* [Qemu-devel] [PATCH v3 0/3] qcow2: add zstd cluster compression
@ 2019-08-19 15:00 Denis Plotnikov
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 1/3] qcow2: introduce compression type feature Denis Plotnikov
` (3 more replies)
0 siblings, 4 replies; 9+ messages in thread
From: Denis Plotnikov @ 2019-08-19 15:00 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, den, qemu-block, armbru, mreitz
v3:
* relax the compression type setting requirement when
the compression type is not zlib [Eric, Kevin]
* add compression type values to the spec [Eric]
* fix wording in the spec and descriptions [Eric]
* fix functions descriptions [Max]
* fix zstd (de)compression functions flaws [Max]
* fix zstd related parts of configure file [Max]
* rebased to v4.1.0-rc5 and chenged the series version aiming to 4.2
v2:
* relax the compression type setting restriction in the spec
* fix qcow2 header size checking
* fix error processing and messaging
* fix qcow2 image specific info reporting
* set Qcow2CompressionType zstd config dependant
* add zstd compressed cluster format description to the spec
v1:
* extend qcow2 header instead of adding a new incompatible extension header
specification re-written accordingly
* enable zstd compression via config
* fix zstd (de)compression functions
* fix comments/description
* fix function naming
---
The goal of the patch-set is to enable qcow2 to use zstd compression for
clusters. ZSTD provides better (de)compression performance than currently
used ZLIB. Using it will improve perforamnce (reduce compression time)
when the compressed clusters is used, e.g backup scenarios.
Also, the patch-set extends qcow2 specification by adding compression_type
feature. The feature enables adding ZSTD and another compression algorithms
in the future.
Here is some measurements ZSTD vs ZLIB:
The test:
Test compresses and decompresses qemu qcow2 image with just
installed rhel-7.6 guest.
Image cluster size: 64K. Image on disk size: 2.2G
The test was conducted with brd disk to reduce the influence
of disk subsystem to the test results.
The results is given in seconds.
compress cmd:
time ./qemu-img convert -O qcow2 -c -o compression_type=[zlib|zstd]
src.img [zlib|zstd]_compressed.img
decompress cmd
time ./qemu-img convert -O qcow2
[zlib|zstd]_compressed.img uncompressed.img
The results:
compression decompression
zlib zstd zlib zstd
------------------------------------------------------------
real 65.5 16.3 (-75 %) 1.9 1.6 (-16 %)
user 65.0 15.8 5.3 2.5
sys 3.3 0.2 2.0 2.0
Both ZLIB and ZSTD gave the same compression ratio: ~1.5
compressed image size in both cases: ~1.4G
Denis Plotnikov (3):
qcow2: introduce compression type feature
qcow2: rework the cluster compression routine
qcow2: add zstd cluster compression
block/qcow2-threads.c | 172 ++++++++++++++++++++++++++++++++++----
block/qcow2.c | 100 ++++++++++++++++++++++
block/qcow2.h | 26 ++++--
configure | 34 ++++++++
docs/interop/qcow2.txt | 39 ++++++++-
include/block/block_int.h | 1 +
qapi/block-core.json | 23 ++++-
7 files changed, 371 insertions(+), 24 deletions(-)
--
2.17.0
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH v3 1/3] qcow2: introduce compression type feature
2019-08-19 15:00 [Qemu-devel] [PATCH v3 0/3] qcow2: add zstd cluster compression Denis Plotnikov
@ 2019-08-19 15:00 ` Denis Plotnikov
2019-08-27 11:49 ` Vladimir Sementsov-Ogievskiy
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 2/3] qcow2: rework the cluster compression routine Denis Plotnikov
` (2 subsequent siblings)
3 siblings, 1 reply; 9+ messages in thread
From: Denis Plotnikov @ 2019-08-19 15:00 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, den, qemu-block, armbru, mreitz
The patch adds some preparation parts for incompatible compression type
feature to QCOW2 header that indicates that *all* compressed clusters
must be (de)compressed using a certain compression type.
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.
The goal of the feature is to add support of other compression algorithms
to qcow2. For example, ZSTD which is more effective on compression than ZLIB.
It works roughly 2x faster than ZLIB providing a comparable compression ratio
and therefore provides a performance advantage in backup scenarios.
The default compression is ZLIB. Images created with ZLIB compression type
are backward compatible with older qemu versions.
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
---
block/qcow2.c | 94 +++++++++++++++++++++++++++++++++++++++
block/qcow2.h | 26 ++++++++---
docs/interop/qcow2.txt | 19 +++++++-
include/block/block_int.h | 1 +
qapi/block-core.json | 22 ++++++++-
5 files changed, 152 insertions(+), 10 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 039bdc2f7e..4e07b7e9ec 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1197,6 +1197,32 @@ static int qcow2_update_options(BlockDriverState *bs, QDict *options,
return ret;
}
+static int check_compression_type(BDRVQcow2State *s, Error **errp)
+{
+ switch (s->compression_type) {
+ case QCOW2_COMPRESSION_TYPE_ZLIB:
+ break;
+
+ default:
+ error_setg(errp, "qcow2: unknown compression type: %u",
+ s->compression_type);
+ return -ENOTSUP;
+ }
+
+ /*
+ * if the compression type differs from QCOW2_COMPRESSION_TYPE_ZLIB
+ * the incompatible feature flag must be set
+ */
+
+ if (s->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB &&
+ !(s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION_TYPE)) {
+ error_setg(errp, "qcow2: Invalid compression type setting");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
/* Called with s->lock held. */
static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
int flags, Error **errp)
@@ -1312,6 +1338,35 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
s->compatible_features = header.compatible_features;
s->autoclear_features = header.autoclear_features;
+ /*
+ * Handle compression type
+ * Older qcow2 images don't contain the compression type header.
+ * Distinguish them by the header length and use
+ * the only valid (default) compression type in that case
+ */
+ if (header.header_length > offsetof(QCowHeader, compression_type)) {
+ /* sanity check that we can read a compression type */
+ size_t min_len = offsetof(QCowHeader, compression_type) +
+ sizeof(header.compression_type);
+ if (header.header_length < min_len) {
+ error_setg(errp,
+ "Could not read compression type, "
+ "qcow2 header is too short");
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ header.compression_type = be32_to_cpu(header.compression_type);
+ s->compression_type = header.compression_type;
+ } else {
+ s->compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
+ }
+
+ ret = check_compression_type(s, errp);
+ if (ret) {
+ goto fail;
+ }
+
if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
void *feature_table = NULL;
qcow2_read_extensions(bs, header.header_length, ext_end,
@@ -2516,6 +2571,12 @@ int qcow2_update_header(BlockDriverState *bs)
total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
+ ret = check_compression_type(s, NULL);
+
+ if (ret) {
+ goto fail;
+ }
+
*header = (QCowHeader) {
/* Version 2 fields */
.magic = cpu_to_be32(QCOW_MAGIC),
@@ -2538,6 +2599,7 @@ int qcow2_update_header(BlockDriverState *bs)
.autoclear_features = cpu_to_be64(s->autoclear_features),
.refcount_order = cpu_to_be32(s->refcount_order),
.header_length = cpu_to_be32(header_length),
+ .compression_type = cpu_to_be32(s->compression_type),
};
/* For older versions, write a shorter header */
@@ -2635,6 +2697,11 @@ int qcow2_update_header(BlockDriverState *bs)
.bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
.name = "lazy refcounts",
},
+ {
+ .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
+ .bit = QCOW2_INCOMPAT_COMPRESSION_TYPE_BITNR,
+ .name = "compression type",
+ },
};
ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
@@ -3202,6 +3269,7 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
.refcount_table_offset = cpu_to_be64(cluster_size),
.refcount_table_clusters = cpu_to_be32(1),
.refcount_order = cpu_to_be32(refcount_order),
+ .compression_type = cpu_to_be32(QCOW2_COMPRESSION_TYPE_ZLIB),
.header_length = cpu_to_be32(sizeof(*header)),
};
@@ -3221,6 +3289,24 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW);
}
+ if (qcow2_opts->has_compression_type &&
+ qcow2_opts->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) {
+
+ switch (qcow2_opts->compression_type) {
+ case QCOW2_COMPRESSION_TYPE_ZLIB:
+ break;
+
+ default:
+ error_setg_errno(errp, -EINVAL, "Unknown compression type");
+ goto out;
+ }
+
+ header->compression_type = cpu_to_be32(qcow2_opts->compression_type);
+
+ header->incompatible_features |=
+ cpu_to_be64(QCOW2_INCOMPAT_COMPRESSION_TYPE);
+ }
+
ret = blk_pwrite(blk, 0, header, cluster_size, 0);
g_free(header);
if (ret < 0) {
@@ -3402,6 +3488,7 @@ static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opt
{ BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
{ BLOCK_OPT_COMPAT_LEVEL, "version" },
{ BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" },
+ { BLOCK_OPT_COMPRESSION_TYPE, "compression-type" },
{ NULL, NULL },
};
@@ -4598,6 +4685,7 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs,
.data_file = g_strdup(s->image_data_file),
.has_data_file_raw = has_data_file(bs),
.data_file_raw = data_file_is_raw(bs),
+ .compression_type = s->compression_type,
};
} else {
/* if this assertion fails, this probably means a new version was
@@ -5163,6 +5251,12 @@ static QemuOptsList qcow2_create_opts = {
.help = "Width of a reference count entry in bits",
.def_value_str = "16"
},
+ {
+ .name = BLOCK_OPT_COMPRESSION_TYPE,
+ .type = QEMU_OPT_STRING,
+ .help = "Compression method used for image clusters compression",
+ .def_value_str = "zlib"
+ },
{ /* end of list */ }
}
};
diff --git a/block/qcow2.h b/block/qcow2.h
index fc1b0d3c1e..9a241e4b9a 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -140,6 +140,7 @@ typedef struct QCowHeader {
uint32_t refcount_order;
uint32_t header_length;
+ uint32_t compression_type;
} QEMU_PACKED QCowHeader;
typedef struct QEMU_PACKED QCowSnapshotHeader {
@@ -203,16 +204,20 @@ enum {
/* Incompatible feature bits */
enum {
- QCOW2_INCOMPAT_DIRTY_BITNR = 0,
- QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
- QCOW2_INCOMPAT_DATA_FILE_BITNR = 2,
- 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_DIRTY_BITNR = 0,
+ QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
+ QCOW2_INCOMPAT_DATA_FILE_BITNR = 2,
+ QCOW2_INCOMPAT_COMPRESSION_TYPE_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_TYPE =
+ 1 << QCOW2_INCOMPAT_COMPRESSION_TYPE_BITNR,
QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY
| QCOW2_INCOMPAT_CORRUPT
- | QCOW2_INCOMPAT_DATA_FILE,
+ | QCOW2_INCOMPAT_DATA_FILE
+ | QCOW2_INCOMPAT_COMPRESSION_TYPE,
};
/* Compatible feature bits */
@@ -359,6 +364,13 @@ 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.
