1 /* 2 * linux/fs/nfs/dir.c 3 * 4 * Copyright (C) 1992 Rick Sladkey 5 * 6 * nfs directory handling functions 7 * 8 * 10 Apr 1996 Added silly rename for unlink --okir 9 * 28 Sep 1996 Improved directory cache --okir 10 * 23 Aug 1997 Claus Heine claus@momo.math.rwth-aachen.de 11 * Re-implemented silly rename for unlink, newly implemented 12 * silly rename for nfs_rename() following the suggestions 13 * of Olaf Kirch (okir) found in this file. 14 * Following Linus comments on my original hack, this version 15 * depends only on the dcache stuff and doesn't touch the inode 16 * layer (iput() and friends). 17 * 6 Jun 1999 Cache readdir lookups in the page cache. -DaveM 18 */ 19 20 #include <linux/module.h> 21 #include <linux/time.h> 22 #include <linux/errno.h> 23 #include <linux/stat.h> 24 #include <linux/fcntl.h> 25 #include <linux/string.h> 26 #include <linux/kernel.h> 27 #include <linux/slab.h> 28 #include <linux/mm.h> 29 #include <linux/sunrpc/clnt.h> 30 #include <linux/nfs_fs.h> 31 #include <linux/nfs_mount.h> 32 #include <linux/pagemap.h> 33 #include <linux/pagevec.h> 34 #include <linux/namei.h> 35 #include <linux/mount.h> 36 #include <linux/swap.h> 37 #include <linux/sched.h> 38 #include <linux/kmemleak.h> 39 #include <linux/xattr.h> 40 41 #include "delegation.h" 42 #include "iostat.h" 43 #include "internal.h" 44 #include "fscache.h" 45 46 #include "nfstrace.h" 47 48 /* #define NFS_DEBUG_VERBOSE 1 */ 49 50 static int nfs_opendir(struct inode *, struct file *); 51 static int nfs_closedir(struct inode *, struct file *); 52 static int nfs_readdir(struct file *, struct dir_context *); 53 static int nfs_fsync_dir(struct file *, loff_t, loff_t, int); 54 static loff_t nfs_llseek_dir(struct file *, loff_t, int); 55 static void nfs_readdir_clear_array(struct page*); 56 57 const struct file_operations nfs_dir_operations = { 58 .llseek = nfs_llseek_dir, 59 .read = generic_read_dir, 60 .iterate = nfs_readdir, 61 .open = nfs_opendir, 62 .release = nfs_closedir, 63 .fsync = nfs_fsync_dir, 64 }; 65 66 const struct address_space_operations nfs_dir_aops = { 67 .freepage = nfs_readdir_clear_array, 68 }; 69 70 static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir, struct rpc_cred *cred) 71 { 72 struct nfs_inode *nfsi = NFS_I(dir); 73 struct nfs_open_dir_context *ctx; 74 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); 75 if (ctx != NULL) { 76 ctx->duped = 0; 77 ctx->attr_gencount = nfsi->attr_gencount; 78 ctx->dir_cookie = 0; 79 ctx->dup_cookie = 0; 80 ctx->cred = get_rpccred(cred); 81 spin_lock(&dir->i_lock); 82 list_add(&ctx->list, &nfsi->open_files); 83 spin_unlock(&dir->i_lock); 84 return ctx; 85 } 86 return ERR_PTR(-ENOMEM); 87 } 88 89 static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx) 90 { 91 spin_lock(&dir->i_lock); 92 list_del(&ctx->list); 93 spin_unlock(&dir->i_lock); 94 put_rpccred(ctx->cred); 95 kfree(ctx); 96 } 97 98 /* 99 * Open file 100 */ 101 static int 102 nfs_opendir(struct inode *inode, struct file *filp) 103 { 104 int res = 0; 105 struct nfs_open_dir_context *ctx; 106 struct rpc_cred *cred; 107 108 dfprintk(FILE, "NFS: open dir(%pD2)\n", filp); 109 110 nfs_inc_stats(inode, NFSIOS_VFSOPEN); 111 112 cred = rpc_lookup_cred(); 113 if (IS_ERR(cred)) 114 return PTR_ERR(cred); 115 ctx = alloc_nfs_open_dir_context(inode, cred); 116 if (IS_ERR(ctx)) { 117 res = PTR_ERR(ctx); 118 goto out; 119 } 120 filp->private_data = ctx; 121 if (filp->f_path.dentry == filp->f_path.mnt->mnt_root) { 122 /* This is a mountpoint, so d_revalidate will never 123 * have been called, so we need to refresh the 124 * inode (for close-open consistency) ourselves. 125 */ 126 __nfs_revalidate_inode(NFS_SERVER(inode), inode); 127 } 128 out: 129 put_rpccred(cred); 130 return res; 131 } 132 133 static int 134 nfs_closedir(struct inode *inode, struct file *filp) 135 { 136 put_nfs_open_dir_context(file_inode(filp), filp->private_data); 137 return 0; 138 } 139 140 struct nfs_cache_array_entry { 141 u64 cookie; 142 u64 ino; 143 struct qstr string; 144 unsigned char d_type; 145 }; 146 147 struct nfs_cache_array { 148 int size; 149 int eof_index; 150 u64 last_cookie; 151 struct nfs_cache_array_entry array[0]; 152 }; 153 154 typedef int (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, bool); 155 typedef struct { 156 struct file *file; 157 struct page *page; 158 struct dir_context *ctx; 159 unsigned long page_index; 160 u64 *dir_cookie; 161 u64 last_cookie; 162 loff_t current_index; 163 decode_dirent_t decode; 164 165 unsigned long timestamp; 166 unsigned long gencount; 167 unsigned int cache_entry_index; 168 bool plus; 169 bool eof; 170 } nfs_readdir_descriptor_t; 171 172 /* 173 * we are freeing strings created by nfs_add_to_readdir_array() 174 */ 175 static 176 void nfs_readdir_clear_array(struct page *page) 177 { 178 struct nfs_cache_array *array; 179 int i; 180 181 array = kmap_atomic(page); 182 for (i = 0; i < array->size; i++) 183 kfree(array->array[i].string.name); 184 kunmap_atomic(array); 185 } 186 187 /* 188 * the caller is responsible for freeing qstr.name 189 * when called by nfs_readdir_add_to_array, the strings will be freed in 190 * nfs_clear_readdir_array() 191 */ 192 static 193 int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int len) 194 { 195 string->len = len; 196 string->name = kmemdup(name, len, GFP_KERNEL); 197 if (string->name == NULL) 198 return -ENOMEM; 199 /* 200 * Avoid a kmemleak false positive. The pointer to the name is stored 201 * in a page cache page which kmemleak does not scan. 202 */ 203 kmemleak_not_leak(string->name); 204 string->hash = full_name_hash(NULL, name, len); 205 return 0; 206 } 207 208 static 209 int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page) 210 { 211 struct nfs_cache_array *array = kmap(page); 212 struct nfs_cache_array_entry *cache_entry; 213 int ret; 214 215 cache_entry = &array->array[array->size]; 216 217 /* Check that this entry lies within the page bounds */ 218 ret = -ENOSPC; 219 if ((char *)&cache_entry[1] - (char *)page_address(page) > PAGE_SIZE) 220 goto out; 221 222 cache_entry->cookie = entry->prev_cookie; 223 cache_entry->ino = entry->ino; 224 cache_entry->d_type = entry->d_type; 225 ret = nfs_readdir_make_qstr(&cache_entry->string, entry->name, entry->len); 226 if (ret) 227 goto out; 228 array->last_cookie = entry->cookie; 229 array->size++; 230 if (entry->eof != 0) 231 array->eof_index = array->size; 232 out: 233 kunmap(page); 234 return ret; 235 } 236 237 static 238 int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc) 239 { 240 loff_t diff = desc->ctx->pos - desc->current_index; 241 unsigned int index; 242 243 if (diff < 0) 244 goto out_eof; 245 if (diff >= array->size) { 246 if (array->eof_index >= 0) 247 goto out_eof; 248 return -EAGAIN; 249 } 250 251 index = (unsigned int)diff; 252 *desc->dir_cookie = array->array[index].cookie; 253 desc->cache_entry_index = index; 254 return 0; 255 out_eof: 256 desc->eof = 1; 257 return -EBADCOOKIE; 258 } 259 260 static bool 261 nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi) 262 { 263 if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA)) 264 return false; 265 smp_rmb(); 266 return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags); 267 } 268 269 static 270 int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc) 271 { 272 int i; 273 loff_t new_pos; 274 int status = -EAGAIN; 275 276 for (i = 0; i < array->size; i++) { 277 if (array->array[i].cookie == *desc->dir_cookie) { 278 struct nfs_inode *nfsi = NFS_I(file_inode(desc->file)); 279 struct nfs_open_dir_context *ctx = desc->file->private_data; 280 281 new_pos = desc->current_index + i; 282 if (ctx->attr_gencount != nfsi->attr_gencount || 283 !nfs_readdir_inode_mapping_valid(nfsi)) { 284 ctx->duped = 0; 285 ctx->attr_gencount = nfsi->attr_gencount; 286 } else if (new_pos < desc->ctx->pos) { 287 if (ctx->duped > 0 288 && ctx->dup_cookie == *desc->dir_cookie) { 289 if (printk_ratelimit()) { 290 pr_notice("NFS: directory %pD2 contains a readdir loop." 291 "Please contact your server vendor. " 292 "The file: %.