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/compat.h> 22 #include <linux/module.h> 23 #include <linux/time.h> 24 #include <linux/errno.h> 25 #include <linux/stat.h> 26 #include <linux/fcntl.h> 27 #include <linux/string.h> 28 #include <linux/kernel.h> 29 #include <linux/slab.h> 30 #include <linux/mm.h> 31 #include <linux/sunrpc/clnt.h> 32 #include <linux/nfs_fs.h> 33 #include <linux/nfs_mount.h> 34 #include <linux/pagemap.h> 35 #include <linux/pagevec.h> 36 #include <linux/namei.h> 37 #include <linux/mount.h> 38 #include <linux/swap.h> 39 #include <linux/sched.h> 40 #include <linux/kmemleak.h> 41 #include <linux/xattr.h> 42 #include <linux/xxhash.h> 43 44 #include "delegation.h" 45 #include "iostat.h" 46 #include "internal.h" 47 #include "fscache.h" 48 49 #include "nfstrace.h" 50 51 /* #define NFS_DEBUG_VERBOSE 1 */ 52 53 static int nfs_opendir(struct inode *, struct file *); 54 static int nfs_closedir(struct inode *, struct file *); 55 static int nfs_readdir(struct file *, struct dir_context *); 56 static int nfs_fsync_dir(struct file *, loff_t, loff_t, int); 57 static loff_t nfs_llseek_dir(struct file *, loff_t, int); 58 static void nfs_readdir_clear_array(struct page*); 59 60 const struct file_operations nfs_dir_operations = { 61 .llseek = nfs_llseek_dir, 62 .read = generic_read_dir, 63 .iterate_shared = nfs_readdir, 64 .open = nfs_opendir, 65 .release = nfs_closedir, 66 .fsync = nfs_fsync_dir, 67 }; 68 69 const struct address_space_operations nfs_dir_aops = { 70 .freepage = nfs_readdir_clear_array, 71 }; 72 73 #define NFS_INIT_DTSIZE PAGE_SIZE 74 75 static struct nfs_open_dir_context * 76 alloc_nfs_open_dir_context(struct inode *dir) 77 { 78 struct nfs_inode *nfsi = NFS_I(dir); 79 struct nfs_open_dir_context *ctx; 80 81 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT); 82 if (ctx != NULL) { 83 ctx->attr_gencount = nfsi->attr_gencount; 84 ctx->dtsize = NFS_INIT_DTSIZE; 85 spin_lock(&dir->i_lock); 86 if (list_empty(&nfsi->open_files) && 87 (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER)) 88 nfs_set_cache_invalid(dir, 89 NFS_INO_INVALID_DATA | 90 NFS_INO_REVAL_FORCED); 91 list_add_tail_rcu(&ctx->list, &nfsi->open_files); 92 memcpy(ctx->verf, nfsi->cookieverf, sizeof(ctx->verf)); 93 spin_unlock(&dir->i_lock); 94 return ctx; 95 } 96 return ERR_PTR(-ENOMEM); 97 } 98 99 static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx) 100 { 101 spin_lock(&dir->i_lock); 102 list_del_rcu(&ctx->list); 103 spin_unlock(&dir->i_lock); 104 kfree_rcu(ctx, rcu_head); 105 } 106 107 /* 108 * Open file 109 */ 110 static int 111 nfs_opendir(struct inode *inode, struct file *filp) 112 { 113 int res = 0; 114 struct nfs_open_dir_context *ctx; 115 116 dfprintk(FILE, "NFS: open dir(%pD2)\n", filp); 117 118 nfs_inc_stats(inode, NFSIOS_VFSOPEN); 119 120 ctx = alloc_nfs_open_dir_context(inode); 121 if (IS_ERR(ctx)) { 122 res = PTR_ERR(ctx); 123 goto out; 124 } 125 filp->private_data = ctx; 126 out: 127 return res; 128 } 129 130 static int 131 nfs_closedir(struct inode *inode, struct file *filp) 132 { 133 put_nfs_open_dir_context(file_inode(filp), filp->private_data); 134 return 0; 135 } 136 137 struct nfs_cache_array_entry { 138 u64 cookie; 139 u64 ino; 140 const char *name; 141 unsigned int name_len; 142 unsigned char d_type; 143 }; 144 145 struct nfs_cache_array { 146 u64 change_attr; 147 u64 last_cookie; 148 unsigned int size; 149 unsigned char page_full : 1, 150 page_is_eof : 1, 151 cookies_are_ordered : 1; 152 struct nfs_cache_array_entry array[]; 153 }; 154 155 struct nfs_readdir_descriptor { 156 struct file *file; 157 struct page *page; 158 struct dir_context *ctx; 159 pgoff_t page_index; 160 pgoff_t page_index_max; 161 u64 dir_cookie; 162 u64 last_cookie; 163 loff_t current_index; 164 165 __be32 verf[NFS_DIR_VERIFIER_SIZE]; 166 unsigned long dir_verifier; 167 unsigned long timestamp; 168 unsigned long gencount; 169 unsigned long attr_gencount; 170 unsigned int cache_entry_index; 171 unsigned int buffer_fills; 172 unsigned int dtsize; 173 bool clear_cache; 174 bool plus; 175 bool eob; 176 bool eof; 177 }; 178 179 static void nfs_set_dtsize(struct nfs_readdir_descriptor *desc, unsigned int sz) 180 { 181 struct nfs_server *server = NFS_SERVER(file_inode(desc->file)); 182 unsigned int maxsize = server->dtsize; 183 184 if (sz > maxsize) 185 sz = maxsize; 186 if (sz < NFS_MIN_FILE_IO_SIZE) 187 sz = NFS_MIN_FILE_IO_SIZE; 188 desc->dtsize = sz; 189 } 190 191 static void nfs_shrink_dtsize(struct nfs_readdir_descriptor *desc) 192 { 193 nfs_set_dtsize(desc, desc->dtsize >> 1); 194 } 195 196 static void nfs_grow_dtsize(struct nfs_readdir_descriptor *desc) 197 { 198 nfs_set_dtsize(desc, desc->dtsize << 1); 199 } 200 201 static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie, 202 u64 change_attr) 203 { 204 struct nfs_cache_array *array; 205 206 array = kmap_atomic(page); 207 array->change_attr = change_attr; 208 array->last_cookie = last_cookie; 209 array->size = 0; 210 array->page_full = 0; 211 array->page_is_eof = 0; 212 array->cookies_are_ordered = 1; 213 kunmap_atomic(array); 214 } 215 216 /* 217 * we are freeing strings created by nfs_add_to_readdir_array() 218 */ 219 static void nfs_readdir_clear_array(struct page *page) 220 { 221 struct nfs_cache_array *array; 222 unsigned int i; 223 224 array = kmap_atomic(page); 225 for (i = 0; i < array->size; i++) 226 kfree(array->array[i].name); 227 array->size = 0; 228 kunmap_atomic(array); 229 } 230 231 static void nfs_readdir_page_reinit_array(struct page *page, u64 last_cookie, 232 u64 change_attr) 233 { 234 nfs_readdir_clear_array(page); 235 nfs_readdir_page_init_array(page, last_cookie, change_attr); 236 } 237 238 static struct page * 239 nfs_readdir_page_array_alloc(u64 last_cookie, gfp_t gfp_flags) 240 { 241 struct page *page = alloc_page(gfp_flags); 242 if (page) 243 nfs_readdir_page_init_array(page, last_cookie, 0); 244 return page; 245 } 246 247 static void nfs_readdir_page_array_free(struct page *page) 248 { 249 if (page) { 250 nfs_readdir_clear_array(page); 251 put_page(page); 252 } 253 } 254 255 static u64 nfs_readdir_array_index_cookie(struct nfs_cache_array *array) 256 { 257 return array->size == 0 ? array->last_cookie : array->array[0].cookie; 258 } 259 260 static void nfs_readdir_array_set_eof(struct nfs_cache_array *array) 261 { 262 array->page_is_eof = 1; 263 array->page_full = 1; 264 } 265 266 static bool nfs_readdir_array_is_full(struct nfs_cache_array *array) 267 { 268 return array->page_full; 269 } 270 271 /* 272 * the caller is responsible for freeing qstr.name 273 * when called by nfs_readdir_add_to_array, the strings will be freed in 274 * nfs_clear_readdir_array() 275 */ 276 static const char *nfs_readdir_copy_name(const char *name, unsigned int len) 277 { 278 const char *ret = kmemdup_nul(name, len, GFP_KERNEL); 279 280 /* 281 * Avoid a kmemleak false positive. The pointer to the name is stored 282 * in a page cache page which kmemleak does not scan. 283 */ 284 if (ret != NULL) 285 kmemleak_not_leak(ret); 286 return ret; 287 } 288 289 static size_t nfs_readdir_array_maxentries(void) 290 { 291 return (PAGE_SIZE - sizeof(struct nfs_cache_array)) / 292 sizeof(struct nfs_cache_array_entry); 293 } 294 295 /* 296 * Check that the next array entry lies entirely within the page bounds 297 */ 298 static int nfs_readdir_array_can_expand(struct nfs_cache_array *array) 299 { 300 if (array->page_full) 301 return -ENOSPC; 302 if (array->size == nfs_readdir_array_maxentries()) { 303 array->page_full = 1; 304 return -ENOSPC; 305 } 306 return 0; 307 } 308 309 static int nfs_readdir_page_array_append(struct page *page, 310 const struct nfs_entry *entry, 311 u64 *cookie) 312 { 313 struct nfs_cache_array *array; 314 struct nfs_cache_array_entry *cache_entry; 315 const char *name; 316 int ret = -ENOMEM; 317 318 name = nfs_readdir_copy_name(entry->name, entry->len); 319 320 array = kmap_atomic(page); 321 if (!name) 322 goto out; 323 ret = nfs_readdir_array_can_expand(array); 324 if (ret) { 325 kfree(name); 326 goto out; 327 } 328 329 cache_entry = &array->array[array->size]; 330 cache_entry->cookie = array->last_cookie; 331 cache_entry->ino = entry->ino; 332 cache_entry->d_type = entry->d_type; 333 cache_entry->name_len = entry->len; 334 cache_entry->name = name; 335 array->last_cookie = entry->cookie; 336 if (array->last_cookie <= cache_entry->cookie) 337 array->cookies_are_ordered = 0; 338 array->size++; 339 if (entry->eof != 0) 340 nfs_readdir_array_set_eof(array); 341 out: 342 *cookie = array->last_cookie; 343 kunmap_atomic(array); 344 return ret; 345 } 346 347 #define NFS_READDIR_COOKIE_MASK (U32_MAX >> 14) 348 /* 349 * Hash algorithm allowing content addressible access to sequences 350 * of directory cookies. Content is addressed by the value of the 351 * cookie index of the first readdir entry in a page. 352 * 353 * The xxhash algorithm is chosen because it is fast, and is supposed 354 * to result in a decent flat distribution of hashes. 355 * 356 * We then select only the first 18 bits to avoid issues with excessive 357 * memory use for the page cache XArray. 18 bits should allow the caching 358 * of 262144 pages of sequences of readdir entries. Since each page holds 359 * 127 readdir entries for a typical 64-bit system, that works out to a 360 * cache of ~ 33 million entries per directory. 361 */ 362 static pgoff_t nfs_readdir_page_cookie_hash(u64 cookie) 363 { 364 if (cookie == 0) 365 return 0; 366 return xxhash(&cookie, sizeof(cookie), 0) & NFS_READDIR_COOKIE_MASK; 367 } 368 369 static bool nfs_readdir_page_validate(struct page *page, u64 last_cookie, 370 u64 change_attr) 371 { 372 struct nfs_cache_array *array = kmap_atomic(page); 373 int ret = true; 374 375 if (array->change_attr != change_attr) 376 ret = false; 377 if (nfs_readdir_array_index_cookie(array) != last_cookie) 378 ret = false; 379 kunmap_atomic(array); 380 return ret; 381 } 382 383 static void nfs_readdir_page_unlock_and_put(struct page *page) 384 { 385 unlock_page(page); 386 put_page(page); 387 } 388 389 static void nfs_readdir_page_init_and_validate(struct page *page, u64 cookie, 390 u64 change_attr) 391 { 392 if (PageUptodate(page)) { 393 if (nfs_readdir_page_validate(page, cookie, change_attr)) 394 return; 395 nfs_readdir_clear_array(page); 396 } 397 nfs_readdir_page_init_array(page, cookie, change_attr); 398 SetPageUptodate(page); 399 } 400 401 static struct page *nfs_readdir_page_get_locked(struct address_space *mapping, 402 u64 cookie, u64 change_attr) 403 { 404 pgoff_t index = nfs_readdir_page_cookie_hash(cookie); 405 struct page *page; 406 407 page = grab_cache_page(mapping, index); 408 if (!page) 409 return NULL; 410 nfs_readdir_page_init_and_validate(page, cookie, change_attr); 411 return page; 412 } 413 414 static u64 nfs_readdir_page_last_cookie(struct page *page) 415 { 416 struct nfs_cache_array *array; 417 u64 ret; 418 419 array = kmap_atomic(page); 420 ret = array->last_cookie; 421 kunmap_atomic(array); 422 return ret; 423 } 424 425 static bool nfs_readdir_page_needs_filling(struct page *page) 426 { 427 struct nfs_cache_array *array; 428 bool ret; 429 430 array = kmap_atomic(page); 431 ret = !nfs_readdir_array_is_full(array); 432 kunmap_atomic(array); 433 return ret; 434 } 435 436 static void nfs_readdir_page_set_eof(struct page *page) 437 { 438 struct nfs_cache_array *array; 439 440 array = kmap_atomic(page); 441 nfs_readdir_array_set_eof(array); 442 kunmap_atomic(array); 443 } 444 445 static struct page *nfs_readdir_page_get_next(struct address_space *mapping, 446 u64 cookie, u64 change_attr) 447 { 448 pgoff_t index = nfs_readdir_page_cookie_hash(cookie); 449 struct page *page; 450 451 page = grab_cache_page_nowait(mapping, index); 452 if (!page) 453 return NULL; 454 nfs_readdir_page_init_and_validate(page, cookie, change_attr); 