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 Lustre, http://www.sf.net/projects/lustre/
   7  *
   8  *   Lustre is free software; you can redistribute it and/or
   9  *   modify it under the terms of version 2 of the GNU General Public
  10  *   License as published by the Free Software Foundation.
  11  *
  12  *   Lustre is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with Lustre; if not, write to the Free Software
  19  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #ifndef EXPORT_SYMTAB
  23 # define EXPORT_SYMTAB
  24 #endif
  25 #define DEBUG_SUBSYSTEM S_MDC
  26
  27 #ifdef __KERNEL__
  28 # include <linux/module.h>
  29 # include <linux/pagemap.h>
  30 # include <linux/miscdevice.h>
  31 # include <linux/init.h>
  32 #else
  33 # include <liblustre.h>
  34 #endif
  35
  36 #include <linux/obd_class.h>
  37 #include <linux/lustre_mds.h>
  38 #include <linux/lustre_dlm.h>
  39 //#include <linux/lustre_smfs.h>
  40 //#include <linux/lustre_snap.h>
  41 #include <linux/lprocfs_status.h>
  42 #include "mdc_internal.h"
  43
  44 int it_disposition(struct lookup_intent *it, int flag)
  45 {
  46         return it->d.lustre.it_disposition & flag;
  47 }
  48 EXPORT_SYMBOL(it_disposition);
  49
  50 void it_set_disposition(struct lookup_intent *it, int flag)
  51 {
  52         it->d.lustre.it_disposition |= flag;
  53 }
  54 EXPORT_SYMBOL(it_set_disposition);
  55
  56 static void mdc_fid2mdc_op_data(struct mdc_op_data *data, struct ll_uctxt *ctxt,
  57                                 struct ll_fid *f1, struct ll_fid *f2,
  58                                 const char *name, int namelen, int mode)
  59 {
  60         LASSERT(data);
  61         LASSERT(ctxt);
  62         LASSERT(f1);
  63
  64         data->ctxt = *ctxt;
  65         data->fid1 = *f1;
  66         if (f2)
  67                 data->fid2 = *f2;
  68         else
  69                 memset(&data->fid2, 0, sizeof(data->fid2));
  70         data->name = name;
  71         data->namelen = namelen;
  72         data->create_mode = mode;
  73         data->mod_time = LTIME_S(CURRENT_TIME);
  74 }
  75
  76 static int it_to_lock_mode(struct lookup_intent *it)
  77 {
  78         /* CREAT needs to be tested before open (both could be set) */
  79         if (it->it_op & IT_CREAT)
  80                 return LCK_PW;
  81         else if (it->it_op & (IT_READDIR | IT_GETATTR | IT_OPEN | IT_LOOKUP |
  82                               IT_CHDIR))
  83                 return LCK_PR;
  84
  85         LBUG();
  86         RETURN(-EINVAL);
  87 }
  88
  89 int it_open_error(int phase, struct lookup_intent *it)
  90 {
  91         if (it_disposition(it, DISP_OPEN_OPEN)) {
  92                 if (phase == DISP_OPEN_OPEN)
  93                         return it->d.lustre.it_status;
  94                 else
  95                         return 0;
  96         }
  97
  98         if (it_disposition(it, DISP_OPEN_CREATE)) {
  99                 if (phase == DISP_OPEN_CREATE)
 100                         return it->d.lustre.it_status;
 101                 else
 102                         return 0;
 103         }
 104
 105         if (it_disposition(it, DISP_LOOKUP_EXECD)) {
 106                 if (phase == DISP_LOOKUP_EXECD)
 107                         return it->d.lustre.it_status;
 108                 else
 109                         return 0;
 110         }
 111
 112         if (it_disposition(it, DISP_IT_EXECD)) {
 113                 if (phase == DISP_IT_EXECD)
 114                         return it->d.lustre.it_status;
 115                 else
 116                         return 0;
 117         }
 118         CERROR("it disp: %X, status: %d\n", it->d.lustre.it_disposition,
 119                it->d.lustre.it_status);
 120         LBUG();
 121         return 0;
 122 }
 123 EXPORT_SYMBOL(it_open_error);
 124
 125 /* this must be called on a lockh that is known to have a referenced lock */
 126 int mdc_set_lock_data(struct obd_export *exp, __u64 *l, void *data)
 127 {
 128         struct ldlm_lock *lock;
 129         struct lustre_handle *lockh = (struct lustre_handle *)l;
 130         ENTRY;
 131
 132         if (!*l) {
 133                 EXIT;
 134                 return 0;
 135         }
 136
 137         lock = ldlm_handle2lock(lockh);
 138
 139         LASSERT(lock != NULL);
