Re: [PATCH V4 2/2] Add test/daxctl-famfs.sh to test famfs mode transitions:

Dave Jiang
2026-02-19T22:03:01Z

On 1/18/26 3:36 PM, John Groves wrote:
> From: John Groves <John@Groves.net>
>
> - devdax <-> famfs mode switches
> - Verify famfs -> system-ram is rejected (must go via devdax)
> - Test JSON output shows correct mode
> - Test error handling for invalid modes
>
> The test is added to the destructive test suite since it
> modifies device modes.
>
> Signed-off-by: John Groves <john@groves.net>
> ---
> test/daxctl-famfs.sh | 253 +++++++++++++++++++++++++++++++++++++++++++
> test/meson.build | 2 +
> 2 files changed, 255 insertions(+)
> create mode 100755 test/daxctl-famfs.sh
>
> diff --git a/test/daxctl-famfs.sh b/test/daxctl-famfs.sh
> new file mode 100755
> index 0000000..12fbfef
> --- /dev/null
> +++ b/test/daxctl-famfs.sh
> @@ -0,0 +1,253 @@
> +#!/bin/bash -Ex
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (C) 2025 Micron Technology, Inc. All rights reserved.
> +#
> +# Test daxctl famfs mode transitions and mode detection
> +
> +rc=77
> +. $(dirname $0)/common
> +
> +trap 'cleanup $LINENO' ERR
> +
> +daxdev=""
> +original_mode=""
> +
> +cleanup()
> +{
> + printf "Error at line %d\n" "$1"
> + # Try to restore to original mode if we know it
> + if [[ $daxdev && $original_mode ]]; then
> + "$DAXCTL" reconfigure-device -f -m "$original_mode" "$daxdev" 2>/dev/null || true
> + fi
> + exit $rc
> +}
> +
> +# Check if fsdev_dax module is available
> +check_fsdev_dax()
> +{
> + if modinfo fsdev_dax &>/dev/null; then
> + return 0
> + fi
> + if grep -qF "fsdev_dax" "/lib/modules/$(uname -r)/modules.builtin" 2>/dev/null; then
> + return 0
> + fi
> + printf "fsdev_dax module not available, skipping\n"
> + exit 77
> +}

Wonder if a common bash function can be created for this and put in "common"

check_kmod_available()?

