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 #define NFS_DEFAULT_DELEGATION_WATERMARK (5000U)
  29
  30 static atomic_long_t nfs_active_delegations;
  31 static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK;
  32
  33 static void __nfs_free_delegation(struct nfs_delegation *delegation)
  34 {
  35         put_cred(delegation->cred);
  36         delegation->cred = NULL;
  37         kfree_rcu(delegation, rcu);
  38 }
  39
  40 static void nfs_mark_delegation_revoked(struct nfs_delegation *delegation)
  41 {
  42         if (!test_and_set_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
  43                 delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
  44                 atomic_long_dec(&nfs_active_delegations);
  45                 if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
  46                         nfs_clear_verifier_delegated(delegation->inode);
  47         }
  48 }
  49
  50 static struct nfs_delegation *nfs_get_delegation(struct nfs_delegation *delegation)
  51 {
  52         refcount_inc(&delegation->refcount);
  53         return delegation;
  54 }
  55
  56 static void nfs_put_delegation(struct nfs_delegation *delegation)
  57 {
  58         if (refcount_dec_and_test(&delegation->refcount))
  59                 __nfs_free_delegation(delegation);
  60 }
  61
  62 static void nfs_free_delegation(struct nfs_delegation *delegation)
  63 {
  64         nfs_mark_delegation_revoked(delegation);
  65         nfs_put_delegation(delegation);
  66 }
  67
  68 /**
  69  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
  70  * @delegation: delegation to process
  71  *
  72  */
  73 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  74 {
  75         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  76 }
  77
  78 static void nfs_mark_return_delegation(struct nfs_server *server,
  79                                        struct nfs_delegation *delegation)
  80 {
  81         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
  82         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
  83 }
  84
  85 static bool nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
  86                                      fmode_t type)
  87 {
  88         if (delegation != NULL && (delegation->type & type) == type &&
  89             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
  90             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
  91                 return true;
  92         return false;
  93 }
  94
  95 struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode)
  96 {
  97         struct nfs_delegation *delegation;
  98
  99         delegation = rcu_dereference(NFS_I(inode)->delegation);
 100         if (nfs4_is_valid_delegation(delegation, 0))
 101                 return delegation;
 102         return NULL;
 103 }
 104
 105 static int nfs4_do_check_delegation(struct inode *inode, fmode_t type,
 106                                     int flags, bool mark)
 107 {
 108         struct nfs_delegation *delegation;
 109         int ret = 0;
 110
 111         type &= FMODE_READ|FMODE_WRITE;
 112         rcu_read_lock();
 113         delegation = rcu_dereference(NFS_I(inode)->delegation);
 114         if (nfs4_is_valid_delegation(delegation, type)) {
 115                 if (mark)
 116                         nfs_mark_delegation_referenced(delegation);
 117                 ret = 1;
 118                 if ((flags & NFS_DELEGATION_FLAG_TIME) &&
 119                     !test_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags))
 120                         ret = 0;
 121         }
 122         rcu_read_unlock();
 123         return ret;
 124 }
 125 /**
 126  * nfs4_have_delegation - check if inode has a delegation, mark it
 127  * NFS_DELEGATION_REFERENCED if there is one.
 128  * @inode: inode to check
 129  * @type: delegation types to check for
 130  * @flags: various modifiers
 131  *
 132  * Returns one if inode has the indicated delegation, otherwise zero.
 133  */
 134 int nfs4_have_delegation(struct inode *inode, fmode_t type, int flags)
 135 {
 136         return nfs4_do_check_delegation(inode, type, flags, true);
 137 }
 138
 139 /*
 140  * nfs4_check_delegation - check if inode has a delegation, do not mark
 141  * NFS_DELEGATION_REFERENCED if it has one.
 142  */
 143 int nfs4_check_delegation(struct inode *inode, fmode_t type)
 144 {
 145         return nfs4_do_check_delegation(inode, type, 0, false);
 146 }
 147
 148 static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
 149 {
 150         struct inode *inode = state->inode;
 151         struct file_lock *fl;
 152         struct file_lock_context *flctx = locks_inode_context(inode);
 153         struct list_head *list;
 154         int status = 0;
 155
 156         if (flctx == NULL)
 157                 goto out;
 158
 159         list = &flctx->flc_posix;
 160         spin_lock(&flctx->flc_lock);
 161 restart:
 162         for_each_file_lock(fl, list) {
 163                 if (nfs_file_open_context(fl->c.flc_file)->state != state)
 164                         continue;
 165                 spin_unlock(&flctx->flc_lock);
 166                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 167                 if (status < 0)
 168                         goto out;
 169                 spin_lock(&flctx->flc_lock);
 170         }
 171         if (list == &flctx->flc_posix) {
 172                 list = &flctx->flc_flock;
 173                 goto restart;
 174         }
 175         spin_unlock(&flctx->flc_lock);
 176 out:
 177         return status;
 178 }
 179
 180 static int nfs_delegation_claim_opens(struct inode *inode,
 181                 const nfs4_stateid *stateid, fmode_t type)
 182 {
 183         struct nfs_inode *nfsi = NFS_I(inode);
 184         struct nfs_open_context *ctx;
 185         struct nfs4_state_owner *sp;
 186         struct nfs4_state *state;
 187         int err;
 188
 189 again:
 190         rcu_read_lock();
 191         list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
 192                 state = ctx->state;
 193                 if (state == NULL)
 194                         continue;
 195                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 196                         continue;
 197                 if (!nfs4_valid_open_stateid(state))
 198                         continue;
 199                 if (!nfs4_stateid_match(&state->stateid, stateid))
 200                         continue;
 201                 if (!get_nfs_open_context(ctx))
