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/smp_lock.h> 33 #include <linux/pagevec.h> 34 #include <linux/namei.h> 35 #include <linux/mount.h> 36 #include <linux/sched.h> 37 38 #include "nfs4_fs.h" 39 #include "delegation.h" 40 #include "iostat.h" 41 42 /* #define NFS_DEBUG_VERBOSE 1 */ 43 44 static int nfs_opendir(struct inode *, struct file *); 45 static int nfs_readdir(struct file *, void *, filldir_t); 46 static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *); 47 static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *); 48 static int nfs_mkdir(struct inode *, struct dentry *, int); 49 static int nfs_rmdir(struct inode *, struct dentry *); 50 static int nfs_unlink(struct inode *, struct dentry *); 51 static int nfs_symlink(struct inode *, struct dentry *, const char *); 52 static int nfs_link(struct dentry *, struct inode *, struct dentry *); 53 static int nfs_mknod(struct inode *, struct dentry *, int, dev_t); 54 static int nfs_rename(struct inode *, struct dentry *, 55 struct inode *, struct dentry *); 56 static int nfs_fsync_dir(struct file *, struct dentry *, int); 57 static loff_t nfs_llseek_dir(struct file *, loff_t, int); 58 59 const struct file_operations nfs_dir_operations = { 60 .llseek = nfs_llseek_dir, 61 .read = generic_read_dir, 62 .readdir = nfs_readdir, 63 .open = nfs_opendir, 64 .release = nfs_release, 65 .fsync = nfs_fsync_dir, 66 }; 67 68 const struct inode_operations nfs_dir_inode_operations = { 69 .create = nfs_create, 70 .lookup = nfs_lookup, 71 .link = nfs_link, 72 .unlink = nfs_unlink, 73 .symlink = nfs_symlink, 74 .mkdir = nfs_mkdir, 75 .rmdir = nfs_rmdir, 76 .mknod = nfs_mknod, 77 .rename = nfs_rename, 78 .permission = nfs_permission, 79 .getattr = nfs_getattr, 80 .setattr = nfs_setattr, 81 }; 82 83 #ifdef CONFIG_NFS_V3 84 const struct inode_operations nfs3_dir_inode_operations = { 85 .create = nfs_create, 86 .lookup = nfs_lookup, 87 .link = nfs_link, 88 .unlink = nfs_unlink, 89 .symlink = nfs_symlink, 90 .mkdir = nfs_mkdir, 91 .rmdir = nfs_rmdir, 92 .mknod = nfs_mknod, 93 .rename = nfs_rename, 94 .permission = nfs_permission, 95 .getattr = nfs_getattr, 96 .setattr = nfs_setattr, 97 .listxattr = nfs3_listxattr, 98 .getxattr = nfs3_getxattr, 99 .setxattr = nfs3_setxattr, 100 .removexattr = nfs3_removexattr, 101 }; 102 #endif /* CONFIG_NFS_V3 */ 103 104 #ifdef CONFIG_NFS_V4 105 106 static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *); 107 const struct inode_operations nfs4_dir_inode_operations = { 108 .create = nfs_create, 109 .lookup = nfs_atomic_lookup, 110 .link = nfs_link, 111 .unlink = nfs_unlink, 112 .symlink = nfs_symlink, 113 .mkdir = nfs_mkdir, 114 .rmdir = nfs_rmdir, 115 .mknod = nfs_mknod, 116 .rename = nfs_rename, 117 .permission = nfs_permission, 118 .getattr = nfs_getattr, 119 .setattr = nfs_setattr, 120 .getxattr = nfs4_getxattr, 121 .setxattr = nfs4_setxattr, 122 .listxattr = nfs4_listxattr, 123 }; 124 125 #endif /* CONFIG_NFS_V4 */ 126 127 /* 128 * Open file 129 */ 130 static int 131 nfs_opendir(struct inode *inode, struct file *filp) 132 { 133 int res; 134 135 dfprintk(VFS, "NFS: opendir(%s/%ld)\n", 136 inode->i_sb->s_id, inode->i_ino); 137 138 lock_kernel(); 139 /* Call generic open code in order to cache credentials */ 140 res = nfs_open(inode, filp); 141 unlock_kernel(); 142 return res; 143 } 144 145 typedef __be32 * (*decode_dirent_t)(__be32 *, struct nfs_entry *, int); 146 typedef struct { 147 struct file *file; 148 struct page *page; 149 unsigned long page_index; 150 __be32 *ptr; 151 u64 *dir_cookie; 152 loff_t current_index; 153 struct nfs_entry *entry; 154 decode_dirent_t decode; 155 int plus; 156 int error; 157 unsigned long timestamp; 158 int timestamp_valid; 159 } nfs_readdir_descriptor_t; 160 161 /* Now we cache directories properly, by stuffing the dirent 162 * data directly in the page cache. 163 * 164 * Inode invalidation due to refresh etc. takes care of 165 * _everything_, no sloppy entry flushing logic, no extraneous 166 * copying, network direct to page cache, the way it was meant 167 * to be. 168 * 169 * NOTE: Dirent information verification is done always by the 170 * page-in of the RPC reply, nowhere else, this simplies 171 * things substantially. 172 */ 173 static 174 int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page) 175 { 176 struct file *file = desc->file; 177 struct inode *inode = file->f_path.dentry->d_inode; 178 struct rpc_cred *cred = nfs_file_cred(file); 179 unsigned long timestamp; 180 int error; 181 182 dfprintk(DIRCACHE, "NFS: %s: reading cookie %Lu into page %lu\n", 183 __FUNCTION__, (long long)desc->entry->cookie, 184 page->index); 185 186 again: 187 timestamp = jiffies; 188 error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, desc->entry->cookie, page, 189 NFS_SERVER(inode)->dtsize, desc->plus); 190 if (error < 0) { 191 /* We requested READDIRPLUS, but the server doesn't grok it */ 192 if (error == -ENOTSUPP && desc->plus) { 193 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; 194 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode)); 195 desc->plus = 0; 196 goto again; 197 } 198 goto error; 199 } 200 desc->timestamp = timestamp; 201 desc->timestamp_valid = 1; 202 SetPageUptodate(page); 203 /* Ensure consistent page alignment of the data. 204 * Note: assumes we have exclusive access to this mapping either 205 * through inode->i_mutex or some other mechanism. 206 */ 207 if (page->index == 0 && invalidate_inode_pages2_range(inode->i_mapping, PAGE_CACHE_SIZE, -1) < 0) { 208 /* Should never happen */ 209 nfs_zap_mapping(inode, inode->i_mapping); 210 } 211 unlock_page(page); 212 return 0; 213 error: 214 unlock_page(page); 215 desc->error = error; 216 return -EIO; 217 } 218 219 static inline 220 int dir_decode(nfs_readdir_descriptor_t *desc) 221 { 222 __be32 *p = desc->ptr; 223 p = desc->decode(p, desc->entry, desc->plus); 224 if (IS_ERR(p)) 225 return PTR_ERR(p); 226 desc->ptr = p; 227 if (desc->timestamp_valid) 228 desc->entry->fattr->time_start = desc->timestamp; 229 else 230 desc->entry->fattr->valid &= ~NFS_ATTR_FATTR; 231 return 0; 232 } 233 234 static inline 235 void dir_page_release(nfs_readdir_descriptor_t *desc) 236 { 237 kunmap(desc->page); 238 page_cache_release(desc->page); 239 desc->page = NULL; 240 desc->ptr = NULL; 241 } 242 243 /* 244 * Given a pointer to a buffer that has already been filled by a call 245 * to readdir, find the next entry with cookie '*desc->dir_cookie'. 246 * 247 * If the end of the buffer has been reached, return -EAGAIN, if not, 248 * return the offset within the buffer of the next entry to be 249 * read. 250 */ 251 static inline 252 int find_dirent(nfs_readdir_descriptor_t *desc) 253 { 254 struct nfs_entry *entry = desc->entry; 255 int loop_count = 0, 256 status; 257 258 while((status = dir_decode(desc)) == 0) { 259 dfprintk(DIRCACHE, "NFS: %s: examining cookie %Lu\n", 260 __FUNCTION__, (unsigned long long)entry->cookie); 261 if (entry->prev_cookie == *desc->dir_cookie) 262 break; 263 if (loop_count++ > 200) { 264 loop_count = 0; 265 schedule(); 266 } 267 } 268 return status; 269 } 270 271 /* 272 * Given a pointer to a buffer that has already been filled by a call 273 * to readdir, find the entry at offset 'desc->file->f_pos'. 