// SPDX-License-Identifier: LGPL-2.1
/*
 * Copyright (c) 2012 Taobao.
 * Written by Tao Ma <boyu.mt@taobao.com>
 */

#include <linux/iomap.h>
#include <linux/fiemap.h>
#include <linux/iversion.h>

#include "ext4_jbd2.h"
#include "ext4.h"
#include "xattr.h"
#include "truncate.h"

#define EXT4_XATTR_SYSTEM_DATA  "data"
#define EXT4_MIN_INLINE_DATA_SIZE       ((sizeof(__le32) * EXT4_N_BLOCKS))
#define EXT4_INLINE_DOTDOT_OFFSET       2
#define EXT4_INLINE_DOTDOT_SIZE         4

static int ext4_get_inline_size(struct inode *inode)
{
        if (EXT4_I(inode)->i_inline_off)
                return EXT4_I(inode)->i_inline_size;

        return 0;
}

static int get_max_inline_xattr_value_size(struct inode *inode,
                                           struct ext4_iloc *iloc)
{
        struct ext4_xattr_ibody_header *header;
        struct ext4_xattr_entry *entry;
        struct ext4_inode *raw_inode;
        int free, min_offs;

        min_offs = EXT4_SB(inode->i_sb)->s_inode_size -
                        EXT4_GOOD_OLD_INODE_SIZE -
                        EXT4_I(inode)->i_extra_isize -
                        sizeof(struct ext4_xattr_ibody_header);

        /*
         * We need to subtract another sizeof(__u32) since an in-inode xattr
         * needs an empty 4 bytes to indicate the gap between the xattr entry
         * and the name/value pair.
         */
        if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
                return EXT4_XATTR_SIZE(min_offs -
                        EXT4_XATTR_LEN(strlen(EXT4_XATTR_SYSTEM_DATA)) -
                        EXT4_XATTR_ROUND - sizeof(__u32));

        raw_inode = ext4_raw_inode(iloc);
        header = IHDR(inode, raw_inode);
        entry = IFIRST(header);

        /* Compute min_offs. */
        for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
                if (!entry->e_value_inum && entry->e_value_size) {
                        size_t offs = le16_to_cpu(entry->e_value_offs);
                        if (offs < min_offs)
                                min_offs = offs;
                }
        }
        free = min_offs -
                ((void *)entry - (void *)IFIRST(header)) - sizeof(__u32);

        if (EXT4_I(inode)->i_inline_off) {
                entry = (struct ext4_xattr_entry *)
                        ((void *)raw_inode + EXT4_I(inode)->i_inline_off);

                free += EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
                goto out;
        }

        free -= EXT4_XATTR_LEN(strlen(EXT4_XATTR_SYSTEM_DATA));

        if (free > EXT4_XATTR_ROUND)
                free = EXT4_XATTR_SIZE(free - EXT4_XATTR_ROUND);
        else
                free = 0;

out:
        return free;
}

/*
 * Get the maximum size we now can store in an inode.
 * If we can't find the space for a xattr entry, don't use the space
 * of the extents since we have no space to indicate the inline data.
 */
int ext4_get_max_inline_size(struct inode *inode)
{
        int error, max_inline_size;
        struct ext4_iloc iloc;

        if (EXT4_I(inode)->i_extra_isize == 0)
                return 0;

        error = ext4_get_inode_loc(inode, &iloc);
        if (error) {
                ext4_error_inode(inode, __func__, __LINE__, 0,
                                 "can't get inode location %lu",
                                 inode->i_ino);
                return 0;
        }

        down_read(&EXT4_I(inode)->xattr_sem);
        max_inline_size = get_max_inline_xattr_value_size(inode, &iloc);
        up_read(&EXT4_I(inode)->xattr_sem);

        brelse(iloc.bh);

        if (!max_inline_size)
                return 0;

        return max_inline_size + EXT4_MIN_INLINE_DATA_SIZE;
}

/*
 * this function does not take xattr_sem, which is OK because it is
 * currently only used in a code path coming form ext4_iget, before
 * the new inode has been unlocked
 */
int ext4_find_inline_data_nolock(struct inode *inode)
{
        struct ext4_xattr_ibody_find is = {
                .s = { .not_found = -ENODATA, },
        };
        struct ext4_xattr_info i = {
                .name_index = EXT4_XATTR_INDEX_SYSTEM,
                .name = EXT4_XATTR_SYSTEM_DATA,
        };
        int error;

        if (EXT4_I(inode)->i_extra_isize == 0)
                return 0;

        error = ext4_get_inode_loc(inode, &is.iloc);
        if (error)
                return error;

        error = ext4_xattr_ibody_find(inode, &i, &is);
        if (error)
                goto out;

        if (!is.s.not_found) {
                if (is.s.here->e_value_inum) {
                        EXT4_ERROR_INODE(inode, "inline data xattr refers "
                                         "to an external xattr inode");
                        error = -EFSCORRUPTED;
                        goto out;
                }
                EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
                                        (void *)ext4_raw_inode(&is.iloc));
                EXT4_I(inode)->i_inline_size = EXT4_MIN_INLINE_DATA_SIZE +
                                le32_to_cpu(is.s.here->e_value_size);
                ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
        }
out:
        brelse(is.iloc.bh);
        return error;
}

static int ext4_read_inline_data(struct inode *inode, void *buffer,
                                 unsigned int len,
                                 struct ext4_iloc *iloc)
{
        struct ext4_xattr_entry *entry;
        struct ext4_xattr_ibody_header *header;
        int cp_len = 0;
        struct ext4_inode *raw_inode;

        if (!len)
                return 0;

        BUG_ON(len > EXT4_I(inode)->i_inline_size);

        cp_len = len < EXT4_MIN_INLINE_DATA_SIZE ?
                        len : EXT4_MIN_INLINE_DATA_SIZE;

        raw_inode = ext4_raw_inode(iloc);
        memcpy(buffer, (void *)(raw_inode->i_block), cp_len);

        len -= cp_len;
        buffer += cp_len;

        if (!len)
                goto out;

        header = IHDR(inode, raw_inode);
        entry = (struct ext4_xattr_entry *)((void *)raw_inode +
                                            EXT4_I(inode)->i_inline_off);
        len = min_t(unsigned int, len,
                    (unsigned int)le32_to_cpu(entry->e_value_size));

        memcpy(buffer,
               (void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs), len);
        cp_len += len;

out:
        return cp_len;
}

/*
 * write the buffer to the inline inode.
 * If 'create' is set, we don't need to do the extra copy in the xattr
 * value since it is already handled by ext4_xattr_ibody_inline_set.
 * That saves us one memcpy.
 */
static void ext4_write_inline_data(struct inode *inode, struct ext4_iloc *iloc,
                                   void *buffer, loff_t pos, unsigned int len)
{
        struct ext4_xattr_entry *entry;
        struct ext4_xattr_ibody_header *header;
        struct ext4_inode *raw_inode;
        int cp_len = 0;

        if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
                return;

        BUG_ON(!EXT4_I(inode)->i_inline_off);
        BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);

        raw_inode = ext4_raw_inode(iloc);
        buffer += pos;

        if (pos < EXT4_MIN_INLINE_DATA_SIZE) {
                cp_len = pos + len > EXT4_MIN_INLINE_DATA_SIZE ?
                         EXT4_MIN_INLINE_DATA_SIZE - pos : len;
                memcpy((void *)raw_inode->i_block + pos, buffer, cp_len);

                len -= cp_len;
                buffer += cp_len;
                pos += cp_len;
        }

        if (!len)
                return;

        pos -= EXT4_MIN_INLINE_DATA_SIZE;
        header = IHDR(inode, raw_inode);
        entry = (struct ext4_xattr_entry *)((void *)raw_inode +
                                            EXT4_I(inode)->i_inline_off);

        memcpy((void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs) + pos,
               buffer, len);
}

static int ext4_create_inline_data(handle_t *handle,
                                   struct inode *inode, unsigned len)
{
        int error;
        void *value = NULL;
        struct ext4_xattr_ibody_find is = {
                .s = { .not_found = -ENODATA, },
        };
        struct ext4_xattr_info i = {
                .name_index = EXT4_XATTR_INDEX_SYSTEM,
                .name = EXT4_XATTR_SYSTEM_DATA,
        };

        error = ext4_get_inode_loc(inode, &is.iloc);
        if (error)
                return error;

