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