1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/fs/nfs/dir.c 4 * 5 * Copyright (C) 1992 Rick Sladkey 6 * 7 * nfs directory handling functions 8 * 9 * 10 Apr 1996 Added silly rename for unlink --okir 10 * 28 Sep 1996 Improved directory cache --okir 11 * 23 Aug 1997 Claus Heine claus@momo.math.rwth-aachen.de 12 * Re-implemented silly rename for unlink, newly implemented 13 * silly rename for nfs_rename() following the suggestions 14 * of Olaf Kirch (okir) found in this file. 15 * Following Linus comments on my original hack, this version 16 * depends only on the dcache stuff and doesn't touch the inode 17 * layer (iput() and friends). 18 * 6 Jun 1999 Cache readdir lookups in the page cache. -DaveM 19 */ 20 21 #include <linux/module.h> 22 #include <linux/time.h> 23 #include <linux/errno.h> 24 #include <linux/stat.h> 25 #include <linux/fcntl.h> 26 #include <linux/string.h> 27 #include <linux/kernel.h> 28 #include <linux/slab.h> 29 #include <linux/mm.h> 30 #include <linux/sunrpc/clnt.h> 31 #include <linux/nfs_fs.h> 32 #include <linux/nfs_mount.h> 33 #include <linux/pagemap.h> 34 #include <linux/pagevec.h> 35 #include <linux/namei.h> 36 #include <linux/mount.h> 37 #include <linux/swap.h> 38 #include <linux/sched.h> 39 #include <linux/kmemleak.h> 40 #include <linux/xattr.h> 41 42 #include "delegation.h" 43 #include "iostat.h" 44 #include "internal.h" 45 #include "fscache.h" 46 47 #include "nfstrace.h" 48 49 /* #define NFS_DEBUG_VERBOSE 1 */ 50 51 static int nfs_opendir(struct inode *, struct file *); 52 static int nfs_closedir(struct inode *, struct file *); 53 static int nfs_readdir(struct file *, struct dir_context *); 54 static int nfs_fsync_dir(struct file *, loff_t, loff_t, int); 55 static loff_t nfs_llseek_dir(struct file *, loff_t, int); 56 static void nfs_readdir_clear_array(struct page*); 57 58 const struct file_operations nfs_dir_operations = { 59 .llseek = nfs_llseek_dir, 60 .read = generic_read_dir, 61 .iterate_shared = nfs_readdir, 62 .open = nfs_opendir, 63 .release = nfs_closedir, 64 .fsync = nfs_fsync_dir, 65 }; 66 67 const struct address_space_operations nfs_dir_aops = { 68 .freepage = nfs_readdir_clear_array, 69 }; 70 71 static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir) 72 { 73 struct nfs_inode *nfsi = NFS_I(dir); 74 struct nfs_open_dir_context *ctx; 75 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); 76 if (ctx != NULL) { 77 ctx->duped = 0; 78 ctx->attr_gencount = nfsi->attr_gencount; 79 ctx->dir_cookie = 0; 80 ctx->dup_cookie = 0; 81 spin_lock(&dir->i_lock); 82 if (list_empty(&nfsi->open_files) && 83 (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER)) 84 nfsi->cache_validity |= NFS_INO_INVALID_DATA | 85 NFS_INO_REVAL_FORCED; 86 list_add(&ctx->list, &nfsi->open_files); 87 spin_unlock(&dir->i_lock); 88 return ctx; 89 } 90 return ERR_PTR(-ENOMEM); 91 } 92 93 static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx) 94 { 95 spin_lock(&dir->i_lock); 96 list_del(&ctx->list); 97 spin_unlock(&dir->i_lock); 98 kfree(ctx); 99 } 100 101 /* 102 * Open file 103 */ 104 static int 105 nfs_opendir(struct inode *inode, struct file *filp) 106 { 107 int res = 0; 108 struct nfs_open_dir_context *ctx; 109 110 dfprintk(FILE, "NFS: open dir(%pD2)\n", filp); 111 112 nfs_inc_stats(inode, NFSIOS_VFSOPEN); 113 114 ctx = alloc_nfs_open_dir_context(inode); 115 if (IS_ERR(ctx)) { 116 res = PTR_ERR(ctx); 117 goto out; 118 } 119 filp->private_data = ctx; 120 out: 121 return res; 122 } 123 124 static int 125 nfs_closedir(struct inode *inode, struct file *filp) 126 { 127 put_nfs_open_dir_context(file_inode(filp), filp->private_data); 128 return 0; 129 } 130 131 struct nfs_cache_array_entry { 132 u64 cookie; 133 u64 ino; 134 const char *name; 135 unsigned int name_len; 136 unsigned char d_type; 137 }; 138 139 struct nfs_cache_array { 140 u64 last_cookie; 141 unsigned int size; 142 unsigned char page_full : 1, 143 page_is_eof : 1, 144 cookies_are_ordered : 1; 145 struct nfs_cache_array_entry array[]; 146 }; 147 148 struct nfs_readdir_descriptor { 149 struct file *file; 150 struct page *page; 151 struct dir_context *ctx; 152 pgoff_t page_index; 153 u64 dir_cookie; 154 u64 last_cookie; 155 u64 dup_cookie; 156 loff_t current_index; 157 loff_t prev_index; 158 159 __be32 verf[NFS_DIR_VERIFIER_SIZE]; 160 unsigned long dir_verifier; 161 unsigned long timestamp; 162 unsigned long gencount; 163 unsigned long attr_gencount; 164 unsigned int cache_entry_index; 165 signed char duped; 166 bool plus; 167 bool eof; 168 }; 169 170 static void nfs_readdir_array_init(struct nfs_cache_array *array) 171 { 172 memset(array, 0, sizeof(struct nfs_cache_array)); 173 } 174 175 static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie) 176 { 177 struct nfs_cache_array *array; 178 179 array = kmap_atomic(page); 180 nfs_readdir_array_init(array); 181 array->last_cookie = last_cookie; 182 array->cookies_are_ordered = 1; 183 kunmap_atomic(array); 184 } 185 186 /* 187 * we are freeing strings created by nfs_add_to_readdir_array() 188 */ 189 static 190 void nfs_readdir_clear_array(struct page *page) 191 { 192 struct nfs_cache_array *array; 193 int i; 194 195 array = kmap_atomic(page); 196 for (i = 0; i < array->size; i++) 197 kfree(array->array[i].name); 198 nfs_readdir_array_init(array); 199 kunmap_atomic(array); 200 } 201 202 static struct page * 203 nfs_readdir_page_array_alloc(u64 last_cookie, gfp_t gfp_flags) 204 { 205 struct page *page = alloc_page(gfp_flags); 206 if (page) 207 nfs_readdir_page_init_array(page, last_cookie); 208 return page; 209 } 210 211 static void nfs_readdir_page_array_free(struct page *page) 212 { 213 if (page) { 214 nfs_readdir_clear_array(page); 215 put_page(page); 216 } 217 } 218 219 static void nfs_readdir_array_set_eof(struct nfs_cache_array *array) 220 { 221 array->page_is_eof = 1; 222 array->page_full = 1; 223 } 224 225 static bool nfs_readdir_array_is_full(struct nfs_cache_array *array) 226 { 227 return array->page_full; 228 } 229 230 /* 231 * the caller is responsible for freeing qstr.name 232 * when called by nfs_readdir_add_to_array, the strings will be freed in 233 * nfs_clear_readdir_array() 234 */ 235 static const char *nfs_readdir_copy_name(const char *name, unsigned int len) 236 { 237 const char *ret = kmemdup_nul(name, len, GFP_KERNEL); 238 239 /* 240 * Avoid a kmemleak false positive. The pointer to the name is stored 241 * in a page cache page which kmemleak does not scan. 242 */ 243 if (ret != NULL) 244 kmemleak_not_leak(ret); 245 return ret; 246 } 247 248 /* 249 * Check that the next array entry lies entirely within the page bounds 250 */ 251 static int nfs_readdir_array_can_expand(struct nfs_cache_array *array) 252 { 253 struct nfs_cache_array_entry *cache_entry; 254 255 if (array->page_full) 256 return -ENOSPC; 257 cache_entry = &array->array[array->size + 1]; 258 if ((char *)cache_entry - (char *)array > PAGE_SIZE) { 259 array->page_full = 1; 260 return -ENOSPC; 261 } 262 return 0; 263 } 264 265 static 266 int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page) 267 { 268 struct nfs_cache_array *array; 269 struct nfs_cache_array_entry *cache_entry; 270 const char *name; 271 int ret; 272 273 name = nfs_readdir_copy_name(entry->name, entry->len); 274 if (!name) 275 return -ENOMEM; 276 277 array = kmap_atomic(page); 278 ret = nfs_readdir_array_can_expand(array); 279 if (ret) { 280 kfree(name); 281 goto out; 282 } 283 284 cache_entry = &array->array[array->size]; 285 cache_entry->cookie = entry->prev_cookie; 286 cache_entry->ino = entry->ino; 287 cache_entry->d_type = entry->d_type; 288 cache_entry->name_len = entry->len; 289 cache_entry->name = name; 290 array->last_cookie = entry->cookie; 291 if (array->last_cookie <= cache_entry->cookie) 292 array->cookies_are_ordered = 0; 293 array->size++; 294 if (entry->eof != 0) 295 nfs_readdir_array_set_eof(array); 296 out: 297 kunmap_atomic(array); 298 return ret; 299 } 300 301 static struct page *nfs_readdir_page_get_locked(struct address_space *mapping, 302 pgoff_t index, u64 last_cookie) 303 { 304 struct page *page; 305 306 page = grab_cache_page(mapping, index); 307 if (page && !PageUptodate(page)) { 308 nfs_readdir_page_init_array(page, last_cookie); 309 if (invalidate_inode_pages2_range(mapping, index + 1, -1) < 0) 310 nfs_zap_mapping(mapping->host, mapping); 311 SetPageUptodate(page); 312 } 313 314 return page; 315 } 316 317 static u64 nfs_readdir_page_last_cookie(struct page *page) 318 { 319 struct nfs_cache_array *array; 320 u64 ret; 321 322 array = kmap_atomic(page); 323 ret = array->last_cookie; 324 kunmap_atomic(array); 325 return ret; 326 } 327 328 static bool nfs_readdir_page_needs_filling(struct page *page) 329 { 330 struct nfs_cache_array *array; 331 bool ret; 332 333 array = kmap_atomic(page); 334 ret = !nfs_readdir_array_is_full(array); 335 kunmap_atomic(array); 336 return ret; 337 } 338 339 static void nfs_readdir_page_set_eof(struct page *page) 340 { 341 struct nfs_cache_array *array; 342 343 array = kmap_atomic(page); 344 nfs_readdir_array_set_eof(array); 345 kunmap_atomic(array); 346 } 347 348 static void nfs_readdir_page_unlock_and_put(struct page *page) 349 { 350 unlock_page(page); 351 put_page(page); 352 } 353 354 static struct page *nfs_readdir_page_get_next(struct address_space *mapping, 355 pgoff_t index, u64 cookie) 356 { 357 struct page *page; 358 359 page = nfs_readdir_page_get_locked(mapping, index, cookie); 360 if (page) { 361 if (nfs_readdir_page_last_cookie(page) == cookie) 362 return page; 363 nfs_readdir_page_unlock_and_put(page); 364 } 365 return NULL; 366 } 367 368 static inline 369 int is_32bit_api(void) 370 { 371 #ifdef CONFIG_COMPAT 372 return in_compat_syscall(); 373 #else 374 return (BITS_PER_LONG == 32); 375 #endif 376 } 377 378 static 379 bool nfs_readdir_use_cookie(const struct file *filp) 380 { 381 if ((filp->f_mode & FMODE_32BITHASH) || 382 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) 383 return false; 384 return true; 385 } 386 387 static int nfs_readdir_search_for_pos(struct nfs_cache_array *array, 388 struct nfs_readdir_descriptor *desc) 389 { 390 loff_t diff = desc->ctx->pos - desc->current_index; 391 unsigned int index; 392 393 if (diff < 0) 394 goto out_eof; 395 if (diff >= array->size) { 396 if (array->page_is_eof) 397 goto out_eof; 398 return -EAGAIN; 399 } 400 401 index = (unsigned int)diff; 402 desc->dir_cookie = array->array[index].cookie; 403 desc->cache_entry_index = index; 404 return 0; 405 out_eof: 406 desc->eof = true; 407 return -EBADCOOKIE; 408 } 409 410 static bool 411 nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi) 412 { 413 if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA)) 414 return false; 415 smp_rmb(); 416 return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags); 417 } 418 419 static bool nfs_readdir_array_cookie_in_range(struct nfs_cache_array *array, 420 u64 cookie) 421 { 422 