fs/nfs/delegation.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/fs/nfs/delegation.c
   4  *
   5  * Copyright (C) 2004 Trond Myklebust
   6  *
   7  * NFS file delegation management
   8  *
   9  */
  10 #include <linux/completion.h>
  11 #include <linux/kthread.h>
  12 #include <linux/module.h>
  13 #include <linux/sched.h>
  14 #include <linux/slab.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/iversion.h>
  17
  18 #include <linux/nfs4.h>
  19 #include <linux/nfs_fs.h>
  20 #include <linux/nfs_xdr.h>
  21
  22 #include "nfs4_fs.h"
  23 #include "nfs4session.h"
  24 #include "delegation.h"
  25 #include "internal.h"
  26 #include "nfs4trace.h"
  27
  28 static void nfs_free_delegation(struct nfs_delegation *delegation)
  29 {
  30         put_cred(delegation->cred);
  31         delegation->cred = NULL;
  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 struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
  57 {
  58         struct nfs_delegation *delegation;
  59
  60         delegation = rcu_dereference(NFS_I(inode)->delegation);
  61         if (nfs4_is_valid_delegation(delegation, 0))
  62                 return delegation;
  63         return NULL;
  64 }
  65
  66 static int
  67 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  68 {
  69         struct nfs_delegation *delegation;
  70         int ret = 0;
  71
  72         flags &= FMODE_READ|FMODE_WRITE;
  73         rcu_read_lock();
  74         delegation = rcu_dereference(NFS_I(inode)->delegation);
  75         if (nfs4_is_valid_delegation(delegation, flags)) {
  76                 if (mark)
  77                         nfs_mark_delegation_referenced(delegation);
  78                 ret = 1;
  79         }
  80         rcu_read_unlock();
  81         return ret;
  82 }
  83 /**
  84  * nfs_have_delegation - check if inode has a delegation, mark it
  85  * NFS_DELEGATION_REFERENCED if there is one.
  86  * @inode: inode to check
  87  * @flags: delegation types to check for
  88  *
  89  * Returns one if inode has the indicated delegation, otherwise zero.
  90  */
  91 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  92 {
  93         return nfs4_do_check_delegation(inode, flags, true);
  94 }
  95
  96 /*
  97  * nfs4_check_delegation - check if inode has a delegation, do not mark
  98  * NFS_DELEGATION_REFERENCED if it has one.
  99  */
 100 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
 101 {
 102         return nfs4_do_check_delegation(inode, flags, false);
 103 }
 104
 105 static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
 106 {
 107         struct inode *inode = state->inode;
 108         struct file_lock *fl;
 109         struct file_lock_context *flctx = inode->i_flctx;
 110         struct list_head *list;
 111         int status = 0;
 112
 113         if (flctx == NULL)
 114                 goto out;
 115
 116         list = &flctx->flc_posix;
 117         spin_lock(&flctx->flc_lock);
 118 restart:
 119         list_for_each_entry(fl, list, fl_list) {
 120                 if (nfs_file_open_context(fl->fl_file)->state != state)
 121                         continue;
 122                 spin_unlock(&flctx->flc_lock);
 123                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 124                 if (status < 0)
 125                         goto out;
 126                 spin_lock(&flctx->flc_lock);
 127         }
 128         if (list == &flctx->flc_posix) {
 129                 list = &flctx->flc_flock;
 130                 goto restart;
 131         }
 132         spin_unlock(&flctx->flc_lock);
 133 out:
 134         return status;
 135 }
 136
 137 static int nfs_delegation_claim_opens(struct inode *inode,
 138                 const nfs4_stateid *stateid, fmode_t type)
 139 {
 140         struct nfs_inode *nfsi = NFS_I(inode);
 141         struct nfs_open_context *ctx;
 142         struct nfs4_state_owner *sp;
 143         struct nfs4_state *state;
 144         unsigned int seq;
 145         int err;
 146
 147 again:
 148         rcu_read_lock();
 149         list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
 150                 state = ctx->state;
 151                 if (state == NULL)
 152                         continue;
 153                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 154                         continue;
 155                 if (!nfs4_valid_open_stateid(state))
 156                         continue;
 157                 if (!nfs4_stateid_match(&state->stateid, stateid))
 158                         continue;
 159                 if (!get_nfs_open_context(ctx))
 160                         continue;
 161                 rcu_read_unlock();
 162                 sp = state->owner;
 163                 /* Block nfs4_proc_unlck */
 164                 mutex_lock(&sp->so_delegreturn_mutex);
 165                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 166                 err = nfs4_open_delegation_recall(ctx, state, stateid);
 167                 if (!err)
 168                         err = nfs_delegation_claim_locks(state, stateid);
 169                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 170                         err = -EAGAIN;
 171                 mutex_unlock(&sp->so_delegreturn_mutex);
 172                 put_nfs_open_context(ctx);
 173                 if (err != 0)
 174                         return err;
 175                 goto again;
 176         }
 177         rcu_read_unlock();
 178         return 0;
 179 }
 180
 181 /**
 182  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 183  * @inode: inode to process
 184  * @cred: credential to use for request
 185  * @type: delegation type
 186  * @stateid: delegation stateid
 187  * @pagemod_limit: write delegation "space_limit"
 188  *
 189  */
 190 void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
 191                                   fmode_t type,
 192                                   const nfs4_stateid *stateid,
 193                                   unsigned long pagemod_limit)
