fs/jffs2/super.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 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  * $Id: super.c,v 1.110 2005/11/07 11:14:42 gleixner Exp $
  11  *
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/init.h>
  19 #include <linux/list.h>
  20 #include <linux/fs.h>
  21 #include <linux/mount.h>
  22 #include <linux/jffs2.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/mtd/mtd.h>
  25 #include <linux/ctype.h>
  26 #include <linux/namei.h>
  27 #include "compr.h"
  28 #include "nodelist.h"
  29
  30 static void jffs2_put_super(struct super_block *);
  31
  32 static kmem_cache_t *jffs2_inode_cachep;
  33
  34 static struct inode *jffs2_alloc_inode(struct super_block *sb)
  35 {
  36         struct jffs2_inode_info *ei;
  37         ei = (struct jffs2_inode_info *)kmem_cache_alloc(jffs2_inode_cachep, SLAB_KERNEL);
  38         if (!ei)
  39                 return NULL;
  40         return &ei->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, kmem_cache_t * cachep, unsigned long flags)
  49 {
  50         struct jffs2_inode_info *ei = (struct jffs2_inode_info *) foo;
  51
  52         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
  53             SLAB_CTOR_CONSTRUCTOR) {
  54                 init_MUTEX(&ei->sem);
  55                 inode_init_once(&ei->vfs_inode);
  56         }
  57 }
  58
  59 static int jffs2_sync_fs(struct super_block *sb, int wait)
  60 {
  61         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  62
  63         down(&c->alloc_sem);
  64         jffs2_flush_wbuf_pad(c);
  65         up(&c->alloc_sem);
  66         return 0;
  67 }
  68
  69 static struct super_operations jffs2_super_operations =
  70 {
  71         .alloc_inode =  jffs2_alloc_inode,
  72         .destroy_inode =jffs2_destroy_inode,
  73         .read_inode =   jffs2_read_inode,
  74         .put_super =    jffs2_put_super,
  75         .write_super =  jffs2_write_super,
  76         .statfs =       jffs2_statfs,
  77         .remount_fs =   jffs2_remount_fs,
  78         .clear_inode =  jffs2_clear_inode,
  79         .dirty_inode =  jffs2_dirty_inode,
  80         .sync_fs =      jffs2_sync_fs,
  81 };
  82
  83 static int jffs2_sb_compare(struct super_block *sb, void *data)
  84 {
  85         struct jffs2_sb_info *p = data;
  86         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  87
  88         /* The superblocks are considered to be equivalent if the underlying MTD
  89            device is the same one */
  90         if (c->mtd == p->mtd) {
  91                 D1(printk(KERN_DEBUG "jffs2_sb_compare: match on device %d (\"%s\")\n", p->mtd->index, p->mtd->name));
  92                 return 1;
  93         } else {
  94                 D1(printk(KERN_DEBUG "jffs2_sb_compare: No match, device %d (\"%s\"), device %d (\"%s\")\n",
  95                           c->mtd->index, c->mtd->name, p->mtd->index, p->mtd->name));
  96                 return 0;
  97         }
  98 }
  99
 100 static int jffs2_sb_set(struct super_block *sb, void *data)
 101 {
 102         struct jffs2_sb_info *p = data;
 103
 104         /* For persistence of NFS exports etc. we use the same s_dev
 105            each time we mount the device, don't just use an anonymous
 106            device */
 107         sb->s_fs_info = p;
 108         p->os_priv = sb;
 109         sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, p->mtd->index);
 110
 111         return 0;
 112 }
 113
 114 static struct super_block *jffs2_get_sb_mtd(struct file_system_type *fs_type,
 115                                               int flags, const char *dev_name,
 116                                               void *data, struct mtd_info *mtd)
 117 {
 118         struct super_block *sb;
 119         struct jffs2_sb_info *c;
 120         int ret;
 121
 122         c = kmalloc(sizeof(*c), GFP_KERNEL);
 123         if (!c)
 124                 return ERR_PTR(-ENOMEM);
 125         memset(c, 0, sizeof(*c));
 126         c->mtd = mtd;
 127
 128         sb = sget(fs_type, jffs2_sb_compare, jffs2_sb_set, c);
 129
 130         if (IS_ERR(sb))
 131                 goto out_put;
 132
 133         if (sb->s_root) {
 134                 /* New mountpoint for JFFS2 which is already mounted */
 135                 D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): Device %d (\"%s\") is already mounted\n",
 136                           mtd->index, mtd->name));
 137                 goto out_put;
 138         }
 139
 140         D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d (\"%s\")\n",
 141                   mtd->index, mtd->name));
 142
 143         /* Initialize JFFS2 superblock locks, the further initialization will be
 144          * done later */
 145         init_MUTEX(&c->alloc_sem);
 146         init_MUTEX(&c->erase_free_sem);
 147         init_waitqueue_head(&c->erase_wait);
