SUSE reaffirms support for Btrfs

That wasn't the problem being discussed on the list, as I understood it. The problem there was that a drive had been told "FUA", there was a timeout because the drive's power (but not the system's power) was unreliable so the drive had forgotten the command was issued and lost its transient state, including its RAM; the kernel retried the command, got told "OK! Flushed!"... and indeed the cache had been flushed, but because of the power interruption the cache that was flushed was *empty*.

Perhaps any timeout at all should force all layers to assume that everything until the last *acknowledged* FUA is potentially lost? Regardless, turning off write caching isn't going to help there at all: any rotating-rust drive needs *somewhere* to store data between it being sent to the drive and its being committed to the disk: whether you call it a cache or not, its contents can be lost if power goes out at the wrong instant (indeed, if the write to the disk is underway you can get a torn sector and ECC recovery on the spinning rust too). The real lesson here is that operating reliably atop hardware with faulty power rails is about as easy as operating atop any other faulty hardware...