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/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "utility.h"
#include <stdint.h>
#include <sys/vfs.h>
#include <unistd.h>
#include <android-base/logging.h>
#include <libfiemap_writer/fiemap_writer.h>
namespace android {
namespace fiemap_writer {
uint64_t DetermineMaximumFileSize(const std::string& file_path) {
// Create the smallest file possible (one block).
auto writer = FiemapWriter::Open(file_path, 1);
if (!writer) {
return 0;
}
uint64_t result = 0;
switch (writer->fs_type()) {
case EXT4_SUPER_MAGIC:
// The minimum is 16GiB, so just report that. If we wanted we could parse the
// superblock and figure out if 64-bit support is enabled.
result = 17179869184ULL;
break;
case F2FS_SUPER_MAGIC:
// Formula is from https://www.kernel.org/doc/Documentation/filesystems/f2fs.txt
// 4KB * (923 + 2 * 1018 + 2 * 1018 * 1018 + 1018 * 1018 * 1018) := 3.94TB.
result = 4329690886144ULL;
break;
case MSDOS_SUPER_MAGIC:
// 4GB-1, which we want aligned to the block size.
result = 4294967295;
result -= (result % writer->block_size());
break;
default:
LOG(ERROR) << "Unknown file system type: " << writer->fs_type();
break;
}
// Close and delete the temporary file.
writer = nullptr;
unlink(file_path.c_str());
return result;
}
} // namespace fiemap_writer
} // namespace android
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