 148         init_waitqueue_head(&c->inocache_wq);
 149         spin_lock_init(&c->erase_completion_lock);
 150         spin_lock_init(&c->inocache_lock);
 151
 152         sb->s_op = &jffs2_super_operations;
 153         sb->s_flags = flags | MS_NOATIME;
 154         sb->s_xattr = jffs2_xattr_handlers;
 155 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 156         sb->s_flags |= MS_POSIXACL;
 157 #endif
 158         ret = jffs2_do_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
 159
 160         if (ret) {
 161                 /* Failure case... */
 162                 up_write(&sb->s_umount);
 163                 deactivate_super(sb);
 164                 return ERR_PTR(ret);
 165         }
 166
 167         sb->s_flags |= MS_ACTIVE;
 168         return sb;
 169
 170  out_put:
 171         kfree(c);
 172         put_mtd_device(mtd);
 173
 174         return sb;
 175 }
 176
 177 static struct super_block *jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
 178                                               int flags, const char *dev_name,
 179                                               void *data, int mtdnr)
 180 {
 181         struct mtd_info *mtd;
 182
 183         mtd = get_mtd_device(NULL, mtdnr);
 184         if (!mtd) {
 185                 D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
 186                 return ERR_PTR(-EINVAL);
 187         }
 188
 189         return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
 190 }
 191
 192 static struct super_block *jffs2_get_sb(struct file_system_type *fs_type,
 193                                         int flags, const char *dev_name,
 194                                         void *data)
 195 {
 196         int err;
 197         struct nameidata nd;
 198         int mtdnr;
 199
 200         if (!dev_name)
 201                 return ERR_PTR(-EINVAL);
 202
 203         D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
 204
 205         /* The preferred way of mounting in future; especially when
 206            CONFIG_BLK_DEV is implemented - we specify the underlying
 207            MTD device by number or by name, so that we don't require
 208            block device support to be present in the kernel. */
 209
 210         /* FIXME: How to do the root fs this way? */
 211
 212         if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
 213                 /* Probably mounting without the blkdev crap */
 214                 if (dev_name[3] == ':') {
 215                         struct mtd_info *mtd;
 216
 217                         /* Mount by MTD device name */
 218                         D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name \"%s\"\n", dev_name+4));
 219                         for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
 220                                 mtd = get_mtd_device(NULL, mtdnr);
 221                                 if (mtd) {
 222                                         if (!strcmp(mtd->name, dev_name+4))
 223                                                 return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
 224                                         put_mtd_device(mtd);
 225                                 }
 226                         }
 227                         printk(KERN_NOTICE "jffs2_get_sb(): MTD device with name \"%s\" not found.\n", dev_name+4);
 228                 } else if (isdigit(dev_name[3])) {
 229                         /* Mount by MTD device number name */
 230                         char *endptr;
 231
 232                         mtdnr = simple_strtoul(dev_name+3, &endptr, 0);
 233                         if (!*endptr) {
 234                                 /* It was a valid number */
 235                                 D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, mtdnr %d\n", mtdnr));
 236                                 return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
 237                         }
 238                 }
 239         }
 240
 241         /* Try the old way - the hack where we allowed users to mount
 242            /dev/mtdblock$(n) but didn't actually _use_ the blkdev */
 243
 244         err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
 245
 246         D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode %p\n",
 247                   err, nd.dentry->d_inode));
 248
 249         if (err)
 250                 return ERR_PTR(err);
 251
 252         err = -EINVAL;
 253
 254         if (!S_ISBLK(nd.dentry->d_inode->i_mode))
 255                 goto out;
 256
 257         if (nd.mnt->mnt_flags & MNT_NODEV) {
 258                 err = -EACCES;
 259                 goto out;
 260         }
 261
 262         if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
 263                 if (!(flags & MS_SILENT))
 264                         printk(KERN_NOTICE "Attempt to mount non-MTD device \"%s\" as JFFS2\n",
 265                                dev_name);
 266                 goto out;
 267         }
 268
 269         mtdnr = iminor(nd.dentry->d_inode);
 270         path_release(&nd);
 271
 272         return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
 273
 274 out:
 275         path_release(&nd);
 276         return ERR_PTR(err);
 277 }
 278
 279 static void jffs2_put_super (struct super_block *sb)
 280 {
 281         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 282
 283         D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 284
 285         down(&c->alloc_sem);
 286         jffs2_flush_wbuf_pad(c);
 287         up(&c->alloc_sem);
 288
 289         jffs2_sum_exit(c);
 290
 291         jffs2_free_ino_caches(c);
 292         jffs2_free_raw_node_refs(c);
 293         if (jffs2_blocks_use_vmalloc(c))
 294                 vfree(c->blocks);
 295         else
 296                 kfree(c->blocks);
 297         jffs2_flash_cleanup(c);
 298         kfree(c->inocache_list);
 299         jffs2_clear_xattr_subsystem(c);
 300         if (c->mtd->sync)
 301                 c->mtd->sync(c->mtd);
 302
 303         D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 304 }
 305
 306 static void jffs2_kill_sb(struct super_block *sb)
 307 {
 308         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 309         if (!(sb->s_flags & MS_RDONLY))
 310                 jffs2_stop_garbage_collect_thread(c);
 311         generic_shutdown_super(sb);
 312         put_mtd_device(c->mtd);
 313         kfree(c);
 314 }
 315
 316 static struct file_system_type jffs2_fs_type = {
 317         .owner =        THIS_MODULE,
 318         .name =         "jffs2",
 319         .get_sb =       jffs2_get_sb,
 320         .kill_sb =      jffs2_kill_sb,
 321 };
 322
 323 static int __init init_jffs2_fs(void)
 324 {
 325         int ret;
 326
 327         /* Paranoia checks for on-medium structures. If we ask GCC
 328            to pack them with __attribute__((packed)) then it _also_
 329            assumes that they're not aligned -- so it emits crappy
 330            code on some architectures. Ideally we want an attribute
 331            which means just 'no padding', without the alignment
 332            thing. But GCC doesn't have that -- we have to just
 333            hope the structs are the right sizes, instead. */
 334         BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 335         BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 336         BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 337         BUG_ON(sizeof(struct jffs2_raw_summary) != 32);
 338
 339         printk(KERN_INFO "JFFS2 version 2.2."
 340 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 341                " (NAND)"
 342 #endif
 343 #ifdef CONFIG_JFFS2_SUMMARY
 344                " (SUMMARY) "
 345 #endif
 346                " (C) 2001-2006 Red Hat, Inc.\n");
 347
 348         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 349                                              sizeof(struct jffs2_inode_info),
 350                                              0, (SLAB_RECLAIM_ACCOUNT|
 351                                                 SLAB_MEM_SPREAD),
 352                                              jffs2_i_init_once, NULL);
 353         if (!jffs2_inode_cachep) {
 354                 printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 355                 return -ENOMEM;
 356         }
 357         ret = jffs2_compressors_init();
 358         if (ret) {
 359                 printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
 360                 goto out;
 361         }
 362         ret = jffs2_create_slab_caches();
 363         if (ret) {
 364                 printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 365                 goto out_compressors;
 366         }
 367         ret = register_filesystem(&jffs2_fs_type);
 368         if (ret) {
 369                 printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
 370                 goto out_slab;
 371         }
 372         return 0;
 373
 374  out_slab:
 375         jffs2_destroy_slab_caches();
 376  out_compressors:
 377         jffs2_compressors_exit();
 378  out:
 379         kmem_cache_destroy(jffs2_inode_cachep);
 380         return ret;
 381 }
 382
 383 static void __exit exit_jffs2_fs(void)
 384 {
 385         unregister_filesystem(&jffs2_fs_type);
 386         jffs2_destroy_slab_caches();
 387         jffs2_compressors_exit();
 388         kmem_cache_destroy(jffs2_inode_cachep);
 389 }
 390
 391 module_init(init_jffs2_fs);
 392 module_exit(exit_jffs2_fs);
 393
 394 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 395 MODULE_AUTHOR("Red Hat, Inc.");
 396 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 397                        // the sake of this tag. It's Free Software.