Comment 15 for bug 955272

In testing "mkfs.ext4 -E resize=536870912", it results in no additional space utilization, while allowing a full resize to 2TB. My test case was to create a two new 2G filesystems, copy over a cloud image root.tar.gz to both, then resize one to 2TB.

/dev/loop1 2.0G 803M 1.1G 42% /mnt/test/small_disk
/dev/loop0 2.0T 800M 1.9T 1% /mnt/test/big_disk

The resize times are on the order of 11-20minutes.

However, since using "-E resize=..." doesn't increase the size of the disk and works, I think that this is a sane approach. I want to do a test build through the build system and have Neil verify, but I see no reason why not to enable this. The danger I see to this apporach, however, is that the default journal size on these small cloud images is 64MB. I seriously doubt that if you have 2TB of disk that a 64MB journal is going to cut it.