fs/nfs/delegation.c

   1 /*
   2  * linux/fs/nfs/delegation.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFS file delegation management
   7  *
   8  */
   9 #include <linux/completion.h>
  10 #include <linux/kthread.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15
  16 #include <linux/nfs4.h>
  17 #include <linux/nfs_fs.h>
  18 #include <linux/nfs_xdr.h>
  19
  20 #include "nfs4_fs.h"
  21 #include "delegation.h"
  22 #include "internal.h"
  23 #include "nfs4trace.h"
  24
  25 static void nfs_free_delegation(struct nfs_delegation *delegation)
  26 {
  27         if (delegation->cred) {
  28                 put_rpccred(delegation->cred);
  29                 delegation->cred = NULL;
  30         }
  31         kfree_rcu(delegation, rcu);
  32 }
  33
  34 /**
  35  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
  36  * @delegation: delegation to process
  37  *
  38  */
  39 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  40 {
  41         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  42 }
  43
  44 static bool
  45 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
  46                 fmode_t flags)
  47 {
  48         if (delegation != NULL && (delegation->type & flags) == flags &&
  49             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
  50             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
  51                 return true;
  52         return false;
  53 }
  54
  55 static int
  56 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  57 {
  58         struct nfs_delegation *delegation;
  59         int ret = 0;
  60
  61         flags &= FMODE_READ|FMODE_WRITE;
  62         rcu_read_lock();
  63         delegation = rcu_dereference(NFS_I(inode)->delegation);
  64         if (nfs4_is_valid_delegation(delegation, flags)) {
  65                 if (mark)
  66                         nfs_mark_delegation_referenced(delegation);
  67                 ret = 1;
  68         }
  69         rcu_read_unlock();
  70         return ret;
  71 }
  72 /**
  73  * nfs_have_delegation - check if inode has a delegation, mark it
  74  * NFS_DELEGATION_REFERENCED if there is one.
  75  * @inode: inode to check
  76  * @flags: delegation types to check for
  77  *
  78  * Returns one if inode has the indicated delegation, otherwise zero.
  79  */
  80 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  81 {
  82         return nfs4_do_check_delegation(inode, flags, true);
  83 }
  84
  85 /*
  86  * nfs4_check_delegation - check if inode has a delegation, do not mark
  87  * NFS_DELEGATION_REFERENCED if it has one.
  88  */
  89 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
  90 {
  91         return nfs4_do_check_delegation(inode, flags, false);
  92 }
  93
  94 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
  95 {
  96         struct inode *inode = state->inode;
  97         struct file_lock *fl;
  98         struct file_lock_context *flctx = inode->i_flctx;
  99         struct list_head *list;
 100         int status = 0;
 101
 102         if (flctx == NULL)
 103                 goto out;
 104
 105         list = &flctx->flc_posix;
 106         spin_lock(&flctx->flc_lock);
 107 restart:
 108         list_for_each_entry(fl, list, fl_list) {
 109                 if (nfs_file_open_context(fl->fl_file) != ctx)
 110                         continue;
 111                 spin_unlock(&flctx->flc_lock);
 112                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 113                 if (status < 0)
 114                         goto out;
 115                 spin_lock(&flctx->flc_lock);
 116         }
 117         if (list == &flctx->flc_posix) {
 118                 list = &flctx->flc_flock;
 119                 goto restart;
 120         }
 121         spin_unlock(&flctx->flc_lock);
 122 out:
 123         return status;
 124 }
 125
 126 static int nfs_delegation_claim_opens(struct inode *inode,
 127                 const nfs4_stateid *stateid, fmode_t type)
 128 {
 129         struct nfs_inode *nfsi = NFS_I(inode);
 130         struct nfs_open_context *ctx;
 131         struct nfs4_state_owner *sp;
 132         struct nfs4_state *state;
 133         unsigned int seq;
 134         int err;
 135
 136 again:
 137         spin_lock(&inode->i_lock);
 138         list_for_each_entry(ctx, &nfsi->open_files, list) {
 139                 state = ctx->state;
 140                 if (state == NULL)
 141                         continue;
 142                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 143                         continue;
