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Commit 6b4ea016 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: add core directory operations 



this adds core functions to find, add, delete, and link dentries.

Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
parent 57397d86

fs/f2fs/dir.c

0 → 100644
+672 −0
Original line number Original line Diff line number Diff line 
/**

 * fs/f2fs/dir.c

 *

 * Copyright (c) 2012 Samsung Electronics Co., Ltd.

 *             http://www.samsung.com/

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

#include <linux/fs.h>

#include <linux/f2fs_fs.h>

#include "f2fs.h"

#include "acl.h"



static unsigned long dir_blocks(struct inode *inode)

{

	return ((unsigned long long) (i_size_read(inode) + PAGE_CACHE_SIZE - 1))

							>> PAGE_CACHE_SHIFT;

}



static unsigned int dir_buckets(unsigned int level)

{

	if (level < MAX_DIR_HASH_DEPTH / 2)

		return 1 << level;

	else

		return 1 << ((MAX_DIR_HASH_DEPTH / 2) - 1);

}



static unsigned int bucket_blocks(unsigned int level)

{

	if (level < MAX_DIR_HASH_DEPTH / 2)

		return 2;

	else

		return 4;

}



static unsigned char f2fs_filetype_table[F2FS_FT_MAX] = {

	[F2FS_FT_UNKNOWN]	= DT_UNKNOWN,

	[F2FS_FT_REG_FILE]	= DT_REG,

	[F2FS_FT_DIR]		= DT_DIR,

	[F2FS_FT_CHRDEV]	= DT_CHR,

	[F2FS_FT_BLKDEV]	= DT_BLK,

	[F2FS_FT_FIFO]		= DT_FIFO,

	[F2FS_FT_SOCK]		= DT_SOCK,

	[F2FS_FT_SYMLINK]	= DT_LNK,

};



#define S_SHIFT 12

static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {

	[S_IFREG >> S_SHIFT]	= F2FS_FT_REG_FILE,

	[S_IFDIR >> S_SHIFT]	= F2FS_FT_DIR,

	[S_IFCHR >> S_SHIFT]	= F2FS_FT_CHRDEV,

	[S_IFBLK >> S_SHIFT]	= F2FS_FT_BLKDEV,

	[S_IFIFO >> S_SHIFT]	= F2FS_FT_FIFO,

	[S_IFSOCK >> S_SHIFT]	= F2FS_FT_SOCK,

	[S_IFLNK >> S_SHIFT]	= F2FS_FT_SYMLINK,

};



static void set_de_type(struct f2fs_dir_entry *de, struct inode *inode)

{

	mode_t mode = inode->i_mode;

	de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];

}



static unsigned long dir_block_index(unsigned int level, unsigned int idx)

{

	unsigned long i;

	unsigned long bidx = 0;



	for (i = 0; i < level; i++)

		bidx += dir_buckets(i) * bucket_blocks(i);

	bidx += idx * bucket_blocks(level);

	return bidx;

}



static bool early_match_name(const char *name, int namelen,

			f2fs_hash_t namehash, struct f2fs_dir_entry *de)

{

	if (le16_to_cpu(de->name_len) != namelen)

		return false;



	if (le32_to_cpu(de->hash_code) != namehash)

		return false;



	return true;

}



static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,

			const char *name, int namelen, int *max_slots,

			f2fs_hash_t namehash, struct page **res_page)

{

	struct f2fs_dir_entry *de;

	unsigned long bit_pos, end_pos, next_pos;

	struct f2fs_dentry_block *dentry_blk = kmap(dentry_page);

	int slots;



	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,

					NR_DENTRY_IN_BLOCK, 0);

	while (bit_pos < NR_DENTRY_IN_BLOCK) {

		de = &dentry_blk->dentry[bit_pos];

		slots = (le16_to_cpu(de->name_len) + F2FS_NAME_LEN - 1) /

							F2FS_NAME_LEN;



		if (early_match_name(name, namelen, namehash, de)) {

			if (!memcmp(dentry_blk->filename[bit_pos],

							name, namelen)) {

				*res_page = dentry_page;

				goto found;

