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 int
  45 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  46 {
  47         struct nfs_delegation *delegation;
  48         int ret = 0;
  49
  50         flags &= FMODE_READ|FMODE_WRITE;
  51         rcu_read_lock();
  52         delegation = rcu_dereference(NFS_I(inode)->delegation);
  53         if (delegation != NULL && (delegation->type & flags) == flags &&
  54             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
  55                 if (mark)
  56                         nfs_mark_delegation_referenced(delegation);
  57                 ret = 1;
  58         }
  59         rcu_read_unlock();
  60         return ret;
  61 }
  62 /**
  63  * nfs_have_delegation - check if inode has a delegation, mark it
  64  * NFS_DELEGATION_REFERENCED if there is one.
  65  * @inode: inode to check
  66  * @flags: delegation types to check for
  67  *
  68  * Returns one if inode has the indicated delegation, otherwise zero.
  69  */
  70 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  71 {
  72         return nfs4_do_check_delegation(inode, flags, true);
  73 }
  74
  75 /*
  76  * nfs4_check_delegation - check if inode has a delegation, do not mark
  77  * NFS_DELEGATION_REFERENCED if it has one.
  78  */
  79 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
  80 {
  81         return nfs4_do_check_delegation(inode, flags, false);
  82 }
  83
  84 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
  85 {
  86         struct inode *inode = state->inode;
  87         struct file_lock *fl;
  88         struct file_lock_context *flctx = inode->i_flctx;
  89         struct list_head *list;
  90         int status = 0;
  91
  92         if (flctx == NULL)
  93                 goto out;
  94
  95         list = &flctx->flc_posix;
  96         spin_lock(&flctx->flc_lock);
  97 restart:
  98         list_for_each_entry(fl, list, fl_list) {
  99                 if (nfs_file_open_context(fl->fl_file) != ctx)
 100                         continue;
 101                 spin_unlock(&flctx->flc_lock);
 102                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 103                 if (status < 0)
 104                         goto out;
 105                 spin_lock(&flctx->flc_lock);
 106         }
 107         if (list == &flctx->flc_posix) {
 108                 list = &flctx->flc_flock;
 109                 goto restart;
 110         }
 111         spin_unlock(&flctx->flc_lock);
 112 out:
 113         return status;
 114 }
 115
 116 static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
 117 {
 118         struct nfs_inode *nfsi = NFS_I(inode);
 119         struct nfs_open_context *ctx;
 120         struct nfs4_state_owner *sp;
 121         struct nfs4_state *state;
 122         unsigned int seq;
 123         int err;
 124
 125 again:
 126         spin_lock(&inode->i_lock);
 127         list_for_each_entry(ctx, &nfsi->open_files, list) {
 128                 state = ctx->state;
 129                 if (state == NULL)
 130                         continue;
 131                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 132                         continue;
 133                 if (!nfs4_valid_open_stateid(state))
 134                         continue;
 135                 if (!nfs4_stateid_match(&state->stateid, stateid))
 136                         continue;
 137                 get_nfs_open_context(ctx);
 138                 spin_unlock(&inode->i_lock);
 139                 sp = state->owner;
 140                 /* Block nfs4_proc_unlck */
 141                 mutex_lock(&sp->so_delegreturn_mutex);
 142                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 143                 err = nfs4_open_delegation_recall(ctx, state, stateid);
 144                 if (!err)
 145                         err = nfs_delegation_claim_locks(ctx, state, stateid);
 146                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 147                         err = -EAGAIN;
 148                 mutex_unlock(&sp->so_delegreturn_mutex);
 149                 put_nfs_open_context(ctx);
 150                 if (err != 0)
 151                         return err;
 152                 goto again;
 153         }
 154         spin_unlock(&inode->i_lock);
 155         return 0;
 156 }
 157
 158 /**
 159  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 160  * @inode: inode to process
 161  * @cred: credential to use for request
 162  * @res: new delegation state from server
 163  *
 164  */
 165 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
 166                                   struct nfs_openres *res)
 167 {
 168         struct nfs_delegation *delegation;
 169         struct rpc_cred *oldcred = NULL;
 170
 171         rcu_read_lock();
 172         delegation = rcu_dereference(NFS_I(inode)->delegation);
 173         if (delegation != NULL) {
 174                 spin_lock(&delegation->lock);
 175                 if (delegation->inode != NULL) {
 176                         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 177                         delegation->type = res->delegation_type;
 178                         delegation->maxsize = res->maxsize;
 179                         oldcred = delegation->cred;
 180                         delegation->cred = get_rpccred(cred);
