last_backup      1844 fs/btrfs/disk-io.c 	int last_backup;
last_backup      1847 fs/btrfs/disk-io.c 	last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
last_backup      1854 fs/btrfs/disk-io.c 	root_backup = info->super_for_commit->super_roots + last_backup;
last_backup      1857 fs/btrfs/disk-io.c 		next_backup = last_backup;