455 if (nfs_readdir_page_last_cookie(page) != cookie) 456 nfs_readdir_page_reinit_array(page, cookie, change_attr); 457 return page; 458 } 459 460 static inline 461 int is_32bit_api(void) 462 { 463 #ifdef CONFIG_COMPAT 464 return in_compat_syscall(); 465 #else 466 return (BITS_PER_LONG == 32); 467 #endif 468 } 469 470 static 471 bool nfs_readdir_use_cookie(const struct file *filp) 472 { 473 if ((filp->f_mode & FMODE_32BITHASH) || 474 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api())) 475 return false; 476 return true; 477 } 478 479 static void nfs_readdir_seek_next_array(struct nfs_cache_array *array, 480 struct nfs_readdir_descriptor *desc) 481 { 482 if (array->page_full) { 483 desc->last_cookie = array->last_cookie; 484 desc->current_index += array->size; 485 desc->cache_entry_index = 0; 486 desc->page_index++; 487 } else 488 desc->last_cookie = nfs_readdir_array_index_cookie(array); 489 } 490 491 static void nfs_readdir_rewind_search(struct nfs_readdir_descriptor *desc) 492 { 493 desc->current_index = 0; 494 desc->last_cookie = 0; 495 desc->page_index = 0; 496 } 497 498 static int nfs_readdir_search_for_pos(struct nfs_cache_array *array, 499 struct nfs_readdir_descriptor *desc) 500 { 501 loff_t diff = desc->ctx->pos - desc->current_index; 502 unsigned int index; 503 504 if (diff < 0) 505 goto out_eof; 506 if (diff >= array->size) { 507 if (array->page_is_eof) 508 goto out_eof; 509 nfs_readdir_seek_next_array(array, desc); 510 return -EAGAIN; 511 } 512 513 index = (unsigned int)diff; 514 desc->dir_cookie = array->array[index].cookie; 515 desc->cache_entry_index = index; 516 return 0; 517 out_eof: 518 desc->eof = true; 519 return -EBADCOOKIE; 520 } 521 522 static bool nfs_readdir_array_cookie_in_range(struct nfs_cache_array *array, 523 u64 cookie) 524 { 525 if (!array->cookies_are_ordered) 526 return true; 527 /* Optimisation for monotonically increasing cookies */ 528 if (cookie >= array->last_cookie) 529 return false; 530 if (array->size && cookie < array->array[0].cookie) 531 return false; 532 return true; 533 } 534 535 static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, 536 struct nfs_readdir_descriptor *desc) 537 { 538 unsigned int i; 539 int status = -EAGAIN; 540 541 if (!nfs_readdir_array_cookie_in_range(array, desc->dir_cookie)) 542 goto check_eof; 543 544 for (i = 0; i < array->size; i++) { 545 if (array->array[i].cookie == desc->dir_cookie) { 546 if (nfs_readdir_use_cookie(desc->file)) 547 desc->ctx->pos = desc->dir_cookie; 548 else 549 desc->ctx->pos = desc->current_index + i; 550 desc->cache_entry_index = i; 551 return 0; 552 } 553 } 554 check_eof: 555 if (array->page_is_eof) { 556 status = -EBADCOOKIE; 557 if (desc->dir_cookie == array->last_cookie) 558 desc->eof = true; 559 } else 560 nfs_readdir_seek_next_array(array, desc); 561 return status; 562 } 563 564 static int nfs_readdir_search_array(struct nfs_readdir_descriptor *desc) 565 { 566 struct nfs_cache_array *array; 567 int status; 568 569 array = kmap_atomic(desc->page); 570 571 if (desc->dir_cookie == 0) 572 status = nfs_readdir_search_for_pos(array, desc); 573 else 574 status = nfs_readdir_search_for_cookie(array, desc); 575 576 kunmap_atomic(array); 577 return status; 578 } 579 580 /* Fill a page with xdr information before transferring to the cache page */ 581 static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc, 582 __be32 *verf, u64 cookie, 583 struct page **pages, size_t bufsize, 584 __be32 *verf_res) 585 { 586 struct inode *inode = file_inode(desc->file); 587 struct nfs_readdir_arg arg = { 588 .dentry = file_dentry(desc->file), 589 .cred = desc->file->f_cred, 590 .verf = verf, 591 .cookie = cookie, 592 .pages = pages, 593 .page_len = bufsize, 594 .plus = desc->plus, 595 }; 596 struct nfs_readdir_res res = { 597 .verf = verf_res, 598 }; 599 unsigned long timestamp, gencount; 600 int error; 601 602 again: 603 timestamp = jiffies; 604 gencount = nfs_inc_attr_generation_counter(); 605 desc->dir_verifier = nfs_save_change_attribute(inode); 606 error = NFS_PROTO(inode)->readdir(&arg, &res); 607 if (error < 0) { 608 /* We requested READDIRPLUS, but the server doesn't grok it */ 609 if (error == -ENOTSUPP && desc->plus) { 610 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; 611 desc->plus = arg.plus = false; 612 goto again; 613 } 614 goto error; 615 } 616 desc->timestamp = timestamp; 617 desc->gencount = gencount; 618 error: 619 return error; 620 } 621 622 static int xdr_decode(struct nfs_readdir_descriptor *desc, 623 struct nfs_entry *entry, struct xdr_stream *xdr) 624 { 625 struct inode *inode = file_inode(desc->file); 626 int error; 627 628 error = NFS_PROTO(inode)->decode_dirent(xdr, entry, desc->plus); 629 if (error) 630 return error; 631 entry->fattr->time_start = desc->timestamp; 632 entry->fattr->gencount = desc->gencount; 633 return 0; 634 } 635 636 /* Match file and dirent using either filehandle or fileid 637 * Note: caller is responsible for checking the fsid 638 */ 639 static 640 int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) 641 { 642 struct inode *inode; 643 struct nfs_inode *nfsi; 644 645 if (d_really_is_negative(dentry)) 646 return 0; 647 648 inode = d_inode(dentry); 649 if (is_bad_inode(inode) || NFS_STALE(inode)) 650 return 0; 651 652 nfsi = NFS_I(inode); 653 if (entry->fattr->fileid != nfsi->fileid) 654 return 0; 655 if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0) 656 return 0; 657 return 1; 658 } 659 660 #define NFS_READDIR_CACHE_USAGE_THRESHOLD (8UL) 661 662 static bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx, 663 unsigned int cache_hits, 664 unsigned int cache_misses) 665 { 666 if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS)) 667 return false; 668 if (ctx->pos == 0 || 669 cache_hits + cache_misses > NFS_READDIR_CACHE_USAGE_THRESHOLD) 670 return true; 671 return false; 672 } 673 674 /* 675 * This function is called by the getattr code to request the 676 * use of readdirplus to accelerate any future lookups in the same 677 * directory. 678 */ 679 void nfs_readdir_record_entry_cache_hit(struct inode *dir) 680 { 681 struct nfs_inode *nfsi = NFS_I(dir); 682 struct nfs_open_dir_context *ctx; 683 684 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && 685 S_ISDIR(dir->i_mode)) { 686 rcu_read_lock(); 687 list_for_each_entry_rcu (ctx, &nfsi->open_files, list) 688 atomic_inc(&ctx->cache_hits); 689 rcu_read_unlock(); 690 } 691 } 692 693 /* 694 * This function is mainly for use by nfs_getattr(). 695 * 696 * If this is an 'ls -l', we want to force use of readdirplus. 697 */ 698 void nfs_readdir_record_entry_cache_miss(struct inode *dir) 699 { 700 struct nfs_inode *nfsi = NFS_I(dir); 701 struct nfs_open_dir_context *ctx; 702 703 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && 704 S_ISDIR(dir->i_mode)) { 705 rcu_read_lock(); 706 list_for_each_entry_rcu (ctx, &nfsi->open_files, list) 707 atomic_inc(&ctx->cache_misses); 708 rcu_read_unlock(); 709 } 710 } 711 712 static void nfs_lookup_advise_force_readdirplus(struct inode *dir, 713 unsigned int flags) 714 { 715 if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) 716 return; 717 if (flags & (LOOKUP_EXCL | LOOKUP_PARENT | LOOKUP_REVAL)) 718 return; 719 nfs_readdir_record_entry_cache_miss(dir); 720 } 721 722 static 723 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry, 724 unsigned long dir_verifier) 725 { 726 struct qstr filename = QSTR_INIT(entry->name, entry->len); 727 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 728 struct dentry *dentry; 729 struct dentry *alias; 730 struct inode *inode; 731 int status; 732 733 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID)) 734 return; 735 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID)) 736 return; 737 if (filename.len == 0) 738 return; 739 /* Validate that the name doesn't contain any illegal '\0' */ 740 if (strnlen(filename.name, filename.len) != filename.len) 741 return; 742 /* ...or '/' */ 743 if (strnchr(filename.name, filename.len, '/')) 744 return; 745 if (filename.name[0] == '.') { 746 if (filename.len == 1) 747 return; 748 if (filename.len == 2 && filename.name[1] == '.') 749 return; 750 } 751 filename.hash = full_name_hash(parent, filename.name, filename.len); 752 753 dentry = d_lookup(parent, &filename); 754 again: 755 if (!dentry) { 756 dentry = d_alloc_parallel(parent, &filename, &wq); 757 if (IS_ERR(dentry)) 758 return; 759 } 760 if (!d_in_lookup(dentry)) { 761 /* Is there a mountpoint here? If so, just exit */ 762 if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid, 763 &entry->fattr->fsid)) 764 goto out; 765 if (nfs_same_file(dentry, entry)) { 766 if (!entry->fh->size) 767 goto out; 768 nfs_set_verifier(dentry, dir_verifier); 769 status = nfs_refresh_inode(d_inode(dentry), entry->fattr); 770 if (!status) 771 nfs_setsecurity(d_inode(dentry), entry->fattr); 772 trace_nfs_readdir_lookup_revalidate(d_inode(parent), 773 dentry, 0, status); 774 goto out; 775 } else { 776 trace_nfs_readdir_lookup_revalidate_failed( 777 d_inode(parent), dentry, 0); 778 d_invalidate(dentry); 779 dput(dentry); 780 dentry = NULL; 781 goto again; 782 } 783 } 784 if (!entry->fh->size) { 785 d_lookup_done(dentry); 786 goto out; 787 } 788 789 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); 790 alias = d_splice_alias(inode, dentry); 791 d_lookup_done(dentry); 792 if (alias) { 793 if (IS_ERR(alias)) 794 goto out; 795 dput(dentry); 796 dentry = alias; 797 } 798 nfs_set_verifier(dentry, dir_verifier); 799 trace_nfs_readdir_lookup(d_inode(parent), dentry, 0); 800 out: 801 dput(dentry); 802 } 803 804 static int nfs_readdir_entry_decode(struct nfs_readdir_descriptor *desc, 805 struct nfs_entry *entry, 806 struct xdr_stream *stream) 807 { 808 int ret; 809 810 if (entry->fattr->label) 811 entry->fattr->label->len = NFS4_MAXLABELLEN; 812 ret = xdr_decode(desc, entry, stream); 813 if (ret || !desc->plus) 814 return ret; 815 nfs_prime_dcache(file_dentry(desc->file), entry, desc->dir_verifier); 816 return 0; 817 } 818 819 /* Perform conversion from xdr to cache array */ 820 static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc, 821 struct nfs_entry *entry, 822 struct page **xdr_pages, unsigned int buflen, 823 struct page **arrays, size_t narrays, 824 u64 change_attr) 825 { 826 struct address_space *mapping = desc->file->f_mapping; 827 struct xdr_stream stream; 828 struct xdr_buf buf; 829 struct page *scratch, *new, *page = *arrays; 830 u64 cookie; 831 int status; 832 833 scratch = alloc_page(GFP_KERNEL); 834 if (scratch == NULL) 835 return -ENOMEM; 836 837 xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen); 838 xdr_set_scratch_page(&stream, scratch); 839 840 do { 841 status = nfs_readdir_entry_decode(desc, entry, &stream); 842 if (status != 0) 843 break; 844 845 status = nfs_readdir_page_array_append(page, entry, &cookie); 846 if (status != -ENOSPC) 847 continue; 848 849 if (page->mapping != mapping) { 850 if (!