On Fri, Aug 18, 2017 at 08:47:35AM -0700, Darrick J. Wong wrote:
> On Fri, Aug 18, 2017 at 10:51:56AM +0200, Carlos Maiolino wrote:
> > Tests the search algorithm for a free inode slot in a specific AG, done
> > in xfs_dialloc_ag_inobt().
> >
> > When finobt is not used, and agi->freecount is not 0, XFS will scan the AG inode
> > tree looking for a free inode slot, but if agi->freecount is corrupted,
> > and there is no free slot at all, it will end up in an infinite loop.
> >
> > This test checks for the infinite loop fix.
> >
> > Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
> > ---
> >
> > Changelog:
> >
> > V2:
> > - Small clean up
> > - use _disable_dmesg_check (the test will generate error
> > messages which will appear in dmesg)
> > - Get the amount of free inodes from the AGI instead of assuming
> > 61 free inodes
> > - Send a few outputs to $seqres.full
> > - Use xfs_db `write` without -d option once this will create
> > incompatibility with previous xfsprogs, and is not strictly
> > required for the test to work.
> > - Check for finobt, and explicitly disable it if it is
> > supported by the kernel being tested.
> >
> > V3:
> > - use _scratch_xfs_db helper
> > - ensure the test is only run on kernel with no XFS_DEBUG
>
> Why does !debug matter?
XFS_DEBUG enables xfs_check_agi_freecount(), which will detect the corruption of
agi->freecount.
>
> --D
>
> >
> > tests/xfs/057 | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > tests/xfs/057.out | 2 ++
> > tests/xfs/group | 1 +
> > 3 files changed, 90 insertions(+)
> > create mode 100755 tests/xfs/057
> > create mode 100644 tests/xfs/057.out
> >
> > diff --git a/tests/xfs/057 b/tests/xfs/057
> > new file mode 100755
> > index 00000000..2c866435
> > --- /dev/null
> > +++ b/tests/xfs/057
> > @@ -0,0 +1,87 @@
> > +#! /bin/bash
> > +# FS QA Test 057
> > +#
> > +# Check if the filesystem will lockup when trying to allocate a new inode in
> > +# an AG with no free inodes but with a corrupted agi->freecount showing free inodes.
> > +#
> > +# At the end of the test, the scratch device will purposely be in a corrupted
> > +# state, so there is no need for checking that.
> > +#-----------------------------------------------------------------------
> > +# Copyright (c) 2017 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
> > +#-----------------------------------------------------------------------
> > +#
> > +
> > +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
> > +
> > +# remove previous $seqres.full before test
> > +rm -f $seqres.full
> > +
> > +# real QA test starts here
> > +
> > +# Modify as appropriate.
> > +_supported_fs generic
> > +_supported_os Linux
> > +_require_scratch_nocheck
> > +_require_no_xfs_debug
> > +_disable_dmesg_check
> > +
> > +# Make sure we disable finobt if the filesystem supports it, otherwise, just
> > +# initialize it with default options.
> > +_scratch_mkfs | grep -q "finobt=1" && _scratch_mkfs -m "finobt=0" >/dev/null 2>&1
> > +
> > +# Get the amount of free inodes from the AGI 0, so we can fill up the freecount
> > +# structure.
> > +freecount=`_scratch_xfs_db -c "agi 0" -c "p freecount" | cut -d' ' -f 3`
> > +
> > +_scratch_mount
> > +
> > +# At the end of filesystem's initialization, AG 0 will have $freecount free
> > +# inodes in the agi->freecount, create $freecount extra dummy files to fill it.
> > +for i in `seq 1 $freecount`; do
> > + touch $SCRATCH_MNT/dummy_file$i
> > +done
> > +
> > +_scratch_unmount >/dev/null 2>&1
> > +
> > +# agi->freecount is 0 here, corrupt it to show extra free inodes
> > +_scratch_xfs_db -x -c "agi 0" -c "write freecount 10" $SCRATCH_DEV >> $seqres.full 2>&1
> > +
> > +_scratch_mount
> > +
> > +# Lock up a buggy kernel
> > +touch $SCRATCH_MNT/lockupfile >> $seqres.full 2>&1
> > +
> > +# If we reach this point, the filesystem is fixed
> > +echo "Silence is golden"
> > +status=0
> > +exit
> > diff --git a/tests/xfs/057.out b/tests/xfs/057.out
> > new file mode 100644
> > index 00000000..185023c7
> > --- /dev/null
> > +++ b/tests/xfs/057.out
> > @@ -0,0 +1,2 @@
> > +QA output created by 057
> > +Silence is golden
> > diff --git a/tests/xfs/group b/tests/xfs/group
> > index cf876a29..37e4e641 100644
> > --- a/tests/xfs/group
> > +++ b/tests/xfs/group
> > @@ -54,6 +54,7 @@
> > 054 auto quick
> > 055 dump ioctl remote tape
> > 056 dump ioctl auto quick
> > +057 auto quick fuzzers dangerous
> > 059 dump ioctl auto quick
> > 060 dump ioctl auto quick
> > 061 dump ioctl auto quick
> > --
> > 2.13.5
> >
> > --
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--
Carlos
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