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