/* k1 is pointer to on-disk structure which is stored in little-endian
   form. k2 is pointer to cpu variable.
   Compare keys using all 4 key fields.
   Returns: -1 if key1 < key2 0
   if key1 = key2 1 if key1 > key2 */
static inline int comp_keys(const struct reiserfs_key *le_key,
			    const struct cpu_key *cpu_key)
{
	int retval;

	retval = comp_short_keys(le_key, cpu_key);
	if (retval)
		return retval;
	if (le_key_k_offset(le_key_version(le_key), le_key) <
	    cpu_key_k_offset(cpu_key))
		return -1;
	if (le_key_k_offset(le_key_version(le_key), le_key) >
	    cpu_key_k_offset(cpu_key))
		return 1;

	if (cpu_key->key_length == 3)
		return 0;

	/* this part is needed only when tail conversion is in progress */
	if (le_key_k_type(le_key_version(le_key), le_key) <
	    cpu_key_k_type(cpu_key))
		return -1;

	if (le_key_k_type(le_key_version(le_key), le_key) >
	    cpu_key_k_type(cpu_key))
		return 1;

	return 0;
}

/*
 * k1 is pointer to on-disk structure which is stored in little-endian
 * form. k2 is pointer to cpu variable. Compare keys using all 4 key
 * fields.
 * Returns: -1 if key1 < key2, 0 if key1 = key2 or 1 if key1 > key2
 */
/*inline*/ int
comp_keys(const struct key *le_key, const struct cpu_key *cpu_key)
{
	int retval;

	retval = comp_short_keys(le_key, cpu_key);
	if (retval)
		return retval;

	if (le_key_k_offset(le_key_version(le_key), le_key) <
	    cpu_key_k_offset(cpu_key))
		return (-1);
	if (le_key_k_offset(le_key_version(le_key), le_key) >
	    cpu_key_k_offset(cpu_key))
		return (1);

	if (cpu_key->key_length == 3)
		return (0);

	/* This part is needed only when tail conversion is in progress */
	if (le_key_k_type(le_key_version(le_key), le_key) < 
	    cpu_key_k_type(cpu_key))
		return (-1);

	if (le_key_k_type(le_key_version(le_key), le_key) >
	    cpu_key_k_type(cpu_key))
		return (1);

	return (0);
}

static char * reiserfs_cpu_offset (struct cpu_key * key)
{
  if (cpu_key_k_type(key) == TYPE_DIRENTRY)
    sprintf (off_buf, "%Lu(%Lu)", 
	     (unsigned long long)GET_HASH_VALUE (cpu_key_k_offset (key)),
	     (unsigned long long)GET_GENERATION_NUMBER (cpu_key_k_offset (key)));
  else
    sprintf (off_buf, "0x%Lx", (unsigned long long)cpu_key_k_offset (key));
  return off_buf;
}

/* The function is NOT SCHEDULE-SAFE! */
int search_by_entry_key(struct super_block *sb, const struct cpu_key *key,
			struct treepath *path, struct reiserfs_dir_entry *de)
{
	int retval;

	retval = search_item(sb, key, path);
	switch (retval) {
	case ITEM_NOT_FOUND:
		if (!PATH_LAST_POSITION(path)) {
			reiserfs_error(sb, "vs-7000", "search_by_key "
				       "returned item position == 0");
			pathrelse(path);
			return IO_ERROR;
		}
		PATH_LAST_POSITION(path)--;

	case ITEM_FOUND:
		break;

	case IO_ERROR:
		return retval;

	default:
		pathrelse(path);
		reiserfs_error(sb, "vs-7002", "no path to here");
		return IO_ERROR;
	}

	set_de_item_location(de, path);

#ifdef CONFIG_REISERFS_CHECK
	if (!is_direntry_le_ih(de->de_ih) ||
	    COMP_SHORT_KEYS(&de->de_ih->ih_key, key)) {
		print_block(de->de_bh, 0, -1, -1);
		reiserfs_panic(sb, "vs-7005", "found item %h is not directory "
			       "item or does not belong to the same directory "
			       "as key %K", de->de_ih, key);
	}
#endif				/* CONFIG_REISERFS_CHECK */

