fs/autofs4/inode.c

   1 /* -*- c -*- --------------------------------------------------------------- *
   2  *
   3  * linux/fs/autofs/inode.c
   4  *
   5  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   6  *  Copyright 2005-2006 Ian Kent <raven@themaw.net>
   7  *
   8  * This file is part of the Linux kernel and is made available under
   9  * the terms of the GNU General Public License, version 2, or at your
  10  * option, any later version, incorporated herein by reference.
  11  *
  12  * ------------------------------------------------------------------------- */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/file.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/parser.h>
  20 #include <linux/bitops.h>
  21 #include <linux/smp_lock.h>
  22 #include <linux/magic.h>
  23 #include "autofs_i.h"
  24 #include <linux/module.h>
  25
  26 static void ino_lnkfree(struct autofs_info *ino)
  27 {
  28         kfree(ino->u.symlink);
  29         ino->u.symlink = NULL;
  30 }
  31
  32 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
  33                                      struct autofs_sb_info *sbi, mode_t mode)
  34 {
  35         int reinit = 1;
  36
  37         if (ino == NULL) {
  38                 reinit = 0;
  39                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
  40         }
  41
  42         if (ino == NULL)
  43                 return NULL;
  44
  45         ino->flags = 0;
  46         ino->mode = mode;
  47         ino->inode = NULL;
  48         ino->dentry = NULL;
  49         ino->size = 0;
  50
  51         INIT_LIST_HEAD(&ino->rehash);
  52
  53         ino->last_used = jiffies;
  54         atomic_set(&ino->count, 0);
  55
  56         ino->sbi = sbi;
  57
  58         if (reinit && ino->free)
  59                 (ino->free)(ino);
  60
  61         memset(&ino->u, 0, sizeof(ino->u));
  62
  63         ino->free = NULL;
  64
  65         if (S_ISLNK(mode))
  66                 ino->free = ino_lnkfree;
  67
  68         return ino;
  69 }
  70
  71 void autofs4_free_ino(struct autofs_info *ino)
  72 {
  73         struct autofs_info *p_ino;
  74
  75         if (ino->dentry) {
  76                 ino->dentry->d_fsdata = NULL;
  77                 if (ino->dentry->d_inode) {
  78                         struct dentry *parent = ino->dentry->d_parent;
  79                         if (atomic_dec_and_test(&ino->count)) {
  80                                 p_ino = autofs4_dentry_ino(parent);
  81                                 if (p_ino && parent != ino->dentry)
  82                                         atomic_dec(&p_ino->count);
  83                         }
  84                         dput(ino->dentry);
  85                 }
  86                 ino->dentry = NULL;
  87         }
  88         if (ino->free)
  89                 (ino->free)(ino);
  90         kfree(ino);
  91 }
  92
  93 /*
  94  * Deal with the infamous "Busy inodes after umount ..." message.
  95  *
  96  * Clean up the dentry tree. This happens with autofs if the user
  97  * space program goes away due to a SIGKILL, SIGSEGV etc.
  98  */
  99 static void autofs4_force_release(struct autofs_sb_info *sbi)
 100 {
 101         struct dentry *this_parent = sbi->sb->s_root;
 102         struct list_head *next;
 103
 104         if (!sbi->sb->s_root)
 105                 return;
 106
 107         spin_lock(&dcache_lock);
 108 repeat:
 109         next = this_parent->d_subdirs.next;
 110 resume:
 111         while (next != &this_parent->d_subdirs) {
 112                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 113
 114                 /* Negative dentry - don`t care */
 115                 if (!simple_positive(dentry)) {
 116                         next = next->next;
 117                         continue;
 118                 }
 119
 120                 if (!list_empty(&dentry->d_subdirs)) {
 121                         this_parent = dentry;
 122                         goto repeat;
 123                 }
 124
 125                 next = next->next;
 126                 spin_unlock(&dcache_lock);
 127
 128                 DPRINTK("dentry %p %.*s",
 129                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 130
 131                 dput(dentry);
 132                 spin_lock(&dcache_lock);
 133         }
 134
 135         if (this_parent != sbi->sb->s_root) {
 136                 struct dentry *dentry = this_parent;
 137
 138                 next = this_parent->d_u.d_child.next;
 139                 this_parent = this_parent->d_parent;
 140                 spin_unlock(&dcache_lock);
 141                 DPRINTK("parent dentry %p %.*s",
 142                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 143                 dput(dentry);
 144                 spin_lock(&dcache_lock);
 145                 goto resume;
 146         }
 147         spin_unlock(&dcache_lock);
 148 }
 149
 150 void autofs4_kill_sb(struct super_block *sb)
 151 {
 152         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 153
 154         /*
 155          * In the event of a failure in get_sb_nodev the superblock
 156          * info is not present so nothing else has been setup, so
 157          * just call kill_anon_super when we are called from
 158          * deactivate_super.
