[net-next-2.6.git] / fs / ext3 / dir.c

/*
 *  linux/fs/ext3/dir.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/dir.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  ext3 directory handling functions
 *
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 *
 * Hash Tree Directory indexing (c) 2001  Daniel Phillips
 *
 */

#include <linux/fs.h>
#include <linux/jbd.h>
#include <linux/ext3_fs.h>
#include <linux/buffer_head.h>
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <linux/rbtree.h>

static unsigned char ext3_filetype_table[] = {
	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
};

static int ext3_readdir(struct file *, void *, filldir_t);
static int ext3_dx_readdir(struct file * filp,
			   void * dirent, filldir_t filldir);
static int ext3_release_dir (struct inode * inode,
				struct file * filp);

const struct file_operations ext3_dir_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_read_dir,
	.readdir	= ext3_readdir,		/* we take BKL. needed?*/
	.ioctl		= ext3_ioctl,		/* BKL held */
	.fsync		= ext3_sync_file,	/* BKL held */
#ifdef CONFIG_EXT3_INDEX
	.release	= ext3_release_dir,
#endif
};


static unsigned char get_dtype(struct super_block *sb, int filetype)
{
	if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE) ||
	    (filetype >= EXT3_FT_MAX))
		return DT_UNKNOWN;

	return (ext3_filetype_table[filetype]);
}
			       

int ext3_check_dir_entry (const char * function, struct inode * dir,
			  struct ext3_dir_entry_2 * de,
			  struct buffer_head * bh,
			  unsigned long offset)
{
	const char * error_msg = NULL;
 	const int rlen = le16_to_cpu(de->rec_len);

	if (rlen < EXT3_DIR_REC_LEN(1))
		error_msg = "rec_len is smaller than minimal";
	else if (rlen % 4 != 0)
		error_msg = "rec_len % 4 != 0";
	else if (rlen < EXT3_DIR_REC_LEN(de->name_len))
		error_msg = "rec_len is too small for name_len";
	else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
		error_msg = "directory entry across blocks";
	else if (le32_to_cpu(de->inode) >
			le32_to_cpu(EXT3_SB(dir->i_sb)->s_es->s_inodes_count))
		error_msg = "inode out of bounds";

	if (error_msg != NULL)
		ext3_error (dir->i_sb, function,
			"bad entry in directory #%lu: %s - "
			"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
			dir->i_ino, error_msg, offset,
			(unsigned long) le32_to_cpu(de->inode),
			rlen, de->name_len);
	return error_msg == NULL ? 1 : 0;
}

static int ext3_readdir(struct file * filp,
			 void * dirent, filldir_t filldir)
{
	int error = 0;
	unsigned long offset;
	int i, stored;
	struct ext3_dir_entry_2 *de;
	struct super_block *sb;
	int err;
	struct inode *inode = filp->f_dentry->d_inode;
	int ret = 0;

	sb = inode->i_sb;

#ifdef CONFIG_EXT3_INDEX
	if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
				    EXT3_FEATURE_COMPAT_DIR_INDEX) &&
	    ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
	     ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
		err = ext3_dx_readdir(filp, dirent, filldir);
		if (err != ERR_BAD_DX_DIR) {
			ret = err;
			goto out;
		}
		/*
		 * We don't set the inode dirty flag since it's not
		 * critical that it get flushed back to the disk.
		 */
		EXT3_I(filp->f_dentry->d_inode)->i_flags &= ~EXT3_INDEX_FL;
	}
#endif
	stored = 0;
	offset = filp->f_pos & (sb->s_blocksize - 1);

	while (!error && !stored && filp->f_pos < inode->i_size) {
		unsigned long blk = filp->f_pos >> EXT3_BLOCK_SIZE_BITS(sb);
		struct buffer_head map_bh;
		struct buffer_head *bh = NULL;

		map_bh.b_state = 0;
		err = ext3_get_blocks_handle(NULL, inode, blk, 1,
						&map_bh, 0, 0);
		if (err > 0) {
			page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
				&filp->f_ra,
				filp,
				map_bh.b_blocknr >>
					(PAGE_CACHE_SHIFT - inode->i_blkbits),
				1);
			bh = ext3_bread(NULL, inode, blk, 0, &err);
		}

