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/namei.h> 34 35 #include "nfs4_fs.h" 36 #include "delegation.h" 37 #include "iostat.h" 38 39 #define NFS_PARANOIA 1 40 /* #define NFS_DEBUG_VERBOSE 1 */ 41 42 static int nfs_opendir(struct inode *, struct file *); 43 static int nfs_readdir(struct file *, void *, filldir_t); 44 static struct dentry *nfs_lookup(struct inode *, struct dentry *, struct nameidata *); 45 static int nfs_create(struct inode *, struct dentry *, int, struct nameidata *); 46 static int nfs_mkdir(struct inode *, struct dentry *, int); 47 static int nfs_rmdir(struct inode *, struct dentry *); 48 static int nfs_unlink(struct inode *, struct dentry *); 49 static int nfs_symlink(struct inode *, struct dentry *, const char *); 50 static int nfs_link(struct dentry *, struct inode *, struct dentry *); 51 static int nfs_mknod(struct inode *, struct dentry *, int, dev_t); 52 static int nfs_rename(struct inode *, struct dentry *, 53 struct inode *, struct dentry *); 54 static int nfs_fsync_dir(struct file *, struct dentry *, int); 55 static loff_t nfs_llseek_dir(struct file *, loff_t, int); 56 57 struct file_operations nfs_dir_operations = { 58 .llseek = nfs_llseek_dir, 59 .read = generic_read_dir, 60 .readdir = nfs_readdir, 61 .open = nfs_opendir, 62 .release = nfs_release, 63 .fsync = nfs_fsync_dir, 64 }; 65 66 struct inode_operations nfs_dir_inode_operations = { 67 .create = nfs_create, 68 .lookup = nfs_lookup, 69 .link = nfs_link, 70 .unlink = nfs_unlink, 71 .symlink = nfs_symlink, 72 .mkdir = nfs_mkdir, 73 .rmdir = nfs_rmdir, 74 .mknod = nfs_mknod, 75 .rename = nfs_rename, 76 .permission = nfs_permission, 77 .getattr = nfs_getattr, 78 .setattr = nfs_setattr, 79 }; 80 81 #ifdef CONFIG_NFS_V3 82 struct inode_operations nfs3_dir_inode_operations = { 83 .create = nfs_create, 84 .lookup = nfs_lookup, 85 .link = nfs_link, 86 .unlink = nfs_unlink, 87 .symlink = nfs_symlink, 88 .mkdir = nfs_mkdir, 89 .rmdir = nfs_rmdir, 90 .mknod = nfs_mknod, 91 .rename = nfs_rename, 92 .permission = nfs_permission, 93 .getattr = nfs_getattr, 94 .setattr = nfs_setattr, 95 .listxattr = nfs3_listxattr, 96 .getxattr = nfs3_getxattr, 97 .setxattr = nfs3_setxattr, 98 .removexattr = nfs3_removexattr, 99 }; 100 #endif /* CONFIG_NFS_V3 */ 101 102 #ifdef CONFIG_NFS_V4 103 104 static struct dentry *nfs_atomic_lookup(struct inode *, struct dentry *, struct nameidata *); 105 struct inode_operations nfs4_dir_inode_operations = { 106 .create = nfs_create, 107 .lookup = nfs_atomic_lookup, 108 .link = nfs_link, 109 .unlink = nfs_unlink, 110 .symlink = nfs_symlink, 111 .mkdir = nfs_mkdir, 112 .rmdir = nfs_rmdir, 113 .mknod = nfs_mknod, 114 .rename = nfs_rename, 115 .permission = nfs_permission, 116 .getattr = nfs_getattr, 117 .setattr = nfs_setattr, 118 .getxattr = nfs4_getxattr, 119 .setxattr = nfs4_setxattr, 120 .listxattr = nfs4_listxattr, 121 }; 122 123 #endif /* CONFIG_NFS_V4 */ 124 125 /* 126 * Open file 127 */ 128 static int 129 nfs_opendir(struct inode *inode, struct file *filp) 130 { 131 int res = 0; 132 133 dfprintk(VFS, "NFS: opendir(%s/%ld)\n", 134 inode->i_sb->s_id, inode->i_ino); 135 136 lock_kernel(); 137 /* Call generic open code in order to cache credentials */ 138 if (!res) 139 res = nfs_open(inode, filp); 140 unlock_kernel(); 141 return res; 142 } 143 144 typedef u32 * (*decode_dirent_t)(u32 *, struct nfs_entry *, int); 145 typedef struct { 146 struct file *file; 147 struct page *page; 148 unsigned long page_index; 149 u32 *ptr; 150 u64 *dir_cookie; 151 loff_t current_index; 152 struct nfs_entry *entry; 153 decode_dirent_t decode; 154 int plus; 155 int error; 156 } nfs_readdir_descriptor_t; 157 158 /* Now we cache directories properly, by stuffing the dirent 159 * data directly in the page cache. 160 * 161 * Inode invalidation due to refresh etc. takes care of 162 * _everything_, no sloppy entry flushing logic, no extraneous 163 * copying, network direct to page cache, the way it was meant 164 * to be. 165 * 166 * NOTE: Dirent information verification is done always by the 167 * page-in of the RPC reply, nowhere else, this simplies 168 * things substantially. 169 */ 170 static 171 int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page) 172 { 173 struct file *file = desc->file; 174 struct inode *inode = file->f_dentry->d_inode; 175 struct rpc_cred *cred = nfs_file_cred(file); 176 unsigned long timestamp; 177 int error; 178 179 dfprintk(DIRCACHE, "NFS: %s: reading cookie %Lu into page %lu\n", 180 __FUNCTION__, (long long)desc->entry->cookie, 181 page->index); 182 183 again: 184 timestamp = jiffies; 185 error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, desc->entry->cookie, page, 186 NFS_SERVER(inode)->dtsize, desc->plus); 187 if (error < 0) { 188 /* We requested READDIRPLUS, but the server doesn't grok it */ 189 if (error == -ENOTSUPP && desc->plus) { 190 NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS; 191 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode)); 192 desc->plus = 0; 193 goto again; 194 } 195 goto error; 196 } 197 SetPageUptodate(page); 198 spin_lock(&inode->i_lock); 199 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME; 200 spin_unlock(&inode->i_lock); 201 /* Ensure consistent page alignment of the data. 202 * Note: assumes we have exclusive access to this mapping either 203 * through inode->i_mutex or some other mechanism. 204 */ 205 if (page->index == 0) 206 invalidate_inode_pages2_range(inode->i_mapping, PAGE_CACHE_SIZE, -1); 207 unlock_page(page); 208 return 0; 209 error: 210 SetPageError(page); 211 unlock_page(page); 212 nfs_zap_caches(inode); 213 desc->error = error; 214 return -EIO; 215 } 216 217 static inline 218 int dir_decode(nfs_readdir_descriptor_t *desc) 219 { 220 u32 *p = desc->ptr; 221 p = desc->decode(p, desc->entry, desc->plus); 222 if (IS_ERR(p)) 223 return PTR_ERR(p); 224 desc->ptr = p; 225 return 0; 226 } 227 228 static inline 229 void dir_page_release(nfs_readdir_descriptor_t *desc) 230 { 231 kunmap(desc->page); 232 page_cache_release(desc->page); 233 desc->page = NULL; 234 desc->ptr = NULL; 235 } 236 237 /* 238 * Given a pointer to a buffer that has already been filled by a call 239 * to readdir, find the next entry with cookie '*desc->dir_cookie'. 