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 SetPageError(page); 215 unlock_page(page); 216 nfs_zap_caches(inode); 217 desc->error = error; 218 return -EIO; 219 } 220 221 static inline 222 int dir_decode(nfs_readdir_descriptor_t *desc) 223 { 224 __be32 *p = desc->ptr; 225 p = desc->decode(p, desc->entry, desc->plus); 226 if (IS_ERR(p)) 227 return PTR_ERR(p); 228 desc->ptr = p; 229 if (desc->timestamp_valid) 230 desc->entry->fattr->time_start = desc->timestamp; 231 else 232 desc->entry->fattr->valid &= ~NFS_ATTR_FATTR; 233 return 0; 234 } 235 236 static inline 237 void dir_page_release(nfs_readdir_descriptor_t *desc) 238 { 239 kunmap(desc->page); 240 page_cache_release(desc->page); 241 desc->page = NULL; 242 desc->ptr = NULL; 243 } 244 245 /* 246 * Given a pointer to a buffer that has already been filled by a call 247 * to readdir, find the next entry with cookie '*desc->dir_cookie'. 248 * 249 * If the end of the buffer has been reached, return -EAGAIN, if not, 250 * return the offset within the buffer of the next entry to be 251 * read. 252 */ 253 static inline 254 int find_dirent(nfs_readdir_descriptor_t *desc) 255 { 256 struct nfs_entry *entry = desc->entry; 257 int loop_count = 0, 258 status; 259 260 while((status = dir_decode(desc)) == 0) { 261 dfprintk(DIRCACHE, "NFS: %s: examining cookie %Lu\n", 262 __FUNCTION__, (unsigned long long)entry->cookie); 263 if (entry->prev_cookie == *desc->dir_cookie) 264 break; 265 if (loop_count++ > 200) { 266 loop_count = 0; 267 schedule(); 268 } 269 } 270 return status; 271 } 272 273 /* 274 * Given a pointer to a buffer that has already been filled by a call 275 * to readdir, find the entry at offset 'desc->file->f_pos'. 276 * 277 * If the end of the buffer has been reached, return -EAGAIN, if not, 278 * return the offset within the buffer of the next entry to be 279 * read. 280 */ 281 static inline 282 int find_dirent_index(nfs_readdir_descriptor_t *desc) 283 { 284 struct nfs_entry *entry = desc->entry; 285 int loop_count = 0, 286 status; 287 288 for(;;) { 289 status = dir_decode(desc); 290 if (status) 291 break; 292 293 dfprintk(DIRCACHE, "NFS: found cookie %Lu at index %Ld\n", 294 (unsigned long long)entry->cookie, desc->current_index); 295 296 if (desc->file->f_pos == desc->current_index) { 297 *desc->dir_cookie = entry->cookie; 298 break; 299 } 300 desc->current_index++; 301 if (loop_count++ > 200) { 302 loop_count = 0; 303 schedule(); 304 } 305 } 306 return status; 307 } 308 309 /* 310 * Find the given page, and call find_dirent() or find_dirent_index in 311 * order to try to return the next entry. 312 */ 313 static inline 314 int find_dirent_page(nfs_readdir_descriptor_t *desc) 315 { 316 struct inode *inode = desc->file->f_path.dentry->d_inode; 317 struct page *page; 318 int status; 319 320 dfprintk(DIRCACHE, "NFS: %s: searching page %ld for target %Lu\n", 321 __FUNCTION__, desc->page_index, 322 (long long) *desc->dir_cookie); 323 324 /* If we find the page in the page_cache, we cannot be sure 325 * how fresh the data is, so we will ignore readdir_plus attributes. 326 */ 327 desc->timestamp_valid = 0; 328 page = read_cache_page(inode->i_mapping, desc->page_index, 329 (filler_t *)nfs_readdir_filler, desc); 330 if (IS_ERR(page)) { 331 status = PTR_ERR(page); 332 goto out; 333 } 334 335 /* NOTE: Someone else may have changed the READDIRPLUS flag */ 336 desc->page = page; 337 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ 338 if (*desc->dir_cookie != 0) 339 status = find_dirent(desc); 340 else 341 status = find_dirent_index(desc); 342 if (status < 0) 343 dir_page_release(desc); 344 out: 345 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, status); 346 return status; 347 } 348 349 /* 350 * Recurse through the page cache pages, and return a 351 * filled nfs_entry structure of the next directory entry if possible. 352 * 353 * The target for the search is '*desc->dir_cookie' if non-0, 354 * 'desc->file->f_pos' otherwise 355 */ 356 static inline 357 int readdir_search_pagecache(nfs_readdir_descriptor_t *desc) 358 { 359 int loop_count = 0; 360 int res; 361 362 /* Always search-by-index from the beginning of the cache */ 363 if (*desc->dir_cookie == 0) { 364 dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for offset %Ld\n", 365 (long long)desc->file->f_pos); 366 desc->page_index = 0; 367 desc->entry->cookie = desc->entry->prev_cookie = 0; 368 desc->entry->eof = 0; 369 desc->current_index = 0; 370 } else 371 dfprintk(DIRCACHE, "NFS: readdir_search_pagecache() searching for cookie %Lu\n", 372 (unsigned long long)*desc->dir_cookie); 373 374 for (;;) { 375 res = find_dirent_page(desc); 376 if (res != -EAGAIN) 377 break; 378 /* Align to beginning of next page */ 379 desc->page_index ++; 380 if (loop_count++ > 200) { 381 loop_count = 0; 382 schedule(); 383 } 384 } 385 386 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __FUNCTION__, res); 387 return res; 388 } 389 390 static inline unsigned int dt_type(struct inode *inode) 391 { 392 return (inode->i_mode >> 12) & 15; 393 } 394 395 static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc); 396 397 /* 398 * Once we've found the start of the dirent within a page: fill 'er up... 399 */ 400 static 401 int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent, 402 filldir_t filldir) 403 { 404 struct file *file = desc->file; 405 struct nfs_entry *entry = desc->entry; 406 struct dentry *dentry = NULL; 407 u64 fileid; 408 int loop_count = 0, 409 res; 410 411 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling starting @ cookie %Lu\n", 412 (unsigned long long)entry->cookie); 413 414 for(;;) { 415 unsigned d_type = DT_UNKNOWN; 416 /* Note: entry->prev_cookie contains the cookie for 417 * retrieving the current dirent on the server */ 418 fileid = entry->ino; 419 420 /* Get a dentry if we have one */ 421 if (dentry != NULL) 422 dput(dentry); 423 dentry = nfs_readdir_lookup(desc); 424 425 /* Use readdirplus info */ 426 if (dentry != NULL && dentry->d_inode != NULL) { 427 d_type = dt_type(dentry->d_inode); 428 fileid = NFS_FILEID(dentry->d_inode); 429 } 430 431 res = filldir(dirent, entry->name, entry->len, 432 file->f_pos, fileid, d_type); 433 if (res < 0) 434 break; 435 file->f_pos++; 436 *desc->dir_cookie = entry->cookie; 437 if (dir_decode(desc) != 0) { 438 desc->page_index ++; 439 break; 440 } 441 if (loop_count++ > 200) { 442 loop_count = 0; 443 schedule(); 444 } 445 } 446 dir_page_release(desc); 447 if (dentry != NULL) 448 dput(dentry); 449 dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", 450 (unsigned long long)*desc->dir_cookie, res); 451 return res; 452 } 453 454 /* 455 * If we cannot find a cookie in our cache, we suspect that this is 456 * because it points to a deleted file, so we ask the server to return 457 * whatever it thinks is the next entry. We then feed this to filldir. 