[mirror_ubuntu-bionic-kernel.git] / include / linux / pnfs_osd_xdr.h

/*
 *  pNFS-osd on-the-wire data structures
 *
 *  Copyright (C) 2007 Panasas Inc. [year of first publication]
 *  All rights reserved.
 *
 *  Benny Halevy <bhalevy@panasas.com>
 *  Boaz Harrosh <bharrosh@panasas.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  See the file COPYING included with this distribution for more details.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the Panasas company nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef __PNFS_OSD_XDR_H__
#define __PNFS_OSD_XDR_H__

#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <scsi/osd_protocol.h>

#define PNFS_OSD_OSDNAME_MAXSIZE 256

/*
 * draft-ietf-nfsv4-minorversion-22
 * draft-ietf-nfsv4-pnfs-obj-12
 */

/* Layout Structure */

enum pnfs_osd_raid_algorithm4 {
	PNFS_OSD_RAID_0		= 1,
	PNFS_OSD_RAID_4		= 2,
	PNFS_OSD_RAID_5		= 3,
	PNFS_OSD_RAID_PQ	= 4     /* Reed-Solomon P+Q */
};

/*   struct pnfs_osd_data_map4 {
 *       uint32_t                    odm_num_comps;
 *       length4                     odm_stripe_unit;
 *       uint32_t                    odm_group_width;
 *       uint32_t                    odm_group_depth;
 *       uint32_t                    odm_mirror_cnt;
 *       pnfs_osd_raid_algorithm4    odm_raid_algorithm;
 *   };
 */
struct pnfs_osd_data_map {
	u32	odm_num_comps;
	u64	odm_stripe_unit;
	u32	odm_group_width;
	u32	odm_group_depth;
	u32	odm_mirror_cnt;
	u32	odm_raid_algorithm;
};

/*   struct pnfs_osd_objid4 {
 *       deviceid4       oid_device_id;
 *       uint64_t        oid_partition_id;
 *       uint64_t        oid_object_id;
 *   };
 */
struct pnfs_osd_objid {
	struct nfs4_deviceid	oid_device_id;
	u64			oid_partition_id;
	u64			oid_object_id;
};

/* For printout. I use:
 * kprint("dev(%llx:%llx)", _DEVID_LO(pointer), _DEVID_HI(pointer));
 * BE style
 */
#define _DEVID_LO(oid_device_id) \
	(unsigned long long)be64_to_cpup((__be64 *)(oid_device_id)->data)

#define _DEVID_HI(oid_device_id) \
	(unsigned long long)be64_to_cpup(((__be64 *)(oid_device_id)->data) + 1)

static inline int
pnfs_osd_objid_xdr_sz(void)
{
	return (NFS4_DEVICEID4_SIZE / 4) + 2 + 2;
}

enum pnfs_osd_version {
	PNFS_OSD_MISSING              = 0,
	PNFS_OSD_VERSION_1            = 1,
	PNFS_OSD_VERSION_2            = 2
};

struct pnfs_osd_opaque_cred {
	u32 cred_len;
	void *cred;
};

enum pnfs_osd_cap_key_sec {
	PNFS_OSD_CAP_KEY_SEC_NONE     = 0,
	PNFS_OSD_CAP_KEY_SEC_SSV      = 1,
};

/*   struct pnfs_osd_object_cred4 {
 *       pnfs_osd_objid4         oc_object_id;
 *       pnfs_osd_version4       oc_osd_version;
 *       pnfs_osd_cap_key_sec4   oc_cap_key_sec;
 *       opaque                  oc_capability_key<>;
 *       opaque                  oc_capability<>;
 *   };
 */
struct pnfs_osd_object_cred {
	struct pnfs_osd_objid		oc_object_id;
	u32				oc_osd_version;
	u32				oc_cap_key_sec;
	struct pnfs_osd_opaque_cred	oc_cap_key;
	struct pnfs_osd_opaque_cred	oc_cap;
};

/*   struct pnfs_osd_layout4 {
 *       pnfs_osd_data_map4      olo_map;
 *       uint32_t                olo_comps_index;
 *       pnfs_osd_object_cred4   olo_components<>;
 *   };
 */
struct pnfs_osd_layout {
	struct pnfs_osd_data_map	olo_map;
	u32				olo_comps_index;
	u32				olo_num_comps;
	struct pnfs_osd_object_cred	*olo_comps;
};