240 * 241 * If the end of the buffer has been reached, return -EAGAIN, if not, 242 * return the offset within the buffer of the next entry to be 243 * read. 244 */ 245 static inline 246 int find_dirent(nfs_readdir_descriptor_t *desc) 247 { 248 struct nfs_entry *entry = desc->entry; 249 int loop_count = 0, 250 status; 251 252 while((status = dir_decode(desc)) == 0) { 253 dfprintk(DIRCACHE, "NFS: %s: examining cookie %Lu\n", 254 __FUNCTION__, (unsigned long long)entry->cookie); 255 if (entry->prev_cookie == *desc->dir_cookie) 256 break; 257 if (loop_count++ > 200) { 258 loop_count = 0; 259 schedule(); 260 } 261 } 262 return status; 263 } 264 265 /* 266 * Given a pointer to a buffer that has already been filled by a call 267 * to readdir, find the entry at offset 'desc->file->f_pos'. 268 * 269 * If the end of the buffer has been reached, return -EAGAIN, if not, 270 * return the offset within the buffer of the next entry to be 271 * read. 272 */ 273 static inline 274 int find_dirent_index(nfs_readdir_descriptor_t *desc) 275 { 276 struct nfs_entry *entry = desc->entry; 277 int loop_count = 0, 278 status; 279 280 for(;;) { 281 status = dir_decode(desc); 282 if (status) 283 break; 284 285 dfprintk(DIRCACHE, "NFS: found cookie %Lu at index %Ld\n", 286 (unsigned long long)entry->cookie, desc->current_index); 287 288 if (desc->file->f_pos == desc->current_index) { 289 *desc->dir_cookie = entry->cookie; 290 break; 291 } 292 desc->current_index++; 293 if (loop_count++ > 200) { 294 loop_count = 0; 295 schedule(); 296 } 297 } 298 return status; 299 } 300 301 /* 302 * Find the given page, and call find_dirent() or find_dirent_index in 303 * order to try to return the next entry. 304 */ 305 static inline 306 int find_dirent_page(nfs_readdir_descriptor_t *desc) 307 { 308 struct inode *inode = desc->file->f_dentry->d_inode; 309 struct page *page; 310 int status; 311 312 dfprintk(DIRCACHE, "NFS: %s: searching page %ld for target %Lu\n", 313 __FUNCTION__, desc->page_index, 314 (long long) *desc->dir_cookie); 315 316 page = read_cache_page(inode->i_mapping, desc->page_index, 317 (filler_t *)nfs_readdir_filler, desc); 318 if (IS_ERR(page)) { 319 status = PTR_ERR(page); 320 goto out; 321 } 322 if (!PageUptodate(page)) 323 goto read_error; 324 325 /* NOTE: Someone else may have changed the READDIRPLUS flag */ 326 desc->page = page; 327 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ 328 if (*desc->dir_cookie != 0) 329 status = find_dirent(desc); 330 else 331 status = find_dirent_index(desc); 332 if (status < 0) 333 dir_page_release(desc); 334 out: 335 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, status); 336 return status; 337 read_error: 338 page_cache_release(page); 339 return -EIO; 340 } 341 342 /* 343 * Recurse through the page cache pages, and return a 344 * filled nfs_entry structure of the next directory entry if possible. 345 * 346 * The target for the search is '*desc->dir_cookie' if non-0, 347 * 'desc->file->f_pos' otherwise 348 */ 349 static inline 350 int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) 351 { 352 int loop_count = 0; 353 int res; 354 355 /* Always search-by-index from the beginning of the cache */ 356 if (*desc->dir_cookie == 0) { 357 dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for offset %Ld\n", 358 (long long)desc->file->f_pos); 359 desc->page_index = 0; 360 desc->entry->cookie = desc->entry->prev_cookie = 0; 361 desc->entry->eof = 0; 362 desc->current_index = 0; 363 } else 364 dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", 365 (unsigned long long)*desc->dir_cookie); 366 367 for (;;) { 368 res = find_dirent_page(desc); 369 if (res != -EAGAIN) 370 break; 371 /* Align to beginning of next page */ 372 desc->page_index ++; 373 if (loop_count++ > 200) { 374 loop_count = 0; 375 schedule(); 376 } 377 } 378 379 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, res); 380 return res; 381 } 382 383 static inline unsigned int dt_type(struct inode *inode) 384 { 385 return (inode->i_mode >> 12) & 15; 386 } 387 388 static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc); 389 390 /* 391 * Once we've found the start of the dirent within a page: fill 'er up... 392 */ 393 static 394 int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent, 395 filldir_t filldir) 396 { 397 struct file *file = desc->file; 398 struct nfs_entry *entry = desc->entry; 399 struct dentry *dentry = NULL; 400 unsigned long fileid; 401 int loop_count = 0, 402 res; 403 404 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", 405 (unsigned long long)entry->cookie); 406 407 for(;;) { 408 unsigned d_type = DT_UNKNOWN; 409 /* Note: entry->prev_cookie contains the cookie for 410 * retrieving the current dirent on the server */ 411 fileid = nfs_fileid_to_ino_t(entry->ino); 412 413 /* Get a dentry if we have one */ 414 if (dentry != NULL) 415 dput(dentry); 416 dentry = nfs_readdir_lookup(desc); 417 418 /* Use readdirplus info */ 419 if (dentry != NULL && dentry->d_inode != NULL) { 420 d_type = dt_type(dentry->d_inode); 421 fileid = dentry->d_inode->i_ino; 422 } 423 424 res = filldir(dirent, entry->name, entry->len, 425 file->f_pos, fileid, d_type); 426 if (res < 0) 427 break; 428 file->f_pos++; 429 *desc->dir_cookie = entry->cookie; 430 if (dir_decode(desc) != 0) { 431 desc->page_index ++; 432 break; 433 } 434 if (loop_count++ > 200) { 435 loop_count = 0; 436 schedule(); 437 } 438 } 439 dir_page_release(desc); 440 if (dentry != NULL) 441 dput(dentry); 442 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", 443 (unsigned long long)*desc->dir_cookie, res); 444 return res; 445 } 446 447 /* 448 * If we cannot find a cookie in our cache, we suspect that this is 449 * because it points to a deleted file, so we ask the server to return 450 * whatever it thinks is the next entry. We then feed this to filldir. 