+ * The only way to change the compression type is to convert the image
+ * with the desired compression type set
+ */
+ uint32_t compression_type;
} BDRVQcow2State;
typedef struct Qcow2COWRegion {
diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
index af5711e533..e1be8bd5c3 100644
--- a/docs/interop/qcow2.txt
+++ b/docs/interop/qcow2.txt
@@ -109,7 +109,12 @@ in the description of a field.
An External Data File Name header extension may
be present if this bit is set.
- Bits 3-63: Reserved (set to 0)
+ Bit 3: Compression type bit. The bit must be set if
+ the compression type differs from default of zlib.
+ If the compression type is default the bit should
+ be unset.
+
+ Bits 4-63: Reserved (set to 0)
80 - 87: compatible_features
Bitmask of compatible features. An implementation can
@@ -165,6 +170,18 @@ in the description of a field.
Length of the header structure in bytes. For version 2
images, the length is always assumed to be 72 bytes.
+ 104 - 107: compression_type
+ Defines the compression method used for compressed clusters.
+ A single compression type is applied to all compressed image
+ clusters.
+ The compression type is set on image creation only.
+ The default compression type is zlib (value: 0).
+ When the compression type differs from the default
+ the compression type bit (incompatible feature bit 3)
+ must be set.
+ Available compression type values:
+ 0: zlib <https://www.zlib.net/> (default)
+
Directly after the image header, optional sections called header extensions can
be stored. Each extension has a structure like the following:
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 3aa1e832a8..4b254802e5 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -58,6 +58,7 @@
#define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
#define BLOCK_OPT_DATA_FILE "data_file"
#define BLOCK_OPT_DATA_FILE_RAW "data_file_raw"
+#define BLOCK_OPT_COMPRESSION_TYPE "compression_type"
#define BLOCK_PROBE_BUF_SIZE 512
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 0d43d4f37c..2c002ca6a9 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -78,6 +78,8 @@
#
# @bitmaps: A list of qcow2 bitmap details (since 4.0)
#
+# @compression-type: the image cluster compression method (since 4.2)
+#
# Since: 1.7
##
{ 'struct': 'ImageInfoSpecificQCow2',
@@ -89,7 +91,8 @@
'*corrupt': 'bool',
'refcount-bits': 'int',
'*encrypt': 'ImageInfoSpecificQCow2Encryption',
- '*bitmaps': ['Qcow2BitmapInfo']
+ '*bitmaps': ['Qcow2BitmapInfo'],
+ 'compression-type': 'Qcow2CompressionType'
} }
##
@@ -4274,6 +4277,18 @@
'data': [ 'v2', 'v3' ] }
+##
+# @Qcow2CompressionType:
+#
+# Compression type used in qcow2 image file
+#
+# @zlib: zlib compression, see <http://zlib.net/>
+#
+# Since: 4.2
+##
+{ 'enum': 'Qcow2CompressionType',
+ 'data': [ 'zlib' ] }
+
##
# @BlockdevCreateOptionsQcow2:
#
@@ -4297,6 +4312,8 @@
# allowed values: off, falloc, full, metadata)
# @lazy-refcounts True if refcounts may be updated lazily (default: off)
# @refcount-bits Width of reference counts in bits (default: 16)
+# @compression-type The image cluster compression method
+# (default: zlib, since 4.2)
#
# Since: 2.12
##
@@ -4312,7 +4329,8 @@
'*cluster-size': 'size',
'*preallocation': 'PreallocMode',
'*lazy-refcounts': 'bool',
- '*refcount-bits': 'int' } }
+ '*refcount-bits': 'int',
+ '*compression-type': 'Qcow2CompressionType' } }
##
# @BlockdevCreateOptionsQed:
--
2.17.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH v3 2/3] qcow2: rework the cluster compression routine
2019-08-19 15:00 [Qemu-devel] [PATCH v3 0/3] qcow2: add zstd cluster compression Denis Plotnikov
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 1/3] qcow2: introduce compression type feature Denis Plotnikov
@ 2019-08-19 15:00 ` Denis Plotnikov
2019-08-27 11:59 ` Vladimir Sementsov-Ogievskiy
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 3/3] qcow2: add zstd cluster compression Denis Plotnikov
2019-08-26 8:57 ` [Qemu-devel] [PATCH v3 0/3] " Denis Plotnikov
3 siblings, 1 reply; 9+ messages in thread
From: Denis Plotnikov @ 2019-08-19 15:00 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, den, qemu-block, armbru, mreitz
The patch allow to process image compression type defined
in the image header and choose an appropriate method for
image clusters (de)compression.
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
---
block/qcow2-threads.c | 78 +++++++++++++++++++++++++++++++++++--------
1 file changed, 64 insertions(+), 14 deletions(-)
diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
index 3b1e63fe41..14b5bd76fb 100644
--- a/block/qcow2-threads.c
+++ b/block/qcow2-threads.c
@@ -73,8 +73,11 @@ typedef struct Qcow2CompressData {
Qcow2CompressFunc func;
} Qcow2CompressData;
+
/*
- * qcow2_compress()
+ * qcow2_zlib_compress()
+ *
+ * Compress @src_size bytes of data using zlib compression method
*
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
@@ -83,8 +86,8 @@ typedef struct Qcow2CompressData {
* -ENOMEM destination buffer is not enough to store compressed data
* -EIO on any other error
*/
-static ssize_t qcow2_compress(void *dest, size_t dest_size,
- const void *src, size_t src_size)
+static ssize_t qcow2_zlib_compress(void *dest, size_t dest_size,
+ const void *src, size_t src_size)
{
ssize_t ret;
z_stream strm;
@@ -119,19 +122,19 @@ static ssize_t qcow2_compress(void *dest, size_t dest_size,
}
/*
- * qcow2_decompress()
+ * qcow2_zlib_decompress()
*
* Decompress some data (not more than @src_size bytes) to produce exactly
- * @dest_size bytes.
