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