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         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  51
  52         kfree(f->target);
  53         kmem_cache_free(jffs2_inode_cachep, f);
  54 }
  55
  56 static void jffs2_destroy_inode(struct inode *inode)
  57 {
  58         call_rcu(&inode->i_rcu, jffs2_i_callback);
  59 }
  60
  61 static void jffs2_i_init_once(void *foo)
  62 {
  63         struct jffs2_inode_info *f = foo;
  64
  65         mutex_init(&f->sem);
  66         inode_init_once(&f->vfs_inode);
  67 }
  68
  69 static const char *jffs2_compr_name(unsigned int compr)
  70 {
  71         switch (compr) {
  72         case JFFS2_COMPR_MODE_NONE:
  73                 return "none";
  74 #ifdef CONFIG_JFFS2_LZO
  75         case JFFS2_COMPR_MODE_FORCELZO:
  76                 return "lzo";
  77 #endif
  78 #ifdef CONFIG_JFFS2_ZLIB
  79         case JFFS2_COMPR_MODE_FORCEZLIB:
  80                 return "zlib";
  81 #endif
  82         default:
  83                 /* should never happen; programmer error */
  84                 WARN_ON(1);
  85                 return "";
  86         }
  87 }
  88
  89 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
  90 {
  91         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
  92         struct jffs2_mount_opts *opts = &c->mount_opts;
  93
  94         if (opts->override_compr)
  95                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
  96         if (opts->rp_size)
  97                 seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
  98
  99         return 0;
 100 }
 101
 102 static int jffs2_sync_fs(struct super_block *sb, int wait)
 103 {
 104         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 105
 106 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 107         if (jffs2_is_writebuffered(c))
 108                 cancel_delayed_work_sync(&c->wbuf_dwork);
 109 #endif
 110
 111         mutex_lock(&c->alloc_sem);
 112         jffs2_flush_wbuf_pad(c);
 113         mutex_unlock(&c->alloc_sem);
 114         return 0;
 115 }
 116
 117 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 118                                          uint32_t generation)
 119 {
 120         /* We don't care about i_generation. We'll destroy the flash
 121            before we start re-using inode numbers anyway. And even
 122            if that wasn't true, we'd have other problems...*/
 123         return jffs2_iget(sb, ino);
 124 }
 125
 126 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 127                                          int fh_len, int fh_type)
 128 {
 129         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 130                                     jffs2_nfs_get_inode);
 131 }
 132
 133 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 134                                          int fh_len, int fh_type)
 135 {
 136         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 137                                     jffs2_nfs_get_inode);
 138 }
 139
 140 static struct dentry *jffs2_get_parent(struct dentry *child)
 141 {
 142         struct jffs2_inode_info *f;
 143         uint32_t pino;
 144
 145         BUG_ON(!d_is_dir(child));
 146
 147         f = JFFS2_INODE_INFO(d_inode(child));
 148
 149         pino = f->inocache->pino_nlink;
 150
 151         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 152                     f->inocache->ino, pino);
 153
 154         return d_obtain_alias(jffs2_iget(child->d_sb, pino));
 155 }
 156
 157 static const struct export_operations jffs2_export_ops = {
 158         .get_parent = jffs2_get_parent,
 159         .fh_to_dentry = jffs2_fh_to_dentry,
 160         .fh_to_parent = jffs2_fh_to_parent,
 161 };
 162
 163 /*
 164  * JFFS2 mount options.
