[linux.git] / fs / ext3 / dir.c

/*
 *  linux/fs/ext3/dir.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([email protected])
 * 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 ([email protected]), 1995
 *
 * Hash Tree Directory indexing (c) 2001  Daniel Phillips
 *
 */

#include <linux/compat.h>
#include "ext3.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_dx_readdir(struct file * filp,
			   void * dirent, filldir_t filldir);

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]);
}

/**
 * Check if the given dir-inode refers to an htree-indexed directory
 * (or a directory which chould potentially get coverted to use htree
 * indexing).
 *
 * Return 1 if it is a dx dir, 0 if not
 */
static int is_dx_dir(struct inode *inode)
{
	struct super_block *sb = inode->i_sb;

	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)))
		return 1;

	return 0;
}

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 = ext3_rec_len_from_disk(de->rec_len);

	if (unlikely(rlen < EXT3_DIR_REC_LEN(1)))
		error_msg = "rec_len is smaller than minimal";
	else if (unlikely(rlen % 4 != 0))
		error_msg = "rec_len % 4 != 0";
	else if (unlikely(rlen < EXT3_DIR_REC_LEN(de->name_len)))
		error_msg = "rec_len is too small for name_len";
	else if (unlikely((((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)))
		error_msg = "directory entry across blocks";
	else if (unlikely(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 (unlikely(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;
	int err;
	struct inode *inode = file_inode(filp);
	struct super_block *sb = inode->i_sb;
	int ret = 0;
	int dir_has_error = 0;

	if (is_dx_dir(inode)) {
		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(file_inode(filp))->i_flags &= ~EXT3_INDEX_FL;
	}
	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);
		if (err > 0) {
			pgoff_t index = map_bh.b_blocknr >>
					(PAGE_CACHE_SHIFT - inode->i_blkbits);
			if (!ra_has_index(&filp->f_ra, index))
				page_cache_sync_readahead(
					sb->s_bdev->bd_inode->i_mapping,
					&filp->f_ra, filp,
					index, 1);
			filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
			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) {
			if (!dir_has_error) {
				ext3_error(sb, __func__, "directory #%lu "
					"contains a hole at offset %lld",
					inode->i_ino, filp->f_pos);
				dir_has_error = 1;
			}
			/* corrupt size?  Maybe no more blocks to read */
			if (filp->f_pos > inode->i_blocks << 9)
				break;
			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 (ext3_rec_len_from_disk(de->rec_len) <
						EXT3_DIR_REC_LEN(1))
					break;
				i += ext3_rec_len_from_disk(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 += ext3_rec_len_from_disk(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.
				 */
				u64 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 += ext3_rec_len_from_disk(de->rec_len);
		}
		offset = 0;
		brelse (bh);
	}
out:
	return ret;
}

static inline int is_32bit_api(void)
{
#ifdef CONFIG_COMPAT
	return is_compat_task();
#else
	return (BITS_PER_LONG == 32);
#endif
}

/*
 * These functions convert from the major/minor hash to an f_pos
 * value for dx directories
 *
 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
 * FMODE_64BITHASH explicitly. On the other hand, we allow ext3 to be mounted
 * directly on both 32-bit and 64-bit nodes, under such case, neither
 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
 */
static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
{
	if ((filp->f_mode & FMODE_32BITHASH) ||
	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
		return major >> 1;
	else
		return ((__u64)(major >> 1) << 32) | (__u64)minor;
}

static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
{
	if ((filp->f_mode & FMODE_32BITHASH) ||
	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
		return (pos << 1) & 0xffffffff;
	else
		return ((pos >> 32) << 1) & 0xffffffff;
}

static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
{
	if ((filp->f_mode & FMODE_32BITHASH) ||
	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
		return 0;
	else
		return pos & 0xffffffff;
}

/*
 * Return 32- or 64-bit end-of-file for dx directories
 */
static inline loff_t ext3_get_htree_eof(struct file *filp)
{
	if ((filp->f_mode & FMODE_32BITHASH) ||
	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
		return EXT3_HTREE_EOF_32BIT;
	else
		return EXT3_HTREE_EOF_64BIT;
}


/*
 * ext3_dir_llseek() calls generic_file_llseek[_size]() to handle both
 * non-htree and htree directories, where the "offset" is in terms
 * of the filename hash value instead of the byte offset.
 *
 * Because we may return a 64-bit hash that is well beyond s_maxbytes,
 * we need to pass the max hash as the maximum allowable offset in
 * the htree directory case.
 *
 * NOTE: offsets obtained *before* ext3_set_inode_flag(dir, EXT3_INODE_INDEX)
 *       will be invalid once the directory was converted into a dx directory
 */
loff_t ext3_dir_llseek(struct file *file, loff_t offset, int whence)
{
	struct inode *inode = file->f_mapping->host;
	int dx_dir = is_dx_dir(inode);
	loff_t htree_max = ext3_get_htree_eof(file);

	if (likely(dx_dir))
		return generic_file_llseek_size(file, offset, whence,
					        htree_max, htree_max);
	else
		return generic_file_llseek(file, offset, whence);
}

/*
 * 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_ROOT;
		else if (parent->rb_left == n)
			parent->rb_left = NULL;
		else if (parent->rb_right == n)
			parent->rb_right = NULL;
		n = parent;
	}
}


static struct dir_private_info *ext3_htree_create_dir_info(struct file *filp,
							   loff_t pos)
{
	struct dir_private_info *p;

	p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
	if (!p)
		return NULL;
	p->curr_hash = pos2maj_hash(filp, pos);
	p->curr_minor_hash = pos2min_hash(filp, pos);
	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 = kzalloc(len, GFP_KERNEL);
	if (!new_fn)
		return -ENOMEM;
	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 = file_inode(filp);
	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(filp, 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;
			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 = file_inode(filp);
	struct fname *fname;
	int	ret;

	if (!info) {
		info = ext3_htree_create_dir_info(filp, filp->f_pos);
		if (!info)
			return -ENOMEM;
		filp->private_data = info;
	}

	if (filp->f_pos == ext3_get_htree_eof(filp))
		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, filp->f_pos);
		info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
	}

	/*
	 * If there are any leftover names on the hash collision
	 * chain, return them first.
	 */
	if (info->extra_fname) {
		if (call_filldir(filp, dirent, filldir, info->extra_fname))
			goto finished;
		info->extra_fname = NULL;
		goto next_node;
	} else 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_get_htree_eof(filp);
				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;
	next_node:
		info->curr_node = rb_next(info->curr_node);
		if (info->curr_node) {
			fname = rb_entry(info->curr_node, struct fname,
					 rb_hash);
			info->curr_hash = fname->hash;
			info->curr_minor_hash = fname->minor_hash;
		} else {
			if (info->next_hash == ~0) {
				filp->f_pos = ext3_get_htree_eof(filp);
				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;
}

