lustre/mdc/mdc_locks.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2001-2003 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 #ifndef EXPORT_SYMTAB
  26 # define EXPORT_SYMTAB
  27 #endif
  28 #define DEBUG_SUBSYSTEM S_MDC
  29
  30 #ifdef __KERNEL__
  31 # include <linux/module.h>
  32 # include <linux/pagemap.h>
  33 # include <linux/miscdevice.h>
  34 # include <linux/init.h>
  35 #else
  36 # include <liblustre.h>
  37 #endif
  38
  39 #include <linux/obd_class.h>
  40 #include <linux/lustre_mds.h>
  41 #include <linux/lustre_dlm.h>
  42 #include <linux/lprocfs_status.h>
  43 #include "mdc_internal.h"
  44
  45 int it_disposition(struct lookup_intent *it, int flag)
  46 {
  47         return it->d.lustre.it_disposition & flag;
  48 }
  49 EXPORT_SYMBOL(it_disposition);
  50
  51 void it_set_disposition(struct lookup_intent *it, int flag)
  52 {
  53         it->d.lustre.it_disposition |= flag;
  54 }
  55 EXPORT_SYMBOL(it_set_disposition);
  56
  57 static int it_to_lock_mode(struct lookup_intent *it)
  58 {
  59         /* CREAT needs to be tested before open (both could be set) */
  60         if (it->it_op & IT_CREAT)
  61                 return LCK_PW;
  62         else if (it->it_op & (IT_READDIR | IT_GETATTR | IT_OPEN | IT_LOOKUP))
  63                 return LCK_PR;
  64
  65         LBUG();
  66         RETURN(-EINVAL);
  67 }
  68
  69 int it_open_error(int phase, struct lookup_intent *it)
  70 {
  71         if (it_disposition(it, DISP_OPEN_OPEN)) {
  72                 if (phase >= DISP_OPEN_OPEN)
  73                         return it->d.lustre.it_status;
  74                 else
  75                         return 0;
  76         }
  77
  78         if (it_disposition(it, DISP_OPEN_CREATE)) {
  79                 if (phase >= DISP_OPEN_CREATE)
  80                         return it->d.lustre.it_status;
  81                 else
  82                         return 0;
  83         }
  84
  85         if (it_disposition(it, DISP_LOOKUP_EXECD)) {
  86                 if (phase >= DISP_LOOKUP_EXECD)
  87                         return it->d.lustre.it_status;
  88                 else
  89                         return 0;
  90         }
  91
  92         if (it_disposition(it, DISP_IT_EXECD)) {
  93                 if (phase >= DISP_IT_EXECD)
  94                         return it->d.lustre.it_status;
  95                 else
  96                         return 0;
  97         }
  98         CERROR("it disp: %X, status: %d\n", it->d.lustre.it_disposition,
  99                it->d.lustre.it_status);
 100         LBUG();
 101         return 0;
 102 }
 103 EXPORT_SYMBOL(it_open_error);
 104
 105 /* this must be called on a lockh that is known to have a referenced lock */
 106 void mdc_set_lock_data(__u64 *l, void *data)
 107 {
 108         struct ldlm_lock *lock;
 109         struct lustre_handle *lockh = (struct lustre_handle *)l;
 110         ENTRY;
 111
 112         if (!*l) {
 113                 EXIT;
 114                 return;
 115         }
 116
 117         lock = ldlm_handle2lock(lockh);
 118
 119         LASSERT(lock != NULL);
 120         l_lock(&lock->l_resource->lr_namespace->ns_lock);
 121 #ifdef __KERNEL__
 122         if (lock->l_ast_data && lock->l_ast_data != data) {
 123                 struct inode *new_inode = data;
 124                 struct inode *old_inode = lock->l_ast_data;
 125                 LASSERTF(old_inode->i_state & I_FREEING,
 126                          "Found existing inode %p/%lu/%u state %lu in lock: "
 127                          "setting data to %p/%lu/%u\n", old_inode,
 128                          old_inode->i_ino, old_inode->i_generation,
 129                          old_inode->i_state,
 130                          new_inode, new_inode->i_ino, new_inode->i_generation);
 131         }
 132 #endif
 133         lock->l_ast_data = data;
 134         l_unlock(&lock->l_resource->lr_namespace->ns_lock);
 135         LDLM_LOCK_PUT(lock);
 136
 137         EXIT;
 138 }
 139 EXPORT_SYMBOL(mdc_set_lock_data);
 140
 141 int mdc_change_cbdata(struct obd_export *exp, struct ll_fid *fid,
 142                       ldlm_iterator_t it, void *data)
 143 {
 144         struct ldlm_res_id res_id = { .name = {0} };
 145         ENTRY;
 146
 147         res_id.name[0] = fid->id;
 148         res_id.name[1] = fid->generation;
 149
 150         ldlm_change_cbdata(class_exp2obd(exp)->obd_namespace, &res_id, it,
 151                            data);
 152
 153         EXIT;
 154         return 0;
 155 }
 156
 157 static inline void mdc_clear_replay_flag(struct ptlrpc_request *req, int rc)
 158 {
 159         /* Don't hold error requests for replay. */
 160         if (req->rq_replay) {
 161                 unsigned long irqflags;
