linux/fs/jffs2/super.c
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   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/smp_lock.h>
  16#include <linux/init.h>
  17#include <linux/list.h>
  18#include <linux/fs.h>
  19#include <linux/err.h>
  20#include <linux/mount.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/exportfs.h>
  27#include "compr.h"
  28#include "nodelist.h"
  29
  30static void jffs2_put_super(struct super_block *);
  31
  32static struct kmem_cache *jffs2_inode_cachep;
  33
  34static struct inode *jffs2_alloc_inode(struct super_block *sb)
  35{
  36        struct jffs2_inode_info *f;
  37
  38        f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
  39        if (!f)
  40                return NULL;
  41        return &f->vfs_inode;
  42}
  43
  44static void jffs2_destroy_inode(struct inode *inode)
  45{
  46        kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  47}
  48
  49static void jffs2_i_init_once(void *foo)
  50{
  51        struct jffs2_inode_info *f = foo;
  52
  53        mutex_init(&f->sem);
  54        inode_init_once(&f->vfs_inode);
  55}
  56
  57static void jffs2_write_super(struct super_block *sb)
  58{
  59        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  60
  61        lock_super(sb);
  62        sb->s_dirt = 0;
  63
  64        if (!(sb->s_flags & MS_RDONLY)) {
  65                D1(printk(KERN_DEBUG "jffs2_write_super()\n"));
  66                jffs2_garbage_collect_trigger(c);
  67                jffs2_erase_pending_blocks(c, 0);
  68                jffs2_flush_wbuf_gc(c, 0);
  69        }
  70
  71        unlock_super(sb);
  72}
  73
  74static int jffs2_sync_fs(struct super_block *sb, int wait)
  75{
  76        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  77
  78        jffs2_write_super(sb);
  79
  80        mutex_lock(&c->alloc_sem);
  81        jffs2_flush_wbuf_pad(c);
  82        mutex_unlock(&c->alloc_sem);
  83        return 0;
  84}
  85
  86static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
  87                                         uint32_t generation)
  88{
  89        /* We don't care about i_generation. We'll destroy the flash
  90           before we start re-using inode numbers anyway. And even
  91           if that wasn't true, we'd have other problems...*/
  92        return jffs2_iget(sb, ino);
  93}
  94
  95static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
  96                                         int fh_len, int fh_type)
  97{
  98        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
  99                                    jffs2_nfs_get_inode);
 100}
 101
 102static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 103                                         int fh_len, int fh_type)
 104{
 105        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 106                                    jffs2_nfs_get_inode);
 107}
 108
 109static struct dentry *jffs2_get_parent(struct dentry *child)
 110{
 111        struct jffs2_inode_info *f;
 112        uint32_t pino;
 113
 114        BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 115
 116        f = JFFS2_INODE_INFO(child->d_inode);
 117
 118        pino = f->inocache->pino_nlink;
 119
 120        JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 121                    f->inocache->ino, pino);
 122
 123        return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 124}
 125
 126static const struct export_operations jffs2_export_ops = {
 127        .get_parent = jffs2_get_parent,
 128        .fh_to_dentry = jffs2_fh_to_dentry,
 129        .fh_to_parent = jffs2_fh_to_parent,
 130};
 131
 132static const struct super_operations jffs2_super_operations =
 133{
 134        .alloc_inode =  jffs2_alloc_inode,
 135        .destroy_inode =jffs2_destroy_inode,
 136        .put_super =    jffs2_put_super,
 137        .write_super =  jffs2_write_super,
 138        .statfs =       jffs2_statfs,
 139        .remount_fs =   jffs2_remount_fs,
 140        .clear_inode =  jffs2_clear_inode,
 141        .dirty_inode =  jffs2_dirty_inode,
 142        .sync_fs =      jffs2_sync_fs,
 143};
 144
 145/*
 146 * fill in the superblock
 147 */
 148static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 149{
 150        struct jffs2_sb_info *c;
 151
 152        D1(printk(KERN_DEBUG "jffs2_get_sb_mtd():"
 153                  " New superblock for device %d (\"%s\")\n",
 154                  sb->s_mtd->index, sb->s_mtd->name));
 155
 156        c = kzalloc(sizeof(*c), GFP_KERNEL);
 157        if (!c)
 158                return -ENOMEM;
 159
 160        c->mtd = sb->s_mtd;
 161        c->os_priv = sb;
 162        sb->s_fs_info = c;
 163
 164        /* Initialize JFFS2 superblock locks, the further initialization will
 165         * be done later */
 166        mutex_init(&c->alloc_sem);
 167        mutex_init(&c->erase_free_sem);
 168        init_waitqueue_head(&c->erase_wait);
 169        init_waitqueue_head(&c->inocache_wq);
 170        spin_lock_init(&c->erase_completion_lock);
 171        spin_lock_init(&c->inocache_lock);
 172
 173        sb->s_op = &jffs2_super_operations;
