bcachefs: Kill read lock dropping in bch2_btree_node_lock_write_nofail()

dropping read locks in bch2_btree_node_lock_write_nofail() dates from
before we had the cycle detector; we can now tell the cycle detector
directly when taking a lock may not fail because we can't handle
transaction restarts.

This is needed for adding should_be_locked asserts.

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

diff --git a/fs/bcachefs/btree_locking.c b/fs/bcachefs/btree_locking.c
index b9b151e693ed60ecc3dc9147cc34902643cfc7aa..f2caf491957efc2345c082323516e58fe2a35302 100644 (file)
--- a/fs/bcachefs/btree_locking.c
+++ b/fs/bcachefs/btree_locking.c
@@ -440,33 +440,7 @@ 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, iter;
-       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, iter) {
-               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);
+       int ret = __btree_node_lock_write(trans, path, b, true);
        BUG_ON(ret);
 }