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_free_inode(struct inode *inode)
  48 {
  49         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  50
  51         kfree(f->target);
  52         kmem_cache_free(jffs2_inode_cachep, f);
  53 }
  54
  55 static void jffs2_i_init_once(void *foo)
  56 {
  57         struct jffs2_inode_info *f = foo;
  58
  59         mutex_init(&f->sem);
  60         inode_init_once(&f->vfs_inode);
  61 }
  62
  63 static const char *jffs2_compr_name(unsigned int compr)
  64 {
  65         switch (compr) {
  66         case JFFS2_COMPR_MODE_NONE:
  67                 return "none";
  68 #ifdef CONFIG_JFFS2_LZO
  69         case JFFS2_COMPR_MODE_FORCELZO:
  70                 return "lzo";
  71 #endif
  72 #ifdef CONFIG_JFFS2_ZLIB
  73         case JFFS2_COMPR_MODE_FORCEZLIB:
  74                 return "zlib";
  75 #endif
  76         default:
  77                 /* should never happen; programmer error */
  78                 WARN_ON(1);
  79                 return "";
  80         }
  81 }
  82
  83 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
  84 {
  85         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
  86         struct jffs2_mount_opts *opts = &c->mount_opts;
  87
  88         if (opts->override_compr)
  89                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
  90         if (opts->rp_size)
  91                 seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
  92
  93         return 0;
  94 }
  95
  96 static int jffs2_sync_fs(struct super_block *sb, int wait)
  97 {
  98         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  99
 100 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 101         if (jffs2_is_writebuffered(c))
 102                 cancel_delayed_work_sync(&c->wbuf_dwork);
 103 #endif
 104
 105         mutex_lock(&c->alloc_sem);
 106         jffs2_flush_wbuf_pad(c);
 107         mutex_unlock(&c->alloc_sem);
 108         return 0;
 109 }
 110
 111 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 112                                          uint32_t generation)
 113 {
 114         /* We don't care about i_generation. We'll destroy the flash
 115            before we start re-using inode numbers anyway. And even
 116            if that wasn't true, we'd have other problems...*/
 117         return jffs2_iget(sb, ino);
 118 }
 119
 120 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 121                                          int fh_len, int fh_type)
 122 {
 123         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 124                                     jffs2_nfs_get_inode);
 125 }
 126
 127 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 128                                          int fh_len, int fh_type)
 129 {
 130         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 131                                     jffs2_nfs_get_inode);
 132 }
 133
 134 static struct dentry *jffs2_get_parent(struct dentry *child)
 135 {
 136         struct jffs2_inode_info *f;
 137         uint32_t pino;
 138
 139         BUG_ON(!d_is_dir(child));
 140
 141         f = JFFS2_INODE_INFO(d_inode(child));
 142
 143         pino = f->inocache->pino_nlink;
 144
 145         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 146                     f->inocache->ino, pino);
 147
 148         return d_obtain_alias(jffs2_iget(child->d_sb, pino));
 149 }
 150
 151 static const struct export_operations jffs2_export_ops = {
 152         .get_parent = jffs2_get_parent,
 153         .fh_to_dentry = jffs2_fh_to_dentry,
 154         .fh_to_parent = jffs2_fh_to_parent,
 155 };
 156
 157 /*
 158  * JFFS2 mount options.
