add a lxc.rootfs.bdev option (not yet honored)

src/lxc/bdev/bdev.c

@@ -954,3 +954,18 @@ static bool unpriv_snap_allowed(struct bdev *b, const char *t, bool snap,
 		return true;
 	return false;
 }
+
+bool is_valid_bdev_type(const char *type)
+{
+	if (strcmp(type, "dir") == 0 ||
+			strcmp(type, "btrfs") == 0 ||
+			strcmp(type, "aufs") == 0 ||
+			strcmp(type, "loop") == 0 ||
+			strcmp(type, "lvm") == 0 ||
+			strcmp(type, "nbd") == 0 ||
+			strcmp(type, "ovl") == 0 ||
+			strcmp(type, "rbd") == 0 ||
+			strcmp(type, "zfs") == 0)
+		return true;
+	return false;
+}

src/lxc/bdev/bdev.h

@@ -146,4 +146,6 @@ bool rootfs_is_blockdev(struct lxc_conf *conf);
 bool attach_block_device(struct lxc_conf *conf);
 void detach_block_device(struct lxc_conf *conf);
 
+bool is_valid_bdev_type(const char *type);
+
 #endif // __LXC_BDEV_H

src/lxc/conf.c

@@ -4142,6 +4142,7 @@ void lxc_conf_free(struct lxc_conf *conf)
 	free(conf->console.log_path);
 	free(conf->console.path);
 	free(conf->rootfs.mount);
+	free(conf->rootfs.bdev);
 	free(conf->rootfs.options);
 	free(conf->rootfs.path);
 	free(conf->logfile);

src/lxc/conf.h

@@ -220,11 +220,13 @@ struct lxc_console {
  * @path       : the rootfs source (directory or device)
  * @mount      : where it is mounted
  * @options    : mount options
+ * @bev        : optional backing store type
  */
 struct lxc_rootfs {
 	char *path;
 	char *mount;
 	char *options;
+	char *bdev;
 };
 
 /*

src/lxc/confile.c

@@ -42,6 +42,7 @@
 #include "parse.h"
 #include "config.h"
 #include "confile.h"
+#include "bdev/bdev.h"
 #include "utils.h"
 #include "log.h"
 #include "conf.h"
@@ -72,6 +73,7 @@ static int config_fstab(const char *, const char *, struct lxc_conf *);
 static int config_rootfs(const char *, const char *, struct lxc_conf *);
 static int config_rootfs_mount(const char *, const char *, struct lxc_conf *);
 static int config_rootfs_options(const char *, const char *, struct lxc_conf *);
+static int config_rootfs_bdev(const char *, const char *, struct lxc_conf *);
 static int config_pivotdir(const char *, const char *, struct lxc_conf *);
 static int config_utsname(const char *, const char *, struct lxc_conf *);
 static int config_hook(const char *, const char *, struct lxc_conf *lxc_conf);
@@ -130,6 +132,7 @@ static struct lxc_config_t config[] = {
 	{ "lxc.mount",                config_fstab                },
 	{ "lxc.rootfs.mount",         config_rootfs_mount         },
 	{ "lxc.rootfs.options",       config_rootfs_options       },
+	{ "lxc.rootfs.bdev",          config_rootfs_bdev          },
 	{ "lxc.rootfs",               config_rootfs               },
 	{ "lxc.pivotdir",             config_pivotdir             },
 	{ "lxc.utsname",              config_utsname              },
@@ -1853,6 +1856,17 @@ static int config_rootfs_options(const char *key, const char *value,
 	return config_string_item(&lxc_conf->rootfs.options, value);
 }
 
+static int config_rootfs_bdev(const char *key, const char *value,
+			       struct lxc_conf *lxc_conf)
+{
+	if (!is_valid_bdev_type(value)) {
+		ERROR("Bad bdev type for %s: %s", key, value);
+		return -1;
+	}
+
+	return config_string_item(&lxc_conf->rootfs.bdev, value);
+}
+
 static int config_pivotdir(const char *key, const char *value,
 			   struct lxc_conf *lxc_conf)
 {