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_shared = 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 atomic_t refcount; 149 int size; 150 int eof_index; 151 u64 last_cookie; 152 struct nfs_cache_array_entry array[0]; 153 }; 154 155 typedef int (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, int); 156 typedef struct { 157 struct file *file; 158 struct page *page; 159 struct dir_context *ctx; 160 unsigned long page_index; 161 u64 *dir_cookie; 162 u64 last_cookie; 163 loff_t current_index; 164 decode_dirent_t decode; 165 166 unsigned long timestamp; 167 unsigned long gencount; 168 unsigned int cache_entry_index; 169 unsigned int plus:1; 170 unsigned int eof:1; 171 } nfs_readdir_descriptor_t; 172 173 /* 174 * The caller is responsible for calling nfs_readdir_release_array(page) 175 */ 176 static 177 struct nfs_cache_array *nfs_readdir_get_array(struct page *page) 178 { 179 void *ptr; 180 if (page == NULL) 181 return ERR_PTR(-EIO); 182 ptr = kmap(page); 183 if (ptr == NULL) 184 return ERR_PTR(-ENOMEM); 185 return ptr; 186 } 187 188 static 189 void nfs_readdir_release_array(struct page *page) 190 { 191 kunmap(page); 192 } 193 194 /* 195 * we are freeing strings created by nfs_add_to_readdir_array() 196 */ 197 static 198 void nfs_readdir_clear_array(struct page *page) 199 { 200 struct nfs_cache_array *array; 201 int i; 202 203 array = kmap_atomic(page); 204 if (atomic_dec_and_test(&array->refcount)) 205 for (i = 0; i < array->size; i++) 206 kfree(array->array[i].string.name); 207 kunmap_atomic(array); 208 } 209 210 static bool grab_page(struct page *page) 211 { 212 struct nfs_cache_array *array = kmap_atomic(page); 213 bool res = atomic_inc_not_zero(&array->refcount); 214 kunmap_atomic(array); 215 return res; 216 } 217 218 /* 219 * the caller is responsible for freeing qstr.name 220 * when called by nfs_readdir_add_to_array, the strings will be freed in 221 * nfs_clear_readdir_array() 222 */ 223 static 224 int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int len) 225 { 226 string->len = len; 227 string->name = kmemdup(name, len, GFP_KERNEL); 228 if (string->name == NULL) 229 return -ENOMEM; 230 /* 231 * Avoid a kmemleak false positive. The pointer to the name is stored 232 * in a page cache page which kmemleak does not scan. 233 */ 234 kmemleak_not_leak(string->name); 235 string->hash = full_name_hash(NULL, name, len); 236 return 0; 237 } 238 239 static 240 int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page) 241 { 242 struct nfs_cache_array *array = nfs_readdir_get_array(page); 243 struct nfs_cache_array_entry *cache_entry; 244 int ret; 245 246 if (IS_ERR(array)) 247 return PTR_ERR(array); 248 249 cache_entry = &array->array[array->size]; 250 251 /* Check that this entry lies within the page bounds */ 252 ret = -ENOSPC; 253 if ((char *)&cache_entry[1] - (char *)page_address(page) > PAGE_SIZE) 254 goto out; 255 256 cache_entry->cookie = entry->prev_cookie; 257 cache_entry->ino = entry->ino; 258 cache_entry->d_type = entry->d_type; 259 ret = nfs_readdir_make_qstr(&cache_entry->string, entry->name, entry->len); 260 if (ret) 261 goto out; 262 array->last_cookie = entry->cookie; 263 array->size++; 264 if (entry->eof != 0) 265 array->eof_index = array->size; 266 out: 267 nfs_readdir_release_array(page); 268 return ret; 269 } 270 271 static 272 int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc) 273 { 274 loff_t diff = desc->ctx->pos - desc->current_index; 275 unsigned int index; 276 277 if (diff < 0) 278 goto out_eof; 279 if (diff >= array->size) { 280 if (array->eof_index >= 0) 281 goto out_eof; 282 return -EAGAIN; 283 } 284 285 index = (unsigned int)diff; 286 *desc->dir_cookie = array->array[index].cookie; 287 desc->cache_entry_index = index; 288 return 0; 289 out_eof: 290 desc->eof = 1; 291 return -EBADCOOKIE; 292 } 293 294 static bool 295 nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi) 296 { 297 if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA)) 298 return false; 299 smp_rmb(); 300 return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags); 301 } 302 303 static 304 int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc) 305 { 306 int i; 307 loff_t new_pos; 308 int status = -EAGAIN; 309 310 for (i = 0; i < array->size; i++) { 311 if (array->array[i].cookie == *desc->dir_cookie) { 312 struct nfs_inode *nfsi = NFS_I(file_inode(desc->file)); 313 struct nfs_open_dir_context *ctx = desc->file->private_data; 314 315 new_pos = desc->current_index + i; 316 if (ctx->attr_gencount != nfsi->attr_gencount || 317 !nfs_readdir_inode_mapping_valid(nfsi)) { 318 ctx->duped = 0; 319 ctx->attr_gencount = nfsi->attr_gencount; 320 } else if (new_pos < desc->ctx->pos) { 321 if (ctx->duped > 0 322 && ctx->dup_cookie == *desc->dir_cookie) { 323 if (printk_ratelimit()) { 324 pr_notice("NFS: directory %pD2 contains a readdir loop." 325 "Please contact your server vendor. " 326 "The file: %.*s has duplicate cookie %llu\n", 327 desc->file, array->array[i].string.len, 328 array->array[i].string.name, *desc->dir_cookie); 329 } 330 status = -ELOOP; 331 goto out; 332 } 333 ctx->dup_cookie = *desc->dir_cookie; 334 ctx->duped = -1; 335 } 336 desc->ctx->pos = new_pos; 337 desc->cache_entry_index = i; 338 return 0; 339 } 340 } 341 if (array->eof_index >= 0) { 342 status = -EBADCOOKIE; 343 if (*desc->dir_cookie == array->last_cookie) 344 desc->eof = 1; 345 } 346 out: 347 return status; 348 } 349 350 static 351 int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc) 352 { 353 struct nfs_cache_array *array; 354 int status; 355 356 array = nfs_readdir_get_array(desc->page); 357 if (IS_ERR(array)) { 358 status = PTR_ERR(array); 359 goto out; 360 } 361 362 if (*desc->dir_cookie == 0) 363 status = nfs_readdir_search_for_pos(array, desc); 364 else 365 status = nfs_readdir_search_for_cookie(array, desc); 366 367 if (status == -EAGAIN) { 368 desc->last_cookie = array->last_cookie; 369 desc->current_index += array->size; 370 desc->page_index++; 371 } 372 nfs_readdir_release_array(desc->page); 373 out: 374 return status; 375 } 376 377 /* Fill a page with xdr information before transferring to the cache page */ 378 static 379 int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc, 380 struct nfs_entry *entry, struct file *file, struct inode *inode) 381 { 382 struct nfs_open_dir_context *ctx = file->private_data; 383 struct rpc_cred *cred = ctx->cred; 384 unsigned long timestamp, gencount; 385 int error; 386 387 again: 388 timestamp = jiffies; 389 gencount = nfs_inc_attr_generation_counter(); 390 error = NFS_PROTO(inode)->readdir(file_dentry(file), cred, entry->cookie, pages, 391 NFS_SERVER(inode)->dtsize, desc->plus); 392 if (error < 0) { 393 /* We requested READDIRPLUS, but the server doesn't grok it */ 394 if (error == -ENOTSUPP && desc->plus) { 395 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; 396 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 397 desc->plus = 0; 398 goto again; 399 } 400 goto error; 401 } 402 desc->timestamp = timestamp; 403 desc->gencount = gencount; 404 error: 405 return error; 406 } 407 408 static int xdr_decode(nfs_readdir_descriptor_t *desc, 409 struct nfs_entry *entry, struct xdr_stream *xdr) 410 { 411 int error; 412 413 error = desc->decode(xdr, entry, desc->plus); 414 if (error) 415 return error; 416 entry->fattr->time_start = desc->timestamp; 417 entry->fattr->gencount = desc->gencount; 418 return 0; 419 } 420 421 /* Match file and dirent using either filehandle or fileid 422 * Note: caller is responsible for checking the fsid 423 */ 424 static 425 int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) 426 { 427 struct inode *inode; 428 struct nfs_inode *nfsi; 429 430 if (d_really_is_negative(dentry)) 431 return 0; 432 433 inode = d_inode(dentry); 434 if (is_bad_inode(inode) || NFS_STALE(inode)) 435 return 0; 436 437 nfsi = NFS_I(inode); 438 if (entry->fattr->fileid != nfsi->fileid) 439 return 0; 440 if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0) 441 return 0; 442 return 1; 443 } 444 445 static 446 bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx) 447 { 448 if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS)) 449 return false; 450 if (test_and_clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(dir)->flags)) 451 return true; 452 if (ctx->pos == 0) 453 return true; 454 return false; 455 } 456 457 /* 458 * This function is called by the lookup and getattr code to request the 459 * use of readdirplus to accelerate any future lookups in the same 460 * directory. 