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,
  57                                 struct ll_fid *f1, struct ll_fid *f2,
  58                                 const char *name, int namelen, int mode)
  59 {
  60         LASSERT(data);
  61         LASSERT(f1);
  62
  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 /* We always reserve enough space in the reply packet for a stripe MD, because
 177  * we don't know in advance the file type. */
 178 int mdc_enqueue(struct obd_export *exp,
 179                 int lock_type,
 180                 struct lookup_intent *it,
 181                 int lock_mode,
 182                 struct mdc_op_data *data,
 183                 struct lustre_handle *lockh,
 184                 void *lmm,
 185                 int lmmsize,
 186                 ldlm_completion_callback cb_completion,
 187                 ldlm_blocking_callback cb_blocking,
 188                 void *cb_data)
 189 {
 190         struct ptlrpc_request *req;
 191         struct obd_device *obddev = class_exp2obd(exp);
 192         struct ldlm_res_id res_id =
 193                 { .name = {data->fid1.id, data->fid1.generation} };
 194         ldlm_policy_data_t policy = { .l_inodebits = { MDS_INODELOCK_LOOKUP } };
 195         struct ldlm_intent *lit;
 196         struct ldlm_request *lockreq;
 197         struct ldlm_reply *dlm_rep;
 198         int reqsize[6] = {[MDS_REQ_SECDESC_OFF] = 0,
 199                           [MDS_REQ_INTENT_LOCKREQ_OFF] = sizeof(*lockreq),
 200                           [MDS_REQ_INTENT_IT_OFF] = sizeof(*lit)};
 201         int repsize[4] = {sizeof(struct ldlm_reply),
 202                           sizeof(struct mds_body),
 203                           obddev->u.cli.cl_max_mds_easize,
 204                           obddev->u.cli.cl_max_mds_cookiesize};
 205         int req_buffers = 3, reply_buffers = 0;
 206         int rc, flags = LDLM_FL_HAS_INTENT;
 207         void *eadata;
 208         unsigned long irqflags;
 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         reqsize[0] = mdc_get_secdesc_size();
 215
 216         if (it->it_op & IT_OPEN) {
 217                 it->it_create_mode |= S_IFREG;
 218                 it->it_create_mode &= ~current->fs->umask;
 219
 220                 reqsize[req_buffers++] = sizeof(struct mds_rec_create);
 221                 reqsize[req_buffers++] = data->namelen + 1;
 222                 reqsize[req_buffers++] = obddev->u.cli.cl_max_mds_easize;
 223                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LUSTRE_DLM_VERSION,
 224                                       LDLM_ENQUEUE, req_buffers, reqsize, NULL);
 225                 if (!req)
 226                         RETURN(-ENOMEM);
 227
 228                 spin_lock_irqsave (&req->rq_lock, irqflags);
 229                 req->rq_replay = 1;
 230                 spin_unlock_irqrestore (&req->rq_lock, irqflags);
 231
 232                 /* pack the intent */
 233                 lit = lustre_msg_buf(req->rq_reqmsg, MDS_REQ_INTENT_IT_OFF,
 234                                      sizeof (*lit));
 235                 lit->opc = (__u64)it->it_op;
 236
 237                 /* pack the intended request */
 238                 mdc_open_pack(req->rq_reqmsg, MDS_REQ_INTENT_REC_OFF, data,
 239                               it->it_create_mode, 0, it->it_flags,
 240                               lmm, lmmsize);
 241                 /* get ready for the reply */
 242                 reply_buffers = 3;
 243                 req->rq_replen = lustre_msg_size(3, repsize);
 244         } else if (it->it_op & (IT_GETATTR | IT_LOOKUP | IT_CHDIR)) {
 245                 int valid = OBD_MD_FLNOTOBD | OBD_MD_FLEASIZE;
 246
 247                 reqsize[req_buffers++] = sizeof(struct mds_body);
 248                 reqsize[req_buffers++] = data->namelen + 1;
 249
 250                 if (it->it_op & IT_GETATTR)
 251                         policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 252                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LUSTRE_DLM_VERSION,
 253                                       LDLM_ENQUEUE, req_buffers, reqsize, NULL);
 254
 255                 if (!req)
 256                         RETURN(-ENOMEM);
 257
 258                 /* pack the intent */
 259                 lit = lustre_msg_buf(req->rq_reqmsg, MDS_REQ_INTENT_IT_OFF,
 260                                      sizeof (*lit));
 261                 lit->opc = (__u64)it->it_op;
 262
 263                 /* pack the intended request */
 264                 mdc_getattr_pack(req->rq_reqmsg, MDS_REQ_INTENT_REC_OFF,
 265                                  valid, it->it_flags, data);
 266                 /* get ready for the reply */
 267                 reply_buffers = 3;
 268                 req->rq_replen = lustre_msg_size(3, repsize);
 269         } else if (it->it_op == IT_READDIR) {
 270                 policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 271                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LUSTRE_DLM_VERSION,
 272                                       LDLM_ENQUEUE, 2, reqsize, NULL);
 273
 274                 if (!req)
 275                         RETURN(-ENOMEM);
 276                 /* get ready for the reply */
 277                 reply_buffers = 1;
 278                 req->rq_replen = lustre_msg_size(1, repsize);
 279         } else if (it->it_op == IT_UNLINK) {
 280                 reqsize[req_buffers++] = sizeof(struct mds_body);
 281                 policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 282                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LUSTRE_DLM_VERSION,
 283                                       LDLM_ENQUEUE, req_buffers, reqsize, NULL);
 284                 if (!req)
 285                         RETURN(-ENOMEM);
 286
 287                 /* pack the intended request */
 288                 mdc_getattr_pack(req->rq_reqmsg, MDS_REQ_INTENT_REC_OFF,
 289                                  0, 0, data);
 290
 291                 /* pack the intent */
 292                 lit = lustre_msg_buf(req->rq_reqmsg, MDS_REQ_INTENT_IT_OFF,
 293                                      sizeof (*lit));
 294                 lit->opc = (__u64)it->it_op;
 295
 296                 /* get ready for the reply */
 297                 reply_buffers = 3;
 298                 req->rq_replen = lustre_msg_size(3, repsize);
 299         } else {
 300                 LBUG();
 301                 RETURN(-EINVAL);
 302         }
 303
 304         mdc_pack_secdesc(req, reqsize[0]);
 305
 306         mdc_get_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 307         rc = ldlm_cli_enqueue(exp, req, obddev->obd_namespace, res_id,
 308                               lock_type, &policy, lock_mode, &flags,cb_blocking,
 309                               cb_completion, NULL, cb_data, NULL, 0, NULL,
 310                               lockh);
 311         mdc_put_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 312
 313         /* Similarly, if we're going to replay this request, we don't want to
 314          * actually get a lock, just perform the intent. */
 315         if (req->rq_transno || req->rq_replay) {
 316                 lockreq = lustre_msg_buf(req->rq_reqmsg,
 317                                          MDS_REQ_INTENT_LOCKREQ_OFF,
 318                                          sizeof (*lockreq));
 319                 lockreq->lock_flags |= LDLM_FL_INTENT_ONLY;
 320         }
 321
 322         /* This can go when we're sure that this can never happen */
 323         LASSERT(rc != -ENOENT);
 324         if (rc == ELDLM_LOCK_ABORTED) {
 325                 lock_mode = 0;
 326                 memset(lockh, 0, sizeof(*lockh));
 327                 rc = 0;
 328         } else if (rc != 0) {
 329                 CERROR("ldlm_cli_enqueue: %d\n", rc);
 330                 LASSERT (rc < 0);
 331                 ptlrpc_req_finished(req);
 332                 RETURN(rc);
 333         } else { /* rc = 0 */
 334                 struct ldlm_lock *lock = ldlm_handle2lock(lockh);
 335                 LASSERT(lock);
 336
 337                 /* If the server gave us back a different lock mode, we should
 338                  * fix up our variables. */
 339                 if (lock->l_req_mode != lock_mode) {
 340                         ldlm_lock_addref(lockh, lock->l_req_mode);
 341                         ldlm_lock_decref(lockh, lock_mode);
 342                         lock_mode = lock->l_req_mode;
 343                 }
 344
 345                 ldlm_lock_allow_match(lock);
