fs/nfs/dir.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/nfs/dir.c
   4  *
   5  *  Copyright (C) 1992  Rick Sladkey
   6  *
   7  *  nfs directory handling functions
   8  *
   9  * 10 Apr 1996  Added silly rename for unlink   --okir
  10  * 28 Sep 1996  Improved directory cache --okir
  11  * 23 Aug 1997  Claus Heine claus@momo.math.rwth-aachen.de
  12  *              Re-implemented silly rename for unlink, newly implemented
  13  *              silly rename for nfs_rename() following the suggestions
  14  *              of Olaf Kirch (okir) found in this file.
  15  *              Following Linus comments on my original hack, this version
  16  *              depends only on the dcache stuff and doesn't touch the inode
  17  *              layer (iput() and friends).
  18  *  6 Jun 1999  Cache readdir lookups in the page cache. -DaveM
  19  */
  20
  21 #include <linux/compat.h>
  22 #include <linux/module.h>
  23 #include <linux/time.h>
  24 #include <linux/errno.h>
  25 #include <linux/stat.h>
  26 #include <linux/fcntl.h>
  27 #include <linux/string.h>
  28 #include <linux/kernel.h>
  29 #include <linux/slab.h>
  30 #include <linux/mm.h>
  31 #include <linux/sunrpc/clnt.h>
  32 #include <linux/nfs_fs.h>
  33 #include <linux/nfs_mount.h>
  34 #include <linux/pagemap.h>
  35 #include <linux/pagevec.h>
  36 #include <linux/namei.h>
  37 #include <linux/mount.h>
  38 #include <linux/swap.h>
  39 #include <linux/sched.h>
  40 #include <linux/kmemleak.h>
  41 #include <linux/xattr.h>
  42 #include <linux/xxhash.h>
  43
  44 #include "delegation.h"
  45 #include "iostat.h"
  46 #include "internal.h"
  47 #include "fscache.h"
  48
  49 #include "nfstrace.h"
  50
  51 /* #define NFS_DEBUG_VERBOSE 1 */
  52
  53 static int nfs_opendir(struct inode *, struct file *);
  54 static int nfs_closedir(struct inode *, struct file *);
  55 static int nfs_readdir(struct file *, struct dir_context *);
  56 static int nfs_fsync_dir(struct file *, loff_t, loff_t, int);
  57 static loff_t nfs_llseek_dir(struct file *, loff_t, int);
  58 static void nfs_readdir_clear_array(struct page*);
  59
  60 const struct file_operations nfs_dir_operations = {
  61         .llseek         = nfs_llseek_dir,
  62         .read           = generic_read_dir,
  63         .iterate_shared = nfs_readdir,
  64         .open           = nfs_opendir,
  65         .release        = nfs_closedir,
  66         .fsync          = nfs_fsync_dir,
  67 };
  68
  69 const struct address_space_operations nfs_dir_aops = {
  70         .freepage = nfs_readdir_clear_array,
  71 };
  72
  73 #define NFS_INIT_DTSIZE PAGE_SIZE
  74
  75 static struct nfs_open_dir_context *
  76 alloc_nfs_open_dir_context(struct inode *dir)
  77 {
  78         struct nfs_inode *nfsi = NFS_I(dir);
  79         struct nfs_open_dir_context *ctx;
  80
  81         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
  82         if (ctx != NULL) {
  83                 ctx->attr_gencount = nfsi->attr_gencount;
  84                 ctx->dtsize = NFS_INIT_DTSIZE;
  85                 spin_lock(&dir->i_lock);
  86                 if (list_empty(&nfsi->open_files) &&
  87                     (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER))
  88                         nfs_set_cache_invalid(dir,
  89                                               NFS_INO_INVALID_DATA |
  90                                                       NFS_INO_REVAL_FORCED);
  91                 list_add_tail_rcu(&ctx->list, &nfsi->open_files);
  92                 memcpy(ctx->verf, nfsi->cookieverf, sizeof(ctx->verf));
  93                 spin_unlock(&dir->i_lock);
  94                 return ctx;
  95         }
  96         return  ERR_PTR(-ENOMEM);
  97 }
  98
  99 static void put_nfs_open_dir_context(struct inode *dir, struct nfs_open_dir_context *ctx)
 100 {
 101         spin_lock(&dir->i_lock);
 102         list_del_rcu(&ctx->list);
 103         spin_unlock(&dir->i_lock);
 104         kfree_rcu(ctx, rcu_head);
 105 }
 106
 107 /*
 108  * Open file
 109  */
 110 static int
 111 nfs_opendir(struct inode *inode, struct file *filp)
 112 {
 113         int res = 0;
 114         struct nfs_open_dir_context *ctx;
 115
 116         dfprintk(FILE, "NFS: open dir(%pD2)\n", filp);
 117
 118         nfs_inc_stats(inode, NFSIOS_VFSOPEN);
 119
 120         ctx = alloc_nfs_open_dir_context(inode);
 121         if (IS_ERR(ctx)) {
 122                 res = PTR_ERR(ctx);
 123                 goto out;
 124         }
 125         filp->private_data = ctx;
 126 out:
 127         return res;
 128 }
 129
 130 static int
 131 nfs_closedir(struct inode *inode, struct file *filp)
 132 {
 133         put_nfs_open_dir_context(file_inode(filp), filp->private_data);
 134         return 0;
 135 }
 136
 137 struct nfs_cache_array_entry {
 138         u64 cookie;
 139         u64 ino;
 140         const char *name;
 141         unsigned int name_len;
 142         unsigned char d_type;
 143 };
 144
 145 struct nfs_cache_array {
 146         u64 change_attr;
 147         u64 last_cookie;
 148         unsigned int size;
 149         unsigned char page_full : 1,
 150                       page_is_eof : 1,
 151                       cookies_are_ordered : 1;
 152         struct nfs_cache_array_entry array[];
 153 };
 154
 155 struct nfs_readdir_descriptor {
 156         struct file     *file;
 157         struct page     *page;
 158         struct dir_context *ctx;
 159         pgoff_t         page_index;
 160         pgoff_t         page_index_max;
 161         u64             dir_cookie;
 162         u64             last_cookie;
 163         loff_t          current_index;
 164
 165         __be32          verf[NFS_DIR_VERIFIER_SIZE];
 166         unsigned long   dir_verifier;
 167         unsigned long   timestamp;
 168         unsigned long   gencount;
 169         unsigned long   attr_gencount;
 170         unsigned int    cache_entry_index;
 171         unsigned int    buffer_fills;
 172         unsigned int    dtsize;
 173         bool clear_cache;
 174         bool plus;
 175         bool eob;
 176         bool eof;
 177 };
 178
 179 static void nfs_set_dtsize(struct nfs_readdir_descriptor *desc, unsigned int sz)
 180 {
 181         struct nfs_server *server = NFS_SERVER(file_inode(desc->file));
 182         unsigned int maxsize = server->dtsize;
 183
 184         if (sz > maxsize)
 185                 sz = maxsize;
 186         if (sz < NFS_MIN_FILE_IO_SIZE)
 187                 sz = NFS_MIN_FILE_IO_SIZE;
 188         desc->dtsize = sz;
 189 }
 190
 191 static void nfs_shrink_dtsize(struct nfs_readdir_descriptor *desc)
 192 {
 193         nfs_set_dtsize(desc, desc->dtsize >> 1);
 194 }
 195
 196 static void nfs_grow_dtsize(struct nfs_readdir_descriptor *desc)
 197 {
 198         nfs_set_dtsize(desc, desc->dtsize << 1);
 199 }
 200
 201 static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie,
 202                                         u64 change_attr)
 203 {
 204         struct nfs_cache_array *array;
 205
 206         array = kmap_atomic(page);
 207         array->change_attr = change_attr;
 208         array->last_cookie = last_cookie;
 209         array->size = 0;
 210         array->page_full = 0;
 211         array->page_is_eof = 0;
 212         array->cookies_are_ordered = 1;
 213         kunmap_atomic(array);
 214 }
 215
 216 /*
 217  * we are freeing strings created by nfs_add_to_readdir_array()
 218  */
 219 static void nfs_readdir_clear_array(struct page *page)
 220 {
 221         struct nfs_cache_array *array;
 222         unsigned int i;
 223
 224         array = kmap_atomic(page);
 225         for (i = 0; i < array->size; i++)
 226                 kfree(array->array[i].name);
 227         array->size = 0;
 228         kunmap_atomic(array);
 229 }
 230
 231 static void nfs_readdir_page_reinit_array(struct page *page, u64 last_cookie,
 232                                           u64 change_attr)
 233 {
 234         nfs_readdir_clear_array(page);
 235         nfs_readdir_page_init_array(page, last_cookie, change_attr);
 236 }
 237
 238 static struct page *
 239 nfs_readdir_page_array_alloc(u64 last_cookie, gfp_t gfp_flags)
 240 {
 241         struct page *page = alloc_page(gfp_flags);
 242         if (page)
 243                 nfs_readdir_page_init_array(page, last_cookie, 0);
 244         return page;
 245 }
 246
 247 static void nfs_readdir_page_array_free(struct page *page)
 248 {
 249         if (page) {
 250                 nfs_readdir_clear_array(page);
 251                 put_page(page);
 252         }
 253 }
 254
 255 static u64 nfs_readdir_array_index_cookie(struct nfs_cache_array *array)
 256 {
 257         return array->size == 0 ? array->last_cookie : array->array[0].cookie;
 258 }
 259
 260 static void nfs_readdir_array_set_eof(struct nfs_cache_array *array)
 261 {
 262         array->page_is_eof = 1;
 263         array->page_full = 1;
 264 }
 265
 266 static bool nfs_readdir_array_is_full(struct nfs_cache_array *array)
 267 {
 268         return array->page_full;
 269 }
 270
 271 /*
 272  * the caller is responsible for freeing qstr.name
 273  * when called by nfs_readdir_add_to_array, the strings will be freed in
 274  * nfs_clear_readdir_array()
 275  */
 276 static const char *nfs_readdir_copy_name(const char *name, unsigned int len)
 277 {
 278         const char *ret = kmemdup_nul(name, len, GFP_KERNEL);
 279
 280         /*
 281          * Avoid a kmemleak false positive. The pointer to the name is stored
 282          * in a page cache page which kmemleak does not scan.
 283          */
 284         if (ret != NULL)
 285                 kmemleak_not_leak(ret);
 286         return ret;
 287 }
 288
 289 static size_t nfs_readdir_array_maxentries(void)
 290 {
 291         return (PAGE_SIZE - sizeof(struct nfs_cache_array)) /
 292                sizeof(struct nfs_cache_array_entry);
 293 }
 294
 295 /*
 296  * Check that the next array entry lies entirely within the page bounds
 297  */
 298 static int nfs_readdir_array_can_expand(struct nfs_cache_array *array)
 299 {
 300         if (array->page_full)
 301                 return -ENOSPC;
 302         if (array->size == nfs_readdir_array_maxentries()) {
 303                 array->page_full = 1;
 304                 return -ENOSPC;
 305         }
 306         return 0;
 307 }
 308
 309 static int nfs_readdir_page_array_append(struct page *page,
 310                                          const struct nfs_entry *entry,
 311                                          u64 *cookie)
 312 {
 313         struct nfs_cache_array *array;
 314         struct nfs_cache_array_entry *cache_entry;
 315         const char *name;
 316         int ret = -ENOMEM;
 317
 318         name = nfs_readdir_copy_name(entry->name, entry->len);
 319
 320         array = kmap_atomic(page);
 321         if (!name)
 322                 goto out;
 323         ret = nfs_readdir_array_can_expand(array);
 324         if (ret) {
 325                 kfree(name);
 326                 goto out;
 327         }
 328
 329         cache_entry = &array->array[array->size];
 330         cache_entry->cookie = array->last_cookie;
 331         cache_entry->ino = entry->ino;
 332         cache_entry->d_type = entry->d_type;
 333         cache_entry->name_len = entry->len;
 334         cache_entry->name = name;
 335         array->last_cookie = entry->cookie;
 336         if (array->last_cookie <= cache_entry->cookie)
 337                 array->cookies_are_ordered = 0;
 338         array->size++;
 339         if (entry->eof != 0)
 340                 nfs_readdir_array_set_eof(array);
 341 out:
 342         *cookie = array->last_cookie;
 343         kunmap_atomic(array);
 344         return ret;
 345 }
 346
 347 #define NFS_READDIR_COOKIE_MASK (U32_MAX >> 14)
 348 /*
 349  * Hash algorithm allowing content addressible access to sequences
 350  * of directory cookies. Content is addressed by the value of the
 351  * cookie index of the first readdir entry in a page.
 352  *
 353  * The xxhash algorithm is chosen because it is fast, and is supposed
 354  * to result in a decent flat distribution of hashes.
 355  *
 356  * We then select only the first 18 bits to avoid issues with excessive
 357  * memory use for the page cache XArray. 18 bits should allow the caching
 358  * of 262144 pages of sequences of readdir entries. Since each page holds
 359  * 127 readdir entries for a typical 64-bit system, that works out to a
 360  * cache of ~ 33 million entries per directory.