 162                 spin_lock_irqsave(&req->rq_lock, irqflags);
 163                 req->rq_replay = 0;
 164                 spin_unlock_irqrestore(&req->rq_lock, irqflags);
 165         }
 166         if (rc && req->rq_transno != 0) {
 167                 DEBUG_REQ(D_ERROR, req, "transno returned on error rc %d", rc);
 168                 LBUG();
 169         }
 170 }
 171
 172 static int round_up(int val)
 173 {
 174         int ret = 1;
 175         while (val) {
 176                 val >>= 1;
 177                 ret <<= 1;
 178         }
 179         return ret;
 180 }
 181
 182 /* Save a large LOV EA into the request buffer so that it is available
 183  * for replay.  We don't do this in the initial request because the
 184  * original request doesn't need this buffer (at most it sends just the
 185  * lov_mds_md) and it is a waste of RAM/bandwidth to send the empty
 186  * buffer and may also be difficult to allocate and save a very large
 187  * request buffer for each open. (bug 5707)
 188  *
 189  * OOM here may cause recovery failure if lmm is needed (only for the
 190  * original open if the MDS crashed just when this client also OOM'd)
 191  * but this is incredibly unlikely, and questionable whether the client
 192  * could do MDS recovery under OOM anyways... */
 193 static void mdc_realloc_openmsg(struct ptlrpc_request *req,
 194                                 struct mds_body *body, int size[5])
 195 {
 196         int new_size, old_size;
 197         struct lustre_msg *new_msg;
 198
 199         /* save old size */
 200         old_size = lustre_msg_size(5, size);
 201
 202         size[4] = body->eadatasize;
 203         new_size = lustre_msg_size(5, size);
 204         OBD_ALLOC(new_msg, new_size);
 205         if (new_msg != NULL) {
 206                 struct lustre_msg *old_msg = req->rq_reqmsg;
 207                 unsigned long irqflags;
 208
 209                 DEBUG_REQ(D_INFO, req, "replace reqmsg for larger EA %u\n",
 210                           body->eadatasize);
 211                 memcpy(new_msg, old_msg, old_size);
 212                 new_msg->buflens[4] = body->eadatasize;
 213
 214                 spin_lock_irqsave(&req->rq_lock, irqflags);
 215                 req->rq_reqmsg = new_msg;
 216                 req->rq_reqlen = new_size;
 217                 spin_unlock_irqrestore(&req->rq_lock, irqflags);
 218
 219                 OBD_FREE(old_msg, old_size);
 220         } else {
 221                 body->valid &= ~OBD_MD_FLEASIZE;
 222                 body->eadatasize = 0;
 223         }
 224 }
 225
 226 /* We always reserve enough space in the reply packet for a stripe MD, because
 227  * we don't know in advance the file type. */
 228 int mdc_enqueue(struct obd_export *exp,
 229                 int lock_type,
 230                 struct lookup_intent *it,
 231                 int lock_mode,
 232                 struct mdc_op_data *data,
 233                 struct lustre_handle *lockh,
 234                 void *lmm,
 235                 int lmmsize,
 236                 ldlm_completion_callback cb_completion,
 237                 ldlm_blocking_callback cb_blocking,
 238                 void *cb_data, int extra_lock_flags)
 239 {
 240         struct ptlrpc_request *req;
 241         struct obd_device *obddev = class_exp2obd(exp);
 242         struct ldlm_res_id res_id =
 243                 { .name = {data->fid1.id, data->fid1.generation} };
 244         int size[5] = {sizeof(struct ldlm_request), sizeof(struct ldlm_intent)};
 245         int rc, flags = extra_lock_flags | LDLM_FL_HAS_INTENT;
 246         int repsize[4] = {sizeof(struct ldlm_reply),
 247                           sizeof(struct mds_body),
 248                           obddev->u.cli.cl_max_mds_easize,
 249                           obddev->u.cli.cl_max_mds_cookiesize};
 250         struct ldlm_reply *dlm_rep;
 251         struct ldlm_intent *lit;
 252         struct ldlm_request *lockreq;
 253         void *eadata;
 254         unsigned long irqflags;
 255         int   reply_buffers = 0;
 256         ENTRY;
 257
 258 //        LDLM_DEBUG_NOLOCK("mdsintent=%s,name=%s,dir=%lu",
 259 //                          ldlm_it2str(it->it_op), it_name, it_inode->i_ino);
 260
 261         if (it->it_op & IT_OPEN) {
 262                 it->it_create_mode |= S_IFREG;
 263
 264                 size[2] = sizeof(struct mds_rec_create);
 265                 size[3] = data->namelen + 1;
 266                 /* As an optimization, we allocate an RPC request buffer for
 267                  * at least a default-sized LOV EA even if we aren't sending
 268                  * one.  We grow the whole request to the next power-of-two
 269                  * size since we get that much from a slab allocation anyways.
