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/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
  30 static void jffs2_put_super(struct super_block *);
  31
  32 static struct kmem_cache *jffs2_inode_cachep;
  33
  34 static 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
  44 static void jffs2_destroy_inode(struct inode *inode)
  45 {
  46         kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  47 }
  48
  49 static 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
  57 static 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
  74 static 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
  86 static 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
  95 static 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
 102 static 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
 109 static 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
 126 static 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
 132 static 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  */
 148 static 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
 183 static 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
 191 static 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
 225 static 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
 234 static 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
 241 static 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
 301 static 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
 309 module_init(init_jffs2_fs);
 310 module_exit(exit_jffs2_fs);
 311
 312 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 313 MODULE_AUTHOR("Red Hat, Inc.");
 314 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 315                        // the sake of this tag. It's Free Software.