1 files changed, 73 insertions, 16 deletions

diff --git a/block/rbd.c b/block/rbd.c
index 6cd84488e4..1280d66d3c 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -44,6 +44,13 @@
  * leading "\".
  */
 
+/* rbd_aio_discard added in 0.1.2 */
+#if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 2)
+#define LIBRBD_SUPPORTS_DISCARD
+#else
+#undef LIBRBD_SUPPORTS_DISCARD
+#endif
+
 #define OBJ_MAX_SIZE (1UL << OBJ_DEFAULT_OBJ_ORDER)
 
 #define RBD_MAX_CONF_NAME_SIZE 128
@@ -53,13 +60,19 @@
 #define RBD_MAX_SNAP_NAME_SIZE 128
 #define RBD_MAX_SNAPS 100
 
+typedef enum {
+    RBD_AIO_READ,
+    RBD_AIO_WRITE,
+    RBD_AIO_DISCARD
+} RBDAIOCmd;
+
 typedef struct RBDAIOCB {
     BlockDriverAIOCB common;
     QEMUBH *bh;
     int ret;
     QEMUIOVector *qiov;
     char *bounce;
-    int write;
+    RBDAIOCmd cmd;
     int64_t sector_num;
     int error;
     struct BDRVRBDState *s;
@@ -371,7 +384,8 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
 
     r = rcb->ret;
 
-    if (acb->write) {
+    if (acb->cmd == RBD_AIO_WRITE ||
+        acb->cmd == RBD_AIO_DISCARD) {
         if (r < 0) {
             acb->ret = r;
             acb->error = 1;
@@ -605,7 +619,7 @@ static void rbd_aio_bh_cb(void *opaque)
 {
     RBDAIOCB *acb = opaque;
 
-    if (!acb->write) {
+    if (acb->cmd == RBD_AIO_READ) {
         qemu_iovec_from_buffer(acb->qiov, acb->bounce, acb->qiov->size);
     }
     qemu_vfree(acb->bounce);
@@ -616,12 +630,25 @@ static void rbd_aio_bh_cb(void *opaque)
     qemu_aio_release(acb);
 }
 
-static BlockDriverAIOCB *rbd_aio_rw_vector(BlockDriverState *bs,
-                                           int64_t sector_num,
-                                           QEMUIOVector *qiov,
-                                           int nb_sectors,
-                                           BlockDriverCompletionFunc *cb,
-                                           void *opaque, int write)
+static int rbd_aio_discard_wrapper(rbd_image_t image,
+                                   uint64_t off,
+                                   uint64_t len,
+                                   rbd_completion_t comp)
+{
+#ifdef LIBRBD_SUPPORTS_DISCARD
+    return rbd_aio_discard(image, off, len, comp);
+#else
+    return -ENOTSUP;
+#endif
+}
+
+static BlockDriverAIOCB *rbd_start_aio(BlockDriverState *bs,
+                                       int64_t sector_num,
+                                       QEMUIOVector *qiov,
+                                       int nb_sectors,
+                                       BlockDriverCompletionFunc *cb,
+                                       void *opaque,
+                                       RBDAIOCmd cmd)
 {
     RBDAIOCB *acb;
     RADOSCB *rcb;
@@ -633,16 +660,20 @@ static BlockDriverAIOCB *rbd_aio_rw_vector(BlockDriverState *bs,
     BDRVRBDState *s = bs->opaque;
 
     acb = qemu_aio_get(&rbd_aio_pool, bs, cb, opaque);
-    acb->write = write;
+    acb->cmd = cmd;
     acb->qiov = qiov;
-    acb->bounce = qemu_blockalign(bs, qiov->size);
+    if (cmd == RBD_AIO_DISCARD) {
+        acb->bounce = NULL;
+    } else {
+        acb->bounce = qemu_blockalign(bs, qiov->size);
+    }
     acb->ret = 0;
     acb->error = 0;
     acb->s = s;
     acb->cancelled = 0;
     acb->bh = NULL;
 
-    if (write) {
+    if (cmd == RBD_AIO_WRITE) {
         qemu_iovec_to_buffer(acb->qiov, acb->bounce);
     }
 
@@ -664,10 +695,18 @@ static BlockDriverAIOCB *rbd_aio_rw_vector(BlockDriverState *bs,
         goto failed;
     }
 
-    if (write) {
+    switch (cmd) {
+    case RBD_AIO_WRITE:
         r = rbd_aio_write(s->image, off, size, buf, c);
-    } else {
+        break;
+    case RBD_AIO_READ:
         r = rbd_aio_read(s->image, off, size, buf, c);
+        break;
+    case RBD_AIO_DISCARD:
+        r = rbd_aio_discard_wrapper(s->image, off, size, c);
+        break;
+    default:
+        r = -EINVAL;
     }
 
     if (r < 0) {
@@ -690,7 +729,8 @@ static BlockDriverAIOCB *qemu_rbd_aio_readv(BlockDriverState *bs,
                                             BlockDriverCompletionFunc *cb,
                                             void *opaque)
 {
-    return rbd_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
+    return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
+                         RBD_AIO_READ);
 }
 
 static BlockDriverAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs,
@@ -700,7 +740,8 @@ static BlockDriverAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs,
                                              BlockDriverCompletionFunc *cb,
                                              void *opaque)
 {
-    return rbd_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
+    return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
+                         RBD_AIO_WRITE);
 }
 
 static int qemu_rbd_co_flush(BlockDriverState *bs)
@@ -850,6 +891,18 @@ static int qemu_rbd_snap_list(BlockDriverState *bs,
     return snap_count;
 }
 
+#ifdef LIBRBD_SUPPORTS_DISCARD
+static BlockDriverAIOCB* qemu_rbd_aio_discard(BlockDriverState *bs,
+                                              int64_t sector_num,
+                                              int nb_sectors,
+                                              BlockDriverCompletionFunc *cb,
+                                              void *opaque)
+{
+    return rbd_start_aio(bs, sector_num, NULL, nb_sectors, cb, opaque,
+                         RBD_AIO_DISCARD);
+}
+#endif
+
 static QEMUOptionParameter qemu_rbd_create_options[] = {
     {
      .name = BLOCK_OPT_SIZE,
@@ -880,6 +933,10 @@ static BlockDriver bdrv_rbd = {
     .bdrv_aio_writev        = qemu_rbd_aio_writev,
     .bdrv_co_flush_to_disk  = qemu_rbd_co_flush,
 
+#ifdef LIBRBD_SUPPORTS_DISCARD
+    .bdrv_aio_discard       = qemu_rbd_aio_discard,
+#endif
+
     .bdrv_snapshot_create   = qemu_rbd_snap_create,
     .bdrv_snapshot_delete   = qemu_rbd_snap_remove,
     .bdrv_snapshot_list     = qemu_rbd_snap_list,