Btrfs: get/set for struct header fields

Signed-off-by: Chris Mason <chris.mason@oracle.com>

10 files changed, 230 insertions, 172 deletions

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index ae7f4c00c39c..f8532200e9ad 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -25,7 +25,7 @@ tester: $(objects) random-test.o
 quick-test: $(objects) quick-test.o
         gcc $(CFLAGS) -o quick-test $(objects) quick-test.o
 
-$(objects) : $(headers)
+$(objects): $(headers)
 
 clean :
         rm debug-tree tester *.o
diff --git a/fs/btrfs/TODO b/fs/btrfs/TODO
index 5c4395c3784a..52d2a7a071f4 100644
--- a/fs/btrfs/TODO
+++ b/fs/btrfs/TODO
@@ -1,4 +1,5 @@
 * cleanup, add more error checking, get rid of BUG_ONs
+* endian fixes
 * Make IO functions look more like the page cache
 * Fix ENOSPC handling
 * make blocksize a mkfs parameter instead of #define
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 729d4ddb3746..e43c827e0dfd 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -48,7 +48,7 @@ int btrfs_cow_block(struct ctree_root *root,
         }
         cow = alloc_free_block(root);
         memcpy(&cow->node, &buf->node, sizeof(buf->node));
-        cow->node.header.blocknr = cow->blocknr;
+        btrfs_set_header_blocknr(&cow->node.header, cow->blocknr);
         *cow_ret = cow;
         btrfs_inc_ref(root, buf);
         if (buf == root->node) {
@@ -73,7 +73,7 @@ int btrfs_cow_block(struct ctree_root *root,
  */
 static inline unsigned int leaf_data_end(struct leaf *leaf)
 {
-        unsigned int nr = leaf->header.nritems;
+        u32 nr = btrfs_header_nritems(&leaf->header);
         if (nr == 0)
                 return sizeof(leaf->data);
         return leaf->items[nr-1].offset;
@@ -87,7 +87,7 @@ static inline unsigned int leaf_data_end(struct leaf *leaf)
 int leaf_free_space(struct leaf *leaf)
 {
         int data_end = leaf_data_end(leaf);
-        int nritems = leaf->header.nritems;
+        int nritems = btrfs_header_nritems(&leaf->header);
         char *items_end = (char *)(leaf->items + nritems + 1);
         return (char *)(leaf->data + data_end) - (char *)items_end;
 }
@@ -118,18 +118,21 @@ int check_node(struct ctree_path *path, int level)
         struct node *parent = NULL;
         struct node *node = &path->nodes[level]->node;
         int parent_slot;
+        u32 nritems = btrfs_header_nritems(&node->header);
 
         if (path->nodes[level + 1])
                 parent = &path->nodes[level + 1]->node;
         parent_slot = path->slots[level + 1];
-        if (parent && node->header.nritems > 0) {
+        BUG_ON(nritems == 0);
+        if (parent) {
                 struct key *parent_key;
                 parent_key = &parent->keys[parent_slot];
                 BUG_ON(memcmp(parent_key, node->keys, sizeof(struct key)));
-                BUG_ON(parent->blockptrs[parent_slot] != node->header.blocknr);
+                BUG_ON(parent->blockptrs[parent_slot] !=
+                       btrfs_header_blocknr(&node->header));
         }
-        BUG_ON(node->header.nritems > NODEPTRS_PER_BLOCK);
-        for (i = 0; i < node->header.nritems - 2; i++) {
+        BUG_ON(nritems > NODEPTRS_PER_BLOCK);
+        for (i = 0; nritems > 1 && i < nritems - 2; i++) {
                 BUG_ON(comp_keys(&node->keys[i], &node->keys[i+1]) >= 0);
         }
         return 0;
@@ -141,18 +144,25 @@ int check_leaf(struct ctree_path *path, int level)
         struct leaf *leaf = &path->nodes[level]->leaf;
         struct node *parent = NULL;
         int parent_slot;
+        u32 nritems = btrfs_header_nritems(&leaf->header);
 
         if (path->nodes[level + 1])
                 parent = &path->nodes[level + 1]->node;
         parent_slot = path->slots[level + 1];
-        if (parent && leaf->header.nritems > 0) {
+        BUG_ON(leaf_free_space(leaf) < 0);
+
+        if (nritems == 0)
+                return 0;
+
+        if (parent) {
                 struct key *parent_key;
                 parent_key = &parent->keys[parent_slot];
                 BUG_ON(memcmp(parent_key, &leaf->items[0].key,
                        sizeof(struct key)));
-                BUG_ON(parent->blockptrs[parent_slot] != leaf->header.blocknr);
+                BUG_ON(parent->blockptrs[parent_slot] !=
+                       btrfs_header_blocknr(&leaf->header));
         }
-        for (i = 0; i < leaf->header.nritems - 2; i++) {
+        for (i = 0; nritems > 1 && i < nritems - 2; i++) {
                 BUG_ON(comp_keys(&leaf->items[i].key,
                                  &leaf->items[i+1].key) >= 0);
                 BUG_ON(leaf->items[i].offset != leaf->items[i + 1].offset +
@@ -162,7 +172,6 @@ int check_leaf(struct ctree_path *path, int level)
                                 LEAF_DATA_SIZE);
                 }
         }
-        BUG_ON(leaf_free_space(leaf) < 0);
         return 0;
 }
 
