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 2001-2006 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/capability.h>
  16 #include <linux/errno.h>
  17 #include <linux/stat.h>
  18 #include <linux/param.h>
  19 #include <linux/time.h>
  20 #include <linux/smp_lock.h>
  21 #include "autofs_i.h"
  22
  23 static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
  24 static int autofs4_dir_unlink(struct inode *,struct dentry *);
  25 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
  26 static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
  27 static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
  28 static int autofs4_dir_open(struct inode *inode, struct file *file);
  29 static int autofs4_dir_close(struct inode *inode, struct file *file);
  30 static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
  31 static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
  32 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
  33 static void *autofs4_follow_link(struct dentry *, struct nameidata *);
  34
  35 const struct file_operations autofs4_root_operations = {
  36         .open           = dcache_dir_open,
  37         .release        = dcache_dir_close,
  38         .read           = generic_read_dir,
  39         .readdir        = autofs4_root_readdir,
  40         .ioctl          = autofs4_root_ioctl,
  41 };
  42
  43 const struct file_operations autofs4_dir_operations = {
  44         .open           = autofs4_dir_open,
  45         .release        = autofs4_dir_close,
  46         .read           = generic_read_dir,
  47         .readdir        = autofs4_dir_readdir,
  48 };
  49
  50 struct inode_operations autofs4_indirect_root_inode_operations = {
  51         .lookup         = autofs4_lookup,
  52         .unlink         = autofs4_dir_unlink,
  53         .symlink        = autofs4_dir_symlink,
  54         .mkdir          = autofs4_dir_mkdir,
  55         .rmdir          = autofs4_dir_rmdir,
  56 };
  57
  58 struct inode_operations autofs4_direct_root_inode_operations = {
  59         .lookup         = autofs4_lookup,
  60         .unlink         = autofs4_dir_unlink,
  61         .mkdir          = autofs4_dir_mkdir,
  62         .rmdir          = autofs4_dir_rmdir,
  63         .follow_link    = autofs4_follow_link,
  64 };
  65
  66 struct inode_operations autofs4_dir_inode_operations = {
  67         .lookup         = autofs4_lookup,
  68         .unlink         = autofs4_dir_unlink,
  69         .symlink        = autofs4_dir_symlink,
  70         .mkdir          = autofs4_dir_mkdir,
  71         .rmdir          = autofs4_dir_rmdir,
  72 };
  73
  74 static int autofs4_root_readdir(struct file *file, void *dirent,
  75                                 filldir_t filldir)
  76 {
  77         struct autofs_sb_info *sbi = autofs4_sbi(file->f_dentry->d_sb);
  78         int oz_mode = autofs4_oz_mode(sbi);
  79
  80         DPRINTK("called, filp->f_pos = %lld", file->f_pos);
  81
  82         /*
  83          * Don't set reghost flag if:
  84          * 1) f_pos is larger than zero -- we've already been here.
  85          * 2) we haven't even enabled reghosting in the 1st place.
