bcachefs: Shutdown path improvements

We're seeing occasional firings of the assertion in the key cache
shutdown code that nr_dirty == 0, which means we must sometimes be doing
transaction commits after we've gone read only.

Cleanups & changes:
 - BCH_FS_ALLOC_CLEAN renamed to BCH_FS_CLEAN_SHUTDOWN
 - new helper bch2_btree_interior_updates_flush(), which returns true if
   it had to wait
 - bch2_btree_flush_writes() now also returns true if there were btree
   writes in flight
 - __bch2_fs_read_only now checks if btree writes were in flight in the
   shutdown loop: btree write completion does a transaction update, to
   update the pointer in the parent node
 - assert that !BCH_FS_CLEAN_SHUTDOWN in __bch2_trans_commit

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/fs/bcachefs/migrate.c b/fs/bcachefs/migrate.c
index 6defc33322b3..5345697f2712 100644
--- a/fs/bcachefs/migrate.c
+++ b/fs/bcachefs/migrate.c
@@ -175,10 +175,7 @@ next:
 			goto err;
 	}
 
-	/* flush relevant btree updates */
-	closure_wait_event(&c->btree_interior_update_wait,
-			   !bch2_btree_interior_updates_nr_pending(c));
-
+	bch2_btree_interior_updates_flush(c);
 	ret = 0;
 err:
 	bch2_trans_exit(&trans);