			}

		}

		next_pos = bit_pos + slots;

		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,

				NR_DENTRY_IN_BLOCK, next_pos);

		if (bit_pos >= NR_DENTRY_IN_BLOCK)

			end_pos = NR_DENTRY_IN_BLOCK;

		else

			end_pos = bit_pos;

		if (*max_slots < end_pos - next_pos)

			*max_slots = end_pos - next_pos;

	}



	de = NULL;

	kunmap(dentry_page);

found:

	return de;

}



static struct f2fs_dir_entry *find_in_level(struct inode *dir,

		unsigned int level, const char *name, int namelen,

			f2fs_hash_t namehash, struct page **res_page)

{

	int s = (namelen + F2FS_NAME_LEN - 1) / F2FS_NAME_LEN;

	unsigned int nbucket, nblock;

	unsigned int bidx, end_block;

	struct page *dentry_page;

	struct f2fs_dir_entry *de = NULL;

	bool room = false;

	int max_slots = 0;



	BUG_ON(level > MAX_DIR_HASH_DEPTH);



	nbucket = dir_buckets(level);

	nblock = bucket_blocks(level);



	bidx = dir_block_index(level, namehash % nbucket);

	end_block = bidx + nblock;



	for (; bidx < end_block; bidx++) {

		/* no need to allocate new dentry pages to all the indices */

		dentry_page = find_data_page(dir, bidx);

		if (IS_ERR(dentry_page)) {

			room = true;

			continue;

		}



		de = find_in_block(dentry_page, name, namelen,

					&max_slots, namehash, res_page);

		if (de)

			break;



		if (max_slots >= s)

			room = true;

		f2fs_put_page(dentry_page, 0);

	}



	if (!de && room && F2FS_I(dir)->chash != namehash) {

		F2FS_I(dir)->chash = namehash;

		F2FS_I(dir)->clevel = level;

	}



	return de;

}



/*

 * Find an entry in the specified directory with the wanted name.

 * It returns the page where the entry was found (as a parameter - res_page),

 * and the entry itself. Page is returned mapped and unlocked.

 * Entry is guaranteed to be valid.

 */

struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,

			struct qstr *child, struct page **res_page)

{

	const char *name = child->name;

	int namelen = child->len;

	unsigned long npages = dir_blocks(dir);

	struct f2fs_dir_entry *de = NULL;

	f2fs_hash_t name_hash;

	unsigned int max_depth;

	unsigned int level;



	if (npages == 0)

		return NULL;



	*res_page = NULL;



	name_hash = f2fs_dentry_hash(name, namelen);

	max_depth = F2FS_I(dir)->i_current_depth;



	for (level = 0; level < max_depth; level++) {

		de = find_in_level(dir, level, name,

				namelen, name_hash, res_page);

		if (de)

			break;

	}

	if (!de && F2FS_I(dir)->chash != name_hash) {

		F2FS_I(dir)->chash = name_hash;

		F2FS_I(dir)->clevel = level - 1;

	}

	return de;

}



struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)

{

	struct page *page = NULL;

	struct f2fs_dir_entry *de = NULL;

	struct f2fs_dentry_block *dentry_blk = NULL;



	page = get_lock_data_page(dir, 0);

	if (IS_ERR(page))

		return NULL;



	dentry_blk = kmap(page);

	de = &dentry_blk->dentry[1];

	*p = page;

	unlock_page(page);

	return de;

}



ino_t f2fs_inode_by_name(struct inode *dir, struct qstr *qstr)

{

	ino_t res = 0;

	struct f2fs_dir_entry *de;

	struct page *page;



	de = f2fs_find_entry(dir, qstr, &page);

	if (de) {

		res = le32_to_cpu(de->ino);

		kunmap(page);

		f2fs_put_page(page, 0);

	}



	return res;

}



void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,

		struct page *page, struct inode *inode)

{

	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);



	mutex_lock_op(sbi, DENTRY_OPS);

	lock_page(page);

	wait_on_page_writeback(page);

	de->ino = cpu_to_le32(inode->i_ino);

	set_de_type(de, inode);

	kunmap(page);

	set_page_dirty(page);

	dir->i_mtime = dir->i_ctime = CURRENT_TIME;

	mark_inode_dirty(dir);

	f2fs_put_page(page, 1);

	mutex_unlock_op(sbi, DENTRY_OPS);