451 * If all goes well, we should then be able to find our way round the 452 * cache on the next call to readdir_search_pagecache(); 453 * 454 * NOTE: we cannot add the anonymous page to the pagecache because 455 * the data it contains might not be page aligned. Besides, 456 * we should already have a complete representation of the 457 * directory in the page cache by the time we get here. 458 */ 459 static inline 460 int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent, 461 filldir_t filldir) 462 { 463 struct file *file = desc->file; 464 struct inode *inode = file->f_dentry->d_inode; 465 struct rpc_cred *cred = nfs_file_cred(file); 466 struct page *page = NULL; 467 int status; 468 469 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n", 470 (unsigned long long)*desc->dir_cookie); 471 472 page = alloc_page(GFP_HIGHUSER); 473 if (!page) { 474 status = -ENOMEM; 475 goto out; 476 } 477 desc->error = NFS_PROTO(inode)->readdir(file->f_dentry, cred, *desc->dir_cookie, 478 page, 479 NFS_SERVER(inode)->dtsize, 480 desc->plus); 481 spin_lock(&inode->i_lock); 482 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME; 483 spin_unlock(&inode->i_lock); 484 desc->page = page; 485 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ 486 if (desc->error >= 0) { 487 if ((status = dir_decode(desc)) == 0) 488 desc->entry->prev_cookie = *desc->dir_cookie; 489 } else 490 status = -EIO; 491 if (status < 0) 492 goto out_release; 493 494 status = nfs_do_filldir(desc, dirent, filldir); 495 496 /* Reset read descriptor so it searches the page cache from 497 * the start upon the next call to readdir_search_pagecache() */ 498 desc->page_index = 0; 499 desc->entry->cookie = desc->entry->prev_cookie = 0; 500 desc->entry->eof = 0; 501 out: 502 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", 503 __FUNCTION__, status); 504 return status; 505 out_release: 506 dir_page_release(desc); 507 goto out; 508 } 509 510 /* The file offset position represents the dirent entry number. A 511 last cookie cache takes care of the common case of reading the 512 whole directory. 513 */ 514 static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir) 515 { 516 struct dentry *dentry = filp->f_dentry; 517 struct inode *inode = dentry->d_inode; 518 nfs_readdir_descriptor_t my_desc, 519 *desc = &my_desc; 520 struct nfs_entry my_entry; 521 struct nfs_fh fh; 522 struct nfs_fattr fattr; 523 long res; 524 525 dfprintk(VFS, "NFS: readdir(%s/%s) starting at cookie %Lu\n", 526 dentry->d_parent->d_name.name, dentry->d_name.name, 527 (long long)filp->f_pos); 528 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); 529 530 lock_kernel(); 531 532 res = nfs_revalidate_inode(NFS_SERVER(inode), inode); 533 if (res < 0) { 534 unlock_kernel(); 535 return res; 536 } 537 538 /* 539 * filp->f_pos points to the dirent entry number. 540 * *desc->dir_cookie has the cookie for the next entry. We have 541 * to either find the entry with the appropriate number or 542 * revalidate the cookie. 543 */ 544 memset(desc, 0, sizeof(*desc)); 545 546 desc->file = filp; 547 desc->dir_cookie = &((struct nfs_open_context *)filp->private_data)->dir_cookie; 548 desc->decode = NFS_PROTO(inode)->decode_dirent; 549 desc->plus = NFS_USE_READDIRPLUS(inode); 550 551 my_entry.cookie = my_entry.prev_cookie = 0; 552 my_entry.eof = 0; 553 my_entry.fh = &fh; 554 my_entry.fattr = &fattr; 555 nfs_fattr_init(&fattr); 556 desc->entry = &my_entry; 557 558 while(!desc->entry->eof) { 559 res = readdir_search_pagecache(desc); 560 561 if (res == -EBADCOOKIE) { 562 /* This means either end of directory */ 563 if (*desc->dir_cookie && desc->entry->cookie != *desc->dir_cookie) { 564 /* Or that the server has 'lost' a cookie */ 565 res = uncached_readdir(desc, dirent, filldir); 566 if (res >= 0) 567 continue; 568 } 569 res = 0; 570 break; 571 } 572 if (res == -ETOOSMALL && desc->plus) { 573 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode)); 574 nfs_zap_caches(inode); 575 desc->plus = 0; 576 desc->entry->eof = 0; 577 continue; 578 } 579 if (res < 0) 580 break; 581 582 res = nfs_do_filldir(desc, dirent, filldir); 583 if (res < 0) { 584 res = 0; 585 break; 586 } 587 } 588 unlock_kernel(); 589 if (res > 0) 590 res = 0; 591 dfprintk(VFS, "NFS: readdir(%s/%s) returns %ld\n", 592 dentry->d_parent->d_name.name, dentry->d_name.name, 593 res); 594 return res; 595 } 596 597 loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin) 598 { 599 mutex_lock(&filp->f_dentry->d_inode->i_mutex); 600 switch (origin) { 601 case 1: 602 offset += filp->f_pos; 603 case 0: 604 if (offset >= 0) 605 break; 606 default: 607 offset = -EINVAL; 608 goto out; 609 } 610 if (offset != filp->f_pos) { 611 filp->f_pos = offset; 612 ((struct nfs_open_context *)filp->private_data)->dir_cookie = 0; 613 } 614 out: 615 mutex_unlock(&filp->f_dentry->d_inode->i_mutex); 616 return offset; 617 } 618 619 /* 620 * All directory operations under NFS are synchronous, so fsync() 621 * is a dummy operation. 622 */ 623 int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync) 624 { 625 dfprintk(VFS, "NFS: fsync_dir(%s/%s) datasync %d\n", 626 dentry->d_parent->d_name.name, dentry->d_name.name, 627 datasync); 628 629 return 0; 630 } 631 632 /* 633 * A check for whether or not the parent directory has changed. 634 * In the case it has, we assume that the dentries are untrustworthy 635 * and may need to be looked up again. 636 */ 637 static inline int nfs_check_verifier(struct inode *dir, struct dentry *dentry) 638 { 639 if (IS_ROOT(dentry)) 640 return 1; 641 if ((NFS_I(dir)->cache_validity & NFS_INO_INVALID_ATTR) != 0 642 || nfs_attribute_timeout(dir)) 643 return 0; 644 return nfs_verify_change_attribute(dir, (unsigned long)dentry->d_fsdata); 645 } 646 647 static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf) 648 { 649 dentry->d_fsdata = (void *)verf; 650 } 651 652 /* 653 * Whenever an NFS operation succeeds, we know that the dentry 654 * is valid, so we update the revalidation timestamp. 655 */ 656 static inline void nfs_renew_times(struct dentry * dentry) 657 { 658 dentry->d_time = jiffies; 659 } 660 661 /* 662 * Return the intent data that applies to this particular path component 663 * 664 * Note that the current set of intents only apply to the very last 665 * component of the path. 666 * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT. 667 */ 668 static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask) 669 { 670 if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT)) 671 return 0; 672 return nd->flags & mask; 673 } 674 675 /* 676 * Inode and filehandle revalidation for lookups. 