* [PATCH v11 0/4] qcow2: Implement zstd cluster compression method
@ 2020-03-30 9:54 Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 1/4] qcow2: introduce compression type feature Denis Plotnikov
` (3 more replies)
0 siblings, 4 replies; 12+ messages in thread
From: Denis Plotnikov @ 2020-03-30 9:54 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, berto, qemu-block, armbru, mreitz, den
v11:
* 03: the loops don't need "do{}while" form anymore and
the they were buggy (missed "do" in the beginning)
replace them with usual "while(){}" loops [Vladimir]
v10:
* 03: fix zstd (de)compressed loops for multi-frame
cases [Vladimir]
v9:
* 01: fix error checking and reporting in qcow2_amend compression type part [Vladimir]
* 03: replace asserts with -EIO in qcow2_zstd_decompression [Vladimir, Alberto]
* 03: reword/amend/add comments, fix typos [Vladimir]
v8:
* 03: switch zstd API from simple to stream [Eric]
No need to state a special cluster layout for zstd
compressed clusters.
v7:
* use qapi_enum_parse instead of the open-coding [Eric]
* fix wording, typos and spelling [Eric]
v6:
* "block/qcow2-threads: fix qcow2_decompress" is removed from the series
since it has been accepted by Max already
* add compile time checking for Qcow2Header to be a multiple of 8 [Max, Alberto]
* report error on qcow2 amending when the compression type is actually chnged [Max]
* remove the extra space and the extra new line [Max]
* re-arrange acks and signed-off-s [Vladimir]
v5:
* replace -ENOTSUP with abort in qcow2_co_decompress [Vladimir]
* set cluster size for all test cases in the beginning of the 287 test
v4:
* the series is rebased on top of 01 "block/qcow2-threads: fix qcow2_decompress"
* 01 is just a no-change resend to avoid extra dependencies. Still, it may be merged in separate
v3:
* remove redundant max compression type value check [Vladimir, Eric]
(the switch below checks everything)
* prevent compression type changing on "qemu-img amend" [Vladimir]
* remove zstd config setting, since it has been added already by
"migration" patches [Vladimir]
* change the compression type error message [Vladimir]
* fix alignment and 80-chars exceeding [Vladimir]
v2:
* rework compression type setting [Vladimir]
* squash iotest changes to the compression type introduction patch [Vladimir, Eric]
* fix zstd availability checking in zstd iotest [Vladimir]
* remove unnecessry casting [Eric]
* remove rudundant checks [Eric]
* fix compressed cluster layout in qcow2 spec [Vladimir]
* fix wording [Eric, Vladimir]
* fix compression type filtering in iotests [Eric]
v1:
the initial series
Denis Plotnikov (4):
qcow2: introduce compression type feature
qcow2: rework the cluster compression routine
qcow2: add zstd cluster compression
iotests: 287: add qcow2 compression type test
docs/interop/qcow2.txt | 1 +
configure | 2 +-
qapi/block-core.json | 23 +++-
block/qcow2.h | 20 ++-
include/block/block_int.h | 1 +
block/qcow2-threads.c | 209 +++++++++++++++++++++++++++++--
block/qcow2.c | 120 ++++++++++++++++++
tests/qemu-iotests/031.out | 14 +--
tests/qemu-iotests/036.out | 4 +-
tests/qemu-iotests/049.out | 102 +++++++--------
tests/qemu-iotests/060.out | 1 +
tests/qemu-iotests/061.out | 34 ++---
tests/qemu-iotests/065 | 28 +++--
tests/qemu-iotests/080 | 2 +-
tests/qemu-iotests/144.out | 4 +-
tests/qemu-iotests/182.out | 2 +-
tests/qemu-iotests/242.out | 5 +
tests/qemu-iotests/255.out | 8 +-
tests/qemu-iotests/287 | 128 +++++++++++++++++++
tests/qemu-iotests/287.out | 43 +++++++
tests/qemu-iotests/common.filter | 3 +-
tests/qemu-iotests/group | 1 +
22 files changed, 647 insertions(+), 108 deletions(-)
create mode 100755 tests/qemu-iotests/287
create mode 100644 tests/qemu-iotests/287.out
--
2.17.0
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v11 1/4] qcow2: introduce compression type feature
2020-03-30 9:54 [PATCH v11 0/4] qcow2: Implement zstd cluster compression method Denis Plotnikov
@ 2020-03-30 9:54 ` Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 2/4] qcow2: rework the cluster compression routine Denis Plotnikov
` (2 subsequent siblings)
3 siblings, 0 replies; 12+ messages in thread
From: Denis Plotnikov @ 2020-03-30 9:54 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, berto, qemu-block, armbru, mreitz, den
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, 144, 182, 242, 255
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
qapi/block-core.json | 22 +++++-
block/qcow2.h | 20 +++++-
include/block/block_int.h | 1 +
block/qcow2.c | 113 +++++++++++++++++++++++++++++++
tests/qemu-iotests/031.out | 14 ++--
tests/qemu-iotests/036.out | 4 +-
tests/qemu-iotests/049.out | 102 ++++++++++++++--------------
tests/qemu-iotests/060.out | 1 +
tests/qemu-iotests/061.out | 34 ++++++----
tests/qemu-iotests/065 | 28 +++++---
tests/qemu-iotests/080 | 2 +-
tests/qemu-iotests/144.out | 4 +-
tests/qemu-iotests/182.out | 2 +-
tests/qemu-iotests/242.out | 5 ++
tests/qemu-iotests/255.out | 8 +--
tests/qemu-iotests/common.filter | 3 +-
16 files changed, 267 insertions(+), 96 deletions(-)
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 943df1926a..d669ec0965 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 5.0)
+#
# Since: 1.7
##
{ 'struct': 'ImageInfoSpecificQCow2',
@@ -89,7 +91,8 @@
'*corrupt': 'bool',
'refcount-bits': 'int',
'*encrypt': 'ImageInfoSpecificQCow2Encryption',
- '*bitmaps': ['Qcow2BitmapInfo']
+ '*bitmaps': ['Qcow2BitmapInfo'],
+ 'compression-type': 'Qcow2CompressionType'
} }
##
@@ -4284,6 +4287,18 @@
'data': [ 'v2', 'v3' ] }
+##
+# @Qcow2CompressionType:
+#
+# Compression type used in qcow2 image file
+#
+# @zlib: zlib compression, see <http://zlib.net/>
+#
+# Since: 5.0
+##
+{ 'enum': 'Qcow2CompressionType',
+ 'data': [ 'zlib' ] }
+
##
# @BlockdevCreateOptionsQcow2:
#
@@ -4307,6 +4322,8 @@
# 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 5.0)
#
# Since: 2.12
##
@@ -4322,7 +4339,8 @@
'*cluster-size': 'size',
'*preallocation': 'PreallocMode',
'*lazy-refcounts': 'bool',
- '*refcount-bits': 'int' } }
+ '*refcount-bits': 'int',
+ '*compression-type':'Qcow2CompressionType' } }
##
# @BlockdevCreateOptionsQed:
diff --git a/block/qcow2.h b/block/qcow2.h
index 0942126232..fca2fe33f9 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 */
@@ -369,6 +380,13 @@ 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 {
diff --git a/include/block/block_int.h b/include/block/block_int.h
index ae9c4da4d0..143b2a2308 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -57,6 +57,7 @@
#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/block/qcow2.c b/block/qcow2.c
index d1da3d91db..643698934d 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1242,6 +1242,39 @@ static int qcow2_update_options(BlockDriverState *bs, QDict *options,
return ret;
}
+static int validate_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) {
+ if (s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION) {
+ error_setg(errp, "qcow2: Compression type incompatible feature "
+ "bit must not be set");
+ return -EINVAL;
+ }
+ } else {
+ if (!(s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION)) {
+ error_setg(errp, "qcow2: Compression type incompatible feature "
+ "bit must be set");
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
/* Called with s->lock held. */
static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
int flags, Error **errp)
@@ -1357,6 +1390,23 @@ 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)) {
+ s->compression_type = header.compression_type;
+ } else {
+ s->compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
+ }
+
+ ret = validate_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,
@@ -2727,6 +2777,11 @@ 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 = validate_compression_type(s, NULL);
+ if (ret) {
+ goto fail;
+ }
+
*header = (QCowHeader) {
/* Version 2 fields */
.magic = cpu_to_be32(QCOW_MAGIC),
@@ -2749,6 +2804,7 @@ 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 = s->compression_type,
};
/* For older versions, write a shorter header */
@@ -2841,6 +2897,11 @@ int qcow2_update_header(BlockDriverState *bs)
.bit = QCOW2_INCOMPAT_DATA_FILE_BITNR,
.name = "external data file",
},
+ {
+ .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
+ .bit = QCOW2_INCOMPAT_COMPRESSION_BITNR,
+ .name = "compression type",
+ },
{
.type = QCOW2_FEAT_TYPE_COMPATIBLE,
.bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
@@ -3269,6 +3330,7 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
uint64_t* refcount_table;
Error *local_err = NULL;
int ret;
+ uint8_t compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2);
qcow2_opts = &create_options->u.qcow2;
@@ -3386,6 +3448,27 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
}
}
+ if (qcow2_opts->has_compression_type &&
+ qcow2_opts->compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) {
+
+ ret = -EINVAL;
+
+ if (version < 3) {
+ error_setg(errp, "Non-zlib compression type is only supported with "
+ "compatibility level 1.1 and above (use version=v3 or "
+ "greater)");
+ goto out;
+ }
+
+ switch (qcow2_opts->compression_type) {
+ default:
+ error_setg(errp, "Unknown compression type");
+ goto out;
+ }
+
+ compression_type = qcow2_opts->compression_type;
+ }
+
/* Create BlockBackend to write to the image */
blk = blk_new(bdrv_get_aio_context(bs),
BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
@@ -3408,6 +3491,8 @@ 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),
+ /* don't deal with endianness since compression_type is 1 byte long */
+ .compression_type = compression_type,
.header_length = cpu_to_be32(sizeof(*header)),
};
@@ -3426,6 +3511,10 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
header->autoclear_features |=
cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW);
}
+ if (compression_type != QCOW2_COMPRESSION_TYPE_ZLIB) {
+ header->incompatible_features |=
+ cpu_to_be64(QCOW2_INCOMPAT_COMPRESSION);
+ }
ret = blk_pwrite(blk, 0, header, cluster_size, 0);
g_free(header);
@@ -3609,6 +3698,7 @@ 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 },
};
@@ -4831,6 +4921,7 @@ 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
@@ -5220,6 +5311,22 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
"images");
return -EINVAL;
}
+ } else if (!strcmp(desc->name, BLOCK_OPT_COMPRESSION_TYPE)) {
+ const char *ct_name =
+ qemu_opt_get(opts, BLOCK_OPT_COMPRESSION_TYPE);
+ int compression_type =
+ qapi_enum_parse(&Qcow2CompressionType_lookup, ct_name, -1,
+ NULL);
+ if (compression_type == -1) {
+ error_setg(errp, "Unknown compression type: %s", ct_name);
+ return -ENOTSUP;
+ }
+
+ if (compression_type != s->compression_type) {
+ error_setg(errp, "Changing the compression type "
+ "is not supported");
+ return -ENOTSUP;
+ }
} else {
/* if this point is reached, this probably means a new option was
* added without having it covered here */
@@ -5488,6 +5595,12 @@ 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 cluster compression",
+ .def_value_str = "zlib"
+ },
{ /* end of list */ }
}
};
diff --git a/tests/qemu-iotests/031.out b/tests/qemu-iotests/031.out
index d535e407bc..ed51afe9ce 100644
--- a/tests/qemu-iotests/031.out
+++ b/tests/qemu-iotests/031.out
@@ -113,11 +113,11 @@ incompatible_features []
compatible_features []
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
Header extension:
@@ -146,11 +146,11 @@ incompatible_features []
compatible_features []
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
Header extension:
@@ -164,7 +164,7 @@ No errors were found on the image.
