linux-kernel - Re: [PATCH v3 13/13] ext4/064: Add atomic write tests for journal credit calculation

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Message-ID: <20250729193651.GS2672039@frogsfrogsfrogs>
Date: Tue, 29 Jul 2025 12:36:51 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: Ojaswin Mujoo <ojaswin@...ux.ibm.com>
Cc: Zorro Lang <zlang@...hat.com>, fstests@...r.kernel.org,
	Ritesh Harjani <ritesh.list@...il.com>, john.g.garry@...cle.com,
	tytso@....edu, linux-xfs@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-ext4@...r.kernel.org
Subject: Re: [PATCH v3 13/13] ext4/064: Add atomic write tests for journal
 credit calculation

On Sat, Jul 12, 2025 at 07:42:55PM +0530, Ojaswin Mujoo wrote:
> Test atomic writes with journal credit calculation. We take 2 cases
> here:
> 
> 1. Atomic writes on single mapping causing tree to collapse into
>    the inode
> 2. Atomic writes on mixed mapping causing tree to collapse into the
>    inode
> 
> This test is inspired by ext4/034.
> 
> Suggested-by: Ritesh Harjani (IBM) <ritesh.list@...il.com>
> Signed-off-by: Ojaswin Mujoo <ojaswin@...ux.ibm.com>
> ---
>  tests/ext4/064     | 75 ++++++++++++++++++++++++++++++++++++++++++++++
>  tests/ext4/064.out |  2 ++
>  2 files changed, 77 insertions(+)
>  create mode 100755 tests/ext4/064
>  create mode 100644 tests/ext4/064.out
> 
> diff --git a/tests/ext4/064 b/tests/ext4/064
> new file mode 100755
> index 00000000..ec31f983
> --- /dev/null
> +++ b/tests/ext4/064
> @@ -0,0 +1,75 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2025 IBM Corporation. All Rights Reserved.
> +#
> +# FS QA Test 034
> +#
> +# Test proper credit reservation is done when performing
> +# tree collapse during an aotmic write based allocation
> +#
> +. ./common/preamble
> +. ./common/atomicwrites
> +_begin_fstest auto quick quota fiemap prealloc atomicwrites
> +
> +# Import common functions.
> +
> +
> +# Modify as appropriate.
> +_exclude_fs ext2
> +_exclude_fs ext3
> +_require_xfs_io_command "falloc"
> +_require_xfs_io_command "fiemap"
> +_require_xfs_io_command "syncfs"
> +_require_scratch_write_atomic_multi_fsblock
> +_require_atomic_write_test_commands

_require_metadata_journaling $SCRATCH_DEV ?

> +
> +echo "----- Testing with atomic write on non-mixed mapping -----" >> $seqres.full
> +
> +echo "Format and mount" >> $seqres.full
> +_scratch_mkfs  > $seqres.full 2>&1
> +_scratch_mount > $seqres.full 2>&1
> +
> +echo "Create the original file" >> $seqres.full
> +touch $SCRATCH_MNT/foobar >> $seqres.full
> +
> +echo "Create 2 level extent tree (btree) for foobar with a unwritten extent" >> $seqres.full
> +$XFS_IO_PROG -f -c "pwrite 0 4k" -c "falloc 4k 4k" -c "pwrite 8k 4k" \
> +	     -c "pwrite 20k 4k"  -c "pwrite 28k 4k" -c "pwrite 36k 4k" \
> +	     -c "fsync" $SCRATCH_MNT/foobar >> $seqres.full

What happens if the block size isn't 4k?

--D

> +
> +$XFS_IO_PROG -c "fiemap -v" $SCRATCH_MNT/foobar >> $seqres.full
> +
> +echo "Convert unwritten extent to written and collapse extent tree to inode" >> $seqres.full
> +$XFS_IO_PROG -dc "pwrite -A -V1 4k 4k" $SCRATCH_MNT/foobar >> $seqres.full
> +
> +echo "Create a new file and do fsync to force a jbd2 commit" >> $seqres.full
> +$XFS_IO_PROG -f -c "pwrite 0 4k" -c "fsync" $SCRATCH_MNT/dummy >> $seqres.full
> +
> +echo "sync $SCRATCH_MNT to writeback" >> $seqres.full
> +$XFS_IO_PROG -c "syncfs" $SCRATCH_MNT >> $seqres.full
> +
> +echo "----- Testing with atomi write on mixed mapping -----" >> $seqres.full
> +
> +echo "Create the original file" >> $seqres.full
> +touch $SCRATCH_MNT/foobar2 >> $seqres.full
> +
> +echo "Create 2 level extent tree (btree) for foobar2 with a unwritten extent" >> $seqres.full
> +$XFS_IO_PROG -f -c "pwrite 0 4k" -c "falloc 4k 4k" -c "pwrite 8k 4k" \
> +	     -c "pwrite 20k 4k"  -c "pwrite 28k 4k" -c "pwrite 36k 4k" \
> +	     -c "fsync" $SCRATCH_MNT/foobar2 >> $seqres.full
> +
> +$XFS_IO_PROG -c "fiemap -v" $SCRATCH_MNT/foobar2 >> $seqres.full
> +
> +echo "Convert unwritten extent to written and collapse extent tree to inode" >> $seqres.full
> +$XFS_IO_PROG -dc "pwrite -A -V1 0k 12k" $SCRATCH_MNT/foobar2 >> $seqres.full
> +
> +echo "Create a new file and do fsync to force a jbd2 commit" >> $seqres.full
> +$XFS_IO_PROG -f -c "pwrite 0 4k" -c "fsync" $SCRATCH_MNT/dummy2 >> $seqres.full
> +
> +echo "sync $SCRATCH_MNT to writeback" >> $seqres.full
> +$XFS_IO_PROG -c "syncfs" $SCRATCH_MNT >> $seqres.full
> +
> +# success, all done
> +echo "Silence is golden"
> +status=0
> +exit
> diff --git a/tests/ext4/064.out b/tests/ext4/064.out
> new file mode 100644
> index 00000000..d9076546
> --- /dev/null
> +++ b/tests/ext4/064.out
> @@ -0,0 +1,2 @@
> +QA output created by 064
> +Silence is golden
> -- 
> 2.49.0
> 
>