fs/afs/dir.c

   1 /* dir.c: AFS filesystem directory handling
   2  *
   3  * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/fs.h>
  16 #include <linux/namei.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/ctype.h>
  19 #include <linux/sched.h>
  20 #include "internal.h"
  21
  22 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
  23                                  unsigned int flags);
  24 static int afs_dir_open(struct inode *inode, struct file *file);
  25 static int afs_readdir(struct file *file, struct dir_context *ctx);
  26 static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
  27 static int afs_d_delete(const struct dentry *dentry);
  28 static void afs_d_release(struct dentry *dentry);
  29 static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
  30                                   loff_t fpos, u64 ino, unsigned dtype);
  31 static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  32                       bool excl);
  33 static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
  34 static int afs_rmdir(struct inode *dir, struct dentry *dentry);
  35 static int afs_unlink(struct inode *dir, struct dentry *dentry);
  36 static int afs_link(struct dentry *from, struct inode *dir,
  37                     struct dentry *dentry);
  38 static int afs_symlink(struct inode *dir, struct dentry *dentry,
  39                        const char *content);
  40 static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
  41                       struct inode *new_dir, struct dentry *new_dentry,
  42                       unsigned int flags);
  43
  44 const struct file_operations afs_dir_file_operations = {
  45         .open           = afs_dir_open,
  46         .release        = afs_release,
  47         .iterate_shared = afs_readdir,
  48         .lock           = afs_lock,
  49         .llseek         = generic_file_llseek,
  50 };
  51
  52 const struct inode_operations afs_dir_inode_operations = {
  53         .create         = afs_create,
  54         .lookup         = afs_lookup,
  55         .link           = afs_link,
  56         .unlink         = afs_unlink,
  57         .symlink        = afs_symlink,
  58         .mkdir          = afs_mkdir,
  59         .rmdir          = afs_rmdir,
  60         .rename         = afs_rename,
  61         .permission     = afs_permission,
  62         .getattr        = afs_getattr,
  63         .setattr        = afs_setattr,
  64         .listxattr      = afs_listxattr,
  65 };
  66
  67 const struct dentry_operations afs_fs_dentry_operations = {
  68         .d_revalidate   = afs_d_revalidate,
  69         .d_delete       = afs_d_delete,
  70         .d_release      = afs_d_release,
  71         .d_automount    = afs_d_automount,
  72 };
  73
  74 #define AFS_DIR_HASHTBL_SIZE    128
  75 #define AFS_DIR_DIRENT_SIZE     32
  76 #define AFS_DIRENT_PER_BLOCK    64
  77
  78 union afs_dirent {
  79         struct {
  80                 uint8_t         valid;
  81                 uint8_t         unused[1];
  82                 __be16          hash_next;
  83                 __be32          vnode;
  84                 __be32          unique;
  85                 uint8_t         name[16];
  86                 uint8_t         overflow[4];    /* if any char of the name (inc
  87                                                  * NUL) reaches here, consume
  88                                                  * the next dirent too */
  89         } u;
  90         uint8_t extended_name[32];
  91 };
  92
  93 /* AFS directory page header (one at the beginning of every 2048-byte chunk) */
  94 struct afs_dir_pagehdr {
  95         __be16          npages;
  96         __be16          magic;
  97 #define AFS_DIR_MAGIC htons(1234)
  98         uint8_t         nentries;
  99         uint8_t         bitmap[8];
 100         uint8_t         pad[19];
 101 };
 102
 103 /* directory block layout */
 104 union afs_dir_block {
 105
 106         struct afs_dir_pagehdr pagehdr;
 107
 108         struct {
 109                 struct afs_dir_pagehdr  pagehdr;
 110                 uint8_t                 alloc_ctrs[128];
 111                 /* dir hash table */
 112                 uint16_t                hashtable[AFS_DIR_HASHTBL_SIZE];
 113         } hdr;
 114
 115         union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
 116 };
 117
 118 /* layout on a linux VM page */
 119 struct afs_dir_page {
 120         union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
 121 };
 122
 123 struct afs_lookup_cookie {
 124         struct dir_context ctx;
 125         struct afs_fid  fid;
 126         struct qstr name;
 127         int             found;
 128 };
 129
 130 /*
 131  * check that a directory page is valid
 132  */
 133 bool afs_dir_check_page(struct inode *dir, struct page *page)
 134 {
 135         struct afs_dir_page *dbuf;
 136         struct afs_vnode *vnode = AFS_FS_I(dir);
 137         loff_t latter, i_size, off;
 138         int tmp, qty;
 139
 140 #if 0
 141         /* check the page count */
 142         qty = desc.size / sizeof(dbuf->blocks[0]);
 143         if (qty == 0)
 144                 goto error;
 145
 146         if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
 147                 printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
 148                        __func__, dir->i_ino, qty,
 149                        ntohs(dbuf->blocks[0].pagehdr.npages));
 150                 goto error;
 151         }
 152 #endif
 153
 154         /* Determine how many magic numbers there should be in this page, but
 155          * we must take care because the directory may change size under us.
