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->expiring);
  53                 atomic_set(&ino->count, 0);
  54         }
  55
  56         ino->uid = 0;
  57         ino->gid = 0;
  58         ino->mode = mode;
  59         ino->last_used = jiffies;
  60
  61         ino->sbi = sbi;
  62
  63         if (reinit && ino->free)
  64                 (ino->free)(ino);
  65
  66         memset(&ino->u, 0, sizeof(ino->u));
  67
  68         ino->free = NULL;
  69
  70         if (S_ISLNK(mode))
  71                 ino->free = ino_lnkfree;
  72
  73         return ino;
  74 }
  75
  76 void autofs4_free_ino(struct autofs_info *ino)
  77 {
  78         struct autofs_info *p_ino;
  79
  80         if (ino->dentry) {
  81                 ino->dentry->d_fsdata = NULL;
  82                 if (ino->dentry->d_inode) {
  83                         struct dentry *parent = ino->dentry->d_parent;
  84                         if (atomic_dec_and_test(&ino->count)) {
  85                                 p_ino = autofs4_dentry_ino(parent);
  86                                 if (p_ino && parent != ino->dentry)
  87                                         atomic_dec(&p_ino->count);
  88                         }
  89                         dput(ino->dentry);
  90                 }
  91                 ino->dentry = NULL;
  92         }
  93         if (ino->free)
  94                 (ino->free)(ino);
  95         kfree(ino);
  96 }
  97
  98 /*
  99  * Deal with the infamous "Busy inodes after umount ..." message.
 100  *
 101  * Clean up the dentry tree. This happens with autofs if the user
 102  * space program goes away due to a SIGKILL, SIGSEGV etc.
 103  */
 104 static void autofs4_force_release(struct autofs_sb_info *sbi)
 105 {
 106         struct dentry *this_parent = sbi->sb->s_root;
 107         struct list_head *next;
 108
 109         if (!sbi->sb->s_root)
 110                 return;
 111
 112         spin_lock(&dcache_lock);
 113 repeat:
 114         next = this_parent->d_subdirs.next;
 115 resume:
 116         while (next != &this_parent->d_subdirs) {
 117                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 118
 119                 /* Negative dentry - don`t care */
 120                 if (!simple_positive(dentry)) {
 121                         next = next->next;
 122                         continue;
 123                 }
 124
 125                 if (!list_empty(&dentry->d_subdirs)) {
 126                         this_parent = dentry;
 127                         goto repeat;
 128                 }
 129
 130                 next = next->next;
 131                 spin_unlock(&dcache_lock);
 132
 133                 DPRINTK("dentry %p %.*s",
 134                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 135
 136                 dput(dentry);
 137                 spin_lock(&dcache_lock);
 138         }
 139
 140         if (this_parent != sbi->sb->s_root) {
 141                 struct dentry *dentry = this_parent;
 142
 143                 next = this_parent->d_u.d_child.next;
 144                 this_parent = this_parent->d_parent;
 145                 spin_unlock(&dcache_lock);
 146                 DPRINTK("parent dentry %p %.*s",
 147                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 148                 dput(dentry);
 149                 spin_lock(&dcache_lock);
 150                 goto resume;
 151         }
 152         spin_unlock(&dcache_lock);
 153 }
 154
 155 void autofs4_kill_sb(struct super_block *sb)
 156 {
 157         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 158
 159         /*
 160          * In the event of a failure in get_sb_nodev the superblock
 161          * info is not present so nothing else has been setup, so
 162          * just call kill_anon_super when we are called from
 163          * deactivate_super.
