Re: [PATCH] fstests: add a another gap extent testcase for btrfs

[Eryu Guan <guaneryu@gmail.com>]

On Thu, Feb 20, 2020 at 04:24:37PM +0000, Filipe Manana wrote:
> On Thu, Feb 20, 2020 at 2:39 PM Josef Bacik <josef@toxicpanda.com> wrote:
> >
> > This is a testcase for a corner that I missed when trying to fix gap
> > extents for btrfs.  We would end up with gaps if we hole punched past
> > isize and then extended past the gap in a specific way.  This is a
> > simple reproducer to show the problem, and has been properly fixed by my
> > patches now.
> >
> > Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> > ---
> >  tests/btrfs/204     | 85 +++++++++++++++++++++++++++++++++++++++++++++
> >  tests/btrfs/204.out |  5 +++
> >  tests/btrfs/group   |  1 +
> >  3 files changed, 91 insertions(+)
> >  create mode 100755 tests/btrfs/204
> >  create mode 100644 tests/btrfs/204.out
> >
> > diff --git a/tests/btrfs/204 b/tests/btrfs/204
> > new file mode 100755
> > index 00000000..0d5c4bed
> > --- /dev/null
> > +++ b/tests/btrfs/204
> > @@ -0,0 +1,85 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (c) 2020 Facebook.  All Rights Reserved.
> > +#
> > +# FS QA Test 204
> > +#
> > +# Validate that without no-holes we do not get a i_size that is after a gap in
> > +# the file extents on disk when punching a hole past i_size.  This is fixed by
> > +# the following patches
> > +#
> > +#      btrfs: use the file extent tree infrastructure
> > +#      btrfs: replace all uses of btrfs_ordered_update_i_size
> > +#
> > +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
> > +. ./common/dmlogwrites
> > +
> > +# remove previous $seqres.full before test
> > +rm -f $seqres.full
> > +
> > +# real QA test starts here
> > +
> > +# Modify as appropriate.
> > +_supported_fs generic

I also changed 'generic' to 'btrfs'

> > +_supported_os Linux
> > +_require_test
> > +_require_scratch
> > +_require_log_writes
> 
> _require_xfs_io_command "falloc" "-k"
> _require_xfs_io_command "fpunch"

Added.

> 
> > +
> > +_log_writes_init $SCRATCH_DEV
> > +_log_writes_mkfs "-O ^no-holes" >> $seqres.full 2>&1
> > +
> > +# There's not a straightforward way to commit the transaction without also
> > +# flushing dirty pages, so shorten the commit interval to 1 so we're sure to get
> > +# a commit with our broken file
> > +_log_writes_mount -o commit=1
> > +
> > +# This creates a gap extent because fpunch doesn't insert hole extents past
> > +# i_size
> > +xfs_io -f -c "falloc -k 4k 8k" $SCRATCH_MNT/file
> > +xfs_io -f -c "fpunch 4k 4k" $SCRATCH_MNT/file
> > +
> > +# The pwrite extends the i_size to cover the gap extent, and then the truncate
> > +# sets the disk_i_size to 12k because it assumes everything was a-ok.
> > +xfs_io -f -c "pwrite 0 4k" $SCRATCH_MNT/file | _filter_xfs_io
> > +xfs_io -f -c "pwrite 0 8k" $SCRATCH_MNT/file | _filter_xfs_io
> > +xfs_io -f -c "truncate 12k" $SCRATCH_MNT/file

Changed all 'xfs_io' to '$XFS_IO_PROG'.

> > +
> > +# Wait for a transaction commit
> > +sleep 2
> > +
> > +_log_writes_unmount
> > +_log_writes_remove
> > +
> > +cur=$(_log_writes_find_next_fua 0)
> > +echo "cur=$cur" >> $seqres.full
> > +while [ ! -z "$cur" ]; do
> > +       _log_writes_replay_log_range $cur $SCRATCH_DEV >> $seqres.full
> > +
> > +       # We only care about the fs consistency, so just run fsck, we don't have
> > +       # to mount the fs to validate it
> > +       _check_scratch_fs
> > +
> > +       cur=$(_log_writes_find_next_fua $(($cur + 1)))
> > +done
> > +
> > +# success, all done
> > +status=0
> > +exit
> > diff --git a/tests/btrfs/204.out b/tests/btrfs/204.out
> > new file mode 100644
> > index 00000000..44c7c8ae
> > --- /dev/null
> > +++ b/tests/btrfs/204.out
> > @@ -0,0 +1,5 @@
> > +QA output created by 204
> > +wrote 4096/4096 bytes at offset 0
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +wrote 8192/8192 bytes at offset 0
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > diff --git a/tests/btrfs/group b/tests/btrfs/group
> > index 6acc6426..7a840177 100644
> > --- a/tests/btrfs/group
> > +++ b/tests/btrfs/group
> > @@ -206,3 +206,4 @@
> >  201 auto quick punch log
> >  202 auto quick subvol snapshot
> >  203 auto quick send clone
> > +204 auto quick log replay
> 
> "prealloc" and "punch" groups as well.

Added.

> 
> Since this just tests another variant of the same problem, maybe it
> could be added to btrfs/172, since that test is very recent and you
> authored it as well.
> Anyway, I don't have a strong preference.
> 
> The test itself looks good to me, and with the _require_xfs_io_command
> thing added and the groups (maybe Eryu can add these at commit time):
> 
> Reviewed-by: Filipe Manana <fdmanana@suse.com>

Thanks for the review!

Eryu

> 
> 
> > --
> > 2.24.1
> >
> 
> 
> -- 
> Filipe David Manana,
> 
> “Whether you think you can, or you think you can't — you're right.”