super.c

ARM 嵌入式 系统 设计与实例开发 实验教材 二源码

{
    int retval;
    struct inode * inode;
    struct cpu_key key;
    INITIALIZE_PATH (path);
    struct reiserfs_dir_entry de;
    __u32 hash = DEFAULT_HASH;

    inode = s->s_root->d_inode;

    while (1) {
	make_cpu_key (&key, inode, ~0, TYPE_DIRENTRY, 3);
	retval = search_by_entry_key (s, &key, &path, &de);
	if (retval == IO_ERROR) {
	    pathrelse (&path);
	    return UNSET_HASH ;
	}
	if (retval == NAME_NOT_FOUND)
	    de.de_entry_num --;
	set_de_name_and_namelen (&de);
	if (deh_offset( &(de.de_deh[de.de_entry_num]) ) == DOT_DOT_OFFSET) {
	    /* allow override in this case */
	    if (reiserfs_rupasov_hash(s)) {
		hash = YURA_HASH ;
	    }
	    reiserfs_warning("reiserfs: FS seems to be empty, autodetect "
	                     "is using the default hash\n");
	    break;
	}
	if (GET_HASH_VALUE(yura_hash (de.de_name, de.de_namelen)) == 
	    GET_HASH_VALUE(keyed_hash (de.de_name, de.de_namelen))) {
	    reiserfs_warning ("reiserfs: Could not detect hash function "
			      "please mount with -o hash={tea,rupasov,r5}\n") ;
	    hash = UNSET_HASH ;
	    break;
	}
	if (GET_HASH_VALUE( deh_offset(&(de.de_deh[de.de_entry_num])) ) ==
	    GET_HASH_VALUE (yura_hash (de.de_name, de.de_namelen)))
	    hash = YURA_HASH;
	else
	    hash = TEA_HASH;
	break;
    }

    pathrelse (&path);
    return hash;
}

// finds out which hash names are sorted with
static int what_hash (struct super_block * s)
{
    __u32 code;

    code = sb_hash_function_code(SB_DISK_SUPER_BLOCK(s));

    /* reiserfs_hash_detect() == true if any of the hash mount options
    ** were used.  We must check them to make sure the user isn't
    ** using a bad hash value
    */
    if (code == UNSET_HASH || reiserfs_hash_detect(s))
	code = find_hash_out (s);

    if (code != UNSET_HASH && reiserfs_hash_detect(s)) {
	/* detection has found the hash, and we must check against the 
	** mount options 
	*/
	if (reiserfs_rupasov_hash(s) && code != YURA_HASH) {
	    printk("REISERFS: Error, tea hash detected, "
		   "unable to force rupasov hash\n") ;
	    code = UNSET_HASH ;
	} else if (reiserfs_tea_hash(s) && code != TEA_HASH) {
	    printk("REISERFS: Error, rupasov hash detected, "
		   "unable to force tea hash\n") ;
	    code = UNSET_HASH ;
	} else if (reiserfs_r5_hash(s) && code != R5_HASH) {
	    printk("REISERFS: Error, r5 hash detected, "
		   "unable to force r5 hash\n") ;
	    code = UNSET_HASH ;
	} 
    } else { 
        /* find_hash_out was not called or could not determine the hash */
	if (reiserfs_rupasov_hash(s)) {
	    code = YURA_HASH ;
	} else if (reiserfs_tea_hash(s)) {
	    code = TEA_HASH ;
	} else if (reiserfs_r5_hash(s)) {
	    code = R5_HASH ;
	} 
    }

    /* if we are mounted RW, and we have a new valid hash code, update 
    ** the super
    */
    if (code != UNSET_HASH && 
	!(s->s_flags & MS_RDONLY) && 
        code != sb_hash_function_code(SB_DISK_SUPER_BLOCK(s))) {
        set_sb_hash_function_code(SB_DISK_SUPER_BLOCK(s), code);
    }
    return code;
}

// return pointer to appropriate function
static hashf_t hash_function (struct super_block * s)
{
    switch (what_hash (s)) {
    case TEA_HASH:
	reiserfs_warning ("Using tea hash to sort names\n");
	return keyed_hash;
    case YURA_HASH:
	reiserfs_warning ("Using rupasov hash to sort names\n");
	return yura_hash;
    case R5_HASH:
	reiserfs_warning ("Using r5 hash to sort names\n");
	return r5_hash;
    }
    return NULL;
}

// this is used to set up correct value for old partitions
int function2code (hashf_t func)
{
    if (func == keyed_hash)
	return TEA_HASH;
    if (func == yura_hash)
	return YURA_HASH;
    if (func == r5_hash)
	return R5_HASH;