 194 {
 195         struct nfs_delegation *delegation;
 196         const struct cred *oldcred = NULL;
 197
 198         rcu_read_lock();
 199         delegation = rcu_dereference(NFS_I(inode)->delegation);
 200         if (delegation != NULL) {
 201                 spin_lock(&delegation->lock);
 202                 if (delegation->inode != NULL) {
 203                         nfs4_stateid_copy(&delegation->stateid, stateid);
 204                         delegation->type = type;
 205                         delegation->pagemod_limit = pagemod_limit;
 206                         oldcred = delegation->cred;
 207                         delegation->cred = get_cred(cred);
 208                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 209                                   &delegation->flags);
 210                         spin_unlock(&delegation->lock);
 211                         rcu_read_unlock();
 212                         put_cred(oldcred);
 213                         trace_nfs4_reclaim_delegation(inode, type);
 214                         return;
 215                 }
 216                 /* We appear to have raced with a delegation return. */
 217                 spin_unlock(&delegation->lock);
 218         }
 219         rcu_read_unlock();
 220         nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
 221 }
 222
 223 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 224 {
 225         int res = 0;
 226
 227         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 228                 res = nfs4_proc_delegreturn(inode,
 229                                 delegation->cred,
 230                                 &delegation->stateid,
 231                                 issync);
 232         nfs_free_delegation(delegation);
 233         return res;
 234 }
 235
 236 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 237 {
 238         struct inode *inode = NULL;
 239
 240         spin_lock(&delegation->lock);
 241         if (delegation->inode != NULL)
 242                 inode = igrab(delegation->inode);
 243         if (!inode)
 244                 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
 245         spin_unlock(&delegation->lock);
 246         return inode;
 247 }
 248
 249 static struct nfs_delegation *
 250 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 251 {
 252         struct nfs_delegation *ret = NULL;
 253         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 254
 255         if (delegation == NULL)
 256                 goto out;
 257         spin_lock(&delegation->lock);
 258         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 259                 ret = delegation;
 260         spin_unlock(&delegation->lock);
 261 out:
 262         return ret;
 263 }
 264
 265 static struct nfs_delegation *
 266 nfs_start_delegation_return(struct nfs_inode *nfsi)
 267 {
 268         struct nfs_delegation *delegation;
 269
 270         rcu_read_lock();
 271         delegation = nfs_start_delegation_return_locked(nfsi);
 272         rcu_read_unlock();
 273         return delegation;
 274 }
 275
 276 static void
 277 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 278                 struct nfs_client *clp)
 279 {
 280
 281         spin_lock(&delegation->lock);
 282         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 283         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 284         spin_unlock(&delegation->lock);
 285         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 286 }
 287
 288 static struct nfs_delegation *
 289 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 290                 struct nfs_delegation *delegation,
 291                 struct nfs_client *clp)
 292 {
 293         struct nfs_delegation *deleg_cur =
 294                 rcu_dereference_protected(nfsi->delegation,
 295                                 lockdep_is_held(&clp->cl_lock));
 296
 297         if (deleg_cur == NULL || delegation != deleg_cur)
 298                 return NULL;
 299
 300         spin_lock(&delegation->lock);
 301         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 302         list_del_rcu(&delegation->super_list);
 303         delegation->inode = NULL;
 304         rcu_assign_pointer(nfsi->delegation, NULL);
 305         spin_unlock(&delegation->lock);
 306         return delegation;
 307 }
 308
 309 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 310                 struct nfs_delegation *delegation,
 311                 struct nfs_server *server)
 312 {
 313         struct nfs_client *clp = server->nfs_client;
 314
 315         spin_lock(&clp->cl_lock);
 316         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 317         spin_unlock(&clp->cl_lock);
 318         return delegation;
 319 }
 320
 321 static struct nfs_delegation *
 322 nfs_inode_detach_delegation(struct inode *inode)
 323 {
 324         struct nfs_inode *nfsi = NFS_I(inode);
 325         struct nfs_server *server = NFS_SERVER(inode);
 326         struct nfs_delegation *delegation;
 327
 328         delegation = nfs_start_delegation_return(nfsi);
 329         if (delegation == NULL)
 330                 return NULL;
 331         return nfs_detach_delegation(nfsi, delegation, server);
 332 }
 333
 334 static void
 335 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 336                 const struct nfs_delegation *update)
 337 {
 338         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 339                 delegation->stateid.seqid = update->stateid.seqid;
 340                 smp_wmb();
 341                 delegation->type = update->type;
 342         }
 343 }
 344
 345 /**
 346  * nfs_inode_set_delegation - set up a delegation on an inode
 347  * @inode: inode to which delegation applies
 348  * @cred: cred to use for subsequent delegation processing
 349  * @type: delegation type
 350  * @stateid: delegation stateid
 351  * @pagemod_limit: write delegation "space_limit"
 352  *
 353  * Returns zero on success, or a negative errno value.
