linux/fs/autofs4/inode.c
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   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
  25static void ino_lnkfree(struct autofs_info *ino)
  26{
  27        if (ino->u.symlink) {
  28                kfree(ino->u.symlink);
  29                ino->u.symlink = NULL;
  30        }
  31}
  32
  33struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
  34                                     struct autofs_sb_info *sbi, mode_t mode)
  35{
  36        int reinit = 1;
  37
  38        if (ino == NULL) {
  39                reinit = 0;
  40                ino = kmalloc(sizeof(*ino), GFP_KERNEL);
  41        }
  42
  43        if (ino == NULL)
  44                return NULL;
  45
  46        if (!reinit) {
  47                ino->flags = 0;
  48                ino->inode = NULL;
  49                ino->dentry = NULL;
  50                ino->size = 0;
  51                INIT_LIST_HEAD(&ino->active);
  52                ino->active_count = 0;
  53                INIT_LIST_HEAD(&ino->expiring);
  54                atomic_set(&ino->count, 0);
  55        }
  56
  57        ino->uid = 0;
  58        ino->gid = 0;
  59        ino->mode = mode;
  60        ino->last_used = jiffies;
  61
  62        ino->sbi = sbi;
  63
  64        if (reinit && ino->free)
  65                (ino->free)(ino);
  66
  67        memset(&ino->u, 0, sizeof(ino->u));
  68
  69        ino->free = NULL;
  70
  71        if (S_ISLNK(mode))
  72                ino->free = ino_lnkfree;
  73
  74        return ino;
  75}
  76
  77void autofs4_free_ino(struct autofs_info *ino)
  78{
  79        struct autofs_info *p_ino;
  80
  81        if (ino->dentry) {
  82                ino->dentry->d_fsdata = NULL;
  83                if (ino->dentry->d_inode) {
  84                        struct dentry *parent = ino->dentry->d_parent;
  85                        if (atomic_dec_and_test(&ino->count)) {
  86                                p_ino = autofs4_dentry_ino(parent);
  87                                if (p_ino && parent != ino->dentry)
  88                                        atomic_dec(&p_ino->count);
  89                        }
  90                        dput(ino->dentry);
  91                }
  92                ino->dentry = NULL;
  93        }
  94        if (ino->free)
  95                (ino->free)(ino);
  96        kfree(ino);
  97}
  98
  99void autofs4_kill_sb(struct super_block *sb)
 100{
 101        struct autofs_sb_info *sbi = autofs4_sbi(sb);
 102
 103        /*
 104         * In the event of a failure in get_sb_nodev the superblock
 105         * info is not present so nothing else has been setup, so
 106         * just call kill_anon_super when we are called from
 107         * deactivate_super.
 108         */
 109        if (!sbi)
 110                goto out_kill_sb;
 111
 112        /* Free wait queues, close pipe */
 113        autofs4_catatonic_mode(sbi);
 114
 115        sb->s_fs_info = NULL;
 116        kfree(sbi);
 117
 118out_kill_sb:
 119        DPRINTK("shutting down");
 120        kill_litter_super(sb);
 121}
 122
 123static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 124{
 125        struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 126        struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
 127
 128        if (!sbi)
 129                return 0;
 130
 131        seq_printf(m, ",fd=%d", sbi->pipefd);
 132        if (root_inode->i_uid != 0)
 133                seq_printf(m, ",uid=%u", root_inode->i_uid);
 134        if (root_inode->i_gid != 0)
 135                seq_printf(m, ",gid=%u", root_inode->i_gid);
 136        seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 137        seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 138        seq_printf(m, ",minproto=%d", sbi->min_proto);
 139        seq_printf(m, ",maxproto=%d", sbi->max_proto);
 140
 141        if (autofs_type_offset(sbi->type))
 142                seq_printf(m, ",offset");
 143        else if (autofs_type_direct(sbi->type))
 144                seq_printf(m, ",direct");
 145        else
 146                seq_printf(m, ",indirect");
 147
 148        return 0;
 149}
 150
 151static const struct super_operations autofs4_sops = {
 152        .statfs         = simple_statfs,
 153        .show_options   = autofs4_show_options,
 154};
 155
 156enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 157        Opt_indirect, Opt_direct, Opt_offset};
 158
 159static const match_table_t tokens = {
 160        {Opt_fd, "fd=%u"},
 161        {Opt_uid, "uid=%u"},
 162        {Opt_gid, "gid=%u"},
 163        {Opt_pgrp, "pgrp=%u"},
 164        {Opt_minproto, "minproto=%u"},
