JYCache/s3fs/fdcache_stat.cpp

283 lines
7.8 KiB
C++

/*
* s3fs - FUSE-based file system backed by Amazon S3
*
* Copyright(C) 2007 Takeshi Nakatani <ggtakec.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <cerrno>
#include <unistd.h>
#include <sys/file.h>
#include <sys/stat.h>
#include "s3fs_logger.h"
#include "fdcache_stat.h"
#include "fdcache.h"
#include "s3fs_util.h"
#include "s3fs_cred.h"
#include "string_util.h"
//------------------------------------------------
// CacheFileStat class methods
//------------------------------------------------
std::string CacheFileStat::GetCacheFileStatTopDir()
{
std::string top_path;
if(!FdManager::IsCacheDir() || S3fsCred::GetBucket().empty()){
return top_path;
}
// stat top dir( "/<cache_dir>/.<bucket_name>.stat" )
top_path += FdManager::GetCacheDir();
top_path += "/.";
top_path += S3fsCred::GetBucket();
top_path += ".stat";
return top_path;
}
int CacheFileStat::MakeCacheFileStatPath(const char* path, std::string& sfile_path, bool is_create_dir)
{
std::string top_path = CacheFileStat::GetCacheFileStatTopDir();
if(top_path.empty()){
S3FS_PRN_ERR("The path to cache top dir is empty.");
return -EIO;
}
if(is_create_dir){
int result;
if(0 != (result = mkdirp(top_path + mydirname(path), 0777))){
S3FS_PRN_ERR("failed to create dir(%s) by errno(%d).", path, result);
return result;
}
}
if(!path || '\0' == path[0]){
sfile_path = top_path;
}else{
sfile_path = top_path + SAFESTRPTR(path);
}
return 0;
}
bool CacheFileStat::CheckCacheFileStatTopDir()
{
std::string top_path = CacheFileStat::GetCacheFileStatTopDir();
if(top_path.empty()){
S3FS_PRN_INFO("The path to cache top dir is empty, thus not need to check permission.");
return true;
}
return check_exist_dir_permission(top_path.c_str());
}
int CacheFileStat::DeleteCacheFileStat(const char* path)
{
if(!path || '\0' == path[0]){
return -EINVAL;
}
// stat path
std::string sfile_path;
int result;
if(0 != (result = CacheFileStat::MakeCacheFileStatPath(path, sfile_path, false))){
S3FS_PRN_ERR("failed to create cache stat file path(%s)", path);
return result;
}
if(0 != unlink(sfile_path.c_str())){
result = -errno;
if(-ENOENT == result){
S3FS_PRN_DBG("failed to delete file(%s): errno=%d", path, result);
}else{
S3FS_PRN_ERR("failed to delete file(%s): errno=%d", path, result);
}
return result;
}
return 0;
}
// [NOTE]
// If remove stat file directory, it should do before removing
// file cache directory.
//
bool CacheFileStat::DeleteCacheFileStatDirectory()
{
std::string top_path = CacheFileStat::GetCacheFileStatTopDir();
if(top_path.empty()){
S3FS_PRN_INFO("The path to cache top dir is empty, thus not need to remove it.");
return true;
}
return delete_files_in_dir(top_path.c_str(), true);
}
bool CacheFileStat::RenameCacheFileStat(const char* oldpath, const char* newpath)
{
if(!oldpath || '\0' == oldpath[0] || !newpath || '\0' == newpath[0]){
return false;
}
// stat path
std::string old_filestat;
std::string new_filestat;
if(0 != CacheFileStat::MakeCacheFileStatPath(oldpath, old_filestat, false) || 0 != CacheFileStat::MakeCacheFileStatPath(newpath, new_filestat, false)){
return false;
}
// check new stat path
struct stat st;
if(0 == stat(new_filestat.c_str(), &st)){
// new stat path is existed, then unlink it.