+ * @dest_size bytes using zlib compression method
*
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
*
* Returns: 0 on success
- * -1 on fail
+ * -EIO on fail
*/
-static ssize_t qcow2_decompress(void *dest, size_t dest_size,
- const void *src, size_t src_size)
+static ssize_t qcow2_zlib_decompress(void *dest, size_t dest_size,
+ const void *src, size_t src_size)
{
int ret = 0;
z_stream strm;
@@ -144,7 +147,7 @@ static ssize_t qcow2_decompress(void *dest, size_t dest_size,
ret = inflateInit2(&strm, -12);
if (ret != Z_OK) {
- return -1;
+ return -EIO;
}
ret = inflate(&strm, Z_FINISH);
@@ -154,7 +157,7 @@ static ssize_t qcow2_decompress(void *dest, size_t dest_size,
* @src buffer may be processed partly (because in qcow2 we know size of
* compressed data with precision of one sector)
*/
- ret = -1;
+ ret = -EIO;
}
inflateEnd(&strm);
@@ -189,20 +192,67 @@ qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size,
return arg.ret;
}
+/*
+ * qcow2_co_compress()
+ *
+ * Compress @src_size bytes of data using the compression
+ * method defined by the image compression type
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ * a negative error code on fail
+ */
ssize_t coroutine_fn
qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
const void *src, size_t src_size)
{
- return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
- qcow2_compress);
+ BDRVQcow2State *s = bs->opaque;
+ Qcow2CompressFunc fn;
+
+ switch (s->compression_type) {
+ case QCOW2_COMPRESSION_TYPE_ZLIB:
+ fn = qcow2_zlib_compress;
+ break;
+
+ default:
+ return -ENOTSUP;
+ }
+
+ return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
}
+/*
+ * qcow2_co_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes using the compression method defined by the image
+ * compression type
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ * a negative error code on fail
+ */
ssize_t coroutine_fn
qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
const void *src, size_t src_size)
{
- return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
- qcow2_decompress);
+ BDRVQcow2State *s = bs->opaque;
+ Qcow2CompressFunc fn;
+
+ switch (s->compression_type) {
+ case QCOW2_COMPRESSION_TYPE_ZLIB:
+ fn = qcow2_zlib_decompress;
+ break;
+
+ default:
+ return -ENOTSUP;
+ }
+
+ return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
}
--
2.17.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH v3 3/3] qcow2: add zstd cluster compression
2019-08-19 15:00 [Qemu-devel] [PATCH v3 0/3] qcow2: add zstd cluster compression Denis Plotnikov
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 1/3] qcow2: introduce compression type feature Denis Plotnikov
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 2/3] qcow2: rework the cluster compression routine Denis Plotnikov
@ 2019-08-19 15:00 ` Denis Plotnikov
2019-08-27 12:51 ` Vladimir Sementsov-Ogievskiy
2019-08-26 8:57 ` [Qemu-devel] [PATCH v3 0/3] " Denis Plotnikov
3 siblings, 1 reply; 9+ messages in thread
From: Denis Plotnikov @ 2019-08-19 15:00 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, den, qemu-block, armbru, mreitz
zstd significantly reduces cluster compression time.
It provides better compression performance maintaining
the same level of compression ratio in comparison with
zlib, which, at the moment, has been the only compression
method available.
The performance test results:
Test compresses and decompresses qemu qcow2 image with just
installed rhel-7.6 guest.
Image cluster size: 64K. Image on disk size: 2.2G
The test was conducted with brd disk to reduce the influence
of disk subsystem to the test results.
The results is given in seconds.
compress cmd:
time ./qemu-img convert -O qcow2 -c -o compression_type=[zlib|zstd]
src.img [zlib|zstd]_compressed.img
decompress cmd
time ./qemu-img convert -O qcow2
[zlib|zstd]_compressed.img uncompressed.img
compression decompression
zlib zstd zlib zstd
------------------------------------------------------------
real 65.5 16.3 (-75 %) 1.9 1.6 (-16 %)
user 65.0 15.8 5.3 2.5
sys 3.3 0.2 2.0 2.0
Both ZLIB and ZSTD gave the same compression ratio: 1.57
compressed image size in both cases: 1.4G
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
---
block/qcow2-threads.c | 94 ++++++++++++++++++++++++++++++++++++++++++
block/qcow2.c | 6 +++
configure | 34 +++++++++++++++
docs/interop/qcow2.txt | 20 +++++++++
qapi/block-core.json | 3 +-
5 files changed, 156 insertions(+), 1 deletion(-)
diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
index 14b5bd76fb..85d04e6c2e 100644
--- a/block/qcow2-threads.c
+++ b/block/qcow2-threads.c
@@ -28,6 +28,11 @@
#define ZLIB_CONST
#include <zlib.h>
+#ifdef CONFIG_ZSTD
+#include <zstd.h>
+#include <zstd_errors.h>
+#endif
+
#include "qcow2.h"
#include "block/thread-pool.h"
#include "crypto.h"
@@ -165,6 +170,85 @@ static ssize_t qcow2_zlib_decompress(void *dest, size_t dest_size,
return ret;
}
+#ifdef CONFIG_ZSTD
+/*
+ * qcow2_zstd_compress()
+ *
+ * Compress @src_size bytes of data using zstd compression method
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: compressed size on success
+ * -ENOMEM destination buffer is not enough to store compressed data
+ * -EIO on any other error
+ */
+
+static ssize_t qcow2_zstd_compress(void *dest, size_t dest_size,
+ const void *src, size_t src_size)
+{
+ ssize_t ret;
+ uint32_t *c_size = dest;
+ /* steal some bytes to store compressed chunk size */
+ char *d_buf = ((char *) dest) + sizeof(*c_size);
+
+ if (dest_size < sizeof(*c_size)) {
+ return -ENOMEM;
+ }
+
+ dest_size -= sizeof(*c_size);
+
+ ret = ZSTD_compress(d_buf, dest_size, src, src_size, 5);
+
+ if (ZSTD_isError(ret)) {
+ if (ZSTD_getErrorCode(ret) == ZSTD_error_dstSize_tooSmall) {
+ return -ENOMEM;
+ } else {
+ return -EIO;
+ }
+ }
+
+ /* store the compressed chunk size in the very beginning of the buffer */
+ *c_size = ret;
+
+ return ret + sizeof(*c_size);
+}
+
+/*
+ * qcow2_zstd_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes using zstd compression method
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ * -EIO on any error
+ */
+
+static ssize_t qcow2_zstd_decompress(void *dest, size_t dest_size,
+ const void *src, size_t src_size)
+{
+ ssize_t ret;
+ /*
+ * zstd decompress wants to know the exact length of the data
+ * for that purpose, on the compression the length is stored in
+ * the very beginning of the compressed buffer
+ */
+ const uint32_t *s_size = src;
+ const char *s_buf = ((const char *) src) + sizeof(*s_size);
+
+ ret = ZSTD_decompress(dest, dest_size, s_buf, *s_size);
+
+ if (ZSTD_isError(ret)) {
+ return -EIO;
+ }
+
+ return 0;
+}
+#endif
+
static int qcow2_compress_pool_func(void *opaque)
{
Qcow2CompressData *data = opaque;
@@ -216,6 +300,11 @@ qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
fn = qcow2_zlib_compress;
break;
+#ifdef CONFIG_ZSTD
+ case QCOW2_COMPRESSION_TYPE_ZSTD:
+ fn = qcow2_zstd_compress;
+ break;
+#endif
default:
return -ENOTSUP;
}
@@ -248,6 +337,11 @@ qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
fn = qcow2_zlib_decompress;
break;
+#ifdef CONFIG_ZSTD
+ case QCOW2_COMPRESSION_TYPE_ZSTD:
+ fn = qcow2_zstd_decompress;
+ break;
+#endif
default:
return -ENOTSUP;
}
diff --git a/block/qcow2.c b/block/qcow2.c
index 4e07b7e9ec..dfb7b52033 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1201,6 +1201,9 @@ static int check_compression_type(BDRVQcow2State *s, Error **errp)
{
switch (s->compression_type) {
case QCOW2_COMPRESSION_TYPE_ZLIB:
+#ifdef CONFIG_ZSTD
+ case QCOW2_COMPRESSION_TYPE_ZSTD:
+#endif
break;
default:
@@ -3294,6 +3297,9 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
switch (qcow2_opts->compression_type) {
case QCOW2_COMPRESSION_TYPE_ZLIB:
+#ifdef CONFIG_ZSTD
+ case QCOW2_COMPRESSION_TYPE_ZSTD:
+#endif
break;
default:
diff --git a/configure b/configure
index 714e7fb6a1..111c34878d 100755
--- a/configure
+++ b/configure
@@ -441,6 +441,7 @@ opengl_dmabuf="no"
cpuid_h="no"
avx2_opt=""
zlib="yes"
+zstd=""
capstone=""
lzo=""
snappy=""
@@ -1358,6 +1359,10 @@ for opt do
;;
--disable-lzfse) lzfse="no"
;;
+ --enable-zstd) zstd="yes"
+ ;;
+ --disable-zstd) zstd="no"
+ ;;
--enable-guest-agent) guest_agent="yes"
;;
--disable-guest-agent) guest_agent="no"
@@ -1812,6 +1817,7 @@ disabled with --disable-FEATURE, default is enabled if available:
(for reading bzip2-compressed dmg images)
lzfse support of lzfse compression library
(for reading lzfse-compressed dmg images)
+ zstd support of zstd compression library
seccomp seccomp support
coroutine-pool coroutine freelist (better performance)
glusterfs GlusterFS backend
@@ -2407,6 +2413,30 @@ EOF
fi
fi
+#########################################
+# zstd check
+
+if test "$zstd" == "yes" ; then
+ if $pkg_config --exists libzstd; then
+ zstd_cflags=$($pkg_config --cflags libzstd)
+ zstd_libs=$($pkg_config --libs libzstd)
+ QEMU_CFLAGS="$zstd_cflags $QEMU_CFLAGS"
+ LIBS="$zstd_libs $LIBS"
+ else
+ cat > $TMPC << EOF
+#include <zstd.h>
+int main(void) { ZSTD_versionNumber(); return 0; }
+EOF
+ if compile_prog "" "-lzstd" ; then
+ LIBS="$LIBS -lzstd"
+ else
+ feature_not_found "zstd" "Install libzstd-devel"
+ fi
+ fi
+else
+ zstd="no"
+fi
+
##########################################
# libseccomp check
@@ -6460,6 +6490,7 @@ echo "lzo support $lzo"
echo "snappy support $snappy"
echo "bzip2 support $bzip2"
echo "lzfse support $lzfse"
+echo "zstd support $zstd"
echo "NUMA host support $numa"
echo "libxml2 $libxml2"
echo "tcmalloc support $tcmalloc"
@@ -7306,6 +7337,9 @@ fi
if test "$sheepdog" = "yes" ; then
echo "CONFIG_SHEEPDOG=y" >> $config_host_mak
fi
+if test "$zstd" = "yes" ; then
+ echo "CONFIG_ZSTD=y" >> $config_host_mak
+fi
if test "$tcg_interpreter" = "yes"; then
QEMU_INCLUDES="-iquote \$(SRC_PATH)/tcg/tci $QEMU_INCLUDES"
diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
index e1be8bd5c3..4b0dc124f5 100644
--- a/docs/interop/qcow2.txt
+++ b/docs/interop/qcow2.txt
@@ -181,6 +181,7 @@ in the description of a field.
must be set.
