f2fs: make sure trace all f2fs_issue_flush

The root device's issue flush trace is missing,
add it and tracing the result from submit.

Fixes d50aaeec90 ("f2fs: show actual device info in tracepoints")
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -441,7 +441,8 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
 	}
 }
 
-static int __submit_flush_wait(struct block_device *bdev)
+static int __submit_flush_wait(struct f2fs_sb_info *sbi,
+				struct block_device *bdev)
 {
 	struct bio *bio = f2fs_bio_alloc(0);
 	int ret;
@@ -450,23 +451,24 @@ static int __submit_flush_wait(struct block_device *bdev)
 	bio->bi_bdev = bdev;
 	ret = submit_bio_wait(bio);
 	bio_put(bio);
+
+	trace_f2fs_issue_flush(bdev, test_opt(sbi, NOBARRIER),
+				test_opt(sbi, FLUSH_MERGE), ret);
 	return ret;
 }
 
 static int submit_flush_wait(struct f2fs_sb_info *sbi)
 {
-	int ret = __submit_flush_wait(sbi->sb->s_bdev);
+	int ret = __submit_flush_wait(sbi, sbi->sb->s_bdev);
 	int i;
 
-	if (sbi->s_ndevs && !ret) {
-		for (i = 1; i < sbi->s_ndevs; i++) {
-			trace_f2fs_issue_flush(FDEV(i).bdev,
-					test_opt(sbi, NOBARRIER),
-					test_opt(sbi, FLUSH_MERGE));
-			ret = __submit_flush_wait(FDEV(i).bdev);
-			if (ret)
-				break;
-		}
+	if (!sbi->s_ndevs || ret)
+		return ret;
+
+	for (i = 1; i < sbi->s_ndevs; i++) {
+		ret = __submit_flush_wait(sbi, FDEV(i).bdev);
+		if (ret)
+			break;
 	}
 	return ret;
 }

include/trace/events/f2fs.h

@@ -1176,26 +1176,29 @@ TRACE_EVENT(f2fs_issue_reset_zone,
 TRACE_EVENT(f2fs_issue_flush,
 
 	TP_PROTO(struct block_device *dev, unsigned int nobarrier,
-					unsigned int flush_merge),
+				unsigned int flush_merge, int ret),
 
-	TP_ARGS(dev, nobarrier, flush_merge),
+	TP_ARGS(dev, nobarrier, flush_merge, ret),
 
 	TP_STRUCT__entry(
 		__field(dev_t,	dev)
 		__field(unsigned int, nobarrier)
 		__field(unsigned int, flush_merge)
+		__field(int,  ret)
 	),
 
 	TP_fast_assign(
 		__entry->dev	= dev->bd_dev;
 		__entry->nobarrier = nobarrier;
 		__entry->flush_merge = flush_merge;
+		__entry->ret = ret;
 	),
 
-	TP_printk("dev = (%d,%d), %s %s",
+	TP_printk("dev = (%d,%d), %s %s, ret = %d",
 		show_dev(__entry->dev),
 		__entry->nobarrier ? "skip (nobarrier)" : "issue",
-		__entry->flush_merge ? " with flush_merge" : "")
+		__entry->flush_merge ? " with flush_merge" : "",
+		__entry->ret)
 );
 
 TRACE_EVENT(f2fs_lookup_extent_tree_start,