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->sb->s_root;
 100         struct list_head *next;
 101
 102         if (!sbi->sb->s_root)
 103                 return;
 104
 105         spin_lock(&dcache_lock);
 106 repeat:
 107         next = this_parent->d_subdirs.next;
 108 resume:
 109         while (next != &this_parent->d_subdirs) {
 110                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 111
 112                 /* Negative dentry - don`t care */
 113                 if (!simple_positive(dentry)) {
 114                         next = next->next;
 115                         continue;
 116                 }
 117
 118                 if (!list_empty(&dentry->d_subdirs)) {
 119                         this_parent = dentry;
 120                         goto repeat;
 121                 }
 122
 123                 next = next->next;
 124                 spin_unlock(&dcache_lock);
 125
 126                 DPRINTK("dentry %p %.*s",
 127                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 128
 129                 dput(dentry);
 130                 spin_lock(&dcache_lock);
 131         }
 132
 133         if (this_parent != sbi->sb->s_root) {
 134                 struct dentry *dentry = this_parent;
 135
 136                 next = this_parent->d_u.d_child.next;
 137                 this_parent = this_parent->d_parent;
 138                 spin_unlock(&dcache_lock);
 139                 DPRINTK("parent dentry %p %.*s",
 140                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 141                 dput(dentry);
 142                 spin_lock(&dcache_lock);
 143                 goto resume;
 144         }
 145         spin_unlock(&dcache_lock);
 146 }
 147
 148 void autofs4_kill_sb(struct super_block *sb)
 149 {
 150         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 151
 152         /*
 153          * In the event of a failure in get_sb_nodev the superblock
 154          * info is not present so nothing else has been setup, so
 155          * just call kill_anon_super when we are called from
 156          * deactivate_super.
 157          */
 158         if (!sbi)
 159                 goto out_kill_sb;
 160
 161         sb->s_fs_info = NULL;
 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         kfree(sbi);
 170
 171 out_kill_sb:
 172         DPRINTK("shutting down");
 173         kill_anon_super(sb);
 174 }
 175
 176 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 177 {
 178         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 179
 180         if (!sbi)
 181                 return 0;
 182
 183         seq_printf(m, ",fd=%d", sbi->pipefd);
 184         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 185         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 186         seq_printf(m, ",minproto=%d", sbi->min_proto);
 187         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 188
 189         if (sbi->type & AUTOFS_TYPE_OFFSET)
 190                 seq_printf(m, ",offset");
 191         else if (sbi->type & AUTOFS_TYPE_DIRECT)
 192                 seq_printf(m, ",direct");
 193         else
 194                 seq_printf(m, ",indirect");
 195
 196         return 0;
 197 }
 198
 199 static const struct super_operations autofs4_sops = {
 200         .statfs         = simple_statfs,
 201         .show_options   = autofs4_show_options,
 202 };
 203
 204 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 205         Opt_indirect, Opt_direct, Opt_offset};
 206
 207 static match_table_t tokens = {
 208         {Opt_fd, "fd=%u"},
 209         {Opt_uid, "uid=%u"},
 210         {Opt_gid, "gid=%u"},
 211         {Opt_pgrp, "pgrp=%u"},
 212         {Opt_minproto, "minproto=%u"},
 213         {Opt_maxproto, "maxproto=%u"},
 214         {Opt_indirect, "indirect"},
 215         {Opt_direct, "direct"},
 216         {Opt_offset, "offset"},
 217         {Opt_err, NULL}
 218 };
 219
 220 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 221                          pid_t *pgrp, unsigned int *type,
 222                          int *minproto, int *maxproto)
 223 {
 224         char *p;
 225         substring_t args[MAX_OPT_ARGS];
 226         int option;
 227
 228         *uid = current->uid;
 229         *gid = current->gid;
 230         *pgrp = process_group(current);
 231
 232         *minproto = AUTOFS_MIN_PROTO_VERSION;
 233         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 234
 235         *pipefd = -1;
 236
 237         if (!options)
 238                 return 1;
 239
 240         while ((p = strsep(&options, ",")) != NULL) {
 241                 int token;
 242                 if (!*p)
 243                         continue;
 244
 245                 token = match_token(p, tokens, args);
 246                 switch (token) {
 247                 case Opt_fd:
 248                         if (match_int(args, pipefd))
 249                                 return 1;
 250                         break;
 251                 case Opt_uid:
 252                         if (match_int(args, &option))
 253                                 return 1;
 254                         *uid = option;
 255                         break;
 256                 case Opt_gid:
 257                         if (match_int(args, &option))
 258                                 return 1;
 259                         *gid = option;
 260                         break;
 261                 case Opt_pgrp:
 262                         if (match_int(args, &option))
 263                                 return 1;
 264                         *pgrp = option;
 265                         break;
 266                 case Opt_minproto:
 267                         if (match_int(args, &option))
 268                                 return 1;
 269                         *minproto = option;
 270                         break;
 271                 case Opt_maxproto:
 272                         if (match_int(args, &option))
 273                                 return 1;
 274                         *maxproto = option;
 275                         break;
 276                 case Opt_indirect:
 277                         *type = AUTOFS_TYPE_INDIRECT;
 278                         break;
 279                 case Opt_direct:
 280                         *type = AUTOFS_TYPE_DIRECT;
 281                         break;
 282                 case Opt_offset:
 283                         *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
 284                         break;
 285                 default:
 286                         return 1;
 287                 }
 288         }
 289         return (*pipefd < 0);
 290 }
 291
 292 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 293 {
 294         struct autofs_info *ino;
 295
 296         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 297         if (!ino)
 298                 return NULL;
 299
 300         return ino;
 301 }
 302
 303 static struct dentry_operations autofs4_sb_dentry_operations = {
 304         .d_release      = autofs4_dentry_release,
 305 };
 306
 307 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 308 {
 309         struct inode * root_inode;
 310         struct dentry * root;
 311         struct file * pipe;
 312         int pipefd;
 313         struct autofs_sb_info *sbi;
 314         struct autofs_info *ino;
 315
 316         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 317         if ( !sbi )
 318                 goto fail_unlock;
 319         DPRINTK("starting up, sbi = %p",sbi);
 320
 321         memset(sbi, 0, sizeof(*sbi));
 322
 323         s->s_fs_info = sbi;
 324         sbi->magic = AUTOFS_SBI_MAGIC;
 325         sbi->pipefd = -1;
 326         sbi->pipe = NULL;
 327         sbi->catatonic = 1;
 328         sbi->exp_timeout = 0;
 329         sbi->oz_pgrp = process_group(current);
 330         sbi->sb = s;
 331         sbi->version = 0;
 332         sbi->sub_version = 0;
 333         sbi->type = 0;
 334         sbi->min_proto = 0;
 335         sbi->max_proto = 0;
 336         mutex_init(&sbi->wq_mutex);
 337         spin_lock_init(&sbi->fs_lock);
 338         sbi->queues = NULL;
 339         s->s_blocksize = 1024;
 340         s->s_blocksize_bits = 10;
 341         s->s_magic = AUTOFS_SUPER_MAGIC;
 342         s->s_op = &autofs4_sops;
 343         s->s_time_gran = 1;
 344
 345         /*
 346          * Get the root inode and dentry, but defer checking for errors.
 347          */
 348         ino = autofs4_mkroot(sbi);
 349         if (!ino)
 350                 goto fail_free;
 351         root_inode = autofs4_get_inode(s, ino);
 352         if (!root_inode)
 353                 goto fail_ino;
 354
 355         root = d_alloc_root(root_inode);
 356         if (!root)
 357                 goto fail_iput;
 358         pipe = NULL;
 359
 360         root->d_op = &autofs4_sb_dentry_operations;
 361         root->d_fsdata = ino;
 362
 363         /* Can this call block? */
 364         if (parse_options(data, &pipefd,
 365                           &root_inode->i_uid, &root_inode->i_gid,
 366                           &sbi->oz_pgrp, &sbi->type,
 367                           &sbi->min_proto, &sbi->max_proto)) {
 368                 printk("autofs: called with bogus options\n");
 369                 goto fail_dput;
 370         }
 371
 372         root_inode->i_fop = &autofs4_root_operations;
 373         root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
 374                         &autofs4_direct_root_inode_operations :
 375                         &autofs4_indirect_root_inode_operations;
 376
 377         /* Couldn't this be tested earlier? */
 378         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 379             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 380                 printk("autofs: kernel does not match daemon version "
 381                        "daemon (%d, %d) kernel (%d, %d)\n",
 382                         sbi->min_proto, sbi->max_proto,
 383                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 384                 goto fail_dput;
 385         }
 386
 387         /* Establish highest kernel protocol version */
 388         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 389                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 390         else
 391                 sbi->version = sbi->max_proto;
 392         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 393
 394         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 395         pipe = fget(pipefd);
 396
 397         if ( !pipe ) {
 398                 printk("autofs: could not open pipe file descriptor\n");
 399                 goto fail_dput;
 400         }
 401         if ( !pipe->f_op || !pipe->f_op->write )
 402                 goto fail_fput;
 403         sbi->pipe = pipe;
 404         sbi->pipefd = pipefd;
 405         sbi->catatonic = 0;
 406
 407         /*
 408          * Success! Install the root dentry now to indicate completion.
 409          */
 410         s->s_root = root;
 411         return 0;
 412
 413         /*
 414          * Failure ... clean up.
 415          */
 416 fail_fput:
 417         printk("autofs: pipe file descriptor does not contain proper ops\n");
 418         fput(pipe);
 419         /* fall through */
 420 fail_dput:
 421         dput(root);
 422         goto fail_free;
 423 fail_iput:
 424         printk("autofs: get root dentry failed\n");
 425         iput(root_inode);
 426 fail_ino:
 427         kfree(ino);
 428 fail_free:
 429         kfree(sbi);
 430         s->s_fs_info = NULL;
 431 fail_unlock:
 432         return -EINVAL;
 433 }
 434
 435 struct inode *autofs4_get_inode(struct super_block *sb,
 436                                 struct autofs_info *inf)
 437 {
 438         struct inode *inode = new_inode(sb);
 439
 440         if (inode == NULL)
 441                 return NULL;
 442
 443         inf->inode = inode;
 444         inode->i_mode = inf->mode;
 445         if (sb->s_root) {
 446                 inode->i_uid = sb->s_root->d_inode->i_uid;
 447                 inode->i_gid = sb->s_root->d_inode->i_gid;
 448         } else {
 449                 inode->i_uid = 0;
 450                 inode->i_gid = 0;
 451         }
 452         inode->i_blocks = 0;
 453         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 454
 455         if (S_ISDIR(inf->mode)) {
 456                 inode->i_nlink = 2;
 457                 inode->i_op = &autofs4_dir_inode_operations;
 458                 inode->i_fop = &autofs4_dir_operations;
 459         } else if (S_ISLNK(inf->mode)) {
 460                 inode->i_size = inf->size;
 461                 inode->i_op = &autofs4_symlink_inode_operations;
 462         }
 463
 464         return inode;
 465 }