Available compression type values:
0: zlib <https://www.zlib.net/> (default)
+ 1: zstd <http://github.com/facebook/zstd>
Directly after the image header, optional sections called header extensions can
be stored. Each extension has a structure like the following:
@@ -536,6 +537,9 @@ Compressed Clusters Descriptor (x = 62 - (cluster_bits - 8)):
Another compressed cluster may map to the tail of the final
sector used by this compressed cluster.
+ The layout of the compressed data depends on the compression
+ type used for the image (see compressed cluster layout).
+
If a cluster is unallocated, read requests shall read the data from the backing
file (except if bit 0 in the Standard Cluster Descriptor is set). If there is
no backing file or the backing file is smaller than the image, they shall read
@@ -788,3 +792,19 @@ In the image file the 'enabled' state is reflected by the 'auto' flag. If this
flag is set, the software must consider the bitmap as 'enabled' and start
tracking virtual disk changes to this bitmap from the first write to the
virtual disk. If this flag is not set then the bitmap is disabled.
+
+=== Compressed cluster layout ===
+
+The compressed cluster data may have a different layout depending on the
+compression type used for the image, and store specific data for the particular
+compression type.
+
+Compressed data layout for the available compression types:
+(x = data_space_length - 1)
+
+ zlib <http://zlib.net/>:
+ Byte 0 - x: the compressed data content
+ all the space provided used for compressed data
+ zstd <http://github.com/facebook/zstd>:
+ Byte 0 - 3: the length of compressed data
+ 4 - x: the compressed data content
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 2c002ca6a9..9e458d5b40 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -4283,11 +4283,12 @@
# Compression type used in qcow2 image file
#
# @zlib: zlib compression, see <http://zlib.net/>
+# @zstd: zstd compression, see <http://github.com/facebook/zstd>
#
# Since: 4.2
##
{ 'enum': 'Qcow2CompressionType',
- 'data': [ 'zlib' ] }
+ 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] }
##
# @BlockdevCreateOptionsQcow2:
--
2.17.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v3 0/3] qcow2: add zstd cluster compression
2019-08-19 15:00 [Qemu-devel] [PATCH v3 0/3] qcow2: add zstd cluster compression Denis Plotnikov
` (2 preceding siblings ...)
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 3/3] qcow2: add zstd cluster compression Denis Plotnikov
@ 2019-08-26 8:57 ` Denis Plotnikov
3 siblings, 0 replies; 9+ messages in thread
From: Denis Plotnikov @ 2019-08-26 8:57 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, Vladimir Sementsov-Ogievskiy, Denis Lunev, qemu-block,
armbru, mreitz
Ping!
On 19.08.2019 18:00, Denis Plotnikov wrote:
> v3:
> * relax the compression type setting requirement when
> the compression type is not zlib [Eric, Kevin]
> * add compression type values to the spec [Eric]
> * fix wording in the spec and descriptions [Eric]
> * fix functions descriptions [Max]
> * fix zstd (de)compression functions flaws [Max]
> * fix zstd related parts of configure file [Max]
> * rebased to v4.1.0-rc5 and chenged the series version aiming to 4.2
>
> v2:
> * relax the compression type setting restriction in the spec
> * fix qcow2 header size checking
> * fix error processing and messaging
> * fix qcow2 image specific info reporting
> * set Qcow2CompressionType zstd config dependant
> * add zstd compressed cluster format description to the spec
>
> v1:
> * extend qcow2 header instead of adding a new incompatible extension header
> specification re-written accordingly
> * enable zstd compression via config
> * fix zstd (de)compression functions
> * fix comments/description
> * fix function naming
>
> ---
> The goal of the patch-set is to enable qcow2 to use zstd compression for
> clusters. ZSTD provides better (de)compression performance than currently
> used ZLIB. Using it will improve perforamnce (reduce compression time)
> when the compressed clusters is used, e.g backup scenarios.
>
> Also, the patch-set extends qcow2 specification by adding compression_type
> feature. The feature enables adding ZSTD and another compression algorithms
> in the future.
>
> Here is some measurements ZSTD vs ZLIB:
>
> The test:
> Test compresses and decompresses qemu qcow2 image with just
> installed rhel-7.6 guest.
> Image cluster size: 64K. Image on disk size: 2.2G
>
> The test was conducted with brd disk to reduce the influence
> of disk subsystem to the test results.
> The results is given in seconds.
>
> compress cmd:
> time ./qemu-img convert -O qcow2 -c -o compression_type=[zlib|zstd]
> src.img [zlib|zstd]_compressed.img
> decompress cmd
> time ./qemu-img convert -O qcow2
> [zlib|zstd]_compressed.img uncompressed.img
>
>
> The results:
> compression decompression
> zlib zstd zlib zstd
> ------------------------------------------------------------
> real 65.5 16.3 (-75 %) 1.9 1.6 (-16 %)
> user 65.0 15.8 5.3 2.5
> sys 3.3 0.2 2.0 2.0
>
> Both ZLIB and ZSTD gave the same compression ratio: ~1.5
> compressed image size in both cases: ~1.4G
>
> Denis Plotnikov (3):
> qcow2: introduce compression type feature
> qcow2: rework the cluster compression routine
> qcow2: add zstd cluster compression
>
> block/qcow2-threads.c | 172 ++++++++++++++++++++++++++++++++++----
> block/qcow2.c | 100 ++++++++++++++++++++++
> block/qcow2.h | 26 ++++--
> configure | 34 ++++++++
> docs/interop/qcow2.txt | 39 ++++++++-
> include/block/block_int.h | 1 +
> qapi/block-core.json | 23 ++++-
> 7 files changed, 371 insertions(+), 24 deletions(-)
>
--
Best,
Denis
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v3 1/3] qcow2: introduce compression type feature
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 1/3] qcow2: introduce compression type feature Denis Plotnikov
@ 2019-08-27 11:49 ` Vladimir Sementsov-Ogievskiy
2019-08-27 14:52 ` Denis Plotnikov
0 siblings, 1 reply; 9+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2019-08-27 11:49 UTC (permalink / raw)
To: Denis Plotnikov, qemu-devel
Cc: kwolf, Denis Lunev, qemu-block, armbru, mreitz
19.08.2019 18:00, Denis Plotnikov wrote:
> The patch adds some preparation parts for incompatible compression type
> feature to QCOW2 header that indicates that *all* compressed clusters
> must be (de)compressed using a certain compression type.
>
> 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.
>
> The goal of the feature is to add support of other compression algorithms
> to qcow2. For example, ZSTD which is more effective on compression than ZLIB.
> It works roughly 2x faster than ZLIB providing a comparable compression ratio
> and therefore provides a performance advantage in backup scenarios.
>
> The default compression is ZLIB. Images created with ZLIB compression type
> are backward compatible with older qemu versions.
>
> Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
> ---
> block/qcow2.c | 94 +++++++++++++++++++++++++++++++++++++++
> block/qcow2.h | 26 ++++++++---
> docs/interop/qcow2.txt | 19 +++++++-
> include/block/block_int.h | 1 +
> qapi/block-core.json | 22 ++++++++-
> 5 files changed, 152 insertions(+), 10 deletions(-)
>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 039bdc2f7e..4e07b7e9ec 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1197,6 +1197,32 @@ static int qcow2_update_options(BlockDriverState *bs, QDict *options,
> return ret;
> }
>
> +static int check_compression_type(BDRVQcow2State *s, Error **errp)
> +{
> + switch (s->compression_type) {
> + case QCOW2_COMPRESSION_TYPE_ZLIB:
> + break;
> +
> + default:
> + error_setg(errp, "qcow2: unknown compression type: %u",
> + s->compression_type);
> + return -ENOTSUP;
> + }
> +
> + /*
> + * if the compression type differs from QCOW2_COMPRESSION_TYPE_ZLIB
> + * the incompatible feature flag must be set
> + */
> +
> + if (s->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB &&
> + !(s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION_TYPE)) {
> + error_setg(errp, "qcow2: Invalid compression type setting");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> /* Called with s->lock held. */
> static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
> int flags, Error **errp)
> @@ -1312,6 +1338,35 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
> s->compatible_features = header.compatible_features;
> s->autoclear_features = header.autoclear_features;
>
> + /*
> + * Handle compression type
> + * Older qcow2 images don't contain the compression type header.
