Re: [PATCH V2] overlay: Test constant d_ino feature

[Amir Goldstein <amir73il@gmail.com>]

On Thu, Aug 31, 2017 at 9:35 AM, Chandan Rajendra
<chandan@linux.vnet.ibm.com> wrote:
> This commit adds a test to verify constant d_ino feature. The following
> scenarios are checked,
> - Parent's (i.e. "..") d_ino must always be calculated because a pure
>   dir can be residing inside a merged dir.
> - d_ino for "." must always be calculated because the present directory
>   can have a copy-up origin.
> - Verify d_ino values corresponding to "." and ".." entries of a pure
>   lower dir.
> - Verify d_ino of ".." entry of a merged dir.
> - Verify pure lower residing in dir which has another lower layer pure
>   lower residing in dir which has another lower layer.
>
> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
> ---
> Changelog:
> v1->v2:
> 1. Removed tests copied over from overlay/017.
> 2. Removed src/t_dir_ino.c.
> 3. Add code for testing,
>    - d_ino of . and .. entries of pure_lower_dir.
>    - d_ino of .. entry of merged_dir.
>    - Verify pure lower residing in dir which has another lower layer.
>    Thanks to Amir for suggesting these tests.

Nice work!
See more comments below.

>
>  tests/overlay/037     | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/overlay/037.out |   2 +
>  tests/overlay/group   |   1 +
>  3 files changed, 147 insertions(+)
>  create mode 100755 tests/overlay/037
>  create mode 100644 tests/overlay/037.out
>
> diff --git a/tests/overlay/037 b/tests/overlay/037
> new file mode 100755
> index 0000000..225d2b9
> --- /dev/null
> +++ b/tests/overlay/037
> @@ -0,0 +1,144 @@
> +#! /bin/bash
> +# FSQA Test No. 037
> +#
> +# Test constant d_ino numbers
> +#
> +#-----------------------------------------------------------------------
> +#
> +# Copyright (C) 2017 IBM Corporation. All Rights Reserved.
> +# Author: Chandan Rajendra <chandan@linux.vnet.ibm.com>
> +#
> +# 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
> +
> +# real QA test starts here
> +_supported_fs overlay
> +_supported_os Linux
> +_require_scratch
> +_require_test_program "af_unix"
> +_require_test_program "t_dir_type"
> +
> +rm -f $seqres.full
> +
> +_scratch_mkfs >>$seqres.full 2>&1
> +
> +# Create our test files.
> +lowerdir=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER
> +mkdir -p $lowerdir
> +
> +pure_lower_dir=$lowerdir/pure_lower_dir
> +impure_dir=$lowerdir/impure_dir

You name this dir "impure", but I don't see anything impure about it
in the test.
Maybe it is a good idea to repeat the d_ino tests on impure_dir before and after
dir becomes impure.
The readdir code logic is really different depending on dir impure xattr.
although it should not affect results of d_ino for . and .. its a good
idea to verify that.
Besides, its good to verify that readdir cache is correctly
invalidated when pure
dir becomes impure and it would be also good to verify that cache is invalidated
when impure dir becomes pure again (bonus for checking that impure
xattr is removed)

> +merged_dir=$lowerdir/merged_dir
> +
> +mkdir $pure_lower_dir
> +mkdir $impure_dir
> +mkdir $merged_dir
> +
> +impure_dir_st_ino=$(stat -c '%i' $impure_dir)
> +pure_lower_dir_st_ino=$(stat -c '%i' $pure_lower_dir)
> +

Its better that tests restrict themselves to verifying requirements.
It is required that overlay d_ino == overlay st_ino.
It is NOT required that overlay d_ino == real st_ino and future
implementation may change that, so please get all the values of $XXX_st_ino
from stat on overlay mount of respective dir.

