Sergey Bugaev, le sam. 01 mai 2021 19:56:31 +0300, a ecrit: > On Sat, May 1, 2021 at 7:38 PM Samuel Thibault <samuel.thiba...@gnu.org> > wrote: > > > on the other hand, the tar format, with its 512-byte > > > blocks, sounds very much like a filesystem image to me. isofs uses > > > diskfs, why doesn't tarfs? > > > > It's not exactly the same since you have compression in the way. But > > yes, that looks similar enough. > > Does tar actually do any compression?
Tar itself, no. > And in case of tarfs, the compression is handled by the store > abstraction, which makes it transparent to the rest of the logic. Ah, ok. And in the zip case? > > Diskfs' pager_read_page does *not* have to lock the node, it just reads > > and returns the data. That's again a point where you see that having > > also the cache is in the way rather than helping. > > Hmm, but doesn't the page reading/writing implementation need to > access the file size, atime/mtime, etc.? All of which may be changed > concurrently. IIRC it isn't handled by the pager itself. Samuel
