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 struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
  56 {
  57         struct nfs_delegation *delegation;
  58
  59         delegation = rcu_dereference(NFS_I(inode)->delegation);
  60         if (nfs4_is_valid_delegation(delegation, 0))
  61                 return delegation;
  62         return NULL;
  63 }
  64
  65 static int
  66 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  67 {
  68         struct nfs_delegation *delegation;
  69         int ret = 0;
  70
  71         flags &= FMODE_READ|FMODE_WRITE;
  72         rcu_read_lock();
  73         delegation = rcu_dereference(NFS_I(inode)->delegation);
  74         if (nfs4_is_valid_delegation(delegation, flags)) {
  75                 if (mark)
  76                         nfs_mark_delegation_referenced(delegation);
  77                 ret = 1;
  78         }
  79         rcu_read_unlock();
  80         return ret;
  81 }
  82 /**
  83  * nfs_have_delegation - check if inode has a delegation, mark it
  84  * NFS_DELEGATION_REFERENCED if there is one.
  85  * @inode: inode to check
  86  * @flags: delegation types to check for
  87  *
  88  * Returns one if inode has the indicated delegation, otherwise zero.
  89  */
  90 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  91 {
  92         return nfs4_do_check_delegation(inode, flags, true);
  93 }
  94
  95 /*
  96  * nfs4_check_delegation - check if inode has a delegation, do not mark
  97  * NFS_DELEGATION_REFERENCED if it has one.
  98  */
  99 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
 100 {
 101         return nfs4_do_check_delegation(inode, flags, false);
 102 }
 103
 104 static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
 105 {
 106         struct inode *inode = state->inode;
 107         struct file_lock *fl;
 108         struct file_lock_context *flctx = inode->i_flctx;
 109         struct list_head *list;
 110         int status = 0;
 111
 112         if (flctx == NULL)
 113                 goto out;
 114
 115         list = &flctx->flc_posix;
 116         spin_lock(&flctx->flc_lock);
 117 restart:
 118         list_for_each_entry(fl, list, fl_list) {
 119                 if (nfs_file_open_context(fl->fl_file)->state != state)
 120                         continue;
 121                 spin_unlock(&flctx->flc_lock);
 122                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 123                 if (status < 0)
 124                         goto out;
 125                 spin_lock(&flctx->flc_lock);
 126         }
 127         if (list == &flctx->flc_posix) {
 128                 list = &flctx->flc_flock;
 129                 goto restart;
 130         }
 131         spin_unlock(&flctx->flc_lock);
 132 out:
 133         return status;
 134 }
 135
 136 static int nfs_delegation_claim_opens(struct inode *inode,
 137                 const nfs4_stateid *stateid, fmode_t type)
 138 {
 139         struct nfs_inode *nfsi = NFS_I(inode);
 140         struct nfs_open_context *ctx;
 141         struct nfs4_state_owner *sp;
 142         struct nfs4_state *state;
 143         unsigned int seq;
 144         int err;
 145
 146 again:
 147         spin_lock(&inode->i_lock);
 148         list_for_each_entry(ctx, &nfsi->open_files, list) {
 149                 state = ctx->state;
 150                 if (state == NULL)
 151                         continue;
 152                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 153                         continue;
 154                 if (!nfs4_valid_open_stateid(state))
 155                         continue;
 156                 if (!nfs4_stateid_match(&state->stateid, stateid))
 157                         continue;
 158                 get_nfs_open_context(ctx);
 159                 spin_unlock(&inode->i_lock);
 160                 sp = state->owner;
 161                 /* Block nfs4_proc_unlck */
 162                 mutex_lock(&sp->so_delegreturn_mutex);
 163                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 164                 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
 165                 if (!err)
 166                         err = nfs_delegation_claim_locks(state, stateid);
 167                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 168                         err = -EAGAIN;
 169                 mutex_unlock(&sp->so_delegreturn_mutex);
 170                 put_nfs_open_context(ctx);
 171                 if (err != 0)
 172                         return err;
 173                 goto again;
 174         }
 175         spin_unlock(&inode->i_lock);
 176         return 0;
 177 }
 178
 179 /**
 180  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 181  * @inode: inode to process
 182  * @cred: credential to use for request
 183  * @res: new delegation state from server
 184  *
 185  */
 186 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
 187                                   struct nfs_openres *res)
 188 {
 189         struct nfs_delegation *delegation;
 190         struct rpc_cred *oldcred = NULL;
 191
 192         rcu_read_lock();
 193         delegation = rcu_dereference(NFS_I(inode)->delegation);
 194         if (delegation != NULL) {
 195                 spin_lock(&delegation->lock);
 196                 if (delegation->inode != NULL) {
 197                         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 198                         delegation->type = res->delegation_type;
