ext4: Convert ext4_extent.ee_start to ext4_extent.ee_start_lo

Convert ext4_extent.ee_start to ext4_extent.ee_start_lo
This helps in finding BUGs due to direct partial access of
these split 48 bit values

Also fix direct partial access in ext4 code

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

2 files changed, 4 insertions, 6 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 2be404f68a76..c03056aafcdb 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -52,7 +52,7 @@ static ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
 {
         ext4_fsblk_t block;
 
-        block = le32_to_cpu(ex->ee_start);
+        block = le32_to_cpu(ex->ee_start_lo);
         block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
         return block;
 }
@@ -77,7 +77,7 @@ static ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
  */
 static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
 {
-        ex->ee_start = cpu_to_le32((unsigned long) (pb & 0xffffffff));
+        ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
         ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
 }
 
@@ -1409,8 +1409,7 @@ has_space:
         eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1);
         nearex = path[depth].p_ext;
         nearex->ee_block = newext->ee_block;
-        nearex->ee_start = newext->ee_start;
-        nearex->ee_start_hi = newext->ee_start_hi;
+        ext4_ext_store_pblock(nearex, ext_pblock(newext));
         nearex->ee_len = newext->ee_len;
 
 merge:
@@ -2177,7 +2176,6 @@ int ext4_ext_convert_to_initialized(handle_t *handle, struct inode *inode,
         }
         /* ex2: iblock to iblock + maxblocks-1 : initialised */
         ex2->ee_block = cpu_to_le32(iblock);
-        ex2->ee_start = cpu_to_le32(newblock);
         ext4_ext_store_pblock(ex2, newblock);
         ex2->ee_len = cpu_to_le16(allocated);
         if (ex2 != ex)
diff --git a/include/linux/ext4_fs_extents.h b/include/linux/ext4_fs_extents.h
index 81406f3655d4..cb2dfbbc969a 100644
--- a/include/linux/ext4_fs_extents.h
+++ b/include/linux/ext4_fs_extents.h
@@ -74,7 +74,7 @@ struct ext4_extent {
         __le32  ee_block;       /* first logical block extent covers */
         __le16  ee_len;         /* number of blocks covered by extent */
         __le16  ee_start_hi;    /* high 16 bits of physical block */
-        __le32  ee_start;       /* low 32 bits of physical block */
+        __le32  ee_start_lo;    /* low 32 bits of physical block */
 };
 
 /*