> + * Distinguish them by the header length and use
> + * the only valid (default) compression type in that case
> + */
> + if (header.header_length > offsetof(QCowHeader, compression_type)) {
> + /* sanity check that we can read a compression type */
> + size_t min_len = offsetof(QCowHeader, compression_type) +
> + sizeof(header.compression_type);
> + if (header.header_length < min_len) {
> + error_setg(errp,
> + "Could not read compression type, "
> + "qcow2 header is too short");
> + ret = -EINVAL;
> + goto fail;
> + }
> +
> + header.compression_type = be32_to_cpu(header.compression_type);
> + s->compression_type = header.compression_type;
> + } else {
> + s->compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
> + }
> +
> + ret = check_compression_type(s, errp);
> + if (ret) {
> + goto fail;
> + }
> +
> if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
> void *feature_table = NULL;
> qcow2_read_extensions(bs, header.header_length, ext_end,
> @@ -2516,6 +2571,12 @@ int qcow2_update_header(BlockDriverState *bs)
> total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
> refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
>
> + ret = check_compression_type(s, NULL);
> +
> + if (ret) {
> + goto fail;
> + }
> +
> *header = (QCowHeader) {
> /* Version 2 fields */
> .magic = cpu_to_be32(QCOW_MAGIC),
> @@ -2538,6 +2599,7 @@ int qcow2_update_header(BlockDriverState *bs)
> .autoclear_features = cpu_to_be64(s->autoclear_features),
> .refcount_order = cpu_to_be32(s->refcount_order),
> .header_length = cpu_to_be32(header_length),
> + .compression_type = cpu_to_be32(s->compression_type),
> };
>
> /* For older versions, write a shorter header */
> @@ -2635,6 +2697,11 @@ int qcow2_update_header(BlockDriverState *bs)
> .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
> .name = "lazy refcounts",
> },
> + {
> + .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
> + .bit = QCOW2_INCOMPAT_COMPRESSION_TYPE_BITNR,
> + .name = "compression type",
> + },
> };
>
> ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
> @@ -3202,6 +3269,7 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
> .refcount_table_offset = cpu_to_be64(cluster_size),
> .refcount_table_clusters = cpu_to_be32(1),
> .refcount_order = cpu_to_be32(refcount_order),
> + .compression_type = cpu_to_be32(QCOW2_COMPRESSION_TYPE_ZLIB),
> .header_length = cpu_to_be32(sizeof(*header)),
> };
>
> @@ -3221,6 +3289,24 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
> cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW);
> }
>
> + if (qcow2_opts->has_compression_type &&
> + qcow2_opts->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) {
> +
> + switch (qcow2_opts->compression_type) {
> + case QCOW2_COMPRESSION_TYPE_ZLIB:
a bit confusing, as it's unreachable because of if (), and because if we are here we are going to
do a wrong thing: to set incompatible feature (so, I firstly thought that this is a bug and then
looked above at if() condition)
> + break;
> +
> + default:
> + error_setg_errno(errp, -EINVAL, "Unknown compression type");
> + goto out;
> + }
> +
> + header->compression_type = cpu_to_be32(qcow2_opts->compression_type);
> +
> + header->incompatible_features |=
> + cpu_to_be64(QCOW2_INCOMPAT_COMPRESSION_TYPE);
cpu_to_be32 actually
> + }
> +
> ret = blk_pwrite(blk, 0, header, cluster_size, 0);
> g_free(header);
> if (ret < 0) {
> @@ -3402,6 +3488,7 @@ static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opt
> { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
> { BLOCK_OPT_COMPAT_LEVEL, "version" },
> { BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" },
> + { BLOCK_OPT_COMPRESSION_TYPE, "compression-type" },
I think we don't need it. This array is commented as:
/* Change legacy command line options into QMP ones */
but compression-type is not a legacy option, it's a new one. Why to tolerate old notation for it?
> { NULL, NULL },
> };
>
> @@ -4598,6 +4685,7 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs,
> .data_file = g_strdup(s->image_data_file),
> .has_data_file_raw = has_data_file(bs),
> .data_file_raw = data_file_is_raw(bs),
> + .compression_type = s->compression_type,
> };
> } else {
> /* if this assertion fails, this probably means a new version was
> @@ -5163,6 +5251,12 @@ static QemuOptsList qcow2_create_opts = {
> .help = "Width of a reference count entry in bits",
> .def_value_str = "16"
> },
> + {
> + .name = BLOCK_OPT_COMPRESSION_TYPE,
> + .type = QEMU_OPT_STRING,
> + .help = "Compression method used for image clusters compression",
> + .def_value_str = "zlib"
> + },
> { /* end of list */ }
> }
> };
> diff --git a/block/qcow2.h b/block/qcow2.h
> index fc1b0d3c1e..9a241e4b9a 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -140,6 +140,7 @@ typedef struct QCowHeader {
>
> uint32_t refcount_order;
> uint32_t header_length;
> + uint32_t compression_type;
> } QEMU_PACKED QCowHeader;
>
> typedef struct QEMU_PACKED QCowSnapshotHeader {
> @@ -203,16 +204,20 @@ enum {
>
> /* Incompatible feature bits */
> enum {
> - QCOW2_INCOMPAT_DIRTY_BITNR = 0,
> - QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
> - QCOW2_INCOMPAT_DATA_FILE_BITNR = 2,
> - 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_DIRTY_BITNR = 0,
> + QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
> + QCOW2_INCOMPAT_DATA_FILE_BITNR = 2,
> + QCOW2_INCOMPAT_COMPRESSION_TYPE_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_TYPE =
> + 1 << QCOW2_INCOMPAT_COMPRESSION_TYPE_BITNR,
>
> QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY
> | QCOW2_INCOMPAT_CORRUPT
> - | QCOW2_INCOMPAT_DATA_FILE,
> + | QCOW2_INCOMPAT_DATA_FILE
> + | QCOW2_INCOMPAT_COMPRESSION_TYPE,
> };
>
> /* Compatible feature bits */
> @@ -359,6 +364,13 @@ 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.
> + * The only way to change the compression type is to convert the image
> + * with the desired compression type set
> + */
> + uint32_t compression_type;
> } BDRVQcow2State;
>
> typedef struct Qcow2COWRegion {
> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
> index af5711e533..e1be8bd5c3 100644
> --- a/docs/interop/qcow2.txt
> +++ b/docs/interop/qcow2.txt
> @@ -109,7 +109,12 @@ in the description of a field.
> An External Data File Name header extension may
> be present if this bit is set.
>
> - Bits 3-63: Reserved (set to 0)
> + Bit 3: Compression type bit. The bit must be set if
> + the compression type differs from default of zlib.
> + If the compression type is default the bit should
> + be unset.
> +
> + Bits 4-63: Reserved (set to 0)
>
> 80 - 87: compatible_features
> Bitmask of compatible features. An implementation can
> @@ -165,6 +170,18 @@ in the description of a field.
> Length of the header structure in bytes. For version 2
> images, the length is always assumed to be 72 bytes.
>
> + 104 - 107: compression_type
Why 4 bytes? 1 is enough and 2 are enough for sure. Or we need to align all fields to 4 bytes?
> + Defines the compression method used for compressed clusters.
> + A single compression type is applied to all compressed image
> + clusters.
> + The compression type is set on image creation only.
this sentence is not needed, why to abandon inplace conversion? And anyway, it's not
about specification of format.
> + The default compression type is zlib (value: 0).
> + When the compression type differs from the default
> + the compression type bit (incompatible feature bit 3)
> + must be set.