 199                         delegation->pagemod_limit = res->pagemod_limit;
 200                         oldcred = delegation->cred;
 201                         delegation->cred = get_rpccred(cred);
 202                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 203                                   &delegation->flags);
 204                         spin_unlock(&delegation->lock);
 205                         rcu_read_unlock();
 206                         put_rpccred(oldcred);
 207                         trace_nfs4_reclaim_delegation(inode, res->delegation_type);
 208                 } else {
 209                         /* We appear to have raced with a delegation return. */
 210                         spin_unlock(&delegation->lock);
 211                         rcu_read_unlock();
 212                         nfs_inode_set_delegation(inode, cred, res);
 213                 }
 214         } else {
 215                 rcu_read_unlock();
 216         }
 217 }
 218
 219 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 220 {
 221         int res = 0;
 222
 223         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 224                 res = nfs4_proc_delegreturn(inode,
 225                                 delegation->cred,
 226                                 &delegation->stateid,
 227                                 issync);
 228         nfs_free_delegation(delegation);
 229         return res;
 230 }
 231
 232 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 233 {
 234         struct inode *inode = NULL;
 235
 236         spin_lock(&delegation->lock);
 237         if (delegation->inode != NULL)
 238                 inode = igrab(delegation->inode);
 239         spin_unlock(&delegation->lock);
 240         return inode;
 241 }
 242
 243 static struct nfs_delegation *
 244 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 245 {
 246         struct nfs_delegation *ret = NULL;
 247         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 248
 249         if (delegation == NULL)
 250                 goto out;
 251         spin_lock(&delegation->lock);
 252         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 253                 ret = delegation;
 254         spin_unlock(&delegation->lock);
 255 out:
 256         return ret;
 257 }
 258
 259 static struct nfs_delegation *
 260 nfs_start_delegation_return(struct nfs_inode *nfsi)
 261 {
 262         struct nfs_delegation *delegation;
 263
 264         rcu_read_lock();
 265         delegation = nfs_start_delegation_return_locked(nfsi);
 266         rcu_read_unlock();
 267         return delegation;
 268 }
 269
 270 static void
 271 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 272                 struct nfs_client *clp)
 273 {
 274
 275         spin_lock(&delegation->lock);
 276         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 277         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 278         spin_unlock(&delegation->lock);
 279         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 280 }
 281
 282 static struct nfs_delegation *
 283 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 284                 struct nfs_delegation *delegation,
 285                 struct nfs_client *clp)
 286 {
 287         struct nfs_delegation *deleg_cur =
 288                 rcu_dereference_protected(nfsi->delegation,
 289                                 lockdep_is_held(&clp->cl_lock));
 290
 291         if (deleg_cur == NULL || delegation != deleg_cur)
 292                 return NULL;
 293
 294         spin_lock(&delegation->lock);
 295         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 296         list_del_rcu(&delegation->super_list);
 297         delegation->inode = NULL;
 298         rcu_assign_pointer(nfsi->delegation, NULL);
 299         spin_unlock(&delegation->lock);
 300         return delegation;
 301 }
 302
 303 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 304                 struct nfs_delegation *delegation,
 305                 struct nfs_server *server)
 306 {
 307         struct nfs_client *clp = server->nfs_client;
 308
 309         spin_lock(&clp->cl_lock);
 310         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 311         spin_unlock(&clp->cl_lock);
 312         return delegation;
 313 }
 314
 315 static struct nfs_delegation *
 316 nfs_inode_detach_delegation(struct inode *inode)
 317 {
 318         struct nfs_inode *nfsi = NFS_I(inode);
 319         struct nfs_server *server = NFS_SERVER(inode);
 320         struct nfs_delegation *delegation;
 321
 322         delegation = nfs_start_delegation_return(nfsi);
 323         if (delegation == NULL)
 324                 return NULL;
 325         return nfs_detach_delegation(nfsi, delegation, server);
 326 }
 327
 328 static void
 329 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 330                 const struct nfs_delegation *update)
 331 {
 332         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 333                 delegation->stateid.seqid = update->stateid.seqid;
 334                 smp_wmb();
 335                 delegation->type = update->type;
 336         }
 337 }
 338
 339 /**
 340  * nfs_inode_set_delegation - set up a delegation on an inode
 341  * @inode: inode to which delegation applies
 342  * @cred: cred to use for subsequent delegation processing
 343  * @res: new delegation state from server
 344  *
 345  * Returns zero on success, or a negative errno value.
