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/slab.h>
  19 #include <linux/param.h>
  20 #include <linux/time.h>
  21 #include <linux/compat.h>
  22 #include <linux/mutex.h>
  23
  24 #include "autofs_i.h"
  25
  26 static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
  27 static int autofs4_dir_unlink(struct inode *,struct dentry *);
  28 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
  29 static int autofs4_dir_mkdir(struct inode *,struct dentry *,umode_t);
  30 static long autofs4_root_ioctl(struct file *,unsigned int,unsigned long);
  31 #ifdef CONFIG_COMPAT
  32 static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long);
  33 #endif
  34 static int autofs4_dir_open(struct inode *inode, struct file *file);
  35 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, unsigned int);
  36 static struct vfsmount *autofs4_d_automount(struct path *);
  37 static int autofs4_d_manage(struct dentry *, bool);
  38 static void autofs4_dentry_release(struct dentry *);
  39
  40 const struct file_operations autofs4_root_operations = {
  41         .open           = dcache_dir_open,
  42         .release        = dcache_dir_close,
  43         .read           = generic_read_dir,
  44         .readdir        = dcache_readdir,
  45         .llseek         = dcache_dir_lseek,
  46         .unlocked_ioctl = autofs4_root_ioctl,
  47 #ifdef CONFIG_COMPAT
  48         .compat_ioctl   = autofs4_root_compat_ioctl,
  49 #endif
  50 };
  51
  52 const struct file_operations autofs4_dir_operations = {
  53         .open           = autofs4_dir_open,
  54         .release        = dcache_dir_close,
  55         .read           = generic_read_dir,
  56         .readdir        = dcache_readdir,
  57         .llseek         = dcache_dir_lseek,
  58 };
  59
  60 const struct inode_operations autofs4_dir_inode_operations = {
  61         .lookup         = autofs4_lookup,
  62         .unlink         = autofs4_dir_unlink,
  63         .symlink        = autofs4_dir_symlink,
  64         .mkdir          = autofs4_dir_mkdir,
  65         .rmdir          = autofs4_dir_rmdir,
  66 };
  67
  68 const struct dentry_operations autofs4_dentry_operations = {
  69         .d_automount    = autofs4_d_automount,
  70         .d_manage       = autofs4_d_manage,
  71         .d_release      = autofs4_dentry_release,
  72 };
  73
  74 static void autofs4_add_active(struct dentry *dentry)
  75 {
  76         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
  77         struct autofs_info *ino = autofs4_dentry_ino(dentry);
  78         if (ino) {
  79                 spin_lock(&sbi->lookup_lock);
  80                 if (!ino->active_count) {
  81                         if (list_empty(&ino->active))
  82                                 list_add(&ino->active, &sbi->active_list);
  83                 }
  84                 ino->active_count++;
  85                 spin_unlock(&sbi->lookup_lock);
  86         }
  87         return;
  88 }
  89
  90 static void autofs4_del_active(struct dentry *dentry)
  91 {
  92         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
  93         struct autofs_info *ino = autofs4_dentry_ino(dentry);
  94         if (ino) {
  95                 spin_lock(&sbi->lookup_lock);
  96                 ino->active_count--;
  97                 if (!ino->active_count) {
  98                         if (!list_empty(&ino->active))
  99                                 list_del_init(&ino->active);
 100                 }
 101                 spin_unlock(&sbi->lookup_lock);
 102         }
 103         return;
 104 }
 105
 106 static int autofs4_dir_open(struct inode *inode, struct file *file)
 107 {
 108         struct dentry *dentry = file->f_path.dentry;
 109         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 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         /*
 118          * An empty directory in an autofs file system is always a
 119          * mount point. The daemon must have failed to mount this
 120          * during lookup so it doesn't exist. This can happen, for
 121          * example, if user space returns an incorrect status for a
 122          * mount request. Otherwise we're doing a readdir on the
 123          * autofs file system so just let the libfs routines handle
 124          * it.
