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
 155         ret = jffs2_do_fill_super(sb, data, (flags&MS_VERBOSE)?1:0);
 156
 157         if (ret) {
 158                 /* Failure case... */
 159                 up_write(&sb->s_umount);
 160                 deactivate_super(sb);
 161                 return ERR_PTR(ret);
 162         }
 163
 164         sb->s_flags |= MS_ACTIVE;
 165         return sb;
 166
 167  out_put:
 168         kfree(c);
 169         put_mtd_device(mtd);
 170
 171         return sb;
 172 }
 173
 174 static struct super_block *jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
 175                                               int flags, const char *dev_name,
 176                                               void *data, int mtdnr)
 177 {
 178         struct mtd_info *mtd;
 179
 180         mtd = get_mtd_device(NULL, mtdnr);
 181         if (!mtd) {
 182                 D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
 183                 return ERR_PTR(-EINVAL);
 184         }
 185
 186         return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
 187 }
 188
 189 static struct super_block *jffs2_get_sb(struct file_system_type *fs_type,
 190                                         int flags, const char *dev_name,
 191                                         void *data)
 192 {
 193         int err;
 194         struct nameidata nd;
 195         int mtdnr;
 196
 197         if (!dev_name)
 198                 return ERR_PTR(-EINVAL);
 199
 200         D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
 201
 202         /* The preferred way of mounting in future; especially when
 203            CONFIG_BLK_DEV is implemented - we specify the underlying
 204            MTD device by number or by name, so that we don't require
 205            block device support to be present in the kernel. */
 206
 207         /* FIXME: How to do the root fs this way? */
 208
 209         if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
 210                 /* Probably mounting without the blkdev crap */
 211                 if (dev_name[3] == ':') {
 212                         struct mtd_info *mtd;
 213
 214                         /* Mount by MTD device name */
 215                         D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name \"%s\"\n", dev_name+4));
 216                         for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
 217                                 mtd = get_mtd_device(NULL, mtdnr);
 218                                 if (mtd) {
 219                                         if (!strcmp(mtd->name, dev_name+4))
 220                                                 return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
 221                                         put_mtd_device(mtd);
 222                                 }
 223                         }
 224                         printk(KERN_NOTICE "jffs2_get_sb(): MTD device with name \"%s\" not found.\n", dev_name+4);
 225                 } else if (isdigit(dev_name[3])) {
 226                         /* Mount by MTD device number name */
 227                         char *endptr;
 228
 229                         mtdnr = simple_strtoul(dev_name+3, &endptr, 0);
 230                         if (!*endptr) {
 231                                 /* It was a valid number */
 232                                 D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, mtdnr %d\n", mtdnr));
 233                                 return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
 234                         }
 235                 }
 236         }
 237
 238         /* Try the old way - the hack where we allowed users to mount
 239            /dev/mtdblock$(n) but didn't actually _use_ the blkdev */
 240
 241         err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
 242
 243         D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode %p\n",
 244                   err, nd.dentry->d_inode));
 245
 246         if (err)
 247                 return ERR_PTR(err);
 248
 249         err = -EINVAL;
 250
 251         if (!S_ISBLK(nd.dentry->d_inode->i_mode))
 252                 goto out;
 253
 254         if (nd.mnt->mnt_flags & MNT_NODEV) {
 255                 err = -EACCES;
 256                 goto out;
 257         }
 258
 259         if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
 260                 if (!(flags & MS_VERBOSE)) /* Yes I mean this. Strangely */
 261                         printk(KERN_NOTICE "Attempt to mount non-MTD device \"%s\" as JFFS2\n",
 262                                dev_name);
 263                 goto out;
 264         }
 265
 266         mtdnr = iminor(nd.dentry->d_inode);
 267         path_release(&nd);
 268
 269         return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
 270
 271 out:
 272         path_release(&nd);
 273         return ERR_PTR(err);
 274 }
 275
 276 static void jffs2_put_super (struct super_block *sb)
 277 {
 278         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 279
 280         D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 281
 282         down(&c->alloc_sem);
 283         jffs2_flush_wbuf_pad(c);
 284         up(&c->alloc_sem);
 285
 286         jffs2_sum_exit(c);
 287
 288         jffs2_free_ino_caches(c);
 289         jffs2_free_raw_node_refs(c);
 290         if (jffs2_blocks_use_vmalloc(c))
 291                 vfree(c->blocks);
 292         else
 293                 kfree(c->blocks);
 294         jffs2_flash_cleanup(c);
 295         kfree(c->inocache_list);
 296         if (c->mtd->sync)
 297                 c->mtd->sync(c->mtd);
 298
 299         D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 300 }
 301
 302 static void jffs2_kill_sb(struct super_block *sb)
 303 {
 304         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 305         if (!(sb->s_flags & MS_RDONLY))
 306                 jffs2_stop_garbage_collect_thread(c);
 307         generic_shutdown_super(sb);
 308         put_mtd_device(c->mtd);
 309         kfree(c);
 310 }
 311
 312 static struct file_system_type jffs2_fs_type = {
 313         .owner =        THIS_MODULE,
 314         .name =         "jffs2",
 315         .get_sb =       jffs2_get_sb,
 316         .kill_sb =      jffs2_kill_sb,
 317 };
 318
 319 static int __init init_jffs2_fs(void)
 320 {
 321         int ret;
 322
 323         printk(KERN_INFO "JFFS2 version 2.2."
 324 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 325                " (NAND)"
 326 #endif
 327 #ifdef CONFIG_JFFS2_SUMMARY
 328                " (SUMMARY) "
 329 #endif
 330                " (C) 2001-2003 Red Hat, Inc.\n");
 331
 332         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 333                                              sizeof(struct jffs2_inode_info),
 334                                              0, SLAB_RECLAIM_ACCOUNT,
 335                                              jffs2_i_init_once, NULL);
 336         if (!jffs2_inode_cachep) {
 337                 printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 338                 return -ENOMEM;
 339         }
 340         ret = jffs2_compressors_init();
 341         if (ret) {
 342                 printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
 343                 goto out;
 344         }
 345         ret = jffs2_create_slab_caches();
 346         if (ret) {
 347                 printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 348                 goto out_compressors;
 349         }
 350         ret = register_filesystem(&jffs2_fs_type);
 351         if (ret) {
 352                 printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
 353                 goto out_slab;
 354         }
 355         return 0;
 356
 357  out_slab:
 358         jffs2_destroy_slab_caches();
 359  out_compressors:
 360         jffs2_compressors_exit();
 361  out:
 362         kmem_cache_destroy(jffs2_inode_cachep);
 363         return ret;
 364 }
 365
 366 static void __exit exit_jffs2_fs(void)
 367 {
 368         unregister_filesystem(&jffs2_fs_type);
 369         jffs2_destroy_slab_caches();
 370         jffs2_compressors_exit();
 371         kmem_cache_destroy(jffs2_inode_cachep);
 372 }
 373
 374 module_init(init_jffs2_fs);
 375 module_exit(exit_jffs2_fs);
 376
 377 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 378 MODULE_AUTHOR("Red Hat, Inc.");
 379 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 380                        // the sake of this tag. It's Free Software.