/* Device Address */
enum pnfs_osd_targetid_type {
	OBJ_TARGET_ANON = 1,
	OBJ_TARGET_SCSI_NAME = 2,
	OBJ_TARGET_SCSI_DEVICE_ID = 3,
};

/*   union pnfs_osd_targetid4 switch (pnfs_osd_targetid_type4 oti_type) {
 *       case OBJ_TARGET_SCSI_NAME:
 *           string              oti_scsi_name<>;
 *
 *       case OBJ_TARGET_SCSI_DEVICE_ID:
 *           opaque              oti_scsi_device_id<>;
 *
 *       default:
 *           void;
 *   };
 *
 *   union pnfs_osd_targetaddr4 switch (bool ota_available) {
 *       case TRUE:
 *           netaddr4            ota_netaddr;
 *       case FALSE:
 *           void;
 *   };
 *
 *   struct pnfs_osd_deviceaddr4 {
 *       pnfs_osd_targetid4      oda_targetid;
 *       pnfs_osd_targetaddr4    oda_targetaddr;
 *       uint64_t                oda_lun;
 *       opaque                  oda_systemid<>;
 *       pnfs_osd_object_cred4   oda_root_obj_cred;
 *       opaque                  oda_osdname<>;
 *   };
 */
struct pnfs_osd_targetid {
	u32				oti_type;
	struct nfs4_string		oti_scsi_device_id;
};

enum { PNFS_OSD_TARGETID_MAX = 1 + PNFS_OSD_OSDNAME_MAXSIZE / 4 };

/*   struct netaddr4 {
 *       // see struct rpcb in RFC1833
 *       string r_netid<>;    // network id
 *       string r_addr<>;     // universal address
 *   };
 */
struct pnfs_osd_net_addr {
	struct nfs4_string	r_netid;
	struct nfs4_string	r_addr;
};

struct pnfs_osd_targetaddr {
	u32				ota_available;
	struct pnfs_osd_net_addr	ota_netaddr;
};

enum {
	NETWORK_ID_MAX = 16 / 4,
	UNIVERSAL_ADDRESS_MAX = 64 / 4,
	PNFS_OSD_TARGETADDR_MAX = 3 +  NETWORK_ID_MAX + UNIVERSAL_ADDRESS_MAX,
};

struct pnfs_osd_deviceaddr {
	struct pnfs_osd_targetid	oda_targetid;
	struct pnfs_osd_targetaddr	oda_targetaddr;
	u8				oda_lun[8];
	struct nfs4_string		oda_systemid;
	struct pnfs_osd_object_cred	oda_root_obj_cred;
	struct nfs4_string		oda_osdname;
};

enum {
	ODA_OSDNAME_MAX = PNFS_OSD_OSDNAME_MAXSIZE / 4,
	PNFS_OSD_DEVICEADDR_MAX =
		PNFS_OSD_TARGETID_MAX + PNFS_OSD_TARGETADDR_MAX +
		2 /*oda_lun*/ +
		1 + OSD_SYSTEMID_LEN +
		1 + ODA_OSDNAME_MAX,
};

/* LAYOUTCOMMIT: layoutupdate */

/*   union pnfs_osd_deltaspaceused4 switch (bool dsu_valid) {
 *       case TRUE:
 *           int64_t     dsu_delta;
 *       case FALSE:
 *           void;
 *   };
 *
 *   struct pnfs_osd_layoutupdate4 {
 *       pnfs_osd_deltaspaceused4    olu_delta_space_used;
 *       bool                        olu_ioerr_flag;
 *   };
 */
struct pnfs_osd_layoutupdate {
	u32	dsu_valid;
	s64	dsu_delta;
	u32	olu_ioerr_flag;
};

/* LAYOUTRETURN: I/O Rrror Report */

enum pnfs_osd_errno {
	PNFS_OSD_ERR_EIO		= 1,
	PNFS_OSD_ERR_NOT_FOUND		= 2,
	PNFS_OSD_ERR_NO_SPACE		= 3,
	PNFS_OSD_ERR_BAD_CRED		= 4,
	PNFS_OSD_ERR_NO_ACCESS		= 5,
	PNFS_OSD_ERR_UNREACHABLE	= 6,
	PNFS_OSD_ERR_RESOURCE		= 7
};