 156          */
 157         off = page_offset(page);
 158         i_size = i_size_read(dir);
 159         if (i_size <= off)
 160                 goto checked;
 161
 162         latter = i_size - off;
 163         if (latter >= PAGE_SIZE)
 164                 qty = PAGE_SIZE;
 165         else
 166                 qty = latter;
 167         qty /= sizeof(union afs_dir_block);
 168
 169         /* check them */
 170         dbuf = page_address(page);
 171         for (tmp = 0; tmp < qty; tmp++) {
 172                 if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
 173                         printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
 174                                __func__, dir->i_ino, tmp, qty,
 175                                ntohs(dbuf->blocks[tmp].pagehdr.magic));
 176                         trace_afs_dir_check_failed(vnode, off, i_size);
 177                         goto error;
 178                 }
 179         }
 180
 181 checked:
 182         SetPageChecked(page);
 183         return true;
 184
 185 error:
 186         SetPageError(page);
 187         return false;
 188 }
 189
 190 /*
 191  * discard a page cached in the pagecache
 192  */
 193 static inline void afs_dir_put_page(struct page *page)
 194 {
 195         kunmap(page);
 196         unlock_page(page);
 197         put_page(page);
 198 }
 199
 200 /*
 201  * get a page into the pagecache
 202  */
 203 static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
 204                                      struct key *key)
 205 {
 206         struct page *page;
 207         _enter("{%lu},%lu", dir->i_ino, index);
 208
 209         page = read_cache_page(dir->i_mapping, index, afs_page_filler, key);
 210         if (!IS_ERR(page)) {
 211                 lock_page(page);
 212                 kmap(page);
 213                 if (unlikely(!PageChecked(page))) {
 214                         if (PageError(page))
 215                                 goto fail;
 216                 }
 217         }
 218         return page;
 219
 220 fail:
 221         afs_dir_put_page(page);
 222         _leave(" = -EIO");
 223         return ERR_PTR(-EIO);
 224 }
 225
 226 /*
 227  * open an AFS directory file
 228  */
 229 static int afs_dir_open(struct inode *inode, struct file *file)
 230 {
 231         _enter("{%lu}", inode->i_ino);
 232
 233         BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
 234         BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
 235
 236         if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
 237                 return -ENOENT;
 238
 239         return afs_open(inode, file);
 240 }
 241
 242 /*
 243  * deal with one block in an AFS directory
 244  */
 245 static int afs_dir_iterate_block(struct dir_context *ctx,
 246                                  union afs_dir_block *block,
 247                                  unsigned blkoff)
 248 {
 249         union afs_dirent *dire;
 250         unsigned offset, next, curr;
 251         size_t nlen;
 252         int tmp;
 253
 254         _enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
 255
 256         curr = (ctx->pos - blkoff) / sizeof(union afs_dirent);
 257
 258         /* walk through the block, an entry at a time */
 259         for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
 260              offset < AFS_DIRENT_PER_BLOCK;
 261              offset = next
 262              ) {
 263                 next = offset + 1;
 264
 265                 /* skip entries marked unused in the bitmap */
 266                 if (!(block->pagehdr.bitmap[offset / 8] &
 267                       (1 << (offset % 8)))) {
 268                         _debug("ENT[%zu.%u]: unused",
 269                                blkoff / sizeof(union afs_dir_block), offset);
 270                         if (offset >= curr)
 271                                 ctx->pos = blkoff +
 272                                         next * sizeof(union afs_dirent);
 273                         continue;
 274                 }
 275
 276                 /* got a valid entry */
 277                 dire = &block->dirents[offset];
 278                 nlen = strnlen(dire->u.name,
 279                                sizeof(*block) -
 280                                offset * sizeof(union afs_dirent));
 281
 282                 _debug("ENT[%zu.%u]: %s %zu \"%s\"",
 283                        blkoff / sizeof(union afs_dir_block), offset,
 284                        (offset < curr ? "skip" : "fill"),
 285                        nlen, dire->u.name);
 286
 287                 /* work out where the next possible entry is */
 288                 for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {
 289                         if (next >= AFS_DIRENT_PER_BLOCK) {
 290                                 _debug("ENT[%zu.%u]:"
 291                                        " %u travelled beyond end dir block"
 292                                        " (len %u/%zu)",
 293                                        blkoff / sizeof(union afs_dir_block),
 294                                        offset, next, tmp, nlen);
 295                                 return -EIO;
 296                         }
 297                         if (!(block->pagehdr.bitmap[next / 8] &
 298                               (1 << (next % 8)))) {
 299                                 _debug("ENT[%zu.%u]:"
 300                                        " %u unmarked extension (len %u/%zu)",
 301                                        blkoff / sizeof(union afs_dir_block),
 302                                        offset, next, tmp, nlen);
 303                                 return -EIO;
 304                         }
 305
 306                         _debug("ENT[%zu.%u]: ext %u/%zu",
 307                                blkoff / sizeof(union afs_dir_block),
 308                                next, tmp, nlen);
 309                         next++;
 310                 }
 311
 312                 /* skip if starts before the current position */
 313                 if (offset < curr)
 314                         continue;
 315
 316                 /* found the next entry */
 317                 if (!dir_emit(ctx, dire->u.name, nlen,
 318                               ntohl(dire->u.vnode),
 319                               ctx->actor == afs_lookup_filldir ?
