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
  24 static void nfs_free_delegation(struct nfs_delegation *delegation)
  25 {
  26         if (delegation->cred) {
  27                 put_rpccred(delegation->cred);
  28                 delegation->cred = NULL;
  29         }
  30         kfree_rcu(delegation, rcu);
  31 }
  32
  33 /**
  34  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
  35  * @delegation: delegation to process
  36  *
  37  */
  38 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  39 {
  40         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  41 }
  42
  43 /**
  44  * nfs_have_delegation - check if inode has a delegation
  45  * @inode: inode to check
  46  * @flags: delegation types to check for
  47  *
  48  * Returns one if inode has the indicated delegation, otherwise zero.
  49  */
  50 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  51 {
  52         struct nfs_delegation *delegation;
  53         int ret = 0;
  54
  55         flags &= FMODE_READ|FMODE_WRITE;
  56         rcu_read_lock();
  57         delegation = rcu_dereference(NFS_I(inode)->delegation);
  58         if (delegation != NULL && (delegation->type & flags) == flags &&
  59             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
  60                 nfs_mark_delegation_referenced(delegation);
  61                 ret = 1;
  62         }
  63         rcu_read_unlock();
  64         return ret;
  65 }
  66
  67 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
  68 {
  69         struct inode *inode = state->inode;
  70         struct file_lock *fl;
  71         int status = 0;
  72
  73         if (inode->i_flock == NULL)
  74                 goto out;
  75
  76         /* Protect inode->i_flock using the file locks lock */
  77         lock_flocks();
  78         for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
  79                 if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
  80                         continue;
  81                 if (nfs_file_open_context(fl->fl_file) != ctx)
  82                         continue;
  83                 unlock_flocks();
  84                 status = nfs4_lock_delegation_recall(fl, state, stateid);
  85                 if (status < 0)
  86                         goto out;
  87                 lock_flocks();
  88         }
  89         unlock_flocks();
  90 out:
  91         return status;
  92 }
  93
  94 static int nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
  95 {
  96         struct nfs_inode *nfsi = NFS_I(inode);
  97         struct nfs_open_context *ctx;
  98         struct nfs4_state_owner *sp;
  99         struct nfs4_state *state;
 100         unsigned int seq;
 101         int err;
 102
 103 again:
 104         spin_lock(&inode->i_lock);
 105         list_for_each_entry(ctx, &nfsi->open_files, list) {
 106                 state = ctx->state;
 107                 if (state == NULL)
 108                         continue;
 109                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 110                         continue;
 111                 if (!nfs4_valid_open_stateid(state))
 112                         continue;
 113                 if (!nfs4_stateid_match(&state->stateid, stateid))
 114                         continue;
 115                 get_nfs_open_context(ctx);
 116                 spin_unlock(&inode->i_lock);
 117                 sp = state->owner;
 118                 /* Block nfs4_proc_unlck */
 119                 mutex_lock(&sp->so_delegreturn_mutex);
 120                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 121                 err = nfs4_open_delegation_recall(ctx, state, stateid);
 122                 if (!err)
 123                         err = nfs_delegation_claim_locks(ctx, state, stateid);
 124                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 125                         err = -EAGAIN;
 126                 mutex_unlock(&sp->so_delegreturn_mutex);
 127                 put_nfs_open_context(ctx);
 128                 if (err != 0)
 129                         return err;
 130                 goto again;
 131         }
 132         spin_unlock(&inode->i_lock);
 133         return 0;
 134 }
 135
 136 /**
 137  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 138  * @inode: inode to process
 139  * @cred: credential to use for request
 140  * @res: new delegation state from server
 141  *
 142  */
 143 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
 144                                   struct nfs_openres *res)
 145 {
 146         struct nfs_delegation *delegation;
 147         struct rpc_cred *oldcred = NULL;
 148
 149         rcu_read_lock();
 150         delegation = rcu_dereference(NFS_I(inode)->delegation);
 151         if (delegation != NULL) {
 152                 spin_lock(&delegation->lock);
 153                 if (delegation->inode != NULL) {
 154                         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 155                         delegation->type = res->delegation_type;