*s has duplicate cookie %llu\n", 293 desc->file, array->array[i].string.len, 294 array->array[i].string.name, *desc->dir_cookie); 295 } 296 status = -ELOOP; 297 goto out; 298 } 299 ctx->dup_cookie = *desc->dir_cookie; 300 ctx->duped = -1; 301 } 302 desc->ctx->pos = new_pos; 303 desc->cache_entry_index = i; 304 return 0; 305 } 306 } 307 if (array->eof_index >= 0) { 308 status = -EBADCOOKIE; 309 if (*desc->dir_cookie == array->last_cookie) 310 desc->eof = 1; 311 } 312 out: 313 return status; 314 } 315 316 static 317 int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc) 318 { 319 struct nfs_cache_array *array; 320 int status; 321 322 array = kmap(desc->page); 323 324 if (*desc->dir_cookie == 0) 325 status = nfs_readdir_search_for_pos(array, desc); 326 else 327 status = nfs_readdir_search_for_cookie(array, desc); 328 329 if (status == -EAGAIN) { 330 desc->last_cookie = array->last_cookie; 331 desc->current_index += array->size; 332 desc->page_index++; 333 } 334 kunmap(desc->page); 335 return status; 336 } 337 338 /* Fill a page with xdr information before transferring to the cache page */ 339 static 340 int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc, 341 struct nfs_entry *entry, struct file *file, struct inode *inode) 342 { 343 struct nfs_open_dir_context *ctx = file->private_data; 344 struct rpc_cred *cred = ctx->cred; 345 unsigned long timestamp, gencount; 346 int error; 347 348 again: 349 timestamp = jiffies; 350 gencount = nfs_inc_attr_generation_counter(); 351 error = NFS_PROTO(inode)->readdir(file_dentry(file), cred, entry->cookie, pages, 352 NFS_SERVER(inode)->dtsize, desc->plus); 353 if (error < 0) { 354 /* We requested READDIRPLUS, but the server doesn't grok it */ 355 if (error == -ENOTSUPP && desc->plus) { 356 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; 357 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 358 desc->plus = false; 359 goto again; 360 } 361 goto error; 362 } 363 desc->timestamp = timestamp; 364 desc->gencount = gencount; 365 error: 366 return error; 367 } 368 369 static int xdr_decode(nfs_readdir_descriptor_t *desc, 370 struct nfs_entry *entry, struct xdr_stream *xdr) 371 { 372 int error; 373 374 error = desc->decode(xdr, entry, desc->plus); 375 if (error) 376 return error; 377 entry->fattr->time_start = desc->timestamp; 378 entry->fattr->gencount = desc->gencount; 379 return 0; 380 } 381 382 /* Match file and dirent using either filehandle or fileid 383 * Note: caller is responsible for checking the fsid 384 */ 385 static 386 int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) 387 { 388 struct inode *inode; 389 struct nfs_inode *nfsi; 390 391 if (d_really_is_negative(dentry)) 392 return 0; 393 394 inode = d_inode(dentry); 395 if (is_bad_inode(inode) || NFS_STALE(inode)) 396 return 0; 397 398 nfsi = NFS_I(inode); 399 if (entry->fattr->fileid != nfsi->fileid) 400 return 0; 401 if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0) 402 return 0; 403 return 1; 404 } 405 406 static 407 bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx) 408 { 409 if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS)) 410 return false; 411 if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags)) 412 return true; 413 if (ctx->pos == 0) 414 return true; 415 return false; 416 } 417 418 /* 419 * This function is called by the lookup and getattr code to request the 420 * use of readdirplus to accelerate any future lookups in the same 421 * directory. 422 */ 423 void nfs_advise_use_readdirplus(struct inode *dir) 424 { 425 struct nfs_inode *nfsi = NFS_I(dir); 426 427 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && 428 !list_empty(&nfsi->open_files)) 429 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); 430 } 431 432 /* 433 * This function is mainly for use by nfs_getattr(). 434 * 435 * If this is an 'ls -l', we want to force use of readdirplus. 436 * Do this by checking if there is an active file descriptor 437 * and calling nfs_advise_use_readdirplus, then forcing a 438 * cache flush. 439 */ 440 void nfs_force_use_readdirplus(struct inode *dir) 441 { 442 struct nfs_inode *nfsi = NFS_I(dir); 443 444 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && 445 !list_empty(&nfsi->open_files)) { 446 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); 447 invalidate_mapping_pages(dir->i_mapping, 0, -1); 448 } 449 } 450 451 static 452 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry) 453 { 454 struct qstr filename = QSTR_INIT(entry->name, entry->len); 455 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 456 struct dentry *dentry; 457 struct dentry *alias; 458 struct inode *dir = d_inode(parent); 459 struct inode *inode; 460 int status; 461 462 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID)) 463 return; 464 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID)) 465 return; 466 if (filename.len == 0) 467 return; 468 /* Validate that the name doesn't contain any illegal '\0' */ 469 if (strnlen(filename.name, filename.len) != filename.len) 470 return; 471 /* ...or '/' */ 472 if (strnchr(filename.name, filename.len, '/')) 473 return; 474 if (filename.name[0] == '.') { 475 if (filename.len == 1) 476 return; 477 if (filename.len == 2 && filename.name[1] == '.') 478 return; 479 } 480 filename.hash = full_name_hash(parent, filename.name, filename.len); 481 482 dentry = d_lookup(parent, &filename); 483 again: 484 if (!dentry) { 485 dentry = d_alloc_parallel(parent, &filename, &wq); 486 if (IS_ERR(dentry)) 487 return; 488 } 489 if (!d_in_lookup(dentry)) { 490 /* Is there a mountpoint here? If so, just exit */ 491 if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid, 492 &entry->fattr->fsid)) 493 goto out; 494 if (nfs_same_file(dentry, entry)) { 495 if (!entry->fh->size) 496 goto out; 497 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 498 status = nfs_refresh_inode(d_inode(dentry), entry->fattr); 499 if (!status) 500 nfs_setsecurity(d_inode(dentry), entry->fattr, entry->label); 501 goto out; 502 } else { 503 d_invalidate(dentry); 504 dput(dentry); 505 dentry = NULL; 506 goto again; 507 } 508 } 509 if (!entry->fh->size) { 510 d_lookup_done(dentry); 511 goto out; 512 } 513 514 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label); 515 alias = d_splice_alias(inode, dentry); 516 d_lookup_done(dentry); 517 if (alias) { 518 if (IS_ERR(alias)) 519 goto out; 520 dput(dentry); 521 dentry = alias; 522 } 523 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 524 out: 525 dput(dentry); 526 } 527 528 /* Perform conversion from xdr to cache array */ 529 static 530 int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, 531 struct page **xdr_pages, struct page *page, unsigned int buflen) 532 { 533 struct xdr_stream stream; 534 struct xdr_buf buf; 535 struct page *scratch; 536 struct nfs_cache_array *array; 537 unsigned int count = 0; 538 int status; 539 540 scratch = alloc_page(GFP_KERNEL); 541 if (scratch == NULL) 542 return -ENOMEM; 543 544 if (buflen == 0) 545 goto out_nopages; 546 547 xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen); 548 xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE); 549 550 do { 551 status = xdr_decode(desc, entry, &stream); 552 if (status != 0) { 553 if (status == -EAGAIN) 554 status = 0; 555 break; 556 } 557 558 count++; 559 560 if (desc->plus) 561 nfs_prime_dcache(file_dentry(desc->file), entry); 562 563 status = nfs_readdir_add_to_array(entry, page); 564 if (status != 0) 565 break; 566 } while (!entry->eof); 567 568 out_nopages: 569 if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) { 570 array = kmap(page); 571 array->eof_index = array->size; 572 status = 0; 573 kunmap(page); 574 } 575 576 put_page(scratch); 577 return status; 578 } 579 580 static 581 void nfs_readdir_free_pages(struct page **pages, unsigned int npages) 582 { 583 unsigned int i; 584 for (i = 0; i < npages; i++) 585 put_page(pages[i]); 586 } 587 588 /* 589 * nfs_readdir_large_page will allocate pages that must be freed with a call 590 * to nfs_readdir_free_pagearray 591 */ 592 static 593 int nfs_readdir_alloc_pages(struct page **pages, unsigned int npages) 594 { 595 unsigned int i; 596 597 for (i = 0; i < npages; i++) { 598 struct page *page = alloc_page(GFP_KERNEL); 599 if (page == NULL) 600 goto out_freepages; 601 pages[i] = page; 602 } 603 return 0; 604 605 out_freepages: 606 nfs_readdir_free_pages(pages, i); 607 return -ENOMEM; 608 } 609 610 static 611 int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode) 612 { 613 struct page *pages[NFS_MAX_READDIR_PAGES]; 614 struct nfs_entry entry; 615 struct file *file = desc->file; 616 struct nfs_cache_array *array; 617 int status = -ENOMEM; 618 unsigned int array_size = ARRAY_SIZE(pages); 619 620 entry.prev_cookie = 0; 621 entry.cookie = desc->last_cookie; 622 entry.eof = 0; 623 entry.fh = nfs_alloc_fhandle(); 624 entry.fattr = nfs_alloc_fattr(); 625 entry.server = NFS_SERVER(inode); 626 if (entry.fh == NULL || entry.fattr == NULL) 627 goto out; 628 629 entry.label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT); 630 if (IS_ERR(entry.label)) { 631 status = PTR_ERR(entry.label); 632 goto out; 633 } 634 635 array = kmap(page); 636 memset(array, 0, sizeof(struct nfs_cache_array)); 637 array->eof_index = -1; 638 639 status = nfs_readdir_alloc_pages(pages, array_size); 640 if (status < 0) 641 goto out_release_array; 642 do { 643 unsigned int pglen; 644 status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode); 645 646 if (status < 0) 647 break; 648 pglen = status; 649 status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen); 650 if (status < 0) { 651 if (status == -ENOSPC) 652 status = 0; 653 break; 654 } 655 } while (array->eof_index < 0); 656 657 nfs_readdir_free_pages(pages, array_size); 658 out_release_array: 659 kunmap(page); 660 nfs4_label_free(entry.label); 661 out: 662 nfs_free_fattr(entry.fattr); 663 nfs_free_fhandle(entry.fh); 664 return status; 665 } 666 667 /* 668 * Now we cache directories properly, by converting xdr information 669 * to an array that can be used for lookups later. This results in 670 * fewer cache pages, since we can store more information on each page. 671 * We only need to convert from xdr once so future lookups are much simpler 672 */ 673 static 674 int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page) 675 { 676 struct inode *inode = file_inode(desc->file); 677 int ret; 678 679 ret = nfs_readdir_xdr_to_array(desc, page, inode); 680 if (ret < 0) 681 goto error; 682 SetPageUptodate(page); 683 684 if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) { 685 /* Should never happen */ 686 nfs_zap_mapping(inode, inode->i_mapping); 687 } 688 unlock_page(page); 689 return 0; 690 error: 691 unlock_page(page); 692 return ret; 693 } 694 695 static 696 void cache_page_release(nfs_readdir_descriptor_t *desc) 697 { 698 if (!desc->page->mapping) 699 nfs_readdir_clear_array(desc->page); 700 put_page(desc->page); 701 desc->page = NULL; 702 } 703 704 static 705 struct page *get_cache_page(nfs_readdir_descriptor_t *desc) 706 { 707 return read_cache_page(desc->file->f_mapping, 708 desc->page_index, (filler_t *)nfs_readdir_filler, desc); 709 } 710 711 /* 712 * Returns 0 if desc->dir_cookie was found on page desc->page_index 713 */ 714 static 715 int find_cache_page(nfs_readdir_descriptor_t *desc) 716 { 717 int res; 718 719 desc->page = get_cache_page(desc); 720 if (IS_ERR(desc->page)) 721 return PTR_ERR(desc->page); 722 723 res = nfs_readdir_search_array(desc); 724 if (res != 0) 725 cache_page_release(desc); 726 return res; 727 } 728 729 /* Search for desc->dir_cookie from the beginning of the page cache */ 730 static inline 731 int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) 732 { 733 int res; 734 735 if (desc->page_index == 0) { 736 desc->current_index = 0; 737 desc->last_cookie = 0; 738 } 739 do { 740 res = find_cache_page(desc); 741 } while (res == -EAGAIN); 742 return res; 743 } 744 745 /* 746 * Once we've found the start of the dirent within a page: fill 'er up... 747 */ 748 static 749 int nfs_do_filldir(nfs_readdir_descriptor_t *desc) 750 { 751 struct file *file = desc->file; 752 int i = 0; 753 int res = 0; 754 struct nfs_cache_array *array = NULL; 755 struct nfs_open_dir_context *ctx = file->private_data; 756 757 array = kmap(desc->page); 758 for (i = desc->cache_entry_index; i < array->size; i++) { 759 struct nfs_cache_array_entry *ent; 760 761 ent = &array->array[i]; 762 if (!dir_emit(desc->ctx, ent->string.name, ent->string.len, 763 nfs_compat_user_ino64(ent->ino), ent->d_type)) { 764 desc->eof = 1; 765 break; 766 } 767 desc->ctx->pos++; 768 if (i < (array->size-1)) 769 *desc->dir_cookie = array->array[i+1].cookie; 770 else 771 *desc->dir_cookie = array->last_cookie; 772 if (ctx->duped != 0) 773 ctx->duped = 1; 774 } 775 if (array->eof_index >= 0) 776 desc->eof = 1; 777 778 kunmap(desc->page); 779 cache_page_release(desc); 780 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", 781 (unsigned long long)*desc->dir_cookie, res); 782 return res; 783 } 784 785 /* 786 * If we cannot find a cookie in our cache, we suspect that this is 787 * because it points to a deleted file, so we ask the server to return 788 * whatever it thinks is the next entry. We then feed this to filldir. 789 * If all goes well, we should then be able to find our way round the 790 * cache on the next call to readdir_search_pagecache(); 791 * 792 * NOTE: we cannot add the anonymous page to the pagecache because 793 * the data it contains might not be page aligned. Besides, 794 * we should already have a complete representation of the 795 * directory in the page cache by the time we get here. 796 */ 797 static inline 798 int uncached_readdir(nfs_readdir_descriptor_t *desc) 799 { 800 struct page *page = NULL; 801 int status; 802 struct inode *inode = file_inode(desc->file); 803 struct nfs_open_dir_context *ctx = desc->file->private_data; 804 805 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n", 806 (unsigned long long)*desc->dir_cookie); 807 808 page = alloc_page(GFP_HIGHUSER); 809 if (!page) { 810 status = -ENOMEM; 811 goto out; 812 } 813 814 desc->page_index = 0; 815 desc->last_cookie = *desc->dir_cookie; 816 desc->page = page; 817 ctx->duped = 0; 818 819 status = nfs_readdir_xdr_to_array(desc, page, inode); 820 if (status < 0) 821 goto out_release; 822 823 status = nfs_do_filldir(desc); 824 825 out: 826 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", 827 __func__, status); 828 return status; 829 out_release: 830 cache_page_release(desc); 831 goto out; 832 } 833 834 /* The file offset position represents the dirent entry number. A 835 last cookie cache takes care of the common case of reading the 836 whole directory. 837 */ 838 static int nfs_readdir(struct file *file, struct dir_context *ctx) 839 { 840 struct dentry *dentry = file_dentry(file); 841 struct inode *inode = d_inode(dentry); 842 nfs_readdir_descriptor_t my_desc, 843 *desc = &my_desc; 844 struct nfs_open_dir_context *dir_ctx = file->private_data; 845 int res = 0; 846 847 dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n", 848 file, (long long)ctx->pos); 849 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); 850 851 /* 852 * ctx->pos points to the dirent entry number. 853 * *desc->dir_cookie has the cookie for the next entry. We have 854 * to either find the entry with the appropriate number or 855 * revalidate the cookie. 856 */ 857 memset(desc, 0, sizeof(*desc)); 858 859 desc->file = file; 860 desc->ctx = ctx; 861 desc->dir_cookie = &dir_ctx->dir_cookie; 862 desc->decode = NFS_PROTO(inode)->decode_dirent; 863 desc->plus = nfs_use_readdirplus(inode, ctx); 864 865 if (ctx->pos == 0 || nfs_attribute_cache_expired(inode)) 866 res = nfs_revalidate_mapping(inode, file->f_mapping); 867 if (res < 0) 868 goto out; 869 870 do { 871 res = readdir_search_pagecache(desc); 872 873 if (res == -EBADCOOKIE) { 874 res = 0; 875 /* This means either end of directory */ 876 if (*desc->dir_cookie && desc->eof == 0) { 877 /* Or that the server has 'lost' a cookie */ 878 res = uncached_readdir(desc); 879 if (res == 0) 880 continue; 881 } 882 break; 883 } 884 if (res == -ETOOSMALL && desc->plus) { 885 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 886 nfs_zap_caches(inode); 887 desc->page_index = 0; 888 desc->plus = false; 889 desc->eof = false; 890 continue; 891 } 892 if (res < 0) 893 break; 894 895 res = nfs_do_filldir(desc); 896 if (res < 0) 897 break; 898 } while (!desc->eof); 899 out: 900 if (res > 0) 901 res = 0; 902 dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res); 903 return res; 904 } 905 906 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) 907 { 908 struct inode *inode = file_inode(filp); 909 struct nfs_open_dir_context *dir_ctx = filp->private_data; 910 911 dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n", 912 filp, offset, whence); 913 914 inode_lock(inode); 915 switch (whence) { 916 case 1: 917 offset += filp->f_pos; 918 case 0: 919 if (offset >= 0) 920 break; 921 default: 922 offset = -EINVAL; 923 goto out; 924 } 925 if (offset != filp->f_pos) { 926 filp->f_pos = offset; 927 dir_ctx->dir_cookie = 0; 928 dir_ctx->duped = 0; 929 } 930 out: 931 inode_unlock(inode); 932 return offset; 933 } 934 935 /* 936 * All directory operations under NFS are synchronous, so fsync() 937 * is a dummy operation. 938 */ 939 static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end, 940 int datasync) 941 { 942 struct inode *inode = file_inode(filp); 943 944 dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync); 945 946 inode_lock(inode); 947 nfs_inc_stats(inode, NFSIOS_VFSFSYNC); 948 inode_unlock(inode); 949 return 0; 950 } 951 952 /** 953 * nfs_force_lookup_revalidate - Mark the directory as having changed 954 * @dir - pointer to directory inode 955 * 956 * This forces the revalidation code in nfs_lookup_revalidate() to do a 957 * full lookup on all child dentries of 'dir' whenever a change occurs 958 * on the server that might have invalidated our dcache. 959 * 960 * The caller should be holding dir->i_lock 961 */ 962 void nfs_force_lookup_revalidate(struct inode *dir) 963 { 964 NFS_I(dir)->cache_change_attribute++; 965 } 966 EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate); 967 968 /* 969 * A check for whether or not the parent directory has changed. 970 * In the case it has, we assume that the dentries are untrustworthy 971 * and may need to be looked up again. 972 * If rcu_walk prevents us from performing a full check, return 0. 973 */ 974 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry, 975 int rcu_walk) 976 { 977 if (IS_ROOT(dentry)) 978 return 1; 979 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE) 980 return 0; 981 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 982 return 0; 983 /* Revalidate nfsi->cache_change_attribute before we declare a match */ 984 if (nfs_mapping_need_revalidate_inode(dir)) { 985 if (rcu_walk) 986 return 0; 987 if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) 988 return 0; 989 } 990 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 991 return 0; 992 return 1; 993 } 994 995 /* 996 * Use intent information to check whether or not we're going to do 997 * an O_EXCL create using this path component. 998 */ 999 static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags) 1000 { 1001 if (NFS_PROTO(dir)->version == 2) 1002 return 0; 1003 return flags & LOOKUP_EXCL; 1004 } 1005 1006 /* 1007 * Inode and filehandle revalidation for lookups. 