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 <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
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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