bcachefs: Improve invalidate_one_bucket() error messages

Make sure to check for lru entries that point to buckets that don't
exist as well as buckets in the wrong state, and improve the error
message we print out.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 35 insertions, 16 deletions

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index e8412fb1547e..83c750e049dc 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -1751,37 +1751,38 @@ void bch2_do_discards(struct bch_fs *c)
 
 static int invalidate_one_bucket(struct btree_trans *trans,
 				 struct btree_iter *lru_iter,
-				 struct bpos bucket,
+				 struct bkey_s_c lru_k,
 				 s64 *nr_to_invalidate)
 {
 	struct bch_fs *c = trans->c;
 	struct btree_iter alloc_iter = { NULL };
-	struct bkey_i_alloc_v4 *a;
+	struct bkey_i_alloc_v4 *a = NULL;
 	struct printbuf buf = PRINTBUF;
+	struct bpos bucket = u64_to_bucket(lru_k.k->p.offset);
 	unsigned cached_sectors;
 	int ret = 0;
 
 	if (*nr_to_invalidate <= 0)
 		return 1;
 
+	if (!bch2_dev_bucket_exists(c, bucket)) {
+		prt_str(&buf, "lru entry points to invalid bucket");
+		goto err;
+	}
+
 	a = bch2_trans_start_alloc_update(trans, &alloc_iter, bucket);
 	ret = PTR_ERR_OR_ZERO(a);
 	if (ret)
 		goto out;
 
 	if (lru_pos_time(lru_iter->pos) != alloc_lru_idx(a->v)) {
-		prt_printf(&buf, "alloc key does not point back to lru entry when invalidating bucket:\n  ");
-		bch2_bpos_to_text(&buf, lru_iter->pos);
-		prt_printf(&buf, "\n  ");
-		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&a->k_i));
-
-		bch_err(c, "%s", buf.buf);
-		if (test_bit(BCH_FS_CHECK_LRUS_DONE, &c->flags)) {
-			bch2_inconsistent_error(c);
-			ret = -EINVAL;
-		}
+		prt_str(&buf, "alloc key does not point back to lru entry when invalidating bucket:");
+		goto err;
+	}
 
-		goto out;
+	if (a->v.data_type != BCH_DATA_cached) {
+		prt_str(&buf, "lru entry points to non cached bucket:");
+		goto err;
 	}
 
 	if (!a->v.cached_sectors)
@@ -1810,6 +1811,26 @@ out:
 	bch2_trans_iter_exit(trans, &alloc_iter);
 	printbuf_exit(&buf);
 	return ret;
+err:
+	prt_str(&buf, "\n  lru key: ");
+	bch2_bkey_val_to_text(&buf, c, lru_k);
+
+	prt_str(&buf, "\n  lru entry: ");
+	bch2_lru_pos_to_text(&buf, lru_iter->pos);
+
+	prt_str(&buf, "\n  alloc key: ");
+	if (!a)
+		bch2_bpos_to_text(&buf, bucket);
+	else
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&a->k_i));
+
+	bch_err(c, "%s", buf.buf);
+	if (test_bit(BCH_FS_CHECK_LRUS_DONE, &c->flags)) {
+		bch2_inconsistent_error(c);
+		ret = -EINVAL;
+	}
+
+	goto out;
 }
 
 static void bch2_do_invalidates_work(struct work_struct *work)
@@ -1832,9 +1853,7 @@ static void bch2_do_invalidates_work(struct work_struct *work)
 				lru_pos(ca->dev_idx, 0, 0),
 				lru_pos(ca->dev_idx, U64_MAX, LRU_TIME_MAX),
 				BTREE_ITER_INTENT, k,
-			invalidate_one_bucket(&trans, &iter,
-					      u64_to_bucket(k.k->p.offset),
-					      &nr_to_invalidate));
+			invalidate_one_bucket(&trans, &iter, k, &nr_to_invalidate));
 
 		if (ret < 0) {
 			percpu_ref_put(&ca->ref);