[U-Boot] [PATCH] ext4fs: Add ext4 extent cache for read operations

[Ionut Nicu]

Hi,

On 21.01.2014 10:58, Ionut Nicu wrote:
> 
> +static int __ext4fs_build_extent_cache(struct ext2_data *data,
> +		struct ext4_extent_header *ext_block)
>  {
> +	int blksz = EXT2_BLOCK_SIZE(data);
> +	int log2_blksz = LOG2_BLOCK_SIZE(data)
> +		- get_fs()->dev_desc->log2blksz;
> +	struct ext4_extent_node *node;
>  	struct ext4_extent_idx *index;
> +	struct ext4_extent *extent;
>  	unsigned long long block;
> -	int blksz = EXT2_BLOCK_SIZE(data);
> -	int i;
> +	char *buf;
> +	int i, err;
>  
> -	while (1) {
> -		index = (struct ext4_extent_idx *)(ext_block + 1);
> +	if (le16_to_cpu(ext_block->eh_magic) != EXT4_EXT_MAGIC)
> +		return -EINVAL;
>  
> -		if (le16_to_cpu(ext_block->eh_magic) != EXT4_EXT_MAGIC)
> -			return 0;
> -
> -		if (ext_block->eh_depth == 0)
> -			return ext_block;
> -		i = -1;
> -		do {
> -			i++;
> -			if (i >= le16_to_cpu(ext_block->eh_entries))
> -				break;
> -		} while (fileblock >= le32_to_cpu(index[i].ei_block));
> +	if (ext_block->eh_depth == 0) {
> +		extent = (struct ext4_extent *)(ext_block + 1);
> +		for (i = 0; i < le16_to_cpu(ext_block->eh_entries); i++) {
> +			node = malloc(sizeof(*node));
> +			if (!node)
> +				return -ENOMEM;
> +			node->block = le32_to_cpu(extent[i].ee_block);
> +			node->len = le16_to_cpu(extent[i].ee_len);
> +			node->start = (le16_to_cpu(extent[i].ee_start_hi) << 16)
> +				+ le32_to_cpu(extent[i].ee_start_lo);

Should be (le16_to_cpu(extent[i].ee_start_hi) << 32)

> diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
> index 735b256..7963f1d 100644
> --- a/fs/ext4/ext4fs.c
> +++ b/fs/ext4/ext4fs.c
> @@ -176,10 +176,25 @@ int ext4fs_ls(const char *dirname)
>  
>  int ext4fs_read(char *buf, unsigned len)
>  {
> +	int ret;
> +
>  	if (ext4fs_root == NULL || ext4fs_file == NULL)
>  		return 0;
>  
> -	return ext4fs_read_file(ext4fs_file, 0, len, buf);
> +	if (le32_to_cpu(ext4fs_file->inode.flags) & EXT4_EXTENTS_FL) {
> +		if (ext4fs_build_extent_cache(&(ext4fs_file->inode))) {
> +			printf("Error building extent cache!\n");
> +			ret = -1;
> +			goto out_exit;
> +		}
> +	}
> +
> +	ret = ext4fs_read_file(ext4fs_file, 0, len, buf);
> +
> +out_exit:
> +	ext4fs_free_extent_cache();
> +
> +	return ret;
>  }
>  

ext4fs_read_file is also called by ext4fs_iterate_dir and ext4fs_read_symlink
so the place where we build the extent cache should be ext4fs_read_file instead
of extfs_read.

Please ignore this version of the patch for now, I will send a revised version.

Regards,
Ionut