FS hang with suspfs when creating snapshot on a UFS + GJOURNAL setup

[Pavel Gorshkov]

On Fri, Dec 28, 2012 at 01:27:24PM +0200, Konstantin Belousov wrote:
> Please try the following patch. It is against HEAD, might need some
> adjustments for 8. I do the resume and write accounting atomically,
> not allowing other suspension to intervent between.

So is this only limited to snapshot creation, or can it happen
during some other relatively heavy disk activity, e.g. trying to
build/install two ports simultaneously?
Because I have just experienced a very similar hang - not sure
about 'suspfs' though (couldn't run top).