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/time.h> 21 #include <linux/errno.h> 22 #include <linux/stat.h> 23 #include <linux/fcntl.h> 24 #include <linux/string.h> 25 #include <linux/kernel.h> 26 #include <linux/slab.h> 27 #include <linux/mm.h> 28 #include <linux/sunrpc/clnt.h> 29 #include <linux/nfs_fs.h> 30 #include <linux/nfs_mount.h> 31 #include <linux/pagemap.h> 32 #include <linux/pagevec.h> 33 #include <linux/namei.h> 34 #include <linux/mount.h> 35 #include <linux/sched.h> 36 #include <linux/kmemleak.h> 37 #include <linux/xattr.h> 38 39 #include "delegation.h" 40 #include "iostat.h" 41 #include "internal.h" 42 #include "fscache.h" 43 44 /* #define NFS_DEBUG_VERBOSE 1 */ 45 46 static int nfs_opendir(struct inode *, struct file *); 47 static int nfs_closedir(struct inode *, struct file *); 48 static int nfs_readdir(struct file *, void *, filldir_t); 49 static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *); 50 static int nfs_create(struct inode *, struct dentry *, umode_t, struct nameidata *); 51 static int nfs_mkdir(struct inode *, struct dentry *, umode_t); 52 static int nfs_rmdir(struct inode *, struct dentry *); 53 static int nfs_unlink(struct inode *, struct dentry *); 54 static int nfs_symlink(struct inode *, struct dentry *, const char *); 55 static int nfs_link(struct dentry *, struct inode *, struct dentry *); 56 static int nfs_mknod(struct inode *, struct dentry *, umode_t, dev_t); 57 static int nfs_rename(struct inode *, struct dentry *, 58 struct inode *, struct dentry *); 59 static int nfs_fsync_dir(struct file *, loff_t, loff_t, int); 60 static loff_t nfs_llseek_dir(struct file *, loff_t, int); 61 static void nfs_readdir_clear_array(struct page*); 62 63 const struct file_operations nfs_dir_operations = { 64 .llseek = nfs_llseek_dir, 65 .read = generic_read_dir, 66 .readdir = nfs_readdir, 67 .open = nfs_opendir, 68 .release = nfs_closedir, 69 .fsync = nfs_fsync_dir, 70 }; 71 72 const struct inode_operations nfs_dir_inode_operations = { 73 .create = nfs_create, 74 .lookup = nfs_lookup, 75 .link = nfs_link, 76 .unlink = nfs_unlink, 77 .symlink = nfs_symlink, 78 .mkdir = nfs_mkdir, 79 .rmdir = nfs_rmdir, 80 .mknod = nfs_mknod, 81 .rename = nfs_rename, 82 .permission = nfs_permission, 83 .getattr = nfs_getattr, 84 .setattr = nfs_setattr, 85 }; 86 87 const struct address_space_operations nfs_dir_aops = { 88 .freepage = nfs_readdir_clear_array, 89 }; 90 91 #ifdef CONFIG_NFS_V3 92 const struct inode_operations nfs3_dir_inode_operations = { 93 .create = nfs_create, 94 .lookup = nfs_lookup, 95 .link = nfs_link, 96 .unlink = nfs_unlink, 97 .symlink = nfs_symlink, 98 .mkdir = nfs_mkdir, 99 .rmdir = nfs_rmdir, 100 .mknod = nfs_mknod, 101 .rename = nfs_rename, 102 .permission = nfs_permission, 103 .getattr = nfs_getattr, 104 .setattr = nfs_setattr, 105 .listxattr = nfs3_listxattr, 106 .getxattr = nfs3_getxattr, 107 .setxattr = nfs3_setxattr, 108 .removexattr = nfs3_removexattr, 109 }; 110 #endif /* CONFIG_NFS_V3 */ 111 112 #ifdef CONFIG_NFS_V4 113 114 static int nfs_atomic_open(struct inode *, struct dentry *, 115 struct file *, unsigned, umode_t, 116 int *); 117 const struct inode_operations nfs4_dir_inode_operations = { 118 .create = nfs_create, 119 .lookup = nfs_lookup, 120 .atomic_open = nfs_atomic_open, 121 .link = nfs_link, 122 .unlink = nfs_unlink, 123 .symlink = nfs_symlink, 124 .mkdir = nfs_mkdir, 125 .rmdir = nfs_rmdir, 126 .mknod = nfs_mknod, 127 .rename = nfs_rename, 128 .permission = nfs_permission, 129 .getattr = nfs_getattr, 130 .setattr = nfs_setattr, 131 .getxattr = generic_getxattr, 132 .setxattr = generic_setxattr, 133 .listxattr = generic_listxattr, 134 .removexattr = generic_removexattr, 135 }; 136 137 #endif /* CONFIG_NFS_V4 */ 138 139 static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir, struct rpc_cred *cred) 140 { 141 struct nfs_open_dir_context *ctx; 142 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); 143 if (ctx != NULL) { 144 ctx->duped = 0; 145 ctx->attr_gencount = NFS_I(dir)->attr_gencount; 146 ctx->dir_cookie = 0; 147 ctx->dup_cookie = 0; 148 ctx->cred = get_rpccred(cred); 149 return ctx; 150 } 151 return ERR_PTR(-ENOMEM); 152 } 153 154 static void put_nfs_open_dir_context(struct nfs_open_dir_context *ctx) 155 { 156 put_rpccred(ctx->cred); 157 kfree(ctx); 158 } 159 160 /* 161 * Open file 162 */ 163 static int 164 nfs_opendir(struct inode *inode, struct file *filp) 165 { 166 int res = 0; 167 struct nfs_open_dir_context *ctx; 168 struct rpc_cred *cred; 169 170 dfprintk(FILE, "NFS: open dir(%s/%s)\n", 171 filp->f_path.dentry->d_parent->d_name.name, 172 filp->f_path.dentry->d_name.name); 173 174 nfs_inc_stats(inode, NFSIOS_VFSOPEN); 175 176 cred = rpc_lookup_cred(); 177 if (IS_ERR(cred)) 178 return PTR_ERR(cred); 179 ctx = alloc_nfs_open_dir_context(inode, cred); 180 if (IS_ERR(ctx)) { 181 res = PTR_ERR(ctx); 182 goto out; 183 } 184 filp->private_data = ctx; 185 if (filp->f_path.dentry == filp->f_path.mnt->mnt_root) { 186 /* This is a mountpoint, so d_revalidate will never 187 * have been called, so we need to refresh the 188 * inode (for close-open consistency) ourselves. 189 */ 190 __nfs_revalidate_inode(NFS_SERVER(inode), inode); 191 } 192 out: 193 put_rpccred(cred); 194 return res; 195 } 196 197 static int 198 nfs_closedir(struct inode *inode, struct file *filp) 199 { 200 put_nfs_open_dir_context(filp->private_data); 201 return 0; 202 } 203 204 struct nfs_cache_array_entry { 205 u64 cookie; 206 u64 ino; 207 struct qstr string; 208 unsigned char d_type; 209 }; 210 211 struct nfs_cache_array { 212 int size; 213 int eof_index; 214 u64 last_cookie; 215 struct nfs_cache_array_entry array[0]; 216 }; 217 218 typedef int (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, int); 219 typedef struct { 220 struct file *file; 221 struct page *page; 222 unsigned long page_index; 223 u64 *dir_cookie; 224 u64 last_cookie; 225 loff_t current_index; 226 decode_dirent_t decode; 227 228 unsigned long timestamp; 229 unsigned long gencount; 230 unsigned int cache_entry_index; 231 unsigned int plus:1; 232 unsigned int eof:1; 233 } nfs_readdir_descriptor_t; 234 235 /* 236 * The caller is responsible for calling nfs_readdir_release_array(page) 237 */ 238 static 239 struct nfs_cache_array *nfs_readdir_get_array(struct page *page) 240 { 241 void *ptr; 242 if (page == NULL) 243 return ERR_PTR(-EIO); 244 ptr = kmap(page); 245 if (ptr == NULL) 246 return ERR_PTR(-ENOMEM); 247 return ptr; 248 } 249 250 static 251 void nfs_readdir_release_array(struct page *page) 252 { 253 kunmap(page); 254 } 255 256 /* 257 * we are freeing strings created by nfs_add_to_readdir_array() 258 */ 259 static 260 void nfs_readdir_clear_array(struct page *page) 261 { 262 struct nfs_cache_array *array; 263 int i; 264 265 array = kmap_atomic(page); 266 for (i = 0; i < array->size; i++) 267 kfree(array->array[i].string.name); 268 kunmap_atomic(array); 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 277 int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int len) 278 { 279 string->len = len; 280 string->name = kmemdup(name, len, GFP_KERNEL); 281 if (string->name == NULL) 282 return -ENOMEM; 283 /* 284 * Avoid a kmemleak false positive. The pointer to the name is stored 285 * in a page cache page which kmemleak does not scan. 286 */ 287 kmemleak_not_leak(string->name); 288 string->hash = full_name_hash(name, len); 289 return 0; 290 } 291 292 static 293 int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page) 294 { 295 struct nfs_cache_array *array = nfs_readdir_get_array(page); 296 struct nfs_cache_array_entry *cache_entry; 297 int ret; 298 299 if (IS_ERR(array)) 300 return PTR_ERR(array); 301 302 cache_entry = &array->array[array->size]; 303 304 /* Check that this entry lies within the page bounds */ 305 ret = -ENOSPC; 306 if ((char *)&cache_entry[1] - (char *)page_address(page) > PAGE_SIZE) 307 goto out; 308 309 cache_entry->cookie = entry->prev_cookie; 310 cache_entry->ino = entry->ino; 311 cache_entry->d_type = entry->d_type; 312 ret = nfs_readdir_make_qstr(&cache_entry->string, entry->name, entry->len); 313 if (ret) 314 goto out; 315 array->last_cookie = entry->cookie; 316 array->size++; 317 if (entry->eof != 0) 318 array->eof_index = array->size; 319 out: 320 nfs_readdir_release_array(page); 321 return ret; 322 } 323 324 static 325 int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc) 326 { 327 loff_t diff = desc->file->f_pos - desc->current_index; 328 unsigned int index; 329 330 if (diff < 0) 331 goto out_eof; 332 if (diff >= array->size) { 333 if (array->eof_index >= 0) 334 goto out_eof; 335 return -EAGAIN; 336 } 337 338 index = (unsigned int)diff; 339 *desc->dir_cookie = array->array[index].cookie; 340 desc->cache_entry_index = index; 341 return 0; 342 out_eof: 343 desc->eof = 1; 344 return -EBADCOOKIE; 345 } 346 347 static 348 int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc) 349 { 350 int i; 351 loff_t new_pos; 352 int status = -EAGAIN; 353 354 for (i = 0; i < array->size; i++) { 355 if (array->array[i].cookie == *desc->dir_cookie) { 356 struct nfs_inode *nfsi = NFS_I(desc->file->f_path.dentry->d_inode); 357 struct nfs_open_dir_context *ctx = desc->file->private_data; 358 359 new_pos = desc->current_index + i; 360 if (ctx->attr_gencount != nfsi->attr_gencount 361 || (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))) { 362 ctx->duped = 0; 363 ctx->attr_gencount = nfsi->attr_gencount; 364 } else if (new_pos < desc->file->f_pos) { 365 if (ctx->duped > 0 366 && ctx->dup_cookie == *desc->dir_cookie) { 367 if (printk_ratelimit()) { 368 pr_notice("NFS: directory %s/%s contains a readdir loop." 369 "Please contact your server vendor. " 370 "The file: %s has duplicate cookie %llu\n", 371 desc->file->f_dentry->d_parent->d_name.name, 372 desc->file->f_dentry->d_name.name, 373 array->array[i].string.name, 374 *desc->dir_cookie); 375 } 376 status = -ELOOP; 377 goto out; 378 } 379 ctx->dup_cookie = *desc->dir_cookie; 380 ctx->duped = -1; 381 } 382 desc->file->f_pos = new_pos; 383 desc->cache_entry_index = i; 384 return 0; 385 } 386 } 387 if (array->eof_index >= 0) { 388 status = -EBADCOOKIE; 389 if (*desc->dir_cookie == array->last_cookie) 390 desc->eof = 1; 391 } 392 out: 393 return status; 394 } 395 396 static 397 int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc) 398 { 399 struct nfs_cache_array *array; 400 int status; 401 402 array = nfs_readdir_get_array(desc->page); 403 if (IS_ERR(array)) { 404 status = PTR_ERR(array); 405 goto out; 406 } 407 408 if (*desc->dir_cookie == 0) 409 status = nfs_readdir_search_for_pos(array, desc); 410 else 411 status = nfs_readdir_search_for_cookie(array, desc); 412 413 if (status == -EAGAIN) { 414 desc->last_cookie = array->last_cookie; 415 desc->current_index += array->size; 416 desc->page_index++; 417 } 418 nfs_readdir_release_array(desc->page); 419 out: 420 return status; 421 } 422 423 /* Fill a page with xdr information before transferring to the cache page */ 424 static 425 int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc, 426 struct nfs_entry *entry, struct file *file, struct inode *inode) 427 { 428 struct nfs_open_dir_context *ctx = file->private_data; 429 struct rpc_cred *cred = ctx->cred; 430 unsigned long timestamp, gencount; 431 int error; 432 433 again: 434 timestamp = jiffies; 435 gencount = nfs_inc_attr_generation_counter(); 436 error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, entry->cookie, pages, 437 NFS_SERVER(inode)->dtsize, desc->plus); 438 if (error < 0) { 439 /* We requested READDIRPLUS, but the server doesn't grok it */ 440 if (error == -ENOTSUPP && desc->plus) { 441 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; 442 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 443 desc->plus = 0; 444 goto again; 445 } 446 goto error; 447 } 448 desc->timestamp = timestamp; 449 desc->gencount = gencount; 450 error: 451 return error; 452 } 453 454 static int xdr_decode(nfs_readdir_descriptor_t *desc, 455 struct nfs_entry *entry, struct xdr_stream *xdr) 456 { 457 int error; 458 459 error = desc->decode(xdr, entry, desc->plus); 460 if (error) 461 return error; 462 entry->fattr->time_start = desc->timestamp; 463 entry->fattr->gencount = desc->gencount; 464 return 0; 465 } 466 467 static 468 int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) 469 { 470 if (dentry->d_inode == NULL) 471 goto different; 472 if (nfs_compare_fh(entry->fh, NFS_FH(dentry->d_inode)) != 0) 473 goto different; 474 return 1; 475 different: 476 return 0; 477 } 478 479 static 480 bool nfs_use_readdirplus(struct inode *dir, struct file *filp) 481 { 482 if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS)) 483 return false; 484 if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags)) 485 return true; 486 if (filp->f_pos == 0) 487 return true; 488 return false; 489 } 490 491 /* 492 * This function is called by the lookup code to request the use of 493 * readdirplus to accelerate any future lookups in the same 494 * directory. 495 */ 496 static 497 void nfs_advise_use_readdirplus(struct inode *dir) 498 { 499 set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags); 500 } 501 502 static 503 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry) 504 { 505 struct qstr filename = QSTR_INIT(entry->name, entry->len); 506 struct dentry *dentry; 507 struct dentry *alias; 508 struct inode *dir = parent->d_inode; 509 struct inode *inode; 510 511 if (filename.name[0] == '.') { 512 if (filename.len == 1) 513 return; 514 if (filename.len == 2 && filename.name[1] == '.') 515 return; 516 } 517 filename.hash = full_name_hash(filename.name, filename.len); 518 519 dentry = d_lookup(parent, &filename); 520 if (dentry != NULL) { 521 if (nfs_same_file(dentry, entry)) { 522 nfs_refresh_inode(dentry->d_inode, entry->fattr); 523 goto out; 524 } else { 525 d_drop(dentry); 526 dput(dentry); 527 } 528 } 529 530 dentry = d_alloc(parent, &filename); 531 if (dentry == NULL) 532 return; 533 534 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); 535 if (IS_ERR(inode)) 536 goto out; 537 538 alias = d_materialise_unique(dentry, inode); 539 if (IS_ERR(alias)) 540 goto out; 541 else if (alias) { 542 nfs_set_verifier(alias, nfs_save_change_attribute(dir)); 543 dput(alias); 544 } else 545 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 546 547 out: 548 dput(dentry); 549 } 550 551 /* Perform conversion from xdr to cache array */ 552 static 553 int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, 554 struct page **xdr_pages, struct page *page, unsigned int buflen) 555 { 556 struct xdr_stream stream; 557 struct xdr_buf buf; 558 struct page *scratch; 559 struct nfs_cache_array *array; 560 unsigned int count = 0; 561 int status; 562 563 scratch = alloc_page(GFP_KERNEL); 564 if (scratch == NULL) 565 return -ENOMEM; 566 567 xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen); 568 xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE); 569 570 do { 571 status = xdr_decode(desc, entry, &stream); 572 if (status != 0) { 573 if (status == -EAGAIN) 574 status = 0; 575 break; 576 } 577 578 count++; 579 580 if (desc->plus != 0) 581 nfs_prime_dcache(desc->file->f_path.dentry, entry); 582 583 status = nfs_readdir_add_to_array(entry, page); 584 if (status != 0) 585 break; 586 } while (!entry->eof); 587 588 if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) { 589 array = nfs_readdir_get_array(page); 590 if (!IS_ERR(array)) { 591 array->eof_index = array->size; 592 status = 0; 593 nfs_readdir_release_array(page); 594 } else 595 status = PTR_ERR(array); 596 } 597 598 put_page(scratch); 599 return status; 600 } 601 602 static 603 void nfs_readdir_free_pagearray(struct page **pages, unsigned int npages) 604 { 605 unsigned int i; 606 for (i = 0; i < npages; i++) 607 put_page(pages[i]); 608 } 609 610 static 611 void nfs_readdir_free_large_page(void *ptr, struct page **pages, 612 unsigned int npages) 613 { 614 nfs_readdir_free_pagearray(pages, npages); 615 } 616 617 /* 618 * nfs_readdir_large_page will allocate pages that must be freed with a call 619 * to nfs_readdir_free_large_page 620 */ 621 static 622 int