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/mtd.h>
  23 #include <linux/ctype.h>
  24 #include <linux/namei.h>
  25 #include "compr.h"
  26 #include "nodelist.h"
  27
  28 static void jffs2_put_super(struct super_block *);
  29
  30 static struct kmem_cache *jffs2_inode_cachep;
  31
  32 static struct inode *jffs2_alloc_inode(struct super_block *sb)
  33 {
  34         struct jffs2_inode_info *ei;
  35         ei = (struct jffs2_inode_info *)kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
  36         if (!ei)
  37                 return NULL;
  38         return &ei->vfs_inode;
  39 }
  40
  41 static void jffs2_destroy_inode(struct inode *inode)
  42 {
  43         kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  44 }
  45
  46 static void jffs2_i_init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
  47 {
  48         struct jffs2_inode_info *ei = (struct jffs2_inode_info *) foo;
  49
  50         if (flags & SLAB_CTOR_CONSTRUCTOR) {
  51                 init_MUTEX(&ei->sem);
  52                 inode_init_once(&ei->vfs_inode);
  53         }
  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         down(&c->alloc_sem);
  61         jffs2_flush_wbuf_pad(c);
  62         up(&c->alloc_sem);
  63         return 0;
  64 }
  65
  66 static const struct super_operations jffs2_super_operations =
  67 {
  68         .alloc_inode =  jffs2_alloc_inode,
  69         .destroy_inode =jffs2_destroy_inode,
  70         .read_inode =   jffs2_read_inode,
  71         .put_super =    jffs2_put_super,
  72         .write_super =  jffs2_write_super,
  73         .statfs =       jffs2_statfs,
  74         .remount_fs =   jffs2_remount_fs,
  75         .clear_inode =  jffs2_clear_inode,
  76         .dirty_inode =  jffs2_dirty_inode,
  77         .sync_fs =      jffs2_sync_fs,
  78 };
  79
  80 static int jffs2_sb_compare(struct super_block *sb, void *data)
  81 {
  82         struct jffs2_sb_info *p = data;
  83         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  84
  85         /* The superblocks are considered to be equivalent if the underlying MTD
  86            device is the same one */
  87         if (c->mtd == p->mtd) {
  88                 D1(printk(KERN_DEBUG "jffs2_sb_compare: match on device %d (\"%s\")\n", p->mtd->index, p->mtd->name));
  89                 return 1;
  90         } else {
  91                 D1(printk(KERN_DEBUG "jffs2_sb_compare: No match, device %d (\"%s\"), device %d (\"%s\")\n",
  92                           c->mtd->index, c->mtd->name, p->mtd->index, p->mtd->name));
  93                 return 0;
  94         }
  95 }
  96
  97 static int jffs2_sb_set(struct super_block *sb, void *data)
  98 {
  99         struct jffs2_sb_info *p = data;
 100
 101         /* For persistence of NFS exports etc. we use the same s_dev
 102            each time we mount the device, don't just use an anonymous
 103            device */
 104         sb->s_fs_info = p;
 105         p->os_priv = sb;
 106         sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, p->mtd->index);
 107
 108         return 0;
 109 }
 110
 111 static int jffs2_get_sb_mtd(struct file_system_type *fs_type,
 112                             int flags, const char *dev_name,
 113                             void *data, struct mtd_info *mtd,
 114                             struct vfsmount *mnt)
 115 {
 116         struct super_block *sb;
 117         struct jffs2_sb_info *c;
 118         int ret;
 119
 120         c = kzalloc(sizeof(*c), GFP_KERNEL);
 121         if (!c)
 122                 return -ENOMEM;
 123         c->mtd = mtd;
 124
 125         sb = sget(fs_type, jffs2_sb_compare, jffs2_sb_set, c);
 126
 127         if (IS_ERR(sb))
 128                 goto out_error;
 129
 130         if (sb->s_root) {
 131                 /* New mountpoint for JFFS2 which is already mounted */
 132                 D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): Device %d (\"%s\") is already mounted\n",
 133                           mtd->index, mtd->name));
 134                 ret = simple_set_mnt(mnt, sb);
 135                 goto out_put;
 136         }
 137
 138         D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d (\"%s\")\n",
 139                   mtd->index, mtd->name));
 140
 141         /* Initialize JFFS2 superblock locks, the further initialization will be
 142          * done later */
 143         init_MUTEX(&c->alloc_sem);
 144         init_MUTEX(&c->erase_free_sem);
 145         init_waitqueue_head(&c->erase_wait);
 146         init_waitqueue_head(&c->inocache_wq);
 147         spin_lock_init(&c->erase_completion_lock);
 148         spin_lock_init(&c->inocache_lock);
 149
 150         sb->s_op = &jffs2_super_operations;
 151         sb->s_flags = flags | MS_NOATIME;