    BUG() ; // should never happen 

    return 0;
}

//
// a portion of this function, particularly the VFS interface portion,
// was derived from minix or ext2's analog and evolved as the
// prototype did. You should be able to tell which portion by looking
// at the ext2 code and comparing. It's subfunctions contain no code
// used as a template unless they are so labeled.
//
static struct super_block * reiserfs_read_super (struct super_block * s, void * data, int silent)
{
    int size;
    struct inode *root_inode;
    kdev_t dev = s->s_dev;
    int j;
    extern int *blksize_size[];
    struct reiserfs_transaction_handle th ;
    int old_format = 0;
    unsigned long blocks;
    int jinit_done = 0 ;
    struct reiserfs_iget4_args args ;
    int old_magic;
    struct reiserfs_super_block * rs;


    memset (&s->u.reiserfs_sb, 0, sizeof (struct reiserfs_sb_info));

    if (parse_options ((char *) data, &(s->u.reiserfs_sb.s_mount_opt), &blocks) == 0) {
	return NULL;
    }

    if (blocks) {
  	printk("reserfs: resize option for remount only\n");
	return NULL;
    }	

    if (blksize_size[MAJOR(dev)] && blksize_size[MAJOR(dev)][MINOR(dev)] != 0) {
	/* as blocksize is set for partition we use it */
	size = blksize_size[MAJOR(dev)][MINOR(dev)];
    } else {
	size = BLOCK_SIZE;
	set_blocksize (s->s_dev, BLOCK_SIZE);
    }

    /* read block (64-th 1k block), which can contain reiserfs super block */
    if (read_super_block (s, size, REISERFS_DISK_OFFSET_IN_BYTES)) {
	// try old format (undistributed bitmap, super block in 8-th 1k block of a device)
	if (read_super_block (s, size, REISERFS_OLD_DISK_OFFSET_IN_BYTES)) 
	    goto error;
	else
	    old_format = 1;
    }

    s->u.reiserfs_sb.s_mount_state = SB_REISERFS_STATE(s);
    s->u.reiserfs_sb.s_mount_state = REISERFS_VALID_FS ;

    if (old_format ? read_old_bitmaps(s) : read_bitmaps(s)) { 
	printk ("reiserfs_read_super: unable to read bitmap\n");
	goto error;
    }
#ifdef CONFIG_REISERFS_CHECK
    printk("reiserfs:warning: CONFIG_REISERFS_CHECK is set ON\n");
    printk("reiserfs:warning: - it is slow mode for debugging.\n");
#endif

    // set_device_ro(s->s_dev, 1) ;
    if (journal_init(s)) {
	printk("reiserfs_read_super: unable to initialize journal space\n") ;
	goto error ;
    } else {
	jinit_done = 1 ; /* once this is set, journal_release must be called
			 ** if we error out of the mount 
			 */
    }
    if (reread_meta_blocks(s)) {
	printk("reiserfs_read_super: unable to reread meta blocks after journal init\n") ;
	goto error ;
    }

    if (replay_only (s))
	goto error;

    if (is_read_only(s->s_dev) && !(s->s_flags & MS_RDONLY)) {
        printk("clm-7000: Detected readonly device, marking FS readonly\n") ;
	s->s_flags |= MS_RDONLY ;
    }
    args.objectid = REISERFS_ROOT_PARENT_OBJECTID ;
    root_inode = iget4 (s, REISERFS_ROOT_OBJECTID, 0, (void *)(&args));
    if (!root_inode) {
	printk ("reiserfs_read_super: get root inode failed\n");
	goto error;
    }

    s->s_root = d_alloc_root(root_inode);  
    if (!s->s_root) {
	iput(root_inode);
	goto error;
    }

    // define and initialize hash function
    s->u.reiserfs_sb.s_hash_function = hash_function (s);
    if (s->u.reiserfs_sb.s_hash_function == NULL) {
      dput(s->s_root) ;
      s->s_root = NULL ;
      goto error ;
    }

    rs = SB_DISK_SUPER_BLOCK (s);
    old_magic = strncmp (rs->s_magic,  REISER2FS_SUPER_MAGIC_STRING,
                           strlen ( REISER2FS_SUPER_MAGIC_STRING));
    if (!old_magic)
	set_bit(REISERFS_3_6, &(s->u.reiserfs_sb.s_properties));
    else
	set_bit(REISERFS_3_5, &(s->u.reiserfs_sb.s_properties));

    if (!(s->s_flags & MS_RDONLY)) {

	journal_begin(&th, s, 1) ;
	reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1) ;

        set_sb_state( rs, REISERFS_ERROR_FS );

        if ( old_magic ) {
	    // filesystem created under 3.5.x found
	    if (convert_reiserfs (s)) {
		reiserfs_warning("reiserfs: converting 3.5.x filesystem to the new format\n") ;
		// after this 3.5.x will not be able to mount this partition
		memcpy (rs->s_magic, REISER2FS_SUPER_MAGIC_STRING, 
			sizeof (REISER2FS_SUPER_MAGIC_STRING));

		reiserfs_convert_objectid_map_v1(s) ;
		set_bit(REISERFS_3_6, &(s->u.reiserfs_sb.s_properties));
		clear_bit(REISERFS_3_5, &(s->u.reiserfs_sb.s_properties));
	    } else {
		reiserfs_warning("reiserfs: using 3.5.x disk format\n") ;
	    }
	}

	journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB (s));
	journal_end(&th, s, 1) ;
	
