As far as I remember, in that case you still will be able to get a directory handle (with appropriate permissions), but calling FlushFileBuffers() on it is going to fail.
So you can test for that in advance before the restore and switch to syncing each file individually. Or accept that the approach only works locally and do nothing more, since durability over SMB is a questionable thing.
As far I remember NAND/NOR memory (used for SSD) is very slow to *erase*. The erase operation can be performed only by big chunks, requires higher voltage etc.
SSD vendors circumvent this by adding several layers of write buffers to achieve good test results.