Btrfs: Add backing store, memory management
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
new file mode 100644
index 0000000..586bf18
--- /dev/null
+++ b/fs/btrfs/ctree.h
@@ -0,0 +1,62 @@
+#ifndef __CTREE__
+#define __CTREE__
+
+#define CTREE_BLOCKSIZE 4096
+
+struct key {
+ u64 objectid;
+ u32 flags;
+ u64 offset;
+} __attribute__ ((__packed__));
+
+struct header {
+ u64 fsid[2]; /* FS specific uuid */
+ u64 blocknr;
+ u64 parentid;
+ u32 csum;
+ u32 ham;
+ u16 nritems;
+ u16 flags;
+} __attribute__ ((__packed__));
+
+#define NODEPTRS_PER_BLOCK ((CTREE_BLOCKSIZE - sizeof(struct header)) / \
+ (sizeof(struct key) + sizeof(u64)))
+
+#define LEVEL_BITS 3
+#define MAX_LEVEL (1 << LEVEL_BITS)
+#define node_level(f) ((f) & (MAX_LEVEL-1))
+#define is_leaf(f) (node_level(f) == 0)
+
+struct tree_buffer;
+struct ctree_root {
+ struct tree_buffer *node;
+ int fp;
+ struct radix_tree_root cache_radix;
+};
+
+struct item {
+ struct key key;
+ u16 offset;
+ u16 size;
+} __attribute__ ((__packed__));
+
+#define LEAF_DATA_SIZE (CTREE_BLOCKSIZE - sizeof(struct header))
+struct leaf {
+ struct header header;
+ union {
+ struct item items[LEAF_DATA_SIZE/sizeof(struct item)];
+ u8 data[CTREE_BLOCKSIZE-sizeof(struct header)];
+ };
+} __attribute__ ((__packed__));
+
+struct node {
+ struct header header;
+ struct key keys[NODEPTRS_PER_BLOCK];
+ u64 blockptrs[NODEPTRS_PER_BLOCK];
+} __attribute__ ((__packed__));
+
+struct ctree_path {
+ struct tree_buffer *nodes[MAX_LEVEL];
+ int slots[MAX_LEVEL];
+};
+#endif