git.oblomov.eu Git - linux-2.6/blob - 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         if (ino->u.symlink) {
  26                 kfree(ino->u.symlink);
  27                 ino->u.symlink = NULL;
  28         }
  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
  52         ino->sbi = sbi;
  53
  54         if (reinit && ino->free)
  55                 (ino->free)(ino);
  56
  57         memset(&ino->u, 0, sizeof(ino->u));
  58
  59         ino->free = NULL;
  60
  61         if (S_ISLNK(mode))
  62                 ino->free = ino_lnkfree;
  63
  64         return ino;
  65 }
  66
  67 void autofs4_free_ino(struct autofs_info *ino)
  68 {
  69         if (ino->dentry) {
  70                 ino->dentry->d_fsdata = NULL;
  71                 if (ino->dentry->d_inode)
  72                         dput(ino->dentry);
  73                 ino->dentry = NULL;
  74         }
  75         if (ino->free)
  76                 (ino->free)(ino);
  77         kfree(ino);
  78 }
  79
  80 /*
  81  * Deal with the infamous "Busy inodes after umount ..." message.
  82  *
  83  * Clean up the dentry tree. This happens with autofs if the user
  84  * space program goes away due to a SIGKILL, SIGSEGV etc.
  85  */
  86 static void autofs4_force_release(struct autofs_sb_info *sbi)
  87 {
  88         struct dentry *this_parent = sbi->root;
  89         struct list_head *next;
  90
  91         spin_lock(&dcache_lock);
  92 repeat:
  93         next = this_parent->d_subdirs.next;
  94 resume:
  95         while (next != &this_parent->d_subdirs) {
  96                 struct dentry *dentry = list_entry(next, struct dentry, d_child);
  97
  98                 /* Negative dentry - don`t care */
  99                 if (!simple_positive(dentry)) {
 100                         next = next->next;
 101                         continue;
 102                 }
 103
 104                 if (!list_empty(&dentry->d_subdirs)) {
 105                         this_parent = dentry;
 106                         goto repeat;
 107                 }
 108
 109                 next = next->next;
 110                 spin_unlock(&dcache_lock);
 111
 112                 DPRINTK("dentry %p %.*s",
 113                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 114
 115                 dput(dentry);
 116                 spin_lock(&dcache_lock);
 117         }
 118
 119         if (this_parent != sbi->root) {
 120                 struct dentry *dentry = this_parent;
 121
 122                 next = this_parent->d_child.next;
 123                 this_parent = this_parent->d_parent;
 124                 spin_unlock(&dcache_lock);
 125                 DPRINTK("parent dentry %p %.*s",
 126                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 127                 dput(dentry);
 128                 spin_lock(&dcache_lock);
 129                 goto resume;
 130         }
 131         spin_unlock(&dcache_lock);
 132
 133         dput(sbi->root);
 134         sbi->root = NULL;
 135         shrink_dcache_sb(sbi->sb);
 136
 137         return;
 138 }
 139
 140 static void autofs4_put_super(struct super_block *sb)
 141 {
 142         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 143
 144         sb->s_fs_info = NULL;
 145
 146         if ( !sbi->catatonic )
 147                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
 148
 149         /* Clean up and release dangling references */
 150         if (sbi)
 151                 autofs4_force_release(sbi);
 152
 153         kfree(sbi);
 154
 155         DPRINTK("shutting down");
 156 }
 157
 158 static struct super_operations autofs4_sops = {
 159         .put_super      = autofs4_put_super,
 160         .statfs         = simple_statfs,
 161 };
 162
 163 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
 164
 165 static match_table_t tokens = {
 166         {Opt_fd, "fd=%u"},
 167         {Opt_uid, "uid=%u"},
 168         {Opt_gid, "gid=%u"},
 169         {Opt_pgrp, "pgrp=%u"},
 170         {Opt_minproto, "minproto=%u"},
 171         {Opt_maxproto, "maxproto=%u"},
 172         {Opt_err, NULL}
 173 };
 174
 175 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 176                          pid_t *pgrp, int *minproto, int *maxproto)
 177 {
 178         char *p;
 179         substring_t args[MAX_OPT_ARGS];
 180         int option;
 181
 182         *uid = current->uid;
 183         *gid = current->gid;
 184         *pgrp = process_group(current);
 185
 186         *minproto = AUTOFS_MIN_PROTO_VERSION;
 187         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 188
 189         *pipefd = -1;
 190
 191         if (!options)
 192                 return 1;
 193
 194         while ((p = strsep(&options, ",")) != NULL) {
 195                 int token;
 196                 if (!*p)
 197                         continue;
 198
 199                 token = match_token(p, tokens, args);
 200                 switch (token) {
 201                 case Opt_fd:
 202                         if (match_int(args, pipefd))
 203                                 return 1;
 204                         break;
 205                 case Opt_uid:
 206                         if (match_int(args, &option))
 207                                 return 1;
 208                         *uid = option;
 209                         break;
 210                 case Opt_gid:
 211                         if (match_int(args, &option))
 212                                 return 1;
 213                         *gid = option;
 214                         break;
 215                 case Opt_pgrp:
 216                         if (match_int(args, &option))
 217                                 return 1;
 218                         *pgrp = option;
 219                         break;
 220                 case Opt_minproto:
 221                         if (match_int(args, &option))
 222                                 return 1;
 223                         *minproto = option;
 224                         break;
 225                 case Opt_maxproto:
 226                         if (match_int(args, &option))
 227                                 return 1;
 228                         *maxproto = option;
 229                         break;
 230                 default:
 231                         return 1;
 232                 }
 233         }
 234         return (*pipefd < 0);
 235 }
 236
 237 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 238 {
 239         struct autofs_info *ino;
 240
 241         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 242         if (!ino)
 243                 return NULL;
 244
 245         return ino;
 246 }
 247
 248 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 249 {
 250         struct inode * root_inode;
 251         struct dentry * root;
 252         struct file * pipe;
 253         int pipefd;
 254         struct autofs_sb_info *sbi;
 255         struct autofs_info *ino;
 256         int minproto, maxproto;
 257
 258         sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
 259         if ( !sbi )
 260                 goto fail_unlock;
 261         DPRINTK("starting up, sbi = %p",sbi);
 262
 263         memset(sbi, 0, sizeof(*sbi));
 264
 265         s->s_fs_info = sbi;
 266         sbi->magic = AUTOFS_SBI_MAGIC;
 267         sbi->root = NULL;
 268         sbi->catatonic = 0;
 269         sbi->exp_timeout = 0;
 270         sbi->oz_pgrp = process_group(current);
 271         sbi->sb = s;
 272         sbi->version = 0;
 273         sbi->sub_version = 0;
 274         init_MUTEX(&sbi->wq_sem);
 275         spin_lock_init(&sbi->fs_lock);
 276         sbi->queues = NULL;
 277         s->s_blocksize = 1024;
 278         s->s_blocksize_bits = 10;
 279         s->s_magic = AUTOFS_SUPER_MAGIC;
 280         s->s_op = &autofs4_sops;
 281         s->s_time_gran = 1;
 282
 283         /*
 284          * Get the root inode and dentry, but defer checking for errors.
