7:46 p.m.
This option allows or disallows detection of zero-writes if it is set to
"on" or "off", respectively. It can be also set to "unmap"
in which
case it will try discarding that part of image based on the value of the
"discard" option.
Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com>
---
docs/formatdomain.html.in | 11 ++++++
docs/schemas/domaincommon.rng | 12 ++++++
src/conf/domain_conf.c | 19 ++++++++-
src/conf/domain_conf.h | 11 ++++++
src/libvirt_private.syms | 2 +
.../qemuxml2argv-disk-drive-detect-zeroes.xml | 45 ++++++++++++++++++++++
.../qemuxml2xmlout-disk-drive-detect-zeroes.xml | 1 +
tests/qemuxml2xmltest.c | 1 +
8 files changed, 101 insertions(+), 1 deletion(-)
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-detect-zeroes.xml
create mode 120000 tests/qemuxml2xmloutdata/qemuxml2xmlout-disk-drive-detect-zeroes.xml
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index e737e39d384f..199900963938 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -2574,6 +2574,17 @@
<code>bus</code> and "pci" or "ccw"
<code>address</code> types.
<span class='since'>Since 1.2.8 (QEMU 2.1)</span>
</li>
+ <li>
+ The optional <code>detect_zeroes</code> attribute controls
whether
+ to detect zero write requests. The value can be "off",
"on" or
+ "unmap". First two values turn the detection off and on,
+ respectively. Detecting such writes can take some time, however it
+ can save space for spare images, the third value ("unmap") turns
the
+ detection on and additionally tries to discard such areas from the
+ image based on the value of <code>discard</code> above (it will
act
+ as "on" if <code>discard</code> is set to
"ignore").
+ <span class='since'>Since 1.3.6</span>
+ </li>
</ul>
</dd>
<dt><code>backenddomain</code></dt>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index d14c1c5ecffd..da8de14a8afd 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -1618,6 +1618,9 @@
<optional>
<ref name="driverIOThread"/>
</optional>
+ <optional>
+ <ref name="detect_zeroes"/>
+ </optional>
<empty/>
</element>
</define>
@@ -1702,6 +1705,15 @@
<ref name="unsignedInt"/>
</attribute>
</define>
+ <define name="detect_zeroes">
+ <attribute name='detect_zeroes'>
+ <choice>
+ <value>off</value>
+ <value>on</value>
+ <value>unmap</value>
+ </choice>
+ </attribute>
+ </define>
<define name="controller">
<element name="controller">
<optional>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 9f9fdf24190e..dbff1cfa0399 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -806,6 +806,12 @@ VIR_ENUM_IMPL(virDomainDiskDiscard, VIR_DOMAIN_DISK_DISCARD_LAST,
"unmap",
"ignore")
+VIR_ENUM_IMPL(virDomainDiskDetectZeroes, VIR_DOMAIN_DISK_DETECT_ZEROES_LAST,
+ "default",
+ "off",
+ "on",
+ "unmap")
+
VIR_ENUM_IMPL(virDomainDiskMirrorState, VIR_DOMAIN_DISK_MIRROR_STATE_LAST,
"none",
"yes",
@@ -7203,6 +7209,14 @@ virDomainDiskDefDriverParseXML(virDomainDiskDefPtr def,
VIR_FREE(tmp);
}
+ if ((tmp = virXMLPropString(cur, "detect_zeroes")) &&
+ (def->detect_zeroes = virDomainDiskDetectZeroesTypeFromString(tmp)) <= 0)
{
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("unknown driver detect_zeroes value '%s'"),
tmp);
+ goto cleanup;
+ }
+ VIR_FREE(tmp);
+
ret = 0;
cleanup:
@@ -19368,6 +19382,7 @@ virDomainDiskDefFormat(virBufferPtr buf,
const char *copy_on_read = virTristateSwitchTypeToString(def->copy_on_read);
const char *sgio = virDomainDeviceSGIOTypeToString(def->sgio);
const char *discard = virDomainDiskDiscardTypeToString(def->discard);
+ const char *detect_zeroes =
virDomainDiskDetectZeroesTypeToString(def->detect_zeroes);
if (!type || !def->src->type) {
virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -19422,7 +19437,7 @@ virDomainDiskDefFormat(virBufferPtr buf,
if (def->src->driverName || def->src->format > 0 || def->cachemode
||
def->error_policy || def->rerror_policy || def->iomode ||
def->ioeventfd || def->event_idx || def->copy_on_read ||
- def->discard || def->iothread) {
+ def->discard || def->iothread || def->detect_zeroes) {
virBufferAddLit(buf, "<driver");
virBufferEscapeString(buf, " name='%s'",
def->src->driverName);
if (def->src->format > 0)
@@ -19446,6 +19461,8 @@ virDomainDiskDefFormat(virBufferPtr buf,
virBufferAsprintf(buf, " discard='%s'", discard);
if (def->iothread)
virBufferAsprintf(buf, " iothread='%u'",
def->iothread);
+ if (def->detect_zeroes)
