From 8aaee94d463f781fbd5377b7d96234342de9c6eb Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Mon, 3 Oct 2022 16:41:17 -0400 Subject: [PATCH] bcachefs: Fix a deadlock in btree_update_nodes_written() btree_node_lock_nopath() is something we'd like to get rid of, it's always prone to deadlocks if we accidentally are holding other locks, because it doesn't mark the lock it's taking in a path: we'll want to get rid of it in the future, but for now this patch works it by calling bch2_trans_unlock(). Signed-off-by: Kent Overstreet --- fs/bcachefs/btree_update_interior.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c index fd44492150b05..247555dffa3f9 100644 --- a/fs/bcachefs/btree_update_interior.c +++ b/fs/bcachefs/btree_update_interior.c @@ -650,6 +650,17 @@ 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 get_unlocked_mut_path() -> 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); btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_intent); mark_btree_node_locked(&trans, path, b->c.level, SIX_LOCK_intent); path->l[b->c.level].lock_seq = b->c.lock.state.seq; -- 2.30.2