fs/nfs/delegation.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/fs/nfs/delegation.c
   4  *
   5  * Copyright (C) 2004 Trond Myklebust
   6  *
   7  * NFS file delegation management
   8  *
   9  */
  10 #include <linux/completion.h>
  11 #include <linux/kthread.h>
  12 #include <linux/module.h>
  13 #include <linux/sched.h>
  14 #include <linux/slab.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/iversion.h>
  17
  18 #include <linux/nfs4.h>
  19 #include <linux/nfs_fs.h>
  20 #include <linux/nfs_xdr.h>
  21
  22 #include "nfs4_fs.h"
  23 #include "nfs4session.h"
  24 #include "delegation.h"
  25 #include "internal.h"
  26 #include "nfs4trace.h"
  27
  28 static void nfs_free_delegation(struct nfs_delegation *delegation)
  29 {
  30         put_cred(delegation->cred);
  31         delegation->cred = NULL;
  32         kfree_rcu(delegation, rcu);
  33 }
  34
  35 /**
  36  * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
  37  * @delegation: delegation to process
  38  *
  39  */
  40 void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
  41 {
  42         set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
  43 }
  44
  45 static bool
  46 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
  47                 fmode_t flags)
  48 {
  49         if (delegation != NULL && (delegation->type & flags) == flags &&
  50             !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
  51             !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
  52                 return true;
  53         return false;
  54 }
  55
  56 static int
  57 nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
  58 {
  59         struct nfs_delegation *delegation;
  60         int ret = 0;
  61
  62         flags &= FMODE_READ|FMODE_WRITE;
  63         rcu_read_lock();
  64         delegation = rcu_dereference(NFS_I(inode)->delegation);
  65         if (nfs4_is_valid_delegation(delegation, flags)) {
  66                 if (mark)
  67                         nfs_mark_delegation_referenced(delegation);
  68                 ret = 1;
  69         }
  70         rcu_read_unlock();
  71         return ret;
  72 }
  73 /**
  74  * nfs_have_delegation - check if inode has a delegation, mark it
  75  * NFS_DELEGATION_REFERENCED if there is one.
  76  * @inode: inode to check
  77  * @flags: delegation types to check for
  78  *
  79  * Returns one if inode has the indicated delegation, otherwise zero.
  80  */
  81 int nfs4_have_delegation(struct inode *inode, fmode_t flags)
  82 {
  83         return nfs4_do_check_delegation(inode, flags, true);
  84 }
  85
  86 /*
  87  * nfs4_check_delegation - check if inode has a delegation, do not mark
  88  * NFS_DELEGATION_REFERENCED if it has one.
  89  */
  90 int nfs4_check_delegation(struct inode *inode, fmode_t flags)
  91 {
  92         return nfs4_do_check_delegation(inode, flags, false);
  93 }
  94
  95 static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid)
  96 {
  97         struct inode *inode = state->inode;
  98         struct file_lock *fl;
  99         struct file_lock_context *flctx = inode->i_flctx;
 100         struct list_head *list;
 101         int status = 0;
 102
 103         if (flctx == NULL)
 104                 goto out;
 105
 106         list = &flctx->flc_posix;
 107         spin_lock(&flctx->flc_lock);
 108 restart:
 109         list_for_each_entry(fl, list, fl_list) {
 110                 if (nfs_file_open_context(fl->fl_file)->state != state)
 111                         continue;
 112                 spin_unlock(&flctx->flc_lock);
 113                 status = nfs4_lock_delegation_recall(fl, state, stateid);
 114                 if (status < 0)
 115                         goto out;
 116                 spin_lock(&flctx->flc_lock);
 117         }
 118         if (list == &flctx->flc_posix) {
 119                 list = &flctx->flc_flock;
 120                 goto restart;
 121         }
 122         spin_unlock(&flctx->flc_lock);
 123 out:
 124         return status;
 125 }
 126
 127 static int nfs_delegation_claim_opens(struct inode *inode,
 128                 const nfs4_stateid *stateid, fmode_t type)
 129 {
 130         struct nfs_inode *nfsi = NFS_I(inode);
 131         struct nfs_open_context *ctx;
 132         struct nfs4_state_owner *sp;
 133         struct nfs4_state *state;
 134         unsigned int seq;
 135         int err;
 136
 137 again:
 138         rcu_read_lock();
 139         list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
 140                 state = ctx->state;
 141                 if (state == NULL)
 142                         continue;
 143                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 144                         continue;
 145                 if (!nfs4_valid_open_stateid(state))
 146                         continue;
 147                 if (!nfs4_stateid_match(&state->stateid, stateid))
 148                         continue;
 149                 if (!get_nfs_open_context(ctx))
 150                         continue;
