Btrfs: Change the super to point to a tree of trees to enable persistent snapshots
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5dfcc90..0968899 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -4,8 +4,13 @@
#include "list.h"
#include "kerncompat.h"
+#define BTRFS_MAGIC "_BtRfS_M"
#define BTRFS_BLOCKSIZE 1024
+#define BTRFS_ROOT_TREE_OBJECTID 1
+#define BTRFS_EXTENT_TREE_OBJECTID 2
+#define BTRFS_FS_TREE_OBJECTID 3
+
/*
* the key defines the order in the tree, and so it also defines (optimal)
* block layout. objectid corresonds to the inode number. The flags
@@ -36,7 +41,7 @@
* every tree block (leaf or node) starts with this header.
*/
struct btrfs_header {
- __le64 fsid[2]; /* FS specific uuid */
+ u8 fsid[16]; /* FS specific uuid */
__le64 blocknr; /* which block this node is supposed to live in */
__le64 parentid; /* objectid of the tree root */
__le32 csum;
@@ -52,6 +57,14 @@
struct btrfs_buffer;
+struct btrfs_root_item {
+ __le64 blocknr;
+ __le32 flags;
+ __le64 block_limit;
+ __le64 blocks_used;
+ __le32 refs;
+};
+
/*
* in ram representation of the tree. extent_root is used for all allocations
* and for the extent tree extent_root root. current_insert is used
@@ -61,6 +74,7 @@
struct btrfs_buffer *node;
struct btrfs_buffer *commit_root;
struct btrfs_root *extent_root;
+ struct btrfs_root *tree_root;
struct btrfs_key current_insert;
struct btrfs_key last_insert;
int fp;
@@ -69,28 +83,25 @@
struct list_head trans;
struct list_head cache;
int cache_size;
+ int ref_cows;
+ struct btrfs_root_item root_item;
+ struct btrfs_key root_key;
};
/*
- * describes a tree on disk
- */
-struct btrfs_root_info {
- u64 fsid[2]; /* FS specific uuid */
- u64 blocknr; /* blocknr of this block */
- u64 objectid; /* inode number of this root */
- u64 tree_root; /* the tree root block */
- u32 csum;
- u32 ham;
- u64 snapuuid[2]; /* root specific uuid */
-} __attribute__ ((__packed__));
-
-/*
* the super block basically lists the main trees of the FS
* it currently lacks any block count etc etc
*/
struct btrfs_super_block {
- struct btrfs_root_info root_info;
- struct btrfs_root_info extent_info;
+ u8 fsid[16]; /* FS specific uuid */
+ __le64 blocknr; /* this block number */
+ __le32 csum;
+ __le64 magic;
+ __le16 blocksize;
+ __le64 generation;
+ __le64 root;
+ __le64 total_blocks;
+ __le64 blocks_used;
} __attribute__ ((__packed__));
/*
@@ -317,6 +328,79 @@
return (btrfs_header_level(&n->header) == 0);
}
+static inline u64 btrfs_root_blocknr(struct btrfs_root_item *item)
+{
+ return le64_to_cpu(item->blocknr);
+}
+
+static inline void btrfs_set_root_blocknr(struct btrfs_root_item *item, u64 val)
+{
+ item->blocknr = cpu_to_le64(val);
+}
+
+static inline u32 btrfs_root_refs(struct btrfs_root_item *item)
+{
+ return le32_to_cpu(item->refs);
+}
+
+static inline void btrfs_set_root_refs(struct btrfs_root_item *item, u32 val)
+{
+ item->refs = cpu_to_le32(val);
+}
+
+static inline u64 btrfs_super_blocknr(struct btrfs_super_block *s)
+{
+ return le64_to_cpu(s->blocknr);
+}
+
+static inline void btrfs_set_super_blocknr(struct btrfs_super_block *s, u64 val)
+{
+ s->blocknr = cpu_to_le64(val);
+}
+
+static inline u64 btrfs_super_root(struct btrfs_super_block *s)
+{
+ return le64_to_cpu(s->root);
+}
+
+static inline void btrfs_set_super_root(struct btrfs_super_block *s, u64 val)
+{
+ s->root = cpu_to_le64(val);
+}
+
+static inline u64 btrfs_super_total_blocks(struct btrfs_super_block *s)
+{
+ return le64_to_cpu(s->total_blocks);
+}
+
+static inline void btrfs_set_super_total_blocks(struct btrfs_super_block *s,
+ u64 val)
+{
+ s->total_blocks = cpu_to_le64(val);
+}
+
+static inline u64 btrfs_super_blocks_used(struct btrfs_super_block *s)
+{
+ return le64_to_cpu(s->blocks_used);
+}
+
+static inline void btrfs_set_super_blocks_used(struct btrfs_super_block *s,
+ u64 val)
+{
+ s->blocks_used = cpu_to_le64(val);
+}
+
+static inline u16 btrfs_super_blocksize(struct btrfs_super_block *s)
+{
+ return le16_to_cpu(s->blocksize);
+}
+
+static inline void btrfs_set_super_blocksize(struct btrfs_super_block *s,
+ u16 val)
+{
+ s->blocksize = cpu_to_le16(val);
+}
+
struct btrfs_buffer *btrfs_alloc_free_block(struct btrfs_root *root);
int btrfs_inc_ref(struct btrfs_root *root, struct btrfs_buffer *buf);
int btrfs_free_extent(struct btrfs_root *root, u64 blocknr, u64 num_blocks);
@@ -331,4 +415,11 @@
int btrfs_leaf_free_space(struct btrfs_leaf *leaf);
int btrfs_drop_snapshot(struct btrfs_root *root, struct btrfs_buffer *snap);
int btrfs_finish_extent_commit(struct btrfs_root *root);
+int btrfs_del_root(struct btrfs_root *root, struct btrfs_key *key);
+int btrfs_insert_root(struct btrfs_root *root, struct btrfs_key *key,
+ struct btrfs_root_item *item);
+int btrfs_update_root(struct btrfs_root *root, struct btrfs_key *key,
+ struct btrfs_root_item *item);
+int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
+ struct btrfs_root_item *item, struct btrfs_key *key);
#endif