In message <[EMAIL PROTECTED]>, [EMAIL PROTECTED] writes:
> On Mon, May 01, 2000 at 06:25:43PM +0200, Peter Schneider-Kamp wrote:
> > I second that. I had to stop maintaining the steganographic file
> > system around 2.3.7 because I did not have that much time to
> > find out where my fs is "broken" and needs to be "fixed".
>
> FYI, the changes which broke filesystems in 2.3.8 were page cache /
> buffer cache changes and as such were VM changes, not VFS. They were
> a major change that was required to make Linux more scalable.
Ideally, developing file systems would involve only the VFS. In practice,
in involves the VM as well. I've worked on stacking interfaces for several
different OSs, and as much as they all want the VFS and VM to be two
completely separate entities, in practice they are not. About half of the
effort I spent on my stacking templates was related to the VM and changes to
the VM (linux/mm/*.c). IOW, most people who maintain file systems must
track changes in both the VFS and the VM.
That said, I'm quite pleased with the changes that happened in late 2.3.40s:
breaking some into address_space ops and more. IMHO the separation b/t the
VFS and the VM became more clear then, and it allowed me to cleanup my
stacking code quite nicely, as well as make easy use of vfs_<op> calls,
generic_file_{read,write}, and more.
Erez.