458 * If all goes well, we should then be able to find our way round the 459 * cache on the next call to readdir_search_pagecache(); 460 * 461 * NOTE: we cannot add the anonymous page to the pagecache because 462 * the data it contains might not be page aligned. Besides, 463 * we should already have a complete representation of the 464 * directory in the page cache by the time we get here. 465 */ 466 static inline 467 int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent, 468 filldir_t filldir) 469 { 470 struct file *file = desc->file; 471 struct inode *inode = file->f_path.dentry->d_inode; 472 struct rpc_cred *cred = nfs_file_cred(file); 473 struct page *page = NULL; 474 int status; 475 unsigned long timestamp; 476 477 dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n", 478 (unsigned long long)*desc->dir_cookie); 479 480 page = alloc_page(GFP_HIGHUSER); 481 if (!page) { 482 status = -ENOMEM; 483 goto out; 484 } 485 timestamp = jiffies; 486 desc->error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, *desc->dir_cookie, 487 page, 488 NFS_SERVER(inode)->dtsize, 489 desc->plus); 490 desc->page = page; 491 desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */ 492 if (desc->error >= 0) { 493 desc->timestamp = timestamp; 494 desc->timestamp_valid = 1; 495 if ((status = dir_decode(desc)) == 0) 496 desc->entry->prev_cookie = *desc->dir_cookie; 497 } else 498 status = -EIO; 499 if (status < 0) 500 goto out_release; 501 502 status = nfs_do_filldir(desc, dirent, filldir); 503 504 /* Reset read descriptor so it searches the page cache from 505 * the start upon the next call to readdir_search_pagecache() */ 506 desc->page_index = 0; 507 desc->entry->cookie = desc->entry->prev_cookie = 0; 508 desc->entry->eof = 0; 509 out: 510 dfprintk(DIRCACHE, "NFS: %s: returns %d\n", 511 __FUNCTION__, status); 512 return status; 513 out_release: 514 dir_page_release(desc); 515 goto out; 516 } 517 518 /* The file offset position represents the dirent entry number. A 519 last cookie cache takes care of the common case of reading the 520 whole directory. 521 */ 522 static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir) 523 { 524 struct dentry *dentry = filp->f_path.dentry; 525 struct inode *inode = dentry->d_inode; 526 nfs_readdir_descriptor_t my_desc, 527 *desc = &my_desc; 528 struct nfs_entry my_entry; 529 struct nfs_fh fh; 530 struct nfs_fattr fattr; 531 long res; 532 533 dfprintk(VFS, "NFS: readdir(%s/%s) starting at cookie %Lu\n", 534 dentry->d_parent->d_name.name, dentry->d_name.name, 535 (long long)filp->f_pos); 536 nfs_inc_stats(inode, NFSIOS_VFSGETDENTS); 537 538 lock_kernel(); 539 540 res = nfs_revalidate_mapping_nolock(inode, filp->f_mapping); 541 if (res < 0) { 542 unlock_kernel(); 543 return res; 544 } 545 546 /* 547 * filp->f_pos points to the dirent entry number. 548 * *desc->dir_cookie has the cookie for the next entry. We have 549 * to either find the entry with the appropriate number or 550 * revalidate the cookie. 551 */ 552 memset(desc, 0, sizeof(*desc)); 553 554 desc->file = filp; 555 desc->dir_cookie = &nfs_file_open_context(filp)->dir_cookie; 556 desc->decode = NFS_PROTO(inode)->decode_dirent; 557 desc->plus = NFS_USE_READDIRPLUS(inode); 558 559 my_entry.cookie = my_entry.prev_cookie = 0; 560 my_entry.eof = 0; 561 my_entry.fh = &fh; 562 my_entry.fattr = &fattr; 563 nfs_fattr_init(&fattr); 564 desc->entry = &my_entry; 565 566 while(!desc->entry->eof) { 567 res = readdir_search_pagecache(desc); 568 569 if (res == -EBADCOOKIE) { 570 /* This means either end of directory */ 571 if (*desc->dir_cookie && desc->entry->cookie != *desc->dir_cookie) { 572 /* Or that the server has 'lost' a cookie */ 573 res = uncached_readdir(desc, dirent, filldir); 574 if (res >= 0) 575 continue; 576 } 577 res = 0; 578 break; 579 } 580 if (res == -ETOOSMALL && desc->plus) { 581 clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode)); 582 nfs_zap_caches(inode); 583 desc->plus = 0; 584 desc->entry->eof = 0; 585 continue; 586 } 587 if (res < 0) 588 break; 589 590 res = nfs_do_filldir(desc, dirent, filldir); 591 if (res < 0) { 592 res = 0; 593 break; 594 } 595 } 596 unlock_kernel(); 597 if (res > 0) 598 res = 0; 599 dfprintk(VFS, "NFS: readdir(%s/%s) returns %ld\n", 600 dentry->d_parent->d_name.name, dentry->d_name.name, 601 res); 602 return res; 603 } 604 605 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int origin) 606 { 607 mutex_lock(&filp->f_path.dentry->d_inode->i_mutex); 608 switch (origin) { 609 case 1: 610 offset += filp->f_pos; 611 case 0: 612 if (offset >= 0) 613 break; 614 default: 615 offset = -EINVAL; 616 goto out; 617 } 618 if (offset != filp->f_pos) { 619 filp->f_pos = offset; 620 nfs_file_open_context(filp)->dir_cookie = 0; 621 } 622 out: 623 mutex_unlock(&filp->f_path.dentry->d_inode->i_mutex); 624 return offset; 625 } 626 627 /* 628 * All directory operations under NFS are synchronous, so fsync() 629 * is a dummy operation. 630 */ 631 static int nfs_fsync_dir(struct file *filp, struct dentry *dentry, int datasync) 632 { 633 dfprintk(VFS, "NFS: fsync_dir(%s/%s) datasync %d\n", 634 dentry->d_parent->d_name.name, dentry->d_name.name, 635 datasync); 636 637 return 0; 638 } 639 640 /* 641 * A check for whether or not the parent directory has changed. 642 * In the case it has, we assume that the dentries are untrustworthy 643 * and may need to be looked up again. 644 */ 645 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry) 646 { 647 if (IS_ROOT(dentry)) 648 return 1; 649 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 650 return 0; 651 /* Revalidate nfsi->cache_change_attribute before we declare a match */ 652 if (nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0) 653 return 0; 654 if (!nfs_verify_change_attribute(dir, dentry->d_time)) 655 return 0; 656 return 1; 657 } 658 659 static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf) 660 { 661 dentry->d_time = verf; 662 } 663 664 /* 665 * Return the intent data that applies to this particular path component 666 * 667 * Note that the current set of intents only apply to the very last 668 * component of the path. 669 * We check for this using LOOKUP_CONTINUE and LOOKUP_PARENT. 