Hi,
below is a patch introducing device recovery, trying to prevent i/o errors
when a DID_NO_CONNECT or SOFT_ERROR does happen.
The patch still needs quite some work:
1.) I still didn't figure out what is the best place to run
sdev->deh.ehandler = kthread_run(scsi_device_error_handler, ...)
2.) As I see it, its not a good idea to run spi_schedule_dv_device() in
scsi_error.c, since spi_schedule_dv_device() is in scsi_transport_spi.c,
which seems to be separated from the core scsi-layer.
So what is another way to initiate a DV in scsi_error.c?
3.) Maybe related to 2), for now I'm calling spi_schedule_dv_device(), but
this is not always doing what I want.
[ 406.785104] sd 5:0:2:0: deh: scheduling domain validation
[ 408.422530] target5:0:2: Beginning Domain Validation
[ 408.466620] target5:0:2: Domain Validation skipping write tests
[ 408.472771] target5:0:2: Ending Domain Validation
Hmm, somehow related to sdev->inquiry_len, but isn't it the task of
spi_schedule_dv_device() and subfunctions to do that properly?
Any comments, hints and help is appreciated.
Signed-of-by: Bernd Schubert <bs@xxxxxxxxx>
Index: linux-2.6.22/drivers/scsi/scsi_error.c
===================================================================
--- linux-2.6.22.orig/drivers/scsi/scsi_error.c 2007-12-12 12:26:20.000000000
+0100
+++ linux-2.6.22/drivers/scsi/scsi_error.c 2007-12-12 13:08:40.000000000 +0100
@@ -33,6 +33,7 @@
#include <scsi/scsi_transport.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>
+#include <scsi/scsi_transport_spi.h>
#include "scsi_priv.h"
#include "scsi_logging.h"
@@ -1589,6 +1590,153 @@ int scsi_error_handler(void *data)
return 0;
}
+/**
+ * scsi_unjam_sdev - try to revover a failed scsi-device
+ * @sdev: scsi device we are recovering
+ */
+static int scsi_unjam_sdev(struct scsi_device *sdev)
+{
+ int rtn;
+
+ sdev_printk(KERN_CRIT, sdev, "resetting device\n");
+ rtn = scsi_reset_provider(sdev, SCSI_TRY_RESET_DEVICE);
+ scsi_report_device_reset(sdev->host, sdev->channel, sdev->id);
+ if (rtn == SUCCESS)
+ sdev_printk(KERN_INFO, sdev, "device reset succeeded, "
+ "set device to running state\n");
+ return SUCCESS;
+}
+
+/**
+ * scsi_schedule_deh - schedule EH for SCSI device
+ * @sdev: SCSI device to invoke error handling on.
+ *
+ **/
+void scsi_schedule_deh(struct scsi_device *sdev)
+{
+#if 0
+ if (sdev->deh.error) {
+ /* blocking the device does not work! another recovery was
+ * scheduled, though no i/o should go to the device now! */
+ sdev_printk(KERN_CRIT, sdev,
+ "device already in recovery, but another recovery "
+ "was scheduled\n");
+ dump_stack();
+ }
+#endif
+ if (sdev->deh.error)
+ return; /* recovery already running */
+
+ if (sdev->deh.last_recovery
+ && jiffies < sdev->deh.last_recovery + 300 * HZ)
+ sdev->deh.count++;
+ else
+ sdev->deh.count = 0;
+
+ if (sdev->deh.count >= 10) {
+ sdev_printk(KERN_WARNING, sdev,
+ "too many errors within time limit, setting "
+ "device offline\n");
+ scsi_device_set_state(sdev, SDEV_OFFLINE);
+ return;
+ } else if (sdev->deh.count >= 5) {
+ sdev_printk(KERN_INFO, sdev, "Initiating host recovery\n");
+ scsi_schedule_eh(sdev->host); /* host recovery */
+ return;
+ } else
+ sdev->deh.count++;
+
+ sdev_printk(KERN_INFO, sdev, "n-error: %d\n", sdev->deh.count);
+
+ if (!scsi_internal_device_block(sdev)) {
+ sdev->deh.error = 1;
+ if (sdev->deh.ehandler)
+ wake_up_process(sdev->deh.ehandler);
+ else
+ sdev_printk(KERN_WARNING, sdev,
+ "deh handler missing\n");
+ } else {
+ sdev_printk(KERN_WARNING, sdev,
+ "Couldn't block device, calling host recovery\n");
+ scsi_schedule_eh(sdev->host);
+ }
+}
+EXPORT_SYMBOL_GPL(scsi_schedule_deh);
+
+/**
+ * scsi_device_error_handler - SCSI error handler thread
+ * @data: Device for which we are running.
+ *
+ * Notes:
+ * This is the main device error handling loop. This is run as a kernel
thread
+ * for every SCSI device and handles all device error handling activity.
