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                INIT_LIST_HEAD(&ino->expiring);
  53                atomic_set(&ino->count, 0);
  54        }
  55
  56        ino->uid = 0;
  57        ino->gid = 0;
  58        ino->mode = mode;
  59        ino->last_used = jiffies;
  60
  61        ino->sbi = sbi;
  62
  63        if (reinit && ino->free)
  64                (ino->free)(ino);
  65
  66        memset(&ino->u, 0, sizeof(ino->u));
  67
  68        ino->free = NULL;
  69
  70        if (S_ISLNK(mode))
  71                ino->free = ino_lnkfree;
  72
  73        return ino;
  74}
  75
  76void autofs4_free_ino(struct autofs_info *ino)
  77{
  78        struct autofs_info *p_ino;
  79
  80        if (ino->dentry) {
  81                ino->dentry->d_fsdata = NULL;
  82                if (ino->dentry->d_inode) {
  83                        struct dentry *parent = ino->dentry->d_parent;
  84                        if (atomic_dec_and_test(&ino->count)) {
  85                                p_ino = autofs4_dentry_ino(parent);
  86                                if (p_ino && parent != ino->dentry)
  87                                        atomic_dec(&p_ino->count);
  88                        }
  89                        dput(ino->dentry);
  90                }
  91                ino->dentry = NULL;
  92        }
  93        if (ino->free)
  94                (ino->free)(ino);
  95        kfree(ino);
  96}
  97
  98/*
  99 * Deal with the infamous "Busy inodes after umount ..." message.
 100 *
 101 * Clean up the dentry tree. This happens with autofs if the user
 102 * space program goes away due to a SIGKILL, SIGSEGV etc.
 103 */
 104static void autofs4_force_release(struct autofs_sb_info *sbi)
 105{
 106        struct dentry *this_parent = sbi->sb->s_root;
 107        struct list_head *next;
 108
 109        if (!sbi->sb->s_root)
 110                return;
 111
 112        spin_lock(&dcache_lock);
 113repeat:
 114        next = this_parent->d_subdirs.next;
 115resume:
 116        while (next != &this_parent->d_subdirs) {
 117                struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 118
 119                /* Negative dentry - don`t care */
 120                if (!simple_positive(dentry)) {
 121                        next = next->next;
 122                        continue;
 123                }
 124
 125                if (!list_empty(&dentry->d_subdirs)) {
 126                        this_parent = dentry;
 127                        goto repeat;
 128                }
 129
 130                next = next->next;
 131                spin_unlock(&dcache_lock);
 132
 133                DPRINTK("dentry %p %.*s",
 134                        dentry, (int)dentry->d_name.len, dentry->d_name.name);
 135
 136                dput(dentry);
 137                spin_lock(&dcache_lock);
 138        }
 139
 140        if (this_parent != sbi->sb->s_root) {
 141                struct dentry *dentry = this_parent;
 142
 143                next = this_parent->d_u.d_child.next;
 144                this_parent = this_parent->d_parent;
 145                spin_unlock(&dcache_lock);
 146                DPRINTK("parent dentry %p %.*s",
 147                        dentry, (int)dentry->d_name.len, dentry->d_name.name);
 148                dput(dentry);
 149                spin_lock(&dcache_lock);
 150                goto resume;
 151        }
 152        spin_unlock(&dcache_lock);
 153}
 154
 155void autofs4_kill_sb(struct super_block *sb)
 156{
 157        struct autofs_sb_info *sbi = autofs4_sbi(sb);
 158
 159        /*
 160         * In the event of a failure in get_sb_nodev the superblock
 161         * info is not present so nothing else has been setup, so
 162         * just call kill_anon_super when we are called from
 163         * deactivate_super.
