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         if (ino->u.symlink) {
  28                 kfree(ino->u.symlink);
  29                 ino->u.symlink = NULL;
  30         }
  31 }
  32
  33 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
  34                                      struct autofs_sb_info *sbi, mode_t mode)
  35 {
  36         int reinit = 1;
  37
  38         if (ino == NULL) {
  39                 reinit = 0;
  40                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
  41         }
  42
  43         if (ino == NULL)
  44                 return NULL;
  45
  46         if (!reinit) {
  47                 ino->flags = 0;
  48                 ino->inode = NULL;
  49                 ino->dentry = NULL;
  50                 ino->size = 0;
  51                 INIT_LIST_HEAD(&ino->active);
  52                 INIT_LIST_HEAD(&ino->rehash_list);
  53                 ino->active_count = 0;
  54                 INIT_LIST_HEAD(&ino->expiring);
  55                 atomic_set(&ino->count, 0);
  56         }
  57
  58         ino->uid = 0;
  59         ino->gid = 0;
  60         ino->mode = mode;
  61         ino->last_used = jiffies;
  62
  63         ino->sbi = sbi;
  64
  65         if (reinit && ino->free)
  66                 (ino->free)(ino);
  67
  68         memset(&ino->u, 0, sizeof(ino->u));
  69
  70         ino->free = NULL;
  71
  72         if (S_ISLNK(mode))
  73                 ino->free = ino_lnkfree;
  74
  75         return ino;
  76 }
  77
  78 void autofs4_free_ino(struct autofs_info *ino)
  79 {
  80         struct autofs_info *p_ino;
  81
  82         if (ino->dentry) {
  83                 ino->dentry->d_fsdata = NULL;
  84                 if (ino->dentry->d_inode) {
  85                         struct dentry *parent = ino->dentry->d_parent;
  86                         if (atomic_dec_and_test(&ino->count)) {
  87                                 p_ino = autofs4_dentry_ino(parent);
  88                                 if (p_ino && parent != ino->dentry)
  89                                         atomic_dec(&p_ino->count);
  90                         }
  91                         dput(ino->dentry);
  92                 }
  93                 ino->dentry = NULL;
  94         }
  95         if (ino->free)
  96                 (ino->free)(ino);
  97         kfree(ino);
  98 }
  99
 100 /*
 101  * Deal with the infamous "Busy inodes after umount ..." message.
 102  *
 103  * Clean up the dentry tree. This happens with autofs if the user
 104  * space program goes away due to a SIGKILL, SIGSEGV etc.
 105  */
 106 static void autofs4_force_release(struct autofs_sb_info *sbi)
 107 {
 108         struct dentry *this_parent = sbi->sb->s_root;
 109         struct list_head *next;
 110
 111         if (!sbi->sb->s_root)
 112                 return;
 113
 114         spin_lock(&dcache_lock);
 115 repeat:
 116         next = this_parent->d_subdirs.next;
 117 resume:
 118         while (next != &this_parent->d_subdirs) {
 119                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 120
 121                 /* Negative dentry - don`t care */
 122                 if (!simple_positive(dentry)) {
 123                         next = next->next;
 124                         continue;
 125                 }
 126
 127                 if (!list_empty(&dentry->d_subdirs)) {
 128                         this_parent = dentry;
 129                         goto repeat;
 130                 }
 131
 132                 next = next->next;
 133                 spin_unlock(&dcache_lock);
 134
 135                 DPRINTK("dentry %p %.*s",
 136                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 137
 138                 dput(dentry);
 139                 spin_lock(&dcache_lock);
 140         }
 141
 142         if (this_parent != sbi->sb->s_root) {
 143                 struct dentry *dentry = this_parent;
 144
 145                 next = this_parent->d_u.d_child.next;
 146                 this_parent = this_parent->d_parent;
 147                 spin_unlock(&dcache_lock);
 148                 DPRINTK("parent dentry %p %.*s",
 149                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 150                 dput(dentry);
 151                 spin_lock(&dcache_lock);
 152                 goto resume;
 153         }
 154         spin_unlock(&dcache_lock);
 155 }
 156
 157 void autofs4_kill_sb(struct super_block *sb)
 158 {
 159         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 160
 161         /*
 162          * In the event of a failure in get_sb_nodev the superblock
 163          * info is not present so nothing else has been setup, so
 164          * just call kill_anon_super when we are called from
 165          * deactivate_super.
