fs/jffs2.org/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@redhat.com>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  * $Id: super.c,v 1.99 2004/08/24 07:59:57 dwmw2 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_LOCKED(&ei->sem);
  55                 inode_init_once(&ei->vfs_inode);
  56         }
  57 }
  58
  59 static struct super_operations jffs2_super_operations =
  60 {
  61         .alloc_inode =  jffs2_alloc_inode,
  62         .destroy_inode =jffs2_destroy_inode,
  63         .read_inode =   jffs2_read_inode,
  64         .put_super =    jffs2_put_super,
  65         .write_super =  jffs2_write_super,
  66         .statfs =       jffs2_statfs,
  67         .remount_fs =   jffs2_remount_fs,
  68         .clear_inode =  jffs2_clear_inode,
  69         .dirty_inode =  jffs2_dirty_inode,
  70 };
  71
  72 static int jffs2_sb_compare(struct super_block *sb, void *data)
  73 {
  74         struct jffs2_sb_info *p = data;
  75         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  76
  77         /* The superblocks are considered to be equivalent if the underlying MTD
  78            device is the same one */
  79         if (c->mtd == p->mtd) {
  80                 D1(printk(KERN_DEBUG "jffs2_sb_compare: match on device %d (\"%s\")\n", p->mtd->index, p->mtd->name));
  81                 return 1;
  82         } else {
  83                 D1(printk(KERN_DEBUG "jffs2_sb_compare: No match, device %d (\"%s\"), device %d (\"%s\")\n",
  84                           c->mtd->index, c->mtd->name, p->mtd->index, p->mtd->name));
  85                 return 0;
  86         }
  87 }
  88
  89 static int jffs2_sb_set(struct super_block *sb, void *data)
  90 {
  91         struct jffs2_sb_info *p = data;
  92
  93         /* For persistence of NFS exports etc. we use the same s_dev
  94            each time we mount the device, don't just use an anonymous
  95            device */
  96         sb->s_fs_info = p;
  97         p->os_priv = sb;
  98         sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, p->mtd->index);
  99
 100         return 0;
 101 }
 102
 103 static struct super_block *jffs2_get_sb_mtd(struct file_system_type *fs_type,
 104                                               int flags, const char *dev_name,
 105                                               void *data, struct mtd_info *mtd)
 106 {
 107         struct super_block *sb;
 108         struct jffs2_sb_info *c;
 109         int ret;
 110
 111         c = kmalloc(sizeof(*c), GFP_KERNEL);
 112         if (!c)
 113                 return ERR_PTR(-ENOMEM);
 114         memset(c, 0, sizeof(*c));
 115         c->mtd = mtd;
 116
 117         sb = sget(fs_type, jffs2_sb_compare, jffs2_sb_set, c);
 118
 119         if (IS_ERR(sb))
 120                 goto out_put;
 121
 122         if (sb->s_root) {
 123                 /* New mountpoint for JFFS2 which is already mounted */
 124                 D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): Device %d (\"%s\") is already mounted\n",
 125                           mtd->index, mtd->name));
 126                 goto out_put;
 127         }
 128
 129         D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d (\"%s\")\n",
 130                   mtd->index, mtd->name));
 131
 132         sb->s_op = &jffs2_super_operations;
 133         sb->s_flags = flags | MS_NOATIME;
 134
 135         ret = jffs2_do_fill_super(sb, data, (flags&MS_VERBOSE)?1:0);
 136
 137         if (ret) {
 138                 /* Failure case... */
 139                 up_write(&sb->s_umount);
 140                 deactivate_super(sb);
 141                 return ERR_PTR(ret);
 142         }
 143
 144         sb->s_flags |= MS_ACTIVE;
 145         return sb;
 146
 147  out_put:
 148         kfree(c);
 149         put_mtd_device(mtd);
 150
 151         return sb;
 152 }
 153
 154 static struct super_block *jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
 155                                               int flags, const char *dev_name,
 156                                               void *data, int mtdnr)
 157 {
 158         struct mtd_info *mtd;
 159
 160         mtd = get_mtd_device(NULL, mtdnr);
 161         if (!mtd) {
 162                 D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
 163                 return ERR_PTR(-EINVAL);
 164         }
 165
 166         return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
 167 }
 168
 169 static struct super_block *jffs2_get_sb(struct file_system_type *fs_type,
 170                                         int flags, const char *dev_name,
 171                                         void *data)
 172 {
 173         int err;
 174         struct nameidata nd;
 175         int mtdnr;
 176
 177         if (!dev_name)
 178                 return ERR_PTR(-EINVAL);
 179
 180         D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
 181
 182         /* The preferred way of mounting in future; especially when
 183            CONFIG_BLK_DEV is implemented - we specify the underlying
 184            MTD device by number or by name, so that we don't require
 185            block device support to be present in the kernel. */
 186
 187         /* FIXME: How to do the root fs this way? */
 188
 189         if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
 190                 /* Probably mounting without the blkdev crap */
 191                 if (dev_name[3] == ':') {
 192                         struct mtd_info *mtd;
 193
 194                         /* Mount by MTD device name */
 195                         D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name \"%s\"\n", dev_name+4));
 196                         for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
 197                                 mtd = get_mtd_device(NULL, mtdnr);