 140         l_lock(&lock->l_resource->lr_namespace->ns_lock);
 141 #ifdef __KERNEL__
 142         if (lock->l_ast_data && lock->l_ast_data != data) {
 143                 struct inode *new_inode = data;
 144                 struct inode *old_inode = lock->l_ast_data;
 145                 LASSERTF(old_inode->i_state & I_FREEING,
 146                          "Found existing inode %p/%lu/%u state %lu in lock: "
 147                          "setting data to %p/%lu/%u\n", old_inode,
 148                          old_inode->i_ino, old_inode->i_generation,
 149                          old_inode->i_state,
 150                          new_inode, new_inode->i_ino, new_inode->i_generation);
 151         }
 152 #endif
 153         lock->l_ast_data = data;
 154         l_unlock(&lock->l_resource->lr_namespace->ns_lock);
 155         LDLM_LOCK_PUT(lock);
 156
 157         EXIT;
 158         return 0;
 159 }
 160 EXPORT_SYMBOL(mdc_set_lock_data);
 161
 162 int mdc_change_cbdata(struct obd_export *exp, struct ll_fid *fid,
 163                       ldlm_iterator_t it, void *data)
 164 {
 165         struct ldlm_res_id res_id = { .name = {0} };
 166         ENTRY;
 167
 168         res_id.name[0] = fid->id;
 169         res_id.name[1] = fid->generation;
 170
 171         ldlm_change_cbdata(class_exp2obd(exp)->obd_namespace, &res_id, it,
 172                            data);
 173
 174         EXIT;
 175         return 0;
 176 }
 177
 178 /* We always reserve enough space in the reply packet for a stripe MD, because
 179  * we don't know in advance the file type. */
 180 int mdc_enqueue(struct obd_export *exp,
 181                 int lock_type,
 182                 struct lookup_intent *it,
 183                 int lock_mode,
 184                 struct mdc_op_data *data,
 185                 struct lustre_handle *lockh,
 186                 void *lmm,
 187                 int lmmsize,
 188                 ldlm_completion_callback cb_completion,
 189                 ldlm_blocking_callback cb_blocking,
 190                 void *cb_data)
 191 {
 192         struct ptlrpc_request *req;
 193         struct obd_device *obddev = class_exp2obd(exp);
 194         struct ldlm_res_id res_id =
 195                 { .name = {data->fid1.id, data->fid1.generation} };
 196         ldlm_policy_data_t policy = { .l_inodebits = { MDS_INODELOCK_LOOKUP } };
 197         int size[6] = {sizeof(struct ldlm_request), sizeof(struct ldlm_intent)};
 198         int rc, flags = LDLM_FL_HAS_INTENT;
 199         int repsize[4] = {sizeof(struct ldlm_reply),
 200                           sizeof(struct mds_body),
 201                           obddev->u.cli.cl_max_mds_easize,
 202                           obddev->u.cli.cl_max_mds_cookiesize};
 203         struct ldlm_reply *dlm_rep;
 204         struct ldlm_intent *lit;
 205         struct ldlm_request *lockreq;
 206         void *eadata;
 207         unsigned long irqflags;
 208         int   reply_buffers = 0;
 209         ENTRY;
 210
 211 //        LDLM_DEBUG_NOLOCK("mdsintent=%s,name=%s,dir=%lu",
 212 //                          ldlm_it2str(it->it_op), it_name, it_inode->i_ino);
 213
 214         if (it->it_op & IT_OPEN) {
 215                 it->it_create_mode |= S_IFREG;
 216                 it->it_create_mode &= ~current->fs->umask;
 217
 218                 size[2] = sizeof(struct mds_rec_create);
 219                 size[3] = data->namelen + 1;
 220                 size[4] = obddev->u.cli.cl_max_mds_easize;
 221                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE,
 222                                       5, size, NULL);
 223                 if (!req)
 224                         RETURN(-ENOMEM);
 225
 226                 spin_lock_irqsave (&req->rq_lock, irqflags);
 227                 req->rq_replay = 1;
 228                 spin_unlock_irqrestore (&req->rq_lock, irqflags);
 229
 230                 /* pack the intent */
 231                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 232                 lit->opc = (__u64)it->it_op;
 233
 234                 /* pack the intended request */
 235                 mdc_open_pack(req->rq_reqmsg, 2, data, it->it_create_mode, 0,
 236                               it->it_flags, lmm, lmmsize);
 237                 /* get ready for the reply */
 238                 reply_buffers = 3;
 239                 req->rq_replen = lustre_msg_size(3, repsize);
