[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>
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 4951aa8..bbea90b 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -26,6 +26,7 @@
#include <asm/ebcdic.h>
#include <asm/idals.h>
#include <asm/itcw.h>
+#include <asm/diag.h>
/* This is ugly... */
#define PRINTK_HEADER "dasd:"
@@ -2212,6 +2213,13 @@
goto out;
}
+ if ((mode & FMODE_WRITE) &&
+ (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
+ (base->features & DASD_FEATURE_READONLY))) {
+ rc = -EROFS;
+ goto out;
+ }
+
return 0;
out:
@@ -2289,6 +2297,34 @@
* SECTION: common functions for ccw_driver use
*/
+/*
+ * Is the device read-only?
+ * Note that this function does not report the setting of the
+ * readonly device attribute, but how it is configured in z/VM.
+ */
+int dasd_device_is_ro(struct dasd_device *device)
+{
+ struct ccw_dev_id dev_id;
+ struct diag210 diag_data;
+ int rc;
+
+ if (!MACHINE_IS_VM)
+ return 0;
+ ccw_device_get_id(device->cdev, &dev_id);
+ memset(&diag_data, 0, sizeof(diag_data));
+ diag_data.vrdcdvno = dev_id.devno;
+ diag_data.vrdclen = sizeof(diag_data);
+ rc = diag210(&diag_data);
+ if (rc == 0 || rc == 2) {
+ return diag_data.vrdcvfla & 0x80;
+ } else {
+ DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
+ dev_id.devno, rc);
+ return 0;
+ }
+}
+EXPORT_SYMBOL_GPL(dasd_device_is_ro);
+
static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
{
struct ccw_device *cdev = data;