 152         sb->s_xattr = jffs2_xattr_handlers;
 153 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 154         sb->s_flags |= MS_POSIXACL;
 155 #endif
 156         ret = jffs2_do_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
 157
 158         if (ret) {
 159                 /* Failure case... */
 160                 up_write(&sb->s_umount);
 161                 deactivate_super(sb);
 162                 return ret;
 163         }
 164
 165         sb->s_flags |= MS_ACTIVE;
 166         return simple_set_mnt(mnt, sb);
 167
 168 out_error:
 169         ret = PTR_ERR(sb);
 170  out_put:
 171         kfree(c);
 172         put_mtd_device(mtd);
 173
 174         return ret;
 175 }
 176
 177 static int jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
 178                               int flags, const char *dev_name,
 179                               void *data, int mtdnr,
 180                               struct vfsmount *mnt)
 181 {
 182         struct mtd_info *mtd;
 183
 184         mtd = get_mtd_device(NULL, mtdnr);
 185         if (IS_ERR(mtd)) {
 186                 D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
 187                 return PTR_ERR(mtd);
 188         }
 189
 190         return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd, mnt);
 191 }
 192
 193 static int jffs2_get_sb(struct file_system_type *fs_type,
 194                         int flags, const char *dev_name,
 195                         void *data, struct vfsmount *mnt)
 196 {
 197         int err;
 198         struct nameidata nd;
 199         int mtdnr;
 200
 201         if (!dev_name)
 202                 return -EINVAL;
 203
 204         D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
 205
 206         /* The preferred way of mounting in future; especially when
 207            CONFIG_BLK_DEV is implemented - we specify the underlying
 208            MTD device by number or by name, so that we don't require
 209            block device support to be present in the kernel. */
 210
 211         /* FIXME: How to do the root fs this way? */
 212
 213         if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
 214                 /* Probably mounting without the blkdev crap */
 215                 if (dev_name[3] == ':') {
 216                         struct mtd_info *mtd;
 217
 218                         /* Mount by MTD device name */
 219                         D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name \"%s\"\n", dev_name+4));
 220                         for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
 221                                 mtd = get_mtd_device(NULL, mtdnr);
 222                                 if (!IS_ERR(mtd)) {
 223                                         if (!strcmp(mtd->name, dev_name+4))
 224                                                 return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd, mnt);
 225                                         put_mtd_device(mtd);
 226                                 }
 227                         }
 228                         printk(KERN_NOTICE "jffs2_get_sb(): MTD device with name \"%s\" not found.\n", dev_name+4);
 229                 } else if (isdigit(dev_name[3])) {
 230                         /* Mount by MTD device number name */
 231                         char *endptr;
 232
 233                         mtdnr = simple_strtoul(dev_name+3, &endptr, 0);
 234                         if (!*endptr) {
 235                                 /* It was a valid number */
 236                                 D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, mtdnr %d\n", mtdnr));
 237                                 return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr, mnt);
 238                         }
 239                 }
 240         }
 241
 242         /* Try the old way - the hack where we allowed users to mount
 243            /dev/mtdblock$(n) but didn't actually _use_ the blkdev */
 244
 245         err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
 246
 247         D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode %p\n",
 248                   err, nd.dentry->d_inode));
 249
 250         if (err)
 251                 return err;
 252
 253         err = -EINVAL;
 254
 255         if (!S_ISBLK(nd.dentry->d_inode->i_mode))
 256                 goto out;
 257
 258         if (nd.mnt->mnt_flags & MNT_NODEV) {
 259                 err = -EACCES;
 260                 goto out;
 261         }
 262
 263         if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
 264                 if (!(flags & MS_SILENT))
 265                         printk(KERN_NOTICE "Attempt to mount non-MTD device \"%s\" as JFFS2\n",
 266                                dev_name);
 267                 goto out;
