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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) 2013 Inktank Storage, Inc.
*
* 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 CEPH_FDCACHE_H
#define CEPH_FDCACHE_H
#include <memory>
#include <errno.h>
#include <cstdio>
#include "common/config_obs.h"
#include "common/hobject.h"
#include "common/Mutex.h"
#include "common/Cond.h"
#include "common/shared_cache.hpp"
#include "include/compat.h"
#include "include/intarith.h"
/**
* FD Cache
*/
class FDCache : public md_config_obs_t {
public:
/**
* FD
*
* Wrapper for an fd. Destructor closes the fd.
*/
class FD {
public:
const int fd;
explicit FD(int _fd) : fd(_fd) {
ceph_assert(_fd >= 0);
}
int operator*() const {
return fd;
}
~FD() {
VOID_TEMP_FAILURE_RETRY(::close(fd));
}
};
private:
CephContext *cct;
const int registry_shards;
SharedLRU<ghobject_t, FD> *registry;
public:
explicit FDCache(CephContext *cct) : cct(cct),
registry_shards(std::max<int64_t>(cct->_conf->filestore_fd_cache_shards, 1)) {
ceph_assert(cct);
cct->_conf.add_observer(this);
registry = new SharedLRU<ghobject_t, FD>[registry_shards];
for (int i = 0; i < registry_shards; ++i) {
registry[i].set_cct(cct);
registry[i].set_size(
std::max<int64_t>((cct->_conf->filestore_fd_cache_size / registry_shards), 1));
}
}
~FDCache() override {
cct->_conf.remove_observer(this);
delete[] registry;
}
typedef std::shared_ptr<FD> FDRef;
FDRef lookup(const ghobject_t &hoid) {
int registry_id = hoid.hobj.get_hash() % registry_shards;
return registry[registry_id].lookup(hoid);
}
FDRef add(const ghobject_t &hoid, int fd, bool *existed) {
int registry_id = hoid.hobj.get_hash() % registry_shards;
return registry[registry_id].add(hoid, new FD(fd), existed);
}
/// clear cached fd for hoid, subsequent lookups will get an empty FD
void clear(const ghobject_t &hoid) {
int registry_id = hoid.hobj.get_hash() % registry_shards;
registry[registry_id].purge(hoid);
}
/// md_config_obs_t
const char** get_tracked_conf_keys() const override {
static const char* KEYS[] = {
"filestore_fd_cache_size",
NULL
};
return KEYS;
}
void handle_conf_change(const ConfigProxy& conf,
const std::set<std::string> &changed) override {
if (changed.count("filestore_fd_cache_size")) {
for (int i = 0; i < registry_shards; ++i)
registry[i].set_size(
std::max<int64_t>((conf->filestore_fd_cache_size / registry_shards), 1));
}
}
};
typedef FDCache::FDRef FDRef;
#endif
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