        BUFFER_TRACE(is.iloc.bh, "get_write_access");
        error = ext4_journal_get_write_access(handle, is.iloc.bh);
        if (error)
                goto out;

        if (len > EXT4_MIN_INLINE_DATA_SIZE) {
                value = EXT4_ZERO_XATTR_VALUE;
                len -= EXT4_MIN_INLINE_DATA_SIZE;
        } else {
                value = "";
                len = 0;
        }

        /* Insert the the xttr entry. */
        i.value = value;
        i.value_len = len;

        error = ext4_xattr_ibody_find(inode, &i, &is);
        if (error)
                goto out;

        BUG_ON(!is.s.not_found);

        error = ext4_xattr_ibody_inline_set(handle, inode, &i, &is);
        if (error) {
                if (error == -ENOSPC)
                        ext4_clear_inode_state(inode,
                                               EXT4_STATE_MAY_INLINE_DATA);
                goto out;
        }

        memset((void *)ext4_raw_inode(&is.iloc)->i_block,
                0, EXT4_MIN_INLINE_DATA_SIZE);

        EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
                                      (void *)ext4_raw_inode(&is.iloc));
        EXT4_I(inode)->i_inline_size = len + EXT4_MIN_INLINE_DATA_SIZE;
        ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
        ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA);
        get_bh(is.iloc.bh);
        error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);

out:
        brelse(is.iloc.bh);
        return error;
}

static int ext4_update_inline_data(handle_t *handle, struct inode *inode,
                                   unsigned int len)
{
        int error;
        void *value = NULL;
        struct ext4_xattr_ibody_find is = {
                .s = { .not_found = -ENODATA, },
        };
        struct ext4_xattr_info i = {
                .name_index = EXT4_XATTR_INDEX_SYSTEM,
                .name = EXT4_XATTR_SYSTEM_DATA,
        };

        /* If the old space is ok, write the data directly. */
        if (len <= EXT4_I(inode)->i_inline_size)
                return 0;

        error = ext4_get_inode_loc(inode, &is.iloc);
        if (error)
                return error;

        error = ext4_xattr_ibody_find(inode, &i, &is);
        if (error)
                goto out;

        BUG_ON(is.s.not_found);

        len -= EXT4_MIN_INLINE_DATA_SIZE;
        value = kzalloc(len, GFP_NOFS);
        if (!value) {
                error = -ENOMEM;
                goto out;
        }

        error = ext4_xattr_ibody_get(inode, i.name_index, i.name,
                                     value, len);
        if (error == -ENODATA)
                goto out;

        BUFFER_TRACE(is.iloc.bh, "get_write_access");
        error = ext4_journal_get_write_access(handle, is.iloc.bh);
        if (error)
                goto out;

        /* Update the xttr entry. */
        i.value = value;
        i.value_len = len;

        error = ext4_xattr_ibody_inline_set(handle, inode, &i, &is);
        if (error)
                goto out;

        EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
                                      (void *)ext4_raw_inode(&is.iloc));
        EXT4_I(inode)->i_inline_size = EXT4_MIN_INLINE_DATA_SIZE +
                                le32_to_cpu(is.s.here->e_value_size);
        ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
        get_bh(is.iloc.bh);
        error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);

out:
        kfree(value);
        brelse(is.iloc.bh);
        return error;
}

static int ext4_prepare_inline_data(handle_t *handle, struct inode *inode,
                                    unsigned int len)
{
        int ret, size, no_expand;
        struct ext4_inode_info *ei = EXT4_I(inode);

        if (!ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))
                return -ENOSPC;

        size = ext4_get_max_inline_size(inode);
        if (size < len)
                return -ENOSPC;

        ext4_write_lock_xattr(inode, &no_expand);

        if (ei->i_inline_off)
                ret = ext4_update_inline_data(handle, inode, len);
        else
                ret = ext4_create_inline_data(handle, inode, len);

        ext4_write_unlock_xattr(inode, &no_expand);
        return ret;
}

static int ext4_destroy_inline_data_nolock(handle_t *handle,
                                           struct inode *inode)
{
        struct ext4_inode_info *ei = EXT4_I(inode);
        struct ext4_xattr_ibody_find is = {
                .s = { .not_found = 0, },
        };
        struct ext4_xattr_info i = {
                .name_index = EXT4_XATTR_INDEX_SYSTEM,
                .name = EXT4_XATTR_SYSTEM_DATA,
                .value = NULL,
                .value_len = 0,
        };
        int error;

        if (!ei->i_inline_off)
                return 0;

        error = ext4_get_inode_loc(inode, &is.iloc);
        if (error)
                return error;

        error = ext4_xattr_ibody_find(inode, &i, &is);
        if (error)
                goto out;

        BUFFER_TRACE(is.iloc.bh, "get_write_access");
        error = ext4_journal_get_write_access(handle, is.iloc.bh);
        if (error)
                goto out;

        error = ext4_xattr_ibody_inline_set(handle, inode, &i, &is);
        if (error)
                goto out;

        memset((void *)ext4_raw_inode(&is.iloc)->i_block,
                0, EXT4_MIN_INLINE_DATA_SIZE);
        memset(ei->i_data, 0, EXT4_MIN_INLINE_DATA_SIZE);

        if (ext4_has_feature_extents(inode->i_sb)) {
                if (S_ISDIR(inode->i_mode) ||
                    S_ISREG(inode->i_mode) || S_ISLNK(inode->i_mode)) {
                        ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
                        ext4_ext_tree_init(handle, inode);
                }
        }
        ext4_clear_inode_flag(inode, EXT4_INODE_INLINE_DATA);

        get_bh(is.iloc.bh);
        error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);

        EXT4_I(inode)->i_inline_off = 0;
        EXT4_I(inode)->i_inline_size = 0;
        ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
out:
        brelse(is.iloc.bh);
        if (error == -ENODATA)
                error = 0;
        return error;
}

static int ext4_read_inline_page(struct inode *inode, struct page *page)
{
        void *kaddr;
        int ret = 0;
        size_t len;
        struct ext4_iloc iloc;

        BUG_ON(!PageLocked(page));
        BUG_ON(!ext4_has_inline_data(inode));
        BUG_ON(page->index);

        if (!EXT4_I(inode)->i_inline_off) {
                ext4_warning(inode->i_sb, "inode %lu doesn't have inline data.",
                             inode->i_ino);
                goto out;
        }

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret)
                goto out;

        len = min_t(size_t, ext4_get_inline_size(inode), i_size_read(inode));
        kaddr = kmap_atomic(page);
        ret = ext4_read_inline_data(inode, kaddr, len, &iloc);
        flush_dcache_page(page);
        kunmap_atomic(kaddr);
        zero_user_segment(page, len, PAGE_SIZE);
        SetPageUptodate(page);
        brelse(iloc.bh);

out:
        return ret;
}

int ext4_readpage_inline(struct inode *inode, struct page *page)
{
        int ret = 0;

        down_read(&EXT4_I(inode)->xattr_sem);
        if (!ext4_has_inline_data(inode)) {
                up_read(&EXT4_I(inode)->xattr_sem);
                return -EAGAIN;
        }

