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->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->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         dput(sbi->root);
 144         sbi->root = NULL;
 145         shrink_dcache_sb(sbi->sb);
 146
 147         return;
 148 }
 149
 150 static void autofs4_put_super(struct super_block *sb)
 151 {
 152         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 153
 154         sb->s_fs_info = NULL;
 155
 156         if ( !sbi->catatonic )
 157                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
 158
 159         /* Clean up and release dangling references */
 160         if (sbi)
 161                 autofs4_force_release(sbi);
 162
 163         kfree(sbi);
 164
 165         DPRINTK("shutting down");
 166 }
 167
 168 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 169 {
 170         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 171
 172         if (!sbi)
 173                 return 0;
 174
 175         seq_printf(m, ",fd=%d", sbi->pipefd);
 176         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 177         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 178         seq_printf(m, ",minproto=%d", sbi->min_proto);
 179         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 180
 181         if (sbi->type & AUTOFS_TYP_OFFSET)
 182                 seq_printf(m, ",offset");
 183         else if (sbi->type & AUTOFS_TYP_DIRECT)
 184                 seq_printf(m, ",direct");
 185         else
 186                 seq_printf(m, ",indirect");
 187
 188         return 0;
 189 }
 190
 191 static struct super_operations autofs4_sops = {
 192         .put_super      = autofs4_put_super,
 193         .statfs         = simple_statfs,
 194         .show_options   = autofs4_show_options,
 195 };
 196
 197 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 198         Opt_indirect, Opt_direct, Opt_offset};
 199
 200 static match_table_t tokens = {
 201         {Opt_fd, "fd=%u"},
 202         {Opt_uid, "uid=%u"},
 203         {Opt_gid, "gid=%u"},
 204         {Opt_pgrp, "pgrp=%u"},
 205         {Opt_minproto, "minproto=%u"},
 206         {Opt_maxproto, "maxproto=%u"},
 207         {Opt_indirect, "indirect"},
 208         {Opt_direct, "direct"},
 209         {Opt_offset, "offset"},
 210         {Opt_err, NULL}
 211 };
 212
 213 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 214                          pid_t *pgrp, unsigned int *type,
 215                          int *minproto, int *maxproto)
 216 {
 217         char *p;
 218         substring_t args[MAX_OPT_ARGS];
 219         int option;
 220
 221         *uid = current->uid;
 222         *gid = current->gid;
 223         *pgrp = process_group(current);
 224
 225         *minproto = AUTOFS_MIN_PROTO_VERSION;
 226         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 227
 228         *pipefd = -1;
 229
 230         if (!options)
 231                 return 1;
 232
 233         while ((p = strsep(&options, ",")) != NULL) {
 234                 int token;
 235                 if (!*p)
 236                         continue;
 237
 238                 token = match_token(p, tokens, args);
 239                 switch (token) {
 240                 case Opt_fd:
 241                         if (match_int(args, pipefd))
 242                                 return 1;
 243                         break;
 244                 case Opt_uid:
 245                         if (match_int(args, &option))
 246                                 return 1;
 247                         *uid = option;
 248                         break;
 249                 case Opt_gid:
 250                         if (match_int(args, &option))
 251                                 return 1;
 252                         *gid = option;
 253                         break;
 254                 case Opt_pgrp:
 255                         if (match_int(args, &option))
 256                                 return 1;
 257                         *pgrp = option;
 258                         break;
 259                 case Opt_minproto:
 260                         if (match_int(args, &option))
 261                                 return 1;
 262                         *minproto = option;
 263                         break;
 264                 case Opt_maxproto:
 265                         if (match_int(args, &option))
 266                                 return 1;
 267                         *maxproto = option;
 268                         break;
 269                 case Opt_indirect:
 270                         *type = AUTOFS_TYP_INDIRECT;
 271                         break;
 272                 case Opt_direct:
 273                         *type = AUTOFS_TYP_DIRECT;
 274                         break;
 275                 case Opt_offset:
 276                         *type = AUTOFS_TYP_DIRECT | AUTOFS_TYP_OFFSET;
 277                         break;
 278                 default:
 279                         return 1;
 280                 }
 281         }
 282         return (*pipefd < 0);
 283 }
 284
 285 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 286 {
 287         struct autofs_info *ino;
 288
 289         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 290         if (!ino)
 291                 return NULL;
 292
 293         return ino;
 294 }
 295
 296 void autofs4_dentry_release(struct dentry *);
 297 static struct dentry_operations autofs4_sb_dentry_operations = {
 298         .d_release      = autofs4_dentry_release,
 299 };
 300
 301 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 302 {
 303         struct inode * root_inode;
 304         struct dentry * root;
 305         struct file * pipe;
 306         int pipefd;
 307         struct autofs_sb_info *sbi;
 308         struct autofs_info *ino;
 309
 310         sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
 311         if ( !sbi )
 312                 goto fail_unlock;
 313         DPRINTK("starting up, sbi = %p",sbi);
 314
 315         memset(sbi, 0, sizeof(*sbi));
 316
 317         s->s_fs_info = sbi;
 318         sbi->magic = AUTOFS_SBI_MAGIC;
 319         sbi->root = NULL;
 320         sbi->pipefd = -1;
 321         sbi->catatonic = 0;
 322         sbi->exp_timeout = 0;
 323         sbi->oz_pgrp = process_group(current);
 324         sbi->sb = s;
 325         sbi->version = 0;
 326         sbi->sub_version = 0;
 327         sbi->type = 0;
 328         sbi->min_proto = 0;
 329         sbi->max_proto = 0;
 330         mutex_init(&sbi->wq_mutex);
 331         spin_lock_init(&sbi->fs_lock);
 332         sbi->queues = NULL;
 333         s->s_blocksize = 1024;
 334         s->s_blocksize_bits = 10;
 335         s->s_magic = AUTOFS_SUPER_MAGIC;
 336         s->s_op = &autofs4_sops;
 337         s->s_time_gran = 1;
 338
 339         /*
 340          * Get the root inode and dentry, but defer checking for errors.
