[linux-rpi] 6.6.13: NFS bug on rpi4

[ntova]

Hi,

I seem to have hit a bug in linux-rpi-6.6.13: Reading any big files from an NFS share stops at exactly the 4GB mark every time with an input/output error (according to `dd`). This can be worked around by downgrading to linux-rpi-6.1.68.
My desktop (currently running linux-6.6.8 (x86_64)) reads those files just fine over NFS.

This problem is probably further upstream, but I quickly wanted to document my findings, as I haven't found anything on the internet about this. If you can reproduce this, give me a heads up.
For tomorrow, I'll further investigate and maybe raise an issue upstream.

[graysky]

I haven't seen this myself on nfs4 shares/linux-rpi. Anything diagnostic in journalctl output? Is the bug triggered just with dd? How are you invoking it and why? What about a real-world file copy of something over 4 GB with rsync? An upstream issue might yield some helpful advice. You can also post to the official rpi forum, but will need more info to help narrow it down.

[ntova]

I'm sorry for the lack of detail in my previous post. My findings in more detail:

Reading files larger than 4GB on a NFS share seems is broken for me when reading beyond the first 4GB of the file. I first noticed this in Kodi, where movies would just stop somewhere in the middle. Reading with ffmpeg, cp, dd or just a plain open() and read() always returns an I/O error beyond 4GB.

There are no errors either in journalctl or dmesg on NFS server and client.

My NFS server is a fully updated ArchLinux. I could reproduce this with both ext4 and btrfs as underlying filesystem.

Later today I will take some time to test it with Raspberry Pi OS to see if I can reproduce this there, too.

[graysky]

Interesting... anything in the kodi.log (set it to debug mode).