 156                         delegation->maxsize = res->maxsize;
 157                         oldcred = delegation->cred;
 158                         delegation->cred = get_rpccred(cred);
 159                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 160                                   &delegation->flags);
 161                         NFS_I(inode)->delegation_state = delegation->type;
 162                         spin_unlock(&delegation->lock);
 163                         put_rpccred(oldcred);
 164                         rcu_read_unlock();
 165                 } else {
 166                         /* We appear to have raced with a delegation return. */
 167                         spin_unlock(&delegation->lock);
 168                         rcu_read_unlock();
 169                         nfs_inode_set_delegation(inode, cred, res);
 170                 }
 171         } else {
 172                 rcu_read_unlock();
 173         }
 174 }
 175
 176 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 177 {
 178         int res = 0;
 179
 180         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 181                 res = nfs4_proc_delegreturn(inode,
 182                                 delegation->cred,
 183                                 &delegation->stateid,
 184                                 issync);
 185         nfs_free_delegation(delegation);
 186         return res;
 187 }
 188
 189 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 190 {
 191         struct inode *inode = NULL;
 192
 193         spin_lock(&delegation->lock);
 194         if (delegation->inode != NULL)
 195                 inode = igrab(delegation->inode);
 196         spin_unlock(&delegation->lock);
 197         return inode;
 198 }
 199
 200 static struct nfs_delegation *
 201 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 202 {
 203         struct nfs_delegation *ret = NULL;
 204         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 205
 206         if (delegation == NULL)
 207                 goto out;
 208         spin_lock(&delegation->lock);
 209         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 210                 ret = delegation;
 211         spin_unlock(&delegation->lock);
 212 out:
 213         return ret;
 214 }
 215
 216 static struct nfs_delegation *
 217 nfs_start_delegation_return(struct nfs_inode *nfsi)
 218 {
 219         struct nfs_delegation *delegation;
 220
 221         rcu_read_lock();
 222         delegation = nfs_start_delegation_return_locked(nfsi);
 223         rcu_read_unlock();
 224         return delegation;
 225 }
 226
 227 static void
 228 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 229                 struct nfs_client *clp)
 230 {
 231
 232         spin_lock(&delegation->lock);
 233         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 234         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 235         spin_unlock(&delegation->lock);
 236         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 237 }
 238
 239 static struct nfs_delegation *
 240 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 241                 struct nfs_delegation *delegation,
 242                 struct nfs_client *clp)
 243 {
 244         struct nfs_delegation *deleg_cur =
 245                 rcu_dereference_protected(nfsi->delegation,
 246                                 lockdep_is_held(&clp->cl_lock));
 247
 248         if (deleg_cur == NULL || delegation != deleg_cur)
 249                 return NULL;
 250
 251         spin_lock(&delegation->lock);
 252         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 253         list_del_rcu(&delegation->super_list);
 254         delegation->inode = NULL;
 255         nfsi->delegation_state = 0;
 256         rcu_assign_pointer(nfsi->delegation, NULL);
 257         spin_unlock(&delegation->lock);
 258         return delegation;
 259 }
 260
 261 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 262                 struct nfs_delegation *delegation,
 263                 struct nfs_server *server)
 264 {
 265         struct nfs_client *clp = server->nfs_client;
 266
 267         spin_lock(&clp->cl_lock);
 268         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 269         spin_unlock(&clp->cl_lock);
 270         return delegation;
 271 }
 272
 273 static struct nfs_delegation *
 274 nfs_inode_detach_delegation(struct inode *inode)
 275 {
 276         struct nfs_inode *nfsi = NFS_I(inode);
 277         struct nfs_server *server = NFS_SERVER(inode);
 278         struct nfs_delegation *delegation;
 279
 280         delegation = nfs_start_delegation_return(nfsi);
 281         if (delegation == NULL)
 282                 return NULL;
 283         return nfs_detach_delegation(nfsi, delegation, server);
 284 }
 285
 286 /**
 287  * nfs_inode_set_delegation - set up a delegation on an inode
 288  * @inode: inode to which delegation applies
 289  * @cred: cred to use for subsequent delegation processing
 290  * @res: new delegation state from server
 291  *
 292  * Returns zero on success, or a negative errno value.
 293  */
 294 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 295 {
 296         struct nfs_server *server = NFS_SERVER(inode);
 297         struct nfs_client *clp = server->nfs_client;
 298         struct nfs_inode *nfsi = NFS_I(inode);
 299         struct nfs_delegation *delegation, *old_delegation;
 300         struct nfs_delegation *freeme = NULL;
 301         int status = 0;
 302
 303         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 304         if (delegation == NULL)
 305                 return -ENOMEM;
 306         nfs4_stateid_copy(&delegation->stateid, &res->delegation);
 307         delegation->type = res->delegation_type;
 308         delegation->maxsize = res->maxsize;
 309         delegation->change_attr = inode->i_version;
 310         delegation->cred = get_rpccred(cred);
 311         delegation->inode = inode;
 312         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 313         spin_lock_init(&delegation->lock);
 314
 315         spin_lock(&clp->cl_lock);
 316         old_delegation = rcu_dereference_protected(nfsi->delegation,
 317                                         lockdep_is_held(&clp->cl_lock));
 318         if (old_delegation != NULL) {
 319                 if (nfs4_stateid_match(&delegation->stateid,
 320                                         &old_delegation->stateid) &&
 321                                 delegation->type == old_delegation->type) {
 322                         goto out;
 323                 }
 324                 /*
 325                  * Deal with broken servers that hand out two
 326                  * delegations for the same file.
 327                  * Allow for upgrades to a WRITE delegation, but
 328                  * nothing else.
 329                  */
 330                 dfprintk(FILE, "%s: server %s handed out "
 331                                 "a duplicate delegation!\n",
 332                                 __func__, clp->cl_hostname);
 333                 if (delegation->type == old_delegation->type ||
 334                     !(delegation->type & FMODE_WRITE)) {
 335                         freeme = delegation;
 336                         delegation = NULL;
 337                         goto out;
 338                 }
 339                 freeme = nfs_detach_delegation_locked(nfsi,
 340                                 old_delegation, clp);
 341                 if (freeme == NULL)
 342                         goto out;
 343         }
 344         list_add_rcu(&delegation->super_list, &server->delegations);
 345         nfsi->delegation_state = delegation->type;
 346         rcu_assign_pointer(nfsi->delegation, delegation);
 347         delegation = NULL;
 348
 349         /* Ensure we revalidate the attributes and page cache! */
 350         spin_lock(&inode->i_lock);
 351         nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
 352         spin_unlock(&inode->i_lock);
 353
 354 out:
 355         spin_unlock(&clp->cl_lock);
 356         if (delegation != NULL)
 357                 nfs_free_delegation(delegation);
 358         if (freeme != NULL)
 359                 nfs_do_return_delegation(inode, freeme, 0);
 360         return status;
 361 }
 362
 363 /*
 364  * Basic procedure for returning a delegation to the server
 365  */
 366 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 367 {
 368         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 369         struct nfs_inode *nfsi = NFS_I(inode);
 370         int err = 0;
 371
 372         if (delegation == NULL)
 373                 return 0;
 374         do {
 375                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 376                         break;
 377                 err = nfs_delegation_claim_opens(inode, &delegation->stateid);
 378                 if (!issync || err != -EAGAIN)
 379                         break;
 380                 /*
 381                  * Guard against state recovery
 382                  */
 383                 err = nfs4_wait_clnt_recover(clp);
 384         } while (err == 0);
 385
 386         if (err) {
 387                 nfs_abort_delegation_return(delegation, clp);
 388                 goto out;
 389         }
 390         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 391                 goto out;
 392
 393         err = nfs_do_return_delegation(inode, delegation, issync);
 394 out:
 395         return err;
 396 }
 397
 398 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 399 {
 400         bool ret = false;
 401
 402         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 403                 ret = true;
 404         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 405                 struct inode *inode;
 406
 407                 spin_lock(&delegation->lock);
 408                 inode = delegation->inode;
 409                 if (inode && list_empty(&NFS_I(inode)->open_files))
 410                         ret = true;
 411                 spin_unlock(&delegation->lock);
 412         }
 413         return ret;
 414 }
 415
 416 /**
 417  * nfs_client_return_marked_delegations - return previously marked delegations
 418  * @clp: nfs_client to process
 419  *
 420  * Note that this function is designed to be called by the state
 421  * manager thread. For this reason, it cannot flush the dirty data,
 422  * since that could deadlock in case of a state recovery error.
