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