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bcachefs: Fix gap buffer bug in bch2_journal_key_insert_take()

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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: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-04-06 21:45:46 -04:00
parent 2d793e9315
commit 30e615a2ce
1 changed files with 45 additions and 10 deletions
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55
fs/bcachefs/btree_journal_iter.c
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@ -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)
{
struct journal_key *k = iter->keys->data + iter->idx;
journal_iter_verify(iter);
while (iter->idx < iter->keys->size) {
struct journal_key *k = iter->keys->data + iter->idx;
int cmp = cmp_int(k->btree_id, iter->btree_id) ?:
cmp_int(k->level, iter->level);
if (cmp > 0)
break;
BUG_ON(cmp);
while (k < iter->keys->data + iter->keys->size &&
k->btree_id == iter->btree_id &&
k->level == iter->level) {
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)