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 #include <linux/iversion.h>
  16
  17 #include <linux/nfs4.h>
  18 #include <linux/nfs_fs.h>
  19 #include <linux/nfs_xdr.h>
  20
  21 #include "nfs4_fs.h"
  22 #include "delegation.h"
  23 #include "internal.h"
  24 #include "nfs4trace.h"
  25
  26 static void nfs_free_delegation(struct nfs_delegation *delegation)
  27 {
  28         if (delegation->cred) {
  29                 put_rpccred(delegation->cred);
  30                 delegation->cred = NULL;
  31         }
  32         kfree_rcu(delegation, rcu);
  33 }
  34
  35 /**
  36  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
  37  * @delegation: delegation to process
  38  *
  39  */
  40 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  41 {
  42         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  43 }
  44
  45 static bool
  46 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
  47                 fmode_t flags)
  48 {
  49         if (delegation != NULL && (delegation->type & flags) == flags &&
  50             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
  51             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
  52                 return true;
  53         return false;
  54 }
  55
  56 static int
  57 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  58 {
  59         struct nfs_delegation *delegation;
  60         int ret = 0;
  61
  62         flags &= FMODE_READ|FMODE_WRITE;
  63         rcu_read_lock();
  64         delegation = rcu_dereference(NFS_I(inode)->delegation);
  65         if (nfs4_is_valid_delegation(delegation, flags)) {
  66                 if (mark)
  67                         nfs_mark_delegation_referenced(delegation);
  68                 ret = 1;
  69         }
  70         rcu_read_unlock();
  71         return ret;
  72 }
  73 /**
  74  * nfs_have_delegation - check if inode has a delegation, mark it
  75  * NFS_DELEGATION_REFERENCED if there is one.
  76  * @inode: inode to check
  77  * @flags: delegation types to check for
  78  *
  79  * Returns one if inode has the indicated delegation, otherwise zero.
  80  */
  81 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  82 {
  83         return nfs4_do_check_delegation(inode, flags, true);
  84 }
  85
  86 /*
  87  * nfs4_check_delegation - check if inode has a delegation, do not mark
  88  * NFS_DELEGATION_REFERENCED if it has one.
  89  */
  90 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
  91 {
  92         return nfs4_do_check_delegation(inode, flags, false);
  93 }
  94
  95 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
  96 {
  97         struct inode *inode = state->inode;
  98         struct file_lock *fl;
  99         struct file_lock_context *flctx = inode->i_flctx;
 100         struct list_head *list;
 101         int status = 0;
 102
 103         if (flctx == NULL)
 104                 goto out;
 105
 106         list = &flctx->flc_posix;
 107         spin_lock(&flctx->flc_lock);
 108 restart:
 109         list_for_each_entry(fl, list, fl_list) {
 110                 if (nfs_file_open_context(fl->fl_file) != ctx)
 111                         continue;
 112                 spin_unlock(&flctx->flc_lock);
 113                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 114                 if (status < 0)
 115                         goto out;
 116                 spin_lock(&flctx->flc_lock);
 117         }
 118         if (list == &flctx->flc_posix) {
 119                 list = &flctx->flc_flock;
 120                 goto restart;
 121         }
 122         spin_unlock(&flctx->flc_lock);
 123 out:
 124         return status;
 125 }
 126
 127 static int nfs_delegation_claim_opens(struct inode *inode,
 128                 const nfs4_stateid *stateid, fmode_t type)
 129 {
 130         struct nfs_inode *nfsi = NFS_I(inode);
 131         struct nfs_open_context *ctx;
 132         struct nfs4_state_owner *sp;
 133         struct nfs4_state *state;
 134         unsigned int seq;
 135         int err;
 136
 137 again:
 138         spin_lock(&inode->i_lock);
 139         list_for_each_entry(ctx, &nfsi->open_files, list) {
 140                 state = ctx->state;
 141                 if (state == NULL)
 142                         continue;
 143                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 144                         continue;
 145                 if (!nfs4_valid_open_stateid(state))
 146                         continue;
 147                 if (!nfs4_stateid_match(&state->stateid, stateid))
