This function preallocates metadata structures and then extends the
image to its new size, but that new size calculation is wrong because
it doesn't take into account that the host_offset variable is always
cluster-aligned.
This problem can be reproduced with preallocation=metadata when the
original size is not cluster-aligned but the new size is. In this case
the final image size will be shorter than expected.
qemu-img create -f qcow2 img.qcow2 31k
qemu-img resize --preallocation=metadata img.qcow2 128k
Signed-off-by: Alberto Garcia
---
block/qcow2.c | 1 +
tests/qemu-iotests/125 | 40 +-
tests/qemu-iotests/125.out | 28 --
3 files changed, 49 insertions(+), 20 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 77c43ce178..1cb5daf39a 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3135,6 +3135,7 @@ static int coroutine_fn preallocate_co(BlockDriverState
*bs, uint64_t offset,
error_setg_errno(errp, -ret, "Allocating clusters failed");
goto out;
}
+host_offset += offset_into_cluster(s, offset);
for (m = meta; m != NULL; m = m->next) {
m->prealloc = true;
diff --git a/tests/qemu-iotests/125 b/tests/qemu-iotests/125
index 7cb1c19730..1f35598b2b 100755
--- a/tests/qemu-iotests/125
+++ b/tests/qemu-iotests/125
@@ -168,24 +168,28 @@ done
$QEMU_IMG create -f raw "$TEST_IMG.base" 128k | _filter_img_create
$QEMU_IO -c 'write -q -P 1 0 128k' -f raw "$TEST_IMG.base"
for orig_size in 31k 33k; do
-echo "--- Resizing image from $orig_size to 96k ---"
-_make_test_img -F raw -b "$TEST_IMG.base" -o cluster_size=64k "$orig_size"
-$QEMU_IMG resize -f "$IMGFMT" --preallocation=full "$TEST_IMG" 96k
-# The first part of the image should contain data from the backing file
-$QEMU_IO -c "read -q -P 1 0 ${orig_size}" "$TEST_IMG"
-# The resized part of the image should contain zeroes
-$QEMU_IO -c "read -q -P 0 ${orig_size} 63k" "$TEST_IMG"
-# If the image does not have an external data file we can also verify its
-# actual size. The resized image should have 7 clusters:
-# header, L1 table, L2 table, refcount table, refcount block, 2 data
clusters
-if ! _get_data_file "$TEST_IMG" > /dev/null; then
-expected_file_length=$((65536 * 7))
-file_length=$(stat -c '%s' "$TEST_IMG_FILE")
-if [ "$file_length" != "$expected_file_length" ]; then
-echo "ERROR: file length $file_length (expected
$expected_file_length)"
-fi
-fi
-echo
+for dst_size in 96k 128k; do
+for prealloc in metadata full; do
+echo "--- Resizing image from $orig_size to $dst_size
(preallocation=$prealloc) ---"
+_make_test_img -F raw -b "$TEST_IMG.base" -o cluster_size=64k
"$orig_size"
+$QEMU_IMG resize -f "$IMGFMT" --preallocation="$prealloc"
"$TEST_IMG" "$dst_size"
+# The first part of the image should contain data from the backing
file
+$QEMU_IO -c "read -q -P 1 0 ${orig_size}" "$TEST_IMG"
+# The resized part of the image should contain zeroes
+$QEMU_IO -c "read -q -P 0 ${orig_size} 63k" "$TEST_IMG"
+# If the image does not have an external data file we can also
verify its
+# actual size. The resized image should have 7 clusters:
+# header, L1 table, L2 table, refcount table, refcount block, 2
data clusters
+if ! _get_data_file "$TEST_IMG" > /dev/null; then
+expected_file_length=$((65536 * 7))
+file_length=$(stat -c '%s' "$TEST_IMG_FILE")
+if [ "$file_length" != "$expected_file_length" ]; then
+echo "ERROR: file length $file_length (expected
$expected_file_length)"
+fi
+fi
+echo
+done
+done
done
# success, all done
diff --git a/tests/qemu-iotests/125.out b/tests/qemu-iotests/125.out
index 7f76f7af20..63a6e9e8a9 100644
--- a/tests/qemu-iotests/125.out
+++ b/tests/qemu-iotests/125.out
@@ -768,11 +768,35 @@ wrote 81920/81920 bytes at offset 2048000
80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
Formatting 'TEST_DIR/t.IMGFMT.base', fmt=raw size=131072
Resizing image from 31k to 96k ---
+--- Resizing image from 31k to 96k (preallocation=metadata) ---
Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=31744
backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=raw
Image resized.
Resizing image from 33k to 96k ---
+--- Resizing image from 31k to 96k (preallocation=full) ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=31744
backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=raw
+Image resized.
+
+--- Resizing image from 31k to 128k (preallocation=metadata) ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=31744
backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=raw
+Image resized.
+
+--- Resizing image from 31k to 128k