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                 return LCK_PR;
  81
  82         LBUG();
  83         RETURN(-EINVAL);
  84 }
  85
  86 int it_open_error(int phase, struct lookup_intent *it)
  87 {
  88         if (it_disposition(it, DISP_OPEN_OPEN)) {
  89                 if (phase == DISP_OPEN_OPEN)
  90                         return it->d.lustre.it_status;
  91                 else
  92                         return 0;
  93         }
  94
  95         if (it_disposition(it, DISP_OPEN_CREATE)) {
  96                 if (phase == DISP_OPEN_CREATE)
  97                         return it->d.lustre.it_status;
  98                 else
  99                         return 0;
 100         }
 101
 102         if (it_disposition(it, DISP_LOOKUP_EXECD)) {
 103                 if (phase == DISP_LOOKUP_EXECD)
 104                         return it->d.lustre.it_status;
 105                 else
 106                         return 0;
 107         }
 108
 109         if (it_disposition(it, DISP_IT_EXECD)) {
 110                 if (phase == DISP_IT_EXECD)
 111                         return it->d.lustre.it_status;
 112                 else
 113                         return 0;
 114         }
 115         CERROR("it disp: %X, status: %d\n", it->d.lustre.it_disposition,
 116                it->d.lustre.it_status);
 117         LBUG();
 118         return 0;
 119 }
 120 EXPORT_SYMBOL(it_open_error);
 121
 122 /* this must be called on a lockh that is known to have a referenced lock */
 123 void mdc_set_lock_data(__u64 *l, void *data)
 124 {
 125         struct ldlm_lock *lock;
 126         struct lustre_handle *lockh = (struct lustre_handle *)l;
 127         ENTRY;
 128
 129         if (!*l) {
 130                 EXIT;
 131                 return;
 132         }
 133
 134         lock = ldlm_handle2lock(lockh);
 135
 136         LASSERT(lock != NULL);
 137         l_lock(&lock->l_resource->lr_namespace->ns_lock);
 138 #ifdef __KERNEL__
 139         if (lock->l_ast_data && lock->l_ast_data != data) {
 140                 struct inode *new_inode = data;
 141                 struct inode *old_inode = lock->l_ast_data;
 142                 unsigned long state = old_inode->i_state & I_FREEING;
 143                 CERROR("Found existing inode %p/%lu/%u state %lu in lock: "
 144                        "setting data to %p/%lu/%u\n", old_inode,
 145                        old_inode->i_ino, old_inode->i_generation, state,
 146                        new_inode, new_inode->i_ino, new_inode->i_generation);
 147                 LASSERT(state);
 148         }
 149 #endif
 150         lock->l_ast_data = data;
 151         l_unlock(&lock->l_resource->lr_namespace->ns_lock);
 152         LDLM_LOCK_PUT(lock);
 153
 154         EXIT;
 155 }
 156 EXPORT_SYMBOL(mdc_set_lock_data);
 157
 158 int mdc_change_cbdata(struct obd_export *exp, struct ll_fid *fid,
 159                       ldlm_iterator_t it, void *data)
 160 {
 161         struct ldlm_res_id res_id = { .name = {0} };
 162         ENTRY;
 163
 164         res_id.name[0] = fid->id;
 165         res_id.name[1] = fid->generation;
 166
 167         ldlm_change_cbdata(class_exp2obd(exp)->obd_namespace, &res_id, it,
 168                            data);
 169         EXIT;
 170         return 0;
 171 }
 172
 173
 174
 175 /* We always reserve enough space in the reply packet for a stripe MD, because
 176  * we don't know in advance the file type. */
 177 int mdc_enqueue(struct obd_export *exp,
 178                 int lock_type,
 179                 struct lookup_intent *it,
 180                 int lock_mode,
 181                 struct mdc_op_data *data,
 182                 struct lustre_handle *lockh,
 183                 void *lmm,
 184                 int lmmsize,
 185                 ldlm_completion_callback cb_completion,
 186                 ldlm_blocking_callback cb_blocking,
 187                 void *cb_data)
 188 {
 189         struct ptlrpc_request *req;
 190         struct obd_device *obddev = class_exp2obd(exp);
 191         struct ldlm_res_id res_id =
 192                 { .name = {data->fid1.id, data->fid1.generation} };
 193         int size[6] = {sizeof(struct ldlm_request), sizeof(struct ldlm_intent)};
 194         int rc, flags = LDLM_FL_HAS_INTENT;
 195         int repsize[4] = {sizeof(struct ldlm_reply),
