bcachefs: Assert that we don't lock nodes when !trans->locked

We rely on the trans->locked to know if a trans has nodes locked for
assertions about deadlocks; there can't be more than one trans in the
same process that is locked.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/btree_locking.h b/fs/bcachefs/btree_locking.h
index dd0a2a1..7c07f9f 100644 (file)
--- a/fs/bcachefs/btree_locking.h
+++ b/fs/bcachefs/btree_locking.h
@@ -218,14 +218,12 @@ static inline int __btree_node_lock_nopath(struct btree_trans *trans,
                                         bool lock_may_not_fail,
                                         unsigned long ip)
 {
-       int ret;
-
        trans->lock_may_not_fail = lock_may_not_fail;
        trans->lock_must_abort  = false;
        trans->locking          = b;
 
-       ret = six_lock_ip_waiter(&b->lock, type, &trans->locking_wait,
-                                bch2_six_check_for_deadlock, trans, ip);
+       int ret = six_lock_ip_waiter(&b->lock, type, &trans->locking_wait,
+                                    bch2_six_check_for_deadlock, trans, ip);
        WRITE_ONCE(trans->locking, NULL);
        WRITE_ONCE(trans->locking_wait.start_time, 0);
 
@@ -284,6 +282,7 @@ static inline int btree_node_lock(struct btree_trans *trans,
        int ret = 0;
 
        EBUG_ON(level >= BTREE_MAX_DEPTH);
+       bch2_trans_verify_not_unlocked(trans);
 
        if (likely(six_trylock_type(&b->lock, type)) ||
            btree_node_lock_increment(trans, b, level, (enum btree_node_locked_type) type) ||

diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index 396d052..1433aef 100644 (file)
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -731,6 +731,18 @@ static void btree_update_nodes_written(struct btree_update *as)
        bch2_fs_fatal_err_on(ret && !bch2_journal_error(&c->journal), c,
                             "%s", bch2_err_str(ret));
 err:
+       /*
+        * Ensure transaction is unlocked before using btree_node_lock_nopath()
+        * (the use of which is always suspect, we need to work on removing this
+        * in the future)
+        *
+        * It should be, but bch2_path_get_unlocked_mut() -> bch2_path_get()
+        * calls bch2_path_upgrade(), before we call path_make_mut(), so we may
+        * rarely end up with a locked path besides the one we have here:
+        */
+       bch2_trans_unlock(trans);
+       bch2_trans_begin(trans);
+
        /*
         * We have to be careful because another thread might be getting ready
         * to free as->b and calling btree_update_reparent() on us - we'll
@@ -750,18 +762,6 @@ err:
                 * we're in journal error state:
                 */
 
-               /*
-                * Ensure transaction is unlocked before using
-                * btree_node_lock_nopath() (the use of which is always suspect,
-                * we need to work on removing this in the future)
-                *
-                * It should be, but bch2_path_get_unlocked_mut() -> bch2_path_get()
-                * calls bch2_path_upgrade(), before we call path_make_mut(), so
-                * we may rarely end up with a locked path besides the one we
-                * have here:
-                */
-               bch2_trans_unlock(trans);
-               bch2_trans_begin(trans);
                btree_path_idx_t path_idx = bch2_path_get_unlocked_mut(trans,
                                                as->btree_id, b->c.level, b->key.k.p);
                struct btree_path *path = trans->paths + path_idx;

diff --git a/fs/bcachefs/btree_update_interior.h b/fs/bcachefs/btree_update_interior.h
index 02c6eca..10f4009 100644 (file)
--- a/fs/bcachefs/btree_update_interior.h
+++ b/fs/bcachefs/btree_update_interior.h
@@ -159,6 +159,8 @@ static inline int bch2_foreground_maybe_merge(struct btree_trans *trans,
                                              unsigned level,
                                              unsigned flags)
 {
+       bch2_trans_verify_not_unlocked(trans);
+
        return  bch2_foreground_maybe_merge_sibling(trans, path, level, flags,
                                                    btree_prev_sib) ?:
                bch2_foreground_maybe_merge_sibling(trans, path, level, flags,