fs/autofs4/root.c

   1 /* -*- c -*- --------------------------------------------------------------- *
   2  *
   3  * linux/fs/autofs/root.c
   4  *
   5  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   6  *  Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
   7  *  Copyright 2001-2003 Ian Kent <raven@themaw.net>
   8  *
   9  * This file is part of the Linux kernel and is made available under
  10  * the terms of the GNU General Public License, version 2, or at your
  11  * option, any later version, incorporated herein by reference.
  12  *
  13  * ------------------------------------------------------------------------- */
  14
  15 #include <linux/errno.h>
  16 #include <linux/stat.h>
  17 #include <linux/param.h>
  18 #include <linux/time.h>
  19 #include <linux/smp_lock.h>
  20 #include "autofs_i.h"
  21
  22 static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
  23 static int autofs4_dir_unlink(struct inode *,struct dentry *);
  24 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
  25 static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
  26 static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
  27 static int autofs4_dir_open(struct inode *inode, struct file *file);
  28 static int autofs4_dir_close(struct inode *inode, struct file *file);
  29 static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
  30 static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
  31 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
  32 static int autofs4_dcache_readdir(struct file *, void *, filldir_t);
  33
  34 struct file_operations autofs4_root_operations = {
  35         .open           = dcache_dir_open,
  36         .release        = dcache_dir_close,
  37         .read           = generic_read_dir,
  38         .readdir        = autofs4_root_readdir,
  39         .ioctl          = autofs4_root_ioctl,
  40 };
  41
  42 struct file_operations autofs4_dir_operations = {
  43         .open           = autofs4_dir_open,
  44         .release        = autofs4_dir_close,
  45         .read           = generic_read_dir,
  46         .readdir        = autofs4_dir_readdir,
  47 };
  48
  49 struct inode_operations autofs4_root_inode_operations = {
  50         .lookup         = autofs4_lookup,
  51         .unlink         = autofs4_dir_unlink,
  52         .symlink        = autofs4_dir_symlink,
  53         .mkdir          = autofs4_dir_mkdir,
  54         .rmdir          = autofs4_dir_rmdir,
  55 };
  56
  57 struct inode_operations autofs4_dir_inode_operations = {
  58         .lookup         = autofs4_lookup,
  59         .unlink         = autofs4_dir_unlink,
  60         .symlink        = autofs4_dir_symlink,
  61         .mkdir          = autofs4_dir_mkdir,
  62         .rmdir          = autofs4_dir_rmdir,
  63 };
  64
  65 static int autofs4_root_readdir(struct file *file, void *dirent,
  66                                 filldir_t filldir)
  67 {
  68         struct autofs_sb_info *sbi = autofs4_sbi(file->f_dentry->d_sb);
  69         int oz_mode = autofs4_oz_mode(sbi);
  70
  71         DPRINTK("called, filp->f_pos = %lld", file->f_pos);
  72
  73         /*
  74          * Don't set reghost flag if:
  75          * 1) f_pos is larger than zero -- we've already been here.
  76          * 2) we haven't even enabled reghosting in the 1st place.
  77          * 3) this is the daemon doing a readdir
  78          */
  79         if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled)
  80                 sbi->needs_reghost = 1;
  81
  82         DPRINTK("needs_reghost = %d", sbi->needs_reghost);
  83
  84         return autofs4_dcache_readdir(file, dirent, filldir);
  85 }
  86
  87 /* Update usage from here to top of tree, so that scan of
  88    top-level directories will give a useful result */
  89 static void autofs4_update_usage(struct dentry *dentry)
  90 {
  91         struct dentry *top = dentry->d_sb->s_root;
  92
  93         spin_lock(&dcache_lock);
  94         for(; dentry != top; dentry = dentry->d_parent) {
  95                 struct autofs_info *ino = autofs4_dentry_ino(dentry);
  96
  97                 if (ino) {
  98                         update_atime(dentry->d_inode);
  99                         ino->last_used = jiffies;
 100                 }
 101         }
 102         spin_unlock(&dcache_lock);
 103 }
 104
 105 /*
 106  * From 2.4 kernel readdir.c
 107  */
 108 static int autofs4_dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
 109 {
 110         int i;
 111         struct dentry *dentry = filp->f_dentry;
 112
 113         i = filp->f_pos;
 114         switch (i) {
 115                 case 0:
 116                         if (filldir(dirent, ".", 1, i, dentry->d_inode->i_ino, DT_DIR) < 0)
 117                                 break;
 118                         i++;
 119                         filp->f_pos++;
 120                         /* fallthrough */
 121                 case 1:
 122                         if (filldir(dirent, "..", 2, i, dentry->d_parent->d_inode->i_ino, DT_DIR) < 0)
 123                                 break;
 124                         i++;
 125                         filp->f_pos++;
 126                         /* fallthrough */
 127                 default: {
 128                         struct list_head *list;
 129                         int j = i-2;
 130
 131                         spin_lock(&dcache_lock);
 132                         list = dentry->d_subdirs.next;
 133
 134                         for (;;) {
 135                                 if (list == &dentry->d_subdirs) {
 136                                         spin_unlock(&dcache_lock);
 137                                         return 0;
 138                                 }
 139                                 if (!j)
 140                                         break;
 141                                 j--;
 142                                 list = list->next;
 143                         }
 144
 145                         while(1) {
 146                                 struct dentry *de = list_entry(list,
 147                                                 struct dentry, d_u.d_child);
 148
 149                                 if (!d_unhashed(de) && de->d_inode) {
 150                                         spin_unlock(&dcache_lock);
 151                                         if (filldir(dirent, de->d_name.name, de->d_name.len, filp->f_pos, de->d_inode->i_ino, DT_UNKNOWN) < 0)
 152                                                 break;
 153                                         spin_lock(&dcache_lock);
 154                                 }
 155                                 filp->f_pos++;
 156                                 list = list->next;
 157                                 if (list != &dentry->d_subdirs)
 158                                         continue;
 159                                 spin_unlock(&dcache_lock);
 160                                 break;
 161                         }
 162                 }
 163         }
 164         return 0;
 165 }
 166
 167 static int autofs4_dir_open(struct inode *inode, struct file *file)
 168 {
 169         struct dentry *dentry = file->f_dentry;
 170         struct vfsmount *mnt = file->f_vfsmnt;
 171         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 172         int status;
 173
 174         DPRINTK("file=%p dentry=%p %.*s",
 175                 file, dentry, dentry->d_name.len, dentry->d_name.name);
 176
 177         if (autofs4_oz_mode(sbi))
 178                 goto out;
 179
 180         if (autofs4_ispending(dentry)) {
 181                 DPRINTK("dentry busy");
 182                 return -EBUSY;
 183         }
 184
 185         if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
 186                 struct nameidata nd;
 187                 int empty;
 188
 189                 /* In case there are stale directory dentrys from a failed mount */
 190                 spin_lock(&dcache_lock);
 191                 empty = list_empty(&dentry->d_subdirs);
 192                 spin_unlock(&dcache_lock);
 193
 194                 if (!empty)
 195                         d_invalidate(dentry);
 196
 197                 nd.flags = LOOKUP_DIRECTORY;
 198                 status = (dentry->d_op->d_revalidate)(dentry, &nd);
 199
 200                 if (!status)
 201                         return -ENOENT;
 202         }
 203
 204         if (d_mountpoint(dentry)) {
 205                 struct file *fp = NULL;
 206                 struct vfsmount *fp_mnt = mntget(mnt);
 207                 struct dentry *fp_dentry = dget(dentry);
 208
 209                 if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {
 210                         dput(fp_dentry);
 211                         mntput(fp_mnt);
 212                         return -ENOENT;
 213                 }
 214
 215                 fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
 216                 status = PTR_ERR(fp);
 217                 if (IS_ERR(fp)) {
 218                         file->private_data = NULL;
 219                         return status;
 220                 }
 221                 file->private_data = fp;
 222         }
 223 out:
 224         return 0;
 225 }
 226
 227 static int autofs4_dir_close(struct inode *inode, struct file *file)
 228 {
 229         struct dentry *dentry = file->f_dentry;
 230         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 231
 232         DPRINTK("file=%p dentry=%p %.*s",
 233                 file, dentry, dentry->d_name.len, dentry->d_name.name);
 234
 235         if (autofs4_oz_mode(sbi))
 236                 goto out;
 237
 238         if (autofs4_ispending(dentry)) {
 239                 DPRINTK("dentry busy");
 240                 return -EBUSY;
 241         }
 242
 243         if (d_mountpoint(dentry)) {
 244                 struct file *fp = file->private_data;
 245
 246                 if (!fp)
 247                         return -ENOENT;
 248
 249                 filp_close(fp, current->files);
 250                 file->private_data = NULL;
 251         }
 252 out:
 253         return 0;
 254 }
 255
 256 static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
 257 {
 258         struct dentry *dentry = file->f_dentry;
 259         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 260         int status;
 261
 262         DPRINTK("file=%p dentry=%p %.*s",
 263                 file, dentry, dentry->d_name.len, dentry->d_name.name);
 264
 265         if (autofs4_oz_mode(sbi))
 266                 goto out;
 267
 268         if (autofs4_ispending(dentry)) {
 269                 DPRINTK("dentry busy");
 270                 return -EBUSY;
 271         }
 272
 273         if (d_mountpoint(dentry)) {
 274                 struct file *fp = file->private_data;
 275
 276                 if (!fp)
 277                         return -ENOENT;
 278
 279                 if (!fp->f_op || !fp->f_op->readdir)
 280                         goto out;
 281
 282                 status = vfs_readdir(fp, filldir, dirent);
 283                 file->f_pos = fp->f_pos;
 284                 if (status)
 285                         autofs4_copy_atime(file, fp);
 286                 return status;
 287         }
 288 out:
 289         return autofs4_dcache_readdir(file, dirent, filldir);
 290 }
 291
 292 static int try_to_fill_dentry(struct dentry *dentry,
 293                               struct super_block *sb,
 294                               struct autofs_sb_info *sbi, int flags)
 295 {
 296         struct autofs_info *de_info = autofs4_dentry_ino(dentry);
 297         int status = 0;
 298
 299         /* Block on any pending expiry here; invalidate the dentry
 300            when expiration is done to trigger mount request with a new
 301            dentry */
 302         if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) {
 303                 DPRINTK("waiting for expire %p name=%.*s",
 304                          dentry, dentry->d_name.len, dentry->d_name.name);
 305
 306                 status = autofs4_wait(sbi, dentry, NFY_NONE);
 307
 308                 DPRINTK("expire done status=%d", status);
 309
 310                 /*
 311                  * If the directory still exists the mount request must
 312                  * continue otherwise it can't be followed at the right
 313                  * time during the walk.
 314                  */
 315                 status = d_invalidate(dentry);
 316                 if (status != -EBUSY)
 317                         return 0;
 318         }
 319
 320         DPRINTK("dentry=%p %.*s ino=%p",
 321                  dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
 322
 323         /* Wait for a pending mount, triggering one if there isn't one already */
 324         if (dentry->d_inode == NULL) {
 325                 DPRINTK("waiting for mount name=%.*s",
 326                          dentry->d_name.len, dentry->d_name.name);
 327
 328                 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
 329
 330                 DPRINTK("mount done status=%d", status);
 331
 332                 if (status && dentry->d_inode)
 333                         return 0; /* Try to get the kernel to invalidate this dentry */
 334
 335                 /* Turn this into a real negative dentry? */
 336                 if (status == -ENOENT) {
 337                         dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
 338                         spin_lock(&dentry->d_lock);
 339                         dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 340                         spin_unlock(&dentry->d_lock);
 341                         return 1;
 342                 } else if (status) {
 343                         /* Return a negative dentry, but leave it "pending" */
 344                         return 1;
 345                 }
 346         /* Trigger mount for path component or follow link */
 347         } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
 348                         current->link_count) {
 349                 DPRINTK("waiting for mount name=%.*s",
 350                         dentry->d_name.len, dentry->d_name.name);
 351
 352                 spin_lock(&dentry->d_lock);
 353                 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
 354                 spin_unlock(&dentry->d_lock);
 355                 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
 356
 357                 DPRINTK("mount done status=%d", status);
 358
 359                 if (status) {
 360                         spin_lock(&dentry->d_lock);
 361                         dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 362                         spin_unlock(&dentry->d_lock);
 363                         return 0;
 364                 }
 365         }
 366
 367         /* We don't update the usages for the autofs daemon itself, this
 368            is necessary for recursive autofs mounts */
 369         if (!autofs4_oz_mode(sbi))
 370                 autofs4_update_usage(dentry);
 371
 372         spin_lock(&dentry->d_lock);
 373         dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 374         spin_unlock(&dentry->d_lock);
 375         return 1;
 376 }
 377
 378 /*
 379  * Revalidate is called on every cache lookup.  Some of those
 380  * cache lookups may actually happen while the dentry is not
 381  * yet completely filled in, and revalidate has to delay such
 382  * lookups..
 383  */
 384 static int autofs4_revalidate(struct dentry * dentry, struct nameidata *nd)
 385 {
 386         struct inode * dir = dentry->d_parent->d_inode;
 387         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 388         int oz_mode = autofs4_oz_mode(sbi);
 389         int flags = nd ? nd->flags : 0;
 390         int status = 1;
 391
 392         /* Pending dentry */
 393         if (autofs4_ispending(dentry)) {
 394                 if (!oz_mode)
 395                         status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags);
 396                 return status;
 397         }
 398
 399         /* Negative dentry.. invalidate if "old" */
 400         if (dentry->d_inode == NULL)
 401                 return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
 402
 403         /* Check for a non-mountpoint directory with no contents */
 404         spin_lock(&dcache_lock);
 405         if (S_ISDIR(dentry->d_inode->i_mode) &&
 406             !d_mountpoint(dentry) &&
 407             list_empty(&dentry->d_subdirs)) {
 408                 DPRINTK("dentry=%p %.*s, emptydir",
 409                          dentry, dentry->d_name.len, dentry->d_name.name);
 410                 spin_unlock(&dcache_lock);
 411                 if (!oz_mode)
 412                         status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags);
 413                 return status;
 414         }
 415         spin_unlock(&dcache_lock);
 416
 417         /* Update the usage list */
 418         if (!oz_mode)
 419                 autofs4_update_usage(dentry);
 420
 421         return 1;
 422 }
 423
 424 static void autofs4_dentry_release(struct dentry *de)
 425 {
 426         struct autofs_info *inf;
 427
 428         DPRINTK("releasing %p", de);
 429
 430         inf = autofs4_dentry_ino(de);
 431         de->d_fsdata = NULL;
 432
 433         if (inf) {
 434                 inf->dentry = NULL;
 435                 inf->inode = NULL;
 436
 437                 autofs4_free_ino(inf);
 438         }
 439 }
 440
 441 /* For dentries of directories in the root dir */
 442 static struct dentry_operations autofs4_root_dentry_operations = {
 443         .d_revalidate   = autofs4_revalidate,
 444         .d_release      = autofs4_dentry_release,
 445 };
 446
 447 /* For other dentries */
 448 static struct dentry_operations autofs4_dentry_operations = {
 449         .d_revalidate   = autofs4_revalidate,
 450         .d_release      = autofs4_dentry_release,
 451 };
 452
 453 /* Lookups in the root directory */
 454 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 455 {
 456         struct autofs_sb_info *sbi;
 457         int oz_mode;
 458
 459         DPRINTK("name = %.*s",
 460                 dentry->d_name.len, dentry->d_name.name);
 461
 462         if (dentry->d_name.len > NAME_MAX)
 463                 return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
 464
 465         sbi = autofs4_sbi(dir->i_sb);
 466
 467         oz_mode = autofs4_oz_mode(sbi);
 468         DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
 469                  current->pid, process_group(current), sbi->catatonic, oz_mode);
 470
 471         /*
 472          * Mark the dentry incomplete, but add it. This is needed so
 473          * that the VFS layer knows about the dentry, and we can count
 474          * on catching any lookups through the revalidate.
 475          *
 476          * Let all the hard work be done by the revalidate function that
 477          * needs to be able to do this anyway..
 478          *
 479          * We need to do this before we release the directory semaphore.
 480          */
 481         dentry->d_op = &autofs4_root_dentry_operations;
 482
 483         if (!oz_mode) {
 484                 spin_lock(&dentry->d_lock);
 485                 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
 486                 spin_unlock(&dentry->d_lock);
 487         }
 488         dentry->d_fsdata = NULL;
 489         d_add(dentry, NULL);
 490
 491         if (dentry->d_op && dentry->d_op->d_revalidate) {
 492                 up(&dir->i_sem);
 493                 (dentry->d_op->d_revalidate)(dentry, nd);
 494                 down(&dir->i_sem);
 495         }
 496
 497         /*
 498          * If we are still pending, check if we had to handle
 499          * a signal. If so we can force a restart..
 500          */
 501         if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
 502                 /* See if we were interrupted */
 503                 if (signal_pending(current)) {
 504                         sigset_t *sigset = &current->pending.signal;
 505                         if (sigismember (sigset, SIGKILL) ||
 506                             sigismember (sigset, SIGQUIT) ||
 507                             sigismember (sigset, SIGINT)) {
 508                             return ERR_PTR(-ERESTARTNOINTR);
 509                         }
 510                 }
 511         }
 512
 513         /*
 514          * If this dentry is unhashed, then we shouldn't honour this
 515          * lookup even if the dentry is positive.  Returning ENOENT here
 516          * doesn't do the right thing for all system calls, but it should
 517          * be OK for the operations we permit from an autofs.
 518          */
 519         if ( dentry->d_inode && d_unhashed(dentry) )
 520                 return ERR_PTR(-ENOENT);
 521
 522         return NULL;
 523 }
 524
 525 static int autofs4_dir_symlink(struct inode *dir,
 526                                struct dentry *dentry,
 527                                const char *symname)
 528 {
 529         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 530         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 531         struct inode *inode;
 532         char *cp;
 533
 534         DPRINTK("%s <- %.*s", symname,
 535                 dentry->d_name.len, dentry->d_name.name);
 536
 537         if (!autofs4_oz_mode(sbi))
 538                 return -EACCES;
 539
 540         ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
 541         if (ino == NULL)
 542                 return -ENOSPC;
 543
 544         ino->size = strlen(symname);
 545         ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
 546
 547         if (cp == NULL) {
 548                 kfree(ino);
 549                 return -ENOSPC;
 550         }
 551
 552         strcpy(cp, symname);
 553
 554         inode = autofs4_get_inode(dir->i_sb, ino);
 555         d_instantiate(dentry, inode);
 556
 557         if (dir == dir->i_sb->s_root->d_inode)
 558                 dentry->d_op = &autofs4_root_dentry_operations;
 559         else
 560                 dentry->d_op = &autofs4_dentry_operations;
 561
 562         dentry->d_fsdata = ino;
 563         ino->dentry = dget(dentry);
 564         ino->inode = inode;
 565
 566         dir->i_mtime = CURRENT_TIME;
 567
 568         return 0;
 569 }
 570
 571 /*
 572  * NOTE!
 573  *
 574  * Normal filesystems would do a "d_delete()" to tell the VFS dcache
 575  * that the file no longer exists. However, doing that means that the
 576  * VFS layer can turn the dentry into a negative dentry.  We don't want
 577  * this, because since the unlink is probably the result of an expire.
 578  * We simply d_drop it, which allows the dentry lookup to remount it
 579  * if necessary.
 580  *
 581  * If a process is blocked on the dentry waiting for the expire to finish,
 582  * it will invalidate the dentry and try to mount with a new one.
 583  *
 584  * Also see autofs4_dir_rmdir()..
 585  */
 586 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
 587 {
 588         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 589         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 590
 591         /* This allows root to remove symlinks */
 592         if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
 593                 return -EACCES;
 594
 595         dput(ino->dentry);
 596
 597         dentry->d_inode->i_size = 0;
 598         dentry->d_inode->i_nlink = 0;
 599
 600         dir->i_mtime = CURRENT_TIME;
 601
 602         d_drop(dentry);
 603
 604         return 0;
 605 }
 606
 607 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 608 {
 609         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 610         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 611
 612         if (!autofs4_oz_mode(sbi))
 613                 return -EACCES;
 614
 615         spin_lock(&dcache_lock);
 616         if (!list_empty(&dentry->d_subdirs)) {
 617                 spin_unlock(&dcache_lock);
 618                 return -ENOTEMPTY;
 619         }
 620         spin_lock(&dentry->d_lock);
 621         __d_drop(dentry);
 622         spin_unlock(&dentry->d_lock);
 623         spin_unlock(&dcache_lock);
 624
 625         dput(ino->dentry);
 626
 627         dentry->d_inode->i_size = 0;
 628         dentry->d_inode->i_nlink = 0;
 629
 630         if (dir->i_nlink)
 631                 dir->i_nlink--;
 632
 633         return 0;
 634 }
 635
 636 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 637 {
 638         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 639         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 640         struct inode *inode;
 641
 642         if ( !autofs4_oz_mode(sbi) )
 643                 return -EACCES;
 644
 645         DPRINTK("dentry %p, creating %.*s",
 646                 dentry, dentry->d_name.len, dentry->d_name.name);
 647
 648         ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
 649         if (ino == NULL)
 650                 return -ENOSPC;
 651
 652         inode = autofs4_get_inode(dir->i_sb, ino);
 653         d_instantiate(dentry, inode);
 654
 655         if (dir == dir->i_sb->s_root->d_inode)
 656                 dentry->d_op = &autofs4_root_dentry_operations;
 657         else
 658                 dentry->d_op = &autofs4_dentry_operations;
 659
 660         dentry->d_fsdata = ino;
 661         ino->dentry = dget(dentry);
 662         ino->inode = inode;
 663         dir->i_nlink++;
 664         dir->i_mtime = CURRENT_TIME;
 665
 666         return 0;
 667 }
 668
 669 /* Get/set timeout ioctl() operation */
 670 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
 671                                          unsigned long __user *p)
 672 {
 673         int rv;
 674         unsigned long ntimeout;
 675
 676         if ( (rv = get_user(ntimeout, p)) ||
 677              (rv = put_user(sbi->exp_timeout/HZ, p)) )
 678                 return rv;
 679
 680         if ( ntimeout > ULONG_MAX/HZ )
 681                 sbi->exp_timeout = 0;
 682         else
 683                 sbi->exp_timeout = ntimeout * HZ;
 684
 685         return 0;
 686 }
 687
 688 /* Return protocol version */
 689 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
 690 {
 691         return put_user(sbi->version, p);
 692 }
 693
 694 /* Return protocol sub version */
 695 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
 696 {
 697         return put_user(sbi->sub_version, p);
 698 }
 699
 700 /*
 701  * Tells the daemon whether we need to reghost or not. Also, clears
 702  * the reghost_needed flag.
 703  */
 704 static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
 705 {
 706         int status;
 707
 708         DPRINTK("returning %d", sbi->needs_reghost);
 709
 710         status = put_user(sbi->needs_reghost, p);
 711         if ( status )
 712                 return status;
 713
 714         sbi->needs_reghost = 0;
 715         return 0;
 716 }
 717
 718 /*
 719  * Enable / Disable reghosting ioctl() operation
 720  */
 721 static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
 722 {
 723         int status;
 724         int val;
 725
 726         status = get_user(val, p);
 727
 728         DPRINTK("reghost = %d", val);
 729
 730         if (status)
 731                 return status;
 732
 733         /* turn on/off reghosting, with the val */
 734         sbi->reghost_enabled = val;
 735         return 0;
 736 }
 737
 738 /*
 739 * Tells the daemon whether it can umount the autofs mount.
 740 */
 741 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
 742 {
 743         int status = 0;
 744
 745         if (may_umount(mnt) == 0)
 746                 status = 1;
 747
 748         DPRINTK("returning %d", status);
 749
 750         status = put_user(status, p);
 751
 752         return status;
 753 }
 754
 755 /* Identify autofs4_dentries - this is so we can tell if there's
 756    an extra dentry refcount or not.  We only hold a refcount on the
 757    dentry if its non-negative (ie, d_inode != NULL)
 758 */
 759 int is_autofs4_dentry(struct dentry *dentry)
 760 {
 761         return dentry && dentry->d_inode &&
 762                 (dentry->d_op == &autofs4_root_dentry_operations ||
 763                  dentry->d_op == &autofs4_dentry_operations) &&
 764                 dentry->d_fsdata != NULL;
 765 }
 766
 767 /*
 768  * ioctl()'s on the root directory is the chief method for the daemon to
 769  * generate kernel reactions
 770  */
 771 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
 772                              unsigned int cmd, unsigned long arg)
 773 {
 774         struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
 775         void __user *p = (void __user *)arg;
 776
 777         DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
 778                 cmd,arg,sbi,process_group(current));
 779
 780         if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
 781              _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
 782                 return -ENOTTY;
 783
 784         if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
 785                 return -EPERM;
 786
 787         switch(cmd) {
 788         case AUTOFS_IOC_READY:  /* Wait queue: go ahead and retry */
 789                 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
 790         case AUTOFS_IOC_FAIL:   /* Wait queue: fail with ENOENT */
 791                 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
 792         case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
 793                 autofs4_catatonic_mode(sbi);
 794                 return 0;
 795         case AUTOFS_IOC_PROTOVER: /* Get protocol version */
 796                 return autofs4_get_protover(sbi, p);
 797         case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
 798                 return autofs4_get_protosubver(sbi, p);
 799         case AUTOFS_IOC_SETTIMEOUT:
 800                 return autofs4_get_set_timeout(sbi, p);
 801
 802         case AUTOFS_IOC_TOGGLEREGHOST:
 803                 return autofs4_toggle_reghost(sbi, p);
 804         case AUTOFS_IOC_ASKREGHOST:
 805                 return autofs4_ask_reghost(sbi, p);
 806
 807         case AUTOFS_IOC_ASKUMOUNT:
 808                 return autofs4_ask_umount(filp->f_vfsmnt, p);
 809
 810         /* return a single thing to expire */
 811         case AUTOFS_IOC_EXPIRE:
 812                 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p);
 813         /* same as above, but can send multiple expires through pipe */
 814         case AUTOFS_IOC_EXPIRE_MULTI:
 815                 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p);
 816
 817         default:
 818                 return -ENOSYS;
 819         }
 820 }