@@ -215,13 +224,15 @@ int generic_bin_search(char *p, int item_size, struct key *key,
  */
 int bin_search(struct node *c, struct key *key, int *slot)
 {
-        if (is_leaf(c->header.flags)) {
+        if (btrfs_is_leaf(c)) {
                 struct leaf *l = (struct leaf *)c;
                 return generic_bin_search((void *)l->items, sizeof(struct item),
-                                          key, c->header.nritems, slot);
+                                          key, btrfs_header_nritems(&c->header),
+                                          slot);
         } else {
                 return generic_bin_search((void *)c->keys, sizeof(struct key),
-                                          key, c->header.nritems, slot);
+                                          key, btrfs_header_nritems(&c->header),
+                                          slot);
         }
         return -1;
 }
@@ -233,7 +244,7 @@ struct tree_buffer *read_node_slot(struct ctree_root *root,
         struct node *node = &parent_buf->node;
         if (slot < 0)
                 return NULL;
-        if (slot >= node->header.nritems)
+        if (slot >= btrfs_header_nritems(&node->header))
                 return NULL;
         return read_tree_block(root, node->blockptrs[slot]);
 }
@@ -270,7 +281,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path,
                 struct tree_buffer *child;
                 u64 blocknr = mid_buf->blocknr;
 
-                if (mid->header.nritems != 1)
+                if (btrfs_header_nritems(&mid->header) != 1)
                         return 0;
 
                 /* promote the child to a root */
@@ -287,7 +298,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path,
         }
         parent = &parent_buf->node;
 
-        if (mid->header.nritems > NODEPTRS_PER_BLOCK / 4)
+        if (btrfs_header_nritems(&mid->header) > NODEPTRS_PER_BLOCK / 4)
                 return 0;
 
         left_buf = read_node_slot(root, parent_buf, pslot - 1);
@@ -298,7 +309,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path,
                 btrfs_cow_block(root, left_buf, parent_buf,
                                 pslot - 1, &left_buf);
                 left = &left_buf->node;
-                orig_slot += left->header.nritems;
+                orig_slot += btrfs_header_nritems(&left->header);
                 wret = push_node_left(root, left_buf, mid_buf);
                 if (wret < 0)
                         ret = wret;
@@ -314,7 +325,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path,
                 wret = push_node_left(root, mid_buf, right_buf);
                 if (wret < 0)
                         ret = wret;
-                if (right->header.nritems == 0) {
+                if (btrfs_header_nritems(&right->header) == 0) {
                         u64 blocknr = right_buf->blocknr;
                         tree_block_release(root, right_buf);
                         clean_tree_block(root, right_buf);
@@ -332,7 +343,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path,
                         BUG_ON(list_empty(&parent_buf->dirty));
                 }
         }
-        if (mid->header.nritems == 1) {
+        if (btrfs_header_nritems(&mid->header) == 1) {
                 /*
                  * we're not allowed to leave a node with one item in the
                  * tree during a delete.  A deletion from lower in the tree
@@ -348,7 +359,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path,
                         ret = wret;
                 BUG_ON(wret == 1);
         }
-        if (mid->header.nritems == 0) {
+        if (btrfs_header_nritems(&mid->header) == 0) {
                 /* we've managed to empty the middle node, drop it */
                 u64 blocknr = mid_buf->blocknr;
                 tree_block_release(root, mid_buf);
@@ -369,7 +380,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path,
 
         /* update the path */
         if (left_buf) {
-                if (left->header.nritems > orig_slot) {
+                if (btrfs_header_nritems(&left->header) > orig_slot) {
                         left_buf->count++; // released below
                         path->nodes[level] = left_buf;
                         path->slots[level + 1] -= 1;
@@ -377,7 +388,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path,
                         if (mid_buf)
                                 tree_block_release(root, mid_buf);
                 } else {
-                        orig_slot -= left->header.nritems;
+                        orig_slot -= btrfs_header_nritems(&left->header);
                         path->slots[level] = orig_slot;
                 }
         }
@@ -420,7 +431,7 @@ again:
         b = root->node;
         b->count++;
         while (b) {
-                level = node_level(b->node.header.flags);
+                level = btrfs_header_level(&b->node.header);
                 if (cow) {
                         int wret;
                         wret = btrfs_cow_block(root, b, p->nodes[level + 1],
@@ -434,12 +445,12 @@ again:
                 if (ret)
                         return -1;
                 ret = bin_search(c, key, &slot);
-                if (!is_leaf(c->header.flags)) {
+                if (!btrfs_is_leaf(c)) {
                         if (ret && slot > 0)
                                 slot -= 1;
                         p->slots[level] = slot;
-                        if (ins_len > 0 &&
-                            c->header.nritems == NODEPTRS_PER_BLOCK) {
+                        if (ins_len > 0 && btrfs_header_nritems(&c->header) ==
+                            NODEPTRS_PER_BLOCK) {
                                 int sret = split_node(root, p, level);
                                 BUG_ON(sret > 0);
                                 if (sret)
@@ -456,7 +467,7 @@ again:
                                         goto again;
                                 c = &b->node;
                                 slot = p->slots[level];
-                                BUG_ON(c->header.nritems == 1);
+                                BUG_ON(btrfs_header_nritems(&c->header) == 1);
                         }
                         b = read_tree_block(root, c->blockptrs[slot]);
                 } else {
@@ -524,8 +535,8 @@ static int push_node_left(struct ctree_root *root, struct tree_buffer *dst_buf,
         int dst_nritems;
         int ret = 0;
 