 354  */
 355 int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
 356                                   fmode_t type,
 357                                   const nfs4_stateid *stateid,
 358                                   unsigned long pagemod_limit)
 359 {
 360         struct nfs_server *server = NFS_SERVER(inode);
 361         struct nfs_client *clp = server->nfs_client;
 362         struct nfs_inode *nfsi = NFS_I(inode);
 363         struct nfs_delegation *delegation, *old_delegation;
 364         struct nfs_delegation *freeme = NULL;
 365         int status = 0;
 366
 367         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 368         if (delegation == NULL)
 369                 return -ENOMEM;
 370         nfs4_stateid_copy(&delegation->stateid, stateid);
 371         delegation->type = type;
 372         delegation->pagemod_limit = pagemod_limit;
 373         delegation->change_attr = inode_peek_iversion_raw(inode);
 374         delegation->cred = get_cred(cred);
 375         delegation->inode = inode;
 376         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 377         spin_lock_init(&delegation->lock);
 378
 379         spin_lock(&clp->cl_lock);
 380         old_delegation = rcu_dereference_protected(nfsi->delegation,
 381                                         lockdep_is_held(&clp->cl_lock));
 382         if (old_delegation != NULL) {
 383                 /* Is this an update of the existing delegation? */
 384                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 385                                         &delegation->stateid)) {
 386                         nfs_update_inplace_delegation(old_delegation,
 387                                         delegation);
 388                         goto out;
 389                 }
 390                 /*
 391                  * Deal with broken servers that hand out two
 392                  * delegations for the same file.
 393                  * Allow for upgrades to a WRITE delegation, but
 394                  * nothing else.
 395                  */
 396                 dfprintk(FILE, "%s: server %s handed out "
 397                                 "a duplicate delegation!\n",
 398                                 __func__, clp->cl_hostname);
 399                 if (delegation->type == old_delegation->type ||
 400                     !(delegation->type & FMODE_WRITE)) {
 401                         freeme = delegation;
 402                         delegation = NULL;
 403                         goto out;
 404                 }
 405                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 406                                         &old_delegation->flags))
 407                         goto out;
 408                 freeme = nfs_detach_delegation_locked(nfsi,
 409                                 old_delegation, clp);
 410                 if (freeme == NULL)
 411                         goto out;
 412         }
 413         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 414         rcu_assign_pointer(nfsi->delegation, delegation);
 415         delegation = NULL;
 416
 417         trace_nfs4_set_delegation(inode, type);
 418
 419         spin_lock(&inode->i_lock);
 420         if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME))
 421                 NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED;
 422         spin_unlock(&inode->i_lock);
 423 out:
 424         spin_unlock(&clp->cl_lock);
 425         if (delegation != NULL)
 426                 nfs_free_delegation(delegation);
 427         if (freeme != NULL)
 428                 nfs_do_return_delegation(inode, freeme, 0);
 429         return status;
 430 }
 431
 432 /*
 433  * Basic procedure for returning a delegation to the server
 434  */
 435 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 436 {
 437         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 438         struct nfs_inode *nfsi = NFS_I(inode);
 439         int err = 0;
 440
 441         if (delegation == NULL)
 442                 return 0;
 443         do {
 444                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 445                         break;
 446                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 447                                 delegation->type);
 448                 if (!issync || err != -EAGAIN)
 449                         break;
 450                 /*
 451                  * Guard against state recovery
 452                  */
 453                 err = nfs4_wait_clnt_recover(clp);
 454         } while (err == 0);
 455
 456         if (err) {
 457                 nfs_abort_delegation_return(delegation, clp);
 458                 goto out;
 459         }
 460         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 461                 goto out;
 462
 463         err = nfs_do_return_delegation(inode, delegation, issync);
 464 out:
 465         return err;
 466 }
 467
 468 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 469 {
 470         bool ret = false;
 471
 472         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 473                 goto out;
 474         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 475                 ret = true;
 476         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 477                 struct inode *inode;
 478
 479                 spin_lock(&delegation->lock);
 480                 inode = delegation->inode;
 481                 if (inode && list_empty(&NFS_I(inode)->open_files))
 482                         ret = true;
 483                 spin_unlock(&delegation->lock);
 484         }
 485 out:
 486         return ret;
 487 }
 488
 489 /**
 490  * nfs_client_return_marked_delegations - return previously marked delegations
 491  * @clp: nfs_client to process
 492  *
 493  * Note that this function is designed to be called by the state
 494  * manager thread. For this reason, it cannot flush the dirty data,
 495  * since that could deadlock in case of a state recovery error.
