bk commit into 6.0 tree (vlad:1.2813) BUG#33484

[vvaintroub]

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ChangeSet@stripped, 2008-02-12 15:00:10-05:00, vlad@stripped +1 -0
  Bug#33484 - 
  Cannot create Falcon table due to error in pwrite() on Linux 2.4 on 
  NFS file system. The problem was file system specific 
  alignment/buffersize requirement when using O_DIRECT on Linux 2.4 (
  on NFS it is 32KB), incompatible with Falcon buffer sizes.
  
  Solution: do not use O_DIRECT on Linux < 2.6, since it is too 
  complicated. If somebody want performance , he would need 2.6 
  anyway.

  storage/falcon/IO.cpp@stripped, 2008-02-12 15:00:06-05:00, vlad@stripped +34 -6
    - Do not use O_DIRECT on linux versions < 2.6
    - Correct inconsistent indentation

diff -Nrup a/storage/falcon/IO.cpp b/storage/falcon/IO.cpp
--- a/storage/falcon/IO.cpp	2008-01-31 14:25:43 -05:00
+++ b/storage/falcon/IO.cpp	2008-02-12 15:00:06 -05:00
@@ -43,13 +43,18 @@
 #include "config.h"
 #endif
 
-#ifdef TARGET_OS_LINUX
+#ifdef  __linux__
 #include <linux/unistd.h>
+#include <sys/utsname.h>
+static  int getLinuxVersion();
+#define KERNEL_VERSION(a, b, c)	((a)<<16 | (b)<<8 | (c))
+#define haveBrokenODirect()	(getLinuxVersion() < KERNEL_VERSION(2,6,0))
 #else
-#define   LOCK_SH   1	/* shared lock */
-#define   LOCK_EX   2	/* exclusive lock */
-#define   LOCK_NB   4	/* don't block when locking */
-#define   LOCK_UN   8	/* unlock */
+#define LOCK_SH   1	/* shared lock */
+#define LOCK_EX   2	/* exclusive lock */
+#define LOCK_NB   4	/* don't block when locking */
+#define LOCK_UN   8	/* unlock */
+#define haveBrokenODirect()	0
 #endif
 #include <sys/file.h>
 #define O_BINARY		0
@@ -57,6 +62,7 @@
 #define MKDIR(dir)			mkdir(dir, S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR | S_IWGRP | S_IXUSR | S_IXGRP)
 #endif
 
+
 #ifndef O_SYNC
 #define O_SYNC		0
 #endif
@@ -630,7 +636,7 @@ void IO::reportWrites(void)
 int IO::getWriteMode(int attempt)
 {
 #ifdef O_DIRECT
-	if (attempt == 0 && falcon_direct_io > 0)
+	if (attempt == 0 && falcon_direct_io > 0 && !haveBrokenODirect())
 		return O_DIRECT;
 #endif
 
@@ -639,3 +645,25 @@ int IO::getWriteMode(int attempt)
 	
 	return 0;
 }
+
+#ifdef __linux__
+int getLinuxVersion()
+{
+	static int vers = -1;
+
+	if(vers != -1)
+		return vers;
+
+	struct utsname utsname;
+
+	if(uname(&utsname) == -1)
+		return vers = 0;
+
+	int major, minor ,release;
+
+	if (sscanf(utsname.release,"%d.%d.%d",&major, &minor,&release) != 3)
+		return vers = 0;
+
+	return vers = KERNEL_VERSION(major,minor,release);
+}
+#endif