Re: [PATCH] btrfs: test free space tree mount options

[Eryu Guan <eguan@redhat.com>]

On Thu, Sep 22, 2016 at 12:37:53PM -0700, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> The behavior of different combinations of space_cache mount options
> wasn't well defined, which led to a regression between my initial
> patches adding the free space tree and the 4.5 release. Add a test to
> exercise all of the meaningful permutations of clear_cache,
> nospace_cache, and space_cache.
> 
> This is a regression test for Linux kernel commit "Btrfs: fix mount -o
> clear_cache,space_cache=v2".
> 
> Signed-off-by: Omar Sandoval <osandov@fb.com>

Looks good to me, just one nitpick below.

> ---
> Sorry, resending to the right fstests list...
> 
> The patch to fix this is coming out soon as part of my free space tree
> fixes.
> 
>  tests/btrfs/131     | 150 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/131.out |  20 +++++++
>  tests/btrfs/group   |   1 +
>  3 files changed, 171 insertions(+)
>  create mode 100755 tests/btrfs/131
>  create mode 100644 tests/btrfs/131.out
> 
> diff --git a/tests/btrfs/131 b/tests/btrfs/131
> new file mode 100755
> index 0000000..cc75153
> --- /dev/null
> +++ b/tests/btrfs/131
> @@ -0,0 +1,150 @@
> +#! /bin/bash
> +# FS QA Test 131
> +#
> +# Test free space tree mount options.
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2016 Facebook.  All Rights Reserved.
> +#
> +# This program is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU General Public License as
> +# published by the Free Software Foundation.
> +#
> +# This program is distributed in the hope that it would be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program; if not, write the Free Software Foundation,
> +# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> +#-----------------------------------------------------------------------
> +#
> +
> +seq=`basename $0`
> +seqres=$RESULT_DIR/$seq
> +echo "QA output created by $seq"
> +
> +here=`pwd`
> +tmp=/tmp/$$
> +status=1	# failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> +	cd /
> +	rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +
> +_supported_fs btrfs
> +_supported_os Linux
> +_require_scratch
> +_require_btrfs inspect-internal
> +
> +_mkfs_v1() {

We usually name local functions without the leading "_", it's used for
common helpers. And placing "{" in a separate line is preferred for
functions.

I can fix them at commit time if there're no more comments from others.

Thanks,
Eryu

> +	_scratch_mkfs >/dev/null 2>&1
> +	# Future proof against btrfs-progs making space_cache=v2 filesystems by
> +	# default.
> +	_scratch_mount -o clear_cache,space_cache=v1
> +	_scratch_unmount
> +}
> +
> +_mkfs_v2() {
> +	_scratch_mkfs >/dev/null 2>&1
> +	_scratch_mount -o space_cache=v2
> +	_scratch_unmount
> +}
> +
> +_check_fst_compat() {
> +	compat_ro="$($BTRFS_UTIL_PROG inspect-internal dump-super "$SCRATCH_DEV" | \
> +		     sed -rn 's/^compat_ro_flags\s+(.*)$/\1/p')"
> +	if ((compat_ro & 0x1)); then
> +		echo "free space tree is enabled"
> +	else
> +		echo "free space tree is disabled"
> +	fi
> +}
> +
> +# Mount options might interfere.
> +export MOUNT_OPTIONS=""
> +
> +# When the free space tree is not enabled:
> +# -o space_cache=v1: keep using the old free space cache
> +# -o space_cache=v2: enable the free space tree
> +# -o clear_cache,space_cache=v2: clear the free space cache and enable the free space tree
> +# We don't check the no options case or plain space_cache as that will change
> +# in the future to turn on space_cache=v2.
> +
> +_mkfs_v1
> +echo "Using free space cache"
> +_scratch_mount -o space_cache=v1
> +_check_fst_compat
> +_scratch_unmount
> +
> +_mkfs_v1
> +echo "Enabling free space tree"
> +_scratch_mount -o space_cache=v2
> +_check_fst_compat
> +_scratch_unmount
> +
> +_mkfs_v1
> +echo "Disabling free space cache and enabling free space tree"
> +_scratch_mount -o clear_cache,space_cache=v2
> +_check_fst_compat
> +_scratch_unmount
> +
> +# When the free space tree is enabled:
> +# -o nospace_cache, -o space_cache=v1: error
> +# no options, -o space_cache=v2: keep using the free space tree
> +# -o clear_cache, -o clear_cache,space_cache=v2: clear and recreate the free space tree
> +# -o clear_cache,nospace_cache: clear the free space tree
> +# -o clear_cache,space_cache=v1: clear the free space tree, enable the free space cache
> +
> +_mkfs_v2
> +echo "Trying to mount without free space tree"
> +_scratch_mount -o nospace_cache >/dev/null 2>&1 || echo "mount failed"
> +_scratch_mount -o space_cache=v1 >/dev/null 2>&1 || echo "mount failed"
> +
> +_mkfs_v2
> +echo "Mounting existing free space tree"
> +_scratch_mount
> +_check_fst_compat
> +_scratch_unmount
> +_scratch_mount -o space_cache=v2
> +_check_fst_compat
> +_scratch_unmount
> +
> +_mkfs_v2
> +echo "Recreating free space tree"
> +_scratch_mount -o clear_cache,space_cache=v2
> +_check_fst_compat
> +_scratch_unmount
> +_mkfs_v2
> +_scratch_mount -o clear_cache
> +_check_fst_compat
> +_scratch_unmount
> +
> +_mkfs_v2
> +echo "Disabling free space tree"
> +_scratch_mount -o clear_cache,nospace_cache
> +_check_fst_compat
> +_scratch_unmount
> +
> +_mkfs_v2
> +echo "Reverting to free space cache"
> +_scratch_mount -o clear_cache,space_cache=v1
> +_check_fst_compat
> +_scratch_unmount
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/btrfs/131.out b/tests/btrfs/131.out
> new file mode 100644
> index 0000000..aaa4a70
> --- /dev/null
> +++ b/tests/btrfs/131.out
> @@ -0,0 +1,20 @@
> +QA output created by 131
> +Using free space cache
> +free space tree is disabled
> +Enabling free space tree
> +free space tree is enabled
> +Disabling free space cache and enabling free space tree
> +free space tree is enabled
> +Trying to mount without free space tree
> +mount failed
> +mount failed
> +Mounting existing free space tree
> +free space tree is enabled
> +free space tree is enabled
> +Recreating free space tree
> +free space tree is enabled
> +free space tree is enabled
> +Disabling free space tree
> +free space tree is disabled
> +Reverting to free space cache
> +free space tree is disabled
> diff --git a/tests/btrfs/group b/tests/btrfs/group
> index f3a7a4f..c090604 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -133,3 +133,4 @@
>  128 auto quick send
>  129 auto quick send
>  130 auto clone send
> +131 auto quick
> -- 
> 2.10.0
> 
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