 496  *
 497  * Returns zero on success, or a negative errno value.
 498  */
 499 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 500 {
 501         struct nfs_delegation *delegation;
 502         struct nfs_delegation *prev;
 503         struct nfs_server *server;
 504         struct inode *inode;
 505         struct inode *place_holder = NULL;
 506         struct nfs_delegation *place_holder_deleg = NULL;
 507         int err = 0;
 508
 509 restart:
 510         /*
 511          * To avoid quadratic looping we hold a reference
 512          * to an inode place_holder.  Each time we restart, we
 513          * list nfs_servers from the server of that inode, and
 514          * delegation in the server from the delegations of that
 515          * inode.
 516          * prev is an RCU-protected pointer to a delegation which
 517          * wasn't marked for return and might be a good choice for
 518          * the next place_holder.
 519          */
 520         rcu_read_lock();
 521         prev = NULL;
 522         if (place_holder)
 523                 server = NFS_SERVER(place_holder);
 524         else
 525                 server = list_entry_rcu(clp->cl_superblocks.next,
 526                                         struct nfs_server, client_link);
 527         list_for_each_entry_from_rcu(server, &clp->cl_superblocks, client_link) {
 528                 delegation = NULL;
 529                 if (place_holder && server == NFS_SERVER(place_holder))
 530                         delegation = rcu_dereference(NFS_I(place_holder)->delegation);
 531                 if (!delegation || delegation != place_holder_deleg)
 532                         delegation = list_entry_rcu(server->delegations.next,
 533                                                     struct nfs_delegation, super_list);
 534                 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
 535                         struct inode *to_put = NULL;
 536
 537                         if (!nfs_delegation_need_return(delegation)) {
 538                                 prev = delegation;
 539                                 continue;
 540                         }
 541                         if (!nfs_sb_active(server->super))
 542                                 break; /* continue in outer loop */
 543
 544                         if (prev) {
 545                                 struct inode *tmp;
 546
 547                                 tmp = nfs_delegation_grab_inode(prev);
 548                                 if (tmp) {
 549                                         to_put = place_holder;
 550                                         place_holder = tmp;
 551                                         place_holder_deleg = prev;
 552                                 }
 553                         }
 554
 555                         inode = nfs_delegation_grab_inode(delegation);
 556                         if (inode == NULL) {
 557                                 rcu_read_unlock();
 558                                 if (to_put)
 559                                         iput(to_put);
 560                                 nfs_sb_deactive(server->super);
 561                                 goto restart;
 562                         }
 563                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 564                         rcu_read_unlock();
 565
 566                         if (to_put)
 567                                 iput(to_put);
 568
 569                         err = nfs_end_delegation_return(inode, delegation, 0);
 570                         iput(inode);
 571                         nfs_sb_deactive(server->super);
 572                         cond_resched();
 573                         if (!err)
 574                                 goto restart;
 575                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 576                         if (place_holder)
 577                                 iput(place_holder);
 578                         return err;
 579                 }
 580         }
 581         rcu_read_unlock();
 582         if (place_holder)
 583                 iput(place_holder);
 584         return 0;
 585 }
 586
 587 /**
 588  * nfs_inode_evict_delegation - return delegation, don't reclaim opens
 589  * @inode: inode to process
 590  *
 591  * Does not protect against delegation reclaims, therefore really only safe
 592  * to be called from nfs4_clear_inode(). Guaranteed to always free
 593  * the delegation structure.
 594  */
 595 void nfs_inode_evict_delegation(struct inode *inode)
 596 {
 597         struct nfs_delegation *delegation;
 598
 599         delegation = nfs_inode_detach_delegation(inode);
 600         if (delegation != NULL) {
 601                 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
 602                 nfs_do_return_delegation(inode, delegation, 1);
 603         }
 604 }
 605
 606 /**
 607  * nfs_inode_return_delegation - synchronously return a delegation
 608  * @inode: inode to process
 609  *
 610  * This routine will always flush any dirty data to disk on the
 611  * assumption that if we need to return the delegation, then
 612  * we should stop caching.
 613  *
 614  * Returns zero on success, or a negative errno value.
