Add test for maximum SMB valid pwrite range (#15011)

We need to validate we can write above 16 TiB offset and that
we get properly stopped writing about 64 TiB offset.

(cherry picked from commit 2655712)

Co-authored-by: Andrew Walker <[email protected]>

tests/api2/test_smb_write_offset.py

@@ -0,0 +1,67 @@
+import os
+import pytest
+import random
+
+from middlewared.test.integration.assets.account import user, group
+from middlewared.test.integration.assets.pool import dataset
+from middlewared.test.integration.assets.smb import smb_share
+from middlewared.test.integration.utils import call
+
+from protocols import smb_connection
+
+from samba import ntstatus
+from samba import NTSTATUSError
+
+SHARE_NAME = 'offset_test'
+
+LARGE_OFFSET = 0x0000140000000000
+INVALID_OFFSET = 0x0000410000000000
+
+
+@pytest.fixture(scope='module')
+def setup_smb_tests():
+    with dataset('smbclient-testing', data={'share_type': 'SMB'}) as ds:
+        with user({
+            'username': 'smbuser',
+            'full_name': 'smbuser',
+            'group_create': True,
+            'password': 'Abcd1234'
+        }) as u:
+            with smb_share(os.path.join('/mnt', ds), SHARE_NAME) as s:
+                try:
+                    call('service.start', 'cifs')
+                    yield (ds, s, u)
+                finally:
+                    call('service.stop', 'cifs')
+
+
+def test_valid_offset(setup_smb_tests):
+    ds, share, smb_user = setup_smb_tests
+    with smb_connection(
+        share=SHARE_NAME,
+        username=smb_user['username'],
+        password='Abcd1234',
+        smb1=False
+    ) as c:
+        fd = c.create_file('file_valid_offset', 'w')
+        buf = random.randbytes(1024)
+
+        c.write(fd, offset=LARGE_OFFSET, data=buf)
+        out = c.read(fd, offset=LARGE_OFFSET, cnt=1024)
+        assert buf == out
+
+
+def test_invalid_offset(setup_smb_tests):
+    ds, share, smb_user = setup_smb_tests
+    with smb_connection(
+        share=SHARE_NAME,
+        username=smb_user['username'],
+        password='Abcd1234',
+        smb1=False
+    ) as c:
+        fd = c.create_file('file_valid_offset', 'w')
+
+        with pytest.raises(NTSTATUSError) as nt_err:
+            c.write(fd, offset=INVALID_OFFSET, data=b'CANARY')
+
+        assert nt_err.value.args[0] == ntstatus.NT_STATUS_INVALID_PARAMETER