On Tue, Sep 27, 2016 at 06:43:35PM +0200, Jan Kara wrote:
> Currently each filesystem (possibly through generic_file_direct_write()
> or iomap_dax_rw()) takes care of invalidating page tables and evicting
> hole pages from the radix tree when write(2) to the file happens. This
> invalidation is only necessary when there is some block allocation
> resulting from write(2). Furthermore in current place the invalidation
> is racy wrt page fault instantiating a hole page just after we have
> invalidated it.
>
> So perform the page invalidation inside dax_do_io() where we can do it
> only when really necessary and after blocks have been allocated so
> nobody will be instantiating new hole pages anymore.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
This looks fine with the comment from Dave addressed:
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> + if (buffer_new(bh) &&
> + inode->i_mapping->nrpages) {
Btw, it would be nice if the nrpages check could move into
invalidate_inode_pages2_range instead of having to bother with it in
the callers.
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