ceremonyclient/pebble/vfs/disk_usage_linux.go
Cassandra Heart 2e2a1e4789
v1.2.0 (#31)
2024-01-03 01:31:42 -06:00

45 lines
1.5 KiB
Go

// Copyright 2020 The LevelDB-Go and Pebble Authors. All rights reserved. Use
// of this source code is governed by a BSD-style license that can be found in
// the LICENSE file.
//go:build linux
// +build linux
package vfs
import "golang.org/x/sys/unix"
func (defaultFS) GetDiskUsage(path string) (DiskUsage, error) {
stat := unix.Statfs_t{}
if err := unix.Statfs(path, &stat); err != nil {
return DiskUsage{}, err
}
// We use stat.Frsize here rather than stat.Bsize because on
// Linux Bavail and Bfree are in Frsize units.
//
// On most filesystems Frsize and Bsize will be set to the
// same value, but on some filesystems bsize returns the
// "optimal transfer block size"[1] which may be different
// (typically larger) than the actual block size.
//
// This confusion is cleared up in the statvfs[2] libc function,
// but the statfs system call used above varies across
// platforms.
//
// Frsize is used by GNU coreutils and other libraries, so
// this also helps ensure that we get the same results as one
// would get if they ran `df` on the given path.
//
// [1] https://man7.org/linux/man-pages/man2/statfs.2.html
// [2] https://man7.org/linux/man-pages/man3/statvfs.3.html
freeBytes := uint64(stat.Frsize) * uint64(stat.Bfree)
availBytes := uint64(stat.Frsize) * uint64(stat.Bavail)
totalBytes := uint64(stat.Frsize) * uint64(stat.Blocks)
return DiskUsage{
AvailBytes: availBytes,
TotalBytes: totalBytes,
UsedBytes: totalBytes - freeBytes,
}, nil
}