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>

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 @@ int ocfs2_add_clusters_in_btree(struct ocfs2_super *osb,
 				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?

fs/ocfs2/aops.c

@@ -1242,6 +1242,7 @@ static int ocfs2_write_cluster(struct address_space *mapping,
 	int ret, i, new, should_zero = 0;
 	u64 v_blkno, p_blkno;
 	struct inode *inode = mapping->host;
+	struct ocfs2_extent_tree et;
 
 	new = phys == 0 ? 1 : 0;
 	if (new || unwritten)
@@ -1276,10 +1277,11 @@ static int ocfs2_write_cluster(struct address_space *mapping,
 			goto out;
 		}
 	} else if (unwritten) {
-		ret = ocfs2_mark_extent_written(inode, wc->w_di_bh,
+		ocfs2_get_dinode_extent_tree(&et, inode, wc->w_di_bh);
+		ret = ocfs2_mark_extent_written(inode, &et,
 						wc->w_handle, cpos, 1, phys,
-						meta_ac, &wc->w_dealloc,
-						OCFS2_DINODE_EXTENT, NULL);
+						meta_ac, &wc->w_dealloc);
+		ocfs2_put_extent_tree(&et);
 		if (ret < 0) {
 			mlog_errno(ret);
 			goto out;
@@ -1666,6 +1668,7 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
 	struct ocfs2_alloc_context *data_ac = NULL;
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	handle_t *handle;
+	struct ocfs2_extent_tree et;
 
 	ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, di_bh);
 	if (ret) {
@@ -1719,10 +1722,11 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
 		     (long long)i_size_read(inode), le32_to_cpu(di->i_clusters),
 		     clusters_to_alloc, extents_to_split);
 
-		ret = ocfs2_lock_allocators(inode, wc->w_di_bh, &di->id2.i_list,
+		ocfs2_get_dinode_extent_tree(&et, inode, wc->w_di_bh);
+		ret = ocfs2_lock_allocators(inode, &et,
 					    clusters_to_alloc, extents_to_split,
-					    &data_ac, &meta_ac,
-					    OCFS2_DINODE_EXTENT, NULL);
+					    &data_ac, &meta_ac);
+		ocfs2_put_extent_tree(&et);
 		if (ret) {
 			mlog_errno(ret);
 			goto out;

fs/ocfs2/dir.c

@@ -1192,6 +1192,9 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 	struct buffer_head *dirdata_bh = NULL;
 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
 	handle_t *handle;
+	struct ocfs2_extent_tree et;
+
+	ocfs2_get_dinode_extent_tree(&et, dir, di_bh);
 
 	alloc = ocfs2_clusters_for_bytes(sb, bytes);
 
@@ -1305,8 +1308,8 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 	 * This should never fail as our extent list is empty and all
 	 * related blocks have been journaled already.
 	 */
-	ret = ocfs2_dinode_insert_extent(osb, handle, dir, di_bh, 0, blkno,
-					 len, 0, NULL);
+	ret = ocfs2_insert_extent(osb, handle, dir, &et, 0, blkno, len,
+				  0, NULL);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
@@ -1337,8 +1340,8 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 		}
 		blkno = ocfs2_clusters_to_blocks(dir->i_sb, bit_off);
 
-		ret = ocfs2_dinode_insert_extent(osb, handle, dir, di_bh, 1,
-						 blkno, len, 0, NULL);
+		ret = ocfs2_insert_extent(osb, handle, dir, &et, 1,
+					  blkno, len, 0, NULL);
 		if (ret) {
 			mlog_errno(ret);
 			goto out_commit;
@@ -1360,6 +1363,7 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
 
 	brelse(dirdata_bh);
 
+	ocfs2_put_extent_tree(&et);
 	return ret;
 }
 
@@ -1437,6 +1441,7 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
 	struct buffer_head *new_bh = NULL;
 	struct ocfs2_dir_entry * de;
 	struct super_block *sb = osb->sb;
+	struct ocfs2_extent_tree et;
 
 	mlog_entry_void();
 
@@ -1480,10 +1485,9 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
 	spin_lock(&OCFS2_I(dir)->ip_lock);
 	if (dir_i_size == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters)) {
 		spin_unlock(&OCFS2_I(dir)->ip_lock);
-		num_free_extents = ocfs2_num_free_extents(osb, dir,
-							  parent_fe_bh,
-							  OCFS2_DINODE_EXTENT,
-							  NULL);
+		ocfs2_get_dinode_extent_tree(&et, dir, parent_fe_bh);
+		num_free_extents = ocfs2_num_free_extents(osb, dir, &et);
+		ocfs2_put_extent_tree(&et);
 		if (num_free_extents < 0) {
 			status = num_free_extents;
 			mlog_errno(status);

fs/ocfs2/file.c

@@ -509,14 +509,17 @@ int ocfs2_add_inode_data(struct ocfs2_super *osb,
 			 struct ocfs2_alloc_context *meta_ac,
 			 enum ocfs2_alloc_restarted *reason_ret)
 {
-	struct ocfs2_dinode *fe = (struct ocfs2_dinode *) fe_bh->b_data;
-	struct ocfs2_extent_list *el = &fe->id2.i_list;
+	int ret;
+	struct ocfs2_extent_tree et;
 
