[dm-devel] SUSE multipath-tools patch resync

[Hannes Reinecke]

On 05/25/2011 02:22 PM, Christophe Varoqui wrote:
>> Well, forget it ... it was just a matter of 'make clean&&  make' as some
>> structures changed length.
>>
>> The merge is over and pushed to korg.
>> I catched only to problems.
>> You might want to review the fixes.
>>
> Hmm, there might be other problems.
>
> on a 'multipathd reconfigure' command, the uxclient gets stuck and the
> multipathd daemon strace shows:
>
> $ sudo strace -f -p 17721
> Process 17721 attached with 7 threads - interrupt to quit
> [pid 17757] futex(0x7fdc6a1540a4, FUTEX_WAIT_PRIVATE, 3, NULL
> <unfinished ...>
> [pid 17756] futex(0x11167f0, FUTEX_WAIT_PRIVATE, 2, NULL
> <unfinished ...>
> [pid 17755] ioctl(3, DM_DEV_WAIT<unfinished ...>
> [pid 17724] futex(0x11167f0, FUTEX_WAIT_PRIVATE, 2, NULL
> <unfinished ...>
> [pid 17723] recvmsg(6,<unfinished ...>
> [pid 17722] futex(0x110a1b4, FUTEX_WAIT_PRIVATE, 15, NULL
> <unfinished ...>
> [pid 17721] futex(0x612624, FUTEX_WAIT_PRIVATE, 1, NULL
>
I've just send some more fixes which have been uncovered during
recent tests.

- Use refcounting for sysfs devices: We do use sysdev_get() and
   sysdev_put(), but forgot to refcount them. So occasionally
   uevents would try to call sysdev_put() on already freed devices.
- Race condition during shutdown with stop_waiter_thread():
   Trying to access anything inside the waiter structure is
   suicidal, as the waiter thread might be gone at any time.
- Do not handle external renames from multipathd thread:
   Fallout from the above patch; and what's more, the external
   rename should be handled by the waiter thread already.
   So no point in doing so from the daemon itself.

Patches should appear on the mailing list pretty soon.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare at suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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