 240         } else if (it->it_op & (IT_GETATTR | IT_LOOKUP | IT_CHDIR)) {
 241                 int valid = OBD_MD_FLNOTOBD | OBD_MD_FLEASIZE;
 242                 size[2] = sizeof(struct mds_body);
 243                 size[3] = data->namelen + 1;
 244
 245                 if (it->it_op & IT_GETATTR)
 246                         policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 247                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 4,
 248                                       size, NULL);
 249
 250                 if (!req)
 251                         RETURN(-ENOMEM);
 252
 253                 /* pack the intent */
 254                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 255                 lit->opc = (__u64)it->it_op;
 256
 257                 /* pack the intended request */
 258                 mdc_getattr_pack(req->rq_reqmsg, valid, 2, it->it_flags, data);
 259                 /* get ready for the reply */
 260                 reply_buffers = 3;
 261                 req->rq_replen = lustre_msg_size(3, repsize);
 262         } else if (it->it_op == IT_READDIR) {
 263                 policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 264                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 1,
 265                                       size, NULL);
 266
 267                 if (!req)
 268                         RETURN(-ENOMEM);
 269                 /* get ready for the reply */
 270                 reply_buffers = 1;
 271                 req->rq_replen = lustre_msg_size(1, repsize);
 272         } else if (it->it_op == IT_UNLINK) {
 273                 size[2] = sizeof(struct mds_body);
 274                 policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 275                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 3,
 276                                       size, NULL);
 277                 if (!req)
 278                         RETURN(-ENOMEM);
 279
 280                 /* pack the intended request */
 281                 mdc_getattr_pack(req->rq_reqmsg, 0,  2, 0, data);
 282
 283                 /* pack the intent */
 284                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 285                 lit->opc = (__u64)it->it_op;
 286
 287                 /* get ready for the reply */
 288                 reply_buffers = 3;
 289                 req->rq_replen = lustre_msg_size(3, repsize);
 290         } else {
 291                 LBUG();
 292                 RETURN(-EINVAL);
 293         }
 294         mdc_get_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 295         rc = ldlm_cli_enqueue(exp, req, obddev->obd_namespace, res_id,
 296                               lock_type, &policy, lock_mode, &flags,cb_blocking,
 297                               cb_completion, NULL, cb_data, NULL, 0, NULL,
 298                               lockh);
 299         mdc_put_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 300
 301         /* Similarly, if we're going to replay this request, we don't want to
 302          * actually get a lock, just perform the intent. */
 303         if (req->rq_transno || req->rq_replay) {
 304                 lockreq = lustre_msg_buf(req->rq_reqmsg, 0, sizeof (*lockreq));
 305                 lockreq->lock_flags |= LDLM_FL_INTENT_ONLY;
 306         }
 307
 308         /* This can go when we're sure that this can never happen */
 309         LASSERT(rc != -ENOENT);
 310         if (rc == ELDLM_LOCK_ABORTED) {
 311                 lock_mode = 0;
 312                 memset(lockh, 0, sizeof(*lockh));
 313                 rc = 0;
 314         } else if (rc != 0) {
 315                 CERROR("ldlm_cli_enqueue: %d\n", rc);
 316                 LASSERT (rc < 0);
 317                 ptlrpc_req_finished(req);
 318                 RETURN(rc);
 319         } else { /* rc = 0 */
 320                 struct ldlm_lock *lock = ldlm_handle2lock(lockh);
 321                 LASSERT(lock);
 322
 323                 /* If the server gave us back a different lock mode, we should
 324                  * fix up our variables. */
 325                 if (lock->l_req_mode != lock_mode) {
 326                         ldlm_lock_addref(lockh, lock->l_req_mode);
 327                         ldlm_lock_decref(lockh, lock_mode);
