fs/nfs/delegation.c

   1 /*
   2  * linux/fs/nfs/delegation.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFS file delegation management
   7  *
   8  */
   9 #include <linux/completion.h>
  10 #include <linux/kthread.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15
  16 #include <linux/nfs4.h>
  17 #include <linux/nfs_fs.h>
  18 #include <linux/nfs_xdr.h>
  19
  20 #include "nfs4_fs.h"
  21 #include "delegation.h"
  22 #include "internal.h"
  23 #include "nfs4trace.h"
  24
  25 static void nfs_free_delegation(struct nfs_delegation *delegation)
  26 {
  27         if (delegation->cred) {
  28                 put_rpccred(delegation->cred);
  29                 delegation->cred = NULL;
  30         }
  31         kfree_rcu(delegation, rcu);
  32 }
  33
  34 /**
  35  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
  36  * @delegation: delegation to process
  37  *
  38  */
  39 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  40 {
  41         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  42 }
  43
  44 static bool
  45 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
  46                 fmode_t flags)
  47 {
  48         if (delegation != NULL && (delegation->type & flags) == flags &&
  49             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
  50             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
  51                 return true;
  52         return false;
  53 }
  54
  55 static int
  56 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  57 {
  58         struct nfs_delegation *delegation;
  59         int ret = 0;
  60
  61         flags &= FMODE_READ|FMODE_WRITE;
  62         rcu_read_lock();
  63         delegation = rcu_dereference(NFS_I(inode)->delegation);
  64         if (nfs4_is_valid_delegation(delegation, flags)) {
  65                 if (mark)
  66                         nfs_mark_delegation_referenced(delegation);
  67                 ret = 1;
  68         }
  69         rcu_read_unlock();
  70         return ret;
  71 }
  72 /**
  73  * nfs_have_delegation - check if inode has a delegation, mark it
  74  * NFS_DELEGATION_REFERENCED if there is one.
  75  * @inode: inode to check
  76  * @flags: delegation types to check for
  77  *
  78  * Returns one if inode has the indicated delegation, otherwise zero.
  79  */
  80 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  81 {
  82         return nfs4_do_check_delegation(inode, flags, true);
  83 }
  84
  85 /*
  86  * nfs4_check_delegation - check if inode has a delegation, do not mark
  87  * NFS_DELEGATION_REFERENCED if it has one.
  88  */
  89 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
  90 {
  91         return nfs4_do_check_delegation(inode, flags, false);
  92 }
  93
  94 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
  95 {
  96         struct inode *inode = state->inode;
  97         struct file_lock *fl;
  98         struct file_lock_context *flctx = inode->i_flctx;
  99         struct list_head *list;
 100         int status = 0;
 101
 102         if (flctx == NULL)
 103                 goto out;
 104
 105         list = &flctx->flc_posix;
 106         spin_lock(&flctx->flc_lock);
 107 restart:
 108         list_for_each_entry(fl, list, fl_list) {
 109                 if (nfs_file_open_context(fl->fl_file) != ctx)
 110                         continue;
 111                 spin_unlock(&flctx->flc_lock);
 112                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 113                 if (status < 0)
 114                         goto out;
 115                 spin_lock(&flctx->flc_lock);
 116         }
 117         if (list == &flctx->flc_posix) {
 118                 list = &flctx->flc_flock;
 119                 goto restart;
 120         }
 121         spin_unlock(&flctx->flc_lock);
 122 out:
 123         return status;
 124 }
 125
 126 static int nfs_delegation_claim_opens(struct inode *inode,
 127                 const nfs4_stateid *stateid, fmode_t type)
 128 {
 129         struct nfs_inode *nfsi = NFS_I(inode);
 130         struct nfs_open_context *ctx;
 131         struct nfs4_state_owner *sp;
 132         struct nfs4_state *state;
 133         unsigned int seq;
 134         int err;
 135
 136 again:
 137         spin_lock(&inode->i_lock);
 138         list_for_each_entry(ctx, &nfsi->open_files, list) {
 139                 state = ctx->state;
 140                 if (state == NULL)
 141                         continue;
 142                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 143                         continue;
