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,
 117                 const nfs4_stateid *stateid, fmode_t type)
 118 {
 119         struct nfs_inode *nfsi = NFS_I(inode);
 120         struct nfs_open_context *ctx;
 121         struct nfs4_state_owner *sp;
 122         struct nfs4_state *state;
 123         unsigned int seq;
 124         int err;
 125
 126 again:
 127         spin_lock(&inode->i_lock);
 128         list_for_each_entry(ctx, &nfsi->open_files, list) {
 129                 state = ctx->state;
 130                 if (state == NULL)
 131                         continue;
 132                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 133                         continue;
 134                 if (!nfs4_valid_open_stateid(state))
 135                         continue;
 136                 if (!nfs4_stateid_match(&state->stateid, stateid))
 137                         continue;
 138                 get_nfs_open_context(ctx);
 139                 spin_unlock(&inode->i_lock);
 140                 sp = state->owner;
 141                 /* Block nfs4_proc_unlck */
 142                 mutex_lock(&sp->so_delegreturn_mutex);
 143                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 144                 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
 145                 if (!err)
 146                         err = nfs_delegation_claim_locks(ctx, state, stateid);
 147                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 148                         err = -EAGAIN;
 149                 mutex_unlock(&sp->so_delegreturn_mutex);
 150                 put_nfs_open_context(ctx);
 151                 if (err != 0)
 152                         return err;
 153                 goto again;
 154         }
 155         spin_unlock(&inode->i_lock);
 156         return 0;
 157 }
 158
 159 /**
 160  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 161  * @inode: inode to process
 162  * @cred: credential to use for request
 163  * @res: new delegation state from server
 164  *
 165  */
 166 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
 167                                   struct nfs_openres *res)
 168 {
 169         struct nfs_delegation *delegation;
 170         struct rpc_cred *oldcred = NULL;
 171
 172         rcu_read_lock();
 173         delegation = rcu_dereference(NFS_I(inode)->delegation);
 174         if (delegation != NULL) {
 175                 spin_lock(&delegation->lock);
 176                 if (delegation->inode != NULL) {
 177                         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 178                         delegation->type = res->delegation_type;
 179                         delegation->pagemod_limit = res->pagemod_limit;
 180                         oldcred = delegation->cred;
 181                         delegation->cred = get_rpccred(cred);
 182                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 183                                   &delegation->flags);
 184                         spin_unlock(&delegation->lock);
 185                         rcu_read_unlock();
 186                         put_rpccred(oldcred);
 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         rcu_assign_pointer(nfsi->delegation, NULL);
 279         spin_unlock(&delegation->lock);
 280         return delegation;
 281 }
 282
 283 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 284                 struct nfs_delegation *delegation,
 285                 struct nfs_server *server)
 286 {
 287         struct nfs_client *clp = server->nfs_client;
 288
 289         spin_lock(&clp->cl_lock);
 290         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 291         spin_unlock(&clp->cl_lock);
 292         return delegation;
 293 }
 294
 295 static struct nfs_delegation *
 296 nfs_inode_detach_delegation(struct inode *inode)
 297 {
 298         struct nfs_inode *nfsi = NFS_I(inode);
 299         struct nfs_server *server = NFS_SERVER(inode);
 300         struct nfs_delegation *delegation;
 301
 302         delegation = nfs_start_delegation_return(nfsi);
 303         if (delegation == NULL)
 304                 return NULL;
 305         return nfs_detach_delegation(nfsi, delegation, server);
 306 }
 307
 308 static void
 309 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 310                 const struct nfs_delegation *update)
 311 {
 312         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 313                 delegation->stateid.seqid = update->stateid.seqid;
 314                 smp_wmb();
 315                 delegation->type = update->type;
 316         }
 317 }
 318
 319 /**
 320  * nfs_inode_set_delegation - set up a delegation on an inode
 321  * @inode: inode to which delegation applies
 322  * @cred: cred to use for subsequent delegation processing
 323  * @res: new delegation state from server
 324  *
 325  * Returns zero on success, or a negative errno value.
 326  */
 327 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 328 {
 329         struct nfs_server *server = NFS_SERVER(inode);
 330         struct nfs_client *clp = server->nfs_client;
 331         struct nfs_inode *nfsi = NFS_I(inode);
 332         struct nfs_delegation *delegation, *old_delegation;
 333         struct nfs_delegation *freeme = NULL;
 334         int status = 0;
 335
 336         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 337         if (delegation == NULL)
 338                 return -ENOMEM;
 339         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 340         delegation->type = res->delegation_type;
 341         delegation->pagemod_limit = res->pagemod_limit;
 342         delegation->change_attr = inode->i_version;
 343         delegation->cred = get_rpccred(cred);
 344         delegation->inode = inode;
 345         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 346         spin_lock_init(&delegation->lock);
 347
 348         spin_lock(&clp->cl_lock);
 349         old_delegation = rcu_dereference_protected(nfsi->delegation,
 350                                         lockdep_is_held(&clp->cl_lock));
 351         if (old_delegation != NULL) {
 352                 /* Is this an update of the existing delegation? */
 353                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 354                                         &delegation->stateid)) {
 355                         nfs_update_inplace_delegation(old_delegation,
 356                                         delegation);
 357                         goto out;
 358                 }
 359                 /*
 360                  * Deal with broken servers that hand out two
 361                  * delegations for the same file.
 362                  * Allow for upgrades to a WRITE delegation, but
 363                  * nothing else.
 364                  */
 365                 dfprintk(FILE, "%s: server %s handed out "
 366                                 "a duplicate delegation!\n",
 367                                 __func__, clp->cl_hostname);
 368                 if (delegation->type == old_delegation->type ||
 369                     !(delegation->type & FMODE_WRITE)) {
 370                         freeme = delegation;
 371                         delegation = NULL;
 372                         goto out;
 373                 }
 374                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 375                                         &old_delegation->flags))
 376                         goto out;
 377                 freeme = nfs_detach_delegation_locked(nfsi,
 378                                 old_delegation, clp);
 379                 if (freeme == NULL)
 380                         goto out;
 381         }
 382         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 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                                 delegation->type);
 417                 if (!issync || err != -EAGAIN)
 418                         break;
 419                 /*
 420                  * Guard against state recovery
 421                  */
 422                 err = nfs4_wait_clnt_recover(clp);
 423         } while (err == 0);
 424
 425         if (err) {
 426                 nfs_abort_delegation_return(delegation, clp);
 427                 goto out;
 428         }
 429         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 430                 goto out;
 431
 432         err = nfs_do_return_delegation(inode, delegation, issync);
 433 out:
 434         return err;
 435 }
 436
 437 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 438 {
 439         bool ret = false;
 440
 441         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 442                 goto out;
 443         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 444                 ret = true;
 445         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 446                 struct inode *inode;
 447
 448                 spin_lock(&delegation->lock);
 449                 inode = delegation->inode;
 450                 if (inode && list_empty(&NFS_I(inode)->open_files))
 451                         ret = true;
 452                 spin_unlock(&delegation->lock);
 453         }
 454 out:
 455         return ret;
 456 }
 457
 458 /**
 459  * nfs_client_return_marked_delegations - return previously marked delegations
 460  * @clp: nfs_client to process
 461  *
 462  * Note that this function is designed to be called by the state
 463  * manager thread. For this reason, it cannot flush the dirty data,
 464  * since that could deadlock in case of a state recovery error.
 465  *
 466  * Returns zero on success, or a negative errno value.
 467  */
 468 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 469 {
 470         struct nfs_delegation *delegation;
 471         struct nfs_server *server;
 472         struct inode *inode;
 473         int err = 0;
 474
 475 restart:
 476         rcu_read_lock();
 477         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 478                 list_for_each_entry_rcu(delegation, &server->delegations,
 479                                                                 super_list) {
 480                         if (!nfs_delegation_need_return(delegation))
 481                                 continue;
 482                         if (!nfs_sb_active(server->super))
 483                                 continue;
 484                         inode = nfs_delegation_grab_inode(delegation);
 485                         if (inode == NULL) {
 486                                 rcu_read_unlock();
 487                                 nfs_sb_deactive(server->super);
 488                                 goto restart;
 489                         }
 490                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 491                         rcu_read_unlock();
 492
 493                         err = nfs_end_delegation_return(inode, delegation, 0);
 494                         iput(inode);
 495                         nfs_sb_deactive(server->super);
 496                         if (!err)
 497                                 goto restart;
 498                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 499                         return err;
 500                 }
 501         }
 502         rcu_read_unlock();
 503         return 0;
 504 }
 505
 506 /**
 507  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 508  * @inode: inode to process
 509  *
 510  * Does not protect against delegation reclaims, therefore really only safe
 511  * to be called from nfs4_clear_inode().