}



void init_dent_inode(struct dentry *dentry, struct page *ipage)

{

	struct inode *dir = dentry->d_parent->d_inode;

	struct f2fs_node *rn;



	if (IS_ERR(ipage))

		return;



	wait_on_page_writeback(ipage);



	/* copy dentry info. to this inode page */

	rn = (struct f2fs_node *)page_address(ipage);

	rn->i.i_pino = cpu_to_le32(dir->i_ino);

	rn->i.i_namelen = cpu_to_le32(dentry->d_name.len);

	memcpy(rn->i.i_name, dentry->d_name.name, dentry->d_name.len);

	set_page_dirty(ipage);

}



static int init_inode_metadata(struct inode *inode, struct dentry *dentry)

{

	struct inode *dir = dentry->d_parent->d_inode;



	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {

		int err;

		err = new_inode_page(inode, dentry);

		if (err)

			return err;



		if (S_ISDIR(inode->i_mode)) {

			err = f2fs_make_empty(inode, dir);

			if (err) {

				remove_inode_page(inode);

				return err;

			}

		}



		err = f2fs_init_acl(inode, dir);

		if (err) {

			remove_inode_page(inode);

			return err;

		}

	} else {

		struct page *ipage;

		ipage = get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);

		if (IS_ERR(ipage))

			return PTR_ERR(ipage);

		init_dent_inode(dentry, ipage);

		f2fs_put_page(ipage, 1);

	}

	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {

		inc_nlink(inode);

		f2fs_write_inode(inode, NULL);

	}

	return 0;

}



static void update_parent_metadata(struct inode *dir, struct inode *inode,

						unsigned int current_depth)

{

	bool need_dir_update = false;



	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {

		if (S_ISDIR(inode->i_mode)) {

			inc_nlink(dir);

			need_dir_update = true;

		}

		clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);

	}

	dir->i_mtime = dir->i_ctime = CURRENT_TIME;

	if (F2FS_I(dir)->i_current_depth != current_depth) {

		F2FS_I(dir)->i_current_depth = current_depth;

		need_dir_update = true;

	}



	if (need_dir_update)

		f2fs_write_inode(dir, NULL);

	else

		mark_inode_dirty(dir);



	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))

		clear_inode_flag(F2FS_I(inode), FI_INC_LINK);

}



static int room_for_filename(struct f2fs_dentry_block *dentry_blk, int slots)

{

	int bit_start = 0;

	int zero_start, zero_end;

next:

	zero_start = find_next_zero_bit_le(&dentry_blk->dentry_bitmap,

						NR_DENTRY_IN_BLOCK,

						bit_start);

	if (zero_start >= NR_DENTRY_IN_BLOCK)

		return NR_DENTRY_IN_BLOCK;



	zero_end = find_next_bit_le(&dentry_blk->dentry_bitmap,

						NR_DENTRY_IN_BLOCK,

						zero_start);

	if (zero_end - zero_start >= slots)

		return zero_start;



	bit_start = zero_end + 1;



	if (zero_end + 1 >= NR_DENTRY_IN_BLOCK)

		return NR_DENTRY_IN_BLOCK;

	goto next;

}



int f2fs_add_link(struct dentry *dentry, struct inode *inode)

{

	unsigned int bit_pos;

	unsigned int level;

	unsigned int current_depth;

	unsigned long bidx, block;

	f2fs_hash_t dentry_hash;

	struct f2fs_dir_entry *de;

	unsigned int nbucket, nblock;

	struct inode *dir = dentry->d_parent->d_inode;

	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);

	const char *name = dentry->d_name.name;

	int namelen = dentry->d_name.len;

	struct page *dentry_page = NULL;

	struct f2fs_dentry_block *dentry_blk = NULL;

	int slots = (namelen + F2FS_NAME_LEN - 1) / F2FS_NAME_LEN;

	int err = 0;

	int i;



	dentry_hash = f2fs_dentry_hash(name, dentry->d_name.len);

	level = 0;

	current_depth = F2FS_I(dir)->i_current_depth;

	if (F2FS_I(dir)->chash == dentry_hash) {

		level = F2FS_I(dir)->clevel;