> + Available compression type values:
> + 0: zlib <https://www.zlib.net/> (default)
> +
> Directly after the image header, optional sections called header extensions can
> be stored. Each extension has a structure like the following:
>
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 3aa1e832a8..4b254802e5 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -58,6 +58,7 @@
> #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
> #define BLOCK_OPT_DATA_FILE "data_file"
> #define BLOCK_OPT_DATA_FILE_RAW "data_file_raw"
> +#define BLOCK_OPT_COMPRESSION_TYPE "compression_type"
>
> #define BLOCK_PROBE_BUF_SIZE 512
>
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 0d43d4f37c..2c002ca6a9 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -78,6 +78,8 @@
> #
> # @bitmaps: A list of qcow2 bitmap details (since 4.0)
> #
> +# @compression-type: the image cluster compression method (since 4.2)
> +#
> # Since: 1.7
> ##
> { 'struct': 'ImageInfoSpecificQCow2',
> @@ -89,7 +91,8 @@
> '*corrupt': 'bool',
> 'refcount-bits': 'int',
> '*encrypt': 'ImageInfoSpecificQCow2Encryption',
> - '*bitmaps': ['Qcow2BitmapInfo']
> + '*bitmaps': ['Qcow2BitmapInfo'],
> + 'compression-type': 'Qcow2CompressionType'
> } }
>
> ##
> @@ -4274,6 +4277,18 @@
> 'data': [ 'v2', 'v3' ] }
>
>
> +##
> +# @Qcow2CompressionType:
> +#
> +# Compression type used in qcow2 image file
> +#
> +# @zlib: zlib compression, see <http://zlib.net/>
> +#
> +# Since: 4.2
> +##
> +{ 'enum': 'Qcow2CompressionType',
> + 'data': [ 'zlib' ] }
> +
> ##
> # @BlockdevCreateOptionsQcow2:
> #
> @@ -4297,6 +4312,8 @@
> # allowed values: off, falloc, full, metadata)
> # @lazy-refcounts True if refcounts may be updated lazily (default: off)
> # @refcount-bits Width of reference counts in bits (default: 16)
> +# @compression-type The image cluster compression method
> +# (default: zlib, since 4.2)
> #
> # Since: 2.12
> ##
> @@ -4312,7 +4329,8 @@
> '*cluster-size': 'size',
> '*preallocation': 'PreallocMode',
> '*lazy-refcounts': 'bool',
> - '*refcount-bits': 'int' } }
> + '*refcount-bits': 'int',
> + '*compression-type': 'Qcow2CompressionType' } }
>
> ##
> # @BlockdevCreateOptionsQed:
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v3 2/3] qcow2: rework the cluster compression routine
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 2/3] qcow2: rework the cluster compression routine Denis Plotnikov
@ 2019-08-27 11:59 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 9+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2019-08-27 11:59 UTC (permalink / raw)
To: Denis Plotnikov, qemu-devel
Cc: kwolf, Denis Lunev, qemu-block, armbru, mreitz
19.08.2019 18:00, Denis Plotnikov wrote:
> The patch allow to process image compression type defined
> in the image header and choose an appropriate method for
> image clusters (de)compression.
>
> Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
> ---
> block/qcow2-threads.c | 78 +++++++++++++++++++++++++++++++++++--------
> 1 file changed, 64 insertions(+), 14 deletions(-)
>
> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
> index 3b1e63fe41..14b5bd76fb 100644
> --- a/block/qcow2-threads.c
> +++ b/block/qcow2-threads.c
> @@ -73,8 +73,11 @@ typedef struct Qcow2CompressData {
> Qcow2CompressFunc func;
> } Qcow2CompressData;
>
> +
> /*
> - * qcow2_compress()
> + * qcow2_zlib_compress()
> + *
> + * Compress @src_size bytes of data using zlib compression method
> *
> * @dest - destination buffer, @dest_size bytes
> * @src - source buffer, @src_size bytes
> @@ -83,8 +86,8 @@ typedef struct Qcow2CompressData {
> * -ENOMEM destination buffer is not enough to store compressed data
> * -EIO on any other error
> */
> -static ssize_t qcow2_compress(void *dest, size_t dest_size,
> - const void *src, size_t src_size)
> +static ssize_t qcow2_zlib_compress(void *dest, size_t dest_size,
> + const void *src, size_t src_size)
> {
> ssize_t ret;
> z_stream strm;
> @@ -119,19 +122,19 @@ static ssize_t qcow2_compress(void *dest, size_t dest_size,
> }
>
> /*
> - * qcow2_decompress()
> + * qcow2_zlib_decompress()
> *
> * Decompress some data (not more than @src_size bytes) to produce exactly
> - * @dest_size bytes.
> + * @dest_size bytes using zlib compression method
> *
> * @dest - destination buffer, @dest_size bytes
> * @src - source buffer, @src_size bytes
> *
> * Returns: 0 on success
> - * -1 on fail
> + * -EIO on fail
> */
> -static ssize_t qcow2_decompress(void *dest, size_t dest_size,
> - const void *src, size_t src_size)
> +static ssize_t qcow2_zlib_decompress(void *dest, size_t dest_size,
> + const void *src, size_t src_size)
> {
> int ret = 0;
> z_stream strm;
> @@ -144,7 +147,7 @@ static ssize_t qcow2_decompress(void *dest, size_t dest_size,
>
> ret = inflateInit2(&strm, -12);
> if (ret != Z_OK) {
> - return -1;
> + return -EIO;
> }
>
> ret = inflate(&strm, Z_FINISH);
> @@ -154,7 +157,7 @@ static ssize_t qcow2_decompress(void *dest, size_t dest_size,
> * @src buffer may be processed partly (because in qcow2 we know size of
> * compressed data with precision of one sector)
> */
> - ret = -1;
> + ret = -EIO;
> }
>
> inflateEnd(&strm);
> @@ -189,20 +192,67 @@ qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size,
> return arg.ret;
> }
>
> +/*
> + * qcow2_co_compress()
> + *
> + * Compress @src_size bytes of data using the compression
> + * method defined by the image compression type
> + *
> + * @dest - destination buffer, @dest_size bytes
> + * @src - source buffer, @src_size bytes
> + *
> + * Returns: 0 on success
> + * a negative error code on fail
> + */
> ssize_t coroutine_fn
> qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
> const void *src, size_t src_size)
> {
> - return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
> - qcow2_compress);
> + BDRVQcow2State *s = bs->opaque;
> + Qcow2CompressFunc fn;
> +
> + switch (s->compression_type) {
> + case QCOW2_COMPRESSION_TYPE_ZLIB:
> + fn = qcow2_zlib_compress;
> + break;
> +
> + default:
> + return -ENOTSUP;
it may be g_assert_not_reached() instead, as we never set state field to unsupported value.
> + }
> +
> + return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
> }
>
> +/*
> + * qcow2_co_decompress()
> + *
> + * Decompress some data (not more than @src_size bytes) to produce exactly
> + * @dest_size bytes using the compression method defined by the image
> + * compression type
> + *
> + * @dest - destination buffer, @dest_size bytes
> + * @src - source buffer, @src_size bytes
> + *
> + * Returns: 0 on success
> + * a negative error code on fail
> + */
> ssize_t coroutine_fn
> qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
> const void *src, size_t src_size)
> {
> - return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
> - qcow2_decompress);
> + BDRVQcow2State *s = bs->opaque;
> + Qcow2CompressFunc fn;
> +
> + switch (s->compression_type) {
> + case QCOW2_COMPRESSION_TYPE_ZLIB:
> + fn = qcow2_zlib_decompress;
> + break;
> +
> + default:
> + return -ENOTSUP;
and here, and may be in previous patch (where call switch on s->compression_type)
But anyway, with this changed or without:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> + }
> +
> + return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
> }
>
>
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v3 3/3] qcow2: add zstd cluster compression
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 3/3] qcow2: add zstd cluster compression Denis Plotnikov
@ 2019-08-27 12:51 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 9+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2019-08-27 12:51 UTC (permalink / raw)
To: Denis Plotnikov, qemu-devel
Cc: kwolf, Denis Lunev, qemu-block, armbru, mreitz
19.08.2019 18:00, Denis Plotnikov wrote:
> zstd significantly reduces cluster compression time.
> It provides better compression performance maintaining
> the same level of compression ratio in comparison with
> zlib, which, at the moment, has been the only compression
> method available.
>
> The performance test results:
> Test compresses and decompresses qemu qcow2 image with just
> installed rhel-7.6 guest.
> Image cluster size: 64K. Image on disk size: 2.2G
>
> The test was conducted with brd disk to reduce the influence
> of disk subsystem to the test results.
> The results is given in seconds.
>
> compress cmd:
> time ./qemu-img convert -O qcow2 -c -o compression_type=[zlib|zstd]
> src.img [zlib|zstd]_compressed.img
> decompress cmd
> time ./qemu-img convert -O qcow2
> [zlib|zstd]_compressed.img uncompressed.img
>
> compression decompression
> zlib zstd zlib zstd
> ------------------------------------------------------------
> real 65.5 16.3 (-75 %) 1.9 1.6 (-16 %)
> user 65.0 15.8 5.3 2.5
> sys 3.3 0.2 2.0 2.0
>
> Both ZLIB and ZSTD gave the same compression ratio: 1.57
> compressed image size in both cases: 1.4G
>
> Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
> ---
> block/qcow2-threads.c | 94 ++++++++++++++++++++++++++++++++++++++++++
> block/qcow2.c | 6 +++
> configure | 34 +++++++++++++++
> docs/interop/qcow2.txt | 20 +++++++++
> qapi/block-core.json | 3 +-
> 5 files changed, 156 insertions(+), 1 deletion(-)
>
> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
> index 14b5bd76fb..85d04e6c2e 100644
> --- a/block/qcow2-threads.c
> +++ b/block/qcow2-threads.c
> @@ -28,6 +28,11 @@
> #define ZLIB_CONST
> #include <zlib.h>
>
> +#ifdef CONFIG_ZSTD
> +#include <zstd.h>
> +#include <zstd_errors.h>
> +#endif
> +
> #include "qcow2.h"
> #include "block/thread-pool.h"
> #include "crypto.h"
> @@ -165,6 +170,85 @@ static ssize_t qcow2_zlib_decompress(void *dest, size_t dest_size,
> return ret;
> }
>
> +#ifdef CONFIG_ZSTD
> +/*
> + * qcow2_zstd_compress()
> + *
> + * Compress @src_size bytes of data using zstd compression method
> + *
> + * @dest - destination buffer, @dest_size bytes
> + * @src - source buffer, @src_size bytes
> + *
> + * Returns: compressed size on success
> + * -ENOMEM destination buffer is not enough to store compressed data
> + * -EIO on any other error
> + */
> +
> +static ssize_t qcow2_zstd_compress(void *dest, size_t dest_size,
> + const void *src, size_t src_size)
> +{
> + ssize_t ret;
> + uint32_t *c_size = dest;
> + /* steal some bytes to store compressed chunk size */
> + char *d_buf = ((char *) dest) + sizeof(*c_size);
> +
> + if (dest_size < sizeof(*c_size)) {
> + return -ENOMEM;
> + }
> +
> + dest_size -= sizeof(*c_size);
> +
> + ret = ZSTD_compress(d_buf, dest_size, src, src_size, 5);
Let's call this "5" to be something like QCOW2_DEFAUTLT_ZSTD_COMPRESSION_LEVEL, we'll
possibly want to add an option for this in future.