 423  *
 424  * Returns zero on success, or a negative errno value.
 425  */
 426 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 427 {
 428         struct nfs_delegation *delegation;
 429         struct nfs_server *server;
 430         struct inode *inode;
 431         int err = 0;
 432
 433 restart:
 434         rcu_read_lock();
 435         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 436                 list_for_each_entry_rcu(delegation, &server->delegations,
 437                                                                 super_list) {
 438                         if (!nfs_delegation_need_return(delegation))
 439                                 continue;
 440                         inode = nfs_delegation_grab_inode(delegation);
 441                         if (inode == NULL)
 442                                 continue;
 443                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 444                         rcu_read_unlock();
 445
 446                         err = nfs_end_delegation_return(inode, delegation, 0);
 447                         iput(inode);
 448                         if (!err)
 449                                 goto restart;
 450                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 451                         return err;
 452                 }
 453         }
 454         rcu_read_unlock();
 455         return 0;
 456 }
 457
 458 /**
 459  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 460  * @inode: inode to process
 461  *
 462  * Does not protect against delegation reclaims, therefore really only safe
 463  * to be called from nfs4_clear_inode().
 464  */
 465 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 466 {
 467         struct nfs_delegation *delegation;
 468
 469         delegation = nfs_inode_detach_delegation(inode);
 470         if (delegation != NULL)
 471                 nfs_do_return_delegation(inode, delegation, 0);
 472 }
 473
 474 /**
 475  * nfs_inode_return_delegation - synchronously return a delegation
 476  * @inode: inode to process
 477  *
 478  * This routine will always flush any dirty data to disk on the
 479  * assumption that if we need to return the delegation, then
 480  * we should stop caching.
 481  *
 482  * Returns zero on success, or a negative errno value.
 483  */
 484 int nfs4_inode_return_delegation(struct inode *inode)
 485 {
 486         struct nfs_inode *nfsi = NFS_I(inode);
 487         struct nfs_delegation *delegation;
 488         int err = 0;
 489
 490         nfs_wb_all(inode);
 491         delegation = nfs_start_delegation_return(nfsi);
 492         if (delegation != NULL)
 493                 err = nfs_end_delegation_return(inode, delegation, 1);
 494         return err;
 495 }
 496
 497 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 498                 struct nfs_delegation *delegation)
 499 {
 500         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 501         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 502 }
 503
 504 static void nfs_mark_return_delegation(struct nfs_server *server,
 505                 struct nfs_delegation *delegation)
 506 {
 507         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 508         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 509 }
 510
 511 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 512 {
 513         struct nfs_delegation *delegation;
 514         bool ret = false;
 515
 516         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 517                 nfs_mark_return_delegation(server, delegation);
 518                 ret = true;
 519         }
 520         return ret;
 521 }
 522
 523 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 524 {
 525         struct nfs_server *server;
 526
 527         rcu_read_lock();
 528         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 529                 nfs_server_mark_return_all_delegations(server);
 530         rcu_read_unlock();
 531 }
 532
 533 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 534 {
 535         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 536                 nfs4_schedule_state_manager(clp);
 537 }
 538
 539 /**
 540  * nfs_expire_all_delegations
 541  * @clp: client to process
 542  *
 543  */
 544 void nfs_expire_all_delegations(struct nfs_client *clp)
 545 {
 546         nfs_client_mark_return_all_delegations(clp);
 547         nfs_delegation_run_state_manager(clp);
 548 }
 549
 550 /**
 551  * nfs_super_return_all_delegations - return delegations for one superblock
 552  * @sb: sb to process
 553  *
 554  */
 555 void nfs_server_return_all_delegations(struct nfs_server *server)
 556 {
 557         struct nfs_client *clp = server->nfs_client;
 558         bool need_wait;
 559
 560         if (clp == NULL)
 561                 return;
 562
 563         rcu_read_lock();
 564         need_wait = nfs_server_mark_return_all_delegations(server);
 565         rcu_read_unlock();
 566
 567         if (need_wait) {
 568                 nfs4_schedule_state_manager(clp);
 569                 nfs4_wait_clnt_recover(clp);
 570         }
 571 }
 572
 573 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 574                                                  fmode_t flags)
 575 {
 576         struct nfs_delegation *delegation;
 577
 578         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 579                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 580                         continue;
 581                 if (delegation->type & flags)
 582                         nfs_mark_return_if_closed_delegation(server, delegation);
 583         }
 584 }
 585
 586 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 587                                                         fmode_t flags)
 588 {
 589         struct nfs_server *server;
 590
 591         rcu_read_lock();
 592         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 593                 nfs_mark_return_unused_delegation_types(server, flags);
 594         rcu_read_unlock();
 595 }
 596
 597 static void nfs_revoke_delegation(struct inode *inode)
 598 {
 599         struct nfs_delegation *delegation;
 600         rcu_read_lock();
 601         delegation = rcu_dereference(NFS_I(inode)->delegation);
 602         if (delegation != NULL) {
 603                 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 604                 nfs_mark_return_delegation(NFS_SERVER(inode), delegation);
 605         }
 606         rcu_read_unlock();
 607 }
 608
 609 void nfs_remove_bad_delegation(struct inode *inode)
 610 {
 611         struct nfs_delegation *delegation;
 612
 613         nfs_revoke_delegation(inode);
 614         delegation = nfs_inode_detach_delegation(inode);
 615         if (delegation) {
 616                 nfs_inode_find_state_and_recover(inode, &delegation->stateid);
 617                 nfs_free_delegation(delegation);
 618         }
 619 }
 620 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 621
 622 /**
 623  * nfs_expire_unused_delegation_types
 624  * @clp: client to process
 625  * @flags: delegation types to expire
 626  *
 627  */
 628 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 629 {
 630         nfs_client_mark_return_unused_delegation_types(clp, flags);
 631         nfs_delegation_run_state_manager(clp);
 632 }
 633
 634 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 635 {
 636         struct nfs_delegation *delegation;
 637
 638         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 639                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 640                         continue;
 641                 nfs_mark_return_if_closed_delegation(server, delegation);
 642         }
 643 }
 644
 645 /**
 646  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 647  * @clp: nfs_client to process
 648  *
 649  */
 650 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 651 {
 652         struct nfs_server *server;
 653
 654         rcu_read_lock();
 655         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 656                 nfs_mark_return_unreferenced_delegations(server);
 657         rcu_read_unlock();
 658
 659         nfs_delegation_run_state_manager(clp);
 660 }
 661
 662 /**
 663  * nfs_async_inode_return_delegation - asynchronously return a delegation
 664  * @inode: inode to process
 665  * @stateid: state ID information
 666  *
 667  * Returns zero on success, or a negative errno value.
 668  */
 669 int nfs_async_inode_return_delegation(struct inode *inode,
 670                                       const nfs4_stateid *stateid)
 671 {
 672         struct nfs_server *server = NFS_SERVER(inode);
 673         struct nfs_client *clp = server->nfs_client;
 674         struct nfs_delegation *delegation;
 675
 676         filemap_flush(inode->i_mapping);
 677
 678         rcu_read_lock();
 679         delegation = rcu_dereference(NFS_I(inode)->delegation);
 680         if (delegation == NULL)
 681                 goto out_enoent;
 682
 683         if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 684                 goto out_enoent;
 685         nfs_mark_return_delegation(server, delegation);
 686         rcu_read_unlock();
 687
 688         nfs_delegation_run_state_manager(clp);
 689         return 0;
 690 out_enoent:
 691         rcu_read_unlock();
 692         return -ENOENT;
 693 }
 694
 695 static struct inode *
 696 nfs_delegation_find_inode_server(struct nfs_server *server,
 697                                  const struct nfs_fh *fhandle)
 698 {
 699         struct nfs_delegation *delegation;
 700         struct inode *res = NULL;
 701
 702         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 703                 spin_lock(&delegation->lock);
 704                 if (delegation->inode != NULL &&
 705                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 706                         res = igrab(delegation->inode);
 707                 }
 708                 spin_unlock(&delegation->lock);
 709                 if (res != NULL)
 710                         break;
 711         }
 712         return res;
 713 }
 714
 715 /**
 716  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 717  * @clp: client state handle
 718  * @fhandle: filehandle from a delegation recall
 719  *
 720  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 721  * cannot be found.