 164         */
 165        if (!sbi)
 166                goto out_kill_sb;
 167
 168        /* Free wait queues, close pipe */
 169        autofs4_catatonic_mode(sbi);
 170
 171        /* Clean up and release dangling references */
 172        autofs4_force_release(sbi);
 173
 174        sb->s_fs_info = NULL;
 175        kfree(sbi);
 176
 177out_kill_sb:
 178        DPRINTK("shutting down");
 179        kill_anon_super(sb);
 180}
 181
 182static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
 183{
 184        struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
 185        struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
 186
 187        if (!sbi)
 188                return 0;
 189
 190        seq_printf(m, ",fd=%d", sbi->pipefd);
 191        if (root_inode->i_uid != 0)
 192                seq_printf(m, ",uid=%u", root_inode->i_uid);
 193        if (root_inode->i_gid != 0)
 194                seq_printf(m, ",gid=%u", root_inode->i_gid);
 195        seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
 196        seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
 197        seq_printf(m, ",minproto=%d", sbi->min_proto);
 198        seq_printf(m, ",maxproto=%d", sbi->max_proto);
 199
 200        if (autofs_type_offset(sbi->type))
 201                seq_printf(m, ",offset");
 202        else if (autofs_type_direct(sbi->type))
 203                seq_printf(m, ",direct");
 204        else
 205                seq_printf(m, ",indirect");
 206
 207        return 0;
 208}
 209
 210static const struct super_operations autofs4_sops = {
 211        .statfs         = simple_statfs,
 212        .show_options   = autofs4_show_options,
 213};
 214
 215enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
 216        Opt_indirect, Opt_direct, Opt_offset};
 217
 218static const match_table_t tokens = {
 219        {Opt_fd, "fd=%u"},
 220        {Opt_uid, "uid=%u"},
 221        {Opt_gid, "gid=%u"},
 222        {Opt_pgrp, "pgrp=%u"},
 223        {Opt_minproto, "minproto=%u"},
 224        {Opt_maxproto, "maxproto=%u"},
 225        {Opt_indirect, "indirect"},
 226        {Opt_direct, "direct"},
 227        {Opt_offset, "offset"},
 228        {Opt_err, NULL}
 229};
 230
 231static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 232                pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
 233{
 234        char *p;
 235        substring_t args[MAX_OPT_ARGS];
 236        int option;
 237
 238        *uid = current_uid();
 239        *gid = current_gid();
 240        *pgrp = task_pgrp_nr(current);
 241
 242        *minproto = AUTOFS_MIN_PROTO_VERSION;
 243        *maxproto = AUTOFS_MAX_PROTO_VERSION;
 244
 245        *pipefd = -1;
 246
 247        if (!options)
 248                return 1;
 249
 250        while ((p = strsep(&options, ",")) != NULL) {
 251                int token;
 252                if (!*p)
 253                        continue;
 254
 255                token = match_token(p, tokens, args);
 256                switch (token) {
 257                case Opt_fd:
 258                        if (match_int(args, pipefd))
 259                                return 1;
 260                        break;
 261                case Opt_uid:
 262                        if (match_int(args, &option))
 263                                return 1;
 264                        *uid = option;
 265                        break;
 266                case Opt_gid:
 267                        if (match_int(args, &option))
 268                                return 1;
 269                        *gid = option;
 270                        break;
 271                case Opt_pgrp:
 272                        if (match_int(args, &option))
 273                                return 1;
 274                        *pgrp = option;
 275                        break;
 276                case Opt_minproto:
 277                        if (match_int(args, &option))
 278                                return 1;
 279                        *minproto = option;
 280                        break;
 281                case Opt_maxproto:
 282                        if (match_int(args, &option))
 283                                return 1;
 284                        *maxproto = option;
 285                        break;
 286                case Opt_indirect:
 287                        set_autofs_type_indirect(type);
 288                        break;
 289                case Opt_direct:
 290                        set_autofs_type_direct(type);
 291                        break;
 292                case Opt_offset:
 293                        set_autofs_type_offset(type);
 294                        break;
 295                default:
 296                        return 1;
 297                }
 298        }
 299        return (*pipefd < 0);
 300}
 301
 302static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 303{
 304        struct autofs_info *ino;
 305
 306        ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
 307        if (!ino)
 308                return NULL;
 309
 310        return ino;
 311}
 312
 313static const struct dentry_operations autofs4_sb_dentry_operations = {
 314        .d_release      = autofs4_dentry_release,
 315};
 316
 317int autofs4_fill_super(struct super_block *s, void *data, int silent)
 318{
 319        struct inode * root_inode;
 320        struct dentry * root;
 321        struct file * pipe;
 322        int pipefd;
 323        struct autofs_sb_info *sbi;
 324        struct autofs_info *ino;
 325
 326        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 327        if (!sbi)
 328                goto fail_unlock;
 329        DPRINTK("starting up, sbi = %p",sbi);
 330
 331        s->s_fs_info = sbi;
 332        sbi->magic = AUTOFS_SBI_MAGIC;
 333        sbi->pipefd = -1;
 334        sbi->pipe = NULL;
 335        sbi->catatonic = 1;
 336        sbi->exp_timeout = 0;
 337        sbi->oz_pgrp = task_pgrp_nr(current);
 338        sbi->sb = s;
 339        sbi->version = 0;
 340        sbi->sub_version = 0;
 341        set_autofs_type_indirect(&sbi->type);
 342        sbi->min_proto = 0;
 343        sbi->max_proto = 0;
 344        mutex_init(&sbi->wq_mutex);
 345        spin_lock_init(&sbi->fs_lock);
 346        sbi->queues = NULL;
 347        spin_lock_init(&sbi->lookup_lock);
 348        INIT_LIST_HEAD(&sbi->active_list);
 349        INIT_LIST_HEAD(&sbi->expiring_list);
 350        s->s_blocksize = 1024;
 351        s->s_blocksize_bits = 10;
 352        s->s_magic = AUTOFS_SUPER_MAGIC;
 353        s->s_op = &autofs4_sops;
 354        s->s_time_gran = 1;
 355
 356        /*
 357         * Get the root inode and dentry, but defer checking for errors.