	/*
	 * binary search in directory item by third component of the
	 * key. sets de->de_entry_num of de
	 */
	retval = bin_search_in_dir_item(de, cpu_key_k_offset(key));
	path->pos_in_item = de->de_entry_num;
	if (retval != NAME_NOT_FOUND) {
		/*
		 * ugly, but rename needs de_bh, de_deh, de_name,
		 * de_namelen, de_objectid set
		 */
		set_de_name_and_namelen(de);
		set_de_object_key(de);
	}
	return retval;
}

/*
 * We assign a key to each directory item, and place multiple entries in
 * a single directory item. A directory item has a key equal to the key
 * of the first directory entry in it.
 *
 * This function first calls search_by_key, then, if item whose first
 * entry matches is not found it looks for the entry inside directory
 * item found by search_by_key. Fills the path to the entry, and to the
 * entry position in the item
 */
int
search_by_entry_key(struct reiserfs_sb_info *sbi,
    const struct cpu_key *key, struct path *path,
    struct reiserfs_dir_entry *de)
{
	int retval;

	reiserfs_log(LOG_DEBUG, "searching in (objectid=%d,dirid=%d)\n",
	    key->on_disk_key.k_objectid, key->on_disk_key.k_dir_id);
	retval = search_item(sbi, key, path);
	switch (retval) {
	case ITEM_NOT_FOUND:
		if (!PATH_LAST_POSITION(path)) {
			reiserfs_log(LOG_DEBUG,
			    "search_by_key returned item position == 0");
			pathrelse(path);
			return (IO_ERROR);
		}
		PATH_LAST_POSITION(path)--;
		reiserfs_log(LOG_DEBUG, "search_by_key did not found it\n");
		break;
	case ITEM_FOUND:
		reiserfs_log(LOG_DEBUG, "search_by_key found it\n");
		break;
	case IO_ERROR:
		return (retval);
	default:
		pathrelse(path);
		reiserfs_log(LOG_DEBUG, "no path to here");
		return (IO_ERROR);
	}

	reiserfs_log(LOG_DEBUG, "set item location\n");
	set_de_item_location(de, path);

	/*
	 * Binary search in directory item by third component of the
	 * key. Sets de->de_entry_num of de
	 */
	reiserfs_log(LOG_DEBUG, "bin_search_in_dir_item\n");
	retval = bin_search_in_dir_item(de, cpu_key_k_offset(key));
	path->pos_in_item = de->de_entry_num;
	if (retval != NAME_NOT_FOUND) {
		/*
		 * Ugly, but rename needs de_bp, de_deh, de_name, de_namelen,
		 * de_objectid set
		 */
		set_de_name_and_namelen(de);
		set_de_object_key(de);
		reiserfs_log(LOG_DEBUG, "set (objectid=%d,dirid=%d)\n",
		    de->de_objectid, de->de_dir_id);
	}

	return (retval);
}

static int reiserfs_readdir (struct file * filp, void * dirent, filldir_t filldir)
{
    struct inode *inode = filp->f_dentry->d_inode;
    struct cpu_key pos_key;	/* key of current position in the directory (key of directory entry) */
    INITIALIZE_PATH (path_to_entry);
    struct buffer_head * bh;
    int item_num, entry_num;
    const struct key * rkey;
    struct item_head * ih, tmp_ih;
    int search_res;
    char * local_buf;
    loff_t next_pos;
    char small_buf[32] ; /* avoid kmalloc if we can */
    struct reiserfs_dir_entry de;


    reiserfs_check_lock_depth("readdir") ;

    /* form key for search the next directory entry using f_pos field of
       file structure */
    make_cpu_key (&pos_key, inode, (filp->f_pos) ? (filp->f_pos) : DOT_OFFSET,
		  TYPE_DIRENTRY, 3);
    next_pos = cpu_key_k_offset (&pos_key);

