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
  94         return 0;
  95 }
  96
  97 static int jffs2_sync_fs(struct super_block *sb, int wait)
  98 {
  99         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 100
 101         mutex_lock(&c->alloc_sem);
 102         jffs2_flush_wbuf_pad(c);
 103         mutex_unlock(&c->alloc_sem);
 104         return 0;
 105 }
 106
 107 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 108                                          uint32_t generation)
 109 {
 110         /* We don't care about i_generation. We'll destroy the flash
 111            before we start re-using inode numbers anyway. And even
 112            if that wasn't true, we'd have other problems...*/
 113         return jffs2_iget(sb, ino);
 114 }
 115
 116 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 117                                          int fh_len, int fh_type)
 118 {
 119         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 120                                     jffs2_nfs_get_inode);
 121 }
 122
 123 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 124                                          int fh_len, int fh_type)
 125 {
 126         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 127                                     jffs2_nfs_get_inode);
 128 }
 129
 130 static struct dentry *jffs2_get_parent(struct dentry *child)
 131 {
 132         struct jffs2_inode_info *f;
 133         uint32_t pino;
 134
 135         BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 136
 137         f = JFFS2_INODE_INFO(child->d_inode);
 138
 139         pino = f->inocache->pino_nlink;
 140
 141         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 142                     f->inocache->ino, pino);
 143
 144         return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 145 }
 146
 147 static const struct export_operations jffs2_export_ops = {
 148         .get_parent = jffs2_get_parent,
 149         .fh_to_dentry = jffs2_fh_to_dentry,
 150         .fh_to_parent = jffs2_fh_to_parent,
 151 };
 152
 153 /*
 154  * JFFS2 mount options.
 155  *
 156  * Opt_override_compr: override default compressor
 157  * Opt_err: just end of array marker
 158  */
 159 enum {
 160         Opt_override_compr,
 161         Opt_err,
 162 };
 163
 164 static const match_table_t tokens = {
 165         {Opt_override_compr, "compr=%s"},
 166         {Opt_err, NULL},
 167 };
 168
 169 static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
 170 {
 171         substring_t args[MAX_OPT_ARGS];
 172         char *p, *name;
 173
 174         if (!data)
 175                 return 0;
 176
 177         while ((p = strsep(&data, ","))) {
 178                 int token;
 179
 180                 if (!*p)
 181                         continue;
 182
 183                 token = match_token(p, tokens, args);
 184                 switch (token) {
 185                 case Opt_override_compr:
 186                         name = match_strdup(&args[0]);
 187
 188                         if (!name)
 189                                 return -ENOMEM;
 190                         if (!strcmp(name, "none"))
 191                                 c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
 192 #ifdef CONFIG_JFFS2_LZO
 193                         else if (!strcmp(name, "lzo"))
 194                                 c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
 195 #endif
 196 #ifdef CONFIG_JFFS2_ZLIB
 197                         else if (!strcmp(name, "zlib"))
 198                                 c->mount_opts.compr =
 199                                                 JFFS2_COMPR_MODE_FORCEZLIB;
 200 #endif
 201                         else {
 202                                 pr_err("Error: unknown compressor \"%s\"\n",
 203                                        name);
 204                                 kfree(name);
 205                                 return -EINVAL;
 206                         }
 207                         kfree(name);
 208                         c->mount_opts.override_compr = true;
 209                         break;
 210                 default:
 211                         pr_err("Error: unrecognized mount option '%s' or missing value\n",
 212                                p);
 213                         return -EINVAL;
 214                 }
 215         }
 216
 217         return 0;
 218 }
 219
 220 static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
 221 {
 222         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 223         int err;
 224
 225         err = jffs2_parse_options(c, data);
 226         if (err)
 227                 return -EINVAL;
 228
 229         return jffs2_do_remount_fs(sb, flags, data);
 230 }
 231
 232 static const struct super_operations jffs2_super_operations =
 233 {
 234         .alloc_inode =  jffs2_alloc_inode,
 235         .destroy_inode =jffs2_destroy_inode,
 236         .put_super =    jffs2_put_super,
 237         .statfs =       jffs2_statfs,
 238         .remount_fs =   jffs2_remount_fs,
 239         .evict_inode =  jffs2_evict_inode,
 240         .dirty_inode =  jffs2_dirty_inode,
 241         .show_options = jffs2_show_options,
 242         .sync_fs =      jffs2_sync_fs,
 243 };
 244
 245 /*
 246  * fill in the superblock
 247  */
 248 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 249 {
 250         struct jffs2_sb_info *c;
 251         int ret;
 252
 253         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 254                   " New superblock for device %d (\"%s\")\n",
 255                   sb->s_mtd->index, sb->s_mtd->name);
 256
 257         c = kzalloc(sizeof(*c), GFP_KERNEL);
