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 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/init.h>
  16 #include <linux/list.h>
  17 #include <linux/fs.h>
  18 #include <linux/err.h>
  19 #include <linux/mount.h>
  20 #include <linux/parser.h>
  21 #include <linux/jffs2.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/mtd/super.h>
  24 #include <linux/ctype.h>
  25 #include <linux/namei.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/exportfs.h>
  28 #include "compr.h"
  29 #include "nodelist.h"
  30
  31 static void jffs2_put_super(struct super_block *);
  32
  33 static struct kmem_cache *jffs2_inode_cachep;
  34
  35 static struct inode *jffs2_alloc_inode(struct super_block *sb)
  36 {
  37         struct jffs2_inode_info *f;
  38
  39         f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
  40         if (!f)
  41                 return NULL;
  42         return &f->vfs_inode;
  43 }
  44
  45 static void jffs2_i_callback(struct rcu_head *head)
  46 {
  47         struct inode *inode = container_of(head, struct inode, i_rcu);
  48         kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  49 }
  50
  51 static void jffs2_destroy_inode(struct inode *inode)
  52 {
  53         call_rcu(&inode->i_rcu, jffs2_i_callback);
  54 }
  55
  56 static void jffs2_i_init_once(void *foo)
  57 {
  58         struct jffs2_inode_info *f = foo;
  59
  60         mutex_init(&f->sem);
  61         inode_init_once(&f->vfs_inode);
  62 }
  63
  64 static void jffs2_write_super(struct super_block *sb)
  65 {
  66         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  67
  68         lock_super(sb);
  69         sb->s_dirt = 0;
  70
  71         if (!(sb->s_flags & MS_RDONLY)) {
  72                 D1(printk(KERN_DEBUG "jffs2_write_super()\n"));
  73                 jffs2_flush_wbuf_gc(c, 0);
  74         }
  75
  76         unlock_super(sb);
  77 }
  78
  79 static const char *jffs2_compr_name(unsigned int compr)
  80 {
  81         switch (compr) {
  82         case JFFS2_COMPR_MODE_NONE:
  83                 return "none";
  84 #ifdef CONFIG_JFFS2_LZO
  85         case JFFS2_COMPR_MODE_FORCELZO:
  86                 return "lzo";
  87 #endif
  88 #ifdef CONFIG_JFFS2_ZLIB
  89         case JFFS2_COMPR_MODE_FORCEZLIB:
  90                 return "zlib";
  91 #endif
  92         default:
  93                 /* should never happen; programmer error */
  94                 WARN_ON(1);
  95                 return "";
  96         }
  97 }
  98
  99 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
 100 {
 101         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
 102         struct jffs2_mount_opts *opts = &c->mount_opts;
 103
 104         if (opts->override_compr)
 105                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
 106
 107         return 0;
 108 }
 109
 110 static int jffs2_sync_fs(struct super_block *sb, int wait)
 111 {
 112         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 113
 114         jffs2_write_super(sb);
 115
 116         mutex_lock(&c->alloc_sem);
 117         jffs2_flush_wbuf_pad(c);
 118         mutex_unlock(&c->alloc_sem);
 119         return 0;
 120 }
 121
 122 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 123                                          uint32_t generation)
 124 {
 125         /* We don't care about i_generation. We'll destroy the flash
 126            before we start re-using inode numbers anyway. And even
 127            if that wasn't true, we'd have other problems...*/
 128         return jffs2_iget(sb, ino);
 129 }
 130
 131 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 132                                          int fh_len, int fh_type)
 133 {
 134         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 135                                     jffs2_nfs_get_inode);
 136 }
 137
 138 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 139                                          int fh_len, int fh_type)
 140 {
 141         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 142                                     jffs2_nfs_get_inode);
 143 }
 144
 145 static struct dentry *jffs2_get_parent(struct dentry *child)
 146 {
 147         struct jffs2_inode_info *f;
 148         uint32_t pino;
 149
 150         BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 151
 152         f = JFFS2_INODE_INFO(child->d_inode);
 153
 154         pino = f->inocache->pino_nlink;
 155
 156         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 157                     f->inocache->ino, pino);
 158
 159         return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 160 }
 161
 162 static const struct export_operations jffs2_export_ops = {
 163         .get_parent = jffs2_get_parent,
 164         .fh_to_dentry = jffs2_fh_to_dentry,
 165         .fh_to_parent = jffs2_fh_to_parent,
 166 };
 167
 168 /*
 169  * JFFS2 mount options.
