[libvirt] [libvirt PATCH] qemu: Support discard for disk
Osier Yang
jyang at redhat.com
Tue May 14 12:44:54 UTC 2013
QEMU introduced "discard" option for drive since commit a9384aff53,
<...>
@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and
controls whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap})
requests are ignored or passed to the filesystem. Some machine types
may not support discard requests.
</...>
This patch exposes the support in libvirt.
QEMU supported "discard" for "-drive" since v1.5.0-rc0:
% git tag --contains a9384aff53
contains
v1.5.0-rc0
v1.5.0-rc1
So this only detects the capability bit using virQEMUCapsProbeQMPCommandLine.
---
This is on top of https://www.redhat.com/archives/libvir-list/2013-May/msg00979.html
---
docs/formatdomain.html.in | 8 +++++
docs/schemas/domaincommon.rng | 11 +++++++
src/conf/domain_conf.c | 18 +++++++++++
src/conf/domain_conf.h | 10 ++++++
src/libvirt_private.syms | 1 +
src/qemu/qemu_capabilities.c | 2 ++
src/qemu/qemu_capabilities.h | 1 +
src/qemu/qemu_command.c | 11 +++++++
.../qemuxml2argv-disk-drive-discard.args | 8 +++++
.../qemuxml2argv-disk-drive-discard.xml | 37 ++++++++++++++++++++++
tests/qemuxml2argvtest.c | 3 ++
tests/qemuxml2xmltest.c | 2 ++
12 files changed, 112 insertions(+)
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-discard.args
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-discard.xml
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 9ade507..a73d72e 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -1681,6 +1681,14 @@
network. By default copy-on-read is off.
<span class='since'>Since 0.9.10 (QEMU and KVM only)</span>
</li>
+ <li>
+ The optional <code>discard</code> attribute controls whether
+ to discard (also known as "trim" or "unmap") requests are
+ ignored or passed to the filesystem. The value can be either
+ "on" (allow the discard request to be passed) or "off" (ingore
+ the discard request).
+ <span class='since'>Since 1.0.6 (QEMU and KVM only)</span>
+ </li>
</ul>
</dd>
<dt><code>boot</code></dt>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 8004428..2083e95 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -1304,6 +1304,9 @@
<optional>
<ref name="copy_on_read"/>
</optional>
+ <optional>
+ <ref name="discard"/>
+ </optional>
<empty/>
</element>
</define>
@@ -1399,6 +1402,14 @@
<value>off</value>
</choice>
</attribute>
+ </define>
+ <define name="discard">
+ <attribute name='discard'>
+ <choice>
+ <value>on</value>
+ <value>off</value>
+ </choice>
+ </attribute>
</define>
<define name="controller">
<element name="controller">
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 862b997..f632c02 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -743,6 +743,10 @@ VIR_ENUM_IMPL(virDomainTPMModel, VIR_DOMAIN_TPM_MODEL_LAST,
VIR_ENUM_IMPL(virDomainTPMBackend, VIR_DOMAIN_TPM_TYPE_LAST,
"passthrough")
+VIR_ENUM_IMPL(virDomainDiskDiscard, VIR_DOMAIN_DISK_DISCARD_LAST,
+ "default",
+ "on",
+ "off")
#define VIR_DOMAIN_XML_WRITE_FLAGS VIR_DOMAIN_XML_SECURE
#define VIR_DOMAIN_XML_READ_FLAGS VIR_DOMAIN_XML_INACTIVE
@@ -4534,6 +4538,7 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
char *wwn = NULL;
char *vendor = NULL;
char *product = NULL;
+ char *discard = NULL;
int expected_secret_usage = -1;
int auth_secret_usage = -1;
@@ -4761,6 +4766,7 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
ioeventfd = virXMLPropString(cur, "ioeventfd");
event_idx = virXMLPropString(cur, "event_idx");