> +_scratch_mount
> +
> +impure_dir=$SCRATCH_MNT/impure_dir
> +pure_upper_dir=$impure_dir/pure_upper_dir
> +
> +mkdir -p $pure_upper_dir
> +
> +# Parent's (i.e. "..") d_ino must always be calculated because a pure
> +# dir can be residing inside a merged dir.
> +parent_d=$($here/src/t_dir_type $pure_upper_dir $impure_dir_st_ino)
> +[[ $parent_d != ".. d" ]] && \
> +       echo "Pure dir inside a merged dir: Invalid d_ino reported for .."
> +
> +# d_ino for "." must always be calculated because the present
> +# directory can have a copy-up origin.
> +current_d=$($here/src/t_dir_type $impure_dir $impure_dir_st_ino)
> +[[ $current_d != ". d" ]] && echo "Impure dir: Invalid d_ino reported for ."
> +
> +# Verify d_ino values corresponding to "." and ".." entries of a
> +# pure lower dir.
> +ovl_root_st_ino=$(stat -c '%i' $SCRATCH_MNT/)

It's a bit bold to assume that root inode behaves like any other inode.
Code may change in the future to return constant ino (2) for root like
many fs do. It would be less controversial for the test to work with a
normal dir, so please add another level of dir like you did in multi lower
test below. Also, not a must, but it would have been nicer to read the
test if both test setups (multi and single lower) actually used the same
dir structure.


> +pure_lower_dir=$SCRATCH_MNT/pure_lower_dir
> +
> +parent_d=$($here/src/t_dir_type $pure_lower_dir $ovl_root_st_ino)
> +[[ $parent_d != ".. d" ]] && echo "Pure lower dir: Invalid d_ino reported for .."
> +
> +current_d=$($here/src/t_dir_type $pure_lower_dir $pure_lower_dir_st_ino)
> +[[ $current_d != ". d" ]] && echo "Pure lower dir: Invalid d_ino reported for ."
> +
> +# Verify d_ino of ".." entry of a merged dir.
> +merged_dir=$SCRATCH_MNT/merged_dir
> +touch $merged_dir/file.bin
> +
> +parent_d=$($here/src/t_dir_type $merged_dir $ovl_root_st_ino)
> +[[ $parent_d != ".. d" ]] && echo "Merged dir: Invalid d_ino reported for .."
> +
> +_scratch_unmount
> +
> +# Verify pure lower residing in dir which has another lower layer
> +_scratch_mkfs
> +
> +OVL_LOWER0=${OVL_LOWER}0
> +OVL_LOWER1=${OVL_LOWER}1
> +
> +mkdir -p $OVL_BASE_SCRATCH_MNT/$OVL_LOWER0
> +mkdir -p $OVL_BASE_SCRATCH_MNT/$OVL_LOWER1
> +mkdir -p $OVL_BASE_SCRATCH_MNT/$OVL_UPPER
> +mkdir -p $OVL_BASE_SCRATCH_MNT/$OVL_WORK
> +
> +lowerdir0=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER0
> +lowerdir1=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER1
> +upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
> +workdir=$OVL_BASE_SCRATCH_MNT/$OVL_WORK
> +
> +mkdir -p $lowerdir0/dir0
> +mkdir -p $lowerdir1/dir0/dir1
> +
> +dir0_st_ino=$(stat -c '%i' $lowerdir0/dir0)
> +
> +$MOUNT_PROG -t overlay overlay -o lowerdir=$lowerdir0:$lowerdir1 \
> +           -o upperdir=$upperdir -o workdir=$workdir $SCRATCH_MNT

I find it confusing to understand (an already confusing setup) when lower0
is the middle and not lowermost layer.
Myabe best to describe them as $lowerdir and $middir for clarity.

> +
> +# Copy-up dir0
> +touch $SCRATCH_MNT/dir0/file.bin
> +
> +parent_d=$($here/src/t_dir_type $SCRATCH_MNT/dir0/dir1 $dir0_st_ino)
> +[[ $parent_d != ".. d" ]] && \
> +       echo "Pure lower in dir which has another lower layer: Invalid d_ino reported for .."
> +
> +$UMOUNT_PROG $SCRATCH_MNT
> +
> +echo "Silence is golden"
> +status=0
> +exit
> diff --git a/tests/overlay/037.out b/tests/overlay/037.out
> new file mode 100644
> index 0000000..5c3a30a
> --- /dev/null
> +++ b/tests/overlay/037.out
> @@ -0,0 +1,2 @@
> +QA output created by 037
> +Silence is golden
> diff --git a/tests/overlay/group b/tests/overlay/group
> index 4cc1d74..b2460e1 100644
> --- a/tests/overlay/group
> +++ b/tests/overlay/group
> @@ -39,3 +39,4 @@
>  034 auto quick copyup hardlink
>  035 auto quick mount
>  036 auto quick mount
> +037 auto quick copyup
> --
> 2.9.5
>