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         ino->last_used = jiffies;
  52         atomic_set(&ino->count, 0);
  53
  54         ino->sbi = sbi;
  55
  56         if (reinit && ino->free)
  57                 (ino->free)(ino);
  58
  59         memset(&ino->u, 0, sizeof(ino->u));
  60
  61         ino->free = NULL;
  62
  63         if (S_ISLNK(mode))
  64                 ino->free = ino_lnkfree;
  65
  66         return ino;
  67 }
  68
  69 void autofs4_free_ino(struct autofs_info *ino)
  70 {
  71         struct autofs_info *p_ino;
  72
  73         if (ino->dentry) {
  74                 ino->dentry->d_fsdata = NULL;
  75                 if (ino->dentry->d_inode) {
  76                         struct dentry *parent = ino->dentry->d_parent;
  77                         if (atomic_dec_and_test(&ino->count)) {
  78                                 p_ino = autofs4_dentry_ino(parent);
  79                                 if (p_ino && parent != ino->dentry)
  80                                         atomic_dec(&p_ino->count);
  81                         }
  82                         dput(ino->dentry);
  83                 }
  84                 ino->dentry = NULL;
  85         }
  86         if (ino->free)
  87                 (ino->free)(ino);
  88         kfree(ino);
  89 }
  90
  91 /*
  92  * Deal with the infamous "Busy inodes after umount ..." message.
  93  *
  94  * Clean up the dentry tree. This happens with autofs if the user
  95  * space program goes away due to a SIGKILL, SIGSEGV etc.
  96  */
  97 static void autofs4_force_release(struct autofs_sb_info *sbi)
  98 {
  99         struct dentry *this_parent = sbi->root;
 100         struct list_head *next;
 101
 102         spin_lock(&dcache_lock);
 103 repeat:
 104         next = this_parent->d_subdirs.next;
 105 resume:
 106         while (next != &this_parent->d_subdirs) {
 107                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 108
 109                 /* Negative dentry - don`t care */
 110                 if (!simple_positive(dentry)) {
 111                         next = next->next;
 112                         continue;
 113                 }
 114
 115                 if (!list_empty(&dentry->d_subdirs)) {
 116                         this_parent = dentry;
 117                         goto repeat;
 118                 }
 119
 120                 next = next->next;
 121                 spin_unlock(&dcache_lock);
 122
 123                 DPRINTK("dentry %p %.*s",
 124                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 125
 126                 dput(dentry);
 127                 spin_lock(&dcache_lock);
 128         }
 129
 130         if (this_parent != sbi->root) {
 131                 struct dentry *dentry = this_parent;
 132
 133                 next = this_parent->d_u.d_child.next;
 134                 this_parent = this_parent->d_parent;
 135                 spin_unlock(&dcache_lock);
 136                 DPRINTK("parent dentry %p %.*s",
 137                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 138                 dput(dentry);
 139                 spin_lock(&dcache_lock);
 140                 goto resume;
 141         }
 142         spin_unlock(&dcache_lock);
 143
 144         dput(sbi->root);
 145         sbi->root = NULL;
 146         shrink_dcache_sb(sbi->sb);
 147
 148         return;
 149 }
 150
 151 static void autofs4_put_super(struct super_block *sb)
 152 {
 153         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 154
 155         sb->s_fs_info = NULL;
 156
 157         if ( !sbi->catatonic )
 158                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
 159
 160         /* Clean up and release dangling references */
 161         autofs4_force_release(sbi);
 162
 163         kfree(sbi);
 164
 165         DPRINTK("shutting down");
 166 }
 167
 168 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 169 {
 170         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 171
 172         if (!sbi)
 173                 return 0;
 174
 175         seq_printf(m, ",fd=%d", sbi->pipefd);
 176         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 177         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 178         seq_printf(m, ",minproto=%d", sbi->min_proto);
 179         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 180
 181         if (sbi->type & AUTOFS_TYPE_OFFSET)
 182                 seq_printf(m, ",offset");
 183         else if (sbi->type & AUTOFS_TYPE_DIRECT)
 184                 seq_printf(m, ",direct");
 185         else
 186                 seq_printf(m, ",indirect");
 187
 188         return 0;
 189 }
 190
 191 static struct super_operations autofs4_sops = {
 192         .put_super      = autofs4_put_super,
 193         .statfs         = simple_statfs,
 194         .show_options   = autofs4_show_options,
 195 };
 196
 197 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 198         Opt_indirect, Opt_direct, Opt_offset};