if (!array->cookies_are_ordered) 423 return true; 424 /* Optimisation for monotonically increasing cookies */ 425 if (cookie >= array->last_cookie) 426 return false; 427 if (array->size && cookie < array->array[0].cookie) 428 return false; 429 return true; 430 } 431 432 static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, 433 struct nfs_readdir_descriptor *desc) 434 { 435 int i; 436 loff_t new_pos; 437 int status = -EAGAIN; 438 439 if (!nfs_readdir_array_cookie_in_range(array, desc->dir_cookie)) 440 goto check_eof; 441 442 for (i = 0; i < array->size; i++) { 443 if (array->array[i].cookie == desc->dir_cookie) { 444 struct nfs_inode *nfsi = NFS_I(file_inode(desc->file)); 445 446 new_pos = desc->current_index + i; 447 if (desc->attr_gencount != nfsi->attr_gencount || 448 !nfs_readdir_inode_mapping_valid(nfsi)) { 449 desc->duped = 0; 450 desc->attr_gencount = nfsi->attr_gencount; 451 } else if (new_pos < desc->prev_index) { 452 if (desc->duped > 0 453 && desc->dup_cookie == desc->dir_cookie) { 454 if (printk_ratelimit()) { 455 pr_notice("NFS: directory %pD2 contains a readdir loop." 456 "Please contact your server vendor. " 457 "The file: %s has duplicate cookie %llu\n", 458 desc->file, array->array[i].name, desc->dir_cookie); 459 } 460 status = -ELOOP; 461 goto out; 462 } 463 desc->dup_cookie = desc->dir_cookie; 464 desc->duped = -1; 465 } 466 if (nfs_readdir_use_cookie(desc->file)) 467 desc->ctx->pos = desc->dir_cookie; 468 else 469 desc->ctx->pos = new_pos; 470 desc->prev_index = new_pos; 471 desc->cache_entry_index = i; 472 return 0; 473 } 474 } 475 check_eof: 476 if (array->page_is_eof) { 477 status = -EBADCOOKIE; 478 if (desc->dir_cookie == array->last_cookie) 479 desc->eof = true; 480 } 481 out: 482 return status; 483 } 484 485 static int nfs_readdir_search_array(struct nfs_readdir_descriptor *desc) 486 { 487 struct nfs_cache_array *array; 488 int status; 489 490 array = kmap_atomic(desc->page); 491 492 if (desc->dir_cookie == 0) 493 status = nfs_readdir_search_for_pos(array, desc); 494 else 495 status = nfs_readdir_search_for_cookie(array, desc); 496 497 if (status == -EAGAIN) { 498 desc->last_cookie = array->last_cookie; 499 desc->current_index += array->size; 500 desc->page_index++; 501 } 502 kunmap_atomic(array); 503 return status; 504 } 505 506 /* Fill a page with xdr information before transferring to the cache page */ 507 static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc, 508 __be32 *verf, u64 cookie, 509 struct page **pages, size_t bufsize, 510 __be32 *verf_res) 511 { 512 struct inode *inode = file_inode(desc->file); 513 struct nfs_readdir_arg arg = { 514 .dentry = file_dentry(desc->file), 515 .cred = desc->file->f_cred, 516 .verf = verf, 517 .cookie = cookie, 518 .pages = pages, 519 .page_len = bufsize, 520 .plus = desc->plus, 521 }; 522 struct nfs_readdir_res res = { 523 .verf = verf_res, 524 }; 525 unsigned long timestamp, gencount; 526 int error; 527 528 again: 529 timestamp = jiffies; 530 gencount = nfs_inc_attr_generation_counter(); 531 desc->dir_verifier = nfs_save_change_attribute(inode); 532 error = NFS_PROTO(inode)->readdir(&arg, &res); 533 if (error < 0) { 534 /* We requested READDIRPLUS, but the server doesn't grok it */ 535 if (error == -ENOTSUPP && desc->plus) { 536 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; 537 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 538 desc->plus = arg.plus = false; 539 goto again; 540 } 541 goto error; 542 } 543 desc->timestamp = timestamp; 544 desc->gencount = gencount; 545 error: 546 return error; 547 } 548 549 static int xdr_decode(struct nfs_readdir_descriptor *desc, 550 struct nfs_entry *entry, struct xdr_stream *xdr) 551 { 552 struct inode *inode = file_inode(desc->file); 553 int error; 554 555 error = NFS_PROTO(inode)->decode_dirent(xdr, entry, desc->plus); 556 if (error) 557 return error; 558 entry->fattr->time_start = desc->timestamp; 559 entry->fattr->gencount = desc->gencount; 560 return 0; 561 } 562 563 /* Match file and dirent using either filehandle or fileid 564 * Note: caller is responsible for checking the fsid 565 */ 566 static 567 int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) 568 { 569 struct inode *inode; 570 struct nfs_inode *nfsi; 571 572 if (d_really_is_negative(dentry)) 573 return 0; 574 575 inode = d_inode(dentry); 576 if (is_bad_inode(inode) || NFS_STALE(inode)) 577 return 0; 578 579 nfsi = NFS_I(inode); 580 if (entry->fattr->fileid != nfsi->fileid) 581 return 0; 582 if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0) 583 return 0; 584 return 1; 585 } 586 587 static 588 bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx) 589 { 590 if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS)) 591 return false; 592 if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags)) 593 return true; 594 if (ctx->pos == 0) 595 return true; 596 return false; 597 } 598 599 /* 600 * This function is called by the lookup and getattr code to request the 601 * use of readdirplus to accelerate any future lookups in the same 602 * directory. 603 */ 604 void nfs_advise_use_readdirplus(struct inode *dir) 605 { 606 struct nfs_inode *nfsi = NFS_I(dir); 607 608 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && 609 !list_empty(&nfsi->open_files)) 610 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); 611 } 612 613 /* 614 * This function is mainly for use by nfs_getattr(). 615 * 616 * If this is an 'ls -l', we want to force use of readdirplus. 617 * Do this by checking if there is an active file descriptor 618 * and calling nfs_advise_use_readdirplus, then forcing a 619 * cache flush. 620 */ 621 void nfs_force_use_readdirplus(struct inode *dir) 622 { 623 struct nfs_inode *nfsi = NFS_I(dir); 624 625 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && 626 !list_empty(&nfsi->open_files)) { 627 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); 628 invalidate_mapping_pages(dir->i_mapping, 629 nfsi->page_index + 1, -1); 630 } 631 } 632 633 static 634 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry, 635 unsigned long dir_verifier) 636 { 637 struct qstr filename = QSTR_INIT(entry->name, entry->len); 638 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 639 struct dentry *dentry; 640 struct dentry *alias; 641 struct inode *inode; 642 int status; 643 644 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID)) 645 return; 646 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID)) 647 return; 648 if (filename.len == 0) 649 return; 650 /* Validate that the name doesn't contain any illegal '\0' */ 651 if (strnlen(filename.name, filename.len) != filename.len) 652 return; 653 /* ...or '/' */ 654 if (strnchr(filename.name, filename.len, '/')) 655 return; 656 if (filename.name[0] == '.') { 657 if (filename.len == 1) 658 return; 659 if (filename.len == 2 && filename.name[1] == '.') 660 return; 661 } 662 filename.hash = full_name_hash(parent, filename.name, filename.len); 663 664 dentry = d_lookup(parent, &filename); 665 again: 666 if (!dentry) { 667 dentry = d_alloc_parallel(parent, &filename, &wq); 668 if (IS_ERR(dentry)) 669 return; 670 } 671 if (!d_in_lookup(dentry)) { 672 /* Is there a mountpoint here? If so, just exit */ 673 if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid, 674 &entry->fattr->fsid)) 675 goto out; 676 if (nfs_same_file(dentry, entry)) { 677 if (!entry->fh->size) 678 goto out; 679 nfs_set_verifier(dentry, dir_verifier); 680 status = nfs_refresh_inode(d_inode(dentry), entry->fattr); 681 if (!status) 682 nfs_setsecurity(d_inode(dentry), entry->fattr, entry->label); 683 goto out; 684 } else { 685 d_invalidate(dentry); 686 dput(dentry); 687 dentry = NULL; 688 goto again; 689 } 690 } 691 if (!entry->fh->size) { 692 d_lookup_done(dentry); 693 goto out; 694 } 695 696 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label); 697 alias = d_splice_alias(inode, dentry); 698 d_lookup_done(dentry); 699 if (alias) { 700 if (IS_ERR(alias)) 701 goto out; 702 dput(dentry); 703 dentry = alias; 704 } 705 nfs_set_verifier(dentry, dir_verifier); 706 out: 707 dput(dentry); 708 } 709 710 /* Perform conversion from xdr to cache array */ 711 static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc, 712 struct nfs_entry *entry, 713 struct page **xdr_pages, 714 unsigned int buflen, 715 struct page **arrays, 716 size_t narrays) 717 { 718 struct address_space *mapping = desc->file->f_mapping; 719 struct xdr_stream stream; 720 struct xdr_buf buf; 721 struct page *scratch, *new, *page = *arrays; 722 int status; 723 724 scratch = alloc_page(GFP_KERNEL); 725 if (scratch == NULL) 726 return -ENOMEM; 727 728 xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen); 729 xdr_set_scratch_page(&stream, scratch); 730 731 do { 732 if (entry->label) 733 entry->label->len = NFS4_MAXLABELLEN; 734 735 status = xdr_decode(desc, entry, &stream); 736 if (status != 0) 737 break; 738 739 if (desc->plus) 740 nfs_prime_dcache(file_dentry(desc->file), entry, 741 desc->dir_verifier); 742 743 status = nfs_readdir_add_to_array(entry, page); 744 if (status != -ENOSPC) 745 continue; 746 747 if (page->mapping != mapping) { 748 if (!--narrays) 749 break; 750 new = nfs_readdir_page_array_alloc(entry->prev_cookie, 751 GFP_KERNEL); 752 if (!new) 753 break; 754 arrays++; 755 *arrays = page = new; 756 } else { 757 new = nfs_readdir_page_get_next(mapping, 758 page->index + 1, 759 entry->prev_cookie); 760 if (!new) 761 break; 762 if (page != *arrays) 763 nfs_readdir_page_unlock_and_put(page); 764 page = new; 765 } 766 status = nfs_readdir_add_to_array(entry, page); 767 } while (!status && !entry->eof); 768 769 switch (status) { 770 case -EBADCOOKIE: 771 if (entry->eof) { 772 nfs_readdir_page_set_eof(page); 773 status = 0; 774 } 775 break; 776 case -ENOSPC: 777 case -EAGAIN: 778 status = 0; 779 break; 780 } 781 782 if (page != *arrays) 783 nfs_readdir_page_unlock_and_put(page); 784 785 put_page(scratch); 786 return status; 787 } 788 789 static void nfs_readdir_free_pages(struct page **pages, size_t npages) 790 { 791 while (npages--) 792 put_page(pages[npages]); 793 kfree(pages); 794 } 795 796 /* 797 * nfs_readdir_alloc_pages() will allocate pages that must be freed with a call 798 * to nfs_readdir_free_pages() 799 */ 800 static struct page **nfs_readdir_alloc_pages(size_t npages) 801 { 802 struct page **pages; 803 size_t i; 804 805 pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL); 806 if (!pages) 807 return NULL; 808 for (i = 0; i < npages; i++) { 809 struct page *page = alloc_page(GFP_KERNEL); 810 if (page == NULL) 811 goto out_freepages; 812 pages[i] = page; 813 } 814 return pages; 815 816 out_freepages: 817 nfs_readdir_free_pages(pages, i); 818 return NULL; 819 } 820 821 static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc, 822 __be32 *verf_arg, __be32 *verf_res, 823 struct page **arrays, size_t narrays) 824 { 825 struct page **pages; 826 struct page *page = *arrays; 827 struct nfs_entry *entry; 828 size_t array_size; 829 struct inode *inode = file_inode(desc->file); 830 size_t dtsize = NFS_SERVER(inode)->dtsize; 831 int status = -ENOMEM; 832 833 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 834 if (!entry) 835 return -ENOMEM; 836 entry->cookie = nfs_readdir_page_last_cookie(page); 837 entry->fh = nfs_alloc_fhandle(); 838 entry->fattr = nfs_alloc_fattr(); 839 entry->server = NFS_SERVER(inode); 840 if (entry->fh == NULL || entry->fattr == NULL) 841 goto out; 842 843 entry->label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT); 844 if (IS_ERR(entry->label)) { 845 status = PTR_ERR(entry->label); 846 goto out; 847 } 848 849 array_size = (dtsize + PAGE_SIZE - 1) >> PAGE_SHIFT; 850 pages = nfs_readdir_alloc_pages(array_size); 851 if (!pages) 852 goto out_release_label; 853 854 do { 855 unsigned int pglen; 856 status = nfs_readdir_xdr_filler(desc, verf_arg, entry->cookie, 857 pages, dtsize, 858 verf_res); 859 if (status < 0) 860 break; 861 862 pglen = status; 863 if (pglen == 0) { 864 nfs_readdir_page_set_eof(page); 865 break; 866 } 867 868 status = nfs_readdir_page_filler(desc, entry, pages, pglen, 869 arrays, narrays); 870 } while (!status && nfs_readdir_page_needs_filling(page)); 871 872 nfs_readdir_free_pages(pages, array_size); 873 out_release_label: 874 nfs4_label_free(entry->label); 875 out: 876 nfs_free_fattr(entry->fattr); 877 nfs_free_fhandle(entry->fh); 878 kfree(entry); 879 return status; 880 } 881 882 static void nfs_readdir_page_put(struct nfs_readdir_descriptor *desc) 883 { 884 put_page(desc->page); 885 desc->page = NULL; 886 } 887 888 static void 889 nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc) 890 { 891 unlock_page(desc->page); 892 nfs_readdir_page_put(desc); 893 } 894 895 static struct page * 896 nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc) 897 { 898 return nfs_readdir_page_get_locked(desc->file->f_mapping, 899 desc->page_index, 900 desc->last_cookie); 901 } 902 903 /* 904 * Returns 0 if desc->dir_cookie was found on page desc->page_index 905 * and locks the page to prevent removal from the page cache. 906 */ 907 static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc) 908 { 909 struct inode *inode = file_inode(desc->file); 910 struct nfs_inode *nfsi = NFS_I(inode); 911 __be32 verf[NFS_DIR_VERIFIER_SIZE]; 912 int res; 913 914 desc->page = nfs_readdir_page_get_cached(desc); 915 if (!desc->page) 916 return -ENOMEM; 917 if (nfs_readdir_page_needs_filling(desc->page)) { 918 res = nfs_readdir_xdr_to_array(desc, nfsi->cookieverf, verf, 919 &desc->page, 1); 920 if (res < 0) { 921 nfs_readdir_page_unlock_and_put_cached(desc); 922 if (res == -EBADCOOKIE || res == -ENOTSYNC) { 923 invalidate_inode_pages2(desc->file->f_mapping); 924 desc->page_index = 0; 925 return -EAGAIN; 926 } 927 return res; 928 } 929 memcpy(nfsi->cookieverf, verf, sizeof(nfsi->cookieverf)); 930 } 931 res = nfs_readdir_search_array(desc); 932 if (res == 0) { 933 nfsi->page_index = desc->page_index; 934 return 0; 935 } 936 nfs_readdir_page_unlock_and_put_cached(desc); 937 return res; 938 } 939 940 static bool nfs_readdir_dont_search_cache(struct nfs_readdir_descriptor *desc) 941 { 942 struct address_space *mapping = desc->file->f_mapping; 943 struct inode *dir = file_inode(desc->file); 944 unsigned int dtsize = NFS_SERVER(dir)->dtsize; 945 loff_t size = i_size_read(dir); 946 947 /* 948 * Default to uncached readdir if the page cache is empty, and 949 * we're looking for a non-zero cookie in a large directory. 950 */ 951 return desc->dir_cookie != 0 && mapping->nrpages == 0 && size > dtsize; 952 } 953 954 /* Search for desc->dir_cookie from the beginning of the page cache */ 955 static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc) 956 { 957 int res; 958 959 if (nfs_readdir_dont_search_cache(desc)) 960 return -EBADCOOKIE; 961 962 do { 963 if (desc->page_index == 0) { 964 desc->current_index = 0; 965 desc->prev_index = 0; 966 desc->last_cookie = 0; 967 } 968 res = find_and_lock_cache_page(desc); 969 } while (res == -EAGAIN); 970 return res; 971 } 972 973 /* 974 * Once we've found the start of the dirent within a page: fill 'er up... 975 */ 976 static void nfs_do_filldir(struct nfs_readdir_descriptor *desc) 977 { 978 struct file *file = desc->file; 979 struct nfs_inode *nfsi = NFS_I(file_inode(file)); 980 struct nfs_cache_array *array; 981 unsigned int i = 0; 982 983 array = kmap(desc->page); 984 for (i = desc->cache_entry_index; i < array->size; i++) { 985 struct nfs_cache_array_entry *ent; 986 987 ent = &array->array[i]; 988 if (!dir_emit(desc->ctx, ent->name, ent->name_len, 989 nfs_compat_user_ino64(ent->ino), ent->d_type)) { 990 desc->eof = true; 991 break; 992 } 993 memcpy(desc->verf, nfsi->cookieverf, sizeof(desc->verf)); 994 if (i < (array->size-1)) 995 desc->dir_cookie = array->array[i+1].cookie; 996 else 997 desc->dir_cookie = array->last_cookie; 998 if (nfs_readdir_use_cookie(file)) 999 desc->ctx->pos = desc->dir_cookie; 1000 else 1001 desc->ctx->pos++; 1002 if (desc->duped != 0) 1003 desc->duped = 1; 1004 } 1005 if (array->page_is_eof) 1006 desc->eof = true; 1007 1008 kunmap(desc->page); 1009 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %llu\n", 1010 (unsigned long long)desc->dir_cookie); 1011 } 1012 1013 /* 1014 * If we cannot find a cookie in our cache, we suspect that this is 1015 * because it points to a deleted file, so we ask the server to return 1016 * whatever it thinks is the next entry. We then feed this to filldir. 1017 * If all goes well, we should then be able to find our way round the 1018 * cache on the next call to readdir_search_pagecache(); 1019 * 1020 * NOTE: we cannot add the anonymous page to the pagecache because 1021 * the data it contains might not be page aligned. Besides, 1022 * we should already have a complete representation of the 1023 * directory in the page cache by the time we get here. 1024 */ 1025 static int uncached_readdir(struct nfs_readdir_descriptor *desc) 1026 { 1027 struct page **arrays; 1028 size_t i, sz = 512; 1029 __be32 verf[NFS_DIR_VERIFIER_SIZE]; 1030 int status = -ENOMEM; 1031 1032 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %llu\n", 1033 (unsigned long long)desc->dir_cookie); 1034 1035 arrays = kcalloc(sz, sizeof(*arrays), GFP_KERNEL); 1036 if (!arrays) 1037 goto out; 1038 arrays[0] = nfs_readdir_page_array_alloc(desc->dir_cookie, GFP_KERNEL); 1039 if (!arrays[0]) 1040 goto out; 1041 1042 desc->page_index = 0; 1043 desc->last_cookie = desc->dir_cookie; 1044 desc->duped = 0; 1045 1046 status = nfs_readdir_xdr_to_array(desc, desc->verf, verf, arrays, sz); 1047 1048 for (i = 0; !desc->eof && i < sz && arrays[i]; i++) { 1049 desc->page = arrays[i]; 1050 nfs_do_filldir(desc); 1051 } 1052 desc->page = NULL; 1053 1054 1055 for (i = 0; i < sz && arrays[i]; i++) 1056 nfs_readdir_page_array_free(arrays[i]); 1057 out: 1058 kfree(arrays); 1059 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status); 1060 return status; 1061 } 1062 1063 /* The file offset position represents the dirent entry number. A 1064 last cookie cache takes care of the common case of reading the 1065 whole directory. 1066 */ 1067 static int nfs_readdir(struct file *file, struct dir_context *ctx) 1068 { 1069 struct dentry *dentry = file_dentry(file); 1070 struct inode *inode = d_inode(dentry); 1071 struct nfs_open_dir_context *dir_ctx = file->private_data; 1072 struct nfs_readdir_descriptor *desc; 1073 int res; 1074 1075 dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n", 1076 file, (long long)ctx->pos); 1077 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); 1078 1079 /* 1080 * ctx->pos points to the dirent entry number. 1081 * *desc->dir_cookie has the cookie for the next entry. We have 1082 * to either find the entry with the appropriate number or 1083 * revalidate the cookie. 1084 */ 1085 if (ctx->pos == 0 || nfs_attribute_cache_expired(inode)) { 1086 res = nfs_revalidate_mapping(inode, file->f_mapping); 1087 if (res < 0) 1088 goto out; 1089 } 1090 1091 res = -ENOMEM; 1092 desc = kzalloc(sizeof(*desc), GFP_KERNEL); 1093 if (!desc) 1094 goto out; 1095 desc->file = file; 1096 desc->ctx = ctx; 1097 desc->plus = nfs_use_readdirplus(inode, ctx); 1098 1099 spin_lock(&file->f_lock); 1100 desc->dir_cookie = dir_ctx->dir_cookie; 1101 desc->dup_cookie = dir_ctx->dup_cookie; 1102 desc->duped = dir_ctx->duped; 1103 desc->attr_gencount = dir_ctx->attr_gencount; 1104 memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf)); 1105 spin_unlock(&file->f_lock); 1106 1107 do { 1108 res = readdir_search_pagecache(desc); 1109 1110 if (res == -EBADCOOKIE) { 1111 res = 0; 1112 /* This means either end of directory */ 1113 if (desc->dir_cookie && !desc->eof) { 1114 /* Or that the server has 'lost' a cookie */ 1115 res = uncached_readdir(desc); 1116 if (res == 0) 1117 continue; 1118 if (res == -EBADCOOKIE || res == -ENOTSYNC) 1119 res = 0; 1120 } 1121 break; 1122 } 1123 if (res == -ETOOSMALL && desc->plus) { 1124 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 1125 nfs_zap_caches(inode); 1126 desc->page_index = 0; 1127 desc->plus = false; 1128 desc->eof = false; 1129 continue; 1130 } 1131 if (res < 0) 1132 break; 1133 1134 nfs_do_filldir(desc); 1135 nfs_readdir_page_unlock_and_put_cached(desc); 1136 } while (!desc->eof); 1137 1138 spin_lock(&file->f_lock); 1139 dir_ctx->dir_cookie = desc->dir_cookie; 1140 dir_ctx->dup_cookie = desc->dup_cookie; 1141 dir_ctx->duped = desc->duped; 1142 dir_ctx->attr_gencount = desc->attr_gencount; 1143 memcpy(dir_ctx->verf, desc->verf, sizeof(dir_ctx->verf)); 1144 spin_unlock(&file->f_lock); 1145 1146 kfree(desc); 1147 1148 out: 1149 dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res); 1150 return res; 1151 } 1152 1153 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) 1154 { 1155 struct nfs_open_dir_context *dir_ctx = filp->private_data; 1156 1157 dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n", 1158 filp, offset, whence); 1159 1160 switch (whence) { 1161 default: 1162 return -EINVAL; 1163 case SEEK_SET: 1164 if (offset < 0) 1165 return -EINVAL; 1166 spin_lock(&filp->f_lock); 1167 break; 1168 case SEEK_CUR: 1169 if (offset == 0) 1170 return filp->f_pos; 1171 spin_lock(&filp->f_lock); 1172 offset += filp->f_pos; 1173 if (offset < 0) { 1174 spin_unlock(&filp->f_lock); 1175 return -EINVAL; 1176 } 1177 } 1178 if (offset != filp->f_pos) { 1179 filp->f_pos = offset; 1180 if (nfs_readdir_use_cookie(filp)) 1181 dir_ctx->dir_cookie = offset; 1182 else 1183 dir_ctx->dir_cookie = 0; 1184 if (offset == 0) 1185 memset(dir_ctx->verf, 0, sizeof(dir_ctx->verf)); 1186 dir_ctx->duped = 0; 1187 } 1188 spin_unlock(&filp->f_lock); 1189 return offset; 1190 } 1191 1192 /* 1193 * All directory operations under NFS are synchronous, so fsync() 1194 * is a dummy operation. 