 165        {Opt_maxproto, "maxproto=%u"},
 166        {Opt_indirect, "indirect"},
 167        {Opt_direct, "direct"},
 168        {Opt_offset, "offset"},
 169        {Opt_err, NULL}
 170};
 171
 172static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 173                pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 174{
 175        char *p;
 176        substring_t args[MAX_OPT_ARGS];
 177        int option;
 178
 179        *uid = current_uid();
 180        *gid = current_gid();
 181        *pgrp = task_pgrp_nr(current);
 182
 183        *minproto = AUTOFS_MIN_PROTO_VERSION;
 184        *maxproto = AUTOFS_MAX_PROTO_VERSION;
 185
 186        *pipefd = -1;
 187
 188        if (!options)
 189                return 1;
 190
 191        while ((p = strsep(&options, ",")) != NULL) {
 192                int token;
 193                if (!*p)
 194                        continue;
 195
 196                token = match_token(p, tokens, args);
 197                switch (token) {
 198                case Opt_fd:
 199                        if (match_int(args, pipefd))
 200                                return 1;
 201                        break;
 202                case Opt_uid:
 203                        if (match_int(args, &option))
 204                                return 1;
 205                        *uid = option;
 206                        break;
 207                case Opt_gid:
 208                        if (match_int(args, &option))
 209                                return 1;
 210                        *gid = option;
 211                        break;
 212                case Opt_pgrp:
 213                        if (match_int(args, &option))
 214                                return 1;
 215                        *pgrp = option;
 216                        break;
 217                case Opt_minproto:
 218                        if (match_int(args, &option))
 219                                return 1;
 220                        *minproto = option;
 221                        break;
 222                case Opt_maxproto:
 223                        if (match_int(args, &option))
 224                                return 1;
 225                        *maxproto = option;
 226                        break;
 227                case Opt_indirect:
 228                        set_autofs_type_indirect(type);
 229                        break;
 230                case Opt_direct:
 231                        set_autofs_type_direct(type);
 232                        break;
 233                case Opt_offset:
 234                        set_autofs_type_offset(type);
 235                        break;
 236                default:
 237                        return 1;
 238                }
 239        }
 240        return (*pipefd < 0);
 241}
 242
 243static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 244{
 245        struct autofs_info *ino;
 246
 247        ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 248        if (!ino)
 249                return NULL;
 250
 251        return ino;
 252}
 253
 254static const struct dentry_operations autofs4_sb_dentry_operations = {
 255        .d_release      = autofs4_dentry_release,
 256};
 257
 258int autofs4_fill_super(struct super_block *s, void *data, int silent)
 259{
 260        struct inode * root_inode;
 261        struct dentry * root;
 262        struct file * pipe;
 263        int pipefd;
 264        struct autofs_sb_info *sbi;
 265        struct autofs_info *ino;
 266
 267        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 268        if (!sbi)
 269                goto fail_unlock;
 270        DPRINTK("starting up, sbi = %p",sbi);
 271
 272        s->s_fs_info = sbi;
 273        sbi->magic = AUTOFS_SBI_MAGIC;
 274        sbi->pipefd = -1;
 275        sbi->pipe = NULL;
 276        sbi->catatonic = 1;
 277        sbi->exp_timeout = 0;
 278        sbi->oz_pgrp = task_pgrp_nr(current);
 279        sbi->sb = s;
 280        sbi->version = 0;
 281        sbi->sub_version = 0;
 282        set_autofs_type_indirect(&sbi->type);
 283        sbi->min_proto = 0;
 284        sbi->max_proto = 0;
 285        mutex_init(&sbi->wq_mutex);
 286        spin_lock_init(&sbi->fs_lock);
 287        sbi->queues = NULL;
 288        spin_lock_init(&sbi->lookup_lock);
 289        INIT_LIST_HEAD(&sbi->active_list);
 290        INIT_LIST_HEAD(&sbi->expiring_list);
 291        s->s_blocksize = 1024;
 292        s->s_blocksize_bits = 10;
 293        s->s_magic = AUTOFS_SUPER_MAGIC;
 294        s->s_op = &autofs4_sops;
 295        s->s_time_gran = 1;
 296
 297        /*
 298         * Get the root inode and dentry, but defer checking for errors.