 512  */
 513 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 514 {
 515         struct nfs_delegation *delegation;
 516
 517         delegation = nfs_inode_detach_delegation(inode);
 518         if (delegation != NULL)
 519                 nfs_do_return_delegation(inode, delegation, 1);
 520 }
 521
 522 /**
 523  * nfs_inode_return_delegation - synchronously return a delegation
 524  * @inode: inode to process
 525  *
 526  * This routine will always flush any dirty data to disk on the
 527  * assumption that if we need to return the delegation, then
 528  * we should stop caching.
 529  *
 530  * Returns zero on success, or a negative errno value.
 531  */
 532 int nfs4_inode_return_delegation(struct inode *inode)
 533 {
 534         struct nfs_inode *nfsi = NFS_I(inode);
 535         struct nfs_delegation *delegation;
 536         int err = 0;
 537
 538         nfs_wb_all(inode);
 539         delegation = nfs_start_delegation_return(nfsi);
 540         if (delegation != NULL)
 541                 err = nfs_end_delegation_return(inode, delegation, 1);
 542         return err;
 543 }
 544
 545 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 546                 struct nfs_delegation *delegation)
 547 {
 548         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 549         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 550 }
 551
 552 static void nfs_mark_return_delegation(struct nfs_server *server,
 553                 struct nfs_delegation *delegation)
 554 {
 555         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 556         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 557 }
 558
 559 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 560 {
 561         struct nfs_delegation *delegation;
 562         bool ret = false;
 563
 564         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 565                 nfs_mark_return_delegation(server, delegation);
 566                 ret = true;
 567         }
 568         return ret;
 569 }
 570
 571 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 572 {
 573         struct nfs_server *server;
 574
 575         rcu_read_lock();
 576         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 577                 nfs_server_mark_return_all_delegations(server);
 578         rcu_read_unlock();
 579 }
 580
 581 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 582 {
 583         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 584                 nfs4_schedule_state_manager(clp);
 585 }
 586
 587 /**
 588  * nfs_expire_all_delegations
 589  * @clp: client to process
 590  *
 591  */
 592 void nfs_expire_all_delegations(struct nfs_client *clp)
 593 {
 594         nfs_client_mark_return_all_delegations(clp);
 595         nfs_delegation_run_state_manager(clp);
 596 }
 597
 598 /**
 599  * nfs_super_return_all_delegations - return delegations for one superblock
 600  * @sb: sb to process
 601  *
 602  */
 603 void nfs_server_return_all_delegations(struct nfs_server *server)
 604 {
 605         struct nfs_client *clp = server->nfs_client;
 606         bool need_wait;
 607
 608         if (clp == NULL)
 609                 return;
 610
 611         rcu_read_lock();
 612         need_wait = nfs_server_mark_return_all_delegations(server);
 613         rcu_read_unlock();
 614
 615         if (need_wait) {
 616                 nfs4_schedule_state_manager(clp);
 617                 nfs4_wait_clnt_recover(clp);
 618         }
 619 }
 620
 621 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 622                                                  fmode_t flags)
 623 {
 624         struct nfs_delegation *delegation;
 625
 626         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 627                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 628                         continue;
 629                 if (delegation->type & flags)
 630                         nfs_mark_return_if_closed_delegation(server, delegation);
 631         }
 632 }
 633
 634 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 635                                                         fmode_t flags)
 636 {
 637         struct nfs_server *server;
 638
 639         rcu_read_lock();
 640         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 641                 nfs_mark_return_unused_delegation_types(server, flags);