677 * 678 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, 679 * or if the intent information indicates that we're about to open this 680 * particular file and the "nocto" mount flag is not set. 681 * 682 */ 683 static inline 684 int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd) 685 { 686 struct nfs_server *server = NFS_SERVER(inode); 687 688 if (nd != NULL) { 689 /* VFS wants an on-the-wire revalidation */ 690 if (nd->flags & LOOKUP_REVAL) 691 goto out_force; 692 /* This is an open(2) */ 693 if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 && 694 !(server->flags & NFS_MOUNT_NOCTO)) 695 goto out_force; 696 } 697 return nfs_revalidate_inode(server, inode); 698 out_force: 699 return __nfs_revalidate_inode(server, inode); 700 } 701 702 /* 703 * We judge how long we want to trust negative 704 * dentries by looking at the parent inode mtime. 705 * 706 * If parent mtime has changed, we revalidate, else we wait for a 707 * period corresponding to the parent's attribute cache timeout value. 708 */ 709 static inline 710 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 711 struct nameidata *nd) 712 { 713 /* Don't revalidate a negative dentry if we're creating a new file */ 714 if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0) 715 return 0; 716 return !nfs_check_verifier(dir, dentry); 717 } 718 719 /* 720 * This is called every time the dcache has a lookup hit, 721 * and we should check whether we can really trust that 722 * lookup. 723 * 724 * NOTE! The hit can be a negative hit too, don't assume 725 * we have an inode! 726 * 727 * If the parent directory is seen to have changed, we throw out the 728 * cached dentry and do a new lookup. 729 */ 730 static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd) 731 { 732 struct inode *dir; 733 struct inode *inode; 734 struct dentry *parent; 735 int error; 736 struct nfs_fh fhandle; 737 struct nfs_fattr fattr; 738 unsigned long verifier; 739 740 parent = dget_parent(dentry); 741 lock_kernel(); 742 dir = parent->d_inode; 743 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); 744 inode = dentry->d_inode; 745 746 if (!inode) { 747 if (nfs_neg_need_reval(dir, dentry, nd)) 748 goto out_bad; 749 goto out_valid; 750 } 751 752 if (is_bad_inode(inode)) { 753 dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n", 754 __FUNCTION__, dentry->d_parent->d_name.name, 755 dentry->d_name.name); 756 goto out_bad; 757 } 758 759 /* Revalidate parent directory attribute cache */ 760 if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) 761 goto out_zap_parent; 762 763 /* Force a full look up iff the parent directory has changed */ 764 if (nfs_check_verifier(dir, dentry)) { 765 if (nfs_lookup_verify_inode(inode, nd)) 766 goto out_zap_parent; 767 goto out_valid; 768 } 769 770 if (NFS_STALE(inode)) 771 goto out_bad; 772 773 verifier = nfs_save_change_attribute(dir); 774 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); 775 if (error) 776 goto out_bad; 777 if (nfs_compare_fh(NFS_FH(inode), &fhandle)) 778 goto out_bad; 779 if ((error = nfs_refresh_inode(inode, &fattr)) != 0) 780 goto out_bad; 781 782 nfs_renew_times(dentry); 783 nfs_set_verifier(dentry, verifier); 784 out_valid: 785 unlock_kernel(); 786 dput(parent); 787 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n", 788 __FUNCTION__, dentry->d_parent->d_name.name, 789 dentry->d_name.name); 790 return 1; 791 out_zap_parent: 792 nfs_zap_caches(dir); 793 out_bad: 794 NFS_CACHEINV(dir); 795 if (inode && S_ISDIR(inode->i_mode)) { 796 /* Purge readdir caches. */ 797 nfs_zap_caches(inode); 798 /* If we have submounts, don't unhash ! */ 799 if (have_submounts(dentry)) 800 goto out_valid; 801 shrink_dcache_parent(dentry); 802 } 803 d_drop(dentry); 804 unlock_kernel(); 805 dput(parent); 806 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n", 807 __FUNCTION__, dentry->d_parent->d_name.name, 808 dentry->d_name.name); 809 return 0; 810 } 811 812 /* 813 * This is called from dput() when d_count is going to 0. 814 */ 815 static int nfs_dentry_delete(struct dentry *dentry) 816 { 817 dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n", 818 dentry->d_parent->d_name.name, dentry->d_name.name, 819 dentry->d_flags); 820 821 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 822 /* Unhash it, so that ->d_iput() would be called */ 823 return 1; 824 } 825 if (!(dentry->d_sb->s_flags & MS_ACTIVE)) { 826 /* Unhash it, so that ancestors of killed async unlink 827 * files will be cleaned up during umount */ 828 return 1; 829 } 830 return 0; 831 832 } 833 834 /* 835 * Called when the dentry loses inode. 836 * We use it to clean up silly-renamed files. 837 */ 838 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) 839 { 840 nfs_inode_return_delegation(inode); 841 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 842 lock_kernel(); 843 inode->i_nlink--; 844 nfs_complete_unlink(dentry); 845 unlock_kernel(); 846 } 847 /* When creating a negative dentry, we want to renew d_time */ 848 nfs_renew_times(dentry); 849 iput(inode); 850 } 851 852 struct dentry_operations nfs_dentry_operations = { 853 .d_revalidate = nfs_lookup_revalidate, 854 .d_delete = nfs_dentry_delete, 855 .d_iput = nfs_dentry_iput, 856 }; 857 858 /* 859 * Use intent information to check whether or not we're going to do 860 * an O_EXCL create using this path component. 861 */ 862 static inline 863 int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd) 864 { 865 if (NFS_PROTO(dir)->version == 2) 866 return 0; 867 if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_CREATE) == 0) 868 return 0; 869 return (nd->intent.open.flags & O_EXCL) != 0; 870 } 871 872 static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) 873 { 874 struct dentry *res; 875 struct inode *inode = NULL; 876 int error; 877 struct nfs_fh fhandle; 878 struct nfs_fattr fattr; 879 880 dfprintk(VFS, "NFS: lookup(%s/%s)\n", 881 dentry->d_parent->d_name.name, dentry->d_name.name); 882 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); 883 884 res = ERR_PTR(-ENAMETOOLONG); 885 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 886 goto out; 887 888 res = ERR_PTR(-ENOMEM); 889 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 890 891 lock_kernel(); 892 893 /* If we're doing an exclusive create, optimize away the lookup */ 894 if (nfs_is_exclusive_create(dir, nd)) 895 goto no_entry; 896 897 