[libvirt] [PATCHv5 25/28] qemu: snapshot: Improve approach to deal with snapshot metadata
Peter Krempa
pkrempa at redhat.com
Fri Jul 4 11:29:40 UTC 2014
Until now we were changing information about the disk source via
multiple steps of copying data. Now that we changed to a pointer to
store the disk source we might use it to change the approach to track
the data.
Additionally this will allow proper tracking of the backing chain.
---
src/qemu/qemu_driver.c | 122 ++++++++++++++-----------------------------------
1 file changed, 34 insertions(+), 88 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 15c5f3b..e648108 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -12810,14 +12810,11 @@ qemuDomainSnapshotCreateSingleDiskActive(virQEMUDriverPtr driver,
qemuDomainAsyncJob asyncJob)
{
qemuDomainObjPrivatePtr priv = vm->privateData;
+ virStorageSourcePtr newDiskSrc = NULL;
+ virStorageSourcePtr persistDiskSrc = NULL;
char *device = NULL;
char *source = NULL;
- char *newsource = NULL;
- virStorageNetHostDefPtr newhosts = NULL;
- virStorageNetHostDefPtr persistHosts = NULL;
- int format = snap->src->format;
const char *formatStr = NULL;
- char *persistSource = NULL;
int ret = -1;
int fd = -1;
bool need_unlink = false;
@@ -12831,26 +12828,27 @@ qemuDomainSnapshotCreateSingleDiskActive(virQEMUDriverPtr driver,
if (virAsprintf(&device, "drive-%s", disk->info.alias) < 0)
goto cleanup;
- /* XXX Here, we know we are about to alter disk->src->backingStore if
- * successful, so we nuke the existing chain so that future commands will
- * recompute it. Better would be storing the chain ourselves rather than
- * reprobing, but this requires modifying domain_conf and our XML to fully
- * track the chain across libvirtd restarts. */
- virStorageSourceBackingStoreClear(disk->src);
-
if (virStorageFileInit(snap->src) < 0)
goto cleanup;
if (qemuGetDriveSourceString(snap->src, NULL, &source) < 0)
goto cleanup;
- if (VIR_STRDUP(newsource, snap->src->path) < 0)
+ if (!(newDiskSrc = virStorageSourceCopy(snap->src, false)))
goto cleanup;
- if (persistDisk &&
- VIR_STRDUP(persistSource, snap->src->path) < 0)
+ if (virStorageSourceInitChainElement(newDiskSrc, disk->src, false) < 0)
goto cleanup;
+ if (persistDisk) {
+ if (!(persistDiskSrc = virStorageSourceCopy(snap->src, false)))
+ goto cleanup;
+
+ if (virStorageSourceInitChainElement(persistDiskSrc, persistDisk->src,
+ false) < 0)
+ goto cleanup;
+ }
+
switch ((virStorageType)snap->src->type) {
case VIR_STORAGE_TYPE_BLOCK:
case VIR_STORAGE_TYPE_FILE:
@@ -12876,15 +12874,6 @@ qemuDomainSnapshotCreateSingleDiskActive(virQEMUDriverPtr driver,
case VIR_STORAGE_TYPE_NETWORK:
switch (snap->src->protocol) {
case VIR_STORAGE_NET_PROTOCOL_GLUSTER:
- if (!(newhosts = virStorageNetHostDefCopy(snap->src->nhosts,
- snap->src->hosts)))
- goto cleanup;
-
- if (persistDisk &&
- !(persistHosts = virStorageNetHostDefCopy(snap->src->nhosts,
- snap->src->hosts)))
- goto cleanup;
-
break;
default:
@@ -12935,45 +12924,24 @@ qemuDomainSnapshotCreateSingleDiskActive(virQEMUDriverPtr driver,
/* Update vm in place to match changes. */
need_unlink = false;
- VIR_FREE(disk->src->path);
- virStorageNetHostDefFree(disk->src->nhosts, disk->src->hosts);
-
- disk->src->path = newsource;
- disk->src->format = format;
- disk->src->type = snap->src->type;
- disk->src->protocol = snap->src->protocol;
- disk->src->nhosts = snap->src->nhosts;
- disk->src->hosts = newhosts;
-
- newsource = NULL;
- newhosts = NULL;
+ newDiskSrc->backingStore = disk->src;
+ disk->src = newDiskSrc;
+ newDiskSrc = NULL;
if (persistDisk) {
