Re: freezing on unmountin ext2fs USB device

On Sun, Nov 23, 2025 at 7:15 AM A FreeBSD User <freebsd@walstatt-de.de>
wrote:

> Hello,
>
> running FreeBSD 16.0-CURRENT #4 master-n282101-c8cf5a99f82b: Sun Nov 23
> 13:56:23 CET
> 2025 amd64 I'm running into a serious problem when mounting an ext2fs
> formated USB Flash
> device (512GB). The devince contains files written by a Linux system,
> mounting the USB Flash
> via extended4fs, the size of the written datafiles is > 128GB. Deleting
> those files larger
> than some 20GB results in an I/O error reported by FReeBSD (# sudo rm
> /mnt/USB/filename).
> Unmounting the ext2fs after deletion (sudo umount /mnt) results in a total
> freeze of the box.
> No crash, no core dump, nothing. I waited almost an hour hoping for
> recover. I have to
> physically switch off the box.
>
> I checked with other USB flash I have at hand, one Samsung 256 GB, ZFS -
> no problem, another
> 128GB, UFS, no problem and several much smaller (4 - 64GB) with FAT or UFS
> filesystems, all no
> problem.
>
> I can not figure out whether it is the USB flash drive itself, the size or
> the ext2fs itself
> causing the problem.
>
> Does anybody see similar problems or do have an tip to investigate without
> risking my box'
> health switching it on/off on failure?
>

I've not seen this on the smaller tests I've been able to run.

So can you share the error messages that you get when you say you get I/O
errors? I'd like to see if this is due to an error in ext2fs or on the USB
drive. It's kinda sounding a little like the particular USB is triggering
some kind of issue that at the very least we should work around. Given that
it's not happening on all ext2fs drives you try to access, I'm leaning
towards the drive, but you never know.

Thanks