 144                 if (!nfs4_valid_open_stateid(state))
 145                         continue;
 146                 if (!nfs4_stateid_match(&state->stateid, stateid))
 147                         continue;
 148                 get_nfs_open_context(ctx);
 149                 spin_unlock(&inode->i_lock);
 150                 sp = state->owner;
 151                 /* Block nfs4_proc_unlck */
 152                 mutex_lock(&sp->so_delegreturn_mutex);
 153                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 154                 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
 155                 if (!err)
 156                         err = nfs_delegation_claim_locks(ctx, state, stateid);
 157                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 158                         err = -EAGAIN;
 159                 mutex_unlock(&sp->so_delegreturn_mutex);
 160                 put_nfs_open_context(ctx);
 161                 if (err != 0)
 162                         return err;
 163                 goto again;
 164         }
 165         spin_unlock(&inode->i_lock);
 166         return 0;
 167 }
 168
 169 /**
 170  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 171  * @inode: inode to process
 172  * @cred: credential to use for request
 173  * @res: new delegation state from server
 174  *
 175  */
 176 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
 177                                   struct nfs_openres *res)
 178 {
 179         struct nfs_delegation *delegation;
 180         struct rpc_cred *oldcred = NULL;
 181
 182         rcu_read_lock();
 183         delegation = rcu_dereference(NFS_I(inode)->delegation);
 184         if (delegation != NULL) {
 185                 spin_lock(&delegation->lock);
 186                 if (delegation->inode != NULL) {
 187                         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 188                         delegation->type = res->delegation_type;
 189                         delegation->pagemod_limit = res->pagemod_limit;
 190                         oldcred = delegation->cred;
 191                         delegation->cred = get_rpccred(cred);
 192                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 193                                   &delegation->flags);
 194                         spin_unlock(&delegation->lock);
 195                         rcu_read_unlock();
 196                         put_rpccred(oldcred);
 197                         trace_nfs4_reclaim_delegation(inode, res->delegation_type);
 198                         return;
 199                 }
 200                 /* We appear to have raced with a delegation return. */
 201                 spin_unlock(&delegation->lock);
 202         }
 203         rcu_read_unlock();
 204         nfs_inode_set_delegation(inode, cred, res);
 205 }
 206
 207 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 208 {
 209         int res = 0;
 210
 211         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 212                 res = nfs4_proc_delegreturn(inode,
 213                                 delegation->cred,
 214                                 &delegation->stateid,
 215                                 issync);
 216         nfs_free_delegation(delegation);
 217         return res;
 218 }
 219
 220 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 221 {
 222         struct inode *inode = NULL;
 223
 224         spin_lock(&delegation->lock);
 225         if (delegation->inode != NULL)
 226                 inode = igrab(delegation->inode);
 227         spin_unlock(&delegation->lock);
 228         return inode;
 229 }
 230
 231 static struct nfs_delegation *
 232 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 233 {
 234         struct nfs_delegation *ret = NULL;
 235         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 236
 237         if (delegation == NULL)
 238                 goto out;
 239         spin_lock(&delegation->lock);
 240         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 241                 ret = delegation;
 242         spin_unlock(&delegation->lock);
 243 out:
 244         return ret;
 245 }
 246
 247 static struct nfs_delegation *
 248 nfs_start_delegation_return(struct nfs_inode *nfsi)
 249 {
 250         struct nfs_delegation *delegation;
 251
 252         rcu_read_lock();
 253         delegation = nfs_start_delegation_return_locked(nfsi);
 254         rcu_read_unlock();
 255         return delegation;
 256 }
 257
 258 static void
 259 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 260                 struct nfs_client *clp)
