1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * linux/fs/nfs/delegation.c 4 * 5 * Copyright (C) 2004 Trond Myklebust 6 * 7 * NFS file delegation management 8 * 9 */ 10#include <linux/completion.h> 11#include <linux/kthread.h> 12#include <linux/module.h> 13#include <linux/sched.h> 14#include <linux/slab.h> 15#include <linux/spinlock.h> 16#include <linux/iversion.h> 17 18#include <linux/nfs4.h> 19#include <linux/nfs_fs.h> 20#include <linux/nfs_xdr.h> 21 22#include "nfs4_fs.h" 23#include "nfs4session.h" 24#include "delegation.h" 25#include "internal.h" 26#include "nfs4trace.h" 27 28#define NFS_DEFAULT_DELEGATION_WATERMARK (5000U) 29 30static atomic_long_t nfs_active_delegations; 31static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK; 32 33static void __nfs_free_delegation(struct nfs_delegation *delegation) 34{ 35 put_cred(delegation->cred); 36 delegation->cred = NULL; 37 kfree_rcu(delegation, rcu); 38} 39 40static void nfs_mark_delegation_revoked(struct nfs_delegation *delegation) 41{ 42 if (!test_and_set_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) { 43 delegation->stateid.type = NFS4_INVALID_STATEID_TYPE; 44 atomic_long_dec(&nfs_active_delegations); 45 if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) 46 nfs_clear_verifier_delegated(delegation->inode); 47 } 48} 49 50static struct nfs_delegation *nfs_get_delegation(struct nfs_delegation *delegation) 51{ 52 refcount_inc(&delegation->refcount); 53 return delegation; 54} 55 56static void nfs_put_delegation(struct nfs_delegation *delegation) 57{ 58 if (refcount_dec_and_test(&delegation->refcount)) 59 __nfs_free_delegation(delegation); 60} 61 62static void nfs_free_delegation(struct nfs_delegation *delegation) 63{ 64 nfs_mark_delegation_revoked(delegation); 65 nfs_put_delegation(delegation); 66} 67 68/** 69 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag 70 * @delegation: delegation to process 71 * 72 */ 73void nfs_mark_delegation_referenced(struct nfs_delegation *delegation) 74{ 75 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags); 76} 77 78static void nfs_mark_return_delegation(struct nfs_server *server, 79 struct nfs_delegation *delegation) 80{ 81 set_bit(NFS_DELEGATION_RETURN, &delegation->flags); 82 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state); 83} 84 85static bool 86nfs4_is_valid_delegation(const struct nfs_delegation *delegation, 87 fmode_t flags) 88{ 89 if (delegation != NULL && (delegation->type & flags) == flags && 90 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) && 91 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) 92 return true; 93 return false; 94} 95 96struct nfs_delegation *nfs4_get_valid_delegation(const struct inode *inode) 97{ 98 struct nfs_delegation *delegation; 99 100 delegation = rcu_dereference(NFS_I(inode)->delegation); 101 if (nfs4_is_valid_delegation(delegation, 0)) 102 return delegation; 103 return NULL; 104} 105 106static int 107nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark) 108{ 109 struct nfs_delegation *delegation; 110 int ret = 0; 111 112 flags &= FMODE_READ|FMODE_WRITE; 113 rcu_read_lock(); 114 delegation = rcu_dereference(NFS_I(inode)->delegation); 115 if (nfs4_is_valid_delegation(delegation, flags)) { 116 if (mark) 117 nfs_mark_delegation_referenced(delegation); 118 ret = 1; 119 } 120 rcu_read_unlock(); 121 return ret; 122} 123/** 124 * nfs_have_delegation - check if inode has a delegation, mark it 125 * NFS_DELEGATION_REFERENCED if there is one. 126 * @inode: inode to check 127 * @flags: delegation types to check for 128 * 129 * Returns one if inode has the indicated delegation, otherwise zero. 130 */ 131int nfs4_have_delegation(struct inode *inode, fmode_t flags) 132{ 133 return nfs4_do_check_delegation(inode, flags, true); 134} 135 136/* 137 * nfs4_check_delegation - check if inode has a delegation, do not mark 138 * NFS_DELEGATION_REFERENCED if it has one. 139 */ 140int nfs4_check_delegation(struct inode *inode, fmode_t flags) 141{ 142 return nfs4_do_check_delegation(inode, flags, false); 143} 144 145static int nfs_delegation_claim_locks(struct nfs4_state *state, const nfs4_stateid *stateid) 146{ 147 struct inode *inode = state->inode; 148 struct file_lock *fl; 149 struct file_lock_context *flctx = inode->i_flctx; 150 struct list_head *list; 151 int status = 0; 152 153 if (flctx == NULL) 154 goto out; 155 156 list = &flctx->flc_posix; 157 spin_lock(&flctx->flc_lock); 158restart: 159 list_for_each_entry(fl, list, fl_list) { 160 if (nfs_file_open_context(fl->fl_file)->state != state) 161 continue; 162 spin_unlock(&flctx->flc_lock); 163 status = nfs4_lock_delegation_recall(fl, state, stateid); 164 if (status < 0) 165 goto out; 166 spin_lock(&flctx->flc_lock); 167 } 168 if (list == &flctx->flc_posix) { 169 list = &flctx->flc_flock; 170 goto restart; 171 } 172 spin_unlock(&flctx->flc_lock); 173out: 174 return status; 175} 176 177static int nfs_delegation_claim_opens(struct inode *inode, 178 const nfs4_stateid *stateid, fmode_t type) 179{ 180 struct nfs_inode *nfsi = NFS_I(inode); 181 struct nfs_open_context *ctx; 182 struct nfs4_state_owner *sp; 183 struct nfs4_state *state; 184 unsigned int seq; 185 int err; 186 187again: 188 rcu_read_lock(); 189 list_for_each_entry_rcu(ctx, &nfsi->open_files, list) { 190 state = ctx->state; 191 if (state == NULL) 192 continue; 193 if (!test_bit(NFS_DELEGATED_STATE, &state->flags)) 194 continue; 195 if (!nfs4_valid_open_stateid(state)) 196 continue; 197 if (!nfs4_stateid_match(&state->stateid, stateid)) 198 continue; 199 if (!get_nfs_open_context(ctx)) 200 continue; 201 rcu_read_unlock(); 202 sp = state->owner; 203 /* Block nfs4_proc_unlck */ 204 mutex_lock(&sp->so_delegreturn_mutex); 205 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount); 206 err = nfs4_open_delegation_recall(ctx, state, stateid); 207 if (!err) 208 err = nfs_delegation_claim_locks(state, stateid); 209 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq)) 210 err = -EAGAIN; 211 mutex_unlock(&sp->so_delegreturn_mutex); 212 put_nfs_open_context(ctx); 213 if (err != 0) 214 return err; 215 goto again; 216 } 217 rcu_read_unlock(); 218 return 0; 219} 220 221/** 222 * nfs_inode_reclaim_delegation - process a delegation reclaim request 223 * @inode: inode to process 224 * @cred: credential to use for request 225 * @type: delegation type 226 * @stateid: delegation stateid 227 * @pagemod_limit: write delegation "space_limit" 228 * 229 */ 230void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred, 231 fmode_t type, const nfs4_stateid *stateid, 232 unsigned long pagemod_limit) 233{ 234 struct nfs_delegation *delegation; 235 const struct cred *oldcred = NULL; 236 237 rcu_read_lock(); 238 delegation = rcu_dereference(NFS_I(inode)->delegation); 239 if (delegation != NULL) { 240 spin_lock(&delegation->lock); 241 nfs4_stateid_copy(&delegation->stateid, stateid); 242 delegation->type = type; 243 delegation->pagemod_limit = pagemod_limit; 244 oldcred = delegation->cred; 245 delegation->cred = get_cred(cred); 246 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags); 247 if (test_and_clear_bit(NFS_DELEGATION_REVOKED, 248 &delegation->flags)) 249 atomic_long_inc(&nfs_active_delegations); 250 spin_unlock(&delegation->lock); 251 rcu_read_unlock(); 252 put_cred(oldcred); 253 trace_nfs4_reclaim_delegation(inode, type); 254 } else { 255 rcu_read_unlock(); 256 nfs_inode_set_delegation(inode, cred, type, stateid, 257 pagemod_limit); 258 } 259} 260 261static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync) 262{ 263 const struct cred *cred; 264 int res = 0; 265 266 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) { 267 spin_lock(&delegation->lock); 268 cred = get_cred(delegation->cred); 269 spin_unlock(&delegation->lock); 270 res = nfs4_proc_delegreturn(inode, cred, 271 &delegation->stateid, 272 issync); 273 put_cred(cred); 274 } 275 return res; 276} 277 278static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation) 279{ 280 struct inode *inode = NULL; 281 282 spin_lock(&delegation->lock); 283 if (delegation->inode != NULL) 284 inode = igrab(delegation->inode); 285 if (!inode) 286 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags); 287 spin_unlock(&delegation->lock); 288 return inode; 289} 290 291static struct nfs_delegation * 292nfs_start_delegation_return_locked(struct nfs_inode *nfsi) 293{ 294 struct nfs_delegation *ret = NULL; 295 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation); 296 297 if (delegation == NULL) 298 goto out; 299 spin_lock(&delegation->lock); 300 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) { 301 clear_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags); 302 /* Refcount matched in nfs_end_delegation_return() */ 303 ret = nfs_get_delegation(delegation); 304 } 305 spin_unlock(&delegation->lock); 306 if (ret) 307 nfs_clear_verifier_delegated(&nfsi->vfs_inode); 308out: 309 return ret; 310} 311 312static struct nfs_delegation * 313nfs_start_delegation_return(struct nfs_inode *nfsi) 314{ 315 struct nfs_delegation *delegation; 316 317 rcu_read_lock(); 318 delegation = nfs_start_delegation_return_locked(nfsi); 319 rcu_read_unlock(); 320 return delegation; 321} 322 323static void nfs_abort_delegation_return(struct nfs_delegation *delegation, 324 struct nfs_client *clp, int err) 325{ 326 327 spin_lock(&delegation->lock); 328 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags); 329 if (err == -EAGAIN) { 330 set_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags); 331 set_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state); 332 } 333 spin_unlock(&delegation->lock); 334} 335 336static struct nfs_delegation * 337nfs_detach_delegation_locked(struct nfs_inode *nfsi, 338 struct nfs_delegation *delegation, 339 struct nfs_client *clp) 340{ 341 struct nfs_delegation *deleg_cur = 342 rcu_dereference_protected(nfsi->delegation, 343 lockdep_is_held(&clp->cl_lock)); 344 345 if (deleg_cur == NULL || delegation != deleg_cur) 346 return NULL; 347 348 spin_lock(&delegation->lock); 349 if (!delegation->inode) { 350 spin_unlock(&delegation->lock); 351 return NULL; 352 } 353 list_del_rcu(&delegation->super_list); 354 delegation->inode = NULL; 355 rcu_assign_pointer(nfsi->delegation, NULL); 356 spin_unlock(&delegation->lock); 357 return delegation; 358} 359 360static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi, 361 struct nfs_delegation *delegation, 362 struct nfs_server *server) 363{ 364 struct nfs_client *clp = server->nfs_client; 365 366 spin_lock(&clp->cl_lock); 367 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp); 368 spin_unlock(&clp->cl_lock); 369 return delegation; 370} 371 372static struct nfs_delegation * 373nfs_inode_detach_delegation(struct inode *inode) 374{ 375 struct nfs_inode *nfsi = NFS_I(inode); 376 struct nfs_server *server = NFS_SERVER(inode); 377 struct nfs_delegation *delegation; 378 379 rcu_read_lock(); 380 delegation = rcu_dereference(nfsi->delegation); 381 if (delegation != NULL) 382 delegation = nfs_detach_delegation(nfsi, delegation, server); 383 rcu_read_unlock(); 384 return delegation; 385} 386 387static void 388nfs_update_delegation_cred(struct nfs_delegation *delegation, 389 const struct cred *cred) 390{ 391 const struct cred *old; 392 393 if (cred_fscmp(delegation->cred, cred) != 0) { 394 old = xchg(&delegation->cred, get_cred(cred)); 395 put_cred(old); 396 } 397} 398 399static void 400nfs_update_inplace_delegation(struct nfs_delegation *delegation, 401 const struct nfs_delegation *update) 402{ 403 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) { 404 delegation->stateid.seqid = update->stateid.seqid; 405 smp_wmb(); 406 delegation->type = update->type; 407 delegation->pagemod_limit = update->pagemod_limit; 408 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) { 409 delegation->change_attr = update->change_attr; 410 nfs_update_delegation_cred(delegation, update->cred); 411 /* smp_mb__before_atomic() is implicit due to xchg() */ 412 clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags); 413 atomic_long_inc(&nfs_active_delegations); 414 } 415 } 416} 417 418/** 419 * nfs_inode_set_delegation - set up a delegation on an inode 420 * @inode: inode to which delegation applies 421 * @cred: cred to use for subsequent delegation processing 422 * @type: delegation type 423 * @stateid: delegation stateid 424 * @pagemod_limit: write delegation "space_limit" 425 * 426 * Returns zero on success, or a negative errno value. 427 */ 428int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred, 429 fmode_t type, 430 const nfs4_stateid *stateid, 431 unsigned long pagemod_limit) 432{ 433 struct nfs_server *server = NFS_SERVER(inode); 434 struct nfs_client *clp = server->nfs_client; 435 struct nfs_inode *nfsi = NFS_I(inode); 436 struct nfs_delegation *delegation, *old_delegation; 437 struct nfs_delegation *freeme = NULL; 438 int status = 0; 439 440 delegation = kmalloc(sizeof(*delegation), GFP_NOFS); 441 if (delegation == NULL) 442 return -ENOMEM; 443 nfs4_stateid_copy(&delegation->stateid, stateid); 444 refcount_set(&delegation->refcount, 1); 445 delegation->type = type; 446 delegation->pagemod_limit = pagemod_limit; 447 delegation->change_attr = inode_peek_iversion_raw(inode); 448 delegation->cred = get_cred(cred); 449 delegation->inode = inode; 450 delegation->flags = 1<<NFS_DELEGATION_REFERENCED; 451 spin_lock_init(&delegation->lock); 452 453 spin_lock(&clp->cl_lock); 454 old_delegation = rcu_dereference_protected(nfsi->delegation, 455 lockdep_is_held(&clp->cl_lock)); 456 if (old_delegation == NULL) 457 goto add_new; 458 /* Is this an update of the existing delegation? */ 459 if (nfs4_stateid_match_other(&old_delegation->stateid, 460 &delegation->stateid)) { 461 spin_lock(&old_delegation->lock); 462 nfs_update_inplace_delegation(old_delegation, 463 delegation); 464 spin_unlock(&old_delegation->lock); 465 goto out; 466 } 467 if (!test_bit(NFS_DELEGATION_REVOKED, &old_delegation->flags)) { 468 /* 469 * Deal with broken servers that hand out two 470 * delegations for the same file. 471 * Allow for upgrades to a WRITE delegation, but 472 * nothing else. 473 */ 474 dfprintk(FILE, "%s: server %s handed out " 475 "a duplicate delegation!\n", 476 __func__, clp->cl_hostname); 477 if (delegation->type == old_delegation->type || 478 !(delegation->type & FMODE_WRITE)) { 479 freeme = delegation; 480 delegation = NULL; 481 goto out; 482 } 483 if (test_and_set_bit(NFS_DELEGATION_RETURNING, 484 &old_delegation->flags)) 485 goto out; 486 } 487 freeme = nfs_detach_delegation_locked(nfsi, old_delegation, clp); 488 if (freeme == NULL) 489 goto out; 490add_new: 491 list_add_tail_rcu(&delegation->super_list, &server->delegations); 492 rcu_assign_pointer(nfsi->delegation, delegation); 493 delegation = NULL; 494 495 atomic_long_inc(&nfs_active_delegations); 496 497 trace_nfs4_set_delegation(inode, type); 498 499 spin_lock(&inode->i_lock); 500 if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME)) 501 NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED; 502 spin_unlock(&inode->i_lock); 503out: 504 spin_unlock(&clp->cl_lock); 505 if (delegation != NULL) 506 __nfs_free_delegation(delegation); 507 if (freeme != NULL) { 508 nfs_do_return_delegation(inode, freeme, 0); 509 nfs_free_delegation(freeme); 510 } 511 return status; 512} 513 514/* 515 * Basic procedure for returning a delegation to the server 516 */ 517static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync) 518{ 519 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client; 520 int err = 0; 521 522 if (delegation == NULL) 523 return 0; 524 do { 525 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) 526 break; 527 err = nfs_delegation_claim_opens(inode, &delegation->stateid, 528 delegation->type); 529 if (!issync || err != -EAGAIN) 530 break; 531 /* 532 * Guard against state recovery 533 */ 534 err = nfs4_wait_clnt_recover(clp); 535 } while (err == 0); 536 537 if (err) { 538 nfs_abort_delegation_return(delegation, clp, err); 539 goto out; 540 } 541 542 err = nfs_do_return_delegation(inode, delegation, issync); 543out: 544 /* Refcount matched in nfs_start_delegation_return_locked() */ 545 nfs_put_delegation(delegation); 546 return err; 547} 548 549static bool nfs_delegation_need_return(struct nfs_delegation *delegation) 550{ 