DJ

> +
> +# Check if kmem module is available (needed for system-ram mode tests)
> +check_kmem()
> +{
> + if modinfo kmem &>/dev/null; then
> + return 0
> + fi
> + if grep -qF "kmem" "/lib/modules/$(uname -r)/modules.builtin" 2>/dev/null; then
> + return 0
> + fi
> + printf "kmem module not available, skipping system-ram tests\n"
> + return 1
> +}
> +
> +# Find an existing dax device to test with
> +find_daxdev()
> +{
> + # Look for any available dax device
> + daxdev=$("$DAXCTL" list | jq -er '.[0].chardev // empty' 2>/dev/null) || true
> +
> + if [[ ! $daxdev ]]; then
> + printf "No dax device found, skipping\n"
> + exit 77
> + fi
> +
> + # Save the original mode so we can restore it
> + original_mode=$("$DAXCTL" list -d "$daxdev" | jq -er '.[].mode')
> +
> + printf "Found dax device: %s (current mode: %s)\n" "$daxdev" "$original_mode"
> +}
> +
> +daxctl_get_mode()
> +{
> + "$DAXCTL" list -d "$1" | jq -er '.[].mode'
> +}
> +
> +# Ensure device is in devdax mode for testing
> +ensure_devdax_mode()
> +{
> + local mode
> + mode=$(daxctl_get_mode "$daxdev")
> +
> + if [[ "$mode" == "devdax" ]]; then
> + return 0
> + fi
> +
> + if [[ "$mode" == "system-ram" ]]; then
> + printf "Device is in system-ram mode, attempting to convert to devdax...\n"
> + "$DAXCTL" reconfigure-device -f -m devdax "$daxdev"
> + elif [[ "$mode" == "famfs" ]]; then
> + printf "Device is in famfs mode, converting to devdax...\n"
> + "$DAXCTL" reconfigure-device -m devdax "$daxdev"
> + else
> + printf "Device is in unknown mode: %s\n" "$mode"
> + return 1
> + fi
> +
> + [[ $(daxctl_get_mode "$daxdev") == "devdax" ]]
> +}
> +
> +#
> +# Test basic mode transitions involving famfs
> +#
> +test_famfs_mode_transitions()
> +{
> + printf "\n=== Testing famfs mode transitions ===\n"
> +
> + # Ensure starting in devdax mode
> + ensure_devdax_mode
> + [[ $(daxctl_get_mode "$daxdev") == "devdax" ]]
> + printf "Initial mode: devdax - OK\n"
> +
> + # Test: devdax -> famfs
> + printf "Testing devdax -> famfs... "
> + "$DAXCTL" reconfigure-device -m famfs "$daxdev"
> + [[ $(daxctl_get_mode "$daxdev") == "famfs" ]]
> + printf "OK\n"
> +
> + # Test: famfs -> famfs (re-enable in same mode)
> + printf "Testing famfs -> famfs (re-enable)... "
> + "$DAXCTL" reconfigure-device -m famfs "$daxdev"
> + [[ $(daxctl_get_mode "$daxdev") == "famfs" ]]
> + printf "OK\n"
> +
> + # Test: famfs -> devdax
> + printf "Testing famfs -> devdax... "
> + "$DAXCTL" reconfigure-device -m devdax "$daxdev"
> + [[ $(daxctl_get_mode "$daxdev") == "devdax" ]]
> + printf "OK\n"
> +
> + # Test: devdax -> devdax (re-enable in same mode)
> + printf "Testing devdax -> devdax (re-enable)... "
> + "$DAXCTL" reconfigure-device -m devdax "$daxdev"
> + [[ $(daxctl_get_mode "$daxdev") == "devdax" ]]
> + printf "OK\n"
> +}
> +
> +#
> +# Test mode transitions with system-ram (requires kmem)
> +#
> +test_system_ram_transitions()
> +{
> + printf "\n=== Testing system-ram transitions with famfs ===\n"
> +
> + # Ensure we start in devdax mode
> + ensure_devdax_mode
> + [[ $(daxctl_get_mode "$daxdev") == "devdax" ]]
> +
> + # Test: devdax -> system-ram
> + printf "Testing devdax -> system-ram... "
> + "$DAXCTL" reconfigure-device -N -m system-ram "$daxdev"
> + [[ $(daxctl_get_mode "$daxdev") == "system-ram" ]]
> + printf "OK\n"
> +
> + # Test: system-ram -> famfs should fail
> + printf "Testing system-ram -> famfs (should fail)... "
> + if "$DAXCTL" reconfigure-device -m famfs "$daxdev" 2>/dev/null; then
> + printf "FAILED - should have been rejected\n"
> + return 1
> + fi
> + printf "OK (correctly rejected)\n"
> +
> + # Test: system-ram -> devdax -> famfs (proper path)
> + printf "Testing system-ram -> devdax -> famfs... "
> + "$DAXCTL" reconfigure-device -f -m devdax "$daxdev"
> + [[ $(daxctl_get_mode "$daxdev") == "devdax" ]]
> + "$DAXCTL" reconfigure-device -m famfs "$daxdev"
> + [[ $(daxctl_get_mode "$daxdev") == "famfs" ]]
> + printf "OK\n"
> +
> + # Restore to devdax for subsequent tests
> + "$DAXCTL" reconfigure-device -m devdax "$daxdev"
> +}
> +
> +#
> +# Test JSON output shows correct mode
> +#
> +test_json_output()
> +{
> + printf "\n=== Testing JSON output for mode field ===\n"
> +
> + # Test devdax mode in JSON
> + ensure_devdax_mode
> + printf "Testing JSON output for devdax mode... "
> + mode=$("$DAXCTL" list -d "$daxdev" | jq -er '.[].mode')
> + [[ "$mode" == "devdax" ]]
> + printf "OK\n"
> +
> + # Test famfs mode in JSON
> + "$DAXCTL" reconfigure-device -m famfs "$daxdev"
> + printf "Testing JSON output for famfs mode... "
> + mode=$("$DAXCTL" list -d "$daxdev" | jq -er '.[].mode')
> + [[ "$mode" == "famfs" ]]
> + printf "OK\n"
> +
> + # Restore to devdax
> + "$DAXCTL" reconfigure-device -m devdax "$daxdev"
> +}
> +
> +#
> +# Test error messages for invalid transitions
> +#
> +test_error_handling()
> +{
> + printf "\n=== Testing error handling ===\n"
> +
> + # Ensure we're in famfs mode
> + "$DAXCTL" reconfigure-device -m famfs "$daxdev"
> +
> + # Test that invalid mode is rejected
> + printf "Testing invalid mode rejection... "
> + if "$DAXCTL" reconfigure-device -m invalidmode "$daxdev" 2>/dev/null; then
> + printf "FAILED - invalid mode should be rejected\n"
> + return 1
> + fi
> + printf "OK (correctly rejected)\n"
> +
> + # Restore to devdax
> + "$DAXCTL" reconfigure-device -m devdax "$daxdev"
> +}
> +
> +#
> +# Main test sequence
> +#
> +main()
> +{
> + check_fsdev_dax
> + find_daxdev
> +
> + rc=1 # From here on, failures are real failures
> +
> + test_famfs_mode_transitions
> + test_json_output
> + test_error_handling
> +
> + # System-ram tests require kmem module
> + if check_kmem; then
> + # Save and disable online policy for system-ram tests
> + saved_policy="$(cat /sys/devices/system/memory/auto_online_blocks)"
> + echo "offline" > /sys/devices/system/memory/auto_online_blocks
> +
> + test_system_ram_transitions
> +
> + # Restore online policy
> + echo "$saved_policy" > /sys/devices/system/memory/auto_online_blocks
> + fi
> +
> + # Restore original mode
> + printf "\nRestoring device to original mode: %s\n" "$original_mode"
> + "$DAXCTL" reconfigure-device -f -m "$original_mode" "$daxdev"
> +
> + printf "\n=== All famfs tests passed ===\n"
> +
> + exit 0
> +}
> +
> +main
> diff --git a/test/meson.build b/test/meson.build
> index 615376e..ad1d393 100644
> --- a/test/meson.build
> +++ b/test/meson.build
> @@ -209,6 +209,7 @@ if get_option('destructive').enabled()
> device_dax_fio = find_program('device-dax-fio.sh')
> daxctl_devices = find_program('daxctl-devices.sh')
> daxctl_create = find_program('daxctl-create.sh')
> + daxctl_famfs = find_program('daxctl-famfs.sh')
> dm = find_program('dm.sh')
> mmap_test = find_program('mmap.sh')
>
> @@ -226,6 +227,7 @@ if get_option('destructive').enabled()
> [ 'device-dax-fio.sh', device_dax_fio, 'dax' ],
> [ 'daxctl-devices.sh', daxctl_devices, 'dax' ],
> [ 'daxctl-create.sh', daxctl_create, 'dax' ],
> + [ 'daxctl-famfs.sh', daxctl_famfs, 'dax' ],
> [ 'dm.sh', dm, 'dax' ],
> [ 'mmap.sh', mmap_test, 'dax' ],
> ]