		/*
		 * We ignore I/O errors on directories so users have a chance
		 * of recovering data when there's a bad sector
		 */
		if (!bh) {
			ext3_error (sb, "ext3_readdir",
				"directory #%lu contains a hole at offset %lu",
				inode->i_ino, (unsigned long)filp->f_pos);
			filp->f_pos += sb->s_blocksize - offset;
			continue;
		}

revalidate:
		/* If the dir block has changed since the last call to
		 * readdir(2), then we might be pointing to an invalid
		 * dirent right now.  Scan from the start of the block
		 * to make sure. */
		if (filp->f_version != inode->i_version) {
			for (i = 0; i < sb->s_blocksize && i < offset; ) {
				de = (struct ext3_dir_entry_2 *) 
					(bh->b_data + i);
				/* It's too expensive to do a full
				 * dirent test each time round this
				 * loop, but we do have to test at
				 * least that it is non-zero.  A
				 * failure will be detected in the
				 * dirent test below. */
				if (le16_to_cpu(de->rec_len) <
						EXT3_DIR_REC_LEN(1))
					break;
				i += le16_to_cpu(de->rec_len);
			}
			offset = i;
			filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
				| offset;
			filp->f_version = inode->i_version;
		}

		while (!error && filp->f_pos < inode->i_size 
		       && offset < sb->s_blocksize) {
			de = (struct ext3_dir_entry_2 *) (bh->b_data + offset);
			if (!ext3_check_dir_entry ("ext3_readdir", inode, de,
						   bh, offset)) {
				/* On error, skip the f_pos to the
                                   next block. */
				filp->f_pos = (filp->f_pos |
						(sb->s_blocksize - 1)) + 1;
				brelse (bh);
				ret = stored;
				goto out;
			}
			offset += le16_to_cpu(de->rec_len);
			if (le32_to_cpu(de->inode)) {
				/* We might block in the next section
				 * if the data destination is
				 * currently swapped out.  So, use a
				 * version stamp to detect whether or
				 * not the directory has been modified
				 * during the copy operation.
				 */
				unsigned long version = filp->f_version;

				error = filldir(dirent, de->name,
						de->name_len,
						filp->f_pos,
						le32_to_cpu(de->inode),
						get_dtype(sb, de->file_type));
				if (error)
					break;
				if (version != filp->f_version)
					goto revalidate;
				stored ++;
			}
			filp->f_pos += le16_to_cpu(de->rec_len);
		}
		offset = 0;
		brelse (bh);
	}
out:
	return ret;
}

#ifdef CONFIG_EXT3_INDEX
/*
 * These functions convert from the major/minor hash to an f_pos
 * value.
 * 
 * Currently we only use major hash numer.  This is unfortunate, but
 * on 32-bit machines, the same VFS interface is used for lseek and
 * llseek, so if we use the 64 bit offset, then the 32-bit versions of
 * lseek/telldir/seekdir will blow out spectacularly, and from within
 * the ext2 low-level routine, we don't know if we're being called by
 * a 64-bit version of the system call or the 32-bit version of the
 * system call.  Worse yet, NFSv2 only allows for a 32-bit readdir
 * cookie.  Sigh.
 */
#define hash2pos(major, minor)	(major >> 1)
#define pos2maj_hash(pos)	((pos << 1) & 0xffffffff)
#define pos2min_hash(pos)	(0)

/*
 * This structure holds the nodes of the red-black tree used to store
 * the directory entry in hash order.
 */
struct fname {
	__u32		hash;
	__u32		minor_hash;
	struct rb_node	rb_hash; 
	struct fname	*next;
	__u32		inode;
	__u8		name_len;
	__u8		file_type;
	char		name[0];
};

