Libguestfs - May 2015 - [PATCH v2 00/11] virt-resize: add support for resizing MBR logical partitions

In current virt-resize, only primary partitions(including
extended partition) are supported. They are collected in an
array for resize operations. Logical partitions are not
supported.

This series add support for resizing logical partitions.

v2:
 1) Add 3 variables to describe relationship of logical and extended partitions:
 - partitions
   flat list of primary partitions (as now, the global 'partitions').
    extended partitions is essentially  primary partition
 - logical_partitions
   flat list of logical partitions
 - extended_partition
   one MBR extended partition

  2) reserve enough size when resizing logical partitions

Original patches by Hu Tao at:
https://www.redhat.com/archives/libguestfs/2014-October/msg00238.html

Chen Hanxiao (11):
  resize: move loop check from find_partitions
  resize: add logical_partitions and extended_partition
  resize: updated find_partition to support logical partition
  resize: add support for logical partitions for calculate_surplus
  resize: handle resize of logical partitions
  resize: add support for logical partitions of
    calculate_target_partitions
  resize: calculate_target_partitions for logical partitions
  resize: parted and copy logical partitions
  resize: more misc ops on logical partition
  resize: add support resize extended partition
  resize: test: add support for resizing extended and logical partitions

 resize/resize.ml           | 189 ++++++++++++++++++++++++++++++++++-----------
 resize/test-virt-resize.pl |  32 ++------
 2 files changed, 149 insertions(+), 72 deletions(-)

-- 
2.1.0

As logical partitions laid inside extended partition,
overlap check will not work.
make loop as a individual function,
which could do a seperate check on logical/extended partitions.

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/resize.ml | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 602a583..4c97405 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -521,20 +521,20 @@ read the man page virt-resize(1).
       | _ -> ()
     ) partitions;
 
-    (* Check partitions don't overlap. *)
-    let rec loop end_of_prev = function
-      | [] -> ()
-      | { p_name = name; p_part = { G.part_start = part_start } } :: _
-          when end_of_prev > part_start ->
-        error (f_"%s: this partition overlaps the previous one") name
-      | { p_part = { G.part_end = part_end } } :: parts -> loop part_end
parts
-    in
-    loop 0L partitions;
-
     partitions in
 
   let partitions = find_partitions () in
 
+  (* Check partitions don't overlap. *)
+  let rec loop end_of_prev = function
+    | [] -> ()
+    | { p_name = name; p_part = { G.part_start = part_start } } :: _
+        when end_of_prev > part_start ->
+      error (f_"%s: this partition overlaps the previous one") name
+    | { p_part = { G.part_end = part_end } } :: parts -> loop part_end parts
+  in
+  loop 0L partitions;
+
   if verbose () then (
     printf "%d partitions found\n" (List.length partitions);
     List.iter (debug_partition ~sectsize) partitions
-- 
2.1.0

For MBR, logical partitions laid inside extended partition.
Add 3 variables to describe this:
 - partitions
  flat list of primary partitions (as now, the global 'partitions').
  extended partitions is essentially  primary partition

 - logical_partitions
  flat list of logical partitions

 - extended_partition
  one MBR extended partition

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/resize.ml | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 4c97405..d7a8ce1 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -26,19 +26,16 @@ module G = Guestfs
 (* Minimum surplus before we create an extra partition. *)
 let min_extra_partition = 10L *^ 1024L *^ 1024L
 
+(* mbr extended partition *)
+let extended_partition_list = []
+
 (* Command line argument parsing. *)
 type align_first_t = [ `Never | `Always | `Auto ]
 