 148                         continue;
 149                 get_nfs_open_context(ctx);
 150                 spin_unlock(&inode->i_lock);
 151                 sp = state->owner;
 152                 /* Block nfs4_proc_unlck */
 153                 mutex_lock(&sp->so_delegreturn_mutex);
 154                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 155                 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
 156                 if (!err)
 157                         err = nfs_delegation_claim_locks(ctx, state, stateid);
 158                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 159                         err = -EAGAIN;
 160                 mutex_unlock(&sp->so_delegreturn_mutex);
 161                 put_nfs_open_context(ctx);
 162                 if (err != 0)
 163                         return err;
 164                 goto again;
 165         }
 166         spin_unlock(&inode->i_lock);
 167         return 0;
 168 }
 169
 170 /**
 171  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 172  * @inode: inode to process
 173  * @cred: credential to use for request
 174  * @res: new delegation state from server
 175  *
 176  */
 177 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
 178                                   struct nfs_openres *res)
 179 {
 180         struct nfs_delegation *delegation;
 181         struct rpc_cred *oldcred = NULL;
 182
 183         rcu_read_lock();
 184         delegation = rcu_dereference(NFS_I(inode)->delegation);
 185         if (delegation != NULL) {
 186                 spin_lock(&delegation->lock);
 187                 if (delegation->inode != NULL) {
 188                         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 189                         delegation->type = res->delegation_type;
 190                         delegation->pagemod_limit = res->pagemod_limit;
 191                         oldcred = delegation->cred;
 192                         delegation->cred = get_rpccred(cred);
 193                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 194                                   &delegation->flags);
 195                         spin_unlock(&delegation->lock);
 196                         rcu_read_unlock();
 197                         put_rpccred(oldcred);
 198                         trace_nfs4_reclaim_delegation(inode, res->delegation_type);
 199                         return;
 200                 }
 201                 /* We appear to have raced with a delegation return. */
 202                 spin_unlock(&delegation->lock);
 203         }
 204         rcu_read_unlock();
 205         nfs_inode_set_delegation(inode, cred, res);
 206 }
 207
 208 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 209 {
 210         int res = 0;
 211
 212         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 213                 res = nfs4_proc_delegreturn(inode,
 214                                 delegation->cred,
 215                                 &delegation->stateid,
 216                                 issync);
 217         nfs_free_delegation(delegation);
 218         return res;
 219 }
 220
 221 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 222 {
 223         struct inode *inode = NULL;
 224
 225         spin_lock(&delegation->lock);
 226         if (delegation->inode != NULL)
 227                 inode = igrab(delegation->inode);
 228         spin_unlock(&delegation->lock);
 229         return inode;
 230 }
 231
 232 static struct nfs_delegation *
 233 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 234 {
 235         struct nfs_delegation *ret = NULL;
 236         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 237
 238         if (delegation == NULL)
 239                 goto out;
 240         spin_lock(&delegation->lock);
 241         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 242                 ret = delegation;
 243         spin_unlock(&delegation->lock);
 244 out:
 245         return ret;
 246 }
 247
 248 static struct nfs_delegation *
 249 nfs_start_delegation_return(struct nfs_inode *nfsi)
 250 {
 251         struct nfs_delegation *delegation;
 252
 253         rcu_read_lock();
 254         delegation = nfs_start_delegation_return_locked(nfsi);
 255         rcu_read_unlock();
 256         return delegation;
 257 }
 258
 259 static void
 260 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 261                 struct nfs_client *clp)
 262 {
 263
 264         spin_lock(&delegation->lock);
