build: Add TARGET_ROOTFS_RESERVED_PCT option to reduce wasted space
The genext2fs tool will 'reserve' 5% of the image size by default,
apparently by creating a huge lost+found directory. In fact it seemed to
be much more than 5% in practice — I saw an image with 8MiB used, and
recovered about 2MiB of it by deleting the 'empty' lost+found directory:
/dev/loop0 48377 8482 37438 19% /mnt/spare
# rmdir lost+found/
/dev/loop0 48377 6014 39906 14% /mnt/spare
This makes it configurable, but leaves it at the genext2fs default
of 5% for now. It should probably be changed to default to zero, but
that can be a separate patch.
Signed-off-by: David Woodhouse <[email protected]>
Signed-off-by: Gabor Juhos <[email protected]>
SVN-Revision: 34408
Gabor Juhos