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); 898 if (error == -ENOENT) 899 goto no_entry; 900 if (error < 0) { 901 res = ERR_PTR(error); 902 goto out_unlock; 903 } 904 res = ERR_PTR(-EACCES); 905 inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr); 906 if (!inode) 907 goto out_unlock; 908 no_entry: 909 res = d_add_unique(dentry, inode); 910 if (res != NULL) 911 dentry = res; 912 nfs_renew_times(dentry); 913 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 914 out_unlock: 915 unlock_kernel(); 916 out: 917 return res; 918 } 919 920 #ifdef CONFIG_NFS_V4 921 static int nfs_open_revalidate(struct dentry *, struct nameidata *); 922 923 struct dentry_operations nfs4_dentry_operations = { 924 .d_revalidate = nfs_open_revalidate, 925 .d_delete = nfs_dentry_delete, 926 .d_iput = nfs_dentry_iput, 927 }; 928 929 /* 930 * Use intent information to determine whether we need to substitute 931 * the NFSv4-style stateful OPEN for the LOOKUP call 932 */ 933 static int is_atomic_open(struct inode *dir, struct nameidata *nd) 934 { 935 if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0) 936 return 0; 937 /* NFS does not (yet) have a stateful open for directories */ 938 if (nd->flags & LOOKUP_DIRECTORY) 939 return 0; 940 /* Are we trying to write to a read only partition? */ 941 if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE))) 942 return 0; 943 return 1; 944 } 945 946 static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) 947 { 948 struct dentry *res = NULL; 949 int error; 950 951 dfprintk(VFS, "NFS: atomic_lookup(%s/%ld), %s\n", 952 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 953 954 /* Check that we are indeed trying to open this file */ 955 if (!is_atomic_open(dir, nd)) 956 goto no_open; 957 958 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) { 959 res = ERR_PTR(-ENAMETOOLONG); 960 goto out; 961 } 962 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 963 964 /* Let vfs_create() deal with O_EXCL */ 965 if (nd->intent.open.flags & O_EXCL) { 966 d_add(dentry, NULL); 967 goto out; 968 } 969 970 /* Open the file on the server */ 971 lock_kernel(); 972 /* Revalidate parent directory attribute cache */ 973 error = nfs_revalidate_inode(NFS_SERVER(dir), dir); 974 if (error < 0) { 975 res = ERR_PTR(error); 976 unlock_kernel(); 977 goto out; 978 } 979 980 if (nd->intent.open.flags & O_CREAT) { 981 nfs_begin_data_update(dir); 982 res = nfs4_atomic_open(dir, dentry, nd); 983 nfs_end_data_update(dir); 984 } else 985 res = nfs4_atomic_open(dir, dentry, nd); 986 unlock_kernel(); 987 if (IS_ERR(res)) { 988 error = PTR_ERR(res); 989 switch (error) { 990 /* Make a negative dentry */ 991 case -ENOENT: 992 res = NULL; 993 goto out; 994 /* This turned out not to be a regular file */ 995 case -EISDIR: 996 case -ENOTDIR: 997 goto no_open; 998 case -ELOOP: 999 if (!(nd->intent.open.flags & O_NOFOLLOW)) 1000 goto no_open; 1001 /* case -EINVAL: */ 1002 default: 1003 goto out; 1004 } 1005 } else if (res != NULL) 1006 dentry = res; 1007 nfs_renew_times(dentry); 1008 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1009 out: 1010 return res; 1011 no_open: 1012 return nfs_lookup(dir, dentry, nd); 1013 } 1014 1015 static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd) 1016 { 1017 struct dentry *parent = NULL; 1018 struct inode *inode = dentry->d_inode; 1019 struct inode *dir; 1020 unsigned long verifier; 1021 int openflags, ret = 0; 1022 1023 parent = dget_parent(dentry); 1024 dir = parent->d_inode; 1025 if (!is_atomic_open(dir, nd)) 1026 goto no_open; 1027 /* We can't create new files in nfs_open_revalidate(), so we 1028 * optimize away revalidation of negative dentries. 1029 */ 1030 if (inode == NULL) 1031 goto out; 1032 /* NFS only supports OPEN on regular files */ 1033 if (!S_ISREG(inode->i_mode)) 1034 goto no_open; 1035 openflags = nd->intent.open.flags; 1036 /* We cannot do exclusive creation on a positive dentry */ 1037 if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) 1038 goto no_open; 1039 /* We can't create new files, or truncate existing ones here */ 1040 openflags &= ~(O_CREAT|O_TRUNC); 1041 1042 /* 1043 * Note: we're not holding inode->i_mutex and so may be racing with 1044 * operations that change the directory. We therefore save the 1045 * change attribute *before* we do the RPC call. 1046 */ 1047 lock_kernel(); 1048 verifier = nfs_save_change_attribute(dir); 1049 ret = nfs4_open_revalidate(dir, dentry, openflags, nd); 1050 if (!ret) 1051 nfs_set_verifier(dentry, verifier); 1052 unlock_kernel(); 1053 out: 1054 dput(parent); 1055 if (!ret) 1056 d_drop(dentry); 1057 return ret; 1058 no_open: 1059 dput(parent); 1060 if (inode != NULL && nfs_have_delegation(inode, FMODE_READ)) 1061 return 1; 1062 return nfs_lookup_revalidate(dentry, nd); 1063 } 1064 #endif /* CONFIG_NFSV4 */ 1065 1066 static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc) 1067 { 1068 struct dentry *parent = desc->file->f_dentry; 1069 struct inode *dir = parent->d_inode; 1070 struct nfs_entry *entry = desc->entry; 1071 struct dentry *dentry, *alias; 1072 struct qstr name = { 1073 .name = entry->name, 1074 .len = entry->len, 1075 }; 1076 struct inode *inode; 1077 1078 switch (name.len) { 1079 case 2: 1080 if (name.name[0] == '.' && name.name[1] == '.') 1081 return dget_parent(parent); 1082 break; 1083 case 1: 1084 if (name.name[0] == '.') 1085 return dget(parent); 1086 } 1087 name.hash = full_name_hash(name.name, name.len); 1088 dentry = d_lookup(parent, &name); 1089 if (dentry != NULL) 1090 return dentry; 1091 if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR)) 1092 return NULL; 1093 /* Note: caller is already holding the dir->i_mutex! */ 1094 dentry = d_alloc(parent, &name); 1095 if (dentry == NULL) 1096 return NULL; 1097 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 1098 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); 1099 if (!inode) { 1100 dput(dentry); 1101 return NULL; 1102 } 1103 alias = d_add_unique(dentry, inode); 1104 if (alias != NULL) { 1105 dput(dentry); 1106 dentry = alias; 1107 } 1108 nfs_renew_times(dentry); 1109 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1110 return dentry; 1111 } 1112 1113 /* 1114 * Code common to create, mkdir, and mknod. 