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 "nfs4session.h"
  23 #include "delegation.h"
  24 #include "internal.h"
  25 #include "nfs4trace.h"
  26
  27 static void nfs_free_delegation(struct nfs_delegation *delegation)
  28 {
  29         put_cred(delegation->cred);
  30         delegation->cred = NULL;
  31         kfree_rcu(delegation, rcu);
  32 }
  33
  34 /**
  35  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
  36  * @delegation: delegation to process
  37  *
  38  */
  39 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  40 {
  41         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  42 }
  43
  44 static bool
  45 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
  46                 fmode_t flags)
  47 {
  48         if (delegation != NULL && (delegation->type & flags) == flags &&
  49             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
  50             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
  51                 return true;
  52         return false;
  53 }
  54
  55 static int
  56 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  57 {
  58         struct nfs_delegation *delegation;
  59         int ret = 0;
  60
  61         flags &= FMODE_READ|FMODE_WRITE;
  62         rcu_read_lock();
  63         delegation = rcu_dereference(NFS_I(inode)->delegation);
  64         if (nfs4_is_valid_delegation(delegation, flags)) {
  65                 if (mark)
  66                         nfs_mark_delegation_referenced(delegation);
  67                 ret = 1;
  68         }
  69         rcu_read_unlock();
  70         return ret;
  71 }
  72 /**
  73  * nfs_have_delegation - check if inode has a delegation, mark it
  74  * NFS_DELEGATION_REFERENCED if there is one.
  75  * @inode: inode to check
  76  * @flags: delegation types to check for
  77  *
  78  * Returns one if inode has the indicated delegation, otherwise zero.
  79  */
  80 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  81 {
  82         return nfs4_do_check_delegation(inode, flags, true);
  83 }
  84
  85 /*
  86  * nfs4_check_delegation - check if inode has a delegation, do not mark
  87  * NFS_DELEGATION_REFERENCED if it has one.
  88  */
  89 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
  90 {
  91         return nfs4_do_check_delegation(inode, flags, false);
  92 }
  93
  94 static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
  95 {
  96         struct inode *inode = state->inode;
  97         struct file_lock *fl;
  98         struct file_lock_context *flctx = inode->i_flctx;
  99         struct list_head *list;
 100         int status = 0;
 101
 102         if (flctx == NULL)
 103                 goto out;
 104
 105         list = &flctx->flc_posix;
 106         spin_lock(&flctx->flc_lock);
 107 restart:
 108         list_for_each_entry(fl, list, fl_list) {
 109                 if (nfs_file_open_context(fl->fl_file)->state != state)
 110                         continue;
 111                 spin_unlock(&flctx->flc_lock);
 112                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 113                 if (status < 0)
 114                         goto out;
 115                 spin_lock(&flctx->flc_lock);
 116         }
 117         if (list == &flctx->flc_posix) {
 118                 list = &flctx->flc_flock;
 119                 goto restart;
 120         }
 121         spin_unlock(&flctx->flc_lock);
 122 out:
 123         return status;
 124 }
 125
 126 static int nfs_delegation_claim_opens(struct inode *inode,
 127                 const nfs4_stateid *stateid, fmode_t type)
 128 {
 129         struct nfs_inode *nfsi = NFS_I(inode);
 130         struct nfs_open_context *ctx;
 131         struct nfs4_state_owner *sp;
 132         struct nfs4_state *state;
 133         unsigned int seq;
 134         int err;
 135
 136 again:
 137         rcu_read_lock();
 138         list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
 139                 state = ctx->state;
 140                 if (state == NULL)
 141                         continue;
 142                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 143                         continue;
 144                 if (!nfs4_valid_open_stateid(state))
 145                         continue;
 146                 if (!nfs4_stateid_match(&state->stateid, stateid))
 147                         continue;
 148                 if (!get_nfs_open_context(ctx))
 149                         continue;
 150                 rcu_read_unlock();
 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(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         rcu_read_unlock();
 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  * @type: delegation type
 175  * @stateid: delegation stateid
 176  * @pagemod_limit: write delegation "space_limit"
 177  *
 178  */
 179 void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
 180                                   fmode_t type,
 181                                   const nfs4_stateid *stateid,
 182                                   unsigned long pagemod_limit)
 183 {
 184         struct nfs_delegation *delegation;
 185         const struct cred *oldcred = NULL;
 186
 187         rcu_read_lock();
 188         delegation = rcu_dereference(NFS_I(inode)->delegation);
 189         if (delegation != NULL) {
 190                 spin_lock(&delegation->lock);
 191                 if (delegation->inode != NULL) {
 192                         nfs4_stateid_copy(&delegation->stateid, stateid);
