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 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/init.h>
  16 #include <linux/list.h>
  17 #include <linux/fs.h>
  18 #include <linux/err.h>
  19 #include <linux/mount.h>
  20 #include <linux/parser.h>
  21 #include <linux/jffs2.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/mtd/super.h>
  24 #include <linux/ctype.h>
  25 #include <linux/namei.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/exportfs.h>
  28 #include "compr.h"
  29 #include "nodelist.h"
  30
  31 static void jffs2_put_super(struct super_block *);
  32
  33 static struct kmem_cache *jffs2_inode_cachep;
  34
  35 static struct inode *jffs2_alloc_inode(struct super_block *sb)
  36 {
  37         struct jffs2_inode_info *f;
  38
  39         f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
  40         if (!f)
  41                 return NULL;
  42         return &f->vfs_inode;
  43 }
  44
  45 static void jffs2_i_callback(struct rcu_head *head)
  46 {
  47         struct inode *inode = container_of(head, struct inode, i_rcu);
  48         INIT_LIST_HEAD(&inode->i_dentry);
  49         kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  50 }
  51
  52 static void jffs2_destroy_inode(struct inode *inode)
  53 {
  54         call_rcu(&inode->i_rcu, jffs2_i_callback);
  55 }
  56
  57 static void jffs2_i_init_once(void *foo)
  58 {
  59         struct jffs2_inode_info *f = foo;
  60
  61         mutex_init(&f->sem);
  62         inode_init_once(&f->vfs_inode);
  63 }
  64
  65 static void jffs2_write_super(struct super_block *sb)
  66 {
  67         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  68
  69         lock_super(sb);
  70         sb->s_dirt = 0;
  71
  72         if (!(sb->s_flags & MS_RDONLY)) {
  73                 D1(printk(KERN_DEBUG "jffs2_write_super()\n"));
  74                 jffs2_flush_wbuf_gc(c, 0);
  75         }
  76
  77         unlock_super(sb);
  78 }
  79
  80 static const char *jffs2_compr_name(unsigned int compr)
  81 {
  82         switch (compr) {
  83         case JFFS2_COMPR_MODE_NONE:
  84                 return "none";
  85 #ifdef CONFIG_JFFS2_LZO
  86         case JFFS2_COMPR_MODE_FORCELZO:
  87                 return "lzo";
  88 #endif
  89 #ifdef CONFIG_JFFS2_ZLIB
  90         case JFFS2_COMPR_MODE_FORCEZLIB:
  91                 return "zlib";
  92 #endif
  93         default:
  94                 /* should never happen; programmer error */
  95                 WARN_ON(1);
  96                 return "";
  97         }
  98 }
  99
 100 static int jffs2_show_options(struct seq_file *s, struct vfsmount *mnt)
 101 {
 102         struct jffs2_sb_info *c = JFFS2_SB_INFO(mnt->mnt_sb);
 103         struct jffs2_mount_opts *opts = &c->mount_opts;
 104
 105         if (opts->override_compr)
 106                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
 107
 108         return 0;
 109 }
 110
 111 static int jffs2_sync_fs(struct super_block *sb, int wait)
 112 {
 113         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 114
 115         jffs2_write_super(sb);
 116
 117         mutex_lock(&c->alloc_sem);
 118         jffs2_flush_wbuf_pad(c);
 119         mutex_unlock(&c->alloc_sem);
 120         return 0;
 121 }
 122
 123 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 124                                          uint32_t generation)
 125 {
 126         /* We don't care about i_generation. We'll destroy the flash
 127            before we start re-using inode numbers anyway. And even
 128            if that wasn't true, we'd have other problems...*/
 129         return jffs2_iget(sb, ino);
 130 }
 131
 132 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 133                                          int fh_len, int fh_type)
 134 {
 135         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 136                                     jffs2_nfs_get_inode);
 137 }
 138
 139 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 140                                          int fh_len, int fh_type)
 141 {
 142         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 143                                     jffs2_nfs_get_inode);
 144 }
 145
 146 static struct dentry *jffs2_get_parent(struct dentry *child)
 147 {
 148         struct jffs2_inode_info *f;
 149         uint32_t pino;
 150
 151         BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 152
 153         f = JFFS2_INODE_INFO(child->d_inode);
 154
 155         pino = f->inocache->pino_nlink;
 156
 157         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 158                     f->inocache->ino, pino);
 159
 160         return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 161 }
 162
 163 static const struct export_operations jffs2_export_ops = {
 164         .get_parent = jffs2_get_parent,
 165         .fh_to_dentry = jffs2_fh_to_dentry,
 166         .fh_to_parent = jffs2_fh_to_parent,
 167 };
 168
 169 /*
 170  * JFFS2 mount options.
 171  *
 172  * Opt_override_compr: override default compressor
 173  * Opt_err: just end of array marker
 174  */
 175 enum {
 176         Opt_override_compr,
 177         Opt_err,
 178 };
 179
 180 static const match_table_t tokens = {
 181         {Opt_override_compr, "compr=%s"},
 182         {Opt_err, NULL},
 183 };
 184
 185 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 186 {
 187         substring_t args[MAX_OPT_ARGS];
 188         char *p, *name;
 189
 190         if (!data)
 191                 return 0;
 192
 193         while ((p = strsep(&data, ","))) {
 194                 int token;
 195
 196                 if (!*p)
 197                         continue;
 198
 199                 token = match_token(p, tokens, args);
 200                 switch (token) {
 201                 case Opt_override_compr:
 202                         name = match_strdup(&args[0]);
 203
 204                         if (!name)
 205                                 return -ENOMEM;
 206                         if (!strcmp(name, "none"))
 207                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 208 #ifdef CONFIG_JFFS2_LZO
 209                         else if (!strcmp(name, "lzo"))
 210                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 211 #endif
 212 #ifdef CONFIG_JFFS2_ZLIB
 213                         else if (!strcmp(name, "zlib"))
 214                                 c->mount_opts.compr =
 215                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 216 #endif
 217                         else {
 218                                 printk(KERN_ERR "JFFS2 Error: unknown compressor \"%s\"",
 219                                                 name);
 220                                 kfree(name);
 221                                 return -EINVAL;
 222                         }
 223                         kfree(name);
 224                         c->mount_opts.override_compr = true;
 225                         break;
 226                 default:
 227                         printk(KERN_ERR "JFFS2 Error: unrecognized mount option '%s' or missing value\n",
 228                                         p);
 229                         return -EINVAL;
 230                 }
 231         }
 232
 233         return 0;
 234 }
 235
 236 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 237 {
 238         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 239         int err;
 240
 241         err = jffs2_parse_options(c, data);
 242         if (err)
 243                 return -EINVAL;
 244
 245         return jffs2_do_remount_fs(sb, flags, data);
 246 }
 247
 248 static const struct super_operations jffs2_super_operations =
 249 {
 250         .alloc_inode =  jffs2_alloc_inode,
 251         .destroy_inode =jffs2_destroy_inode,
 252         .put_super =    jffs2_put_super,
 253         .write_super =  jffs2_write_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         D1(printk(KERN_DEBUG "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         D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 320
 321         if (sb->s_dirt)
 322                 jffs2_write_super(sb);
 323
 324         mutex_lock(&c->alloc_sem);
 325         jffs2_flush_wbuf_pad(c);
 326         mutex_unlock(&c->alloc_sem);
 327
 328         jffs2_sum_exit(c);
 329
 330         jffs2_free_ino_caches(c);
 331         jffs2_free_raw_node_refs(c);
 332         if (jffs2_blocks_use_vmalloc(c))
 333                 vfree(c->blocks);
 334         else
 335                 kfree(c->blocks);
 336         jffs2_flash_cleanup(c);
 337         kfree(c->inocache_list);
 338         jffs2_clear_xattr_subsystem(c);
 339         if (c->mtd->sync)
 340                 c->mtd->sync(c->mtd);
 341
 342         D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 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
 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         printk(KERN_INFO "JFFS2 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),
 390                                              jffs2_i_init_once);
 391         if (!jffs2_inode_cachep) {
 392                 printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 393                 return -ENOMEM;
 394         }
 395         ret = jffs2_compressors_init();
 396         if (ret) {
 397                 printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
 398                 goto out;
 399         }
 400         ret = jffs2_create_slab_caches();
 401         if (ret) {
 402                 printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 403                 goto out_compressors;
 404         }
 405         ret = register_filesystem(&jffs2_fs_type);
 406         if (ret) {
 407                 printk(KERN_ERR "JFFS2 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         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.