text: /*
   * Copyright (c) 2012 Taobao.
   * Written by Tao Ma <boyu.mt@taobao.com>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of version 2.1 of the GNU Lesser General Public License
   * as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #include <linux/fiemap.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_block && 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) {
  		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;
  
  	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)
  		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;
  	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;
  
  	down_write(&EXT4_I(inode)->xattr_sem);
  
  	if (ei->i_inline_off)
  		ret = ext4_update_inline_data(handle, inode, len);
  	else
  		ret = ext4_create_inline_data(handle, inode, len);
  
  	up_write(&EXT4_I(inode)->xattr_sem);
  
  	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);
  
  	if (EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb,
  				      EXT4_FEATURE_INCOMPAT_EXTENTS)) {
  		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_CACHE_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_CACHE_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;
  	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;
  	}
  
  	down_write(&EXT4_I(inode)->xattr_sem);
  	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_write);
  	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);
  		page_cache_release(page);
  		page = NULL;
  		ext4_orphan_add(handle, inode);
  		up_write(&EXT4_I(inode)->xattr_sem);
  		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);
  		page_cache_release(page);
  	}
  	if (sem_held)
  		up_write(&EXT4_I(inode)->xattr_sem);
  	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;
  	}
  
  	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);
  		page_cache_release(page);
  		goto out_up_read;
  	}
  
  	if (!PageUptodate(page)) {
  		ret = ext4_read_inline_page(inode, page);
  		if (ret < 0)
  			goto out_up_read;
  	}
  
  	ret = 1;
  	handle = NULL;
  out_up_read:
  	up_read(&EXT4_I(inode)->xattr_sem);
  out:
  	if (handle)
  		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;
  	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;
  	}
  
  	down_write(&EXT4_I(inode)->xattr_sem);
  	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);
  
  	up_write(&EXT4_I(inode)->xattr_sem);
  	brelse(iloc.bh);
  out:
  	return copied;
  }
  
  struct buffer_head *
  ext4_journalled_write_inline_data(struct inode *inode,
  				  unsigned len,
  				  struct page *page)
  {
  	int ret;
  	void *kaddr;
  	struct ext4_iloc iloc;
  
  	ret = ext4_get_inode_loc(inode, &iloc);
  	if (ret) {
  		ext4_std_error(inode->i_sb, ret);
  		return NULL;
  	}
  
  	down_write(&EXT4_I(inode)->xattr_sem);
  	kaddr = kmap_atomic(page);
  	ext4_write_inline_data(inode, &iloc, kaddr, 0, len);
  	kunmap_atomic(kaddr);
  	up_write(&EXT4_I(inode)->xattr_sem);
  
  	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);
  		page_cache_release(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);
  		page_cache_release(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;
  
  	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) {
  		ret = ext4_da_convert_inline_data_to_extent(mapping,
  							    inode,
  							    flags,
  							    fsdata);
  		ext4_journal_stop(handle);
  		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;
  	}
  
  	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);
  	page_cache_release(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 i_size_changed = 0;
  
  	copied = ext4_write_inline_data_end(inode, pos, len, copied, page);
  
  	/*
  	 * 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);
  		i_size_changed = 1;
  	}
  	unlock_page(page);
  	page_cache_release(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.
  	 */
  	if (i_size_changed)
  		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 dentry *dentry,
  				     struct inode *inode,
  				     struct ext4_iloc *iloc,
  				     void *inline_start, int inline_size)
  {
  	struct inode	*dir = d_inode(dentry->d_parent);
  	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(dir, 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 = ext4_current_time(dir);
  	ext4_update_dx_flag(dir);
  	dir->i_version++;
  	ext4_mark_inode_dirty(handle, 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;
  	struct ext4_dir_entry_tail *t;
  	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) {
  		t = EXT4_DIRENT_TAIL(dir_block->b_data,
  				     inode->i_sb->s_blocksize);
  		initialize_dirent_tail(t, inode->i_sb->s_blocksize);
  	}
  	set_buffer_uptodate(dir_block);
  	err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
  	if (err)
  		goto out;
  	set_buffer_verified(dir_block);
  out:
  	return err;
  }
  
  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 dentry *dentry, struct inode *inode)
  {
  	int ret, inline_size;
  	void *inline_start;
  	struct ext4_iloc iloc;
  	struct inode *dir = d_inode(dentry->d_parent);
  
  	ret = ext4_get_inode_loc(dir, &iloc);
  	if (ret)
  		return ret;
  
  	down_write(&EXT4_I(dir)->xattr_sem);
  	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, dentry, 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, dentry,
  						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_mark_inode_dirty(handle, dir);
  	up_write(&EXT4_I(dir)->xattr_sem);
  	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 htree_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 ext4_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(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 (file->f_version != inode->i_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->i_version;
  	}
  
  	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,
  					const struct qstr *d_name,
  					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, d_name, 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, d_name, 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;
  	struct ext4_iloc iloc;
  	void *inline_start;
  
  	err = ext4_get_inode_loc(dir, &iloc);
  	if (err)
  		return err;
  
  	down_write(&EXT4_I(dir)->xattr_sem);
  	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;
  
