[libvirt] [PATCH v3 1/2] storage: allow metadata preallocation when creating qcow2 images
Ján Tomko
jtomko at redhat.com
Wed Dec 5 10:48:07 UTC 2012
Add VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA flag to virStorageVolCreateXML
and virStorageVolCreateXMLFrom. This flag requests metadata
preallocation when creating/cloning qcow2 images, resulting in creating
a sparse file with qcow2 metadata. It has only slightly larger disk usage
compared to new image with no allocation, but offers higher performance.
---
include/libvirt/libvirt.h.in | 4 +++
src/libvirt.c | 16 ++++++++++--
src/storage/storage_backend.c | 46 ++++++++++++++++++++++++++-----------
src/storage/storage_backend.h | 3 +-
src/storage/storage_backend_fs.c | 16 ++++++++-----
src/storage/storage_driver.c | 6 ++--
6 files changed, 64 insertions(+), 27 deletions(-)
diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index a19f37a..17804ca 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -2906,6 +2906,10 @@ virStorageVolPtr virStorageVolLookupByPath (virConnectPtr conn,
const char* virStorageVolGetName (virStorageVolPtr vol);
const char* virStorageVolGetKey (virStorageVolPtr vol);
+typedef enum {
+ VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA = 1 << 0,
+} virStorageVolCreateFlags;
+
virStorageVolPtr virStorageVolCreateXML (virStoragePoolPtr pool,
const char *xmldesc,
unsigned int flags);
diff --git a/src/libvirt.c b/src/libvirt.c
index 4b7baab..6a7a817 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -13382,11 +13382,16 @@ virStorageVolGetKey(virStorageVolPtr vol)
* virStorageVolCreateXML:
* @pool: pointer to storage pool
* @xmlDesc: description of volume to create
- * @flags: extra flags; not used yet, so callers should always pass 0
+ * @flags: bitwise-OR of virStorageVolCreateFlags
*
* Create a storage volume within a pool based
* on an XML description. Not all pools support
- * creation of volumes
+ * creation of volumes.
+ *
+ * Since 1.0.1 VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA
+ * in flags can be used to get higher performance with
+ * qcow2 image files which don't support full preallocation,
+ * by creating a sparse image file with metadata.
*
* Returns the storage volume, or NULL on error
*/
@@ -13433,13 +13438,18 @@ error:
* @pool: pointer to parent pool for the new volume
* @xmlDesc: description of volume to create
* @clonevol: storage volume to use as input
- * @flags: extra flags; not used yet, so callers should always pass 0
+ * @flags: bitwise-OR of virStorageVolCreateFlags
*
* Create a storage volume in the parent pool, using the
* 'clonevol' volume as input. Information for the new
* volume (name, perms) are passed via a typical volume
* XML description.
*
+ * Since 1.0.1 VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA
+ * in flags can be used to get higher performance with
+ * qcow2 image files which don't support full preallocation,
+ * by creating a sparse image file with metadata.
+ *
* Returns the storage volume, or NULL on error
*/
virStorageVolPtr
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index 83c4755..083028d 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -668,8 +668,11 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
virCommandPtr cmd = NULL;
bool do_encryption = (vol->target.encryption != NULL);
unsigned long long int size_arg;
+ bool preallocate = false;
- virCheckFlags(0, -1);
+ virCheckFlags(VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA, -1);
+
+ preallocate = !!(flags & VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA);
const char *type = virStorageFileFormatTypeToString(vol->target.format);
const char *backingType = vol->backingStore.path ?
@@ -697,11 +700,23 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
inputvol->target.format);
return -1;
}
+ if (preallocate && vol->target.format != VIR_STORAGE_FILE_QCOW2) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("metadata preallocation only available with qcow2"));
+ return -1;
+ }
if (vol->backingStore.path) {
int accessRetCode = -1;
char *absolutePath = NULL;
+ if (preallocate) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("metadata preallocation conflicts with backing"
+ " store"));
+ return -1;
+ }
+
/* XXX: Not strictly required: qemu-img has an option a different
* backing store, not really sure what use it serves though, and it
* may cause issues with lvm. Untested essentially.
