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         lock_super(sb);
  71         sb->s_dirt = 0;
  72
  73         if (!(sb->s_flags & MS_RDONLY)) {
  74                 jffs2_dbg(1, "%s()\n", __func__);
  75                 jffs2_flush_wbuf_gc(c, 0);
  76         }
  77
  78         unlock_super(sb);
  79 }
  80
  81 static const char *jffs2_compr_name(unsigned int compr)
  82 {
  83         switch (compr) {
  84         case JFFS2_COMPR_MODE_NONE:
  85                 return "none";
  86 #ifdef CONFIG_JFFS2_LZO
  87         case JFFS2_COMPR_MODE_FORCELZO:
  88                 return "lzo";
  89 #endif
  90 #ifdef CONFIG_JFFS2_ZLIB
  91         case JFFS2_COMPR_MODE_FORCEZLIB:
  92                 return "zlib";
  93 #endif
  94         default:
  95                 /* should never happen; programmer error */
  96                 WARN_ON(1);
  97                 return "";
  98         }
  99 }
 100
 101 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
 102 {
 103         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
 104         struct jffs2_mount_opts *opts = &c->mount_opts;
 105
 106         if (opts->override_compr)
 107                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
 108         if (opts->rp_size)
 109                 seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
 110
 111         return 0;
 112 }
 113
 114 static int jffs2_sync_fs(struct super_block *sb, int wait)
 115 {
 116         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 117
 118         jffs2_write_super(sb);
 119
 120         mutex_lock(&c->alloc_sem);
 121         jffs2_flush_wbuf_pad(c);
 122         mutex_unlock(&c->alloc_sem);
 123         return 0;
 124 }
 125
 126 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 127                                          uint32_t generation)
 128 {
 129         /* We don't care about i_generation. We'll destroy the flash
 130            before we start re-using inode numbers anyway. And even
 131            if that wasn't true, we'd have other problems...*/
 132         return jffs2_iget(sb, ino);
 133 }
 134
 135 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 136                                          int fh_len, int fh_type)
 137 {
 138         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 139                                     jffs2_nfs_get_inode);
 140 }
 141
 142 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 143                                          int fh_len, int fh_type)
 144 {
 145         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 146                                     jffs2_nfs_get_inode);
 147 }
 148
 149 static struct dentry *jffs2_get_parent(struct dentry *child)
 150 {
 151         struct jffs2_inode_info *f;
 152         uint32_t pino;
 153
 154         BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 155
 156         f = JFFS2_INODE_INFO(child->d_inode);
 157
 158         pino = f->inocache->pino_nlink;
 159
 160         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 161                     f->inocache->ino, pino);
 162
 163         return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 164 }
 165
 166 static const struct export_operations jffs2_export_ops = {
 167         .get_parent = jffs2_get_parent,
 168         .fh_to_dentry = jffs2_fh_to_dentry,
 169         .fh_to_parent = jffs2_fh_to_parent,
 170 };
 171
 172 /*
 173  * JFFS2 mount options.
