NFSD add nfs4 inter ssc to nfsd4_copy

Given a universal address, mount the source server from the destination
server. Use an internal mount. Call the NFS client nfs42_ssc_open to
obtain the NFS struct file suitable for nfsd_copy_range.

Ability to do "inter" server-to-server depends on the an nfsd kernel
parameter "inter_copy_offload_enable".

Signed-off-by: Olga Kornievskaia <[e-mail]>

fs/nfsd/nfs4proc.c

···
 	while ((copy = nfsd4_get_copy(clp)) != NULL)
 		nfsd4_stop_copy(copy);
 }
+#ifdef CONFIG_NFSD_V4_2_INTER_SSC
+
+extern struct file *nfs42_ssc_open(struct vfsmount *ss_mnt,
+				   struct nfs_fh *src_fh,
+				   nfs4_stateid *stateid);
+extern void nfs42_ssc_close(struct file *filep);
+
+extern void nfs_sb_deactive(struct super_block *sb);
+
+#define NFSD42_INTERSSC_MOUNTOPS "vers=4.2,addr=%s,sec=sys"
+
+/**
+ * Support one copy source server for now.
+ */
+static __be32
+nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,
+		       struct vfsmount **mount)
+{
+	struct file_system_type *type;
+	struct vfsmount *ss_mnt;
+	struct nfs42_netaddr *naddr;
+	struct sockaddr_storage tmp_addr;
+	size_t tmp_addrlen, match_netid_len = 3;
+	char *startsep = "", *endsep = "", *match_netid = "tcp";
+	char *ipaddr, *dev_name, *raw_data;
+	int len, raw_len, status = -EINVAL;
+
+	naddr = &nss->u.nl4_addr;
+	tmp_addrlen = rpc_uaddr2sockaddr(SVC_NET(rqstp), naddr->addr,
+					 naddr->addr_len,
+					 (struct sockaddr *)&tmp_addr,
+					 sizeof(tmp_addr));
+	if (tmp_addrlen == 0)
+		goto out_err;
+
+	if (tmp_addr.ss_family == AF_INET6) {
+		startsep = "[";
+		endsep = "]";
+		match_netid = "tcp6";
+		match_netid_len = 4;
+	}
+
+	if (naddr->netid_len != match_netid_len ||
+		strncmp(naddr->netid, match_netid, naddr->netid_len))
+		goto out_err;
+
+	/* Construct the raw data for the vfs_kern_mount call */
+	len = RPC_MAX_ADDRBUFLEN + 1;
+	ipaddr = kzalloc(len, GFP_KERNEL);
+	if (!ipaddr)
+		goto out_err;
+
+	rpc_ntop((struct sockaddr *)&tmp_addr, ipaddr, len);
+
+	/* 2 for ipv6 endsep and startsep. 3 for ":/" and trailing '/0'*/
+
+	raw_len = strlen(NFSD42_INTERSSC_MOUNTOPS) + strlen(ipaddr);
+	raw_data = kzalloc(raw_len, GFP_KERNEL);
+	if (!raw_data)
+		goto out_free_ipaddr;
+
+	snprintf(raw_data, raw_len, NFSD42_INTERSSC_MOUNTOPS, ipaddr);
+
+	status = -ENODEV;
+	type = get_fs_type("nfs");
+	if (!type)
+		goto out_free_rawdata;
+
+	/* Set the server:<export> for the vfs_kern_mount call */
+	dev_name = kzalloc(len + 5, GFP_KERNEL);
+	if (!dev_name)
+		goto out_free_rawdata;
+	snprintf(dev_name, len + 5, "%s%s%s:/", startsep, ipaddr, endsep);
+
+	/* Use an 'internal' mount: SB_KERNMOUNT -> MNT_INTERNAL */
+	ss_mnt = vfs_kern_mount(type, SB_KERNMOUNT, dev_name, raw_data);
+	module_put(type->owner);
+	if (IS_ERR(ss_mnt))
+		goto out_free_devname;
+
+	status = 0;
+	*mount = ss_mnt;