 166          */
 167         if (!sbi)
 168                 goto out_kill_sb;
 169
 170         /* Free wait queues, close pipe */
 171         autofs4_catatonic_mode(sbi);
 172
 173         /* Clean up and release dangling references */
 174         autofs4_force_release(sbi);
 175
 176         sb->s_fs_info = NULL;
 177         kfree(sbi);
 178
 179 out_kill_sb:
 180         DPRINTK("shutting down");
 181         kill_anon_super(sb);
 182 }
 183
 184 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 185 {
 186         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 187         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
 188
 189         if (!sbi)
 190                 return 0;
 191
 192         seq_printf(m, ",fd=%d", sbi->pipefd);
 193         if (root_inode->i_uid != 0)
 194                 seq_printf(m, ",uid=%u", root_inode->i_uid);
 195         if (root_inode->i_gid != 0)
 196                 seq_printf(m, ",gid=%u", root_inode->i_gid);
 197         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 198         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 199         seq_printf(m, ",minproto=%d", sbi->min_proto);
 200         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 201
 202         if (autofs_type_offset(sbi->type))
 203                 seq_printf(m, ",offset");
 204         else if (autofs_type_direct(sbi->type))
 205                 seq_printf(m, ",direct");
 206         else
 207                 seq_printf(m, ",indirect");
 208
 209         return 0;
 210 }
 211
 212 static const struct super_operations autofs4_sops = {
 213         .statfs         = simple_statfs,
 214         .show_options   = autofs4_show_options,
 215 };
 216
 217 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 218         Opt_indirect, Opt_direct, Opt_offset};
 219
 220 static const match_table_t tokens = {
 221         {Opt_fd, "fd=%u"},
 222         {Opt_uid, "uid=%u"},
 223         {Opt_gid, "gid=%u"},
 224         {Opt_pgrp, "pgrp=%u"},
 225         {Opt_minproto, "minproto=%u"},
 226         {Opt_maxproto, "maxproto=%u"},
 227         {Opt_indirect, "indirect"},
 228         {Opt_direct, "direct"},
 229         {Opt_offset, "offset"},
 230         {Opt_err, NULL}
 231 };
 232
 233 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 234                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 235 {
 236         char *p;
 237         substring_t args[MAX_OPT_ARGS];
 238         int option;
 239
 240         *uid = current_uid();
 241         *gid = current_gid();
 242         *pgrp = task_pgrp_nr(current);
 243
 244         *minproto = AUTOFS_MIN_PROTO_VERSION;
 245         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 246
 247         *pipefd = -1;
 248
 249         if (!options)
 250                 return 1;
 251
 252         while ((p = strsep(&options, ",")) != NULL) {
 253                 int token;
 254                 if (!*p)
 255                         continue;
 256
 257                 token = match_token(p, tokens, args);
 258                 switch (token) {
 259                 case Opt_fd:
 260                         if (match_int(args, pipefd))
 261                                 return 1;
 262                         break;
 263                 case Opt_uid:
 264                         if (match_int(args, &option))
 265                                 return 1;
 266                         *uid = option;
 267                         break;
 268                 case Opt_gid:
 269                         if (match_int(args, &option))
 270                                 return 1;
 271                         *gid = option;
 272                         break;
 273                 case Opt_pgrp:
 274                         if (match_int(args, &option))
 275                                 return 1;
 276                         *pgrp = option;
 277                         break;
 278                 case Opt_minproto:
 279                         if (match_int(args, &option))
 280                                 return 1;
 281                         *minproto = option;
 282                         break;
 283                 case Opt_maxproto:
 284                         if (match_int(args, &option))
 285                                 return 1;
 286                         *maxproto = option;
 287                         break;
 288                 case Opt_indirect:
 289                         set_autofs_type_indirect(type);
 290                         break;
 291                 case Opt_direct:
 292                         set_autofs_type_direct(type);
 293                         break;
 294                 case Opt_offset:
 295                         set_autofs_type_offset(type);
 296                         break;
 297                 default:
 298                         return 1;
 299                 }
 300         }
 301         return (*pipefd < 0);
 302 }
 303
 304 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 305 {
 306         struct autofs_info *ino;
 307
 308         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 309         if (!ino)
 310                 return NULL;
 311
 312         return ino;
 313 }
 314
 315 static const struct dentry_operations autofs4_sb_dentry_operations = {
 316         .d_release      = autofs4_dentry_release,
 317 };
 318
 319 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 320 {
 321         struct inode * root_inode;
 322         struct dentry * root;
 323         struct file * pipe;
 324         int pipefd;
 325         struct autofs_sb_info *sbi;
 326         struct autofs_info *ino;
 327
 328         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 329         if (!sbi)
 330                 goto fail_unlock;
 331         DPRINTK("starting up, sbi = %p",sbi);
 332
 333         s->s_fs_info = sbi;
 334         sbi->magic = AUTOFS_SBI_MAGIC;
 335         sbi->pipefd = -1;
 336         sbi->pipe = NULL;
 337         sbi->catatonic = 1;
 338         sbi->exp_timeout = 0;
 339         sbi->oz_pgrp = task_pgrp_nr(current);
 340         sbi->sb = s;
 341         sbi->version = 0;
 342         sbi->sub_version = 0;
 343         set_autofs_type_indirect(&sbi->type);
 344         sbi->min_proto = 0;
 345         sbi->max_proto = 0;
 346         mutex_init(&sbi->wq_mutex);
 347         spin_lock_init(&sbi->fs_lock);
 348         sbi->queues = NULL;
 349         spin_lock_init(&sbi->lookup_lock);
 350         INIT_LIST_HEAD(&sbi->active_list);
 351         INIT_LIST_HEAD(&sbi->expiring_list);
 352         s->s_blocksize = 1024;
 353         s->s_blocksize_bits = 10;
 354         s->s_magic = AUTOFS_SUPER_MAGIC;
 355         s->s_op = &autofs4_sops;
 356         s->s_time_gran = 1;
 357
 358         /*
 359          * Get the root inode and dentry, but defer checking for errors.
