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