+
+out_free_devname:
+	kfree(dev_name);
+out_free_rawdata:
+	kfree(raw_data);
+out_free_ipaddr:
+	kfree(ipaddr);
+out_err:
+	return status;
+}
+
+static void
+nfsd4_interssc_disconnect(struct vfsmount *ss_mnt)
+{
+	nfs_sb_deactive(ss_mnt->mnt_sb);
+	mntput(ss_mnt);
+}
+
+/**
+ * nfsd4_setup_inter_ssc
+ *
+ * Verify COPY destination stateid.
+ * Connect to the source server with NFSv4.1.
+ * Create the source struct file for nfsd_copy_range.
+ * Called with COPY cstate:
+ *    SAVED_FH: source filehandle
+ *    CURRENT_FH: destination filehandle
+ *
+ * Returns errno (not nfserrxxx)
+ */
+static __be32
+nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
+		      struct nfsd4_compound_state *cstate,
+		      struct nfsd4_copy *copy, struct vfsmount **mount)
+{
+	struct svc_fh *s_fh = NULL;
+	stateid_t *s_stid = &copy->cp_src_stateid;
+	__be32 status = -EINVAL;
+
+	/* Verify the destination stateid and set dst struct file*/
+	status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
+					    &copy->cp_dst_stateid,
+					    WR_STATE, &copy->nf_dst, NULL);
+	if (status)
+		goto out;
+
+	status = nfsd4_interssc_connect(&copy->cp_src, rqstp, mount);
+	if (status)
+		goto out;
+
+	s_fh = &cstate->save_fh;
+
+	copy->c_fh.size = s_fh->fh_handle.fh_size;
+	memcpy(copy->c_fh.data, &s_fh->fh_handle.fh_base, copy->c_fh.size);
+	copy->stateid.seqid = s_stid->si_generation;
+	memcpy(copy->stateid.other, (void *)&s_stid->si_opaque,
+	       sizeof(stateid_opaque_t));
+
+	status = 0;
+out:
+	return status;
+}
+
+static void
+nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct nfsd_file *src,
+			struct nfsd_file *dst)
+{
+	nfs42_ssc_close(src->nf_file);
+	nfsd_file_put(src);
+	nfsd_file_put(dst);
+	mntput(ss_mnt);
+}
+
+#else /* CONFIG_NFSD_V4_2_INTER_SSC */
+
+static __be32
+nfsd4_setup_inter_ssc(struct svc_rqst *rqstp,
+		      struct nfsd4_compound_state *cstate,
+		      struct nfsd4_copy *copy,
+		      struct vfsmount **mount)
+{
+	*mount = NULL;
+	return -EINVAL;
+}
+
+static void
+nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct nfsd_file *src,
+			struct nfsd_file *dst)
+{
+}
+
+static void
+nfsd4_interssc_disconnect(struct vfsmount *ss_mnt)
+{
+}
+
+static struct file *nfs42_ssc_open(struct vfsmount *ss_mnt,
+				   struct nfs_fh *src_fh,
+				   nfs4_stateid *stateid)
+{
+	return NULL;
+}
+#endif /* CONFIG_NFSD_V4_2_INTER_SSC */
+
+static __be32
+nfsd4_setup_intra_ssc(struct svc_rqst *rqstp,
+		      struct nfsd4_compound_state *cstate,
+		      struct nfsd4_copy *copy)
+{
+	return nfsd4_verify_copy(rqstp, cstate, &copy->cp_src_stateid,
+				 &copy->nf_src, &copy->cp_dst_stateid,
+				 &copy->nf_dst);
+}
+
+static void
+nfsd4_cleanup_intra_ssc(struct nfsd_file *src, struct nfsd_file *dst)
+{
+	nfsd_file_put(src);
+	nfsd_file_put(dst);
+}
 
