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XrdCmsManTree.cc
Go to the documentation of this file.
/******************************************************************************/
/* */
/* X r d C m s M a n T r e e . c c */
/* */
/* (c) 2007 by the Board of Trustees of the Leland Stanford, Jr., University */
/* All Rights Reserved */
/* Produced by Andrew Hanushevsky for Stanford University under contract */
/* DE-AC02-76-SFO0515 with the Department of Energy */
/* */
/* This file is part of the XRootD software suite. */
/* */
/* XRootD is free software: you can redistribute it and/or modify it under */
/* the terms of the GNU Lesser General Public License as published by the */
/* Free Software Foundation, either version 3 of the License, or (at your */
/* option) any later version. */
/* */
/* XRootD is distributed in the hope that it will be useful, but WITHOUT */
/* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */
/* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public */
/* License for more details. */
/* */
/* You should have received a copy of the GNU Lesser General Public License */
/* along with XRootD in a file called COPYING.LESSER (LGPL license) and file */
/* COPYING (GPL license). If not, see <http://www.gnu.org/licenses/>. */
/* */
/* The copyright holder's institutional names and contributor's names may not */
/* be used to endorse or promote products derived from this software without */
/* specific prior written permission of the institution or contributor. */
/******************************************************************************/
#include <cstdio>
#include "XProtocol/YProtocol.hh"
#include "XrdCms/XrdCmsManTree.hh"
#include "XrdCms/XrdCmsNode.hh"
#include "XrdCms/XrdCmsTrace.hh"
using namespace XrdCms;
/******************************************************************************/
/* C o n s t r u c t o r */
/******************************************************************************/
XrdCmsManTree::XrdCmsManTree(int maxC) : maxTMI(0), numConn(0), maxConn(maxC),
atRoot(0), conLevel(0), conNID(-1),
numWaiting(0), myStatus(Active)
{
snprintf(buff, sizeof(buff), "%d", maxC);
}
/******************************************************************************/
/* A b o r t */
/******************************************************************************/
void XrdCmsManTree::Abort()
{
XrdSysMutexHelper Monitor(myMutex);
// An abort may be issued to make sure no one is waiting to participate in
// tree construction. It's usually issued when the manager object has been
// permanently redirected.
//
if (myStatus != Aborted && numWaiting)
{for (int i = 0; i < maxTMI; i++)
if (tmInfo[i].Status == Waiting) {tmInfo[i].Level = 0; Redrive(i);}
}
// Indicate we have aborted
//
myStatus = Aborted;
}
/******************************************************************************/
/* C o n n e c t */
/******************************************************************************/
int XrdCmsManTree::Connect(int nID, XrdCmsNode *nP)
{
static CmsDiscRequest discRequest = {{0, kYR_disc, 0, 0}};
XrdSysMutexHelper Monitor(myMutex);
char mybuff[16];
int i;
// Rule 0: If we aborted tell the client to just stop doing this
//
if (myStatus == Aborted) return 0;
// Rule 1: If we are already connected, thell the caller to disband the
// connection as we must have a connection to an interior node.
//
if (myStatus == Connected) return 0;
numConn++;
tmInfo[nID].nodeP = nP;
// Rule 2: If we connected to a root node then consider ourselves connected
// only if all connections are to the root.
//
if (tmInfo[nID].Level == 0)
{if (numConn == maxConn)
{myStatus = Connected; conLevel = 0; atRoot = 1;
Say.Emsg("ManTree", "Now connected to", buff, "root node(s)");
}
tmInfo[nID].Status = Connected;
return 1;
}
// Rule 3: We connected to an interior node. Disband all other existing
// connections (these should only be to root nodes) and consider
// ourselves connected.
//
for (i = 0; i < maxTMI; i++)
if (i != nID && tmInfo[i].Status == Connected)
{tmInfo[i].nodeP->Send((char *)&discRequest, sizeof(discRequest));
tmInfo[i].Status = Pending;
}
myStatus = Connected;
conLevel = tmInfo[nID].Level;
conNID = nID;
atRoot = 0;
// Document our connection configuration
//
snprintf(mybuff, sizeof(mybuff), "%d", conLevel);
Say.Emsg("ManTree", "Now connected to supervisor at level", mybuff);
return 1;
}
/******************************************************************************/
/* D i s c */
/******************************************************************************/
void XrdCmsManTree::Disc(int nID)
{
// A connected caller has lost it's connection.
