xfs: only assert new size for datafork during truncate extents

The assertion functions properly because we currently only truncate the
attr to a zero size. Any other new size of the attr is not preempted.
Make this assertion is specific to the datafork, preparing for
subsequent patches to truncate the attribute to a non-zero size.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Long Li <leo.lilong@huawei.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Author: Long Li

fs/xfs/xfs_inode.c

@@ -1048,7 +1048,8 @@ xfs_itruncate_extents_flags(
 	xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
 	if (icount_read(VFS_I(ip)))
 		xfs_assert_ilocked(ip, XFS_IOLOCK_EXCL);
-	ASSERT(new_size <= XFS_ISIZE(ip));
+	if (whichfork == XFS_DATA_FORK)
+		ASSERT(new_size <= XFS_ISIZE(ip));
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 	ASSERT(ip->i_itemp != NULL);
 	ASSERT(ip->i_itemp->ili_lock_flags == 0);