> +
> + if (ZSTD_isError(ret)) {
> + if (ZSTD_getErrorCode(ret) == ZSTD_error_dstSize_tooSmall) {
> + return -ENOMEM;
> + } else {
> + return -EIO;
> + }
> + }
> +
> + /* store the compressed chunk size in the very beginning of the buffer */
> + *c_size = ret;
> +
> + return ret + sizeof(*c_size);
> +}
> +
> +/*
> + * qcow2_zstd_decompress()
> + *
> + * Decompress some data (not more than @src_size bytes) to produce exactly
> + * @dest_size bytes using zstd compression method
> + *
> + * @dest - destination buffer, @dest_size bytes
> + * @src - source buffer, @src_size bytes
> + *
> + * Returns: 0 on success
> + * -EIO on any error
> + */
> +
> +static ssize_t qcow2_zstd_decompress(void *dest, size_t dest_size,
> + const void *src, size_t src_size)
> +{
> + ssize_t ret;
> + /*
> + * zstd decompress wants to know the exact length of the data
> + * for that purpose, on the compression the length is stored in
> + * the very beginning of the compressed buffer
> + */
> + const uint32_t *s_size = src;
> + const char *s_buf = ((const char *) src) + sizeof(*s_size);
but what if *s_size (or even src_size) is corrupted? I think we need to check it before calling
ZSTD_decompress:
if (src_size < sizeof(*s_size) || src_size - sizeof(*s_size) < *s_size) {
return -EIO;
}
with this (and optionally with QCOW2_DEFAUTLT_ZSTD_COMPRESSION_LEVEL):
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> +
> + ret = ZSTD_decompress(dest, dest_size, s_buf, *s_size);
> +
> + if (ZSTD_isError(ret)) {
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +#endif
> +
[...]
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH v3 1/3] qcow2: introduce compression type feature
2019-08-27 11:49 ` Vladimir Sementsov-Ogievskiy
@ 2019-08-27 14:52 ` Denis Plotnikov
0 siblings, 0 replies; 9+ messages in thread
From: Denis Plotnikov @ 2019-08-27 14:52 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-devel
Cc: kwolf, Denis Lunev, qemu-block, armbru, mreitz
On 27.08.2019 14:49, Vladimir Sementsov-Ogievskiy wrote:
> 19.08.2019 18:00, Denis Plotnikov wrote:
>> The patch adds some preparation parts for incompatible compression type
>> feature to QCOW2 header that indicates that *all* compressed clusters
>> must be (de)compressed using a certain compression type.
>>
>> 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.
>>
>> The goal of the feature is to add support of other compression algorithms
>> to qcow2. For example, ZSTD which is more effective on compression than ZLIB.
>> It works roughly 2x faster than ZLIB providing a comparable compression ratio
>> and therefore provides a performance advantage in backup scenarios.
>>
>> The default compression is ZLIB. Images created with ZLIB compression type
>> are backward compatible with older qemu versions.
>>
>> Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
>> ---
>> block/qcow2.c | 94 +++++++++++++++++++++++++++++++++++++++
>> block/qcow2.h | 26 ++++++++---
>> docs/interop/qcow2.txt | 19 +++++++-
>> include/block/block_int.h | 1 +
>> qapi/block-core.json | 22 ++++++++-
>> 5 files changed, 152 insertions(+), 10 deletions(-)
>>
>> diff --git a/block/qcow2.c b/block/qcow2.c
>> index 039bdc2f7e..4e07b7e9ec 100644
>> --- a/block/qcow2.c
>> +++ b/block/qcow2.c
>> @@ -1197,6 +1197,32 @@ static int qcow2_update_options(BlockDriverState *bs, QDict *options,
>> return ret;
>> }
>>
>> +static int check_compression_type(BDRVQcow2State *s, Error **errp)
>> +{
>> + switch (s->compression_type) {
>> + case QCOW2_COMPRESSION_TYPE_ZLIB:
>> + break;
>> +
>> + default:
>> + error_setg(errp, "qcow2: unknown compression type: %u",
>> + s->compression_type);
>> + return -ENOTSUP;
>> + }
>> +
>> + /*
>> + * if the compression type differs from QCOW2_COMPRESSION_TYPE_ZLIB
>> + * the incompatible feature flag must be set
>> + */
>> +
>> + if (s->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB &&
>> + !(s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION_TYPE)) {
>> + error_setg(errp, "qcow2: Invalid compression type setting");
>> + return -EINVAL;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> /* Called with s->lock held. */
>> static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
>> int flags, Error **errp)
>> @@ -1312,6 +1338,35 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
>> s->compatible_features = header.compatible_features;
>> s->autoclear_features = header.autoclear_features;
>>
>> + /*
>> + * Handle compression type
>> + * Older qcow2 images don't contain the compression type header.
>> + * Distinguish them by the header length and use
>> + * the only valid (default) compression type in that case
>> + */
>> + if (header.header_length > offsetof(QCowHeader, compression_type)) {
>> + /* sanity check that we can read a compression type */
>> + size_t min_len = offsetof(QCowHeader, compression_type) +
>> + sizeof(header.compression_type);
>> + if (header.header_length < min_len) {
>> + error_setg(errp,
>> + "Could not read compression type, "
>> + "qcow2 header is too short");
>> + ret = -EINVAL;
>> + goto fail;
>> + }
>> +
>> + header.compression_type = be32_to_cpu(header.compression_type);
>> + s->compression_type = header.compression_type;
>> + } else {
>> + s->compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
>> + }
>> +
>> + ret = check_compression_type(s, errp);
>> + if (ret) {
>> + goto fail;
>> + }
>> +
>> if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
>> void *feature_table = NULL;
>> qcow2_read_extensions(bs, header.header_length, ext_end,
>> @@ -2516,6 +2571,12 @@ int qcow2_update_header(BlockDriverState *bs)
>> total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
>> refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
>>
>> + ret = check_compression_type(s, NULL);
>> +
>> + if (ret) {
>> + goto fail;
>> + }
>> +
>> *header = (QCowHeader) {
>> /* Version 2 fields */
>> .magic = cpu_to_be32(QCOW_MAGIC),
>> @@ -2538,6 +2599,7 @@ int qcow2_update_header(BlockDriverState *bs)
>> .autoclear_features = cpu_to_be64(s->autoclear_features),
>> .refcount_order = cpu_to_be32(s->refcount_order),
>> .header_length = cpu_to_be32(header_length),
>> + .compression_type = cpu_to_be32(s->compression_type),
>> };
>>
>> /* For older versions, write a shorter header */
>> @@ -2635,6 +2697,11 @@ int qcow2_update_header(BlockDriverState *bs)
>> .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
>> .name = "lazy refcounts",
>> },
>> + {
>> + .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
>> + .bit = QCOW2_INCOMPAT_COMPRESSION_TYPE_BITNR,
>> + .name = "compression type",
>> + },
>> };
>>
>> ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
>> @@ -3202,6 +3269,7 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
>> .refcount_table_offset = cpu_to_be64(cluster_size),
>> .refcount_table_clusters = cpu_to_be32(1),
>> .refcount_order = cpu_to_be32(refcount_order),
>> + .compression_type = cpu_to_be32(QCOW2_COMPRESSION_TYPE_ZLIB),
>> .header_length = cpu_to_be32(sizeof(*header)),
>> };
>>
>> @@ -3221,6 +3289,24 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
>> cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW);
>> }
>>
>> + if (qcow2_opts->has_compression_type &&
>> + qcow2_opts->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) {
>> +
>> + switch (qcow2_opts->compression_type) {
>> + case QCOW2_COMPRESSION_TYPE_ZLIB:
>
> a bit confusing, as it's unreachable because of if (), and because if we are here we are going to
> do a wrong thing: to set incompatible feature (so, I firstly thought that this is a bug and then
> looked above at if() condition)
Yes, there should be QCOW2_COMPRESSION_TYPE_ZSTD being added in later
patches in the series
>> + break;
>> +
>> + default:
>> + error_setg_errno(errp, -EINVAL, "Unknown compression type");
>> + goto out;
>> + }
>> +
>> + header->compression_type = cpu_to_be32(qcow2_opts->compression_type);
>> +
>> + header->incompatible_features |=
>> + cpu_to_be64(QCOW2_INCOMPAT_COMPRESSION_TYPE);
>
> cpu_to_be32 actually
true
>
>> + }
>> +
>> ret = blk_pwrite(blk, 0, header, cluster_size, 0);
>> g_free(header);
>> if (ret < 0) {
>> @@ -3402,6 +3488,7 @@ static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opt
>> { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
>> { BLOCK_OPT_COMPAT_LEVEL, "version" },
>> { BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" },
>> + { BLOCK_OPT_COMPRESSION_TYPE, "compression-type" },
>
> I think we don't need it. This array is commented as:
> /* Change legacy command line options into QMP ones */
>
> but compression-type is not a legacy option, it's a new one. Why to tolerate old notation for it?
