+int ocfs2_check_range_for_refcount(struct inode *inode, loff_t pos,
+ size_t count)
+{
+ int ret = 0;
+ unsigned int extent_flags;
+ u32 cpos, clusters, extent_len, phys_cpos;
+ struct super_block *sb = inode->i_sb;
+
+ if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)) ||
+ !(OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL) ||
+ OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
+ return 0;
+
+ cpos = pos >> OCFS2_SB(sb)->s_clustersize_bits;
+ clusters = ocfs2_clusters_for_bytes(sb, pos + count) - cpos;
+
+ while (clusters) {
+ ret = ocfs2_get_clusters(inode, cpos, &phys_cpos, &extent_len,
+ &extent_flags);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ if (phys_cpos && (extent_flags & OCFS2_EXT_REFCOUNTED)) {
+ ret = 1;
+ break;
+ }
+
+ if (extent_len > clusters)
+ extent_len = clusters;
+
+ clusters -= extent_len;
+ cpos += extent_len;
+ }
+out:
+ return ret;
+}
+
+static int ocfs2_prepare_inode_for_refcount(struct inode *inode,
+ loff_t pos, size_t count,
+ int *meta_level)
+{
+ int ret;
+ struct buffer_head *di_bh = NULL;
+ u32 cpos = pos >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+ u32 clusters =
+ ocfs2_clusters_for_bytes(inode->i_sb, pos + count) - cpos;
+
+ ret = ocfs2_inode_lock(inode, &di_bh, 1);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ *meta_level = 1;
+
+ ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters, UINT_MAX);
+ if (ret)
+ mlog_errno(ret);
+out:
+ brelse(di_bh);
+ return ret;
+}
+