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/lprocfs_status.h>
  40 #include "mdc_internal.h"
  41
  42 int it_disposition(struct lookup_intent *it, int flag)
  43 {
  44         return it->d.lustre.it_disposition & flag;
  45 }
  46 EXPORT_SYMBOL(it_disposition);
  47
  48 void it_set_disposition(struct lookup_intent *it, int flag)
  49 {
  50         it->d.lustre.it_disposition |= flag;
  51 }
  52 EXPORT_SYMBOL(it_set_disposition);
  53
  54 static void mdc_fid2mdc_op_data(struct mdc_op_data *data, struct ll_uctxt *ctxt,
  55                                 struct ll_fid *f1, struct ll_fid *f2,
  56                                 const char *name, int namelen, int mode)
  57 {
  58         LASSERT(data);
  59         LASSERT(ctxt);
  60         LASSERT(f1);
  61
  62         data->ctxt = *ctxt;
  63         data->fid1 = *f1;
  64         if (f2)
  65                 data->fid2 = *f2;
  66         else
  67                 memset(&data->fid2, 0, sizeof(data->fid2));
  68         data->name = name;
  69         data->namelen = namelen;
  70         data->create_mode = mode;
  71         data->mod_time = LTIME_S(CURRENT_TIME);
  72 }
  73
  74 static int it_to_lock_mode(struct lookup_intent *it)
  75 {
  76         /* CREAT needs to be tested before open (both could be set) */
  77         if (it->it_op & IT_CREAT)
  78                 return LCK_PW;
  79         else if (it->it_op & (IT_READDIR | IT_GETATTR | IT_OPEN | IT_LOOKUP |
  80                               IT_CHDIR))
  81                 return LCK_PR;
  82
  83         LBUG();
  84         RETURN(-EINVAL);
  85 }
  86
  87 int it_open_error(int phase, struct lookup_intent *it)
  88 {
  89         if (it_disposition(it, DISP_OPEN_OPEN)) {
  90                 if (phase == DISP_OPEN_OPEN)
  91                         return it->d.lustre.it_status;
  92                 else
  93                         return 0;
  94         }
  95
  96         if (it_disposition(it, DISP_OPEN_CREATE)) {
  97                 if (phase == DISP_OPEN_CREATE)
  98                         return it->d.lustre.it_status;
  99                 else
 100                         return 0;
 101         }
 102
 103         if (it_disposition(it, DISP_LOOKUP_EXECD)) {
 104                 if (phase == DISP_LOOKUP_EXECD)
 105                         return it->d.lustre.it_status;
 106                 else
 107                         return 0;
 108         }
 109
 110         if (it_disposition(it, DISP_IT_EXECD)) {
 111                 if (phase == DISP_IT_EXECD)
 112                         return it->d.lustre.it_status;
 113                 else
 114                         return 0;
 115         }
 116         CERROR("it disp: %X, status: %d\n", it->d.lustre.it_disposition,
 117                it->d.lustre.it_status);
 118         LBUG();
 119         return 0;
 120 }
 121 EXPORT_SYMBOL(it_open_error);
 122
 123 /* this must be called on a lockh that is known to have a referenced lock */
 124 int mdc_set_lock_data(struct obd_export *exp, __u64 *l, void *data)
 125 {
 126         struct ldlm_lock *lock;
 127         struct lustre_handle *lockh = (struct lustre_handle *)l;
 128         ENTRY;
 129
 130         if (!*l) {
 131                 EXIT;
 132                 return 0;
 133         }
 134
 135         lock = ldlm_handle2lock(lockh);
 136
 137         LASSERT(lock != NULL);
 138         l_lock(&lock->l_resource->lr_namespace->ns_lock);
 139 #ifdef __KERNEL__
 140         if (lock->l_ast_data && lock->l_ast_data != data) {
 141                 struct inode *new_inode = data;
 142                 struct inode *old_inode = lock->l_ast_data;
 143                 LASSERTF(old_inode->i_state & I_FREEING,
 144                          "Found existing inode %p/%lu/%u state %lu in lock: "
