I've tried that with no success. I started by trying to decrease the size of the home partition with parted. I found that if you umount /home, it automatically remounts (maybe there's an mtab option or service that controls this, not sure). That was keeping me from even starting parted on that partition. However I did come up with a kludge:
umount /home ; fsck /dev/mmcblk0p10
then immediately hit ctrl-Z before fsck finishes. Now /home appears to remain unmounted and I can run parted. However, deleting and recreating the /home partition with a smaller size didn't really seem to work and caused the Edison to fail to boot.
I agree that it certainly would be nice to have a way to resize partitions in a live Yocto image.
although it scares me (for no sound reason, only that it "feels" inelegant - lol), you're quite right: technically, using parted/resize2fs or other equivalents, should not only work with online FS, but be safe.
hrm, I can
sudo umount /home
with no problem. although this is with ubilinux. and neither fstab nor mtab have anything weird-looking. quite possibly yocto has other ideas...?
I'm not doing any e.g production of a huge amount of Edisons, so my lazy carcass has been happy enough to simply move+symlink large stuff into /home and/or USB.
not sure about the sparkfun SD boards, but I am really happy now having finally gotten the arduino-variant - the transflash slot janks directly into the SD controller and not thru clunky USB, so this is an inexpensive, effective way to add fast+useful diskspace. (Intel's own mini board can technically do this as well, as long as you're in the mood for soldering...)