 361  */
 362 static pgoff_t nfs_readdir_page_cookie_hash(u64 cookie)
 363 {
 364         if (cookie == 0)
 365                 return 0;
 366         return xxhash(&cookie, sizeof(cookie), 0) & NFS_READDIR_COOKIE_MASK;
 367 }
 368
 369 static bool nfs_readdir_page_validate(struct page *page, u64 last_cookie,
 370                                       u64 change_attr)
 371 {
 372         struct nfs_cache_array *array = kmap_atomic(page);
 373         int ret = true;
 374
 375         if (array->change_attr != change_attr)
 376                 ret = false;
 377         if (nfs_readdir_array_index_cookie(array) != last_cookie)
 378                 ret = false;
 379         kunmap_atomic(array);
 380         return ret;
 381 }
 382
 383 static void nfs_readdir_page_unlock_and_put(struct page *page)
 384 {
 385         unlock_page(page);
 386         put_page(page);
 387 }
 388
 389 static void nfs_readdir_page_init_and_validate(struct page *page, u64 cookie,
 390                                                u64 change_attr)
 391 {
 392         if (PageUptodate(page)) {
 393                 if (nfs_readdir_page_validate(page, cookie, change_attr))
 394                         return;
 395                 nfs_readdir_clear_array(page);
 396         }
 397         nfs_readdir_page_init_array(page, cookie, change_attr);
 398         SetPageUptodate(page);
 399 }
 400
 401 static struct page *nfs_readdir_page_get_locked(struct address_space *mapping,
 402                                                 u64 cookie, u64 change_attr)
 403 {
 404         pgoff_t index = nfs_readdir_page_cookie_hash(cookie);
 405         struct page *page;
 406
 407         page = grab_cache_page(mapping, index);
 408         if (!page)
 409                 return NULL;
 410         nfs_readdir_page_init_and_validate(page, cookie, change_attr);
 411         return page;
 412 }
 413
 414 static u64 nfs_readdir_page_last_cookie(struct page *page)
 415 {
 416         struct nfs_cache_array *array;
 417         u64 ret;
 418
 419         array = kmap_atomic(page);
 420         ret = array->last_cookie;
 421         kunmap_atomic(array);
 422         return ret;
 423 }
 424
 425 static bool nfs_readdir_page_needs_filling(struct page *page)
 426 {
 427         struct nfs_cache_array *array;
 428         bool ret;
 429
 430         array = kmap_atomic(page);
 431         ret = !nfs_readdir_array_is_full(array);
 432         kunmap_atomic(array);
 433         return ret;
 434 }
 435
 436 static void nfs_readdir_page_set_eof(struct page *page)
 437 {
 438         struct nfs_cache_array *array;
 439
 440         array = kmap_atomic(page);
 441         nfs_readdir_array_set_eof(array);
 442         kunmap_atomic(array);
 443 }
 444
 445 static struct page *nfs_readdir_page_get_next(struct address_space *mapping,
 446                                               u64 cookie, u64 change_attr)
 447 {
 448         pgoff_t index = nfs_readdir_page_cookie_hash(cookie);
 449         struct page *page;
 450
 451         page = grab_cache_page_nowait(mapping, index);
 452         if (!page)
 453                 return NULL;
 454         nfs_readdir_page_init_and_validate(page, cookie, change_attr);
 455         if (nfs_readdir_page_last_cookie(page) != cookie)
 456                 nfs_readdir_page_reinit_array(page, cookie, change_attr);
 457         return page;
 458 }
 459
 460 static inline
 461 int is_32bit_api(void)
 462 {
 463 #ifdef CONFIG_COMPAT
 464         return in_compat_syscall();
 465 #else
 466         return (BITS_PER_LONG == 32);
 467 #endif
 468 }
 469
 470 static
 471 bool nfs_readdir_use_cookie(const struct file *filp)
 472 {
 473         if ((filp->f_mode & FMODE_32BITHASH) ||
 474             (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 475                 return false;
 476         return true;
 477 }
 478
 479 static void nfs_readdir_seek_next_array(struct nfs_cache_array *array,
 480                                         struct nfs_readdir_descriptor *desc)
 481 {
 482         if (array->page_full) {
 483                 desc->last_cookie = array->last_cookie;
 484                 desc->current_index += array->size;
 485                 desc->cache_entry_index = 0;
 486                 desc->page_index++;
 487         } else
 488                 desc->last_cookie = nfs_readdir_array_index_cookie(array);
 489 }
 490
 491 static void nfs_readdir_rewind_search(struct nfs_readdir_descriptor *desc)
 492 {
 493         desc->current_index = 0;
 494         desc->last_cookie = 0;
 495         desc->page_index = 0;
 496 }
 497
 498 static int nfs_readdir_search_for_pos(struct nfs_cache_array *array,
 499                                       struct nfs_readdir_descriptor *desc)
 500 {
 501         loff_t diff = desc->ctx->pos - desc->current_index;
 502         unsigned int index;
 503
 504         if (diff < 0)
 505                 goto out_eof;
 506         if (diff >= array->size) {
 507                 if (array->page_is_eof)
 508                         goto out_eof;
 509                 nfs_readdir_seek_next_array(array, desc);
 510                 return -EAGAIN;
 511         }
 512
 513         index = (unsigned int)diff;
 514         desc->dir_cookie = array->array[index].cookie;
 515         desc->cache_entry_index = index;
 516         return 0;
 517 out_eof:
 518         desc->eof = true;
 519         return -EBADCOOKIE;
 520 }
 521
 522 static bool nfs_readdir_array_cookie_in_range(struct nfs_cache_array *array,
 523                                               u64 cookie)
 524 {
 525         if (!array->cookies_are_ordered)
 526                 return true;
 527         /* Optimisation for monotonically increasing cookies */
 528         if (cookie >= array->last_cookie)
 529                 return false;
 530         if (array->size && cookie < array->array[0].cookie)
 531                 return false;
 532         return true;
 533 }
 534
 535 static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array,
 536                                          struct nfs_readdir_descriptor *desc)
 537 {
 538         unsigned int i;
 539         int status = -EAGAIN;
 540
 541         if (!nfs_readdir_array_cookie_in_range(array, desc->dir_cookie))
 542                 goto check_eof;
 543
 544         for (i = 0; i < array->size; i++) {
 545                 if (array->array[i].cookie == desc->dir_cookie) {
 546                         if (nfs_readdir_use_cookie(desc->file))
 547                                 desc->ctx->pos = desc->dir_cookie;
 548                         else
 549                                 desc->ctx->pos = desc->current_index + i;
 550                         desc->cache_entry_index = i;
 551                         return 0;
 552                 }
 553         }
 554 check_eof:
 555         if (array->page_is_eof) {
 556                 status = -EBADCOOKIE;
 557                 if (desc->dir_cookie == array->last_cookie)
 558                         desc->eof = true;
 559         } else
 560                 nfs_readdir_seek_next_array(array, desc);
 561         return status;
 562 }
 563
 564 static int nfs_readdir_search_array(struct nfs_readdir_descriptor *desc)
 565 {
 566         struct nfs_cache_array *array;
 567         int status;
 568
 569         array = kmap_atomic(desc->page);
 570
 571         if (desc->dir_cookie == 0)
 572                 status = nfs_readdir_search_for_pos(array, desc);
 573         else
 574                 status = nfs_readdir_search_for_cookie(array, desc);
 575
 576         kunmap_atomic(array);
 577         return status;
 578 }
 579
 580 /* Fill a page with xdr information before transferring to the cache page */
 581 static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc,
 582                                   __be32 *verf, u64 cookie,
 583                                   struct page **pages, size_t bufsize,
 584                                   __be32 *verf_res)
 585 {
 586         struct inode *inode = file_inode(desc->file);
 587         struct nfs_readdir_arg arg = {
 588                 .dentry = file_dentry(desc->file),
 589                 .cred = desc->file->f_cred,
 590                 .verf = verf,
 591                 .cookie = cookie,
 592                 .pages = pages,
 593                 .page_len = bufsize,
 594                 .plus = desc->plus,
 595         };
 596         struct nfs_readdir_res res = {
 597                 .verf = verf_res,
 598         };
 599         unsigned long   timestamp, gencount;
 600         int             error;
 601
 602  again:
 603         timestamp = jiffies;
 604         gencount = nfs_inc_attr_generation_counter();
 605         desc->dir_verifier = nfs_save_change_attribute(inode);
 606         error = NFS_PROTO(inode)->readdir(&arg, &res);
 607         if (error < 0) {
 608                 /* We requested READDIRPLUS, but the server doesn't grok it */
 609                 if (error == -ENOTSUPP && desc->plus) {
 610                         NFS_SERVER(inode)->caps &= ~NFS_CAP_READDIRPLUS;
 611                         desc->plus = arg.plus = false;
 612                         goto again;
 613                 }
 614                 goto error;
 615         }
 616         desc->timestamp = timestamp;
 617         desc->gencount = gencount;
 618 error:
 619         return error;
 620 }
 621
 622 static int xdr_decode(struct nfs_readdir_descriptor *desc,
 623                       struct nfs_entry *entry, struct xdr_stream *xdr)
 624 {
 625         struct inode *inode = file_inode(desc->file);
 626         int error;
 627
 628         error = NFS_PROTO(inode)->decode_dirent(xdr, entry, desc->plus);
 629         if (error)
 630                 return error;
 631         entry->fattr->time_start = desc->timestamp;
 632         entry->fattr->gencount = desc->gencount;
 633         return 0;
 634 }
 635
 636 /* Match file and dirent using either filehandle or fileid
 637  * Note: caller is responsible for checking the fsid
 638  */
 639 static
 640 int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry)
 641 {
 642         struct inode *inode;
 643         struct nfs_inode *nfsi;
 644
 645         if (d_really_is_negative(dentry))
 646                 return 0;
 647
 648         inode = d_inode(dentry);
 649         if (is_bad_inode(inode) || NFS_STALE(inode))
 650                 return 0;
 651
 652         nfsi = NFS_I(inode);
 653         if (entry->fattr->fileid != nfsi->fileid)
 654                 return 0;
 655         if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0)
 656                 return 0;
 657         return 1;
 658 }
 659
 660 #define NFS_READDIR_CACHE_USAGE_THRESHOLD (8UL)
 661
 662 static bool nfs_use_readdirplus(struct inode *dir, struct dir_context *ctx,
 663                                 unsigned int cache_hits,
 664                                 unsigned int cache_misses)
 665 {
 666         if (!nfs_server_capable(dir, NFS_CAP_READDIRPLUS))
 667                 return false;
 668         if (ctx->pos == 0 ||
 669             cache_hits + cache_misses > NFS_READDIR_CACHE_USAGE_THRESHOLD)
 670                 return true;
 671         return false;
 672 }
 673
 674 /*
 675  * This function is called by the getattr code to request the
 676  * use of readdirplus to accelerate any future lookups in the same
 677  * directory.
 678  */
 679 void nfs_readdir_record_entry_cache_hit(struct inode *dir)
 680 {
 681         struct nfs_inode *nfsi = NFS_I(dir);
 682         struct nfs_open_dir_context *ctx;
 683
 684         if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
 685             S_ISDIR(dir->i_mode)) {
 686                 rcu_read_lock();
 687                 list_for_each_entry_rcu (ctx, &nfsi->open_files, list)
 688                         atomic_inc(&ctx->cache_hits);
 689                 rcu_read_unlock();
 690         }
 691 }
 692
 693 /*
 694  * This function is mainly for use by nfs_getattr().
 695  *
 696  * If this is an 'ls -l', we want to force use of readdirplus.
 697  */
 698 void nfs_readdir_record_entry_cache_miss(struct inode *dir)
 699 {
 700         struct nfs_inode *nfsi = NFS_I(dir);
 701         struct nfs_open_dir_context *ctx;
 702
 703         if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) &&
 704             S_ISDIR(dir->i_mode)) {
 705                 rcu_read_lock();
 706                 list_for_each_entry_rcu (ctx, &nfsi->open_files, list)
 707                         atomic_inc(&ctx->cache_misses);
 708                 rcu_read_unlock();
 709         }
 710 }
 711
 712 static void nfs_lookup_advise_force_readdirplus(struct inode *dir,
 713                                                 unsigned int flags)
 714 {
 715         if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
 716                 return;
 717         if (flags & (LOOKUP_EXCL | LOOKUP_PARENT | LOOKUP_REVAL))
 718                 return;
 719         nfs_readdir_record_entry_cache_miss(dir);
 720 }
 721
 722 static
 723 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry,
 724                 unsigned long dir_verifier)
 725 {
 726         struct qstr filename = QSTR_INIT(entry->name, entry->len);
 727         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 728         struct dentry *dentry;
 729         struct dentry *alias;
 730         struct inode *inode;
 731         int status;
 732
 733         if (!(entry->fattr->valid & NFS_ATTR_FATTR_FILEID))
 734                 return;
 735         if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID))
 736                 return;
 737         if (filename.len == 0)
 738                 return;
 739         /* Validate that the name doesn't contain any illegal '\0' */
 740         if (strnlen(filename.name, filename.len) != filename.len)
 741                 return;
 742         /* ...or '/' */
 743         if (strnchr(filename.name, filename.len, '/'))
 744                 return;
 745         if (filename.name[0] == '.') {
 746                 if (filename.len == 1)
 747                         return;
 748                 if (filename.len == 2 && filename.name[1] == '.')
