fs/autofs4/inode.c

   1 /* -*- c -*- --------------------------------------------------------------- *
   2  *
   3  * linux/fs/autofs/inode.c
   4  *
   5  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   6  *
   7  * This file is part of the Linux kernel and is made available under
   8  * the terms of the GNU General Public License, version 2, or at your
   9  * option, any later version, incorporated herein by reference.
  10  *
  11  * ------------------------------------------------------------------------- */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/file.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/parser.h>
  18 #include <linux/bitops.h>
  19 #include <linux/smp_lock.h>
  20 #include "autofs_i.h"
  21 #include <linux/module.h>
  22
  23 static void ino_lnkfree(struct autofs_info *ino)
  24 {
  25         kfree(ino->u.symlink);
  26         ino->u.symlink = NULL;
  27 }
  28
  29 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
  30                                      struct autofs_sb_info *sbi, mode_t mode)
  31 {
  32         int reinit = 1;
  33
  34         if (ino == NULL) {
  35                 reinit = 0;
  36                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
  37         }
  38
  39         if (ino == NULL)
  40                 return NULL;
  41
  42         ino->flags = 0;
  43         ino->mode = mode;
  44         ino->inode = NULL;
  45         ino->dentry = NULL;
  46         ino->size = 0;
  47
  48         ino->last_used = jiffies;
  49         atomic_set(&ino->count, 0);
  50
  51         ino->sbi = sbi;
  52
  53         if (reinit && ino->free)
  54                 (ino->free)(ino);
  55
  56         memset(&ino->u, 0, sizeof(ino->u));
  57
  58         ino->free = NULL;
  59
  60         if (S_ISLNK(mode))
  61                 ino->free = ino_lnkfree;
  62
  63         return ino;
  64 }
  65
  66 void autofs4_free_ino(struct autofs_info *ino)
  67 {
  68         struct autofs_info *p_ino;
  69
  70         if (ino->dentry) {
  71                 ino->dentry->d_fsdata = NULL;
  72                 if (ino->dentry->d_inode) {
  73                         struct dentry *parent = ino->dentry->d_parent;
  74                         if (atomic_dec_and_test(&ino->count)) {
  75                                 p_ino = autofs4_dentry_ino(parent);
  76                                 if (p_ino && parent != ino->dentry)
  77                                         atomic_dec(&p_ino->count);
  78                         }
  79                         dput(ino->dentry);
  80                 }
  81                 ino->dentry = NULL;
  82         }
  83         if (ino->free)
  84                 (ino->free)(ino);
  85         kfree(ino);
  86 }
  87
  88 /*
  89  * Deal with the infamous "Busy inodes after umount ..." message.
  90  *
  91  * Clean up the dentry tree. This happens with autofs if the user
  92  * space program goes away due to a SIGKILL, SIGSEGV etc.
  93  */
  94 static void autofs4_force_release(struct autofs_sb_info *sbi)
  95 {
  96         struct dentry *this_parent = sbi->root;
  97         struct list_head *next;
  98
  99         spin_lock(&dcache_lock);
 100 repeat:
 101         next = this_parent->d_subdirs.next;
 102 resume:
 103         while (next != &this_parent->d_subdirs) {
 104                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 105
 106                 /* Negative dentry - don`t care */
 107                 if (!simple_positive(dentry)) {
 108                         next = next->next;
 109                         continue;
 110                 }
 111
 112                 if (!list_empty(&dentry->d_subdirs)) {
 113                         this_parent = dentry;
 114                         goto repeat;
 115                 }
 116
 117                 next = next->next;
 118                 spin_unlock(&dcache_lock);
 119
 120                 DPRINTK("dentry %p %.*s",
 121                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 122
 123                 dput(dentry);
 124                 spin_lock(&dcache_lock);
 125         }
 126
 127         if (this_parent != sbi->root) {
 128                 struct dentry *dentry = this_parent;
 129
 130                 next = this_parent->d_u.d_child.next;
 131                 this_parent = this_parent->d_parent;
 132                 spin_unlock(&dcache_lock);
 133                 DPRINTK("parent dentry %p %.*s",
 134                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 135                 dput(dentry);
 136                 spin_lock(&dcache_lock);
 137                 goto resume;
 138         }
 139         spin_unlock(&dcache_lock);
 140
 141         dput(sbi->root);
 142         sbi->root = NULL;
 143         shrink_dcache_sb(sbi->sb);
 144
 145         return;
 146 }
 147