1115 */ 1116 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, 1117 struct nfs_fattr *fattr) 1118 { 1119 struct inode *inode; 1120 int error = -EACCES; 1121 1122 /* We may have been initialized further down */ 1123 if (dentry->d_inode) 1124 return 0; 1125 if (fhandle->size == 0) { 1126 struct inode *dir = dentry->d_parent->d_inode; 1127 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); 1128 if (error) 1129 goto out_err; 1130 } 1131 if (!(fattr->valid & NFS_ATTR_FATTR)) { 1132 struct nfs_server *server = NFS_SB(dentry->d_sb); 1133 error = server->rpc_ops->getattr(server, fhandle, fattr); 1134 if (error < 0) 1135 goto out_err; 1136 } 1137 error = -ENOMEM; 1138 inode = nfs_fhget(dentry->d_sb, fhandle, fattr); 1139 if (inode == NULL) 1140 goto out_err; 1141 d_instantiate(dentry, inode); 1142 return 0; 1143 out_err: 1144 d_drop(dentry); 1145 return error; 1146 } 1147 1148 /* 1149 * Following a failed create operation, we drop the dentry rather 1150 * than retain a negative dentry. This avoids a problem in the event 1151 * that the operation succeeded on the server, but an error in the 1152 * reply path made it appear to have failed. 1153 */ 1154 static int nfs_create(struct inode *dir, struct dentry *dentry, int mode, 1155 struct nameidata *nd) 1156 { 1157 struct iattr attr; 1158 int error; 1159 int open_flags = 0; 1160 1161 dfprintk(VFS, "NFS: create(%s/%ld), %s\n", 1162 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1163 1164 attr.ia_mode = mode; 1165 attr.ia_valid = ATTR_MODE; 1166 1167 if (nd && (nd->flags & LOOKUP_CREATE)) 1168 open_flags = nd->intent.open.flags; 1169 1170 lock_kernel(); 1171 nfs_begin_data_update(dir); 1172 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd); 1173 nfs_end_data_update(dir); 1174 if (error != 0) 1175 goto out_err; 1176 nfs_renew_times(dentry); 1177 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1178 unlock_kernel(); 1179 return 0; 1180 out_err: 1181 unlock_kernel(); 1182 d_drop(dentry); 1183 return error; 1184 } 1185 1186 /* 1187 * See comments for nfs_proc_create regarding failed operations. 1188 */ 1189 static int 1190 nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev) 1191 { 1192 struct iattr attr; 1193 int status; 1194 1195 dfprintk(VFS, "NFS: mknod(%s/%ld), %s\n", 1196 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1197 1198 if (!new_valid_dev(rdev)) 1199 return -EINVAL; 1200 1201 attr.ia_mode = mode; 1202 attr.ia_valid = ATTR_MODE; 1203 1204 lock_kernel(); 1205 nfs_begin_data_update(dir); 1206 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); 1207 nfs_end_data_update(dir); 1208 if (status != 0) 1209 goto out_err; 1210 nfs_renew_times(dentry); 1211 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1212 unlock_kernel(); 1213 return 0; 1214 out_err: 1215 unlock_kernel(); 1216 d_drop(dentry); 1217 return status; 1218 } 1219 1220 /* 1221 * See comments for nfs_proc_create regarding failed operations. 1222 */ 1223 static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 1224 { 1225 struct iattr attr; 1226 int error; 1227 1228 dfprintk(VFS, "NFS: mkdir(%s/%ld), %s\n", 1229 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1230 1231 attr.ia_valid = ATTR_MODE; 1232 attr.ia_mode = mode | S_IFDIR; 1233 1234 lock_kernel(); 1235 nfs_begin_data_update(dir); 1236 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); 1237 nfs_end_data_update(dir); 1238 if (error != 0) 1239 goto out_err; 1240 nfs_renew_times(dentry); 1241 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1242 unlock_kernel(); 1243 return 0; 1244 out_err: 1245 d_drop(dentry); 1246 unlock_kernel(); 1247 return error; 1248 } 1249 1250 static int nfs_rmdir(struct inode *dir, struct dentry *dentry) 1251 { 1252 int error; 1253 1254 dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n", 1255 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1256 1257 lock_kernel(); 1258 nfs_begin_data_update(dir); 1259 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 1260 /* Ensure the VFS deletes this inode */ 1261 if (error == 0 && dentry->d_inode != NULL) 1262 dentry->d_inode->i_nlink = 0; 1263 nfs_end_data_update(dir); 1264 unlock_kernel(); 1265 1266 return error; 1267 } 1268 1269 static int nfs_sillyrename(struct inode *dir, struct dentry *dentry) 1270 { 1271 static unsigned int sillycounter; 1272 const int i_inosize = sizeof(dir->i_ino)*2; 1273 const int countersize = sizeof(sillycounter)*2; 1274 const int slen = sizeof(".nfs") + i_inosize + countersize - 1; 1275 char silly[slen+1]; 1276 struct qstr qsilly; 1277 struct dentry *sdentry; 1278 int error = -EIO; 1279 1280 dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n", 1281 dentry->d_parent->d_name.name, dentry->d_name.name, 1282 atomic_read(&dentry->d_count)); 1283 nfs_inc_stats(dir, NFSIOS_SILLYRENAME); 1284 1285 #ifdef NFS_PARANOIA 1286 if (!dentry->d_inode) 1287 printk("NFS: silly-renaming %s/%s, negative dentry??\n", 1288 dentry->d_parent->d_name.name, dentry->d_name.name); 1289 #endif 1290 /* 1291 * We don't allow a dentry to be silly-renamed twice. 1292 */ 1293 error = -EBUSY; 1294 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 1295 goto out; 1296 1297 sprintf(silly, ".nfs%*.*lx", 1298 i_inosize, i_inosize, dentry->d_inode->i_ino); 1299 1300 /* Return delegation in anticipation of the rename */ 1301 nfs_inode_return_delegation(dentry->d_inode); 1302 1303 sdentry = NULL; 1304 do { 1305 char *suffix = silly + slen - countersize; 1306 1307 dput(sdentry); 1308 sillycounter++; 1309 sprintf(suffix, "%*.*x", countersize, countersize, sillycounter); 1310 1311 dfprintk(VFS, "NFS: trying to rename %s to %s\n", 1312 dentry->d_name.name, silly); 1313 1314 sdentry = lookup_one_len(silly, dentry->d_parent, slen); 1315 /* 1316 * N.B. Better to return EBUSY here ... it could be 1317 * dangerous to delete the file while it's in use. 1318 */ 1319 if (IS_ERR(sdentry)) 1320 goto out; 1321 } while(sdentry->d_inode != NULL); /* need negative lookup */ 1322 1323 qsilly.name = silly; 1324 qsilly.len = strlen(silly); 1325 nfs_begin_data_update(dir); 1326 if (dentry->d_inode) { 1327 nfs_begin_data_update(dentry->d_inode); 1328 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, 1329 dir, &qsilly); 1330 nfs_mark_for_revalidate(dentry->d_inode); 1331 nfs_end_data_update(dentry->d_inode); 1332 } else 1333 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, 1334 dir, &qsilly); 1335 nfs_end_data_update(dir); 1336 if (!error) { 1337 nfs_renew_times(dentry); 1338 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1339 d_move(dentry, sdentry); 1340 error = nfs_async_unlink(dentry); 1341 /* If we return 0 we don't unlink */ 1342 } 1343 dput(sdentry); 1344 out: 1345 return error; 1346 } 1347 1348 /* 1349 * Remove a file after making sure there are no pending writes, 1350 * and after checking that the file has only one user. 1351 * 1352 * We invalidate the attribute cache and free the inode prior to the operation 1353 * to avoid possible races if the server reuses the inode. 