magic 0x514649fb
version 3
-backing_file_offset 0x178
+backing_file_offset 0x1b0
backing_file_size 0x17
cluster_bits 16
size 67108864
@@ -179,7 +179,7 @@ incompatible_features []
compatible_features []
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0xe2792aca
@@ -188,7 +188,7 @@ data 'host_device'
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
Header extension:
diff --git a/tests/qemu-iotests/036.out b/tests/qemu-iotests/036.out
index 0b52b934e1..fb509f6357 100644
--- a/tests/qemu-iotests/036.out
+++ b/tests/qemu-iotests/036.out
@@ -26,7 +26,7 @@ compatible_features []
autoclear_features [63]
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
@@ -38,7 +38,7 @@ compatible_features []
autoclear_features []
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
*** done
diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
index affa55b341..a5cfba1756 100644
--- a/tests/qemu-iotests/049.out
+++ b/tests/qemu-iotests/049.out
@@ -4,90 +4,90 @@ QA output created by 049
== 1. Traditional size parameter ==
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024b
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1k
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1K
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1T
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024.0
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024.0b
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5k
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5K
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5T
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
== 2. Specifying size via -o ==
qemu-img create -f qcow2 -o size=1024 TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1024b TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1k TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1K TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1M TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1G TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1T TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1024.0 TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1024.0b TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1.5k TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1.5K TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1.5M TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1.5G TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o size=1.5T TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
== 3. Invalid sizes ==
@@ -129,84 +129,84 @@ qemu-img: TEST_DIR/t.qcow2: The image size must be specified only once
== Check correct interpretation of suffixes for cluster size ==
qemu-img create -f qcow2 -o cluster_size=1024 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=1024b TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=1k TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=1K TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=1M TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1048576 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1048576 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=1024.0 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=1024.0b TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=1024 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=0.5k TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=512 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=512 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=0.5K TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=512 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=512 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o cluster_size=0.5M TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=524288 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=524288 lazy_refcounts=off refcount_bits=16 compression_type=zlib
== Check compat level option ==
qemu-img create -f qcow2 -o compat=0.10 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.10 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.10 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o compat=1.1 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=1.1 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=1.1 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o compat=0.42 TEST_DIR/t.qcow2 64M
qemu-img: TEST_DIR/t.qcow2: Invalid parameter '0.42'
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.42 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.42 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o compat=foobar TEST_DIR/t.qcow2 64M
qemu-img: TEST_DIR/t.qcow2: Invalid parameter 'foobar'
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=foobar cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=foobar cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
== Check preallocation option ==
qemu-img create -f qcow2 -o preallocation=off TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=65536 preallocation=off lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=65536 preallocation=off lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o preallocation=metadata TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=65536 preallocation=metadata lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=65536 preallocation=metadata lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o preallocation=1234 TEST_DIR/t.qcow2 64M
qemu-img: TEST_DIR/t.qcow2: Invalid parameter '1234'
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=65536 preallocation=1234 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=65536 preallocation=1234 lazy_refcounts=off refcount_bits=16 compression_type=zlib
== Check encryption option ==
qemu-img create -f qcow2 -o encryption=off TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 --object secret,id=sec0,data=123456 -o encryption=on,encrypt.key-secret=sec0 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=on encrypt.key-secret=sec0 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=on encrypt.key-secret=sec0 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
== Check lazy_refcounts option (only with v3) ==
qemu-img create -f qcow2 -o compat=1.1,lazy_refcounts=off TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=1.1 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=1.1 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o compat=1.1,lazy_refcounts=on TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=1.1 cluster_size=65536 lazy_refcounts=on refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=1.1 cluster_size=65536 lazy_refcounts=on refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=off TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.10 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.10 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=on TEST_DIR/t.qcow2 64M
qemu-img: TEST_DIR/t.qcow2: Lazy refcounts only supported with compatibility level 1.1 and above (use version=v3 or greater)
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.10 cluster_size=65536 lazy_refcounts=on refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.10 cluster_size=65536 lazy_refcounts=on refcount_bits=16 compression_type=zlib
*** done
diff --git a/tests/qemu-iotests/060.out b/tests/qemu-iotests/060.out
index d27692a33c..3e47f537e8 100644
--- a/tests/qemu-iotests/060.out
+++ b/tests/qemu-iotests/060.out
@@ -17,6 +17,7 @@ virtual size: 64 MiB (67108864 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
refcount bits: 16
corrupt: true
diff --git a/tests/qemu-iotests/061.out b/tests/qemu-iotests/061.out
index 8b3091a412..c913f02ad6 100644
--- a/tests/qemu-iotests/061.out
+++ b/tests/qemu-iotests/061.out
@@ -22,11 +22,11 @@ incompatible_features []
compatible_features [0]
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
magic 0x514649fb
@@ -80,11 +80,11 @@ incompatible_features []
compatible_features [0]
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
magic 0x514649fb
@@ -136,11 +136,11 @@ incompatible_features [0]
compatible_features [0]
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
ERROR cluster 5 refcount=0 reference=1
@@ -191,11 +191,11 @@ incompatible_features []
compatible_features [42]
autoclear_features [42]
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
magic 0x514649fb
@@ -260,11 +260,11 @@ incompatible_features []
compatible_features [0]
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
read 65536/65536 bytes at offset 44040192
@@ -294,11 +294,11 @@ incompatible_features [0]
compatible_features [0]
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
ERROR cluster 5 refcount=0 reference=1
@@ -323,11 +323,11 @@ incompatible_features []
compatible_features []
autoclear_features []
refcount_order 4
-header_length 104
+header_length 112
Header extension:
magic 0x6803f857
-length 192
+length 240
data <binary>
read 131072/131072 bytes at offset 0
@@ -491,6 +491,7 @@ virtual size: 64 MiB (67108864 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
refcount bits: 16
data file: TEST_DIR/t.IMGFMT.data
@@ -511,6 +512,7 @@ virtual size: 64 MiB (67108864 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
refcount bits: 16
data file: foo
@@ -524,6 +526,7 @@ virtual size: 64 MiB (67108864 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
refcount bits: 16
data file raw: false
@@ -538,6 +541,7 @@ virtual size: 64 MiB (67108864 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
refcount bits: 16
data file: TEST_DIR/t.IMGFMT.data
@@ -550,6 +554,7 @@ virtual size: 64 MiB (67108864 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
refcount bits: 16
data file: TEST_DIR/t.IMGFMT.data
@@ -563,6 +568,7 @@ virtual size: 64 MiB (67108864 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
refcount bits: 16
data file: TEST_DIR/t.IMGFMT.data
diff --git a/tests/qemu-iotests/065 b/tests/qemu-iotests/065
index 6426474271..18dc488c7a 100755
--- a/tests/qemu-iotests/065
+++ b/tests/qemu-iotests/065
@@ -88,24 +88,30 @@ class TestQMP(TestImageInfoSpecific):
class TestQCow2(TestQemuImgInfo):
'''Testing a qcow2 version 2 image'''
img_options = 'compat=0.10'
- json_compare = { 'compat': '0.10', 'refcount-bits': 16 }
- human_compare = [ 'compat: 0.10', 'refcount bits: 16' ]
+ json_compare = { 'compat': '0.10', 'refcount-bits': 16,
+ 'compression-type': 'zlib' }
+ human_compare = [ 'compat: 0.10', 'compression type: zlib',
+ 'refcount bits: 16' ]
class TestQCow3NotLazy(TestQemuImgInfo):
'''Testing a qcow2 version 3 image with lazy refcounts disabled'''
img_options = 'compat=1.1,lazy_refcounts=off'
json_compare = { 'compat': '1.1', 'lazy-refcounts': False,
- 'refcount-bits': 16, 'corrupt': False }
- human_compare = [ 'compat: 1.1', 'lazy refcounts: false',
- 'refcount bits: 16', 'corrupt: false' ]
+ 'refcount-bits': 16, 'corrupt': False,
+ 'compression-type': 'zlib' }
+ human_compare = [ 'compat: 1.1', 'compression type: zlib',
+ 'lazy refcounts: false', 'refcount bits: 16',
+ 'corrupt: false' ]
class TestQCow3Lazy(TestQemuImgInfo):
'''Testing a qcow2 version 3 image with lazy refcounts enabled'''
img_options = 'compat=1.1,lazy_refcounts=on'
json_compare = { 'compat': '1.1', 'lazy-refcounts': True,
- 'refcount-bits': 16, 'corrupt': False }
- human_compare = [ 'compat: 1.1', 'lazy refcounts: true',
- 'refcount bits: 16', 'corrupt: false' ]
+ 'refcount-bits': 16, 'corrupt': False,
+ 'compression-type': 'zlib' }
+ human_compare = [ 'compat: 1.1', 'compression type: zlib',
+ 'lazy refcounts: true', 'refcount bits: 16',
+ 'corrupt: false' ]
class TestQCow3NotLazyQMP(TestQMP):
'''Testing a qcow2 version 3 image with lazy refcounts disabled, opening
@@ -113,7 +119,8 @@ class TestQCow3NotLazyQMP(TestQMP):
img_options = 'compat=1.1,lazy_refcounts=off'
qemu_options = 'lazy-refcounts=on'
compare = { 'compat': '1.1', 'lazy-refcounts': False,
- 'refcount-bits': 16, 'corrupt': False }
+ 'refcount-bits': 16, 'corrupt': False,
+ 'compression-type': 'zlib' }
class TestQCow3LazyQMP(TestQMP):
@@ -122,7 +129,8 @@ class TestQCow3LazyQMP(TestQMP):
img_options = 'compat=1.1,lazy_refcounts=on'
qemu_options = 'lazy-refcounts=off'
compare = { 'compat': '1.1', 'lazy-refcounts': True,
- 'refcount-bits': 16, 'corrupt': False }
+ 'refcount-bits': 16, 'corrupt': False,
+ 'compression-type': 'zlib' }
TestImageInfoSpecific = None
TestQemuImgInfo = None
diff --git a/tests/qemu-iotests/080 b/tests/qemu-iotests/080
index a3d13c414e..7588c63b6c 100755
--- a/tests/qemu-iotests/080
+++ b/tests/qemu-iotests/080
@@ -45,7 +45,7 @@ _supported_os Linux
# - This is generally a test for compat=1.1 images
_unsupported_imgopts 'refcount_bits=1[^0-9]' data_file 'compat=0.10'
-header_size=104
+header_size=112
offset_backing_file_offset=8
offset_backing_file_size=16
diff --git a/tests/qemu-iotests/144.out b/tests/qemu-iotests/144.out
index c7aa2e4820..885a8874a5 100644
--- a/tests/qemu-iotests/144.out
+++ b/tests/qemu-iotests/144.out
@@ -9,7 +9,7 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=536870912
{ 'execute': 'qmp_capabilities' }
{"return": {}}
{ 'execute': 'blockdev-snapshot-sync', 'arguments': { 'device': 'virtio0', 'snapshot-file':'TEST_DIR/tmp.IMGFMT', 'format': 'IMGFMT' } }
-Formatting 'TEST_DIR/tmp.qcow2', fmt=qcow2 size=536870912 backing_file=TEST_DIR/t.qcow2 backing_fmt=qcow2 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/tmp.qcow2', fmt=qcow2 size=536870912 backing_file=TEST_DIR/t.qcow2 backing_fmt=qcow2 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
{"return": {}}
=== Performing block-commit on active layer ===
@@ -31,6 +31,6 @@ Formatting 'TEST_DIR/tmp.qcow2', fmt=qcow2 size=536870912 backing_file=TEST_DIR/
=== Performing Live Snapshot 2 ===
{ 'execute': 'blockdev-snapshot-sync', 'arguments': { 'device': 'virtio0', 'snapshot-file':'TEST_DIR/tmp2.IMGFMT', 'format': 'IMGFMT' } }
-Formatting 'TEST_DIR/tmp2.qcow2', fmt=qcow2 size=536870912 backing_file=TEST_DIR/t.qcow2 backing_fmt=qcow2 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/tmp2.qcow2', fmt=qcow2 size=536870912 backing_file=TEST_DIR/t.qcow2 backing_fmt=qcow2 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
{"return": {}}
*** done
diff --git a/tests/qemu-iotests/182.out b/tests/qemu-iotests/182.out
index a8eea166c3..ae43654d32 100644
--- a/tests/qemu-iotests/182.out
+++ b/tests/qemu-iotests/182.out
@@ -13,7 +13,7 @@ Is another process using the image [TEST_DIR/t.qcow2]?
{'execute': 'blockdev-add', 'arguments': { 'node-name': 'node0', 'driver': 'file', 'filename': 'TEST_DIR/t.IMGFMT', 'locking': 'on' } }
{"return": {}}
{'execute': 'blockdev-snapshot-sync', 'arguments': { 'node-name': 'node0', 'snapshot-file': 'TEST_DIR/t.IMGFMT.overlay', 'snapshot-node-name': 'node1' } }
-Formatting 'TEST_DIR/t.qcow2.overlay', fmt=qcow2 size=197120 backing_file=TEST_DIR/t.qcow2 backing_fmt=file cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/t.qcow2.overlay', fmt=qcow2 size=197120 backing_file=TEST_DIR/t.qcow2 backing_fmt=file cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
{"return": {}}
{'execute': 'blockdev-add', 'arguments': { 'node-name': 'node1', 'driver': 'file', 'filename': 'TEST_DIR/t.IMGFMT', 'locking': 'on' } }
{"return": {}}
diff --git a/tests/qemu-iotests/242.out b/tests/qemu-iotests/242.out
index 7ac8404d11..091b9126ce 100644
--- a/tests/qemu-iotests/242.out
+++ b/tests/qemu-iotests/242.out
@@ -12,6 +12,7 @@ virtual size: 1 MiB (1048576 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
refcount bits: 16
corrupt: false
@@ -32,6 +33,7 @@ virtual size: 1 MiB (1048576 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
bitmaps:
[0]:
@@ -64,6 +66,7 @@ virtual size: 1 MiB (1048576 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
bitmaps:
[0]:
@@ -104,6 +107,7 @@ virtual size: 1 MiB (1048576 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
bitmaps:
[0]:
@@ -153,6 +157,7 @@ virtual size: 1 MiB (1048576 bytes)
cluster_size: 65536
Format specific information:
compat: 1.1
+ compression type: zlib
lazy refcounts: false
bitmaps:
[0]:
diff --git a/tests/qemu-iotests/255.out b/tests/qemu-iotests/255.out
index 348909fdef..a3c99fd62e 100644
--- a/tests/qemu-iotests/255.out
+++ b/tests/qemu-iotests/255.out
@@ -3,9 +3,9 @@ Finishing a commit job with background reads
=== Create backing chain and start VM ===
-Formatting 'TEST_DIR/PID-t.qcow2.mid', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/PID-t.qcow2.mid', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
-Formatting 'TEST_DIR/PID-t.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/PID-t.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
=== Start background read requests ===
@@ -23,9 +23,9 @@ Closing the VM while a job is being cancelled
=== Create images and start VM ===
-Formatting 'TEST_DIR/PID-src.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/PID-src.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
-Formatting 'TEST_DIR/PID-dst.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16
+Formatting 'TEST_DIR/PID-dst.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib
wrote 1048576/1048576 bytes at offset 0
1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
diff --git a/tests/qemu-iotests/common.filter b/tests/qemu-iotests/common.filter
index 3f8ee3e5f7..279e0bbb0d 100644
--- a/tests/qemu-iotests/common.filter
+++ b/tests/qemu-iotests/common.filter
@@ -152,7 +152,8 @@ _filter_img_create()
-e "s# refcount_bits=[0-9]\\+##g" \
-e "s# key-secret=[a-zA-Z0-9]\\+##g" \
-e "s# iter-time=[0-9]\\+##g" \
- -e "s# force_size=\\(on\\|off\\)##g"
+ -e "s# force_size=\\(on\\|off\\)##g" \
+ -e "s# compression_type=[a-zA-Z0-9]\\+##g"
}
_filter_img_info()
--
2.17.0
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v11 2/4] qcow2: rework the cluster compression routine
2020-03-30 9:54 [PATCH v11 0/4] qcow2: Implement zstd cluster compression method Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 1/4] qcow2: introduce compression type feature Denis Plotnikov
@ 2020-03-30 9:54 ` Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 3/4] qcow2: add zstd cluster compression Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 4/4] iotests: 287: add qcow2 compression type test Denis Plotnikov
3 siblings, 0 replies; 12+ messages in thread
From: Denis Plotnikov @ 2020-03-30 9:54 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, berto, qemu-block, armbru, mreitz, den
The patch enables processing the image compression type defined
for the image and chooses an appropriate method for image clusters
(de)compression.
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
---
block/qcow2-threads.c | 71 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 60 insertions(+), 11 deletions(-)
diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
index a68126f291..7dbaf53489 100644
--- a/block/qcow2-threads.c
+++ b/block/qcow2-threads.c
@@ -74,7 +74,9 @@ typedef struct Qcow2CompressData {
} 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 +85,8 @@ 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;
@@ -119,10 +121,10 @@ 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
@@ -130,8 +132,8 @@ static ssize_t qcow2_compress(void *dest, size_t dest_size,
* Returns: 0 on success
* -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;
z_stream strm;
@@ -191,20 +193,67 @@ 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: compressed size on success
+ * a negative error code on failure
+ */
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:
+ abort();
+ }
+
+ 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 failure
+ */
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:
+ abort();
+ }
+
+ return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
}
--
2.17.0
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v11 3/4] qcow2: add zstd cluster compression
2020-03-30 9:54 [PATCH v11 0/4] qcow2: Implement zstd cluster compression method Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 1/4] qcow2: introduce compression type feature Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 2/4] qcow2: rework the cluster compression routine Denis Plotnikov
@ 2020-03-30 9:54 ` Denis Plotnikov
2020-03-30 13:14 ` Vladimir Sementsov-Ogievskiy
2020-03-30 9:54 ` [PATCH v11 4/4] iotests: 287: add qcow2 compression type test Denis Plotnikov
3 siblings, 1 reply; 12+ messages in thread
From: Denis Plotnikov @ 2020-03-30 9:54 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, berto, qemu-block, armbru, mreitz, den
zstd significantly reduces cluster compression time.
It provides better compression performance maintaining
the same level of the compression ratio in comparison with
zlib, which, at the moment, is 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>
QAPI part:
Acked-by: Markus Armbruster <armbru@redhat.com>
---
docs/interop/qcow2.txt | 1 +
configure | 2 +-
qapi/block-core.json | 3 +-
block/qcow2-threads.c | 138 +++++++++++++++++++++++++++++++++++++++++
block/qcow2.c | 7 +++
5 files changed, 149 insertions(+), 2 deletions(-)
diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
index 5597e24474..795dbb21dd 100644
--- a/docs/interop/qcow2.txt
+++ b/docs/interop/qcow2.txt
@@ -208,6 +208,7 @@ version 2.
Available compression type values:
0: zlib <https://www.zlib.net/>
+ 1: zstd <http://github.com/facebook/zstd>
=== Header padding ===
diff --git a/configure b/configure
index da09c35895..57cac2abe1 100755
--- a/configure
+++ b/configure
@@ -1861,7 +1861,7 @@ disabled with --disable-FEATURE, default is enabled if available:
lzfse support of lzfse compression library
(for reading lzfse-compressed dmg images)
zstd support for zstd compression library
- (for migration compression)
+ (for migration compression and qcow2 cluster compression)
seccomp seccomp support
coroutine-pool coroutine freelist (better performance)
glusterfs GlusterFS backend
diff --git a/qapi/block-core.json b/qapi/block-core.json
index d669ec0965..44690ed266 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -4293,11 +4293,12 @@
# Compression type used in qcow2 image file
#
# @zlib: zlib compression, see <http://zlib.net/>
+# @zstd: zstd compression, see <http://github.com/facebook/zstd>
#
# Since: 5.0
##
{ 'enum': 'Qcow2CompressionType',
- 'data': [ 'zlib' ] }
+ 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] }
##
# @BlockdevCreateOptionsQcow2:
diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
index 7dbaf53489..b8ccd97009 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"
@@ -166,6 +171,129 @@ 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)
+{
+ size_t ret;
+ ZSTD_outBuffer output = { dest, dest_size, 0 };
+ ZSTD_inBuffer input = { src, src_size, 0 };
+ ZSTD_CCtx *cctx = ZSTD_createCCtx();
+
+ if (!cctx) {
+ return -EIO;
+ }
+ /*
+ * ZSTD spec: "You must continue calling ZSTD_compressStream2()
+ * with ZSTD_e_end until it returns 0, at which point you are
+ * free to start a new frame".
+ * In the loop, we try to compress all the data into one zstd frame.
+ * ZSTD_compressStream2 can potentially finish a frame earlier
+ * than the full input data is consumed. That's why we are looping
+ * until all the input data is consumed.
+ */
+ while (input.pos < input.size) {
+ /*
+ * zstd simple interface requires the exact compressed size.
+ * zstd stream interface reads the comressed size from
+ * the compressed stream frame.
+ * Instruct zstd to compress the whole buffer and write
+ * the frame which includes the compressed size.
+ * This allows as to use zstd streaming semantics and
+ * don't store the compressed size for the zstd decompression.
+ */
+ ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);
+ if (ZSTD_isError(ret)) {
+ ret = -EIO;
+ goto out;
+ }
+ /* Dest buffer isn't big enough to store compressed content */
+ if (output.pos + ret > output.size) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ };
+
+ /* make sure we can safely return compressed buffer size with ssize_t */
+ assert(output.pos <= SSIZE_MAX);
+ ret = output.pos;
+
+out:
+ ZSTD_freeCCtx(cctx);
+ return ret;
+}
+
+/*
+ * 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)
+{
+ size_t ret = 0;
+ ZSTD_outBuffer output = { dest, dest_size, 0 };
+ ZSTD_inBuffer input = { src, src_size, 0 };
+ ZSTD_DCtx *dctx = ZSTD_createDCtx();
+
+ if (!dctx) {
+ return -EIO;
+ }
+
+ /*
+ * The compressed stream from input buffer may consist from more
+ * than one zstd frames. So we iterate until we get a fully
+ * uncompressed cluster.
+ */
+ while (output.pos < output.size) {
+ ret = ZSTD_decompressStream(dctx, &output, &input);
+ /*
+ * if we don't fully populate the output but have read
+ * all the frames from the input, we end up with error
+ * here
+ */
+ if (ZSTD_isError(ret)) {
+ ret = -EIO;
+ break;
+ }
+ /*
+ * Dest buffer size is the image cluster size.
+ * It should be big enough to store uncompressed content.
+ * There shouldn't be any cases when the decompressed content
+ * size is greater then the cluster size, except cluster
+ * damaging.
+ */
+ if (output.pos + ret > output.size) {
+ ret = -EIO;
+ break;
+ }
+ }
+
+ ZSTD_freeDCtx(dctx);
+ return ret;
+}
+#endif
+
static int qcow2_compress_pool_func(void *opaque)
{
Qcow2CompressData *data = opaque;
@@ -217,6 +345,11 @@ 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:
abort();
}
@@ -249,6 +382,11 @@ 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:
abort();
}
diff --git a/block/qcow2.c b/block/qcow2.c
index 643698934d..6632daf50b 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1246,6 +1246,9 @@ static int validate_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:
@@ -3461,6 +3464,10 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
}
switch (qcow2_opts->compression_type) {
+#ifdef CONFIG_ZSTD
+ case QCOW2_COMPRESSION_TYPE_ZSTD:
+ break;
+#endif
default:
error_setg(errp, "Unknown compression type");
goto out;
--
2.17.0
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v11 4/4] iotests: 287: add qcow2 compression type test
2020-03-30 9:54 [PATCH v11 0/4] qcow2: Implement zstd cluster compression method Denis Plotnikov
` (2 preceding siblings ...)
2020-03-30 9:54 ` [PATCH v11 3/4] qcow2: add zstd cluster compression Denis Plotnikov
@ 2020-03-30 9:54 ` Denis Plotnikov
3 siblings, 0 replies; 12+ messages in thread
From: Denis Plotnikov @ 2020-03-30 9:54 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, vsementsov, berto, qemu-block, armbru, mreitz, den
The test checks fulfilling qcow2 requiriements for the compression
type feature and zstd compression type operability.
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
tests/qemu-iotests/287 | 128 +++++++++++++++++++++++++++++++++++++
tests/qemu-iotests/287.out | 43 +++++++++++++
tests/qemu-iotests/group | 1 +
3 files changed, 172 insertions(+)
create mode 100755 tests/qemu-iotests/287
create mode 100644 tests/qemu-iotests/287.out
diff --git a/tests/qemu-iotests/287 b/tests/qemu-iotests/287
new file mode 100755
index 0000000000..49d15b3d43
--- /dev/null
+++ b/tests/qemu-iotests/287
@@ -0,0 +1,128 @@
+#!/usr/bin/env bash
+#
+# Test case for an image using zstd compression
+#
+# Copyright (c) 2020 Virtuozzo International GmbH
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=dplotnikov@virtuozzo.com
+
+seq="$(basename $0)"
+echo "QA output created by $seq"
+
+status=1 # failure is the default!
+
+_cleanup()
+{
+ _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# standard environment
+. ./common.rc
+. ./common.filter
+
+# This tests qocw2-specific low-level functionality
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+# for all the cases
+CLUSTER_SIZE=65536
+
+# Check if we can run this test.
+
+IMGOPTS='compression_type=zstd' _make_test_img 64M | grep "Invalid parameter 'zstd'" 2>&1 1>/dev/null
+
+ZSTD_SUPPORTED=$?
+
+if (($ZSTD_SUPPORTED==0)); then
+ _notrun "ZSTD is disabled"
+fi
+
+# Test: when compression is zlib the incompatible bit is unset
+echo
+echo "=== Testing compression type incompatible bit setting for zlib ==="
+echo
+
+IMGOPTS='compression_type=zlib' _make_test_img 64M
+$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
+
+# Test: when compression differs from zlib the incompatible bit is set
+echo
+echo "=== Testing compression type incompatible bit setting for zstd ==="
+echo
+
+IMGOPTS='compression_type=zstd' _make_test_img 64M
+$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
+
+# Test: an image can't be openned if compression type is zlib and
+# incompatible feature compression type is set
+echo
+echo "=== Testing zlib with incompatible bit set ==="
+echo
+
+IMGOPTS='compression_type=zlib' _make_test_img 64M
+$PYTHON qcow2.py "$TEST_IMG" set-feature-bit incompatible 3
+# to make sure the bit was actually set
+$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
+$QEMU_IMG info "$TEST_IMG" 2>1 1>/dev/null
+if (($?==0)); then
+ echo "Error: The image openned successfully. The image must not be openned"
+fi
+
+# Test: an image can't be openned if compression type is NOT zlib and
+# incompatible feature compression type is UNSET
+echo
+echo "=== Testing zstd with incompatible bit unset ==="
+echo
+
+IMGOPTS='compression_type=zstd' _make_test_img 64M
+$PYTHON qcow2.py "$TEST_IMG" set-header incompatible_features 0
+# to make sure the bit was actually unset
+$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
+$QEMU_IMG info "$TEST_IMG" 2>1 1>/dev/null
+if (($?==0)); then
+ echo "Error: The image openned successfully. The image must not be openned"
+fi
+# Test: check compression type values
+echo
+echo "=== Testing compression type values ==="
+echo
+# zlib=0
+IMGOPTS='compression_type=zlib' _make_test_img 64M
+od -j104 -N1 -An -vtu1 "$TEST_IMG"
+
+# zstd=1
+IMGOPTS='compression_type=zstd' _make_test_img 64M
+od -j104 -N1 -An -vtu1 "$TEST_IMG"
+
+# Test: using zstd compression, write to and read from an image
+echo
+echo "=== Testing reading and writing with zstd ==="
+echo
+
+IMGOPTS='compression_type=zstd' _make_test_img 64M
+$QEMU_IO -c "write -c -P 0xAC 65536 64k " "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c "read -P 0xAC 65536 65536 " "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c "read -v 131070 8 " "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c "read -v 65534 8" "$TEST_IMG" | _filter_qemu_io
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/287.out b/tests/qemu-iotests/287.out
new file mode 100644
index 0000000000..8e51c3078d
--- /dev/null
+++ b/tests/qemu-iotests/287.out
@@ -0,0 +1,43 @@
+QA output created by 287
+
+=== Testing compression type incompatible bit setting for zlib ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+incompatible_features []
+
+=== Testing compression type incompatible bit setting for zstd ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+incompatible_features [3]
+
+=== Testing zlib with incompatible bit set ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+incompatible_features [3]
+
+=== Testing zstd with incompatible bit unset ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+incompatible_features []
+
+=== Testing compression type values ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+ 0
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+ 1
+
+=== Testing reading and writing with zstd ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+wrote 65536/65536 bytes at offset 65536
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 65536/65536 bytes at offset 65536
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+0001fffe: ac ac 00 00 00 00 00 00 ........
+read 8/8 bytes at offset 131070
+8 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+0000fffe: 00 00 ac ac ac ac ac ac ........
+read 8/8 bytes at offset 65534
+8 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 79c6dfc85d..dacbcfc12d 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -294,5 +294,6 @@
283 auto quick
284 rw
286 rw quick
+287 auto quick
288 quick
289 rw quick
--
2.17.0
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH v11 3/4] qcow2: add zstd cluster compression
2020-03-30 9:54 ` [PATCH v11 3/4] qcow2: add zstd cluster compression Denis Plotnikov
@ 2020-03-30 13:14 ` Vladimir Sementsov-Ogievskiy
2020-03-30 15:04 ` Denis Plotnikov
0 siblings, 1 reply; 12+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-03-30 13:14 UTC (permalink / raw)
To: Denis Plotnikov, qemu-devel; +Cc: kwolf, berto, qemu-block, armbru, mreitz, den
30.03.2020 12:54, Denis Plotnikov wrote:
> zstd significantly reduces cluster compression time.
> It provides better compression performance maintaining
> the same level of the compression ratio in comparison with
> zlib, which, at the moment, is 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>
> QAPI part:
> Acked-by: Markus Armbruster <armbru@redhat.com>
> ---
> docs/interop/qcow2.txt | 1 +
> configure | 2 +-
> qapi/block-core.json | 3 +-
> block/qcow2-threads.c | 138 +++++++++++++++++++++++++++++++++++++++++
> block/qcow2.c | 7 +++
> 5 files changed, 149 insertions(+), 2 deletions(-)
>
> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
> index 5597e24474..795dbb21dd 100644
> --- a/docs/interop/qcow2.txt
> +++ b/docs/interop/qcow2.txt
> @@ -208,6 +208,7 @@ version 2.
>
> Available compression type values:
> 0: zlib <https://www.zlib.net/>
> + 1: zstd <http://github.com/facebook/zstd>
>
>
> === Header padding ===
> diff --git a/configure b/configure
> index da09c35895..57cac2abe1 100755
> --- a/configure
> +++ b/configure
> @@ -1861,7 +1861,7 @@ disabled with --disable-FEATURE, default is enabled if available:
> lzfse support of lzfse compression library
> (for reading lzfse-compressed dmg images)
> zstd support for zstd compression library
> - (for migration compression)
> + (for migration compression and qcow2 cluster compression)
> seccomp seccomp support
> coroutine-pool coroutine freelist (better performance)
> glusterfs GlusterFS backend
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index d669ec0965..44690ed266 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -4293,11 +4293,12 @@
> # Compression type used in qcow2 image file
> #
> # @zlib: zlib compression, see <http://zlib.net/>
> +# @zstd: zstd compression, see <http://github.com/facebook/zstd>
> #
> # Since: 5.0
> ##
> { 'enum': 'Qcow2CompressionType',
> - 'data': [ 'zlib' ] }
> + 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] }
>
> ##
> # @BlockdevCreateOptionsQcow2:
> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
> index 7dbaf53489..b8ccd97009 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"
> @@ -166,6 +171,129 @@ 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)
> +{
> + size_t ret;
> + ZSTD_outBuffer output = { dest, dest_size, 0 };
> + ZSTD_inBuffer input = { src, src_size, 0 };
> + ZSTD_CCtx *cctx = ZSTD_createCCtx();
> +
> + if (!cctx) {
> + return -EIO;
> + }
> + /*
> + * ZSTD spec: "You must continue calling ZSTD_compressStream2()
> + * with ZSTD_e_end until it returns 0, at which point you are
> + * free to start a new frame".
> + * In the loop, we try to compress all the data into one zstd frame.
> + * ZSTD_compressStream2 can potentially finish a frame earlier
> + * than the full input data is consumed. That's why we are looping
> + * until all the input data is consumed.
> + */
> + while (input.pos < input.size) {
> + /*
> + * zstd simple interface requires the exact compressed size.
on decompression you mean
> + * zstd stream interface reads the comressed size from
> + * the compressed stream frame.
compressed size is not stored in the stream. I think, that streamed
interface just decompress until it have something to decompress and
have space to write output.
> + * Instruct zstd to compress the whole buffer and write
> + * the frame which includes the compressed size.
I think this is wrong. compression size is not written.
> + * This allows as to use zstd streaming semantics and
> + * don't store the compressed size for the zstd decompression.
> + */
Comment is just outdated. Accordingly to our off-list discussion, I'd
rewrite it like this:
We want to use streamed interface on decompression, as we will not know
exact size of compression data. Use streamed interface for compression
just for symmetry.
> + ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);
> + if (ZSTD_isError(ret)) {
> + ret = -EIO;
> + goto out;
> + }
> + /* Dest buffer isn't big enough to store compressed content */
> + if (output.pos + ret > output.size) {
> + ret = -ENOMEM;
> + goto out;
> + }
Here you use "@return provides a minimum amount of data remaining to be flushed from internal buffers
or an error code, which can be tested using ZSTD_isError()."
I think we can safely drop this check, and wait for error from next ZSTD_compressStream2.. But it should
work anyway.
> + };
> +
> + /* make sure we can safely return compressed buffer size with ssize_t */
> + assert(output.pos <= SSIZE_MAX);
Hmm. I hope it's not possible for cluster. But taking the function in separate, it _is_ possible.
So may be better to assert at function start that
assert(dest_size <= SSIZE_MAX);
To stress, that this limitation is part of qcow2_zstd_compress() interface.
> + ret = output.pos;
> +
> +out:
> + ZSTD_freeCCtx(cctx);
> + return ret;
> +}
> +
> +/*
> + * 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)
> +{
> + size_t ret = 0;
> + ZSTD_outBuffer output = { dest, dest_size, 0 };
> + ZSTD_inBuffer input = { src, src_size, 0 };
> + ZSTD_DCtx *dctx = ZSTD_createDCtx();
> +
> + if (!dctx) {
> + return -EIO;
> + }
> +
> + /*
> + * The compressed stream from input buffer may consist from more
> + * than one zstd frames. So we iterate until we get a fully
> + * uncompressed cluster.
> + */
> + while (output.pos < output.size) {
> + ret = ZSTD_decompressStream(dctx, &output, &input);
> + /*
> + * if we don't fully populate the output but have read
> + * all the frames from the input, we end up with error
> + * here
> + */
> + if (ZSTD_isError(ret)) {
> + ret = -EIO;
> + break;
> + }
> + /*
> + * Dest buffer size is the image cluster size.
> + * It should be big enough to store uncompressed content.
