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1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2  * vim:expandtab:shiftwidth=8:tabstop=8:
3  *
4  *  Copyright (c) 2002, 2003 Cluster File Systems, Inc.
5  *
6  *   This file is part of the Lustre file system, http://www.lustre.org
7  *   Lustre is a trademark of Cluster File Systems, Inc.
8  *
9  *   You may have signed or agreed to another license before downloading
10  *   this software.  If so, you are bound by the terms and conditions
11  *   of that agreement, and the following does not apply to you.  See the
12  *   LICENSE file included with this distribution for more information.
13  *
14  *   If you did not agree to a different license, then this copy of Lustre
15  *   is open source software; you can redistribute it and/or modify it
16  *   under the terms of version 2 of the GNU General Public License as
17  *   published by the Free Software Foundation.
18  *
19  *   In either case, Lustre is distributed in the hope that it will be
20  *   useful, but WITHOUT ANY WARRANTY; without even the implied warranty
21  *   of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  *   license text for more details.
23  *
24  */
25
26 #define DEBUG_SUBSYSTEM S_RPC
27 #ifndef __KERNEL__
28 #include <liblustre.h>
29 #endif
30 #include <obd_support.h>
31 #include <lustre_net.h>
32 #include <lustre_lib.h>
33 #include <obd.h>
34 #include "ptlrpc_internal.h"
35
36 static int ptl_send_buf (lnet_handle_md_t *mdh, void *base, int len,
37                          lnet_ack_req_t ack, struct ptlrpc_cb_id *cbid,
38                          struct ptlrpc_connection *conn, int portal, __u64 xid)
39 {
40         int              rc;
41         lnet_md_t         md;
42         ENTRY;
43
44         LASSERT (portal != 0);
45         LASSERT (conn != NULL);
46         CDEBUG (D_INFO, "conn=%p id %s\n", conn, libcfs_id2str(conn->c_peer));
47         md.start     = base;
48         md.length    = len;
49         md.threshold = (ack == LNET_ACK_REQ) ? 2 : 1;
50         md.options   = PTLRPC_MD_OPTIONS;
51         md.user_ptr  = cbid;
52         md.eq_handle = ptlrpc_eq_h;
53
54         if (unlikely(ack == LNET_ACK_REQ &&
55                      OBD_FAIL_CHECK(OBD_FAIL_PTLRPC_ACK | OBD_FAIL_ONCE))) {
56                 /* don't ask for the ack to simulate failing client */
57                 ack = LNET_NOACK_REQ;
58                 obd_fail_loc |= OBD_FAIL_ONCE | OBD_FAILED;
59         }
60
61         rc = LNetMDBind (md, LNET_UNLINK, mdh);
62         if (unlikely(rc != 0)) {
63                 CERROR ("LNetMDBind failed: %d\n", rc);
64                 LASSERT (rc == -ENOMEM);
65                 RETURN (-ENOMEM);
66         }
67
68         CDEBUG(D_NET, "Sending %d bytes to portal %d, xid "LPD64"\n",
69                len, portal, xid);
70
71         rc = LNetPut (conn->c_self, *mdh, ack,
72                       conn->c_peer, portal, xid, 0, 0);
73         if (unlikely(rc != 0)) {
74                 int rc2;
75                 /* We're going to get an UNLINK event when I unlink below,
76                  * which will complete just like any other failed send, so
77                  * I fall through and return success here! */
78                 CERROR("LNetPut(%s, %d, "LPD64") failed: %d\n",
79                        libcfs_id2str(conn->c_peer), portal, xid, rc);
80                 rc2 = LNetMDUnlink(*mdh);
81                 LASSERTF(rc2 == 0, "rc2 = %d\n", rc2);
82         }
83
84         RETURN (0);
85 }
86
87 int ptlrpc_start_bulk_transfer (struct ptlrpc_bulk_desc *desc)
88 {
89         struct ptlrpc_connection *conn = desc->bd_export->exp_connection;
90         int                       rc;
91         int                       rc2;
92         lnet_md_t                 md;
93         __u64                     xid;
94         ENTRY;
95
96         if (OBD_FAIL_CHECK_ONCE(OBD_FAIL_PTLRPC_BULK_PUT_NET))
97                 RETURN(0);
98
99         /* NB no locking required until desc is on the network */
100         LASSERT (!desc->bd_network_rw);
101         LASSERT (desc->bd_type == BULK_PUT_SOURCE ||
102                  desc->bd_type == BULK_GET_SINK);
103         desc->bd_success = 0;
104
105         md.user_ptr = &desc->bd_cbid;
106         md.eq_handle = ptlrpc_eq_h;
107         md.threshold = 2; /* SENT and ACK/REPLY */
108         md.options = PTLRPC_MD_OPTIONS;
109         ptlrpc_fill_bulk_md(&md, desc);
110
111         LASSERT (desc->bd_cbid.cbid_fn == server_bulk_callback);
112         LASSERT (desc->bd_cbid.cbid_arg == desc);