 static void nfsd4_cb_offload_release(struct nfsd4_callback *cb)
 {
···
 		status = nfs_ok;
 	}
 
-	nfsd_file_put(copy->nf_src);
-	nfsd_file_put(copy->nf_dst);
+	if (!copy->cp_intra) /* Inter server SSC */
+		nfsd4_cleanup_inter_ssc(copy->ss_mnt, copy->nf_src,
+					copy->nf_dst);
+	else
+		nfsd4_cleanup_intra_ssc(copy->nf_src, copy->nf_dst);
+
 	return status;
 }
 
-static void dup_copy_fields(struct nfsd4_copy *src, struct nfsd4_copy *dst)
+static int dup_copy_fields(struct nfsd4_copy *src, struct nfsd4_copy *dst)
 {
 	dst->cp_src_pos = src->cp_src_pos;
 	dst->cp_dst_pos = src->cp_dst_pos;
···
 	memcpy(&dst->fh, &src->fh, sizeof(src->fh));
 	dst->cp_clp = src->cp_clp;
 	dst->nf_dst = nfsd_file_get(src->nf_dst);
-	dst->nf_src = nfsd_file_get(src->nf_src);
+	dst->cp_intra = src->cp_intra;
+	if (src->cp_intra) /* for inter, file_src doesn't exist yet */
+		dst->nf_src = nfsd_file_get(src->nf_src);
+
 	memcpy(&dst->cp_stateid, &src->cp_stateid, sizeof(src->cp_stateid));
+	memcpy(&dst->cp_src, &src->cp_src, sizeof(struct nl4_server));
+	memcpy(&dst->stateid, &src->stateid, sizeof(src->stateid));
+	memcpy(&dst->c_fh, &src->c_fh, sizeof(src->c_fh));
+	dst->ss_mnt = src->ss_mnt;
+
+	return 0;
 }
 
 static void cleanup_async_copy(struct nfsd4_copy *copy)
···
 	struct nfsd4_copy *copy = (struct nfsd4_copy *)data;
 	struct nfsd4_copy *cb_copy;
 
+	if (!copy->cp_intra) { /* Inter server SSC */
+		copy->nf_src = kzalloc(sizeof(struct nfsd_file), GFP_KERNEL);
+		if (!copy->nf_src) {
+			copy->nfserr = nfserr_serverfault;
+			nfsd4_interssc_disconnect(copy->ss_mnt);
+			goto do_callback;
+		}
+		copy->nf_src->nf_file = nfs42_ssc_open(copy->ss_mnt, &copy->c_fh,
+					      &copy->stateid);
+		if (IS_ERR(copy->nf_src->nf_file)) {
+			kfree(copy->nf_src);
+			copy->nfserr = nfserr_offload_denied;
+			nfsd4_interssc_disconnect(copy->ss_mnt);
+			goto do_callback;
+		}
+	}
+
 	copy->nfserr = nfsd4_do_copy(copy, 0);
+do_callback:
 	cb_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
 	if (!cb_copy)
 		goto out;
···
 			&nfsd4_cb_offload_ops, NFSPROC4_CLNT_CB_OFFLOAD);
 	nfsd4_run_cb(&cb_copy->cp_cb);
 out:
+	if (!copy->cp_intra)
+		kfree(copy->nf_src);
 	cleanup_async_copy(copy);
 	return 0;
 }
···
 	__be32 status;
 	struct nfsd4_copy *async_copy = NULL;
 
-	status = nfsd4_verify_copy(rqstp, cstate, &copy->cp_src_stateid,
-				   &copy->nf_src, &copy->cp_dst_stateid,
-				   &copy->nf_dst);
-	if (status)
-		goto out;
+	if (!copy->cp_intra) { /* Inter server SSC */
+		if (!inter_copy_offload_enable || copy->cp_synchronous) {
+			status = nfserr_notsupp;
+			goto out;
+		}
+		status = nfsd4_setup_inter_ssc(rqstp, cstate, copy,
+				&copy->ss_mnt);
+		if (status)
+			return nfserr_offload_denied;
+	} else {
+		status = nfsd4_setup_intra_ssc(rqstp, cstate, copy);
+		if (status)
+			return status;
+	}
 
 	copy->cp_clp = cstate->clp;
 	memcpy(&copy->fh, &cstate->current_fh.fh_handle,
···
 		status = nfserrno(-ENOMEM);
 		async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
 		if (!async_copy)
-			goto out;
-		if (!nfs4_init_copy_state(nn, copy)) {
-			kfree(async_copy);
-			goto out;
-		}
+			goto out_err;
+		if (!nfs4_init_copy_state(nn, copy))
+			goto out_err;
 		refcount_set(&async_copy->refcount, 1);
 		memcpy(&copy->cp_res.cb_stateid, &copy->cp_stateid,
 			sizeof(copy->cp_stateid));
-		dup_copy_fields(copy, async_copy);
+		status = dup_copy_fields(copy, async_copy);
+		if (status)
+			goto out_err;
 		async_copy->copy_task = kthread_create(nfsd4_do_async_copy,
 				async_copy, "%s", "copy thread");
 		if (IS_ERR(async_copy->copy_task))
···
 		spin_unlock(&async_copy->cp_clp->async_lock);
 		wake_up_process(async_copy->copy_task);
 		status = nfs_ok;
-	} else
+	} else {
 		status = nfsd4_do_copy(copy, 1);
+	}
 out:
 	return status;
 out_err:
 	if (async_copy)
 		cleanup_async_copy(async_copy);
+	status = nfserrno(-ENOMEM);
+	if (!copy->cp_intra)
+		nfsd4_interssc_disconnect(copy->ss_mnt);
 	goto out;
 }
 
