| #! /bin/bash |
| # FS QA Test No. 057 |
| # |
| # This test is motivated by an fsync issue discovered in btrfs. |
| # The issue was that we could lose file data, that was previously fsync'ed |
| # successfully, if we end up adding a hard link to our inode and then persist |
| # the fsync log later via an fsync of other inode for example. |
| # |
| # The btrfs issue was fixed by the following linux kernel patch: |
| # |
| # Btrfs: fix fsync data loss after adding hard link to inode |
| # |
| #----------------------------------------------------------------------- |
| # Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved. |
| # Author: Filipe Manana <fdmanana@suse.com> |
| # |
| # 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! |
| |
| _cleanup() |
| { |
| _cleanup_flakey |
| rm -f $tmp.* |
| } |
| trap "_cleanup; exit \$status" 0 1 2 3 15 |
| |
| # get standard environment, filters and checks |
| . ./common/rc |
| . ./common/filter |
| . ./common/dmflakey |
| |
| # real QA test starts here |
| _supported_fs generic |
| _supported_os Linux |
| _require_scratch |
| _require_dm_target flakey |
| |
| rm -f $seqres.full |
| |
| _scratch_mkfs >> $seqres.full 2>&1 |
| _require_metadata_journaling $SCRATCH_DEV |
| _init_flakey |
| _mount_flakey |
| |
| # Create our test file with some data. |
| $XFS_IO_PROG -f -c "pwrite -S 0xaa -b 8K 0 8K" \ |
| $SCRATCH_MNT/foo | _filter_xfs_io |
| |
| # Make sure the file is durably persisted. |
| sync |
| |
| # Append some data to our file, to increase its size. |
| $XFS_IO_PROG -f -c "pwrite -S 0xcc -b 4K 8K 4K" \ |
| $SCRATCH_MNT/foo | _filter_xfs_io |
| |
| # Fsync the file, so from this point on if a crash/power failure happens, our |
| # new data is guaranteed to be there next time the fs is mounted. |
| $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo |
| |
| # Add one hard link to our file. This made btrfs write into the in memory fsync |
| # log a special inode with generation 0 and an i_size of 0 too. Note that this |
| # didn't update the inode in the fsync log on disk. |
| ln $SCRATCH_MNT/foo $SCRATCH_MNT/foo_link |
| |
| # Now make sure the in memory fsync log is durably persisted. |
| # Creating and fsync'ing another file will do it. |
| touch $SCRATCH_MNT/bar |
| $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/bar |
| |
| # As expected, before the crash/power failure, we should be able to read the |
| # 12Kb of file data. |
| echo "File content before:" |
| od -t x1 $SCRATCH_MNT/foo |
| |
| _flakey_drop_and_remount |
| |
| # After mounting the fs again, the fsync log was replayed. |
| # The btrfs fsync log replay code didn't update the i_size of the persisted |
| # inode because the inode item in the log had a special generation with a |
| # value of 0 (and it couldn't know the correct i_size, since that inode item |
| # had a 0 i_size too). This made the last 4Kb of file data inaccessible and |
| # effectively lost. |
| echo "File content after:" |
| od -t x1 $SCRATCH_MNT/foo |
| |
| status=0 |
| exit |