/*   struct pnfs_osd_ioerr4 {
 *       pnfs_osd_objid4     oer_component;
 *       length4             oer_comp_offset;
 *       length4             oer_comp_length;
 *       bool                oer_iswrite;
 *       pnfs_osd_errno4     oer_errno;
 *   };
 */
struct pnfs_osd_ioerr {
	struct pnfs_osd_objid	oer_component;
	u64			oer_comp_offset;
	u64			oer_comp_length;
	u32			oer_iswrite;
	u32			oer_errno;
};

/* OSD XDR API */
/* Layout helpers */
/* Layout decoding is done in two parts:
 * 1. First Call pnfs_osd_xdr_decode_layout_map to read in only the header part
 *    of the layout. @iter members need not be initialized.
 *    Returned:
 *             @layout members are set. (@layout->olo_comps set to NULL).
 *
 *             Zero on success, or negative error if passed xdr is broken.
 *
 * 2. 2nd Call pnfs_osd_xdr_decode_layout_comp() in a loop until it returns
 *    false, to decode the next component.
 *    Returned:
 *       true if there is more to decode or false if we are done or error.
 *
 * Example:
 *	struct pnfs_osd_xdr_decode_layout_iter iter;
 *	struct pnfs_osd_layout layout;
 *	struct pnfs_osd_object_cred comp;
 *	int status;
 *
 *	status = pnfs_osd_xdr_decode_layout_map(&layout, &iter, xdr);
 *	if (unlikely(status))
 *		goto err;
 *	while(pnfs_osd_xdr_decode_layout_comp(&comp, &iter, xdr, &status)) {
 *		// All of @comp strings point to inside the xdr_buffer
 *		// or scrach buffer. Copy them out to user memory eg.
 *		copy_single_comp(dest_comp++, &comp);
 *	}
 *	if (unlikely(status))
 *		goto err;
 */

struct pnfs_osd_xdr_decode_layout_iter {
	unsigned total_comps;
	unsigned decoded_comps;
};

extern int pnfs_osd_xdr_decode_layout_map(struct pnfs_osd_layout *layout,
	struct pnfs_osd_xdr_decode_layout_iter *iter, struct xdr_stream *xdr);

extern bool pnfs_osd_xdr_decode_layout_comp(struct pnfs_osd_object_cred *comp,
	struct pnfs_osd_xdr_decode_layout_iter *iter, struct xdr_stream *xdr,
	int *err);

/* Device Info helpers */

/* Note: All strings inside @deviceaddr point to space inside @p.
 * @p should stay valid while @deviceaddr is in use.
 */
extern void pnfs_osd_xdr_decode_deviceaddr(
	struct pnfs_osd_deviceaddr *deviceaddr, __be32 *p);

/* layoutupdate (layout_commit) xdr helpers */
extern int
pnfs_osd_xdr_encode_layoutupdate(struct xdr_stream *xdr,
				 struct pnfs_osd_layoutupdate *lou);

/* osd_ioerror encoding/decoding (layout_return) */
/* Client */
extern __be32 *pnfs_osd_xdr_ioerr_reserve_space(struct xdr_stream *xdr);
extern void pnfs_osd_xdr_encode_ioerr(__be32 *p, struct pnfs_osd_ioerr *ioerr);