551 bool ret = false; 552 553 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags)) 554 ret = true; 555 else if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags)) { 556 struct inode *inode; 557 558 spin_lock(&delegation->lock); 559 inode = delegation->inode; 560 if (inode && list_empty(&NFS_I(inode)->open_files)) 561 ret = true; 562 spin_unlock(&delegation->lock); 563 } 564 if (ret) 565 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags); 566 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) || 567 test_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags) || 568 test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) 569 ret = false; 570 571 return ret; 572} 573 574static int nfs_server_return_marked_delegations(struct nfs_server *server, 575 void __always_unused *data) 576{ 577 struct nfs_delegation *delegation; 578 struct nfs_delegation *prev; 579 struct inode *inode; 580 struct inode *place_holder = NULL; 581 struct nfs_delegation *place_holder_deleg = NULL; 582 int err = 0; 583 584restart: 585 /* 586 * To avoid quadratic looping we hold a reference 587 * to an inode place_holder. Each time we restart, we 588 * list delegation in the server from the delegations 589 * of that inode. 590 * prev is an RCU-protected pointer to a delegation which 591 * wasn't marked for return and might be a good choice for 592 * the next place_holder. 593 */ 594 prev = NULL; 595 delegation = NULL; 596 rcu_read_lock(); 597 if (place_holder) 598 delegation = rcu_dereference(NFS_I(place_holder)->delegation); 599 if (!delegation || delegation != place_holder_deleg) 600 delegation = list_entry_rcu(server->delegations.next, 601 struct nfs_delegation, super_list); 602 list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) { 603 struct inode *to_put = NULL; 604 605 if (test_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags)) 606 continue; 607 if (!nfs_delegation_need_return(delegation)) { 608 if (nfs4_is_valid_delegation(delegation, 0)) 609 prev = delegation; 610 continue; 611 } 612 613 if (prev) { 614 struct inode *tmp = nfs_delegation_grab_inode(prev); 615 if (tmp) { 616 to_put = place_holder; 617 place_holder = tmp; 618 place_holder_deleg = prev; 619 } 620 } 621 622 inode = nfs_delegation_grab_inode(delegation); 623 if (inode == NULL) { 624 rcu_read_unlock(); 625 iput(to_put); 626 goto restart; 627 } 628 delegation = nfs_start_delegation_return_locked(NFS_I(inode)); 629 rcu_read_unlock(); 630 631 iput(to_put); 632 633 err = nfs_end_delegation_return(inode, delegation, 0); 634 iput(inode); 635 cond_resched(); 636 if (!err) 637 goto restart; 638 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state); 639 goto out; 640 } 641 rcu_read_unlock(); 642out: 643 iput(place_holder); 644 return err; 645} 646 647static bool nfs_server_clear_delayed_delegations(struct nfs_server *server) 648{ 649 struct nfs_delegation *d; 650 bool ret = false; 651 652 list_for_each_entry_rcu (d, &server->delegations, super_list) { 653 if (!test_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags)) 654 continue; 655 nfs_mark_return_delegation(server, d); 656 clear_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags); 657 ret = true; 658 } 659 return ret; 660} 661 662static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp) 663{ 664 struct nfs_server *server; 665 bool ret = false; 666 667 if (!test_and_clear_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state)) 668 goto out; 669 rcu_read_lock(); 670 list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) { 671 if (nfs_server_clear_delayed_delegations(server)) 672 ret = true; 673 } 674 rcu_read_unlock(); 675out: 676 return ret; 677} 678 679/** 680 * nfs_client_return_marked_delegations - return previously marked delegations 681 * @clp: nfs_client to process 682 * 683 * Note that this function is designed to be called by the state 684 * manager thread. For this reason, it cannot flush the dirty data, 685 * since that could deadlock in case of a state recovery error. 686 * 687 * Returns zero on success, or a negative errno value. 688 */ 689int nfs_client_return_marked_delegations(struct nfs_client *clp) 690{ 691 int err = nfs_client_for_each_server( 692 clp, nfs_server_return_marked_delegations, NULL); 693 if (err) 694 return err; 695 /* If a return was delayed, sleep to prevent hard looping */ 696 if (nfs_client_clear_delayed_delegations(clp)) 697 ssleep(1); 698 return 0; 699} 700 701/** 702 * nfs_inode_evict_delegation - return delegation, don't reclaim opens 703 * @inode: inode to process 704 * 705 * Does not protect against delegation reclaims, therefore really only safe 706 * to be called from nfs4_clear_inode(). Guaranteed to always free 707 * the delegation structure. 708 */ 709void nfs_inode_evict_delegation(struct inode *inode) 710{ 711 struct nfs_delegation *delegation; 712 713 delegation = nfs_inode_detach_delegation(inode); 714 if (delegation != NULL) { 715 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags); 716 set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags); 717 nfs_do_return_delegation(inode, delegation, 1); 718 nfs_free_delegation(delegation); 719 } 720} 721 722/** 723 * nfs_inode_return_delegation - synchronously return a delegation 724 * @inode: inode to process 725 * 726 * This routine will always flush any dirty data to disk on the 727 * assumption that if we need to return the delegation, then 728 * we should stop caching. 