[U-Boot] [PATCH] ext4fs: le32_to_cpu() used on a 16-bit field

[Lukasz Majewski]

On Sun, 21 Jul 2013 10:53:25 +0200 Andreas Bießmann
andreas.devel at googlemail.com wrote,

Hi Andreas,

> From: Rommel Custodio <sessyargc+uboot at gmail.com>
> 
> Fix reading ext4_extent_header struture on BE machines.
> Some 16 bit fields where converted to 32 bit fields, due to the byte
> swap on BE machines the containing value was corrupted. Therefore
> reading ext4 filesystems on BE machines where broken before.
> 
> Signed-off-by: Rommel Custodio <sessyargc+uboot at gmail.com>
> [sent via git-send-email; rework commit message]
> Signed-off-by: Andreas Bießmann <andreas.devel at googlemail.com>
> 
> ---
>  fs/ext4/ext4_common.c |   12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
> index 2776293..ff9c4ec 100644
> --- a/fs/ext4/ext4_common.c
> +++ b/fs/ext4/ext4_common.c
> @@ -1432,7 +1432,7 @@ static struct ext4_extent_header
> *ext4fs_get_extent_block while (1) {
>  		index = (struct ext4_extent_idx *)(ext_block + 1);
>  
> -		if (le32_to_cpu(ext_block->eh_magic) !=
> EXT4_EXT_MAGIC)
> +		if (le16_to_cpu(ext_block->eh_magic) !=
> EXT4_EXT_MAGIC) return 0;
>  
>  		if (ext_block->eh_depth == 0)
> @@ -1440,14 +1440,14 @@ static struct ext4_extent_header
> *ext4fs_get_extent_block i = -1;
>  		do {
>  			i++;
> -			if (i >= le32_to_cpu(ext_block->eh_entries))
> +			if (i >= le16_to_cpu(ext_block->eh_entries))
>  				break;
>  		} while (fileblock > le32_to_cpu(index[i].ei_block));
>  
>  		if (--i < 0)
>  			return 0;
>  
> -		block = le32_to_cpu(index[i].ei_leaf_hi);
> +		block = le16_to_cpu(index[i].ei_leaf_hi);
>  		block = (block << 32) +
> le32_to_cpu(index[i].ei_leaf_lo); 
>  		if (ext4fs_devread((lbaint_t)block << log2_blksz, 0,
> fs->blksz, @@ -1548,17 +1548,17 @@ long int
> read_allocated_block(struct ext2_inode *inode, int fileblock) 
>  		do {
>  			i++;
> -			if (i >= le32_to_cpu(ext_block->eh_entries))
> +			if (i >= le16_to_cpu(ext_block->eh_entries))
>  				break;
>  		} while (fileblock >=
> le32_to_cpu(extent[i].ee_block)); if (--i >= 0) {
>  			fileblock -= le32_to_cpu(extent[i].ee_block);
> -			if (fileblock >=
> le32_to_cpu(extent[i].ee_len)) {
> +			if (fileblock >=
> le16_to_cpu(extent[i].ee_len)) { free(buf);
>  				return 0;
>  			}
>  
> -			start = le32_to_cpu(extent[i].ee_start_hi);
> +			start = le16_to_cpu(extent[i].ee_start_hi);
>  			start = (start << 32) +
>  					le32_to_cpu(extent[i].ee_start_lo);
>  			free(buf);

I've tested this patch at LE Samsung Trats board. The code worked as
before (ext4ls, ext4load, ext4write) - also taking into account
limitation of our platform.

Tested-by: Lukasz Majewski <l.majewski at samsung.com>

However, we will not run out from refactoring this code.

-- 
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group