Re: [libvirt] [PATCH v5 1/4] 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; and 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 (virDomainDiskMirror): 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(a)redhat.com&gt; --- docs/formatdomain.html.in | 10 +++++++--- docs/schemas/domaincommon.rng | 6 +++++- src/conf/domain_conf.c | 23 +++++++++++++++++++--- src/conf/domain_conf.h | 13 +++++++++++- src/qemu/qemu_driver.c | 12 +++++------ src/qemu/qemu_process.c | 4 ++-- .../qemuxml2argvdata/qemuxml2argv-disk-mirror.xml | 4 ++++ 7 files changed, 56 insertions(+), 16 deletions(-)

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng index f6f697c..389c8c9 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -4284,7 +4284,11 @@ </choice> <optional> <attribute name='ready'> - <value>yes</value> + <choice> + <value>yes</value> + <value>abort</value>

+ <value>pivot</value> + </choice> </attribute> </optional> </element> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 910f6e2..1c8f8cf 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -747,6 +747,12 @@ VIR_ENUM_IMPL(virDomainDiskDiscard, VIR_DOMAIN_DISK_DISCARD_LAST, "unmap", "ignore") +VIR_ENUM_IMPL(virDomainDiskMirror, VIR_DOMAIN_DISK_MIRROR_LAST, + "default", + "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; + def->mirrorState = virDomainDiskMirrorTypeFromString(ready); + if (def->mirrorState < 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")) { @@ -15273,8 +15286,12 @@ 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 = virDomainDiskMirrorTypeToString(def->mirrorState); + virBufferEscapeString(buf, " ready='%s'", mirror); + } virBufferAddLit(buf, ">\n"); virBufferAdjustIndent(buf, 2); virBufferEscapeString(buf, "<format type='%s'/>\n", formatStr); diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index b988b17..bc8966d 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -610,6 +610,16 @@ struct _virDomainBlockIoTuneInfo { typedef virDomainBlockIoTuneInfo *virDomainBlockIoTuneInfoPtr; +typedef enum { + VIR_DOMAIN_DISK_MIRROR_DEFAULT = 0, /* No job, or job still not synced */

+ VIR_DOMAIN_DISK_MIRROR_READY, /* Job in second phase */ + VIR_DOMAIN_DISK_MIRROR_ABORT, /* Job aborted, waiting for event */ + VIR_DOMAIN_DISK_MIRROR_PIVOT, /* Job pivoted, waiting for event */ + + VIR_DOMAIN_DISK_MIRROR_LAST +} virDomainDiskMirror;

+ + /* 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 virDomainDiskMirror */ struct { unsigned int cylinders;

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 704ba39..acc9ef0 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -14846,7 +14846,7 @@ 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); @@ -14860,10 +14860,10 @@ 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_READY; } - if (!disk->mirroring) { + if (disk->mirrorState != VIR_DOMAIN_DISK_MIRROR_READY) { virReportError(VIR_ERR_BLOCK_COPY_ACTIVE, _("disk '%s' not ready for pivot yet"), disk->dst); @@ -14939,7 +14939,7 @@ qemuDomainBlockPivot(virConnectPtr conn, } disk->mirror = NULL; - disk->mirroring = false; + disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_DEFAULT; cleanup: /* revert to original disk def on failure */ @@ -15096,7 +15096,7 @@ 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_READY; /* A successful block job cancelation stops any mirroring. */ if (mode == BLOCK_JOB_ABORT && disk->mirror) { @@ -15104,7 +15104,7 @@ 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_DEFAULT; } waitjob: diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 3d10732..73ad27d 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -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_READY; } else if (status == VIR_DOMAIN_BLOCK_JOB_FAILED) { virStorageSourceFree(disk->mirror); disk->mirror = NULL; - disk->mirroring = false; + disk->mirrorState = VIR_DOMAIN_DISK_MIRROR_DEFAULT; } } } diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-mirror.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-mirror.xml index 72b03c9..fa7af31 100644 --- a/tests/qemuxml2argvdata/qemuxml2argv-disk-mirror.xml +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-mirror.xml @@ -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'/>