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 = kmem_cache_alloc(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         inode_init_once(&f->vfs_inode);
  62 }
  63
  64 static const char *jffs2_compr_name(unsigned int compr)
  65 {
  66         switch (compr) {
  67         case JFFS2_COMPR_MODE_NONE:
  68                 return "none";
  69 #ifdef CONFIG_JFFS2_LZO
  70         case JFFS2_COMPR_MODE_FORCELZO:
  71                 return "lzo";
  72 #endif
  73 #ifdef CONFIG_JFFS2_ZLIB
  74         case JFFS2_COMPR_MODE_FORCEZLIB:
  75                 return "zlib";
  76 #endif
  77         default:
  78                 /* should never happen; programmer error */
  79                 WARN_ON(1);
  80                 return "";
  81         }
  82 }
  83
  84 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
  85 {
  86         struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
  87         struct jffs2_mount_opts *opts = &c->mount_opts;
  88
  89         if (opts->override_compr)
  90                 seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
  91         if (opts->set_rp_size)
  92                 seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
  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 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 102         if (jffs2_is_writebuffered(c))
 103                 cancel_delayed_work_sync(&c->wbuf_dwork);
 104 #endif
 105
 106         mutex_lock(&c->alloc_sem);
 107         jffs2_flush_wbuf_pad(c);
 108         mutex_unlock(&c->alloc_sem);
 109         return 0;
 110 }
 111
 112 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 113                                          uint32_t generation)
 114 {
 115         /* We don't care about i_generation. We'll destroy the flash
 116            before we start re-using inode numbers anyway. And even
 117            if that wasn't true, we'd have other problems...*/
 118         return jffs2_iget(sb, ino);
 119 }
 120
 121 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 122                                          int fh_len, int fh_type)
 123 {
 124         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 125                                     jffs2_nfs_get_inode);
 126 }
 127
 128 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 129                                          int fh_len, int fh_type)
 130 {
 131         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 132                                     jffs2_nfs_get_inode);
 133 }
 134
 135 static struct dentry *jffs2_get_parent(struct dentry *child)
 136 {
 137         struct jffs2_inode_info *f;
 138         uint32_t pino;
 139
 140         BUG_ON(!d_is_dir(child));
 141
 142         f = JFFS2_INODE_INFO(d_inode(child));
 143
 144         pino = f->inocache->pino_nlink;
 145
 146         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 147                     f->inocache->ino, pino);
 148
 149         return d_obtain_alias(jffs2_iget(child->d_sb, pino));
 150 }
 151
 152 static const struct export_operations jffs2_export_ops = {
 153         .get_parent = jffs2_get_parent,
 154         .fh_to_dentry = jffs2_fh_to_dentry,
 155         .fh_to_parent = jffs2_fh_to_parent,
 156 };
 157
 158 /*
 159  * JFFS2 mount options.
