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author | Qu Wenruo <wqu@suse.com> | 2024-01-28 07:14:17 +1030 |
---|---|---|
committer | Zorro Lang <zlang@kernel.org> | 2024-02-09 13:27:17 +0800 |
commit | 52c6d0f30ae5d087baff79a270f33144effd02e1 (patch) | |
tree | ec80112e5c3be644a1b572bbe2b187f0ff9ed331 | |
parent | 7e1ca29d30389f385086f7be2c6547d05b208afd (diff) | |
download | xfstests-dev-52c6d0f30ae5d087baff79a270f33144effd02e1.tar.gz |
btrfs: verify the read behavior of compressed inline extent
[BUG]
There is a report about reading a zstd compressed inline file extent
would lead to either a VM_BUG_ON() crash, or lead to incorrect file
content.
[CAUSE]
The root cause is a incorrect memcpy_to_page() call, which uses
incorrect page offset, and can lead to either the VM_BUG_ON() as we may
write beyond the page boundary, or writes into the incorrect offset of
the page.
[TEST CASE]
The test case would:
- Mount with the specified compress algorithm
- Create a 4K file
- Verify the 4K file is all inlined and compressed
- Verify the content of the initial write
- Cycle mount to drop all the page cache
- Verify the content of the file again
- Unmount and fsck the fs
This workload would be applied to all supported compression algorithms.
And it can catch the problem correctly by triggering VM_BUG_ON(), as our
workload would result decompressed extent size to be 4K, and would
trigger the VM_BUG_ON() 100%.
And with the revert or the new fix, the test case can pass safely.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>
-rwxr-xr-x | tests/btrfs/310 | 83 | ||||
-rw-r--r-- | tests/btrfs/310.out | 2 |
2 files changed, 85 insertions, 0 deletions
diff --git a/tests/btrfs/310 b/tests/btrfs/310 new file mode 100755 index 0000000000..507485a4e5 --- /dev/null +++ b/tests/btrfs/310 @@ -0,0 +1,83 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2024 SUSE Linux Products GmbH. All Rights Reserved. +# +# FS QA Test 310 +# +# Make sure reading on an compressed inline extent is behaving correctly +# +. ./common/preamble +_begin_fstest auto quick compress + +# Import common functions. +# . ./common/filter + +# real QA test starts here + +# Modify as appropriate. +_supported_fs btrfs +_require_scratch + +# This test require inlined compressed extents creation, and all the writes +# are designed for 4K sector size. +_require_btrfs_inline_extents_creation +_require_btrfs_support_sectorsize 4096 + +_fixed_by_kernel_commit e01a83e12604 \ + "Revert \"btrfs: zstd: fix and simplify the inline extent decompression\"" + +# The correct md5 for the correct 4K file filled with "0xcd" +md5sum_correct="5fed275e7617a806f94c173746a2a723" + +workload() +{ + local algo="$1" + + echo "=== Testing compression algorithm ${algo} ===" >> $seqres.full + _scratch_mkfs >> $seqres.full + _scratch_mount -o compress=${algo} + + _pwrite_byte 0xcd 0 4k "$SCRATCH_MNT/inline_file" > /dev/null + result=$(_md5_checksum "$SCRATCH_MNT/inline_file") + echo "after initial write, md5sum=${result}" >> $seqres.full + if [ "$result" != "$md5sum_correct" ]; then + _fail "initial write results incorrect content for \"$algo\"" + fi + # Writeback data to get correct fiemap result, or we got FIEMAP_DEALLOC + # without compression/inline flags. + sync + + $XFS_IO_PROG -c "fiemap -v" $SCRATCH_MNT/inline_file | tail -n 1 > $tmp.fiemap + cat $tmp.fiemap >> $seqres.full + # Make sure we got an inlined compressed file extent. + # 0x200 means inlined, 0x100 means not block aligned, 0x8 means encoded + # (compressed in this case), and 0x1 means the last extent. + if ! grep -q "0x309" $tmp.fiemap; then + rm -f -- $tmp.fiemap + _notrun "No compressed inline extent created, maybe subpage?" + fi + rm -f -- $tmp.fiemap + + # Unmount to clear the page cache. + _scratch_cycle_mount + + # For v6.8-rc1 without the revert or the newer fix, this would + # lead to VM_BUG_ON() thus crash + result=$(_md5_checksum "$SCRATCH_MNT/inline_file") + echo "after cycle mount, md5sum=${result}" >> $seqres.full + if [ "$result" != "$md5sum_correct" ]; then + _fail "read for compressed inline extent failed for \"$algo\"" + fi + _scratch_unmount + _check_scratch_fs +} + +algo_list=($(_btrfs_compression_algos)) +for algo in ${algo_list[@]}; do + workload $algo +done + +echo "Silence is golden" + +status=0 +exit diff --git a/tests/btrfs/310.out b/tests/btrfs/310.out new file mode 100644 index 0000000000..7b9eaf78a0 --- /dev/null +++ b/tests/btrfs/310.out @@ -0,0 +1,2 @@ +QA output created by 310 +Silence is golden |