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 /**
 310  * nfs_inode_set_delegation - set up a delegation on an inode
 311  * @inode: inode to which delegation applies
 312  * @cred: cred to use for subsequent delegation processing
 313  * @res: new delegation state from server
 314  *
 315  * Returns zero on success, or a negative errno value.
 316  */
 317 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 318 {
 319         struct nfs_server *server = NFS_SERVER(inode);
 320         struct nfs_client *clp = server->nfs_client;
 321         struct nfs_inode *nfsi = NFS_I(inode);
 322         struct nfs_delegation *delegation, *old_delegation;
 323         struct nfs_delegation *freeme = NULL;
 324         int status = 0;
 325
 326         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 327         if (delegation == NULL)
 328                 return -ENOMEM;
 329         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 330         delegation->type = res->delegation_type;
 331         delegation->maxsize = res->maxsize;
 332         delegation->change_attr = inode->i_version;
 333         delegation->cred = get_rpccred(cred);
 334         delegation->inode = inode;
 335         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 336         spin_lock_init(&delegation->lock);
 337
 338         spin_lock(&clp->cl_lock);
 339         old_delegation = rcu_dereference_protected(nfsi->delegation,
 340                                         lockdep_is_held(&clp->cl_lock));
 341         if (old_delegation != NULL) {
 342                 if (nfs4_stateid_match(&delegation->stateid,
 343                                         &old_delegation->stateid) &&
 344                                 delegation->type == old_delegation->type) {
 345                         goto out;
 346                 }
 347                 /*
 348                  * Deal with broken servers that hand out two
 349                  * delegations for the same file.
 350                  * Allow for upgrades to a WRITE delegation, but
 351                  * nothing else.
 352                  */
 353                 dfprintk(FILE, "%s: server %s handed out "
 354                                 "a duplicate delegation!\n",
 355                                 __func__, clp->cl_hostname);
 356                 if (delegation->type == old_delegation->type ||
 357                     !(delegation->type & FMODE_WRITE)) {
 358                         freeme = delegation;
 359                         delegation = NULL;
 360                         goto out;
 361                 }
 362                 freeme = nfs_detach_delegation_locked(nfsi,
 363                                 old_delegation, clp);
 364                 if (freeme == NULL)
 365                         goto out;
 366         }
 367         list_add_rcu(&delegation->super_list, &server->delegations);
 368         nfsi->delegation_state = delegation->type;
 369         rcu_assign_pointer(nfsi->delegation, delegation);
 370         delegation = NULL;
 371
 372         /* Ensure we revalidate the attributes and page cache! */
 373         spin_lock(&inode->i_lock);
 374         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 375         spin_unlock(&inode->i_lock);
 376         trace_nfs4_set_delegation(inode, res->delegation_type);
 377
 378 out:
 379         spin_unlock(&clp->cl_lock);
 380         if (delegation != NULL)
 381                 nfs_free_delegation(delegation);
 382         if (freeme != NULL)
 383                 nfs_do_return_delegation(inode, freeme, 0);
 384         return status;
 385 }
 386
 387 /*
 388  * Basic procedure for returning a delegation to the server
 389  */
 390 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 391 {
 392         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 393         struct nfs_inode *nfsi = NFS_I(inode);
 394         int err = 0;
 395
 396         if (delegation == NULL)
 397                 return 0;
 398         do {
 399                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 400                         break;
 401                 err = nfs_delegation_claim_opens(inode, &delegation->stateid);
 402                 if (!issync || err != -EAGAIN)
 403                         break;
 404                 /*
 405                  * Guard against state recovery
 406                  */
 407                 err = nfs4_wait_clnt_recover(clp);
 408         } while (err == 0);
 409
 410         if (err) {
 411                 nfs_abort_delegation_return(delegation, clp);
 412                 goto out;
 413         }
 414         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 415                 goto out;
 416
 417         err = nfs_do_return_delegation(inode, delegation, issync);
 418 out:
 419         return err;
 420 }
 421
 422 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 423 {
 424         bool ret = false;
 425
 426         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 427                 ret = true;
 428         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 429                 struct inode *inode;
 430
 431                 spin_lock(&delegation->lock);
 432                 inode = delegation->inode;
 433                 if (inode && list_empty(&NFS_I(inode)->open_files))
 434                         ret = true;
 435                 spin_unlock(&delegation->lock);
 436         }
 437         return ret;
 438 }
 439
 440 /**
 441  * nfs_client_return_marked_delegations - return previously marked delegations
 442  * @clp: nfs_client to process
 443  *
 444  * Note that this function is designed to be called by the state
 445  * manager thread. For this reason, it cannot flush the dirty data,
 446  * since that could deadlock in case of a state recovery error.
