This introduces the ability to set the discard granularity option
for a disk. It defines the smallest amount of data that can be
discarded in a single operation (useful for managing and
optimizing storage).
However, most hypervisors automatically set the proper discard
granularity and users usually do not need to change the default
setting.
Signed-off-by: Kristina Hanicova <khanicov@xxxxxxxxxx>
---
docs/formatdomain.rst | 6 +++++-
src/conf/domain_conf.c | 19 ++++++++++++++++++-
src/conf/domain_conf.h | 1 +
src/conf/domain_validate.c | 3 ++-
src/conf/schemas/domaincommon.rng | 5 +++++
src/qemu/qemu_domain.c | 2 ++
src/vz/vz_utils.c | 3 ++-
7 files changed, 35 insertions(+), 4 deletions(-)
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index cd9cb02bf8..0d0812f08c 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -2588,7 +2588,7 @@ paravirtualized driver is specified via the ``disk`` element.
<driver name='qemu' type='raw'/>
<source dev='/dev/sda'/>
<geometry cyls='16383' heads='16' secs='63' trans='lba'/>
- <blockio logical_block_size='512' physical_block_size='4096'/>
+ <blockio logical_block_size='512' physical_block_size='4096' discard_granularity='4096'/>
<target dev='hdj' bus='ide'/>
</disk>
<disk type='volume' device='disk'>
@@ -3435,6 +3435,10 @@ paravirtualized driver is specified via the ``disk`` element.
this would be the value returned by the BLKPBSZGET ioctl and describes the
disk's hardware sector size which can be relevant for the alignment of
disk data.
+ ``discard_granularity``
+ The smallest amount of data that can be discarded in a single operation.
+ It impacts the unmap operations and it must be a multiple of a
+ ``logical_block_size``.
Filesystems
~~~~~~~~~~~
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 69934026ef..bb4f1fdb94 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -8073,6 +8073,10 @@ virDomainDiskDefParseXML(virDomainXMLOption *xmlopt,
if (virXMLPropUInt(blockioNode, "physical_block_size", 10, VIR_XML_PROP_NONE,
&def->blockio.physical_block_size) < 0)
return NULL;
+
+ if (virXMLPropUInt(blockioNode, "discard_granularity", 10, VIR_XML_PROP_NONE,
+ &def->blockio.discard_granularity) < 0)
+ return NULL;
}
if ((driverNode = virXPathNode("./driver", ctxt))) {
@@ -19836,6 +19840,13 @@ virDomainDiskBlockIoCheckABIStability(virDomainDiskDef *src,
dst->blockio.physical_block_size, src->blockio.physical_block_size);
return false;
}
+
+ if (src->blockio.discard_granularity != dst->blockio.discard_granularity) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("Target disk discard_granularity %1$u does not match source %2$u"),
+ dst->blockio.discard_granularity, src->blockio.discard_granularity);
+ return false;
+ }
return true;
}
@@ -22132,7 +22143,8 @@ virDomainDiskBlockIoDefFormat(virBuffer *buf,
virDomainDiskDef *def)
{
if (def->blockio.logical_block_size > 0 ||
- def->blockio.physical_block_size > 0) {
+ def->blockio.physical_block_size > 0 ||
+ def->blockio.discard_granularity > 0) {
virBufferAddLit(buf, "<blockio");
if (def->blockio.logical_block_size > 0) {
virBufferAsprintf(buf,
@@ -22144,6 +22156,11 @@ virDomainDiskBlockIoDefFormat(virBuffer *buf,
" physical_block_size='%u'",
def->blockio.physical_block_size);
}
+ if (def->blockio.discard_granularity > 0) {
+ virBufferAsprintf(buf,
+ " discard_granularity='%u'",
+ def->blockio.discard_granularity);
+ }
virBufferAddLit(buf, "/>\n");
}
}
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 8bef097542..ca195a52d2 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -579,6 +579,7 @@ struct _virDomainDiskDef {
struct {
unsigned int logical_block_size;
unsigned int physical_block_size;
+ unsigned int discard_granularity;
} blockio;
virDomainBlockIoTuneInfo blkdeviotune;
diff --git a/src/conf/domain_validate.c b/src/conf/domain_validate.c
index b286990b19..fd3eed3230 100644
--- a/src/conf/domain_validate.c
+++ b/src/conf/domain_validate.c
@@ -466,7 +466,8 @@ virDomainDiskVhostUserValidate(const virDomainDiskDef *disk)
}
if (disk->blockio.logical_block_size > 0 ||
- disk->blockio.physical_block_size > 0) {
+ disk->blockio.physical_block_size > 0 ||
+ disk->blockio.discard_granularity > 0) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("blockio is not supported with vhostuser disk"));
return -1;
diff --git a/src/conf/schemas/domaincommon.rng b/src/conf/schemas/domaincommon.rng
index 2556ac01ed..de3bd1c35c 100644
--- a/src/conf/schemas/domaincommon.rng
+++ b/src/conf/schemas/domaincommon.rng
@@ -2461,6 +2461,11 @@
<data type="integer"/>
</attribute>
</optional>
+ <optional>
+ <attribute name="discard_granularity">
+ <data type="integer"/>
+ </attribute>
+ </optional>
</element>
</define>
<!--
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 0b2b22a219..bfeddc7746 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -8426,6 +8426,8 @@ qemuDomainDiskChangeSupported(virDomainDiskDef *disk,
"blockio logical_block_size", false);
CHECK_EQ(blockio.physical_block_size,
"blockio physical_block_size", false);
+ CHECK_EQ(blockio.discard_granularity,
+ "blockio discard_granularity", false);
CHECK_EQ(blkdeviotune.total_bytes_sec,
"blkdeviotune total_bytes_sec",
diff --git a/src/vz/vz_utils.c b/src/vz/vz_utils.c
index 7db7dbd419..de707df883 100644
--- a/src/vz/vz_utils.c
+++ b/src/vz/vz_utils.c
@@ -279,7 +279,8 @@ vzCheckDiskUnsupportedParams(virDomainDiskDef *disk)
}
if (disk->blockio.logical_block_size ||
- disk->blockio.physical_block_size) {
+ disk->blockio.physical_block_size ||
+ disk->blockio.discard_granularity) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("Setting disk block sizes is not "
"supported by vz driver."));
--
2.41.0