 125          */
 126         spin_lock(&sbi->lookup_lock);
 127         if (!d_mountpoint(dentry) && simple_empty(dentry)) {
 128                 spin_unlock(&sbi->lookup_lock);
 129                 return -ENOENT;
 130         }
 131         spin_unlock(&sbi->lookup_lock);
 132
 133 out:
 134         return dcache_dir_open(inode, file);
 135 }
 136
 137 static void autofs4_dentry_release(struct dentry *de)
 138 {
 139         struct autofs_info *ino = autofs4_dentry_ino(de);
 140         struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
 141
 142         DPRINTK("releasing %p", de);
 143
 144         if (!ino)
 145                 return;
 146
 147         if (sbi) {
 148                 spin_lock(&sbi->lookup_lock);
 149                 if (!list_empty(&ino->active))
 150                         list_del(&ino->active);
 151                 if (!list_empty(&ino->expiring))
 152                         list_del(&ino->expiring);
 153                 spin_unlock(&sbi->lookup_lock);
 154         }
 155
 156         autofs4_free_ino(ino);
 157 }
 158
 159 static struct dentry *autofs4_lookup_active(struct dentry *dentry)
 160 {
 161         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 162         struct dentry *parent = dentry->d_parent;
 163         struct qstr *name = &dentry->d_name;
 164         unsigned int len = name->len;
 165         unsigned int hash = name->hash;
 166         const unsigned char *str = name->name;
 167         struct list_head *p, *head;
 168
 169         spin_lock(&sbi->lookup_lock);
 170         head = &sbi->active_list;
 171         list_for_each(p, head) {
 172                 struct autofs_info *ino;
 173                 struct dentry *active;
 174                 struct qstr *qstr;
 175
 176                 ino = list_entry(p, struct autofs_info, active);
 177                 active = ino->dentry;
 178
 179                 spin_lock(&active->d_lock);
 180
 181                 /* Already gone? */
 182                 if (active->d_count == 0)
 183                         goto next;
 184
 185                 qstr = &active->d_name;
 186
 187                 if (active->d_name.hash != hash)
 188                         goto next;
 189                 if (active->d_parent != parent)
 190                         goto next;
 191
 192                 if (qstr->len != len)
 193                         goto next;
 194                 if (memcmp(qstr->name, str, len))
 195                         goto next;
 196
 197                 if (d_unhashed(active)) {
 198                         dget_dlock(active);
 199                         spin_unlock(&active->d_lock);
 200                         spin_unlock(&sbi->lookup_lock);
 201                         return active;
 202                 }
 203 next:
 204                 spin_unlock(&active->d_lock);
 205         }
 206         spin_unlock(&sbi->lookup_lock);
 207
 208         return NULL;
 209 }
 210
 211 static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
 212 {
 213         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 214         struct dentry *parent = dentry->d_parent;
 215         struct qstr *name = &dentry->d_name;
 216         unsigned int len = name->len;
 217         unsigned int hash = name->hash;
 218         const unsigned char *str = name->name;
 219         struct list_head *p, *head;
 220
 221         spin_lock(&sbi->lookup_lock);
 222         head = &sbi->expiring_list;
 223         list_for_each(p, head) {
 224                 struct autofs_info *ino;
 225                 struct dentry *expiring;
 226                 struct qstr *qstr;
 227
 228                 ino = list_entry(p, struct autofs_info, expiring);
 229                 expiring = ino->dentry;
 230
 231                 spin_lock(&expiring->d_lock);
 232
 233                 /* Bad luck, we've already been dentry_iput */
 234                 if (!expiring->d_inode)
 235                         goto next;
 236
 237                 qstr = &expiring->d_name;
 238
 239                 if (expiring->d_name.hash != hash)
 240                         goto next;
 241                 if (expiring->d_parent != parent)
 242                         goto next;
 243
 244                 if (qstr->len != len)
 245                         goto next;
 246                 if (memcmp(qstr->name, str, len))
 247                         goto next;
 248
 249                 if (d_unhashed(expiring)) {
 250                         dget_dlock(expiring);
 251                         spin_unlock(&expiring->d_lock);
 252                         spin_unlock(&sbi->lookup_lock);
 253                         return expiring;
 254                 }
 255 next:
 256                 spin_unlock(&expiring->d_lock);
 257         }
 258         spin_unlock(&sbi->lookup_lock);
 259
 260         return NULL;
 261 }
 262
 263 static int autofs4_mount_wait(struct dentry *dentry)
 264 {
 265         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 266         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 267         int status = 0;
 268
 269         if (ino->flags & AUTOFS_INF_PENDING) {
 270                 DPRINTK("waiting for mount name=%.*s",
 271                         dentry->d_name.len, dentry->d_name.name);
 272                 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
 273                 DPRINTK("mount wait done status=%d", status);
 274         }
 275         ino->last_used = jiffies;
 276         return status;
 277 }
 278
 279 static int do_expire_wait(struct dentry *dentry)
 280 {
 281         struct dentry *expiring;
 282
 283         expiring = autofs4_lookup_expiring(dentry);
 284         if (!expiring)
 285                 return autofs4_expire_wait(dentry);
 286         else {
 287                 /*
 288                  * If we are racing with expire the request might not
 289                  * be quite complete, but the directory has been removed
 290                  * so it must have been successful, just wait for it.