 447  *
 448  * Returns zero on success, or a negative errno value.
 449  */
 450 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 451 {
 452         struct nfs_delegation *delegation;
 453         struct nfs_server *server;
 454         struct inode *inode;
 455         int err = 0;
 456
 457 restart:
 458         rcu_read_lock();
 459         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 460                 list_for_each_entry_rcu(delegation, &server->delegations,
 461                                                                 super_list) {
 462                         if (!nfs_delegation_need_return(delegation))
 463                                 continue;
 464                         inode = nfs_delegation_grab_inode(delegation);
 465                         if (inode == NULL)
 466                                 continue;
 467                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 468                         rcu_read_unlock();
 469
 470                         err = nfs_end_delegation_return(inode, delegation, 0);
 471                         iput(inode);
 472                         if (!err)
 473                                 goto restart;
 474                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 475                         return err;
 476                 }
 477         }
 478         rcu_read_unlock();
 479         return 0;
 480 }
 481
 482 /**
 483  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 484  * @inode: inode to process
 485  *
 486  * Does not protect against delegation reclaims, therefore really only safe
 487  * to be called from nfs4_clear_inode().
 488  */
 489 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 490 {
 491         struct nfs_delegation *delegation;
 492
 493         delegation = nfs_inode_detach_delegation(inode);
 494         if (delegation != NULL)
 495                 nfs_do_return_delegation(inode, delegation, 0);
 496 }
 497
 498 /**
 499  * nfs_inode_return_delegation - synchronously return a delegation
 500  * @inode: inode to process
 501  *
 502  * This routine will always flush any dirty data to disk on the
 503  * assumption that if we need to return the delegation, then
 504  * we should stop caching.
 505  *
 506  * Returns zero on success, or a negative errno value.
 507  */
 508 int nfs4_inode_return_delegation(struct inode *inode)
 509 {
 510         struct nfs_inode *nfsi = NFS_I(inode);
 511         struct nfs_delegation *delegation;
 512         int err = 0;
 513
 514         nfs_wb_all(inode);
 515         delegation = nfs_start_delegation_return(nfsi);
 516         if (delegation != NULL)
 517                 err = nfs_end_delegation_return(inode, delegation, 1);
 518         return err;
 519 }
 520
 521 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 522                 struct nfs_delegation *delegation)
 523 {
 524         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 525         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 526 }
 527
 528 static void nfs_mark_return_delegation(struct nfs_server *server,
 529                 struct nfs_delegation *delegation)
 530 {
 531         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 532         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 533 }
 534
 535 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 536 {
 537         struct nfs_delegation *delegation;
 538         bool ret = false;
 539
 540         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 541                 nfs_mark_return_delegation(server, delegation);
 542                 ret = true;
 543         }
 544         return ret;
 545 }
 546
 547 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 548 {
 549         struct nfs_server *server;
 550
 551         rcu_read_lock();
 552         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 553                 nfs_server_mark_return_all_delegations(server);
 554         rcu_read_unlock();
 555 }
 556
 557 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 558 {
 559         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 560                 nfs4_schedule_state_manager(clp);
 561 }
 562
 563 /**
 564  * nfs_expire_all_delegations
 565  * @clp: client to process
 566  *
 567  */
 568 void nfs_expire_all_delegations(struct nfs_client *clp)
 569 {
 570         nfs_client_mark_return_all_delegations(clp);
 571         nfs_delegation_run_state_manager(clp);
 572 }
 573
 574 /**
 575  * nfs_super_return_all_delegations - return delegations for one superblock
 576  * @sb: sb to process
 577  *
 578  */
 579 void nfs_server_return_all_delegations(struct nfs_server *server)
 580 {
 581         struct nfs_client *clp = server->nfs_client;
 582         bool need_wait;
 583
 584         if (clp == NULL)
 585                 return;
 586
 587         rcu_read_lock();
 588         need_wait = nfs_server_mark_return_all_delegations(server);
 589         rcu_read_unlock();
 590
 591         if (need_wait) {
 592                 nfs4_schedule_state_manager(clp);
 593                 nfs4_wait_clnt_recover(clp);
 594         }
 595 }
 596