 202                         continue;
 203                 rcu_read_unlock();
 204                 sp = state->owner;
 205                 /* Block nfs4_proc_unlck */
 206                 mutex_lock(&sp->so_delegreturn_mutex);
 207                 err = nfs4_open_delegation_recall(ctx, state, stateid);
 208                 if (!err)
 209                         err = nfs_delegation_claim_locks(state, stateid);
 210                 mutex_unlock(&sp->so_delegreturn_mutex);
 211                 put_nfs_open_context(ctx);
 212                 if (err != 0)
 213                         return err;
 214                 goto again;
 215         }
 216         rcu_read_unlock();
 217         return 0;
 218 }
 219
 220 /**
 221  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 222  * @inode: inode to process
 223  * @cred: credential to use for request
 224  * @type: delegation type
 225  * @stateid: delegation stateid
 226  * @pagemod_limit: write delegation "space_limit"
 227  * @deleg_type: raw delegation type
 228  *
 229  */
 230 void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
 231                                   fmode_t type, const nfs4_stateid *stateid,
 232                                   unsigned long pagemod_limit, u32 deleg_type)
 233 {
 234         struct nfs_delegation *delegation;
 235         const struct cred *oldcred = NULL;
 236
 237         rcu_read_lock();
 238         delegation = rcu_dereference(NFS_I(inode)->delegation);
 239         if (delegation != NULL) {
 240                 spin_lock(&delegation->lock);
 241                 nfs4_stateid_copy(&delegation->stateid, stateid);
 242                 delegation->type = type;
 243                 delegation->pagemod_limit = pagemod_limit;
 244                 oldcred = delegation->cred;
 245                 delegation->cred = get_cred(cred);
 246                 switch (deleg_type) {
 247                 case NFS4_OPEN_DELEGATE_READ_ATTRS_DELEG:
 248                 case NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG:
 249                         set_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags);
 250                         break;
 251                 default:
 252                         clear_bit(NFS_DELEGATION_DELEGTIME, &delegation->flags);
 253                 }
 254                 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 255                 if (test_and_clear_bit(NFS_DELEGATION_REVOKED,
 256                                        &delegation->flags))
 257                         atomic_long_inc(&nfs_active_delegations);
 258                 spin_unlock(&delegation->lock);
 259                 rcu_read_unlock();
 260                 put_cred(oldcred);
 261                 trace_nfs4_reclaim_delegation(inode, type);
 262         } else {
 263                 rcu_read_unlock();
 264                 nfs_inode_set_delegation(inode, cred, type, stateid,
 265                                          pagemod_limit, deleg_type);
 266         }
 267 }
 268
 269 static int nfs_do_return_delegation(struct inode *inode,
 270                                     struct nfs_delegation *delegation,
 271                                     int issync)
 272 {
 273         const struct cred *cred;
 274         int res = 0;
 275
 276         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
 277                 spin_lock(&delegation->lock);
 278                 cred = get_cred(delegation->cred);
 279                 spin_unlock(&delegation->lock);
 280                 res = nfs4_proc_delegreturn(inode, cred, &delegation->stateid,
 281                                             delegation, issync);
 282                 put_cred(cred);
 283         }
 284         return res;
 285 }
 286
 287 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 288 {
 289         struct inode *inode = NULL;
 290
 291         spin_lock(&delegation->lock);
 292         if (delegation->inode != NULL)
 293                 inode = igrab(delegation->inode);
 294         if (!inode)
 295                 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
 296         spin_unlock(&delegation->lock);
 297         return inode;
 298 }
 299
 300 static struct nfs_delegation *
 301 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 302 {
 303         struct nfs_delegation *ret = NULL;
 304         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 305
 306         if (delegation == NULL)
 307                 goto out;
 308         spin_lock(&delegation->lock);
 309         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
 310                 clear_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
 311                 /* Refcount matched in nfs_end_delegation_return() */
 312                 ret = nfs_get_delegation(delegation);
 313         }
 314         spin_unlock(&delegation->lock);
 315         if (ret)
 316                 nfs_clear_verifier_delegated(&nfsi->vfs_inode);
 317 out:
 318         return ret;
 319 }
 320
 321 static struct nfs_delegation *
 322 nfs_start_delegation_return(struct nfs_inode *nfsi)
 323 {
 324         struct nfs_delegation *delegation;
 325
 326         rcu_read_lock();
 327         delegation = nfs_start_delegation_return_locked(nfsi);
 328         rcu_read_unlock();
 329         return delegation;
 330 }
 331
 332 static void nfs_abort_delegation_return(struct nfs_delegation *delegation,
 333                                         struct nfs_client *clp, int err)
 334 {
 335
 336         spin_lock(&delegation->lock);
 337         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 338         if (err == -EAGAIN) {
 339                 set_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
 340                 set_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state);
 341         }
 342         spin_unlock(&delegation->lock);
 343 }
 344
 345 static struct nfs_delegation *
 346 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 347                 struct nfs_delegation *delegation,
 348                 struct nfs_client *clp)
 349 {
 350         struct nfs_delegation *deleg_cur =
 351                 rcu_dereference_protected(nfsi->delegation,
 352                                 lockdep_is_held(&clp->cl_lock));
 353
 354         if (deleg_cur == NULL || delegation != deleg_cur)
 355                 return NULL;
 356
 357         spin_lock(&delegation->lock);
 358         if (!delegation->inode) {
 359                 spin_unlock(&delegation->lock);
 360                 return NULL;
 361         }
 362         list_del_rcu(&delegation->super_list);
 363         delegation->inode = NULL;
 364         rcu_assign_pointer(nfsi->delegation, NULL);
 365         spin_unlock(&delegation->lock);
 366         return delegation;
 367 }
 368
 369 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 370                 struct nfs_delegation *delegation,
 371                 struct nfs_server *server)
 372 {
 373         struct nfs_client *clp = server->nfs_client;
 374
 375         spin_lock(&clp->cl_lock);
 376         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 377         spin_unlock(&clp->cl_lock);
 378         return delegation;
 379 }
 380
 381 static struct nfs_delegation *
 382 nfs_inode_detach_delegation(struct inode *inode)
 383 {
 384         struct nfs_inode *nfsi = NFS_I(inode);
 385         struct nfs_server *server = NFS_SERVER(inode);
 386         struct nfs_delegation *delegation;
 387
 388         rcu_read_lock();
 389         delegation = rcu_dereference(nfsi->delegation);
 390         if (delegation != NULL)
 391                 delegation = nfs_detach_delegation(nfsi, delegation, server);
 392         rcu_read_unlock();
 393         return delegation;
 394 }
 395
 396 static void
 397 nfs_update_delegation_cred(struct nfs_delegation *delegation,
 398                 const struct cred *cred)
 399 {
 400         const struct cred *old;
 401
 402         if (cred_fscmp(delegation->cred, cred) != 0) {
 403                 old = xchg(&delegation->cred, get_cred(cred));
 404                 put_cred(old);
 405         }
 406 }
 407
 408 static void
 409 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 410                 const struct nfs_delegation *update)
 411 {
 412         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 413                 delegation->stateid.seqid = update->stateid.seqid;
 414                 smp_wmb();
 415                 delegation->type = update->type;
 416                 delegation->pagemod_limit = update->pagemod_limit;
 417                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
 418                         delegation->change_attr = update->change_attr;
 419                         nfs_update_delegation_cred(delegation, update->cred);
 420                         /* smp_mb__before_atomic() is implicit due to xchg() */
 421                         clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 422                         atomic_long_inc(&nfs_active_delegations);
 423                 }
 424         }
 425 }
 426
 427 /**
 428  * nfs_inode_set_delegation - set up a delegation on an inode
 429  * @inode: inode to which delegation applies
 430  * @cred: cred to use for subsequent delegation processing
 431  * @type: delegation type
 432  * @stateid: delegation stateid
 433  * @pagemod_limit: write delegation "space_limit"
 434  * @deleg_type: raw delegation type
 435  *
 436  * Returns zero on success, or a negative errno value.
 437  */
 438 int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
 439                              fmode_t type, const nfs4_stateid *stateid,
 440                              unsigned long pagemod_limit, u32 deleg_type)
 441 {
 442         struct nfs_server *server = NFS_SERVER(inode);
 443         struct nfs_client *clp = server->nfs_client;
 444         struct nfs_inode *nfsi = NFS_I(inode);
 445         struct nfs_delegation *delegation, *old_delegation;
 446         struct nfs_delegation *freeme = NULL;
 447         int status = 0;
 448
 449         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL_ACCOUNT);
 450         if (delegation == NULL)
 451                 return -ENOMEM;
 452         nfs4_stateid_copy(&delegation->stateid, stateid);
 453         refcount_set(&delegation->refcount, 1);
 454         delegation->type = type;
 455         delegation->pagemod_limit = pagemod_limit;
 456         delegation->change_attr = inode_peek_iversion_raw(inode);
 457         delegation->cred = get_cred(cred);
 458         delegation->inode = inode;
 459         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 460         switch (deleg_type) {
 461         case NFS4_OPEN_DELEGATE_READ_ATTRS_DELEG:
 462         case NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG:
 463                 delegation->flags |= BIT(NFS_DELEGATION_DELEGTIME);
 464         }
 465         delegation->test_gen = 0;
 466         spin_lock_init(&delegation->lock);
 467
 468         spin_lock(&clp->cl_lock);
 469         old_delegation = rcu_dereference_protected(nfsi->delegation,
 470                                         lockdep_is_held(&clp->cl_lock));
 471         if (old_delegation == NULL)
 472                 goto add_new;
 473         /* Is this an update of the existing delegation? */
 474         if (nfs4_stateid_match_other(&old_delegation->stateid,
 475                                 &delegation->stateid)) {
 476                 spin_lock(&old_delegation->lock);
 477                 nfs_update_inplace_delegation(old_delegation,
 478                                 delegation);
 479                 spin_unlock(&old_delegation->lock);
 480                 goto out;
 481         }
 482         if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) {
 483                 /*
 484                  * Deal with broken servers that hand out two
 485                  * delegations for the same file.
 486                  * Allow for upgrades to a WRITE delegation, but
 487                  * nothing else.
 488                  */
 489                 dfprintk(FILE, "%s: server %s handed out "
 490                                 "a duplicate delegation!\n",
 491                                 __func__, clp->cl_hostname);
 492                 if (delegation->type == old_delegation->type ||
 493                     !(delegation->type & FMODE_WRITE)) {
 494                         freeme = delegation;
 495                         delegation = NULL;
 496                         goto out;
 497                 }
 498                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 499                                         &old_delegation->flags))
 500                         goto out;
 501         }
 502         freeme = nfs_detach_delegation_locked(nfsi, old_delegation, clp);
 503         if (freeme == NULL)
 504                 goto out;
 505 add_new:
 506         /*
 507          * If we didn't revalidate the change attribute before setting
 508          * the delegation, then pre-emptively ask for a full attribute
 509          * cache revalidation.
