On Thu, 20 Nov 2008 19:19:19 +0100 Bernd Schubert <bs@xxxxxxxxx> wrote: > Hello, > > with some FC hardware-raid units we have the problem that the > SYNCHRONIZE_CACHE command reproducibly fails. > > [658715.827428] sd 6:0:2:2: last recovery: 4311805647, now: 4459793681 > [658715.833980] sd 6:0:2:2: [sdk] Result: hostbyte=DID_OK driverbyte=DRIVER_OK,SUGGEST_OK > [658715.842288] sd 6:0:2:2: [sdk] CDB: Synchronize Cache(10): 35 00 00 00 00 00 00 00 00 00 > [658715.850954] sd 6:0:2:2: Activating scsi error recovery (1) > [658715.856793] sd 6:0:2:2: trying to abort command > [658715.861820] qla2xxx 0000:07:02.0: scsi(6:2:2): Abort command issued -- 1 36e2df2 2002. > [658746.004124] sd 6:0:2:2: last recovery: 4459793692, now: 4459801236 > [658746.010686] sd 6:0:2:2: [sdk] Result: hostbyte=DID_OK driverbyte=DRIVER_OK,SUGGEST_OK > [658746.019004] sd 6:0:2:2: [sdk] CDB: Synchronize Cache(10): 35 00 00 00 00 00 00 00 00 00 > [658746.027680] sd 6:0:2:2: Activating scsi error recovery (2) > [658746.033526] sd 6:0:2:2: trying to abort command > [658746.038543] qla2xxx 0000:07:02.0: scsi(6:2:2): Abort command issued -- 1 36e2df4 2002. Does this result in a dead machine, or does the system still struggle along somehow? > My guess is that these units flush their cache when this command is send > even though they have a battery backup unit and flushing 2GB cache may > take some time... Since I can only reproduce it on systems in production > I can't do any experiments, but I guess the default timeout of 30s is not > sufficient. > > Problem is now that this timeout cannot be adjusted by the sysfs scsi device > timeout, since sd_prepare_flush() doesn't have the required device > structure. The reason for that is blk_queue_ordered(). It neither > gets a timeout argument, nor any pointer to the device. > > I already tried to use container_of() in sd_prepare_flush, but somehow > that doesn't seem work if the structure member is a pointer. > > The next solution that comes into my my mind is to add the timeout argument > to blk_queue_ordered() and subsequentely to modifiy all callers. > Would such a patch be accepted? Or is there any better solution? > > Any help is appreciated. Is this problem still open? > > Thanks, > Bernd > > PS: (I'm also discussing the cache flush issue with one of our > hardware vendors, but fixing their firmware might take ages). Making the timeout tunable sounds like a suitable (if minimal) approach. It appears to presently be a qlogic-specific thing? Command_Entry.time_out? -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