113
114         /* NB total length may be 0 for a read past EOF, so we send a 0
115          * length bulk, since the client expects a bulk event. */
116
117         rc = LNetMDBind(md, LNET_UNLINK, &desc->bd_md_h);
118         if (rc != 0) {
119                 CERROR("LNetMDBind failed: %d\n", rc);
120                 LASSERT (rc == -ENOMEM);
121                 RETURN(-ENOMEM);
122         }
123
124         /* Client's bulk and reply matchbits are the same */
125         xid = desc->bd_req->rq_xid;
126         CDEBUG(D_NET, "Transferring %u pages %u bytes via portal %d "
127                "id %s xid "LPX64"\n", desc->bd_iov_count,
128                desc->bd_nob, desc->bd_portal,
129                libcfs_id2str(conn->c_peer), xid);
130
131         /* Network is about to get at the memory */
132         desc->bd_network_rw = 1;
133
134         if (desc->bd_type == BULK_PUT_SOURCE)
135                 rc = LNetPut (conn->c_self, desc->bd_md_h, LNET_ACK_REQ,
136                               conn->c_peer, desc->bd_portal, xid, 0, 0);
137         else
138                 rc = LNetGet (conn->c_self, desc->bd_md_h,
139                               conn->c_peer, desc->bd_portal, xid, 0);
140
141         if (rc != 0) {
142                 /* Can't send, so we unlink the MD bound above.  The UNLINK
143                  * event this creates will signal completion with failure,
144                  * so we return SUCCESS here! */
145                 CERROR("Transfer(%s, %d, "LPX64") failed: %d\n",
146                        libcfs_id2str(conn->c_peer), desc->bd_portal, xid, rc);
147                 rc2 = LNetMDUnlink(desc->bd_md_h);
148                 LASSERT (rc2 == 0);
149         }
150
151         RETURN(0);
152 }
153
154 void ptlrpc_abort_bulk (struct ptlrpc_bulk_desc *desc)
155 {
156         /* Server side bulk abort. Idempotent. Not thread-safe (i.e. only
157          * serialises with completion callback) */
158         struct l_wait_info lwi;
159         int                rc;
160
161         LASSERT (!in_interrupt ());             /* might sleep */
162
163         if (!ptlrpc_bulk_active(desc))          /* completed or */
164                 return;                         /* never started */
165
166         /* Do not send any meaningful data over the wire for evicted clients */
167         if (desc->bd_export && desc->bd_export->exp_failed)
168                 ptl_rpc_wipe_bulk_pages(desc);
169
170         /* The unlink ensures the callback happens ASAP and is the last
171          * one.  If it fails, it must be because completion just happened,
172          * but we must still l_wait_event() in this case, to give liblustre
173          * a chance to run server_bulk_callback()*/
174
175         LNetMDUnlink (desc->bd_md_h);
176
177         for (;;) {
178                 /* Network access will complete in finite time but the HUGE
179                  * timeout lets us CWARN for visibility of sluggish NALs */
180                 lwi = LWI_TIMEOUT (cfs_time_seconds(300), NULL, NULL);
181                 rc = l_wait_event(desc->bd_waitq,
182                                   !ptlrpc_bulk_active(desc), &lwi);
183                 if (rc == 0)
184                         return;
185
186                 LASSERT(rc == -ETIMEDOUT);
187                 CWARN("Unexpectedly long timeout: desc %p\n", desc);
188         }
189 }
190
191 int ptlrpc_register_bulk (struct ptlrpc_request *req)
192 {
193         struct ptlrpc_bulk_desc *desc = req->rq_bulk;
194         lnet_process_id_t peer;
195         int rc;
196         int rc2;
197         lnet_handle_me_t  me_h;
198         lnet_md_t         md;
199         ENTRY;
200
201         if (OBD_FAIL_CHECK_ONCE(OBD_FAIL_PTLRPC_BULK_GET_NET))
202                 RETURN(0);
203
204         /* NB no locking required until desc is on the network */
205         LASSERT (desc->bd_nob > 0);
206         LASSERT (!desc->bd_network_rw);
207         LASSERT (desc->bd_iov_count <= PTLRPC_MAX_BRW_PAGES);
208         LASSERT (desc->bd_req != NULL);
209         LASSERT (desc->bd_type == BULK_PUT_SINK ||
210                  desc->bd_type == BULK_GET_SOURCE);
211
212         desc->bd_success = 0;
213
214         peer = desc->bd_import->imp_connection->c_peer;
215
216         md.user_ptr = &desc->bd_cbid;
217         md.eq_handle = ptlrpc_eq_h;
218         md.threshold = 1;                       /* PUT or GET */
219         md.options = PTLRPC_MD_OPTIONS |
220                      ((desc->bd_type == BULK_GET_SOURCE) ?
