bcachefs: Ensure buckets have io_time[READ] set

It's an error if a bucket is in state BCH_DATA_cached but not on the LRU
btree - i.e io_time[READ] == 0 - so, make sure it's set before adding
it.

Also, make some of the LRU code a bit clearer and more direct.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/alloc_background.c

@@ -583,6 +583,11 @@ int bch2_trans_mark_alloc(struct btree_trans *trans,
 			return ret;
 	}
 
+	if (new_a->data_type == BCH_DATA_cached &&
+	    !new_a->io_time[READ])
+		new_a->io_time[READ] = max_t(u64, 1, atomic64_read(&c->io_clock[READ].now));
+
+
 	old_lru = alloc_lru_idx(old_a);
 	new_lru = alloc_lru_idx(*new_a);
 
@@ -592,7 +597,7 @@ int bch2_trans_mark_alloc(struct btree_trans *trans,
 		if (ret)
 			return ret;
 
-		if (new_lru && new_a->io_time[READ] != new_lru)
+		if (new_a->data_type == BCH_DATA_cached)
 			new_a->io_time[READ] = new_lru;
 	}
 
@@ -869,10 +874,10 @@ static int bch2_check_alloc_to_lru_ref(struct btree_trans *trans,
 		if (!a.io_time[READ])
 			a.io_time[READ] = atomic64_read(&c->io_clock[READ].now);
 
-		ret = bch2_lru_change(trans,
+		ret = bch2_lru_set(trans,
 				   alloc_k.k->p.inode,
 				   alloc_k.k->p.offset,
-				      0, &a.io_time[READ]);
+				   &a.io_time[READ]);
 		if (ret)
 			goto err;
 

fs/bcachefs/btree_gc.c

@@ -1405,6 +1405,13 @@ static int bch2_alloc_write_key(struct btree_trans *trans,
 
 	a->v = new;
 
+	/*
+	 * The trigger normally makes sure this is set, but we're not running
+	 * triggers:
+	 */
+	if (a->v.data_type == BCH_DATA_cached && !a->v.io_time[READ])
+		a->v.io_time[READ] = max_t(u64, 1, atomic64_read(&c->io_clock[READ].now));
+
 	ret = bch2_trans_update(trans, iter, &a->k_i, BTREE_TRIGGER_NORUN);
 fsck_err:
 	return ret;

fs/bcachefs/lru.c

@@ -30,7 +30,7 @@ void bch2_lru_to_text(struct printbuf *out, struct bch_fs *c,
 	pr_buf(out, "idx %llu", le64_to_cpu(lru->idx));
 }
 
-static int lru_delete(struct btree_trans *trans, u64 id, u64 idx, u64 time)
+int bch2_lru_delete(struct btree_trans *trans, u64 id, u64 idx, u64 time)
 {
 	struct btree_iter iter;
 	struct bkey_s_c k;
@@ -72,7 +72,7 @@ static int lru_delete(struct btree_trans *trans, u64 id, u64 idx, u64 time)
 	return ret;
 }
 
-static int lru_set(struct btree_trans *trans, u64 lru_id, u64 idx, u64 *time)
+int bch2_lru_set(struct btree_trans *trans, u64 lru_id, u64 idx, u64 *time)
 {
 	struct btree_iter iter;
 	struct bkey_s_c k;
@@ -119,8 +119,8 @@ int bch2_lru_change(struct btree_trans *trans, u64 id, u64 idx,
 	if (old_time == *new_time)
 		return 0;
 
-	return  lru_delete(trans, id, idx, old_time) ?:
-		lru_set(trans, id, idx, new_time);
+	return  bch2_lru_delete(trans, id, idx, old_time) ?:
+		bch2_lru_set(trans, id, idx, new_time);
 }
 
 static int bch2_check_lru_key(struct btree_trans *trans,

fs/bcachefs/lru.h

@@ -10,6 +10,8 @@ void bch2_lru_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
 	.val_to_text	= bch2_lru_to_text,	\
 }
 
+int bch2_lru_delete(struct btree_trans *, u64, u64, u64);
+int bch2_lru_set(struct btree_trans *, u64, u64, u64 *);
 int bch2_lru_change(struct btree_trans *, u64, u64, u64, u64 *);
 
 int bch2_check_lrus(struct bch_fs *, bool);