274 * 275 * If the end of the buffer has been reached, return -EAGAIN, if not, 276 * return the offset within the buffer of the next entry to be 277 * read. 278 */ 279 static inline 280 int find_dirent_index(nfs_readdir_descriptor_t *desc) 281 { 282 struct nfs_entry *entry = desc->entry; 283 int loop_count = 0, 284 status; 285 286 for(;;) { 287 status = dir_decode(desc); 288 if (status) 289 break; 290 291 dfprintk(DIRCACHE, "NFS: found cookie %Lu at index %Ld\n", 292 (unsigned long long)entry->cookie, desc->current_index); 293 294 if (desc->file->f_pos == desc->current_index) { 295 *desc->dir_cookie = entry->cookie; 296 break; 297 } 298 desc->current_index++; 299 if (loop_count++ > 200) { 300 loop_count = 0; 301 schedule(); 302 } 303 } 304 return status; 305 } 306 307 /* 308 * Find the given page, and call find_dirent() or find_dirent_index in 309 * order to try to return the next entry. 310 */ 311 static inline 312 int find_dirent_page(nfs_readdir_descriptor_t *desc) 313 { 314 struct inode *inode = desc->file->f_path.dentry->d_inode; 315 struct page *page; 316 int status; 317 318 dfprintk(DIRCACHE, "NFS: %s: searching page %ld for target %Lu\n", 319 __FUNCTION__, desc->page_index, 320 (long long) *desc->dir_cookie); 321 322 /* If we find the page in the page_cache, we cannot be sure 323 * how fresh the data is, so we will ignore readdir_plus attributes. 324 */ 325 desc->timestamp_valid = 0; 326 page = read_cache_page(inode->i_mapping, desc->page_index, 327 (filler_t *)nfs_readdir_filler, desc); 328 if (IS_ERR(page)) { 329 status = PTR_ERR(page); 330 goto out; 331 } 332 333 /* NOTE: Someone else may have changed the READDIRPLUS flag */ 334 desc->page = page; 335 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ 336 if (*desc->dir_cookie != 0) 337 status = find_dirent(desc); 338 else 339 status = find_dirent_index(desc); 340 if (status < 0) 341 dir_page_release(desc); 342 out: 343 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, status); 344 return status; 345 } 346 347 /* 348 * Recurse through the page cache pages, and return a 349 * filled nfs_entry structure of the next directory entry if possible. 350 * 351 * The target for the search is '*desc->dir_cookie' if non-0, 352 * 'desc->file->f_pos' otherwise 353 */ 354 static inline 355 int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) 356 { 357 int loop_count = 0; 358 int res; 359 360 /* Always search-by-index from the beginning of the cache */ 361 if (*desc->dir_cookie == 0) { 362 dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for offset %Ld\n", 363 (long long)desc->file->f_pos); 364 desc->page_index = 0; 365 desc->entry->cookie = desc->entry->prev_cookie = 0; 366 desc->entry->eof = 0; 367 desc->current_index = 0; 368 } else 369 dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", 370 (unsigned long long)*desc->dir_cookie); 371 372 for (;;) { 373 res = find_dirent_page(desc); 374 if (res != -EAGAIN) 375 break; 376 /* Align to beginning of next page */ 377 desc->page_index ++; 378 if (loop_count++ > 200) { 379 loop_count = 0; 380 schedule(); 381 } 382 } 383 384 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, res); 385 return res; 386 } 387 388 static inline unsigned int dt_type(struct inode *inode) 389 { 390 return (inode->i_mode >> 12) & 15; 391 } 392 393 static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc); 394 395 /* 396 * Once we've found the start of the dirent within a page: fill 'er up... 397 */ 398 static 399 int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent, 400 filldir_t filldir) 401 { 402 struct file *file = desc->file; 403 struct nfs_entry *entry = desc->entry; 404 struct dentry *dentry = NULL; 405 u64 fileid; 406 int loop_count = 0, 407 res; 408 409 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", 410 (unsigned long long)entry->cookie); 411 412 for(;;) { 413 unsigned d_type = DT_UNKNOWN; 414 /* Note: entry->prev_cookie contains the cookie for 415 * retrieving the current dirent on the server */ 416 fileid = entry->ino; 417 418 /* Get a dentry if we have one */ 419 if (dentry != NULL) 420 dput(dentry); 421 dentry = nfs_readdir_lookup(desc); 422 423 /* Use readdirplus info */ 424 if (dentry != NULL && dentry->d_inode != NULL) { 425 d_type = dt_type(dentry->d_inode); 426 fileid = NFS_FILEID(dentry->d_inode); 427 } 428 429 res = filldir(dirent, entry->name, entry->len, 430 file->f_pos, fileid, d_type); 431 if (res < 0) 432 break; 433 file->f_pos++; 434 *desc->dir_cookie = entry->cookie; 435 if (dir_decode(desc) != 0) { 436 desc->page_index ++; 437 break; 438 } 439 if (loop_count++ > 200) { 440 loop_count = 0; 441 schedule(); 442 } 443 } 444 dir_page_release(desc); 445 if (dentry != NULL) 446 dput(dentry); 447 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", 448 (unsigned long long)*desc->dir_cookie, res); 449 return res; 450 } 451 452 /* 453 * If we cannot find a cookie in our cache, we suspect that this is 454 * because it points to a deleted file, so we ask the server to return 455 * whatever it thinks is the next entry. We then feed this to filldir. 456 * If all goes well, we should then be able to find our way round the 457 * cache on the next call to readdir_search_pagecache(); 458 * 459 * NOTE: we cannot add the anonymous page to the pagecache because 460 * the data it contains might not be page aligned. Besides, 461 * we should already have a complete representation of the 462 * directory in the page cache by the time we get here. 463 */ 464 static inline 465 int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent, 466 filldir_t filldir) 467 { 468 struct file *file = desc->file; 469 struct inode *inode = file->f_path.dentry->d_inode; 470 struct rpc_cred *cred = nfs_file_cred(file); 471 struct page *page = NULL; 472 int status; 473 unsigned long timestamp; 474 475 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n", 476 (unsigned long long)*desc->dir_cookie); 477 478 page = alloc_page(GFP_HIGHUSER); 479 if (!page) { 480 status = -ENOMEM; 481 goto out; 482 } 483 timestamp = jiffies; 484 desc->error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, *desc->dir_cookie, 485 page, 486 NFS_SERVER(inode)->dtsize, 487 desc->plus); 488 desc->page = page; 489 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ 490 if (desc->error >= 0) { 491 desc->timestamp = timestamp; 492 desc->timestamp_valid = 1; 493 if ((status = dir_decode(desc)) == 0) 494 desc->entry->prev_cookie = *desc->dir_cookie; 495 } else 496 status = -EIO; 497 if (status < 0) 498 goto out_release; 499 500 status = nfs_do_filldir(desc, dirent, filldir); 501 502 /* Reset read descriptor so it searches the page cache from 503 * the start upon the next call to readdir_search_pagecache() */ 504 desc->page_index = 0; 505 desc->entry->cookie = desc->entry->prev_cookie = 0; 506 desc->entry->eof = 0; 507 out: 508 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", 509 __FUNCTION__, status); 510 return status; 511 out_release: 512 dir_page_release(desc); 513 goto out; 514 } 515 516 /* The file offset position represents the dirent entry number. A 517 last cookie cache takes care of the common case of reading the 518 whole directory. 