 193                         delegation->type = type;
 194                         delegation->pagemod_limit = pagemod_limit;
 195                         oldcred = delegation->cred;
 196                         delegation->cred = get_cred(cred);
 197                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 198                                   &delegation->flags);
 199                         spin_unlock(&delegation->lock);
 200                         rcu_read_unlock();
 201                         put_cred(oldcred);
 202                         trace_nfs4_reclaim_delegation(inode, type);
 203                         return;
 204                 }
 205                 /* We appear to have raced with a delegation return. */
 206                 spin_unlock(&delegation->lock);
 207         }
 208         rcu_read_unlock();
 209         nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
 210 }
 211
 212 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 213 {
 214         int res = 0;
 215
 216         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 217                 res = nfs4_proc_delegreturn(inode,
 218                                 delegation->cred,
 219                                 &delegation->stateid,
 220                                 issync);
 221         nfs_free_delegation(delegation);
 222         return res;
 223 }
 224
 225 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 226 {
 227         struct inode *inode = NULL;
 228
 229         spin_lock(&delegation->lock);
 230         if (delegation->inode != NULL)
 231                 inode = igrab(delegation->inode);
 232         spin_unlock(&delegation->lock);
 233         return inode;
 234 }
 235
 236 static struct nfs_delegation *
 237 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 238 {
 239         struct nfs_delegation *ret = NULL;
 240         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 241
 242         if (delegation == NULL)
 243                 goto out;
 244         spin_lock(&delegation->lock);
 245         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 246                 ret = delegation;
 247         spin_unlock(&delegation->lock);
 248 out:
 249         return ret;
 250 }
 251
 252 static struct nfs_delegation *
 253 nfs_start_delegation_return(struct nfs_inode *nfsi)
 254 {
 255         struct nfs_delegation *delegation;
 256
 257         rcu_read_lock();
 258         delegation = nfs_start_delegation_return_locked(nfsi);
 259         rcu_read_unlock();
 260         return delegation;
 261 }
 262
 263 static void
 264 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 265                 struct nfs_client *clp)
 266 {
 267
 268         spin_lock(&delegation->lock);
 269         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 270         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 271         spin_unlock(&delegation->lock);
 272         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 273 }
 274
 275 static struct nfs_delegation *
 276 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 277                 struct nfs_delegation *delegation,
 278                 struct nfs_client *clp)
 279 {
 280         struct nfs_delegation *deleg_cur =
 281                 rcu_dereference_protected(nfsi->delegation,
 282                                 lockdep_is_held(&clp->cl_lock));
 283
 284         if (deleg_cur == NULL || delegation != deleg_cur)
 285                 return NULL;
 286
 287         spin_lock(&delegation->lock);
 288         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 289         list_del_rcu(&delegation->super_list);
 290         delegation->inode = NULL;
 291         rcu_assign_pointer(nfsi->delegation, NULL);
 292         spin_unlock(&delegation->lock);
 293         return delegation;
 294 }
 295
 296 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 297                 struct nfs_delegation *delegation,
 298                 struct nfs_server *server)
 299 {
 300         struct nfs_client *clp = server->nfs_client;
 301
 302         spin_lock(&clp->cl_lock);
 303         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 304         spin_unlock(&clp->cl_lock);
 305         return delegation;
 306 }
 307
 308 static struct nfs_delegation *
 309 nfs_inode_detach_delegation(struct inode *inode)
 310 {
 311         struct nfs_inode *nfsi = NFS_I(inode);
 312         struct nfs_server *server = NFS_SERVER(inode);
 313         struct nfs_delegation *delegation;
 314
 315         delegation = nfs_start_delegation_return(nfsi);
 316         if (delegation == NULL)
 317                 return NULL;
 318         return nfs_detach_delegation(nfsi, delegation, server);
 319 }
 320
 321 static void
 322 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 323                 const struct nfs_delegation *update)
 324 {
 325         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 326                 delegation->stateid.seqid = update->stateid.seqid;
 327                 smp_wmb();
 328                 delegation->type = update->type;
 329         }
 330 }
 331
 332 /**
 333  * nfs_inode_set_delegation - set up a delegation on an inode
 334  * @inode: inode to which delegation applies
 335  * @cred: cred to use for subsequent delegation processing
 336  * @type: delegation type
 337  * @stateid: delegation stateid
 338  * @pagemod_limit: write delegation "space_limit"
 339  *
 340  * Returns zero on success, or a negative errno value.
