If the system is I/O bound, such as when removing a lot of files, or if there is a hung SSH process of a remotely mounted sshfs, plasmashell will hang. In the ksysguard process list, it shows up as being in "disk sleep". As soon as the heavy I/O operation finishes (or the hung ssh process is terminated), plasmashell becomes responsive again.

Reproducible: Always

Steps to Reproduce:
1. Remotely mount something through sshfs
2. Put your system to sleep for a few minutes
3. Wake the system, the ssh process should now be hanging. Shortly afterwards, plasmashell should enter disk sleep.

Alternatively,
1. Grab the GCC source through SVN
2. Build GCC
3. Run a recursive rm operation on the folder, and attempt to interact with plasmashell

Actual Results:  
plasmashell hangs until the I/O issue is resolved. For a stuck SSHFS mount, this usually means that the associated SSH task needs to be killed. plasmashell will not react to SIGKILL while it's in disk sleep mode.

Expected Results:  
plasmashell should have a timeout on non-essential I/O operations, or perform blocking I/O in a separate thread, as to ensure that user interactivity is not lost.

While this happened, a Dolphin window into the SSHFS mounted folder was opened. This might be related, so I'll add it here.

The system uses a Kingston SSD connected through mSATA, and uses ext4 as both the root and the /home file system.

While plasmashell is frozen, Ctrl+Escape for opening the system activity window still works, however, Alt+F2 to bring up KRunner doesn't. The volume keys also no longer work, which is a bit awkward when I click on a video and then notice that plasmashell is frozen.