I must have overlooked one setting in Samba when I was trying to eliminate its configuration as a source for this issue: strict allocate = yes This seems to be what caused the problem. Sorry for the falsely attributed bug report, but maybe it's interesting information - I still think it's weird that this only caused an issue with FUSE/MHDDFS, not the other share I was using.
- Bug#911118: mhddfs hangs for a while on writing Marcél Ströhle
- Bug#911118: I think I've fixed it... Marcél