 164          */
 165         if (!sbi)
 166                 goto out_kill_sb;
 167
 168         /* Free wait queues, close pipe */
 169         autofs4_catatonic_mode(sbi);
 170
 171         /* Clean up and release dangling references */
 172         autofs4_force_release(sbi);
 173
 174         sb->s_fs_info = NULL;
 175         kfree(sbi);
 176
 177 out_kill_sb:
 178         DPRINTK("shutting down");
 179         kill_anon_super(sb);
 180 }
 181
 182 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 183 {
 184         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 185         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
 186
 187         if (!sbi)
 188                 return 0;
 189
 190         seq_printf(m, ",fd=%d", sbi->pipefd);
 191         if (root_inode->i_uid != 0)
 192                 seq_printf(m, ",uid=%u", root_inode->i_uid);
 193         if (root_inode->i_gid != 0)
 194                 seq_printf(m, ",gid=%u", root_inode->i_gid);
 195         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 196         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 197         seq_printf(m, ",minproto=%d", sbi->min_proto);
 198         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 199
 200         if (sbi->type & AUTOFS_TYPE_OFFSET)
 201                 seq_printf(m, ",offset");
 202         else if (sbi->type & AUTOFS_TYPE_DIRECT)
 203                 seq_printf(m, ",direct");
 204         else
 205                 seq_printf(m, ",indirect");
 206
 207         return 0;
 208 }
 209
 210 static const struct super_operations autofs4_sops = {
 211         .statfs         = simple_statfs,
 212         .show_options   = autofs4_show_options,
 213 };
 214
 215 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 216         Opt_indirect, Opt_direct, Opt_offset};
 217
 218 static const match_table_t tokens = {
 219         {Opt_fd, "fd=%u"},
 220         {Opt_uid, "uid=%u"},
 221         {Opt_gid, "gid=%u"},
 222         {Opt_pgrp, "pgrp=%u"},
 223         {Opt_minproto, "minproto=%u"},
 224         {Opt_maxproto, "maxproto=%u"},
 225         {Opt_indirect, "indirect"},
 226         {Opt_direct, "direct"},
 227         {Opt_offset, "offset"},
 228         {Opt_err, NULL}
 229 };
 230
 231 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 232                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 233 {
 234         char *p;
 235         substring_t args[MAX_OPT_ARGS];
 236         int option;
 237
 238         *uid = current->uid;
 239         *gid = current->gid;
 240         *pgrp = task_pgrp_nr(current);
 241
 242         *minproto = AUTOFS_MIN_PROTO_VERSION;
 243         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 244
 245         *pipefd = -1;
 246
 247         if (!options)
 248                 return 1;
 249
 250         while ((p = strsep(&options, ",")) != NULL) {
 251                 int token;
 252                 if (!*p)
 253                         continue;
 254
 255                 token = match_token(p, tokens, args);
 256                 switch (token) {
 257                 case Opt_fd:
 258                         if (match_int(args, pipefd))
 259                                 return 1;
 260                         break;
 261                 case Opt_uid:
 262                         if (match_int(args, &option))
 263                                 return 1;
 264                         *uid = option;
 265                         break;
 266                 case Opt_gid:
 267                         if (match_int(args, &option))
 268                                 return 1;
 269                         *gid = option;
 270                         break;
 271                 case Opt_pgrp:
 272                         if (match_int(args, &option))
 273                                 return 1;
 274                         *pgrp = option;
 275                         break;
 276                 case Opt_minproto:
 277                         if (match_int(args, &option))
 278                                 return 1;
 279                         *minproto = option;
 280                         break;
 281                 case Opt_maxproto:
 282                         if (match_int(args, &option))
 283                                 return 1;
 284                         *maxproto = option;
 285                         break;
 286                 case Opt_indirect:
 287                         *type = AUTOFS_TYPE_INDIRECT;
 288                         break;
 289                 case Opt_direct:
 290                         *type = AUTOFS_TYPE_DIRECT;
 291                         break;
 292                 case Opt_offset:
 293                         *type = AUTOFS_TYPE_OFFSET;
 294                         break;
 295                 default:
 296                         return 1;
 297                 }
 298         }
 299         return (*pipefd < 0);
 300 }
 301
 302 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 303 {
 304         struct autofs_info *ino;
 305
 306         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 307         if (!ino)
 308                 return NULL;
 309
 310         return ino;
 311 }
 312
 313 static struct dentry_operations autofs4_sb_dentry_operations = {
 314         .d_release      = autofs4_dentry_release,
 315 };
 316
 317 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 318 {
 319         struct inode * root_inode;
 320         struct dentry * root;
 321         struct file * pipe;
 322         int pipefd;
 323         struct autofs_sb_info *sbi;
 324         struct autofs_info *ino;
 325
 326         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 327         if (!sbi)
 328                 goto fail_unlock;
 329         DPRINTK("starting up, sbi = %p",sbi);
 330
 331         s->s_fs_info = sbi;
 332         sbi->magic = AUTOFS_SBI_MAGIC;
 333         sbi->pipefd = -1;
 334         sbi->pipe = NULL;
 335         sbi->catatonic = 1;
 336         sbi->exp_timeout = 0;
 337         sbi->oz_pgrp = task_pgrp_nr(current);
 338         sbi->sb = s;
 339         sbi->version = 0;
 340         sbi->sub_version = 0;
 341         sbi->type = AUTOFS_TYPE_INDIRECT;
 342         sbi->min_proto = 0;
 343         sbi->max_proto = 0;
 344         mutex_init(&sbi->wq_mutex);
 345         spin_lock_init(&sbi->fs_lock);
 346         sbi->queues = NULL;
 347         spin_lock_init(&sbi->lookup_lock);
 348         INIT_LIST_HEAD(&sbi->active_list);
 349         INIT_LIST_HEAD(&sbi->expiring_list);
 350         s->s_blocksize = 1024;
 351         s->s_blocksize_bits = 10;
 352         s->s_magic = AUTOFS_SUPER_MAGIC;
 353         s->s_op = &autofs4_sops;
 354         s->s_time_gran = 1;
 355
 356         /*
 357          * Get the root inode and dentry, but defer checking for errors.