1195 */ 1196 static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end, 1197 int datasync) 1198 { 1199 dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync); 1200 1201 nfs_inc_stats(file_inode(filp), NFSIOS_VFSFSYNC); 1202 return 0; 1203 } 1204 1205 /** 1206 * nfs_force_lookup_revalidate - Mark the directory as having changed 1207 * @dir: pointer to directory inode 1208 * 1209 * This forces the revalidation code in nfs_lookup_revalidate() to do a 1210 * full lookup on all child dentries of 'dir' whenever a change occurs 1211 * on the server that might have invalidated our dcache. 1212 * 1213 * Note that we reserve bit '0' as a tag to let us know when a dentry 1214 * was revalidated while holding a delegation on its inode. 1215 * 1216 * The caller should be holding dir->i_lock 1217 */ 1218 void nfs_force_lookup_revalidate(struct inode *dir) 1219 { 1220 NFS_I(dir)->cache_change_attribute += 2; 1221 } 1222 EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate); 1223 1224 /** 1225 * nfs_verify_change_attribute - Detects NFS remote directory changes 1226 * @dir: pointer to parent directory inode 1227 * @verf: previously saved change attribute 1228 * 1229 * Return "false" if the verifiers doesn't match the change attribute. 1230 * This would usually indicate that the directory contents have changed on 1231 * the server, and that any dentries need revalidating. 1232 */ 1233 static bool nfs_verify_change_attribute(struct inode *dir, unsigned long verf) 1234 { 1235 return (verf & ~1UL) == nfs_save_change_attribute(dir); 1236 } 1237 1238 static void nfs_set_verifier_delegated(unsigned long *verf) 1239 { 1240 *verf |= 1UL; 1241 } 1242 1243 #if IS_ENABLED(CONFIG_NFS_V4) 1244 static void nfs_unset_verifier_delegated(unsigned long *verf) 1245 { 1246 *verf &= ~1UL; 1247 } 1248 #endif /* IS_ENABLED(CONFIG_NFS_V4) */ 1249 1250 static bool nfs_test_verifier_delegated(unsigned long verf) 1251 { 1252 return verf & 1; 1253 } 1254 1255 static bool nfs_verifier_is_delegated(struct dentry *dentry) 1256 { 1257 return nfs_test_verifier_delegated(dentry->d_time); 1258 } 1259 1260 static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf) 1261 { 1262 struct inode *inode = d_inode(dentry); 1263 1264 if (!nfs_verifier_is_delegated(dentry) && 1265 !nfs_verify_change_attribute(d_inode(dentry->d_parent), verf)) 1266 goto out; 1267 if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) 1268 nfs_set_verifier_delegated(&verf); 1269 out: 1270 dentry->d_time = verf; 1271 } 1272 1273 /** 1274 * nfs_set_verifier - save a parent directory verifier in the dentry 1275 * @dentry: pointer to dentry 1276 * @verf: verifier to save 1277 * 1278 * Saves the parent directory verifier in @dentry. If the inode has 1279 * a delegation, we also tag the dentry as having been revalidated 1280 * while holding a delegation so that we know we don't have to 1281 * look it up again after a directory change. 1282 */ 1283 void nfs_set_verifier(struct dentry *dentry, unsigned long verf) 1284 { 1285 1286 spin_lock(&dentry->d_lock); 1287 nfs_set_verifier_locked(dentry, verf); 1288 spin_unlock(&dentry->d_lock); 1289 } 1290 EXPORT_SYMBOL_GPL(nfs_set_verifier); 1291 1292 #if IS_ENABLED(CONFIG_NFS_V4) 1293 /** 1294 * nfs_clear_verifier_delegated - clear the dir verifier delegation tag 1295 * @inode: pointer to inode 1296 * 1297 * Iterates through the dentries in the inode alias list and clears 1298 * the tag used to indicate that the dentry has been revalidated 1299 * while holding a delegation. 1300 * This function is intended for use when the delegation is being 1301 * returned or revoked. 1302 */ 1303 void nfs_clear_verifier_delegated(struct inode *inode) 1304 { 1305 struct dentry *alias; 1306 1307 if (!inode) 1308 return; 1309 spin_lock(&inode->i_lock); 1310 hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { 1311 spin_lock(&alias->d_lock); 1312 nfs_unset_verifier_delegated(&alias->d_time); 1313 spin_unlock(&alias->d_lock); 1314 } 1315 spin_unlock(&inode->i_lock); 1316 } 1317 EXPORT_SYMBOL_GPL(nfs_clear_verifier_delegated); 1318 #endif /* IS_ENABLED(CONFIG_NFS_V4) */ 1319 1320 /* 1321 * A check for whether or not the parent directory has changed. 1322 * In the case it has, we assume that the dentries are untrustworthy 1323 * and may need to be looked up again. 1324 * If rcu_walk prevents us from performing a full check, return 0. 1325 */ 1326 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry, 1327 int rcu_walk) 1328 { 1329 if (IS_ROOT(dentry)) 1330 return 1; 1331 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE) 1332 return 0; 1333 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 1334 return 0; 1335 /* Revalidate nfsi->cache_change_attribute before we declare a match */ 1336 if (nfs_mapping_need_revalidate_inode(dir)) { 1337 if (rcu_walk) 1338 return 0; 1339 if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) 1340 return 0; 1341 } 1342 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 1343 return 0; 1344 return 1; 1345 } 1346 1347 /* 1348 * Use intent information to check whether or not we're going to do 1349 * an O_EXCL create using this path component. 1350 */ 1351 static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags) 1352 { 1353 if (NFS_PROTO(dir)->version == 2) 1354 return 0; 1355 return flags & LOOKUP_EXCL; 1356 } 1357 1358 /* 1359 * Inode and filehandle revalidation for lookups. 1360 * 1361 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, 1362 * or if the intent information indicates that we're about to open this 1363 * particular file and the "nocto" mount flag is not set. 1364 * 1365 */ 1366 static 1367 int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags) 1368 { 1369 struct nfs_server *server = NFS_SERVER(inode); 1370 int ret; 1371 1372 if (IS_AUTOMOUNT(inode)) 1373 return 0; 1374 1375 if (flags & LOOKUP_OPEN) { 1376 switch (inode->i_mode & S_IFMT) { 1377 case S_IFREG: 1378 /* A NFSv4 OPEN will revalidate later */ 1379 if (server->caps & NFS_CAP_ATOMIC_OPEN) 1380 goto out; 1381 fallthrough; 1382 case S_IFDIR: 1383 if (server->flags & NFS_MOUNT_NOCTO) 1384 break; 1385 /* NFS close-to-open cache consistency validation */ 1386 goto out_force; 1387 } 1388 } 1389 1390 /* VFS wants an on-the-wire revalidation */ 1391 if (flags & LOOKUP_REVAL) 1392 goto out_force; 1393 out: 1394 return (inode->i_nlink == 0) ? -ESTALE : 0; 1395 out_force: 1396 if (flags & LOOKUP_RCU) 1397 return -ECHILD; 1398 ret = __nfs_revalidate_inode(server, inode); 1399 if (ret != 0) 1400 return ret; 1401 goto out; 1402 } 1403 1404 static void nfs_mark_dir_for_revalidate(struct inode *inode) 1405 { 1406 spin_lock(&inode->i_lock); 1407 nfs_set_cache_invalid(inode, NFS_INO_REVAL_PAGECACHE); 1408 spin_unlock(&inode->i_lock); 1409 } 1410 1411 /* 1412 * We judge how long we want to trust negative 1413 * dentries by looking at the parent inode mtime. 1414 * 1415 * If parent mtime has changed, we revalidate, else we wait for a 1416 * period corresponding to the parent's attribute cache timeout value. 1417 * 1418 * If LOOKUP_RCU prevents us from performing a full check, return 1 1419 * suggesting a reval is needed. 1420 * 1421 * Note that when creating a new file, or looking up a rename target, 1422 * then it shouldn't be necessary to revalidate a negative dentry. 1423 */ 1424 static inline 1425 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 1426 unsigned int flags) 1427 { 1428 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) 1429 return 0; 1430 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) 1431 return 1; 1432 return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU); 1433 } 1434 1435 static int 1436 nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry, 1437 struct inode *inode, int error) 1438 { 1439 switch (error) { 1440 case 1: 1441 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n", 1442 __func__, dentry); 1443 return 1; 1444 case 0: 1445 /* 1446 * We can't d_drop the root of a disconnected tree: 1447 * its d_hash is on the s_anon list and d_drop() would hide 1448 * it from shrink_dcache_for_unmount(), leading to busy 1449 * inodes on unmount and further oopses. 1450 */ 1451 if (inode && IS_ROOT(dentry)) 1452 return 1; 1453 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n", 1454 __func__, dentry); 1455 return 0; 1456 } 1457 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n", 1458 __func__, dentry, error); 1459 return error; 1460 } 1461 1462 static int 1463 nfs_lookup_revalidate_negative(struct inode *dir, struct dentry *dentry, 1464 unsigned int flags) 1465 { 1466 int ret = 1; 1467 if (nfs_neg_need_reval(dir, dentry, flags)) { 1468 if (flags & LOOKUP_RCU) 1469 return -ECHILD; 1470 ret = 0; 1471 } 1472 return nfs_lookup_revalidate_done(dir, dentry, NULL, ret); 1473 } 1474 1475 static int 1476 nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry, 1477 struct inode *inode) 1478 { 1479 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1480 return nfs_lookup_revalidate_done(dir, dentry, inode, 1); 1481 } 1482 1483 static int 1484 nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry, 1485 struct inode *inode) 1486 { 1487 struct nfs_fh *fhandle; 1488 struct nfs_fattr *fattr; 1489 struct nfs4_label *label; 1490 unsigned long dir_verifier; 1491 int ret; 1492 1493 ret = -ENOMEM; 1494 fhandle = nfs_alloc_fhandle(); 1495 fattr = nfs_alloc_fattr(); 1496 label = nfs4_label_alloc(NFS_SERVER(inode), GFP_KERNEL); 1497 if (fhandle == NULL || fattr == NULL || IS_ERR(label)) 1498 goto out; 1499 1500 dir_verifier = nfs_save_change_attribute(dir); 1501 ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label); 1502 if (ret < 0) { 1503 switch (ret) { 1504 case -ESTALE: 1505 case -ENOENT: 1506 ret = 0; 1507 break; 1508 case -ETIMEDOUT: 1509 if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL) 1510 ret = 1; 1511 } 1512 goto out; 1513 } 1514 ret = 0; 1515 if (nfs_compare_fh(NFS_FH(inode), fhandle)) 1516 goto out; 1517 if (nfs_refresh_inode(inode, fattr) < 0) 1518 goto out; 1519 1520 nfs_setsecurity(inode, fattr, label); 1521 nfs_set_verifier(dentry, dir_verifier); 1522 1523 /* set a readdirplus hint that we had a cache miss */ 1524 nfs_force_use_readdirplus(dir); 1525 ret = 1; 1526 out: 1527 nfs_free_fattr(fattr); 1528 nfs_free_fhandle(fhandle); 1529 nfs4_label_free(label); 1530 1531 /* 1532 * If the lookup failed despite the dentry change attribute being 1533 * a match, then we should revalidate the directory cache. 1534 */ 1535 if (!ret && nfs_verify_change_attribute(dir, dentry->d_time)) 1536 nfs_mark_dir_for_revalidate(dir); 1537 return nfs_lookup_revalidate_done(dir, dentry, inode, ret); 1538 } 1539 1540 /* 1541 * This is called every time the dcache has a lookup hit, 1542 * and we should check whether we can really trust that 1543 * lookup. 1544 * 1545 * NOTE! The hit can be a negative hit too, don't assume 1546 * we have an inode! 1547 * 1548 * If the parent directory is seen to have changed, we throw out the 1549 * cached dentry and do a new lookup. 1550 */ 1551 static int 1552 nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry, 1553 unsigned int flags) 1554 { 1555 struct inode *inode; 1556 int error; 1557 1558 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); 1559 inode = d_inode(dentry); 1560 1561 if (!inode) 1562 return nfs_lookup_revalidate_negative(dir, dentry, flags); 1563 1564 if (is_bad_inode(inode)) { 1565 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", 1566 __func__, dentry); 1567 goto out_bad; 1568 } 1569 1570 if (nfs_verifier_is_delegated(dentry)) 1571 return nfs_lookup_revalidate_delegated(dir, dentry, inode); 1572 1573 /* Force a full look up iff the parent directory has changed */ 1574 if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) && 1575 nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) { 1576 error = nfs_lookup_verify_inode(inode, flags); 1577 if (error) { 1578 if (error == -ESTALE) 1579 nfs_mark_dir_for_revalidate(dir); 1580 goto out_bad; 1581 } 1582 nfs_advise_use_readdirplus(dir); 1583 goto out_valid; 1584 } 1585 1586 if (flags & LOOKUP_RCU) 1587 return -ECHILD; 1588 1589 if (NFS_STALE(inode)) 1590 goto out_bad; 1591 1592 trace_nfs_lookup_revalidate_enter(dir, dentry, flags); 1593 error = nfs_lookup_revalidate_dentry(dir, dentry, inode); 1594 trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error); 1595 return error; 1596 out_valid: 1597 return nfs_lookup_revalidate_done(dir, dentry, inode, 1); 1598 out_bad: 1599 if (flags & LOOKUP_RCU) 1600 return -ECHILD; 1601 return nfs_lookup_revalidate_done(dir, dentry, inode, 0); 1602 } 1603 1604 static int 1605 __nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags, 1606 int (*reval)(struct inode *, struct dentry *, unsigned int)) 1607 { 1608 struct dentry *parent; 1609 struct inode *dir; 1610 int ret; 1611 1612 if (flags & LOOKUP_RCU) { 1613 parent = READ_ONCE(dentry->d_parent); 1614 dir = d_inode_rcu(parent); 1615 if (!dir) 1616 return -ECHILD; 1617 ret = reval(dir, dentry, flags); 1618 if (parent != READ_ONCE(dentry->d_parent)) 1619 return -ECHILD; 1620 } else { 1621 parent = dget_parent(dentry); 1622 ret = reval(d_inode(parent), dentry, flags); 1623 dput(parent); 1624 } 1625 return ret; 1626 } 1627 1628 static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags) 1629 { 1630 return __nfs_lookup_revalidate(dentry, flags, nfs_do_lookup_revalidate); 1631 } 1632 1633 /* 1634 * A weaker form of d_revalidate for revalidating just the d_inode(dentry) 1635 * when we don't really care about the dentry name. This is called when a 1636 * pathwalk ends on a dentry that was not found via a normal lookup in the 1637 * parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals). 1638 * 1639 * In this situation, we just want to verify that the inode itself is OK 1640 * since the dentry might have changed on the server. 1641 */ 1642 static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags) 1643 { 1644 struct inode *inode = d_inode(dentry); 1645 int error = 0; 1646 1647 /* 1648 * I believe we can only get a negative dentry here in the case of a 1649 * procfs-style symlink. Just assume it's correct for now, but we may 1650 * eventually need to do something more here. 1651 */ 1652 if (!inode) { 1653 dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n", 1654 __func__, dentry); 1655 return 1; 1656 } 1657 1658 if (is_bad_inode(inode)) { 1659 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", 1660 __func__, dentry); 1661 return 0; 1662 } 1663 1664 error = nfs_lookup_verify_inode(inode, flags); 1665 dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n", 1666 __func__, inode->i_ino, error ? "invalid" : "valid"); 1667 return !error; 1668 } 1669 1670 /* 1671 * This is called from dput() when d_count is going to 0. 1672 */ 1673 static int nfs_dentry_delete(const struct dentry *dentry) 1674 { 1675 dfprintk(VFS, "NFS: dentry_delete(%pd2, %x)\n", 1676 dentry, dentry->d_flags); 1677 1678 /* Unhash any dentry with a stale inode */ 1679 if (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry))) 1680 return 1; 1681 1682 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1683 /* Unhash it, so that ->d_iput() would be called */ 1684 return 1; 1685 } 1686 if (!(dentry->d_sb->s_flags & SB_ACTIVE)) { 1687 /* Unhash it, so that ancestors of killed async unlink 1688 * files will be cleaned up during umount */ 1689 return 1; 1690 } 1691 return 0; 1692 1693 } 1694 1695 /* Ensure that we revalidate inode->i_nlink */ 1696 static void nfs_drop_nlink(struct inode *inode) 1697 { 1698 spin_lock(&inode->i_lock); 1699 /* drop the inode if we're reasonably sure this is the last link */ 1700 if (inode->i_nlink > 0) 1701 drop_nlink(inode); 1702 NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter(); 1703 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_CHANGE 1704 | NFS_INO_INVALID_CTIME 1705 | NFS_INO_INVALID_OTHER 1706 | NFS_INO_REVAL_FORCED; 1707 spin_unlock(&inode->i_lock); 1708 } 1709 1710 /* 1711 * Called when the dentry loses inode. 1712 * We use it to clean up silly-renamed files. 1713 */ 1714 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) 1715 { 1716 if (S_ISDIR(inode->i_mode)) 1717 /* drop any readdir cache as it could easily be old */ 1718 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA; 1719 1720 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1721 nfs_complete_unlink(dentry, inode); 1722 nfs_drop_nlink(inode); 1723 } 1724 iput(inode); 1725 } 1726 1727 static void nfs_d_release(struct dentry *dentry) 1728 { 1729 /* free cached devname value, if it survived that far */ 1730 if (unlikely(dentry->d_fsdata)) { 1731 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 1732 WARN_ON(1); 1733 else 1734 kfree(dentry->d_fsdata); 1735 } 1736 } 1737 1738 const struct dentry_operations nfs_dentry_operations = { 1739 .d_revalidate = nfs_lookup_revalidate, 1740 .d_weak_revalidate = nfs_weak_revalidate, 1741 .d_delete = nfs_dentry_delete, 1742 .d_iput = nfs_dentry_iput, 1743 .d_automount = nfs_d_automount, 1744 .d_release = nfs_d_release, 1745 }; 1746 EXPORT_SYMBOL_GPL(nfs_dentry_operations); 1747 1748 struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) 1749 { 1750 struct dentry *res; 1751 struct inode *inode = NULL; 1752 struct nfs_fh *fhandle = NULL; 1753 struct nfs_fattr *fattr = NULL; 1754 struct nfs4_label *label = NULL; 1755 unsigned long dir_verifier; 1756 int error; 1757 1758 dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry); 1759 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); 1760 1761 if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen)) 1762 return ERR_PTR(-ENAMETOOLONG); 1763 1764 /* 1765 * If we're doing an exclusive create, optimize away the lookup 1766 * but don't hash the dentry. 1767 */ 1768 if (nfs_is_exclusive_create(dir, flags) || flags & LOOKUP_RENAME_TARGET) 1769 return NULL; 1770 1771 res = ERR_PTR(-ENOMEM); 1772 fhandle = nfs_alloc_fhandle(); 1773 fattr = nfs_alloc_fattr(); 1774 if (fhandle == NULL || fattr == NULL) 1775 goto out; 1776 1777 label = nfs4_label_alloc(NFS_SERVER(dir), GFP_NOWAIT); 1778 if (IS_ERR(label)) 1779 goto out; 1780 1781 dir_verifier = nfs_save_change_attribute(dir); 1782 trace_nfs_lookup_enter(dir, dentry, flags); 1783 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label); 1784 if (error == -ENOENT) 1785 goto no_entry; 1786 if (error < 0) { 1787 res = ERR_PTR(error); 1788 goto out_label; 1789 } 1790 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); 1791 res = ERR_CAST(inode); 1792 if (IS_ERR(res)) 1793 goto out_label; 1794 1795 /* Notify readdir to use READDIRPLUS */ 1796 nfs_force_use_readdirplus(dir); 1797 1798 no_entry: 1799 res = d_splice_alias(inode, dentry); 1800 if (res != NULL) { 1801 if (IS_ERR(res)) 1802 goto out_label; 1803 dentry = res; 1804 } 1805 nfs_set_verifier(dentry, dir_verifier); 1806 out_label: 1807 trace_nfs_lookup_exit(dir, dentry, flags, error); 1808 nfs4_label_free(label); 1809 out: 1810 nfs_free_fattr(fattr); 1811 nfs_free_fhandle(fhandle); 1812 return res; 1813 } 1814 EXPORT_SYMBOL_GPL(nfs_lookup); 1815 1816 #if IS_ENABLED(CONFIG_NFS_V4) 1817 static int nfs4_lookup_revalidate(struct dentry *, unsigned int); 1818 1819 const struct dentry_operations nfs4_dentry_operations = { 1820 .d_revalidate = nfs4_lookup_revalidate, 1821 .d_weak_revalidate = nfs_weak_revalidate, 1822 .d_delete = nfs_dentry_delete, 1823 .d_iput = nfs_dentry_iput, 1824 .d_automount = nfs_d_automount, 1825 .d_release = nfs_d_release, 1826 }; 1827 EXPORT_SYMBOL_GPL(nfs4_dentry_operations); 1828 1829 static fmode_t flags_to_mode(int flags) 1830 { 1831 fmode_t res = (__force fmode_t)flags & FMODE_EXEC; 1832 if ((flags & O_ACCMODE) != O_WRONLY) 1833 res |= FMODE_READ; 1834 if ((flags & O_ACCMODE) != O_RDONLY) 1835 res |= FMODE_WRITE; 1836 return res; 1837 } 1838 1839 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp) 1840 { 1841 return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp); 1842 } 1843 1844 static int do_open(struct inode *inode, struct file *filp) 1845 { 1846 nfs_fscache_open_file(inode, filp); 1847 return 0; 1848 } 1849 1850 static int nfs_finish_open(struct nfs_open_context *ctx, 1851 struct dentry *dentry, 1852 struct file *file, unsigned open_flags) 1853 { 1854 int err; 1855 1856 err = finish_open(file, dentry, do_open); 1857 if (err) 1858 goto out; 1859 if (S_ISREG(file->f_path.dentry->d_inode->i_mode)) 1860 nfs_file_set_open_context(file, ctx); 1861 else 1862 err = -EOPENSTALE; 1863 out: 1864 return err; 1865 } 1866 1867 int nfs_atomic_open(struct inode *dir, struct dentry *dentry, 1868 struct file *file, unsigned open_flags, 1869 umode_t mode) 1870 { 1871 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 1872 struct nfs_open_context *ctx; 1873 struct dentry *res; 1874 struct iattr attr = { .ia_valid = ATTR_OPEN }; 1875 struct inode *inode; 1876 unsigned int lookup_flags = 0; 1877 bool switched = false; 1878 int created = 0; 1879 int err; 1880 1881 /* Expect a negative dentry */ 1882 BUG_ON(d_inode(dentry)); 1883 1884 dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n", 1885 dir->i_sb->s_id, dir->i_ino, dentry); 1886 1887 err = nfs_check_flags(open_flags); 1888 if (err) 1889 return err; 1890 1891 /* NFS only supports OPEN on regular files */ 1892 if ((open_flags & O_DIRECTORY)) { 1893 if (!d_in_lookup(dentry)) { 1894 /* 1895 * Hashed negative dentry with O_DIRECTORY: dentry was 1896 * revalidated and is fine, no need to perform lookup 1897 * again 1898 */ 1899 return -ENOENT; 1900 } 1901 lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY; 1902 goto no_open; 1903 } 1904 1905 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 1906 return -ENAMETOOLONG; 1907 1908 if (open_flags & O_CREAT) { 1909 struct nfs_server *server = NFS_SERVER(dir); 1910 1911 if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK)) 1912 mode &= ~current_umask(); 1913 1914 attr.ia_valid |= ATTR_MODE; 1915 attr.ia_mode = mode; 1916 } 1917 if (open_flags & O_TRUNC) { 1918 attr.ia_valid |= ATTR_SIZE; 1919 attr.ia_size = 0; 1920 } 1921 1922 if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) { 1923 d_drop(dentry); 1924 switched = true; 1925 dentry = d_alloc_parallel(dentry->d_parent, 1926 &dentry->d_name, &wq); 1927 if (IS_ERR(dentry)) 1928 return PTR_ERR(dentry); 1929 if (unlikely(!d_in_lookup(dentry))) 1930 return finish_no_open(file, dentry); 1931 } 1932 1933 ctx = create_nfs_open_context(dentry, open_flags, file); 1934 err = PTR_ERR(ctx); 1935 if (IS_ERR(ctx)) 1936 goto out; 1937 1938 trace_nfs_atomic_open_enter(dir, ctx, open_flags); 1939 inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, &created); 1940 if (created) 1941 file->f_mode |= FMODE_CREATED; 1942 if (IS_ERR(inode)) { 1943 err = PTR_ERR(inode); 1944 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); 1945 put_nfs_open_context(ctx); 1946 d_drop(dentry); 1947 switch (err) { 1948 case -ENOENT: 1949 d_splice_alias(NULL, dentry); 1950 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1951 break; 1952 case -EISDIR: 1953 case -ENOTDIR: 1954 goto no_open; 1955 case -ELOOP: 1956 if (!