Message-ID: <CA+dCu8936Jrwi2tVh6Yx10-Nb8jSZOx+m+Ho34oVYY1sJsh=Yw@mail.gmail.com>
Date:	Thu, 6 Sep 2012 16:49:57 +0800
From:	Eryu Guan <guaneryu@...il.com>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	xfs-oss <xfs@....sgi.com>,
	ext4 development <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] xfstests 285: verify extN statfs f_blocks

On Thu, Sep 6, 2012 at 6:20 AM, Eric Sandeen <sandeen@...hat.com> wrote:
> extN can report f_blocks in statfs in 2 different ways, based
> on whether or not metadata overhead is counted.  This has broken
> in the past, so here's a test for it.
>
> It looks at dumpe2fs output to get total blocks and free blocks
> right after mkfs.  The difference should be, by definition, the
> exact amount of metadata overhead.
>
> It then compares this to what's reported via stat -f for f_blocks.
> For "minix" df, it should be exactly equal to the total blocks,
> and for "bsd" df, it should be total blocks less overhead.
>
> It tests that the latter is accurate to within a 1% tolerance.
>
> Today the journal doesn't count as overhead in the statfs call;
> this should be fixed kernelside but for many filesystems it'll be
> within the threshold anyway.
>
> Signed-off-by: Eric Sandeen <sandeen@...hat.com>
> ---
>
> diff --git a/285 b/285
> new file mode 100755
> index 0000000..cda8531
> --- /dev/null
> +++ b/285
> @@ -0,0 +1,97 @@
> +#! /bin/bash
> +# FS QA Test No. 286

The Test No. should be 285 here?
> +#
> +# Test overhead & df output for extN filesystems
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2012 Red Hat, Inc.  All Rights Reserved.
> +#
> +# 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
> +#-----------------------------------------------------------------------
> +#
> +# creator
> +owner=sandeen@...hat.com
> +
> +seq=`basename $0`
> +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
> +
> +# Modify as appropriate.
> +_supported_fs ext2 ext3 ext4
> +_supported_os Linux
> +_require_scratch
> +
> +rm -f $seq.full
> +
> +_scratch_mkfs >> $seq.full 2>&1
> +
> +TOTAL_BLOCKS=`dumpe2fs -h $SCRATCH_DEV 2>/dev/null \
> +               | awk '/Block count:/{print $3}'`
> +
> +FREE_BLOCKS=`dumpe2fs -h $SCRATCH_DEV 2>/dev/null \
> +               | awk '/Free blocks:/{print $3}'`

I guess TOTAL_BLOCKS and FREE_BLOCKS will be wrong when testing ext4
on RHEL5 which has a separate dumpe4fs for ext4.

Thanks,
Eryu Guan
> +
> +# nb: kernels today don't count journal blocks  as overhead, but should.
> +# For most fileystems this will still be within tolerance.
> +OVERHEAD=$(($TOTAL_BLOCKS-$FREE_BLOCKS))
> +
> +#  bsddf|minixdf
> +#         Set the behaviour  for  the  statfs  system  call.  The  minixdf
> +#         behaviour is to return in the f_blocks field the total number of
> +#         blocks of the filesystem, while the bsddf  behaviour  (which  is
> +#         the default) is to subtract the overhead blocks used by the ext2
> +#         filesystem and not available for file storage.
> +
> +# stat -f output looks like; we get f_blocks from that, which
> +# varies depending on the df mount options used below:
> +
> +# Filesystem           4K-blocks      Used Available Use% Mounted on
> +# /dev/sda8              2405312   2208933    196379  92% /
> +
> +_scratch_mount "-o minixdf"
> +MINIX_F_BLOCKS=`stat -f $SCRATCH_MNT | awk '/^Blocks/{print $3}'`
> +umount $SCRATCH_MNT
> +
> +_scratch_mount "-o bsddf"
> +BSD_F_BLOCKS=`stat -f $SCRATCH_MNT | awk '/^Blocks/{print $3}'`
> +umount $SCRATCH_MNT
> +
> +echo "Overhead is $OVERHEAD out of $TOTAL_BLOCKS" >> $seq.full
> +echo "BSD blocks $BSD_F_BLOCKS" >> $seq.full
> +echo "MINIX blocks $MINIX_F_BLOCKS" >> $seq.full
> +
> +# minix should be exactly equal (hence 0)
> +_within_tolerance "minix f_blocks" $MINIX_F_BLOCKS $TOTAL_BLOCKS 0 -v
> +# bsd should be within ... we'll say 1%
> +_within_tolerance "bsd f_blocks" $BSD_F_BLOCKS $(($TOTAL_BLOCKS-$OVERHEAD)) 1% -v
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/285.out b/285.out
> new file mode 100644
> index 0000000..2075e21
> --- /dev/null
> +++ b/285.out
> @@ -0,0 +1,3 @@
> +QA output created by 285
> +minix f_blocks is in range
> +bsd f_blocks is in range
> diff --git a/group b/group
> index 104ed35..0b33178 100644
> --- a/group
> +++ b/group
> @@ -403,3 +403,4 @@ deprecated
>  282 dump ioctl auto quick
>  283 dump ioctl auto quick
>  284 auto
> +285 auto
>
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