/*
 * This functoin implements a non-recursive way of freeing all of the
 * nodes in the red-black tree.
 */
static void free_rb_tree_fname(struct rb_root *root)
{
	struct rb_node	*n = root->rb_node;
	struct rb_node	*parent;
	struct fname	*fname;

	while (n) {
		/* Do the node's children first */
		if ((n)->rb_left) {
			n = n->rb_left;
			continue;
		}
		if (n->rb_right) {
			n = n->rb_right;
			continue;
		}
		/*
		 * The node has no children; free it, and then zero
		 * out parent's link to it.  Finally go to the
		 * beginning of the loop and try to free the parent
		 * node.
		 */
		parent = rb_parent(n);
		fname = rb_entry(n, struct fname, rb_hash);
		while (fname) {
			struct fname * old = fname;
			fname = fname->next;
			kfree (old);
		}
		if (!parent)
			root->rb_node = NULL;
		else if (parent->rb_left == n)
			parent->rb_left = NULL;
		else if (parent->rb_right == n)
			parent->rb_right = NULL;
		n = parent;
	}
	root->rb_node = NULL;
}


static struct dir_private_info *create_dir_info(loff_t pos)
{
	struct dir_private_info *p;

	p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL);
	if (!p)
		return NULL;
	p->root.rb_node = NULL;
	p->curr_node = NULL;
	p->extra_fname = NULL;
	p->last_pos = 0;
	p->curr_hash = pos2maj_hash(pos);
	p->curr_minor_hash = pos2min_hash(pos);
	p->next_hash = 0;
	return p;
}

void ext3_htree_free_dir_info(struct dir_private_info *p)
{
	free_rb_tree_fname(&p->root);
	kfree(p);
}

/*
 * Given a directory entry, enter it into the fname rb tree.
 */
int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
			     __u32 minor_hash,
			     struct ext3_dir_entry_2 *dirent)
{
	struct rb_node **p, *parent = NULL;
	struct fname * fname, *new_fn;
	struct dir_private_info *info;
	int len;

	info = (struct dir_private_info *) dir_file->private_data;
	p = &info->root.rb_node;

	/* Create and allocate the fname structure */
	len = sizeof(struct fname) + dirent->name_len + 1;
	new_fn = kmalloc(len, GFP_KERNEL);
	if (!new_fn)
		return -ENOMEM;
	memset(new_fn, 0, len);
	new_fn->hash = hash;
	new_fn->minor_hash = minor_hash;
	new_fn->inode = le32_to_cpu(dirent->inode);
	new_fn->name_len = dirent->name_len;
	new_fn->file_type = dirent->file_type;
	memcpy(new_fn->name, dirent->name, dirent->name_len);
	new_fn->name[dirent->name_len] = 0;

	while (*p) {
		parent = *p;
		fname = rb_entry(parent, struct fname, rb_hash);

		/*
		 * If the hash and minor hash match up, then we put
		 * them on a linked list.  This rarely happens...
		 */
		if ((new_fn->hash == fname->hash) &&
		    (new_fn->minor_hash == fname->minor_hash)) {
			new_fn->next = fname->next;
			fname->next = new_fn;
			return 0;
		}

		if (new_fn->hash < fname->hash)
			p = &(*p)->rb_left;
		else if (new_fn->hash > fname->hash)
			p = &(*p)->rb_right;
		else if (new_fn->minor_hash < fname->minor_hash)
			p = &(*p)->rb_left;
		else /* if (new_fn->minor_hash > fname->minor_hash) */
			p = &(*p)->rb_right;
	}

	rb_link_node(&new_fn->rb_hash, parent, p);
	rb_insert_color(&new_fn->rb_hash, &info->root);
	return 0;
}


/*
 * This is a helper function for ext3_dx_readdir.  It calls filldir
 * for all entres on the fname linked list.  (Normally there is only
 * one entry on the linked list, unless there are 62 bit hash collisions.)
 */
static int call_filldir(struct file * filp, void * dirent,
			filldir_t filldir, struct fname *fname)
{
	struct dir_private_info *info = filp->private_data;
	loff_t	curr_pos;
	struct inode *inode = filp->f_dentry->d_inode;
	struct super_block * sb;
	int error;

	sb = inode->i_sb;

	if (!fname) {
		printk("call_filldir: called with null fname?!?\n");
		return 0;
	}
	curr_pos = hash2pos(fname->hash, fname->minor_hash);
	while (fname) {
		error = filldir(dirent, fname->name,
				fname->name_len, curr_pos, 
				fname->inode,
				get_dtype(sb, fname->file_type));
		if (error) {
			filp->f_pos = curr_pos;
			info->extra_fname = fname->next;
			return error;
		}
		fname = fname->next;
	}
	return 0;
}

