linux/fs/jffs2/super.c
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   1/*
   2 * JFFS2 -- Journalling Flash File System, Version 2.
   3 *
   4 * Copyright © 2001-2007 Red Hat, Inc.
   5 *
   6 * Created by David Woodhouse <dwmw2@infradead.org>
   7 *
   8 * For licensing information, see the file 'LICENCE' in this directory.
   9 *
  10 */
  11
  12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14#include <linux/kernel.h>
  15#include <linux/module.h>
  16#include <linux/slab.h>
  17#include <linux/init.h>
  18#include <linux/list.h>
  19#include <linux/fs.h>
  20#include <linux/err.h>
  21#include <linux/mount.h>
  22#include <linux/parser.h>
  23#include <linux/jffs2.h>
  24#include <linux/pagemap.h>
  25#include <linux/mtd/super.h>
  26#include <linux/ctype.h>
  27#include <linux/namei.h>
  28#include <linux/seq_file.h>
  29#include <linux/exportfs.h>
  30#include "compr.h"
  31#include "nodelist.h"
  32
  33static void jffs2_put_super(struct super_block *);
  34
  35static struct kmem_cache *jffs2_inode_cachep;
  36
  37static struct inode *jffs2_alloc_inode(struct super_block *sb)
  38{
  39        struct jffs2_inode_info *f;
  40
  41        f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
  42        if (!f)
  43                return NULL;
  44        return &f->vfs_inode;
  45}
  46
  47static void jffs2_i_callback(struct rcu_head *head)
  48{
  49        struct inode *inode = container_of(head, struct inode, i_rcu);
  50        kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  51}
  52
  53static void jffs2_destroy_inode(struct inode *inode)
  54{
  55        call_rcu(&inode->i_rcu, jffs2_i_callback);
  56}
  57
  58static void jffs2_i_init_once(void *foo)
  59{
  60        struct jffs2_inode_info *f = foo;
  61
  62        mutex_init(&f->sem);
  63        inode_init_once(&f->vfs_inode);
  64}
  65
  66static const char *jffs2_compr_name(unsigned int compr)
  67{
  68        switch (compr) {
  69        case JFFS2_COMPR_MODE_NONE:
  70                return "none";
  71#ifdef CONFIG_JFFS2_LZO
  72        case JFFS2_COMPR_MODE_FORCELZO:
  73                return "lzo";
  74#endif
  75#ifdef CONFIG_JFFS2_ZLIB
  76        case JFFS2_COMPR_MODE_FORCEZLIB:
  77                return "zlib";
  78#endif
  79        default:
  80                /* should never happen; programmer error */
  81                WARN_ON(1);
  82                return "";
  83        }
  84}
  85
  86static int jffs2_show_options(struct seq_file *s, struct dentry *root)
  87{
  88        struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
  89        struct jffs2_mount_opts *opts = &c->mount_opts;
  90
  91        if (opts->override_compr)
  92                seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
  93        if (opts->rp_size)
  94                seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
  95
  96        return 0;
  97}
  98
  99static int jffs2_sync_fs(struct super_block *sb, int wait)
 100{
 101        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 102
 103#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 104        cancel_delayed_work_sync(&c->wbuf_dwork);
 105#endif
 106
 107        mutex_lock(&c->alloc_sem);
 108        jffs2_flush_wbuf_pad(c);
 109        mutex_unlock(&c->alloc_sem);
 110        return 0;
 111}
 112
 113static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 114                                         uint32_t generation)
 115{
 116        /* We don't care about i_generation. We'll destroy the flash
 117           before we start re-using inode numbers anyway. And even
 118           if that wasn't true, we'd have other problems...*/
 119        return jffs2_iget(sb, ino);
 120}
 121
 122static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 123                                         int fh_len, int fh_type)
 124{
 125        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 126                                    jffs2_nfs_get_inode);
 127}
 128
 129static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 130                                         int fh_len, int fh_type)
 131{
 132        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 133                                    jffs2_nfs_get_inode);
 134}
 135
 136static struct dentry *jffs2_get_parent(struct dentry *child)
 137{
 138        struct jffs2_inode_info *f;
 139        uint32_t pino;
 140
 141        BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 142
 143        f = JFFS2_INODE_INFO(child->d_inode);
 144
 145        pino = f->inocache->pino_nlink;
 146
 147        JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 148                    f->inocache->ino, pino);
 149
 150        return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 151}
 152
 153static const struct export_operations jffs2_export_ops = {
 154        .get_parent = jffs2_get_parent,
 155        .fh_to_dentry = jffs2_fh_to_dentry,
 156        .fh_to_parent = jffs2_fh_to_parent,
 157};
 158
 159/*
 160 * JFFS2 mount options.