--narrays) 851 break; 852 new = nfs_readdir_page_array_alloc(cookie, GFP_KERNEL); 853 if (!new) 854 break; 855 arrays++; 856 *arrays = page = new; 857 } else { 858 new = nfs_readdir_page_get_next(mapping, cookie, 859 change_attr); 860 if (!new) 861 break; 862 if (page != *arrays) 863 nfs_readdir_page_unlock_and_put(page); 864 page = new; 865 } 866 desc->page_index_max++; 867 status = nfs_readdir_page_array_append(page, entry, &cookie); 868 } while (!status && !entry->eof); 869 870 switch (status) { 871 case -EBADCOOKIE: 872 if (!entry->eof) 873 break; 874 nfs_readdir_page_set_eof(page); 875 fallthrough; 876 case -EAGAIN: 877 status = 0; 878 break; 879 case -ENOSPC: 880 status = 0; 881 if (!desc->plus) 882 break; 883 while (!nfs_readdir_entry_decode(desc, entry, &stream)) 884 ; 885 } 886 887 if (page != *arrays) 888 nfs_readdir_page_unlock_and_put(page); 889 890 put_page(scratch); 891 return status; 892 } 893 894 static void nfs_readdir_free_pages(struct page **pages, size_t npages) 895 { 896 while (npages--) 897 put_page(pages[npages]); 898 kfree(pages); 899 } 900 901 /* 902 * nfs_readdir_alloc_pages() will allocate pages that must be freed with a call 903 * to nfs_readdir_free_pages() 904 */ 905 static struct page **nfs_readdir_alloc_pages(size_t npages) 906 { 907 struct page **pages; 908 size_t i; 909 910 pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL); 911 if (!pages) 912 return NULL; 913 for (i = 0; i < npages; i++) { 914 struct page *page = alloc_page(GFP_KERNEL); 915 if (page == NULL) 916 goto out_freepages; 917 pages[i] = page; 918 } 919 return pages; 920 921 out_freepages: 922 nfs_readdir_free_pages(pages, i); 923 return NULL; 924 } 925 926 static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc, 927 __be32 *verf_arg, __be32 *verf_res, 928 struct page **arrays, size_t narrays) 929 { 930 u64 change_attr; 931 struct page **pages; 932 struct page *page = *arrays; 933 struct nfs_entry *entry; 934 size_t array_size; 935 struct inode *inode = file_inode(desc->file); 936 unsigned int dtsize = desc->dtsize; 937 unsigned int pglen; 938 int status = -ENOMEM; 939 940 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 941 if (!entry) 942 return -ENOMEM; 943 entry->cookie = nfs_readdir_page_last_cookie(page); 944 entry->fh = nfs_alloc_fhandle(); 945 entry->fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode)); 946 entry->server = NFS_SERVER(inode); 947 if (entry->fh == NULL || entry->fattr == NULL) 948 goto out; 949 950 array_size = (dtsize + PAGE_SIZE - 1) >> PAGE_SHIFT; 951 pages = nfs_readdir_alloc_pages(array_size); 952 if (!pages) 953 goto out; 954 955 change_attr = inode_peek_iversion_raw(inode); 956 status = nfs_readdir_xdr_filler(desc, verf_arg, entry->cookie, pages, 957 dtsize, verf_res); 958 if (status < 0) 959 goto free_pages; 960 961 pglen = status; 962 if (pglen != 0) 963 status = nfs_readdir_page_filler(desc, entry, pages, pglen, 964 arrays, narrays, change_attr); 965 else 966 nfs_readdir_page_set_eof(page); 967 desc->buffer_fills++; 968 969 free_pages: 970 nfs_readdir_free_pages(pages, array_size); 971 out: 972 nfs_free_fattr(entry->fattr); 973 nfs_free_fhandle(entry->fh); 974 kfree(entry); 975 return status; 976 } 977 978 static void nfs_readdir_page_put(struct nfs_readdir_descriptor *desc) 979 { 980 put_page(desc->page); 981 desc->page = NULL; 982 } 983 984 static void 985 nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc) 986 { 987 unlock_page(desc->page); 988 nfs_readdir_page_put(desc); 989 } 990 991 static struct page * 992 nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc) 993 { 994 struct address_space *mapping = desc->file->f_mapping; 995 u64 change_attr = inode_peek_iversion_raw(mapping->host); 996 u64 cookie = desc->last_cookie; 997 struct page *page; 998 999 page = nfs_readdir_page_get_locked(mapping, cookie, change_attr); 1000 if (!page) 1001 return NULL; 1002 if (desc->clear_cache && !nfs_readdir_page_needs_filling(page)) 1003 nfs_readdir_page_reinit_array(page, cookie, change_attr); 1004 return page; 1005 } 1006 1007 /* 1008 * Returns 0 if desc->dir_cookie was found on page desc->page_index 1009 * and locks the page to prevent removal from the page cache. 1010 */ 1011 static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc) 1012 { 1013 struct inode *inode = file_inode(desc->file); 1014 struct nfs_inode *nfsi = NFS_I(inode); 1015 __be32 verf[NFS_DIR_VERIFIER_SIZE]; 1016 int res; 1017 1018 desc->page = nfs_readdir_page_get_cached(desc); 1019 if (!desc->page) 1020 return -ENOMEM; 1021 if (nfs_readdir_page_needs_filling(desc->page)) { 1022 /* Grow the dtsize if we had to go back for more pages */ 1023 if (desc->page_index == desc->page_index_max) 1024 nfs_grow_dtsize(desc); 1025 desc->page_index_max = desc->page_index; 1026 trace_nfs_readdir_cache_fill(desc->file, nfsi->cookieverf, 1027 desc->last_cookie, 1028 desc->page->index, desc->dtsize); 1029 res = nfs_readdir_xdr_to_array(desc, nfsi->cookieverf, verf, 1030 &desc->page, 1); 1031 if (res < 0) { 1032 nfs_readdir_page_unlock_and_put_cached(desc); 1033 trace_nfs_readdir_cache_fill_done(inode, res); 1034 if (res == -EBADCOOKIE || res == -ENOTSYNC) { 1035 invalidate_inode_pages2(desc->file->f_mapping); 1036 nfs_readdir_rewind_search(desc); 1037 trace_nfs_readdir_invalidate_cache_range( 1038 inode, 0, MAX_LFS_FILESIZE); 1039 return -EAGAIN; 1040 } 1041 return res; 1042 } 1043 /* 1044 * Set the cookie verifier if the page cache was empty 1045 */ 1046 if (desc->last_cookie == 0 && 1047 memcmp(nfsi->cookieverf, verf, sizeof(nfsi->cookieverf))) { 1048 memcpy(nfsi->cookieverf, verf, 1049 sizeof(nfsi->cookieverf)); 1050 invalidate_inode_pages2_range(desc->file->f_mapping, 1, 1051 -1); 1052 trace_nfs_readdir_invalidate_cache_range( 1053 inode, 1, MAX_LFS_FILESIZE); 1054 } 1055 desc->clear_cache = false; 1056 } 1057 res = nfs_readdir_search_array(desc); 1058 if (res == 0) 1059 return 0; 1060 nfs_readdir_page_unlock_and_put_cached(desc); 1061 return res; 1062 } 1063 1064 /* Search for desc->dir_cookie from the beginning of the page cache */ 1065 static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc) 1066 { 1067 int res; 1068 1069 do { 1070 res = find_and_lock_cache_page(desc); 1071 } while (res == -EAGAIN); 1072 return res; 1073 } 1074 1075 /* 1076 * Once we've found the start of the dirent within a page: fill 'er up... 1077 */ 1078 static void nfs_do_filldir(struct nfs_readdir_descriptor *desc, 1079 const __be32 *verf) 1080 { 1081 struct file *file = desc->file; 1082 struct nfs_cache_array *array; 1083 unsigned int i; 1084 1085 array = kmap(desc->page); 1086 for (i = desc->cache_entry_index; i < array->size; i++) { 1087 struct nfs_cache_array_entry *ent; 1088 1089 ent = &array->array[i]; 1090 if (!dir_emit(desc->ctx, ent->name, ent->name_len, 1091 nfs_compat_user_ino64(ent->ino), ent->d_type)) { 1092 desc->eob = true; 1093 break; 1094 } 1095 memcpy(desc->verf, verf, sizeof(desc->verf)); 1096 if (i == array->size - 1) { 1097 desc->dir_cookie = array->last_cookie; 1098 nfs_readdir_seek_next_array(array, desc); 1099 } else { 1100 desc->dir_cookie = array->array[i + 1].cookie; 1101 desc->last_cookie = array->array[0].cookie; 1102 } 1103 if (nfs_readdir_use_cookie(file)) 1104 desc->ctx->pos = desc->dir_cookie; 1105 else 1106 desc->ctx->pos++; 1107 } 1108 if (array->page_is_eof) 1109 desc->eof = !desc->eob; 1110 1111 kunmap(desc->page); 1112 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %llu\n", 1113 (unsigned long long)desc->dir_cookie); 1114 } 1115 1116 /* 1117 * If we cannot find a cookie in our cache, we suspect that this is 1118 * because it points to a deleted file, so we ask the server to return 1119 * whatever it thinks is the next entry. We then feed this to filldir. 1120 * If all goes well, we should then be able to find our way round the 1121 * cache on the next call to readdir_search_pagecache(); 1122 * 1123 * NOTE: we cannot add the anonymous page to the pagecache because 1124 * the data it contains might not be page aligned. Besides, 1125 * we should already have a complete representation of the 1126 * directory in the page cache by the time we get here. 1127 */ 1128 static int uncached_readdir(struct nfs_readdir_descriptor *desc) 1129 { 1130 struct page **arrays; 1131 size_t i, sz = 512; 1132 __be32 verf[NFS_DIR_VERIFIER_SIZE]; 1133 int status = -ENOMEM; 1134 1135 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %llu\n", 1136 (unsigned long long)desc->dir_cookie); 1137 1138 arrays = kcalloc(sz, sizeof(*arrays), GFP_KERNEL); 1139 if (!arrays) 1140 goto out; 1141 arrays[0] = nfs_readdir_page_array_alloc(desc->dir_cookie, GFP_KERNEL); 1142 if (!arrays[0]) 1143 goto out; 1144 1145 desc->page_index = 0; 1146 desc->cache_entry_index = 0; 1147 desc->last_cookie = desc->dir_cookie; 1148 desc->page_index_max = 0; 1149 1150 trace_nfs_readdir_uncached(desc->file, desc->verf, desc->last_cookie, 1151 -1, desc->dtsize); 1152 1153 status = nfs_readdir_xdr_to_array(desc, desc->verf, verf, arrays, sz); 1154 if (status < 0) { 1155 trace_nfs_readdir_uncached_done(file_inode(desc->file), status); 1156 goto out_free; 1157 } 1158 1159 for (i = 0; !desc->eob && i < sz && arrays[i]; i++) { 1160 desc->page = arrays[i]; 1161 nfs_do_filldir(desc, verf); 1162 } 1163 desc->page = NULL; 1164 1165 /* 1166 * Grow the dtsize if we have to go back for more pages, 1167 * or shrink it if we're reading too many. 1168 */ 1169 if (!desc->eof) { 1170 if (!desc->eob) 1171 nfs_grow_dtsize(desc); 1172 else if (desc->buffer_fills == 1 && 1173 i < (desc->page_index_max >> 1)) 1174 nfs_shrink_dtsize(desc); 1175 } 1176 out_free: 1177 for (i = 0; i < sz && arrays[i]; i++) 1178 nfs_readdir_page_array_free(arrays[i]); 1179 out: 1180 if (!nfs_readdir_use_cookie(desc->file)) 1181 nfs_readdir_rewind_search(desc); 1182 desc->page_index_max = -1; 1183 kfree(arrays); 1184 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status); 1185 return status; 1186 } 1187 1188 #define NFS_READDIR_CACHE_MISS_THRESHOLD (16UL) 1189 1190 static bool nfs_readdir_handle_cache_misses(struct inode *inode, 1191 struct nfs_readdir_descriptor *desc, 1192 unsigned int cache_misses, 1193 bool force_clear) 1194 { 1195 if (desc->ctx->pos == 0 || !desc->plus) 1196 return false; 1197 if (cache_misses <= NFS_READDIR_CACHE_MISS_THRESHOLD && !force_clear) 1198 return false; 1199 trace_nfs_readdir_force_readdirplus(inode); 1200 return true; 1201 } 1202 1203 /* The file offset position represents the dirent entry number. A 1204 last cookie cache takes care of the common case of reading the 1205 whole directory. 1206 */ 1207 static int nfs_readdir(struct file *file, struct dir_context *ctx) 1208 { 1209 struct dentry *dentry = file_dentry(file); 1210 struct inode *inode = d_inode(dentry); 1211 struct nfs_inode *nfsi = NFS_I(inode); 1212 struct nfs_open_dir_context *dir_ctx = file->private_data; 1213 struct nfs_readdir_descriptor *desc; 1214 unsigned int cache_hits, cache_misses; 1215 bool force_clear; 1216 int res; 1217 1218 dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n", 1219 file, (long long)ctx->pos); 1220 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); 1221 1222 /* 1223 * ctx->pos points to the dirent entry number. 1224 * *desc->dir_cookie has the cookie for the next entry. We have 1225 * to either find the entry with the appropriate number or 1226 * revalidate the cookie. 