| Message ID | 20180323052540.GZ30836@localhost.localdomain (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Fri, Mar 23, 2018 at 01:26:06PM +0800, Eryu Guan wrote: > On Wed, Mar 21, 2018 at 09:57:16AM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong <darrick.wong@oracle.com> > > > > From the kernel patch that this test examines ("xfs: detect agfl count > > corruption and reset agfl"): > > > > "The struct xfs_agfl v5 header was originally introduced with > > unexpected padding that caused the AGFL to operate with one less > > slot than intended. The header has since been packed, but the fix > > left an incompatibility for users who upgrade from an old kernel > > with the unpacked header to a newer kernel with the packed header > > while the AGFL happens to wrap around the end. The newer kernel > > recognizes one extra slot at the physical end of the AGFL that the > > previous kernel did not. The new kernel will eventually attempt to > > allocate a block from that slot, which contains invalid data, and > > cause a crash. > > > > "This condition can be detected by comparing the active range of the > > AGFL to the count. While this detects a padding mismatch, it can > > also trigger false positives for unrelated flcount corruption. Since > > we cannot distinguish a size mismatch due to padding from unrelated > > corruption, we can't trust the AGFL enough to simply repopulate the > > empty slot. > > > > "Instead, avoid unnecessarily complex detection logic and and use a > > solution that can handle any form of flcount corruption that slips > > through read verifiers: distrust the entire AGFL and reset it to an > > empty state. Any valid blocks within the AGFL are intentionally > > leaked. This requires xfs_repair to rectify (which was already > > necessary based on the state the AGFL was found in). The reset > > mitigates the side effect of the padding mismatch problem from a > > filesystem crash to a free space accounting inconsistency." > > > > This test exercises the reset code by mutating a fresh filesystem to > > contain an agfl with various list configurations of correctly wrapped, > > incorrectly wrapped, not wrapped, and actually corrupt free lists; then > > checks the success of the reset operation by fragmenting the free space > > btrees to exercise the agfl. Kernels without this reset fix will shut > > down the filesystem with corruption errors. > > > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > > --- > > v3: use fallocate instead of dd write, more factoring of common code > > v2: remove unncessary umounts, refactor long lines into helpers > > --- > > common/rc | 23 ++++- > > tests/xfs/709 | 258 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > > tests/xfs/709.out | 13 +++ > > tests/xfs/group | 1 > > 4 files changed, 293 insertions(+), 2 deletions(-) > > create mode 100755 tests/xfs/709 > > create mode 100644 tests/xfs/709.out > > > > diff --git a/common/rc b/common/rc > > index 2c29d55..f7eb72d 100644 > > --- a/common/rc > > +++ b/common/rc > > @@ -3440,6 +3440,26 @@ _get_device_size() > > grep `_short_dev $1` /proc/partitions | awk '{print $3}' > > } > > > > +# Make sure we actually have dmesg checking set up. > > +_require_check_dmesg() { > > + test -w /dev/kmsg || \ > > + _notrun "Test requires writable /dev/kmsg." > > +} > > + > > +# Return the dmesg log since the start of this test. Caller must ensure that > > +# /dev/kmsg was writable when the test was started so that we can find the > > +# beginning of this test's log messages; _require_check_dmesg does this. > > +_dmesg_since_test_start() { > > + dmesg | tac | sed -ne "0,\#run fstests $seqnum at $date_time#p" | \ > > + tac > > +} > > + > > +# check dmesg log for a specific string, subject to the same requirements as > > +# _dmesg_since_test_start. > > +_check_dmesg_for() { > > + _dmesg_since_test_start | egrep -q "$1" > > +} > > + > > # check dmesg log for WARNING/Oops/etc. > > _check_dmesg() > > { > > @@ -3455,8 +3475,7 @@ _check_dmesg() > > > > # search the dmesg log of last run of $seqnum for possible failures > > # use sed \cregexpc address type, since $seqnum contains "/" > > The comments about sed usage probably should go to > _dmesg_since_test_start() too. Ok > > - dmesg | tac | sed -ne "0,\#run fstests $seqnum at $date_time#p" | \ > > - tac | $filter >$seqres.dmesg > > + _dmesg_since_test_start | $filter >$seqres.dmesg > > egrep -q -e "kernel BUG at" \ > > -e "WARNING:" \ > > -e "BUG:" \ > > diff --git a/tests/xfs/709 b/tests/xfs/709 > > new file mode 100755 > > index 0000000..78cefe5 > > --- /dev/null > > +++ b/tests/xfs/709 > > @@ -0,0 +1,258 @@ > > +#! /bin/bash > > +# FS QA Test No. 709 > > +# > > +# Make sure XFS can fix a v5 AGFL that wraps over the last block. > > +# Refer to commit 96f859d52bcb ("libxfs: pack the agfl header structure so > > +# XFS_AGFL_SIZE is correct") for details on the original on-disk format error > > +# and the patch "xfs: detect agfl count corruption and reset agfl") for details > > +# about the fix. > > +# > > +#----------------------------------------------------------------------- > > +# Copyright (c) 2018 Oracle, Inc. > > +# > > +# 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 > > +trap "_cleanup; rm -f $tmp.