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, 9 insertions, 5 deletions

diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index f847928ab743..33c54803e0a2 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -2099,29 +2099,33 @@ void bch2_btree_node_write(struct bch_fs *c, struct btree *b,
 	}
 }
 
-static void __bch2_btree_flush_all(struct bch_fs *c, unsigned flag)
+static bool __bch2_btree_flush_all(struct bch_fs *c, unsigned flag)
 {
 	struct bucket_table *tbl;
 	struct rhash_head *pos;
 	struct btree *b;
 	unsigned i;
+	bool ret = false;
 restart:
 	rcu_read_lock();
 	for_each_cached_btree(b, c, tbl, i, pos)
 		if (test_bit(flag, &b->flags)) {
 			rcu_read_unlock();
 			wait_on_bit_io(&b->flags, flag, TASK_UNINTERRUPTIBLE);
+			ret = true;
 			goto restart;
 		}
 	rcu_read_unlock();
+
+	return ret;
 }
 
-void bch2_btree_flush_all_reads(struct bch_fs *c)
+bool bch2_btree_flush_all_reads(struct bch_fs *c)
 {
-	__bch2_btree_flush_all(c, BTREE_NODE_read_in_flight);
+	return __bch2_btree_flush_all(c, BTREE_NODE_read_in_flight);
 }
 
-void bch2_btree_flush_all_writes(struct bch_fs *c)
+bool bch2_btree_flush_all_writes(struct bch_fs *c)
 {
-	__bch2_btree_flush_all(c, BTREE_NODE_write_in_flight);
+	return __bch2_btree_flush_all(c, BTREE_NODE_write_in_flight);
 }