Merge lp:~vlad-lesin/percona-server/5.1-bug801989 into lp:percona-server/5.1

[Vlad Lesin]

Bug #801989 fix.

[Alexey Kopytov (akopytov)]

Vlad,

The patch looks good. But as we discussed it should be recommitted to a GCA 5.1 branch.

Since you have to recommit it anyway, please add braces around the statement in the if() block, as done in everywhere in InnoDB.

review: Needs Fixing

Unmerged revisions

482. By Vlad Lesin on 2012-09-13

The bug #801989 fix.

The main idea of this fix is to return "true" on success and "false" otherwise
from os_file_set_nocache(). That allows to process O_DIRECT flag setting failures.

If setting O_DIRECT failes on log files the srv_unix_file_flush_method is set
to SRV_UNIX_O_DIRECT value to do fsync() on log files. If O_DIRECT fails on
other files the error is ignored to do buffered I/O on filesystems that do not
support direct I/O(for example tmpfs).

=== modified file 'Percona-Server/storage/innodb_plugin/include/os0file.h'
--- Percona-Server/storage/innodb_plugin/include/os0file.h	2012-06-14 09:16:03 +0000
+++ Percona-Server/storage/innodb_plugin/include/os0file.h	2012-09-13 07:30:44 +0000
@@ -338,9 +338,10 @@
 				used by a backup program reading the file */
 	ibool*		success);/*!< out: TRUE if succeed, FALSE if error */
 /****************************************************************//**
-Tries to disable OS caching on an opened file descriptor. */
+Tries to disable OS caching on an opened file descriptor.
+@return TRUE if operation is success and FALSE otherwise */
 UNIV_INTERN
-void
+ibool
 os_file_set_nocache(
 /*================*/
 	int		fd,		/*!< in: file descriptor to alter */

=== modified file 'Percona-Server/storage/innodb_plugin/os/os0file.c'
--- Percona-Server/storage/innodb_plugin/os/os0file.c	2012-06-14 09:16:03 +0000
+++ Percona-Server/storage/innodb_plugin/os/os0file.c	2012-09-13 07:30:44 +0000
@@ -1218,9 +1218,10 @@
 }
 
 /****************************************************************//**
-Tries to disable OS caching on an opened file descriptor. */
+Tries to disable OS caching on an opened file descriptor.
+@return TRUE if operation is success and FALSE otherwise */
 UNIV_INTERN
-void
+ibool
 os_file_set_nocache(
 /*================*/
 	int		fd		/*!< in: file descriptor to alter */
@@ -1241,6 +1242,7 @@
 			"  InnoDB: Failed to set DIRECTIO_ON "
 			"on file %s: %s: %s, continuing anyway\n",
 			file_name, operation_name, strerror(errno_save));
+		return FALSE;
 	}
 #elif defined(O_DIRECT)
 	if (fcntl(fd, F_SETFL, O_DIRECT) == -1) {
@@ -1258,8 +1260,10 @@
 				"'Invalid argument' on Linux on tmpfs, "
 				"see MySQL Bug#26662\n");
 		}
+		return FALSE;
 	}
 #endif
+	return TRUE;
 }
 
 /****************************************************************//**
@@ -1488,7 +1492,10 @@
 
 	/* ALL_O_DIRECT: O_DIRECT also for transaction log file */
 	if (srv_unix_file_flush_method == SRV_UNIX_ALL_O_DIRECT) {
-		os_file_set_nocache(file, name, mode_str);
+		/* Do fsync() on log files when setting O_DIRECT fails.
+		See log_io_complete() */
+		if (!os_file_set_nocache(file, name, mode_str))
+			srv_unix_file_flush_method = SRV_UNIX_O_DIRECT;
 	}
 
 #ifdef USE_FILE_LOCK