        /*
         * Current inline data can only exist in the 1st page,
         * So for all the other pages, just set them uptodate.
         */
        if (!page->index)
                ret = ext4_read_inline_page(inode, page);
        else if (!PageUptodate(page)) {
                zero_user_segment(page, 0, PAGE_SIZE);
                SetPageUptodate(page);
        }

        up_read(&EXT4_I(inode)->xattr_sem);

        unlock_page(page);
        return ret >= 0 ? 0 : ret;
}

static int ext4_convert_inline_data_to_extent(struct address_space *mapping,
                                              struct inode *inode,
                                              unsigned flags)
{
        int ret, needed_blocks, no_expand;
        handle_t *handle = NULL;
        int retries = 0, sem_held = 0;
        struct page *page = NULL;
        unsigned from, to;
        struct ext4_iloc iloc;

        if (!ext4_has_inline_data(inode)) {
                /*
                 * clear the flag so that no new write
                 * will trap here again.
                 */
                ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
                return 0;
        }

        needed_blocks = ext4_writepage_trans_blocks(inode);

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret)
                return ret;

retry:
        handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
                handle = NULL;
                goto out;
        }

        /* We cannot recurse into the filesystem as the transaction is already
         * started */
        flags |= AOP_FLAG_NOFS;

        page = grab_cache_page_write_begin(mapping, 0, flags);
        if (!page) {
                ret = -ENOMEM;
                goto out;
        }

        ext4_write_lock_xattr(inode, &no_expand);
        sem_held = 1;
        /* If some one has already done this for us, just exit. */
        if (!ext4_has_inline_data(inode)) {
                ret = 0;
                goto out;
        }

        from = 0;
        to = ext4_get_inline_size(inode);
        if (!PageUptodate(page)) {
                ret = ext4_read_inline_page(inode, page);
                if (ret < 0)
                        goto out;
        }

        ret = ext4_destroy_inline_data_nolock(handle, inode);
        if (ret)
                goto out;

        if (ext4_should_dioread_nolock(inode)) {
                ret = __block_write_begin(page, from, to,
                                          ext4_get_block_unwritten);
        } else
                ret = __block_write_begin(page, from, to, ext4_get_block);

        if (!ret && ext4_should_journal_data(inode)) {
                ret = ext4_walk_page_buffers(handle, page_buffers(page),
                                             from, to, NULL,
                                             do_journal_get_write_access);
        }

        if (ret) {
                unlock_page(page);
                put_page(page);
                page = NULL;
                ext4_orphan_add(handle, inode);
                ext4_write_unlock_xattr(inode, &no_expand);
                sem_held = 0;
                ext4_journal_stop(handle);
                handle = NULL;
                ext4_truncate_failed_write(inode);
                /*
                 * If truncate failed early the inode might
                 * still be on the orphan list; we need to
                 * make sure the inode is removed from the
                 * orphan list in that case.
                 */
                if (inode->i_nlink)
                        ext4_orphan_del(NULL, inode);
        }

        if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
                goto retry;

        if (page)
                block_commit_write(page, from, to);
out:
        if (page) {
                unlock_page(page);
                put_page(page);
        }
        if (sem_held)
                ext4_write_unlock_xattr(inode, &no_expand);
        if (handle)
                ext4_journal_stop(handle);
        brelse(iloc.bh);
        return ret;
}

/*
 * Try to write data in the inode.
 * If the inode has inline data, check whether the new write can be
 * in the inode also. If not, create the page the handle, move the data
 * to the page make it update and let the later codes create extent for it.
 */
int ext4_try_to_write_inline_data(struct address_space *mapping,
                                  struct inode *inode,
                                  loff_t pos, unsigned len,
                                  unsigned flags,
                                  struct page **pagep)
{
        int ret;
        handle_t *handle;
        struct page *page;
        struct ext4_iloc iloc;

        if (pos + len > ext4_get_max_inline_size(inode))
                goto convert;

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret)
                return ret;

        /*
         * The possible write could happen in the inode,
         * so try to reserve the space in inode first.
         */
        handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
                handle = NULL;
                goto out;
        }

        ret = ext4_prepare_inline_data(handle, inode, pos + len);
        if (ret && ret != -ENOSPC)
                goto out;

        /* We don't have space in inline inode, so convert it to extent. */
        if (ret == -ENOSPC) {
                ext4_journal_stop(handle);
                brelse(iloc.bh);
                goto convert;
        }

        ret = ext4_journal_get_write_access(handle, iloc.bh);
        if (ret)
                goto out;

        flags |= AOP_FLAG_NOFS;

        page = grab_cache_page_write_begin(mapping, 0, flags);
        if (!page) {
                ret = -ENOMEM;
                goto out;
        }

        *pagep = page;
        down_read(&EXT4_I(inode)->xattr_sem);
        if (!ext4_has_inline_data(inode)) {
                ret = 0;
                unlock_page(page);
                put_page(page);
                goto out_up_read;
        }

        if (!PageUptodate(page)) {
                ret = ext4_read_inline_page(inode, page);
                if (ret < 0) {
                        unlock_page(page);
                        put_page(page);
                        goto out_up_read;
                }
        }

        ret = 1;
        handle = NULL;
out_up_read:
        up_read(&EXT4_I(inode)->xattr_sem);
out:
        if (handle && (ret != 1))
                ext4_journal_stop(handle);
        brelse(iloc.bh);
        return ret;
convert:
        return ext4_convert_inline_data_to_extent(mapping,
                                                  inode, flags);
}

int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len,
                               unsigned copied, struct page *page)
{
        int ret, no_expand;
        void *kaddr;
        struct ext4_iloc iloc;

        if (unlikely(copied < len)) {
                if (!PageUptodate(page)) {
                        copied = 0;
                        goto out;
                }
        }

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret) {
                ext4_std_error(inode->i_sb, ret);
                copied = 0;
                goto out;
        }

        ext4_write_lock_xattr(inode, &no_expand);
        BUG_ON(!ext4_has_inline_data(inode));

        kaddr = kmap_atomic(page);
        ext4_write_inline_data(inode, &iloc, kaddr, pos, len);
        kunmap_atomic(kaddr);
        SetPageUptodate(page);
        /* clear page dirty so that writepages wouldn't work for us. */
        ClearPageDirty(page);

        ext4_write_unlock_xattr(inode, &no_expand);
        brelse(iloc.bh);
        mark_inode_dirty(inode);
out:
        return copied;
}

struct buffer_head *
ext4_journalled_write_inline_data(struct inode *inode,
                                  unsigned len,
                                  struct page *page)
{
        int ret, no_expand;
        void *kaddr;
        struct ext4_iloc iloc;

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret) {
                ext4_std_error(inode->i_sb, ret);
                return NULL;
        }

        ext4_write_lock_xattr(inode, &no_expand);
        kaddr = kmap_atomic(page);
        ext4_write_inline_data(inode, &iloc, kaddr, 0, len);
        kunmap_atomic(kaddr);
        ext4_write_unlock_xattr(inode, &no_expand);

        return iloc.bh;
}

/*
 * Try to make the page cache and handle ready for the inline data case.
 * We can call this function in 2 cases:
 * 1. The inode is created and the first write exceeds inline size. We can
 *    clear the inode state safely.
 * 2. The inode has inline data, then we need to read the data, make it
 *    update and dirty so that ext4_da_writepages can handle it. We don't
 *    need to start the journal since the file's metatdata isn't changed now.
 */
static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
                                                 struct inode *inode,
                                                 unsigned flags,
                                                 void **fsdata)
{
        int ret = 0, inline_size;
        struct page *page;

        page = grab_cache_page_write_begin(mapping, 0, flags);
        if (!page)
                return -ENOMEM;

        down_read(&EXT4_I(inode)->xattr_sem);
        if (!ext4_has_inline_data(inode)) {
                ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
                goto out;
        }

        inline_size = ext4_get_inline_size(inode);

        if (!PageUptodate(page)) {
                ret = ext4_read_inline_page(inode, page);
                if (ret < 0)
                        goto out;
        }

        ret = __block_write_begin(page, 0, inline_size,
                                  ext4_da_get_block_prep);
        if (ret) {
                up_read(&EXT4_I(inode)->xattr_sem);
                unlock_page(page);
                put_page(page);
                ext4_truncate_failed_write(inode);
                return ret;
        }