 291                  */
 292                 autofs4_expire_wait(expiring);
 293                 autofs4_del_expiring(expiring);
 294                 dput(expiring);
 295         }
 296         return 0;
 297 }
 298
 299 static struct dentry *autofs4_mountpoint_changed(struct path *path)
 300 {
 301         struct dentry *dentry = path->dentry;
 302         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 303
 304         /*
 305          * If this is an indirect mount the dentry could have gone away
 306          * as a result of an expire and a new one created.
 307          */
 308         if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) {
 309                 struct dentry *parent = dentry->d_parent;
 310                 struct autofs_info *ino;
 311                 struct dentry *new = d_lookup(parent, &dentry->d_name);
 312                 if (!new)
 313                         return NULL;
 314                 ino = autofs4_dentry_ino(new);
 315                 ino->last_used = jiffies;
 316                 dput(path->dentry);
 317                 path->dentry = new;
 318         }
 319         return path->dentry;
 320 }
 321
 322 static struct vfsmount *autofs4_d_automount(struct path *path)
 323 {
 324         struct dentry *dentry = path->dentry;
 325         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 326         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 327         int status;
 328
 329         DPRINTK("dentry=%p %.*s",
 330                 dentry, dentry->d_name.len, dentry->d_name.name);
 331
 332         /* The daemon never triggers a mount. */
 333         if (autofs4_oz_mode(sbi))
 334                 return NULL;
 335
 336         /*
 337          * If an expire request is pending everyone must wait.
 338          * If the expire fails we're still mounted so continue
 339          * the follow and return. A return of -EAGAIN (which only
 340          * happens with indirect mounts) means the expire completed
 341          * and the directory was removed, so just go ahead and try
 342          * the mount.
 343          */
 344         status = do_expire_wait(dentry);
 345         if (status && status != -EAGAIN)
 346                 return NULL;
 347
 348         /* Callback to the daemon to perform the mount or wait */
 349         spin_lock(&sbi->fs_lock);
 350         if (ino->flags & AUTOFS_INF_PENDING) {
 351                 spin_unlock(&sbi->fs_lock);
 352                 status = autofs4_mount_wait(dentry);
 353                 if (status)
 354                         return ERR_PTR(status);
 355                 goto done;
 356         }
 357
 358         /*
 359          * If the dentry is a symlink it's equivalent to a directory
 360          * having d_mountpoint() true, so there's no need to call back
 361          * to the daemon.
 362          */
 363         if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)) {
 364                 spin_unlock(&sbi->fs_lock);
 365                 goto done;
 366         }
 367
 368         if (!d_mountpoint(dentry)) {
 369                 /*
 370                  * It's possible that user space hasn't removed directories
 371                  * after umounting a rootless multi-mount, although it
 372                  * should. For v5 have_submounts() is sufficient to handle
 373                  * this because the leaves of the directory tree under the
 374                  * mount never trigger mounts themselves (they have an autofs
 375                  * trigger mount mounted on them). But v4 pseudo direct mounts
 376                  * do need the leaves to to trigger mounts. In this case we
 377                  * have no choice but to use the list_empty() check and
 378                  * require user space behave.