 151                 rcu_read_unlock();
 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);
 157                 if (!err)
 158                         err = nfs_delegation_claim_locks(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         rcu_read_unlock();
 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, const struct cred *cred,
 181                                   fmode_t type,
 182                                   const nfs4_stateid *stateid,
 183                                   unsigned long pagemod_limit)
 184 {
 185         struct nfs_delegation *delegation;
 186         const struct 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_cred(cred);
 198                         clear_bit(NFS_DELEGATION_NEED_RECLAIM,
 199                                   &delegation->flags);
 200                         spin_unlock(&delegation->lock);
 201                         rcu_read_unlock();
 202                         put_cred(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         if (!inode)
 234                 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);
 235         spin_unlock(&delegation->lock);
 236         return inode;
 237 }
 238
 239 static struct nfs_delegation *
 240 nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 241 {
 242         struct nfs_delegation *ret = NULL;
 243         struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
 244
 245         if (delegation == NULL)
 246                 goto out;
 247         spin_lock(&delegation->lock);
 248         if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 249                 ret = delegation;
 250         spin_unlock(&delegation->lock);
 251 out:
 252         return ret;
 253 }
 254
 255 static struct nfs_delegation *
 256 nfs_start_delegation_return(struct nfs_inode *nfsi)
 257 {
 258         struct nfs_delegation *delegation;
 259
 260         rcu_read_lock();
 261         delegation = nfs_start_delegation_return_locked(nfsi);
 262         rcu_read_unlock();
 263         return delegation;
 264 }
 265
 266 static void
 267 nfs_abort_delegation_return(struct nfs_delegation *delegation,
 268                 struct nfs_client *clp)
 269 {
 270
 271         spin_lock(&delegation->lock);
 272         clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 273         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 274         spin_unlock(&delegation->lock);
 275         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 276 }
 277
 278 static struct nfs_delegation *
 279 nfs_detach_delegation_locked(struct nfs_inode *nfsi,
 280                 struct nfs_delegation *delegation,
 281                 struct nfs_client *clp)
 282 {
 283         struct nfs_delegation *deleg_cur =
 284                 rcu_dereference_protected(nfsi->delegation,
 285                                 lockdep_is_held(&clp->cl_lock));
 286
 287         if (deleg_cur == NULL || delegation != deleg_cur)
 288                 return NULL;
 289
 290         spin_lock(&delegation->lock);
 291         set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
 292         list_del_rcu(&delegation->super_list);
 293         delegation->inode = NULL;
 294         rcu_assign_pointer(nfsi->delegation, NULL);
 295         spin_unlock(&delegation->lock);
 296         return delegation;
 297 }
 298
 299 static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
 300                 struct nfs_delegation *delegation,
 301                 struct nfs_server *server)
 302 {
 303         struct nfs_client *clp = server->nfs_client;
 304
 305         spin_lock(&clp->cl_lock);
 306         delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
 307         spin_unlock(&clp->cl_lock);
 308         return delegation;
 309 }
 310
 311 static struct nfs_delegation *
 312 nfs_inode_detach_delegation(struct inode *inode)
 313 {
 314         struct nfs_inode *nfsi = NFS_I(inode);
 315         struct nfs_server *server = NFS_SERVER(inode);
 316         struct nfs_delegation *delegation;
 317
 318         delegation = nfs_start_delegation_return(nfsi);
 319         if (delegation == NULL)
 320                 return NULL;
 321         return nfs_detach_delegation(nfsi, delegation, server);
 322 }
 323
 324 static void
 325 nfs_update_inplace_delegation(struct nfs_delegation *delegation,
 326                 const struct nfs_delegation *update)
 327 {
 328         if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
 329                 delegation->stateid.seqid = update->stateid.seqid;
 330                 smp_wmb();
 331                 delegation->type = update->type;
 332         }
 333 }
 334
 335 /**
 336  * nfs_inode_set_delegation - set up a delegation on an inode
 337  * @inode: inode to which delegation applies
 338  * @cred: cred to use for subsequent delegation processing
 339  * @type: delegation type
 340  * @stateid: delegation stateid
 341  * @pagemod_limit: write delegation "space_limit"
 342  *
 343  * Returns zero on success, or a negative errno value.
 344  */
 345 int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
 346                                   fmode_t type,
 347                                   const nfs4_stateid *stateid,
 348                                   unsigned long pagemod_limit)
 349 {
 350         struct nfs_server *server = NFS_SERVER(inode);
 351         struct nfs_client *clp = server->nfs_client;
 352         struct nfs_inode *nfsi = NFS_I(inode);
 353         struct nfs_delegation *delegation, *old_delegation;
 354         struct nfs_delegation *freeme = NULL;
 355         int status = 0;
 356
 357         delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
 358         if (delegation == NULL)
 359                 return -ENOMEM;
 360         nfs4_stateid_copy(&delegation->stateid, stateid);
 361         delegation->type = type;
 362         delegation->pagemod_limit = pagemod_limit;
 363         delegation->change_attr = inode_peek_iversion_raw(inode);
 364         delegation->cred = get_cred(cred);
 365         delegation->inode = inode;
 366         delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
 367         spin_lock_init(&delegation->lock);
 368
 369         spin_lock(&clp->cl_lock);
 370         old_delegation = rcu_dereference_protected(nfsi->delegation,
 371                                         lockdep_is_held(&clp->cl_lock));
 372         if (old_delegation != NULL) {
 373                 /* Is this an update of the existing delegation? */
 374                 if (nfs4_stateid_match_other(&old_delegation->stateid,
 375                                         &delegation->stateid)) {
 376                         nfs_update_inplace_delegation(old_delegation,
 377                                         delegation);
 378                         goto out;
 379                 }
 380                 /*
 381                  * Deal with broken servers that hand out two
 382                  * delegations for the same file.
 383                  * Allow for upgrades to a WRITE delegation, but
 384                  * nothing else.
 385                  */
 386                 dfprintk(FILE, "%s: server %s handed out "
 387                                 "a duplicate delegation!\n",
 388                                 __func__, clp->cl_hostname);
 389                 if (delegation->type == old_delegation->type ||
 390                     !(delegation->type & FMODE_WRITE)) {
 391                         freeme = delegation;
 392                         delegation = NULL;
 393                         goto out;
 394                 }
 395                 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
 396                                         &old_delegation->flags))
 397                         goto out;
 398                 freeme = nfs_detach_delegation_locked(nfsi,
 399                                 old_delegation, clp);
 400                 if (freeme == NULL)
 401                         goto out;
 402         }
 403         list_add_tail_rcu(&delegation->super_list, &server->delegations);
 404         rcu_assign_pointer(nfsi->delegation, delegation);
 405         delegation = NULL;
 406
 407         trace_nfs4_set_delegation(inode, type);
 408
 409         spin_lock(&inode->i_lock);
 410         if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME))
 411                 NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED;
 412         spin_unlock(&inode->i_lock);
 413 out:
 414         spin_unlock(&clp->cl_lock);
 415         if (delegation != NULL)
 416                 nfs_free_delegation(delegation);
 417         if (freeme != NULL)
 418                 nfs_do_return_delegation(inode, freeme, 0);
 419         return status;
 420 }
 421
 422 /*
 423  * Basic procedure for returning a delegation to the server
 424  */
 425 static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
 426 {
 427         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 428         struct nfs_inode *nfsi = NFS_I(inode);
 429         int err = 0;
 430
 431         if (delegation == NULL)
 432                 return 0;
 433         do {
 434                 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 435                         break;
 436                 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
 437                                 delegation->type);
 438                 if (!issync || err != -EAGAIN)
 439                         break;
 440                 /*
 441                  * Guard against state recovery
 442                  */
 443                 err = nfs4_wait_clnt_recover(clp);
 444         } while (err == 0);
 445
 446         if (err) {
 447                 nfs_abort_delegation_return(delegation, clp);
 448                 goto out;
 449         }
 450         if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
 451                 goto out;
 452
 453         err = nfs_do_return_delegation(inode, delegation, issync);
 454 out:
 455         return err;
 456 }
 457
 458 static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 459 {
 460         bool ret = false;
 461
 462         if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
 463                 goto out;
 464         if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
 465                 ret = true;
 466         if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
 467                 struct inode *inode;
 468
 469                 spin_lock(&delegation->lock);
 470                 inode = delegation->inode;
 471                 if (inode && list_empty(&NFS_I(inode)->open_files))
 472                         ret = true;
 473                 spin_unlock(&delegation->lock);
 474         }
 475 out:
 476         return ret;
 477 }
 478
 479 /**
 480  * nfs_client_return_marked_delegations - return previously marked delegations
 481  * @clp: nfs_client to process
 482  *
 483  * Note that this function is designed to be called by the state
 484  * manager thread. For this reason, it cannot flush the dirty data,
 485  * since that could deadlock in case of a state recovery error.
 486  *
 487  * Returns zero on success, or a negative errno value.
 488  */
 489 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 490 {
 491         struct nfs_delegation *delegation;
 492         struct nfs_delegation *prev;
 493         struct nfs_server *server;
 494         struct inode *inode;
 495         struct inode *place_holder = NULL;
 496         struct nfs_delegation *place_holder_deleg = NULL;
 497         int err = 0;
 498
 499 restart:
 500         /*
 501          * To avoid quadratic looping we hold a reference
 502          * to an inode place_holder.  Each time we restart, we
 503          * list nfs_servers from the server of that inode, and
 504          * delegation in the server from the delegations of that
 505          * inode.