 144                 if (!nfs4_valid_open_stateid(state))
 145                         continue;
 146                 if (!nfs4_stateid_match(&state->stateid, stateid))
 147                         continue;
 148                 get_nfs_open_context(ctx);
 149                 spin_unlock(&inode->i_lock);
 150                 sp = state->owner;
 151                 /* Block nfs4_proc_unlck */
 152                 mutex_lock(&sp->so_delegreturn_mutex);
 153                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 154                 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
 155                 if (!err)
 156                         err = nfs_delegation_claim_locks(ctx, state, stateid);
 157                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 158                         err = -EAGAIN;
 159                 mutex_unlock(&sp->so_delegreturn_mutex);
 160                 put_nfs_open_context(ctx);
 161                 if (err != 0)
 162                         return err;
 163                 goto again;
 164         }
 165         spin_unlock(&inode->i_lock);
 166         return 0;
 167 }
 168
 169 /**
 170  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 171  * @inode: inode to process
 172  * @cred: credential to use for request
 173  * @res: new delegation state from server
 174  *
 175  */
 176 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
 177                                   struct nfs_openres *res)
 178 {
 179         struct nfs_delegation *delegation;
 180         struct rpc_cred *oldcred = NULL;
 181
 182         rcu_read_lock();
 183         delegation = rcu_dereference(NFS_I(inode)->delegation);
 184         if (delegation != NULL) {
 185                 spin_lock(&delegation->lock);
 186                 if (delegation->inode != NULL) {
 187                         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 188                         delegation->type = res->delegation_type;
 189                         delegation->pagemod_limit = res->pagemod_limit;
 190                         oldcred = delegation->cred;
 191                         delegation->cred = get_rpccred(cred);
 192                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 193                                   &delegation->flags);
 194                         spin_unlock(&delegation->lock);
 195                         rcu_read_unlock();
 196                         put_rpccred(oldcred);
 197                         trace_nfs4_reclaim_delegation(inode, res->delegation_type);
 198                         return;
 199                 }
 200                 /* We appear to have raced with a delegation return. */
 201                 spin_unlock(&delegation->lock);
 202         }
 203         rcu_read_unlock();
 204         nfs_inode_set_delegation(inode, cred, res);
 205 }
 206
 207 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 208 {
 209         int res = 0;
 210
 211         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 212                 res = nfs4_proc_delegreturn(inode,
 213                                 delegation->cred,
 214                                 &delegation->stateid,
 215                                 issync);
 216         nfs_free_delegation(delegation);
 217         return res;
 218 }
 219
 220 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 221 {
 222         struct inode *inode = NULL;
 223
 224         spin_lock(&delegation->lock);
 225         if (delegation->inode != NULL)
 226                 inode = igrab(delegation->inode);
 227         spin_unlock(&delegation->lock);
 228         return inode;
 229 }
 230
 231 static struct nfs_delegation *
 232 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 233 {
 234         struct nfs_delegation *ret = NULL;
 235         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 236
 237         if (delegation == NULL)
 238                 goto out;
 239         spin_lock(&delegation->lock);
 240         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 241                 ret = delegation;
 242         spin_unlock(&delegation->lock);
 243 out:
 244         return ret;
 245 }
 246
 247 static struct nfs_delegation *
 248 nfs_start_delegation_return(struct nfs_inode *nfsi)
 249 {
 250         struct nfs_delegation *delegation;
 251
 252         rcu_read_lock();
 253         delegation = nfs_start_delegation_return_locked(nfsi);
 254         rcu_read_unlock();
 255         return delegation;
 256 }
 257
 258 static void
 259 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 260                 struct nfs_client *clp)
 261 {
 262
 263         spin_lock(&delegation->lock);
 264         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 265         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 266         spin_unlock(&delegation->lock);
 267         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 268 }
 269
 270 static struct nfs_delegation *
 271 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 272                 struct nfs_delegation *delegation,
 273                 struct nfs_client *clp)
 274 {
 275         struct nfs_delegation *deleg_cur =
 276                 rcu_dereference_protected(nfsi->delegation,
 277                                 lockdep_is_held(&clp->cl_lock));
 278
 279         if (deleg_cur == NULL || delegation != deleg_cur)
 280                 return NULL;
 281
 282         spin_lock(&delegation->lock);
 283         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 284         list_del_rcu(&delegation->super_list);
 285         delegation->inode = NULL;
 286         rcu_assign_pointer(nfsi->delegation, NULL);
 287         spin_unlock(&delegation->lock);
 288         return delegation;
 289 }
 290
 291 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 292                 struct nfs_delegation *delegation,
 293                 struct nfs_server *server)
 294 {
 295         struct nfs_client *clp = server->nfs_client;
 296
 297         spin_lock(&clp->cl_lock);
 298         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 299         spin_unlock(&clp->cl_lock);
 300         return delegation;
 301 }
 302
 303 static struct nfs_delegation *
 304 nfs_inode_detach_delegation(struct inode *inode)
 305 {
 306         struct nfs_inode *nfsi = NFS_I(inode);
 307         struct nfs_server *server = NFS_SERVER(inode);
 308         struct nfs_delegation *delegation;
 309
 310         delegation = nfs_start_delegation_return(nfsi);
 311         if (delegation == NULL)
 312                 return NULL;
 313         return nfs_detach_delegation(nfsi, delegation, server);
 314 }
 315
 316 static void
 317 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 318                 const struct nfs_delegation *update)
 319 {
 320         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 321                 delegation->stateid.seqid = update->stateid.seqid;
 322                 smp_wmb();
 323                 delegation->type = update->type;
 324         }
 325 }
 326
 327 /**
 328  * nfs_inode_set_delegation - set up a delegation on an inode
 329  * @inode: inode to which delegation applies
 330  * @cred: cred to use for subsequent delegation processing
 331  * @res: new delegation state from server
 332  *
 333  * Returns zero on success, or a negative errno value.
 334  */
 335 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 336 {
 337         struct nfs_server *server = NFS_SERVER(inode);
 338         struct nfs_client *clp = server->nfs_client;
 339         struct nfs_inode *nfsi = NFS_I(inode);
 340         struct nfs_delegation *delegation, *old_delegation;
 341         struct nfs_delegation *freeme = NULL;
 342         int status = 0;
 343
 344         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 345         if (delegation == NULL)
 346                 return -ENOMEM;
 347         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 348         delegation->type = res->delegation_type;
 349         delegation->pagemod_limit = res->pagemod_limit;
 350         delegation->change_attr = inode->i_version;
 351         delegation->cred = get_rpccred(cred);
 352         delegation->inode = inode;
 353         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 354         spin_lock_init(&delegation->lock);
 355
 356         spin_lock(&clp->cl_lock);
 357         old_delegation = rcu_dereference_protected(nfsi->delegation,
 358                                         lockdep_is_held(&clp->cl_lock));
 359         if (old_delegation != NULL) {
 360                 /* Is this an update of the existing delegation? */
 361                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 362                                         &delegation->stateid)) {
 363                         nfs_update_inplace_delegation(old_delegation,
 364                                         delegation);
 365                         goto out;
 366                 }
 367                 /*
 368                  * Deal with broken servers that hand out two
 369                  * delegations for the same file.
 370                  * Allow for upgrades to a WRITE delegation, but
 371                  * nothing else.