 346                 LDLM_LOCK_PUT(lock);
 347         }
 348
 349         dlm_rep = lustre_msg_buf(req->rq_repmsg, 0, sizeof (*dlm_rep));
 350         LASSERT(dlm_rep != NULL);           /* checked by ldlm_cli_enqueue() */
 351         LASSERT_REPSWABBED(req, 0);         /* swabbed by ldlm_cli_enqueue() */
 352
 353         it->d.lustre.it_disposition = (int) dlm_rep->lock_policy_res1;
 354         it->d.lustre.it_status = (int) dlm_rep->lock_policy_res2;
 355         it->d.lustre.it_lock_mode = lock_mode;
 356         it->d.lustre.it_data = req;
 357
 358         if (it->d.lustre.it_status < 0 && req->rq_replay) {
 359                 LASSERT(req->rq_transno == 0);
 360                 /* Don't hold error requests for replay. */
 361                 spin_lock(&req->rq_lock);
 362                 req->rq_replay = 0;
 363                 spin_unlock(&req->rq_lock);
 364         }
 365
 366         DEBUG_REQ(D_RPCTRACE, req, "disposition: %x, status: %d",
 367                   it->d.lustre.it_disposition, it->d.lustre.it_status);
 368
 369         /* We know what to expect, so we do any byte flipping required here */
 370         LASSERT(reply_buffers == 4 || reply_buffers == 3 || reply_buffers == 1);
 371         if (reply_buffers >= 3) {
 372                 struct mds_body *body;
 373
 374                 body = lustre_swab_repbuf(req, 1, sizeof (*body),
 375                                            lustre_swab_mds_body);
 376                 if (body == NULL) {
 377                         CERROR ("Can't swab mds_body\n");
 378                         RETURN (-EPROTO);
 379                 }
 380
 381                 if ((body->valid & OBD_MD_FLEASIZE) != 0) {
 382                         /* The eadata is opaque; just check that it is there.
 383                          * Eventually, obd_unpackmd() will check the contents */
 384                         eadata = lustre_swab_repbuf(req, 2, body->eadatasize,
 385                                                     NULL);
 386                         if (eadata == NULL) {
 387                                 CERROR ("Missing/short eadata\n");
 388                                 RETURN (-EPROTO);
 389                         }
 390                         if (it->it_op & IT_OPEN) {
 391                                 void *replayea;
 392
 393                                 replayea = lustre_msg_buf(req->rq_reqmsg,
 394                                                           MDS_REQ_INTENT_REC_OFF + 2,
 395                                                           body->eadatasize);
 396                                 LASSERT(replayea);
 397                                 memcpy(replayea, eadata, body->eadatasize);
 398
 399                                 LASSERT(req->rq_reqmsg->bufcount == 6);
 400                                 req->rq_reqmsg->buflens[5] = body->eadatasize;
 401                                 /* If this isn't the last buffer, we might
 402                                  * have to shift other data around. */
 403                         }
 404                 }
 405         }
 406
 407         RETURN(rc);
 408 }
 409 EXPORT_SYMBOL(mdc_enqueue);
 410
 411 /*
 412  * This long block is all about fixing up the lock and request state
 413  * so that it is correct as of the moment _before_ the operation was
 414  * applied; that way, the VFS will think that everything is normal and
 415  * call Lustre's regular VFS methods.
 416  *
 417  * If we're performing a creation, that means that unless the creation
 418  * failed with EEXIST, we should fake up a negative dentry.
 419  *
 420  * For everything else, we want to lookup to succeed.
 421  *
 422  * One additional note: if CREATE or OPEN succeeded, we add an extra
 423  * reference to the request because we need to keep it around until
 424  * ll_create/ll_open gets called.
 425  *
 426  * The server will return to us, in it_disposition, an indication of
 427  * exactly what d.lustre.it_status refers to.
 428  *
 429  * If DISP_OPEN_OPEN is set, then d.lustre.it_status refers to the open() call,
 430  * otherwise if DISP_OPEN_CREATE is set, then it status is the
 431  * creation failure mode.  In either case, one of DISP_LOOKUP_NEG or
 432  * DISP_LOOKUP_POS will be set, indicating whether the child lookup
 433  * was successful.