461 */ 462 void nfs_advise_use_readdirplus(struct inode *dir) 463 { 464 struct nfs_inode *nfsi = NFS_I(dir); 465 466 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && 467 !list_empty(&nfsi->open_files)) 468 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); 469 } 470 471 /* 472 * This function is mainly for use by nfs_getattr(). 473 * 474 * If this is an 'ls -l', we want to force use of readdirplus. 475 * Do this by checking if there is an active file descriptor 476 * and calling nfs_advise_use_readdirplus, then forcing a 477 * cache flush. 478 */ 479 void nfs_force_use_readdirplus(struct inode *dir) 480 { 481 struct nfs_inode *nfsi = NFS_I(dir); 482 483 if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && 484 !list_empty(&nfsi->open_files)) { 485 set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); 486 invalidate_mapping_pages(dir->i_mapping, 0, -1); 487 } 488 } 489 490 static 491 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry) 492 { 493 struct qstr filename = QSTR_INIT(entry->name, entry->len); 494 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 495 struct dentry *dentry; 496 struct dentry *alias; 497 struct inode *dir = d_inode(parent); 498 struct inode *inode; 499 int status; 500 501 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID)) 502 return; 503 if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID)) 504 return; 505 if (filename.len == 0) 506 return; 507 /* Validate that the name doesn't contain any illegal '\0' */ 508 if (strnlen(filename.name, filename.len) != filename.len) 509 return; 510 /* ...or '/' */ 511 if (strnchr(filename.name, filename.len, '/')) 512 return; 513 if (filename.name[0] == '.') { 514 if (filename.len == 1) 515 return; 516 if (filename.len == 2 && filename.name[1] == '.') 517 return; 518 } 519 filename.hash = full_name_hash(parent, filename.name, filename.len); 520 521 dentry = d_lookup(parent, &filename); 522 again: 523 if (!dentry) { 524 dentry = d_alloc_parallel(parent, &filename, &wq); 525 if (IS_ERR(dentry)) 526 return; 527 } 528 if (!d_in_lookup(dentry)) { 529 /* Is there a mountpoint here? If so, just exit */ 530 if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid, 531 &entry->fattr->fsid)) 532 goto out; 533 if (nfs_same_file(dentry, entry)) { 534 if (!entry->fh->size) 535 goto out; 536 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 537 status = nfs_refresh_inode(d_inode(dentry), entry->fattr); 538 if (!status) 539 nfs_setsecurity(d_inode(dentry), entry->fattr, entry->label); 540 goto out; 541 } else { 542 d_invalidate(dentry); 543 dput(dentry); 544 dentry = NULL; 545 goto again; 546 } 547 } 548 if (!entry->fh->size) { 549 d_lookup_done(dentry); 550 goto out; 551 } 552 553 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label); 554 alias = d_splice_alias(inode, dentry); 555 d_lookup_done(dentry); 556 if (alias) { 557 if (IS_ERR(alias)) 558 goto out; 559 dput(dentry); 560 dentry = alias; 561 } 562 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 563 out: 564 dput(dentry); 565 } 566 567 /* Perform conversion from xdr to cache array */ 568 static 569 int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, 570 struct page **xdr_pages, struct page *page, unsigned int buflen) 571 { 572 struct xdr_stream stream; 573 struct xdr_buf buf; 574 struct page *scratch; 575 struct nfs_cache_array *array; 576 unsigned int count = 0; 577 int status; 578 579 scratch = alloc_page(GFP_KERNEL); 580 if (scratch == NULL) 581 return -ENOMEM; 582 583 if (buflen == 0) 584 goto out_nopages; 585 586 xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen); 587 xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE); 588 589 do { 590 status = xdr_decode(desc, entry, &stream); 591 if (status != 0) { 592 if (status == -EAGAIN) 593 status = 0; 594 break; 595 } 596 597 count++; 598 599 if (desc->plus != 0) 600 nfs_prime_dcache(file_dentry(desc->file), entry); 601 602 status = nfs_readdir_add_to_array(entry, page); 603 if (status != 0) 604 break; 605 } while (!entry->eof); 606 607 out_nopages: 608 if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) { 609 array = nfs_readdir_get_array(page); 610 if (!IS_ERR(array)) { 611 array->eof_index = array->size; 612 status = 0; 613 nfs_readdir_release_array(page); 614 } else 615 status = PTR_ERR(array); 616 } 617 618 put_page(scratch); 619 return status; 620 } 621 622 static 623 void nfs_readdir_free_pages(struct page **pages, unsigned int npages) 624 { 625 unsigned int i; 626 for (i = 0; i < npages; i++) 627 put_page(pages[i]); 628 } 629 630 /* 631 * nfs_readdir_large_page will allocate pages that must be freed with a call 632 * to nfs_readdir_free_pagearray 633 */ 634 static 635 int nfs_readdir_alloc_pages(struct page **pages, unsigned int npages) 636 { 637 unsigned int i; 638 639 for (i = 0; i < npages; i++) { 640 struct page *page = alloc_page(GFP_KERNEL); 641 if (page == NULL) 642 goto out_freepages; 643 pages[i] = page; 644 } 645 return 0; 646 647 out_freepages: 648 nfs_readdir_free_pages(pages, i); 649 return -ENOMEM; 650 } 651 652 static 653 int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode) 654 { 655 struct page *pages[NFS_MAX_READDIR_PAGES]; 656 struct nfs_entry entry; 657 struct file *file = desc->file; 658 struct nfs_cache_array *array; 659 int status = -ENOMEM; 660 unsigned int array_size = ARRAY_SIZE(pages); 661 662 entry.prev_cookie = 0; 663 entry.cookie = desc->last_cookie; 664 entry.eof = 0; 665 entry.fh = nfs_alloc_fhandle(); 666 entry.fattr = nfs_alloc_fattr(); 667 entry.server = NFS_SERVER(inode); 668 if (entry.fh == NULL || entry.fattr == NULL) 669 goto out; 670 671 entry.label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT); 672 if (IS_ERR(entry.label)) { 673 status = PTR_ERR(entry.label); 674 goto out; 675 } 676 677 array = nfs_readdir_get_array(page); 678 if (IS_ERR(array)) { 679 status = PTR_ERR(array); 680 goto out_label_free; 681 } 682 memset(array, 0, sizeof(struct nfs_cache_array)); 683 atomic_set(&array->refcount, 1); 684 array->eof_index = -1; 685 686 status = nfs_readdir_alloc_pages(pages, array_size); 687 if (status < 0) 688 goto out_release_array; 689 do { 690 unsigned int pglen; 691 status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode); 692 693 if (status < 0) 694 break; 695 pglen = status; 696 status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen); 697 if (status < 0) { 698 if (status == -ENOSPC) 699 status = 0; 700 break; 701 } 702 } while (array->eof_index < 0); 703 704 nfs_readdir_free_pages(pages, array_size); 705 out_release_array: 706 nfs_readdir_release_array(page); 707 out_label_free: 708 nfs4_label_free(entry.label); 709 out: 710 nfs_free_fattr(entry.fattr); 711 nfs_free_fhandle(entry.fh); 712 return status; 713 } 714 715 /* 716 * Now we cache directories properly, by converting xdr information 717 * to an array that can be used for lookups later. This results in 718 * fewer cache pages, since we can store more information on each page. 719 * We only need to convert from xdr once so future lookups are much simpler 720 */ 721 static 722 int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page) 723 { 724 struct inode *inode = file_inode(desc->file); 725 int ret; 726 727 ret = nfs_readdir_xdr_to_array(desc, page, inode); 728 if (ret < 0) 729 goto error; 730 SetPageUptodate(page); 731 732 if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) { 733 /* Should never happen */ 734 nfs_zap_mapping(inode, inode->i_mapping); 735 } 736 unlock_page(page); 737 return 0; 738 error: 739 unlock_page(page); 740 return ret; 741 } 742 743 static 744 void cache_page_release(nfs_readdir_descriptor_t *desc) 745 { 746 nfs_readdir_clear_array(desc->page); 747 put_page(desc->page); 748 desc->page = NULL; 749 } 750 751 static 752 struct page *get_cache_page(nfs_readdir_descriptor_t *desc) 753 { 754 struct page *page; 755 756 for (;;) { 757 page = read_cache_page(desc->file->f_mapping, 758 desc->page_index, (filler_t *)nfs_readdir_filler, desc); 759 if (IS_ERR(page) || grab_page(page)) 760 break; 761 put_page(page); 762 } 763 return page; 764 } 765 766 /* 767 * Returns 0 if desc->dir_cookie was found on page desc->page_index 768 */ 769 static 770 int find_cache_page(nfs_readdir_descriptor_t *desc) 771 { 772 int res; 773 774 desc->page = get_cache_page(desc); 775 if (IS_ERR(desc->page)) 776 return PTR_ERR(desc->page); 777 778 res = nfs_readdir_search_array(desc); 779 if (res != 0) 780 cache_page_release(desc); 781 return res; 782 } 783 784 /* Search for desc->dir_cookie from the beginning of the page cache */ 785 static inline 786 int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) 787 { 788 int res; 789 790 if (desc->page_index == 0) { 791 desc->current_index = 0; 792 desc->last_cookie = 0; 793 } 794 do { 795 res = find_cache_page(desc); 796 } while (res == -EAGAIN); 797 return res; 798 } 799 800 /* 