 196                           sizeof(struct mds_body),
 197                           obddev->u.cli.cl_max_mds_easize,
 198                           obddev->u.cli.cl_max_mds_cookiesize};
 199         struct ldlm_reply *dlm_rep;
 200         struct ldlm_intent *lit;
 201         struct ldlm_request *lockreq;
 202         void *eadata;
 203         unsigned long irqflags;
 204         int   reply_buffers = 0;
 205         ENTRY;
 206
 207 //        LDLM_DEBUG_NOLOCK("mdsintent=%s,name=%s,dir=%lu",
 208 //                          ldlm_it2str(it->it_op), it_name, it_inode->i_ino);
 209
 210         if (it->it_op & IT_OPEN) {
 211                 it->it_create_mode |= S_IFREG;
 212                 it->it_create_mode &= ~current->fs->umask;
 213
 214                 size[2] = sizeof(struct mds_rec_create);
 215                 size[3] = data->namelen + 1;
 216                 size[4] = obddev->u.cli.cl_max_mds_easize;
 217                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE,
 218                                       5, size, NULL);
 219                 if (!req)
 220                         RETURN(-ENOMEM);
 221
 222                 spin_lock_irqsave (&req->rq_lock, irqflags);
 223                 req->rq_replay = 1;
 224                 spin_unlock_irqrestore (&req->rq_lock, irqflags);
 225
 226                 /* pack the intent */
 227                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 228                 lit->opc = (__u64)it->it_op;
 229
 230                 /* pack the intended request */
 231                 mdc_open_pack(req, 2, data, it->it_create_mode, 0,
 232                               it->it_flags, lmm, lmmsize);
 233                 /* get ready for the reply */
 234                 reply_buffers = 3;
 235                 req->rq_replen = lustre_msg_size(3, repsize);
 236         } else if (it->it_op & IT_UNLINK) {
 237                 size[2] = sizeof(struct mds_rec_unlink);
 238                 size[3] = data->namelen + 1;
 239                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 4,
 240                                       size, NULL);
 241                 if (!req)
 242                         RETURN(-ENOMEM);
 243
 244                 /* pack the intent */
 245                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 246                 lit->opc = (__u64)it->it_op;
 247
 248                 /* pack the intended request */
 249                 mdc_unlink_pack(req, 2, data);
 250                 /* get ready for the reply */
 251                 reply_buffers = 4;
 252                 req->rq_replen = lustre_msg_size(4, repsize);
 253         } else if (it->it_op & (IT_GETATTR | IT_LOOKUP)) {
 254                 int valid = OBD_MD_FLNOTOBD | OBD_MD_FLEASIZE;
 255                 size[2] = sizeof(struct mds_body);
 256                 size[3] = data->namelen + 1;
 257
 258                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 4,
 259                                       size, NULL);
 260                 if (!req)
 261                         RETURN(-ENOMEM);
 262
 263                 /* pack the intent */
 264                 lit = lustre_msg_buf(req->rq_reqmsg, 1, sizeof (*lit));
 265                 lit->opc = (__u64)it->it_op;
 266
 267                 /* pack the intended request */
 268                 mdc_getattr_pack(req, valid, 2, it->it_flags, data);
 269                 /* get ready for the reply */
 270                 reply_buffers = 3;
 271                 req->rq_replen = lustre_msg_size(3, repsize);
 272         } else if (it->it_op == IT_READDIR) {
 273                 req = ptlrpc_prep_req(class_exp2cliimp(exp), LDLM_ENQUEUE, 1,
 274                                       size, NULL);
 275                 if (!req)
 276                         RETURN(-ENOMEM);
 277
 278                 /* get ready for the reply */
 279                 reply_buffers = 1;
 280                 req->rq_replen = lustre_msg_size(1, repsize);
 281         }  else {
 282                 LBUG();
 283                 RETURN(-EINVAL);
 284         }
 285
 286         mdc_get_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 287         rc = ldlm_cli_enqueue(exp, req, obddev->obd_namespace, res_id,
 288                               lock_type, NULL, lock_mode, &flags, cb_blocking,
