From: Lukas Czerner Subject: [PATCH v2] generic: test data corruption on ext4 caused by written/delayed extent Date: Fri, 24 Apr 2015 13:01:24 +0200 Message-ID: <1429873284-19315-1-git-send-email-lczerner@redhat.com> References: <20150423034909.GS17534@dhcp-13-216.nay.redhat.com> Cc: linux-ext4@vger.kernel.org, eguan@redhat.com, Lukas Czerner To: fstests@vger.kernel.org Return-path: In-Reply-To: <20150423034909.GS17534@dhcp-13-216.nay.redhat.com> Sender: fstests-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org This test exercises the problem with unwritten and delayed extents in ext4 extent status tree where we might in some cases lose a block worth of data. Even though this was a ext4 specific problem the reproducer can be easily tun on any file system so let's do that just in case. This tests exercises the problem fixed in kernel with commit "ext4: Fix data corruption caused by unwritten and delayed extents" Signed-off-by: Lukas Czerner --- tests/generic/082 | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++ tests/generic/082.out | 14 +++++++++ tests/generic/group | 1 + 3 files changed, 100 insertions(+) create mode 100755 tests/generic/082 create mode 100644 tests/generic/082.out diff --git a/tests/generic/082 b/tests/generic/082 new file mode 100755 index 0000000..e9bdd11 --- /dev/null +++ b/tests/generic/082 @@ -0,0 +1,85 @@ +#! /bin/bash +# FS QA Test 082 +# +# This test excercises the problem with unwritten and delayed extents +# in ext4 extent status tree where we might in some cases lose a block +# worth of data. Even though this was a ext4 specific problem the +# reproducer can be easily tun on any file system so let's do that just +# in case. +# +# This tests excercises the problem fixed in kernel with commit +# "ext4: Fix data corruption caused by unwritten and delayed extents" +# +#----------------------------------------------------------------------- +# Copyright (c) 2015 Red Hat, Inc., Lukas Czerner +# +# 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" + +here=`pwd` +tmp=/tmp/$$ +status=1 # failure is the default! +trap "_cleanup; exit \$status" 0 1 2 3 15 + +_cleanup() +{ + cd / + rm -f $tmp.* +} + +# get standard environment, filters and checks +. ./common/rc +. ./common/filter + +# real QA test starts here + +# Modify as appropriate. +_supported_fs generic +_supported_os IRIX Linux +_require_test +_require_xfs_io_command "falloc" + +test_file=${TEST_DIR}/testfile-$seq + +rm -f $test_file + +# The first write creates a delayed extent, fallocate creates +# unwritten extent which will be marked as delayed in ext4 +# extent status tree. Second write will convert unwritten/delayed +# block into written/delayed. +$XFS_IO_PROG -f -c "pwrite -S 0xaa 4096 2048" \ + -c "falloc 0 131072" \ + -c "pwrite -S 0xbb 65536 2048" \ + -c "fsync" $test_file > $seqres.full 2>&1 + +# Drop the caches to evict dirty buffers from memory +echo 3 > /proc/sys/vm/drop_caches + +# Write into the second part of the block with 0xbb write from before +# will create new empty! buffer because the block is still marked as +# delayed even though it's already written - resulting in +# overwriting previous data. +$XFS_IO_PROG -c "pwrite -S 0xdd 67584 2048" $test_file >> $seqres.full 2>&1 + +# On a faulty ext4 oxbb data will be missing, overwritten by zeroes. +hexdump -C $test_file + +# success, all done +status=0 +exit diff --git a/tests/generic/082.out b/tests/generic/082.out new file mode 100644 index 0000000..ef28b9a --- /dev/null +++ b/tests/generic/082.out @@ -0,0 +1,14 @@ +QA output created by 082 +00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| +* +00001000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa |................| +* +00001800 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| +* +00010000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb |................| +* +00010800 dd dd dd dd dd dd dd dd dd dd dd dd dd dd dd dd |................| +* +00011000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| +* +00020000 diff --git a/tests/generic/group b/tests/generic/group index 63b883c..c6ea3d8 100644 --- a/tests/generic/group +++ b/tests/generic/group @@ -84,6 +84,7 @@ 079 acl attr ioctl metadata auto quick 080 auto quick 081 auto quick +082 auto prealloc preallocrw quick 083 rw auto enospc stress 088 perms auto quick 089 metadata auto -- 1.8.3.1