3 files changed, 39 insertions, 15 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a8454c401cee..90cc2c9bd79e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -136,8 +136,8 @@ struct node {
  * owner of the block and the number of references
  */
 struct extent_item {
-        u32 refs;
-        u64 owner;
+        __le32 refs;
+        __le64 owner;
 } __attribute__ ((__packed__));
 
 /*
@@ -153,6 +153,26 @@ struct ctree_path {
         int slots[MAX_LEVEL];
 };
 
+static inline u64 btrfs_extent_owner(struct extent_item *ei)
+{
+        return le64_to_cpu(ei->owner);
+}
+
+static inline void btrfs_set_extent_owner(struct extent_item *ei, u64 val)
+{
+        ei->owner = cpu_to_le64(val);
+}
+
+static inline u32 btrfs_extent_refs(struct extent_item *ei)
+{
+        return le32_to_cpu(ei->refs);
+}
+
+static inline void btrfs_set_extent_refs(struct extent_item *ei, u32 val)
+{
+        ei->refs = cpu_to_le32(val);
+}
+
 static inline u64 btrfs_node_blockptr(struct node *n, int nr)
 {
         return le64_to_cpu(n->blockptrs[nr]);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e511f48eb48e..1676a6595cce 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -29,6 +29,7 @@ static int inc_block_ref(struct ctree_root *root, u64 blocknr)
         struct leaf *l;
         struct extent_item *item;
         struct btrfs_key ins;
+        u32 refs;
 
         find_free_extent(root->extent_root, 0, 0, (u64)-1, &ins);
         init_path(&path);
@@ -42,7 +43,8 @@ static int inc_block_ref(struct ctree_root *root, u64 blocknr)
         l = &path.nodes[0]->leaf;
         item = (struct extent_item *)(l->data + btrfs_item_offset(l->items +
                                                                 path.slots[0]));
-        item->refs++;
+        refs = btrfs_extent_refs(item);
+        btrfs_set_extent_refs(item, refs + 1);
 
         BUG_ON(list_empty(&path.nodes[0]->dirty));
         release_path(root->extent_root, &path);
@@ -69,7 +71,7 @@ static int lookup_block_ref(struct ctree_root *root, u64 blocknr, u32 *refs)
         item = (struct extent_item *)(l->data +
                                       btrfs_item_offset(l->items +
                                                         path.slots[0]));
-        *refs = item->refs;
+        *refs = btrfs_extent_refs(item);
         release_path(root->extent_root, &path);
         return 0;
 }
@@ -120,9 +122,9 @@ static int finish_current_insert(struct ctree_root *extent_root)
         int i;
         int ret;
 
-        extent_item.refs = 1;
-        extent_item.owner =
-                btrfs_header_parentid(&extent_root->node->node.header);
+        btrfs_set_extent_refs(&extent_item, 1);
+        btrfs_set_extent_owner(&extent_item,
+                btrfs_header_parentid(&extent_root->node->node.header));
         ins.offset = 1;
         ins.flags = 0;
 
@@ -148,6 +150,7 @@ int __free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
         struct btrfs_item *item;
         struct extent_item *ei;
         struct btrfs_key ins;
+        u32 refs;
 
         key.objectid = blocknr;
         key.flags = 0;
@@ -166,8 +169,9 @@ int __free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks)
         ei = (struct extent_item *)(path.nodes[0]->leaf.data +
                                     btrfs_item_offset(item));
         BUG_ON(ei->refs == 0);
-        ei->refs--;
-        if (ei->refs == 0) {
+        refs = btrfs_extent_refs(ei) - 1;
+        btrfs_set_extent_refs(ei, refs);
+        if (refs == 0) {
                 if (root == extent_root) {
                         int err;
                         radix_tree_preload(GFP_KERNEL);
@@ -368,8 +372,8 @@ int alloc_extent(struct ctree_root *root, u64 num_blocks, u64 search_start,
         struct ctree_root *extent_root = root->extent_root;
         struct extent_item extent_item;
 
-        extent_item.refs = 1;
-        extent_item.owner = owner;
+        btrfs_set_extent_refs(&extent_item, 1);
+        btrfs_set_extent_owner(&extent_item, owner);
 
         if (root == extent_root) {
                 BUG_ON(extent_root->current_insert.offset == 0);
diff --git a/fs/btrfs/mkfs.c b/fs/btrfs/mkfs.c
index 0f77babcd306..e0d3bc1d0259 100644
--- a/fs/btrfs/mkfs.c
+++ b/fs/btrfs/mkfs.c
@@ -51,8 +51,8 @@ int mkfs(int fd)
         btrfs_set_item_offset(&item,
                               LEAF_DATA_SIZE - sizeof(struct extent_item));
         btrfs_set_item_size(&item, sizeof(struct extent_item));
-        extent_item.refs = 1;
-        extent_item.owner = 0;
+        btrfs_set_extent_refs(&extent_item, 1);
+        btrfs_set_extent_owner(&extent_item, 0);
         memcpy(empty_leaf.items, &item, sizeof(item));
         memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
                 btrfs_item_size(&item));
@@ -62,7 +62,7 @@ int mkfs(int fd)
         btrfs_set_key_offset(&item.key, 1);
         btrfs_set_item_offset(&item,
                               LEAF_DATA_SIZE - sizeof(struct extent_item) * 2);
-        extent_item.owner = 1;
+        btrfs_set_extent_owner(&extent_item, 1);
         memcpy(empty_leaf.items + 1, &item, sizeof(item));
         memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
                 btrfs_item_size(&item));
@@ -72,7 +72,7 @@ int mkfs(int fd)
         btrfs_set_key_offset(&item.key, 1);
         btrfs_set_item_offset(&item,
                               LEAF_DATA_SIZE - sizeof(struct extent_item) * 3);
-        extent_item.owner = 2;
+        btrfs_set_extent_owner(&extent_item, 2);
         memcpy(empty_leaf.items + 2, &item, sizeof(item));
         memcpy(empty_leaf.data + btrfs_item_offset(&item), &extent_item,
                 btrfs_item_size(&item));