bcachefs: Fix repair path for missing indirect extents

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

fs/bcachefs/reflink.c

@@ -185,8 +185,7 @@ static s64 gc_trigger_reflink_p_segment(struct btree_trans *trans,
 		} else {
 			bkey_error_init(update);
 			update->k.p		= p.k->p;
-			update->k.p.offset	= next_idx;
-			update->k.size		= next_idx - *idx;
+			update->k.size		= p.k->size;
 			set_bkey_val_u64s(&update->k, 0);
 		}