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Add directsync cache mode support for disk driver

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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.
This commit is contained in:
Osier Yang 2011-09-02 21:36:58 +08:00
parent ddcd5674aa
commit 6ee52c1b76
10 changed files with 41 additions and 11 deletions
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4
docs/formatdomain.html.in
View File

@ -976,7 +976,9 @@
<li>
The optional <code>cache</code> attribute controls the
cache mechanism, possible values are "default", "none",
"writethrough" and "writeback".
"writethrough", "writeback", and "directsync". "directsync"
is like "writethrough", but it bypasses the host page
cache.
<span class="since">Since 0.6.0</span>
</li>
<li>

1
docs/schemas/domain.rng
View File

@ -829,6 +829,7 @@
<value>none</value>
<value>writeback</value>
<value>writethrough</value>
<value>directsync</value>
</choice>
</attribute>
</define>

3
src/conf/domain_conf.c
View File

@ -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",

1
src/conf/domain_conf.h
View File

@ -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
};

6
src/qemu/qemu_capabilities.c
View File

@ -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="))

1
src/qemu/qemu_capabilities.h
View File

@ -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 */
};

29
src/qemu/qemu_command.c
View File

@ -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"))

1
tests/qemuargv2xmltest.c
View File

@ -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");

3
tests/qemuxml2argvtest.c
View File

@ -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,

3
tools/virsh.pod
View File

@ -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,