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fixup bcachefs: Deadlock cycle detector

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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet
2023-01-20 15:35:07 -05:00
parent 896f1b316f
commit 80df5b8cac
1 changed files with 26 additions and 2 deletions
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28
fs/bcachefs/btree_locking.c
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@@ -99,6 +99,12 @@ static void lock_graph_up(struct lock_graph *g)
closure_put(&g->g[--g->nr].trans->ref);
}
static noinline void lock_graph_pop_all(struct lock_graph *g)
{
while (g->nr)
lock_graph_up(g);
}
static void lock_graph_down(struct lock_graph *g, struct btree_trans *trans)
{
closure_get(&trans->ref);
@@ -274,8 +280,26 @@ int bch2_check_for_deadlock(struct btree_trans *trans, struct printbuf *cycle)
b = &READ_ONCE(path->l[top->level].b)->c;
if (unlikely(IS_ERR_OR_NULL(b))) {
BUG_ON(!lock_graph_remove_non_waiters(&g));
if (IS_ERR_OR_NULL(b)) {
/*
* If we get here, it means we raced with the
* other thread updating its btree_path
* structures - which means it can't be blocked
* waiting on a lock:
*/
if (!lock_graph_remove_non_waiters(&g)) {
/*
* If lock_graph_remove_non_waiters()
* didn't do anything, it must be
* because we're being called by debugfs
* checking for lock cycles, which
* invokes us on btree_transactions that
* aren't actually waiting on anything.
* Just bail out:
*/
lock_graph_pop_all(&g);
}
goto next;
}