On 07/20/2010 05:19 PM, Robert Love wrote:
From: Vasu Dev<vasu.dev@xxxxxxxxx>
In this case, sync IO fails with EIO(5) errors as:-
"Thread:1 System call error:5 - Input/output error (::pwrite() failed)".
This is due to IO time out while libfc doing link down processing
to block all rports and if timed out IO was at last retry
attempt then it fails to user with EIO error followed by
these log messages.
[77848.612169] host2: rport bf0015: Delete port
[77848.612221] host2: rport e10aef: work delete
[77848.612232] host2: rport e10002: work event 3
[77848.612422] sd 2:0:1:1: [sdi] Unhandled error code
[77848.612426] sd 2:0:1:1: [sdi] Result: hostbyte=DID_ERROR
driverbyte=DRIVER_OK
[77848.612431] sd 2:0:1:1: [sdi] CDB: Write(10): 2a 00 00 00 11 20 00 00 20 00
[77848.612445] end_request: I/O error, dev sdi, sector 4384
[77848.612553] sd 2:0:1:2: [sdj] Unhandled error code
To fix these EIO errors, such timed out incomplete IOs needs
to be re-queued without counting retry attempt and this patch
does that using DID_REQUEUE scsi code.
Signed-off-by: Vasu Dev<vasu.dev@xxxxxxxxx>
Signed-off-by: Robert Love<robert.w.love@xxxxxxxxx>
---
drivers/scsi/libfc/fc_fcp.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c
index a0a3ae7..61a1297 100644
--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -1971,6 +1971,11 @@ static void fc_io_compl(struct fc_fcp_pkt *fsp)
break;
}
+ if (lport->state != LPORT_ST_READY&& fsp->status_code != FC_COMPLETE) {
+ sc_cmd->result = (DID_REQUEUE<< 16);
+ FC_FCP_DBG(fsp, "Returning DID_REQUEUE to scsi-ml\n");
+ }
+
If it is a tape command, you do not want to use DID_REQUEUE do you?
You are using the fc class API to delete the rport in this scenario,
right? If so normally I think you would use DID_TRANSPORT_DISRUPTED.
This is going to give you an error if it is the last retry like
DID_ERROR though.
It seems weird to try and work around the IO erorr in this case because
it is the last retry so it should fail. If the port keeps going down and
up, then with your patch you could keep retrying the IO forever.
This isn't one of those races where you are blocking the rport, but the
IO keeps coming around so the retries are used really quickly right (the
driver looks like it has the fc class and internal state checks to
prevent this but I wanted to make sure).
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