 261 {
 262
 263         spin_lock(&delegation->lock);
 264         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 265         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 266         spin_unlock(&delegation->lock);
 267         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 268 }
 269
 270 static struct nfs_delegation *
 271 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 272                 struct nfs_delegation *delegation,
 273                 struct nfs_client *clp)
 274 {
 275         struct nfs_delegation *deleg_cur =
 276                 rcu_dereference_protected(nfsi->delegation,
 277                                 lockdep_is_held(&clp->cl_lock));
 278
 279         if (deleg_cur == NULL || delegation != deleg_cur)
 280                 return NULL;
 281
 282         spin_lock(&delegation->lock);
 283         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 284         list_del_rcu(&delegation->super_list);
 285         delegation->inode = NULL;
 286         rcu_assign_pointer(nfsi->delegation, NULL);
 287         spin_unlock(&delegation->lock);
 288         return delegation;
 289 }
 290
 291 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 292                 struct nfs_delegation *delegation,
 293                 struct nfs_server *server)
 294 {
 295         struct nfs_client *clp = server->nfs_client;
 296
 297         spin_lock(&clp->cl_lock);
 298         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 299         spin_unlock(&clp->cl_lock);
 300         return delegation;
 301 }
 302
 303 static struct nfs_delegation *
 304 nfs_inode_detach_delegation(struct inode *inode)
 305 {
 306         struct nfs_inode *nfsi = NFS_I(inode);
 307         struct nfs_server *server = NFS_SERVER(inode);
 308         struct nfs_delegation *delegation;
 309
 310         delegation = nfs_start_delegation_return(nfsi);
 311         if (delegation == NULL)
 312                 return NULL;
 313         return nfs_detach_delegation(nfsi, delegation, server);
 314 }
 315
 316 static void
 317 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 318                 const struct nfs_delegation *update)
 319 {
 320         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 321                 delegation->stateid.seqid = update->stateid.seqid;
 322                 smp_wmb();
 323                 delegation->type = update->type;
 324         }
 325 }
 326
 327 /**
 328  * nfs_inode_set_delegation - set up a delegation on an inode
 329  * @inode: inode to which delegation applies
 330  * @cred: cred to use for subsequent delegation processing
 331  * @res: new delegation state from server
 332  *
 333  * Returns zero on success, or a negative errno value.
 334  */
 335 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 336 {
 337         struct nfs_server *server = NFS_SERVER(inode);
 338         struct nfs_client *clp = server->nfs_client;
 339         struct nfs_inode *nfsi = NFS_I(inode);
 340         struct nfs_delegation *delegation, *old_delegation;
 341         struct nfs_delegation *freeme = NULL;
 342         int status = 0;
 343
 344         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 345         if (delegation == NULL)
 346                 return -ENOMEM;
 347         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 348         delegation->type = res->delegation_type;
 349         delegation->pagemod_limit = res->pagemod_limit;
 350         delegation->change_attr = inode->i_version;
 351         delegation->cred = get_rpccred(cred);
 352         delegation->inode = inode;
 353         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 354         spin_lock_init(&delegation->lock);
 355
 356         spin_lock(&clp->cl_lock);
 357         old_delegation = rcu_dereference_protected(nfsi->delegation,
 358                                         lockdep_is_held(&clp->cl_lock));
 359         if (old_delegation != NULL) {
 360                 /* Is this an update of the existing delegation? */
 361                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 362                                         &delegation->stateid)) {
 363                         nfs_update_inplace_delegation(old_delegation,
 364                                         delegation);
 365                         goto out;
 366                 }
 367                 /*
 368                  * Deal with broken servers that hand out two
 369                  * delegations for the same file.
 370                  * Allow for upgrades to a WRITE delegation, but
 371                  * nothing else.
 372                  */
 373                 dfprintk(FILE, "%s: server %s handed out "
 374                                 "a duplicate delegation!\n",
 375                                 __func__, clp->cl_hostname);
 376                 if (delegation->type == old_delegation->type ||
 377                     !(delegation->type & FMODE_WRITE)) {
 378                         freeme = delegation;
 379                         delegation = NULL;
 380                         goto out;
 381                 }
 382                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 383                                         &old_delegation->flags))
 384                         goto out;
 385                 freeme = nfs_detach_delegation_locked(nfsi,
 386                                 old_delegation, clp);
 387                 if (freeme == NULL)
 388                         goto out;
 389         }
 390         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 391         rcu_assign_pointer(nfsi->delegation, delegation);
 392         delegation = NULL;
 393
 394         trace_nfs4_set_delegation(inode, res->delegation_type);
 395
 396 out:
 397         spin_unlock(&clp->cl_lock);
 398         if (delegation != NULL)
 399                 nfs_free_delegation(delegation);
 400         if (freeme != NULL)
 401                 nfs_do_return_delegation(inode, freeme, 0);
 402         return status;
 403 }
 404
 405 /*
 406  * Basic procedure for returning a delegation to the server
 407  */
 408 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 409 {
 410         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 411         struct nfs_inode *nfsi = NFS_I(inode);
 412         int err = 0;
 413
 414         if (delegation == NULL)
 415                 return 0;
 416         do {
 417                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 418                         break;
 419                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 420                                 delegation->type);
 421                 if (!issync || err != -EAGAIN)
 422                         break;
 423                 /*
 424                  * Guard against state recovery
 425                  */
 426                 err = nfs4_wait_clnt_recover(clp);
 427         } while (err == 0);
 428
 429         if (err) {
 430                 nfs_abort_delegation_return(delegation, clp);
 431                 goto out;
 432         }
 433         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 434                 goto out;
 435
 436         err = nfs_do_return_delegation(inode, delegation, issync);
 437 out:
 438         return err;
 439 }
 440
 441 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 442 {
 443         bool ret = false;
 444
 445         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 446                 goto out;
 447         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 448                 ret = true;
 449         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 450                 struct inode *inode;
 451
 452                 spin_lock(&delegation->lock);
 453                 inode = delegation->inode;
 454                 if (inode && list_empty(&NFS_I(inode)->open_files))
 455                         ret = true;
 456                 spin_unlock(&delegation->lock);
 457         }
 458 out:
 459         return ret;
 460 }
 461
 462 /**
 463  * nfs_client_return_marked_delegations - return previously marked delegations
 464  * @clp: nfs_client to process
 465  *
 466  * Note that this function is designed to be called by the state
 467  * manager thread. For this reason, it cannot flush the dirty data,
 468  * since that could deadlock in case of a state recovery error.
 469  *
 470  * Returns zero on success, or a negative errno value.
 471  */
 472 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 473 {
 474         struct nfs_delegation *delegation;
 475         struct nfs_server *server;
 476         struct inode *inode;
 477         int err = 0;
 478
 479 restart:
 480         rcu_read_lock();
 481         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 482                 list_for_each_entry_rcu(delegation, &server->delegations,
 483                                                                 super_list) {
 484                         if (!nfs_delegation_need_return(delegation))
 485                                 continue;
 486                         if (!nfs_sb_active(server->super))
 487                                 continue;
 488                         inode = nfs_delegation_grab_inode(delegation);
 489                         if (inode == NULL) {
 490                                 rcu_read_unlock();
 491                                 nfs_sb_deactive(server->super);
 492                                 goto restart;
 493                         }
 494                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 495                         rcu_read_unlock();
 496
 497                         err = nfs_end_delegation_return(inode, delegation, 0);
 498                         iput(inode);
 499                         nfs_sb_deactive(server->super);
 500                         if (!err)
 501                                 goto restart;
 502                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 503                         return err;
 504                 }
 505         }
 506         rcu_read_unlock();
 507         return 0;
 508 }
 509
 510 /**
 511  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 512  * @inode: inode to process
 513  *
 514  * Does not protect against delegation reclaims, therefore really only safe
 515  * to be called from nfs4_clear_inode().
 516  */
 517 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 518 {
 519         struct nfs_delegation *delegation;
 520
 521         delegation = nfs_inode_detach_delegation(inode);
 522         if (delegation != NULL)
 523                 nfs_do_return_delegation(inode, delegation, 1);
 524 }
 525
 526 /**
 527  * nfs_inode_return_delegation - synchronously return a delegation
 528  * @inode: inode to process
 529  *
 530  * This routine will always flush any dirty data to disk on the
 531  * assumption that if we need to return the delegation, then
 532  * we should stop caching.
 533  *
 534  * Returns zero on success, or a negative errno value.
 535  */
 536 int nfs4_inode_return_delegation(struct inode *inode)
 537 {
 538         struct nfs_inode *nfsi = NFS_I(inode);
 539         struct nfs_delegation *delegation;
 540         int err = 0;
 541
 542         nfs_wb_all(inode);
 543         delegation = nfs_start_delegation_return(nfsi);
 544         if (delegation != NULL)
 545                 err = nfs_end_delegation_return(inode, delegation, 1);
 546         return err;
 547 }
 548
 549 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 550                 struct nfs_delegation *delegation)
 551 {
 552         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 553         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 554 }
 555
 556 static void nfs_mark_return_delegation(struct nfs_server *server,
 557                 struct nfs_delegation *delegation)
 558 {
 559         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 560         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 561 }
 562
 563 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 564 {
 565         struct nfs_delegation *delegation;
 566         bool ret = false;
 567
 568         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 569                 nfs_mark_return_delegation(server, delegation);
 570                 ret = true;
 571         }
 572         return ret;
 573 }
 574
 575 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 576 {
 577         struct nfs_server *server;
 578
 579         rcu_read_lock();
 580         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 581                 nfs_server_mark_return_all_delegations(server);
 582         rcu_read_unlock();
 583 }
 584
 585 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 586 {
 587         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 588                 nfs4_schedule_state_manager(clp);
 589 }
 590
 591 /**
 592  * nfs_expire_all_delegations
 593  * @clp: client to process
 594  *
 595  */
 596 void nfs_expire_all_delegations(struct nfs_client *clp)
 597 {
 598         nfs_client_mark_return_all_delegations(clp);
 599         nfs_delegation_run_state_manager(clp);
 600 }
 601
 602 /**
 603  * nfs_super_return_all_delegations - return delegations for one superblock
 604  * @sb: sb to process
 605  *
 606  */
 607 void nfs_server_return_all_delegations(struct nfs_server *server)
 608 {
 609         struct nfs_client *clp = server->nfs_client;
 610         bool need_wait;
 611
 612         if (clp == NULL)
 613                 return;
 614
 615         rcu_read_lock();
 616         need_wait = nfs_server_mark_return_all_delegations(server);
 617         rcu_read_unlock();
 618
 619         if (need_wait) {
 620                 nfs4_schedule_state_manager(clp);
 621                 nfs4_wait_clnt_recover(clp);
 622         }
 623 }
 624
 625 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 626                                                  fmode_t flags)
 627 {
 628         struct nfs_delegation *delegation;
 629
 630         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 631                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 632                         continue;
 633                 if (delegation->type & flags)
 634                         nfs_mark_return_if_closed_delegation(server, delegation);
 635         }
 636 }
 637
 638 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 639                                                         fmode_t flags)
 640 {
 641         struct nfs_server *server;
 642
 643         rcu_read_lock();
 644         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 645                 nfs_mark_return_unused_delegation_types(server, flags);
 646         rcu_read_unlock();
 647 }
 648
 649 static void nfs_mark_delegation_revoked(struct nfs_server *server,
 650                 struct nfs_delegation *delegation)
 651 {
 652         set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 653         delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
 654         nfs_mark_return_delegation(server, delegation);
 655 }
 656
 657 static bool nfs_revoke_delegation(struct inode *inode,
 658                 const nfs4_stateid *stateid)
 659 {
 660         struct nfs_delegation *delegation;
 661         nfs4_stateid tmp;
 662         bool ret = false;
 663
 664         rcu_read_lock();
 665         delegation = rcu_dereference(NFS_I(inode)->delegation);
 666         if (delegation == NULL)
 667                 goto out;
 668         if (stateid == NULL) {
 669                 nfs4_stateid_copy(&tmp, &delegation->stateid);
 670                 stateid = &tmp;
 671         } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
 672                 goto out;
 673         nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
 674         ret = true;
 675 out:
