[PATCH 3/4] tests/qtest/virtio-scsi: cover a replacement that changes the size

["Denis V. Lunev" <den@openvz.org>]

Realize a scsi-hd on a 1 MiB node, replace it with a 128 MiB one using
qom-set, and check that the device reports CAPACITY DATA HAS CHANGED and
then serves a read which only fits in the new node.

Both halves regress on their own. Without the notification from
bdrv_replace_child_bs() the first command after the replacement fails with
ILLEGAL REQUEST / LOGICAL BLOCK ADDRESS OUT OF RANGE instead of the unit
attention. Without the refresh in scsi_disk_resize_cb() the read after it
is refused the same way, since nothing here issues READ CAPACITY.

Signed-off-by: Denis V. Lunev <den@openvz.org>
---
 tests/qtest/virtio-scsi-test.c | 63 ++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/tests/qtest/virtio-scsi-test.c b/tests/qtest/virtio-scsi-test.c
index e2350c52f6..f82b7e5de9 100644
--- a/tests/qtest/virtio-scsi-test.c
+++ b/tests/qtest/virtio-scsi-test.c
@@ -236,6 +236,53 @@ static void test_unmap_large_lba(void *obj, void *data,
     qvirtio_scsi_pci_free(vs);
 }
 
+/* Test replacing the backing node with one of a different size */
+static void test_replaced_node_size(void *obj, void *data,
+                                    QGuestAllocator *t_alloc)
+{
+    QVirtioSCSI *scsi = obj;
+    QVirtioSCSIQueues *vs;
+    uint8_t buf[512] = { 0 };
+    /* READ(10), LBA 0, transfer length 1 */
+    const uint8_t read_low_cdb[VIRTIO_SCSI_CDB_SIZE] = {
+        0x28, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00
+    };
+    /* READ(10), LBA 0x1000 (2 MiB), transfer length 1 */
+    const uint8_t read_high_cdb[VIRTIO_SCSI_CDB_SIZE] = {
+        0x28, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x01, 0x00
+    };
+    struct virtio_scsi_cmd_resp resp;
+
+    alloc = t_alloc;
+    vs = qvirtio_scsi_init(scsi->vdev);
+
+    /* LBA 0 is inside the 1 MiB node the device was realized with */
+    virtio_scsi_do_command(vs, read_low_cdb, buf, sizeof(buf), NULL, 0, &resp);
+    g_assert_cmphex(resp.response, ==, 0);
+    g_assert_cmphex(resp.status, ==, GOOD);
+
+    /* Swap in a 128 MiB node; the device is not reset by this */
+    qtest_qmp_assert_success(global_qtest,
+                             "{'execute': 'qom-set', 'arguments': {"
+                             "  'path': '/machine/peripheral/scsi-hd0',"
+                             "  'property': 'drive', 'value': 'big'}}");
+
+    /* The guest has to be told that the capacity it knows is stale */
+    virtio_scsi_do_command(vs, read_high_cdb, buf, sizeof(buf), NULL, 0, &resp);
+    g_assert_cmphex(resp.response, ==, 0);
+    g_assert_cmphex(resp.status, ==, CHECK_CONDITION);
+    g_assert_cmphex(resp.sense[2], ==, UNIT_ATTENTION);
+    g_assert_cmphex(resp.sense[12], ==, 0x2a);
+    g_assert_cmphex(resp.sense[13], ==, 0x09); /* CAPACITY DATA HAS CHANGED */
+
+    /* LBA 0x1000 is past the old node but well inside the new one */
+    virtio_scsi_do_command(vs, read_high_cdb, buf, sizeof(buf), NULL, 0, &resp);
+    g_assert_cmphex(resp.response, ==, 0);
+    g_assert_cmphex(resp.status, ==, GOOD);
+
+    qvirtio_scsi_pci_free(vs);
+}
+
 static void test_write_to_cdrom(void *obj, void *data,
                                 QGuestAllocator *t_alloc)
 {
@@ -365,6 +412,18 @@ static void *virtio_scsi_setup_4k(GString *cmd_line, void *arg)
     return arg;
 }
 
+static void *virtio_scsi_setup_replace(GString *cmd_line, void *arg)
+{
+    g_string_append(cmd_line,
+                    " -blockdev driver=null-co,read-zeroes=on,"
+                    "size=1048576,node-name=small"
+                    " -blockdev driver=null-co,read-zeroes=on,"
+                    "size=134217728,node-name=big"
+                    " -device scsi-hd,id=scsi-hd0,drive=small,"
+                    "lun=0,scsi-id=1");
+    return arg;
+}
+
 static void *virtio_scsi_setup_cd(GString *cmd_line, void *arg)
 {
     g_string_append(cmd_line,
@@ -399,6 +458,10 @@ static void register_virtio_scsi_test(void)
     qos_add_test("large-lba-unmap", "virtio-scsi",
                  test_unmap_large_lba, &opts);
 
+    opts.before = virtio_scsi_setup_replace;
+    qos_add_test("replaced-node-size", "virtio-scsi",
+                 test_replaced_node_size, &opts);
+
     opts.before = virtio_scsi_setup_cd;
     qos_add_test("write-to-cdrom", "virtio-scsi", test_write_to_cdrom, &opts);
 
-- 
2.53.0