···
 
 	spin_lock(&clp->async_lock);
 	list_for_each_entry(copy, &clp->async_copies, copies) {
-		if (memcmp(&copy->cp_stateid, stateid, NFS4_STATEID_SIZE))
+		if (memcmp(&copy->cp_stateid.stid, stateid, NFS4_STATEID_SIZE))
 			continue;
 		refcount_inc(&copy->refcount);
 		spin_unlock(&clp->async_lock);
···
 		     union nfsd4_op_u *u)
 {
 	struct nfsd4_offload_status *os = &u->offload_status;
-	__be32 status = 0;
 	struct nfsd4_copy *copy;
 	struct nfs4_client *clp = cstate->clp;
 
 	copy = find_async_copy(clp, &os->stateid);
-	if (copy)
-		nfsd4_stop_copy(copy);
-	else
-		status = nfserr_bad_stateid;
+	if (!copy) {
+		struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 
-	return status;
+		return manage_cpntf_state(nn, &os->stateid, clp, NULL);
+	} else
+		nfsd4_stop_copy(copy);
+
+	return nfs_ok;
 }
 
 static __be32

fs/nfsd/nfs4state.c

···
  * copy stateid. Look up the copy notify stateid from the
  * idr structure and take a reference on it.
  */
-static __be32 _find_cpntf_state(struct nfsd_net *nn, stateid_t *st,
-		     struct nfs4_cpntf_state **cps)
+__be32 manage_cpntf_state(struct nfsd_net *nn, stateid_t *st,
+			  struct nfs4_client *clp,
+			  struct nfs4_cpntf_state **cps)
 {
 	copy_stateid_t *cps_t;
 	struct nfs4_cpntf_state *state = NULL;
···
 				     cp_stateid);
 		if (state->cp_stateid.sc_type != NFS4_COPYNOTIFY_STID)
 			return nfserr_bad_stateid;
-		refcount_inc(&state->cp_stateid.sc_count);
+		if (!clp)
+			refcount_inc(&state->cp_stateid.sc_count);
+		else
+			_free_cpntf_state_locked(nn, state);
 	}
 	spin_unlock(&nn->s2s_cp_lock);
 	if (!state)
 		return nfserr_bad_stateid;
-	*cps = state;
+	if (!clp && state)
+		*cps = state;
 	return 0;
 }
 
···
 	struct nfs4_cpntf_state *cps = NULL;
 	struct nfsd4_compound_state cstate;
 
-	status = _find_cpntf_state(nn, st, &cps);
+	status = manage_cpntf_state(nn, st, NULL, &cps);
 	if (status)
 		return status;
 

fs/nfsd/nfssvc.c

···
 
 #define NFSDDBG_FACILITY	NFSDDBG_SVC
 
+bool inter_copy_offload_enable;
+EXPORT_SYMBOL_GPL(inter_copy_offload_enable);
+module_param(inter_copy_offload_enable, bool, 0644);
+MODULE_PARM_DESC(inter_copy_offload_enable,
+		 "Enable inter server to server copy offload. Default: false");
+
 extern struct svc_program	nfsd_program;
 static int			nfsd(void *vrqstp);
 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)

fs/nfsd/state.h

···
 find_async_copy(struct nfs4_client *clp, stateid_t *staetid);
 extern void nfs4_put_cpntf_state(struct nfsd_net *nn,
 				 struct nfs4_cpntf_state *cps);
+extern __be32 manage_cpntf_state(struct nfsd_net *nn, stateid_t *st,
+				 struct nfs4_client *clp,
+				 struct nfs4_cpntf_state **cps);
 static inline void get_nfs4_file(struct nfs4_file *fi)
 {
 	refcount_inc(&fi->fi_ref);

fs/nfsd/xdr4.h

···
 	struct task_struct	*copy_task;
 	refcount_t		refcount;
 	bool			stopped;
+
+	struct vfsmount		*ss_mnt;
+	struct nfs_fh		c_fh;
+	nfs4_stateid		stateid;
 };
+extern bool inter_copy_offload_enable;
 
 struct nfsd4_seek {
 	/* request */