*; exit \$status" 0 1 2 3 15 > > + > > +_cleanup() > > +{ > > + cd / > > + rm -f $tmp.* > > +} > > + > > +rm -f $seqres.full > > + > > +# get standard environment, filters and checks > > +. ./common/rc > > +. ./common/filter > > + > > +# real QA test starts here > > +_supported_fs xfs > > +_supported_os Linux > > + > > +_require_check_dmesg > > +_require_scratch > > +_require_test_program "punch-alternating" > > + > > +# This is only a v5 filesystem problem > > +_require_scratch_xfs_crc > > + > > +mount_loop() { > > + if ! _try_scratch_mount >> $seqres.full 2>&1; then > > + echo "scratch mount failed" >> $seqres.full > > + return > > + fi > > + > > + # Trigger agfl fixing by fragmenting free space enough to cause > > + # a bnobt split > > + blksz=$(_get_file_block_size ${SCRATCH_MNT}) > > + bno_maxrecs=$(( blksz / 8 )) > > + filesz=$((bno_maxrecs * 3 * blksz)) > > + rm -rf $SCRATCH_MNT/a > > + $XFS_IO_PROG -f -c "falloc 0 $filesz" $SCRATCH_MNT/a > > And I noticed test failure with patch "xfs: detect agfl count corruption > and reset agfl" applied on top of 4.16-rc5 kernel. Looks like we should > dump xfs_io output to $seqres.full, as in v2 patch > > dd if=/dev/zero of=$SCRATCH_MNT/a bs=8192k >> $seqres.full 2>&1 Yep. In the bad_start case the fs checks every agfl and refuses to mount... if your kernel has CONFIG_XFS_DEBUG=y. > --- tests/xfs/709.out 2018-03-23 12:45:16.831011711 +0800 > +++ /root/workspace/xfstests/results//xfs_4k_crc/xfs/709.out.bad 2018-03-23 13:12:10.083980820 +0800 > @@ -7,6 +7,7 @@ > TEST good_start > TEST good_wrap > TEST bad_start > +fallocate: Structure needs cleaning > ASSERT flfirst < good_agfl_size - 1 > ASSERT flfirst < fllast > TEST no_move > > > + test -e $SCRATCH_MNT/a && ./src/punch-alternating $SCRATCH_MNT/a > > + rm -rf $SCRATCH_MNT/a > > + > > + _scratch_unmount 2>&1 | _filter_scratch > > +} > > + > > +dump_ag0() { > > + _scratch_xfs_db -c 'sb 0' -c 'p' -c 'agf 0' -c 'p' -c 'agfl 0' -c 'p' > > +} > > + > > +runtest() { > > + cmd="$1" > > + > > + # Format filesystem > > + echo "TEST $cmd" | tee /dev/ttyprintk > > What's the purpose of writing to /dev/ttyprintk? I don't see how it's > used in the test. It makes it easy to tell which kernel messages came from which runtest() invocation so that we can tell if a particular agfl mutation test actually triggered the fixup. --D > Thanks, > Eryu > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Mar 23, 2018 at 09:08:17AM -0700, Darrick J. Wong wrote: > > > + > > > + # Format filesystem > > > + echo "TEST $cmd" | tee /dev/ttyprintk > > > > What's the purpose of writing to /dev/ttyprintk? I don't see how it's > > used in the test. > > It makes it easy to tell which kernel messages came from which runtest() > invocation so that we can tell if a particular agfl mutation test > actually triggered the fixup. This could fail the test if /dev/ttyprintk doesn't exist. It seems writing to /dev/kmsg works could tell us the same information, and we've already made sure /dev/kmsg is writable by _require_check_dmesg. IMHO /dev/kmsg might be a better choice here. Thanks, Eryu -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Mar 26, 2018 at 09:22:53AM +0800, Eryu Guan wrote: > On Fri, Mar 23, 2018 at 09:08:17AM -0700, Darrick J. Wong wrote: > > > > + > > > > + # Format filesystem > > > > + echo "TEST $cmd" | tee /dev/ttyprintk > > > > > > What's the purpose of writing to /dev/ttyprintk? I don't see how it's > > > used in the test. > > > > It makes it easy to tell which kernel messages came from which runtest() > > invocation so that we can tell if a particular agfl mutation test > > actually triggered the fixup. > > This could fail the test if /dev/ttyprintk doesn't exist. It seems Correction, it doesn't fail the test, but creates a new /dev/ttyprintk file.. but still, I think this should be addressed. Rather than that, the test runs good for me, it fails with 4.16-rc7 kernel and passes with the mentioned patch applied. Brian, would you please help review the new version of this patch in patchset "[PATCH 0/4] misc. fstests changes" (patch 3/4) as well? I really like a Reviewed-by tag from someone who knows all the details of the test and the fix :) Thanks a lot! Eryu > writing to /dev/kmsg works could tell us the same information, and we've > already made sure /dev/kmsg is writable by _require_check_dmesg. IMHO > /dev/kmsg might be a better choice here. > > Thanks, > Eryu -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- tests/xfs/709.out 2018-03-23 12:45:16.831011711 +0800 +++ /root/workspace/xfstests/results//xfs_4k_crc/xfs/709.out.bad 2018-03-23 13:12:10.083980820 +0800 @@ -7,6 +7,7 @@ TEST good_start TEST good_wrap TEST bad_start +fallocate: Structure needs cleaning ASSERT flfirst < good_agfl_size - 1 ASSERT flfirst < fllast TEST no_move