 372                  */
 373                 dfprintk(FILE, "%s: server %s handed out "
 374                                 "a duplicate delegation!\n",
 375                                 __func__, clp->cl_hostname);
 376                 if (delegation->type == old_delegation->type ||
 377                     !(delegation->type & FMODE_WRITE)) {
 378                         freeme = delegation;
 379                         delegation = NULL;
 380                         goto out;
 381                 }
 382                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 383                                         &old_delegation->flags))
 384                         goto out;
 385                 freeme = nfs_detach_delegation_locked(nfsi,
 386                                 old_delegation, clp);
 387                 if (freeme == NULL)
 388                         goto out;
 389         }
 390         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 391         rcu_assign_pointer(nfsi->delegation, delegation);
 392         delegation = NULL;
 393
 394         /* Ensure we revalidate the attributes and page cache! */
 395         spin_lock(&inode->i_lock);
 396         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 397         spin_unlock(&inode->i_lock);
 398         trace_nfs4_set_delegation(inode, res->delegation_type);
 399
 400 out:
 401         spin_unlock(&clp->cl_lock);
 402         if (delegation != NULL)
 403                 nfs_free_delegation(delegation);
 404         if (freeme != NULL)
 405                 nfs_do_return_delegation(inode, freeme, 0);
 406         return status;
 407 }
 408
 409 /*
 410  * Basic procedure for returning a delegation to the server
 411  */
 412 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 413 {
 414         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 415         struct nfs_inode *nfsi = NFS_I(inode);
 416         int err = 0;
 417
 418         if (delegation == NULL)
 419                 return 0;
 420         do {
 421                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 422                         break;
 423                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 424                                 delegation->type);
 425                 if (!issync || err != -EAGAIN)
 426                         break;
 427                 /*
 428                  * Guard against state recovery
 429                  */
 430                 err = nfs4_wait_clnt_recover(clp);
 431         } while (err == 0);
 432
 433         if (err) {
 434                 nfs_abort_delegation_return(delegation, clp);
 435                 goto out;
 436         }
 437         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 438                 goto out;
 439
 440         err = nfs_do_return_delegation(inode, delegation, issync);
 441 out:
 442         return err;
 443 }
 444
 445 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 446 {
 447         bool ret = false;
 448
 449         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 450                 goto out;
 451         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 452                 ret = true;
 453         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 454                 struct inode *inode;
 455
 456                 spin_lock(&delegation->lock);
 457                 inode = delegation->inode;
 458                 if (inode && list_empty(&NFS_I(inode)->open_files))
 459                         ret = true;
 460                 spin_unlock(&delegation->lock);
 461         }
 462 out:
 463         return ret;
 464 }
 465
 466 /**
 467  * nfs_client_return_marked_delegations - return previously marked delegations
 468  * @clp: nfs_client to process
 469  *
 470  * Note that this function is designed to be called by the state
 471  * manager thread. For this reason, it cannot flush the dirty data,
 472  * since that could deadlock in case of a state recovery error.
 473  *
 474  * Returns zero on success, or a negative errno value.
 475  */
 476 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 477 {
 478         struct nfs_delegation *delegation;
 479         struct nfs_server *server;
 480         struct inode *inode;
 481         int err = 0;
 482
 483 restart:
 484         rcu_read_lock();
 485         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 486                 list_for_each_entry_rcu(delegation, &server->delegations,
 487                                                                 super_list) {
 488                         if (!nfs_delegation_need_return(delegation))
 489                                 continue;
 490                         if (!nfs_sb_active(server->super))
 491                                 continue;
 492                         inode = nfs_delegation_grab_inode(delegation);
 493                         if (inode == NULL) {
 494                                 rcu_read_unlock();
 495                                 nfs_sb_deactive(server->super);
 496                                 goto restart;
 497                         }
 498                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 499                         rcu_read_unlock();
 500
 501                         err = nfs_end_delegation_return(inode, delegation, 0);
 502                         iput(inode);
 503                         nfs_sb_deactive(server->super);
 504                         if (!err)
 505                                 goto restart;
 506                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 507                         return err;
 508                 }
 509         }
 510         rcu_read_unlock();
 511         return 0;
 512 }
 513
 514 /**
 515  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 516  * @inode: inode to process
 517  *
 518  * Does not protect against delegation reclaims, therefore really only safe
 519  * to be called from nfs4_clear_inode().
 520  */
 521 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 522 {
 523         struct nfs_delegation *delegation;
 524
 525         delegation = nfs_inode_detach_delegation(inode);
 526         if (delegation != NULL)
 527                 nfs_do_return_delegation(inode, delegation, 1);
 528 }
 529
 530 /**
 531  * nfs_inode_return_delegation - synchronously return a delegation
 532  * @inode: inode to process
 533  *
 534  * This routine will always flush any dirty data to disk on the
 535  * assumption that if we need to return the delegation, then
 536  * we should stop caching.