221                       LNET_MD_OP_GET : LNET_MD_OP_PUT);
222         ptlrpc_fill_bulk_md(&md, desc);
223
224         LASSERT (desc->bd_cbid.cbid_fn == client_bulk_callback);
225         LASSERT (desc->bd_cbid.cbid_arg == desc);
226
227         /* XXX Registering the same xid on retried bulk makes my head
228          * explode trying to understand how the original request's bulk
229          * might interfere with the retried request -eeb */
230         LASSERTF (!desc->bd_registered || req->rq_xid != desc->bd_last_xid,
231                   "registered: %d  rq_xid: "LPU64" bd_last_xid: "LPU64"\n",
232                   desc->bd_registered, req->rq_xid, desc->bd_last_xid);
233         desc->bd_registered = 1;
234         desc->bd_last_xid = req->rq_xid;
235
236         rc = LNetMEAttach(desc->bd_portal, peer,
237                          req->rq_xid, 0, LNET_UNLINK, LNET_INS_AFTER, &me_h);
238         if (rc != 0) {
239                 CERROR("LNetMEAttach failed: %d\n", rc);
240                 LASSERT (rc == -ENOMEM);
241                 RETURN (-ENOMEM);
242         }
243
244         /* About to let the network at it... */
245         desc->bd_network_rw = 1;
246         rc = LNetMDAttach(me_h, md, LNET_UNLINK, &desc->bd_md_h);
247         if (rc != 0) {
248                 CERROR("LNetMDAttach failed: %d\n", rc);
249                 LASSERT (rc == -ENOMEM);
250                 desc->bd_network_rw = 0;
251                 rc2 = LNetMEUnlink (me_h);
252                 LASSERT (rc2 == 0);
253                 RETURN (-ENOMEM);
254         }
255
256         CDEBUG(D_NET, "Setup bulk %s buffers: %u pages %u bytes, xid "LPX64", "
257                "portal %u\n",
258                desc->bd_type == BULK_GET_SOURCE ? "get-source" : "put-sink",
259                desc->bd_iov_count, desc->bd_nob,
260                req->rq_xid, desc->bd_portal);
261         RETURN(0);
262 }
263
264 void ptlrpc_unregister_bulk (struct ptlrpc_request *req)
265 {
266         /* Disconnect a bulk desc from the network. Idempotent. Not
267          * thread-safe (i.e. only interlocks with completion callback). */
268         struct ptlrpc_bulk_desc *desc = req->rq_bulk;
269         cfs_waitq_t             *wq;
270         struct l_wait_info       lwi;
271         int                      rc;
272
273         LASSERT (!in_interrupt ());     /* might sleep */
274
275         if (!ptlrpc_bulk_active(desc))  /* completed or */
276                 return;                 /* never registered */
277
278         LASSERT (desc->bd_req == req);  /* bd_req NULL until registered */
279
280         /* the unlink ensures the callback happens ASAP and is the last
281          * one.  If it fails, it must be because completion just happened,
282          * but we must still l_wait_event() in this case to give liblustre
283          * a chance to run client_bulk_callback() */
284
285         LNetMDUnlink (desc->bd_md_h);
286
287         if (req->rq_set != NULL)
288                 wq = &req->rq_set->set_waitq;
289         else
290                 wq = &req->rq_reply_waitq;
291
292         for (;;) {
293                 /* Network access will complete in finite time but the HUGE
294                  * timeout lets us CWARN for visibility of sluggish NALs */
295                 lwi = LWI_TIMEOUT (cfs_time_seconds(300), NULL, NULL);
296                 rc = l_wait_event(*wq, !ptlrpc_bulk_active(desc), &lwi);
297                 if (rc == 0)
298                         return;
299
300                 LASSERT (rc == -ETIMEDOUT);
301                 DEBUG_REQ(D_WARNING,req,"Unexpectedly long timeout: desc %p",
302                           desc);
303         }
304 }
305
306 int ptlrpc_send_reply (struct ptlrpc_request *req, int may_be_difficult)
307 {
308         struct ptlrpc_service     *svc = req->rq_rqbd->rqbd_service;
309         struct ptlrpc_reply_state *rs = req->rq_reply_state;
310         struct ptlrpc_connection  *conn;
311         int                        rc;
312
313         /* We must already have a reply buffer (only ptlrpc_error() may be
314          * called without one). The reply generated by security layer (e.g.
