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blockcopy: add more XML for state tracking 

Doing a blockcopy operation across a libvirtd restart is not very
robust at the moment.  In particular, we are clearing the <mirror>
element prior to telling qemu to finish the job.  Also, thanks to the
ability to request async completion, the user can easily regain
control prior to qemu actually finishing the effort, and they should
be able to poll the domain XML to see if the job is still going.

A future patch will fix things to actually wait until qemu is done
before modifying the XML to reflect the job completion.  But since
qemu issues identical BLOCK_JOB_COMPLETE events regardless of whether
the job was cancelled (kept the original disk) or completed (pivoted
to the new disk), we have to track which of the two operations were
used to end the job.  Furthermore, we'd like to avoid attempts to
end a job where we are already waiting on an earlier request to qemu
to end the job.  Likewise, if we miss the qemu event (perhaps because
it arrived during a libvirtd restart), we still need enough state
recorded to be able to determine how to modify the domain XML once
we reconnect to qemu and manually learn whether the job still exists.

Although this patch doesn't actually fix the problem, it is a
preliminary step that makes it possible to track whether a job
has already begun steps towards completion.

* src/conf/domain_conf.h (virDomainDiskMirrorState): New enum.
(_virDomainDiskDef): Convert bool mirroring to new enum.
* src/conf/domain_conf.c (virDomainDiskDefParseXML)
(virDomainDiskDefFormat): Handle new values.
* src/qemu/qemu_process.c (qemuProcessHandleBlockJob): Adjust
client.
* src/qemu/qemu_driver.c (qemuDomainBlockPivot)
(qemuDomainBlockJobImpl): Likewise.
* docs/schemas/domaincommon.rng (diskMirror): Expose new values.
* docs/formatdomain.html.in (elementsDisks): Document it.
* tests/qemuxml2argvdata/qemuxml2argv-disk-mirror.xml: Test it.

Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Eric Blake 2014-07-28 16:25:28 -06:00
parent c5b02b6773
commit 9a212d6708
7 changed files with 56 additions and 16 deletions
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10
docs/formatdomain.html.in
View File

@ -1921,9 +1921,13 @@
format of the source). The details of the <code>source</code>
sub-element are determined by the <code>type</code> attribute
of the mirror, similar to what is done for the
overall <code>disk</code> device element. If
attribute <code>ready</code> is present, then it is known the
disk is ready to pivot; otherwise, the disk is probably still
overall <code>disk</code> device element. The
attribute <code>ready</code>, if present, tracks progress of
the job: <code>yes</code> if the disk is known to be ready to
pivot, or, <span class="since">since
1.2.7</span>, <code>abort</code> or <code>pivot</code> if the
job is in the process of completing. If <code>ready</code> is
not present, the disk is probably still
copying. For now, this element only valid in output; it is
ignored on input. The <code>source</code> sub-element exists
for all two-phase jobs <span class="since">since 1.2.6</span>.

6
docs/schemas/domaincommon.rng
View File

@ -4309,7 +4309,11 @@
</choice>
<optional>
<attribute name='ready'>
<value>yes</value>
<choice>
<value>yes</value>
<value>abort</value>
<value>pivot</value>
</choice>
</attribute>
</optional>
</element>

23
src/conf/domain_conf.c
View File

@ -747,6 +747,12 @@ VIR_ENUM_IMPL(virDomainDiskDiscard, VIR_DOMAIN_DISK_DISCARD_LAST,
"unmap",
"ignore")
VIR_ENUM_IMPL(virDomainDiskMirrorState, VIR_DOMAIN_DISK_MIRROR_STATE_LAST,
"none",
"yes",
"abort",
"pivot")
#define VIR_DOMAIN_XML_WRITE_FLAGS VIR_DOMAIN_XML_SECURE
#define VIR_DOMAIN_XML_READ_FLAGS VIR_DOMAIN_XML_INACTIVE
@ -5482,7 +5488,14 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
}
ready = virXMLPropString(cur, "ready");
if (ready) {
def->mirroring = true;
if ((def->mirrorState =
virDomainDiskMirrorStateTypeFromString(ready)) < 0) {
virReportError(VIR_ERR_XML_ERROR,
_("unknown mirror ready state %s"),
ready);
VIR_FREE(ready);
goto error;
}
VIR_FREE(ready);
}
} else if (xmlStrEqual(cur->name, BAD_CAST "auth")) {
@ -15392,8 +15405,12 @@ virDomainDiskDefFormat(virBufferPtr buf,
virBufferEscapeString(buf, " file='%s'", def->mirror->path);
virBufferEscapeString(buf, " format='%s'", formatStr);
}
if (def->mirroring)
virBufferAddLit(buf, " ready='yes'");
if (def->mirrorState) {
const char *mirror;
mirror = virDomainDiskMirrorStateTypeToString(def->mirrorState);
virBufferEscapeString(buf, " ready='%s'", mirror);
}
virBufferAddLit(buf, ">\n");
virBufferAdjustIndent(buf, 2);
virBufferEscapeString(buf, "<format type='%s'/>\n", formatStr);