 537  *
 538  * Returns zero on success, or a negative errno value.
 539  */
 540 int nfs4_inode_return_delegation(struct inode *inode)
 541 {
 542         struct nfs_inode *nfsi = NFS_I(inode);
 543         struct nfs_delegation *delegation;
 544         int err = 0;
 545
 546         nfs_wb_all(inode);
 547         delegation = nfs_start_delegation_return(nfsi);
 548         if (delegation != NULL)
 549                 err = nfs_end_delegation_return(inode, delegation, 1);
 550         return err;
 551 }
 552
 553 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 554                 struct nfs_delegation *delegation)
 555 {
 556         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 557         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 558 }
 559
 560 static void nfs_mark_return_delegation(struct nfs_server *server,
 561                 struct nfs_delegation *delegation)
 562 {
 563         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 564         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 565 }
 566
 567 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 568 {
 569         struct nfs_delegation *delegation;
 570         bool ret = false;
 571
 572         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 573                 nfs_mark_return_delegation(server, delegation);
 574                 ret = true;
 575         }
 576         return ret;
 577 }
 578
 579 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 580 {
 581         struct nfs_server *server;
 582
 583         rcu_read_lock();
 584         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 585                 nfs_server_mark_return_all_delegations(server);
 586         rcu_read_unlock();
 587 }
 588
 589 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 590 {
 591         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 592                 nfs4_schedule_state_manager(clp);
 593 }
 594
 595 /**
 596  * nfs_expire_all_delegations
 597  * @clp: client to process
 598  *
 599  */
 600 void nfs_expire_all_delegations(struct nfs_client *clp)
 601 {
 602         nfs_client_mark_return_all_delegations(clp);
 603         nfs_delegation_run_state_manager(clp);
 604 }
 605
 606 /**
 607  * nfs_super_return_all_delegations - return delegations for one superblock
 608  * @sb: sb to process
 609  *
 610  */
 611 void nfs_server_return_all_delegations(struct nfs_server *server)
 612 {
 613         struct nfs_client *clp = server->nfs_client;
 614         bool need_wait;
 615
 616         if (clp == NULL)
 617                 return;
 618
 619         rcu_read_lock();
 620         need_wait = nfs_server_mark_return_all_delegations(server);
 621         rcu_read_unlock();
 622
 623         if (need_wait) {
 624                 nfs4_schedule_state_manager(clp);
 625                 nfs4_wait_clnt_recover(clp);
 626         }
 627 }
 628
 629 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 630                                                  fmode_t flags)
 631 {
 632         struct nfs_delegation *delegation;
 633
 634         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 635                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 636                         continue;
 637                 if (delegation->type & flags)
 638                         nfs_mark_return_if_closed_delegation(server, delegation);
 639         }
 640 }
 641
 642 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 643                                                         fmode_t flags)
 644 {
 645         struct nfs_server *server;
 646
 647         rcu_read_lock();
 648         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 649                 nfs_mark_return_unused_delegation_types(server, flags);
 650         rcu_read_unlock();
 651 }
 652
 653 static void nfs_mark_delegation_revoked(struct nfs_server *server,
 654                 struct nfs_delegation *delegation)
 655 {
 656         set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 657         delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
 658         nfs_mark_return_delegation(server, delegation);
 659 }
 660
 661 static bool nfs_revoke_delegation(struct inode *inode,
 662                 const nfs4_stateid *stateid)
 663 {
 664         struct nfs_delegation *delegation;
 665         nfs4_stateid tmp;
 666         bool ret = false;
 667
 668         rcu_read_lock();
 669         delegation = rcu_dereference(NFS_I(inode)->delegation);
 670         if (delegation == NULL)
 671                 goto out;
 672         if (stateid == NULL) {
 673                 nfs4_stateid_copy(&tmp, &delegation->stateid);
 674                 stateid = &tmp;
 675         } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
 676                 goto out;
 677         nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
 678         ret = true;
 679 out:
 680         rcu_read_unlock();
 681         if (ret)
 682                 nfs_inode_find_state_and_recover(inode, stateid);
 683         return ret;
 684 }
 685
 686 void nfs_remove_bad_delegation(struct inode *inode,
 687                 const nfs4_stateid *stateid)
 688 {
 689         struct nfs_delegation *delegation;
 690
 691         if (!nfs_revoke_delegation(inode, stateid))
 692                 return;
 693         delegation = nfs_inode_detach_delegation(inode);
 694         if (delegation)
 695                 nfs_free_delegation(delegation);
 696 }
 697 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 698
 699 /**
 700  * nfs_expire_unused_delegation_types
 701  * @clp: client to process
 702  * @flags: delegation types to expire
 703  *
 704  */
 705 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 706 {
 707         nfs_client_mark_return_unused_delegation_types(clp, flags);
 708         nfs_delegation_run_state_manager(clp);
 709 }
 710
 711 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 712 {
 713         struct nfs_delegation *delegation;
 714
 715         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 716                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 717                         continue;
 718                 nfs_mark_return_if_closed_delegation(server, delegation);
 719         }
 720 }
 721
 722 /**
 723  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 724  * @clp: nfs_client to process
 725  *
 726  */
 727 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 728 {
 729         struct nfs_server *server;
 730
 731         rcu_read_lock();
 732         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 733                 nfs_mark_return_unreferenced_delegations(server);
 734         rcu_read_unlock();
 735
 736         nfs_delegation_run_state_manager(clp);
 737 }
 738
 739 /**
 740  * nfs_async_inode_return_delegation - asynchronously return a delegation
 741  * @inode: inode to process
 742  * @stateid: state ID information
 743  *
 744  * Returns zero on success, or a negative errno value.
 745  */
 746 int nfs_async_inode_return_delegation(struct inode *inode,
 747                                       const nfs4_stateid *stateid)
 748 {
 749         struct nfs_server *server = NFS_SERVER(inode);
 750         struct nfs_client *clp = server->nfs_client;
 751         struct nfs_delegation *delegation;
 752
 753         rcu_read_lock();
 754         delegation = rcu_dereference(NFS_I(inode)->delegation);
 755         if (delegation == NULL)
 756                 goto out_enoent;
 757         if (stateid != NULL &&
 758             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 759                 goto out_enoent;
 760         nfs_mark_return_delegation(server, delegation);
 761         rcu_read_unlock();
 762
 763         nfs_delegation_run_state_manager(clp);
 764         return 0;
 765 out_enoent:
 766         rcu_read_unlock();
 767         return -ENOENT;
 768 }
 769
 770 static struct inode *
 771 nfs_delegation_find_inode_server(struct nfs_server *server,
 772                                  const struct nfs_fh *fhandle)
 773 {
 774         struct nfs_delegation *delegation;
 775         struct inode *res = NULL;
 776
 777         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 778                 spin_lock(&delegation->lock);
 779                 if (delegation->inode != NULL &&
 780                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 781                         res = igrab(delegation->inode);
 782                 }
 783                 spin_unlock(&delegation->lock);
 784                 if (res != NULL)
 785                         break;
 786         }
 787         return res;
 788 }
 789
 790 /**
 791  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 792  * @clp: client state handle
 793  * @fhandle: filehandle from a delegation recall
 794  *
 795  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 796  * cannot be found.
 797  */
 798 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 799                                         const struct nfs_fh *fhandle)
 800 {
 801         struct nfs_server *server;
 802         struct inode *res = NULL;
 803
 804         rcu_read_lock();
 805         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 806                 res = nfs_delegation_find_inode_server(server, fhandle);
 807                 if (res != NULL)
 808                         break;
 809         }
 810         rcu_read_unlock();
 811         return res;
 812 }
 813
 814 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 815 {
 816         struct nfs_delegation *delegation;
 817
 818         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 819                 /*
 820                  * If the delegation may have been admin revoked, then we
 821                  * cannot reclaim it.
