[S390] dasd: improve error recovery for internal I/O
Most of the error conditions reported by a FICON storage server
indicate situations which can be recovered. Sometimes the host just
needs to retry an I/O request, but sometimes the recovery
is more complex and requires the device driver to wait, choose
a different path, etc.
The DASD device driver has a fully featured error recovery
for normal block layer I/O, but not for internal I/O request which
are for example used during the device bring up.
This can lead to situations where the IPL of a system fails because
DASD devices are not properly recognized.
This patch will extend the internal I/O handling to use the existing
error recovery procedures.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index abb2ec8..39ffc84 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -77,6 +77,11 @@
static struct ccw_driver dasd_eckd_driver; /* see below */
+#define INIT_CQR_OK 0
+#define INIT_CQR_UNFORMATTED 1
+#define INIT_CQR_ERROR 2
+
+
/* initial attempt at a probe function. this can be simplified once
* the other detection code is gone */
static int
@@ -749,8 +754,7 @@
cqr->block = NULL;
cqr->expires = 10*HZ;
cqr->lpm = lpm;
- clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
- cqr->retries = 2;
+ cqr->retries = 256;
cqr->buildclk = get_clock();
cqr->status = DASD_CQR_FILLED;
return cqr;
@@ -949,8 +953,7 @@
cqr->startdev = device;
cqr->memdev = device;
cqr->block = NULL;
- clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
- cqr->retries = 5;
+ cqr->retries = 256;
cqr->expires = 10 * HZ;
/* Prepare for Read Subsystem Data */
@@ -1025,6 +1028,7 @@
cqr->startdev = device;
cqr->memdev = device;
cqr->block = NULL;
+ cqr->retries = 256;
cqr->expires = 10*HZ;
cqr->buildclk = get_clock();
cqr->status = DASD_CQR_FILLED;
@@ -1068,6 +1072,7 @@
else
enable_pav = 1;
rc = dasd_eckd_psf_ssc(device, enable_pav);
+
/* may be requested feature is not available on server,
* therefore just report error and go ahead */
private = (struct dasd_eckd_private *) device->private;
@@ -1265,12 +1270,29 @@
cqr->block = NULL;
cqr->startdev = device;
cqr->memdev = device;
- cqr->retries = 0;
+ cqr->retries = 255;
cqr->buildclk = get_clock();
cqr->status = DASD_CQR_FILLED;
return cqr;
}
+/* differentiate between 'no record found' and any other error */
+static int dasd_eckd_analysis_evaluation(struct dasd_ccw_req *init_cqr)
+{
+ char *sense;
+ if (init_cqr->status == DASD_CQR_DONE)
+ return INIT_CQR_OK;
+ else if (init_cqr->status == DASD_CQR_NEED_ERP ||
+ init_cqr->status == DASD_CQR_FAILED) {
+ sense = dasd_get_sense(&init_cqr->irb);
+ if (sense && (sense[1] & SNS1_NO_REC_FOUND))
+ return INIT_CQR_UNFORMATTED;
+ else
+ return INIT_CQR_ERROR;
+ } else
+ return INIT_CQR_ERROR;
+}
+
/*
* This is the callback function for the init_analysis cqr. It saves
* the status of the initial analysis ccw before it frees it and kicks
@@ -1278,21 +1300,20 @@
* dasd_eckd_do_analysis again (if the devices has not been marked
* for deletion in the meantime).
*/
-static void
-dasd_eckd_analysis_callback(struct dasd_ccw_req *init_cqr, void *data)
+static void dasd_eckd_analysis_callback(struct dasd_ccw_req *init_cqr,
+ void *data)
{
struct dasd_eckd_private *private;
struct dasd_device *device;
device = init_cqr->startdev;
private = (struct dasd_eckd_private *) device->private;
- private->init_cqr_status = init_cqr->status;
+ private->init_cqr_status = dasd_eckd_analysis_evaluation(init_cqr);
dasd_sfree_request(init_cqr, device);
dasd_kick_device(device);
}
-static int
-dasd_eckd_start_analysis(struct dasd_block *block)
+static int dasd_eckd_start_analysis(struct dasd_block *block)
{
struct dasd_eckd_private *private;
struct dasd_ccw_req *init_cqr;
@@ -1304,27 +1325,44 @@
init_cqr->callback = dasd_eckd_analysis_callback;
init_cqr->callback_data = NULL;
init_cqr->expires = 5*HZ;
+ /* first try without ERP, so we can later handle unformatted
+ * devices as special case
+ */
+ clear_bit(DASD_CQR_FLAGS_USE_ERP, &init_cqr->flags);
+ init_cqr->retries = 0;
dasd_add_request_head(init_cqr);
return -EAGAIN;
}
-static int
-dasd_eckd_end_analysis(struct dasd_block *block)
+static int dasd_eckd_end_analysis(struct dasd_block *block)
{
struct dasd_device *device;
struct dasd_eckd_private *private;
struct eckd_count *count_area;
unsigned int sb, blk_per_trk;
int status, i;
+ struct dasd_ccw_req *init_cqr;
device = block->base;
private = (struct dasd_eckd_private *) device->private;
status = private->init_cqr_status;
private->init_cqr_status = -1;
- if (status != DASD_CQR_DONE) {
- dev_warn(&device->cdev->dev,
- "The DASD is not formatted\n");
+ if (status == INIT_CQR_ERROR) {
+ /* try again, this time with full ERP */
+ init_cqr = dasd_eckd_analysis_ccw(device);
+ dasd_sleep_on(init_cqr);
+ status = dasd_eckd_analysis_evaluation(init_cqr);
+ dasd_sfree_request(init_cqr, device);
+ }
+
+ if (status == INIT_CQR_UNFORMATTED) {
+ dev_warn(&device->cdev->dev, "The DASD is not formatted\n");
return -EMEDIUMTYPE;
+ } else if (status == INIT_CQR_ERROR) {
+ dev_err(&device->cdev->dev,
+ "Detecting the DASD disk layout failed because "
+ "of an I/O error\n");
+ return -EIO;
}
private->uses_cdl = 1;
@@ -1616,8 +1654,7 @@
}
fcp->startdev = device;
fcp->memdev = device;
- clear_bit(DASD_CQR_FLAGS_USE_ERP, &fcp->flags);
- fcp->retries = 5; /* set retry counter to enable default ERP */
+ fcp->retries = 256;
fcp->buildclk = get_clock();
fcp->status = DASD_CQR_FILLED;
return fcp;
@@ -2699,6 +2736,7 @@
cqr->startdev = device;
cqr->memdev = device;
cqr->retries = 0;
+ clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
cqr->expires = 10 * HZ;
/* Prepare for Read Subsystem Data */