13
src/conf/domain_conf.h
View File

@ -610,6 +610,16 @@ struct _virDomainBlockIoTuneInfo {
typedef virDomainBlockIoTuneInfo *virDomainBlockIoTuneInfoPtr;
typedef enum {
VIR_DOMAIN_DISK_MIRROR_STATE_NONE = 0, /* No job, or job still not synced */
VIR_DOMAIN_DISK_MIRROR_STATE_READY, /* Job in second phase */
VIR_DOMAIN_DISK_MIRROR_STATE_ABORT, /* Job aborted, waiting for event */
VIR_DOMAIN_DISK_MIRROR_STATE_PIVOT, /* Job pivoted, waiting for event */
VIR_DOMAIN_DISK_MIRROR_STATE_LAST
} virDomainDiskMirrorState;
/* Stores the virtual disk configuration */
struct _virDomainDiskDef {
virStorageSourcePtr src; /* non-NULL. XXX Allow NULL for empty cdrom? */
@ -621,7 +631,7 @@ struct _virDomainDiskDef {
int removable; /* enum virTristateSwitch */
virStorageSourcePtr mirror;
bool mirroring;
int mirrorState; /* enum virDomainDiskMirrorState */
struct {
unsigned int cylinders;
@ -2567,6 +2577,7 @@ VIR_ENUM_DECL(virDomainDiskIo)
VIR_ENUM_DECL(virDomainDeviceSGIO)
VIR_ENUM_DECL(virDomainDiskTray)
VIR_ENUM_DECL(virDomainDiskDiscard)
VIR_ENUM_DECL(virDomainDiskMirrorState)
VIR_ENUM_DECL(virDomainController)
VIR_ENUM_DECL(virDomainControllerModelPCI)
VIR_ENUM_DECL(virDomainControllerModelSCSI)

12
src/qemu/qemu_driver.c
View File

@ -14841,7 +14841,7 @@ qemuDomainBlockPivot(virConnectPtr conn,
format = virStorageFileFormatTypeToString(disk->mirror->format);
/* Probe the status, if needed. */
if (!disk->mirroring) {
if (!disk->mirrorState) {
qemuDomainObjEnterMonitor(driver, vm);
rc = qemuMonitorBlockJob(priv->mon, device, NULL, NULL, 0, &info,
BLOCK_JOB_INFO, true);
@ -14855,10 +14855,10 @@ qemuDomainBlockPivot(virConnectPtr conn,
}
if (rc == 1 && info.cur == info.end &&
info.type == VIR_DOMAIN_BLOCK_JOB_TYPE_COPY)
disk->mirroring = true;
disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_READY;
}
if (!disk->mirroring) {
if (disk->mirrorState != VIR_DOMAIN_DISK_MIRROR_STATE_READY) {
virReportError(VIR_ERR_BLOCK_COPY_ACTIVE,
_("disk '%s' not ready for pivot yet"),
disk->dst);
@ -14934,7 +14934,7 @@ qemuDomainBlockPivot(virConnectPtr conn,
}
disk->mirror = NULL;
disk->mirroring = false;
disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_NONE;
cleanup:
/* revert to original disk def on failure */
@ -15091,7 +15091,7 @@ qemuDomainBlockJobImpl(virDomainObjPtr vm,
* avoid checking if pivot is safe. */
if (mode == BLOCK_JOB_INFO && ret == 1 && disk->mirror &&
info->cur == info->end && info->type == VIR_DOMAIN_BLOCK_JOB_TYPE_COPY)
disk->mirroring = true;
disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_READY;
/* A successful block job cancelation stops any mirroring. */
if (mode == BLOCK_JOB_ABORT && disk->mirror) {
@ -15099,7 +15099,7 @@ qemuDomainBlockJobImpl(virDomainObjPtr vm,
* the mirror, and audit that fact, before dropping things. */
virStorageSourceFree(disk->mirror);
disk->mirror = NULL;
disk->mirroring = false;
disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_NONE;
}
waitjob:

4
src/qemu/qemu_process.c
View File

@ -1040,11 +1040,11 @@ qemuProcessHandleBlockJob(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
qemuDomainDetermineDiskChain(driver, vm, disk, true);
if (disk->mirror && type == VIR_DOMAIN_BLOCK_JOB_TYPE_COPY) {
if (status == VIR_DOMAIN_BLOCK_JOB_READY) {
disk->mirroring = true;
disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_READY;
} else if (status == VIR_DOMAIN_BLOCK_JOB_FAILED) {
virStorageSourceFree(disk->mirror);
disk->mirror = NULL;
disk->mirroring = false;
disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_STATE_NONE;
}
}
}

4
tests/qemuxml2argvdata/qemuxml2argv-disk-mirror.xml
View File

@ -42,6 +42,10 @@
<disk type='file' device='disk'>
<source file='/tmp/logs.img'/>
<backingStore/>
<mirror type='file' file='/tmp/logcopy.img' format='qcow2' ready='abort'>
<format type='qcow2'/>
<source file='/tmp/logcopy.img'/>
</mirror>
<target dev='vdb' bus='virtio'/>
</disk>
<controller type='usb' index='0'/>