Commit 7d06bbb2d9 for qemu.org
commit 7d06bbb2d9ba77e45b5a3131c9e7f934df99d5bc
Author: Fiona Ebner <f.ebner@proxmox.com>
Date: Thu Jul 2 15:22:36 2026 +0200
iotests: test O_TRUNC behavior for fuse exports
The test cases for the blockdev-based export and for the file-based
export with growable=on work before commit a94a1d7699 ("fuse: Manually
process requests (without libfuse)"), then are broken until commit
"block/export/fuse: fix regression with O_TRUNC when export is
growable".
The test case for the blockdev-based export requires passwordless sudo
for losetup and chmod similar to test 108.
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Message-ID: <20260702132256.661429-3-f.ebner@proxmox.com>
[kwolf: Catch OSError when probing sudo support]
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/tests/qemu-iotests/tests/fuse-truncate b/tests/qemu-iotests/tests/fuse-truncate
new file mode 100755
index 0000000000..7eee35111c
--- /dev/null
+++ b/tests/qemu-iotests/tests/fuse-truncate
@@ -0,0 +1,171 @@
+#!/usr/bin/env python3
+# group: rw
+#
+# Test how fuse exports behave with regard to O_TRUNC.
+#
+# Copyright (C) 2026 Proxmox Server Solutions GmbH
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+import os
+import subprocess
+from pathlib import Path
+
+import iotests
+from iotests import qemu_img, QemuStorageDaemon
+
+fuse_mount_point = os.path.join(iotests.test_dir, 'export.fuse')
+image_size = 1 * 1024 * 1024
+image = os.path.join(iotests.test_dir, 'image.' + iotests.imgfmt)
+
+def check_fuse_support():
+ Path(fuse_mount_point).touch()
+ test_qsd = QemuStorageDaemon('--blockdev', 'null-co,node-name=node0',
+ qmp=True)
+ res = test_qsd.qmp('block-export-add', {
+ 'id': 'exp0',
+ 'type': 'fuse',
+ 'node-name': 'node0',
+ 'mountpoint': fuse_mount_point,
+ 'allow-other': 'off'
+ })
+ test_qsd.stop()
+ os.remove(fuse_mount_point)
+ if 'error' in res:
+ assert (res['error']['desc'] ==
+ "Parameter 'type' does not accept value 'fuse'")
+ iotests.notrun('No FUSE support')
+
+def check_sudo_support():
+ try:
+ subprocess.run(['sudo', '-n', 'losetup', '--version'],
+ capture_output=True, check=True)
+ except (OSError, subprocess.CalledProcessError):
+ return False
+ try:
+ subprocess.run(['sudo', '-n', 'chmod', '--version'],
+ capture_output=True, check=True)
+ except (OSError, subprocess.CalledProcessError):
+ return False
+ return True
+
+check_fuse_support()
+
+class TestTruncateBase(iotests.QMPTestCase):
+ growable = False
+ supports_preconditions = True
+
+ def evaluate_preconditions(self):
+ return
+
+ def add_blockdev(self):
+ qemu_img('create', '-f', iotests.imgfmt, image, str(image_size))
+ self.qsd.cmd('blockdev-add', {
+ 'node-name': 'node0',
+ 'driver': iotests.imgfmt,
+ 'file': {
+ 'driver': 'file',
+ 'filename': image
+ }
+ })
+
+ def cleanup_blockdev(self):
+ os.remove(image)
+
+ def add_export(self):
+ self.qsd.cmd('block-export-add', {
+ 'id': 'exp0',
+ 'type': 'fuse',
+ 'node-name': 'node0',
+ 'mountpoint': fuse_mount_point,
+ 'growable': self.growable,
+ 'writable': True,
+ 'allow-other': 'off'
+ })
+
+ def stop_qsd(self):
+ if self.qsd:
+ self.qsd.cmd('block-export-del', {'id': 'exp0'})
+ self.qsd.stop()
+ self.qsd = None
+
+ def setUp(self):
+ self.evaluate_preconditions()
+ if not self.supports_preconditions:
+ return
+ Path(fuse_mount_point).touch()
+ self.qsd = QemuStorageDaemon(qmp=True)
+ self.add_blockdev()
+ self.add_export()
+
+ def tearDown(self):
+ if not self.supports_preconditions:
+ return
+ self.stop_qsd()
+ self.cleanup_blockdev()
+ os.remove(fuse_mount_point)
+
+class TestTruncateFileGrowable(TestTruncateBase):
+ growable = True
+
+ def test_o_trunc(self):
+ with open(fuse_mount_point, 'w+b') as file:
+ file.seek(0, os.SEEK_END)
+ self.assertEqual(file.tell(), 0)
+ file.write(b"test")
+ self.stop_qsd()
+
+class TestTruncateFileNotGrowable(TestTruncateBase):
+ growable = False
+
+ def test_o_trunc(self):
+ with open(fuse_mount_point, 'w+b') as file:
+ file.seek(0, os.SEEK_END)
+ self.assertEqual(file.tell(), image_size)
+ file.seek(0, os.SEEK_SET)
+ file.write(b"test")
+ self.stop_qsd()
+
+class TestTruncateBlockdev(TestTruncateBase):
+ growable = False
+
+ def evaluate_preconditions(self):
+ self.supports_preconditions = check_sudo_support()
+
+ def add_blockdev(self):
+ qemu_img('create', '-f', iotests.imgfmt, image, str(image_size))
+ res = subprocess.run(['sudo', '-n', 'losetup', '--show', '-f', image],
+ check=True, capture_output=True, text=True)
+ self.loopdev = res.stdout.strip()
+ subprocess.run(['sudo', '-n', 'chmod', 'go+rw', self.loopdev],
+ check=True, capture_output=True)
+ self.qsd.cmd('blockdev-add', {
+ 'node-name': 'node0',
+ 'driver': iotests.imgfmt,
+ 'file': {
+ 'driver': 'host_device',
+ 'filename': self.loopdev
+ }
+ })
+
+ def cleanup_blockdev(self):
+ subprocess.run(['sudo', '-n', 'losetup', '--detach', self.loopdev],
+ check=True, capture_output=True)
+ os.remove(image)
+
+ def test_o_trunc(self):
+ if not self.supports_preconditions:
+ iotests.case_notrun('No passwordless sudo for losetup and chmod')
+ return
+
+ with open(fuse_mount_point, 'w+b') as file:
+ file.seek(0, os.SEEK_END)
+ self.assertEqual(file.tell(), image_size)
+ file.seek(0, os.SEEK_SET)
+ file.write(b"test")
+ self.stop_qsd()
+
+if __name__ == '__main__':
+ iotests.main(supported_fmts=['raw'],
+ supported_protocols=['file'],
+ supported_platforms=['linux'])
diff --git a/tests/qemu-iotests/tests/fuse-truncate.out b/tests/qemu-iotests/tests/fuse-truncate.out
new file mode 100644
index 0000000000..8d7e996700
--- /dev/null
+++ b/tests/qemu-iotests/tests/fuse-truncate.out
@@ -0,0 +1,5 @@
+...
+----------------------------------------------------------------------
+Ran 3 tests
+
+OK