.  I boot the
> new kernel, compile the user-space tools (using kernel 2.4.21 headers),
> and on the server:

That's OK.

> # enbd-server 5000 -i foo -b 4096 -r /dev/hda
> 
> and on the client:
> 
> # modprobe enbd
> # enbd-client server:5000 -n 2 -i foo -b 4096 /dev/nd/a
> 
> (the client is using devfs) which results in the following:


> enbd-client  6939: client (-1) manager launched daemon 0 (6940) for fleece:7002
> enbd-client  6941: client (1) opens device /dev/nd/a/2
> enbd-client  6939: client (-1) manager launched daemon 1 (6941) for fleece:7002
> enbd-client  6940: <#1962> start_client client (-1) childminder failed to open subdevice 1 for daemon (0)
> enbd-client  6941: <#1962> start_client client (-1) childminder failed to open subdevice 2 for daemon (1)

You don't have the subdevices, apparently (/dev/nd/a/1 etc).  Make
and retry. But the kernel log would tell us.  You should have them,
since devfs is operative. OTOH I  haven't used devfs for years now, and
it is possible that something is now wrong in the code wrt devfs.

> Any suggestions as to what I'm doing wrong here would be greatly
> appreciated.

Show kernel log and /proc/nbdinfo. Also running "make test" would be
useful!

Peter