1008 * 1009 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, 1010 * or if the intent information indicates that we're about to open this 1011 * particular file and the "nocto" mount flag is not set. 1012 * 1013 */ 1014 static 1015 int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags) 1016 { 1017 struct nfs_server *server = NFS_SERVER(inode); 1018 int ret; 1019 1020 if (IS_AUTOMOUNT(inode)) 1021 return 0; 1022 /* VFS wants an on-the-wire revalidation */ 1023 if (flags & LOOKUP_REVAL) 1024 goto out_force; 1025 /* This is an open(2) */ 1026 if ((flags & LOOKUP_OPEN) && !(server->flags & NFS_MOUNT_NOCTO) && 1027 (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) 1028 goto out_force; 1029 out: 1030 return (inode->i_nlink == 0) ? -ENOENT : 0; 1031 out_force: 1032 if (flags & LOOKUP_RCU) 1033 return -ECHILD; 1034 ret = __nfs_revalidate_inode(server, inode); 1035 if (ret != 0) 1036 return ret; 1037 goto out; 1038 } 1039 1040 /* 1041 * We judge how long we want to trust negative 1042 * dentries by looking at the parent inode mtime. 1043 * 1044 * If parent mtime has changed, we revalidate, else we wait for a 1045 * period corresponding to the parent's attribute cache timeout value. 1046 * 1047 * If LOOKUP_RCU prevents us from performing a full check, return 1 1048 * suggesting a reval is needed. 1049 */ 1050 static inline 1051 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 1052 unsigned int flags) 1053 { 1054 /* Don't revalidate a negative dentry if we're creating a new file */ 1055 if (flags & LOOKUP_CREATE) 1056 return 0; 1057 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) 1058 return 1; 1059 return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU); 1060 } 1061 1062 /* 1063 * This is called every time the dcache has a lookup hit, 1064 * and we should check whether we can really trust that 1065 * lookup. 1066 * 1067 * NOTE! The hit can be a negative hit too, don't assume 1068 * we have an inode! 1069 * 1070 * If the parent directory is seen to have changed, we throw out the 1071 * cached dentry and do a new lookup. 1072 */ 1073 static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags) 1074 { 1075 struct inode *dir; 1076 struct inode *inode; 1077 struct dentry *parent; 1078 struct nfs_fh *fhandle = NULL; 1079 struct nfs_fattr *fattr = NULL; 1080 struct nfs4_label *label = NULL; 1081 int error; 1082 1083 if (flags & LOOKUP_RCU) { 1084 parent = ACCESS_ONCE(dentry->d_parent); 1085 dir = d_inode_rcu(parent); 1086 if (!dir) 1087 return -ECHILD; 1088 } else { 1089 parent = dget_parent(dentry); 1090 dir = d_inode(parent); 1091 } 1092 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); 1093 inode = d_inode(dentry); 1094 1095 if (!inode) { 1096 if (nfs_neg_need_reval(dir, dentry, flags)) { 1097 if (flags & LOOKUP_RCU) 1098 return -ECHILD; 1099 goto out_bad; 1100 } 1101 goto out_valid; 1102 } 1103 1104 if (is_bad_inode(inode)) { 1105 if (flags & LOOKUP_RCU) 1106 return -ECHILD; 1107 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", 1108 __func__, dentry); 1109 goto out_bad; 1110 } 1111 1112 if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ)) 1113 goto out_set_verifier; 1114 1115 /* Force a full look up iff the parent directory has changed */ 1116 if (!nfs_is_exclusive_create(dir, flags) && 1117 nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) { 1118 error = nfs_lookup_verify_inode(inode, flags); 1119 if (error) { 1120 if (flags & LOOKUP_RCU) 1121 return -ECHILD; 1122 if (error == -ESTALE) 1123 goto out_zap_parent; 1124 goto out_error; 1125 } 1126 nfs_advise_use_readdirplus(dir); 1127 goto out_valid; 1128 } 1129 1130 if (flags & LOOKUP_RCU) 1131 return -ECHILD; 1132 1133 if (NFS_STALE(inode)) 1134 goto out_bad; 1135 1136 error = -ENOMEM; 1137 fhandle = nfs_alloc_fhandle(); 1138 fattr = nfs_alloc_fattr(); 1139 if (fhandle == NULL || fattr == NULL) 1140 goto out_error; 1141 1142 label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT); 1143 if (IS_ERR(label)) 1144 goto out_error; 1145 1146 trace_nfs_lookup_revalidate_enter(dir, dentry, flags); 1147 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label); 1148 trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error); 1149 if (error == -ESTALE || error == -ENOENT) 1150 goto out_bad; 1151 if (error) 1152 goto out_error; 1153 if (nfs_compare_fh(NFS_FH(inode), fhandle)) 1154 goto out_bad; 1155 if ((error = nfs_refresh_inode(inode, fattr)) != 0) 1156 goto out_bad; 1157 1158 nfs_setsecurity(inode, fattr, label); 1159 1160 nfs_free_fattr(fattr); 1161 nfs_free_fhandle(fhandle); 1162 nfs4_label_free(label); 1163 1164 /* set a readdirplus hint that we had a cache miss */ 1165 nfs_force_use_readdirplus(dir); 1166 1167 out_set_verifier: 1168 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1169 out_valid: 1170 if (flags & LOOKUP_RCU) { 1171 if (parent != ACCESS_ONCE(dentry->d_parent)) 1172 return -ECHILD; 1173 } else 1174 dput(parent); 1175 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n", 1176 __func__, dentry); 1177 return 1; 1178 out_zap_parent: 1179 nfs_zap_caches(dir); 1180 out_bad: 1181 WARN_ON(flags & LOOKUP_RCU); 1182 nfs_free_fattr(fattr); 1183 nfs_free_fhandle(fhandle); 1184 nfs4_label_free(label); 1185 nfs_mark_for_revalidate(dir); 1186 if (inode && S_ISDIR(inode->i_mode)) { 1187 /* Purge readdir caches. */ 1188 nfs_zap_caches(inode); 1189 /* 1190 * We can't d_drop the root of a disconnected tree: 1191 * its d_hash is on the s_anon list and d_drop() would hide 1192 * it from shrink_dcache_for_unmount(), leading to busy 1193 * inodes on unmount and further oopses. 1194 */ 1195 if (IS_ROOT(dentry)) 1196 goto out_valid; 1197 } 1198 dput(parent); 1199 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n", 1200 __func__, dentry); 1201 return 0; 1202 out_error: 1203 WARN_ON(flags & LOOKUP_RCU); 1204 nfs_free_fattr(fattr); 1205 nfs_free_fhandle(fhandle); 1206 nfs4_label_free(label); 1207 dput(parent); 1208 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n", 1209 __func__, dentry, error); 1210 return error; 1211 } 1212 1213 /* 1214 * A weaker form of d_revalidate for revalidating just the d_inode(dentry) 1215 * when we don't really care about the dentry name. This is called when a 1216 * pathwalk ends on a dentry that was not found via a normal lookup in the 1217 * parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals). 1218 * 1219 * In this situation, we just want to verify that the inode itself is OK 1220 * since the dentry might have changed on the server. 1221 */ 1222 static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags) 1223 { 1224 struct inode *inode = d_inode(dentry); 1225 int error = 0; 1226 1227 /* 1228 * I believe we can only get a negative dentry here in the case of a 1229 * procfs-style symlink. Just assume it's correct for now, but we may 1230 * eventually need to do something more here. 1231 */ 1232 if (!inode) { 1233 dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n", 1234 __func__, dentry); 1235 return 1; 1236 } 1237 1238 if (is_bad_inode(inode)) { 1239 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", 1240 __func__, dentry); 1241 return 0; 1242 } 1243 1244 if (nfs_mapping_need_revalidate_inode(inode)) 1245 error = __nfs_revalidate_inode(NFS_SERVER(inode), inode); 1246 dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n", 1247 __func__, inode->i_ino, error ? "invalid" : "valid"); 1248 return !error; 1249 } 1250 1251 /* 1252 * This is called from dput() when d_count is going to 0. 1253 */ 1254 static int nfs_dentry_delete(const struct dentry *dentry) 1255 { 1256 dfprintk(VFS, "NFS: dentry_delete(%pd2, %x)\n", 1257 dentry, dentry->d_flags); 1258 1259 /* Unhash any dentry with a stale inode */ 1260 if (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry))) 1261 return 1; 1262 1263 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1264 /* Unhash it, so that ->d_iput() would be called */ 1265 return 1; 1266 } 1267 if (!(dentry->d_sb->s_flags & MS_ACTIVE)) { 1268 /* Unhash it, so that ancestors of killed async unlink 1269 * files will be cleaned up during umount */ 1270 return 1; 1271 } 1272 return 0; 1273 1274 } 1275 1276 /* Ensure that we revalidate inode->i_nlink */ 1277 static void nfs_drop_nlink(struct inode *inode) 1278 { 1279 spin_lock(&inode->i_lock); 1280 /* drop the inode if we're reasonably sure this is the last link */ 1281 if (inode->i_nlink == 1) 1282 clear_nlink(inode); 1283 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATTR; 1284 spin_unlock(&inode->i_lock); 1285 } 1286 1287 /* 1288 * Called when the dentry loses inode. 1289 * We use it to clean up silly-renamed files. 