bcachefs: Fix order of gc_done passes

gc_stripes_done() and gc_reflink_done() may do alloc btree updates (i.e.
when deleting an indirect extent) - we need bucket gens to be fixed by
then.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_gc.c

@@ -1818,10 +1818,10 @@ int bch2_gc(struct bch_fs *c, bool initial, bool metadata_only)
 	if (!ret) {
 		bch2_journal_block(&c->journal);
 
-		ret   = bch2_gc_stripes_done(c, metadata_only) ?:
-			bch2_gc_reflink_done(c, metadata_only) ?:
-			bch2_gc_alloc_done(c, metadata_only) ?:
-			bch2_gc_done(c, initial, metadata_only);
+		ret   = bch2_gc_alloc_done(c, metadata_only) ?:
+			bch2_gc_done(c, initial, metadata_only) ?:
+			bch2_gc_stripes_done(c, metadata_only) ?:
+			bch2_gc_reflink_done(c, metadata_only);
 
 		bch2_journal_unblock(&c->journal);
 	}