diff --git a/tests/zfs-tests/tests/functional/fallocate/fallocate_punch-hole.ksh b/tests/zfs-tests/tests/functional/fallocate/fallocate_punch-hole.ksh
index ca037fdff..d01017f9e 100755
--- a/tests/zfs-tests/tests/functional/fallocate/fallocate_punch-hole.ksh
+++ b/tests/zfs-tests/tests/functional/fallocate/fallocate_punch-hole.ksh
@@ -23,6 +23,7 @@
 #
 # Copyright (c) 2020 by Lawrence Livermore National Security, LLC.
 # Copyright (c) 2021 by The FreeBSD Foundation.
+# Copyright (c) 2022 by Delphix. All rights reserved.
 #
 
 . $STF_SUITE/include/libtest.shlib
@@ -35,6 +36,10 @@
 # 1. Create a dense file
 # 2. Punch an assortment of holes in the file and verify the result.
 #
+# Note: We can't compare exact block numbers as reported by du, because
+# different backing stores may allocate different numbers of blocks for
+# the same amount of data.
+#
 
 verify_runnable "global"
 
@@ -60,27 +65,24 @@ function cleanup
 	[[ -e $TESTDIR ]] && log_must rm -f $FILE
 }
 
-function check_reported_size
+function get_reported_size
 {
-	typeset expected_size=$1
-
-	if ! [ -e "${FILE}" ]; then
+	if ! [ -e "$FILE" ]; then
 		log_fail "$FILE does not exist"
 	fi
-		
-	reported_size=$(du "${FILE}" | awk '{print $1}')
-	if [ "$reported_size" != "$expected_size" ]; then
-		log_fail "Incorrect reported size: $reported_size != $expected_size"
-	fi
+
+	sync_pool $TESTPOOL >/dev/null 2>&1
+	du "$FILE" | awk '{print $1}'
 }
 
 function check_apparent_size
 {
 	typeset expected_size=$1
 
-	apparent_size=$(stat_size "${FILE}")
+	apparent_size=$(stat_size "$FILE")
 	if [ "$apparent_size" != "$expected_size" ]; then
-		log_fail "Incorrect apparent size: $apparent_size != $expected_size"
+		log_fail \
+		    "Incorrect apparent size: $apparent_size != $expected_size"
 	fi
 }
 
@@ -90,30 +92,36 @@ log_onexit cleanup
 
 # Create a dense file and check it is the correct size.
 log_must file_write -o create -f $FILE -b $BLKSZ -c 8
-sync_pool $TESTPOOL
-log_must check_reported_size 1027
+full_size=$(get_reported_size)
 
-# Punch a hole for the first full block.
+# Punch a hole for the first full block. The reported size should decrease.
 log_must punch_hole 0 $BLKSZ $FILE
-sync_pool $TESTPOOL
-log_must check_reported_size 899
+one_hole=$(get_reported_size)
+[[ $full_size -gt $one_hole ]] || log_fail \
+    "One hole failure: $full_size -> $one_hole"
 
-# Partially punch a hole in the second block.
+# Partially punch a hole in the second block. The reported size should
+# remain constant.
 log_must punch_hole $BLKSZ $((BLKSZ / 2)) $FILE
-sync_pool $TESTPOOL
-log_must check_reported_size 899
+partial_hole=$(get_reported_size)
+[[ $one_hole -eq $partial_hole ]] || log_fail \
+    "Partial hole failure: $one_hole -> $partial_hole"
 
-# Punch a hole which overlaps the third and fourth block.
+# Punch a hole which overlaps the third and fourth block. The reported size
+# should remain constant.
 log_must punch_hole $(((BLKSZ * 2) + (BLKSZ / 2))) $((BLKSZ)) $FILE
-sync_pool $TESTPOOL
-log_must check_reported_size 899
+overlap_hole=$(get_reported_size)
+[[ $one_hole -eq $overlap_hole ]] || log_fail \
+    "Overlap hole failure: $one_hole -> $overlap_hole"
 
-# Punch a hole from the fifth block past the end of file.  The apparent
-# file size should not change since --keep-size is implied.
+# Punch a hole from the fifth block past the end of file.  The reported size
+# should decrease, and the apparent file size should not change since
+# --keep-size is implied.
 apparent_size=$(stat_size $FILE)
 log_must punch_hole $((BLKSZ * 4)) $((BLKSZ * 10)) $FILE
-sync_pool $TESTPOOL
-log_must check_reported_size 387
+eof_hole=$(get_reported_size)
+[[ $overlap_hole -gt $eof_hole ]] || log_fail \
+    "EOF hole failure: $overlap_hole -> $eof_hole"
 log_must check_apparent_size $apparent_size
 
 log_pass "Ensure holes can be punched in files making them sparse"
diff --git a/tests/zfs-tests/tests/functional/fallocate/fallocate_zero-range.ksh b/tests/zfs-tests/tests/functional/fallocate/fallocate_zero-range.ksh
index d8f14273c..47dd06cc0 100755
--- a/tests/zfs-tests/tests/functional/fallocate/fallocate_zero-range.ksh
+++ b/tests/zfs-tests/tests/functional/fallocate/fallocate_zero-range.ksh
@@ -23,6 +23,7 @@
 #
 # Copyright (c) 2020 by Lawrence Livermore National Security, LLC.
 # Copyright (c) 2021 by The FreeBSD Foundation.
+# Copyright (c) 2022 by Delphix. All rights reserved.
 #
 
