>  git-scsi-misc.patch

Apologies for not looking into the problem earlier. See
http://marc.info/?t=119628022300005&r=1&w=2
"2.6.24-rc3-mm2: Result: hostbyte=0x01 driverbyte=0x00\nend_request: I/O error"
for previous installment.

I've bisected it to the following patch in git-scsi-misc branch.
Revert on top of 2.6.24-rc4-mm1 also helps.

commit 8655a546c83fc43f0a73416bbd126d02de7ad6c0
Author: Hannes Reinecke <[EMAIL PROTECTED]>
Date:   Tue Nov 6 09:23:40 2007 +0100

    [SCSI] Do not requeue requests if REQ_FAILFAST is set
    
    Any requests with the REQ_FAILFAST flag set should not be requeued
    to the requeust queue, but rather terminated directly.
    Otherwise the multipath failover will stall until the command
    timeout triggers.
    
    Signed-off-by: Hannes Reinecke <[EMAIL PROTECTED]>
    Signed-off-by: James Bottomley <[EMAIL PROTECTED]>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0f44bdb..0da0dd0 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1286,6 +1286,11 @@ int scsi_prep_state_check(struct scsi_device *sdev, 
struct request *req)
                         */
                        if (!(req->cmd_flags & REQ_PREEMPT))
                                ret = BLKPREP_DEFER;
+                       /*
+                        * Return failfast requests immediately
+                        */
+                       if (req->cmd_flags & REQ_FAILFAST)
+                               ret = BLKPREP_KILL;
                        break;
                default:
                        /*
@@ -1414,6 +1419,17 @@ static inline int scsi_host_queue_ready(struct 
request_queue *q,
        return 1;
 }
 
+static void __scsi_kill_request(struct request *req)
+{
+       struct scsi_cmnd *cmd = req->special;
+       struct scsi_device *sdev = cmd->device;
+
+       cmd->result = DID_NO_CONNECT << 16;
+       atomic_inc(&cmd->device->iorequest_cnt);
+       sdev->device_busy--;
+       __scsi_done(cmd);
+}
+
 /*
  * Kill a request for a dead device
  */
@@ -1527,8 +1543,16 @@ static void scsi_request_fn(struct request_queue *q)
                 * accept it.
                 */
                req = elv_next_request(q);
-               if (!req || !scsi_dev_queue_ready(q, sdev))
+               if (!req)
+                       break;
+
+               if (!scsi_dev_queue_ready(q, sdev)) {
+                       if (req->cmd_flags & REQ_FAILFAST) {
+                               scsi_kill_request(req, q);
+                               continue;
+                       }
                        break;
+               }
 
                if (unlikely(!scsi_device_online(sdev))) {
                        sdev_printk(KERN_ERR, sdev,
@@ -1609,8 +1633,12 @@ static void scsi_request_fn(struct request_queue *q)
         * later time.
         */
        spin_lock_irq(q->queue_lock);
-       blk_requeue_request(q, req);
-       sdev->device_busy--;
+       if (unlikely(req->cmd_flags & REQ_FAILFAST))
+               __scsi_kill_request(req);
+       else {
+               blk_requeue_request(q, req);
+               sdev->device_busy--;
+       }
        if(sdev->device_busy == 0)
                blk_plug_device(q);
  out:
--
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