+ virBufferAsprintf(buf, " detect_zeroes='%s'",
detect_zeroes);
virBufferAddLit(buf, "/>\n");
}
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index b1953b31431a..f44daa0b6b2e 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -527,6 +527,15 @@ typedef enum {
VIR_DOMAIN_DISK_DISCARD_LAST
} virDomainDiskDiscard;
+typedef enum {
+ VIR_DOMAIN_DISK_DETECT_ZEROES_DEFAULT = 0,
+ VIR_DOMAIN_DISK_DETECT_ZEROES_OFF,
+ VIR_DOMAIN_DISK_DETECT_ZEROES_ON,
+ VIR_DOMAIN_DISK_DETECT_ZEROES_UNMAP,
+
+ VIR_DOMAIN_DISK_DETECT_ZEROES_LAST
+} virDomainDiskDetectZeroes;
+
typedef struct _virDomainBlockIoTuneInfo virDomainBlockIoTuneInfo;
struct _virDomainBlockIoTuneInfo {
unsigned long long total_bytes_sec;
@@ -605,6 +614,7 @@ struct _virDomainDiskDef {
int sgio; /* enum virDomainDeviceSGIO */
int discard; /* enum virDomainDiskDiscard */
unsigned int iothread; /* unused = 0, > 0 specific thread # */
+ int detect_zeroes; /* enum virDomainDiskDetectZeroes */
char *domain_name; /* backend domain name */
};
@@ -2910,6 +2920,7 @@ VIR_ENUM_DECL(virDomainDiskIo)
VIR_ENUM_DECL(virDomainDeviceSGIO)
VIR_ENUM_DECL(virDomainDiskTray)
VIR_ENUM_DECL(virDomainDiskDiscard)
+VIR_ENUM_DECL(virDomainDiskDetectZeroes)
VIR_ENUM_DECL(virDomainDiskMirrorState)
VIR_ENUM_DECL(virDomainController)
VIR_ENUM_DECL(virDomainControllerModelPCI)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 333bf7c8b2db..b07e90bf9fec 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -266,6 +266,8 @@ virDomainDiskDefForeachPath;
virDomainDiskDefFree;
virDomainDiskDefNew;
virDomainDiskDefSourceParse;
+virDomainDiskDetectZeroesTypeFromString;
+virDomainDiskDetectZeroesTypeToString;
virDomainDiskDeviceTypeToString;
virDomainDiskDiscardTypeToString;
virDomainDiskErrorPolicyTypeFromString;
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-detect-zeroes.xml
b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-detect-zeroes.xml
new file mode 100644
index 000000000000..8953f50f3f92
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-detect-zeroes.xml
@@ -0,0 +1,45 @@
+<domain type='qemu'>
+ <name>test</name>
+ <uuid>92d7a226-cfae-425b-a6d3-00bbf9ec5c9e</uuid>
+ <memory unit='KiB'>1048576</memory>
+ <currentMemory unit='KiB'>1048576</currentMemory>
+ <vcpu placement='static'>1</vcpu>
+ <os>
+ <type arch='x86_64' machine='pc-0.13'>hvm</type>
+ <boot dev='cdrom'/>
+ <boot dev='hd'/>
+ <bootmenu enable='yes'/>
+ </os>
+ <clock offset='utc'/>
+ <on_poweroff>destroy</on_poweroff>
+ <on_reboot>restart</on_reboot>
+ <on_crash>restart</on_crash>
+ <devices>
+ <emulator>/usr/bin/qemu</emulator>
+ <disk type='file' device='disk'>
+ <driver name='qemu' type='qcow2' discard='unmap'
detect_zeroes='unmap'/>
+ <source file='/var/lib/libvirt/images/f14.img'/>
+ <target dev='vda' bus='virtio'/>
+ <address type='pci' domain='0x0000' bus='0x00'
slot='0x04' function='0x0'/>
+ </disk>
+ <disk type='file' device='cdrom'>
+ <driver discard='ignore' detect_zeroes='off'/>
+ <source file='/var/lib/libvirt/Fedora-14-x86_64-Live-KDE.iso'/>
+ <target dev='hdc' bus='ide'/>
+ <readonly/>
+ <address type='drive' controller='0' bus='1'
target='0' unit='0'/>
+ </disk>
+ <controller type='usb' index='0'>
+ <address type='pci' domain='0x0000' bus='0x00'
slot='0x01' function='0x2'/>
+ </controller>
+ <controller type='ide' index='0'>
+ <address type='pci' domain='0x0000' bus='0x00'
slot='0x01' function='0x1'/>
+ </controller>
+ <controller type='pci' index='0' model='pci-root'/>
+ <input type='mouse' bus='ps2'/>
+ <input type='keyboard' bus='ps2'/>
+ <memballoon model='virtio'>
+ <address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/>
+ </memballoon>
+ </devices>
+</domain>
diff --git a/tests/qemuxml2xmloutdata/qemuxml2xmlout-disk-drive-detect-zeroes.xml
b/tests/qemuxml2xmloutdata/qemuxml2xmlout-disk-drive-detect-zeroes.xml
new file mode 120000
index 000000000000..afa3199d4a7e
--- /dev/null
+++ b/tests/qemuxml2xmloutdata/qemuxml2xmlout-disk-drive-detect-zeroes.xml
@@ -0,0 +1 @@
+../qemuxml2argvdata/qemuxml2argv-disk-drive-detect-zeroes.xml
\ No newline at end of file
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index e9d1f938360d..d8810f791f27 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -558,6 +558,7 @@ mymain(void)
DO_TEST("disk-source-pool-mode");
DO_TEST("disk-drive-discard");
+ DO_TEST("disk-drive-detect-zeroes");
DO_TEST("virtio-rng-random");
DO_TEST("virtio-rng-egd");
--
2.8.3