        SetPageDirty(page);
        SetPageUptodate(page);
        ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
        *fsdata = (void *)CONVERT_INLINE_DATA;

out:
        up_read(&EXT4_I(inode)->xattr_sem);
        if (page) {
                unlock_page(page);
                put_page(page);
        }
        return ret;
}

/*
 * Prepare the write for the inline data.
 * If the the data can be written into the inode, we just read
 * the page and make it uptodate, and start the journal.
 * Otherwise read the page, makes it dirty so that it can be
 * handle in writepages(the i_disksize update is left to the
 * normal ext4_da_write_end).
 */
int ext4_da_write_inline_data_begin(struct address_space *mapping,
                                    struct inode *inode,
                                    loff_t pos, unsigned len,
                                    unsigned flags,
                                    struct page **pagep,
                                    void **fsdata)
{
        int ret, inline_size;
        handle_t *handle;
        struct page *page;
        struct ext4_iloc iloc;
        int retries = 0;

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret)
                return ret;

retry_journal:
        handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
                goto out;
        }

        inline_size = ext4_get_max_inline_size(inode);

        ret = -ENOSPC;
        if (inline_size >= pos + len) {
                ret = ext4_prepare_inline_data(handle, inode, pos + len);
                if (ret && ret != -ENOSPC)
                        goto out_journal;
        }

        /*
         * We cannot recurse into the filesystem as the transaction
         * is already started.
         */
        flags |= AOP_FLAG_NOFS;

        if (ret == -ENOSPC) {
                ext4_journal_stop(handle);
                ret = ext4_da_convert_inline_data_to_extent(mapping,
                                                            inode,
                                                            flags,
                                                            fsdata);
                if (ret == -ENOSPC &&
                    ext4_should_retry_alloc(inode->i_sb, &retries))
                        goto retry_journal;
                goto out;
        }

        page = grab_cache_page_write_begin(mapping, 0, flags);
        if (!page) {
                ret = -ENOMEM;
                goto out_journal;
        }

        down_read(&EXT4_I(inode)->xattr_sem);
        if (!ext4_has_inline_data(inode)) {
                ret = 0;
                goto out_release_page;
        }

        if (!PageUptodate(page)) {
                ret = ext4_read_inline_page(inode, page);
                if (ret < 0)
                        goto out_release_page;
        }
        ret = ext4_journal_get_write_access(handle, iloc.bh);
        if (ret)
                goto out_release_page;

        up_read(&EXT4_I(inode)->xattr_sem);
        *pagep = page;
        brelse(iloc.bh);
        return 1;
out_release_page:
        up_read(&EXT4_I(inode)->xattr_sem);
        unlock_page(page);
        put_page(page);
out_journal:
        ext4_journal_stop(handle);
out:
        brelse(iloc.bh);
        return ret;
}

int ext4_da_write_inline_data_end(struct inode *inode, loff_t pos,
                                  unsigned len, unsigned copied,
                                  struct page *page)
{
        int ret;

        ret = ext4_write_inline_data_end(inode, pos, len, copied, page);
        if (ret < 0) {
                unlock_page(page);
                put_page(page);
                return ret;
        }
        copied = ret;

        /*
         * No need to use i_size_read() here, the i_size
         * cannot change under us because we hold i_mutex.
         *
         * But it's important to update i_size while still holding page lock:
         * page writeout could otherwise come in and zero beyond i_size.
         */
        if (pos+copied > inode->i_size)
                i_size_write(inode, pos+copied);
        unlock_page(page);
        put_page(page);

        /*
         * Don't mark the inode dirty under page lock. First, it unnecessarily
         * makes the holding time of page lock longer. Second, it forces lock
         * ordering of page lock and transaction start for journaling
         * filesystems.
         */
        mark_inode_dirty(inode);

        return copied;
}

#ifdef INLINE_DIR_DEBUG
void ext4_show_inline_dir(struct inode *dir, struct buffer_head *bh,
                          void *inline_start, int inline_size)
{
        int offset;
        unsigned short de_len;
        struct ext4_dir_entry_2 *de = inline_start;
        void *dlimit = inline_start + inline_size;

        trace_printk("inode %lu\n", dir->i_ino);
        offset = 0;
        while ((void *)de < dlimit) {
                de_len = ext4_rec_len_from_disk(de->rec_len, inline_size);
                trace_printk("de: off %u rlen %u name %.*s nlen %u ino %u\n",
                             offset, de_len, de->name_len, de->name,
                             de->name_len, le32_to_cpu(de->inode));
                if (ext4_check_dir_entry(dir, NULL, de, bh,
                                         inline_start, inline_size, offset))
                        BUG();

                offset += de_len;
                de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
        }
}
#else
#define ext4_show_inline_dir(dir, bh, inline_start, inline_size)
#endif

/*
 * Add a new entry into a inline dir.
 * It will return -ENOSPC if no space is available, and -EIO
 * and -EEXIST if directory entry already exists.
 */
static int ext4_add_dirent_to_inline(handle_t *handle,
                                     struct ext4_filename *fname,
                                     struct inode *dir,
                                     struct inode *inode,
                                     struct ext4_iloc *iloc,
                                     void *inline_start, int inline_size)
{
        int             err;
        struct ext4_dir_entry_2 *de;

        err = ext4_find_dest_de(dir, inode, iloc->bh, inline_start,
                                inline_size, fname, &de);
        if (err)
                return err;

        BUFFER_TRACE(iloc->bh, "get_write_access");
        err = ext4_journal_get_write_access(handle, iloc->bh);
        if (err)
                return err;
        ext4_insert_dentry(inode, de, inline_size, fname);

        ext4_show_inline_dir(dir, iloc->bh, inline_start, inline_size);

        /*
         * XXX shouldn't update any times until successful
         * completion of syscall, but too many callers depend
         * on this.
         *
         * XXX similarly, too many callers depend on
         * ext4_new_inode() setting the times, but error
         * recovery deletes the inode, so the worst that can
         * happen is that the times are slightly out of date
         * and/or different from the directory change time.
         */
        dir->i_mtime = dir->i_ctime = current_time(dir);
        ext4_update_dx_flag(dir);
        inode_inc_iversion(dir);
        return 1;
}

static void *ext4_get_inline_xattr_pos(struct inode *inode,
                                       struct ext4_iloc *iloc)
{
        struct ext4_xattr_entry *entry;
        struct ext4_xattr_ibody_header *header;

        BUG_ON(!EXT4_I(inode)->i_inline_off);

        header = IHDR(inode, ext4_raw_inode(iloc));
        entry = (struct ext4_xattr_entry *)((void *)ext4_raw_inode(iloc) +
                                            EXT4_I(inode)->i_inline_off);

        return (void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs);
}

/* Set the final de to cover the whole block. */
static void ext4_update_final_de(void *de_buf, int old_size, int new_size)
{
        struct ext4_dir_entry_2 *de, *prev_de;
        void *limit;
        int de_len;

        de = (struct ext4_dir_entry_2 *)de_buf;
        if (old_size) {
                limit = de_buf + old_size;
                do {
                        prev_de = de;
                        de_len = ext4_rec_len_from_disk(de->rec_len, old_size);
                        de_buf += de_len;
                        de = (struct ext4_dir_entry_2 *)de_buf;
                } while (de_buf < limit);

                prev_de->rec_len = ext4_rec_len_to_disk(de_len + new_size -
                                                        old_size, new_size);
        } else {
                /* this is just created, so create an empty entry. */
                de->inode = 0;
                de->rec_len = ext4_rec_len_to_disk(new_size, new_size);
        }
}