 265         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 266         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 267         spin_unlock(&delegation->lock);
 268         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 269 }
 270
 271 static struct nfs_delegation *
 272 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 273                 struct nfs_delegation *delegation,
 274                 struct nfs_client *clp)
 275 {
 276         struct nfs_delegation *deleg_cur =
 277                 rcu_dereference_protected(nfsi->delegation,
 278                                 lockdep_is_held(&clp->cl_lock));
 279
 280         if (deleg_cur == NULL || delegation != deleg_cur)
 281                 return NULL;
 282
 283         spin_lock(&delegation->lock);
 284         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 285         list_del_rcu(&delegation->super_list);
 286         delegation->inode = NULL;
 287         rcu_assign_pointer(nfsi->delegation, NULL);
 288         spin_unlock(&delegation->lock);
 289         return delegation;
 290 }
 291
 292 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 293                 struct nfs_delegation *delegation,
 294                 struct nfs_server *server)
 295 {
 296         struct nfs_client *clp = server->nfs_client;
 297
 298         spin_lock(&clp->cl_lock);
 299         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 300         spin_unlock(&clp->cl_lock);
 301         return delegation;
 302 }
 303
 304 static struct nfs_delegation *
 305 nfs_inode_detach_delegation(struct inode *inode)
 306 {
 307         struct nfs_inode *nfsi = NFS_I(inode);
 308         struct nfs_server *server = NFS_SERVER(inode);
 309         struct nfs_delegation *delegation;
 310
 311         delegation = nfs_start_delegation_return(nfsi);
 312         if (delegation == NULL)
 313                 return NULL;
 314         return nfs_detach_delegation(nfsi, delegation, server);
 315 }
 316
 317 static void
 318 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 319                 const struct nfs_delegation *update)
 320 {
 321         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 322                 delegation->stateid.seqid = update->stateid.seqid;
 323                 smp_wmb();
 324                 delegation->type = update->type;
 325         }
 326 }
 327
 328 /**
 329  * nfs_inode_set_delegation - set up a delegation on an inode
 330  * @inode: inode to which delegation applies
 331  * @cred: cred to use for subsequent delegation processing
 332  * @res: new delegation state from server
 333  *
 334  * Returns zero on success, or a negative errno value.
 335  */
 336 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 337 {
 338         struct nfs_server *server = NFS_SERVER(inode);
 339         struct nfs_client *clp = server->nfs_client;
 340         struct nfs_inode *nfsi = NFS_I(inode);
 341         struct nfs_delegation *delegation, *old_delegation;
 342         struct nfs_delegation *freeme = NULL;
 343         int status = 0;
 344
 345         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 346         if (delegation == NULL)
 347                 return -ENOMEM;
 348         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 349         delegation->type = res->delegation_type;
 350         delegation->pagemod_limit = res->pagemod_limit;
 351         delegation->change_attr = inode_peek_iversion_raw(inode);
 352         delegation->cred = get_rpccred(cred);
 353         delegation->inode = inode;
 354         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 355         spin_lock_init(&delegation->lock);
 356
 357         spin_lock(&clp->cl_lock);
 358         old_delegation = rcu_dereference_protected(nfsi->delegation,
 359                                         lockdep_is_held(&clp->cl_lock));
 360         if (old_delegation != NULL) {
 361                 /* Is this an update of the existing delegation? */
 362                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 363                                         &delegation->stateid)) {
 364                         nfs_update_inplace_delegation(old_delegation,
 365                                         delegation);
 366                         goto out;
 367                 }
 368                 /*
 369                  * Deal with broken servers that hand out two
 370                  * delegations for the same file.
 371                  * Allow for upgrades to a WRITE delegation, but
 372                  * nothing else.
