ext4: Convert ext4_extent_idx.ei_leaf to ext4_extent_idx.ei_leaf_lo

Convert ext4_extent_idx.ei_leaf  ext4_extent_idx.ei_leaf_lo
This helps in finding BUGs due to direct partial access of
these split 48 bit values.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

fs/ext4/extents.c

@@ -65,7 +65,7 @@ static ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
 {
 	ext4_fsblk_t block;
 
-	block = le32_to_cpu(ix->ei_leaf);
+	block = le32_to_cpu(ix->ei_leaf_lo);
 	block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
 	return block;
 }
@@ -88,7 +88,7 @@ static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
  */
 static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
 {
-	ix->ei_leaf = cpu_to_le32((unsigned long) (pb & 0xffffffff));
+	ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
 	ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
 }
 

include/linux/ext4_fs_extents.h

@@ -83,7 +83,7 @@ struct ext4_extent {
  */
 struct ext4_extent_idx {
 	__le32	ei_block;	/* index covers logical blocks from 'block' */
-	__le32	ei_leaf;	/* pointer to the physical block of the next *
+	__le32	ei_leaf_lo;	/* pointer to the physical block of the next *
 				 * level. leaf or next index could be there */
 	__le16	ei_leaf_hi;	/* high 16 bits of physical block */
 	__u16	ei_unused;