 320                               ntohl(dire->u.unique) : DT_UNKNOWN)) {
 321                         _leave(" = 0 [full]");
 322                         return 0;
 323                 }
 324
 325                 ctx->pos = blkoff + next * sizeof(union afs_dirent);
 326         }
 327
 328         _leave(" = 1 [more]");
 329         return 1;
 330 }
 331
 332 /*
 333  * iterate through the data blob that lists the contents of an AFS directory
 334  */
 335 static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 336                            struct key *key)
 337 {
 338         union afs_dir_block *dblock;
 339         struct afs_dir_page *dbuf;
 340         struct page *page;
 341         unsigned blkoff, limit;
 342         int ret;
 343
 344         _enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
 345
 346         if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
 347                 _leave(" = -ESTALE");
 348                 return -ESTALE;
 349         }
 350
 351         /* round the file position up to the next entry boundary */
 352         ctx->pos += sizeof(union afs_dirent) - 1;
 353         ctx->pos &= ~(sizeof(union afs_dirent) - 1);
 354
 355         /* walk through the blocks in sequence */
 356         ret = 0;
 357         while (ctx->pos < dir->i_size) {
 358                 blkoff = ctx->pos & ~(sizeof(union afs_dir_block) - 1);
 359
 360                 /* fetch the appropriate page from the directory */
 361                 page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);
 362                 if (IS_ERR(page)) {
 363                         ret = PTR_ERR(page);
 364                         break;
 365                 }
 366
 367                 limit = blkoff & ~(PAGE_SIZE - 1);
 368
 369                 dbuf = page_address(page);
 370
 371                 /* deal with the individual blocks stashed on this page */
 372                 do {
 373                         dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
 374                                                sizeof(union afs_dir_block)];
 375                         ret = afs_dir_iterate_block(ctx, dblock, blkoff);
 376                         if (ret != 1) {
 377                                 afs_dir_put_page(page);
 378                                 goto out;
 379                         }
 380
 381                         blkoff += sizeof(union afs_dir_block);
 382
 383                 } while (ctx->pos < dir->i_size && blkoff < limit);
 384
 385                 afs_dir_put_page(page);
 386                 ret = 0;
 387         }
 388
 389 out:
 390         _leave(" = %d", ret);
 391         return ret;
 392 }
 393
 394 /*
 395  * read an AFS directory
 396  */
 397 static int afs_readdir(struct file *file, struct dir_context *ctx)
 398 {
 399         return afs_dir_iterate(file_inode(file), ctx, afs_file_key(file));
 400 }
 401
 402 /*
 403  * search the directory for a name
 404  * - if afs_dir_iterate_block() spots this function, it'll pass the FID
 405  *   uniquifier through dtype
 406  */
 407 static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
 408                               int nlen, loff_t fpos, u64 ino, unsigned dtype)
 409 {
 410         struct afs_lookup_cookie *cookie =
 411                 container_of(ctx, struct afs_lookup_cookie, ctx);
 412
 413         _enter("{%s,%u},%s,%u,,%llu,%u",
 414                cookie->name.name, cookie->name.len, name, nlen,
 415                (unsigned long long) ino, dtype);
 416
 417         /* insanity checks first */
 418         BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
 419         BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
 420
 421         if (cookie->name.len != nlen ||
 422             memcmp(cookie->name.name, name, nlen) != 0) {
 423                 _leave(" = 0 [no]");
 424                 return 0;
 425         }
 426
 427         cookie->fid.vnode = ino;
 428         cookie->fid.unique = dtype;
 429         cookie->found = 1;
 430
 431         _leave(" = -1 [found]");
 432         return -1;
 433 }
 434
 435 /*
 436  * do a lookup in a directory
 437  * - just returns the FID the dentry name maps to if found
 438  */
 439 static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
 440                          struct afs_fid *fid, struct key *key)
 441 {
 442         struct afs_super_info *as = dir->i_sb->s_fs_info;
 443         struct afs_lookup_cookie cookie = {
 444                 .ctx.actor = afs_lookup_filldir,
 445                 .name = dentry->d_name,
 446                 .fid.vid = as->volume->vid
 447         };
 448         int ret;
 449
 450         _enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
 451
 452         /* search the directory */
 453         ret = afs_dir_iterate(dir, &cookie.ctx, key);
 454         if (ret < 0) {
 455                 _leave(" = %d [iter]", ret);
 456                 return ret;
 457         }
 458
 459         ret = -ENOENT;
 460         if (!cookie.found) {
 461                 _leave(" = -ENOENT [not found]");
 462                 return -ENOENT;
 463         }
 464
 465         *fid = cookie.fid;
 466         _leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);
 467         return 0;
 468 }
 469
 470 /*
 471  * Try to auto mount the mountpoint with pseudo directory, if the autocell
 472  * operation is setted.