315          * error notify, etc.) might have NULL rq->reqmsg; Otherwise we must
316          * have a request buffer which is either the actual (swabbed) incoming
317          * request, or a saved copy if this is a req saved in
318          * target_queue_final_reply().
319          */
320         LASSERT (req->rq_reqbuf != NULL);
321         LASSERT (rs != NULL);
322         LASSERT (may_be_difficult || !rs->rs_difficult);
323         LASSERT (req->rq_repmsg != NULL);
324         LASSERT (req->rq_repmsg == rs->rs_msg);
325         LASSERT (rs->rs_cb_id.cbid_fn == reply_out_callback);
326         LASSERT (rs->rs_cb_id.cbid_arg == rs);
327
328         if (unlikely(req->rq_export && req->rq_export->exp_obd &&
329                      req->rq_export->exp_obd->obd_fail)) {
330                 /* Failed obd's only send ENODEV */
331                 req->rq_type = PTL_RPC_MSG_ERR;
332                 req->rq_status = -ENODEV;
333                 CDEBUG(D_HA, "sending ENODEV from failed obd %d\n",
334                        req->rq_export->exp_obd->obd_minor);
335         }
336
337         if (req->rq_type != PTL_RPC_MSG_ERR)
338                 req->rq_type = PTL_RPC_MSG_REPLY;
339
340         lustre_msg_set_type(req->rq_repmsg, req->rq_type);
341         lustre_msg_set_status(req->rq_repmsg, req->rq_status);
342         lustre_msg_set_opc(req->rq_repmsg,
343                 req->rq_reqmsg ? lustre_msg_get_opc(req->rq_reqmsg) : 0);
344
345         if (req->rq_export == NULL || req->rq_export->exp_connection == NULL)
346                 conn = ptlrpc_get_connection(req->rq_peer, req->rq_self, NULL);
347         else
348                 conn = ptlrpc_connection_addref(req->rq_export->exp_connection);
349
350         if (unlikely(conn == NULL)) {
351                 CERROR("not replying on NULL connection\n"); /* bug 9635 */
352                 return -ENOTCONN;
353         }
354         atomic_inc (&svc->srv_outstanding_replies);
355         ptlrpc_rs_addref(rs);                   /* +1 ref for the network */
356
357         rc = sptlrpc_svc_wrap_reply(req);
358         if (unlikely(rc))
359                 goto out;
360
361         rc = ptl_send_buf (&rs->rs_md_h, rs->rs_repbuf, rs->rs_repdata_len,
362                            rs->rs_difficult ? LNET_ACK_REQ : LNET_NOACK_REQ,
363                            &rs->rs_cb_id, conn,
364                            svc->srv_rep_portal, req->rq_xid);
365 out:
366         if (unlikely(rc != 0)) {
367                 atomic_dec (&svc->srv_outstanding_replies);
368                 ptlrpc_rs_decref(rs);
369         }
370         ptlrpc_put_connection(conn);
371         return rc;
372 }
373
374 int ptlrpc_reply (struct ptlrpc_request *req)
375 {
376         return (ptlrpc_send_reply (req, 0));
377 }
378
379 int ptlrpc_error(struct ptlrpc_request *req)
380 {
381         int rc;
382         ENTRY;
383
384         if (!req->rq_repmsg) {
385                 rc = lustre_pack_reply(req, 1, NULL, NULL);
386                 if (rc)
387                         RETURN(rc);
388         }
389
390         req->rq_type = PTL_RPC_MSG_ERR;
391
392         rc = ptlrpc_send_reply(req, 0);
393         RETURN(rc);
394 }
395
396 int ptl_send_rpc(struct ptlrpc_request *request, int noreply)
397 {
398         int rc;
399         int rc2;
400         struct ptlrpc_connection *connection;
401         lnet_handle_me_t  reply_me_h;
402         lnet_md_t         reply_md;
403         ENTRY;
404
405         OBD_FAIL_RETURN(OBD_FAIL_PTLRPC_DROP_RPC, 0);
406
407         LASSERT (request->rq_type == PTL_RPC_MSG_REQUEST);
408
409         /* If this is a re-transmit, we're required to have disengaged