//
myMutex.Lock();
if (tmInfo[nID].Status == Connected || tmInfo[nID].Status == Pending)
numConn--;
tmInfo[nID].Status = Active;
if (atRoot || (conLevel && conNID == nID)) myStatus = Active;
tmInfo[nID].nodeP = 0;
myMutex.UnLock();
}
/******************************************************************************/
/* R e g i s t e r */
/******************************************************************************/
int XrdCmsManTree::Register()
{
int nID;
// Add this server to the tree table. Register is called only once and there
// can be no more than MTMax connections to a manager. Hence, we dispense with
// error checking (how optimistic :-)
//
myMutex.Lock();
tmInfo[maxTMI].Status= Active;
nID = maxTMI; maxTMI++;
myMutex.UnLock();
return nID;
}
/******************************************************************************/
/* T r y i n g */
/******************************************************************************/
// This method arranges server connections to a manager to form a minimal B-Tree
// free of phantom arcs. The rule is simple, either all connections are to the
// root of tree or there is only one connection to an interior node. Because
// node discovery is non-determinstic, we must make sure that all root nodes
// are tried so as to discover the full set of supervisor nodes we can contact.
// This method returns True if the caller may continue at the indicated level
// and False if the caller should restart at the root node.
//
int XrdCmsManTree::Trying(int nID, int lvl)
{
int i;
// Set the current status of the connection
//
myMutex.Lock();
tmInfo[nID].Level = lvl;
// Rule 0: If we aborted tell the client to just stop doing this
//
if (myStatus == Aborted) return -1;
// Rule 1: If we are already connected at level >0 then the caller must wait
//
if (myStatus == Connected && conLevel > 0)
{Pause(nID);
return (lvl == tmInfo[nID].Level);
}
// Rule 2: If the caller is trying level 0 then any waiting threads must be
// allowed to continue but forced to level 0. This allows us to discover
// all the supervisors connected to the root.
//
if (!lvl)
{if (numWaiting)
{for (i = 0; i < maxTMI; i++)
if (i != nID && tmInfo[i].Status == Waiting)
{tmInfo[i].Level = 0; Redrive(i);}
}
myMutex.UnLock();
return 1;
}
// Rule 3: If the caller is trying at a non-zero level (interior node) and
// someone else is trying at a non-zero level, then the caller must
// wait.
//
for (i = 0; i < maxTMI; i++)
if (i != nID && tmInfo[i].Status == Active && tmInfo[i].Level) break;
if (i < maxTMI) Pause(nID);
else myMutex.UnLock();
// The caller may continue. Indicate whether the caller must restart at the
// root node. If the caller may continue trying to connect to an interior
// node then it's the only thread trying to do so.
//
return (lvl == tmInfo[nID].Level);
}
XrdCmsManTree.hh
XrdCmsNode.hh
XrdCmsTrace.hh
YProtocol.hh
XrdCmsManTree::Connect
int Connect(int nID, XrdCmsNode *nP)
Definition XrdCmsManTree.cc:78
XrdCmsManTree::Abort
void Abort()
Definition XrdCmsManTree.cc:56
XrdCmsManTree::Register
int Register()
Definition XrdCmsManTree.cc:151
XrdCmsManTree::Active
@ Active
Definition XrdCmsManTree.hh:52
XrdCmsManTree::Waiting
@ Waiting
Definition XrdCmsManTree.hh:52
XrdCmsManTree::Pending
@ Pending
Definition XrdCmsManTree.hh:52
XrdCmsManTree::Aborted
@ Aborted
Definition XrdCmsManTree.hh:52
XrdCmsManTree::Connected
@ Connected
Definition XrdCmsManTree.hh:52
XrdCmsManTree::Disc
void Disc(int nID)
Definition XrdCmsManTree.cc:133
XrdCmsManTree::XrdCmsManTree
XrdCmsManTree(int maxC)
Definition XrdCmsManTree.cc:45
XrdCmsManTree::Trying
int Trying(int nID, int Lvl)
Definition XrdCmsManTree.cc:178
XrdCmsNode
Definition XrdCmsNode.hh:58
XrdSysMutexHelper
Definition XrdSysPthread.hh:263
XrdCms
Definition YProtocol.hh:78
XrdCms::Say
XrdSysError Say
Definition XrdCmsManager.cc:62
XrdCms::kYR_disc
@ kYR_disc
Definition YProtocol.hh:103
XrdCms::CmsDiscRequest
Definition YProtocol.hh:212