ext4 file system layout contain different split members
like bg_block_bitmap  and bg_block_bitmap_hi. Introduce
data type le32_t and le16_t to be used as the type of
these split members. This prevents these members frome
being accessed directly. Accesing them directly gives
a compiler warning. This helps in catching some BUGS
due to direct partial access of these split fields.

Signed-off-by: Aneesh Kumar K.V <[EMAIL PROTECTED]>
---
 fs/ext4/super.c           |    8 ++++----
 include/linux/ext4_fs.h   |    4 ++--
 include/linux/ext4_fs_i.h |    4 ++++
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d035653..c8f8e4d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -70,9 +70,9 @@ static void ext4_write_super_lockfs(struct super_block *sb);
 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
                               struct ext4_group_desc *bg)
 {
-       return le32_to_cpu(bg->bg_block_bitmap) |
+       return le32_to_cpu(bg->bg_block_bitmap.value) |
                (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
-                (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
+                (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi.value) << 32 
: 0);
 }
 
 ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
@@ -94,9 +94,9 @@ ext4_fsblk_t ext4_inode_table(struct super_block *sb,
 void ext4_block_bitmap_set(struct super_block *sb,
                           struct ext4_group_desc *bg, ext4_fsblk_t blk)
 {
-       bg->bg_block_bitmap = cpu_to_le32((u32)blk);
+       bg->bg_block_bitmap.value = cpu_to_le32((u32)blk);
        if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
-               bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
+               bg->bg_block_bitmap_hi.value = cpu_to_le32(blk >> 32);
 }
 
 void ext4_inode_bitmap_set(struct super_block *sb,
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index 046a6a7..4494f8e 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -150,7 +150,7 @@ struct ext4_allocation_request {
  */
 struct ext4_group_desc
 {
-       __le32  bg_block_bitmap;        /* Blocks bitmap block */
+       le32_t  bg_block_bitmap;        /* Blocks bitmap block */
        __le32  bg_inode_bitmap;        /* Inodes bitmap block */
        __le32  bg_inode_table;         /* Inodes table block */
        __le16  bg_free_blocks_count;   /* Free blocks count */
@@ -160,7 +160,7 @@ struct ext4_group_desc
        __u32   bg_reserved[2];         /* Likely block/inode bitmap checksum */
        __le16  bg_itable_unused;       /* Unused inodes count */
        __le16  bg_checksum;            /* crc16(sb_uuid+group+desc) */
-       __le32  bg_block_bitmap_hi;     /* Blocks bitmap block MSB */
+       le32_t  bg_block_bitmap_hi;     /* Blocks bitmap block MSB */
        __le32  bg_inode_bitmap_hi;     /* Inodes bitmap block MSB */
        __le32  bg_inode_table_hi;      /* Inodes table block MSB */
 };
diff --git a/include/linux/ext4_fs_i.h b/include/linux/ext4_fs_i.h
index 22ba80e..d7eb271 100644
--- a/include/linux/ext4_fs_i.h
+++ b/include/linux/ext4_fs_i.h
@@ -27,6 +27,10 @@ typedef int ext4_grpblk_t;
 /* data type for filesystem-wide blocks number */
 typedef unsigned long long ext4_fsblk_t;
 
+/* data type to carry split 64 and 48 bits */
+typedef struct { __le16 value; } le16_t;
+typedef struct { __le32 value; } le32_t;
+
 struct ext4_reserve_window {
        ext4_fsblk_t    _rsv_start;     /* First byte reserved */
        ext4_fsblk_t    _rsv_end;       /* Last byte reserved or 0 */
-- 
1.5.3.1.91.gd3392-dirty

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