const struct file_operations ext3_dir_operations = {
	.llseek		= ext3_dir_llseek,
	.read		= generic_read_dir,
	.readdir	= ext3_readdir,
	.unlocked_ioctl = ext3_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= ext3_compat_ioctl,
#endif
	.fsync		= ext3_sync_file,
	.release	= ext3_release_dir,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/ext3/dir.c
	3	*
	4	* Copyright (C) 1992, 1993, 1994, 1995
	5	* Remy Card ([email protected])
	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 ([email protected]), 1995
	19	*
	20	* Hash Tree Directory indexing (c) 2001 Daniel Phillips
	21	*
	22	*/
	23
d7dab39b	24	#include <linux/compat.h>
4613ad18	25	#include "ext3.h"
1da177e4 LT	26
	27	static unsigned char ext3_filetype_table[] = {
	28	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
	29	};
	30
1da177e4 LT	31	static int ext3_dx_readdir(struct file * filp,
1da177e4 LT	32	void * dirent, filldir_t filldir);
1da177e4 LT	33
	34	static unsigned char get_dtype(struct super_block *sb, int filetype)
	35	{
	36	if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE) \|\|
	37	(filetype >= EXT3_FT_MAX))
	38	return DT_UNKNOWN;
	39
	40	return (ext3_filetype_table[filetype]);
	41	}
ae6ddcc5	42
d7dab39b ES	43	/**
	44	* Check if the given dir-inode refers to an htree-indexed directory
	45	* (or a directory which chould potentially get coverted to use htree
	46	* indexing).
	47	*
	48	* Return 1 if it is a dx dir, 0 if not
	49	*/
	50	static int is_dx_dir(struct inode *inode)
	51	{
	52	struct super_block *sb = inode->i_sb;
	53
	54	if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
	55	EXT3_FEATURE_COMPAT_DIR_INDEX) &&
	56	((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) \|\|
	57	((inode->i_size >> sb->s_blocksize_bits) == 1)))
	58	return 1;
	59
	60	return 0;
	61	}
1da177e4 LT	62
	63	int ext3_check_dir_entry (const char * function, struct inode * dir,
	64	struct ext3_dir_entry_2 * de,
	65	struct buffer_head * bh,
	66	unsigned long offset)
	67	{
	68	const char * error_msg = NULL;
7c06a8dc	69	const int rlen = ext3_rec_len_from_disk(de->rec_len);
1da177e4	70
a4ae3094	71	if (unlikely(rlen < EXT3_DIR_REC_LEN(1)))
1da177e4	72	error_msg = "rec_len is smaller than minimal";
a4ae3094	73	else if (unlikely(rlen % 4 != 0))
1da177e4	74	error_msg = "rec_len % 4 != 0";
a4ae3094	75	else if (unlikely(rlen < EXT3_DIR_REC_LEN(de->name_len)))
1da177e4	76	error_msg = "rec_len is too small for name_len";
a4ae3094	77	else if (unlikely((((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)))
1da177e4	78	error_msg = "directory entry across blocks";
a4ae3094 ES	79	else if (unlikely(le32_to_cpu(de->inode) >
a4ae3094 ES	80	le32_to_cpu(EXT3_SB(dir->i_sb)->s_es->s_inodes_count)))
1da177e4 LT	81	error_msg = "inode out of bounds";
1da177e4 LT	82
a4ae3094	83	if (unlikely(error_msg != NULL))
1da177e4 LT	84	ext3_error (dir->i_sb, function,
	85	"bad entry in directory #%lu: %s - "
	86	"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
	87	dir->i_ino, error_msg, offset,
	88	(unsigned long) le32_to_cpu(de->inode),
	89	rlen, de->name_len);
a4ae3094	90
1da177e4 LT	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;
1da177e4	101	int err;
496ad9aa	102	struct inode *inode = file_inode(filp);
d7dab39b	103	struct super_block *sb = inode->i_sb;
1da177e4	104	int ret = 0;
cdbf6dba	105	int dir_has_error = 0;
1da177e4	106
d7dab39b	107	if (is_dx_dir(inode)) {
1da177e4 LT	108	err = ext3_dx_readdir(filp, dirent, filldir);
	109	if (err != ERR_BAD_DX_DIR) {
	110	ret = err;
	111	goto out;
	112	}
	113	/*
	114	* We don't set the inode dirty flag since it's not
	115	* critical that it get flushed back to the disk.
	116	*/
496ad9aa	117	EXT3_I(file_inode(filp))->i_flags &= ~EXT3_INDEX_FL;
1da177e4	118	}