-        src_nritems = src->header.nritems;
-        dst_nritems = dst->header.nritems;
+        src_nritems = btrfs_header_nritems(&src->header);
+        dst_nritems = btrfs_header_nritems(&dst->header);
         push_items = NODEPTRS_PER_BLOCK - dst_nritems;
         if (push_items <= 0) {
                 return 1;
@@ -544,9 +555,8 @@ static int push_node_left(struct ctree_root *root, struct tree_buffer *dst_buf,
                 memmove(src->blockptrs, src->blockptrs + push_items,
                         (src_nritems - push_items) * sizeof(u64));
         }
-        src->header.nritems -= push_items;
-        dst->header.nritems += push_items;
-
+        btrfs_set_header_nritems(&src->header, src_nritems - push_items);
+        btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
         BUG_ON(list_empty(&src_buf->dirty));
         BUG_ON(list_empty(&dst_buf->dirty));
         return ret;
@@ -573,8 +583,8 @@ static int balance_node_right(struct ctree_root *root,
         int dst_nritems;
         int ret = 0;
 
-        src_nritems = src->header.nritems;
-        dst_nritems = dst->header.nritems;
+        src_nritems = btrfs_header_nritems(&src->header);
+        dst_nritems = btrfs_header_nritems(&dst->header);
         push_items = NODEPTRS_PER_BLOCK - dst_nritems;
         if (push_items <= 0) {
                 return 1;
@@ -596,8 +606,8 @@ static int balance_node_right(struct ctree_root *root,
         memcpy(dst->blockptrs, src->blockptrs + src_nritems - push_items,
                 push_items * sizeof(u64));
 
-        src->header.nritems -= push_items;
-        dst->header.nritems += push_items;
+        btrfs_set_header_nritems(&src->header, src_nritems - push_items);
+        btrfs_set_header_nritems(&dst->header, dst_nritems + push_items);
 
         BUG_ON(list_empty(&src_buf->dirty));
         BUG_ON(list_empty(&dst_buf->dirty));
@@ -625,12 +635,13 @@ static int insert_new_root(struct ctree_root *root,
         t = alloc_free_block(root);
         c = &t->node;
         memset(c, 0, sizeof(c));
-        c->header.nritems = 1;
-        c->header.flags = node_level(level);
-        c->header.blocknr = t->blocknr;
-        c->header.parentid = root->node->node.header.parentid;
+        btrfs_set_header_nritems(&c->header, 1);
+        btrfs_set_header_level(&c->header, level);
+        btrfs_set_header_blocknr(&c->header, t->blocknr);
+        btrfs_set_header_parentid(&c->header,
+                               btrfs_header_parentid(&root->node->node.header));
         lower = &path->nodes[level-1]->node;
-        if (is_leaf(lower->header.flags))
+        if (btrfs_is_leaf(lower))
                 lower_key = &((struct leaf *)lower)->items[0].key;
         else
                 lower_key = lower->keys;
@@ -663,7 +674,7 @@ static int insert_ptr(struct ctree_root *root,
 
         BUG_ON(!path->nodes[level]);
         lower = &path->nodes[level]->node;
-        nritems = lower->header.nritems;
+        nritems = btrfs_header_nritems(&lower->header);
         if (slot > nritems)
                 BUG();
         if (nritems == NODEPTRS_PER_BLOCK)
@@ -676,7 +687,7 @@ static int insert_ptr(struct ctree_root *root,
         }
         memcpy(lower->keys + slot, key, sizeof(struct key));
         lower->blockptrs[slot] = blocknr;
-        lower->header.nritems++;
+        btrfs_set_header_nritems(&lower->header, nritems + 1);
         if (lower->keys[1].objectid == 0)
                         BUG();
         BUG_ON(list_empty(&path->nodes[level]->dirty));
@@ -702,6 +713,7 @@ static int split_node(struct ctree_root *root, struct ctree_path *path,
         int mid;
         int ret;
         int wret;
+        u32 c_nritems;
 
         t = path->nodes[level];
         c = &t->node;
@@ -711,18 +723,20 @@ static int split_node(struct ctree_root *root, struct ctree_path *path,
                 if (ret)
                         return ret;
         }
+        c_nritems = btrfs_header_nritems(&c->header);
         split_buffer = alloc_free_block(root);
         split = &split_buffer->node;
-        split->header.flags = c->header.flags;
-        split->header.blocknr = split_buffer->blocknr;
-        split->header.parentid = root->node->node.header.parentid;
-        mid = (c->header.nritems + 1) / 2;
+        btrfs_set_header_flags(&split->header, btrfs_header_flags(&c->header));
+        btrfs_set_header_blocknr(&split->header, split_buffer->blocknr);
+        btrfs_set_header_parentid(&split->header,
+                               btrfs_header_parentid(&root->node->node.header));
+        mid = (c_nritems + 1) / 2;
         memcpy(split->keys, c->keys + mid,
-                (c->header.nritems - mid) * sizeof(struct key));
+                (c_nritems - mid) * sizeof(struct key));
         memcpy(split->blockptrs, c->blockptrs + mid,
-                (c->header.nritems - mid) * sizeof(u64));
-        split->header.nritems = c->header.nritems - mid;
-        c->header.nritems = mid;
+                (c_nritems - mid) * sizeof(u64));
+        btrfs_set_header_nritems(&split->header, c_nritems - mid);
+        btrfs_set_header_nritems(&c->header, mid);
         ret = 0;
 
         BUG_ON(list_empty(&t->dirty));
@@ -781,13 +795,15 @@ static int push_leaf_right(struct ctree_root *root, struct ctree_path *path,
         int push_space = 0;
         int push_items = 0;
         struct item *item;
+        u32 left_nritems;
+        u32 right_nritems;
 
         slot = path->slots[1];
         if (!path->nodes[1]) {
                 return 1;
         }
         upper = path->nodes[1];
-        if (slot >= upper->node.header.nritems - 1) {
+        if (slot >= btrfs_header_nritems(&upper->node.header) - 1) {
                 return 1;
         }
         right_buf = read_tree_block(root, upper->node.blockptrs[slot + 1]);
@@ -806,7 +822,8 @@ static int push_leaf_right(struct ctree_root *root, struct ctree_path *path,
                 return 1;
         }
 
