Unable to get disks' serial number with IOCounters on linux

[jbliao]

Describe the bug
IOCountersStat.SerialNumber always have no value on linux

I use telegraf to monitor disk which use this go module to get disk info, and the serial of disk always be null.

To Reproduce

package main

import (
    "github.com/shirou/gopsutil/v3/disk"
    "fmt"
)

func main() {
    info, err := disk.IOCounters("/dev/sda")
    if (err != nil) {
        fmt.Print(err)
    }
    fmt.Println(info)

    serialNumber, err := disk.SerialNumber("/dev/sda")
    if (err != nil) {
        fmt.Print(err)
    }
    fmt.Println(serialNumber)

    serialNumber, err = disk.SerialNumber("sda")
    if (err != nil) {
        fmt.Print(err)
    }
    fmt.Println(serialNumber)

}                                 

result:

map[sda:{"readCount":398790,"mergedReadCount":1,"writeCount":613726,"mergedWriteCount":360,"readBytes":20676746240,"writeBytes":55764192768,"readTime":3302034,"writeTime":2927377,"iopsInProgress":0,"ioTime":6360176,"weightedIO":8757288,"name":"sda","serialNumber":"","label":""}]
INTEL_SSDSC2BW240A4_CVDA4152****<CENSORED>***
no such file or directory

Expected behavior
disk.IOCounters should contain serial number of disks.

Environment (please complete the following information):
Linux: [paste contents of /etc/os-release and the result of uname -a]

• cat /etc/os_release

PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"
NAME="Debian GNU/Linux"
VERSION_ID="11"
VERSION="11 (bullseye)"
VERSION_CODENAME=bullseye
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"

• uname -a

Linux truenas.local 5.10.42+truenas #1 SMP Mon Aug 30 21:54:59 UTC 2021 x86_64 GNU/Linux

Additional context
Actually this line will fail every time when it was called from IOCounters

gopsutil/v3/disk/disk_linux.go

Line 444 in 8d7a3ab

err := unix.Stat(name, &stat)

The name variable should prepend /dev/

[shirou]

According to your report, disk.SerialNumber("/dev/sda") seems succeeded (and I confirmed it works on my local). Why do you want to specify "sda"?

[jbliao]

Let me clarify the problem:
I want to use disk.IOCounters() to get disk metrics and disks' serial number. So I called the disk.IOCounters() function with parameter names be something like ["/dev/sda", "/dev/sdb"...].
And in the disk.IOCountersWithContext(), the d.SerialNumber is assigned by disk.SerialNumberWithContext() with name as parameter and ignoring errors.
But the name variable gets from /proc/diskstats in sd* form. So it always call disk.SerialNumberWithContext(ctx, "sd*") and return nil. Resulting the d.SerialNumber always be nil.

My /proc/diskstats content:

   8      32 sdc 6508176 2140 343843184 128561381 47193964 128738 10152207944 88815557 0 129623272 259779266 0 0 0 0 617986 42402327
   8      33 sdc1 4141977 1731 198099728 59194364 34480392 56622 1384411560 16132962 0 75348828 75327327 0 0 0 0 0 0
   8      34 sdc2 803820 409 145191421 25014458 12713572 72116 8767796384 72682595 0 36338908 97697053 0 0 0 0 0 0
   8      16 sdb 9370854 6991 875144226 10833192 26557788 865337 2008727912 14142041 0 47574900 27519676 0 0 0 0 1268299 2544441