Commit 1f8aede7 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: fix bch2_journal_keys_peek_prev_min() underflow 



Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent f5109c20

fs/bcachefs/btree_journal_iter.c

+15 −5
Original line number Diff line number Diff line
@@ -137,12 +137,15 @@ struct bkey_i *bch2_journal_keys_peek_prev_min(struct bch_fs *c, enum btree_id b 
	struct journal_key *k;



	BUG_ON(*idx > keys->nr);



	if (!keys->nr)

		return NULL;

search:

	if (!*idx)

		*idx = __bch2_journal_key_search(keys, btree_id, level, pos);



	while (*idx < keys->nr &&

	       __journal_key_cmp(btree_id, level, end_pos, idx_to_key(keys, *idx - 1)) >= 0) {

	       __journal_key_cmp(btree_id, level, end_pos, idx_to_key(keys, *idx)) >= 0) {

		(*idx)++;

		iters++;

		if (iters == 10) {
@@ -151,18 +154,23 @@ struct bkey_i *bch2_journal_keys_peek_prev_min(struct bch_fs *c, enum btree_id b 
		}

	}



	if (*idx == keys->nr)

		--(*idx);



	struct bkey_i *ret = NULL;

	rcu_read_lock(); /* for overwritten_ranges */



	while ((k = *idx < keys->nr ? idx_to_key(keys, *idx) : NULL)) {

	while (true) {

		k = idx_to_key(keys, *idx);

		if (__journal_key_cmp(btree_id, level, end_pos, k) > 0)

			break;



		if (k->overwritten) {

			if (k->overwritten_range)

				*idx = rcu_dereference(k->overwritten_range)->start - 1;

			else

				*idx -= 1;

				*idx = rcu_dereference(k->overwritten_range)->start;

			if (!*idx)

				break;

			--(*idx);

			continue;

		}
@@ -171,6 +179,8 @@ struct bkey_i *bch2_journal_keys_peek_prev_min(struct bch_fs *c, enum btree_id b 
			break;

		}



		if (!*idx)

			break;

		--(*idx);

		iters++;

		if (iters == 10) {