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_sec.h>
  40 #include <linux/lprocfs_status.h>
  41 #include <linux/lustre_acl.h>
  42 #include <linux/lustre_lite.h>
  43 #include "mdc_internal.h"
  44
  45 int it_disposition(struct lookup_intent *it, int flag)
  46 {
  47         return LUSTRE_IT(it)->it_disposition & flag;
  48 }
  49 EXPORT_SYMBOL(it_disposition);
  50
  51 void it_set_disposition(struct lookup_intent *it, int flag)
  52 {
  53         LUSTRE_IT(it)->it_disposition |= flag;
  54 }
  55 EXPORT_SYMBOL(it_set_disposition);
  56
  57 static void mdc_id2mdc_data(struct mdc_op_data *data,
  58                             struct lustre_id *f1,
  59                             struct lustre_id *f2,
  60                             const char *name,
  61                             int namelen, int mode)
  62 {
  63         LASSERT(data);
  64         LASSERT(f1);
  65
  66         data->id1 = *f1;
  67         if (f2)
  68                 data->id2 = *f2;
  69
  70         data->valid = 0;
  71         data->name = name;
  72         data->namelen = namelen;
  73         data->create_mode = mode;
  74         data->mod_time = LTIME_S(CURRENT_TIME);
  75 }
  76
  77 static int it_to_lock_mode(struct lookup_intent *it)
  78 {
  79         /* CREAT needs to be tested before open (both could be set) */
  80         if (it->it_op & IT_CREAT)
  81                 return LCK_PW;
  82         else if (it->it_op & (IT_READDIR | IT_GETATTR | IT_OPEN | IT_LOOKUP |
  83                               IT_CHDIR))
  84                 return LCK_PR;
  85
  86         LBUG();
  87         RETURN(-EINVAL);
  88 }
  89
  90 int it_open_error(int phase, struct lookup_intent *it)
  91 {
  92         if (it_disposition(it, DISP_OPEN_OPEN)) {
  93                 if (phase == DISP_OPEN_OPEN)
  94                         return LUSTRE_IT(it)->it_status;
  95                 else
  96                         return 0;
  97         }
  98
  99         if (it_disposition(it, DISP_OPEN_CREATE)) {
 100                 if (phase == DISP_OPEN_CREATE)
 101                         return LUSTRE_IT(it)->it_status;
 102                 else
 103                         return 0;
 104         }
 105
 106         if (it_disposition(it, DISP_LOOKUP_EXECD)) {
 107                 if (phase == DISP_LOOKUP_EXECD)
 108                         return LUSTRE_IT(it)->it_status;
 109                 else
 110                         return 0;
 111         }
 112
 113         if (it_disposition(it, DISP_IT_EXECD)) {
 114                 if (phase == DISP_IT_EXECD)
 115                         return LUSTRE_IT(it)->it_status;
 116                 else
 117                         return 0;
 118         }
 119         CERROR("it disp: %X, status: %d\n", LUSTRE_IT(it)->it_disposition,
 120                LUSTRE_IT(it)->it_status);
 121         LBUG();
 122         return 0;
 123 }
 124 EXPORT_SYMBOL(it_open_error);
 125
 126 /* this must be called on a lockh that is known to have a referenced lock */
 127 int mdc_set_lock_data(struct obd_export *exp, __u64 *l, void *data)
 128 {
 129         struct ldlm_lock *lock;
 130         struct lustre_handle *lockh = (struct lustre_handle *)l;
 131         ENTRY;
 132
 133         if (!*l) {
 134                 EXIT;
 135                 return 0;
 136         }
 137
 138         lock = ldlm_handle2lock(lockh);
 139
 140         LASSERT(lock != NULL);
 141         lock_res_and_lock(lock);
 142 #ifdef __KERNEL__
 143         if (lock->l_ast_data && lock->l_ast_data != data) {
 144                 struct inode *new_inode = data;
 145                 struct inode *old_inode = lock->l_ast_data;
 146                 LASSERTF(old_inode->i_state & I_FREEING,
 147                          "Found existing inode %p/%lu/%u state %lu in lock: "
 148                          "setting data to %p/%lu/%u\n", old_inode,
 149                          old_inode->i_ino, old_inode->i_generation,
 150                          old_inode->i_state, new_inode, new_inode->i_ino,