  86          * 3) this is the daemon doing a readdir
  87          */
  88         if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled)
  89                 sbi->needs_reghost = 1;
  90
  91         DPRINTK("needs_reghost = %d", sbi->needs_reghost);
  92
  93         return dcache_readdir(file, dirent, filldir);
  94 }
  95
  96 static int autofs4_dir_open(struct inode *inode, struct file *file)
  97 {
  98         struct dentry *dentry = file->f_dentry;
  99         struct vfsmount *mnt = file->f_vfsmnt;
 100         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 101         struct dentry *cursor;
 102         int status;
 103
 104         status = dcache_dir_open(inode, file);
 105         if (status)
 106                 goto out;
 107
 108         cursor = file->private_data;
 109         cursor->d_fsdata = NULL;
 110
 111         DPRINTK("file=%p dentry=%p %.*s",
 112                 file, dentry, dentry->d_name.len, dentry->d_name.name);
 113
 114         if (autofs4_oz_mode(sbi))
 115                 goto out;
 116
 117         if (autofs4_ispending(dentry)) {
 118                 DPRINTK("dentry busy");
 119                 dcache_dir_close(inode, file);
 120                 status = -EBUSY;
 121                 goto out;
 122         }
 123
 124         status = -ENOENT;
 125         if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
 126                 struct nameidata nd;
 127                 int empty, ret;
 128
 129                 /* In case there are stale directory dentrys from a failed mount */
 130                 spin_lock(&dcache_lock);
 131                 empty = list_empty(&dentry->d_subdirs);
 132                 spin_unlock(&dcache_lock);
 133
 134                 if (!empty)
 135                         d_invalidate(dentry);
 136
 137                 nd.flags = LOOKUP_DIRECTORY;
 138                 ret = (dentry->d_op->d_revalidate)(dentry, &nd);
 139
 140                 if (ret <= 0) {
 141                         if (ret < 0)
 142                                 status = ret;
 143                         dcache_dir_close(inode, file);
 144                         goto out;
 145                 }
 146         }
 147
 148         if (d_mountpoint(dentry)) {
 149                 struct file *fp = NULL;
 150                 struct vfsmount *fp_mnt = mntget(mnt);
 151                 struct dentry *fp_dentry = dget(dentry);
 152
 153                 if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {
 154                         dput(fp_dentry);
 155                         mntput(fp_mnt);
 156                         dcache_dir_close(inode, file);
 157                         goto out;
 158                 }
 159
 160                 fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
 161                 status = PTR_ERR(fp);
 162                 if (IS_ERR(fp)) {
 163                         dcache_dir_close(inode, file);
 164                         goto out;
 165                 }
 166                 cursor->d_fsdata = fp;
 167         }
 168         return 0;
 169 out:
 170         return status;
 171 }
 172
 173 static int autofs4_dir_close(struct inode *inode, struct file *file)
 174 {
 175         struct dentry *dentry = file->f_dentry;
 176         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 177         struct dentry *cursor = file->private_data;
 178         int status = 0;
 179
 180         DPRINTK("file=%p dentry=%p %.*s",
 181                 file, dentry, dentry->d_name.len, dentry->d_name.name);
 182
 183         if (autofs4_oz_mode(sbi))
 184                 goto out;
 185
 186         if (autofs4_ispending(dentry)) {
 187                 DPRINTK("dentry busy");
 188                 status = -EBUSY;
 189                 goto out;
 190         }
 191
 192         if (d_mountpoint(dentry)) {
 193                 struct file *fp = cursor->d_fsdata;
 194                 if (!fp) {
 195                         status = -ENOENT;
 196                         goto out;
 197                 }
 198                 filp_close(fp, current->files);
 199         }
 200 out:
 201         dcache_dir_close(inode, file);
 202         return status;
 203 }
 204
 205 static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
 206 {
 207         struct dentry *dentry = file->f_dentry;
 208         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 209         struct dentry *cursor = file->private_data;
 210         int status;
 211
 212         DPRINTK("file=%p dentry=%p %.*s",
 213                 file, dentry, dentry->d_name.len, dentry->d_name.name);
 214
 215         if (autofs4_oz_mode(sbi))
 216                 goto out;
 217
 218         if (autofs4_ispending(dentry)) {
 219                 DPRINTK("dentry busy");
 220                 return -EBUSY;
 221         }
 222
 223         if (d_mountpoint(dentry)) {
 224                 struct file *fp = cursor->d_fsdata;
 225
 226                 if (!fp)
 227                         return -ENOENT;
 228
 229                 if (!fp->f_op || !fp->f_op->readdir)
 230                         goto out;
 231
 232                 status = vfs_readdir(fp, filldir, dirent);
 233                 file->f_pos = fp->f_pos;
 234                 if (status)
 235                         autofs4_copy_atime(file, fp);
 236                 return status;
 237         }
 238 out:
 239         return dcache_readdir(file, dirent, filldir);
 240 }
 241
 242 static int try_to_fill_dentry(struct dentry *dentry, int flags)
 243 {
 244         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 245         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 246         int status = 0;
 247
 248         /* Block on any pending expiry here; invalidate the dentry
 249            when expiration is done to trigger mount request with a new
 250            dentry */
 251         if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
 252                 DPRINTK("waiting for expire %p name=%.*s",
 253                          dentry, dentry->d_name.len, dentry->d_name.name);
 254
 255                 status = autofs4_wait(sbi, dentry, NFY_NONE);
 256
 257                 DPRINTK("expire done status=%d", status);
 258
 259                 /*
 260                  * If the directory still exists the mount request must
 261                  * continue otherwise it can't be followed at the right
 262                  * time during the walk.
 263                  */
 264                 status = d_invalidate(dentry);
 265                 if (status != -EBUSY)
 266                         return -ENOENT;
 267         }
 268
 269         DPRINTK("dentry=%p %.*s ino=%p",
 270                  dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
 271
 272         /*
 273          * Wait for a pending mount, triggering one if there
 274          * isn't one already
 275          */
 276         if (dentry->d_inode == NULL) {
 277                 DPRINTK("waiting for mount name=%.*s",
 278                          dentry->d_name.len, dentry->d_name.name);
 279
 280                 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
 281
 282                 DPRINTK("mount done status=%d", status);
 283
 284                 /* Turn this into a real negative dentry? */
 285                 if (status == -ENOENT) {
 286                         spin_lock(&dentry->d_lock);
 287                         dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 288                         spin_unlock(&dentry->d_lock);
 289                         return status;
 290                 } else if (status) {
 291                         /* Return a negative dentry, but leave it "pending" */
 292                         return status;
 293                 }
 294         /* Trigger mount for path component or follow link */
 295         } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
 296                         current->link_count) {
 297                 DPRINTK("waiting for mount name=%.*s",
 298                         dentry->d_name.len, dentry->d_name.name);
 299
 300                 spin_lock(&dentry->d_lock);
 301                 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
 302                 spin_unlock(&dentry->d_lock);
 303                 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
 304
 305                 DPRINTK("mount done status=%d", status);
 306
 307                 if (status) {
 308                         spin_lock(&dentry->d_lock);
 309                         dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 310                         spin_unlock(&dentry->d_lock);
 311                         return status;
 312                 }
 313         }
 314
 315         /* Initialize expiry counter after successful mount */
 316         if (ino)
 317                 ino->last_used = jiffies;
 318
 319         spin_lock(&dentry->d_lock);
 320         dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 321         spin_unlock(&dentry->d_lock);
 322         return status;
 323 }
 324
 325 /* For autofs direct mounts the follow link triggers the mount */
 326 static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
 327 {
 328         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 329         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 330         int oz_mode = autofs4_oz_mode(sbi);
 331         unsigned int lookup_type;
 332         int status;
 333
 334         DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d",
 335                 dentry, dentry->d_name.len, dentry->d_name.name, oz_mode,
 336                 nd->flags);
 337
 338         /* If it's our master or we shouldn't trigger a mount we're done */
 339         lookup_type = nd->flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY);
 340         if (oz_mode || !lookup_type)
 341                 goto done;
 342
 343         /* If an expire request is pending wait for it. */
 344         if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
 345                 DPRINTK("waiting for active request %p name=%.*s",
 346                         dentry, dentry->d_name.len, dentry->d_name.name);
 347
 348                 status = autofs4_wait(sbi, dentry, NFY_NONE);
 349
 350                 DPRINTK("request done status=%d", status);
 351         }
 352
 353         /*
 354          * If the dentry contains directories then it is an
 355          * autofs multi-mount with no root mount offset. So
 356          * don't try to mount it again.
 357          */
 358         spin_lock(&dcache_lock);
 359         if (!d_mountpoint(dentry) && __simple_empty(dentry)) {
 360                 spin_unlock(&dcache_lock);
 361
 362                 status = try_to_fill_dentry(dentry, 0);
 363                 if (status)
 364                         goto out_error;
 365
 366                 /*
 367                  * The mount succeeded but if there is no root mount
 368                  * it must be an autofs multi-mount with no root offset
 369                  * so we don't need to follow the mount.
