s390/dasd: Handle out-of-space constraint

The storage server issues three different types of out-of-space messages
whenever the Extent Pool or Extent Repository space runs short. When a
configured warning watermark is reached, the physical space is
completeley exhausted, or the capacity constraints have been relieved, a
message is received.

A log entry for the sysadmin to react to is generated in any case. In
case the physical space is completely exhausted, sense data that reads
"no space left on device" is received. In this case, currently running
I/O will be blocked until space has either been released or added to the
extent pool, and a relieve message was received via an attention
interrupt.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h
index 13112ba9f93f..6943508d0f1d 100644
--- a/drivers/s390/block/dasd_eckd.h
+++ b/drivers/s390/block/dasd_eckd.h
@@ -90,10 +90,22 @@
 #define CUIR_RESUME			 0x02
 
 /*
+ * Out-of-space (OOS) Codes
+ */
+#define REPO_WARN			 0x01
+#define REPO_EXHAUST			 0x02
+#define POOL_WARN			 0x03
+#define POOL_EXHAUST			 0x04
+#define REPO_RELIEVE			 0x05
+#define POOL_RELIEVE			 0x06
+
+/*
  * attention message definitions
  */
 #define ATTENTION_LENGTH_CUIR		 0x0e
 #define ATTENTION_FORMAT_CUIR		 0x01
+#define ATTENTION_LENGTH_OOS		 0x10
+#define ATTENTION_FORMAT_OOS		 0x06
 
 #define DASD_ECKD_PG_GROUPED		 0x10
 
@@ -449,6 +461,17 @@ struct dasd_rssd_lcq {
 	struct dasd_ext_pool_sum ext_pool_sum[448];
 } __packed;
 
+struct dasd_oos_message {
+	__u16 length;
+	__u8 format;
+	__u8 code;
+	__u8 percentage_empty;
+	__u8 reserved;
+	__u16 ext_pool_id;
+	__u16 token;
+	__u8 unused[6];
+} __packed;
+
 struct dasd_cuir_message {
 	__u16 length;
 	__u8 format;