Re: [PATCH 1/2] Add partition resize function to BLKPG ioctl

From: Karel Zak
Date: Thu Dec 08 2011 - 10:17:03 EST


On Thu, Dec 08, 2011 at 09:22:12AM -0500, Phillip Susi wrote:
> On 12/8/2011 7:30 AM, Karel Zak wrote:
>> It seems very close to Vivek's BLKPG_EXTEND_PARTITION idea, see:
>>
>> https://lkml.org/lkml/2011/9/1/351
>>
>> It's evident that we (userspace) need something better than
>> BLKPG_{ADD,DEL}_* and BLKRRPART, but no response from kernel side :-(
>
> Yes, this looks very similar to mine, except that I also wanted to allow
> shrinking the partition, not just extending, since btrfs can handle this
> ( tested ).

Is it safe to alter the partition size in arbitrary way if the
partition is used by any process?

Vivek's BLKPG_EXTEND_PARTITIONV seems more safety, because it extends
a partition size only, so all offsets in all running stuff are still
valid.

Maybe you need to check bdevp->bd_openers and returns -EBUSY if you
want to alter the begin of the partition.

Karel


--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
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