 506          * prev is an RCU-protected pointer to a delegation which
 507          * wasn't marked for return and might be a good choice for
 508          * the next place_holder.
 509          */
 510         rcu_read_lock();
 511         prev = NULL;
 512         if (place_holder)
 513                 server = NFS_SERVER(place_holder);
 514         else
 515                 server = list_entry_rcu(clp->cl_superblocks.next,
 516                                         struct nfs_server, client_link);
 517         list_for_each_entry_from_rcu(server, &clp->cl_superblocks, client_link) {
 518                 delegation = NULL;
 519                 if (place_holder && server == NFS_SERVER(place_holder))
 520                         delegation = rcu_dereference(NFS_I(place_holder)->delegation);
 521                 if (!delegation || delegation != place_holder_deleg)
 522                         delegation = list_entry_rcu(server->delegations.next,
 523                                                     struct nfs_delegation, super_list);
 524                 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
 525                         struct inode *to_put = NULL;
 526
 527                         if (!nfs_delegation_need_return(delegation)) {
 528                                 prev = delegation;
 529                                 continue;
 530                         }
 531                         if (!nfs_sb_active(server->super))
 532                                 break; /* continue in outer loop */
 533
 534                         if (prev) {
 535                                 struct inode *tmp;
 536
 537                                 tmp = nfs_delegation_grab_inode(prev);
 538                                 if (tmp) {
 539                                         to_put = place_holder;
 540                                         place_holder = tmp;
 541                                         place_holder_deleg = prev;
 542                                 }
 543                         }
 544
 545                         inode = nfs_delegation_grab_inode(delegation);
 546                         if (inode == NULL) {
 547                                 rcu_read_unlock();
 548                                 if (to_put)
 549                                         iput(to_put);
 550                                 nfs_sb_deactive(server->super);
 551                                 goto restart;
 552                         }
 553                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 554                         rcu_read_unlock();
 555
 556                         if (to_put)
 557                                 iput(to_put);
 558
 559                         err = nfs_end_delegation_return(inode, delegation, 0);
 560                         iput(inode);
 561                         nfs_sb_deactive(server->super);
 562                         cond_resched();
 563                         if (!err)
 564                                 goto restart;
 565                         set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 566                         if (place_holder)
 567                                 iput(place_holder);
 568                         return err;
 569                 }
 570         }
 571         rcu_read_unlock();
 572         if (place_holder)
 573                 iput(place_holder);
 574         return 0;
 575 }
 576
 577 /**
 578  * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
 579  * @inode: inode to process
 580  *
 581  * Does not protect against delegation reclaims, therefore really only safe
 582  * to be called from nfs4_clear_inode().
 583  */
 584 void nfs_inode_return_delegation_noreclaim(struct inode *inode)
 585 {
 586         struct nfs_delegation *delegation;
 587
 588         delegation = nfs_inode_detach_delegation(inode);
 589         if (delegation != NULL)
 590                 nfs_do_return_delegation(inode, delegation, 1);
 591 }
 592
 593 /**
 594  * nfs_inode_return_delegation - synchronously return a delegation
 595  * @inode: inode to process
 596  *
 597  * This routine will always flush any dirty data to disk on the
 598  * assumption that if we need to return the delegation, then
 599  * we should stop caching.
 600  *
 601  * Returns zero on success, or a negative errno value.
 602  */
 603 int nfs4_inode_return_delegation(struct inode *inode)
 604 {
 605         struct nfs_inode *nfsi = NFS_I(inode);
 606         struct nfs_delegation *delegation;
 607         int err = 0;
 608
 609         nfs_wb_all(inode);
 610         delegation = nfs_start_delegation_return(nfsi);
 611         if (delegation != NULL)
 612                 err = nfs_end_delegation_return(inode, delegation, 1);
 613         return err;
 614 }
 615
 616 /**
 617  * nfs4_inode_make_writeable
 618  * @inode: pointer to inode
 619  *
 620  * Make the inode writeable by returning the delegation if necessary
 621  *
 622  * Returns zero on success, or a negative errno value.