 379                  */
 380                 if (sbi->version > 4) {
 381                         if (have_submounts(dentry)) {
 382                                 spin_unlock(&sbi->fs_lock);
 383                                 goto done;
 384                         }
 385                 } else {
 386                         if (!simple_empty(dentry))
 387                                 goto done;
 388                 }
 389                 ino->flags |= AUTOFS_INF_PENDING;
 390                 spin_unlock(&sbi->fs_lock);
 391                 status = autofs4_mount_wait(dentry);
 392                 spin_lock(&sbi->fs_lock);
 393                 ino->flags &= ~AUTOFS_INF_PENDING;
 394                 if (status) {
 395                         spin_unlock(&sbi->fs_lock);
 396                         return ERR_PTR(status);
 397                 }
 398         }
 399         spin_unlock(&sbi->fs_lock);
 400 done:
 401         /* Mount succeeded, check if we ended up with a new dentry */
 402         dentry = autofs4_mountpoint_changed(path);
 403         if (!dentry)
 404                 return ERR_PTR(-ENOENT);
 405
 406         return NULL;
 407 }
 408
 409 int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
 410 {
 411         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 412         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 413         int status;
 414
 415         DPRINTK("dentry=%p %.*s",
 416                 dentry, dentry->d_name.len, dentry->d_name.name);
 417
 418         /* The daemon never waits. */
 419         if (autofs4_oz_mode(sbi)) {
 420                 if (rcu_walk)
 421                         return 0;
 422                 if (!d_mountpoint(dentry))
 423                         return -EISDIR;
 424                 return 0;
 425         }
 426
 427         /* We need to sleep, so we need pathwalk to be in ref-mode */
 428         if (rcu_walk)
 429                 return -ECHILD;
 430
 431         /* Wait for pending expires */
 432         do_expire_wait(dentry);
 433
 434         /*
 435          * This dentry may be under construction so wait on mount
 436          * completion.
 437          */
 438         status = autofs4_mount_wait(dentry);
 439         if (status)
 440                 return status;
 441
 442         spin_lock(&sbi->fs_lock);
 443         /*
 444          * If the dentry has been selected for expire while we slept
 445          * on the lock then it might go away. We'll deal with that in
 446          * ->d_automount() and wait on a new mount if the expire
 447          * succeeds or return here if it doesn't (since there's no
 448          * mount to follow with a rootless multi-mount).
 449          */
 450         if (!(ino->flags & AUTOFS_INF_EXPIRING)) {
 451                 /*
 452                  * Any needed mounting has been completed and the path
 453                  * updated so check if this is a rootless multi-mount so
 454                  * we can avoid needless calls ->d_automount() and avoid
 455                  * an incorrect ELOOP error return.
 456                  */
 457                 if ((!d_mountpoint(dentry) && !simple_empty(dentry)) ||
 458                     (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)))
 459                         status = -EISDIR;
 460         }
 461         spin_unlock(&sbi->fs_lock);
 462
 463         return status;
 464 }
 465
 466 /* Lookups in the root directory */
 467 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 468 {
 469         struct autofs_sb_info *sbi;
 470         struct autofs_info *ino;
 471         struct dentry *active;
 472
 473         DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name);
 474
 475         /* File name too long to exist */
 476         if (dentry->d_name.len > NAME_MAX)
 477                 return ERR_PTR(-ENAMETOOLONG);
 478
 479         sbi = autofs4_sbi(dir->i_sb);
 480
 481         DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
 482                 current->pid, task_pgrp_nr(current), sbi->catatonic,
 483                 autofs4_oz_mode(sbi));
 484
 485         active = autofs4_lookup_active(dentry);
 486         if (active) {
 487                 return active;
 488         } else {
 489                 /*
 490                  * A dentry that is not within the root can never trigger a
 491                  * mount operation, unless the directory already exists, so we
 492                  * can return fail immediately.  The daemon however does need
 493                  * to create directories within the file system.
 494                  */
 495                 if (!autofs4_oz_mode(sbi) && !IS_ROOT(dentry->d_parent))
 496                         return ERR_PTR(-ENOENT);
 497
 498                 /* Mark entries in the root as mount triggers */
 499                 if (autofs_type_indirect(sbi->type) && IS_ROOT(dentry->d_parent))
 500                         __managed_dentry_set_managed(dentry);
 501
 502                 ino = autofs4_new_ino(sbi);
 503                 if (!ino)
 504                         return ERR_PTR(-ENOMEM);
 505
 506                 dentry->d_fsdata = ino;
 507                 ino->dentry = dentry;
 508
 509                 autofs4_add_active(dentry);
 510
 511                 d_instantiate(dentry, NULL);
 512         }
 513         return NULL;
 514 }
 515
 516 static int autofs4_dir_symlink(struct inode *dir,
 517                                struct dentry *dentry,
 518                                const char *symname)
 519 {
 520         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 521         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 522         struct autofs_info *p_ino;
 523         struct inode *inode;
 524         size_t size = strlen(symname);
 525         char *cp;
 526
 527         DPRINTK("%s <- %.*s", symname,
 528                 dentry->d_name.len, dentry->d_name.name);
 529
 530         if (!autofs4_oz_mode(sbi))
 531                 return -EACCES;
 532
 533         BUG_ON(!ino);
 534
 535         autofs4_clean_ino(ino);
 536
 537         autofs4_del_active(dentry);
 538
 539         cp = kmalloc(size + 1, GFP_KERNEL);
 540         if (!cp)
 541                 return -ENOMEM;
 542
 543         strcpy(cp, symname);
 544
 545         inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555);
 546         if (!inode) {
 547                 kfree(cp);
 548                 if (!dentry->d_fsdata)
 549                         kfree(ino);
 550                 return -ENOMEM;
 551         }
 552         inode->i_private = cp;
 553         inode->i_size = size;
 554         d_add(dentry, inode);
 555
 556         dget(dentry);
 557         atomic_inc(&ino->count);
 558         p_ino = autofs4_dentry_ino(dentry->d_parent);
 559         if (p_ino && dentry->d_parent != dentry)
 560                 atomic_inc(&p_ino->count);
 561
 562         dir->i_mtime = CURRENT_TIME;
 563
 564         return 0;
 565 }
 566
 567 /*
 568  * NOTE!
 569  *
 570  * Normal filesystems would do a "d_delete()" to tell the VFS dcache
 571  * that the file no longer exists. However, doing that means that the
 572  * VFS layer can turn the dentry into a negative dentry.  We don't want
 573  * this, because the unlink is probably the result of an expire.
 574  * We simply d_drop it and add it to a expiring list in the super block,
 575  * which allows the dentry lookup to check for an incomplete expire.
 576  *
 577  * If a process is blocked on the dentry waiting for the expire to finish,
 578  * it will invalidate the dentry and try to mount with a new one.
 579  *
 580  * Also see autofs4_dir_rmdir()..
 581  */
 582 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
 583 {
 584         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 585         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 586         struct autofs_info *p_ino;
 587
 588         /* This allows root to remove symlinks */
 589         if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
 590                 return -EACCES;
 591
 592         if (atomic_dec_and_test(&ino->count)) {
 593                 p_ino = autofs4_dentry_ino(dentry->d_parent);
 594                 if (p_ino && dentry->d_parent != dentry)
 595                         atomic_dec(&p_ino->count);
 596         }
 597         dput(ino->dentry);
 598
 599         dentry->d_inode->i_size = 0;
 600         clear_nlink(dentry->d_inode);
 601
 602         dir->i_mtime = CURRENT_TIME;
 603
 604         spin_lock(&sbi->lookup_lock);
 605         __autofs4_add_expiring(dentry);
 606         d_drop(dentry);
 607         spin_unlock(&sbi->lookup_lock);
 608
 609         return 0;
 610 }
 611
 612 /*
 613  * Version 4 of autofs provides a pseudo direct mount implementation
 614  * that relies on directories at the leaves of a directory tree under
 615  * an indirect mount to trigger mounts. To allow for this we need to
 616  * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves
 617  * of the directory tree. There is no need to clear the automount flag
 618  * following a mount or restore it after an expire because these mounts
 619  * are always covered. However, it is necessary to ensure that these
 620  * flags are clear on non-empty directories to avoid unnecessary calls
 621  * during path walks.