static int ext3_dx_readdir(struct file * filp,
			 void * dirent, filldir_t filldir)
{
	struct dir_private_info *info = filp->private_data;
	struct inode *inode = filp->f_dentry->d_inode;
	struct fname *fname;
	int	ret;

	if (!info) {
		info = create_dir_info(filp->f_pos);
		if (!info)
			return -ENOMEM;
		filp->private_data = info;
	}

	if (filp->f_pos == EXT3_HTREE_EOF)
		return 0;	/* EOF */

	/* Some one has messed with f_pos; reset the world */
	if (info->last_pos != filp->f_pos) {
		free_rb_tree_fname(&info->root);
		info->curr_node = NULL;
		info->extra_fname = NULL;
		info->curr_hash = pos2maj_hash(filp->f_pos);
		info->curr_minor_hash = pos2min_hash(filp->f_pos);
	}

	/*
	 * If there are any leftover names on the hash collision
	 * chain, return them first.
	 */
	if (info->extra_fname &&
	    call_filldir(filp, dirent, filldir, info->extra_fname))
		goto finished;

	if (!info->curr_node)
		info->curr_node = rb_first(&info->root);

	while (1) {
		/*
		 * Fill the rbtree if we have no more entries,
		 * or the inode has changed since we last read in the
		 * cached entries. 
		 */
		if ((!info->curr_node) ||
		    (filp->f_version != inode->i_version)) {
			info->curr_node = NULL;
			free_rb_tree_fname(&info->root);
			filp->f_version = inode->i_version;
			ret = ext3_htree_fill_tree(filp, info->curr_hash,
						   info->curr_minor_hash,
						   &info->next_hash);
			if (ret < 0)
				return ret;
			if (ret == 0) {
				filp->f_pos = EXT3_HTREE_EOF;
				break;
			}
			info->curr_node = rb_first(&info->root);
		}

		fname = rb_entry(info->curr_node, struct fname, rb_hash);
		info->curr_hash = fname->hash;
		info->curr_minor_hash = fname->minor_hash;
		if (call_filldir(filp, dirent, filldir, fname))
			break;

		info->curr_node = rb_next(info->curr_node);
		if (!info->curr_node) {
			if (info->next_hash == ~0) {
				filp->f_pos = EXT3_HTREE_EOF;
				break;
			}
			info->curr_hash = info->next_hash;
			info->curr_minor_hash = 0;
		}
	}
finished:
	info->last_pos = filp->f_pos;
	return 0;
}

static int ext3_release_dir (struct inode * inode, struct file * filp)
{
       if (filp->private_data)
		ext3_htree_free_dir_info(filp->private_data);

