fs/jffs2/super.c

   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
  33 static void jffs2_put_super(struct super_block *);
  34
  35 static struct kmem_cache *jffs2_inode_cachep;
  36
  37 static 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
  47 static 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
  53 static void jffs2_destroy_inode(struct inode *inode)
  54 {
  55         call_rcu(&inode->i_rcu, jffs2_i_callback);
  56 }
  57
  58 static 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
  66 static void jffs2_write_super(struct super_block *sb)
  67 {
  68         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  69
  70         sb->s_dirt = 0;
  71
  72         if (!(sb->s_flags & MS_RDONLY)) {
  73                 jffs2_dbg(1, "%s()\n", __func__);
  74                 jffs2_flush_wbuf_gc(c, 0);
  75         }
  76 }
  77
  78 static const char *jffs2_compr_name(unsigned int compr)
  79 {
  80         switch (compr) {
  81         case JFFS2_COMPR_MODE_NONE:
  82                 return "none";
  83 #ifdef CONFIG_JFFS2_LZO
  84         case JFFS2_COMPR_MODE_FORCELZO:
  85                 return "lzo";
  86 #endif
  87 #ifdef CONFIG_JFFS2_ZLIB
  88         case JFFS2_COMPR_MODE_FORCEZLIB:
  89                 return "zlib";
  90 #endif
  91         default:
  92                 /* should never happen; programmer error */
  93                 WARN_ON(1);
  94                 return "";
  95         }
  96 }
  97
  98 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
  99 {
 100         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
 101         struct jffs2_mount_opts *opts = &c->mount_opts;
 102
 103         if (opts->override_compr)
 104                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
 105         if (opts->rp_size)
 106                 seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
 107
 108         return 0;
 109 }
 110
 111 static int jffs2_sync_fs(struct super_block *sb, int wait)
 112 {
 113         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 114
 115         jffs2_write_super(sb);
 116
 117         mutex_lock(&c->alloc_sem);
 118         jffs2_flush_wbuf_pad(c);
 119         mutex_unlock(&c->alloc_sem);
 120         return 0;
 121 }
 122
 123 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 124                                          uint32_t generation)
 125 {
 126         /* We don't care about i_generation. We'll destroy the flash
 127            before we start re-using inode numbers anyway. And even
 128            if that wasn't true, we'd have other problems...*/
 129         return jffs2_iget(sb, ino);
 130 }
 131
 132 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 133                                          int fh_len, int fh_type)
 134 {
 135         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 136                                     jffs2_nfs_get_inode);
 137 }
 138
 139 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 140                                          int fh_len, int fh_type)
 141 {
 142         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 143                                     jffs2_nfs_get_inode);
 144 }
 145
 146 static struct dentry *jffs2_get_parent(struct dentry *child)
 147 {
 148         struct jffs2_inode_info *f;
 149         uint32_t pino;
 150
 151         BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 152
 153         f = JFFS2_INODE_INFO(child->d_inode);
 154
 155         pino = f->inocache->pino_nlink;
 156
 157         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 158                     f->inocache->ino, pino);
 159
 160         return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 161 }
 162
 163 static const struct export_operations jffs2_export_ops = {
 164         .get_parent = jffs2_get_parent,
 165         .fh_to_dentry = jffs2_fh_to_dentry,
 166         .fh_to_parent = jffs2_fh_to_parent,
 167 };
 168
 169 /*
 170  * JFFS2 mount options.
