Hi,
On Wed, Jul 26, 2000 at 02:41:44PM -0400, Alexander Viro wrote:
> > For tail writes, I'd imagine we would just end up using the page cache
> > as a virtual cache as NFS uses it, and doing plain copy into the
> > buffer cache pages.
>
> Ouch. I _really_ don't like it - we end up with special behaviour on one
> page in the pagecache.
Correct. But it's all inside the filesystem, so there is zero VFS
impact. And we're talking about non-block-aligned data for tails, so
we simply don't have a choice in this case.
> And getting data migration from buffer cache to
> page cache, which is Not Nice(tm).
Not preferred for bulk data, perhaps, but the VFS should cope just
fine.
> Yuck... Besides, when do we decide that
> tail is going to be, erm, merged? What will happen with the page then?
To the page? Nothing. To the buffer? It gets updated with the new
contents of disk. Page == virtual contents. Buffer == physical
contents. Plain and simple.
Cheers,
Stephen
