[Libguestfs] [PATCH v2 06/11] resize: add support for logical partitions of calculate_target_partitions

[Chen Hanxiao]

This patch add support for logical partitions.

1) OpResize newsize:
  two additional parameter for resizing logical partitions:
  - gap_start
    For logical partitions, we had to reserce at least 1 gap
    between each other.
    Also, we may had an extra aligment between 1st logical partition
    and extended partition.
    We need to remove gap_start from 'OpResize newsize'

  - nr_logical
    number of logical partitions.
    We had to remove all size of gap between each logical partitions.
    each gap is in (1, alignment).
    So size = (nr_logical - 1) * alignment
    removed from size will be enough.

2) OpIgnore | OpCopy:
  If in logical partition, add an extra aligment of 1 sector.

Signed-off-by: Chen Hanxiao <chenhanxiao at cn.fujitsu.com>
---
 resize/resize.ml | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index c54ed2e..6a3d286 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -1083,13 +1083,17 @@ read the man page virt-resize(1).
    * the final list just contains partitions that need to be created
    * on the target.
    *)
-  let rec calculate_target_partitions partnum start ~create_surplus = function
+  let rec calculate_target_partitions partnum start ~create_surplus ?(nr_logical=0) ?(gap_start=0L) = function
     | p :: ps ->
       (match p.p_operation with
       | OpDelete ->
         calculate_target_partitions partnum start ~create_surplus ps (* skip p *)
 
       | OpIgnore | OpCopy ->          (* same size *)
+        (* add an extra gap for logical partitions *)
+        let alg = if p.p_mbr_p_type = LogicalPartition then 1L else 0L in
+        let start = roundup64 (start +^ alg) 2L in
+
         (* Size in sectors. *)
         let size = div_roundup64 p.p_part.G.part_size sectsize in
         (* Start of next partition + alignment. *)
@@ -1102,13 +1106,24 @@ read the man page virt-resize(1).
 
         { p with p_target_start = start; p_target_end = end_ -^ 1L;
           p_target_partnum = partnum } ::
-          calculate_target_partitions (partnum+1) next ~create_surplus ps
+          calculate_target_partitions (partnum+1) next ~create_surplus ~nr_logical ~gap_start ps
 
       | OpResize newsize ->           (* resized partition *)
+        (* add an extra gap for logical partitions *)
+        let alg = if p.p_mbr_p_type = LogicalPartition then 1L else 0L in
+
+        let start = roundup64 start 2L in
         (* New size in sectors. *)
         let size = div_roundup64 newsize sectsize in
+        (* remove gap_start from size *)
+        let size = size -^ gap_start in
+        (* remove max aligment between logical partitions *)
+        let size = size -^ ((Int64.of_int nr_logical) -^ 1L) *^ alignment in
         (* Start of next partition + alignment. *)
         let next = start +^ size in
+        (* We will reserve a 1-sector gap between logical partitions
+         * by decreasing current partition by 1 sector, see below. *)
+        let next = next -^ alg in
         let next = roundup64 next alignment in
 
         if verbose () then
-- 
2.1.0