4.20-stable review patch. If anyone has any objections, please let me know.
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From: J. Bruce Fields bfields@redhat.com
commit fdec6114ee1f0f43b1ad081ad8d46b23ba126d70 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/nfsd/nfs4proc.c | 2 -- 1 file changed, 2 deletions(-)
--- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -1016,8 +1016,6 @@ nfsd4_write(struct svc_rqst *rqstp, stru
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,