[PATCH v5 04/11] nfsd: report correct error for attempt to use foreign filehandle

[NeilBrown <neilb@ownmail.net>]

From: NeilBrown <neil@brown.name>

A COMPOUND with
   PUTFH foreign filehandle
   SAVFH
   RESTOREFH
   some-op-that-uses-current_fh
   COPY

will report NFS4ERR_NOHANDLE for that 4th op as ALLOWED_WITHOUT_LOCAL_FH
is set and ->fh_dentry is NULL.  However that error is not correct.
NFS4ERR_STALE or NFS4ERR_BADHANDLE would be the correct error.

This patch saves the correct error and reports it when appropriate.

It is highly unlikely that a client would ever notice this difference as
the COMPOUND that would produce it is bizarre.  Maybe we don't need this
patch.

Signed-off-by: NeilBrown <neil@brown.name>
---
 fs/nfsd/nfs4proc.c | 4 +++-
 fs/nfsd/xdr4.h     | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index e6f8b5b907a9..e61b1ee6c8d8 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -712,6 +712,7 @@ nfsd4_putfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 			 * in the COMPOUND, and extend it to
 			 * NFS4ERR_BADHANDLE.
 			 */
+			cstate->saved_status = ret;
 			ret = 0;
 		}
 	}
@@ -2856,6 +2857,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
 	resp->tag = args->tag;
 	resp->rqstp = rqstp;
 	cstate->minorversion = args->minorversion;
+	cstate->saved_status = nfserr_nofilehandle;
 	fh_init(current_fh, NFS4_FHSIZE);
 	fh_init(save_fh, NFS4_FHSIZE);
 	/*
@@ -2907,7 +2909,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
 		}
 		if (!current_fh->fh_dentry) {
 			if (!(op->opdesc->op_flags & ALLOWED_WITHOUT_LOCAL_FH)) {
-				op->status = nfserr_nofilehandle;
+				op->status = cstate->saved_status;
 				goto encode_op;
 			}
 		} else if (current_fh->fh_export->ex_fslocs.migrated &&
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 3de8f4e07c49..bcaf631ec12d 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -187,10 +187,11 @@ struct nfsd4_compound_state {
 	struct nfsd4_session	*session;
 	struct nfsd4_slot	*slot;
 	int			data_offset;
-	bool                    spo_must_allowed;
+	bool			spo_must_allowed;
 	size_t			iovlen;
 	u32			minorversion;
 	__be32			status;
+	__be32			saved_status;
 	stateid_t	current_stateid;
 	stateid_t	save_stateid;
 	/* to indicate current and saved state id presents */
-- 
2.50.0.107.gf914562f5916.dirty