670 */ 671 static inline unsigned int nfs_lookup_check_intent(struct nameidata *nd, unsigned int mask) 672 { 673 if (nd->flags & (LOOKUP_CONTINUE|LOOKUP_PARENT)) 674 return 0; 675 return nd->flags & mask; 676 } 677 678 /* 679 * Inode and filehandle revalidation for lookups. 680 * 681 * We force revalidation in the cases where the VFS sets LOOKUP_REVAL, 682 * or if the intent information indicates that we're about to open this 683 * particular file and the "nocto" mount flag is not set. 684 * 685 */ 686 static inline 687 int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd) 688 { 689 struct nfs_server *server = NFS_SERVER(inode); 690 691 if (nd != NULL) { 692 /* VFS wants an on-the-wire revalidation */ 693 if (nd->flags & LOOKUP_REVAL) 694 goto out_force; 695 /* This is an open(2) */ 696 if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0 && 697 !(server->flags & NFS_MOUNT_NOCTO) && 698 (S_ISREG(inode->i_mode) || 699 S_ISDIR(inode->i_mode))) 700 goto out_force; 701 } 702 return nfs_revalidate_inode(server, inode); 703 out_force: 704 return __nfs_revalidate_inode(server, inode); 705 } 706 707 /* 708 * We judge how long we want to trust negative 709 * dentries by looking at the parent inode mtime. 710 * 711 * If parent mtime has changed, we revalidate, else we wait for a 712 * period corresponding to the parent's attribute cache timeout value. 713 */ 714 static inline 715 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 716 struct nameidata *nd) 717 { 718 /* Don't revalidate a negative dentry if we're creating a new file */ 719 if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0) 720 return 0; 721 return !nfs_check_verifier(dir, dentry); 722 } 723 724 /* 725 * This is called every time the dcache has a lookup hit, 726 * and we should check whether we can really trust that 727 * lookup. 728 * 729 * NOTE! The hit can be a negative hit too, don't assume 730 * we have an inode! 731 * 732 * If the parent directory is seen to have changed, we throw out the 733 * cached dentry and do a new lookup. 734 */ 735 static int nfs_lookup_revalidate(struct dentry * dentry, struct nameidata *nd) 736 { 737 struct inode *dir; 738 struct inode *inode; 739 struct dentry *parent; 740 int error; 741 struct nfs_fh fhandle; 742 struct nfs_fattr fattr; 743 744 parent = dget_parent(dentry); 745 lock_kernel(); 746 dir = parent->d_inode; 747 nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE); 748 inode = dentry->d_inode; 749 750 if (!inode) { 751 if (nfs_neg_need_reval(dir, dentry, nd)) 752 goto out_bad; 753 goto out_valid; 754 } 755 756 if (is_bad_inode(inode)) { 757 dfprintk(LOOKUPCACHE, "%s: %s/%s has dud inode\n", 758 __FUNCTION__, dentry->d_parent->d_name.name, 759 dentry->d_name.name); 760 goto out_bad; 761 } 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 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); 774 if (error) 775 goto out_bad; 776 if (nfs_compare_fh(NFS_FH(inode), &fhandle)) 777 goto out_bad; 778 if ((error = nfs_refresh_inode(inode, &fattr)) != 0) 779 goto out_bad; 780 781 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 782 out_valid: 783 unlock_kernel(); 784 dput(parent); 785 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is valid\n", 786 __FUNCTION__, dentry->d_parent->d_name.name, 787 dentry->d_name.name); 788 return 1; 789 out_zap_parent: 790 nfs_zap_caches(dir); 791 out_bad: 792 nfs_mark_for_revalidate(dir); 793 if (inode && S_ISDIR(inode->i_mode)) { 794 /* Purge readdir caches. */ 795 nfs_zap_caches(inode); 796 /* If we have submounts, don't unhash ! */ 797 if (have_submounts(dentry)) 798 goto out_valid; 799 shrink_dcache_parent(dentry); 800 } 801 d_drop(dentry); 802 unlock_kernel(); 803 dput(parent); 804 dfprintk(LOOKUPCACHE, "NFS: %s(%s/%s) is invalid\n", 805 __FUNCTION__, dentry->d_parent->d_name.name, 806 dentry->d_name.name); 807 return 0; 808 } 809 810 /* 811 * This is called from dput() when d_count is going to 0. 812 */ 813 static int nfs_dentry_delete(struct dentry *dentry) 814 { 815 dfprintk(VFS, "NFS: dentry_delete(%s/%s, %x)\n", 816 dentry->d_parent->d_name.name, dentry->d_name.name, 817 dentry->d_flags); 818 819 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 820 /* Unhash it, so that ->d_iput() would be called */ 821 return 1; 822 } 823 if (!(dentry->d_sb->s_flags & MS_ACTIVE)) { 824 /* Unhash it, so that ancestors of killed async unlink 825 * files will be cleaned up during umount */ 826 return 1; 827 } 828 return 0; 829 830 } 831 832 /* 833 * Called when the dentry loses inode. 834 * We use it to clean up silly-renamed files. 835 */ 836 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode) 837 { 838 nfs_inode_return_delegation(inode); 839 if (S_ISDIR(inode->i_mode)) 840 /* drop any readdir cache as it could easily be old */ 841 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA; 842 843 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 844 lock_kernel(); 845 drop_nlink(inode); 846 nfs_complete_unlink(dentry, inode); 847 unlock_kernel(); 848 } 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 inline int nfs_reval_fsid(struct inode *dir, const struct nfs_fattr *fattr) 873 { 874 struct nfs_server *server = NFS_SERVER(dir); 875 876 if (!nfs_fsid_equal(&server->fsid, &fattr->fsid)) 877 /* Revalidate fsid using the parent directory */ 878 return __nfs_revalidate_inode(server, dir); 879 return 0; 880 } 881 882 static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) 883 { 884 struct dentry *res; 885 struct inode *inode = NULL; 886 int error; 887 struct nfs_fh fhandle; 888 struct nfs_fattr fattr; 889 890 dfprintk(VFS, "NFS: lookup(%s/%s)\n", 891 dentry->d_parent->d_name.name, dentry->d_name.name); 892 nfs_inc_stats(dir, NFSIOS_VFSLOOKUP); 893 894 res = ERR_PTR(-ENAMETOOLONG); 895 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) 896 goto out; 897 898 res = ERR_PTR(-ENOMEM); 899 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 900 901 lock_kernel(); 902 903 /* 904 * If we're doing an exclusive create, optimize away the lookup 905 * but don't hash the dentry. 