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/seq_file.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/parser.h>
  19 #include <linux/bitops.h>
  20 #include <linux/smp_lock.h>
  21 #include "autofs_i.h"
  22 #include <linux/module.h>
  23
  24 static void ino_lnkfree(struct autofs_info *ino)
  25 {
  26         kfree(ino->u.symlink);
  27         ino->u.symlink = NULL;
  28 }
  29
  30 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
  31                                      struct autofs_sb_info *sbi, mode_t mode)
  32 {
  33         int reinit = 1;
  34
  35         if (ino == NULL) {
  36                 reinit = 0;
  37                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
  38         }
  39
  40         if (ino == NULL)
  41                 return NULL;
  42
  43         ino->flags = 0;
  44         ino->mode = mode;
  45         ino->inode = NULL;
  46         ino->dentry = NULL;
  47         ino->size = 0;
  48
  49         ino->last_used = jiffies;
  50         atomic_set(&ino->count, 0);
  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         struct autofs_info *p_ino;
  70
  71         if (ino->dentry) {
  72                 ino->dentry->d_fsdata = NULL;
  73                 if (ino->dentry->d_inode) {
  74                         struct dentry *parent = ino->dentry->d_parent;
  75                         if (atomic_dec_and_test(&ino->count)) {
  76                                 p_ino = autofs4_dentry_ino(parent);
  77                                 if (p_ino && parent != ino->dentry)
  78                                         atomic_dec(&p_ino->count);
  79                         }
  80                         dput(ino->dentry);
  81                 }
  82                 ino->dentry = NULL;
  83         }
  84         if (ino->free)
  85                 (ino->free)(ino);
  86         kfree(ino);
  87 }
  88
  89 /*
  90  * Deal with the infamous "Busy inodes after umount ..." message.
  91  *
  92  * Clean up the dentry tree. This happens with autofs if the user
  93  * space program goes away due to a SIGKILL, SIGSEGV etc.
  94  */
  95 static void autofs4_force_release(struct autofs_sb_info *sbi)
  96 {
  97         struct dentry *this_parent = sbi->root;
  98         struct list_head *next;
  99
 100         spin_lock(&dcache_lock);
 101 repeat:
 102         next = this_parent->d_subdirs.next;
 103 resume:
 104         while (next != &this_parent->d_subdirs) {
 105                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 106
 107                 /* Negative dentry - don`t care */
 108                 if (!simple_positive(dentry)) {
 109                         next = next->next;
 110                         continue;
 111                 }
 112
 113                 if (!list_empty(&dentry->d_subdirs)) {
 114                         this_parent = dentry;
 115                         goto repeat;
 116                 }
 117
 118                 next = next->next;
 119                 spin_unlock(&dcache_lock);
 120
 121                 DPRINTK("dentry %p %.*s",
 122                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 123
 124                 dput(dentry);
 125                 spin_lock(&dcache_lock);
 126         }
 127
 128         if (this_parent != sbi->root) {
 129                 struct dentry *dentry = this_parent;
 130
 131                 next = this_parent->d_u.d_child.next;
 132                 this_parent = this_parent->d_parent;
 133                 spin_unlock(&dcache_lock);
 134                 DPRINTK("parent dentry %p %.*s",
 135                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
 136                 dput(dentry);
 137                 spin_lock(&dcache_lock);
 138                 goto resume;
 139         }
 140         spin_unlock(&dcache_lock);
 141
 142         dput(sbi->root);
 143         sbi->root = NULL;
 144         shrink_dcache_sb(sbi->sb);
 145
 146         return;
 147 }
 148
 149 static void autofs4_put_super(struct super_block *sb)
 150 {
 151         struct autofs_sb_info *sbi = autofs4_sbi(sb);
 152
 153         sb->s_fs_info = NULL;
 154
 155         if ( !sbi->catatonic )
 156                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
 157
 158         /* Clean up and release dangling references */
 159         if (sbi)
 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         return 0;
 181 }
 182
