On Thu, Mar 30 2017 at 7:44am -0400, Christoph Hellwig <hch@xxxxxx> wrote: > On Thu, Mar 30, 2017 at 12:06:41PM +0200, Lars Ellenberg wrote: > > > Will it make an fstrim cause thinly provisioned > > devices to suddenly be fully allocated? > > Not for SCSI devices. Yes for dm-thinp until it implements > REQ_OP_WRITE_ZEROES, which will hopefully be soon. I can work on this now. Only question I have is: should DM thinp take care to zero any misaligned head and tail? (I assume so but with all the back and forth between Bart, Paolo and Martin I figured I'd ask explicitly).