test: integ test for FC-DEV-1903

Signed-off-by: Pablo Barbáchano <pablob@amazon.com>
Signed-off-by: Roman Kovtyukh <HelloDearGrandma@gmail.com>

tests/integration_tests/test_FC-DEV-1903.py

@@ -0,0 +1,49 @@
+import subprocess
+import time
+from pathlib import Path
+
+
+def test_FC_DEV_1903(uvm_plain, microvm_factory):
+    """
+    https://sim.amazon.com/issues/FC-DEV-1903
+
+    Make the test pass
+
+    ./tools/devtool test_debug integration_tests/test_FC-DEV-1903.py
+
+    file:../../src/vmm/src/persist.rs::.dump_dirty(&mut file, &dirty_bitmap)
+    Around here we would have to handle an error:
+      file:../../src/vmm/src/vstate/memory.rs:285
+    """
+    vm_mem_size = 128
+    uvm = uvm_plain
+    uvm.spawn()
+    uvm.basic_config(mem_size_mib=vm_mem_size, track_dirty_pages=True)
+    uvm.add_net_iface()
+    uvm.start()
+    uvm.ssh.run("true")
+
+    chroot = Path(uvm.chroot())
+
+    # Create a large file, so we run out of space (ENOSPC) during the snapshot
+    # Assumes a Docker /srv tmpfs of 1G, derived by trial and error
+    fudge = chroot / "fudge"
+    subprocess.check_call(f"fallocate -l 550M {fudge}", shell=True)
+
+    try:
+        uvm.snapshot_diff()
+    except RuntimeError:
+        msg = "No space left on device"
+        uvm.check_log_message(msg)
+    else:
+        assert False, "This should fail"
+
+    fudge.unlink()
+
+    # Now there is enough space for it to work
+    snap2 = uvm.snapshot_diff()
+
+    vm2 = microvm_factory.build()
+    vm2.spawn()
+    vm2.restore_from_snapshot(snap2, resume=True)
+    vm2.ssh.run("true")

tools/devtool

@@ -309,7 +309,7 @@ run_devctr() {
         --rm \
         --volume /dev:/dev \
         --volume "$FC_ROOT_DIR:$CTR_FC_ROOT_DIR:z" \
-        --tmpfs /srv:exec,dev,size=32G \
+        --tmpfs /srv:exec,dev,size=1G \
         -v /boot:/boot \
         --env PYTHONDONTWRITEBYTECODE=1 \
         "$DEVCTR_IMAGE" "${ctr_args[@]}"