 510          */
 511         spin_lock(&inode->i_lock);
 512         if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_CHANGE)
 513                 nfs_set_cache_invalid(inode,
 514                         NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
 515                         NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
 516                         NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_NLINK |
 517                         NFS_INO_INVALID_OTHER | NFS_INO_INVALID_DATA |
 518                         NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL |
 519                         NFS_INO_INVALID_XATTR);
 520         spin_unlock(&inode->i_lock);
 521
 522         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 523         rcu_assign_pointer(nfsi->delegation, delegation);
 524         delegation = NULL;
 525
 526         atomic_long_inc(&nfs_active_delegations);
 527
 528         trace_nfs4_set_delegation(inode, type);
 529
 530         /* If we hold writebacks and have delegated mtime then update */
 531         if (deleg_type == NFS4_OPEN_DELEGATE_WRITE_ATTRS_DELEG &&
 532             nfs_have_writebacks(inode))
 533                 nfs_update_delegated_mtime(inode);
 534 out:
 535         spin_unlock(&clp->cl_lock);
 536         if (delegation != NULL)
 537                 __nfs_free_delegation(delegation);
 538         if (freeme != NULL) {
 539                 nfs_do_return_delegation(inode, freeme, 0);
 540                 nfs_free_delegation(freeme);
 541         }
 542         return status;
 543 }
 544
 545 /*
 546  * Basic procedure for returning a delegation to the server
 547  */
 548 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 549 {
 550         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 551         unsigned int mode = O_WRONLY | O_RDWR;
 552         int err = 0;
 553
 554         if (delegation == NULL)
 555                 return 0;
 556
 557         if (!issync)
 558                 mode |= O_NONBLOCK;
 559         /* Recall of any remaining application leases */
 560         err = break_lease(inode, mode);
 561
 562         while (err == 0) {
 563                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 564                         break;
 565                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 566                                 delegation->type);
 567                 if (!issync || err != -EAGAIN)
 568                         break;
 569                 /*
 570                  * Guard against state recovery
 571                  */
 572                 err = nfs4_wait_clnt_recover(clp);
 573         }
 574
 575         if (err) {
 576                 nfs_abort_delegation_return(delegation, clp, err);
 577                 goto out;
 578         }
 579
 580         err = nfs_do_return_delegation(inode, delegation, issync);
 581 out:
 582         /* Refcount matched in nfs_start_delegation_return_locked() */
 583         nfs_put_delegation(delegation);
 584         return err;
 585 }
 586
 587 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 588 {
 589         bool ret = false;
 590
 591         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 592                 ret = true;
 593         else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) {
 594                 struct inode *inode;
 595
 596                 spin_lock(&delegation->lock);
 597                 inode = delegation->inode;
 598                 if (inode && list_empty(&NFS_I(inode)->open_files))
 599                         ret = true;
 600                 spin_unlock(&delegation->lock);
 601         }
 602         if (ret)
 603                 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 604         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
 605             test_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags) ||
 606             test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 607                 ret = false;
 608
 609         return ret;
 610 }
 611
 612 static int nfs_server_return_marked_delegations(struct nfs_server *server,
 613                 void __always_unused *data)
 614 {
 615         struct nfs_delegation *delegation;
 616         struct nfs_delegation *prev;
 617         struct inode *inode;
 618         struct inode *place_holder = NULL;
 619         struct nfs_delegation *place_holder_deleg = NULL;
 620         int err = 0;
 621
 622 restart:
 623         /*
 624          * To avoid quadratic looping we hold a reference
 625          * to an inode place_holder.  Each time we restart, we
 626          * list delegation in the server from the delegations
 627          * of that inode.
 628          * prev is an RCU-protected pointer to a delegation which
 629          * wasn't marked for return and might be a good choice for
 630          * the next place_holder.
 631          */
 632         prev = NULL;
 633         delegation = NULL;
 634         rcu_read_lock();
 635         if (place_holder)
 636                 delegation = rcu_dereference(NFS_I(place_holder)->delegation);
 637         if (!delegation || delegation != place_holder_deleg)
 638                 delegation = list_entry_rcu(server->delegations.next,
 639                                             struct nfs_delegation, super_list);
 640         list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
 641                 struct inode *to_put = NULL;
 642
 643                 if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags))
 644                         continue;
 645                 if (!nfs_delegation_need_return(delegation)) {
 646                         if (nfs4_is_valid_delegation(delegation, 0))
 647                                 prev = delegation;
 648                         continue;
 649                 }
 650                 inode = nfs_delegation_grab_inode(delegation);
 651                 if (inode == NULL)
 652                         continue;
 653
 654                 if (prev) {
 655                         struct inode *tmp = nfs_delegation_grab_inode(prev);
 656                         if (tmp) {
 657                                 to_put = place_holder;
 658                                 place_holder = tmp;
 659                                 place_holder_deleg = prev;
 660                         }
 661                 }
 662
 663                 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 664                 rcu_read_unlock();
 665
 666                 iput(to_put);
 667
 668                 err = nfs_end_delegation_return(inode, delegation, 0);
 669                 iput(inode);
 670                 cond_resched();
 671                 if (!err)
 672                         goto restart;
 673                 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 674                 goto out;
 675         }
 676         rcu_read_unlock();
 677 out:
 678         iput(place_holder);
 679         return err;
 680 }
 681
 682 static bool nfs_server_clear_delayed_delegations(struct nfs_server *server)
 683 {
 684         struct nfs_delegation *d;
 685         bool ret = false;
 686
 687         list_for_each_entry_rcu (d, &server->delegations, super_list) {
 688                 if (!test_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags))
 689                         continue;
 690                 nfs_mark_return_delegation(server, d);
 691                 clear_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags);
 692                 ret = true;
 693         }
 694         return ret;
 695 }
 696
 697 static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp)
 698 {
 699         struct nfs_server *server;
 700         bool ret = false;
 701
 702         if (!test_and_clear_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state))
 703                 goto out;
 704         rcu_read_lock();
 705         list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) {
 706                 if (nfs_server_clear_delayed_delegations(server))
 707                         ret = true;
 708         }
 709         rcu_read_unlock();
 710 out:
 711         return ret;
 712 }
 713
 714 /**
 715  * nfs_client_return_marked_delegations - return previously marked delegations
 716  * @clp: nfs_client to process
 717  *
 718  * Note that this function is designed to be called by the state
 719  * manager thread. For this reason, it cannot flush the dirty data,
 720  * since that could deadlock in case of a state recovery error.
 721  *
 722  * Returns zero on success, or a negative errno value.
 723  */
 724 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 725 {
 726         int err = nfs_client_for_each_server(
 727                 clp, nfs_server_return_marked_delegations, NULL);
 728         if (err)
 729                 return err;
 730         /* If a return was delayed, sleep to prevent hard looping */
 731         if (nfs_client_clear_delayed_delegations(clp))
 732                 ssleep(1);
 733         return 0;
 734 }
 735
 736 /**
 737  * nfs_inode_evict_delegation - return delegation, don't reclaim opens
 738  * @inode: inode to process
 739  *
 740  * Does not protect against delegation reclaims, therefore really only safe
 741  * to be called from nfs4_clear_inode(). Guaranteed to always free
 742  * the delegation structure.