1227 */ 1228 nfs_revalidate_mapping(inode, file->f_mapping); 1229 1230 res = -ENOMEM; 1231 desc = kzalloc(sizeof(*desc), GFP_KERNEL); 1232 if (!desc) 1233 goto out; 1234 desc->file = file; 1235 desc->ctx = ctx; 1236 desc->page_index_max = -1; 1237 1238 spin_lock(&file->f_lock); 1239 desc->dir_cookie = dir_ctx->dir_cookie; 1240 desc->page_index = dir_ctx->page_index; 1241 desc->last_cookie = dir_ctx->last_cookie; 1242 desc->attr_gencount = dir_ctx->attr_gencount; 1243 desc->eof = dir_ctx->eof; 1244 nfs_set_dtsize(desc, dir_ctx->dtsize); 1245 memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf)); 1246 cache_hits = atomic_xchg(&dir_ctx->cache_hits, 0); 1247 cache_misses = atomic_xchg(&dir_ctx->cache_misses, 0); 1248 force_clear = dir_ctx->force_clear; 1249 spin_unlock(&file->f_lock); 1250 1251 if (desc->eof) { 1252 res = 0; 1253 goto out_free; 1254 } 1255 1256 desc->plus = nfs_use_readdirplus(inode, ctx, cache_hits, cache_misses); 1257 force_clear = nfs_readdir_handle_cache_misses(inode, desc, cache_misses, 1258 force_clear); 1259 desc->clear_cache = force_clear; 1260 1261 do { 1262 res = readdir_search_pagecache(desc); 1263 1264 if (res == -EBADCOOKIE) { 1265 res = 0; 1266 /* This means either end of directory */ 1267 if (desc->dir_cookie && !desc->eof) { 1268 /* Or that the server has 'lost' a cookie */ 1269 res = uncached_readdir(desc); 1270 if (res == 0) 1271 continue; 1272 if (res == -EBADCOOKIE || res == -ENOTSYNC) 1273 res = 0; 1274 } 1275 break; 1276 } 1277 if (res == -ETOOSMALL && desc->plus) { 1278 nfs_zap_caches(inode); 1279 desc->plus = false; 1280 desc->eof = false; 1281 continue; 1282 } 1283 if (res < 0) 1284 break; 1285 1286 nfs_do_filldir(desc, nfsi->cookieverf); 1287 nfs_readdir_page_unlock_and_put_cached(desc); 1288 if (desc->page_index == desc->page_index_max) 1289 desc->clear_cache = force_clear; 1290 } while (!desc->eob && !desc->eof); 1291 1292 spin_lock(&file->f_lock); 1293 dir_ctx->dir_cookie = desc->dir_cookie; 1294 dir_ctx->last_cookie = desc->last_cookie; 1295 dir_ctx->attr_gencount = desc->attr_gencount; 1296 dir_ctx->page_index = desc->page_index; 1297 dir_ctx->force_clear = force_clear; 1298 dir_ctx->eof = desc->eof; 1299 dir_ctx->dtsize = desc->dtsize; 1300 memcpy(dir_ctx->verf, desc->verf, sizeof(dir_ctx->verf)); 1301 spin_unlock(&file->f_lock); 1302 out_free: 1303 kfree(desc); 1304 1305 out: 1306 dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res); 1307 return res; 1308 } 1309 1310 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) 1311 { 1312 struct nfs_open_dir_context *dir_ctx = filp->private_data; 1313 1314 dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n", 1315 filp, offset, whence); 1316 1317 switch (whence) { 1318 default: 1319 return -EINVAL; 1320 case SEEK_SET: 1321 if (offset < 0) 1322 return -EINVAL; 1323 spin_lock(&filp->f_lock); 1324 break; 1325 case SEEK_CUR: 1326 if (offset == 0) 1327 return filp->f_pos; 1328 spin_lock(&filp->f_lock); 1329 offset += filp->f_pos; 1330 if (offset < 0) { 1331 spin_unlock(&filp->f_lock); 1332 return -EINVAL; 1333 } 1334 } 1335 if (offset != filp->f_pos) { 1336 filp->f_pos = offset; 1337 dir_ctx->page_index = 0; 1338 if (!nfs_readdir_use_cookie(filp)) { 1339 dir_ctx->dir_cookie = 0; 1340 dir_ctx->last_cookie = 0; 1341 } else { 1342 dir_ctx->dir_cookie = offset; 1343 dir_ctx->last_cookie = offset; 1344 } 1345 dir_ctx->eof = false; 1346 } 1347 spin_unlock(&filp->f_lock); 1348 return offset; 1349 } 1350 1351 /* 1352 * All directory operations under NFS are synchronous, so fsync() 1353 * is a dummy operation. 1354 */ 1355 static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end, 1356 int datasync) 1357 { 1358 dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync); 1359 1360 nfs_inc_stats(file_inode(filp), NFSIOS_VFSFSYNC); 1361 return 0; 1362 } 1363 1364 /** 1365 * nfs_force_lookup_revalidate - Mark the directory as having changed 1366 * @dir: pointer to directory inode 1367 * 1368 * This forces the revalidation code in nfs_lookup_revalidate() to do a 1369 * full lookup on all child dentries of 'dir' whenever a change occurs 1370 * on the server that might have invalidated our dcache. 1371 * 1372 * Note that we reserve bit '0' as a tag to let us know when a dentry 1373 * was revalidated while holding a delegation on its inode. 1374 * 1375 * The caller should be holding dir->i_lock 1376 */ 1377 void nfs_force_lookup_revalidate(struct inode *dir) 1378 { 1379 NFS_I(dir)->cache_change_attribute += 2; 1380 } 1381 EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate); 1382 1383 /** 1384 * nfs_verify_change_attribute - Detects NFS remote directory changes 1385 * @dir: pointer to parent directory inode 1386 * @verf: previously saved change attribute 1387 * 1388 * Return "false" if the verifiers doesn't match the change attribute. 1389 * This would usually indicate that the directory contents have changed on 1390 * the server, and that any dentries need revalidating. 1391 */ 1392 static bool nfs_verify_change_attribute(struct inode *dir, unsigned long verf) 1393 { 1394 return (verf & ~1UL) == nfs_save_change_attribute(dir); 1395 } 1396 1397 static void nfs_set_verifier_delegated(unsigned long *verf) 1398 { 1399 *verf |= 1UL; 1400 } 1401 1402 #if IS_ENABLED(CONFIG_NFS_V4) 1403 static void nfs_unset_verifier_delegated(unsigned long *verf) 1404 { 1405 *verf &= ~1UL; 1406 } 1407 #endif /* IS_ENABLED(CONFIG_NFS_V4) */ 1408 1409 static bool nfs_test_verifier_delegated(unsigned long verf) 1410 { 1411 return verf & 1; 1412 } 1413 1414 static bool nfs_verifier_is_delegated(struct dentry *dentry) 1415 { 1416 return nfs_test_verifier_delegated(dentry->d_time); 1417 } 1418 1419 static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf) 1420 { 1421 struct inode *inode = d_inode(dentry); 1422 struct inode *dir = d_inode(dentry->d_parent); 1423 1424 if (!nfs_verify_change_attribute(dir, verf)) 1425 return; 1426 if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) 1427 nfs_set_verifier_delegated(&verf); 1428 dentry->d_time = verf; 1429 } 1430 1431 /** 1432 * nfs_set_verifier - save a parent directory verifier in the dentry 1433 * @dentry: pointer to dentry 1434 * @verf: verifier to save 1435 * 1436 * Saves the parent directory verifier in @dentry. If the inode has 1437 * a delegation, we also tag the dentry as having been revalidated 1438 * while holding a delegation so that we know we don't have to 1439 * look it up again after a directory change. 1440 */ 1441 void nfs_set_verifier(struct dentry *dentry, unsigned long verf) 1442 { 1443 1444 spin_lock(&dentry->d_lock); 1445 nfs_set_verifier_locked(dentry, verf); 1446 spin_unlock(&dentry->d_lock); 1447 } 1448 EXPORT_SYMBOL_GPL(nfs_set_verifier); 1449 1450 #if IS_ENABLED(CONFIG_NFS_V4) 1451 /** 1452 * nfs_clear_verifier_delegated - clear the dir verifier delegation tag 1453 * @inode: pointer to inode 1454 * 1455 * Iterates through the dentries in the inode alias list and clears 1456 * the tag used to indicate that the dentry has been revalidated 1457 * while holding a delegation. 1458 * This function is intended for use when the delegation is being 1459 * returned or revoked. 1460 */ 1461 void nfs_clear_verifier_delegated(struct inode *inode) 1462 { 1463 struct dentry *alias; 1464 1465 if (!inode) 1466 return; 1467 spin_lock(&inode->i_lock); 1468 hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { 1469 spin_lock(&alias->d_lock); 1470 nfs_unset_verifier_delegated(&alias->d_time); 1471 spin_unlock(&alias->d_lock); 1472 } 1473 spin_unlock(&inode->i_lock); 1474 } 1475 EXPORT_SYMBOL_GPL(nfs_clear_verifier_delegated); 1476 #endif /* IS_ENABLED(CONFIG_NFS_V4) */ 1477 1478 static int nfs_dentry_verify_change(struct inode *dir, struct dentry *dentry) 1479 { 1480 if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE) && 1481 d_really_is_negative(dentry)) 1482 return dentry->d_time == inode_peek_iversion_raw(dir); 1483 return nfs_verify_change_attribute(dir, dentry->d_time); 1484 } 1485 1486 /* 1487 * A check for whether or not the parent directory has changed. 1488 * In the case it has, we assume that the dentries are untrustworthy 1489 * and may need to be looked up again. 1490 * If rcu_walk prevents us from performing a full check, return 0. 1491 */ 1492 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry, 1493 int rcu_walk) 1494 { 1495 if (IS_ROOT(dentry)) 1496 return 1; 1497 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE) 1498 return 0; 1499 if (!nfs_dentry_verify_change(dir, dentry)) 1500 return 0; 1501 /* Revalidate nfsi->cache_change_attribute before we declare a match */ 1502 if (nfs_mapping_need_revalidate_inode(dir)) { 1503 if (rcu_walk) 1504 return 0; 1505 if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) 1506 return 0; 1507 } 1508 if (!nfs_dentry_verify_change(dir, dentry)) 1509 return 0; 1510 return 1; 1511 } 1512 1513 /* 1514 * Use intent information to check whether or not we're going to do 1515 * an O_EXCL create using this path component. 1516 */ 1517 static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags) 1518 { 1519 if (NFS_PROTO(dir)->version == 2) 1520 return 0; 1521 return flags & LOOKUP_EXCL; 1522 } 1523 1524 /* 1525 * Inode and filehandle revalidation for lookups. 1526 * 1527 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, 1528 * or if the intent information indicates that we're about to open this 1529 * particular file and the "nocto" mount flag is not set. 1530 * 1531 */ 1532 static 1533 int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags) 1534 { 1535 struct nfs_server *server = NFS_SERVER(inode); 1536 int ret; 1537 1538 if (IS_AUTOMOUNT(inode)) 1539 return 0; 1540 1541 if (flags & LOOKUP_OPEN) { 1542 switch (inode->i_mode & S_IFMT) { 1543 case S_IFREG: 1544 /* A NFSv4 OPEN will revalidate later */ 1545 if (server->caps & NFS_CAP_ATOMIC_OPEN) 1546 goto out; 1547 fallthrough; 1548 case S_IFDIR: 1549 if (server->flags & NFS_MOUNT_NOCTO) 1550 break; 1551 /* NFS close-to-open cache consistency validation */ 1552 goto out_force; 1553 } 1554 } 1555 1556 /* VFS wants an on-the-wire revalidation */ 1557 if (flags & LOOKUP_REVAL) 1558 goto out_force; 1559 out: 1560 if (inode->i_nlink > 0 || 1561 (inode->i_nlink == 0 && 1562 test_bit(NFS_INO_PRESERVE_UNLINKED, &NFS_I(inode)->flags))) 1563 return 0; 1564 else 1565 return -ESTALE; 1566 out_force: 1567 if (flags & LOOKUP_RCU) 1568 return -ECHILD; 1569 ret = __nfs_revalidate_inode(server, inode); 1570 if (ret != 0) 1571 return ret; 1572 goto out; 1573 } 1574 1575 static void nfs_mark_dir_for_revalidate(struct inode *inode) 1576 { 1577 spin_lock(&inode->i_lock); 1578 nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE); 1579 spin_unlock(&inode->i_lock); 1580 } 1581 1582 /* 1583 * We judge how long we want to trust negative 1584 * dentries by looking at the parent inode mtime. 1585 * 1586 * If parent mtime has changed, we revalidate, else we wait for a 1587 * period corresponding to the parent's attribute cache timeout value. 1588 * 1589 * If LOOKUP_RCU prevents us from performing a full check, return 1 1590 * suggesting a reval is needed. 1591 * 1592 * Note that when creating a new file, or looking up a rename target, 1593 * then it shouldn't be necessary to revalidate a negative dentry. 1594 */ 1595 static inline 1596 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 1597 unsigned int flags) 1598 { 1599 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) 1600 return 0; 1601 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) 1602 return 1; 1603 /* Case insensitive server? Revalidate negative dentries */ 1604 if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) 1605 return 1; 1606 return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU); 1607 } 1608 1609 static int 1610 nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry, 1611 struct inode *inode, int error) 1612 { 1613 switch (error) { 1614 case 1: 1615 break; 1616 case 0: 1617 /* 1618 * We can't d_drop the root of a disconnected tree: 1619 * its d_hash is on the s_anon list and d_drop() would hide 1620 * it from shrink_dcache_for_unmount(), leading to busy 1621 * inodes on unmount and further oopses. 