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/fs_context.h>
  23 #include <linux/fs_parser.h>
  24 #include <linux/jffs2.h>
  25 #include <linux/pagemap.h>
  26 #include <linux/mtd/super.h>
  27 #include <linux/ctype.h>
  28 #include <linux/namei.h>
  29 #include <linux/seq_file.h>
  30 #include <linux/exportfs.h>
  31 #include "compr.h"
  32 #include "nodelist.h"
  33
  34 static void jffs2_put_super(struct super_block *);
  35
  36 static struct kmem_cache *jffs2_inode_cachep;
  37
  38 static struct inode *jffs2_alloc_inode(struct super_block *sb)
  39 {
  40         struct jffs2_inode_info *f;
  41
  42         f = alloc_inode_sb(sb, jffs2_inode_cachep, GFP_KERNEL);
  43         if (!f)
  44                 return NULL;
  45         return &f->vfs_inode;
  46 }
  47
  48 static void jffs2_free_inode(struct inode *inode)
  49 {
  50         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
  51
  52         kfree(f->target);
  53         kmem_cache_free(jffs2_inode_cachep, f);
  54 }
  55
  56 static void jffs2_i_init_once(void *foo)
  57 {
  58         struct jffs2_inode_info *f = foo;
  59
  60         mutex_init(&f->sem);
  61         f->target = NULL;
  62         inode_init_once(&f->vfs_inode);
  63 }
  64
  65 static const char *jffs2_compr_name(unsigned int compr)
  66 {
  67         switch (compr) {
  68         case JFFS2_COMPR_MODE_NONE:
  69                 return "none";
  70 #ifdef CONFIG_JFFS2_LZO
  71         case JFFS2_COMPR_MODE_FORCELZO:
  72                 return "lzo";
  73 #endif
  74 #ifdef CONFIG_JFFS2_ZLIB
  75         case JFFS2_COMPR_MODE_FORCEZLIB:
  76                 return "zlib";
  77 #endif
  78         default:
  79                 /* should never happen; programmer error */
  80                 WARN_ON(1);
  81                 return "";
  82         }
  83 }
  84
  85 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
  86 {
  87         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
  88         struct jffs2_mount_opts *opts = &c->mount_opts;
  89
  90         if (opts->override_compr)
  91                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
  92         if (opts->set_rp_size)
  93                 seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
  94
  95         return 0;
  96 }
  97
  98 static int jffs2_sync_fs(struct super_block *sb, int wait)
  99 {
 100         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 101
 102 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 103         if (jffs2_is_writebuffered(c))
 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(child->d_sb, pino));
 151 }
 152
 153 static const struct export_operations jffs2_export_ops = {
 154         .encode_fh = generic_encode_ino32_fh,
 155         .get_parent = jffs2_get_parent,
 156         .fh_to_dentry = jffs2_fh_to_dentry,
 157         .fh_to_parent = jffs2_fh_to_parent,
 158 };
 159
 160 /*
 161  * JFFS2 mount options.
 162  *
 163  * Opt_source: The source device
 164  * Opt_override_compr: override default compressor
 165  * Opt_rp_size: size of reserved pool in KiB
 166  */
 167 enum {
 168         Opt_override_compr,
 169         Opt_rp_size,
 170 };
 171
 172 static const struct constant_table jffs2_param_compr[] = {
 173         {"none",        JFFS2_COMPR_MODE_NONE },
 174 #ifdef CONFIG_JFFS2_LZO
 175         {"lzo",         JFFS2_COMPR_MODE_FORCELZO },
 176 #endif
 177 #ifdef CONFIG_JFFS2_ZLIB
 178         {"zlib",        JFFS2_COMPR_MODE_FORCEZLIB },
 179 #endif
 180         {}
 181 };
 182
 183 static const struct fs_parameter_spec jffs2_fs_parameters[] = {
 184         fsparam_enum    ("compr",       Opt_override_compr, jffs2_param_compr),
 185         fsparam_u32     ("rp_size",     Opt_rp_size),
 186         {}
 187 };
 188
 189 static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
 190 {
 191         struct fs_parse_result result;
 192         struct jffs2_sb_info *c = fc->s_fs_info;
 193         int opt;
 194
 195         opt = fs_parse(fc, jffs2_fs_parameters, param, &result);
 196         if (opt < 0)
 197                 return opt;
 198
 199         switch (opt) {
 200         case Opt_override_compr:
 201                 c->mount_opts.compr = result.uint_32;
 202                 c->mount_opts.override_compr = true;
 203                 break;
 204         case Opt_rp_size:
 205                 if (result.uint_32 > UINT_MAX / 1024)
 206                         return invalf(fc, "jffs2: rp_size unrepresentable");
 207                 c->mount_opts.rp_size = result.uint_32 * 1024;
 208                 c->mount_opts.set_rp_size = true;
 209                 break;
 210         default:
 211                 return -EINVAL;
 212         }
 213
 214         return 0;
 215 }
 216
 217 static inline void jffs2_update_mount_opts(struct fs_context *fc)
 218 {
 219         struct jffs2_sb_info *new_c = fc->s_fs_info;
 220         struct jffs2_sb_info *c = JFFS2_SB_INFO(fc->root->d_sb);
 221
 222         mutex_lock(&c->alloc_sem);
 223         if (new_c->mount_opts.override_compr) {
 224                 c->mount_opts.override_compr = new_c->mount_opts.override_compr;
 225                 c->mount_opts.compr = new_c->mount_opts.compr;
 226         }
 227         if (new_c->mount_opts.set_rp_size) {
 228                 c->mount_opts.set_rp_size = new_c->mount_opts.set_rp_size;
 229                 c->mount_opts.rp_size = new_c->mount_opts.rp_size;
 230         }
 231         mutex_unlock(&c->alloc_sem);
 232 }
 233
 234 static int jffs2_reconfigure(struct fs_context *fc)
 235 {
 236         struct super_block *sb = fc->root->d_sb;
 237
 238         sync_filesystem(sb);
 239         jffs2_update_mount_opts(fc);
 240
 241         return jffs2_do_remount_fs(sb, fc);
 242 }
 243
 244 static const struct super_operations jffs2_super_operations =
 245 {
 246         .alloc_inode =  jffs2_alloc_inode,
 247         .free_inode =   jffs2_free_inode,
 248         .put_super =    jffs2_put_super,
 249         .statfs =       jffs2_statfs,
 250         .evict_inode =  jffs2_evict_inode,
 251         .dirty_inode =  jffs2_dirty_inode,
 252         .show_options = jffs2_show_options,
 253         .sync_fs =      jffs2_sync_fs,
 254 };
 255
 256 /*
 257  * fill in the superblock
 258  */
 259 static int jffs2_fill_super(struct super_block *sb, struct fs_context *fc)
 260 {
 261         struct jffs2_sb_info *c = sb->s_fs_info;
 262
 263         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 264                   " New superblock for device %d (\"%s\")\n",
 265                   sb->s_mtd->index, sb->s_mtd->name);
 266
 267         c->mtd = sb->s_mtd;
 268         c->os_priv = sb;
 269
 270         if (c->mount_opts.rp_size > c->mtd->size)
 271                 return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
 272                               c->mtd->size / 1024);
 273
 274         /* Initialize JFFS2 superblock locks, the further initialization will
 275          * be done later */
 276         mutex_init(&c->alloc_sem);
 277         mutex_init(&c->erase_free_sem);
 278         init_waitqueue_head(&c->erase_wait);
 279         init_waitqueue_head(&c->inocache_wq);
 280         spin_lock_init(&c->erase_completion_lock);
 281         spin_lock_init(&c->inocache_lock);
 282
 283         sb->s_op = &jffs2_super_operations;
 284         sb->s_export_op = &jffs2_export_ops;
 285         sb->s_flags = sb->s_flags | SB_NOATIME;
 286         sb->s_xattr = jffs2_xattr_handlers;
 287 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 288         sb->s_flags |= SB_POSIXACL;
 289 #endif
 290         return jffs2_do_fill_super(sb, fc);
 291 }
 292
 293 static int jffs2_get_tree(struct fs_context *fc)
 294 {
 295         return get_tree_mtd(fc, jffs2_fill_super);
 296 }
 297
 298 static void jffs2_free_fc(struct fs_context *fc)
 299 {
 300         kfree(fc->s_fs_info);
 301 }
 302
 303 static const struct fs_context_operations jffs2_context_ops = {
 304         .free           = jffs2_free_fc,
 305         .parse_param    = jffs2_parse_param,
 306         .get_tree       = jffs2_get_tree,
 307         .reconfigure    = jffs2_reconfigure,
 308 };
 309
 310 static int jffs2_init_fs_context(struct fs_context *fc)
 311 {
 312         struct jffs2_sb_info *ctx;
 313
 314         ctx = kzalloc(sizeof(struct jffs2_sb_info), GFP_KERNEL);