 181                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 182                                   &delegation->flags);
 183                         NFS_I(inode)->delegation_state = delegation->type;
 184                         spin_unlock(&delegation->lock);
 185                         put_rpccred(oldcred);
 186                         rcu_read_unlock();
 187                         trace_nfs4_reclaim_delegation(inode, res->delegation_type);
 188                 } else {
 189                         /* We appear to have raced with a delegation return. */
 190                         spin_unlock(&delegation->lock);
 191                         rcu_read_unlock();
 192                         nfs_inode_set_delegation(inode, cred, res);
 193                 }
 194         } else {
 195                 rcu_read_unlock();
 196         }
 197 }
 198
 199 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 200 {
 201         int res = 0;
 202
 203         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 204                 res = nfs4_proc_delegreturn(inode,
 205                                 delegation->cred,
 206                                 &delegation->stateid,
 207                                 issync);
 208         nfs_free_delegation(delegation);
 209         return res;
 210 }
 211
 212 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 213 {
 214         struct inode *inode = NULL;
 215
 216         spin_lock(&delegation->lock);
 217         if (delegation->inode != NULL)
 218                 inode = igrab(delegation->inode);
 219         spin_unlock(&delegation->lock);
 220         return inode;
 221 }
 222
 223 static struct nfs_delegation *
 224 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 225 {
 226         struct nfs_delegation *ret = NULL;
 227         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 228
 229         if (delegation == NULL)
 230                 goto out;
 231         spin_lock(&delegation->lock);
 232         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 233                 ret = delegation;
 234         spin_unlock(&delegation->lock);
 235 out:
 236         return ret;
 237 }
 238
 239 static struct nfs_delegation *
 240 nfs_start_delegation_return(struct nfs_inode *nfsi)
 241 {
 242         struct nfs_delegation *delegation;
 243
 244         rcu_read_lock();
 245         delegation = nfs_start_delegation_return_locked(nfsi);
 246         rcu_read_unlock();
 247         return delegation;
 248 }
 249
 250 static void
 251 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 252                 struct nfs_client *clp)
 253 {
 254
 255         spin_lock(&delegation->lock);
 256         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 257         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 258         spin_unlock(&delegation->lock);
 259         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 260 }
 261
 262 static struct nfs_delegation *
 263 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 264                 struct nfs_delegation *delegation,
 265                 struct nfs_client *clp)
 266 {
 267         struct nfs_delegation *deleg_cur =
 268                 rcu_dereference_protected(nfsi->delegation,
 269                                 lockdep_is_held(&clp->cl_lock));
 270
 271         if (deleg_cur == NULL || delegation != deleg_cur)
 272                 return NULL;
 273
 274         spin_lock(&delegation->lock);
 275         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 276         list_del_rcu(&delegation->super_list);
 277         delegation->inode = NULL;
 278         nfsi->delegation_state = 0;
 279         rcu_assign_pointer(nfsi->delegation, NULL);
 280         spin_unlock(&delegation->lock);
 281         return delegation;
 282 }
 283
 284 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 285                 struct nfs_delegation *delegation,
 286                 struct nfs_server *server)
 287 {
 288         struct nfs_client *clp = server->nfs_client;
 289
 290         spin_lock(&clp->cl_lock);
 291         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 292         spin_unlock(&clp->cl_lock);
 293         return delegation;
 294 }
 295
 296 static struct nfs_delegation *
 297 nfs_inode_detach_delegation(struct inode *inode)
 298 {
 299         struct nfs_inode *nfsi = NFS_I(inode);
 300         struct nfs_server *server = NFS_SERVER(inode);
 301         struct nfs_delegation *delegation;
 302
 303         delegation = nfs_start_delegation_return(nfsi);
 304         if (delegation == NULL)
 305                 return NULL;
 306         return nfs_detach_delegation(nfsi, delegation, server);
 307 }
 308
 309 static void
 310 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 311                 const struct nfs_delegation *update)
 312 {
 313         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 314                 delegation->stateid.seqid = update->stateid.seqid;
 315                 smp_wmb();
 316                 delegation->type = update->type;
 317         }
 318 }
 319
 320 /**
 321  * nfs_inode_set_delegation - set up a delegation on an inode
 322  * @inode: inode to which delegation applies
 323  * @cred: cred to use for subsequent delegation processing
 324  * @res: new delegation state from server
 325  *
 326  * Returns zero on success, or a negative errno value.