 160  *
 161  * Opt_source: The source device
 162  * Opt_override_compr: override default compressor
 163  * Opt_rp_size: size of reserved pool in KiB
 164  */
 165 enum {
 166         Opt_override_compr,
 167         Opt_rp_size,
 168 };
 169
 170 static const struct constant_table jffs2_param_compr[] = {
 171         {"none",        JFFS2_COMPR_MODE_NONE },
 172 #ifdef CONFIG_JFFS2_LZO
 173         {"lzo",         JFFS2_COMPR_MODE_FORCELZO },
 174 #endif
 175 #ifdef CONFIG_JFFS2_ZLIB
 176         {"zlib",        JFFS2_COMPR_MODE_FORCEZLIB },
 177 #endif
 178         {}
 179 };
 180
 181 static const struct fs_parameter_spec jffs2_fs_parameters[] = {
 182         fsparam_enum    ("compr",       Opt_override_compr, jffs2_param_compr),
 183         fsparam_u32     ("rp_size",     Opt_rp_size),
 184         {}
 185 };
 186
 187 static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
 188 {
 189         struct fs_parse_result result;
 190         struct jffs2_sb_info *c = fc->s_fs_info;
 191         int opt;
 192
 193         opt = fs_parse(fc, jffs2_fs_parameters, param, &result);
 194         if (opt < 0)
 195                 return opt;
 196
 197         switch (opt) {
 198         case Opt_override_compr:
 199                 c->mount_opts.compr = result.uint_32;
 200                 c->mount_opts.override_compr = true;
 201                 break;
 202         case Opt_rp_size:
 203                 if (result.uint_32 > UINT_MAX / 1024)
 204                         return invalf(fc, "jffs2: rp_size unrepresentable");
 205                 c->mount_opts.rp_size = result.uint_32 * 1024;
 206                 c->mount_opts.set_rp_size = true;
 207                 break;
 208         default:
 209                 return -EINVAL;
 210         }
 211
 212         return 0;
 213 }
 214
 215 static inline void jffs2_update_mount_opts(struct fs_context *fc)
 216 {
 217         struct jffs2_sb_info *new_c = fc->s_fs_info;
 218         struct jffs2_sb_info *c = JFFS2_SB_INFO(fc->root->d_sb);
 219
 220         mutex_lock(&c->alloc_sem);
 221         if (new_c->mount_opts.override_compr) {
 222                 c->mount_opts.override_compr = new_c->mount_opts.override_compr;
 223                 c->mount_opts.compr = new_c->mount_opts.compr;
 224         }
 225         if (new_c->mount_opts.set_rp_size) {
 226                 c->mount_opts.set_rp_size = new_c->mount_opts.set_rp_size;
 227                 c->mount_opts.rp_size = new_c->mount_opts.rp_size;
 228         }
 229         mutex_unlock(&c->alloc_sem);
 230 }
 231
 232 static int jffs2_reconfigure(struct fs_context *fc)
 233 {
 234         struct super_block *sb = fc->root->d_sb;
 235
 236         sync_filesystem(sb);
 237         jffs2_update_mount_opts(fc);
 238
 239         return jffs2_do_remount_fs(sb, fc);
 240 }
 241
 242 static const struct super_operations jffs2_super_operations =
 243 {
 244         .alloc_inode =  jffs2_alloc_inode,
 245         .free_inode =   jffs2_free_inode,
 246         .put_super =    jffs2_put_super,
 247         .statfs =       jffs2_statfs,
 248         .evict_inode =  jffs2_evict_inode,
 249         .dirty_inode =  jffs2_dirty_inode,
 250         .show_options = jffs2_show_options,
 251         .sync_fs =      jffs2_sync_fs,
 252 };
 253
 254 /*
 255  * fill in the superblock
 256  */
 257 static int jffs2_fill_super(struct super_block *sb, struct fs_context *fc)
 258 {
 259         struct jffs2_sb_info *c = sb->s_fs_info;
 260
 261         jffs2_dbg(1, "jffs2_get_sb_mtd():"
 262                   " New superblock for device %d (\"%s\")\n",
 263                   sb->s_mtd->index, sb->s_mtd->name);
 264
 265         c->mtd = sb->s_mtd;
 266         c->os_priv = sb;
 267
 268         if (c->mount_opts.rp_size > c->mtd->size)
 269                 return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
 270                               c->mtd->size / 1024);
 271
 272         /* Initialize JFFS2 superblock locks, the further initialization will
 273          * be done later */
 274         mutex_init(&c->alloc_sem);
 275         mutex_init(&c->erase_free_sem);
 276         init_waitqueue_head(&c->erase_wait);