 289                               cb_completion, NULL, cb_data, NULL, 0, NULL,
 290                               lockh);
 291         mdc_put_rpc_lock(obddev->u.cli.cl_rpc_lock, it);
 292
 293         /* Similarly, if we're going to replay this request, we don't want to
 294          * actually get a lock, just perform the intent. */
 295         if (req->rq_transno || req->rq_replay) {
 296                 lockreq = lustre_msg_buf(req->rq_reqmsg, 0, sizeof (*lockreq));
 297                 lockreq->lock_flags |= LDLM_FL_INTENT_ONLY;
 298         }
 299
 300         /* This can go when we're sure that this can never happen */
 301         LASSERT(rc != -ENOENT);
 302         if (rc == ELDLM_LOCK_ABORTED) {
 303                 lock_mode = 0;
 304                 memset(lockh, 0, sizeof(*lockh));
 305                 rc = 0;
 306         } else if (rc != 0) {
 307                 CERROR("ldlm_cli_enqueue: %d\n", rc);
 308                 LASSERT (rc < 0);
 309                 ptlrpc_req_finished(req);
 310                 RETURN(rc);
 311         } else { /* rc = 0 */
 312                 struct ldlm_lock *lock = ldlm_handle2lock(lockh);
 313                 LASSERT(lock);
 314
 315                 /* If the server gave us back a different lock mode, we should
 316                  * fix up our variables. */
 317                 if (lock->l_req_mode != lock_mode) {
 318                         ldlm_lock_addref(lockh, lock->l_req_mode);
 319                         ldlm_lock_decref(lockh, lock_mode);
 320                         lock_mode = lock->l_req_mode;
 321                 }
 322
 323                 ldlm_lock_allow_match(lock);
 324                 LDLM_LOCK_PUT(lock);
 325         }
 326
 327         dlm_rep = lustre_msg_buf(req->rq_repmsg, 0, sizeof (*dlm_rep));
 328         LASSERT(dlm_rep != NULL);           /* checked by ldlm_cli_enqueue() */
 329         LASSERT_REPSWABBED(req, 0);         /* swabbed by ldlm_cli_enqueue() */
 330
 331         it->d.lustre.it_disposition = (int) dlm_rep->lock_policy_res1;
 332         it->d.lustre.it_status = (int) dlm_rep->lock_policy_res2;
 333         it->d.lustre.it_lock_mode = lock_mode;
 334         it->d.lustre.it_data = req;
 335
 336         /* We know what to expect, so we do any byte flipping required here */
 337         LASSERT(reply_buffers == 4 || reply_buffers == 3 || reply_buffers == 1);
 338         if (reply_buffers >= 3) {
 339                 struct mds_body *body;
 340
 341                 body = lustre_swab_repbuf(req, 1, sizeof (*body),
 342                                            lustre_swab_mds_body);
 343                 if (body == NULL) {
 344                         CERROR ("Can't swab mds_body\n");
 345                         RETURN (-EPROTO);
 346                 }
 347
 348                 if ((body->valid & OBD_MD_FLEASIZE) != 0) {
 349                         void *replayea;
 350                         /* The eadata is opaque; just check that it is
 351                          * there.  Eventually, obd_unpackmd() will check
 352                          * the contents */
 353                         eadata = lustre_swab_repbuf(req, 2, body->eadatasize,
 354                                                     NULL);
 355                         if (eadata == NULL) {
 356                                 CERROR ("Missing/short eadata\n");
 357                                 RETURN (-EPROTO);
 358                         }
 359                         if (it->it_op & IT_OPEN) {
 360                                 replayea = lustre_msg_buf(req->rq_reqmsg, 4,
 361                                                           obddev->u.cli.cl_max_mds_easize);
 362                                 LASSERT(replayea);
 363                                 memcpy(replayea, eadata, body->eadatasize);
 364                         }
 365                 }
 366         }
 367
 368         RETURN(rc);
 369 }
 370 EXPORT_SYMBOL(mdc_enqueue);
 371
 372 /*
 373  * This long block is all about fixing up the lock and request state
 374  * so that it is correct as of the moment _before_ the operation was
 375  * applied; that way, the VFS will think that everything is normal and
 376  * call Lustre's regular VFS methods.
 377  *
 378  * If we're performing a creation, that means that unless the creation
 379  * failed with EEXIST, we should fake up a negative dentry.
