Description of problem:
NFSv4 supports SEEK_HOLE and SEEK_DATA and this can improve the handling of sparse files (like virtual machine images) a lot. Gluster is going to support this soon too, see bug 1220173 for more details.
Steps to Reproduce:
1. create a sparse file on a NFSv4 mountpoint (use 'qemu-img')
2. copy the sparse file from the NFSv4 mount to somewhere (use 'cp')
3. compare the allocated space of the two files
The copy is fully allocated.
The copy should have holes as well.
Does nfs-ganesha support SEEK_HOLE / SEEK_DATA these days?
Those features are part of NFSv4.2 protocol standard.
The support was added in 2.7 branch(current devel branch) https://review.gerrithub.io/#/c/ffilz/nfs-ganesha/+/393642/. But not available in stable releases.
If this is still an issue please open an issue in the github tracker at https://github.com/nfs-ganesha/nfs-ganesha/issues