Re: [PATCH v2] fstests: btrfs/246: add test case to make sure btrfs can create compressed inline extent

[Eryu Guan <guaneryu@gmail.com>]

On Thu, Aug 26, 2021 at 01:34:32PM +0800, Qu Wenruo wrote:
> Btrfs has the ability to inline small file extents into its metadata,
> and such inlined extents can be further compressed if needed.
> 
> The new test case is for a regression caused by commit f2165627319f
> ("btrfs: compression: don't try to compress if we don't have enough
> pages").
> 
> That commit prevents btrfs from creating compressed inline extents, even
> "-o compress,max_inline=2048" is specified, only uncompressed inline
> extents can be created.
> 
> The test case will make sure that the content of the small file is
> consistent between cycle mount, then use "btrfs inspect dump-tree" to
> verify the created extent is both inlined and compressed.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Is there a proposed fix available that could be referenced in the commit
log?

> ---
> Changelog:
> v2:
> - Also output the sha256sum to make sure the content is consistent
> ---
>  tests/btrfs/246     | 53 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/246.out |  5 +++++
>  2 files changed, 58 insertions(+)
>  create mode 100755 tests/btrfs/246
>  create mode 100644 tests/btrfs/246.out
> 
> diff --git a/tests/btrfs/246 b/tests/btrfs/246
> new file mode 100755
> index 00000000..e0d8016f
> --- /dev/null
> +++ b/tests/btrfs/246
> @@ -0,0 +1,53 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2021 SUSE Linux Products GmbH.  All Rights Reserved.
> +#
> +# FS QA Test 246
> +#
> +# Make sure btrfs can create compressed inline extents
> +#
> +. ./common/preamble
> +_begin_fstest auto quick compress
> +
> +# Override the default cleanup function.
> +_cleanup()
> +{
> +	cd /
> +	rm -r -f $tmp.*
> +}
> +
> +# Import common functions.
> +. ./common/filter
> +# For __populate_find_inode()
> +. ./common/populate

This function starts with double underscore, I take it as a 'private'
function in common/populate. But all it does is returning the inode
number of the given file, I think we could just open-code it in this
test as

ino=$(stat -c %i $SCRATCH_MNT/foobar)

Otherwise test looks fine to me.

Thanks,
Eryu

> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs btrfs
> +_require_scratch
> +
> +_scratch_mkfs > /dev/null
> +_scratch_mount -o compress,max_inline=2048
> +
> +# This should create compressed inline extent
> +$XFS_IO_PROG -f -c "pwrite 0 2048" $SCRATCH_MNT/foobar > /dev/null
> +ino=$(__populate_find_inode $SCRATCH_MNT/foobar)
> +echo "sha256sum before mount cycle"
> +sha256sum $SCRATCH_MNT/foobar | _filter_scratch
> +_scratch_cycle_mount
> +echo "sha256sum after mount cycle"
> +sha256sum $SCRATCH_MNT/foobar | _filter_scratch
> +_scratch_unmount
> +
> +$BTRFS_UTIL_PROG inspect dump-tree -t 5 $SCRATCH_DEV | \
> +	grep "($ino EXTENT_DATA 0" -A2 > $tmp.dump-tree
> +echo "dump tree result for ino $ino:" >> $seqres.full
> +cat $tmp.dump-tree >> $seqres.full
> +
> +grep -q "inline extent" $tmp.dump-tree || echo "no inline extent found"
> +grep -q "compression 1" $tmp.dump-tree || echo "no compressed extent found"
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/btrfs/246.out b/tests/btrfs/246.out
> new file mode 100644
> index 00000000..3908cc50
> --- /dev/null
> +++ b/tests/btrfs/246.out
> @@ -0,0 +1,5 @@
> +QA output created by 246
> +sha256sum before mount cycle
> +0ca3bfdeda1ef5036bfa5dad078a9f15724e79cf296bd4388cf786bfaf4195d0  SCRATCH_MNT/foobar
> +sha256sum after mount cycle
> +0ca3bfdeda1ef5036bfa5dad078a9f15724e79cf296bd4388cf786bfaf4195d0  SCRATCH_MNT/foobar
> -- 
> 2.31.1