 346  */
 347 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 348 {
 349         struct nfs_server *server = NFS_SERVER(inode);
 350         struct nfs_client *clp = server->nfs_client;
 351         struct nfs_inode *nfsi = NFS_I(inode);
 352         struct nfs_delegation *delegation, *old_delegation;
 353         struct nfs_delegation *freeme = NULL;
 354         int status = 0;
 355
 356         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 357         if (delegation == NULL)
 358                 return -ENOMEM;
 359         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 360         delegation->type = res->delegation_type;
 361         delegation->pagemod_limit = res->pagemod_limit;
 362         delegation->change_attr = inode->i_version;
 363         delegation->cred = get_rpccred(cred);
 364         delegation->inode = inode;
 365         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 366         spin_lock_init(&delegation->lock);
 367
 368         spin_lock(&clp->cl_lock);
 369         old_delegation = rcu_dereference_protected(nfsi->delegation,
 370                                         lockdep_is_held(&clp->cl_lock));
 371         if (old_delegation != NULL) {
 372                 /* Is this an update of the existing delegation? */
 373                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 374                                         &delegation->stateid)) {
 375                         nfs_update_inplace_delegation(old_delegation,
 376                                         delegation);
 377                         goto out;
 378                 }
 379                 /*
 380                  * Deal with broken servers that hand out two
 381                  * delegations for the same file.
 382                  * Allow for upgrades to a WRITE delegation, but
 383                  * nothing else.
 384                  */
 385                 dfprintk(FILE, "%s: server %s handed out "
 386                                 "a duplicate delegation!\n",
 387                                 __func__, clp->cl_hostname);
 388                 if (delegation->type == old_delegation->type ||
 389                     !(delegation->type & FMODE_WRITE)) {
 390                         freeme = delegation;
 391                         delegation = NULL;
 392                         goto out;
 393                 }
 394                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 395                                         &old_delegation->flags))
 396                         goto out;
 397                 freeme = nfs_detach_delegation_locked(nfsi,
 398                                 old_delegation, clp);
 399                 if (freeme == NULL)
 400                         goto out;
 401         }
 402         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 403         rcu_assign_pointer(nfsi->delegation, delegation);
 404         delegation = NULL;
 405
 406         /* Ensure we revalidate the attributes and page cache! */
 407         spin_lock(&inode->i_lock);
 408         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 409         spin_unlock(&inode->i_lock);
 410         trace_nfs4_set_delegation(inode, res->delegation_type);
 411
 412 out:
 413         spin_unlock(&clp->cl_lock);
 414         if (delegation != NULL)
 415                 nfs_free_delegation(delegation);
 416         if (freeme != NULL)
 417                 nfs_do_return_delegation(inode, freeme, 0);
 418         return status;
 419 }
 420
 421 /*
 422  * Basic procedure for returning a delegation to the server
 423  */
 424 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 425 {
 426         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 427         struct nfs_inode *nfsi = NFS_I(inode);
 428         int err = 0;
 429
 430         if (delegation == NULL)
 431                 return 0;
 432         do {
 433                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 434                         break;
 435                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 436                                 delegation->type);
 437                 if (!issync || err != -EAGAIN)
 438                         break;
 439                 /*
 440                  * Guard against state recovery
 441                  */
 442                 err = nfs4_wait_clnt_recover(clp);
 443         } while (err == 0);
 444
 445         if (err) {
 446                 nfs_abort_delegation_return(delegation, clp);
 447                 goto out;
 448         }
 449         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 450                 goto out;
 451
 452         err = nfs_do_return_delegation(inode, delegation, issync);
 453 out:
 454         return err;
 455 }
 456
 457 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 458 {
 459         bool ret = false;
 460
 461         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 462                 goto out;
 463         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 464                 ret = true;
 465         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 466                 struct inode *inode;
 467
 468                 spin_lock(&delegation->lock);
 469                 inode = delegation->inode;
 470                 if (inode && list_empty(&NFS_I(inode)->open_files))
 471                         ret = true;
 472                 spin_unlock(&delegation->lock);
 473         }
 474 out:
 475         return ret;
 476 }
 477
 478 /**
 479  * nfs_client_return_marked_delegations - return previously marked delegations
 480  * @clp: nfs_client to process
 481  *
 482  * Note that this function is designed to be called by the state
 483  * manager thread. For this reason, it cannot flush the dirty data,
 484  * since that could deadlock in case of a state recovery error.
