Hello @cybik, this issue is already being tracked at #4982. Closing as a duplicate.
@kisak-valve is it though? the mentioned issue is mostly talking about the cli client as far as i can see (EDIT: nope it wasn't, i mistook it for #5180, but the remainder of my post still stands), and i suspect you guys not changing a single int for an uint64_t in years might be related to you thinking the (probably larger) user base for the GUI client are unaffected. fun fact: in the "manage libraries" screen you actually get it right:

but trying to install a game is still forbidden because you try to make your code think for the user and get it wrong:

PLEASE if you don't want to fix it at least allow us to ignore that calculation like pretty much EVERY other installer EVER does, and make that "yeah now you can't" dialog into a "you probably can't but do you want to try anyway" one.
updates to already installed games and the likes do actually work just fine, so there's no apparent reason for your code to depend on that broken calculation except "the user is stupid and we never make mistakes in our code" (which is proven wrong).
Also note this isn't zfs specific, the screenshots above happen on my 3tb ext4 drive, because of the same annoying integer overflowiness. if you people can't get your stuff to work on 64bit properly, at least make it ignorable. I'm barred from playing about 500$ worth of games because you dont have enough bits in a substraction -_-
Nothing extracted yet.
System information
Please describe your issue in as much detail as possible:
My Steam games reside on a zfs partition, and up until yesterday (with zfs 0.6.5.8) I could download games easily. It might be that the new zfs driver handles getting free space differently, but when I try to install a game now, Steam reports 0mb free on the partition, and the console logs show this:
../tier1/fileio.cpp (3264) : Assertion Failed: Failed to determine free disk space for /media/Games/cybik/Steam, error 75Meanwhile,
zfs listreturns this for free space info:Steps for reproducing this issue: