On Mon, Mar 30, 2015 at 03:11:06PM -0400, Jeff Mahoney wrote:
> This tests tests four conditions where discard can potentially not
> discard unused extents completely.
>
> We test, with -o discard and with fstrim, scenarios of removing many
> relatively small files and removing several large files.
>
> The important part of the two scenarios is that the large files must be
> large enough to span a blockgroup alone. It's possible for an
> entire block group to be emptied and dropped without an opportunity to
> discard individual extents as would happen with smaller files.
>
> The test confirms the discards have occured by using a sparse file
> mounted via loopback to punch holes and then check how many blocks
> are still allocated within the file.
>
> Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
> ---
The code looks mostly Ok to me, a few notes below. Those aside, this is
a longish test. It takes me about 8 minutes to run on my typical low end
vm.
Is the 1GB block group magic value mutable in any way, or is it a
hardcoded thing (for btrfs I presume)? It would be nice if we could
shrink that a bit. If not, perhaps there are some other ways to reduce
the runtime...
- Is there any reason a single discard or trim test instance must be all
large or small files? In other words, is there something that this
wouldn't catch if the 10GB were 50% filled with large files and %50 with
small files? That would allow us to trim the maximum on the range of
small file creation and only have two invocations instead of four.
- If the 1GB thing is in fact a btrfs thing, could we make the core test
a bit more size agnostic (e.g., perhaps pass the file count/size
values as parameters) and then scale the parameters up exclusively for
btrfs? For example, set defaults of fssize=1G, largefile=100MB,
smallfile=[512b-5MB] or something of that nature and override them to
the 10GB, 1GB, 32k-... values for btrfs? That way we don't need to write
as much data for fs' where it might not be necessary.
> tests/generic/326 | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++
> tests/generic/326.out | 5 ++
> tests/generic/group | 1 +
> 3 files changed, 170 insertions(+)
> create mode 100644 tests/generic/326
> create mode 100644 tests/generic/326.out
>
> diff --git a/tests/generic/326 b/tests/generic/326
> new file mode 100644
> index 0000000..923a27f
> --- /dev/null
> +++ b/tests/generic/326
> @@ -0,0 +1,164 @@
> +#! /bin/bash
> +# FSQA Test No. 326
> +#
> +# This test uses a loopback mount with PUNCH_HOLE support to test
> +# whether discard operations are working as expected.
> +#
> +# It tests both -odiscard and fstrim.
> +#
> +# Copyright (C) 2015 SUSE. All Rights Reserved.
> +# Author: Jeff Mahoney <jeffm@xxxxxxxx>
> +#
> +# 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
> +#-----------------------------------------------------------------------
> +#
> +
> +seq=`basename $0`
> +seqres=$RESULT_DIR/$seq
> +echo "QA output created by $seq"
> +
> +tmp=/tmp/$$
> +status=1 # failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +loopdev=
> +tmpdir=
> +_cleanup()
> +{
> + [ -n "$tmpdir" ] && umount $tmpdir
> + [ -n "$loopdev" ] && losetup -d $loopdev
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +
> +# real QA test starts here
> +_need_to_be_root
> +_supported_fs generic
> +_supported_os Linux
> +_require_scratch
> +_require_fstrim
> +
> +rm -f $seqres.full
> +
> +_scratch_mkfs &>> $seqres.full
> +_require_fs_space $SCRATCH_MNT $(( 10 * 1024 * 1024 ))
> +_scratch_mount
> +
> +test_discard()
> +{
> + discard=$1
> + files=$2
> +
> + tmpfile=$SCRATCH_MNT/testfs.img.$$
> + tmpdir=$SCRATCH_MNT/testdir.$$
> + mkdir -p $tmpdir || _fail "!!! failed to create temp mount dir"
> +
> + # Create a sparse file to host the file system
> + dd if=/dev/zero of=$tmpfile bs=1M count=1 seek=10240 &> $seqres.full \
> + || _fail "!!! failed to create fs image file"
xfs_io -c "truncate ..." ?
