Re: Merging relayfs?

[Greg KH <greg@kroah.com>]

On Mon, Jul 11, 2005 at 11:52:57PM -0400, Karim Yaghmour wrote:
> 
> Greg KH wrote:
> > Based on the proposed users of this fs, I don't see any.  What ones are
> > you saying are not "debug" type operations?  And yes, I consider LTT a
> > "debug" type operation :)
> > 
> > The best part of this, is it gives distros and users a consistant place
> > to mount the fs, and to know where this kind of thing shows up in the fs
> > namespace.
> 
> Except that relayfs contains files that all behave in a very specific
> way: as relayfs buffers, while debugfs may contain a variety of different
> types of files.

The path/filename dictates how it is used, so putting relayfs type files
in debugfs is just fine.  debugfs allows any types of files to be there.

> I kind'a see what you're trying to say, and I fully understand that some
> debugfs users may indeed use the relayfs fileops to add an entry in
> debugfs which serves as a buffer, and that's the very reason we exported
> them to boot.

Good.

> But there's something to be said about having a single filesystem (and
> therefore tree somewhere in /)

New trees in / are not LSB compliant, hence the reason for writing
securityfs to get rid of /selinux and other LSM filesystems that were
starting to sprout up.

> which contains entries dedicated to a single purpose: dump huge
> amounts of data out of the kernel and into userspace whether or not
> the system is being debuged.

But that's exactly what debugfs is for, to allow data to be dumped out
of the kernel for different usages.

> From a user point of view, it sounds awfully weird if they're using
> "debugfs" on a production system ...

Ok, have a better name for it?  It's simple and easy to understand.

> > Last I looked, this was not possible.  Has this changed in the latest
> > version?
> 
> Here's from 2.6.13-rc2-mm1 fs/relayfs/inode.c
> > +EXPORT_SYMBOL_GPL(relayfs_open);
> > +EXPORT_SYMBOL_GPL(relayfs_poll);
> > +EXPORT_SYMBOL_GPL(relayfs_mmap);
> > +EXPORT_SYMBOL_GPL(relayfs_release);
> > +EXPORT_SYMBOL_GPL(relayfs_file_operations);
> > +EXPORT_SYMBOL_GPL(relayfs_create_dir);
> > +EXPORT_SYMBOL_GPL(relayfs_remove_dir);
> 
> It's been there ever since you've asked for it earlier this year :)

Thanks, didn't realize that.  Wait, all that should be needed is
"relayfs_file_operations", right?  Why have those others exported?

thanks,

greg k-h