+ **/
+int scsi_device_error_handler(void *data)
+{
+ struct scsi_device *sdev = data;
+ int sleeptime = 30;
+
+ current->flags |= PF_NOFREEZE;
+
+ /*
+ * We use TASK_INTERRUPTIBLE so that the thread is not
+ * counted against the load average as a running process.
+ * We never actually get interrupted because kthread_run
+ * disables singal delivery for the created thread.
+ */
+ set_current_state(TASK_INTERRUPTIBLE);
+ while (!kthread_should_stop()) {
+ if (sdev->deh.error == 0) {
+ SCSI_LOG_ERROR_RECOVERY(1,
+ printk("Error handler scsi_deh sleeping\n"));
+ schedule();
+ set_current_state(TASK_INTERRUPTIBLE);
+ continue;
+ }
+
+ __set_current_state(TASK_RUNNING);
+ SCSI_LOG_ERROR_RECOVERY(1,
+ printk("Error handler scsi_deh waking up\n"));
+
+ sdev_printk(KERN_CRIT, sdev, "waiting %ds to settle device\n",
+ sleeptime);
+ msleep (sleeptime * 1000);
+
+ if (sdev->deh.count < 2) {
+ sdev_printk(KERN_WARNING, sdev,
+ "First device error, simply recovery\n");
+ goto cont;
+ }
+
+ /*
+ * We have a device that is failing for some reason. Figure out
+ * what we need to do to get it up and online again (if we can).
+ * If we fail, we call host recovery
+ */
+ if (scsi_unjam_sdev(sdev) != SUCCESS) {
+ sdev_printk(KERN_CRIT, sdev, "device recovery failed,"
+ " initiating host recovery\n");
+ scsi_schedule_eh(sdev->host);
+ /* scsi_schedule_eh() doesn't know about deh.error */
+ goto error_cont;
+ }
+cont:
+ if (scsi_internal_device_unblock(sdev))
+ sdev_printk(KERN_WARNING, sdev,
+ "deh: device unblocking failed!\n");
+ spi_schedule_dv_device(sdev);
+error_cont:
+ sdev->deh.error = 0;
+ sdev->deh.last_recovery = jiffies;
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+ __set_current_state(TASK_RUNNING);
+
+ sdev_printk(KERN_CRIT, sdev, "Error handler scsi_deh exiting\n");
+ sdev->deh.ehandler = NULL;
+ return 0;
+}
+
/*
* Function: scsi_report_bus_reset()
*
Index: linux-2.6.22/include/scsi/scsi_device.h
===================================================================
--- linux-2.6.22.orig/include/scsi/scsi_device.h 2007-12-12 12:26:20.000000000
+0100
+++ linux-2.6.22/include/scsi/scsi_device.h 2007-12-12 12:26:23.000000000
+0100
@@ -145,6 +145,13 @@ struct scsi_device {
enum scsi_device_state sdev_state;
unsigned long sdev_data[0];
+
+ struct device_error_handler {
+ unsigned error;
+ struct task_struct * ehandler; /* Error recovery thread. */
+ time_t last_recovery; /* time on last error recovery */
+ unsigned count; /* error count */
+ } deh;
} __attribute__((aligned(sizeof(unsigned long))));
#define to_scsi_device(d) \
container_of(d, struct scsi_device, sdev_gendev)
Index: linux-2.6.22/drivers/scsi/scsi_scan.c
===================================================================
--- linux-2.6.22.orig/drivers/scsi/scsi_scan.c 2007-12-12 12:26:20.000000000
+0100
+++ linux-2.6.22/drivers/scsi/scsi_scan.c 2007-12-12 12:26:23.000000000 +0100
@@ -1313,6 +1313,12 @@ static int scsi_report_lun_scan(struct s
return 0;
}
+ if (!sdev->deh.ehandler)
+ sdev->deh.ehandler = kthread_run(scsi_device_error_handler,
+ sdev, "sdeh_%d_%d_%d_%d",
+ shost->host_no, sdev->channel,
+ sdev->id, sdev->lun);
+
sprintf(devname, "host %d channel %d id %d",
shost->host_no, sdev->channel, sdev->id);
@@ -1489,8 +1495,13 @@ struct scsi_device *__scsi_add_device(st
scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
mutex_unlock(&shost->scan_mutex);
scsi_target_reap(starget);
- put_device(&starget->dev);
+ if (!sdev->deh.ehandler)
+ sdev->deh.ehandler = kthread_run(scsi_device_error_handler,
+ sdev, "sdeh_%d_%d_%d_%d",
+ shost->host_no, sdev->channel,
+ sdev->id, sdev->lun);
+ put_device(&starget->dev);
return sdev;
}
EXPORT_SYMBOL(__scsi_add_device);
Index: linux-2.6.22/drivers/scsi/scsi_priv.h
===================================================================
--- linux-2.6.22.orig/drivers/scsi/scsi_priv.h 2007-12-12 12:26:20.000000000
+0100
+++ linux-2.6.22/drivers/scsi/scsi_priv.h 2007-12-12 12:26:23.000000000 +0100
@@ -54,6 +54,7 @@ extern void scsi_add_timer(struct scsi_c