 170  *
 171  * Opt_override_compr: override default compressor
 172  * Opt_err: just end of array marker
 173  */
 174 enum {
 175         Opt_override_compr,
 176         Opt_err,
 177 };
 178
 179 static const match_table_t tokens = {
 180         {Opt_override_compr, "compr=%s"},
 181         {Opt_err, NULL},
 182 };
 183
 184 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 185 {
 186         substring_t args[MAX_OPT_ARGS];
 187         char *p, *name;
 188
 189         if (!data)
 190                 return 0;
 191
 192         while ((p = strsep(&data, ","))) {
 193                 int token;
 194
 195                 if (!*p)
 196                         continue;
 197
 198                 token = match_token(p, tokens, args);
 199                 switch (token) {
 200                 case Opt_override_compr:
 201                         name = match_strdup(&args[0]);
 202
 203                         if (!name)
 204                                 return -ENOMEM;
 205                         if (!strcmp(name, "none"))
 206                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 207 #ifdef CONFIG_JFFS2_LZO
 208                         else if (!strcmp(name, "lzo"))
 209                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 210 #endif
 211 #ifdef CONFIG_JFFS2_ZLIB
 212                         else if (!strcmp(name, "zlib"))
 213                                 c->mount_opts.compr =
 214                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 215 #endif
 216                         else {
 217                                 printk(KERN_ERR "JFFS2 Error: unknown compressor \"%s\"",
 218                                                 name);
 219                                 kfree(name);
 220                                 return -EINVAL;
 221                         }
 222                         kfree(name);
 223                         c->mount_opts.override_compr = true;
 224                         break;
 225                 default:
 226                         printk(KERN_ERR "JFFS2 Error: unrecognized mount option '%s' or missing value\n",
 227                                         p);
 228                         return -EINVAL;
 229                 }
 230         }
 231
 232         return 0;
 233 }
 234
 235 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 236 {
 237         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 238         int err;
 239
 240         err = jffs2_parse_options(c, data);
 241         if (err)
 242                 return -EINVAL;
 243
 244         return jffs2_do_remount_fs(sb, flags, data);
 245 }
 246
 247 static const struct super_operations jffs2_super_operations =
 248 {
 249         .alloc_inode =  jffs2_alloc_inode,
 250         .destroy_inode =jffs2_destroy_inode,
 251         .put_super =    jffs2_put_super,
 252         .write_super =  jffs2_write_super,
 253         .statfs =       jffs2_statfs,
 254         .remount_fs =   jffs2_remount_fs,
 255         .evict_inode =  jffs2_evict_inode,
 256         .dirty_inode =  jffs2_dirty_inode,
 257         .show_options = jffs2_show_options,
 258         .sync_fs =      jffs2_sync_fs,
 259 };
 260
 261 /*
 262  * fill in the superblock
 263  */
 264 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 265 {
 266         struct jffs2_sb_info *c;
 267         int ret;
 268
 269         D1(printk(KERN_DEBUG "jffs2_get_sb_mtd():"
 270                   " New superblock for device %d (\"%s\")\n",
 271                   sb->s_mtd->index, sb->s_mtd->name));
 272
 273         c = kzalloc(sizeof(*c), GFP_KERNEL);
 274         if (!c)
 275                 return -ENOMEM;
 276
 277         c->mtd = sb->s_mtd;
 278         c->os_priv = sb;
 279         sb->s_fs_info = c;
 280
 281         ret = jffs2_parse_options(c, data);
 282         if (ret) {
 283                 kfree(c);
 284                 return -EINVAL;
 285         }
 286
 287         /* Initialize JFFS2 superblock locks, the further initialization will
 288          * be done later */
 289         mutex_init(&c->alloc_sem);
 290         mutex_init(&c->erase_free_sem);
 291         init_waitqueue_head(&c->erase_wait);
 292         init_waitqueue_head(&c->inocache_wq);
 293         spin_lock_init(&c->erase_completion_lock);
 294         spin_lock_init(&c->inocache_lock);
 295
 296         sb->s_op = &jffs2_super_operations;
 297         sb->s_export_op = &jffs2_export_ops;
 298         sb->s_flags = sb->s_flags | MS_NOATIME;
 299         sb->s_xattr = jffs2_xattr_handlers;
 300 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 301         sb->s_flags |= MS_POSIXACL;
 302 #endif
 303         ret = jffs2_do_fill_super(sb, data, silent);
 304         return ret;
 305 }
 306
 307 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
 308                         int flags, const char *dev_name,
 309                         void *data)
 310 {
 311         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
 312 }
 313
 314 static void jffs2_put_super (struct super_block *sb)
 315 {
 316         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 317
 318         D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 319
 320         if (sb->s_dirt)
 321                 jffs2_write_super(sb);
 322
 323         mutex_lock(&c->alloc_sem);
 324         jffs2_flush_wbuf_pad(c);
 325         mutex_unlock(&c->alloc_sem);
 326
 327         jffs2_sum_exit(c);
 328
 329         jffs2_free_ino_caches(c);
 330         jffs2_free_raw_node_refs(c);
 331         if (jffs2_blocks_use_vmalloc(c))
 332                 vfree(c->blocks);
 333         else
 334                 kfree(c->blocks);
 335         jffs2_flash_cleanup(c);
 336         kfree(c->inocache_list);
 337         jffs2_clear_xattr_subsystem(c);
 338         if (c->mtd->sync)
 339                 c->mtd->sync(c->mtd);
 340
 341         D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 342 }
 343
 344 static 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
 353 static 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
 360 static 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         printk(KERN_INFO "JFFS2 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                 printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 392                 return -ENOMEM;
 393         }
 394         ret = jffs2_compressors_init();
 395         if (ret) {
 396                 printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
 397                 goto out;
 398         }
 399         ret = jffs2_create_slab_caches();
 400         if (ret) {
 401                 printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 402                 goto out_compressors;
 403         }
 404         ret = register_filesystem(&jffs2_fs_type);
 405         if (ret) {
 406                 printk(KERN_ERR "JFFS2 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
 420 static void __exit exit_jffs2_fs(void)
 421 {
 422         unregister_filesystem(&jffs2_fs_type);
 423         jffs2_destroy_slab_caches();
 424         jffs2_compressors_exit();
 425         kmem_cache_destroy(jffs2_inode_cachep);
 426 }
 427
 428 module_init(init_jffs2_fs);
 429 module_exit(exit_jffs2_fs);
 430
 431 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 432 MODULE_AUTHOR("Red Hat, Inc.");
 433 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 434                        // the sake of this tag. It's Free Software.