[libvirt] [PATCH] Add directsync cache mode support for disk driver
Daniel Veillard
veillard at redhat.com
Fri Sep 2 10:04:21 UTC 2011
On Fri, Sep 02, 2011 at 03:38:38PM +0800, Osier Yang wrote:
> Newer QEMU introduced cache=directsync for -drive, this patchset
> is to expose it in libvirt layer.
>
> * Introduced a new QEMU capability flag ($prefix_CACHE_DIRECTSYNC),
> As even $prefix_CACHE_V2 is set, we can't known if directsync
> is supported.
> ---
> docs/formatdomain.html.in | 2 +-
> docs/schemas/domain.rng | 1 +
> src/conf/domain_conf.c | 3 ++-
> src/conf/domain_conf.h | 1 +
> src/qemu/qemu_capabilities.c | 6 +++++-
> src/qemu/qemu_capabilities.h | 1 +
> src/qemu/qemu_command.c | 29 ++++++++++++++++++++++-------
> tests/qemuargv2xmltest.c | 1 +
> tests/qemuxml2argvtest.c | 3 +++
> tools/virsh.pod | 3 ++-
> 10 files changed, 39 insertions(+), 11 deletions(-)
>
> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> index f46771d..6cb36d3 100644
> --- a/docs/formatdomain.html.in
> +++ b/docs/formatdomain.html.in
> @@ -976,7 +976,7 @@
> <li>
> The optional <code>cache</code> attribute controls the
> cache mechanism, possible values are "default", "none",
> - "writethrough" and "writeback".
> + "writethrough", "writeback", and "directsync".
> <span class="since">Since 0.6.0</span>
> </li>
> <li>
> diff --git a/docs/schemas/domain.rng b/docs/schemas/domain.rng
> index dd8c41a..e43b17d 100644
> --- a/docs/schemas/domain.rng
> +++ b/docs/schemas/domain.rng
> @@ -829,6 +829,7 @@
> <value>none</value>
> <value>writeback</value>
> <value>writethrough</value>
> + <value>directsync</value>
> </choice>
> </attribute>
> </define>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 00212db..a2de8df 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -160,7 +160,8 @@ VIR_ENUM_IMPL(virDomainDiskCache, VIR_DOMAIN_DISK_CACHE_LAST,
> "default",
> "none",
> "writethrough",
> - "writeback")
> + "writeback",
> + "directsync")
>
> 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 8382d28..0abb75e 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -165,6 +165,7 @@ enum virDomainDiskCache {
> VIR_DOMAIN_DISK_CACHE_DISABLE,
> VIR_DOMAIN_DISK_CACHE_WRITETHRU,
> VIR_DOMAIN_DISK_CACHE_WRITEBACK,
> + VIR_DOMAIN_DISK_CACHE_DIRECTSYNC,
>
> VIR_DOMAIN_DISK_CACHE_LAST
> };
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index f665de4..631d683 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -125,6 +125,7 @@ VIR_ENUM_IMPL(qemuCaps, QEMU_CAPS_LAST,
> "sga",
> "virtio-blk-pci.event_idx",
> "virtio-net-pci.event_idx",
> + "cache-directsync",
> );
>
> struct qemu_feature_flags {
> @@ -902,8 +903,11 @@ qemuCapsComputeCmdFlags(const char *help,
> if (strstr(help, "-drive")) {
> qemuCapsSet(flags, QEMU_CAPS_DRIVE);
> if (strstr(help, "cache=") &&
> - !strstr(help, "cache=on|off"))
> + !strstr(help, "cache=on|off")) {
> qemuCapsSet(flags, QEMU_CAPS_DRIVE_CACHE_V2);
> + if (strstr(help, "directsync"))
> + qemuCapsSet(flags, QEMU_CAPS_DRIVE_CACHE_DIRECTSYNC);
> + }
> 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 13af0b9..c01d438 100644
> --- a/src/qemu/qemu_capabilities.h
> +++ b/src/qemu/qemu_capabilities.h
> @@ -100,6 +100,7 @@ enum qemuCapsFlags {
> QEMU_CAPS_SGA = 62, /* Serial Graphics Adapter */
> QEMU_CAPS_VIRTIO_BLK_EVENT_IDX = 63, /* virtio-blk-pci.event_idx */
> QEMU_CAPS_VIRTIO_NET_EVENT_IDX = 64, /* virtio-net-pci.event_idx */
> + QEMU_CAPS_DRIVE_CACHE_DIRECTSYNC = 65, /* Is cache=directsync 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 44a553b..fa52dc0 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -64,14 +64,16 @@ VIR_ENUM_DECL(qemuDiskCacheV2)
> VIR_ENUM_IMPL(qemuDiskCacheV1, VIR_DOMAIN_DISK_CACHE_LAST,
> "default",
> "off",
> - "off", /* writethrough not supported, so for safety, disable */
> - "on"); /* Old 'on' was equivalent to 'writeback' */
> + "off", /* writethrough not supported, so for safety, disable */
> + "on", /* Old 'on' was equivalent to 'writeback' */
> + "off"); /* directsync not supported, for safety, disable */
>
> VIR_ENUM_IMPL(qemuDiskCacheV2, VIR_DOMAIN_DISK_CACHE_LAST,
> "default",
> "none",
> "writethrough",
> - "writeback");
> + "writeback",
> + "directsync");
>
> VIR_ENUM_DECL(qemuVideo)
>
> @@ -1516,10 +1518,21 @@ qemuBuildDriveStr(virDomainDiskDefPtr disk,
> }
>
> if (disk->cachemode) {
> - const char *mode =
> - qemuCapsGet(qemuCaps, QEMU_CAPS_DRIVE_CACHE_V2) ?