 327  */
 328 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 329 {
 330         struct nfs_server *server = NFS_SERVER(inode);
 331         struct nfs_client *clp = server->nfs_client;
 332         struct nfs_inode *nfsi = NFS_I(inode);
 333         struct nfs_delegation *delegation, *old_delegation;
 334         struct nfs_delegation *freeme = NULL;
 335         int status = 0;
 336
 337         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 338         if (delegation == NULL)
 339                 return -ENOMEM;
 340         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 341         delegation->type = res->delegation_type;
 342         delegation->maxsize = res->maxsize;
 343         delegation->change_attr = inode->i_version;
 344         delegation->cred = get_rpccred(cred);
 345         delegation->inode = inode;
 346         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 347         spin_lock_init(&delegation->lock);
 348
 349         spin_lock(&clp->cl_lock);
 350         old_delegation = rcu_dereference_protected(nfsi->delegation,
 351                                         lockdep_is_held(&clp->cl_lock));
 352         if (old_delegation != NULL) {
 353                 /* Is this an update of the existing delegation? */
 354                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 355                                         &delegation->stateid)) {
 356                         nfs_update_inplace_delegation(old_delegation,
 357                                         delegation);
 358                         nfsi->delegation_state = old_delegation->type;
 359                         goto out;
 360                 }
 361                 /*
 362                  * Deal with broken servers that hand out two
 363                  * delegations for the same file.
 364                  * Allow for upgrades to a WRITE delegation, but
 365                  * nothing else.
 366                  */
 367                 dfprintk(FILE, "%s: server %s handed out "
 368                                 "a duplicate delegation!\n",
 369                                 __func__, clp->cl_hostname);
 370                 if (delegation->type == old_delegation->type ||
 371                     !(delegation->type & FMODE_WRITE)) {
 372                         freeme = delegation;
 373                         delegation = NULL;
 374                         goto out;
 375                 }
 376                 freeme = nfs_detach_delegation_locked(nfsi,
 377                                 old_delegation, clp);
 378                 if (freeme == NULL)
 379                         goto out;
 380         }
 381         list_add_rcu(&delegation->super_list, &server->delegations);
 382         nfsi->delegation_state = delegation->type;
 383         rcu_assign_pointer(nfsi->delegation, delegation);
 384         delegation = NULL;
 385
 386         /* Ensure we revalidate the attributes and page cache! */
 387         spin_lock(&inode->i_lock);
 388         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 389         spin_unlock(&inode->i_lock);
 390         trace_nfs4_set_delegation(inode, res->delegation_type);
 391
 392 out:
 393         spin_unlock(&clp->cl_lock);
 394         if (delegation != NULL)
 395                 nfs_free_delegation(delegation);
 396         if (freeme != NULL)
 397                 nfs_do_return_delegation(inode, freeme, 0);
 398         return status;
 399 }
 400
 401 /*
 402  * Basic procedure for returning a delegation to the server
 403  */
 404 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 405 {
 406         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 407         struct nfs_inode *nfsi = NFS_I(inode);
 408         int err = 0;
 409
 410         if (delegation == NULL)
 411                 return 0;
 412         do {
 413                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 414                         break;
 415                 err = nfs_delegation_claim_opens(inode, &delegation->stateid);
 416                 if (!issync || err != -EAGAIN)
 417                         break;
 418                 /*
 419                  * Guard against state recovery
 420                  */
 421                 err = nfs4_wait_clnt_recover(clp);
 422         } while (err == 0);
 423
 424         if (err) {
 425                 nfs_abort_delegation_return(delegation, clp);
 426                 goto out;
 427         }
 428         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 429                 goto out;
 430
 431         err = nfs_do_return_delegation(inode, delegation, issync);
 432 out:
 433         return err;
 434 }
 435
 436 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 437 {
 438         bool ret = false;
 439
 440         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 441                 ret = true;
 442         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 443                 struct inode *inode;
 444
 445                 spin_lock(&delegation->lock);
 446                 inode = delegation->inode;
 447                 if (inode && list_empty(&NFS_I(inode)->open_files))
 448                         ret = true;
 449                 spin_unlock(&delegation->lock);
 450         }
 451         return ret;
 452 }
 453
 454 /**
 455  * nfs_client_return_marked_delegations - return previously marked delegations
 456  * @clp: nfs_client to process
 457  *
 458  * Note that this function is designed to be called by the state
 459  * manager thread. For this reason, it cannot flush the dirty data,
 460  * since that could deadlock in case of a state recovery error.
