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_i_callback(struct rcu_head *head)
  44 {
  45         struct inode *inode = container_of(head, struct inode, i_rcu);
  46         INIT_LIST_HEAD(&inode->i_dentry);
  47         kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  48 }
  49
  50 static void jffs2_destroy_inode(struct inode *inode)
  51 {
  52         call_rcu(&inode->i_rcu, jffs2_i_callback);
  53 }
  54
  55 static void jffs2_i_init_once(void *foo)
  56 {
  57         struct jffs2_inode_info *f = foo;
  58
  59         mutex_init(&f->sem);
  60         inode_init_once(&f->vfs_inode);
  61 }
  62
  63 static void jffs2_write_super(struct super_block *sb)
  64 {
  65         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  66
  67         lock_super(sb);
  68         sb->s_dirt = 0;
  69
  70         if (!(sb->s_flags & MS_RDONLY)) {
  71                 D1(printk(KERN_DEBUG "jffs2_write_super()\n"));
  72                 jffs2_flush_wbuf_gc(c, 0);
  73         }
  74
  75         unlock_super(sb);
  76 }
  77
  78 static int jffs2_sync_fs(struct super_block *sb, int wait)
  79 {
  80         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  81
  82         jffs2_write_super(sb);
  83
  84         mutex_lock(&c->alloc_sem);
  85         jffs2_flush_wbuf_pad(c);
  86         mutex_unlock(&c->alloc_sem);
  87         return 0;
  88 }
  89
  90 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
  91                                          uint32_t generation)
  92 {
  93         /* We don't care about i_generation. We'll destroy the flash
  94            before we start re-using inode numbers anyway. And even
  95            if that wasn't true, we'd have other problems...*/
  96         return jffs2_iget(sb, ino);
  97 }
  98
  99 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 100                                          int fh_len, int fh_type)
 101 {
 102         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 103                                     jffs2_nfs_get_inode);
 104 }
 105
 106 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 107                                          int fh_len, int fh_type)
 108 {
 109         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 110                                     jffs2_nfs_get_inode);
 111 }
 112
 113 static struct dentry *jffs2_get_parent(struct dentry *child)
 114 {
 115         struct jffs2_inode_info *f;
 116         uint32_t pino;
 117
 118         BUG_ON(!S_ISDIR(child->d_inode->i_mode));
 119
 120         f = JFFS2_INODE_INFO(child->d_inode);
 121
 122         pino = f->inocache->pino_nlink;
 123
 124         JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 125                     f->inocache->ino, pino);
 126
 127         return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
 128 }
 129
 130 static const struct export_operations jffs2_export_ops = {
 131         .get_parent = jffs2_get_parent,
 132         .fh_to_dentry = jffs2_fh_to_dentry,
 133         .fh_to_parent = jffs2_fh_to_parent,
 134 };
 135
 136 static const struct super_operations jffs2_super_operations =
 137 {
 138         .alloc_inode =  jffs2_alloc_inode,
 139         .destroy_inode =jffs2_destroy_inode,
 140         .put_super =    jffs2_put_super,
 141         .write_super =  jffs2_write_super,
 142         .statfs =       jffs2_statfs,
 143         .remount_fs =   jffs2_remount_fs,
 144         .evict_inode =  jffs2_evict_inode,
 145         .dirty_inode =  jffs2_dirty_inode,
 146         .sync_fs =      jffs2_sync_fs,
 147 };
 148
 149 /*
 150  * fill in the superblock
 151  */
 152 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 153 {
 154         struct jffs2_sb_info *c;
 155         int ret;
 156
 157         D1(printk(KERN_DEBUG "jffs2_get_sb_mtd():"
 158                   " New superblock for device %d (\"%s\")\n",
 159                   sb->s_mtd->index, sb->s_mtd->name));
 160
 161         c = kzalloc(sizeof(*c), GFP_KERNEL);
 162         if (!c)
 163                 return -ENOMEM;
 164
 165         c->mtd = sb->s_mtd;
 166         c->os_priv = sb;
 167         sb->s_fs_info = c;
 168
 169         /* Initialize JFFS2 superblock locks, the further initialization will
 170          * be done later */
 171         mutex_init(&c->alloc_sem);
 172         mutex_init(&c->erase_free_sem);
 173         init_waitqueue_head(&c->erase_wait);
 174         init_waitqueue_head(&c->inocache_wq);
 175         spin_lock_init(&c->erase_completion_lock);
 176         spin_lock_init(&c->inocache_lock);
 177
 178         sb->s_op = &jffs2_super_operations;
 179         sb->s_export_op = &jffs2_export_ops;
 180         sb->s_flags = sb->s_flags | MS_NOATIME;
 181         sb->s_xattr = jffs2_xattr_handlers;
 182 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 183         sb->s_flags |= MS_POSIXACL;
 184 #endif
