bzr push into mysql-6.0 branch (dlenev:2716 to 2717) Bug#37961

[Dmitry Lenev]

 2717 Dmitry Lenev	2008-10-01
      Fix for bug#37961 "'Trying to destroy unitialized mutex' when
      --datadir does not exist".
      
      Attempt to start server with non-existing data directory led to
      destroying of uninitialized Backup_restore_ctx::run_lock mutex
      and assertion failure. The problem was that unireg_abort() 
      function, which is called in case of error during server
      start-up and which assumes that it can be called even for
      partially initialized server, has called backup_shutdown()
      function which assumed that backup_init() was successfully
      performed prior to its call.
      
      This patch solves problem by ensuring that backup_shutdown()
      can be safely called without prior call to backup_init() and
      thus satisfying assumption made by unireg_abort().
      
      Note that similar problem with LOCK_mdl has been already
      solved by Monty's patch from 2008-08-13 in similar fashion.
      
      No test case is provided since such situation can't be easily
      covered by our test suite.
modified:
  sql/backup/backup_kernel.h
  sql/backup/kernel.cc

 2716 Alexander Nozdrin	2008-09-16
      Revert .bzr-mysql/default.conf changes
modified:
  .bzr-mysql/default.conf

=== modified file 'sql/backup/backup_kernel.h'
--- a/sql/backup/backup_kernel.h	2008-08-08 17:21:31 +0000
+++ b/sql/backup/backup_kernel.h	2008-10-01 10:14:28 +0000
@@ -87,6 +87,11 @@ class Backup_restore_ctx: public backup:
       ongoing backup/restore operation.  If pointer is null, no
       operation is currently running. */
   static Backup_restore_ctx *current_op;
+  /**
+     Indicates if @c run_lock mutex was initialized and thus it should
+     be properly destroyed during shutdown. @sa backup_shutdown().
+   */
+  static bool run_lock_initialized;
   static pthread_mutex_t  run_lock; ///< To guard @c current_op.
 
   /** 

=== modified file 'sql/backup/kernel.cc'
--- a/sql/backup/kernel.cc	2008-09-05 14:16:07 +0000
+++ b/sql/backup/kernel.cc	2008-10-01 10:14:28 +0000
@@ -96,6 +96,7 @@
 int backup_init()
 {
   pthread_mutex_init(&Backup_restore_ctx::run_lock, MY_MUTEX_INIT_FAST);
+  Backup_restore_ctx::run_lock_initialized= TRUE;
   return 0;
 }
 
@@ -104,10 +105,18 @@ int backup_init()
   
   @note This function is called in the server shut-down sequences, just before
   it shuts-down all its plugins.
+
+  @note Due to way in which server's code is organized this function might be
+  called and should work normally even in situation when backup_init() was not
+  called at all.
  */
 void backup_shutdown()
 {
-  pthread_mutex_destroy(&Backup_restore_ctx::run_lock);
+  if (Backup_restore_ctx::run_lock_initialized)
+  {
+    pthread_mutex_destroy(&Backup_restore_ctx::run_lock);
+    Backup_restore_ctx::run_lock_initialized= FALSE;
+  }
 }
 
 /*
@@ -362,6 +371,7 @@ class Mem_allocator
 // static members
 
 Backup_restore_ctx *Backup_restore_ctx::current_op= NULL;
+bool Backup_restore_ctx::run_lock_initialized= FALSE;
 pthread_mutex_t Backup_restore_ctx::run_lock;