[libvirt] [PATCH 3/4] qemu_migration: Check size prerequisites
Michal Privoznik
mprivozn at redhat.com
Thu Sep 12 10:15:18 UTC 2013
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 target, size] and check on destination that
this requirement is met and/or take actions to meet it.
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
src/qemu/qemu_migration.c | 286 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 281 insertions(+), 5 deletions(-)
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 69a9013..5080b0a 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -31,6 +31,9 @@
#endif
#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"
@@ -135,6 +138,15 @@ typedef struct _qemuMigrationCookieNBD qemuMigrationCookieNBD;
typedef qemuMigrationCookieNBD *qemuMigrationCookieNBDPtr;
struct _qemuMigrationCookieNBD {
int port; /* on which port does NBD server listen for incoming data */
+
+ /* The list of pairs [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 *target;
+ size_t bytes;
+ } *disk;
};
typedef struct _qemuMigrationCookie qemuMigrationCookie;
@@ -197,6 +209,22 @@ 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].target);
+
+ VIR_FREE(nbd->disk);
+ VIR_FREE(nbd);
+}
+
+
static void qemuMigrationCookieFree(qemuMigrationCookiePtr mig)
{
if (!mig)
@@ -208,12 +236,14 @@ static void qemuMigrationCookieFree(qemuMigrationCookiePtr mig)
if (mig->flags & QEMU_MIGRATION_COOKIE_NETWORK)
qemuMigrationCookieNetworkFree(mig->network);
+ if (mig->flags & QEMU_MIGRATION_COOKIE_NBD)
+ 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);
}
@@ -518,20 +548,58 @@ qemuMigrationCookieAddNetwork(qemuMigrationCookiePtr mig,
static int
qemuMigrationCookieAddNBD(qemuMigrationCookiePtr mig,
- virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
+ virQEMUDriverPtr driver,
virDomainObjPtr vm)
{
qemuDomainObjPrivatePtr priv = vm->privateData;
+ int ret = -1;
+ size_t i;
/* It is not a bug if there already is a NBD data */
if (!mig->nbd &&
VIR_ALLOC(mig->nbd) < 0)
- return -1;
+ return ret;
+
+ /* 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)
+ goto cleanup;
+
+ for (i = 0; i < vm->def->ndisks; i++) {
+ virDomainDiskDefPtr disk = vm->def->disks[i];
+ virDomainBlockInfo info;
+
+ /* Add only non-shared RW disks with source */
+ if (!disk->src || disk->shared || disk->readonly)
+ continue;
+
+ memset(&info, 0, sizeof(info));
+
+ if (qemuDomainGetDiskBlockInfo(driver, vm, disk, &info) < 0)
+ goto cleanup;
+
+ /* Explicitly not checking which formats can be pre-created here,
+ * as we might be talking to newer libvirt which knows more than we
+ * do now in here. Just let the destination libvirt decide. */
+ if (VIR_STRDUP(mig->nbd->disk[mig->nbd->ndisks].target, disk->dst) < 0)
+ goto cleanup;
+
+ mig->nbd->disk[mig->nbd->ndisks].bytes = info.capacity;
+ mig->nbd->ndisks++;
+ }
+ }
mig->nbd->port = priv->nbdPort;
mig->flags |= QEMU_MIGRATION_COOKIE_NBD;
- return 0;
+ ret = 0;
+
+cleanup:
+ if (ret < 0)
+ qemuMigrationCookieNBDFree(mig->nbd);
+
+ return ret;
}
@@ -641,7 +709,16 @@ qemuMigrationCookieXMLFormat(virQEMUDriverPtr 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 target='%s' size='%zu'/>\n",
+ mig->nbd->disk[i].target,
+ mig->nbd->disk[i].bytes);
+ virBufferAddLit(buf, " </nbd>\n");
+ } else {
+ virBufferAddLit(buf, "/>\n");
+ }
}
virBufferAddLit(buf, "</qemu-migration>\n");
@@ -941,6 +1018,44 @@ qemuMigrationCookieXMLParse(qemuMigrationCookiePtr mig,
goto error;
}
VIR_FREE(port);
+
+ 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];
+
+ tmp = virXPathString("string(./@target)", ctxt);
+ if (!tmp) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("Malformed target attribute"));
+ goto error;
+ }
+ mig->nbd->disk[i].target = tmp;
+ /* deliberately don't free @tmp here, as the
+ * cookie has the reference now and it is
+ * responsible for freeing it later */
+
+ 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;
+ }
+ VIR_FREE(port);
}
virObjectUnref(caps);
@@ -1389,6 +1504,163 @@ cleanup:
return;
}
+static int
+qemuMigrationPreCreateStorageRaw(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr disk,
+ size_t bytes)
+{
+ int ret = -1;
+ struct stat sb;
+ int fd = -1;
+ bool need_unlink = false;