nfs_readdir_large_page(struct page **pages, unsigned int npages) 623 { 624 unsigned int i; 625 626 for (i = 0; i < npages; i++) { 627 struct page *page = alloc_page(GFP_KERNEL); 628 if (page == NULL) 629 goto out_freepages; 630 pages[i] = page; 631 } 632 return 0; 633 634 out_freepages: 635 nfs_readdir_free_pagearray(pages, i); 636 return -ENOMEM; 637 } 638 639 static 640 int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode) 641 { 642 struct page *pages[NFS_MAX_READDIR_PAGES]; 643 void *pages_ptr = NULL; 644 struct nfs_entry entry; 645 struct file *file = desc->file; 646 struct nfs_cache_array *array; 647 int status = -ENOMEM; 648 unsigned int array_size = ARRAY_SIZE(pages); 649 650 entry.prev_cookie = 0; 651 entry.cookie = desc->last_cookie; 652 entry.eof = 0; 653 entry.fh = nfs_alloc_fhandle(); 654 entry.fattr = nfs_alloc_fattr(); 655 entry.server = NFS_SERVER(inode); 656 if (entry.fh == NULL || entry.fattr == NULL) 657 goto out; 658 659 array = nfs_readdir_get_array(page); 660 if (IS_ERR(array)) { 661 status = PTR_ERR(array); 662 goto out; 663 } 664 memset(array, 0, sizeof(struct nfs_cache_array)); 665 array->eof_index = -1; 666 667 status = nfs_readdir_large_page(pages, array_size); 668 if (status < 0) 669 goto out_release_array; 670 do { 671 unsigned int pglen; 672 status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode); 673 674 if (status < 0) 675 break; 676 pglen = status; 677 status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen); 678 if (status < 0) { 679 if (status == -ENOSPC) 680 status = 0; 681 break; 682 } 683 } while (array->eof_index < 0); 684 685 nfs_readdir_free_large_page(pages_ptr, pages, array_size); 686 out_release_array: 687 nfs_readdir_release_array(page); 688 out: 689 nfs_free_fattr(entry.fattr); 690 nfs_free_fhandle(entry.fh); 691 return status; 692 } 693 694 /* 695 * Now we cache directories properly, by converting xdr information 696 * to an array that can be used for lookups later. This results in 697 * fewer cache pages, since we can store more information on each page. 698 * We only need to convert from xdr once so future lookups are much simpler 699 */ 700 static 701 int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page) 702 { 703 struct inode *inode = desc->file->f_path.dentry->d_inode; 704 int ret; 705 706 ret = nfs_readdir_xdr_to_array(desc, page, inode); 707 if (ret < 0) 708 goto error; 709 SetPageUptodate(page); 710 711 if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) { 712 /* Should never happen */ 713 nfs_zap_mapping(inode, inode->i_mapping); 714 } 715 unlock_page(page); 716 return 0; 717 error: 718 unlock_page(page); 719 return ret; 720 } 721 722 static 723 void cache_page_release(nfs_readdir_descriptor_t *desc) 724 { 725 if (!desc->page->mapping) 726 nfs_readdir_clear_array(desc->page); 727 page_cache_release(desc->page); 728 desc->page = NULL; 729 } 730 731 static 732 struct page *get_cache_page(nfs_readdir_descriptor_t *desc) 733 { 734 return read_cache_page(desc->file->f_path.dentry->d_inode->i_mapping, 735 desc->page_index, (filler_t *)nfs_readdir_filler, desc); 736 } 737 738 /* 739 * Returns 0 if desc->dir_cookie was found on page desc->page_index 740 */ 741 static 742 int find_cache_page(nfs_readdir_descriptor_t *desc) 743 { 744 int res; 745 746 desc->page = get_cache_page(desc); 747 if (IS_ERR(desc->page)) 748 return PTR_ERR(desc->page); 749 750 res = nfs_readdir_search_array(desc); 751 if (res != 0) 752 cache_page_release(desc); 753 return res; 754 } 755 756 /* Search for desc->dir_cookie from the beginning of the page cache */ 757 static inline 758 int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) 759 { 760 int res; 761 762 if (desc->page_index == 0) { 763 desc->current_index = 0; 764 desc->last_cookie = 0; 765 } 766 do { 767 res = find_cache_page(desc); 768 } while (res == -EAGAIN); 769 return res; 770 } 771 772 /* 773 * Once we've found the start of the dirent within a page: fill 'er up... 774 */ 775 static 776 int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent, 777 filldir_t filldir) 778 { 779 struct file *file = desc->file; 780 int i = 0; 781 int res = 0; 782 struct nfs_cache_array *array = NULL; 783 struct nfs_open_dir_context *ctx = file->private_data; 784 785 array = nfs_readdir_get_array(desc->page); 786 if (IS_ERR(array)) { 787 res = PTR_ERR(array); 788 goto out; 789 } 790 791 for (i = desc->cache_entry_index; i < array->size; i++) { 792 struct nfs_cache_array_entry *ent; 793 794 ent = &array->array[i]; 795 if (filldir(dirent, ent->string.name, ent->string.len, 796 file->f_pos, nfs_compat_user_ino64(ent->ino), 797 ent->d_type) < 0) { 798 desc->eof = 1; 799 break; 800 } 801 file->f_pos++; 802 if (i < (array->size-1)) 803 *desc->dir_cookie = array->array[i+1].cookie; 804 else 805 *desc->dir_cookie = array->last_cookie; 806 if (ctx->duped != 0) 807 ctx->duped = 1; 808 } 809 if (array->eof_index >= 0) 810 desc->eof = 1; 811 812 nfs_readdir_release_array(desc->page); 813 out: 814 cache_page_release(desc); 815 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", 816 (unsigned long long)*desc->dir_cookie, res); 817 return res; 818 } 819 820 /* 821 * If we cannot find a cookie in our cache, we suspect that this is 822 * because it points to a deleted file, so we ask the server to return 823 * whatever it thinks is the next entry. We then feed this to filldir. 824 * If all goes well, we should then be able to find our way round the 825 * cache on the next call to readdir_search_pagecache(); 826 * 827 * NOTE: we cannot add the anonymous page to the pagecache because 828 * the data it contains might not be page aligned. Besides, 829 * we should already have a complete representation of the 830 * directory in the page cache by the time we get here. 831 */ 832 static inline 833 int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent, 834 filldir_t filldir) 835 { 836 struct page *page = NULL; 837 int status; 838 struct inode *inode = desc->file->f_path.dentry->d_inode; 839 struct nfs_open_dir_context *ctx = desc->file->private_data; 840 841 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n", 842 (unsigned long long)*desc->dir_cookie); 843 844 page = alloc_page(GFP_HIGHUSER); 845 if (!page) { 846 status = -ENOMEM; 847 goto out; 848 } 849 850 desc->page_index = 0; 851 desc->last_cookie = *desc->dir_cookie; 852 desc->page = page; 853 ctx->duped = 0; 854 855 status = nfs_readdir_xdr_to_array(desc, page, inode); 856 if (status < 0) 857 goto out_release; 858 859 status = nfs_do_filldir(desc, dirent, filldir); 860 861 out: 862 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", 863 __func__, status); 864 return status; 865 out_release: 866 cache_page_release(desc); 867 goto out; 868 } 869 870 /* The file offset position represents the dirent entry number. A 871 last cookie cache takes care of the common case of reading the 872 whole directory. 873 */ 874 static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir) 875 { 876 struct dentry *dentry = filp->f_path.dentry; 877 struct inode *inode = dentry->d_inode; 878 nfs_readdir_descriptor_t my_desc, 879 *desc = &my_desc; 880 struct nfs_open_dir_context *dir_ctx = filp->private_data; 881 int res; 882 883 dfprintk(FILE, "NFS: readdir(%s/%s) starting at cookie %llu\n", 884 dentry->d_parent->d_name.name, dentry->d_name.name, 885 (long long)filp->f_pos); 886 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); 887 888 /* 889 * filp->f_pos points to the dirent entry number. 890 * *desc->dir_cookie has the cookie for the next entry. We have 891 * to either find the entry with the appropriate number or 892 * revalidate the cookie. 893 */ 894 memset(desc, 0, sizeof(*desc)); 895 896 desc->file = filp; 897 desc->dir_cookie = &dir_ctx->dir_cookie; 898 desc->decode = NFS_PROTO(inode)->decode_dirent; 899 desc->plus = nfs_use_readdirplus(inode, filp) ? 1 : 0; 900 901 nfs_block_sillyrename(dentry); 902 res = nfs_revalidate_mapping(inode, filp->f_mapping); 903 if (res < 0) 904 goto out; 905 906 do { 907 res = readdir_search_pagecache(desc); 908 909 if (res == -EBADCOOKIE) { 910 res = 0; 911 /* This means either end of directory */ 912 if (*desc->dir_cookie && desc->eof == 0) { 913 /* Or that the server has 'lost' a cookie */ 914 res = uncached_readdir(desc, dirent, filldir); 915 if (res == 0) 916 continue; 917 } 918 break; 919 } 920 if (res == -ETOOSMALL && desc->plus) { 921 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 922 nfs_zap_caches(inode); 923 desc->page_index = 0; 924 desc->plus = 0; 925 desc->eof = 0; 926 continue; 927 } 928 if (res < 0) 929 break; 930 931 res = nfs_do_filldir(desc, dirent, filldir); 932 if (res < 0) 933 break; 934 } while (!desc->eof); 935 out: 936 nfs_unblock_sillyrename(dentry); 937 if (res > 0) 938 res = 0; 939 dfprintk(FILE, "NFS: readdir(%s/%s) returns %d\n", 940 dentry->d_parent->d_name.name, dentry->d_name.name, 941 res); 942 return res; 943 } 944 945 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin) 946 { 947 struct dentry *dentry = filp->f_path.dentry; 948 struct inode *inode = dentry->d_inode; 949 struct nfs_open_dir_context *dir_ctx = filp->private_data; 950 951 dfprintk(FILE, "NFS: llseek dir(%s/%s, %lld, %d)\n", 952 dentry->d_parent->d_name.name, 953 dentry->d_name.name, 954 offset, origin); 955 956 mutex_lock(&inode->i_mutex); 957 switch (origin) { 958 case 1: 959 offset += filp->f_pos; 960 case 0: 961 if (offset >= 0) 962 break; 963 default: 964 offset = -EINVAL; 965 goto out; 966 } 967 if (offset != filp->f_pos) { 968 filp->f_pos = offset; 969 dir_ctx->dir_cookie = 0; 970 dir_ctx->duped = 0; 971 } 972 out: 973 mutex_unlock(&inode->i_mutex); 974 return offset; 975 } 976 977 /* 978 * All directory operations under NFS are synchronous, so fsync() 979 * is a dummy operation. 980 */ 981 static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end, 982 int datasync) 983 { 984 struct dentry *dentry = filp->f_path.dentry; 985 struct inode *inode = dentry->d_inode; 986 987 dfprintk(FILE, "NFS: fsync dir(%s/%s) datasync %d\n", 988 dentry->d_parent->d_name.name, dentry->d_name.name, 989 datasync); 990 991 mutex_lock(&inode->i_mutex); 992 nfs_inc_stats(dentry->d_inode, NFSIOS_VFSFSYNC); 993 mutex_unlock(&inode->i_mutex); 994 return 0; 995 } 996 997 /** 998 * nfs_force_lookup_revalidate - Mark the directory as having changed 999 * @dir - pointer to directory inode 1000 * 1001 * This forces the revalidation code in nfs_lookup_revalidate() to do a 1002 * full lookup on all child dentries of 'dir' whenever a change occurs 1003 * on the server that might have invalidated our dcache. 1004 * 1005 * The caller should be holding dir->i_lock 1006 */ 1007 void nfs_force_lookup_revalidate(struct inode *dir) 1008 { 1009 NFS_I(dir)->cache_change_attribute++; 1010 } 1011 1012 /* 1013 * A check for whether or not the parent directory has changed. 1014 * In the case it has, we assume that the dentries are untrustworthy 1015 * and may need to be looked up again. 1016 */ 1017 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry) 1018 { 1019 if (IS_ROOT(dentry)) 1020 return 1; 1021 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE) 1022 return 0; 1023 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 1024 return 0; 1025 /* Revalidate nfsi->cache_change_attribute before we declare a match */ 1026 if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) 1027 return 0; 1028 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 1029 return 0; 1030 return 1; 1031 } 1032 1033 /* 1034 * Return the intent data that applies to this particular path component 1035 * 1036 * Note that the current set of intents only apply to the very last 1037 * component of the path and none of them is set before that last 1038 * component. 1039 */ 1040 static inline unsigned int nfs_lookup_check_intent(unsigned int flags, 1041 unsigned int mask) 1042 { 1043 return flags & mask; 1044 } 1045 1046 /* 1047 * Use intent information to check whether or not we're going to do 1048 * an O_EXCL create using this path component. 1049 */ 1050 static int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd) 1051 { 1052 if (NFS_PROTO(dir)->version == 2) 1053 return 0; 1054 return nd && nfs_lookup_check_intent(nd->flags, LOOKUP_EXCL); 1055 } 1056 1057 /* 1058 * Inode and filehandle revalidation for lookups. 1059 * 1060 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, 1061 * or if the intent information indicates that we're about to open this 1062 * particular file and the "nocto" mount flag is not set. 1063 * 1064 */ 1065 static inline 1066 int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd) 1067 { 1068 struct nfs_server *server = NFS_SERVER(inode); 1069 1070 if (IS_AUTOMOUNT(inode)) 1071 return 0; 1072 /* VFS wants an on-the-wire revalidation */ 1073 if (nd->flags & LOOKUP_REVAL) 1074 goto out_force; 1075 /* This is an open(2) */ 1076 if (nfs_lookup_check_intent(nd->flags, LOOKUP_OPEN) != 0 && 1077 !(server->flags & NFS_MOUNT_NOCTO) && 1078 (S_ISREG(inode->i_mode) || 1079 S_ISDIR(inode->i_mode))) 1080 goto out_force; 1081 return 0; 1082 out_force: 1083 return __nfs_revalidate_inode(server, inode); 1084 } 1085 1086 /* 1087 * We judge how long we want to trust negative 1088 * dentries by looking at the parent inode mtime. 1089 * 1090 * If parent mtime has changed, we revalidate, else we wait for a 1091 * period corresponding to the parent's attribute cache timeout value. 1092 */ 1093 static inline 1094 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 1095 struct nameidata *nd) 1096 { 1097 /* Don't revalidate a negative dentry if we're creating a new file */ 1098 if (nd != NULL && nfs_lookup_check_intent(nd->flags, LOOKUP_CREATE) != 0) 1099 return 0; 1100 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) 1101 return 1; 1102 return !nfs_check_verifier(dir, dentry); 1103 } 1104 1105 /* 1106 * This is called every time the dcache has a lookup hit, 1107 * and we should check whether we can really trust that 1108 * lookup. 1109 * 1110 * NOTE! The hit can be a negative hit too, don't assume 1111 * we have an inode! 1112 * 1113 * If the parent directory is seen to have changed, we throw out the 1114 * cached dentry and do a new lookup. 1115 */ 1116 static int nfs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd) 1117 { 1118 struct inode *dir; 1119 struct inode *inode; 1120 struct dentry *parent; 1121 struct nfs_fh *fhandle = NULL; 1122 struct nfs_fattr *fattr = NULL; 1123 int error; 1124 1125 if (nd->flags & LOOKUP_RCU) 1126 return -ECHILD; 1127 1128 parent = dget_parent(dentry); 1129 dir = parent->d_inode; 1130 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); 1131 inode = dentry->d_inode; 1132 1133 if (!inode) { 1134 if (nfs_neg_need_reval(dir, dentry, nd)) 1135 goto out_bad; 1136 goto out_valid_noent; 1137 } 1138 1139 if (is_bad_inode(inode)) { 1140 dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n", 1141 __func__, dentry->d_parent->d_name.name, 1142 dentry->d_name.name); 1143 goto out_bad; 1144 } 1145 1146 if (nfs_have_delegation(inode, FMODE_READ)) 1147 goto out_set_verifier; 1148 1149 /* Force a full look up iff the parent directory has changed */ 1150 if (!nfs_is_exclusive_create(dir, nd) && nfs_check_verifier(dir, dentry)) { 1151 if (nfs_lookup_verify_inode(inode, nd)) 1152 goto out_zap_parent; 1153 goto out_valid; 1154 } 1155 1156 if (NFS_STALE(inode)) 1157 goto out_bad; 1158 1159 error = -ENOMEM; 1160 fhandle = nfs_alloc_fhandle(); 1161 fattr = nfs_alloc_fattr(); 1162 if (fhandle == NULL || fattr == NULL) 1163 goto out_error; 1164 1165 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); 1166 if (error) 1167 goto out_bad; 1168 if (nfs_compare_fh(NFS_FH(inode), fhandle)) 1169 goto out_bad; 1170 if ((error = nfs_refresh_inode(inode, fattr)) != 0) 1171 goto out_bad; 1172 1173 nfs_free_fattr(fattr); 1174 nfs_free_fhandle(fhandle); 1175 out_set_verifier: 1176 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1177 out_valid: 1178 /* Success: notify readdir to use READDIRPLUS */ 1179 nfs_advise_use_readdirplus(dir); 1180 out_valid_noent: 1181 dput(parent); 1182 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n", 1183 __func__, dentry->d_parent->d_name.name, 1184 dentry->d_name.name); 1185 return 1; 1186 out_zap_parent: 1187 nfs_zap_caches(dir); 1188 out_bad: 1189 nfs_mark_for_revalidate(dir); 1190 if (inode && S_ISDIR(inode->i_mode)) { 1191 /* Purge readdir caches. */ 1192 nfs_zap_caches(inode); 1193 /* If we have submounts, don't unhash ! */ 1194 if (have_submounts(dentry)) 1195 goto out_valid; 1196 if (dentry->d_flags & DCACHE_DISCONNECTED) 1197 goto out_valid; 1198 shrink_dcache_parent(dentry); 1199 } 1200 d_drop(dentry); 1201 nfs_free_fattr(fattr); 1202 nfs_free_fhandle(fhandle); 1203 dput(parent); 1204 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n", 1205 __func__, dentry->d_parent->d_name.name, 1206 dentry->d_name.name); 1207 return 0; 1208 out_error: 1209 nfs_free_fattr(fattr); 1210 nfs_free_fhandle(fhandle); 1211 dput(parent); 1212 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) lookup returned error %d\n", 1213 __func__, dentry->d_parent->d_name.name, 1214 dentry->d_name.name, error); 1215 return error; 1216 } 1217 1218 /* 1219 * This is called from dput() when d_count is going to 0. 