801 * Once we've found the start of the dirent within a page: fill 'er up... 802 */ 803 static 804 int nfs_do_filldir(nfs_readdir_descriptor_t *desc) 805 { 806 struct file *file = desc->file; 807 int i = 0; 808 int res = 0; 809 struct nfs_cache_array *array = NULL; 810 struct nfs_open_dir_context *ctx = file->private_data; 811 812 array = nfs_readdir_get_array(desc->page); 813 if (IS_ERR(array)) { 814 res = PTR_ERR(array); 815 goto out; 816 } 817 818 for (i = desc->cache_entry_index; i < array->size; i++) { 819 struct nfs_cache_array_entry *ent; 820 821 ent = &array->array[i]; 822 if (!dir_emit(desc->ctx, ent->string.name, ent->string.len, 823 nfs_compat_user_ino64(ent->ino), ent->d_type)) { 824 desc->eof = 1; 825 break; 826 } 827 desc->ctx->pos++; 828 if (i < (array->size-1)) 829 *desc->dir_cookie = array->array[i+1].cookie; 830 else 831 *desc->dir_cookie = array->last_cookie; 832 if (ctx->duped != 0) 833 ctx->duped = 1; 834 } 835 if (array->eof_index >= 0) 836 desc->eof = 1; 837 838 nfs_readdir_release_array(desc->page); 839 out: 840 cache_page_release(desc); 841 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", 842 (unsigned long long)*desc->dir_cookie, res); 843 return res; 844 } 845 846 /* 847 * If we cannot find a cookie in our cache, we suspect that this is 848 * because it points to a deleted file, so we ask the server to return 849 * whatever it thinks is the next entry. We then feed this to filldir. 850 * If all goes well, we should then be able to find our way round the 851 * cache on the next call to readdir_search_pagecache(); 852 * 853 * NOTE: we cannot add the anonymous page to the pagecache because 854 * the data it contains might not be page aligned. Besides, 855 * we should already have a complete representation of the 856 * directory in the page cache by the time we get here. 857 */ 858 static inline 859 int uncached_readdir(nfs_readdir_descriptor_t *desc) 860 { 861 struct page *page = NULL; 862 int status; 863 struct inode *inode = file_inode(desc->file); 864 struct nfs_open_dir_context *ctx = desc->file->private_data; 865 866 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n", 867 (unsigned long long)*desc->dir_cookie); 868 869 page = alloc_page(GFP_HIGHUSER); 870 if (!page) { 871 status = -ENOMEM; 872 goto out; 873 } 874 875 desc->page_index = 0; 876 desc->last_cookie = *desc->dir_cookie; 877 desc->page = page; 878 ctx->duped = 0; 879 880 status = nfs_readdir_xdr_to_array(desc, page, inode); 881 if (status < 0) 882 goto out_release; 883 884 status = nfs_do_filldir(desc); 885 886 out: 887 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", 888 __func__, status); 889 return status; 890 out_release: 891 cache_page_release(desc); 892 goto out; 893 } 894 895 /* The file offset position represents the dirent entry number. A 896 last cookie cache takes care of the common case of reading the 897 whole directory. 898 */ 899 static int nfs_readdir(struct file *file, struct dir_context *ctx) 900 { 901 struct dentry *dentry = file_dentry(file); 902 struct inode *inode = d_inode(dentry); 903 nfs_readdir_descriptor_t my_desc, 904 *desc = &my_desc; 905 struct nfs_open_dir_context *dir_ctx = file->private_data; 906 int res = 0; 907 908 dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n", 909 file, (long long)ctx->pos); 910 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); 911 912 /* 913 * ctx->pos points to the dirent entry number. 914 * *desc->dir_cookie has the cookie for the next entry. We have 915 * to either find the entry with the appropriate number or 916 * revalidate the cookie. 917 */ 918 memset(desc, 0, sizeof(*desc)); 919 920 desc->file = file; 921 desc->ctx = ctx; 922 desc->dir_cookie = &dir_ctx->dir_cookie; 923 desc->decode = NFS_PROTO(inode)->decode_dirent; 924 desc->plus = nfs_use_readdirplus(inode, ctx) ? 1 : 0; 925 926 if (ctx->pos == 0 || nfs_attribute_cache_expired(inode)) 927 res = nfs_revalidate_mapping(inode, file->f_mapping); 928 if (res < 0) 929 goto out; 930 931 do { 932 res = readdir_search_pagecache(desc); 933 934 if (res == -EBADCOOKIE) { 935 res = 0; 936 /* This means either end of directory */ 937 if (*desc->dir_cookie && desc->eof == 0) { 938 /* Or that the server has 'lost' a cookie */ 939 res = uncached_readdir(desc); 940 if (res == 0) 941 continue; 942 } 943 break; 944 } 945 if (res == -ETOOSMALL && desc->plus) { 946 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 947 nfs_zap_caches(inode); 948 desc->page_index = 0; 949 desc->plus = 0; 950 desc->eof = 0; 951 continue; 952 } 953 if (res < 0) 954 break; 955 956 res = nfs_do_filldir(desc); 957 if (res < 0) 958 break; 959 } while (!desc->eof); 960 out: 961 if (res > 0) 962 res = 0; 963 dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res); 964 return res; 965 } 966 967 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) 968 { 969 struct nfs_open_dir_context *dir_ctx = filp->private_data; 970 971 dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n", 972 filp, offset, whence); 973 974 switch (whence) { 975 case 1: 976 offset += filp->f_pos; 977 case 0: 978 if (offset >= 0) 979 break; 980 default: 981 return -EINVAL; 982 } 983 if (offset != filp->f_pos) { 984 filp->f_pos = offset; 985 dir_ctx->dir_cookie = 0; 986 dir_ctx->duped = 0; 987 } 988 return offset; 989 } 990 991 /* 992 * All directory operations under NFS are synchronous, so fsync() 993 * is a dummy operation. 994 */ 995 static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end, 996 int datasync) 997 { 998 struct inode *inode = file_inode(filp); 999 1000 dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync); 1001 1002 inode_lock(inode); 1003 nfs_inc_stats(inode, NFSIOS_VFSFSYNC); 1004 inode_unlock(inode); 1005 return 0; 1006 } 1007 1008 /** 1009 * nfs_force_lookup_revalidate - Mark the directory as having changed 1010 * @dir - pointer to directory inode 1011 * 1012 * This forces the revalidation code in nfs_lookup_revalidate() to do a 1013 * full lookup on all child dentries of 'dir' whenever a change occurs 1014 * on the server that might have invalidated our dcache. 1015 * 1016 * The caller should be holding dir->i_lock 1017 */ 1018 void nfs_force_lookup_revalidate(struct inode *dir) 1019 { 1020 NFS_I(dir)->cache_change_attribute++; 1021 } 1022 EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate); 1023 1024 /* 1025 * A check for whether or not the parent directory has changed. 1026 * In the case it has, we assume that the dentries are untrustworthy 1027 * and may need to be looked up again. 1028 * If rcu_walk prevents us from performing a full check, return 0. 1029 */ 1030 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry, 1031 int rcu_walk) 1032 { 1033 if (IS_ROOT(dentry)) 1034 return 1; 1035 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE) 1036 return 0; 1037 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 1038 return 0; 1039 /* Revalidate nfsi->cache_change_attribute before we declare a match */ 1040 if (nfs_mapping_need_revalidate_inode(dir)) { 1041 if (rcu_walk) 1042 return 0; 1043 if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) 1044 return 0; 1045 } 1046 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 1047 return 0; 1048 return 1; 1049 } 1050 1051 /* 1052 * Use intent information to check whether or not we're going to do 1053 * an O_EXCL create using this path component. 1054 */ 1055 static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags) 1056 { 1057 if (NFS_PROTO(dir)->version == 2) 1058 return 0; 1059 return flags & LOOKUP_EXCL; 1060 } 1061 1062 /* 1063 * Inode and filehandle revalidation for lookups. 1064 * 1065 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, 1066 * or if the intent information indicates that we're about to open this 1067 * particular file and the "nocto" mount flag is not set. 1068 * 1069 */ 1070 static 1071 int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags) 1072 { 1073 struct nfs_server *server = NFS_SERVER(inode); 1074 int ret; 1075 1076 if (IS_AUTOMOUNT(inode)) 1077 return 0; 1078 /* VFS wants an on-the-wire revalidation */ 1079 if (flags & LOOKUP_REVAL) 1080 goto out_force; 1081 /* This is an open(2) */ 1082 if ((flags & LOOKUP_OPEN) && !(server->flags & NFS_MOUNT_NOCTO) && 1083 (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) 1084 goto out_force; 1085 out: 1086 return (inode->i_nlink == 0) ? -ENOENT : 0; 1087 out_force: 1088 if (flags & LOOKUP_RCU) 1089 return -ECHILD; 1090 ret = __nfs_revalidate_inode(server, inode); 1091 if (ret != 0) 1092 return ret; 1093 goto out; 1094 } 1095 1096 /* 1097 * We judge how long we want to trust negative 1098 * dentries by looking at the parent inode mtime. 1099 * 1100 * If parent mtime has changed, we revalidate, else we wait for a 1101 * period corresponding to the parent's attribute cache timeout value. 1102 * 1103 * If LOOKUP_RCU prevents us from performing a full check, return 1 1104 * suggesting a reval is needed. 1105 */ 1106 static inline 1107 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 1108 unsigned int flags) 1109 { 1110 /* Don't revalidate a negative dentry if we're creating a new file */ 1111 if (flags & LOOKUP_CREATE) 1112 return 0; 1113 if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) 1114 return 1; 1115 return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU); 1116 } 1117 1118 /* 1119 * This is called every time the dcache has a lookup hit, 1120 * and we should check whether we can really trust that 1121 * lookup. 1122 * 1123 * NOTE! The hit can be a negative hit too, don't assume 1124 * we have an inode! 1125 * 1126 * If the parent directory is seen to have changed, we throw out the 1127 * cached dentry and do a new lookup. 1128 */ 1129 static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags) 1130 { 1131 struct inode *dir; 1132 struct inode *inode; 1133 struct dentry *parent; 1134 struct nfs_fh *fhandle = NULL; 1135 struct nfs_fattr *fattr = NULL; 1136 struct nfs4_label *label = NULL; 1137 int error; 1138 1139 if (flags & LOOKUP_RCU) { 1140 parent = ACCESS_ONCE(dentry->d_parent); 1141 dir = d_inode_rcu(parent); 1142 if (!dir) 1143 return -ECHILD; 1144 } else { 1145 parent = dget_parent(dentry); 1146 dir = d_inode(parent); 1147 } 1148 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); 1149 inode = d_inode(dentry); 1150 1151 if (!inode) { 1152 if (nfs_neg_need_reval(dir, dentry, flags)) { 1153 if (flags & LOOKUP_RCU) 1154 return -ECHILD; 1155 goto out_bad; 1156 } 1157 goto out_valid; 1158 } 1159 1160 if (is_bad_inode(inode)) { 1161 if (flags & LOOKUP_RCU) 1162 return -ECHILD; 1163 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", 1164 __func__, dentry); 1165 goto out_bad; 1166 } 1167 1168 if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ)) 1169 goto out_set_verifier; 1170 1171 /* Force a full look up iff the parent directory has changed */ 1172 if (!nfs_is_exclusive_create(dir, flags) && 1173 nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) { 1174 1175 if (nfs_lookup_verify_inode(inode, flags)) { 1176 if (flags & LOOKUP_RCU) 1177 return -ECHILD; 1178 goto out_zap_parent; 1179 } 1180 nfs_advise_use_readdirplus(dir); 1181 goto out_valid; 1182 } 1183 1184 if (flags & LOOKUP_RCU) 1185 return -ECHILD; 1186 1187 if (NFS_STALE(inode)) 1188 goto out_bad; 1189 1190 error = -ENOMEM; 1191 fhandle = nfs_alloc_fhandle(); 1192 fattr = nfs_alloc_fattr(); 1193 if (fhandle == NULL || fattr == NULL) 1194 goto out_error; 1195 1196 label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT); 1197 if (IS_ERR(label)) 1198 goto out_error; 1199 1200 trace_nfs_lookup_revalidate_enter(dir, dentry, flags); 1201 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label); 1202 trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error); 1203 if (error) 1204 goto out_bad; 1205 if (nfs_compare_fh(NFS_FH(inode), fhandle)) 1206 goto out_bad; 1207 if ((error = nfs_refresh_inode(inode, fattr)) != 0) 1208 goto out_bad; 1209 1210 nfs_setsecurity(inode, fattr, label); 1211 1212 nfs_free_fattr(fattr); 1213 nfs_free_fhandle(fhandle); 1214 nfs4_label_free(label); 1215 1216 /* set a readdirplus hint that we had a cache miss */ 1217 nfs_force_use_readdirplus(dir); 1218 1219 out_set_verifier: 1220 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1221 out_valid: 1222 if (flags & LOOKUP_RCU) { 1223 if (parent != ACCESS_ONCE(dentry->d_parent)) 1224 return -ECHILD; 1225 } else 1226 dput(parent); 1227 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n", 1228 __func__, dentry); 1229 return 1; 1230 out_zap_parent: 1231 nfs_zap_caches(dir); 1232 out_bad: 1233 WARN_ON(flags & LOOKUP_RCU); 1234 nfs_free_fattr(fattr); 1235 nfs_free_fhandle(fhandle); 1236 nfs4_label_free(label); 1237 nfs_mark_for_revalidate(dir); 1238 if (inode && S_ISDIR(inode->i_mode)) { 1239 /* Purge readdir caches. */ 1240 nfs_zap_caches(inode); 1241 /* 1242 * We can't d_drop the root of a disconnected tree: 1243 * its d_hash is on the s_anon list and d_drop() would hide 1244 * it from shrink_dcache_for_unmount(), leading to busy 1245 * inodes on unmount and further oopses. 1246 */ 1247 if (IS_ROOT(dentry)) 1248 goto out_valid; 1249 } 1250 dput(parent); 1251 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n", 1252 __func__, dentry); 1253 return 0; 1254 out_error: 1255 WARN_ON(flags & LOOKUP_RCU); 1256 nfs_free_fattr(fattr); 1257 nfs_free_fhandle(fhandle); 1258 nfs4_label_free(label); 1259 dput(parent); 1260 dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n", 1261 __func__, dentry, error); 1262 return error; 1263 } 1264 1265 /* 1266 * A weaker form of d_revalidate for revalidating just the d_inode(dentry) 1267 * when we don't really care about the dentry name. This is called when a 1268 * pathwalk ends on a dentry that was not found via a normal lookup in the 1269 * parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals). 1270 * 1271 * In this situation, we just want to verify that the inode itself is OK 1272 * since the dentry might have changed on the server. 1273 */ 1274 static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags) 1275 { 1276 int error; 1277 struct inode *inode = d_inode(dentry); 1278 1279 /* 1280 * I believe we can only get a negative dentry here in the case of a 1281 * procfs-style symlink. Just assume it's correct for now, but we may 1282 * eventually need to do something more here. 1283 */ 1284 if (!inode) { 1285 dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n", 1286 __func__, dentry); 1287 return 1; 1288 } 1289 1290 if (is_bad_inode(inode)) { 1291 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n", 1292 __func__, dentry); 1293 return 0; 1294 } 1295 1296 error = nfs_revalidate_inode(NFS_SERVER(inode), inode); 1297 dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n", 1298 __func__, inode->i_ino, error ? "invalid" : "valid"); 1299 return !error; 1300 } 1301 1302 /* 1303 * This is called from dput() when d_count is going to 0. 1304 */ 1305 static int nfs_dentry_delete(const struct dentry *dentry) 1306 { 1307 dfprintk(VFS, "NFS: dentry_delete(%pd2, %x)\n", 1308 dentry, dentry->d_flags); 1309 1310 /* Unhash any dentry with a stale inode */ 1311 if (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry))) 1312 return 1; 1313 1314 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1315 /* Unhash it, so that ->d_iput() would be called */ 1316 return 1; 1317 } 1318 if (!(dentry->d_sb->s_flags & MS_ACTIVE)) { 1319 /* Unhash it, so that ancestors of killed async unlink 1320 * files will be cleaned up during umount */ 1321 return 1; 1322 } 1323 return 0; 1324 1325 } 1326 1327 /* Ensure that we revalidate inode->i_nlink */ 1328 static void nfs_drop_nlink(struct inode *inode) 1329 { 1330 spin_lock(&inode->i_lock); 1331 /* drop the inode if we're reasonably sure this is the last link */ 1332 if (inode->i_nlink == 1) 1333 clear_nlink(inode); 1334 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATTR; 1335 spin_unlock(&inode->i_lock); 1336 } 1337 1338 /* 1339 * Called when the dentry loses inode. 1340 * We use it to clean up silly-renamed files. 1341 */ 1342 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) 1343 { 1344 if (S_ISDIR(inode->i_mode)) 1345 /* drop any readdir cache as it could easily be old */ 1346 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA; 1347 1348 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1349 nfs_complete_unlink(dentry, inode); 1350 nfs_drop_nlink(inode); 1351 } 1352 iput(inode); 1353 } 1354 1355 static void nfs_d_release(struct dentry *dentry) 1356 { 1357 /* free cached devname value, if it survived that far */ 1358 if (unlikely(dentry->d_fsdata)) { 1359 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 1360 WARN_ON(1); 1361 else 1362 kfree(dentry->d_fsdata); 1363 } 1364 } 1365 1366 const struct dentry_operations nfs_dentry_operations = { 1367 .d_revalidate = nfs_lookup_revalidate, 1368 .d_weak_revalidate = nfs_weak_revalidate, 1369 .d_delete = nfs_dentry_delete, 1370 .d_iput = nfs_dentry_iput, 1371 .d_automount = nfs_d_automount, 1372 .d_release = nfs_d_release, 1373 }; 1374 EXPORT_SYMBOL_GPL(nfs_dentry_operations); 1375 1376 struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) 1377 { 1378 struct dentry *res; 1379 struct inode *inode = NULL; 1380 struct nfs_fh *fhandle = NULL; 1381 struct nfs_fattr *fattr = NULL; 1382 struct nfs4_label *label = NULL; 1383 int error; 1384 1385 dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry); 1386 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); 1387 1388 if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen)) 1389 return ERR_PTR(-ENAMETOOLONG); 1390 1391 /* 1392 * If we're doing an exclusive create, optimize away the lookup 1393 * but don't hash the dentry. 