 743  */
 744 void nfs_inode_evict_delegation(struct inode *inode)
 745 {
 746         struct nfs_delegation *delegation;
 747
 748         delegation = nfs_inode_detach_delegation(inode);
 749         if (delegation != NULL) {
 750                 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 751                 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
 752                 nfs_do_return_delegation(inode, delegation, 1);
 753                 nfs_free_delegation(delegation);
 754         }
 755 }
 756
 757 /**
 758  * nfs4_inode_return_delegation - synchronously return a delegation
 759  * @inode: inode to process
 760  *
 761  * This routine will always flush any dirty data to disk on the
 762  * assumption that if we need to return the delegation, then
 763  * we should stop caching.
 764  *
 765  * Returns zero on success, or a negative errno value.
 766  */
 767 int nfs4_inode_return_delegation(struct inode *inode)
 768 {
 769         struct nfs_inode *nfsi = NFS_I(inode);
 770         struct nfs_delegation *delegation;
 771
 772         delegation = nfs_start_delegation_return(nfsi);
 773         if (delegation != NULL) {
 774                 /* Synchronous recall of any application leases */
 775                 break_lease(inode, O_WRONLY | O_RDWR);
 776                 if (S_ISREG(inode->i_mode))
 777                         nfs_wb_all(inode);
 778                 return nfs_end_delegation_return(inode, delegation, 1);
 779         }
 780         return 0;
 781 }
 782
 783 /**
 784  * nfs4_inode_return_delegation_on_close - asynchronously return a delegation
 785  * @inode: inode to process
 786  *
 787  * This routine is called on file close in order to determine if the
 788  * inode delegation needs to be returned immediately.
 789  */
 790 void nfs4_inode_return_delegation_on_close(struct inode *inode)
 791 {
 792         struct nfs_delegation *delegation;
 793         struct nfs_delegation *ret = NULL;
 794
 795         if (!inode)
 796                 return;
 797         rcu_read_lock();
 798         delegation = nfs4_get_valid_delegation(inode);
 799         if (!delegation)
 800                 goto out;
 801         if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||
 802             atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) {
 803                 spin_lock(&delegation->lock);
 804                 if (delegation->inode &&
 805                     list_empty(&NFS_I(inode)->open_files) &&
 806                     !test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
 807                         clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 808                         /* Refcount matched in nfs_end_delegation_return() */
 809                         ret = nfs_get_delegation(delegation);
 810                 }
 811                 spin_unlock(&delegation->lock);
 812                 if (ret)
 813                         nfs_clear_verifier_delegated(inode);
 814         }
 815 out:
 816         rcu_read_unlock();
 817         nfs_end_delegation_return(inode, ret, 0);
 818 }
 819
 820 /**
 821  * nfs4_inode_make_writeable
 822  * @inode: pointer to inode
 823  *
 824  * Make the inode writeable by returning the delegation if necessary
 825  *
 826  * Returns zero on success, or a negative errno value.
 827  */
 828 int nfs4_inode_make_writeable(struct inode *inode)
 829 {
 830         struct nfs_delegation *delegation;
 831
 832         rcu_read_lock();
 833         delegation = nfs4_get_valid_delegation(inode);
 834         if (delegation == NULL ||
 835             (nfs4_has_session(NFS_SERVER(inode)->nfs_client) &&
 836              (delegation->type & FMODE_WRITE))) {
 837                 rcu_read_unlock();
 838                 return 0;
 839         }
 840         rcu_read_unlock();
 841         return nfs4_inode_return_delegation(inode);
 842 }
 843
 844 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 845                 struct nfs_delegation *delegation)
 846 {
 847         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 848         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 849 }
 850
 851 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 852 {
 853         struct nfs_delegation *delegation;
 854         bool ret = false;
 855
 856         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 857                 nfs_mark_return_delegation(server, delegation);
 858                 ret = true;
 859         }
 860         return ret;
 861 }
 862
 863 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 864 {
 865         struct nfs_server *server;
 866
 867         rcu_read_lock();
 868         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 869                 nfs_server_mark_return_all_delegations(server);
 870         rcu_read_unlock();
 871 }
 872
 873 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 874 {
 875         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 876                 nfs4_schedule_state_manager(clp);
 877 }
 878
 879 /**
 880  * nfs_expire_all_delegations
 881  * @clp: client to process
 882  *
 883  */
 884 void nfs_expire_all_delegations(struct nfs_client *clp)
 885 {
 886         nfs_client_mark_return_all_delegations(clp);
 887         nfs_delegation_run_state_manager(clp);
 888 }
 889
 890 /**
 891  * nfs_server_return_all_delegations - return delegations for one superblock
 892  * @server: pointer to nfs_server to process
 893  *
 894  */
 895 void nfs_server_return_all_delegations(struct nfs_server *server)
 896 {
 897         struct nfs_client *clp = server->nfs_client;
 898         bool need_wait;
 899
 900         if (clp == NULL)
 901                 return;
 902
 903         rcu_read_lock();
 904         need_wait = nfs_server_mark_return_all_delegations(server);
 905         rcu_read_unlock();
 906
 907         if (need_wait) {
 908                 nfs4_schedule_state_manager(clp);
 909                 nfs4_wait_clnt_recover(clp);
 910         }
 911 }
 912
 913 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 914                                                  fmode_t flags)
 915 {
 916         struct nfs_delegation *delegation;
 917
 918         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 919                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 920                         continue;
 921                 if (delegation->type & flags)
 922                         nfs_mark_return_if_closed_delegation(server, delegation);
 923         }
 924 }
 925
 926 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 927                                                         fmode_t flags)
 928 {
 929         struct nfs_server *server;
 930
 931         rcu_read_lock();
 932         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 933                 nfs_mark_return_unused_delegation_types(server, flags);
 934         rcu_read_unlock();
 935 }
 936
 937 static void nfs_revoke_delegation(struct inode *inode,
 938                 const nfs4_stateid *stateid)
 939 {
 940         struct nfs_delegation *delegation;
 941         nfs4_stateid tmp;
 942         bool ret = false;
 943
 944         rcu_read_lock();
