fix with Freund's suggestion

Author: kelvich

src/backend/storage/file/copydir.c

@@ -192,7 +192,7 @@ copy_file(char *fromfile, char *tofile)
 		 * cache and hopefully get the kernel to start writing them out before
 		 * the fsync comes.
 		 */
-		pg_flush_data(dstfd, offset, nbytes, false);
+		pg_flush_data(dstfd, offset, nbytes);
 	}
 
 	if (CloseTransientFile(dstfd))

src/backend/storage/file/fd.c

@@ -395,10 +395,8 @@ pg_fdatasync(int fd)
  * flushed.
  */
 void
-pg_flush_data(int fd, off_t offset, off_t nbytes, bool isdir)
+pg_flush_data(int fd, off_t offset, off_t nbytes)
 {
-	(void) isdir;  	/* this can be unused on some archs */
-
 	/*
 	 * Right now file flushing is primarily used to avoid making later
 	 * fsync()/fdatasync() calls have a less impact. Thus don't trigger
@@ -454,10 +452,6 @@ pg_flush_data(int fd, off_t offset, off_t nbytes, bool isdir)
 		 * (msync()), and then remove the mapping again (munmap()).
 		 */
 
-		/* mmap() will not work with dirs */
-		if (isdir)
-			return;
-
 		/* mmap() need exact length when we want to map whole file */
 		if ((offset == 0) && (nbytes == 0))
 		{
@@ -472,7 +466,7 @@ pg_flush_data(int fd, off_t offset, off_t nbytes, bool isdir)
 			/* aling to pagesize with underestimation */
 			nbytes = (nbytes/pagesize)*pagesize;
 
-			if(nbytes == 0)
+			if (nbytes == 0)
 				return;
 		}
 
@@ -1539,7 +1533,7 @@ FileWriteback(File file, off_t offset, int amount)
 	if (returnCode < 0)
 		return;
 
-	pg_flush_data(VfdCache[file].fd, offset, amount, false);
+	pg_flush_data(VfdCache[file].fd, offset, amount);
 }
 
 int
@@ -2945,7 +2939,8 @@ pre_sync_fname(const char *fname, bool isdir, int elevel)
 	 * pg_flush_data() ignores errors, which is ok because this is only a
 	 * hint.
 	 */
-	pg_flush_data(fd, 0, 0, isdir);
+	if (!isdir)
+		pg_flush_data(fd, 0, 0);
 
 	(void) CloseTransientFile(fd);
 }

src/include/storage/fd.h

@@ -116,7 +116,7 @@ extern int	pg_fsync(int fd);
 extern int	pg_fsync_no_writethrough(int fd);
 extern int	pg_fsync_writethrough(int fd);
 extern int	pg_fdatasync(int fd);
-extern void pg_flush_data(int fd, off_t offset, off_t amount, bool isdir);
+extern void pg_flush_data(int fd, off_t offset, off_t amount);
 extern void fsync_fname(const char *fname, bool isdir);
 extern int	durable_rename(const char *oldfile, const char *newfile, int loglevel);
 extern int	durable_link_or_rename(const char *oldfile, const char *newfile, int loglevel);