On Tue, Jun 6, 2023 at 12:03 PM Qu Wenruo <wqu@xxxxxxxx> wrote:
>
> There is a regression on btrfs read-only scrub behavior.
>
> The commit e02ee89baa66 ("btrfs: scrub: switch scrub_simple_mirror() to
> scrub_stripe infrastructure") makes btrfs scrub to ignore the read-only
> flag completely, causing scrub to always fix the corruption.
>
> This test case would create an fs with repairable corruptions, then run
> a read-only scrub, and finally to make sure the corruption is not
> repaired.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
Looks good, thanks.
> ---
> Changelog:
> v2:
> - Add _fixed_by_kernel_commit
>
> - Reduce the golden output
> Instead of the first 512 bytes, the first 16 bytes are more than
> enough.
>
> - Better golden output
> Add two more steps explaining what the test is doing.
>
> - Output the offset for the file operation inside the fs
> The offset is fixed, no need to use _filter_xfs_io_offset.
>
> - Remove the confusing comments on common/filter
> ---
> tests/btrfs/288 | 70 +++++++++++++++++++++++++++++++++++++++++++++
> tests/btrfs/288.out | 9 ++++++
> 2 files changed, 79 insertions(+)
> create mode 100755 tests/btrfs/288
> create mode 100644 tests/btrfs/288.out
>
> diff --git a/tests/btrfs/288 b/tests/btrfs/288
> new file mode 100755
> index 00000000..52245895
> --- /dev/null
> +++ b/tests/btrfs/288
> @@ -0,0 +1,70 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (C) 2023 SUSE Linux Products GmbH. All Rights Reserved.
> +#
> +# FS QA Test 288
> +#
> +# Make sure btrfs-scrub respects the read-only flag.
> +#
> +. ./common/preamble
> +_begin_fstest auto repair quick volume scrub
> +
> +. ./common/filter
> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs btrfs
> +_require_scratch_dev_pool 2
> +
> +
> +_require_odirect
> +# Overwriting data is forbidden on a zoned block device
> +_require_non_zoned_device "${SCRATCH_DEV}"
> +
> +_fixed_by_kernel_commit xxxxxxxxxxxx \
> + "btrfs: scrub: respect the read-only flag during repair"
> +
> +_scratch_dev_pool_get 2
> +
> +# Step 1, create a raid btrfs with one 128K file
> +echo "step 1......mkfs.btrfs"
> +_scratch_pool_mkfs -d raid1 -b 1G >> $seqres.full 2>&1
> +_scratch_mount
> +
> +$XFS_IO_PROG -f -d -c "pwrite -S 0xaa -b 128K 0 128K" "$SCRATCH_MNT/foobar" |\
> + _filter_xfs_io
> +
> +# Step 2, corrupt one mirror so we can still repair the fs.
> +echo "step 2......corrupt one mirror"
> +# ensure btrfs-map-logical sees the tree updates
> +sync
> +
> +logical=$(_btrfs_get_first_logical $SCRATCH_MNT/foobar)
> +
> +physical1=$(_btrfs_get_physical ${logical} 1)
> +devpath1=$(_btrfs_get_device_path ${logical} 1)
> +
> +_scratch_unmount
> +
> +echo " corrupt stripe #1, devpath $devpath1 physical $physical1" \
> + >> $seqres.full
> +$XFS_IO_PROG -d -c "pwrite -S 0xf1 -b 64K $physical1 64K" $devpath1 \
> + > /dev/null
> +
> +# Step 3, do a read-only scrub, which should not fix the corruption.
> +echo "step 3......do a read-only scrub"
> +_scratch_mount -o ro
> +$BTRFS_UTIL_PROG scrub start -BRrd $SCRATCH_MNT >> $seqres.full 2>&1
> +_scratch_unmount
> +
> +# Step 4, make sure the corruption is still there
> +echo "step 4......verify the corruption is not repaired"
> +echo " the first 16 bytes of the extent at mirror 1:"
> +$XFS_IO_PROG -c "pread -qv $physical1 16" $devpath1 |\
> + _filter_xfs_io_offset
> +
> +_scratch_dev_pool_put
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/btrfs/288.out b/tests/btrfs/288.out
> new file mode 100644
> index 00000000..452bdc67
> --- /dev/null
> +++ b/tests/btrfs/288.out
> @@ -0,0 +1,9 @@
> +QA output created by 288
> +step 1......mkfs.btrfs
> +wrote 131072/131072 bytes at offset 0
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +step 2......corrupt one mirror
> +step 3......do a read-only scrub
> +step 4......verify the corruption is not repaired
> + the first 16 bytes of the extent at mirror 1:
> +XXXXXXXX: f1 f1 f1 f1 f1 f1 f1 f1 f1 f1 f1 f1 f1 f1 f1 f1 ................
> --
> 2.39.0
>