 183 static struct super_operations autofs4_sops = {
 184         .put_super      = autofs4_put_super,
 185         .statfs         = simple_statfs,
 186         .show_options   = autofs4_show_options,
 187 };
 188
 189 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
 190
 191 static match_table_t tokens = {
 192         {Opt_fd, "fd=%u"},
 193         {Opt_uid, "uid=%u"},
 194         {Opt_gid, "gid=%u"},
 195         {Opt_pgrp, "pgrp=%u"},
 196         {Opt_minproto, "minproto=%u"},
 197         {Opt_maxproto, "maxproto=%u"},
 198         {Opt_err, NULL}
 199 };
 200
 201 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 202                          pid_t *pgrp, int *minproto, int *maxproto)
 203 {
 204         char *p;
 205         substring_t args[MAX_OPT_ARGS];
 206         int option;
 207
 208         *uid = current->uid;
 209         *gid = current->gid;
 210         *pgrp = process_group(current);
 211
 212         *minproto = AUTOFS_MIN_PROTO_VERSION;
 213         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 214
 215         *pipefd = -1;
 216
 217         if (!options)
 218                 return 1;
 219
 220         while ((p = strsep(&options, ",")) != NULL) {
 221                 int token;
 222                 if (!*p)
 223                         continue;
 224
 225                 token = match_token(p, tokens, args);
 226                 switch (token) {
 227                 case Opt_fd:
 228                         if (match_int(args, pipefd))
 229                                 return 1;
 230                         break;
 231                 case Opt_uid:
 232                         if (match_int(args, &option))
 233                                 return 1;
 234                         *uid = option;
 235                         break;
 236                 case Opt_gid:
 237                         if (match_int(args, &option))
 238                                 return 1;
 239                         *gid = option;
 240                         break;
 241                 case Opt_pgrp:
 242                         if (match_int(args, &option))
 243                                 return 1;
 244                         *pgrp = option;
 245                         break;
 246                 case Opt_minproto:
 247                         if (match_int(args, &option))
 248                                 return 1;
 249                         *minproto = option;
 250                         break;
 251                 case Opt_maxproto:
 252                         if (match_int(args, &option))
 253                                 return 1;
 254                         *maxproto = option;
 255                         break;
 256                 default:
 257                         return 1;
 258                 }
 259         }
 260         return (*pipefd < 0);
 261 }
 262
 263 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 264 {
 265         struct autofs_info *ino;
 266
 267         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 268         if (!ino)
 269                 return NULL;
 270
 271         return ino;
 272 }
 273
 274 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 275 {
 276         struct inode * root_inode;
 277         struct dentry * root;
 278         struct file * pipe;
 279         int pipefd;
 280         struct autofs_sb_info *sbi;
 281         struct autofs_info *ino;
 282
 283         sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
 284         if ( !sbi )
 285                 goto fail_unlock;
 286         DPRINTK("starting up, sbi = %p",sbi);
 287
 288         memset(sbi, 0, sizeof(*sbi));
 289
 290         s->s_fs_info = sbi;
 291         sbi->magic = AUTOFS_SBI_MAGIC;
 292         sbi->root = NULL;
 293         sbi->pipefd = -1;
 294         sbi->catatonic = 0;
 295         sbi->exp_timeout = 0;
 296         sbi->oz_pgrp = process_group(current);
 297         sbi->sb = s;
 298         sbi->version = 0;
 299         sbi->sub_version = 0;
 300         sbi->min_proto = 0;
 301         sbi->max_proto = 0;
 302         mutex_init(&sbi->wq_mutex);
 303         spin_lock_init(&sbi->fs_lock);
 304         sbi->queues = NULL;
 305         s->s_blocksize = 1024;
 306         s->s_blocksize_bits = 10;
 307         s->s_magic = AUTOFS_SUPER_MAGIC;
 308         s->s_op = &autofs4_sops;
 309         s->s_time_gran = 1;
 310
 311         /*
 312          * Get the root inode and dentry, but defer checking for errors.