 822                  */
 823                 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
 824                         continue;
 825                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 826         }
 827 }
 828
 829 /**
 830  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 831  * @clp: nfs_client to process
 832  *
 833  */
 834 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 835 {
 836         struct nfs_server *server;
 837
 838         rcu_read_lock();
 839         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 840                 nfs_delegation_mark_reclaim_server(server);
 841         rcu_read_unlock();
 842 }
 843
 844 /**
 845  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 846  * @clp: nfs_client to process
 847  *
 848  */
 849 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 850 {
 851         struct nfs_delegation *delegation;
 852         struct nfs_server *server;
 853         struct inode *inode;
 854
 855 restart:
 856         rcu_read_lock();
 857         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 858                 list_for_each_entry_rcu(delegation, &server->delegations,
 859                                                                 super_list) {
 860                         if (test_bit(NFS_DELEGATION_RETURNING,
 861                                                 &delegation->flags))
 862                                 continue;
 863                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 864                                                 &delegation->flags) == 0)
 865                                 continue;
 866                         if (!nfs_sb_active(server->super))
 867                                 continue;
 868                         inode = nfs_delegation_grab_inode(delegation);
 869                         if (inode == NULL) {
 870                                 rcu_read_unlock();
 871                                 nfs_sb_deactive(server->super);
 872                                 goto restart;
 873                         }
 874                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 875                         rcu_read_unlock();
 876                         if (delegation != NULL) {
 877                                 delegation = nfs_detach_delegation(NFS_I(inode),
 878                                         delegation, server);
 879                                 if (delegation != NULL)
 880                                         nfs_free_delegation(delegation);
 881                         }
 882                         iput(inode);
 883                         nfs_sb_deactive(server->super);
 884                         goto restart;
 885                 }
 886         }
 887         rcu_read_unlock();
 888 }
 889
 890 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
 891 {
 892         return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
 893                                 BIT(NFS4CLNT_LEASE_EXPIRED) |
 894                                 BIT(NFS4CLNT_SESSION_RESET))) != 0;
 895 }
 896
 897 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
 898             struct nfs_delegation *delegation)
 899 {
 900         if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
 901                 return;
 902         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 903         set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 904         set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
 905 }
 906
 907 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
 908                 struct inode *inode)
 909 {
 910         struct nfs_delegation *delegation;
 911
 912         rcu_read_lock();
 913         delegation = rcu_dereference(NFS_I(inode)->delegation);
 914         if (delegation)
 915                 nfs_mark_test_expired_delegation(server, delegation);
 916         rcu_read_unlock();
 917
 918 }
 919
 920 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
 921 {
 922         struct nfs_delegation *delegation;
 923
 924         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
 925                 nfs_mark_test_expired_delegation(server, delegation);
 926 }
 927
 928 /**
 929  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
 930  * @clp: nfs_client to process
 931  *
 932  * Iterates through all the delegations associated with this server and
 933  * marks them as needing to be checked for validity.
 934  */
 935 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
 936 {
 937         struct nfs_server *server;
 938
 939         rcu_read_lock();
 940         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 941                 nfs_delegation_mark_test_expired_server(server);
 942         rcu_read_unlock();
 943 }
 944
 945 /**
 946  * nfs_reap_expired_delegations - reap expired delegations
 947  * @clp: nfs_client to process
 948  *
 949  * Iterates through all the delegations associated with this server and
 950  * checks if they have may have been revoked. This function is usually
 951  * expected to be called in cases where the server may have lost its
 952  * lease.