		F2FS_I(dir)->chash = 0;

	}



start:

	if (current_depth == MAX_DIR_HASH_DEPTH)

		return -ENOSPC;



	/* Increase the depth, if required */

	if (level == current_depth)

		++current_depth;



	nbucket = dir_buckets(level);

	nblock = bucket_blocks(level);



	bidx = dir_block_index(level, (dentry_hash % nbucket));



	for (block = bidx; block <= (bidx + nblock - 1); block++) {

		mutex_lock_op(sbi, DENTRY_OPS);

		dentry_page = get_new_data_page(dir, block, true);

		if (IS_ERR(dentry_page)) {

			mutex_unlock_op(sbi, DENTRY_OPS);

			return PTR_ERR(dentry_page);

		}



		dentry_blk = kmap(dentry_page);

		bit_pos = room_for_filename(dentry_blk, slots);

		if (bit_pos < NR_DENTRY_IN_BLOCK)

			goto add_dentry;



		kunmap(dentry_page);

		f2fs_put_page(dentry_page, 1);

		mutex_unlock_op(sbi, DENTRY_OPS);

	}



	/* Move to next level to find the empty slot for new dentry */

	++level;

	goto start;

add_dentry:

	err = init_inode_metadata(inode, dentry);

	if (err)

		goto fail;



	wait_on_page_writeback(dentry_page);



	de = &dentry_blk->dentry[bit_pos];

	de->hash_code = cpu_to_le32(dentry_hash);

	de->name_len = cpu_to_le16(namelen);

	memcpy(dentry_blk->filename[bit_pos], name, namelen);

	de->ino = cpu_to_le32(inode->i_ino);

	set_de_type(de, inode);

	for (i = 0; i < slots; i++)

		test_and_set_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);

	set_page_dirty(dentry_page);

	update_parent_metadata(dir, inode, current_depth);

fail:

	kunmap(dentry_page);

	f2fs_put_page(dentry_page, 1);

	mutex_unlock_op(sbi, DENTRY_OPS);

	return err;

}



/**

 * It only removes the dentry from the dentry page,corresponding name

 * entry in name page does not need to be touched during deletion.

 */

void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,

						struct inode *inode)

{

	struct	f2fs_dentry_block *dentry_blk;

	unsigned int bit_pos;

	struct address_space *mapping = page->mapping;

	struct inode *dir = mapping->host;

	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);

	int slots = (le16_to_cpu(dentry->name_len) + F2FS_NAME_LEN - 1) /

							F2FS_NAME_LEN;

	void *kaddr = page_address(page);

	int i;



	mutex_lock_op(sbi, DENTRY_OPS);



	lock_page(page);

	wait_on_page_writeback(page);



	dentry_blk = (struct f2fs_dentry_block *)kaddr;

	bit_pos = dentry - (struct f2fs_dir_entry *)dentry_blk->dentry;

	for (i = 0; i < slots; i++)

		test_and_clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);



	/* Let's check and deallocate this dentry page */

	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,

			NR_DENTRY_IN_BLOCK,

			0);

	kunmap(page); /* kunmap - pair of f2fs_find_entry */

	set_page_dirty(page);



	dir->i_ctime = dir->i_mtime = CURRENT_TIME;



	if (inode && S_ISDIR(inode->i_mode)) {

		drop_nlink(dir);

		f2fs_write_inode(dir, NULL);

	} else {

		mark_inode_dirty(dir);

	}



	if (inode) {

		inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;

		drop_nlink(inode);

		if (S_ISDIR(inode->i_mode)) {

			drop_nlink(inode);

			i_size_write(inode, 0);

		}

		f2fs_write_inode(inode, NULL);

		if (inode->i_nlink == 0)

			add_orphan_inode(sbi, inode->i_ino);

