Re: hundreds of mount --bind mountpoints?

Richard Gooch
2001-04-23T21:20:11Z

Ingo Oeser writes:
> On Mon, Apr 23, 2001 at 11:36:24AM -0400, Alexander Viro wrote:
> > > Great idea. We allocate this space anyway. And we don't have to
> > > care about the internals of this union, because never have to use
> > > it outside the kernel ;-)
> > >
> > > I like it. ext2fs does the same, so there should be no VFS
> > > hassles involved. Al?
> >
> > We should get ext2 and friends to move the sucker _out_ of struct inode.
> > As it is, sizeof(struct inode) is way too large. This is 2.5 stuff, but
> > it really has to be done. More filesystems adding stuff into the union
> > is a Bad Thing(tm). If you want to allocates space - allocate if yourself;
> > ->clear_inode() is the right place for freeing it.
>
> You need an inode anyway. So why not using the space in it? tmpfs
> would only use sizeof(*inode.u)-sizeof(struct shmem_inode_info) for
> this kind of symlinks.
>
> Last time we suggested this, people ended up with some OS trying
> it and getting worse performance.
>
> Why? You need to allocate the VFS-inode (vnode in other OSs) and
> the on-disk-inode anyway at the same time. You get better
> performance and less fragmentation, if you allocate them both
> together[1].

We want to take out that union because it sucks for virtual
filesystems. Besides, it's ugly.

Regards,

Richard....
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