+/*
+ * We've already checked that generation numbers in the bucket_gens btree are
+ * valid for buckets that exist; this just checks for keys for nonexistent
+ * buckets.
+ */
+static noinline_for_stack
+int bch2_check_bucket_gens_key(struct btree_trans *trans,
+ struct btree_iter *iter,
+ struct bkey_s_c k)
+{
+ struct bch_fs *c = trans->c;
+ struct bkey_i_bucket_gens g;
+ struct bch_dev *ca;
+ u64 start = bucket_gens_pos_to_alloc(k.k->p, 0).offset;
+ u64 end = bucket_gens_pos_to_alloc(bpos_nosnap_successor(k.k->p), 0).offset;
+ u64 b;
+ bool need_update = false, dev_exists;
+ struct printbuf buf = PRINTBUF;
+ int ret = 0;
+
+ BUG_ON(k.k->type != KEY_TYPE_bucket_gens);
+ bkey_reassemble(&g.k_i, k);
+
+ /* if no bch_dev, skip out whether we repair or not */
+ dev_exists = bch2_dev_exists2(c, k.k->p.inode);
+ if (!dev_exists) {
+ if (fsck_err_on(!dev_exists, c,
+ "bucket_gens key for invalid device:\n %s",
+ (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
+ ret = bch2_btree_delete_at(trans, iter, 0);
+ }
+ goto out;
+ }
+
+ ca = bch_dev_bkey_exists(c, k.k->p.inode);
+ if (fsck_err_on(end <= ca->mi.first_bucket ||
+ start >= ca->mi.nbuckets, c,
+ "bucket_gens key for invalid buckets:\n %s",
+ (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
+ ret = bch2_btree_delete_at(trans, iter, 0);
+ goto out;
+ }
+
+ for (b = start; b < ca->mi.first_bucket; b++)
+ if (fsck_err_on(g.v.gens[b & KEY_TYPE_BUCKET_GENS_MASK], c,
+ "bucket_gens key has nonzero gen for invalid bucket")) {
+ g.v.gens[b & KEY_TYPE_BUCKET_GENS_MASK] = 0;
+ need_update = true;
+ }
+
+ for (b = ca->mi.nbuckets; b < end; b++)
+ if (fsck_err_on(g.v.gens[b & KEY_TYPE_BUCKET_GENS_MASK], c,
+ "bucket_gens key has nonzero gen for invalid bucket")) {
+ g.v.gens[b & KEY_TYPE_BUCKET_GENS_MASK] = 0;
+ need_update = true;