ocfs2: Make ocfs2_extent_tree the first-class representation of a tree.
We now have three different kinds of extent trees in ocfs2: inode data
(dinode), extended attributes (xattr_tree), and extended attribute
values (xattr_value). There is a nice abstraction for them,
ocfs2_extent_tree, but it is hidden in alloc.c. All the calling
functions have to pick amongst a varied API and pass in type bits and
often extraneous pointers.
A better way is to make ocfs2_extent_tree a first-class object.
Everyone converts their object to an ocfs2_extent_tree() via the
ocfs2_get_*_extent_tree() calls, then uses the ocfs2_extent_tree for all
tree calls to alloc.c.
This simplifies a lot of callers, making for readability. It also
provides an easy way to add additional extent tree types, as they only
need to be defined in alloc.c with a ocfs2_get_<new>_extent_tree()
function.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
index 5cc9a83..35ad07f 100644
--- a/fs/ocfs2/alloc.h
+++ b/fs/ocfs2/alloc.h
@@ -26,46 +26,66 @@
#ifndef OCFS2_ALLOC_H
#define OCFS2_ALLOC_H
-enum ocfs2_extent_tree_type {
- OCFS2_DINODE_EXTENT = 0,
- OCFS2_XATTR_VALUE_EXTENT,
- OCFS2_XATTR_TREE_EXTENT,
-};
/*
* For xattr tree leaf, we limit the leaf byte size to be 64K.
*/
#define OCFS2_MAX_XATTR_TREE_LEAF_SIZE 65536
+/*
+ * ocfs2_extent_tree and ocfs2_extent_tree_operations are used to abstract
+ * the b-tree operations in ocfs2. Now all the b-tree operations are not
+ * limited to ocfs2_dinode only. Any data which need to allocate clusters
+ * to store can use b-tree. And it only needs to implement its ocfs2_extent_tree
+ * and operation.
+ *
+ * ocfs2_extent_tree becomes the first-class object for extent tree
+ * manipulation. Callers of the alloc.c code need to fill it via one of
+ * the ocfs2_get_*_extent_tree() operations below.
+ *
+ * ocfs2_extent_tree contains info for the root of the b-tree, it must have a
+ * root ocfs2_extent_list and a root_bh so that they can be used in the b-tree
+ * functions.
+ * ocfs2_extent_tree_operations abstract the normal operations we do for
+ * the root of extent b-tree.
+ */
+struct ocfs2_extent_tree_operations;
+struct ocfs2_extent_tree {
+ struct ocfs2_extent_tree_operations *et_ops;
+ struct buffer_head *et_root_bh;
+ struct ocfs2_extent_list *et_root_el;
+ void *et_object;
+ unsigned int et_max_leaf_clusters;
+};
+
+/*
+ * ocfs2_*_get_extent_tree() will fill an ocfs2_extent_tree from the
+ * specified object buffer. The bh is referenced until
+ * ocfs2_put_extent_tree().
+ */
+void ocfs2_get_dinode_extent_tree(struct ocfs2_extent_tree *et,
+ struct inode *inode,
+ struct buffer_head *bh);
+void ocfs2_get_xattr_tree_extent_tree(struct ocfs2_extent_tree *et,
+ struct inode *inode,
+ struct buffer_head *bh);
+void ocfs2_get_xattr_value_extent_tree(struct ocfs2_extent_tree *et,
+ struct inode *inode,
+ struct buffer_head *bh,
+ struct ocfs2_xattr_value_root *xv);
+void ocfs2_put_extent_tree(struct ocfs2_extent_tree *et);
+
struct ocfs2_alloc_context;
-int ocfs2_dinode_insert_extent(struct ocfs2_super *osb,
- handle_t *handle,
- struct inode *inode,
- struct buffer_head *root_bh,
- u32 cpos,
- u64 start_blk,
- u32 new_clusters,
- u8 flags,
- struct ocfs2_alloc_context *meta_ac);
-int ocfs2_xattr_value_insert_extent(struct ocfs2_super *osb,
- handle_t *handle,
- struct inode *inode,
- struct buffer_head *root_bh,
- u32 cpos,
- u64 start_blk,
- u32 new_clusters,
- u8 flags,
- struct ocfs2_alloc_context *meta_ac,
- struct ocfs2_xattr_value_root *xv);
-int ocfs2_xattr_tree_insert_extent(struct ocfs2_super *osb,
- handle_t *handle,
- struct inode *inode,
- struct buffer_head *root_bh,
- u32 cpos,
- u64 start_blk,
- u32 new_clusters,
- u8 flags,
- struct ocfs2_alloc_context *meta_ac);
+int ocfs2_insert_extent(struct ocfs2_super *osb,
+ handle_t *handle,
+ struct inode *inode,
+ struct ocfs2_extent_tree *et,
+ u32 cpos,
+ u64 start_blk,
+ u32 new_clusters,
+ u8 flags,
+ struct ocfs2_alloc_context *meta_ac);
+
enum ocfs2_alloc_restarted {
RESTART_NONE = 0,
RESTART_TRANS,
@@ -76,32 +96,25 @@
u32 *logical_offset,
u32 clusters_to_add,
int mark_unwritten,
- struct buffer_head *root_bh,
- struct ocfs2_extent_list *root_el,
+ struct ocfs2_extent_tree *et,
handle_t *handle,
struct ocfs2_alloc_context *data_ac,
struct ocfs2_alloc_context *meta_ac,
- enum ocfs2_alloc_restarted *reason_ret,
- enum ocfs2_extent_tree_type type,
- void *private);
+ enum ocfs2_alloc_restarted *reason_ret);
struct ocfs2_cached_dealloc_ctxt;
-int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
+int ocfs2_mark_extent_written(struct inode *inode,
+ struct ocfs2_extent_tree *et,
handle_t *handle, u32 cpos, u32 len, u32 phys,
struct ocfs2_alloc_context *meta_ac,
- struct ocfs2_cached_dealloc_ctxt *dealloc,
- enum ocfs2_extent_tree_type et_type,
- void *private);
-int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
+ struct ocfs2_cached_dealloc_ctxt *dealloc);
+int ocfs2_remove_extent(struct inode *inode,
+ struct ocfs2_extent_tree *et,
u32 cpos, u32 len, handle_t *handle,
struct ocfs2_alloc_context *meta_ac,
- struct ocfs2_cached_dealloc_ctxt *dealloc,
- enum ocfs2_extent_tree_type et_type,
- void *private);
+ struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_num_free_extents(struct ocfs2_super *osb,
struct inode *inode,
- struct buffer_head *root_bh,
- enum ocfs2_extent_tree_type et_type,
- void *private);
+ struct ocfs2_extent_tree *et);
/*
* how many new metadata chunks would an allocation need at maximum?