[libvirt] [PATCH 1/6] storage:dir: .buildVol and .buildVolFrom callbacks for ploop

[Olga Krishtal]

These callbacks let us to create ploop volumes in directory pools.
If a ploop volume was created via buildVol callback, then this volume
is an empty ploop device with DiskDescriptor.xml.
If the volume was created via .buildFrom - then its content is the
same as input volume.

Ploop volume consists of ploop image file and a corresponding
DiskDescriptor.xml file.

Signed-off-by: Olga Krishtal <okrishtal at virtuozzo.com>
---
 src/storage/storage_backend.c    | 100 ++++++++++++++++++++++++++++++++++++++-
 src/storage/storage_backend.h    |   8 ++++
 src/storage/storage_backend_fs.c |   2 +
 3 files changed, 109 insertions(+), 1 deletion(-)

diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index c07b642..d70642e 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -773,6 +773,103 @@ virStorageBackendCreateExecCommand(virStoragePoolObjPtr pool,
     return ret;
 }
 
+/* Set up directory for ploop volume. If function fails,
+ * volume won't be created.
+ */
+
+static int
+virVolCreateDirForPloop(virStoragePoolObjPtr pool ATTRIBUTE_UNUSED,
+                        virStorageVolDefPtr vol)
+{
+    int err;
+    if ((err = virDirCreate(vol->target.path,
+                            (vol->target.perms->mode == (mode_t) -1 ?
+                             VIR_STORAGE_DEFAULT_VOL_PERM_MODE:
+                             vol->target.perms->mode),
+                             vol->target.perms->uid,
+                             vol->target.perms->gid,
+                             0)) < 0) {
+        return -1;
+    }
+    return 0;
+}
+
+int virStorageBackendCreatePloop(virConnectPtr conn ATTRIBUTE_UNUSED,
+                                 virStoragePoolObjPtr pool,
+                                 virStorageVolDefPtr vol,
+                                 virStorageVolDefPtr inputvol,
+                                 unsigned int flags)
+{
+    int ret = -1;
+    char *size = NULL;
+    char *path = NULL;
+    virCommandPtr cmd = NULL;
+    char *create_tool = NULL;
+
+    virCheckFlags(0, -1);
+
+    create_tool = virFindFileInPath("ploop");
+    if (!create_tool && !inputvol) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       "%s", _("unable to find ploop, please install "
+                        "ploop tools"));
+        return -1;
+    }
+
+    if (inputvol && inputvol->target.format != VIR_STORAGE_FILE_PLOOP) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("unsupported input storage vol type %d"),
+                       inputvol->target.format);
+        return -1;
+    }
+
+    if (vol->target.encryption != NULL) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("encrypted ploop volumes are not supported with "
+                         "ploop init"));
+        return -1;
+    }
+
+    if (vol->target.backingStore != NULL) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("copy-on-write ploop volumes are not yet supported"));
+        return -1;
+    }
+
+    if (!inputvol) {
+        if (virVolCreateDirForPloop(pool, vol) < 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                    "%s", _("error creating directory for ploop volume"));
+            return -1;
+        }
+        if (virAsprintf(&path, "%s/root.hds", vol->target.path) < 0)
+            return -1;
+
+        if (virAsprintf(&size, "%lluM", VIR_DIV_UP(vol->target.capacity,
+                        (1024 * 1024))) < 0) {
+            goto cleanup;
+        }
+
+        cmd = virCommandNewArgList(create_tool, "init", "-s", size, "-t",
+                                   "ext4", path, NULL);
+    } else {
+        vol->target.capacity = inputvol->target.capacity;
+        cmd = virCommandNewArgList("cp", "-r", inputvol->target.path,
+                                   vol->target.path, NULL);
+    }
+    ret = virCommandRun(cmd, NULL);
+    if (ret < 0)
+        virFileDeleteTree(vol->target.path);
+
+ cleanup:
+
+    virCommandFree(cmd);
+    VIR_FREE(size);
+    VIR_FREE(path);
+    VIR_FREE(create_tool);
+    return ret;
+}
+
 enum {
     QEMU_IMG_BACKING_FORMAT_NONE = 0,
     QEMU_IMG_BACKING_FORMAT_FLAG,
@@ -1280,7 +1377,8 @@ virStorageBackendGetBuildVolFromFunction(virStorageVolDefPtr vol,
          vol->target.format != VIR_STORAGE_FILE_RAW) ||
         (inputvol->type == VIR_STORAGE_VOL_FILE &&
          inputvol->target.format != VIR_STORAGE_FILE_RAW)) {
-
+        if (vol->target.format == VIR_STORAGE_FILE_PLOOP)
+            return virStorageBackendCreatePloop;
         if ((tool_type = virStorageBackendFindFSImageTool(NULL)) < 0) {
             virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                            _("creation of non-raw file images is "
diff --git a/src/storage/storage_backend.h b/src/storage/storage_backend.h
index 20e6079..852d6ed 100644
--- a/src/storage/storage_backend.h
+++ b/src/storage/storage_backend.h
@@ -108,6 +108,14 @@ int virStorageBackendCreateRaw(virConnectPtr conn,
                                virStorageVolDefPtr vol,
                                virStorageVolDefPtr inputvol,
                                unsigned int flags);
+
+int virStorageBackendCreatePloop(virConnectPtr conn,
+                                 virStoragePoolObjPtr pool,
+                                 virStorageVolDefPtr vol,
+                                 virStorageVolDefPtr inputvol,
+                                 unsigned int flags);
+
+
 virStorageBackendBuildVolFrom
 virStorageBackendGetBuildVolFromFunction(virStorageVolDefPtr vol,
                                          virStorageVolDefPtr inputvol);
diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
index 692c9ff..80c7e9e 100644
--- a/src/storage/storage_backend_fs.c
+++ b/src/storage/storage_backend_fs.c
@@ -1177,6 +1177,8 @@ _virStorageBackendFileSystemVolBuild(virConnectPtr conn,
         create_func = virStorageBackendCreateRaw;
     } else if (vol->target.format == VIR_STORAGE_FILE_DIR) {
         create_func = createFileDir;
+    } else if (vol->target.format == VIR_STORAGE_FILE_PLOOP) {
+        create_func = virStorageBackendCreatePloop;
     } else if ((tool_type = virStorageBackendFindFSImageTool(NULL)) != -1) {
         create_func = virStorageBackendFSImageToolTypeToFunc(tool_type);
 
-- 
1.8.3.1