Re: [PATCH] btrfs-progs: tests: test mkfs.btrfs fails on small backing size thin provision device

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2018年04月11日 15:03, Su Yue wrote:
> This tests is most similar to xfstests generic/405.
> It calls device mapper to create a thin provision device with small
> backing size and big virtual size. mkfs.btrfs should fail on such
> devices.
> 
> This test should pass after commit e805b143a4fe
> ("btrfs-progs: mkfs: return nozero value on thin provisioned device").
> 
> Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
> ---
>  .../test.sh                                   | 93 +++++++++++++++++++
>  1 file changed, 93 insertions(+)
>  create mode 100755 tests/mkfs-tests/017-small-backing-size-thin-provision-device/test.sh
> 
> diff --git a/tests/mkfs-tests/017-small-backing-size-thin-provision-device/test.sh b/tests/mkfs-tests/017-small-backing-size-thin-provision-device/test.sh
> new file mode 100755
> index 000000000000..f2e044da5d17
> --- /dev/null
> +++ b/tests/mkfs-tests/017-small-backing-size-thin-provision-device/test.sh
> @@ -0,0 +1,93 @@
> +#!/bin/bash
> +# mkfs.btrfs must failed on a thin provision device with very small
> +# backing size and big virtual size.
> +
> +source "$TEST_TOP/common"
> +
> +check_prereq mkfs.btrfs
> +
> +setup_root_helper
> +prepare_test_dev
> +
> +# Backing data dev
> +DMTHIN_DATA_NAME="thin-data"
> +DMTHIN_DATA_DEV="/dev/mapper/$DMTHIN_DATA_NAME"
> +# Backing metadata dev
> +DMTHIN_META_NAME="thin-meta"
> +DMTHIN_META_DEV="/dev/mapper/$DMTHIN_META_NAME"
> +# Backing pool dev (combination of above)
> +DMTHIN_POOL_NAME="thin-pool"
> +DMTHIN_POOL_DEV="/dev/mapper/$DMTHIN_POOL_NAME"
> +# Thin volume
> +DMTHIN_VOL_NAME="thin-vol"
> +DMTHIN_VOL_DEV="/dev/mapper/$DMTHIN_VOL_NAME"
> +
> +dmthin_cleanup()
> +{
> +	# wait for device to be fully settled
> +	run_check $SUDO_HELPER udevadm settle
> +	run_check $SUDO_HELPER dmsetup remove $DMTHIN_VOL_NAME
> +	run_check $SUDO_HELPER dmsetup remove $DMTHIN_POOL_NAME
> +	run_check $SUDO_HELPER dmsetup remove $DMTHIN_META_NAME
> +	run_check $SUDO_HELPER dmsetup remove $DMTHIN_DATA_NAME
> +}
> +
> +sector_size=512		  # in bytes
> +data_dev_size=$((1 * 1024 * 1024 / $sector_size))   # 1M
> +virtual_size=$((1 * 1024 * 1024 * 1024 * 1024 / $sector_size))  # 1T
> +cluster_size=1024	  # 512k in sectors
> +low_water=$((104857600 / $cluster_size/ $sector_size))  # 100M / $cluster_size, in sectors
> +
> +# Need to make linear metadata and data devs.  From kernel docs:
> +# As a guide, we suggest you calculate the number of bytes to use in the
> +# metadata device as 48 * $data_dev_size / $data_block_size but round it up
> +# to 2MB (4096 sectors) if the answer is smaller.
> +# So do that:
> +meta_dev_size=$((48 * $data_dev_size / $cluster_size))
> +if [ "$meta_dev_size" -lt "4096" ]; then
> +        meta_dev_size=4096      # 2MB
> +fi
> +
> +meta_dev_offset=0
> +total_data_dev_size=$(($meta_dev_offset + $meta_dev_size + $data_dev_size))
> +
> +run_check truncate -s0 img
> +chmod a+w img
> +run_check truncate -s"$(($total_data_dev_size * $sector_size))" img
> +
> +dm_backing_dev=`run_check_stdout $SUDO_HELPER losetup --find --show img`
> +
> +# Metadata device
> +DMTHIN_META_TABLE="0 $meta_dev_size linear $dm_backing_dev $meta_dev_offset"
> +run_check $SUDO_HELPER dmsetup create $DMTHIN_META_NAME --table "$DMTHIN_META_TABLE"

What about using lvm other than plain dmsetup to create thin provision
devices?
IIRC this should be much easier to implement, without all the linear
target hassles.

Thanks,
Qu

> +
> +# Data device
> +data_dev_offset=$((meta_dev_offset + $meta_dev_size))
> +DMTHIN_DATA_TABLE="0 $data_dev_size linear $dm_backing_dev $data_dev_offset"
> +run_check $SUDO_HELPER dmsetup create $DMTHIN_DATA_NAME --table "$DMTHIN_DATA_TABLE"
> +
> +# Zap the pool metadata dev
> +run_check dd if=/dev/zero of=$DMTHIN_META_DEV bs=4096 count=1
> +
> +# Thin pool
> +# "start length thin-pool metadata_dev data_dev data_block_size low_water_mark"
> +DMTHIN_POOL_TABLE="0 $data_dev_size thin-pool $DMTHIN_META_DEV $DMTHIN_DATA_DEV $cluster_size $low_water"
> +run_check $SUDO_HELPER dmsetup create $DMTHIN_POOL_NAME --table "$DMTHIN_POOL_TABLE"
> +
> +# Thin volume
> +pool_id=$RANDOM
> +run_check $SUDO_HELPER dmsetup message $DMTHIN_POOL_DEV 0 "create_thin $pool_id"
> +
> +# start length thin pool_dev dev_id [external_origin_dev]
> +DMTHIN_VOL_TABLE="0 $virtual_size thin $DMTHIN_POOL_DEV $pool_id"
> +run_check $SUDO_HELPER dmsetup create $DMTHIN_VOL_NAME --table "$DMTHIN_VOL_TABLE"
> +
> +# mkfs.btrfs should fail due to the small backing device
> +run_mustfail "should fail for samll backing size thin provision device" \
> +	     $SUDO_HELPER "$TOP/mkfs.btrfs" -f "$@" "$DMTHIN_VOL_DEV"
> +
> +#cleanup
> +dmthin_cleanup
> +run_mayfail $SUDO_HELPER losetup -d $dm_backing_dev
> +run_check truncate -s0 img
> +rm img
>