 151                          new_inode->i_generation);
 152         }
 153 #endif
 154         lock->l_ast_data = data;
 155         unlock_res_and_lock(lock);
 156         LDLM_LOCK_PUT(lock);
 157
 158         EXIT;
 159         return 0;
 160 }
 161 EXPORT_SYMBOL(mdc_set_lock_data);
 162
 163 int mdc_change_cbdata(struct obd_export *exp, struct lustre_id *id,
 164                       ldlm_iterator_t it, void *data)
 165 {
 166         struct ldlm_res_id res_id = { .name = {0} };
 167         ENTRY;
 168
 169         res_id.name[0] = id_fid(id);
 170         res_id.name[1] = id_group(id);
 171
 172         ldlm_change_cbdata(class_exp2obd(exp)->obd_namespace,
 173                            &res_id, it, data);
 174
 175         EXIT;
 176         return 0;
 177 }
 178
 179 static inline void
 180 mdc_clear_replay_flag(struct ptlrpc_request *req, int rc)
 181 {
 182         /* Don't hold error requests for replay. */
 183         if (req->rq_replay) {
 184                 unsigned long irqflags;
 185                 spin_lock_irqsave(&req->rq_lock, irqflags);
 186                 req->rq_replay = 0;
 187                 spin_unlock_irqrestore(&req->rq_lock, irqflags);
 188         }
 189         if (rc && req->rq_transno != 0) {
 190                 DEBUG_REQ(D_ERROR, req, "transno returned on error rc %d", rc);
 191                 LBUG();
 192         }
 193 }
 194
 195 /* We always reserve enough space in the reply packet for a stripe MD, because
 196  * we don't know in advance the file type. */
 197 int mdc_enqueue(struct obd_export *exp,
 198                 int lock_type,
 199                 struct lookup_intent *it,
 200                 int lock_mode,
 201                 struct mdc_op_data *data,
 202                 struct lustre_handle *lockh,
 203                 void *lmm,
 204                 int lmmsize,
 205                 ldlm_completion_callback cb_completion,
 206                 ldlm_blocking_callback cb_blocking,
 207                 void *cb_data)
 208 {
 209         struct ptlrpc_request *req;
 210         struct ldlm_res_id res_id = {
 211                 .name = {id_fid(&data->id1), id_group(&data->id1)}
 212         };
 213         struct obd_device *obddev = class_exp2obd(exp);
 214         ldlm_policy_data_t policy = { .l_inodebits = { MDS_INODELOCK_LOOKUP } };
 215         struct ldlm_intent *lit;
 216         struct ldlm_request *lockreq;
 217         int reqsize[6] = {[MDS_REQ_SECDESC_OFF] = 0,
 218                           [MDS_REQ_INTENT_LOCKREQ_OFF] = sizeof(*lockreq),
 219                           [MDS_REQ_INTENT_IT_OFF] = sizeof(*lit)};
 220         int repsize[5] = {sizeof(struct ldlm_reply),
 221                           sizeof(struct mds_body),
 222                           obddev->u.cli.cl_max_mds_easize};
 223         int req_buffers = 3, reply_buffers = 0;
 224         int rc, flags = LDLM_FL_HAS_INTENT;
 225         struct ldlm_reply *dlm_rep = NULL;
 226         void *eadata;
 227         unsigned long irqflags;
 228         ENTRY;
 229
 230 //        LDLM_DEBUG_NOLOCK("mdsintent=%s,name=%s,dir=%lu",
 231 //                          ldlm_it2str(it->it_op), it_name, it_inode->i_ino);
 232
 233         reqsize[0] = lustre_secdesc_size();
 234
 235         if (it->it_op & IT_OPEN) {
 236                 it->it_create_mode |= S_IFREG;
 237                 it->it_create_mode &= ~current->fs->umask;
 238
 239                 reqsize[req_buffers++] = sizeof(struct mds_rec_create);
 240                 reqsize[req_buffers++] = data->namelen + 1;
 241                 reqsize[req_buffers++] = obddev->u.cli.cl_max_mds_easize;
 242
 243                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LUSTRE_DLM_VERSION,
 244                                       LDLM_ENQUEUE, req_buffers, reqsize, NULL);
 245                 if (!req)
 246                         RETURN(-ENOMEM);
 247
 248                 spin_lock_irqsave (&req->rq_lock, irqflags);
 249                 req->rq_replay = 1;
