Bug#14324766:PARTIALLY WRITTEN INSERT STATEMENT IN BINLOG

NO ERRORS REPORTED
      
Problem:
=======
Errors from my_b_fill are ignored. MYSQL_BIN_LOG::write_cache
code assumes that 0 returned from my_b_fill always means
end-of-cache, but that is incorrect. It can result in error
and the error is ignored. Other callers of my_b_fill don't
check for error: my_b_copy_to_file, maybe my_b_gets.
      
Fix:
===
An error handler is already present to check the "cache"
error that is reported during "MYSQL_BIN_LOG::write_cache"
call. Hence error handlers are added for "my_b_copy_to_file"
and "my_b_gets".
During my_b_fill() function call, when the cache read fails
info->error= -1 is set. Hence a check for "info->error"
is added for the above to callers upon their return.

mysys/mf_iocache2.c:
  Added a check for "cache->error" and simulation of cache read failure
mysys/my_read.c:
  Simulation of read failure
sql/log_event.cc:
  Added debug simulation
sql/sql_repl.cc:
  Added a check for cache error

mysys/mf_iocache2.c

 /*
-   Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -66,6 +66,8 @@ my_b_copy_to_file(IO_CACHE *cache, FILE *file)
       DBUG_RETURN(1);
     cache->read_pos= cache->read_end;
   } while ((bytes_in_cache= my_b_fill(cache)));
+  if(cache->error == -1)
+    DBUG_RETURN(1);
   DBUG_RETURN(0);
 }
 
@@ -215,6 +217,8 @@ size_t my_b_fill(IO_CACHE *info)
     info->error= 0;
     return 0;					/* EOF */
   }
+  DBUG_EXECUTE_IF ("simulate_my_b_fill_error",
+                   {DBUG_SET("+d,simulate_file_read_error");});
   if ((length= my_read(info->file,info->buffer,max_length,
                        info->myflags)) == (size_t) -1)
   {

mysys/my_read.c

-/* Copyright (c) 2000-2002, 2004, 2006, 2007 MySQL AB
+/* Copyright (c) 2000-2002, 2004, 2006, 2007, 2013 MySQL AB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -44,8 +44,18 @@ size_t my_read(File Filedes, uchar *Buffer, size_t Count, myf MyFlags)
   for (;;)
   {
     errno= 0;					/* Linux doesn't reset this */
-    if ((readbytes= read(Filedes, Buffer, (uint) Count)) != Count)
+    if (DBUG_EVALUATE_IF("simulate_file_read_error", 1, 0) ||
+        (readbytes= read(Filedes, Buffer, (uint) Count)) != Count)
     {
+      DBUG_EXECUTE_IF ("simulate_file_read_error",
+                       {
+                         errno= ENOSPC;
+                         readbytes= (size_t) -1;
+                         DBUG_SET("-d,simulate_file_read_error");
+                         DBUG_SET("-d,simulate_my_b_fill_error");
+                       });
+
+
       my_errno= errno ? errno : -1;
       DBUG_PRINT("warning",("Read only %d bytes off %lu from %d, errno: %d",
                             (int) readbytes, (ulong) Count, Filedes,

sql/log_event.cc

@@ -9196,6 +9196,8 @@ Write_rows_log_event::do_exec_row(const Relay_log_info *const rli)
 #ifdef MYSQL_CLIENT
 void Write_rows_log_event::print(FILE *file, PRINT_EVENT_INFO* print_event_info)
 {
+  DBUG_EXECUTE_IF("simulate_cache_read_error",
+                  {DBUG_SET("+d,simulate_my_b_fill_error");});
   Rows_log_event::print_helper(file, print_event_info, "Write_rows");
 }
 #endif

sql/sql_repl.cc

@@ -1732,6 +1732,8 @@ bool show_binlogs(THD* thd)
     if (protocol->write())
       goto err;
   }
+  if(index_file->error == -1)
+    goto err;
   mysql_bin_log.unlock_index();
   my_eof(thd);
   DBUG_RETURN(FALSE);