 473  */
 474 static struct inode *afs_try_auto_mntpt(
 475         int ret, struct dentry *dentry, struct inode *dir, struct key *key,
 476         struct afs_fid *fid)
 477 {
 478         const char *devname = dentry->d_name.name;
 479         struct afs_vnode *vnode = AFS_FS_I(dir);
 480         struct inode *inode;
 481
 482         _enter("%d, %p{%pd}, {%x:%u}, %p",
 483                ret, dentry, dentry, vnode->fid.vid, vnode->fid.vnode, key);
 484
 485         if (ret != -ENOENT ||
 486             !test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
 487                 goto out;
 488
 489         inode = afs_iget_autocell(dir, devname, strlen(devname), key);
 490         if (IS_ERR(inode)) {
 491                 ret = PTR_ERR(inode);
 492                 goto out;
 493         }
 494
 495         *fid = AFS_FS_I(inode)->fid;
 496         _leave("= %p", inode);
 497         return inode;
 498
 499 out:
 500         _leave("= %d", ret);
 501         return ERR_PTR(ret);
 502 }
 503
 504 /*
 505  * look up an entry in a directory
 506  */
 507 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 508                                  unsigned int flags)
 509 {
 510         struct afs_vnode *vnode;
 511         struct afs_fid fid;
 512         struct inode *inode;
 513         struct key *key;
 514         int ret;
 515
 516         vnode = AFS_FS_I(dir);
 517
 518         _enter("{%x:%u},%p{%pd},",
 519                vnode->fid.vid, vnode->fid.vnode, dentry, dentry);
 520
 521         ASSERTCMP(d_inode(dentry), ==, NULL);
 522
 523         if (dentry->d_name.len >= AFSNAMEMAX) {
 524                 _leave(" = -ENAMETOOLONG");
 525                 return ERR_PTR(-ENAMETOOLONG);
 526         }
 527
 528         if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 529                 _leave(" = -ESTALE");
 530                 return ERR_PTR(-ESTALE);
 531         }
 532
 533         key = afs_request_key(vnode->volume->cell);
 534         if (IS_ERR(key)) {
 535                 _leave(" = %ld [key]", PTR_ERR(key));
 536                 return ERR_CAST(key);
 537         }
 538
 539         ret = afs_validate(vnode, key);
 540         if (ret < 0) {
 541                 key_put(key);
 542                 _leave(" = %d [val]", ret);
 543                 return ERR_PTR(ret);
 544         }
 545
 546         ret = afs_do_lookup(dir, dentry, &fid, key);
 547         if (ret < 0) {
 548                 inode = afs_try_auto_mntpt(ret, dentry, dir, key, &fid);
 549                 if (!IS_ERR(inode)) {
 550                         key_put(key);
 551                         goto success;
 552                 }
 553
 554                 ret = PTR_ERR(inode);
 555                 key_put(key);
 556                 if (ret == -ENOENT) {
 557                         d_add(dentry, NULL);
 558                         _leave(" = NULL [negative]");
 559                         return NULL;
 560                 }
 561                 _leave(" = %d [do]", ret);
 562                 return ERR_PTR(ret);
 563         }
 564         dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;
 565
 566         /* instantiate the dentry */
 567         inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL, NULL);
 568         key_put(key);
 569         if (IS_ERR(inode)) {
 570                 _leave(" = %ld", PTR_ERR(inode));
 571                 return ERR_CAST(inode);
 572         }
 573
 574 success:
 575         d_add(dentry, inode);
 576         _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
 577                fid.vnode,
 578                fid.unique,
 579                d_inode(dentry)->i_ino,
 580                d_inode(dentry)->i_generation);
 581
 582         return NULL;
 583 }
 584
 585 /*
 586  * check that a dentry lookup hit has found a valid entry
 587  * - NOTE! the hit can be a negative hit too, so we can't assume we have an
 588  *   inode
 589  */
 590 static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
 591 {
 592         struct afs_vnode *vnode, *dir;
 593         struct afs_fid uninitialized_var(fid);
 594         struct dentry *parent;
 595         struct inode *inode;
 596         struct key *key;
 597         void *dir_version;
 598         int ret;
 599
 600         if (flags & LOOKUP_RCU)
 601                 return -ECHILD;
 602
 603         if (d_really_is_positive(dentry)) {
 604                 vnode = AFS_FS_I(d_inode(dentry));
 605                 _enter("{v={%x:%u} n=%pd fl=%lx},",
 606                        vnode->fid.vid, vnode->fid.vnode, dentry,
 607                        vnode->flags);
 608         } else {
 609                 _enter("{neg n=%pd}", dentry);
 610         }
 611
 612         key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
 613         if (IS_ERR(key))
 614                 key = NULL;
 615
 616         if (d_really_is_positive(dentry)) {
 617                 inode = d_inode(dentry);
 618                 if (inode) {
 619                         vnode = AFS_FS_I(inode);
 620                         afs_validate(vnode, key);
 621                         if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 622                                 goto out_bad;
 623                 }
 624         }
 625
 626         /* lock down the parent dentry so we can peer at it */
 627         parent = dget_parent(dentry);
 628         dir = AFS_FS_I(d_inode(parent));
 629
