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/magic.h>
  22 #include "autofs_i.h"
  23 #include <linux/module.h>
  24
  25 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
  26                                      struct autofs_sb_info *sbi, mode_t mode)
  27 {
  28         int reinit = 1;
  29
  30         if (ino == NULL) {
  31                 reinit = 0;
  32                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
  33         }
  34
  35         if (ino == NULL)
  36                 return NULL;
  37
  38         if (!reinit) {
  39                 ino->flags = 0;
  40                 ino->dentry = NULL;
  41                 ino->size = 0;
  42                 INIT_LIST_HEAD(&ino->active);
  43                 ino->active_count = 0;
  44                 INIT_LIST_HEAD(&ino->expiring);
  45                 atomic_set(&ino->count, 0);
  46         }
  47
  48         ino->uid = 0;
  49         ino->gid = 0;
  50         ino->mode = mode;
  51         ino->last_used = jiffies;
  52
  53         ino->sbi = sbi;
  54
  55         return ino;
  56 }
  57
  58 void autofs4_free_ino(struct autofs_info *ino)
  59 {
  60         if (ino->dentry) {
  61                 ino->dentry->d_fsdata = NULL;
  62                 ino->dentry = NULL;
  63         }
  64         kfree(ino);
  65 }
  66
  67 void autofs4_kill_sb(struct super_block *sb)
  68 {
  69         struct autofs_sb_info *sbi = autofs4_sbi(sb);
  70
  71         /*
  72          * In the event of a failure in get_sb_nodev the superblock
  73          * info is not present so nothing else has been setup, so
  74          * just call kill_anon_super when we are called from
  75          * deactivate_super.
  76          */
  77         if (!sbi)
  78                 goto out_kill_sb;
  79
  80         /* Free wait queues, close pipe */
  81         autofs4_catatonic_mode(sbi);
  82
  83         sb->s_fs_info = NULL;
  84         kfree(sbi);
  85
  86 out_kill_sb:
  87         DPRINTK("shutting down");
  88         kill_litter_super(sb);
  89 }
  90
  91 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
  92 {
  93         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
  94         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
  95
  96         if (!sbi)
  97                 return 0;
  98
  99         seq_printf(m, ",fd=%d", sbi->pipefd);
 100         if (root_inode->i_uid != 0)
 101                 seq_printf(m, ",uid=%u", root_inode->i_uid);
 102         if (root_inode->i_gid != 0)
 103                 seq_printf(m, ",gid=%u", root_inode->i_gid);
 104         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 105         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 106         seq_printf(m, ",minproto=%d", sbi->min_proto);
 107         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 108
 109         if (autofs_type_offset(sbi->type))
 110                 seq_printf(m, ",offset");
 111         else if (autofs_type_direct(sbi->type))
 112                 seq_printf(m, ",direct");
 113         else
 114                 seq_printf(m, ",indirect");
 115
 116         return 0;
 117 }
 118
 119 static void autofs4_evict_inode(struct inode *inode)
 120 {
 121         end_writeback(inode);
 122         kfree(inode->i_private);
 123 }
 124
 125 static const struct super_operations autofs4_sops = {
 126         .statfs         = simple_statfs,
 127         .show_options   = autofs4_show_options,
 128         .evict_inode    = autofs4_evict_inode,
 129 };
 130
 131 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 132         Opt_indirect, Opt_direct, Opt_offset};
 133
 134 static const match_table_t tokens = {
 135         {Opt_fd, "fd=%u"},
 136         {Opt_uid, "uid=%u"},
 137         {Opt_gid, "gid=%u"},
 138         {Opt_pgrp, "pgrp=%u"},
 139         {Opt_minproto, "minproto=%u"},
 140         {Opt_maxproto, "maxproto=%u"},
 141         {Opt_indirect, "indirect"},
 142         {Opt_direct, "direct"},
 143         {Opt_offset, "offset"},
 144         {Opt_err, NULL}
 145 };
 146
 147 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 148                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 149 {
 150         char *p;
 151         substring_t args[MAX_OPT_ARGS];
 152         int option;
 153
 154         *uid = current_uid();
 155         *gid = current_gid();
 156         *pgrp = task_pgrp_nr(current);
 157
 158         *minproto = AUTOFS_MIN_PROTO_VERSION;
 159         *maxproto = AUTOFS_MAX_PROTO_VERSION;
 160
 161         *pipefd = -1;
 162
 163         if (!options)
 164                 return 1;
 165
 166         while ((p = strsep(&options, ",")) != NULL) {
 167                 int token;
 168                 if (!*p)
 169                         continue;
 170
 171                 token = match_token(p, tokens, args);
 172                 switch (token) {
 173                 case Opt_fd:
 174                         if (match_int(args, pipefd))
 175                                 return 1;
 176                         break;
 177                 case Opt_uid:
 178                         if (match_int(args, &option))
 179                                 return 1;
 180                         *uid = option;
 181                         break;
 182                 case Opt_gid:
 183                         if (match_int(args, &option))
 184                                 return 1;
 185                         *gid = option;
 186                         break;
 187                 case Opt_pgrp:
 188                         if (match_int(args, &option))
 189                                 return 1;
 190                         *pgrp = option;
 191                         break;
 192                 case Opt_minproto:
 193                         if (match_int(args, &option))
 194                                 return 1;
 195                         *minproto = option;
 196                         break;
 197                 case Opt_maxproto:
 198                         if (match_int(args, &option))
 199                                 return 1;
 200                         *maxproto = option;
 201                         break;