410          * cleanly from the previous attempt */
411         LASSERT (!request->rq_receiving_reply);
412
413         if (request->rq_import->imp_obd &&
414             request->rq_import->imp_obd->obd_fail) {
415                 CDEBUG(D_HA, "muting rpc for failed imp obd %s\n",
416                        request->rq_import->imp_obd->obd_name);
417                 /* this prevents us from waiting in ptlrpc_queue_wait */
418                 request->rq_err = 1;
419                 RETURN(-ENODEV);
420         }
421
422         connection = request->rq_import->imp_connection;
423
424         lustre_msg_set_handle(request->rq_reqmsg,
425                               &request->rq_import->imp_remote_handle);
426         lustre_msg_set_type(request->rq_reqmsg, PTL_RPC_MSG_REQUEST);
427         lustre_msg_set_conn_cnt(request->rq_reqmsg,
428                                 request->rq_import->imp_conn_cnt);
429
430         rc = sptlrpc_cli_wrap_request(request);
431         if (rc)
432                 RETURN(rc);
433
434         /* bulk register should be done after wrap_request() */
435         if (request->rq_bulk != NULL) {
436                 rc = ptlrpc_register_bulk (request);
437                 if (rc != 0)
438                         RETURN(rc);
439         }
440
441         if (!noreply) {
442                 LASSERT (request->rq_replen != 0);
443                 if (request->rq_repbuf == NULL) {
444                         rc = sptlrpc_cli_alloc_repbuf(request,
445                                                       request->rq_replen);
446                         if (rc)
447                                 GOTO(cleanup_bulk, rc);
448                 }
449
450                 rc = LNetMEAttach(request->rq_reply_portal,/*XXX FIXME bug 249*/
451                                   connection->c_peer, request->rq_xid, 0,
452                                   LNET_UNLINK, LNET_INS_AFTER, &reply_me_h);
453                 if (rc != 0) {
454                         CERROR("LNetMEAttach failed: %d\n", rc);
455                         LASSERT (rc == -ENOMEM);
456                         GOTO(cleanup_bulk, rc = -ENOMEM);
457                 }
458         }
459
460         spin_lock(&request->rq_lock);
461         /* If the MD attach succeeds, there _will_ be a reply_in callback */
462         request->rq_receiving_reply = !noreply;
463         /* Clear any flags that may be present from previous sends. */
464         request->rq_replied = 0;
465         request->rq_err = 0;
466         request->rq_timedout = 0;
467         request->rq_net_err = 0;
468         request->rq_resend = 0;
469         request->rq_restart = 0;
470         spin_unlock(&request->rq_lock);
471
472         if (!noreply) {
473                 reply_md.start     = request->rq_repbuf;
474                 reply_md.length    = request->rq_repbuf_len;
475                 reply_md.threshold = 1;
476                 reply_md.options   = PTLRPC_MD_OPTIONS | LNET_MD_OP_PUT;
477                 reply_md.user_ptr  = &request->rq_reply_cbid;
478                 reply_md.eq_handle = ptlrpc_eq_h;
479
480                 rc = LNetMDAttach(reply_me_h, reply_md, LNET_UNLINK,
481                                  &request->rq_reply_md_h);
482                 if (rc != 0) {
483                         CERROR("LNetMDAttach failed: %d\n", rc);
484                         LASSERT (rc == -ENOMEM);
485                         spin_lock(&request->rq_lock);
486                         /* ...but the MD attach didn't succeed... */
487                         request->rq_receiving_reply = 0;
488                         spin_unlock(&request->rq_lock);
489                         GOTO(cleanup_me, rc -ENOMEM);