 148 static void autofs4_put_super(struct super_block *sb)
 149 {
 150         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 151
 152         sb->s_fs_info = NULL;
 153
 154         if ( !sbi->catatonic )
 155                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
 156
 157         /* Clean up and release dangling references */
 158         if (sbi)
 159                 autofs4_force_release(sbi);
 160
 161         kfree(sbi);
 162
 163         DPRINTK("shutting down");
 164 }
 165
 166 static struct super_operations autofs4_sops = {
 167         .put_super      = autofs4_put_super,
 168         .statfs         = simple_statfs,
 169 };
 170
 171 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
 172
 173 static match_table_t tokens = {
 174         {Opt_fd, "fd=%u"},
 175         {Opt_uid, "uid=%u"},
 176         {Opt_gid, "gid=%u"},
 177         {Opt_pgrp, "pgrp=%u"},
 178         {Opt_minproto, "minproto=%u"},
 179         {Opt_maxproto, "maxproto=%u"},
 180         {Opt_err, NULL}
 181 };
 182
 183 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 184                          pid_t *pgrp, int *minproto, int *maxproto)
 185 {
 186         char *p;
 187         substring_t args[MAX_OPT_ARGS];
 188         int option;
 189
 190         *uid = current->uid;
 191         *gid = current->gid;
 192         *pgrp = process_group(current);
 193
 194         *minproto = AUTOFS_MIN_PROTO_VERSION;
 195         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 196
 197         *pipefd = -1;
 198
 199         if (!options)
 200                 return 1;
 201
 202         while ((p = strsep(&options, ",")) != NULL) {
 203                 int token;
 204                 if (!*p)
 205                         continue;
 206
 207                 token = match_token(p, tokens, args);
 208                 switch (token) {
 209                 case Opt_fd:
 210                         if (match_int(args, pipefd))
 211                                 return 1;
 212                         break;
 213                 case Opt_uid:
 214                         if (match_int(args, &option))
 215                                 return 1;
 216                         *uid = option;
 217                         break;
 218                 case Opt_gid:
 219                         if (match_int(args, &option))
 220                                 return 1;
 221                         *gid = option;
 222                         break;
 223                 case Opt_pgrp:
 224                         if (match_int(args, &option))
 225                                 return 1;
 226                         *pgrp = option;
 227                         break;
 228                 case Opt_minproto:
 229                         if (match_int(args, &option))
 230                                 return 1;
 231                         *minproto = option;
 232                         break;
 233                 case Opt_maxproto:
 234                         if (match_int(args, &option))
 235                                 return 1;
 236                         *maxproto = option;
 237                         break;
 238                 default:
 239                         return 1;
 240                 }
 241         }
 242         return (*pipefd < 0);
 243 }
 244
 245 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 246 {
 247         struct autofs_info *ino;
 248
 249         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 250         if (!ino)
 251                 return NULL;
 252
 253         return ino;
 254 }
 255
 256 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 257 {
 258         struct inode * root_inode;
 259         struct dentry * root;
 260         struct file * pipe;
 261         int pipefd;
 262         struct autofs_sb_info *sbi;
 263         struct autofs_info *ino;
 264         int minproto, maxproto;
 265
 266         sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
 267         if ( !sbi )
 268                 goto fail_unlock;
 269         DPRINTK("starting up, sbi = %p",sbi);
 270
 271         memset(sbi, 0, sizeof(*sbi));
 272
 273         s->s_fs_info = sbi;
 274         sbi->magic = AUTOFS_SBI_MAGIC;
 275         sbi->root = NULL;
 276         sbi->catatonic = 0;
 277         sbi->exp_timeout = 0;
 278         sbi->oz_pgrp = process_group(current);
 279         sbi->sb = s;
 280         sbi->version = 0;
 281         sbi->sub_version = 0;
 282         mutex_init(&sbi->wq_mutex);
 283         spin_lock_init(&sbi->fs_lock);
 284         sbi->queues = NULL;
 285         s->s_blocksize = 1024;
 286         s->s_blocksize_bits = 10;
 287         s->s_magic = AUTOFS_SUPER_MAGIC;
 288         s->s_op = &autofs4_sops;
 289         s->s_time_gran = 1;
 290
 291         /*
 292          * Get the root inode and dentry, but defer checking for errors.
