9 files changed, 45 insertions, 6 deletions
diff --git a/tests/qemu-iotests/106 b/tests/qemu-iotests/106
index ae0fc46691..55548439aa 100755
--- a/tests/qemu-iotests/106
+++ b/tests/qemu-iotests/106
@@ -40,6 +40,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 _supported_fmt raw
 _supported_proto file fuse
 _supported_os Linux
+_require_disk_usage
 
 # in kB
 CREATION_SIZE=128
diff --git a/tests/qemu-iotests/125 b/tests/qemu-iotests/125
index 46279d6b38..708e7c5ba2 100755
--- a/tests/qemu-iotests/125
+++ b/tests/qemu-iotests/125
@@ -35,7 +35,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 
 get_image_size_on_host()
 {
-    echo $(($(stat -c '%b * %B' "$TEST_IMG_FILE")))
+    disk_usage "$TEST_IMG_FILE"
 }
 
 # get standard environment and filters
diff --git a/tests/qemu-iotests/175 b/tests/qemu-iotests/175
index f74f053b71..bbbf550a5a 100755
--- a/tests/qemu-iotests/175
+++ b/tests/qemu-iotests/175
@@ -77,6 +77,7 @@ _supported_os Linux
 
 _default_cache_mode none
 _supported_cache_modes none directsync
+_require_disk_usage
 
 size=$((1 * 1024 * 1024))
 
diff --git a/tests/qemu-iotests/221 b/tests/qemu-iotests/221
index c463fd4b11..eba00b80ad 100755
--- a/tests/qemu-iotests/221
+++ b/tests/qemu-iotests/221
@@ -41,6 +41,7 @@ _supported_os Linux
 
 _default_cache_mode writeback
 _supported_cache_modes writeback writethrough unsafe
+_require_disk_usage
 
 echo
 echo "=== Check mapping of unaligned raw image ==="
diff --git a/tests/qemu-iotests/253 b/tests/qemu-iotests/253
index 35039d20a8..6da85e6a11 100755
--- a/tests/qemu-iotests/253
+++ b/tests/qemu-iotests/253
@@ -41,6 +41,7 @@ _supported_os Linux
 
 _default_cache_mode none
 _supported_cache_modes none directsync
+_require_disk_usage
 
 echo
 echo "=== Check mapping of unaligned raw image ==="
diff --git a/tests/qemu-iotests/308 b/tests/qemu-iotests/308
index ea81dc496a..6eced3aefb 100755
--- a/tests/qemu-iotests/308
+++ b/tests/qemu-iotests/308
@@ -51,6 +51,7 @@ _unsupported_fmt vpc
 
 _supported_proto file # We create the FUSE export manually
 _supported_os Linux # We need /dev/urandom
+_require_disk_usage
 
 # $1: Export ID
 # $2: Options (beyond the node-name and ID)
@@ -290,7 +291,7 @@ echo '--- Try growing non-growable export ---'
 
 # Get the current size so we can write beyond the EOF
 orig_len=$(get_proto_len "$EXT_MP" "$TEST_IMG")
-orig_disk_usage=$(stat -c '%b' "$TEST_IMG")
+orig_disk_usage=$(disk_usage "$TEST_IMG")
 
 # Should fail (exports are non-growable by default)
 # (Note that qemu-io can never write beyond the EOF, so we have to use
@@ -312,7 +313,7 @@ else
     echo 'OK: Post-truncate image size is as expected'
 fi
 
-new_disk_usage=$(stat -c '%b' "$TEST_IMG")
+new_disk_usage=$(disk_usage "$TEST_IMG")
 if [ "$new_disk_usage" -gt "$orig_disk_usage" ]; then
     echo 'OK: Disk usage grew with fallocate'
 else
diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 237f746af8..e977cb4eb6 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -996,6 +996,36 @@ _require_large_file()
     rm "$FILENAME"
 }
 
+# Check whether disk_usage can be reliably used.
+_require_disk_usage()
+{
+    local unusable=false
+    # ZFS triggers known failures on this front; it does not immediately
+    # allocate files, and then aggressively compresses writes even when full
+    # allocation was requested.
+    if [ -z "$TEST_IMG_FILE" ]; then
+        FILENAME="$TEST_IMG"
+    else
+        FILENAME="$TEST_IMG_FILE"
+    fi
+    if [ -e "FILENAME" ]; then
+        echo "unwilling to overwrite existing file"
+        exit 1
+    fi
+    $QEMU_IMG create -f raw "$FILENAME" 5M > /dev/null
+    if [ $(disk_usage "$FILENAME") -gt $((1024*1024)) ]; then
+        unusable=true
+    fi
+    $QEMU_IMG create -f raw -o preallocation=full "$FILENAME" 5M > /dev/null
+    if [ $(disk_usage "$FILENAME") -lt $((4*1024*1024)) ]; then
+        unusable=true
+    fi
+    rm -f "$FILENAME"
+    if $unusable; then
+        _notrun "file system on $TEST_DIR does not handle sparse files nicely"
+    fi
+}
+
 # Check that a set of devices is available in the QEMU binary
 #
 _require_devices()
diff --git a/tests/qemu-iotests/tests/mirror-sparse b/tests/qemu-iotests/tests/mirror-sparse
index 8c52a4e244..cfcaa600ab 100755
--- a/tests/qemu-iotests/tests/mirror-sparse
+++ b/tests/qemu-iotests/tests/mirror-sparse
@@ -40,6 +40,7 @@ cd ..
 _supported_fmt qcow2 raw  # Format of the source. dst is always raw file
 _supported_proto file
 _supported_os Linux
+_require_disk_usage
 
 echo
 echo "=== Initial image setup ==="
@@ -96,13 +97,15 @@ _send_qemu_cmd $h1 '{"execute": "blockdev-del", "arguments":
                 {"node-name": "dst"}}' 'return' \
                   | _filter_block_job_offset | _filter_block_job_len
 $QEMU_IMG compare -U -f $IMGFMT -F raw $TEST_IMG.base $TEST_IMG
+# Some filesystems can fudge allocations for various reasons; rather
+# than expecting precise 2M and 20M images, it is better to allow for slop.
 result=$(disk_usage $TEST_IMG)
-if test $result -lt $((3*1024*1024)); then
+if test $result -lt $((4*1024*1024)); then
     actual=sparse
-elif test $result = $((20*1024*1024)); then
+elif test $result -gt $((19*1024*1024)); then
     actual=full
 else
-    actual=unknown
+    actual="unexpected size ($result)"
 fi
 echo "Destination is $actual; expected $expected"
 }
diff --git a/tests/qemu-iotests/tests/write-zeroes-unmap b/tests/qemu-iotests/tests/write-zeroes-unmap
index 7cfeeaf839..f90fb8e8d2 100755
--- a/tests/qemu-iotests/tests/write-zeroes-unmap
+++ b/tests/qemu-iotests/tests/write-zeroes-unmap
@@ -32,6 +32,7 @@ cd ..
 _supported_fmt raw
 _supported_proto file
 _supported_os Linux
+_require_disk_usage
 
 create_test_image() {
     _make_test_img -f $IMGFMT 1m