2 # SPDX-License-Identifier: GPL-2.0
3 # Copyright (C) 2019 SUSE Linux Products GmbH. All Rights Reserved.
7 # Test if btrfs discard mount option is trimming adjacent extents across
8 # block groups boundary.
9 # The test case uses loopback device and file used space to detect trimmed
12 # There is a long existing bug that btrfs doesn't discard all space for
13 # above mentioned case.
15 # The fix is: "btrfs: extent-tree: Ensure we trim ranges across block group
19 _begin_fstest auto quick trim
21 # Override the default cleanup function.
25 umount $loop_mnt &> /dev/null
26 _destroy_loop_device $loop_dev &> /dev/null
30 # Import common functions.
33 # real QA test starts here
35 # Modify as appropriate.
38 _require_xfs_io_command "fiemap"
40 # We need less than 2G data write, consider it 2G and double it just in case
41 _require_scratch_size $((4 * 1024 * 1024))
43 loop_file="$SCRATCH_MNT/image"
45 # The margin when checking trimmed size.
47 # The margin is for tree blocks, calculated by
48 # 3 * max_tree_block_size
50 # |- 3 trees get modified (root tree, extent tree, fs tree)
52 # In reality, there should be no margin at all due to the mount options.
53 # But who knows what will happen in later kernels.
54 margin_kb=$(( 3 * 64 ))
55 trimmed_kb=$(( 768 * 1024 )) # 768M
57 _scratch_mkfs >> $seqres.full
60 # Create a sparse file as the loopback target.
61 # 10G size makes sure we have 1G chunk size.
62 truncate -s 10G "$loop_file"
64 _mkfs_dev -d SINGLE "$loop_file"
66 loop_dev=$(_create_loop_device "$loop_file")
67 loop_mnt=$tmp/loop_mnt
71 # Since v1 cache using DATA space, it can break data extent bytenr
74 # As there will be 1.5G data write, generating 1.5M csum.
75 # Disabling datasum could reduce the margin caused by metadata to minimal
78 _mount -o nospace_cache,nodatasum,discard $loop_dev $loop_mnt
80 # Craft the following extent layout:
82 # Bytenr: X-8M X X+512M X+1G X+1G+128M
83 # |//////|//////| |//|
85 # | | | |- file 'tail_padding'
86 # | | |- file 'cross_boundary'
87 # | |- file 'lead_padding2'
88 # |- file 'lead_padding1'
89 # So that all extents of file 'cross_boundary' are all adjacent and crosses the
90 # boundary of BG1 and BG2
91 # File 'lead_padding1' and 'lead_padding2' are all paddings to fill the
93 # File 'tail_padding' is to ensure after deleting file 'cross_boundary' we still
94 # have used extent in BG3, to prevent trimming the whole BG3.
95 # And since BG1 needs exactly 8M to fill, we need to sync write to ensure
97 _pwrite_byte 0xcd 0 8M $loop_mnt/lead_padding1 > /dev/null
100 _pwrite_byte 0xcd 0 512M $loop_mnt/lead_padding2 > /dev/null
102 _pwrite_byte 0xcd 0 $(($trimmed_kb * 1024)) $loop_mnt/cross_boundary \
106 _pwrite_byte 0xcd 0 1M $loop_mnt/tail_padding > /dev/null
109 $XFS_IO_PROG -c "fiemap" $loop_mnt/cross_boundary >> $seqres.full
110 # Ensure all extent are continuous
111 # Btrfs fiemap will merge continuous results, so the output should be only
112 # 2 lines, 1 line for filename, 1 line for a large merged fiemap result.
113 if [ $($XFS_IO_PROG -c "fiemap" $loop_mnt/cross_boundary | wc -l) -ne 2 ]; then
114 _notrun "Non-continuous extent bytenr detected"
117 size1_kb=$(du $loop_file| cut -f1)
119 # Delete the file 'cross_boundary'.
120 # This will delete $trimmed_kb data extents across the chunk boundary.
121 rm -f $loop_mnt/cross_boundary
123 # sync so btrfs will commit transaction and trim the freed extents
126 size2_kb=$(du $loop_file | cut -f1)
128 echo "loopback file size before discard: $size1_kb KiB" >> $seqres.full
129 echo "loopback file size after discard: $size2_kb KiB" >> $seqres.full
130 echo "Expect trimmed size: $trimmed_kb KiB" >> $seqres.full
131 echo "Have trimmed size: $(($size1_kb - $size2_kb)) KiB" >> $seqres.full
133 if [ $(($size2_kb+ $trimmed_kb)) -gt $(($size1_kb + $margin_kb)) -o \
134 $(($size2_kb+ $trimmed_kb)) -lt $(($size1_kb - $margin_kb)) ]; then
135 echo "Btrfs doesn't trim the range correctly"
138 echo "Silence is golden"