On Mon, Nov 20, 2023 at 03:03:27PM +0800, Baokun Li wrote:
> Append writes to a file approaching 16T and observe if a kernel crash is
> caused by ext4_lblk_t overflow triggering BUG_ON at ext4_mb_new_inode_pa().
> This is a regression test for commit bc056e7163ac ("ext4: fix BUG in
> ext4_mb_new_inode_pa() due to overflow")
>
> Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
> ---
> V1->V2:
> Changes to make the use case more generic, not just for testing
> ext4.(ext4 and xfs have been tested)
Thanks for this change,
>
> tests/generic/737 | 55 +++++++++++++++++++++++++++++++++++++++++++
> tests/generic/737.out | 2 ++
> 2 files changed, 57 insertions(+)
> create mode 100755 tests/generic/737
> create mode 100644 tests/generic/737.out
>
> diff --git a/tests/generic/737 b/tests/generic/737
> new file mode 100755
> index 00000000..a65c448b
> --- /dev/null
> +++ b/tests/generic/737
> @@ -0,0 +1,55 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2023 HUAWEI. All Rights Reserved.
> +#
> +# FS QA Test No. 737
> +#
> +# Append writes to a file approaching 16T and observe if a kernel crash is
> +# caused by ext4_lblk_t overflow triggering BUG_ON at ext4_mb_new_inode_pa().
> +# This is a regression test for commit
> +# bc056e7163ac ("ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow")
> +#
> +#set -x
Useless comment "set -x"
> +. ./common/preamble
> +. ./common/populate
> +_begin_fstest auto quick insert prealloc
> +
> +# real QA test starts here
> +_fixed_by_kernel_commit bc056e7163ac \
> + "ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow"
[[ "$FSTYP" =~ ext* ]] && ....
> +
> +_require_xfs_io_command "falloc"
> +_require_xfs_io_command "finsert"
> +
> +# Initalize a 4k 100M fs
It might not be 4k block size, so this comment is useless. Or you can say
better to use "4k" block size to tigger the bug:)
> +dev_size=$((100 * 1024 * 1024))
> +_scratch_mkfs_sized $dev_size >>$seqres.full 2>&1 || _fail "mkfs failed"
> +
> +_scratch_mount
> +blksz="$(_get_block_size ${SCRATCH_MNT})"
> +_require_odirect $blksz
I think the _require_odirect can be move up, before the mkfs calling.
> +
> +# Reserve 1M space
> +$XFS_IO_PROG -f -c "falloc 0 1M" "${SCRATCH_MNT}/tmp" >> $seqres.full
> +
> +# Create a file (~16T) with logical block numbers close to overflow
> +$XFS_IO_PROG -f -c "falloc 0 10M" "${SCRATCH_MNT}/file" >> $seqres.full
> +insert_size=$((blksz * 4096 - 10 - 3))
> +$XFS_IO_PROG -f -c "finsert 1M ${insert_size}M" "${SCRATCH_MNT}/file" >> $seqres.full
> +
> +# Filling up the free space ensures that the pre-allocated space is the reserved space.
> +nr_free=$(stat -f -c '%f' ${SCRATCH_MNT})
> +_fill_fs $((nr_free * blksz)) ${SCRATCH_MNT}/fill $blksz 0 >> $seqres.full 2>&1
> +sync
> +
> +# Remove reserved space to gain free space for allocation
> +rm -f ${SCRATCH_MNT}/tmp
> +
> +# Trying to allocate two blocks triggers BUG_ON.
> +$XFS_IO_PROG -c "open -ad ${SCRATCH_MNT}/file" -c "pwrite -S 0xff 0 8192" >> $seqres.full
Shouldn't the 8192 be "$((2 * blksz))", if the comment says "two blocks" ?
I tried 1024 blocksize, really can't reproduce this bug, do you know why? Maybe
related with the falloc/finsert size?
Anyway, it covers this bug on default block size of ext4, and can be a generic
test on other conditions.
Thanks,
Zorro
> +
> +echo "Silence is golden"
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/generic/737.out b/tests/generic/737.out
> new file mode 100644
> index 00000000..67b83d78
> --- /dev/null
> +++ b/tests/generic/737.out
> @@ -0,0 +1,2 @@
> +QA output created by 737
> +Silence is golden
> --
> 2.31.1
>