 622  */
 623 static void autofs_set_leaf_automount_flags(struct dentry *dentry)
 624 {
 625         struct dentry *parent;
 626
 627         /* root and dentrys in the root are already handled */
 628         if (IS_ROOT(dentry->d_parent))
 629                 return;
 630
 631         managed_dentry_set_managed(dentry);
 632
 633         parent = dentry->d_parent;
 634         /* only consider parents below dentrys in the root */
 635         if (IS_ROOT(parent->d_parent))
 636                 return;
 637         managed_dentry_clear_managed(parent);
 638         return;
 639 }
 640
 641 static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
 642 {
 643         struct list_head *d_child;
 644         struct dentry *parent;
 645
 646         /* flags for dentrys in the root are handled elsewhere */
 647         if (IS_ROOT(dentry->d_parent))
 648                 return;
 649
 650         managed_dentry_clear_managed(dentry);
 651
 652         parent = dentry->d_parent;
 653         /* only consider parents below dentrys in the root */
 654         if (IS_ROOT(parent->d_parent))
 655                 return;
 656         d_child = &dentry->d_u.d_child;
 657         /* Set parent managed if it's becoming empty */
 658         if (d_child->next == &parent->d_subdirs &&
 659             d_child->prev == &parent->d_subdirs)
 660                 managed_dentry_set_managed(parent);
 661         return;
 662 }
 663
 664 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 665 {
 666         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 667         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 668         struct autofs_info *p_ino;
 669
 670         DPRINTK("dentry %p, removing %.*s",
 671                 dentry, dentry->d_name.len, dentry->d_name.name);
 672
 673         if (!autofs4_oz_mode(sbi))
 674                 return -EACCES;
 675
 676         spin_lock(&sbi->lookup_lock);
 677         if (!simple_empty(dentry)) {
 678                 spin_unlock(&sbi->lookup_lock);
 679                 return -ENOTEMPTY;
 680         }
 681         __autofs4_add_expiring(dentry);
 682         d_drop(dentry);
 683         spin_unlock(&sbi->lookup_lock);
 684
 685         if (sbi->version < 5)
 686                 autofs_clear_leaf_automount_flags(dentry);
 687
 688         if (atomic_dec_and_test(&ino->count)) {
 689                 p_ino = autofs4_dentry_ino(dentry->d_parent);
 690                 if (p_ino && dentry->d_parent != dentry)
 691                         atomic_dec(&p_ino->count);
 692         }
 693         dput(ino->dentry);
 694         dentry->d_inode->i_size = 0;
 695         clear_nlink(dentry->d_inode);
 696
 697         if (dir->i_nlink)
 698                 drop_nlink(dir);
 699
 700         return 0;
 701 }
 702
 703 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 704 {
 705         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
 706         struct autofs_info *ino = autofs4_dentry_ino(dentry);
 707         struct autofs_info *p_ino;
 708         struct inode *inode;
 709
 710         if (!autofs4_oz_mode(sbi))
 711                 return -EACCES;
 712
 713         DPRINTK("dentry %p, creating %.*s",
 714                 dentry, dentry->d_name.len, dentry->d_name.name);
 715
 716         BUG_ON(!ino);
 717
 718         autofs4_clean_ino(ino);
 719
 720         autofs4_del_active(dentry);
 721
 722         inode = autofs4_get_inode(dir->i_sb, S_IFDIR | 0555);
 723         if (!inode)
 724                 return -ENOMEM;
 725         d_add(dentry, inode);
 726
 727         if (sbi->version < 5)
 728                 autofs_set_leaf_automount_flags(dentry);
 729
 730         dget(dentry);
 731         atomic_inc(&ino->count);
 732         p_ino = autofs4_dentry_ino(dentry->d_parent);
 733         if (p_ino && dentry->d_parent != dentry)
 734                 atomic_inc(&p_ino->count);
 735         inc_nlink(dir);
 736         dir->i_mtime = CURRENT_TIME;
 737
 738         return 0;
 739 }
 740