1622 */ 1623 if (inode && IS_ROOT(dentry)) 1624 error = 1; 1625 break; 1626 } 1627 trace_nfs_lookup_revalidate_exit(dir, dentry, 0, error); 1628 return error; 1629 } 1630 1631 static int 1632 nfs_lookup_revalidate_negative(struct inode *dir, struct dentry *dentry, 1633 unsigned int flags) 1634 { 1635 int ret = 1; 1636 if (nfs_neg_need_reval(dir, dentry, flags)) { 1637 if (flags & LOOKUP_RCU) 1638 return -ECHILD; 1639 ret = 0; 1640 } 1641 return nfs_lookup_revalidate_done(dir, dentry, NULL, ret); 1642 } 1643 1644 static int 1645 nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry, 1646 struct inode *inode) 1647 { 1648 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1649 return nfs_lookup_revalidate_done(dir, dentry, inode, 1); 1650 } 1651 1652 static int nfs_lookup_revalidate_dentry(struct inode *dir, 1653 struct dentry *dentry, 1654 struct inode *inode, unsigned int flags) 1655 { 1656 struct nfs_fh *fhandle; 1657 struct nfs_fattr *fattr; 1658 unsigned long dir_verifier; 1659 int ret; 1660 1661 trace_nfs_lookup_revalidate_enter(dir, dentry, flags); 1662 1663 ret = -ENOMEM; 1664 fhandle = nfs_alloc_fhandle(); 1665 fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode)); 1666 if (fhandle == NULL || fattr == NULL) 1667 goto out; 1668 1669 dir_verifier = nfs_save_change_attribute(dir); 1670 ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr); 1671 if (ret < 0) { 1672 switch (ret) { 1673 case -ESTALE: 1674 case -ENOENT: 1675 ret = 0; 1676 break; 1677 case -ETIMEDOUT: 1678 if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL) 1679 ret = 1; 1680 } 1681 goto out; 1682 } 1683 1684 /* Request help from readdirplus */ 1685 nfs_lookup_advise_force_readdirplus(dir, flags); 1686 1687 ret = 0; 1688 if (nfs_compare_fh(NFS_FH(inode), fhandle)) 1689 goto out; 1690 if (nfs_refresh_inode(inode, fattr) < 0) 1691 goto out; 1692 1693 nfs_setsecurity(inode, fattr); 1694 nfs_set_verifier(dentry, dir_verifier); 1695 1696 ret = 1; 1697 out: 1698 nfs_free_fattr(fattr); 1699 nfs_free_fhandle(fhandle); 1700 1701 /* 1702 * If the lookup failed despite the dentry change attribute being 1703 * a match, then we should revalidate the directory cache. 1704 */ 1705 if (!ret && nfs_dentry_verify_change(dir, dentry)) 1706 nfs_mark_dir_for_revalidate(dir); 1707 return nfs_lookup_revalidate_done(dir, dentry, inode, ret); 1708 } 1709 1710 /* 1711 * This is called every time the dcache has a lookup hit, 1712 * and we should check whether we can really trust that 1713 * lookup. 1714 * 1715 * NOTE! The hit can be a negative hit too, don't assume 1716 * we have an inode! 1717 * 1718 * If the parent directory is seen to have changed, we throw out the 1719 * cached dentry and do a new lookup. 1720 */ 1721 static int 1722 nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry, 1723 unsigned int flags) 1724 { 1725 struct inode *inode; 1726 int error; 1727 1728 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); 1729 inode = d_inode(dentry); 1730 1731 if (!inode) 1732 return nfs_lookup_revalidate_negative(dir, dentry, flags); 1733 1734 if (is_bad_inode(inode)) { 1735 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", 1736 __func__, dentry); 1737 goto out_bad; 1738 } 1739 1740 if (nfs_verifier_is_delegated(dentry)) 1741 return nfs_lookup_revalidate_delegated(dir, dentry, inode); 1742 1743 /* Force a full look up iff the parent directory has changed */ 1744 if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) && 1745 nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) { 1746 error = nfs_lookup_verify_inode(inode, flags); 1747 if (error) { 1748 if (error == -ESTALE) 1749 nfs_mark_dir_for_revalidate(dir); 1750 goto out_bad; 1751 } 1752 goto out_valid; 1753 } 1754 1755 if (flags & LOOKUP_RCU) 1756 return -ECHILD; 1757 1758 if (NFS_STALE(inode)) 1759 goto out_bad; 1760 1761 return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags); 1762 out_valid: 1763 return nfs_lookup_revalidate_done(dir, dentry, inode, 1); 1764 out_bad: 1765 if (flags & LOOKUP_RCU) 1766 return -ECHILD; 1767 return nfs_lookup_revalidate_done(dir, dentry, inode, 0); 1768 } 1769 1770 static int 1771 __nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags, 1772 int (*reval)(struct inode *, struct dentry *, unsigned int)) 1773 { 1774 struct dentry *parent; 1775 struct inode *dir; 1776 int ret; 1777 1778 if (flags & LOOKUP_RCU) { 1779 parent = READ_ONCE(dentry->d_parent); 1780 dir = d_inode_rcu(parent); 1781 if (!dir) 1782 return -ECHILD; 1783 ret = reval(dir, dentry, flags); 1784 if (parent != READ_ONCE(dentry->d_parent)) 1785 return -ECHILD; 1786 } else { 1787 parent = dget_parent(dentry); 1788 ret = reval(d_inode(parent), dentry, flags); 1789 dput(parent); 1790 } 1791 return ret; 1792 } 1793 1794 static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags) 1795 { 1796 return __nfs_lookup_revalidate(dentry, flags, nfs_do_lookup_revalidate); 1797 } 1798 1799 /* 1800 * A weaker form of d_revalidate for revalidating just the d_inode(dentry) 1801 * when we don't really care about the dentry name. This is called when a 1802 * pathwalk ends on a dentry that was not found via a normal lookup in the 1803 * parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals). 1804 * 1805 * In this situation, we just want to verify that the inode itself is OK 1806 * since the dentry might have changed on the server. 1807 */ 1808 static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags) 1809 { 1810 struct inode *inode = d_inode(dentry); 1811 int error = 0; 1812 1813 /* 1814 * I believe we can only get a negative dentry here in the case of a 1815 * procfs-style symlink. Just assume it's correct for now, but we may 1816 * eventually need to do something more here. 1817 */ 1818 if (!inode) { 1819 dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n", 1820 __func__, dentry); 1821 return 1; 1822 } 1823 1824 if (is_bad_inode(inode)) { 1825 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", 1826 __func__, dentry); 1827 return 0; 1828 } 1829 1830 error = nfs_lookup_verify_inode(inode, flags); 1831 dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n", 1832 __func__, inode->i_ino, error ? "invalid" : "valid"); 1833 return !error; 1834 } 1835 1836 /* 1837 * This is called from dput() when d_count is going to 0. 1838 */ 1839 static int nfs_dentry_delete(const struct dentry *dentry) 1840 { 1841 dfprintk(VFS, "NFS: dentry_delete(%pd2, %x)\n", 1842 dentry, dentry->d_flags); 1843 1844 /* Unhash any dentry with a stale inode */ 1845 if (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry))) 1846 return 1; 1847 1848 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1849 /* Unhash it, so that ->d_iput() would be called */ 1850 return 1; 1851 } 1852 if (!(dentry->d_sb->s_flags & SB_ACTIVE)) { 1853 /* Unhash it, so that ancestors of killed async unlink 1854 * files will be cleaned up during umount */ 1855 return 1; 1856 } 1857 return 0; 1858 1859 } 1860 1861 /* Ensure that we revalidate inode->i_nlink */ 1862 static void nfs_drop_nlink(struct inode *inode) 1863 { 1864 spin_lock(&inode->i_lock); 1865 /* drop the inode if we're reasonably sure this is the last link */ 1866 if (inode->i_nlink > 0) 1867 drop_nlink(inode); 1868 NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter(); 1869 nfs_set_cache_invalid( 1870 inode, NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME | 1871 NFS_INO_INVALID_NLINK); 1872 spin_unlock(&inode->i_lock); 1873 } 1874 1875 /* 1876 * Called when the dentry loses inode. 1877 * We use it to clean up silly-renamed files. 1878 */ 1879 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) 1880 { 1881 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1882 nfs_complete_unlink(dentry, inode); 1883 nfs_drop_nlink(inode); 1884 } 1885 iput(inode); 1886 } 1887 1888 static void nfs_d_release(struct dentry *dentry) 1889 { 1890 /* free cached devname value, if it survived that far */ 1891 if (unlikely(dentry->d_fsdata)) { 1892 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 1893 WARN_ON(1); 1894 else 1895 kfree(dentry->d_fsdata); 1896 } 1897 } 1898 1899 const struct dentry_operations nfs_dentry_operations = { 1900 .d_revalidate = nfs_lookup_revalidate, 1901 .d_weak_revalidate = nfs_weak_revalidate, 1902 .d_delete = nfs_dentry_delete, 1903 .d_iput = nfs_dentry_iput, 1904 .d_automount = nfs_d_automount, 1905 .d_release = nfs_d_release, 1906 }; 1907 EXPORT_SYMBOL_GPL(nfs_dentry_operations); 1908 1909 struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) 1910 { 1911 struct dentry *res; 1912 struct inode *inode = NULL; 1913 struct nfs_fh *fhandle = NULL; 1914 struct nfs_fattr *fattr = NULL; 1915 unsigned long dir_verifier; 1916 int error; 1917 1918 dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry); 1919 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); 1920 1921 if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen)) 1922 return ERR_PTR(-ENAMETOOLONG); 1923 1924 /* 1925 * If we're doing an exclusive create, optimize away the lookup 1926 * but don't hash the dentry. 1927 */ 1928 if (nfs_is_exclusive_create(dir, flags) || flags & LOOKUP_RENAME_TARGET) 1929 return NULL; 1930 1931 res = ERR_PTR(-ENOMEM); 1932 fhandle = nfs_alloc_fhandle(); 1933 fattr = nfs_alloc_fattr_with_label(NFS_SERVER(dir)); 1934 if (fhandle == NULL || fattr == NULL) 1935 goto out; 1936 1937 dir_verifier = nfs_save_change_attribute(dir); 1938 trace_nfs_lookup_enter(dir, dentry, flags); 1939 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr); 1940 if (error == -ENOENT) { 1941 if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) 1942 dir_verifier = inode_peek_iversion_raw(dir); 1943 goto no_entry; 1944 } 1945 if (error < 0) { 1946 res = ERR_PTR(error); 1947 goto out; 1948 } 1949 inode = nfs_fhget(dentry->d_sb, fhandle, fattr); 1950 res = ERR_CAST(inode); 1951 if (IS_ERR(res)) 1952 goto out; 1953 1954 /* Notify readdir to use READDIRPLUS */ 1955 nfs_lookup_advise_force_readdirplus(dir, flags); 1956 1957 no_entry: 1958 res = d_splice_alias(inode, dentry); 1959 if (res != NULL) { 1960 if (IS_ERR(res)) 1961 goto out; 1962 dentry = res; 1963 } 1964 nfs_set_verifier(dentry, dir_verifier); 1965 out: 1966 trace_nfs_lookup_exit(dir, dentry, flags, PTR_ERR_OR_ZERO(res)); 1967 nfs_free_fattr(fattr); 1968 nfs_free_fhandle(fhandle); 1969 return res; 1970 } 1971 EXPORT_SYMBOL_GPL(nfs_lookup); 1972 1973 void nfs_d_prune_case_insensitive_aliases(struct inode *inode) 1974 { 1975 /* Case insensitive server? Revalidate dentries */ 1976 if (inode && nfs_server_capable(inode, NFS_CAP_CASE_INSENSITIVE)) 1977 d_prune_aliases(inode); 1978 } 1979 EXPORT_SYMBOL_GPL(nfs_d_prune_case_insensitive_aliases); 1980 1981 #if IS_ENABLED(CONFIG_NFS_V4) 1982 static int nfs4_lookup_revalidate(struct dentry *, unsigned int); 1983 1984 const struct dentry_operations nfs4_dentry_operations = { 1985 .d_revalidate = nfs4_lookup_revalidate, 1986 .d_weak_revalidate = nfs_weak_revalidate, 1987 .d_delete = nfs_dentry_delete, 1988 .d_iput = nfs_dentry_iput, 1989 .d_automount = nfs_d_automount, 1990 .d_release = nfs_d_release, 1991 }; 1992 EXPORT_SYMBOL_GPL(nfs4_dentry_operations); 1993 1994 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp) 1995 { 1996 return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp); 1997 } 1998 1999 static int do_open(struct inode *inode, struct file *filp) 2000 { 2001 nfs_fscache_open_file(inode, filp); 2002 return 0; 2003 } 2004 2005 static int nfs_finish_open(struct nfs_open_context *ctx, 2006 struct dentry *dentry, 2007 struct file *file, unsigned open_flags) 2008 { 2009 int err; 2010 2011 err = finish_open(file, dentry, do_open); 2012 if (err) 2013 goto out; 2014 if (S_ISREG(file->f_path.dentry->d_inode->i_mode)) 2015 nfs_file_set_open_context(file, ctx); 2016 else 2017 err = -EOPENSTALE; 2018 out: 2019 return err; 2020 } 2021 2022 int nfs_atomic_open(struct inode *dir, struct dentry *dentry, 2023 struct file *file, unsigned open_flags, 2024 umode_t mode) 2025 { 2026 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 2027 struct nfs_open_context *ctx; 2028 struct dentry *res; 2029 struct iattr attr = { .ia_valid = ATTR_OPEN }; 2030 struct inode *inode; 2031 unsigned int lookup_flags = 0; 2032 unsigned long dir_verifier; 2033 bool switched = false; 2034 int created = 0; 2035 int err; 2036 2037 /* Expect a negative dentry */ 2038 BUG_ON(d_inode(dentry)); 2039 2040 dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n", 2041 dir->i_sb->s_id, dir->i_ino, dentry); 2042 2043 err = nfs_check_flags(open_flags); 2044 if (err) 2045 return err; 2046 2047 /* NFS only supports OPEN on regular files */ 2048 if ((open_flags & O_DIRECTORY)) { 2049 if (!d_in_lookup(dentry)) { 2050 /* 2051 * Hashed negative dentry with O_DIRECTORY: dentry was 2052 * revalidated and is fine, no need to perform lookup 2053 * again 2054 */ 2055 return -ENOENT; 2056 } 2057 lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY; 2058 goto no_open; 2059 } 2060 2061 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 2062 return -ENAMETOOLONG; 2063 2064 if (open_flags & O_CREAT) { 2065 struct nfs_server *server = NFS_SERVER(dir); 2066 2067 if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK)) 2068 mode &= ~current_umask(); 2069 2070 attr.ia_valid |= ATTR_MODE; 2071 attr.ia_mode = mode; 2072 } 2073 if (open_flags & O_TRUNC) { 2074 attr.ia_valid |= ATTR_SIZE; 2075 attr.ia_size = 0; 2076 } 2077 2078 if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) { 2079 d_drop(dentry); 2080 switched = true; 2081 dentry = d_alloc_parallel(dentry->d_parent, 2082 &dentry->d_name, &wq); 2083 if (IS_ERR(dentry)) 2084 return PTR_ERR(dentry); 2085 if (unlikely(!d_in_lookup(dentry))) 2086 return finish_no_open(file, dentry); 2087 } 2088 2089 ctx = create_nfs_open_context(dentry, open_flags, file); 2090 err = PTR_ERR(ctx); 2091 if (IS_ERR(ctx)) 2092 goto out; 2093 2094 trace_nfs_atomic_open_enter(dir, ctx, open_flags); 2095 inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, &created); 2096 if (created) 2097 file->f_mode |= FMODE_CREATED; 2098 if (IS_ERR(inode)) { 2099 err = PTR_ERR(inode); 2100 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); 2101 put_nfs_open_context(ctx); 2102 d_drop(dentry); 2103 switch (err) { 2104 case -ENOENT: 2105 d_splice_alias(NULL, dentry); 2106 if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) 2107 dir_verifier = inode_peek_iversion_raw(dir); 2108 else 2109 dir_verifier = nfs_save_change_attribute(dir); 2110 nfs_set_verifier(dentry, dir_verifier); 2111 break; 2112 case -EISDIR: 2113 case -ENOTDIR: 2114 goto no_open; 2115 case -ELOOP: 2116 if (!(open_flags & O_NOFOLLOW)) 2117 goto no_open; 2118 break; 2119 /* case -EINVAL: */ 2120 default: 2121 break; 2122 } 2123 goto out; 2124 } 2125 2126 err = nfs_finish_open(ctx, ctx->dentry, file, open_flags); 2127 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); 2128 put_nfs_open_context(ctx); 2129 out: 2130 if (unlikely(switched)) { 2131 d_lookup_done(dentry); 2132 dput(dentry); 2133 } 2134 return err; 2135 2136 no_open: 2137 res = nfs_lookup(dir, dentry, lookup_flags); 2138 if (!res) { 2139 inode = d_inode(dentry); 2140 if ((lookup_flags & LOOKUP_DIRECTORY) && inode && 2141 !(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) 2142 res = ERR_PTR(-ENOTDIR); 2143 else if (inode && S_ISREG(inode->i_mode)) 2144 res = ERR_PTR(-EOPENSTALE); 2145 } else if (!IS_ERR(res)) { 2146 inode = d_inode(res); 2147 if ((lookup_flags & LOOKUP_DIRECTORY) && inode && 2148 !(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) { 2149 dput(res); 2150 res = ERR_PTR(-ENOTDIR); 2151 } else if (inode && S_ISREG(inode->i_mode)) { 2152 dput(res); 2153 res = ERR_PTR(-EOPENSTALE); 2154 } 2155 } 2156 if (switched) { 2157 d_lookup_done(dentry); 2158 if (!res) 2159 res = dentry; 2160 else 2161 dput(dentry); 2162 } 2163 if (IS_ERR(res)) 2164 return PTR_ERR(res); 2165 return finish_no_open(file, res); 2166 } 2167 EXPORT_SYMBOL_GPL(nfs_atomic_open); 2168 2169 static int 2170 nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry, 2171 unsigned int flags) 2172 { 2173 struct inode *inode; 2174 2175 if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY)) 2176 goto full_reval; 2177 if (d_mountpoint(dentry)) 2178 goto full_reval; 2179 2180 inode = d_inode(dentry); 2181 2182 /* We can't create new files in nfs_open_revalidate(), so we 2183 * optimize away revalidation of negative dentries. 2184 */ 2185 if (inode == NULL) 2186 goto full_reval; 2187 2188 if (nfs_verifier_is_delegated(dentry)) 2189 return nfs_lookup_revalidate_delegated(dir, dentry, inode); 2190 2191 /* NFS only supports OPEN on regular files */ 2192 if (!S_ISREG(inode->i_mode)) 2193 goto full_reval; 2194 2195 /* We cannot do exclusive creation on a positive dentry */ 2196 if (flags & (LOOKUP_EXCL | LOOKUP_REVAL)) 2197 goto reval_dentry; 2198 2199 /* Check if the directory changed */ 2200 if (!nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) 2201 goto reval_dentry; 2202 2203 /* Let f_op->open() actually open (and revalidate) the file */ 2204 return 1; 2205 reval_dentry: 2206 if (flags & LOOKUP_RCU) 2207 return -ECHILD; 2208 return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags); 2209 2210 full_reval: 2211 return nfs_do_lookup_revalidate(dir, dentry, flags); 2212 } 2213 2214 static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) 2215 { 2216 return __nfs_lookup_revalidate(dentry, flags, 2217 nfs4_do_lookup_revalidate); 2218 } 2219 2220 #endif /* CONFIG_NFSV4 */ 2221 2222 struct dentry * 2223 nfs_add_or_obtain(struct dentry *dentry, struct nfs_fh *fhandle, 2224 struct nfs_fattr *fattr) 2225 { 2226 struct dentry *parent = dget_parent(dentry); 2227 struct inode *dir = d_inode(parent); 2228 struct inode *inode; 2229 struct dentry *d; 2230 int error; 2231 2232 d_drop(dentry); 2233 2234 if (fhandle->size == 0) { 2235 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr); 2236 if (error) 2237 goto out_error; 2238 } 2239 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 2240 if (!(fattr->valid & NFS_ATTR_FATTR)) { 2241 struct nfs_server *server = NFS_SB(dentry->d_sb); 2242 error = server->nfs_client->rpc_ops->getattr(server, fhandle, 2243 fattr, NULL); 2244 if (error < 0) 2245 goto out_error; 2246 } 2247 inode = nfs_fhget(dentry->d_sb, fhandle, fattr); 2248 d = d_splice_alias(inode, dentry); 2249 out: 2250 dput(parent); 2251 return d; 2252 out_error: 2253 d = ERR_PTR(error); 2254 goto out; 2255 } 2256 EXPORT_SYMBOL_GPL(nfs_add_or_obtain); 2257 2258 /* 2259 * Code common to create, mkdir, and mknod. 2260 */ 2261 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, 2262 struct nfs_fattr *fattr) 2263 { 2264 struct dentry *d; 2265 2266 d = nfs_add_or_obtain(dentry, fhandle, fattr); 2267 if (IS_ERR(d)) 2268 return PTR_ERR(d); 2269 2270 /* Callers don't care */ 2271 dput(d); 2272 return 0; 2273 } 2274 EXPORT_SYMBOL_GPL(nfs_instantiate); 2275 2276 /* 2277 * Following a failed create operation, we drop the dentry rather 2278 * than retain a negative dentry. This avoids a problem in the event 2279 * that the operation succeeded on the server, but an error in the 2280 * reply path made it appear to have failed. 2281 */ 2282 int nfs_create(struct user_namespace *mnt_userns, struct inode *dir, 2283 struct dentry *dentry, umode_t mode, bool excl) 2284 { 2285 struct iattr attr; 2286 int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT; 2287 int error; 2288 2289 dfprintk(VFS, "NFS: create(%s/%lu), %pd\n", 2290 dir->i_sb->s_id, dir->i_ino, dentry); 2291 2292 attr.ia_mode = mode; 2293 attr.ia_valid = ATTR_MODE; 2294 2295 trace_nfs_create_enter(dir, dentry, open_flags); 2296 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags); 2297 trace_nfs_create_exit(dir, dentry, open_flags, error); 2298 if (error != 0) 2299 goto out_err; 2300 return 0; 2301 out_err: 2302 d_drop(dentry); 2303 return error; 2304 } 2305 EXPORT_SYMBOL_GPL(nfs_create); 2306 2307 /* 2308 * See comments for nfs_proc_create regarding failed operations. 2309 */ 2310 int 2311 nfs_mknod(struct user_namespace *mnt_userns, struct inode *dir, 2312 struct dentry *dentry, umode_t mode, dev_t rdev) 2313 { 2314 struct iattr attr; 2315 int status; 2316 2317 dfprintk(VFS, "NFS: mknod(%s/%lu), %pd\n", 2318 dir->i_sb->s_id, dir->i_ino, dentry); 2319 2320 attr.ia_mode = mode; 2321 attr.ia_valid = ATTR_MODE; 2322 2323 trace_nfs_mknod_enter(dir, dentry); 2324 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); 2325 trace_nfs_mknod_exit(dir, dentry, status); 2326 if (status != 0) 2327 goto out_err; 2328 return 0; 2329 out_err: 2330 d_drop(dentry); 2331 return status; 2332 } 2333 EXPORT_SYMBOL_GPL(nfs_mknod); 2334 2335 /* 2336 * See comments for nfs_proc_create regarding failed operations. 2337 */ 2338 int nfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, 2339 struct dentry *dentry, umode_t mode) 2340 { 2341 struct iattr attr; 2342 int error; 2343 2344 dfprintk(VFS, "NFS: mkdir(%s/%lu), %pd\n", 2345 dir->i_sb->s_id, dir->i_ino, dentry); 2346 2347 attr.ia_valid = ATTR_MODE; 2348 attr.ia_mode = mode | S_IFDIR; 2349 2350 trace_nfs_mkdir_enter(dir, dentry); 2351 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); 2352 trace_nfs_mkdir_exit(dir, dentry, error); 2353 if (error != 0) 2354 goto out_err; 2355 return 0; 2356 out_err: 2357 d_drop(dentry); 2358 return error; 2359 } 2360 EXPORT_SYMBOL_GPL(nfs_mkdir); 2361 2362 static void nfs_dentry_handle_enoent(struct dentry *dentry) 2363 { 2364 if (simple_positive(dentry)) 2365 d_delete(dentry); 2366 } 2367 2368 static void nfs_dentry_remove_handle_error(struct inode *dir, 2369 struct dentry *dentry, int error) 2370 { 2371 switch (error) { 2372 case -ENOENT: 2373 d_delete(dentry); 2374 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 2375 break; 2376 case 0: 2377 nfs_d_prune_case_insensitive_aliases(d_inode(dentry)); 2378 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 2379 } 2380 } 2381 2382 int nfs_rmdir(struct inode *dir, struct dentry *dentry) 2383 { 2384 int error; 2385 2386 dfprintk(VFS, "NFS: rmdir(%s/%lu), %pd\n", 2387 dir->i_sb->s_id, dir->i_ino, dentry); 2388 2389 trace_nfs_rmdir_enter(dir, dentry); 2390 if (d_really_is_positive(dentry)) { 2391 down_write(&NFS_I(d_inode(dentry))->rmdir_sem); 2392 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 2393 /* Ensure the VFS deletes this inode */ 2394 switch (error) { 2395 case 0: 2396 clear_nlink(d_inode(dentry)); 2397 break; 2398 case -ENOENT: 2399 nfs_dentry_handle_enoent(dentry); 2400 } 2401 up_write(&NFS_I(d_inode(dentry))->rmdir_sem); 2402 } else 2403 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 2404 nfs_dentry_remove_handle_error(dir, dentry, error); 2405 trace_nfs_rmdir_exit(dir, dentry, error); 2406 2407 return error; 2408 } 2409 EXPORT_SYMBOL_GPL(nfs_rmdir); 2410 2411 /* 2412 * Remove a file after making sure there are no pending writes, 2413 * and after checking that the file has only one user. 2414 * 2415 * We invalidate the attribute cache and free the inode prior to the operation 2416 * to avoid possible races if the server reuses the inode. 2417 */ 2418 static int nfs_safe_remove(struct dentry *dentry) 2419 { 2420 struct inode *dir = d_inode(dentry->d_parent); 2421 struct inode *inode = d_inode(dentry); 2422 int error = -EBUSY; 2423 2424 dfprintk(VFS, "NFS: safe_remove(%pd2)\n", dentry); 2425 2426 /* If the dentry was sillyrenamed, we simply call d_delete() */ 2427 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 2428 error = 0; 2429 goto out; 2430 } 2431 2432 trace_nfs_remove_enter(dir, dentry); 2433 if (inode != NULL) { 2434 error = NFS_PROTO(dir)->remove(dir, dentry); 2435 if (error == 0) 2436 nfs_drop_nlink(inode); 2437 } else 2438 error = NFS_PROTO(dir)->remove(dir, dentry); 2439 if (error == -ENOENT) 2440 nfs_dentry_handle_enoent(dentry); 2441 trace_nfs_remove_exit(dir, dentry, error); 2442 out: 2443 return error; 2444 } 2445 2446 /* We do silly rename. In case sillyrename() returns -EBUSY, the inode 2447 * belongs to an active ".nfs..." file and we return -EBUSY. 2448 * 2449 * If sillyrename() returns 0, we do nothing, otherwise we unlink. 