2 # SPDX-License-Identifier: GPL-2.0
3 # Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
5 # FS QA Test No. btrfs/097
7 # Test that an incremental send works after a file gets one of its extents
8 # cloned/deduplicated into lower file offsets.
11 seqres=$RESULT_DIR/$seq
12 echo "QA output created by $seq"
15 status=1 # failure is the default!
16 trap "_cleanup; exit \$status" 0 1 2 3 15
20 rm -fr $send_files_dir
24 # get standard environment, filters and checks
28 # real QA test starts here
33 send_files_dir=$TEST_DIR/btrfs-test-$seq
36 rm -fr $send_files_dir
39 _scratch_mkfs >>$seqres.full 2>&1
42 BLOCK_SIZE=$(_get_block_size $SCRATCH_MNT)
44 # Create our test file with a single extent of 16 blocks starting at a file
45 # offset mapped by 32nd block.
46 $XFS_IO_PROG -f -c "pwrite -S 0xaa $((32 * $BLOCK_SIZE)) $((16 * $BLOCK_SIZE))" \
47 $SCRATCH_MNT/foo | _filter_xfs_io_blocks_modified
49 _run_btrfs_util_prog subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap1
51 # Now clone parts of the original extent into lower offsets of the file.
53 # The first clone operation adds a file extent item to file offset 0 that points
54 # to our initial extent with a data offset of 4 blocks. The corresponding data back
55 # reference in the extent tree has a large value for the 'offset' field, which is
56 # the result of file_offset - data_offset = 0 - (file offset of 4th block). For
57 # example in case of 4k block size, it will be 0 - 16k = 18446744073709535232.
59 # The second clone operation adds a file extent item to file offset mapped by
60 # 4th block that points to our initial extent with a data offset of 12
61 # blocks. The corresponding data back reference in the extent tree has a large
62 # value for the 'offset' field, which is the result of file_offset - data_offset
63 # = (file offset of 4th block) - (file offset of 12th block). For example in
64 # case of 4k block size, it will be 16K - 48K = 18446744073709518848.
66 # Those large back reference offsets (result of unsigned arithmetic underflow)
67 # confused the back reference walking code (used by an incremental send and
68 # the multiple inspect-internal ioctls) and made it miss the back references,
69 # which for the case of an incremental send it made it fail with -EIO and print
70 # a message like the following to dmesg:
72 # "BTRFS error (device sdc): did not find backref in send_root. inode=257, \
73 # offset=0, disk_byte=12845056 found extent=12845056"
75 $CLONER_PROG -s $(((32 + 4) * $BLOCK_SIZE)) -d 0 -l $((4 * $BLOCK_SIZE)) \
76 $SCRATCH_MNT/foo $SCRATCH_MNT/foo
77 $CLONER_PROG -s $(((32 + 12) * $BLOCK_SIZE)) -d $((4 * $BLOCK_SIZE)) \
78 -l $((4 * $BLOCK_SIZE)) $SCRATCH_MNT/foo $SCRATCH_MNT/foo
80 _run_btrfs_util_prog subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap2
82 _run_btrfs_util_prog send -f $send_files_dir/1.snap $SCRATCH_MNT/mysnap1
83 _run_btrfs_util_prog send -p $SCRATCH_MNT/mysnap1 -f $send_files_dir/2.snap \
86 echo "File contents in the original filesystem:"
87 od -t x1 $SCRATCH_MNT/mysnap2/foo | _filter_od
89 # Now recreate the filesystem by receiving both send streams and verify we get
90 # the same file contents that the original filesystem had.
92 _scratch_mkfs >>$seqres.full 2>&1
95 _run_btrfs_util_prog receive -f $send_files_dir/1.snap $SCRATCH_MNT
96 _run_btrfs_util_prog receive -f $send_files_dir/2.snap $SCRATCH_MNT
98 echo "File contents in the new filesystem:"
99 od -t x1 $SCRATCH_MNT/mysnap2/foo | _filter_od