 145                          "setting data to %p/%lu/%u\n", old_inode,
 146                          old_inode->i_ino, old_inode->i_generation,
 147                          old_inode->i_state,
 148                          new_inode, new_inode->i_ino, new_inode->i_generation);
 149         }
 150 #endif
 151         lock->l_ast_data = data;
 152         l_unlock(&lock->l_resource->lr_namespace->ns_lock);
 153         LDLM_LOCK_PUT(lock);
 154
 155         EXIT;
 156         return 0;
 157 }
 158 EXPORT_SYMBOL(mdc_set_lock_data);
 159
 160 int mdc_change_cbdata(struct obd_export *exp, struct ll_fid *fid,
 161                       ldlm_iterator_t it, void *data)
 162 {
 163         struct ldlm_res_id res_id = { .name = {0} };
 164         ENTRY;
 165
 166         res_id.name[0] = fid->id;
 167         res_id.name[1] = fid->generation;
 168
 169         ldlm_change_cbdata(class_exp2obd(exp)->obd_namespace, &res_id, it,
 170                            data);
 171
 172         EXIT;
 173         return 0;
 174 }
 175
 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
 248                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 4,
 249                                       size, NULL);
 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                 if (!req)
 267                         RETURN(-ENOMEM);
 268
 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                         void *replayea;
 369                         /* The eadata is opaque; just check that it is
 370                          * there.  Eventually, obd_unpackmd() will check
 371                          * the contents */
 372                         eadata = lustre_swab_repbuf(req, 2, body->eadatasize,
 373                                                     NULL);
 374                         if (eadata == NULL) {
 375                                 CERROR ("Missing/short eadata\n");
 376                                 RETURN (-EPROTO);
 377                         }
 378                         if (it->it_op & IT_OPEN) {
 379                                 replayea = lustre_msg_buf(req->rq_reqmsg, 4,
 380                                                           obddev->u.cli.cl_max_mds_easize);
 381                                 LASSERT(replayea);
 382                                 memcpy(replayea, eadata, body->eadatasize);
 383                         }
 384                 }
 385         }
 386
 387         RETURN(rc);
 388 }
 389 EXPORT_SYMBOL(mdc_enqueue);
 390
 391 /*
 392  * This long block is all about fixing up the lock and request state
 393  * so that it is correct as of the moment _before_ the operation was
 394  * applied; that way, the VFS will think that everything is normal and
 395  * call Lustre's regular VFS methods.
 396  *
 397  * If we're performing a creation, that means that unless the creation
 398  * failed with EEXIST, we should fake up a negative dentry.
 399  *
 400  * For everything else, we want to lookup to succeed.
 401  *
 402  * One additional note: if CREATE or OPEN succeeded, we add an extra
 403  * reference to the request because we need to keep it around until
 404  * ll_create/ll_open gets called.
 405  *
 406  * The server will return to us, in it_disposition, an indication of
 407  * exactly what d.lustre.it_status refers to.
 408  *
 409  * If DISP_OPEN_OPEN is set, then d.lustre.it_status refers to the open() call,
 410  * otherwise if DISP_OPEN_CREATE is set, then it status is the
 411  * creation failure mode.  In either case, one of DISP_LOOKUP_NEG or
 412  * DISP_LOOKUP_POS will be set, indicating whether the child lookup
 413  * was successful.
 414  *
 415  * Else, if DISP_LOOKUP_EXECD then d.lustre.it_status is the rc of the
 416  * child lookup.
