[S390] dasd: automatic recognition of read-only devices

In z/VM it is possible to attach a device as read-only. To prevent
unintentional write requests and subsequent I/O errors, we can detect
this configuration using the z/VM DIAG 210 interface and set the
respective linux block device to read-only as well.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index d7163f904f40..01f4e7a34aa8 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1089,6 +1089,7 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
         struct dasd_eckd_private *private;
         struct dasd_block *block;
         int is_known, rc;
+        int readonly;
 
         if (!ccw_device_is_pathgroup(device->cdev)) {
                 dev_warn(&device->cdev->dev,
@@ -1182,15 +1183,20 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
         else
                 private->real_cyl = private->rdc_data.no_cyl;
 
+        readonly = dasd_device_is_ro(device);
+        if (readonly)
+                set_bit(DASD_FLAG_DEVICE_RO, &device->flags);
+
         dev_info(&device->cdev->dev, "New DASD %04X/%02X (CU %04X/%02X) "
-                 "with %d cylinders, %d heads, %d sectors\n",
+                 "with %d cylinders, %d heads, %d sectors%s\n",
                  private->rdc_data.dev_type,
                  private->rdc_data.dev_model,
                  private->rdc_data.cu_type,
                  private->rdc_data.cu_model.model,
                  private->real_cyl,
                  private->rdc_data.trk_per_cyl,
-                 private->rdc_data.sec_per_trk);
+                 private->rdc_data.sec_per_trk,
+                 readonly ? ", read-only device" : "");
         return 0;
 
 out_err3: