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https://github.com/linux-apfs/apfstests.git
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Brian Foster
9490edd677
XFS has a bug where directory readahead completions can occur after unmount. This can lead to a crash or panic because metadata read verification attempts to access core XFS data structures (e.g., the log) after they have been freed and certain pointers have been reset. Add a test that triggers directory readahead, delays the readahead I/O and immediately unmounts the filesystem. This test is part of the dangerous group as it will cause kernels affected by the bug to crash. [eguan replaced touch with echo to speedup file creation] Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Eryu Guan <eguan@redhat.com>
92 lines
2.5 KiB
Bash
Executable File
92 lines
2.5 KiB
Bash
Executable File
#! /bin/bash
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# FS QA Test No. 311
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#
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# Test to reproduce an XFS unmount crash due to races with directory readahead.
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# XFS had a bug in which unmount would proceed with a readahead I/O in flight.
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# If the unmount deconstructed the log by the time I/O completion occurs,
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# certain metadata read verifier checks could access invalid memory and cause a
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# panic.
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#
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#-----------------------------------------------------------------------
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# Copyright (c) 2016 Red Hat, Inc. All Rights Reserved.
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#
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU General Public License as
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# published by the Free Software Foundation.
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#
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# This program is distributed in the hope that it would be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write the Free Software Foundation,
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# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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#-----------------------------------------------------------------------
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#
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seq=`basename $0`
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seqres=$RESULT_DIR/$seq
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echo "QA output created by $seq"
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here=`pwd`
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tmp=/tmp/$$
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status=1 # failure is the default!
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trap "_cleanup; exit \$status" 0 1 2 3 15
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_cleanup()
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{
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cd /
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rm -f $tmp.*
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_scratch_unmount > /dev/null 2>&1
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_cleanup_delay > /dev/null 2>&1
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}
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# get standard environment, filters and checks
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. ./common/rc
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. ./common/dmdelay
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# Modify as appropriate.
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_supported_fs xfs
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_supported_os Linux
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_require_scratch
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_require_dm_target delay
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rm -f $seqres.full
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echo "Silence is golden."
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_scratch_mkfs_xfs >> $seqres.full 2>&1
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_init_delay
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_mount_delay
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# insert entries to grow the directory to at least one extent, which is what
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# triggers readahead on dir open
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mkdir $SCRATCH_MNT/dir
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for i in $(seq 0 999); do
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echo > $SCRATCH_MNT/dir/$i
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done
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# remount to clear the buffer cache
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_unmount_delay
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_mount_delay
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# introduce a read I/O delay
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_load_delay_table $DELAY_READ
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# Map the directory and immediately unmount. This should invoke an asynchronous
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# readahead on the first block of the directory. The readahead is delayed by
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# dm-delay. If the unmount doesn't properly wait for the readahead completion,
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# the read verifier can run after core data structures have been freed and lead
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# to a crash/panic.
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$XFS_IO_PROG -c "bmap -v" $SCRATCH_MNT/dir >> $seqres.full 2>&1
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_unmount_delay
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_cleanup_delay
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# success, all done
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status=0
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exit
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