-        for (i = left->header.nritems - 1; i >= 0; i--) {
+        left_nritems = btrfs_header_nritems(&left->header);
+        for (i = left_nritems - 1; i >= 0; i--) {
                 item = left->items + i;
                 if (path->slots[0] == i)
                         push_space += data_size + sizeof(*item);
@@ -819,9 +836,10 @@ static int push_leaf_right(struct ctree_root *root, struct ctree_path *path,
                 tree_block_release(root, right_buf);
                 return 1;
         }
+        right_nritems = btrfs_header_nritems(&right->header);
         /* push left to right */
-        push_space = left->items[left->header.nritems - push_items].offset +
-                     left->items[left->header.nritems - push_items].size;
+        push_space = left->items[left_nritems - push_items].offset +
+                     left->items[left_nritems - push_items].size;
         push_space -= leaf_data_end(left);
         /* make room in the right data area */
         memmove(right->data + leaf_data_end(right) - push_space,
@@ -832,19 +850,21 @@ static int push_leaf_right(struct ctree_root *root, struct ctree_path *path,
                 left->data + leaf_data_end(left),
                 push_space);
         memmove(right->items + push_items, right->items,
-                right->header.nritems * sizeof(struct item));
+                right_nritems * sizeof(struct item));
         /* copy the items from left to right */
-        memcpy(right->items, left->items + left->header.nritems - push_items,
+        memcpy(right->items, left->items + left_nritems - push_items,
                 push_items * sizeof(struct item));
 
         /* update the item pointers */
-        right->header.nritems += push_items;
+        right_nritems += push_items;
+        btrfs_set_header_nritems(&right->header, right_nritems);
         push_space = LEAF_DATA_SIZE;
-        for (i = 0; i < right->header.nritems; i++) {
+        for (i = 0; i < right_nritems; i++) {
                 right->items[i].offset = push_space - right->items[i].size;
                 push_space = right->items[i].offset;
         }
-        left->header.nritems -= push_items;
+        left_nritems -= push_items;
+        btrfs_set_header_nritems(&left->header, left_nritems);
 
         BUG_ON(list_empty(&left_buf->dirty));
         BUG_ON(list_empty(&right_buf->dirty));
@@ -853,8 +873,8 @@ static int push_leaf_right(struct ctree_root *root, struct ctree_path *path,
         BUG_ON(list_empty(&upper->dirty));
 
         /* then fixup the leaf pointer in the path */
-        if (path->slots[0] >= left->header.nritems) {
-                path->slots[0] -= left->header.nritems;
+        if (path->slots[0] >= left_nritems) {
+                path->slots[0] -= left_nritems;
                 tree_block_release(root, path->nodes[0]);
                 path->nodes[0] = right_buf;
                 path->slots[1] += 1;
@@ -880,7 +900,7 @@ static int push_leaf_left(struct ctree_root *root, struct ctree_path *path,
         int push_space = 0;
         int push_items = 0;
         struct item *item;
-        int old_left_nritems;
+        u32 old_left_nritems;
         int ret = 0;
         int wret;
 
@@ -908,7 +928,7 @@ static int push_leaf_left(struct ctree_root *root, struct ctree_path *path,
                 return 1;
         }
 
-        for (i = 0; i < right->header.nritems; i++) {
+        for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
                 item = right->items + i;
                 if (path->slots[0] == i)
                         push_space += data_size + sizeof(*item);
@@ -922,31 +942,34 @@ static int push_leaf_left(struct ctree_root *root, struct ctree_path *path,
                 return 1;
         }
         /* push data from right to left */
-        memcpy(left->items + left->header.nritems,
+        memcpy(left->items + btrfs_header_nritems(&left->header),
                 right->items, push_items * sizeof(struct item));
         push_space = LEAF_DATA_SIZE - right->items[push_items -1].offset;
         memcpy(left->data + leaf_data_end(left) - push_space,
                 right->data + right->items[push_items - 1].offset,
                 push_space);
-        old_left_nritems = left->header.nritems;
+        old_left_nritems = btrfs_header_nritems(&left->header);
         BUG_ON(old_left_nritems < 0);
 
         for(i = old_left_nritems; i < old_left_nritems + push_items; i++) {
                 left->items[i].offset -= LEAF_DATA_SIZE -
                         left->items[old_left_nritems -1].offset;
         }
-        left->header.nritems += push_items;
+        btrfs_set_header_nritems(&left->header, old_left_nritems + push_items);
 
         /* fixup right node */
         push_space = right->items[push_items-1].offset - leaf_data_end(right);
         memmove(right->data + LEAF_DATA_SIZE - push_space, right->data +
                 leaf_data_end(right), push_space);
         memmove(right->items, right->items + push_items,
-                (right->header.nritems - push_items) * sizeof(struct item));
-        right->header.nritems -= push_items;
+                (btrfs_header_nritems(&right->header) - push_items) *
+                sizeof(struct item));
+        btrfs_set_header_nritems(&right->header,
+                                 btrfs_header_nritems(&right->header) -
+                                 push_items);
         push_space = LEAF_DATA_SIZE;
 
