Date:   Sun, 6 Dec 2020 21:50:43 +0800
From:   Eryu Guan <guan@...u.me>
To:     Ritesh Harjani <riteshh@...ux.ibm.com>
Cc:     fstests@...r.kernel.org, linux-ext4@...r.kernel.org,
        anju@...ux.vnet.ibm.com
Subject: Re: [PATCH 2/2] generic: Add test to check for mounting a huge
 sparse dm device

On Fri, Dec 04, 2020 at 04:13:54PM +0530, Ritesh Harjani wrote:
> Add this test to check for regression which was reported when ext4 bmap
> aops was moved to use iomap APIs. jbd2 calls bmap() kernel function
> from fs/inode.c which was failing since iomap_bmap() implementation earlier
> returned 0 for block addr > INT_MAX.
> This regression was fixed with following kernel commit [1]
> commit b75dfde1212991b24b220c3995101c60a7b8ae74
> ("fibmap: Warn and return an error in case of block > INT_MAX")
> [1]: https://patchwork.ozlabs.org/patch/1279914
> 
> w/o the kernel fix we get below errors and mount fails
> 
> [ 1461.988701] run fstests generic/613 at 2020-10-27 19:57:34
> [ 1530.406645] ------------[ cut here ]------------
> [ 1530.407332] would truncate bmap result
> [ 1530.408956] WARNING: CPU: 0 PID: 6401 at fs/iomap/fiemap.c:116
> iomap_bmap_actor+0x43/0x50
> [ 1530.410607] Modules linked in:
> [ 1530.411024] CPU: 0 PID: 6401 Comm: mount Tainted: G        W
> <...>
>  1530.511978] jbd2_journal_init_inode: Cannot locate journal superblock
>  [ 1530.513310] EXT4-fs (dm-1): Could not load journal inode
> 
> Signed-off-by: Ritesh Harjani <riteshh@...ux.ibm.com>
> ---
>  common/rc             | 10 +++++++
>  tests/generic/618     | 70 +++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/618.out |  3 ++
>  tests/generic/group   |  1 +
>  4 files changed, 84 insertions(+)
>  create mode 100755 tests/generic/618
>  create mode 100644 tests/generic/618.out
> 
> diff --git a/common/rc b/common/rc
> index b5a504e0dcb4..128d75226958 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -1608,6 +1608,16 @@ _require_scratch_size()
>  	[ $devsize -lt $1 ] && _notrun "scratch dev too small"
>  }
>  
> +# require a scratch dev of a minimum size (in kb) and should not be checked
> +# post test
> +_require_scratch_size_nocheck()
> +{
> +	[ $# -eq 1 ] || _fail "_require_scratch_size: expected size param"
> +
> +	_require_scratch_nocheck
> +	local devsize=`_get_device_size $SCRATCH_DEV`
> +	[ $devsize -lt $1 ] && _notrun "scratch dev too small"
> +}
>  
>  # this test needs a test partition - check we're ok & mount it
>  #
> diff --git a/tests/generic/618 b/tests/generic/618
> new file mode 100755
> index 000000000000..45c14da80c06
> --- /dev/null
> +++ b/tests/generic/618
> @@ -0,0 +1,70 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2020 Christian Kujau. All Rights Reserved.
> +# Copyright (c) 2020 Ritesh Harjani. All Rights Reserved.
> +#
> +# FS QA Test generic/618
> +#
> +# Since the test is not specific to ext4, hence adding it to generic.
> +# Add this test to check for regression which was reported when ext4 bmap
> +# aops was moved to use iomap APIs. jbd2 calls bmap() kernel function
> +# from fs/inode.c which was failing since iomap_bmap() implementation earlier
> +# returned 0 for block addr > INT_MAX.
> +# This regression was fixed with following kernel commit [1]
> +# commit b75dfde1212991b24b220c3995101c60a7b8ae74
> +# ("fibmap: Warn and return an error in case of block > INT_MAX")
> +# [1]: https://patchwork.ozlabs.org/patch/1279914
> +#
> +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()
> +{
> +	_dmhugedisk_cleanup
> +	cd /
> +	rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +. ./common/dmhugedisk
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# Modify as appropriate.
> +_supported_fs generic
> +_require_dmhugedisk
> +_require_scratch_size_nocheck $((4 * 1024 * 1024)) #kB
> +
> +# For 1k bs with ext4, mkfs was failing due to size limitation and also it
> +# becomes too slow when doing an mkfs on a huge sparse ext4 FS with 1k bs.
> +# Hence on ext4 run only for 4K bs.
> +if [ "$FSTYP" == "ext4" ]; then
> +	_scratch_mkfs > /dev/null 2>&1
> +	blksz=$(sudo debugfs -R stats $SCRATCH_DEV 2> /dev/null |grep "Block size" |cut -d ':' -f 2)
> +	test $blksz -lt 4096 && _notrun "This test requires ext4 with minimum 4k bs"
> +fi

As this is a generic test, the same check should be done with ext2 and
ext3. And actually this test requires > 16T fs support. So I'd suggest
add a new helper, maybe called _require_16T_support, to check if $FSTYP
supports filesystem size > 16T. And for now, we could only check for
extN.

Also, there's no need to run command with sudo in fstests, as all tests
are required to be run by root.

And there's a helper to get fs block size called _get_block_size, no
need to parse output of debugfs.

Thanks,
Eryu

P.S. I've applied patch 1 in the patchset, no need to resend in v2,
thanks!

> +
> +# 17TB dm huge-test-zer0 device
> +# (in terms of 512 sectors)
> +sectors=$((2*1024*1024*1024*17))
> +chunk_size=128
> +
> +_dmhugedisk_init $sectors $chunk_size
> +_mkfs_dev $DMHUGEDISK_DEV
> +_mount $DMHUGEDISK_DEV $SCRATCH_MNT || _fail "mount failed for $DMHUGEDISK_DEV $SCRATCH_MNT"
> +testfile=$SCRATCH_MNT/testfile-$seq
> +
> +$XFS_IO_PROG -fc "pwrite -S 0xaa 0 1m" -c "fsync" $testfile | _filter_xfs_io
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/generic/618.out b/tests/generic/618.out
> new file mode 100644
> index 000000000000..b920fe4d907a
> --- /dev/null
> +++ b/tests/generic/618.out
> @@ -0,0 +1,3 @@
> +QA output created by 618
> +wrote 1048576/1048576 bytes at offset 0
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> diff --git a/tests/generic/group b/tests/generic/group
> index 94e860b8c380..39e3ffb224a9 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 mount quick
> -- 
> 2.26.2

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