 341  */
 342 int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
 343                                   fmode_t type,
 344                                   const nfs4_stateid *stateid,
 345                                   unsigned long pagemod_limit)
 346 {
 347         struct nfs_server *server = NFS_SERVER(inode);
 348         struct nfs_client *clp = server->nfs_client;
 349         struct nfs_inode *nfsi = NFS_I(inode);
 350         struct nfs_delegation *delegation, *old_delegation;
 351         struct nfs_delegation *freeme = NULL;
 352         int status = 0;
 353
 354         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 355         if (delegation == NULL)
 356                 return -ENOMEM;
 357         nfs4_stateid_copy(&delegation->stateid, stateid);
 358         delegation->type = type;
 359         delegation->pagemod_limit = pagemod_limit;
 360         delegation->change_attr = inode_peek_iversion_raw(inode);
 361         delegation->cred = get_cred(cred);
 362         delegation->inode = inode;
 363         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 364         spin_lock_init(&delegation->lock);
 365
 366         spin_lock(&clp->cl_lock);
 367         old_delegation = rcu_dereference_protected(nfsi->delegation,
 368                                         lockdep_is_held(&clp->cl_lock));
 369         if (old_delegation != NULL) {
 370                 /* Is this an update of the existing delegation? */
 371                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 372                                         &delegation->stateid)) {
 373                         nfs_update_inplace_delegation(old_delegation,
 374                                         delegation);
 375                         goto out;
 376                 }
 377                 /*
 378                  * Deal with broken servers that hand out two
 379                  * delegations for the same file.
 380                  * Allow for upgrades to a WRITE delegation, but
 381                  * nothing else.
 382                  */
 383                 dfprintk(FILE, "%s: server %s handed out "
 384                                 "a duplicate delegation!\n",
 385                                 __func__, clp->cl_hostname);
 386                 if (delegation->type == old_delegation->type ||
 387                     !(delegation->type & FMODE_WRITE)) {
 388                         freeme = delegation;
 389                         delegation = NULL;
 390                         goto out;
 391                 }
 392                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 393                                         &old_delegation->flags))
 394                         goto out;
 395                 freeme = nfs_detach_delegation_locked(nfsi,
 396                                 old_delegation, clp);
 397                 if (freeme == NULL)
 398                         goto out;
 399         }
 400         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 401         rcu_assign_pointer(nfsi->delegation, delegation);
 402         delegation = NULL;
 403
 404         trace_nfs4_set_delegation(inode, type);
 405
 406         spin_lock(&inode->i_lock);
 407         if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME))
 408                 NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED;
 409         spin_unlock(&inode->i_lock);
 410 out:
 411         spin_unlock(&clp->cl_lock);
 412         if (delegation != NULL)
 413                 nfs_free_delegation(delegation);
 414         if (freeme != NULL)
 415                 nfs_do_return_delegation(inode, freeme, 0);
 416         return status;
 417 }
 418
 419 /*
 420  * Basic procedure for returning a delegation to the server
 421  */
 422 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 423 {
 424         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 425         struct nfs_inode *nfsi = NFS_I(inode);
 426         int err = 0;
 427
 428         if (delegation == NULL)
 429                 return 0;
 430         do {
 431                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 432                         break;
 433                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 434                                 delegation->type);
 435                 if (!issync || err != -EAGAIN)
 436                         break;
 437                 /*
 438                  * Guard against state recovery
 439                  */
 440                 err = nfs4_wait_clnt_recover(clp);
 441         } while (err == 0);
 442
 443         if (err) {
 444                 nfs_abort_delegation_return(delegation, clp);
 445                 goto out;
 446         }
 447         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 448                 goto out;
 449
 450         err = nfs_do_return_delegation(inode, delegation, issync);
 451 out:
 452         return err;
 453 }
 454
 455 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 456 {
 457         bool ret = false;
 458
 459         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 460                 goto out;
 461         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 462                 ret = true;
 463         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 464                 struct inode *inode;
 465
 466                 spin_lock(&delegation->lock);
 467                 inode = delegation->inode;
 468                 if (inode && list_empty(&NFS_I(inode)->open_files))
 469                         ret = true;
 470                 spin_unlock(&delegation->lock);
 471         }
 472 out:
 473         return ret;
 474 }
 475
 476 /**
 477  * nfs_client_return_marked_delegations - return previously marked delegations
 478  * @clp: nfs_client to process
 479  *
 480  * Note that this function is designed to be called by the state
 481  * manager thread. For this reason, it cannot flush the dirty data,
 482  * since that could deadlock in case of a state recovery error.