 749                         return;
 750         }
 751         filename.hash = full_name_hash(parent, filename.name, filename.len);
 752
 753         dentry = d_lookup(parent, &filename);
 754 again:
 755         if (!dentry) {
 756                 dentry = d_alloc_parallel(parent, &filename, &wq);
 757                 if (IS_ERR(dentry))
 758                         return;
 759         }
 760         if (!d_in_lookup(dentry)) {
 761                 /* Is there a mountpoint here? If so, just exit */
 762                 if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid,
 763                                         &entry->fattr->fsid))
 764                         goto out;
 765                 if (nfs_same_file(dentry, entry)) {
 766                         if (!entry->fh->size)
 767                                 goto out;
 768                         nfs_set_verifier(dentry, dir_verifier);
 769                         status = nfs_refresh_inode(d_inode(dentry), entry->fattr);
 770                         if (!status)
 771                                 nfs_setsecurity(d_inode(dentry), entry->fattr);
 772                         trace_nfs_readdir_lookup_revalidate(d_inode(parent),
 773                                                             dentry, 0, status);
 774                         goto out;
 775                 } else {
 776                         trace_nfs_readdir_lookup_revalidate_failed(
 777                                 d_inode(parent), dentry, 0);
 778                         d_invalidate(dentry);
 779                         dput(dentry);
 780                         dentry = NULL;
 781                         goto again;
 782                 }
 783         }
 784         if (!entry->fh->size) {
 785                 d_lookup_done(dentry);
 786                 goto out;
 787         }
 788
 789         inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr);
 790         alias = d_splice_alias(inode, dentry);
 791         d_lookup_done(dentry);
 792         if (alias) {
 793                 if (IS_ERR(alias))
 794                         goto out;
 795                 dput(dentry);
 796                 dentry = alias;
 797         }
 798         nfs_set_verifier(dentry, dir_verifier);
 799         trace_nfs_readdir_lookup(d_inode(parent), dentry, 0);
 800 out:
 801         dput(dentry);
 802 }
 803
 804 static int nfs_readdir_entry_decode(struct nfs_readdir_descriptor *desc,
 805                                     struct nfs_entry *entry,
 806                                     struct xdr_stream *stream)
 807 {
 808         int ret;
 809
 810         if (entry->fattr->label)
 811                 entry->fattr->label->len = NFS4_MAXLABELLEN;
 812         ret = xdr_decode(desc, entry, stream);
 813         if (ret || !desc->plus)
 814                 return ret;
 815         nfs_prime_dcache(file_dentry(desc->file), entry, desc->dir_verifier);
 816         return 0;
 817 }
 818
 819 /* Perform conversion from xdr to cache array */
 820 static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc,
 821                                    struct nfs_entry *entry,
 822                                    struct page **xdr_pages, unsigned int buflen,
 823                                    struct page **arrays, size_t narrays,
 824                                    u64 change_attr)
 825 {
 826         struct address_space *mapping = desc->file->f_mapping;
 827         struct xdr_stream stream;
 828         struct xdr_buf buf;
 829         struct page *scratch, *new, *page = *arrays;
 830         u64 cookie;
 831         int status;
 832
 833         scratch = alloc_page(GFP_KERNEL);
 834         if (scratch == NULL)
 835                 return -ENOMEM;
 836
 837         xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen);
 838         xdr_set_scratch_page(&stream, scratch);
 839
 840         do {
 841                 status = nfs_readdir_entry_decode(desc, entry, &stream);
 842                 if (status != 0)
 843                         break;
 844
 845                 status = nfs_readdir_page_array_append(page, entry, &cookie);
 846                 if (status != -ENOSPC)
 847                         continue;
 848
 849                 if (page->mapping != mapping) {
 850                         if (!--narrays)
 851                                 break;
 852                         new = nfs_readdir_page_array_alloc(cookie, GFP_KERNEL);
 853                         if (!new)
 854                                 break;
 855                         arrays++;
 856                         *arrays = page = new;
 857                 } else {
 858                         new = nfs_readdir_page_get_next(mapping, cookie,
 859                                                         change_attr);
 860                         if (!new)
 861                                 break;
 862                         if (page != *arrays)
 863                                 nfs_readdir_page_unlock_and_put(page);
 864                         page = new;
 865                 }
 866                 desc->page_index_max++;
 867                 status = nfs_readdir_page_array_append(page, entry, &cookie);
 868         } while (!status && !entry->eof);
 869
 870         switch (status) {
 871         case -EBADCOOKIE:
 872                 if (!entry->eof)
 873                         break;
 874                 nfs_readdir_page_set_eof(page);
 875                 fallthrough;
 876         case -EAGAIN:
 877                 status = 0;
 878                 break;
 879         case -ENOSPC:
 880                 status = 0;
 881                 if (!desc->plus)
 882                         break;
 883                 while (!nfs_readdir_entry_decode(desc, entry, &stream))
 884                         ;
 885         }
 886
 887         if (page != *arrays)
 888                 nfs_readdir_page_unlock_and_put(page);
 889
 890         put_page(scratch);
 891         return status;
 892 }
 893
 894 static void nfs_readdir_free_pages(struct page **pages, size_t npages)
 895 {
 896         while (npages--)
 897                 put_page(pages[npages]);
 898         kfree(pages);
 899 }
 900
 901 /*
 902  * nfs_readdir_alloc_pages() will allocate pages that must be freed with a call
 903  * to nfs_readdir_free_pages()
 904  */
 905 static struct page **nfs_readdir_alloc_pages(size_t npages)
 906 {
 907         struct page **pages;
 908         size_t i;
 909
 910         pages = kmalloc_array(npages, sizeof(*pages), GFP_KERNEL);
 911         if (!pages)
 912                 return NULL;
 913         for (i = 0; i < npages; i++) {
 914                 struct page *page = alloc_page(GFP_KERNEL);
 915                 if (page == NULL)
 916                         goto out_freepages;
 917                 pages[i] = page;
 918         }
 919         return pages;
 920
 921 out_freepages:
 922         nfs_readdir_free_pages(pages, i);
 923         return NULL;
 924 }
 925
 926 static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc,
 927                                     __be32 *verf_arg, __be32 *verf_res,
 928                                     struct page **arrays, size_t narrays)
 929 {
 930         u64 change_attr;
 931         struct page **pages;
 932         struct page *page = *arrays;
 933         struct nfs_entry *entry;
 934         size_t array_size;
 935         struct inode *inode = file_inode(desc->file);
 936         unsigned int dtsize = desc->dtsize;
 937         unsigned int pglen;
 938         int status = -ENOMEM;
 939
 940         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 941         if (!entry)
 942                 return -ENOMEM;
 943         entry->cookie = nfs_readdir_page_last_cookie(page);
 944         entry->fh = nfs_alloc_fhandle();
 945         entry->fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
 946         entry->server = NFS_SERVER(inode);
 947         if (entry->fh == NULL || entry->fattr == NULL)
 948                 goto out;
 949
 950         array_size = (dtsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
 951         pages = nfs_readdir_alloc_pages(array_size);
 952         if (!pages)
 953                 goto out;
 954
 955         change_attr = inode_peek_iversion_raw(inode);
 956         status = nfs_readdir_xdr_filler(desc, verf_arg, entry->cookie, pages,
 957                                         dtsize, verf_res);
 958         if (status < 0)
 959                 goto free_pages;
 960
 961         pglen = status;
 962         if (pglen != 0)
 963                 status = nfs_readdir_page_filler(desc, entry, pages, pglen,
 964                                                  arrays, narrays, change_attr);
 965         else
 966                 nfs_readdir_page_set_eof(page);
 967         desc->buffer_fills++;
 968
 969 free_pages:
 970         nfs_readdir_free_pages(pages, array_size);
 971 out:
 972         nfs_free_fattr(entry->fattr);
 973         nfs_free_fhandle(entry->fh);
 974         kfree(entry);
 975         return status;
 976 }
 977
 978 static void nfs_readdir_page_put(struct nfs_readdir_descriptor *desc)
 979 {
 980         put_page(desc->page);
 981         desc->page = NULL;
 982 }
 983
 984 static void
 985 nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc)
 986 {
 987         unlock_page(desc->page);
 988         nfs_readdir_page_put(desc);
 989 }
 990
 991 static struct page *
 992 nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc)
 993 {
 994         struct address_space *mapping = desc->file->f_mapping;
 995         u64 change_attr = inode_peek_iversion_raw(mapping->host);
 996         u64 cookie = desc->last_cookie;
 997         struct page *page;
 998
 999         page = nfs_readdir_page_get_locked(mapping, cookie, change_attr);
1000         if (!page)
1001                 return NULL;
1002         if (desc->clear_cache && !nfs_readdir_page_needs_filling(page))
1003                 nfs_readdir_page_reinit_array(page, cookie, change_attr);
1004         return page;
1005 }
1006
1007 /*
1008  * Returns 0 if desc->dir_cookie was found on page desc->page_index
1009  * and locks the page to prevent removal from the page cache.
1010  */
1011 static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
1012 {
1013         struct inode *inode = file_inode(desc->file);
1014         struct nfs_inode *nfsi = NFS_I(inode);
1015         __be32 verf[NFS_DIR_VERIFIER_SIZE];
1016         int res;
1017
1018         desc->page = nfs_readdir_page_get_cached(desc);
1019         if (!desc->page)
1020                 return -ENOMEM;
1021         if (nfs_readdir_page_needs_filling(desc->page)) {
1022                 /* Grow the dtsize if we had to go back for more pages */
1023                 if (desc->page_index == desc->page_index_max)
1024                         nfs_grow_dtsize(desc);
1025                 desc->page_index_max = desc->page_index;
1026                 trace_nfs_readdir_cache_fill(desc->file, nfsi->cookieverf,
1027                                              desc->last_cookie,
1028                                              desc->page->index, desc->dtsize);
1029                 res = nfs_readdir_xdr_to_array(desc, nfsi->cookieverf, verf,
1030                                                &desc->page, 1);
1031                 if (res < 0) {
1032                         nfs_readdir_page_unlock_and_put_cached(desc);
1033                         trace_nfs_readdir_cache_fill_done(inode, res);
1034                         if (res == -EBADCOOKIE || res == -ENOTSYNC) {
1035                                 invalidate_inode_pages2(desc->file->f_mapping);
1036                                 nfs_readdir_rewind_search(desc);
1037                                 trace_nfs_readdir_invalidate_cache_range(
1038                                         inode, 0, MAX_LFS_FILESIZE);
1039                                 return -EAGAIN;
1040                         }
1041                         return res;
1042                 }
1043                 /*
1044                  * Set the cookie verifier if the page cache was empty
1045                  */
1046                 if (desc->last_cookie == 0 &&
1047                     memcmp(nfsi->cookieverf, verf, sizeof(nfsi->cookieverf))) {
1048                         memcpy(nfsi->cookieverf, verf,
1049                                sizeof(nfsi->cookieverf));
1050                         invalidate_inode_pages2_range(desc->file->f_mapping, 1,
1051                                                       -1);
1052                         trace_nfs_readdir_invalidate_cache_range(
1053                                 inode, 1, MAX_LFS_FILESIZE);
1054                 }
1055                 desc->clear_cache = false;
1056         }
1057         res = nfs_readdir_search_array(desc);
1058         if (res == 0)
1059                 return 0;
1060         nfs_readdir_page_unlock_and_put_cached(desc);
1061         return res;
1062 }
1063
1064 /* Search for desc->dir_cookie from the beginning of the page cache */
1065 static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc)
1066 {
1067         int res;
1068
1069         do {
1070                 res = find_and_lock_cache_page(desc);
1071         } while (res == -EAGAIN);
1072         return res;
1073 }
1074
1075 /*
1076  * Once we've found the start of the dirent within a page: fill 'er up...
1077  */
1078 static void nfs_do_filldir(struct nfs_readdir_descriptor *desc,
1079                            const __be32 *verf)
1080 {
1081         struct file     *file = desc->file;
1082         struct nfs_cache_array *array;
1083         unsigned int i;
1084
1085         array = kmap(desc->page);
1086         for (i = desc->cache_entry_index; i < array->size; i++) {
1087                 struct nfs_cache_array_entry *ent;
1088
1089                 ent = &array->array[i];
1090                 if (!dir_emit(desc->ctx, ent->name, ent->name_len,
1091                     nfs_compat_user_ino64(ent->ino), ent->d_type)) {
1092                         desc->eob = true;
1093                         break;
1094                 }
1095                 memcpy(desc->verf, verf, sizeof(desc->verf));
1096                 if (i == array->size - 1) {
1097                         desc->dir_cookie = array->last_cookie;
1098                         nfs_readdir_seek_next_array(array, desc);
1099                 } else {
1100                         desc->dir_cookie = array->array[i + 1].cookie;
1101                         desc->last_cookie = array->array[0].cookie;
1102                 }
1103                 if (nfs_readdir_use_cookie(file))
1104                         desc->ctx->pos = desc->dir_cookie;
1105                 else
1106                         desc->ctx->pos++;
1107         }
1108         if (array->page_is_eof)
1109                 desc->eof = !desc->eob;
1110
1111         kunmap(desc->page);
1112         dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %llu\n",
1113                         (unsigned long long)desc->dir_cookie);
1114 }
1115
1116 /*
1117  * If we cannot find a cookie in our cache, we suspect that this is
1118  * because it points to a deleted file, so we ask the server to return
1119  * whatever it thinks is the next entry. We then feed this to filldir.
1120  * If all goes well, we should then be able to find our way round the
1121  * cache on the next call to readdir_search_pagecache();
1122  *
1123  * NOTE: we cannot add the anonymous page to the pagecache because
1124  *       the data it contains might not be page aligned. Besides,
1125  *       we should already have a complete representation of the
1126  *       directory in the page cache by the time we get here.
1127  */
1128 static int uncached_readdir(struct nfs_readdir_descriptor *desc)
1129 {
1130         struct page     **arrays;
1131         size_t          i, sz = 512;
1132         __be32          verf[NFS_DIR_VERIFIER_SIZE];
1133         int             status = -ENOMEM;
1134
1135         dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %llu\n",
1136                         (unsigned long long)desc->dir_cookie);
1137
1138         arrays = kcalloc(sz, sizeof(*arrays), GFP_KERNEL);
1139         if (!arrays)
1140                 goto out;
1141         arrays[0] = nfs_readdir_page_array_alloc(desc->dir_cookie, GFP_KERNEL);
1142         if (!arrays[0])
1143                 goto out;
1144
1145         desc->page_index = 0;
1146         desc->cache_entry_index = 0;
1147         desc->last_cookie = desc->dir_cookie;
1148         desc->page_index_max = 0;
1149
1150         trace_nfs_readdir_uncached(desc->file, desc->verf, desc->last_cookie,
1151                                    -1, desc->dtsize);
1152
1153         status = nfs_readdir_xdr_to_array(desc, desc->verf, verf, arrays, sz);
1154         if (status < 0) {
1155                 trace_nfs_readdir_uncached_done(file_inode(desc->file), status);
1156                 goto out_free;
1157         }
1158
1159         for (i = 0; !desc->eob && i < sz && arrays[i]; i++) {
1160                 desc->page = arrays[i];
1161                 nfs_do_filldir(desc, verf);
1162         }
1163         desc->page = NULL;
1164
1165         /*
1166          * Grow the dtsize if we have to go back for more pages,
1167          * or shrink it if we're reading too many.
1168          */
1169         if (!desc->eof) {
1170                 if (!desc->eob)
1171                         nfs_grow_dtsize(desc);
1172                 else if (desc->buffer_fills == 1 &&
1173                          i < (desc->page_index_max >> 1))
1174                         nfs_shrink_dtsize(desc);
1175         }
1176 out_free:
1177         for (i = 0; i < sz && arrays[i]; i++)
1178                 nfs_readdir_page_array_free(arrays[i]);
1179 out:
1180         if (!nfs_readdir_use_cookie(desc->file))
1181                 nfs_readdir_rewind_search(desc);
1182         desc->page_index_max = -1;
1183         kfree(arrays);
1184         dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status);
1185         return status;
1186 }
1187
1188 #define NFS_READDIR_CACHE_MISS_THRESHOLD (16UL)
1189
1190 static bool nfs_readdir_handle_cache_misses(struct inode *inode,
1191                                             struct nfs_readdir_descriptor *desc,
1192                                             unsigned int cache_misses,
1193                                             bool force_clear)
1194 {
1195         if (desc->ctx->pos == 0 || !desc->plus)
1196                 return false;
1197         if (cache_misses <= NFS_READDIR_CACHE_MISS_THRESHOLD && !force_clear)
1198                 return false;
1199         trace_nfs_readdir_force_readdirplus(inode);
1200         return true;
1201 }
1202
1203 /* The file offset position represents the dirent entry number.  A
1204    last cookie cache takes care of the common case of reading the
1205    whole directory.
1206  */
1207 static int nfs_readdir(struct file *file, struct dir_context *ctx)
1208 {
1209         struct dentry   *dentry = file_dentry(file);
1210         struct inode    *inode = d_inode(dentry);
1211         struct nfs_inode *nfsi = NFS_I(inode);
1212         struct nfs_open_dir_context *dir_ctx = file->private_data;
1213         struct nfs_readdir_descriptor *desc;
1214         unsigned int cache_hits, cache_misses;
1215         bool force_clear;
1216         int res;
1217
1218         dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n",
1219                         file, (long long)ctx->pos);
1220         nfs_inc_stats(inode, NFSIOS_VFSGETDENTS);
1221
1222         /*
1223          * ctx->pos points to the dirent entry number.