 417  */
 418 int mdc_intent_lock(struct obd_export *exp, struct ll_uctxt *uctxt,
 419                     struct ll_fid *pfid, const char *name, int len,
 420                     void *lmm, int lmmsize, struct ll_fid *cfid,
 421                     struct lookup_intent *it, int lookup_flags,
 422                     struct ptlrpc_request **reqp,
 423                     ldlm_blocking_callback cb_blocking)
 424 {
 425         struct lustre_handle lockh;
 426         struct ptlrpc_request *request;
 427         int rc = 0;
 428         struct mds_body *mds_body;
 429         struct lustre_handle old_lock;
 430         struct ldlm_lock *lock;
 431         ENTRY;
 432         LASSERT(it);
 433
 434         CDEBUG(D_DLMTRACE, "name: %*s in %ld, intent: %s\n", len, name,
 435                pfid ? (unsigned long) pfid->id : 0 , ldlm_it2str(it->it_op));
 436
 437         if (cfid && (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR ||
 438                      it->it_op == IT_CHDIR)) {
 439                 /* We could just return 1 immediately, but since we should only
 440                  * be called in revalidate_it if we already have a lock, let's
 441                  * verify that. */
 442                 struct ldlm_res_id res_id ={.name = {cfid->id,
 443                                                      cfid->generation}};
 444                 struct lustre_handle lockh;
 445                 ldlm_policy_data_t policy;
 446                 int mode = LCK_PR;
 447
 448                 /* For the GETATTR case, ll_revalidate_it issues two separate
 449                    queries - for LOOKUP and for UPDATE lock because if cannot
 450                    check them together - we might have those two bits to be
 451                    present in two separate granted locks */
 452                 policy.l_inodebits.bits =
 453                                  (it->it_op == IT_GETATTR)?MDS_INODELOCK_UPDATE:
 454                                                            MDS_INODELOCK_LOOKUP;
 455                 mode = LCK_PR;
 456                 rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 457                                      LDLM_FL_BLOCK_GRANTED, &res_id,
 458                                      LDLM_IBITS, &policy, LCK_PR, &lockh);
 459                 if (!rc) {
 460                         mode = LCK_PW;
 461                         rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 462                                              LDLM_FL_BLOCK_GRANTED, &res_id,
 463                                              LDLM_IBITS, &policy, LCK_PW,
 464                                              &lockh);
 465                 }
 466                 if (rc) {
 467                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 468                                sizeof(lockh));
 469                         it->d.lustre.it_lock_mode = mode;
 470                 }
 471                 RETURN(rc);
 472         }
 473
 474         /* lookup_it may be called only after revalidate_it has run, because
 475          * revalidate_it cannot return errors, only zero.  Returning zero causes
 476          * this call to lookup, which *can* return an error.
 477          *
 478          * We only want to execute the request associated with the intent one
 479          * time, however, so don't send the request again.  Instead, skip past
 480          * this and use the request from revalidate.  In this case, revalidate
 481          * never dropped its reference, so the refcounts are all OK */
 482         if (!it_disposition(it, DISP_ENQ_COMPLETE)) {
 483                 struct mdc_op_data op_data;
 484                 mdc_fid2mdc_op_data(&op_data, uctxt, pfid, cfid, name, len, 0);
 485
 486                 rc = mdc_enqueue(exp, LDLM_IBITS, it, it_to_lock_mode(it),
 487                                  &op_data, &lockh, lmm, lmmsize,
 488                                  ldlm_completion_ast, cb_blocking, NULL);
 489                 if (rc < 0)
 490                         RETURN(rc);
 491                 memcpy(&it->d.lustre.it_lock_handle, &lockh, sizeof(lockh));
 492         }
 493         request = *reqp = it->d.lustre.it_data;
 494         LASSERT(request != NULL);
 495
 496         if (!it_disposition(it, DISP_IT_EXECD)) {
 497                 /* The server failed before it even started executing the
