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