bzr commit into mysql-6.0-falcon-team branch (vvaintroub:2860) Bug#39212

[Vladislav Vaintroub]

#At file:///media/disk/bzr/mysql-6.0-falcon-team/

 2860 Vladislav Vaintroub	2008-10-09
      Bug#39212 Falcon exception on recovery when one of the log files 
      is empty
      
      Reason is a bug with reiserfs file system - read of a file of 
      size 1 to 4095 returns error (EINVAL), if file is opened with 
      O_DIRECT. ext3 behaves correct and returns number of bytes read.
      
      Solved with workaround: initial size of serial log files is now  
      at least 4096 bytes.
modified:
  storage/falcon/SerialLogFile.cpp

=== modified file 'storage/falcon/SerialLogFile.cpp'
--- a/storage/falcon/SerialLogFile.cpp	2008-09-12 17:01:24 +0000
+++ b/storage/falcon/SerialLogFile.cpp	2008-10-09 11:27:17 +0000
@@ -362,8 +362,11 @@ int64 SerialLogFile::size(void)
 
 void SerialLogFile::zap()
 {
-	UCHAR *junk = new UCHAR[sectorSize * 2];
-	//UCHAR *buffer = (UCHAR*) (((UIPTR) junk + sectorSize - 1) / sectorSize * sectorSize);
+        // HACK: Files of size between 1 and 4095 bytes cannot be read on 
+        // linux on reiserfs file system, if file is opened  with O_DIRECT. 
+        // Hence initialSize below is 4K at least.
+        size_t initialSize = MAX(sectorSize, 4096); 
+	UCHAR *junk = new UCHAR[initialSize +sectorSize];
 	UCHAR *buffer = ALIGN(junk, sectorSize);
 	memset(buffer, 0, sectorSize);
 	write(0, sectorSize, (SerialLogBlock*) buffer);