906 */ 907 if (nfs_is_exclusive_create(dir, nd)) { 908 d_instantiate(dentry, NULL); 909 res = NULL; 910 goto out_unlock; 911 } 912 913 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); 914 if (error == -ENOENT) 915 goto no_entry; 916 if (error < 0) { 917 res = ERR_PTR(error); 918 goto out_unlock; 919 } 920 error = nfs_reval_fsid(dir, &fattr); 921 if (error < 0) { 922 res = ERR_PTR(error); 923 goto out_unlock; 924 } 925 inode = nfs_fhget(dentry->d_sb, &fhandle, &fattr); 926 res = (struct dentry *)inode; 927 if (IS_ERR(res)) 928 goto out_unlock; 929 930 no_entry: 931 res = d_materialise_unique(dentry, inode); 932 if (res != NULL) { 933 if (IS_ERR(res)) 934 goto out_unlock; 935 dentry = res; 936 } 937 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 938 out_unlock: 939 unlock_kernel(); 940 out: 941 return res; 942 } 943 944 #ifdef CONFIG_NFS_V4 945 static int nfs_open_revalidate(struct dentry *, struct nameidata *); 946 947 struct dentry_operations nfs4_dentry_operations = { 948 .d_revalidate = nfs_open_revalidate, 949 .d_delete = nfs_dentry_delete, 950 .d_iput = nfs_dentry_iput, 951 }; 952 953 /* 954 * Use intent information to determine whether we need to substitute 955 * the NFSv4-style stateful OPEN for the LOOKUP call 956 */ 957 static int is_atomic_open(struct inode *dir, struct nameidata *nd) 958 { 959 if (nd == NULL || nfs_lookup_check_intent(nd, LOOKUP_OPEN) == 0) 960 return 0; 961 /* NFS does not (yet) have a stateful open for directories */ 962 if (nd->flags & LOOKUP_DIRECTORY) 963 return 0; 964 /* Are we trying to write to a read only partition? */ 965 if (IS_RDONLY(dir) && (nd->intent.open.flags & (O_CREAT|O_TRUNC|FMODE_WRITE))) 966 return 0; 967 return 1; 968 } 969 970 static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) 971 { 972 struct dentry *res = NULL; 973 int error; 974 975 dfprintk(VFS, "NFS: atomic_lookup(%s/%ld), %s\n", 976 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 977 978 /* Check that we are indeed trying to open this file */ 979 if (!is_atomic_open(dir, nd)) 980 goto no_open; 981 982 if (dentry->d_name.len > NFS_SERVER(dir)->namelen) { 983 res = ERR_PTR(-ENAMETOOLONG); 984 goto out; 985 } 986 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 987 988 /* Let vfs_create() deal with O_EXCL. Instantiate, but don't hash 989 * the dentry. */ 990 if (nd->intent.open.flags & O_EXCL) { 991 d_instantiate(dentry, NULL); 992 goto out; 993 } 994 995 /* Open the file on the server */ 996 lock_kernel(); 997 res = nfs4_atomic_open(dir, dentry, nd); 998 unlock_kernel(); 999 if (IS_ERR(res)) { 1000 error = PTR_ERR(res); 1001 switch (error) { 1002 /* Make a negative dentry */ 1003 case -ENOENT: 1004 res = NULL; 1005 goto out; 1006 /* This turned out not to be a regular file */ 1007 case -EISDIR: 1008 case -ENOTDIR: 1009 goto no_open; 1010 case -ELOOP: 1011 if (!(nd->intent.open.flags & O_NOFOLLOW)) 1012 goto no_open; 1013 /* case -EINVAL: */ 1014 default: 1015 goto out; 1016 } 1017 } else if (res != NULL) 1018 dentry = res; 1019 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1020 out: 1021 return res; 1022 no_open: 1023 return nfs_lookup(dir, dentry, nd); 1024 } 1025 1026 static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd) 1027 { 1028 struct dentry *parent = NULL; 1029 struct inode *inode = dentry->d_inode; 1030 struct inode *dir; 1031 int openflags, ret = 0; 1032 1033 parent = dget_parent(dentry); 1034 dir = parent->d_inode; 1035 if (!is_atomic_open(dir, nd)) 1036 goto no_open; 1037 /* We can't create new files in nfs_open_revalidate(), so we 1038 * optimize away revalidation of negative dentries. 1039 */ 1040 if (inode == NULL) 1041 goto out; 1042 /* NFS only supports OPEN on regular files */ 1043 if (!S_ISREG(inode->i_mode)) 1044 goto no_open; 1045 openflags = nd->intent.open.flags; 1046 /* We cannot do exclusive creation on a positive dentry */ 1047 if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) 1048 goto no_open; 1049 /* We can't create new files, or truncate existing ones here */ 1050 openflags &= ~(O_CREAT|O_TRUNC); 1051 1052 /* 1053 * Note: we're not holding inode->i_mutex and so may be racing with 1054 * operations that change the directory. We therefore save the 1055 * change attribute *before* we do the RPC call. 1056 */ 1057 lock_kernel(); 1058 ret = nfs4_open_revalidate(dir, dentry, openflags, nd); 1059 if (ret == 1) 1060 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1061 unlock_kernel(); 1062 out: 1063 dput(parent); 1064 if (!ret) 1065 d_drop(dentry); 1066 return ret; 1067 no_open: 1068 dput(parent); 1069 if (inode != NULL && nfs_have_delegation(inode, FMODE_READ)) 1070 return 1; 1071 return nfs_lookup_revalidate(dentry, nd); 1072 } 1073 #endif /* CONFIG_NFSV4 */ 1074 1075 static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc) 1076 { 1077 struct dentry *parent = desc->file->f_path.dentry; 1078 struct inode *dir = parent->d_inode; 1079 struct nfs_entry *entry = desc->entry; 1080 struct dentry *dentry, *alias; 1081 struct qstr name = { 1082 .name = entry->name, 1083 .len = entry->len, 1084 }; 1085 struct inode *inode; 1086 unsigned long verf = nfs_save_change_attribute(dir); 1087 1088 switch (name.len) { 1089 case 2: 1090 if (name.name[0] == '.' && name.name[1] == '.') 1091 return dget_parent(parent); 1092 break; 1093 case 1: 1094 if (name.name[0] == '.') 1095 return dget(parent); 1096 } 1097 1098 spin_lock(&dir->i_lock); 1099 if (NFS_I(dir)->cache_validity & NFS_INO_INVALID_DATA) { 1100 spin_unlock(&dir->i_lock); 1101 return NULL; 1102 } 1103 spin_unlock(&dir->i_lock); 1104 1105 name.hash = full_name_hash(name.name, name.len); 1106 dentry = d_lookup(parent, &name); 1107 if (dentry != NULL) { 1108 /* Is this a positive dentry that matches the readdir info? */ 1109 if (dentry->d_inode != NULL && 1110 (NFS_FILEID(dentry->d_inode) == entry->ino || 1111 d_mountpoint(dentry))) { 1112 if (!desc->plus || entry->fh->size == 0) 1113 return dentry; 1114 if (nfs_compare_fh(NFS_FH(dentry->d_inode), 1115 entry->fh) == 0) 1116 goto out_renew; 1117 } 1118 /* No, so d_drop to allow one to be created */ 1119 d_drop(dentry); 1120 dput(dentry); 1121 } 1122 if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR)) 1123 return NULL; 1124 if (name.len > NFS_SERVER(dir)->namelen) 1125 return NULL; 1126 /* Note: caller is already holding the dir->i_mutex! */ 1127 dentry = d_alloc(parent, &name); 1128 if (dentry == NULL) 1129 return NULL; 1130 dentry->d_op = NFS_PROTO(dir)->dentry_ops; 1131 inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr); 1132 if (IS_ERR(inode)) { 1133 dput(dentry); 1134 return NULL; 1135 } 1136 1137 alias = d_materialise_unique(dentry, inode); 1138 if (alias != NULL) { 1139 dput(dentry); 1140 if (IS_ERR(alias)) 1141 return NULL; 1142 dentry = alias; 1143 } 1144 1145 out_renew: 1146 nfs_set_verifier(dentry, verf); 1147 return dentry; 1148 } 1149 1150 /* 1151 * Code common to create, mkdir, and mknod. 