This test would have worked before commit 8599559580 ("fuse: Set
direct_io and parallel_direct_writes") and is working again since
commit HEAD~1 ("block/export/fuse: set FUSE_DIRECT_IO_ALLOW_MMAP flag
to fix regression").Signed-off-by: Fiona Ebner <[email protected]> --- tests/qemu-iotests/tests/fuse-mmap-shared | 103 ++++++++++++++++++ tests/qemu-iotests/tests/fuse-mmap-shared.out | 5 + 2 files changed, 108 insertions(+) create mode 100755 tests/qemu-iotests/tests/fuse-mmap-shared create mode 100644 tests/qemu-iotests/tests/fuse-mmap-shared.out diff --git a/tests/qemu-iotests/tests/fuse-mmap-shared b/tests/qemu-iotests/tests/fuse-mmap-shared new file mode 100755 index 0000000000..a0a10cea6a --- /dev/null +++ b/tests/qemu-iotests/tests/fuse-mmap-shared @@ -0,0 +1,103 @@ +#!/usr/bin/env python3 +# group: rw +# +# Test that a FUSE export can be mmap()-ed with MAP_SHARED +# +# Copyright (C) 2026 Proxmox Server Solutions GmbH +# +# SPDX-License-Identifier: GPL-2.0-or-later + +import os +import itertools +import mmap +from mmap import MAP_SHARED +from pathlib import Path + +import iotests +from iotests import qemu_img, qemu_io, QemuStorageDaemon + +def test_fuse_support(mount_point): + 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': mount_point, + 'allow-other': 'off' + }) + test_qsd.stop() + if 'error' in res: + assert (res['error']['desc'] == + "Parameter 'type' does not accept value 'fuse'") + iotests.notrun('No FUSE support') + +# Shared mmap when using direct IO is only supported for Linux kernels >= 6.6 +# with commit e78662e818f94 ("fuse: add a new fuse init flag to relax +# estrictions in no cache mode"). +def test_linux_kernel_support(): + [major, minor] = map(int, os.uname().release.split('.')[:2]) + if major < 6 or (major == 6 and minor < 6): + iotests.notrun('No kernel support for shared mmap with direct IO') + +image_size = 1 * 1024 * 1024 +image = os.path.join(iotests.test_dir, 'image.' + iotests.imgfmt) +fuse_mount_point = os.path.join(iotests.test_dir, 'export.fuse') +Path(fuse_mount_point).touch() + +test_fuse_support(fuse_mount_point) +test_linux_kernel_support() + +class TestMmapShared(iotests.QMPTestCase): + + def setUp(self): + qemu_img('create', '-f', iotests.imgfmt, image, str(image_size)) + qemu_io(image, '-c', f'write -P 23 0 {image_size}') + + self.qsd = QemuStorageDaemon(qmp=True) + + self.qsd.cmd('blockdev-add', { + 'node-name': 'node0', + 'driver': iotests.imgfmt, + 'file': { + 'driver': 'file', + 'filename': image + } + }) + + self.qsd.cmd('block-export-add', { + 'id': 'exp0', + 'type': 'fuse', + 'node-name': 'node0', + 'mountpoint': fuse_mount_point, + 'writable': True, + 'allow-other': 'off' + }) + + def tearDown(self): + self.stop_qsd() + os.remove(image) + os.remove(fuse_mount_point) + + def stop_qsd(self): + if self.qsd: + self.qsd.stop() + self.qsd = None + + def test_mmap_shared(self): + with open(fuse_mount_point, 'r+b') as file: + with mmap.mmap(file.fileno(), image_size, flags=MAP_SHARED) as mm: + buf = bytearray(image_size) + buf[:] = itertools.repeat(23, image_size) + assert mm.read(image_size) == buf + buf[:] = itertools.repeat(42, image_size) + mm.seek(0) + mm.write(buf) + mm.flush() + self.stop_qsd() + qemu_io(image, '-c', f'read -P 42 0 {image_size}') + +if __name__ == '__main__': + iotests.main(supported_fmts=['generic'], + supported_protocols=['file'], + supported_platforms=['linux']) diff --git a/tests/qemu-iotests/tests/fuse-mmap-shared.out b/tests/qemu-iotests/tests/fuse-mmap-shared.out new file mode 100644 index 0000000000..ae1213e6f8 --- /dev/null +++ b/tests/qemu-iotests/tests/fuse-mmap-shared.out @@ -0,0 +1,5 @@ +. +---------------------------------------------------------------------- +Ran 1 tests + +OK -- 2.47.3