519 */ 520 static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir) 521 { 522 struct dentry *dentry = filp->f_path.dentry; 523 struct inode *inode = dentry->d_inode; 524 nfs_readdir_descriptor_t my_desc, 525 *desc = &my_desc; 526 struct nfs_entry my_entry; 527 struct nfs_fh fh; 528 struct nfs_fattr fattr; 529 long res; 530 531 dfprintk(VFS, "NFS: readdir(%s/%s) starting at cookie %Lu\n", 532 dentry->d_parent->d_name.name, dentry->d_name.name, 533 (long long)filp->f_pos); 534 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); 535 536 lock_kernel(); 537 538 res = nfs_revalidate_mapping_nolock(inode, filp->f_mapping); 539 if (res < 0) { 540 unlock_kernel(); 541 return res; 542 } 543 544 /* 545 * filp->f_pos points to the dirent entry number. 546 * *desc->dir_cookie has the cookie for the next entry. We have 547 * to either find the entry with the appropriate number or 548 * revalidate the cookie. 549 */ 550 memset(desc, 0, sizeof(*desc)); 551 552 desc->file = filp; 553 desc->dir_cookie = &nfs_file_open_context(filp)->dir_cookie; 554 desc->decode = NFS_PROTO(inode)->decode_dirent; 555 desc->plus = NFS_USE_READDIRPLUS(inode); 556 557 my_entry.cookie = my_entry.prev_cookie = 0; 558 my_entry.eof = 0; 559 my_entry.fh = &fh; 560 my_entry.fattr = &fattr; 561 nfs_fattr_init(&fattr); 562 desc->entry = &my_entry; 563 564 while(!desc->entry->eof) { 565 res = readdir_search_pagecache(desc); 566 567 if (res == -EBADCOOKIE) { 568 /* This means either end of directory */ 569 if (*desc->dir_cookie && desc->entry->cookie != *desc->dir_cookie) { 570 /* Or that the server has 'lost' a cookie */ 571 res = uncached_readdir(desc, dirent, filldir); 572 if (res >= 0) 573 continue; 574 } 575 res = 0; 576 break; 577 } 578 if (res == -ETOOSMALL && desc->plus) { 579 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode)); 580 nfs_zap_caches(inode); 581 desc->plus = 0; 582 desc->entry->eof = 0; 583 continue; 584 } 585 if (res < 0) 586 break; 587 588 res = nfs_do_filldir(desc, dirent, filldir); 589 if (res < 0) { 590 res = 0; 591 break; 592 } 593 } 594 unlock_kernel(); 595 if (res > 0) 596 res = 0; 597 dfprintk(VFS, "NFS: readdir(%s/%s) returns %ld\n", 598 dentry->d_parent->d_name.name, dentry->d_name.name, 599 res); 600 return res; 601 } 602 603 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin) 604 { 605 mutex_lock(&filp->f_path.dentry->d_inode->i_mutex); 606 switch (origin) { 607 case 1: 608 offset += filp->f_pos; 609 case 0: 610 if (offset >= 0) 611 break; 612 default: 613 offset = -EINVAL; 614 goto out; 615 } 616 if (offset != filp->f_pos) { 617 filp->f_pos = offset; 618 nfs_file_open_context(filp)->dir_cookie = 0; 619 } 620 out: 621 mutex_unlock(&filp->f_path.dentry->d_inode->i_mutex); 622 return offset; 623 } 624 625 /* 626 * All directory operations under NFS are synchronous, so fsync() 627 * is a dummy operation. 628 */ 629 static int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync) 630 { 631 dfprintk(VFS, "NFS: fsync_dir(%s/%s) datasync %d\n", 632 dentry->d_parent->d_name.name, dentry->d_name.name, 633 datasync); 634 635 return 0; 636 } 637 638 /* 639 * A check for whether or not the parent directory has changed. 640 * In the case it has, we assume that the dentries are untrustworthy 641 * and may need to be looked up again. 642 */ 643 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry) 644 { 645 if (IS_ROOT(dentry)) 646 return 1; 647 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 648 return 0; 649 /* Revalidate nfsi->cache_change_attribute before we declare a match */ 650 if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) 651 return 0; 652 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 653 return 0; 654 return 1; 655 } 656 657 /* 658 * Return the intent data that applies to this particular path component 659 * 660 * Note that the current set of intents only apply to the very last 661 * component of the path. 662 * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT. 663 */ 664 static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask) 665 { 666 if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT)) 667 return 0; 668 return nd->flags & mask; 669 } 670 671 /* 672 * Use intent information to check whether or not we're going to do 673 * an O_EXCL create using this path component. 674 */ 675 static int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd) 676 { 677 if (NFS_PROTO(dir)->version == 2) 678 return 0; 679 if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0) 680 return 0; 681 return (nd->intent.open.flags & O_EXCL) != 0; 682 } 683 684 /* 685 * Inode and filehandle revalidation for lookups. 686 * 687 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, 688 * or if the intent information indicates that we're about to open this 689 * particular file and the "nocto" mount flag is not set. 690 * 691 */ 692 static inline 693 int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd) 694 { 695 struct nfs_server *server = NFS_SERVER(inode); 696 697 if (nd != NULL) { 698 /* VFS wants an on-the-wire revalidation */ 699 if (nd->flags & LOOKUP_REVAL) 700 goto out_force; 701 /* This is an open(2) */ 702 if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 && 703 !(server->flags & NFS_MOUNT_NOCTO) && 704 (S_ISREG(inode->i_mode) || 705 S_ISDIR(inode->i_mode))) 706 goto out_force; 707 } 708 return nfs_revalidate_inode(server, inode); 709 out_force: 710 return __nfs_revalidate_inode(server, inode); 711 } 712 713 /* 714 * We judge how long we want to trust negative 715 * dentries by looking at the parent inode mtime. 716 * 717 * If parent mtime has changed, we revalidate, else we wait for a 718 * period corresponding to the parent's attribute cache timeout value. 719 */ 720 static inline 721 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 722 struct nameidata *nd) 723 { 724 /* Don't revalidate a negative dentry if we're creating a new file */ 725 if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0) 726 return 0; 727 return !nfs_check_verifier(dir, dentry); 728 } 729 730 /* 731 * This is called every time the dcache has a lookup hit, 732 * and we should check whether we can really trust that 733 * lookup. 734 * 735 * NOTE! The hit can be a negative hit too, don't assume 736 * we have an inode! 737 * 738 * If the parent directory is seen to have changed, we throw out the 739 * cached dentry and do a new lookup. 