[PATCH] xfs_io: add command line option -M to run as multi threaded process

[Amir Goldstein <amir73il@gmail.com>]

xfs_io -M will start by spawning an idle thread.
The purpose of this idle thread is to test io from a multi threaded
process. With single threaded process, the file table is not shared
and file structs are not reference counted.

So in order to detect file struct reference leaks, spawning an idle
thread will do the trick.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 io/Makefile |  2 +-
 io/init.c   | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/io/Makefile b/io/Makefile
index 1997ca9..032a8c7 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -13,7 +13,7 @@ CFILES = init.c \
 	mmap.c open.c parent.c pread.c prealloc.c pwrite.c seek.c shutdown.c \
 	sync.c truncate.c reflink.c
 
-LLDLIBS = $(LIBXCMD) $(LIBHANDLE)
+LLDLIBS = $(LIBXCMD) $(LIBHANDLE) $(LIBPTHREAD)
 LTDEPENDENCIES = $(LIBXCMD) $(LIBHANDLE)
 LLDFLAGS = -static-libtool-libs
 
diff --git a/io/init.c b/io/init.c
index 6b88cc6..1d1b97f 100644
--- a/io/init.c
+++ b/io/init.c
@@ -16,6 +16,7 @@
  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#include <pthread.h>
 #include "platform_defs.h"
 #include "command.h"
 #include "input.h"
@@ -25,6 +26,7 @@
 char	*progname;
 int	exitcode;
 int	expert;
+int	multithreaded;
 size_t	pagesize;
 struct timeval stopwatch;
 
@@ -141,7 +143,7 @@ init(
 	pagesize = getpagesize();
 	gettimeofday(&stopwatch, NULL);
 
-	while ((c = getopt(argc, argv, "ac:dFfmp:nrRstTVx")) != EOF) {
+	while ((c = getopt(argc, argv, "ac:dFfmMp:nrRstTVx")) != EOF) {
 		switch (c) {
 		case 'a':
 			flags |= IO_APPEND;
@@ -166,6 +168,9 @@ init(
 				exit(1);
 			}
 			break;
+		case 'M':
+			multithreaded = 1;
+			break;
 		case 'n':
 			flags |= IO_NONBLOCK;
 			break;
@@ -213,12 +218,37 @@ init(
 	add_check_command(init_check_command);
 }
 
+/*
+ * The purpose of this idle thread is to test io from a multi threaded process.
+ * With single threaded process, the file table is not shared and file structs
+ * are not reference counted. So in order to detect file struct reference
+ * leaks, spawning an idle thread will do the trick.
+ */
+void *
+idle_loop(void *arg)
+{
+	for (;;) pause();
+}
+
+void
+start_idle_thread()
+{
+	pthread_t t;
+
+	if (pthread_create(&t, NULL, idle_loop, NULL)) {
+		fprintf(stderr, "Error creating idle thread\n");
+		exit(1);
+	}
+}
+
 int
 main(
 	int	argc,
 	char	**argv)
 {
 	init(argc, argv);
+	if (multithreaded)
+		start_idle_thread();
 	command_loop();
 	return exitcode;
 }
-- 
2.7.4