ocfs2: Add refcount tree lock mechanism.

Implement locking around struct ocfs2_refcount_tree.  This protects
all read/write operations on refcount trees.  ocfs2_refcount_tree
has its own lock and its own caching_info, protecting buffers among
multiple nodes.

User must call ocfs2_lock_refcount_tree before his operation on
the tree and unlock it after that.

ocfs2_refcount_trees are referenced by the block number of the
refcount tree root block, So we create an rb-tree on the ocfs2_super
to look them up.

Signed-off-by: Tao Ma <tao.ma@oracle.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/ocfs2/refcounttree.h b/fs/ocfs2/refcounttree.h
index 9a3695cdbb53..2ea7fc52c23c 100644
--- a/fs/ocfs2/refcounttree.h
+++ b/fs/ocfs2/refcounttree.h
@@ -33,4 +33,11 @@ struct ocfs2_refcount_tree {
         struct super_block *rf_sb;
 };
 
+void ocfs2_purge_refcount_trees(struct ocfs2_super *osb);
+int ocfs2_lock_refcount_tree(struct ocfs2_super *osb, u64 ref_blkno, int rw,
+                             struct ocfs2_refcount_tree **tree,
+                             struct buffer_head **ref_bh);
+void ocfs2_unlock_refcount_tree(struct ocfs2_super *osb,
+                                struct ocfs2_refcount_tree *tree,
+                                int rw);
 #endif /* OCFS2_REFCOUNTTREE_H */