	return 0;
}

#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext3/dir.c
	3	*
	4	* Copyright (C) 1992, 1993, 1994, 1995
	5	* Remy Card (card@masi.ibp.fr)
	6	* Laboratoire MASI - Institut Blaise Pascal
	7	* Universite Pierre et Marie Curie (Paris VI)
	8	*
	9	* from
	10	*
	11	* linux/fs/minix/dir.c
	12	*
	13	* Copyright (C) 1991, 1992 Linus Torvalds
	14	*
	15	* ext3 directory handling functions
	16	*
	17	* Big-endian to little-endian byte-swapping/bitmaps by
	18	* David S. Miller (davem@caip.rutgers.edu), 1995
	19	*
	20	* Hash Tree Directory indexing (c) 2001 Daniel Phillips
	21	*
	22	*/
	23
	24	#include <linux/fs.h>
	25	#include <linux/jbd.h>
	26	#include <linux/ext3_fs.h>
	27	#include <linux/buffer_head.h>
	28	#include <linux/smp_lock.h>
	29	#include <linux/slab.h>
	30	#include <linux/rbtree.h>
	31
	32	static unsigned char ext3_filetype_table[] = {
	33	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
	34	};
	35
	36	static int ext3_readdir(struct file , void , filldir_t);
	37	static int ext3_dx_readdir(struct file * filp,
	38	void * dirent, filldir_t filldir);
	39	static int ext3_release_dir (struct inode * inode,
	40	struct file * filp);
	41
4b6f5d20	42	const struct file_operations ext3_dir_operations = {
1da177e4 LT	43	.llseek = generic_file_llseek,
	44	.read = generic_read_dir,
	45	.readdir = ext3_readdir, /* we take BKL. needed?*/
	46	.ioctl = ext3_ioctl, /* BKL held */
	47	.fsync = ext3_sync_file, /* BKL held */
	48	#ifdef CONFIG_EXT3_INDEX
	49	.release = ext3_release_dir,
	50	#endif
	51	};
	52
	53
	54	static unsigned char get_dtype(struct super_block *sb, int filetype)
	55	{
	56	if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE) \|\|
	57	(filetype >= EXT3_FT_MAX))
	58	return DT_UNKNOWN;
	59
	60	return (ext3_filetype_table[filetype]);
	61	}
	62
	63
	64	int ext3_check_dir_entry (const char * function, struct inode * dir,
	65	struct ext3_dir_entry_2 * de,
	66	struct buffer_head * bh,
	67	unsigned long offset)
	68	{
	69	const char * error_msg = NULL;
	70	const int rlen = le16_to_cpu(de->rec_len);
	71
	72	if (rlen < EXT3_DIR_REC_LEN(1))
	73	error_msg = "rec_len is smaller than minimal";
	74	else if (rlen % 4 != 0)
	75	error_msg = "rec_len % 4 != 0";
	76	else if (rlen < EXT3_DIR_REC_LEN(de->name_len))
	77	error_msg = "rec_len is too small for name_len";
	78	else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
	79	error_msg = "directory entry across blocks";
	80	else if (le32_to_cpu(de->inode) >
	81	le32_to_cpu(EXT3_SB(dir->i_sb)->s_es->s_inodes_count))
	82	error_msg = "inode out of bounds";
	83
	84	if (error_msg != NULL)
	85	ext3_error (dir->i_sb, function,
	86	"bad entry in directory #%lu: %s - "
	87	"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
	88	dir->i_ino, error_msg, offset,
	89	(unsigned long) le32_to_cpu(de->inode),
	90	rlen, de->name_len);
	91	return error_msg == NULL ? 1 : 0;
	92	}
	93
	94	static int ext3_readdir(struct file * filp,
	95	void * dirent, filldir_t filldir)
	96	{
	97	int error = 0;
d8733c29 AM	98	unsigned long offset;
	99	int i, stored;
	100	struct ext3_dir_entry_2 *de;
	101	struct super_block *sb;
1da177e4 LT	102	int err;
	103	struct inode *inode = filp->f_dentry->d_inode;
	104	int ret = 0;
	105
	106	sb = inode->i_sb;
	107
	108	#ifdef CONFIG_EXT3_INDEX
	109	if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
	110	EXT3_FEATURE_COMPAT_DIR_INDEX) &&
	111	((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) \|\|
	112	((inode->i_size >> sb->s_blocksize_bits) == 1))) {
	113	err = ext3_dx_readdir(filp, dirent, filldir);
	114	if (err != ERR_BAD_DX_DIR) {
	115	ret = err;
	116	goto out;
	117	}
	118	/*
	119	* We don't set the inode dirty flag since it's not
	120	* critical that it get flushed back to the disk.
