mirror of
https://github.com/linux-apfs/apfstests.git
synced 2026-05-01 15:01:44 -07:00
Zorro Lang
a8b4891d0f
We met a kernel assertion failure recently as below: XFS: Assertion failed: tp->t_blk_res_used <= tp->t_blk_res, file: fs/xfs/xfs_trans.c, line: 309 Eric Sandeen digged into it and find a good reproducer. The problem comes when the several IO vectors are copied in, and it runs into page faults, which stops the copy before all vectors are copied. XFS sees this as a failed/short write, and so tries to unmap the blocks & truncate away the pages in xfs_vm_write_end. generic_perform_write is looping, and comes back around for the other iovecs, but the page is still there, the buffer head is still mapped, and so a new delalloc block isn't allocated - and ends up being allocated at writeback time, despite the fact that we "should" have accounted for it all at delalloc write time, and trips the assert. Signed-off-by: Zorro Lang <zlang@redhat.com> Reviewed-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Eryu Guan <eguan@redhat.com>
62 lines
1.8 KiB
Bash
Executable File
62 lines
1.8 KiB
Bash
Executable File
#! /bin/bash
|
|
# FS QA Test 443
|
|
#
|
|
# Takes page fault while writev is iterating over the vectors in the IOV
|
|
#
|
|
#-----------------------------------------------------------------------
|
|
# 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
|
|
_supported_fs generic
|
|
_supported_os Linux
|
|
_require_test
|
|
_require_test_program "writev_on_pagefault"
|
|
|
|
# This program use several vectors for writev(), the kernel goes over them
|
|
# one at a time, copying them from userspace, getting the user data ready
|
|
# for IO. If it takes a page fault while iterating over the vectors in the
|
|
# IOV, it stops, and sends what it got so far. We try to find a bug at this
|
|
# moment.
|
|
$here/src/writev_on_pagefault $TEST_DIR/testfile.$seq
|
|
|
|
# success, all done
|
|
status=0
|
|
exit
|