 358          */
 359         ino = autofs4_mkroot(sbi);
 360         if (!ino)
 361                 goto fail_free;
 362         root_inode = autofs4_get_inode(s, ino);
 363         if (!root_inode)
 364                 goto fail_ino;
 365
 366         root = d_alloc_root(root_inode);
 367         if (!root)
 368                 goto fail_iput;
 369         pipe = NULL;
 370
 371         root->d_op = &autofs4_sb_dentry_operations;
 372         root->d_fsdata = ino;
 373
 374         /* Can this call block? */
 375         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 376                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 377                                 &sbi->max_proto)) {
 378                 printk("autofs: called with bogus options\n");
 379                 goto fail_dput;
 380         }
 381
 382         root_inode->i_fop = &autofs4_root_operations;
 383         root_inode->i_op = sbi->type & AUTOFS_TYPE_TRIGGER ?
 384                         &autofs4_direct_root_inode_operations :
 385                         &autofs4_indirect_root_inode_operations;
 386
 387         /* Couldn't this be tested earlier? */
 388         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 389             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 390                 printk("autofs: kernel does not match daemon version "
 391                        "daemon (%d, %d) kernel (%d, %d)\n",
 392                         sbi->min_proto, sbi->max_proto,
 393                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 394                 goto fail_dput;
 395         }
 396
 397         /* Establish highest kernel protocol version */
 398         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 399                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 400         else
 401                 sbi->version = sbi->max_proto;
 402         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 403
 404         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 405         pipe = fget(pipefd);
 406
 407         if (!pipe) {
 408                 printk("autofs: could not open pipe file descriptor\n");
 409                 goto fail_dput;
 410         }
 411         if (!pipe->f_op || !pipe->f_op->write)
 412                 goto fail_fput;
 413         sbi->pipe = pipe;
 414         sbi->pipefd = pipefd;
 415         sbi->catatonic = 0;
 416
 417         /*
 418          * Success! Install the root dentry now to indicate completion.
 419          */
 420         s->s_root = root;
 421         return 0;
 422
 423         /*
 424          * Failure ... clean up.
 425          */
 426 fail_fput:
 427         printk("autofs: pipe file descriptor does not contain proper ops\n");
 428         fput(pipe);
 429         /* fall through */
 430 fail_dput:
 431         dput(root);
 432         goto fail_free;
 433 fail_iput:
 434         printk("autofs: get root dentry failed\n");
 435         iput(root_inode);
 436 fail_ino:
 437         kfree(ino);
 438 fail_free:
 439         kfree(sbi);
 440         s->s_fs_info = NULL;
 441 fail_unlock:
 442         return -EINVAL;
 443 }
 444
 445 struct inode *autofs4_get_inode(struct super_block *sb,
 446                                 struct autofs_info *inf)
 447 {
 448         struct inode *inode = new_inode(sb);
 449
 450         if (inode == NULL)
 451                 return NULL;
 452
 453         inf->inode = inode;
 454         inode->i_mode = inf->mode;
 455         if (sb->s_root) {
 456                 inode->i_uid = sb->s_root->d_inode->i_uid;
 457                 inode->i_gid = sb->s_root->d_inode->i_gid;
 458         } else {
 459                 inode->i_uid = 0;
 460                 inode->i_gid = 0;
 461         }
 462         inode->i_blocks = 0;
 463         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 464
 465         if (S_ISDIR(inf->mode)) {
 466                 inode->i_nlink = 2;
 467                 inode->i_op = &autofs4_dir_inode_operations;
 468                 inode->i_fop = &autofs4_dir_operations;
 469         } else if (S_ISLNK(inf->mode)) {
 470                 inode->i_size = inf->size;
 471                 inode->i_op = &autofs4_symlink_inode_operations;
 472         }
 473
 474         return inode;
 475 }