  	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
  	err = ext4_mark_inode_dirty(handle, dir);
  	if (unlikely(err))
  		goto out;
  
  	ext4_show_inline_dir(dir, iloc.bh, inline_start, inline_size);
  out:
  	up_write(&EXT4_I(dir)->xattr_sem);
  	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);
  }
  
  int empty_inline_dir(struct inode *dir, int *has_inline_data)
  {
  	int err, inline_size;
  	struct ext4_iloc iloc;
  	void *inline_pos;
  	unsigned int offset;
  	struct ext4_dir_entry_2 *de;
  	int ret = 1;
  
  	err = ext4_get_inode_loc(dir, &iloc);
  	if (err) {
  		EXT4_ERROR_INODE(dir, "error %d getting inode %lu block",
  				 err, dir->i_ino);
  		return 1;
  	}
  
  	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 = 1;
  		goto out;
  	}
  
  	offset = EXT4_INLINE_DOTDOT_SIZE;
  	while (offset < dir->i_size) {
  		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\n",
  				     dir->i_ino, le32_to_cpu(de->inode),
  				     le16_to_cpu(de->rec_len), de->name_len,
  				     inline_size);
  			ret = 1;
  			goto out;
  		}
  		if (le32_to_cpu(de->inode)) {
  			ret = 0;
  			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;
  
  	down_write(&EXT4_I(inode)->xattr_sem);
  	ret = ext4_destroy_inline_data_nolock(handle, inode);
  	up_write(&EXT4_I(inode)->xattr_sem);
  
  	return ret;
  }
  
  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);
  
  	if (physical)
  		error = fiemap_fill_next_extent(fieinfo, start, physical,
  						inline_len, flags);
  	brelse(iloc.bh);
  out:
  	up_read(&EXT4_I(inode)->xattr_sem);
  	return (error < 0 ? error : 0);
  }
  
  /*
   * Called during xattr set, and if we can sparse space 'needed',
   * just create the extent tree evict the data to the outer block.
   *
   * We use jbd2 instead of page cache to move data to the 1st block
   * so that the whole transaction can be committed as a whole and
   * the data isn't lost because of the delayed page cache write.
   */
  int ext4_try_to_evict_inline_data(handle_t *handle,
  				  struct inode *inode,
  				  int needed)
  {
  	int error;
  	struct ext4_xattr_entry *entry;
  	struct ext4_inode *raw_inode;
  	struct ext4_iloc iloc;
  
  	error = ext4_get_inode_loc(inode, &iloc);
  	if (error)
  		return error;
  
  	raw_inode = ext4_raw_inode(&iloc);
  	entry = (struct ext4_xattr_entry *)((void *)raw_inode +
  					    EXT4_I(inode)->i_inline_off);
  	if (EXT4_XATTR_LEN(entry->e_name_len) +
  	    EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size)) < needed) {
  		error = -ENOSPC;
  		goto out;
  	}
  
  	error = ext4_convert_inline_data_nolock(handle, inode, &iloc);
  out:
  	brelse(iloc.bh);
  	return error;
  }
  
  void ext4_inline_data_truncate(struct inode *inode, int *has_inline)
  {
  	handle_t *handle;
  	int inline_size, value_len, needed_blocks;
  	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;
  
  	down_write(&EXT4_I(inode)->xattr_sem);
  	if (!ext4_has_inline_data(inode)) {
  		*has_inline = 0;
  		ext4_journal_stop(handle);
  		return;
  	}
  
  	if (ext4_orphan_add(handle, inode))
  		goto out;
  
  	if (ext4_get_inode_loc(inode, &is.iloc))
  		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 (ext4_xattr_ibody_find(inode, &i, &is))
  				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)
  				goto out_error;
  
  			if (ext4_xattr_ibody_get(inode, i.name_index, i.name,
  						value, value_len))
  				goto out_error;
  
  			i.value = value;
  			i.value_len = i_size > EXT4_MIN_INLINE_DATA_SIZE ?
  					i_size - EXT4_MIN_INLINE_DATA_SIZE : 0;
  			if (ext4_xattr_ibody_inline_set(handle, inode, &i, &is))
  				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);
  	up_write(&EXT4_I(inode)->xattr_sem);
  	kfree(value);
  	if (inode->i_nlink)
  		ext4_orphan_del(handle, inode);
  
  	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
  	ext4_mark_inode_dirty(handle, inode);
  	if (IS_SYNC(inode))
  		ext4_handle_sync(handle);
  
  	ext4_journal_stop(handle);
  	return;
  }
  
  int ext4_convert_inline_data(struct inode *inode)
  {
  	int error, needed_blocks;
  	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;
  	}
  
  	down_write(&EXT4_I(inode)->xattr_sem);
  	if (!ext4_has_inline_data(inode)) {
  		up_write(&EXT4_I(inode)->xattr_sem);
  		goto out;
  	}
  
  	error = ext4_convert_inline_data_nolock(handle, inode, &iloc);
  	up_write(&EXT4_I(inode)->xattr_sem);
  out:
  	ext4_journal_stop(handle);
  out_free:
  	brelse(iloc.bh);
  	return error;
  }
  