diff options
| author | Denis Plotnikov <dplotnikov@virtuozzo.com> | 2020-05-07 11:25:18 +0300 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2020-05-13 14:20:31 +0200 |
| commit | 572ad9783f3e728a70617ce6bf144c09de3add50 (patch) | |
| tree | 74fc24fcf09d7ed4acdf55949fa52b2d45726469 /block/qcow2.h | |
| parent | d5c75ec500d96f1d93447f990cd5a4ef5ba27fae (diff) | |
qcow2: introduce compression type feature
The patch adds some preparation parts for incompatible compression type
feature to qcow2 allowing the use different compression methods for
image clusters (de)compressing.
It is implied that the compression type is set on the image creation and
can be changed only later by image conversion, thus compression type
defines the only compression algorithm used for the image, and thus,
for all image clusters.
The goal of the feature is to add support of other compression methods
to qcow2. For example, ZSTD which is more effective on compression than ZLIB.
The default compression is ZLIB. Images created with ZLIB compression type
are backward compatible with older qemu versions.
Adding of the compression type breaks a number of tests because now the
compression type is reported on image creation and there are some changes
in the qcow2 header in size and offsets.
The tests are fixed in the following ways:
* filter out compression_type for many tests
* fix header size, feature table size and backing file offset
affected tests: 031, 036, 061, 080
header_size +=8: 1 byte compression type
7 bytes padding
feature_table += 48: incompatible feature compression type
backing_file_offset += 56 (8 + 48 -> header_change + feature_table_change)
* add "compression type" for test output matching when it isn't filtered
affected tests: 049, 060, 061, 065, 082, 085, 144, 182, 185, 198, 206,
242, 255, 274, 280
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
QAPI part:
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200507082521.29210-2-dplotnikov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block/qcow2.h')
| -rw-r--r-- | block/qcow2.h | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/block/qcow2.h b/block/qcow2.h index f4de0a27d5..6a8b82e6cc 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -146,8 +146,16 @@ typedef struct QCowHeader { uint32_t refcount_order; uint32_t header_length; + + /* Additional fields */ + uint8_t compression_type; + + /* header must be a multiple of 8 */ + uint8_t padding[7]; } QEMU_PACKED QCowHeader; +QEMU_BUILD_BUG_ON(!QEMU_IS_ALIGNED(sizeof(QCowHeader), 8)); + typedef struct QEMU_PACKED QCowSnapshotHeader { /* header is 8 byte aligned */ uint64_t l1_table_offset; @@ -216,13 +224,16 @@ enum { QCOW2_INCOMPAT_DIRTY_BITNR = 0, QCOW2_INCOMPAT_CORRUPT_BITNR = 1, QCOW2_INCOMPAT_DATA_FILE_BITNR = 2, + QCOW2_INCOMPAT_COMPRESSION_BITNR = 3, QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR, QCOW2_INCOMPAT_CORRUPT = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR, QCOW2_INCOMPAT_DATA_FILE = 1 << QCOW2_INCOMPAT_DATA_FILE_BITNR, + QCOW2_INCOMPAT_COMPRESSION = 1 << QCOW2_INCOMPAT_COMPRESSION_BITNR, QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY | QCOW2_INCOMPAT_CORRUPT - | QCOW2_INCOMPAT_DATA_FILE, + | QCOW2_INCOMPAT_DATA_FILE + | QCOW2_INCOMPAT_COMPRESSION, }; /* Compatible feature bits */ @@ -366,6 +377,13 @@ typedef struct BDRVQcow2State { bool metadata_preallocation_checked; bool metadata_preallocation; + /* + * Compression type used for the image. Default: 0 - ZLIB + * The image compression type is set on image creation. + * For now, the only way to change the compression type + * is to convert the image with the desired compression type set. + */ + Qcow2CompressionType compression_type; } BDRVQcow2State; typedef struct Qcow2COWRegion { |