The current medium access timeout counter will be increased for
each command, so if there are enough failed commands we'll hit
the medium access timeout for even a single device failure and
the following kernel message is displayed:
sd H:C:T:L: [sdXY] Medium access timeout failure. Offlining disk!
Fix this by making the timeout per EH run, ie the counter will
only be increased once per device and EH run.
Fixes: 18a4d0a ("[SCSI] Handle disk devices which can not process medium access commands")
Cc: Ewan Milne <emilne@xxxxxxxxxx>
Cc: Lawrence Obermann <loberman@xxxxxxxxxx>
Cc: Benjamin Block <bblock@xxxxxxxxxxxxxxxxxx>
Cc: Steffen Maier <maier@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Hannes Reinecke <hare@xxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/scsi/scsi_error.c | 18 ++++++++++++++++++
drivers/scsi/sd.c | 27 ++++++++++++++++++++++++++-
drivers/scsi/sd.h | 1 +
include/scsi/scsi_driver.h | 1 +
4 files changed, 46 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index f2cafae..370f6c0 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -221,6 +221,23 @@ static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
}
/**
+ * scsi_eh_reset - call into ->eh_action to reset internal counters
+ * @scmd: scmd to run eh on.
+ *
+ * The scsi driver might be carrying internal state about the
+ * devices, so we need to call into the driver to reset the
+ * internal state once the error handler is started.
+ */
+static void scsi_eh_reset(struct scsi_cmnd *scmd)
+{
+ if (!blk_rq_is_passthrough(scmd->request)) {
+ struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
+ if (sdrv->eh_reset)
+ sdrv->eh_reset(scmd);
+ }
+}
+
+/**
* scsi_eh_scmd_add - add scsi cmd to error handling.
* @scmd: scmd to run eh on.
* @eh_flag: optional SCSI_EH flag.
@@ -249,6 +266,7 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
eh_flag &= ~SCSI_EH_CANCEL_CMD;
scmd->eh_eflags |= eh_flag;
+ scsi_eh_reset(scmd);
list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
shost->host_failed++;
scsi_eh_wakeup(shost);
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index d277e86..bd2a38e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -115,6 +115,7 @@
static int sd_init_command(struct scsi_cmnd *SCpnt);
static void sd_uninit_command(struct scsi_cmnd *SCpnt);
static int sd_done(struct scsi_cmnd *);
+static void sd_eh_reset(struct scsi_cmnd *);
static int sd_eh_action(struct scsi_cmnd *, int);
static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
static void scsi_disk_release(struct device *cdev);
@@ -532,6 +533,7 @@ static void sd_set_flush_flag(struct scsi_disk *sdkp)
.uninit_command = sd_uninit_command,
.done = sd_done,
.eh_action = sd_eh_action,
+ .eh_reset = sd_eh_reset,
};
/*
@@ -1686,6 +1688,26 @@ static int sd_pr_clear(struct block_device *bdev, u64 key)
};
/**
+ * sd_eh_reset - reset error handling callback
+ * @scmd: sd-issued command that has failed
+ *
+ * This function is called by the SCSI midlayer before starting
+ * SCSI EH. When counting medium access failures we have to be
+ * careful to register it only only once per device and SCSI EH run;
+ * there might be several timed out commands which will cause the
+ * 'max_medium_access_timeouts' counter to trigger after the first
+ * SCSI EH run already and set the device to offline.
+ * So this function resets the internal counter before starting SCSI EH.
+ **/
+static void sd_eh_reset(struct scsi_cmnd *scmd)
+{
+ struct scsi_disk *sdkp = scsi_disk(scmd->request->rq_disk);
+
+ /* New SCSI EH run, reset gate variable */
+ sdkp->ignore_medium_access_errors = false;
+}
+
+/**
* sd_eh_action - error handling callback
* @scmd: sd-issued command that has failed
* @eh_disp: The recovery disposition suggested by the midlayer
@@ -1714,7 +1736,10 @@ static int sd_eh_action(struct scsi_cmnd *scmd, int eh_disp)
* process of recovering or has it suffered an internal failure
* that prevents access to the storage medium.
*/
- sdkp->medium_access_timed_out++;
+ if (!sdkp->ignore_medium_access_errors) {
+ sdkp->medium_access_timed_out++;
+ sdkp->ignore_medium_access_errors = true;
+ }
/*
* If the device keeps failing read/write commands but TEST UNIT
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 4dac35e..0cf9680 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -106,6 +106,7 @@ struct scsi_disk {
unsigned rc_basis: 2;
unsigned zoned: 2;
unsigned urswrz : 1;
+ unsigned ignore_medium_access_errors : 1;
};
#define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)
diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
index 891a658..a5534cc 100644
--- a/include/scsi/scsi_driver.h
+++ b/include/scsi/scsi_driver.h
@@ -16,6 +16,7 @@ struct scsi_driver {
void (*uninit_command)(struct scsi_cmnd *);
int (*done)(struct scsi_cmnd *);
int (*eh_action)(struct scsi_cmnd *, int);
+ void (*eh_reset)(struct scsi_cmnd *);
};
#define to_scsi_driver(drv) \
container_of((drv), struct scsi_driver, gendrv)
--
1.8.5.6