copy_on_read = virXMLPropString(cur, "copy_on_read");
+ discard = virXMLPropString(cur, "discard");
} else if (!mirror && xmlStrEqual(cur->name, BAD_CAST "mirror") &&
!(flags & VIR_DOMAIN_XML_INACTIVE)) {
char *ready;
@@ -5207,6 +5213,14 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
def->copy_on_read = cor;
}
+ if (discard) {
+ if ((def->discard = virDomainDiskDiscardTypeFromString(discard)) <= 0) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("unknown disk discard mode '%s'"), discard);
+ goto error;
+ }
+ }
+
if (devaddr) {
if (virDomainParseLegacyDeviceAddress(devaddr,
&def->info.addr.pci) < 0) {
@@ -5326,6 +5340,7 @@ cleanup:
VIR_FREE(ioeventfd);
VIR_FREE(event_idx);
VIR_FREE(copy_on_read);
+ VIR_FREE(discard);
VIR_FREE(devaddr);
VIR_FREE(serial);
virStorageEncryptionFree(encryption);
@@ -13642,6 +13657,7 @@ virDomainDiskDefFormat(virBufferPtr buf,
const char *event_idx = virDomainVirtioEventIdxTypeToString(def->event_idx);
const char *copy_on_read = virDomainVirtioEventIdxTypeToString(def->copy_on_read);
const char *sgio = virDomainDiskSGIOTypeToString(def->sgio);
+ const char *discard = virDomainDiskDiscardTypeToString(def->discard);
char uuidstr[VIR_UUID_STRING_BUFLEN];
@@ -13718,6 +13734,8 @@ virDomainDiskDefFormat(virBufferPtr buf,
virBufferAsprintf(buf, " event_idx='%s'", event_idx);
if (def->copy_on_read)
virBufferAsprintf(buf, " copy_on_read='%s'", copy_on_read);
+ if (def->discard)
+ virBufferAsprintf(buf, " discard='%s'", discard);
virBufferAddLit(buf, "/>\n");
}
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index a9d3410..67ea91e 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -625,6 +625,14 @@ enum virDomainDiskSGIO {
VIR_DOMAIN_DISK_SGIO_LAST
};
+enum virDomainDiskDiscard {
+ VIR_DOMAIN_DISK_DISCARD_DEFAULT = 0,
+ VIR_DOMAIN_DISK_DISCARD_ON,
+ VIR_DOMAIN_DISK_DISCARD_OFF,
+
+ VIR_DOMAIN_DISK_DISCARD_LAST
+};
+
typedef struct _virDomainBlockIoTuneInfo virDomainBlockIoTuneInfo;
struct _virDomainBlockIoTuneInfo {
unsigned long long total_bytes_sec;
@@ -707,6 +715,7 @@ struct _virDomainDiskDef {
bool rawio_specified;
int rawio; /* no = 0, yes = 1 */
int sgio; /* enum virDomainDiskSGIO */
+ int discard; /* enum virDomainDiskDiscard */
size_t nseclabels;
virSecurityDeviceLabelDefPtr *seclabels;
@@ -2462,6 +2471,7 @@ VIR_ENUM_DECL(virDomainDiskIo)
VIR_ENUM_DECL(virDomainDiskSecretType)
VIR_ENUM_DECL(virDomainDiskSGIO)
VIR_ENUM_DECL(virDomainDiskTray)
+VIR_ENUM_DECL(virDomainDiskDiscard)
VIR_ENUM_DECL(virDomainIoEventFd)
VIR_ENUM_DECL(virDomainVirtioEventIdx)
VIR_ENUM_DECL(virDomainDiskCopyOnRead)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index cdd0b41..cc734da 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -142,6 +142,7 @@ virDomainDiskDefFree;
virDomainDiskDefGenSecurityLabelDef;
virDomainDiskDefGetSecurityLabelDef;
virDomainDiskDeviceTypeToString;
+virDomainDiskDiscardTypeToString;
virDomainDiskErrorPolicyTypeFromString;
virDomainDiskErrorPolicyTypeToString;
virDomainDiskFindByBusAndDst;
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index c711e92..e6cb091 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -228,6 +228,7 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST,
"scsi-generic.bootindex", /* 145 */
"mem-merge",
+ "drive-discard",
);
struct _virQEMUCaps {
@@ -2243,6 +2244,7 @@ struct virQEMUCapsCommandLineProps {
static struct virQEMUCapsCommandLineProps virQEMUCapsCommandLine[] = {
{ "machine", "mem-merge", QEMU_CAPS_MEM_MERGE },
+ { "drive", "discard", QEMU_CAPS_DRIVE_DISCARD },
