bcache: Make btree coalescing triggerable from sysfs

5 files changed, 19 insertions, 25 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 7256c0ebc3b8..3f9294c17cda 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -699,7 +699,6 @@ struct cache_set {
 	 * it's not while a gc is in progress.
 	 */
 	struct rw_semaphore	gc_lock;
-	struct mutex		trigger_gc_lock;
 
 	/* IO PATH */
 	struct bio_set		bio_read;
diff --git a/drivers/md/bcache/btree_gc.c b/drivers/md/bcache/btree_gc.c
index 77b6c34b839b..4f4b8c14fefc 100644
--- a/drivers/md/bcache/btree_gc.c
+++ b/drivers/md/bcache/btree_gc.c
@@ -419,6 +419,13 @@ void bch_gc(struct cache_set *c)
 	up_write(&c->gc_lock);
 	trace_bcache_gc_end(c);
 	bch_time_stats_update(&c->btree_gc_time, start_time);
+
+	/*
+	 * Wake up allocator in case it was waiting for buckets
+	 * because of not being able to inc gens
+	 */
+	for_each_cache(ca, c, i)
+		bch_wake_allocator(ca);
 }
 
 /* Btree coalescing */
@@ -716,9 +723,9 @@ static int bch_coalesce_btree(struct cache_set *c, enum btree_id btree_id)
 /**
  * bch_coalesce - coalesce adjacent nodes with low occupancy
  */
-static void bch_coalesce(struct cache_set *c)
+void bch_coalesce(struct cache_set *c)
 {
-	u64 start_time = local_clock();
+	u64 start_time;
 	enum btree_id id;
 
 	if (btree_gc_coalesce_disabled(c))
@@ -727,7 +734,9 @@ static void bch_coalesce(struct cache_set *c)
 	if (test_bit(CACHE_SET_GC_FAILURE, &c->flags))
 		return;
 
+	down_read(&c->gc_lock);
 	trace_bcache_gc_coalesce_start(c);
+	start_time = local_clock();
 
 	for (id = 0; id < BTREE_ID_NR; id++) {
 		int ret = c->btree_roots[id].b
@@ -743,8 +752,8 @@ static void bch_coalesce(struct cache_set *c)
 	}
 
 	bch_time_stats_update(&c->btree_coalesce_time, start_time);
-
 	trace_bcache_gc_coalesce_end(c);
+	up_read(&c->gc_lock);
 }
 
 static int bch_gc_thread(void *arg)
@@ -753,8 +762,6 @@ static int bch_gc_thread(void *arg)
 	struct io_clock *clock = &c->io_clock[WRITE];
 	unsigned long last = atomic_long_read(&clock->now);
 	unsigned last_kick = atomic_read(&c->kick_gc);
-	struct cache *ca;
-	unsigned i;
 
 	set_freezable();
 
@@ -781,22 +788,8 @@ static int bch_gc_thread(void *arg)
 		last = atomic_long_read(&clock->now);
 		last_kick = atomic_read(&c->kick_gc);
 
-		/*
-		 * avoid racing with sysfs trigger_gc - gc gets confused if it
-		 * runs concurrently with coalescing
-		 */
-		mutex_lock(&c->trigger_gc_lock);
 		bch_gc(c);
-
-		/*
-		 * Wake up allocator in case it was waiting for buckets
-		 * because of not being able to inc gens
-		 */
-		for_each_cache(ca, c, i)
-			bch_wake_allocator(ca);
-
 		bch_coalesce(c);
-		mutex_unlock(&c->trigger_gc_lock);
 
 		debug_check_no_locks_held();
 	}
diff --git a/drivers/md/bcache/btree_gc.h b/drivers/md/bcache/btree_gc.h
index 99c6ccdef2b1..91d31c05c4b9 100644
--- a/drivers/md/bcache/btree_gc.h
+++ b/drivers/md/bcache/btree_gc.h
@@ -5,6 +5,7 @@
 
 enum bkey_type;
 
+void bch_coalesce(struct cache_set *);
 void bch_gc(struct cache_set *);
 void bch_gc_thread_stop(struct cache_set *);
 int bch_gc_thread_start(struct cache_set *);
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index ee383193726d..69b44f81495c 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1070,7 +1070,6 @@ static struct cache_set *bch_cache_set_alloc(struct cache_sb *sb,
 	mutex_init(&c->mi_lock);
 
 	init_rwsem(&c->gc_lock);
-	mutex_init(&c->trigger_gc_lock);
 
 #define BCH_TIME_STAT(name, frequency_units, duration_units)		\
 	spin_lock_init(&c->name##_time.lock);
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 8e7e97979fed..9f73b6bc329f 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -54,6 +54,7 @@ write_attribute(detach);
 write_attribute(unregister);
 write_attribute(stop);
 write_attribute(clear_stats);
+write_attribute(trigger_btree_coalesce);
 write_attribute(trigger_gc);
 write_attribute(prune_cache);
 write_attribute(blockdev_volume_create);
@@ -832,13 +833,13 @@ STORE(__bch_cache_set)
 			return r;
 	}
 
+	if (attr == &sysfs_trigger_btree_coalesce)
+		bch_coalesce(c);
+
 	/* Debugging: */
 
-	if (attr == &sysfs_trigger_gc) {
-		mutex_lock(&c->trigger_gc_lock);
+	if (attr == &sysfs_trigger_gc)
 		bch_gc(c);
-		mutex_unlock(&c->trigger_gc_lock);
-	}
 
 	if (attr == &sysfs_prune_cache) {
 		struct shrink_control sc;
@@ -942,6 +943,7 @@ static struct attribute *bch_cache_set_internal_files[] = {
 	&sysfs_writeback_keys_done,
 	&sysfs_writeback_keys_failed,
 
+	&sysfs_trigger_btree_coalesce,
 	&sysfs_trigger_gc,
 	&sysfs_prune_cache,
 	&sysfs_foreground_write_ratelimit_enabled,