f2fs_gc returns -EINVAL via f2fs_balance_fs when there is enough free
secs after write checkpoint, but with gc_merge enabled, it will cause
the sleep time of gc thread to be set to no_gc_sleep_time even if there
are many dirty segments can be selected.

Signed-off-by: qixiaoyu1 <qixiaoyu1@xiaomi.com>
---
 fs/f2fs/gc.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index d5fb426e0747..e2f8a2dae908 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -150,8 +150,11 @@ static int gc_thread_func(void *data)
 		gc_control.nr_free_secs = foreground ? 1 : 0;
 
 		/* if return value is not zero, no victim was selected */
-		if (f2fs_gc(sbi, &gc_control))
-			wait_ms = gc_th->no_gc_sleep_time;
+		if (f2fs_gc(sbi, &gc_control)) {
+			/* don't bother wait_ms by foreground gc */
+			if (!foreground)
+				wait_ms = gc_th->no_gc_sleep_time;
+		}
 
 		if (foreground)
 			wake_up_all(&gc_th->fggc_wq);
-- 
2.36.1