#endif /* __PNFS_OSD_XDR_H__ */
Commit	Line	Data
38b7c401 BH	1	/*
	2	* pNFS-osd on-the-wire data structures
	3	*
	4	* Copyright (C) 2007 Panasas Inc. [year of first publication]
	5	* All rights reserved.
	6	*
	7	* Benny Halevy <bhalevy@panasas.com>
	8	* Boaz Harrosh <bharrosh@panasas.com>
	9	*
	10	* This program is free software; you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License version 2
	12	* See the file COPYING included with this distribution for more details.
	13	*
	14	* Redistribution and use in source and binary forms, with or without
	15	* modification, are permitted provided that the following conditions
	16	* are met:
	17	*
	18	* 1. Redistributions of source code must retain the above copyright
	19	* notice, this list of conditions and the following disclaimer.
	20	* 2. Redistributions in binary form must reproduce the above copyright
	21	* notice, this list of conditions and the following disclaimer in the
	22	* documentation and/or other materials provided with the distribution.
	23	* 3. Neither the name of the Panasas company nor the names of its
	24	* contributors may be used to endorse or promote products derived
	25	* from this software without specific prior written permission.
	26	*
	27	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
	28	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	29	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	30	* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	31	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	32	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	33	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
	34	* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	35	* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	36	* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	37	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	38	*/
	39	#ifndef __PNFS_OSD_XDR_H__
	40	#define __PNFS_OSD_XDR_H__
	41
	42	#include <linux/nfs_fs.h>
	43	#include <linux/nfs_page.h>
	44	#include <scsi/osd_protocol.h>
	45
	46	#define PNFS_OSD_OSDNAME_MAXSIZE 256
	47
	48	/*
	49	* draft-ietf-nfsv4-minorversion-22
	50	* draft-ietf-nfsv4-pnfs-obj-12
	51	*/
	52
	53	/* Layout Structure */
	54
	55	enum pnfs_osd_raid_algorithm4 {
	56	PNFS_OSD_RAID_0 = 1,
	57	PNFS_OSD_RAID_4 = 2,
	58	PNFS_OSD_RAID_5 = 3,
	59	PNFS_OSD_RAID_PQ = 4 /* Reed-Solomon P+Q */
	60	};
	61
	62	/* struct pnfs_osd_data_map4 {
	63	* uint32_t odm_num_comps;
	64	* length4 odm_stripe_unit;
65	* uint32_t odm_group_width;
66	* uint32_t odm_group_depth;
67	* uint32_t odm_mirror_cnt;
68	* pnfs_osd_raid_algorithm4 odm_raid_algorithm;
69	* };
70	*/
71	struct pnfs_osd_data_map {
72	u32 odm_num_comps;
73	u64 odm_stripe_unit;
74	u32 odm_group_width;
75	u32 odm_group_depth;
76	u32 odm_mirror_cnt;
77	u32 odm_raid_algorithm;
78	};
79
80	/* struct pnfs_osd_objid4 {
81	* deviceid4 oid_device_id;
82	* uint64_t oid_partition_id;
83	* uint64_t oid_object_id;
84	* };
85	*/
86	struct pnfs_osd_objid {
87	struct nfs4_deviceid oid_device_id;
88	u64 oid_partition_id;
89	u64 oid_object_id;
90	};
91
92	/* For printout. I use:
93	* kprint("dev(%llx:%llx)", _DEVID_LO(pointer), _DEVID_HI(pointer));
94	* BE style
95	*/
96	#define _DEVID_LO(oid_device_id) \
97	(unsigned long long)be64_to_cpup((__be64 *)(oid_device_id)->data)
98
99	#define _DEVID_HI(oid_device_id) \
100	(unsigned long long)be64_to_cpup(((__be64 *)(oid_device_id)->data) + 1)
