github.com/zuoyebang/bitalostable@v1.0.1-0.20240229032404-e3b99a834294/vfs/disk_usage_linux.go (about)

     1  // Copyright 2020 The LevelDB-Go and Pebble Authors. All rights reserved. Use
     2  // of this source code is governed by a BSD-style license that can be found in
     3  // the LICENSE file.
     4  
     5  //go:build linux
     6  // +build linux
     7  
     8  package vfs
     9  
    10  import "golang.org/x/sys/unix"
    11  
    12  func (defaultFS) GetDiskUsage(path string) (DiskUsage, error) {
    13  	stat := unix.Statfs_t{}
    14  	if err := unix.Statfs(path, &stat); err != nil {
    15  		return DiskUsage{}, err
    16  	}
    17  
    18  	// We use stat.Frsize here rather than stat.Bsize because on
    19  	// Linux Bavail and Bfree are in Frsize units.
    20  	//
    21  	// On most filesystems Frsize and Bsize will be set to the
    22  	// same value, but on some filesystems bsize returns the
    23  	// "optimal transfer block size"[1] which may be different
    24  	// (typically larger) than the actual block size.
    25  	//
    26  	// This confusion is cleared up in the statvfs[2] libc function,
    27  	// but the statfs system call used above varies across
    28  	// platforms.
    29  	//
    30  	// Frsize is used by GNU coreutils and other libraries, so
    31  	// this also helps ensure that we get the same results as one
    32  	// would get if they ran `df` on the given path.
    33  	//
    34  	// [1] https://man7.org/linux/man-pages/man2/statfs.2.html
    35  	// [2] https://man7.org/linux/man-pages/man3/statvfs.3.html
    36  	freeBytes := uint64(stat.Frsize) * uint64(stat.Bfree)
    37  	availBytes := uint64(stat.Frsize) * uint64(stat.Bavail)
    38  	totalBytes := uint64(stat.Bsize) * uint64(stat.Blocks)
    39  	return DiskUsage{
    40  		AvailBytes: availBytes,
    41  		TotalBytes: totalBytes,
    42  		UsedBytes:  totalBytes - freeBytes,
    43  	}, nil
    44  }