 159          */
 160         if (!sbi)
 161                 goto out_kill_sb;
 162
 163         if (!sbi->catatonic)
 164                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
 165
 166         /* Clean up and release dangling references */
 167         autofs4_force_release(sbi);
 168
 169         sb->s_fs_info = NULL;
 170         kfree(sbi);
 171
 172 out_kill_sb:
 173         DPRINTK("shutting down");
 174         kill_anon_super(sb);
 175 }
 176
 177 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 178 {
 179         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 180
 181         if (!sbi)
 182                 return 0;
 183
 184         seq_printf(m, ",fd=%d", sbi->pipefd);
 185         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 186         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 187         seq_printf(m, ",minproto=%d", sbi->min_proto);
 188         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 189
 190         if (sbi->type & AUTOFS_TYPE_OFFSET)
 191                 seq_printf(m, ",offset");
 192         else if (sbi->type & AUTOFS_TYPE_DIRECT)
 193                 seq_printf(m, ",direct");
 194         else
 195                 seq_printf(m, ",indirect");
 196
 197         return 0;
 198 }
 199
 200 static const struct super_operations autofs4_sops = {
 201         .statfs         = simple_statfs,
 202         .show_options   = autofs4_show_options,
 203 };
 204
 205 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 206         Opt_indirect, Opt_direct, Opt_offset};
 207
 208 static match_table_t tokens = {
 209         {Opt_fd, "fd=%u"},
 210         {Opt_uid, "uid=%u"},
 211         {Opt_gid, "gid=%u"},
 212         {Opt_pgrp, "pgrp=%u"},
 213         {Opt_minproto, "minproto=%u"},
 214         {Opt_maxproto, "maxproto=%u"},
 215         {Opt_indirect, "indirect"},
 216         {Opt_direct, "direct"},
 217         {Opt_offset, "offset"},
 218         {Opt_err, NULL}
 219 };
 220
 221 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 222                          pid_t *pgrp, unsigned int *type,
 223                          int *minproto, int *maxproto)
 224 {
 225         char *p;
 226         substring_t args[MAX_OPT_ARGS];
 227         int option;
 228
 229         *uid = current->uid;
 230         *gid = current->gid;
 231         *pgrp = process_group(current);
 232
 233         *minproto = AUTOFS_MIN_PROTO_VERSION;
 234         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 235
 236         *pipefd = -1;
 237
 238         if (!options)
 239                 return 1;
 240
 241         while ((p = strsep(&options, ",")) != NULL) {
 242                 int token;
 243                 if (!*p)
 244                         continue;
 245
 246                 token = match_token(p, tokens, args);
 247                 switch (token) {
 248                 case Opt_fd:
 249                         if (match_int(args, pipefd))
 250                                 return 1;
 251                         break;
 252                 case Opt_uid:
 253                         if (match_int(args, &option))
 254                                 return 1;
 255                         *uid = option;
 256                         break;
 257                 case Opt_gid:
 258                         if (match_int(args, &option))
 259                                 return 1;
 260                         *gid = option;
 261                         break;
 262                 case Opt_pgrp:
 263                         if (match_int(args, &option))
 264                                 return 1;
 265                         *pgrp = option;
 266                         break;
 267                 case Opt_minproto:
 268                         if (match_int(args, &option))
 269                                 return 1;
 270                         *minproto = option;
 271                         break;
 272                 case Opt_maxproto:
 273                         if (match_int(args, &option))
 274                                 return 1;
 275                         *maxproto = option;
 276                         break;
 277                 case Opt_indirect:
 278                         *type = AUTOFS_TYPE_INDIRECT;
 279                         break;
 280                 case Opt_direct:
 281                         *type = AUTOFS_TYPE_DIRECT;
 282                         break;
 283                 case Opt_offset:
 284                         *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
 285                         break;
 286                 default:
 287                         return 1;
 288                 }
 289         }
 290         return (*pipefd < 0);
 291 }
 292
 293 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 294 {
 295         struct autofs_info *ino;
 296
 297         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 298         if (!ino)
 299                 return NULL;
 300
 301         return ino;
 302 }
 303
 304 static struct dentry_operations autofs4_sb_dentry_operations = {
 305         .d_release      = autofs4_dentry_release,
 306 };
 307
 308 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 309 {
 310         struct inode * root_inode;
 311         struct dentry * root;
 312         struct file * pipe;
 313         int pipefd;
 314         struct autofs_sb_info *sbi;
 315         struct autofs_info *ino;
 316
 317         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 318         if ( !sbi )
 319                 goto fail_unlock;
 320         DPRINTK("starting up, sbi = %p",sbi);
 321
 322         memset(sbi, 0, sizeof(*sbi));
 323
 324         s->s_fs_info = sbi;
 325         sbi->magic = AUTOFS_SBI_MAGIC;
 326         sbi->pipefd = -1;
 327         sbi->pipe = NULL;
 328         sbi->catatonic = 1;
 329         sbi->exp_timeout = 0;
 330         sbi->oz_pgrp = process_group(current);
 331         sbi->sb = s;
 332         sbi->version = 0;
 333         sbi->sub_version = 0;
 334         sbi->type = 0;
 335         sbi->min_proto = 0;
 336         sbi->max_proto = 0;
 337         mutex_init(&sbi->wq_mutex);
 338         spin_lock_init(&sbi->fs_lock);
 339         sbi->queues = NULL;
 340         spin_lock_init(&sbi->rehash_lock);
 341         INIT_LIST_HEAD(&sbi->rehash_list);
 342         s->s_blocksize = 1024;
 343         s->s_blocksize_bits = 10;
 344         s->s_magic = AUTOFS_SUPER_MAGIC;
 345         s->s_op = &autofs4_sops;
 346         s->s_time_gran = 1;
 347
 348         /*
 349          * Get the root inode and dentry, but defer checking for errors.
