btrfs: run delayed iputs before committing the transaction for data

Before we were waiting on iputs after we committed the transaction, but
this doesn't really make much sense.  We want to reclaim any space we
may have in order to be more likely to commit the transaction, due to
pinned space being added by running the delayed iputs.  Fix this by
making delayed iputs run before committing the transaction.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/space-info.c

@@ -1022,8 +1022,8 @@ static const enum btrfs_flush_state evict_flush_states[] = {
 
 static const enum btrfs_flush_state data_flush_states[] = {
 	FLUSH_DELALLOC_WAIT,
-	COMMIT_TRANS,
 	RUN_DELAYED_IPUTS,
+	COMMIT_TRANS,
 };
 
 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,