 485  *
 486  * Returns zero on success, or a negative errno value.
 487  */
 488 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 489 {
 490         struct nfs_delegation *delegation;
 491         struct nfs_server *server;
 492         struct inode *inode;
 493         int err = 0;
 494
 495 restart:
 496         rcu_read_lock();
 497         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 498                 list_for_each_entry_rcu(delegation, &server->delegations,
 499                                                                 super_list) {
 500                         if (!nfs_delegation_need_return(delegation))
 501                                 continue;
 502                         if (!nfs_sb_active(server->super))
 503                                 continue;
 504                         inode = nfs_delegation_grab_inode(delegation);
 505                         if (inode == NULL) {
 506                                 rcu_read_unlock();
 507                                 nfs_sb_deactive(server->super);
 508                                 goto restart;
 509                         }
 510                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 511                         rcu_read_unlock();
 512
 513                         err = nfs_end_delegation_return(inode, delegation, 0);
 514                         iput(inode);
 515                         nfs_sb_deactive(server->super);
 516                         if (!err)
 517                                 goto restart;
 518                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 519                         return err;
 520                 }
 521         }
 522         rcu_read_unlock();
 523         return 0;
 524 }
 525
 526 /**
 527  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 528  * @inode: inode to process
 529  *
 530  * Does not protect against delegation reclaims, therefore really only safe
 531  * to be called from nfs4_clear_inode().
 532  */
 533 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 534 {
 535         struct nfs_delegation *delegation;
 536
 537         delegation = nfs_inode_detach_delegation(inode);
 538         if (delegation != NULL)
 539                 nfs_do_return_delegation(inode, delegation, 1);
 540 }
 541
 542 /**
 543  * nfs_inode_return_delegation - synchronously return a delegation
 544  * @inode: inode to process
 545  *
 546  * This routine will always flush any dirty data to disk on the
 547  * assumption that if we need to return the delegation, then
 548  * we should stop caching.
 549  *
 550  * Returns zero on success, or a negative errno value.
 551  */
 552 int nfs4_inode_return_delegation(struct inode *inode)
 553 {
 554         struct nfs_inode *nfsi = NFS_I(inode);
 555         struct nfs_delegation *delegation;
 556         int err = 0;
 557
 558         nfs_wb_all(inode);
 559         delegation = nfs_start_delegation_return(nfsi);
 560         if (delegation != NULL)
 561                 err = nfs_end_delegation_return(inode, delegation, 1);
 562         return err;
 563 }
 564
 565 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 566                 struct nfs_delegation *delegation)
 567 {
 568         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 569         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 570 }
 571
 572 static void nfs_mark_return_delegation(struct nfs_server *server,
 573                 struct nfs_delegation *delegation)
 574 {
 575         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 576         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 577 }
 578
 579 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 580 {
 581         struct nfs_delegation *delegation;
 582         bool ret = false;
 583
 584         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 585                 nfs_mark_return_delegation(server, delegation);
 586                 ret = true;
 587         }
 588         return ret;
 589 }
 590
 591 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 592 {
 593         struct nfs_server *server;
 594
 595         rcu_read_lock();
 596         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 597                 nfs_server_mark_return_all_delegations(server);
 598         rcu_read_unlock();
 599 }
 600
 601 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 602 {
 603         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 604                 nfs4_schedule_state_manager(clp);
 605 }
 606
 607 /**
 608  * nfs_expire_all_delegations
 609  * @clp: client to process
 610  *
 611  */
 612 void nfs_expire_all_delegations(struct nfs_client *clp)
 613 {
 614         nfs_client_mark_return_all_delegations(clp);
 615         nfs_delegation_run_state_manager(clp);
 616 }
 617
 618 /**
 619  * nfs_super_return_all_delegations - return delegations for one superblock
 620  * @sb: sb to process
 621  *
 622  */
 623 void nfs_server_return_all_delegations(struct nfs_server *server)
 624 {
 625         struct nfs_client *clp = server->nfs_client;
 626         bool need_wait;
 627
 628         if (clp == NULL)
 629                 return;
 630
 631         rcu_read_lock();
 632         need_wait = nfs_server_mark_return_all_delegations(server);
 633         rcu_read_unlock();
 634
 635         if (need_wait) {
