On Tue, Jul 14, 2015 at 04:37:14PM +0100, fdmanana@xxxxxxxxxx wrote:
> From: Filipe Manana <fdmanana@xxxxxxxx>
>
> This tests that we can not clone an inline extent into a non-zero file
> offset. Inline extents at non-zero offsets is something btrfs is not
> prepared for and results in all sorts of corruption and crashes on
> future IO operations, such as the following BUG_ON() triggered by the
> last write operation done by this test:
>
> [152154.035903] ------------[ cut here ]------------
> [152154.036424] kernel BUG at mm/page-writeback.c:2286!
> [152154.036424] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
> (...)
> [152154.036424] RIP: 0010:[<ffffffff8111a9d5>] [<ffffffff8111a9d5>] clear_page_dirty_for_io+0x1e/0x90
> (...)
> [152154.036424] Call Trace:
> [152154.036424] [<ffffffffa04e97c1>] lock_and_cleanup_extent_if_need+0x147/0x18d [btrfs]
> [152154.036424] [<ffffffffa04ea82c>] __btrfs_buffered_write+0x245/0x4c8 [btrfs]
> [152154.036424] [<ffffffffa04ed14b>] ? btrfs_file_write_iter+0x150/0x3e0 [btrfs]
> [152154.036424] [<ffffffffa04ed15a>] ? btrfs_file_write_iter+0x15f/0x3e0 [btrfs]
> [152154.036424] [<ffffffffa04ed2c7>] btrfs_file_write_iter+0x2cc/0x3e0 [btrfs]
> [152154.036424] [<ffffffff81165a4a>] __vfs_write+0x7c/0xa5
> [152154.036424] [<ffffffff81165f89>] vfs_write+0xa0/0xe4
> [152154.036424] [<ffffffff81166855>] SyS_pwrite64+0x64/0x82
> [152154.036424] [<ffffffff81465197>] system_call_fastpath+0x12/0x6f
> (...)
> [152154.242621] ---[ end trace e3d3376b23a57041 ]---
>
> This issue is addressed by the following linux kernel patch for btrfs:
> "Btrfs: fix file corruption after cloning inline extents".
>
> Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: Omar Sandoval <osandov@xxxxxx>
Tested that it passes on 4.2-rc3 and fails with the specified commit
reverted.
> ---
> tests/btrfs/096 | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> tests/btrfs/096.out | 12 ++++++++
> tests/btrfs/group | 1 +
> 3 files changed, 93 insertions(+)
> create mode 100755 tests/btrfs/096
> create mode 100644 tests/btrfs/096.out
>
> diff --git a/tests/btrfs/096 b/tests/btrfs/096
> new file mode 100755
> index 0000000..f5b3a7f
> --- /dev/null
> +++ b/tests/btrfs/096
> @@ -0,0 +1,80 @@
> +#! /bin/bash
> +# FSQA Test No. 096
> +#
> +# Test that we can not clone an inline extent into a non-zero file offset.
> +#
> +#-----------------------------------------------------------------------
> +#
> +# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
> +# Author: Filipe Manana <fdmanana@xxxxxxxx>
> +#
> +# 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"
> +tmp=/tmp/$$
> +status=1 # failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> + rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +
> +# real QA test starts here
> +_need_to_be_root
> +_supported_fs btrfs
> +_supported_os Linux
> +_require_scratch
> +_require_cloner
> +
> +rm -f $seqres.full
> +
> +_scratch_mkfs >>$seqres.full 2>&1
> +_scratch_mount
> +
> +# Create our test files. File foo has the same 2K of data at offset 4K as file
> +# bar has at its offset 0.
> +$XFS_IO_PROG -f -s -c "pwrite -S 0xaa 0 4K" \
> + -c "pwrite -S 0xbb 4k 2K" \
> + -c "pwrite -S 0xcc 8K 4K" \
> + $SCRATCH_MNT/foo | _filter_xfs_io
> +
> +# File bar consists of a single inline extent (2K size).
> +$XFS_IO_PROG -f -s -c "pwrite -S 0xbb 0 2K" \
> + $SCRATCH_MNT/bar | _filter_xfs_io
> +
> +# Now call the clone ioctl to clone the extent of file bar into file foo at its
> +# offset 4K. This made file foo have an inline extent at offset 4K, something
> +# which the btrfs code can not deal with in future IO operations because all
> +# inline extents are supposed to start at an offset of 0, resulting in all sorts
> +# of chaos.
> +# So here we validate that the clone ioctl returns an EOPNOTSUPP, which is what
> +# it returns for other cases dealing with inlined extents.
> +$CLONER_PROG -s 0 -d $((4 * 1024)) -l $((2 * 1024)) \
> + $SCRATCH_MNT/bar $SCRATCH_MNT/foo
> +
> +# Because of the inline extent at offset 4K, the following write made the kernel
> +# crash with a BUG_ON().
> +$XFS_IO_PROG -c "pwrite -S 0xdd 6K 2K" $SCRATCH_MNT/foo | _filter_xfs_io
> +
> +status=0
> +exit
> diff --git a/tests/btrfs/096.out b/tests/btrfs/096.out
> new file mode 100644
> index 0000000..235198d
> --- /dev/null
> +++ b/tests/btrfs/096.out
> @@ -0,0 +1,12 @@
> +QA output created by 096
> +wrote 4096/4096 bytes at offset 0
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +wrote 2048/2048 bytes at offset 4096
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +wrote 4096/4096 bytes at offset 8192
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +wrote 2048/2048 bytes at offset 0
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +clone failed: Operation not supported
> +wrote 2048/2048 bytes at offset 6144
> +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 79feea9..6ff5f3d 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -97,3 +97,4 @@
> 093 auto quick clone
> 094 auto quick send
> 095 auto quick metadata
> +096 auto quick clone
> --
> 2.1.3
>
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--
Omar
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