fs/nfs/delegation.c

   1 /*
   2  * linux/fs/nfs/delegation.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFS file delegation management
   7  *
   8  */
   9 #include <linux/completion.h>
  10 #include <linux/kthread.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/iversion.h>
  16
  17 #include <linux/nfs4.h>
  18 #include <linux/nfs_fs.h>
  19 #include <linux/nfs_xdr.h>
  20
  21 #include "nfs4_fs.h"
  22 #include "nfs4session.h"
  23 #include "delegation.h"
  24 #include "internal.h"
  25 #include "nfs4trace.h"
  26
  27 static void nfs_free_delegation(struct nfs_delegation *delegation)
  28 {
  29         if (delegation->cred) {
  30                 put_rpccred(delegation->cred);
  31                 delegation->cred = NULL;
  32         }
  33         kfree_rcu(delegation, rcu);
  34 }
  35
  36 /**
  37  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
  38  * @delegation: delegation to process
  39  *
  40  */
  41 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  42 {
  43         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  44 }
  45
  46 static bool
  47 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
  48                 fmode_t flags)
  49 {
  50         if (delegation != NULL && (delegation->type & flags) == flags &&
  51             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
  52             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
  53                 return true;
  54         return false;
  55 }
  56
  57 static int
  58 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  59 {
  60         struct nfs_delegation *delegation;
  61         int ret = 0;
  62
  63         flags &= FMODE_READ|FMODE_WRITE;
  64         rcu_read_lock();
  65         delegation = rcu_dereference(NFS_I(inode)->delegation);
  66         if (nfs4_is_valid_delegation(delegation, flags)) {
  67                 if (mark)
  68                         nfs_mark_delegation_referenced(delegation);
  69                 ret = 1;
  70         }
  71         rcu_read_unlock();
  72         return ret;
  73 }
  74 /**
  75  * nfs_have_delegation - check if inode has a delegation, mark it
  76  * NFS_DELEGATION_REFERENCED if there is one.
  77  * @inode: inode to check
  78  * @flags: delegation types to check for
  79  *
  80  * Returns one if inode has the indicated delegation, otherwise zero.
  81  */
  82 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  83 {
  84         return nfs4_do_check_delegation(inode, flags, true);
  85 }
  86
  87 /*
  88  * nfs4_check_delegation - check if inode has a delegation, do not mark
  89  * NFS_DELEGATION_REFERENCED if it has one.
  90  */
  91 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
  92 {
  93         return nfs4_do_check_delegation(inode, flags, false);
  94 }
  95
  96 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
  97 {
  98         struct inode *inode = state->inode;
  99         struct file_lock *fl;
 100         struct file_lock_context *flctx = inode->i_flctx;
 101         struct list_head *list;
 102         int status = 0;
 103
 104         if (flctx == NULL)
 105                 goto out;
 106
 107         list = &flctx->flc_posix;
 108         spin_lock(&flctx->flc_lock);
 109 restart:
 110         list_for_each_entry(fl, list, fl_list) {
 111                 if (nfs_file_open_context(fl->fl_file) != ctx)
 112                         continue;
 113                 spin_unlock(&flctx->flc_lock);
 114                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 115                 if (status < 0)
 116                         goto out;
 117                 spin_lock(&flctx->flc_lock);
 118         }
 119         if (list == &flctx->flc_posix) {
 120                 list = &flctx->flc_flock;
 121                 goto restart;
 122         }
 123         spin_unlock(&flctx->flc_lock);
 124 out:
 125         return status;
 126 }
 127
 128 static int nfs_delegation_claim_opens(struct inode *inode,
 129                 const nfs4_stateid *stateid, fmode_t type)
 130 {
 131         struct nfs_inode *nfsi = NFS_I(inode);
 132         struct nfs_open_context *ctx;
 133         struct nfs4_state_owner *sp;
 134         struct nfs4_state *state;
 135         unsigned int seq;
 136         int err;
 137
 138 again:
 139         spin_lock(&inode->i_lock);
 140         list_for_each_entry(ctx, &nfsi->open_files, list) {
 141                 state = ctx->state;
 142                 if (state == NULL)
 143                         continue;
 144                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 145                         continue;
 146                 if (!nfs4_valid_open_stateid(state))
 147                         continue;
 148                 if (!nfs4_stateid_match(&state->stateid, stateid))
 149                         continue;
 150                 get_nfs_open_context(ctx);
 151                 spin_unlock(&inode->i_lock);
 152                 sp = state->owner;
 153                 /* Block nfs4_proc_unlck */
 154                 mutex_lock(&sp->so_delegreturn_mutex);
 155                 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
 156                 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
 157                 if (!err)
 158                         err = nfs_delegation_claim_locks(ctx, state, stateid);
 159                 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
 160                         err = -EAGAIN;
 161                 mutex_unlock(&sp->so_delegreturn_mutex);
 162                 put_nfs_open_context(ctx);
 163                 if (err != 0)
 164                         return err;
 165                 goto again;
 166         }
 167         spin_unlock(&inode->i_lock);
 168         return 0;
 169 }
 170
 171 /**
 172  * nfs_inode_reclaim_delegation - process a delegation reclaim request
 173  * @inode: inode to process
 174  * @cred: credential to use for request
 175  * @type: delegation type
 176  * @stateid: delegation stateid
 177  * @pagemod_limit: write delegation "space_limit"
 178  *
 179  */
 180 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
 181                                   fmode_t type,
 182                                   const nfs4_stateid *stateid,
 183                                   unsigned long pagemod_limit)
 184 {
 185         struct nfs_delegation *delegation;
 186         struct rpc_cred *oldcred = NULL;
 187
 188         rcu_read_lock();
 189         delegation = rcu_dereference(NFS_I(inode)->delegation);
 190         if (delegation != NULL) {
 191                 spin_lock(&delegation->lock);
 192                 if (delegation->inode != NULL) {
 193                         nfs4_stateid_copy(&delegation->stateid, stateid);
 194                         delegation->type = type;
 195                         delegation->pagemod_limit = pagemod_limit;
 196                         oldcred = delegation->cred;
 197                         delegation->cred = get_rpccred(cred);
 198                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 199                                   &delegation->flags);
 200                         spin_unlock(&delegation->lock);
 201                         rcu_read_unlock();
 202                         put_rpccred(oldcred);
 203                         trace_nfs4_reclaim_delegation(inode, type);
 204                         return;
 205                 }
 206                 /* We appear to have raced with a delegation return. */
 207                 spin_unlock(&delegation->lock);
 208         }
 209         rcu_read_unlock();
 210         nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
 211 }
 212
 213 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
 214 {
 215         int res = 0;
 216
 217         if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 218                 res = nfs4_proc_delegreturn(inode,
 219                                 delegation->cred,
 220                                 &delegation->stateid,
 221                                 issync);
 222         nfs_free_delegation(delegation);
 223         return res;
 224 }
 225
 226 static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
 227 {
 228         struct inode *inode = NULL;
 229
 230         spin_lock(&delegation->lock);
 231         if (delegation->inode != NULL)
 232                 inode = igrab(delegation->inode);
 233         spin_unlock(&delegation->lock);
 234         return inode;
 235 }
 236
 237 static struct nfs_delegation *
 238 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 239 {
 240         struct nfs_delegation *ret = NULL;
 241         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 242
 243         if (delegation == NULL)
 244                 goto out;
 245         spin_lock(&delegation->lock);
 246         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 247                 ret = delegation;
 248         spin_unlock(&delegation->lock);
 249 out:
 250         return ret;
 251 }
 252
 253 static struct nfs_delegation *
 254 nfs_start_delegation_return(struct nfs_inode *nfsi)
 255 {
 256         struct nfs_delegation *delegation;
 257
 258         rcu_read_lock();
 259         delegation = nfs_start_delegation_return_locked(nfsi);
 260         rcu_read_unlock();
 261         return delegation;
 262 }
 263
 264 static void
 265 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 266                 struct nfs_client *clp)
 267 {
 268
 269         spin_lock(&delegation->lock);
 270         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 271         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 272         spin_unlock(&delegation->lock);
 273         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 274 }
 275
 276 static struct nfs_delegation *
 277 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 278                 struct nfs_delegation *delegation,
 279                 struct nfs_client *clp)
 280 {
 281         struct nfs_delegation *deleg_cur =
 282                 rcu_dereference_protected(nfsi->delegation,
 283                                 lockdep_is_held(&clp->cl_lock));
 284
 285         if (deleg_cur == NULL || delegation != deleg_cur)
 286                 return NULL;
 287
 288         spin_lock(&delegation->lock);
 289         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 290         list_del_rcu(&delegation->super_list);
 291         delegation->inode = NULL;
 292         rcu_assign_pointer(nfsi->delegation, NULL);
 293         spin_unlock(&delegation->lock);
 294         return delegation;
 295 }
 296
 297 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 298                 struct nfs_delegation *delegation,
 299                 struct nfs_server *server)
 300 {
 301         struct nfs_client *clp = server->nfs_client;
 302
 303         spin_lock(&clp->cl_lock);
 304         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 305         spin_unlock(&clp->cl_lock);
 306         return delegation;
 307 }
 308
 309 static struct nfs_delegation *
 310 nfs_inode_detach_delegation(struct inode *inode)
 311 {
 312         struct nfs_inode *nfsi = NFS_I(inode);
 313         struct nfs_server *server = NFS_SERVER(inode);
 314         struct nfs_delegation *delegation;
 315
 316         delegation = nfs_start_delegation_return(nfsi);
 317         if (delegation == NULL)
 318                 return NULL;
 319         return nfs_detach_delegation(nfsi, delegation, server);
 320 }
 321
 322 static void
 323 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 324                 const struct nfs_delegation *update)
 325 {
 326         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 327                 delegation->stateid.seqid = update->stateid.seqid;
 328                 smp_wmb();
 329                 delegation->type = update->type;
 330         }
 331 }
 332
 333 /**
 334  * nfs_inode_set_delegation - set up a delegation on an inode
 335  * @inode: inode to which delegation applies
 336  * @cred: cred to use for subsequent delegation processing
 337  * @type: delegation type
 338  * @stateid: delegation stateid
 339  * @pagemod_limit: write delegation "space_limit"
 340  *
 341  * Returns zero on success, or a negative errno value.
 342  */
 343 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred,
 344                                   fmode_t type,
 345                                   const nfs4_stateid *stateid,
 346                                   unsigned long pagemod_limit)
 347 {
 348         struct nfs_server *server = NFS_SERVER(inode);
 349         struct nfs_client *clp = server->nfs_client;
 350         struct nfs_inode *nfsi = NFS_I(inode);
 351         struct nfs_delegation *delegation, *old_delegation;
 352         struct nfs_delegation *freeme = NULL;
 353         int status = 0;
 354
 355         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 356         if (delegation == NULL)
 357                 return -ENOMEM;
 358         nfs4_stateid_copy(&delegation->stateid, stateid);
 359         delegation->type = type;
 360         delegation->pagemod_limit = pagemod_limit;
 361         delegation->change_attr = inode_peek_iversion_raw(inode);
 362         delegation->cred = get_rpccred(cred);
 363         delegation->inode = inode;
 364         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 365         spin_lock_init(&delegation->lock);
 366
 367         spin_lock(&clp->cl_lock);
 368         old_delegation = rcu_dereference_protected(nfsi->delegation,
 369                                         lockdep_is_held(&clp->cl_lock));
 370         if (old_delegation != NULL) {
 371                 /* Is this an update of the existing delegation? */
 372                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 373                                         &delegation->stateid)) {
 374                         nfs_update_inplace_delegation(old_delegation,
 375                                         delegation);
 376                         goto out;
 377                 }
 378                 /*
 379                  * Deal with broken servers that hand out two
 380                  * delegations for the same file.
 381                  * Allow for upgrades to a WRITE delegation, but
 382                  * nothing else.
 383                  */
 384                 dfprintk(FILE, "%s: server %s handed out "
 385                                 "a duplicate delegation!\n",
 386                                 __func__, clp->cl_hostname);
 387                 if (delegation->type == old_delegation->type ||
 388                     !(delegation->type & FMODE_WRITE)) {
 389                         freeme = delegation;
 390                         delegation = NULL;
 391                         goto out;
 392                 }
 393                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 394                                         &old_delegation->flags))
 395                         goto out;
 396                 freeme = nfs_detach_delegation_locked(nfsi,
 397                                 old_delegation, clp);
 398                 if (freeme == NULL)
 399                         goto out;
 400         }
 401         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 402         rcu_assign_pointer(nfsi->delegation, delegation);
 403         delegation = NULL;
 404
 405         trace_nfs4_set_delegation(inode, type);
 406
 407         spin_lock(&inode->i_lock);
 408         if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME))
 409                 NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED;
 410         spin_unlock(&inode->i_lock);
 411 out:
 412         spin_unlock(&clp->cl_lock);
 413         if (delegation != NULL)
 414                 nfs_free_delegation(delegation);
 415         if (freeme != NULL)
 416                 nfs_do_return_delegation(inode, freeme, 0);
 417         return status;
 418 }
 419
 420 /*
 421  * Basic procedure for returning a delegation to the server
 422  */
 423 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 424 {
 425         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 426         struct nfs_inode *nfsi = NFS_I(inode);
 427         int err = 0;
 428
 429         if (delegation == NULL)
 430                 return 0;
 431         do {
 432                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 433                         break;
 434                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 435                                 delegation->type);
 436                 if (!issync || err != -EAGAIN)
 437                         break;
 438                 /*
 439                  * Guard against state recovery
 440                  */
 441                 err = nfs4_wait_clnt_recover(clp);
 442         } while (err == 0);
 443
 444         if (err) {
 445                 nfs_abort_delegation_return(delegation, clp);
 446                 goto out;
 447         }
 448         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 449                 goto out;
 450
 451         err = nfs_do_return_delegation(inode, delegation, issync);
 452 out:
 453         return err;
 454 }
 455
 456 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 457 {
 458         bool ret = false;
 459
 460         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 461                 goto out;
 462         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 463                 ret = true;
 464         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 465                 struct inode *inode;
 466
 467                 spin_lock(&delegation->lock);
 468                 inode = delegation->inode;
 469                 if (inode && list_empty(&NFS_I(inode)->open_files))
 470                         ret = true;
 471                 spin_unlock(&delegation->lock);
 472         }
 473 out:
 474         return ret;
 475 }
 476
 477 /**
 478  * nfs_client_return_marked_delegations - return previously marked delegations
 479  * @clp: nfs_client to process
 480  *
 481  * Note that this function is designed to be called by the state
 482  * manager thread. For this reason, it cannot flush the dirty data,
 483  * since that could deadlock in case of a state recovery error.
 484  *
 485  * Returns zero on success, or a negative errno value.
 486  */
 487 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 488 {
 489         struct nfs_delegation *delegation;
 490         struct nfs_delegation *prev;
 491         struct nfs_server *server;
 492         struct inode *inode;
 493         struct inode *place_holder = NULL;
 494         struct nfs_delegation *place_holder_deleg = NULL;
 495         int err = 0;
 496
 497 restart:
 498         /*
 499          * To avoid quadratic looping we hold a reference
 500          * to an inode place_holder.  Each time we restart, we
 501          * list nfs_servers from the server of that inode, and
 502          * delegation in the server from the delegations of that
 503          * inode.
 504          * prev is an RCU-protected pointer to a delegation which
 505          * wasn't marked for return and might be a good choice for
 506          * the next place_holder.
 507          */
 508         rcu_read_lock();
 509         prev = NULL;
 510         if (place_holder)
 511                 server = NFS_SERVER(place_holder);
 512         else
 513                 server = list_entry_rcu(clp->cl_superblocks.next,
 514                                         struct nfs_server, client_link);
 515         list_for_each_entry_from_rcu(server, &clp->cl_superblocks, client_link) {
 516                 delegation = NULL;
 517                 if (place_holder && server == NFS_SERVER(place_holder))
 518                         delegation = rcu_dereference(NFS_I(place_holder)->delegation);
 519                 if (!delegation || delegation != place_holder_deleg)
 520                         delegation = list_entry_rcu(server->delegations.next,
 521                                                     struct nfs_delegation, super_list);
 522                 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
 523                         struct inode *to_put = NULL;
 524
 525                         if (!nfs_delegation_need_return(delegation)) {
 526                                 prev = delegation;
 527                                 continue;
 528                         }
 529                         if (!nfs_sb_active(server->super))
 530                                 break; /* continue in outer loop */
 531
 532                         if (prev) {
 533                                 struct inode *tmp;
 534
 535                                 tmp = nfs_delegation_grab_inode(prev);
 536                                 if (tmp) {
 537                                         to_put = place_holder;
 538                                         place_holder = tmp;
 539                                         place_holder_deleg = prev;
 540                                 }
 541                         }
 542
 543                         inode = nfs_delegation_grab_inode(delegation);
 544                         if (inode == NULL) {
 545                                 rcu_read_unlock();
 546                                 if (to_put)
 547                                         iput(to_put);
 548                                 nfs_sb_deactive(server->super);
 549                                 goto restart;
 550                         }
 551                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 552                         rcu_read_unlock();
 553
 554                         if (to_put)
 555                                 iput(to_put);
 556
 557                         err = nfs_end_delegation_return(inode, delegation, 0);
 558                         iput(inode);
 559                         nfs_sb_deactive(server->super);
 560                         cond_resched();
 561                         if (!err)
 562                                 goto restart;
 563                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 564                         if (place_holder)
 565                                 iput(place_holder);
 566                         return err;
 567                 }
 568         }
 569         rcu_read_unlock();
 570         if (place_holder)
 571                 iput(place_holder);
 572         return 0;
 573 }
 574
 575 /**
 576  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 577  * @inode: inode to process
 578  *
 579  * Does not protect against delegation reclaims, therefore really only safe
 580  * to be called from nfs4_clear_inode().