1220 */ 1221 static int nfs_dentry_delete(const struct dentry *dentry) 1222 { 1223 dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n", 1224 dentry->d_parent->d_name.name, dentry->d_name.name, 1225 dentry->d_flags); 1226 1227 /* Unhash any dentry with a stale inode */ 1228 if (dentry->d_inode != NULL && NFS_STALE(dentry->d_inode)) 1229 return 1; 1230 1231 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1232 /* Unhash it, so that ->d_iput() would be called */ 1233 return 1; 1234 } 1235 if (!(dentry->d_sb->s_flags & MS_ACTIVE)) { 1236 /* Unhash it, so that ancestors of killed async unlink 1237 * files will be cleaned up during umount */ 1238 return 1; 1239 } 1240 return 0; 1241 1242 } 1243 1244 static void nfs_drop_nlink(struct inode *inode) 1245 { 1246 spin_lock(&inode->i_lock); 1247 if (inode->i_nlink > 0) 1248 drop_nlink(inode); 1249 spin_unlock(&inode->i_lock); 1250 } 1251 1252 /* 1253 * Called when the dentry loses inode. 1254 * We use it to clean up silly-renamed files. 1255 */ 1256 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) 1257 { 1258 if (S_ISDIR(inode->i_mode)) 1259 /* drop any readdir cache as it could easily be old */ 1260 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA; 1261 1262 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1263 drop_nlink(inode); 1264 nfs_complete_unlink(dentry, inode); 1265 } 1266 iput(inode); 1267 } 1268 1269 static void nfs_d_release(struct dentry *dentry) 1270 { 1271 /* free cached devname value, if it survived that far */ 1272 if (unlikely(dentry->d_fsdata)) { 1273 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 1274 WARN_ON(1); 1275 else 1276 kfree(dentry->d_fsdata); 1277 } 1278 } 1279 1280 const struct dentry_operations nfs_dentry_operations = { 1281 .d_revalidate = nfs_lookup_revalidate, 1282 .d_delete = nfs_dentry_delete, 1283 .d_iput = nfs_dentry_iput, 1284 .d_automount = nfs_d_automount, 1285 .d_release = nfs_d_release, 1286 }; 1287 1288 static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) 1289 { 1290 struct dentry *res; 1291 struct dentry *parent; 1292 struct inode *inode = NULL; 1293 struct nfs_fh *fhandle = NULL; 1294 struct nfs_fattr *fattr = NULL; 1295 int error; 1296 1297 dfprintk(VFS, "NFS: lookup(%s/%s)\n", 1298 dentry->d_parent->d_name.name, dentry->d_name.name); 1299 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); 1300 1301 res = ERR_PTR(-ENAMETOOLONG); 1302 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 1303 goto out; 1304 1305 /* 1306 * If we're doing an exclusive create, optimize away the lookup 1307 * but don't hash the dentry. 1308 */ 1309 if (nfs_is_exclusive_create(dir, nd)) { 1310 d_instantiate(dentry, NULL); 1311 res = NULL; 1312 goto out; 1313 } 1314 1315 res = ERR_PTR(-ENOMEM); 1316 fhandle = nfs_alloc_fhandle(); 1317 fattr = nfs_alloc_fattr(); 1318 if (fhandle == NULL || fattr == NULL) 1319 goto out; 1320 1321 parent = dentry->d_parent; 1322 /* Protect against concurrent sillydeletes */ 1323 nfs_block_sillyrename(parent); 1324 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); 1325 if (error == -ENOENT) 1326 goto no_entry; 1327 if (error < 0) { 1328 res = ERR_PTR(error); 1329 goto out_unblock_sillyrename; 1330 } 1331 inode = nfs_fhget(dentry->d_sb, fhandle, fattr); 1332 res = ERR_CAST(inode); 1333 if (IS_ERR(res)) 1334 goto out_unblock_sillyrename; 1335 1336 /* Success: notify readdir to use READDIRPLUS */ 1337 nfs_advise_use_readdirplus(dir); 1338 1339 no_entry: 1340 res = d_materialise_unique(dentry, inode); 1341 if (res != NULL) { 1342 if (IS_ERR(res)) 1343 goto out_unblock_sillyrename; 1344 dentry = res; 1345 } 1346 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1347 out_unblock_sillyrename: 1348 nfs_unblock_sillyrename(parent); 1349 out: 1350 nfs_free_fattr(fattr); 1351 nfs_free_fhandle(fhandle); 1352 return res; 1353 } 1354 1355 #ifdef CONFIG_NFS_V4 1356 static int nfs4_lookup_revalidate(struct dentry *, struct nameidata *); 1357 1358 const struct dentry_operations nfs4_dentry_operations = { 1359 .d_revalidate = nfs4_lookup_revalidate, 1360 .d_delete = nfs_dentry_delete, 1361 .d_iput = nfs_dentry_iput, 1362 .d_automount = nfs_d_automount, 1363 .d_release = nfs_d_release, 1364 }; 1365 1366 static fmode_t flags_to_mode(int flags) 1367 { 1368 fmode_t res = (__force fmode_t)flags & FMODE_EXEC; 1369 if ((flags & O_ACCMODE) != O_WRONLY) 1370 res |= FMODE_READ; 1371 if ((flags & O_ACCMODE) != O_RDONLY) 1372 res |= FMODE_WRITE; 1373 return res; 1374 } 1375 1376 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags) 1377 { 1378 return alloc_nfs_open_context(dentry, flags_to_mode(open_flags)); 1379 } 1380 1381 static int do_open(struct inode *inode, struct file *filp) 1382 { 1383 nfs_fscache_set_inode_cookie(inode, filp); 1384 return 0; 1385 } 1386 1387 static int nfs_finish_open(struct nfs_open_context *ctx, 1388 struct dentry *dentry, 1389 struct file *file, unsigned open_flags, 1390 int *opened) 1391 { 1392 int err; 1393 1394 if (ctx->dentry != dentry) { 1395 dput(ctx->dentry); 1396 ctx->dentry = dget(dentry); 1397 } 1398 1399 /* If the open_intent is for execute, we have an extra check to make */ 1400 if (ctx->mode & FMODE_EXEC) { 1401 err = nfs_may_open(dentry->d_inode, ctx->cred, open_flags); 1402 if (err < 0) 1403 goto out; 1404 } 1405 1406 err = finish_open(file, dentry, do_open, opened); 1407 if (err) 1408 goto out; 1409 nfs_file_set_open_context(file, ctx); 1410 1411 out: 1412 put_nfs_open_context(ctx); 1413 return err; 1414 } 1415 1416 static int nfs_atomic_open(struct inode *dir, struct dentry *dentry, 1417 struct file *file, unsigned open_flags, 1418 umode_t mode, int *opened) 1419 { 1420 struct nfs_open_context *ctx; 1421 struct dentry *res; 1422 struct iattr attr = { .ia_valid = ATTR_OPEN }; 1423 struct inode *inode; 1424 int err; 1425 1426 /* Expect a negative dentry */ 1427 BUG_ON(dentry->d_inode); 1428 1429 dfprintk(VFS, "NFS: atomic_open(%s/%ld), %s\n", 1430 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1431 1432 /* NFS only supports OPEN on regular files */ 1433 if ((open_flags & O_DIRECTORY)) { 1434 if (!d_unhashed(dentry)) { 1435 /* 1436 * Hashed negative dentry with O_DIRECTORY: dentry was 1437 * revalidated and is fine, no need to perform lookup 1438 * again 1439 */ 1440 return -ENOENT; 1441 } 1442 goto no_open; 1443 } 1444 1445 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 1446 return -ENAMETOOLONG; 1447 1448 if (open_flags & O_CREAT) { 1449 attr.ia_valid |= ATTR_MODE; 1450 attr.ia_mode = mode & ~current_umask(); 1451 } 1452 if (open_flags & O_TRUNC) { 1453 attr.ia_valid |= ATTR_SIZE; 1454 attr.ia_size = 0; 1455 } 1456 1457 ctx = create_nfs_open_context(dentry, open_flags); 1458 err = PTR_ERR(ctx); 1459 if (IS_ERR(ctx)) 1460 goto out; 1461 1462 nfs_block_sillyrename(dentry->d_parent); 1463 inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr); 1464 d_drop(dentry); 1465 if (IS_ERR(inode)) { 1466 nfs_unblock_sillyrename(dentry->d_parent); 1467 put_nfs_open_context(ctx); 1468 err = PTR_ERR(inode); 1469 switch (err) { 1470 case -ENOENT: 1471 d_add(dentry, NULL); 1472 break; 1473 case -EISDIR: 1474 case -ENOTDIR: 1475 goto no_open; 1476 case -ELOOP: 1477 if (!