VSW_INSTALLED
vfssw[fstype].vsw_flag |= VSW_INSTALLED;
if ((vfssw[fstype].vsw_flag & VSW_INSTALLED) == 0) {
vfssw[fstype].vsw_flag &= ~VSW_INSTALLED;
vfssw[fstype].vsw_flag |= VSW_INSTALLED;
if ((vfssw[fstype].vsw_flag & VSW_INSTALLED) == 0) {
vfssw[fstype].vsw_flag &= ~VSW_INSTALLED;
#define VFS_INSTALLED(vfsswp) (((vfsswp)->vsw_flag & VSW_INSTALLED) != 0)