Re: [PATCH v2] generic: add test for XFS forkoff miscalcution on 32-bit platform

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Mon, Nov 23, 2020 at 04:20:47PM +0800, Gao Xiang wrote:
> There is a regression that recent XFS_LITINO(mp) update causes
> xfs_attr_shortform_bytesfit() returns maxforkoff rather than 0.
> 
> Therefore, one result is
>   "ASSERT(new_size <= XFS_IFORK_SIZE(ip, whichfork));"
> 
> Add a regression test in fstests generic to look after that since
> the testcase itself isn't xfs-specific.
> 
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---
> changes since v1:
>  - update commit id since the fix has been upstreamed (Eryu);
>  - switch to use scratch_mkfs instead since fixed inode size is
>    prefered to keep XFS_LITINO value can trigger the issue for
>    v4 (412) and v5 (336); and no need to use TEST_DIR
>    "rm localfile" way
>  - refine some inlined comments.
> 
>  tests/generic/618     | 67 +++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/618.out |  4 +++
>  tests/generic/group   |  1 +
>  3 files changed, 72 insertions(+)
>  create mode 100755 tests/generic/618
>  create mode 100644 tests/generic/618.out
> 
> diff --git a/tests/generic/618 b/tests/generic/618
> new file mode 100755
> index 00000000..bdaa3874
> --- /dev/null
> +++ b/tests/generic/618
> @@ -0,0 +1,67 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2020 Red Hat, Inc. All Rights Reserved.
> +#
> +# FS QA Test 618
> +#
> +# Verify that forkoff can be returned as 0 properly if it isn't
> +# able to fit inline for XFS.
> +# However, this test is fs-neutral and can be done quickly so
> +# leave it in generic
> +# This test verifies the problem fixed in kernel with commit
> +# ada49d64fb35 ("xfs: fix forkoff miscalculation related to XFS_LITINO(mp)")
> +
> +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
> +. ./common/attr
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +
> +_supported_fs generic
> +_require_scratch
> +_require_attrs user

Does this require

_require_no_xfs_bug_on_assert ?

> +
> +# Use fixed inode size 512, so both v4 and v5 can be tested,
> +# and also make sure the issue can be triggered if the default
> +# inode size is changed later.
> +[ $FSTYP = "xfs" ] && MKFS_OPTIONS="$MKFS_OPTIONS -i size=512"
> +_scratch_mkfs > $seqres.full 2>&1
> +_scratch_mount
> +
> +localfile="${SCRATCH_MNT}/testfile"
> +touch $localfile
> +
> +# value cannot exceed XFS_ATTR_SF_ENTSIZE_MAX (256) or it will turn into
> +# leaf form directly; the following combination can trigger the issue for
> +# both v4 (XFS_LITINO = 412) & v5 (XFS_LITINO = 336) fses.
> +"${SETFATTR_PROG}" -n user.0 -v "`seq 0 80`" "${localfile}"
> +"${SETFATTR_PROG}" -n user.1 -v "`seq 0 80`" "${localfile}"

It's probably worth mentioning that the second setattr causes an integer
underflow that is incorrectly typecast, leading to the assert
triggering.  Otherwise this seems reasonable to me.

--D

> +
> +# Make sure that changes are written to disk
> +_scratch_cycle_mount
> +
> +# getfattr won't succeed with the expected result if fails
> +_getfattr --absolute-names -ebase64 -d $localfile | tail -n +2 | sort
> +
> +_scratch_unmount
> +status=0
> +exit
> diff --git a/tests/generic/618.out b/tests/generic/618.out
> new file mode 100644
> index 00000000..848fdc58
> --- /dev/null
> +++ b/tests/generic/618.out
> @@ -0,0 +1,4 @@
> +QA output created by 618
> +
> +user.0=0sMAoxCjIKMwo0CjUKNgo3CjgKOQoxMAoxMQoxMgoxMwoxNAoxNQoxNgoxNwoxOAoxOQoyMAoyMQoyMgoyMwoyNAoyNQoyNgoyNwoyOAoyOQozMAozMQozMgozMwozNAozNQozNgozNwozOAozOQo0MAo0MQo0Mgo0Mwo0NAo0NQo0Ngo0Nwo0OAo0OQo1MAo1MQo1Mgo1Mwo1NAo1NQo1Ngo1Nwo1OAo1OQo2MAo2MQo2Mgo2Mwo2NAo2NQo2Ngo2Nwo2OAo2OQo3MAo3MQo3Mgo3Mwo3NAo3NQo3Ngo3Nwo3OAo3OQo4MA==
> +user.1=0sMAoxCjIKMwo0CjUKNgo3CjgKOQoxMAoxMQoxMgoxMwoxNAoxNQoxNgoxNwoxOAoxOQoyMAoyMQoyMgoyMwoyNAoyNQoyNgoyNwoyOAoyOQozMAozMQozMgozMwozNAozNQozNgozNwozOAozOQo0MAo0MQo0Mgo0Mwo0NAo0NQo0Ngo0Nwo0OAo0OQo1MAo1MQo1Mgo1Mwo1NAo1NQo1Ngo1Nwo1OAo1OQo2MAo2MQo2Mgo2Mwo2NAo2NQo2Ngo2Nwo2OAo2OQo3MAo3MQo3Mgo3Mwo3NAo3NQo3Ngo3Nwo3OAo3OQo4MA==
> diff --git a/tests/generic/group b/tests/generic/group
> index 94e860b8..eca9d619 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -620,3 +620,4 @@
>  615 auto rw
>  616 auto rw io_uring stress
>  617 auto rw io_uring stress
> +618 auto quick attr
> -- 
> 2.18.4
>