 159  *
 160  * Opt_override_compr: override default compressor
 161  * Opt_rp_size: size of reserved pool in KiB
 162  * Opt_err: just end of array marker
 163  */
 164 enum {
 165         Opt_override_compr,
 166         Opt_rp_size,
 167         Opt_err,
 168 };
 169
 170 static const match_table_t tokens = {
 171         {Opt_override_compr, "compr=%s"},
 172         {Opt_rp_size, "rp_size=%u"},
 173         {Opt_err, NULL},
 174 };
 175
 176 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 177 {
 178         substring_t args[MAX_OPT_ARGS];
 179         char *p, *name;
 180         unsigned int opt;
 181
 182         if (!data)
 183                 return 0;
 184
 185         while ((p = strsep(&data, ","))) {
 186                 int token;
 187
 188                 if (!*p)
 189                         continue;
 190
 191                 token = match_token(p, tokens, args);
 192                 switch (token) {
 193                 case Opt_override_compr:
 194                         name = match_strdup(&args[0]);
 195
 196                         if (!name)
 197                                 return -ENOMEM;
 198                         if (!strcmp(name, "none"))
 199                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 200 #ifdef CONFIG_JFFS2_LZO
 201                         else if (!strcmp(name, "lzo"))
 202                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 203 #endif
 204 #ifdef CONFIG_JFFS2_ZLIB
 205                         else if (!strcmp(name, "zlib"))
 206                                 c->mount_opts.compr =
 207                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 208 #endif
 209                         else {
 210                                 pr_err("Error: unknown compressor \"%s\"\n",
 211                                        name);
 212                                 kfree(name);
 213                                 return -EINVAL;
 214                         }
 215                         kfree(name);
 216                         c->mount_opts.override_compr = true;
 217                         break;
 218                 case Opt_rp_size:
 219                         if (match_int(&args[0], &opt))
 220                                 return -EINVAL;
 221                         opt *= 1024;
 222                         if (opt > c->mtd->size) {
 223                                 pr_warn("Too large reserve pool specified, max "
 224                                         "is %llu KB\n", c->mtd->size / 1024);
 225                                 return -EINVAL;
 226                         }
 227                         c->mount_opts.rp_size = opt;
 228                         break;
 229                 default:
 230                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
 231                                p);
 232                         return -EINVAL;
 233                 }
 234         }
 235
 236         return 0;
 237 }
 238
 239 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 240 {
 241         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 242         int err;
 243
 244         sync_filesystem(sb);
 245         err = jffs2_parse_options(c, data);
 246         if (err)
 247                 return -EINVAL;
 248
 249         return jffs2_do_remount_fs(sb, flags, data);
 250 }
 251
 252 static const struct super_operations jffs2_super_operations =
 253 {
 254         .alloc_inode =  jffs2_alloc_inode,
 255         .free_inode =   jffs2_free_inode,
 256         .put_super =    jffs2_put_super,
 257         .statfs =       jffs2_statfs,
 258         .remount_fs =   jffs2_remount_fs,
 259         .evict_inode =  jffs2_evict_inode,
 260         .dirty_inode =  jffs2_dirty_inode,
 261         .show_options = jffs2_show_options,
 262         .sync_fs =      jffs2_sync_fs,
 263 };
 264
 265 /*
 266  * fill in the superblock
 267  */
 268 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 269 {
 270         struct jffs2_sb_info *c;
 271         int ret;
 272
 273         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 274                   " New superblock for device %d (\"%s\")\n",
 275                   sb->s_mtd->index, sb->s_mtd->name);
 276
 277         c = kzalloc(sizeof(*c), GFP_KERNEL);
 278         if (!c)
 279                 return -ENOMEM;
 280
 281         c->mtd = sb->s_mtd;
 282         c->os_priv = sb;
 283         sb->s_fs_info = c;
 284
 285         ret = jffs2_parse_options(c, data);
 286         if (ret)
 287                 return -EINVAL;
 288
 289         /* Initialize JFFS2 superblock locks, the further initialization will
 290          * be done later */
 291         mutex_init(&c->alloc_sem);
 292         mutex_init(&c->erase_free_sem);
 293         init_waitqueue_head(&c->erase_wait);
 294         init_waitqueue_head(&c->inocache_wq);
 295         spin_lock_init(&c->erase_completion_lock);
 296         spin_lock_init(&c->inocache_lock);
 297
 298         sb->s_op = &jffs2_super_operations;