 434  *
 435  * Else, if DISP_LOOKUP_EXECD then d.lustre.it_status is the rc of the
 436  * child lookup.
 437  */
 438 int mdc_intent_lock(struct obd_export *exp,
 439                     struct ll_fid *pfid, const char *name, int len,
 440                     void *lmm, int lmmsize, struct ll_fid *cfid,
 441                     struct lookup_intent *it, int lookup_flags,
 442                     struct ptlrpc_request **reqp,
 443                     ldlm_blocking_callback cb_blocking)
 444 {
 445         struct lustre_handle lockh;
 446         struct ptlrpc_request *request;
 447         int rc = 0;
 448         struct mds_body *mds_body;
 449         struct lustre_handle old_lock;
 450         struct ldlm_lock *lock;
 451         ENTRY;
 452         LASSERT(it);
 453
 454         CDEBUG(D_DLMTRACE, "name: %*s in inode "LPU64", intent: %s flags %#o\n",
 455                len, name, pfid->id, ldlm_it2str(it->it_op), it->it_flags);
 456
 457         if (cfid && (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR ||
 458                      it->it_op == IT_CHDIR)) {
 459                 /* We could just return 1 immediately, but since we should only
 460                  * be called in revalidate_it if we already have a lock, let's
 461                  * verify that. */
 462                 struct ldlm_res_id res_id ={.name = {cfid->id,
 463                                                      cfid->generation}};
 464                 struct lustre_handle lockh;
 465                 ldlm_policy_data_t policy;
 466                 int mode = LCK_PR;
 467
 468                 /* For the GETATTR case, ll_revalidate_it issues two separate
 469                    queries - for LOOKUP and for UPDATE lock because if cannot
 470                    check them together - we might have those two bits to be
 471                    present in two separate granted locks */
 472                 policy.l_inodebits.bits =
 473                                  (it->it_op == IT_GETATTR)?MDS_INODELOCK_UPDATE:
 474                                                            MDS_INODELOCK_LOOKUP;
 475                 mode = LCK_PR;
 476                 rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 477                                      LDLM_FL_BLOCK_GRANTED, &res_id,
 478                                      LDLM_IBITS, &policy, LCK_PR, &lockh);
 479                 if (!rc) {
 480                         mode = LCK_PW;
 481                         rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 482                                              LDLM_FL_BLOCK_GRANTED, &res_id,
 483                                              LDLM_IBITS, &policy, LCK_PW,
 484                                              &lockh);
 485                 }
 486                 if (rc) {
 487                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 488                                sizeof(lockh));
 489                         it->d.lustre.it_lock_mode = mode;
 490                 }
 491
 492                 /* Only return failure if it was not GETATTR by cfid
 493                    (from inode_revalidate) */
 494                 if (rc || name)
 495                         RETURN(rc);
 496         }
 497
 498         /* lookup_it may be called only after revalidate_it has run, because
 499          * revalidate_it cannot return errors, only zero.  Returning zero causes
 500          * this call to lookup, which *can* return an error.
 501          *
 502          * We only want to execute the request associated with the intent one
 503          * time, however, so don't send the request again.  Instead, skip past
 504          * this and use the request from revalidate.  In this case, revalidate
 505          * never dropped its reference, so the refcounts are all OK */
 506         if (!it_disposition(it, DISP_ENQ_COMPLETE)) {
 507                 struct mdc_op_data op_data;
 508                 mdc_fid2mdc_op_data(&op_data, pfid, cfid, name, len, 0);
 509
 510                 rc = mdc_enqueue(exp, LDLM_IBITS, it, it_to_lock_mode(it),
 511                                  &op_data, &lockh, lmm, lmmsize,
 512                                  ldlm_completion_ast, cb_blocking, NULL);
 513                 if (rc < 0)
 514                         RETURN(rc);
 515                 memcpy(&it->d.lustre.it_lock_handle, &lockh, sizeof(lockh));
 516         }
 517         request = *reqp = it->d.lustre.it_data;
 518         LASSERT(request != NULL);
 519
 520         /* If we're doing an IT_OPEN which did not result in an actual
 521          * successful open, then we need to remove the bit which saves
 522          * this request for unconditional replay.