 165  *
 166  * Opt_override_compr: override default compressor
 167  * Opt_rp_size: size of reserved pool in KiB
 168  * Opt_err: just end of array marker
 169  */
 170 enum {
 171         Opt_override_compr,
 172         Opt_rp_size,
 173         Opt_err,
 174 };
 175
 176 static const match_table_t tokens = {
 177         {Opt_override_compr, "compr=%s"},
 178         {Opt_rp_size, "rp_size=%u"},
 179         {Opt_err, NULL},
 180 };
 181
 182 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 183 {
 184         substring_t args[MAX_OPT_ARGS];
 185         char *p, *name;
 186         unsigned int opt;
 187
 188         if (!data)
 189                 return 0;
 190
 191         while ((p = strsep(&data, ","))) {
 192                 int token;
 193
 194                 if (!*p)
 195                         continue;
 196
 197                 token = match_token(p, tokens, args);
 198                 switch (token) {
 199                 case Opt_override_compr:
 200                         name = match_strdup(&args[0]);
 201
 202                         if (!name)
 203                                 return -ENOMEM;
 204                         if (!strcmp(name, "none"))
 205                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 206 #ifdef CONFIG_JFFS2_LZO
 207                         else if (!strcmp(name, "lzo"))
 208                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 209 #endif
 210 #ifdef CONFIG_JFFS2_ZLIB
 211                         else if (!strcmp(name, "zlib"))
 212                                 c->mount_opts.compr =
 213                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 214 #endif
 215                         else {
 216                                 pr_err("Error: unknown compressor \"%s\"\n",
 217                                        name);
 218                                 kfree(name);
 219                                 return -EINVAL;
 220                         }
 221                         kfree(name);
 222                         c->mount_opts.override_compr = true;
 223                         break;
 224                 case Opt_rp_size:
 225                         if (match_int(&args[0], &opt))
 226                                 return -EINVAL;
 227                         opt *= 1024;
 228                         if (opt > c->mtd->size) {
 229                                 pr_warn("Too large reserve pool specified, max "
 230                                         "is %llu KB\n", c->mtd->size / 1024);
 231                                 return -EINVAL;
 232                         }
 233                         c->mount_opts.rp_size = opt;
 234                         break;
 235                 default:
 236                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
 237                                p);
 238                         return -EINVAL;
 239                 }
 240         }
 241
 242         return 0;
 243 }
 244
 245 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 246 {
 247         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 248         int err;
 249
 250         sync_filesystem(sb);
 251         err = jffs2_parse_options(c, data);
 252         if (err)
 253                 return -EINVAL;
 254
 255         return jffs2_do_remount_fs(sb, flags, data);
 256 }
 257
 258 static const struct super_operations jffs2_super_operations =
 259 {
 260         .alloc_inode =  jffs2_alloc_inode,
 261         .destroy_inode =jffs2_destroy_inode,
 262         .put_super =    jffs2_put_super,
 263         .statfs =       jffs2_statfs,
 264         .remount_fs =   jffs2_remount_fs,
 265         .evict_inode =  jffs2_evict_inode,
 266         .dirty_inode =  jffs2_dirty_inode,
 267         .show_options = jffs2_show_options,
 268         .sync_fs =      jffs2_sync_fs,
 269 };
 270
 271 /*
 272  * fill in the superblock
 273  */
 274 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 275 {
 276         struct jffs2_sb_info *c;
 277         int ret;
 278
 279         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 280                   " New superblock for device %d (\"%s\")\n",
 281                   sb->s_mtd->index, sb->s_mtd->name);
 282
 283         c = kzalloc(sizeof(*c), GFP_KERNEL);
 284         if (!c)
 285                 return -ENOMEM;
 286
 287         c->mtd = sb->s_mtd;
 288         c->os_priv = sb;
 289         sb->s_fs_info = c;
 290
 291         ret = jffs2_parse_options(c, data);
 292         if (ret)
 293                 return -EINVAL;
 294
 295         /* Initialize JFFS2 superblock locks, the further initialization will
 296          * be done later */
 297         mutex_init(&c->alloc_sem);
 298         mutex_init(&c->erase_free_sem);
 299         init_waitqueue_head(&c->erase_wait);