-        for (i = 0; i < right->header.nritems; i++) {
+        for (i = 0; i < btrfs_header_nritems(&right->header); i++) {
                 right->items[i].offset = push_space - right->items[i].size;
                 push_space = right->items[i].offset;
         }
@@ -983,7 +1006,7 @@ static int split_leaf(struct ctree_root *root, struct ctree_path *path,
 {
         struct tree_buffer *l_buf;
         struct leaf *l;
-        int nritems;
+        u32 nritems;
         int mid;
         int slot;
         struct leaf *right;
@@ -1008,7 +1031,7 @@ static int split_leaf(struct ctree_root *root, struct ctree_path *path,
                         return ret;
         }
         slot = path->slots[0];
-        nritems = l->header.nritems;
+        nritems = btrfs_header_nritems(&l->header);
         mid = (nritems + 1)/ 2;
         right_buffer = alloc_free_block(root);
         BUG_ON(!right_buffer);
@@ -1026,10 +1049,11 @@ static int split_leaf(struct ctree_root *root, struct ctree_path *path,
                         LEAF_DATA_SIZE)
                         BUG();
         }
-        right->header.nritems = nritems - mid;
-        right->header.blocknr = right_buffer->blocknr;
-        right->header.flags = node_level(0);
-        right->header.parentid = root->node->node.header.parentid;
+        btrfs_set_header_nritems(&right->header, nritems - mid);
+        btrfs_set_header_blocknr(&right->header, right_buffer->blocknr);
+        btrfs_set_header_level(&right->header, 0);
+        btrfs_set_header_parentid(&right->header,
+                               btrfs_header_parentid(&root->node->node.header));
         data_copy_size = l->items[mid].offset + l->items[mid].size -
                          leaf_data_end(l);
         memcpy(right->items, l->items + mid,
@@ -1039,10 +1063,10 @@ static int split_leaf(struct ctree_root *root, struct ctree_path *path,
         rt_data_off = LEAF_DATA_SIZE -
                      (l->items[mid].offset + l->items[mid].size);
 
-        for (i = 0; i < right->header.nritems; i++)
+        for (i = 0; i < btrfs_header_nritems(&right->header); i++)
                 right->items[i].offset += rt_data_off;
 
-        l->header.nritems = mid;
+        btrfs_set_header_nritems(&l->header, mid);
         ret = 0;
         wret = insert_ptr(root, path, &right->items[0].key,
                           right_buffer->blocknr, path->slots[1] + 1, 1);
@@ -1074,7 +1098,7 @@ int insert_item(struct ctree_root *root, struct key *key,
         int slot_orig;
         struct leaf *leaf;
         struct tree_buffer *leaf_buf;
-        unsigned int nritems;
+        u32 nritems;
         unsigned int data_end;
         struct ctree_path path;
 
@@ -1094,7 +1118,7 @@ int insert_item(struct ctree_root *root, struct key *key,
         leaf_buf = path.nodes[0];
         leaf = &leaf_buf->leaf;
 
-        nritems = leaf->header.nritems;
+        nritems = btrfs_header_nritems(&leaf->header);
         data_end = leaf_data_end(leaf);
 
         if (leaf_free_space(leaf) <  sizeof(struct item) + data_size)
@@ -1128,7 +1152,7 @@ int insert_item(struct ctree_root *root, struct key *key,
         leaf->items[slot].offset = data_end - data_size;
         leaf->items[slot].size = data_size;
         memcpy(leaf->data + data_end - data_size, data, data_size);
-        leaf->header.nritems += 1;
+        btrfs_set_header_nritems(&leaf->header, nritems + 1);
 
         ret = 0;
         if (slot == 0)
@@ -1155,12 +1179,12 @@ static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level,
 {
         struct node *node;
         struct tree_buffer *parent = path->nodes[level];
-        int nritems;
+        u32 nritems;
         int ret = 0;
         int wret;
 
         node = &parent->node;
-        nritems = node->header.nritems;
+        nritems = btrfs_header_nritems(&node->header);
         if (slot != nritems -1) {
                 memmove(node->keys + slot, node->keys + slot + 1,
                         sizeof(struct key) * (nritems - slot - 1));
@@ -1168,11 +1192,12 @@ static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level,
                         node->blockptrs + slot + 1,
                         sizeof(u64) * (nritems - slot - 1));
         }
-        node->header.nritems--;
-        if (node->header.nritems == 0 && parent == root->node) {
-                BUG_ON(node_level(root->node->node.header.flags) != 1);
+        nritems--;
+        btrfs_set_header_nritems(&node->header, nritems);
+        if (nritems == 0 && parent == root->node) {
+                BUG_ON(btrfs_header_level(&root->node->node.header) != 1);
                 /* just turn the root into a leaf and break */
-                root->node->node.header.flags = node_level(0);
+                btrfs_set_header_level(&root->node->node.header, 0);
         } else if (slot == 0) {
                 wret = fixup_low_keys(root, path, node->keys, level + 1);
                 if (wret)
@@ -1195,30 +1220,33 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
         int dsize;
         int ret = 0;
         int wret;
+        u32 nritems;
 
         leaf_buf = path->nodes[0];
         leaf = &leaf_buf->leaf;
         slot = path->slots[0];
         doff = leaf->items[slot].offset;
         dsize = leaf->items[slot].size;
+        nritems = btrfs_header_nritems(&leaf->header);
 
-        if (slot != leaf->header.nritems - 1) {
+        if (slot != nritems - 1) {
                 int i;
                 int data_end = leaf_data_end(leaf);
                 memmove(leaf->data + data_end + dsize,
                         leaf->data + data_end,
                         doff - data_end);
-                for (i = slot + 1; i < leaf->header.nritems; i++)
+                for (i = slot + 1; i < nritems; i++)
                         leaf->items[i].offset += dsize;
                 memmove(leaf->items + slot, leaf->items + slot + 1,
                         sizeof(struct item) *
-                        (leaf->header.nritems - slot - 1));
+                        (nritems - slot - 1));
         }
-        leaf->header.nritems -= 1;
+        btrfs_set_header_nritems(&leaf->header, nritems - 1);
+        nritems--;
         /* delete the leaf if we've emptied it */
-        if (leaf->header.nritems == 0) {
+        if (nritems == 0) {
                 if (leaf_buf == root->node) {
-                        leaf->header.flags = node_level(0);
+                        btrfs_set_header_level(&leaf->header, 0);
                         BUG_ON(list_empty(&leaf_buf->dirty));
                 } else {
                         clean_tree_block(root, leaf_buf);
@@ -1230,7 +1258,7 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
                                 ret = wret;
                 }
         } else {
-                int used = leaf_space_used(leaf, 0, leaf->header.nritems);
+                int used = leaf_space_used(leaf, 0, nritems);
                 if (slot == 0) {
                         wret = fixup_low_keys(root, path,
                                                    &leaf->items[0].key, 1);
@@ -1251,12 +1279,12 @@ int del_item(struct ctree_root *root, struct ctree_path *path)
                         if (wret < 0)
                                 ret = wret;
                         if (path->nodes[0] == leaf_buf &&
-                            leaf->header.nritems) {
+                            btrfs_header_nritems(&leaf->header)) {
                                 wret = push_leaf_right(root, path, 1);
                                 if (wret < 0)
                                         ret = wret;
                         }
-                        if (leaf->header.nritems == 0) {
+                        if (btrfs_header_nritems(&leaf->header) == 0) {
                                 u64 blocknr = leaf_buf->blocknr;
                                 clean_tree_block(root, leaf_buf);
                                 wret = del_ptr(root, path, 1, slot);
@@ -1292,7 +1320,7 @@ int next_leaf(struct ctree_root *root, struct ctree_path *path)
                         return 1;
                 slot = path->slots[level] + 1;
                 c = path->nodes[level];
-                if (slot >= c->node.header.nritems) {
+                if (slot >= btrfs_header_nritems(&c->node.header)) {
                         level++;
                         continue;
                 }
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 518326fa3694..60c21fe1566a 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -35,13 +35,10 @@ struct header {
         /* generation flags to be added */
 } __attribute__ ((__packed__));
 
+#define MAX_LEVEL 8
 #define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct header)) / \
                             (sizeof(struct key) + sizeof(u64)))
 
-#define MAX_LEVEL 8
-#define node_level(f) ((f) & (MAX_LEVEL-1))
-#define is_leaf(f) (node_level(f) == 0)
-
 struct tree_buffer;
 
 /*
@@ -144,6 +141,64 @@ struct ctree_path {
         int slots[MAX_LEVEL];
 };
 
+static inline u64 btrfs_header_blocknr(struct header *h)
+{
+        return h->blocknr;
+}
+
+static inline void btrfs_set_header_blocknr(struct header *h, u64 blocknr)
+{
+        h->blocknr = blocknr;
+}
+
+static inline u64 btrfs_header_parentid(struct header *h)
+{
+        return h->parentid;
+}
+
+static inline void btrfs_set_header_parentid(struct header *h, u64 parentid)
+{
+        h->parentid = parentid;
+}
+
+static inline u32 btrfs_header_nritems(struct header *h)
+{
+        return h->nritems;
+}
+
+static inline void btrfs_set_header_nritems(struct header *h, u32 val)
+{
+        h->nritems = val;
+}
+
+static inline u32 btrfs_header_flags(struct header *h)
+{
+        return h->flags;
+}
+
+static inline void btrfs_set_header_flags(struct header *h, u32 val)
+{
+        h->flags = val;
+}
+
+static inline int btrfs_header_level(struct header *h)
+{
+        return btrfs_header_flags(h) & (MAX_LEVEL - 1);
+}
+
+static inline void btrfs_set_header_level(struct header *h, int level)
+{
+        u32 flags;
+        BUG_ON(level > MAX_LEVEL);
+        flags = btrfs_header_flags(h) & ~(MAX_LEVEL - 1);
+        btrfs_set_header_flags(h, flags | level);
+}
+
+static inline int btrfs_is_leaf(struct node *n)
+{
+        return (btrfs_header_level(&n->header) == 0);
+}
+
 struct tree_buffer *alloc_free_block(struct ctree_root *root);
 int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf);
 int free_extent(struct ctree_root *root, u64 blocknr, u64 num_blocks);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c9201ec81fef..065e888d2c0b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -15,9 +15,10 @@ int cache_max = 10000;
 
 static int check_tree_block(struct ctree_root *root, struct tree_buffer *buf)
 {
-        if (buf->blocknr != buf->node.header.blocknr)
+        if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
                 BUG();
-        if (root->node && buf->node.header.parentid != root->node->node.header.parentid)
+        if (root->node && btrfs_header_parentid(&buf->node.header) !=
+            btrfs_header_parentid(&root->node->node.header))
                 BUG();
         return 0;
 }
@@ -129,7 +130,7 @@ int write_tree_block(struct ctree_root *root, struct tree_buffer *buf)
         loff_t offset = blocknr * CTREE_BLOCKSIZE;
         int ret;
 