1290 */ 1291 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) 1292 { 1293 if (S_ISDIR(inode->i_mode)) 1294 /* drop any readdir cache as it could easily be old */ 1295 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA; 1296 1297 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1298 nfs_complete_unlink(dentry, inode); 1299 nfs_drop_nlink(inode); 1300 } 1301 iput(inode); 1302 } 1303 1304 static void nfs_d_release(struct dentry *dentry) 1305 { 1306 /* free cached devname value, if it survived that far */ 1307 if (unlikely(dentry->d_fsdata)) { 1308 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 1309 WARN_ON(1); 1310 else 1311 kfree(dentry->d_fsdata); 1312 } 1313 } 1314 1315 const struct dentry_operations nfs_dentry_operations = { 1316 .d_revalidate = nfs_lookup_revalidate, 1317 .d_weak_revalidate = nfs_weak_revalidate, 1318 .d_delete = nfs_dentry_delete, 1319 .d_iput = nfs_dentry_iput, 1320 .d_automount = nfs_d_automount, 1321 .d_release = nfs_d_release, 1322 }; 1323 EXPORT_SYMBOL_GPL(nfs_dentry_operations); 1324 1325 struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) 1326 { 1327 struct dentry *res; 1328 struct inode *inode = NULL; 1329 struct nfs_fh *fhandle = NULL; 1330 struct nfs_fattr *fattr = NULL; 1331 struct nfs4_label *label = NULL; 1332 int error; 1333 1334 dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry); 1335 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); 1336 1337 if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen)) 1338 return ERR_PTR(-ENAMETOOLONG); 1339 1340 /* 1341 * If we're doing an exclusive create, optimize away the lookup 1342 * but don't hash the dentry. 1343 */ 1344 if (nfs_is_exclusive_create(dir, flags)) 1345 return NULL; 1346 1347 res = ERR_PTR(-ENOMEM); 1348 fhandle = nfs_alloc_fhandle(); 1349 fattr = nfs_alloc_fattr(); 1350 if (fhandle == NULL || fattr == NULL) 1351 goto out; 1352 1353 label = nfs4_label_alloc(NFS_SERVER(dir), GFP_NOWAIT); 1354 if (IS_ERR(label)) 1355 goto out; 1356 1357 trace_nfs_lookup_enter(dir, dentry, flags); 1358 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label); 1359 if (error == -ENOENT) 1360 goto no_entry; 1361 if (error < 0) { 1362 res = ERR_PTR(error); 1363 goto out_label; 1364 } 1365 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); 1366 res = ERR_CAST(inode); 1367 if (IS_ERR(res)) 1368 goto out_label; 1369 1370 /* Notify readdir to use READDIRPLUS */ 1371 nfs_force_use_readdirplus(dir); 1372 1373 no_entry: 1374 res = d_splice_alias(inode, dentry); 1375 if (res != NULL) { 1376 if (IS_ERR(res)) 1377 goto out_label; 1378 dentry = res; 1379 } 1380 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1381 out_label: 1382 trace_nfs_lookup_exit(dir, dentry, flags, error); 1383 nfs4_label_free(label); 1384 out: 1385 nfs_free_fattr(fattr); 1386 nfs_free_fhandle(fhandle); 1387 return res; 1388 } 1389 EXPORT_SYMBOL_GPL(nfs_lookup); 1390 1391 #if IS_ENABLED(CONFIG_NFS_V4) 1392 static int nfs4_lookup_revalidate(struct dentry *, unsigned int); 1393 1394 const struct dentry_operations nfs4_dentry_operations = { 1395 .d_revalidate = nfs4_lookup_revalidate, 1396 .d_delete = nfs_dentry_delete, 1397 .d_iput = nfs_dentry_iput, 1398 .d_automount = nfs_d_automount, 1399 .d_release = nfs_d_release, 1400 }; 1401 EXPORT_SYMBOL_GPL(nfs4_dentry_operations); 1402 1403 static fmode_t flags_to_mode(int flags) 1404 { 1405 fmode_t res = (__force fmode_t)flags & FMODE_EXEC; 1406 if ((flags & O_ACCMODE) != O_WRONLY) 1407 res |= FMODE_READ; 1408 if ((flags & O_ACCMODE) != O_RDONLY) 1409 res |= FMODE_WRITE; 1410 return res; 1411 } 1412 1413 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp) 1414 { 1415 return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp); 1416 } 1417 1418 static int do_open(struct inode *inode, struct file *filp) 1419 { 1420 nfs_fscache_open_file(inode, filp); 1421 return 0; 1422 } 1423 1424 static int nfs_finish_open(struct nfs_open_context *ctx, 1425 struct dentry *dentry, 1426 struct file *file, unsigned open_flags, 1427 int *opened) 1428 { 1429 int err; 1430 1431 err = finish_open(file, dentry, do_open, opened); 1432 if (err) 1433 goto out; 1434 if (S_ISREG(file->f_path.dentry->d_inode->i_mode)) 1435 nfs_file_set_open_context(file, ctx); 1436 else 1437 err = -ESTALE; 1438 out: 1439 return err; 1440 } 1441 1442 int nfs_atomic_open(struct inode *dir, struct dentry *dentry, 1443 struct file *file, unsigned open_flags, 1444 umode_t mode, int *opened) 1445 { 1446 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 1447 struct nfs_open_context *ctx; 1448 struct dentry *res; 1449 struct iattr attr = { .ia_valid = ATTR_OPEN }; 1450 struct inode *inode; 1451 unsigned int lookup_flags = 0; 1452 bool switched = false; 1453 int err; 1454 1455 /* Expect a negative dentry */ 1456 BUG_ON(d_inode(dentry)); 1457 1458 dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n", 1459 dir->i_sb->s_id, dir->i_ino, dentry); 1460 1461 err = nfs_check_flags(open_flags); 1462 if (err) 1463 return err; 1464 1465 /* NFS only supports OPEN on regular files */ 1466 if ((open_flags & O_DIRECTORY)) { 1467 if (!d_in_lookup(dentry)) { 1468 /* 1469 * Hashed negative dentry with O_DIRECTORY: dentry was 1470 * revalidated and is fine, no need to perform lookup 1471 * again 1472 */ 1473 return -ENOENT; 1474 } 1475 lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY; 1476 goto no_open; 1477 } 1478 1479 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 1480 return -ENAMETOOLONG; 1481 1482 if (open_flags & O_CREAT) { 1483 struct nfs_server *server = NFS_SERVER(dir); 1484 1485 if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK)) 1486 mode &= ~current_umask(); 1487 1488 attr.ia_valid |= ATTR_MODE; 1489 attr.ia_mode = mode; 1490 } 1491 if (open_flags & O_TRUNC) { 1492 attr.ia_valid |= ATTR_SIZE; 1493 attr.ia_size = 0; 1494 } 1495 1496 if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) { 1497 d_drop(dentry); 1498 switched = true; 1499 dentry = d_alloc_parallel(dentry->d_parent, 1500 &dentry->d_name, &wq); 1501 if (IS_ERR(dentry)) 1502 return PTR_ERR(dentry); 1503 if (unlikely(!d_in_lookup(dentry))) 1504 return finish_no_open(file, dentry); 1505 } 1506 1507 ctx = create_nfs_open_context(dentry, open_flags, file); 1508 err = PTR_ERR(ctx); 1509 if (IS_ERR(ctx)) 1510 goto out; 1511 1512 trace_nfs_atomic_open_enter(dir, ctx, open_flags); 1513 inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, opened); 1514 if (IS_ERR(inode)) { 1515 err = PTR_ERR(inode); 1516 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); 1517 put_nfs_open_context(ctx); 1518 d_drop(dentry); 1519 switch (err) { 1520 case -ENOENT: 1521 d_splice_alias(NULL, dentry); 1522 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1523 break; 1524 case -EISDIR: 1525 case -ENOTDIR: 1526 goto no_open; 1527 case -ELOOP: 1528 if (!(open_flags & O_NOFOLLOW)) 1529 goto no_open; 1530 break; 1531 /* case -EINVAL: */ 1532 default: 1533 break; 1534 } 1535 goto out; 1536 } 1537 1538 err = nfs_finish_open(ctx, ctx->dentry, file, open_flags, opened); 1539 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); 1540 put_nfs_open_context(ctx); 1541 out: 1542 if (unlikely(switched)) { 1543 d_lookup_done(dentry); 1544 dput(dentry); 1545 } 1546 return err; 1547 1548 no_open: 1549 res = nfs_lookup(dir, dentry, lookup_flags); 1550 if (switched) { 1551 d_lookup_done(dentry); 1552 if (!res) 1553 res = dentry; 1554 else 1555 dput(dentry); 1556 } 1557 if (IS_ERR(res)) 1558 return PTR_ERR(res); 1559 return finish_no_open(file, res); 1560 } 1561 EXPORT_SYMBOL_GPL(nfs_atomic_open); 1562 1563 static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) 1564 { 1565 struct inode *inode; 1566 int ret = 0; 1567 1568 if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY)) 1569 goto no_open; 1570 if (d_mountpoint(dentry)) 1571 goto no_open; 1572 if (NFS_SB(dentry->d_sb)->caps & NFS_CAP_ATOMIC_OPEN_V1) 1573 goto no_open; 1574 1575 inode = d_inode(dentry); 1576 1577 /* We can't create new files in nfs_open_revalidate(), so we 1578 * optimize away revalidation of negative dentries. 1579 */ 1580 if (inode == NULL) { 1581 struct dentry *parent; 1582 struct inode *dir; 1583 1584 if (flags & LOOKUP_RCU) { 1585 parent = ACCESS_ONCE(dentry->d_parent); 1586 dir = d_inode_rcu(parent); 1587 if (!dir) 1588 return -ECHILD; 1589 } else { 1590 parent = dget_parent(dentry); 1591 dir = d_inode(parent); 1592 } 1593 if (!nfs_neg_need_reval(dir, dentry, flags)) 1594 ret = 1; 1595 else if (flags & LOOKUP_RCU) 1596 ret = -ECHILD; 1597 if (!(flags & LOOKUP_RCU)) 1598 dput(parent); 1599 else if (parent != ACCESS_ONCE(dentry->d_parent)) 1600 return -ECHILD; 1601 goto out; 1602 } 1603 1604 /* NFS only supports OPEN on regular files */ 1605 if (!S_ISREG(inode->i_mode)) 1606 goto no_open; 1607 /* We cannot do exclusive creation on a positive dentry */ 1608 if (flags & LOOKUP_EXCL) 1609 goto no_open; 1610 1611 /* Let f_op->open() actually open (and revalidate) the file */ 1612 ret = 1; 1613 1614 out: 1615 return ret; 1616 1617 no_open: 1618 return nfs_lookup_revalidate(dentry, flags); 1619 } 1620 1621 #endif /* CONFIG_NFSV4 */ 1622 1623 /* 1624 * Code common to create, mkdir, and mknod. 1625 */ 1626 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, 1627 struct nfs_fattr *fattr, 1628 struct nfs4_label *label) 1629 { 1630 struct dentry *parent = dget_parent(dentry); 1631 struct inode *dir = d_inode(parent); 1632 struct inode *inode; 1633 int error = -EACCES; 1634 1635 d_drop(dentry); 1636 1637 /* We may have been initialized further down */ 1638 if (d_really_is_positive(dentry)) 1639 goto out; 1640 if (fhandle->size == 0) { 1641 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, NULL); 1642 if (error) 1643 goto out_error; 1644 } 1645 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1646 if (!