 250                 spin_unlock_irqrestore (&req->rq_lock, irqflags);
 251
 252                 /* pack the intent */
 253                 lit = lustre_msg_buf(req->rq_reqmsg, MDS_REQ_INTENT_IT_OFF,
 254                                      sizeof (*lit));
 255                 lit->opc = (__u64)it->it_op;
 256
 257                 /* pack the intended request */
 258                 mdc_open_pack(req->rq_reqmsg, MDS_REQ_INTENT_REC_OFF, data,
 259                               it->it_create_mode, 0, it->it_flags, lmm, lmmsize);
 260                 /* get ready for the reply */
 261                 repsize[3] = 4;
 262                 repsize[4] = xattr_acl_size(LL_ACL_MAX_ENTRIES);
 263                 reply_buffers = 5;
 264                 req->rq_replen = lustre_msg_size(5, repsize);
 265         } else if (it->it_op & (IT_GETATTR | IT_LOOKUP | IT_CHDIR)) {
 266                 __u64 valid = data->valid | OBD_MD_FLNOTOBD | OBD_MD_FLEASIZE |
 267                             OBD_MD_FLACL_ACCESS;
 268
 269                 reqsize[req_buffers++] = sizeof(struct mds_body);
 270                 reqsize[req_buffers++] = data->namelen + 1;
 271
 272                 if (it->it_op & IT_GETATTR)
 273                         policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 274
 275                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LUSTRE_DLM_VERSION,
 276                                       LDLM_ENQUEUE, req_buffers, reqsize, NULL);
 277
 278                 if (!req)
 279                         RETURN(-ENOMEM);
 280
 281                 /* pack the intent */
 282                 lit = lustre_msg_buf(req->rq_reqmsg, MDS_REQ_INTENT_IT_OFF,
 283                                      sizeof (*lit));
 284                 lit->opc = (__u64)it->it_op;
 285
 286                 /* pack the intended request */
 287                 mdc_getattr_pack(req->rq_reqmsg, MDS_REQ_INTENT_REC_OFF,
 288                                  valid, it->it_flags, data);
 289
 290                 /* get ready for the reply */
 291                 repsize[3] = 4;
 292                 repsize[4] = xattr_acl_size(LL_ACL_MAX_ENTRIES);
 293                 reply_buffers = 5;
 294                 req->rq_replen = lustre_msg_size(5, repsize);
 295         } else if (it->it_op == IT_READDIR) {
 296                 policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 297                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LUSTRE_DLM_VERSION,
 298                                       LDLM_ENQUEUE, 2, reqsize, NULL);
 299
 300                 if (!req)
 301                         RETURN(-ENOMEM);
 302                 /* get ready for the reply */
 303                 reply_buffers = 1;
 304                 req->rq_replen = lustre_msg_size(1, repsize);
 305         } else if (it->it_op == IT_UNLINK) {
 306                 reqsize[req_buffers++] = sizeof(struct mds_body);
 307                 policy.l_inodebits.bits = MDS_INODELOCK_UPDATE;
 308                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LUSTRE_DLM_VERSION,
 309                                       LDLM_ENQUEUE, req_buffers, reqsize, NULL);
 310                 if (!req)
 311                         RETURN(-ENOMEM);
 312
 313                 /* pack the intended request */
 314                 mdc_getattr_pack(req->rq_reqmsg, MDS_REQ_INTENT_REC_OFF,
 315                                  0, 0, data);
 316
 317                 /* pack the intent */
 318                 lit = lustre_msg_buf(req->rq_reqmsg, MDS_REQ_INTENT_IT_OFF,
 319                                      sizeof (*lit));
 320                 lit->opc = (__u64)it->it_op;
 321
 322                 /* get ready for the reply */
 323                 reply_buffers = 3;
 324                 req->rq_replen = lustre_msg_size(3, repsize);
 325         } else {
 326                 LBUG();
 327                 RETURN(-EINVAL);
 328         }
 329
 330         lustre_pack_secdesc(req, reqsize[0]);
 331
 332         mdc_get_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 333         rc = ldlm_cli_enqueue(exp, req, obddev->obd_namespace, res_id,
 334                               lock_type, &policy, lock_mode, &flags,cb_blocking,
 335                               cb_completion, NULL, cb_data, NULL, 0, NULL,
 336                               lockh);
 337         mdc_put_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 338
 339         /* Similarly, if we're going to replay this request, we don't want to
 340          * actually get a lock, just perform the intent. */
 341         if (req->rq_transno || req->rq_replay) {
 342                 lockreq = lustre_msg_buf(req->rq_reqmsg,
 343                                          MDS_REQ_INTENT_LOCKREQ_OFF,
 344                                          sizeof (*lockreq));
 345                 lockreq->lock_flags |= LDLM_FL_INTENT_ONLY;
 346         }
 347
 348         /* This can go when we're sure that this can never happen */
 349         LASSERT(rc != -ENOENT);
 350         /* We need dlm_rep to be assigned this early, to check lock mode of
 351            returned lock from request to avoid possible race with lock
 352            conversion */
 353         if (rc == ELDLM_LOCK_ABORTED || !rc) {
 354                 dlm_rep = lustre_msg_buf(req->rq_repmsg, 0, sizeof (*dlm_rep));
 355                 LASSERT(dlm_rep != NULL);   /* checked by ldlm_cli_enqueue() */
 356         }
 357         if (rc == ELDLM_LOCK_ABORTED) {
 358                 lock_mode = 0;
 359                 memset(lockh, 0, sizeof(*lockh));
 360                 rc = 0;
 361         } else if (rc != 0) {
 362                 CERROR("ldlm_cli_enqueue: %d\n", rc);
 363                 LASSERTF(rc < 0, "rc = %d\n", rc);
 364                 mdc_clear_replay_flag(req, rc);
 365                 ptlrpc_req_finished(req);
 366                 RETURN(rc);
 367         } else { /* rc = 0 */
 368                 struct ldlm_lock *lock = ldlm_handle2lock(lockh);
 369                 LASSERT(lock);
 370
 371                 /* If the server gave us back a different lock mode, we should
 372                  * fix up our variables. */
 373                 if (dlm_rep->lock_desc.l_req_mode != lock_mode) {
 374                         ldlm_lock_addref(lockh, dlm_rep->lock_desc.l_req_mode);
 375                         ldlm_lock_decref(lockh, lock_mode);
 376                         lock_mode = dlm_rep->lock_desc.l_req_mode;
 377                 }
 378
 379                 ldlm_lock_allow_match(lock);
 380                 LDLM_LOCK_PUT(lock);
 381         }
 382
 383         LASSERT_REPSWABBED(req, 0);         /* swabbed by ldlm_cli_enqueue() */
 384
 385         LUSTRE_IT(it)->it_disposition = (int) dlm_rep->lock_policy_res1;
 386         LUSTRE_IT(it)->it_status = (int) dlm_rep->lock_policy_res2;
 387         LUSTRE_IT(it)->it_lock_mode = lock_mode;
 388         LUSTRE_IT(it)->it_data = req;
 389
 390         if (LUSTRE_IT(it)->it_status < 0 && req->rq_replay)
 391                 mdc_clear_replay_flag(req, LUSTRE_IT(it)->it_status);
 392
 393         DEBUG_REQ(D_DLMTRACE, req, "disposition: %x, status: %d",
 394                   LUSTRE_IT(it)->it_disposition, LUSTRE_IT(it)->it_status);
 395
 396         /* We know what to expect, so we do any byte flipping required here */
 397         LASSERT(reply_buffers == 5 || reply_buffers == 4 ||
 398                 reply_buffers == 3 || reply_buffers == 1);
 399         if (reply_buffers >= 3) {
 400                 struct mds_body *body;
 401
 402                 body = lustre_swab_repbuf(req, 1, sizeof (*body),
 403                                           lustre_swab_mds_body);
 404                 if (body == NULL) {
 405                         CERROR ("Can't swab mds_body\n");
 406                         RETURN (-EPROTO);
 407                 }
 408
 409                 if ((body->valid & OBD_MD_FLEASIZE) != 0) {
 410                         /* The eadata is opaque; just check that it is there.
