f2fs: add core directory operations

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

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

2 files changed, 770 insertions, 0 deletions

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
new file mode 100644
index 000000000000..5975568d03df
--- /dev/null
+++ b/fs/f2fs/dir.c
@@ -0,0 +1,672 @@
+/**
+ * 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,
+};
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
new file mode 100644
index 000000000000..098a1963d7c7
--- /dev/null
+++ b/fs/f2fs/hash.c
@@ -0,0 +1,98 @@
+/**
+ * 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;
+}