};
static int
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 477e526..e30a550 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -185,6 +185,7 @@ enum virQEMUCapsFlags {
QEMU_CAPS_DEVICE_SCSI_GENERIC = 144, /* -device scsi-generic */
QEMU_CAPS_DEVICE_SCSI_GENERIC_BOOTINDEX = 145, /* -device scsi-generic.bootindex */
QEMU_CAPS_MEM_MERGE = 146, /* -machine mem-merge */
+ QEMU_CAPS_DRIVE_DISCARD = 147, /* -drive discard=off(ignore)|on(unmap) */
QEMU_CAPS_LAST, /* this must always be the last item */
};
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index eddc263..053f553 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3267,6 +3267,17 @@ qemuBuildDriveStr(virConnectPtr conn ATTRIBUTE_UNUSED,
}
}
+ if (disk->discard) {
+ if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DRIVE_DISCARD)) {
+ virBufferAsprintf(&opt, ",discard=%s",
+ virDomainDiskDiscardTypeToString(disk->discard));
+ } else {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("discard is not supported by this QEMU binary"));
+ goto error;
+ }
+ }
+
if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_MONITOR_JSON)) {
const char *wpolicy = NULL, *rpolicy = NULL;
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-discard.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-discard.args
new file mode 100644
index 0000000..02e2ddb
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-discard.args
@@ -0,0 +1,8 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test \
+/usr/bin/qemu -S -M pc-0.13 -m 1024 -smp 1 -nographic -nodefaults \
+-monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot dc -usb \
+-drive file=/var/lib/libvirt/images/f14.img,if=none,id=drive-virtio-disk0,discard=on \
+-device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0 \
+-drive file=/var/lib/libvirt/Fedora-14-x86_64-Live-KDE.iso,if=none,media=cdrom,id=drive-ide0-1-0,discard=off \
+-device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-discard.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-discard.xml
new file mode 100644
index 0000000..a6a8135
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-discard.xml
@@ -0,0 +1,37 @@
+<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='on'/>
+ <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 name='qemu' type='raw' discard='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'/>
+ <controller type='ide' index='0'/>
+ <controller type='pci' index='0' model='pci-root'/>
+ <memballoon model='virtio'/>
+ </devices>
+</domain>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 98ceb83..46dd7de 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -579,6 +579,9 @@ mymain(void)
QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_COPY_ON_READ,
QEMU_CAPS_VIRTIO_TX_ALG, QEMU_CAPS_DEVICE,
QEMU_CAPS_VIRTIO_BLK_SCSI, QEMU_CAPS_VIRTIO_BLK_SG_IO);
+ DO_TEST("disk-drive-discard",
+ QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_DISCARD,
+ QEMU_CAPS_DEVICE);
DO_TEST("disk-snapshot",
QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_CACHE_V2, QEMU_CAPS_DRIVE_FORMAT);
DO_TEST("event_idx",
diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
index 492ac60..ffb0e87 100644
--- a/tests/qemuxml2xmltest.c
+++ b/tests/qemuxml2xmltest.c
@@ -259,6 +259,8 @@ mymain(void)
DO_TEST("disk-scsi-disk-vpd");
DO_TEST("disk-source-pool");
+ DO_TEST("disk-drive-discard");
+
DO_TEST("virtio-rng-random");
DO_TEST("virtio-rng-egd");
--
1.8.1.4
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