pynfs V3 ideas - WAS: [PATCH 5/9] nfsd: NFSv3 should allow zero length writes

On Fri, Dec 17, 2021 at 5:07 PM [off-list ref] wrote:

quoted

From: Trond Myklebust <redacted>

According to RFC1813: "If count is 0, the WRITE will succeed and
return a count of 0, barring errors due to permissions checking."

Yes, I'm surprised we're not already doing this right.

I wonder how far back this bug goes.

The svc.c code is from 8154ef2776aa "NFSD: Clean up legacy NFS WRITE
argument XDR decoders", but the behavior might predate that code.  The
nfsd_vfs_write() logic, I'm not sure I understand.

We have a pynfs test for the v4 case (WRT4), but I guess we must have nothing
testing the v3 case.

Hmm, need to try and remember this... I am slowly working on pnfs V3 test cases so I will try and make sure edge cases like this get tested.

Frank