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