 258         if (!c)
 259                 return -ENOMEM;
 260
 261         c->mtd = sb->s_mtd;
 262         c->os_priv = sb;
 263         sb->s_fs_info = c;
 264
 265         ret = jffs2_parse_options(c, data);
 266         if (ret) {
 267                 kfree(c);
 268                 return -EINVAL;
 269         }
 270
 271         /* Initialize JFFS2 superblock locks, the further initialization will
 272          * be done later */
 273         mutex_init(&c->alloc_sem);
 274         mutex_init(&c->erase_free_sem);
 275         init_waitqueue_head(&c->erase_wait);
 276         init_waitqueue_head(&c->inocache_wq);
 277         spin_lock_init(&c->erase_completion_lock);
 278         spin_lock_init(&c->inocache_lock);
 279
 280         sb->s_op = &jffs2_super_operations;
 281         sb->s_export_op = &jffs2_export_ops;
 282         sb->s_flags = sb->s_flags | MS_NOATIME;
 283         sb->s_xattr = jffs2_xattr_handlers;
 284 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 285         sb->s_flags |= MS_POSIXACL;
 286 #endif
 287         ret = jffs2_do_fill_super(sb, data, silent);
 288         return ret;
 289 }
 290
 291 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
 292                         int flags, const char *dev_name,
 293                         void *data)
 294 {
 295         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
 296 }
 297
 298 static void jffs2_put_super (struct super_block *sb)
 299 {
 300         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 301
 302         jffs2_dbg(2, "%s()\n", __func__);
 303
 304         mutex_lock(&c->alloc_sem);
 305         jffs2_flush_wbuf_pad(c);
 306         mutex_unlock(&c->alloc_sem);
 307
 308         jffs2_sum_exit(c);
 309
 310         jffs2_free_ino_caches(c);
 311         jffs2_free_raw_node_refs(c);
 312         if (jffs2_blocks_use_vmalloc(c))
 313                 vfree(c->blocks);
 314         else
 315                 kfree(c->blocks);
 316         jffs2_flash_cleanup(c);
 317         kfree(c->inocache_list);
 318         jffs2_clear_xattr_subsystem(c);
 319         mtd_sync(c->mtd);
 320         jffs2_dbg(1, "%s(): returning\n", __func__);
 321 }
 322
 323 static void jffs2_kill_sb(struct super_block *sb)
 324 {
 325         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 326         if (!(sb->s_flags & MS_RDONLY))
 327                 jffs2_stop_garbage_collect_thread(c);
 328         kill_mtd_super(sb);
 329         kfree(c);
 330 }
 331
 332 static struct file_system_type jffs2_fs_type = {
 333         .owner =        THIS_MODULE,
 334         .name =         "jffs2",
 335         .mount =        jffs2_mount,
 336         .kill_sb =      jffs2_kill_sb,
 337 };
 338
 339 static int __init init_jffs2_fs(void)
 340 {
 341         int ret;
 342
 343         /* Paranoia checks for on-medium structures. If we ask GCC
 344            to pack them with __attribute__((packed)) then it _also_
 345            assumes that they're not aligned -- so it emits crappy
 346            code on some architectures. Ideally we want an attribute
 347            which means just 'no padding', without the alignment
 348            thing. But GCC doesn't have that -- we have to just
 349            hope the structs are the right sizes, instead. */
 350         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 351         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 352         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 353         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 354
 355         pr_info("version 2.2."
 356 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 357                " (NAND)"
 358 #endif
 359 #ifdef CONFIG_JFFS2_SUMMARY
 360                " (SUMMARY) "
 361 #endif
 362                " © 2001-2006 Red Hat, Inc.\n");
 363
 364         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 365                                              sizeof(struct jffs2_inode_info),
 366                                              0, (SLAB_RECLAIM_ACCOUNT|
 367                                                 SLAB_MEM_SPREAD),
 368                                              jffs2_i_init_once);
 369         if (!jffs2_inode_cachep) {
 370                 pr_err("error: Failed to initialise inode cache\n");
 371                 return -ENOMEM;
 372         }
 373         ret = jffs2_compressors_init();
 374         if (ret) {
 375                 pr_err("error: Failed to initialise compressors\n");
 376                 goto out;
 377         }
 378         ret = jffs2_create_slab_caches();
 379         if (ret) {
 380                 pr_err("error: Failed to initialise slab caches\n");
 381                 goto out_compressors;
 382         }
 383         ret = register_filesystem(&jffs2_fs_type);
 384         if (ret) {
 385                 pr_err("error: Failed to register filesystem\n");
 386                 goto out_slab;
 387         }
 388         return 0;
 389
 390  out_slab:
 391         jffs2_destroy_slab_caches();
 392  out_compressors:
 393         jffs2_compressors_exit();
 394  out:
 395         kmem_cache_destroy(jffs2_inode_cachep);
 396         return ret;
 397 }
 398
 399 static void __exit exit_jffs2_fs(void)
 400 {
 401         unregister_filesystem(&jffs2_fs_type);
 402         jffs2_destroy_slab_caches();
 403         jffs2_compressors_exit();
 404         kmem_cache_destroy(jffs2_inode_cachep);
 405 }
 406
 407 module_init(init_jffs2_fs);
 408 module_exit(exit_jffs2_fs);
 409
 410 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 411 MODULE_AUTHOR("Red Hat, Inc.");
 412 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 413                        // the sake of this tag. It's Free Software.