 953  */
 954 void nfs_reap_expired_delegations(struct nfs_client *clp)
 955 {
 956         const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
 957         struct nfs_delegation *delegation;
 958         struct nfs_server *server;
 959         struct inode *inode;
 960         struct rpc_cred *cred;
 961         nfs4_stateid stateid;
 962
 963 restart:
 964         rcu_read_lock();
 965         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 966                 list_for_each_entry_rcu(delegation, &server->delegations,
 967                                                                 super_list) {
 968                         if (test_bit(NFS_DELEGATION_RETURNING,
 969                                                 &delegation->flags))
 970                                 continue;
 971                         if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
 972                                                 &delegation->flags) == 0)
 973                                 continue;
 974                         if (!nfs_sb_active(server->super))
 975                                 continue;
 976                         inode = nfs_delegation_grab_inode(delegation);
 977                         if (inode == NULL) {
 978                                 rcu_read_unlock();
 979                                 nfs_sb_deactive(server->super);
 980                                 goto restart;
 981                         }
 982                         cred = get_rpccred_rcu(delegation->cred);
 983                         nfs4_stateid_copy(&stateid, &delegation->stateid);
 984                         clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 985                         rcu_read_unlock();
 986                         if (cred != NULL &&
 987                             ops->test_and_free_expired(server, &stateid, cred) < 0) {
 988                                 nfs_revoke_delegation(inode, &stateid);
 989                                 nfs_inode_find_state_and_recover(inode, &stateid);
 990                         }
 991                         put_rpccred(cred);
 992                         if (nfs4_server_rebooted(clp)) {
 993                                 nfs_inode_mark_test_expired_delegation(server,inode);
 994                                 iput(inode);
 995                                 nfs_sb_deactive(server->super);
 996                                 return;
 997                         }
 998                         iput(inode);
 999                         nfs_sb_deactive(server->super);
1000                         goto restart;
1001                 }
1002         }
1003         rcu_read_unlock();
1004 }
1005
1006 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1007                 const nfs4_stateid *stateid)
1008 {
1009         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1010         struct nfs_delegation *delegation;
1011         bool found = false;
1012
1013         rcu_read_lock();
1014         delegation = rcu_dereference(NFS_I(inode)->delegation);
1015         if (delegation &&
1016             nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1017                 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1018                 found = true;
1019         }
1020         rcu_read_unlock();
1021         if (found)
1022                 nfs4_schedule_state_manager(clp);
1023 }
1024
1025 /**
1026  * nfs_delegations_present - check for existence of delegations
1027  * @clp: client state handle
1028  *
1029  * Returns one if there are any nfs_delegation structures attached
1030  * to this nfs_client.
1031  */
1032 int nfs_delegations_present(struct nfs_client *clp)
1033 {
1034         struct nfs_server *server;
1035         int ret = 0;
1036
1037         rcu_read_lock();
1038         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1039                 if (!list_empty(&server->delegations)) {
1040                         ret = 1;
1041                         break;
1042                 }
1043         rcu_read_unlock();
1044         return ret;
1045 }
1046
1047 /**
1048  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1049  * @inode: inode to check
1050  * @flags: delegation type requirement
1051  * @dst: stateid data structure to fill in
1052  * @cred: optional argument to retrieve credential
1053  *
1054  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1055  * otherwise "false" is returned.
1056  */
1057 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1058                 nfs4_stateid *dst, struct rpc_cred **cred)
1059 {
1060         struct nfs_inode *nfsi = NFS_I(inode);
1061         struct nfs_delegation *delegation;
1062         bool ret;
1063
1064         flags &= FMODE_READ|FMODE_WRITE;
1065         rcu_read_lock();
1066         delegation = rcu_dereference(nfsi->delegation);
1067         ret = nfs4_is_valid_delegation(delegation, flags);
1068         if (ret) {
1069                 nfs4_stateid_copy(dst, &delegation->stateid);
1070                 nfs_mark_delegation_referenced(delegation);
1071                 if (cred)
1072                         *cred = get_rpccred(delegation->cred);
1073         }
1074         rcu_read_unlock();
1075         return ret;
1076 }
1077
1078 /**
1079  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1080  * @inode: inode to check
1081  *
1082  * This function checks the number of outstanding writes to the file
1083  * against the delegation 'space_limit' field to see if
1084  * the spec requires us to flush the file on close.
1085  */
1086 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1087 {
1088         struct nfs_inode *nfsi = NFS_I(inode);
1089         struct nfs_delegation *delegation;
1090         bool ret = true;
1091
1092         rcu_read_lock();
1093         delegation = rcu_dereference(nfsi->delegation);
1094         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1095                 goto out;
1096         if (nfsi->nrequests < delegation->pagemod_limit)
1097                 ret = false;
1098 out:
1099         rcu_read_unlock();
1100         return ret;
1101 }