static int ext4_update_inline_dir(handle_t *handle, struct inode *dir,
                                  struct ext4_iloc *iloc)
{
        int ret;
        int old_size = EXT4_I(dir)->i_inline_size - EXT4_MIN_INLINE_DATA_SIZE;
        int new_size = get_max_inline_xattr_value_size(dir, iloc);

        if (new_size - old_size <= EXT4_DIR_REC_LEN(1))
                return -ENOSPC;

        ret = ext4_update_inline_data(handle, dir,
                                      new_size + EXT4_MIN_INLINE_DATA_SIZE);
        if (ret)
                return ret;

        ext4_update_final_de(ext4_get_inline_xattr_pos(dir, iloc), old_size,
                             EXT4_I(dir)->i_inline_size -
                                                EXT4_MIN_INLINE_DATA_SIZE);
        dir->i_size = EXT4_I(dir)->i_disksize = EXT4_I(dir)->i_inline_size;
        return 0;
}

static void ext4_restore_inline_data(handle_t *handle, struct inode *inode,
                                     struct ext4_iloc *iloc,
                                     void *buf, int inline_size)
{
        ext4_create_inline_data(handle, inode, inline_size);
        ext4_write_inline_data(inode, iloc, buf, 0, inline_size);
        ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
}

static int ext4_finish_convert_inline_dir(handle_t *handle,
                                          struct inode *inode,
                                          struct buffer_head *dir_block,
                                          void *buf,
                                          int inline_size)
{
        int err, csum_size = 0, header_size = 0;
        struct ext4_dir_entry_2 *de;
        void *target = dir_block->b_data;

        /*
         * First create "." and ".." and then copy the dir information
         * back to the block.
         */
        de = (struct ext4_dir_entry_2 *)target;
        de = ext4_init_dot_dotdot(inode, de,
                inode->i_sb->s_blocksize, csum_size,
                le32_to_cpu(((struct ext4_dir_entry_2 *)buf)->inode), 1);
        header_size = (void *)de - target;

        memcpy((void *)de, buf + EXT4_INLINE_DOTDOT_SIZE,
                inline_size - EXT4_INLINE_DOTDOT_SIZE);

        if (ext4_has_metadata_csum(inode->i_sb))
                csum_size = sizeof(struct ext4_dir_entry_tail);

        inode->i_size = inode->i_sb->s_blocksize;
        i_size_write(inode, inode->i_sb->s_blocksize);
        EXT4_I(inode)->i_disksize = inode->i_sb->s_blocksize;
        ext4_update_final_de(dir_block->b_data,
                        inline_size - EXT4_INLINE_DOTDOT_SIZE + header_size,
                        inode->i_sb->s_blocksize - csum_size);

        if (csum_size)
                ext4_initialize_dirent_tail(dir_block,
                                            inode->i_sb->s_blocksize);
        set_buffer_uptodate(dir_block);
        err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
        if (err)
                return err;
        set_buffer_verified(dir_block);
        return ext4_mark_inode_dirty(handle, inode);
}

static int ext4_convert_inline_data_nolock(handle_t *handle,
                                           struct inode *inode,
                                           struct ext4_iloc *iloc)
{
        int error;
        void *buf = NULL;
        struct buffer_head *data_bh = NULL;
        struct ext4_map_blocks map;
        int inline_size;

        inline_size = ext4_get_inline_size(inode);
        buf = kmalloc(inline_size, GFP_NOFS);
        if (!buf) {
                error = -ENOMEM;
                goto out;
        }

        error = ext4_read_inline_data(inode, buf, inline_size, iloc);
        if (error < 0)
                goto out;

        /*
         * Make sure the inline directory entries pass checks before we try to
         * convert them, so that we avoid touching stuff that needs fsck.
         */
        if (S_ISDIR(inode->i_mode)) {
                error = ext4_check_all_de(inode, iloc->bh,
                                        buf + EXT4_INLINE_DOTDOT_SIZE,
                                        inline_size - EXT4_INLINE_DOTDOT_SIZE);
                if (error)
                        goto out;
        }

        error = ext4_destroy_inline_data_nolock(handle, inode);
        if (error)
                goto out;

        map.m_lblk = 0;
        map.m_len = 1;
        map.m_flags = 0;
        error = ext4_map_blocks(handle, inode, &map, EXT4_GET_BLOCKS_CREATE);
        if (error < 0)
                goto out_restore;
        if (!(map.m_flags & EXT4_MAP_MAPPED)) {
                error = -EIO;
                goto out_restore;
        }

        data_bh = sb_getblk(inode->i_sb, map.m_pblk);
        if (!data_bh) {
                error = -ENOMEM;
                goto out_restore;
        }

        lock_buffer(data_bh);
        error = ext4_journal_get_create_access(handle, data_bh);
        if (error) {
                unlock_buffer(data_bh);
                error = -EIO;
                goto out_restore;
        }
        memset(data_bh->b_data, 0, inode->i_sb->s_blocksize);

        if (!S_ISDIR(inode->i_mode)) {
                memcpy(data_bh->b_data, buf, inline_size);
                set_buffer_uptodate(data_bh);
                error = ext4_handle_dirty_metadata(handle,
                                                   inode, data_bh);
        } else {
                error = ext4_finish_convert_inline_dir(handle, inode, data_bh,
                                                       buf, inline_size);
        }

        unlock_buffer(data_bh);
out_restore:
        if (error)
                ext4_restore_inline_data(handle, inode, iloc, buf, inline_size);

out:
        brelse(data_bh);
        kfree(buf);
        return error;
}

/*
 * Try to add the new entry to the inline data.
 * If succeeds, return 0. If not, extended the inline dir and copied data to
 * the new created block.
 */
int ext4_try_add_inline_entry(handle_t *handle, struct ext4_filename *fname,
                              struct inode *dir, struct inode *inode)
{
        int ret, inline_size, no_expand;
        void *inline_start;
        struct ext4_iloc iloc;

        ret = ext4_get_inode_loc(dir, &iloc);
        if (ret)
                return ret;

        ext4_write_lock_xattr(dir, &no_expand);
        if (!ext4_has_inline_data(dir))
                goto out;

        inline_start = (void *)ext4_raw_inode(&iloc)->i_block +
                                                 EXT4_INLINE_DOTDOT_SIZE;
        inline_size = EXT4_MIN_INLINE_DATA_SIZE - EXT4_INLINE_DOTDOT_SIZE;

        ret = ext4_add_dirent_to_inline(handle, fname, dir, inode, &iloc,
                                        inline_start, inline_size);
        if (ret != -ENOSPC)
                goto out;

        /* check whether it can be inserted to inline xattr space. */
        inline_size = EXT4_I(dir)->i_inline_size -
                        EXT4_MIN_INLINE_DATA_SIZE;
        if (!inline_size) {
                /* Try to use the xattr space.*/
                ret = ext4_update_inline_dir(handle, dir, &iloc);
                if (ret && ret != -ENOSPC)
                        goto out;

                inline_size = EXT4_I(dir)->i_inline_size -
                                EXT4_MIN_INLINE_DATA_SIZE;
        }

        if (inline_size) {
                inline_start = ext4_get_inline_xattr_pos(dir, &iloc);

                ret = ext4_add_dirent_to_inline(handle, fname, dir,
                                                inode, &iloc, inline_start,
                                                inline_size);

                if (ret != -ENOSPC)
                        goto out;
        }

        /*
         * The inline space is filled up, so create a new block for it.
         * As the extent tree will be created, we have to save the inline
         * dir first.
         */
        ret = ext4_convert_inline_data_nolock(handle, dir, &iloc);

out:
        ext4_write_unlock_xattr(dir, &no_expand);
        ext4_mark_inode_dirty(handle, dir);
        brelse(iloc.bh);
        return ret;
}