 498                  * intent, i.e. because it couldn't unpack the request. */
 499                 LASSERT(it->d.lustre.it_status != 0);
 500                 RETURN(it->d.lustre.it_status);
 501         }
 502         rc = it_open_error(DISP_IT_EXECD, it);
 503         if (rc)
 504                 RETURN(rc);
 505
 506         mds_body = lustre_msg_buf(request->rq_repmsg, 1, sizeof(*mds_body));
 507         LASSERT(mds_body != NULL);           /* mdc_enqueue checked */
 508         LASSERT_REPSWABBED(request, 1); /* mdc_enqueue swabbed */
 509
 510         /* If we were revalidating a fid/name pair, mark the intent in
 511          * case we fail and get called again from lookup */
 512         if (cfid != NULL) {
 513                 it_set_disposition(it, DISP_ENQ_COMPLETE);
 514                 /* Also: did we find the same inode? */
 515                 /* we have to compare all the fields but type, because
 516                  * MDS can return mds/ino/generation triple if inode
 517                  * lives on another MDS -bzzz */
 518                 if (cfid->generation != mds_body->fid1.generation ||
 519                                 cfid->id != mds_body->fid1.id ||
 520                                 cfid->mds != mds_body->fid1.mds)
 521                         RETURN(-ESTALE);
 522         }
 523
 524         /* If we're doing an IT_OPEN which did not result in an actual
 525          * successful open, then we need to remove the bit which saves
 526          * this request for unconditional replay. */
 527         if (it->it_op & IT_OPEN) {
 528                 if (!it_disposition(it, DISP_OPEN_OPEN) ||
 529                     it->d.lustre.it_status != 0) {
 530                         unsigned long irqflags;
 531
 532                         spin_lock_irqsave(&request->rq_lock, irqflags);
 533                         request->rq_replay = 0;
 534                         spin_unlock_irqrestore(&request->rq_lock, irqflags);
 535                 }
 536         }
 537
 538         rc = it_open_error(DISP_LOOKUP_EXECD, it);
 539         if (rc)
 540                 RETURN(rc);
 541
 542         /* keep requests around for the multiple phases of the call
 543          * this shows the DISP_XX must guarantee we make it into the call
 544          */
 545         if (it_disposition(it, DISP_OPEN_CREATE) &&
 546             !it_open_error(DISP_OPEN_CREATE, it))
 547                 ptlrpc_request_addref(request);
 548         if (it_disposition(it, DISP_OPEN_OPEN) &&
 549             !it_open_error(DISP_OPEN_OPEN, it))
 550                 ptlrpc_request_addref(request);
 551
 552         if (it->it_op & IT_CREAT) {
 553                 /* XXX this belongs in ll_create_iit */
 554         } else if (it->it_op == IT_OPEN) {
 555                 LASSERT(!it_disposition(it, DISP_OPEN_CREATE));
 556         } else {
 557                 LASSERT(it->it_op & (IT_GETATTR | IT_LOOKUP | IT_CHDIR));
 558         }
 559
 560         /* If we already have a matching lock, then cancel the new
 561          * one.  We have to set the data here instead of in
 562          * mdc_enqueue, because we need to use the child's inode as
 563          * the l_ast_data to match, and that's not available until
 564          * intent_finish has performed the iget().) */
 565         lock = ldlm_handle2lock(&lockh);
 566         if (lock) {
 567                 ldlm_policy_data_t policy = lock->l_policy_data;
 568                 LDLM_DEBUG(lock, "matching against this");
 569                 LDLM_LOCK_PUT(lock);
 570                 memcpy(&old_lock, &lockh, sizeof(lockh));
 571                 if (ldlm_lock_match(NULL, LDLM_FL_BLOCK_GRANTED, NULL,
 572                                     LDLM_IBITS, &policy, LCK_NL, &old_lock)) {
 573                         ldlm_lock_decref_and_cancel(&lockh,
 574                                                     it->d.lustre.it_lock_mode);
 575                         memcpy(&lockh, &old_lock, sizeof(old_lock));
 576                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 577                                sizeof(lockh));
 578                 }
 579         }
 580         CDEBUG(D_DENTRY, "D_IT dentry %*s intent: %s status %d disp %x rc %d\n",
 581                len, name, ldlm_it2str(it->it_op), it->d.lustre.it_status,
 582                it->d.lustre.it_disposition, rc);
 583
 584         RETURN(rc);
 585 }
 586 EXPORT_SYMBOL(mdc_intent_lock);