lustre/ptlrpc/niobuf.c

   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 (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 (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 (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\n",
 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).  We must also have a request buffer which
 315          * is either the actual (swabbed) incoming request, or a saved copy
 316          * if this is a req saved in target_queue_final_reply(). */
 317         LASSERT (req->rq_reqmsg != NULL);
 318         LASSERT (req->rq_repmsg != NULL);
 319         LASSERT (rs != NULL);
 320         LASSERT (req->rq_repmsg == rs->rs_msg);
 321         LASSERT (may_be_difficult || !rs->rs_difficult);
 322         LASSERT (rs->rs_cb_id.cbid_fn == reply_out_callback);
 323         LASSERT (rs->rs_cb_id.cbid_arg == rs);
 324
 325         if (req->rq_export && req->rq_export->exp_obd &&
 326             req->rq_export->exp_obd->obd_fail) {
 327                 /* Failed obd's only send ENODEV */
 328                 req->rq_type = PTL_RPC_MSG_ERR;
 329                 req->rq_status = -ENODEV;
 330                 CDEBUG(D_HA, "sending ENODEV from failed obd %d\n",
 331                        req->rq_export->exp_obd->obd_minor);
 332         }
 333
 334         if (req->rq_type != PTL_RPC_MSG_ERR)
 335                 req->rq_type = PTL_RPC_MSG_REPLY;
 336
 337         lustre_msg_set_type(req->rq_repmsg, req->rq_type);
 338         lustre_msg_set_status(req->rq_repmsg, req->rq_status);
 339         lustre_msg_set_opc(req->rq_repmsg, lustre_msg_get_opc(req->rq_reqmsg));
 340
 341         if (req->rq_export == NULL || req->rq_export->exp_connection == NULL)
 342                 conn = ptlrpc_get_connection(req->rq_peer, req->rq_self, NULL);
 343         else
 344                 conn = ptlrpc_connection_addref(req->rq_export->exp_connection);
 345
 346         if (conn == NULL) {
 347                 CERROR("not replying on NULL connection\n"); /* bug 9635 */
 348                 return -ENOTCONN;
 349         }
 350         atomic_inc (&svc->srv_outstanding_replies);
 351         ptlrpc_rs_addref(rs);                   /* +1 ref for the network */
 352
 353         rc = ptl_send_buf (&rs->rs_md_h, req->rq_repmsg, req->rq_replen,
 354                            rs->rs_difficult ? LNET_ACK_REQ : LNET_NOACK_REQ,
 355                            &rs->rs_cb_id, conn,
 356                            svc->srv_rep_portal, req->rq_xid);
 357         if (rc != 0) {
 358                 atomic_dec (&svc->srv_outstanding_replies);
 359                 ptlrpc_rs_decref(rs);
 360         }
 361         ptlrpc_put_connection(conn);
 362         return rc;
 363 }
 364
 365 int ptlrpc_reply (struct ptlrpc_request *req)
 366 {
 367         return (ptlrpc_send_reply (req, 0));
 368 }
 369
 370 int ptlrpc_error(struct ptlrpc_request *req)
 371 {
 372         int rc;
 373         ENTRY;
 374
 375         if (!req->rq_repmsg) {
 376                 rc = lustre_pack_reply(req, 1, NULL, NULL);
 377                 if (rc)
 378                         RETURN(rc);
 379         }
 380
 381         req->rq_type = PTL_RPC_MSG_ERR;
 382
 383         rc = ptlrpc_send_reply(req, 0);
 384         RETURN(rc);
 385 }
 386
 387 int ptl_send_rpc(struct ptlrpc_request *request, int noreply)
 388 {
 389         int rc;
 390         int rc2;
 391         struct ptlrpc_connection *connection;
 392         lnet_handle_me_t  reply_me_h;
 393         lnet_md_t         reply_md;
 394         ENTRY;
 395
 396         OBD_FAIL_RETURN(OBD_FAIL_PTLRPC_DROP_RPC, 0);
 397
 398         LASSERT (request->rq_type == PTL_RPC_MSG_REQUEST);
 399
 400         /* If this is a re-transmit, we're required to have disengaged