1da177e4	119	stored = 0;
1da177e4 LT	120	offset = filp->f_pos & (sb->s_blocksize - 1);
	121
	122	while (!error && !stored && filp->f_pos < inode->i_size) {
d8733c29 AM	123	unsigned long blk = filp->f_pos >> EXT3_BLOCK_SIZE_BITS(sb);
	124	struct buffer_head map_bh;
	125	struct buffer_head *bh = NULL;
	126
	127	map_bh.b_state = 0;
43237b54	128	err = ext3_get_blocks_handle(NULL, inode, blk, 1, &map_bh, 0);
89747d36	129	if (err > 0) {
dc7868fc FW	130	pgoff_t index = map_bh.b_blocknr >>
	131	(PAGE_CACHE_SHIFT - inode->i_blkbits);
	132	if (!ra_has_index(&filp->f_ra, index))
cf914a7d	133	page_cache_sync_readahead(
dc7868fc FW	134	sb->s_bdev->bd_inode->i_mapping,
dc7868fc FW	135	&filp->f_ra, filp,
cf914a7d	136	index, 1);
f4e6b498	137	filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
d8733c29 AM	138	bh = ext3_bread(NULL, inode, blk, 0, &err);
	139	}
	140
	141	/*
	142	* We ignore I/O errors on directories so users have a chance
	143	* of recovering data when there's a bad sector
	144	*/
1da177e4	145	if (!bh) {
cdbf6dba ES	146	if (!dir_has_error) {
	147	ext3_error(sb, __func__, "directory #%lu "
	148	"contains a hole at offset %lld",
	149	inode->i_ino, filp->f_pos);
	150	dir_has_error = 1;
	151	}
40b85134 ES	152	/* corrupt size? Maybe no more blocks to read */
	153	if (filp->f_pos > inode->i_blocks << 9)
	154	break;
1da177e4 LT	155	filp->f_pos += sb->s_blocksize - offset;
	156	continue;
	157	}
	158
1da177e4 LT	159	revalidate:
	160	/* If the dir block has changed since the last call to
	161	* readdir(2), then we might be pointing to an invalid
	162	* dirent right now. Scan from the start of the block
	163	* to make sure. */
	164	if (filp->f_version != inode->i_version) {
	165	for (i = 0; i < sb->s_blocksize && i < offset; ) {
ae6ddcc5	166	de = (struct ext3_dir_entry_2 *)
1da177e4 LT	167	(bh->b_data + i);
	168	/* It's too expensive to do a full
	169	* dirent test each time round this
	170	* loop, but we do have to test at
	171	* least that it is non-zero. A
	172	* failure will be detected in the
	173	* dirent test below. */
7c06a8dc	174	if (ext3_rec_len_from_disk(de->rec_len) <
1da177e4 LT	175	EXT3_DIR_REC_LEN(1))
1da177e4 LT	176	break;
7c06a8dc	177	i += ext3_rec_len_from_disk(de->rec_len);
1da177e4 LT	178	}
	179	offset = i;
	180	filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
	181	\| offset;
	182	filp->f_version = inode->i_version;
	183	}
	184
ae6ddcc5	185	while (!error && filp->f_pos < inode->i_size
1da177e4 LT	186	&& offset < sb->s_blocksize) {
	187	de = (struct ext3_dir_entry_2 *) (bh->b_data + offset);
	188	if (!ext3_check_dir_entry ("ext3_readdir", inode, de,
	189	bh, offset)) {
	190	/* On error, skip the f_pos to the
	191	next block. */
	192	filp->f_pos = (filp->f_pos \|
	193	(sb->s_blocksize - 1)) + 1;
	194	brelse (bh);
	195	ret = stored;
	196	goto out;
	197	}
7c06a8dc	198	offset += ext3_rec_len_from_disk(de->rec_len);
1da177e4 LT	199	if (le32_to_cpu(de->inode)) {
	200	/* We might block in the next section
	201	* if the data destination is
	202	* currently swapped out. So, use a
	203	* version stamp to detect whether or
	204	* not the directory has been modified
	205	* during the copy operation.
	206	*/
2b47c361	207	u64 version = filp->f_version;
1da177e4 LT	208
	209	error = filldir(dirent, de->name,
	210	de->name_len,
	211	filp->f_pos,
	212	le32_to_cpu(de->inode),
	213	get_dtype(sb, de->file_type));
	214	if (error)
	215	break;
	216	if (version != filp->f_version)
	217	goto revalidate;
	218	stored ++;
	219	}
7c06a8dc	220	filp->f_pos += ext3_rec_len_from_disk(de->rec_len);
1da177e4 LT	221	}
	222	offset = 0;
	223	brelse (bh);
	224	}
	225	out:
	226	return ret;
	227	}
	228
d7dab39b ES	229	static inline int is_32bit_api(void)
	230	{
	231	#ifdef CONFIG_COMPAT