 483  *
 484  * Returns zero on success, or a negative errno value.
 485  */
 486 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 487 {
 488         struct nfs_delegation *delegation;
 489         struct nfs_delegation *prev;
 490         struct nfs_server *server;
 491         struct inode *inode;
 492         struct inode *place_holder = NULL;
 493         struct nfs_delegation *place_holder_deleg = NULL;
 494         int err = 0;
 495
 496 restart:
 497         /*
 498          * To avoid quadratic looping we hold a reference
 499          * to an inode place_holder.  Each time we restart, we
 500          * list nfs_servers from the server of that inode, and
 501          * delegation in the server from the delegations of that
 502          * inode.
 503          * prev is an RCU-protected pointer to a delegation which
 504          * wasn't marked for return and might be a good choice for
 505          * the next place_holder.
 506          */
 507         rcu_read_lock();
 508         prev = NULL;
 509         if (place_holder)
 510                 server = NFS_SERVER(place_holder);
 511         else
 512                 server = list_entry_rcu(clp->cl_superblocks.next,
 513                                         struct nfs_server, client_link);
 514         list_for_each_entry_from_rcu(server, &clp->cl_superblocks, client_link) {
 515                 delegation = NULL;
 516                 if (place_holder && server == NFS_SERVER(place_holder))
 517                         delegation = rcu_dereference(NFS_I(place_holder)->delegation);
 518                 if (!delegation || delegation != place_holder_deleg)
 519                         delegation = list_entry_rcu(server->delegations.next,
 520                                                     struct nfs_delegation, super_list);
 521                 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
 522                         struct inode *to_put = NULL;
 523
 524                         if (!nfs_delegation_need_return(delegation)) {
 525                                 prev = delegation;
 526                                 continue;
 527                         }
 528                         if (!nfs_sb_active(server->super))
 529                                 break; /* continue in outer loop */
 530
 531                         if (prev) {
 532                                 struct inode *tmp;
 533
 534                                 tmp = nfs_delegation_grab_inode(prev);
 535                                 if (tmp) {
 536                                         to_put = place_holder;
 537                                         place_holder = tmp;
 538                                         place_holder_deleg = prev;
 539                                 }
 540                         }
 541
 542                         inode = nfs_delegation_grab_inode(delegation);
 543                         if (inode == NULL) {
 544                                 rcu_read_unlock();
 545                                 if (to_put)
 546                                         iput(to_put);
 547                                 nfs_sb_deactive(server->super);
 548                                 goto restart;
 549                         }
 550                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 551                         rcu_read_unlock();
 552
 553                         if (to_put)
 554                                 iput(to_put);
 555
 556                         err = nfs_end_delegation_return(inode, delegation, 0);
 557                         iput(inode);
 558                         nfs_sb_deactive(server->super);
 559                         cond_resched();
 560                         if (!err)
 561                                 goto restart;
 562                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 563                         if (place_holder)
 564                                 iput(place_holder);
 565                         return err;
 566                 }
 567         }
 568         rcu_read_unlock();
 569         if (place_holder)
 570                 iput(place_holder);
 571         return 0;
 572 }
 573
 574 /**
 575  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 576  * @inode: inode to process
 577  *
 578  * Does not protect against delegation reclaims, therefore really only safe
 579  * to be called from nfs4_clear_inode().
 580  */
 581 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 582 {
 583         struct nfs_delegation *delegation;
 584
 585         delegation = nfs_inode_detach_delegation(inode);
 586         if (delegation != NULL)
 587                 nfs_do_return_delegation(inode, delegation, 1);
 588 }
 589
 590 /**
 591  * nfs_inode_return_delegation - synchronously return a delegation
 592  * @inode: inode to process
 593  *
 594  * This routine will always flush any dirty data to disk on the
 595  * assumption that if we need to return the delegation, then
 596  * we should stop caching.
 597  *
 598  * Returns zero on success, or a negative errno value.
