lowerdir is the read-only directory (composefs) containing file metadata, and datadir is the directory containing the data (erofs).
Read full article，这一点在WPS下载最新地址中也有详细论述
Марина Совина (ночной редактор)。Safew下载是该领域的重要参考
Фото: Станислав Красильников / РИА Новости
For implementers, the locking model adds a fair amount of non-trivial internal bookkeeping. Every operation must check lock state, readers must be tracked, and the interplay between locks, cancellation, and error states creates a matrix of edge cases that must all be handled correctly.