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/magic.h>
  22 #include "autofs_i.h"
  23 #include <linux/module.h>
  24
  25 static void ino_lnkfree(struct autofs_info *ino)
  26 {
  27         kfree(ino->u.symlink);
  28         ino->u.symlink = NULL;
  29 }
  30
  31 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
  32                                      struct autofs_sb_info *sbi, mode_t mode)
  33 {
  34         int reinit = 1;
  35
  36         if (ino == NULL) {
  37                 reinit = 0;
  38                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
  39         }
  40
  41         if (ino == NULL)
  42                 return NULL;
  43
  44         ino->flags = 0;
  45         ino->mode = mode;
  46         ino->inode = NULL;
  47         ino->dentry = NULL;
  48         ino->size = 0;
  49
  50         INIT_LIST_HEAD(&ino->rehash);
  51
  52         ino->last_used = jiffies;
  53         atomic_set(&ino->count, 0);
  54
  55         ino->sbi = sbi;
  56
  57         if (reinit && ino->free)
  58                 (ino->free)(ino);
  59
  60         memset(&ino->u, 0, sizeof(ino->u));
  61
  62         ino->free = NULL;
  63
  64         if (S_ISLNK(mode))
  65                 ino->free = ino_lnkfree;
  66
  67         return ino;
  68 }
  69
  70 void autofs4_free_ino(struct autofs_info *ino)
  71 {
  72         struct autofs_info *p_ino;
  73
  74         if (ino->dentry) {
  75                 ino->dentry->d_fsdata = NULL;
  76                 if (ino->dentry->d_inode) {
  77                         struct dentry *parent = ino->dentry->d_parent;
  78                         if (atomic_dec_and_test(&ino->count)) {
  79                                 p_ino = autofs4_dentry_ino(parent);
  80                                 if (p_ino && parent != ino->dentry)
  81                                         atomic_dec(&p_ino->count);
  82                         }
  83                         dput(ino->dentry);
  84                 }
  85                 ino->dentry = NULL;
  86         }
  87         if (ino->free)
  88                 (ino->free)(ino);
  89         kfree(ino);
  90 }
  91
  92 /*
  93  * Deal with the infamous "Busy inodes after umount ..." message.
  94  *
  95  * Clean up the dentry tree. This happens with autofs if the user
  96  * space program goes away due to a SIGKILL, SIGSEGV etc.
  97  */
  98 static void autofs4_force_release(struct autofs_sb_info *sbi)
  99 {
 100         struct dentry *this_parent = sbi->sb->s_root;
 101         struct list_head *next;
 102
 103         if (!sbi->sb->s_root)
 104                 return;
 105
 106         spin_lock(&dcache_lock);
 107 repeat:
 108         next = this_parent->d_subdirs.next;
 109 resume:
 110         while (next != &this_parent->d_subdirs) {
 111                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 112
 113                 /* Negative dentry - don`t care */
 114                 if (!simple_positive(dentry)) {
 115                         next = next->next;
 116                         continue;
 117                 }
 118
 119                 if (!list_empty(&dentry->d_subdirs)) {
 120                         this_parent = dentry;
 121                         goto repeat;
 122                 }
 123
 124                 next = next->next;
 125                 spin_unlock(&dcache_lock);
 126
 127                 DPRINTK("dentry %p %.*s",
 128                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 129
 130                 dput(dentry);
 131                 spin_lock(&dcache_lock);
 132         }
 133
 134         if (this_parent != sbi->sb->s_root) {
 135                 struct dentry *dentry = this_parent;
 136
 137                 next = this_parent->d_u.d_child.next;
 138                 this_parent = this_parent->d_parent;
 139                 spin_unlock(&dcache_lock);
 140                 DPRINTK("parent dentry %p %.*s",
 141                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 142                 dput(dentry);
 143                 spin_lock(&dcache_lock);
 144                 goto resume;
 145         }
 146         spin_unlock(&dcache_lock);
 147 }
 148
 149 void autofs4_kill_sb(struct super_block *sb)
 150 {
 151         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 152
 153         /*
 154          * In the event of a failure in get_sb_nodev the superblock
 155          * info is not present so nothing else has been setup, so
 156          * just call kill_anon_super when we are called from
 157          * deactivate_super.
