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