 202                 case Opt_indirect:
 203                         set_autofs_type_indirect(type);
 204                         break;
 205                 case Opt_direct:
 206                         set_autofs_type_direct(type);
 207                         break;
 208                 case Opt_offset:
 209                         set_autofs_type_offset(type);
 210                         break;
 211                 default:
 212                         return 1;
 213                 }
 214         }
 215         return (*pipefd < 0);
 216 }
 217
 218 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 219 {
 220         struct inode * root_inode;
 221         struct dentry * root;
 222         struct file * pipe;
 223         int pipefd;
 224         struct autofs_sb_info *sbi;
 225         struct autofs_info *ino;
 226
 227         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 228         if (!sbi)
 229                 goto fail_unlock;
 230         DPRINTK("starting up, sbi = %p",sbi);
 231
 232         s->s_fs_info = sbi;
 233         sbi->magic = AUTOFS_SBI_MAGIC;
 234         sbi->pipefd = -1;
 235         sbi->pipe = NULL;
 236         sbi->catatonic = 1;
 237         sbi->exp_timeout = 0;
 238         sbi->oz_pgrp = task_pgrp_nr(current);
 239         sbi->sb = s;
 240         sbi->version = 0;
 241         sbi->sub_version = 0;
 242         set_autofs_type_indirect(&sbi->type);
 243         sbi->min_proto = 0;
 244         sbi->max_proto = 0;
 245         mutex_init(&sbi->wq_mutex);
 246         spin_lock_init(&sbi->fs_lock);
 247         sbi->queues = NULL;
 248         spin_lock_init(&sbi->lookup_lock);
 249         INIT_LIST_HEAD(&sbi->active_list);
 250         INIT_LIST_HEAD(&sbi->expiring_list);
 251         s->s_blocksize = 1024;
 252         s->s_blocksize_bits = 10;
 253         s->s_magic = AUTOFS_SUPER_MAGIC;
 254         s->s_op = &autofs4_sops;
 255         s->s_d_op = &autofs4_dentry_operations;
 256         s->s_time_gran = 1;
 257
 258         /*
 259          * Get the root inode and dentry, but defer checking for errors.
 260          */
 261         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 262         if (!ino)
 263                 goto fail_free;
 264         root_inode = autofs4_get_inode(s, ino);
 265         if (!root_inode)
 266                 goto fail_ino;
 267
 268         root = d_alloc_root(root_inode);
 269         if (!root)
 270                 goto fail_iput;
 271         pipe = NULL;
 272
 273         root->d_fsdata = ino;
 274
 275         /* Can this call block? */
 276         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 277                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 278                                 &sbi->max_proto)) {
 279                 printk("autofs: called with bogus options\n");
 280                 goto fail_dput;
 281         }
 282
 283         if (autofs_type_trigger(sbi->type))
 284                 __managed_dentry_set_managed(root);
 285
 286         root_inode->i_fop = &autofs4_root_operations;
 287         root_inode->i_op = &autofs4_dir_inode_operations;
 288
 289         /* Couldn't this be tested earlier? */
 290         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 291             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 292                 printk("autofs: kernel does not match daemon version "
 293                        "daemon (%d, %d) kernel (%d, %d)\n",
 294                         sbi->min_proto, sbi->max_proto,
 295                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 296                 goto fail_dput;
 297         }
 298
 299         /* Establish highest kernel protocol version */
 300         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 301                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
 302         else
 303                 sbi->version = sbi->max_proto;
 304         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 305
 306         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 307         pipe = fget(pipefd);
 308
 309         if (!pipe) {
 310                 printk("autofs: could not open pipe file descriptor\n");
 311                 goto fail_dput;
 312         }
 313         if (!pipe->f_op || !pipe->f_op->write)
 314                 goto fail_fput;
 315         sbi->pipe = pipe;
 316         sbi->pipefd = pipefd;
 317         sbi->catatonic = 0;
 318
 319         /*
 320          * Success! Install the root dentry now to indicate completion.
 321          */
 322         s->s_root = root;
 323         return 0;
 324
 325         /*
 326          * Failure ... clean up.
 327          */
 328 fail_fput:
 329         printk("autofs: pipe file descriptor does not contain proper ops\n");
 330         fput(pipe);
 331         /* fall through */
 332 fail_dput:
 333         dput(root);
 334         goto fail_free;
 335 fail_iput:
 336         printk("autofs: get root dentry failed\n");
 337         iput(root_inode);
 338 fail_ino:
 339         kfree(ino);
 340 fail_free:
 341         kfree(sbi);
 342         s->s_fs_info = NULL;
 343 fail_unlock:
 344         return -EINVAL;
 345 }
 346
 347 struct inode *autofs4_get_inode(struct super_block *sb,
 348                                 struct autofs_info *inf)
 349 {
 350         struct inode *inode = new_inode(sb);
 351
 352         if (inode == NULL)
 353                 return NULL;
 354
 355         inode->i_mode = inf->mode;
 356         if (sb->s_root) {
 357                 inode->i_uid = sb->s_root->d_inode->i_uid;
 358                 inode->i_gid = sb->s_root->d_inode->i_gid;
 359         }
 360         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 361         inode->i_ino = get_next_ino();
 362
 363         if (S_ISDIR(inf->mode)) {
 364                 inode->i_nlink = 2;
 365                 inode->i_op = &autofs4_dir_inode_operations;
 366                 inode->i_fop = &autofs4_dir_operations;
 367         } else if (S_ISLNK(inf->mode)) {
 368                 inode->i_size = inf->size;
 369                 inode->i_op = &autofs4_symlink_inode_operations;
 370         }
 371
 372         return inode;
 373 }