1224          * *desc->dir_cookie has the cookie for the next entry. We have
1225          * to either find the entry with the appropriate number or
1226          * revalidate the cookie.
1227          */
1228         nfs_revalidate_mapping(inode, file->f_mapping);
1229
1230         res = -ENOMEM;
1231         desc = kzalloc(sizeof(*desc), GFP_KERNEL);
1232         if (!desc)
1233                 goto out;
1234         desc->file = file;
1235         desc->ctx = ctx;
1236         desc->page_index_max = -1;
1237
1238         spin_lock(&file->f_lock);
1239         desc->dir_cookie = dir_ctx->dir_cookie;
1240         desc->page_index = dir_ctx->page_index;
1241         desc->last_cookie = dir_ctx->last_cookie;
1242         desc->attr_gencount = dir_ctx->attr_gencount;
1243         desc->eof = dir_ctx->eof;
1244         nfs_set_dtsize(desc, dir_ctx->dtsize);
1245         memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf));
1246         cache_hits = atomic_xchg(&dir_ctx->cache_hits, 0);
1247         cache_misses = atomic_xchg(&dir_ctx->cache_misses, 0);
1248         force_clear = dir_ctx->force_clear;
1249         spin_unlock(&file->f_lock);
1250
1251         if (desc->eof) {
1252                 res = 0;
1253                 goto out_free;
1254         }
1255
1256         desc->plus = nfs_use_readdirplus(inode, ctx, cache_hits, cache_misses);
1257         force_clear = nfs_readdir_handle_cache_misses(inode, desc, cache_misses,
1258                                                       force_clear);
1259         desc->clear_cache = force_clear;
1260
1261         do {
1262                 res = readdir_search_pagecache(desc);
1263
1264                 if (res == -EBADCOOKIE) {
1265                         res = 0;
1266                         /* This means either end of directory */
1267                         if (desc->dir_cookie && !desc->eof) {
1268                                 /* Or that the server has 'lost' a cookie */
1269                                 res = uncached_readdir(desc);
1270                                 if (res == 0)
1271                                         continue;
1272                                 if (res == -EBADCOOKIE || res == -ENOTSYNC)
1273                                         res = 0;
1274                         }
1275                         break;
1276                 }
1277                 if (res == -ETOOSMALL && desc->plus) {
1278                         nfs_zap_caches(inode);
1279                         desc->plus = false;
1280                         desc->eof = false;
1281                         continue;
1282                 }
1283                 if (res < 0)
1284                         break;
1285
1286                 nfs_do_filldir(desc, nfsi->cookieverf);
1287                 nfs_readdir_page_unlock_and_put_cached(desc);
1288                 if (desc->page_index == desc->page_index_max)
1289                         desc->clear_cache = force_clear;
1290         } while (!desc->eob && !desc->eof);
1291
1292         spin_lock(&file->f_lock);
1293         dir_ctx->dir_cookie = desc->dir_cookie;
1294         dir_ctx->last_cookie = desc->last_cookie;
1295         dir_ctx->attr_gencount = desc->attr_gencount;
1296         dir_ctx->page_index = desc->page_index;
1297         dir_ctx->force_clear = force_clear;
1298         dir_ctx->eof = desc->eof;
1299         dir_ctx->dtsize = desc->dtsize;
1300         memcpy(dir_ctx->verf, desc->verf, sizeof(dir_ctx->verf));
1301         spin_unlock(&file->f_lock);
1302 out_free:
1303         kfree(desc);
1304
1305 out:
1306         dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res);
1307         return res;
1308 }
1309
1310 static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
1311 {
1312         struct nfs_open_dir_context *dir_ctx = filp->private_data;
1313
1314         dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n",
1315                         filp, offset, whence);
1316
1317         switch (whence) {
1318         default:
1319                 return -EINVAL;
1320         case SEEK_SET:
1321                 if (offset < 0)
1322                         return -EINVAL;
1323                 spin_lock(&filp->f_lock);
1324                 break;
1325         case SEEK_CUR:
1326                 if (offset == 0)
1327                         return filp->f_pos;
1328                 spin_lock(&filp->f_lock);
1329                 offset += filp->f_pos;
1330                 if (offset < 0) {
1331                         spin_unlock(&filp->f_lock);
1332                         return -EINVAL;
1333                 }
1334         }
1335         if (offset != filp->f_pos) {
1336                 filp->f_pos = offset;
1337                 dir_ctx->page_index = 0;
1338                 if (!nfs_readdir_use_cookie(filp)) {
1339                         dir_ctx->dir_cookie = 0;
1340                         dir_ctx->last_cookie = 0;
1341                 } else {
1342                         dir_ctx->dir_cookie = offset;
1343                         dir_ctx->last_cookie = offset;
1344                 }
1345                 dir_ctx->eof = false;
1346         }
1347         spin_unlock(&filp->f_lock);
1348         return offset;
1349 }
1350
1351 /*
1352  * All directory operations under NFS are synchronous, so fsync()
1353  * is a dummy operation.
1354  */
1355 static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end,
1356                          int datasync)
1357 {
1358         dfprintk(FILE, "NFS: fsync dir(%pD2) datasync %d\n", filp, datasync);
1359
1360         nfs_inc_stats(file_inode(filp), NFSIOS_VFSFSYNC);
1361         return 0;
1362 }
1363
1364 /**
1365  * nfs_force_lookup_revalidate - Mark the directory as having changed
1366  * @dir: pointer to directory inode
1367  *
1368  * This forces the revalidation code in nfs_lookup_revalidate() to do a
1369  * full lookup on all child dentries of 'dir' whenever a change occurs
1370  * on the server that might have invalidated our dcache.
1371  *
1372  * Note that we reserve bit '0' as a tag to let us know when a dentry
1373  * was revalidated while holding a delegation on its inode.
1374  *
1375  * The caller should be holding dir->i_lock
1376  */
1377 void nfs_force_lookup_revalidate(struct inode *dir)
1378 {
1379         NFS_I(dir)->cache_change_attribute += 2;
1380 }
1381 EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate);
1382
1383 /**
1384  * nfs_verify_change_attribute - Detects NFS remote directory changes
1385  * @dir: pointer to parent directory inode
1386  * @verf: previously saved change attribute
1387  *
1388  * Return "false" if the verifiers doesn't match the change attribute.
1389  * This would usually indicate that the directory contents have changed on
1390  * the server, and that any dentries need revalidating.
1391  */
1392 static bool nfs_verify_change_attribute(struct inode *dir, unsigned long verf)
1393 {
1394         return (verf & ~1UL) == nfs_save_change_attribute(dir);
1395 }
1396
1397 static void nfs_set_verifier_delegated(unsigned long *verf)
1398 {
1399         *verf |= 1UL;
1400 }
1401
1402 #if IS_ENABLED(CONFIG_NFS_V4)
1403 static void nfs_unset_verifier_delegated(unsigned long *verf)
1404 {
1405         *verf &= ~1UL;
1406 }
1407 #endif /* IS_ENABLED(CONFIG_NFS_V4) */
1408
1409 static bool nfs_test_verifier_delegated(unsigned long verf)
1410 {
1411         return verf & 1;
1412 }
1413
1414 static bool nfs_verifier_is_delegated(struct dentry *dentry)
1415 {
1416         return nfs_test_verifier_delegated(dentry->d_time);
1417 }
1418
1419 static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf)
1420 {
1421         struct inode *inode = d_inode(dentry);
1422         struct inode *dir = d_inode(dentry->d_parent);
1423
1424         if (!nfs_verify_change_attribute(dir, verf))
1425                 return;
1426         if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
1427                 nfs_set_verifier_delegated(&verf);
1428         dentry->d_time = verf;
1429 }
1430
1431 /**
1432  * nfs_set_verifier - save a parent directory verifier in the dentry
1433  * @dentry: pointer to dentry
1434  * @verf: verifier to save
1435  *
1436  * Saves the parent directory verifier in @dentry. If the inode has
1437  * a delegation, we also tag the dentry as having been revalidated
1438  * while holding a delegation so that we know we don't have to
1439  * look it up again after a directory change.
1440  */
1441 void nfs_set_verifier(struct dentry *dentry, unsigned long verf)
1442 {
1443
1444         spin_lock(&dentry->d_lock);
1445         nfs_set_verifier_locked(dentry, verf);
1446         spin_unlock(&dentry->d_lock);
1447 }
1448 EXPORT_SYMBOL_GPL(nfs_set_verifier);
1449
1450 #if IS_ENABLED(CONFIG_NFS_V4)
1451 /**
1452  * nfs_clear_verifier_delegated - clear the dir verifier delegation tag
1453  * @inode: pointer to inode
1454  *
1455  * Iterates through the dentries in the inode alias list and clears
1456  * the tag used to indicate that the dentry has been revalidated
1457  * while holding a delegation.
1458  * This function is intended for use when the delegation is being
1459  * returned or revoked.
1460  */
1461 void nfs_clear_verifier_delegated(struct inode *inode)
1462 {
1463         struct dentry *alias;
1464
1465         if (!inode)
1466                 return;
1467         spin_lock(&inode->i_lock);
1468         hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
1469                 spin_lock(&alias->d_lock);
1470                 nfs_unset_verifier_delegated(&alias->d_time);
1471                 spin_unlock(&alias->d_lock);
1472         }
1473         spin_unlock(&inode->i_lock);
1474 }
1475 EXPORT_SYMBOL_GPL(nfs_clear_verifier_delegated);
1476 #endif /* IS_ENABLED(CONFIG_NFS_V4) */
1477
1478 static int nfs_dentry_verify_change(struct inode *dir, struct dentry *dentry)
1479 {
1480         if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE) &&
1481             d_really_is_negative(dentry))
1482                 return dentry->d_time == inode_peek_iversion_raw(dir);
1483         return nfs_verify_change_attribute(dir, dentry->d_time);
1484 }
1485
1486 /*
1487  * A check for whether or not the parent directory has changed.
1488  * In the case it has, we assume that the dentries are untrustworthy
1489  * and may need to be looked up again.
1490  * If rcu_walk prevents us from performing a full check, return 0.
1491  */
1492 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry,
1493                               int rcu_walk)
1494 {
1495         if (IS_ROOT(dentry))
1496                 return 1;
1497         if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
1498                 return 0;
1499         if (!nfs_dentry_verify_change(dir, dentry))
1500                 return 0;
1501         /* Revalidate nfsi->cache_change_attribute before we declare a match */
1502         if (nfs_mapping_need_revalidate_inode(dir)) {
1503                 if (rcu_walk)
1504                         return 0;
1505                 if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
1506                         return 0;
1507         }
1508         if (!nfs_dentry_verify_change(dir, dentry))
1509                 return 0;
1510         return 1;
1511 }
1512
1513 /*
1514  * Use intent information to check whether or not we're going to do
1515  * an O_EXCL create using this path component.
1516  */
1517 static int nfs_is_exclusive_create(struct inode *dir, unsigned int flags)
1518 {
1519         if (NFS_PROTO(dir)->version == 2)
1520                 return 0;
1521         return flags & LOOKUP_EXCL;
1522 }
1523
1524 /*
1525  * Inode and filehandle revalidation for lookups.
1526  *
1527  * We force revalidation in the cases where the VFS sets LOOKUP_REVAL,
1528  * or if the intent information indicates that we're about to open this
1529  * particular file and the "nocto" mount flag is not set.
1530  *
1531  */
1532 static
1533 int nfs_lookup_verify_inode(struct inode *inode, unsigned int flags)
1534 {
1535         struct nfs_server *server = NFS_SERVER(inode);
1536         int ret;
1537
1538         if (IS_AUTOMOUNT(inode))
1539                 return 0;
1540
1541         if (flags & LOOKUP_OPEN) {
1542                 switch (inode->i_mode & S_IFMT) {
1543                 case S_IFREG:
1544                         /* A NFSv4 OPEN will revalidate later */
1545                         if (server->caps & NFS_CAP_ATOMIC_OPEN)
1546                                 goto out;
1547                         fallthrough;
1548                 case S_IFDIR:
1549                         if (server->flags & NFS_MOUNT_NOCTO)
1550                                 break;
1551                         /* NFS close-to-open cache consistency validation */
1552                         goto out_force;
1553                 }
1554         }
1555
1556         /* VFS wants an on-the-wire revalidation */
1557         if (flags & LOOKUP_REVAL)
1558                 goto out_force;
1559 out:
1560         if (inode->i_nlink > 0 ||
1561             (inode->i_nlink == 0 &&
1562              test_bit(NFS_INO_PRESERVE_UNLINKED, &NFS_I(inode)->flags)))
1563                 return 0;
1564         else
1565                 return -ESTALE;
1566 out_force:
1567         if (flags & LOOKUP_RCU)
1568                 return -ECHILD;
1569         ret = __nfs_revalidate_inode(server, inode);
1570         if (ret != 0)
1571                 return ret;
1572         goto out;
1573 }
1574
1575 static void nfs_mark_dir_for_revalidate(struct inode *inode)
1576 {
1577         spin_lock(&inode->i_lock);
1578         nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE);
1579         spin_unlock(&inode->i_lock);
1580 }
1581
1582 /*
1583  * We judge how long we want to trust negative
1584  * dentries by looking at the parent inode mtime.
1585  *
1586  * If parent mtime has changed, we revalidate, else we wait for a
1587  * period corresponding to the parent's attribute cache timeout value.
1588  *
1589  * If LOOKUP_RCU prevents us from performing a full check, return 1
1590  * suggesting a reval is needed.
1591  *
1592  * Note that when creating a new file, or looking up a rename target,
1593  * then it shouldn't be necessary to revalidate a negative dentry.
1594  */
1595 static inline
1596 int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
1597                        unsigned int flags)
1598 {
1599         if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
1600                 return 0;
1601         if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG)
1602                 return 1;
1603         /* Case insensitive server? Revalidate negative dentries */
1604         if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
1605                 return 1;
1606         return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU);
1607 }
1608
1609 static int
1610 nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry,
1611                            struct inode *inode, int error)
1612 {
1613         switch (error) {
1614         case 1:
1615                 break;
1616         case 0:
1617                 /*
1618                  * We can't d_drop the root of a disconnected tree:
1619                  * its d_hash is on the s_anon list and d_drop() would hide
1620                  * it from shrink_dcache_for_unmount(), leading to busy
1621                  * inodes on unmount and further oopses.