	121	*/
	122	EXT3_I(filp->f_dentry->d_inode)->i_flags &= ~EXT3_INDEX_FL;
	123	}
	124	#endif
	125	stored = 0;
1da177e4 LT	126	offset = filp->f_pos & (sb->s_blocksize - 1);
	127
	128	while (!error && !stored && filp->f_pos < inode->i_size) {
d8733c29 AM	129	unsigned long blk = filp->f_pos >> EXT3_BLOCK_SIZE_BITS(sb);
	130	struct buffer_head map_bh;
	131	struct buffer_head *bh = NULL;
	132
	133	map_bh.b_state = 0;
89747d36 MC	134	err = ext3_get_blocks_handle(NULL, inode, blk, 1,
	135	&map_bh, 0, 0);
	136	if (err > 0) {
d8733c29 AM	137	page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
	138	&filp->f_ra,
	139	filp,
	140	map_bh.b_blocknr >>
	141	(PAGE_CACHE_SHIFT - inode->i_blkbits),
	142	1);
	143	bh = ext3_bread(NULL, inode, blk, 0, &err);
	144	}
	145
	146	/*
	147	* We ignore I/O errors on directories so users have a chance
	148	* of recovering data when there's a bad sector
	149	*/
1da177e4 LT	150	if (!bh) {
	151	ext3_error (sb, "ext3_readdir",
	152	"directory #%lu contains a hole at offset %lu",
	153	inode->i_ino, (unsigned long)filp->f_pos);
	154	filp->f_pos += sb->s_blocksize - offset;
	155	continue;
	156	}
	157
1da177e4 LT	158	revalidate:
	159	/* If the dir block has changed since the last call to
	160	* readdir(2), then we might be pointing to an invalid
	161	* dirent right now. Scan from the start of the block
	162	* to make sure. */
	163	if (filp->f_version != inode->i_version) {
	164	for (i = 0; i < sb->s_blocksize && i < offset; ) {
	165	de = (struct ext3_dir_entry_2 *)
	166	(bh->b_data + i);
	167	/* It's too expensive to do a full
	168	* dirent test each time round this
	169	* loop, but we do have to test at
	170	* least that it is non-zero. A
	171	* failure will be detected in the
	172	* dirent test below. */
	173	if (le16_to_cpu(de->rec_len) <
	174	EXT3_DIR_REC_LEN(1))
	175	break;
	176	i += le16_to_cpu(de->rec_len);
	177	}
	178	offset = i;
	179	filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
	180	\| offset;
	181	filp->f_version = inode->i_version;
	182	}
	183
	184	while (!error && filp->f_pos < inode->i_size
	185	&& offset < sb->s_blocksize) {
	186	de = (struct ext3_dir_entry_2 *) (bh->b_data + offset);
	187	if (!ext3_check_dir_entry ("ext3_readdir", inode, de,
	188	bh, offset)) {
	189	/* On error, skip the f_pos to the
	190	next block. */
	191	filp->f_pos = (filp->f_pos \|
	192	(sb->s_blocksize - 1)) + 1;
	193	brelse (bh);
	194	ret = stored;
	195	goto out;
	196	}
	197	offset += le16_to_cpu(de->rec_len);
	198	if (le32_to_cpu(de->inode)) {
	199	/* We might block in the next section
	200	* if the data destination is
	201	* currently swapped out. So, use a
	202	* version stamp to detect whether or
	203	* not the directory has been modified
	204	* during the copy operation.
	205	*/
	206	unsigned long version = filp->f_version;
	207
	208	error = filldir(dirent, de->name,
	209	de->name_len,
	210	filp->f_pos,
	211	le32_to_cpu(de->inode),
	212	get_dtype(sb, de->file_type));
	213	if (error)
	214	break;
	215	if (version != filp->f_version)
	216	goto revalidate;
	217	stored ++;
	218	}
	219	filp->f_pos += le16_to_cpu(de->rec_len);
	220	}
	221	offset = 0;
222	brelse (bh);
223	}
224	out:
225	return ret;
226	}
227
228	#ifdef CONFIG_EXT3_INDEX
229	/*
230	* These functions convert from the major/minor hash to an f_pos
231	* value.
232	*
233	* Currently we only use major hash numer. This is unfortunate, but
234	* on 32-bit machines, the same VFS interface is used for lseek and
235	* llseek, so if we use the 64 bit offset, then the 32-bit versions of
236	* lseek/telldir/seekdir will blow out spectacularly, and from within
237	* the ext2 low-level routine, we don't know if we're being called by