 270                  * This avoids an allocation below in the common case where
 271                  * we need to save a default-sized LOV EA for open replay. */
 272                 size[4] = max(lmmsize, obddev->u.cli.cl_default_mds_easize);
 273                 rc = lustre_msg_size(5, size);
 274                 if (rc & (rc - 1))
 275                         size[4] = min(size[4] + round_up(rc) - rc,
 276                                       obddev->u.cli.cl_max_mds_easize);
 277                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE,
 278                                       5, size, NULL);
 279                 if (!req)
 280                         RETURN(-ENOMEM);
 281
 282                 spin_lock_irqsave (&req->rq_lock, irqflags);
 283                 req->rq_replay = 1;
 284                 spin_unlock_irqrestore (&req->rq_lock, irqflags);
 285
 286                 /* pack the intent */
 287                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 288                 lit->opc = (__u64)it->it_op;
 289
 290                 /* pack the intended request */
 291                 mdc_open_pack(req, 2, data, it->it_create_mode, 0,
 292                               it->it_flags, lmm, lmmsize);
 293                 /* get ready for the reply */
 294                 reply_buffers = 3;
 295                 req->rq_replen = lustre_msg_size(3, repsize);
 296         } else if (it->it_op & IT_UNLINK) {
 297                 size[2] = sizeof(struct mds_rec_unlink);
 298                 size[3] = data->namelen + 1;
 299                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 4,
 300                                       size, NULL);
 301                 if (!req)
 302                         RETURN(-ENOMEM);
 303
 304                 /* pack the intent */
 305                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 306                 lit->opc = (__u64)it->it_op;
 307
 308                 /* pack the intended request */
 309                 mdc_unlink_pack(req, 2, data);
 310                 /* get ready for the reply */
 311                 reply_buffers = 4;
 312                 req->rq_replen = lustre_msg_size(4, repsize);
 313         } else if (it->it_op & (IT_GETATTR | IT_LOOKUP)) {
 314                 obd_valid valid = OBD_MD_FLGETATTR | OBD_MD_FLEASIZE;
 315                 size[2] = sizeof(struct mds_body);
 316                 size[3] = data->namelen + 1;
 317
 318                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 4,
 319                                       size, NULL);
 320                 if (!req)
 321                         RETURN(-ENOMEM);
 322
 323                 /* pack the intent */
 324                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 325                 lit->opc = (__u64)it->it_op;
 326
 327                 /* pack the intended request */
 328                 mdc_getattr_pack(req, valid, 2, it->it_flags, data);
 329                 /* get ready for the reply */
 330                 reply_buffers = 3;
 331                 req->rq_replen = lustre_msg_size(3, repsize);
 332         } else if (it->it_op == IT_READDIR) {
 333                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 1,
 334                                       size, NULL);
 335                 if (!req)
 336                         RETURN(-ENOMEM);
 337
 338                 /* get ready for the reply */
 339                 reply_buffers = 1;
 340                 req->rq_replen = lustre_msg_size(1, repsize);
 341         }  else {
 342                 LBUG();
 343                 RETURN(-EINVAL);
 344         }
 345
 346         mdc_get_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 347         rc = ldlm_cli_enqueue(exp, req, obddev->obd_namespace, res_id,
 348                               lock_type, NULL, lock_mode, &flags, cb_blocking,
 349                               cb_completion, NULL, cb_data, NULL, 0, NULL,
 350                               lockh);
 351         mdc_put_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 352
 353         /* Similarly, if we're going to replay this request, we don't want to
 354          * actually get a lock, just perform the intent. */
 355         if (req->rq_transno || req->rq_replay) {
 356                 lockreq = lustre_msg_buf(req->rq_reqmsg, 0, sizeof (*lockreq));
 357                 lockreq->lock_flags |= LDLM_FL_INTENT_ONLY;
 358         }
 359
 360         /* This can go when we're sure that this can never happen */
 361         LASSERT(rc != -ENOENT);
 362         if (rc == ELDLM_LOCK_ABORTED) {
 363                 lock_mode = 0;
 364                 memset(lockh, 0, sizeof(*lockh));
 365                 rc = 0;
 366         } else if (rc != 0) {
 367                 CERROR("ldlm_cli_enqueue: %d\n", rc);
 368                 LASSERTF(rc < 0, "rc %d\n", rc);
 369                 mdc_clear_replay_flag(req, rc);
 370                 ptlrpc_req_finished(req);
 371                 RETURN(rc);
 372         } else { /* rc = 0 */
 373                 struct ldlm_lock *lock = ldlm_handle2lock(lockh);
 374                 LASSERT(lock);
 375
 376                 /* If the server gave us back a different lock mode, we should
 377                  * fix up our variables. */
 378                 if (lock->l_req_mode != lock_mode) {
 379                         ldlm_lock_addref(lockh, lock->l_req_mode);
 380                         ldlm_lock_decref(lockh, lock_mode);
 381                         lock_mode = lock->l_req_mode;
 382                 }
 383
 384                 ldlm_lock_allow_match(lock);
 385                 LDLM_LOCK_PUT(lock);
 386         }
 387
 388         dlm_rep = lustre_msg_buf(req->rq_repmsg, 0, sizeof (*dlm_rep));
 389         LASSERT(dlm_rep != NULL);           /* checked by ldlm_cli_enqueue() */
 390         LASSERT_REPSWABBED(req, 0);         /* swabbed by ldlm_cli_enqueue() */
 391
 392         it->d.lustre.it_disposition = (int) dlm_rep->lock_policy_res1;
 393         it->d.lustre.it_status = (int) dlm_rep->lock_policy_res2;
 394         it->d.lustre.it_lock_mode = lock_mode;
 395         it->d.lustre.it_data = req;
 396
 397         if (it->d.lustre.it_status < 0 && req->rq_replay)
 398                 mdc_clear_replay_flag(req, it->d.lustre.it_status);
 399
 400         DEBUG_REQ(D_RPCTRACE, req, "op: %d disposition: %x, status: %d",
 401                   it->it_op,it->d.lustre.it_disposition,it->d.lustre.it_status);
 402
 403         /* We know what to expect, so we do any byte flipping required here */
 404         LASSERT(reply_buffers == 4 || reply_buffers == 3 || reply_buffers == 1);
 405         if (reply_buffers >= 3) {
 406                 struct mds_body *body;
 407
 408                 body = lustre_swab_repbuf(req, 1, sizeof (*body),
 409                                           lustre_swab_mds_body);
 410                 if (body == NULL) {
 411                         CERROR ("Can't swab mds_body\n");
 412                         RETURN (-EPROTO);
 413                 }
 414
 415                 if ((body->valid & OBD_MD_FLEASIZE) != 0) {
 416                         /* The eadata is opaque; just check that it is there.
 417                          * Eventually, obd_unpackmd() will check the contents */
 418                         eadata = lustre_swab_repbuf(req, 2, body->eadatasize,
 419                                                     NULL);
 420                         if (eadata == NULL) {
 421                                 CERROR ("Missing/short eadata\n");
 422                                 RETURN (-EPROTO);
 423                         }
 424                         /* We save the reply LOV EA in case we have to replay
 425                          * a create for recovery.  If we didn't allocate a
 426                          * large enough request buffer above we need to
 427                          * reallocate it here to hold the actual LOV EA. */
 428                         if (it->it_op & IT_OPEN) {
 429                                 if (req->rq_reqmsg->buflens[4] <
 430                                     body->eadatasize)
 431                                         mdc_realloc_openmsg(req, body, size);
 432
 433                                 lmm = lustre_msg_buf(req->rq_reqmsg, 4,
 434                                                      body->eadatasize);
 435                                 if (lmm)
 436                                         memcpy(lmm, eadata, body->eadatasize);
 437                         }
 438                 }
 439         }
 440
 441         RETURN(rc);
 442 }
 443 EXPORT_SYMBOL(mdc_enqueue);
 444
 445 /*
 446  * This long block is all about fixing up the lock and request state
 447  * so that it is correct as of the moment _before_ the operation was
 448  * applied; that way, the VFS will think that everything is normal and
 449  * call Lustre's regular VFS methods.