1354 */ 1355 static int nfs_safe_remove(struct dentry *dentry) 1356 { 1357 struct inode *dir = dentry->d_parent->d_inode; 1358 struct inode *inode = dentry->d_inode; 1359 int error = -EBUSY; 1360 1361 dfprintk(VFS, "NFS: safe_remove(%s/%s)\n", 1362 dentry->d_parent->d_name.name, dentry->d_name.name); 1363 1364 /* If the dentry was sillyrenamed, we simply call d_delete() */ 1365 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1366 error = 0; 1367 goto out; 1368 } 1369 1370 nfs_begin_data_update(dir); 1371 if (inode != NULL) { 1372 nfs_inode_return_delegation(inode); 1373 nfs_begin_data_update(inode); 1374 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1375 /* The VFS may want to delete this inode */ 1376 if (error == 0) 1377 inode->i_nlink--; 1378 nfs_mark_for_revalidate(inode); 1379 nfs_end_data_update(inode); 1380 } else 1381 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1382 nfs_end_data_update(dir); 1383 out: 1384 return error; 1385 } 1386 1387 /* We do silly rename. In case sillyrename() returns -EBUSY, the inode 1388 * belongs to an active ".nfs..." file and we return -EBUSY. 1389 * 1390 * If sillyrename() returns 0, we do nothing, otherwise we unlink. 1391 */ 1392 static int nfs_unlink(struct inode *dir, struct dentry *dentry) 1393 { 1394 int error; 1395 int need_rehash = 0; 1396 1397 dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id, 1398 dir->i_ino, dentry->d_name.name); 1399 1400 lock_kernel(); 1401 spin_lock(&dcache_lock); 1402 spin_lock(&dentry->d_lock); 1403 if (atomic_read(&dentry->d_count) > 1) { 1404 spin_unlock(&dentry->d_lock); 1405 spin_unlock(&dcache_lock); 1406 error = nfs_sillyrename(dir, dentry); 1407 unlock_kernel(); 1408 return error; 1409 } 1410 if (!d_unhashed(dentry)) { 1411 __d_drop(dentry); 1412 need_rehash = 1; 1413 } 1414 spin_unlock(&dentry->d_lock); 1415 spin_unlock(&dcache_lock); 1416 error = nfs_safe_remove(dentry); 1417 if (!error) { 1418 nfs_renew_times(dentry); 1419 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1420 } else if (need_rehash) 1421 d_rehash(dentry); 1422 unlock_kernel(); 1423 return error; 1424 } 1425 1426 static int 1427 nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) 1428 { 1429 struct iattr attr; 1430 struct nfs_fattr sym_attr; 1431 struct nfs_fh sym_fh; 1432 struct qstr qsymname; 1433 int error; 1434 1435 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id, 1436 dir->i_ino, dentry->d_name.name, symname); 1437 1438 #ifdef NFS_PARANOIA 1439 if (dentry->d_inode) 1440 printk("nfs_proc_symlink: %s/%s not negative!\n", 1441 dentry->d_parent->d_name.name, dentry->d_name.name); 1442 #endif 1443 /* 1444 * Fill in the sattr for the call. 1445 * Note: SunOS 4.1.2 crashes if the mode isn't initialized! 1446 */ 1447 attr.ia_valid = ATTR_MODE; 1448 attr.ia_mode = S_IFLNK | S_IRWXUGO; 1449 1450 qsymname.name = symname; 1451 qsymname.len = strlen(symname); 1452 1453 lock_kernel(); 1454 nfs_begin_data_update(dir); 1455 error = NFS_PROTO(dir)->symlink(dir, &dentry->d_name, &qsymname, 1456 &attr, &sym_fh, &sym_attr); 1457 nfs_end_data_update(dir); 1458 if (!error) { 1459 error = nfs_instantiate(dentry, &sym_fh, &sym_attr); 1460 } else { 1461 if (error == -EEXIST) 1462 printk("nfs_proc_symlink: %s/%s already exists??\n", 1463 dentry->d_parent->d_name.name, dentry->d_name.name); 1464 d_drop(dentry); 1465 } 1466 unlock_kernel(); 1467 return error; 1468 } 1469 1470 static int 1471 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 1472 { 1473 struct inode *inode = old_dentry->d_inode; 1474 int error; 1475 1476 dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n", 1477 old_dentry->d_parent->d_name.name, old_dentry->d_name.name, 1478 dentry->d_parent->d_name.name, dentry->d_name.name); 1479 1480 lock_kernel(); 1481 nfs_begin_data_update(dir); 1482 nfs_begin_data_update(inode); 1483 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 1484 if (error == 0) { 1485 atomic_inc(&inode->i_count); 1486 d_instantiate(dentry, inode); 1487 } 1488 nfs_end_data_update(inode); 1489 nfs_end_data_update(dir); 1490 unlock_kernel(); 1491 return error; 1492 } 1493 1494 /* 1495 * RENAME 1496 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a 1497 * different file handle for the same inode after a rename (e.g. when 1498 * moving to a different directory). A fail-safe method to do so would 1499 * be to look up old_dir/old_name, create a link to new_dir/new_name and 1500 * rename the old file using the sillyrename stuff. This way, the original 1501 * file in old_dir will go away when the last process iput()s the inode. 1502 * 1503 * FIXED. 1504 * 1505 * It actually works quite well. One needs to have the possibility for 1506 * at least one ".nfs..." file in each directory the file ever gets 1507 * moved or linked to which happens automagically with the new 1508 * implementation that only depends on the dcache stuff instead of 1509 * using the inode layer 1510 * 1511 * Unfortunately, things are a little more complicated than indicated 1512 * above. For a cross-directory move, we want to make sure we can get 1513 * rid of the old inode after the operation. This means there must be 1514 * no pending writes (if it's a file), and the use count must be 1. 1515 * If these conditions are met, we can drop the dentries before doing 1516 * the rename. 1517 */ 1518 static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, 1519 struct inode *new_dir, struct dentry *new_dentry) 1520 { 1521 struct inode *old_inode = old_dentry->d_inode; 1522 struct inode *new_inode = new_dentry->d_inode; 1523 struct dentry *dentry = NULL, *rehash = NULL; 1524 int error = -EBUSY; 1525 1526 /* 1527 * To prevent any new references to the target during the rename, 1528 * we unhash the dentry and free the inode in advance. 