 599  */
 600 int nfs4_inode_return_delegation(struct inode *inode)
 601 {
 602         struct nfs_inode *nfsi = NFS_I(inode);
 603         struct nfs_delegation *delegation;
 604         int err = 0;
 605
 606         nfs_wb_all(inode);
 607         delegation = nfs_start_delegation_return(nfsi);
 608         if (delegation != NULL)
 609                 err = nfs_end_delegation_return(inode, delegation, 1);
 610         return err;
 611 }
 612
 613 /**
 614  * nfs4_inode_make_writeable
 615  * @inode: pointer to inode
 616  *
 617  * Make the inode writeable by returning the delegation if necessary
 618  *
 619  * Returns zero on success, or a negative errno value.
 620  */
 621 int nfs4_inode_make_writeable(struct inode *inode)
 622 {
 623         if (!nfs4_has_session(NFS_SERVER(inode)->nfs_client) ||
 624             !nfs4_check_delegation(inode, FMODE_WRITE))
 625                 return nfs4_inode_return_delegation(inode);
 626         return 0;
 627 }
 628
 629 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 630                 struct nfs_delegation *delegation)
 631 {
 632         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 633         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 634 }
 635
 636 static void nfs_mark_return_delegation(struct nfs_server *server,
 637                 struct nfs_delegation *delegation)
 638 {
 639         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 640         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 641 }
 642
 643 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 644 {
 645         struct nfs_delegation *delegation;
 646         bool ret = false;
 647
 648         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 649                 nfs_mark_return_delegation(server, delegation);
 650                 ret = true;
 651         }
 652         return ret;
 653 }
 654
 655 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 656 {
 657         struct nfs_server *server;
 658
 659         rcu_read_lock();
 660         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 661                 nfs_server_mark_return_all_delegations(server);
 662         rcu_read_unlock();
 663 }
 664
 665 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 666 {
 667         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 668                 nfs4_schedule_state_manager(clp);
 669 }
 670
 671 /**
 672  * nfs_expire_all_delegations
 673  * @clp: client to process
 674  *
 675  */
 676 void nfs_expire_all_delegations(struct nfs_client *clp)
 677 {
 678         nfs_client_mark_return_all_delegations(clp);
 679         nfs_delegation_run_state_manager(clp);
 680 }
 681
 682 /**
 683  * nfs_super_return_all_delegations - return delegations for one superblock
 684  * @sb: sb to process
 685  *
 686  */
 687 void nfs_server_return_all_delegations(struct nfs_server *server)
 688 {
 689         struct nfs_client *clp = server->nfs_client;
 690         bool need_wait;
 691
 692         if (clp == NULL)
 693                 return;
 694
 695         rcu_read_lock();
 696         need_wait = nfs_server_mark_return_all_delegations(server);
 697         rcu_read_unlock();
 698
 699         if (need_wait) {
 700                 nfs4_schedule_state_manager(clp);
 701                 nfs4_wait_clnt_recover(clp);
 702         }
 703 }
 704
 705 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 706                                                  fmode_t flags)
 707 {
 708         struct nfs_delegation *delegation;
 709
 710         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 711                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 712                         continue;
 713                 if (delegation->type & flags)
 714                         nfs_mark_return_if_closed_delegation(server, delegation);
 715         }
 716 }
 717
 718 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 719                                                         fmode_t flags)
 720 {
 721         struct nfs_server *server;
 722
 723         rcu_read_lock();
 724         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 725                 nfs_mark_return_unused_delegation_types(server, flags);
 726         rcu_read_unlock();
 727 }
 728
 729 static void nfs_mark_delegation_revoked(struct nfs_server *server,
 730                 struct nfs_delegation *delegation)
 731 {
 732         set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 733         delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
 734         nfs_mark_return_delegation(server, delegation);
 735 }
 736
 737 static bool nfs_revoke_delegation(struct inode *inode,
 738                 const nfs4_stateid *stateid)
 739 {
 740         struct nfs_delegation *delegation;
 741         nfs4_stateid tmp;
 742         bool ret = false;
 743
 744         rcu_read_lock();
 745         delegation = rcu_dereference(NFS_I(inode)->delegation);
 746         if (delegation == NULL)
 747                 goto out;
 748         if (stateid == NULL) {
 749                 nfs4_stateid_copy(&tmp, &delegation->stateid);
 750                 stateid = &tmp;
 751         } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
 752                 goto out;
 753         nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
 754         ret = true;
 755 out:
 756         rcu_read_unlock();
 757         if (ret)
