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 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
  86 static 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
  99 static 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         if (jffs2_is_writebuffered(c))
 105                 cancel_delayed_work_sync(&c->wbuf_dwork);
 106 #endif
 107
 108         mutex_lock(&c->alloc_sem);
 109         jffs2_flush_wbuf_pad(c);
 110         mutex_unlock(&c->alloc_sem);
 111         return 0;
 112 }
 113
 114 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 115                                          uint32_t generation)
 116 {
 117         /* We don't care about i_generation. We'll destroy the flash
 118            before we start re-using inode numbers anyway. And even
 119            if that wasn't true, we'd have other problems...*/
 120         return jffs2_iget(sb, ino);
 121 }
 122
 123 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 124                                          int fh_len, int fh_type)
 125 {
 126         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 127                                     jffs2_nfs_get_inode);
 128 }
 129
 130 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 131                                          int fh_len, int fh_type)
 132 {
 133         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 134                                     jffs2_nfs_get_inode);
 135 }
 136
 137 static struct dentry *jffs2_get_parent(struct dentry *child)
 138 {
 139         struct jffs2_inode_info *f;
 140         uint32_t pino;
 141
 142         BUG_ON(!d_is_dir(child));
 143
 144         f = JFFS2_INODE_INFO(d_inode(child));
 145
 146         pino = f->inocache->pino_nlink;
 147
 148         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 149                     f->inocache->ino, pino);
 150
 151         return d_obtain_alias(jffs2_iget(child->d_sb, pino));
 152 }
 153
 154 static const struct export_operations jffs2_export_ops = {
 155         .get_parent = jffs2_get_parent,
 156         .fh_to_dentry = jffs2_fh_to_dentry,
 157         .fh_to_parent = jffs2_fh_to_parent,
 158 };
 159
 160 /*
 161  * JFFS2 mount options.
 162  *
 163  * Opt_override_compr: override default compressor
 164  * Opt_rp_size: size of reserved pool in KiB
 165  * Opt_err: just end of array marker
 166  */
 167 enum {
 168         Opt_override_compr,
 169         Opt_rp_size,
 170         Opt_err,
 171 };
 172
 173 static const match_table_t tokens = {
 174         {Opt_override_compr, "compr=%s"},
 175         {Opt_rp_size, "rp_size=%u"},
 176         {Opt_err, NULL},
 177 };
 178
 179 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 180 {
 181         substring_t args[MAX_OPT_ARGS];
 182         char *p, *name;
 183         unsigned int opt;
 184
 185         if (!data)
 186                 return 0;
 187
 188         while ((p = strsep(&data, ","))) {
 189                 int token;
 190
 191                 if (!*p)
 192                         continue;
 193
 194                 token = match_token(p, tokens, args);
 195                 switch (token) {
 196                 case Opt_override_compr:
 197                         name = match_strdup(&args[0]);
 198
 199                         if (!name)
 200                                 return -ENOMEM;
 201                         if (!strcmp(name, "none"))
 202                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 203 #ifdef CONFIG_JFFS2_LZO
 204                         else if (!strcmp(name, "lzo"))
 205                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 206 #endif
 207 #ifdef CONFIG_JFFS2_ZLIB
 208                         else if (!strcmp(name, "zlib"))
 209                                 c->mount_opts.compr =
 210                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 211 #endif
 212                         else {
 213                                 pr_err("Error: unknown compressor \"%s\"\n",
 214                                        name);
 215                                 kfree(name);
 216                                 return -EINVAL;
 217                         }
 218                         kfree(name);
 219                         c->mount_opts.override_compr = true;
 220                         break;
 221                 case Opt_rp_size:
 222                         if (match_int(&args[0], &opt))
 223                                 return -EINVAL;
 224                         opt *= 1024;
 225                         if (opt > c->mtd->size) {
 226                                 pr_warn("Too large reserve pool specified, max "
 227                                         "is %llu KB\n", c->mtd->size / 1024);
 228                                 return -EINVAL;
 229                         }
 230                         c->mount_opts.rp_size = opt;
 231                         break;
 232                 default:
 233                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
 234                                p);
 235                         return -EINVAL;
 236                 }
 237         }
 238
 239         return 0;
 240 }
 241
 242 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 243 {
 244         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 245         int err;
 246
 247         sync_filesystem(sb);
 248         err = jffs2_parse_options(c, data);
 249         if (err)
 250                 return -EINVAL;
 251
 252         return jffs2_do_remount_fs(sb, flags, data);
 253 }
 254
 255 static const struct super_operations jffs2_super_operations =