 373                  */
 374                 dfprintk(FILE, "%s: server %s handed out "
 375                                 "a duplicate delegation!\n",
 376                                 __func__, clp->cl_hostname);
 377                 if (delegation->type == old_delegation->type ||
 378                     !(delegation->type & FMODE_WRITE)) {
 379                         freeme = delegation;
 380                         delegation = NULL;
 381                         goto out;
 382                 }
 383                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 384                                         &old_delegation->flags))
 385                         goto out;
 386                 freeme = nfs_detach_delegation_locked(nfsi,
 387                                 old_delegation, clp);
 388                 if (freeme == NULL)
 389                         goto out;
 390         }
 391         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 392         rcu_assign_pointer(nfsi->delegation, delegation);
 393         delegation = NULL;
 394
 395         trace_nfs4_set_delegation(inode, res->delegation_type);
 396
 397 out:
 398         spin_unlock(&clp->cl_lock);
 399         if (delegation != NULL)
 400                 nfs_free_delegation(delegation);
 401         if (freeme != NULL)
 402                 nfs_do_return_delegation(inode, freeme, 0);
 403         return status;
 404 }
 405
 406 /*
 407  * Basic procedure for returning a delegation to the server
 408  */
 409 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 410 {
 411         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 412         struct nfs_inode *nfsi = NFS_I(inode);
 413         int err = 0;
 414
 415         if (delegation == NULL)
 416                 return 0;
 417         do {
 418                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 419                         break;
 420                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 421                                 delegation->type);
 422                 if (!issync || err != -EAGAIN)
 423                         break;
 424                 /*
 425                  * Guard against state recovery
 426                  */
 427                 err = nfs4_wait_clnt_recover(clp);
 428         } while (err == 0);
 429
 430         if (err) {
 431                 nfs_abort_delegation_return(delegation, clp);
 432                 goto out;
 433         }
 434         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 435                 goto out;
 436
 437         err = nfs_do_return_delegation(inode, delegation, issync);
 438 out:
 439         return err;
 440 }
 441
 442 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 443 {
 444         bool ret = false;
 445
 446         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 447                 goto out;
 448         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 449                 ret = true;
 450         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 451                 struct inode *inode;
 452
 453                 spin_lock(&delegation->lock);
 454                 inode = delegation->inode;
 455                 if (inode && list_empty(&NFS_I(inode)->open_files))
 456                         ret = true;
 457                 spin_unlock(&delegation->lock);
 458         }
 459 out:
 460         return ret;
 461 }
 462
 463 /**
 464  * nfs_client_return_marked_delegations - return previously marked delegations
 465  * @clp: nfs_client to process
 466  *
 467  * Note that this function is designed to be called by the state
 468  * manager thread. For this reason, it cannot flush the dirty data,
 469  * since that could deadlock in case of a state recovery error.
 470  *
 471  * Returns zero on success, or a negative errno value.
 472  */
 473 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 474 {
 475         struct nfs_delegation *delegation;
 476         struct nfs_server *server;
 477         struct inode *inode;
 478         int err = 0;
 479
 480 restart:
 481         rcu_read_lock();
 482         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 483                 list_for_each_entry_rcu(delegation, &server->delegations,
 484                                                                 super_list) {
 485                         if (!nfs_delegation_need_return(delegation))
 486                                 continue;
 487                         if (!nfs_sb_active(server->super))
 488                                 continue;
 489                         inode = nfs_delegation_grab_inode(delegation);
 490                         if (inode == NULL) {
 491                                 rcu_read_unlock();
 492                                 nfs_sb_deactive(server->super);
 493                                 goto restart;
 494                         }
 495                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 496                         rcu_read_unlock();
 497
 498                         err = nfs_end_delegation_return(inode, delegation, 0);
 499                         iput(inode);
 500                         nfs_sb_deactive(server->super);
 501                         if (!err)
 502                                 goto restart;
 503                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 504                         return err;
 505                 }
 506         }
 507         rcu_read_unlock();
 508         return 0;
 509 }
 510
 511 /**
 512  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 513  * @inode: inode to process
 514  *
 515  * Does not protect against delegation reclaims, therefore really only safe
 516  * to be called from nfs4_clear_inode().
 517  */
 518 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 519 {
 520         struct nfs_delegation *delegation;
 521
 522         delegation = nfs_inode_detach_delegation(inode);
 523         if (delegation != NULL)
 524                 nfs_do_return_delegation(inode, delegation, 1);
 525 }
 526
 527 /**
 528  * nfs_inode_return_delegation - synchronously return a delegation
 529  * @inode: inode to process
 530  *
 531  * This routine will always flush any dirty data to disk on the
 532  * assumption that if we need to return the delegation, then
 533  * we should stop caching.
 534  *
 535  * Returns zero on success, or a negative errno value.