729 * 730 * Returns zero on success, or a negative errno value. 731 */ 732int nfs4_inode_return_delegation(struct inode *inode) 733{ 734 struct nfs_inode *nfsi = NFS_I(inode); 735 struct nfs_delegation *delegation; 736 int err = 0; 737 738 nfs_wb_all(inode); 739 delegation = nfs_start_delegation_return(nfsi); 740 if (delegation != NULL) 741 err = nfs_end_delegation_return(inode, delegation, 1); 742 return err; 743} 744 745/** 746 * nfs_inode_return_delegation_on_close - asynchronously return a delegation 747 * @inode: inode to process 748 * 749 * This routine is called on file close in order to determine if the 750 * inode delegation needs to be returned immediately. 751 */ 752void nfs4_inode_return_delegation_on_close(struct inode *inode) 753{ 754 struct nfs_delegation *delegation; 755 struct nfs_delegation *ret = NULL; 756 757 if (!inode) 758 return; 759 rcu_read_lock(); 760 delegation = nfs4_get_valid_delegation(inode); 761 if (!delegation) 762 goto out; 763 if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) || 764 atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) { 765 spin_lock(&delegation->lock); 766 if (delegation->inode && 767 list_empty(&NFS_I(inode)->open_files) && 768 !test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) { 769 clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags); 770 /* Refcount matched in nfs_end_delegation_return() */ 771 ret = nfs_get_delegation(delegation); 772 } 773 spin_unlock(&delegation->lock); 774 if (ret) 775 nfs_clear_verifier_delegated(inode); 776 } 777out: 778 rcu_read_unlock(); 779 nfs_end_delegation_return(inode, ret, 0); 780} 781 782/** 783 * nfs4_inode_make_writeable 784 * @inode: pointer to inode 785 * 786 * Make the inode writeable by returning the delegation if necessary 787 * 788 * Returns zero on success, or a negative errno value. 789 */ 790int nfs4_inode_make_writeable(struct inode *inode) 791{ 792 struct nfs_delegation *delegation; 793 794 rcu_read_lock(); 795 delegation = nfs4_get_valid_delegation(inode); 796 if (delegation == NULL || 797 (nfs4_has_session(NFS_SERVER(inode)->nfs_client) && 798 (delegation->type & FMODE_WRITE))) { 799 rcu_read_unlock(); 800 return 0; 801 } 802 rcu_read_unlock(); 803 return nfs4_inode_return_delegation(inode); 804} 805 806static void nfs_mark_return_if_closed_delegation(struct nfs_server *server, 807 struct nfs_delegation *delegation) 808{ 809 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags); 810 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state); 811} 812 813static bool nfs_server_mark_return_all_delegations(struct nfs_server *server) 814{ 815 struct nfs_delegation *delegation; 816 bool ret = false; 817 818 list_for_each_entry_rcu(delegation, &server->delegations, super_list) { 819 nfs_mark_return_delegation(server, delegation); 820 ret = true; 821 } 822 return ret; 823} 824 825static void nfs_client_mark_return_all_delegations(struct nfs_client *clp) 826{ 827 struct nfs_server *server; 828 829 rcu_read_lock(); 830 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) 831 nfs_server_mark_return_all_delegations(server); 832 rcu_read_unlock(); 833} 834 835static void nfs_delegation_run_state_manager(struct nfs_client *clp) 836{ 837 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state)) 838 nfs4_schedule_state_manager(clp); 839} 840 841/** 842 * nfs_expire_all_delegations 843 * @clp: client to process 844 * 845 */ 846void nfs_expire_all_delegations(struct nfs_client *clp) 847{ 848 nfs_client_mark_return_all_delegations(clp); 849 nfs_delegation_run_state_manager(clp); 850} 851 852/** 853 * nfs_super_return_all_delegations - return delegations for one superblock 854 * @server: pointer to nfs_server to process 855 * 856 */ 857void nfs_server_return_all_delegations(struct nfs_server *server) 858{ 859 struct nfs_client *clp = server->nfs_client; 860 bool need_wait; 861 862 if (clp == NULL) 863 return; 864 865 rcu_read_lock(); 866 need_wait = nfs_server_mark_return_all_delegations(server); 867 rcu_read_unlock(); 868 869 if (need_wait) { 870 nfs4_schedule_state_manager(clp); 871 nfs4_wait_clnt_recover(clp); 872 } 873} 874 875static void nfs_mark_return_unused_delegation_types(struct nfs_server *server, 876 fmode_t flags) 877{ 878 struct nfs_delegation *delegation; 879 880 list_for_each_entry_rcu(delegation, &server->delegations, super_list) { 881 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE)) 882 continue; 883 if (delegation->type & flags) 884 nfs_mark_return_if_closed_delegation(server, delegation); 885 } 886} 887 888static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp, 889 fmode_t flags) 890{ 891 struct nfs_server *server; 892 893 rcu_read_lock(); 894 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) 895 nfs_mark_return_unused_delegation_types(server, flags); 896 rcu_read_unlock(); 897} 898 899static void nfs_revoke_delegation(struct inode *inode, 900 const nfs4_stateid *stateid) 901{ 902 struct nfs_delegation *delegation; 903 nfs4_stateid tmp; 904 bool ret = false; 905 906 rcu_read_lock(); 907 delegation = rcu_dereference(NFS_I(inode)->delegation); 908 if (delegation == NULL) 909 goto out; 910 if (stateid == NULL) { 911 nfs4_stateid_copy(&tmp, &delegation->stateid); 912 stateid = &tmp; 913 } else { 914 if (!nfs4_stateid_match_other(stateid, &delegation->stateid)) 915 goto out; 916 spin_lock(&delegation->lock); 917 if (stateid->seqid) { 918 if (nfs4_stateid_is_newer(&delegation->stateid, stateid)) { 919 spin_unlock(&delegation->lock); 920 goto out; 921 } 922 delegation->stateid.seqid = stateid->seqid; 923 } 924 spin_unlock(&delegation->lock); 925 } 926 nfs_mark_delegation_revoked(delegation); 927 ret = true; 928out: 929 rcu_read_unlock(); 930 if (ret) 931 nfs_inode_find_state_and_recover(inode, stateid); 932} 933 934void nfs_remove_bad_delegation(struct inode *inode, 935 const nfs4_stateid *stateid) 936{ 937 nfs_revoke_delegation(inode, stateid); 938} 939EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation); 940 941void nfs_delegation_mark_returned(struct inode *inode, 942 const nfs4_stateid *stateid) 943{ 944 struct nfs_delegation *delegation; 945 946 if (!inode) 947 return; 948 949 rcu_read_lock(); 950 delegation = rcu_dereference(NFS_I(inode)->delegation); 951 if (!delegation) 952 goto out_rcu_unlock; 953 954 spin_lock(&delegation->lock); 955 if (!nfs4_stateid_match_other(stateid, &delegation->stateid)) 956 goto out_spin_unlock; 957 if (stateid->seqid) { 958 /* If delegation->stateid is newer, dont mark as returned */ 959 if (nfs4_stateid_is_newer(&delegation->stateid, stateid)) 960 goto out_clear_returning; 961 if (delegation->stateid.seqid != stateid->seqid) 962 delegation->stateid.seqid = stateid->seqid; 963 } 964 965 nfs_mark_delegation_revoked(delegation); 966 967out_clear_returning: 968 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags); 969out_spin_unlock: 970 spin_unlock(&delegation->lock); 971out_rcu_unlock: 972 rcu_read_unlock(); 973 974 nfs_inode_find_state_and_recover(inode, stateid); 975} 976 977/** 978 * nfs_expire_unused_delegation_types 979 * @clp: client to process 980 * @flags: delegation types to expire 981 * 982 */ 983void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags) 984{ 985 nfs_client_mark_return_unused_delegation_types(clp, flags); 986 nfs_delegation_run_state_manager(clp); 987} 988 989static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server) 990{ 991 struct nfs_delegation *delegation; 992 993 list_for_each_entry_rcu(delegation, &server->delegations, super_list) { 994 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags)) 995 continue; 996 nfs_mark_return_if_closed_delegation(server, delegation); 997 } 998} 999 1000/** 1001 * nfs_expire_unreferenced_delegations - Eliminate unused delegations 1002 * @clp: nfs_client to process 1003 * 1004 */ 1005void nfs_expire_unreferenced_delegations(struct nfs_client *clp) 1006{ 1007 struct nfs_server *server; 1008 1009 rcu_read_lock(); 1010 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) 1011 nfs_mark_return_unreferenced_delegations(server); 1012 rcu_read_unlock(); 1013 1014 nfs_delegation_run_state_manager(clp); 1015} 1016 1017/** 1018 * nfs_async_inode_return_delegation - asynchronously return a delegation 1019 * @inode: inode to process 1020 * @stateid: state ID information 1021 * 1022 * Returns zero on success, or a negative errno value. 1023 */ 1024int nfs_async_inode_return_delegation(struct inode *inode, 1025 const nfs4_stateid *stateid) 1026{ 1027 struct nfs_server *server = NFS_SERVER(inode); 1028 struct nfs_client *clp = server->nfs_client; 1029 struct nfs_delegation *delegation; 1030 1031 rcu_read_lock(); 1032 delegation = nfs4_get_valid_delegation(inode); 1033 if (delegation == NULL) 1034 goto out_enoent; 1035 if (stateid != NULL && 1036 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid)) 1037 goto out_enoent; 1038 nfs_mark_return_delegation(server, delegation); 1039 rcu_read_unlock(); 1040 1041 nfs_delegation_run_state_manager(clp); 1042 return 0; 1043out_enoent: 1044 rcu_read_unlock(); 1045 return -ENOENT; 1046} 1047 1048static struct inode * 1049nfs_delegation_find_inode_server(struct nfs_server *server, 1050 const struct nfs_fh *fhandle) 1051{ 1052 struct nfs_delegation *delegation; 1053 struct super_block *freeme = NULL; 1054 struct inode *res = NULL; 1055 1056 list_for_each_entry_rcu(delegation, &server->delegations, super_list) { 1057 spin_lock(&delegation->lock); 1058 if (delegation->inode != NULL && 1059 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) && 1060 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) { 1061 if (nfs_sb_active(server->super)) { 1062 freeme = server->super; 1063 res = igrab(delegation->inode); 1064 } 1065 spin_unlock(&delegation->lock); 1066 if (res != NULL) 1067 return res; 1068 if (freeme) { 1069 rcu_read_unlock(); 1070 nfs_sb_deactive(freeme); 1071 rcu_read_lock(); 1072 } 1073 return ERR_PTR(-EAGAIN); 1074 } 1075 spin_unlock(&delegation->lock); 1076 } 1077 return ERR_PTR(-ENOENT); 1078} 1079 1080/** 1081 * nfs_delegation_find_inode - retrieve the inode associated with a delegation 1082 * @clp: client state handle 1083 * @fhandle: filehandle from a delegation recall 1084 * 1085 * Returns pointer to inode matching "fhandle," or NULL if a matching inode 1086 * cannot be found. 