 642         rcu_read_unlock();
 643 }
 644
 645 static void nfs_revoke_delegation(struct inode *inode)
 646 {
 647         struct nfs_delegation *delegation;
 648         rcu_read_lock();
 649         delegation = rcu_dereference(NFS_I(inode)->delegation);
 650         if (delegation != NULL) {
 651                 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 652                 nfs_mark_return_delegation(NFS_SERVER(inode), delegation);
 653         }
 654         rcu_read_unlock();
 655 }
 656
 657 void nfs_remove_bad_delegation(struct inode *inode)
 658 {
 659         struct nfs_delegation *delegation;
 660
 661         nfs_revoke_delegation(inode);
 662         delegation = nfs_inode_detach_delegation(inode);
 663         if (delegation) {
 664                 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
 665                 nfs_free_delegation(delegation);
 666         }
 667 }
 668 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 669
 670 /**
 671  * nfs_expire_unused_delegation_types
 672  * @clp: client to process
 673  * @flags: delegation types to expire
 674  *
 675  */
 676 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 677 {
 678         nfs_client_mark_return_unused_delegation_types(clp, flags);
 679         nfs_delegation_run_state_manager(clp);
 680 }
 681
 682 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 683 {
 684         struct nfs_delegation *delegation;
 685
 686         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 687                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 688                         continue;
 689                 nfs_mark_return_if_closed_delegation(server, delegation);
 690         }
 691 }
 692
 693 /**
 694  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 695  * @clp: nfs_client to process
 696  *
 697  */
 698 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 699 {
 700         struct nfs_server *server;
 701
 702         rcu_read_lock();
 703         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 704                 nfs_mark_return_unreferenced_delegations(server);
 705         rcu_read_unlock();
 706
 707         nfs_delegation_run_state_manager(clp);
 708 }
 709
 710 /**
 711  * nfs_async_inode_return_delegation - asynchronously return a delegation
 712  * @inode: inode to process
 713  * @stateid: state ID information
 714  *
 715  * Returns zero on success, or a negative errno value.
 716  */
 717 int nfs_async_inode_return_delegation(struct inode *inode,
 718                                       const nfs4_stateid *stateid)
 719 {
 720         struct nfs_server *server = NFS_SERVER(inode);
 721         struct nfs_client *clp = server->nfs_client;
 722         struct nfs_delegation *delegation;
 723
 724         rcu_read_lock();
 725         delegation = rcu_dereference(NFS_I(inode)->delegation);
 726         if (delegation == NULL)
 727                 goto out_enoent;
 728         if (stateid != NULL &&
 729             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 730                 goto out_enoent;
 731         nfs_mark_return_delegation(server, delegation);
 732         rcu_read_unlock();
 733
 734         nfs_delegation_run_state_manager(clp);
 735         return 0;
 736 out_enoent:
 737         rcu_read_unlock();
 738         return -ENOENT;
 739 }
 740
 741 static struct inode *
 742 nfs_delegation_find_inode_server(struct nfs_server *server,
 743                                  const struct nfs_fh *fhandle)
 744 {
 745         struct nfs_delegation *delegation;
 746         struct inode *res = NULL;
 747
 748         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 749                 spin_lock(&delegation->lock);
 750                 if (delegation->inode != NULL &&
 751                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 752                         res = igrab(delegation->inode);
 753                 }
 754                 spin_unlock(&delegation->lock);
 755                 if (res != NULL)
 756                         break;
 757         }
 758         return res;
 759 }
 760
 761 /**
 762  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 763  * @clp: client state handle
 764  * @fhandle: filehandle from a delegation recall
 765  *
 766  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 767  * cannot be found.