2450 */ 2451 int nfs_unlink(struct inode *dir, struct dentry *dentry) 2452 { 2453 int error; 2454 int need_rehash = 0; 2455 2456 dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id, 2457 dir->i_ino, dentry); 2458 2459 trace_nfs_unlink_enter(dir, dentry); 2460 spin_lock(&dentry->d_lock); 2461 if (d_count(dentry) > 1 && !test_bit(NFS_INO_PRESERVE_UNLINKED, 2462 &NFS_I(d_inode(dentry))->flags)) { 2463 spin_unlock(&dentry->d_lock); 2464 /* Start asynchronous writeout of the inode */ 2465 write_inode_now(d_inode(dentry), 0); 2466 error = nfs_sillyrename(dir, dentry); 2467 goto out; 2468 } 2469 if (!d_unhashed(dentry)) { 2470 __d_drop(dentry); 2471 need_rehash = 1; 2472 } 2473 spin_unlock(&dentry->d_lock); 2474 error = nfs_safe_remove(dentry); 2475 nfs_dentry_remove_handle_error(dir, dentry, error); 2476 if (need_rehash) 2477 d_rehash(dentry); 2478 out: 2479 trace_nfs_unlink_exit(dir, dentry, error); 2480 return error; 2481 } 2482 EXPORT_SYMBOL_GPL(nfs_unlink); 2483 2484 /* 2485 * To create a symbolic link, most file systems instantiate a new inode, 2486 * add a page to it containing the path, then write it out to the disk 2487 * using prepare_write/commit_write. 2488 * 2489 * Unfortunately the NFS client can't create the in-core inode first 2490 * because it needs a file handle to create an in-core inode (see 2491 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the 2492 * symlink request has completed on the server. 2493 * 2494 * So instead we allocate a raw page, copy the symname into it, then do 2495 * the SYMLINK request with the page as the buffer. If it succeeds, we 2496 * now have a new file handle and can instantiate an in-core NFS inode 2497 * and move the raw page into its mapping. 2498 */ 2499 int nfs_symlink(struct user_namespace *mnt_userns, struct inode *dir, 2500 struct dentry *dentry, const char *symname) 2501 { 2502 struct page *page; 2503 char *kaddr; 2504 struct iattr attr; 2505 unsigned int pathlen = strlen(symname); 2506 int error; 2507 2508 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id, 2509 dir->i_ino, dentry, symname); 2510 2511 if (pathlen > PAGE_SIZE) 2512 return -ENAMETOOLONG; 2513 2514 attr.ia_mode = S_IFLNK | S_IRWXUGO; 2515 attr.ia_valid = ATTR_MODE; 2516 2517 page = alloc_page(GFP_USER); 2518 if (!page) 2519 return -ENOMEM; 2520 2521 kaddr = page_address(page); 2522 memcpy(kaddr, symname, pathlen); 2523 if (pathlen < PAGE_SIZE) 2524 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); 2525 2526 trace_nfs_symlink_enter(dir, dentry); 2527 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr); 2528 trace_nfs_symlink_exit(dir, dentry, error); 2529 if (error != 0) { 2530 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n", 2531 dir->i_sb->s_id, dir->i_ino, 2532 dentry, symname, error); 2533 d_drop(dentry); 2534 __free_page(page); 2535 return error; 2536 } 2537 2538 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 2539 2540 /* 2541 * No big deal if we can't add this page to the page cache here. 2542 * READLINK will get the missing page from the server if needed. 2543 */ 2544 if (!add_to_page_cache_lru(page, d_inode(dentry)->i_mapping, 0, 2545 GFP_KERNEL)) { 2546 SetPageUptodate(page); 2547 unlock_page(page); 2548 /* 2549 * add_to_page_cache_lru() grabs an extra page refcount. 2550 * Drop it here to avoid leaking this page later. 2551 */ 2552 put_page(page); 2553 } else 2554 __free_page(page); 2555 2556 return 0; 2557 } 2558 EXPORT_SYMBOL_GPL(nfs_symlink); 2559 2560 int 2561 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 2562 { 2563 struct inode *inode = d_inode(old_dentry); 2564 int error; 2565 2566 dfprintk(VFS, "NFS: link(%pd2 -> %pd2)\n", 2567 old_dentry, dentry); 2568 2569 trace_nfs_link_enter(inode, dir, dentry); 2570 d_drop(dentry); 2571 if (S_ISREG(inode->i_mode)) 2572 nfs_sync_inode(inode); 2573 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 2574 if (error == 0) { 2575 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 2576 ihold(inode); 2577 d_add(dentry, inode); 2578 } 2579 trace_nfs_link_exit(inode, dir, dentry, error); 2580 return error; 2581 } 2582 EXPORT_SYMBOL_GPL(nfs_link); 2583 2584 /* 2585 * RENAME 2586 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a 2587 * different file handle for the same inode after a rename (e.g. when 2588 * moving to a different directory). A fail-safe method to do so would 2589 * be to look up old_dir/old_name, create a link to new_dir/new_name and 2590 * rename the old file using the sillyrename stuff. This way, the original 2591 * file in old_dir will go away when the last process iput()s the inode. 2592 * 2593 * FIXED. 2594 * 2595 * It actually works quite well. One needs to have the possibility for 2596 * at least one ".nfs..." file in each directory the file ever gets 2597 * moved or linked to which happens automagically with the new 2598 * implementation that only depends on the dcache stuff instead of 2599 * using the inode layer 2600 * 2601 * Unfortunately, things are a little more complicated than indicated 2602 * above. For a cross-directory move, we want to make sure we can get 2603 * rid of the old inode after the operation. This means there must be 2604 * no pending writes (if it's a file), and the use count must be 1. 2605 * If these conditions are met, we can drop the dentries before doing 2606 * the rename. 2607 */ 2608 int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir, 2609 struct dentry *old_dentry, struct inode *new_dir, 2610 struct dentry *new_dentry, unsigned int flags) 2611 { 2612 struct inode *old_inode = d_inode(old_dentry); 2613 struct inode *new_inode = d_inode(new_dentry); 2614 struct dentry *dentry = NULL, *rehash = NULL; 2615 struct rpc_task *task; 2616 int error = -EBUSY; 2617 2618 if (flags) 2619 return -EINVAL; 2620 2621 dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n", 2622 old_dentry, new_dentry, 2623 d_count(new_dentry)); 2624 2625 trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry); 2626 /* 2627 * For non-directories, check whether the target is busy and if so, 2628 * make a copy of the dentry and then do a silly-rename. If the 2629 * silly-rename succeeds, the copied dentry is hashed and becomes 2630 * the new target. 2631 */ 2632 if (new_inode && !S_ISDIR(new_inode->i_mode)) { 2633 /* 2634 * To prevent any new references to the target during the 2635 * rename, we unhash the dentry in advance. 2636 */ 2637 if (!d_unhashed(new_dentry)) { 2638 d_drop(new_dentry); 2639 rehash = new_dentry; 2640 } 2641 2642 if (d_count(new_dentry) > 2) { 2643 int err; 2644 2645 /* copy the target dentry's name */ 2646 dentry = d_alloc(new_dentry->d_parent, 2647 &new_dentry->d_name); 2648 if (!dentry) 2649 goto out; 2650 2651 /* silly-rename the existing target ... */ 2652 err = nfs_sillyrename(new_dir, new_dentry); 2653 if (err) 2654 goto out; 2655 2656 new_dentry = dentry; 2657 rehash = NULL; 2658 new_inode = NULL; 2659 } 2660 } 2661 2662 if (S_ISREG(old_inode->i_mode)) 2663 nfs_sync_inode(old_inode); 2664 task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL); 2665 if (IS_ERR(task)) { 2666 error = PTR_ERR(task); 2667 goto out; 2668 } 2669 2670 error = rpc_wait_for_completion_task(task); 2671 if (error != 0) { 2672 ((struct nfs_renamedata *)task->tk_calldata)->cancelled = 1; 2673 /* Paired with the atomic_dec_and_test() barrier in rpc_do_put_task() */ 2674 smp_wmb(); 2675 } else 2676 error = task->tk_status; 2677 rpc_put_task(task); 2678 /* Ensure the inode attributes are revalidated */ 2679 if (error == 0) { 2680 spin_lock(&old_inode->i_lock); 2681 NFS_I(old_inode)->attr_gencount = nfs_inc_attr_generation_counter(); 2682 nfs_set_cache_invalid(old_inode, NFS_INO_INVALID_CHANGE | 2683 NFS_INO_INVALID_CTIME | 2684 NFS_INO_REVAL_FORCED); 2685 spin_unlock(&old_inode->i_lock); 2686 } 2687 out: 2688 if (rehash) 2689 d_rehash(rehash); 2690 trace_nfs_rename_exit(old_dir, old_dentry, 2691 new_dir, new_dentry, error); 2692 if (!error) { 2693 if (new_inode != NULL) 2694 nfs_drop_nlink(new_inode); 2695 /* 2696 * The d_move() should be here instead of in an async RPC completion 2697 * handler because we need the proper locks to move the dentry. If 2698 * we're interrupted by a signal, the async RPC completion handler 2699 * should mark the directories for revalidation. 2700 */ 2701 d_move(old_dentry, new_dentry); 2702 nfs_set_verifier(old_dentry, 2703 nfs_save_change_attribute(new_dir)); 2704 } else if (error == -ENOENT) 2705 nfs_dentry_handle_enoent(old_dentry); 2706 2707 /* new dentry created? */ 2708 if (dentry) 2709 dput(dentry); 2710 return error; 2711 } 2712 EXPORT_SYMBOL_GPL(nfs_rename); 2713 2714 static DEFINE_SPINLOCK(nfs_access_lru_lock); 2715 static LIST_HEAD(nfs_access_lru_list); 2716 static atomic_long_t nfs_access_nr_entries; 2717 2718 static unsigned long nfs_access_max_cachesize = 4*1024*1024; 2719 module_param(nfs_access_max_cachesize, ulong, 0644); 2720 MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length"); 2721 2722 static void nfs_access_free_entry(struct nfs_access_entry *entry) 2723 { 2724 put_group_info(entry->group_info); 2725 kfree_rcu(entry, rcu_head); 2726 smp_mb__before_atomic(); 2727 atomic_long_dec(&nfs_access_nr_entries); 2728 smp_mb__after_atomic(); 2729 } 2730 2731 static void nfs_access_free_list(struct list_head *head) 2732 { 2733 struct nfs_access_entry *cache; 2734 2735 while (!list_empty(head)) { 2736 cache = list_entry(head->next, struct nfs_access_entry, lru); 2737 list_del(&cache->lru); 2738 nfs_access_free_entry(cache); 2739 } 2740 } 2741 2742 static unsigned long 2743 nfs_do_access_cache_scan(unsigned int nr_to_scan) 2744 { 2745 LIST_HEAD(head); 2746 struct nfs_inode *nfsi, *next; 2747 struct nfs_access_entry *cache; 2748 long freed = 0; 2749 2750 spin_lock(&nfs_access_lru_lock); 2751 list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) { 2752 struct inode *inode; 2753 2754 if (nr_to_scan-- == 0) 2755 break; 2756 inode = &nfsi->vfs_inode; 2757 spin_lock(&inode->i_lock); 2758 if (list_empty(&nfsi->access_cache_entry_lru)) 2759 goto remove_lru_entry; 2760 cache = list_entry(nfsi->access_cache_entry_lru.next, 2761 struct nfs_access_entry, lru); 2762 list_move(&cache->lru, &head); 2763 rb_erase(&cache->rb_node, &nfsi->access_cache); 2764 freed++; 2765 if (!list_empty(&nfsi->access_cache_entry_lru)) 2766 list_move_tail(&nfsi->access_cache_inode_lru, 2767 &nfs_access_lru_list); 2768 else { 2769 remove_lru_entry: 2770 list_del_init(&nfsi->access_cache_inode_lru); 2771 smp_mb__before_atomic(); 2772 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); 2773 smp_mb__after_atomic(); 2774 } 2775 spin_unlock(&inode->i_lock); 2776 } 2777 spin_unlock(&nfs_access_lru_lock); 2778 nfs_access_free_list(&head); 2779 return freed; 2780 } 2781 2782 unsigned long 2783 nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc) 2784 { 2785 int nr_to_scan = sc->nr_to_scan; 2786 gfp_t gfp_mask = sc->gfp_mask; 2787 2788 if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL) 2789 return SHRINK_STOP; 2790 return nfs_do_access_cache_scan(nr_to_scan); 2791 } 2792 2793 2794 unsigned long 2795 nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc) 2796 { 2797 return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries)); 2798 } 2799 2800 static void 2801 nfs_access_cache_enforce_limit(void) 2802 { 2803 long nr_entries = atomic_long_read(&nfs_access_nr_entries); 2804 unsigned long diff; 2805 unsigned int nr_to_scan; 2806 2807 if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize) 2808 return; 2809 nr_to_scan = 100; 2810 diff = nr_entries - nfs_access_max_cachesize; 2811 if (diff < nr_to_scan) 2812 nr_to_scan = diff; 2813 nfs_do_access_cache_scan(nr_to_scan); 2814 } 2815 2816 static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head) 2817 { 2818 struct rb_root *root_node = &nfsi->access_cache; 2819 struct rb_node *n; 2820 struct nfs_access_entry *entry; 2821 2822 /* Unhook entries from the cache */ 2823 while ((n = rb_first(root_node)) != NULL) { 2824 entry = rb_entry(n, struct nfs_access_entry, rb_node); 2825 rb_erase(n, root_node); 2826 list_move(&entry->lru, head); 2827 } 2828 