1394 */ 1395 if (nfs_is_exclusive_create(dir, flags)) 1396 return NULL; 1397 1398 res = ERR_PTR(-ENOMEM); 1399 fhandle = nfs_alloc_fhandle(); 1400 fattr = nfs_alloc_fattr(); 1401 if (fhandle == NULL || fattr == NULL) 1402 goto out; 1403 1404 label = nfs4_label_alloc(NFS_SERVER(dir), GFP_NOWAIT); 1405 if (IS_ERR(label)) 1406 goto out; 1407 1408 trace_nfs_lookup_enter(dir, dentry, flags); 1409 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label); 1410 if (error == -ENOENT) 1411 goto no_entry; 1412 if (error < 0) { 1413 res = ERR_PTR(error); 1414 goto out_label; 1415 } 1416 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); 1417 res = ERR_CAST(inode); 1418 if (IS_ERR(res)) 1419 goto out_label; 1420 1421 /* Notify readdir to use READDIRPLUS */ 1422 nfs_force_use_readdirplus(dir); 1423 1424 no_entry: 1425 res = d_splice_alias(inode, dentry); 1426 if (res != NULL) { 1427 if (IS_ERR(res)) 1428 goto out_label; 1429 dentry = res; 1430 } 1431 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1432 out_label: 1433 trace_nfs_lookup_exit(dir, dentry, flags, error); 1434 nfs4_label_free(label); 1435 out: 1436 nfs_free_fattr(fattr); 1437 nfs_free_fhandle(fhandle); 1438 return res; 1439 } 1440 EXPORT_SYMBOL_GPL(nfs_lookup); 1441 1442 #if IS_ENABLED(CONFIG_NFS_V4) 1443 static int nfs4_lookup_revalidate(struct dentry *, unsigned int); 1444 1445 const struct dentry_operations nfs4_dentry_operations = { 1446 .d_revalidate = nfs4_lookup_revalidate, 1447 .d_delete = nfs_dentry_delete, 1448 .d_iput = nfs_dentry_iput, 1449 .d_automount = nfs_d_automount, 1450 .d_release = nfs_d_release, 1451 }; 1452 EXPORT_SYMBOL_GPL(nfs4_dentry_operations); 1453 1454 static fmode_t flags_to_mode(int flags) 1455 { 1456 fmode_t res = (__force fmode_t)flags & FMODE_EXEC; 1457 if ((flags & O_ACCMODE) != O_WRONLY) 1458 res |= FMODE_READ; 1459 if ((flags & O_ACCMODE) != O_RDONLY) 1460 res |= FMODE_WRITE; 1461 return res; 1462 } 1463 1464 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp) 1465 { 1466 return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp); 1467 } 1468 1469 static int do_open(struct inode *inode, struct file *filp) 1470 { 1471 nfs_fscache_open_file(inode, filp); 1472 return 0; 1473 } 1474 1475 static int nfs_finish_open(struct nfs_open_context *ctx, 1476 struct dentry *dentry, 1477 struct file *file, unsigned open_flags, 1478 int *opened) 1479 { 1480 int err; 1481 1482 err = finish_open(file, dentry, do_open, opened); 1483 if (err) 1484 goto out; 1485 nfs_file_set_open_context(file, ctx); 1486 1487 out: 1488 return err; 1489 } 1490 1491 int nfs_atomic_open(struct inode *dir, struct dentry *dentry, 1492 struct file *file, unsigned open_flags, 1493 umode_t mode, int *opened) 1494 { 1495 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 1496 struct nfs_open_context *ctx; 1497 struct dentry *res; 1498 struct iattr attr = { .ia_valid = ATTR_OPEN }; 1499 struct inode *inode; 1500 unsigned int lookup_flags = 0; 1501 bool switched = false; 1502 int err; 1503 1504 /* Expect a negative dentry */ 1505 BUG_ON(d_inode(dentry)); 1506 1507 dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n", 1508 dir->i_sb->s_id, dir->i_ino, dentry); 1509 1510 err = nfs_check_flags(open_flags); 1511 if (err) 1512 return err; 1513 1514 /* NFS only supports OPEN on regular files */ 1515 if ((open_flags & O_DIRECTORY)) { 1516 if (!d_in_lookup(dentry)) { 1517 /* 1518 * Hashed negative dentry with O_DIRECTORY: dentry was 1519 * revalidated and is fine, no need to perform lookup 1520 * again 1521 */ 1522 return -ENOENT; 1523 } 1524 lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY; 1525 goto no_open; 1526 } 1527 1528 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 1529 return -ENAMETOOLONG; 1530 1531 if (open_flags & O_CREAT) { 1532 struct nfs_server *server = NFS_SERVER(dir); 1533 1534 if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK)) 1535 mode &= ~current_umask(); 1536 1537 attr.ia_valid |= ATTR_MODE; 1538 attr.ia_mode = mode; 1539 } 1540 if (open_flags & O_TRUNC) { 1541 attr.ia_valid |= ATTR_SIZE; 1542 attr.ia_size = 0; 1543 } 1544 1545 if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) { 1546 d_drop(dentry); 1547 switched = true; 1548 dentry = d_alloc_parallel(dentry->d_parent, 1549 &dentry->d_name, &wq); 1550 if (IS_ERR(dentry)) 1551 return PTR_ERR(dentry); 1552 if (unlikely(!d_in_lookup(dentry))) 1553 return finish_no_open(file, dentry); 1554 } 1555 1556 ctx = create_nfs_open_context(dentry, open_flags, file); 1557 err = PTR_ERR(ctx); 1558 if (IS_ERR(ctx)) 1559 goto out; 1560 1561 trace_nfs_atomic_open_enter(dir, ctx, open_flags); 1562 inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, opened); 1563 if (IS_ERR(inode)) { 1564 err = PTR_ERR(inode); 1565 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); 1566 put_nfs_open_context(ctx); 1567 d_drop(dentry); 1568 switch (err) { 1569 case -ENOENT: 1570 d_add(dentry, NULL); 1571 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1572 break; 1573 case -EISDIR: 1574 case -ENOTDIR: 1575 goto no_open; 1576 case -ELOOP: 1577 if (!(open_flags & O_NOFOLLOW)) 1578 goto no_open; 1579 break; 1580 /* case -EINVAL: */ 1581 default: 1582 break; 1583 } 1584 goto out; 1585 } 1586 1587 err = nfs_finish_open(ctx, ctx->dentry, file, open_flags, opened); 1588 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); 1589 put_nfs_open_context(ctx); 1590 out: 1591 if (unlikely(switched)) { 1592 d_lookup_done(dentry); 1593 dput(dentry); 1594 } 1595 return err; 1596 1597 no_open: 1598 res = nfs_lookup(dir, dentry, lookup_flags); 1599 if (switched) { 1600 d_lookup_done(dentry); 1601 if (!res) 1602 res = dentry; 1603 else 1604 dput(dentry); 1605 } 1606 if (IS_ERR(res)) 1607 return PTR_ERR(res); 1608 return finish_no_open(file, res); 1609 } 1610 EXPORT_SYMBOL_GPL(nfs_atomic_open); 1611 1612 static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) 1613 { 1614 struct inode *inode; 1615 int ret = 0; 1616 1617 if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY)) 1618 goto no_open; 1619 if (d_mountpoint(dentry)) 1620 goto no_open; 1621 if (NFS_SB(dentry->d_sb)->caps & NFS_CAP_ATOMIC_OPEN_V1) 1622 goto no_open; 1623 1624 inode = d_inode(dentry); 1625 1626 /* We can't create new files in nfs_open_revalidate(), so we 1627 * optimize away revalidation of negative dentries. 1628 */ 1629 if (inode == NULL) { 1630 struct dentry *parent; 1631 struct inode *dir; 1632 1633 if (flags & LOOKUP_RCU) { 1634 parent = ACCESS_ONCE(dentry->d_parent); 1635 dir = d_inode_rcu(parent); 1636 if (!dir) 1637 return -ECHILD; 1638 } else { 1639 parent = dget_parent(dentry); 1640 dir = d_inode(parent); 1641 } 1642 if (!nfs_neg_need_reval(dir, dentry, flags)) 1643 ret = 1; 1644 else if (flags & LOOKUP_RCU) 1645 ret = -ECHILD; 1646 if (!(flags & LOOKUP_RCU)) 1647 dput(parent); 1648 else if (parent != ACCESS_ONCE(dentry->d_parent)) 1649 return -ECHILD; 1650 goto out; 1651 } 1652 1653 /* NFS only supports OPEN on regular files */ 1654 if (!S_ISREG(inode->i_mode)) 1655 goto no_open; 1656 /* We cannot do exclusive creation on a positive dentry */ 1657 if (flags & LOOKUP_EXCL) 1658 goto no_open; 1659 1660 /* Let f_op->open() actually open (and revalidate) the file */ 1661 ret = 1; 1662 1663 out: 1664 return ret; 1665 1666 no_open: 1667 return nfs_lookup_revalidate(dentry, flags); 1668 } 1669 1670 #endif /* CONFIG_NFSV4 */ 1671 1672 /* 1673 * Code common to create, mkdir, and mknod. 1674 */ 1675 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, 1676 struct nfs_fattr *fattr, 1677 struct nfs4_label *label) 1678 { 1679 struct dentry *parent = dget_parent(dentry); 1680 struct inode *dir = d_inode(parent); 1681 struct inode *inode; 1682 int error = -EACCES; 1683 1684 d_drop(dentry); 1685 1686 /* We may have been initialized further down */ 1687 if (d_really_is_positive(dentry)) 1688 goto out; 1689 if (fhandle->size == 0) { 1690 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, NULL); 1691 if (error) 1692 goto out_error; 1693 } 1694 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1695 if (!