/*
 * This function fills a red-black tree with information from an
 * inlined dir.  It returns the number directory entries loaded
 * into the tree.  If there is an error it is returned in err.
 */
int ext4_inlinedir_to_tree(struct file *dir_file,
                           struct inode *dir, ext4_lblk_t block,
                           struct dx_hash_info *hinfo,
                           __u32 start_hash, __u32 start_minor_hash,
                           int *has_inline_data)
{
        int err = 0, count = 0;
        unsigned int parent_ino;
        int pos;
        struct ext4_dir_entry_2 *de;
        struct inode *inode = file_inode(dir_file);
        int ret, inline_size = 0;
        struct ext4_iloc iloc;
        void *dir_buf = NULL;
        struct ext4_dir_entry_2 fake;
        struct fscrypt_str tmp_str;

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret)
                return ret;

        down_read(&EXT4_I(inode)->xattr_sem);
        if (!ext4_has_inline_data(inode)) {
                up_read(&EXT4_I(inode)->xattr_sem);
                *has_inline_data = 0;
                goto out;
        }

        inline_size = ext4_get_inline_size(inode);
        dir_buf = kmalloc(inline_size, GFP_NOFS);
        if (!dir_buf) {
                ret = -ENOMEM;
                up_read(&EXT4_I(inode)->xattr_sem);
                goto out;
        }

        ret = ext4_read_inline_data(inode, dir_buf, inline_size, &iloc);
        up_read(&EXT4_I(inode)->xattr_sem);
        if (ret < 0)
                goto out;

        pos = 0;
        parent_ino = le32_to_cpu(((struct ext4_dir_entry_2 *)dir_buf)->inode);
        while (pos < inline_size) {
                /*
                 * As inlined dir doesn't store any information about '.' and
                 * only the inode number of '..' is stored, we have to handle
                 * them differently.
                 */
                if (pos == 0) {
                        fake.inode = cpu_to_le32(inode->i_ino);
                        fake.name_len = 1;
                        strcpy(fake.name, ".");
                        fake.rec_len = ext4_rec_len_to_disk(
                                                EXT4_DIR_REC_LEN(fake.name_len),
                                                inline_size);
                        ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
                        de = &fake;
                        pos = EXT4_INLINE_DOTDOT_OFFSET;
                } else if (pos == EXT4_INLINE_DOTDOT_OFFSET) {
                        fake.inode = cpu_to_le32(parent_ino);
                        fake.name_len = 2;
                        strcpy(fake.name, "..");
                        fake.rec_len = ext4_rec_len_to_disk(
                                                EXT4_DIR_REC_LEN(fake.name_len),
                                                inline_size);
                        ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
                        de = &fake;
                        pos = EXT4_INLINE_DOTDOT_SIZE;
                } else {
                        de = (struct ext4_dir_entry_2 *)(dir_buf + pos);
                        pos += ext4_rec_len_from_disk(de->rec_len, inline_size);
                        if (ext4_check_dir_entry(inode, dir_file, de,
                                         iloc.bh, dir_buf,
                                         inline_size, pos)) {
                                ret = count;
                                goto out;
                        }
                }

                ext4fs_dirhash(dir, de->name, de->name_len, hinfo);
                if ((hinfo->hash < start_hash) ||
                    ((hinfo->hash == start_hash) &&
                     (hinfo->minor_hash < start_minor_hash)))
                        continue;
                if (de->inode == 0)
                        continue;
                tmp_str.name = de->name;
                tmp_str.len = de->name_len;
                err = ext4_htree_store_dirent(dir_file, hinfo->hash,
                                              hinfo->minor_hash, de, &tmp_str);
                if (err) {
                        count = err;
                        goto out;
                }
                count++;
        }
        ret = count;
out:
        kfree(dir_buf);
        brelse(iloc.bh);
        return ret;
}

/*
 * So this function is called when the volume is mkfsed with
 * dir_index disabled. In order to keep f_pos persistent
 * after we convert from an inlined dir to a blocked based,
 * we just pretend that we are a normal dir and return the
 * offset as if '.' and '..' really take place.
 *
 */
int ext4_read_inline_dir(struct file *file,
                         struct dir_context *ctx,
                         int *has_inline_data)
{
        unsigned int offset, parent_ino;
        int i;
        struct ext4_dir_entry_2 *de;
        struct super_block *sb;
        struct inode *inode = file_inode(file);
        int ret, inline_size = 0;
        struct ext4_iloc iloc;
        void *dir_buf = NULL;
        int dotdot_offset, dotdot_size, extra_offset, extra_size;

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret)
                return ret;

        down_read(&EXT4_I(inode)->xattr_sem);
        if (!ext4_has_inline_data(inode)) {
                up_read(&EXT4_I(inode)->xattr_sem);
                *has_inline_data = 0;
                goto out;
        }

        inline_size = ext4_get_inline_size(inode);
        dir_buf = kmalloc(inline_size, GFP_NOFS);
        if (!dir_buf) {
                ret = -ENOMEM;
                up_read(&EXT4_I(inode)->xattr_sem);
                goto out;
        }

        ret = ext4_read_inline_data(inode, dir_buf, inline_size, &iloc);
        up_read(&EXT4_I(inode)->xattr_sem);
        if (ret < 0)
                goto out;

        ret = 0;
        sb = inode->i_sb;
        parent_ino = le32_to_cpu(((struct ext4_dir_entry_2 *)dir_buf)->inode);
        offset = ctx->pos;

        /*
         * dotdot_offset and dotdot_size is the real offset and
         * size for ".." and "." if the dir is block based while
         * the real size for them are only EXT4_INLINE_DOTDOT_SIZE.
         * So we will use extra_offset and extra_size to indicate them
         * during the inline dir iteration.
         */
        dotdot_offset = EXT4_DIR_REC_LEN(1);
        dotdot_size = dotdot_offset + EXT4_DIR_REC_LEN(2);
        extra_offset = dotdot_size - EXT4_INLINE_DOTDOT_SIZE;
        extra_size = extra_offset + inline_size;

        /*
         * If the version 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 inline
         * dir to make sure.
         */
        if (!inode_eq_iversion(inode, file->f_version)) {
                for (i = 0; i < extra_size && i < offset;) {
                        /*
                         * "." is with offset 0 and
                         * ".." is dotdot_offset.
                         */
                        if (!i) {
                                i = dotdot_offset;
                                continue;
                        } else if (i == dotdot_offset) {
                                i = dotdot_size;
                                continue;
                        }
                        /* for other entry, the real offset in
                         * the buf has to be tuned accordingly.
                         */
                        de = (struct ext4_dir_entry_2 *)
                                (dir_buf + i - extra_offset);
                        /* 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 (ext4_rec_len_from_disk(de->rec_len, extra_size)
                                < EXT4_DIR_REC_LEN(1))
                                break;
                        i += ext4_rec_len_from_disk(de->rec_len,
                                                    extra_size);
                }
                offset = i;
                ctx->pos = offset;
                file->f_version = inode_query_iversion(inode);
        }

        while (ctx->pos < extra_size) {
                if (ctx->pos == 0) {
                        if (!dir_emit(ctx, ".", 1, inode->i_ino, DT_DIR))
                                goto out;
                        ctx->pos = dotdot_offset;
                        continue;
                }

                if (ctx->pos == dotdot_offset) {
                        if (!dir_emit(ctx, "..", 2, parent_ino, DT_DIR))
                                goto out;
                        ctx->pos = dotdot_size;
                        continue;
                }

                de = (struct ext4_dir_entry_2 *)
                        (dir_buf + ctx->pos - extra_offset);
                if (ext4_check_dir_entry(inode, file, de, iloc.bh, dir_buf,
                                         extra_size, ctx->pos))
                        goto out;
                if (le32_to_cpu(de->inode)) {
                        if (!dir_emit(ctx, de->name, de->name_len,
                                      le32_to_cpu(de->inode),
                                      get_dtype(sb, de->file_type)))
                                goto out;
                }
                ctx->pos += ext4_rec_len_from_disk(de->rec_len, extra_size);
        }
out:
        kfree(dir_buf);
        brelse(iloc.bh);
        return ret;
}

struct buffer_head *ext4_get_first_inline_block(struct inode *inode,
                                        struct ext4_dir_entry_2 **parent_de,
                                        int *retval)
{
        struct ext4_iloc iloc;