 411                          * Eventually, obd_unpackmd() will check the contents */
 412                         eadata = lustre_swab_repbuf(req, 2, body->eadatasize,
 413                                                     NULL);
 414                         if (eadata == NULL) {
 415                                 CERROR ("Missing/short eadata\n");
 416                                 RETURN (-EPROTO);
 417                         }
 418                         if (it->it_op & IT_OPEN) {
 419                                 void *replayea;
 420
 421                                 replayea = lustre_msg_buf(req->rq_reqmsg,
 422                                                           MDS_REQ_INTENT_REC_OFF + 2,
 423                                                           body->eadatasize);
 424                                 LASSERT(replayea);
 425                                 memcpy(replayea, eadata, body->eadatasize);
 426
 427                                 LASSERT(req->rq_reqmsg->bufcount == 6);
 428                                 req->rq_reqmsg->buflens[5] = body->eadatasize;
 429                                 /* If this isn't the last buffer, we might
 430                                  * have to shift other data around. */
 431                         }
 432                 }
 433         }
 434
 435         RETURN(rc);
 436 }
 437 EXPORT_SYMBOL(mdc_enqueue);
 438
 439 /*
 440  * This long block is all about fixing up the lock and request state
 441  * so that it is correct as of the moment _before_ the operation was
 442  * applied; that way, the VFS will think that everything is normal and
 443  * call Lustre's regular VFS methods.
 444  *
 445  * If we're performing a creation, that means that unless the creation
 446  * failed with EEXIST, we should fake up a negative dentry.
 447  *
 448  * For everything else, we want to lookup to succeed.
 449  *
 450  * One additional note: if CREATE or OPEN succeeded, we add an extra
 451  * reference to the request because we need to keep it around until
 452  * ll_create/ll_open gets called.
 453  *
 454  * The server will return to us, in it_disposition, an indication of
 455  * exactly what d.lustre->it_status refers to.
 456  *
 457  * If DISP_OPEN_OPEN is set, then d.lustre->it_status refers to the open() call,
 458  * otherwise if DISP_OPEN_CREATE is set, then it status is the
 459  * creation failure mode.  In either case, one of DISP_LOOKUP_NEG or
 460  * DISP_LOOKUP_POS will be set, indicating whether the child lookup
 461  * was successful.
 462  *
 463  * Else, if DISP_LOOKUP_EXECD then d.lustre->it_status is the rc of the
 464  * child lookup.
 465  */
 466 int mdc_intent_lock(struct obd_export *exp, struct lustre_id *pid,
 467                     const char *name, int len, void *lmm, int lmmsize,
 468                     struct lustre_id *cid, struct lookup_intent *it,
 469                     int lookup_flags, struct ptlrpc_request **reqp,
 470                     ldlm_blocking_callback cb_blocking)
 471 {
 472         struct lustre_handle lockh;
 473         struct ptlrpc_request *request;
 474         struct mds_body *mds_body;
 475         struct lustre_handle old_lock;
 476         struct ldlm_lock *lock;
 477         int rc = 0;
 478         ENTRY;
 479         LASSERT(it);
 480
 481         CDEBUG(D_DLMTRACE, "name: %*s in obj "DLID4", intent: %s flags %#o\n",
 482                len, name, OLID4(pid), ldlm_it2str(it->it_op), it->it_flags);
 483
 484         if (cid && (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR ||
 485                     it->it_op == IT_CHDIR)) {
 486                 /* We could just return 1 immediately, but since we should only
 487                  * be called in revalidate_it if we already have a lock, let's
 488                  * verify that. */
 489                 struct ldlm_res_id res_id = {.name = {id_fid(cid),
 490                                                       id_group(cid)}};
 491                 struct lustre_handle lockh;
 492                 ldlm_policy_data_t policy;
 493                 int mode;
 494
 495                 /* For the GETATTR case, ll_revalidate_it issues two separate
 496                    queries - for LOOKUP and for UPDATE lock because it cannot
 497                    check them together - we might have those two bits to be
 498                    present in two separate granted locks */
 499                 policy.l_inodebits.bits = (it->it_op == IT_GETATTR) ?