(open_flags & O_NOFOLLOW)) 1957 goto no_open; 1958 break; 1959 /* case -EINVAL: */ 1960 default: 1961 break; 1962 } 1963 goto out; 1964 } 1965 1966 err = nfs_finish_open(ctx, ctx->dentry, file, open_flags); 1967 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); 1968 put_nfs_open_context(ctx); 1969 out: 1970 if (unlikely(switched)) { 1971 d_lookup_done(dentry); 1972 dput(dentry); 1973 } 1974 return err; 1975 1976 no_open: 1977 res = nfs_lookup(dir, dentry, lookup_flags); 1978 if (switched) { 1979 d_lookup_done(dentry); 1980 if (!res) 1981 res = dentry; 1982 else 1983 dput(dentry); 1984 } 1985 if (IS_ERR(res)) 1986 return PTR_ERR(res); 1987 return finish_no_open(file, res); 1988 } 1989 EXPORT_SYMBOL_GPL(nfs_atomic_open); 1990 1991 static int 1992 nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry, 1993 unsigned int flags) 1994 { 1995 struct inode *inode; 1996 1997 if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY)) 1998 goto full_reval; 1999 if (d_mountpoint(dentry)) 2000 goto full_reval; 2001 2002 inode = d_inode(dentry); 2003 2004 /* We can't create new files in nfs_open_revalidate(), so we 2005 * optimize away revalidation of negative dentries. 2006 */ 2007 if (inode == NULL) 2008 goto full_reval; 2009 2010 if (nfs_verifier_is_delegated(dentry)) 2011 return nfs_lookup_revalidate_delegated(dir, dentry, inode); 2012 2013 /* NFS only supports OPEN on regular files */ 2014 if (!S_ISREG(inode->i_mode)) 2015 goto full_reval; 2016 2017 /* We cannot do exclusive creation on a positive dentry */ 2018 if (flags & (LOOKUP_EXCL | LOOKUP_REVAL)) 2019 goto reval_dentry; 2020 2021 /* Check if the directory changed */ 2022 if (!nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) 2023 goto reval_dentry; 2024 2025 /* Let f_op->open() actually open (and revalidate) the file */ 2026 return 1; 2027 reval_dentry: 2028 if (flags & LOOKUP_RCU) 2029 return -ECHILD; 2030 return nfs_lookup_revalidate_dentry(dir, dentry, inode); 2031 2032 full_reval: 2033 return nfs_do_lookup_revalidate(dir, dentry, flags); 2034 } 2035 2036 static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) 2037 { 2038 return __nfs_lookup_revalidate(dentry, flags, 2039 nfs4_do_lookup_revalidate); 2040 } 2041 2042 #endif /* CONFIG_NFSV4 */ 2043 2044 struct dentry * 2045 nfs_add_or_obtain(struct dentry *dentry, struct nfs_fh *fhandle, 2046 struct nfs_fattr *fattr, 2047 struct nfs4_label *label) 2048 { 2049 struct dentry *parent = dget_parent(dentry); 2050 struct inode *dir = d_inode(parent); 2051 struct inode *inode; 2052 struct dentry *d; 2053 int error; 2054 2055 d_drop(dentry); 2056 2057 if (fhandle->size == 0) { 2058 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, NULL); 2059 if (error) 2060 goto out_error; 2061 } 2062 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 2063 if (!(fattr->valid & NFS_ATTR_FATTR)) { 2064 struct nfs_server *server = NFS_SB(dentry->d_sb); 2065 error = server->nfs_client->rpc_ops->getattr(server, fhandle, 2066 fattr, NULL, NULL); 2067 if (error < 0) 2068 goto out_error; 2069 } 2070 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); 2071 d = d_splice_alias(inode, dentry); 2072 out: 2073 dput(parent); 2074 return d; 2075 out_error: 2076 d = ERR_PTR(error); 2077 goto out; 2078 } 2079 EXPORT_SYMBOL_GPL(nfs_add_or_obtain); 2080 2081 /* 2082 * Code common to create, mkdir, and mknod. 2083 */ 2084 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, 2085 struct nfs_fattr *fattr, 2086 struct nfs4_label *label) 2087 { 2088 struct dentry *d; 2089 2090 d = nfs_add_or_obtain(dentry, fhandle, fattr, label); 2091 if (IS_ERR(d)) 2092 return PTR_ERR(d); 2093 2094 /* Callers don't care */ 2095 dput(d); 2096 return 0; 2097 } 2098 EXPORT_SYMBOL_GPL(nfs_instantiate); 2099 2100 /* 2101 * Following a failed create operation, we drop the dentry rather 2102 * than retain a negative dentry. This avoids a problem in the event 2103 * that the operation succeeded on the server, but an error in the 2104 * reply path made it appear to have failed. 2105 */ 2106 int nfs_create(struct user_namespace *mnt_userns, struct inode *dir, 2107 struct dentry *dentry, umode_t mode, bool excl) 2108 { 2109 struct iattr attr; 2110 int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT; 2111 int error; 2112 2113 dfprintk(VFS, "NFS: create(%s/%lu), %pd\n", 2114 dir->i_sb->s_id, dir->i_ino, dentry); 2115 2116 attr.ia_mode = mode; 2117 attr.ia_valid = ATTR_MODE; 2118 2119 trace_nfs_create_enter(dir, dentry, open_flags); 2120 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags); 2121 trace_nfs_create_exit(dir, dentry, open_flags, error); 2122 if (error != 0) 2123 goto out_err; 2124 return 0; 2125 out_err: 2126 d_drop(dentry); 2127 return error; 2128 } 2129 EXPORT_SYMBOL_GPL(nfs_create); 2130 2131 /* 2132 * See comments for nfs_proc_create regarding failed operations. 2133 */ 2134 int 2135 nfs_mknod(struct user_namespace *mnt_userns, struct inode *dir, 2136 struct dentry *dentry, umode_t mode, dev_t rdev) 2137 { 2138 struct iattr attr; 2139 int status; 2140 2141 dfprintk(VFS, "NFS: mknod(%s/%lu), %pd\n", 2142 dir->i_sb->s_id, dir->i_ino, dentry); 2143 2144 attr.ia_mode = mode; 2145 attr.ia_valid = ATTR_MODE; 2146 2147 trace_nfs_mknod_enter(dir, dentry); 2148 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); 2149 trace_nfs_mknod_exit(dir, dentry, status); 2150 if (status != 0) 2151 goto out_err; 2152 return 0; 2153 out_err: 2154 d_drop(dentry); 2155 return status; 2156 } 2157 EXPORT_SYMBOL_GPL(nfs_mknod); 2158 2159 /* 2160 * See comments for nfs_proc_create regarding failed operations. 2161 */ 2162 int nfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, 2163 struct dentry *dentry, umode_t mode) 2164 { 2165 struct iattr attr; 2166 int error; 2167 2168 dfprintk(VFS, "NFS: mkdir(%s/%lu), %pd\n", 2169 dir->i_sb->s_id, dir->i_ino, dentry); 2170 2171 attr.ia_valid = ATTR_MODE; 2172 attr.ia_mode = mode | S_IFDIR; 2173 2174 trace_nfs_mkdir_enter(dir, dentry); 2175 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); 2176 trace_nfs_mkdir_exit(dir, dentry, error); 2177 if (error != 0) 2178 goto out_err; 2179 return 0; 2180 out_err: 2181 d_drop(dentry); 2182 return error; 2183 } 2184 EXPORT_SYMBOL_GPL(nfs_mkdir); 2185 2186 static void nfs_dentry_handle_enoent(struct dentry *dentry) 2187 { 2188 if (simple_positive(dentry)) 2189 d_delete(dentry); 2190 } 2191 2192 int nfs_rmdir(struct inode *dir, struct dentry *dentry) 2193 { 2194 int error; 2195 2196 dfprintk(VFS, "NFS: rmdir(%s/%lu), %pd\n", 2197 dir->i_sb->s_id, dir->i_ino, dentry); 2198 2199 trace_nfs_rmdir_enter(dir, dentry); 2200 if (d_really_is_positive(dentry)) { 2201 down_write(&NFS_I(d_inode(dentry))->rmdir_sem); 2202 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 2203 /* Ensure the VFS deletes this inode */ 2204 switch (error) { 2205 case 0: 2206 clear_nlink(d_inode(dentry)); 2207 break; 2208 case -ENOENT: 2209 nfs_dentry_handle_enoent(dentry); 2210 } 2211 up_write(&NFS_I(d_inode(dentry))->rmdir_sem); 2212 } else 2213 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 2214 trace_nfs_rmdir_exit(dir, dentry, error); 2215 2216 return error; 2217 } 2218 EXPORT_SYMBOL_GPL(nfs_rmdir); 2219 2220 /* 2221 * Remove a file after making sure there are no pending writes, 2222 * and after checking that the file has only one user. 2223 * 2224 * We invalidate the attribute cache and free the inode prior to the operation 2225 * to avoid possible races if the server reuses the inode. 2226 */ 2227 static int nfs_safe_remove(struct dentry *dentry) 2228 { 2229 struct inode *dir = d_inode(dentry->d_parent); 2230 struct inode *inode = d_inode(dentry); 2231 int error = -EBUSY; 2232 2233 dfprintk(VFS, "NFS: safe_remove(%pd2)\n", dentry); 2234 2235 /* If the dentry was sillyrenamed, we simply call d_delete() */ 2236 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 2237 error = 0; 2238 goto out; 2239 } 2240 2241 trace_nfs_remove_enter(dir, dentry); 2242 if (inode != NULL) { 2243 error = NFS_PROTO(dir)->remove(dir, dentry); 2244 if (error == 0) 2245 nfs_drop_nlink(inode); 2246 } else 2247 error = NFS_PROTO(dir)->remove(dir, dentry); 2248 if (error == -ENOENT) 2249 nfs_dentry_handle_enoent(dentry); 2250 trace_nfs_remove_exit(dir, dentry, error); 2251 out: 2252 return error; 2253 } 2254 2255 /* We do silly rename. In case sillyrename() returns -EBUSY, the inode 2256 * belongs to an active ".nfs..." file and we return -EBUSY. 2257 * 2258 * If sillyrename() returns 0, we do nothing, otherwise we unlink. 2259 */ 2260 int nfs_unlink(struct inode *dir, struct dentry *dentry) 2261 { 2262 int error; 2263 int need_rehash = 0; 2264 2265 dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id, 2266 dir->i_ino, dentry); 2267 2268 trace_nfs_unlink_enter(dir, dentry); 2269 spin_lock(&dentry->d_lock); 2270 if (d_count(dentry) > 1) { 2271 spin_unlock(&dentry->d_lock); 2272 /* Start asynchronous writeout of the inode */ 2273 write_inode_now(d_inode(dentry), 0); 2274 error = nfs_sillyrename(dir, dentry); 2275 goto out; 2276 } 2277 if (!d_unhashed(dentry)) { 2278 __d_drop(dentry); 2279 need_rehash = 1; 2280 } 2281 spin_unlock(&dentry->d_lock); 2282 error = nfs_safe_remove(dentry); 2283 if (!error || error == -ENOENT) { 2284 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 2285 } else if (need_rehash) 2286 d_rehash(dentry); 2287 out: 2288 trace_nfs_unlink_exit(dir, dentry, error); 2289 return error; 2290 } 2291 EXPORT_SYMBOL_GPL(nfs_unlink); 2292 2293 /* 2294 * To create a symbolic link, most file systems instantiate a new inode, 2295 * add a page to it containing the path, then write it out to the disk 2296 * using prepare_write/commit_write. 