 . $STF_SUITE/include/libtest.shlib
@@ -35,6 +36,10 @@
 # 1. Create a dense file
 # 2. Zero various ranges in the file and verify the result.
 #
+# Note: We can't compare exact block numbers as reported by du, because
+# different backing stores may allocate different numbers of blocks for
+# the same amount of data.
+#
 
 verify_runnable "global"
 
@@ -50,28 +55,24 @@ function cleanup
 	[[ -e $TESTDIR ]] && log_must rm -f $FILE
 }
 
-# Helpfully, this function expects kilobytes, and check_apparent_size expects bytes.
-function check_reported_size
+function get_reported_size
 {
-	typeset expected_size=$1
-
-	if ! [ -e "${FILE}" ]; then
+	if ! [ -e "$FILE" ]; then
 		log_fail "$FILE does not exist"
 	fi
-		
-	reported_size=$(du "${FILE}" | awk '{print $1}')
-	if [ "$reported_size" != "$expected_size" ]; then
-		log_fail "Incorrect reported size: $reported_size != $expected_size"
-	fi
+
+	sync_pool $TESTPOOL >/dev/null 2>&1
+	du "$FILE" | awk '{print $1}'
 }
 
 function check_apparent_size
 {
 	typeset expected_size=$1
 
-	apparent_size=$(stat_size "${FILE}")
+	apparent_size=$(stat_size "$FILE")
 	if [ "$apparent_size" != "$expected_size" ]; then
-		log_fail "Incorrect apparent size: $apparent_size != $expected_size"
+		log_fail \
+		    "Incorrect apparent size: $apparent_size != $expected_size"
 	fi
 }
 
@@ -82,38 +83,46 @@ log_onexit cleanup
 # Create a dense file and check it is the correct size.
 log_must file_write -o create -f $FILE -b $BLKSZ -c 8
 sync_pool $TESTPOOL
-log_must check_reported_size 1027
+full_size=$(get_reported_size)
 
-# Zero a range covering the first full block.
+# Zero a range covering the first full block. The reported size should decrease.
 log_must zero_range 0 $BLKSZ $FILE
-sync_pool $TESTPOOL
-log_must check_reported_size 899
+one_range=$(get_reported_size)
+[[ $full_size -gt $one_range ]] || log_fail \
+    "One range failure: $full_size -> $one_range"
 
-# Partially zero a range in the second block.
+# Partially zero a range in the second block. The reported size should
+# remain constant.
 log_must zero_range $BLKSZ $((BLKSZ / 2)) $FILE
-sync_pool $TESTPOOL
-log_must check_reported_size 899
+partial_range=$(get_reported_size)
+[[ $one_range -eq $partial_range ]] || log_fail \
+    "Partial range failure: $one_range -> $partial_range"
 
-# Zero range which overlaps the third and fourth block.
+# Zero range which overlaps the third and fourth block. The reported size
+# should remain constant.
 log_must zero_range $(((BLKSZ * 2) + (BLKSZ / 2))) $((BLKSZ)) $FILE
-sync_pool $TESTPOOL
-log_must check_reported_size 899
+overlap_range=$(get_reported_size)
+[[ $one_range -eq $overlap_range ]] || log_fail \
+    "Overlap range failure: $one_range -> $overlap_range"
 
 # Zero range from the fifth block past the end of file, with --keep-size.
-# The apparent file size must not change, since we did specify --keep-size.
+# The reported size should decrease, and the apparent file size must not
+# change, since we did specify --keep-size.
 apparent_size=$(stat_size $FILE)
 log_must fallocate --keep-size --zero-range --offset $((BLKSZ * 4)) --length $((BLKSZ * 10)) "$FILE"
-sync_pool $TESTPOOL
-log_must check_reported_size 387
+eof_range=$(get_reported_size)
+[[ $overlap_range -gt $eof_range ]] || log_fail \
+    "EOF range failure: $overlap_range -> $eof_range"
 log_must check_apparent_size $apparent_size
 
 # Zero range from the fifth block past the end of file.  The apparent
 # file size should change since --keep-size is not implied, unlike
-# with PUNCH_HOLE.
+# with PUNCH_HOLE. The reported size should remain constant.
 apparent_size=$(stat_size $FILE)
 log_must zero_range $((BLKSZ * 4)) $((BLKSZ * 10)) $FILE
-sync_pool $TESTPOOL
-log_must check_reported_size 387
+eof_range2=$(get_reported_size)
+[[ $eof_range -eq $eof_range2 ]] || log_fail \
+    "Second EOF range failure: $eof_range -> $eof_range2"
 log_must check_apparent_size $((BLKSZ * 14))
 
 log_pass "Ensure ranges can be zeroed in files"