bcachefs: Fix incorrectly freeing btree_path in alloc path

Clearing path->preserve means the path will be dropping in
bch2_trans_begin() - but on transaction restart, we're likely to need
that path again.

This fixes a livelock in the allocation path.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This commit is contained in:
Kent Overstreet 2022-08-05 17:08:35 -04:00 • committed by Kent Overstreet
commit 17047fbced