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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2012 Red Hat
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef MDS_CONTEXT_H
#define MDS_CONTEXT_H
#include <vector>
#include <deque>
#include "include/Context.h"
#include "include/elist.h"
#include "include/spinlock.h"
#include "common/ceph_time.h"
class MDSRank;
/**
* Completion which has access to a reference to the global MDS instance.
*
* This class exists so that Context subclasses can provide the MDS pointer
* from a pointer they already had, e.g. MDCache or Locker, rather than
* necessarily having to carry around an extra MDS* pointer.
*/
class MDSContext : public Context
{
public:
template<template<typename> class A>
using vec_alloc = std::vector<MDSContext*, A<MDSContext*>>;
using vec = vec_alloc<std::allocator>;
template<template<typename> class A>
using que_alloc = std::deque<MDSContext*, A<MDSContext*>>;
using que = que_alloc<std::allocator>;
void complete(int r) override;
virtual MDSRank *get_mds() = 0;
};
/* Children of this could have used multiple inheritance with MDSHolder and
* MDSContext but then get_mds() would be ambiguous.
*/
template<class T>
class MDSHolder : public T
{
public:
MDSRank* get_mds() override {
return mds;
}
protected:
MDSHolder() = delete;
MDSHolder(MDSRank* mds) : mds(mds) {
ceph_assert(mds != nullptr);
}
MDSRank* mds;
};
/**
* General purpose, lets you pass in an MDS pointer.
*/
class MDSInternalContext : public MDSHolder<MDSContext>
{
public:
MDSInternalContext() = delete;
protected:
explicit MDSInternalContext(MDSRank *mds_) : MDSHolder(mds_) {}
};
/**
* Wrap a regular Context up as an Internal context. Useful
* if you're trying to work with one of our more generic frameworks.
*/
class MDSInternalContextWrapper : public MDSInternalContext
{
protected:
Context *fin = nullptr;
void finish(int r) override;
public:
MDSInternalContextWrapper(MDSRank *m, Context *c) : MDSInternalContext(m), fin(c) {}
};
class MDSIOContextBase : public MDSContext
{
public:
MDSIOContextBase(bool track=true);
virtual ~MDSIOContextBase();
MDSIOContextBase(const MDSIOContextBase&) = delete;
MDSIOContextBase& operator=(const MDSIOContextBase&) = delete;
void complete(int r) override;
virtual void print(std::ostream& out) const = 0;
static bool check_ios_in_flight(ceph::coarse_mono_time cutoff,
std::string& slow_count,
ceph::coarse_mono_time& oldest);
private:
ceph::coarse_mono_time created_at;
elist<MDSIOContextBase*>::item list_item;
friend struct MDSIOContextList;
};
/**
* Completion for an log operation, takes big MDSRank lock
* before executing finish function. Update log's safe pos
* after finish function return.
*/
class MDSLogContextBase : public MDSIOContextBase
{
protected:
uint64_t write_pos = 0;
public:
MDSLogContextBase() = default;
void complete(int r) final;
void set_write_pos(uint64_t wp) { write_pos = wp; }
virtual void pre_finish(int r) {}
void print(std::ostream& out) const override {
out << "log_event(" << write_pos << ")";
}
};
/**
* Completion for an I/O operation, takes big MDSRank lock
* before executing finish function.
*/
class MDSIOContext : public MDSHolder<MDSIOContextBase>
{
public:
explicit MDSIOContext(MDSRank *mds_) : MDSHolder(mds_) {}
};
/**
* Wrap a regular Context up as an IO Context. Useful
* if you're trying to work with one of our more generic frameworks.
*/
class MDSIOContextWrapper : public MDSHolder<MDSIOContextBase>
{
protected:
Context *fin;
public:
MDSIOContextWrapper(MDSRank *m, Context *c) : MDSHolder(m), fin(c) {}
void finish(int r) override;
void print(std::ostream& out) const override {
out << "io_context_wrapper(" << fin << ")";
}
};
/**
* No-op for callers expecting MDSInternalContext
*/
class C_MDSInternalNoop : public MDSContext
{
public:
void finish(int r) override {}
void complete(int r) override { delete this; }
protected:
MDSRank* get_mds() override final {ceph_abort();}
};
/**
* This class is used where you have an MDSInternalContext but
* you sometimes want to call it back from an I/O completion.
*/
class C_IO_Wrapper : public MDSIOContext
{
protected:
bool async;
MDSContext *wrapped;
void finish(int r) override {
wrapped->complete(r);
wrapped = nullptr;
}
public:
C_IO_Wrapper(MDSRank *mds_, MDSContext *wrapped_) :
MDSIOContext(mds_), async(true), wrapped(wrapped_) {
ceph_assert(wrapped != NULL);
}
~C_IO_Wrapper() override {
if (wrapped != nullptr) {
delete wrapped;
wrapped = nullptr;
}
}
void complete(int r) final;
void print(std::ostream& out) const override {
out << "io_wrapper(" << wrapped << ")";
}
};
using MDSGather = C_GatherBase<MDSContext, C_MDSInternalNoop>;
using MDSGatherBuilder = C_GatherBuilderBase<MDSContext, MDSGather>;
using MDSContextFactory = ContextFactory<MDSContext>;
#endif // MDS_CONTEXT_H
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