-        if (buf->blocknr != buf->node.header.blocknr)
+        if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
                 BUG();
         ret = pwrite(root->fp, &buf->node, CTREE_BLOCKSIZE, offset);
         if (ret != CTREE_BLOCKSIZE)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e7b8a70b5e52..524c11fea24a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -79,10 +79,10 @@ int btrfs_inc_ref(struct ctree_root *root, struct tree_buffer *buf)
 
         if (root == root->extent_root)
                 return 0;
-        if (is_leaf(buf->node.header.flags))
+        if (btrfs_is_leaf(&buf->node))
                 return 0;
 
-        for (i = 0; i < buf->node.header.nritems; i++) {
+        for (i = 0; i < btrfs_header_nritems(&buf->node.header); i++) {
                 blocknr = buf->node.blockptrs[i];
                 inc_block_ref(root, blocknr);
         }
@@ -119,7 +119,8 @@ static int finish_current_insert(struct ctree_root *extent_root)
         int ret;
 
         extent_item.refs = 1;
-        extent_item.owner = extent_root->node->node.header.parentid;
+        extent_item.owner =
+                btrfs_header_parentid(&extent_root->node->node.header);
         ins.offset = 1;
         ins.flags = 0;
 
@@ -269,7 +270,7 @@ static int find_free_extent(struct ctree_root *orig_root, u64 num_blocks,
         struct ctree_root * root = orig_root->extent_root;
         int total_needed = num_blocks;
 
-        total_needed += (node_level(root->node->node.header.flags) + 1) * 3;
+        total_needed += (btrfs_header_level(&root->node->node.header) + 1) * 3;
         if (root->last_insert.objectid > search_start)
                 search_start = root->last_insert.objectid;
 check_failed:
@@ -288,7 +289,7 @@ check_failed:
         while (1) {
                 l = &path.nodes[0]->leaf;
                 slot = path.slots[0];
-                if (slot >= l->header.nritems) {
+                if (slot >= btrfs_header_nritems(&l->header)) {
                         ret = next_leaf(root, &path);
                         if (ret == 0)
                                 continue;
@@ -404,7 +405,7 @@ struct tree_buffer *alloc_free_block(struct ctree_root *root)
         struct tree_buffer *buf;
 
         ret = alloc_extent(root, 1, 0, (unsigned long)-1,
-                           root->node->node.header.parentid,
+                           btrfs_header_parentid(&root->node->node.header),
                            &ins);
         if (ret) {
                 BUG();
@@ -429,7 +430,8 @@ int walk_down_tree(struct ctree_root *root, struct ctree_path *path, int *level)
                 goto out;
         while(*level > 0) {
                 cur = path->nodes[*level];
-                if (path->slots[*level] >= cur->node.header.nritems)
+                if (path->slots[*level] >=
+                    btrfs_header_nritems(&cur->node.header))
                         break;
                 blocknr = cur->node.blockptrs[path->slots[*level]];
                 ret = lookup_block_ref(root, blocknr, &refs);
@@ -444,7 +446,7 @@ int walk_down_tree(struct ctree_root *root, struct ctree_path *path, int *level)
                 if (path->nodes[*level-1])
                         tree_block_release(root, path->nodes[*level-1]);
                 path->nodes[*level-1] = next;
-                *level = node_level(next->node.header.flags);
+                *level = btrfs_header_level(&next->node.header);
                 path->slots[*level] = 0;
         }
 out:
@@ -463,7 +465,8 @@ int walk_up_tree(struct ctree_root *root, struct ctree_path *path, int *level)
         int ret;
         for(i = *level; i < MAX_LEVEL - 1 && path->nodes[i]; i++) {
                 slot = path->slots[i];
-                if (slot < path->nodes[i]->node.header.nritems - 1) {
+                if (slot <
+                    btrfs_header_nritems(&path->nodes[i]->node.header)- 1) {
                         path->slots[i]++;
                         *level = i;
                         return 0;
@@ -489,7 +492,7 @@ int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
 
         init_path(&path);
 
-        level = node_level(snap->node.header.flags);
+        level = btrfs_header_level(&snap->node.header);
         orig_level = level;
         path.nodes[level] = snap;
         path.slots[level] = 0;
@@ -509,33 +512,3 @@ int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
 
         return 0;
 }
-
-
-#if 0
-int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)
-{
-        int ret;
-        int level;
-        int refs;
-        u64 blocknr = snap->blocknr;
-
-        level = node_level(snap->node.header.flags);
-        ret = lookup_block_ref(root, snap->blocknr, &refs);
-        BUG_ON(ret);
-        if (refs == 1 && level != 0) {
-                struct node *n = &snap->node;
-                struct tree_buffer *b;
-                int i;
-                for (i = 0; i < n->header.nritems; i++) {
-                        b = read_tree_block(root, n->blockptrs[i]);
-                        /* FIXME, don't recurse here */
-                        ret = btrfs_drop_snapshot(root, b);
-                        BUG_ON(ret);
-                        tree_block_release(root, b);
-                }
-        }
-        ret = free_extent(root, blocknr, 1);
-        BUG_ON(ret);
-        return 0;
-}
-#endif
diff --git a/fs/btrfs/mkfs.c b/fs/btrfs/mkfs.c
index fd4e5dea7e1b..b2ba94696297 100644
--- a/fs/btrfs/mkfs.c
+++ b/fs/btrfs/mkfs.c
@@ -34,15 +34,15 @@ int mkfs(int fd)
 
         /* create leaves for the tree root and extent root */
         memset(&empty_leaf, 0, sizeof(empty_leaf));
-        empty_leaf.header.parentid = 1;
-        empty_leaf.header.blocknr = 17;
+        btrfs_set_header_parentid(&empty_leaf.header, 1);
+        btrfs_set_header_blocknr(&empty_leaf.header, 17);
         ret = pwrite(fd, &empty_leaf, sizeof(empty_leaf), 17 * CTREE_BLOCKSIZE);
         if (ret != sizeof(empty_leaf))
                 return -1;
 