 185         ret = jffs2_do_fill_super(sb, data, silent);
 186         return ret;
 187 }
 188
 189 static struct dentry *jffs2_mount(struct file_system_type *fs_type,
 190                         int flags, const char *dev_name,
 191                         void *data)
 192 {
 193         return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);
 194 }
 195
 196 static void jffs2_put_super (struct super_block *sb)
 197 {
 198         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 199
 200         D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 201
 202         if (sb->s_dirt)
 203                 jffs2_write_super(sb);
 204
 205         mutex_lock(&c->alloc_sem);
 206         jffs2_flush_wbuf_pad(c);
 207         mutex_unlock(&c->alloc_sem);
 208
 209         jffs2_sum_exit(c);
 210
 211         jffs2_free_ino_caches(c);
 212         jffs2_free_raw_node_refs(c);
 213         if (jffs2_blocks_use_vmalloc(c))
 214                 vfree(c->blocks);
 215         else
 216                 kfree(c->blocks);
 217         jffs2_flash_cleanup(c);
 218         kfree(c->inocache_list);
 219         jffs2_clear_xattr_subsystem(c);
 220         if (c->mtd->sync)
 221                 c->mtd->sync(c->mtd);
 222
 223         D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 224 }
 225
 226 static void jffs2_kill_sb(struct super_block *sb)
 227 {
 228         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 229         if (!(sb->s_flags & MS_RDONLY))
 230                 jffs2_stop_garbage_collect_thread(c);
 231         kill_mtd_super(sb);
 232         kfree(c);
 233 }
 234
 235 static struct file_system_type jffs2_fs_type = {
 236         .owner =        THIS_MODULE,
 237         .name =         "jffs2",
 238         .mount =        jffs2_mount,
 239         .kill_sb =      jffs2_kill_sb,
 240 };
 241
 242 static int __init init_jffs2_fs(void)
 243 {
 244         int ret;
 245
 246         /* Paranoia checks for on-medium structures. If we ask GCC
 247            to pack them with __attribute__((packed)) then it _also_
 248            assumes that they're not aligned -- so it emits crappy
 249            code on some architectures. Ideally we want an attribute
 250            which means just 'no padding', without the alignment
 251            thing. But GCC doesn't have that -- we have to just
 252            hope the structs are the right sizes, instead. */
 253         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 254         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 255         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 256         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 257
 258         printk(KERN_INFO "JFFS2 version 2.2."
 259 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 260                " (NAND)"
 261 #endif
 262 #ifdef CONFIG_JFFS2_SUMMARY
 263                " (SUMMARY) "
 264 #endif
 265                " © 2001-2006 Red Hat, Inc.\n");
 266
 267         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 268                                              sizeof(struct jffs2_inode_info),
 269                                              0, (SLAB_RECLAIM_ACCOUNT|
 270                                                 SLAB_MEM_SPREAD),
 271                                              jffs2_i_init_once);
 272         if (!jffs2_inode_cachep) {
 273                 printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 274                 return -ENOMEM;
 275         }
 276         ret = jffs2_compressors_init();
 277         if (ret) {
 278                 printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
 279                 goto out;
 280         }
 281         ret = jffs2_create_slab_caches();
 282         if (ret) {
 283                 printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 284                 goto out_compressors;
 285         }
 286         ret = register_filesystem(&jffs2_fs_type);
 287         if (ret) {
 288                 printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
 289                 goto out_slab;
 290         }
 291         return 0;
 292
 293  out_slab:
 294         jffs2_destroy_slab_caches();
 295  out_compressors:
 296         jffs2_compressors_exit();
 297  out:
 298         kmem_cache_destroy(jffs2_inode_cachep);
 299         return ret;
 300 }
 301
 302 static void __exit exit_jffs2_fs(void)
 303 {
 304         unregister_filesystem(&jffs2_fs_type);
 305         jffs2_destroy_slab_caches();
 306         jffs2_compressors_exit();
 307         kmem_cache_destroy(jffs2_inode_cachep);
 308 }
 309
 310 module_init(init_jffs2_fs);
 311 module_exit(exit_jffs2_fs);
 312
 313 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 314 MODULE_AUTHOR("Red Hat, Inc.");
 315 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 316                        // the sake of this tag. It's Free Software.