1622                  */
1623                 if (inode && IS_ROOT(dentry))
1624                         error = 1;
1625                 break;
1626         }
1627         trace_nfs_lookup_revalidate_exit(dir, dentry, 0, error);
1628         return error;
1629 }
1630
1631 static int
1632 nfs_lookup_revalidate_negative(struct inode *dir, struct dentry *dentry,
1633                                unsigned int flags)
1634 {
1635         int ret = 1;
1636         if (nfs_neg_need_reval(dir, dentry, flags)) {
1637                 if (flags & LOOKUP_RCU)
1638                         return -ECHILD;
1639                 ret = 0;
1640         }
1641         return nfs_lookup_revalidate_done(dir, dentry, NULL, ret);
1642 }
1643
1644 static int
1645 nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry,
1646                                 struct inode *inode)
1647 {
1648         nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
1649         return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
1650 }
1651
1652 static int nfs_lookup_revalidate_dentry(struct inode *dir,
1653                                         struct dentry *dentry,
1654                                         struct inode *inode, unsigned int flags)
1655 {
1656         struct nfs_fh *fhandle;
1657         struct nfs_fattr *fattr;
1658         unsigned long dir_verifier;
1659         int ret;
1660
1661         trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
1662
1663         ret = -ENOMEM;
1664         fhandle = nfs_alloc_fhandle();
1665         fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
1666         if (fhandle == NULL || fattr == NULL)
1667                 goto out;
1668
1669         dir_verifier = nfs_save_change_attribute(dir);
1670         ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr);
1671         if (ret < 0) {
1672                 switch (ret) {
1673                 case -ESTALE:
1674                 case -ENOENT:
1675                         ret = 0;
1676                         break;
1677                 case -ETIMEDOUT:
1678                         if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL)
1679                                 ret = 1;
1680                 }
1681                 goto out;
1682         }
1683
1684         /* Request help from readdirplus */
1685         nfs_lookup_advise_force_readdirplus(dir, flags);
1686
1687         ret = 0;
1688         if (nfs_compare_fh(NFS_FH(inode), fhandle))
1689                 goto out;
1690         if (nfs_refresh_inode(inode, fattr) < 0)
1691                 goto out;
1692
1693         nfs_setsecurity(inode, fattr);
1694         nfs_set_verifier(dentry, dir_verifier);
1695
1696         ret = 1;
1697 out:
1698         nfs_free_fattr(fattr);
1699         nfs_free_fhandle(fhandle);
1700
1701         /*
1702          * If the lookup failed despite the dentry change attribute being
1703          * a match, then we should revalidate the directory cache.
1704          */
1705         if (!ret && nfs_dentry_verify_change(dir, dentry))
1706                 nfs_mark_dir_for_revalidate(dir);
1707         return nfs_lookup_revalidate_done(dir, dentry, inode, ret);
1708 }
1709
1710 /*
1711  * This is called every time the dcache has a lookup hit,
1712  * and we should check whether we can really trust that
1713  * lookup.
1714  *
1715  * NOTE! The hit can be a negative hit too, don't assume
1716  * we have an inode!
1717  *
1718  * If the parent directory is seen to have changed, we throw out the
1719  * cached dentry and do a new lookup.
1720  */
1721 static int
1722 nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
1723                          unsigned int flags)
1724 {
1725         struct inode *inode;
1726         int error;
1727
1728         nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
1729         inode = d_inode(dentry);
1730
1731         if (!inode)
1732                 return nfs_lookup_revalidate_negative(dir, dentry, flags);
1733
1734         if (is_bad_inode(inode)) {
1735                 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
1736                                 __func__, dentry);
1737                 goto out_bad;
1738         }
1739
1740         if (nfs_verifier_is_delegated(dentry))
1741                 return nfs_lookup_revalidate_delegated(dir, dentry, inode);
1742
1743         /* Force a full look up iff the parent directory has changed */
1744         if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) &&
1745             nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) {
1746                 error = nfs_lookup_verify_inode(inode, flags);
1747                 if (error) {
1748                         if (error == -ESTALE)
1749                                 nfs_mark_dir_for_revalidate(dir);
1750                         goto out_bad;
1751                 }
1752                 goto out_valid;
1753         }
1754
1755         if (flags & LOOKUP_RCU)
1756                 return -ECHILD;
1757
1758         if (NFS_STALE(inode))
1759                 goto out_bad;
1760
1761         return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);
1762 out_valid:
1763         return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
1764 out_bad:
1765         if (flags & LOOKUP_RCU)
1766                 return -ECHILD;
1767         return nfs_lookup_revalidate_done(dir, dentry, inode, 0);
1768 }
1769
1770 static int
1771 __nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags,
1772                         int (*reval)(struct inode *, struct dentry *, unsigned int))
1773 {
1774         struct dentry *parent;
1775         struct inode *dir;
1776         int ret;
1777
1778         if (flags & LOOKUP_RCU) {
1779                 parent = READ_ONCE(dentry->d_parent);
1780                 dir = d_inode_rcu(parent);
1781                 if (!dir)
1782                         return -ECHILD;
1783                 ret = reval(dir, dentry, flags);
1784                 if (parent != READ_ONCE(dentry->d_parent))
1785                         return -ECHILD;
1786         } else {
1787                 parent = dget_parent(dentry);
1788                 ret = reval(d_inode(parent), dentry, flags);
1789                 dput(parent);
1790         }
1791         return ret;
1792 }
1793
1794 static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
1795 {
1796         return __nfs_lookup_revalidate(dentry, flags, nfs_do_lookup_revalidate);
1797 }
1798
1799 /*
1800  * A weaker form of d_revalidate for revalidating just the d_inode(dentry)
1801  * when we don't really care about the dentry name. This is called when a
1802  * pathwalk ends on a dentry that was not found via a normal lookup in the
1803  * parent dir (e.g.: ".", "..", procfs symlinks or mountpoint traversals).
1804  *
1805  * In this situation, we just want to verify that the inode itself is OK
1806  * since the dentry might have changed on the server.
1807  */
1808 static int nfs_weak_revalidate(struct dentry *dentry, unsigned int flags)
1809 {
1810         struct inode *inode = d_inode(dentry);
1811         int error = 0;
1812
1813         /*
1814          * I believe we can only get a negative dentry here in the case of a
1815          * procfs-style symlink. Just assume it's correct for now, but we may
1816          * eventually need to do something more here.
1817          */
1818         if (!inode) {
1819                 dfprintk(LOOKUPCACHE, "%s: %pd2 has negative inode\n",
1820                                 __func__, dentry);
1821                 return 1;
1822         }
1823
1824         if (is_bad_inode(inode)) {
1825                 dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
1826                                 __func__, dentry);
1827                 return 0;
1828         }
1829
1830         error = nfs_lookup_verify_inode(inode, flags);
1831         dfprintk(LOOKUPCACHE, "NFS: %s: inode %lu is %s\n",
1832                         __func__, inode->i_ino, error ? "invalid" : "valid");
1833         return !error;
1834 }
1835
1836 /*
1837  * This is called from dput() when d_count is going to 0.
1838  */
1839 static int nfs_dentry_delete(const struct dentry *dentry)
1840 {
1841         dfprintk(VFS, "NFS: dentry_delete(%pd2, %x)\n",
1842                 dentry, dentry->d_flags);
1843
1844         /* Unhash any dentry with a stale inode */
1845         if (d_really_is_positive(dentry) && NFS_STALE(d_inode(dentry)))
1846                 return 1;
1847
1848         if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1849                 /* Unhash it, so that ->d_iput() would be called */
1850                 return 1;
1851         }
1852         if (!(dentry->d_sb->s_flags & SB_ACTIVE)) {
1853                 /* Unhash it, so that ancestors of killed async unlink
1854                  * files will be cleaned up during umount */
1855                 return 1;
1856         }
1857         return 0;
1858
1859 }
1860
1861 /* Ensure that we revalidate inode->i_nlink */
1862 static void nfs_drop_nlink(struct inode *inode)
1863 {
1864         spin_lock(&inode->i_lock);
1865         /* drop the inode if we're reasonably sure this is the last link */
1866         if (inode->i_nlink > 0)
1867                 drop_nlink(inode);
1868         NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter();
1869         nfs_set_cache_invalid(
1870                 inode, NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME |
1871                                NFS_INO_INVALID_NLINK);
1872         spin_unlock(&inode->i_lock);
1873 }
1874
1875 /*
1876  * Called when the dentry loses inode.
1877  * We use it to clean up silly-renamed files.
1878  */
1879 static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
1880 {
1881         if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1882                 nfs_complete_unlink(dentry, inode);
1883                 nfs_drop_nlink(inode);
1884         }
1885         iput(inode);
1886 }
1887
1888 static void nfs_d_release(struct dentry *dentry)
1889 {
1890         /* free cached devname value, if it survived that far */
1891         if (unlikely(dentry->d_fsdata)) {
1892                 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
1893                         WARN_ON(1);
1894                 else
1895                         kfree(dentry->d_fsdata);
1896         }
1897 }
1898
1899 const struct dentry_operations nfs_dentry_operations = {
1900         .d_revalidate   = nfs_lookup_revalidate,
1901         .d_weak_revalidate      = nfs_weak_revalidate,
1902         .d_delete       = nfs_dentry_delete,
1903         .d_iput         = nfs_dentry_iput,
1904         .d_automount    = nfs_d_automount,
1905         .d_release      = nfs_d_release,
1906 };
1907 EXPORT_SYMBOL_GPL(nfs_dentry_operations);
1908
1909 struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
1910 {
1911         struct dentry *res;
1912         struct inode *inode = NULL;
1913         struct nfs_fh *fhandle = NULL;
1914         struct nfs_fattr *fattr = NULL;
1915         unsigned long dir_verifier;
1916         int error;
1917
1918         dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry);
1919         nfs_inc_stats(dir, NFSIOS_VFSLOOKUP);
1920
1921         if (unlikely(dentry->d_name.len > NFS_SERVER(dir)->namelen))
1922                 return ERR_PTR(-ENAMETOOLONG);
1923
1924         /*
1925          * If we're doing an exclusive create, optimize away the lookup
1926          * but don't hash the dentry.
1927          */
1928         if (nfs_is_exclusive_create(dir, flags) || flags & LOOKUP_RENAME_TARGET)
1929                 return NULL;
1930
1931         res = ERR_PTR(-ENOMEM);
1932         fhandle = nfs_alloc_fhandle();
1933         fattr = nfs_alloc_fattr_with_label(NFS_SERVER(dir));
1934         if (fhandle == NULL || fattr == NULL)
1935                 goto out;
1936
1937         dir_verifier = nfs_save_change_attribute(dir);
1938         trace_nfs_lookup_enter(dir, dentry, flags);
1939         error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr);
1940         if (error == -ENOENT) {
1941                 if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
1942                         dir_verifier = inode_peek_iversion_raw(dir);
1943                 goto no_entry;
1944         }
1945         if (error < 0) {
1946                 res = ERR_PTR(error);
1947                 goto out;
1948         }
1949         inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
1950         res = ERR_CAST(inode);
1951         if (IS_ERR(res))
1952                 goto out;
1953
1954         /* Notify readdir to use READDIRPLUS */
1955         nfs_lookup_advise_force_readdirplus(dir, flags);
1956
1957 no_entry:
1958         res = d_splice_alias(inode, dentry);
1959         if (res != NULL) {
1960                 if (IS_ERR(res))
1961                         goto out;
1962                 dentry = res;
1963         }
1964         nfs_set_verifier(dentry, dir_verifier);
1965 out:
1966         trace_nfs_lookup_exit(dir, dentry, flags, PTR_ERR_OR_ZERO(res));
1967         nfs_free_fattr(fattr);
1968         nfs_free_fhandle(fhandle);
1969         return res;
1970 }
1971 EXPORT_SYMBOL_GPL(nfs_lookup);
1972
1973 void nfs_d_prune_case_insensitive_aliases(struct inode *inode)
1974 {
1975         /* Case insensitive server? Revalidate dentries */
1976         if (inode && nfs_server_capable(inode, NFS_CAP_CASE_INSENSITIVE))
1977                 d_prune_aliases(inode);
1978 }
1979 EXPORT_SYMBOL_GPL(nfs_d_prune_case_insensitive_aliases);
1980
1981 #if IS_ENABLED(CONFIG_NFS_V4)
1982 static int nfs4_lookup_revalidate(struct dentry *, unsigned int);
1983
1984 const struct dentry_operations nfs4_dentry_operations = {
1985         .d_revalidate   = nfs4_lookup_revalidate,
1986         .d_weak_revalidate      = nfs_weak_revalidate,
1987         .d_delete       = nfs_dentry_delete,
1988         .d_iput         = nfs_dentry_iput,
1989         .d_automount    = nfs_d_automount,
1990         .d_release      = nfs_d_release,
1991 };
1992 EXPORT_SYMBOL_GPL(nfs4_dentry_operations);
1993
1994 static fmode_t flags_to_mode(int flags)
1995 {
1996         fmode_t res = (__force fmode_t)flags & FMODE_EXEC;
1997         if ((flags & O_ACCMODE) != O_WRONLY)
1998                 res |= FMODE_READ;
1999         if ((flags & O_ACCMODE) != O_RDONLY)
2000                 res |= FMODE_WRITE;
2001         return res;
2002 }
2003
2004 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp)
2005 {
2006         return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp);
2007 }
2008
2009 static int do_open(struct inode *inode, struct file *filp)
2010 {
2011         nfs_fscache_open_file(inode, filp);
2012         return 0;
2013 }
2014
2015 static int nfs_finish_open(struct nfs_open_context *ctx,
2016                            struct dentry *dentry,
2017                            struct file *file, unsigned open_flags)
2018 {
2019         int err;
2020
2021         err = finish_open(file, dentry, do_open);
2022         if (err)
2023                 goto out;
2024         if (S_ISREG(file->f_path.dentry->d_inode->i_mode))
2025                 nfs_file_set_open_context(file, ctx);
2026         else
2027                 err = -EOPENSTALE;
2028 out:
2029         return err;
2030 }
2031
2032 int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
2033                     struct file *file, unsigned open_flags,
2034                     umode_t mode)
2035 {
2036         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
2037         struct nfs_open_context *ctx;
2038         struct dentry *res;
2039         struct iattr attr = { .ia_valid = ATTR_OPEN };
2040         struct inode *inode;