	}



	if (bit_pos == NR_DENTRY_IN_BLOCK) {

		loff_t page_offset;

		truncate_hole(dir, page->index, page->index + 1);

		clear_page_dirty_for_io(page);

		ClearPageUptodate(page);

		dec_page_count(sbi, F2FS_DIRTY_DENTS);

		inode_dec_dirty_dents(dir);

		page_offset = page->index << PAGE_CACHE_SHIFT;

		f2fs_put_page(page, 1);

	} else {

		f2fs_put_page(page, 1);

	}

	mutex_unlock_op(sbi, DENTRY_OPS);

}



int f2fs_make_empty(struct inode *inode, struct inode *parent)

{

	struct page *dentry_page;

	struct f2fs_dentry_block *dentry_blk;

	struct f2fs_dir_entry *de;

	void *kaddr;



	dentry_page = get_new_data_page(inode, 0, true);

	if (IS_ERR(dentry_page))

		return PTR_ERR(dentry_page);



	kaddr = kmap_atomic(dentry_page);

	dentry_blk = (struct f2fs_dentry_block *)kaddr;



	de = &dentry_blk->dentry[0];

	de->name_len = cpu_to_le16(1);

	de->hash_code = 0;

	de->ino = cpu_to_le32(inode->i_ino);

	memcpy(dentry_blk->filename[0], ".", 1);

	set_de_type(de, inode);



	de = &dentry_blk->dentry[1];

	de->hash_code = 0;

	de->name_len = cpu_to_le16(2);

	de->ino = cpu_to_le32(parent->i_ino);

	memcpy(dentry_blk->filename[1], "..", 2);

	set_de_type(de, inode);



	test_and_set_bit_le(0, &dentry_blk->dentry_bitmap);

	test_and_set_bit_le(1, &dentry_blk->dentry_bitmap);

	kunmap_atomic(kaddr);



	set_page_dirty(dentry_page);

	f2fs_put_page(dentry_page, 1);

	return 0;

}



bool f2fs_empty_dir(struct inode *dir)

{

	unsigned long bidx;

	struct page *dentry_page;

	unsigned int bit_pos;

	struct	f2fs_dentry_block *dentry_blk;

	unsigned long nblock = dir_blocks(dir);



	for (bidx = 0; bidx < nblock; bidx++) {

		void *kaddr;

		dentry_page = get_lock_data_page(dir, bidx);

		if (IS_ERR(dentry_page)) {

			if (PTR_ERR(dentry_page) == -ENOENT)

				continue;

			else

				return false;

		}



		kaddr = kmap_atomic(dentry_page);

		dentry_blk = (struct f2fs_dentry_block *)kaddr;

		if (bidx == 0)

			bit_pos = 2;

		else

			bit_pos = 0;

		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,

						NR_DENTRY_IN_BLOCK,

						bit_pos);

		kunmap_atomic(kaddr);



		f2fs_put_page(dentry_page, 1);



		if (bit_pos < NR_DENTRY_IN_BLOCK)

			return false;

	}

	return true;

}



static int f2fs_readdir(struct file *file, void *dirent, filldir_t filldir)

{

	unsigned long pos = file->f_pos;

	struct inode *inode = file->f_dentry->d_inode;

	unsigned long npages = dir_blocks(inode);

	unsigned char *types = NULL;

	unsigned int bit_pos = 0, start_bit_pos = 0;

	int over = 0;

	struct f2fs_dentry_block *dentry_blk = NULL;

	struct f2fs_dir_entry *de = NULL;

	struct page *dentry_page = NULL;

	unsigned int n = 0;

	unsigned char d_type = DT_UNKNOWN;

	int slots;



	types = f2fs_filetype_table;

	bit_pos = (pos % NR_DENTRY_IN_BLOCK);

	n = (pos / NR_DENTRY_IN_BLOCK);



	for ( ; n < npages; n++) {

		dentry_page = get_lock_data_page(inode, n);

		if (IS_ERR(dentry_page))

			continue;



		start_bit_pos = bit_pos;

		dentry_blk = kmap(dentry_page);

		while (bit_pos < NR_DENTRY_IN_BLOCK) {

			d_type = DT_UNKNOWN;

			bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,

							NR_DENTRY_IN_BLOCK,

							bit_pos);

			if (bit_pos >= NR_DENTRY_IN_BLOCK)

				break;



			de = &dentry_blk->dentry[bit_pos];

			if (types && de->file_type < F2FS_FT_MAX)

				d_type = types[de->file_type];



			over = filldir(dirent,

					dentry_blk->filename[bit_pos],

					le16_to_cpu(de->name_len),

					(n * NR_DENTRY_IN_BLOCK) + bit_pos,

					le32_to_cpu(de->ino), d_type);

			if (over) {

				file->f_pos += bit_pos - start_bit_pos;

				goto success;

			}

			slots = (le16_to_cpu(de->name_len) + F2FS_NAME_LEN - 1)

								/ F2FS_NAME_LEN;

			bit_pos += slots;

		}

		bit_pos = 0;

		file->f_pos = (n + 1) * NR_DENTRY_IN_BLOCK;

		kunmap(dentry_page);

		f2fs_put_page(dentry_page, 1);

		dentry_page = NULL;

	}

success:

	if (dentry_page && !IS_ERR(dentry_page)) {

		kunmap(dentry_page);

		f2fs_put_page(dentry_page, 1);

	}



	return 0;

}



const struct file_operations f2fs_dir_operations = {

	.llseek		= generic_file_llseek,

	.read		= generic_read_dir,

	.readdir	= f2fs_readdir,

	.fsync		= f2fs_sync_file,

	.unlocked_ioctl	= f2fs_ioctl,

};

fs/f2fs/hash.c

0 → 100644
+98 −0
Original line number Original line Diff line number Diff line 
/**

 * fs/f2fs/hash.c

 *

 * Copyright (c) 2012 Samsung Electronics Co., Ltd.

 *             http://www.samsung.com/

 *

 * Portions of this code from linux/fs/ext3/hash.c

 *

 * Copyright (C) 2002 by Theodore Ts'o

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

#include <linux/types.h>

#include <linux/fs.h>

#include <linux/f2fs_fs.h>

#include <linux/cryptohash.h>

#include <linux/pagemap.h>



#include "f2fs.h"



/*

 * Hashing code copied from ext3

 */

#define DELTA 0x9E3779B9



static void TEA_transform(unsigned int buf[4], unsigned int const in[])

{

	__u32 sum = 0;

	__u32 b0 = buf[0], b1 = buf[1];

	__u32 a = in[0], b = in[1], c = in[2], d = in[3];

	int n = 16;



	do {

		sum += DELTA;

		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);

		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);

	} while (--n);



	buf[0] += b0;

	buf[1] += b1;

}



static void str2hashbuf(const char *msg, int len, unsigned int *buf, int num)

{

	unsigned pad, val;

	int i;



	pad = (__u32)len | ((__u32)len << 8);

	pad |= pad << 16;



	val = pad;

	if (len > num * 4)

		len = num * 4;

	for (i = 0; i < len; i++) {

		if ((i % 4) == 0)

			val = pad;

		val = msg[i] + (val << 8);

		if ((i % 4) == 3) {

			*buf++ = val;

			val = pad;

			num--;

		}

	}

	if (--num >= 0)

		*buf++ = val;

	while (--num >= 0)

		*buf++ = pad;

}



f2fs_hash_t f2fs_dentry_hash(const char *name, int len)

{

	__u32 hash, minor_hash;

	f2fs_hash_t f2fs_hash;

	const char *p;

	__u32 in[8], buf[4];



	/* Initialize the default seed for the hash checksum functions */

	buf[0] = 0x67452301;

	buf[1] = 0xefcdab89;

	buf[2] = 0x98badcfe;

	buf[3] = 0x10325476;



	p = name;

	while (len > 0) {

		str2hashbuf(p, len, in, 4);

		TEA_transform(buf, in);

		len -= 16;

		p += 16;

	}

	hash = buf[0];

	minor_hash = buf[1];



	f2fs_hash = hash;

	f2fs_hash &= ~F2FS_HASH_COL_BIT;

	return f2fs_hash;

}