 268         }
 269
 270         mtdnr = iminor(nd.dentry->d_inode);
 271         path_release(&nd);
 272
 273         return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr, mnt);
 274
 275 out:
 276         path_release(&nd);
 277         return err;
 278 }
 279
 280 static void jffs2_put_super (struct super_block *sb)
 281 {
 282         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 283
 284         D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 285
 286         down(&c->alloc_sem);
 287         jffs2_flush_wbuf_pad(c);
 288         up(&c->alloc_sem);
 289
 290         jffs2_sum_exit(c);
 291
 292         jffs2_free_ino_caches(c);
 293         jffs2_free_raw_node_refs(c);
 294         if (jffs2_blocks_use_vmalloc(c))
 295                 vfree(c->blocks);
 296         else
 297                 kfree(c->blocks);
 298         jffs2_flash_cleanup(c);
 299         kfree(c->inocache_list);
 300         jffs2_clear_xattr_subsystem(c);
 301         if (c->mtd->sync)
 302                 c->mtd->sync(c->mtd);
 303
 304         D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 305 }
 306
 307 static void jffs2_kill_sb(struct super_block *sb)
 308 {
 309         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 310         if (!(sb->s_flags & MS_RDONLY))
 311                 jffs2_stop_garbage_collect_thread(c);
 312         generic_shutdown_super(sb);
 313         put_mtd_device(c->mtd);
 314         kfree(c);
 315 }
 316
 317 static struct file_system_type jffs2_fs_type = {
 318         .owner =        THIS_MODULE,
 319         .name =         "jffs2",
 320         .get_sb =       jffs2_get_sb,
 321         .kill_sb =      jffs2_kill_sb,
 322 };
 323
 324 static int __init init_jffs2_fs(void)
 325 {
 326         int ret;
 327
 328         /* Paranoia checks for on-medium structures. If we ask GCC
 329            to pack them with __attribute__((packed)) then it _also_
 330            assumes that they're not aligned -- so it emits crappy
 331            code on some architectures. Ideally we want an attribute
 332            which means just 'no padding', without the alignment
 333            thing. But GCC doesn't have that -- we have to just
 334            hope the structs are the right sizes, instead. */
 335         BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 336         BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 337         BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 338         BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 339
 340         printk(KERN_INFO "JFFS2 version 2.2."
 341 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 342                " (NAND)"
 343 #endif
 344 #ifdef CONFIG_JFFS2_SUMMARY
 345                " (SUMMARY) "
 346 #endif
 347                " © 2001-2006 Red Hat, Inc.\n");
 348
 349         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 350                                              sizeof(struct jffs2_inode_info),
 351                                              0, (SLAB_RECLAIM_ACCOUNT|
 352                                                 SLAB_MEM_SPREAD),
 353                                              jffs2_i_init_once, NULL);
 354         if (!jffs2_inode_cachep) {
 355                 printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 356                 return -ENOMEM;
 357         }
 358         ret = jffs2_compressors_init();
 359         if (ret) {
 360                 printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
 361                 goto out;
 362         }
 363         ret = jffs2_create_slab_caches();
 364         if (ret) {
 365                 printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 366                 goto out_compressors;
 367         }
 368         ret = register_filesystem(&jffs2_fs_type);
 369         if (ret) {
 370                 printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
 371                 goto out_slab;
 372         }
 373         return 0;
 374
 375  out_slab:
 376         jffs2_destroy_slab_caches();
 377  out_compressors:
 378         jffs2_compressors_exit();
 379  out:
 380         kmem_cache_destroy(jffs2_inode_cachep);
 381         return ret;
 382 }
 383
 384 static void __exit exit_jffs2_fs(void)
 385 {
 386         unregister_filesystem(&jffs2_fs_type);
 387         jffs2_destroy_slab_caches();
 388         jffs2_compressors_exit();
 389         kmem_cache_destroy(jffs2_inode_cachep);
 390 }
 391
 392 module_init(init_jffs2_fs);
 393 module_exit(exit_jffs2_fs);
 394
 395 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 396 MODULE_AUTHOR("Red Hat, Inc.");
 397 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 398                        // the sake of this tag. It's Free Software.