> - qemuDiskCacheV2TypeToString(disk->cachemode) :
> - qemuDiskCacheV1TypeToString(disk->cachemode);
> + const char *mode = NULL;
> +
> + if (qemuCapsGet(qemuCaps, QEMU_CAPS_DRIVE_CACHE_V2)) {
> + mode = qemuDiskCacheV2TypeToString(disk->cachemode);
> +
> + if (disk->cachemode == VIR_DOMAIN_DISK_CACHE_DIRECTSYNC &&
> + !qemuCapsGet(qemuCaps, QEMU_CAPS_DRIVE_CACHE_DIRECTSYNC)) {
> + qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> + _("disk cache mode 'directsync' is not "
> + "supported by this QEMU"));
> + goto error;
> + }
> + } else {
> + mode = qemuDiskCacheV1TypeToString(disk->cachemode);
> + }
>
> virBufferAsprintf(&opt, ",cache=%s", mode);
> } else if (disk->shared && !disk->readonly) {
> @@ -5211,6 +5224,8 @@ qemuParseCommandLineDisk(virCapsPtr caps,
> def->cachemode = VIR_DOMAIN_DISK_CACHE_WRITEBACK;
> else if (STREQ(values[i], "writethrough"))
> def->cachemode = VIR_DOMAIN_DISK_CACHE_WRITETHRU;
> + else if (STREQ(values[i], "directsync"))
> + def->cachemode = VIR_DOMAIN_DISK_CACHE_DIRECTSYNC;
> } 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 c2b6cf2..91f15af 100644
> --- a/tests/qemuargv2xmltest.c
> +++ b/tests/qemuargv2xmltest.c
> @@ -168,6 +168,7 @@ mymain(void)
> DO_TEST("disk-drive-cache-v2-wt");
> DO_TEST("disk-drive-cache-v2-wb");
> DO_TEST("disk-drive-cache-v2-none");
> + DO_TEST("disk-drive-cache-directsync");
> DO_TEST("disk-drive-network-nbd");
> DO_TEST("disk-drive-network-rbd");
> DO_TEST("disk-drive-network-sheepdog");
> diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
> index 6e8da5e..b009bf3 100644
> --- a/tests/qemuxml2argvtest.c
> +++ b/tests/qemuxml2argvtest.c
> @@ -338,6 +338,9 @@ mymain(void)
> QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_CACHE_V2, QEMU_CAPS_DRIVE_FORMAT);
> DO_TEST("disk-drive-cache-v2-none", false,
> QEMU_CAPS_DRIVE, QEMU_CAPS_DRIVE_CACHE_V2, QEMU_CAPS_DRIVE_FORMAT);
> + 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-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 b90c26e..5ac2c5c 100644
> --- a/tools/virsh.pod
> +++ b/tools/virsh.pod
> @@ -1099,7 +1099,8 @@ 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" or "writeback".
> +I<cache> can be one of "default", "none", "writethrough", "writeback", or
> +"directsync".
> 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,
ACK, though I would prefer if docs/formatdomain.html.in was expanded
to explain the semantic of that new flag !
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel at veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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