 341          */
 342         ino = autofs4_mkroot(sbi);
 343         if (!ino)
 344                 goto fail_free;
 345         root_inode = autofs4_get_inode(s, ino);
 346         if (!root_inode)
 347                 goto fail_ino;
 348
 349         root = d_alloc_root(root_inode);
 350         if (!root)
 351                 goto fail_iput;
 352         pipe = NULL;
 353
 354         root->d_op = &autofs4_sb_dentry_operations;
 355         root->d_fsdata = ino;
 356
 357         /* Can this call block? */
 358         if (parse_options(data, &pipefd,
 359                           &root_inode->i_uid, &root_inode->i_gid,
 360                           &sbi->oz_pgrp, &sbi->type,
 361                           &sbi->min_proto, &sbi->max_proto)) {
 362                 printk("autofs: called with bogus options\n");
 363                 goto fail_dput;
 364         }
 365
 366         root_inode->i_fop = &autofs4_root_operations;
 367         root_inode->i_op = sbi->type & AUTOFS_TYP_DIRECT ?
 368                         &autofs4_direct_root_inode_operations :
 369                         &autofs4_indirect_root_inode_operations;
 370
 371         /* Couldn't this be tested earlier? */
 372         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 373             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 374                 printk("autofs: kernel does not match daemon version "
 375                        "daemon (%d, %d) kernel (%d, %d)\n",
 376                         sbi->min_proto, sbi->max_proto,
 377                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 378                 goto fail_dput;
 379         }
 380
 381         /* Establish highest kernel protocol version */
 382         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 383                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 384         else
 385                 sbi->version = sbi->max_proto;
 386         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 387
 388         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 389         pipe = fget(pipefd);
 390
 391         if ( !pipe ) {
 392                 printk("autofs: could not open pipe file descriptor\n");
 393                 goto fail_dput;
 394         }
 395         if ( !pipe->f_op || !pipe->f_op->write )
 396                 goto fail_fput;
 397         sbi->pipe = pipe;
 398         sbi->pipefd = pipefd;
 399
 400         /*
 401          * Take a reference to the root dentry so we get a chance to
 402          * clean up the dentry tree on umount.
 403          * See autofs4_force_release.
 404          */
 405         sbi->root = dget(root);
 406
 407         /*
 408          * Success! Install the root dentry now to indicate completion.
 409          */
 410         s->s_root = root;
 411         return 0;
 412
 413         /*
 414          * Failure ... clean up.
 415          */
 416 fail_fput:
 417         printk("autofs: pipe file descriptor does not contain proper ops\n");
 418         fput(pipe);
 419         /* fall through */
 420 fail_dput:
 421         dput(root);
 422         goto fail_free;
 423 fail_iput:
 424         printk("autofs: get root dentry failed\n");
 425         iput(root_inode);
 426 fail_ino:
 427         kfree(ino);
 428 fail_free:
 429         kfree(sbi);
 430 fail_unlock:
 431         return -EINVAL;
 432 }
 433
 434 struct inode *autofs4_get_inode(struct super_block *sb,
 435                                 struct autofs_info *inf)
 436 {
 437         struct inode *inode = new_inode(sb);
 438
 439         if (inode == NULL)
 440                 return NULL;
 441
 442         inf->inode = inode;
 443         inode->i_mode = inf->mode;
 444         if (sb->s_root) {
 445                 inode->i_uid = sb->s_root->d_inode->i_uid;
 446                 inode->i_gid = sb->s_root->d_inode->i_gid;
 447         } else {
 448                 inode->i_uid = 0;
 449                 inode->i_gid = 0;
 450         }
 451         inode->i_blksize = PAGE_CACHE_SIZE;
 452         inode->i_blocks = 0;
 453         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 454
 455         if (S_ISDIR(inf->mode)) {
 456                 inode->i_nlink = 2;
 457                 inode->i_op = &autofs4_dir_inode_operations;
 458                 inode->i_fop = &autofs4_dir_operations;
 459         } else if (S_ISLNK(inf->mode)) {
 460                 inode->i_size = inf->size;
 461                 inode->i_op = &autofs4_symlink_inode_operations;
 462         }
 463
 464         return inode;
 465 }