 758                 nfs_inode_find_state_and_recover(inode, stateid);
 759         return ret;
 760 }
 761
 762 void nfs_remove_bad_delegation(struct inode *inode,
 763                 const nfs4_stateid *stateid)
 764 {
 765         struct nfs_delegation *delegation;
 766
 767         if (!nfs_revoke_delegation(inode, stateid))
 768                 return;
 769         delegation = nfs_inode_detach_delegation(inode);
 770         if (delegation)
 771                 nfs_free_delegation(delegation);
 772 }
 773 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 774
 775 /**
 776  * nfs_expire_unused_delegation_types
 777  * @clp: client to process
 778  * @flags: delegation types to expire
 779  *
 780  */
 781 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 782 {
 783         nfs_client_mark_return_unused_delegation_types(clp, flags);
 784         nfs_delegation_run_state_manager(clp);
 785 }
 786
 787 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 788 {
 789         struct nfs_delegation *delegation;
 790
 791         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 792                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 793                         continue;
 794                 nfs_mark_return_if_closed_delegation(server, delegation);
 795         }
 796 }
 797
 798 /**
 799  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 800  * @clp: nfs_client to process
 801  *
 802  */
 803 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 804 {
 805         struct nfs_server *server;
 806
 807         rcu_read_lock();
 808         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 809                 nfs_mark_return_unreferenced_delegations(server);
 810         rcu_read_unlock();
 811
 812         nfs_delegation_run_state_manager(clp);
 813 }
 814
 815 /**
 816  * nfs_async_inode_return_delegation - asynchronously return a delegation
 817  * @inode: inode to process
 818  * @stateid: state ID information
 819  *
 820  * Returns zero on success, or a negative errno value.
 821  */
 822 int nfs_async_inode_return_delegation(struct inode *inode,
 823                                       const nfs4_stateid *stateid)
 824 {
 825         struct nfs_server *server = NFS_SERVER(inode);
 826         struct nfs_client *clp = server->nfs_client;
 827         struct nfs_delegation *delegation;
 828
 829         rcu_read_lock();
 830         delegation = rcu_dereference(NFS_I(inode)->delegation);
 831         if (delegation == NULL)
 832                 goto out_enoent;
 833         if (stateid != NULL &&
 834             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 835                 goto out_enoent;
 836         nfs_mark_return_delegation(server, delegation);
 837         rcu_read_unlock();
 838
 839         nfs_delegation_run_state_manager(clp);
 840         return 0;
 841 out_enoent:
 842         rcu_read_unlock();
 843         return -ENOENT;
 844 }
 845
 846 static struct inode *
 847 nfs_delegation_find_inode_server(struct nfs_server *server,
 848                                  const struct nfs_fh *fhandle)
 849 {
 850         struct nfs_delegation *delegation;
 851         struct inode *freeme, *res = NULL;
 852
 853         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 854                 spin_lock(&delegation->lock);
 855                 if (delegation->inode != NULL &&
 856                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 857                         freeme = igrab(delegation->inode);
 858                         if (freeme && nfs_sb_active(freeme->i_sb))
 859                                 res = freeme;
 860                         spin_unlock(&delegation->lock);
 861                         if (res != NULL)
 862                                 return res;
 863                         if (freeme) {
 864                                 rcu_read_unlock();
 865                                 iput(freeme);
 866                                 rcu_read_lock();
 867                         }
 868                         return ERR_PTR(-EAGAIN);
 869                 }
 870                 spin_unlock(&delegation->lock);
 871         }
 872         return ERR_PTR(-ENOENT);
 873 }
 874
 875 /**
 876  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 877  * @clp: client state handle
 878  * @fhandle: filehandle from a delegation recall
 879  *
 880  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 881  * cannot be found.
 882  */
 883 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 884                                         const struct nfs_fh *fhandle)
 885 {
 886         struct nfs_server *server;
 887         struct inode *res;
 888
 889         rcu_read_lock();
 890         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 891                 res = nfs_delegation_find_inode_server(server, fhandle);
 892                 if (res != ERR_PTR(-ENOENT)) {
 893                         rcu_read_unlock();
 894                         return res;
 895                 }
 896         }
 897         rcu_read_unlock();
 898         return ERR_PTR(-ENOENT);
 899 }
 900
 901 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 902 {
 903         struct nfs_delegation *delegation;
 904
 905         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 906                 /*
 907                  * If the delegation may have been admin revoked, then we
 908                  * cannot reclaim it.
 909                  */
 910                 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
 911                         continue;
 912                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 913         }
 914 }
 915
 916 /**
 917  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 918  * @clp: nfs_client to process
 919  *
 920  */
 921 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 922 {
 923         struct nfs_server *server;
 924
 925         rcu_read_lock();
 926         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 927                 nfs_delegation_mark_reclaim_server(server);
 928         rcu_read_unlock();
 929 }
 930
 931 /**
 932  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 933  * @clp: nfs_client to process
 934  *
 935  */
 936 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 937 {
 938         struct nfs_delegation *delegation;
 939         struct nfs_server *server;
 940         struct inode *inode;
 941
 942 restart:
 943         rcu_read_lock();
 944         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 945                 list_for_each_entry_rcu(delegation, &server->delegations,
 946                                                                 super_list) {
 947                         if (test_bit(NFS_DELEGATION_RETURNING,
 948                                                 &delegation->flags))
 949                                 continue;
 950                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 951                                                 &delegation->flags) == 0)
 952                                 continue;
 953                         if (!nfs_sb_active(server->super))
 954                                 break; /* continue in outer loop */
 955                         inode = nfs_delegation_grab_inode(delegation);
 956                         if (inode == NULL) {
 957                                 rcu_read_unlock();
 958                                 nfs_sb_deactive(server->super);
 959                                 goto restart;
 960                         }
 961                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 962                         rcu_read_unlock();
 963                         if (delegation != NULL) {
 964                                 delegation = nfs_detach_delegation(NFS_I(inode),
 965                                         delegation, server);
 966                                 if (delegation != NULL)
 967                                         nfs_free_delegation(delegation);
 968                         }
 969                         iput(inode);
 970                         nfs_sb_deactive(server->super);
 971                         cond_resched();
 972                         goto restart;
 973                 }
 974         }
 975         rcu_read_unlock();
 976 }
 977
 978 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
 979 {
 980         return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
 981                                 BIT(NFS4CLNT_LEASE_EXPIRED) |
 982                                 BIT(NFS4CLNT_SESSION_RESET))) != 0;
 983 }
 984
 985 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
 986             struct nfs_delegation *delegation)
 987 {
 988         if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
 989                 return;
 990         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 991         set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 992         set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
 993 }
 994
 995 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
 996                 struct inode *inode)
 997 {
 998         struct nfs_delegation *delegation;
 999
1000         rcu_read_lock();
1001         delegation = rcu_dereference(NFS_I(inode)->delegation);
1002         if (delegation)
1003                 nfs_mark_test_expired_delegation(server, delegation);
1004         rcu_read_unlock();
1005
1006 }
1007
1008 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1009 {
1010         struct nfs_delegation *delegation;
1011
1012         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1013                 nfs_mark_test_expired_delegation(server, delegation);
1014 }
1015
1016 /**
1017  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1018  * @clp: nfs_client to process
1019  *
1020  * Iterates through all the delegations associated with this server and
1021  * marks them as needing to be checked for validity.
1022  */
1023 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1024 {
1025         struct nfs_server *server;
1026
1027         rcu_read_lock();
1028         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1029                 nfs_delegation_mark_test_expired_server(server);
1030         rcu_read_unlock();
1031 }
1032
1033 /**
1034  * nfs_reap_expired_delegations - reap expired delegations
1035  * @clp: nfs_client to process
1036  *
1037  * Iterates through all the delegations associated with this server and
1038  * checks if they have may have been revoked. This function is usually
1039  * expected to be called in cases where the server may have lost its
1040  * lease.
