diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d47ce83078545e747e2567f8b1d3e3407e48aabd..3458b5725540c511103421bf8f1749833c2998f7 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1284,6 +1284,8 @@ struct btrfs_root {
 #define BTRFS_INODE_DIRSYNC		(1 << 10)
 #define BTRFS_INODE_COMPRESS		(1 << 11)
 
+#define BTRFS_INODE_ROOT_ITEM_INIT	(1 << 31)
+
 /* some macros to generate set/get funcs for the struct fields.  This
  * assumes there is a lefoo_to_cpu for every type, so lets make a simple
  * one for u8:
@@ -2359,6 +2361,8 @@ int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid);
 int btrfs_find_orphan_roots(struct btrfs_root *tree_root);
 int btrfs_set_root_node(struct btrfs_root_item *item,
 			struct extent_buffer *node);
+void btrfs_check_and_init_root_item(struct btrfs_root_item *item);
+
 /* dir-item.c */
 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root, const char *name,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5cf3aa7b125c2686304b4bc2ec0449af33566166..a272bfd74ea083f1ee13cde42012dac8d28dc8cc 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1276,8 +1276,10 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
 	root->commit_root = btrfs_root_node(root);
 	BUG_ON(!root->node);
 out:
-	if (location->objectid != BTRFS_TREE_LOG_OBJECTID)
+	if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
 		root->ref_cows = 1;
+		btrfs_check_and_init_root_item(&root->root_item);
+	}
 
 	return root;
 }
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 255c7c5279c4a245f5d401b8b283539895b03d18..f9c93a9ed4a762158df6ae4d494a1b016d10ff5a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -373,6 +373,10 @@ static noinline int create_subvol(struct btrfs_root *root,
 	inode_item->nbytes = cpu_to_le64(root->leafsize);
 	inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 
+	root_item.flags = 0;
+	root_item.byte_limit = 0;
+	inode_item->flags = cpu_to_le64(BTRFS_INODE_ROOT_ITEM_INIT);
+
 	btrfs_set_root_bytenr(&root_item, leaf->start);
 	btrfs_set_root_generation(&root_item, trans->transid);
 	btrfs_set_root_level(&root_item, 0);
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 29b2d7c930eb3f9242e7df8734a1651844285fcf..6928bff62daa8370b4d9efce397fac35208c9611 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -473,3 +473,21 @@ int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
 	btrfs_free_path(path);
 	return 0;
 }
+
+/*
+ * Old btrfs forgets to init root_item->flags and root_item->byte_limit
+ * for subvolumes. To work around this problem, we steal a bit from
+ * root_item->inode_item->flags, and use it to indicate if those fields
+ * have been properly initialized.
+ */
+void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
+{
+	u64 inode_flags = le64_to_cpu(root_item->inode.flags);
+
+	if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
+		inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
+		root_item->inode.flags = cpu_to_le64(inode_flags);
+		root_item->flags = 0;
+		root_item->byte_limit = 0;
+	}
+}
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index d01cc249a8d36188986fa70b073b054c550cf937..5b158da7e0bb7816710859ee47f7fad4007fb4a2 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -976,6 +976,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	record_root_in_trans(trans, root);
 	btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
 	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
+	btrfs_check_and_init_root_item(new_root_item);
 
 	root_flags = btrfs_root_flags(new_root_item);
 	if (pending->readonly)