 328                         lock_mode = lock->l_req_mode;
 329                 }
 330
 331                 ldlm_lock_allow_match(lock);
 332                 LDLM_LOCK_PUT(lock);
 333         }
 334
 335         dlm_rep = lustre_msg_buf(req->rq_repmsg, 0, sizeof (*dlm_rep));
 336         LASSERT(dlm_rep != NULL);           /* checked by ldlm_cli_enqueue() */
 337         LASSERT_REPSWABBED(req, 0);         /* swabbed by ldlm_cli_enqueue() */
 338
 339         it->d.lustre.it_disposition = (int) dlm_rep->lock_policy_res1;
 340         it->d.lustre.it_status = (int) dlm_rep->lock_policy_res2;
 341         it->d.lustre.it_lock_mode = lock_mode;
 342         it->d.lustre.it_data = req;
 343
 344         if (it->d.lustre.it_status < 0 && req->rq_replay) {
 345                 LASSERT(req->rq_transno == 0);
 346                 /* Don't hold error requests for replay. */
 347                 spin_lock(&req->rq_lock);
 348                 req->rq_replay = 0;
 349                 spin_unlock(&req->rq_lock);
 350         }
 351
 352         DEBUG_REQ(D_RPCTRACE, req, "disposition: %x, status: %d",
 353                   it->d.lustre.it_disposition, it->d.lustre.it_status);
 354
 355         /* We know what to expect, so we do any byte flipping required here */
 356         LASSERT(reply_buffers == 4 || reply_buffers == 3 || reply_buffers == 1);
 357         if (reply_buffers >= 3) {
 358                 struct mds_body *body;
 359
 360                 body = lustre_swab_repbuf(req, 1, sizeof (*body),
 361                                            lustre_swab_mds_body);
 362                 if (body == NULL) {
 363                         CERROR ("Can't swab mds_body\n");
 364                         RETURN (-EPROTO);
 365                 }
 366
 367                 if ((body->valid & OBD_MD_FLEASIZE) != 0) {
 368                         /* The eadata is opaque; just check that it is there.
 369                          * Eventually, obd_unpackmd() will check the contents */
 370                         eadata = lustre_swab_repbuf(req, 2, body->eadatasize,
 371                                                     NULL);
 372                         if (eadata == NULL) {
 373                                 CERROR ("Missing/short eadata\n");
 374                                 RETURN (-EPROTO);
 375                         }
 376                         if (it->it_op & IT_OPEN) {
 377                                 void *replayea;
 378
 379                                 replayea = lustre_msg_buf(req->rq_reqmsg, 4,
 380                                                           body->eadatasize);
 381                                 LASSERT(replayea);
 382                                 memcpy(replayea, eadata, body->eadatasize);
 383
 384                                 LASSERT(req->rq_reqmsg->bufcount == 5);
 385                                 req->rq_reqmsg->buflens[4] = body->eadatasize;
 386                                 /* If this isn't the last buffer, we might
 387                                  * have to shift other data around. */
 388                         }
 389                 }
 390         }
 391
 392         RETURN(rc);
 393 }
 394 EXPORT_SYMBOL(mdc_enqueue);
 395
 396 /*
 397  * This long block is all about fixing up the lock and request state
 398  * so that it is correct as of the moment _before_ the operation was
 399  * applied; that way, the VFS will think that everything is normal and
 400  * call Lustre's regular VFS methods.
 401  *
 402  * If we're performing a creation, that means that unless the creation
 403  * failed with EEXIST, we should fake up a negative dentry.
 404  *
 405  * For everything else, we want to lookup to succeed.
 406  *
 407  * One additional note: if CREATE or OPEN succeeded, we add an extra
 408  * reference to the request because we need to keep it around until
 409  * ll_create/ll_open gets called.
 410  *
 411  * The server will return to us, in it_disposition, an indication of
 412  * exactly what d.lustre.it_status refers to.
 413  *
 414  * If DISP_OPEN_OPEN is set, then d.lustre.it_status refers to the open() call,
 415  * otherwise if DISP_OPEN_CREATE is set, then it status is the
 416  * creation failure mode.  In either case, one of DISP_LOOKUP_NEG or
 417  * DISP_LOOKUP_POS will be set, indicating whether the child lookup
 418  * was successful.