 630         /* validate the parent directory */
 631         afs_validate(dir, key);
 632
 633         if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
 634                 _debug("%pd: parent dir deleted", dentry);
 635                 goto out_bad_parent;
 636         }
 637
 638         dir_version = (void *) (unsigned long) dir->status.data_version;
 639         if (dentry->d_fsdata == dir_version)
 640                 goto out_valid; /* the dir contents are unchanged */
 641
 642         _debug("dir modified");
 643
 644         /* search the directory for this vnode */
 645         ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
 646         switch (ret) {
 647         case 0:
 648                 /* the filename maps to something */
 649                 if (d_really_is_negative(dentry))
 650                         goto out_bad_parent;
 651                 inode = d_inode(dentry);
 652                 if (is_bad_inode(inode)) {
 653                         printk("kAFS: afs_d_revalidate: %pd2 has bad inode\n",
 654                                dentry);
 655                         goto out_bad_parent;
 656                 }
 657
 658                 vnode = AFS_FS_I(inode);
 659
 660                 /* if the vnode ID has changed, then the dirent points to a
 661                  * different file */
 662                 if (fid.vnode != vnode->fid.vnode) {
 663                         _debug("%pd: dirent changed [%u != %u]",
 664                                dentry, fid.vnode,
 665                                vnode->fid.vnode);
 666                         goto not_found;
 667                 }
 668
 669                 /* if the vnode ID uniqifier has changed, then the file has
 670                  * been deleted and replaced, and the original vnode ID has
 671                  * been reused */
 672                 if (fid.unique != vnode->fid.unique) {
 673                         _debug("%pd: file deleted (uq %u -> %u I:%u)",
 674                                dentry, fid.unique,
 675                                vnode->fid.unique,
 676                                vnode->vfs_inode.i_generation);
 677                         write_seqlock(&vnode->cb_lock);
 678                         set_bit(AFS_VNODE_DELETED, &vnode->flags);
 679                         write_sequnlock(&vnode->cb_lock);
 680                         goto not_found;
 681                 }
 682                 goto out_valid;
 683
 684         case -ENOENT:
 685                 /* the filename is unknown */
 686                 _debug("%pd: dirent not found", dentry);
 687                 if (d_really_is_positive(dentry))
 688                         goto not_found;
 689                 goto out_valid;
 690
 691         default:
 692                 _debug("failed to iterate dir %pd: %d",
 693                        parent, ret);
 694                 goto out_bad_parent;
 695         }
 696
 697 out_valid:
 698         dentry->d_fsdata = dir_version;
 699         dput(parent);
 700         key_put(key);
 701         _leave(" = 1 [valid]");
 702         return 1;
 703
 704         /* the dirent, if it exists, now points to a different vnode */
 705 not_found:
 706         spin_lock(&dentry->d_lock);
 707         dentry->d_flags |= DCACHE_NFSFS_RENAMED;
 708         spin_unlock(&dentry->d_lock);
 709
 710 out_bad_parent:
 711         _debug("dropping dentry %pd2", dentry);
 712         dput(parent);
 713 out_bad:
 714         key_put(key);
 715
 716         _leave(" = 0 [bad]");
 717         return 0;
 718 }
 719
 720 /*
 721  * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
 722  * sleep)
 723  * - called from dput() when d_count is going to 0.
 724  * - return 1 to request dentry be unhashed, 0 otherwise
 725  */
 726 static int afs_d_delete(const struct dentry *dentry)
 727 {
 728         _enter("%pd", dentry);
 729
 730         if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
 731                 goto zap;
 732
 733         if (d_really_is_positive(dentry) &&
 734             (test_bit(AFS_VNODE_DELETED,   &AFS_FS_I(d_inode(dentry))->flags) ||
 735              test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(d_inode(dentry))->flags)))
 736                 goto zap;
 737
 738         _leave(" = 0 [keep]");
 739         return 0;
 740
 741 zap:
 742         _leave(" = 1 [zap]");
 743         return 1;
 744 }
 745
 746 /*
 747  * handle dentry release
 748  */
 749 static void afs_d_release(struct dentry *dentry)
 750 {
 751         _enter("%pd", dentry);
 752 }
 753
 754 /*
 755  * Create a new inode for create/mkdir/symlink
 756  */
 757 static void afs_vnode_new_inode(struct afs_fs_cursor *fc,
 758                                 struct dentry *new_dentry,
 759                                 struct afs_fid *newfid,
 760                                 struct afs_file_status *newstatus,
 761                                 struct afs_callback *newcb)
 762 {
 763         struct inode *inode;
 764
 765         if (fc->ac.error < 0)
 766                 return;
 767
 768         d_drop(new_dentry);
 769
 770         inode = afs_iget(fc->vnode->vfs_inode.i_sb, fc->key,
 771                          newfid, newstatus, newcb, fc->cbi);
 772         if (IS_ERR(inode)) {
 773                 /* ENOMEM or EINTR at a really inconvenient time - just abandon
 774                  * the new directory on the server.