 623  */
 624 int nfs4_inode_make_writeable(struct inode *inode)
 625 {
 626         if (!nfs4_has_session(NFS_SERVER(inode)->nfs_client) ||
 627             !nfs4_check_delegation(inode, FMODE_WRITE))
 628                 return nfs4_inode_return_delegation(inode);
 629         return 0;
 630 }
 631
 632 static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 633                 struct nfs_delegation *delegation)
 634 {
 635         set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 636         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 637 }
 638
 639 static void nfs_mark_return_delegation(struct nfs_server *server,
 640                 struct nfs_delegation *delegation)
 641 {
 642         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
 643         set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 644 }
 645
 646 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 647 {
 648         struct nfs_delegation *delegation;
 649         bool ret = false;
 650
 651         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 652                 nfs_mark_return_delegation(server, delegation);
 653                 ret = true;
 654         }
 655         return ret;
 656 }
 657
 658 static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
 659 {
 660         struct nfs_server *server;
 661
 662         rcu_read_lock();
 663         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 664                 nfs_server_mark_return_all_delegations(server);
 665         rcu_read_unlock();
 666 }
 667
 668 static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 669 {
 670         if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
 671                 nfs4_schedule_state_manager(clp);
 672 }
 673
 674 /**
 675  * nfs_expire_all_delegations
 676  * @clp: client to process
 677  *
 678  */
 679 void nfs_expire_all_delegations(struct nfs_client *clp)
 680 {
 681         nfs_client_mark_return_all_delegations(clp);
 682         nfs_delegation_run_state_manager(clp);
 683 }
 684
 685 /**
 686  * nfs_super_return_all_delegations - return delegations for one superblock
 687  * @server: pointer to nfs_server to process
 688  *
 689  */
 690 void nfs_server_return_all_delegations(struct nfs_server *server)
 691 {
 692         struct nfs_client *clp = server->nfs_client;
 693         bool need_wait;
 694
 695         if (clp == NULL)
 696                 return;
 697
 698         rcu_read_lock();
 699         need_wait = nfs_server_mark_return_all_delegations(server);
 700         rcu_read_unlock();
 701
 702         if (need_wait) {
 703                 nfs4_schedule_state_manager(clp);
 704                 nfs4_wait_clnt_recover(clp);
 705         }
 706 }
 707
 708 static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
 709                                                  fmode_t flags)
 710 {
 711         struct nfs_delegation *delegation;
 712
 713         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 714                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
 715                         continue;
 716                 if (delegation->type & flags)
 717                         nfs_mark_return_if_closed_delegation(server, delegation);
 718         }
 719 }
 720
 721 static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
 722                                                         fmode_t flags)
 723 {
 724         struct nfs_server *server;
 725
 726         rcu_read_lock();
 727         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 728                 nfs_mark_return_unused_delegation_types(server, flags);
 729         rcu_read_unlock();
 730 }
 731
 732 static void nfs_mark_delegation_revoked(struct nfs_server *server,
 733                 struct nfs_delegation *delegation)
 734 {
 735         set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
 736         delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
 737         nfs_mark_return_delegation(server, delegation);
 738 }
 739
 740 static bool nfs_revoke_delegation(struct inode *inode,
 741                 const nfs4_stateid *stateid)
 742 {
 743         struct nfs_delegation *delegation;
 744         nfs4_stateid tmp;
 745         bool ret = false;
 746
 747         rcu_read_lock();
 748         delegation = rcu_dereference(NFS_I(inode)->delegation);
 749         if (delegation == NULL)
 750                 goto out;
 751         if (stateid == NULL) {
 752                 nfs4_stateid_copy(&tmp, &delegation->stateid);
 753                 stateid = &tmp;
 754         } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
 755                 goto out;
 756         nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
 757         ret = true;
 758 out:
 759         rcu_read_unlock();
 760         if (ret)
 761                 nfs_inode_find_state_and_recover(inode, stateid);
 762         return ret;
 763 }
 764
 765 void nfs_remove_bad_delegation(struct inode *inode,
 766                 const nfs4_stateid *stateid)
 767 {
 768         struct nfs_delegation *delegation;
 769
 770         if (!nfs_revoke_delegation(inode, stateid))
 771                 return;
 772         delegation = nfs_inode_detach_delegation(inode);
 773         if (delegation)
 774                 nfs_free_delegation(delegation);
 775 }
 776 EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
 777
 778 /**
 779  * nfs_expire_unused_delegation_types
 780  * @clp: client to process
 781  * @flags: delegation types to expire
 782  *
 783  */
 784 void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
 785 {
 786         nfs_client_mark_return_unused_delegation_types(clp, flags);
 787         nfs_delegation_run_state_manager(clp);
 788 }
 789
 790 static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
 791 {
 792         struct nfs_delegation *delegation;
 793
 794         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 795                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
 796                         continue;
 797                 nfs_mark_return_if_closed_delegation(server, delegation);
 798         }
 799 }
 800
 801 /**
 802  * nfs_expire_unreferenced_delegations - Eliminate unused delegations
 803  * @clp: nfs_client to process
 804  *
 805  */
 806 void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 807 {
 808         struct nfs_server *server;
 809
 810         rcu_read_lock();
 811         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 812                 nfs_mark_return_unreferenced_delegations(server);
 813         rcu_read_unlock();
 814
 815         nfs_delegation_run_state_manager(clp);
 816 }
 817
 818 /**
 819  * nfs_async_inode_return_delegation - asynchronously return a delegation
 820  * @inode: inode to process
 821  * @stateid: state ID information
 822  *
 823  * Returns zero on success, or a negative errno value.
