On Thu, Apr 03, 2014 at 11:39:29AM -0400, Tomoki Sekiyama wrote: Are all guests OS required to support unfreeze on a per disk basis. I vaguely recall someone mentioning that some OS can do all-or-none only. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|

Adds 'quiesced' counter into qemuDomainObjPrivate that tracks how many times fsfreeze is requested in the domain. When qemuDomainSnapshotFSFreeze is called, the counter is incremented. The fsfreeze request is sent to the guest agent when the counter changes from 0 to 1. qemuDomainSnapshotFSThaw decrements the counter and requests fsthaw when it becomes 0. It also modify error code from qemuDomainSnapshotFSFreeze and qemuDomainSnapshotFSThaw, so that a caller can know whether the command is actually sent to the guest agent. If the error is caused before sending a freeze command, a counterpart thaw command shouldn't be sent either. Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama(a)hds.com&gt; --- src/qemu/qemu_domain.c | 6 ++++ src/qemu/qemu_domain.h | 2 + src/qemu/qemu_driver.c | 65 ++++++++++++++++++++++++++++++++++++++---------- 3 files changed, 59 insertions(+), 14 deletions(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index cdd4601..6ed3d67 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -357,6 +357,9 @@ qemuDomainObjPrivateXMLFormat(virBufferPtr buf, void *data) virBufferAddLit(buf, "</devices>\n"); } + if (priv->quiesced) + virBufferAsprintf(buf, "<quiesced depth='%d'/>\n", priv->quiesced); + return 0; } @@ -518,6 +521,9 @@ qemuDomainObjPrivateXMLParse(xmlXPathContextPtr ctxt, void *data) } VIR_FREE(nodes); + if (virXPathInt("string(./quiesced/@depth)", ctxt, &priv->quiesced) < 0) + priv->quiesced = 0; + return 0; error: diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index b2830c4..620a258 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -176,6 +176,8 @@ struct _qemuDomainObjPrivate { char **qemuDevices; /* NULL-terminated list of devices aliases known to QEMU */ bool hookRun; /* true if there was a hook run over this domain */ + + int quiesced; /* count how many times filesystems are quiesced */ }; typedef enum { diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 9a2de12..2bb5fa9 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -12100,32 +12100,68 @@ qemuDomainPrepareDiskChainElement(virQEMUDriverPtr driver, } +/* Return -1 if request is not sent to agent due to misconfig, -2 if request + * is sent but failed, and number of frozen filesystems on success. */ static int -qemuDomainSnapshotFSFreeze(virDomainObjPtr vm) +qemuDomainSnapshotFSFreeze(virQEMUDriverPtr driver, virDomainObjPtr vm) { qemuDomainObjPrivatePtr priv = vm->privateData; + virQEMUDriverConfigPtr cfg; int freezed; if (!qemuDomainAgentAvailable(priv, true)) return -1; + priv->quiesced++; + cfg = virQEMUDriverGetConfig(driver); + if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0) { + virObjectUnref(cfg); + priv->quiesced--; + return -1; + } + virObjectUnref(cfg); + + if (priv->quiesced > 1) + return 0; + qemuDomainObjEnterAgent(vm); freezed = qemuAgentFSFreeze(priv->agent); qemuDomainObjExitAgent(vm); - - return freezed; + return freezed < 0 ? -2 : freezed; } +/* Return -1 if request is not sent to agent due to misconfig, -2 if request + * is sent but failed, and number of thawed filesystems on success. */ static int -qemuDomainSnapshotFSThaw(virDomainObjPtr vm, bool report) +qemuDomainSnapshotFSThaw(virQEMUDriverPtr driver, + virDomainObjPtr vm, bool report) { qemuDomainObjPrivatePtr priv = vm->privateData; + virQEMUDriverConfigPtr cfg; int thawed; virErrorPtr err = NULL; if (!qemuDomainAgentAvailable(priv, report)) return -1; + if (!priv->quiesced && report) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("domain is not quiesced")); + return -1; + } + + priv->quiesced--; + cfg = virQEMUDriverGetConfig(driver); + if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0) { + virObjectUnref(cfg); + priv->quiesced++; + return -1; + } + virObjectUnref(cfg); + + if (priv->quiesced) + return 0; + qemuDomainObjEnterAgent(vm); if (!report) err = virSaveLastError(); @@ -12135,7 +12171,7 @@ qemuDomainSnapshotFSThaw(virDomainObjPtr vm, bool report) qemuDomainObjExitAgent(vm); virFreeError(err); - return thawed; + return thawed < 0 ? -2 : thawed; } /* The domain is expected to be locked and inactive. */ @@ -13116,17 +13152,18 @@ qemuDomainSnapshotCreateActiveExternal(virConnectPtr conn, goto cleanup; /* If quiesce was requested, then issue a freeze command, and a - * counterpart thaw command, no matter what. The command will - * fail if the guest is paused or the guest agent is not - * running. */ + * counterpart thaw command when it is actually sent to agent. + * The command will fail if the guest is paused or the guest agent + * is not running, or is already quiesced. */ if (flags & VIR_DOMAIN_SNAPSHOT_CREATE_QUIESCE) { - if (qemuDomainSnapshotFSFreeze(vm) < 0) { - /* helper reported the error */ - thaw = -1; + int freeze = qemuDomainSnapshotFSFreeze(driver, vm); + if (freeze < 0) { + /* the helper reported the error */ + if (freeze == -2) + thaw = -1; /* the command is sent but agent failed */ goto endjob; - } else { - thaw = 1; } + thaw = 1; } /* We need to track what state the guest is in, since taking the @@ -13267,7 +13304,7 @@ qemuDomainSnapshotCreateActiveExternal(virConnectPtr conn, goto cleanup; } if (vm && thaw != 0 && - qemuDomainSnapshotFSThaw(vm, thaw > 0) < 0) { + qemuDomainSnapshotFSThaw(driver, vm, thaw > 0) < 0) { /* helper reported the error, if it was needed */ if (thaw > 0) ret = -1;

These are exposed under domfsfreeze command and domfsthaw command. Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama(a)hds.com&gt; --- tools/virsh-domain.c | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++ tools/virsh.pod | 23 +++++++++ 2 files changed, 151 insertions(+) diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c index 73414f8..331ba36 100644 --- a/tools/virsh-domain.c +++ b/tools/virsh-domain.c @@ -11391,6 +11391,122 @@ cmdDomFSTrim(vshControl *ctl, const vshCmd *cmd) return ret; } +static const vshCmdInfo info_domfsfreeze[] = { + {.name = "help", + .data = N_("Freeze domain's mounted filesystems.") + }, + {.name = "desc", + .data = N_("Freeze domain's mounted filesystems.") + }, + {.name = NULL} +}; + +static const vshCmdOptDef opts_domfsfreeze[] = { + {.name = "domain", + .type = VSH_OT_DATA, + .flags = VSH_OFLAG_REQ, + .help = N_("domain name, id or uuid") + }, + {.name = "disks", + .type = VSH_OT_DATA, + .help = N_("comma separated list of disks to be frozen") + }, + {.name = NULL} +}; +static bool +cmdDomFSFreeze(vshControl *ctl, const vshCmd *cmd) +{ + virDomainPtr dom = NULL; + bool ret = false; + unsigned int flags = 0; + const char *disk_string = NULL; + char **disk_list = NULL; /* tokenized disk_string */ + int ndisks = 0; + size_t i; + + ignore_value(vshCommandOptString(cmd, "disks", &disk_string)); + + if (!