Re: [PATCH v8 09/13] fstests: verify libblkid resolution of duplicate UUIDs

[Anand Suveer Jain <asj@kernel.org>]

On 2/9/26 03:12, Zorro Lang wrote:
> On Sat, Jul 25, 2026 at 03:39:06PM +0800, Anand Jain wrote:
>> Verify how findmnt, df (libblkid) resolve device paths when multiple
> 
> I didn't find the `df` test part in this test case.
> 

Hm, I think `df` was too basic and didn't add any real value, so I've
removed it. I'll update the changelog accordingly.


>> block devices share the same FSUUID.
>>
>> Signed-off-by: Anand Jain <asj@kernel.org>
>> ---
>>  tests/generic/803     | 72 +++++++++++++++++++++++++++++++++++++++++++
>>  tests/generic/803.out |  6 ++++
>>  2 files changed, 78 insertions(+)
>>  create mode 100644 tests/generic/803
>>  create mode 100644 tests/generic/803.out
>>
>> diff --git a/tests/generic/803 b/tests/generic/803
>> new file mode 100644
>> index 000000000000..77901592366c
>> --- /dev/null
>> +++ b/tests/generic/803
>> @@ -0,0 +1,72 @@
>> +#! /bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2026 Anand Jain <asj@kernel.org>.  All Rights Reserved.
>> +#
>> +# FS QA Test 803
>> +# Check if the mountinfo based findmnt would resolve to the common uuid
>> +# as per the blkid (libblkid based).
>> +
>> +. ./common/preamble
>> +. ./common/filter
>> +
>> +_begin_fstest auto quick mount clone
>> +
>> +_require_test
>> +_require_block_device $TEST_DEV
>> +_require_loop
>> +
>> +_cleanup()
>> +{
>> +	cd /
>> +	rm -r -f $tmp.*
>> +	umount $mnt1 $mnt2 2>/dev/null
>> +	_loop_image_destroy "${devs[@]}" 2> /dev/null
>> +}
>> +
>> +# Normalize pool devices and mount points names
>> +filter_pool()
>> +{
>> +	sed -e "s|${devs[0]}|DEV1|g" -e "s|${mnt1}|MNT1|g" \
>> +	    -e "s|${devs[1]}|DEV2|g" -e "s|${mnt2}|MNT2|g" | _filter_spaces
>> +}
>> +
>> +# Setup base loop device and its clone
>> +devs=()
>> +_loop_image_create_clone devs
>> +mkdir -p $TEST_DIR/$seq
>> +mnt1=$TEST_DIR/$seq/mnt1
>> +mnt2=$TEST_DIR/$seq/mnt2
>> +mkdir -p $mnt1
>> +mkdir -p $mnt2
>> +
>> +# Get the uuid from the source device
>> +fsuuid=$(blkid -s UUID -o value ${devs[0]})
>> +
>> +# Mount both identical UUID filesystems simultaneously
>> +_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[0]} $mnt1 || \
>> +						_fail "Failed to mount dev1"
>> +_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[1]} $mnt2 || \
>> +						_fail "Failed to mount dev2"
>> +
>> +findmnt -o SOURCE,TARGET,UUID "${devs[0]}" | tail -n +2 | \
>> +				sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
> 

> findmnt -n (or --noheadings) can be used here (and below) to avoid piping to
> `tail -n +2`.

applied.

> 
>> +findmnt -o SOURCE,TARGET,UUID "${devs[1]}" | tail -n +2 | \
>> +				sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
> 
> Same here

applied

> 
>> +
>> +# Btrfs assigned a random uuid for the clone fs before the fix.
>> +# Cycle mounts and reverse the initialization (source and clone fs) order.
>> +echo "**** mount cycle ****"
>> +_unmount $mnt1
>> +_unmount $mnt2
>> +_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[1]} $mnt2 || \
>> +						_fail "Failed to mount dev2"
>> +_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[0]} $mnt1 || \
>> +						_fail "Failed to mount dev1"
>> +
>> +findmnt -o SOURCE,TARGET,UUID "${devs[0]}" | tail -n +2 | \
>> +				sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
> 
> Same here
applied

> 
>> +findmnt -o SOURCE,TARGET,UUID "${devs[1]}" | tail -n +2 | \
>> +				sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
> 
> Same here
applied

> 
>> +	
>> +status=0
>> +exit
> 
> _exit 0
applied


Thanks.>
>> diff --git a/tests/generic/803.out b/tests/generic/803.out
>> new file mode 100644
>> index 000000000000..3a130c662430
>> --- /dev/null
>> +++ b/tests/generic/803.out
>> @@ -0,0 +1,6 @@
>> +QA output created by 803
>> +DEV1 MNT1 FSUUID
>> +DEV2 MNT2 FSUUID
>> +**** mount cycle ****
>> +DEV1 MNT1 FSUUID
>> +DEV2 MNT2 FSUUID
>> -- 
>> 2.43.0
>>