nfs4: Add link() hook

src/add-ons/kernel/file_systems/nfs4/Inode.cpp

@@ -210,6 +210,56 @@ Inode::LookUp(const char* name, ino_t* id)
 }
 
 
+status_t
+Inode::Link(Inode* dir, const char* name)
+{
+	do {
+		RPC::Server* serv = fFilesystem->Server();
+		Request request(serv);
+		RequestBuilder& req = request.Builder();
+
+		req.PutFH(fHandle);
+		req.SaveFH();
+		req.PutFH(dir->fHandle);
+		req.Link(name);
+
+		status_t result = request.Send();
+		if (result != B_OK)
+			return result;
+
+		ReplyInterpreter& reply = request.Reply();
+
+		// filehandle has expired
+		if (reply.NFS4Error() == NFS4ERR_FHEXPIRED) {
+			_LookUpFilehandle();
+			dir->_LookUpFilehandle();
+			continue;
+		}
+
+		// filesystem has been moved
+		if (reply.NFS4Error() == NFS4ERR_MOVED) {
+			fFilesystem->Migrate(fHandle, serv);
+			dir->fFilesystem->Migrate(dir->fHandle, serv);
+			continue;
+		}
+
+		result = reply.PutFH();
+		if (result != B_OK)
+			return result;
+
+		result = reply.SaveFH();
+		if (result != B_OK)
+			return result;
+
+		result = reply.PutFH();
+		if (result != B_OK)
+			return result;
+
+		return reply.Link();
+	} while (true);
+}
+
+
 // May cause problem similar to Rename (described below). When node's is has
 // more than one hard link and we delete the name it stores for filehandle
 // restoration node will inocorectly become unavailable.

src/add-ons/kernel/file_systems/nfs4/Inode.h

@@ -32,6 +32,7 @@ public:
 
 					status_t	LookUp(const char* name, ino_t* id);
 					status_t	ReadLink(void* buffer, size_t* length);
+					status_t	Link(Inode* dir, const char* name);
 					status_t	Remove(const char* name, FileType type);
 	static			status_t	Rename(Inode* from, Inode* to,
 									const char* fromName, const char* toName);

src/add-ons/kernel/file_systems/nfs4/NFS4Defs.h

@@ -25,6 +25,7 @@ enum Opcode {
 	OpClose					= 4,
 	OpGetAttr				= 9,
 	OpGetFH					= 10,
+	OpLink					= 11,
 	OpLookUp				= 15,
 	OpLookUpUp				= 16,
 	OpOpen					= 18,

src/add-ons/kernel/file_systems/nfs4/ReplyInterpreter.cpp

@@ -173,6 +173,21 @@ ReplyInterpreter::GetFH(Filehandle* fh)
 }
 
 
+status_t
+ReplyInterpreter::Link()
+{
+	status_t res = _OperationError(OpLink);
+	if (res != B_OK)
+		return res;
+
+	fReply->Stream().GetBoolean();
+	fReply->Stream().GetUHyper();
+	fReply->Stream().GetUHyper();
+
+	return fReply->Stream().IsEOF() ? B_BAD_VALUE : B_OK;
+}
+
+
 status_t
 ReplyInterpreter::Open(uint32* id, uint32* seq, bool* confirm)
 {

src/add-ons/kernel/file_systems/nfs4/ReplyInterpreter.h

@@ -68,6 +68,7 @@ public:
 			status_t	Close();
 			status_t	GetAttr(AttrValue** attrs, uint32* count);
 			status_t	GetFH(Filehandle* fh);
+			status_t	Link();
 	inline	status_t	LookUp();
 	inline	status_t	LookUpUp();
 			status_t	Open(uint32* id, uint32* seq, bool* confirm);

src/add-ons/kernel/file_systems/nfs4/RequestBuilder.cpp

@@ -118,6 +118,24 @@ RequestBuilder::GetFH()
 }
 
 
+status_t
+RequestBuilder::Link(const char* name)
+{
+	if (fProcedure != ProcCompound)
+		return B_BAD_VALUE;
+	if (fRequest == NULL)
+		return B_NO_MEMORY;
+	if (name == NULL)
+		return B_BAD_VALUE;
+
+	fRequest->Stream().AddUInt(OpLink);
+	fRequest->Stream().AddString(name);
+	fOpCount++;
+
+	return B_OK;
+}
+
+
 status_t
 RequestBuilder::LookUp(const char* name)
 {

src/add-ons/kernel/file_systems/nfs4/RequestBuilder.h

@@ -30,6 +30,7 @@ public:
 										uint32 stateSeq);
 			status_t				GetAttr(Attribute* attrs, uint32 count);
 			status_t				GetFH();
+			status_t				Link(const char* name);
 			status_t				LookUp(const char* name);
 			status_t				LookUpUp();
 			status_t				Open(OpenClaim claim, uint32 seq,

src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp

@@ -212,6 +212,15 @@ nfs4_read_symlink(fs_volume* volume, fs_vnode* link, char* buffer,
 }
 
 
+static status_t
+nfs4_link(fs_volume* volume, fs_vnode* dir, const char* name, fs_vnode* vnode)
+{
+	Inode* inode = reinterpret_cast<Inode*>(vnode->private_node);
+	Inode* dirInode = reinterpret_cast<Inode*>(dir->private_node);
+	return inode->Link(dirInode, name);
+}
+
+
 static status_t
 nfs4_unlink(fs_volume* volume, fs_vnode* dir, const char* name)
 {
@@ -449,7 +458,7 @@ fs_vnode_ops gNFSv4VnodeOps = {
 	nfs4_read_symlink,
 	NULL,	// create_symlink()
 
-	NULL,	// link()
+	nfs4_link,
 	nfs4_unlink,
 	nfs4_rename,