 536  */
 537 int nfs4_inode_return_delegation(struct inode *inode)
 538 {
 539         struct nfs_inode *nfsi = NFS_I(inode);
 540         struct nfs_delegation *delegation;
 541         int err = 0;
 542
 543         nfs_wb_all(inode);
 544         delegation = nfs_start_delegation_return(nfsi);
 545         if (delegation != NULL)
 546                 err = nfs_end_delegation_return(inode, delegation, 1);
 547         return err;
 548 }
 549
 550 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 551                 struct nfs_delegation *delegation)
 552 {
 553         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 554         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 555 }
 556
 557 static void nfs_mark_return_delegation(struct nfs_server *server,
 558                 struct nfs_delegation *delegation)
 559 {
 560         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 561         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 562 }
 563
 564 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 565 {
 566         struct nfs_delegation *delegation;
 567         bool ret = false;
 568
 569         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 570                 nfs_mark_return_delegation(server, delegation);
 571                 ret = true;
 572         }
 573         return ret;
 574 }
 575
 576 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 577 {
 578         struct nfs_server *server;
 579
 580         rcu_read_lock();
 581         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 582                 nfs_server_mark_return_all_delegations(server);
 583         rcu_read_unlock();
 584 }
 585
 586 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 587 {
 588         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 589                 nfs4_schedule_state_manager(clp);
 590 }
 591
 592 /**
 593  * nfs_expire_all_delegations
 594  * @clp: client to process
 595  *
 596  */
 597 void nfs_expire_all_delegations(struct nfs_client *clp)
 598 {
 599         nfs_client_mark_return_all_delegations(clp);
 600         nfs_delegation_run_state_manager(clp);
 601 }
 602
 603 /**
 604  * nfs_super_return_all_delegations - return delegations for one superblock
 605  * @sb: sb to process
 606  *
 607  */
 608 void nfs_server_return_all_delegations(struct nfs_server *server)
 609 {
 610         struct nfs_client *clp = server->nfs_client;
 611         bool need_wait;
 612
 613         if (clp == NULL)
 614                 return;
 615
 616         rcu_read_lock();
 617         need_wait = nfs_server_mark_return_all_delegations(server);
 618         rcu_read_unlock();
 619
 620         if (need_wait) {
 621                 nfs4_schedule_state_manager(clp);
 622                 nfs4_wait_clnt_recover(clp);
 623         }
 624 }
 625
 626 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 627                                                  fmode_t flags)
 628 {
 629         struct nfs_delegation *delegation;
 630
 631         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 632                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 633                         continue;
 634                 if (delegation->type & flags)
 635                         nfs_mark_return_if_closed_delegation(server, delegation);
 636         }
 637 }
 638
 639 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 640                                                         fmode_t flags)
 641 {
 642         struct nfs_server *server;
 643
 644         rcu_read_lock();
 645         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 646                 nfs_mark_return_unused_delegation_types(server, flags);
 647         rcu_read_unlock();
 648 }
 649
 650 static void nfs_mark_delegation_revoked(struct nfs_server *server,
 651                 struct nfs_delegation *delegation)
 652 {
 653         set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 654         delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
 655         nfs_mark_return_delegation(server, delegation);
 656 }
 657
 658 static bool nfs_revoke_delegation(struct inode *inode,
 659                 const nfs4_stateid *stateid)
 660 {
 661         struct nfs_delegation *delegation;
 662         nfs4_stateid tmp;
 663         bool ret = false;
 664
 665         rcu_read_lock();
 666         delegation = rcu_dereference(NFS_I(inode)->delegation);
 667         if (delegation == NULL)
 668                 goto out;
 669         if (stateid == NULL) {
 670                 nfs4_stateid_copy(&tmp, &delegation->stateid);
 671                 stateid = &tmp;
 672         } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
 673                 goto out;
 674         nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
 675         ret = true;
 676 out:
 677         rcu_read_unlock();
 678         if (ret)
 679                 nfs_inode_find_state_and_recover(inode, stateid);
 680         return ret;
 681 }
 682
 683 void nfs_remove_bad_delegation(struct inode *inode,
 684                 const nfs4_stateid *stateid)
 685 {
 686         struct nfs_delegation *delegation;
 687
 688         if (!nfs_revoke_delegation(inode, stateid))
 689                 return;
 690         delegation = nfs_inode_detach_delegation(inode);
 691         if (delegation)
 692                 nfs_free_delegation(delegation);
 693 }
 694 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 695
 696 /**
 697  * nfs_expire_unused_delegation_types
 698  * @clp: client to process
 699  * @flags: delegation types to expire
 700  *
 701  */
 702 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 703 {
 704         nfs_client_mark_return_unused_delegation_types(clp, flags);
 705         nfs_delegation_run_state_manager(clp);
 706 }
 707
 708 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 709 {
 710         struct nfs_delegation *delegation;
 711
 712         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 713                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 714                         continue;
 715                 nfs_mark_return_if_closed_delegation(server, delegation);
 716         }
 717 }
 718
 719 /**
 720  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 721  * @clp: nfs_client to process
 722  *
 723  */
 724 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 725 {
 726         struct nfs_server *server;
 727
 728         rcu_read_lock();
 729         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 730                 nfs_mark_return_unreferenced_delegations(server);
 731         rcu_read_unlock();
 732
 733         nfs_delegation_run_state_manager(clp);
 734 }
 735
 736 /**
 737  * nfs_async_inode_return_delegation - asynchronously return a delegation
 738  * @inode: inode to process
 739  * @stateid: state ID information
 740  *
 741  * Returns zero on success, or a negative errno value.
