[Pkg-iscsi-maintainers] Bug#850060: 2.0.874-2~exp1 issues

[Christian Seiler]

Control: reopen -1

Hi,
(reopening the bug report since iscsiuio doesn't actually work
according to what you're telling me)

On 01/04/2017 11:30 PM, Andrew Patterson wrote:
> 1. In debian/extra/initramfs.local-top and
> debian/extra/initramfs.local-bottom /sbin/iscsuio creates a pid file
> in /run/iscsiuio.pid. You cannot override it on the command-line. The
> --pidfile option for start-stop-daemon should point to this location
> instead of /run/initramfs/iscsiuio.pid.

Gah. I thought I had fixed that before the upload. :-(
A good thing there's experimental...

OTOH, initramfs should write to /run/initramfs only, so maybe
we should pass -p /run/initramfs/iscsiuio.pid to iscsiuio
instead as well.

> 2. The /sbin/iscsiuio deamon is trying to create a logfile in
> /var/log/iscsiuio.log. The /var/log directory does not exist in the
> initramfs.

Unfortunately that's hardcoded. OTOH from reading the code
this shouldn't be an issue.

> 3. The iscsiuio daemon is dieing before or during iscsistart -b. I am
> investigating why. It works fine when run after boot.

This is weird, on my test VM (no offloading NIC though) it
does start (and shut down again).

Question: does the network card require firmware for offloading
to work? If that's the case we might need to add the firmware
to the initramfs or this to work properly...

> 4. The commit 02c3051 "Don't ignore offloading NICs in iscsistart"
> will cause the interface to be configured in both iscsistart -N and in
> iscsistart -b for cards with iscsi hardware offload. I suspect we
> instead need a flag in iscsistart to bring up the NIC in iscsistart
> regardless if the NIC uses an offloadable driver. The local-top script
> can use this flag if /sbin/iscsiuio is not present, e.g.,
> 
> ISCSISTART_FLAGS=""
> if [ ! -x /sbin/iscsiuio ] ; then
>    ISCSISTART_FLAGS="-S"
> fi

Hmm, now I see what you mean. I also dug up this commit which
gives a little insight.

https://github.com/open-iscsi/open-iscsi/commit/ee115be828362653478e6fe7cd4c6ee3318223ff

However, I think the solution is different from what you suggest: the
"fix" for #850057 is wrong I believe.

Debian sid package (w/o -DOFFLOAD_BOOT_SUPPORTED):

 - cxgb*i: iscsistart -N ignores interface
           iscsistart -b doesn't configure offloading
       => won't work

 - bnx2i (any mode): iscsistart -N ignores interface
                     iscsistart -b doesn't configure offloading
       => won't work

Current upstream situation (w/ -DOFFLOAD_BOOT_SUPPORTED):

 - cxgb*i: iscsistart -N ignores interface
           iscsistart -b configures offloading 
       => should work
          (but don't have hardware)
          (also: remind me to check whether we copy the
          module into the initramfs)

 - bnx2i non-hba: iscsistart -N ignores it
                  iscsistart -b doesn't configure offloading
       => won't work

 - bnx2i hba: iscsistart -N ignores it
              iscsistart -b configures offloading
       => should work (once iscsiuio is running)

"Fix" for 850057 (in experimental):

 - cxgb*i: iscsistart -N configures interface on host
           iscsistart -b configures offloading
         => no idea what happens thereafter
            (since MAC address is the same on these cards: is
            this a problem if they have the same IP?)

 - bnx2i non-hba: iscsistart -N configures interface
                  iscsistart -b doesn't configure offloading,
                                but enables software iSCSI
          => should work

 - bnx2i hba: iscsistart -N configures interface
              iscsistart -b configures offloading
          => same IP, different MAC addresses
          => will cause trouble

The ideal solution would be to mirror the check that is done
for -b in -N. In that case we'd either configure the host
interface (and use software iSCSI), or configure offloading
(and use hardware iSCSI), but never both, and never neither.
So instead of the current patch for #850057 I would suggest
to do that instead. That should then also be upstream-able. I
can prepare a patch for that tomorrow.

That still leaves us with the question why iscsiuio doesn't
appear to work in the initramfs on your system. You could
just add strace to your initramfs and call iscsiuio in a
detached strace, a la

old:
start-stop-daemon ... /sbin/iscsiuio

new:
start-stop-daemon ... /bin/strace -- -D -f \
   -o /run/initramfs/iscsiuio.trace  -- /sbin/iscsiuio

(The first -- is for start-stop-daemon, the second one for
strace itself.)

Regards,
Christian