Linux 6.10 Is Disabling NFS v2 Client Support By Default

Following the NFS server changes from a few days ago for Linux 6.10 that brought optimizations and prepping for the new "nfsdctl" utility, the Network File System client changes have been submitted and merged for this new kernel.

The NFS client changes were sent out today and subsequently merged for Linux 6.10 Git. With this pull the atomic_open API is now used for NFS v3 to handle O_TRUNC correctly. This addresses an issue where multiple clients mount the same directory and truncating the file on open (O_TRUNC) can lead to unexpected conditions. The Network File System client changes also include a number of bug fixes and other alterations.

The other item worth pointing out is that by default the NFS v2 client support is no longer enabled.

There still is the NFS_V2 Kconfig option for enabling NFS protocol version 2 support, but it's now being disabled by default. The change comes in via Netapp after the nfs-utils' mount.nfs command dropped NFS v2 support in December of 2021. So it's about time the kernel support is disabled by default too.

NFS v2 dates back to 1989 while NFS v3 and NFS v4 are both over two decades old already and common place. It's time for NFS v2 to retire. The kernel code remains in place though should anyone really need it.

The full list of NFS client changes for Linux 6.10 can be found via this pull.