 (* Source partition type. *)
 type parttype = MBR | GPT
 
-(* Data structure describing the source disk's partition layout.
- *
- * NOTE: For MBR, only primary/extended partitions are tracked here.
- * Logical partitions are contained within an extended partition, and
- * we don't track them (they are just copied within the extended
- * partition).  For the same reason we cannot resize logical partitions.
- *)
+(* Data structure describing the source disk's partition layout. *)
 type partition = {
   p_name : string;               (* Device name, like /dev/sda1. *)
   p_part : G.partition;          (* SOURCE partition data from libguestfs. *)
@@ -496,12 +493,6 @@ read the man page virt-resize(1).
             p_target_start = 0L; p_target_end = 0L }
       ) parts in
 
-    (* Filter out logical partitions.  See note above. *)
-    let partitions -      (* for GPT, all partitions are regarded as Primary
Partition,
-       * e.g. there is no Extended Partition or Logical Partition. *)
-      List.filter (fun p -> parttype <> MBR || p.p_mbr_p_type <>
LogicalPartition) partitions in
-
     (* Check content isn't larger than partitions.  If it is then
      * something has gone wrong and we shouldn't continue.  Old
      * virt-resize didn't do these checks.
@@ -533,11 +524,29 @@ read the man page virt-resize(1).
       error (f_"%s: this partition overlaps the previous one") name
     | { p_part = { G.part_end = part_end } } :: parts -> loop part_end parts
   in
+
+  let extended_partition_list = List.append
+    extended_partition_list
+    (List.filter (fun p -> parttype = MBR && p.p_mbr_p_type =
ExtendedPartition) partitions) in
+  let extended_partition = if (List.length extended_partition_list) > 0 then
+    List.hd extended_partition_list else List.hd partitions in
+  let logical_partitions +    List.filter (fun p -> parttype = MBR
&& p.p_mbr_p_type = LogicalPartition) partitions in
+  (* Filter out logical partitions.  See note above. *)
+  let partitions +    (* for GPT, all partitions are regarded as Primary
Partition,
+     * e.g. there is no Extended Partition or Logical Partition. *)
+    List.filter (fun p -> parttype <> MBR || p.p_mbr_p_type <>
LogicalPartition) partitions in
+
   loop 0L partitions;
+  loop 0L logical_partitions;
 
   if verbose () then (
     printf "%d partitions found\n" (List.length partitions);
-    List.iter (debug_partition ~sectsize) partitions
+    List.iter (debug_partition ~sectsize) partitions;
+    List.iter (debug_partition ~sectsize) logical_partitions;
+    if (List.length extended_partition_list) > 0 then
+      printf "%s is extended partition\n" extended_partition.p_name
     );
 
   (* Build a data structure describing LVs on the source disk. *)
-- 
2.1.0

As we splited the original partitions list to
partitions and logical_partitions.

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

diff --git a/resize/resize.ml b/resize/resize.ml
index d7a8ce1..92f7304 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -616,6 +616,8 @@ read the man page virt-resize(1).
     let hash = Hashtbl.create 13 in
     List.iter (fun ({ p_name = name } as p) -> Hashtbl.add hash name p)
       partitions;
+    List.iter (fun ({ p_name = name } as p) -> Hashtbl.add hash name p)
+      logical_partitions;
     fun ~option name ->
       let name          if String.length name < 5 || String.sub name 0 5
<> "/dev/" then
-- 
2.1.0

Add support for logical partitions.
 - count number of logical_partition (we've split partitions list)
 - don't count size of extended partition
   For it'll duplicate with logical partition, we'll count it later
 - we need at leat 1 gap between logical partitions.
   so --aligment=1 will be increased by 1

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/resize.ml | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 92f7304..a0ed713 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -741,8 +741,10 @@ read the man page virt-resize(1).
     (* We need some overhead for partitioning. *)
     let overhead        let maxl64 = List.fold_left max 0L in
+      (* We need at least 1 sector gap between logical partitions *)
+      let alignment = if alignment = 1L then 2L else alignment in
 