490                 }
491
492                 CDEBUG(D_NET, "Setup reply buffer: %u bytes, xid "LPU64
493                        ", portal %u\n",
494                        request->rq_repbuf_len, request->rq_xid,
495                        request->rq_reply_portal);
496         }
497
498         /* add references on request and import for request_out_callback */
499         ptlrpc_request_addref(request);
500         atomic_inc(&request->rq_import->imp_inflight);
501
502         OBD_FAIL_TIMEOUT(OBD_FAIL_PTLRPC_DELAY_SEND, request->rq_timeout + 5);
503
504         request->rq_sent = CURRENT_SECONDS;
505         ptlrpc_pinger_sending_on_import(request->rq_import);
506         rc = ptl_send_buf(&request->rq_req_md_h,
507                           request->rq_reqbuf, request->rq_reqdata_len,
508                           LNET_NOACK_REQ, &request->rq_req_cbid,
509                           connection,
510                           request->rq_request_portal,
511                           request->rq_xid);
512         if (rc == 0) {
513                 ptlrpc_lprocfs_rpc_sent(request);
514                 RETURN(rc);
515         }
516
517          /* drop request_out_callback refs, we couldn't start the send */
518         atomic_dec(&request->rq_import->imp_inflight);
519         ptlrpc_req_finished(request);
520
521         if (noreply)
522                 RETURN(rc);
523         else
524                 GOTO(cleanup_me, rc);
525  cleanup_me:
526         /* MEUnlink is safe; the PUT didn't even get off the ground, and
527          * nobody apart from the PUT's target has the right nid+XID to
528          * access the reply buffer. */
529         rc2 = LNetMEUnlink(reply_me_h);
530         LASSERT (rc2 == 0);
531         /* UNLINKED callback called synchronously */
532         LASSERT (!request->rq_receiving_reply);
533
534  cleanup_bulk:
535         if (request->rq_bulk != NULL)
536                 ptlrpc_unregister_bulk(request);
537
538         return rc;
539 }
540
541 int ptlrpc_register_rqbd (struct ptlrpc_request_buffer_desc *rqbd)
542 {
543         struct ptlrpc_service   *service = rqbd->rqbd_service;
544         static lnet_process_id_t  match_id = {LNET_NID_ANY, LNET_PID_ANY};
545         int                      rc;
546         lnet_md_t                 md;
547         lnet_handle_me_t          me_h;
548
549         CDEBUG(D_NET, "LNetMEAttach: portal %d\n",
550                service->srv_req_portal);
551
552         if (OBD_FAIL_CHECK_ONCE(OBD_FAIL_PTLRPC_RQBD))
553                 return (-ENOMEM);
554
555         rc = LNetMEAttach(service->srv_req_portal,
556                           match_id, 0, ~0, LNET_UNLINK, LNET_INS_AFTER, &me_h);
557         if (rc != 0) {
558                 CERROR("LNetMEAttach failed: %d\n", rc);
559                 return (-ENOMEM);
560         }
561
562         LASSERT(rqbd->rqbd_refcount == 0);
563         rqbd->rqbd_refcount = 1;
564
565         md.start     = rqbd->rqbd_buffer;
566         md.length    = service->srv_buf_size;
567         md.max_size  = service->srv_max_req_size;
568         md.threshold = LNET_MD_THRESH_INF;
569         md.options   = PTLRPC_MD_OPTIONS | LNET_MD_OP_PUT | LNET_MD_MAX_SIZE;
570         md.user_ptr  = &rqbd->rqbd_cbid;
571         md.eq_handle = ptlrpc_eq_h;
572
573         rc = LNetMDAttach(me_h, md, LNET_UNLINK, &rqbd->rqbd_md_h);
574         if (rc == 0)
575                 return (0);
576
577         CERROR("LNetMDAttach failed: %d; \n", rc);
578         LASSERT (rc == -ENOMEM);
579         rc = LNetMEUnlink (me_h);
580         LASSERT (rc == 0);
581         rqbd->rqbd_refcount = 0;
582
583         return (-ENOMEM);
584 }