 775                  */
 776                 fc->ac.error = PTR_ERR(inode);
 777                 return;
 778         }
 779
 780         d_add(new_dentry, inode);
 781 }
 782
 783 /*
 784  * create a directory on an AFS filesystem
 785  */
 786 static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 787 {
 788         struct afs_file_status newstatus;
 789         struct afs_fs_cursor fc;
 790         struct afs_callback newcb;
 791         struct afs_vnode *dvnode = AFS_FS_I(dir);
 792         struct afs_fid newfid;
 793         struct key *key;
 794         int ret;
 795
 796         mode |= S_IFDIR;
 797
 798         _enter("{%x:%u},{%pd},%ho",
 799                dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
 800
 801         key = afs_request_key(dvnode->volume->cell);
 802         if (IS_ERR(key)) {
 803                 ret = PTR_ERR(key);
 804                 goto error;
 805         }
 806
 807         ret = -ERESTARTSYS;
 808         if (afs_begin_vnode_operation(&fc, dvnode, key)) {
 809                 while (afs_select_fileserver(&fc)) {
 810                         fc.cb_break = dvnode->cb_break + dvnode->cb_s_break;
 811                         afs_fs_create(&fc, dentry->d_name.name, mode,
 812                                       &newfid, &newstatus, &newcb);
 813                 }
 814
 815                 afs_check_for_remote_deletion(&fc, fc.vnode);
 816                 afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
 817                 afs_vnode_new_inode(&fc, dentry, &newfid, &newstatus, &newcb);
 818                 ret = afs_end_vnode_operation(&fc);
 819                 if (ret < 0)
 820                         goto error_key;
 821         } else {
 822                 goto error_key;
 823         }
 824
 825         key_put(key);
 826         _leave(" = 0");
 827         return 0;
 828
 829 error_key:
 830         key_put(key);
 831 error:
 832         d_drop(dentry);
 833         _leave(" = %d", ret);
 834         return ret;
 835 }
 836
 837 /*
 838  * Remove a subdir from a directory.
 839  */
 840 static void afs_dir_remove_subdir(struct dentry *dentry)
 841 {
 842         if (d_really_is_positive(dentry)) {
 843                 struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
 844
 845                 clear_nlink(&vnode->vfs_inode);
 846                 set_bit(AFS_VNODE_DELETED, &vnode->flags);
 847                 clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
 848         }
 849 }
 850
 851 /*
 852  * remove a directory from an AFS filesystem
 853  */
 854 static int afs_rmdir(struct inode *dir, struct dentry *dentry)
 855 {
 856         struct afs_fs_cursor fc;
 857         struct afs_vnode *dvnode = AFS_FS_I(dir);
 858         struct key *key;
 859         int ret;
 860
 861         _enter("{%x:%u},{%pd}",
 862                dvnode->fid.vid, dvnode->fid.vnode, dentry);
 863
 864         key = afs_request_key(dvnode->volume->cell);
 865         if (IS_ERR(key)) {
 866                 ret = PTR_ERR(key);
 867                 goto error;
 868         }
 869
 870         ret = -ERESTARTSYS;
 871         if (afs_begin_vnode_operation(&fc, dvnode, key)) {
 872                 while (afs_select_fileserver(&fc)) {
 873                         fc.cb_break = dvnode->cb_break + dvnode->cb_s_break;
 874                         afs_fs_remove(&fc, dentry->d_name.name, true);
 875                 }
 876
 877                 afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
 878                 ret = afs_end_vnode_operation(&fc);
 879                 if (ret == 0)
 880                         afs_dir_remove_subdir(dentry);
 881         }
 882
 883         key_put(key);
 884 error:
 885         return ret;
 886 }
 887
 888 /*
 889  * Remove a link to a file or symlink from a directory.
 890  *
 891  * If the file was not deleted due to excess hard links, the fileserver will
 892  * break the callback promise on the file - if it had one - before it returns
 893  * to us, and if it was deleted, it won't
 894  *
 895  * However, if we didn't have a callback promise outstanding, or it was
 896  * outstanding on a different server, then it won't break it either...
 897  */
 898 static int afs_dir_remove_link(struct dentry *dentry, struct key *key,
 899                                unsigned long d_version_before,
 900                                unsigned long d_version_after)
 901 {
 902         bool dir_valid;
 903         int ret = 0;
 904
 905         /* There were no intervening changes on the server if the version
 906          * number we got back was incremented by exactly 1.
 907          */
 908         dir_valid = (d_version_after == d_version_before + 1);
 909
 910         if (d_really_is_positive(dentry)) {
 911                 struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
 912
 913                 if (dir_valid) {
 914                         drop_nlink(&vnode->vfs_inode);
 915                         if (vnode->vfs_inode.i_nlink == 0) {
 916                                 set_bit(AFS_VNODE_DELETED, &vnode->flags);
 917                                 clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
 918                         }
 919                         ret = 0;
 920                 } else {
 921                         clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
 922
 923                         if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 924                                 kdebug("AFS_VNODE_DELETED");
 925
 926                         ret = afs_validate(vnode, key);
 927                         if (ret == -ESTALE)
 928                                 ret = 0;
 929                 }
 930                 _debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
 931         }
 932
 933         return ret;
 934 }
 935
 936 /*
 937  * Remove a file or symlink from an AFS filesystem.