1041  */
1042 void nfs_reap_expired_delegations(struct nfs_client *clp)
1043 {
1044         const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
1045         struct nfs_delegation *delegation;
1046         struct nfs_server *server;
1047         struct inode *inode;
1048         const struct cred *cred;
1049         nfs4_stateid stateid;
1050
1051 restart:
1052         rcu_read_lock();
1053         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1054                 list_for_each_entry_rcu(delegation, &server->delegations,
1055                                                                 super_list) {
1056                         if (test_bit(NFS_DELEGATION_RETURNING,
1057                                                 &delegation->flags))
1058                                 continue;
1059                         if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
1060                                                 &delegation->flags) == 0)
1061                                 continue;
1062                         if (!nfs_sb_active(server->super))
1063                                 break; /* continue in outer loop */
1064                         inode = nfs_delegation_grab_inode(delegation);
1065                         if (inode == NULL) {
1066                                 rcu_read_unlock();
1067                                 nfs_sb_deactive(server->super);
1068                                 goto restart;
1069                         }
1070                         cred = get_cred_rcu(delegation->cred);
1071                         nfs4_stateid_copy(&stateid, &delegation->stateid);
1072                         clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1073                         rcu_read_unlock();
1074                         if (cred != NULL &&
1075                             ops->test_and_free_expired(server, &stateid, cred) < 0) {
1076                                 nfs_revoke_delegation(inode, &stateid);
1077                                 nfs_inode_find_state_and_recover(inode, &stateid);
1078                         }
1079                         put_cred(cred);
1080                         if (nfs4_server_rebooted(clp)) {
1081                                 nfs_inode_mark_test_expired_delegation(server,inode);
1082                                 iput(inode);
1083                                 nfs_sb_deactive(server->super);
1084                                 return;
1085                         }
1086                         iput(inode);
1087                         nfs_sb_deactive(server->super);
1088                         cond_resched();
1089                         goto restart;
1090                 }
1091         }
1092         rcu_read_unlock();
1093 }
1094
1095 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1096                 const nfs4_stateid *stateid)
1097 {
1098         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1099         struct nfs_delegation *delegation;
1100         bool found = false;
1101
1102         rcu_read_lock();
1103         delegation = rcu_dereference(NFS_I(inode)->delegation);
1104         if (delegation &&
1105             nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1106                 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1107                 found = true;
1108         }
1109         rcu_read_unlock();
1110         if (found)
1111                 nfs4_schedule_state_manager(clp);
1112 }
1113
1114 /**
1115  * nfs_delegations_present - check for existence of delegations
1116  * @clp: client state handle
1117  *
1118  * Returns one if there are any nfs_delegation structures attached
1119  * to this nfs_client.
1120  */
1121 int nfs_delegations_present(struct nfs_client *clp)
1122 {
1123         struct nfs_server *server;
1124         int ret = 0;
1125
1126         rcu_read_lock();
1127         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1128                 if (!list_empty(&server->delegations)) {
1129                         ret = 1;
1130                         break;
1131                 }
1132         rcu_read_unlock();
1133         return ret;
1134 }
1135
1136 /**
1137  * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1138  * @dst: stateid to refresh
1139  * @inode: inode to check
1140  *
1141  * Returns "true" and updates "dst->seqid" * if inode had a delegation
1142  * that matches our delegation stateid. Otherwise "false" is returned.
1143  */
1144 bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1145 {
1146         struct nfs_delegation *delegation;
1147         bool ret = false;
1148         if (!inode)
1149                 goto out;
1150
1151         rcu_read_lock();
1152         delegation = rcu_dereference(NFS_I(inode)->delegation);
1153         if (delegation != NULL &&
1154             nfs4_stateid_match_other(dst, &delegation->stateid)) {
1155                 dst->seqid = delegation->stateid.seqid;
1156                 return ret;
1157         }
1158         rcu_read_unlock();
1159 out:
1160         return ret;
1161 }
1162
1163 /**
1164  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1165  * @inode: inode to check
1166  * @flags: delegation type requirement
1167  * @dst: stateid data structure to fill in
1168  * @cred: optional argument to retrieve credential
1169  *
1170  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1171  * otherwise "false" is returned.
1172  */
1173 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1174                 nfs4_stateid *dst, const struct cred **cred)
1175 {
1176         struct nfs_inode *nfsi = NFS_I(inode);
1177         struct nfs_delegation *delegation;
1178         bool ret;
1179
1180         flags &= FMODE_READ|FMODE_WRITE;
1181         rcu_read_lock();
1182         delegation = rcu_dereference(nfsi->delegation);
1183         ret = nfs4_is_valid_delegation(delegation, flags);
1184         if (ret) {
1185                 nfs4_stateid_copy(dst, &delegation->stateid);
1186                 nfs_mark_delegation_referenced(delegation);
1187                 if (cred)
1188                         *cred = get_cred(delegation->cred);
1189         }
1190         rcu_read_unlock();
1191         return ret;
1192 }
1193
1194 /**
1195  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1196  * @inode: inode to check
1197  *
1198  * This function checks the number of outstanding writes to the file
1199  * against the delegation 'space_limit' field to see if
1200  * the spec requires us to flush the file on close.
1201  */
1202 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1203 {
1204         struct nfs_inode *nfsi = NFS_I(inode);
1205         struct nfs_delegation *delegation;
1206         bool ret = true;
1207
1208         rcu_read_lock();
1209         delegation = rcu_dereference(nfsi->delegation);
1210         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1211                 goto out;
1212         if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1213                 ret = false;
1214 out:
1215         rcu_read_unlock();
1216         return ret;
1217 }