 370                  */
 371                 if (d_mountpoint(dentry)) {
 372                         if (!autofs4_follow_mount(&nd->mnt, &nd->dentry)) {
 373                                 status = -ENOENT;
 374                                 goto out_error;
 375                         }
 376                 }
 377
 378                 goto done;
 379         }
 380         spin_unlock(&dcache_lock);
 381
 382 done:
 383         return NULL;
 384
 385 out_error:
 386         path_release(nd);
 387         return ERR_PTR(status);
 388 }
 389
 390 /*
 391  * Revalidate is called on every cache lookup.  Some of those
 392  * cache lookups may actually happen while the dentry is not
 393  * yet completely filled in, and revalidate has to delay such
 394  * lookups..
 395  */
 396 static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
 397 {
 398         struct inode *dir = dentry->d_parent->d_inode;
 399         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 400         int oz_mode = autofs4_oz_mode(sbi);
 401         int flags = nd ? nd->flags : 0;
 402         int status = 1;
 403
 404         /* Pending dentry */
 405         if (autofs4_ispending(dentry)) {
 406                 /* The daemon never causes a mount to trigger */
 407                 if (oz_mode)
 408                         return 1;
 409
 410                 /*
 411                  * A zero status is success otherwise we have a
 412                  * negative error code.
 413                  */
 414                 status = try_to_fill_dentry(dentry, flags);
 415                 if (status == 0)
 416                                 return 1;
 417
 418                 return status;
 419         }
 420
 421         /* Negative dentry.. invalidate if "old" */
 422         if (dentry->d_inode == NULL)
 423                 return 0;
 424
 425         /* Check for a non-mountpoint directory with no contents */
 426         spin_lock(&dcache_lock);
 427         if (S_ISDIR(dentry->d_inode->i_mode) &&
 428             !d_mountpoint(dentry) &&
 429             __simple_empty(dentry)) {
 430                 DPRINTK("dentry=%p %.*s, emptydir",
 431                          dentry, dentry->d_name.len, dentry->d_name.name);
 432                 spin_unlock(&dcache_lock);
 433                 /* The daemon never causes a mount to trigger */
 434                 if (oz_mode)
 435                         return 1;
 436
 437                 /*
 438                  * A zero status is success otherwise we have a
 439                  * negative error code.
 440                  */
 441                 status = try_to_fill_dentry(dentry, flags);
 442                 if (status == 0)
 443                         return 1;
 444
 445                 return status;
 446         }
 447         spin_unlock(&dcache_lock);
 448
 449         return 1;
 450 }
 451
 452 void autofs4_dentry_release(struct dentry *de)
 453 {
 454         struct autofs_info *inf;
 455
 456         DPRINTK("releasing %p", de);
 457
 458         inf = autofs4_dentry_ino(de);
 459         de->d_fsdata = NULL;
 460
 461         if (inf) {
 462                 inf->dentry = NULL;
 463                 inf->inode = NULL;
 464
 465                 autofs4_free_ino(inf);
 466         }
 467 }
 468
 469 /* For dentries of directories in the root dir */
 470 static struct dentry_operations autofs4_root_dentry_operations = {
 471         .d_revalidate   = autofs4_revalidate,
 472         .d_release      = autofs4_dentry_release,
 473 };
 474
 475 /* For other dentries */
 476 static struct dentry_operations autofs4_dentry_operations = {
 477         .d_revalidate   = autofs4_revalidate,
 478         .d_release      = autofs4_dentry_release,
 479 };
 480
 481 /* Lookups in the root directory */
 482 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 483 {
 484         struct autofs_sb_info *sbi;
 485         int oz_mode;
 486
 487         DPRINTK("name = %.*s",
 488                 dentry->d_name.len, dentry->d_name.name);
 489
 490         /* File name too long to exist */
 491         if (dentry->d_name.len > NAME_MAX)
 492                 return ERR_PTR(-ENAMETOOLONG);
 493
 494         sbi = autofs4_sbi(dir->i_sb);
 495         oz_mode = autofs4_oz_mode(sbi);
 496
 497         DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
 498                  current->pid, process_group(current), sbi->catatonic, oz_mode);
 499
 500         /*
 501          * Mark the dentry incomplete, but add it. This is needed so
 502          * that the VFS layer knows about the dentry, and we can count
 503          * on catching any lookups through the revalidate.