2297 * 2298 * Unfortunately the NFS client can't create the in-core inode first 2299 * because it needs a file handle to create an in-core inode (see 2300 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the 2301 * symlink request has completed on the server. 2302 * 2303 * So instead we allocate a raw page, copy the symname into it, then do 2304 * the SYMLINK request with the page as the buffer. If it succeeds, we 2305 * now have a new file handle and can instantiate an in-core NFS inode 2306 * and move the raw page into its mapping. 2307 */ 2308 int nfs_symlink(struct user_namespace *mnt_userns, struct inode *dir, 2309 struct dentry *dentry, const char *symname) 2310 { 2311 struct page *page; 2312 char *kaddr; 2313 struct iattr attr; 2314 unsigned int pathlen = strlen(symname); 2315 int error; 2316 2317 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id, 2318 dir->i_ino, dentry, symname); 2319 2320 if (pathlen > PAGE_SIZE) 2321 return -ENAMETOOLONG; 2322 2323 attr.ia_mode = S_IFLNK | S_IRWXUGO; 2324 attr.ia_valid = ATTR_MODE; 2325 2326 page = alloc_page(GFP_USER); 2327 if (!page) 2328 return -ENOMEM; 2329 2330 kaddr = page_address(page); 2331 memcpy(kaddr, symname, pathlen); 2332 if (pathlen < PAGE_SIZE) 2333 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); 2334 2335 trace_nfs_symlink_enter(dir, dentry); 2336 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr); 2337 trace_nfs_symlink_exit(dir, dentry, error); 2338 if (error != 0) { 2339 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n", 2340 dir->i_sb->s_id, dir->i_ino, 2341 dentry, symname, error); 2342 d_drop(dentry); 2343 __free_page(page); 2344 return error; 2345 } 2346 2347 /* 2348 * No big deal if we can't add this page to the page cache here. 2349 * READLINK will get the missing page from the server if needed. 2350 */ 2351 if (!add_to_page_cache_lru(page, d_inode(dentry)->i_mapping, 0, 2352 GFP_KERNEL)) { 2353 SetPageUptodate(page); 2354 unlock_page(page); 2355 /* 2356 * add_to_page_cache_lru() grabs an extra page refcount. 2357 * Drop it here to avoid leaking this page later. 2358 */ 2359 put_page(page); 2360 } else 2361 __free_page(page); 2362 2363 return 0; 2364 } 2365 EXPORT_SYMBOL_GPL(nfs_symlink); 2366 2367 int 2368 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 2369 { 2370 struct inode *inode = d_inode(old_dentry); 2371 int error; 2372 2373 dfprintk(VFS, "NFS: link(%pd2 -> %pd2)\n", 2374 old_dentry, dentry); 2375 2376 trace_nfs_link_enter(inode, dir, dentry); 2377 d_drop(dentry); 2378 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 2379 if (error == 0) { 2380 ihold(inode); 2381 d_add(dentry, inode); 2382 } 2383 trace_nfs_link_exit(inode, dir, dentry, error); 2384 return error; 2385 } 2386 EXPORT_SYMBOL_GPL(nfs_link); 2387 2388 /* 2389 * RENAME 2390 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a 2391 * different file handle for the same inode after a rename (e.g. when 2392 * moving to a different directory). A fail-safe method to do so would 2393 * be to look up old_dir/old_name, create a link to new_dir/new_name and 2394 * rename the old file using the sillyrename stuff. This way, the original 2395 * file in old_dir will go away when the last process iput()s the inode. 2396 * 2397 * FIXED. 2398 * 2399 * It actually works quite well. One needs to have the possibility for 2400 * at least one ".nfs..." file in each directory the file ever gets 2401 * moved or linked to which happens automagically with the new 2402 * implementation that only depends on the dcache stuff instead of 2403 * using the inode layer 2404 * 2405 * Unfortunately, things are a little more complicated than indicated 2406 * above. For a cross-directory move, we want to make sure we can get 2407 * rid of the old inode after the operation. This means there must be 2408 * no pending writes (if it's a file), and the use count must be 1. 2409 * If these conditions are met, we can drop the dentries before doing 2410 * the rename. 2411 */ 2412 int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir, 2413 struct dentry *old_dentry, struct inode *new_dir, 2414 struct dentry *new_dentry, unsigned int flags) 2415 { 2416 struct inode *old_inode = d_inode(old_dentry); 2417 struct inode *new_inode = d_inode(new_dentry); 2418 struct dentry *dentry = NULL, *rehash = NULL; 2419 struct rpc_task *task; 2420 int error = -EBUSY; 2421 2422 if (flags) 2423 return -EINVAL; 2424 2425 dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n", 2426 old_dentry, new_dentry, 2427 d_count(new_dentry)); 2428 2429 trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry); 2430 /* 2431 * For non-directories, check whether the target is busy and if so, 2432 * make a copy of the dentry and then do a silly-rename. If the 2433 * silly-rename succeeds, the copied dentry is hashed and becomes 2434 * the new target. 2435 */ 2436 if (new_inode && !S_ISDIR(new_inode->i_mode)) { 2437 /* 2438 * To prevent any new references to the target during the 2439 * rename, we unhash the dentry in advance. 2440 */ 2441 if (!d_unhashed(new_dentry)) { 2442 d_drop(new_dentry); 2443 rehash = new_dentry; 2444 } 2445 2446 if (d_count(new_dentry) > 2) { 2447 int err; 2448 2449 /* copy the target dentry's name */ 2450 dentry = d_alloc(new_dentry->d_parent, 2451 &new_dentry->d_name); 2452 if (!dentry) 2453 goto out; 2454 2455 /* silly-rename the existing target ... */ 2456 err = nfs_sillyrename(new_dir, new_dentry); 2457 if (err) 2458 goto out; 2459 2460 new_dentry = dentry; 2461 rehash = NULL; 2462 new_inode = NULL; 2463 } 2464 } 2465 2466 task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL); 2467 if (IS_ERR(task)) { 2468 error = PTR_ERR(task); 2469 goto out; 2470 } 2471 2472 error = rpc_wait_for_completion_task(task); 2473 if (error != 0) { 2474 ((struct nfs_renamedata *)task->tk_calldata)->cancelled = 1; 2475 /* Paired with the atomic_dec_and_test() barrier in rpc_do_put_task() */ 2476 smp_wmb(); 2477 } else 2478 error = task->tk_status; 2479 rpc_put_task(task); 2480 /* Ensure the inode attributes are revalidated */ 2481 if (error == 0) { 2482 spin_lock(&old_inode->i_lock); 2483 NFS_I(old_inode)->attr_gencount = nfs_inc_attr_generation_counter(); 2484 NFS_I(old_inode)->cache_validity |= NFS_INO_INVALID_CHANGE 2485 | NFS_INO_INVALID_CTIME 2486 | NFS_INO_REVAL_FORCED; 2487 spin_unlock(&old_inode->i_lock); 2488 } 2489 out: 2490 if (rehash) 2491 d_rehash(rehash); 2492 trace_nfs_rename_exit(old_dir, old_dentry, 2493 new_dir, new_dentry, error); 2494 if (!error) { 2495 if (new_inode != NULL) 2496 nfs_drop_nlink(new_inode); 2497 /* 2498 * The d_move() should be here instead of in an async RPC completion 2499 * handler because we need the proper locks to move the dentry. If 2500 * we're interrupted by a signal, the async RPC completion handler 2501 * should mark the directories for revalidation. 2502 */ 2503 d_move(old_dentry, new_dentry); 2504 nfs_set_verifier(old_dentry, 2505 nfs_save_change_attribute(new_dir)); 2506 } else if (error == -ENOENT) 2507 nfs_dentry_handle_enoent(old_dentry); 2508 2509 /* new dentry created? */ 2510 if (dentry) 2511 dput(dentry); 2512 return error; 2513 } 2514 EXPORT_SYMBOL_GPL(nfs_rename); 2515 2516 static DEFINE_SPINLOCK(nfs_access_lru_lock); 2517 static LIST_HEAD(nfs_access_lru_list); 2518 static atomic_long_t nfs_access_nr_entries; 2519 2520 static unsigned long nfs_access_max_cachesize = 4*1024*1024; 2521 module_param(nfs_access_max_cachesize, ulong, 0644); 2522 MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length"); 2523 2524 static void nfs_access_free_entry(struct nfs_access_entry *entry) 2525 { 2526 put_cred(entry->cred); 2527 kfree_rcu(entry, rcu_head); 2528 smp_mb__before_atomic(); 2529 atomic_long_dec(&nfs_access_nr_entries); 2530 smp_mb__after_atomic(); 2531 } 2532 2533 static void nfs_access_free_list(struct list_head *head) 2534 { 2535 struct nfs_access_entry *cache; 2536 2537 while (!list_empty(head)) { 2538 cache = list_entry(head->next, struct nfs_access_entry, lru); 2539 list_del(&cache->lru); 2540 nfs_access_free_entry(cache); 2541 } 2542 } 2543 2544 static unsigned long 2545 nfs_do_access_cache_scan(unsigned int nr_to_scan) 2546 { 2547 LIST_HEAD(head); 2548 struct nfs_inode *nfsi, *next; 2549 struct nfs_access_entry *cache; 2550 long freed = 0; 2551 2552 spin_lock(&nfs_access_lru_lock); 2553 list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) { 2554 struct inode *inode; 2555 2556 if (nr_to_scan-- == 0) 2557 break; 2558 inode = &nfsi->vfs_inode; 2559 spin_lock(&inode->i_lock); 2560 if (list_empty(&nfsi->access_cache_entry_lru)) 2561 goto remove_lru_entry; 2562 cache = list_entry(nfsi->access_cache_entry_lru.next, 2563 struct nfs_access_entry, lru); 2564 list_move(&cache->lru, &head); 2565 rb_erase(&cache->rb_node, &nfsi->access_cache); 2566 freed++; 2567 if (!list_empty(&nfsi->access_cache_entry_lru)) 2568 list_move_tail(&nfsi->access_cache_inode_lru, 2569 &nfs_access_lru_list); 2570 else { 2571 remove_lru_entry: 2572 list_del_init(&nfsi->access_cache_inode_lru); 2573 smp_mb__before_atomic(); 2574 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); 2575 smp_mb__after_atomic(); 2576 } 2577 spin_unlock(&inode->i_lock); 2578 } 2579 spin_unlock(&nfs_access_lru_lock); 2580 nfs_access_free_list(&head); 2581 return freed; 2582 } 2583 2584 unsigned long 2585 nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc) 2586 { 2587 int nr_to_scan = sc->nr_to_scan; 2588 gfp_t gfp_mask = sc->gfp_mask; 2589 2590 if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL) 2591 return SHRINK_STOP; 2592 return nfs_do_access_cache_scan(nr_to_scan); 2593 } 2594 2595 2596 unsigned long 2597 nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc) 2598 { 2599 return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries)); 2600 } 2601 2602 static void 2603 nfs_access_cache_enforce_limit(void) 2604 { 2605 long nr_entries = atomic_long_read(&nfs_access_nr_entries); 2606 unsigned long diff; 2607 unsigned int nr_to_scan; 2608 2609 if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize) 2610 return; 2611 nr_to_scan = 100; 2612 diff = nr_entries - nfs_access_max_cachesize; 2613 if (diff < nr_to_scan) 2614 nr_to_scan = diff; 2615 nfs_do_access_cache_scan(nr_to_scan); 2616 } 2617 2618 static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head) 2619 { 2620 struct rb_root *root_node = &nfsi->access_cache; 2621 struct rb_node *n; 2622 struct nfs_access_entry *entry; 2623 2624 /* Unhook entries from the cache */ 2625 while ((n = rb_first(root_node)) != NULL) { 2626 entry = rb_entry(n, struct nfs_access_entry, rb_node); 2627 rb_erase(n, root_node); 2628 list_move(&entry->lru, head); 2629 } 2630 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; 2631 } 2632 2633 void nfs_access_zap_cache(struct inode *inode) 2634 { 2635 LIST_HEAD(head); 2636 2637 if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0) 2638 return; 2639 /* Remove from