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

Hi Rommel,

Hi All,

U-Boot 2013.07-rc3 [ELDK 5.2.1 / ELDK 5.3]

Now I've started to use the new ext4 code. I need the "ext4write" command. Though there seems to be several problems with the ext2/ext4 code.

The ext4 code at u-boot (especially ext4write) needs special attention.

It is on top of my list to refactor and clean up this code base (especially the ext4write command).

I am testing on an ml507 (PPC440, Big Endian). There are some cases where the a field is 16-bit but le32_to_cpu() is used. Some checks (ie eh_magic) fails to match even if I use a correctly ext4 formatted MMC/SD card.

Does these seem right? Or am I mistaken?

I would need to double check it (since I'm using only ext4load at my target board currently).

---

diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c index 58880b4..22d4377 100644 --- a/fs/ext4/ext4_common.c +++ b/fs/ext4/ext4_common.c @@ -1429,7 +1429,7 @@ 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)

@@ -1437,14 +1437,14 @@ 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))
  

^^^^^ We had some problems with unaligned access to 16 bit values recently (when those start at 0x2). It was observed on our ARM Exynos4 based target.

		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(block << log2_blksz, 0, fs->blksz, buf)) @@ -1543,17 +1543,17 @@ 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);
  

---

(Sorry, I can't CC anyone directly as I'm using the gmane "post" interface)

You can also CC ext4 u-boot's implementation authors.

All the best, Rommel

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