-      let nr_partitions = List.length partitions in
+      let nr_partitions = List.length partitions + List.length
logical_partitions in
 
       let gpt_start_sects = 64L in
       let gpt_end_sects = gpt_start_sects in
@@ -770,12 +772,23 @@ read the man page virt-resize(1).
     let required = List.fold_left (
       fun total p ->
         let newsize +          (* size of extended partition is calculated
seperately *)
+          if p.p_type = ContentExtendedPartition then 0L else
+            match p.p_operation with
+            | OpCopy | OpIgnore -> p.p_part.G.part_size
+            | OpDelete -> 0L
+            | OpResize newsize -> newsize in
+        total +^ newsize
+    ) 0L partitions in
+    let required = required +^ List.fold_left (
+      fun total p ->
+        let newsize            match p.p_operation with
           | OpCopy | OpIgnore -> p.p_part.G.part_size
           | OpDelete -> 0L
           | OpResize newsize -> newsize in
         total +^ newsize
-    ) 0L partitions in
+    ) 0L logical_partitions in
 
     let surplus = outsize -^ (required +^ overhead) in
 
-- 
2.1.0

This will re-calculate the size of logical partitions.
and take logical partitions' aligment into account.
Then update extended partition's OpResize.

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/resize.ml | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/resize/resize.ml b/resize/resize.ml
index a0ed713..c54ed2e 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -834,6 +834,30 @@ read the man page virt-resize(1).
     )
   );
 
+  (* handle resizing of logical partitions *)
+  List.iter (
+    fun p ->
+      if p.p_type = ContentExtendedPartition then (
+        let alignment = if alignment = 1L then 2L else alignment in
+        let size = roundup64 p.p_part.G.part_size sectsize in
+        let logical_sizes = List.fold_left (
+          fun total p ->
+            match p.p_operation with
+              | OpDelete -> total +^ 0L
+              (* the start of logical partitions is aligned *)
+              | OpCopy | OpIgnore -> total +^ (roundup64
p.p_part.G.part_size (alignment *^ sectsize))
+              | OpResize newsize -> total +^ roundup64 newsize (alignment *^
sectsize)
+          ) 0L logical_partitions in
+
+        (* the first logical partition is aligned *)
+        let logical_sizes = logical_sizes +^ alignment *^ sectsize in
+        if logical_sizes > size then
+          p.p_operation <- OpResize logical_sizes
+        (* don't touch the extended partition if logical sizes less
+         * than the original size *)
+      )
+  ) partitions;
+
   (* Calculate the final surplus.
    * At this point, this number must be >= 0.
    *)
@@ -892,6 +916,7 @@ read the man page virt-resize(1).
       wrap (text ^ "\n\n") in
 
     List.iter print_summary partitions;
+    List.iter print_summary logical_partitions;
 
     List.iter (
       fun ({ lv_name = name } as lv) ->
-- 
2.1.0

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@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

Pass gap_start and nr_logical to calculate_target_partitions
when calculating logical partitions.

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/resize.ml | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 6a3d286..89bcb30 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -1175,9 +1175,24 @@ read the man page virt-resize(1).
 
     calculate_target_partitions 1 start ~create_surplus:true partitions in
 
+  let logical_partitions +    let start = List.fold_left (
+      fun total p ->
+        match p.p_type with
+          | ContentExtendedPartition -> total +^ p.p_target_start
+          | _ -> total +^ 0L
+    ) 0L partitions in
+
+    let gap_start = (roundup64 (start +^ 1L) alignment) -^ start in
+    let nr_logical = List.length logical_partitions in
+    (* align logical partitions, too *)
+    let start = roundup64 (start +^ 1L) alignment in
+    calculate_target_partitions 5 start ~create_surplus:false ~nr_logical
~gap_start logical_partitions in
+
   if verbose () then (
     printf "After calculate target partitions:\n";
-    List.iter (debug_partition ~sectsize) partitions
+    List.iter (debug_partition ~sectsize) partitions;
+    List.iter (debug_partition ~sectsize) logical_partitions
   );
 
   let mbr_part_type x -- 
2.1.0

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/resize.ml | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 89bcb30..db7e0b3 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -1210,6 +1210,11 @@ read the man page virt-resize(1).
       g#part_add "/dev/sdb" (mbr_part_type p) p.p_target_start
p.p_target_end
   ) partitions;
 