> + * There shouldn't be any cases when the decompressed content
> + * size is greater then the cluster size, except cluster
> + * damaging.
> + */
> + if (output.pos + ret > output.size) {
> + ret = -EIO;
> + break;
> + }
But here, you use
"
or any other value > 0, which means there is still some decoding or flushing to do to complete current frame :
the return value is a suggested next input size (just a hint for better latency)
that will never request more than the remaining frame size.
"
I'm afraid that "just a hint" is not safe API to make a conclusion from. So, I'd prefer to drop this optimization
and just wait for an error from next ZSTD_decompressStream.
And therefore, for symmetry drop similar optimization on compression part..
What do you think?
> + }
> +
> + ZSTD_freeDCtx(dctx);
> + return ret;
> +}
> +#endif
> +
> static int qcow2_compress_pool_func(void *opaque)
> {
> Qcow2CompressData *data = opaque;
> @@ -217,6 +345,11 @@ 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:
> abort();
> }
> @@ -249,6 +382,11 @@ 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:
> abort();
> }
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 643698934d..6632daf50b 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1246,6 +1246,9 @@ static int validate_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:
> @@ -3461,6 +3464,10 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
> }
>
> switch (qcow2_opts->compression_type) {
> +#ifdef CONFIG_ZSTD
> + case QCOW2_COMPRESSION_TYPE_ZSTD:
> + break;
> +#endif
> default:
> error_setg(errp, "Unknown compression type");
> goto out;
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v11 3/4] qcow2: add zstd cluster compression
2020-03-30 13:14 ` Vladimir Sementsov-Ogievskiy
@ 2020-03-30 15:04 ` Denis Plotnikov
2020-03-31 6:22 ` Vladimir Sementsov-Ogievskiy
0 siblings, 1 reply; 12+ messages in thread
From: Denis Plotnikov @ 2020-03-30 15:04 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-devel
Cc: kwolf, berto, qemu-block, armbru, mreitz, den
On 30.03.2020 16:14, Vladimir Sementsov-Ogievskiy wrote:
> 30.03.2020 12:54, Denis Plotnikov wrote:
>> zstd significantly reduces cluster compression time.
>> It provides better compression performance maintaining
>> the same level of the compression ratio in comparison with
>> zlib, which, at the moment, is 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>
>> QAPI part:
>> Acked-by: Markus Armbruster <armbru@redhat.com>
>> ---
>> docs/interop/qcow2.txt | 1 +
>> configure | 2 +-
>> qapi/block-core.json | 3 +-
>> block/qcow2-threads.c | 138 +++++++++++++++++++++++++++++++++++++++++
>> block/qcow2.c | 7 +++
>> 5 files changed, 149 insertions(+), 2 deletions(-)
>>
>> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
>> index 5597e24474..795dbb21dd 100644
>> --- a/docs/interop/qcow2.txt
>> +++ b/docs/interop/qcow2.txt
>> @@ -208,6 +208,7 @@ version 2.
>> Available compression type values:
>> 0: zlib <https://www.zlib.net/>
>> + 1: zstd <http://github.com/facebook/zstd>
>> === Header padding ===
>> diff --git a/configure b/configure
>> index da09c35895..57cac2abe1 100755
>> --- a/configure
>> +++ b/configure
>> @@ -1861,7 +1861,7 @@ disabled with --disable-FEATURE, default is
>> enabled if available:
>> lzfse support of lzfse compression library
>> (for reading lzfse-compressed dmg images)
>> zstd support for zstd compression library
>> - (for migration compression)
>> + (for migration compression and qcow2 cluster
>> compression)
>> seccomp seccomp support
>> coroutine-pool coroutine freelist (better performance)
>> glusterfs GlusterFS backend
>> diff --git a/qapi/block-core.json b/qapi/block-core.json
>> index d669ec0965..44690ed266 100644
>> --- a/qapi/block-core.json
>> +++ b/qapi/block-core.json
>> @@ -4293,11 +4293,12 @@
>> # Compression type used in qcow2 image file
>> #
>> # @zlib: zlib compression, see <http://zlib.net/>
>> +# @zstd: zstd compression, see <http://github.com/facebook/zstd>
>> #
>> # Since: 5.0
>> ##
>> { 'enum': 'Qcow2CompressionType',
>> - 'data': [ 'zlib' ] }
>> + 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' }
>> ] }
>> ##
>> # @BlockdevCreateOptionsQcow2:
>> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
>> index 7dbaf53489..b8ccd97009 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"
>> @@ -166,6 +171,129 @@ 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)
>> +{
>> + size_t ret;
>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>> + ZSTD_inBuffer input = { src, src_size, 0 };
>> + ZSTD_CCtx *cctx = ZSTD_createCCtx();
>> +
>> + if (!cctx) {
>> + return -EIO;
>> + }
>> + /*
>> + * ZSTD spec: "You must continue calling ZSTD_compressStream2()
>> + * with ZSTD_e_end until it returns 0, at which point you are
>> + * free to start a new frame".
>> + * In the loop, we try to compress all the data into one zstd
>> frame.
>> + * ZSTD_compressStream2 can potentially finish a frame earlier
>> + * than the full input data is consumed. That's why we are looping
>> + * until all the input data is consumed.
>> + */
>> + while (input.pos < input.size) {
>> + /*
>> + * zstd simple interface requires the exact compressed size.
>
> on decompression you mean
>
>> + * zstd stream interface reads the comressed size from
>> + * the compressed stream frame.
>
> compressed size is not stored in the stream. I think, that streamed
> interface just decompress until it have something to decompress and
> have space to write output.
>
>> + * Instruct zstd to compress the whole buffer and write
>> + * the frame which includes the compressed size.
>
> I think this is wrong. compression size is not written.
Ok
>
>> + * This allows as to use zstd streaming semantics and
>> + * don't store the compressed size for the zstd decompression.
>> + */
>
> Comment is just outdated. Accordingly to our off-list discussion, I'd
> rewrite it like this:
>
> We want to use streamed interface on decompression, as we will not know
> exact size of compression data.
This one is better then mine.
> Use streamed interface for compression
> just for symmetry.
I think this one is exceeding. If we have stream family functions on
both sides this won't rise any questions from the reader.
>
>
>> + ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);
>> + if (ZSTD_isError(ret)) {
>> + ret = -EIO;
>> + goto out;
>> + }
>> + /* Dest buffer isn't big enough to store compressed content */
>> + if (output.pos + ret > output.size) {
>> + ret = -ENOMEM;
>> + goto out;
>> + }
>
> Here you use "@return provides a minimum amount of data remaining to
> be flushed from internal buffers
> or an error code, which can be tested using ZSTD_isError()."
>
> I think we can safely drop this check
No, we can't.
we should check for if zstd managed to write the stream correctly.
ZSTD_compressStream2 may consume all the input buffer but return ret > 0
meaning that it needs more space.
This is from my tests:
(gdb) p ret
$1 = 11
(gdb) p input
$2 = {src = 0x562305536000, size = 65536, pos = 65536}
(gdb) p output
$3 = {dst = 0x562305546000, size = 65535, pos = 65535}
Alternatively, we can replace the check with something like
if (ret != 0) {
ret = -ENOMEM;
}
after the loop, but I think both are equivalent, so I would stick with
my one :)))
> work anyway.
>
>> + };
>> +
>> + /* make sure we can safely return compressed buffer size with
>> ssize_t */
>> + assert(output.pos <= SSIZE_MAX);
>
> Hmm. I hope it's not possible for cluster. But taking the function in
> separate, it _is_ possible.
> So may be better to assert at function start that
>
> assert(dest_size <= SSIZE_MAX);
>
> To stress, that this limitation is part of qcow2_zstd_compress()
> interface.
Agree, this is better
>
>> + ret = output.pos;
>> +
>> +out:
>> + ZSTD_freeCCtx(cctx);
>> + return ret;
>> +}
>> +
>> +/*
>> + * 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)
>> +{
>> + size_t ret = 0;
>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>> + ZSTD_inBuffer input = { src, src_size, 0 };
>> + ZSTD_DCtx *dctx = ZSTD_createDCtx();
>> +
>> + if (!dctx) {
>> + return -EIO;
>> + }
>> +
>> + /*
>> + * The compressed stream from input buffer may consist from more
>> + * than one zstd frames. So we iterate until we get a fully
>> + * uncompressed cluster.
>> + */
>> + while (output.pos < output.size) {
>> + ret = ZSTD_decompressStream(dctx, &output, &input);
>> + /*
>> + * if we don't fully populate the output but have read
>> + * all the frames from the input, we end up with error
>> + * here
>> + */
>> + if (ZSTD_isError(ret)) {
>> + ret = -EIO;
>> + break;
>> + }
>> + /*
>> + * Dest buffer size is the image cluster size.
>> + * It should be big enough to store uncompressed content.
>> + * There shouldn't be any cases when the decompressed content
>> + * size is greater then the cluster size, except cluster
>> + * damaging.
>> + */
>> + if (output.pos + ret > output.size) {
>> + ret = -EIO;
>> + break;
>> + }
>
> But here, you use
> "
> or any other value > 0, which means there is still some decoding or
> flushing to do to complete current frame :
> the return value is a suggested next
> input size (just a hint for better latency)
> that will never request more than the
> remaining frame size.
> "
>
> I'm afraid that "just a hint" is not safe API to make a conclusion
> from. So, I'd prefer to drop this optimization
> and just wait for an error from next ZSTD_decompressStream.
>
> And therefore, for symmetry drop similar optimization on compression
> part..
>
> What do you think?
I'd add some kind of check that we have finished with ret==0 (after
loop). It looks like this is the only case when we can be sure that
everything went ok.
>
>
>> + }
>> +
>> + ZSTD_freeDCtx(dctx);
>> + return ret;
>> +}
>> +#endif
>> +
>> static int qcow2_compress_pool_func(void *opaque)
>> {
>> Qcow2CompressData *data = opaque;
>> @@ -217,6 +345,11 @@ 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:
>> abort();
>> }
>> @@ -249,6 +382,11 @@ 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:
>> abort();
>> }
>> diff --git a/block/qcow2.c b/block/qcow2.c
>> index 643698934d..6632daf50b 100644
>> --- a/block/qcow2.c
>> +++ b/block/qcow2.c
>> @@ -1246,6 +1246,9 @@ static int
>> validate_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:
>> @@ -3461,6 +3464,10 @@ qcow2_co_create(BlockdevCreateOptions
>> *create_options, Error **errp)
>> }
>> switch (qcow2_opts->compression_type) {
>> +#ifdef CONFIG_ZSTD
>> + case QCOW2_COMPRESSION_TYPE_ZSTD:
>> + break;
>> +#endif
>> default:
>> error_setg(errp, "Unknown compression type");
>> goto out;
>>
>
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v11 3/4] qcow2: add zstd cluster compression
2020-03-30 15:04 ` Denis Plotnikov
@ 2020-03-31 6:22 ` Vladimir Sementsov-Ogievskiy
2020-03-31 7:55 ` Denis Plotnikov
0 siblings, 1 reply; 12+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-03-31 6:22 UTC (permalink / raw)
To: Denis Plotnikov, qemu-devel; +Cc: kwolf, berto, qemu-block, armbru, mreitz, den
30.03.2020 18:04, Denis Plotnikov wrote:
>
>
> On 30.03.2020 16:14, Vladimir Sementsov-Ogievskiy wrote:
>> 30.03.2020 12:54, Denis Plotnikov wrote:
>>> zstd significantly reduces cluster compression time.
>>> It provides better compression performance maintaining
>>> the same level of the compression ratio in comparison with
>>> zlib, which, at the moment, is 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>
>>> QAPI part:
>>> Acked-by: Markus Armbruster <armbru@redhat.com>
>>> ---
>>> docs/interop/qcow2.txt | 1 +
>>> configure | 2 +-
>>> qapi/block-core.json | 3 +-
>>> block/qcow2-threads.c | 138 +++++++++++++++++++++++++++++++++++++++++
>>> block/qcow2.c | 7 +++
>>> 5 files changed, 149 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
>>> index 5597e24474..795dbb21dd 100644
>>> --- a/docs/interop/qcow2.txt
>>> +++ b/docs/interop/qcow2.txt
>>> @@ -208,6 +208,7 @@ version 2.
>>> Available compression type values:
>>> 0: zlib <https://www.zlib.net/>
>>> + 1: zstd <http://github.com/facebook/zstd>
>>> === Header padding ===
>>> diff --git a/configure b/configure
>>> index da09c35895..57cac2abe1 100755
>>> --- a/configure
>>> +++ b/configure
>>> @@ -1861,7 +1861,7 @@ disabled with --disable-FEATURE, default is enabled if available:
>>> lzfse support of lzfse compression library
>>> (for reading lzfse-compressed dmg images)
>>> zstd support for zstd compression library
>>> - (for migration compression)
>>> + (for migration compression and qcow2 cluster compression)
>>> seccomp seccomp support
>>> coroutine-pool coroutine freelist (better performance)
>>> glusterfs GlusterFS backend
>>> diff --git a/qapi/block-core.json b/qapi/block-core.json
>>> index d669ec0965..44690ed266 100644
>>> --- a/qapi/block-core.json
>>> +++ b/qapi/block-core.json
>>> @@ -4293,11 +4293,12 @@
>>> # Compression type used in qcow2 image file
>>> #
>>> # @zlib: zlib compression, see <http://zlib.net/>
>>> +# @zstd: zstd compression, see <http://github.com/facebook/zstd>
>>> #
>>> # Since: 5.0
>>> ##
>>> { 'enum': 'Qcow2CompressionType',
>>> - 'data': [ 'zlib' ] }
>>> + 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] }
>>> ##
>>> # @BlockdevCreateOptionsQcow2:
>>> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
>>> index 7dbaf53489..b8ccd97009 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"
>>> @@ -166,6 +171,129 @@ 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)
>>> +{
>>> + size_t ret;
>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>> + ZSTD_CCtx *cctx = ZSTD_createCCtx();
>>> +
>>> + if (!cctx) {
>>> + return -EIO;
>>> + }
>>> + /*
>>> + * ZSTD spec: "You must continue calling ZSTD_compressStream2()
>>> + * with ZSTD_e_end until it returns 0, at which point you are
>>> + * free to start a new frame".
>>> + * In the loop, we try to compress all the data into one zstd frame.
>>> + * ZSTD_compressStream2 can potentially finish a frame earlier
>>> + * than the full input data is consumed. That's why we are looping
>>> + * until all the input data is consumed.
>>> + */
>>> + while (input.pos < input.size) {
>>> + /*
>>> + * zstd simple interface requires the exact compressed size.
>>
>> on decompression you mean
>>
>>> + * zstd stream interface reads the comressed size from
>>> + * the compressed stream frame.
>>
>> compressed size is not stored in the stream. I think, that streamed
>> interface just decompress until it have something to decompress and
>> have space to write output.
>>
>>> + * Instruct zstd to compress the whole buffer and write
>>> + * the frame which includes the compressed size.
>>
>> I think this is wrong. compression size is not written.
> Ok
>>
>>> + * This allows as to use zstd streaming semantics and
>>> + * don't store the compressed size for the zstd decompression.
>>> + */
>>
>> Comment is just outdated. Accordingly to our off-list discussion, I'd
>> rewrite it like this:
>>
>> We want to use streamed interface on decompression, as we will not know
>> exact size of compression data.
> This one is better then mine.
>> Use streamed interface for compression
>> just for symmetry.
> I think this one is exceeding. If we have stream family functions on both sides this won't rise any questions from the reader.
>
>>
>>
>>> + ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);
>>> + if (ZSTD_isError(ret)) {
>>> + ret = -EIO;
>>> + goto out;
>>> + }
>>> + /* Dest buffer isn't big enough to store compressed content */
>>> + if (output.pos + ret > output.size) {
>>> + ret = -ENOMEM;
>>> + goto out;
>>> + }
>>
>> Here you use "@return provides a minimum amount of data remaining to be flushed from internal buffers
>> or an error code, which can be tested using ZSTD_isError()."
