[dm-devel] [patch 0/2] [V4] block: Support online resize of disk partitions

[Vivek Goyal]

On Mon, Jul 09, 2012 at 05:34:18PM -0400, vivek.goyal2008 at gmail.com wrote:
> Hi,
> 
> Few people have pinged me in rencent past about status of this patch, hence,
> this is V4 of patch which adds support for online resizing of a partition.
> This patch is based on previously posted patches by Phillip Susi. 
> 

Hi Jens,

Can you please consider partition resize patches for inclusion.

Thanks
Vivek

> There are two patches. Out of which one is kernel patch and other one is
> util-linux patch to add support of a user space utility "resizepart" to
> allow resizing the partition.
> 
> This ioctl only resizes the partition size in kenrel and does not change
> the size on disk. A user needs to make sure that corresponding changes
> are made to disk data structures also using fdisk(or partx), if changes
> are to be retained across reboot.
> 
> Changes since V3
> ----------------
> - Do bdput() in error path as per the Maxim's review comments.
> 
> Changes since V2
> ----------------
> - Do not ignore the "start" parameter in RESIZE ioctl.
> - Change resizepart utility to parse sysfs to get to partition start.
> 
> Changes since V1
> ----------------
> Following are changes since the version Phillip posted.
> - RESIZE ioctl ignores the partition "start" and does not expect user to
>   specify one. Caller needs to just specify "device", "partition number" and
>   "size" of new partition.
> 
> - Got rid of part_nr_sects_write_begin/part_nr_sects_write_end functions
>   and replaced these with single part_nr_sects_write().
> 
> - Some sequence counter related changes are simply lifted from i_size_write().
> 
> - Initialized part->nr_sects_seq using seqcount_init().
> 
> Phillip, do let me know if I should put your signed-off-by also in the
> patch.
> 
> Any review feedback is welcome.
> 
> I did following test.
> 
> - Create a partition of 10MB on a disk using fdisk.
> - Add this partition to a volume group
> - Use fdisk to increase the partition size to 20MB. (First delete the
>   partition and then create a new one of 20MB size).
> - Use resizepart to extend partition size in kernel.
>         resizepart /dev/sdc 1 40960
> - Do pvresize on partition so that physical volume can be incrased in
>   size online.
>         pvresize /dev/sda1
> 
> pvresize does recognize the new size. Also lsblk and /proc/partitions
> report the new size of partition.
> 
> Thanks
> Vivek
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