[PATCH v6 04/14] nfsd: allow unrecognisable filehandle for foreign servers in COPY

[NeilBrown <neilb@ownmail.net>]

From: NeilBrown <neil@brown.name>

RFC-7862 acknowledges that a filehandle provided as the source of an
inter-server copy might result in NFS4ERR_STALE when given to PUTFH, and
gives guidance on how this error can be ignored (section 15.2.3).

NFS4ERR_BADHANDLE is also a possible error in this circumstance if the
foreign server is running a different implementation of NFS than the
current one.  This appears to be a simple omission in the RFC.

There can be no harm in delaying a BADHANDLE error in the same situation
where we already delay STALE errors, and no harm in sending a locally
"bad" handle to a foreign server to request a COPY.

So extend the test in nfsd4_putfh to also check for nfserr_badhandle.

Signed-off-by: NeilBrown <neil@brown.name>
---
 fs/nfsd/nfs4proc.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 112e62b6b9c6..ae34b816371c 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -693,7 +693,8 @@ nfsd4_putfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	       putfh->pf_fhlen);
 	ret = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_BYPASS_GSS);
 #ifdef CONFIG_NFSD_V4_2_INTER_SSC
-	if (ret == nfserr_stale && inter_copy_offload_enable) {
+	if ((ret == nfserr_badhandle || ret == nfserr_stale) &&
+	    inter_copy_offload_enable) {
 		struct nfsd4_compoundargs *args = rqstp->rq_argp;
 		struct nfsd4_compoundres *resp = rqstp->rq_resp;
 
@@ -713,7 +714,11 @@ nfsd4_putfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 			 *  NOT return NFS4ERR_STALE for either
 			 *  operation.
 			 * We limit this to when there is a COPY
-			 * in the COMPOUND.
+			 * in the COMPOUND, and extend it to
+			 * also ignore NFS4ERR_BADHANDLE despite the
+			 * RFC not requiring this.  If the remote
+			 * server is running a different NFS implementation,
+			 * NFS4ERR_BADHANDLE is a likely error.
 			 */
 			ret = 0;
 		}
-- 
2.50.0.107.gf914562f5916.dirty