[libvirt] [PATCH] Add directsync cache mode support for disk driver
Osier Yang
jyang at redhat.com
Fri Sep 2 07:38:38 UTC 2011
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,
--
1.7.6
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