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