 419  *
 420  * Else, if DISP_LOOKUP_EXECD then d.lustre.it_status is the rc of the
 421  * child lookup.
 422  */
 423 int mdc_intent_lock(struct obd_export *exp, struct ll_uctxt *uctxt,
 424                     struct ll_fid *pfid, const char *name, int len,
 425                     void *lmm, int lmmsize, struct ll_fid *cfid,
 426                     struct lookup_intent *it, int lookup_flags,
 427                     struct ptlrpc_request **reqp,
 428                     ldlm_blocking_callback cb_blocking)
 429 {
 430         struct lustre_handle lockh;
 431         struct ptlrpc_request *request;
 432         int rc = 0;
 433         struct mds_body *mds_body;
 434         struct lustre_handle old_lock;
 435         struct ldlm_lock *lock;
 436         ENTRY;
 437         LASSERT(it);
 438
 439         CDEBUG(D_DLMTRACE, "name: %*s in %ld, intent: %s\n", len, name,
 440                pfid ? (unsigned long) pfid->id : 0 , ldlm_it2str(it->it_op));
 441
 442         if (cfid && (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR ||
 443                      it->it_op == IT_CHDIR)) {
 444                 /* We could just return 1 immediately, but since we should only
 445                  * be called in revalidate_it if we already have a lock, let's
 446                  * verify that. */
 447                 struct ldlm_res_id res_id ={.name = {cfid->id,
 448                                                      cfid->generation}};
 449                 struct lustre_handle lockh;
 450                 ldlm_policy_data_t policy;
 451                 int mode = LCK_PR;
 452
 453                 /* For the GETATTR case, ll_revalidate_it issues two separate
 454                    queries - for LOOKUP and for UPDATE lock because if cannot
 455                    check them together - we might have those two bits to be
 456                    present in two separate granted locks */
 457                 policy.l_inodebits.bits =
 458                                  (it->it_op == IT_GETATTR)?MDS_INODELOCK_UPDATE:
 459                                                            MDS_INODELOCK_LOOKUP;
 460                 mode = LCK_PR;
 461                 rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 462                                      LDLM_FL_BLOCK_GRANTED, &res_id,
 463                                      LDLM_IBITS, &policy, LCK_PR, &lockh);
 464                 if (!rc) {
 465                         mode = LCK_PW;
 466                         rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 467                                              LDLM_FL_BLOCK_GRANTED, &res_id,
 468                                              LDLM_IBITS, &policy, LCK_PW,
 469                                              &lockh);
 470                 }
 471                 if (rc) {
 472                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 473                                sizeof(lockh));
 474                         it->d.lustre.it_lock_mode = mode;
 475                 }
 476                 RETURN(rc);
 477         }
 478
 479         /* lookup_it may be called only after revalidate_it has run, because
 480          * revalidate_it cannot return errors, only zero.  Returning zero causes
 481          * this call to lookup, which *can* return an error.
 482          *
 483          * We only want to execute the request associated with the intent one
 484          * time, however, so don't send the request again.  Instead, skip past
 485          * this and use the request from revalidate.  In this case, revalidate
 486          * never dropped its reference, so the refcounts are all OK */
 487         if (!it_disposition(it, DISP_ENQ_COMPLETE)) {
 488                 struct mdc_op_data op_data;
 489                 mdc_fid2mdc_op_data(&op_data, uctxt, pfid, cfid, name, len, 0);
 490
 491                 rc = mdc_enqueue(exp, LDLM_IBITS, it, it_to_lock_mode(it),
 492                                  &op_data, &lockh, lmm, lmmsize,
 493                                  ldlm_completion_ast, cb_blocking, NULL);
 494                 if (rc < 0)
 495                         RETURN(rc);
 496                 memcpy(&it->d.lustre.it_lock_handle, &lockh, sizeof(lockh));
 497         }
 498         request = *reqp = it->d.lustre.it_data;
 499         LASSERT(request != NULL);
 500
 501         if (!it_disposition(it, DISP_IT_EXECD)) {
 502                 /* The server failed before it even started executing the
