btrfs: remove no longer used btrfs_transaction_in_commit()

The function btrfs_transaction_in_commit() is no longer used, its last
use was removed in commit 11aeb97b ("btrfs: don't arbitrarily slow
down delalloc if we're committing"), so just remove it.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/transaction.c

@@ -1957,19 +1957,6 @@ static void update_super_roots(struct btrfs_fs_info *fs_info)
 		super->uuid_tree_generation = root_item->generation;
 }
 
-int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
-{
-	struct btrfs_transaction *trans;
-	int ret = 0;
-
-	spin_lock(&info->trans_lock);
-	trans = info->running_transaction;
-	if (trans)
-		ret = (trans->state >= TRANS_STATE_COMMIT_START);
-	spin_unlock(&info->trans_lock);
-	return ret;
-}
-
 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
 {
 	struct btrfs_transaction *trans;

fs/btrfs/transaction.h

@@ -277,7 +277,6 @@ int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
 				struct extent_io_tree *dirty_pages, int mark);
 int btrfs_wait_tree_log_extents(struct btrfs_root *root, int mark);
 int btrfs_transaction_blocked(struct btrfs_fs_info *info);
-int btrfs_transaction_in_commit(struct btrfs_fs_info *info);
 void btrfs_put_transaction(struct btrfs_transaction *transaction);
 void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
 			    struct btrfs_root *root);