 824  */
 825 int nfs_async_inode_return_delegation(struct inode *inode,
 826                                       const nfs4_stateid *stateid)
 827 {
 828         struct nfs_server *server = NFS_SERVER(inode);
 829         struct nfs_client *clp = server->nfs_client;
 830         struct nfs_delegation *delegation;
 831
 832         rcu_read_lock();
 833         delegation = rcu_dereference(NFS_I(inode)->delegation);
 834         if (delegation == NULL)
 835                 goto out_enoent;
 836         if (stateid != NULL &&
 837             !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
 838                 goto out_enoent;
 839         nfs_mark_return_delegation(server, delegation);
 840         rcu_read_unlock();
 841
 842         nfs_delegation_run_state_manager(clp);
 843         return 0;
 844 out_enoent:
 845         rcu_read_unlock();
 846         return -ENOENT;
 847 }
 848
 849 static struct inode *
 850 nfs_delegation_find_inode_server(struct nfs_server *server,
 851                                  const struct nfs_fh *fhandle)
 852 {
 853         struct nfs_delegation *delegation;
 854         struct inode *freeme, *res = NULL;
 855
 856         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 857                 spin_lock(&delegation->lock);
 858                 if (delegation->inode != NULL &&
 859                     nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 860                         freeme = igrab(delegation->inode);
 861                         if (freeme && nfs_sb_active(freeme->i_sb))
 862                                 res = freeme;
 863                         spin_unlock(&delegation->lock);
 864                         if (res != NULL)
 865                                 return res;
 866                         if (freeme) {
 867                                 rcu_read_unlock();
 868                                 iput(freeme);
 869                                 rcu_read_lock();
 870                         }
 871                         return ERR_PTR(-EAGAIN);
 872                 }
 873                 spin_unlock(&delegation->lock);
 874         }
 875         return ERR_PTR(-ENOENT);
 876 }
 877
 878 /**
 879  * nfs_delegation_find_inode - retrieve the inode associated with a delegation
 880  * @clp: client state handle
 881  * @fhandle: filehandle from a delegation recall
 882  *
 883  * Returns pointer to inode matching "fhandle," or NULL if a matching inode
 884  * cannot be found.
 885  */
 886 struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 887                                         const struct nfs_fh *fhandle)
 888 {
 889         struct nfs_server *server;
 890         struct inode *res;
 891
 892         rcu_read_lock();
 893         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 894                 res = nfs_delegation_find_inode_server(server, fhandle);
 895                 if (res != ERR_PTR(-ENOENT)) {
 896                         rcu_read_unlock();
 897                         return res;
 898                 }
 899         }
 900         rcu_read_unlock();
 901         return ERR_PTR(-ENOENT);
 902 }
 903
 904 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 905 {
 906         struct nfs_delegation *delegation;
 907
 908         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 909                 /*
 910                  * If the delegation may have been admin revoked, then we
 911                  * cannot reclaim it.