 938  */
 939 static int afs_unlink(struct inode *dir, struct dentry *dentry)
 940 {
 941         struct afs_fs_cursor fc;
 942         struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode;
 943         struct key *key;
 944         unsigned long d_version = (unsigned long)dentry->d_fsdata;
 945         int ret;
 946
 947         _enter("{%x:%u},{%pd}",
 948                dvnode->fid.vid, dvnode->fid.vnode, dentry);
 949
 950         if (dentry->d_name.len >= AFSNAMEMAX)
 951                 return -ENAMETOOLONG;
 952
 953         key = afs_request_key(dvnode->volume->cell);
 954         if (IS_ERR(key)) {
 955                 ret = PTR_ERR(key);
 956                 goto error;
 957         }
 958
 959         /* Try to make sure we have a callback promise on the victim. */
 960         if (d_really_is_positive(dentry)) {
 961                 vnode = AFS_FS_I(d_inode(dentry));
 962                 ret = afs_validate(vnode, key);
 963                 if (ret < 0)
 964                         goto error_key;
 965         }
 966
 967         ret = -ERESTARTSYS;
 968         if (afs_begin_vnode_operation(&fc, dvnode, key)) {
 969                 while (afs_select_fileserver(&fc)) {
 970                         fc.cb_break = dvnode->cb_break + dvnode->cb_s_break;
 971                         afs_fs_remove(&fc, dentry->d_name.name, false);
 972                 }
 973
 974                 afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
 975                 ret = afs_end_vnode_operation(&fc);
 976                 if (ret == 0)
 977                         ret = afs_dir_remove_link(
 978                                 dentry, key, d_version,
 979                                 (unsigned long)dvnode->status.data_version);
 980         }
 981
 982 error_key:
 983         key_put(key);
 984 error:
 985         _leave(" = %d", ret);
 986         return ret;
 987 }
 988
 989 /*
 990  * create a regular file on an AFS filesystem
 991  */
 992 static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 993                       bool excl)
 994 {
 995         struct afs_fs_cursor fc;
 996         struct afs_file_status newstatus;
 997         struct afs_callback newcb;
 998         struct afs_vnode *dvnode = AFS_FS_I(dir);
 999         struct afs_fid newfid;
1000         struct key *key;
1001         int ret;
1002
1003         mode |= S_IFREG;
1004
1005         _enter("{%x:%u},{%pd},%ho,",
1006                dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
1007
1008         ret = -ENAMETOOLONG;
1009         if (dentry->d_name.len >= AFSNAMEMAX)
1010                 goto error;
1011
1012         key = afs_request_key(dvnode->volume->cell);
1013         if (IS_ERR(key)) {
1014                 ret = PTR_ERR(key);
1015                 goto error;
1016         }
1017
1018         ret = -ERESTARTSYS;
1019         if (afs_begin_vnode_operation(&fc, dvnode, key)) {
1020                 while (afs_select_fileserver(&fc)) {
1021                         fc.cb_break = dvnode->cb_break + dvnode->cb_s_break;
1022                         afs_fs_create(&fc, dentry->d_name.name, mode,
1023                                       &newfid, &newstatus, &newcb);
1024                 }
1025
1026                 afs_check_for_remote_deletion(&fc, fc.vnode);
1027                 afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
1028                 afs_vnode_new_inode(&fc, dentry, &newfid, &newstatus, &newcb);
1029                 ret = afs_end_vnode_operation(&fc);
1030                 if (ret < 0)
1031                         goto error_key;
1032         } else {
1033                 goto error_key;
1034         }
1035
1036         key_put(key);
1037         _leave(" = 0");
1038         return 0;
1039
1040 error_key:
1041         key_put(key);
1042 error:
1043         d_drop(dentry);
1044         _leave(" = %d", ret);
1045         return ret;
1046 }
1047
1048 /*
1049  * create a hard link between files in an AFS filesystem
1050  */
1051 static int afs_link(struct dentry *from, struct inode *dir,
1052                     struct dentry *dentry)
1053 {
1054         struct afs_fs_cursor fc;
1055         struct afs_vnode *dvnode, *vnode;
1056         struct key *key;
1057         int ret;
1058
1059         vnode = AFS_FS_I(d_inode(from));
1060         dvnode = AFS_FS_I(dir);
1061
1062         _enter("{%x:%u},{%x:%u},{%pd}",
1063                vnode->fid.vid, vnode->fid.vnode,
1064                dvnode->fid.vid, dvnode->fid.vnode,
1065                dentry);
1066
1067         ret = -ENAMETOOLONG;
1068         if (dentry->d_name.len >= AFSNAMEMAX)
1069                 goto error;
1070
1071         key = afs_request_key(dvnode->volume->cell);
1072         if (IS_ERR(key)) {
1073                 ret = PTR_ERR(key);
1074                 goto error;
1075         }
1076
1077         ret = -ERESTARTSYS;
1078         if (afs_begin_vnode_operation(&fc, dvnode, key)) {
1079                 if (mutex_lock_interruptible_nested(&vnode->io_lock, 1) < 0) {
1080                         afs_end_vnode_operation(&fc);
1081                         goto error_key;
1082                 }
1083
1084                 while (afs_select_fileserver(&fc)) {
1085                         fc.cb_break = dvnode->cb_break + dvnode->cb_s_break;
1086                         fc.cb_break_2 = vnode->cb_break + vnode->cb_s_break;
1087                         afs_fs_link(&fc, vnode, dentry->d_name.name);
