storage: rework lvm backend

src/lxc/bdev/bdev.c

@@ -138,8 +138,8 @@ static const struct bdev_ops lvm_ops = {
     .clone_paths = &lvm_clonepaths,
     .destroy = &lvm_destroy,
     .create = &lvm_create,
-    .create_clone = NULL,
-    .create_snapshot = NULL,
+    .create_clone = &lvm_create_clone,
+    .create_snapshot = &lvm_create_snapshot,
     .can_snapshot = true,
     .can_backup = false,
 };
@@ -444,6 +444,19 @@ struct bdev *bdev_copy(struct lxc_container *c0, const char *cname,
 		return new;
 	}
 
+	if (!strcmp(orig->type, "lvm") && !strcmp(new->type, "lvm")) {
+		bool bret = false;
+		if (snap)
+			bret = new->ops->create_snapshot(c0->lxc_conf, orig,
+							 new, newsize);
+		else
+			bret = new->ops->create_clone(c0->lxc_conf, orig, new,
+						      newsize);
+		if (!bret)
+			return NULL;
+		return new;
+	}
+
 	if (strcmp(bdevtype, "btrfs")) {
 		if (!strcmp(new->type, "overlay") ||
 		    !strcmp(new->type, "overlayfs"))

src/lxc/bdev/lxclvm.h

@@ -25,6 +25,7 @@
 #define __LXC_LVM_H
 
 #define _GNU_SOURCE
+#include <stdbool.h>
 #include <stdint.h>
 
 /* defined in bdev.h */
@@ -52,5 +53,9 @@ int lvm_clonepaths(struct bdev *orig, struct bdev *new, const char *oldname,
 int lvm_destroy(struct bdev *orig);
 int lvm_create(struct bdev *bdev, const char *dest, const char *n,
 		struct bdev_specs *specs);
+bool lvm_create_clone(struct lxc_conf *conf, struct bdev *orig,
+		      struct bdev *new, uint64_t newsize);
+bool lvm_create_snapshot(struct lxc_conf *conf, struct bdev *orig,
+			 struct bdev *new, uint64_t newsize);
 
 #endif /* __LXC_LVM_H */