iscsi: Translate scsi sense into error code

Previously we return -EIO blindly when anything goes wrong. Add a helper
function to parse sense fields and try to make the return code more
meaningful.

This also fixes the default werror configuration (enospc) when we're
using qcow2 on an iscsi lun. The old -EIO not being treated as out of
space error failed to trigger vm stop.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <1446699609-11376-1-git-send-email-famz@redhat.com>
[libiscsi 1.9 compatibility - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 73 insertions, 20 deletions

diff --git a/block/iscsi.c b/block/iscsi.c
index 9a628b7..080ef52 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -84,6 +84,7 @@ typedef struct IscsiTask {
     IscsiLun *iscsilun;
     QEMUTimer retry_timer;
     bool force_next_flush;
+    int err_code;
 } IscsiTask;
 
 typedef struct IscsiAIOCB {
@@ -169,19 +170,70 @@ static inline unsigned exp_random(double mean)
     return -mean * log((double)rand() / RAND_MAX);
 }
 
-/* SCSI_STATUS_TASK_SET_FULL and SCSI_STATUS_TIMEOUT were introduced
- * in libiscsi 1.10.0 as part of an enum. The LIBISCSI_API_VERSION
- * macro was introduced in 1.11.0. So use the API_VERSION macro as
- * a hint that the macros are defined and define them ourselves
- * otherwise to keep the required libiscsi version at 1.9.0 */
-#if !defined(LIBISCSI_API_VERSION)
-#define QEMU_SCSI_STATUS_TASK_SET_FULL  0x28
-#define QEMU_SCSI_STATUS_TIMEOUT        0x0f000002
-#else
-#define QEMU_SCSI_STATUS_TASK_SET_FULL  SCSI_STATUS_TASK_SET_FULL
-#define QEMU_SCSI_STATUS_TIMEOUT        SCSI_STATUS_TIMEOUT
+/* SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST was introduced in
+ * libiscsi 1.10.0, together with other constants we need.  Use it as
+ * a hint that we have to define them ourselves if needed, to keep the
+ * minimum required libiscsi version at 1.9.0.  We use an ASCQ macro for
+ * the test because SCSI_STATUS_* is an enum.
+ *
+ * To guard against future changes where SCSI_SENSE_ASCQ_* also becomes
+ * an enum, check against the LIBISCSI_API_VERSION macro, which was
+ * introduced in 1.11.0.  If it is present, there is no need to define
+ * anything.
+ */
+#if !defined(SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST) && \
+    !defined(LIBISCSI_API_VERSION)
+#define SCSI_STATUS_TASK_SET_FULL                          0x28
+#define SCSI_STATUS_TIMEOUT                                0x0f000002
+#define SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST    0x2600
+#define SCSI_SENSE_ASCQ_PARAMETER_LIST_LENGTH_ERROR        0x1a00
 #endif
 
+static int iscsi_translate_sense(struct scsi_sense *sense)
+{
+    int ret;
+
+    switch (sense->key) {
+    case SCSI_SENSE_NOT_READY:
+        return -EBUSY;
+    case SCSI_SENSE_DATA_PROTECTION:
+        return -EACCES;
+    case SCSI_SENSE_COMMAND_ABORTED:
+        return -ECANCELED;
+    case SCSI_SENSE_ILLEGAL_REQUEST:
+        /* Parse ASCQ */
+        break;
+    default:
+        return -EIO;
+    }
+    switch (sense->ascq) {
+    case SCSI_SENSE_ASCQ_PARAMETER_LIST_LENGTH_ERROR:
+    case SCSI_SENSE_ASCQ_INVALID_OPERATION_CODE:
+    case SCSI_SENSE_ASCQ_INVALID_FIELD_IN_CDB:
+    case SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST:
+        ret = -EINVAL;
+        break;
+    case SCSI_SENSE_ASCQ_LBA_OUT_OF_RANGE:
+        ret = -ENOSPC;
+        break;
+    case SCSI_SENSE_ASCQ_LOGICAL_UNIT_NOT_SUPPORTED:
+        ret = -ENOTSUP;
+        break;
+    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT:
+    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT_TRAY_CLOSED:
+    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT_TRAY_OPEN:
+        ret = -ENOMEDIUM;
+        break;
+    case SCSI_SENSE_ASCQ_WRITE_PROTECTED:
+        ret = -EACCES;
+        break;
+    default:
+        ret = -EIO;
+        break;
+    }
+    return ret;
+}
+
 static void
 iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
                         void *command_data, void *opaque)
@@ -203,11 +255,11 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
                 goto out;
             }
             if (status == SCSI_STATUS_BUSY ||
-                status == QEMU_SCSI_STATUS_TIMEOUT ||
-                status == QEMU_SCSI_STATUS_TASK_SET_FULL) {
+                status == SCSI_STATUS_TIMEOUT ||
+                status == SCSI_STATUS_TASK_SET_FULL) {
                 unsigned retry_time =
                     exp_random(iscsi_retry_times[iTask->retries - 1]);
-                if (status == QEMU_SCSI_STATUS_TIMEOUT) {
+                if (status == SCSI_STATUS_TIMEOUT) {
                     /* make sure the request is rescheduled AFTER the
                      * reconnect is initiated */
                     retry_time = EVENT_INTERVAL * 2;
@@ -226,6 +278,7 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
                 return;
             }
         }
+        iTask->err_code = iscsi_translate_sense(&task->sense);
         error_report("iSCSI Failure: %s", iscsi_get_error(iscsi));
     } else {
         iTask->iscsilun->force_next_flush |= iTask->force_next_flush;
@@ -455,7 +508,7 @@ retry:
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
-        return -EIO;
+        return iTask.err_code;
     }
 
     iscsi_allocationmap_set(iscsilun, sector_num, nb_sectors);
@@ -644,7 +697,7 @@ retry:
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
-        return -EIO;
+        return iTask.err_code;
     }
 
     return 0;
@@ -683,7 +736,7 @@ retry:
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
-        return -EIO;
+        return iTask.err_code;
     }
 
     return 0;
@@ -703,7 +756,7 @@ iscsi_aio_ioctl_cb(struct iscsi_context *iscsi, int status,
     if (status < 0) {
         error_report("Failed to ioctl(SG_IO) to iSCSI lun. %s",
                      iscsi_get_error(iscsi));
-        acb->status = -EIO;
+        acb->status = iscsi_translate_sense(&acb->task->sense);
     }
 
     acb->ioh->driver_status = 0;
@@ -905,7 +958,7 @@ retry:
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
-        return -EIO;
+        return iTask.err_code;
     }
 
     iscsi_allocationmap_clear(iscsilun, sector_num, nb_sectors);
@@ -999,7 +1052,7 @@ retry:
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
-        return -EIO;
+        return iTask.err_code;
     }
 
     if (flags & BDRV_REQ_MAY_UNMAP) {