xfs: remove the special COW fork handling in xfs_bmapi_read

We don't call xfs_bmapi_read for the COW fork anymore, so remove the
special casing.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_bmap.c

@@ -3902,8 +3902,7 @@ xfs_bmapi_read(
 	int			whichfork = xfs_bmapi_whichfork(flags);
 
 	ASSERT(*nmap >= 1);
-	ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK|XFS_BMAPI_ENTIRE|
-			   XFS_BMAPI_COWFORK)));
+	ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK | XFS_BMAPI_ENTIRE)));
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED|XFS_ILOCK_EXCL));
 
 	if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(ip, whichfork)) ||
@@ -3918,16 +3917,6 @@ xfs_bmapi_read(
 
 	ifp = XFS_IFORK_PTR(ip, whichfork);
 	if (!ifp) {
-		/* No CoW fork?  Return a hole. */
-		if (whichfork == XFS_COW_FORK) {
-			mval->br_startoff = bno;
-			mval->br_startblock = HOLESTARTBLOCK;
-			mval->br_blockcount = len;
-			mval->br_state = XFS_EXT_NORM;
-			*nmap = 1;
-			return 0;
-		}
-
 		/*
 		 * A missing attr ifork implies that the inode says we're in
 		 * extents or btree format but failed to pass the inode fork