Re: [libvirt] [PATCH] Add unsafe cache mode support for disk driver

QEMU 0.13 introduced cache=unsafe for -drive, this patch exposes it in the libvirt layer. * Introduced a new QEMU capability flag ($prefix_CACHE_UNSAFE), as even if $prefix_CACHE_V2 is set, we can't known if unsafe is supported. * qemuhelptest prints test case name on failure. --- docs/formatdomain.html.in | 7 ++-- docs/schemas/domaincommon.rng | 1 + src/conf/domain_conf.c | 3 +- src/conf/domain_conf.h | 1 + src/qemu/qemu_capabilities.c | 3 ++ src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_command.c | 15 ++++++++- tests/qemuargv2xmltest.c | 1 + tests/qemuhelptest.c | 19 ++++++----- .../qemuxml2argv-disk-drive-cache-unsafe.args | 5 +++ .../qemuxml2argv-disk-drive-cache-unsafe.xml | 33 ++++++++++++++++++++ tests/qemuxml2argvtest.c | 3 ++ tools/virsh.pod | 4 +- 13 files changed, 80 insertions(+), 16 deletions(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.xml diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 0a7abaf..8087327 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -996,9 +996,10 @@ <li> The optional<code>cache</code> attribute controls the cache mechanism, possible values are "default", "none", - "writethrough", "writeback", and "directsync". "directsync" - is like "writethrough", but it bypasses the host page - cache. + "writethrough", "writeback", "directsync" (like + "writethrough", but it bypasses the host page cache) and + "unsafe" (host may cache all disk io and sync requests from + guest are ignored). <span class="since">Since 0.6.0</span> </li> <li> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng index d0da41c..be98be0 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -848,6 +848,7 @@ <value>writeback</value> <value>writethrough</value> <value>directsync</value> +<value>unsafe</value> </choice> </attribute> </define> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 7476447..21f4c6b 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -164,7 +164,8 @@ VIR_ENUM_IMPL(virDomainDiskCache, VIR_DOMAIN_DISK_CACHE_LAST, "none", "writethrough", "writeback", - "directsync") + "directsync", + "unsafe") VIR_ENUM_IMPL(virDomainDiskErrorPolicy, VIR_DOMAIN_DISK_ERROR_POLICY_LAST, "default", diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 371f270..86b4c79 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -192,6 +192,7 @@ enum virDomainDiskCache { VIR_DOMAIN_DISK_CACHE_WRITETHRU, VIR_DOMAIN_DISK_CACHE_WRITEBACK, VIR_DOMAIN_DISK_CACHE_DIRECTSYNC, + VIR_DOMAIN_DISK_CACHE_UNSAFE, VIR_DOMAIN_DISK_CACHE_LAST }; diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index 36f47a9..13f1aea 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -136,6 +136,7 @@ VIR_ENUM_IMPL(qemuCaps, QEMU_CAPS_LAST, "pci-ohci", "usb-redir", "usb-hub", + "cache-unsafe", ); struct qemu_feature_flags { @@ -918,6 +919,8 @@ qemuCapsComputeCmdFlags(const char *help, if (strstr(help, "directsync")) qemuCapsSet(flags, QEMU_CAPS_DRIVE_CACHE_DIRECTSYNC); } + if (strstr(help, "|unsafe")) + qemuCapsSet(flags, QEMU_CAPS_DRIVE_CACHE_UNSAFE);