238	* a 64-bit version of the system call or the 32-bit version of the
239	* system call. Worse yet, NFSv2 only allows for a 32-bit readdir
240	* cookie. Sigh.
241	*/
242	#define hash2pos(major, minor) (major >> 1)
243	#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
244	#define pos2min_hash(pos) (0)
245
246	/*
247	* This structure holds the nodes of the red-black tree used to store
248	* the directory entry in hash order.
249	*/
250	struct fname {
251	__u32 hash;
252	__u32 minor_hash;
253	struct rb_node rb_hash;
254	struct fname *next;
255	__u32 inode;
256	__u8 name_len;
257	__u8 file_type;
258	char name[0];
259	};
260
261	/*
262	* This functoin implements a non-recursive way of freeing all of the
263	* nodes in the red-black tree.
264	*/
265	static void free_rb_tree_fname(struct rb_root *root)
266	{
267	struct rb_node *n = root->rb_node;
268	struct rb_node *parent;
269	struct fname *fname;
270
271	while (n) {
272	/* Do the node's children first */
273	if ((n)->rb_left) {
274	n = n->rb_left;
275	continue;
276	}
277	if (n->rb_right) {
278	n = n->rb_right;
279	continue;
280	}
281	/*
282	* The node has no children; free it, and then zero
283	* out parent's link to it. Finally go to the
284	* beginning of the loop and try to free the parent
285	* node.
286	*/
52b5108c	287	parent = rb_parent(n);
1da177e4 LT	288	fname = rb_entry(n, struct fname, rb_hash);
	289	while (fname) {
	290	struct fname * old = fname;
	291	fname = fname->next;
	292	kfree (old);
	293	}
	294	if (!parent)
	295	root->rb_node = NULL;
	296	else if (parent->rb_left == n)
	297	parent->rb_left = NULL;
	298	else if (parent->rb_right == n)
	299	parent->rb_right = NULL;
	300	n = parent;
	301	}
	302	root->rb_node = NULL;
	303	}
	304
	305
	306	static struct dir_private_info *create_dir_info(loff_t pos)
	307	{
	308	struct dir_private_info *p;
	309
	310	p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL);
	311	if (!p)
	312	return NULL;
	313	p->root.rb_node = NULL;
	314	p->curr_node = NULL;
	315	p->extra_fname = NULL;
	316	p->last_pos = 0;
	317	p->curr_hash = pos2maj_hash(pos);
	318	p->curr_minor_hash = pos2min_hash(pos);
	319	p->next_hash = 0;
	320	return p;
	321	}
	322
	323	void ext3_htree_free_dir_info(struct dir_private_info *p)
	324	{
	325	free_rb_tree_fname(&p->root);
	326	kfree(p);
	327	}
	328
	329	/*
	330	* Given a directory entry, enter it into the fname rb tree.
	331	*/
	332	int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
	333	__u32 minor_hash,
	334	struct ext3_dir_entry_2 *dirent)
	335	{
	336	struct rb_node *p, parent = NULL;
	337	struct fname * fname, *new_fn;
	338	struct dir_private_info *info;
	339	int len;
	340
	341	info = (struct dir_private_info *) dir_file->private_data;
	342	p = &info->root.rb_node;
	343
	344	/* Create and allocate the fname structure */
	345	len = sizeof(struct fname) + dirent->name_len + 1;
	346	new_fn = kmalloc(len, GFP_KERNEL);
	347	if (!new_fn)
	348	return -ENOMEM;
	349	memset(new_fn, 0, len);
	350	new_fn->hash = hash;
	351	new_fn->minor_hash = minor_hash;
352	new_fn->inode = le32_to_cpu(dirent->inode);
353	new_fn->name_len = dirent->name_len;
354	new_fn->file_type = dirent->file_type;
355	memcpy(new_fn->name, dirent->name, dirent->name_len);
356	new_fn->name[dirent->name_len] = 0;
357
358	while (*p) {
359	parent = *p;
360	fname = rb_entry(parent, struct fname, rb_hash);
361
362	/*
363	* If the hash and minor hash match up, then we put
364	* them on a linked list. This rarely happens...
365	*/
366	if ((new_fn->hash == fname->hash) &&
367	(new_fn->minor_hash == fname->minor_hash)) {
368	new_fn->next = fname->next;
369	fname->next = new_fn;
370	return 0;
371	}
372
373	if (new_fn->hash < fname->hash)
374	p = &(*p)->rb_left;
375	else if (new_fn->hash > fname->hash)
