[dm-devel] Deadlock on RHEL4 with kpartx/queue_if_no_path - any way out?
Tore Anderson
tore at linpro.no
Mon May 19 09:00:46 UTC 2008
Hi. Due to a PEBCAK and wrong paths being removed I've now ended up
in this situation:
$ multipath -ll multimedia
multimedia (3600a0b80002984ae00001da546c27de1)
[size=200 GB][features="1 queue_if_no_path"][hwhandler="0"]
\_ round-robin 0 [enabled]
\_ #:#:#:# - 65:16 [failed][faulty]
I readded the paths with 'echo - - - > /sys/class/scsi_host/host*/scan',
but the map does not get healthy - all attempts to reload the map with
the multipath tools ends up in blocking I/O, using dmsetup directly I
only get failures due to the map being busy.
This is how the process list looks:
$ ps axf
PID TTY STAT TIME COMMAND
[...]
11598 ? SLl 0:01 /sbin/multipathd
12080 ? S< 0:00 /bin/sh /etc/dev.d/block/multipath.dev block
12087 ? S< 0:00 \_ /sbin/dmsetup ls -j 253 -m 3 --target multipath --exec /sbin/kpartx -a
12088 ? D< 0:00 \_ /sbin/kpartx -a /dev/mapper/multimedia
12714 ? S< 0:00 /bin/sh /etc/dev.d/block/multipath.dev block
12720 ? S< 0:00 \_ /sbin/multipath -v0 /dev/sdb
12794 ? S< 0:00 /bin/sh /etc/dev.d/block/multipath.dev block
12800 ? D< 0:00 \_ /sbin/multipath -v0 /dev/sdc
12831 ? D 0:00 multipath -v 2
14132 ? S< 0:00 /bin/sh /etc/dev.d/block/multipath.dev block
14139 ? S< 0:00 \_ /sbin/dmsetup ls -j 253 -m 3 --target multipath --exec /sbin/kpartx -a
14140 ? D< 0:00 \_ /sbin/kpartx -a /dev/mapper/multimedia
14219 ? S< 0:00 /bin/sh /etc/dev.d/block/multipath.dev block
14225 ? D< 0:00 \_ /sbin/multipath -v0 /dev/sdd
14255 ? D 0:00 multipath -v 2
15312 ? D 0:00 multipath /dev/sdd
17032 ? D 0:00 multipath
1008 ? S< 0:00 /bin/sh /etc/dev.d/block/multipath.dev block
1014 ? D< 0:00 \_ /sbin/multipath -v0 /dev/sde
...I assume the kpartx process is locking the map so no changes can be
done, but since there's no alive paths and queue_if_no_path is active,
it will never return, and I'm stuck in a deadlock.
Is there any way out of this save a reboot?
Regards,
--
Tore Anderson
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