nbd: add support for NBD_CMD_TRIM

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/block/nbd.c b/block/nbd.c
index 097b4188e5..161b299855 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -435,6 +435,30 @@ static int nbd_co_flush(BlockDriverState *bs)
     return -reply.error;
 }
 
+static int nbd_co_discard(BlockDriverState *bs, int64_t sector_num,
+                          int nb_sectors)
+{
+    BDRVNBDState *s = bs->opaque;
+    struct nbd_request request;
+    struct nbd_reply reply;
+
+    if (!(s->nbdflags & NBD_FLAG_SEND_TRIM)) {
+        return 0;
+    }
+    request.type = NBD_CMD_TRIM;
+    request.from = sector_num * 512;;
+    request.len = nb_sectors * 512;
+
+    nbd_coroutine_start(s, &request);
+    if (nbd_co_send_request(s, &request, NULL, 0) == -1) {
+        reply.error = errno;
+    } else {
+        nbd_co_receive_reply(s, &request, &reply, NULL, 0);
+    }
+    nbd_coroutine_end(s, &request);
+    return -reply.error;
+}
+
 static void nbd_close(BlockDriverState *bs)
 {
     BDRVNBDState *s = bs->opaque;
@@ -459,6 +483,7 @@ static BlockDriver bdrv_nbd = {
     .bdrv_co_writev      = nbd_co_writev,
     .bdrv_close          = nbd_close,
     .bdrv_co_flush_to_os = nbd_co_flush,
+    .bdrv_co_discard     = nbd_co_discard,
     .bdrv_getlength      = nbd_getlength,
     .protocol_name       = "nbd",
 };