        *retval = ext4_get_inode_loc(inode, &iloc);
        if (*retval)
                return NULL;

        *parent_de = (struct ext4_dir_entry_2 *)ext4_raw_inode(&iloc)->i_block;

        return iloc.bh;
}

/*
 * Try to create the inline data for the new dir.
 * If it succeeds, return 0, otherwise return the error.
 * In case of ENOSPC, the caller should create the normal disk layout dir.
 */
int ext4_try_create_inline_dir(handle_t *handle, struct inode *parent,
                               struct inode *inode)
{
        int ret, inline_size = EXT4_MIN_INLINE_DATA_SIZE;
        struct ext4_iloc iloc;
        struct ext4_dir_entry_2 *de;

        ret = ext4_get_inode_loc(inode, &iloc);
        if (ret)
                return ret;

        ret = ext4_prepare_inline_data(handle, inode, inline_size);
        if (ret)
                goto out;

        /*
         * For inline dir, we only save the inode information for the ".."
         * and create a fake dentry to cover the left space.
         */
        de = (struct ext4_dir_entry_2 *)ext4_raw_inode(&iloc)->i_block;
        de->inode = cpu_to_le32(parent->i_ino);
        de = (struct ext4_dir_entry_2 *)((void *)de + EXT4_INLINE_DOTDOT_SIZE);
        de->inode = 0;
        de->rec_len = ext4_rec_len_to_disk(
                                inline_size - EXT4_INLINE_DOTDOT_SIZE,
                                inline_size);
        set_nlink(inode, 2);
        inode->i_size = EXT4_I(inode)->i_disksize = inline_size;
out:
        brelse(iloc.bh);
        return ret;
}

struct buffer_head *ext4_find_inline_entry(struct inode *dir,
                                        struct ext4_filename *fname,
                                        struct ext4_dir_entry_2 **res_dir,
                                        int *has_inline_data)
{
        int ret;
        struct ext4_iloc iloc;
        void *inline_start;
        int inline_size;

        if (ext4_get_inode_loc(dir, &iloc))
                return NULL;

        down_read(&EXT4_I(dir)->xattr_sem);
        if (!ext4_has_inline_data(dir)) {
                *has_inline_data = 0;
                goto out;
        }

        inline_start = (void *)ext4_raw_inode(&iloc)->i_block +
                                                EXT4_INLINE_DOTDOT_SIZE;
        inline_size = EXT4_MIN_INLINE_DATA_SIZE - EXT4_INLINE_DOTDOT_SIZE;
        ret = ext4_search_dir(iloc.bh, inline_start, inline_size,
                              dir, fname, 0, res_dir);
        if (ret == 1)
                goto out_find;
        if (ret < 0)
                goto out;

        if (ext4_get_inline_size(dir) == EXT4_MIN_INLINE_DATA_SIZE)
                goto out;

        inline_start = ext4_get_inline_xattr_pos(dir, &iloc);
        inline_size = ext4_get_inline_size(dir) - EXT4_MIN_INLINE_DATA_SIZE;

        ret = ext4_search_dir(iloc.bh, inline_start, inline_size,
                              dir, fname, 0, res_dir);
        if (ret == 1)
                goto out_find;

out:
        brelse(iloc.bh);
        iloc.bh = NULL;
out_find:
        up_read(&EXT4_I(dir)->xattr_sem);
        return iloc.bh;
}

int ext4_delete_inline_entry(handle_t *handle,
                             struct inode *dir,
                             struct ext4_dir_entry_2 *de_del,
                             struct buffer_head *bh,
                             int *has_inline_data)
{
        int err, inline_size, no_expand;
        struct ext4_iloc iloc;
        void *inline_start;

        err = ext4_get_inode_loc(dir, &iloc);
        if (err)
                return err;

        ext4_write_lock_xattr(dir, &no_expand);
        if (!ext4_has_inline_data(dir)) {
                *has_inline_data = 0;
                goto out;
        }

        if ((void *)de_del - ((void *)ext4_raw_inode(&iloc)->i_block) <
                EXT4_MIN_INLINE_DATA_SIZE) {
                inline_start = (void *)ext4_raw_inode(&iloc)->i_block +
                                        EXT4_INLINE_DOTDOT_SIZE;
                inline_size = EXT4_MIN_INLINE_DATA_SIZE -
                                EXT4_INLINE_DOTDOT_SIZE;
        } else {
                inline_start = ext4_get_inline_xattr_pos(dir, &iloc);
                inline_size = ext4_get_inline_size(dir) -
                                EXT4_MIN_INLINE_DATA_SIZE;
        }

        BUFFER_TRACE(bh, "get_write_access");
        err = ext4_journal_get_write_access(handle, bh);
        if (err)
                goto out;

        err = ext4_generic_delete_entry(handle, dir, de_del, bh,
                                        inline_start, inline_size, 0);
        if (err)
                goto out;

        ext4_show_inline_dir(dir, iloc.bh, inline_start, inline_size);
out:
        ext4_write_unlock_xattr(dir, &no_expand);
        if (likely(err == 0))
                err = ext4_mark_inode_dirty(handle, dir);
        brelse(iloc.bh);
        if (err != -ENOENT)
                ext4_std_error(dir->i_sb, err);
        return err;
}

/*
 * Get the inline dentry at offset.
 */
static inline struct ext4_dir_entry_2 *
ext4_get_inline_entry(struct inode *inode,
                      struct ext4_iloc *iloc,
                      unsigned int offset,
                      void **inline_start,
                      int *inline_size)
{
        void *inline_pos;

        BUG_ON(offset > ext4_get_inline_size(inode));

        if (offset < EXT4_MIN_INLINE_DATA_SIZE) {
                inline_pos = (void *)ext4_raw_inode(iloc)->i_block;
                *inline_size = EXT4_MIN_INLINE_DATA_SIZE;
        } else {
                inline_pos = ext4_get_inline_xattr_pos(inode, iloc);
                offset -= EXT4_MIN_INLINE_DATA_SIZE;
                *inline_size = ext4_get_inline_size(inode) -
                                EXT4_MIN_INLINE_DATA_SIZE;
        }

        if (inline_start)
                *inline_start = inline_pos;
        return (struct ext4_dir_entry_2 *)(inline_pos + offset);
}

bool empty_inline_dir(struct inode *dir, int *has_inline_data)
{
        int err, inline_size;
        struct ext4_iloc iloc;
        size_t inline_len;
        void *inline_pos;
        unsigned int offset;
        struct ext4_dir_entry_2 *de;
        bool ret = true;

        err = ext4_get_inode_loc(dir, &iloc);
        if (err) {
                EXT4_ERROR_INODE(dir, "error %d getting inode %lu block",
                                 err, dir->i_ino);
                return true;
        }

        down_read(&EXT4_I(dir)->xattr_sem);
        if (!ext4_has_inline_data(dir)) {
                *has_inline_data = 0;
                goto out;
        }

        de = (struct ext4_dir_entry_2 *)ext4_raw_inode(&iloc)->i_block;
        if (!le32_to_cpu(de->inode)) {
                ext4_warning(dir->i_sb,
                             "bad inline directory (dir #%lu) - no `..'",
                             dir->i_ino);
                ret = true;
                goto out;
        }