- VIR_FREE(persistDisk->src->path);
- virStorageNetHostDefFree(persistDisk->src->nhosts,
- persistDisk->src->hosts);
-
- persistDisk->src->path = persistSource;
- persistDisk->src->format = format;
- persistDisk->src->type = snap->src->type;
- persistDisk->src->protocol = snap->src->protocol;
- persistDisk->src->nhosts = snap->src->nhosts;
- persistDisk->src->hosts = persistHosts;
-
- persistSource = NULL;
- persistHosts = NULL;
+ persistDiskSrc->backingStore = persistDisk->src;
+ persistDisk->src = persistDiskSrc;
+ persistDiskSrc = NULL;
}
cleanup:
if (need_unlink && virStorageFileUnlink(snap->src))
VIR_WARN("unable to unlink just-created %s", source);
virStorageFileDeinit(snap->src);
+ virStorageSourceFree(newDiskSrc);
+ virStorageSourceFree(persistDiskSrc);
VIR_FREE(device);
VIR_FREE(source);
- VIR_FREE(newsource);
- VIR_FREE(persistSource);
- virStorageNetHostDefFree(snap->src->nhosts, newhosts);
- virStorageNetHostDefFree(snap->src->nhosts, persistHosts);
return ret;
}
@@ -12983,21 +12951,15 @@ qemuDomainSnapshotCreateSingleDiskActive(virQEMUDriverPtr driver,
static void
qemuDomainSnapshotUndoSingleDiskActive(virQEMUDriverPtr driver,
virDomainObjPtr vm,
- virDomainDiskDefPtr origdisk,
virDomainDiskDefPtr disk,
virDomainDiskDefPtr persistDisk,
bool need_unlink)
{
- char *source = NULL;
- char *persistSource = NULL;
+ virStorageSourcePtr tmp;
struct stat st;
ignore_value(virStorageFileInit(disk->src));
- if (VIR_STRDUP(source, origdisk->src->path) < 0 ||
- (persistDisk && VIR_STRDUP(persistSource, source) < 0))
- goto cleanup;
-
qemuDomainPrepareDiskChainElement(driver, vm, disk, disk->src,
VIR_DISK_CHAIN_NO_ACCESS);
if (need_unlink &&
@@ -13005,35 +12967,20 @@ qemuDomainSnapshotUndoSingleDiskActive(virQEMUDriverPtr driver,
virStorageFileUnlink(disk->src) < 0)
VIR_WARN("Unable to remove just-created %s", disk->src->path);
- /* Update vm in place to match changes. */
- VIR_FREE(disk->src->path);
- disk->src->path = source;
- source = NULL;
- disk->src->format = origdisk->src->format;
- disk->src->type = origdisk->src->type;
- disk->src->protocol = origdisk->src->protocol;
- virStorageNetHostDefFree(disk->src->nhosts, disk->src->hosts);
- disk->src->nhosts = origdisk->src->nhosts;
- disk->src->hosts = virStorageNetHostDefCopy(origdisk->src->nhosts,
- origdisk->src->hosts);
+ virStorageFileDeinit(disk->src);
+
+ /* Update vm in place to match changes. */
+ tmp = disk->src;
+ disk->src = tmp->backingStore;
+ tmp->backingStore = NULL;
+ virStorageSourceFree(tmp);
+
if (persistDisk) {
- VIR_FREE(persistDisk->src->path);
- persistDisk->src->path = persistSource;
- persistSource = NULL;
- persistDisk->src->format = origdisk->src->format;
- persistDisk->src->type = origdisk->src->type;
- persistDisk->src->protocol = origdisk->src->protocol;
- virStorageNetHostDefFree(persistDisk->src->nhosts,
- persistDisk->src->hosts);
- persistDisk->src->nhosts = origdisk->src->nhosts;
- persistDisk->src->hosts = virStorageNetHostDefCopy(origdisk->src->nhosts,
- origdisk->src->hosts);
+ tmp = persistDisk->src;
+ persistDisk->src = tmp->backingStore;
+ tmp->backingStore = NULL;
+ virStorageSourceFree(tmp);
}
-
- cleanup:
- virStorageFileDeinit(disk->src);
- VIR_FREE(source);
- VIR_FREE(persistSource);
}
/* The domain is expected to be locked and active. */
@@ -13137,7 +13084,6 @@ qemuDomainSnapshotCreateDiskActive(virQEMUDriverPtr driver,
}
qemuDomainSnapshotUndoSingleDiskActive(driver, vm,
- snap->def->dom->disks[i],
vm->def->disks[i],
persistDisk,
need_unlink);
--
1.9.3
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