Return block NFS implementation back as an option too

src/nfs_block.h

@@ -0,0 +1,57 @@
+// Copyright (c) Vitaliy Filippov, 2019+
+// License: VNPL-1.1 (see README.md for details)
+//
+// NFS proxy over Vitastor block images - header
+
+#pragma once
+
+struct nfs_dir_t
+{
+    uint64_t id;
+    uint64_t mod_rev;
+    timespec mtime;
+};
+
+struct extend_size_t
+{
+    inode_t inode;
+    uint64_t new_size;
+};
+
+inline bool operator < (const extend_size_t &a, const extend_size_t &b)
+{
+    return a.inode < b.inode || a.inode == b.inode && a.new_size < b.new_size;
+}
+
+struct extend_write_t
+{
+    rpc_op_t *rop;
+    int resize_res, write_res; // 1 = started, 0 = completed OK, -errno = completed with error
+};
+
+struct extend_inode_t
+{
+    uint64_t cur_extend = 0, next_extend = 0;
+};
+
+struct block_fs_state_t
+{
+    // filehandle = "S"+base64(sha256(full name with prefix)) or "roothandle" for mount root)
+    uint64_t next_dir_id = 2;
+    // filehandle => dir with name_prefix
+    std::map<std::string, std::string> dir_by_hash;
+    // dir with name_prefix => dir info
+    std::map<std::string, nfs_dir_t> dir_info;
+    // filehandle => inode ID
+    std::map<std::string, inode_t> inode_by_hash;
+    // inode ID => filehandle
+    std::map<inode_t, std::string> hash_by_inode;
+
+    // inode extend requests in progress
+    std::map<inode_t, extend_inode_t> extends;
+    std::multimap<extend_size_t, extend_write_t> extend_writes;
+
+    void init(nfs_proxy_t *proxy);
+};
+
+nfsstat3 vitastor_nfs_map_err(int err);