Re: [Libguestfs] [PATCH libnbd 2/2] examples: copy-libev.c: Simple sparsifying

If a request includes only zeroes, use efficient zero method instead of sending the zeroes over the wire. Signed-off-by: Nir Soffer <nsoffer(a)redhat.com&gt; --- examples/Makefile.am | 1 + examples/copy-libev.c | 68 ++++++++++++++++++++++++++++++++++--------- 2 files changed, 55 insertions(+), 14 deletions(-)

+static void +start_zero(struct request *r) +{ + int64_t cookie; + + DEBUG ("start zero offset=%ld len=%ld", r->offset, r->length); + + cookie = nbd_aio_zero ( + dst.nbd, r->length, r->offset, + (nbd_completion_callback) { .callback=request_completed, + .user_data=r }, + 0); + if (cookie == -1) + FAIL ("Cannot start zero: %s", nbd_get_error ());