(fattr->valid & NFS_ATTR_FATTR)) { 1647 struct nfs_server *server = NFS_SB(dentry->d_sb); 1648 error = server->nfs_client->rpc_ops->getattr(server, fhandle, fattr, NULL); 1649 if (error < 0) 1650 goto out_error; 1651 } 1652 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); 1653 error = PTR_ERR(inode); 1654 if (IS_ERR(inode)) 1655 goto out_error; 1656 d_add(dentry, inode); 1657 out: 1658 dput(parent); 1659 return 0; 1660 out_error: 1661 nfs_mark_for_revalidate(dir); 1662 dput(parent); 1663 return error; 1664 } 1665 EXPORT_SYMBOL_GPL(nfs_instantiate); 1666 1667 /* 1668 * Following a failed create operation, we drop the dentry rather 1669 * than retain a negative dentry. This avoids a problem in the event 1670 * that the operation succeeded on the server, but an error in the 1671 * reply path made it appear to have failed. 1672 */ 1673 int nfs_create(struct inode *dir, struct dentry *dentry, 1674 umode_t mode, bool excl) 1675 { 1676 struct iattr attr; 1677 int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT; 1678 int error; 1679 1680 dfprintk(VFS, "NFS: create(%s/%lu), %pd\n", 1681 dir->i_sb->s_id, dir->i_ino, dentry); 1682 1683 attr.ia_mode = mode; 1684 attr.ia_valid = ATTR_MODE; 1685 1686 trace_nfs_create_enter(dir, dentry, open_flags); 1687 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags); 1688 trace_nfs_create_exit(dir, dentry, open_flags, error); 1689 if (error != 0) 1690 goto out_err; 1691 return 0; 1692 out_err: 1693 d_drop(dentry); 1694 return error; 1695 } 1696 EXPORT_SYMBOL_GPL(nfs_create); 1697 1698 /* 1699 * See comments for nfs_proc_create regarding failed operations. 1700 */ 1701 int 1702 nfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev) 1703 { 1704 struct iattr attr; 1705 int status; 1706 1707 dfprintk(VFS, "NFS: mknod(%s/%lu), %pd\n", 1708 dir->i_sb->s_id, dir->i_ino, dentry); 1709 1710 attr.ia_mode = mode; 1711 attr.ia_valid = ATTR_MODE; 1712 1713 trace_nfs_mknod_enter(dir, dentry); 1714 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); 1715 trace_nfs_mknod_exit(dir, dentry, status); 1716 if (status != 0) 1717 goto out_err; 1718 return 0; 1719 out_err: 1720 d_drop(dentry); 1721 return status; 1722 } 1723 EXPORT_SYMBOL_GPL(nfs_mknod); 1724 1725 /* 1726 * See comments for nfs_proc_create regarding failed operations. 1727 */ 1728 int nfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 1729 { 1730 struct iattr attr; 1731 int error; 1732 1733 dfprintk(VFS, "NFS: mkdir(%s/%lu), %pd\n", 1734 dir->i_sb->s_id, dir->i_ino, dentry); 1735 1736 attr.ia_valid = ATTR_MODE; 1737 attr.ia_mode = mode | S_IFDIR; 1738 1739 trace_nfs_mkdir_enter(dir, dentry); 1740 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); 1741 trace_nfs_mkdir_exit(dir, dentry, error); 1742 if (error != 0) 1743 goto out_err; 1744 return 0; 1745 out_err: 1746 d_drop(dentry); 1747 return error; 1748 } 1749 EXPORT_SYMBOL_GPL(nfs_mkdir); 1750 1751 static void nfs_dentry_handle_enoent(struct dentry *dentry) 1752 { 1753 if (simple_positive(dentry)) 1754 d_delete(dentry); 1755 } 1756 1757 int nfs_rmdir(struct inode *dir, struct dentry *dentry) 1758 { 1759 int error; 1760 1761 dfprintk(VFS, "NFS: rmdir(%s/%lu), %pd\n", 1762 dir->i_sb->s_id, dir->i_ino, dentry); 1763 1764 trace_nfs_rmdir_enter(dir, dentry); 1765 if (d_really_is_positive(dentry)) { 1766 down_write(&NFS_I(d_inode(dentry))->rmdir_sem); 1767 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 1768 /* Ensure the VFS deletes this inode */ 1769 switch (error) { 1770 case 0: 1771 clear_nlink(d_inode(dentry)); 1772 break; 1773 case -ENOENT: 1774 nfs_dentry_handle_enoent(dentry); 1775 } 1776 up_write(&NFS_I(d_inode(dentry))->rmdir_sem); 1777 } else 1778 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 1779 trace_nfs_rmdir_exit(dir, dentry, error); 1780 1781 return error; 1782 } 1783 EXPORT_SYMBOL_GPL(nfs_rmdir); 1784 1785 /* 1786 * Remove a file after making sure there are no pending writes, 1787 * and after checking that the file has only one user. 1788 * 1789 * We invalidate the attribute cache and free the inode prior to the operation 1790 * to avoid possible races if the server reuses the inode. 1791 */ 1792 static int nfs_safe_remove(struct dentry *dentry) 1793 { 1794 struct inode *dir = d_inode(dentry->d_parent); 1795 struct inode *inode = d_inode(dentry); 1796 int error = -EBUSY; 1797 1798 dfprintk(VFS, "NFS: safe_remove(%pd2)\n", dentry); 1799 1800 /* If the dentry was sillyrenamed, we simply call d_delete() */ 1801 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1802 error = 0; 1803 goto out; 1804 } 1805 1806 trace_nfs_remove_enter(dir, dentry); 1807 if (inode != NULL) { 1808 NFS_PROTO(inode)->return_delegation(inode); 1809 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1810 if (error == 0) 1811 nfs_drop_nlink(inode); 1812 } else 1813 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1814 if (error == -ENOENT) 1815 nfs_dentry_handle_enoent(dentry); 1816 trace_nfs_remove_exit(dir, dentry, error); 1817 out: 1818 return error; 1819 } 1820 1821 /* We do silly rename. In case sillyrename() returns -EBUSY, the inode 1822 * belongs to an active ".nfs..." file and we return -EBUSY. 1823 * 1824 * If sillyrename() returns 0, we do nothing, otherwise we unlink. 1825 */ 1826 int nfs_unlink(struct inode *dir, struct dentry *dentry) 1827 { 1828 int error; 1829 int need_rehash = 0; 1830 1831 dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id, 1832 dir->i_ino, dentry); 1833 1834 trace_nfs_unlink_enter(dir, dentry); 1835 spin_lock(&dentry->d_lock); 1836 if (d_count(dentry) > 1) { 1837 spin_unlock(&dentry->d_lock); 1838 /* Start asynchronous writeout of the inode */ 1839 write_inode_now(d_inode(dentry), 0); 1840 error = nfs_sillyrename(dir, dentry); 1841 goto out; 1842 } 1843 if (!d_unhashed(dentry)) { 1844 __d_drop(dentry); 1845 need_rehash = 1; 1846 } 1847 spin_unlock(&dentry->d_lock); 1848 error = nfs_safe_remove(dentry); 1849 if (!error || error == -ENOENT) { 1850 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1851 } else if (need_rehash) 1852 d_rehash(dentry); 1853 out: 1854 trace_nfs_unlink_exit(dir, dentry, error); 1855 return error; 1856 } 1857 EXPORT_SYMBOL_GPL(nfs_unlink); 1858 1859 /* 1860 * To create a symbolic link, most file systems instantiate a new inode, 1861 * add a page to it containing the path, then write it out to the disk 1862 * using prepare_write/commit_write. 1863 * 1864 * Unfortunately the NFS client can't create the in-core inode first 1865 * because it needs a file handle to create an in-core inode (see 1866 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the 1867 * symlink request has completed on the server. 1868 * 1869 * So instead we allocate a raw page, copy the symname into it, then do 1870 * the SYMLINK request with the page as the buffer. If it succeeds, we 1871 * now have a new file handle and can instantiate an in-core NFS inode 1872 * and move the raw page into its mapping. 1873 */ 1874 int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) 1875 { 1876 struct page *page; 1877 char *kaddr; 1878 struct iattr attr; 1879 unsigned int pathlen = strlen(symname); 1880 int error; 1881 1882 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id, 1883 dir->i_ino, dentry, symname); 1884 1885 if (pathlen > PAGE_SIZE) 1886 return -ENAMETOOLONG; 1887 1888 attr.ia_mode = S_IFLNK | S_IRWXUGO; 1889 attr.ia_valid = ATTR_MODE; 1890 1891 page = alloc_page(GFP_USER); 1892 if (!page) 1893 return -ENOMEM; 1894 1895 kaddr = page_address(page); 1896 memcpy(kaddr, symname, pathlen); 1897 if (pathlen < PAGE_SIZE) 1898 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); 1899 1900 trace_nfs_symlink_enter(dir, dentry); 1901 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr); 1902 trace_nfs_symlink_exit(dir, dentry, error); 1903 if (error != 0) { 1904 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n", 1905 dir->i_sb->s_id, dir->i_ino, 1906 dentry, symname, error); 1907 d_drop(dentry); 1908 __free_page(page); 1909 return error; 1910 } 1911 1912 /* 1913 * No big deal if we can't add this page to the page cache here. 1914 * READLINK will get the missing page from the server if needed. 1915 */ 1916 if (!add_to_page_cache_lru(page, d_inode(dentry)->i_mapping, 0, 1917 GFP_KERNEL)) { 1918 SetPageUptodate(page); 1919 unlock_page(page); 1920 /* 1921 * add_to_page_cache_lru() grabs an extra page refcount. 1922 * Drop it here to avoid leaking this page later. 1923 */ 1924 put_page(page); 1925 } else 1926 __free_page(page); 1927 1928 return 0; 1929 } 1930 EXPORT_SYMBOL_GPL(nfs_symlink); 1931 1932 int 1933 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 1934 { 1935 struct inode *inode = d_inode(old_dentry); 1936 int error; 1937 1938 dfprintk(VFS, "NFS: link(%pd2 -> %pd2)\n", 1939 old_dentry, dentry); 1940 1941 trace_nfs_link_enter(inode, dir, dentry); 1942 NFS_PROTO(inode)->return_delegation(inode); 1943 1944 d_drop(dentry); 1945 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 1946 if (error == 0) { 1947 ihold(inode); 1948 d_add(dentry, inode); 1949 } 1950 trace_nfs_link_exit(inode, dir, dentry, error); 1951 return error; 1952 } 1953 EXPORT_SYMBOL_GPL(nfs_link); 1954 1955 /* 1956 * RENAME 1957 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a 1958 * different file handle for the same inode after a rename (e.g. when 1959 * moving to a different directory). A fail-safe method to do so would 1960 * be to look up old_dir/old_name, create a link to new_dir/new_name and 1961 * rename the old file using the sillyrename stuff. This way, the original 1962 * file in old_dir will go away when the last process iput()s the inode. 