On Sun, Jul 08, 2018 at 12:59:57AM +0800, Zorro Lang wrote: > If a user constructs a test that loops repeatedly over below steps > on dm-thin, block allocation can fail due to discards not having > completed yet (Fixed by a685557 dm thin: handle running out of data > space vs concurrent discard): > 1) fill thin device via filesystem file > 2) remove file > 3) fstrim > > And this maybe cause a deadlock (fast device likes ramdisk can help > a lot) when racing a fstrim with a filesystem (XFS) shutdown. (Fixed > by 8c81dd46ef3c Force log to disk before reading the AGF during a > fstrim) > > This case can reproduce both two bugs if they're not fixed. If only > the dm-thin bug is fixed, then the test will pass. If only the fs > bug is fixed, then the test will fail. If both of bugs aren't fixed, > the test will hang. > > Signed-off-by: Zorro Lang <zlang@xxxxxxxxxx> > --- > > Hi, > > V1 as below: > https://marc.info/?l=linux-xfs&m=153070947925942&w=2 > > V2 did below changes: > 1) Use _require_batched_discard to check $FSTRIM_PROG is exist, > and SCRATCH_DEV supports discard. > 2) Reduce the looping times from 100 to 20. > > Thanks, > Zorro > > tests/generic/499 | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++ > tests/generic/499.out | 2 ++ > tests/generic/group | 1 + > 3 files changed, 94 insertions(+) > create mode 100755 tests/generic/499 > create mode 100644 tests/generic/499.out > > diff --git a/tests/generic/499 b/tests/generic/499 > new file mode 100755 > index 00000000..6075509f > --- /dev/null > +++ b/tests/generic/499 > @@ -0,0 +1,91 @@ > +#! /bin/bash > +# SPDX-License-Identifier: GPL-2.0 > +# Copyright (c) 2018 Red Hat Inc. All Rights Reserved. > +# > +# FS QA Test 499 > +# > +# Race test running out of data space with concurrent discard operation on > +# dm-thin. > +# > +# If a user constructs a test that loops repeatedly over below steps on > +# dm-thin, block allocation can fail due to discards not having completed > +# yet (Fixed by a685557 dm thin: handle running out of data space vs ^^^^^^^ better to use 12-digits commit id > +# concurrent discard): > +# 1) fill thin device via filesystem file > +# 2) remove file > +# 3) fstrim > +# > +# And this maybe cause a deadlock when racing a fstrim with a filesystem > +# (XFS) shutdown. (Fixed by 8c81dd46ef3c Force log to disk before reading > +# the AGF during a fstrim) > +# > +seq=`basename $0` > +seqres=$RESULT_DIR/$seq > +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.* > + _dmthin_cleanup > +} > + > +# get standard environment, filters and checks > +. ./common/rc > +. ./common/dmthin > + > +# remove previous $seqres.full before test > +rm -f $seqres.full > + > +# real QA test starts here > +_supported_fs generic > +_supported_os Linux > +_require_scratch_nocheck > +_require_dm_target thin-pool > + > +# Require underlying device support discard > +_scratch_mkfs mkfs output breaks the test here. > +_scratch_mount > +_require_batched_discard $SCRATCH_MNT > +_scratch_unmount > + > +# Create a thin pool and a *slightly smaller* thin volume, it's helpful > +# to reproduce the bug > +BACKING_SIZE=$((50 * 1024 * 1024 / 512)) # 50M > +VIRTUAL_SIZE=$((BACKING_SIZE + 1024)) # 50M + 1k virtual size is too small for btrfs, and _mkfs_dev fails. Otherwise looks fine to me. Thanks, Eryu > +CLUSTER_SIZE=$((64 * 1024 / 512)) # 64K > + > +_dmthin_init $BACKING_SIZE $VIRTUAL_SIZE $CLUSTER_SIZE 0 > +_dmthin_set_fail > +_mkfs_dev $DMTHIN_VOL_DEV > +_dmthin_mount > + > +# There're two bugs at here, one is dm-thin bug, the other is filesystem > +# (XFS especially) bug. The dm-thin bug can't handle running out of data > +# space with concurrent discard well. Then the dm-thin bug cause fs unmount > +# hang when racing a fstrim with a filesystem shutdown. > +# > +# If both of two bugs haven't been fixed, below test maybe cause deadlock. > +# Else if the fs bug has been fixed, but the dm-thin bug hasn't. below test > +# will cause the test fail (no deadlock). > +# Else the test will pass. > +for ((i=0; i<20; i++)); do > + $XFS_IO_PROG -f -c "pwrite -b 64k 0 100M" \ > + $SCRATCH_MNT/testfile &>/dev/null > + rm -f $SCRATCH_MNT/testfile > + $FSTRIM_PROG $SCRATCH_MNT > +done > + > +_dmthin_check_fs > +_dmthin_cleanup > + > +echo "Silence is golden" > + > +# success, all done > +status=0 > +exit > diff --git a/tests/generic/499.out b/tests/generic/499.out > new file mode 100644 > index 00000000..c363e684 > --- /dev/null > +++ b/tests/generic/499.out > @@ -0,0 +1,2 @@ > +QA output created by 499 > +Silence is golden > diff --git a/tests/generic/group b/tests/generic/group > index 83a6fdab..bbeac4af 100644 > --- a/tests/generic/group > +++ b/tests/generic/group > @@ -501,3 +501,4 @@ > 496 auto quick swap > 497 auto quick swap collapse > 498 auto quick log > +499 auto thin trim > -- > 2.14.4 > > -- > To unsubscribe from this list: send the line "unsubscribe fstests" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
