Am Thu, 14 Feb 2008 16:00:06 +0100 (CET) schrieb Jan Engelhardt <[EMAIL PROTECTED]>:
> > On Feb 14 2008 10:46, Andi Kleen wrote: > >Jasper Bryant-Greene <[EMAIL PROTECTED]> writes: > >> > >> This could be done fairly trivially with FUSE, and IMHO is a good > >> use for FUSE because since you're just throwing most data away, > >> performance is not a concern. > > There is a much more interesting 'problem' with a "/dev/null > directory". > > Q: Why would you need such a directory? > A: To temporarily fool a program into believing it wrote something. > > Q: Should all files disappear? (e.g. "unlink after open") > A: Maybe not, programs may stat() the file right afterwards and > get confused by the "inexistence". > > Q: What if a program attempts to mkdir /dev/nullmnt/foo to just > create a file /dev/nullmnt/foo/barfile? > A: /dev/nullmnt/foo must continue to exist or be accepted for a while, > or perhaps for eternity. Well, the problem seems to be that a "directory" is not just data but also contains metadata. While it's easy to write data to /dev/null, you cannot simply discard metadata associated with a directory. So, such a "/dev/null-directory" would have to remember metadata (at least all created filenames including subdirectories) in the same way as other filesystems do. Only file _content_ can be discarded. To be honest, I still cannot see many sensible usecases for that... Thanks, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