(fattr->valid & NFS_ATTR_FATTR)) { 1696 struct nfs_server *server = NFS_SB(dentry->d_sb); 1697 error = server->nfs_client->rpc_ops->getattr(server, fhandle, fattr, NULL); 1698 if (error < 0) 1699 goto out_error; 1700 } 1701 inode = nfs_fhget(dentry->d_sb, fhandle, fattr, label); 1702 error = PTR_ERR(inode); 1703 if (IS_ERR(inode)) 1704 goto out_error; 1705 d_add(dentry, inode); 1706 out: 1707 dput(parent); 1708 return 0; 1709 out_error: 1710 nfs_mark_for_revalidate(dir); 1711 dput(parent); 1712 return error; 1713 } 1714 EXPORT_SYMBOL_GPL(nfs_instantiate); 1715 1716 /* 1717 * Following a failed create operation, we drop the dentry rather 1718 * than retain a negative dentry. This avoids a problem in the event 1719 * that the operation succeeded on the server, but an error in the 1720 * reply path made it appear to have failed. 1721 */ 1722 int nfs_create(struct inode *dir, struct dentry *dentry, 1723 umode_t mode, bool excl) 1724 { 1725 struct iattr attr; 1726 int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT; 1727 int error; 1728 1729 dfprintk(VFS, "NFS: create(%s/%lu), %pd\n", 1730 dir->i_sb->s_id, dir->i_ino, dentry); 1731 1732 attr.ia_mode = mode; 1733 attr.ia_valid = ATTR_MODE; 1734 1735 trace_nfs_create_enter(dir, dentry, open_flags); 1736 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags); 1737 trace_nfs_create_exit(dir, dentry, open_flags, error); 1738 if (error != 0) 1739 goto out_err; 1740 return 0; 1741 out_err: 1742 d_drop(dentry); 1743 return error; 1744 } 1745 EXPORT_SYMBOL_GPL(nfs_create); 1746 1747 /* 1748 * See comments for nfs_proc_create regarding failed operations. 1749 */ 1750 int 1751 nfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev) 1752 { 1753 struct iattr attr; 1754 int status; 1755 1756 dfprintk(VFS, "NFS: mknod(%s/%lu), %pd\n", 1757 dir->i_sb->s_id, dir->i_ino, dentry); 1758 1759 attr.ia_mode = mode; 1760 attr.ia_valid = ATTR_MODE; 1761 1762 trace_nfs_mknod_enter(dir, dentry); 1763 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); 1764 trace_nfs_mknod_exit(dir, dentry, status); 1765 if (status != 0) 1766 goto out_err; 1767 return 0; 1768 out_err: 1769 d_drop(dentry); 1770 return status; 1771 } 1772 EXPORT_SYMBOL_GPL(nfs_mknod); 1773 1774 /* 1775 * See comments for nfs_proc_create regarding failed operations. 1776 */ 1777 int nfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 1778 { 1779 struct iattr attr; 1780 int error; 1781 1782 dfprintk(VFS, "NFS: mkdir(%s/%lu), %pd\n", 1783 dir->i_sb->s_id, dir->i_ino, dentry); 1784 1785 attr.ia_valid = ATTR_MODE; 1786 attr.ia_mode = mode | S_IFDIR; 1787 1788 trace_nfs_mkdir_enter(dir, dentry); 1789 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); 1790 trace_nfs_mkdir_exit(dir, dentry, error); 1791 if (error != 0) 1792 goto out_err; 1793 return 0; 1794 out_err: 1795 d_drop(dentry); 1796 return error; 1797 } 1798 EXPORT_SYMBOL_GPL(nfs_mkdir); 1799 1800 static void nfs_dentry_handle_enoent(struct dentry *dentry) 1801 { 1802 if (simple_positive(dentry)) 1803 d_delete(dentry); 1804 } 1805 1806 int nfs_rmdir(struct inode *dir, struct dentry *dentry) 1807 { 1808 int error; 1809 1810 dfprintk(VFS, "NFS: rmdir(%s/%lu), %pd\n", 1811 dir->i_sb->s_id, dir->i_ino, dentry); 1812 1813 trace_nfs_rmdir_enter(dir, dentry); 1814 if (d_really_is_positive(dentry)) { 1815 down_write(&NFS_I(d_inode(dentry))->rmdir_sem); 1816 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 1817 /* Ensure the VFS deletes this inode */ 1818 switch (error) { 1819 case 0: 1820 clear_nlink(d_inode(dentry)); 1821 break; 1822 case -ENOENT: 1823 nfs_dentry_handle_enoent(dentry); 1824 } 1825 up_write(&NFS_I(d_inode(dentry))->rmdir_sem); 1826 } else 1827 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 1828 trace_nfs_rmdir_exit(dir, dentry, error); 1829 1830 return error; 1831 } 1832 EXPORT_SYMBOL_GPL(nfs_rmdir); 1833 1834 /* 1835 * Remove a file after making sure there are no pending writes, 1836 * and after checking that the file has only one user. 1837 * 1838 * We invalidate the attribute cache and free the inode prior to the operation 1839 * to avoid possible races if the server reuses the inode. 1840 */ 1841 static int nfs_safe_remove(struct dentry *dentry) 1842 { 1843 struct inode *dir = d_inode(dentry->d_parent); 1844 struct inode *inode = d_inode(dentry); 1845 int error = -EBUSY; 1846 1847 dfprintk(VFS, "NFS: safe_remove(%pd2)\n", dentry); 1848 1849 /* If the dentry was sillyrenamed, we simply call d_delete() */ 1850 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1851 error = 0; 1852 goto out; 1853 } 1854 1855 trace_nfs_remove_enter(dir, dentry); 1856 if (inode != NULL) { 1857 NFS_PROTO(inode)->return_delegation(inode); 1858 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1859 if (error == 0) 1860 nfs_drop_nlink(inode); 1861 } else 1862 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1863 if (error == -ENOENT) 1864 nfs_dentry_handle_enoent(dentry); 1865 trace_nfs_remove_exit(dir, dentry, error); 1866 out: 1867 return error; 1868 } 1869 1870 /* We do silly rename. In case sillyrename() returns -EBUSY, the inode 1871 * belongs to an active ".nfs..." file and we return -EBUSY. 1872 * 1873 * If sillyrename() returns 0, we do nothing, otherwise we unlink. 1874 */ 1875 int nfs_unlink(struct inode *dir, struct dentry *dentry) 1876 { 1877 int error; 1878 int need_rehash = 0; 1879 1880 dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id, 1881 dir->i_ino, dentry); 1882 1883 trace_nfs_unlink_enter(dir, dentry); 1884 spin_lock(&dentry->d_lock); 1885 if (d_count(dentry) > 1) { 1886 spin_unlock(&dentry->d_lock); 1887 /* Start asynchronous writeout of the inode */ 1888 write_inode_now(d_inode(dentry), 0); 1889 error = nfs_sillyrename(dir, dentry); 1890 goto out; 1891 } 1892 if (!d_unhashed(dentry)) { 1893 __d_drop(dentry); 1894 need_rehash = 1; 1895 } 1896 spin_unlock(&dentry->d_lock); 1897 error = nfs_safe_remove(dentry); 1898 if (!error || error == -ENOENT) { 1899 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1900 } else if (need_rehash) 1901 d_rehash(dentry); 1902 out: 1903 trace_nfs_unlink_exit(dir, dentry, error); 1904 return error; 1905 } 1906 EXPORT_SYMBOL_GPL(nfs_unlink); 1907 1908 /* 1909 * To create a symbolic link, most file systems instantiate a new inode, 1910 * add a page to it containing the path, then write it out to the disk 1911 * using prepare_write/commit_write. 1912 * 1913 * Unfortunately the NFS client can't create the in-core inode first 1914 * because it needs a file handle to create an in-core inode (see 1915 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the 1916 * symlink request has completed on the server. 1917 * 1918 * So instead we allocate a raw page, copy the symname into it, then do 1919 * the SYMLINK request with the page as the buffer. If it succeeds, we 1920 * now have a new file handle and can instantiate an in-core NFS inode 1921 * and move the raw page into its mapping. 1922 */ 1923 int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) 1924 { 1925 struct page *page; 1926 char *kaddr; 1927 struct iattr attr; 1928 unsigned int pathlen = strlen(symname); 1929 int error; 1930 1931 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id, 1932 dir->i_ino, dentry, symname); 1933 1934 if (pathlen > PAGE_SIZE) 1935 return -ENAMETOOLONG; 1936 1937 attr.ia_mode = S_IFLNK | S_IRWXUGO; 1938 attr.ia_valid = ATTR_MODE; 1939 1940 page = alloc_page(GFP_USER); 1941 if (!page) 1942 return -ENOMEM; 1943 1944 kaddr = page_address(page); 1945 memcpy(kaddr, symname, pathlen); 1946 if (pathlen < PAGE_SIZE) 1947 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); 1948 1949 trace_nfs_symlink_enter(dir, dentry); 1950 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr); 1951 trace_nfs_symlink_exit(dir, dentry, error); 1952 if (error != 0) { 1953 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n", 1954 dir->i_sb->s_id, dir->i_ino, 1955 dentry, symname, error); 1956 d_drop(dentry); 1957 __free_page(page); 1958 return error; 1959 } 1960 1961 /* 1962 * No big deal if we can't add this page to the page cache here. 1963 * READLINK will get the missing page from the server if needed. 1964 */ 1965 if (!add_to_page_cache_lru(page, d_inode(dentry)->i_mapping, 0, 1966 GFP_KERNEL)) { 1967 SetPageUptodate(page); 1968 unlock_page(page); 1969 /* 1970 * add_to_page_cache_lru() grabs an extra page refcount. 1971 * Drop it here to avoid leaking this page later. 