#include "btree_locking.h"
#include "btree_types.h"
-struct lock_class_key bch2_btree_node_lock_key;
+static struct lock_class_key bch2_btree_node_lock_key;
+
+void bch2_btree_lock_init(struct btree_bkey_cached_common *b)
+{
+ __six_lock_init(&b->lock, "b->c.lock", &bch2_btree_node_lock_key);
+}
+
+#ifdef CONFIG_LOCKDEP
+void bch2_assert_btree_nodes_not_locked(void)
+{
+ BUG_ON(lock_class_is_held(&bch2_btree_node_lock_key));
+}
+#endif
/* Btree node locking: */
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);
prt_printf(&buf, "backtrace:");
prt_newline(&buf);
printbuf_indent_add(&buf, 2);
- bch2_prt_backtrace(&buf, trans->locking_wait.task);
+ bch2_prt_task_backtrace(&buf, trans->locking_wait.task);
printbuf_indent_sub(&buf, 2);
prt_newline(&buf);
}
while (g->nr)
lock_graph_up(g);
+
+ if (cycle)
+ return 0;
+
trace_and_count(trans->c, trans_restart_would_deadlock_recursion_limit, trans, _RET_IP_);
return btree_trans_restart(orig_trans, BCH_ERR_transaction_restart_deadlock_recursion_limit);
}
int ret;
if (trans->lock_must_abort) {
+ if (cycle)
+ return -1;
+
trace_and_count(trans->c, trans_restart_would_deadlock, trans, _RET_IP_);
return btree_trans_restart(trans, BCH_ERR_transaction_restart_would_deadlock);
}
b = &READ_ONCE(path->l[top->level].b)->c;
if (IS_ERR_OR_NULL(b)) {
- BUG_ON(!lock_graph_remove_non_waiters(&g));
+ /*
+ * 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;
}
* locked:
*/
six_lock_readers_add(&b->lock, -readers);
- ret = __btree_node_lock_nopath(trans, b, SIX_LOCK_write, lock_may_not_fail);
+ ret = __btree_node_lock_nopath(trans, b, SIX_LOCK_write,
+ lock_may_not_fail, _RET_IP_);
six_lock_readers_add(&b->lock, readers);
if (ret)
return ret;
}
+void bch2_btree_node_lock_write_nofail(struct btree_trans *trans,
+ struct btree_path *path,
+ struct btree_bkey_cached_common *b)
+{
+ struct btree_path *linked;
+ unsigned i;
+ int ret;
+
+ /*
+ * XXX BIG FAT NOTICE
+ *
+ * Drop all read locks before taking a write lock:
+ *
+ * This is a hack, because bch2_btree_node_lock_write_nofail() is a
+ * hack - but by dropping read locks first, this should never fail, and
+ * we only use this in code paths where whatever read locks we've
+ * already taken are no longer needed:
+ */
+
+ trans_for_each_path(trans, linked) {
+ if (!linked->nodes_locked)
+ continue;
+
+ for (i = 0; i < BTREE_MAX_DEPTH; i++)
+ if (btree_node_read_locked(linked, i)) {
+ btree_node_unlock(trans, linked, i);
+ btree_path_set_dirty(linked, BTREE_ITER_NEED_RELOCK);
+ }
+ }
+
+ ret = __btree_node_lock_write(trans, path, b, true);
+ BUG_ON(ret);
+}
+
/* relock */
static inline bool btree_path_get_locks(struct btree_trans *trans,
return true;
}
fail:
- if (trace)
+ if (trace && !trans->notrace_relock_fail)
trace_and_count(trans->c, btree_path_relock_fail, trans, _RET_IP_, path, level);
return false;
}
return btree_path_get_locks(trans, path, false);
}
+int __bch2_btree_path_relock(struct btree_trans *trans,
+ struct btree_path *path, unsigned long trace_ip)
+{
+ if (!bch2_btree_path_relock_norestart(trans, path, trace_ip)) {
+ trace_and_count(trans->c, trans_restart_relock_path, trans, trace_ip, path);
+ return btree_trans_restart(trans, BCH_ERR_transaction_restart_relock_path);
+ }
+
+ return 0;
+}
+
__flatten
bool bch2_btree_path_upgrade_norestart(struct btree_trans *trans,
struct btree_path *path, unsigned long trace_ip)
return 0;
}
+int bch2_trans_relock_notrace(struct btree_trans *trans)
+{
+ struct btree_path *path;
+
+ if (unlikely(trans->restarted))
+ return -((int) trans->restarted);
+
+ trans_for_each_path(trans, path)
+ if (path->should_be_locked &&
+ !bch2_btree_path_relock_norestart(trans, path, _RET_IP_)) {
+ return btree_trans_restart(trans, BCH_ERR_transaction_restart_relock);
+ }
+ return 0;
+}
+
void bch2_trans_unlock(struct btree_trans *trans)
{
struct btree_path *path;
* bch2_gc_btree_init_recurse() doesn't use btree iterators for walking
* btree nodes, it implements its own walking:
*/
- EBUG_ON(!trans->is_initial_gc &&
- lock_class_is_held(&bch2_btree_node_lock_key));
+ if (!trans->is_initial_gc)
+ bch2_assert_btree_nodes_not_locked();
}
bool bch2_trans_locked(struct btree_trans *trans)
return false;
}
+int __bch2_trans_mutex_lock(struct btree_trans *trans,
+ struct mutex *lock)
+{
+ int ret;
+
+ bch2_trans_unlock(trans);
+ mutex_lock(lock);
+ ret = bch2_trans_relock(trans);
+ if (ret)
+ mutex_unlock(lock);
+ return ret;
+}
+
/* Debug */
#ifdef CONFIG_BCACHEFS_DEBUG
projects / bcachefs-tools-debian / blobdiff