Re: [PATCH 5/8] Fix btrfs/097 to work on non-4k block sized filesystems

Filipe Manana
2015-12-10T17:27:50Z

On Mon, Nov 30, 2015 at 10:17 AM, Chandan Rajendra
<chandan@linux.vnet.ibm.com> wrote:
> This commit makes use of the new _filter_xfs_io_blocks_modified filtering
> function to print information in terms of file blocks rather than file
> offset.
>
> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>

Thanks!

> ---
> tests/btrfs/097 | 41 ++++++++++++++++++++++++-----------------
> tests/btrfs/097.out | 23 +++++++++++++++++------
> 2 files changed, 41 insertions(+), 23 deletions(-)
>
> diff --git a/tests/btrfs/097 b/tests/btrfs/097
> index d9138ea..d1cfff1 100755
> --- a/tests/btrfs/097
> +++ b/tests/btrfs/097
> @@ -57,22 +57,29 @@ mkdir $send_files_dir
> _scratch_mkfs >>$seqres.full 2>&1
> _scratch_mount
>
> -# Create our test file with a single extent of 64K starting at file offset 128K.
> -$XFS_IO_PROG -f -c "pwrite -S 0xaa 128K 64K" $SCRATCH_MNT/foo | _filter_xfs_io
> +BLOCK_SIZE=$(get_block_size $SCRATCH_MNT)
> +
> +# Create our test file with a single extent of 16 blocks starting at a file
> +# offset mapped by 32nd block.
> +$XFS_IO_PROG -f -c "pwrite -S 0xaa $((32 * $BLOCK_SIZE)) $((16 * $BLOCK_SIZE))" \
> + $SCRATCH_MNT/foo | _filter_xfs_io_blocks_modified
>
> _run_btrfs_util_prog subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap1
>
> # Now clone parts of the original extent into lower offsets of the file.
> #
> # The first clone operation adds a file extent item to file offset 0 that points
> -# to our initial extent with a data offset of 16K. The corresponding data back
> -# reference in the extent tree has an offset of 18446744073709535232, which is
> -# the result of file_offset - data_offset = 0 - 16K.
> -#
> -# The second clone operation adds a file extent item to file offset 16K that
> -# points to our initial extent with a data offset of 48K. The corresponding data
> -# back reference in the extent tree has an offset of 18446744073709518848, which
> -# is the result of file_offset - data_offset = 16K - 48K.
> +# to our initial extent with a data offset of 4 blocks. The corresponding data back
> +# reference in the extent tree has a large value for the 'offset' field, which is
> +# the result of file_offset - data_offset = 0 - (file offset of 4th block). For
> +# example in case of 4k block size, it will be 0 - 16k = 18446744073709535232.
> +
> +# The second clone operation adds a file extent item to file offset mapped by
> +# 4th block that points to our initial extent with a data offset of 12
> +# blocks. The corresponding data back reference in the extent tree has a large
> +# value for the 'offset' field, which is the result of file_offset - data_offset
> +# = (file offset of 4th block) - (file offset of 12th block). For example in
> +# case of 4k block size, it will be 16K - 48K = 18446744073709518848.
> #
> # Those large back reference offsets (result of unsigned arithmetic underflow)
> # confused the back reference walking code (used by an incremental send and
> @@ -83,10 +90,10 @@ _run_btrfs_util_prog subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap1
> # "BTRFS error (device sdc): did not find backref in send_root. inode=257, \
> # offset=0, disk_byte=12845056 found extent=12845056"
> #
> -$CLONER_PROG -s $(((128 + 16) * 1024)) -d 0 -l $((16 * 1024)) \
> - $SCRATCH_MNT/foo $SCRATCH_MNT/foo
> -$CLONER_PROG -s $(((128 + 48) * 1024)) -d $((16 * 1024)) -l $((16 * 1024)) \
> +$CLONER_PROG -s $(((32 + 4) * $BLOCK_SIZE)) -d 0 -l $((4 * $BLOCK_SIZE)) \
> $SCRATCH_MNT/foo $SCRATCH_MNT/foo
> +$CLONER_PROG -s $(((32 + 12) * $BLOCK_SIZE)) -d $((4 * $BLOCK_SIZE)) \
> + -l $((4 * $BLOCK_SIZE)) $SCRATCH_MNT/foo $SCRATCH_MNT/foo
>
> _run_btrfs_util_prog subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap2
>
> @@ -94,8 +101,8 @@ _run_btrfs_util_prog send $SCRATCH_MNT/mysnap1 -f $send_files_dir/1.snap
> _run_btrfs_util_prog send -p $SCRATCH_MNT/mysnap1 $SCRATCH_MNT/mysnap2 \
> -f $send_files_dir/2.snap
>
> -echo "File digest in the original filesystem:"
> -md5sum $SCRATCH_MNT/mysnap2/foo | _filter_scratch
> +echo "File contents in the original filesystem:"
> +od -t x1 $SCRATCH_MNT/mysnap2/foo | _filter_od
>
> # Now recreate the filesystem by receiving both send streams and verify we get
> # the same file contents that the original filesystem had.
> @@ -106,8 +113,8 @@ _scratch_mount
> _run_btrfs_util_prog receive $SCRATCH_MNT -f $send_files_dir/1.snap
> _run_btrfs_util_prog receive $SCRATCH_MNT -f $send_files_dir/2.snap
>
> -echo "File digest in the new filesystem:"
> -md5sum $SCRATCH_MNT/mysnap2/foo | _filter_scratch
> +echo "File contents in the new filesystem:"
> +od -t x1 $SCRATCH_MNT/mysnap2/foo | _filter_od
>
> status=0
> exit
> diff --git a/tests/btrfs/097.out b/tests/btrfs/097.out
> index 5e87eb2..aa9e549 100644
> --- a/tests/btrfs/097.out
> +++ b/tests/btrfs/097.out
> @@ -1,7 +1,18 @@
> QA output created by 097
> -wrote 65536/65536 bytes at offset 131072
> -XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> -File digest in the original filesystem:
> -6c6079335cff141b8a31233ead04cbff SCRATCH_MNT/mysnap2/foo
> -File digest in the new filesystem:
> -6c6079335cff141b8a31233ead04cbff SCRATCH_MNT/mysnap2/foo
> +Blocks modified: [32 - 47]
> +File contents in the original filesystem:
> +0 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> +*
> +10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +40 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> +*
> +60
> +File contents in the new filesystem:
> +0 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> +*
> +10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +40 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> +*
> +60
> --
> 2.1.0
>

--
Filipe David Manana,

"Reasonable men adapt themselves to the world.
Unreasonable men adapt the world to themselves.
That's why all progress depends on unreasonable men."