 350          */
 351         ino = autofs4_mkroot(sbi);
 352         if (!ino)
 353                 goto fail_free;
 354         root_inode = autofs4_get_inode(s, ino);
 355         if (!root_inode)
 356                 goto fail_ino;
 357
 358         root = d_alloc_root(root_inode);
 359         if (!root)
 360                 goto fail_iput;
 361         pipe = NULL;
 362
 363         root->d_op = &autofs4_sb_dentry_operations;
 364         root->d_fsdata = ino;
 365
 366         /* Can this call block? */
 367         if (parse_options(data, &pipefd,
 368                           &root_inode->i_uid, &root_inode->i_gid,
 369                           &sbi->oz_pgrp, &sbi->type,
 370                           &sbi->min_proto, &sbi->max_proto)) {
 371                 printk("autofs: called with bogus options\n");
 372                 goto fail_dput;
 373         }
 374
 375         root_inode->i_fop = &autofs4_root_operations;
 376         root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
 377                         &autofs4_direct_root_inode_operations :
 378                         &autofs4_indirect_root_inode_operations;
 379
 380         /* Couldn't this be tested earlier? */
 381         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 382             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 383                 printk("autofs: kernel does not match daemon version "
 384                        "daemon (%d, %d) kernel (%d, %d)\n",
 385                         sbi->min_proto, sbi->max_proto,
 386                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 387                 goto fail_dput;
 388         }
 389
 390         /* Establish highest kernel protocol version */
 391         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 392                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 393         else
 394                 sbi->version = sbi->max_proto;
 395         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 396
 397         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 398         pipe = fget(pipefd);
 399
 400         if ( !pipe ) {
 401                 printk("autofs: could not open pipe file descriptor\n");
 402                 goto fail_dput;
 403         }
 404         if ( !pipe->f_op || !pipe->f_op->write )
 405                 goto fail_fput;
 406         sbi->pipe = pipe;
 407         sbi->pipefd = pipefd;
 408         sbi->catatonic = 0;
 409
 410         /*
 411          * Success! Install the root dentry now to indicate completion.
 412          */
 413         s->s_root = root;
 414         return 0;
 415
 416         /*
 417          * Failure ... clean up.
 418          */
 419 fail_fput:
 420         printk("autofs: pipe file descriptor does not contain proper ops\n");
 421         fput(pipe);
 422         /* fall through */
 423 fail_dput:
 424         dput(root);
 425         goto fail_free;
 426 fail_iput:
 427         printk("autofs: get root dentry failed\n");
 428         iput(root_inode);
 429 fail_ino:
 430         kfree(ino);
 431 fail_free:
 432         kfree(sbi);
 433         s->s_fs_info = NULL;
 434 fail_unlock:
 435         return -EINVAL;
 436 }
 437
 438 struct inode *autofs4_get_inode(struct super_block *sb,
 439                                 struct autofs_info *inf)
 440 {
 441         struct inode *inode = new_inode(sb);
 442
 443         if (inode == NULL)
 444                 return NULL;
 445
 446         inf->inode = inode;
 447         inode->i_mode = inf->mode;
 448         if (sb->s_root) {
 449                 inode->i_uid = sb->s_root->d_inode->i_uid;
 450                 inode->i_gid = sb->s_root->d_inode->i_gid;
 451         } else {
 452                 inode->i_uid = 0;
 453                 inode->i_gid = 0;
 454         }
 455         inode->i_blocks = 0;
 456         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 457
 458         if (S_ISDIR(inf->mode)) {
 459                 inode->i_nlink = 2;
 460                 inode->i_op = &autofs4_dir_inode_operations;
 461                 inode->i_fop = &autofs4_dir_operations;
 462         } else if (S_ISLNK(inf->mode)) {
 463                 inode->i_size = inf->size;
 464                 inode->i_op = &autofs4_symlink_inode_operations;
 465         }
 466
 467         return inode;
 468 }