 299         */
 300        ino = autofs4_mkroot(sbi);
 301        if (!ino)
 302                goto fail_free;
 303        root_inode = autofs4_get_inode(s, ino);
 304        if (!root_inode)
 305                goto fail_ino;
 306
 307        root = d_alloc_root(root_inode);
 308        if (!root)
 309                goto fail_iput;
 310        pipe = NULL;
 311
 312        root->d_op = &autofs4_sb_dentry_operations;
 313        root->d_fsdata = ino;
 314
 315        /* Can this call block? */
 316        if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 317                                &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 318                                &sbi->max_proto)) {
 319                printk("autofs: called with bogus options\n");
 320                goto fail_dput;
 321        }
 322
 323        root_inode->i_fop = &autofs4_root_operations;
 324        root_inode->i_op = autofs_type_trigger(sbi->type) ?
 325                        &autofs4_direct_root_inode_operations :
 326                        &autofs4_indirect_root_inode_operations;
 327
 328        /* Couldn't this be tested earlier? */
 329        if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 330            sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 331                printk("autofs: kernel does not match daemon version "
 332                       "daemon (%d, %d) kernel (%d, %d)\n",
 333                        sbi->min_proto, sbi->max_proto,
 334                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 335                goto fail_dput;
 336        }
 337
 338        /* Establish highest kernel protocol version */
 339        if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 340                sbi->version = AUTOFS_MAX_PROTO_VERSION;
 341        else
 342                sbi->version = sbi->max_proto;
 343        sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 344
 345        DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 346        pipe = fget(pipefd);
 347        
 348        if (!pipe) {
 349                printk("autofs: could not open pipe file descriptor\n");
 350                goto fail_dput;
 351        }
 352        if (!pipe->f_op || !pipe->f_op->write)
 353                goto fail_fput;
 354        sbi->pipe = pipe;
 355        sbi->pipefd = pipefd;
 356        sbi->catatonic = 0;
 357
 358        /*
 359         * Success! Install the root dentry now to indicate completion.
 360         */
 361        s->s_root = root;
 362        return 0;
 363        
 364        /*
 365         * Failure ... clean up.
 366         */
 367fail_fput:
 368        printk("autofs: pipe file descriptor does not contain proper ops\n");
 369        fput(pipe);
 370        /* fall through */
 371fail_dput:
 372        dput(root);
 373        goto fail_free;
 374fail_iput:
 375        printk("autofs: get root dentry failed\n");
 376        iput(root_inode);
 377fail_ino:
 378        kfree(ino);
 379fail_free:
 380        kfree(sbi);
 381        s->s_fs_info = NULL;
 382fail_unlock:
 383        return -EINVAL;
 384}
 385
 386struct inode *autofs4_get_inode(struct super_block *sb,
 387                                struct autofs_info *inf)
 388{
 389        struct inode *inode = new_inode(sb);
 390
 391        if (inode == NULL)
 392                return NULL;
 393
 394        inf->inode = inode;
 395        inode->i_mode = inf->mode;
 396        if (sb->s_root) {
 397                inode->i_uid = sb->s_root->d_inode->i_uid;
 398                inode->i_gid = sb->s_root->d_inode->i_gid;
 399        }
 400        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 401
 402        if (S_ISDIR(inf->mode)) {
 403                inode->i_nlink = 2;
 404                inode->i_op = &autofs4_dir_inode_operations;
 405                inode->i_fop = &autofs4_dir_operations;
 406        } else if (S_ISLNK(inf->mode)) {
 407                inode->i_size = inf->size;
 408                inode->i_op = &autofs4_symlink_inode_operations;
 409        }
 410
 411        return inode;
 412}
 413
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