 742  */
 743 int nfs_async_inode_return_delegation(struct inode *inode,
 744                                       const nfs4_stateid *stateid)
 745 {
 746         struct nfs_server *server = NFS_SERVER(inode);
 747         struct nfs_client *clp = server->nfs_client;
 748         struct nfs_delegation *delegation;
 749
 750         rcu_read_lock();
 751         delegation = rcu_dereference(NFS_I(inode)->delegation);
 752         if (delegation == NULL)
 753                 goto out_enoent;
 754         if (stateid != NULL &&
 755             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 756                 goto out_enoent;
 757         nfs_mark_return_delegation(server, delegation);
 758         rcu_read_unlock();
 759
 760         nfs_delegation_run_state_manager(clp);
 761         return 0;
 762 out_enoent:
 763         rcu_read_unlock();
 764         return -ENOENT;
 765 }
 766
 767 static struct inode *
 768 nfs_delegation_find_inode_server(struct nfs_server *server,
 769                                  const struct nfs_fh *fhandle)
 770 {
 771         struct nfs_delegation *delegation;
 772         struct inode *res = NULL;
 773
 774         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 775                 spin_lock(&delegation->lock);
 776                 if (delegation->inode != NULL &&
 777                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 778                         res = igrab(delegation->inode);
 779                 }
 780                 spin_unlock(&delegation->lock);
 781                 if (res != NULL)
 782                         break;
 783         }
 784         return res;
 785 }
 786
 787 /**
 788  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 789  * @clp: client state handle
 790  * @fhandle: filehandle from a delegation recall
 791  *
 792  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 793  * cannot be found.
 794  */
 795 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 796                                         const struct nfs_fh *fhandle)
 797 {
 798         struct nfs_server *server;
 799         struct inode *res = NULL;
 800
 801         rcu_read_lock();
 802         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 803                 res = nfs_delegation_find_inode_server(server, fhandle);
 804                 if (res != NULL)
 805                         break;
 806         }
 807         rcu_read_unlock();
 808         return res;
 809 }
 810
 811 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 812 {
 813         struct nfs_delegation *delegation;
 814
 815         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 816                 /*
 817                  * If the delegation may have been admin revoked, then we
 818                  * cannot reclaim it.
