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