 256 {
 257         .alloc_inode =  jffs2_alloc_inode,
 258         .destroy_inode =jffs2_destroy_inode,
 259         .put_super =    jffs2_put_super,
 260         .statfs =       jffs2_statfs,
 261         .remount_fs =   jffs2_remount_fs,
 262         .evict_inode =  jffs2_evict_inode,
 263         .dirty_inode =  jffs2_dirty_inode,
 264         .show_options = jffs2_show_options,
 265         .sync_fs =      jffs2_sync_fs,
 266 };
 267
 268 /*
 269  * fill in the superblock
 270  */
 271 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 272 {
 273         struct jffs2_sb_info *c;
 274         int ret;
 275
 276         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 277                   " New superblock for device %d (\"%s\")\n",
 278                   sb->s_mtd->index, sb->s_mtd->name);
 279
 280         c = kzalloc(sizeof(*c), GFP_KERNEL);
 281         if (!c)
 282                 return -ENOMEM;
 283
 284         c->mtd = sb->s_mtd;
 285         c->os_priv = sb;
 286         sb->s_fs_info = c;
 287
 288         ret = jffs2_parse_options(c, data);
 289         if (ret)
 290                 return -EINVAL;
 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 | SB_NOATIME;
 304         sb->s_xattr = jffs2_xattr_handlers;
 305 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 306         sb->s_flags |= SB_POSIXACL;
 307 #endif
 308         ret = jffs2_do_fill_super(sb, data, silent);
 309         return ret;
 310 }
 311
 312 static 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
 319 static 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         kvfree(c->blocks);
 334         jffs2_flash_cleanup(c);
 335         kfree(c->inocache_list);
 336         jffs2_clear_xattr_subsystem(c);
 337         mtd_sync(c->mtd);
 338         jffs2_dbg(1, "%s(): returning\n", __func__);
 339 }
 340
 341 static void jffs2_kill_sb(struct super_block *sb)
 342 {
 343         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 344         if (c && !sb_rdonly(sb))
 345                 jffs2_stop_garbage_collect_thread(c);
 346         kill_mtd_super(sb);
 347         kfree(c);
 348 }
 349
 350 static struct file_system_type jffs2_fs_type = {
 351         .owner =        THIS_MODULE,
 352         .name =         "jffs2",
 353         .mount =        jffs2_mount,
 354         .kill_sb =      jffs2_kill_sb,
 355 };
 356 MODULE_ALIAS_FS("jffs2");
 357
 358 static int __init init_jffs2_fs(void)
 359 {
 360         int ret;
 361
 362         /* Paranoia checks for on-medium structures. If we ask GCC
 363            to pack them with __attribute__((packed)) then it _also_
 364            assumes that they're not aligned -- so it emits crappy
 365            code on some architectures. Ideally we want an attribute
 366            which means just 'no padding', without the alignment
 367            thing. But GCC doesn't have that -- we have to just
 368            hope the structs are the right sizes, instead. */
 369         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 370         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 371         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 372         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 373
 374         pr_info("version 2.2."
 375 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 376                " (NAND)"
 377 #endif
 378 #ifdef CONFIG_JFFS2_SUMMARY
 379                " (SUMMARY) "
 380 #endif
 381                " © 2001-2006 Red Hat, Inc.\n");
 382
 383         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 384                                              sizeof(struct jffs2_inode_info),
 385                                              0, (SLAB_RECLAIM_ACCOUNT|
 386                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 387                                              jffs2_i_init_once);
 388         if (!jffs2_inode_cachep) {
 389                 pr_err("error: Failed to initialise inode cache\n");
 390                 return -ENOMEM;
 391         }
 392         ret = jffs2_compressors_init();
 393         if (ret) {
 394                 pr_err("error: Failed to initialise compressors\n");
 395                 goto out;
 396         }
 397         ret = jffs2_create_slab_caches();
 398         if (ret) {
 399                 pr_err("error: Failed to initialise slab caches\n");
 400                 goto out_compressors;
 401         }
 402         ret = register_filesystem(&jffs2_fs_type);
 403         if (ret) {
 404                 pr_err("error: Failed to register filesystem\n");
 405                 goto out_slab;
 406         }
 407         return 0;
 408
 409  out_slab:
 410         jffs2_destroy_slab_caches();
 411  out_compressors:
 412         jffs2_compressors_exit();
 413  out:
 414         kmem_cache_destroy(jffs2_inode_cachep);
 415         return ret;
 416 }
 417
 418 static void __exit exit_jffs2_fs(void)
 419 {
 420         unregister_filesystem(&jffs2_fs_type);
 421         jffs2_destroy_slab_caches();
 422         jffs2_compressors_exit();
 423
 424         /*
 425          * Make sure all delayed rcu free inodes are flushed before we
 426          * destroy cache.
 427          */
 428         rcu_barrier();
 429         kmem_cache_destroy(jffs2_inode_cachep);
 430 }
 431
 432 module_init(init_jffs2_fs);
 433 module_exit(exit_jffs2_fs);
 434
 435 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 436 MODULE_AUTHOR("Red Hat, Inc.");
 437 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 438                        // the sake of this tag. It's Free Software.