1087 */ 1088struct inode *nfs_delegation_find_inode(struct nfs_client *clp, 1089 const struct nfs_fh *fhandle) 1090{ 1091 struct nfs_server *server; 1092 struct inode *res; 1093 1094 rcu_read_lock(); 1095 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { 1096 res = nfs_delegation_find_inode_server(server, fhandle); 1097 if (res != ERR_PTR(-ENOENT)) { 1098 rcu_read_unlock(); 1099 return res; 1100 } 1101 } 1102 rcu_read_unlock(); 1103 return ERR_PTR(-ENOENT); 1104} 1105 1106static void nfs_delegation_mark_reclaim_server(struct nfs_server *server) 1107{ 1108 struct nfs_delegation *delegation; 1109 1110 list_for_each_entry_rcu(delegation, &server->delegations, super_list) { 1111 /* 1112 * If the delegation may have been admin revoked, then we 1113 * cannot reclaim it. 1114 */ 1115 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags)) 1116 continue; 1117 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags); 1118 } 1119} 1120 1121/** 1122 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed 1123 * @clp: nfs_client to process 1124 * 1125 */ 1126void nfs_delegation_mark_reclaim(struct nfs_client *clp) 1127{ 1128 struct nfs_server *server; 1129 1130 rcu_read_lock(); 1131 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) 1132 nfs_delegation_mark_reclaim_server(server); 1133 rcu_read_unlock(); 1134} 1135 1136static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server, 1137 void __always_unused *data) 1138{ 1139 struct nfs_delegation *delegation; 1140 struct inode *inode; 1141restart: 1142 rcu_read_lock(); 1143restart_locked: 1144 list_for_each_entry_rcu(delegation, &server->delegations, super_list) { 1145 if (test_bit(NFS_DELEGATION_INODE_FREEING, 1146 &delegation->flags) || 1147 test_bit(NFS_DELEGATION_RETURNING, 1148 &delegation->flags) || 1149 test_bit(NFS_DELEGATION_NEED_RECLAIM, 1150 &delegation->flags) == 0) 1151 continue; 1152 inode = nfs_delegation_grab_inode(delegation); 1153 if (inode == NULL) 1154 goto restart_locked; 1155 delegation = nfs_start_delegation_return_locked(NFS_I(inode)); 1156 rcu_read_unlock(); 1157 if (delegation != NULL) { 1158 if (nfs_detach_delegation(NFS_I(inode), delegation, 1159 server) != NULL) 1160 nfs_free_delegation(delegation); 1161 /* Match nfs_start_delegation_return_locked */ 1162 nfs_put_delegation(delegation); 1163 } 1164 iput(inode); 1165 cond_resched(); 1166 goto restart; 1167 } 1168 rcu_read_unlock(); 1169 return 0; 1170} 1171 1172/** 1173 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done 1174 * @clp: nfs_client to process 1175 * 1176 */ 1177void nfs_delegation_reap_unclaimed(struct nfs_client *clp) 1178{ 1179 nfs_client_for_each_server(clp, nfs_server_reap_unclaimed_delegations, 1180 NULL); 1181} 1182 1183static inline bool nfs4_server_rebooted(const struct nfs_client *clp) 1184{ 1185 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) | 1186 BIT(NFS4CLNT_LEASE_EXPIRED) | 1187 BIT(NFS4CLNT_SESSION_RESET))) != 0; 1188} 1189 1190static void nfs_mark_test_expired_delegation(struct nfs_server *server, 1191 struct nfs_delegation *delegation) 1192{ 1193 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE) 1194 return; 1195 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags); 1196 set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags); 1197 set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state); 1198} 1199 1200static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server, 1201 struct inode *inode) 1202{ 1203 struct nfs_delegation *delegation; 1204 1205 rcu_read_lock(); 1206 delegation = rcu_dereference(NFS_I(inode)->delegation); 1207 if (delegation) 1208 nfs_mark_test_expired_delegation(server, delegation); 1209 rcu_read_unlock(); 1210 1211} 1212 1213static void nfs_delegation_mark_test_expired_server(struct nfs_server *server) 1214{ 1215 struct nfs_delegation *delegation; 1216 1217 list_for_each_entry_rcu(delegation, &server->delegations, super_list) 1218 nfs_mark_test_expired_delegation(server, delegation); 1219} 1220 1221/** 1222 * nfs_mark_test_expired_all_delegations - mark all delegations for testing 1223 * @clp: nfs_client to process 1224 * 1225 * Iterates through all the delegations associated with this server and 1226 * marks them as needing to be checked for validity. 1227 */ 1228void nfs_mark_test_expired_all_delegations(struct nfs_client *clp) 1229{ 1230 struct nfs_server *server; 1231 1232 rcu_read_lock(); 1233 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) 1234 nfs_delegation_mark_test_expired_server(server); 1235 rcu_read_unlock(); 1236} 1237 1238/** 1239 * nfs_test_expired_all_delegations - test all delegations for a client 1240 * @clp: nfs_client to process 1241 * 1242 * Helper for handling "recallable state revoked" status from server. 1243 */ 1244void nfs_test_expired_all_delegations(struct nfs_client *clp) 1245{ 1246 nfs_mark_test_expired_all_delegations(clp); 1247 nfs4_schedule_state_manager(clp); 1248} 1249 1250static void 1251nfs_delegation_test_free_expired(struct inode *inode, 1252 nfs4_stateid *stateid, 1253 const struct cred *cred) 1254{ 1255 struct nfs_server *server = NFS_SERVER(inode); 1256 const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops; 1257 int status; 1258 1259 if (!cred) 1260 return; 1261 status = ops->test_and_free_expired(server, stateid, cred); 1262 if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID) 1263 nfs_remove_bad_delegation(inode, stateid); 1264} 1265 1266static int nfs_server_reap_expired_delegations(struct nfs_server *server, 1267 void __always_unused *data) 1268{ 1269 struct nfs_delegation *delegation; 1270 struct inode *inode; 1271 const struct cred *cred; 1272 nfs4_stateid stateid; 1273restart: 1274 rcu_read_lock(); 1275restart_locked: 1276 list_for_each_entry_rcu(delegation, &server->delegations, super_list) { 1277 if (test_bit(NFS_DELEGATION_INODE_FREEING, 1278 &delegation->flags) || 1279 test_bit(NFS_DELEGATION_RETURNING, 1280 &delegation->flags) || 1281 test_bit(NFS_DELEGATION_TEST_EXPIRED, 