 500                         MDS_INODELOCK_UPDATE : MDS_INODELOCK_LOOKUP;
 501
 502                 mode = LCK_PR;
 503                 rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 504                                      LDLM_FL_BLOCK_GRANTED, &res_id,
 505                                      LDLM_IBITS, &policy, mode,
 506                                      &lockh);
 507
 508                 if (!rc) {
 509                         mode = LCK_CR;
 510                         rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 511                                              LDLM_FL_BLOCK_GRANTED, &res_id,
 512                                              LDLM_IBITS, &policy, mode,
 513                                              &lockh);
 514                 }
 515                 if (!rc) {
 516                         mode = LCK_PW;
 517                         rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 518                                              LDLM_FL_BLOCK_GRANTED, &res_id,
 519                                              LDLM_IBITS, &policy, mode,
 520                                              &lockh);
 521                 }
 522                 if (!rc) {
 523                         mode = LCK_CW;
 524                         rc = ldlm_lock_match(exp->exp_obd->obd_namespace,
 525                                              LDLM_FL_BLOCK_GRANTED, &res_id,
 526                                              LDLM_IBITS, &policy, mode,
 527                                              &lockh);
 528                 }
 529                 if (rc) {
 530                         if (ptlrpcs_check_cred(exp->exp_obd->u.cli.cl_import)) {
 531                                 /* return immediately if no credential held */
 532                                 ldlm_lock_decref(&lockh, mode);
 533                                 RETURN(-EACCES);
 534                         }
 535                         memcpy(&LUSTRE_IT(it)->it_lock_handle, &lockh,
 536                                sizeof(lockh));
 537                         LUSTRE_IT(it)->it_lock_mode = mode;
 538                 }
 539
 540                 /* Only return failure if it was not GETATTR by cid (from
 541                    inode_revalidate) */
 542                 if (rc || name)
 543                         RETURN(rc);
 544         }
 545
 546         /* lookup_it may be called only after revalidate_it has run, because
 547          * revalidate_it cannot return errors, only zero.  Returning zero causes
 548          * this call to lookup, which *can* return an error.
 549          *
 550          * We only want to execute the request associated with the intent one
 551          * time, however, so don't send the request again.  Instead, skip past
 552          * this and use the request from revalidate.  In this case, revalidate
 553          * never dropped its reference, so the refcounts are all OK */
 554         if (!it_disposition(it, DISP_ENQ_COMPLETE)) {
 555                 struct mdc_op_data *op_data;
 556
 557                 OBD_ALLOC(op_data, sizeof(*op_data));
 558                 if (op_data == NULL)
 559                         RETURN(-ENOMEM);
 560
 561                 mdc_id2mdc_data(op_data, pid, cid, name, len, 0);
 562
 563                 if (name != NULL)
 564                         op_data->valid |= OBD_MD_FID;
 565
 566                 rc = mdc_enqueue(exp, LDLM_IBITS, it, it_to_lock_mode(it),
 567                                  op_data, &lockh, lmm, lmmsize,
 568                                  ldlm_completion_ast, cb_blocking, NULL);
 569                 OBD_FREE(op_data, sizeof(*op_data));
 570                 if (rc < 0)
 571                         RETURN(rc);
 572
 573                 memcpy(&LUSTRE_IT(it)->it_lock_handle, &lockh, sizeof(lockh));
 574         }
 575         request = *reqp = LUSTRE_IT(it)->it_data;
 576         LASSERT(request != NULL);
 577
 578         /* If we're doing an IT_OPEN which did not result in an actual
 579          * successful open, then we need to remove the bit which saves this
 580          * request for unconditional replay.