 636                 nfs4_schedule_state_manager(clp);
 637                 nfs4_wait_clnt_recover(clp);
 638         }
 639 }
 640
 641 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 642                                                  fmode_t flags)
 643 {
 644         struct nfs_delegation *delegation;
 645
 646         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 647                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 648                         continue;
 649                 if (delegation->type & flags)
 650                         nfs_mark_return_if_closed_delegation(server, delegation);
 651         }
 652 }
 653
 654 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 655                                                         fmode_t flags)
 656 {
 657         struct nfs_server *server;
 658
 659         rcu_read_lock();
 660         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 661                 nfs_mark_return_unused_delegation_types(server, flags);
 662         rcu_read_unlock();
 663 }
 664
 665 static void nfs_revoke_delegation(struct inode *inode)
 666 {
 667         struct nfs_delegation *delegation;
 668         rcu_read_lock();
 669         delegation = rcu_dereference(NFS_I(inode)->delegation);
 670         if (delegation != NULL) {
 671                 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 672                 nfs_mark_return_delegation(NFS_SERVER(inode), delegation);
 673         }
 674         rcu_read_unlock();
 675 }
 676
 677 void nfs_remove_bad_delegation(struct inode *inode)
 678 {
 679         struct nfs_delegation *delegation;
 680
 681         nfs_revoke_delegation(inode);
 682         delegation = nfs_inode_detach_delegation(inode);
 683         if (delegation) {
 684                 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
 685                 nfs_free_delegation(delegation);
 686         }
 687 }
 688 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 689
 690 /**
 691  * nfs_expire_unused_delegation_types
 692  * @clp: client to process
 693  * @flags: delegation types to expire
 694  *
 695  */
 696 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 697 {
 698         nfs_client_mark_return_unused_delegation_types(clp, flags);
 699         nfs_delegation_run_state_manager(clp);
 700 }
 701
 702 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 703 {
 704         struct nfs_delegation *delegation;
 705
 706         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 707                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 708                         continue;
 709                 nfs_mark_return_if_closed_delegation(server, delegation);
 710         }
 711 }
 712
 713 /**
 714  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 715  * @clp: nfs_client to process
 716  *
 717  */
 718 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 719 {
 720         struct nfs_server *server;
 721
 722         rcu_read_lock();
 723         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 724                 nfs_mark_return_unreferenced_delegations(server);
 725         rcu_read_unlock();
 726
 727         nfs_delegation_run_state_manager(clp);
 728 }
 729
 730 /**
 731  * nfs_async_inode_return_delegation - asynchronously return a delegation
 732  * @inode: inode to process
 733  * @stateid: state ID information
 734  *
 735  * Returns zero on success, or a negative errno value.
 736  */
 737 int nfs_async_inode_return_delegation(struct inode *inode,
 738                                       const nfs4_stateid *stateid)
 739 {
 740         struct nfs_server *server = NFS_SERVER(inode);
 741         struct nfs_client *clp = server->nfs_client;
 742         struct nfs_delegation *delegation;
 743
 744         rcu_read_lock();
 745         delegation = rcu_dereference(NFS_I(inode)->delegation);
 746         if (delegation == NULL)
 747                 goto out_enoent;
 748         if (stateid != NULL &&
 749             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 750                 goto out_enoent;
 751         nfs_mark_return_delegation(server, delegation);
 752         rcu_read_unlock();
 753
 754         nfs_delegation_run_state_manager(clp);
 755         return 0;
 756 out_enoent:
 757         rcu_read_unlock();
 758         return -ENOENT;
 759 }
 760
 761 static struct inode *
 762 nfs_delegation_find_inode_server(struct nfs_server *server,
 763                                  const struct nfs_fh *fhandle)
 764 {
 765         struct nfs_delegation *delegation;
 766         struct inode *res = NULL;
 767
 768         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 769                 spin_lock(&delegation->lock);
 770                 if (delegation->inode != NULL &&
 771                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 772                         res = igrab(delegation->inode);
 773                 }
 774                 spin_unlock(&delegation->lock);
 775                 if (res != NULL)
 776                         break;
 777         }
 778         return res;
 779 }
 780
 781 /**
 782  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 783  * @clp: client state handle
 784  * @fhandle: filehandle from a delegation recall
 785  *
 786  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 787  * cannot be found.