 161 *
 162 * Opt_override_compr: override default compressor
 163 * Opt_rp_size: size of reserved pool in KiB
 164 * Opt_err: just end of array marker
 165 */
 166enum {
 167        Opt_override_compr,
 168        Opt_rp_size,
 169        Opt_err,
 170};
 171
 172static const match_table_t tokens = {
 173        {Opt_override_compr, "compr=%s"},
 174        {Opt_rp_size, "rp_size=%u"},
 175        {Opt_err, NULL},
 176};
 177
 178static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 179{
 180        substring_t args[MAX_OPT_ARGS];
 181        char *p, *name;
 182        unsigned int opt;
 183
 184        if (!data)
 185                return 0;
 186
 187        while ((p = strsep(&data, ","))) {
 188                int token;
 189
 190                if (!*p)
 191                        continue;
 192
 193                token = match_token(p, tokens, args);
 194                switch (token) {
 195                case Opt_override_compr:
 196                        name = match_strdup(&args[0]);
 197
 198                        if (!name)
 199                                return -ENOMEM;
 200                        if (!strcmp(name, "none"))
 201                                c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 202#ifdef CONFIG_JFFS2_LZO
 203                        else if (!strcmp(name, "lzo"))
 204                                c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 205#endif
 206#ifdef CONFIG_JFFS2_ZLIB
 207                        else if (!strcmp(name, "zlib"))
 208                                c->mount_opts.compr =
 209                                                JFFS2_COMPR_MODE_FORCEZLIB;
 210#endif
 211                        else {
 212                                pr_err("Error: unknown compressor \"%s\"\n",
 213                                       name);
 214                                kfree(name);
 215                                return -EINVAL;
 216                        }
 217                        kfree(name);
 218                        c->mount_opts.override_compr = true;
 219                        break;
 220                case Opt_rp_size:
 221                        if (match_int(&args[0], &opt))
 222                                return -EINVAL;
 223                        opt *= 1024;
 224                        if (opt > c->mtd->size) {
 225                                pr_warn("Too large reserve pool specified, max "
 226                                        "is %llu KB\n", c->mtd->size / 1024);
 227                                return -EINVAL;
 228                        }
 229                        c->mount_opts.rp_size = opt;
 230                        break;
 231                default:
 232                        pr_err("Error: unrecognized mount option '%s' or missing value\n",
 233                               p);
 234                        return -EINVAL;
 235                }
 236        }
 237
 238        return 0;
 239}
 240
 241static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 242{
 243        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 244        int err;
 245
 246        err = jffs2_parse_options(c, data);
 247        if (err)
 248                return -EINVAL;
 249
 250        return jffs2_do_remount_fs(sb, flags, data);
 251}
 252
 253static const struct super_operations jffs2_super_operations =
 254{
 255        .alloc_inode =  jffs2_alloc_inode,
 256        .destroy_inode =jffs2_destroy_inode,
 257        .put_super =    jffs2_put_super,
 258        .statfs =       jffs2_statfs,
 259        .remount_fs =   jffs2_remount_fs,
 260        .evict_inode =  jffs2_evict_inode,
 261        .dirty_inode =  jffs2_dirty_inode,
 262        .show_options = jffs2_show_options,
 263        .sync_fs =      jffs2_sync_fs,
 264};
 265
 266/*
 267 * fill in the superblock
 268 */
 269static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 270{
 271        struct jffs2_sb_info *c;
 272        int ret;
 273
 274        jffs2_dbg(1, "jffs2_get_sb_mtd():"
 275                  " New superblock for device %d (\"%s\")\n",
 276                  sb->s_mtd->index, sb->s_mtd->name);
 277
 278        c = kzalloc(sizeof(*c), GFP_KERNEL);
 279        if (!c)
 280                return -ENOMEM;
 281
 282        c->mtd = sb->s_mtd;
 283        c->os_priv = sb;
 284        sb->s_fs_info = c;
 285
 286        ret = jffs2_parse_options(c, data);
 287        if (ret) {
 288                kfree(c);
 289                return -EINVAL;
 290        }
 291
 292        /* Initialize JFFS2 superblock locks, the further initialization will
 293         * be done later */
 294        mutex_init(&c->alloc_sem);
 295        mutex_init(&c->erase_free_sem);
 296        init_waitqueue_head(&c->erase_wait);
 297        init_waitqueue_head(&c->inocache_wq);
 298        spin_lock_init(&c->erase_completion_lock);
 299        spin_lock_init(&c->inocache_lock);
 300
 301        sb->s_op = &jffs2_super_operations;
 302        sb->s_export_op = &jffs2_export_ops;