+  List.iter (
+    fun p ->
+      g#part_add "/dev/sdb" "logical" p.p_target_start
p.p_target_end
+  ) logical_partitions;
+
   (* Copy over the data. *)
   let copy_partition p        match p.p_operation with
@@ -1234,24 +1239,12 @@ read the man page virt-resize(1).
          | ContentUnknown | ContentPV _ | ContentFS _ ->
            g#copy_device_to_device ~size:copysize ~sparse source target
 
-         | ContentExtendedPartition ->
-           (* You can't just copy an extended partition by name, eg.
-            * source = "/dev/sda2", because the device name only
covers
-            * the first 1K of the partition.  Instead, copy the
-            * source bytes from the parent disk (/dev/sda).
-            *
-            * You can't write directly to the extended partition,
-            * because the size of it reported by Linux is always 1024
-            * bytes. Instead, write to the offset of the extended
-            * partition in the destination disk (/dev/sdb).
-            *)
-           let srcoffset = p.p_part.G.part_start in
-           let destoffset = p.p_target_start *^ 512L in
-           g#copy_device_to_device ~srcoffset ~destoffset ~size:copysize
"/dev/sda" "/dev/sdb"
+         | ContentExtendedPartition -> ()
         )
       | OpIgnore | OpDelete -> ()
   in
   List.iter copy_partition partitions;
+  List.iter copy_partition logical_partitions;
 
   (* Set bootable and MBR IDs.  Do this *after* copying over the data,
    * so that we can magically change the primary partition to an extended
-- 
2.1.0

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/resize.ml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/resize/resize.ml b/resize/resize.ml
index db7e0b3..37b946e 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -1274,6 +1274,7 @@ read the man page virt-resize(1).
       | GPT, (No_ID|MBR_ID _) | MBR, (No_ID|GPT_Type _) -> ()
   in
   List.iter set_partition_bootable_and_id partitions;
+  List.iter set_partition_bootable_and_id logical_partitions;
 
   (* Fix the bootloader if we aligned the first partition. *)
   if align_first_partition_and_fix_bootloader then (
@@ -1325,6 +1326,13 @@ read the man page virt-resize(1).
         can_expand_content p.p_type
       | { p_operation = (OpCopy | OpIgnore | OpDelete) } -> false
     ) partitions
+    ||
+    List.exists (
+      function
+      | ({ p_operation = OpResize _ } as p) ->
+        can_expand_content p.p_type
+      | { p_operation = (OpCopy | OpIgnore | OpDelete) } -> false
+    ) logical_partitions
     || List.exists (
       function
       | ({ lv_operation = LVOpExpand } as lv) ->
@@ -1386,6 +1394,7 @@ read the man page virt-resize(1).
         -> ()
     in
     List.iter expand_partition_content partitions;
+    List.iter expand_partition_content logical_partitions;
 
     (* Expand logical volume content as required. *)
     List.iter (
-- 
2.1.0

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/resize.ml | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 37b946e..8cdc5b1 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -769,6 +769,29 @@ read the man page virt-resize(1).
         start_overhead_sects +^ alignment_sects +^ gpt_end_sects in
       sectsize *^ overhead_sects in
 
