With new NBD storage migration approach there are several requirements that need to be meet for successful use of the feature. One of them is - the file representing a disk, needs to have at least same size as on the source. Hence, we must transfer a list of pairs [disk source, size] and check on destination that this requirement is met and/or take actions to meet it. --- src/qemu/qemu_migration.c | 162 ++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 159 insertions(+), 3 deletions(-) diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index 2c66d8c..f8e52fb 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -27,6 +27,9 @@ #include <gnutls/x509.h> #include <fcntl.h> #include <poll.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> #include "qemu_migration.h" #include "qemu_monitor.h" @@ -131,6 +134,15 @@ struct _qemuMigrationCookieNBD { Negative one is meant to be sent when translating from perform to finish phase to let destination know it's safe to stop NBD server.*/ + + /* The list of pairs [disk-alias,disk-size] (in Bytes). + * This is needed because the same disk size is one of + * prerequisites for NBD storage migration. */ + size_t ndisks; + struct { + char *src; /* disk alias */ + size_t bytes; + } *disk; }; typedef struct _qemuMigrationCookie qemuMigrationCookie; @@ -193,6 +205,21 @@ qemuMigrationCookieNetworkFree(qemuMigrationCookieNetworkPtr network) } +static void +qemuMigrationCookieNBDFree(qemuMigrationCookieNBDPtr nbd) +{ + size_t i; + + if (!nbd) + return; + + for (i = 0; i < nbd->ndisks; i++) + VIR_FREE(nbd->disk[i].src); + VIR_FREE(nbd->disk); + VIR_FREE(nbd); +} + + static void qemuMigrationCookieFree(qemuMigrationCookiePtr mig) { if (!mig) @@ -204,12 +231,13 @@ static void qemuMigrationCookieFree(qemuMigrationCookiePtr mig) if (mig->flags & QEMU_MIGRATION_COOKIE_NETWORK) qemuMigrationCookieNetworkFree(mig->network); + qemuMigrationCookieNBDFree(mig->nbd); + VIR_FREE(mig->localHostname); VIR_FREE(mig->remoteHostname); VIR_FREE(mig->name); VIR_FREE(mig->lockState); VIR_FREE(mig->lockDriver); - VIR_FREE(mig->nbd); VIR_FREE(mig); } @@ -512,8 +540,12 @@ qemuMigrationCookieAddNetwork(qemuMigrationCookiePtr mig, static int qemuMigrationCookieAddNBD(qemuMigrationCookiePtr mig, + virDomainObjPtr vm, int nbdPort) { + qemuDomainObjPrivatePtr priv = vm->privateData; + size_t i; + /* It is not a bug if there already is a NBD data */ if (!mig->nbd && VIR_ALLOC(mig->nbd) < 0) { @@ -521,6 +553,38 @@ qemuMigrationCookieAddNBD(qemuMigrationCookiePtr mig, return -1; } + /* in Begin phase add info about disks */ + if (priv->job.phase == QEMU_MIGRATION_PHASE_BEGIN3 && + vm->def->ndisks) { + if (VIR_ALLOC_N(mig->nbd->disk, vm->def->ndisks) < 0) { + virReportOOMError(); + return -1; + } + + for (i = 0; i < vm->def->ndisks; i++) { + virDomainDiskDefPtr disk = vm->def->disks[i]; + struct stat sb; + + if (!disk->src) + continue; + + if (virAsprintf(&mig->nbd->disk[mig->nbd->ndisks].src, + "%s", disk->src) < 0) { + virReportOOMError(); + return -1; + } + + if (stat(disk->src, &sb) < 0) { + virReportSystemError(errno, + _("Unable to stat '%s'"), + disk->src); + return -1; + } + + mig->nbd->disk[mig->nbd->ndisks++].bytes = sb.st_size; + } + } + mig->nbd->port = nbdPort; mig->flags |= QEMU_MIGRATION_COOKIE_NBD; @@ -634,7 +698,16 @@ qemuMigrationCookieXMLFormat(struct qemud_driver *driver, virBufferAddLit(buf, " <nbd"); if (mig->nbd->port) virBufferAsprintf(buf, " port='%d'", mig->nbd->port); - virBufferAddLit(buf, "/>\n"); + if (mig->nbd->ndisks) { + virBufferAddLit(buf, ">\n"); + for (i = 0; i < mig->nbd->ndisks; i++) + virBufferAsprintf(buf, " <disk src='%s' size='%zu'/>\n", + mig->nbd->disk[i].src, + mig->nbd->disk[i].bytes); + virBufferAddLit(buf, " </nbd>\n"); + } else { + virBufferAddLit(buf, "/>\n"); + } } virBufferAddLit(buf, "</qemu-migration>\n"); @@ -939,6 +1012,34 @@ qemuMigrationCookieXMLParse(qemuMigrationCookiePtr mig, port); goto error; } + + if ((n = virXPathNodeSet("./nbd/disk", ctxt, &nodes)) > 0) { + xmlNodePtr oldNode = ctxt->node; + if (VIR_ALLOC_N(mig->nbd->disk, n) < 0) { + virReportOOMError(); + goto error; + } + mig->nbd->ndisks = n; + + for (i = 0; i < n; i++) { + ctxt->node = nodes[i]; + + mig->nbd->disk[i].src = virXPathString("string(./@src)", ctxt); + + tmp = virXPathString("string(./@size)", ctxt); + if (virStrToLong_ull(tmp, NULL, 10, (unsigned long long *) + &mig->nbd->disk[i].bytes) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Malformed size attribute '%s'"), + tmp); + VIR_FREE(tmp); + goto error; + } + VIR_FREE(tmp); + } + VIR_FREE(nodes); + ctxt->node = oldNode; + } } return 0; @@ -1007,7 +1108,7 @@ qemuMigrationBakeCookie(qemuMigrationCookiePtr mig, } if (flags & QEMU_MIGRATION_COOKIE_NBD && - qemuMigrationCookieAddNBD(mig, nbdPort) < 0) + qemuMigrationCookieAddNBD(mig, dom, nbdPort) < 0) return -1; if (!(*cookieout = qemuMigrationCookieXMLFormatStr(driver, mig))) @@ -1334,6 +1435,57 @@ error: goto cleanup; } +static int +qemuMigrationPreCreateStorage(qemuMigrationCookiePtr mig) +{ + int ret = -1; + size_t i; + struct stat sb; + int fd = -1; + + if (!mig->nbd || !mig->nbd->ndisks) { + /* nothing to do here */ + return 0; + } + + for (i = 0; i < mig->nbd->ndisks; i++) { + const char *src = mig->nbd->disk[i].src; + size_t bytes = mig->nbd->disk[i].bytes; + VIR_DEBUG("Checking '%s' for its size (requested %zuB)", src, bytes); + + if ((fd = virFileOpenAs(src, O_RDWR | O_CREAT, 0660, + -1, -1, VIR_FILE_OPEN_NOFORK)) < 0) { + virReportSystemError(errno, _("Unable to create '%s'"), src); + goto cleanup; + } + + if (fstat(fd, &sb) < 0) { + virReportSystemError(errno, _("Unable to stat '%s'"), src); + goto cleanup; + } + + VIR_DEBUG("File '%s' is %zuB big", src, sb.st_size); + if (sb.st_size < bytes && + ftruncate(fd, bytes) < 0) { + virReportSystemError(errno, _("Unable to ftruncate '%s'"), src); + goto cleanup; + } + + VIR_FORCE_CLOSE(fd); + } + + ret = 0; +cleanup: + VIR_FORCE_CLOSE(fd); + /* free from migration data to prevent + * infinite sending from src to dst and back */ + for (i = 0; i < mig->nbd->ndisks; i++) + VIR_FREE(mig->nbd->disk[i].src); + VIR_FREE(mig->nbd->disk); + mig->nbd->ndisks = 0; + return ret; +} + /* Validate whether the domain is safe to migrate. If vm is NULL, * then this is being run in the v2 Prepare stage on the destination * (where we only have the target xml); if vm is provided, then this @@ -1932,6 +2084,10 @@ qemuMigrationPrepareAny(struct qemud_driver *driver, QEMU_MIGRATION_COOKIE_NBD))) goto cleanup; + /* pre-create all storage */ + if (qemuMigrationPreCreateStorage(mig) < 0) + goto cleanup; + if (qemuMigrationJobStart(driver, vm, QEMU_ASYNC_JOB_MIGRATION_IN) < 0) goto cleanup; qemuMigrationJobSetPhase(driver, vm, QEMU_MIGRATION_PHASE_PREPARE); -- 1.7.8.6 -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list