xfs: adjust refcount of an extent of blocks in refcount btree

Provide functions to adjust the reference counts for an extent of
physical blocks stored in the refcount btree.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_error.h b/fs/xfs/xfs_error.h
index 3d22470..d9675c64 100644
--- a/fs/xfs/xfs_error.h
+++ b/fs/xfs/xfs_error.h
@@ -92,7 +92,8 @@
 #define XFS_ERRTAG_BMAPIFORMAT				21
 #define XFS_ERRTAG_FREE_EXTENT				22
 #define XFS_ERRTAG_RMAP_FINISH_ONE			23
-#define XFS_ERRTAG_MAX					24
+#define XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE		24
+#define XFS_ERRTAG_MAX					25
 
 /*
  * Random factors for above tags, 1 means always, 2 means 1/2 time, etc.
@@ -121,6 +122,7 @@
 #define	XFS_RANDOM_BMAPIFORMAT				XFS_RANDOM_DEFAULT
 #define XFS_RANDOM_FREE_EXTENT				1
 #define XFS_RANDOM_RMAP_FINISH_ONE			1
+#define XFS_RANDOM_REFCOUNT_CONTINUE_UPDATE		1
 
 #ifdef DEBUG
 extern int xfs_error_test_active;