 313          */
 314         ino = autofs4_mkroot(sbi);
 315         if (!ino)
 316                 goto fail_free;
 317         root_inode = autofs4_get_inode(s, ino);
 318         kfree(ino);
 319         if (!root_inode)
 320                 goto fail_free;
 321
 322         root_inode->i_op = &autofs4_root_inode_operations;
 323         root_inode->i_fop = &autofs4_root_operations;
 324         root = d_alloc_root(root_inode);
 325         pipe = NULL;
 326
 327         if (!root)
 328                 goto fail_iput;
 329
 330         /* Can this call block? */
 331         if (parse_options(data, &pipefd,
 332                           &root_inode->i_uid, &root_inode->i_gid,
 333                           &sbi->oz_pgrp,
 334                           &sbi->min_proto, &sbi->max_proto)) {
 335                 printk("autofs: called with bogus options\n");
 336                 goto fail_dput;
 337         }
 338
 339         /* Couldn't this be tested earlier? */
 340         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 341             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 342                 printk("autofs: kernel does not match daemon version "
 343                        "daemon (%d, %d) kernel (%d, %d)\n",
 344                         sbi->min_proto, sbi->max_proto,
 345                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 346                 goto fail_dput;
 347         }
 348
 349         /* Establish highest kernel protocol version */
 350         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 351                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 352         else
 353                 sbi->version = sbi->max_proto;
 354         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 355
 356         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 357         pipe = fget(pipefd);
 358
 359         if ( !pipe ) {
 360                 printk("autofs: could not open pipe file descriptor\n");
 361                 goto fail_dput;
 362         }
 363         if ( !pipe->f_op || !pipe->f_op->write )
 364                 goto fail_fput;
 365         sbi->pipe = pipe;
 366         sbi->pipefd = pipefd;
 367
 368         /*
 369          * Take a reference to the root dentry so we get a chance to
 370          * clean up the dentry tree on umount.
 371          * See autofs4_force_release.
 372          */
 373         sbi->root = dget(root);
 374
 375         /*
 376          * Success! Install the root dentry now to indicate completion.
 377          */
 378         s->s_root = root;
 379         return 0;
 380
 381         /*
 382          * Failure ... clean up.
 383          */
 384 fail_fput:
 385         printk("autofs: pipe file descriptor does not contain proper ops\n");
 386         fput(pipe);
 387         /* fall through */
 388 fail_dput:
 389         dput(root);
 390         goto fail_free;
 391 fail_iput:
 392         printk("autofs: get root dentry failed\n");
 393         iput(root_inode);
 394 fail_free:
 395         kfree(sbi);
 396 fail_unlock:
 397         return -EINVAL;
 398 }
 399
 400 struct inode *autofs4_get_inode(struct super_block *sb,
 401                                 struct autofs_info *inf)
 402 {
 403         struct inode *inode = new_inode(sb);
 404
 405         if (inode == NULL)
 406                 return NULL;
 407
 408         inf->inode = inode;
 409         inode->i_mode = inf->mode;
 410         if (sb->s_root) {
 411                 inode->i_uid = sb->s_root->d_inode->i_uid;
 412                 inode->i_gid = sb->s_root->d_inode->i_gid;
 413         } else {
 414                 inode->i_uid = 0;
 415                 inode->i_gid = 0;
 416         }
 417         inode->i_blksize = PAGE_CACHE_SIZE;
 418         inode->i_blocks = 0;
 419         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 420
 421         if (S_ISDIR(inf->mode)) {
 422                 inode->i_nlink = 2;
 423                 inode->i_op = &autofs4_dir_inode_operations;
 424                 inode->i_fop = &autofs4_dir_operations;
 425         } else if (S_ISLNK(inf->mode)) {
 426                 inode->i_size = inf->size;
 427                 inode->i_op = &autofs4_symlink_inode_operations;
 428         }
 429
 430         return inode;
 431 }