 293          */
 294         ino = autofs4_mkroot(sbi);
 295         if (!ino)
 296                 goto fail_free;
 297         root_inode = autofs4_get_inode(s, ino);
 298         kfree(ino);
 299         if (!root_inode)
 300                 goto fail_free;
 301
 302         root_inode->i_op = &autofs4_root_inode_operations;
 303         root_inode->i_fop = &autofs4_root_operations;
 304         root = d_alloc_root(root_inode);
 305         pipe = NULL;
 306
 307         if (!root)
 308                 goto fail_iput;
 309
 310         /* Can this call block? */
 311         if (parse_options(data, &pipefd,
 312                           &root_inode->i_uid, &root_inode->i_gid,
 313                           &sbi->oz_pgrp,
 314                           &minproto, &maxproto)) {
 315                 printk("autofs: called with bogus options\n");
 316                 goto fail_dput;
 317         }
 318
 319         /* Couldn't this be tested earlier? */
 320         if (maxproto < AUTOFS_MIN_PROTO_VERSION ||
 321             minproto > AUTOFS_MAX_PROTO_VERSION) {
 322                 printk("autofs: kernel does not match daemon version "
 323                        "daemon (%d, %d) kernel (%d, %d)\n",
 324                         minproto, maxproto,
 325                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 326                 goto fail_dput;
 327         }
 328
 329         sbi->version = maxproto > AUTOFS_MAX_PROTO_VERSION ? AUTOFS_MAX_PROTO_VERSION : maxproto;
 330         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 331
 332         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 333         pipe = fget(pipefd);
 334
 335         if ( !pipe ) {
 336                 printk("autofs: could not open pipe file descriptor\n");
 337                 goto fail_dput;
 338         }
 339         if ( !pipe->f_op || !pipe->f_op->write )
 340                 goto fail_fput;
 341         sbi->pipe = pipe;
 342
 343         /*
 344          * Take a reference to the root dentry so we get a chance to
 345          * clean up the dentry tree on umount.
 346          * See autofs4_force_release.
 347          */
 348         sbi->root = dget(root);
 349
 350         /*
 351          * Success! Install the root dentry now to indicate completion.
 352          */
 353         s->s_root = root;
 354         return 0;
 355
 356         /*
 357          * Failure ... clean up.
 358          */
 359 fail_fput:
 360         printk("autofs: pipe file descriptor does not contain proper ops\n");
 361         fput(pipe);
 362         /* fall through */
 363 fail_dput:
 364         dput(root);
 365         goto fail_free;
 366 fail_iput:
 367         printk("autofs: get root dentry failed\n");
 368         iput(root_inode);
 369 fail_free:
 370         kfree(sbi);
 371 fail_unlock:
 372         return -EINVAL;
 373 }
 374
 375 struct inode *autofs4_get_inode(struct super_block *sb,
 376                                 struct autofs_info *inf)
 377 {
 378         struct inode *inode = new_inode(sb);
 379
 380         if (inode == NULL)
 381                 return NULL;
 382
 383         inf->inode = inode;
 384         inode->i_mode = inf->mode;
 385         if (sb->s_root) {
 386                 inode->i_uid = sb->s_root->d_inode->i_uid;
 387                 inode->i_gid = sb->s_root->d_inode->i_gid;
 388         } else {
 389                 inode->i_uid = 0;
 390                 inode->i_gid = 0;
 391         }
 392         inode->i_blksize = PAGE_CACHE_SIZE;
 393         inode->i_blocks = 0;
 394         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 395
 396         if (S_ISDIR(inf->mode)) {
 397                 inode->i_nlink = 2;
 398                 inode->i_op = &autofs4_dir_inode_operations;
 399                 inode->i_fop = &autofs4_dir_operations;
 400         } else if (S_ISLNK(inf->mode)) {
 401                 inode->i_size = inf->size;
 402                 inode->i_op = &autofs4_symlink_inode_operations;
 403         }
 404
 405         return inode;
 406 }