 504          *
 505          * Let all the hard work be done by the revalidate function that
 506          * needs to be able to do this anyway..
 507          *
 508          * We need to do this before we release the directory semaphore.
 509          */
 510         dentry->d_op = &autofs4_root_dentry_operations;
 511
 512         if (!oz_mode) {
 513                 spin_lock(&dentry->d_lock);
 514                 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
 515                 spin_unlock(&dentry->d_lock);
 516         }
 517         dentry->d_fsdata = NULL;
 518         d_add(dentry, NULL);
 519
 520         if (dentry->d_op && dentry->d_op->d_revalidate) {
 521                 mutex_unlock(&dir->i_mutex);
 522                 (dentry->d_op->d_revalidate)(dentry, nd);
 523                 mutex_lock(&dir->i_mutex);
 524         }
 525
 526         /*
 527          * If we are still pending, check if we had to handle
 528          * a signal. If so we can force a restart..
 529          */
 530         if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
 531                 /* See if we were interrupted */
 532                 if (signal_pending(current)) {
 533                         sigset_t *sigset = &current->pending.signal;
 534                         if (sigismember (sigset, SIGKILL) ||
 535                             sigismember (sigset, SIGQUIT) ||
 536                             sigismember (sigset, SIGINT)) {
 537                             return ERR_PTR(-ERESTARTNOINTR);
 538                         }
 539                 }
 540                 spin_lock(&dentry->d_lock);
 541                 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 542                 spin_unlock(&dentry->d_lock);
 543         }
 544
 545         /*
 546          * If this dentry is unhashed, then we shouldn't honour this
 547          * lookup even if the dentry is positive.  Returning ENOENT here
 548          * doesn't do the right thing for all system calls, but it should
 549          * be OK for the operations we permit from an autofs.
 550          */
 551         if (dentry->d_inode && d_unhashed(dentry))
 552                 return ERR_PTR(-ENOENT);
 553
 554         return NULL;
 555 }
 556
 557 static int autofs4_dir_symlink(struct inode *dir,
 558                                struct dentry *dentry,
 559                                const char *symname)
 560 {
 561         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 562         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 563         struct autofs_info *p_ino;
 564         struct inode *inode;
 565         char *cp;
 566
 567         DPRINTK("%s <- %.*s", symname,
 568                 dentry->d_name.len, dentry->d_name.name);
 569
 570         if (!autofs4_oz_mode(sbi))
 571                 return -EACCES;
 572
 573         ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
 574         if (ino == NULL)
 575                 return -ENOSPC;
 576
 577         ino->size = strlen(symname);
 578         ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
 579
 580         if (cp == NULL) {
 581                 kfree(ino);
 582                 return -ENOSPC;
 583         }
 584
 585         strcpy(cp, symname);
 586
 587         inode = autofs4_get_inode(dir->i_sb, ino);
 588         d_instantiate(dentry, inode);
 589
 590         if (dir == dir->i_sb->s_root->d_inode)
 591                 dentry->d_op = &autofs4_root_dentry_operations;
 592         else
 593                 dentry->d_op = &autofs4_dentry_operations;
 594
 595         dentry->d_fsdata = ino;
 596         ino->dentry = dget(dentry);
 597         atomic_inc(&ino->count);
 598         p_ino = autofs4_dentry_ino(dentry->d_parent);
 599         if (p_ino && dentry->d_parent != dentry)
 600                 atomic_inc(&p_ino->count);
 601         ino->inode = inode;
 602
 603         dir->i_mtime = CURRENT_TIME;
 604
 605         return 0;
 606 }
 607
 608 /*
 609  * NOTE!
 610  *
 611  * Normal filesystems would do a "d_delete()" to tell the VFS dcache
 612  * that the file no longer exists. However, doing that means that the
 613  * VFS layer can turn the dentry into a negative dentry.  We don't want
 614  * this, because since the unlink is probably the result of an expire.
