btrfs-progs: add task-utils

Support for monitoring progress of running tasks, based on timerfd and
pthreads.

Signed-off-by: Silvio Fricke <silvio.fricke@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

task-utils.c

@@ -0,0 +1,136 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <pthread.h>
+#include <sys/timerfd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "task-utils.h"
+
+struct task_info *task_init(void *(*threadfn)(void *), int (*postfn)(void *),
+			    void *thread_private)
+{
+	struct task_info *info = calloc(1, sizeof(struct task_info));
+
+	if (!info)
+		return NULL;
+
+	info->private_data = thread_private;
+	info->threadfn = threadfn;
+	info->postfn = postfn;
+
+	return info;
+}
+
+int task_start(struct task_info *info)
+{
+	int ret;
+
+	if (!info)
+		return -1;
+
+	if (!info->threadfn)
+		return -1;
+
+	ret = pthread_create(&info->id, NULL, info->threadfn,
+			     info->private_data);
+
+	if (ret == 0)
+		pthread_detach(info->id);
+	else
+		info->id = -1;
+
+	return ret;
+}
+
+void task_stop(struct task_info *info)
+{
+	if (!info)
+		return;
+
+	if (info->periodic.timer_fd)
+		close(info->periodic.timer_fd);
+
+	if (info->id > 0)
+		pthread_cancel(info->id);
+
+	if (info->postfn)
+		info->postfn(info->private_data);
+}
+
+void task_deinit(struct task_info *info)
+{
+	if (!info)
+		return;
+
+	free(info);
+}
+
+int task_period_start(struct task_info *info, unsigned int period_ms)
+{
+	unsigned int ns;
+	unsigned int sec;
+	struct itimerspec itval;
+
+	if (!info)
+		return -1;
+
+	info->periodic.timer_fd = timerfd_create(CLOCK_MONOTONIC, 0);
+	if (info->periodic.timer_fd == -1)
+		return info->periodic.timer_fd;
+
+	info->periodic.wakeups_missed = 0;
+
+	sec = period_ms / 1000;
+	ns = (period_ms - (sec * 1000)) * 1000;
+	itval.it_interval.tv_sec = sec;
+	itval.it_interval.tv_nsec = ns;
+	itval.it_value.tv_sec = sec;
+	itval.it_value.tv_nsec = ns;
+
+	return timerfd_settime(info->periodic.timer_fd, 0, &itval, NULL);
+};
+
+void task_period_wait(struct task_info *info)
+{
+	unsigned long long missed;
+	int ret;
+
+	if (!info)
+		return;
+
+	ret = read(info->periodic.timer_fd, &missed, sizeof (missed));
+	if (ret == -1) {
+		perror("read timer");
+		return;
+	}
+
+	if (missed > 0)
+		info->periodic.wakeups_missed += (missed - 1);
+}
+
+void task_period_stop(struct task_info *info)
+{
+	if (!info)
+		return;
+
+	if (info->periodic.timer_fd) {
+		timerfd_settime(info->periodic.timer_fd, 0, NULL, NULL);
+		close(info->periodic.timer_fd);
+	}
+}

task-utils.h

@@ -0,0 +1,47 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __TASK_UTILS_H_
+#define __TASK_UTILS_H_
+
+#include <pthread.h>
+
+struct periodic_info {
+	int timer_fd;
+	unsigned long long wakeups_missed;
+};
+
+struct task_info {
+	struct periodic_info periodic;
+	pthread_t id;
+	void *private_data;
+	void *(*threadfn)(void *);
+	int (*postfn)(void *);
+};
+
+/* task life cycle */
+struct task_info *task_init(void *(*threadfn)(void *), int (*postfn)(void *),
+			    void *thread_private);
+int task_start(struct task_info *info);
+void task_stop(struct task_info *info);
+void task_deinit(struct task_info *info);
+
+/* periodic life cycle */
+int task_period_start(struct task_info *info, unsigned int period_ms);
+void task_period_wait(struct task_info *info);
+void task_period_stop(struct task_info *info);
+
+#endif