1 files changed, 22 insertions, 4 deletions

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index a2ca483f9855..5c48825fd12d 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -31,19 +31,24 @@ static int gc_thread_func(void *data)
 	struct f2fs_sb_info *sbi = data;
 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
+	wait_queue_head_t *fggc_wq = &sbi->gc_thread->fggc_wq;
 	unsigned int wait_ms;
 
 	wait_ms = gc_th->min_sleep_time;
 
 	set_freezable();
 	do {
-		bool sync_mode;
+		bool sync_mode, foreground = false;
 
 		wait_event_interruptible_timeout(*wq,
 				kthread_should_stop() || freezing(current) ||
+				waitqueue_active(fggc_wq) ||
 				gc_th->gc_wake,
 				msecs_to_jiffies(wait_ms));
 
+		if (test_opt(sbi, GC_MERGE) && waitqueue_active(fggc_wq))
+			foreground = true;
+
 		/* give it a try one time */
 		if (gc_th->gc_wake)
 			gc_th->gc_wake = 0;
@@ -90,7 +95,10 @@ static int gc_thread_func(void *data)
 			goto do_gc;
 		}
 
-		if (!down_write_trylock(&sbi->gc_lock)) {
+		if (foreground) {
+			down_write(&sbi->gc_lock);
+			goto do_gc;
+		} else if (!down_write_trylock(&sbi->gc_lock)) {
 			stat_other_skip_bggc_count(sbi);
 			goto next;
 		}
@@ -107,14 +115,22 @@ static int gc_thread_func(void *data)
 		else
 			increase_sleep_time(gc_th, &wait_ms);
 do_gc:
-		stat_inc_bggc_count(sbi->stat_info);
+		if (!foreground)
+			stat_inc_bggc_count(sbi->stat_info);
 
 		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
 
+		/* foreground GC was been triggered via f2fs_balance_fs() */
+		if (foreground)
+			sync_mode = false;
+
 		/* if return value is not zero, no victim was selected */
-		if (f2fs_gc(sbi, sync_mode, true, false, NULL_SEGNO))
+		if (f2fs_gc(sbi, sync_mode, !foreground, false, NULL_SEGNO))
 			wait_ms = gc_th->no_gc_sleep_time;
 
+		if (foreground)
+			wake_up_all(&gc_th->fggc_wq);
+
 		trace_f2fs_background_gc(sbi->sb, wait_ms,
 				prefree_segments(sbi), free_segments(sbi));
 
@@ -148,6 +164,7 @@ int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
 
 	sbi->gc_thread = gc_th;
 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
+	init_waitqueue_head(&sbi->gc_thread->fggc_wq);
 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 	if (IS_ERR(gc_th->f2fs_gc_task)) {
@@ -165,6 +182,7 @@ void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
 	if (!gc_th)
 		return;
 	kthread_stop(gc_th->f2fs_gc_task);
+	wake_up_all(&gc_th->fggc_wq);
 	kfree(gc_th);
 	sbi->gc_thread = NULL;
 }