if(-1 == unlink(new_filestat.c_str())){
S3FS_PRN_ERR("failed to unlink new cache file stat path(%s) by errno(%d).", new_filestat.c_str(), errno);
return false;
}
}
// check old stat path
if(0 != stat(old_filestat.c_str(), &st)){
// old stat path is not existed, then nothing to do any more.
return true;
}
// link and unlink
if(-1 == link(old_filestat.c_str(), new_filestat.c_str())){
S3FS_PRN_ERR("failed to link old cache file stat path(%s) to new cache file stat path(%s) by errno(%d).", old_filestat.c_str(), new_filestat.c_str(), errno);
return false;
}
if(-1 == unlink(old_filestat.c_str())){
S3FS_PRN_ERR("failed to unlink old cache file stat path(%s) by errno(%d).", old_filestat.c_str(), errno);
return false;
}
return true;
}
//------------------------------------------------
// CacheFileStat methods
//------------------------------------------------
CacheFileStat::CacheFileStat(const char* tpath) : fd(-1)
{
if(tpath && '\0' != tpath[0]){
SetPath(tpath, true);
}
}
CacheFileStat::~CacheFileStat()
{
Release();
}
bool CacheFileStat::SetPath(const char* tpath, bool is_open)
{
if(!tpath || '\0' == tpath[0]){
return false;
}
if(!Release()){
// could not close old stat file.
return false;
}
path = tpath;
if(!is_open){
return true;
}
return Open();
}
bool CacheFileStat::RawOpen(bool readonly)
{
if(path.empty()){
return false;
}
if(-1 != fd){
// already opened
return true;
}
// stat path
std::string sfile_path;
if(0 != CacheFileStat::MakeCacheFileStatPath(path.c_str(), sfile_path, true)){
S3FS_PRN_ERR("failed to create cache stat file path(%s)", path.c_str());
return false;
}
// open
int tmpfd;
if(readonly){
if(-1 == (tmpfd = open(sfile_path.c_str(), O_RDONLY))){
S3FS_PRN_ERR("failed to read only open cache stat file path(%s) - errno(%d)", path.c_str(), errno);
return false;
}
}else{
if(-1 == (tmpfd = open(sfile_path.c_str(), O_CREAT|O_RDWR, 0600))){
S3FS_PRN_ERR("failed to open cache stat file path(%s) - errno(%d)", path.c_str(), errno);
return false;
}
}
scope_guard guard([&]() { close(tmpfd); });
// lock
if(-1 == flock(tmpfd, LOCK_EX)){
S3FS_PRN_ERR("failed to lock cache stat file(%s) - errno(%d)", path.c_str(), errno);
return false;
}
// seek top
if(0 != lseek(tmpfd, 0, SEEK_SET)){
S3FS_PRN_ERR("failed to lseek cache stat file(%s) - errno(%d)", path.c_str(), errno);
flock(tmpfd, LOCK_UN);
return false;
}
S3FS_PRN_DBG("file locked(%s - %s)", path.c_str(), sfile_path.c_str());
guard.dismiss();
fd = tmpfd;
return true;
}
bool CacheFileStat::Open()
{
return RawOpen(false);
}
bool CacheFileStat::ReadOnlyOpen()
{
return RawOpen(true);
}
bool CacheFileStat::Release()
{
if(-1 == fd){
// already release
return true;
}
// unlock
if(-1 == flock(fd, LOCK_UN)){
S3FS_PRN_ERR("failed to unlock cache stat file(%s) - errno(%d)", path.c_str(), errno);
return false;
}
S3FS_PRN_DBG("file unlocked(%s)", path.c_str());
if(-1 == close(fd)){
S3FS_PRN_ERR("failed to close cache stat file(%s) - errno(%d)", path.c_str(), errno);
return false;
}
fd = -1;
return true;
}
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: expandtab sw=4 ts=4 fdm=marker
* vim<600: expandtab sw=4 ts=4
*/