 581  */
 582 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 583 {
 584         struct nfs_delegation *delegation;
 585
 586         delegation = nfs_inode_detach_delegation(inode);
 587         if (delegation != NULL)
 588                 nfs_do_return_delegation(inode, delegation, 1);
 589 }
 590
 591 /**
 592  * nfs_inode_return_delegation - synchronously return a delegation
 593  * @inode: inode to process
 594  *
 595  * This routine will always flush any dirty data to disk on the
 596  * assumption that if we need to return the delegation, then
 597  * we should stop caching.
 598  *
 599  * Returns zero on success, or a negative errno value.
 600  */
 601 int nfs4_inode_return_delegation(struct inode *inode)
 602 {
 603         struct nfs_inode *nfsi = NFS_I(inode);
 604         struct nfs_delegation *delegation;
 605         int err = 0;
 606
 607         nfs_wb_all(inode);
 608         delegation = nfs_start_delegation_return(nfsi);
 609         if (delegation != NULL)
 610                 err = nfs_end_delegation_return(inode, delegation, 1);
 611         return err;
 612 }
 613
 614 /**
 615  * nfs4_inode_make_writeable
 616  * @inode: pointer to inode
 617  *
 618  * Make the inode writeable by returning the delegation if necessary
 619  *
 620  * Returns zero on success, or a negative errno value.
 621  */
 622 int nfs4_inode_make_writeable(struct inode *inode)
 623 {
 624         if (!nfs4_has_session(NFS_SERVER(inode)->nfs_client) ||
 625             !nfs4_check_delegation(inode, FMODE_WRITE))
 626                 return nfs4_inode_return_delegation(inode);
 627         return 0;
 628 }
 629
 630 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 631                 struct nfs_delegation *delegation)
 632 {
 633         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 634         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 635 }
 636
 637 static void nfs_mark_return_delegation(struct nfs_server *server,
 638                 struct nfs_delegation *delegation)
 639 {
 640         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 641         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 642 }
 643
 644 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 645 {
 646         struct nfs_delegation *delegation;
 647         bool ret = false;
 648
 649         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 650                 nfs_mark_return_delegation(server, delegation);
 651                 ret = true;
 652         }
 653         return ret;
 654 }
 655
 656 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 657 {
 658         struct nfs_server *server;
 659
 660         rcu_read_lock();
 661         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 662                 nfs_server_mark_return_all_delegations(server);
 663         rcu_read_unlock();
 664 }
 665
 666 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 667 {
 668         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 669                 nfs4_schedule_state_manager(clp);
 670 }
 671
 672 /**
 673  * nfs_expire_all_delegations
 674  * @clp: client to process
 675  *
 676  */
 677 void nfs_expire_all_delegations(struct nfs_client *clp)
 678 {
 679         nfs_client_mark_return_all_delegations(clp);
 680         nfs_delegation_run_state_manager(clp);
 681 }
 682
 683 /**
 684  * nfs_super_return_all_delegations - return delegations for one superblock
 685  * @sb: sb to process
 686  *
 687  */
 688 void nfs_server_return_all_delegations(struct nfs_server *server)
 689 {
 690         struct nfs_client *clp = server->nfs_client;
 691         bool need_wait;
 692
 693         if (clp == NULL)
 694                 return;
 695
 696         rcu_read_lock();
 697         need_wait = nfs_server_mark_return_all_delegations(server);
 698         rcu_read_unlock();
 699
 700         if (need_wait) {
 701                 nfs4_schedule_state_manager(clp);
 702                 nfs4_wait_clnt_recover(clp);
 703         }
 704 }
 705
 706 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 707                                                  fmode_t flags)
 708 {
 709         struct nfs_delegation *delegation;
 710
 711         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 712                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 713                         continue;
 714                 if (delegation->type & flags)
 715                         nfs_mark_return_if_closed_delegation(server, delegation);
 716         }
 717 }
 718
 719 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 720                                                         fmode_t flags)
 721 {
 722         struct nfs_server *server;
 723
 724         rcu_read_lock();
 725         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 726                 nfs_mark_return_unused_delegation_types(server, flags);
 727         rcu_read_unlock();
 728 }
 729
 730 static void nfs_mark_delegation_revoked(struct nfs_server *server,
 731                 struct nfs_delegation *delegation)
 732 {
 733         set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 734         delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
 735         nfs_mark_return_delegation(server, delegation);
 736 }
 737
 738 static bool nfs_revoke_delegation(struct inode *inode,
 739                 const nfs4_stateid *stateid)
 740 {
 741         struct nfs_delegation *delegation;
 742         nfs4_stateid tmp;
 743         bool ret = false;
 744
 745         rcu_read_lock();