 676         rcu_read_unlock();
 677         if (ret)
 678                 nfs_inode_find_state_and_recover(inode, stateid);
 679         return ret;
 680 }
 681
 682 void nfs_remove_bad_delegation(struct inode *inode,
 683                 const nfs4_stateid *stateid)
 684 {
 685         struct nfs_delegation *delegation;
 686
 687         if (!nfs_revoke_delegation(inode, stateid))
 688                 return;
 689         delegation = nfs_inode_detach_delegation(inode);
 690         if (delegation)
 691                 nfs_free_delegation(delegation);
 692 }
 693 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 694
 695 /**
 696  * nfs_expire_unused_delegation_types
 697  * @clp: client to process
 698  * @flags: delegation types to expire
 699  *
 700  */
 701 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 702 {
 703         nfs_client_mark_return_unused_delegation_types(clp, flags);
 704         nfs_delegation_run_state_manager(clp);
 705 }
 706
 707 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 708 {
 709         struct nfs_delegation *delegation;
 710
 711         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 712                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 713                         continue;
 714                 nfs_mark_return_if_closed_delegation(server, delegation);
 715         }
 716 }
 717
 718 /**
 719  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 720  * @clp: nfs_client to process
 721  *
 722  */
 723 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 724 {
 725         struct nfs_server *server;
 726
 727         rcu_read_lock();
 728         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 729                 nfs_mark_return_unreferenced_delegations(server);
 730         rcu_read_unlock();
 731
 732         nfs_delegation_run_state_manager(clp);
 733 }
 734
 735 /**
 736  * nfs_async_inode_return_delegation - asynchronously return a delegation
 737  * @inode: inode to process
 738  * @stateid: state ID information
 739  *
 740  * Returns zero on success, or a negative errno value.
 741  */
 742 int nfs_async_inode_return_delegation(struct inode *inode,
 743                                       const nfs4_stateid *stateid)
 744 {
 745         struct nfs_server *server = NFS_SERVER(inode);
 746         struct nfs_client *clp = server->nfs_client;
 747         struct nfs_delegation *delegation;
 748
 749         rcu_read_lock();
 750         delegation = rcu_dereference(NFS_I(inode)->delegation);
 751         if (delegation == NULL)
 752                 goto out_enoent;
 753         if (stateid != NULL &&
 754             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 755                 goto out_enoent;
 756         nfs_mark_return_delegation(server, delegation);
 757         rcu_read_unlock();
 758
 759         nfs_delegation_run_state_manager(clp);
 760         return 0;
 761 out_enoent:
 762         rcu_read_unlock();
 763         return -ENOENT;
 764 }
 765
 766 static struct inode *
 767 nfs_delegation_find_inode_server(struct nfs_server *server,
 768                                  const struct nfs_fh *fhandle)
 769 {
 770         struct nfs_delegation *delegation;
 771         struct inode *res = NULL;
 772
 773         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 774                 spin_lock(&delegation->lock);
 775                 if (delegation->inode != NULL &&
 776                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 777                         res = igrab(delegation->inode);
 778                 }
 779                 spin_unlock(&delegation->lock);
 780                 if (res != NULL)
 781                         break;
 782         }
 783         return res;
 784 }
 785
 786 /**
 787  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 788  * @clp: client state handle
 789  * @fhandle: filehandle from a delegation recall
 790  *
 791  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 792  * cannot be found.
 793  */
 794 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 795                                         const struct nfs_fh *fhandle)
 796 {
 797         struct nfs_server *server;
 798         struct inode *res = NULL;
 799
 800         rcu_read_lock();
 801         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 802                 res = nfs_delegation_find_inode_server(server, fhandle);
 803                 if (res != NULL)
 804                         break;
 805         }
 806         rcu_read_unlock();
 807         return res;
 808 }
 809
 810 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 811 {
 812         struct nfs_delegation *delegation;
 813
 814         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 815                 /*
 816                  * If the delegation may have been admin revoked, then we
 817                  * cannot reclaim it.