 358         */
 359        ino = autofs4_mkroot(sbi);
 360        if (!ino)
 361                goto fail_free;
 362        root_inode = autofs4_get_inode(s, ino);
 363        if (!root_inode)
 364                goto fail_ino;
 365
 366        root = d_alloc_root(root_inode);
 367        if (!root)
 368                goto fail_iput;
 369        pipe = NULL;
 370
 371        root->d_op = &autofs4_sb_dentry_operations;
 372        root->d_fsdata = ino;
 373
 374        /* Can this call block? */
 375        if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
 376                                &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
 377                                &sbi->max_proto)) {
 378                printk("autofs: called with bogus options\n");
 379                goto fail_dput;
 380        }
 381
 382        root_inode->i_fop = &autofs4_root_operations;
 383        root_inode->i_op = autofs_type_trigger(sbi->type) ?
 384                        &autofs4_direct_root_inode_operations :
 385                        &autofs4_indirect_root_inode_operations;
 386
 387        /* Couldn't this be tested earlier? */
 388        if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
 389            sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 390                printk("autofs: kernel does not match daemon version "
 391                       "daemon (%d, %d) kernel (%d, %d)\n",
 392                        sbi->min_proto, sbi->max_proto,
 393                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 394                goto fail_dput;
 395        }
 396
 397        /* Establish highest kernel protocol version */
 398        if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
 399                sbi->version = AUTOFS_MAX_PROTO_VERSION;
 400        else
 401                sbi->version = sbi->max_proto;
 402        sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
 403
 404        DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
 405        pipe = fget(pipefd);
 406        
 407        if (!pipe) {
 408                printk("autofs: could not open pipe file descriptor\n");
 409                goto fail_dput;
 410        }
 411        if (!pipe->f_op || !pipe->f_op->write)
 412                goto fail_fput;
 413        sbi->pipe = pipe;
 414        sbi->pipefd = pipefd;
 415        sbi->catatonic = 0;
 416
 417        /*
 418         * Success! Install the root dentry now to indicate completion.
 419         */
 420        s->s_root = root;
 421        return 0;
 422        
 423        /*
 424         * Failure ... clean up.
 425         */
 426fail_fput:
 427        printk("autofs: pipe file descriptor does not contain proper ops\n");
 428        fput(pipe);
 429        /* fall through */
 430fail_dput:
 431        dput(root);
 432        goto fail_free;
 433fail_iput:
 434        printk("autofs: get root dentry failed\n");
 435        iput(root_inode);
 436fail_ino:
 437        kfree(ino);
 438fail_free:
 439        kfree(sbi);
 440        s->s_fs_info = NULL;
 441fail_unlock:
 442        return -EINVAL;
 443}
 444
 445struct inode *autofs4_get_inode(struct super_block *sb,
 446                                struct autofs_info *inf)
 447{
 448        struct inode *inode = new_inode(sb);
 449
 450        if (inode == NULL)
 451                return NULL;
 452
 453        inf->inode = inode;
 454        inode->i_mode = inf->mode;
 455        if (sb->s_root) {
 456                inode->i_uid = sb->s_root->d_inode->i_uid;
 457                inode->i_gid = sb->s_root->d_inode->i_gid;
 458        }
 459        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 460
 461        if (S_ISDIR(inf->mode)) {
 462                inode->i_nlink = 2;
 463                inode->i_op = &autofs4_dir_inode_operations;
 464                inode->i_fop = &autofs4_dir_operations;
 465        } else if (S_ISLNK(inf->mode)) {
 466                inode->i_size = inf->size;
 467                inode->i_op = &autofs4_symlink_inode_operations;
 468        }
 469
 470        return inode;
 471}
 472