SecurityDescriptorsBlockSize
ALIGN(sds_size - SecurityDescriptorsBlockSize, 16);
SecurityDescriptorsBlockSize);
next = sbi->security.next_off & (SecurityDescriptorsBlockSize - 1);
left = SecurityDescriptorsBlockSize - next;
sbi->security.next_off += SecurityDescriptorsBlockSize + left;
mirr_off = sbi->security.next_off + SecurityDescriptorsBlockSize;