 945         delegation = rcu_dereference(NFS_I(inode)->delegation);
 946         if (delegation == NULL)
 947                 goto out;
 948         if (stateid == NULL) {
 949                 nfs4_stateid_copy(&tmp, &delegation->stateid);
 950                 stateid = &tmp;
 951         } else {
 952                 if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
 953                         goto out;
 954                 spin_lock(&delegation->lock);
 955                 if (stateid->seqid) {
 956                         if (nfs4_stateid_is_newer(&delegation->stateid, stateid)) {
 957                                 spin_unlock(&delegation->lock);
 958                                 goto out;
 959                         }
 960                         delegation->stateid.seqid = stateid->seqid;
 961                 }
 962                 spin_unlock(&delegation->lock);
 963         }
 964         nfs_mark_delegation_revoked(delegation);
 965         ret = true;
 966 out:
 967         rcu_read_unlock();
 968         if (ret)
 969                 nfs_inode_find_state_and_recover(inode, stateid);
 970 }
 971
 972 void nfs_remove_bad_delegation(struct inode *inode,
 973                 const nfs4_stateid *stateid)
 974 {
 975         nfs_revoke_delegation(inode, stateid);
 976 }
 977 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 978
 979 void nfs_delegation_mark_returned(struct inode *inode,
 980                 const nfs4_stateid *stateid)
 981 {
 982         struct nfs_delegation *delegation;
 983
 984         if (!inode)
 985                 return;
 986
 987         rcu_read_lock();
 988         delegation = rcu_dereference(NFS_I(inode)->delegation);
 989         if (!delegation)
 990                 goto out_rcu_unlock;
 991
 992         spin_lock(&delegation->lock);
 993         if (!nfs4_stateid_match_other(stateid, &delegation->stateid))
 994                 goto out_spin_unlock;
 995         if (stateid->seqid) {
 996                 /* If delegation->stateid is newer, dont mark as returned */
 997                 if (nfs4_stateid_is_newer(&delegation->stateid, stateid))
 998                         goto out_clear_returning;
 999                 if (delegation->stateid.seqid != stateid->seqid)
1000                         delegation->stateid.seqid = stateid->seqid;
1001         }
1002
1003         nfs_mark_delegation_revoked(delegation);
1004         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
1005         spin_unlock(&delegation->lock);
1006         if (nfs_detach_delegation(NFS_I(inode), delegation, NFS_SERVER(inode)))
1007                 nfs_put_delegation(delegation);
1008         goto out_rcu_unlock;
1009
1010 out_clear_returning:
1011         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
1012 out_spin_unlock:
1013         spin_unlock(&delegation->lock);
1014 out_rcu_unlock:
1015         rcu_read_unlock();
1016
1017         nfs_inode_find_state_and_recover(inode, stateid);
1018 }
1019
1020 /**
1021  * nfs_expire_unused_delegation_types
1022  * @clp: client to process
1023  * @flags: delegation types to expire
1024  *
1025  */
1026 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
1027 {
1028         nfs_client_mark_return_unused_delegation_types(clp, flags);
1029         nfs_delegation_run_state_manager(clp);
1030 }
1031
1032 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
1033 {
1034         struct nfs_delegation *delegation;
1035
1036         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1037                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
1038                         continue;
1039                 nfs_mark_return_if_closed_delegation(server, delegation);
1040         }
1041 }
1042
1043 /**
1044  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
1045  * @clp: nfs_client to process
1046  *
1047  */
1048 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
1049 {
1050         struct nfs_server *server;
1051
1052         rcu_read_lock();
1053         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1054                 nfs_mark_return_unreferenced_delegations(server);
1055         rcu_read_unlock();
1056
1057         nfs_delegation_run_state_manager(clp);
1058 }
1059
1060 /**
1061  * nfs_async_inode_return_delegation - asynchronously return a delegation
1062  * @inode: inode to process
1063  * @stateid: state ID information
1064  *
1065  * Returns zero on success, or a negative errno value.
1066  */
1067 int nfs_async_inode_return_delegation(struct inode *inode,
1068                                       const nfs4_stateid *stateid)
1069 {
1070         struct nfs_server *server = NFS_SERVER(inode);
1071         struct nfs_client *clp = server->nfs_client;
1072         struct nfs_delegation *delegation;
1073
1074         rcu_read_lock();
1075         delegation = nfs4_get_valid_delegation(inode);
1076         if (delegation == NULL)
1077                 goto out_enoent;
1078         if (stateid != NULL &&
1079             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
1080                 goto out_enoent;
1081         nfs_mark_return_delegation(server, delegation);
1082         rcu_read_unlock();
1083
1084         /* If there are any application leases or delegations, recall them */
1085         break_lease(inode, O_WRONLY | O_RDWR | O_NONBLOCK);
1086
1087         nfs_delegation_run_state_manager(clp);
1088         return 0;
1089 out_enoent:
1090         rcu_read_unlock();
1091         return -ENOENT;
1092 }
1093
1094 static struct inode *
1095 nfs_delegation_find_inode_server(struct nfs_server *server,
1096                                  const struct nfs_fh *fhandle)
1097 {
1098         struct nfs_delegation *delegation;
1099         struct super_block *freeme = NULL;
1100         struct inode *res = NULL;
1101
1102         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1103                 spin_lock(&delegation->lock);
1104                 if (delegation->inode != NULL &&
1105                     !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
1106                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
1107                         if (nfs_sb_active(server->super)) {
1108                                 freeme = server->super;
1109                                 res = igrab(delegation->inode);
1110                         }
1111                         spin_unlock(&delegation->lock);
1112                         if (res != NULL)
1113                                 return res;
1114                         if (freeme) {
1115                                 rcu_read_unlock();
1116                                 nfs_sb_deactive(freeme);
1117                                 rcu_read_lock();
1118                         }
1119                         return ERR_PTR(-EAGAIN);
1120                 }
1121                 spin_unlock(&delegation->lock);
1122         }
1123         return ERR_PTR(-ENOENT);
1124 }
1125
1126 /**
1127  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
1128  * @clp: client state handle
1129  * @fhandle: filehandle from a delegation recall
1130  *
1131  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
1132  * cannot be found.