 380  *
 381  * For everything else, we want to lookup to succeed.
 382  *
 383  * One additional note: if CREATE or OPEN succeeded, we add an extra
 384  * reference to the request because we need to keep it around until
 385  * ll_create/ll_open gets called.
 386  *
 387  * The server will return to us, in it_disposition, an indication of
 388  * exactly what d.lustre.it_status refers to.
 389  *
 390  * If DISP_OPEN_OPEN is set, then d.lustre.it_status refers to the open() call,
 391  * otherwise if DISP_OPEN_CREATE is set, then it status is the
 392  * creation failure mode.  In either case, one of DISP_LOOKUP_NEG or
 393  * DISP_LOOKUP_POS will be set, indicating whether the child lookup
 394  * was successful.
 395  *
 396  * Else, if DISP_LOOKUP_EXECD then d.lustre.it_status is the rc of the
 397  * child lookup.
 398  */
 399 int mdc_intent_lock(struct obd_export *exp, struct ll_uctxt *uctxt,
 400                     struct ll_fid *pfid, const char *name, int len,
 401                     void *lmm, int lmmsize,
 402                     struct ll_fid *cfid, struct lookup_intent *it, int flags,
 403                     struct ptlrpc_request **reqp,
 404                     ldlm_blocking_callback cb_blocking)
 405 {
 406         struct lustre_handle lockh;
 407         struct ptlrpc_request *request;
 408         int rc = 0;
 409         struct mds_body *mds_body;
 410         struct lustre_handle old_lock;
 411         struct ldlm_lock *lock;
 412         ENTRY;
 413         LASSERT(it);
 414
 415         CDEBUG(D_DLMTRACE, "name: %*s in %ld, intent: %s\n", len, name,
 416                (unsigned long) pfid->id, ldlm_it2str(it->it_op));
 417
 418         if (cfid && (it->it_op == IT_LOOKUP || it->it_op == IT_GETATTR)) {
 419                 /* We could just return 1 immediately, but since we should only
 420                  * be called in revalidate_it if we already have a lock, let's
 421                  * verify that. */
 422                 struct ldlm_res_id res_id ={.name = {cfid->id,
 423                                                      cfid->generation}};
 424                 struct lustre_handle lockh;
 425                 int mode, flags = LDLM_FL_BLOCK_GRANTED;
 426
 427                 mode = LCK_PR;
 428                 rc = ldlm_lock_match(exp->exp_obd->obd_namespace, flags,
 429                                      &res_id, LDLM_PLAIN, NULL, LCK_PR, &lockh);
 430                 if (!rc) {
 431                         mode = LCK_PW;
 432                         rc = ldlm_lock_match(exp->exp_obd->obd_namespace, flags,
 433                                              &res_id, LDLM_PLAIN, NULL, LCK_PW,
 434                                              &lockh);
 435                 }
 436                 if (rc) {
 437                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 438                                sizeof(lockh));
 439                         it->d.lustre.it_lock_mode = mode;
 440                 }
 441                 RETURN(rc);
 442         }
 443
 444         /* lookup_it may be called only after revalidate_it has run, because
 445          * revalidate_it cannot return errors, only zero.  Returning zero causes
 446          * this call to lookup, which *can* return an error.
