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