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