 615  */
 616 int nfs4_inode_return_delegation(struct inode *inode)
 617 {
 618         struct nfs_inode *nfsi = NFS_I(inode);
 619         struct nfs_delegation *delegation;
 620         int err = 0;
 621
 622         nfs_wb_all(inode);
 623         delegation = nfs_start_delegation_return(nfsi);
 624         if (delegation != NULL)
 625                 err = nfs_end_delegation_return(inode, delegation, 1);
 626         return err;
 627 }
 628
 629 /**
 630  * nfs4_inode_make_writeable
 631  * @inode: pointer to inode
 632  *
 633  * Make the inode writeable by returning the delegation if necessary
 634  *
 635  * Returns zero on success, or a negative errno value.
 636  */
 637 int nfs4_inode_make_writeable(struct inode *inode)
 638 {
 639         if (!nfs4_has_session(NFS_SERVER(inode)->nfs_client) ||
 640             !nfs4_check_delegation(inode, FMODE_WRITE))
 641                 return nfs4_inode_return_delegation(inode);
 642         return 0;
 643 }
 644
 645 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 646                 struct nfs_delegation *delegation)
 647 {
 648         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 649         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 650 }
 651
 652 static void nfs_mark_return_delegation(struct nfs_server *server,
 653                 struct nfs_delegation *delegation)
 654 {
 655         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 656         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 657 }
 658
 659 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 660 {
 661         struct nfs_delegation *delegation;
 662         bool ret = false;
 663
 664         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 665                 nfs_mark_return_delegation(server, delegation);
 666                 ret = true;
 667         }
 668         return ret;
 669 }
 670
 671 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 672 {
 673         struct nfs_server *server;
 674
 675         rcu_read_lock();
 676         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 677                 nfs_server_mark_return_all_delegations(server);
 678         rcu_read_unlock();
 679 }
 680
 681 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 682 {
 683         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 684                 nfs4_schedule_state_manager(clp);
 685 }
 686
 687 /**
 688  * nfs_expire_all_delegations
 689  * @clp: client to process
 690  *
 691  */
 692 void nfs_expire_all_delegations(struct nfs_client *clp)
 693 {
 694         nfs_client_mark_return_all_delegations(clp);
 695         nfs_delegation_run_state_manager(clp);
 696 }
 697
 698 /**
 699  * nfs_super_return_all_delegations - return delegations for one superblock
 700  * @server: pointer to nfs_server to process
 701  *
 702  */
 703 void nfs_server_return_all_delegations(struct nfs_server *server)
 704 {
 705         struct nfs_client *clp = server->nfs_client;
 706         bool need_wait;
 707
 708         if (clp == NULL)
 709                 return;
 710
 711         rcu_read_lock();
 712         need_wait = nfs_server_mark_return_all_delegations(server);
 713         rcu_read_unlock();
 714
 715         if (need_wait) {
 716                 nfs4_schedule_state_manager(clp);
 717                 nfs4_wait_clnt_recover(clp);
 718         }
 719 }
 720
 721 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 722                                                  fmode_t flags)
 723 {
 724         struct nfs_delegation *delegation;
 725
 726         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 727                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 728                         continue;
 729                 if (delegation->type & flags)
 730                         nfs_mark_return_if_closed_delegation(server, delegation);
 731         }
 732 }
 733
 734 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 735                                                         fmode_t flags)
 736 {
 737         struct nfs_server *server;
 738
 739         rcu_read_lock();
 740         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 741                 nfs_mark_return_unused_delegation_types(server, flags);
 742         rcu_read_unlock();
 743 }
 744
 745 static void nfs_mark_delegation_revoked(struct nfs_server *server,
 746                 struct nfs_delegation *delegation)
 747 {
 748         set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 749         delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
 750         nfs_mark_return_delegation(server, delegation);
 751 }
 752
 753 static bool nfs_revoke_delegation(struct inode *inode,
 754                 const nfs4_stateid *stateid)
 755 {
 756         struct nfs_delegation *delegation;
 757         nfs4_stateid tmp;
 758         bool ret = false;
 759
 760         rcu_read_lock();
 761         delegation = rcu_dereference(NFS_I(inode)->delegation);
 762         if (delegation == NULL)
 763                 goto out;
 764         if (stateid == NULL) {
 765                 nfs4_stateid_copy(&tmp, &delegation->stateid);
 766                 stateid = &tmp;
 767         } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
 768                 goto out;
 769         nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
 770         ret = true;
 771 out:
 772         rcu_read_unlock();
 773         if (ret)
 774                 nfs_inode_find_state_and_recover(inode, stateid);
 775         return ret;
 776 }
 777
 778 void nfs_remove_bad_delegation(struct inode *inode,
 779                 const nfs4_stateid *stateid)
 780 {
 781         struct nfs_delegation *delegation;
 782
 783         if (!nfs_revoke_delegation(inode, stateid))
 784                 return;
 785         delegation = nfs_inode_detach_delegation(inode);
 786         if (delegation)
 787                 nfs_free_delegation(delegation);
 788 }
 789 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 790
 791 /**
 792  * nfs_expire_unused_delegation_types
 793  * @clp: client to process
 794  * @flags: delegation types to expire
 795  *
 796  */
 797 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 798 {
 799         nfs_client_mark_return_unused_delegation_types(clp, flags);
 800         nfs_delegation_run_state_manager(clp);
 801 }
 802
 803 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 804 {
 805         struct nfs_delegation *delegation;
 806
 807         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 808                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 809                         continue;
 810                 nfs_mark_return_if_closed_delegation(server, delegation);
 811         }
 812 }
 813
 814 /**
 815  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 816  * @clp: nfs_client to process
 817  *
 818  */
 819 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 820 {
 821         struct nfs_server *server;
 822
 823         rcu_read_lock();
 824         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 825                 nfs_mark_return_unreferenced_delegations(server);
 826         rcu_read_unlock();
 827
 828         nfs_delegation_run_state_manager(clp);
 829 }
 830
 831 /**
 832  * nfs_async_inode_return_delegation - asynchronously return a delegation
 833  * @inode: inode to process
 834  * @stateid: state ID information
 835  *
 836  * Returns zero on success, or a negative errno value.
 837  */
 838 int nfs_async_inode_return_delegation(struct inode *inode,
 839                                       const nfs4_stateid *stateid)
 840 {
 841         struct nfs_server *server = NFS_SERVER(inode);
 842         struct nfs_client *clp = server->nfs_client;
 843         struct nfs_delegation *delegation;
 844
 845         rcu_read_lock();
 846         delegation = nfs4_get_valid_delegation(inode);
 847         if (delegation == NULL)
 848                 goto out_enoent;
 849         if (stateid != NULL &&
 850             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 851                 goto out_enoent;
 852         nfs_mark_return_delegation(server, delegation);
 853         rcu_read_unlock();
 854
 855         nfs_delegation_run_state_manager(clp);
 856         return 0;
 857 out_enoent:
 858         rcu_read_unlock();
 859         return -ENOENT;
 860 }
 861
 862 static struct inode *
 863 nfs_delegation_find_inode_server(struct nfs_server *server,
 864                                  const struct nfs_fh *fhandle)
 865 {
 866         struct nfs_delegation *delegation;
 867         struct inode *freeme, *res = NULL;
 868
 869         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 870                 spin_lock(&delegation->lock);
 871                 if (delegation->inode != NULL &&
 872                     !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
 873                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 874                         freeme = igrab(delegation->inode);
 875                         if (freeme && nfs_sb_active(freeme->i_sb))
 876                                 res = freeme;
 877                         spin_unlock(&delegation->lock);
 878                         if (res != NULL)
 879                                 return res;
 880                         if (freeme) {
 881                                 rcu_read_unlock();
 882                                 iput(freeme);
 883                                 rcu_read_lock();
 884                         }
 885                         return ERR_PTR(-EAGAIN);
 886                 }
 887                 spin_unlock(&delegation->lock);
 888         }
 889         return ERR_PTR(-ENOENT);
 890 }
 891
 892 /**
 893  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 894  * @clp: client state handle
 895  * @fhandle: filehandle from a delegation recall
 896  *
 897  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 898  * cannot be found.
 899  */
 900 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 901                                         const struct nfs_fh *fhandle)
 902 {
 903         struct nfs_server *server;
 904         struct inode *res;
 905
 906         rcu_read_lock();
 907         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 908                 res = nfs_delegation_find_inode_server(server, fhandle);
 909                 if (res != ERR_PTR(-ENOENT)) {
 910                         rcu_read_unlock();
 911                         return res;
 912                 }
 913         }
 914         rcu_read_unlock();
 915         return ERR_PTR(-ENOENT);
 916 }
 917
 918 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 919 {
 920         struct nfs_delegation *delegation;
 921
 922         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 923                 /*
 924                  * If the delegation may have been admin revoked, then we
 925                  * cannot reclaim it.