-        empty_leaf.header.parentid = 2;
-        empty_leaf.header.blocknr = 18;
-        empty_leaf.header.nritems = 3;
+        btrfs_set_header_parentid(&empty_leaf.header, 2);
+        btrfs_set_header_blocknr(&empty_leaf.header, 18);
+        btrfs_set_header_nritems(&empty_leaf.header, 3);
 
         /* item1, reserve blocks 0-16 */
         item.key.objectid = 0;
diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index e32a959dd3e5..7df16b1e4733 100644
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -8,11 +8,11 @@
 void print_leaf(struct leaf *l)
 {
         int i;
-        int nr = l->header.nritems;
+        u32 nr = btrfs_header_nritems(&l->header);
         struct item *item;
         struct extent_item *ei;
-        printf("leaf %Lu total ptrs %d free space %d\n", l->header.blocknr, nr,
-               leaf_free_space(l));
+        printf("leaf %Lu total ptrs %d free space %d\n",
+                btrfs_header_blocknr(&l->header), nr, leaf_free_space(l));
         fflush(stdout);
         for (i = 0 ; i < nr ; i++) {
                 item = l->items + i;
@@ -32,22 +32,20 @@ void print_leaf(struct leaf *l)
 void print_tree(struct ctree_root *root, struct tree_buffer *t)
 {
         int i;
-        int nr;
+        u32 nr;
         struct node *c;
 
         if (!t)
                 return;
         c = &t->node;
-        nr = c->header.nritems;
-        if (c->header.blocknr != t->blocknr)
-                BUG();
-        if (is_leaf(c->header.flags)) {
+        nr = btrfs_header_nritems(&c->header);
+        if (btrfs_is_leaf(c)) {
                 print_leaf((struct leaf *)c);
                 return;
         }
         printf("node %Lu level %d total ptrs %d free spc %u\n", t->blocknr,
-                node_level(c->header.flags), c->header.nritems,
-                (u32)NODEPTRS_PER_BLOCK - c->header.nritems);
+                btrfs_header_level(&c->header), nr,
+                (u32)NODEPTRS_PER_BLOCK - nr);
         fflush(stdout);
         for (i = 0; i < nr; i++) {
                 printf("\tkey %d (%Lu %u %Lu) block %Lu\n",
@@ -60,11 +58,11 @@ void print_tree(struct ctree_root *root, struct tree_buffer *t)
                 struct tree_buffer *next_buf = read_tree_block(root,
                                                             c->blockptrs[i]);
                 struct node *next = &next_buf->node;
-                if (is_leaf(next->header.flags) &&
-                    node_level(c->header.flags) != 1)
+                if (btrfs_is_leaf(next) &&
+                    btrfs_header_level(&c->header) != 1)
                         BUG();
-                if (node_level(next->header.flags) !=
-                        node_level(c->header.flags) - 1)
+                if (btrfs_header_level(&next->header) !=
+                        btrfs_header_level(&c->header) - 1)
                         BUG();
                 print_tree(root, next_buf);
                 tree_block_release(root, next_buf);
diff --git a/fs/btrfs/quick-test.c b/fs/btrfs/quick-test.c
index ccca9b2c14a3..07fd71b77627 100644
--- a/fs/btrfs/quick-test.c
+++ b/fs/btrfs/quick-test.c
@@ -71,9 +71,10 @@ int main(int ac, char **av) {
         close_ctree(root, &super);
         root = open_ctree("dbfile", &super);
         printf("node %p level %d total ptrs %d free spc %lu\n", root->node,
-                node_level(root->node->node.header.flags),
-                root->node->node.header.nritems,
-                NODEPTRS_PER_BLOCK - root->node->node.header.nritems);
+                btrfs_header_level(&root->node->node.header),
+                btrfs_header_nritems(&root->node->node.header),
+                NODEPTRS_PER_BLOCK -
+                btrfs_header_nritems(&root->node->node.header));
         printf("all searches good, deleting some items\n");
         i = 0;
         srand(55);
@@ -126,7 +127,8 @@ int main(int ac, char **av) {
                 release_path(root, &path);
         }
         printf("starting big long delete run\n");
-        while(root->node && root->node->node.header.nritems > 0) {
+        while(root->node &&
+              btrfs_header_nritems(&root->node->node.header) > 0) {
                 struct leaf *leaf;
                 int slot;
                 ins.objectid = (u64)-1;
@@ -137,7 +139,7 @@ int main(int ac, char **av) {
 
                 leaf = &path.nodes[0]->leaf;
                 slot = path.slots[0];
-                if (slot != leaf->header.nritems)
+                if (slot != btrfs_header_nritems(&leaf->header))
                         BUG();
                 while(path.slots[0] > 0) {
                         path.slots[0] -= 1;
diff --git a/fs/btrfs/random-test.c b/fs/btrfs/random-test.c
index 7b37b6bae105..5d99b730a69c 100644
--- a/fs/btrfs/random-test.c
+++ b/fs/btrfs/random-test.c
@@ -358,8 +358,8 @@ int main(int ac, char **av)
                 }
                 if (i && i % 5000 == 0) {
                         printf("open & close, root level %d nritems %d\n",
-                                node_level(root->node->node.header.flags),
-                                root->node->node.header.nritems);
+                                btrfs_header_level(&root->node->node.header),
+                                btrfs_header_nritems(&root->node->node.header));
                         close_ctree(root, &super);
                         root = open_ctree("dbfile", &super);
                 }