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Btrfs: Change the super to point to a tree of trees to enable persistent snapshots

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2007-03-13 16:47:54 -04:00
committed by David Woodhouse
parent eaee50e881
commit 3768f3689f
10 changed files with 445 additions and 65 deletions
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123
fs/btrfs/ctree.h
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@@ -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 @@ struct btrfs_key {
* 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_header {
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_root {
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 btrfs_root {
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 @@ static inline int btrfs_is_leaf(struct btrfs_node *n)
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_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
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