bcachefs: Fix bch2_check_discard_freespace_key()

We weren't correctly checking the freespace btree - it's an extents
btree, which means we need to iterate over each bucket in a freespace
extent.

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

1 files changed, 35 insertions, 12 deletions

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index f774a660a681..cbe026fbecbf 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -788,10 +788,12 @@ static int bch2_bucket_do_index(struct btree_trans *trans,
 	if (ca->mi.freespace_initialized &&
 	    test_bit(BCH_FS_CHECK_ALLOC_DONE, &c->flags) &&
 	    bch2_trans_inconsistent_on(old.k->type != old_type, trans,
-			"incorrect key when %s %s btree (got %s should be %s)\n"
+			"incorrect key when %s %s:%llu:%llu:0 (got %s should be %s)\n"
 			"  for %s",
 			set ? "setting" : "clearing",
 			bch2_btree_ids[btree],
+			iter.pos.inode,
+			iter.pos.offset,
 			bch2_bkey_types[old.k->type],
 			bch2_bkey_types[old_type],
 			(bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {
@@ -1278,8 +1280,8 @@ fsck_err:
 	return ret;
 }
 
-static int bch2_check_discard_freespace_key(struct btree_trans *trans,
-					    struct btree_iter *iter)
+static int __bch2_check_discard_freespace_key(struct btree_trans *trans,
+					      struct btree_iter *iter)
 {
 	struct bch_fs *c = trans->c;
 	struct btree_iter alloc_iter;
@@ -1313,23 +1315,46 @@ static int bch2_check_discard_freespace_key(struct btree_trans *trans,
 	if (fsck_err_on(a->data_type != state ||
 			(state == BCH_DATA_free &&
 			 genbits != alloc_freespace_genbits(*a)), c,
-			"%s\n  incorrectly set in %s index (free %u, genbits %llu should be %llu)",
+			"%s\n  incorrectly set at %s:%llu:%llu:0 (free %u, genbits %llu should be %llu)",
 			(bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf),
 			bch2_btree_ids[iter->btree_id],
+			iter->pos.inode,
+			iter->pos.offset,
 			a->data_type == state,
 			genbits >> 56, alloc_freespace_genbits(*a) >> 56))
 		goto delete;
 out:
 fsck_err:
+	set_btree_iter_dontneed(&alloc_iter);
 	bch2_trans_iter_exit(trans, &alloc_iter);
 	printbuf_exit(&buf);
 	return ret;
 delete:
-	ret = bch2_btree_delete_extent_at(trans, iter,
-			iter->btree_id == BTREE_ID_freespace ? 1 : 0, 0);
+	ret =   bch2_btree_delete_extent_at(trans, iter,
+			iter->btree_id == BTREE_ID_freespace ? 1 : 0, 0) ?:
+		bch2_trans_commit(trans, NULL, NULL,
+			BTREE_INSERT_NOFAIL|BTREE_INSERT_LAZY_RW);
 	goto out;
 }
 
+static int bch2_check_discard_freespace_key(struct btree_trans *trans,
+					    struct btree_iter *iter,
+					    struct bpos end)
+{
+	if (!btree_node_type_is_extents(iter->btree_id)) {
+		return __bch2_check_discard_freespace_key(trans, iter);
+	} else {
+		int ret;
+
+		while (!bkey_eq(iter->pos, end) &&
+		       !(ret = btree_trans_too_many_iters(trans) ?:
+			       __bch2_check_discard_freespace_key(trans, iter)))
+			bch2_btree_iter_set_pos(iter, bpos_nosnap_successor(iter->pos));
+
+		return ret;
+	}
+}
+
 /*
  * 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
@@ -1481,16 +1506,14 @@ bkey_err:
 	if (ret < 0)
 		goto err;
 
-	ret = for_each_btree_key_commit(&trans, iter,
+	ret = for_each_btree_key2(&trans, iter,
 			BTREE_ID_need_discard, POS_MIN,
 			BTREE_ITER_PREFETCH, k,
-			NULL, NULL, BTREE_INSERT_NOFAIL|BTREE_INSERT_LAZY_RW,
-		bch2_check_discard_freespace_key(&trans, &iter)) ?:
-	      for_each_btree_key_commit(&trans, iter,
+		bch2_check_discard_freespace_key(&trans, &iter, k.k->p)) ?:
+	      for_each_btree_key2(&trans, iter,
 			BTREE_ID_freespace, POS_MIN,
 			BTREE_ITER_PREFETCH, k,
-			NULL, NULL, BTREE_INSERT_NOFAIL|BTREE_INSERT_LAZY_RW,
-		bch2_check_discard_freespace_key(&trans, &iter)) ?:
+		bch2_check_discard_freespace_key(&trans, &iter, k.k->p)) ?:
 	      for_each_btree_key_commit(&trans, iter,
 			BTREE_ID_bucket_gens, POS_MIN,
 			BTREE_ITER_PREFETCH, k,