101
102	static inline int
103	pnfs_osd_objid_xdr_sz(void)
104	{
105	return (NFS4_DEVICEID4_SIZE / 4) + 2 + 2;
106	}
107
108	enum pnfs_osd_version {
109	PNFS_OSD_MISSING = 0,
110	PNFS_OSD_VERSION_1 = 1,
111	PNFS_OSD_VERSION_2 = 2
112	};
113
114	struct pnfs_osd_opaque_cred {
115	u32 cred_len;
116	void *cred;
117	};
118
119	enum pnfs_osd_cap_key_sec {
120	PNFS_OSD_CAP_KEY_SEC_NONE = 0,
121	PNFS_OSD_CAP_KEY_SEC_SSV = 1,
122	};
123
124	/* struct pnfs_osd_object_cred4 {
125	* pnfs_osd_objid4 oc_object_id;
126	* pnfs_osd_version4 oc_osd_version;
127	* pnfs_osd_cap_key_sec4 oc_cap_key_sec;
128	* opaque oc_capability_key<>;
129	* opaque oc_capability<>;
130	* };
131	*/
132	struct pnfs_osd_object_cred {
133	struct pnfs_osd_objid oc_object_id;
134	u32 oc_osd_version;
135	u32 oc_cap_key_sec;
136	struct pnfs_osd_opaque_cred oc_cap_key;
137	struct pnfs_osd_opaque_cred oc_cap;
138	};
139
140	/* struct pnfs_osd_layout4 {
141	* pnfs_osd_data_map4 olo_map;
142	* uint32_t olo_comps_index;
143	* pnfs_osd_object_cred4 olo_components<>;
144	* };
145	*/
146	struct pnfs_osd_layout {
147	struct pnfs_osd_data_map olo_map;
148	u32 olo_comps_index;
149	u32 olo_num_comps;
150	struct pnfs_osd_object_cred *olo_comps;
151	};
152
153	/* Device Address */
154	enum pnfs_osd_targetid_type {
155	OBJ_TARGET_ANON = 1,
156	OBJ_TARGET_SCSI_NAME = 2,
157	OBJ_TARGET_SCSI_DEVICE_ID = 3,
158	};
159
160	/* union pnfs_osd_targetid4 switch (pnfs_osd_targetid_type4 oti_type) {
161	* case OBJ_TARGET_SCSI_NAME:
162	* string oti_scsi_name<>;
163	*
164	* case OBJ_TARGET_SCSI_DEVICE_ID:
165	* opaque oti_scsi_device_id<>;
166	*
167	* default:
168	* void;
169	* };
170	*
171	* union pnfs_osd_targetaddr4 switch (bool ota_available) {
172	* case TRUE:
173	* netaddr4 ota_netaddr;
174	* case FALSE:
175	* void;
176	* };
177	*
178	* struct pnfs_osd_deviceaddr4 {
179	* pnfs_osd_targetid4 oda_targetid;
180	* pnfs_osd_targetaddr4 oda_targetaddr;
181	* uint64_t oda_lun;
182	* opaque oda_systemid<>;
183	* pnfs_osd_object_cred4 oda_root_obj_cred;
184	* opaque oda_osdname<>;
185	* };
186	*/
187	struct pnfs_osd_targetid {
188	u32 oti_type;
189	struct nfs4_string oti_scsi_device_id;
190	};
191
192	enum { PNFS_OSD_TARGETID_MAX = 1 + PNFS_OSD_OSDNAME_MAXSIZE / 4 };
193
194	/* struct netaddr4 {
195	* // see struct rpcb in RFC1833
196	* string r_netid<>; // network id
197	* string r_addr<>; // universal address
198	* };
199	*/
200	struct pnfs_osd_net_addr {
201	struct nfs4_string r_netid;
202	struct nfs4_string r_addr;
203	};
204
205	struct pnfs_osd_targetaddr {
206	u32 ota_available;
207	struct pnfs_osd_net_addr ota_netaddr;
208	};
209
210	enum {
211	NETWORK_ID_MAX = 16 / 4,
212	UNIVERSAL_ADDRESS_MAX = 64 / 4,
213	PNFS_OSD_TARGETADDR_MAX = 3 + NETWORK_ID_MAX + UNIVERSAL_ADDRESS_MAX,
214	};
215
216	struct pnfs_osd_deviceaddr {
217	struct pnfs_osd_targetid oda_targetid;
218	struct pnfs_osd_targetaddr oda_targetaddr;
219	u8 oda_lun[8];
220	struct nfs4_string oda_systemid;
221	struct pnfs_osd_object_cred oda_root_obj_cred;
222	struct nfs4_string oda_osdname;
223	};
224
225	enum {
226	ODA_OSDNAME_MAX = PNFS_OSD_OSDNAME_MAXSIZE / 4,
227	PNFS_OSD_DEVICEADDR_MAX =
228	PNFS_OSD_TARGETID_MAX + PNFS_OSD_TARGETADDR_MAX +
229	2 /oda_lun/ +
230	1 + OSD_SYSTEMID_LEN +
231	1 + ODA_OSDNAME_MAX,
232	};
233
234	/* LAYOUTCOMMIT: layoutupdate */
235