	232	return is_compat_task();
	233	#else
	234	return (BITS_PER_LONG == 32);
	235	#endif
	236	}
	237
1da177e4 LT	238	/*
1da177e4 LT	239	* These functions convert from the major/minor hash to an f_pos
d7dab39b	240	* value for dx directories
ae6ddcc5	241	*
d7dab39b ES	242	* Upper layer (for example NFS) should specify FMODE_32BITHASH or
	243	* FMODE_64BITHASH explicitly. On the other hand, we allow ext3 to be mounted
	244	* directly on both 32-bit and 64-bit nodes, under such case, neither
	245	* FMODE_32BITHASH nor FMODE_64BITHASH is specified.
1da177e4	246	*/
d7dab39b ES	247	static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
	248	{
	249	if ((filp->f_mode & FMODE_32BITHASH) \|\|
	250	(!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
	251	return major >> 1;
	252	else
	253	return ((__u64)(major >> 1) << 32) \| (__u64)minor;
	254	}
	255
	256	static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
	257	{
	258	if ((filp->f_mode & FMODE_32BITHASH) \|\|
	259	(!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
	260	return (pos << 1) & 0xffffffff;
	261	else
	262	return ((pos >> 32) << 1) & 0xffffffff;
	263	}
	264
	265	static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
	266	{
	267	if ((filp->f_mode & FMODE_32BITHASH) \|\|
	268	(!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
	269	return 0;
	270	else
	271	return pos & 0xffffffff;
	272	}
	273
	274	/*
	275	* Return 32- or 64-bit end-of-file for dx directories
	276	*/
	277	static inline loff_t ext3_get_htree_eof(struct file *filp)
	278	{
	279	if ((filp->f_mode & FMODE_32BITHASH) \|\|
	280	(!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
	281	return EXT3_HTREE_EOF_32BIT;
	282	else
	283	return EXT3_HTREE_EOF_64BIT;
	284	}
	285
	286
	287	/*
	288	* ext3_dir_llseek() calls generic_file_llseek[_size]() to handle both
	289	* non-htree and htree directories, where the "offset" is in terms
	290	* of the filename hash value instead of the byte offset.
	291	*
	292	* Because we may return a 64-bit hash that is well beyond s_maxbytes,
	293	* we need to pass the max hash as the maximum allowable offset in
	294	* the htree directory case.
	295	*
	296	* NOTE: offsets obtained before ext3_set_inode_flag(dir, EXT3_INODE_INDEX)
	297	* will be invalid once the directory was converted into a dx directory
	298	*/
965c8e59	299	loff_t ext3_dir_llseek(struct file *file, loff_t offset, int whence)
d7dab39b ES	300	{
	301	struct inode *inode = file->f_mapping->host;
	302	int dx_dir = is_dx_dir(inode);
de9b9422	303	loff_t htree_max = ext3_get_htree_eof(file);
d7dab39b ES	304
d7dab39b ES	305	if (likely(dx_dir))
965c8e59	306	return generic_file_llseek_size(file, offset, whence,
de9b9422	307	htree_max, htree_max);
d7dab39b	308	else
965c8e59	309	return generic_file_llseek(file, offset, whence);
d7dab39b	310	}
1da177e4 LT	311
	312	/*
	313	* This structure holds the nodes of the red-black tree used to store
	314	* the directory entry in hash order.
	315	*/
	316	struct fname {
	317	__u32 hash;
	318	__u32 minor_hash;
ae6ddcc5	319	struct rb_node rb_hash;
1da177e4 LT	320	struct fname *next;
	321	__u32 inode;
	322	__u8 name_len;
	323	__u8 file_type;
	324	char name[0];
	325	};
	326
	327	/*
	328	* This functoin implements a non-recursive way of freeing all of the
	329	* nodes in the red-black tree.
	330	*/
	331	static void free_rb_tree_fname(struct rb_root *root)
	332	{
	333	struct rb_node *n = root->rb_node;
	334	struct rb_node *parent;
	335	struct fname *fname;
	336
	337	while (n) {
	338	/* Do the node's children first */
9ebfbe9f	339	if (n->rb_left) {
1da177e4 LT	340	n = n->rb_left;
	341	continue;
	342	}
	343	if (n->rb_right) {
	344	n = n->rb_right;
	345	continue;
	346	}
	347	/*
	348	* The node has no children; free it, and then zero
	349	* out parent's link to it. Finally go to the
	350	* beginning of the loop and try to free the parent
	351	* node.
	352	*/
52b5108c	353	parent = rb_parent(n);
1da177e4 LT	354	fname = rb_entry(n, struct fname, rb_hash);
	355	while (fname) {
	356	struct fname * old = fname;
	357	fname = fname->next;
	358	kfree (old);
	359	}
	360	if (!parent)
1513b02c	361	*root = RB_ROOT;
1da177e4 LT	362	else if (parent->rb_left == n)
	363	parent->rb_left = NULL;
	364	else if (parent->rb_right == n)
	365	parent->rb_right = NULL;
	366	n = parent;
	367	}
1da177e4 LT	368	}
	369
	370
d7dab39b ES	371	static struct dir_private_info ext3_htree_create_dir_info(struct file filp,
d7dab39b ES	372	loff_t pos)
1da177e4 LT	373	{
	374	struct dir_private_info *p;
	375
9ebfbe9f	376	p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
1da177e4 LT	377	if (!p)
1da177e4 LT	378	return NULL;
d7dab39b ES	379	p->curr_hash = pos2maj_hash(filp, pos);
d7dab39b ES	380	p->curr_minor_hash = pos2min_hash(filp, pos);
1da177e4 LT	381	return p;
	382	}
	383
	384	void ext3_htree_free_dir_info(struct dir_private_info *p)
	385	{
	386	free_rb_tree_fname(&p->root);
	387	kfree(p);
	388	}
	389
	390	/*
	391	* Given a directory entry, enter it into the fname rb tree.
	392	*/
	393	int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
	394	__u32 minor_hash,
	395	struct ext3_dir_entry_2 *dirent)
	396	{
	397	struct rb_node *p, parent = NULL;
	398	struct fname * fname, *new_fn;
	399	struct dir_private_info *info;
	400	int len;
	401
	402	info = (struct dir_private_info *) dir_file->private_data;
	403	p = &info->root.rb_node;
	404
	405	/* Create and allocate the fname structure */
	406	len = sizeof(struct fname) + dirent->name_len + 1;
f8314dc6	407	new_fn = kzalloc(len, GFP_KERNEL);
1da177e4 LT	408	if (!new_fn)
1da177e4 LT	409	return -ENOMEM;
1da177e4 LT	410	new_fn->hash = hash;
	411	new_fn->minor_hash = minor_hash;
	412	new_fn->inode = le32_to_cpu(dirent->inode);
	413	new_fn->name_len = dirent->name_len;
	414	new_fn->file_type = dirent->file_type;
	415	memcpy(new_fn->name, dirent->name, dirent->name_len);
	416	new_fn->name[dirent->name_len] = 0;
	417
	418	while (*p) {
	419	parent = *p;
	420	fname = rb_entry(parent, struct fname, rb_hash);
	421
	422	/*
	423	* If the hash and minor hash match up, then we put
	424	* them on a linked list. This rarely happens...
	425	*/
	426	if ((new_fn->hash == fname->hash) &&
	427	(new_fn->minor_hash == fname->minor_hash)) {
	428	new_fn->next = fname->next;
	429	fname->next = new_fn;
	430	return 0;
	431	}
	432
	433	if (new_fn->hash < fname->hash)
	434	p = &(*p)->rb_left;
	435	else if (new_fn->hash > fname->hash)
	436	p = &(*p)->rb_right;
	437	else if (new_fn->minor_hash < fname->minor_hash)
	438	p = &(*p)->rb_left;
	439	else /* if (new_fn->minor_hash > fname->minor_hash) */
	440	p = &(*p)->rb_right;
	441	}
	442
	443	rb_link_node(&new_fn->rb_hash, parent, p);
	444	rb_insert_color(&new_fn->rb_hash, &info->root);
	445	return 0;
	446	}
	447
	448
	449
	450	/*
	451	* This is a helper function for ext3_dx_readdir. It calls filldir
	452	* for all entres on the fname linked list. (Normally there is only
	453	* one entry on the linked list, unless there are 62 bit hash collisions.)
	454	*/
	455	static int call_filldir(struct file * filp, void * dirent,
	456	filldir_t filldir, struct fname *fname)
	457	{
	458	struct dir_private_info *info = filp->private_data;
	459	loff_t curr_pos;
496ad9aa	460	struct inode *inode = file_inode(filp);
1da177e4 LT	461	struct super_block * sb;
	462	int error;
	463
	464	sb = inode->i_sb;
	465
	466	if (!fname) {
	467	printk("call_filldir: called with null fname?!?\n");
	468	return 0;
	469	}
d7dab39b	470	curr_pos = hash2pos(filp, fname->hash, fname->minor_hash);