2041         unsigned int lookup_flags = 0;
2042         unsigned long dir_verifier;
2043         bool switched = false;
2044         int created = 0;
2045         int err;
2046
2047         /* Expect a negative dentry */
2048         BUG_ON(d_inode(dentry));
2049
2050         dfprintk(VFS, "NFS: atomic_open(%s/%lu), %pd\n",
2051                         dir->i_sb->s_id, dir->i_ino, dentry);
2052
2053         err = nfs_check_flags(open_flags);
2054         if (err)
2055                 return err;
2056
2057         /* NFS only supports OPEN on regular files */
2058         if ((open_flags & O_DIRECTORY)) {
2059                 if (!d_in_lookup(dentry)) {
2060                         /*
2061                          * Hashed negative dentry with O_DIRECTORY: dentry was
2062                          * revalidated and is fine, no need to perform lookup
2063                          * again
2064                          */
2065                         return -ENOENT;
2066                 }
2067                 lookup_flags = LOOKUP_OPEN|LOOKUP_DIRECTORY;
2068                 goto no_open;
2069         }
2070
2071         if (dentry->d_name.len > NFS_SERVER(dir)->namelen)
2072                 return -ENAMETOOLONG;
2073
2074         if (open_flags & O_CREAT) {
2075                 struct nfs_server *server = NFS_SERVER(dir);
2076
2077                 if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
2078                         mode &= ~current_umask();
2079
2080                 attr.ia_valid |= ATTR_MODE;
2081                 attr.ia_mode = mode;
2082         }
2083         if (open_flags & O_TRUNC) {
2084                 attr.ia_valid |= ATTR_SIZE;
2085                 attr.ia_size = 0;
2086         }
2087
2088         if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) {
2089                 d_drop(dentry);
2090                 switched = true;
2091                 dentry = d_alloc_parallel(dentry->d_parent,
2092                                           &dentry->d_name, &wq);
2093                 if (IS_ERR(dentry))
2094                         return PTR_ERR(dentry);
2095                 if (unlikely(!d_in_lookup(dentry)))
2096                         return finish_no_open(file, dentry);
2097         }
2098
2099         ctx = create_nfs_open_context(dentry, open_flags, file);
2100         err = PTR_ERR(ctx);
2101         if (IS_ERR(ctx))
2102                 goto out;
2103
2104         trace_nfs_atomic_open_enter(dir, ctx, open_flags);
2105         inode = NFS_PROTO(dir)->open_context(dir, ctx, open_flags, &attr, &created);
2106         if (created)
2107                 file->f_mode |= FMODE_CREATED;
2108         if (IS_ERR(inode)) {
2109                 err = PTR_ERR(inode);
2110                 trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
2111                 put_nfs_open_context(ctx);
2112                 d_drop(dentry);
2113                 switch (err) {
2114                 case -ENOENT:
2115                         d_splice_alias(NULL, dentry);
2116                         if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
2117                                 dir_verifier = inode_peek_iversion_raw(dir);
2118                         else
2119                                 dir_verifier = nfs_save_change_attribute(dir);
2120                         nfs_set_verifier(dentry, dir_verifier);
2121                         break;
2122                 case -EISDIR:
2123                 case -ENOTDIR:
2124                         goto no_open;
2125                 case -ELOOP:
2126                         if (!(open_flags & O_NOFOLLOW))
2127                                 goto no_open;
2128                         break;
2129                         /* case -EINVAL: */
2130                 default:
2131                         break;
2132                 }
2133                 goto out;
2134         }
2135
2136         err = nfs_finish_open(ctx, ctx->dentry, file, open_flags);
2137         trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
2138         put_nfs_open_context(ctx);
2139 out:
2140         if (unlikely(switched)) {
2141                 d_lookup_done(dentry);
2142                 dput(dentry);
2143         }
2144         return err;
2145
2146 no_open:
2147         res = nfs_lookup(dir, dentry, lookup_flags);
2148         if (!res) {
2149                 inode = d_inode(dentry);
2150                 if ((lookup_flags & LOOKUP_DIRECTORY) && inode &&
2151                     !(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
2152                         res = ERR_PTR(-ENOTDIR);
2153                 else if (inode && S_ISREG(inode->i_mode))
2154                         res = ERR_PTR(-EOPENSTALE);
2155         } else if (!IS_ERR(res)) {
2156                 inode = d_inode(res);
2157                 if ((lookup_flags & LOOKUP_DIRECTORY) && inode &&
2158                     !(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) {
2159                         dput(res);
2160                         res = ERR_PTR(-ENOTDIR);
2161                 } else if (inode && S_ISREG(inode->i_mode)) {
2162                         dput(res);
2163                         res = ERR_PTR(-EOPENSTALE);
2164                 }
2165         }
2166         if (switched) {
2167                 d_lookup_done(dentry);
2168                 if (!res)
2169                         res = dentry;
2170                 else
2171                         dput(dentry);
2172         }
2173         if (IS_ERR(res))
2174                 return PTR_ERR(res);
2175         return finish_no_open(file, res);
2176 }
2177 EXPORT_SYMBOL_GPL(nfs_atomic_open);
2178
2179 static int
2180 nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
2181                           unsigned int flags)
2182 {
2183         struct inode *inode;
2184
2185         if (!(flags & LOOKUP_OPEN) || (flags & LOOKUP_DIRECTORY))
2186                 goto full_reval;
2187         if (d_mountpoint(dentry))
2188                 goto full_reval;
2189
2190         inode = d_inode(dentry);
2191
2192         /* We can't create new files in nfs_open_revalidate(), so we
2193          * optimize away revalidation of negative dentries.
2194          */
2195         if (inode == NULL)
2196                 goto full_reval;
2197
2198         if (nfs_verifier_is_delegated(dentry))
2199                 return nfs_lookup_revalidate_delegated(dir, dentry, inode);
2200
2201         /* NFS only supports OPEN on regular files */
2202         if (!S_ISREG(inode->i_mode))
2203                 goto full_reval;
2204
2205         /* We cannot do exclusive creation on a positive dentry */
2206         if (flags & (LOOKUP_EXCL | LOOKUP_REVAL))
2207                 goto reval_dentry;
2208
2209         /* Check if the directory changed */
2210         if (!nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU))
2211                 goto reval_dentry;
2212
2213         /* Let f_op->open() actually open (and revalidate) the file */
2214         return 1;
2215 reval_dentry:
2216         if (flags & LOOKUP_RCU)
2217                 return -ECHILD;
2218         return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);
2219
2220 full_reval:
2221         return nfs_do_lookup_revalidate(dir, dentry, flags);
2222 }
2223
2224 static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags)
2225 {
2226         return __nfs_lookup_revalidate(dentry, flags,
2227                         nfs4_do_lookup_revalidate);
2228 }
2229
2230 #endif /* CONFIG_NFSV4 */
2231
2232 struct dentry *
2233 nfs_add_or_obtain(struct dentry *dentry, struct nfs_fh *fhandle,
2234                                 struct nfs_fattr *fattr)
2235 {
2236         struct dentry *parent = dget_parent(dentry);
2237         struct inode *dir = d_inode(parent);
2238         struct inode *inode;
2239         struct dentry *d;
2240         int error;
2241
2242         d_drop(dentry);
2243
2244         if (fhandle->size == 0) {
2245                 error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr);
2246                 if (error)
2247                         goto out_error;
2248         }
2249         nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
2250         if (!(fattr->valid & NFS_ATTR_FATTR)) {
2251                 struct nfs_server *server = NFS_SB(dentry->d_sb);
2252                 error = server->nfs_client->rpc_ops->getattr(server, fhandle,
2253                                 fattr, NULL);
2254                 if (error < 0)
2255                         goto out_error;
2256         }
2257         inode = nfs_fhget(dentry->d_sb, fhandle, fattr);
2258         d = d_splice_alias(inode, dentry);
2259 out:
2260         dput(parent);
2261         return d;
2262 out_error:
2263         d = ERR_PTR(error);
2264         goto out;
2265 }
2266 EXPORT_SYMBOL_GPL(nfs_add_or_obtain);
2267
2268 /*
2269  * Code common to create, mkdir, and mknod.
2270  */
2271 int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle,
2272                                 struct nfs_fattr *fattr)
2273 {
2274         struct dentry *d;
2275
2276         d = nfs_add_or_obtain(dentry, fhandle, fattr);
2277         if (IS_ERR(d))
2278                 return PTR_ERR(d);
2279
2280         /* Callers don't care */
2281         dput(d);
2282         return 0;
2283 }
2284 EXPORT_SYMBOL_GPL(nfs_instantiate);
2285
2286 /*
2287  * Following a failed create operation, we drop the dentry rather
2288  * than retain a negative dentry. This avoids a problem in the event
2289  * that the operation succeeded on the server, but an error in the
2290  * reply path made it appear to have failed.
2291  */
2292 int nfs_create(struct user_namespace *mnt_userns, struct inode *dir,
2293                struct dentry *dentry, umode_t mode, bool excl)
2294 {
2295         struct iattr attr;
2296         int open_flags = excl ? O_CREAT | O_EXCL : O_CREAT;
2297         int error;
2298
2299         dfprintk(VFS, "NFS: create(%s/%lu), %pd\n",
2300                         dir->i_sb->s_id, dir->i_ino, dentry);
2301
2302         attr.ia_mode = mode;
2303         attr.ia_valid = ATTR_MODE;
2304
2305         trace_nfs_create_enter(dir, dentry, open_flags);
2306         error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
2307         trace_nfs_create_exit(dir, dentry, open_flags, error);
2308         if (error != 0)
2309                 goto out_err;
2310         return 0;
2311 out_err:
2312         d_drop(dentry);
2313         return error;
2314 }
2315 EXPORT_SYMBOL_GPL(nfs_create);
2316
2317 /*
2318  * See comments for nfs_proc_create regarding failed operations.
2319  */
2320 int
2321 nfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
2322           struct dentry *dentry, umode_t mode, dev_t rdev)
2323 {
2324         struct iattr attr;
2325         int status;
2326
2327         dfprintk(VFS, "NFS: mknod(%s/%lu), %pd\n",
2328                         dir->i_sb->s_id, dir->i_ino, dentry);
2329
2330         attr.ia_mode = mode;
2331         attr.ia_valid = ATTR_MODE;
2332
2333         trace_nfs_mknod_enter(dir, dentry);
2334         status = NFS_PROTO(dir)->mknod(dir, dentry, &attr, rdev);
2335         trace_nfs_mknod_exit(dir, dentry, status);
2336         if (status != 0)
2337                 goto out_err;
2338         return 0;
2339 out_err:
2340         d_drop(dentry);
2341         return status;
2342 }
2343 EXPORT_SYMBOL_GPL(nfs_mknod);
2344
2345 /*
2346  * See comments for nfs_proc_create regarding failed operations.
2347  */
2348 int nfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
2349               struct dentry *dentry, umode_t mode)
2350 {
2351         struct iattr attr;
2352         int error;
2353
2354         dfprintk(VFS, "NFS: mkdir(%s/%lu), %pd\n",
2355                         dir->i_sb->s_id, dir->i_ino, dentry);
2356
2357         attr.ia_valid = ATTR_MODE;
2358         attr.ia_mode = mode | S_IFDIR;
2359
2360         trace_nfs_mkdir_enter(dir, dentry);
2361         error = NFS_PROTO(dir)->mkdir(dir, dentry, &attr);
2362         trace_nfs_mkdir_exit(dir, dentry, error);
2363         if (error != 0)
2364                 goto out_err;
2365         return 0;
2366 out_err:
2367         d_drop(dentry);
2368         return error;
2369 }
2370 EXPORT_SYMBOL_GPL(nfs_mkdir);
2371
2372 static void nfs_dentry_handle_enoent(struct dentry *dentry)
2373 {
2374         if (simple_positive(dentry))
2375                 d_delete(dentry);
2376 }
2377
2378 static void nfs_dentry_remove_handle_error(struct inode *dir,
2379                                            struct dentry *dentry, int error)
2380 {
2381         switch (error) {
2382         case -ENOENT:
2383                 d_delete(dentry);
2384                 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
2385                 break;
2386         case 0:
2387                 nfs_d_prune_case_insensitive_aliases(d_inode(dentry));
2388                 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
2389         }
2390 }
2391
2392 int nfs_rmdir(struct inode *dir, struct dentry *dentry)
2393 {
2394         int error;
2395
2396         dfprintk(VFS, "NFS: rmdir(%s/%lu), %pd\n",
2397                         dir->i_sb->s_id, dir->i_ino, dentry);
2398
2399         trace_nfs_rmdir_enter(dir, dentry);
2400         if (d_really_is_positive(dentry)) {
2401                 down_write(&NFS_I(d_inode(dentry))->rmdir_sem);
2402                 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
2403                 /* Ensure the VFS deletes this inode */
2404                 switch (error) {
2405                 case 0:
2406                         clear_nlink(d_inode(dentry));
2407                         break;
2408                 case -ENOENT:
2409                         nfs_dentry_handle_enoent(dentry);
2410                 }
2411                 up_write(&NFS_I(d_inode(dentry))->rmdir_sem);
2412         } else
2413                 error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
2414         nfs_dentry_remove_handle_error(dir, dentry, error);
2415         trace_nfs_rmdir_exit(dir, dentry, error);
2416
2417         return error;
2418 }
2419 EXPORT_SYMBOL_GPL(nfs_rmdir);
2420
2421 /*
2422  * Remove a file after making sure there are no pending writes,
2423  * and after checking that the file has only one user.
2424  *
2425  * We invalidate the attribute cache and free the inode prior to the operation
2426  * to avoid possible races if the server reuses the inode.
2427  */
2428 static int nfs_safe_remove(struct dentry *dentry)
2429 {
2430         struct inode *dir = d_inode(dentry->d_parent);
2431         struct inode *inode = d_inode(dentry);
2432         int error = -EBUSY;
2433
2434         dfprintk(VFS, "NFS: safe_remove(%pd2)\n", dentry);
2435
2436         /* If the dentry was sillyrenamed, we simply call d_delete() */
2437         if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
2438                 error = 0;
2439                 goto out;
2440         }
2441
2442         trace_nfs_remove_enter(dir, dentry);
2443         if (inode != NULL) {
2444                 error = NFS_PROTO(dir)->remove(dir, dentry);
2445                 if (error == 0)
2446                         nfs_drop_nlink(inode);
2447         } else
2448                 error = NFS_PROTO(dir)->remove(dir, dentry);
2449         if (error == -ENOENT)
2450                 nfs_dentry_handle_enoent(dentry);
2451         trace_nfs_remove_exit(dir, dentry, error);
2452 out:
2453         return error;
2454 }
2455
2456 /*  We do silly rename. In case sillyrename() returns -EBUSY, the inode
2457  *  belongs to an active ".nfs..." file and we return -EBUSY.
2458  *
2459  *  If sillyrename() returns 0, we do nothing, otherwise we unlink.