 788  */
 789 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 790                                         const struct nfs_fh *fhandle)
 791 {
 792         struct nfs_server *server;
 793         struct inode *res = NULL;
 794
 795         rcu_read_lock();
 796         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 797                 res = nfs_delegation_find_inode_server(server, fhandle);
 798                 if (res != NULL)
 799                         break;
 800         }
 801         rcu_read_unlock();
 802         return res;
 803 }
 804
 805 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 806 {
 807         struct nfs_delegation *delegation;
 808
 809         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
 810                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 811 }
 812
 813 /**
 814  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 815  * @clp: nfs_client to process
 816  *
 817  */
 818 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 819 {
 820         struct nfs_server *server;
 821
 822         rcu_read_lock();
 823         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 824                 nfs_delegation_mark_reclaim_server(server);
 825         rcu_read_unlock();
 826 }
 827
 828 /**
 829  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 830  * @clp: nfs_client to process
 831  *
 832  */
 833 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 834 {
 835         struct nfs_delegation *delegation;
 836         struct nfs_server *server;
 837         struct inode *inode;
 838
 839 restart:
 840         rcu_read_lock();
 841         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 842                 list_for_each_entry_rcu(delegation, &server->delegations,
 843                                                                 super_list) {
 844                         if (test_bit(NFS_DELEGATION_RETURNING,
 845                                                 &delegation->flags))
 846                                 continue;
 847                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 848                                                 &delegation->flags) == 0)
 849                                 continue;
 850                         if (!nfs_sb_active(server->super))
 851                                 continue;
 852                         inode = nfs_delegation_grab_inode(delegation);
 853                         if (inode == NULL) {
 854                                 rcu_read_unlock();
 855                                 nfs_sb_deactive(server->super);
 856                                 goto restart;
 857                         }
 858                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 859                         rcu_read_unlock();
 860                         if (delegation != NULL) {
 861                                 delegation = nfs_detach_delegation(NFS_I(inode),
 862                                         delegation, server);
 863                                 if (delegation != NULL)
 864                                         nfs_free_delegation(delegation);
 865                         }
 866                         iput(inode);
 867                         nfs_sb_deactive(server->super);
 868                         goto restart;
 869                 }
 870         }
 871         rcu_read_unlock();
 872 }
 873
 874 /**
 875  * nfs_delegations_present - check for existence of delegations
 876  * @clp: client state handle
 877  *
 878  * Returns one if there are any nfs_delegation structures attached
 879  * to this nfs_client.
 880  */
 881 int nfs_delegations_present(struct nfs_client *clp)
 882 {
 883         struct nfs_server *server;
 884         int ret = 0;
 885
 886         rcu_read_lock();
 887         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 888                 if (!list_empty(&server->delegations)) {
 889                         ret = 1;
 890                         break;
 891                 }
 892         rcu_read_unlock();
 893         return ret;
 894 }
 895
 896 /**
 897  * nfs4_copy_delegation_stateid - Copy inode's state ID information
 898  * @dst: stateid data structure to fill in
 899  * @inode: inode to check
 900  * @flags: delegation type requirement
 901  *
 902  * Returns "true" and fills in "dst->data" * if inode had a delegation,
 903  * otherwise "false" is returned.
 904  */
 905 bool nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode,
 906                 fmode_t flags)
 907 {
 908         struct nfs_inode *nfsi = NFS_I(inode);
 909         struct nfs_delegation *delegation;
 910         bool ret;
 911
 912         flags &= FMODE_READ|FMODE_WRITE;
 913         rcu_read_lock();
 914         delegation = rcu_dereference(nfsi->delegation);
 915         ret = nfs4_is_valid_delegation(delegation, flags);
 916         if (ret) {
 917                 nfs4_stateid_copy(dst, &delegation->stateid);
 918                 nfs_mark_delegation_referenced(delegation);
 919         }
 920         rcu_read_unlock();
 921         return ret;
 922 }
 923
 924 /**
 925  * nfs4_delegation_flush_on_close - Check if we must flush file on close
 926  * @inode: inode to check
 927  *
 928  * This function checks the number of outstanding writes to the file
 929  * against the delegation 'space_limit' field to see if
 930  * the spec requires us to flush the file on close.
 931  */
 932 bool nfs4_delegation_flush_on_close(const struct inode *inode)
 933 {
 934         struct nfs_inode *nfsi = NFS_I(inode);
 935         struct nfs_delegation *delegation;
 936         bool ret = true;
 937
 938         rcu_read_lock();
 939         delegation = rcu_dereference(nfsi->delegation);
 940         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
 941                 goto out;
 942         if (nfsi->nrequests < delegation->pagemod_limit)
 943                 ret = false;
 944 out:
 945         rcu_read_unlock();
 946         return ret;
 947 }