 360          */
 361         ino = autofs4_mkroot(sbi);
 362         if (!ino)
 363                 goto fail_free;
 364         root_inode = autofs4_get_inode(s, ino);
 365         if (!root_inode)
 366                 goto fail_ino;
 367
 368         root = d_alloc_root(root_inode);
 369         if (!root)
 370                 goto fail_iput;
 371         pipe = NULL;
 372
 373         root->d_op = &autofs4_sb_dentry_operations;
 374         root->d_fsdata = ino;
 375
 376         /* Can this call block? */
 377         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 378                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 379                                 &sbi->max_proto)) {
 380                 printk("autofs: called with bogus options\n");
 381                 goto fail_dput;
 382         }
 383
 384         root_inode->i_fop = &autofs4_root_operations;
 385         root_inode->i_op = autofs_type_trigger(sbi->type) ?
 386                         &autofs4_direct_root_inode_operations :
 387                         &autofs4_indirect_root_inode_operations;
 388
 389         /* Couldn't this be tested earlier? */
 390         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 391             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 392                 printk("autofs: kernel does not match daemon version "
 393                        "daemon (%d, %d) kernel (%d, %d)\n",
 394                         sbi->min_proto, sbi->max_proto,
 395                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 396                 goto fail_dput;
 397         }
 398
 399         /* Establish highest kernel protocol version */
 400         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 401                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 402         else
 403                 sbi->version = sbi->max_proto;
 404         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 405
 406         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 407         pipe = fget(pipefd);
 408
 409         if (!pipe) {
 410                 printk("autofs: could not open pipe file descriptor\n");
 411                 goto fail_dput;
 412         }
 413         if (!pipe->f_op || !pipe->f_op->write)
 414                 goto fail_fput;
 415         sbi->pipe = pipe;
 416         sbi->pipefd = pipefd;
 417         sbi->catatonic = 0;
 418
 419         /*
 420          * Success! Install the root dentry now to indicate completion.
 421          */
 422         s->s_root = root;
 423         return 0;
 424
 425         /*
 426          * Failure ... clean up.
 427          */
 428 fail_fput:
 429         printk("autofs: pipe file descriptor does not contain proper ops\n");
 430         fput(pipe);
 431         /* fall through */
 432 fail_dput:
 433         dput(root);
 434         goto fail_free;
 435 fail_iput:
 436         printk("autofs: get root dentry failed\n");
 437         iput(root_inode);
 438 fail_ino:
 439         kfree(ino);
 440 fail_free:
 441         kfree(sbi);
 442         s->s_fs_info = NULL;
 443 fail_unlock:
 444         return -EINVAL;
 445 }
 446
 447 struct inode *autofs4_get_inode(struct super_block *sb,
 448                                 struct autofs_info *inf)
 449 {
 450         struct inode *inode = new_inode(sb);
 451
 452         if (inode == NULL)
 453                 return NULL;
 454
 455         inf->inode = inode;
 456         inode->i_mode = inf->mode;
 457         if (sb->s_root) {
 458                 inode->i_uid = sb->s_root->d_inode->i_uid;
 459                 inode->i_gid = sb->s_root->d_inode->i_gid;
 460         }
 461         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 462
 463         if (S_ISDIR(inf->mode)) {
 464                 inode->i_nlink = 2;
 465                 inode->i_op = &autofs4_dir_inode_operations;
 466                 inode->i_fop = &autofs4_dir_operations;
 467         } else if (S_ISLNK(inf->mode)) {
 468                 inode->i_size = inf->size;
 469                 inode->i_op = &autofs4_symlink_inode_operations;
 470         }
 471
 472         return inode;
 473 }