[Buildroot] [PATCH 4/4] board/raspberrypi: auto-expand rootfs on first boot

["Benoît Thébaudeau" <benoit@wsystem.com>]

On 28/08/2015 12:36, Beno?t Th?baudeau wrote:
> On 27/08/2015 23:22, J?r?me Pouiller wrote:
>> On Thursday 27 August 2015 11:02:02 Beno?t Th?baudeau wrote:
>>> Hi Vivien, Yann, all,
>>>
>>> On 22/08/2015 22:01, Beno?t Th?baudeau wrote:
>> [...]
>>> So the initial contents of the unused space on the SD card seem to have an
>>> influence, and there seems to be a bug somewhere (Linux, resize2fs,
>>> genext2fs, tune2fs, or lack of call to e2fsck before calling resize2fs but
>>> this would not be reliable with an online partition).
>>>
>>> Then I retried with a 16-GiB SD card on a Raspberry Pi B, and it was very
>>> slow too. Same if the resize is performed on a PC. However, it's very quick
>>> with raspi-config and the latest Raspbian image. The main difference seemed
>>> to be the block size (4 KiB on Raspbian vs. 1 KiB with mke2img), so I
>>> hacked mke2img to test with genext2fs -B 4096 and tune2fs -J size=4, but it
>>> did not make things faster, only the image bigger (about 512 MiB, probably
>>> the minimal size for 4-KiB blocks). So I don't know which ones, but it's
>>> probably some ext4 parameters that are having an influence on the resize2fs
>>> speed here. Any idea?
>> Yes, I have an idea :-) Did you try sparse_super?
> 
> [...]
> 
> Awesome, it works, even if resizing the partition online. Thanks for the tip!
> 
> I'll send a patch changing mke2img to allow the use of this option.

Please apply the patch below before this series in order to avoid the resize
speed issue described above:
http://patchwork.ozlabs.org/patch/511861/

Best regards,
Beno?t