 303        sb->s_flags = sb->s_flags | MS_NOATIME;
 304        sb->s_xattr = jffs2_xattr_handlers;
 305#ifdef CONFIG_JFFS2_FS_POSIX_ACL
 306        sb->s_flags |= MS_POSIXACL;
 307#endif
 308        ret = jffs2_do_fill_super(sb, data, silent);
 309        return ret;
 310}
 311
 312static struct dentry *jffs2_mount(struct file_system_type *fs_type,
 313                        int flags, const char *dev_name,
 314                        void *data)
 315{
 316        return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
 317}
 318
 319static void jffs2_put_super (struct super_block *sb)
 320{
 321        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 322
 323        jffs2_dbg(2, "%s()\n", __func__);
 324
 325        mutex_lock(&c->alloc_sem);
 326        jffs2_flush_wbuf_pad(c);
 327        mutex_unlock(&c->alloc_sem);
 328
 329        jffs2_sum_exit(c);
 330
 331        jffs2_free_ino_caches(c);
 332        jffs2_free_raw_node_refs(c);
 333        if (jffs2_blocks_use_vmalloc(c))
 334                vfree(c->blocks);
 335        else
 336                kfree(c->blocks);
 337        jffs2_flash_cleanup(c);
 338        kfree(c->inocache_list);
 339        jffs2_clear_xattr_subsystem(c);
 340        mtd_sync(c->mtd);
 341        jffs2_dbg(1, "%s(): returning\n", __func__);
 342}
 343
 344static void jffs2_kill_sb(struct super_block *sb)
 345{
 346        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 347        if (!(sb->s_flags & MS_RDONLY))
 348                jffs2_stop_garbage_collect_thread(c);
 349        kill_mtd_super(sb);
 350        kfree(c);
 351}
 352
 353static struct file_system_type jffs2_fs_type = {
 354        .owner =        THIS_MODULE,
 355        .name =         "jffs2",
 356        .mount =        jffs2_mount,
 357        .kill_sb =      jffs2_kill_sb,
 358};
 359
 360static int __init init_jffs2_fs(void)
 361{
 362        int ret;
 363
 364        /* Paranoia checks for on-medium structures. If we ask GCC
 365           to pack them with __attribute__((packed)) then it _also_
 366           assumes that they're not aligned -- so it emits crappy
 367           code on some architectures. Ideally we want an attribute
 368           which means just 'no padding', without the alignment
 369           thing. But GCC doesn't have that -- we have to just
 370           hope the structs are the right sizes, instead. */
 371        BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 372        BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 373        BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 374        BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 375
 376        pr_info("version 2.2."
 377#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 378               " (NAND)"
 379#endif
 380#ifdef CONFIG_JFFS2_SUMMARY
 381               " (SUMMARY) "
 382#endif
 383               " © 2001-2006 Red Hat, Inc.\n");
 384
 385        jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 386                                             sizeof(struct jffs2_inode_info),
 387                                             0, (SLAB_RECLAIM_ACCOUNT|
 388                                                SLAB_MEM_SPREAD),
 389                                             jffs2_i_init_once);
 390        if (!jffs2_inode_cachep) {
 391                pr_err("error: Failed to initialise inode cache\n");
 392                return -ENOMEM;
 393        }
 394        ret = jffs2_compressors_init();
 395        if (ret) {
 396                pr_err("error: Failed to initialise compressors\n");
 397                goto out;
 398        }
 399        ret = jffs2_create_slab_caches();
 400        if (ret) {
 401                pr_err("error: Failed to initialise slab caches\n");
 402                goto out_compressors;
 403        }
 404        ret = register_filesystem(&jffs2_fs_type);
 405        if (ret) {
 406                pr_err("error: Failed to register filesystem\n");
 407                goto out_slab;
 408        }
 409        return 0;
 410
 411 out_slab:
 412        jffs2_destroy_slab_caches();
 413 out_compressors:
 414        jffs2_compressors_exit();
 415 out:
 416        kmem_cache_destroy(jffs2_inode_cachep);
 417        return ret;
 418}
 419
 420static void __exit exit_jffs2_fs(void)
 421{
 422        unregister_filesystem(&jffs2_fs_type);
 423        jffs2_destroy_slab_caches();
 424        jffs2_compressors_exit();
 425
 426        /*
 427         * Make sure all delayed rcu free inodes are flushed before we
 428         * destroy cache.
 429         */
 430        rcu_barrier();
 431        kmem_cache_destroy(jffs2_inode_cachep);
 432}
 433
 434module_init(init_jffs2_fs);
 435module_exit(exit_jffs2_fs);
 436
 437MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 438MODULE_AUTHOR("Red Hat, Inc.");
 439MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 440                       // the sake of this tag. It's Free Software.
 441
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