block/iscsi: fix deadlock on scsi check condition

the retry logic was broken because the complete status
of the task structure was not reset. this resulted in
an infinite loop retrying the command over and over.

CC: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

block/iscsi.c

@@ -145,12 +145,13 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
 
     if (iTask->retries-- > 0 && status == SCSI_STATUS_CHECK_CONDITION
         && task->sense.key == SCSI_SENSE_UNIT_ATTENTION) {
+        error_report("iSCSI CheckCondition: %s", iscsi_get_error(iscsi));
         iTask->do_retry = 1;
         goto out;
     }
 
     if (status != SCSI_STATUS_GOOD) {
-        error_report("iSCSI: Failure. %s", iscsi_get_error(iscsi));
+        error_report("iSCSI Failure: %s", iscsi_get_error(iscsi));
     }
 
 out:
@@ -325,6 +326,7 @@ static int coroutine_fn iscsi_co_writev(BlockDriverState *bs,
     }
 
     if (iTask.do_retry) {
+        iTask.complete = 0;
         goto retry;
     }
 
@@ -399,6 +401,7 @@ static int coroutine_fn iscsi_co_readv(BlockDriverState *bs,
     }
 
     if (iTask.do_retry) {
+        iTask.complete = 0;
         goto retry;
     }
 
@@ -433,6 +436,7 @@ static int coroutine_fn iscsi_co_flush(BlockDriverState *bs)
     }
 
     if (iTask.do_retry) {
+        iTask.complete = 0;
         goto retry;
     }
 
@@ -683,6 +687,7 @@ static int64_t coroutine_fn iscsi_co_get_block_status(BlockDriverState *bs,
             scsi_free_scsi_task(iTask.task);
             iTask.task = NULL;
         }
+        iTask.complete = 0;
         goto retry;
     }
 
@@ -767,6 +772,7 @@ coroutine_fn iscsi_co_discard(BlockDriverState *bs, int64_t sector_num,
     }
 
     if (iTask.do_retry) {
+        iTask.complete = 0;
         goto retry;
     }
 
@@ -836,6 +842,7 @@ coroutine_fn iscsi_co_write_zeroes(BlockDriverState *bs, int64_t sector_num,
     }
 
     if (iTask.do_retry) {
+        iTask.complete = 0;
         goto retry;
     }