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