xfs: remove the data_dot_offset field in struct xfs_dir_ops

The data_dot_offset value is always equal to data_entry_offset given
that "." is always the first entry in the directory.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_da_format.c

@@ -204,7 +204,6 @@ static const struct xfs_dir_ops xfs_dir2_ops = {
 	.data_entry_tag_p = xfs_dir2_data_entry_tag_p,
 	.data_bestfree_p = xfs_dir2_data_bestfree_p,
 
-	.data_dot_offset = sizeof(struct xfs_dir2_data_hdr),
 	.data_dotdot_offset = sizeof(struct xfs_dir2_data_hdr) +
 				XFS_DIR2_DATA_ENTSIZE(1),
 	.data_first_offset =  sizeof(struct xfs_dir2_data_hdr) +
@@ -225,7 +224,6 @@ static const struct xfs_dir_ops xfs_dir2_ftype_ops = {
 	.data_entry_tag_p = xfs_dir3_data_entry_tag_p,
 	.data_bestfree_p = xfs_dir2_data_bestfree_p,
 
-	.data_dot_offset = sizeof(struct xfs_dir2_data_hdr),
 	.data_dotdot_offset = sizeof(struct xfs_dir2_data_hdr) +
 				XFS_DIR3_DATA_ENTSIZE(1),
 	.data_first_offset =  sizeof(struct xfs_dir2_data_hdr) +
@@ -246,7 +244,6 @@ static const struct xfs_dir_ops xfs_dir3_ops = {
 	.data_entry_tag_p = xfs_dir3_data_entry_tag_p,
 	.data_bestfree_p = xfs_dir3_data_bestfree_p,
 
-	.data_dot_offset = sizeof(struct xfs_dir3_data_hdr),
 	.data_dotdot_offset = sizeof(struct xfs_dir3_data_hdr) +
 				XFS_DIR3_DATA_ENTSIZE(1),
 	.data_first_offset =  sizeof(struct xfs_dir3_data_hdr) +

fs/xfs/libxfs/xfs_dir2.h

@@ -40,7 +40,6 @@ struct xfs_dir_ops {
 	struct xfs_dir2_data_free *
 		(*data_bestfree_p)(struct xfs_dir2_data_hdr *hdr);
 
-	xfs_dir2_data_aoff_t data_dot_offset;
 	xfs_dir2_data_aoff_t data_dotdot_offset;
 	xfs_dir2_data_aoff_t data_first_offset;
 	size_t	data_entry_offset;

fs/xfs/xfs_dir2_readdir.c

@@ -70,13 +70,12 @@ xfs_dir2_sf_getdents(
 		return 0;
 
 	/*
-	 * Precalculate offsets for . and .. as we will always need them.
-	 *
-	 * XXX(hch): the second argument is sometimes 0 and sometimes
-	 * geo->datablk
+	 * Precalculate offsets for "." and ".." as we will always need them.
+	 * This relies on the fact that directories always start with the
+	 * entries for "." and "..".
 	 */
 	dot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
-						dp->d_ops->data_dot_offset);
+			dp->d_ops->data_entry_offset);
 	dotdot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
 						dp->d_ops->data_dotdot_offset);