1972 */ 1973 put_page(page); 1974 } else 1975 __free_page(page); 1976 1977 return 0; 1978 } 1979 EXPORT_SYMBOL_GPL(nfs_symlink); 1980 1981 int 1982 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 1983 { 1984 struct inode *inode = d_inode(old_dentry); 1985 int error; 1986 1987 dfprintk(VFS, "NFS: link(%pd2 -> %pd2)\n", 1988 old_dentry, dentry); 1989 1990 trace_nfs_link_enter(inode, dir, dentry); 1991 NFS_PROTO(inode)->return_delegation(inode); 1992 1993 d_drop(dentry); 1994 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 1995 if (error == 0) { 1996 ihold(inode); 1997 d_add(dentry, inode); 1998 } 1999 trace_nfs_link_exit(inode, dir, dentry, error); 2000 return error; 2001 } 2002 EXPORT_SYMBOL_GPL(nfs_link); 2003 2004 /* 2005 * RENAME 2006 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a 2007 * different file handle for the same inode after a rename (e.g. when 2008 * moving to a different directory). A fail-safe method to do so would 2009 * be to look up old_dir/old_name, create a link to new_dir/new_name and 2010 * rename the old file using the sillyrename stuff. This way, the original 2011 * file in old_dir will go away when the last process iput()s the inode. 2012 * 2013 * FIXED. 2014 * 2015 * It actually works quite well. One needs to have the possibility for 2016 * at least one ".nfs..." file in each directory the file ever gets 2017 * moved or linked to which happens automagically with the new 2018 * implementation that only depends on the dcache stuff instead of 2019 * using the inode layer 2020 * 2021 * Unfortunately, things are a little more complicated than indicated 2022 * above. For a cross-directory move, we want to make sure we can get 2023 * rid of the old inode after the operation. This means there must be 2024 * no pending writes (if it's a file), and the use count must be 1. 2025 * If these conditions are met, we can drop the dentries before doing 2026 * the rename. 2027 */ 2028 int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, 2029 struct inode *new_dir, struct dentry *new_dentry, 2030 unsigned int flags) 2031 { 2032 struct inode *old_inode = d_inode(old_dentry); 2033 struct inode *new_inode = d_inode(new_dentry); 2034 struct dentry *dentry = NULL, *rehash = NULL; 2035 struct rpc_task *task; 2036 int error = -EBUSY; 2037 2038 if (flags) 2039 return -EINVAL; 2040 2041 dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n", 2042 old_dentry, new_dentry, 2043 d_count(new_dentry)); 2044 2045 trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry); 2046 /* 2047 * For non-directories, check whether the target is busy and if so, 2048 * make a copy of the dentry and then do a silly-rename. If the 2049 * silly-rename succeeds, the copied dentry is hashed and becomes 2050 * the new target. 2051 */ 2052 if (new_inode && !S_ISDIR(new_inode->i_mode)) { 2053 /* 2054 * To prevent any new references to the target during the 2055 * rename, we unhash the dentry in advance. 2056 */ 2057 if (!d_unhashed(new_dentry)) { 2058 d_drop(new_dentry); 2059 rehash = new_dentry; 2060 } 2061 2062 if (d_count(new_dentry) > 2) { 2063 int err; 2064 2065 /* copy the target dentry's name */ 2066 dentry = d_alloc(new_dentry->d_parent, 2067 &new_dentry->d_name); 2068 if (!dentry) 2069 goto out; 2070 2071 /* silly-rename the existing target ... */ 2072 err = nfs_sillyrename(new_dir, new_dentry); 2073 if (err) 2074 goto out; 2075 2076 new_dentry = dentry; 2077 rehash = NULL; 2078 new_inode = NULL; 2079 } 2080 } 2081 2082 NFS_PROTO(old_inode)->return_delegation(old_inode); 2083 if (new_inode != NULL) 2084 NFS_PROTO(new_inode)->return_delegation(new_inode); 2085 2086 task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL); 2087 if (IS_ERR(task)) { 2088 error = PTR_ERR(task); 2089 goto out; 2090 } 2091 2092 error = rpc_wait_for_completion_task(task); 2093 if (error == 0) 2094 error = task->tk_status; 2095 rpc_put_task(task); 2096 nfs_mark_for_revalidate(old_inode); 2097 out: 2098 if (rehash) 2099 d_rehash(rehash); 2100 trace_nfs_rename_exit(old_dir, old_dentry, 2101 new_dir, new_dentry, error); 2102 if (!error) { 2103 if (new_inode != NULL) 2104 nfs_drop_nlink(new_inode); 2105 d_move(old_dentry, new_dentry); 2106 nfs_set_verifier(new_dentry, 2107 nfs_save_change_attribute(new_dir)); 2108 } else if (error == -ENOENT) 2109 nfs_dentry_handle_enoent(old_dentry); 2110 2111 /* new dentry created? */ 2112 if (dentry) 2113 dput(dentry); 2114 return error; 2115 } 2116 EXPORT_SYMBOL_GPL(nfs_rename); 2117 2118 static DEFINE_SPINLOCK(nfs_access_lru_lock); 2119 static LIST_HEAD(nfs_access_lru_list); 2120 static atomic_long_t nfs_access_nr_entries; 2121 2122 static unsigned long nfs_access_max_cachesize = ULONG_MAX; 2123 module_param(nfs_access_max_cachesize, ulong, 0644); 2124 MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length"); 2125 2126 static void nfs_access_free_entry(struct nfs_access_entry *entry) 2127 { 2128 put_rpccred(entry->cred); 2129 kfree_rcu(entry, rcu_head); 2130 smp_mb__before_atomic(); 2131 atomic_long_dec(&nfs_access_nr_entries); 2132 smp_mb__after_atomic(); 2133 } 2134 2135 static void nfs_access_free_list(struct list_head *head) 2136 { 2137 struct nfs_access_entry *cache; 2138 2139 while (!list_empty(head)) { 2140 cache = list_entry(head->next, struct nfs_access_entry, lru); 2141 list_del(&cache->lru); 2142 nfs_access_free_entry(cache); 2143 } 2144 } 2145 2146 static unsigned long 2147 nfs_do_access_cache_scan(unsigned int nr_to_scan) 2148 { 2149 LIST_HEAD(head); 2150 struct nfs_inode *nfsi, *next; 2151 struct nfs_access_entry *cache; 2152 long freed = 0; 2153 2154 spin_lock(&nfs_access_lru_lock); 2155 list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) { 2156 struct inode *inode; 2157 2158 if (nr_to_scan-- == 0) 2159 break; 2160 inode = &nfsi->vfs_inode; 2161 spin_lock(&inode->i_lock); 2162 if (list_empty(&nfsi->access_cache_entry_lru)) 2163 goto remove_lru_entry; 2164 cache = list_entry(nfsi->access_cache_entry_lru.next, 2165 struct nfs_access_entry, lru); 2166 list_move(&cache->lru, &head); 2167 rb_erase(&cache->rb_node, &nfsi->access_cache); 2168 freed++; 2169 if (!list_empty(&nfsi->access_cache_entry_lru)) 2170 list_move_tail(&nfsi->access_cache_inode_lru, 2171 &nfs_access_lru_list); 2172 else { 2173 remove_lru_entry: 2174 list_del_init(&nfsi->access_cache_inode_lru); 2175 smp_mb__before_atomic(); 2176 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); 2177 smp_mb__after_atomic(); 2178 } 2179 spin_unlock(&inode->i_lock); 2180 } 2181 spin_unlock(&nfs_access_lru_lock); 2182 nfs_access_free_list(&head); 2183 return freed; 2184 } 2185 2186 unsigned long 2187 nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc) 2188 { 2189 int nr_to_scan = sc->nr_to_scan; 2190 gfp_t gfp_mask = sc->gfp_mask; 2191 2192 if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL) 2193 return SHRINK_STOP; 2194 return nfs_do_access_cache_scan(nr_to_scan); 2195 } 2196 2197 2198 unsigned long 2199 nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc) 2200 { 2201 return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries)); 2202 } 2203 2204 static void 2205 nfs_access_cache_enforce_limit(void) 2206 { 2207 long nr_entries = atomic_long_read(&nfs_access_nr_entries); 2208 unsigned long diff; 2209 unsigned int nr_to_scan; 2210 2211 if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize) 2212 return; 2213 nr_to_scan = 100; 2214 diff = nr_entries - nfs_access_max_cachesize; 2215 if (diff < nr_to_scan) 2216 nr_to_scan = diff; 2217 nfs_do_access_cache_scan(nr_to_scan); 2218 } 2219 2220 static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head) 2221 { 2222 struct rb_root *root_node = &nfsi->access_cache; 2223 struct rb_node *n; 2224 struct nfs_access_entry *entry; 2225 2226 /* Unhook entries from the cache */ 2227 while ((n = rb_first(root_node)) != NULL) { 2228 entry = rb_entry(n, struct nfs_access_entry, rb_node); 2229 rb_erase(n, root_node); 2230 list_move(&entry->lru, head); 2231 } 2232 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; 2233 } 2234 2235 void nfs_access_zap_cache(struct inode *inode) 2236 { 2237 LIST_HEAD(head); 2238 2239 if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0) 2240 return; 2241 /* Remove from global LRU init */ 2242 spin_lock(&nfs_access_lru_lock); 2243 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2244 list_del_init(&NFS_I(inode)->access_cache_inode_lru); 2245 2246 spin_lock(&inode->i_lock); 2247 __nfs_access_zap_cache(NFS_I(inode), &head); 2248 spin_unlock(&inode->i_lock); 2249 spin_unlock(&nfs_access_lru_lock); 2250 nfs_access_free_list(&head); 2251 } 2252 EXPORT_SYMBOL_GPL(nfs_access_zap_cache); 2253 2254 static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred) 2255 { 2256 struct rb_node *n = NFS_I(inode)->access_cache.rb_node; 2257 struct nfs_access_entry *entry; 2258 2259 while (n != NULL) { 2260 entry = rb_entry(n, struct nfs_access_entry, rb_node); 2261 2262 if (cred < entry->cred) 2263 n = n->rb_left; 2264 else if (cred > entry->cred) 2265 n = n->rb_right; 2266 else 2267 return entry; 2268 } 2269 return NULL; 2270 } 2271 2272 static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res, bool may_block) 2273 { 2274 struct nfs_inode *nfsi = NFS_I(inode); 2275 struct nfs_access_entry *cache; 2276 bool retry = true; 2277 int err; 2278 2279 spin_lock(&inode->i_lock); 2280 for(;;) { 2281 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2282 goto out_zap; 2283 cache = nfs_access_search_rbtree(inode, cred); 2284 err = -ENOENT; 2285 if (cache == NULL) 2286 goto out; 2287 /* Found an entry, is our attribute cache valid? */ 2288 if (!nfs_attribute_cache_expired(inode) && 2289 !