[Sugar-devel] Building a customized image of Sugar .100

[James Cameron]

On Sun, Aug 10, 2014 at 12:24:38PM -0300, Gustavo Duarte wrote:
> fiemap ioctl() failed
> zhashfs: zhashfs.c:156: read_extents: Assertion `(fiemap != ((void *)0))'
> failed.

The FIEMAP feature is not supported on your NFS.  It isn't clear that
it will remain unsupported; there seems ample mention of the
combination in a quick Google.

When I built the sparse .zd feature I used a pattern fill of unused
blocks to recognise them [1], but when Daniel Drake merged this he
used FIEMAP [2].

To avoid the problem, you may either:

- use eMMC or SD card,

- use USB FLASH or hard drive,

- use the network block device (nbd-server, nbd-client), or;

- use the loopback block device (losetup) over NFS.

You can also use a version of bin/zhashfs.c before the change, but you
will also have to change how the empty image is created.

References:

[1]
http://wiki.laptop.org/go/User:Quozl/fs-update-skip-unused-blocks#Pattern_Fill_Unused_Blocks

[2]
http://dev.laptop.org/git/projects/olpc-os-builder/commit/?id=bf0e0408ad49a32d733883c3bc832be0717b0298

-- 
James Cameron
http://quozl.linux.org.au/