 746         delegation = rcu_dereference(NFS_I(inode)->delegation);
 747         if (delegation == NULL)
 748                 goto out;
 749         if (stateid == NULL) {
 750                 nfs4_stateid_copy(&tmp, &delegation->stateid);
 751                 stateid = &tmp;
 752         } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
 753                 goto out;
 754         nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
 755         ret = true;
 756 out:
 757         rcu_read_unlock();
 758         if (ret)
 759                 nfs_inode_find_state_and_recover(inode, stateid);
 760         return ret;
 761 }
 762
 763 void nfs_remove_bad_delegation(struct inode *inode,
 764                 const nfs4_stateid *stateid)
 765 {
 766         struct nfs_delegation *delegation;
 767
 768         if (!nfs_revoke_delegation(inode, stateid))
 769                 return;
 770         delegation = nfs_inode_detach_delegation(inode);
 771         if (delegation)
 772                 nfs_free_delegation(delegation);
 773 }
 774 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 775
 776 /**
 777  * nfs_expire_unused_delegation_types
 778  * @clp: client to process
 779  * @flags: delegation types to expire
 780  *
 781  */
 782 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 783 {
 784         nfs_client_mark_return_unused_delegation_types(clp, flags);
 785         nfs_delegation_run_state_manager(clp);
 786 }
 787
 788 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 789 {
 790         struct nfs_delegation *delegation;
 791
 792         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 793                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 794                         continue;
 795                 nfs_mark_return_if_closed_delegation(server, delegation);
 796         }
 797 }
 798
 799 /**
 800  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 801  * @clp: nfs_client to process
 802  *
 803  */
 804 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 805 {
 806         struct nfs_server *server;
 807
 808         rcu_read_lock();
 809         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 810                 nfs_mark_return_unreferenced_delegations(server);
 811         rcu_read_unlock();
 812
 813         nfs_delegation_run_state_manager(clp);
 814 }
 815
 816 /**
 817  * nfs_async_inode_return_delegation - asynchronously return a delegation
 818  * @inode: inode to process
 819  * @stateid: state ID information
 820  *
 821  * Returns zero on success, or a negative errno value.
 822  */
 823 int nfs_async_inode_return_delegation(struct inode *inode,
 824                                       const nfs4_stateid *stateid)
 825 {
 826         struct nfs_server *server = NFS_SERVER(inode);
 827         struct nfs_client *clp = server->nfs_client;
 828         struct nfs_delegation *delegation;
 829
 830         rcu_read_lock();
 831         delegation = rcu_dereference(NFS_I(inode)->delegation);
 832         if (delegation == NULL)
 833                 goto out_enoent;
 834         if (stateid != NULL &&
 835             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 836                 goto out_enoent;
 837         nfs_mark_return_delegation(server, delegation);
 838         rcu_read_unlock();
 839
 840         nfs_delegation_run_state_manager(clp);
 841         return 0;
 842 out_enoent:
 843         rcu_read_unlock();
 844         return -ENOENT;
 845 }
 846
 847 static struct inode *
 848 nfs_delegation_find_inode_server(struct nfs_server *server,
 849                                  const struct nfs_fh *fhandle)
 850 {
 851         struct nfs_delegation *delegation;
 852         struct inode *res = NULL;
 853
 854         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 855                 spin_lock(&delegation->lock);
 856                 if (delegation->inode != NULL &&
 857                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 858                         res = igrab(delegation->inode);
 859                         spin_unlock(&delegation->lock);
 860                         if (res != NULL)
 861                                 return res;
 862                         return ERR_PTR(-EAGAIN);
 863                 }
 864                 spin_unlock(&delegation->lock);
 865         }
 866         return ERR_PTR(-ENOENT);
 867 }
 868
 869 /**
 870  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 871  * @clp: client state handle
 872  * @fhandle: filehandle from a delegation recall
 873  *
 874  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 875  * cannot be found.
 876  */
 877 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 878                                         const struct nfs_fh *fhandle)
 879 {
 880         struct nfs_server *server;
 881         struct inode *res;
 882
 883         rcu_read_lock();
 884         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 885                 res = nfs_delegation_find_inode_server(server, fhandle);
 886                 if (res != ERR_PTR(-ENOENT))
 887                         return res;
 888         }
 889         rcu_read_unlock();
 890         return ERR_PTR(-ENOENT);
 891 }
 892
 893 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 894 {
 895         struct nfs_delegation *delegation;
 896
 897         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 898                 /*
 899                  * If the delegation may have been admin revoked, then we
 900                  * cannot reclaim it.