(open_flags & O_NOFOLLOW)) 1478 goto no_open; 1479 break; 1480 /* case -EINVAL: */ 1481 default: 1482 break; 1483 } 1484 goto out; 1485 } 1486 res = d_add_unique(dentry, inode); 1487 if (res != NULL) 1488 dentry = res; 1489 1490 nfs_unblock_sillyrename(dentry->d_parent); 1491 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1492 1493 err = nfs_finish_open(ctx, dentry, file, open_flags, opened); 1494 1495 dput(res); 1496 out: 1497 return err; 1498 1499 no_open: 1500 res = nfs_lookup(dir, dentry, NULL); 1501 err = PTR_ERR(res); 1502 if (IS_ERR(res)) 1503 goto out; 1504 1505 return finish_no_open(file, res); 1506 } 1507 1508 static int nfs4_lookup_revalidate(struct dentry *dentry, struct nameidata *nd) 1509 { 1510 struct dentry *parent = NULL; 1511 struct inode *inode; 1512 struct inode *dir; 1513 int ret = 0; 1514 1515 if (nd->flags & LOOKUP_RCU) 1516 return -ECHILD; 1517 1518 if (!(nd->flags & LOOKUP_OPEN) || (nd->flags & LOOKUP_DIRECTORY)) 1519 goto no_open; 1520 if (d_mountpoint(dentry)) 1521 goto no_open; 1522 1523 inode = dentry->d_inode; 1524 parent = dget_parent(dentry); 1525 dir = parent->d_inode; 1526 1527 /* We can't create new files in nfs_open_revalidate(), so we 1528 * optimize away revalidation of negative dentries. 1529 */ 1530 if (inode == NULL) { 1531 if (!nfs_neg_need_reval(dir, dentry, nd)) 1532 ret = 1; 1533 goto out; 1534 } 1535 1536 /* NFS only supports OPEN on regular files */ 1537 if (!S_ISREG(inode->i_mode)) 1538 goto no_open_dput; 1539 /* We cannot do exclusive creation on a positive dentry */ 1540 if (nd && nd->flags & LOOKUP_EXCL) 1541 goto no_open_dput; 1542 1543 /* Let f_op->open() actually open (and revalidate) the file */ 1544 ret = 1; 1545 1546 out: 1547 dput(parent); 1548 return ret; 1549 1550 no_open_dput: 1551 dput(parent); 1552 no_open: 1553 return nfs_lookup_revalidate(dentry, nd); 1554 } 1555 1556 #endif /* CONFIG_NFSV4 */ 1557 1558 /* 1559 * Code common to create, mkdir, and mknod. 1560 */ 1561 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, 1562 struct nfs_fattr *fattr) 1563 { 1564 struct dentry *parent = dget_parent(dentry); 1565 struct inode *dir = parent->d_inode; 1566 struct inode *inode; 1567 int error = -EACCES; 1568 1569 d_drop(dentry); 1570 1571 /* We may have been initialized further down */ 1572 if (dentry->d_inode) 1573 goto out; 1574 if (fhandle->size == 0) { 1575 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); 1576 if (error) 1577 goto out_error; 1578 } 1579 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1580 if (!(fattr->valid & NFS_ATTR_FATTR)) { 1581 struct nfs_server *server = NFS_SB(dentry->d_sb); 1582 error = server->nfs_client->rpc_ops->getattr(server, fhandle, fattr); 1583 if (error < 0) 1584 goto out_error; 1585 } 1586 inode = nfs_fhget(dentry->d_sb, fhandle, fattr); 1587 error = PTR_ERR(inode); 1588 if (IS_ERR(inode)) 1589 goto out_error; 1590 d_add(dentry, inode); 1591 out: 1592 dput(parent); 1593 return 0; 1594 out_error: 1595 nfs_mark_for_revalidate(dir); 1596 dput(parent); 1597 return error; 1598 } 1599 1600 /* 1601 * Following a failed create operation, we drop the dentry rather 1602 * than retain a negative dentry. This avoids a problem in the event 1603 * that the operation succeeded on the server, but an error in the 1604 * reply path made it appear to have failed. 1605 */ 1606 static int nfs_create(struct inode *dir, struct dentry *dentry, 1607 umode_t mode, struct nameidata *nd) 1608 { 1609 struct iattr attr; 1610 int error; 1611 int open_flags = O_CREAT|O_EXCL; 1612 1613 dfprintk(VFS, "NFS: create(%s/%ld), %s\n", 1614 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1615 1616 attr.ia_mode = mode; 1617 attr.ia_valid = ATTR_MODE; 1618 1619 if (nd && !(nd->flags & LOOKUP_EXCL)) 1620 open_flags = O_CREAT; 1621 1622 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags); 1623 if (error != 0) 1624 goto out_err; 1625 return 0; 1626 out_err: 1627 d_drop(dentry); 1628 return error; 1629 } 1630 1631 /* 1632 * See comments for nfs_proc_create regarding failed operations. 1633 */ 1634 static int 1635 nfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev) 1636 { 1637 struct iattr attr; 1638 int status; 1639 1640 dfprintk(VFS, "NFS: mknod(%s/%ld), %s\n", 1641 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1642 1643 if (!new_valid_dev(rdev)) 1644 return -EINVAL; 1645 1646 attr.ia_mode = mode; 1647 attr.ia_valid = ATTR_MODE; 1648 1649 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); 1650 if (status != 0) 1651 goto out_err; 1652 return 0; 1653 out_err: 1654 d_drop(dentry); 1655 return status; 1656 } 1657 1658 /* 1659 * See comments for nfs_proc_create regarding failed operations. 1660 */ 1661 static int nfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 1662 { 1663 struct iattr attr; 1664 int error; 1665 1666 dfprintk(VFS, "NFS: mkdir(%s/%ld), %s\n", 1667 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1668 1669 attr.ia_valid = ATTR_MODE; 1670 attr.ia_mode = mode | S_IFDIR; 1671 1672 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); 1673 if (error != 0) 1674 goto out_err; 1675 return 0; 1676 out_err: 1677 d_drop(dentry); 1678 return error; 1679 } 1680 1681 static void nfs_dentry_handle_enoent(struct dentry *dentry) 1682 { 1683 if (dentry->d_inode != NULL && !d_unhashed(dentry)) 1684 d_delete(dentry); 1685 } 1686 1687 static int nfs_rmdir(struct inode *dir, struct dentry *dentry) 1688 { 1689 int error; 1690 1691 dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n", 1692 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1693 1694 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 1695 /* Ensure the VFS deletes this inode */ 1696 if (error == 0 && dentry->d_inode != NULL) 1697 clear_nlink(dentry->d_inode); 1698 else if (error == -ENOENT) 1699 nfs_dentry_handle_enoent(dentry); 1700 1701 return error; 1702 } 1703 1704 /* 1705 * Remove a file after making sure there are no pending writes, 1706 * and after checking that the file has only one user. 1707 * 1708 * We invalidate the attribute cache and free the inode prior to the operation 1709 * to avoid possible races if the server reuses the inode. 1710 */ 1711 static int nfs_safe_remove(struct dentry *dentry) 1712 { 1713 struct inode *dir = dentry->d_parent->d_inode; 1714 struct inode *inode = dentry->d_inode; 1715 int error = -EBUSY; 1716 1717 dfprintk(VFS, "NFS: safe_remove(%s/%s)\n", 1718 dentry->d_parent->d_name.name, dentry->d_name.name); 1719 1720 /* If the dentry was sillyrenamed, we simply call d_delete() */ 1721 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1722 error = 0; 1723 goto out; 1724 } 1725 1726 if (inode != NULL) { 1727 nfs_inode_return_delegation(inode); 1728 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1729 /* The VFS may want to delete this inode */ 1730 if (error == 0) 1731 nfs_drop_nlink(inode); 1732 nfs_mark_for_revalidate(inode); 1733 } else 1734 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1735 if (error == -ENOENT) 1736 nfs_dentry_handle_enoent(dentry); 1737 out: 1738 return error; 1739 } 1740 1741 /* We do silly rename. In case sillyrename() returns -EBUSY, the inode 1742 * belongs to an active ".nfs..." file and we return -EBUSY. 1743 * 1744 * If sillyrename() returns 0, we do nothing, otherwise we unlink. 1745 */ 1746 static int nfs_unlink(struct inode *dir, struct dentry *dentry) 1747 { 1748 int error; 1749 int need_rehash = 0; 1750 1751 dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id, 1752 dir->i_ino, dentry->d_name.name); 1753 1754 spin_lock(&dentry->d_lock); 1755 if (dentry->d_count > 1) { 1756 spin_unlock(&dentry->d_lock); 1757 /* Start asynchronous writeout of the inode */ 1758 write_inode_now(dentry->d_inode, 0); 1759 error = nfs_sillyrename(dir, dentry); 1760 return error; 1761 } 1762 if (!d_unhashed(dentry)) { 1763 __d_drop(dentry); 1764 need_rehash = 1; 1765 } 1766 spin_unlock(&dentry->d_lock); 1767 error = nfs_safe_remove(dentry); 1768 if (!error || error == -ENOENT) { 1769 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1770 } else if (need_rehash) 1771 d_rehash(dentry); 1772 return error; 1773 } 1774 1775 /* 1776 * To create a symbolic link, most file systems instantiate a new inode, 1777 * add a page to it containing the path, then write it out to the disk 1778 * using prepare_write/commit_write. 