	/* look for files which were to be removed in previous session */
	finish_unfinished (s);

	s->s_dirt = 0;
    } else {
	if ( old_magic ) {
	    reiserfs_warning("reiserfs: using 3.5.x disk format\n") ;
	}
    }
    // mark hash in super block: it could be unset. overwrite should be ok
    set_sb_hash_function_code( rs, function2code(s->u.reiserfs_sb.s_hash_function ) );

    reiserfs_proc_info_init( s );
    reiserfs_proc_register( s, "version", reiserfs_version_in_proc );
    reiserfs_proc_register( s, "super", reiserfs_super_in_proc );
    reiserfs_proc_register( s, "per-level", reiserfs_per_level_in_proc );
    reiserfs_proc_register( s, "bitmap", reiserfs_bitmap_in_proc );
    reiserfs_proc_register( s, "on-disk-super", reiserfs_on_disk_super_in_proc );
    reiserfs_proc_register( s, "oidmap", reiserfs_oidmap_in_proc );
    reiserfs_proc_register( s, "journal", reiserfs_journal_in_proc );
    init_waitqueue_head (&(s->u.reiserfs_sb.s_wait));

    printk("%s\n", reiserfs_get_version_string()) ;
    return s;

 error:
    if (jinit_done) { /* kill the commit thread, free journal ram */
	journal_release_error(NULL, s) ;
    }
    if (SB_DISK_SUPER_BLOCK (s)) {
	for (j = 0; j < SB_BMAP_NR (s); j ++) {
	    if (SB_AP_BITMAP (s))
		brelse (SB_AP_BITMAP (s)[j]);
	}
	if (SB_AP_BITMAP (s))
	    reiserfs_kfree (SB_AP_BITMAP (s), sizeof (struct buffer_head *) * SB_BMAP_NR (s), s);
    }
    if (SB_BUFFER_WITH_SB (s))
	brelse(SB_BUFFER_WITH_SB (s));

    return NULL;
}


//
// a portion of this function, particularly the VFS interface portion,
// was derived from minix or ext2's analog and evolved as the
// prototype did. You should be able to tell which portion by looking
// at the ext2 code and comparing. It's subfunctions contain no code
// used as a template unless they are so labeled.
//
static int reiserfs_statfs (struct super_block * s, struct statfs * buf)
{
  struct reiserfs_super_block * rs = SB_DISK_SUPER_BLOCK (s);
  
				/* changed to accomodate gcc folks.*/
  buf->f_type    =  REISERFS_SUPER_MAGIC;
  buf->f_bsize   = s->s_blocksize;
  buf->f_blocks  = sb_block_count(rs) - sb_bmap_nr(rs) - 1;
  buf->f_bfree   = sb_free_blocks(rs);
  buf->f_bavail  = buf->f_bfree;
  buf->f_files   = -1;
  buf->f_ffree   = -1;
  buf->f_namelen = (REISERFS_MAX_NAME_LEN (s->s_blocksize));
  return 0;
}

static DECLARE_FSTYPE_DEV(reiserfs_fs_type,"reiserfs",reiserfs_read_super);

//
// this is exactly what 2.3.99-pre9's init_ext2_fs is
//
static int __init init_reiserfs_fs (void)
{
	reiserfs_proc_info_global_init();
	reiserfs_proc_register_global( "version", 
				       reiserfs_global_version_in_proc );
        return register_filesystem(&reiserfs_fs_type);
}

MODULE_DESCRIPTION("ReiserFS journaled filesystem");
MODULE_AUTHOR("Hans Reiser <[e-mail]>");
MODULE_LICENSE("GPL");
EXPORT_NO_SYMBOLS;

//
// this is exactly what 2.3.99-pre9's init_ext2_fs is
//
static void __exit exit_reiserfs_fs(void)
{
	reiserfs_proc_unregister_global( "version" );
	reiserfs_proc_info_global_done();
        unregister_filesystem(&reiserfs_fs_type);
}


module_init(init_reiserfs_fs) ;
module_exit(exit_reiserfs_fs) ;