 722  */
 723 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 724                                         const struct nfs_fh *fhandle)
 725 {
 726         struct nfs_server *server;
 727         struct inode *res = NULL;
 728
 729         rcu_read_lock();
 730         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 731                 res = nfs_delegation_find_inode_server(server, fhandle);
 732                 if (res != NULL)
 733                         break;
 734         }
 735         rcu_read_unlock();
 736         return res;
 737 }
 738
 739 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 740 {
 741         struct nfs_delegation *delegation;
 742
 743         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
 744                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 745 }
 746
 747 /**
 748  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 749  * @clp: nfs_client to process
 750  *
 751  */
 752 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 753 {
 754         struct nfs_server *server;
 755
 756         rcu_read_lock();
 757         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 758                 nfs_delegation_mark_reclaim_server(server);
 759         rcu_read_unlock();
 760 }
 761
 762 /**
 763  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 764  * @clp: nfs_client to process
 765  *
 766  */
 767 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 768 {
 769         struct nfs_delegation *delegation;
 770         struct nfs_server *server;
 771         struct inode *inode;
 772
 773 restart:
 774         rcu_read_lock();
 775         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 776                 list_for_each_entry_rcu(delegation, &server->delegations,
 777                                                                 super_list) {
 778                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 779                                                 &delegation->flags) == 0)
 780                                 continue;
 781                         inode = nfs_delegation_grab_inode(delegation);
 782                         if (inode == NULL)
 783                                 continue;
 784                         delegation = nfs_detach_delegation(NFS_I(inode),
 785                                         delegation, server);
 786                         rcu_read_unlock();
 787
 788                         if (delegation != NULL)
 789                                 nfs_free_delegation(delegation);
 790                         iput(inode);
 791                         goto restart;
 792                 }
 793         }
 794         rcu_read_unlock();
 795 }
 796
 797 /**
 798  * nfs_delegations_present - check for existence of delegations
 799  * @clp: client state handle
 800  *
 801  * Returns one if there are any nfs_delegation structures attached
 802  * to this nfs_client.
 803  */
 804 int nfs_delegations_present(struct nfs_client *clp)
 805 {
 806         struct nfs_server *server;
 807         int ret = 0;
 808
 809         rcu_read_lock();
 810         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 811                 if (!list_empty(&server->delegations)) {
 812                         ret = 1;
 813                         break;
 814                 }
 815         rcu_read_unlock();
 816         return ret;
 817 }
 818
 819 /**
 820  * nfs4_copy_delegation_stateid - Copy inode's state ID information
 821  * @dst: stateid data structure to fill in
 822  * @inode: inode to check
 823  * @flags: delegation type requirement
 824  *
 825  * Returns "true" and fills in "dst->data" * if inode had a delegation,
 826  * otherwise "false" is returned.
 827  */
 828 bool nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode,
 829                 fmode_t flags)
 830 {
 831         struct nfs_inode *nfsi = NFS_I(inode);
 832         struct nfs_delegation *delegation;
 833         bool ret;
 834
 835         flags &= FMODE_READ|FMODE_WRITE;
 836         rcu_read_lock();
 837         delegation = rcu_dereference(nfsi->delegation);
 838         ret = (delegation != NULL && (delegation->type & flags) == flags);
 839         if (ret) {
 840                 nfs4_stateid_copy(dst, &delegation->stateid);
 841                 nfs_mark_delegation_referenced(delegation);
 842         }
 843         rcu_read_unlock();
 844         return ret;
 845 }