740 */ 741 static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd) 742 { 743 struct inode *dir; 744 struct inode *inode; 745 struct dentry *parent; 746 int error; 747 struct nfs_fh fhandle; 748 struct nfs_fattr fattr; 749 750 parent = dget_parent(dentry); 751 lock_kernel(); 752 dir = parent->d_inode; 753 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); 754 inode = dentry->d_inode; 755 756 if (!inode) { 757 if (nfs_neg_need_reval(dir, dentry, nd)) 758 goto out_bad; 759 goto out_valid; 760 } 761 762 if (is_bad_inode(inode)) { 763 dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n", 764 __FUNCTION__, dentry->d_parent->d_name.name, 765 dentry->d_name.name); 766 goto out_bad; 767 } 768 769 /* Force a full look up iff the parent directory has changed */ 770 if (!nfs_is_exclusive_create(dir, nd) && nfs_check_verifier(dir, dentry)) { 771 if (nfs_lookup_verify_inode(inode, nd)) 772 goto out_zap_parent; 773 goto out_valid; 774 } 775 776 if (NFS_STALE(inode)) 777 goto out_bad; 778 779 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); 780 if (error) 781 goto out_bad; 782 if (nfs_compare_fh(NFS_FH(inode), &fhandle)) 783 goto out_bad; 784 if ((error = nfs_refresh_inode(inode, &fattr)) != 0) 785 goto out_bad; 786 787 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 788 out_valid: 789 unlock_kernel(); 790 dput(parent); 791 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n", 792 __FUNCTION__, dentry->d_parent->d_name.name, 793 dentry->d_name.name); 794 return 1; 795 out_zap_parent: 796 nfs_zap_caches(dir); 797 out_bad: 798 nfs_mark_for_revalidate(dir); 799 if (inode && S_ISDIR(inode->i_mode)) { 800 /* Purge readdir caches. */ 801 nfs_zap_caches(inode); 802 /* If we have submounts, don't unhash ! */ 803 if (have_submounts(dentry)) 804 goto out_valid; 805 shrink_dcache_parent(dentry); 806 } 807 d_drop(dentry); 808 unlock_kernel(); 809 dput(parent); 810 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n", 811 __FUNCTION__, dentry->d_parent->d_name.name, 812 dentry->d_name.name); 813 return 0; 814 } 815 816 /* 817 * This is called from dput() when d_count is going to 0. 818 */ 819 static int nfs_dentry_delete(struct dentry *dentry) 820 { 821 dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n", 822 dentry->d_parent->d_name.name, dentry->d_name.name, 823 dentry->d_flags); 824 825 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 826 /* Unhash it, so that ->d_iput() would be called */ 827 return 1; 828 } 829 if (!(dentry->d_sb->s_flags & MS_ACTIVE)) { 830 /* Unhash it, so that ancestors of killed async unlink 831 * files will be cleaned up during umount */ 832 return 1; 833 } 834 return 0; 835 836 } 837 838 /* 839 * Called when the dentry loses inode. 840 * We use it to clean up silly-renamed files. 841 */ 842 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) 843 { 844 nfs_inode_return_delegation(inode); 845 if (S_ISDIR(inode->i_mode)) 846 /* drop any readdir cache as it could easily be old */ 847 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA; 848 849 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 850 lock_kernel(); 851 drop_nlink(inode); 852 nfs_complete_unlink(dentry, inode); 853 unlock_kernel(); 854 } 855 iput(inode); 856 } 857 858 struct dentry_operations nfs_dentry_operations = { 859 .d_revalidate = nfs_lookup_revalidate, 860 .d_delete = nfs_dentry_delete, 861 .d_iput = nfs_dentry_iput, 862 }; 863 864 static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) 865 { 866 struct dentry *res; 867 struct inode *inode = NULL; 868 int error; 869 struct nfs_fh fhandle; 870 struct nfs_fattr fattr; 871 872 dfprintk(VFS, "NFS: lookup(%s/%s)\n", 873 dentry->d_parent->d_name.name, dentry->d_name.name); 874 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); 875 876 res = ERR_PTR(-ENAMETOOLONG); 877 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 878 goto out; 879 880 res = ERR_PTR(-ENOMEM); 881 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 882 883 lock_kernel(); 884 885 /* 886 * If we're doing an exclusive create, optimize away the lookup 887 * but don't hash the dentry. 888 */ 889 if (nfs_is_exclusive_create(dir, nd)) { 890 d_instantiate(dentry, NULL); 891 res = NULL; 892 goto out_unlock; 893 } 894 895 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); 896 if (error == -ENOENT) 897 goto no_entry; 898 if (error < 0) { 899 res = ERR_PTR(error); 900 goto out_unlock; 901 } 902 inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr); 903 res = (struct dentry *)inode; 904 if (IS_ERR(res)) 905 goto out_unlock; 906 907 no_entry: 908 res = d_materialise_unique(dentry, inode); 909 if (res != NULL) { 910 if (IS_ERR(res)) 911 goto out_unlock; 912 dentry = res; 913 } 914 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 915 out_unlock: 916 unlock_kernel(); 917 out: 918 return res; 919 } 920 921 #ifdef CONFIG_NFS_V4 922 static int nfs_open_revalidate(struct dentry *, struct nameidata *); 923 924 struct dentry_operations nfs4_dentry_operations = { 925 .d_revalidate = nfs_open_revalidate, 926 .d_delete = nfs_dentry_delete, 927 .d_iput = nfs_dentry_iput, 928 }; 929 930 /* 931 * Use intent information to determine whether we need to substitute 932 * the NFSv4-style stateful OPEN for the LOOKUP call 933 */ 934 static int is_atomic_open(struct inode *dir, struct nameidata *nd) 935 { 936 if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0) 937 return 0; 938 /* NFS does not (yet) have a stateful open for directories */ 939 if (nd->flags & LOOKUP_DIRECTORY) 940 return 0; 941 /* Are we trying to write to a read only partition? */ 942 if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE))) 943 return 0; 944 return 1; 945 } 946 947 static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) 948 { 949 struct dentry *res = NULL; 950 int error; 951 952 dfprintk(VFS, "NFS: atomic_lookup(%s/%ld), %s\n", 953 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 954 955 /* Check that we are indeed trying to open this file */ 956 if (!is_atomic_open(dir, nd)) 957 goto no_open; 958 959 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) { 960 res = ERR_PTR(-ENAMETOOLONG); 961 goto out; 962 } 963 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 964 965 /* Let vfs_create() deal with O_EXCL. Instantiate, but don't hash 966 * the dentry. */ 967 if (nd->intent.open.flags & O_EXCL) { 968 d_instantiate(dentry, NULL); 969 goto out; 970 } 971 972 /* Open the file on the server */ 973 lock_kernel(); 974 res = nfs4_atomic_open(dir, dentry, nd); 975 unlock_kernel(); 976 if (IS_ERR(res)) { 977 error = PTR_ERR(res); 978 switch (error) { 979 /* Make a negative dentry */ 980 case -ENOENT: 981 res = NULL; 982 goto out; 983 /* This turned out not to be a regular file */ 984 case -EISDIR: 985 case -ENOTDIR: 986 goto no_open; 987 case -ELOOP: 988 if (!(nd->intent.open.flags & O_NOFOLLOW)) 989 goto no_open; 990 /* case -EINVAL: */ 991 default: 992 goto out; 993 } 994 } else if (res != NULL) 995 dentry = res; 996 out: 997 return res; 998 no_open: 999 return nfs_lookup(dir, dentry, nd); 1000 } 1001 1002 static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd) 1003 { 1004 struct dentry *parent = NULL; 1005 struct inode *inode = dentry->d_inode; 1006 struct inode *dir; 1007 int openflags, ret = 0; 1008 1009 parent = dget_parent(dentry); 1010 dir = parent->d_inode; 1011 if (!is_atomic_open(dir, nd)) 1012 goto no_open; 1013 /* We can't create new files in nfs_open_revalidate(), so we 1014 * optimize away revalidation of negative dentries. 