 461  *
 462  * Returns zero on success, or a negative errno value.
 463  */
 464 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 465 {
 466         struct nfs_delegation *delegation;
 467         struct nfs_server *server;
 468         struct inode *inode;
 469         int err = 0;
 470
 471 restart:
 472         rcu_read_lock();
 473         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 474                 list_for_each_entry_rcu(delegation, &server->delegations,
 475                                                                 super_list) {
 476                         if (!nfs_delegation_need_return(delegation))
 477                                 continue;
 478                         inode = nfs_delegation_grab_inode(delegation);
 479                         if (inode == NULL)
 480                                 continue;
 481                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 482                         rcu_read_unlock();
 483
 484                         err = nfs_end_delegation_return(inode, delegation, 0);
 485                         iput(inode);
 486                         if (!err)
 487                                 goto restart;
 488                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 489                         return err;
 490                 }
 491         }
 492         rcu_read_unlock();
 493         return 0;
 494 }
 495
 496 /**
 497  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 498  * @inode: inode to process
 499  *
 500  * Does not protect against delegation reclaims, therefore really only safe
 501  * to be called from nfs4_clear_inode().
 502  */
 503 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 504 {
 505         struct nfs_delegation *delegation;
 506
 507         delegation = nfs_inode_detach_delegation(inode);
 508         if (delegation != NULL)
 509                 nfs_do_return_delegation(inode, delegation, 0);
 510 }
 511
 512 /**
 513  * nfs_inode_return_delegation - synchronously return a delegation
 514  * @inode: inode to process
 515  *
 516  * This routine will always flush any dirty data to disk on the
 517  * assumption that if we need to return the delegation, then
 518  * we should stop caching.
 519  *
 520  * Returns zero on success, or a negative errno value.
 521  */
 522 int nfs4_inode_return_delegation(struct inode *inode)
 523 {
 524         struct nfs_inode *nfsi = NFS_I(inode);
 525         struct nfs_delegation *delegation;
 526         int err = 0;
 527
 528         nfs_wb_all(inode);
 529         delegation = nfs_start_delegation_return(nfsi);
 530         if (delegation != NULL)
 531                 err = nfs_end_delegation_return(inode, delegation, 1);
 532         return err;
 533 }
 534
 535 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 536                 struct nfs_delegation *delegation)
 537 {
 538         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 539         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 540 }
 541
 542 static void nfs_mark_return_delegation(struct nfs_server *server,
 543                 struct nfs_delegation *delegation)
 544 {
 545         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 546         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 547 }
 548
 549 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 550 {
 551         struct nfs_delegation *delegation;
 552         bool ret = false;
 553
 554         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 555                 nfs_mark_return_delegation(server, delegation);
 556                 ret = true;
 557         }
 558         return ret;
 559 }
 560
 561 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 562 {
 563         struct nfs_server *server;
 564
 565         rcu_read_lock();
 566         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 567                 nfs_server_mark_return_all_delegations(server);
 568         rcu_read_unlock();
 569 }
 570
 571 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 572 {
 573         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 574                 nfs4_schedule_state_manager(clp);
 575 }
 576
 577 /**
 578  * nfs_expire_all_delegations
 579  * @clp: client to process
 580  *
 581  */
 582 void nfs_expire_all_delegations(struct nfs_client *clp)
 583 {
 584         nfs_client_mark_return_all_delegations(clp);
 585         nfs_delegation_run_state_manager(clp);
 586 }
 587
 588 /**
 589  * nfs_super_return_all_delegations - return delegations for one superblock
 590  * @sb: sb to process
 591  *
 592  */
 593 void nfs_server_return_all_delegations(struct nfs_server *server)
 594 {
 595         struct nfs_client *clp = server->nfs_client;
 596         bool need_wait;
 597
 598         if (clp == NULL)
 599                 return;
 600
 601         rcu_read_lock();
 602         need_wait = nfs_server_mark_return_all_delegations(server);
 603         rcu_read_unlock();
 604
 605         if (need_wait) {
 606                 nfs4_schedule_state_manager(clp);
 607                 nfs4_wait_clnt_recover(clp);
 608         }
 609 }
 610