2460  */
2461 int nfs_unlink(struct inode *dir, struct dentry *dentry)
2462 {
2463         int error;
2464         int need_rehash = 0;
2465
2466         dfprintk(VFS, "NFS: unlink(%s/%lu, %pd)\n", dir->i_sb->s_id,
2467                 dir->i_ino, dentry);
2468
2469         trace_nfs_unlink_enter(dir, dentry);
2470         spin_lock(&dentry->d_lock);
2471         if (d_count(dentry) > 1 && !test_bit(NFS_INO_PRESERVE_UNLINKED,
2472                                              &NFS_I(d_inode(dentry))->flags)) {
2473                 spin_unlock(&dentry->d_lock);
2474                 /* Start asynchronous writeout of the inode */
2475                 write_inode_now(d_inode(dentry), 0);
2476                 error = nfs_sillyrename(dir, dentry);
2477                 goto out;
2478         }
2479         if (!d_unhashed(dentry)) {
2480                 __d_drop(dentry);
2481                 need_rehash = 1;
2482         }
2483         spin_unlock(&dentry->d_lock);
2484         error = nfs_safe_remove(dentry);
2485         nfs_dentry_remove_handle_error(dir, dentry, error);
2486         if (need_rehash)
2487                 d_rehash(dentry);
2488 out:
2489         trace_nfs_unlink_exit(dir, dentry, error);
2490         return error;
2491 }
2492 EXPORT_SYMBOL_GPL(nfs_unlink);
2493
2494 /*
2495  * To create a symbolic link, most file systems instantiate a new inode,
2496  * add a page to it containing the path, then write it out to the disk
2497  * using prepare_write/commit_write.
2498  *
2499  * Unfortunately the NFS client can't create the in-core inode first
2500  * because it needs a file handle to create an in-core inode (see
2501  * fs/nfs/inode.c:nfs_fhget).  We only have a file handle *after* the
2502  * symlink request has completed on the server.
2503  *
2504  * So instead we allocate a raw page, copy the symname into it, then do
2505  * the SYMLINK request with the page as the buffer.  If it succeeds, we
2506  * now have a new file handle and can instantiate an in-core NFS inode
2507  * and move the raw page into its mapping.
2508  */
2509 int nfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
2510                 struct dentry *dentry, const char *symname)
2511 {
2512         struct page *page;
2513         char *kaddr;
2514         struct iattr attr;
2515         unsigned int pathlen = strlen(symname);
2516         int error;
2517
2518         dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s)\n", dir->i_sb->s_id,
2519                 dir->i_ino, dentry, symname);
2520
2521         if (pathlen > PAGE_SIZE)
2522                 return -ENAMETOOLONG;
2523
2524         attr.ia_mode = S_IFLNK | S_IRWXUGO;
2525         attr.ia_valid = ATTR_MODE;
2526
2527         page = alloc_page(GFP_USER);
2528         if (!page)
2529                 return -ENOMEM;
2530
2531         kaddr = page_address(page);
2532         memcpy(kaddr, symname, pathlen);
2533         if (pathlen < PAGE_SIZE)
2534                 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen);
2535
2536         trace_nfs_symlink_enter(dir, dentry);
2537         error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr);
2538         trace_nfs_symlink_exit(dir, dentry, error);
2539         if (error != 0) {
2540                 dfprintk(VFS, "NFS: symlink(%s/%lu, %pd, %s) error %d\n",
2541                         dir->i_sb->s_id, dir->i_ino,
2542                         dentry, symname, error);
2543                 d_drop(dentry);
2544                 __free_page(page);
2545                 return error;
2546         }
2547
2548         nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
2549
2550         /*
2551          * No big deal if we can't add this page to the page cache here.
2552          * READLINK will get the missing page from the server if needed.
2553          */
2554         if (!add_to_page_cache_lru(page, d_inode(dentry)->i_mapping, 0,
2555                                                         GFP_KERNEL)) {
2556                 SetPageUptodate(page);
2557                 unlock_page(page);
2558                 /*
2559                  * add_to_page_cache_lru() grabs an extra page refcount.
2560                  * Drop it here to avoid leaking this page later.
2561                  */
2562                 put_page(page);
2563         } else
2564                 __free_page(page);
2565
2566         return 0;
2567 }
2568 EXPORT_SYMBOL_GPL(nfs_symlink);
2569
2570 int
2571 nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
2572 {
2573         struct inode *inode = d_inode(old_dentry);
2574         int error;
2575
2576         dfprintk(VFS, "NFS: link(%pd2 -> %pd2)\n",
2577                 old_dentry, dentry);
2578
2579         trace_nfs_link_enter(inode, dir, dentry);
2580         d_drop(dentry);
2581         if (S_ISREG(inode->i_mode))
2582                 nfs_sync_inode(inode);
2583         error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
2584         if (error == 0) {
2585                 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
2586                 ihold(inode);
2587                 d_add(dentry, inode);
2588         }
2589         trace_nfs_link_exit(inode, dir, dentry, error);
2590         return error;
2591 }
2592 EXPORT_SYMBOL_GPL(nfs_link);
2593
2594 /*
2595  * RENAME
2596  * FIXME: Some nfsds, like the Linux user space nfsd, may generate a
2597  * different file handle for the same inode after a rename (e.g. when
2598  * moving to a different directory). A fail-safe method to do so would
2599  * be to look up old_dir/old_name, create a link to new_dir/new_name and
2600  * rename the old file using the sillyrename stuff. This way, the original
2601  * file in old_dir will go away when the last process iput()s the inode.
2602  *
2603  * FIXED.
2604  *
2605  * It actually works quite well. One needs to have the possibility for
2606  * at least one ".nfs..." file in each directory the file ever gets
2607  * moved or linked to which happens automagically with the new
2608  * implementation that only depends on the dcache stuff instead of
2609  * using the inode layer
2610  *
2611  * Unfortunately, things are a little more complicated than indicated
2612  * above. For a cross-directory move, we want to make sure we can get
2613  * rid of the old inode after the operation.  This means there must be
2614  * no pending writes (if it's a file), and the use count must be 1.
2615  * If these conditions are met, we can drop the dentries before doing
2616  * the rename.
2617  */
2618 int nfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
2619                struct dentry *old_dentry, struct inode *new_dir,
2620                struct dentry *new_dentry, unsigned int flags)
2621 {
2622         struct inode *old_inode = d_inode(old_dentry);
2623         struct inode *new_inode = d_inode(new_dentry);
2624         struct dentry *dentry = NULL, *rehash = NULL;
2625         struct rpc_task *task;
2626         int error = -EBUSY;
2627
2628         if (flags)
2629                 return -EINVAL;
2630
2631         dfprintk(VFS, "NFS: rename(%pd2 -> %pd2, ct=%d)\n",
2632                  old_dentry, new_dentry,
2633                  d_count(new_dentry));
2634
2635         trace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry);
2636         /*
2637          * For non-directories, check whether the target is busy and if so,
2638          * make a copy of the dentry and then do a silly-rename. If the
2639          * silly-rename succeeds, the copied dentry is hashed and becomes
2640          * the new target.
2641          */
2642         if (new_inode && !S_ISDIR(new_inode->i_mode)) {
2643                 /*
2644                  * To prevent any new references to the target during the
2645                  * rename, we unhash the dentry in advance.
2646                  */
2647                 if (!d_unhashed(new_dentry)) {
2648                         d_drop(new_dentry);
2649                         rehash = new_dentry;
2650                 }
2651
2652                 if (d_count(new_dentry) > 2) {
2653                         int err;
2654
2655                         /* copy the target dentry's name */
2656                         dentry = d_alloc(new_dentry->d_parent,
2657                                          &new_dentry->d_name);
2658                         if (!dentry)
2659                                 goto out;
2660
2661                         /* silly-rename the existing target ... */
2662                         err = nfs_sillyrename(new_dir, new_dentry);
2663                         if (err)
2664                                 goto out;
2665
2666                         new_dentry = dentry;
2667                         rehash = NULL;
2668                         new_inode = NULL;
2669                 }
2670         }
2671
2672         if (S_ISREG(old_inode->i_mode))
2673                 nfs_sync_inode(old_inode);
2674         task = nfs_async_rename(old_dir, new_dir, old_dentry, new_dentry, NULL);
2675         if (IS_ERR(task)) {
2676                 error = PTR_ERR(task);
2677                 goto out;
2678         }
2679
2680         error = rpc_wait_for_completion_task(task);
2681         if (error != 0) {
2682                 ((struct nfs_renamedata *)task->tk_calldata)->cancelled = 1;
2683                 /* Paired with the atomic_dec_and_test() barrier in rpc_do_put_task() */
2684                 smp_wmb();
2685         } else
2686                 error = task->tk_status;
2687         rpc_put_task(task);
2688         /* Ensure the inode attributes are revalidated */
2689         if (error == 0) {
2690                 spin_lock(&old_inode->i_lock);
2691                 NFS_I(old_inode)->attr_gencount = nfs_inc_attr_generation_counter();
2692                 nfs_set_cache_invalid(old_inode, NFS_INO_INVALID_CHANGE |
2693                                                          NFS_INO_INVALID_CTIME |
2694                                                          NFS_INO_REVAL_FORCED);
2695                 spin_unlock(&old_inode->i_lock);
2696         }
2697 out:
2698         if (rehash)
2699                 d_rehash(rehash);
2700         trace_nfs_rename_exit(old_dir, old_dentry,
2701                         new_dir, new_dentry, error);
2702         if (!error) {
2703                 if (new_inode != NULL)
2704                         nfs_drop_nlink(new_inode);
2705                 /*
2706                  * The d_move() should be here instead of in an async RPC completion
2707                  * handler because we need the proper locks to move the dentry.  If
2708                  * we're interrupted by a signal, the async RPC completion handler
2709                  * should mark the directories for revalidation.
2710                  */
2711                 d_move(old_dentry, new_dentry);
2712                 nfs_set_verifier(old_dentry,
2713                                         nfs_save_change_attribute(new_dir));
2714         } else if (error == -ENOENT)
2715                 nfs_dentry_handle_enoent(old_dentry);
2716
2717         /* new dentry created? */
2718         if (dentry)
2719                 dput(dentry);
2720         return error;
2721 }
2722 EXPORT_SYMBOL_GPL(nfs_rename);
2723
2724 static DEFINE_SPINLOCK(nfs_access_lru_lock);
2725 static LIST_HEAD(nfs_access_lru_list);
2726 static atomic_long_t nfs_access_nr_entries;
2727
2728 static unsigned long nfs_access_max_cachesize = 4*1024*1024;
2729 module_param(nfs_access_max_cachesize, ulong, 0644);
2730 MODULE_PARM_DESC(nfs_access_max_cachesize, "NFS access maximum total cache length");
2731
2732 static void nfs_access_free_entry(struct nfs_access_entry *entry)
2733 {
2734         put_group_info(entry->group_info);
2735         kfree_rcu(entry, rcu_head);
2736         smp_mb__before_atomic();
2737         atomic_long_dec(&nfs_access_nr_entries);
2738         smp_mb__after_atomic();
2739 }
2740
2741 static void nfs_access_free_list(struct list_head *head)
2742 {
2743         struct nfs_access_entry *cache;
2744
2745         while (!list_empty(head)) {
2746                 cache = list_entry(head->next, struct nfs_access_entry, lru);
2747                 list_del(&cache->lru);
2748                 nfs_access_free_entry(cache);
2749         }
2750 }
2751
2752 static unsigned long
2753 nfs_do_access_cache_scan(unsigned int nr_to_scan)
2754 {
2755         LIST_HEAD(head);
2756         struct nfs_inode *nfsi, *next;
2757         struct nfs_access_entry *cache;
2758         long freed = 0;
2759
2760         spin_lock(&nfs_access_lru_lock);
2761         list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) {
2762                 struct inode *inode;
2763
2764                 if (nr_to_scan-- == 0)
2765                         break;
2766                 inode = &nfsi->vfs_inode;
2767                 spin_lock(&inode->i_lock);
2768                 if (list_empty(&nfsi->access_cache_entry_lru))
2769                         goto remove_lru_entry;
2770                 cache = list_entry(nfsi->access_cache_entry_lru.next,
2771                                 struct nfs_access_entry, lru);
2772                 list_move(&cache->lru, &head);
2773                 rb_erase(&cache->rb_node, &nfsi->access_cache);
2774                 freed++;
2775                 if (!list_empty(&nfsi->access_cache_entry_lru))
2776                         list_move_tail(&nfsi->access_cache_inode_lru,
2777                                         &nfs_access_lru_list);
2778                 else {
2779 remove_lru_entry:
2780                         list_del_init(&nfsi->access_cache_inode_lru);
2781                         smp_mb__before_atomic();
2782                         clear_bit(NFS_INO_ACL_LRU_SET, &nfsi->flags);
2783                         smp_mb__after_atomic();
2784                 }
2785                 spin_unlock(&inode->i_lock);
2786         }
2787         spin_unlock(&nfs_access_lru_lock);
2788         nfs_access_free_list(&head);
2789         return freed;
2790 }
2791
2792 unsigned long
2793 nfs_access_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
2794 {
2795         int nr_to_scan = sc->nr_to_scan;
2796         gfp_t gfp_mask = sc->gfp_mask;
2797
2798         if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
2799                 return SHRINK_STOP;
2800         return nfs_do_access_cache_scan(nr_to_scan);
2801 }
2802
2803
2804 unsigned long
2805 nfs_access_cache_count(struct shrinker *shrink, struct shrink_control *sc)
2806 {
2807         return vfs_pressure_ratio(atomic_long_read(&nfs_access_nr_entries));
2808 }
2809
2810 static void
2811 nfs_access_cache_enforce_limit(void)
2812 {
2813         long nr_entries = atomic_long_read(&nfs_access_nr_entries);
2814         unsigned long diff;
2815         unsigned int nr_to_scan;
2816
2817         if (nr_entries < 0 || nr_entries <= nfs_access_max_cachesize)
2818                 return;
2819         nr_to_scan = 100;
2820         diff = nr_entries - nfs_access_max_cachesize;
2821         if (diff < nr_to_scan)
2822                 nr_to_scan = diff;
2823         nfs_do_access_cache_scan(nr_to_scan);
2824 }
2825
2826 static void __nfs_access_zap_cache(struct nfs_inode *nfsi, struct list_head *head)
2827 {
2828         struct rb_root *root_node = &nfsi->access_cache;
2829         struct rb_node *n;
2830         struct nfs_access_entry *entry;
2831
2832         /* Unhook entries from the cache */
2833         while ((n = rb_first(root_node)) != NULL) {
2834                 entry = rb_entry(n, struct nfs_access_entry, rb_node);
2835                 rb_erase(n, root_node);
2836                 list_move(&entry->lru, head);
2837         }
2838         nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
2839 }
2840
2841 void nfs_access_zap_cache(struct inode *inode)
2842 {
2843         LIST_HEAD(head);
2844
2845         if (test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags) == 0)
2846                 return;
2847         /* Remove from global LRU init */
2848         spin_lock(&nfs_access_lru_lock);
2849         if (test_and_clear_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
2850                 list_del_init(&NFS_I(inode)->access_cache_inode_lru);
2851
2852         spin_lock(&inode->i_lock);
2853         __nfs_access_zap_cache(NFS_I(inode), &head);
2854         spin_unlock(&inode->i_lock);
2855         spin_unlock(&nfs_access_lru_lock);
2856         nfs_access_free_list(&head);
2857 }
2858 EXPORT_SYMBOL_GPL(nfs_access_zap_cache);
2859
2860 static int access_cmp(const struct cred *a, const struct nfs_access_entry *b)
2861 {
2862         struct group_info *ga, *gb;
2863         int g;
2864
2865         if (uid_lt(a->fsuid, b->fsuid))
2866                 return -1;
2867         if (uid_gt(a->fsuid, b->fsuid))
2868                 return 1;
2869
2870         if (gid_lt(a->fsgid, b->fsgid))
2871                 return -1;
2872         if (gid_gt(a->fsgid, b->fsgid))
2873                 return 1;
2874
2875         ga = a->group_info;
2876         gb = b->group_info;
2877         if (ga == gb)
2878                 return 0;
2879         if (ga == NULL)
2880                 return -1;
2881         if (gb == NULL)
2882                 return 1;
2883         if (ga->ngroups < gb->ngroups)
2884                 return -1;
2885         if (ga->ngroups > gb->ngroups)
2886                 return 1;
2887
2888         for (g = 0; g < ga->ngroups; g++) {
2889                 if (gid_lt(ga->gid[g], gb->gid[g]))
2890                         return -1;
2891                 if (gid_gt(ga->gid[g], gb->gid[g]))
2892                         return 1;
2893         }
2894         return 0;
2895 }
2896
2897 static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, const struct cred *cred)
2898 {
2899         struct rb_node *n = NFS_I(inode)->access_cache.rb_node;
2900
2901         while (n != NULL) {
2902                 struct nfs_access_entry *entry =
2903                         rb_entry(n, struct nfs_access_entry, rb_node);
2904                 int cmp = access_cmp(cred, entry);
2905
2906                 if (cmp < 0)
2907                         n = n->rb_left;
2908                 else if (cmp > 0)
2909                         n = n->rb_right;
2910                 else
2911                         return entry;
2912         }
2913         return NULL;
2914 }
2915
2916 static int nfs_access_get_cached_locked(struct inode *inode, const struct cred *cred, u32 *mask, bool may_block)
2917 {
2918         struct nfs_inode *nfsi = NFS_I(inode);
2919         struct nfs_access_entry *cache;
2920         bool retry = true;
2921         int err;
2922
2923         spin_lock(&inode->i_lock);
2924         for(;;) {
2925                 if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
2926                         goto out_zap;
2927                 cache = nfs_access_search_rbtree(inode, cred);
2928                 err = -ENOENT;
2929                 if (cache == NULL)
2930                         goto out;
2931                 /* Found an entry, is our attribute cache valid? */
2932                 if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
2933                         break;
2934                 if (!retry)
2935                         break;
2936                 err = -ECHILD;
2937                 if (!may_block)
2938                         goto out;
2939                 spin_unlock(&inode->i_lock);
2940                 err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
2941                 if (err)
2942                         return err;
2943                 spin_lock(&inode->i_lock);
2944                 retry = false;
2945         }
2946         *mask = cache->mask;
2947         list_move_tail(&cache->lru, &nfsi->access_cache_entry_lru);
2948         err = 0;
2949 out:
2950         spin_unlock(&inode->i_lock);
2951         return err;
2952 out_zap:
2953         spin_unlock(&inode->i_lock);
2954         nfs_access_zap_cache(inode);
2955         return -ENOENT;
2956 }
2957
2958 static int nfs_access_get_cached_rcu(struct inode *inode, const struct cred *cred, u32 *mask)
2959 {
2960         /* Only check the most recently returned cache entry,
2961          * but do it without locking.