1133  */
1134 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
1135                                         const struct nfs_fh *fhandle)
1136 {
1137         struct nfs_server *server;
1138         struct inode *res;
1139
1140         rcu_read_lock();
1141         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1142                 res = nfs_delegation_find_inode_server(server, fhandle);
1143                 if (res != ERR_PTR(-ENOENT)) {
1144                         rcu_read_unlock();
1145                         return res;
1146                 }
1147         }
1148         rcu_read_unlock();
1149         return ERR_PTR(-ENOENT);
1150 }
1151
1152 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
1153 {
1154         struct nfs_delegation *delegation;
1155
1156         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1157                 /*
1158                  * If the delegation may have been admin revoked, then we
1159                  * cannot reclaim it.
1160                  */
1161                 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
1162                         continue;
1163                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1164         }
1165 }
1166
1167 /**
1168  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
1169  * @clp: nfs_client to process
1170  *
1171  */
1172 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
1173 {
1174         struct nfs_server *server;
1175
1176         rcu_read_lock();
1177         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1178                 nfs_delegation_mark_reclaim_server(server);
1179         rcu_read_unlock();
1180 }
1181
1182 static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server,
1183                 void __always_unused *data)
1184 {
1185         struct nfs_delegation *delegation;
1186         struct inode *inode;
1187 restart:
1188         rcu_read_lock();
1189         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1190                 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1191                                         &delegation->flags) ||
1192                     test_bit(NFS_DELEGATION_RETURNING,
1193                                         &delegation->flags) ||
1194                     test_bit(NFS_DELEGATION_NEED_RECLAIM,
1195                                         &delegation->flags) == 0)
1196                         continue;
1197                 inode = nfs_delegation_grab_inode(delegation);
1198                 if (inode == NULL)
1199                         continue;
1200                 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
1201                 rcu_read_unlock();
1202                 if (delegation != NULL) {
1203                         if (nfs_detach_delegation(NFS_I(inode), delegation,
1204                                                 server) != NULL)
1205                                 nfs_free_delegation(delegation);
1206                         /* Match nfs_start_delegation_return_locked */
1207                         nfs_put_delegation(delegation);
1208                 }
1209                 iput(inode);
1210                 cond_resched();
1211                 goto restart;
1212         }
1213         rcu_read_unlock();
1214         return 0;
1215 }
1216
1217 /**
1218  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
1219  * @clp: nfs_client to process
1220  *
1221  */
1222 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
1223 {
1224         nfs_client_for_each_server(clp, nfs_server_reap_unclaimed_delegations,
1225                         NULL);
1226 }
1227
1228 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
1229 {
1230         return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
1231                                 BIT(NFS4CLNT_LEASE_EXPIRED) |
1232                                 BIT(NFS4CLNT_SESSION_RESET))) != 0;
1233 }
1234
1235 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
1236             struct nfs_delegation *delegation)
1237 {
1238         if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
1239                 return;
1240         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
1241         set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1242         set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
1243 }
1244
1245 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1246                 struct inode *inode)
1247 {
1248         struct nfs_delegation *delegation;
1249
1250         rcu_read_lock();
1251         delegation = rcu_dereference(NFS_I(inode)->delegation);
1252         if (delegation)
1253                 nfs_mark_test_expired_delegation(server, delegation);
1254         rcu_read_unlock();
1255
1256 }
1257
1258 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1259 {
1260         struct nfs_delegation *delegation;
1261
1262         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1263                 nfs_mark_test_expired_delegation(server, delegation);
1264 }
1265
1266 /**
1267  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1268  * @clp: nfs_client to process
1269  *
1270  * Iterates through all the delegations associated with this server and
1271  * marks them as needing to be checked for validity.
1272  */
1273 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1274 {
1275         struct nfs_server *server;
1276
1277         rcu_read_lock();
1278         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1279                 nfs_delegation_mark_test_expired_server(server);
1280         rcu_read_unlock();
1281 }
1282
1283 /**
1284  * nfs_test_expired_all_delegations - test all delegations for a client
1285  * @clp: nfs_client to process
1286  *
1287  * Helper for handling "recallable state revoked" status from server.
