Messages in this thread | | | Date | Thu, 26 Aug 2004 09:35:38 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: silent semantic changes with reiser4 |
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On Thu, 26 Aug 2004, Christoph Hellwig wrote: > > > Are you saying that with reiser4, you can open a device or fifo with > > O_DIRECTORY? > > That's what I thought, but as far as I can follow the code this is not > actually true.
It should be possible to do, though. There's nothing really different in making the "default" (unnamed) fork be a special device or a fifo.
And it would be perfectly ok for O_DIRECTORY to open such a file, as long as it opens the directory branch, not the special device.
I advocated (long ago) something like this for /dev handling, just because I think it would make sense to have
/dev/hda <- special file /dev/hda/part1 <- partition 1 (aka /dev/hda1)
which just seems like a very obvious and intuitive interface to me. Of course, we have so much legacy in /dev that there's no real point to doing this, but it's still an appealing approach, I think.
But I do take Al's concerns seriously. I like the notion of supporting "containers", but there are undoubtedly serious issues in the notion. I don't strictly know exactly _how_ to implement it sanely (I can talk about using the vfsmnt structure all I like, but the fact is, it's a different thing from a normal mount, and there may be serious problems indeed there).
Still, I really do like the idea of merging the notion of file and directory into one notion of "container". I absolutely _detest_ files with internal structure that tools have to know about (ie I hate seeing all those embedded formats that I can't use "grep" on - MIME being one case). I'd much rather see a "group of files" and a "file with a grouping of information".
(Now, flattening that "group of files" is obviously needed for serial protocols, so I think MIME/tar/xxxx are fine for _transporting_ data, but I'm saying that outside of transport I really prefer a "collection of files" approach).
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