 912                  */
 913                 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
 914                         continue;
 915                 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 916         }
 917 }
 918
 919 /**
 920  * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
 921  * @clp: nfs_client to process
 922  *
 923  */
 924 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 925 {
 926         struct nfs_server *server;
 927
 928         rcu_read_lock();
 929         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 930                 nfs_delegation_mark_reclaim_server(server);
 931         rcu_read_unlock();
 932 }
 933
 934 /**
 935  * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
 936  * @clp: nfs_client to process
 937  *
 938  */
 939 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 940 {
 941         struct nfs_delegation *delegation;
 942         struct nfs_server *server;
 943         struct inode *inode;
 944
 945 restart:
 946         rcu_read_lock();
 947         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 948                 list_for_each_entry_rcu(delegation, &server->delegations,
 949                                                                 super_list) {
 950                         if (test_bit(NFS_DELEGATION_INODE_FREEING,
 951                                                 &delegation->flags) ||
 952                             test_bit(NFS_DELEGATION_RETURNING,
 953                                                 &delegation->flags) ||
 954                             test_bit(NFS_DELEGATION_NEED_RECLAIM,
 955                                                 &delegation->flags) == 0)
 956                                 continue;
 957                         if (!nfs_sb_active(server->super))
 958                                 break; /* continue in outer loop */
 959                         inode = nfs_delegation_grab_inode(delegation);
 960                         if (inode == NULL) {
 961                                 rcu_read_unlock();
 962                                 nfs_sb_deactive(server->super);
 963                                 goto restart;
 964                         }
 965                         delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 966                         rcu_read_unlock();
 967                         if (delegation != NULL) {
 968                                 delegation = nfs_detach_delegation(NFS_I(inode),
 969                                         delegation, server);
 970                                 if (delegation != NULL)
 971                                         nfs_free_delegation(delegation);
 972                         }
 973                         iput(inode);
 974                         nfs_sb_deactive(server->super);
 975                         cond_resched();
 976                         goto restart;
 977                 }
 978         }
 979         rcu_read_unlock();
 980 }
 981
 982 static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
 983 {
 984         return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
 985                                 BIT(NFS4CLNT_LEASE_EXPIRED) |
 986                                 BIT(NFS4CLNT_SESSION_RESET))) != 0;
 987 }
 988
 989 static void nfs_mark_test_expired_delegation(struct nfs_server *server,
 990             struct nfs_delegation *delegation)
 991 {
 992         if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
 993                 return;
 994         clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
 995         set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
 996         set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
 997 }
 998
 999 static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
1000                 struct inode *inode)
1001 {
1002         struct nfs_delegation *delegation;
1003
1004         rcu_read_lock();
1005         delegation = rcu_dereference(NFS_I(inode)->delegation);
1006         if (delegation)
1007                 nfs_mark_test_expired_delegation(server, delegation);
1008         rcu_read_unlock();
1009
1010 }
1011
1012 static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
1013 {
1014         struct nfs_delegation *delegation;
1015
1016         list_for_each_entry_rcu(delegation, &server->delegations, super_list)
1017                 nfs_mark_test_expired_delegation(server, delegation);
1018 }
1019
1020 /**
1021  * nfs_mark_test_expired_all_delegations - mark all delegations for testing
1022  * @clp: nfs_client to process
1023  *
1024  * Iterates through all the delegations associated with this server and
1025  * marks them as needing to be checked for validity.
1026  */
1027 void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
1028 {
1029         struct nfs_server *server;
1030
1031         rcu_read_lock();
1032         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1033                 nfs_delegation_mark_test_expired_server(server);
1034         rcu_read_unlock();
1035 }
1036
1037 /**
1038  * nfs_test_expired_all_delegations - test all delegations for a client
1039  * @clp: nfs_client to process
1040  *
1041  * Helper for handling "recallable state revoked" status from server.
1042  */
1043 void nfs_test_expired_all_delegations(struct nfs_client *clp)
1044 {
1045         nfs_mark_test_expired_all_delegations(clp);
1046         nfs4_schedule_state_manager(clp);
1047 }
1048
1049 static void
1050 nfs_delegation_test_free_expired(struct inode *inode,
1051                 nfs4_stateid *stateid,
1052                 const struct cred *cred)
1053 {
1054         struct nfs_server *server = NFS_SERVER(inode);
1055         const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;
1056         int status;
1057
1058         if (!cred)
1059                 return;
1060         status = ops->test_and_free_expired(server, stateid, cred);
1061         if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
1062                 nfs_remove_bad_delegation(inode, stateid);
1063 }
1064
1065 /**
1066  * nfs_reap_expired_delegations - reap expired delegations
1067  * @clp: nfs_client to process
1068  *
1069  * Iterates through all the delegations associated with this server and
1070  * checks if they have may have been revoked. This function is usually
1071  * expected to be called in cases where the server may have lost its
1072  * lease.