1963 * 1964 * FIXED. 1965 * 1966 * It actually works quite well. One needs to have the possibility for 1967 * at least one ".nfs..." file in each directory the file ever gets 1968 * moved or linked to which happens automagically with the new 1969 * implementation that only depends on the dcache stuff instead of 1970 * using the inode layer 1971 * 1972 * Unfortunately, things are a little more complicated than indicated 1973 * above. For a cross-directory move, we want to make sure we can get 1974 * rid of the old inode after the operation. This means there must be 1975 * no pending writes (if it's a file), and the use count must be 1. 1976 * If these conditions are met, we can drop the dentries before doing 1977 * the rename. 1978 */ 1979 int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, 1980 struct inode *new_dir, struct dentry *new_dentry, 1981 unsigned int flags) 1982 { 1983 struct inode *old_inode = d_inode(old_dentry); 1984 struct inode *new_inode = d_inode(new_dentry); 1985 struct dentry *dentry = NULL, *rehash = NULL; 1986 struct rpc_task *task; 1987 int error = -EBUSY; 1988 1989 if (flags) 1990 return -EINVAL; 1991 1992 dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n", 1993 old_dentry, new_dentry, 1994 d_count(new_dentry)); 1995 1996 trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry); 1997 /* 1998 * For non-directories, check whether the target is busy and if so, 1999 * make a copy of the dentry and then do a silly-rename. If the 2000 * silly-rename succeeds, the copied dentry is hashed and becomes 2001 * the new target. 2002 */ 2003 if (new_inode && !S_ISDIR(new_inode->i_mode)) { 2004 /* 2005 * To prevent any new references to the target during the 2006 * rename, we unhash the dentry in advance. 2007 */ 2008 if (!d_unhashed(new_dentry)) { 2009 d_drop(new_dentry); 2010 rehash = new_dentry; 2011 } 2012 2013 if (d_count(new_dentry) > 2) { 2014 int err; 2015 2016 /* copy the target dentry's name */ 2017 dentry = d_alloc(new_dentry->d_parent, 2018 &new_dentry->d_name); 2019 if (!dentry) 2020 goto out; 2021 2022 /* silly-rename the existing target ... */ 2023 err = nfs_sillyrename(new_dir, new_dentry); 2024 if (err) 2025 goto out; 2026 2027 new_dentry = dentry; 2028 rehash = NULL; 2029 new_inode = NULL; 2030 } 2031 } 2032 2033 NFS_PROTO(old_inode)->return_delegation(old_inode); 2034 if (new_inode != NULL) 2035 NFS_PROTO(new_inode)->return_delegation(new_inode); 2036 2037 task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL); 2038 if (IS_ERR(task)) { 2039 error = PTR_ERR(task); 2040 goto out; 2041 } 2042 2043 error = rpc_wait_for_completion_task(task); 2044 if (error != 0) { 2045 ((struct nfs_renamedata *)task->tk_calldata)->cancelled = 1; 2046 /* Paired with the atomic_dec_and_test() barrier in rpc_do_put_task() */ 2047 smp_wmb(); 2048 } else 2049 error = task->tk_status; 2050 rpc_put_task(task); 2051 nfs_mark_for_revalidate(old_inode); 2052 out: 2053 if (rehash) 2054 d_rehash(rehash); 2055 trace_nfs_rename_exit(old_dir, old_dentry, 2056 new_dir, new_dentry, error); 2057 if (!error) { 2058 if (new_inode != NULL) 2059 nfs_drop_nlink(new_inode); 2060 /* 2061 * The d_move() should be here instead of in an async RPC completion 2062 * handler because we need the proper locks to move the dentry. If 2063 * we're interrupted by a signal, the async RPC completion handler 2064 * should mark the directories for revalidation. 2065 */ 2066 d_move(old_dentry, new_dentry); 2067 nfs_set_verifier(new_dentry, 2068 nfs_save_change_attribute(new_dir)); 2069 } else if (error == -ENOENT) 2070 nfs_dentry_handle_enoent(old_dentry); 2071 2072 /* new dentry created? */ 2073 if (dentry) 2074 dput(dentry); 2075 return error; 2076 } 2077 EXPORT_SYMBOL_GPL(nfs_rename); 2078 2079 static DEFINE_SPINLOCK(nfs_access_lru_lock); 2080 static LIST_HEAD(nfs_access_lru_list); 2081 static atomic_long_t nfs_access_nr_entries; 2082 2083 static unsigned long nfs_access_max_cachesize = ULONG_MAX; 2084 module_param(nfs_access_max_cachesize, ulong, 0644); 2085 MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length"); 2086 2087 static void nfs_access_free_entry(struct nfs_access_entry *entry) 2088 { 2089 put_rpccred(entry->cred); 2090 kfree_rcu(entry, rcu_head); 2091 smp_mb__before_atomic(); 2092 atomic_long_dec(&nfs_access_nr_entries); 2093 smp_mb__after_atomic(); 2094 } 2095 2096 static void nfs_access_free_list(struct list_head *head) 2097 { 2098 struct nfs_access_entry *cache; 2099 2100 while (!list_empty(head)) { 2101 cache = list_entry(head->next, struct nfs_access_entry, lru); 2102 list_del(&cache->lru); 2103 nfs_access_free_entry(cache); 2104 } 2105 } 2106 2107 static unsigned long 2108 nfs_do_access_cache_scan(unsigned int nr_to_scan) 2109 { 2110 LIST_HEAD(head); 2111 struct nfs_inode *nfsi, *next; 2112 struct nfs_access_entry *cache; 2113 long freed = 0; 2114 2115 spin_lock(&nfs_access_lru_lock); 2116 list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) { 2117 struct inode *inode; 2118 2119 if (nr_to_scan-- == 0) 2120 break; 2121 inode = &nfsi->vfs_inode; 2122 spin_lock(&inode->i_lock); 2123 if (list_empty(&nfsi->access_cache_entry_lru)) 2124 goto remove_lru_entry; 2125 cache = list_entry(nfsi->access_cache_entry_lru.next, 2126 struct nfs_access_entry, lru); 2127 list_move(&cache->lru, &head); 2128 rb_erase(&cache->rb_node, &nfsi->access_cache); 2129 freed++; 2130 if (!list_empty(&nfsi->access_cache_entry_lru)) 2131 list_move_tail(&nfsi->access_cache_inode_lru, 2132 &nfs_access_lru_list); 2133 else { 2134 remove_lru_entry: 2135 list_del_init(&nfsi->access_cache_inode_lru); 2136 smp_mb__before_atomic(); 2137 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); 2138 smp_mb__after_atomic(); 2139 } 2140 spin_unlock(&inode->i_lock); 2141 } 2142 spin_unlock(&nfs_access_lru_lock); 2143 nfs_access_free_list(&head); 2144 return freed; 2145 } 2146 2147 unsigned long 2148 nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc) 2149 { 2150 int nr_to_scan = sc->nr_to_scan; 2151 gfp_t gfp_mask = sc->gfp_mask; 2152 2153 if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL) 2154 return SHRINK_STOP; 2155 return nfs_do_access_cache_scan(nr_to_scan); 2156 } 2157 2158 2159 unsigned long 2160 nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc) 2161 { 2162 return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries)); 2163 } 2164 2165 static void 2166 nfs_access_cache_enforce_limit(void) 2167 { 2168 long nr_entries = atomic_long_read(&nfs_access_nr_entries); 2169 unsigned long diff; 2170 unsigned int nr_to_scan; 2171 2172 if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize) 2173 return; 2174 nr_to_scan = 100; 2175 diff = nr_entries - nfs_access_max_cachesize; 2176 if (diff < nr_to_scan) 2177 nr_to_scan = diff; 2178 nfs_do_access_cache_scan(nr_to_scan); 2179 } 2180 2181 static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head) 2182 { 2183 struct rb_root *root_node = &nfsi->access_cache; 2184 struct rb_node *n; 2185 struct nfs_access_entry *entry; 2186 2187 /* Unhook entries from the cache */ 2188 while ((n = rb_first(root_node)) != NULL) { 2189 entry = rb_entry(n, struct nfs_access_entry, rb_node); 2190 rb_erase(n, root_node); 2191 list_move(&entry->lru, head); 2192 } 2193 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; 2194 } 2195 2196 void nfs_access_zap_cache(struct inode *inode) 2197 { 2198 LIST_HEAD(head); 2199 2200 if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0) 2201 return; 2202 /* Remove from global LRU init */ 2203 spin_lock(&nfs_access_lru_lock); 2204 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2205 list_del_init(&NFS_I(inode)->access_cache_inode_lru); 2206 2207 spin_lock(&inode->i_lock); 2208 __nfs_access_zap_cache(NFS_I(inode), &head); 2209 spin_unlock(&inode->i_lock); 2210 spin_unlock(&nfs_access_lru_lock); 2211 nfs_access_free_list(&head); 2212 } 2213 EXPORT_SYMBOL_GPL(nfs_access_zap_cache); 2214 2215 static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred) 2216 { 2217 struct rb_node *n = NFS_I(inode)->access_cache.rb_node; 2218 struct nfs_access_entry *entry; 2219 2220 while (n != NULL) { 2221 entry = rb_entry(n, struct nfs_access_entry, rb_node); 2222 2223 if (cred < entry->cred) 2224 n = n->rb_left; 2225 else if (cred > entry->cred) 2226 n = n->rb_right; 2227 else 2228 return entry; 2229 } 2230 return NULL; 2231 } 2232 2233 static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res, bool may_block) 2234 { 2235 struct nfs_inode *nfsi = NFS_I(inode); 2236 struct nfs_access_entry *cache; 2237 bool retry = true; 2238 int err; 2239 2240 spin_lock(&inode->i_lock); 2241 for(;;) { 2242 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2243 goto out_zap; 2244 cache = nfs_access_search_rbtree(inode, cred); 2245 err = -ENOENT; 2246 if (cache == NULL) 2247 goto out; 2248 /* Found an entry, is our attribute cache valid? */ 2249 if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) 2250 break; 2251 err = -ECHILD; 2252 if (!may_block) 2253 goto out; 2254 if (!retry) 2255 goto out_zap; 2256 spin_unlock(&inode->i_lock); 2257 err = __nfs_revalidate_inode(NFS_SERVER(inode), inode); 2258 if (err) 2259 return err; 2260 spin_lock(&inode->i_lock); 2261 retry = false; 2262 } 2263 res->cred = cache->cred; 2264 res->mask = cache->mask; 2265 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru); 2266 err = 0; 2267 out: 2268 spin_unlock(&inode->i_lock); 2269 return err; 2270 out_zap: 2271 spin_unlock(&inode->i_lock); 2272 nfs_access_zap_cache(inode); 2273 return -ENOENT; 2274 } 2275 2276 static int nfs_access_get_cached_rcu(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) 2277 { 2278 /* Only check the most recently returned cache entry, 2279 * but do it without locking. 