diff options
| -rw-r--r-- | block/qcow2.c | 34 | ||||
| -rw-r--r-- | tests/qemu-iotests/244.out | 9 |
2 files changed, 38 insertions, 5 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 2fb43c6f7e..9727ae8fe3 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -3503,6 +3503,28 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) ret = -EINVAL; goto out; } + if (qcow2_opts->data_file_raw && + qcow2_opts->preallocation == PREALLOC_MODE_OFF) + { + /* + * data-file-raw means that "the external data file can be + * read as a consistent standalone raw image without looking + * at the qcow2 metadata." It does not say that the metadata + * must be ignored, though (and the qcow2 driver in fact does + * not ignore it), so the L1/L2 tables must be present and + * give a 1:1 mapping, so you get the same result regardless + * of whether you look at the metadata or whether you ignore + * it. + */ + qcow2_opts->preallocation = PREALLOC_MODE_METADATA; + + /* + * Cannot use preallocation with backing files, but giving a + * backing file when specifying data_file_raw is an error + * anyway. + */ + assert(!qcow2_opts->has_backing_file); + } if (qcow2_opts->data_file) { if (version < 3) { @@ -4238,6 +4260,18 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, error_setg_errno(errp, -ret, "Failed to grow the L1 table"); goto fail; } + + if (data_file_is_raw(bs) && prealloc == PREALLOC_MODE_OFF) { + /* + * When creating a qcow2 image with data-file-raw, we enforce + * at least prealloc=metadata, so that the L1/L2 tables are + * fully allocated and reading from the data file will return + * the same data as reading from the qcow2 image. When the + * image is grown, we must consequently preallocate the + * metadata structures to cover the added area. + */ + prealloc = PREALLOC_MODE_METADATA; + } } switch (prealloc) { diff --git a/tests/qemu-iotests/244.out b/tests/qemu-iotests/244.out index 7269b4295a..1a3ae31dde 100644 --- a/tests/qemu-iotests/244.out +++ b/tests/qemu-iotests/244.out @@ -83,7 +83,7 @@ qcow2 file size after I/O: 327680 === Standalone image with external data file (valid raw) === Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data data_file_raw=on -qcow2 file size before I/O: 196616 +qcow2 file size before I/O: 327680 wrote 4194304/4194304 bytes at offset 1048576 4 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) @@ -93,11 +93,10 @@ wrote 3145728/3145728 bytes at offset 3145728 3 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) No errors were found on the image. -[{ "start": 0, "length": 1048576, "depth": 0, "zero": true, "data": false}, -{ "start": 1048576, "length": 1048576, "depth": 0, "zero": false, "data": true, "offset": 1048576}, +[{ "start": 0, "length": 2097152, "depth": 0, "zero": false, "data": true, "offset": 0}, { "start": 2097152, "length": 2097152, "depth": 0, "zero": true, "data": false}, -{ "start": 4194304, "length": 1048576, "depth": 0, "zero": true, "data": false, "offset": 4194304}, -{ "start": 5242880, "length": 61865984, "depth": 0, "zero": true, "data": false}] +{ "start": 4194304, "length": 2097152, "depth": 0, "zero": true, "data": false, "offset": 4194304}, +{ "start": 6291456, "length": 60817408, "depth": 0, "zero": false, "data": true, "offset": 6291456}] read 1048576/1048576 bytes at offset 0 1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) |