 401          * cleanly from the previous attempt */
 402         LASSERT (!request->rq_receiving_reply);
 403
 404         if (request->rq_import->imp_obd &&
 405             request->rq_import->imp_obd->obd_fail) {
 406                 CDEBUG(D_HA, "muting rpc for failed imp obd %s\n",
 407                        request->rq_import->imp_obd->obd_name);
 408                 /* this prevents us from waiting in ptlrpc_queue_wait */
 409                 request->rq_err = 1;
 410                 RETURN(-ENODEV);
 411         }
 412
 413         connection = request->rq_import->imp_connection;
 414
 415         if (request->rq_bulk != NULL) {
 416                 rc = ptlrpc_register_bulk (request);
 417                 if (rc != 0)
 418                         RETURN(rc);
 419         }
 420
 421         lustre_msg_set_handle(request->rq_reqmsg,
 422                               &request->rq_import->imp_remote_handle);
 423         lustre_msg_set_type(request->rq_reqmsg, PTL_RPC_MSG_REQUEST);
 424         lustre_msg_set_conn_cnt(request->rq_reqmsg,
 425                                 request->rq_import->imp_conn_cnt);
 426
 427         if (!noreply) {
 428                 LASSERT (request->rq_replen != 0);
 429                 if (request->rq_repmsg == NULL)
 430                         OBD_ALLOC(request->rq_repmsg, request->rq_replen);
 431                 if (request->rq_repmsg == NULL)
 432                         GOTO(cleanup_bulk, rc = -ENOMEM);
 433
 434                 rc = LNetMEAttach(request->rq_reply_portal,/*XXX FIXME bug 249*/
 435                                   connection->c_peer, request->rq_xid, 0,
 436                                   LNET_UNLINK, LNET_INS_AFTER, &reply_me_h);
 437                 if (rc != 0) {
 438                         CERROR("LNetMEAttach failed: %d\n", rc);
 439                         LASSERT (rc == -ENOMEM);
 440                         GOTO(cleanup_repmsg, rc = -ENOMEM);
 441                 }
 442         }
 443
 444         spin_lock(&request->rq_lock);
 445         /* If the MD attach succeeds, there _will_ be a reply_in callback */
 446         request->rq_receiving_reply = !noreply;
 447         /* Clear any flags that may be present from previous sends. */
 448         request->rq_replied = 0;
 449         request->rq_err = 0;
 450         request->rq_timedout = 0;
 451         request->rq_net_err = 0;
 452         request->rq_resend = 0;
 453         request->rq_restart = 0;
 454         spin_unlock(&request->rq_lock);
 455
 456         if (!noreply) {
 457                 reply_md.start     = request->rq_repmsg;
 458                 reply_md.length    = request->rq_replen;
 459                 reply_md.threshold = 1;
 460                 reply_md.options   = PTLRPC_MD_OPTIONS | LNET_MD_OP_PUT;
 461                 reply_md.user_ptr  = &request->rq_reply_cbid;
 462                 reply_md.eq_handle = ptlrpc_eq_h;
 463
 464                 rc = LNetMDAttach(reply_me_h, reply_md, LNET_UNLINK,
 465                                  &request->rq_reply_md_h);
 466                 if (rc != 0) {
 467                         CERROR("LNetMDAttach failed: %d\n", rc);
 468                         LASSERT (rc == -ENOMEM);
 469                         spin_lock(&request->rq_lock);
 470                         /* ...but the MD attach didn't succeed... */
 471                         request->rq_receiving_reply = 0;
 472                         spin_unlock(&request->rq_lock);
 473                         GOTO(cleanup_me, rc -ENOMEM);
 474                 }
 475
 476                 CDEBUG(D_NET, "Setup reply buffer: %u bytes, xid "LPU64
 477                        ", portal %u\n",