1152 */ 1153 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, 1154 struct nfs_fattr *fattr) 1155 { 1156 struct dentry *parent = dget_parent(dentry); 1157 struct inode *dir = parent->d_inode; 1158 struct inode *inode; 1159 int error = -EACCES; 1160 1161 d_drop(dentry); 1162 1163 /* We may have been initialized further down */ 1164 if (dentry->d_inode) 1165 goto out; 1166 if (fhandle->size == 0) { 1167 error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr); 1168 if (error) 1169 goto out_error; 1170 } 1171 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1172 if (!(fattr->valid & NFS_ATTR_FATTR)) { 1173 struct nfs_server *server = NFS_SB(dentry->d_sb); 1174 error = server->nfs_client->rpc_ops->getattr(server, fhandle, fattr); 1175 if (error < 0) 1176 goto out_error; 1177 } 1178 inode = nfs_fhget(dentry->d_sb, fhandle, fattr); 1179 error = PTR_ERR(inode); 1180 if (IS_ERR(inode)) 1181 goto out_error; 1182 d_add(dentry, inode); 1183 out: 1184 dput(parent); 1185 return 0; 1186 out_error: 1187 nfs_mark_for_revalidate(dir); 1188 dput(parent); 1189 return error; 1190 } 1191 1192 /* 1193 * Following a failed create operation, we drop the dentry rather 1194 * than retain a negative dentry. This avoids a problem in the event 1195 * that the operation succeeded on the server, but an error in the 1196 * reply path made it appear to have failed. 1197 */ 1198 static int nfs_create(struct inode *dir, struct dentry *dentry, int mode, 1199 struct nameidata *nd) 1200 { 1201 struct iattr attr; 1202 int error; 1203 int open_flags = 0; 1204 1205 dfprintk(VFS, "NFS: create(%s/%ld), %s\n", 1206 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1207 1208 attr.ia_mode = mode; 1209 attr.ia_valid = ATTR_MODE; 1210 1211 if ((nd->flags & LOOKUP_CREATE) != 0) 1212 open_flags = nd->intent.open.flags; 1213 1214 lock_kernel(); 1215 error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags, nd); 1216 if (error != 0) 1217 goto out_err; 1218 unlock_kernel(); 1219 return 0; 1220 out_err: 1221 unlock_kernel(); 1222 d_drop(dentry); 1223 return error; 1224 } 1225 1226 /* 1227 * See comments for nfs_proc_create regarding failed operations. 1228 */ 1229 static int 1230 nfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev) 1231 { 1232 struct iattr attr; 1233 int status; 1234 1235 dfprintk(VFS, "NFS: mknod(%s/%ld), %s\n", 1236 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1237 1238 if (!new_valid_dev(rdev)) 1239 return -EINVAL; 1240 1241 attr.ia_mode = mode; 1242 attr.ia_valid = ATTR_MODE; 1243 1244 lock_kernel(); 1245 status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev); 1246 if (status != 0) 1247 goto out_err; 1248 unlock_kernel(); 1249 return 0; 1250 out_err: 1251 unlock_kernel(); 1252 d_drop(dentry); 1253 return status; 1254 } 1255 1256 /* 1257 * See comments for nfs_proc_create regarding failed operations. 1258 */ 1259 static int nfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 1260 { 1261 struct iattr attr; 1262 int error; 1263 1264 dfprintk(VFS, "NFS: mkdir(%s/%ld), %s\n", 1265 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1266 1267 attr.ia_valid = ATTR_MODE; 1268 attr.ia_mode = mode | S_IFDIR; 1269 1270 lock_kernel(); 1271 error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr); 1272 if (error != 0) 1273 goto out_err; 1274 unlock_kernel(); 1275 return 0; 1276 out_err: 1277 d_drop(dentry); 1278 unlock_kernel(); 1279 return error; 1280 } 1281 1282 static int nfs_rmdir(struct inode *dir, struct dentry *dentry) 1283 { 1284 int error; 1285 1286 dfprintk(VFS, "NFS: rmdir(%s/%ld), %s\n", 1287 dir->i_sb->s_id, dir->i_ino, dentry->d_name.name); 1288 1289 lock_kernel(); 1290 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name); 1291 /* Ensure the VFS deletes this inode */ 1292 if (error == 0 && dentry->d_inode != NULL) 1293 clear_nlink(dentry->d_inode); 1294 unlock_kernel(); 1295 1296 return error; 1297 } 1298 1299 static int nfs_sillyrename(struct inode *dir, struct dentry *dentry) 1300 { 1301 static unsigned int sillycounter; 1302 const int fileidsize = sizeof(NFS_FILEID(dentry->d_inode))*2; 1303 const int countersize = sizeof(sillycounter)*2; 1304 const int slen = sizeof(".nfs")+fileidsize+countersize-1; 1305 char silly[slen+1]; 1306 struct qstr qsilly; 1307 struct dentry *sdentry; 1308 int error = -EIO; 1309 1310 dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n", 1311 dentry->d_parent->d_name.name, dentry->d_name.name, 1312 atomic_read(&dentry->d_count)); 1313 nfs_inc_stats(dir, NFSIOS_SILLYRENAME); 1314 1315 /* 1316 * We don't allow a dentry to be silly-renamed twice. 1317 */ 1318 error = -EBUSY; 1319 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 1320 goto out; 1321 1322 sprintf(silly, ".nfs%*.*Lx", 1323 fileidsize, fileidsize, 1324 (unsigned long long)NFS_FILEID(dentry->d_inode)); 1325 1326 /* Return delegation in anticipation of the rename */ 1327 nfs_inode_return_delegation(dentry->d_inode); 1328 1329 sdentry = NULL; 1330 do { 1331 char *suffix = silly + slen - countersize; 1332 1333 dput(sdentry); 1334 sillycounter++; 1335 sprintf(suffix, "%*.