Fix btape bug with big blocksizes

there is an overflow when calculating the maximum file size, which leads
to a eof being written to the tape where btape does not expect it.

Then during the read of the data the unexpected eof lets the test fail.

This fix corrects this overflow.

We also set a higher debug level on the block writings in block.c

Fixes #381: btape tests fail on blocksizes > 256k

src/stored/block.c

@@ -503,15 +503,15 @@ bool DCR::write_block_to_dev()
          }
       }
 
-      Dmsg4(100, "writing block of size %d to dev=%s with max_block_size %d and min_block_size %d\n",
+      Dmsg4(400, "writing block of size %d to dev=%s with max_block_size %d and min_block_size %d\n",
                wlen, dev->print_name(), dev->max_block_size, dev->min_block_size);
 
       if (wlen-blen > 0) {
          memset(block->bufp, 0, wlen-blen); /* clear garbage */
       }
    }
 
-   Dmsg4(100, "writing block of size %d to dev=%s with max_block_size %d and min_block_size %d\n",
+   Dmsg4(400, "writing block of size %d to dev=%s with max_block_size %d and min_block_size %d\n",
                wlen, dev->print_name(), dev->max_block_size, dev->min_block_size);
 
 

src/stored/btape.c

@@ -1109,7 +1109,7 @@ static void speed_test()
    }
 }
 
-const int num_recs = 10000;
+const uint64_t num_recs = 10000LL;
 
 static bool write_two_files()
 {
@@ -1125,10 +1125,11 @@ static bool write_two_files()
     * doesn't insert any additional EOF marks
     */
    if (dev->max_block_size) {
-      dev->max_file_size = (uint64_t)2 * (num_recs * dev->max_block_size);
+      dev->max_file_size = 2LL * num_recs * (uint64_t)dev->max_block_size;
    } else {
-      dev->max_file_size = 2 * (num_recs * DEFAULT_BLOCK_SIZE);
+      dev->max_file_size = 2LL * num_recs * (uint64_t)DEFAULT_BLOCK_SIZE;
    }
+   Dmsg1(100, "max_file_size was set to %lld\n", dev->max_file_size);
 
    Pmsg2(-1, _("\n=== Write, rewind, and re-read test ===\n\n"
       "I'm going to write %d records and an EOF\n"