1282 &delegation->flags) == 0) 1283 continue; 1284 inode = nfs_delegation_grab_inode(delegation); 1285 if (inode == NULL) 1286 goto restart_locked; 1287 spin_lock(&delegation->lock); 1288 cred = get_cred_rcu(delegation->cred); 1289 nfs4_stateid_copy(&stateid, &delegation->stateid); 1290 spin_unlock(&delegation->lock); 1291 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags); 1292 rcu_read_unlock(); 1293 nfs_delegation_test_free_expired(inode, &stateid, cred); 1294 put_cred(cred); 1295 if (!nfs4_server_rebooted(server->nfs_client)) { 1296 iput(inode); 1297 cond_resched(); 1298 goto restart; 1299 } 1300 nfs_inode_mark_test_expired_delegation(server,inode); 1301 iput(inode); 1302 return -EAGAIN; 1303 } 1304 rcu_read_unlock(); 1305 return 0; 1306} 1307 1308/** 1309 * nfs_reap_expired_delegations - reap expired delegations 1310 * @clp: nfs_client to process 1311 * 1312 * Iterates through all the delegations associated with this server and 1313 * checks if they have may have been revoked. This function is usually 1314 * expected to be called in cases where the server may have lost its 1315 * lease. 1316 */ 1317void nfs_reap_expired_delegations(struct nfs_client *clp) 1318{ 1319 nfs_client_for_each_server(clp, nfs_server_reap_expired_delegations, 1320 NULL); 1321} 1322 1323void nfs_inode_find_delegation_state_and_recover(struct inode *inode, 1324 const nfs4_stateid *stateid) 1325{ 1326 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client; 1327 struct nfs_delegation *delegation; 1328 bool found = false; 1329 1330 rcu_read_lock(); 1331 delegation = rcu_dereference(NFS_I(inode)->delegation); 1332 if (delegation && 1333 nfs4_stateid_match_or_older(&delegation->stateid, stateid) && 1334 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) { 1335 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation); 1336 found = true; 1337 } 1338 rcu_read_unlock(); 1339 if (found) 1340 nfs4_schedule_state_manager(clp); 1341} 1342 1343/** 1344 * nfs_delegations_present - check for existence of delegations 1345 * @clp: client state handle 1346 * 1347 * Returns one if there are any nfs_delegation structures attached 1348 * to this nfs_client. 1349 */ 1350int nfs_delegations_present(struct nfs_client *clp) 1351{ 1352 struct nfs_server *server; 1353 int ret = 0; 1354 1355 rcu_read_lock(); 1356 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) 1357 if (!list_empty(&server->delegations)) { 1358 ret = 1; 1359 break; 1360 } 1361 rcu_read_unlock(); 1362 return ret; 1363} 1364 1365/** 1366 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid 1367 * @dst: stateid to refresh 1368 * @inode: inode to check 1369 * 1370 * Returns "true" and updates "dst->seqid" * if inode had a delegation 1371 * that matches our delegation stateid. Otherwise "false" is returned. 1372 */ 1373bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode) 1374{ 1375 struct nfs_delegation *delegation; 1376 bool ret = false; 1377 if (!inode) 1378 goto out; 1379 1380 rcu_read_lock(); 1381 delegation = rcu_dereference(NFS_I(inode)->delegation); 1382 if (delegation != NULL && 1383 nfs4_stateid_match_other(dst, &delegation->stateid) && 1384 nfs4_stateid_is_newer(&delegation->stateid, dst) && 1385 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) { 1386 dst->seqid = delegation->stateid.seqid; 1387 ret = true; 1388 } 1389 rcu_read_unlock(); 1390out: 1391 return ret; 1392} 1393 1394/** 1395 * nfs4_copy_delegation_stateid - Copy inode's state ID information 1396 * @inode: inode to check 1397 * @flags: delegation type requirement 1398 * @dst: stateid data structure to fill in 1399 * @cred: optional argument to retrieve credential 1400 * 1401 * Returns "true" and fills in "dst->data" * if inode had a delegation, 1402 * otherwise "false" is returned. 1403 */ 1404bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags, 1405 nfs4_stateid *dst, const struct cred **cred) 1406{ 1407 struct nfs_inode *nfsi = NFS_I(inode); 1408 struct nfs_delegation *delegation; 1409 bool ret = false; 1410 1411 flags &= FMODE_READ|FMODE_WRITE; 1412 rcu_read_lock(); 1413 delegation = rcu_dereference(nfsi->delegation); 1414 if (!delegation) 1415 goto out; 1416 spin_lock(&delegation->lock); 1417 ret = nfs4_is_valid_delegation(delegation, flags); 1418 if (ret) { 1419 nfs4_stateid_copy(dst, &delegation->stateid); 1420 nfs_mark_delegation_referenced(delegation); 1421 if (cred) 1422 *cred = get_cred(delegation->cred); 1423 } 1424 spin_unlock(&delegation->lock); 1425out: 1426 rcu_read_unlock(); 1427 return ret; 1428} 1429 1430/** 1431 * nfs4_delegation_flush_on_close - Check if we must flush file on close 1432 * @inode: inode to check 1433 * 1434 * This function checks the number of outstanding writes to the file 1435 * against the delegation 'space_limit' field to see if 1436 * the spec requires us to flush the file on close. 1437 */ 1438bool nfs4_delegation_flush_on_close(const struct inode *inode) 1439{ 1440 struct nfs_inode *nfsi = NFS_I(inode); 1441 struct nfs_delegation *delegation; 1442 bool ret = true; 1443 1444 rcu_read_lock(); 1445 delegation = rcu_dereference(nfsi->delegation); 1446 if (delegation == NULL || !(delegation->type & FMODE_WRITE)) 1447 goto out; 1448 if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit) 1449 ret = false; 1450out: 1451 rcu_read_unlock(); 1452 return ret; 1453} 1454 1455module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644); 1456