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         mutex_lock(&c->alloc_sem);
 104         jffs2_flush_wbuf_pad(c);
 105         mutex_unlock(&c->alloc_sem);
 106         return 0;
 107 }
 108
 109 static 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
 118 static 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
 125 static 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
 132 static 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
 149 static 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  */
 162 enum {
 163         Opt_override_compr,
 164         Opt_rp_size,
 165         Opt_err,
 166 };
 167
 168 static const match_table_t tokens = {
 169         {Opt_override_compr, "compr=%s"},
 170         {Opt_rp_size, "rp_size=%u"},
 171         {Opt_err, NULL},
 172 };
 173
 174 static 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
 237 static 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
 249 static 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  */
 265 static 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
 308 static 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
 315 static 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
 340 static 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
 349 static 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
 356 static 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
 416 static void __exit exit_jffs2_fs(void)
 417 {
 418         unregister_filesystem(&jffs2_fs_type);
 419         jffs2_destroy_slab_caches();
 420         jffs2_compressors_exit();
 421
 422         /*
 423          * Make sure all delayed rcu free inodes are flushed before we
 424          * destroy cache.
 425          */
 426         rcu_barrier();
 427         kmem_cache_destroy(jffs2_inode_cachep);
 428 }
 429
 430 module_init(init_jffs2_fs);
 431 module_exit(exit_jffs2_fs);
 432
 433 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 434 MODULE_AUTHOR("Red Hat, Inc.");
 435 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 436                        // the sake of this tag. It's Free Software.