 450  *
 451  * If we're performing a creation, that means that unless the creation
 452  * failed with EEXIST, we should fake up a negative dentry.
 453  *
 454  * For everything else, we want to lookup to succeed.
 455  *
 456  * One additional note: if CREATE or OPEN succeeded, we add an extra
 457  * reference to the request because we need to keep it around until
 458  * ll_create/ll_open gets called.
 459  *
 460  * The server will return to us, in it_disposition, an indication of
 461  * exactly what d.lustre.it_status refers to.
 462  *
 463  * If DISP_OPEN_OPEN is set, then d.lustre.it_status refers to the open() call,
 464  * otherwise if DISP_OPEN_CREATE is set, then it status is the
 465  * creation failure mode.  In either case, one of DISP_LOOKUP_NEG or
 466  * DISP_LOOKUP_POS will be set, indicating whether the child lookup
 467  * was successful.
 468  *
 469  * Else, if DISP_LOOKUP_EXECD then d.lustre.it_status is the rc of the
 470  * child lookup.
 471  */
 472 int mdc_intent_lock(struct obd_export *exp, struct mdc_op_data *op_data,
 473                     void *lmm, int lmmsize, struct lookup_intent *it,
 474                     int lookup_flags, struct ptlrpc_request **reqp,
 475                     ldlm_blocking_callback cb_blocking, int extra_lock_flags)
 476 {
 477         struct lustre_handle lockh;
 478         struct ptlrpc_request *request;
 479         int rc = 0;
 480         struct mds_body *mds_body;
 481         struct lustre_handle old_lock;
 482         struct ldlm_lock *lock;
 483         ENTRY;
 484         LASSERT(it);
 485
 486         CDEBUG(D_DLMTRACE,"name: %.*s in inode "LPU64", intent: %s flags %#o\n",
 487                op_data->namelen, op_data->name, op_data->fid1.id,
 488                ldlm_it2str(it->it_op), it->it_flags);
 489
 490         if (op_data->fid2.id &&
 491             (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR)) {
 492                 /* We could just return 1 immediately, but since we should only
 493                  * be called in revalidate_it if we already have a lock, let's
 494                  * verify that. */
 495                 struct ldlm_res_id res_id = {.name ={op_data->fid2.id,
 496                                                      op_data->fid2.generation}};
 497                 struct lustre_handle lockh;
 498                 int mode = LCK_PR;
 499
 500                 rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 501                                      LDLM_FL_BLOCK_GRANTED, &res_id,
 502                                      LDLM_PLAIN, NULL, LCK_PR, &lockh);
 503                 if (!rc) {
 504                         mode = LCK_PW;
 505                         rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 506                                              LDLM_FL_BLOCK_GRANTED, &res_id,
 507                                              LDLM_PLAIN, NULL, LCK_PW, &lockh);
 508                 }
 509                 if (rc) {
 510                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 511                                sizeof(lockh));
 512                         it->d.lustre.it_lock_mode = mode;
 513                 }
 514                 RETURN(rc);
 515         }
 516
 517         /* lookup_it may be called only after revalidate_it has run, because
 518          * revalidate_it cannot return errors, only zero.  Returning zero causes
 519          * this call to lookup, which *can* return an error.
 520          *
 521          * We only want to execute the request associated with the intent one
 522          * time, however, so don't send the request again.  Instead, skip past
 523          * this and use the request from revalidate.  In this case, revalidate
 524          * never dropped its reference, so the refcounts are all OK */
 525         if (!it_disposition(it, DISP_ENQ_COMPLETE)) {
 526
 527                 rc = mdc_enqueue(exp, LDLM_PLAIN, it, it_to_lock_mode(it),
 528                                  op_data, &lockh, lmm, lmmsize,
 529                                  ldlm_completion_ast, cb_blocking, NULL,
 530                                  extra_lock_flags);
 531                 if (rc < 0)
 532                         RETURN(rc);
 533                 memcpy(&it->d.lustre.it_lock_handle, &lockh, sizeof(lockh));
 534         }
 535         request = *reqp = it->d.lustre.it_data;
 536         LASSERT(request != NULL);
 537         LASSERT(request != LP_POISON);
 538
 539         /* If we're doing an IT_OPEN which did not result in an actual
 540          * successful open, then we need to remove the bit which saves
 541          * this request for unconditional replay.
