From 507345929617876f306b20eb541c9126945fba2c Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher <jakobunt@gmail.com>
Date: Wed, 29 Jul 2020 20:29:24 +0200
Subject: [PATCH] Revert "getdents_c: read from two threads"

This made the code more complicated without reproducing
the problem.

This reverts commit 77632b7554000f2e832a0e9fded1a3894b2502c3.
---
 contrib/getdents-debug/getdents_c/Makefile   |  2 +-
 contrib/getdents-debug/getdents_c/getdents.c | 65 +++++---------------
 2 files changed, 17 insertions(+), 50 deletions(-)

diff --git a/contrib/getdents-debug/getdents_c/Makefile b/contrib/getdents-debug/getdents_c/Makefile
index 1a9d4d2..95e47dc 100644
--- a/contrib/getdents-debug/getdents_c/Makefile
+++ b/contrib/getdents-debug/getdents_c/Makefile
@@ -1,2 +1,2 @@
 getdents_c: *.c Makefile
-	gcc getdents.c -lpthread -o getdents_c
+	gcc getdents.c -o getdents_c
diff --git a/contrib/getdents-debug/getdents_c/getdents.c b/contrib/getdents-debug/getdents_c/getdents.c
index d504976..936bd0b 100644
--- a/contrib/getdents-debug/getdents_c/getdents.c
+++ b/contrib/getdents-debug/getdents_c/getdents.c
@@ -1,7 +1,6 @@
 // See ../getdents/getdents.go for some info on why
 // this exists.
 
-#define _GNU_SOURCE
 #include <fcntl.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -10,38 +9,6 @@
 #include <sys/stat.h>
 #include <sys/syscall.h>
 #include <errno.h>
-#include <pthread.h>
-
-static pthread_mutex_t mutex;
-static int sum;
-
-struct up {
-    pthread_mutex_t *my_mutex;
-    pthread_mutex_t *other_mutex;
-    int fd;
-};
-
-void *reader(void *arg) {
-    struct up* up = (struct up*)arg;
-    int fd = up->fd;
-    char tmp[10000];
-    while(1) {
-        pthread_mutex_lock(up->my_mutex);
-        int n = syscall(SYS_getdents64, fd, tmp, sizeof(tmp));
-        if (n > 0) {
-            printf("t%ld: n=%d\n", gettid(), n);
-        } else {
-            printf("t%ld: n=0 errno=%d total %d bytes\n", gettid(), errno, sum);
-            if (n < 0) {
-                exit(1);
-            }
-            pthread_mutex_unlock(up->other_mutex);
-            break;
-        }
-        sum += n;
-        pthread_mutex_unlock(up->other_mutex);
-    }
-}
 
 int main(int argc, char *argv[])
 {
@@ -54,28 +21,28 @@ int main(int argc, char *argv[])
     const char *path = argv[1];
 
     for (int i = 1 ; ; i ++ ) {
-        sum = 0;
         int fd = open(path, O_RDONLY);
         if (fd == -1) {
             perror("open");
             exit(1);
         }
-        pthread_t reader1_thread, reader2_thread;
-        pthread_mutex_t m1 = PTHREAD_MUTEX_INITIALIZER, m2 = PTHREAD_MUTEX_INITIALIZER;
-        pthread_mutex_lock(&m2);
-        struct up up1, up2;
-        up1.fd = fd;
-        up1.my_mutex = &m1;
-        up1.other_mutex = &m2;
-        up2.fd = fd;
-        up2.my_mutex = &m2;
-        up2.other_mutex = &m1;
-        pthread_create(&reader1_thread, NULL, reader, &up1);
-        pthread_create(&reader2_thread, NULL, reader, &up2);
-        pthread_join(reader1_thread, NULL);
-        pthread_join(reader2_thread, NULL);
+
+        char tmp[10000];
+        int sum = 0;
+        printf("%3d: getdents64: ", i);
+        for ( ; ; ) {
+            int n = syscall(SYS_getdents64, fd, tmp, sizeof(tmp));
+            printf("n=%d; ", n);
+            if (n <= 0) {
+                printf("errno=%d total %d bytes\n", errno, sum);
+                if (n < 0) {
+                    exit(1);
+                }
+                break;
+            }
+            sum += n;
+        }
         close(fd);
-        printf("---\n");
         usleep(100000);
     }
 }