 819                  */
 820                 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
 821                         continue;
 822                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 823         }
 824 }
 825
 826 /**
 827  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 828  * @clp: nfs_client to process
 829  *
 830  */
 831 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 832 {
 833         struct nfs_server *server;
 834
 835         rcu_read_lock();
 836         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 837                 nfs_delegation_mark_reclaim_server(server);
 838         rcu_read_unlock();
 839 }
 840
 841 /**
 842  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 843  * @clp: nfs_client to process
 844  *
 845  */
 846 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 847 {
 848         struct nfs_delegation *delegation;
 849         struct nfs_server *server;
 850         struct inode *inode;
 851
 852 restart:
 853         rcu_read_lock();
 854         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 855                 list_for_each_entry_rcu(delegation, &server->delegations,
 856                                                                 super_list) {
 857                         if (test_bit(NFS_DELEGATION_RETURNING,
 858                                                 &delegation->flags))
 859                                 continue;
 860                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 861                                                 &delegation->flags) == 0)
 862                                 continue;
 863                         if (!nfs_sb_active(server->super))
 864                                 continue;
 865                         inode = nfs_delegation_grab_inode(delegation);
 866                         if (inode == NULL) {
 867                                 rcu_read_unlock();
 868                                 nfs_sb_deactive(server->super);
 869                                 goto restart;
 870                         }
 871                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 872                         rcu_read_unlock();
 873                         if (delegation != NULL) {
 874                                 delegation = nfs_detach_delegation(NFS_I(inode),
 875                                         delegation, server);
 876                                 if (delegation != NULL)
 877                                         nfs_free_delegation(delegation);
 878                         }
 879                         iput(inode);
 880                         nfs_sb_deactive(server->super);
 881                         goto restart;
 882                 }
 883         }
 884         rcu_read_unlock();
 885 }
 886
 887 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
 888 {
 889         return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
 890                                 BIT(NFS4CLNT_LEASE_EXPIRED) |
 891                                 BIT(NFS4CLNT_SESSION_RESET))) != 0;
 892 }
 893
 894 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
 895             struct nfs_delegation *delegation)
 896 {
 897         if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
 898                 return;
 899         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 900         set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 901         set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
 902 }
 903
 904 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
 905                 struct inode *inode)
 906 {
 907         struct nfs_delegation *delegation;
 908
 909         rcu_read_lock();
 910         delegation = rcu_dereference(NFS_I(inode)->delegation);
 911         if (delegation)
 912                 nfs_mark_test_expired_delegation(server, delegation);
 913         rcu_read_unlock();
 914
 915 }
 916
 917 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
 918 {
 919         struct nfs_delegation *delegation;
 920
 921         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
 922                 nfs_mark_test_expired_delegation(server, delegation);
 923 }
 924
 925 /**
 926  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
 927  * @clp: nfs_client to process
 928  *
 929  * Iterates through all the delegations associated with this server and
 930  * marks them as needing to be checked for validity.
 931  */
 932 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
 933 {
 934         struct nfs_server *server;
 935
 936         rcu_read_lock();
 937         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 938                 nfs_delegation_mark_test_expired_server(server);
 939         rcu_read_unlock();
 940 }
 941
 942 /**
 943  * nfs_reap_expired_delegations - reap expired delegations
 944  * @clp: nfs_client to process
 945  *
 946  * Iterates through all the delegations associated with this server and
 947  * checks if they have may have been revoked. This function is usually
 948  * expected to be called in cases where the server may have lost its
 949  * lease.
 950  */
 951 void nfs_reap_expired_delegations(struct nfs_client *clp)
 952 {
 953         const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
 954         struct nfs_delegation *delegation;
 955         struct nfs_server *server;
 956         struct inode *inode;
 957         struct rpc_cred *cred;
 958         nfs4_stateid stateid;
 959
 960 restart:
 961         rcu_read_lock();
 962         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 963                 list_for_each_entry_rcu(delegation, &server->delegations,
 964                                                                 super_list) {
 965                         if (test_bit(NFS_DELEGATION_RETURNING,
 966                                                 &delegation->flags))
 967                                 continue;
 968                         if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
 969                                                 &delegation->flags) == 0)
 970                                 continue;
 971                         if (!nfs_sb_active(server->super))
 972                                 continue;
 973                         inode = nfs_delegation_grab_inode(delegation);
 974                         if (inode == NULL) {
 975                                 rcu_read_unlock();
 976                                 nfs_sb_deactive(server->super);
 977                                 goto restart;
 978                         }
 979                         cred = get_rpccred_rcu(delegation->cred);
 980                         nfs4_stateid_copy(&stateid, &delegation->stateid);
 981                         clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 982                         rcu_read_unlock();
 983                         if (cred != NULL &&
 984                             ops->test_and_free_expired(server, &stateid, cred) < 0) {
 985                                 nfs_revoke_delegation(inode, &stateid);
 986                                 nfs_inode_find_state_and_recover(inode, &stateid);
 987                         }
 988                         put_rpccred(cred);
 989                         if (nfs4_server_rebooted(clp)) {
 990                                 nfs_inode_mark_test_expired_delegation(server,inode);
 991                                 iput(inode);
 992                                 nfs_sb_deactive(server->super);
 993                                 return;
 994                         }
 995                         iput(inode);
 996                         nfs_sb_deactive(server->super);
 997                         goto restart;
 998                 }
 999         }
1000         rcu_read_unlock();
1001 }
1002
1003 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1004                 const nfs4_stateid *stateid)
1005 {
1006         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1007         struct nfs_delegation *delegation;
1008         bool found = false;
1009
1010         rcu_read_lock();
1011         delegation = rcu_dereference(NFS_I(inode)->delegation);
1012         if (delegation &&
1013             nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1014                 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1015                 found = true;
1016         }
1017         rcu_read_unlock();
1018         if (found)
1019                 nfs4_schedule_state_manager(clp);
1020 }
1021
1022 /**
1023  * nfs_delegations_present - check for existence of delegations
1024  * @clp: client state handle
1025  *
1026  * Returns one if there are any nfs_delegation structures attached
1027  * to this nfs_client.
