Re: [PATCH v2] btrfs: Add test for the single-dev feature

[Josef Bacik <josef@toxicpanda.com>]

On Tue, Sep 05, 2023 at 05:06:56PM -0300, Guilherme G. Piccoli wrote:
> The SINGLE_DEV btrfs feature allows to mount the same filesystem
> multiple times, at the same time. This is the fstests counter-part,
> which checks both mkfs/btrfstune (by mounting the FS twice), and
> also unsupported scenarios, like device replace / remove.
> 
> Suggested-by: Anand Jain <anand.jain@oracle.com>
> Suggested-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
> ---
> 
> V2:
> - Rebased against v2023.09.03 / changed test number to 301;
> 
> - Implemented the great suggestions from Anand, which definitely
> made the test more clear and concise;
> 
> -Cc'ing linux-btrfs as well.
> 
> Thanks in advance for reviews / comments!
> Cheers,
> 
> Guilherme
> 
> 
>  tests/btrfs/301     | 94 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/301.out |  5 +++
>  2 files changed, 99 insertions(+)
>  create mode 100755 tests/btrfs/301
>  create mode 100644 tests/btrfs/301.out
> 
> diff --git a/tests/btrfs/301 b/tests/btrfs/301
> new file mode 100755
> index 000000000000..5f8abdbe157a
> --- /dev/null
> +++ b/tests/btrfs/301
> @@ -0,0 +1,94 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2023 Guilherme G. Piccoli (Igalia S.L.).  All Rights Reserved.
> +#
> +# FS QA Test 301
> +#
> +# Test for the btrfs single-dev feature - both mkfs and btrfstune are
> +# validated, as well as explicitly unsupported commands, like device
> +# removal / replacement.
> +#
> +. ./common/preamble
> +_begin_fstest auto mkfs quick
> +. ./common/filter

Normally we group all the require'd stuff together
> +_supported_fs btrfs
> +
> +_require_btrfs_mkfs_feature single-dev
> +_require_btrfs_fs_feature single_dev
> +
> +_require_scratch_dev_pool 2
> +_scratch_dev_pool_get 1
> +_spare_dev_get
> +
> +_require_command "$BTRFS_TUNE_PROG" btrfstune
> +_require_command "$WIPEFS_PROG" wipefs
> +
> +# Helper to mount a btrfs fs
> +# Arg 1: device
> +# Arg 2: mount point
> +mount_btrfs()
> +{
> +	$MOUNT_PROG -t btrfs $1 $2
> +	[ $? -ne 0 ] && _fail "mounting $1 on $2 failed"
> +}
> +
> +SPARE_MNT="${TEST_DIR}/${seq}/spare_mnt"
> +mkdir -p $SPARE_MNT
> +
> +
> +# Part 1
> +# First test involves a mkfs with single-dev feature enabled.
> +# If it succeeds and mounting that FS *twice* also succeeds,
> +# we're good and continue.
> +$WIPEFS_PROG -a $SCRATCH_DEV >> $seqres.full 2>&1
> +$WIPEFS_PROG -a $SPARE_DEV >> $seqres.full 2>&1
> +
> +_scratch_mkfs "-b 300M -O single-dev" >> $seqres.full 2>&1
> +dd if=$SCRATCH_DEV of=$SPARE_DEV bs=300M count=1 conv=fsync >> $seqres.full 2>&1
> +
> +mount_btrfs $SCRATCH_DEV $SCRATCH_MNT

You can just use _scratch_mount here, since you want to handle failures just

_scratch_mount || _fail "failed to mount scratch mount"

> +mount_btrfs $SPARE_DEV $SPARE_MNT

Instead use _mount here

_mount $SPARE_DEV $SPARE_MNT || _fail "failed to mount spare dev"

> +
> +$UMOUNT_PROG $SPARE_MNT
> +$UMOUNT_PROG $SCRATCH_MNT

_scratch_unmount

> +
> +
> +# Part 2
> +# Second test is similar to the first with the difference we
> +# run mkfs with no single-dev mention, and make use of btrfstune
> +# to set such feature.
> +$WIPEFS_PROG -a $SCRATCH_DEV >> $seqres.full 2>&1
> +$WIPEFS_PROG -a $SPARE_DEV >> $seqres.full 2>&1
> +
> +_scratch_mkfs "-b 300M" >> $seqres.full 2>&1
> +$BTRFS_TUNE_PROG --convert-to-single-device $SCRATCH_DEV
> +dd if=$SCRATCH_DEV of=$SPARE_DEV bs=300M count=1 conv=fsync >> $seqres.full 2>&1
> +
> +mount_btrfs $SCRATCH_DEV $SCRATCH_MNT

_scratch_mount

> +mount_btrfs $SPARE_DEV $SPARE_MNT

_mount

> +
> +$UMOUNT_PROG $SPARE_MNT
> +$UMOUNT_PROG $SCRATCH_MNT

_scratch_unmount

> +
> +
> +# Part 3
> +# Final part attempts to run some single-dev unsupported commands,
> +# like device replace/remove - it they fail, test succeeds!
> +mount_btrfs $SCRATCH_DEV $SCRATCH_MNT

_scratch_mount

> +
> +$BTRFS_UTIL_PROG device replace start $SCRATCH_DEV $SCRATCH_DEV $SCRATCH_MNT 2>&1 \
> +	| _filter_scratch
> +
> +$BTRFS_UTIL_PROG device remove $SCRATCH_DEV $SCRATCH_MNT 2>&1 \
> +	| _filter_scratch
> +
> +$UMOUNT_PROG $SCRATCH_MNT

_scratch_unmount

> +
> +_spare_dev_put
> +_scratch_dev_pool_put 1
> +
> +# success, all done
> +status=0
> +echo "Finished"

Don't need this bit.  Thanks,

Josef