1da177e4 LT	471	while (fname) {
1da177e4 LT	472	error = filldir(dirent, fname->name,
ae6ddcc5	473	fname->name_len, curr_pos,
1da177e4 LT	474	fname->inode,
	475	get_dtype(sb, fname->file_type));
	476	if (error) {
	477	filp->f_pos = curr_pos;
6a897cf4	478	info->extra_fname = fname;
1da177e4 LT	479	return error;
	480	}
	481	fname = fname->next;
	482	}
	483	return 0;
	484	}
	485
	486	static int ext3_dx_readdir(struct file * filp,
	487	void * dirent, filldir_t filldir)
	488	{
	489	struct dir_private_info *info = filp->private_data;
496ad9aa	490	struct inode *inode = file_inode(filp);
1da177e4 LT	491	struct fname *fname;
	492	int ret;
	493
	494	if (!info) {
d7dab39b	495	info = ext3_htree_create_dir_info(filp, filp->f_pos);
1da177e4 LT	496	if (!info)
	497	return -ENOMEM;
	498	filp->private_data = info;
	499	}
	500
d7dab39b	501	if (filp->f_pos == ext3_get_htree_eof(filp))
1da177e4 LT	502	return 0; /* EOF */
	503
	504	/* Some one has messed with f_pos; reset the world */
	505	if (info->last_pos != filp->f_pos) {
	506	free_rb_tree_fname(&info->root);
	507	info->curr_node = NULL;
	508	info->extra_fname = NULL;
d7dab39b ES	509	info->curr_hash = pos2maj_hash(filp, filp->f_pos);
d7dab39b ES	510	info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
1da177e4 LT	511	}
	512
	513	/*
	514	* If there are any leftover names on the hash collision
	515	* chain, return them first.
	516	*/
6a897cf4 ED	517	if (info->extra_fname) {
	518	if (call_filldir(filp, dirent, filldir, info->extra_fname))
	519	goto finished;
6a897cf4	520	info->extra_fname = NULL;
8c9fa93d	521	goto next_node;
6a897cf4	522	} else if (!info->curr_node)
1da177e4 LT	523	info->curr_node = rb_first(&info->root);
	524
	525	while (1) {
	526	/*
	527	* Fill the rbtree if we have no more entries,
	528	* or the inode has changed since we last read in the
ae6ddcc5	529	* cached entries.
1da177e4 LT	530	*/
	531	if ((!info->curr_node) \|\|
	532	(filp->f_version != inode->i_version)) {
	533	info->curr_node = NULL;
	534	free_rb_tree_fname(&info->root);
	535	filp->f_version = inode->i_version;
	536	ret = ext3_htree_fill_tree(filp, info->curr_hash,
	537	info->curr_minor_hash,
	538	&info->next_hash);
	539	if (ret < 0)
	540	return ret;
	541	if (ret == 0) {
d7dab39b	542	filp->f_pos = ext3_get_htree_eof(filp);
1da177e4 LT	543	break;
	544	}
	545	info->curr_node = rb_first(&info->root);
	546	}
	547
	548	fname = rb_entry(info->curr_node, struct fname, rb_hash);
	549	info->curr_hash = fname->hash;
	550	info->curr_minor_hash = fname->minor_hash;
	551	if (call_filldir(filp, dirent, filldir, fname))
	552	break;
8c9fa93d	553	next_node:
1da177e4	554	info->curr_node = rb_next(info->curr_node);
8c9fa93d TT	555	if (info->curr_node) {
	556	fname = rb_entry(info->curr_node, struct fname,
	557	rb_hash);
	558	info->curr_hash = fname->hash;
	559	info->curr_minor_hash = fname->minor_hash;
	560	} else {
1da177e4	561	if (info->next_hash == ~0) {
d7dab39b	562	filp->f_pos = ext3_get_htree_eof(filp);
1da177e4 LT	563	break;
	564	}
	565	info->curr_hash = info->next_hash;
	566	info->curr_minor_hash = 0;
	567	}
	568	}
	569	finished:
	570	info->last_pos = filp->f_pos;
	571	return 0;
	572	}
	573
	574	static int ext3_release_dir (struct inode * inode, struct file * filp)
	575	{
	576	if (filp->private_data)
	577	ext3_htree_free_dir_info(filp->private_data);
	578
	579	return 0;
	580	}
d7dab39b ES	581
	582	const struct file_operations ext3_dir_operations = {
	583	.llseek = ext3_dir_llseek,
	584	.read = generic_read_dir,
	585	.readdir = ext3_readdir,
	586	.unlocked_ioctl = ext3_ioctl,
	587	#ifdef CONFIG_COMPAT
	588	.compat_ioctl = ext3_compat_ioctl,
	589	#endif
	590	.fsync = ext3_sync_file,
	591	.release = ext3_release_dir,
	592	};