 174        sb->s_export_op = &jffs2_export_ops;
 175        sb->s_flags = sb->s_flags | MS_NOATIME;
 176        sb->s_xattr = jffs2_xattr_handlers;
 177#ifdef CONFIG_JFFS2_FS_POSIX_ACL
 178        sb->s_flags |= MS_POSIXACL;
 179#endif
 180        return jffs2_do_fill_super(sb, data, silent);
 181}
 182
 183static int jffs2_get_sb(struct file_system_type *fs_type,
 184                        int flags, const char *dev_name,
 185                        void *data, struct vfsmount *mnt)
 186{
 187        return get_sb_mtd(fs_type, flags, dev_name, data, jffs2_fill_super,
 188                          mnt);
 189}
 190
 191static void jffs2_put_super (struct super_block *sb)
 192{
 193        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 194
 195        D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 196
 197        lock_kernel();
 198
 199        if (sb->s_dirt)
 200                jffs2_write_super(sb);
 201
 202        mutex_lock(&c->alloc_sem);
 203        jffs2_flush_wbuf_pad(c);
 204        mutex_unlock(&c->alloc_sem);
 205
 206        jffs2_sum_exit(c);
 207
 208        jffs2_free_ino_caches(c);
 209        jffs2_free_raw_node_refs(c);
 210        if (jffs2_blocks_use_vmalloc(c))
 211                vfree(c->blocks);
 212        else
 213                kfree(c->blocks);
 214        jffs2_flash_cleanup(c);
 215        kfree(c->inocache_list);
 216        jffs2_clear_xattr_subsystem(c);
 217        if (c->mtd->sync)
 218                c->mtd->sync(c->mtd);
 219
 220        unlock_kernel();
 221
 222        D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 223}
 224
 225static void jffs2_kill_sb(struct super_block *sb)
 226{
 227        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 228        if (!(sb->s_flags & MS_RDONLY))
 229                jffs2_stop_garbage_collect_thread(c);
 230        kill_mtd_super(sb);
 231        kfree(c);
 232}
 233
 234static struct file_system_type jffs2_fs_type = {
 235        .owner =        THIS_MODULE,
 236        .name =         "jffs2",
 237        .get_sb =       jffs2_get_sb,
 238        .kill_sb =      jffs2_kill_sb,
 239};
 240
 241static int __init init_jffs2_fs(void)
 242{
 243        int ret;
 244
 245        /* Paranoia checks for on-medium structures. If we ask GCC
 246           to pack them with __attribute__((packed)) then it _also_
 247           assumes that they're not aligned -- so it emits crappy
 248           code on some architectures. Ideally we want an attribute
 249           which means just 'no padding', without the alignment
 250           thing. But GCC doesn't have that -- we have to just
 251           hope the structs are the right sizes, instead. */
 252        BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 253        BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 254        BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 255        BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 256
 257        printk(KERN_INFO "JFFS2 version 2.2."
 258#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 259               " (NAND)"
 260#endif
 261#ifdef CONFIG_JFFS2_SUMMARY
 262               " (SUMMARY) "
 263#endif
 264               " © 2001-2006 Red Hat, Inc.\n");
 265
 266        jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 267                                             sizeof(struct jffs2_inode_info),
 268                                             0, (SLAB_RECLAIM_ACCOUNT|
 269                                                SLAB_MEM_SPREAD),
 270                                             jffs2_i_init_once);
 271        if (!jffs2_inode_cachep) {
 272                printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 273                return -ENOMEM;
 274        }
 275        ret = jffs2_compressors_init();
 276        if (ret) {
 277                printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
 278                goto out;
 279        }
 280        ret = jffs2_create_slab_caches();
 281        if (ret) {
 282                printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 283                goto out_compressors;
 284        }
 285        ret = register_filesystem(&jffs2_fs_type);
 286        if (ret) {
 287                printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
 288                goto out_slab;
 289        }
 290        return 0;
 291
 292 out_slab:
 293        jffs2_destroy_slab_caches();
 294 out_compressors:
 295        jffs2_compressors_exit();
 296 out:
 297        kmem_cache_destroy(jffs2_inode_cachep);
 298        return ret;
 299}
 300
 301static void __exit exit_jffs2_fs(void)
 302{
 303        unregister_filesystem(&jffs2_fs_type);
 304        jffs2_destroy_slab_caches();
 305        jffs2_compressors_exit();
 306        kmem_cache_destroy(jffs2_inode_cachep);
 307}
 308
 309module_init(init_jffs2_fs);
 310module_exit(exit_jffs2_fs);
 311
 312MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 313MODULE_AUTHOR("Red Hat, Inc.");
 314MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 315                       // the sake of this tag. It's Free Software.
 316