 523          *
 524          * It's important that we do this first!  Otherwise we might exit the
 525          * function without doing so, and try to replay a failed create
 526          * (bug 3440) */
 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         if (!it_disposition(it, DISP_IT_EXECD)) {
 538                 /* The server failed before it even started executing the
 539                  * intent, i.e. because it couldn't unpack the request. */
 540                 LASSERT(it->d.lustre.it_status != 0);
 541                 RETURN(it->d.lustre.it_status);
 542         }
 543         rc = it_open_error(DISP_IT_EXECD, it);
 544         if (rc)
 545                 RETURN(rc);
 546
 547         mds_body = lustre_msg_buf(request->rq_repmsg, 1, sizeof(*mds_body));
 548         LASSERT(mds_body != NULL);           /* mdc_enqueue checked */
 549         LASSERT_REPSWABBED(request, 1); /* mdc_enqueue swabbed */
 550
 551         /* If we were revalidating a fid/name pair, mark the intent in
 552          * case we fail and get called again from lookup */
 553         if (cfid != NULL) {
 554                 it_set_disposition(it, DISP_ENQ_COMPLETE);
 555                 /* Also: did we find the same inode? */
 556                 /* we have to compare all the fields but type, because
 557                  * MDS can return mds/ino/generation triple if inode
 558                  * lives on another MDS -bzzz */
 559                 if (cfid->generation != mds_body->fid1.generation ||
 560                                 cfid->id != mds_body->fid1.id ||
 561                                 cfid->mds != mds_body->fid1.mds)
 562                         RETURN(-ESTALE);
 563         }
 564
 565         rc = it_open_error(DISP_LOOKUP_EXECD, it);
 566         if (rc)
 567                 RETURN(rc);
 568
 569         /* keep requests around for the multiple phases of the call
 570          * this shows the DISP_XX must guarantee we make it into the call
 571          */
 572         if (it_disposition(it, DISP_OPEN_CREATE) &&
 573             !it_open_error(DISP_OPEN_CREATE, it))
 574                 ptlrpc_request_addref(request); /* balanced in ll_create_node */
 575         if (it_disposition(it, DISP_OPEN_OPEN) &&
 576             !it_open_error(DISP_OPEN_OPEN, it))
 577                 ptlrpc_request_addref(request); /* balanced in ll_file_open */
 578
 579         if (it->it_op & IT_CREAT) {
 580                 /* XXX this belongs in ll_create_it */
 581         } else if (it->it_op == IT_OPEN) {
 582                 LASSERT(!it_disposition(it, DISP_OPEN_CREATE));
 583         } else {
 584                 LASSERT(it->it_op & (IT_GETATTR | IT_LOOKUP | IT_CHDIR));
 585         }
 586
 587         /* If we already have a matching lock, then cancel the new
 588          * one.  We have to set the data here instead of in
 589          * mdc_enqueue, because we need to use the child's inode as
 590          * the l_ast_data to match, and that's not available until
 591          * intent_finish has performed the iget().) */
 592         lock = ldlm_handle2lock(&lockh);
 593         if (lock) {
 594                 ldlm_policy_data_t policy = lock->l_policy_data;
 595                 LDLM_DEBUG(lock, "matching against this");
 596                 LDLM_LOCK_PUT(lock);
 597                 memcpy(&old_lock, &lockh, sizeof(lockh));
 598                 if (ldlm_lock_match(NULL, LDLM_FL_BLOCK_GRANTED, NULL,
 599                                     LDLM_IBITS, &policy, LCK_NL, &old_lock)) {
 600                         ldlm_lock_decref_and_cancel(&lockh,
 601                                                     it->d.lustre.it_lock_mode);
 602                         memcpy(&lockh, &old_lock, sizeof(old_lock));
 603                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 604                                sizeof(lockh));
 605                 }
 606         }
 607         CDEBUG(D_DENTRY, "D_IT dentry %*s intent: %s status %d disp %x rc %d\n",
 608                len, name, ldlm_it2str(it->it_op), it->d.lustre.it_status,
 609                it->d.lustre.it_disposition, rc);
 610
 611         RETURN(rc);
 612 }
 613 EXPORT_SYMBOL(mdc_intent_lock);