On Thu, Aug 17, 2017 at 01:47:13PM -0400, Martin K. Petersen wrote: > > Lukas, > > > Do we also know that the blocks were discarded as we do with > > BLKDISCARD ? > > There never was a way to know for sure. > > ATA DSM TRIM and SCSI UNMAP are hints by definition. We attempted to > bend their semantics towards getting predictable behavior but ultimately > failed. Too many corner cases. I believe that eMMC and UFS does give you a way to get stronger guarantees. It's unfortunate that SATA did not get this right; it's even more unfortunate that for many drives it works 99% of the time. But yes, it's not a guarantee. - Ted