*x", countersize, countersize, sillycounter); 1336 1337 dfprintk(VFS, "NFS: trying to rename %s to %s\n", 1338 dentry->d_name.name, silly); 1339 1340 sdentry = lookup_one_len(silly, dentry->d_parent, slen); 1341 /* 1342 * N.B. Better to return EBUSY here ... it could be 1343 * dangerous to delete the file while it's in use. 1344 */ 1345 if (IS_ERR(sdentry)) 1346 goto out; 1347 } while(sdentry->d_inode != NULL); /* need negative lookup */ 1348 1349 qsilly.name = silly; 1350 qsilly.len = strlen(silly); 1351 if (dentry->d_inode) { 1352 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, 1353 dir, &qsilly); 1354 nfs_mark_for_revalidate(dentry->d_inode); 1355 } else 1356 error = NFS_PROTO(dir)->rename(dir, &dentry->d_name, 1357 dir, &qsilly); 1358 if (!error) { 1359 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1360 d_move(dentry, sdentry); 1361 error = nfs_async_unlink(dir, dentry); 1362 /* If we return 0 we don't unlink */ 1363 } 1364 dput(sdentry); 1365 out: 1366 return error; 1367 } 1368 1369 /* 1370 * Remove a file after making sure there are no pending writes, 1371 * and after checking that the file has only one user. 1372 * 1373 * We invalidate the attribute cache and free the inode prior to the operation 1374 * to avoid possible races if the server reuses the inode. 1375 */ 1376 static int nfs_safe_remove(struct dentry *dentry) 1377 { 1378 struct inode *dir = dentry->d_parent->d_inode; 1379 struct inode *inode = dentry->d_inode; 1380 int error = -EBUSY; 1381 1382 dfprintk(VFS, "NFS: safe_remove(%s/%s)\n", 1383 dentry->d_parent->d_name.name, dentry->d_name.name); 1384 1385 /* If the dentry was sillyrenamed, we simply call d_delete() */ 1386 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 1387 error = 0; 1388 goto out; 1389 } 1390 1391 if (inode != NULL) { 1392 nfs_inode_return_delegation(inode); 1393 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1394 /* The VFS may want to delete this inode */ 1395 if (error == 0) 1396 drop_nlink(inode); 1397 nfs_mark_for_revalidate(inode); 1398 } else 1399 error = NFS_PROTO(dir)->remove(dir, &dentry->d_name); 1400 out: 1401 return error; 1402 } 1403 1404 /* We do silly rename. In case sillyrename() returns -EBUSY, the inode 1405 * belongs to an active ".nfs..." file and we return -EBUSY. 1406 * 1407 * If sillyrename() returns 0, we do nothing, otherwise we unlink. 1408 */ 1409 static int nfs_unlink(struct inode *dir, struct dentry *dentry) 1410 { 1411 int error; 1412 int need_rehash = 0; 1413 1414 dfprintk(VFS, "NFS: unlink(%s/%ld, %s)\n", dir->i_sb->s_id, 1415 dir->i_ino, dentry->d_name.name); 1416 1417 lock_kernel(); 1418 spin_lock(&dcache_lock); 1419 spin_lock(&dentry->d_lock); 1420 if (atomic_read(&dentry->d_count) > 1) { 1421 spin_unlock(&dentry->d_lock); 1422 spin_unlock(&dcache_lock); 1423 /* Start asynchronous writeout of the inode */ 1424 write_inode_now(dentry->d_inode, 0); 1425 error = nfs_sillyrename(dir, dentry); 1426 unlock_kernel(); 1427 return error; 1428 } 1429 if (!d_unhashed(dentry)) { 1430 __d_drop(dentry); 1431 need_rehash = 1; 1432 } 1433 spin_unlock(&dentry->d_lock); 1434 spin_unlock(&dcache_lock); 1435 error = nfs_safe_remove(dentry); 1436 if (!error) { 1437 nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); 1438 } else if (need_rehash) 1439 d_rehash(dentry); 1440 unlock_kernel(); 1441 return error; 1442 } 1443 1444 /* 1445 * To create a symbolic link, most file systems instantiate a new inode, 1446 * add a page to it containing the path, then write it out to the disk 1447 * using prepare_write/commit_write. 1448 * 1449 * Unfortunately the NFS client can't create the in-core inode first 1450 * because it needs a file handle to create an in-core inode (see 1451 * fs/nfs/inode.c:nfs_fhget). We only have a file handle *after* the 1452 * symlink request has completed on the server. 1453 * 1454 * So instead we allocate a raw page, copy the symname into it, then do 1455 * the SYMLINK request with the page as the buffer. If it succeeds, we 1456 * now have a new file handle and can instantiate an in-core NFS inode 1457 * and move the raw page into its mapping. 1458 */ 1459 static int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) 1460 { 1461 struct pagevec lru_pvec; 1462 struct page *page; 1463 char *kaddr; 1464 struct iattr attr; 1465 unsigned int pathlen = strlen(symname); 1466 int error; 1467 1468 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id, 1469 dir->i_ino, dentry->d_name.name, symname); 1470 1471 if (pathlen > PAGE_SIZE) 1472 return -ENAMETOOLONG; 1473 1474 attr.ia_mode = S_IFLNK | S_IRWXUGO; 1475 attr.ia_valid = ATTR_MODE; 1476 1477 lock_kernel(); 1478 1479 page = alloc_page(GFP_HIGHUSER); 1480 if (!page) { 1481 unlock_kernel(); 1482 return -ENOMEM; 1483 } 1484 1485 kaddr = kmap_atomic(page, KM_USER0); 1486 memcpy(kaddr, symname, pathlen); 1487 if (pathlen < PAGE_SIZE) 1488 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen); 1489 kunmap_atomic(kaddr, KM_USER0); 1490 1491 error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr); 1492 if (error != 0) { 1493 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s) error %d\n", 1494 dir->i_sb->s_id, dir->i_ino, 1495 dentry->d_name.name, symname, error); 1496 d_drop(dentry); 1497 __free_page(page); 1498 unlock_kernel(); 1499 return error; 1500 } 1501 1502 /* 1503 * No big deal if we can't add this page to the page cache here. 1504 * READLINK will get the missing page from the server if needed. 1505 */ 1506 pagevec_init(&lru_pvec, 0); 1507 if (!add_to_page_cache(page, dentry->d_inode->i_mapping, 0, 1508 GFP_KERNEL)) { 1509 pagevec_add(&lru_pvec, page); 1510 pagevec_lru_add(&lru_pvec); 1511 SetPageUptodate(page); 1512 unlock_page(page); 1513 } else 1514 __free_page(page); 1515 1516 unlock_kernel(); 1517 return 0; 1518 } 1519 1520 static int 1521 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 1522 { 1523 struct inode *inode = old_dentry->d_inode; 1524 int error; 1525 1526 dfprintk(VFS, "NFS: link(%s/%s -> %s/%s)\n", 1527 old_dentry->d_parent->d_name.name, old_dentry->d_name.name, 1528 dentry->d_parent->d_name.name, dentry->d_name.name); 1529 1530 lock_kernel(); 1531 error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); 1532 if (error == 0) { 1533 atomic_inc(&inode->i_count); 1534 d_instantiate(dentry, inode); 1535 } 1536 unlock_kernel(); 1537 return error; 1538 } 1539 1540 /* 1541 * RENAME 1542 * FIXME: Some nfsds, like the Linux user space nfsd, may generate a 1543 * different file handle for the same inode after a rename (e.g. when 1544 * moving to a different directory). A fail-safe method to do so would 1545 * be to look up old_dir/old_name, create a link to new_dir/new_name and 1546 * rename the old file using the sillyrename stuff. This way, the original 1547 * file in old_dir will go away when the last process iput()s the inode. 1548 * 1549 * FIXED. 