[libvirt] [PATCH v2] qemu: Support copy on read for disk

The new introduced optional attribute "copy_on_read</code> controls wether to copy read backing file into the image file. The value can be either "on" or "off". Copy-on-read avoids accessing the same backing file sectors repeatedly and is useful when the backing file is over a slow network. By default copy-on-read is off. --- docs/formatdomain.html.in | 9 ++++ docs/schemas/domaincommon.rng | 11 ++++ src/conf/domain_conf.c | 24 +++++++++- src/conf/domain_conf.h | 10 ++++ src/libvirt_private.syms | 2 + src/qemu/qemu_capabilities.c | 3 + src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_command.c | 11 ++++ tests/qemuhelptest.c | 3 +- .../qemuxml2argv-disk-copy_on_read.args | 11 ++++ .../qemuxml2argv-disk-copy_on_read.xml | 50 ++++++++++++++++++++ tests/qemuxml2argvtest.c | 4 ++ 12 files changed, 137 insertions(+), 2 deletions(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.xml diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 42e23a1..3a42ebb 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1202,6 +1202,15 @@ <b>In general you should leave this option alone, unless you are very certain you know what you are doing.</b> </li> + <li> + The optional <code>copy_on_read</code> attribute controls + wether to copy read backing file into the image file. The + value can be either "on" or "off". + Copy-on-read avoids accessing the same backing file sectors + repeatedly and is useful when the backing file is over a slow + network. By default copy-on-read is off. + <span class='since'>Since 0.9.9 (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 e93ae77..fdcbc28 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -958,6 +958,9 @@ <optional> <ref name="event_idx"/> </optional> + <optional> + <ref name="copy_on_read"/> + </optional> <empty/> </element> </define> @@ -1025,6 +1028,14 @@ </choice> </attribute> </define> + <define name="copy_on_read"> + <attribute name='copy_on_read'> + <choice> + <value>on</value> + <value>off</value> + </choice> + </attribute> + </define> <define name="controller"> <element name="controller"> <choice> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 180dd2b..c70faee 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -209,6 +209,11 @@ VIR_ENUM_IMPL(virDomainVirtioEventIdx, VIR_DOMAIN_VIRTIO_EVENT_IDX_LAST, "on", "off") +VIR_ENUM_IMPL(virDomainDiskCopyOnRead, VIR_DOMAIN_DISK_COPY_ON_READ_LAST, + "default", + "on", + "off") + VIR_ENUM_IMPL(virDomainDiskSnapshot, VIR_DOMAIN_DISK_SNAPSHOT_LAST, "default", "no", @@ -2783,6 +2788,7 @@ virDomainDiskDefParseXML(virCapsPtr caps, char *iotag = NULL; char *ioeventfd = NULL; char *event_idx = NULL; + char *copy_on_read = NULL; char *devaddr = NULL; virStorageEncryptionPtr encryption = NULL; char *serial = NULL; @@ -2911,6 +2917,7 @@ virDomainDiskDefParseXML(virCapsPtr caps, iotag = virXMLPropString(cur, "io"); ioeventfd = virXMLPropString(cur, "ioeventfd"); event_idx = virXMLPropString(cur, "event_idx"); + copy_on_read = virXMLPropString(cur, "copy_on_read"); } else if (xmlStrEqual(cur->name, BAD_CAST "auth")) { authUsername = virXMLPropString(cur, "username"); if (authUsername == NULL) { @@ -3226,6 +3233,17 @@ virDomainDiskDefParseXML(virCapsPtr caps, def->event_idx = idx; } + if (copy_on_read) { + int cor; + if ((cor = virDomainDiskCopyOnReadTypeFromString(copy_on_read)) <= 0) { + virDomainReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("unknown disk copy_on_read mode '%s'"), + copy_on_read); + goto error; + } + def->copy_on_read = cor; + } + if (devaddr) { if (virDomainParseLegacyDeviceAddress(devaddr, &def->info.addr.pci) < 0) { @@ -3319,6 +3337,7 @@ cleanup: VIR_FREE(iotag); VIR_FREE(ioeventfd); VIR_FREE(event_idx); + VIR_FREE(copy_on_read); VIR_FREE(devaddr); VIR_FREE(serial); virStorageEncryptionFree(encryption); @@ -9870,6 +9889,7 @@ virDomainDiskDefFormat(virBufferPtr buf, const char *iomode = virDomainDiskIoTypeToString(def->iomode); const char *ioeventfd = virDomainIoEventFdTypeToString(def->ioeventfd); const char *event_idx = virDomainVirtioEventIdxTypeToString(def->event_idx); + const char *copy_on_read = virDomainVirtioEventIdxTypeToString(def->copy_on_read); const char *startupPolicy = virDomainStartupPolicyTypeToString(def->startupPolicy); char uuidstr[VIR_UUID_STRING_BUFLEN]; @@ -9910,7 +9930,7 @@ virDomainDiskDefFormat(virBufferPtr buf, virBufferAddLit(buf, ">\n"); if (def->driverName || def->driverType || def->cachemode || - def->ioeventfd || def->event_idx) { + def->ioeventfd || def->event_idx || def->copy_on_read) { virBufferAddLit(buf, " <driver"); if (def->driverName) virBufferAsprintf(buf, " name='%s'", def->driverName); @@ -9928,6 +9948,8 @@ virDomainDiskDefFormat(virBufferPtr buf, virBufferAsprintf(buf, " ioeventfd='%s'", ioeventfd); if (def->event_idx) virBufferAsprintf(buf, " event_idx='%s'", event_idx); + if (def->copy_on_read) + virBufferAsprintf(buf, " copy_on_read='%s'", copy_on_read); virBufferAddLit(buf, "/>\n"); } diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 3d5d4f8..bac5a87 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -308,6 +308,14 @@ enum virDomainVirtioEventIdx { VIR_DOMAIN_VIRTIO_EVENT_IDX_LAST }; +enum virDomainDiskCopyOnRead { + VIR_DOMAIN_DISK_COPY_ON_READ_DEFAULT = 0, + VIR_DOMAIN_DISK_COPY_ON_READ_ON, + VIR_DOMAIN_DISK_COPY_ON_READ_OFF, + + VIR_DOMAIN_DISK_COPY_ON_READ_LAST +}; + enum virDomainDiskSnapshot { VIR_DOMAIN_DISK_SNAPSHOT_DEFAULT = 0, VIR_DOMAIN_DISK_SNAPSHOT_NO, @@ -384,6 +392,7 @@ struct _virDomainDiskDef { int iomode; int ioeventfd; int event_idx; + int copy_on_read; int snapshot; /* enum virDomainDiskSnapshot */ int startupPolicy; /* enum virDomainStartupPolicy */ unsigned int readonly : 1; @@ -1969,6 +1978,7 @@ VIR_ENUM_DECL(virDomainDiskSecretType) VIR_ENUM_DECL(virDomainDiskSnapshot) VIR_ENUM_DECL(virDomainIoEventFd) VIR_ENUM_DECL(virDomainVirtioEventIdx) +VIR_ENUM_DECL(virDomainDiskCopyOnRead) VIR_ENUM_DECL(virDomainController) VIR_ENUM_DECL(virDomainControllerModelSCSI) VIR_ENUM_DECL(virDomainControllerModelUSB) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index ca4beb1..27a093c 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -290,6 +290,8 @@ virDomainDeviceTypeToString; virDomainDiskBusTypeToString; virDomainDiskCacheTypeFromString; virDomainDiskCacheTypeToString; +virDomainDiskCopyOnReadTypeFromString; +virDomainDiskCopyOnReadTypeToString; virDomainDiskDefAssignAddress; virDomainDiskDefForeachPath; virDomainDiskDefFree; diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index 6842cfe..530bbb1 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -147,6 +147,7 @@ VIR_ENUM_IMPL(qemuCaps, QEMU_CAPS_LAST, "virtio-blk-pci.scsi", "blk-sg-io", + "drive-copy-on-read", ); struct qemu_feature_flags { @@ -1026,6 +1027,8 @@ qemuCapsComputeCmdFlags(const char *help, qemuCapsSet(flags, QEMU_CAPS_DRIVE_READONLY); if (strstr(help, "aio=threads|native")) qemuCapsSet(flags, QEMU_CAPS_DRIVE_AIO); + if (strstr(help, "copy-on-read=on|off")) + qemuCapsSet(flags, QEMU_CAPS_DRIVE_COPY_ON_READ); } if ((p = strstr(help, "-vga")) && !strstr(help, "-std-vga")) { const char *nl = strstr(p, "\n"); diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h index d47177c..ee9d5ab 100644 --- a/src/qemu/qemu_capabilities.h +++ b/src/qemu/qemu_capabilities.h @@ -120,6 +120,7 @@ enum qemuCapsFlags { QEMU_CAPS_VIRTIO_BLK_SCSI = 80, /* virtio-blk-pci.scsi */ QEMU_CAPS_VIRTIO_BLK_SG_IO = 81, /* support for SG_IO commands, reportedly added in 0.11 */ + QEMU_CAPS_DRIVE_COPY_ON_READ = 82, /* -drive copy-on-read */ 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 16ffb4c..ee51965 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -1929,6 +1929,17 @@ qemuBuildDriveStr(virConnectPtr conn ATTRIBUTE_UNUSED, virBufferAddLit(&opt, ",cache=off"); } + if (disk->copy_on_read) { + if (qemuCapsGet(qemuCaps, QEMU_CAPS_DRIVE_COPY_ON_READ)) { + virBufferAsprintf(&opt, ",copy-on-read=%s", + virDomainDiskCopyOnReadTypeToString(disk->copy_on_read)); + } else { + qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("copy_on_read is not supported by this QEMU binary")); + goto error; + } + } + if (qemuCapsGet(qemuCaps, QEMU_CAPS_MONITOR_JSON)) { const char *wpolicy = NULL, *rpolicy = NULL; diff --git a/tests/qemuhelptest.c b/tests/qemuhelptest.c index 1ef0d9b..2b08af9 100644 --- a/tests/qemuhelptest.c +++ b/tests/qemuhelptest.c @@ -592,7 +592,8 @@ mymain(void) QEMU_CAPS_PCI_ROMBAR, QEMU_CAPS_NO_ACPI, QEMU_CAPS_VIRTIO_BLK_SCSI, - QEMU_CAPS_VIRTIO_BLK_SG_IO); + QEMU_CAPS_VIRTIO_BLK_SG_IO, + QEMU_CAPS_DRIVE_COPY_ON_READ); DO_TEST("qemu-1.0", 1000000, 0, 0, QEMU_CAPS_VNC_COLON, QEMU_CAPS_NO_REBOOT, diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.args new file mode 100644 index 0000000..2ca586d --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.args @@ -0,0 +1,11 @@ +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \ +/usr/bin/qemu -S -M pc-0.13 -m 1024 -smp 1 -nodefaults \ +-monitor unix:/tmp/test-monitor,server,nowait -no-acpi \ +-boot dc -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 \ +-drive file=/var/lib/libvirt/images/f14.img,if=none,id=drive-virtio-disk0,copy-on-read=on \ +-device virtio-blk-pci,scsi=off,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 \ +-device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 \ +-device virtio-net-pci,tx=bh,vlan=0,id=net0,mac=52:54:00:e5:48:58,bus=pci.0,addr=0x3 \ +-net user,vlan=0,name=hostnet0 -serial pty -usb -vnc 127.0.0.1:-809 -std-vga \ +-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.xml new file mode 100644 index 0000000..433c641 --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.xml @@ -0,0 +1,50 @@ +<domain type='qemu'> + <name>test</name> + <memory>1048576</memory> + <vcpu>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' copy_on_read='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'/> + <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' unit='0'/> + </disk> + <interface type='user'> + <mac address='52:54:00:e5:48:58'/> + <model type='virtio'/> + <driver name='vhost' txmode='iothread'/> + </interface> + <controller type='virtio-serial' index='0'> + <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> + </controller> + <serial type='pty'> + <target port='0'/> + </serial> + <console type='pty'> + <target type='serial' port='0'/> + </console> + <graphics type='vnc' port='5091' autoport='no' listen='127.0.0.1'/> + <video> + <model type='vga' vram='9216' heads='1'/> + <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> + </video> + </devices> +</domain> diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c index d87654c..30bea37 100644 --- a/tests/qemuxml2argvtest.c +++ b/tests/qemuxml2argvtest.c @@ -439,6 +439,10 @@ mymain(void) QEMU_CAPS_DRIVE, QEMU_CAPS_VIRTIO_IOEVENTFD, QEMU_CAPS_VIRTIO_TX_ALG, QEMU_CAPS_DEVICE, QEMU_CAPS_VIRTIO_BLK_SCSI, QEMU_CAPS_VIRTIO_BLK_SG_IO); + DO_TEST("disk-copy_on_read", false, + 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-snapshot", false, QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_CACHE_V2, QEMU_CAPS_DRIVE_FORMAT); DO_TEST("event_idx", false, -- 1.7.7.3