On Wed, Feb 12, 2014 at 07:08:20PM -0700, Andreas Dilger wrote: > > What about FITRIM? I'm not sure of the exact semantics of ZBCRESETZONE, > but at first glance it seems similar to resetting an erase block on an > SSD. That might also be beneficial if the SMR drives have directly > addressible on-board flash that is mapped to a Z_FLAG_TYPE_RANDOM zone > type (I wish...) and it would pass the FITRIM straight through., it But that's not what the FITRIM ioctl does. The FITRIM ioctl is a request for the file system to send trim/discard for all blocks which are not in use by the file system. It doesn't map well to how ZBCRESETZONE. It is possible to map ZBCRESETZONE to BLKDISCARD, except that non-SMR/ZBC drives don't have a concept of a write pointer, so while it is true that the all of the data blocks are "reset" ala an erase block, with a MTD flash device, once an erase block is reset, you can write to any page within the rease block, in any order, whereas this is not true for an SMR/ZBC device. > For non-SSD "trim" it would just reset the SMR zone but not return zeroes. I think you are thinking of BLKDISCARD, not FITRIM. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