 285          */
 286         ino = autofs4_mkroot(sbi);
 287         if (!ino)
 288                 goto fail_free;
 289         root_inode = autofs4_get_inode(s, ino);
 290         kfree(ino);
 291         if (!root_inode)
 292                 goto fail_free;
 293
 294         root_inode->i_op = &autofs4_root_inode_operations;
 295         root_inode->i_fop = &autofs4_root_operations;
 296         root = d_alloc_root(root_inode);
 297         pipe = NULL;
 298
 299         if (!root)
 300                 goto fail_iput;
 301
 302         /* Can this call block? */
 303         if (parse_options(data, &pipefd,
 304                           &root_inode->i_uid, &root_inode->i_gid,
 305                           &sbi->oz_pgrp,
 306                           &minproto, &maxproto)) {
 307                 printk("autofs: called with bogus options\n");
 308                 goto fail_dput;
 309         }
 310
 311         /* Couldn't this be tested earlier? */
 312         if (maxproto < AUTOFS_MIN_PROTO_VERSION ||
 313             minproto > AUTOFS_MAX_PROTO_VERSION) {
 314                 printk("autofs: kernel does not match daemon version "
 315                        "daemon (%d, %d) kernel (%d, %d)\n",
 316                         minproto, maxproto,
 317                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 318                 goto fail_dput;
 319         }
 320
 321         sbi->version = maxproto > AUTOFS_MAX_PROTO_VERSION ? AUTOFS_MAX_PROTO_VERSION : maxproto;
 322         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 323
 324         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 325         pipe = fget(pipefd);
 326
 327         if ( !pipe ) {
 328                 printk("autofs: could not open pipe file descriptor\n");
 329                 goto fail_dput;
 330         }
 331         if ( !pipe->f_op || !pipe->f_op->write )
 332                 goto fail_fput;
 333         sbi->pipe = pipe;
 334
 335         /*
 336          * Take a reference to the root dentry so we get a chance to
 337          * clean up the dentry tree on umount.
 338          * See autofs4_force_release.
 339          */
 340         sbi->root = dget(root);
 341
 342         /*
 343          * Success! Install the root dentry now to indicate completion.
 344          */
 345         s->s_root = root;
 346         return 0;
 347
 348         /*
 349          * Failure ... clean up.
 350          */
 351 fail_fput:
 352         printk("autofs: pipe file descriptor does not contain proper ops\n");
 353         fput(pipe);
 354         /* fall through */
 355 fail_dput:
 356         dput(root);
 357         goto fail_free;
 358 fail_iput:
 359         printk("autofs: get root dentry failed\n");
 360         iput(root_inode);
 361 fail_free:
 362         kfree(sbi);
 363 fail_unlock:
 364         return -EINVAL;
 365 }
 366
 367 struct inode *autofs4_get_inode(struct super_block *sb,
 368                                 struct autofs_info *inf)
 369 {
 370         struct inode *inode = new_inode(sb);
 371
 372         if (inode == NULL)
 373                 return NULL;
 374
 375         inf->inode = inode;
 376         inode->i_mode = inf->mode;
 377         if (sb->s_root) {
 378                 inode->i_uid = sb->s_root->d_inode->i_uid;
 379                 inode->i_gid = sb->s_root->d_inode->i_gid;
 380         } else {
 381                 inode->i_uid = 0;
 382                 inode->i_gid = 0;
 383         }
 384         inode->i_blksize = PAGE_CACHE_SIZE;
 385         inode->i_blocks = 0;
 386         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 387
 388         if (S_ISDIR(inf->mode)) {
 389                 inode->i_nlink = 2;
 390                 inode->i_op = &autofs4_dir_inode_operations;
 391                 inode->i_fop = &autofs4_dir_operations;
 392         } else if (S_ISLNK(inf->mode)) {
 393                 inode->i_size = inf->size;
 394                 inode->i_op = &autofs4_symlink_inode_operations;
 395         }
 396
 397         return inode;
 398 }