[Libguestfs] [PATCH] resize: fix 'No space left on device' problem when copying to an extended partition (RHBZ#1169015)

[Hu Tao]

Because of the size of an extended partition reported by Linux is always 1024
bytes, so it will always fail to copy to an extended partition.

This patch fixes this problem by copying to the offset of an extended
partition in the destination disk.

Signed-off-by: Hu Tao <hutao at cn.fujitsu.com>
---
 resize/resize.ml | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 363e2b6..ca5f87d 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -1139,9 +1139,15 @@ read the man page virt-resize(1).
             * 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
-           g#copy_device_to_device ~srcoffset ~size:copysize "/dev/sda" target
+           let destoffset = p.p_target_start *^ 512L in
+           g#copy_device_to_device ~srcoffset ~destoffset ~size:copysize "/dev/sda" "/dev/sdb"
         )
       | OpIgnore | OpDelete -> ()
   in
-- 
1.9.3