Add a test case for the ZSTD header

Ensure the actual psize and level are saved and restored correctly

Signed-off-by: Allan Jude <allan@klarasystems.com>

tests/zfs-tests/tests/functional/cli_root/zdb/zdb_decompress_zstd.ksh

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+#!/bin/ksh
+
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+#
+# Copyright (c) 2016-2018, Allan Jude [1]
+#
+# [1] Portions of this software were developed by Allan Jude
+#     under sponsorship from the FreeBSD Foundation.
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# Description:
+# zdb -Z pool <objid> will display the ZSTD compression header
+#     This will contain the actual length of the compressed data, as well as
+#     the version of ZSTD used to compress the block, and the compression level
+#
+# Strategy:
+# 1. Create a pool, set compression to zstd-<random level>
+# 2. Write some identifiable data to a file
+# 3. Run zdb -Zddddddbbbbbb against the file
+# 4. Record the DVA, lsize, and psize, and ZSTD header of L0 block 0
+# 5. Check that the ZSTD length is less than psize
+# 6. Check that the ZSTD level matches the level we requested
+# 7. Run zdb -R with :dr flags and confirm the size and content match
+#
+
+function cleanup
+{
+	datasetexists $TESTPOOL && destroy_pool $TESTPOOL
+}
+
+log_assert "Verify zdb -Z (read ZSTD header) works as expected"
+log_onexit cleanup
+src_data=$STF_SUITE/tests/functional/cli_root/zdb/zstd_test_data.txt
+init_data=$TESTDIR/file1
+write_count=128
+blksize=131072
+verify_runnable "global"
+verify_disk_count "$DISKS" 2
+random_level=$((RANDOM%19 + 1))
+
+default_mirror_setup_noexit $DISKS
+log_must zfs set recordsize=$blksize $TESTPOOL/$TESTFS
+log_must zfs set compression=zstd-$random_level $TESTPOOL/$TESTFS
+
+# write the 1k of text 128 times
+for i in {1..$write_count}
+do
+	cat $src_data >> $init_data
+done
+
+sync_pool $TESTPOOL true
+
+# get object number of file
+listing=$(ls -i $init_data)
+set -A array $listing
+obj=${array[0]}
+log_note "file $init_data has object number $obj"
+
+output=$(zdb -Zddddddbbbbbb $TESTPOOL/$TESTFS $obj 2> /dev/null \
+    |grep -m 1 "L0 DVA" |head -n1)
+dva=$(sed -Ene 's/^.+DVA\[0\]=<([^>]+)>.*$/\1/p' <<< "$output")
+log_note "block 0 of $init_data has a DVA of $dva"
+
+# use the length reported by zdb -ddddddbbbbbb
+size_str=$(sed -Ene 's/^.+ size=([^ ]+) .*$/\1/p' <<< "$output")
+# convert sizes to decimal
+lsize=$(echo $size_str |awk '{split($0,array,"/")} END{print array[1]}')
+lsize_orig=$lsize
+lsize=${lsize%?}
+lsize_bytes=$((16#$lsize))
+psize=$(echo $size_str |awk '{split($0,array,"/")} END{print array[2]}')
+psize_orig=$psize
+psize=${psize%?}
+psize_bytes=$((16#$psize))
+log_note "block size $size_str"
+
+# Get the ZSTD header reported by zdb -Z
+zstd_str=$(sed -Ene 's/^.+ ZSTD:size=([^:]+):version=([^:]+):level=([^:]+):.*$/\1:\2:\3/p' <<< "$output")
+zstd_size=$(echo "$zstd_str" |awk '{split($0,array,":")} END{print array[1]}')
+log_note "ZSTD compressed size $zstd_size"
+(( $psize_bytes < $zstd_size )) && log_fail \
+"zdb -Z failed: physical block size was less than header content length ($psize_bytes < $zstd_size)"
+
+zstd_version=$(echo "$zstd_str" |awk '{split($0,array,":")} END{print array[2]}')
+log_note "ZSTD version $zstd_version"
+
+zstd_level=$(echo "$zstd_str" |awk '{split($0,array,":")} END{print array[3]}')
+log_note "ZSTD level $zstd_level"
+(( $zstd_level != $random_level )) && log_fail \
+"zdb -Z failed: compression level did not match header level ($zstd_level < $random_level)"
+
+vdev=$(echo "$dva" |awk '{split($0,array,":")} END{print array[1]}')
+offset=$(echo "$dva" |awk '{split($0,array,":")} END{print array[2]}')
+# Check the first 1024 bytes
+output=$(ZDB_NO_ZLE="true" zdb -R $TESTPOOL $vdev:$offset:$size_str:dr 2> /dev/null)
+outsize=$(wc -c <<< "$output")
+(( $outsize != $blksize )) && log_fail \
+"zdb -Z failed to decompress the data to the expected length ($outsize != $lsize_bytes)"
+cmp $init_data - <<< "$output"
+(( $? != 0 )) && log_fail "zdb -R :dr failed to decompress the data properly"
+
+log_pass "zdb -Z flag (ZSTD compression header) works as expected"

tests/zfs-tests/tests/functional/cli_root/zdb/zstd_test_data.txt

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+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim..