request.h

nandflash文件系统源代码

/*!
 * $Id: request.h 237 2009-01-09 07:45:20Z sriramsrao $ 
 *
 * \file request.h
 * \brief protocol requests to KFS metadata server
 * \author Blake Lewis (Kosmix Corp.)
 *
 * The model is that various receiver threads handle network
 * connections and extract RPC parameters, then queue a request
 * of the appropriate type for the metadata server to process.
 * When the operation is finished, the server calls back to the
 * receiver with status and any results.
 *
 * Copyright 2008 Quantcast Corp.
 * Copyright 2006-2008 Kosmix Corp.
 *
 * This file is part of Kosmos File System (KFS).
 *
 * Licensed under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */
#if !defined(KFS_REQUEST_H)
#define KFS_REQUEST_H

#include "common/kfsdecls.h"
#include "kfstypes.h"
#include "meta.h"
#include "thread.h"
#include "util.h"
#include <deque>
#include <fstream>
#include <sstream>
#include <vector>

#include "libkfsIO/KfsCallbackObj.h"

using std::ofstream;
using std::vector;
using std::ostringstream;

namespace KFS {

/*!
 * \brief Metadata server operations
 */
enum MetaOp {
	// Client -> Metadata server ops
	META_LOOKUP,
	META_LOOKUP_PATH,
	META_CREATE,
	META_MKDIR,
	META_REMOVE,
	META_RMDIR,
	META_READDIR,
	META_READDIRPLUS,
	META_GETALLOC,
	META_GETLAYOUT,
	META_GETDIRSUMMARY,
	META_ALLOCATE,
	META_TRUNCATE,
	META_RENAME,
	META_LOG_ROLLOVER,
	META_CHANGE_FILE_REPLICATION, //! < Client is asking for a change in file's replication factor
	//!< Admin is notifying us to retire a chunkserver
	META_RETIRE_CHUNKSERVER,
	//!< Admin is notifying us to toggle rebalancing
	META_TOGGLE_REBALANCING,
	//!< Admin is notifying us to execute a rebalance plan
	META_EXECUTE_REBALANCEPLAN,
	META_TOGGLE_WORM, //!< Toggle metaserver's WORM mode
	//!< Metadata server <-> Chunk server ops
	META_HELLO,  //!< Hello RPC sent by chunkserver on startup
	META_BYE,  //!< Internally generated op whenever a chunkserver goes down
	META_CHUNK_HEARTBEAT, //!< Periodic heartbeat from meta->chunk
	META_CHUNK_ALLOCATE, //!< Allocate chunk RPC from meta->chunk
	META_CHUNK_DELETE,  //!< Delete chunk RPC from meta->chunk
	META_CHUNK_TRUNCATE, //!< Truncate chunk RPC from meta->chunk
	META_CHUNK_STALENOTIFY, //!< Stale chunk notification RPC from meta->chunk
	META_CHUNK_VERSCHANGE, //!< Notify chunkserver of version # change from meta->chunk
	META_CHUNK_REPLICATE, //!< Ask chunkserver to replicate a chunk
	META_CHUNK_SIZE, //!< Ask chunkserver for the size of a chunk
	META_CHUNK_REPLICATION_CHECK, //!< Internally generated
	META_CHUNK_CORRUPT, //!< Chunkserver is notifying us that a chunk is corrupt
	//!< All the blocks on the retiring server have been evacuated and the
	//!< server can safely go down.  We are asking the server to take a graceful bow
	META_CHUNK_RETIRE,
	//!< Lease related messages
	META_LEASE_ACQUIRE,
	META_LEASE_RENEW,
	META_LEASE_RELINQUISH,
	//!< Internally generated to cleanup leases
	META_LEASE_CLEANUP,
	//!< Internally generated to update the increment for chunk version #'s
	META_CHANGE_CHUNKVERSIONINC,

	//!< Metadata server monitoring
	META_PING, //!< Print out chunkserves and their configs
	META_STATS, //!< Print out whatever statistics/counters we have
	META_DUMP_CHUNKTOSERVERMAP, //! < Dump out the chunk -> location map
	META_OPEN_FILES, //!< Print out open files---for which there is a valid read/write lease
	META_UPSERVERS //!< Print out live chunk servers

};

/*!
 * \brief Meta request base class
 */
struct MetaRequest {
	const MetaOp op; //!< type of request
	int status;	//!< returned status
	seq_t opSeqno;	//!< command sequence # sent by the client
	seq_t seqno;	//!< sequence no. in log
	const bool mutation; //!< mutates metatree
	bool suspended;  //!< is this request suspended somewhere
	KfsCallbackObj *clnt; //!< a handle to the client that generated this request.
	MetaRequest(MetaOp o, seq_t ops, bool mu):
		op(o), status(0), opSeqno(ops), seqno(0), mutation(mu),
		suspended(false), clnt(NULL) { }
	virtual ~MetaRequest() { }

	//!< when an op finishes execution, we send a response back to
	//!< the client.  This function should generate the appropriate
	//!< response to be sent back as per the KFS protocol.
	virtual void response(ostringstream &os)
	{
		(void) os; // XXX avoid spurious compiler warnings
	};
	virtual int log(ofstream &file) const = 0; //!< write request to log
	virtual string Show() { return ""; }
};