1779 * 1780 * Unfortunately the NFS client can't create the in-core inode first 1781 * because it needs a file handle to create an in-core inode (see 1782 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the 1783 * symlink request has completed on the server. 1784 * 1785 * So instead we allocate a raw page, copy the symname into it, then do 1786 * the SYMLINK request with the page as the buffer. If it succeeds, we 1787 * now have a new file handle and can instantiate an in-core NFS inode 1788 * and move the raw page into its mapping. 1789 */ 1790 static int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) 1791 { 1792 struct pagevec lru_pvec; 1793 struct page *page; 1794 char *kaddr; 1795 struct iattr attr; 1796 unsigned int pathlen = strlen(symname); 1797 int error; 1798 1799 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id, 1800 dir->i_ino, dentry->d_name.name, symname); 1801 1802 if (pathlen > PAGE_SIZE) 1803 return -ENAMETOOLONG; 1804 1805 attr.ia_mode = S_IFLNK | S_IRWXUGO; 1806 attr.ia_valid = ATTR_MODE; 1807 1808 page = alloc_page(GFP_HIGHUSER); 1809 if (!page) 1810 return -ENOMEM; 1811 1812 kaddr = kmap_atomic(page); 1813 memcpy(kaddr, symname, pathlen); 1814 if (pathlen < PAGE_SIZE) 1815 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); 1816 kunmap_atomic(kaddr); 1817 1818 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr); 1819 if (error != 0) { 1820 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s) error %d\n", 1821 dir->i_sb->s_id, dir->i_ino, 1822 dentry->d_name.name, symname, error); 1823 d_drop(dentry); 1824 __free_page(page); 1825 return error; 1826 } 1827 1828 /* 1829 * No big deal if we can't add this page to the page cache here. 1830 * READLINK will get the missing page from the server if needed. 1831 */ 1832 pagevec_init(&lru_pvec, 0); 1833 if (!add_to_page_cache(page, dentry->d_inode->i_mapping, 0, 1834 GFP_KERNEL)) { 1835 pagevec_add(&lru_pvec, page); 1836 pagevec_lru_add_file(&lru_pvec); 1837 SetPageUptodate(page); 1838 unlock_page(page); 1839 } else 1840 __free_page(page); 1841 1842 return 0; 1843 } 1844 1845 static int 1846 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 1847 { 1848 struct inode *inode = old_dentry->d_inode; 1849 int error; 1850 1851 dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n", 1852 old_dentry->d_parent->d_name.name, old_dentry->d_name.name, 1853 dentry->d_parent->d_name.name, dentry->d_name.name); 1854 1855 nfs_inode_return_delegation(inode); 1856 1857 d_drop(dentry); 1858 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 1859 if (error == 0) { 1860 ihold(inode); 1861 d_add(dentry, inode); 1862 } 1863 return error; 1864 } 1865 1866 /* 1867 * RENAME 1868 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a 1869 * different file handle for the same inode after a rename (e.g. when 1870 * moving to a different directory). A fail-safe method to do so would 1871 * be to look up old_dir/old_name, create a link to new_dir/new_name and 1872 * rename the old file using the sillyrename stuff. This way, the original 1873 * file in old_dir will go away when the last process iput()s the inode. 1874 * 1875 * FIXED. 1876 * 1877 * It actually works quite well. One needs to have the possibility for 1878 * at least one ".nfs..." file in each directory the file ever gets 1879 * moved or linked to which happens automagically with the new 1880 * implementation that only depends on the dcache stuff instead of 1881 * using the inode layer 1882 * 1883 * Unfortunately, things are a little more complicated than indicated 1884 * above. For a cross-directory move, we want to make sure we can get 1885 * rid of the old inode after the operation. This means there must be 1886 * no pending writes (if it's a file), and the use count must be 1. 1887 * If these conditions are met, we can drop the dentries before doing 1888 * the rename. 1889 */ 1890 static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, 1891 struct inode *new_dir, struct dentry *new_dentry) 1892 { 1893 struct inode *old_inode = old_dentry->d_inode; 1894 struct inode *new_inode = new_dentry->d_inode; 1895 struct dentry *dentry = NULL, *rehash = NULL; 1896 int error = -EBUSY; 1897 1898 dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n", 1899 old_dentry->d_parent->d_name.name, old_dentry->d_name.name, 1900 new_dentry->d_parent->d_name.name, new_dentry->d_name.name, 1901 new_dentry->d_count); 1902 1903 /* 1904 * For non-directories, check whether the target is busy and if so, 1905 * make a copy of the dentry and then do a silly-rename. If the 1906 * silly-rename succeeds, the copied dentry is hashed and becomes 1907 * the new target. 1908 */ 1909 if (new_inode && !S_ISDIR(new_inode->i_mode)) { 1910 /* 1911 * To prevent any new references to the target during the 1912 * rename, we unhash the dentry in advance. 1913 */ 1914 if (!d_unhashed(new_dentry)) { 1915 d_drop(new_dentry); 1916 rehash = new_dentry; 1917 } 1918 1919 if (new_dentry->d_count > 2) { 1920 int err; 1921 1922 /* copy the target dentry's name */ 1923 dentry = d_alloc(new_dentry->d_parent, 1924 &new_dentry->d_name); 1925 if (!dentry) 1926 goto out; 1927 1928 /* silly-rename the existing target ... */ 1929 err = nfs_sillyrename(new_dir, new_dentry); 1930 if (err) 1931 goto out; 1932 1933 new_dentry = dentry; 1934 rehash = NULL; 1935 new_inode = NULL; 1936 } 1937 } 1938 1939 nfs_inode_return_delegation(old_inode); 1940 if (new_inode != NULL) 1941 nfs_inode_return_delegation(new_inode); 1942 1943 error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name, 1944 new_dir, &new_dentry->d_name); 1945 nfs_mark_for_revalidate(old_inode); 1946 out: 1947 if (rehash) 1948 d_rehash(rehash); 1949 if (!error) { 1950 if (new_inode != NULL) 1951 nfs_drop_nlink(new_inode); 1952 d_move(old_dentry, new_dentry); 1953 nfs_set_verifier(new_dentry, 1954 nfs_save_change_attribute(new_dir)); 1955 } else if (error == -ENOENT) 1956 nfs_dentry_handle_enoent(old_dentry); 1957 1958 /* new dentry created? */ 1959 if (dentry) 1960 dput(dentry); 1961 return error; 1962 } 1963 1964 static DEFINE_SPINLOCK(nfs_access_lru_lock); 1965 static LIST_HEAD(nfs_access_lru_list); 1966 static atomic_long_t nfs_access_nr_entries; 1967 1968 static void nfs_access_free_entry(struct nfs_access_entry *entry) 1969 { 1970 put_rpccred(entry->cred); 1971 kfree(entry); 1972 smp_mb__before_atomic_dec(); 1973 atomic_long_dec(&nfs_access_nr_entries); 1974 smp_mb__after_atomic_dec(); 1975 } 1976 1977 static void nfs_access_free_list(struct list_head *head) 1978 { 1979 struct nfs_access_entry *cache; 1980 1981 while (!list_empty(head)) { 1982 cache = list_entry(head->next, struct nfs_access_entry, lru); 1983 list_del(&cache->lru); 1984 nfs_access_free_entry(cache); 1985 } 1986 } 1987 1988 int nfs_access_cache_shrinker(struct shrinker *shrink, 1989 struct shrink_control *sc) 1990 { 1991 LIST_HEAD(head); 1992 struct nfs_inode *nfsi, *next; 1993 struct nfs_access_entry *cache; 1994 int nr_to_scan = sc->nr_to_scan; 1995 gfp_t gfp_mask = sc->gfp_mask; 1996 1997 if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL) 1998 return (nr_to_scan == 0) ? 