>>
>> I think we can safely drop this check
> No, we can't.
> we should check for if zstd managed to write the stream correctly. ZSTD_compressStream2 may consume all the input buffer but return ret > 0 meaning that it needs more space.
Hmm, interesting thing. But your check doesn't protect us from it:
Assume we have
output.size = input.size = 64K
output.pos = 64K
input.pos = 10K
ret = 10K
- which means that all input is consumed, but we have some cached data (at least 10K) to flush.
10K + 10K = 20K < 64K, so your check will no lead to an error, but we'll exit the loop..
So, actually, what we need it two things:
1. input.pos = input.size, which means that all input is consumed
2. ret = 0, which means that all cached data flushed
So we need something like
do {
ret = ZSTD_compressStream2(cctx, &output, &input, ZDTD_e_end)
if (ZSTD_isError(ret)) {
ret = -EIO.
goto out;
}
} while (ret || input.pos < input.size);
>
> This is from my tests:
>
> (gdb) p ret
> $1 = 11
> (gdb) p input
> $2 = {src = 0x562305536000, size = 65536, pos = 65536}
> (gdb) p output
> $3 = {dst = 0x562305546000, size = 65535, pos = 65535}
>
> Alternatively, we can replace the check with something like
>
> if (ret != 0) {
> ret = -ENOMEM;
> }
It's not correct either, it's not an error: it just means that we need to flush a bit more data.
>
> after the loop, but I think both are equivalent, so I would stick with my one :)))
>> work anyway.
>>
>>> + };
>>> +
>>> + /* make sure we can safely return compressed buffer size with ssize_t */
>>> + assert(output.pos <= SSIZE_MAX);
>>
>> Hmm. I hope it's not possible for cluster. But taking the function in separate, it _is_ possible.
>> So may be better to assert at function start that
>>
>> assert(dest_size <= SSIZE_MAX);
>>
>> To stress, that this limitation is part of qcow2_zstd_compress() interface.
> Agree, this is better
>>
>>> + ret = output.pos;
>>> +
>>> +out:
>>> + ZSTD_freeCCtx(cctx);
>>> + return ret;
>>> +}
>>> +
>>> +/*
>>> + * 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)
>>> +{
>>> + size_t ret = 0;
>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>> + ZSTD_DCtx *dctx = ZSTD_createDCtx();
>>> +
>>> + if (!dctx) {
>>> + return -EIO;
>>> + }
>>> +
>>> + /*
>>> + * The compressed stream from input buffer may consist from more
>>> + * than one zstd frames. So we iterate until we get a fully
>>> + * uncompressed cluster.
>>> + */
>>> + while (output.pos < output.size) {
>>> + ret = ZSTD_decompressStream(dctx, &output, &input);
>>> + /*
>>> + * if we don't fully populate the output but have read
>>> + * all the frames from the input, we end up with error
>>> + * here
>>> + */
>>> + if (ZSTD_isError(ret)) {
>>> + ret = -EIO;
>>> + break;
>>> + }
>>> + /*
>>> + * Dest buffer size is the image cluster size.
>>> + * It should be big enough to store uncompressed content.
>>> + * There shouldn't be any cases when the decompressed content
>>> + * size is greater then the cluster size, except cluster
>>> + * damaging.
>>> + */
>>> + if (output.pos + ret > output.size) {
>>> + ret = -EIO;
>>> + break;
>>> + }
>>
>> But here, you use
>> "
>> or any other value > 0, which means there is still some decoding or flushing to do to complete current frame :
>> the return value is a suggested next input size (just a hint for better latency)
>> that will never request more than the remaining frame size.
>> "
>>
>> I'm afraid that "just a hint" is not safe API to make a conclusion from. So, I'd prefer to drop this optimization
>> and just wait for an error from next ZSTD_decompressStream.
>>
>> And therefore, for symmetry drop similar optimization on compression part..
>>
>> What do you think?
> I'd add some kind of check that we have finished with ret==0 (after loop). It looks like this is the only case when we can be sure that everything went ok.
I think, we should not check it. It is possible that compressed data of another cluster is starting below input end. Is it guaranteed that ZSTD_decompressStream will not start to decompress (or at least plan to do it) the next frame, which is unrelated to our cluster? I'm afraid it's not guaranteed, so we can get ret>0 when output.pos=output.size in correct situation. So I think it's safer not to add this final check for ret. Note that we are not protected from wrong data anyway.
>>
>>
>>> + }
>>> +
>>> + ZSTD_freeDCtx(dctx);
>>> + return ret;
>>> +}
>>> +#endif
>>> +
>>> static int qcow2_compress_pool_func(void *opaque)
>>> {
>>> Qcow2CompressData *data = opaque;
>>> @@ -217,6 +345,11 @@ 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:
>>> abort();
>>> }
>>> @@ -249,6 +382,11 @@ 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:
>>> abort();
>>> }
>>> diff --git a/block/qcow2.c b/block/qcow2.c
>>> index 643698934d..6632daf50b 100644
>>> --- a/block/qcow2.c
>>> +++ b/block/qcow2.c
>>> @@ -1246,6 +1246,9 @@ static int validate_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:
>>> @@ -3461,6 +3464,10 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
>>> }
>>> switch (qcow2_opts->compression_type) {
>>> +#ifdef CONFIG_ZSTD
>>> + case QCOW2_COMPRESSION_TYPE_ZSTD:
>>> + break;
>>> +#endif
>>> default:
>>> error_setg(errp, "Unknown compression type");
>>> goto out;
>>>
>>
>>
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v11 3/4] qcow2: add zstd cluster compression
2020-03-31 6:22 ` Vladimir Sementsov-Ogievskiy
@ 2020-03-31 7:55 ` Denis Plotnikov
2020-03-31 8:10 ` Vladimir Sementsov-Ogievskiy
0 siblings, 1 reply; 12+ messages in thread
From: Denis Plotnikov @ 2020-03-31 7:55 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-devel
Cc: kwolf, berto, qemu-block, armbru, mreitz, den
On 31.03.2020 09:22, Vladimir Sementsov-Ogievskiy wrote:
> 30.03.2020 18:04, Denis Plotnikov wrote:
>>
>>
>> On 30.03.2020 16:14, Vladimir Sementsov-Ogievskiy wrote:
>>> 30.03.2020 12:54, Denis Plotnikov wrote:
>>>> zstd significantly reduces cluster compression time.
>>>> It provides better compression performance maintaining
>>>> the same level of the compression ratio in comparison with
>>>> zlib, which, at the moment, is 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>
>>>> QAPI part:
>>>> Acked-by: Markus Armbruster <armbru@redhat.com>
>>>> ---
>>>> docs/interop/qcow2.txt | 1 +
>>>> configure | 2 +-
>>>> qapi/block-core.json | 3 +-
>>>> block/qcow2-threads.c | 138
>>>> +++++++++++++++++++++++++++++++++++++++++
>>>> block/qcow2.c | 7 +++
>>>> 5 files changed, 149 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
>>>> index 5597e24474..795dbb21dd 100644
>>>> --- a/docs/interop/qcow2.txt
>>>> +++ b/docs/interop/qcow2.txt
>>>> @@ -208,6 +208,7 @@ version 2.
>>>> Available compression type values:
>>>> 0: zlib <https://www.zlib.net/>
>>>> + 1: zstd <http://github.com/facebook/zstd>
>>>> === Header padding ===
>>>> diff --git a/configure b/configure
>>>> index da09c35895..57cac2abe1 100755
>>>> --- a/configure
>>>> +++ b/configure
>>>> @@ -1861,7 +1861,7 @@ disabled with --disable-FEATURE, default is
>>>> enabled if available:
>>>> lzfse support of lzfse compression library
>>>> (for reading lzfse-compressed dmg images)
>>>> zstd support for zstd compression library
>>>> - (for migration compression)
>>>> + (for migration compression and qcow2 cluster
>>>> compression)
>>>> seccomp seccomp support
>>>> coroutine-pool coroutine freelist (better performance)
>>>> glusterfs GlusterFS backend
>>>> diff --git a/qapi/block-core.json b/qapi/block-core.json
>>>> index d669ec0965..44690ed266 100644
>>>> --- a/qapi/block-core.json
>>>> +++ b/qapi/block-core.json
>>>> @@ -4293,11 +4293,12 @@
>>>> # Compression type used in qcow2 image file
>>>> #
>>>> # @zlib: zlib compression, see <http://zlib.net/>
>>>> +# @zstd: zstd compression, see <http://github.com/facebook/zstd>
>>>> #
>>>> # Since: 5.0
>>>> ##
>>>> { 'enum': 'Qcow2CompressionType',
>>>> - 'data': [ 'zlib' ] }
>>>> + 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)'
>>>> } ] }
>>>> ##
>>>> # @BlockdevCreateOptionsQcow2:
>>>> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
>>>> index 7dbaf53489..b8ccd97009 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"
>>>> @@ -166,6 +171,129 @@ 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)
>>>> +{
>>>> + size_t ret;
>>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>>> + ZSTD_CCtx *cctx = ZSTD_createCCtx();
>>>> +
>>>> + if (!cctx) {
>>>> + return -EIO;
>>>> + }
>>>> + /*
>>>> + * ZSTD spec: "You must continue calling ZSTD_compressStream2()
>>>> + * with ZSTD_e_end until it returns 0, at which point you are
>>>> + * free to start a new frame".
>>>> + * In the loop, we try to compress all the data into one zstd
>>>> frame.
>>>> + * ZSTD_compressStream2 can potentially finish a frame earlier
>>>> + * than the full input data is consumed. That's why we are
>>>> looping
>>>> + * until all the input data is consumed.
>>>> + */
>>>> + while (input.pos < input.size) {
>>>> + /*
>>>> + * zstd simple interface requires the exact compressed size.
>>>
>>> on decompression you mean
>>>
>>>> + * zstd stream interface reads the comressed size from
>>>> + * the compressed stream frame.
>>>
>>> compressed size is not stored in the stream. I think, that streamed
>>> interface just decompress until it have something to decompress and
>>> have space to write output.
>>>
>>>> + * Instruct zstd to compress the whole buffer and write
>>>> + * the frame which includes the compressed size.
>>>
>>> I think this is wrong. compression size is not written.
>> Ok
>>>
>>>> + * This allows as to use zstd streaming semantics and
>>>> + * don't store the compressed size for the zstd
>>>> decompression.
>>>> + */
>>>
>>> Comment is just outdated. Accordingly to our off-list discussion, I'd
>>> rewrite it like this:
>>>
>>> We want to use streamed interface on decompression, as we will not know
>>> exact size of compression data.
>> This one is better then mine.
>>> Use streamed interface for compression
>>> just for symmetry.
>> I think this one is exceeding. If we have stream family functions on
>> both sides this won't rise any questions from the reader.
>>
>>>
>>>
>>>> + ret = ZSTD_compressStream2(cctx, &output, &input,
>>>> ZSTD_e_end);
>>>> + if (ZSTD_isError(ret)) {
>>>> + ret = -EIO;
>>>> + goto out;
>>>> + }
>>>> + /* Dest buffer isn't big enough to store compressed
>>>> content */
>>>> + if (output.pos + ret > output.size) {
>>>> + ret = -ENOMEM;
>>>> + goto out;
>>>> + }
>>>
>>> Here you use "@return provides a minimum amount of data remaining to
>>> be flushed from internal buffers
>>> or an error code, which can be tested using
>>> ZSTD_isError()."
>>>
>>> I think we can safely drop this check
>> No, we can't.
>> we should check for if zstd managed to write the stream correctly.
>> ZSTD_compressStream2 may consume all the input buffer but return ret
>> > 0 meaning that it needs more space.
>
> Hmm, interesting thing. But your check doesn't protect us from it:
>
> Assume we have
>
> output.size = input.size = 64K
> output.pos = 64K
> input.pos = 10K
> ret = 10K
>
> - which means that all input is consumed, but we have some cached data
> (at least 10K) to flush.
>
> 10K + 10K = 20K < 64K, so your check will no lead to an error, but
> we'll exit the loop..
No, it does protect
you use incorrect formula: _input_.pos + ret < output.size
but the code is
if (output.pos + ret > output.size) {
ret = -ENOMEM;
goto out;
}
so, 64K + 10K = 74K -> 74K > 64K (true) -> ret = -ENOMEM
>
> So, actually, what we need it two things:
>
> 1. input.pos = input.size, which means that all input is consumed
> 2. ret = 0, which means that all cached data flushed
>
> So we need something like
>
> do {
> ret = ZSTD_compressStream2(cctx, &output, &input, ZDTD_e_end)
> if (ZSTD_isError(ret)) {
> ret = -EIO.
> goto out;
> }
> } while (ret || input.pos < input.size);
>
>>
>> This is from my tests:
>>
>> (gdb) p ret
>> $1 = 11
>> (gdb) p input
>> $2 = {src = 0x562305536000, size = 65536, pos = 65536}
>> (gdb) p output
>> $3 = {dst = 0x562305546000, size = 65535, pos = 65535}
>>
>> Alternatively, we can replace the check with something like
>>
>> if (ret != 0) {
>> ret = -ENOMEM;
>> }
>
> It's not correct either, it's not an error: it just means that we need
> to flush a bit more data.
.. but we don't have space to do it, so it looks like -ENOMEM
>
>>
>> after the loop, but I think both are equivalent, so I would stick
>> with my one :)))
>>> work anyway.
>>>
>>>> + };
>>>> +
>>>> + /* make sure we can safely return compressed buffer size with
>>>> ssize_t */
>>>> + assert(output.pos <= SSIZE_MAX);
>>>
>>> Hmm. I hope it's not possible for cluster. But taking the function
>>> in separate, it _is_ possible.
>>> So may be better to assert at function start that
>>>
>>> assert(dest_size <= SSIZE_MAX);
>>>
>>> To stress, that this limitation is part of qcow2_zstd_compress()
>>> interface.
>> Agree, this is better
>>>
>>>> + ret = output.pos;
>>>> +
>>>> +out:
>>>> + ZSTD_freeCCtx(cctx);
>>>> + return ret;
>>>> +}
>>>> +
>>>> +/*
>>>> + * 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)
>>>> +{
>>>> + size_t ret = 0;
>>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>>> + ZSTD_DCtx *dctx = ZSTD_createDCtx();
>>>> +
>>>> + if (!dctx) {
>>>> + return -EIO;
>>>> + }
>>>> +
>>>> + /*
>>>> + * The compressed stream from input buffer may consist from more
>>>> + * than one zstd frames. So we iterate until we get a fully
>>>> + * uncompressed cluster.
>>>> + */
>>>> + while (output.pos < output.size) {
>>>> + ret = ZSTD_decompressStream(dctx, &output, &input);
>>>> + /*
>>>> + * if we don't fully populate the output but have read
>>>> + * all the frames from the input, we end up with error
>>>> + * here
>>>> + */
>>>> + if (ZSTD_isError(ret)) {
>>>> + ret = -EIO;
>>>> + break;
>>>> + }
>>>> + /*
>>>> + * Dest buffer size is the image cluster size.
>>>> + * It should be big enough to store uncompressed content.
>>>> + * There shouldn't be any cases when the decompressed content
>>>> + * size is greater then the cluster size, except cluster
>>>> + * damaging.
>>>> + */
>>>> + if (output.pos + ret > output.size) {
>>>> + ret = -EIO;
>>>> + break;
>>>> + }
>>>
>>> But here, you use
>>> "
>>> or any other value > 0, which means there is still some decoding or
>>> flushing to do to complete current frame :
>>> the return value is a suggested next
>>> input size (just a hint for better latency)
>>> that will never request more than
>>> the remaining frame size.