 818                  */
 819                 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
 820                         continue;
 821                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 822         }
 823 }
 824
 825 /**
 826  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 827  * @clp: nfs_client to process
 828  *
 829  */
 830 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 831 {
 832         struct nfs_server *server;
 833
 834         rcu_read_lock();
 835         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 836                 nfs_delegation_mark_reclaim_server(server);
 837         rcu_read_unlock();
 838 }
 839
 840 /**
 841  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 842  * @clp: nfs_client to process
 843  *
 844  */
 845 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 846 {
 847         struct nfs_delegation *delegation;
 848         struct nfs_server *server;
 849         struct inode *inode;
 850
 851 restart:
 852         rcu_read_lock();
 853         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 854                 list_for_each_entry_rcu(delegation, &server->delegations,
 855                                                                 super_list) {
 856                         if (test_bit(NFS_DELEGATION_RETURNING,
 857                                                 &delegation->flags))
 858                                 continue;
 859                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 860                                                 &delegation->flags) == 0)
 861                                 continue;
 862                         if (!nfs_sb_active(server->super))
 863                                 continue;
 864                         inode = nfs_delegation_grab_inode(delegation);
 865                         if (inode == NULL) {
 866                                 rcu_read_unlock();
 867                                 nfs_sb_deactive(server->super);
 868                                 goto restart;
 869                         }
 870                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 871                         rcu_read_unlock();
 872                         if (delegation != NULL) {
 873                                 delegation = nfs_detach_delegation(NFS_I(inode),
 874                                         delegation, server);
 875                                 if (delegation != NULL)
 876                                         nfs_free_delegation(delegation);
 877                         }
 878                         iput(inode);
 879                         nfs_sb_deactive(server->super);
 880                         goto restart;
 881                 }
 882         }
 883         rcu_read_unlock();
 884 }
 885
 886 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
 887 {
 888         return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
 889                                 BIT(NFS4CLNT_LEASE_EXPIRED) |
 890                                 BIT(NFS4CLNT_SESSION_RESET))) != 0;
 891 }
 892
 893 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
 894             struct nfs_delegation *delegation)
 895 {
 896         if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
 897                 return;
 898         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 899         set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 900         set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
 901 }
 902
 903 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
 904                 struct inode *inode)
 905 {
 906         struct nfs_delegation *delegation;
 907
 908         rcu_read_lock();
 909         delegation = rcu_dereference(NFS_I(inode)->delegation);
 910         if (delegation)
 911                 nfs_mark_test_expired_delegation(server, delegation);
 912         rcu_read_unlock();
 913
 914 }
 915
 916 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
 917 {
 918         struct nfs_delegation *delegation;
 919
 920         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
 921                 nfs_mark_test_expired_delegation(server, delegation);
 922 }
 923
 924 /**
 925  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
 926  * @clp: nfs_client to process
 927  *
 928  * Iterates through all the delegations associated with this server and
 929  * marks them as needing to be checked for validity.
 930  */
 931 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
 932 {
 933         struct nfs_server *server;
 934
 935         rcu_read_lock();
 936         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 937                 nfs_delegation_mark_test_expired_server(server);
 938         rcu_read_unlock();
 939 }
 940
 941 /**
 942  * nfs_reap_expired_delegations - reap expired delegations
 943  * @clp: nfs_client to process
 944  *
 945  * Iterates through all the delegations associated with this server and
 946  * checks if they have may have been revoked. This function is usually
 947  * expected to be called in cases where the server may have lost its
 948  * lease.