0 : -1; 1999 2000 spin_lock(&nfs_access_lru_lock); 2001 list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) { 2002 struct inode *inode; 2003 2004 if (nr_to_scan-- == 0) 2005 break; 2006 inode = &nfsi->vfs_inode; 2007 spin_lock(&inode->i_lock); 2008 if (list_empty(&nfsi->access_cache_entry_lru)) 2009 goto remove_lru_entry; 2010 cache = list_entry(nfsi->access_cache_entry_lru.next, 2011 struct nfs_access_entry, lru); 2012 list_move(&cache->lru, &head); 2013 rb_erase(&cache->rb_node, &nfsi->access_cache); 2014 if (!list_empty(&nfsi->access_cache_entry_lru)) 2015 list_move_tail(&nfsi->access_cache_inode_lru, 2016 &nfs_access_lru_list); 2017 else { 2018 remove_lru_entry: 2019 list_del_init(&nfsi->access_cache_inode_lru); 2020 smp_mb__before_clear_bit(); 2021 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); 2022 smp_mb__after_clear_bit(); 2023 } 2024 spin_unlock(&inode->i_lock); 2025 } 2026 spin_unlock(&nfs_access_lru_lock); 2027 nfs_access_free_list(&head); 2028 return (atomic_long_read(&nfs_access_nr_entries) / 100) * sysctl_vfs_cache_pressure; 2029 } 2030 2031 static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head) 2032 { 2033 struct rb_root *root_node = &nfsi->access_cache; 2034 struct rb_node *n; 2035 struct nfs_access_entry *entry; 2036 2037 /* Unhook entries from the cache */ 2038 while ((n = rb_first(root_node)) != NULL) { 2039 entry = rb_entry(n, struct nfs_access_entry, rb_node); 2040 rb_erase(n, root_node); 2041 list_move(&entry->lru, head); 2042 } 2043 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; 2044 } 2045 2046 void nfs_access_zap_cache(struct inode *inode) 2047 { 2048 LIST_HEAD(head); 2049 2050 if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0) 2051 return; 2052 /* Remove from global LRU init */ 2053 spin_lock(&nfs_access_lru_lock); 2054 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2055 list_del_init(&NFS_I(inode)->access_cache_inode_lru); 2056 2057 spin_lock(&inode->i_lock); 2058 __nfs_access_zap_cache(NFS_I(inode), &head); 2059 spin_unlock(&inode->i_lock); 2060 spin_unlock(&nfs_access_lru_lock); 2061 nfs_access_free_list(&head); 2062 } 2063 2064 static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred) 2065 { 2066 struct rb_node *n = NFS_I(inode)->access_cache.rb_node; 2067 struct nfs_access_entry *entry; 2068 2069 while (n != NULL) { 2070 entry = rb_entry(n, struct nfs_access_entry, rb_node); 2071 2072 if (cred < entry->cred) 2073 n = n->rb_left; 2074 else if (cred > entry->cred) 2075 n = n->rb_right; 2076 else 2077 return entry; 2078 } 2079 return NULL; 2080 } 2081 2082 static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) 2083 { 2084 struct nfs_inode *nfsi = NFS_I(inode); 2085 struct nfs_access_entry *cache; 2086 int err = -ENOENT; 2087 2088 spin_lock(&inode->i_lock); 2089 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2090 goto out_zap; 2091 cache = nfs_access_search_rbtree(inode, cred); 2092 if (cache == NULL) 2093 goto out; 2094 if (!nfs_have_delegated_attributes(inode) && 2095 !time_in_range_open(jiffies, cache->jiffies, cache->jiffies + nfsi->attrtimeo)) 2096 goto out_stale; 2097 res->jiffies = cache->jiffies; 2098 res->cred = cache->cred; 2099 res->mask = cache->mask; 2100 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru); 2101 err = 0; 2102 out: 2103 spin_unlock(&inode->i_lock); 2104 return err; 2105 out_stale: 2106 rb_erase(&cache->rb_node, &nfsi->access_cache); 2107 list_del(&cache->lru); 2108 spin_unlock(&inode->i_lock); 2109 nfs_access_free_entry(cache); 2110 return -ENOENT; 2111 out_zap: 2112 spin_unlock(&inode->i_lock); 2113 nfs_access_zap_cache(inode); 2114 return -ENOENT; 2115 } 2116 2117 static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) 2118 { 2119 struct nfs_inode *nfsi = NFS_I(inode); 2120 struct rb_root *root_node = &nfsi->access_cache; 2121 struct rb_node **p = &root_node->rb_node; 2122 struct rb_node *parent = NULL; 2123 struct nfs_access_entry *entry; 2124 2125 spin_lock(&inode->i_lock); 2126 while (*p != NULL) { 2127 parent = *p; 2128 entry = rb_entry(parent, struct nfs_access_entry, rb_node); 2129 2130 if (set->cred < entry->cred) 2131 p = &parent->rb_left; 2132 else if (set->cred > entry->cred) 2133 p = &parent->rb_right; 2134 else 2135 goto found; 2136 } 2137 rb_link_node(&set->rb_node, parent, p); 2138 rb_insert_color(&set->rb_node, root_node); 2139 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 2140 spin_unlock(&inode->i_lock); 2141 return; 2142 found: 2143 rb_replace_node(parent, &set->rb_node, root_node); 2144 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 2145 list_del(&entry->lru); 2146 spin_unlock(&inode->i_lock); 2147 nfs_access_free_entry(entry); 2148 } 2149 2150 static void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) 2151 { 2152 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); 2153 if (cache == NULL) 2154 return; 2155 RB_CLEAR_NODE(&cache->rb_node); 2156 cache->jiffies = set->jiffies; 2157 cache->cred = get_rpccred(set->cred); 2158 cache->mask = set->mask; 2159 2160 nfs_access_add_rbtree(inode, cache); 2161 2162 /* Update accounting */ 2163 smp_mb__before_atomic_inc(); 2164 atomic_long_inc(&nfs_access_nr_entries); 2165 smp_mb__after_atomic_inc(); 2166 2167 /* Add inode to global LRU list */ 2168 if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) { 2169 spin_lock(&nfs_access_lru_lock); 2170 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2171 list_add_tail(&NFS_I(inode)->access_cache_inode_lru, 2172 &nfs_access_lru_list); 2173 spin_unlock(&nfs_access_lru_lock); 2174 } 2175 } 2176 2177 static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) 2178 { 2179 struct nfs_access_entry cache; 2180 int status; 2181 2182 status = nfs_access_get_cached(inode, cred, &cache); 2183 if (status == 0) 2184 goto out; 2185 2186 /* Be clever: ask server to check for all possible rights */ 2187 cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ; 2188 cache.cred = cred; 2189 cache.jiffies = jiffies; 2190 status = NFS_PROTO(inode)->access(inode, &cache); 2191 if (status != 0) { 2192 if (status == -ESTALE) { 2193 nfs_zap_caches(inode); 2194 if (!S_ISDIR(inode->i_mode)) 2195 set_bit(NFS_INO_STALE, &NFS_I(inode)->flags); 2196 } 2197 return status; 2198 } 2199 nfs_access_add_cache(inode, &cache); 2200 out: 2201 if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) 2202 return 0; 2203 return -EACCES; 2204 } 2205 2206 static int nfs_open_permission_mask(int openflags) 2207 { 2208 int mask = 0; 2209 2210 if ((openflags & O_ACCMODE) != O_WRONLY) 2211 mask |= MAY_READ; 2212 if ((openflags & O_ACCMODE) != O_RDONLY) 2213 mask |= MAY_WRITE; 2214 if (openflags & __FMODE_EXEC) 2215 mask |= MAY_EXEC; 2216 return mask; 2217 } 2218 2219 int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags) 2220 { 2221 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); 2222 } 2223 2224 int nfs_permission(struct inode *inode, int mask) 2225 { 2226 struct rpc_cred *cred; 2227 int res = 0; 2228 2229 if (mask & MAY_NOT_BLOCK) 2230 return -ECHILD; 2231 2232 nfs_inc_stats(inode, NFSIOS_VFSACCESS); 2233 2234 if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) 2235 goto out; 2236 /* Is this sys_access() ? */ 2237 if (mask & (MAY_ACCESS | MAY_CHDIR)) 2238 goto force_lookup; 2239 2240 switch (inode->i_mode & S_IFMT) { 2241 case S_IFLNK: 2242 goto out; 2243 case S_IFREG: 2244 /* NFSv4 has atomic_open... */ 2245 if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN) 2246 && (mask & MAY_OPEN) 2247 && !(mask & MAY_EXEC)) 2248 goto out; 2249 break; 2250 case S_IFDIR: 2251 /* 2252 * Optimize away all write operations, since the server 2253 * will check permissions when we perform the op. 2254 */ 2255 if ((mask & MAY_WRITE) && !(mask & MAY_READ)) 2256 goto out; 2257 } 2258 2259 force_lookup: 2260 if (!NFS_PROTO(inode)->access) 2261 goto out_notsup; 2262 2263 cred = rpc_lookup_cred(); 2264 if (!IS_ERR(cred)) { 2265 res = nfs_do_access(inode, cred, mask); 2266 put_rpccred(cred); 2267 } else 2268 res = PTR_ERR(cred); 2269 out: 2270 if (!res && (mask & MAY_EXEC) && !execute_ok(inode)) 2271 res = -EACCES; 2272 2273 dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n", 2274 inode->i_sb->s_id, inode->i_ino, mask, res); 2275 return res; 2276 out_notsup: 2277 res = nfs_revalidate_inode(NFS_SERVER(inode), inode); 2278 if (res == 0) 2279 res = generic_permission(inode, mask); 2280 goto out; 2281 } 2282 2283 /* 2284 * Local variables: 2285 * version-control: t 2286 * kept-new-versions: 5 2287 * End: 2288 */ 2289