 901                  */
 902                 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
 903                         continue;
 904                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 905         }
 906 }
 907
 908 /**
 909  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 910  * @clp: nfs_client to process
 911  *
 912  */
 913 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 914 {
 915         struct nfs_server *server;
 916
 917         rcu_read_lock();
 918         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 919                 nfs_delegation_mark_reclaim_server(server);
 920         rcu_read_unlock();
 921 }
 922
 923 /**
 924  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 925  * @clp: nfs_client to process
 926  *
 927  */
 928 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 929 {
 930         struct nfs_delegation *delegation;
 931         struct nfs_server *server;
 932         struct inode *inode;
 933
 934 restart:
 935         rcu_read_lock();
 936         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 937                 list_for_each_entry_rcu(delegation, &server->delegations,
 938                                                                 super_list) {
 939                         if (test_bit(NFS_DELEGATION_RETURNING,
 940                                                 &delegation->flags))
 941                                 continue;
 942                         if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
 943                                                 &delegation->flags) == 0)
 944                                 continue;
 945                         if (!nfs_sb_active(server->super))
 946                                 break; /* continue in outer loop */
 947                         inode = nfs_delegation_grab_inode(delegation);
 948                         if (inode == NULL) {
 949                                 rcu_read_unlock();
 950                                 nfs_sb_deactive(server->super);
 951                                 goto restart;
 952                         }
 953                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 954                         rcu_read_unlock();
 955                         if (delegation != NULL) {
 956                                 delegation = nfs_detach_delegation(NFS_I(inode),
 957                                         delegation, server);
 958                                 if (delegation != NULL)
 959                                         nfs_free_delegation(delegation);
 960                         }
 961                         iput(inode);
 962                         nfs_sb_deactive(server->super);
 963                         cond_resched();
 964                         goto restart;
 965                 }
 966         }
 967         rcu_read_unlock();
 968 }
 969
 970 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
 971 {
 972         return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
 973                                 BIT(NFS4CLNT_LEASE_EXPIRED) |
 974                                 BIT(NFS4CLNT_SESSION_RESET))) != 0;
 975 }
 976
 977 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
 978             struct nfs_delegation *delegation)
 979 {
 980         if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
 981                 return;
 982         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 983         set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 984         set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
 985 }
 986
 987 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
 988                 struct inode *inode)
 989 {
 990         struct nfs_delegation *delegation;
 991
 992         rcu_read_lock();
 993         delegation = rcu_dereference(NFS_I(inode)->delegation);
 994         if (delegation)
 995                 nfs_mark_test_expired_delegation(server, delegation);
 996         rcu_read_unlock();
 997
 998 }
 999
1000 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1001 {
1002         struct nfs_delegation *delegation;
1003
1004         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1005                 nfs_mark_test_expired_delegation(server, delegation);
1006 }
1007
1008 /**
1009  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1010  * @clp: nfs_client to process
1011  *
1012  * Iterates through all the delegations associated with this server and
1013  * marks them as needing to be checked for validity.
1014  */
1015 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1016 {
1017         struct nfs_server *server;
1018
1019         rcu_read_lock();
1020         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1021                 nfs_delegation_mark_test_expired_server(server);
1022         rcu_read_unlock();
1023 }
1024
1025 /**
1026  * nfs_reap_expired_delegations - reap expired delegations
1027  * @clp: nfs_client to process
1028  *
1029  * Iterates through all the delegations associated with this server and
1030  * checks if they have may have been revoked. This function is usually
1031  * expected to be called in cases where the server may have lost its
1032  * lease.
