Can't mount ext4 partition under windows using WSL2. Fails to mount with error code: -1

[IAmV0id]

Environment

Windows build number: Microsoft Windows [Version 10.0.20270.1]
Your Distribution version: Ubuntu 20.04
Problem is on WSL2

Steps to reproduce

Open powershell with administrative privileges
run 'wsl --mount \.\PHYSICALDRIVE2'
Powershell will say The disk \\.\PHYSICALDRIVE2 was attached from WSL2, but failed to mount (error code: -1). For more details, run 'dmesg' inside WSL2.

Expected behavior

The EXT4 partition to mount correctly allowing me to access it.

Actual behavior

EXT4 partition is attached but not mounted, causing me to not be able to access the contents.

The dmesg output is [ 0.008340] Microsoft 4.4.0-20270.1-Microsoft 4.4.35

[IAmV0id]

Nevermind, solved it by adding --partition 1 to the end. A bit odd considering the disk only has one partition though.

[IAmV0id]

The mounted partition does not show up under /mnt, reopening this issue.

[OneBlue]

Thanks for reporting this @A-Random-Lantern.

Also, to give some context on --partition: by default WSL attempts to mount the entire block device as if it was unpartitioned (ex: mount /dev/sda)

Can you please follow 7) and 8) in these instructions so we can have a look at the logs ?
Also, what if you try to access to access /mnt from wsl ? What's the output of ls /mnt/wsl ?

[IAmV0id]

Here's my logs
https://pastebin.com/nju2mxaM

And my feedback report.
https://aka.ms/AAaklz4

I tried ls /mnt/wsl to check earlier, all I got was "c" and "d"

[IAmV0id]

Sorry, accidentally closed the issue.

[OneBlue]

Thanks @A-Random-Lantern .
Unfortunately I don't see any repro logs in the feedback hub item.

Can you confirm that you followed the Start recording steps in the 'Recreate your problem' section, and if not, can you please publish another entry with a problem recording ?

[IAmV0id]

Sorry, here's the new link.

The G drive is my NTFS external drive by the way. https://aka.ms/AAamd0c

[OneBlue]

Thanks @A-Random-Lantern .

So if you're disk is ntfs, it's expected that wsl --mount --partition 1 fails because ntfs isn't supported by the linux kernel we ship.
From the documentation:

Only filesystems that are natively supported in the kernel can be mounted by wsl --mount. This means that it's not possible to use installed filesystem drivers (such as ntfs-3g for example) by calling wsl --mount.

In your case, the way to mount this disk would be to first attach it to WSL2 with: wsl --mount \\.\PHYSICALDRIVE2 --bare, and then mount it manually inside WSL2: mkdir -p /mnt/wsl/PHYSICALDRIVE2p1 && mount /dev/sdX1 /mnt/wsl/PHYSICALDRIVE2p1 (replace sdX1 with the block device matching your disk. You can use lsblk to view available block devices).

Also ntfs-3g needs to be installed in your distro for this to work.

What's interesting though, is that if your disk is ntfs, you should get an error message if you try to mount it. Can you show the output of wsl --mount \\.\PHYSICALDRIVE2 --partition 1 ? And, after running that, the output of dmesg and mount inside WSL2 ?

[IAmV0id]

Ah, the ntfs drive isn't the one I'm trying to mount. I was just clarifying that to avoid confusion, as there was no G drive in the original image above.

Sorry for any confusion caused by this, the current drive I'm trying to mount is EXT4

[OneBlue]

No problems. Can you share the output of the above three commands then ? That would help us locate the source of the issue.

[IAmV0id]

Sure, here you go.

Here's the output for powershell:
The disk \\.\PHYSICALDRIVE2 was successfully mounted under the name 'PHYSICALDRIVE2p1'. The mountpoint can be found under the path pointed to by the automount setting (default: /mnt/wsl). To unmount and detach the disk, run 'wsl --unmount \\.\PHYSICALDRIVE2'.

And here's the outputs in WSL:
[ 0.005170] Microsoft 4.4.0-20279.1-Microsoft 4.4.35 dmesg command

rootfs on / type wslfs (rw,noatime) none on /dev type tmpfs (rw,noatime,mode=755) sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,noatime) proc on /proc type proc (rw,nosuid,nodev,noexec,noatime) devpts on /dev/pts type devpts (rw,nosuid,noexec,noatime,gid=5,mode=620) none on /run type tmpfs (rw,nosuid,noexec,noatime,mode=755) none on /run/lock type tmpfs (rw,nosuid,nodev,noexec,noatime) none on /run/shm type tmpfs (rw,nosuid,nodev,noatime) none on /run/user type tmpfs (rw,nosuid,nodev,noexec,noatime,mode=755) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,relatime) tmpfs on /sys/fs/cgroup type tmpfs (rw,nosuid,nodev,noexec,relatime,mode=755) cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices) C:\ on /mnt/c type drvfs (rw,noatime,uid=1000,gid=1000,case=off) D:\ on /mnt/d type drvfs (rw,noatime,uid=1000,gid=1000,case=off) G:\ on /mnt/g type drvfs (rw,noatime,uid=1000,gid=1000,case=off) mount command

[OneBlue]

Interesting. Based on those logs, it looks like you're using WSL1, but wsl --mount is only supported in WSL2.

Do you have distros in both WSL1 and WSL2 ? (you can find that out by running wsl -l -v) ?

If you mount a disk, it's only accessible in WSL2 distros.

[IAmV0id]

Yeah, found the problem thanks to you. I installed the linux distro under WSL 1 since I haven't set the default to WSL 2. I just tried mounting again, the drive mounts correctly now and I can access it.

Closing the issue, sorry if this was a time waste haha.