extern int scsi_delete_timer(struct scsi_cmnd *);
extern void scsi_times_out(struct scsi_cmnd *cmd);
extern int scsi_error_handler(void *host);
+extern int scsi_device_error_handler(void *sdev);
extern int scsi_decide_disposition(struct scsi_cmnd *cmd);
extern void scsi_eh_wakeup(struct Scsi_Host *shost);
extern int scsi_eh_scmd_add(struct scsi_cmnd *, int);
Index: linux-2.6.22/drivers/scsi/scsi_sysfs.c
===================================================================
--- linux-2.6.22.orig/drivers/scsi/scsi_sysfs.c 2007-12-12 12:26:20.000000000
+0100
+++ linux-2.6.22/drivers/scsi/scsi_sysfs.c 2007-12-12 12:26:23.000000000 +0100
@@ -10,6 +10,7 @@
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/device.h>
+#include <linux/kthread.h>
#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
@@ -798,6 +799,9 @@ void __scsi_remove_device(struct scsi_de
if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0)
return;
+ if (sdev->deh.ehandler)
+ kthread_stop(sdev->deh.ehandler);
+
class_device_unregister(&sdev->sdev_classdev);
transport_remove_device(dev);
device_del(dev);
Index: linux-2.6.22/drivers/scsi/scsi_lib.c
===================================================================
--- linux-2.6.22.orig/drivers/scsi/scsi_lib.c 2007-12-12 12:26:20.000000000
+0100
+++ linux-2.6.22/drivers/scsi/scsi_lib.c 2007-12-12 12:52:31.000000000 +0100
@@ -28,6 +28,7 @@
#include "scsi_priv.h"
#include "scsi_logging.h"
+#include "scsi_transport_api.h"
#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
@@ -820,6 +821,7 @@ void scsi_io_completion(struct scsi_cmnd
int this_count = cmd->request_bufflen;
request_queue_t *q = cmd->device->request_queue;
struct request *req = cmd->request;
+ struct scsi_device *sdev = cmd->device;
int clear_errors = 1;
struct scsi_sense_hdr sshdr;
int sense_valid = 0;
@@ -958,13 +960,26 @@ void scsi_io_completion(struct scsi_cmnd
break;
}
}
- if (host_byte(result) == DID_RESET) {
+ switch (host_byte(result)) {
+ case DID_OK:
+ break;
+ case DID_RESET:
/* Third party bus reset or reset for error recovery
* reasons. Just retry the request and see what
* happens.
*/
scsi_requeue_command(q, cmd);
return;
+ case DID_NO_CONNECT:
+ sdev_printk(KERN_CRIT, sdev, "DID_NO_CONNECT\n");
+ scsi_schedule_deh(sdev);
+ scsi_requeue_command(q, cmd);
+ return;
+ case DID_SOFT_ERROR:
+ sdev_printk(KERN_CRIT, sdev, "DID_SOFT_ERROR\n");
+ scsi_schedule_deh(sdev);
+ scsi_requeue_command(q, cmd);
+ return;
}
if (result) {
if (!(req->cmd_flags & REQ_QUIET)) {
@@ -2007,18 +2022,18 @@ scsi_device_set_state(struct scsi_device
goto illegal;
}
break;
-
}
sdev->sdev_state = state;
return 0;
illegal:
- SCSI_LOG_ERROR_RECOVERY(1,
+ SCSI_LOG_ERROR_RECOVERY(1,
sdev_printk(KERN_ERR, sdev,
"Illegal state transition %s->%s\n",
scsi_device_state_name(oldstate),
scsi_device_state_name(state))
);
+ dump_stack();
return -EINVAL;
}
EXPORT_SYMBOL(scsi_device_set_state);
Index: linux-2.6.22/drivers/scsi/scsi_transport_api.h
===================================================================
--- linux-2.6.22.orig/drivers/scsi/scsi_transport_api.h 2007-12-12
12:26:20.000000000 +0100
+++ linux-2.6.22/drivers/scsi/scsi_transport_api.h 2007-12-12
12:26:23.000000000 +0100
@@ -2,5 +2,6 @@
#define _SCSI_TRANSPORT_API_H
void scsi_schedule_eh(struct Scsi_Host *shost);
+void scsi_schedule_deh(struct scsi_device *sdev);
#endif /* _SCSI_TRANSPORT_API_H */
Index: linux-2.6.22/drivers/scsi/scsi.c
===================================================================
--- linux-2.6.22.orig/drivers/scsi/scsi.c 2007-12-12 12:26:20.000000000 +0100
+++ linux-2.6.22/drivers/scsi/scsi.c 2007-12-12 12:26:23.000000000 +0100
@@ -494,7 +494,8 @@ int scsi_dispatch_cmd(struct scsi_cmnd *
*/
scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
- SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
+ SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked or "
+ "in recovery\n"));
/*
* NOTE: rtn is still zero here because we don't need the
--
Bernd Schubert
Q-Leap Networks GmbH
-
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