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Message-ID: <508AD066.4090102@sgi.com>
Date: Fri, 26 Oct 2012 13:03:18 -0500
From: Rich Johnston <rjohnston@....com>
To: Eric Sandeen <sandeen@...hat.com>
CC: xfs-oss <xfs@....sgi.com>,
ext4 development <linux-ext4@...r.kernel.org>
Subject: Re: xfstests: test ext4 statfs
On 10/25/2012 12:19 PM, Eric Sandeen wrote:
> Calculating free blocks in ext[234] is surprisingly hard, since
> by default we report "bsd" style df which doesn't count filesystem
> "overhead" blocks as used.
>
> With a lot of code dedicated to sorting out what to report as
> free, things tend to go wrong surprisingly often.
>
> Here's a test to actually try to stop the next regression. ;)
>
> NB: For bsddf, the kernel currently does not count journal blocks
> as overhead; it probably should. But the test below looks to have
> the result within 1% of perfection, so it still passes even if
> the kernel doesn't count the journal against free blocks.
>
> Signed-off-by: Eric Sandeen <sandeen@...hat.com>
>
> ---
>
>
> diff --git a/289 b/289
> new file mode 100755
> index 0000000..bf0e897
> --- /dev/null
> +++ b/289
> @@ -0,0 +1,103 @@
> +#! /bin/bash
> +# FS QA Test No. 286
^
289
I know this may change at commit time. ;)
> +#
> +# 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# ./check 289
FSTYP -- ext4
PLATFORM -- Linux/x86_64 cxfsxe4 3.7.0-rc2+
MKFS_OPTIONS -- /dev/sdc2
MOUNT_OPTIONS -- -o acl,user_xattr /dev/sdc2 /xfs_scratch
289 - output mismatch (see 289.out.bad)
--- 289.out 2012-10-26 12:33:27.000000000 -0500
+++ 289.out.bad 2012-10-26 12:35:03.000000000 -0500
@@ -1,3 +1,4 @@
QA output created by 289
-minix f_blocks is in range
+minix f_blocks has value of 7208959
+minix f_blocks is NOT in range 7323904 .. 7323904
bsd f_blocks is in range
Ran: 289
Failures: 289
Failed 1 of 1 tests
> +
> +# 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
> +
> +# Get the honest truth about block counts straight from metadata on disk
> +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 $3}'`
> +
> +# nb: kernels today don't count journal blocks as overhead, but should.
> +# For most filesystems this will still be within tolerance.
> +# Overhead is all the blocks (already) used by the fs itself:
> +OVERHEAD=$(($TOTAL_BLOCKS-$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 this; we get f_blocks from that, which
> +# varies depending on the df mount options used below:
> +
> +# File: "/mnt/test"
> +# ID: affc5f2b2f57652 Namelen: 255 Type: ext2/ext3
> +# Block size: 4096 Fundamental block size: 4096
> +# Blocks: Total: 5162741 Free: 5118725 Available: 4856465
> +# Inodes: Total: 1313760 Free: 1313749
> +
> +_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 data to $seq.full for analysis
> +echo "Overhead is $OVERHEAD blocks out of $TOTAL_BLOCKS ($FREE_BLOCKS free)" >> $seq.full
> +echo "MINIX free blocks $MINIX_F_BLOCKS" >> $seq.full
> +echo "BSD free blocks $BSD_F_BLOCKS" >> $seq.full
> +
This passes for ext[23] but not ext4.
> +# minix should be exactly equal (hence tolerance of 0)
> +_within_tolerance "minix f_blocks" $MINIX_F_BLOCKS $TOTAL_BLOCKS 0 -v
This is what I got when I ran it on an 80G SSD.
Model: ATA INTEL SSDSA2M080 (scsi)
Disk /dev/sdc: 80.0GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt_sync_mbr
Number Start End Size File system Name Flags
1 17.4kB 30.0GB 30.0GB ext4 primary
2 30.0GB 60.0GB 30.0GB ext4 primary
# ./check 289
FSTYP -- ext4
PLATFORM -- Linux/x86_64 cxfsxe4 3.7.0-rc2+
MKFS_OPTIONS -- /dev/sdc2
MOUNT_OPTIONS -- -o acl,user_xattr /dev/sdc2 /xfs_scratch
289 - output mismatch (see 289.out.bad)
--- 289.out 2012-10-26 12:33:27.000000000 -0500
+++ 289.out.bad 2012-10-26 12:35:03.000000000 -0500
@@ -1,3 +1,4 @@
QA output created by 289
-minix f_blocks is in range
+minix f_blocks has value of 7208959
+minix f_blocks is NOT in range 7323904 .. 7323904
bsd f_blocks is in range
Ran: 289
Failures: 289
Failed 1 of 1 tests
> +# bsd should be within ... we'll say 1% for some slop
> +_within_tolerance "bsd f_blocks" $BSD_F_BLOCKS $(($TOTAL_BLOCKS-$OVERHEAD)) 1% -v
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/289.out b/289.out
> new file mode 100644
> index 0000000..a4de760
> --- /dev/null
> +++ b/289.out
> @@ -0,0 +1,3 @@
> +QA output created by 289
> +minix f_blocks is in range
> +bsd f_blocks is in range
> diff --git a/group b/group
> index fb0f8eb..a846b60 100644
> --- a/group
> +++ b/group
> @@ -407,3 +407,4 @@ deprecated
> 286 other
> 287 auto dump quota quick
> 288 auto quick ioctl trim
> +289 auto quick
>
Regards
--Rich
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