1015 */ 1016 if (inode == NULL) { 1017 if (!nfs_neg_need_reval(dir, dentry, nd)) 1018 ret = 1; 1019 goto out; 1020 } 1021 1022 /* NFS only supports OPEN on regular files */ 1023 if (!S_ISREG(inode->i_mode)) 1024 goto no_open; 1025 openflags = nd->intent.open.flags; 1026 /* We cannot do exclusive creation on a positive dentry */ 1027 if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) 1028 goto no_open; 1029 /* We can't create new files, or truncate existing ones here */ 1030 openflags &= ~(O_CREAT|O_TRUNC); 1031 1032 /* 1033 * Note: we're not holding inode->i_mutex and so may be racing with 1034 * operations that change the directory. We therefore save the 1035 * change attribute *before* we do the RPC call. 1036 */ 1037 lock_kernel(); 1038 ret = nfs4_open_revalidate(dir, dentry, openflags, nd); 1039 unlock_kernel(); 1040 out: 1041 dput(parent); 1042 if (!ret) 1043 d_drop(dentry); 1044 return ret; 1045 no_open: 1046 dput(parent); 1047 if (inode != NULL && nfs_have_delegation(inode, FMODE_READ)) 1048 return 1; 1049 return nfs_lookup_revalidate(dentry, nd); 1050 } 1051 #endif /* CONFIG_NFSV4 */ 1052 1053 static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc) 1054 { 1055 struct dentry *parent = desc->file->f_path.dentry; 1056 struct inode *dir = parent->d_inode; 1057 struct nfs_entry *entry = desc->entry; 1058 struct dentry *dentry, *alias; 1059 struct qstr name = { 1060 .name = entry->name, 1061 .len = entry->len, 1062 }; 1063 struct inode *inode; 1064 unsigned long verf = nfs_save_change_attribute(dir); 1065 1066 switch (name.len) { 1067 case 2: 1068 if (name.name[0] == '.' && name.name[1] == '.') 1069 return dget_parent(parent); 1070 break; 1071 case 1: 1072 if (name.name[0] == '.') 1073 return dget(parent); 1074 } 1075 1076 spin_lock(&dir->i_lock); 1077 if (NFS_I(dir)->cache_validity & NFS_INO_INVALID_DATA) { 1078 spin_unlock(&dir->i_lock); 1079 return NULL; 1080 } 1081 spin_unlock(&dir->i_lock); 1082 1083 name.hash = full_name_hash(name.name, name.len); 1084 dentry = d_lookup(parent, &name); 1085 if (dentry != NULL) { 1086 /* Is this a positive dentry that matches the readdir info? */ 1087 if (dentry->d_inode != NULL && 1088 (NFS_FILEID(dentry->d_inode) == entry->ino || 1089 d_mountpoint(dentry))) { 1090 if (!desc->plus || entry->fh->size == 0) 1091 return dentry; 1092 if (nfs_compare_fh(NFS_FH(dentry->d_inode), 1093 entry->fh) == 0) 1094 goto out_renew; 1095 } 1096 /* No, so d_drop to allow one to be created */ 1097 d_drop(dentry); 1098 dput(dentry); 1099 } 1100 if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR)) 1101 return NULL; 1102 if (name.len > NFS_SERVER(dir)->namelen) 1103 return NULL; 1104 /* Note: caller is already holding the dir->i_mutex! */ 1105 dentry = d_alloc(parent, &name); 1106 if (dentry == NULL) 1107 return NULL; 1108 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 1109 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); 1110 if (IS_ERR(inode)) { 1111 dput(dentry); 1112 return NULL; 1113 } 1114 1115 alias = d_materialise_unique(dentry, inode); 1116 if (alias != NULL) { 1117 dput(dentry); 1118 if (IS_ERR(alias)) 1119 return NULL; 1120 dentry = alias; 1121 } 1122 1123 out_renew: 1124 nfs_set_verifier(dentry, verf); 1125 return dentry; 1126 } 1127 1128 /* 1129 * Code common to create, mkdir, and mknod. 1130 */ 1131 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, 1132 struct nfs_fattr *fattr) 1133 { 1134 struct dentry *parent = dget_parent(dentry); 1135 struct inode *dir = parent->d_inode; 1136 struct inode *inode; 1137 int error = -EACCES; 1138 1139 d_drop(dentry); 1140 1141 /* We may have been initialized further down */ 1142 if (dentry->d_inode) 1143 goto out; 1144 if (fhandle->size == 0) { 1145 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); 1146 if (error) 1147 goto out_error; 1148 } 1149 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1150 if (!(fattr->valid & NFS_ATTR_FATTR)) { 1151 struct nfs_server *server = NFS_SB(dentry->d_sb); 1152 error = server->nfs_client->rpc_ops->getattr(server, fhandle, fattr); 1153 if (error < 0) 1154 goto out_error; 1155 } 1156 inode = nfs_fhget(dentry->d_sb, fhandle, fattr); 1157 error = PTR_ERR(inode); 1158 if (IS_ERR(inode)) 1159 goto out_error; 1160 d_add(dentry, inode); 1161 out: 1162 dput(parent); 1163 return 0; 1164 out_error: 1165 nfs_mark_for_revalidate(dir); 1166 dput(parent); 1167 return error; 1168 } 1169 1170 /* 1171 * Following a failed create operation, we drop the dentry rather 1172 * than retain a negative dentry. This avoids a problem in the event 1173 * that the operation succeeded on the server, but an error in the 1174 * reply path made it appear to have failed. 1175 */ 1176 static int nfs_create(struct inode *dir, struct dentry *dentry, int mode, 1177 struct nameidata *nd) 1178 { 1179 struct iattr attr; 1180 int error; 1181 int open_flags = 0; 1182 1183 dfprintk(VFS, "NFS: create(%s/%ld), %s\n", 1184 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1185 1186 attr.ia_mode = mode; 1187 attr.ia_valid = ATTR_MODE; 1188 1189 if ((nd->flags & LOOKUP_CREATE) != 0) 1190 open_flags = nd->intent.open.flags; 1191 1192 lock_kernel(); 1193 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd); 1194 if (error != 0) 1195 goto out_err; 1196 unlock_kernel(); 1197 return 0; 1198 out_err: 1199 unlock_kernel(); 1200 d_drop(dentry); 1201 return error; 1202 } 1203 1204 /* 1205 * See comments for nfs_proc_create regarding failed operations. 1206 */ 1207 static int 1208 nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev) 1209 { 1210 struct iattr attr; 1211 int status; 1212 1213 dfprintk(VFS, "NFS: mknod(%s/%ld), %s\n", 1214 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1215 1216 if (!new_valid_dev(rdev)) 1217 return -EINVAL; 1218 1219 attr.ia_mode = mode; 1220 attr.ia_valid = ATTR_MODE; 1221 1222 lock_kernel(); 1223 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); 1224 if (status != 0) 1225 goto out_err; 1226 unlock_kernel(); 1227 return 0; 1228 out_err: 1229 unlock_kernel(); 1230 d_drop(dentry); 1231 return status; 1232 } 1233 1234 /* 1235 * See comments for nfs_proc_create regarding failed operations. 