    /*  reiserfs_warning ("reiserfs_readdir 1: f_pos = %Ld\n", filp->f_pos);*/

    while (1) {
    research:
	/* search the directory item, containing entry with specified key */
	search_res = search_by_entry_key (inode->i_sb, &pos_key, &path_to_entry, &de);
	if (search_res == IO_ERROR) {
	    // FIXME: we could just skip part of directory which could
	    // not be read
	    return -EIO;
	}
	entry_num = de.de_entry_num;
	bh = de.de_bh;
	item_num = de.de_item_num;
	ih = de.de_ih;
	store_ih (&tmp_ih, ih);
		
	/* we must have found item, that is item of this directory, */
	RFALSE( COMP_SHORT_KEYS (&(ih->ih_key), &pos_key),
		"vs-9000: found item %h does not match to dir we readdir %K",
		ih, &pos_key);
	RFALSE( item_num > B_NR_ITEMS (bh) - 1,
		"vs-9005 item_num == %d, item amount == %d", 
		item_num, B_NR_ITEMS (bh));
      
	/* and entry must be not more than number of entries in the item */
	RFALSE( I_ENTRY_COUNT (ih) < entry_num,
		"vs-9010: entry number is too big %d (%d)", 
		entry_num, I_ENTRY_COUNT (ih));

	if (search_res == POSITION_FOUND || entry_num < I_ENTRY_COUNT (ih)) {
	    /* go through all entries in the directory item beginning from the entry, that has been found */
	    struct reiserfs_de_head * deh = B_I_DEH (bh, ih) + entry_num;

	    for (; entry_num < I_ENTRY_COUNT (ih); entry_num ++, deh ++) {
		int d_reclen;
		char * d_name;
		off_t d_off;
		ino_t d_ino;

		if (!de_visible (deh))
		    /* it is hidden entry */
		    continue;
		d_reclen = entry_length (bh, ih, entry_num);
		d_name = B_I_DEH_ENTRY_FILE_NAME (bh, ih, deh);
		if (!d_name[d_reclen - 1])
		    d_reclen = strlen (d_name);
	
		if (d_reclen > REISERFS_MAX_NAME_LEN(inode->i_sb->s_blocksize)){
		    /* too big to send back to VFS */
		    continue ;
		}
		d_off = deh_offset (deh);
		filp->f_pos = d_off ;
		d_ino = deh_objectid (deh);
		if (d_reclen <= 32) {
		  local_buf = small_buf ;
		} else {
		    local_buf = reiserfs_kmalloc(d_reclen, GFP_NOFS, inode->i_sb) ;
		    if (!local_buf) {
			pathrelse (&path_to_entry);
			return -ENOMEM ;
		    }
		    if (item_moved (&tmp_ih, &path_to_entry)) {
			reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ;
			goto research;
		    }
		}
		// Note, that we copy name to user space via temporary
		// buffer (local_buf) because filldir will block if
		// user space buffer is swapped out. At that time
		// entry can move to somewhere else
		memcpy (local_buf, d_name, d_reclen);
		if (filldir (dirent, local_buf, d_reclen, d_off, d_ino, 
		             DT_UNKNOWN) < 0) {
		    if (local_buf != small_buf) {
//.........这里部分代码省略.........

/* The function is NOT SCHEDULE-SAFE! */
int
search_for_position_by_key(struct reiserfs_sb_info *p_s_sbi,
    const struct cpu_key *p_cpu_key, /* Key to search (cpu variable) */
    struct path *p_s_search_path)    /* Filled up by this function.  */
{
	int retval, n_blk_size;
	off_t item_offset, offset;
	struct item_head *p_le_ih; /* Pointer to on-disk structure */
	struct reiserfs_dir_entry de;

	/* If searching for directory entry. */
	if (is_direntry_cpu_key(p_cpu_key))
		return (search_by_entry_key(p_s_sbi, p_cpu_key,
		    p_s_search_path, &de));

	/* If not searching for directory entry. */

	/* If item is found. */
	retval = search_item(p_s_sbi, p_cpu_key, p_s_search_path);
	if (retval == IO_ERROR)
		return (retval);
	if (retval == ITEM_FOUND) {
		if (ih_item_len(B_N_PITEM_HEAD(
		    PATH_PLAST_BUFFER(p_s_search_path),
		    PATH_LAST_POSITION(p_s_search_path))) == 0) {
			reiserfs_log(LOG_WARNING, "item length equals zero\n");
		}

		pos_in_item(p_s_search_path) = 0;
		return (POSITION_FOUND);
	}

	if (PATH_LAST_POSITION(p_s_search_path) == 0) {
		reiserfs_log(LOG_WARNING, "position equals zero\n");
	}

