1 files changed, 73 insertions, 0 deletions
diff --git a/src/os_qnx/os_qnx_fsync.c b/src/os_qnx/os_qnx_fsync.c
new file mode 100644
index 00000000..827fa446
--- /dev/null
+++ b/src/os_qnx/os_qnx_fsync.c
@@ -0,0 +1,73 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1997, 2012 Oracle and/or its affiliates.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+
+/*
+ * QNX has special requirements on FSYNC: if the file is a shared memory
+ * object, we can not call fsync because it is not implemented, instead,
+ * we set the O_DSYNC flag to the file descriptor  and then do an empty
+ * write so that all data are synced. We only sync this way if the file
+ * is a shared memory object, other types of ordinary files are still synced
+ * using fsync, to be not only faster but also atomic.
+ * We don't just set the O_DSYNC flag on open, since it would force all writes
+ * to be sync'ed. And we remove the O_DSYNC if it is not originally set to
+ * the file descriptor before passed in to this function.
+ * This is slightly different to the VxWorks and hp code above, since QNX does
+ * supply a fsync call, it just has a unique requirement.
+ */
+int
+__qnx_fsync(fhp)
+	DB_FH *fhp;
+{
+	int ret;
+	int fd, unset, flags;
+
+	fd = fhp->fd;
+	unset = 1;
+	ret = flags = 0;
+	if (F_ISSET(fhp, DB_FH_REGION))
+	{
+		RETRY_CHK(fcntl(fd, F_GETFL), ret);
+		if (ret == -1)
+			goto err;
+		/*
+		 * if already has O_DSYNC flag, we can't remove it
+		 * after the empty write
+		 */
+		if (ret & O_DSYNC != 0)
+			unset = 0;
+		else {
+			ret |= O_DSYNC;
+			flags = ret;
+			RETRY_CHK(fcntl(fd, F_SETFL, flags), ret);
+			if (ret == -1)
+				goto err;
+		}
+		/* Do an empty write, to force a sync */
+		RETRY_CHK(write(fd, "", 0), ret);
+		if (ret == -1)
+			goto err;
+		/* remove the O_DSYNC flag if necessary */
+		if (unset) {
+			RETRY_CHK(fcntl(fd, F_GETFL), ret);
+			if (ret == -1)
+				goto err;
+			ret &= ~O_DSYNC;
+			flags = ret;
+			RETRY_CHK(fcntl(fd, F_SETFL, flags), ret);
+			if (ret == -1)
+				goto err;
+		}
+	} else
+		RETRY_CHK(fdatasync(fd), ret);
+
+err:	return (ret);
+}