 611 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 612                                                  fmode_t flags)
 613 {
 614         struct nfs_delegation *delegation;
 615
 616         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 617                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 618                         continue;
 619                 if (delegation->type & flags)
 620                         nfs_mark_return_if_closed_delegation(server, delegation);
 621         }
 622 }
 623
 624 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 625                                                         fmode_t flags)
 626 {
 627         struct nfs_server *server;
 628
 629         rcu_read_lock();
 630         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 631                 nfs_mark_return_unused_delegation_types(server, flags);
 632         rcu_read_unlock();
 633 }
 634
 635 static void nfs_revoke_delegation(struct inode *inode)
 636 {
 637         struct nfs_delegation *delegation;
 638         rcu_read_lock();
 639         delegation = rcu_dereference(NFS_I(inode)->delegation);
 640         if (delegation != NULL) {
 641                 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 642                 nfs_mark_return_delegation(NFS_SERVER(inode), delegation);
 643         }
 644         rcu_read_unlock();
 645 }
 646
 647 void nfs_remove_bad_delegation(struct inode *inode)
 648 {
 649         struct nfs_delegation *delegation;
 650
 651         nfs_revoke_delegation(inode);
 652         delegation = nfs_inode_detach_delegation(inode);
 653         if (delegation) {
 654                 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
 655                 nfs_free_delegation(delegation);
 656         }
 657 }
 658 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 659
 660 /**
 661  * nfs_expire_unused_delegation_types
 662  * @clp: client to process
 663  * @flags: delegation types to expire
 664  *
 665  */
 666 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 667 {
 668         nfs_client_mark_return_unused_delegation_types(clp, flags);
 669         nfs_delegation_run_state_manager(clp);
 670 }
 671
 672 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 673 {
 674         struct nfs_delegation *delegation;
 675
 676         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 677                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 678                         continue;
 679                 nfs_mark_return_if_closed_delegation(server, delegation);
 680         }
 681 }
 682
 683 /**
 684  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 685  * @clp: nfs_client to process
 686  *
 687  */
 688 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 689 {
 690         struct nfs_server *server;
 691
 692         rcu_read_lock();
 693         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 694                 nfs_mark_return_unreferenced_delegations(server);
 695         rcu_read_unlock();
 696
 697         nfs_delegation_run_state_manager(clp);
 698 }
 699
 700 /**
 701  * nfs_async_inode_return_delegation - asynchronously return a delegation
 702  * @inode: inode to process
 703  * @stateid: state ID information
 704  *
 705  * Returns zero on success, or a negative errno value.
 706  */
 707 int nfs_async_inode_return_delegation(struct inode *inode,
 708                                       const nfs4_stateid *stateid)
 709 {
 710         struct nfs_server *server = NFS_SERVER(inode);
 711         struct nfs_client *clp = server->nfs_client;
 712         struct nfs_delegation *delegation;
 713
 714         filemap_flush(inode->i_mapping);
 715
 716         rcu_read_lock();
 717         delegation = rcu_dereference(NFS_I(inode)->delegation);
 718         if (delegation == NULL)
 719                 goto out_enoent;
 720
 721         if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 722                 goto out_enoent;
 723         nfs_mark_return_delegation(server, delegation);
 724         rcu_read_unlock();
 725
 726         nfs_delegation_run_state_manager(clp);
 727         return 0;
 728 out_enoent:
 729         rcu_read_unlock();
 730         return -ENOENT;
 731 }
 732
 733 static struct inode *
 734 nfs_delegation_find_inode_server(struct nfs_server *server,
 735                                  const struct nfs_fh *fhandle)
 736 {
 737         struct nfs_delegation *delegation;
 738         struct inode *res = NULL;
 739
 740         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 741                 spin_lock(&delegation->lock);
 742                 if (delegation->inode != NULL &&
 743                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 744                         res = igrab(delegation->inode);
 745                 }
 746                 spin_unlock(&delegation->lock);
 747                 if (res != NULL)
 748                         break;
 749         }
 750         return res;
 751 }
 752
 753 /**
 754  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 755  * @clp: client state handle
 756  * @fhandle: filehandle from a delegation recall
 757  *
 758  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 759  * cannot be found.
