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