bcachefs: Don't call bch2_btree_interior_update_will_free_node() until after update succeeds

Originally, btree splits always succeeded once we got to the point of
recursing to the btree_insert_node() call.

But that changed when we switched to not taking intent locks all the way
up to the root, and that introduced a bug, because
bch2_btree_interior_update_will_free_node() cancels paending writes and
reparents a node that's going to be made visible on disk by another
btree update to the current btree update.

This was discovered in recent backpointers work, because
bch2_btree_interior_update_will_free_node() also clears the
will_make_reachable flag, causing backpointer target lookup to
spuriously thing it had found a dangling backpointer (when the
backpointer just hadn't been created yet by
btree_update_nodes_written()).

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

0 files changed, 0 insertions, 0 deletions