 171  *
 172  * Opt_override_compr: override default compressor
 173  * Opt_rp_size: size of reserved pool in KiB
 174  * Opt_err: just end of array marker
 175  */
 176 enum {
 177         Opt_override_compr,
 178         Opt_rp_size,
 179         Opt_err,
 180 };
 181
 182 static const match_table_t tokens = {
 183         {Opt_override_compr, "compr=%s"},
 184         {Opt_rp_size, "rp_size=%u"},
 185         {Opt_err, NULL},
 186 };
 187
 188 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 189 {
 190         substring_t args[MAX_OPT_ARGS];
 191         char *p, *name;
 192         unsigned int opt;
 193
 194         if (!data)
 195                 return 0;
 196
 197         while ((p = strsep(&data, ","))) {
 198                 int token;
 199
 200                 if (!*p)
 201                         continue;
 202
 203                 token = match_token(p, tokens, args);
 204                 switch (token) {
 205                 case Opt_override_compr:
 206                         name = match_strdup(&args[0]);
 207
 208                         if (!name)
 209                                 return -ENOMEM;
 210                         if (!strcmp(name, "none"))
 211                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 212 #ifdef CONFIG_JFFS2_LZO
 213                         else if (!strcmp(name, "lzo"))
 214                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 215 #endif
 216 #ifdef CONFIG_JFFS2_ZLIB
 217                         else if (!strcmp(name, "zlib"))
 218                                 c->mount_opts.compr =
 219                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 220 #endif
 221                         else {
 222                                 pr_err("Error: unknown compressor \"%s\"\n",
 223                                        name);
 224                                 kfree(name);
 225                                 return -EINVAL;
 226                         }
 227                         kfree(name);
 228                         c->mount_opts.override_compr = true;
 229                         break;
 230                 case Opt_rp_size:
 231                         if (match_int(&args[0], &opt))
 232                                 return -EINVAL;
 233                         opt *= 1024;
 234                         if (opt > c->mtd->size) {
 235                                 pr_warn("Too large reserve pool specified, max "
 236                                         "is %llu KB\n", c->mtd->size / 1024);
 237                                 return -EINVAL;
 238                         }
 239                         c->mount_opts.rp_size = opt;
 240                         break;
 241                 default:
 242                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
 243                                p);
 244                         return -EINVAL;
 245                 }
 246         }
 247
 248         return 0;
 249 }
 250
 251 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 252 {
 253         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 254         int err;
 255
 256         err = jffs2_parse_options(c, data);
 257         if (err)
 258                 return -EINVAL;
 259
 260         return jffs2_do_remount_fs(sb, flags, data);
 261 }
 262
 263 static const struct super_operations jffs2_super_operations =
 264 {
 265         .alloc_inode =  jffs2_alloc_inode,
 266         .destroy_inode =jffs2_destroy_inode,
 267         .put_super =    jffs2_put_super,
 268         .write_super =  jffs2_write_super,
 269         .statfs =       jffs2_statfs,
 270         .remount_fs =   jffs2_remount_fs,
 271         .evict_inode =  jffs2_evict_inode,
 272         .dirty_inode =  jffs2_dirty_inode,
 273         .show_options = jffs2_show_options,
 274         .sync_fs =      jffs2_sync_fs,
 275 };
 276
 277 /*
 278  * fill in the superblock
 279  */
 280 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 281 {
 282         struct jffs2_sb_info *c;
 283         int ret;
 284
 285         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 286                   " New superblock for device %d (\"%s\")\n",
 287                   sb->s_mtd->index, sb->s_mtd->name);
 288
 289         c = kzalloc(sizeof(*c), GFP_KERNEL);
 290         if (!c)
 291                 return -ENOMEM;
 292
 293         c->mtd = sb->s_mtd;
 294         c->os_priv = sb;
 295         sb->s_fs_info = c;
 296
 297         ret = jffs2_parse_options(c, data);
 298         if (ret) {
 299                 kfree(c);
 300                 return -EINVAL;
 301         }
 302
 303         /* Initialize JFFS2 superblock locks, the further initialization will
 304          * be done later */
 305         mutex_init(&c->alloc_sem);
 306         mutex_init(&c->erase_free_sem);
 307         init_waitqueue_head(&c->erase_wait);
 308         init_waitqueue_head(&c->inocache_wq);
 309         spin_lock_init(&c->erase_completion_lock);
 310         spin_lock_init(&c->inocache_lock);
