Re: xfstests: test ext4 statfs

[Rich Johnston <rjohnston@sgi.com>]

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@redhat.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@redhat.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