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