if (strstr(help, "format=")) qemuCapsSet(flags, QEMU_CAPS_DRIVE_FORMAT); if (strstr(help, "readonly=")) diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h index 96b7a3b..97fda0c 100644 --- a/src/qemu/qemu_capabilities.h +++ b/src/qemu/qemu_capabilities.h @@ -110,6 +110,7 @@ enum qemuCapsFlags { QEMU_CAPS_PCI_OHCI = 71, /* -device pci-ohci */ QEMU_CAPS_USB_REDIR = 72, /* -device usb-redir */ QEMU_CAPS_USB_HUB = 73, /* -device usb-hub */ + QEMU_CAPS_DRIVE_CACHE_UNSAFE = 74, /* Is cache=unsafe supported? */ 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 e8b1157..372f9fb 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -66,14 +66,16 @@ VIR_ENUM_IMPL(qemuDiskCacheV1, VIR_DOMAIN_DISK_CACHE_LAST, "off", "off", /* writethrough not supported, so for safety, disable */ "on", /* Old 'on' was equivalent to 'writeback' */ - "off"); /* directsync not supported, for safety, disable */ + "off", /* directsync not supported, for safety, disable */ + "off"); /* unsafe not supported, for safety, disable */ VIR_ENUM_IMPL(qemuDiskCacheV2, VIR_DOMAIN_DISK_CACHE_LAST, "default", "none", "writethrough", "writeback", - "directsync"); + "directsync", + "unsafe"); VIR_ENUM_DECL(qemuVideo) @@ -1623,6 +1625,13 @@ qemuBuildDriveStr(virDomainDiskDefPtr disk, "supported by this QEMU")); goto error; } + else if (disk->cachemode == VIR_DOMAIN_DISK_CACHE_UNSAFE&&

+ !qemuCapsGet(qemuCaps, QEMU_CAPS_DRIVE_CACHE_UNSAFE)) { + qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("disk cache mode 'unsafe' is not " + "supported by this QEMU")); + goto error; + } } else { mode = qemuDiskCacheV1TypeToString(disk->cachemode); } @@ -5536,6 +5545,8 @@ qemuParseCommandLineDisk(virCapsPtr caps, def->cachemode = VIR_DOMAIN_DISK_CACHE_WRITETHRU; else if (STREQ(values[i], "directsync")) def->cachemode = VIR_DOMAIN_DISK_CACHE_DIRECTSYNC; + else if (STREQ(values[i], "unsafe")) + def->cachemode = VIR_DOMAIN_DISK_CACHE_UNSAFE; } else if (STREQ(keywords[i], "werror") || STREQ(keywords[i], "rerror")) { if (STREQ(values[i], "stop")) diff --git a/tests/qemuargv2xmltest.c b/tests/qemuargv2xmltest.c index 91f15af..6a79630 100644 --- a/tests/qemuargv2xmltest.c +++ b/tests/qemuargv2xmltest.c @@ -169,6 +169,7 @@ mymain(void) DO_TEST("disk-drive-cache-v2-wb"); DO_TEST("disk-drive-cache-v2-none"); DO_TEST("disk-drive-cache-directsync"); + DO_TEST("disk-drive-cache-unsafe"); DO_TEST("disk-drive-network-nbd"); DO_TEST("disk-drive-network-rbd"); DO_TEST("disk-drive-network-sheepdog"); diff --git a/tests/qemuhelptest.c b/tests/qemuhelptest.c index ffd30e2..4d757e5 100644 --- a/tests/qemuhelptest.c +++ b/tests/qemuhelptest.c @@ -77,8 +77,8 @@ static int testHelpStrParsing(const void *data) if (STRNEQ(got, expected)) { fprintf(stderr, - "Computed flags do not match: got %s, expected %s\n", - got, expected); + "%s: computed flags do not match: got %s, expected %s\n", + info->name, got, expected); if (getenv("VIR_TEST_DEBUG")) printMismatchedFlags(flags, info->flags); @@ -87,22 +87,22 @@ static int testHelpStrParsing(const void *data) } if (version != info->version) { - fprintf(stderr, "Parsed versions do not match: got %u, expected %u\n", - version, info->version); + fprintf(stderr, "%s: parsed versions do not match: got %u, expected %u\n", + info->name, version, info->version); goto cleanup; } if (is_kvm != info->is_kvm) { fprintf(stderr, - "Parsed is_kvm flag does not match: got %u, expected %u\n", - is_kvm, info->is_kvm); + "%s: parsed is_kvm flag does not match: got %u, expected %u\n", + info->name, is_kvm, info->is_kvm); goto cleanup; } if (kvm_version != info->kvm_version) { fprintf(stderr, - "Parsed KVM versions do not match: got %u, expected %u\n", - kvm_version, info->kvm_version); + "%s: parsed KVM versions do not match: got %u, expected %u\n", + info->name, kvm_version, info->kvm_version); goto cleanup; } @@ -164,6 +164,7 @@ mymain(void) QEMU_CAPS_MIGRATE_QEMU_TCP, QEMU_CAPS_MIGRATE_QEMU_EXEC, QEMU_CAPS_DRIVE_CACHE_V2, + QEMU_CAPS_DRIVE_CACHE_UNSAFE, QEMU_CAPS_KVM, QEMU_CAPS_DRIVE_FORMAT, QEMU_CAPS_DRIVE_SERIAL, @@ -399,6 +400,7 @@ mymain(void) QEMU_CAPS_MIGRATE_QEMU_TCP, QEMU_CAPS_MIGRATE_QEMU_EXEC, QEMU_CAPS_DRIVE_CACHE_V2, + QEMU_CAPS_DRIVE_CACHE_UNSAFE, QEMU_CAPS_KVM, QEMU_CAPS_DRIVE_FORMAT, QEMU_CAPS_DRIVE_SERIAL, @@ -450,6 +452,7 @@ mymain(void) QEMU_CAPS_MIGRATE_QEMU_TCP, QEMU_CAPS_MIGRATE_QEMU_EXEC, QEMU_CAPS_DRIVE_CACHE_V2, + QEMU_CAPS_DRIVE_CACHE_UNSAFE, QEMU_CAPS_KVM, QEMU_CAPS_DRIVE_FORMAT, QEMU_CAPS_DRIVE_SERIAL, diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.args new file mode 100644 index 0000000..f8ddcd8 --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.args @@ -0,0 +1,5 @@ +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M \ +pc -m 214 -smp 1 -nographic -monitor unix:/tmp/test-monitor,server,nowait \ +-no-acpi -boot c -drive file=/dev/HostVG/QEMUGuest1,if=ide,bus=0,unit=0,\ +format=qcow2,cache=unsafe -drive file=/dev/HostVG/QEMUGuest2,if=ide,\ +media=cdrom,bus=1,unit=0,format=raw -net none -serial none -parallel none -usb diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.xml new file mode 100644 index 0000000..37185f6 --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-cache-unsafe.xml @@ -0,0 +1,33 @@ +<domain type='qemu'> +<name>QEMUGuest1</name> +<uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid> +<memory>219136</memory> +<currentMemory>219136</currentMemory> +<vcpu>1</vcpu> +<os> +<type arch='i686' machine='pc'>hvm</type> +<boot dev='hd'/> +</os> +<clock offset='utc'/> +<on_poweroff>destroy</on_poweroff> +<on_reboot>restart</on_reboot> +<on_crash>destroy</on_crash> +<devices> +<emulator>/usr/bin/qemu</emulator> +<disk type='block' device='disk'> +<driver name='qemu' type='qcow2' cache='unsafe'/> +<source dev='/dev/HostVG/QEMUGuest1'/> +<target dev='hda' bus='ide'/> +<address type='drive' controller='0' bus='0' unit='0'/> +</disk> +<disk type='block' device='cdrom'> +<driver name='qemu' type='raw'/> +<source dev='/dev/HostVG/QEMUGuest2'/> +<target dev='hdc' bus='ide'/> +<readonly/> +<address type='drive' controller='0' bus='1' unit='0'/> +</disk> +<controller type='ide' index='0'/> +<memballoon model='virtio'/> +</devices> +</domain> diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c index fcb20bb..97b61d1 100644 --- a/tests/qemuxml2argvtest.c +++ b/tests/qemuxml2argvtest.c @@ -341,6 +341,9 @@ mymain(void) DO_TEST("disk-drive-cache-directsync", false, QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_CACHE_V2, QEMU_CAPS_DRIVE_CACHE_DIRECTSYNC, QEMU_CAPS_DRIVE_FORMAT); + DO_TEST("disk-drive-cache-unsafe", false, + QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_CACHE_V2, + QEMU_CAPS_DRIVE_CACHE_UNSAFE, QEMU_CAPS_DRIVE_FORMAT); DO_TEST("disk-drive-network-nbd", false, QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_FORMAT); DO_TEST("disk-drive-network-rbd", false, diff --git a/tools/virsh.pod b/tools/virsh.pod index 02726f3..73ed045 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -1173,8 +1173,8 @@ floppy device; consider using B<update-device> for this usage instead. I<mode> can specify the two specific mode I<readonly> or I<shareable>. I<persistent> indicates the changes will affect the next boot of the domain. I<sourcetype> can indicate the type of source (block|file) -I<cache> can be one of "default", "none", "writethrough", "writeback", or -"directsync". +I<cache> can be one of "default", "none", "writethrough", "writeback", +"directsync" or "unsafe". I<serial> is the serial of disk device. I<shareable> indicates the disk device is shareable between domains. I<address> is the address of disk device in the form of pci:domain.bus.slot.function,