ext4: reimplement convert and split_unwritten

Reimplement ext4_ext_convert_to_initialized() and
ext4_split_unwritten_extents() using ext4_split_extent()

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Tested-by: Allison Henderson <achender@linux.vnet.ibm.com>
static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
			      ext4_lblk_t lblk,
			      struct ext4_ext_path *path,
			      unsigned int len)
{
	int i, depth;
	struct ext4_extent_header *eh;
	struct ext4_extent *last_ex;

	if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
		return 0;

	depth = ext_depth(inode);
	eh = path[depth].p_hdr;

	if (unlikely(!eh->eh_entries)) {
		EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
				 "EOFBLOCKS_FL set");
		return -EIO;
	}
	last_ex = EXT_LAST_EXTENT(eh);
	/*
	 * We should clear the EOFBLOCKS_FL flag if we are writing the
	 * last block in the last extent in the file.  We test this by
	 * first checking to see if the caller to
	 * ext4_ext_get_blocks() was interested in the last block (or
	 * a block beyond the last block) in the current extent.  If
	 * this turns out to be false, we can bail out from this
	 * function immediately.
	 */
	if (lblk + len < le32_to_cpu(last_ex->ee_block) +
	    ext4_ext_get_actual_len(last_ex))
		return 0;
	/*
	 * If the caller does appear to be planning to write at or
	 * beyond the end of the current extent, we then test to see
	 * if the current extent is the last extent in the file, by
	 * checking to make sure it was reached via the rightmost node
	 * at each level of the tree.
	 */
	for (i = depth-1; i >= 0; i--)
		if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
			return 0;
	ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
	return ext4_mark_inode_dirty(handle, inode);
}

static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
			      ext4_lblk_t lblk,
			      struct ext4_ext_path *path,
			      unsigned int len)
{
	int i, depth;
	struct ext4_extent_header *eh;
	struct ext4_extent *last_ex;

	if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
		return 0;

	depth = ext_depth(inode);
	eh = path[depth].p_hdr;

	if (unlikely(!eh->eh_entries)) {
		EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
				 "EOFBLOCKS_FL set");
		return -EIO;
	}
	last_ex = EXT_LAST_EXTENT(eh);
	/*
	 * We should clear the EOFBLOCKS_FL flag if we are writing the
	 * last block in the last extent in the file.  We test this by
	 * first checking to see if the caller to
	 * ext4_ext_get_blocks() was interested in the last block (or
	 * a block beyond the last block) in the current extent.  If
	 * this turns out to be false, we can bail out from this
	 * function immediately.
	 */
	if (lblk + len < le32_to_cpu(last_ex->ee_block) +
	    ext4_ext_get_actual_len(last_ex))
		return 0;
	/*
	 * If the caller does appear to be planning to write at or
	 * beyond the end of the current extent, we then test to see
	 * if the current extent is the last extent in the file, by
	 * checking to make sure it was reached via the rightmost node
	 * at each level of the tree.
	 */
	for (i = depth-1; i >= 0; i--)
		if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
			return 0;
	ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
	return ext4_mark_inode_dirty(handle, inode);
}