 299         sb->s_export_op = &jffs2_export_ops;
 300         sb->s_flags = sb->s_flags | SB_NOATIME;
 301         sb->s_xattr = jffs2_xattr_handlers;
 302 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 303         sb->s_flags |= SB_POSIXACL;
 304 #endif
 305         ret = jffs2_do_fill_super(sb, data, silent);
 306         return ret;
 307 }
 308
 309 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
 310                         int flags, const char *dev_name,
 311                         void *data)
 312 {
 313         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
 314 }
 315
 316 static void jffs2_put_super (struct super_block *sb)
 317 {
 318         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 319
 320         jffs2_dbg(2, "%s()\n", __func__);
 321
 322         mutex_lock(&c->alloc_sem);
 323         jffs2_flush_wbuf_pad(c);
 324         mutex_unlock(&c->alloc_sem);
 325
 326         jffs2_sum_exit(c);
 327
 328         jffs2_free_ino_caches(c);
 329         jffs2_free_raw_node_refs(c);
 330         kvfree(c->blocks);
 331         jffs2_flash_cleanup(c);
 332         kfree(c->inocache_list);
 333         jffs2_clear_xattr_subsystem(c);
 334         mtd_sync(c->mtd);
 335         jffs2_dbg(1, "%s(): returning\n", __func__);
 336 }
 337
 338 static void jffs2_kill_sb(struct super_block *sb)
 339 {
 340         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 341         if (c && !sb_rdonly(sb))
 342                 jffs2_stop_garbage_collect_thread(c);
 343         kill_mtd_super(sb);
 344         kfree(c);
 345 }
 346
 347 static struct file_system_type jffs2_fs_type = {
 348         .owner =        THIS_MODULE,
 349         .name =         "jffs2",
 350         .mount =        jffs2_mount,
 351         .kill_sb =      jffs2_kill_sb,
 352 };
 353 MODULE_ALIAS_FS("jffs2");
 354
 355 static int __init init_jffs2_fs(void)
 356 {
 357         int ret;
 358
 359         /* Paranoia checks for on-medium structures. If we ask GCC
 360            to pack them with __attribute__((packed)) then it _also_
 361            assumes that they're not aligned -- so it emits crappy
 362            code on some architectures. Ideally we want an attribute
 363            which means just 'no padding', without the alignment
 364            thing. But GCC doesn't have that -- we have to just
 365            hope the structs are the right sizes, instead. */
 366         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 367         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 368         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 369         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 370
 371         pr_info("version 2.2."
 372 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 373                " (NAND)"
 374 #endif
 375 #ifdef CONFIG_JFFS2_SUMMARY
 376                " (SUMMARY) "
 377 #endif
 378                " © 2001-2006 Red Hat, Inc.\n");
 379
 380         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 381                                              sizeof(struct jffs2_inode_info),
 382                                              0, (SLAB_RECLAIM_ACCOUNT|
 383                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 384                                              jffs2_i_init_once);
 385         if (!jffs2_inode_cachep) {
 386                 pr_err("error: Failed to initialise inode cache\n");
 387                 return -ENOMEM;
 388         }
 389         ret = jffs2_compressors_init();
 390         if (ret) {
 391                 pr_err("error: Failed to initialise compressors\n");
 392                 goto out;
 393         }
 394         ret = jffs2_create_slab_caches();
 395         if (ret) {
 396                 pr_err("error: Failed to initialise slab caches\n");
 397                 goto out_compressors;
 398         }
 399         ret = register_filesystem(&jffs2_fs_type);
 400         if (ret) {
 401                 pr_err("error: Failed to register filesystem\n");
 402                 goto out_slab;
 403         }
 404         return 0;
 405
 406  out_slab:
 407         jffs2_destroy_slab_caches();
 408  out_compressors:
 409         jffs2_compressors_exit();
 410  out:
 411         kmem_cache_destroy(jffs2_inode_cachep);
 412         return ret;
 413 }
 414
 415 static void __exit exit_jffs2_fs(void)
 416 {
 417         unregister_filesystem(&jffs2_fs_type);
 418         jffs2_destroy_slab_caches();
 419         jffs2_compressors_exit();
 420
 421         /*
 422          * Make sure all delayed rcu free inodes are flushed before we
 423          * destroy cache.
 424          */
 425         rcu_barrier();
 426         kmem_cache_destroy(jffs2_inode_cachep);
 427 }
 428
 429 module_init(init_jffs2_fs);
 430 module_exit(exit_jffs2_fs);
 431
 432 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 433 MODULE_AUTHOR("Red Hat, Inc.");
 434 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 435                        // the sake of this tag. It's Free Software.