 174  *
 175  * Opt_override_compr: override default compressor
 176  * Opt_rp_size: size of reserved pool in KiB
 177  * Opt_err: just end of array marker
 178  */
 179 enum {
 180         Opt_override_compr,
 181         Opt_rp_size,
 182         Opt_err,
 183 };
 184
 185 static const match_table_t tokens = {
 186         {Opt_override_compr, "compr=%s"},
 187         {Opt_rp_size, "rp_size=%u"},
 188         {Opt_err, NULL},
 189 };
 190
 191 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 192 {
 193         substring_t args[MAX_OPT_ARGS];
 194         char *p, *name;
 195         unsigned int opt;
 196
 197         if (!data)
 198                 return 0;
 199
 200         while ((p = strsep(&data, ","))) {
 201                 int token;
 202
 203                 if (!*p)
 204                         continue;
 205
 206                 token = match_token(p, tokens, args);
 207                 switch (token) {
 208                 case Opt_override_compr:
 209                         name = match_strdup(&args[0]);
 210
 211                         if (!name)
 212                                 return -ENOMEM;
 213                         if (!strcmp(name, "none"))
 214                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 215 #ifdef CONFIG_JFFS2_LZO
 216                         else if (!strcmp(name, "lzo"))
 217                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 218 #endif
 219 #ifdef CONFIG_JFFS2_ZLIB
 220                         else if (!strcmp(name, "zlib"))
 221                                 c->mount_opts.compr =
 222                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 223 #endif
 224                         else {
 225                                 pr_err("Error: unknown compressor \"%s\"\n",
 226                                        name);
 227                                 kfree(name);
 228                                 return -EINVAL;
 229                         }
 230                         kfree(name);
 231                         c->mount_opts.override_compr = true;
 232                         break;
 233                 case Opt_rp_size:
 234                         if (match_int(&args[0], &opt))
 235                                 return -EINVAL;
 236                         opt *= 1024;
 237                         if (opt > c->mtd->size) {
 238                                 pr_warn("Too large reserve pool specified, max "
 239                                         "is %llu KB\n", c->mtd->size / 1024);
 240                                 return -EINVAL;
 241                         }
 242                         c->mount_opts.rp_size = opt;
 243                         break;
 244                 default:
 245                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
 246                                p);
 247                         return -EINVAL;
 248                 }
 249         }
 250
 251         return 0;
 252 }
 253
 254 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 255 {
 256         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 257         int err;
 258
 259         err = jffs2_parse_options(c, data);
 260         if (err)
 261                 return -EINVAL;
 262
 263         return jffs2_do_remount_fs(sb, flags, data);
 264 }
 265
 266 static const struct super_operations jffs2_super_operations =
 267 {
 268         .alloc_inode =  jffs2_alloc_inode,
 269         .destroy_inode =jffs2_destroy_inode,
 270         .put_super =    jffs2_put_super,
 271         .write_super =  jffs2_write_super,
 272         .statfs =       jffs2_statfs,
 273         .remount_fs =   jffs2_remount_fs,
 274         .evict_inode =  jffs2_evict_inode,
 275         .dirty_inode =  jffs2_dirty_inode,
 276         .show_options = jffs2_show_options,
 277         .sync_fs =      jffs2_sync_fs,
 278 };
 279
 280 /*
 281  * fill in the superblock
 282  */
 283 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 284 {
 285         struct jffs2_sb_info *c;
 286         int ret;
 287
 288         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 289                   " New superblock for device %d (\"%s\")\n",
 290                   sb->s_mtd->index, sb->s_mtd->name);
 291
 292         c = kzalloc(sizeof(*c), GFP_KERNEL);
 293         if (!c)
 294                 return -ENOMEM;
 295
 296         c->mtd = sb->s_mtd;
 297         c->os_priv = sb;
 298         sb->s_fs_info = c;
 299
 300         ret = jffs2_parse_options(c, data);
 301         if (ret) {
 302                 kfree(c);
 303                 return -EINVAL;
 304         }
 305
 306         /* Initialize JFFS2 superblock locks, the further initialization will
 307          * be done later */
 308         mutex_init(&c->alloc_sem);
 309         mutex_init(&c->erase_free_sem);
 310         init_waitqueue_head(&c->erase_wait);
 311         init_waitqueue_head(&c->inocache_wq);
 312         spin_lock_init(&c->erase_completion_lock);
 313         spin_lock_init(&c->inocache_lock);
 314