236	/* union pnfs_osd_deltaspaceused4 switch (bool dsu_valid) {
237	* case TRUE:
238	* int64_t dsu_delta;
239	* case FALSE:
240	* void;
241	* };
242	*
243	* struct pnfs_osd_layoutupdate4 {
244	* pnfs_osd_deltaspaceused4 olu_delta_space_used;
245	* bool olu_ioerr_flag;
246	* };
247	*/
248	struct pnfs_osd_layoutupdate {
249	u32 dsu_valid;
250	s64 dsu_delta;
251	u32 olu_ioerr_flag;
252	};
253
254	/* LAYOUTRETURN: I/O Rrror Report */
255
256	enum pnfs_osd_errno {
257	PNFS_OSD_ERR_EIO = 1,
258	PNFS_OSD_ERR_NOT_FOUND = 2,
259	PNFS_OSD_ERR_NO_SPACE = 3,
260	PNFS_OSD_ERR_BAD_CRED = 4,
261	PNFS_OSD_ERR_NO_ACCESS = 5,
262	PNFS_OSD_ERR_UNREACHABLE = 6,
263	PNFS_OSD_ERR_RESOURCE = 7
264	};
265
266	/* struct pnfs_osd_ioerr4 {
267	* pnfs_osd_objid4 oer_component;
268	* length4 oer_comp_offset;
269	* length4 oer_comp_length;
270	* bool oer_iswrite;
271	* pnfs_osd_errno4 oer_errno;
272	* };
273	*/
274	struct pnfs_osd_ioerr {
275	struct pnfs_osd_objid oer_component;
276	u64 oer_comp_offset;
277	u64 oer_comp_length;
278	u32 oer_iswrite;
279	u32 oer_errno;
280	};
281
282	/* OSD XDR API */
283	/* Layout helpers */
284	/* Layout decoding is done in two parts:
285	* 1. First Call pnfs_osd_xdr_decode_layout_map to read in only the header part
286	* of the layout. @iter members need not be initialized.
287	* Returned:
288	* @layout members are set. (@layout->olo_comps set to NULL).
289	*
290	* Zero on success, or negative error if passed xdr is broken.
291	*
292	* 2. 2nd Call pnfs_osd_xdr_decode_layout_comp() in a loop until it returns
293	* false, to decode the next component.
294	* Returned:
295	* true if there is more to decode or false if we are done or error.
296	*
297	* Example:
298	* struct pnfs_osd_xdr_decode_layout_iter iter;
299	* struct pnfs_osd_layout layout;
300	* struct pnfs_osd_object_cred comp;
301	* int status;
302	*
303	* status = pnfs_osd_xdr_decode_layout_map(&layout, &iter, xdr);
304	* if (unlikely(status))
305	* goto err;
306	* while(pnfs_osd_xdr_decode_layout_comp(&comp, &iter, xdr, &status)) {
307	* // All of @comp strings point to inside the xdr_buffer
308	* // or scrach buffer. Copy them out to user memory eg.
309	* copy_single_comp(dest_comp++, &comp);
310	* }
311	* if (unlikely(status))
312	* goto err;
313	*/
314
315	struct pnfs_osd_xdr_decode_layout_iter {
316	unsigned total_comps;
317	unsigned decoded_comps;
318	};
319
320	extern int pnfs_osd_xdr_decode_layout_map(struct pnfs_osd_layout *layout,
321	struct pnfs_osd_xdr_decode_layout_iter iter, struct xdr_stream xdr);
322
323	extern bool pnfs_osd_xdr_decode_layout_comp(struct pnfs_osd_object_cred *comp,
324	struct pnfs_osd_xdr_decode_layout_iter iter, struct xdr_stream xdr,
325	int *err);
326
327	/* Device Info helpers */
328
329	/* Note: All strings inside @deviceaddr point to space inside @p.
330	* @p should stay valid while @deviceaddr is in use.
331	*/
332	extern void pnfs_osd_xdr_decode_deviceaddr(
333	struct pnfs_osd_deviceaddr deviceaddr, __be32 p);
334
335	/* layoutupdate (layout_commit) xdr helpers */
336	extern int
337	pnfs_osd_xdr_encode_layoutupdate(struct xdr_stream *xdr,
338	struct pnfs_osd_layoutupdate *lou);
339
340	/* osd_ioerror encoding/decoding (layout_return) */
341	/* Client */
342	extern __be32 pnfs_osd_xdr_ioerr_reserve_space(struct xdr_stream xdr);
343	extern void pnfs_osd_xdr_encode_ioerr(__be32 p, struct pnfs_osd_ioerr ioerr);
344
345	#endif /* __PNFS_OSD_XDR_H__ */