376	p = &(*p)->rb_right;
377	else if (new_fn->minor_hash < fname->minor_hash)
378	p = &(*p)->rb_left;
379	else /* if (new_fn->minor_hash > fname->minor_hash) */
380	p = &(*p)->rb_right;
381	}
382
383	rb_link_node(&new_fn->rb_hash, parent, p);
384	rb_insert_color(&new_fn->rb_hash, &info->root);
385	return 0;
386	}
387
388
389
390	/*
391	* This is a helper function for ext3_dx_readdir. It calls filldir
392	* for all entres on the fname linked list. (Normally there is only
393	* one entry on the linked list, unless there are 62 bit hash collisions.)
394	*/
395	static int call_filldir(struct file * filp, void * dirent,
396	filldir_t filldir, struct fname *fname)
397	{
398	struct dir_private_info *info = filp->private_data;
399	loff_t curr_pos;
400	struct inode *inode = filp->f_dentry->d_inode;
401	struct super_block * sb;
402	int error;
403
404	sb = inode->i_sb;
405
406	if (!fname) {
407	printk("call_filldir: called with null fname?!?\n");
408	return 0;
409	}
410	curr_pos = hash2pos(fname->hash, fname->minor_hash);
411	while (fname) {
412	error = filldir(dirent, fname->name,
413	fname->name_len, curr_pos,
414	fname->inode,
415	get_dtype(sb, fname->file_type));
416	if (error) {
417	filp->f_pos = curr_pos;
418	info->extra_fname = fname->next;
419	return error;
420	}
421	fname = fname->next;
422	}
423	return 0;
424	}
425
426	static int ext3_dx_readdir(struct file * filp,
427	void * dirent, filldir_t filldir)
428	{
429	struct dir_private_info *info = filp->private_data;
430	struct inode *inode = filp->f_dentry->d_inode;
431	struct fname *fname;
432	int ret;
433
434	if (!info) {
435	info = create_dir_info(filp->f_pos);
436	if (!info)
437	return -ENOMEM;
438	filp->private_data = info;
439	}
440
441	if (filp->f_pos == EXT3_HTREE_EOF)
442	return 0; /* EOF */
443
444	/* Some one has messed with f_pos; reset the world */
445	if (info->last_pos != filp->f_pos) {
446	free_rb_tree_fname(&info->root);
447	info->curr_node = NULL;
448	info->extra_fname = NULL;
449	info->curr_hash = pos2maj_hash(filp->f_pos);
450	info->curr_minor_hash = pos2min_hash(filp->f_pos);
451	}
452
453	/*
454	* If there are any leftover names on the hash collision
455	* chain, return them first.
456	*/
457	if (info->extra_fname &&
458	call_filldir(filp, dirent, filldir, info->extra_fname))
459	goto finished;
460
461	if (!info->curr_node)
462	info->curr_node = rb_first(&info->root);
463
464	while (1) {
465	/*
466	* Fill the rbtree if we have no more entries,
467	* or the inode has changed since we last read in the
468	* cached entries.
469	*/
470	if ((!info->curr_node) \|\|
471	(filp->f_version != inode->i_version)) {
472	info->curr_node = NULL;
473	free_rb_tree_fname(&info->root);
474	filp->f_version = inode->i_version;
475	ret = ext3_htree_fill_tree(filp, info->curr_hash,
476	info->curr_minor_hash,
477	&info->next_hash);
478	if (ret < 0)
479	return ret;
480	if (ret == 0) {
481	filp->f_pos = EXT3_HTREE_EOF;
482	break;
483	}
484	info->curr_node = rb_first(&info->root);
485	}
486
487	fname = rb_entry(info->curr_node, struct fname, rb_hash);
488	info->curr_hash = fname->hash;
489	info->curr_minor_hash = fname->minor_hash;
490	if (call_filldir(filp, dirent, filldir, fname))
491	break;
492
493	info->curr_node = rb_next(info->curr_node);
494	if (!info->curr_node) {
495	if (info->next_hash == ~0) {
496	filp->f_pos = EXT3_HTREE_EOF;
497	break;
498	}
499	info->curr_hash = info->next_hash;
500	info->curr_minor_hash = 0;
501	}
502	}
503	finished:
504	info->last_pos = filp->f_pos;
505	return 0;
506	}
507
508	static int ext3_release_dir (struct inode * inode, struct file * filp)
509	{
510	if (filp->private_data)
511	ext3_htree_free_dir_info(filp->private_data);
512
513	return 0;
514	}
515
516	#endif