 198                                 if (mtd) {
 199                                         if (!strcmp(mtd->name, dev_name+4))
 200                                                 return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
 201                                         put_mtd_device(mtd);
 202                                 }
 203                         }
 204                         printk(KERN_NOTICE "jffs2_get_sb(): MTD device with name \"%s\" not found.\n", dev_name+4);
 205                 } else if (isdigit(dev_name[3])) {
 206                         /* Mount by MTD device number name */
 207                         char *endptr;
 208
 209                         mtdnr = simple_strtoul(dev_name+3, &endptr, 0);
 210                         if (!*endptr) {
 211                                 /* It was a valid number */
 212                                 D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, mtdnr %d\n", mtdnr));
 213                                 return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
 214                         }
 215                 }
 216         }
 217
 218         /* Try the old way - the hack where we allowed users to mount
 219            /dev/mtdblock$(n) but didn't actually _use_ the blkdev */
 220
 221         err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
 222
 223         D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode %p\n",
 224                   err, nd.dentry->d_inode));
 225
 226         if (err)
 227                 return ERR_PTR(err);
 228
 229         err = -EINVAL;
 230
 231         if (!S_ISBLK(nd.dentry->d_inode->i_mode))
 232                 goto out;
 233
 234         if (nd.mnt->mnt_flags & MNT_NODEV) {
 235                 err = -EACCES;
 236                 goto out;
 237         }
 238
 239         if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
 240                 if (!(flags & MS_VERBOSE)) /* Yes I mean this. Strangely */
 241                         printk(KERN_NOTICE "Attempt to mount non-MTD device \"%s\" as JFFS2\n",
 242                                dev_name);
 243                 goto out;
 244         }
 245
 246         mtdnr = iminor(nd.dentry->d_inode);
 247         path_release(&nd);
 248
 249         return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
 250
 251 out:
 252         path_release(&nd);
 253         return ERR_PTR(err);
 254 }
 255
 256 static void jffs2_put_super (struct super_block *sb)
 257 {
 258         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 259
 260         D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 261
 262         if (!(sb->s_flags & MS_RDONLY))
 263                 jffs2_stop_garbage_collect_thread(c);
 264         down(&c->alloc_sem);
 265         jffs2_flush_wbuf_pad(c);
 266         up(&c->alloc_sem);
 267         jffs2_free_ino_caches(c);
 268         jffs2_free_raw_node_refs(c);
 269         kfree(c->blocks);
 270         jffs2_flash_cleanup(c);
 271         kfree(c->inocache_list);
 272         if (c->mtd->sync)
 273                 c->mtd->sync(c->mtd);
 274
 275         D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 276 }
 277
 278 static void jffs2_kill_sb(struct super_block *sb)
 279 {
 280         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 281         generic_shutdown_super(sb);
 282         put_mtd_device(c->mtd);
 283         kfree(c);
 284 }
 285
 286 static struct file_system_type jffs2_fs_type = {
 287         .owner =        THIS_MODULE,
 288         .name =         "jffs2",
 289         .get_sb =       jffs2_get_sb,
 290         .kill_sb =      jffs2_kill_sb,
 291         .fs_flags =     FS_REQUIRES_DEV,
 292 };
 293
 294 static int __init init_jffs2_fs(void)
 295 {
 296         int ret;
 297
 298         printk(KERN_INFO "JFFS2 version 2.2."
 299 #ifdef CONFIG_JFFS2_FS_NAND
 300                " (NAND)"
 301 #endif
 302                " (C) 2001-2003 Red Hat, Inc.\n");
 303
 304         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 305                                              sizeof(struct jffs2_inode_info),
 306                                              0, SLAB_RECLAIM_ACCOUNT,
 307                                              jffs2_i_init_once, NULL);
 308         if (!jffs2_inode_cachep) {
 309                 printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 310                 return -ENOMEM;
 311         }
 312         ret = jffs2_compressors_init();
 313         if (ret) {
 314                 printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
 315                 goto out;
 316         }
 317         ret = jffs2_create_slab_caches();
 318         if (ret) {
 319                 printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 320                 goto out_compressors;
 321         }
 322         ret = register_filesystem(&jffs2_fs_type);
 323         if (ret) {
 324                 printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
 325                 goto out_slab;
 326         }
 327         return 0;
 328
 329  out_slab:
 330         jffs2_destroy_slab_caches();
 331  out_compressors:
 332         jffs2_compressors_exit();
 333  out:
 334         kmem_cache_destroy(jffs2_inode_cachep);
 335         return ret;
 336 }
 337
 338 static void __exit exit_jffs2_fs(void)
 339 {
 340         unregister_filesystem(&jffs2_fs_type);
 341         jffs2_destroy_slab_caches();
 342         jffs2_compressors_exit();
 343         kmem_cache_destroy(jffs2_inode_cachep);
 344 }
 345
 346 module_init(init_jffs2_fs);
 347 module_exit(exit_jffs2_fs);
 348
 349 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 350 MODULE_AUTHOR("Red Hat, Inc.");
 351 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 352                        // the sake of this tag. It's Free Software.