# Gentoo on Hyper-V 2012 - Can't use ext4 filesystem

## eddy89

Hello,

I got a problem trying to use ext4 filesystem on hyper-v 3.0 (windows server 2012) virtual storage.

If I format the partition with ext3, it all works well.

If I format a partition with ext4, mkfs works good, but when I try to mount it, it stuks at the first ls on the mount point (or pressing [tab] in bash).

In dmesg I just can see the same message repeated many times:

```
[276146.411171] sd 1:0:0:1: [sdc]

[276146.411173] Sense Key : No Sense [current]

[276146.411177] sd 1:0:0:1: [sdc]

[276146.411179] Add. Sense: No additional sense information

[276146.414822] hv_storvsc vmbus_0_13: cmd 0x41 scsi status 0x2 srb status 0x6

```

 Until I detach the virtual hard disk from the virtual machine.

I got the same problem with the live cd, so I choosed to use ext3 for the root file system. I have the same problem with the kernel built from last gentoo sources (x86), using the included hyper-v drivers.

Ubuntu seems not to have this problems, and works good also with ext4.

Do you have any hints?

Thanks

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## geeksheik

The only thing that I can think of is that you don't have ext4 support compiled into the kernel.  I think you would still be able to format an ext4 partition in this case (since that's a user-space tool), but not mount it.

Check via:

 *Quote:*   

> cat /proc/filesystems | grep ext4
> 
>         ext4
> 
> 

 

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## eddy89

Thank you geeksheik for your reply,

but I surely have ext4 compiled into kernel, as mounting the partition works, but the error start on the first access (e.g. ls).

I'll ask to microsoft forums too, but since ubuntu has not this problem, it seems something related to gentoo kernel.

(btw. as I said, the same problem is with the latest gentoo live cd for installation)

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## geeksheik

Any progress?  I'm not familiar with the inner workings of ext4 (or any filesystem drive for that matter), but this is what I'd check:

The ext4 options in the kernel (accessed via 'make menuconfig' / File systems) are as follows:

```
<*> The Extended 4 (ext4) filesystem

[*]   Ext4 POSIX Access Control Lists

[*]   Ext4 Security Labels

[*]   EXT4 debugging support

```

I'd recommend enabling the ACL's and Security Labels in case an optional feature is causing you problems (though unlikely).  Also enable debugging support.  If it's still broken, you might have additional information to post on one of the kernel development forums.

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## meez

Same here. If I use ext4 as fs, after first access the kernel crashes (as hyperv guest).

Root partition is ext4 and working without problems. Ext3 is working without problems as additional disc.

Greetings,

Martin

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