	/* Item is not found. Set path to the previous item. */
	p_le_ih = B_N_PITEM_HEAD(PATH_PLAST_BUFFER(p_s_search_path),
	    --PATH_LAST_POSITION(p_s_search_path));
	n_blk_size = p_s_sbi->s_blocksize;

	if (comp_short_keys(&(p_le_ih->ih_key), p_cpu_key)) {
		return (FILE_NOT_FOUND);
	}

	item_offset = le_ih_k_offset(p_le_ih);
	offset = cpu_key_k_offset(p_cpu_key);

	/* Needed byte is contained in the item pointed to by the path.*/
	if (item_offset <= offset &&
	    item_offset + op_bytes_number(p_le_ih, n_blk_size) > offset) {
		pos_in_item(p_s_search_path) = offset - item_offset;
		if (is_indirect_le_ih(p_le_ih)) {
			pos_in_item(p_s_search_path) /= n_blk_size;
		}
		return (POSITION_FOUND);
	}

	/* Needed byte is not contained in the item pointed to by the
	 * path. Set pos_in_item out of the item. */
	if (is_indirect_le_ih(p_le_ih))
		pos_in_item(p_s_search_path) =
		    ih_item_len(p_le_ih) / UNFM_P_SIZE;
	else
		pos_in_item(p_s_search_path) =
		    ih_item_len(p_le_ih);

	return (POSITION_NOT_FOUND);
}

static int reiserfs_add_entry(struct reiserfs_transaction_handle *th,
			      struct inode *dir, const char *name, int namelen,
			      struct inode *inode, int visible)
{
	struct cpu_key entry_key;
	struct reiserfs_de_head *deh;
	INITIALIZE_PATH(path);
	struct reiserfs_dir_entry de;
	DECLARE_BITMAP(bit_string, MAX_GENERATION_NUMBER + 1);
	int gen_number;
	char small_buf[32 + DEH_SIZE];	/* 48 bytes now and we avoid kmalloc
					   if we create file with short name */
	char *buffer;
	int buflen, paste_size;
	int retval;

	BUG_ON(!th->t_trans_id);

	/* cannot allow items to be added into a busy deleted directory */
	if (!namelen)
		return -EINVAL;

	if (namelen > REISERFS_MAX_NAME(dir->i_sb->s_blocksize))
		return -ENAMETOOLONG;

	/* each entry has unique key. compose it */
	make_cpu_key(&entry_key, dir,
		     get_third_component(dir->i_sb, name, namelen),
		     TYPE_DIRENTRY, 3);

	/* get memory for composing the entry */
	buflen = DEH_SIZE + ROUND_UP(namelen);
	if (buflen > sizeof(small_buf)) {
		buffer = kmalloc(buflen, GFP_NOFS);
		if (!buffer)
			return -ENOMEM;
	} else
		buffer = small_buf;

	paste_size =
	    (get_inode_sd_version(dir) ==
	     STAT_DATA_V1) ? (DEH_SIZE + namelen) : buflen;

	/* fill buffer : directory entry head, name[, dir objectid | , stat data | ,stat data, dir objectid ] */
	deh = (struct reiserfs_de_head *)buffer;
	deh->deh_location = 0;	/* JDM Endian safe if 0 */
	put_deh_offset(deh, cpu_key_k_offset(&entry_key));
	deh->deh_state = 0;	/* JDM Endian safe if 0 */
	/* put key (ino analog) to de */
	deh->deh_dir_id = INODE_PKEY(inode)->k_dir_id;	/* safe: k_dir_id is le */
	deh->deh_objectid = INODE_PKEY(inode)->k_objectid;	/* safe: k_objectid is le */

	/* copy name */
	memcpy((char *)(deh + 1), name, namelen);
	/* padd by 0s to the 4 byte boundary */
	padd_item((char *)(deh + 1), ROUND_UP(namelen), namelen);