 315         if (!ctx)
 316                 return -ENOMEM;
 317
 318         fc->s_fs_info = ctx;
 319         fc->ops = &jffs2_context_ops;
 320         return 0;
 321 }
 322
 323 static void jffs2_put_super (struct super_block *sb)
 324 {
 325         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 326
 327         jffs2_dbg(2, "%s()\n", __func__);
 328
 329         mutex_lock(&c->alloc_sem);
 330         jffs2_flush_wbuf_pad(c);
 331         mutex_unlock(&c->alloc_sem);
 332
 333         jffs2_sum_exit(c);
 334
 335         jffs2_free_ino_caches(c);
 336         jffs2_free_raw_node_refs(c);
 337         kvfree(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 (c && !sb_rdonly(sb))
 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         .init_fs_context = jffs2_init_fs_context,
 358         .parameters =   jffs2_fs_parameters,
 359         .kill_sb =      jffs2_kill_sb,
 360 };
 361 MODULE_ALIAS_FS("jffs2");
 362
 363 static int __init init_jffs2_fs(void)
 364 {
 365         int ret;
 366
 367         /* Paranoia checks for on-medium structures. If we ask GCC
 368            to pack them with __attribute__((packed)) then it _also_
 369            assumes that they're not aligned -- so it emits crappy
 370            code on some architectures. Ideally we want an attribute
 371            which means just 'no padding', without the alignment
 372            thing. But GCC doesn't have that -- we have to just
 373            hope the structs are the right sizes, instead. */
 374         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 375         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 376         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 377         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 378
 379         pr_info("version 2.2."
 380 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 381                " (NAND)"
 382 #endif
 383 #ifdef CONFIG_JFFS2_SUMMARY
 384                " (SUMMARY) "
 385 #endif
 386                " © 2001-2006 Red Hat, Inc.\n");
 387
 388         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 389                                              sizeof(struct jffs2_inode_info),
 390                                              0, (SLAB_RECLAIM_ACCOUNT|
 391                                                 SLAB_ACCOUNT),
 392                                              jffs2_i_init_once);
 393         if (!jffs2_inode_cachep) {
 394                 pr_err("error: Failed to initialise inode cache\n");
 395                 return -ENOMEM;
 396         }
 397         ret = jffs2_compressors_init();
 398         if (ret) {
 399                 pr_err("error: Failed to initialise compressors\n");
 400                 goto out;
 401         }
 402         ret = jffs2_create_slab_caches();
 403         if (ret) {
 404                 pr_err("error: Failed to initialise slab caches\n");
 405                 goto out_compressors;
 406         }
 407         ret = register_filesystem(&jffs2_fs_type);
 408         if (ret) {
 409                 pr_err("error: Failed to register filesystem\n");
 410                 goto out_slab;
 411         }
 412         return 0;
 413
 414  out_slab:
 415         jffs2_destroy_slab_caches();
 416  out_compressors:
 417         jffs2_compressors_exit();
 418  out:
 419         kmem_cache_destroy(jffs2_inode_cachep);
 420         return ret;
 421 }
 422
 423 static void __exit exit_jffs2_fs(void)
 424 {
 425         unregister_filesystem(&jffs2_fs_type);
 426         jffs2_destroy_slab_caches();
 427         jffs2_compressors_exit();
 428
 429         /*
 430          * Make sure all delayed rcu free inodes are flushed before we
 431          * destroy cache.
 432          */
 433         rcu_barrier();
 434         kmem_cache_destroy(jffs2_inode_cachep);
 435 }
 436
 437 module_init(init_jffs2_fs);
 438 module_exit(exit_jffs2_fs);
 439
 440 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 441 MODULE_AUTHOR("Red Hat, Inc.");
 442 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 443                        // the sake of this tag. It's Free Software.