meta.cc

nandflash文件系统源代码

/*!
 * $Id: meta.cc 224 2008-12-16 22:48:11Z sriramsrao $ 
 *
 * \file meta.cc
 * \brief Operations on the various metadata types.
 * \author Blake Lewis (Kosmix Corp.)
 *
 * 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.
 */

#include <iostream>
#include <fstream>
#include <sstream>
#include "meta.h"
#include "kfstree.h"
#include "kfstypes.h"
#include "util.h"
#include "LayoutManager.h"

using namespace KFS;

/*
 * Seed the unique id generators for files/chunks to start at 2
 */
UniqueID KFS::fileID(0, ROOTFID);
UniqueID KFS::chunkID(1, ROOTFID);

/*
 * Initialize the chunk version increment to start at 0.  It'll get bumped 
 * when the system starts up.
*/
seq_t KFS::chunkVersionInc = 0;

/*!
 * \brief compare key against test value
 * \param[in] test	the test value
 * \return	negative, zero, or positive, according as the
 * 		this key value is <, =, or > than the test value.
 */
int
Key::compare(const Key &test) const
{
	int kdiff = kind - test.kind;
	int d = 0;

	if (kdiff != 0)
		d = kdiff;
	else if (kdata1 != test.kdata1)
		d = (kdata1 < test.kdata1) ? -1 : 1;
	else if (kdata2 != test.kdata2 &&
		 kdata2 != MATCH_ANY && test.kdata2 != MATCH_ANY)
		d = (kdata2 < test.kdata2) ? -1 : 1;

	return d;
}

const string
MetaDentry::show() const
{
	return "dentry/name/" + name + "/id/" + toString(id()) +
			"/parent/" + toString(dir);
}

bool
MetaDentry::match(Meta *m)
{
	MetaDentry *d = refine<MetaDentry>(m);
	return (d != NULL && d->compareName(name) == 0);
}

string
KFS::showtime(struct timeval t)
{
	std::ostringstream n(std::ostringstream::out);
	n << t.tv_sec << "/" << t.tv_usec;
	return n.str();
}

const string
MetaFattr::show() const
{
	static string fname[] = { "empty", "file", "dir" };

	return "fattr/" + fname[type] + "/id/" + toString(id()) +
		"/chunkcount/" + toString(chunkcount) 
		+ "/numReplicas/" + toString(numReplicas) 
		+ "/mtime/" + showtime(mtime) +
		"/ctime/" + showtime(ctime) + "/crtime/" + showtime(crtime);
}

void
MetaChunkInfo::DeleteChunk()
{
	// if the call to metatree.del() succeeds, the "this" pointer will be
	// deleted.  so, save the chunk id before doing the deletion.
	chunkId_t cid = chunkId;

	// Update the metatree to reflect chunk deletion.  Since we got
	// this MetaChunkInfo by retrieving the allocation information,
	// deletion from the metatree should not fail.
	if (metatree.del(this)) {
		panic("deleteChunk", false);
	}
	gLayoutManager.DeleteChunk(cid);
}

void
MetaChunkInfo::TruncateChunk(off_t s)
{
	gLayoutManager.TruncateChunk(chunkId, s);
}

const string
MetaChunkInfo::show() const
{
	return "chunkinfo/fid/" + toString(id()) + 
		"/chunkid/" + toString(chunkId) + 
		"/offset/" + toString(offset) +
		"/chunkVersion/" + toString(chunkVersion);
}