1236 */ 1237 static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 1238 { 1239 struct iattr attr; 1240 int error; 1241 1242 dfprintk(VFS, "NFS: mkdir(%s/%ld), %s\n", 1243 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1244 1245 attr.ia_valid = ATTR_MODE; 1246 attr.ia_mode = mode | S_IFDIR; 1247 1248 lock_kernel(); 1249 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); 1250 if (error != 0) 1251 goto out_err; 1252 unlock_kernel(); 1253 return 0; 1254 out_err: 1255 d_drop(dentry); 1256 unlock_kernel(); 1257 return error; 1258 } 1259 1260 static int nfs_rmdir(struct inode *dir, struct dentry *dentry) 1261 { 1262 int error; 1263 1264 dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n", 1265 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1266 1267 lock_kernel(); 1268 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 1269 /* Ensure the VFS deletes this inode */ 1270 if (error == 0 && dentry->d_inode != NULL) 1271 clear_nlink(dentry->d_inode); 1272 unlock_kernel(); 1273 1274 return error; 1275 } 1276 1277 static int nfs_sillyrename(struct inode *dir, struct dentry *dentry) 1278 { 1279 static unsigned int sillycounter; 1280 const int fileidsize = sizeof(NFS_FILEID(dentry->d_inode))*2; 1281 const int countersize = sizeof(sillycounter)*2; 1282 const int slen = sizeof(".nfs")+fileidsize+countersize-1; 1283 char silly[slen+1]; 1284 struct qstr qsilly; 1285 struct dentry *sdentry; 1286 int error = -EIO; 1287 1288 dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n", 1289 dentry->d_parent->d_name.name, dentry->d_name.name, 1290 atomic_read(&dentry->d_count)); 1291 nfs_inc_stats(dir, NFSIOS_SILLYRENAME); 1292 1293 /* 1294 * We don't allow a dentry to be silly-renamed twice. 1295 */ 1296 error = -EBUSY; 1297 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 1298 goto out; 1299 1300 sprintf(silly, ".nfs%*.*Lx", 1301 fileidsize, fileidsize, 1302 (unsigned long long)NFS_FILEID(dentry->d_inode)); 1303 1304 /* Return delegation in anticipation of the rename */ 1305 nfs_inode_return_delegation(dentry->d_inode); 1306 1307 sdentry = NULL; 1308 do { 1309 char *suffix = silly + slen - countersize; 1310 1311 dput(sdentry); 1312 sillycounter++; 1313 sprintf(suffix, "%*.*x", countersize, countersize, sillycounter); 1314 1315 dfprintk(VFS, "NFS: trying to rename %s to %s\n", 1316 dentry->d_name.name, silly); 1317 1318 sdentry = lookup_one_len(silly, dentry->d_parent, slen); 1319 /* 1320 * N.B. Better to return EBUSY here ... it could be 1321 * dangerous to delete the file while it's in use. 1322 */ 1323 if (IS_ERR(sdentry)) 1324 goto out; 1325 } while(sdentry->d_inode != NULL); /* need negative lookup */ 1326 1327 qsilly.name = silly; 1328 qsilly.len = strlen(silly); 1329 if (dentry->d_inode) { 1330 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, 1331 dir, &qsilly); 1332 nfs_mark_for_revalidate(dentry->d_inode); 1333 } else 1334 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, 1335 dir, &qsilly); 1336 if (!error) { 1337 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1338 d_move(dentry, sdentry); 1339 error = nfs_async_unlink(dir, dentry); 1340 /* If we return 0 we don't unlink */ 1341 } 1342 dput(sdentry); 1343 out: 1344 return error; 1345 } 1346 1347 /* 1348 * Remove a file after making sure there are no pending writes, 1349 * and after checking that the file has only one user. 1350 * 1351 * We invalidate the attribute cache and free the inode prior to the operation 1352 * to avoid possible races if the server reuses the inode. 1353 */ 1354 static int nfs_safe_remove(struct dentry *dentry) 1355 { 1356 struct inode *dir = dentry->d_parent->d_inode; 1357 struct inode *inode = dentry->d_inode; 1358 int error = -EBUSY; 1359 1360 dfprintk(VFS, "NFS: safe_remove(%s/%s)\n", 1361 dentry->d_parent->d_name.name, dentry->d_name.name); 1362 1363 /* If the dentry was sillyrenamed, we simply call d_delete() */ 1364 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1365 error = 0; 1366 goto out; 1367 } 1368 1369 if (inode != NULL) { 1370 nfs_inode_return_delegation(inode); 1371 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1372 /* The VFS may want to delete this inode */ 1373 if (error == 0) 1374 drop_nlink(inode); 1375 nfs_mark_for_revalidate(inode); 1376 } else 1377 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1378 out: 1379 return error; 1380 } 1381 1382 /* We do silly rename. In case sillyrename() returns -EBUSY, the inode 1383 * belongs to an active ".nfs..." file and we return -EBUSY. 1384 * 1385 * If sillyrename() returns 0, we do nothing, otherwise we unlink. 1386 */ 1387 static int nfs_unlink(struct inode *dir, struct dentry *dentry) 1388 { 1389 int error; 1390 int need_rehash = 0; 1391 1392 dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id, 1393 dir->i_ino, dentry->d_name.name); 1394 1395 lock_kernel(); 1396 spin_lock(&dcache_lock); 1397 spin_lock(&dentry->d_lock); 1398 if (atomic_read(&dentry->d_count) > 1) { 1399 spin_unlock(&dentry->d_lock); 1400 spin_unlock(&dcache_lock); 1401 /* Start asynchronous writeout of the inode */ 1402 write_inode_now(dentry->d_inode, 0); 1403 error = nfs_sillyrename(dir, dentry); 1404 unlock_kernel(); 1405 return error; 1406 } 1407 if (!d_unhashed(dentry)) { 1408 __d_drop(dentry); 1409 need_rehash = 1; 1410 } 1411 spin_unlock(&dentry->d_lock); 1412 spin_unlock(&dcache_lock); 1413 error = nfs_safe_remove(dentry); 1414 if (!error) { 1415 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1416 } else if (need_rehash) 1417 d_rehash(dentry); 1418 unlock_kernel(); 1419 return error; 1420 } 1421 1422 /* 1423 * To create a symbolic link, most file systems instantiate a new inode, 1424 * add a page to it containing the path, then write it out to the disk 1425 * using prepare_write/commit_write. 1426 * 1427 * Unfortunately the NFS client can't create the in-core inode first 1428 * because it needs a file handle to create an in-core inode (see 1429 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the 1430 * symlink request has completed on the server. 1431 * 1432 * So instead we allocate a raw page, copy the symname into it, then do 1433 * the SYMLINK request with the page as the buffer. If it succeeds, we 1434 * now have a new file handle and can instantiate an in-core NFS inode 1435 * and move the raw page into its mapping. 1436 */ 1437 static int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) 1438 { 1439 struct pagevec lru_pvec; 1440 struct page *page; 1441 char *kaddr; 1442 struct iattr attr; 1443 unsigned int pathlen = strlen(symname); 1444 int error; 1445 1446 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id, 1447 dir->i_ino, dentry->d_name.name, symname); 1448 1449 if (pathlen > PAGE_SIZE) 1450 return -ENAMETOOLONG; 1451 1452 attr.ia_mode = S_IFLNK | S_IRWXUGO; 1453 attr.ia_valid = ATTR_MODE; 1454 1455 lock_kernel(); 1456 1457 page = alloc_page(GFP_HIGHUSER); 1458 if (!page) { 1459 unlock_kernel(); 1460 return -ENOMEM; 1461 } 1462 1463 kaddr = kmap_atomic(page, KM_USER0); 1464 memcpy(kaddr, symname, pathlen); 1465 if (pathlen < PAGE_SIZE) 1466 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); 1467 kunmap_atomic(kaddr, KM_USER0); 1468 1469 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr); 1470 if (error != 0) { 1471 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s) error %d\n", 1472 dir->i_sb->s_id, dir->i_ino, 1473 dentry->d_name.name, symname, error); 1474 d_drop(dentry); 1475 __free_page(page); 1476 unlock_kernel(); 1477 return error; 1478 } 1479 1480 /* 1481 * No big deal if we can't add this page to the page cache here. 1482 * READLINK will get the missing page from the server if needed. 