On Thu, Nov 02, 2006 at 09:58:58AM +1100, David Chinner wrote:
[ ...]
Thanks for the review, I'll incorporate these suggestions into the next
patch set.
> > +
> > + /*
> > + * the placeholder code does filemap_write_and_wait, so if we
> > + * aren't using placeholders we have to do it here
> > + */
> > + if (!(dio->flags & DIO_PLACEHOLDERS) && end > offset) {
> > + struct address_space *mapping = iocb->ki_filp->f_mapping;
> > retval = filemap_write_and_wait_range(mapping, offset, end - 1);
> > if (retval)
> > goto out;
>
> So that means XFS will now do three cache flushes on write (one in
> xfs_write(), one in generic_file_direct_IO() and yet another here....
I removed the flush before starting the IO in generic_file_direct_IO
because that is now done by the placeholders. When placeholders aren't
used, we need the flush to match the old behavior.
I added the flush in generic_file_direct_IO after calling the direct_IO
func because invalidate_page_range2 requires the data to be flushed
first. Otherwise it fails to free a dirty page with dirty buffers and
spits out -EIO. This only happens when mapping->nrpages > 0, so it
should be very low cost in the common case.
It's messy, I'll try to refactor things a bit to make it cleaner (same
goes for i_mutex drop/lock).
-chris
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