+/*
+ * Routine to zero an extent on disk allocated to the specific inode.
+ *
+ * The VFS functions take a linearised filesystem block offset, so we have to
+ * convert the sparse xfs fsb to the right format first.
+ * VFS types are real funky, too.
+ */
+int
+xfs_zero_extent(
+ struct xfs_inode *ip,
+ xfs_fsblock_t start_fsb,
+ xfs_off_t count_fsb)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ xfs_daddr_t sector = xfs_fsb_to_db(ip, start_fsb);
+ sector_t block = XFS_BB_TO_FSBT(mp, sector);
+ ssize_t size = XFS_FSB_TO_B(mp, count_fsb);
+
+ if (IS_DAX(VFS_I(ip)))
+ return dax_clear_blocks(VFS_I(ip), block, size);
+
+ /*
+ * let the block layer decide on the fastest method of
+ * implementing the zeroing.
+ */
+ return sb_issue_zeroout(mp->m_super, block, count_fsb, GFP_NOFS);
+
+}
+