resizing rootfs to fit the disk

[Paul Fox]

james wrote:
 > On Fri, Mar 05, 2010 at 01:39:23AM -0500, Paul Fox wrote:
 > > resize drags performance way down.  but "nice -19 resize2fs
 > > /dev/mmcblk0p2" only adds about 25% to the runtime (~50sec vs. 
 > > ~40sec),
 > 
 > Consider ionice for reducing the I/O priority of the task.
 > e.g.  ionice -c3 resize2fs ...
 > 
 > Also, did you get far with the kernel resize code?  Doing it in the
 > kernel seems tidier, and the code seems to be there.  One remounts with
 > resize option.

i've not been able to get "mount -o remount,resize" to work:
either i'm doing something wrong, or something's misconfigured,
or, well, or something.

however when resize2fs operates in online mode, i believe it's
using the kernel code -- it sort of has to.  looking at
resize/online.c in the e2fsprogs source tree, it seems most of
the work is done by a few ioctls, which call the same code that
would used by mount (via fs/ext3/super.c and fs/ext3/resize.c).

looking at the e2fsprogs changelog, there have been some bugs
fixed since the 1.41.4 version we're using, though not
surprisingly they mostly seem to be related to ext4 support, and
to the offline version of the code.  i haven't looked at the
kernel tree to see what fixes might have gone into the kernel
resize code since 2.6.31.6.

paul
=---------------------
 paul fox, pgf at laptop.org