1529 */ 1530 lock_kernel(); 1531 if (!d_unhashed(new_dentry)) { 1532 d_drop(new_dentry); 1533 rehash = new_dentry; 1534 } 1535 1536 dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n", 1537 old_dentry->d_parent->d_name.name, old_dentry->d_name.name, 1538 new_dentry->d_parent->d_name.name, new_dentry->d_name.name, 1539 atomic_read(&new_dentry->d_count)); 1540 1541 /* 1542 * First check whether the target is busy ... we can't 1543 * safely do _any_ rename if the target is in use. 1544 * 1545 * For files, make a copy of the dentry and then do a 1546 * silly-rename. If the silly-rename succeeds, the 1547 * copied dentry is hashed and becomes the new target. 1548 */ 1549 if (!new_inode) 1550 goto go_ahead; 1551 if (S_ISDIR(new_inode->i_mode)) { 1552 error = -EISDIR; 1553 if (!S_ISDIR(old_inode->i_mode)) 1554 goto out; 1555 } else if (atomic_read(&new_dentry->d_count) > 2) { 1556 int err; 1557 /* copy the target dentry's name */ 1558 dentry = d_alloc(new_dentry->d_parent, 1559 &new_dentry->d_name); 1560 if (!dentry) 1561 goto out; 1562 1563 /* silly-rename the existing target ... */ 1564 err = nfs_sillyrename(new_dir, new_dentry); 1565 if (!err) { 1566 new_dentry = rehash = dentry; 1567 new_inode = NULL; 1568 /* instantiate the replacement target */ 1569 d_instantiate(new_dentry, NULL); 1570 } else if (atomic_read(&new_dentry->d_count) > 1) { 1571 /* dentry still busy? */ 1572 #ifdef NFS_PARANOIA 1573 printk("nfs_rename: target %s/%s busy, d_count=%d\n", 1574 new_dentry->d_parent->d_name.name, 1575 new_dentry->d_name.name, 1576 atomic_read(&new_dentry->d_count)); 1577 #endif 1578 goto out; 1579 } 1580 } else 1581 new_inode->i_nlink--; 1582 1583 go_ahead: 1584 /* 1585 * ... prune child dentries and writebacks if needed. 1586 */ 1587 if (atomic_read(&old_dentry->d_count) > 1) { 1588 nfs_wb_all(old_inode); 1589 shrink_dcache_parent(old_dentry); 1590 } 1591 nfs_inode_return_delegation(old_inode); 1592 1593 if (new_inode != NULL) { 1594 nfs_inode_return_delegation(new_inode); 1595 d_delete(new_dentry); 1596 } 1597 1598 nfs_begin_data_update(old_dir); 1599 nfs_begin_data_update(new_dir); 1600 nfs_begin_data_update(old_inode); 1601 error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name, 1602 new_dir, &new_dentry->d_name); 1603 nfs_mark_for_revalidate(old_inode); 1604 nfs_end_data_update(old_inode); 1605 nfs_end_data_update(new_dir); 1606 nfs_end_data_update(old_dir); 1607 out: 1608 if (rehash) 1609 d_rehash(rehash); 1610 if (!error) { 1611 if (!S_ISDIR(old_inode->i_mode)) 1612 d_move(old_dentry, new_dentry); 1613 nfs_renew_times(new_dentry); 1614 nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir)); 1615 } 1616 1617 /* new dentry created? */ 1618 if (dentry) 1619 dput(dentry); 1620 unlock_kernel(); 1621 return error; 1622 } 1623 1624 int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) 1625 { 1626 struct nfs_inode *nfsi = NFS_I(inode); 1627 struct nfs_access_entry *cache = &nfsi->cache_access; 1628 1629 if (cache->cred != cred 1630 || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode)) 1631 || (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)) 1632 return -ENOENT; 1633 memcpy(res, cache, sizeof(*res)); 1634 return 0; 1635 } 1636 1637 void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) 1638 { 1639 struct nfs_inode *nfsi = NFS_I(inode); 1640 struct nfs_access_entry *cache = &nfsi->cache_access; 1641 1642 if (cache->cred != set->cred) { 1643 if (cache->cred) 1644 put_rpccred(cache->cred); 1645 cache->cred = get_rpccred(set->cred); 1646 } 1647 /* FIXME: replace current access_cache BKL reliance with inode->i_lock */ 1648 spin_lock(&inode->i_lock); 1649 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; 1650 spin_unlock(&inode->i_lock); 1651 cache->jiffies = set->jiffies; 1652 cache->mask = set->mask; 1653 } 1654 1655 static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) 1656 { 1657 struct nfs_access_entry cache; 1658 int status; 1659 1660 status = nfs_access_get_cached(inode, cred, &cache); 1661 if (status == 0) 1662 goto out; 1663 1664 /* Be clever: ask server to check for all possible rights */ 1665 cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ; 1666 cache.cred = cred; 1667 cache.jiffies = jiffies; 1668 status = NFS_PROTO(inode)->access(inode, &cache); 1669 if (status != 0) 1670 return status; 1671 nfs_access_add_cache(inode, &cache); 1672 out: 1673 if ((cache.mask & mask) == mask) 1674 return 0; 1675 return -EACCES; 1676 } 1677 1678 int nfs_permission(struct inode *inode, int mask, struct nameidata *nd) 1679 { 1680 struct rpc_cred *cred; 1681 int res = 0; 1682 1683 nfs_inc_stats(inode, NFSIOS_VFSACCESS); 1684 1685 if (mask == 0) 1686 goto out; 1687 /* Is this sys_access() ? */ 1688 if (nd != NULL && (nd->flags & LOOKUP_ACCESS)) 1689 goto force_lookup; 1690 1691 switch (inode->i_mode & S_IFMT) { 1692 case S_IFLNK: 1693 goto out; 1694 case S_IFREG: 1695 /* NFSv4 has atomic_open... */ 1696 if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN) 1697 && nd != NULL 1698 && (nd->flags & LOOKUP_OPEN)) 1699 goto out; 1700 break; 1701 case S_IFDIR: 1702 /* 1703 * Optimize away all write operations, since the server 1704 * will check permissions when we perform the op. 1705 */ 1706 if ((mask & MAY_WRITE) && !(mask & MAY_READ)) 1707 goto out; 1708 } 1709 1710 force_lookup: 1711 lock_kernel(); 1712 1713 if (!NFS_PROTO(inode)->access) 1714 goto out_notsup; 1715 1716 cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0); 1717 if (!IS_ERR(cred)) { 1718 res = nfs_do_access(inode, cred, mask); 1719 put_rpccred(cred); 1720 } else 1721 res = PTR_ERR(cred); 1722 unlock_kernel(); 1723 out: 1724 dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n", 1725 inode->i_sb->s_id, inode->i_ino, mask, res); 1726 return res; 1727 out_notsup: 1728 res = nfs_revalidate_inode(NFS_SERVER(inode), inode); 1729 if (res == 0) 1730 res = generic_permission(inode, mask, NULL); 1731 unlock_kernel(); 1732 goto out; 1733 } 1734 1735 /* 1736 * Local variables: 1737 * version-control: t 1738 * kept-new-versions: 5 1739 * End: 1740 */ 1741