 926                  */
 927                 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
 928                         continue;
 929                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 930         }
 931 }
 932
 933 /**
 934  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 935  * @clp: nfs_client to process
 936  *
 937  */
 938 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 939 {
 940         struct nfs_server *server;
 941
 942         rcu_read_lock();
 943         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 944                 nfs_delegation_mark_reclaim_server(server);
 945         rcu_read_unlock();
 946 }
 947
 948 /**
 949  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 950  * @clp: nfs_client to process
 951  *
 952  */
 953 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 954 {
 955         struct nfs_delegation *delegation;
 956         struct nfs_server *server;
 957         struct inode *inode;
 958
 959 restart:
 960         rcu_read_lock();
 961         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 962                 list_for_each_entry_rcu(delegation, &server->delegations,
 963                                                                 super_list) {
 964                         if (test_bit(NFS_DELEGATION_INODE_FREEING,
 965                                                 &delegation->flags) ||
 966                             test_bit(NFS_DELEGATION_RETURNING,
 967                                                 &delegation->flags) ||
 968                             test_bit(NFS_DELEGATION_NEED_RECLAIM,
 969                                                 &delegation->flags) == 0)
 970                                 continue;
 971                         if (!nfs_sb_active(server->super))
 972                                 break; /* continue in outer loop */
 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                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 980                         rcu_read_unlock();
 981                         if (delegation != NULL) {
 982                                 delegation = nfs_detach_delegation(NFS_I(inode),
 983                                         delegation, server);
 984                                 if (delegation != NULL)
 985                                         nfs_free_delegation(delegation);
 986                         }
 987                         iput(inode);
 988                         nfs_sb_deactive(server->super);
 989                         cond_resched();
 990                         goto restart;
 991                 }
 992         }
 993         rcu_read_unlock();
 994 }
 995
 996 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
 997 {
 998         return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
 999                                 BIT(NFS4CLNT_LEASE_EXPIRED) |
1000                                 BIT(NFS4CLNT_SESSION_RESET))) != 0;
1001 }
1002
1003 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
1004             struct nfs_delegation *delegation)
1005 {
1006         if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
1007                 return;
1008         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1009         set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1010         set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
1011 }
1012
1013 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1014                 struct inode *inode)
1015 {
1016         struct nfs_delegation *delegation;
1017
1018         rcu_read_lock();
1019         delegation = rcu_dereference(NFS_I(inode)->delegation);
1020         if (delegation)
1021                 nfs_mark_test_expired_delegation(server, delegation);
1022         rcu_read_unlock();
1023
1024 }
1025
1026 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1027 {
1028         struct nfs_delegation *delegation;
1029
1030         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1031                 nfs_mark_test_expired_delegation(server, delegation);
1032 }
1033
1034 /**
1035  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1036  * @clp: nfs_client to process
1037  *
1038  * Iterates through all the delegations associated with this server and
1039  * marks them as needing to be checked for validity.
1040  */
1041 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1042 {
1043         struct nfs_server *server;
1044
1045         rcu_read_lock();
1046         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1047                 nfs_delegation_mark_test_expired_server(server);
1048         rcu_read_unlock();
1049 }
1050
1051 /**
1052  * nfs_test_expired_all_delegations - test all delegations for a client
1053  * @clp: nfs_client to process
1054  *
1055  * Helper for handling "recallable state revoked" status from server.
1056  */
1057 void nfs_test_expired_all_delegations(struct nfs_client *clp)
1058 {
1059         nfs_mark_test_expired_all_delegations(clp);
1060         nfs4_schedule_state_manager(clp);
1061 }
1062
1063 static void
1064 nfs_delegation_test_free_expired(struct inode *inode,
1065                 nfs4_stateid *stateid,
1066                 const struct cred *cred)
1067 {
1068         struct nfs_server *server = NFS_SERVER(inode);
1069         const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1070         int status;
1071
1072         if (!cred)
1073                 return;
1074         status = ops->test_and_free_expired(server, stateid, cred);
1075         if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1076                 nfs_remove_bad_delegation(inode, stateid);
1077 }
1078
1079 /**
1080  * nfs_reap_expired_delegations - reap expired delegations
1081  * @clp: nfs_client to process
1082  *
1083  * Iterates through all the delegations associated with this server and
1084  * checks if they have may have been revoked. This function is usually
1085  * expected to be called in cases where the server may have lost its
1086  * lease.
