Zero-length writes are legal; from 5661 section 18.32.3: "If the count
is zero, the WRITE will succeed and return a count of zero subject to
permissions checking".
This check is unnecessary and is causing zero-length reads to return
EINVAL.
Cc: stable@vger.kernel.org
Fixes: 3fd9557aec91 "NFSD: Refactor the generic write vector fill helper"
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
nvecs = svc_fill_write_vector(rqstp, write->wr_pagelist,
&write->wr_head, write->wr_buflen);
- if (!nvecs)
- return nfserr_io;
WARN_ON_ONCE(nvecs > ARRAY_SIZE(rqstp->rq_vec));
status = nfsd_vfs_write(rqstp, &cstate->current_fh, filp,