global LRU init */ 2640 spin_lock(&nfs_access_lru_lock); 2641 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2642 list_del_init(&NFS_I(inode)->access_cache_inode_lru); 2643 2644 spin_lock(&inode->i_lock); 2645 __nfs_access_zap_cache(NFS_I(inode), &head); 2646 spin_unlock(&inode->i_lock); 2647 spin_unlock(&nfs_access_lru_lock); 2648 nfs_access_free_list(&head); 2649 } 2650 EXPORT_SYMBOL_GPL(nfs_access_zap_cache); 2651 2652 static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, const struct cred *cred) 2653 { 2654 struct rb_node *n = NFS_I(inode)->access_cache.rb_node; 2655 2656 while (n != NULL) { 2657 struct nfs_access_entry *entry = 2658 rb_entry(n, struct nfs_access_entry, rb_node); 2659 int cmp = cred_fscmp(cred, entry->cred); 2660 2661 if (cmp < 0) 2662 n = n->rb_left; 2663 else if (cmp > 0) 2664 n = n->rb_right; 2665 else 2666 return entry; 2667 } 2668 return NULL; 2669 } 2670 2671 static int nfs_access_get_cached_locked(struct inode *inode, const struct cred *cred, struct nfs_access_entry *res, bool may_block) 2672 { 2673 struct nfs_inode *nfsi = NFS_I(inode); 2674 struct nfs_access_entry *cache; 2675 bool retry = true; 2676 int err; 2677 2678 spin_lock(&inode->i_lock); 2679 for(;;) { 2680 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2681 goto out_zap; 2682 cache = nfs_access_search_rbtree(inode, cred); 2683 err = -ENOENT; 2684 if (cache == NULL) 2685 goto out; 2686 /* Found an entry, is our attribute cache valid? */ 2687 if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) 2688 break; 2689 if (!retry) 2690 break; 2691 err = -ECHILD; 2692 if (!may_block) 2693 goto out; 2694 spin_unlock(&inode->i_lock); 2695 err = __nfs_revalidate_inode(NFS_SERVER(inode), inode); 2696 if (err) 2697 return err; 2698 spin_lock(&inode->i_lock); 2699 retry = false; 2700 } 2701 res->cred = cache->cred; 2702 res->mask = cache->mask; 2703 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru); 2704 err = 0; 2705 out: 2706 spin_unlock(&inode->i_lock); 2707 return err; 2708 out_zap: 2709 spin_unlock(&inode->i_lock); 2710 nfs_access_zap_cache(inode); 2711 return -ENOENT; 2712 } 2713 2714 static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cred, struct nfs_access_entry *res) 2715 { 2716 /* Only check the most recently returned cache entry, 2717 * but do it without locking. 2718 */ 2719 struct nfs_inode *nfsi = NFS_I(inode); 2720 struct nfs_access_entry *cache; 2721 int err = -ECHILD; 2722 struct list_head *lh; 2723 2724 rcu_read_lock(); 2725 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2726 goto out; 2727 lh = rcu_dereference(list_tail_rcu(&nfsi->access_cache_entry_lru)); 2728 cache = list_entry(lh, struct nfs_access_entry, lru); 2729 if (lh == &nfsi->access_cache_entry_lru || 2730 cred_fscmp(cred, cache->cred) != 0) 2731 cache = NULL; 2732 if (cache == NULL) 2733 goto out; 2734 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) 2735 goto out; 2736 res->cred = cache->cred; 2737 res->mask = cache->mask; 2738 err = 0; 2739 out: 2740 rcu_read_unlock(); 2741 return err; 2742 } 2743 2744 int nfs_access_get_cached(struct inode *inode, const struct cred *cred, struct 2745 nfs_access_entry *res, bool may_block) 2746 { 2747 int status; 2748 2749 status = nfs_access_get_cached_rcu(inode, cred, res); 2750 if (status != 0) 2751 status = nfs_access_get_cached_locked(inode, cred, res, 2752 may_block); 2753 2754 return status; 2755 } 2756 EXPORT_SYMBOL_GPL(nfs_access_get_cached); 2757 2758 static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) 2759 { 2760 struct nfs_inode *nfsi = NFS_I(inode); 2761 struct rb_root *root_node = &nfsi->access_cache; 2762 struct rb_node **p = &root_node->rb_node; 2763 struct rb_node *parent = NULL; 2764 struct nfs_access_entry *entry; 2765 int cmp; 2766 2767 spin_lock(&inode->i_lock); 2768 while (*p != NULL) { 2769 parent = *p; 2770 entry = rb_entry(parent, struct nfs_access_entry, rb_node); 2771 cmp = cred_fscmp(set->cred, entry->cred); 2772 2773 if (cmp < 0) 2774 p = &parent->rb_left; 2775 else if (cmp > 0) 2776 p = &parent->rb_right; 2777 else 2778 goto found; 2779 } 2780 rb_link_node(&set->rb_node, parent, p); 2781 rb_insert_color(&set->rb_node, root_node); 2782 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 2783 spin_unlock(&inode->i_lock); 2784 return; 2785 found: 2786 rb_replace_node(parent, &set->rb_node, root_node); 2787 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 2788 list_del(&entry->lru); 2789 spin_unlock(&inode->i_lock); 2790 nfs_access_free_entry(entry); 2791 } 2792 2793 void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) 2794 { 2795 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); 2796 if (cache == NULL) 2797 return; 2798 RB_CLEAR_NODE(&cache->rb_node); 2799 cache->cred = get_cred(set->cred); 2800 cache->mask = set->mask; 2801 2802 /* The above field assignments must be visible 2803 * before this item appears on the lru. We cannot easily 2804 * use rcu_assign_pointer, so just force the memory barrier. 2805 */ 2806 smp_wmb(); 2807 nfs_access_add_rbtree(inode, cache); 2808 2809 /* Update accounting */ 2810 smp_mb__before_atomic(); 2811 atomic_long_inc(&nfs_access_nr_entries); 2812 smp_mb__after_atomic(); 2813 2814 /* Add inode to global LRU list */ 2815 if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) { 2816 spin_lock(&nfs_access_lru_lock); 2817 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2818 list_add_tail(&NFS_I(inode)->access_cache_inode_lru, 2819 &nfs_access_lru_list); 2820 spin_unlock(&nfs_access_lru_lock); 2821 } 2822 nfs_access_cache_enforce_limit(); 2823 } 2824 EXPORT_SYMBOL_GPL(nfs_access_add_cache); 2825 2826 #define NFS_MAY_READ (NFS_ACCESS_READ) 2827 #define NFS_MAY_WRITE (NFS_ACCESS_MODIFY | \ 2828 NFS_ACCESS_EXTEND | \ 2829 NFS_ACCESS_DELETE) 2830 #define NFS_FILE_MAY_WRITE (NFS_ACCESS_MODIFY | \ 2831 NFS_ACCESS_EXTEND) 2832 #define NFS_DIR_MAY_WRITE NFS_MAY_WRITE 2833 #define NFS_MAY_LOOKUP (NFS_ACCESS_LOOKUP) 2834 #define NFS_MAY_EXECUTE (NFS_ACCESS_EXECUTE) 2835 static int 2836 nfs_access_calc_mask(u32 access_result, umode_t umode) 2837 { 2838 int mask = 0; 2839 2840 if (access_result & NFS_MAY_READ) 2841 mask |= MAY_READ; 2842 if (S_ISDIR(umode)) { 2843 if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE) 2844 mask |= MAY_WRITE; 2845 if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP) 2846 mask |= MAY_EXEC; 2847 } else if (S_ISREG(umode)) { 2848 if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE) 2849 mask |= MAY_WRITE; 2850 if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE) 2851 mask |= MAY_EXEC; 2852 } else if (access_result & NFS_MAY_WRITE) 2853 mask |= MAY_WRITE; 2854 return mask; 2855 } 2856 2857 void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result) 2858 { 2859 entry->mask = access_result; 2860 } 2861 EXPORT_SYMBOL_GPL(nfs_access_set_mask); 2862 2863 static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask) 2864 { 2865 struct nfs_access_entry cache; 2866 bool may_block = (mask & MAY_NOT_BLOCK) == 0; 2867 int cache_mask = -1; 2868 int status; 2869 2870 trace_nfs_access_enter(inode); 2871 2872 status = nfs_access_get_cached(inode, cred, &cache, may_block); 2873 if (status == 0) 2874 goto out_cached; 2875 2876 status = -ECHILD; 2877 if (!may_block) 2878 goto out; 2879 2880 /* 2881 * Determine which access bits we want to ask for... 2882 */ 2883 cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND; 2884 if (nfs_server_capable(inode, NFS_CAP_XATTR)) { 2885 cache.mask |= NFS_ACCESS_XAREAD | NFS_ACCESS_XAWRITE | 2886 NFS_ACCESS_XALIST; 2887 } 2888 if (S_ISDIR(inode->i_mode)) 2889 cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP; 2890 else 2891 cache.mask |= NFS_ACCESS_EXECUTE; 2892 cache.cred = cred; 2893 status = NFS_PROTO(inode)->access(inode, &cache); 2894 if (status != 0) { 2895 if (status == -ESTALE) { 2896 if (!S_ISDIR(inode->i_mode)) 2897 nfs_set_inode_stale(inode); 2898 else 2899 nfs_zap_caches(inode); 2900 } 2901 goto out; 2902 } 2903 nfs_access_add_cache(inode, &cache); 2904 out_cached: 2905 cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode); 2906 if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0) 2907 status = -EACCES; 2908 out: 2909 trace_nfs_access_exit(inode, mask, cache_mask, status); 2910 return status; 2911 } 2912 2913 static int nfs_open_permission_mask(int openflags) 2914 { 2915 int mask = 0; 2916 2917 if (openflags & __FMODE_EXEC) { 2918 /* ONLY check exec rights */ 2919 mask = MAY_EXEC; 2920 } else { 2921 if ((openflags & O_ACCMODE) != O_WRONLY) 2922 mask |= MAY_READ; 2923 if ((openflags & O_ACCMODE) != O_RDONLY) 2924 mask |= MAY_WRITE; 2925 } 2926 2927 return mask; 2928 } 2929 2930 int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags) 2931 { 2932 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); 2933 } 2934 EXPORT_SYMBOL_GPL(nfs_may_open); 2935 2936 static int nfs_execute_ok(struct inode *inode, int mask) 2937 { 2938 struct nfs_server *server = NFS_SERVER(inode); 2939 int ret = 0; 2940 2941 if (S_ISDIR(inode->i_mode)) 2942 return 0; 2943 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_OTHER)) { 2944 if (mask & MAY_NOT_BLOCK) 2945 return -ECHILD; 2946 ret = __nfs_revalidate_inode(server, inode); 2947 } 2948 if (ret == 0 && !execute_ok(inode)) 2949 ret = -EACCES; 2950 return ret; 2951 } 2952 2953 int nfs_permission(struct user_namespace *mnt_userns, 2954 struct inode *inode, 2955 int mask) 2956 { 2957 const struct cred *cred = current_cred(); 2958 int res = 0; 2959 2960 nfs_inc_stats(inode, NFSIOS_VFSACCESS); 2961 2962 if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) 2963 goto out; 2964 /* Is this sys_access() ? */ 2965 if (mask & (MAY_ACCESS | MAY_CHDIR)) 2966 goto force_lookup; 2967 2968 switch (inode->i_mode & S_IFMT) { 2969 case S_IFLNK: 2970 goto out; 2971 case S_IFREG: 2972 if ((mask & MAY_OPEN) && 2973 nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)) 2974 return 0; 2975 break; 2976 case S_IFDIR: 2977 /* 2978 * Optimize away all write operations, since the server 2979 * will check permissions when we perform the op. 2980 */ 2981 if ((mask & MAY_WRITE) && !(mask & MAY_READ)) 2982 goto out; 2983 } 2984 2985 force_lookup: 2986 if (!NFS_PROTO(inode)->access) 2987 goto out_notsup; 2988 2989 res = nfs_do_access(inode, cred, mask); 2990 out: 2991 if (!res && (mask & MAY_EXEC)) 2992 res = nfs_execute_ok(inode, mask); 2993 2994 dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n", 2995 inode->i_sb->s_id, inode->i_ino, mask, res); 2996 return res; 2997 out_notsup: 2998 if (mask & MAY_NOT_BLOCK) 2999 return -ECHILD; 3000 3001 res = nfs_revalidate_inode(NFS_SERVER(inode), inode); 3002 if (res == 0) 3003 res = generic_permission(&init_user_ns, inode, mask); 3004 goto out; 3005 } 3006 EXPORT_SYMBOL_GPL(nfs_permission); 3007 3008 /* 3009 * Local variables: 3010 * version-control: t 3011 * kept-new-versions: 5 3012 * End: 3013 */ 3014