 760  */
 761 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 762                                         const struct nfs_fh *fhandle)
 763 {
 764         struct nfs_server *server;
 765         struct inode *res = NULL;
 766
 767         rcu_read_lock();
 768         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 769                 res = nfs_delegation_find_inode_server(server, fhandle);
 770                 if (res != NULL)
 771                         break;
 772         }
 773         rcu_read_unlock();
 774         return res;
 775 }
 776
 777 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 778 {
 779         struct nfs_delegation *delegation;
 780
 781         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
 782                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 783 }
 784
 785 /**
 786  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 787  * @clp: nfs_client to process
 788  *
 789  */
 790 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 791 {
 792         struct nfs_server *server;
 793
 794         rcu_read_lock();
 795         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 796                 nfs_delegation_mark_reclaim_server(server);
 797         rcu_read_unlock();
 798 }
 799
 800 /**
 801  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 802  * @clp: nfs_client to process
 803  *
 804  */
 805 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 806 {
 807         struct nfs_delegation *delegation;
 808         struct nfs_server *server;
 809         struct inode *inode;
 810
 811 restart:
 812         rcu_read_lock();
 813         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 814                 list_for_each_entry_rcu(delegation, &server->delegations,
 815                                                                 super_list) {
 816                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 817                                                 &delegation->flags) == 0)
 818                                 continue;
 819                         inode = nfs_delegation_grab_inode(delegation);
 820                         if (inode == NULL)
 821                                 continue;
 822                         delegation = nfs_detach_delegation(NFS_I(inode),
 823                                         delegation, server);
 824                         rcu_read_unlock();
 825
 826                         if (delegation != NULL)
 827                                 nfs_free_delegation(delegation);
 828                         iput(inode);
 829                         goto restart;
 830                 }
 831         }
 832         rcu_read_unlock();
 833 }
 834
 835 /**
 836  * nfs_delegations_present - check for existence of delegations
 837  * @clp: client state handle
 838  *
 839  * Returns one if there are any nfs_delegation structures attached
 840  * to this nfs_client.
 841  */
 842 int nfs_delegations_present(struct nfs_client *clp)
 843 {
 844         struct nfs_server *server;
 845         int ret = 0;
 846
 847         rcu_read_lock();
 848         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 849                 if (!list_empty(&server->delegations)) {
 850                         ret = 1;
 851                         break;
 852                 }
 853         rcu_read_unlock();
 854         return ret;
 855 }
 856
 857 /**
 858  * nfs4_copy_delegation_stateid - Copy inode's state ID information
 859  * @dst: stateid data structure to fill in
 860  * @inode: inode to check
 861  * @flags: delegation type requirement
 862  *
 863  * Returns "true" and fills in "dst->data" * if inode had a delegation,
 864  * otherwise "false" is returned.
 865  */
 866 bool nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode,
 867                 fmode_t flags)
 868 {
 869         struct nfs_inode *nfsi = NFS_I(inode);
 870         struct nfs_delegation *delegation;
 871         bool ret;
 872
 873         flags &= FMODE_READ|FMODE_WRITE;
 874         rcu_read_lock();
 875         delegation = rcu_dereference(nfsi->delegation);
 876         ret = (delegation != NULL && (delegation->type & flags) == flags);
 877         if (ret) {
 878                 nfs4_stateid_copy(dst, &delegation->stateid);
 879                 nfs_mark_delegation_referenced(delegation);
 880         }
 881         rcu_read_unlock();
 882         return ret;
 883 }