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@redhat.com>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  * $Id: super.c,v 1.90 2003/10/11 11:47:23 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 "nodelist.h"
  28
  29 static void jffs2_put_super(struct super_block *);
  30
  31 static kmem_cache_t *jffs2_inode_cachep;
  32
  33 static struct inode *jffs2_alloc_inode(struct super_block *sb)
  34 {
  35         struct jffs2_inode_info *ei;
  36         ei = (struct jffs2_inode_info *)kmem_cache_alloc(jffs2_inode_cachep, SLAB_KERNEL);
  37         if (!ei)
  38                 return NULL;
  39         return &ei->vfs_inode;
  40 }
  41
  42 static void jffs2_destroy_inode(struct inode *inode)
  43 {
  44         kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  45 }
  46
  47 static void jffs2_i_init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
  48 {
  49         struct jffs2_inode_info *ei = (struct jffs2_inode_info *) foo;
  50
  51         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
  52             SLAB_CTOR_CONSTRUCTOR) {
  53                 init_MUTEX_LOCKED(&ei->sem);
  54                 inode_init_once(&ei->vfs_inode);
  55         }
  56 }
  57
  58 static struct super_operations jffs2_super_operations =
  59 {
  60         .alloc_inode =  jffs2_alloc_inode,
  61         .destroy_inode =jffs2_destroy_inode,
  62         .read_inode =   jffs2_read_inode,
  63         .put_super =    jffs2_put_super,
  64         .write_super =  jffs2_write_super,
  65         .statfs =       jffs2_statfs,
  66         .remount_fs =   jffs2_remount_fs,
  67         .clear_inode =  jffs2_clear_inode,
  68         .dirty_inode =  jffs2_dirty_inode,
  69 };
  70
  71 static int jffs2_sb_compare(struct super_block *sb, void *data)
  72 {
  73         struct jffs2_sb_info *p = data;
  74         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  75
  76         /* The superblocks are considered to be equivalent if the underlying MTD
  77            device is the same one */
  78         if (c->mtd == p->mtd) {
  79                 D1(printk(KERN_DEBUG "jffs2_sb_compare: match on device %d (\"%s\")\n", p->mtd->index, p->mtd->name));
  80                 return 1;
  81         } else {
  82                 D1(printk(KERN_DEBUG "jffs2_sb_compare: No match, device %d (\"%s\"), device %d (\"%s\")\n",
  83                           c->mtd->index, c->mtd->name, p->mtd->index, p->mtd->name));
  84                 return 0;
  85         }
  86 }
  87
  88 static int jffs2_sb_set(struct super_block *sb, void *data)
  89 {
  90         struct jffs2_sb_info *p = data;
  91
  92         /* For persistence of NFS exports etc. we use the same s_dev
  93            each time we mount the device, don't just use an anonymous
  94            device */
  95         sb->s_fs_info = p;
  96         p->os_priv = sb;
  97         sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, p->mtd->index);
  98
  99         return 0;
 100 }
 101
 102 static struct super_block *jffs2_get_sb_mtd(struct file_system_type *fs_type,
 103                                               int flags, const char *dev_name,
 104                                               void *data, struct mtd_info *mtd)
 105 {
 106         struct super_block *sb;
 107         struct jffs2_sb_info *c;
 108         int ret;
 109
 110         c = kmalloc(sizeof(*c), GFP_KERNEL);
 111         if (!c)
 112                 return ERR_PTR(-ENOMEM);
 113         memset(c, 0, sizeof(*c));
 114         c->mtd = mtd;
 115
 116         sb = sget(fs_type, jffs2_sb_compare, jffs2_sb_set, c);
 117
 118         if (IS_ERR(sb))
 119                 goto out_put;
 120
 121         if (sb->s_root) {
 122                 /* New mountpoint for JFFS2 which is already mounted */
 123                 D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): Device %d (\"%s\") is already mounted\n",
 124                           mtd->index, mtd->name));
 125                 goto out_put;
 126         }
 127
 128         D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d (\"%s\")\n",
 129                   mtd->index, mtd->name));
 130
 131         sb->s_op = &jffs2_super_operations;
 132         sb->s_flags |= MS_NOATIME;
 133
 134         ret = jffs2_do_fill_super(sb, data, (flags&MS_VERBOSE)?1:0);
 135
 136         if (ret) {
 137                 /* Failure case... */
 138                 up_write(&sb->s_umount);
 139                 deactivate_super(sb);
 140                 return ERR_PTR(ret);
 141         }
 142
 143         sb->s_flags |= MS_ACTIVE;
 144         return sb;
 145
 146  out_put:
 147         kfree(c);
 148         put_mtd_device(mtd);
 149
 150         return sb;
 151 }
 152
 153 static struct super_block *jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
 154                                               int flags, const char *dev_name,
 155                                               void *data, int mtdnr)
 156 {
 157         struct mtd_info *mtd;
 158
 159         mtd = get_mtd_device(NULL, mtdnr);
 160         if (!mtd) {
 161                 D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
 162                 return ERR_PTR(-EINVAL);
 163         }
 164
 165         return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
 166 }
 167
 168 static struct super_block *jffs2_get_sb(struct file_system_type *fs_type,
 169                                         int flags, const char *dev_name,
 170                                         void *data)
 171 {
 172         int err;
 173         struct nameidata nd;
 174         int mtdnr;
 175
 176         if (!dev_name)
 177                 return ERR_PTR(-EINVAL);
 178
 179         D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
 180
 181         /* The preferred way of mounting in future; especially when
 182            CONFIG_BLK_DEV is implemented - we specify the underlying
 183            MTD device by number or by name, so that we don't require
 184            block device support to be present in the kernel. */
 185
 186         /* FIXME: How to do the root fs this way? */
 187
 188         if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