	/* entry is ready to be pasted into tree, set 'visibility' and 'stat data in entry' attributes */
	mark_de_without_sd(deh);
	visible ? mark_de_visible(deh) : mark_de_hidden(deh);

	/* find the proper place for the new entry */
	memset(bit_string, 0, sizeof(bit_string));
	de.de_gen_number_bit_string = bit_string;
	retval = reiserfs_find_entry(dir, name, namelen, &path, &de);
	if (retval != NAME_NOT_FOUND) {
		if (buffer != small_buf)
			kfree(buffer);
		pathrelse(&path);

		if (retval == IO_ERROR) {
			return -EIO;
		}

		if (retval != NAME_FOUND) {
			reiserfs_error(dir->i_sb, "zam-7002",
				       "reiserfs_find_entry() returned "
				       "unexpected value (%d)", retval);
		}

		return -EEXIST;
	}

	gen_number =
	    find_first_zero_bit(bit_string,
				MAX_GENERATION_NUMBER + 1);
	if (gen_number > MAX_GENERATION_NUMBER) {
		/* there is no free generation number */
		reiserfs_warning(dir->i_sb, "reiserfs-7010",
				 "Congratulations! we have got hash function "
				 "screwed up");
		if (buffer != small_buf)
			kfree(buffer);
		pathrelse(&path);
		return -EBUSY;
	}
	/* adjust offset of directory enrty */
	put_deh_offset(deh, SET_GENERATION_NUMBER(deh_offset(deh), gen_number));
	set_cpu_key_k_offset(&entry_key, deh_offset(deh));

//.........这里部分代码省略.........

static int linear_search_in_dir_item(struct cpu_key *key,
				     struct reiserfs_dir_entry *de,
				     const char *name, int namelen)
{
	struct reiserfs_de_head *deh = de->de_deh;
	int retval;
	int i;

	i = de->de_entry_num;

	if (i == I_ENTRY_COUNT(de->de_ih) ||
	    GET_HASH_VALUE(deh_offset(deh + i)) !=
	    GET_HASH_VALUE(cpu_key_k_offset(key))) {
		i--;
	}

	RFALSE(de->de_deh != B_I_DEH(de->de_bh, de->de_ih),
	       "vs-7010: array of entry headers not found");

	deh += i;

	for (; i >= 0; i--, deh--) {
		if (GET_HASH_VALUE(deh_offset(deh)) !=
		    GET_HASH_VALUE(cpu_key_k_offset(key))) {
			// hash value does not match, no need to check whole name
			return NAME_NOT_FOUND;
		}

		/* mark, that this generation number is used */
		if (de->de_gen_number_bit_string)
			set_bit(GET_GENERATION_NUMBER(deh_offset(deh)),
				de->de_gen_number_bit_string);

		// calculate pointer to name and namelen
		de->de_entry_num = i;
		set_de_name_and_namelen(de);

		if ((retval =
		     reiserfs_match(de, name, namelen)) != NAME_NOT_FOUND) {
			// de's de_name, de_namelen, de_recordlen are set. Fill the rest:

			// key of pointed object
			set_de_object_key(de);

			store_de_entry_key(de);

			// retval can be NAME_FOUND or NAME_FOUND_INVISIBLE
			return retval;
		}
	}

	if (GET_GENERATION_NUMBER(le_ih_k_offset(de->de_ih)) == 0)
		/* we have reached left most entry in the node. In common we
		   have to go to the left neighbor, but if generation counter
		   is 0 already, we know for sure, that there is no name with
		   the same hash value */
		// FIXME: this work correctly only because hash value can not
		// be 0. Btw, in case of Yura's hash it is probably possible,
		// so, this is a bug
		return NAME_NOT_FOUND;