 768  */
 769 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 770                                         const struct nfs_fh *fhandle)
 771 {
 772         struct nfs_server *server;
 773         struct inode *res = NULL;
 774
 775         rcu_read_lock();
 776         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 777                 res = nfs_delegation_find_inode_server(server, fhandle);
 778                 if (res != NULL)
 779                         break;
 780         }
 781         rcu_read_unlock();
 782         return res;
 783 }
 784
 785 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 786 {
 787         struct nfs_delegation *delegation;
 788
 789         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
 790                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 791 }
 792
 793 /**
 794  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 795  * @clp: nfs_client to process
 796  *
 797  */
 798 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 799 {
 800         struct nfs_server *server;
 801
 802         rcu_read_lock();
 803         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 804                 nfs_delegation_mark_reclaim_server(server);
 805         rcu_read_unlock();
 806 }
 807
 808 /**
 809  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 810  * @clp: nfs_client to process
 811  *
 812  */
 813 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 814 {
 815         struct nfs_delegation *delegation;
 816         struct nfs_server *server;
 817         struct inode *inode;
 818
 819 restart:
 820         rcu_read_lock();
 821         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 822                 list_for_each_entry_rcu(delegation, &server->delegations,
 823                                                                 super_list) {
 824                         if (test_bit(NFS_DELEGATION_RETURNING,
 825                                                 &delegation->flags))
 826                                 continue;
 827                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 828                                                 &delegation->flags) == 0)
 829                                 continue;
 830                         if (!nfs_sb_active(server->super))
 831                                 continue;
 832                         inode = nfs_delegation_grab_inode(delegation);
 833                         if (inode == NULL) {
 834                                 rcu_read_unlock();
 835                                 nfs_sb_deactive(server->super);
 836                                 goto restart;
 837                         }
 838                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 839                         rcu_read_unlock();
 840                         if (delegation != NULL) {
 841                                 delegation = nfs_detach_delegation(NFS_I(inode),
 842                                         delegation, server);
 843                                 if (delegation != NULL)
 844                                         nfs_free_delegation(delegation);
 845                         }
 846                         iput(inode);
 847                         nfs_sb_deactive(server->super);
 848                         goto restart;
 849                 }
 850         }
 851         rcu_read_unlock();
 852 }
 853
 854 /**
 855  * nfs_delegations_present - check for existence of delegations
 856  * @clp: client state handle
 857  *
 858  * Returns one if there are any nfs_delegation structures attached
 859  * to this nfs_client.
 860  */
 861 int nfs_delegations_present(struct nfs_client *clp)
 862 {
 863         struct nfs_server *server;
 864         int ret = 0;
 865
 866         rcu_read_lock();
 867         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 868                 if (!list_empty(&server->delegations)) {
 869                         ret = 1;
 870                         break;
 871                 }
 872         rcu_read_unlock();
 873         return ret;
 874 }
 875
 876 /**
 877  * nfs4_copy_delegation_stateid - Copy inode's state ID information
 878  * @inode: inode to check
 879  * @flags: delegation type requirement
 880  * @dst: stateid data structure to fill in
 881  * @cred: optional argument to retrieve credential
 882  *
 883  * Returns "true" and fills in "dst->data" * if inode had a delegation,
 884  * otherwise "false" is returned.
 885  */
 886 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
 887                 nfs4_stateid *dst, struct rpc_cred **cred)
 888 {
 889         struct nfs_inode *nfsi = NFS_I(inode);
 890         struct nfs_delegation *delegation;
 891         bool ret;
 892
 893         flags &= FMODE_READ|FMODE_WRITE;
 894         rcu_read_lock();
 895         delegation = rcu_dereference(nfsi->delegation);
 896         ret = (delegation != NULL && (delegation->type & flags) == flags);
 897         if (ret) {
 898                 nfs4_stateid_copy(dst, &delegation->stateid);
 899                 nfs_mark_delegation_referenced(delegation);
 900                 if (cred)
 901                         *cred = get_rpccred(delegation->cred);
 902         }
 903         rcu_read_unlock();
 904         return ret;
 905 }
 906
 907 /**
 908  * nfs4_delegation_flush_on_close - Check if we must flush file on close
 909  * @inode: inode to check
 910  *
 911  * This function checks the number of outstanding writes to the file
 912  * against the delegation 'space_limit' field to see if
 913  * the spec requires us to flush the file on close.
 914  */
 915 bool nfs4_delegation_flush_on_close(const struct inode *inode)
 916 {
 917         struct nfs_inode *nfsi = NFS_I(inode);
 918         struct nfs_delegation *delegation;
 919         bool ret = true;
 920
 921         rcu_read_lock();
 922         delegation = rcu_dereference(nfsi->delegation);
 923         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
 924                 goto out;
 925         if (nfsi->nrequests < delegation->pagemod_limit)
 926                 ret = false;
 927 out:
 928         rcu_read_unlock();
 929         return ret;
 930 }