 447          *
 448          * We only want to execute the request associated with the intent one
 449          * time, however, so don't send the request again.  Instead, skip past
 450          * this and use the request from revalidate.  In this case, revalidate
 451          * never dropped its reference, so the refcounts are all OK */
 452         if (!it_disposition(it, DISP_ENQ_COMPLETE)) {
 453                 struct mdc_op_data op_data;
 454                 mdc_fid2mdc_op_data(&op_data, uctxt, pfid, cfid, name, len, 0);
 455
 456                 rc = mdc_enqueue(exp, LDLM_PLAIN, it, it_to_lock_mode(it),
 457                                  &op_data, &lockh, lmm, lmmsize,
 458                                  ldlm_completion_ast, cb_blocking, NULL);
 459                 if (rc < 0)
 460                         RETURN(rc);
 461                 memcpy(&it->d.lustre.it_lock_handle, &lockh, sizeof(lockh));
 462         }
 463         request = *reqp = it->d.lustre.it_data;
 464         LASSERT(request != NULL);
 465
 466         if (!it_disposition(it, DISP_IT_EXECD)) {
 467                 /* The server failed before it even started executing the
 468                  * intent, i.e. because it couldn't unpack the request. */
 469                 LASSERT(it->d.lustre.it_status != 0);
 470                 RETURN(it->d.lustre.it_status);
 471         }
 472         rc = it_open_error(DISP_IT_EXECD, it);
 473         if (rc)
 474                 RETURN(rc);
 475
 476         mds_body = lustre_msg_buf(request->rq_repmsg, 1, sizeof(*mds_body));
 477         LASSERT(mds_body != NULL);           /* mdc_enqueue checked */
 478         LASSERT_REPSWABBED(request, 1); /* mdc_enqueue swabbed */
 479
 480         /* If we were revalidating a fid/name pair, mark the intent in
 481          * case we fail and get called again from lookup */
 482         if (cfid != NULL) {
 483                 it_set_disposition(it, DISP_ENQ_COMPLETE);
 484                 /* Also: did we find the same inode? */
 485                 if (memcmp(cfid, &mds_body->fid1, sizeof(*cfid)))
 486                         RETURN(-ESTALE);
 487         }
 488
 489         /* If we're doing an IT_OPEN which did not result in an actual
 490          * successful open, then we need to remove the bit which saves
 491          * this request for unconditional replay. */
 492         if (it->it_op & IT_OPEN) {
 493                 if (!it_disposition(it, DISP_OPEN_OPEN) ||
 494                     it->d.lustre.it_status != 0) {
 495                         unsigned long flags;
 496
 497                         spin_lock_irqsave(&request->rq_lock, flags);
 498                         request->rq_replay = 0;
 499                         spin_unlock_irqrestore(&request->rq_lock, flags);
 500                 }
 501         }
 502
 503         rc = it_open_error(DISP_LOOKUP_EXECD, it);
 504         if (rc)
 505                 RETURN(rc);
 506
 507         /* keep requests around for the multiple phases of the call
 508          * this shows the DISP_XX must guarantee we make it into the call
 509          */
 510         if (it_disposition(it, DISP_OPEN_CREATE) &&
 511             !it_open_error(DISP_OPEN_CREATE, it))
 512                 ptlrpc_request_addref(request);
 513         if (it_disposition(it, DISP_OPEN_OPEN) &&
 514             !it_open_error(DISP_OPEN_OPEN, it))
 515                 ptlrpc_request_addref(request);
 516
 517         if (it->it_op & IT_CREAT) {
 518                 /* XXX this belongs in ll_create_iit */
 519         } else if (it->it_op == IT_OPEN) {
 520                 LASSERT(!it_disposition(it, DISP_OPEN_CREATE));
 521         } else {
 522                 LASSERT(it->it_op & (IT_GETATTR | IT_LOOKUP));
 523         }
 524
 525         /* If we already have a matching lock, then cancel the new
 526          * one.  We have to set the data here instead of in
 527          * mdc_enqueue, because we need to use the child's inode as
 528          * the l_ast_data to match, and that's not available until
 529          * intent_finish has performed the iget().) */
 530         lock = ldlm_handle2lock(&lockh);
 531         if (lock) {
 532                 LDLM_DEBUG(lock, "matching against this");
 533                 LDLM_LOCK_PUT(lock);
 534                 memcpy(&old_lock, &lockh, sizeof(lockh));
 535                 if (ldlm_lock_match(NULL, LDLM_FL_BLOCK_GRANTED, NULL,
 536                                     LDLM_PLAIN, NULL, LCK_NL, &old_lock)) {
 537                         ldlm_lock_decref_and_cancel(&lockh,
 538                                                     it->d.lustre.it_lock_mode);
 539                         memcpy(&lockh, &old_lock, sizeof(old_lock));
 540                         memcpy(&it->d.lustre.it_lock_handle, &lockh,
 541                                sizeof(lockh));
 542                 }
 543         }
 544         CDEBUG(D_DENTRY, "D_IT dentry %*s intent: %s status %d disp %x rc %d\n",
 545                len, name, ldlm_it2str(it->it_op), it->d.lustre.it_status,
 546                it->d.lustre.it_disposition, rc);
 547
 548         RETURN(rc);
 549 }
 550 EXPORT_SYMBOL(mdc_intent_lock);