	RFALSE(de->de_item_num,
	       "vs-7015: two diritems of the same directory in one node?");

	return GOTO_PREVIOUS_ITEM;
}

/*
 * de's de_bh, de_ih, de_deh, de_item_num, de_entry_num are set already
 * Used when hash collisions exist
 */
static int
linear_search_in_dir_item(struct cpu_key *key, struct reiserfs_dir_entry *de,
    const char *name, int namelen)
{
	int i;
	int retval;
	struct reiserfs_de_head * deh = de->de_deh;

	i = de->de_entry_num;

	if (i == I_ENTRY_COUNT(de->de_ih) ||
	    GET_HASH_VALUE(deh_offset(deh + i)) !=
	    GET_HASH_VALUE(cpu_key_k_offset(key))) {
		i--;
	}

	/*RFALSE( de->de_deh != B_I_DEH (de->de_bh, de->de_ih),
	  "vs-7010: array of entry headers not found");*/

	deh += i;

	for (; i >= 0; i--, deh--) {
		if (GET_HASH_VALUE(deh_offset(deh)) !=
		    GET_HASH_VALUE(cpu_key_k_offset(key))) {
			/*
			 * Hash value does not match, no need to check
			 * whole name
			 */
			reiserfs_log(LOG_DEBUG, "name `%s' not found\n", name);
			return (NAME_NOT_FOUND);
		}

		/* Mark that this generation number is used */
		if (de->de_gen_number_bit_string)
			set_bit(GET_GENERATION_NUMBER(deh_offset(deh)),
			    (unsigned long *)de->de_gen_number_bit_string);

		/* Calculate pointer to name and namelen */
		de->de_entry_num = i;
		set_de_name_and_namelen(de);

		if ((retval = reiserfs_match(de, name, namelen)) !=
		    NAME_NOT_FOUND) {
			/*
			 * de's de_name, de_namelen, de_recordlen are set.
			 * Fill the rest:
			 */
			/* key of pointed object */
			set_de_object_key(de);
			store_de_entry_key(de);

			/* retval can be NAME_FOUND or NAME_FOUND_INVISIBLE */
			reiserfs_log(LOG_DEBUG,
			    "reiserfs_match answered `%d'\n",
			    retval);
			return (retval);
		}
	}

	if (GET_GENERATION_NUMBER(le_ih_k_offset(de->de_ih)) == 0)
		/*
		 * We have reached left most entry in the node. In common
		 * we have to go to the left neighbor, but if generation
		 * counter is 0 already, we know for sure, that there is
		 * no name with the same hash value
		 */
		/* FIXME: this work correctly only because hash value can
		 * not be 0. Btw, in case of Yura's hash it is probably
		 * possible, so, this is a bug
		 */
		return (NAME_NOT_FOUND);

	/*RFALSE(de->de_item_num,
	    "vs-7015: two diritems of the same directory in one node?");*/

	return (GOTO_PREVIOUS_ITEM);
}

int
reiserfs_readdir(struct vop_readdir_args  /* {
		struct vnode *a_vp;
		struct uio *a_uio;
		struct ucred *a_cred;
		int *a_eofflag;
		int *a_ncookies;
		u_long **a_cookies;
	} */*ap)
{
	int error = 0;
	struct dirent dstdp;
	struct uio *uio = ap->a_uio;

	off_t next_pos;
	struct buf *bp;
	struct item_head *ih;
	struct cpu_key pos_key;
	const struct key *rkey;
	struct reiserfs_node *ip;
	struct reiserfs_dir_entry de;
	INITIALIZE_PATH(path_to_entry);
	int entry_num, item_num, search_res;

	/* The NFS part */
	int ncookies = 0;
	u_long *cookies = NULL;

	/*
	 * Form key for search the next directory entry using f_pos field of
	 * file structure
	 */
	ip = VTOI(ap->a_vp);
	make_cpu_key(&pos_key,
	    ip, uio->uio_offset ? uio->uio_offset : DOT_OFFSET,
	    TYPE_DIRENTRY, 3);
	next_pos = cpu_key_k_offset(&pos_key);

	reiserfs_log(LOG_DEBUG, "listing entries for "
	    "(objectid=%d, dirid=%d)\n",
	    pos_key.on_disk_key.k_objectid, pos_key.on_disk_key.k_dir_id);
	reiserfs_log(LOG_DEBUG, "uio_offset = %jd, uio_resid = %d\n",
	    (intmax_t)uio->uio_offset, uio->uio_resid);