 478                        request->rq_replen, request->rq_xid,
 479                        request->rq_reply_portal);
 480         }
 481
 482         /* add references on request and import for request_out_callback */
 483         ptlrpc_request_addref(request);
 484         atomic_inc(&request->rq_import->imp_inflight);
 485
 486         OBD_FAIL_TIMEOUT(OBD_FAIL_PTLRPC_DELAY_SEND, request->rq_timeout + 5);
 487
 488         request->rq_sent = CURRENT_SECONDS;
 489         ptlrpc_pinger_sending_on_import(request->rq_import);
 490         rc = ptl_send_buf(&request->rq_req_md_h,
 491                           request->rq_reqmsg, request->rq_reqlen,
 492                           LNET_NOACK_REQ, &request->rq_req_cbid,
 493                           connection,
 494                           request->rq_request_portal,
 495                           request->rq_xid);
 496         if (rc == 0) {
 497                 ptlrpc_lprocfs_rpc_sent(request);
 498                 RETURN(rc);
 499         }
 500
 501          /* drop request_out_callback refs, we couldn't start the send */
 502         atomic_dec(&request->rq_import->imp_inflight);
 503         ptlrpc_req_finished(request);
 504
 505         if (noreply)
 506                 RETURN(rc);
 507         else
 508                 GOTO(cleanup_me, rc);
 509  cleanup_me:
 510         /* MEUnlink is safe; the PUT didn't even get off the ground, and
 511          * nobody apart from the PUT's target has the right nid+XID to
 512          * access the reply buffer. */
 513         rc2 = LNetMEUnlink(reply_me_h);
 514         LASSERT (rc2 == 0);
 515         /* UNLINKED callback called synchronously */
 516         LASSERT (!request->rq_receiving_reply);
 517
 518  cleanup_repmsg:
 519         OBD_FREE(request->rq_repmsg, request->rq_replen);
 520         request->rq_repmsg = NULL;
 521
 522  cleanup_bulk:
 523         if (request->rq_bulk != NULL)
 524                 ptlrpc_unregister_bulk(request);
 525
 526         return rc;
 527 }
 528
 529 int ptlrpc_register_rqbd (struct ptlrpc_request_buffer_desc *rqbd)
 530 {
 531         struct ptlrpc_service   *service = rqbd->rqbd_service;
 532         static lnet_process_id_t  match_id = {LNET_NID_ANY, LNET_PID_ANY};
 533         int                      rc;
 534         lnet_md_t                 md;
 535         lnet_handle_me_t          me_h;
 536
 537         CDEBUG(D_NET, "LNetMEAttach: portal %d\n",
 538                service->srv_req_portal);
 539
 540         if (OBD_FAIL_CHECK_ONCE(OBD_FAIL_PTLRPC_RQBD))
 541                 return (-ENOMEM);
 542
 543         rc = LNetMEAttach(service->srv_req_portal,
 544                           match_id, 0, ~0, LNET_UNLINK, LNET_INS_AFTER, &me_h);
 545         if (rc != 0) {
 546                 CERROR("LNetMEAttach failed: %d\n", rc);
 547                 return (-ENOMEM);
 548         }
 549
 550         LASSERT(rqbd->rqbd_refcount == 0);
 551         rqbd->rqbd_refcount = 1;
 552
 553         md.start     = rqbd->rqbd_buffer;
 554         md.length    = service->srv_buf_size;
 555         md.max_size  = service->srv_max_req_size;
 556         md.threshold = LNET_MD_THRESH_INF;
 557         md.options   = PTLRPC_MD_OPTIONS | LNET_MD_OP_PUT | LNET_MD_MAX_SIZE;
 558         md.user_ptr  = &rqbd->rqbd_cbid;
 559         md.eq_handle = ptlrpc_eq_h;
 560
 561         rc = LNetMDAttach(me_h, md, LNET_UNLINK, &rqbd->rqbd_md_h);
 562         if (rc == 0)
 563                 return (0);
 564
 565         CERROR("LNetMDAttach failed: %d; \n", rc);
 566         LASSERT (rc == -ENOMEM);
 567         rc = LNetMEUnlink (me_h);
 568         LASSERT (rc == 0);
 569         rqbd->rqbd_refcount = 0;
 570
 571         return (-ENOMEM);
 572 }