 277         init_waitqueue_head(&c->inocache_wq);
 278         spin_lock_init(&c->erase_completion_lock);
 279         spin_lock_init(&c->inocache_lock);
 280
 281         sb->s_op = &jffs2_super_operations;
 282         sb->s_export_op = &jffs2_export_ops;
 283         sb->s_flags = sb->s_flags | SB_NOATIME;
 284         sb->s_xattr = jffs2_xattr_handlers;
 285 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 286         sb->s_flags |= SB_POSIXACL;
 287 #endif
 288         return jffs2_do_fill_super(sb, fc);
 289 }
 290
 291 static int jffs2_get_tree(struct fs_context *fc)
 292 {
 293         return get_tree_mtd(fc, jffs2_fill_super);
 294 }
 295
 296 static void jffs2_free_fc(struct fs_context *fc)
 297 {
 298         kfree(fc->s_fs_info);
 299 }
 300
 301 static const struct fs_context_operations jffs2_context_ops = {
 302         .free           = jffs2_free_fc,
 303         .parse_param    = jffs2_parse_param,
 304         .get_tree       = jffs2_get_tree,
 305         .reconfigure    = jffs2_reconfigure,
 306 };
 307
 308 static int jffs2_init_fs_context(struct fs_context *fc)
 309 {
 310         struct jffs2_sb_info *ctx;
 311
 312         ctx = kzalloc(sizeof(struct jffs2_sb_info), GFP_KERNEL);
 313         if (!ctx)
 314                 return -ENOMEM;
 315
 316         fc->s_fs_info = ctx;
 317         fc->ops = &jffs2_context_ops;
 318         return 0;
 319 }
 320
 321 static void jffs2_put_super (struct super_block *sb)
 322 {
 323         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 324
 325         jffs2_dbg(2, "%s()\n", __func__);
 326
 327         mutex_lock(&c->alloc_sem);
 328         jffs2_flush_wbuf_pad(c);
 329         mutex_unlock(&c->alloc_sem);
 330
 331         jffs2_sum_exit(c);
 332
 333         jffs2_free_ino_caches(c);
 334         jffs2_free_raw_node_refs(c);
 335         kvfree(c->blocks);
 336         jffs2_flash_cleanup(c);
 337         kfree(c->inocache_list);
 338         jffs2_clear_xattr_subsystem(c);
 339         mtd_sync(c->mtd);
 340         jffs2_dbg(1, "%s(): returning\n", __func__);
 341 }
 342
 343 static void jffs2_kill_sb(struct super_block *sb)
 344 {
 345         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 346         if (c && !sb_rdonly(sb))
 347                 jffs2_stop_garbage_collect_thread(c);
 348         kill_mtd_super(sb);
 349         kfree(c);
 350 }
 351
 352 static struct file_system_type jffs2_fs_type = {
 353         .owner =        THIS_MODULE,
 354         .name =         "jffs2",
 355         .init_fs_context = jffs2_init_fs_context,
 356         .parameters =   jffs2_fs_parameters,
 357         .kill_sb =      jffs2_kill_sb,
 358 };
 359 MODULE_ALIAS_FS("jffs2");
 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         pr_info("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|SLAB_ACCOUNT),
 390                                              jffs2_i_init_once);
 391         if (!jffs2_inode_cachep) {
 392                 pr_err("error: Failed to initialise inode cache\n");
 393                 return -ENOMEM;
 394         }
 395         ret = jffs2_compressors_init();
 396         if (ret) {
 397                 pr_err("error: Failed to initialise compressors\n");
 398                 goto out;
 399         }
 400         ret = jffs2_create_slab_caches();
 401         if (ret) {
 402                 pr_err("error: Failed to initialise slab caches\n");
 403                 goto out_compressors;
 404         }
 405         ret = register_filesystem(&jffs2_fs_type);
 406         if (ret) {
 407                 pr_err("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
 427         /*
 428          * Make sure all delayed rcu free inodes are flushed before we
 429          * destroy cache.
 430          */
 431         rcu_barrier();
 432         kmem_cache_destroy(jffs2_inode_cachep);
 433 }
 434
 435 module_init(init_jffs2_fs);
 436 module_exit(exit_jffs2_fs);
 437
 438 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 439 MODULE_AUTHOR("Red Hat, Inc.");
 440 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 441                        // the sake of this tag. It's Free Software.