initialize "meta" in virStorageFileGetMetadata, not in each caller

Do not require each caller of virStorageFileGetMetadata and
virStorageFileGetMetadataFromFD to first clear the storage of the
"meta" buffer.  Instead, initialize that storage in
virStorageFileGetMetadataFromFD.
* src/util/storage_file.c (virStorageFileGetMetadataFromFD): Clear
"meta" here, not before each of the following callers.
* src/qemu/qemu_driver.c (qemuSetupDiskCgroup): Don't clear "meta" here.
(qemuTeardownDiskCgroup): Likewise.
* src/qemu/qemu_security_dac.c (qemuSecurityDACSetSecurityImageLabel):
Likewise.
* src/security/security_selinux.c (SELinuxSetSecurityImageLabel):
Likewise.
* src/security/virt-aa-helper.c (get_files): Likewise.

src/qemu/qemu_driver.c

@@ -2982,8 +2982,6 @@ static int qemuSetupDiskCgroup(virCgroupPtr cgroup,
             }
         }
 
-        memset(&meta, 0, sizeof(meta));
-
         rc = virStorageFileGetMetadata(path, &meta);
 
         if (path != disk->src)
@@ -3030,8 +3028,6 @@ static int qemuTeardownDiskCgroup(virCgroupPtr cgroup,
             }
         }
 
-        memset(&meta, 0, sizeof(meta));
-
         rc = virStorageFileGetMetadata(path, &meta);
 
         if (path != disk->src)
@@ -9386,7 +9382,6 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,
     }
 
     /* Probe for magic formats */
-    memset(&meta, 0, sizeof(meta));
     if (virStorageFileGetMetadataFromFD(path, fd, &meta) < 0)
         goto cleanup;
 

src/qemu/qemu_security_dac.c

@@ -115,8 +115,6 @@ qemuSecurityDACSetSecurityImageLabel(virDomainObjPtr vm ATTRIBUTE_UNUSED,
         virStorageFileMetadata meta;
         int ret;
 
-        memset(&meta, 0, sizeof(meta));
-
         ret = virStorageFileGetMetadata(path, &meta);
 
         if (path != disk->src)

src/security/security_selinux.c

@@ -454,8 +454,6 @@ SELinuxSetSecurityImageLabel(virDomainObjPtr vm,
         virStorageFileMetadata meta;
         int ret;
 
-        memset(&meta, 0, sizeof(meta));
-
         ret = virStorageFileGetMetadata(path, &meta);
 
         if (path != disk->src)

src/security/virt-aa-helper.c

@@ -830,8 +830,6 @@ get_files(vahControl * ctl)
             do {
                 virStorageFileMetadata meta;
 
-                memset(&meta, 0, sizeof(meta));
-
                 ret = virStorageFileGetMetadata(path, &meta);
 
                 if (path != ctl->def->disks[i]->src)

src/util/storage_file.c

@@ -275,6 +275,8 @@ virStorageFileGetMetadataFromFD(const char *path,
     unsigned char head[20*512]; /* vmdk4GetBackingStore needs this much. */
     int len, i;
 
+    memset(meta, 0, sizeof (*meta));
+
     /* If all else fails, call it a raw file */
     meta->format = VIR_STORAGE_FILE_RAW;