1550 * 1551 * It actually works quite well. One needs to have the possibility for 1552 * at least one ".nfs..." file in each directory the file ever gets 1553 * moved or linked to which happens automagically with the new 1554 * implementation that only depends on the dcache stuff instead of 1555 * using the inode layer 1556 * 1557 * Unfortunately, things are a little more complicated than indicated 1558 * above. For a cross-directory move, we want to make sure we can get 1559 * rid of the old inode after the operation. This means there must be 1560 * no pending writes (if it's a file), and the use count must be 1. 1561 * If these conditions are met, we can drop the dentries before doing 1562 * the rename. 1563 */ 1564 static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry, 1565 struct inode *new_dir, struct dentry *new_dentry) 1566 { 1567 struct inode *old_inode = old_dentry->d_inode; 1568 struct inode *new_inode = new_dentry->d_inode; 1569 struct dentry *dentry = NULL, *rehash = NULL; 1570 int error = -EBUSY; 1571 1572 /* 1573 * To prevent any new references to the target during the rename, 1574 * we unhash the dentry and free the inode in advance. 1575 */ 1576 lock_kernel(); 1577 if (!d_unhashed(new_dentry)) { 1578 d_drop(new_dentry); 1579 rehash = new_dentry; 1580 } 1581 1582 dfprintk(VFS, "NFS: rename(%s/%s -> %s/%s, ct=%d)\n", 1583 old_dentry->d_parent->d_name.name, old_dentry->d_name.name, 1584 new_dentry->d_parent->d_name.name, new_dentry->d_name.name, 1585 atomic_read(&new_dentry->d_count)); 1586 1587 /* 1588 * First check whether the target is busy ... we can't 1589 * safely do _any_ rename if the target is in use. 1590 * 1591 * For files, make a copy of the dentry and then do a 1592 * silly-rename. If the silly-rename succeeds, the 1593 * copied dentry is hashed and becomes the new target. 1594 */ 1595 if (!new_inode) 1596 goto go_ahead; 1597 if (S_ISDIR(new_inode->i_mode)) { 1598 error = -EISDIR; 1599 if (!S_ISDIR(old_inode->i_mode)) 1600 goto out; 1601 } else if (atomic_read(&new_dentry->d_count) > 2) { 1602 int err; 1603 /* copy the target dentry's name */ 1604 dentry = d_alloc(new_dentry->d_parent, 1605 &new_dentry->d_name); 1606 if (!dentry) 1607 goto out; 1608 1609 /* silly-rename the existing target ... */ 1610 err = nfs_sillyrename(new_dir, new_dentry); 1611 if (!err) { 1612 new_dentry = rehash = dentry; 1613 new_inode = NULL; 1614 /* instantiate the replacement target */ 1615 d_instantiate(new_dentry, NULL); 1616 } else if (atomic_read(&new_dentry->d_count) > 1) 1617 /* dentry still busy? */ 1618 goto out; 1619 } else 1620 drop_nlink(new_inode); 1621 1622 go_ahead: 1623 /* 1624 * ... prune child dentries and writebacks if needed. 1625 */ 1626 if (atomic_read(&old_dentry->d_count) > 1) { 1627 if (S_ISREG(old_inode->i_mode)) 1628 nfs_wb_all(old_inode); 1629 shrink_dcache_parent(old_dentry); 1630 } 1631 nfs_inode_return_delegation(old_inode); 1632 1633 if (new_inode != NULL) { 1634 nfs_inode_return_delegation(new_inode); 1635 d_delete(new_dentry); 1636 } 1637 1638 error = NFS_PROTO(old_dir)->rename(old_dir, &old_dentry->d_name, 1639 new_dir, &new_dentry->d_name); 1640 nfs_mark_for_revalidate(old_inode); 1641 out: 1642 if (rehash) 1643 d_rehash(rehash); 1644 if (!error) { 1645 d_move(old_dentry, new_dentry); 1646 nfs_set_verifier(new_dentry, 1647 nfs_save_change_attribute(new_dir)); 1648 } 1649 1650 /* new dentry created? */ 1651 if (dentry) 1652 dput(dentry); 1653 unlock_kernel(); 1654 return error; 1655 } 1656 1657 static DEFINE_SPINLOCK(nfs_access_lru_lock); 1658 static LIST_HEAD(nfs_access_lru_list); 1659 static atomic_long_t nfs_access_nr_entries; 1660 1661 static void nfs_access_free_entry(struct nfs_access_entry *entry) 1662 { 1663 put_rpccred(entry->cred); 1664 kfree(entry); 1665 smp_mb__before_atomic_dec(); 1666 atomic_long_dec(&nfs_access_nr_entries); 1667 smp_mb__after_atomic_dec(); 1668 } 1669 1670 int nfs_access_cache_shrinker(int nr_to_scan, gfp_t gfp_mask) 1671 { 1672 LIST_HEAD(head); 1673 struct nfs_inode *nfsi; 1674 struct nfs_access_entry *cache; 1675 1676 restart: 1677 spin_lock(&nfs_access_lru_lock); 1678 list_for_each_entry(nfsi, &nfs_access_lru_list, access_cache_inode_lru) { 1679 struct inode *inode; 1680 1681 if (nr_to_scan-- == 0) 1682 break; 1683 inode = igrab(&nfsi->vfs_inode); 1684 if (inode == NULL) 1685 continue; 1686 spin_lock(&inode->i_lock); 1687 if (list_empty(&nfsi->access_cache_entry_lru)) 1688 goto remove_lru_entry; 1689 cache = list_entry(nfsi->access_cache_entry_lru.next, 1690 struct nfs_access_entry, lru); 1691 list_move(&cache->lru, &head); 1692 rb_erase(&cache->rb_node, &nfsi->access_cache); 1693 if (!list_empty(&nfsi->access_cache_entry_lru)) 1694 list_move_tail(&nfsi->access_cache_inode_lru, 1695 &nfs_access_lru_list); 1696 else { 1697 remove_lru_entry: 1698 list_del_init(&nfsi->access_cache_inode_lru); 1699 clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags); 1700 } 1701 spin_unlock(&inode->i_lock); 1702 spin_unlock(&nfs_access_lru_lock); 1703 iput(inode); 1704 goto restart; 1705 } 1706 spin_unlock(&nfs_access_lru_lock); 1707 while (!list_empty(&head)) { 1708 cache = list_entry(head.next, struct nfs_access_entry, lru); 1709 list_del(&cache->lru); 1710 nfs_access_free_entry(cache); 1711 } 1712 return (atomic_long_read(&nfs_access_nr_entries) / 100) * sysctl_vfs_cache_pressure; 1713 } 1714 1715 static void __nfs_access_zap_cache(struct inode *inode) 1716 { 1717 struct nfs_inode *nfsi = NFS_I(inode); 1718 struct rb_root *root_node = &nfsi->access_cache; 1719 struct rb_node *n, *dispose = NULL; 1720 struct nfs_access_entry *entry; 1721 1722 /* Unhook entries from the cache */ 1723 while ((n = rb_first(root_node)) != NULL) { 1724 entry = rb_entry(n, struct nfs_access_entry, rb_node); 1725 rb_erase(n, root_node); 1726 list_del(&entry->lru); 1727 n->rb_left = dispose; 1728 dispose = n; 1729 } 1730 nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; 1731 spin_unlock(&inode->i_lock); 1732 1733 /* Now kill them all! */ 1734 while (dispose != NULL) { 1735 n = dispose; 1736 dispose = n->rb_left; 1737 nfs_access_free_entry(rb_entry(n, struct nfs_access_entry, rb_node)); 1738 } 1739 } 1740 1741 void nfs_access_zap_cache(struct inode *inode) 1742 { 1743 /* Remove from global LRU init */ 1744 if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) { 1745 