(nfsi->cache_validity & NFS_INO_INVALID_ATTR)) 2290 break; 2291 err = -ECHILD; 2292 if (!may_block) 2293 goto out; 2294 if (!retry) 2295 goto out_zap; 2296 spin_unlock(&inode->i_lock); 2297 err = __nfs_revalidate_inode(NFS_SERVER(inode), inode); 2298 if (err) 2299 return err; 2300 spin_lock(&inode->i_lock); 2301 retry = false; 2302 } 2303 res->jiffies = cache->jiffies; 2304 res->cred = cache->cred; 2305 res->mask = cache->mask; 2306 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru); 2307 err = 0; 2308 out: 2309 spin_unlock(&inode->i_lock); 2310 return err; 2311 out_zap: 2312 spin_unlock(&inode->i_lock); 2313 nfs_access_zap_cache(inode); 2314 return -ENOENT; 2315 } 2316 2317 static int nfs_access_get_cached_rcu(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) 2318 { 2319 /* Only check the most recently returned cache entry, 2320 * but do it without locking. 2321 */ 2322 struct nfs_inode *nfsi = NFS_I(inode); 2323 struct nfs_access_entry *cache; 2324 int err = -ECHILD; 2325 struct list_head *lh; 2326 2327 rcu_read_lock(); 2328 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 2329 goto out; 2330 lh = rcu_dereference(nfsi->access_cache_entry_lru.prev); 2331 cache = list_entry(lh, struct nfs_access_entry, lru); 2332 if (lh == &nfsi->access_cache_entry_lru || 2333 cred != cache->cred) 2334 cache = NULL; 2335 if (cache == NULL) 2336 goto out; 2337 err = nfs_revalidate_inode_rcu(NFS_SERVER(inode), inode); 2338 if (err) 2339 goto out; 2340 res->jiffies = cache->jiffies; 2341 res->cred = cache->cred; 2342 res->mask = cache->mask; 2343 out: 2344 rcu_read_unlock(); 2345 return err; 2346 } 2347 2348 static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) 2349 { 2350 struct nfs_inode *nfsi = NFS_I(inode); 2351 struct rb_root *root_node = &nfsi->access_cache; 2352 struct rb_node **p = &root_node->rb_node; 2353 struct rb_node *parent = NULL; 2354 struct nfs_access_entry *entry; 2355 2356 spin_lock(&inode->i_lock); 2357 while (*p != NULL) { 2358 parent = *p; 2359 entry = rb_entry(parent, struct nfs_access_entry, rb_node); 2360 2361 if (set->cred < entry->cred) 2362 p = &parent->rb_left; 2363 else if (set->cred > entry->cred) 2364 p = &parent->rb_right; 2365 else 2366 goto found; 2367 } 2368 rb_link_node(&set->rb_node, parent, p); 2369 rb_insert_color(&set->rb_node, root_node); 2370 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 2371 spin_unlock(&inode->i_lock); 2372 return; 2373 found: 2374 rb_replace_node(parent, &set->rb_node, root_node); 2375 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 2376 list_del(&entry->lru); 2377 spin_unlock(&inode->i_lock); 2378 nfs_access_free_entry(entry); 2379 } 2380 2381 void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) 2382 { 2383 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); 2384 if (cache == NULL) 2385 return; 2386 RB_CLEAR_NODE(&cache->rb_node); 2387 cache->jiffies = set->jiffies; 2388 cache->cred = get_rpccred(set->cred); 2389 cache->mask = set->mask; 2390 2391 /* The above field assignments must be visible 2392 * before this item appears on the lru. We cannot easily 2393 * use rcu_assign_pointer, so just force the memory barrier. 2394 */ 2395 smp_wmb(); 2396 nfs_access_add_rbtree(inode, cache); 2397 2398 /* Update accounting */ 2399 smp_mb__before_atomic(); 2400 atomic_long_inc(&nfs_access_nr_entries); 2401 smp_mb__after_atomic(); 2402 2403 /* Add inode to global LRU list */ 2404 if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) { 2405 spin_lock(&nfs_access_lru_lock); 2406 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) 2407 list_add_tail(&NFS_I(inode)->access_cache_inode_lru, 2408 &nfs_access_lru_list); 2409 spin_unlock(&nfs_access_lru_lock); 2410 } 2411 nfs_access_cache_enforce_limit(); 2412 } 2413 EXPORT_SYMBOL_GPL(nfs_access_add_cache); 2414 2415 void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result) 2416 { 2417 entry->mask = 0; 2418 if (access_result & NFS4_ACCESS_READ) 2419 entry->mask |= MAY_READ; 2420 if (access_result & 2421 (NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE)) 2422 entry->mask |= MAY_WRITE; 2423 if (access_result & (NFS4_ACCESS_LOOKUP|NFS4_ACCESS_EXECUTE)) 2424 entry->mask |= MAY_EXEC; 2425 } 2426 EXPORT_SYMBOL_GPL(nfs_access_set_mask); 2427 2428 static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) 2429 { 2430 struct nfs_access_entry cache; 2431 bool may_block = (mask & MAY_NOT_BLOCK) == 0; 2432 int status; 2433 2434 trace_nfs_access_enter(inode); 2435 2436 status = nfs_access_get_cached_rcu(inode, cred, &cache); 2437 if (status != 0) 2438 status = nfs_access_get_cached(inode, cred, &cache, may_block); 2439 if (status == 0) 2440 goto out_cached; 2441 2442 status = -ECHILD; 2443 if (!may_block) 2444 goto out; 2445 2446 /* Be clever: ask server to check for all possible rights */ 2447 cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ; 2448 cache.cred = cred; 2449 cache.jiffies = jiffies; 2450 status = NFS_PROTO(inode)->access(inode, &cache); 2451 if (status != 0) { 2452 if (status == -ESTALE) { 2453 nfs_zap_caches(inode); 2454 if (!S_ISDIR(inode->i_mode)) 2455 set_bit(NFS_INO_STALE, &NFS_I(inode)->flags); 2456 } 2457 goto out; 2458 } 2459 nfs_access_add_cache(inode, &cache); 2460 out_cached: 2461 if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0) 2462 status = -EACCES; 2463 out: 2464 trace_nfs_access_exit(inode, status); 2465 return status; 2466 } 2467 2468 static int nfs_open_permission_mask(int openflags) 2469 { 2470 int mask = 0; 2471 2472 if (openflags & __FMODE_EXEC) { 2473 /* ONLY check exec rights */ 2474 mask = MAY_EXEC; 2475 } else { 2476 if ((openflags & O_ACCMODE) != O_WRONLY) 2477 mask |= MAY_READ; 2478 if ((openflags & O_ACCMODE) != O_RDONLY) 2479 mask |= MAY_WRITE; 2480 } 2481 2482 return mask; 2483 } 2484 2485 int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags) 2486 { 2487 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); 2488 } 2489 EXPORT_SYMBOL_GPL(nfs_may_open); 2490 2491 static int nfs_execute_ok(struct inode *inode, int mask) 2492 { 2493 struct nfs_server *server = NFS_SERVER(inode); 2494 int ret; 2495 2496 if (mask & MAY_NOT_BLOCK) 2497 ret = nfs_revalidate_inode_rcu(server, inode); 2498 else 2499 ret = nfs_revalidate_inode(server, inode); 2500 if (ret == 0 && !execute_ok(inode)) 2501 ret = -EACCES; 2502 return ret; 2503 } 2504 2505 int nfs_permission(struct inode *inode, int mask) 2506 { 2507 struct rpc_cred *cred; 2508 int res = 0; 2509 2510 nfs_inc_stats(inode, NFSIOS_VFSACCESS); 2511 2512 if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) 2513 goto out; 2514 /* Is this sys_access() ? */ 2515 if (mask & (MAY_ACCESS | MAY_CHDIR)) 2516 goto force_lookup; 2517 2518 switch (inode->i_mode & S_IFMT) { 2519 case S_IFLNK: 2520 goto out; 2521 case S_IFREG: 2522 if ((mask & MAY_OPEN) && 2523 nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN)) 2524 return 0; 2525 break; 2526 case S_IFDIR: 2527 /* 2528 * Optimize away all write operations, since the server 2529 * will check permissions when we perform the op. 2530 */ 2531 if ((mask & MAY_WRITE) && !(mask & MAY_READ)) 2532 goto out; 2533 } 2534 2535 force_lookup: 2536 if (!NFS_PROTO(inode)->access) 2537 goto out_notsup; 2538 2539 /* Always try fast lookups first */ 2540 rcu_read_lock(); 2541 cred = rpc_lookup_cred_nonblock(); 2542 if (!IS_ERR(cred)) 2543 res = nfs_do_access(inode, cred, mask|MAY_NOT_BLOCK); 2544 else 2545 res = PTR_ERR(cred); 2546 rcu_read_unlock(); 2547 if (res == -ECHILD && !(mask & MAY_NOT_BLOCK)) { 2548 /* Fast lookup failed, try the slow way */ 2549 cred = rpc_lookup_cred(); 2550 if (!IS_ERR(cred)) { 2551 res = nfs_do_access(inode, cred, mask); 2552 put_rpccred(cred); 2553 } else 2554 res = PTR_ERR(cred); 2555 } 2556 out: 2557 if (!res && (mask & MAY_EXEC)) 2558 res = nfs_execute_ok(inode, mask); 2559 2560 dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n", 2561 inode->i_sb->s_id, inode->i_ino, mask, res); 2562 return res; 2563 out_notsup: 2564 if (mask & MAY_NOT_BLOCK) 2565 return -ECHILD; 2566 2567 res = nfs_revalidate_inode(NFS_SERVER(inode), inode); 2568 if (res == 0) 2569 res = generic_permission(inode, mask); 2570 goto out; 2571 } 2572 EXPORT_SYMBOL_GPL(nfs_permission); 2573 2574 /* 2575 * Local variables: 2576 * version-control: t 2577 * kept-new-versions: 5 2578 * End: 2579 */ 2580