        inline_len = ext4_get_inline_size(dir);
        offset = EXT4_INLINE_DOTDOT_SIZE;
        while (offset < inline_len) {
                de = ext4_get_inline_entry(dir, &iloc, offset,
                                           &inline_pos, &inline_size);
                if (ext4_check_dir_entry(dir, NULL, de,
                                         iloc.bh, inline_pos,
                                         inline_size, offset)) {
                        ext4_warning(dir->i_sb,
                                     "bad inline directory (dir #%lu) - "
                                     "inode %u, rec_len %u, name_len %d"
                                     "inline size %d",
                                     dir->i_ino, le32_to_cpu(de->inode),
                                     le16_to_cpu(de->rec_len), de->name_len,
                                     inline_size);
                        ret = true;
                        goto out;
                }
                if (le32_to_cpu(de->inode)) {
                        ret = false;
                        goto out;
                }
                offset += ext4_rec_len_from_disk(de->rec_len, inline_size);
        }

out:
        up_read(&EXT4_I(dir)->xattr_sem);
        brelse(iloc.bh);
        return ret;
}

int ext4_destroy_inline_data(handle_t *handle, struct inode *inode)
{
        int ret, no_expand;

        ext4_write_lock_xattr(inode, &no_expand);
        ret = ext4_destroy_inline_data_nolock(handle, inode);
        ext4_write_unlock_xattr(inode, &no_expand);

        return ret;
}

int ext4_inline_data_iomap(struct inode *inode, struct iomap *iomap)
{
        __u64 addr;
        int error = -EAGAIN;
        struct ext4_iloc iloc;

        down_read(&EXT4_I(inode)->xattr_sem);
        if (!ext4_has_inline_data(inode))
                goto out;

        error = ext4_get_inode_loc(inode, &iloc);
        if (error)
                goto out;

        addr = (__u64)iloc.bh->b_blocknr << inode->i_sb->s_blocksize_bits;
        addr += (char *)ext4_raw_inode(&iloc) - iloc.bh->b_data;
        addr += offsetof(struct ext4_inode, i_block);

        brelse(iloc.bh);

        iomap->addr = addr;
        iomap->offset = 0;
        iomap->length = min_t(loff_t, ext4_get_inline_size(inode),
                              i_size_read(inode));
        iomap->type = IOMAP_INLINE;
        iomap->flags = 0;

out:
        up_read(&EXT4_I(inode)->xattr_sem);
        return error;
}

int ext4_inline_data_fiemap(struct inode *inode,
                            struct fiemap_extent_info *fieinfo,
                            int *has_inline, __u64 start, __u64 len)
{
        __u64 physical = 0;
        __u64 inline_len;
        __u32 flags = FIEMAP_EXTENT_DATA_INLINE | FIEMAP_EXTENT_NOT_ALIGNED |
                FIEMAP_EXTENT_LAST;
        int error = 0;
        struct ext4_iloc iloc;

        down_read(&EXT4_I(inode)->xattr_sem);
        if (!ext4_has_inline_data(inode)) {
                *has_inline = 0;
                goto out;
        }
        inline_len = min_t(size_t, ext4_get_inline_size(inode),
                           i_size_read(inode));
        if (start >= inline_len)
                goto out;
        if (start + len < inline_len)
                inline_len = start + len;
        inline_len -= start;

        error = ext4_get_inode_loc(inode, &iloc);
        if (error)
                goto out;

        physical = (__u64)iloc.bh->b_blocknr << inode->i_sb->s_blocksize_bits;
        physical += (char *)ext4_raw_inode(&iloc) - iloc.bh->b_data;
        physical += offsetof(struct ext4_inode, i_block);

        brelse(iloc.bh);
out:
        up_read(&EXT4_I(inode)->xattr_sem);
        if (physical)
                error = fiemap_fill_next_extent(fieinfo, start, physical,
                                                inline_len, flags);
        return (error < 0 ? error : 0);
}

int ext4_inline_data_truncate(struct inode *inode, int *has_inline)
{
        handle_t *handle;
        int inline_size, value_len, needed_blocks, no_expand, err = 0;
        size_t i_size;
        void *value = NULL;
        struct ext4_xattr_ibody_find is = {
                .s = { .not_found = -ENODATA, },
        };
        struct ext4_xattr_info i = {
                .name_index = EXT4_XATTR_INDEX_SYSTEM,
                .name = EXT4_XATTR_SYSTEM_DATA,
        };


        needed_blocks = ext4_writepage_trans_blocks(inode);
        handle = ext4_journal_start(inode, EXT4_HT_INODE, needed_blocks);
        if (IS_ERR(handle))
                return PTR_ERR(handle);

        ext4_write_lock_xattr(inode, &no_expand);
        if (!ext4_has_inline_data(inode)) {
                *has_inline = 0;
                ext4_journal_stop(handle);
                return 0;
        }

        if ((err = ext4_orphan_add(handle, inode)) != 0)
                goto out;

        if ((err = ext4_get_inode_loc(inode, &is.iloc)) != 0)
                goto out;

        down_write(&EXT4_I(inode)->i_data_sem);
        i_size = inode->i_size;
        inline_size = ext4_get_inline_size(inode);
        EXT4_I(inode)->i_disksize = i_size;

        if (i_size < inline_size) {
                /* Clear the content in the xattr space. */
                if (inline_size > EXT4_MIN_INLINE_DATA_SIZE) {
                        if ((err = ext4_xattr_ibody_find(inode, &i, &is)) != 0)
                                goto out_error;

                        BUG_ON(is.s.not_found);

                        value_len = le32_to_cpu(is.s.here->e_value_size);
                        value = kmalloc(value_len, GFP_NOFS);
                        if (!value) {
                                err = -ENOMEM;
                                goto out_error;
                        }

                        err = ext4_xattr_ibody_get(inode, i.name_index,
                                                   i.name, value, value_len);
                        if (err <= 0)
                                goto out_error;

                        i.value = value;
                        i.value_len = i_size > EXT4_MIN_INLINE_DATA_SIZE ?
                                        i_size - EXT4_MIN_INLINE_DATA_SIZE : 0;
                        err = ext4_xattr_ibody_inline_set(handle, inode,
                                                          &i, &is);
                        if (err)
                                goto out_error;
                }

                /* Clear the content within i_blocks. */
                if (i_size < EXT4_MIN_INLINE_DATA_SIZE) {
                        void *p = (void *) ext4_raw_inode(&is.iloc)->i_block;
                        memset(p + i_size, 0,
                               EXT4_MIN_INLINE_DATA_SIZE - i_size);
                }

                EXT4_I(inode)->i_inline_size = i_size <
                                        EXT4_MIN_INLINE_DATA_SIZE ?
                                        EXT4_MIN_INLINE_DATA_SIZE : i_size;
        }

out_error:
        up_write(&EXT4_I(inode)->i_data_sem);
out:
        brelse(is.iloc.bh);
        ext4_write_unlock_xattr(inode, &no_expand);
        kfree(value);
        if (inode->i_nlink)
                ext4_orphan_del(handle, inode);

        if (err == 0) {
                inode->i_mtime = inode->i_ctime = current_time(inode);
                err = ext4_mark_inode_dirty(handle, inode);
                if (IS_SYNC(inode))
                        ext4_handle_sync(handle);
        }
        ext4_journal_stop(handle);
        return err;
}

int ext4_convert_inline_data(struct inode *inode)
{
        int error, needed_blocks, no_expand;
        handle_t *handle;

        struct ext4_iloc iloc;

        if (!ext4_has_inline_data(inode)) {
                ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
                return 0;
        }

        needed_blocks = ext4_writepage_trans_blocks(inode);

        iloc.bh = NULL;
        error = ext4_get_inode_loc(inode, &iloc);
        if (error)
                return error;

        handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
        if (IS_ERR(handle)) {
                error = PTR_ERR(handle);
                goto out_free;
        }

        ext4_write_lock_xattr(inode, &no_expand);
        if (ext4_has_inline_data(inode))
                error = ext4_convert_inline_data_nolock(handle, inode, &iloc);
        ext4_write_unlock_xattr(inode, &no_expand);
        ext4_journal_stop(handle);
out_free:
        brelse(iloc.bh);
        return error;
}