>>> "
>>>
>>> I'm afraid that "just a hint" is not safe API to make a conclusion
>>> from. So, I'd prefer to drop this optimization
>>> and just wait for an error from next ZSTD_decompressStream.
>>>
>>> And therefore, for symmetry drop similar optimization on compression
>>> part..
>>>
>>> What do you think?
>> I'd add some kind of check that we have finished with ret==0 (after
>> loop). It looks like this is the only case when we can be sure that
>> everything went ok.
>
> I think, we should not check it. It is possible that compressed data
> of another cluster is starting below input end. Is it guaranteed that
> ZSTD_decompressStream will not start to decompress (or at least plan
> to do it) the next frame, which is unrelated to our cluster? I'm
> afraid it's not guaranteed, so we can get ret>0 when
> output.pos=output.size in correct situation. So I think it's safer not
> to add this final check for ret. Note that we are not protected from
> wrong data anyway.
Looking at zlib_compress implementation, yes it seems to be, so.
Ok, I'll drop the check.
>
>>>
>>>
>>>> + }
>>>> +
>>>> + ZSTD_freeDCtx(dctx);
>>>> + return ret;
>>>> +}
>>>> +#endif
>>>> +
>>>> static int qcow2_compress_pool_func(void *opaque)
>>>> {
>>>> Qcow2CompressData *data = opaque;
>>>> @@ -217,6 +345,11 @@ 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:
>>>> abort();
>>>> }
>>>> @@ -249,6 +382,11 @@ 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:
>>>> abort();
>>>> }
>>>> diff --git a/block/qcow2.c b/block/qcow2.c
>>>> index 643698934d..6632daf50b 100644
>>>> --- a/block/qcow2.c
>>>> +++ b/block/qcow2.c
>>>> @@ -1246,6 +1246,9 @@ static int
>>>> validate_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:
>>>> @@ -3461,6 +3464,10 @@ qcow2_co_create(BlockdevCreateOptions
>>>> *create_options, Error **errp)
>>>> }
>>>> switch (qcow2_opts->compression_type) {
>>>> +#ifdef CONFIG_ZSTD
>>>> + case QCOW2_COMPRESSION_TYPE_ZSTD:
>>>> + break;
>>>> +#endif
>>>> default:
>>>> error_setg(errp, "Unknown compression type");
>>>> goto out;
>>>>
>>>
>>>
>>
>
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v11 3/4] qcow2: add zstd cluster compression
2020-03-31 7:55 ` Denis Plotnikov
@ 2020-03-31 8:10 ` Vladimir Sementsov-Ogievskiy
2020-03-31 8:34 ` Denis Plotnikov
0 siblings, 1 reply; 12+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-03-31 8:10 UTC (permalink / raw)
To: Denis Plotnikov, qemu-devel; +Cc: kwolf, berto, qemu-block, armbru, mreitz, den
31.03.2020 10:55, Denis Plotnikov wrote:
>
>
> On 31.03.2020 09:22, Vladimir Sementsov-Ogievskiy wrote:
>> 30.03.2020 18:04, Denis Plotnikov wrote:
>>>
>>>
>>> On 30.03.2020 16:14, Vladimir Sementsov-Ogievskiy wrote:
>>>> 30.03.2020 12:54, Denis Plotnikov wrote:
>>>>> zstd significantly reduces cluster compression time.
>>>>> It provides better compression performance maintaining
>>>>> the same level of the compression ratio in comparison with
>>>>> zlib, which, at the moment, is 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>
>>>>> QAPI part:
>>>>> Acked-by: Markus Armbruster <armbru@redhat.com>
>>>>> ---
>>>>> docs/interop/qcow2.txt | 1 +
>>>>> configure | 2 +-
>>>>> qapi/block-core.json | 3 +-
>>>>> block/qcow2-threads.c | 138 +++++++++++++++++++++++++++++++++++++++++
>>>>> block/qcow2.c | 7 +++
>>>>> 5 files changed, 149 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
>>>>> index 5597e24474..795dbb21dd 100644
>>>>> --- a/docs/interop/qcow2.txt
>>>>> +++ b/docs/interop/qcow2.txt
>>>>> @@ -208,6 +208,7 @@ version 2.
>>>>> Available compression type values:
>>>>> 0: zlib <https://www.zlib.net/>
>>>>> + 1: zstd <http://github.com/facebook/zstd>
>>>>> === Header padding ===
>>>>> diff --git a/configure b/configure
>>>>> index da09c35895..57cac2abe1 100755
>>>>> --- a/configure
>>>>> +++ b/configure
>>>>> @@ -1861,7 +1861,7 @@ disabled with --disable-FEATURE, default is enabled if available:
>>>>> lzfse support of lzfse compression library
>>>>> (for reading lzfse-compressed dmg images)
>>>>> zstd support for zstd compression library
>>>>> - (for migration compression)
>>>>> + (for migration compression and qcow2 cluster compression)
>>>>> seccomp seccomp support
>>>>> coroutine-pool coroutine freelist (better performance)
>>>>> glusterfs GlusterFS backend
>>>>> diff --git a/qapi/block-core.json b/qapi/block-core.json
>>>>> index d669ec0965..44690ed266 100644
>>>>> --- a/qapi/block-core.json
>>>>> +++ b/qapi/block-core.json
>>>>> @@ -4293,11 +4293,12 @@
>>>>> # Compression type used in qcow2 image file
>>>>> #
>>>>> # @zlib: zlib compression, see <http://zlib.net/>
>>>>> +# @zstd: zstd compression, see <http://github.com/facebook/zstd>
>>>>> #
>>>>> # Since: 5.0
>>>>> ##
>>>>> { 'enum': 'Qcow2CompressionType',
>>>>> - 'data': [ 'zlib' ] }
>>>>> + 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] }
>>>>> ##
>>>>> # @BlockdevCreateOptionsQcow2:
>>>>> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
>>>>> index 7dbaf53489..b8ccd97009 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"
>>>>> @@ -166,6 +171,129 @@ 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)
>>>>> +{
>>>>> + size_t ret;
>>>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>>>> + ZSTD_CCtx *cctx = ZSTD_createCCtx();
>>>>> +
>>>>> + if (!cctx) {
>>>>> + return -EIO;
>>>>> + }
>>>>> + /*
>>>>> + * ZSTD spec: "You must continue calling ZSTD_compressStream2()
>>>>> + * with ZSTD_e_end until it returns 0, at which point you are
>>>>> + * free to start a new frame".
>>>>> + * In the loop, we try to compress all the data into one zstd frame.
>>>>> + * ZSTD_compressStream2 can potentially finish a frame earlier
>>>>> + * than the full input data is consumed. That's why we are looping
>>>>> + * until all the input data is consumed.
>>>>> + */
>>>>> + while (input.pos < input.size) {
>>>>> + /*
>>>>> + * zstd simple interface requires the exact compressed size.
>>>>
>>>> on decompression you mean
>>>>
>>>>> + * zstd stream interface reads the comressed size from
>>>>> + * the compressed stream frame.
>>>>
>>>> compressed size is not stored in the stream. I think, that streamed
>>>> interface just decompress until it have something to decompress and
>>>> have space to write output.
>>>>
>>>>> + * Instruct zstd to compress the whole buffer and write
>>>>> + * the frame which includes the compressed size.
>>>>
>>>> I think this is wrong. compression size is not written.
>>> Ok
>>>>
>>>>> + * This allows as to use zstd streaming semantics and
>>>>> + * don't store the compressed size for the zstd decompression.
>>>>> + */
>>>>
>>>> Comment is just outdated. Accordingly to our off-list discussion, I'd
>>>> rewrite it like this:
>>>>
>>>> We want to use streamed interface on decompression, as we will not know
>>>> exact size of compression data.
>>> This one is better then mine.
>>>> Use streamed interface for compression
>>>> just for symmetry.
>>> I think this one is exceeding. If we have stream family functions on both sides this won't rise any questions from the reader.
>>>
>>>>
>>>>
>>>>> + ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);
>>>>> + if (ZSTD_isError(ret)) {
>>>>> + ret = -EIO;
>>>>> + goto out;
>>>>> + }
>>>>> + /* Dest buffer isn't big enough to store compressed content */
>>>>> + if (output.pos + ret > output.size) {
>>>>> + ret = -ENOMEM;
>>>>> + goto out;
>>>>> + }
>>>>
>>>> Here you use "@return provides a minimum amount of data remaining to be flushed from internal buffers
>>>> or an error code, which can be tested using ZSTD_isError()."
>>>>
>>>> I think we can safely drop this check
>>> No, we can't.
>>> we should check for if zstd managed to write the stream correctly. ZSTD_compressStream2 may consume all the input buffer but return ret > 0 meaning that it needs more space.
>>
>> Hmm, interesting thing. But your check doesn't protect us from it:
>>
>> Assume we have
>>
>> output.size = input.size = 64K
>> output.pos = 64K
>> input.pos = 10K
>> ret = 10K
>>
>> - which means that all input is consumed, but we have some cached data (at least 10K) to flush.
>>
>> 10K + 10K = 20K < 64K, so your check will no lead to an error, but we'll exit the loop..
> No, it does protect
> you use incorrect formula: _input_.pos + ret < output.size
>
> but the code is
>
> if (output.pos + ret > output.size) {
> ret = -ENOMEM;
> goto out;
> }
>
> so, 64K + 10K = 74K -> 74K > 64K (true) -> ret = -ENOMEM
Oops, than another example:
output.size = input.size = 64K
output.pos = 40K
input.pos = 64K
ret = 10K
your check doesn't catch it, and it's not an error. But we exit the loop (because input.pos == input.size) and don't write last 10K.
>
>>
>> So, actually, what we need it two things:
>>
>> 1. input.pos = input.size, which means that all input is consumed
>> 2. ret = 0, which means that all cached data flushed
>>
>> So we need something like
>>
>> do {
>> ret = ZSTD_compressStream2(cctx, &output, &input, ZDTD_e_end)
>> if (ZSTD_isError(ret)) {
>> ret = -EIO.
>> goto out;
>> }
>> } while (ret || input.pos < input.size);
>>
>>>
>>> This is from my tests:
>>>
>>> (gdb) p ret
>>> $1 = 11
>>> (gdb) p input
>>> $2 = {src = 0x562305536000, size = 65536, pos = 65536}
>>> (gdb) p output
>>> $3 = {dst = 0x562305546000, size = 65535, pos = 65535}
>>>
>>> Alternatively, we can replace the check with something like
>>>
>>> if (ret != 0) {
>>> ret = -ENOMEM;
>>> }
>>
>> It's not correct either, it's not an error: it just means that we need to flush a bit more data.
> .. but we don't have space to do it, so it looks like -ENOMEM
Why don't we have? See example above.
>>
>>>
>>> after the loop, but I think both are equivalent, so I would stick with my one :)))
>>>> work anyway.
>>>>
>>>>> + };
>>>>> +
>>>>> + /* make sure we can safely return compressed buffer size with ssize_t */
>>>>> + assert(output.pos <= SSIZE_MAX);
>>>>
>>>> Hmm. I hope it's not possible for cluster. But taking the function in separate, it _is_ possible.
>>>> So may be better to assert at function start that
>>>>
>>>> assert(dest_size <= SSIZE_MAX);
>>>>
>>>> To stress, that this limitation is part of qcow2_zstd_compress() interface.
>>> Agree, this is better
>>>>
>>>>> + ret = output.pos;
>>>>> +
>>>>> +out:
>>>>> + ZSTD_freeCCtx(cctx);
>>>>> + return ret;
>>>>> +}
>>>>> +
>>>>> +/*
>>>>> + * 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)
>>>>> +{
>>>>> + size_t ret = 0;
>>>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>>>> + ZSTD_DCtx *dctx = ZSTD_createDCtx();
>>>>> +
>>>>> + if (!dctx) {
>>>>> + return -EIO;
>>>>> + }
>>>>> +
>>>>> + /*
>>>>> + * The compressed stream from input buffer may consist from more
>>>>> + * than one zstd frames. So we iterate until we get a fully
>>>>> + * uncompressed cluster.
>>>>> + */
>>>>> + while (output.pos < output.size) {
>>>>> + ret = ZSTD_decompressStream(dctx, &output, &input);
>>>>> + /*
>>>>> + * if we don't fully populate the output but have read
>>>>> + * all the frames from the input, we end up with error
>>>>> + * here
>>>>> + */
>>>>> + if (ZSTD_isError(ret)) {
>>>>> + ret = -EIO;
>>>>> + break;
>>>>> + }
>>>>> + /*
>>>>> + * Dest buffer size is the image cluster size.
>>>>> + * It should be big enough to store uncompressed content.
>>>>> + * There shouldn't be any cases when the decompressed content
>>>>> + * size is greater then the cluster size, except cluster
>>>>> + * damaging.
>>>>> + */
>>>>> + if (output.pos + ret > output.size) {
>>>>> + ret = -EIO;
>>>>> + break;
>>>>> + }
>>>>
>>>> But here, you use
>>>> "
>>>> or any other value > 0, which means there is still some decoding or flushing to do to complete current frame :
>>>> the return value is a suggested next input size (just a hint for better latency)
>>>> that will never request more than the remaining frame size.
>>>> "
>>>>
>>>> I'm afraid that "just a hint" is not safe API to make a conclusion from. So, I'd prefer to drop this optimization
>>>> and just wait for an error from next ZSTD_decompressStream.
>>>>
>>>> And therefore, for symmetry drop similar optimization on compression part..
>>>>
>>>> What do you think?
>>> I'd add some kind of check that we have finished with ret==0 (after loop). It looks like this is the only case when we can be sure that everything went ok.
>>
>> I think, we should not check it. It is possible that compressed data of another cluster is starting below input end. Is it guaranteed that ZSTD_decompressStream will not start to decompress (or at least plan to do it) the next frame, which is unrelated to our cluster? I'm afraid it's not guaranteed, so we can get ret>0 when output.pos=output.size in correct situation. So I think it's safer not to add this final check for ret. Note that we are not protected from wrong data anyway.
> Looking at zlib_compress implementation, yes it seems to be, so.
> Ok, I'll drop the check.
>
>>
>>>>
>>>>
>>>>> + }
>>>>> +
>>>>> + ZSTD_freeDCtx(dctx);
>>>>> + return ret;
>>>>> +}
>>>>> +#endif
>>>>> +
>>>>> static int qcow2_compress_pool_func(void *opaque)
>>>>> {
>>>>> Qcow2CompressData *data = opaque;
>>>>> @@ -217,6 +345,11 @@ 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:
>>>>> abort();
>>>>> }
>>>>> @@ -249,6 +382,11 @@ 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:
>>>>> abort();
>>>>> }
>>>>> diff --git a/block/qcow2.c b/block/qcow2.c
>>>>> index 643698934d..6632daf50b 100644
>>>>> --- a/block/qcow2.c
>>>>> +++ b/block/qcow2.c
>>>>> @@ -1246,6 +1246,9 @@ static int validate_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:
>>>>> @@ -3461,6 +3464,10 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
>>>>> }
>>>>> switch (qcow2_opts->compression_type) {
>>>>> +#ifdef CONFIG_ZSTD
>>>>> + case QCOW2_COMPRESSION_TYPE_ZSTD:
>>>>> + break;
>>>>> +#endif
>>>>> default:
>>>>> error_setg(errp, "Unknown compression type");
>>>>> goto out;
>>>>>
>>>>
>>>>
>>>
>>
>>
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v11 3/4] qcow2: add zstd cluster compression
2020-03-31 8:10 ` Vladimir Sementsov-Ogievskiy
@ 2020-03-31 8:34 ` Denis Plotnikov
2020-03-31 9:02 ` Vladimir Sementsov-Ogievskiy
0 siblings, 1 reply; 12+ messages in thread
From: Denis Plotnikov @ 2020-03-31 8:34 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-devel
Cc: kwolf, berto, qemu-block, armbru, mreitz, den
On 31.03.2020 11:10, Vladimir Sementsov-Ogievskiy wrote:
> 31.03.2020 10:55, Denis Plotnikov wrote:
>>
>>
>> On 31.03.2020 09:22, Vladimir Sementsov-Ogievskiy wrote:
>>> 30.03.2020 18:04, Denis Plotnikov wrote:
>>>>
>>>>
>>>> On 30.03.2020 16:14, Vladimir Sementsov-Ogievskiy wrote:
>>>>> 30.03.2020 12:54, Denis Plotnikov wrote:
>>>>>> zstd significantly reduces cluster compression time.
>>>>>> It provides better compression performance maintaining
>>>>>> the same level of the compression ratio in comparison with
>>>>>> zlib, which, at the moment, is 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>
>>>>>> QAPI part:
>>>>>> Acked-by: Markus Armbruster <armbru@redhat.com>
>>>>>> ---
>>>>>> docs/interop/qcow2.txt | 1 +
>>>>>> configure | 2 +-
>>>>>> qapi/block-core.json | 3 +-
>>>>>> block/qcow2-threads.c | 138
>>>>>> +++++++++++++++++++++++++++++++++++++++++
>>>>>> block/qcow2.c | 7 +++
>>>>>> 5 files changed, 149 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
>>>>>> index 5597e24474..795dbb21dd 100644
>>>>>> --- a/docs/interop/qcow2.txt
>>>>>> +++ b/docs/interop/qcow2.txt
>>>>>> @@ -208,6 +208,7 @@ version 2.
>>>>>> Available compression type values:
>>>>>> 0: zlib <https://www.zlib.net/>
>>>>>> + 1: zstd <http://github.com/facebook/zstd>
>>>>>> === Header padding ===
>>>>>> diff --git a/configure b/configure
>>>>>> index da09c35895..57cac2abe1 100755
>>>>>> --- a/configure
>>>>>> +++ b/configure
>>>>>> @@ -1861,7 +1861,7 @@ disabled with --disable-FEATURE, default is
>>>>>> enabled if available:
>>>>>> lzfse support of lzfse compression library
>>>>>> (for reading lzfse-compressed dmg images)
>>>>>> zstd support for zstd compression library
>>>>>> - (for migration compression)
>>>>>> + (for migration compression and qcow2 cluster
>>>>>> compression)
>>>>>> seccomp seccomp support
>>>>>> coroutine-pool coroutine freelist (better performance)
>>>>>> glusterfs GlusterFS backend
>>>>>> diff --git a/qapi/block-core.json b/qapi/block-core.json
>>>>>> index d669ec0965..44690ed266 100644
>>>>>> --- a/qapi/block-core.json
>>>>>> +++ b/qapi/block-core.json
>>>>>> @@ -4293,11 +4293,12 @@
>>>>>> # Compression type used in qcow2 image file
>>>>>> #
>>>>>> # @zlib: zlib compression, see <http://zlib.net/>
>>>>>> +# @zstd: zstd compression, see <http://github.com/facebook/zstd>
>>>>>> #
>>>>>> # Since: 5.0
>>>>>> ##
>>>>>> { 'enum': 'Qcow2CompressionType',
>>>>>> - 'data': [ 'zlib' ] }
>>>>>> + 'data': [ 'zlib', { 'name': 'zstd', 'if':
>>>>>> 'defined(CONFIG_ZSTD)' } ] }
>>>>>> ##
>>>>>> # @BlockdevCreateOptionsQcow2:
>>>>>> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
>>>>>> index 7dbaf53489..b8ccd97009 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"
>>>>>> @@ -166,6 +171,129 @@ 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)
>>>>>> +{
>>>>>> + size_t ret;
>>>>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>>>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>>>>> + ZSTD_CCtx *cctx = ZSTD_createCCtx();
>>>>>> +
>>>>>> + if (!cctx) {
>>>>>> + return -EIO;
>>>>>> + }
>>>>>> + /*
>>>>>> + * ZSTD spec: "You must continue calling ZSTD_compressStream2()
>>>>>> + * with ZSTD_e_end until it returns 0, at which point you are
>>>>>> + * free to start a new frame".
>>>>>> + * In the loop, we try to compress all the data into one
>>>>>> zstd frame.
>>>>>> + * ZSTD_compressStream2 can potentially finish a frame earlier
>>>>>> + * than the full input data is consumed. That's why we are
>>>>>> looping
>>>>>> + * until all the input data is consumed.
>>>>>> + */
>>>>>> + while (input.pos < input.size) {
>>>>>> + /*
>>>>>> + * zstd simple interface requires the exact compressed
>>>>>> size.
>>>>>
>>>>> on decompression you mean
>>>>>
>>>>>> + * zstd stream interface reads the comressed size from
>>>>>> + * the compressed stream frame.
>>>>>
>>>>> compressed size is not stored in the stream. I think, that streamed
>>>>> interface just decompress until it have something to decompress and
>>>>> have space to write output.
>>>>>
>>>>>> + * Instruct zstd to compress the whole buffer and write
>>>>>> + * the frame which includes the compressed size.
>>>>>
>>>>> I think this is wrong. compression size is not written.
>>>> Ok
>>>>>
>>>>>> + * This allows as to use zstd streaming semantics and
>>>>>> + * don't store the compressed size for the zstd
>>>>>> decompression.
>>>>>> + */
>>>>>
>>>>> Comment is just outdated. Accordingly to our off-list discussion, I'd
>>>>> rewrite it like this:
>>>>>
>>>>> We want to use streamed interface on decompression, as we will not
>>>>> know
>>>>> exact size of compression data.
>>>> This one is better then mine.
>>>>> Use streamed interface for compression
>>>>> just for symmetry.
>>>> I think this one is exceeding. If we have stream family functions
>>>> on both sides this won't rise any questions from the reader.
>>>>
>>>>>
>>>>>
>>>>>> + ret = ZSTD_compressStream2(cctx, &output, &input,
>>>>>> ZSTD_e_end);
>>>>>> + if (ZSTD_isError(ret)) {
>>>>>> + ret = -EIO;
>>>>>> + goto out;
>>>>>> + }
>>>>>> + /* Dest buffer isn't big enough to store compressed
>>>>>> content */
>>>>>> + if (output.pos + ret > output.size) {
>>>>>> + ret = -ENOMEM;
>>>>>> + goto out;
>>>>>> + }
>>>>>
>>>>> Here you use "@return provides a minimum amount of data remaining
>>>>> to be flushed from internal buffers
>>>>> or an error code, which can be tested using
>>>>> ZSTD_isError()."
>>>>>
>>>>> I think we can safely drop this check
>>>> No, we can't.
>>>> we should check for if zstd managed to write the stream correctly.
>>>> ZSTD_compressStream2 may consume all the input buffer but return
>>>> ret > 0 meaning that it needs more space.
>>>
>>> Hmm, interesting thing. But your check doesn't protect us from it:
>>>
>>> Assume we have
>>>
>>> output.size = input.size = 64K
>>> output.pos = 64K
>>> input.pos = 10K
>>> ret = 10K
>>>
>>> - which means that all input is consumed, but we have some cached
>>> data (at least 10K) to flush.
>>>
>>> 10K + 10K = 20K < 64K, so your check will no lead to an error, but
>>> we'll exit the loop..
>> No, it does protect
>> you use incorrect formula: _input_.pos + ret < output.size
>>
>> but the code is
>>
>> if (output.pos + ret > output.size) {
>> ret = -ENOMEM;
>> goto out;
>> }
>>
>> so, 64K + 10K = 74K -> 74K > 64K (true) -> ret = -ENOMEM
>
> Oops, than another example:
>
> output.size = input.size = 64K
> output.pos = 40K
> input.pos = 64K
> ret = 10K
>
> your check doesn't catch it, and it's not an error. But we exit the
> loop (because input.pos == input.size) and don't write last 10K.
The check is supposed to check for no memory cases. Obviously, your
example is NOT no memory case, since 40+10 > 64 -- false.
ret > 0 shouldn't happen, since compres has consumed everything it
could, but who knows, what ZSTD_compressStream2 decided to return.
So, ok, we need to do one more iteration untill ret == 0
like so
do {
ret = ZSTD_compressStream2(cctx, &output, &input, ZDTD_e_end)
if (ZSTD_isError(ret)) {
ret = -EIO.
goto out;
}
if (output.pos + ret > output.size) {
ret = -ENOMEM;
goto out;
}
} while (ret || input.pos < input.size);
I'd like to insist that the no memory check is valid and useful.
>
>
>>
>>>
>>> So, actually, what we need it two things:
>>>
>>> 1. input.pos = input.size, which means that all input is consumed
>>> 2. ret = 0, which means that all cached data flushed
>>>
>>> So we need something like
>>>
>>> do {
>>> ret = ZSTD_compressStream2(cctx, &output, &input, ZDTD_e_end)
>>> if (ZSTD_isError(ret)) {
>>> ret = -EIO.
>>> goto out;
>>> }
>>> } while (ret || input.pos < input.size);
>>>
>>>>
>>>> This is from my tests:
>>>>
>>>> (gdb) p ret
>>>> $1 = 11
>>>> (gdb) p input
>>>> $2 = {src = 0x562305536000, size = 65536, pos = 65536}
>>>> (gdb) p output
>>>> $3 = {dst = 0x562305546000, size = 65535, pos = 65535}
>>>>
>>>> Alternatively, we can replace the check with something like
>>>>
>>>> if (ret != 0) {
>>>> ret = -ENOMEM;
>>>> }
>>>
>>> It's not correct either, it's not an error: it just means that we
>>> need to flush a bit more data.
>> .. but we don't have space to do it, so it looks like -ENOMEM
>
> Why don't we have? See example above.
>
>>>
>>>>
>>>> after the loop, but I think both are equivalent, so I would stick
>>>> with my one :)))
>>>>> work anyway.
>>>>>
>>>>>> + };
>>>>>> +
>>>>>> + /* make sure we can safely return compressed buffer size
>>>>>> with ssize_t */
>>>>>> + assert(output.pos <= SSIZE_MAX);
>>>>>
>>>>> Hmm. I hope it's not possible for cluster. But taking the function
>>>>> in separate, it _is_ possible.
>>>>> So may be better to assert at function start that
>>>>>
>>>>> assert(dest_size <= SSIZE_MAX);
>>>>>
>>>>> To stress, that this limitation is part of qcow2_zstd_compress()
>>>>> interface.
>>>> Agree, this is better
>>>>>
>>>>>> + ret = output.pos;
>>>>>> +
>>>>>> +out:
>>>>>> + ZSTD_freeCCtx(cctx);
>>>>>> + return ret;
>>>>>> +}
>>>>>> +
>>>>>> +/*
>>>>>> + * 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)
>>>>>> +{
>>>>>> + size_t ret = 0;
>>>>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>>>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>>>>> + ZSTD_DCtx *dctx = ZSTD_createDCtx();
>>>>>> +
>>>>>> + if (!dctx) {
>>>>>> + return -EIO;
>>>>>> + }
>>>>>> +
>>>>>> + /*
>>>>>> + * The compressed stream from input buffer may consist from
>>>>>> more
>>>>>> + * than one zstd frames. So we iterate until we get a fully
>>>>>> + * uncompressed cluster.
>>>>>> + */
>>>>>> + while (output.pos < output.size) {
>>>>>> + ret = ZSTD_decompressStream(dctx, &output, &input);
>>>>>> + /*
>>>>>> + * if we don't fully populate the output but have read
>>>>>> + * all the frames from the input, we end up with error
>>>>>> + * here
>>>>>> + */
>>>>>> + if (ZSTD_isError(ret)) {
>>>>>> + ret = -EIO;
>>>>>> + break;
>>>>>> + }
>>>>>> + /*
>>>>>> + * Dest buffer size is the image cluster size.
>>>>>> + * It should be big enough to store uncompressed content.
>>>>>> + * There shouldn't be any cases when the decompressed
>>>>>> content
>>>>>> + * size is greater then the cluster size, except cluster
>>>>>> + * damaging.
>>>>>> + */
>>>>>> + if (output.pos + ret > output.size) {
>>>>>> + ret = -EIO;
>>>>>> + break;
>>>>>> + }
>>>>>
>>>>> But here, you use
>>>>> "
>>>>> or any other value > 0, which means there is still some decoding
>>>>> or flushing to do to complete current frame :
>>>>> the return value is a suggested
>>>>> next input size (just a hint for better latency)
>>>>> that will never request more than
>>>>> the remaining frame size.
>>>>> "
>>>>>
>>>>> I'm afraid that "just a hint" is not safe API to make a conclusion
>>>>> from. So, I'd prefer to drop this optimization
>>>>> and just wait for an error from next ZSTD_decompressStream.
>>>>>
>>>>> And therefore, for symmetry drop similar optimization on
>>>>> compression part..
>>>>>
>>>>> What do you think?
>>>> I'd add some kind of check that we have finished with ret==0 (after
>>>> loop). It looks like this is the only case when we can be sure that
>>>> everything went ok.
>>>
>>> I think, we should not check it. It is possible that compressed data
>>> of another cluster is starting below input end. Is it guaranteed
>>> that ZSTD_decompressStream will not start to decompress (or at least
>>> plan to do it) the next frame, which is unrelated to our cluster?
>>> I'm afraid it's not guaranteed, so we can get ret>0 when
>>> output.pos=output.size in correct situation. So I think it's safer
>>> not to add this final check for ret. Note that we are not protected
>>> from wrong data anyway.
>> Looking at zlib_compress implementation, yes it seems to be, so.
>> Ok, I'll drop the check.
>>
>>>
>>>>>
>>>>>
>>>>>> + }
>>>>>> +
>>>>>> + ZSTD_freeDCtx(dctx);
>>>>>> + return ret;
>>>>>> +}
>>>>>> +#endif
>>>>>> +
>>>>>> static int qcow2_compress_pool_func(void *opaque)
>>>>>> {
>>>>>> Qcow2CompressData *data = opaque;
>>>>>> @@ -217,6 +345,11 @@ 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:
>>>>>> abort();
>>>>>> }
>>>>>> @@ -249,6 +382,11 @@ 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:
>>>>>> abort();
>>>>>> }
>>>>>> diff --git a/block/qcow2.c b/block/qcow2.c
>>>>>> index 643698934d..6632daf50b 100644
>>>>>> --- a/block/qcow2.c
>>>>>> +++ b/block/qcow2.c
>>>>>> @@ -1246,6 +1246,9 @@ static int
>>>>>> validate_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:
>>>>>> @@ -3461,6 +3464,10 @@ qcow2_co_create(BlockdevCreateOptions
>>>>>> *create_options, Error **errp)
>>>>>> }
>>>>>> switch (qcow2_opts->compression_type) {
>>>>>> +#ifdef CONFIG_ZSTD
>>>>>> + case QCOW2_COMPRESSION_TYPE_ZSTD:
>>>>>> + break;
>>>>>> +#endif
>>>>>> default:
>>>>>> error_setg(errp, "Unknown compression type");
>>>>>> goto out;
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
>
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v11 3/4] qcow2: add zstd cluster compression
2020-03-31 8:34 ` Denis Plotnikov
@ 2020-03-31 9:02 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 12+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-03-31 9:02 UTC (permalink / raw)
To: Denis Plotnikov, qemu-devel; +Cc: kwolf, berto, qemu-block, armbru, mreitz, den
31.03.2020 11:34, Denis Plotnikov wrote:
>
>
> On 31.03.2020 11:10, Vladimir Sementsov-Ogievskiy wrote:
>> 31.03.2020 10:55, Denis Plotnikov wrote:
>>>
>>>
>>> On 31.03.2020 09:22, Vladimir Sementsov-Ogievskiy wrote:
>>>> 30.03.2020 18:04, Denis Plotnikov wrote:
>>>>>
>>>>>
>>>>> On 30.03.2020 16:14, Vladimir Sementsov-Ogievskiy wrote:
>>>>>> 30.03.2020 12:54, Denis Plotnikov wrote:
>>>>>>> zstd significantly reduces cluster compression time.