 503                  * intent, i.e. because it couldn't unpack the request. */
 504                 LASSERT(it->d.lustre.it_status != 0);
 505                 RETURN(it->d.lustre.it_status);
 506         }
 507         rc = it_open_error(DISP_IT_EXECD, it);
 508         if (rc)
 509                 RETURN(rc);
 510
 511         mds_body = lustre_msg_buf(request->rq_repmsg, 1, sizeof(*mds_body));
 512         LASSERT(mds_body != NULL);           /* mdc_enqueue checked */
 513         LASSERT_REPSWABBED(request, 1); /* mdc_enqueue swabbed */
 514
 515         /* If we were revalidating a fid/name pair, mark the intent in
 516          * case we fail and get called again from lookup */
 517         if (cfid != NULL) {
 518                 it_set_disposition(it, DISP_ENQ_COMPLETE);
 519                 /* Also: did we find the same inode? */
 520                 /* we have to compare all the fields but type, because
 521                  * MDS can return mds/ino/generation triple if inode
 522                  * lives on another MDS -bzzz */
 523                 if (cfid->generation != mds_body->fid1.generation ||
 524                                 cfid->id != mds_body->fid1.id ||
 525                                 cfid->mds != mds_body->fid1.mds)
 526                         RETURN(-ESTALE);
 527         }
 528
 529         /* If we're doing an IT_OPEN which did not result in an actual
 530          * successful open, then we need to remove the bit which saves
 531          * this request for unconditional replay. */
 532         if (it->it_op & IT_OPEN) {
 533                 if (!it_disposition(it, DISP_OPEN_OPEN) ||
 534                     it->d.lustre.it_status != 0) {
 535                         unsigned long irqflags;
 536
 537                         spin_lock_irqsave(&request->rq_lock, irqflags);
 538                         request->rq_replay = 0;
 539                         spin_unlock_irqrestore(&request->rq_lock, irqflags);
 540                 }
 541         }
 542
 543         rc = it_open_error(DISP_LOOKUP_EXECD, it);
 544         if (rc)
 545                 RETURN(rc);
 546
 547         /* keep requests around for the multiple phases of the call
 548          * this shows the DISP_XX must guarantee we make it into the call
 549          */
 550         if (it_disposition(it, DISP_OPEN_CREATE) &&
 551             !it_open_error(DISP_OPEN_CREATE, it))
 552                 ptlrpc_request_addref(request);
 553         if (it_disposition(it, DISP_OPEN_OPEN) &&
 554             !it_open_error(DISP_OPEN_OPEN, it))
 555                 ptlrpc_request_addref(request);
 556
 557         if (it->it_op & IT_CREAT) {
 558                 /* XXX this belongs in ll_create_iit */
 559         } else if (it->it_op == IT_OPEN) {
 560                 LASSERT(!it_disposition(it, DISP_OPEN_CREATE));
 561         } else {
 562                 LASSERT(it->it_op & (IT_GETATTR | IT_LOOKUP | IT_CHDIR));
 563         }
 564
 565         /* If we already have a matching lock, then cancel the new
 566          * one.  We have to set the data here instead of in
 567          * mdc_enqueue, because we need to use the child's inode as
 568          * the l_ast_data to match, and that's not available until
 569          * intent_finish has performed the iget().) */
 570         lock = ldlm_handle2lock(&lockh);
 571         if (lock) {
 572                 ldlm_policy_data_t policy = lock->l_policy_data;
 573                 LDLM_DEBUG(lock, "matching against this");
 574                 LDLM_LOCK_PUT(lock);
 575                 memcpy(&old_lock, &lockh, sizeof(lockh));
 576                 if (ldlm_lock_match(NULL, LDLM_FL_BLOCK_GRANTED, NULL,
 577                                     LDLM_IBITS, &policy, LCK_NL, &old_lock)) {
 578                         ldlm_lock_decref_and_cancel(&lockh,
 579                                                     it->d.lustre.it_lock_mode);
 580                         memcpy(&lockh, &old_lock, sizeof(old_lock));
 581                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 582                                sizeof(lockh));
 583                 }
 584         }
 585         CDEBUG(D_DENTRY, "D_IT dentry %*s intent: %s status %d disp %x rc %d\n",
 586                len, name, ldlm_it2str(it->it_op), it->d.lustre.it_status,
 587                it->d.lustre.it_disposition, rc);
 588
 589         RETURN(rc);
 590 }
 591 EXPORT_SYMBOL(mdc_intent_lock);