1033  */
1034 void nfs_reap_expired_delegations(struct nfs_client *clp)
1035 {
1036         const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
1037         struct nfs_delegation *delegation;
1038         struct nfs_server *server;
1039         struct inode *inode;
1040         struct rpc_cred *cred;
1041         nfs4_stateid stateid;
1042
1043 restart:
1044         rcu_read_lock();
1045         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1046                 list_for_each_entry_rcu(delegation, &server->delegations,
1047                                                                 super_list) {
1048                         if (test_bit(NFS_DELEGATION_RETURNING,
1049                                                 &delegation->flags))
1050                                 continue;
1051                         if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
1052                                                 &delegation->flags) == 0)
1053                                 continue;
1054                         if (!nfs_sb_active(server->super))
1055                                 break; /* continue in outer loop */
1056                         inode = nfs_delegation_grab_inode(delegation);
1057                         if (inode == NULL) {
1058                                 rcu_read_unlock();
1059                                 nfs_sb_deactive(server->super);
1060                                 goto restart;
1061                         }
1062                         cred = get_rpccred_rcu(delegation->cred);
1063                         nfs4_stateid_copy(&stateid, &delegation->stateid);
1064                         clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1065                         rcu_read_unlock();
1066                         if (cred != NULL &&
1067                             ops->test_and_free_expired(server, &stateid, cred) < 0) {
1068                                 nfs_revoke_delegation(inode, &stateid);
1069                                 nfs_inode_find_state_and_recover(inode, &stateid);
1070                         }
1071                         put_rpccred(cred);
1072                         if (nfs4_server_rebooted(clp)) {
1073                                 nfs_inode_mark_test_expired_delegation(server,inode);
1074                                 iput(inode);
1075                                 nfs_sb_deactive(server->super);
1076                                 return;
1077                         }
1078                         iput(inode);
1079                         nfs_sb_deactive(server->super);
1080                         cond_resched();
1081                         goto restart;
1082                 }
1083         }
1084         rcu_read_unlock();
1085 }
1086
1087 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1088                 const nfs4_stateid *stateid)
1089 {
1090         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1091         struct nfs_delegation *delegation;
1092         bool found = false;
1093
1094         rcu_read_lock();
1095         delegation = rcu_dereference(NFS_I(inode)->delegation);
1096         if (delegation &&
1097             nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1098                 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1099                 found = true;
1100         }
1101         rcu_read_unlock();
1102         if (found)
1103                 nfs4_schedule_state_manager(clp);
1104 }
1105
1106 /**
1107  * nfs_delegations_present - check for existence of delegations
1108  * @clp: client state handle
1109  *
1110  * Returns one if there are any nfs_delegation structures attached
1111  * to this nfs_client.
1112  */
1113 int nfs_delegations_present(struct nfs_client *clp)
1114 {
1115         struct nfs_server *server;
1116         int ret = 0;
1117
1118         rcu_read_lock();
1119         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1120                 if (!list_empty(&server->delegations)) {
1121                         ret = 1;
1122                         break;
1123                 }
1124         rcu_read_unlock();
1125         return ret;
1126 }
1127
1128 /**
1129  * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1130  * @dst: stateid to refresh
1131  * @inode: inode to check
1132  *
1133  * Returns "true" and updates "dst->seqid" * if inode had a delegation
1134  * that matches our delegation stateid. Otherwise "false" is returned.
1135  */
1136 bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1137 {
1138         struct nfs_delegation *delegation;
1139         bool ret = false;
1140         if (!inode)
1141                 goto out;
1142
1143         rcu_read_lock();
1144         delegation = rcu_dereference(NFS_I(inode)->delegation);
1145         if (delegation != NULL &&
1146             nfs4_stateid_match_other(dst, &delegation->stateid)) {
1147                 dst->seqid = delegation->stateid.seqid;
1148                 return ret;
1149         }
1150         rcu_read_unlock();
1151 out:
1152         return ret;
1153 }
1154
1155 /**
1156  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1157  * @inode: inode to check
1158  * @flags: delegation type requirement
1159  * @dst: stateid data structure to fill in
1160  * @cred: optional argument to retrieve credential
1161  *
1162  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1163  * otherwise "false" is returned.
1164  */
1165 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1166                 nfs4_stateid *dst, struct rpc_cred **cred)
1167 {
1168         struct nfs_inode *nfsi = NFS_I(inode);
1169         struct nfs_delegation *delegation;
1170         bool ret;
1171
1172         flags &= FMODE_READ|FMODE_WRITE;
1173         rcu_read_lock();
1174         delegation = rcu_dereference(nfsi->delegation);
1175         ret = nfs4_is_valid_delegation(delegation, flags);
1176         if (ret) {
1177                 nfs4_stateid_copy(dst, &delegation->stateid);
1178                 nfs_mark_delegation_referenced(delegation);
1179                 if (cred)
1180                         *cred = get_rpccred(delegation->cred);
1181         }
1182         rcu_read_unlock();
1183         return ret;
1184 }
1185
1186 /**
1187  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1188  * @inode: inode to check
1189  *
1190  * This function checks the number of outstanding writes to the file
1191  * against the delegation 'space_limit' field to see if
1192  * the spec requires us to flush the file on close.
1193  */
1194 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1195 {
1196         struct nfs_inode *nfsi = NFS_I(inode);
1197         struct nfs_delegation *delegation;
1198         bool ret = true;
1199
1200         rcu_read_lock();
1201         delegation = rcu_dereference(nfsi->delegation);
1202         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1203                 goto out;
1204         if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1205                 ret = false;
1206 out:
1207         rcu_read_unlock();
1208         return ret;
1209 }