1087  */
1088 void nfs_reap_expired_delegations(struct nfs_client *clp)
1089 {
1090         struct nfs_delegation *delegation;
1091         struct nfs_server *server;
1092         struct inode *inode;
1093         const struct cred *cred;
1094         nfs4_stateid stateid;
1095
1096 restart:
1097         rcu_read_lock();
1098         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1099                 list_for_each_entry_rcu(delegation, &server->delegations,
1100                                                                 super_list) {
1101                         if (test_bit(NFS_DELEGATION_INODE_FREEING,
1102                                                 &delegation->flags) ||
1103                             test_bit(NFS_DELEGATION_RETURNING,
1104                                                 &delegation->flags) ||
1105                             test_bit(NFS_DELEGATION_TEST_EXPIRED,
1106                                                 &delegation->flags) == 0)
1107                                 continue;
1108                         if (!nfs_sb_active(server->super))
1109                                 break; /* continue in outer loop */
1110                         inode = nfs_delegation_grab_inode(delegation);
1111                         if (inode == NULL) {
1112                                 rcu_read_unlock();
1113                                 nfs_sb_deactive(server->super);
1114                                 goto restart;
1115                         }
1116                         cred = get_cred_rcu(delegation->cred);
1117                         nfs4_stateid_copy(&stateid, &delegation->stateid);
1118                         clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1119                         rcu_read_unlock();
1120                         nfs_delegation_test_free_expired(inode, &stateid, cred);
1121                         put_cred(cred);
1122                         if (nfs4_server_rebooted(clp)) {
1123                                 nfs_inode_mark_test_expired_delegation(server,inode);
1124                                 iput(inode);
1125                                 nfs_sb_deactive(server->super);
1126                                 return;
1127                         }
1128                         iput(inode);
1129                         nfs_sb_deactive(server->super);
1130                         cond_resched();
1131                         goto restart;
1132                 }
1133         }
1134         rcu_read_unlock();
1135 }
1136
1137 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1138                 const nfs4_stateid *stateid)
1139 {
1140         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1141         struct nfs_delegation *delegation;
1142         bool found = false;
1143
1144         rcu_read_lock();
1145         delegation = rcu_dereference(NFS_I(inode)->delegation);
1146         if (delegation &&
1147             nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1148                 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1149                 found = true;
1150         }
1151         rcu_read_unlock();
1152         if (found)
1153                 nfs4_schedule_state_manager(clp);
1154 }
1155
1156 /**
1157  * nfs_delegations_present - check for existence of delegations
1158  * @clp: client state handle
1159  *
1160  * Returns one if there are any nfs_delegation structures attached
1161  * to this nfs_client.
1162  */
1163 int nfs_delegations_present(struct nfs_client *clp)
1164 {
1165         struct nfs_server *server;
1166         int ret = 0;
1167
1168         rcu_read_lock();
1169         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1170                 if (!list_empty(&server->delegations)) {
1171                         ret = 1;
1172                         break;
1173                 }
1174         rcu_read_unlock();
1175         return ret;
1176 }
1177
1178 /**
1179  * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1180  * @dst: stateid to refresh
1181  * @inode: inode to check
1182  *
1183  * Returns "true" and updates "dst->seqid" * if inode had a delegation
1184  * that matches our delegation stateid. Otherwise "false" is returned.
1185  */
1186 bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1187 {
1188         struct nfs_delegation *delegation;
1189         bool ret = false;
1190         if (!inode)
1191                 goto out;
1192
1193         rcu_read_lock();
1194         delegation = rcu_dereference(NFS_I(inode)->delegation);
1195         if (delegation != NULL &&
1196             nfs4_stateid_match_other(dst, &delegation->stateid) &&
1197             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1198                 dst->seqid = delegation->stateid.seqid;
1199                 ret = true;
1200         }
1201         rcu_read_unlock();
1202 out:
1203         return ret;
1204 }
1205
1206 /**
1207  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1208  * @inode: inode to check
1209  * @flags: delegation type requirement
1210  * @dst: stateid data structure to fill in
1211  * @cred: optional argument to retrieve credential
1212  *
1213  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1214  * otherwise "false" is returned.
1215  */
1216 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1217                 nfs4_stateid *dst, const struct cred **cred)
1218 {
1219         struct nfs_inode *nfsi = NFS_I(inode);
1220         struct nfs_delegation *delegation;
1221         bool ret;
1222
1223         flags &= FMODE_READ|FMODE_WRITE;
1224         rcu_read_lock();
1225         delegation = rcu_dereference(nfsi->delegation);
1226         ret = nfs4_is_valid_delegation(delegation, flags);
1227         if (ret) {
1228                 nfs4_stateid_copy(dst, &delegation->stateid);
1229                 nfs_mark_delegation_referenced(delegation);
1230                 if (cred)
1231                         *cred = get_cred(delegation->cred);
1232         }
1233         rcu_read_unlock();
1234         return ret;
1235 }
1236
1237 /**
1238  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1239  * @inode: inode to check
1240  *
1241  * This function checks the number of outstanding writes to the file
1242  * against the delegation 'space_limit' field to see if
1243  * the spec requires us to flush the file on close.
1244  */
1245 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1246 {
1247         struct nfs_inode *nfsi = NFS_I(inode);
1248         struct nfs_delegation *delegation;
1249         bool ret = true;
1250
1251         rcu_read_lock();
1252         delegation = rcu_dereference(nfsi->delegation);
1253         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1254                 goto out;
1255         if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1256                 ret = false;
1257 out:
1258         rcu_read_unlock();
1259         return ret;
1260 }