[libvirt] [PATCH 6/8] qemu: block: Create helper for creating data for legacy snapshots

[Ján Tomko]

On Tue, Jul 03, 2018 at 02:33:04PM +0200, Peter Krempa wrote:
>With 'transaction' support we don't need to keep around the multipurpose
>code which would create the snapshot if 'transaction' is not supported.
>
>To simplify this add a new helper that just wraps the arguments for
>'blockdev-snapshot-sync' operation in 'transaction' and use it instead
>of qemuBlockSnapshotAddLegacy.
>
>Additionally this allows to format the arguments prior to creating the
>file for simpler cleanup.
>
>Signed-off-by: Peter Krempa <pkrempa at redhat.com>
>---
> src/qemu/qemu_block.c  | 37 +++++++++++++++++++++++++++++++++++++
> src/qemu/qemu_block.h  |  6 ++++++
> src/qemu/qemu_driver.c | 18 +++---------------
> 3 files changed, 46 insertions(+), 15 deletions(-)
>
>diff --git a/src/qemu/qemu_block.c b/src/qemu/qemu_block.c
>index 0ebf2d2aff..db1579ca20 100644
>--- a/src/qemu/qemu_block.c
>+++ b/src/qemu/qemu_block.c
>@@ -19,8 +19,10 @@
> #include <config.h>
>
> #include "qemu_block.h"
>+#include "qemu_command.h"
> #include "qemu_domain.h"
> #include "qemu_alias.h"
>+#include "qemu_monitor_json.h"
>
> #include "viralloc.h"
> #include "virstring.h"
>@@ -1683,3 +1685,38 @@ qemuBlockStorageSourceDetachOneBlockdev(virQEMUDriverPtr driver,
>
>     return ret;
> }
>+
>+
>+int
>+qemuBlockSnapshotAddLegacy(virJSONValuePtr actions,
>+                           virDomainDiskDefPtr disk,
>+                           virStorageSourcePtr newsrc,
>+                           bool reuse)
>+{
>+    const char *format = virStorageFileFormatTypeToString(newsrc->format);
>+    char *device = NULL;
>+    char *source = NULL;
>+    int ret = -1;
>+
>+    if (!(device = qemuAliasDiskDriveFromDisk(disk)))
>+        goto cleanup;
>+
>+    if (qemuGetDriveSourceString(newsrc, NULL, &source) < 0)
>+        goto cleanup;
>+
>+    if (qemuMonitorJSONTransactionAdd(actions, "blockdev-snapshot-sync",
>+                                      "s:device", device,
>+                                      "s:snapshot-file", source,
>+                                      "s:format", format,
>+                                      "S:mode", reuse ? "existing" : NULL,
>+                                       NULL) < 0)

Indentation is off.

>+        goto cleanup;
>+
>+    ret = 0;
>+
>+ cleanup:
>+    VIR_FREE(device);
>+    VIR_FREE(source);
>+
>+    return ret;
>+}
>diff --git a/src/qemu/qemu_block.h b/src/qemu/qemu_block.h
>index 418b5064b5..fd8984e60b 100644
>--- a/src/qemu/qemu_block.h
>+++ b/src/qemu/qemu_block.h
>@@ -117,4 +117,10 @@ qemuBlockStorageSourceDetachOneBlockdev(virQEMUDriverPtr driver,
>                                         qemuDomainAsyncJob asyncJob,
>                                         virStorageSourcePtr src);
>
>+int
>+qemuBlockSnapshotAddLegacy(virJSONValuePtr actions,
>+                           virDomainDiskDefPtr disk,
>+                           virStorageSourcePtr newsrc,
>+                           bool reuse);
>+
> #endif /* __QEMU_BLOCK_H__ */
>diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
>index ea06e23ff1..2d8af5daaa 100644
>--- a/src/qemu/qemu_driver.c
>+++ b/src/qemu/qemu_driver.c
>@@ -14932,23 +14932,16 @@ qemuDomainSnapshotCreateSingleDiskActive(virQEMUDriverPtr driver,
>                                          virJSONValuePtr actions,
>                                          bool reuse)
> {
>-    qemuDomainObjPrivatePtr priv = vm->privateData;
>-    char *device = NULL;
>-    char *source = NULL;
>-    const char *formatStr = NULL;
>     int ret = -1;
>
>-    if (!(device = qemuAliasDiskDriveFromDisk(dd->disk)))
>-        goto cleanup;
>-
>-    if (qemuGetDriveSourceString(dd->src, NULL, &source) < 0)
>+    if (qemuBlockSnapshotAddLegacy(actions, dd->disk, dd->src, reuse) < 0)
>         goto cleanup;
>
>     /* pre-create the image file so that we can label it before handing it to qemu */
>     if (!reuse && dd->src->type != VIR_STORAGE_TYPE_BLOCK) {
>         if (virStorageFileCreate(dd->src) < 0) {
>             virReportSystemError(errno, _("failed to create image file '%s'"),
>-                                 source);
>+                                 NULLSTR(dd->src->path));

Doesn't this make the error message less usable?

>             goto cleanup;
>         }
>         dd->created = true;

Reviewed-by: Ján Tomko <jtomko at redhat.com>

Jano
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