Add support for DISCARD to ZVOLs.

[zfs.git] / module / zfs / zvol.c

diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index 19888ea..9b13134 100644 (file)
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -574,6 +574,42 @@ zvol_write(void *arg)
        blk_end_request(req, -error, size);
 }
 
+#ifdef HAVE_BLK_QUEUE_DISCARD
+static void
+zvol_discard(void *arg)
+{
+       struct request *req = (struct request *)arg;
+       struct request_queue *q = req->q;
+       zvol_state_t *zv = q->queuedata;
+       uint64_t offset = blk_rq_pos(req) << 9;
+       uint64_t size = blk_rq_bytes(req);
+       int error;
+       rl_t *rl;
+
+       if (offset + size > zv->zv_volsize) {
+               blk_end_request(req, -EIO, size);
+               return;
+       }
+
+       if (size == 0) {
+               blk_end_request(req, 0, size);
+               return;
+       }
+
+       rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_WRITER);
+
+       error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, offset, size);
+
+       /*
+        * TODO: maybe we should add the operation to the log.
+        */
+
+       zfs_range_unlock(rl);
+
+       blk_end_request(req, -error, size);
+}
+#endif /* HAVE_BLK_QUEUE_DISCARD */
+
 /*
  * Common read path running under the zvol taskq context.  This function
  * is responsible for copying the requested data out of the DMU and in to
@@ -674,6 +710,13 @@ zvol_request(struct request_queue *q)
                                break;
                        }
 
+#ifdef HAVE_BLK_QUEUE_DISCARD
+                       if (req->cmd_flags & VDEV_REQ_DISCARD) {
+                               zvol_dispatch(zvol_discard, req);
+                               break;
+                       }
+#endif /* HAVE_BLK_QUEUE_DISCARD */
+
                        zvol_dispatch(zvol_write, req);
                        break;
                default:
@@ -1193,6 +1236,10 @@ __zvol_create_minor(const char *name)
        blk_queue_max_segment_size(zv->zv_queue, UINT_MAX);
        blk_queue_physical_block_size(zv->zv_queue, zv->zv_volblocksize);
        blk_queue_io_opt(zv->zv_queue, zv->zv_volblocksize);
+#ifdef HAVE_BLK_QUEUE_DISCARD
+       blk_queue_max_discard_sectors(zv->zv_queue, UINT_MAX);
+       queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zv->zv_queue);
+#endif
 #ifdef HAVE_BLK_QUEUE_NONROT
        queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zv->zv_queue);
 #endif