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