2962          */
2963         struct nfs_inode *nfsi = NFS_I(inode);
2964         struct nfs_access_entry *cache;
2965         int err = -ECHILD;
2966         struct list_head *lh;
2967
2968         rcu_read_lock();
2969         if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)
2970                 goto out;
2971         lh = rcu_dereference(list_tail_rcu(&nfsi->access_cache_entry_lru));
2972         cache = list_entry(lh, struct nfs_access_entry, lru);
2973         if (lh == &nfsi->access_cache_entry_lru ||
2974             access_cmp(cred, cache) != 0)
2975                 cache = NULL;
2976         if (cache == NULL)
2977                 goto out;
2978         if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
2979                 goto out;
2980         *mask = cache->mask;
2981         err = 0;
2982 out:
2983         rcu_read_unlock();
2984         return err;
2985 }
2986
2987 int nfs_access_get_cached(struct inode *inode, const struct cred *cred,
2988                           u32 *mask, bool may_block)
2989 {
2990         int status;
2991
2992         status = nfs_access_get_cached_rcu(inode, cred, mask);
2993         if (status != 0)
2994                 status = nfs_access_get_cached_locked(inode, cred, mask,
2995                     may_block);
2996
2997         return status;
2998 }
2999 EXPORT_SYMBOL_GPL(nfs_access_get_cached);
3000
3001 static void nfs_access_add_rbtree(struct inode *inode,
3002                                   struct nfs_access_entry *set,
3003                                   const struct cred *cred)
3004 {
3005         struct nfs_inode *nfsi = NFS_I(inode);
3006         struct rb_root *root_node = &nfsi->access_cache;
3007         struct rb_node **p = &root_node->rb_node;
3008         struct rb_node *parent = NULL;
3009         struct nfs_access_entry *entry;
3010         int cmp;
3011
3012         spin_lock(&inode->i_lock);
3013         while (*p != NULL) {
3014                 parent = *p;
3015                 entry = rb_entry(parent, struct nfs_access_entry, rb_node);
3016                 cmp = access_cmp(cred, entry);
3017
3018                 if (cmp < 0)
3019                         p = &parent->rb_left;
3020                 else if (cmp > 0)
3021                         p = &parent->rb_right;
3022                 else
3023                         goto found;
3024         }
3025         rb_link_node(&set->rb_node, parent, p);
3026         rb_insert_color(&set->rb_node, root_node);
3027         list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
3028         spin_unlock(&inode->i_lock);
3029         return;
3030 found:
3031         rb_replace_node(parent, &set->rb_node, root_node);
3032         list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
3033         list_del(&entry->lru);
3034         spin_unlock(&inode->i_lock);
3035         nfs_access_free_entry(entry);
3036 }
3037
3038 void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set,
3039                           const struct cred *cred)
3040 {
3041         struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL);
3042         if (cache == NULL)
3043                 return;
3044         RB_CLEAR_NODE(&cache->rb_node);
3045         cache->fsuid = cred->fsuid;
3046         cache->fsgid = cred->fsgid;
3047         cache->group_info = get_group_info(cred->group_info);
3048         cache->mask = set->mask;
3049
3050         /* The above field assignments must be visible
3051          * before this item appears on the lru.  We cannot easily
3052          * use rcu_assign_pointer, so just force the memory barrier.
3053          */
3054         smp_wmb();
3055         nfs_access_add_rbtree(inode, cache, cred);
3056
3057         /* Update accounting */
3058         smp_mb__before_atomic();
3059         atomic_long_inc(&nfs_access_nr_entries);
3060         smp_mb__after_atomic();
3061
3062         /* Add inode to global LRU list */
3063         if (!test_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags)) {
3064                 spin_lock(&nfs_access_lru_lock);
3065                 if (!test_and_set_bit(NFS_INO_ACL_LRU_SET, &NFS_I(inode)->flags))
3066                         list_add_tail(&NFS_I(inode)->access_cache_inode_lru,
3067                                         &nfs_access_lru_list);
3068                 spin_unlock(&nfs_access_lru_lock);
3069         }
3070         nfs_access_cache_enforce_limit();
3071 }
3072 EXPORT_SYMBOL_GPL(nfs_access_add_cache);
3073
3074 #define NFS_MAY_READ (NFS_ACCESS_READ)
3075 #define NFS_MAY_WRITE (NFS_ACCESS_MODIFY | \
3076                 NFS_ACCESS_EXTEND | \
3077                 NFS_ACCESS_DELETE)
3078 #define NFS_FILE_MAY_WRITE (NFS_ACCESS_MODIFY | \
3079                 NFS_ACCESS_EXTEND)
3080 #define NFS_DIR_MAY_WRITE NFS_MAY_WRITE
3081 #define NFS_MAY_LOOKUP (NFS_ACCESS_LOOKUP)
3082 #define NFS_MAY_EXECUTE (NFS_ACCESS_EXECUTE)
3083 static int
3084 nfs_access_calc_mask(u32 access_result, umode_t umode)
3085 {
3086         int mask = 0;
3087
3088         if (access_result & NFS_MAY_READ)
3089                 mask |= MAY_READ;
3090         if (S_ISDIR(umode)) {
3091                 if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE)
3092                         mask |= MAY_WRITE;
3093                 if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP)
3094                         mask |= MAY_EXEC;
3095         } else if (S_ISREG(umode)) {
3096                 if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE)
3097                         mask |= MAY_WRITE;
3098                 if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE)
3099                         mask |= MAY_EXEC;
3100         } else if (access_result & NFS_MAY_WRITE)
3101                         mask |= MAY_WRITE;
3102         return mask;
3103 }
3104
3105 void nfs_access_set_mask(struct nfs_access_entry *entry, u32 access_result)
3106 {
3107         entry->mask = access_result;
3108 }
3109 EXPORT_SYMBOL_GPL(nfs_access_set_mask);
3110
3111 static int nfs_do_access(struct inode *inode, const struct cred *cred, int mask)
3112 {
3113         struct nfs_access_entry cache;
3114         bool may_block = (mask & MAY_NOT_BLOCK) == 0;
3115         int cache_mask = -1;
3116         int status;
3117
3118         trace_nfs_access_enter(inode);
3119
3120         status = nfs_access_get_cached(inode, cred, &cache.mask, may_block);
3121         if (status == 0)
3122                 goto out_cached;
3123
3124         status = -ECHILD;
3125         if (!may_block)
3126                 goto out;
3127
3128         /*
3129          * Determine which access bits we want to ask for...
3130          */
3131         cache.mask = NFS_ACCESS_READ | NFS_ACCESS_MODIFY | NFS_ACCESS_EXTEND |
3132                      nfs_access_xattr_mask(NFS_SERVER(inode));
3133         if (S_ISDIR(inode->i_mode))
3134                 cache.mask |= NFS_ACCESS_DELETE | NFS_ACCESS_LOOKUP;
3135         else
3136                 cache.mask |= NFS_ACCESS_EXECUTE;
3137         status = NFS_PROTO(inode)->access(inode, &cache, cred);
3138         if (status != 0) {
3139                 if (status == -ESTALE) {
3140                         if (!S_ISDIR(inode->i_mode))
3141                                 nfs_set_inode_stale(inode);
3142                         else
3143                                 nfs_zap_caches(inode);
3144                 }
3145                 goto out;
3146         }
3147         nfs_access_add_cache(inode, &cache, cred);
3148 out_cached:
3149         cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode);
3150         if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0)
3151                 status = -EACCES;
3152 out:
3153         trace_nfs_access_exit(inode, mask, cache_mask, status);
3154         return status;
3155 }
3156
3157 static int nfs_open_permission_mask(int openflags)
3158 {
3159         int mask = 0;
3160
3161         if (openflags & __FMODE_EXEC) {
3162                 /* ONLY check exec rights */
3163                 mask = MAY_EXEC;
3164         } else {
3165                 if ((openflags & O_ACCMODE) != O_WRONLY)
3166                         mask |= MAY_READ;
3167                 if ((openflags & O_ACCMODE) != O_RDONLY)
3168                         mask |= MAY_WRITE;
3169         }
3170
3171         return mask;
3172 }
3173
3174 int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags)
3175 {
3176         return nfs_do_access(inode, cred, nfs_open_permission_mask(openflags));
3177 }
3178 EXPORT_SYMBOL_GPL(nfs_may_open);
3179
3180 static int nfs_execute_ok(struct inode *inode, int mask)
3181 {
3182         struct nfs_server *server = NFS_SERVER(inode);
3183         int ret = 0;
3184
3185         if (S_ISDIR(inode->i_mode))
3186                 return 0;
3187         if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_MODE)) {
3188                 if (mask & MAY_NOT_BLOCK)
3189                         return -ECHILD;
3190                 ret = __nfs_revalidate_inode(server, inode);
3191         }
3192         if (ret == 0 && !execute_ok(inode))
3193                 ret = -EACCES;
3194         return ret;
3195 }
3196
3197 int nfs_permission(struct user_namespace *mnt_userns,
3198                    struct inode *inode,
3199                    int mask)
3200 {
3201         const struct cred *cred = current_cred();
3202         int res = 0;
3203
3204         nfs_inc_stats(inode, NFSIOS_VFSACCESS);
3205
3206         if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
3207                 goto out;
3208         /* Is this sys_access() ? */
3209         if (mask & (MAY_ACCESS | MAY_CHDIR))
3210                 goto force_lookup;
3211
3212         switch (inode->i_mode & S_IFMT) {
3213                 case S_IFLNK:
3214                         goto out;
3215                 case S_IFREG:
3216                         if ((mask & MAY_OPEN) &&
3217                            nfs_server_capable(inode, NFS_CAP_ATOMIC_OPEN))
3218                                 return 0;
3219                         break;
3220                 case S_IFDIR:
3221                         /*
3222                          * Optimize away all write operations, since the server
3223                          * will check permissions when we perform the op.
3224                          */
3225                         if ((mask & MAY_WRITE) && !(mask & MAY_READ))
3226                                 goto out;
3227         }
3228
3229 force_lookup:
3230         if (!NFS_PROTO(inode)->access)
3231                 goto out_notsup;
3232
3233         res = nfs_do_access(inode, cred, mask);
3234 out:
3235         if (!res && (mask & MAY_EXEC))
3236                 res = nfs_execute_ok(inode, mask);
3237
3238         dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n",
3239                 inode->i_sb->s_id, inode->i_ino, mask, res);
3240         return res;
3241 out_notsup:
3242         if (mask & MAY_NOT_BLOCK)
3243                 return -ECHILD;
3244
3245         res = nfs_revalidate_inode(inode, NFS_INO_INVALID_MODE |
3246                                                   NFS_INO_INVALID_OTHER);
3247         if (res == 0)
3248                 res = generic_permission(&init_user_ns, inode, mask);
3249         goto out;
3250 }
3251 EXPORT_SYMBOL_GPL(nfs_permission);