+    let required_logical = List.fold_left (
+      fun total p ->
+        let newsize +          match p.p_operation with
+          | OpCopy | OpIgnore -> roundup64 p.p_part.G.part_size (alignment
*^ sectsize)
+          | OpDelete -> 0L
+          | OpResize newsize -> roundup64 newsize (alignment *^ sectsize) in
+        total +^ newsize
+    ) 0L logical_partitions in
+
+    let required_extended = List.fold_left (
+      fun total p ->
+        let newsize +        match p.p_type with
+        | ContentExtendedPartition ->
+          (* resizing extended partition by --resize or --expand is supported
*)
+          (match p.p_operation with
+           | OpResize newsize -> newsize
+           | _ -> p.p_part.G.part_size)
+        | _ -> 0L in
+        total +^ newsize
+    ) 0L partitions in
+
     let required = List.fold_left (
       fun total p ->
         let newsize @@ -780,15 +803,8 @@ read the man page virt-resize(1).
             | OpResize newsize -> newsize in
         total +^ newsize
     ) 0L partitions in
-    let required = required +^ List.fold_left (
-      fun total p ->
-        let newsize -          match p.p_operation with
-          | OpCopy | OpIgnore -> p.p_part.G.part_size
-          | OpDelete -> 0L
-          | OpResize newsize -> newsize in
-        total +^ newsize
-    ) 0L logical_partitions in
+    let required = required +^ if required_extended > required_logical
+    then required_extended else required_logical in
 
     let surplus = outsize -^ (required +^ overhead) in
 
@@ -840,6 +856,8 @@ read the man page virt-resize(1).
       if p.p_type = ContentExtendedPartition then (
         let alignment = if alignment = 1L then 2L else alignment in
         let size = roundup64 p.p_part.G.part_size sectsize in
+        (* resizing extended partition by --resize or --expand is supported *)
+        let size = match p.p_operation with OpResize s -> s | _ -> size
in
         let logical_sizes = List.fold_left (
           fun total p ->
             match p.p_operation with
-- 
2.1.0

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
---
 resize/test-virt-resize.pl | 32 +++++---------------------------
 1 file changed, 5 insertions(+), 27 deletions(-)

diff --git a/resize/test-virt-resize.pl b/resize/test-virt-resize.pl
index be9c9b4..85ed1b2 100755
--- a/resize/test-virt-resize.pl
+++ b/resize/test-virt-resize.pl
@@ -75,13 +75,6 @@ if (rand () <= 0.5) {
 # an extended partition (#4) and zero or more logical partitions.
 my $nr_parts = 1 + int (rand (7));
 
-# XXX Temporarily restriction XXX
-# Currently virt-resize is broken when dealing with any extended
-# partition, so don't test this for the moment.
-if ($part_type eq "mbr" && $nr_parts >= 4) {
-    $nr_parts = 3;
-}
-
 # expand (1) or shrink (0)
 my $expand = 0;
 if (rand () >= 0.2) {
@@ -120,31 +113,16 @@ my $i;
 for ($i = 1; $i <= $nr_parts; ++$i) {
     $parts[$i] = { name => "sda".$i, resize => 0 };
 
-    if ($part_type eq "mbr") {
-        if ($i < 4) {
-            if (rand () < 0.5) {
-                $parts[$i]->{resize} = 1;
-            }
-        } elsif ($i == 4) {
+    if ($part_type eq "mbr" && $i == 4) {
             $parts[$i]->{content} = "extended";
-        }
-    } else {
-        if (rand () < 0.5) {
-            $parts[$i]->{resize} = 1;
-        }
+    }
+    if (rand () < 0.5) {
+        $parts[$i]->{resize} = 1;
     }
 }
 
 # Pick a partition at random to expand or shrink.
-if ($part_type eq "mbr") {
-    # virt-resize cannot shrink extended or logical partitions, so we
-    # set $max so that these cannot be chosen:
-    my $max = 3;
-    $max = $nr_parts if $max > $nr_parts;
-    $i = 1 + int (rand ($max));
-} else {
-    $i = 1 + int (rand ($nr_parts));
-}
+$i = 1 + int (rand ($nr_parts));
 $parts[$i]->{resize} = 0;
 $parts[$i]->{expand_shrink} = 1;
 