 949  */
 950 void nfs_reap_expired_delegations(struct nfs_client *clp)
 951 {
 952         const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
 953         struct nfs_delegation *delegation;
 954         struct nfs_server *server;
 955         struct inode *inode;
 956         struct rpc_cred *cred;
 957         nfs4_stateid stateid;
 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_RETURNING,
 965                                                 &delegation->flags))
 966                                 continue;
 967                         if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
 968                                                 &delegation->flags) == 0)
 969                                 continue;
 970                         if (!nfs_sb_active(server->super))
 971                                 continue;
 972                         inode = nfs_delegation_grab_inode(delegation);
 973                         if (inode == NULL) {
 974                                 rcu_read_unlock();
 975                                 nfs_sb_deactive(server->super);
 976                                 goto restart;
 977                         }
 978                         cred = get_rpccred_rcu(delegation->cred);
 979                         nfs4_stateid_copy(&stateid, &delegation->stateid);
 980                         clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 981                         rcu_read_unlock();
 982                         if (cred != NULL &&
 983                             ops->test_and_free_expired(server, &stateid, cred) < 0) {
 984                                 nfs_revoke_delegation(inode, &stateid);
 985                                 nfs_inode_find_state_and_recover(inode, &stateid);
 986                         }
 987                         put_rpccred(cred);
 988                         if (nfs4_server_rebooted(clp)) {
 989                                 nfs_inode_mark_test_expired_delegation(server,inode);
 990                                 iput(inode);
 991                                 nfs_sb_deactive(server->super);
 992                                 return;
 993                         }
 994                         iput(inode);
 995                         nfs_sb_deactive(server->super);
 996                         goto restart;
 997                 }
 998         }
 999         rcu_read_unlock();
1000 }
1001
1002 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1003                 const nfs4_stateid *stateid)
1004 {
1005         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1006         struct nfs_delegation *delegation;
1007         bool found = false;
1008
1009         rcu_read_lock();
1010         delegation = rcu_dereference(NFS_I(inode)->delegation);
1011         if (delegation &&
1012             nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1013                 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1014                 found = true;
1015         }
1016         rcu_read_unlock();
1017         if (found)
1018                 nfs4_schedule_state_manager(clp);
1019 }
1020
1021 /**
1022  * nfs_delegations_present - check for existence of delegations
1023  * @clp: client state handle
1024  *
1025  * Returns one if there are any nfs_delegation structures attached
1026  * to this nfs_client.
1027  */
1028 int nfs_delegations_present(struct nfs_client *clp)
1029 {
1030         struct nfs_server *server;
1031         int ret = 0;
1032
1033         rcu_read_lock();
1034         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1035                 if (!list_empty(&server->delegations)) {
1036                         ret = 1;
1037                         break;
1038                 }
1039         rcu_read_unlock();
1040         return ret;
1041 }
1042
1043 /**
1044  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1045  * @inode: inode to check
1046  * @flags: delegation type requirement
1047  * @dst: stateid data structure to fill in
1048  * @cred: optional argument to retrieve credential
1049  *
1050  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1051  * otherwise "false" is returned.
1052  */
1053 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1054                 nfs4_stateid *dst, struct rpc_cred **cred)
1055 {
1056         struct nfs_inode *nfsi = NFS_I(inode);
1057         struct nfs_delegation *delegation;
1058         bool ret;
1059
1060         flags &= FMODE_READ|FMODE_WRITE;
1061         rcu_read_lock();
1062         delegation = rcu_dereference(nfsi->delegation);
1063         ret = nfs4_is_valid_delegation(delegation, flags);
1064         if (ret) {
1065                 nfs4_stateid_copy(dst, &delegation->stateid);
1066                 nfs_mark_delegation_referenced(delegation);
1067                 if (cred)
1068                         *cred = get_rpccred(delegation->cred);
1069         }
1070         rcu_read_unlock();
1071         return ret;
1072 }
1073
1074 /**
1075  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1076  * @inode: inode to check
1077  *
1078  * This function checks the number of outstanding writes to the file
1079  * against the delegation 'space_limit' field to see if
1080  * the spec requires us to flush the file on close.
1081  */
1082 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1083 {
1084         struct nfs_inode *nfsi = NFS_I(inode);
1085         struct nfs_delegation *delegation;
1086         bool ret = true;
1087
1088         rcu_read_lock();
1089         delegation = rcu_dereference(nfsi->delegation);
1090         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1091                 goto out;
1092         if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1093                 ret = false;
1094 out:
1095         rcu_read_unlock();
1096         return ret;
1097 }