 158          */
 159         if (!sbi)
 160                 goto out_kill_sb;
 161
 162         if (!sbi->catatonic)
 163                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
 164
 165         /* Clean up and release dangling references */
 166         autofs4_force_release(sbi);
 167
 168         sb->s_fs_info = NULL;
 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, int *minproto, int *maxproto)
 222 {
 223         char *p;
 224         substring_t args[MAX_OPT_ARGS];
 225         int option;
 226
 227         *uid = current->uid;
 228         *gid = current->gid;
 229         *pgrp = process_group(current);
 230
 231         *minproto = AUTOFS_MIN_PROTO_VERSION;
 232         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 233
 234         *pipefd = -1;
 235
 236         if (!options)
 237                 return 1;
 238
 239         while ((p = strsep(&options, ",")) != NULL) {
 240                 int token;
 241                 if (!*p)
 242                         continue;
 243
 244                 token = match_token(p, tokens, args);
 245                 switch (token) {
 246                 case Opt_fd:
 247                         if (match_int(args, pipefd))
 248                                 return 1;
 249                         break;
 250                 case Opt_uid:
 251                         if (match_int(args, &option))
 252                                 return 1;
 253                         *uid = option;
 254                         break;
 255                 case Opt_gid:
 256                         if (match_int(args, &option))
 257                                 return 1;
 258                         *gid = option;
 259                         break;
 260                 case Opt_pgrp:
 261                         if (match_int(args, &option))
 262                                 return 1;
 263                         *pgrp = option;
 264                         break;
 265                 case Opt_minproto:
 266                         if (match_int(args, &option))
 267                                 return 1;
 268                         *minproto = option;
 269                         break;
 270                 case Opt_maxproto:
 271                         if (match_int(args, &option))
 272                                 return 1;
 273                         *maxproto = option;
 274                         break;
 275                 case Opt_indirect:
 276                         *type = AUTOFS_TYPE_INDIRECT;
 277                         break;
 278                 case Opt_direct:
 279                         *type = AUTOFS_TYPE_DIRECT;
 280                         break;
 281                 case Opt_offset:
 282                         *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
 283                         break;
 284                 default:
 285                         return 1;
 286                 }
 287         }
 288         return (*pipefd < 0);
 289 }
 290
 291 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 292 {
 293         struct autofs_info *ino;
 294
 295         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 296         if (!ino)
 297                 return NULL;
 298
 299         return ino;
 300 }
 301
 302 static struct dentry_operations autofs4_sb_dentry_operations = {
 303         .d_release      = autofs4_dentry_release,
 304 };
 305
 306 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 307 {
 308         struct inode * root_inode;
 309         struct dentry * root;
 310         struct file * pipe;
 311         int pipefd;
 312         struct autofs_sb_info *sbi;
 313         struct autofs_info *ino;
 314
 315         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 316         if (!sbi)
 317                 goto fail_unlock;
 318         DPRINTK("starting up, sbi = %p",sbi);
 319
 320         s->s_fs_info = sbi;
 321         sbi->magic = AUTOFS_SBI_MAGIC;
 322         sbi->pipefd = -1;
 323         sbi->pipe = NULL;
 324         sbi->catatonic = 1;
 325         sbi->exp_timeout = 0;
 326         sbi->oz_pgrp = process_group(current);
 327         sbi->sb = s;
 328         sbi->version = 0;
 329         sbi->sub_version = 0;
 330         sbi->type = 0;
 331         sbi->min_proto = 0;
 332         sbi->max_proto = 0;
 333         mutex_init(&sbi->wq_mutex);
 334         spin_lock_init(&sbi->fs_lock);
 335         sbi->queues = NULL;
 336         spin_lock_init(&sbi->rehash_lock);
 337         INIT_LIST_HEAD(&sbi->rehash_list);
 338         s->s_blocksize = 1024;
 339         s->s_blocksize_bits = 10;
 340         s->s_magic = AUTOFS_SUPER_MAGIC;
 341         s->s_op = &autofs4_sops;
 342         s->s_time_gran = 1;
 343
 344         /*
 345          * Get the root inode and dentry, but defer checking for errors.
 346          */
 347         ino = autofs4_mkroot(sbi);
 348         if (!ino)
 349                 goto fail_free;
 350         root_inode = autofs4_get_inode(s, ino);
 351         if (!root_inode)
 352                 goto fail_ino;
 353
 354         root = d_alloc_root(root_inode);
 355         if (!root)
 356                 goto fail_iput;
 357         pipe = NULL;
 358
 359         root->d_op = &autofs4_sb_dentry_operations;
 360         root->d_fsdata = ino;
 361
 362         /* Can this call block? */
 363         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 364                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 365                                 &sbi->max_proto)) {
 366                 printk("autofs: called with bogus options\n");
 367                 goto fail_dput;
 368         }
 369
 370         root_inode->i_fop = &autofs4_root_operations;
 371         root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
 372                         &autofs4_direct_root_inode_operations :
 373                         &autofs4_indirect_root_inode_operations;
 374
 375         /* Couldn't this be tested earlier? */
 376         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 377             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 378                 printk("autofs: kernel does not match daemon version "
 379                        "daemon (%d, %d) kernel (%d, %d)\n",
 380                         sbi->min_proto, sbi->max_proto,
 381                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 382                 goto fail_dput;
 383         }
 384
 385         /* Establish highest kernel protocol version */
 386         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 387                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 388         else
 389                 sbi->version = sbi->max_proto;
 390         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 391
 392         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 393         pipe = fget(pipefd);
 394
 395         if (!pipe) {
 396                 printk("autofs: could not open pipe file descriptor\n");
 397                 goto fail_dput;
 398         }
 399         if (!pipe->f_op || !pipe->f_op->write)
 400                 goto fail_fput;
 401         sbi->pipe = pipe;
 402         sbi->pipefd = pipefd;
 403         sbi->catatonic = 0;
 404
 405         /*
 406          * Success! Install the root dentry now to indicate completion.
 407          */
 408         s->s_root = root;
 409         return 0;
 410
 411         /*
 412          * Failure ... clean up.
 413          */
 414 fail_fput:
 415         printk("autofs: pipe file descriptor does not contain proper ops\n");
 416         fput(pipe);
 417         /* fall through */
 418 fail_dput:
 419         dput(root);
 420         goto fail_free;
 421 fail_iput:
 422         printk("autofs: get root dentry failed\n");
 423         iput(root_inode);
 424 fail_ino:
 425         kfree(ino);
 426 fail_free:
 427         kfree(sbi);
 428         s->s_fs_info = NULL;
 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 }