 615  * We simply d_drop it, which allows the dentry lookup to remount it
 616  * if necessary.
 617  *
 618  * If a process is blocked on the dentry waiting for the expire to finish,
 619  * it will invalidate the dentry and try to mount with a new one.
 620  *
 621  * Also see autofs4_dir_rmdir()..
 622  */
 623 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
 624 {
 625         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 626         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 627         struct autofs_info *p_ino;
 628
 629         /* This allows root to remove symlinks */
 630         if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
 631                 return -EACCES;
 632
 633         if (atomic_dec_and_test(&ino->count)) {
 634                 p_ino = autofs4_dentry_ino(dentry->d_parent);
 635                 if (p_ino && dentry->d_parent != dentry)
 636                         atomic_dec(&p_ino->count);
 637         }
 638         dput(ino->dentry);
 639
 640         dentry->d_inode->i_size = 0;
 641         clear_nlink(dentry->d_inode);
 642
 643         dir->i_mtime = CURRENT_TIME;
 644
 645         d_drop(dentry);
 646
 647         return 0;
 648 }
 649
 650 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 651 {
 652         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 653         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 654         struct autofs_info *p_ino;
 655
 656         if (!autofs4_oz_mode(sbi))
 657                 return -EACCES;
 658
 659         spin_lock(&dcache_lock);
 660         if (!list_empty(&dentry->d_subdirs)) {
 661                 spin_unlock(&dcache_lock);
 662                 return -ENOTEMPTY;
 663         }
 664         spin_lock(&dentry->d_lock);
 665         __d_drop(dentry);
 666         spin_unlock(&dentry->d_lock);
 667         spin_unlock(&dcache_lock);
 668
 669         if (atomic_dec_and_test(&ino->count)) {
 670                 p_ino = autofs4_dentry_ino(dentry->d_parent);
 671                 if (p_ino && dentry->d_parent != dentry)
 672                         atomic_dec(&p_ino->count);
 673         }
 674         dput(ino->dentry);
 675         dentry->d_inode->i_size = 0;
 676         clear_nlink(dentry->d_inode);
 677
 678         if (dir->i_nlink)
 679                 drop_nlink(dir);
 680
 681         return 0;
 682 }
 683
 684 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 685 {
 686         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 687         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 688         struct autofs_info *p_ino;
 689         struct inode *inode;
 690
 691         if ( !autofs4_oz_mode(sbi) )
 692                 return -EACCES;
 693
 694         DPRINTK("dentry %p, creating %.*s",
 695                 dentry, dentry->d_name.len, dentry->d_name.name);
 696
 697         ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
 698         if (ino == NULL)
 699                 return -ENOSPC;
 700
 701         inode = autofs4_get_inode(dir->i_sb, ino);
 702         d_instantiate(dentry, inode);
 703
 704         if (dir == dir->i_sb->s_root->d_inode)
 705                 dentry->d_op = &autofs4_root_dentry_operations;
 706         else
 707                 dentry->d_op = &autofs4_dentry_operations;
 708
 709         dentry->d_fsdata = ino;
 710         ino->dentry = dget(dentry);
 711         atomic_inc(&ino->count);
 712         p_ino = autofs4_dentry_ino(dentry->d_parent);
 713         if (p_ino && dentry->d_parent != dentry)
 714                 atomic_inc(&p_ino->count);
 715         ino->inode = inode;
 716         inc_nlink(dir);
 717         dir->i_mtime = CURRENT_TIME;
 718
 719         return 0;
 720 }
 721
 722 /* Get/set timeout ioctl() operation */
 723 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
 724                                          unsigned long __user *p)
 725 {
 726         int rv;
 727         unsigned long ntimeout;
 728
 729         if ( (rv = get_user(ntimeout, p)) ||
 730              (rv = put_user(sbi->exp_timeout/HZ, p)) )
 731                 return rv;
 732
 733         if ( ntimeout > ULONG_MAX/HZ )
 734                 sbi->exp_timeout = 0;
 735         else
 736                 sbi->exp_timeout = ntimeout * HZ;
 737
 738         return 0;
 739 }
 740
 741 /* Return protocol version */
 742 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
 743 {
 744         return put_user(sbi->version, p);
 745 }
 746
 747 /* Return protocol sub version */
 748 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
 749 {
 750         return put_user(sbi->sub_version, p);
 751 }
 752
 753 /*
 754  * Tells the daemon whether we need to reghost or not. Also, clears
 755  * the reghost_needed flag.