 311
 312         sb->s_op = &jffs2_super_operations;
 313         sb->s_export_op = &jffs2_export_ops;
 314         sb->s_flags = sb->s_flags | MS_NOATIME;
 315         sb->s_xattr = jffs2_xattr_handlers;
 316 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 317         sb->s_flags |= MS_POSIXACL;
 318 #endif
 319         ret = jffs2_do_fill_super(sb, data, silent);
 320         return ret;
 321 }
 322
 323 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
 324                         int flags, const char *dev_name,
 325                         void *data)
 326 {
 327         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
 328 }
 329
 330 static void jffs2_put_super (struct super_block *sb)
 331 {
 332         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 333
 334         jffs2_dbg(2, "%s()\n", __func__);
 335
 336         mutex_lock(&c->alloc_sem);
 337         jffs2_flush_wbuf_pad(c);
 338         mutex_unlock(&c->alloc_sem);
 339
 340         jffs2_sum_exit(c);
 341
 342         jffs2_free_ino_caches(c);
 343         jffs2_free_raw_node_refs(c);
 344         if (jffs2_blocks_use_vmalloc(c))
 345                 vfree(c->blocks);
 346         else
 347                 kfree(c->blocks);
 348         jffs2_flash_cleanup(c);
 349         kfree(c->inocache_list);
 350         jffs2_clear_xattr_subsystem(c);
 351         mtd_sync(c->mtd);
 352         jffs2_dbg(1, "%s(): returning\n", __func__);
 353 }
 354
 355 static void jffs2_kill_sb(struct super_block *sb)
 356 {
 357         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 358         if (!(sb->s_flags & MS_RDONLY))
 359                 jffs2_stop_garbage_collect_thread(c);
 360         kill_mtd_super(sb);
 361         kfree(c);
 362 }
 363
 364 static struct file_system_type jffs2_fs_type = {
 365         .owner =        THIS_MODULE,
 366         .name =         "jffs2",
 367         .mount =        jffs2_mount,
 368         .kill_sb =      jffs2_kill_sb,
 369 };
 370
 371 static int __init init_jffs2_fs(void)
 372 {
 373         int ret;
 374
 375         /* Paranoia checks for on-medium structures. If we ask GCC
 376            to pack them with __attribute__((packed)) then it _also_
 377            assumes that they're not aligned -- so it emits crappy
 378            code on some architectures. Ideally we want an attribute
 379            which means just 'no padding', without the alignment
 380            thing. But GCC doesn't have that -- we have to just
 381            hope the structs are the right sizes, instead. */
 382         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 383         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 384         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 385         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 386
 387         pr_info("version 2.2."
 388 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 389                " (NAND)"
 390 #endif
 391 #ifdef CONFIG_JFFS2_SUMMARY
 392                " (SUMMARY) "
 393 #endif
 394                " © 2001-2006 Red Hat, Inc.\n");
 395
 396         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 397                                              sizeof(struct jffs2_inode_info),
 398                                              0, (SLAB_RECLAIM_ACCOUNT|
 399                                                 SLAB_MEM_SPREAD),
 400                                              jffs2_i_init_once);
 401         if (!jffs2_inode_cachep) {
 402                 pr_err("error: Failed to initialise inode cache\n");
 403                 return -ENOMEM;
 404         }
 405         ret = jffs2_compressors_init();
 406         if (ret) {
 407                 pr_err("error: Failed to initialise compressors\n");
 408                 goto out;
 409         }
 410         ret = jffs2_create_slab_caches();
 411         if (ret) {
 412                 pr_err("error: Failed to initialise slab caches\n");
 413                 goto out_compressors;
 414         }
 415         ret = register_filesystem(&jffs2_fs_type);
 416         if (ret) {
 417                 pr_err("error: Failed to register filesystem\n");
 418                 goto out_slab;
 419         }
 420         return 0;
 421
 422  out_slab:
 423         jffs2_destroy_slab_caches();
 424  out_compressors:
 425         jffs2_compressors_exit();
 426  out:
 427         kmem_cache_destroy(jffs2_inode_cachep);
 428         return ret;
 429 }
 430
 431 static void __exit exit_jffs2_fs(void)
 432 {
 433         unregister_filesystem(&jffs2_fs_type);
 434         jffs2_destroy_slab_caches();
 435         jffs2_compressors_exit();
 436         kmem_cache_destroy(jffs2_inode_cachep);
 437 }
 438
 439 module_init(init_jffs2_fs);
 440 module_exit(exit_jffs2_fs);
 441
 442 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 443 MODULE_AUTHOR("Red Hat, Inc.");
 444 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 445                        // the sake of this tag. It's Free Software.