bcachefs: Always increment bucket gen on bucket reuse

Not doing so confuses copygc
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/alloc_background.c

@@ -860,12 +860,22 @@ static int bch2_invalidate_one_bucket2(struct btree_trans *trans,
 	g = bucket(ca, b);
 	m = READ_ONCE(g->mark);
 
-	bch2_mark_alloc_bucket(c, ca, b, true, gc_pos_alloc(c, NULL), 0);
+	invalidating_cached_data = m.cached_sectors != 0;
+
+	/*
+	 * If we're not invalidating cached data, we only increment the bucket
+	 * gen in memory here, the incremented gen will be updated in the btree
+	 * by bch2_trans_mark_pointer():
+	 */
+
+	if (!invalidating_cached_data)
+		bch2_invalidate_bucket(c, ca, b, &m);
+	else
+		bch2_mark_alloc_bucket(c, ca, b, true, gc_pos_alloc(c, NULL), 0);
 
 	spin_unlock(&c->freelist_lock);
 	percpu_up_read(&c->mark_lock);
 
-	invalidating_cached_data = m.cached_sectors != 0;
 	if (!invalidating_cached_data)
 		goto out;
 
@@ -887,18 +897,26 @@ static int bch2_invalidate_one_bucket2(struct btree_trans *trans,
 	if (ret)
 		return ret;
 
-	/*
-	 * The allocator has to start before journal replay is finished - thus,
-	 * we have to trust the in memory bucket @m, not the version in the
-	 * btree:
-	 */
 	percpu_down_read(&c->mark_lock);
-	g = bucket(ca, b);
+	g = bucket(ca, iter->pos.offset);
 	m = READ_ONCE(g->mark);
-	u = alloc_mem_to_key(g, m);
+
+	if (unlikely(!test_bit(BCH_FS_ALLOC_WRITTEN, &c->flags))) {
+		/*
+		 * During journal replay, and if gc repairs alloc info at
+		 * runtime, the alloc info in the btree might not be up to date
+		 * yet - so, trust the in memory mark:
+		 */
+		u		= alloc_mem_to_key(g, m);
+	} else {
+		u		= bch2_alloc_unpack(k);
+		u.read_time	= g->io_time[READ];
+		u.write_time	= g->io_time[WRITE];
+	}
+
 	percpu_up_read(&c->mark_lock);
 
-	invalidating_cached_data = m.cached_sectors != 0;
+	invalidating_cached_data = u.cached_sectors != 0;
 
 	u.gen++;
 	u.data_type	= 0;

fs/bcachefs/buckets.c

@@ -1496,6 +1496,8 @@ static int bch2_trans_mark_pointer(struct btree_trans *trans,
 	struct bkey_s_c k_a;
 	struct bkey_alloc_unpacked u;
 	struct bkey_i_alloc *a;
+	struct bucket *g;
+	struct bucket_mark m;
 	int ret;
 
 	ret = trans_get_key(trans, BTREE_ID_ALLOC,
@@ -1504,26 +1506,32 @@ static int bch2_trans_mark_pointer(struct btree_trans *trans,
 	if (ret < 0)
 		return ret;
 
-	if (k_a.k->type != KEY_TYPE_alloc ||
-	    (!ret && unlikely(!test_bit(BCH_FS_ALLOC_WRITTEN, &c->flags)))) {
+	percpu_down_read(&c->mark_lock);
+	g = bucket(ca, iter->pos.offset);
+	m = READ_ONCE(g->mark);
+
+	if (unlikely(!test_bit(BCH_FS_ALLOC_WRITTEN, &c->flags) && !ret)) {
 		/*
 		 * During journal replay, and if gc repairs alloc info at
 		 * runtime, the alloc info in the btree might not be up to date
 		 * yet - so, trust the in memory mark - unless we're already
 		 * updating that key:
 		 */
-		struct bucket *g;
-		struct bucket_mark m;
-
-		percpu_down_read(&c->mark_lock);
-		g	= bucket(ca, iter->pos.offset);
-		m	= READ_ONCE(g->mark);
-		u	= alloc_mem_to_key(g, m);
-		percpu_up_read(&c->mark_lock);
+		u		= alloc_mem_to_key(g, m);
 	} else {
-		u = bch2_alloc_unpack(k_a);
+		u		= bch2_alloc_unpack(k_a);
+		u.read_time	= g->io_time[READ];
+		u.write_time	= g->io_time[WRITE];
 	}
 
+	percpu_up_read(&c->mark_lock);
+
+	/*
+	 * Incrementing the bucket gen can be done lazily:
+	 */
+	if (gen_after(m.gen, u.gen) && !u.data_type)
+		u.gen = m.gen;
+
 	ret = __mark_pointer(c, k, p, sectors, data_type, u.gen, &u.data_type,
 			     &u.dirty_sectors, &u.cached_sectors);
 	if (ret)