 756  */
 757 static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
 758 {
 759         int status;
 760
 761         DPRINTK("returning %d", sbi->needs_reghost);
 762
 763         status = put_user(sbi->needs_reghost, p);
 764         if ( status )
 765                 return status;
 766
 767         sbi->needs_reghost = 0;
 768         return 0;
 769 }
 770
 771 /*
 772  * Enable / Disable reghosting ioctl() operation
 773  */
 774 static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
 775 {
 776         int status;
 777         int val;
 778
 779         status = get_user(val, p);
 780
 781         DPRINTK("reghost = %d", val);
 782
 783         if (status)
 784                 return status;
 785
 786         /* turn on/off reghosting, with the val */
 787         sbi->reghost_enabled = val;
 788         return 0;
 789 }
 790
 791 /*
 792 * Tells the daemon whether it can umount the autofs mount.
 793 */
 794 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
 795 {
 796         int status = 0;
 797
 798         if (may_umount(mnt))
 799                 status = 1;
 800
 801         DPRINTK("returning %d", status);
 802
 803         status = put_user(status, p);
 804
 805         return status;
 806 }
 807
 808 /* Identify autofs4_dentries - this is so we can tell if there's
 809    an extra dentry refcount or not.  We only hold a refcount on the
 810    dentry if its non-negative (ie, d_inode != NULL)
 811 */
 812 int is_autofs4_dentry(struct dentry *dentry)
 813 {
 814         return dentry && dentry->d_inode &&
 815                 (dentry->d_op == &autofs4_root_dentry_operations ||
 816                  dentry->d_op == &autofs4_dentry_operations) &&
 817                 dentry->d_fsdata != NULL;
 818 }
 819
 820 /*
 821  * ioctl()'s on the root directory is the chief method for the daemon to
 822  * generate kernel reactions
 823  */
 824 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
 825                              unsigned int cmd, unsigned long arg)
 826 {
 827         struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
 828         void __user *p = (void __user *)arg;
 829
 830         DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
 831                 cmd,arg,sbi,process_group(current));
 832
 833         if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
 834              _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
 835                 return -ENOTTY;
 836
 837         if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
 838                 return -EPERM;
 839
 840         switch(cmd) {
 841         case AUTOFS_IOC_READY:  /* Wait queue: go ahead and retry */
 842                 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
 843         case AUTOFS_IOC_FAIL:   /* Wait queue: fail with ENOENT */
 844                 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
 845         case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
 846                 autofs4_catatonic_mode(sbi);
 847                 return 0;
 848         case AUTOFS_IOC_PROTOVER: /* Get protocol version */
 849                 return autofs4_get_protover(sbi, p);
 850         case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
 851                 return autofs4_get_protosubver(sbi, p);
 852         case AUTOFS_IOC_SETTIMEOUT:
 853                 return autofs4_get_set_timeout(sbi, p);
 854
 855         case AUTOFS_IOC_TOGGLEREGHOST:
 856                 return autofs4_toggle_reghost(sbi, p);
 857         case AUTOFS_IOC_ASKREGHOST:
 858                 return autofs4_ask_reghost(sbi, p);
 859
 860         case AUTOFS_IOC_ASKUMOUNT:
 861                 return autofs4_ask_umount(filp->f_vfsmnt, p);
 862
 863         /* return a single thing to expire */
 864         case AUTOFS_IOC_EXPIRE:
 865                 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p);
 866         /* same as above, but can send multiple expires through pipe */
 867         case AUTOFS_IOC_EXPIRE_MULTI:
 868                 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p);
 869
 870         default:
 871                 return -ENOSYS;
 872         }
 873 }