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>

diff --git a/fs/bcachefs/btree_iter.h b/fs/bcachefs/btree_iter.h
index 9a3287da9a120ab96823ee4d933248f10d6943ac..5ca92b6bb3977593123ef0a446098b156de65ff2 100644 (file)
--- a/fs/bcachefs/btree_iter.h
+++ b/fs/bcachefs/btree_iter.h
@@ -335,7 +335,8 @@ void bch2_trans_copy_iter(struct btree_iter *, struct btree_iter *);
 
 static inline void set_btree_iter_dontneed(struct btree_iter *iter)
 {
-       iter->path->preserve = false;
+       if (!iter->trans->restarted)
+               iter->path->preserve = false;
 }
 
 void *bch2_trans_kmalloc(struct btree_trans *, size_t);