 597 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 598                                                  fmode_t flags)
 599 {
 600         struct nfs_delegation *delegation;
 601
 602         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 603                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 604                         continue;
 605                 if (delegation->type & flags)
 606                         nfs_mark_return_if_closed_delegation(server, delegation);
 607         }
 608 }
 609
 610 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 611                                                         fmode_t flags)
 612 {
 613         struct nfs_server *server;
 614
 615         rcu_read_lock();
 616         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 617                 nfs_mark_return_unused_delegation_types(server, flags);
 618         rcu_read_unlock();
 619 }
 620
 621 static void nfs_revoke_delegation(struct inode *inode)
 622 {
 623         struct nfs_delegation *delegation;
 624         rcu_read_lock();
 625         delegation = rcu_dereference(NFS_I(inode)->delegation);
 626         if (delegation != NULL) {
 627                 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 628                 nfs_mark_return_delegation(NFS_SERVER(inode), delegation);
 629         }
 630         rcu_read_unlock();
 631 }
 632
 633 void nfs_remove_bad_delegation(struct inode *inode)
 634 {
 635         struct nfs_delegation *delegation;
 636
 637         nfs_revoke_delegation(inode);
 638         delegation = nfs_inode_detach_delegation(inode);
 639         if (delegation) {
 640                 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
 641                 nfs_free_delegation(delegation);
 642         }
 643 }
 644 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 645
 646 /**
 647  * nfs_expire_unused_delegation_types
 648  * @clp: client to process
 649  * @flags: delegation types to expire
 650  *
 651  */
 652 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 653 {
 654         nfs_client_mark_return_unused_delegation_types(clp, flags);
 655         nfs_delegation_run_state_manager(clp);
 656 }
 657
 658 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 659 {
 660         struct nfs_delegation *delegation;
 661
 662         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 663                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 664                         continue;
 665                 nfs_mark_return_if_closed_delegation(server, delegation);
 666         }
 667 }
 668
 669 /**
 670  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 671  * @clp: nfs_client to process
 672  *
 673  */
 674 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 675 {
 676         struct nfs_server *server;
 677
 678         rcu_read_lock();
 679         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 680                 nfs_mark_return_unreferenced_delegations(server);
 681         rcu_read_unlock();
 682
 683         nfs_delegation_run_state_manager(clp);
 684 }
 685
 686 /**
 687  * nfs_async_inode_return_delegation - asynchronously return a delegation
 688  * @inode: inode to process
 689  * @stateid: state ID information
 690  *
 691  * Returns zero on success, or a negative errno value.
 692  */
 693 int nfs_async_inode_return_delegation(struct inode *inode,
 694                                       const nfs4_stateid *stateid)
 695 {
 696         struct nfs_server *server = NFS_SERVER(inode);
 697         struct nfs_client *clp = server->nfs_client;
 698         struct nfs_delegation *delegation;
 699
 700         filemap_flush(inode->i_mapping);
 701
 702         rcu_read_lock();
 703         delegation = rcu_dereference(NFS_I(inode)->delegation);
 704         if (delegation == NULL)
 705                 goto out_enoent;
 706
 707         if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 708                 goto out_enoent;
 709         nfs_mark_return_delegation(server, delegation);
 710         rcu_read_unlock();
 711
 712         nfs_delegation_run_state_manager(clp);
 713         return 0;
 714 out_enoent:
 715         rcu_read_unlock();
 716         return -ENOENT;
 717 }
 718
 719 static struct inode *
 720 nfs_delegation_find_inode_server(struct nfs_server *server,
 721                                  const struct nfs_fh *fhandle)
 722 {
 723         struct nfs_delegation *delegation;
 724         struct inode *res = NULL;
 725
 726         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 727                 spin_lock(&delegation->lock);
 728                 if (delegation->inode != NULL &&
 729                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 730                         res = igrab(delegation->inode);
 731                 }
 732                 spin_unlock(&delegation->lock);
 733                 if (res != NULL)
 734                         break;
 735         }
 736         return res;
 737 }
 738
 739 /**
 740  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 741  * @clp: client state handle
 742  * @fhandle: filehandle from a delegation recall
 743  *
 744  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 745  * cannot be found.
