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