spin_lock(&nfs_access_lru_lock); 1746 list_del_init(&NFS_I(inode)->access_cache_inode_lru); 1747 spin_unlock(&nfs_access_lru_lock); 1748 } 1749 1750 spin_lock(&inode->i_lock); 1751 /* This will release the spinlock */ 1752 __nfs_access_zap_cache(inode); 1753 } 1754 1755 static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred) 1756 { 1757 struct rb_node *n = NFS_I(inode)->access_cache.rb_node; 1758 struct nfs_access_entry *entry; 1759 1760 while (n != NULL) { 1761 entry = rb_entry(n, struct nfs_access_entry, rb_node); 1762 1763 if (cred < entry->cred) 1764 n = n->rb_left; 1765 else if (cred > entry->cred) 1766 n = n->rb_right; 1767 else 1768 return entry; 1769 } 1770 return NULL; 1771 } 1772 1773 static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) 1774 { 1775 struct nfs_inode *nfsi = NFS_I(inode); 1776 struct nfs_access_entry *cache; 1777 int err = -ENOENT; 1778 1779 spin_lock(&inode->i_lock); 1780 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) 1781 goto out_zap; 1782 cache = nfs_access_search_rbtree(inode, cred); 1783 if (cache == NULL) 1784 goto out; 1785 if (!time_in_range(jiffies, cache->jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))) 1786 goto out_stale; 1787 res->jiffies = cache->jiffies; 1788 res->cred = cache->cred; 1789 res->mask = cache->mask; 1790 list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru); 1791 err = 0; 1792 out: 1793 spin_unlock(&inode->i_lock); 1794 return err; 1795 out_stale: 1796 rb_erase(&cache->rb_node, &nfsi->access_cache); 1797 list_del(&cache->lru); 1798 spin_unlock(&inode->i_lock); 1799 nfs_access_free_entry(cache); 1800 return -ENOENT; 1801 out_zap: 1802 /* This will release the spinlock */ 1803 __nfs_access_zap_cache(inode); 1804 return -ENOENT; 1805 } 1806 1807 static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) 1808 { 1809 struct nfs_inode *nfsi = NFS_I(inode); 1810 struct rb_root *root_node = &nfsi->access_cache; 1811 struct rb_node **p = &root_node->rb_node; 1812 struct rb_node *parent = NULL; 1813 struct nfs_access_entry *entry; 1814 1815 spin_lock(&inode->i_lock); 1816 while (*p != NULL) { 1817 parent = *p; 1818 entry = rb_entry(parent, struct nfs_access_entry, rb_node); 1819 1820 if (set->cred < entry->cred) 1821 p = &parent->rb_left; 1822 else if (set->cred > entry->cred) 1823 p = &parent->rb_right; 1824 else 1825 goto found; 1826 } 1827 rb_link_node(&set->rb_node, parent, p); 1828 rb_insert_color(&set->rb_node, root_node); 1829 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 1830 spin_unlock(&inode->i_lock); 1831 return; 1832 found: 1833 rb_replace_node(parent, &set->rb_node, root_node); 1834 list_add_tail(&set->lru, &nfsi->access_cache_entry_lru); 1835 list_del(&entry->lru); 1836 spin_unlock(&inode->i_lock); 1837 nfs_access_free_entry(entry); 1838 } 1839 1840 static void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) 1841 { 1842 struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); 1843 if (cache == NULL) 1844 return; 1845 RB_CLEAR_NODE(&cache->rb_node); 1846 cache->jiffies = set->jiffies; 1847 cache->cred = get_rpccred(set->cred); 1848 cache->mask = set->mask; 1849 1850 nfs_access_add_rbtree(inode, cache); 1851 1852 /* Update accounting */ 1853 smp_mb__before_atomic_inc(); 1854 atomic_long_inc(&nfs_access_nr_entries); 1855 smp_mb__after_atomic_inc(); 1856 1857 /* Add inode to global LRU list */ 1858 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_FLAGS(inode))) { 1859 spin_lock(&nfs_access_lru_lock); 1860 list_add_tail(&NFS_I(inode)->access_cache_inode_lru, &nfs_access_lru_list); 1861 spin_unlock(&nfs_access_lru_lock); 1862 } 1863 } 1864 1865 static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) 1866 { 1867 struct nfs_access_entry cache; 1868 int status; 1869 1870 status = nfs_access_get_cached(inode, cred, &cache); 1871 if (status == 0) 1872 goto out; 1873 1874 /* Be clever: ask server to check for all possible rights */ 1875 cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ; 1876 cache.cred = cred; 1877 cache.jiffies = jiffies; 1878 status = NFS_PROTO(inode)->access(inode, &cache); 1879 if (status != 0) 1880 return status; 1881 nfs_access_add_cache(inode, &cache); 1882 out: 1883 if ((cache.mask & mask) == mask) 1884 return 0; 1885 return -EACCES; 1886 } 1887 1888 static int nfs_open_permission_mask(int openflags) 1889 { 1890 int mask = 0; 1891 1892 if (openflags & FMODE_READ) 1893 mask |= MAY_READ; 1894 if (openflags & FMODE_WRITE) 1895 mask |= MAY_WRITE; 1896 if (openflags & FMODE_EXEC) 1897 mask |= MAY_EXEC; 1898 return mask; 1899 } 1900 1901 int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags) 1902 { 1903 return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags)); 1904 } 1905 1906 int nfs_permission(struct inode *inode, int mask, struct nameidata *nd) 1907 { 1908 struct rpc_cred *cred; 1909 int res = 0; 1910 1911 nfs_inc_stats(inode, NFSIOS_VFSACCESS); 1912 1913 if (mask == 0) 1914 goto out; 1915 /* Is this sys_access() ? */ 1916 if (nd != NULL && (nd->flags & LOOKUP_ACCESS)) 1917 goto force_lookup; 1918 1919 switch (inode->i_mode & S_IFMT) { 1920 case S_IFLNK: 1921 goto out; 1922 case S_IFREG: 1923 /* NFSv4 has atomic_open... */ 1924 if (nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN) 1925 && nd != NULL 1926 && (nd->flags & LOOKUP_OPEN)) 1927 goto out; 1928 break; 1929 case S_IFDIR: 1930 /* 1931 * Optimize away all write operations, since the server 1932 * will check permissions when we perform the op. 1933 */ 1934 if ((mask & MAY_WRITE) && !(mask & MAY_READ)) 1935 goto out; 1936 } 1937 1938 force_lookup: 1939 lock_kernel(); 1940 1941 if (!NFS_PROTO(inode)->access) 1942 goto out_notsup; 1943 1944 cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0); 1945 if (!IS_ERR(cred)) { 1946 res = nfs_do_access(inode, cred, mask); 1947 put_rpccred(cred); 1948 } else 1949 res = PTR_ERR(cred); 1950 unlock_kernel(); 1951 out: 1952 dfprintk(VFS, "NFS: permission(%s/%ld), mask=0x%x, res=%d\n", 1953 inode->i_sb->s_id, inode->i_ino, mask, res); 1954 return res; 1955 out_notsup: 1956 res = nfs_revalidate_inode(NFS_SERVER(inode), inode); 1957 if (res == 0) 1958 res = generic_permission(inode, mask, NULL); 1959 unlock_kernel(); 1960 goto out; 1961 } 1962 1963 /* 1964 * Local variables: 1965 * version-control: t 1966 * kept-new-versions: 5 1967 * End: 1968 */ 1969