1073  */
1074 void nfs_reap_expired_delegations(struct nfs_client *clp)
1075 {
1076         struct nfs_delegation *delegation;
1077         struct nfs_server *server;
1078         struct inode *inode;
1079         const struct cred *cred;
1080         nfs4_stateid stateid;
1081
1082 restart:
1083         rcu_read_lock();
1084         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
1085                 list_for_each_entry_rcu(delegation, &server->delegations,
1086                                                                 super_list) {
1087                         if (test_bit(NFS_DELEGATION_INODE_FREEING,
1088                                                 &delegation->flags) ||
1089                             test_bit(NFS_DELEGATION_RETURNING,
1090                                                 &delegation->flags) ||
1091                             test_bit(NFS_DELEGATION_TEST_EXPIRED,
1092                                                 &delegation->flags) == 0)
1093                                 continue;
1094                         if (!nfs_sb_active(server->super))
1095                                 break; /* continue in outer loop */
1096                         inode = nfs_delegation_grab_inode(delegation);
1097                         if (inode == NULL) {
1098                                 rcu_read_unlock();
1099                                 nfs_sb_deactive(server->super);
1100                                 goto restart;
1101                         }
1102                         cred = get_cred_rcu(delegation->cred);
1103                         nfs4_stateid_copy(&stateid, &delegation->stateid);
1104                         clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1105                         rcu_read_unlock();
1106                         nfs_delegation_test_free_expired(inode, &stateid, cred);
1107                         put_cred(cred);
1108                         if (nfs4_server_rebooted(clp)) {
1109                                 nfs_inode_mark_test_expired_delegation(server,inode);
1110                                 iput(inode);
1111                                 nfs_sb_deactive(server->super);
1112                                 return;
1113                         }
1114                         iput(inode);
1115                         nfs_sb_deactive(server->super);
1116                         cond_resched();
1117                         goto restart;
1118                 }
1119         }
1120         rcu_read_unlock();
1121 }
1122
1123 void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1124                 const nfs4_stateid *stateid)
1125 {
1126         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1127         struct nfs_delegation *delegation;
1128         bool found = false;
1129
1130         rcu_read_lock();
1131         delegation = rcu_dereference(NFS_I(inode)->delegation);
1132         if (delegation &&
1133             nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1134                 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1135                 found = true;
1136         }
1137         rcu_read_unlock();
1138         if (found)
1139                 nfs4_schedule_state_manager(clp);
1140 }
1141
1142 /**
1143  * nfs_delegations_present - check for existence of delegations
1144  * @clp: client state handle
1145  *
1146  * Returns one if there are any nfs_delegation structures attached
1147  * to this nfs_client.
1148  */
1149 int nfs_delegations_present(struct nfs_client *clp)
1150 {
1151         struct nfs_server *server;
1152         int ret = 0;
1153
1154         rcu_read_lock();
1155         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1156                 if (!list_empty(&server->delegations)) {
1157                         ret = 1;
1158                         break;
1159                 }
1160         rcu_read_unlock();
1161         return ret;
1162 }
1163
1164 /**
1165  * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1166  * @dst: stateid to refresh
1167  * @inode: inode to check
1168  *
1169  * Returns "true" and updates "dst->seqid" * if inode had a delegation
1170  * that matches our delegation stateid. Otherwise "false" is returned.
1171  */
1172 bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1173 {
1174         struct nfs_delegation *delegation;
1175         bool ret = false;
1176         if (!inode)
1177                 goto out;
1178
1179         rcu_read_lock();
1180         delegation = rcu_dereference(NFS_I(inode)->delegation);
1181         if (delegation != NULL &&
1182             nfs4_stateid_match_other(dst, &delegation->stateid)) {
1183                 dst->seqid = delegation->stateid.seqid;
1184                 return ret;
1185         }
1186         rcu_read_unlock();
1187 out:
1188         return ret;
1189 }
1190
1191 /**
1192  * nfs4_copy_delegation_stateid - Copy inode's state ID information
1193  * @inode: inode to check
1194  * @flags: delegation type requirement
1195  * @dst: stateid data structure to fill in
1196  * @cred: optional argument to retrieve credential
1197  *
1198  * Returns "true" and fills in "dst->data" * if inode had a delegation,
1199  * otherwise "false" is returned.
1200  */
1201 bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1202                 nfs4_stateid *dst, const struct cred **cred)
1203 {
1204         struct nfs_inode *nfsi = NFS_I(inode);
1205         struct nfs_delegation *delegation;
1206         bool ret;
1207
1208         flags &= FMODE_READ|FMODE_WRITE;
1209         rcu_read_lock();
1210         delegation = rcu_dereference(nfsi->delegation);
1211         ret = nfs4_is_valid_delegation(delegation, flags);
1212         if (ret) {
1213                 nfs4_stateid_copy(dst, &delegation->stateid);
1214                 nfs_mark_delegation_referenced(delegation);
1215                 if (cred)
1216                         *cred = get_cred(delegation->cred);
1217         }
1218         rcu_read_unlock();
1219         return ret;
1220 }
1221
1222 /**
1223  * nfs4_delegation_flush_on_close - Check if we must flush file on close
1224  * @inode: inode to check
1225  *
1226  * This function checks the number of outstanding writes to the file
1227  * against the delegation 'space_limit' field to see if
1228  * the spec requires us to flush the file on close.
1229  */
1230 bool nfs4_delegation_flush_on_close(const struct inode *inode)
1231 {
1232         struct nfs_inode *nfsi = NFS_I(inode);
1233         struct nfs_delegation *delegation;
1234         bool ret = true;
1235
1236         rcu_read_lock();
1237         delegation = rcu_dereference(nfsi->delegation);
1238         if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1239                 goto out;
1240         if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1241                 ret = false;
1242 out:
1243         rcu_read_unlock();
1244         return ret;
1245 }