	if (ap->a_ncookies && ap->a_cookies) {
		cookies = (u_long *)malloc(
		    uio->uio_resid / 16 * sizeof(u_long),
		    M_REISERFSCOOKIES, M_WAITOK);
	}

	while (1) {
		//research:
		/*
		 * Search the directory item, containing entry with
		 * specified key
		 */
		reiserfs_log(LOG_DEBUG, "search directory to read\n");
		search_res = search_by_entry_key(ip->i_reiserfs, &pos_key,
		    &path_to_entry, &de);
		if (search_res == IO_ERROR) {
			error = EIO;
			goto out;
		}

		entry_num = de.de_entry_num;
		item_num  = de.de_item_num;
		bp = de.de_bp;
		ih = de.de_ih;

		if (search_res == POSITION_FOUND ||
		    entry_num < I_ENTRY_COUNT(ih)) {
			/*
			 * Go through all entries in the directory item
			 * beginning from the entry, that has been found.
			 */
			struct reiserfs_de_head *deh = B_I_DEH(bp, ih) +
			    entry_num;

			if (ap->a_ncookies == NULL) {
				cookies = NULL;
			} else {
				//ncookies = 
			}

			reiserfs_log(LOG_DEBUG,
			    "walking through directory entries\n");
			for (; entry_num < I_ENTRY_COUNT(ih);
			    entry_num++, deh++) {
				int d_namlen;
				char *d_name;
				off_t d_off;
				ino_t d_ino;

				if (!de_visible(deh)) {
					/* It is hidden entry */
					continue;
				}

				d_namlen = entry_length(bp, ih, entry_num);
				d_name   = B_I_DEH_ENTRY_FILE_NAME(bp, ih, deh);
//.........这里部分代码省略.........

int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
			   filldir_t filldir, loff_t *pos)
{
	struct inode *inode = dentry->d_inode;
	struct cpu_key pos_key;	
	INITIALIZE_PATH(path_to_entry);
	struct buffer_head *bh;
	int item_num, entry_num;
	const struct reiserfs_key *rkey;
	struct item_head *ih, tmp_ih;
	int search_res;
	char *local_buf;
	loff_t next_pos;
	char small_buf[32];	
	struct reiserfs_dir_entry de;
	int ret = 0;

	reiserfs_write_lock(inode->i_sb);

	reiserfs_check_lock_depth(inode->i_sb, "readdir");

	make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
	next_pos = cpu_key_k_offset(&pos_key);

	path_to_entry.reada = PATH_READA;
	while (1) {
	      research:
		
		search_res =
		    search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
					&de);
		if (search_res == IO_ERROR) {
			
			
			ret = -EIO;
			goto out;
		}
		entry_num = de.de_entry_num;
		bh = de.de_bh;
		item_num = de.de_item_num;
		ih = de.de_ih;
		store_ih(&tmp_ih, ih);

		
		RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
		       "vs-9000: found item %h does not match to dir we readdir %K",
		       ih, &pos_key);
		RFALSE(item_num > B_NR_ITEMS(bh) - 1,
		       "vs-9005 item_num == %d, item amount == %d",
		       item_num, B_NR_ITEMS(bh));

		
		RFALSE(I_ENTRY_COUNT(ih) < entry_num,
		       "vs-9010: entry number is too big %d (%d)",
		       entry_num, I_ENTRY_COUNT(ih));

		if (search_res == POSITION_FOUND
		    || entry_num < I_ENTRY_COUNT(ih)) {
			
			struct reiserfs_de_head *deh =
			    B_I_DEH(bh, ih) + entry_num;

			for (; entry_num < I_ENTRY_COUNT(ih);
			     entry_num++, deh++) {
				int d_reclen;
				char *d_name;
				off_t d_off;
				ino_t d_ino;

				if (!de_visible(deh))
					
					continue;
				d_reclen = entry_length(bh, ih, entry_num);
				d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);

				if (d_reclen <= 0 ||
				    d_name + d_reclen > bh->b_data + bh->b_size) {
					pathrelse(&path_to_entry);
					ret = -EIO;
					goto out;
				}

				if (!d_name[d_reclen - 1])
					d_reclen = strlen(d_name);

				if (d_reclen >
				    REISERFS_MAX_NAME(inode->i_sb->
						      s_blocksize)) {
					
					continue;
				}

				
				if (is_privroot_deh(dentry, deh))
					continue;

				d_off = deh_offset(deh);
				*pos = d_off;
				d_ino = deh_objectid(deh);
				if (d_reclen <= 32) {
//.........这里部分代码省略.........