 199
 200 static match_table_t tokens = {
 201         {Opt_fd, "fd=%u"},
 202         {Opt_uid, "uid=%u"},
 203         {Opt_gid, "gid=%u"},
 204         {Opt_pgrp, "pgrp=%u"},
 205         {Opt_minproto, "minproto=%u"},
 206         {Opt_maxproto, "maxproto=%u"},
 207         {Opt_indirect, "indirect"},
 208         {Opt_direct, "direct"},
 209         {Opt_offset, "offset"},
 210         {Opt_err, NULL}
 211 };
 212
 213 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 214                          pid_t *pgrp, unsigned int *type,
 215                          int *minproto, int *maxproto)
 216 {
 217         char *p;
 218         substring_t args[MAX_OPT_ARGS];
 219         int option;
 220
 221         *uid = current->uid;
 222         *gid = current->gid;
 223         *pgrp = process_group(current);
 224
 225         *minproto = AUTOFS_MIN_PROTO_VERSION;
 226         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 227
 228         *pipefd = -1;
 229
 230         if (!options)
 231                 return 1;
 232
 233         while ((p = strsep(&options, ",")) != NULL) {
 234                 int token;
 235                 if (!*p)
 236                         continue;
 237
 238                 token = match_token(p, tokens, args);
 239                 switch (token) {
 240                 case Opt_fd:
 241                         if (match_int(args, pipefd))
 242                                 return 1;
 243                         break;
 244                 case Opt_uid:
 245                         if (match_int(args, &option))
 246                                 return 1;
 247                         *uid = option;
 248                         break;
 249                 case Opt_gid:
 250                         if (match_int(args, &option))
 251                                 return 1;
 252                         *gid = option;
 253                         break;
 254                 case Opt_pgrp:
 255                         if (match_int(args, &option))
 256                                 return 1;
 257                         *pgrp = option;
 258                         break;
 259                 case Opt_minproto:
 260                         if (match_int(args, &option))
 261                                 return 1;
 262                         *minproto = option;
 263                         break;
 264                 case Opt_maxproto:
 265                         if (match_int(args, &option))
 266                                 return 1;
 267                         *maxproto = option;
 268                         break;
 269                 case Opt_indirect:
 270                         *type = AUTOFS_TYPE_INDIRECT;
 271                         break;
 272                 case Opt_direct:
 273                         *type = AUTOFS_TYPE_DIRECT;
 274                         break;
 275                 case Opt_offset:
 276                         *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
 277                         break;
 278                 default:
 279                         return 1;
 280                 }
 281         }
 282         return (*pipefd < 0);
 283 }
 284
 285 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 286 {
 287         struct autofs_info *ino;
 288
 289         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 290         if (!ino)
 291                 return NULL;
 292
 293         return ino;
 294 }
 295
 296 static struct dentry_operations autofs4_sb_dentry_operations = {
 297         .d_release      = autofs4_dentry_release,
 298 };
 299
 300 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 301 {
 302         struct inode * root_inode;
 303         struct dentry * root;
 304         struct file * pipe;
 305         int pipefd;
 306         struct autofs_sb_info *sbi;
 307         struct autofs_info *ino;
 308
 309         sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
 310         if ( !sbi )
 311                 goto fail_unlock;
 312         DPRINTK("starting up, sbi = %p",sbi);
 313
 314         memset(sbi, 0, sizeof(*sbi));
 315
 316         s->s_fs_info = sbi;
 317         sbi->magic = AUTOFS_SBI_MAGIC;
 318         sbi->root = NULL;
 319         sbi->pipefd = -1;
 320         sbi->catatonic = 0;
 321         sbi->exp_timeout = 0;
 322         sbi->oz_pgrp = process_group(current);
 323         sbi->sb = s;
 324         sbi->version = 0;
 325         sbi->sub_version = 0;
 326         sbi->type = 0;
 327         sbi->min_proto = 0;
 328         sbi->max_proto = 0;
 329         mutex_init(&sbi->wq_mutex);
 330         spin_lock_init(&sbi->fs_lock);
 331         sbi->queues = NULL;
 332         s->s_blocksize = 1024;
 333         s->s_blocksize_bits = 10;
 334         s->s_magic = AUTOFS_SUPER_MAGIC;
 335         s->s_op = &autofs4_sops;
 336         s->s_time_gran = 1;
 337
 338         /*
 339          * Get the root inode and dentry, but defer checking for errors.
 340          */
 341         ino = autofs4_mkroot(sbi);
 342         if (!ino)
 343                 goto fail_free;
 344         root_inode = autofs4_get_inode(s, ino);
 345         if (!root_inode)
 346                 goto fail_ino;
 347
 348         root = d_alloc_root(root_inode);
 349         if (!root)
 350                 goto fail_iput;
 351         pipe = NULL;
 352
 353         root->d_op = &autofs4_sb_dentry_operations;
 354         root->d_fsdata = ino;
 355
 356         /* Can this call block? */
 357         if (parse_options(data, &pipefd,
 358                           &root_inode->i_uid, &root_inode->i_gid,
 359                           &sbi->oz_pgrp, &sbi->type,
 360                           &sbi->min_proto, &sbi->max_proto)) {
 361                 printk("autofs: called with bogus options\n");
 362                 goto fail_dput;
 363         }
 364
 365         root_inode->i_fop = &autofs4_root_operations;
 366         root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
 367                         &autofs4_direct_root_inode_operations :
 368                         &autofs4_indirect_root_inode_operations;
 369
 370         /* Couldn't this be tested earlier? */
 371         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 372             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 373                 printk("autofs: kernel does not match daemon version "
 374                        "daemon (%d, %d) kernel (%d, %d)\n",
 375                         sbi->min_proto, sbi->max_proto,
 376                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 377                 goto fail_dput;
 378         }
 379
 380         /* Establish highest kernel protocol version */
 381         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 382                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 383         else
 384                 sbi->version = sbi->max_proto;
 385         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 386
 387         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 388         pipe = fget(pipefd);
 389
 390         if ( !pipe ) {
 391                 printk("autofs: could not open pipe file descriptor\n");
 392                 goto fail_dput;
 393         }
 394         if ( !pipe->f_op || !pipe->f_op->write )
 395                 goto fail_fput;
 396         sbi->pipe = pipe;
 397         sbi->pipefd = pipefd;
 398
 399         /*
 400          * Take a reference to the root dentry so we get a chance to
 401          * clean up the dentry tree on umount.
 402          * See autofs4_force_release.
 403          */
 404         sbi->root = dget(root);
 405
 406         /*
 407          * Success! Install the root dentry now to indicate completion.
 408          */
 409         s->s_root = root;
 410         return 0;
 411
 412         /*
 413          * Failure ... clean up.
 414          */
 415 fail_fput:
 416         printk("autofs: pipe file descriptor does not contain proper ops\n");
 417         fput(pipe);
 418         /* fall through */
 419 fail_dput:
 420         dput(root);
 421         goto fail_free;
 422 fail_iput:
 423         printk("autofs: get root dentry failed\n");
 424         iput(root_inode);
 425 fail_ino:
 426         kfree(ino);
 427 fail_free:
 428         kfree(sbi);
 429 fail_unlock:
 430         return -EINVAL;
 431 }
 432
 433 struct inode *autofs4_get_inode(struct super_block *sb,
 434                                 struct autofs_info *inf)
 435 {
 436         struct inode *inode = new_inode(sb);
 437
 438         if (inode == NULL)
 439                 return NULL;
 440
 441         inf->inode = inode;
 442         inode->i_mode = inf->mode;
 443         if (sb->s_root) {
 444                 inode->i_uid = sb->s_root->d_inode->i_uid;
 445                 inode->i_gid = sb->s_root->d_inode->i_gid;
 446         } else {
 447                 inode->i_uid = 0;
 448                 inode->i_gid = 0;
 449         }
 450         inode->i_blocks = 0;
 451         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 452
 453         if (S_ISDIR(inf->mode)) {
 454                 inode->i_nlink = 2;
 455                 inode->i_op = &autofs4_dir_inode_operations;
 456                 inode->i_fop = &autofs4_dir_operations;
 457         } else if (S_ISLNK(inf->mode)) {
 458                 inode->i_size = inf->size;
 459                 inode->i_op = &autofs4_symlink_inode_operations;
 460         }
 461
 462         return inode;
 463 }