 581          *
 582          * It's important that we do this first!  Otherwise we might exit the
 583          * function without doing so, and try to replay a failed create (bug
 584          * 3440) */
 585         if (it->it_op & IT_OPEN && request->rq_replay &&
 586             (!it_disposition(it, DISP_OPEN_OPEN) || LUSTRE_IT(it)->it_status != 0))
 587                 mdc_clear_replay_flag(request, LUSTRE_IT(it)->it_status);
 588
 589         if (!it_disposition(it, DISP_IT_EXECD)) {
 590                 /* The server failed before it even started executing the
 591                  * intent, i.e. because it couldn't unpack the request. */
 592                 LASSERT(LUSTRE_IT(it)->it_status != 0);
 593                 RETURN(LUSTRE_IT(it)->it_status);
 594         }
 595         rc = it_open_error(DISP_IT_EXECD, it);
 596         if (rc)
 597                 RETURN(rc);
 598
 599         mds_body = lustre_msg_buf(request->rq_repmsg, 1, sizeof(*mds_body));
 600         LASSERT(mds_body != NULL);      /* mdc_enqueue checked */
 601         LASSERT_REPSWABBED(request, 1); /* mdc_enqueue swabbed */
 602
 603         /* If we were revalidating a fid/name pair, mark the intent in case we
 604          * fail and get called again from lookup */
 605         if (cid != NULL) {
 606                 it_set_disposition(it, DISP_ENQ_COMPLETE);
 607                 /* Also: did we find the same inode? */
 608
 609                 /* we have to compare all the fields but type, because MDS can
 610                  * return fid/mds/ino/gen if inode lives on another MDS -bzzz */
 611                 if (!(lookup_flags & LOOKUP_COBD) && !id_equal(cid, &mds_body->id1))
 612                         RETURN(-ESTALE);
 613         }
 614
 615         rc = it_open_error(DISP_LOOKUP_EXECD, it);
 616         if (rc)
 617                 RETURN(rc);
 618
 619         /*
 620          * keep requests around for the multiple phases of the call this shows
 621          * the DISP_XX must guarantee we make it into the call.
 622          */
 623         if (it_disposition(it, DISP_OPEN_CREATE) &&
 624             !it_open_error(DISP_OPEN_CREATE, it))
 625                 ptlrpc_request_addref(request); /* balanced in ll_create_node */
 626         if (it_disposition(it, DISP_OPEN_OPEN) &&
 627             !it_open_error(DISP_OPEN_OPEN, it))
 628                 ptlrpc_request_addref(request); /* balanced in ll_file_open */
 629
 630         if (it->it_op & IT_CREAT) {
 631                 /* XXX this belongs in ll_create_it */
 632         } else if (it->it_op == IT_OPEN) {
 633                 LASSERT(!it_disposition(it, DISP_OPEN_CREATE));
 634         } else {
 635                 LASSERT(it->it_op & (IT_GETATTR | IT_LOOKUP | IT_CHDIR));
 636         }
 637
 638         /*
 639          * if we already have a matching lock, then cancel the new one. We have
 640          * to set the data here instead of in mdc_enqueue, because we need to
 641          * use the child's inode as the l_ast_data to match, and that's not
 642          * available until intent_finish has performed the iget().)
 643          */
 644         lock = ldlm_handle2lock(&lockh);
 645         if (lock) {
 646                 ldlm_policy_data_t policy = lock->l_policy_data;
 647                 LDLM_DEBUG(lock, "matching against this");
 648                 LDLM_LOCK_PUT(lock);
 649
 650                 LASSERTF(id_fid(&mds_body->id1) == lock->l_resource->lr_name.name[0] &&
 651                          id_group(&mds_body->id1) == lock->l_resource->lr_name.name[1],
 652                          "Invalid lock is returned to client. Lock res_is: %lu/%lu, "
 653                          "response res_id: %lu/%lu.\n",
 654                          (unsigned long)lock->l_resource->lr_name.name[0],
 655                          (unsigned long)lock->l_resource->lr_name.name[1],
 656                          (unsigned long)id_fid(&mds_body->id1),
 657                          (unsigned long)id_group(&mds_body->id1));
 658
 659                 memcpy(&old_lock, &lockh, sizeof(lockh));
 660                 if (ldlm_lock_match(NULL, LDLM_FL_BLOCK_GRANTED, NULL,
 661                                     LDLM_IBITS, &policy, LCK_NL, &old_lock)) {
 662                         ldlm_lock_decref_and_cancel(&lockh,
 663                                                     LUSTRE_IT(it)->it_lock_mode);
 664                         memcpy(&lockh, &old_lock, sizeof(old_lock));
 665                         memcpy(&LUSTRE_IT(it)->it_lock_handle, &lockh,
 666                                sizeof(lockh));
 667                 }
 668         }
 669         CDEBUG(D_DENTRY, "D_IT dentry %*s intent: %s status %d disp %x rc %d\n",
 670                len, name, ldlm_it2str(it->it_op), LUSTRE_IT(it)->it_status,
 671                LUSTRE_IT(it)->it_disposition, rc);
 672
 673         RETURN(rc);
 674 }
 675 EXPORT_SYMBOL(mdc_intent_lock);