* SHOST_RECOVERY hang with host_busy < host_failed
@ 2016-05-16 22:37 Tyrel Datwyler
0 siblings, 0 replies; only message in thread
From: Tyrel Datwyler @ 2016-05-16 22:37 UTC (permalink / raw)
To: linux-scsi@vger.kernel.org; +Cc: Brian King
I'm seeing a non-deterministic I/O hang with the ibmvfc driver when we
migrate a guest/partition to a different machine. So, on the occasions
when this hits the systems becomes unresponsive blocked on I/O. I
started by inspecting Scsi_Host of the driver which shows shost->state =
SHOST_RECOVERY explaining the blocked I/O. What I found a little weird
however was shost->host_failed > shost->host_busy.
>From the EH documentation SHOST_RECOVERY is set by scsi_eh_scmd_add thus
blocking any new scmd's from the block queue to the host. So, every
scmnd in flight either completes or fails with failed commands being
inclusive of busy commands count, and the EH thread started once all
busy commands are failed commands (ie. host_busy == host_failed). So,
this should mean host_failed should never by greater than host_busy,
correct?
-Tyrel
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2016-05-16 22:37 SHOST_RECOVERY hang with host_busy < host_failed Tyrel Datwyler
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