>
>> { NULL, NULL },
>> };
>>
>> @@ -4598,6 +4685,7 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs,
>> .data_file = g_strdup(s->image_data_file),
>> .has_data_file_raw = has_data_file(bs),
>> .data_file_raw = data_file_is_raw(bs),
>> + .compression_type = s->compression_type,
>> };
>> } else {
>> /* if this assertion fails, this probably means a new version was
>> @@ -5163,6 +5251,12 @@ static QemuOptsList qcow2_create_opts = {
>> .help = "Width of a reference count entry in bits",
>> .def_value_str = "16"
>> },
>> + {
>> + .name = BLOCK_OPT_COMPRESSION_TYPE,
>> + .type = QEMU_OPT_STRING,
>> + .help = "Compression method used for image clusters compression",
>> + .def_value_str = "zlib"
>> + },
>> { /* end of list */ }
>> }
>> };
>> diff --git a/block/qcow2.h b/block/qcow2.h
>> index fc1b0d3c1e..9a241e4b9a 100644
>> --- a/block/qcow2.h
>> +++ b/block/qcow2.h
>> @@ -140,6 +140,7 @@ typedef struct QCowHeader {
>>
>> uint32_t refcount_order;
>> uint32_t header_length;
>> + uint32_t compression_type;
>> } QEMU_PACKED QCowHeader;
>>
>> typedef struct QEMU_PACKED QCowSnapshotHeader {
>> @@ -203,16 +204,20 @@ enum {
>>
>> /* Incompatible feature bits */
>> enum {
>> - QCOW2_INCOMPAT_DIRTY_BITNR = 0,
>> - QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
>> - QCOW2_INCOMPAT_DATA_FILE_BITNR = 2,
>> - 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_DIRTY_BITNR = 0,
>> + QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
>> + QCOW2_INCOMPAT_DATA_FILE_BITNR = 2,
>> + QCOW2_INCOMPAT_COMPRESSION_TYPE_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_TYPE =
>> + 1 << QCOW2_INCOMPAT_COMPRESSION_TYPE_BITNR,
>>
>> QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY
>> | QCOW2_INCOMPAT_CORRUPT
>> - | QCOW2_INCOMPAT_DATA_FILE,
>> + | QCOW2_INCOMPAT_DATA_FILE
>> + | QCOW2_INCOMPAT_COMPRESSION_TYPE,
>> };
>>
>> /* Compatible feature bits */
>> @@ -359,6 +364,13 @@ 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.
>> + * The only way to change the compression type is to convert the image
>> + * with the desired compression type set
>> + */
>> + uint32_t compression_type;
>> } BDRVQcow2State;
>>
>> typedef struct Qcow2COWRegion {
>> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
>> index af5711e533..e1be8bd5c3 100644
>> --- a/docs/interop/qcow2.txt
>> +++ b/docs/interop/qcow2.txt
>> @@ -109,7 +109,12 @@ in the description of a field.
>> An External Data File Name header extension may
>> be present if this bit is set.
>>
>> - Bits 3-63: Reserved (set to 0)
>> + Bit 3: Compression type bit. The bit must be set if
>> + the compression type differs from default of zlib.
>> + If the compression type is default the bit should
>> + be unset.
>> +
>> + Bits 4-63: Reserved (set to 0)
>>
>> 80 - 87: compatible_features
>> Bitmask of compatible features. An implementation can
>> @@ -165,6 +170,18 @@ in the description of a field.
>> Length of the header structure in bytes. For version 2
>> images, the length is always assumed to be 72 bytes.
>>
>> + 104 - 107: compression_type
>
> Why 4 bytes? 1 is enough and 2 are enough for sure. Or we need to align all fields to 4 bytes?
Each field in the header is at least 4 bytes in size including "32-35
crypt_method" which also is not expected to have a big variety of values
(now it's 3). I'm not sure but there should be some kind of reason for that.
>> + Defines the compression method used for compressed clusters.
>> + A single compression type is applied to all compressed image
>> + clusters.
>
>
>> + The compression type is set on image creation only.
>
> this sentence is not needed, why to abandon inplace conversion? And anyway, it's not
> about specification of format.
But on the other hand, it makes the intentions clearer.>
>
>
>> + The default compression type is zlib (value: 0).
>> + When the compression type differs from the default
>> + the compression type bit (incompatible feature bit 3)
>> + must be set.
>> + Available compression type values:
>> + 0: zlib <https://www.zlib.net/> (default)
>> +
>> Directly after the image header, optional sections called header extensions can
>> be stored. Each extension has a structure like the following:
>>
>> diff --git a/include/block/block_int.h b/include/block/block_int.h
>> index 3aa1e832a8..4b254802e5 100644
>> --- a/include/block/block_int.h
>> +++ b/include/block/block_int.h
>> @@ -58,6 +58,7 @@
>> #define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
>> #define BLOCK_OPT_DATA_FILE "data_file"
>> #define BLOCK_OPT_DATA_FILE_RAW "data_file_raw"
>> +#define BLOCK_OPT_COMPRESSION_TYPE "compression_type"
>>
>> #define BLOCK_PROBE_BUF_SIZE 512
>>
>> diff --git a/qapi/block-core.json b/qapi/block-core.json
>> index 0d43d4f37c..2c002ca6a9 100644
>> --- a/qapi/block-core.json
>> +++ b/qapi/block-core.json
>> @@ -78,6 +78,8 @@
>> #
>> # @bitmaps: A list of qcow2 bitmap details (since 4.0)
>> #
>> +# @compression-type: the image cluster compression method (since 4.2)
>> +#
>> # Since: 1.7
>> ##
>> { 'struct': 'ImageInfoSpecificQCow2',
>> @@ -89,7 +91,8 @@
>> '*corrupt': 'bool',
>> 'refcount-bits': 'int',
>> '*encrypt': 'ImageInfoSpecificQCow2Encryption',
>> - '*bitmaps': ['Qcow2BitmapInfo']
>> + '*bitmaps': ['Qcow2BitmapInfo'],
>> + 'compression-type': 'Qcow2CompressionType'
>> } }
>>
>> ##
>> @@ -4274,6 +4277,18 @@
>> 'data': [ 'v2', 'v3' ] }
>>
>>
>> +##
>> +# @Qcow2CompressionType:
>> +#
>> +# Compression type used in qcow2 image file
>> +#
>> +# @zlib: zlib compression, see <http://zlib.net/>
>> +#
>> +# Since: 4.2
>> +##
>> +{ 'enum': 'Qcow2CompressionType',
>> + 'data': [ 'zlib' ] }
>> +
>> ##
>> # @BlockdevCreateOptionsQcow2:
>> #
>> @@ -4297,6 +4312,8 @@
>> # allowed values: off, falloc, full, metadata)
>> # @lazy-refcounts True if refcounts may be updated lazily (default: off)
>> # @refcount-bits Width of reference counts in bits (default: 16)
>> +# @compression-type The image cluster compression method
>> +# (default: zlib, since 4.2)
>> #
>> # Since: 2.12
>> ##
>> @@ -4312,7 +4329,8 @@
>> '*cluster-size': 'size',
>> '*preallocation': 'PreallocMode',
>> '*lazy-refcounts': 'bool',
>> - '*refcount-bits': 'int' } }
>> + '*refcount-bits': 'int',
>> + '*compression-type': 'Qcow2CompressionType' } }
>>
>> ##
>> # @BlockdevCreateOptionsQed:
>>
>
>
--
Best,
Denis
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2019-08-27 14:54 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-19 15:00 [Qemu-devel] [PATCH v3 0/3] qcow2: add zstd cluster compression Denis Plotnikov
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 1/3] qcow2: introduce compression type feature Denis Plotnikov
2019-08-27 11:49 ` Vladimir Sementsov-Ogievskiy
2019-08-27 14:52 ` Denis Plotnikov
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 2/3] qcow2: rework the cluster compression routine Denis Plotnikov
2019-08-27 11:59 ` Vladimir Sementsov-Ogievskiy
2019-08-19 15:00 ` [Qemu-devel] [PATCH v3 3/3] qcow2: add zstd cluster compression Denis Plotnikov
2019-08-27 12:51 ` Vladimir Sementsov-Ogievskiy
2019-08-26 8:57 ` [Qemu-devel] [PATCH v3 0/3] " Denis Plotnikov
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