(dom = vshCommandOptDomain(ctl, cmd, NULL))) + return ret; + + if (disk_string) { + if ((ndisks = vshStringToArray(disk_string, &disk_list)) < 0) + goto cleanup; + } + + if (virDomainFSFreeze(dom, (const char **)disk_list, ndisks, flags) < 0) { + vshError(ctl, _("Unable to freeze filesystems")); + goto cleanup; + } + + ret = true; + + cleanup: + for (i = 0; i < ndisks; i++) + VIR_FREE(disk_list[i]); + VIR_FREE(disk_list); + virDomainFree(dom); + return ret; +} + +static const vshCmdInfo info_domfsthaw[] = { + {.name = "help", + .data = N_("Thaw domain's mounted filesystems.") + }, + {.name = "desc", + .data = N_("Thaw domain's mounted filesystems.") + }, + {.name = NULL} +}; + +static const vshCmdOptDef opts_domfsthaw[] = { + {.name = "domain", + .type = VSH_OT_DATA, + .flags = VSH_OFLAG_REQ, + .help = N_("domain name, id or uuid") + }, + {.name = "disks", + .type = VSH_OT_DATA, + .help = N_("comma separated list of disks to be thawed") + }, + {.name = NULL} +}; +static bool +cmdDomFSThaw(vshControl *ctl, const vshCmd *cmd) +{ + virDomainPtr dom = NULL; + bool ret = false; + unsigned int flags = 0; + const char *disk_string = NULL; + char **disk_list = NULL; /* tokenized disk_string */ + int ndisks = 0; + size_t i; + + ignore_value(vshCommandOptString(cmd, "disks", &disk_string)); + + if (!(dom = vshCommandOptDomain(ctl, cmd, NULL))) + return ret; + + if (disk_string) { + if ((ndisks = vshStringToArray(disk_string, &disk_list)) < 0) + goto cleanup; + } + + if (virDomainFSThaw(dom, (const char **)disk_list, ndisks, flags) < 0) { + vshError(ctl, _("Unable to thaw filesystems")); + goto cleanup; + } + + ret = true; + + cleanup: + for (i = 0; i < ndisks; i++) + VIR_FREE(disk_list[i]); + VIR_FREE(disk_list); + virDomainFree(dom); + return ret; +} + const vshCmdDef domManagementCmds[] = { {.name = "attach-device", .handler = cmdAttachDevice, @@ -11538,6 +11654,18 @@ const vshCmdDef domManagementCmds[] = { .info = info_domdisplay, .flags = 0 }, + {.name = "domfsfreeze", + .handler = cmdDomFSFreeze, + .opts = opts_domfsfreeze, + .info = info_domfsfreeze, + .flags = 0 + }, + {.name = "domfsthaw", + .handler = cmdDomFSThaw, + .opts = opts_domfsthaw, + .info = info_domfsthaw, + .flags = 0 + }, {.name = "domfstrim", .handler = cmdDomFSTrim, .opts = opts_domfstrim, diff --git a/tools/virsh.pod b/tools/virsh.pod index 98d891a..652aabc 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -941,6 +941,29 @@ Output a URI which can be used to connect to the graphical display of the domain via VNC, SPICE or RDP. If I<--include-password> is specified, the SPICE channel password will be included in the URI. +=item B<domfsfreeze> I<domain> [I<--disks> B<disks>] + +Freeze all mounted filesystems within a running domain to prepare for +consistent snapshots. + +The I<--disks> flag takes a parameter B<disks>, which is a comma separated +list of names of disks to be frozen. If this is not specified, every mounted +filesystem on the guest is frozen. + +Note that B<snapshot-create> command has a I<--quiesce> option to freeze +and thaw the filesystems automatically to keep snapshots consistent. +B<domfsfreeze> command is only needed when a user wants to utilize the +native snapshot features of storage devices not supported by libvirt yet. + +=item B<domfsthaw> I<domain> [I<--disks> B<disks>] + +Thaw all mounted filesystems within a running domain, which are frozen +by domfsfreeze command. + +The I<--disks> flag takes a parameter B<disks>, which is a comma separated +list of names of disks to be thawed. If this is not specified, every mounted +filesystem on the guest is thawed. + =item B<domfstrim> I<domain> [I<--minimum> B<bytes>] [I<--mountpoint mountPoint>]