-	return ocfs2_add_clusters_in_btree(osb, inode, logical_offset,
+	ocfs2_get_dinode_extent_tree(&et, inode, fe_bh);
+	ret = ocfs2_add_clusters_in_btree(osb, inode, logical_offset,
 					   clusters_to_add, mark_unwritten,
-					   fe_bh, el, handle,
-					   data_ac, meta_ac, reason_ret,
-					   OCFS2_DINODE_EXTENT, NULL);
+					   &et, handle,
+					   data_ac, meta_ac, reason_ret);
+	ocfs2_put_extent_tree(&et);
+
+	return ret;
 }
 
 static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
@@ -533,6 +536,7 @@ static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	enum ocfs2_alloc_restarted why;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_extent_tree et;
 
 	mlog_entry("(clusters_to_add = %u)\n", clusters_to_add);
 
@@ -564,9 +568,10 @@ static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
 	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
 	     (long long)i_size_read(inode), le32_to_cpu(fe->i_clusters),
 	     clusters_to_add);
-	status = ocfs2_lock_allocators(inode, bh, &fe->id2.i_list,
-				       clusters_to_add, 0, &data_ac,
-				       &meta_ac, OCFS2_DINODE_EXTENT, NULL);
+	ocfs2_get_dinode_extent_tree(&et, inode, bh);
+	status = ocfs2_lock_allocators(inode, &et, clusters_to_add, 0,
+				       &data_ac, &meta_ac);
+	ocfs2_put_extent_tree(&et);
 	if (status) {
 		mlog_errno(status);
 		goto leave;
@@ -1236,11 +1241,13 @@ static int __ocfs2_remove_inode_range(struct inode *inode,
 	handle_t *handle;
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct ocfs2_extent_tree et;
+
+	ocfs2_get_dinode_extent_tree(&et, inode, di_bh);
 
-	ret = ocfs2_lock_allocators(inode, di_bh, &di->id2.i_list,
-				    0, 1, NULL, &meta_ac,
-				    OCFS2_DINODE_EXTENT, NULL);
+	ret = ocfs2_lock_allocators(inode, &et, 0, 1, NULL, &meta_ac);
 	if (ret) {
+		ocfs2_put_extent_tree(&et);
 		mlog_errno(ret);
 		return ret;
 	}
@@ -1269,8 +1276,8 @@ static int __ocfs2_remove_inode_range(struct inode *inode,
 		goto out;
 	}
 
-	ret = ocfs2_remove_extent(inode, di_bh, cpos, len, handle, meta_ac,
-				  dealloc, OCFS2_DINODE_EXTENT, NULL);
+	ret = ocfs2_remove_extent(inode, &et, cpos, len, handle, meta_ac,
+				  dealloc);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
@@ -1297,6 +1304,7 @@ static int __ocfs2_remove_inode_range(struct inode *inode,
 	if (meta_ac)
 		ocfs2_free_alloc_context(meta_ac);
 
+	ocfs2_put_extent_tree(&et);
 	return ret;
 }
 

fs/ocfs2/suballoc.c

@@ -1914,12 +1914,11 @@ static inline void ocfs2_debug_suballoc_inode(struct ocfs2_dinode *fe)
  * File systems which don't support holes call this from
  * ocfs2_extend_allocation().
  */
-int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
-			  struct ocfs2_extent_list *root_el,
+int ocfs2_lock_allocators(struct inode *inode,
+			  struct ocfs2_extent_tree *et,
 			  u32 clusters_to_add, u32 extents_to_split,
 			  struct ocfs2_alloc_context **data_ac,
-			  struct ocfs2_alloc_context **meta_ac,
-			  enum ocfs2_extent_tree_type type, void *private)
+			  struct ocfs2_alloc_context **meta_ac)
 {
 	int ret = 0, num_free_extents;
 	unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
@@ -1931,8 +1930,7 @@ int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
 
 	BUG_ON(clusters_to_add != 0 && data_ac == NULL);
 
-	num_free_extents = ocfs2_num_free_extents(osb, inode, root_bh,
-						  type, private);
+	num_free_extents = ocfs2_num_free_extents(osb, inode, et);
 	if (num_free_extents < 0) {
 		ret = num_free_extents;
 		mlog_errno(ret);
@@ -1954,7 +1952,7 @@ int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
 	 */
 	if (!num_free_extents ||
 	    (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {
-		ret = ocfs2_reserve_new_metadata(osb, root_el, meta_ac);
+		ret = ocfs2_reserve_new_metadata(osb, et->et_root_el, meta_ac);
 		if (ret < 0) {
 			if (ret != -ENOSPC)
 				mlog_errno(ret);

fs/ocfs2/suballoc.h

@@ -165,10 +165,8 @@ u64 ocfs2_which_cluster_group(struct inode *inode, u32 cluster);
 int ocfs2_check_group_descriptor(struct super_block *sb,
 				 struct ocfs2_dinode *di,
 				 struct ocfs2_group_desc *gd);
-int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
-			  struct ocfs2_extent_list *root_el,
+int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_extent_tree *et,
 			  u32 clusters_to_add, u32 extents_to_split,
 			  struct ocfs2_alloc_context **data_ac,
-			  struct ocfs2_alloc_context **meta_ac,
-			  enum ocfs2_extent_tree_type type, void *private);
+			  struct ocfs2_alloc_context **meta_ac);
 #endif /* _CHAINALLOC_H_ */