@@ -796,14 +811,15 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
virCommandAddArgList(cmd, "convert", "-f", inputType, "-O", type,
inputPath, vol->target.path, NULL);
- if (do_encryption) {
- if (imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS) {
- virCommandAddArgList(cmd, "-o", "encryption=on", NULL);
- } else {
- virCommandAddArg(cmd, "-e");
- }
+ if (imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS &&
+ (do_encryption || preallocate)) {
+ virCommandAddArg(cmd, "-o");
+ virCommandAddArgFormat(cmd, "%s%s%s", do_encryption ? "encryption=on" : "",
+ (do_encryption && preallocate) ? "," : "",
+ preallocate ? "preallocation=metadata" : "");
+ } else if (do_encryption) {
+ virCommandAddArg(cmd, "-e");
}
-
} else if (vol->backingStore.path) {
virCommandAddArgList(cmd, "create", "-f", type,
"-b", vol->backingStore.path, NULL);
@@ -840,12 +856,14 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
vol->target.path, NULL);
virCommandAddArgFormat(cmd, "%lluK", size_arg);
- if (do_encryption) {
- if (imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS) {
- virCommandAddArgList(cmd, "-o", "encryption=on", NULL);
- } else {
- virCommandAddArg(cmd, "-e");
- }
+ if (imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS &&
+ (do_encryption || preallocate)) {
+ virCommandAddArg(cmd, "-o");
+ virCommandAddArgFormat(cmd, "%s%s%s", do_encryption ? "encryption=on" : "",
+ (do_encryption && preallocate) ? "," : "",
+ preallocate ? "preallocation=metadata" : "");
+ } else if (do_encryption) {
+ virCommandAddArg(cmd, "-e");
}
}
diff --git a/src/storage/storage_backend.h b/src/storage/storage_backend.h
index 29cad9d..c991015 100644
--- a/src/storage/storage_backend.h
+++ b/src/storage/storage_backend.h
@@ -37,7 +37,8 @@ typedef int (*virStorageBackendStopPool)(virConnectPtr conn, virStoragePoolObjPt
typedef int (*virStorageBackendDeletePool)(virConnectPtr conn, virStoragePoolObjPtr pool, unsigned int flags);
typedef int (*virStorageBackendBuildVol)(virConnectPtr conn,
- virStoragePoolObjPtr pool, virStorageVolDefPtr vol);
+ virStoragePoolObjPtr pool, virStorageVolDefPtr vol,
+ unsigned int flags);
typedef int (*virStorageBackendCreateVol)(virConnectPtr conn, virStoragePoolObjPtr pool, virStorageVolDefPtr vol);
typedef int (*virStorageBackendRefreshVol)(virConnectPtr conn, virStoragePoolObjPtr pool, virStorageVolDefPtr vol);
typedef int (*virStorageBackendDeleteVol)(virConnectPtr conn, virStoragePoolObjPtr pool, virStorageVolDefPtr vol, unsigned int flags);
diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
index 4e6ebbf..7a54ead 100644
--- a/src/storage/storage_backend_fs.c
+++ b/src/storage/storage_backend_fs.c
@@ -1045,7 +1045,8 @@ static int
_virStorageBackendFileSystemVolBuild(virConnectPtr conn,
virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
- virStorageVolDefPtr inputvol)
+ virStorageVolDefPtr inputvol,
+ unsigned int flags)
{
virStorageBackendBuildVolFrom create_func;
int tool_type;
@@ -1078,7 +1079,7 @@ _virStorageBackendFileSystemVolBuild(virConnectPtr conn,
return -1;
}
- if (create_func(conn, pool, vol, inputvol, 0) < 0)
+ if (create_func(conn, pool, vol, inputvol, flags) < 0)
return -1;
return 0;
}
@@ -1091,8 +1092,11 @@ _virStorageBackendFileSystemVolBuild(virConnectPtr conn,
static int
virStorageBackendFileSystemVolBuild(virConnectPtr conn,
virStoragePoolObjPtr pool,
- virStorageVolDefPtr vol) {
- return _virStorageBackendFileSystemVolBuild(conn, pool, vol, NULL);
+ virStorageVolDefPtr vol,
+ unsigned int flags) {
+ virCheckFlags(VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA, -1);
+
+ return _virStorageBackendFileSystemVolBuild(conn, pool, vol, NULL, flags);
}
/*
@@ -1105,9 +1109,9 @@ virStorageBackendFileSystemVolBuildFrom(virConnectPtr conn,
virStorageVolDefPtr inputvol,
unsigned int flags)
{
- virCheckFlags(0, -1);
+ virCheckFlags(VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA, -1);
- return _virStorageBackendFileSystemVolBuild(conn, pool, vol, inputvol);
+ return _virStorageBackendFileSystemVolBuild(conn, pool, vol, inputvol, flags);
}
/**
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 3cb2312..c567fff 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -1348,7 +1348,7 @@ storageVolumeCreateXML(virStoragePoolPtr obj,
virStorageVolDefPtr voldef = NULL;
virStorageVolPtr ret = NULL, volobj = NULL;
- virCheckFlags(0, NULL);
+ virCheckFlags(VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA, NULL);
storageDriverLock(driver);
pool = virStoragePoolObjFindByUUID(&driver->pools, obj->uuid);
@@ -1425,7 +1425,7 @@ storageVolumeCreateXML(virStoragePoolPtr obj,
voldef->building = 1;
virStoragePoolObjUnlock(pool);
- buildret = backend->buildVol(obj->conn, pool, buildvoldef);
+ buildret = backend->buildVol(obj->conn, pool, buildvoldef, flags);
storageDriverLock(driver);
virStoragePoolObjLock(pool);
@@ -1473,7 +1473,7 @@ storageVolumeCreateXMLFrom(virStoragePoolPtr obj,
virStorageVolPtr ret = NULL, volobj = NULL;
int buildret;
- virCheckFlags(0, NULL);
+ virCheckFlags(VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA, NULL);
storageDriverLock(driver);
pool = virStoragePoolObjFindByUUID(&driver->pools, obj->uuid);
--
1.7.8.6
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