+
+ if ((fd = qemuOpenFile(driver, vm, disk->src, O_RDWR | O_CREAT,
+ &need_unlink, NULL)) < 0)
+ goto cleanup;
+
+ if (fstat(fd, &sb) < 0) {
+ virReportSystemError(errno, _("Unable to stat '%s'"), disk->src);
+ goto cleanup;
+ }
+
+ VIR_DEBUG("File '%s' is %zuB big. Required %zuB", disk->src, sb.st_size, bytes);
+ if (sb.st_size != bytes &&
+ posix_fallocate(fd, 0, bytes) < 0) {
+ virReportSystemError(errno, _("Unable to fallocate '%s'"), disk->src);
+ goto cleanup;
+ }
+
+ ret = 0;
+
+cleanup:
+ VIR_FORCE_CLOSE(fd);
+ if (ret < 0 && need_unlink && unlink(disk->src))
+ VIR_WARN("Unable to unlink '%s': %d", disk->src, errno);
+ return ret;
+}
+
+static int
+qemuMigrationPreCreateStorageQCOW(virQEMUDriverPtr driver,
+ virDomainDiskDefPtr disk,
+ int format,
+ size_t bytes)
+{
+ int ret = -1;
+ const char *imgBinary = qemuFindQemuImgBinary(driver);
+ virCommandPtr cmd = NULL;
+ size_t size_arg;
+
+ if (!imgBinary)
+ return ret;
+
+ /* Size in KB */
+ size_arg = VIR_DIV_UP(bytes, 1024);
+
+ cmd = virCommandNewArgList(imgBinary, "create", "-f",
+ virStorageFileFormatTypeToString(format),
+ "-o", "preallocation=metadata",
+ disk->src, NULL);
+
+ virCommandAddArgFormat(cmd, "%zuK", size_arg);
+
+ if (virCommandRun(cmd, NULL) < 0)
+ goto unlink;
+
+ ret = 0;
+
+cleanup:
+ return ret;
+
+unlink:
+ if (unlink(disk->src) < 0)
+ VIR_WARN("Unable to unlink '%s': %d", disk->src, errno);
+ goto cleanup;
+}
+
+static int
+qemuMigrationPreCreateStorage(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ qemuMigrationCookiePtr mig)
+{
+ int ret = -1;
+ size_t i = 0;
+
+ if (!mig->nbd || !mig->nbd->ndisks) {
+ /* nothing to do here */
+ return 0;
+ }
+
+ for (i = 0; i < mig->nbd->ndisks; i++) {
+ virDomainDiskDefPtr disk;
+ int format;
+ size_t bytes;
+ int index;
+
+ index = virDomainDiskIndexByName(vm->def, mig->nbd->disk[i].target, false);
+ if (index < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("No such disk '%s"),
+ mig->nbd->disk[i].target);
+ goto cleanup;
+ }
+
+ disk = vm->def->disks[i];
+ format = disk->format;
+ bytes = mig->nbd->disk[i].bytes;
+
+ VIR_DEBUG("Checking '%s' of %s format for its size (requested %zuB)",
+ disk->src, virStorageFileFormatTypeToString(format), bytes);
+ switch ((enum virStorageFileFormat) format) {
+ /* These below we know how to pre-create. */
+ case VIR_STORAGE_FILE_RAW:
+ if (qemuMigrationPreCreateStorageRaw(driver, vm, disk, bytes) < 0)
+ goto cleanup;
+ break;
+ case VIR_STORAGE_FILE_QCOW:
+ case VIR_STORAGE_FILE_QCOW2:
+ if (qemuMigrationPreCreateStorageQCOW(driver, disk,
+ format, bytes) < 0)
+ goto cleanup;
+ break;
+
+ /* While these we don't know yet. */
+ case VIR_STORAGE_FILE_AUTO_SAFE:
+ case VIR_STORAGE_FILE_AUTO:
+ case VIR_STORAGE_FILE_NONE:
+ case VIR_STORAGE_FILE_DIR:
+ case VIR_STORAGE_FILE_BOCHS:
+ case VIR_STORAGE_FILE_CLOOP:
+ case VIR_STORAGE_FILE_COW:
+ case VIR_STORAGE_FILE_DMG:
+ case VIR_STORAGE_FILE_ISO:
+ case VIR_STORAGE_FILE_QED:
+ case VIR_STORAGE_FILE_VMDK:
+ case VIR_STORAGE_FILE_VPC:
+ case VIR_STORAGE_FILE_FAT:
+ case VIR_STORAGE_FILE_VHD:
+ case VIR_STORAGE_FILE_VDI:
+ case VIR_STORAGE_FILE_LAST:
+ /* Should we error here? As long as user has no control over which
+ * disks are copied (currently there is no way specifying only a
+ * set of disks to copy) we can't error here. What we can do is
+ * leave users with old migration prerequisite: You (users) are
+ * responsible for creating the storage on the destination. */
+ VIR_WARN("Don't know how to pre-create disks of %s type ('%s')",
+ virStorageFileFormatTypeToString(format), disk->src);
+ break;
+ }
+ }
+
+ ret = 0;
+cleanup:
+ /* free from migration data to prevent
+ * infinite sending from src to dst and back */
+ 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
@@ -2305,6 +2577,10 @@ qemuMigrationPrepareAny(virQEMUDriverPtr driver,
QEMU_MIGRATION_COOKIE_NBD)))
goto cleanup;
+ /* pre-create all storage */
+ if (qemuMigrationPreCreateStorage(driver, vm, mig) < 0)
+ goto cleanup;
+
if (qemuMigrationJobStart(driver, vm, QEMU_ASYNC_JOB_MIGRATION_IN) < 0)
goto cleanup;
qemuMigrationJobSetPhase(driver, vm, QEMU_MIGRATION_PHASE_PREPARE);
--
1.8.1.5
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