-- 
2.1.0

> -----Original Message-----
> From: libguestfs-bounces@redhat.com [mailto:libguestfs-bounces@redhat.com]
On
> Behalf Of Chen Hanxiao
> Sent: Wednesday, May 20, 2015 6:51 PM
> To: libguestfs@redhat.com
> Subject: [Libguestfs] [PATCH v2 00/11] virt-resize: add support for
resizing MBR
> logical partitions
> 
> In current virt-resize, only primary partitions(including
> extended partition) are supported. They are collected in an
> array for resize operations. Logical partitions are not
> supported.
> 
> This series add support for resizing logical partitions.
> 
> v2:
>  1) Add 3 variables to describe relationship of logical and extended
partitions:
>  - partitions
>    flat list of primary partitions (as now, the global
'partitions').
>     extended partitions is essentially  primary partition
>  - logical_partitions
>    flat list of logical partitions
>  - extended_partition
>    one MBR extended partition
> 
>   2) reserve enough size when resizing logical partitions
> 
> Original patches by Hu Tao at:
> https://www.redhat.com/archives/libguestfs/2014-October/msg00238.html
> 
> Chen Hanxiao (11):
>   resize: move loop check from find_partitions
>   resize: add logical_partitions and extended_partition
>   resize: updated find_partition to support logical partition
>   resize: add support for logical partitions for calculate_surplus
>   resize: handle resize of logical partitions
>   resize: add support for logical partitions of
>     calculate_target_partitions
>   resize: calculate_target_partitions for logical partitions
>   resize: parted and copy logical partitions
>   resize: more misc ops on logical partition
>   resize: add support resize extended partition
>   resize: test: add support for resizing extended and logical partitions
> 
>  resize/resize.ml           | 189
++++++++++++++++++++++++++++++++++-----------
>  resize/test-virt-resize.pl |  32 ++------
>  2 files changed, 149 insertions(+), 72 deletions(-)
> 
Hi, Rich

Any comments on this series?

Regards,
- Chen

On Wed, May 20, 2015 at 06:51:28AM -0400, Chen Hanxiao
wrote:
> For MBR, logical partitions laid inside extended partition.
> Add 3 variables to describe this:
>  - partitions
>   flat list of primary partitions (as now, the global
'partitions').
>   extended partitions is essentially  primary partition
> 
>  - logical_partitions
>   flat list of logical partitions
> 
>  - extended_partition
>   one MBR extended partition
> 
> Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
> ---
>  resize/resize.ml | 37 +++++++++++++++++++++++--------------
>  1 file changed, 23 insertions(+), 14 deletions(-)
> 
> diff --git a/resize/resize.ml b/resize/resize.ml
> index 4c97405..d7a8ce1 100644
> --- a/resize/resize.ml
> +++ b/resize/resize.ml
> @@ -26,19 +26,16 @@ module G = Guestfs
>  (* Minimum surplus before we create an extra partition. *)
>  let min_extra_partition = 10L *^ 1024L *^ 1024L
>  
> +(* mbr extended partition *)
> +let extended_partition_list = []
This assignment doesn't really do anything.  'let' bindings in OCaml
don't create global variables.  This just makes
'extended_partition_list' be a name for the empty list, ...

[...]
> +  let extended_partition_list = List.append
> +    extended_partition_list
... up to here, where you create a second name, also
'extended_partition_list', completely independent from the one above,
which for no reason appends to the empty list.

What *doesn't* happen is 'extended_partition_list' that you created
at
the top is modified.
> +  let extended_partition = if (List.length extended_partition_list) > 0
then
> +    List.hd extended_partition_list else List.hd partitions in
You could write this more naturally as:

  let extended_partition     match extended_partition_list with
    | h :: _ -> h
    | [] -> List.hd partitions in

Rewriting it like this also makes the bug in this code clearer: why is
extended_partition initialized to the first partition, if there are no
extended partitions?

