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 void jffs2_write_super(struct super_block *sb)
  67 {
  68         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  69
  70         lock_super(sb);
  71         sb->s_dirt = 0;
  72
  73         if (!(sb->s_flags & MS_RDONLY)) {
  74                 jffs2_dbg(1, "%s()\n", __func__);
  75                 jffs2_flush_wbuf_gc(c, 0);
  76         }
  77
  78         unlock_super(sb);
  79 }
  80
  81 static const char *jffs2_compr_name(unsigned int compr)
  82 {
  83         switch (compr) {
  84         case JFFS2_COMPR_MODE_NONE:
  85                 return "none";
  86 #ifdef CONFIG_JFFS2_LZO
  87         case JFFS2_COMPR_MODE_FORCELZO:
  88                 return "lzo";
  89 #endif
  90 #ifdef CONFIG_JFFS2_ZLIB
  91         case JFFS2_COMPR_MODE_FORCEZLIB:
  92                 return "zlib";
  93 #endif
  94         default:
  95                 /* should never happen; programmer error */
  96                 WARN_ON(1);
  97                 return "";
  98         }
  99 }
 100
 101 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
 102 {
 103         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
 104         struct jffs2_mount_opts *opts = &c->mount_opts;
 105
 106         if (opts->override_compr)
 107                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
 108
 109         return 0;
 110 }
 111
 112 static int jffs2_sync_fs(struct super_block *sb, int wait)
 113 {
 114         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 115
 116         jffs2_write_super(sb);
 117
 118         mutex_lock(&c->alloc_sem);
 119         jffs2_flush_wbuf_pad(c);
 120         mutex_unlock(&c->alloc_sem);
 121         return 0;
 122 }
 123
 124 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 125                                          uint32_t generation)
 126 {
 127         /* We don't care about i_generation. We'll destroy the flash
 128            before we start re-using inode numbers anyway. And even
 129            if that wasn't true, we'd have other problems...*/
 130         return jffs2_iget(sb, ino);
 131 }
 132
 133 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 134                                          int fh_len, int fh_type)
 135 {
 136         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 137                                     jffs2_nfs_get_inode);
 138 }
 139
 140 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 141                                          int fh_len, int fh_type)
 142 {
 143         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 144                                     jffs2_nfs_get_inode);
 145 }
 146
 147 static struct dentry *jffs2_get_parent(struct dentry *child)
 148 {
 149         struct jffs2_inode_info *f;
 150         uint32_t pino;
 151
 152         BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 153
 154         f = JFFS2_INODE_INFO(child->d_inode);
 155
 156         pino = f->inocache->pino_nlink;
 157
 158         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 159                     f->inocache->ino, pino);
 160
 161         return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 162 }
 163
 164 static const struct export_operations jffs2_export_ops = {
 165         .get_parent = jffs2_get_parent,
 166         .fh_to_dentry = jffs2_fh_to_dentry,
 167         .fh_to_parent = jffs2_fh_to_parent,
 168 };
 169
 170 /*
 171  * JFFS2 mount options.
 172  *
 173  * Opt_override_compr: override default compressor
 174  * Opt_err: just end of array marker
 175  */
 176 enum {
 177         Opt_override_compr,
 178         Opt_err,
 179 };
 180
 181 static const match_table_t tokens = {
 182         {Opt_override_compr, "compr=%s"},
 183         {Opt_err, NULL},
 184 };
 185
 186 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 187 {
 188         substring_t args[MAX_OPT_ARGS];
 189         char *p, *name;
 190
 191         if (!data)
 192                 return 0;
 193
 194         while ((p = strsep(&data, ","))) {
 195                 int token;
 196
 197                 if (!*p)
 198                         continue;
 199
 200                 token = match_token(p, tokens, args);
 201                 switch (token) {
 202                 case Opt_override_compr:
 203                         name = match_strdup(&args[0]);
 204
 205                         if (!name)
 206                                 return -ENOMEM;
 207                         if (!strcmp(name, "none"))
 208                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 209 #ifdef CONFIG_JFFS2_LZO
 210                         else if (!strcmp(name, "lzo"))
 211                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 212 #endif
 213 #ifdef CONFIG_JFFS2_ZLIB
 214                         else if (!strcmp(name, "zlib"))
 215                                 c->mount_opts.compr =
 216                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 217 #endif
 218                         else {
 219                                 pr_err("Error: unknown compressor \"%s\"\n",
 220                                        name);
 221                                 kfree(name);
 222                                 return -EINVAL;
 223                         }
 224                         kfree(name);
 225                         c->mount_opts.override_compr = true;
 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         .write_super =  jffs2_write_super,
 255         .statfs =       jffs2_statfs,
 256         .remount_fs =   jffs2_remount_fs,
 257         .evict_inode =  jffs2_evict_inode,
 258         .dirty_inode =  jffs2_dirty_inode,
 259         .show_options = jffs2_show_options,
 260         .sync_fs =      jffs2_sync_fs,
 261 };
 262
 263 /*
 264  * fill in the superblock
 265  */
 266 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 267 {
 268         struct jffs2_sb_info *c;
 269         int ret;
 270
 271         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 272                   " New superblock for device %d (\"%s\")\n",
 273                   sb->s_mtd->index, sb->s_mtd->name);
 274
 275         c = kzalloc(sizeof(*c), GFP_KERNEL);
 276         if (!c)
 277                 return -ENOMEM;
 278
 279         c->mtd = sb->s_mtd;
 280         c->os_priv = sb;
 281         sb->s_fs_info = c;
 282
 283         ret = jffs2_parse_options(c, data);
 284         if (ret) {
 285                 kfree(c);
 286                 return -EINVAL;
 287         }
 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 | MS_NOATIME;
 301         sb->s_xattr = jffs2_xattr_handlers;
 302 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 303         sb->s_flags |= MS_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         if (sb->s_dirt)
 323                 jffs2_write_super(sb);
 324
 325         mutex_lock(&c->alloc_sem);
 326         jffs2_flush_wbuf_pad(c);
 327         mutex_unlock(&c->alloc_sem);
 328
 329         jffs2_sum_exit(c);
 330
 331         jffs2_free_ino_caches(c);
 332         jffs2_free_raw_node_refs(c);
 333         if (jffs2_blocks_use_vmalloc(c))
 334                 vfree(c->blocks);
 335         else
 336                 kfree(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 (!(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         pr_info("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                 pr_err("error: Failed to initialise inode cache\n");
 392                 return -ENOMEM;
 393         }
 394         ret = jffs2_compressors_init();
 395         if (ret) {
 396                 pr_err("error: Failed to initialise compressors\n");
 397                 goto out;
 398         }
 399         ret = jffs2_create_slab_caches();
 400         if (ret) {
 401                 pr_err("error: Failed to initialise slab caches\n");
 402                 goto out_compressors;
 403         }
 404         ret = register_filesystem(&jffs2_fs_type);
 405         if (ret) {
 406                 pr_err("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.