1288  */
1289 void nfs_test_expired_all_delegations(struct nfs_client *clp)
1290 {
1291         nfs_mark_test_expired_all_delegations(clp);
1292         nfs4_schedule_state_manager(clp);
1293 }
1294
1295 static void
1296 nfs_delegation_test_free_expired(struct inode *inode,
1297                 nfs4_stateid *stateid,
1298                 const struct cred *cred)
1299 {
1300         struct nfs_server *server = NFS_SERVER(inode);
1301         const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1302         int status;
1303
1304         if (!cred)
1305                 return;
1306         status = ops->test_and_free_expired(server, stateid, cred);
1307         if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1308                 nfs_remove_bad_delegation(inode, stateid);
1309 }
1310
1311 static int nfs_server_reap_expired_delegations(struct nfs_server *server,
1312                 void __always_unused *data)
1313 {
1314         struct nfs_delegation *delegation;
1315         struct inode *inode;
1316         const struct cred *cred;
1317         nfs4_stateid stateid;
1318         unsigned long gen = ++server->delegation_gen;
1319
1320 restart:
1321         rcu_read_lock();
1322         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
1323                 if (test_bit(NFS_DELEGATION_INODE_FREEING,
1324                                         &delegation->flags) ||
1325                     test_bit(NFS_DELEGATION_RETURNING,
1326                                         &delegation->flags) ||
1327                     test_bit(NFS_DELEGATION_TEST_EXPIRED,
1328                                         &delegation->flags) == 0 ||
1329                         delegation->test_gen == gen)
1330                         continue;
1331                 inode = nfs_delegation_grab_inode(delegation);
1332                 if (inode == NULL)
1333                         continue;
1334                 spin_lock(&delegation->lock);
1335                 cred = get_cred_rcu(delegation->cred);
1336                 nfs4_stateid_copy(&stateid, &delegation->stateid);
1337                 spin_unlock(&delegation->lock);
1338                 delegation->test_gen = gen;
1339                 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1340                 rcu_read_unlock();
1341                 nfs_delegation_test_free_expired(inode, &stateid, cred);
1342                 put_cred(cred);
1343                 if (!nfs4_server_rebooted(server->nfs_client)) {
1344                         iput(inode);
1345                         cond_resched();
1346                         goto restart;
1347                 }
1348                 nfs_inode_mark_test_expired_delegation(server,inode);
1349                 iput(inode);
1350                 return -EAGAIN;
1351         }
1352         rcu_read_unlock();
1353         return 0;
1354 }
1355
1356 /**
1357  * nfs_reap_expired_delegations - reap expired delegations
1358  * @clp: nfs_client to process
1359  *
1360  * Iterates through all the delegations associated with this server and
1361  * checks if they have may have been revoked. This function is usually
1362  * expected to be called in cases where the server may have lost its
1363  * lease.
1364  */
1365 void nfs_reap_expired_delegations(struct nfs_client *clp)
1366 {
1367         nfs_client_for_each_server(clp, nfs_server_reap_expired_delegations,
1368                         NULL);
1369 }
1370
1371 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1372                 const nfs4_stateid *stateid)
1373 {
1374         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1375         struct nfs_delegation *delegation;
1376         bool found = false;
1377
1378         rcu_read_lock();
1379         delegation = rcu_dereference(NFS_I(inode)->delegation);
1380         if (delegation &&
1381             nfs4_stateid_match_or_older(&delegation->stateid, stateid) &&
1382             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1383                 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1384                 found = true;
1385         }
1386         rcu_read_unlock();
1387         if (found)
1388                 nfs4_schedule_state_manager(clp);
1389 }
1390
1391 /**
1392  * nfs_delegations_present - check for existence of delegations
1393  * @clp: client state handle
1394  *
1395  * Returns one if there are any nfs_delegation structures attached
1396  * to this nfs_client.
1397  */
1398 int nfs_delegations_present(struct nfs_client *clp)
1399 {
1400         struct nfs_server *server;
1401         int ret = 0;
1402
1403         rcu_read_lock();
1404         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1405                 if (!list_empty(&server->delegations)) {
1406                         ret = 1;
1407                         break;
1408                 }
1409         rcu_read_unlock();
1410         return ret;
1411 }
1412
1413 /**
1414  * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1415  * @dst: stateid to refresh
1416  * @inode: inode to check
1417  *
1418  * Returns "true" and updates "dst->seqid" * if inode had a delegation
1419  * that matches our delegation stateid. Otherwise "false" is returned.
1420  */
1421 bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1422 {
1423         struct nfs_delegation *delegation;
1424         bool ret = false;
1425         if (!inode)
1426                 goto out;
1427
1428         rcu_read_lock();
1429         delegation = rcu_dereference(NFS_I(inode)->delegation);
1430         if (delegation != NULL &&
1431             nfs4_stateid_match_other(dst, &delegation->stateid) &&
1432             nfs4_stateid_is_newer(&delegation->stateid, dst) &&
1433             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
1434                 dst->seqid = delegation->stateid.seqid;
1435                 ret = true;
1436         }
1437         rcu_read_unlock();
1438 out:
1439         return ret;
1440 }
1441
1442 /**
1443  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1444  * @inode: inode to check
1445  * @flags: delegation type requirement
1446  * @dst: stateid data structure to fill in
1447  * @cred: optional argument to retrieve credential
1448  *
1449  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1450  * otherwise "false" is returned.
1451  */
1452 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1453                 nfs4_stateid *dst, const struct cred **cred)
1454 {
1455         struct nfs_inode *nfsi = NFS_I(inode);
1456         struct nfs_delegation *delegation;
1457         bool ret = false;
1458
1459         flags &= FMODE_READ|FMODE_WRITE;
1460         rcu_read_lock();
1461         delegation = rcu_dereference(nfsi->delegation);
1462         if (!delegation)
1463                 goto out;
1464         spin_lock(&delegation->lock);
1465         ret = nfs4_is_valid_delegation(delegation, flags);
1466         if (ret) {
1467                 nfs4_stateid_copy(dst, &delegation->stateid);
1468                 nfs_mark_delegation_referenced(delegation);
1469                 if (cred)
1470                         *cred = get_cred(delegation->cred);
1471         }
1472         spin_unlock(&delegation->lock);
1473 out:
1474         rcu_read_unlock();
1475         return ret;
1476 }
1477
1478 /**
1479  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1480  * @inode: inode to check
1481  *
1482  * This function checks the number of outstanding writes to the file
1483  * against the delegation 'space_limit' field to see if
1484  * the spec requires us to flush the file on close.
1485  */
1486 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1487 {
1488         struct nfs_inode *nfsi = NFS_I(inode);
1489         struct nfs_delegation *delegation;
1490         bool ret = true;
1491
1492         rcu_read_lock();
1493         delegation = rcu_dereference(nfsi->delegation);
1494         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1495                 goto out;
1496         if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1497                 ret = false;
1498 out:
1499         rcu_read_unlock();
1500         return ret;
1501 }
1502
1503 module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);