Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 601bf33..5241114 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -39,6 +39,7 @@
 #include "state.h"
 #include "netns.h"
 #include "xdr4cb.h"
+#include "xdr4.h"
 
 #define NFSDDBG_FACILITY                NFSDDBG_PROC
 
@@ -59,16 +60,6 @@
 	int		status;
 };
 
-/*
- * Handle decode buffer overflows out-of-line.
- */
-static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
-{
-	dprintk("NFS: %s prematurely hit the end of our receive buffer. "
-		"Remaining buffer length is %tu words.\n",
-		func, xdr->end - xdr->p);
-}
-
 static __be32 *xdr_encode_empty_array(__be32 *p)
 {
 	*p++ = xdr_zero;
@@ -105,6 +96,7 @@
 	OP_CB_WANTS_CANCELLED		= 12,
 	OP_CB_NOTIFY_LOCK		= 13,
 	OP_CB_NOTIFY_DEVICEID		= 14,
+	OP_CB_OFFLOAD			= 15,
 	OP_CB_ILLEGAL			= 10044
 };
 
@@ -238,7 +230,6 @@
 	*status = nfs_cb_stat_to_errno(be32_to_cpup(p));
 	return 0;
 out_overflow:
-	print_overflow_msg(__func__, xdr);
 	return -EIO;
 out_unexpected:
 	dprintk("NFSD: Callback server returned operation %d but "
@@ -307,7 +298,6 @@
 	hdr->nops = be32_to_cpup(p);
 	return 0;
 out_overflow:
-	print_overflow_msg(__func__, xdr);
 	return -EIO;
 }
 
@@ -435,7 +425,6 @@
 	cb->cb_seq_status = status;
 	return status;
 out_overflow:
-	print_overflow_msg(__func__, xdr);
 	status = -EIO;
 	goto out;
 }
@@ -523,11 +512,9 @@
 	if (unlikely(status))
 		return status;
 
-	if (cb != NULL) {
-		status = decode_cb_sequence4res(xdr, cb);
-		if (unlikely(status || cb->cb_seq_status))
-			return status;
-	}
+	status = decode_cb_sequence4res(xdr, cb);
+	if (unlikely(status || cb->cb_seq_status))
+		return status;
 
 	return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
 }
@@ -615,11 +602,10 @@
 	if (unlikely(status))
 		return status;
 
-	if (cb) {
-		status = decode_cb_sequence4res(xdr, cb);
-		if (unlikely(status || cb->cb_seq_status))
-			return status;
-	}
+	status = decode_cb_sequence4res(xdr, cb);
+	if (unlikely(status || cb->cb_seq_status))
+		return status;
+
 	return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
 }
 #endif /* CONFIG_NFSD_PNFS */
@@ -674,15 +660,108 @@
 	if (unlikely(status))
 		return status;
 
-	if (cb) {
-		status = decode_cb_sequence4res(xdr, cb);
-		if (unlikely(status || cb->cb_seq_status))
-			return status;
-	}
+	status = decode_cb_sequence4res(xdr, cb);
+	if (unlikely(status || cb->cb_seq_status))
+		return status;
+
 	return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
 }
 
 /*
+ * struct write_response4 {
+ *	stateid4	wr_callback_id<1>;
+ *	length4		wr_count;
+ *	stable_how4	wr_committed;
+ *	verifier4	wr_writeverf;
+ * };
+ * union offload_info4 switch (nfsstat4 coa_status) {
+ *	case NFS4_OK:
+ *		write_response4	coa_resok4;
+ *	default:
+ *	length4		coa_bytes_copied;
+ * };
+ * struct CB_OFFLOAD4args {
+ *	nfs_fh4		coa_fh;
+ *	stateid4	coa_stateid;
+ *	offload_info4	coa_offload_info;
+ * };
+ */
+static void encode_offload_info4(struct xdr_stream *xdr,
+				 __be32 nfserr,
+				 const struct nfsd4_copy *cp)
+{
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 4);
+	*p++ = nfserr;
+	if (!nfserr) {
+		p = xdr_reserve_space(xdr, 4 + 8 + 4 + NFS4_VERIFIER_SIZE);
+		p = xdr_encode_empty_array(p);
+		p = xdr_encode_hyper(p, cp->cp_res.wr_bytes_written);
+		*p++ = cpu_to_be32(cp->cp_res.wr_stable_how);
+		p = xdr_encode_opaque_fixed(p, cp->cp_res.wr_verifier.data,
+					    NFS4_VERIFIER_SIZE);
+	} else {
+		p = xdr_reserve_space(xdr, 8);
+		/* We always return success if bytes were written */
+		p = xdr_encode_hyper(p, 0);
+	}
+}
+
+static void encode_cb_offload4args(struct xdr_stream *xdr,
+				   __be32 nfserr,
+				   const struct knfsd_fh *fh,
+				   const struct nfsd4_copy *cp,
+				   struct nfs4_cb_compound_hdr *hdr)
+{
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 4);
+	*p++ = cpu_to_be32(OP_CB_OFFLOAD);
+	encode_nfs_fh4(xdr, fh);
+	encode_stateid4(xdr, &cp->cp_res.cb_stateid);
+	encode_offload_info4(xdr, nfserr, cp);
+
+	hdr->nops++;
+}
+
+static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
+				    struct xdr_stream *xdr,
+				    const void *data)
+{
+	const struct nfsd4_callback *cb = data;
+	const struct nfsd4_copy *cp =
+		container_of(cb, struct nfsd4_copy, cp_cb);
+	struct nfs4_cb_compound_hdr hdr = {
+		.ident = 0,
+		.minorversion = cb->cb_clp->cl_minorversion,
+	};
+
+	encode_cb_compound4args(xdr, &hdr);
+	encode_cb_sequence4args(xdr, cb, &hdr);
+	encode_cb_offload4args(xdr, cp->nfserr, &cp->fh, cp, &hdr);
+	encode_cb_nops(&hdr);
+}
+
+static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
+				   struct xdr_stream *xdr,
+				   void *data)
+{
+	struct nfsd4_callback *cb = data;
+	struct nfs4_cb_compound_hdr hdr;
+	int status;
+
+	status = decode_cb_compound4res(xdr, &hdr);
+	if (unlikely(status))
+		return status;
+
+	status = decode_cb_sequence4res(xdr, cb);
+	if (unlikely(status || cb->cb_seq_status))
+		return status;
+
+	return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
+}
+/*
  * RPC procedure tables
  */
 #define PROC(proc, call, argtype, restype)				\
@@ -703,6 +782,7 @@
 	PROC(CB_LAYOUT,	COMPOUND,	cb_layout,	cb_layout),
 #endif
 	PROC(CB_NOTIFY_LOCK,	COMPOUND,	cb_notify_lock,	cb_notify_lock),
+	PROC(CB_OFFLOAD,	COMPOUND,	cb_offload,	cb_offload),
 };
 
