diff -Naur mysql-5.0.37/sql/log.cc mysql-5.0.37.fixed/sql/log.cc
--- mysql-5.0.37/sql/log.cc	2008-09-29 12:57:44.000000000 -0700
+++ mysql-5.0.37.fixed/sql/log.cc	2008-09-29 13:00:42.000000000 -0700
@@ -379,6 +379,7 @@
   index_file_name[0] = 0;
   bzero((char*) &log_file,sizeof(log_file));
   bzero((char*) &index_file, sizeof(index_file));
+  bzero((char*) &purge_temp, sizeof(purge_temp));
 }
 
 /* this is called only once */
@@ -395,6 +396,8 @@
     (void) pthread_mutex_destroy(&LOCK_log);
     (void) pthread_mutex_destroy(&LOCK_index);
     (void) pthread_cond_destroy(&update_cond);
+    if (my_b_inited(&purge_temp))
+      close_cached_file(&purge_temp);
   }
   DBUG_VOID_RETURN;
 }
@@ -1158,8 +1161,38 @@
 
   if (need_mutex)
     pthread_mutex_lock(&LOCK_index);
+
+  /* Check that requested file exists in index. */
   if ((error=find_log_pos(&log_info, to_log, 0 /*no mutex*/)))
+  {
+    sql_print_error("MYSQL_LOG::purge_logs was called with file %s not "
+                    "listed in the index.", to_log);
     goto err;
+  }
+
+  /*
+    For crash recovery reasons the index needs to be updated before
+    any files are deleted. Move files to be deleted into a temp file
+    to be processed after the index is updated.
+  */
+  if (!my_b_inited(&purge_temp))
+  {
+    if (error=open_cached_file(&purge_temp, mysql_tmpdir, TEMP_PREFIX,
+                               DISK_BUFFER_SIZE, MYF(MY_WME)))
+    {
+      sql_print_error("MYSQL_LOG::purge_logs failed to open purge_temp");
+      goto err;
+    }
+  }
+  else
+  {
+    if (error=reinit_io_cache(&purge_temp, WRITE_CACHE, 0, 0, 1))
+    {
+      sql_print_error("MYSQL_LOG::purge_logs failed to reinit purge_temp "
+                      "for write");
+      goto err;
+    }
+  }
 
   /*
     File name exists in index file; delete until we find this file
@@ -1170,12 +1203,65 @@
   while ((strcmp(to_log,log_info.log_file_name) || (exit_loop=included)) &&
          !log_in_use(log_info.log_file_name))
   {
+    if ((error=my_b_write(&purge_temp, (byte*)log_info.log_file_name,
+                          strlen(log_info.log_file_name))) ||
+        (error=my_b_write(&purge_temp, (byte*)"\n", 1)))
+    {
+      sql_print_error("MYSQL_LOG::purge_logs failed to copy %s to purge_temp",
+                      log_info.log_file_name);
+      goto err;
+    }
+
+    if (find_next_log(&log_info, 0) || exit_loop)
+      break;
+ }
+
+  /* We know how many files to delete. Update index file. */
+  if (error=update_log_index(&log_info, need_update_threads))
+  {
+    sql_print_error("MSYQL_LOG::purge_logs failed to update the index file");
+    goto err;
+  }
+
+  DBUG_EXECUTE_IF("crash_after_update_index", abort(););
+
+  /* Switch purge_temp for read. */
+  if (error=reinit_io_cache(&purge_temp, READ_CACHE, 0, 0, 0))
+  {
+    sql_print_error("MSYQL_LOG::purge_logs failed to reinit purge_temp "
+                    "for read");
+    goto err;
+  }
+
+  /* Read each entry from purge_temp and delete the file. */
+  for (;;)
+  {
     ulong file_size= 0;
+    uint length;
+
+    if ((length=my_b_gets(&purge_temp, log_info.log_file_name,
+                          FN_REFLEN)) <= 1)
+    {
+      if (purge_temp.error)
+      {
+        error= purge_temp.error;
+        sql_print_error("MSYQL_LOG::purge_logs error %d reading from "
+                        "purge_temp", error);
+        goto err;
+      }
+
+      /* Reached EOF */
+      break;
+    }
+
+    /* Get rid of the trailing '\n' */
+    log_info.log_file_name[length-1]= 0;
+
     if (decrease_log_space) //stat the file we want to delete
     {
       MY_STAT s;
 
-      /* 
+      /*
          If we could not stat, we can't know the amount
          of space that deletion will free. In most cases,
          deletion won't work either, so it's not a problem.
@@ -1191,18 +1277,20 @@
       if we could delete it, take its size into account
     */
     DBUG_PRINT("info",("purging %s",log_info.log_file_name));
-    if (!my_delete(log_info.log_file_name, MYF(0)) && decrease_log_space)
+    if (my_delete(log_info.log_file_name, MYF(0)))
+    {
+      /*
+        The downside of failing to delete a file is the lost disk space.
+        It won't cause any functional problems because find_uniq_filename
+        ensures that a given log name isn't reused.
+      */
+      sql_print_error("MYSQL_LOG::purge_logs failed to delete %s",
+                      log_info.log_file_name);
+    }
+    else if (decrease_log_space)
       *decrease_log_space-= file_size;
-    if (find_next_log(&log_info, 0) || exit_loop)
-      break;
   }
 
-  /*
-    If we get killed -9 here, the sysadmin would have to edit
-    the log index file after restart - otherwise, this should be safe
-  */
-  error= update_log_index(&log_info, need_update_threads);
-
 err:
   if (need_mutex)
     pthread_mutex_unlock(&LOCK_index);
diff -Naur mysql-5.0.37/sql/sql_class.h mysql-5.0.37.fixed/sql/sql_class.h
--- mysql-5.0.37/sql/sql_class.h	2008-09-29 12:57:44.000000000 -0700
+++ mysql-5.0.37.fixed/sql/sql_class.h	2008-09-29 13:00:42.000000000 -0700
@@ -198,6 +198,13 @@
   time_t last_time,query_start;
   IO_CACHE log_file;
   IO_CACHE index_file;
+  /*
+    purge_temp is a temp file used in purge_logs so that the index file
+    can be updated before deleting files from disk, yielding better crash
+    recovery. It is created on demand the first time purge_logs is called
+    and then reused for subsequent calls. It is cleaned up in cleanup().
+  */
+  IO_CACHE purge_temp;
   char *name;
   char time_buff[20],db[NAME_LEN+1];
   char log_file_name[FN_REFLEN],index_file_name[FN_REFLEN];