BTRFS_FS_CLOSING_START 2629 fs/btrfs/ctree.h if (test_bit(BTRFS_FS_CLOSING_START, &fs_info->flags)) { BTRFS_FS_CLOSING_START 3980 fs/btrfs/disk-io.c set_bit(BTRFS_FS_CLOSING_START, &fs_info->flags);