// decrease offset, if it becomes 0, change type to stat data
static void indirect_decrement_key(struct cpu_key *key)
{
	cpu_key_k_offset_dec(key);
	if (cpu_key_k_offset(key) == 0)
		set_cpu_key_k_type(key, TYPE_STAT_DATA);
}

int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
			   filldir_t filldir, loff_t *pos)
{
	struct inode *inode = dentry->d_inode;
	struct cpu_key pos_key;	/* key of current position in the directory (key of directory entry) */
	INITIALIZE_PATH(path_to_entry);
	struct buffer_head *bh;
	int item_num, entry_num;
	const struct reiserfs_key *rkey;
	struct item_head *ih, tmp_ih;
	int search_res;
	char *local_buf;
	loff_t next_pos;
	char small_buf[32];	/* avoid kmalloc if we can */
	struct reiserfs_dir_entry de;
	int ret = 0;

	reiserfs_write_lock(inode->i_sb);

	reiserfs_check_lock_depth(inode->i_sb, "readdir");

	/* form key for search the next directory entry using f_pos field of
	   file structure */
	make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
	next_pos = cpu_key_k_offset(&pos_key);

	path_to_entry.reada = PATH_READA;
	while (1) {
	      research:
		/* search the directory item, containing entry with specified key */
		search_res =
		    search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
					&de);
		if (search_res == IO_ERROR) {
			// FIXME: we could just skip part of directory which could
			// not be read
			ret = -EIO;
			goto out;
		}
		entry_num = de.de_entry_num;
		bh = de.de_bh;
		item_num = de.de_item_num;
		ih = de.de_ih;
		store_ih(&tmp_ih, ih);

		/* we must have found item, that is item of this directory, */
		RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
		       "vs-9000: found item %h does not match to dir we readdir %K",
		       ih, &pos_key);
		RFALSE(item_num > B_NR_ITEMS(bh) - 1,
		       "vs-9005 item_num == %d, item amount == %d",
		       item_num, B_NR_ITEMS(bh));

		/* and entry must be not more than number of entries in the item */
		RFALSE(I_ENTRY_COUNT(ih) < entry_num,
		       "vs-9010: entry number is too big %d (%d)",
		       entry_num, I_ENTRY_COUNT(ih));

		if (search_res == POSITION_FOUND
		    || entry_num < I_ENTRY_COUNT(ih)) {
			/* go through all entries in the directory item beginning from the entry, that has been found */
			struct reiserfs_de_head *deh =
			    B_I_DEH(bh, ih) + entry_num;

			for (; entry_num < I_ENTRY_COUNT(ih);
			     entry_num++, deh++) {
				int d_reclen;
				char *d_name;
				off_t d_off;
				ino_t d_ino;
				loff_t cur_pos = deh_offset(deh);

				if (!de_visible(deh))
					/* it is hidden entry */
					continue;
				d_reclen = entry_length(bh, ih, entry_num);
				d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);

				if (d_reclen <= 0 ||
				    d_name + d_reclen > bh->b_data + bh->b_size) {
					/* There is corrupted data in entry,
					 * We'd better stop here */
					pathrelse(&path_to_entry);
					ret = -EIO;
					goto out;
				}

				if (!d_name[d_reclen - 1])
					d_reclen = strlen(d_name);

				if (d_reclen >
				    REISERFS_MAX_NAME(inode->i_sb->
						      s_blocksize)) {
					/* too big to send back to VFS */
					continue;
				}

				/* Ignore the .reiserfs_priv entry */
				if (is_privroot_deh(dentry, deh))
					continue;
//.........这里部分代码省略.........