Commit 30e615a2 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Fix gap buffer bug in bch2_journal_key_insert_take() 



Multiple bug fixes for journal iters:

 - When the journal keys gap buffer is resized, we have to adjust the
   iterators for moving the gap to the end
 - We don't want to rewind iterators to point to the key we just
   inserted if it's not for the correct btree/level

Also, add some new assertions.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 2d793e93

fs/bcachefs/btree_journal_iter.c

+45 −10
Original line number Diff line number Diff line
@@ -130,12 +130,30 @@ struct bkey_i *bch2_journal_keys_peek_slot(struct bch_fs *c, enum btree_id btree 
	return bch2_journal_keys_peek_upto(c, btree_id, level, pos, pos, &idx);

}



static void journal_iter_verify(struct journal_iter *iter)

{

	struct journal_keys *keys = iter->keys;

	size_t gap_size = keys->size - keys->nr;



	BUG_ON(iter->idx >= keys->gap &&

	       iter->idx <  keys->gap + gap_size);



	if (iter->idx < keys->size) {

		struct journal_key *k = keys->data + iter->idx;



		int cmp = cmp_int(k->btree_id,	iter->btree_id) ?:

			  cmp_int(k->level,	iter->level);

		BUG_ON(cmp < 0);

	}

}



static void journal_iters_fix(struct bch_fs *c)

{

	struct journal_keys *keys = &c->journal_keys;

	/* The key we just inserted is immediately before the gap: */

	size_t gap_end = keys->gap + (keys->size - keys->nr);

	struct btree_and_journal_iter *iter;

	struct journal_key *new_key = &keys->data[keys->gap - 1];

	struct journal_iter *iter;



	/*

	 * If an iterator points one after the key we just inserted, decrement
@@ -143,9 +161,14 @@ static void journal_iters_fix(struct bch_fs *c) 
	 * decrement was unnecessary, bch2_btree_and_journal_iter_peek() will

	 * handle that:

	 */

	list_for_each_entry(iter, &c->journal_iters, journal.list)

		if (iter->journal.idx == gap_end)

			iter->journal.idx = keys->gap - 1;

	list_for_each_entry(iter, &c->journal_iters, list) {

		journal_iter_verify(iter);

		if (iter->idx		== gap_end &&

		    new_key->btree_id	== iter->btree_id &&

		    new_key->level	== iter->level)

			iter->idx = keys->gap - 1;

		journal_iter_verify(iter);

	}

}



static void journal_iters_move_gap(struct bch_fs *c, size_t old_gap, size_t new_gap)
@@ -192,7 +215,12 @@ int bch2_journal_key_insert_take(struct bch_fs *c, enum btree_id id, 
	if (idx > keys->gap)

		idx -= keys->size - keys->nr;



	size_t old_gap = keys->gap;



	if (keys->nr == keys->size) {

		journal_iters_move_gap(c, old_gap, keys->size);

		old_gap = keys->size;



		struct journal_keys new_keys = {

			.nr			= keys->nr,

			.size			= max_t(size_t, keys->size, 8) * 2,
@@ -216,7 +244,7 @@ int bch2_journal_key_insert_take(struct bch_fs *c, enum btree_id id, 
		keys->gap	= keys->nr;

	}



	journal_iters_move_gap(c, keys->gap, idx);

	journal_iters_move_gap(c, old_gap, idx);



	move_gap(keys, idx);
@@ -301,16 +329,21 @@ static void bch2_journal_iter_advance(struct journal_iter *iter) 


static struct bkey_s_c bch2_journal_iter_peek(struct journal_iter *iter)

{

	journal_iter_verify(iter);



	while (iter->idx < iter->keys->size) {

		struct journal_key *k = iter->keys->data + iter->idx;



	while (k < iter->keys->data + iter->keys->size &&

	       k->btree_id	== iter->btree_id &&

	       k->level		== iter->level) {

		int cmp = cmp_int(k->btree_id,	iter->btree_id) ?:

			  cmp_int(k->level,	iter->level);

		if (cmp > 0)

			break;

		BUG_ON(cmp);



		if (!k->overwritten)

			return bkey_i_to_s_c(k->k);



		bch2_journal_iter_advance(iter);

		k = iter->keys->data + iter->idx;

	}



	return bkey_s_c_null;
@@ -330,6 +363,8 @@ static void bch2_journal_iter_init(struct bch_fs *c, 
	iter->level	= level;

	iter->keys	= &c->journal_keys;

	iter->idx	= bch2_journal_key_search(&c->journal_keys, id, level, pos);



	journal_iter_verify(iter);

}



static struct bkey_s_c bch2_journal_iter_peek_btree(struct btree_and_journal_iter *iter)