CODEWITHSUNDEEP
go
Amin
Amin

Reputation: 643

How to get number of free inodes? (`df -i` equivalent)

Is there a way to check the number of available/used/total inodes on a filesystem in Go?

I want something just like what df -i returns, and don't want to call df if possible.

Example of df:

# On macOs 10.15 (-i not needed here)
df /
Filesystem   512-blocks     Used Available Capacity iused      ifree %iused  Mounted on
/dev/disk1s2  236568496 22038704  44026328    34%  488339 1182354141    0%   /

# On Ubuntu 18.04
df -i /
Filesystem      Inodes  IUsed   IFree IUse% Mounted on
/dev/vda1      2621440 219719 2401721    9% /

Upvotes: 2

Views: 1718

Answers (2)

Mark Plotnick
Mark Plotnick

Reputation: 10271

You can use syscall.Statfs. Its arguments are a pathname and a pointer to a Statfs_t struct. It fills in the struct with statistics for the filesystem that contains the file or directory specified by the pathname. Typically you'd use . or / or the pathname of a mount point.

Here's a Go program that takes a pathname as its argument and displays inode information.

package main

import (
    "fmt"
    "os"
    "syscall"
)

func main() {
    var statfs syscall.Statfs_t
    path := os.Args[1]
    if err := syscall.Statfs(path, &statfs); err != nil {
        fmt.Fprintf(os.Stderr, "Cannot stat %s: %v\n", path, err)
        os.Exit(1)
    }
    fmt.Printf("Inodes: total %d, free %d\n", statfs.Files, statfs.Ffree)
}

Upvotes: 2

Shang Jian Ding
Shang Jian Ding

Reputation: 2146

On the systems that you mentioned, macOs and Ubuntu, you can use

func Fstatfs(fd int, buf *Statfs_t) (err error) .

The input argument *unix.Statfs_t would then be updated assuming the unix.Fstatfs call doesn't error.

unix.Statfs_t.Files and unix.Statfs_t.Ffree are total number of inodes and number of free inodes respectively for the filesystem that corresponds to the fd, the first arugment of the unix.Fstatfs call.

See also: manual of statfs system call

Upvotes: 2

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