 741 /* Get/set timeout ioctl() operation */
 742 #ifdef CONFIG_COMPAT
 743 static inline int autofs4_compat_get_set_timeout(struct autofs_sb_info *sbi,
 744                                          compat_ulong_t __user *p)
 745 {
 746         int rv;
 747         unsigned long ntimeout;
 748
 749         if ((rv = get_user(ntimeout, p)) ||
 750              (rv = put_user(sbi->exp_timeout/HZ, p)))
 751                 return rv;
 752
 753         if (ntimeout > UINT_MAX/HZ)
 754                 sbi->exp_timeout = 0;
 755         else
 756                 sbi->exp_timeout = ntimeout * HZ;
 757
 758         return 0;
 759 }
 760 #endif
 761
 762 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
 763                                          unsigned long __user *p)
 764 {
 765         int rv;
 766         unsigned long ntimeout;
 767
 768         if ((rv = get_user(ntimeout, p)) ||
 769              (rv = put_user(sbi->exp_timeout/HZ, p)))
 770                 return rv;
 771
 772         if (ntimeout > ULONG_MAX/HZ)
 773                 sbi->exp_timeout = 0;
 774         else
 775                 sbi->exp_timeout = ntimeout * HZ;
 776
 777         return 0;
 778 }
 779
 780 /* Return protocol version */
 781 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
 782 {
 783         return put_user(sbi->version, p);
 784 }
 785
 786 /* Return protocol sub version */
 787 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
 788 {
 789         return put_user(sbi->sub_version, p);
 790 }
 791
 792 /*
 793 * Tells the daemon whether it can umount the autofs mount.
 794 */
 795 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
 796 {
 797         int status = 0;
 798
 799         if (may_umount(mnt))
 800                 status = 1;
 801
 802         DPRINTK("returning %d", status);
 803
 804         status = put_user(status, p);
 805
 806         return status;
 807 }
 808
 809 /* Identify autofs4_dentries - this is so we can tell if there's
 810    an extra dentry refcount or not.  We only hold a refcount on the
 811    dentry if its non-negative (ie, d_inode != NULL)
 812 */
 813 int is_autofs4_dentry(struct dentry *dentry)
 814 {
 815         return dentry && dentry->d_inode &&
 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_unlocked(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,task_pgrp_nr(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 #ifdef CONFIG_COMPAT
 855         case AUTOFS_IOC_SETTIMEOUT32:
 856                 return autofs4_compat_get_set_timeout(sbi, p);
 857 #endif
 858
 859         case AUTOFS_IOC_ASKUMOUNT:
 860                 return autofs4_ask_umount(filp->f_path.mnt, p);
 861
 862         /* return a single thing to expire */
 863         case AUTOFS_IOC_EXPIRE:
 864                 return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
 865         /* same as above, but can send multiple expires through pipe */
 866         case AUTOFS_IOC_EXPIRE_MULTI:
 867                 return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);
 868
 869         default:
 870                 return -ENOSYS;
 871         }
 872 }
 873
 874 static long autofs4_root_ioctl(struct file *filp,
 875                                unsigned int cmd, unsigned long arg)
 876 {
 877         struct inode *inode = filp->f_dentry->d_inode;
 878         return autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
 879 }
 880
 881 #ifdef CONFIG_COMPAT
 882 static long autofs4_root_compat_ioctl(struct file *filp,
 883                              unsigned int cmd, unsigned long arg)
 884 {
 885         struct inode *inode = filp->f_path.dentry->d_inode;
 886         int ret;
 887
 888         if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL)
 889                 ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
 890         else
 891                 ret = autofs4_root_ioctl_unlocked(inode, filp, cmd,
 892                         (unsigned long)compat_ptr(arg));
 893
 894         return ret;
 895 }
 896 #endif