 315         sb->s_op = &jffs2_super_operations;
 316         sb->s_export_op = &jffs2_export_ops;
 317         sb->s_flags = sb->s_flags | MS_NOATIME;
 318         sb->s_xattr = jffs2_xattr_handlers;
 319 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 320         sb->s_flags |= MS_POSIXACL;
 321 #endif
 322         ret = jffs2_do_fill_super(sb, data, silent);
 323         return ret;
 324 }
 325
 326 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
 327                         int flags, const char *dev_name,
 328                         void *data)
 329 {
 330         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
 331 }
 332
 333 static void jffs2_put_super (struct super_block *sb)
 334 {
 335         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 336
 337         jffs2_dbg(2, "%s()\n", __func__);
 338
 339         if (sb->s_dirt)
 340                 jffs2_write_super(sb);
 341
 342         mutex_lock(&c->alloc_sem);
 343         jffs2_flush_wbuf_pad(c);
 344         mutex_unlock(&c->alloc_sem);
 345
 346         jffs2_sum_exit(c);
 347
 348         jffs2_free_ino_caches(c);
 349         jffs2_free_raw_node_refs(c);
 350         if (jffs2_blocks_use_vmalloc(c))
 351                 vfree(c->blocks);
 352         else
 353                 kfree(c->blocks);
 354         jffs2_flash_cleanup(c);
 355         kfree(c->inocache_list);
 356         jffs2_clear_xattr_subsystem(c);
 357         mtd_sync(c->mtd);
 358         jffs2_dbg(1, "%s(): returning\n", __func__);
 359 }
 360
 361 static void jffs2_kill_sb(struct super_block *sb)
 362 {
 363         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 364         if (!(sb->s_flags & MS_RDONLY))
 365                 jffs2_stop_garbage_collect_thread(c);
 366         kill_mtd_super(sb);
 367         kfree(c);
 368 }
 369
 370 static struct file_system_type jffs2_fs_type = {
 371         .owner =        THIS_MODULE,
 372         .name =         "jffs2",
 373         .mount =        jffs2_mount,
 374         .kill_sb =      jffs2_kill_sb,
 375 };
 376
 377 static int __init init_jffs2_fs(void)
 378 {
 379         int ret;
 380
 381         /* Paranoia checks for on-medium structures. If we ask GCC
 382            to pack them with __attribute__((packed)) then it _also_
 383            assumes that they're not aligned -- so it emits crappy
 384            code on some architectures. Ideally we want an attribute
 385            which means just 'no padding', without the alignment
 386            thing. But GCC doesn't have that -- we have to just
 387            hope the structs are the right sizes, instead. */
 388         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 389         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 390         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 391         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 392
 393         pr_info("version 2.2."
 394 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 395                " (NAND)"
 396 #endif
 397 #ifdef CONFIG_JFFS2_SUMMARY
 398                " (SUMMARY) "
 399 #endif
 400                " © 2001-2006 Red Hat, Inc.\n");
 401
 402         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 403                                              sizeof(struct jffs2_inode_info),
 404                                              0, (SLAB_RECLAIM_ACCOUNT|
 405                                                 SLAB_MEM_SPREAD),
 406                                              jffs2_i_init_once);
 407         if (!jffs2_inode_cachep) {
 408                 pr_err("error: Failed to initialise inode cache\n");
 409                 return -ENOMEM;
 410         }
 411         ret = jffs2_compressors_init();
 412         if (ret) {
 413                 pr_err("error: Failed to initialise compressors\n");
 414                 goto out;
 415         }
 416         ret = jffs2_create_slab_caches();
 417         if (ret) {
 418                 pr_err("error: Failed to initialise slab caches\n");
 419                 goto out_compressors;
 420         }
 421         ret = register_filesystem(&jffs2_fs_type);
 422         if (ret) {
 423                 pr_err("error: Failed to register filesystem\n");
 424                 goto out_slab;
 425         }
 426         return 0;
 427
 428  out_slab:
 429         jffs2_destroy_slab_caches();
 430  out_compressors:
 431         jffs2_compressors_exit();
 432  out:
 433         kmem_cache_destroy(jffs2_inode_cachep);
 434         return ret;
 435 }
 436
 437 static void __exit exit_jffs2_fs(void)
 438 {
 439         unregister_filesystem(&jffs2_fs_type);
 440         jffs2_destroy_slab_caches();
 441         jffs2_compressors_exit();
 442         kmem_cache_destroy(jffs2_inode_cachep);
 443 }
 444
 445 module_init(init_jffs2_fs);
 446 module_exit(exit_jffs2_fs);
 447
 448 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 449 MODULE_AUTHOR("Red Hat, Inc.");
 450 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 451                        // the sake of this tag. It's Free Software.