> +
> + opts=""
> + if [ "$discard" = "discard" ]; then
> + opts="-o discard"
> + fi
> + losetup -f $tmpfile
> + loopdev=$(losetup -j $tmpfile|awk -F: '{print $1}')
> + _mkfs_dev $loopdev &> $seqres.full
> + $MOUNT_PROG $opts $loopdev $tmpdir \
> + || _fail "!!! failed to loopback mount"
> +
> + if [ "$files" = "large" ]; then
> + # Create files larger than 1GB so each one occupies
> + # more than one block group
> + for n in $(seq 1 8); do
> + dd if=/dev/zero of=$tmpdir/file$n bs=1M count=1200 \
> + &> $seqres.full
> + done
> + else
> + # Create up to 40k files sized 32k-1GB.
> + mkdir -p $tmpdir/testdir
> + for ((i = 1; i <= 40000; i++)); do
> + SIZE=$(( $((1024*1024*1024)) / $(( $RANDOM + 1 )) ))
> + $XFS_IO_PROG -f -c "pwrite -S 0xaa 0 $SIZE" \
> + $tmpdir/testdir/"${prefix}_$i" &> /dev/null
> + if [ $? -ne 0 ]; then
> + echo "Failed creating file ${prefix}_$i" \
${prefix} doesn't evaluate to anything in my run of this test. $seq
perhaps?
> + >>$seqres.full
> + break
> + fi
> + done
> + fi
> +
> + sync
> + OSIZE="$(du -k $tmpfile|awk '{print $1}')"
> + du -k $tmpfile >> $seqres.full
> +
> + if [ "$files" = "large" ]; then
> + rm $tmpdir/file?
> + else
> + rm -rf $tmpdir/testdir
> + fi
> +
> + # Ensure everything's actually on the hosted file system
> + if [ "$FSTYP" = "btrfs" ]; then
> + _run_btrfs_util_prog filesystem sync $tmpdir
> + fi
> + sync
> + sync
Any reason for the double syncs?
> + if [ "$discard" = "trim" ]; then
> + $FSTRIM_PROG $tmpdir
> + fi
> +
> + $UMOUNT_PROG $tmpdir
> + rmdir $tmpdir
> + tmpdir=
> +
> + # Sync the backing file system to ensure the hole punches have
> + # happened and we can trust the result.
> + if [ "$FSTYP" = "btrfs" ]; then
> + _run_btrfs_util_prog filesystem sync $SCRATCH_MNT
> + fi
> + sync
> + sync
> +
> + NSIZE="$(du -k $tmpfile|awk '{print $1}')"
> + du -k $tmpfile >> $seqres.full
> +
> + # Going from ~ 10GB to 50MB is a good enough test to account for
> + # metadata remaining on different file systems.
> + if [ "$NSIZE" -gt $(( 50 * 1024 )) ]; then
> + _fail "TRIM failed: before rm ${OSIZE}kB, after rm ${NSIZE}kB"
> + fi
> + rm $tmpfile
> + losetup -d $loopdev
> + loopdev=
> +}
> +
> +
> +echo "Testing with -odiscard, many small files"
> +test_discard discard many
> +
> +echo "Testing with -odiscard, several large files"
> +test_discard discard large
> +
> +echo "Testing with fstrim, many small files"
> +test_discard trim many
> +
> +echo "Testing with fstrim, several large files"
> +test_discard trim large
> +
> +status=0
> +exit
> diff --git a/tests/generic/326.out b/tests/generic/326.out
> new file mode 100644
> index 0000000..37b0f2c
> --- /dev/null
> +++ b/tests/generic/326.out
> @@ -0,0 +1,5 @@
> +QA output created by 084
326
Brian
> +Testing with -odiscard, many small files
> +Testing with -odiscard, several large files
> +Testing with fstrim, many small files
> +Testing with fstrim, several large files
> diff --git a/tests/generic/group b/tests/generic/group
> index d56d3ce..75e17fa 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -183,3 +183,4 @@
> 323 auto aio stress
> 324 auto fsr quick
> 325 auto quick data log
> +326 auto metadata
> --
> 1.8.5.6
>
>
> --
> Jeff Mahoney
> SUSE Labs
> --
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