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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 "hobject.h"
#include "common/Mutex.h"
#include "common/Cond.h"
#include "common/shared_cache.hpp"
#include "include/compat.h"
/**
* FD Cache
*/
class FDCache : public md_config_obs_t {
/**
* FD
*
* Wrapper for an fd. Destructor closes the fd.
*/
class FD {
public:
const int fd;
FD(int _fd) : fd(_fd) {
assert(_fd >= 0);
}
int operator*() const {
return fd;
}
~FD() {
TEMP_FAILURE_RETRY(::close(fd));
}
};
SharedLRU<hobject_t, FD> registry;
CephContext *cct;
public:
FDCache(CephContext *cct) : cct(cct) {
assert(cct);
cct->_conf->add_observer(this);
registry.set_size(cct->_conf->filestore_fd_cache_size);
}
~FDCache() {
cct->_conf->remove_observer(this);
}
typedef std::tr1::shared_ptr<FD> FDRef;
FDRef lookup(const hobject_t &hoid) {
return registry.lookup(hoid);
}
FDRef add(const hobject_t &hoid, int fd) {
return registry.add(hoid, new FD(fd));
}
/// clear cached fd for hoid, subsequent lookups will get an empty FD
void clear(const hobject_t &hoid) {
registry.clear(hoid);
assert(!registry.lookup(hoid));
}
/// md_config_obs_t
const char** get_tracked_conf_keys() const {
static const char* KEYS[] = {
"filestore_fd_cache_size",
NULL
};
return KEYS;
}
void handle_conf_change(const md_config_t *conf,
const std::set<std::string> &changed) {
if (changed.count("filestore_fd_cache_size")) {
registry.set_size(conf->filestore_fd_cache_size);
}
}
};
typedef FDCache::FDRef FDRef;
#endif
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