1088                 }
1089
1090                 afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
1091                 afs_vnode_commit_status(&fc, vnode, fc.cb_break_2);
1092                 ihold(&vnode->vfs_inode);
1093                 d_instantiate(dentry, &vnode->vfs_inode);
1094
1095                 mutex_unlock(&vnode->io_lock);
1096                 ret = afs_end_vnode_operation(&fc);
1097                 if (ret < 0)
1098                         goto error_key;
1099         } else {
1100                 goto error_key;
1101         }
1102
1103         key_put(key);
1104         _leave(" = 0");
1105         return 0;
1106
1107 error_key:
1108         key_put(key);
1109 error:
1110         d_drop(dentry);
1111         _leave(" = %d", ret);
1112         return ret;
1113 }
1114
1115 /*
1116  * create a symlink in an AFS filesystem
1117  */
1118 static int afs_symlink(struct inode *dir, struct dentry *dentry,
1119                        const char *content)
1120 {
1121         struct afs_fs_cursor fc;
1122         struct afs_file_status newstatus;
1123         struct afs_vnode *dvnode = AFS_FS_I(dir);
1124         struct afs_fid newfid;
1125         struct key *key;
1126         int ret;
1127
1128         _enter("{%x:%u},{%pd},%s",
1129                dvnode->fid.vid, dvnode->fid.vnode, dentry,
1130                content);
1131
1132         ret = -ENAMETOOLONG;
1133         if (dentry->d_name.len >= AFSNAMEMAX)
1134                 goto error;
1135
1136         ret = -EINVAL;
1137         if (strlen(content) >= AFSPATHMAX)
1138                 goto error;
1139
1140         key = afs_request_key(dvnode->volume->cell);
1141         if (IS_ERR(key)) {
1142                 ret = PTR_ERR(key);
1143                 goto error;
1144         }
1145
1146         ret = -ERESTARTSYS;
1147         if (afs_begin_vnode_operation(&fc, dvnode, key)) {
1148                 while (afs_select_fileserver(&fc)) {
1149                         fc.cb_break = dvnode->cb_break + dvnode->cb_s_break;
1150                         afs_fs_symlink(&fc, dentry->d_name.name, content,
1151                                        &newfid, &newstatus);
1152                 }
1153
1154                 afs_check_for_remote_deletion(&fc, fc.vnode);
1155                 afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
1156                 afs_vnode_new_inode(&fc, dentry, &newfid, &newstatus, NULL);
1157                 ret = afs_end_vnode_operation(&fc);
1158                 if (ret < 0)
1159                         goto error_key;
1160         } else {
1161                 goto error_key;
1162         }
1163
1164         key_put(key);
1165         _leave(" = 0");
1166         return 0;
1167
1168 error_key:
1169         key_put(key);
1170 error:
1171         d_drop(dentry);
1172         _leave(" = %d", ret);
1173         return ret;
1174 }
1175
1176 /*
1177  * rename a file in an AFS filesystem and/or move it between directories
1178  */
1179 static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
1180                       struct inode *new_dir, struct dentry *new_dentry,
1181                       unsigned int flags)
1182 {
1183         struct afs_fs_cursor fc;
1184         struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
1185         struct key *key;
1186         int ret;
1187
1188         if (flags)
1189                 return -EINVAL;
1190
1191         vnode = AFS_FS_I(d_inode(old_dentry));
1192         orig_dvnode = AFS_FS_I(old_dir);
1193         new_dvnode = AFS_FS_I(new_dir);
1194
1195         _enter("{%x:%u},{%x:%u},{%x:%u},{%pd}",
1196                orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
1197                vnode->fid.vid, vnode->fid.vnode,
1198                new_dvnode->fid.vid, new_dvnode->fid.vnode,
1199                new_dentry);
1200
1201         key = afs_request_key(orig_dvnode->volume->cell);
1202         if (IS_ERR(key)) {
1203                 ret = PTR_ERR(key);
1204                 goto error;
1205         }
1206
1207         ret = -ERESTARTSYS;
1208         if (afs_begin_vnode_operation(&fc, orig_dvnode, key)) {
1209                 if (orig_dvnode != new_dvnode) {
1210                         if (mutex_lock_interruptible_nested(&new_dvnode->io_lock, 1) < 0) {
1211                                 afs_end_vnode_operation(&fc);
1212                                 goto error_key;
1213                         }
1214                 }
1215                 while (afs_select_fileserver(&fc)) {
1216                         fc.cb_break = orig_dvnode->cb_break + orig_dvnode->cb_s_break;
1217                         fc.cb_break_2 = new_dvnode->cb_break + new_dvnode->cb_s_break;
1218                         afs_fs_rename(&fc, old_dentry->d_name.name,
1219                                       new_dvnode, new_dentry->d_name.name);
1220                 }
1221
1222                 afs_vnode_commit_status(&fc, orig_dvnode, fc.cb_break);
1223                 afs_vnode_commit_status(&fc, new_dvnode, fc.cb_break_2);
1224                 if (orig_dvnode != new_dvnode)
1225                         mutex_unlock(&new_dvnode->io_lock);
1226                 ret = afs_end_vnode_operation(&fc);
1227                 if (ret < 0)
1228                         goto error_key;
1229         }
1230
1231 error_key:
1232         key_put(key);
1233 error:
1234         _leave(" = %d", ret);
1235         return ret;
1236 }