 746  */
 747 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 748                                         const struct nfs_fh *fhandle)
 749 {
 750         struct nfs_server *server;
 751         struct inode *res = NULL;
 752
 753         rcu_read_lock();
 754         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 755                 res = nfs_delegation_find_inode_server(server, fhandle);
 756                 if (res != NULL)
 757                         break;
 758         }
 759         rcu_read_unlock();
 760         return res;
 761 }
 762
 763 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 764 {
 765         struct nfs_delegation *delegation;
 766
 767         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
 768                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 769 }
 770
 771 /**
 772  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 773  * @clp: nfs_client to process
 774  *
 775  */
 776 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 777 {
 778         struct nfs_server *server;
 779
 780         rcu_read_lock();
 781         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 782                 nfs_delegation_mark_reclaim_server(server);
 783         rcu_read_unlock();
 784 }
 785
 786 /**
 787  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 788  * @clp: nfs_client to process
 789  *
 790  */
 791 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 792 {
 793         struct nfs_delegation *delegation;
 794         struct nfs_server *server;
 795         struct inode *inode;
 796
 797 restart:
 798         rcu_read_lock();
 799         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 800                 list_for_each_entry_rcu(delegation, &server->delegations,
 801                                                                 super_list) {
 802                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 803                                                 &delegation->flags) == 0)
 804                                 continue;
 805                         inode = nfs_delegation_grab_inode(delegation);
 806                         if (inode == NULL)
 807                                 continue;
 808                         delegation = nfs_detach_delegation(NFS_I(inode),
 809                                         delegation, server);
 810                         rcu_read_unlock();
 811
 812                         if (delegation != NULL)
 813                                 nfs_free_delegation(delegation);
 814                         iput(inode);
 815                         goto restart;
 816                 }
 817         }
 818         rcu_read_unlock();
 819 }
 820
 821 /**
 822  * nfs_delegations_present - check for existence of delegations
 823  * @clp: client state handle
 824  *
 825  * Returns one if there are any nfs_delegation structures attached
 826  * to this nfs_client.
 827  */
 828 int nfs_delegations_present(struct nfs_client *clp)
 829 {
 830         struct nfs_server *server;
 831         int ret = 0;
 832
 833         rcu_read_lock();
 834         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 835                 if (!list_empty(&server->delegations)) {
 836                         ret = 1;
 837                         break;
 838                 }
 839         rcu_read_unlock();
 840         return ret;
 841 }
 842
 843 /**
 844  * nfs4_copy_delegation_stateid - Copy inode's state ID information
 845  * @dst: stateid data structure to fill in
 846  * @inode: inode to check
 847  * @flags: delegation type requirement
 848  *
 849  * Returns "true" and fills in "dst->data" * if inode had a delegation,
 850  * otherwise "false" is returned.
 851  */
 852 bool nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode,
 853                 fmode_t flags)
 854 {
 855         struct nfs_inode *nfsi = NFS_I(inode);
 856         struct nfs_delegation *delegation;
 857         bool ret;
 858
 859         flags &= FMODE_READ|FMODE_WRITE;
 860         rcu_read_lock();
 861         delegation = rcu_dereference(nfsi->delegation);
 862         ret = (delegation != NULL && (delegation->type & flags) == flags);
 863         if (ret) {
 864                 nfs4_stateid_copy(dst, &delegation->stateid);
 865                 nfs_mark_delegation_referenced(delegation);
 866         }
 867         rcu_read_unlock();
 868         return ret;
 869 }