 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
@@ -746,24 +826,23 @@
 	return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
 }
 
-static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
+static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 {
 	if (clp->cl_minorversion == 0) {
-		char *principal = clp->cl_cred.cr_targ_princ ?
-					clp->cl_cred.cr_targ_princ : "nfs";
-		struct rpc_cred *cred;
+		client->cl_principal = clp->cl_cred.cr_targ_princ ?
+			clp->cl_cred.cr_targ_princ : "nfs";
 
-		cred = rpc_lookup_machine_cred(principal);
-		if (!IS_ERR(cred))
-			get_rpccred(cred);
-		return cred;
+		return get_cred(rpc_machine_cred());
 	} else {
-		struct rpc_auth *auth = client->cl_auth;
-		struct auth_cred acred = {};
+		struct cred *kcred;
 
-		acred.uid = ses->se_cb_sec.uid;
-		acred.gid = ses->se_cb_sec.gid;
-		return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
+		kcred = prepare_kernel_cred(NULL);
+		if (!kcred)
+			return NULL;
+
+		kcred->uid = ses->se_cb_sec.uid;
+		kcred->gid = ses->se_cb_sec.gid;
+		return kcred;
 	}
 }
 
@@ -784,9 +863,10 @@
 		.program	= &cb_program,
 		.version	= 1,
 		.flags		= (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
+		.cred		= current_cred(),
 	};
 	struct rpc_clnt *client;
-	struct rpc_cred *cred;
+	const struct cred *cred;
 
 	if (clp->cl_minorversion == 0) {
 		if (!clp->cl_cred.cr_principal &&
@@ -816,9 +896,9 @@
 		return PTR_ERR(client);
 	}
 	cred = get_backchannel_cred(clp, client, ses);
-	if (IS_ERR(cred)) {
+	if (!cred) {
 		rpc_shutdown_client(client);
-		return PTR_ERR(cred);
+		return -ENOMEM;
 	}
 	clp->cl_cb_client = client;
 	clp->cl_cb_cred = cred;
@@ -926,8 +1006,9 @@
 	cb->cb_seq_status = 1;
 	cb->cb_status = 0;
 	if (minorversion) {
-		if (!nfsd41_cb_get_slot(clp, task))
+		if (!cb->cb_holds_slot && !nfsd41_cb_get_slot(clp, task))
 			return;
+		cb->cb_holds_slot = true;
 	}
 	rpc_call_start(task);
 }
@@ -948,12 +1029,15 @@
 		 * the submission code will error out, so we don't need to
 		 * handle that case here.
 		 */
-		if (task->tk_flags & RPC_TASK_KILLED)
+		if (RPC_SIGNALLED(task))
 			goto need_restart;
 
 		return true;
 	}
 
+	if (!cb->cb_holds_slot)
+		goto need_restart;
+
 	switch (cb->cb_seq_status) {
 	case 0:
 		/*
@@ -992,12 +1076,13 @@
 			cb->cb_seq_status);
 	}
 
+	cb->cb_holds_slot = false;
 	clear_bit(0, &clp->cl_cb_slot_busy);
 	rpc_wake_up_next(&clp->cl_cb_waitq);
 	dprintk("%s: freed slot, new seqid=%d\n", __func__,
 		clp->cl_cb_session->se_cb_seq_nr);
 
-	if (task->tk_flags & RPC_TASK_KILLED)
+	if (RPC_SIGNALLED(task))
 		goto need_restart;
 out:
 	return ret;
@@ -1033,10 +1118,11 @@
 		rpc_restart_call_prepare(task);
 		return;
 	case 1:
-		break;
-	case -1:
-		/* Network partition? */
-		nfsd4_mark_cb_down(clp, task->tk_status);
+		switch (task->tk_status) {
+		case -EIO:
+		case -ETIMEDOUT:
+			nfsd4_mark_cb_down(clp, task->tk_status);
+		}
 		break;
 	default:
 		BUG();
@@ -1116,7 +1202,7 @@
 	if (clp->cl_cb_client) {
 		rpc_shutdown_client(clp->cl_cb_client);
 		clp->cl_cb_client = NULL;
-		put_rpccred(clp->cl_cb_cred);
+		put_cred(clp->cl_cb_cred);
 		clp->cl_cb_cred = NULL;
 	}
 	if (clp->cl_cb_conn.cb_xprt) {
@@ -1199,6 +1285,7 @@
 	cb->cb_seq_status = 1;
 	cb->cb_status = 0;
 	cb->cb_need_restart = false;
+	cb->cb_holds_slot = false;
 }
 
 void nfsd4_run_cb(struct nfsd4_callback *cb)