 542          *
 543          * It's important that we do this first!  Otherwise we might exit the
 544          * function without doing so, and try to replay a failed create
 545          * (bug 3440) */
 546         if (it->it_op & IT_OPEN && request->rq_replay &&
 547             (!it_disposition(it, DISP_OPEN_OPEN) ||it->d.lustre.it_status != 0))
 548                 mdc_clear_replay_flag(request, it->d.lustre.it_status);
 549
 550         if (!it_disposition(it, DISP_IT_EXECD)) {
 551                 /* The server failed before it even started executing the
 552                  * intent, i.e. because it couldn't unpack the request. */
 553                 LASSERT(it->d.lustre.it_status != 0);
 554                 RETURN(it->d.lustre.it_status);
 555         }
 556         rc = it_open_error(DISP_IT_EXECD, it);
 557         if (rc)
 558                 RETURN(rc);
 559
 560         mds_body = lustre_msg_buf(request->rq_repmsg, 1, sizeof(*mds_body));
 561         LASSERT(mds_body != NULL);           /* mdc_enqueue checked */
 562         LASSERT_REPSWABBED(request, 1); /* mdc_enqueue swabbed */
 563
 564         /* If we were revalidating a fid/name pair, mark the intent in
 565          * case we fail and get called again from lookup */
 566         if (op_data->fid2.id) {
 567                 it_set_disposition(it, DISP_ENQ_COMPLETE);
 568                 /* Also: did we find the same inode? */
 569                 if (memcmp(&op_data->fid2, &mds_body->fid1, sizeof(op_data->fid2)))
 570                         RETURN(-ESTALE);
 571         }
 572
 573         rc = it_open_error(DISP_LOOKUP_EXECD, it);
 574         if (rc)
 575                 RETURN(rc);
 576
 577         /* keep requests around for the multiple phases of the call
 578          * this shows the DISP_XX must guarantee we make it into the call
 579          */
 580         if (it_disposition(it, DISP_OPEN_CREATE) &&
 581             !it_open_error(DISP_OPEN_CREATE, it))
 582                 ptlrpc_request_addref(request); /* balanced in ll_create_node */
 583         if (it_disposition(it, DISP_OPEN_OPEN) &&
 584             !it_open_error(DISP_OPEN_OPEN, it))
 585                 ptlrpc_request_addref(request); /* balanced in ll_file_open */
 586
 587         if (it->it_op & IT_CREAT) {
 588                 /* XXX this belongs in ll_create_it */
 589         } else if (it->it_op == IT_OPEN) {
 590                 LASSERT(!it_disposition(it, DISP_OPEN_CREATE));
 591         } else {
 592                 LASSERT(it->it_op & (IT_GETATTR | IT_LOOKUP));
 593         }
 594
 595         /* If we already have a matching lock, then cancel the new
 596          * one.  We have to set the data here instead of in
 597          * mdc_enqueue, because we need to use the child's inode as
 598          * the l_ast_data to match, and that's not available until
 599          * intent_finish has performed the iget().) */
 600         lock = ldlm_handle2lock(&lockh);
 601         if (lock) {
 602                 LDLM_DEBUG(lock, "matching against this");
 603                 LDLM_LOCK_PUT(lock);
 604                 memcpy(&old_lock, &lockh, sizeof(lockh));
 605                 if (ldlm_lock_match(NULL, LDLM_FL_BLOCK_GRANTED, NULL,
 606                                     LDLM_PLAIN, NULL, LCK_NL, &old_lock)) {
 607                         ldlm_lock_decref_and_cancel(&lockh,
 608                                                     it->d.lustre.it_lock_mode);
 609                         memcpy(&lockh, &old_lock, sizeof(old_lock));
 610                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 611                                sizeof(lockh));
 612                 }
 613         }
 614         CDEBUG(D_DENTRY,"D_IT dentry %.*s intent: %s status %d disp %x rc %d\n",
 615                op_data->namelen, op_data->name, ldlm_it2str(it->it_op),
 616                it->d.lustre.it_status, it->d.lustre.it_disposition, rc);
 617
 618         RETURN(rc);
 619 }
 620 EXPORT_SYMBOL(mdc_intent_lock);