From: Eric Sandeen Subject: [PATCH] xfstests: test ext4 statfs Date: Thu, 25 Oct 2012 12:19:24 -0500 Message-ID: <5089749C.4050003@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: xfs-oss , ext4 development Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35389 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935930Ab2JYRT2 (ORCPT ); Thu, 25 Oct 2012 13:19:28 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: 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 --- 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 +# +# 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 + +# 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 + +# minix should be exactly equal (hence tolerance of 0) +_within_tolerance "minix f_blocks" $MINIX_F_BLOCKS $TOTAL_BLOCKS 0 -v +# 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