Steve Lord wrote:
>
> Hi Andrew,
>
> I ran into a problem with 2.5's O_DIRECT read path,
>
> generic_file_direct_IO usually ends up in generic_direct_IO
> this does bounds checking on the I/O and then flushes any
> cached data.
>
> Once we return to generic_file_direct_IO we unconditionally
> call invalidate_inode_pages2 if there are any cached pages.
>
> If we make a non-aligned O_DIRECT read call, the end result is we
> call invalidate_inode_pages2, but we do not do the filemap_fdatawrite,
> filemap_fdatawait calls. End result is we throw the buffered data away.
Well you could always switch to Linus' current BK tree, in
which invalidate_inode_pages2() is a no-op (whoops).
> Either the flush needs to happen before the bounds checks, or the
> invalidate should only be done on a successful write. It looks
> pretty hard to detect the latter case with the current structure,
> we can get EINVAL from the bounds check and possibly from an
> aligned, but invalid memory address being passed in.
Yes I agree; let's just do the sync before any checks.
I think it should be moved into generic_file_direct_IO(),
because that's the place where the invalidation happens, yes?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon Oct 07 2002 - 22:00:47 EST