1483 */ 1484 pagevec_init(&lru_pvec, 0); 1485 if (!add_to_page_cache(page, dentry->d_inode->i_mapping, 0, 1486 GFP_KERNEL)) { 1487 pagevec_add(&lru_pvec, page); 1488 pagevec_lru_add(&lru_pvec); 1489 SetPageUptodate(page); 1490 unlock_page(page); 1491 } else 1492 __free_page(page); 1493 1494 unlock_kernel(); 1495 return 0; 1496 } 1497 1498 static int 1499 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 1500 { 1501 struct inode *inode = old_dentry->d_inode; 1502 int error; 1503 1504 dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n", 1505 old_dentry->d_parent->d_name.name, old_dentry->d_name.name, 1506 dentry->d_parent->d_name.name, dentry->d_name.name); 1507 1508 lock_kernel(); 1509 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 1510 if (error == 0) { 1511 atomic_inc(&inode->i_count); 1512 d_instantiate(dentry, inode); 1513 } 1514 unlock_kernel(); 1515 return error; 1516 } 1517 1518 /* 1519 * RENAME 1520 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a 1521 * different file handle for the same inode after a rename (e.g. when 1522 * moving to a different directory). A fail-safe method to do so would 1523 * be to look up old_dir/old_name, create a link to new_dir/new_name and 1524 * rename the old file using the sillyrename stuff. This way, the original 1525 * file in old_dir will go away when the last process iput()s the inode. 1526 * 1527 * FIXED. 1528 * 1529 * It actually works quite well. One needs to have the possibility for 1530 * at least one ".nfs..." file in each directory the file ever gets 1531 * moved or linked to which happens automagically with the new 1532 * implementation that only depends on the dcache stuff instead of 1533 * using the inode layer 1534 * 1535 * Unfortunately, things are a little more complicated than indicated 1536 * above. For a cross-directory move, we want to make sure we can get 1537 * rid of the old inode after the operation. This means there must be 1538 * no pending writes (if it's a file), and the use count must be 1. 1539 * If these conditions are met, we can drop the dentries before doing 1540 * the rename. 1541 */ 1542 static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, 1543 struct inode *new_dir, struct dentry *new_dentry) 1544 { 1545 struct inode *old_inode = old_dentry->d_inode; 1546 struct inode *new_inode = new_dentry->d_inode; 1547 struct dentry *dentry = NULL, *rehash = NULL; 1548 int error = -EBUSY; 1549 1550 /* 1551 * To prevent any new references to the target during the rename, 1552 * we unhash the dentry and free the inode in advance. 1553 */ 1554 lock_kernel(); 1555 if (!d_unhashed(new_dentry)) { 1556 d_drop(new_dentry); 1557 rehash = new_dentry; 1558 } 1559 1560 dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n", 1561 old_dentry->d_parent->d_name.name, old_dentry->d_name.name, 1562 new_dentry->d_parent->d_name.name, new_dentry->d_name.name, 1563 atomic_read(&new_dentry->d_count)); 1564 1565 /* 1566 * First check whether the target is busy ... we can't 1567 * safely do _any_ rename if the target is in use. 1568 * 1569 * For files, make a copy of the dentry and then do a 1570 * silly-rename. If the silly-rename succeeds, the 1571 * copied dentry is hashed and becomes the new target. 1572 */ 1573 if (!new_inode) 1574 goto go_ahead; 1575 if (S_ISDIR(new_inode->i_mode)) { 1576 error = -EISDIR; 1577 if (!S_ISDIR(old_inode->i_mode)) 1578 goto out; 1579 } else if (atomic_read(&new_dentry->d_count) > 2) { 1580 int err; 1581 /* copy the target dentry's name */ 1582 dentry = d_alloc(new_dentry->d_parent, 1583 &new_dentry->d_name); 1584 if (!dentry) 1585 goto out; 1586 1587 /* silly-rename the existing target ... */ 1588 err = nfs_sillyrename(new_dir, new_dentry); 1589 if (!err) { 1590 new_dentry = rehash = dentry; 1591 new_inode = NULL; 1592 /* instantiate the replacement target */ 1593 d_instantiate(new_dentry, NULL); 1594 } else if (atomic_read(&new_dentry->d_count) > 1) 1595 /* dentry still busy? */ 1596 goto out; 1597 } else 1598 drop_nlink(new_inode); 1599 1600 go_ahead: 1601 /* 1602 * ... prune child dentries and writebacks if needed. 1603 */ 1604 if (atomic_read(&old_dentry->d_count) > 1) { 1605 if (S_ISREG(old_inode->i_mode)) 1606 nfs_wb_all(old_inode); 1607 shrink_dcache_parent(old_dentry); 1608 } 1609 nfs_inode_return_delegation(old_inode); 1610 1611 if (new_inode != NULL) { 1612 nfs_inode_return_delegation(new_inode); 1613 d_delete(new_dentry); 1614 } 1615 1616 error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name, 1617 new_dir, &new_dentry->d_name); 1618 nfs_mark_for_revalidate(old_inode); 1619 out: 1620 if (rehash) 1621 d_rehash(rehash); 1622 if (!error) { 1623 d_move(old_dentry, new_dentry); 1624 nfs_set_verifier(new_dentry, 1625 nfs_save_change_attribute(new_dir)); 1626 } 1627 1628 /* new dentry created? */ 1629 if (dentry) 1630 dput(dentry); 1631 unlock_kernel(); 1632 return error; 1633 } 1634 1635 static DEFINE_SPINLOCK(nfs_access_lru_lock); 1636 static LIST_HEAD(nfs_access_lru_list); 1637 static atomic_long_t nfs_access_nr_entries; 1638 1639 static void nfs_access_free_entry(struct nfs_access_entry *entry) 1640 { 1641 put_rpccred(entry->cred); 1642 kfree(entry); 1643 smp_mb__before_atomic_dec(); 1644 atomic_long_dec(&nfs_access_nr_entries); 1645 smp_mb__after_atomic_dec(); 1646 } 1647 1648 int nfs_access_cache_shrinker(int nr_to_scan, gfp_t gfp_mask) 1649 { 1650 LIST_HEAD(head); 1651 struct nfs_inode *nfsi; 1652 struct nfs_access_entry *cache; 1653 1654 restart: 1655 spin_lock(&nfs_access_lru_lock); 1656 list_for_each_entry(nfsi, &nfs_access_lru_list, access_cache_inode_lru) { 1657 struct inode *inode; 1658 1659 if (nr_to_scan-- == 0) 1660 break; 1661 inode = igrab(&nfsi->vfs_inode); 1662 if (inode == NULL) 1663 continue; 1664 spin_lock(&inode->i_lock); 1665 if (list_empty(&nfsi->access_cache_entry_lru)) 1666 goto remove_lru_entry; 1667 cache = list_entry(nfsi->access_cache_entry_lru.next, 1668 struct nfs_access_entry, lru); 1669 list_move(&cache->lru, &head); 1670 rb_erase(&cache->rb_node, &nfsi->access_cache); 1671 if (!list_empty(&nfsi->access_cache_entry_lru)) 1672 list_move_tail(&nfsi->access_cache_inode_lru, 1673 &nfs_access_lru_list); 1674 else { 1675 remove_lru_entry: 1676 list_del_init(&nfsi->access_cache_inode_lru); 1677 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); 1678 } 1679 spin_unlock(&inode->i_lock); 1680 spin_unlock(&nfs_access_lru_lock); 1681 iput(inode); 1682 goto restart; 1683 } 1684 spin_unlock(&nfs_access_lru_lock); 1685 while (!list_empty(&head)) { 1686 cache = list_entry(head.next, struct nfs_access_entry, lru); 1687 list_del(&cache->lru); 1688 nfs_access_free_entry(cache); 1689 } 1690 return (atomic_long_read(&nfs_access_nr_entries) / 100) * sysctl_vfs_cache_pressure; 1691 } 1692 1693 static void __nfs_access_zap_cache(struct inode *inode) 1694 { 1695 struct nfs_inode *nfsi = NFS_I(inode); 1696 struct rb_root *root_node = &nfsi->access_cache; 1697 struct rb_node *n, *dispose = NULL; 1698 struct nfs_access_entry *entry; 