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; 2829 } 2830 2831 void nfs_access_zap_cache(struct inode *inode) 2832 { 2833 LIST_HEAD(head); 2834 2835 if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0) 2836 return; 2837 /* Remove from global LRU init */ 2838 spin_lock(&nfs_access_lru_lock); 2839 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2840 list_del_init(&NFS_I(inode)->access_cache_inode_lru); 2841 2842 spin_lock(&inode->i_lock); 2843 __nfs_access_zap_cache(NFS_I(inode), &head); 2844 spin_unlock(&inode->i_lock); 2845 spin_unlock(&nfs_access_lru_lock); 2846 nfs_access_free_list(&head); 2847 } 2848 EXPORT_SYMBOL_GPL(nfs_access_zap_cache); 2849 2850 static int access_cmp(const struct cred *a, const struct nfs_access_entry *b) 2851 { 2852 struct group_info *ga, *gb; 2853 int g; 2854 2855 if (uid_lt(a->fsuid, b->fsuid)) 2856 return -1; 2857 if (uid_gt(a->fsuid, b->fsuid)) 2858 return 1; 2859 2860 if (gid_lt(a->fsgid, b->fsgid)) 2861 return -1; 2862 if (gid_gt(a->fsgid, b->fsgid)) 2863 return 1; 2864 2865 ga = a->group_info; 2866 gb = b->group_info; 2867 if (ga == gb) 2868 return 0; 2869 if (ga == NULL) 2870 return -1; 2871 if (gb == NULL) 2872 return 1; 2873 if (ga->ngroups < gb->ngroups) 2874 return -1; 2875 if (ga->ngroups > gb->ngroups) 2876 return 1; 2877 2878 for (g = 0; g < ga->ngroups; g++) { 2879 if (gid_lt(ga->gid[g], gb->gid[g])) 2880 return -1; 2881 if (gid_gt(ga->gid[g], gb->gid[g])) 2882 return 1; 2883 } 2884 return 0; 2885 } 2886 2887 static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, const struct cred *cred) 2888 { 2889 struct rb_node *n = NFS_I(inode)->access_cache.rb_node; 2890 2891 while (n != NULL) { 2892 struct nfs_access_entry *entry = 2893 rb_entry(n, struct nfs_access_entry, rb_node); 2894 int cmp = access_cmp(cred, entry); 2895 2896 if (cmp < 0) 2897 n = n->rb_left; 2898 else if (cmp > 0) 2899 n = n->rb_right; 2900 else 2901 return entry; 2902 } 2903 return NULL; 2904 } 2905 2906 static int nfs_access_get_cached_locked(struct inode *inode, const struct cred *cred, u32 *mask, bool may_block) 2907 { 2908 struct nfs_inode *nfsi = NFS_I(inode); 2909 struct nfs_access_entry *cache; 2910 bool retry = true; 2911 int err; 2912 2913 spin_lock(&inode->i_lock); 2914 for(;;) { 2915 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2916 goto out_zap; 2917 cache = nfs_access_search_rbtree(inode, cred); 2918 err = -ENOENT; 2919 if (cache == NULL) 2920 goto out; 2921 /* Found an entry, is our attribute cache valid? */ 2922 if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) 2923 break; 2924 if (!retry) 2925 break; 2926 err = -ECHILD; 2927 if (!may_block) 2928 goto out; 2929 spin_unlock(&inode->i_lock); 2930 err = __nfs_revalidate_inode(NFS_SERVER(inode), inode); 2931 if (err) 2932 return err; 2933 spin_lock(&inode->i_lock); 2934 retry = false; 2935 } 2936 *mask = cache->mask; 2937 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru); 2938 err = 0; 2939 out: 2940 spin_unlock(&inode->i_lock); 2941 return err; 2942 out_zap: 2943 spin_unlock(&inode->i_lock); 2944 nfs_access_zap_cache(inode); 2945 return -ENOENT; 2946 } 2947 2948 static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cred, u32 *mask) 2949 { 2950 /* Only check the most recently returned cache entry, 2951 * but do it without locking. 2952 */ 2953 struct nfs_inode *nfsi = NFS_I(inode); 2954 struct nfs_access_entry *cache; 2955 int err = -ECHILD; 2956 struct list_head *lh; 2957 2958 rcu_read_lock(); 2959 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2960 goto out; 2961 lh = rcu_dereference(list_tail_rcu(&nfsi->access_cache_entry_lru)); 2962 cache = list_entry(lh, struct nfs_access_entry, lru); 2963 if (lh == &nfsi->access_cache_entry_lru || 2964 access_cmp(cred, cache) != 0) 2965 cache = NULL; 2966 if (cache == NULL) 2967 goto out; 2968 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) 2969 goto out; 2970 *mask = cache->mask; 2971 err = 0; 2972 out: 2973 rcu_read_unlock(); 2974 return err; 2975 } 2976 2977 int nfs_access_get_cached(struct inode *inode, const struct cred *cred, 2978 u32 *mask, bool may_block) 2979 { 2980 int status; 2981 2982 status = nfs_access_get_cached_rcu(inode, cred, mask); 2983 if (status != 0) 2984 status = nfs_access_get_cached_locked(inode, cred, mask, 2985 may_block); 2986 2987 return status; 2988 } 2989 EXPORT_SYMBOL_GPL(nfs_access_get_cached); 2990 2991 static void nfs_access_add_rbtree(struct inode *inode, 2992 struct nfs_access_entry *set, 2993 const struct cred *cred) 2994 { 2995 struct nfs_inode *nfsi = NFS_I(inode); 2996 struct rb_root *root_node = &nfsi->access_cache; 2997 struct rb_node **p = &root_node->rb_node; 2998 struct rb_node *parent = NULL; 2999 struct nfs_access_entry *entry; 3000 int cmp; 3001 3002 spin_lock(&inode->i_lock); 3003 while (*p != NULL) { 3004 parent = *p; 3005 entry = rb_entry(parent, struct nfs_access_entry, rb_node); 3006 cmp = access_cmp(cred, entry); 3007 3008 if (cmp < 0) 3009 p = &parent->rb_left; 3010 else if (cmp > 0) 3011 p = &parent->rb_right; 3012 else 3013 goto found; 3014 } 3015 rb_link_node(&set->rb_node, parent, p); 3016 rb_insert_color(&set->rb_node, root_node); 3017 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 3018 spin_unlock(&inode->i_lock); 3019 return; 3020 found: 3021 rb_replace_node(parent, &set->rb_node, root_node); 3022 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 3023 list_del(&entry->lru); 3024 spin_unlock(&inode->i_lock); 3025 nfs_access_free_entry(entry); 3026 } 3027 3028 void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set, 3029 const struct cred *cred) 3030 { 3031 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); 3032 if (cache == NULL) 3033 return; 3034 RB_CLEAR_NODE(&cache->rb_node); 3035 cache->fsuid = cred->fsuid; 3036 cache->fsgid = cred->fsgid; 3037 cache->group_info = get_group_info(cred->group_info); 3038 cache->mask = set->mask; 3039 3040 /* The above field assignments must be visible 3041 * before this item appears on the lru. We cannot easily 3042 * use rcu_assign_pointer, so just force the memory barrier. 3043 */ 3044 smp_wmb(); 3045 nfs_access_add_rbtree(inode, cache, cred); 3046 3047 /* Update accounting */ 3048 smp_mb__before_atomic(); 3049 atomic_long_inc(&nfs_access_nr_entries); 3050 smp_mb__after_atomic(); 3051 3052 /* Add inode to global LRU list */ 3053 if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) { 3054 spin_lock(&nfs_access_lru_lock); 3055 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 3056 list_add_tail(&NFS_I(inode)->access_cache_inode_lru, 3057 &nfs_access_lru_list); 3058 spin_unlock(&nfs_access_lru_lock); 3059 } 3060 nfs_access_cache_enforce_limit(); 3061 } 3062 EXPORT_SYMBOL_GPL(nfs_access_add_cache); 3063 3064 #define NFS_MAY_READ (NFS_ACCESS_READ) 3065 #define NFS_MAY_WRITE (NFS_ACCESS_MODIFY | \ 3066 NFS_ACCESS_EXTEND | \ 3067 NFS_ACCESS_DELETE) 3068 #define NFS_FILE_MAY_WRITE (NFS_ACCESS_MODIFY | \ 3069 NFS_ACCESS_EXTEND) 3070 #define NFS_DIR_MAY_WRITE NFS_MAY_WRITE 3071 #define NFS_MAY_LOOKUP (NFS_ACCESS_LOOKUP) 3072 #define NFS_MAY_EXECUTE (NFS_ACCESS_EXECUTE) 3073 static int 3074 nfs_access_calc_mask(u32 access_result, umode_t umode) 3075 { 3076 int mask = 0; 3077 3078 if (access_result & NFS_MAY_READ) 3079 mask |= MAY_READ; 3080 if (S_ISDIR(umode)) { 3081 if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE) 3082 mask |= MAY_WRITE; 3083 if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP) 3084 mask |= MAY_EXEC; 3085 } else if (S_ISREG(umode)) { 3086 if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE) 3087 mask |= MAY_WRITE; 3088 if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE) 3089 mask |= MAY_EXEC; 3090 } else if (access_result & NFS_MAY_WRITE) 3091 mask |= MAY_WRITE; 3092 return mask; 3093 } 3094 3095 void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result) 3096 { 3097 entry->mask = access_result; 3098 } 3099 EXPORT_SYMBOL_GPL(nfs_access_set_mask); 3100 3101 static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask) 3102 { 3103 struct nfs_access_entry cache; 3104 bool may_block = (mask & MAY_NOT_BLOCK) == 0; 3105 int cache_mask = -1; 3106 int status; 3107 3108 trace_nfs_access_enter(inode); 3109 3110 status = nfs_access_get_cached(inode, cred, &cache.mask, may_block); 3111 if (status == 0) 3112 goto out_cached; 3113 3114 status = -ECHILD; 3115 if (!may_block) 3116 goto out; 3117 3118 /* 3119 * Determine which access bits we want to ask for... 3120 */ 3121 cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND | 3122 nfs_access_xattr_mask(NFS_SERVER(inode)); 3123 if (S_ISDIR(inode->i_mode)) 3124 cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP; 3125 else 3126 cache.mask |= NFS_ACCESS_EXECUTE; 3127 status = NFS_PROTO(inode)->access(inode, &cache, cred); 3128 if (status != 0) { 3129 if (status == -ESTALE) { 3130 if (!S_ISDIR(inode->i_mode)) 3131 nfs_set_inode_stale(inode); 3132 else 3133 nfs_zap_caches(inode); 3134 } 3135 goto out; 3136 } 3137 nfs_access_add_cache(inode, &cache, cred); 3138 out_cached: 3139 cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode); 3140 if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0) 3141 status = -EACCES; 3142 out: 3143 trace_nfs_access_exit(inode, mask, cache_mask, status); 3144 return status; 3145 } 3146 3147 static int nfs_open_permission_mask(int openflags) 3148 { 3149 int mask = 0; 3150 3151 if (openflags & __FMODE_EXEC) { 3152 /* ONLY check exec rights */ 3153 mask = MAY_EXEC; 3154 } else { 3155 if ((openflags & O_ACCMODE) != O_WRONLY) 3156 mask |= MAY_READ; 3157 if ((openflags & O_ACCMODE) != O_RDONLY) 3158 mask |= MAY_WRITE; 3159 } 3160 3161 return mask; 3162 } 3163 3164 int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags) 3165 { 3166 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); 3167 } 3168 EXPORT_SYMBOL_GPL(nfs_may_open); 3169 3170 static int nfs_execute_ok(struct inode *inode, int mask) 3171 { 3172 struct nfs_server *server = NFS_SERVER(inode); 3173 int ret = 0; 3174 3175 if (S_ISDIR(inode->i_mode)) 3176 return 0; 3177 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_MODE)) { 3178 if (mask & MAY_NOT_BLOCK) 3179 return -ECHILD; 3180 ret = __nfs_revalidate_inode(server, inode); 3181 } 3182 if (ret == 0 && !execute_ok(inode)) 3183 ret = -EACCES; 3184 return ret; 3185 } 3186 3187 int nfs_permission(struct user_namespace *mnt_userns, 3188 struct inode *inode, 3189 int mask) 3190 { 3191 const struct cred *cred = current_cred(); 3192 int res = 0; 3193 3194 nfs_inc_stats(inode, NFSIOS_VFSACCESS); 3195 3196 if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) 3197 goto out; 3198 /* Is this sys_access() ? */ 3199 if (mask & (MAY_ACCESS | MAY_CHDIR)) 3200 goto force_lookup; 3201 3202 switch (inode->i_mode & S_IFMT) { 3203 case S_IFLNK: 3204 goto out; 3205 case S_IFREG: 3206 if ((mask & MAY_OPEN) && 3207 nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)) 3208 return 0; 3209 break; 3210 case S_IFDIR: 3211 /* 3212 * Optimize away all write operations, since the server 3213 * will check permissions when we perform the op. 3214 */ 3215 if ((mask & MAY_WRITE) && !(mask & MAY_READ)) 3216 goto out; 3217 } 3218 3219 force_lookup: 3220 if (!NFS_PROTO(inode)->access) 3221 goto out_notsup; 3222 3223 res = nfs_do_access(inode, cred, mask); 3224 out: 3225 if (!res && (mask & MAY_EXEC)) 3226 res = nfs_execute_ok(inode, mask); 3227 3228 dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n", 3229 inode->i_sb->s_id, inode->i_ino, mask, res); 3230 return res; 3231 out_notsup: 3232 if (mask & MAY_NOT_BLOCK) 3233 return -ECHILD; 3234 3235 res = nfs_revalidate_inode(inode, NFS_INO_INVALID_MODE | 3236 NFS_INO_INVALID_OTHER); 3237 if (res == 0) 3238 res = generic_permission(&init_user_ns, inode, mask); 3239 goto out; 3240 } 3241 EXPORT_SYMBOL_GPL(nfs_permission); 3242