On 10/26/12 1:03 PM, Rich Johnston wrote:
> 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@xxxxxxxxxx>
>>
>> ---
>>
>>
>> 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. ;)
meh, right. Dumb to have it in the file, maybe.
>> +#
>> +# 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@xxxxxxxxxx
>> +
>> +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
Yep - it's an ext4 bug. I sent a patch to fix it.
[PATCH] ext4: fix overhead calculations in ext4_stats, again
You might want to retest w/ that.
-Eric
>> +
>> +# 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.
*nod*
>> +# 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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