1028  */
1029 int nfs_delegations_present(struct nfs_client *clp)
1030 {
1031         struct nfs_server *server;
1032         int ret = 0;
1033
1034         rcu_read_lock();
1035         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1036                 if (!list_empty(&server->delegations)) {
1037                         ret = 1;
1038                         break;
1039                 }
1040         rcu_read_unlock();
1041         return ret;
1042 }
1043
1044 /**
1045  * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1046  * @dst: stateid to refresh
1047  * @inode: inode to check
1048  *
1049  * Returns "true" and updates "dst->seqid" * if inode had a delegation
1050  * that matches our delegation stateid. Otherwise "false" is returned.
1051  */
1052 bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1053 {
1054         struct nfs_delegation *delegation;
1055         bool ret = false;
1056         if (!inode)
1057                 goto out;
1058
1059         rcu_read_lock();
1060         delegation = rcu_dereference(NFS_I(inode)->delegation);
1061         if (delegation != NULL &&
1062             nfs4_stateid_match_other(dst, &delegation->stateid)) {
1063                 dst->seqid = delegation->stateid.seqid;
1064                 return ret;
1065         }
1066         rcu_read_unlock();
1067 out:
1068         return ret;
1069 }
1070
1071 /**
1072  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1073  * @inode: inode to check
1074  * @flags: delegation type requirement
1075  * @dst: stateid data structure to fill in
1076  * @cred: optional argument to retrieve credential
1077  *
1078  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1079  * otherwise "false" is returned.
1080  */
1081 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1082                 nfs4_stateid *dst, struct rpc_cred **cred)
1083 {
1084         struct nfs_inode *nfsi = NFS_I(inode);
1085         struct nfs_delegation *delegation;
1086         bool ret;
1087
1088         flags &= FMODE_READ|FMODE_WRITE;
1089         rcu_read_lock();
1090         delegation = rcu_dereference(nfsi->delegation);
1091         ret = nfs4_is_valid_delegation(delegation, flags);
1092         if (ret) {
1093                 nfs4_stateid_copy(dst, &delegation->stateid);
1094                 nfs_mark_delegation_referenced(delegation);
1095                 if (cred)
1096                         *cred = get_rpccred(delegation->cred);
1097         }
1098         rcu_read_unlock();
1099         return ret;
1100 }
1101
1102 /**
1103  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1104  * @inode: inode to check
1105  *
1106  * This function checks the number of outstanding writes to the file
1107  * against the delegation 'space_limit' field to see if
1108  * the spec requires us to flush the file on close.
1109  */
1110 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1111 {
1112         struct nfs_inode *nfsi = NFS_I(inode);
1113         struct nfs_delegation *delegation;
1114         bool ret = true;
1115
1116         rcu_read_lock();
1117         delegation = rcu_dereference(nfsi->delegation);
1118         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1119                 goto out;
1120         if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1121                 ret = false;
1122 out:
1123         rcu_read_unlock();
1124         return ret;
1125 }