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