1699 1700 /* Unhook entries from the cache */ 1701 while ((n = rb_first(root_node)) != NULL) { 1702 entry = rb_entry(n, struct nfs_access_entry, rb_node); 1703 rb_erase(n, root_node); 1704 list_del(&entry->lru); 1705 n->rb_left = dispose; 1706 dispose = n; 1707 } 1708 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; 1709 spin_unlock(&inode->i_lock); 1710 1711 /* Now kill them all! */ 1712 while (dispose != NULL) { 1713 n = dispose; 1714 dispose = n->rb_left; 1715 nfs_access_free_entry(rb_entry(n, struct nfs_access_entry, rb_node)); 1716 } 1717 } 1718 1719 void nfs_access_zap_cache(struct inode *inode) 1720 { 1721 /* Remove from global LRU init */ 1722 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) { 1723 spin_lock(&nfs_access_lru_lock); 1724 list_del_init(&NFS_I(inode)->access_cache_inode_lru); 1725 spin_unlock(&nfs_access_lru_lock); 1726 } 1727 1728 spin_lock(&inode->i_lock); 1729 /* This will release the spinlock */ 1730 __nfs_access_zap_cache(inode); 1731 } 1732 1733 static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred) 1734 { 1735 struct rb_node *n = NFS_I(inode)->access_cache.rb_node; 1736 struct nfs_access_entry *entry; 1737 1738 while (n != NULL) { 1739 entry = rb_entry(n, struct nfs_access_entry, rb_node); 1740 1741 if (cred < entry->cred) 1742 n = n->rb_left; 1743 else if (cred > entry->cred) 1744 n = n->rb_right; 1745 else 1746 return entry; 1747 } 1748 return NULL; 1749 } 1750 1751 static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) 1752 { 1753 struct nfs_inode *nfsi = NFS_I(inode); 1754 struct nfs_access_entry *cache; 1755 int err = -ENOENT; 1756 1757 spin_lock(&inode->i_lock); 1758 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 1759 goto out_zap; 1760 cache = nfs_access_search_rbtree(inode, cred); 1761 if (cache == NULL) 1762 goto out; 1763 if (!time_in_range(jiffies, cache->jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))) 1764 goto out_stale; 1765 res->jiffies = cache->jiffies; 1766 res->cred = cache->cred; 1767 res->mask = cache->mask; 1768 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru); 1769 err = 0; 1770 out: 1771 spin_unlock(&inode->i_lock); 1772 return err; 1773 out_stale: 1774 rb_erase(&cache->rb_node, &nfsi->access_cache); 1775 list_del(&cache->lru); 1776 spin_unlock(&inode->i_lock); 1777 nfs_access_free_entry(cache); 1778 return -ENOENT; 1779 out_zap: 1780 /* This will release the spinlock */ 1781 __nfs_access_zap_cache(inode); 1782 return -ENOENT; 1783 } 1784 1785 static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) 1786 { 1787 struct nfs_inode *nfsi = NFS_I(inode); 1788 struct rb_root *root_node = &nfsi->access_cache; 1789 struct rb_node **p = &root_node->rb_node; 1790 struct rb_node *parent = NULL; 1791 struct nfs_access_entry *entry; 1792 1793 spin_lock(&inode->i_lock); 1794 while (*p != NULL) { 1795 parent = *p; 1796 entry = rb_entry(parent, struct nfs_access_entry, rb_node); 1797 1798 if (set->cred < entry->cred) 1799 p = &parent->rb_left; 1800 else if (set->cred > entry->cred) 1801 p = &parent->rb_right; 1802 else 1803 goto found; 1804 } 1805 rb_link_node(&set->rb_node, parent, p); 1806 rb_insert_color(&set->rb_node, root_node); 1807 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 1808 spin_unlock(&inode->i_lock); 1809 return; 1810 found: 1811 rb_replace_node(parent, &set->rb_node, root_node); 1812 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 1813 list_del(&entry->lru); 1814 spin_unlock(&inode->i_lock); 1815 nfs_access_free_entry(entry); 1816 } 1817 1818 static void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) 1819 { 1820 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); 1821 if (cache == NULL) 1822 return; 1823 RB_CLEAR_NODE(&cache->rb_node); 1824 cache->jiffies = set->jiffies; 1825 cache->cred = get_rpccred(set->cred); 1826 cache->mask = set->mask; 1827 1828 nfs_access_add_rbtree(inode, cache); 1829 1830 /* Update accounting */ 1831 smp_mb__before_atomic_inc(); 1832 atomic_long_inc(&nfs_access_nr_entries); 1833 smp_mb__after_atomic_inc(); 1834 1835 /* Add inode to global LRU list */ 1836 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) { 1837 spin_lock(&nfs_access_lru_lock); 1838 list_add_tail(&NFS_I(inode)->access_cache_inode_lru, &nfs_access_lru_list); 1839 spin_unlock(&nfs_access_lru_lock); 1840 } 1841 } 1842 1843 static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) 1844 { 1845 struct nfs_access_entry cache; 1846 int status; 1847 1848 status = nfs_access_get_cached(inode, cred, &cache); 1849 if (status == 0) 1850 goto out; 1851 1852 /* Be clever: ask server to check for all possible rights */ 1853 cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ; 1854 cache.cred = cred; 1855 cache.jiffies = jiffies; 1856 status = NFS_PROTO(inode)->access(inode, &cache); 1857 if (status != 0) 1858 return status; 1859 nfs_access_add_cache(inode, &cache); 1860 out: 1861 if ((cache.mask & mask) == mask) 1862 return 0; 1863 return -EACCES; 1864 } 1865 1866 static int nfs_open_permission_mask(int openflags) 1867 { 1868 int mask = 0; 1869 1870 if (openflags & FMODE_READ) 1871 mask |= MAY_READ; 1872 if (openflags & FMODE_WRITE) 1873 mask |= MAY_WRITE; 1874 if (openflags & FMODE_EXEC) 1875 mask |= MAY_EXEC; 1876 return mask; 1877 } 1878 1879 int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags) 1880 { 1881 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); 1882 } 1883 1884 int nfs_permission(struct inode *inode, int mask, struct nameidata *nd) 1885 { 1886 struct rpc_cred *cred; 1887 int res = 0; 1888 1889 nfs_inc_stats(inode, NFSIOS_VFSACCESS); 1890 1891 if (mask == 0) 1892 goto out; 1893 /* Is this sys_access() ? */ 1894 if (nd != NULL && (nd->flags & LOOKUP_ACCESS)) 1895 goto force_lookup; 1896 1897 switch (inode->i_mode & S_IFMT) { 1898 case S_IFLNK: 1899 goto out; 1900 case S_IFREG: 1901 /* NFSv4 has atomic_open... */ 1902 if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN) 1903 && nd != NULL 1904 && (nd->flags & LOOKUP_OPEN)) 1905 goto out; 1906 break; 1907 case S_IFDIR: 1908 /* 1909 * Optimize away all write operations, since the server 1910 * will check permissions when we perform the op. 1911 */ 1912 if ((mask & MAY_WRITE) && !(mask & MAY_READ)) 1913 goto out; 1914 } 1915 1916 force_lookup: 1917 lock_kernel(); 1918 1919 if (!NFS_PROTO(inode)->access) 1920 goto out_notsup; 1921 1922 cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0); 1923 if (!IS_ERR(cred)) { 1924 res = nfs_do_access(inode, cred, mask); 1925 put_rpccred(cred); 1926 } else 1927 res = PTR_ERR(cred); 1928 unlock_kernel(); 1929 out: 1930 dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n", 1931 inode->i_sb->s_id, inode->i_ino, mask, res); 1932 return res; 1933 out_notsup: 1934 res = nfs_revalidate_inode(NFS_SERVER(inode), inode); 1935 if (res == 0) 1936 res = generic_permission(inode, mask, NULL); 1937 unlock_kernel(); 1938 goto out; 1939 } 1940 1941 /* 1942 * Local variables: 1943 * version-control: t 1944 * kept-new-versions: 5 1945 * End: 1946 */ 1947