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bcachefs: Fix bch2_btree_iter_next_node()

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We were modifying state, then return -EINTR, causing us to skip nodes -
ouch.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This commit is contained in:
Kent Overstreet
2021-10-24 16:55:17 -04:00
committed by Kent Overstreet
parent b0d1b70af8
commit 979735df98
1 changed files with 36 additions and 18 deletions
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54
fs/bcachefs/btree_iter.c
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@@ -1462,6 +1462,11 @@ static int btree_path_traverse_one(struct btree_trans *trans,
unsigned depth_want = path->level;
int ret = 0;
if (unlikely(trans->restarted)) {
ret = -EINTR;
goto out;
}
/*
* Ensure we obey path->should_be_locked: if it's set, we can't unlock
* and re-traverse the path without a transaction restart:
@@ -1935,30 +1940,41 @@ struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
struct btree_trans *trans = iter->trans;
struct btree_path *path = iter->path;
struct btree *b = NULL;
unsigned l;
int ret;
BUG_ON(trans->restarted);
EBUG_ON(iter->path->cached);
bch2_btree_iter_verify(iter);
/* already got to end? */
/* already at end? */
if (!btree_path_node(path, path->level))
goto out;
btree_node_unlock(path, path->level);
path->l[path->level].b = BTREE_ITER_NO_NODE_UP;
path->level++;
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
ret = bch2_btree_path_traverse(trans, path, iter->flags);
if (ret)
goto err;
return NULL;
/* got to end? */
b = btree_path_node(path, path->level);
if (!b)
goto out;
if (!btree_path_node(path, path->level + 1)) {
btree_node_unlock(path, path->level);
path->l[path->level].b = BTREE_ITER_NO_NODE_UP;
path->level++;
return NULL;
}
if (bpos_cmp(iter->pos, b->key.k.p) < 0) {
if (!bch2_btree_node_relock(trans, path, path->level + 1)) {
__bch2_btree_path_unlock(path);
path->l[path->level].b = BTREE_ITER_NO_NODE_GET_LOCKS;
path->l[path->level + 1].b = BTREE_ITER_NO_NODE_GET_LOCKS;
btree_trans_restart(trans);
ret = -EINTR;
goto err;
}
b = btree_path_node(path, path->level + 1);
if (!bpos_cmp(iter->pos, b->key.k.p)) {
btree_node_unlock(path, path->level);
path->l[path->level].b = BTREE_ITER_NO_NODE_UP;
path->level++;
} else {
/*
* Haven't gotten to the end of the parent node: go back down to
* the next child node
@@ -1967,10 +1983,12 @@ struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
btree_path_set_pos(trans, path, bpos_successor(iter->pos),
iter->flags & BTREE_ITER_INTENT);
/* Unlock to avoid screwing up our lock invariants: */
btree_node_unlock(path, path->level);
path->level = iter->min_depth;
for (l = path->level + 1; l < BTREE_MAX_DEPTH; l++)
if (btree_lock_want(path, l) == BTREE_NODE_UNLOCKED)
btree_node_unlock(path, l);
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
bch2_btree_iter_verify(iter);