Fix synchronicity for ZVOLs.

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

diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index 9dda040..0aaa268 100644 (file)
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -534,6 +534,17 @@ zvol_write(void *arg)
        dmu_tx_t *tx;
        rl_t *rl;
 
+       if (req->cmd_flags & VDEV_REQ_FLUSH)
+               zil_commit(zv->zv_zilog, ZVOL_OBJ);
+
+       /*
+        * Some requests are just for flush and nothing else.
+        */
+       if (size == 0) {
+               blk_end_request(req, 0, size);
+               return;
+       }
+
        rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_WRITER);
 
        tx = dmu_tx_create(zv->zv_objset);
@@ -550,12 +561,14 @@ zvol_write(void *arg)
 
        error = dmu_write_req(zv->zv_objset, ZVOL_OBJ, req, tx);
        if (error == 0)
-               zvol_log_write(zv, tx, offset, size, rq_is_sync(req));
+               zvol_log_write(zv, tx, offset, size,
+                   req->cmd_flags & VDEV_REQ_FUA);
 
        dmu_tx_commit(tx);
        zfs_range_unlock(rl);
 
-       if (rq_is_sync(req) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS)
+       if ((req->cmd_flags & VDEV_REQ_FUA) ||
+           zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS)
                zil_commit(zv->zv_zilog, ZVOL_OBJ);
 
        blk_end_request(req, -error, size);
@@ -578,6 +591,11 @@ zvol_read(void *arg)
        int error;
        rl_t *rl;
 
+       if (size == 0) {
+               blk_end_request(req, 0, size);
+               return;
+       }
+
        rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_READER);
 
        error = dmu_read_req(zv->zv_objset, ZVOL_OBJ, req);
@@ -627,7 +645,7 @@ zvol_request(struct request_queue *q)
        while ((req = blk_fetch_request(q)) != NULL) {
                size = blk_rq_bytes(req);
 
-               if (blk_rq_pos(req) + blk_rq_sectors(req) >
+               if (size != 0 && blk_rq_pos(req) + blk_rq_sectors(req) >
                    get_capacity(zv->zv_disk)) {
                        printk(KERN_INFO
                               "%s: bad access: block=%llu, count=%lu\n",
@@ -1062,6 +1080,12 @@ zvol_alloc(dev_t dev, const char *name)
        if (zv->zv_queue == NULL)
                goto out_kmem;
 
+#ifdef HAVE_BLK_QUEUE_FLUSH
+       blk_queue_flush(zv->zv_queue, VDEV_REQ_FLUSH | VDEV_REQ_FUA);
+#else
+       blk_queue_ordered(zv->zv_queue, QUEUE_ORDERED_DRAIN, NULL);
+#endif /* HAVE_BLK_QUEUE_FLUSH */
+
        zv->zv_disk = alloc_disk(ZVOL_MINORS);
        if (zv->zv_disk == NULL)
                goto out_queue;