2280 */ 2281 struct nfs_inode *nfsi = NFS_I(inode); 2282 struct nfs_access_entry *cache; 2283 int err = -ECHILD; 2284 struct list_head *lh; 2285 2286 rcu_read_lock(); 2287 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2288 goto out; 2289 lh = rcu_dereference(nfsi->access_cache_entry_lru.prev); 2290 cache = list_entry(lh, struct nfs_access_entry, lru); 2291 if (lh == &nfsi->access_cache_entry_lru || 2292 cred != cache->cred) 2293 cache = NULL; 2294 if (cache == NULL) 2295 goto out; 2296 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) 2297 goto out; 2298 res->cred = cache->cred; 2299 res->mask = cache->mask; 2300 err = 0; 2301 out: 2302 rcu_read_unlock(); 2303 return err; 2304 } 2305 2306 static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) 2307 { 2308 struct nfs_inode *nfsi = NFS_I(inode); 2309 struct rb_root *root_node = &nfsi->access_cache; 2310 struct rb_node **p = &root_node->rb_node; 2311 struct rb_node *parent = NULL; 2312 struct nfs_access_entry *entry; 2313 2314 spin_lock(&inode->i_lock); 2315 while (*p != NULL) { 2316 parent = *p; 2317 entry = rb_entry(parent, struct nfs_access_entry, rb_node); 2318 2319 if (set->cred < entry->cred) 2320 p = &parent->rb_left; 2321 else if (set->cred > entry->cred) 2322 p = &parent->rb_right; 2323 else 2324 goto found; 2325 } 2326 rb_link_node(&set->rb_node, parent, p); 2327 rb_insert_color(&set->rb_node, root_node); 2328 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 2329 spin_unlock(&inode->i_lock); 2330 return; 2331 found: 2332 rb_replace_node(parent, &set->rb_node, root_node); 2333 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 2334 list_del(&entry->lru); 2335 spin_unlock(&inode->i_lock); 2336 nfs_access_free_entry(entry); 2337 } 2338 2339 void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) 2340 { 2341 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); 2342 if (cache == NULL) 2343 return; 2344 RB_CLEAR_NODE(&cache->rb_node); 2345 cache->cred = get_rpccred(set->cred); 2346 cache->mask = set->mask; 2347 2348 /* The above field assignments must be visible 2349 * before this item appears on the lru. We cannot easily 2350 * use rcu_assign_pointer, so just force the memory barrier. 2351 */ 2352 smp_wmb(); 2353 nfs_access_add_rbtree(inode, cache); 2354 2355 /* Update accounting */ 2356 smp_mb__before_atomic(); 2357 atomic_long_inc(&nfs_access_nr_entries); 2358 smp_mb__after_atomic(); 2359 2360 /* Add inode to global LRU list */ 2361 if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) { 2362 spin_lock(&nfs_access_lru_lock); 2363 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2364 list_add_tail(&NFS_I(inode)->access_cache_inode_lru, 2365 &nfs_access_lru_list); 2366 spin_unlock(&nfs_access_lru_lock); 2367 } 2368 nfs_access_cache_enforce_limit(); 2369 } 2370 EXPORT_SYMBOL_GPL(nfs_access_add_cache); 2371 2372 #define NFS_MAY_READ (NFS4_ACCESS_READ) 2373 #define NFS_MAY_WRITE (NFS4_ACCESS_MODIFY | \ 2374 NFS4_ACCESS_EXTEND | \ 2375 NFS4_ACCESS_DELETE) 2376 #define NFS_FILE_MAY_WRITE (NFS4_ACCESS_MODIFY | \ 2377 NFS4_ACCESS_EXTEND) 2378 #define NFS_DIR_MAY_WRITE NFS_MAY_WRITE 2379 #define NFS_MAY_LOOKUP (NFS4_ACCESS_LOOKUP) 2380 #define NFS_MAY_EXECUTE (NFS4_ACCESS_EXECUTE) 2381 static int 2382 nfs_access_calc_mask(u32 access_result, umode_t umode) 2383 { 2384 int mask = 0; 2385 2386 if (access_result & NFS_MAY_READ) 2387 mask |= MAY_READ; 2388 if (S_ISDIR(umode)) { 2389 if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE) 2390 mask |= MAY_WRITE; 2391 if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP) 2392 mask |= MAY_EXEC; 2393 } else if (S_ISREG(umode)) { 2394 if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE) 2395 mask |= MAY_WRITE; 2396 if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE) 2397 mask |= MAY_EXEC; 2398 } else if (access_result & NFS_MAY_WRITE) 2399 mask |= MAY_WRITE; 2400 return mask; 2401 } 2402 2403 void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result) 2404 { 2405 entry->mask = access_result; 2406 } 2407 EXPORT_SYMBOL_GPL(nfs_access_set_mask); 2408 2409 static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) 2410 { 2411 struct nfs_access_entry cache; 2412 bool may_block = (mask & MAY_NOT_BLOCK) == 0; 2413 int cache_mask; 2414 int status; 2415 2416 trace_nfs_access_enter(inode); 2417 2418 status = nfs_access_get_cached_rcu(inode, cred, &cache); 2419 if (status != 0) 2420 status = nfs_access_get_cached(inode, cred, &cache, may_block); 2421 if (status == 0) 2422 goto out_cached; 2423 2424 status = -ECHILD; 2425 if (!may_block) 2426 goto out; 2427 2428 /* Be clever: ask server to check for all possible rights */ 2429 cache.mask = NFS_MAY_LOOKUP | NFS_MAY_EXECUTE 2430 | NFS_MAY_WRITE | NFS_MAY_READ; 2431 cache.cred = cred; 2432 status = NFS_PROTO(inode)->access(inode, &cache); 2433 if (status != 0) { 2434 if (status == -ESTALE) { 2435 nfs_zap_caches(inode); 2436 if (!S_ISDIR(inode->i_mode)) 2437 set_bit(NFS_INO_STALE, &NFS_I(inode)->flags); 2438 } 2439 goto out; 2440 } 2441 nfs_access_add_cache(inode, &cache); 2442 out_cached: 2443 cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode); 2444 if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0) 2445 status = -EACCES; 2446 out: 2447 trace_nfs_access_exit(inode, status); 2448 return status; 2449 } 2450 2451 static int nfs_open_permission_mask(int openflags) 2452 { 2453 int mask = 0; 2454 2455 if (openflags & __FMODE_EXEC) { 2456 /* ONLY check exec rights */ 2457 mask = MAY_EXEC; 2458 } else { 2459 if ((openflags & O_ACCMODE) != O_WRONLY) 2460 mask |= MAY_READ; 2461 if ((openflags & O_ACCMODE) != O_RDONLY) 2462 mask |= MAY_WRITE; 2463 } 2464 2465 return mask; 2466 } 2467 2468 int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags) 2469 { 2470 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); 2471 } 2472 EXPORT_SYMBOL_GPL(nfs_may_open); 2473 2474 static int nfs_execute_ok(struct inode *inode, int mask) 2475 { 2476 struct nfs_server *server = NFS_SERVER(inode); 2477 int ret = 0; 2478 2479 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) { 2480 if (mask & MAY_NOT_BLOCK) 2481 return -ECHILD; 2482 ret = __nfs_revalidate_inode(server, inode); 2483 } 2484 if (ret == 0 && !execute_ok(inode)) 2485 ret = -EACCES; 2486 return ret; 2487 } 2488 2489 int nfs_permission(struct inode *inode, int mask) 2490 { 2491 struct rpc_cred *cred; 2492 int res = 0; 2493 2494 nfs_inc_stats(inode, NFSIOS_VFSACCESS); 2495 2496 if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) 2497 goto out; 2498 /* Is this sys_access() ? */ 2499 if (mask & (MAY_ACCESS | MAY_CHDIR)) 2500 goto force_lookup; 2501 2502 switch (inode->i_mode & S_IFMT) { 2503 case S_IFLNK: 2504 goto out; 2505 case S_IFREG: 2506 if ((mask & MAY_OPEN) && 2507 nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)) 2508 return 0; 2509 break; 2510 case S_IFDIR: 2511 /* 2512 * Optimize away all write operations, since the server 2513 * will check permissions when we perform the op. 2514 */ 2515 if ((mask & MAY_WRITE) && !(mask & MAY_READ)) 2516 goto out; 2517 } 2518 2519 force_lookup: 2520 if (!NFS_PROTO(inode)->access) 2521 goto out_notsup; 2522 2523 /* Always try fast lookups first */ 2524 rcu_read_lock(); 2525 cred = rpc_lookup_cred_nonblock(); 2526 if (!IS_ERR(cred)) 2527 res = nfs_do_access(inode, cred, mask|MAY_NOT_BLOCK); 2528 else 2529 res = PTR_ERR(cred); 2530 rcu_read_unlock(); 2531 if (res == -ECHILD && !(mask & MAY_NOT_BLOCK)) { 2532 /* Fast lookup failed, try the slow way */ 2533 cred = rpc_lookup_cred(); 2534 if (!IS_ERR(cred)) { 2535 res = nfs_do_access(inode, cred, mask); 2536 put_rpccred(cred); 2537 } else 2538 res = PTR_ERR(cred); 2539 } 2540 out: 2541 if (!res && (mask & MAY_EXEC)) 2542 res = nfs_execute_ok(inode, mask); 2543 2544 dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n", 2545 inode->i_sb->s_id, inode->i_ino, mask, res); 2546 return res; 2547 out_notsup: 2548 if (mask & MAY_NOT_BLOCK) 2549 return -ECHILD; 2550 2551 res = nfs_revalidate_inode(NFS_SERVER(inode), inode); 2552 if (res == 0) 2553 res = generic_permission(inode, mask); 2554 goto out; 2555 } 2556 EXPORT_SYMBOL_GPL(nfs_permission); 2557 2558 /* 2559 * Local variables: 2560 * version-control: t 2561 * kept-new-versions: 5 2562 * End: 2563 */ 2564