I think you probably meant to write:

  let extended_partition     match extended_partition_list with
    | h :: _ -> Some h
    | [] -> None in

> +  let logical_partitions > +    List.filter (fun p -> parttype = MBR
&& p.p_mbr_p_type = LogicalPartition) partitions in
> +  (* Filter out logical partitions.  See note above. *)
> +  let partitions > +    (* for GPT, all partitions are regarded as
Primary Partition,
> +     * e.g. there is no Extended Partition or Logical Partition. *)
> +    List.filter (fun p -> parttype <> MBR || p.p_mbr_p_type
<> LogicalPartition) partitions in
Although this is code is correct, it is clearer and shorter to write
the test using a separate function, so it would become:

  let is_logical_partition p     parttype = MBR && p.p_mbr_p_type =
LogicalPartition
  in
  let logical_partitions = List.filter is_logical_partition partitions in
  let partitions     List.filter (fun p -> not (is_logical_partition p))
partitions in

Rich.

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On Wed, May 20, 2015 at 06:51:29AM -0400, Chen Hanxiao
wrote:
> As we splited the original partitions list to
> partitions and logical_partitions.
> 
> Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
> ---
>  resize/resize.ml | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/resize/resize.ml b/resize/resize.ml
> index d7a8ce1..92f7304 100644
> --- a/resize/resize.ml
> +++ b/resize/resize.ml
> @@ -616,6 +616,8 @@ read the man page virt-resize(1).
>      let hash = Hashtbl.create 13 in
>      List.iter (fun ({ p_name = name } as p) -> Hashtbl.add hash name p)
>        partitions;
> +    List.iter (fun ({ p_name = name } as p) -> Hashtbl.add hash name p)
> +      logical_partitions;
>      fun ~option name ->
>        let name >          if String.length name < 5 || String.sub
name 0 5 <> "/dev/" then
If we're going to group these patches together, this should be merged
into the previous patch.

Rich.

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On Wed, May 20, 2015 at 06:51:30AM -0400, Chen Hanxiao
wrote:
> Add support for logical partitions.
>  - count number of logical_partition (we've split partitions list)
>  - don't count size of extended partition
>    For it'll duplicate with logical partition, we'll count it later
>  - we need at leat 1 gap between logical partitions.
>    so --aligment=1 will be increased by 1
> 
> Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
> ---
>  resize/resize.ml | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/resize/resize.ml b/resize/resize.ml
> index 92f7304..a0ed713 100644
> --- a/resize/resize.ml
> +++ b/resize/resize.ml
> @@ -741,8 +741,10 @@ read the man page virt-resize(1).
>      (* We need some overhead for partitioning. *)
>      let overhead >        let maxl64 = List.fold_left max 0L in
> +      (* We need at least 1 sector gap between logical partitions *)
> +      let alignment = if alignment = 1L then 2L else alignment in
>  
> -      let nr_partitions = List.length partitions in
> +      let nr_partitions = List.length partitions + List.length
logical_partitions in
I don't understand this at all.  Why do logical partitions count
towards the surplus?  I don't think they do.

Rich.
>        let gpt_start_sects = 64L in
>        let gpt_end_sects = gpt_start_sects in
> @@ -770,12 +772,23 @@ read the man page virt-resize(1).
>      let required = List.fold_left (
>        fun total p ->
>          let newsize > +          (* size of extended partition is
calculated seperately *)
> +          if p.p_type = ContentExtendedPartition then 0L else
> +            match p.p_operation with
> +            | OpCopy | OpIgnore -> p.p_part.G.part_size
> +            | OpDelete -> 0L
> +            | OpResize newsize -> newsize in
> +        total +^ newsize
> +    ) 0L partitions in
> +    let required = required +^ List.fold_left (
> +      fun total p ->
> +        let newsize >            match p.p_operation with
>            | OpCopy | OpIgnore -> p.p_part.G.part_size
>            | OpDelete -> 0L
>            | OpResize newsize -> newsize in
>          total +^ newsize
> -    ) 0L partitions in
> +    ) 0L logical_partitions in
>  
>      let surplus = outsize -^ (required +^ overhead) in
>  
> -- 
> 2.1.0
> 
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Fedora Windows cross-compiler. Compile Windows programs, test, and
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