/*!
 * \brief look up a file name
 */
struct MetaLookup: public MetaRequest {
	fid_t dir;	//!< parent directory fid
	string name;	//!< name to look up
	MetaFattr result; //!< result of lookup
	MetaLookup(seq_t s, fid_t d, string n):
		MetaRequest(META_LOOKUP, s, false), dir(d), name(n) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "lookup: name = " << name;
		os << " (parent fid = " << dir << ")";
		return os.str();
	}
};

/*!
 * \brief look up a complete path
 */
struct MetaLookupPath: public MetaRequest {
	fid_t root;	//!< fid of starting directory
	string path;	//!< path to look up
	MetaFattr result; //!< result of lookup;
	MetaLookupPath(seq_t s, fid_t r, string p):
		MetaRequest(META_LOOKUP_PATH, s, false), root(r), path(p) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "lookup_path: path = " << path;
		os << " (root fid = " << root << ")";
		return os.str();
	}
};

/*!
 * \brief create a file
 */
struct MetaCreate: public MetaRequest {
	fid_t dir;	//!< parent directory fid
	string name;	//!< name to create
	fid_t fid;	//!< file ID of new file
	int16_t numReplicas; //!< desired degree of replication
	bool exclusive;  //!< model the O_EXCL flag
	MetaCreate(seq_t s, fid_t d, string n, int16_t r, bool e):
		MetaRequest(META_CREATE, s, true), dir(d),
		name(n), numReplicas(r), exclusive(e) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "create: name = " << name;
		os << " (parent fid = " << dir << ")";
		os << " desired replication = " << numReplicas;
		return os.str();
	}
};

/*!
 * \brief create a directory
 */
struct MetaMkdir: public MetaRequest {
	fid_t dir;	//!< parent directory fid
	string name;	//!< name to create
	fid_t fid;	//!< file ID of new directory
	MetaMkdir(seq_t s, fid_t d, string n):
		MetaRequest(META_MKDIR, s, true), dir(d), name(n) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "mkdir: name = " << name;
		os << " (parent fid = " << dir << ")";
		return os.str();
	}
};

/*!
 * \brief remove a file
 */
struct MetaRemove: public MetaRequest {
	fid_t dir;	//!< parent directory fid
	string name;	//!< name to remove
	MetaRemove(seq_t s, fid_t d, string n):
		MetaRequest(META_REMOVE, s, true), dir(d), name(n) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "remove: name = " << name;
		os << " (parent fid = " << dir << ")";
		return os.str();
	}
};

/*!
 * \brief remove a directory
 */
struct MetaRmdir: public MetaRequest {
	fid_t dir;	//!< parent directory fid
	string name;	//!< name to remove
	MetaRmdir(seq_t s, fid_t d, string n):
		MetaRequest(META_RMDIR, s, true), dir(d), name(n) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "rmdir: name = " << name;
		os << " (parent fid = " << dir << ")";
		return os.str();
	}
};

/*!
 * \brief read directory contents
 */
struct MetaReaddir: public MetaRequest {
	fid_t dir;	//!< directory to read
	vector <MetaDentry> v; //!< vector of results
	MetaReaddir(seq_t s, fid_t d):
		MetaRequest(META_READDIR, s, false), dir(d) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "readdir: dir fid = " << dir;
		return os.str();
	}
};

/*!
 * \brief read directory contents and get file attributes
 */
struct MetaReaddirPlus: public MetaRequest {
	fid_t dir;	//!< directory to read
	ostringstream v; //!< results built out into a string
	int numEntries; //!< # of entries in the directory
	MetaReaddirPlus(seq_t s, fid_t d):
		MetaRequest(META_READDIRPLUS, s, false), dir(d) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "readdir: dir fid = " << dir;
		return os.str();
	}
};

/*!
 * \brief get allocation info. a chunk for a file
 */
struct MetaGetalloc: public MetaRequest {
	fid_t fid;	//!< file for alloc info is needed
	chunkOff_t offset; //!< offset of chunk within file
	chunkId_t chunkId; //!< Id of the chunk corresponding to offset
	seq_t chunkVersion; //!< version # assigned to this chunk
	vector<ServerLocation> locations; //!< where the copies of the chunks are
	MetaGetalloc(seq_t s, fid_t f, chunkOff_t o):
		MetaRequest(META_GETALLOC, s, false), fid(f), offset(o) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "getalloc: fid = " << fid;
		os << " offset = " << offset;
		return os.str();
	}
};

/*!
 * \brief layout information for a chunk
 */
struct ChunkLayoutInfo {
	chunkOff_t offset; //!< offset of chunk within file
	chunkId_t chunkId; //!< Id of the chunk corresponding to offset
	seq_t chunkVersion; //!< version # assigned to this chunk
	vector<ServerLocation> locations; //!< where the copies of the chunks are
	string toString()
	{
		ostringstream os;

		os << offset << " " << chunkId << " " ;
		os << chunkVersion << " " << locations.size() << " ";
		for (vector<ServerLocation>::size_type i = 0;
			i < locations.size(); ++i) {
			os << locations[i].hostname << " " << locations[i].port << " ";
		}
		return os.str();
	}
};

/*!
 * \brief get allocation info. for all chunks of a file
 */
struct MetaGetlayout: public MetaRequest {
	fid_t fid;	//!< file for layout info is needed
	vector <ChunkLayoutInfo> v; //!< vector of results
	MetaGetlayout(seq_t s, fid_t f):
		MetaRequest(META_GETLAYOUT, s, false), fid(f) { }
	int log(ofstream &file) const;
	void response(ostringstream &os);
	string Show()
	{
		ostringstream os;

		os << "getlayout: fid = " << fid;
		return os.str();
	}