 300         init_waitqueue_head(&c->inocache_wq);
 301         spin_lock_init(&c->erase_completion_lock);
 302         spin_lock_init(&c->inocache_lock);
 303
 304         sb->s_op = &jffs2_super_operations;
 305         sb->s_export_op = &jffs2_export_ops;
 306         sb->s_flags = sb->s_flags | SB_NOATIME;
 307         sb->s_xattr = jffs2_xattr_handlers;
 308 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 309         sb->s_flags |= SB_POSIXACL;
 310 #endif
 311         ret = jffs2_do_fill_super(sb, data, silent);
 312         return ret;
 313 }
 314
 315 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
 316                         int flags, const char *dev_name,
 317                         void *data)
 318 {
 319         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
 320 }
 321
 322 static void jffs2_put_super (struct super_block *sb)
 323 {
 324         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 325
 326         jffs2_dbg(2, "%s()\n", __func__);
 327
 328         mutex_lock(&c->alloc_sem);
 329         jffs2_flush_wbuf_pad(c);
 330         mutex_unlock(&c->alloc_sem);
 331
 332         jffs2_sum_exit(c);
 333
 334         jffs2_free_ino_caches(c);
 335         jffs2_free_raw_node_refs(c);
 336         kvfree(c->blocks);
 337         jffs2_flash_cleanup(c);
 338         kfree(c->inocache_list);
 339         jffs2_clear_xattr_subsystem(c);
 340         mtd_sync(c->mtd);
 341         jffs2_dbg(1, "%s(): returning\n", __func__);
 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 (c && !sb_rdonly(sb))
 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 MODULE_ALIAS_FS("jffs2");
 360
 361 static int __init init_jffs2_fs(void)
 362 {
 363         int ret;
 364
 365         /* Paranoia checks for on-medium structures. If we ask GCC
 366            to pack them with __attribute__((packed)) then it _also_
 367            assumes that they're not aligned -- so it emits crappy
 368            code on some architectures. Ideally we want an attribute
 369            which means just 'no padding', without the alignment
 370            thing. But GCC doesn't have that -- we have to just
 371            hope the structs are the right sizes, instead. */
 372         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 373         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 374         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 375         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 376
 377         pr_info("version 2.2."
 378 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 379                " (NAND)"
 380 #endif
 381 #ifdef CONFIG_JFFS2_SUMMARY
 382                " (SUMMARY) "
 383 #endif
 384                " © 2001-2006 Red Hat, Inc.\n");
 385
 386         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 387                                              sizeof(struct jffs2_inode_info),
 388                                              0, (SLAB_RECLAIM_ACCOUNT|
 389                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 390                                              jffs2_i_init_once);
 391         if (!jffs2_inode_cachep) {
 392                 pr_err("error: Failed to initialise inode cache\n");
 393                 return -ENOMEM;
 394         }
 395         ret = jffs2_compressors_init();
 396         if (ret) {
 397                 pr_err("error: Failed to initialise compressors\n");
 398                 goto out;
 399         }
 400         ret = jffs2_create_slab_caches();
 401         if (ret) {
 402                 pr_err("error: Failed to initialise slab caches\n");
 403                 goto out_compressors;
 404         }
 405         ret = register_filesystem(&jffs2_fs_type);
 406         if (ret) {
 407                 pr_err("error: Failed to register filesystem\n");
 408                 goto out_slab;
 409         }
 410         return 0;
 411
 412  out_slab:
 413         jffs2_destroy_slab_caches();
 414  out_compressors:
 415         jffs2_compressors_exit();
 416  out:
 417         kmem_cache_destroy(jffs2_inode_cachep);
 418         return ret;
 419 }
 420
 421 static void __exit exit_jffs2_fs(void)
 422 {
 423         unregister_filesystem(&jffs2_fs_type);
 424         jffs2_destroy_slab_caches();
 425         jffs2_compressors_exit();
 426
 427         /*
 428          * Make sure all delayed rcu free inodes are flushed before we
 429          * destroy cache.
 430          */
 431         rcu_barrier();
 432         kmem_cache_destroy(jffs2_inode_cachep);
 433 }
 434
 435 module_init(init_jffs2_fs);
 436 module_exit(exit_jffs2_fs);
 437
 438 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 439 MODULE_AUTHOR("Red Hat, Inc.");
 440 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 441                        // the sake of this tag. It's Free Software.