 189                 /* Probably mounting without the blkdev crap */
 190                 if (dev_name[3] == ':') {
 191                         struct mtd_info *mtd;
 192
 193                         /* Mount by MTD device name */
 194                         D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name \"%s\"\n", dev_name+4));
 195                         for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
 196                                 mtd = get_mtd_device(NULL, mtdnr);
 197                                 if (mtd) {
 198                                         if (!strcmp(mtd->name, dev_name+4))
 199                                                 return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
 200                                         put_mtd_device(mtd);
 201                                 }
 202                         }
 203                         printk(KERN_NOTICE "jffs2_get_sb(): MTD device with name \"%s\" not found.\n", dev_name+4);
 204                 } else if (isdigit(dev_name[3])) {
 205                         /* Mount by MTD device number name */
 206                         char *endptr;
 207
 208                         mtdnr = simple_strtoul(dev_name+3, &endptr, 0);
 209                         if (!*endptr) {
 210                                 /* It was a valid number */
 211                                 D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, mtdnr %d\n", mtdnr));
 212                                 return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
 213                         }
 214                 }
 215         }
 216
 217         /* Try the old way - the hack where we allowed users to mount
 218            /dev/mtdblock$(n) but didn't actually _use_ the blkdev */
 219
 220         err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
 221
 222         D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode %p\n",
 223                   err, nd.dentry->d_inode));
 224
 225         if (err)
 226                 return ERR_PTR(err);
 227
 228         err = -EINVAL;
 229
 230         if (!S_ISBLK(nd.dentry->d_inode->i_mode))
 231                 goto out;
 232
 233         if (nd.mnt->mnt_flags & MNT_NODEV) {
 234                 err = -EACCES;
 235                 goto out;
 236         }
 237
 238         if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
 239                 if (!(flags & MS_VERBOSE)) /* Yes I mean this. Strangely */
 240                         printk(KERN_NOTICE "Attempt to mount non-MTD device \"%s\" as JFFS2\n",
 241                                dev_name);
 242                 goto out;
 243         }
 244
 245         mtdnr = iminor(nd.dentry->d_inode);
 246         path_release(&nd);
 247
 248         return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
 249
 250 out:
 251         path_release(&nd);
 252         return ERR_PTR(err);
 253 }
 254
 255 static void jffs2_put_super (struct super_block *sb)
 256 {
 257         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 258
 259         D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 260
 261         if (!(sb->s_flags & MS_RDONLY))
 262                 jffs2_stop_garbage_collect_thread(c);
 263         down(&c->alloc_sem);
 264         jffs2_flush_wbuf_pad(c);
 265         up(&c->alloc_sem);
 266         jffs2_free_ino_caches(c);
 267         jffs2_free_raw_node_refs(c);
 268         kfree(c->blocks);
 269         jffs2_nand_flash_cleanup(c);
 270         kfree(c->inocache_list);
 271         if (c->mtd->sync)
 272                 c->mtd->sync(c->mtd);
 273
 274         D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 275 }
 276
 277 static void jffs2_kill_sb(struct super_block *sb)
 278 {
 279         struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 280         generic_shutdown_super(sb);
 281         put_mtd_device(c->mtd);
 282         kfree(c);
 283 }
 284
 285 static struct file_system_type jffs2_fs_type = {
 286         .owner =        THIS_MODULE,
 287         .name =         "jffs2",
 288         .get_sb =       jffs2_get_sb,
 289         .kill_sb =      jffs2_kill_sb,
 290 };
 291
 292 static int __init init_jffs2_fs(void)
 293 {
 294         int ret;
 295
 296         printk(KERN_INFO "JFFS2 version 2.2."
 297 #ifdef CONFIG_FS_JFFS2_NAND
 298                " (NAND)"
 299 #endif
 300                " (C) 2001-2003 Red Hat, Inc.\n");
 301
 302         jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 303                                              sizeof(struct jffs2_inode_info),
 304                                              0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
 305                                              jffs2_i_init_once, NULL);
 306         if (!jffs2_inode_cachep) {
 307                 printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
 308                 return -ENOMEM;
 309         }
 310         ret = jffs2_zlib_init();
 311         if (ret) {
 312                 printk(KERN_ERR "JFFS2 error: Failed to initialise zlib workspaces\n");
 313                 goto out;
 314         }
 315         ret = jffs2_create_slab_caches();
 316         if (ret) {
 317                 printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
 318                 goto out_zlib;
 319         }
 320         ret = register_filesystem(&jffs2_fs_type);
 321         if (ret) {
 322                 printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
 323                 goto out_slab;
 324         }
 325         return 0;
 326
 327  out_slab:
 328         jffs2_destroy_slab_caches();
 329  out_zlib:
 330         jffs2_zlib_exit();
 331  out:
 332         return ret;
 333 }
 334
 335 static void __exit exit_jffs2_fs(void)
 336 {
 337         unregister_filesystem(&jffs2_fs_type);
 338         jffs2_destroy_slab_caches();
 339         jffs2_zlib_exit();
 340         kmem_cache_destroy(jffs2_inode_cachep);
 341 }
 342
 343 module_init(init_jffs2_fs);
 344 module_exit(exit_jffs2_fs);
 345
 346 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 347 MODULE_AUTHOR("Red Hat, Inc.");
 348 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 349                        // the sake of this tag. It's Free Software.