1 files changed, 51 insertions, 16 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b3bc65b08c6a..ad2cbe63503c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -469,6 +469,15 @@ struct btrfs_root_item {
         u8 level;
 } __attribute__ ((__packed__));
 
+/*
+ * this is used for both forward and backward root refs
+ */
+struct btrfs_root_ref {
+        __le64 dirid;
+        __le64 sequence;
+        __le16 name_len;
+} __attribute__ ((__packed__));
+
 #define BTRFS_FILE_EXTENT_INLINE 0
 #define BTRFS_FILE_EXTENT_REG 1
 #define BTRFS_FILE_EXTENT_PREALLOC 2
@@ -814,27 +823,27 @@ struct btrfs_root {
  * the FS
  */
 #define BTRFS_INODE_ITEM_KEY            1
-#define BTRFS_INODE_REF_KEY             2
-#define BTRFS_XATTR_ITEM_KEY            8
-#define BTRFS_ORPHAN_ITEM_KEY           9
+#define BTRFS_INODE_REF_KEY             12
+#define BTRFS_XATTR_ITEM_KEY            24
+#define BTRFS_ORPHAN_ITEM_KEY           48
 /* reserve 2-15 close to the inode for later flexibility */
 
 /*
  * dir items are the name -> inode pointers in a directory.  There is one
  * for every name in a directory.
  */
-#define BTRFS_DIR_LOG_ITEM_KEY  14
-#define BTRFS_DIR_LOG_INDEX_KEY 15
-#define BTRFS_DIR_ITEM_KEY      16
-#define BTRFS_DIR_INDEX_KEY     17
+#define BTRFS_DIR_LOG_ITEM_KEY  60
+#define BTRFS_DIR_LOG_INDEX_KEY 72
+#define BTRFS_DIR_ITEM_KEY      84
+#define BTRFS_DIR_INDEX_KEY     96
 /*
  * extent data is for file data
  */
-#define BTRFS_EXTENT_DATA_KEY   18
+#define BTRFS_EXTENT_DATA_KEY   108
 /*
  * csum items have the checksums for data in the extents
  */
-#define BTRFS_CSUM_ITEM_KEY     19
+#define BTRFS_CSUM_ITEM_KEY     120
 
 
 /* reserve 21-31 for other file/dir stuff */
@@ -843,23 +852,37 @@ struct btrfs_root {
  * root items point to tree roots.  There are typically in the root
  * tree used by the super block to find all the other trees
  */
-#define BTRFS_ROOT_ITEM_KEY     32
+#define BTRFS_ROOT_ITEM_KEY     132
+
+/*
+ * root backrefs tie subvols and snapshots to the directory entries that
+ * reference them
+ */
+#define BTRFS_ROOT_BACKREF_KEY  144
+
+/*
+ * root refs make a fast index for listing all of the snapshots and
+ * subvolumes referenced by a given root.  They point directly to the
+ * directory item in the root that references the subvol
+ */
+#define BTRFS_ROOT_REF_KEY      156
+
 /*
  * extent items are in the extent map tree.  These record which blocks
  * are used, and how many references there are to each block
  */
-#define BTRFS_EXTENT_ITEM_KEY   33
-#define BTRFS_EXTENT_REF_KEY    34
+#define BTRFS_EXTENT_ITEM_KEY   168
+#define BTRFS_EXTENT_REF_KEY    180
 
 /*
  * block groups give us hints into the extent allocation trees.  Which
  * blocks are free etc etc
  */
-#define BTRFS_BLOCK_GROUP_ITEM_KEY 50
+#define BTRFS_BLOCK_GROUP_ITEM_KEY 192
 
-#define BTRFS_DEV_EXTENT_KEY    75
-#define BTRFS_DEV_ITEM_KEY      76
-#define BTRFS_CHUNK_ITEM_KEY    77
+#define BTRFS_DEV_EXTENT_KEY    204
+#define BTRFS_DEV_ITEM_KEY      216
+#define BTRFS_CHUNK_ITEM_KEY    228
 
 /*
  * string items are for debugging.  They just store a short string of
@@ -1274,6 +1297,13 @@ static inline void btrfs_set_item_key(struct extent_buffer *eb,
 
 BTRFS_SETGET_FUNCS(dir_log_end, struct btrfs_dir_log_item, end, 64);
 
+/*
+ * struct btrfs_root_ref
+ */
+BTRFS_SETGET_FUNCS(root_ref_dirid, struct btrfs_root_ref, dirid, 64);
+BTRFS_SETGET_FUNCS(root_ref_sequence, struct btrfs_root_ref, sequence, 64);
+BTRFS_SETGET_FUNCS(root_ref_name_len, struct btrfs_root_ref, name_len, 16);
+
 /* struct btrfs_dir_item */
 BTRFS_SETGET_FUNCS(dir_data_len, struct btrfs_dir_item, data_len, 16);
 BTRFS_SETGET_FUNCS(dir_type, struct btrfs_dir_item, type, 8);
@@ -1771,6 +1801,11 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
                         struct extent_buffer *node,
                         struct extent_buffer *parent);
 /* root-item.c */
+int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
+                       struct btrfs_root *tree_root,
+                       u64 root_id, u8 type, u64 ref_id,
+                       u64 dirid, u64 sequence,
+                       const char *name, int name_len);
 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                    struct btrfs_key *key);
 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root