svn commit: r289203 - head/usr.sbin/makefs

[NGie Cooper]

> On Oct 12, 2015, at 19:32, Adrian Chadd <adrian at freebsd.org> wrote:
> 
> Author: adrian
> Date: Tue Oct 13 02:32:15 2015
> New Revision: 289203
> URL: https://svnweb.freebsd.org/changeset/base/289203
> 
> Log:
>  makefs: introduce a new option to specify what to round the resulting
>  image up to.
> 
>  From ticket:
> 
>  While trying to run FreeBSD/mips on some device having very small flash media,
>  one is forced to compress file system with mkulzma(8) utility. It is desirable
>  to specify small UFS block/fragment sizes like 4096/512 bytes for makefs(8)
>  and big compression block size like 65535 bytes to mkulzma at the same time.
>  Then one obtains very good comression ratios (like 75% and more) but faces
>  the following problem.
> 
>  geom_uncompress kernel module reports GEOM provider size rounded up to its
>  compression block size. Generally, this changes original media size and now
>  it fails to match the size of embedded UFS file system that leads to other
>  problems, f.e. geom_label kernel module does not like this and skips the
>  file system while tasting the GEOM and looking for UFS label.
> 
>  This makes it impossible to refer to the file system using known UFS label
>  instead of something like /dev/map/rootfs.uncompress.
> 
>  The following patch introduces new command line option "-r roundup" for makefs
>  that makes it round up the image to specified block size. Hence, geom_uncompress
>  does not change GEOM media size for images rounded that way and geom_label
>  accepts such GEOMs just fine.
> 
>  With the patch applied, one can use following commands:
> 
>  $ makefs -t ffs -r 65536 -o bsize=4096,fsize=512,label=flash optimization=space fs.img fs
>  $ mkulzma -s 65536 -o fs.img.ulzma fs.img
> 
>  PR:		bin/203707
>  Submitted by:	<eugen at grosbein.net>

1. roundup doesn’t seem like a user-friendly name.
2. “roundup” isn’t documented under the FFS-specific options.

I’m going to send out a CR soon updating the documentation and changing -r to -R.

Thanks,
-NGie