Re: [PATCH 2/2 v2] btrfs: add framework to read fs info and dev info from the kernel

[Anand Jain <Anand.Jain@oracle.com>]

  TREE_SEARCH ioctl doesn't help in this case
  the dev item don't provide all the info
  that btrfs-progs might need in the long run
  (and even the current needs).

Thanks, Anand

On 06/11/2013 10:24 PM, Josef Bacik wrote:
> On Mon, Jun 10, 2013 at 08:59:15AM -0600, Anand Jain wrote:
>> This adds two ioctl BTRFS_IOC_GET_FSIDS and BTRFS_IOC_GET_DEVS
>> which reads the btrfs_fs_devices and btrfs_device structure
>> from the kernel respectively.
>>
>> The information in these structure are useful to report the
>> device/fs information in line with the kernel operations and
>> thus immediately addresses the problem that 'btrfs fi show'
>> command reports the stale information after device device add
>> remove operation is performed. That is because btrfs fi show
>> reads the disks directly.
>>
>> Further the frame-work provided here would help to enhance
>> the btrfs-progs/library to read the other fs information and
>> its device information. Also the frame work provided here is
>> easily extensible to retrieve any other structure as future
>> needs.
>>
>> v1->v2:
>>    .code optimized
>>    .get the device generation number as well, so that
>>     btrfs-progs could print using print_one_uuid
>>
>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>
> In fact NACK altogether on this patch, you can get the same info out with the
> TREE_SEARCH ioctl, just do that in btrfs-progs and don't add yet another ioctl.
> Thanks,
>
> Josef