>>>>>>> It provides better compression performance maintaining
>>>>>>> the same level of the compression ratio in comparison with
>>>>>>> zlib, which, at the moment, is 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>
>>>>>>> QAPI part:
>>>>>>> Acked-by: Markus Armbruster <armbru@redhat.com>
>>>>>>> ---
>>>>>>> docs/interop/qcow2.txt | 1 +
>>>>>>> configure | 2 +-
>>>>>>> qapi/block-core.json | 3 +-
>>>>>>> block/qcow2-threads.c | 138 +++++++++++++++++++++++++++++++++++++++++
>>>>>>> block/qcow2.c | 7 +++
>>>>>>> 5 files changed, 149 insertions(+), 2 deletions(-)
>>>>>>>
>>>>>>> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
>>>>>>> index 5597e24474..795dbb21dd 100644
>>>>>>> --- a/docs/interop/qcow2.txt
>>>>>>> +++ b/docs/interop/qcow2.txt
>>>>>>> @@ -208,6 +208,7 @@ version 2.
>>>>>>> Available compression type values:
>>>>>>> 0: zlib <https://www.zlib.net/>
>>>>>>> + 1: zstd <http://github.com/facebook/zstd>
>>>>>>> === Header padding ===
>>>>>>> diff --git a/configure b/configure
>>>>>>> index da09c35895..57cac2abe1 100755
>>>>>>> --- a/configure
>>>>>>> +++ b/configure
>>>>>>> @@ -1861,7 +1861,7 @@ disabled with --disable-FEATURE, default is enabled if available:
>>>>>>> lzfse support of lzfse compression library
>>>>>>> (for reading lzfse-compressed dmg images)
>>>>>>> zstd support for zstd compression library
>>>>>>> - (for migration compression)
>>>>>>> + (for migration compression and qcow2 cluster compression)
>>>>>>> seccomp seccomp support
>>>>>>> coroutine-pool coroutine freelist (better performance)
>>>>>>> glusterfs GlusterFS backend
>>>>>>> diff --git a/qapi/block-core.json b/qapi/block-core.json
>>>>>>> index d669ec0965..44690ed266 100644
>>>>>>> --- a/qapi/block-core.json
>>>>>>> +++ b/qapi/block-core.json
>>>>>>> @@ -4293,11 +4293,12 @@
>>>>>>> # Compression type used in qcow2 image file
>>>>>>> #
>>>>>>> # @zlib: zlib compression, see <http://zlib.net/>
>>>>>>> +# @zstd: zstd compression, see <http://github.com/facebook/zstd>
>>>>>>> #
>>>>>>> # Since: 5.0
>>>>>>> ##
>>>>>>> { 'enum': 'Qcow2CompressionType',
>>>>>>> - 'data': [ 'zlib' ] }
>>>>>>> + 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] }
>>>>>>> ##
>>>>>>> # @BlockdevCreateOptionsQcow2:
>>>>>>> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
>>>>>>> index 7dbaf53489..b8ccd97009 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"
>>>>>>> @@ -166,6 +171,129 @@ 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)
>>>>>>> +{
>>>>>>> + size_t ret;
>>>>>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>>>>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>>>>>> + ZSTD_CCtx *cctx = ZSTD_createCCtx();
>>>>>>> +
>>>>>>> + if (!cctx) {
>>>>>>> + return -EIO;
>>>>>>> + }
>>>>>>> + /*
>>>>>>> + * ZSTD spec: "You must continue calling ZSTD_compressStream2()
>>>>>>> + * with ZSTD_e_end until it returns 0, at which point you are
>>>>>>> + * free to start a new frame".
>>>>>>> + * In the loop, we try to compress all the data into one zstd frame.
>>>>>>> + * ZSTD_compressStream2 can potentially finish a frame earlier
>>>>>>> + * than the full input data is consumed. That's why we are looping
>>>>>>> + * until all the input data is consumed.
>>>>>>> + */
>>>>>>> + while (input.pos < input.size) {
>>>>>>> + /*
>>>>>>> + * zstd simple interface requires the exact compressed size.
>>>>>>
>>>>>> on decompression you mean
>>>>>>
>>>>>>> + * zstd stream interface reads the comressed size from
>>>>>>> + * the compressed stream frame.
>>>>>>
>>>>>> compressed size is not stored in the stream. I think, that streamed
>>>>>> interface just decompress until it have something to decompress and
>>>>>> have space to write output.
>>>>>>
>>>>>>> + * Instruct zstd to compress the whole buffer and write
>>>>>>> + * the frame which includes the compressed size.
>>>>>>
>>>>>> I think this is wrong. compression size is not written.
>>>>> Ok
>>>>>>
>>>>>>> + * This allows as to use zstd streaming semantics and
>>>>>>> + * don't store the compressed size for the zstd decompression.
>>>>>>> + */
>>>>>>
>>>>>> Comment is just outdated. Accordingly to our off-list discussion, I'd
>>>>>> rewrite it like this:
>>>>>>
>>>>>> We want to use streamed interface on decompression, as we will not know
>>>>>> exact size of compression data.
>>>>> This one is better then mine.
>>>>>> Use streamed interface for compression
>>>>>> just for symmetry.
>>>>> I think this one is exceeding. If we have stream family functions on both sides this won't rise any questions from the reader.
>>>>>
>>>>>>
>>>>>>
>>>>>>> + ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);
>>>>>>> + if (ZSTD_isError(ret)) {
>>>>>>> + ret = -EIO;
>>>>>>> + goto out;
>>>>>>> + }
>>>>>>> + /* Dest buffer isn't big enough to store compressed content */
>>>>>>> + if (output.pos + ret > output.size) {
>>>>>>> + ret = -ENOMEM;
>>>>>>> + goto out;
>>>>>>> + }
>>>>>>
>>>>>> Here you use "@return provides a minimum amount of data remaining to be flushed from internal buffers
>>>>>> or an error code, which can be tested using ZSTD_isError()."
>>>>>>
>>>>>> I think we can safely drop this check
>>>>> No, we can't.
>>>>> we should check for if zstd managed to write the stream correctly. ZSTD_compressStream2 may consume all the input buffer but return ret > 0 meaning that it needs more space.
>>>>
>>>> Hmm, interesting thing. But your check doesn't protect us from it:
>>>>
>>>> Assume we have
>>>>
>>>> output.size = input.size = 64K
>>>> output.pos = 64K
>>>> input.pos = 10K
>>>> ret = 10K
>>>>
>>>> - which means that all input is consumed, but we have some cached data (at least 10K) to flush.
>>>>
>>>> 10K + 10K = 20K < 64K, so your check will no lead to an error, but we'll exit the loop..
>>> No, it does protect
>>> you use incorrect formula: _input_.pos + ret < output.size
>>>
>>> but the code is
>>>
>>> if (output.pos + ret > output.size) {
>>> ret = -ENOMEM;
>>> goto out;
>>> }
>>>
>>> so, 64K + 10K = 74K -> 74K > 64K (true) -> ret = -ENOMEM
>>
>> Oops, than another example:
>>
>> output.size = input.size = 64K
>> output.pos = 40K
>> input.pos = 64K
>> ret = 10K
>>
>> your check doesn't catch it, and it's not an error. But we exit the loop (because input.pos == input.size) and don't write last 10K.
> The check is supposed to check for no memory cases. Obviously, your example is NOT no memory case, since 40+10 > 64 -- false.
>
> ret > 0 shouldn't happen, since compres has consumed everything it could, but who knows, what ZSTD_compressStream2 decided to return.
>
> So, ok, we need to do one more iteration untill ret == 0
>
> like so
>
> do {
> ret = ZSTD_compressStream2(cctx, &output, &input, ZDTD_e_end)
> if (ZSTD_isError(ret)) {
> ret = -EIO.
> goto out;
> }
> if (output.pos + ret > output.size) {
> ret = -ENOMEM;
> goto out;
> }
>
> } while (ret || input.pos < input.size);
>
> I'd like to insist that the no memory check is valid and useful.
Agree, I understand now: we may go to infinite loop, where ZSTD will ask for more space.
>
>
>>
>>
>>>
>>>>
>>>> So, actually, what we need it two things:
>>>>
>>>> 1. input.pos = input.size, which means that all input is consumed
>>>> 2. ret = 0, which means that all cached data flushed
>>>>
>>>> So we need something like
>>>>
>>>> do {
>>>> ret = ZSTD_compressStream2(cctx, &output, &input, ZDTD_e_end)
>>>> if (ZSTD_isError(ret)) {
>>>> ret = -EIO.
>>>> goto out;
>>>> }
>>>> } while (ret || input.pos < input.size);
>>>>
>>>>>
>>>>> This is from my tests:
>>>>>
>>>>> (gdb) p ret
>>>>> $1 = 11
>>>>> (gdb) p input
>>>>> $2 = {src = 0x562305536000, size = 65536, pos = 65536}
>>>>> (gdb) p output
>>>>> $3 = {dst = 0x562305546000, size = 65535, pos = 65535}
>>>>>
>>>>> Alternatively, we can replace the check with something like
>>>>>
>>>>> if (ret != 0) {
>>>>> ret = -ENOMEM;
>>>>> }
>>>>
>>>> It's not correct either, it's not an error: it just means that we need to flush a bit more data.
>>> .. but we don't have space to do it, so it looks like -ENOMEM
>>
>> Why don't we have? See example above.
>>
>>>>
>>>>>
>>>>> after the loop, but I think both are equivalent, so I would stick with my one :)))
>>>>>> work anyway.
>>>>>>
>>>>>>> + };
>>>>>>> +
>>>>>>> + /* make sure we can safely return compressed buffer size with ssize_t */
>>>>>>> + assert(output.pos <= SSIZE_MAX);
>>>>>>
>>>>>> Hmm. I hope it's not possible for cluster. But taking the function in separate, it _is_ possible.
>>>>>> So may be better to assert at function start that
>>>>>>
>>>>>> assert(dest_size <= SSIZE_MAX);
>>>>>>
>>>>>> To stress, that this limitation is part of qcow2_zstd_compress() interface.
>>>>> Agree, this is better
>>>>>>
>>>>>>> + ret = output.pos;
>>>>>>> +
>>>>>>> +out:
>>>>>>> + ZSTD_freeCCtx(cctx);
>>>>>>> + return ret;
>>>>>>> +}
>>>>>>> +
>>>>>>> +/*
>>>>>>> + * 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)
>>>>>>> +{
>>>>>>> + size_t ret = 0;
>>>>>>> + ZSTD_outBuffer output = { dest, dest_size, 0 };
>>>>>>> + ZSTD_inBuffer input = { src, src_size, 0 };
>>>>>>> + ZSTD_DCtx *dctx = ZSTD_createDCtx();
>>>>>>> +
>>>>>>> + if (!dctx) {
>>>>>>> + return -EIO;
>>>>>>> + }
>>>>>>> +
>>>>>>> + /*
>>>>>>> + * The compressed stream from input buffer may consist from more
>>>>>>> + * than one zstd frames. So we iterate until we get a fully
>>>>>>> + * uncompressed cluster.
>>>>>>> + */
>>>>>>> + while (output.pos < output.size) {
>>>>>>> + ret = ZSTD_decompressStream(dctx, &output, &input);
>>>>>>> + /*
>>>>>>> + * if we don't fully populate the output but have read
>>>>>>> + * all the frames from the input, we end up with error
>>>>>>> + * here
>>>>>>> + */
>>>>>>> + if (ZSTD_isError(ret)) {
>>>>>>> + ret = -EIO;
>>>>>>> + break;
>>>>>>> + }
>>>>>>> + /*
>>>>>>> + * Dest buffer size is the image cluster size.
>>>>>>> + * It should be big enough to store uncompressed content.
>>>>>>> + * There shouldn't be any cases when the decompressed content
>>>>>>> + * size is greater then the cluster size, except cluster
>>>>>>> + * damaging.
>>>>>>> + */
>>>>>>> + if (output.pos + ret > output.size) {
>>>>>>> + ret = -EIO;
>>>>>>> + break;
>>>>>>> + }
>>>>>>
>>>>>> But here, you use
>>>>>> "
>>>>>> or any other value > 0, which means there is still some decoding or flushing to do to complete current frame :
>>>>>> the return value is a suggested next input size (just a hint for better latency)
>>>>>> that will never request more than the remaining frame size.
>>>>>> "
>>>>>>
>>>>>> I'm afraid that "just a hint" is not safe API to make a conclusion from. So, I'd prefer to drop this optimization
>>>>>> and just wait for an error from next ZSTD_decompressStream.
>>>>>>
>>>>>> And therefore, for symmetry drop similar optimization on compression part..
>>>>>>
>>>>>> What do you think?
>>>>> I'd add some kind of check that we have finished with ret==0 (after loop). It looks like this is the only case when we can be sure that everything went ok.
>>>>
>>>> I think, we should not check it. It is possible that compressed data of another cluster is starting below input end. Is it guaranteed that ZSTD_decompressStream will not start to decompress (or at least plan to do it) the next frame, which is unrelated to our cluster? I'm afraid it's not guaranteed, so we can get ret>0 when output.pos=output.size in correct situation. So I think it's safer not to add this final check for ret. Note that we are not protected from wrong data anyway.
>>> Looking at zlib_compress implementation, yes it seems to be, so.
>>> Ok, I'll drop the check.
>>>
>>>>
>>>>>>
>>>>>>
>>>>>>> + }
>>>>>>> +
>>>>>>> + ZSTD_freeDCtx(dctx);
>>>>>>> + return ret;
>>>>>>> +}
>>>>>>> +#endif
>>>>>>> +
>>>>>>> static int qcow2_compress_pool_func(void *opaque)
>>>>>>> {
>>>>>>> Qcow2CompressData *data = opaque;
>>>>>>> @@ -217,6 +345,11 @@ 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:
>>>>>>> abort();
>>>>>>> }
>>>>>>> @@ -249,6 +382,11 @@ 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:
>>>>>>> abort();
>>>>>>> }
>>>>>>> diff --git a/block/qcow2.c b/block/qcow2.c
>>>>>>> index 643698934d..6632daf50b 100644
>>>>>>> --- a/block/qcow2.c
>>>>>>> +++ b/block/qcow2.c
>>>>>>> @@ -1246,6 +1246,9 @@ static int validate_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:
>>>>>>> @@ -3461,6 +3464,10 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
>>>>>>> }
>>>>>>> switch (qcow2_opts->compression_type) {
>>>>>>> +#ifdef CONFIG_ZSTD
>>>>>>> + case QCOW2_COMPRESSION_TYPE_ZSTD:
>>>>>>> + break;
>>>>>>> +#endif
>>>>>>> default:
>>>>>>> error_setg(errp, "Unknown compression type");
>>>>>>> goto out;
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>>
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2020-03-31 9:04 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-30 9:54 [PATCH v11 0/4] qcow2: Implement zstd cluster compression method Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 1/4] qcow2: introduce compression type feature Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 2/4] qcow2: rework the cluster compression routine Denis Plotnikov
2020-03-30 9:54 ` [PATCH v11 3/4] qcow2: add zstd cluster compression Denis Plotnikov
2020-03-30 13:14 ` Vladimir Sementsov-Ogievskiy
2020-03-30 15:04 ` Denis Plotnikov
2020-03-31 6:22 ` Vladimir Sementsov-Ogievskiy
2020-03-31 7:55 ` Denis Plotnikov
2020-03-31 8:10 ` Vladimir Sementsov-Ogievskiy
2020-03-31 8:34 ` Denis Plotnikov
2020-03-31 9:02 ` Vladimir Sementsov-Ogievskiy
2020-03-30 9:54 ` [PATCH v11 4/4] iotests: 287: add qcow2 compression type test Denis Plotnikov
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