7c5465d6cc
As discussed earlier, it is better for block client to allocate memory for tracking extents state before submitting bio. So the patch does it by allocating a short_extent for every INVALID extent touched by write pagelist and for every zeroing page we created, saving them in layout header. Then in end_io we can just use them to create commit list items and avoid memory allocation there. Signed-off-by: Peng Tao <peng_tao@emc.com> Signed-off-by: Benny Halevy <bhalevy@tonian.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>